JP2003338213A - Light guide plate and plane lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent visible spectra (rainbow) by an optical element of the like and a dark streak pattern to obtain high-intensity output light. <P>SOLUTION: A light guide plate 2 has an incident part 7 guiding the light from a light source 3, a front surface part 8 causing the light to go out and a back surface part 9 located on a side opposite to the front surface part 8. Optical elements 20 having an inclined surface corresponding to the light flux from the light source 3 with continuity at a position corresponding to a luminance distribution or a light energy distribution of the light source 3 are laid on the front surface part 8 or/and the back surface part 9 with a density distribution functionally increasing in proportion to a distance from the light source 3. First optical deflection elements 30 in a concave or/and convex form finer than the optical element 20 are provided between continuous rows of the optical elements 20. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate and a flat lighting device used for a liquid crystal display device or the like, and for any light source, it is continuously positioned at a position corresponding to the brightness distribution or light energy distribution of the light source. Light source such as a point light source with directivity having an optical element having an inclined surface corresponding to the light flux from the light source continuously or in a density distribution that functionally increases in proportion to the distance from the light source. However, bright light can be obtained even with a light source having a directional distribution that is bright and has a linear shape, etc., and a continuous or continuous recess between the rows of optical elements that is finer than the optical elements or And / or a convex first light deflection element or / and a second light deflection element for slightly refracting part of light emitted by the optical element on the front surface or the back surface facing the optical element, and a white light source or the like And multiple columns The first optical deflector deflects a part of the light beam directed from the light source to the optical element by the first optical deflector to generate a spectrum of light appearing on the exit surface by a diffraction grating element or a Newton prism spectral element by a continuous or continuous optical element. Prevents the generation of spectrum by diffusing, and light and dark fringes generated by a constant exit angle due to interference of light rays caused by repeated total reflection by the front surface and the back surface are slightly disturbed by the second light deflection element. This prevents the occurrence of bright and dark stripes without lowering the emission brightness, and at the same time, the second light deflecting element and the convex first light deflecting element provided on the front surface portion and the rear surface portion provide a reflector or a sheet in the vicinity. The present invention relates to a light guide plate and a flat lighting device capable of preventing close contact with the like.

[0002]

2. Description of the Related Art A conventional light guide plate and flat lighting device use a method of utilizing scattering on the back surface of the light guide plate. In this method, more dots are printed in a circular or rectangular shape with increasing distance from the light source using ink mixed with a white material such as titanium oxide. It is trying to obtain uniformity of emitted light. Further, it is known to use an injection molding method, in which scattering is used on the front surface portion and the back surface portion of the light guide plate to randomly form a fine uneven shape.

Similarly, as a light guide plate and a flat lighting device using an injection molding method, there is known a light guide plate using a method of utilizing refraction or reflection on the front surface portion or the back surface portion of the light guide plate.
In this method, the convex shape and the concave shape are formed so as to be distributed (gradation) more as the distance from the light source is increased, and the probability of refraction or reflection is increased as the distance from the light source is increased to make the light emitted from the light guide plate uniform. There is.

Further, as a light guide plate and a flat lighting device using an injection molding method, there is known a light guide plate using a method of utilizing refraction or reflection on the front surface or the back surface of the light guide plate. In this method, a prism shape is formed in parallel with the light source, and a light beam from the light source is refracted or reflected by the sides of the prism to be deflected to the emission surface or emitted from the emission surface.

Similarly, a method is known in which a prism shape is provided on the front surface or the back surface of the light guide plate in parallel with the light source.
In this method, the height and depth of the prism are set higher or deeper as the distance from the light source increases, and the more light rays from the light source are received as the distance from the light source increases, the more reflected light or refracted light is used, which is related to the distance from the light source. Instead, the emitted light is made uniform.

Further, particularly when the light source is mixed with a plurality of wavelengths such as a white light source, the light emitted from the emission surface is split into a visible spectrum and looks like a rainbow color. For this reason,
When a liquid crystal display device is mounted on these flat illumination devices, a problem as a color liquid crystal screen occurs when the dispersed light corresponds to RGB (red, green, blue) of the liquid crystal.

Furthermore, the regular light and dark of the emitted light causes a bright and dark stripe pattern on the emitting surface. For this reason, when the liquid crystal display device is mounted on these flat lighting devices, a gradation of brightness appears on the screen, making it difficult to see.

[0008]

The conventional light guide plate and planar illuminating device use a method of utilizing scattering on the back surface of the light guide plate. The ink is mixed with a white material such as titanium oxide to form a circle. I tried to print more dots in the shape or rectangular shape as the distance from the light source increased, and to obtain the scattered light as the distance from the light source increased so that the light emitted from the light guide plate could be made uniform. Is absorbed and the light is scattered, the light ray does not reach only the emission surface, and the absolute amount of emitted light is low, which causes a problem in brightness.

Further, in the method of randomly forming minute irregularities on the front surface and the back surface of the light guide plate by injection molding and scattering the light rays from the light source, there is no loss due to absorption of light, but there is no loss due to the above printing method. Similarly, the light is scattered and the light ray does not reach only the exit surface, the brightness of the exit light is low, and the uneven distribution is random, which causes problems such as uneven brightness.

Similarly, when a large number of convex shapes or concave shapes are distributed (gradation) with increasing distance from the light source,
Although it is improved compared to printing with ink or random shaping of fine uneven shapes, the directivity (luminance distribution) of light rays can be increased by simply increasing the probability of refraction or reflection as the distance from the light source increases. Since the shape of the light source is not supported, there is a problem that the light quantity, directivity and energy of the light source are not fully utilized and utilized.

Further, a prism shape is formed on the front surface and the back surface of the light guide plate in parallel with the light source, and the light beam from the light source is refracted or reflected by the side of the prism to be deflected to the emission surface or emitted from the emission surface. The method is valid when all conditions are the same for the ridge length of the prism (in the case of a simple ideal state), but in reality, it does not correspond to the directivity (luminance distribution) of the light source or the shape of the light source. Therefore, there is a problem that the light quantity, directivity, and energy of the light source are not fully utilized and utilized.

Similarly, a prism shape is provided parallel to the light source on the front surface and the back surface of the light guide plate, and the height and depth of the prism are increased or decreased as the distance from the light source increases, and the light rays from the light source increase as the distance from the light source increases. A method of receiving a large amount of reflected light and refracted light and making the emitted light uniform regardless of the distance from the light source is good as a method away from the light source, but the prism itself is actually Since the directivity (luminance distribution) of the light source and the shape of the light source are not supported, there is a problem that the light amount, directivity and energy of the light source are not fully utilized and utilized.

In any case, these conventional methods do not deal with the directivity of the light quantity of the light source, the energy distribution, the shape of the light source, etc., and these conventional methods are limited.

Further, particularly when the light source is mixed with a plurality of wavelengths such as a white light source, the light emitted from the emission surface is spectrally divided into a visible spectrum and appears as rainbow colors. Therefore, when the liquid crystal display device is mounted on these flat illumination devices, a problem as a color liquid crystal screen occurs when the dispersed light corresponds to RGB (red, green, blue) of the liquid crystal. In order to solve this problem, a scattering sheet or the like is placed above the light guide plate for the purpose of scattering the dispersed light, but it may scatter the outgoing light having directivity, or due to the absorption of light by the scattering sheet, etc. There is a problem in reducing the brightness.

Furthermore, a regular light and dark of the emitted light causes a bright and dark stripe pattern on the emitting surface, and when the liquid crystal display device is mounted on these flat illumination devices, the brightness of the screen varies. Appears and makes it hard to see. In order to solve this problem, a method of placing a diffusion sheet or the like above the light guide plate to make it difficult to see the bright and dark stripe patterns is used, but there is a problem that the brightness is lowered as a whole. Moreover, as the number of members such as the scattering sheet and the diffusion sheet increases, there are problems in the number of assembly steps and the cost of members.

Furthermore, a light guide plate of a method of performing dot printing using an ink in which a white material such as titanium oxide is mixed in the back surface or injection molding is used to randomly form fine concave shapes on the front surface or the back surface of the light guide plate. In the case of a light guide plate molded by
The light guide plate and the diffusion sheet or the like provided on the upper portion of the front surface portion or the reflector or the reflection case or the like on the lower portion of the rear surface portion adhere to each other.
Therefore, the position of refraction due to the air layer is displaced,
There is a problem that the effect of the diffusion sheet and the like is halved. In addition, in order to return the leaked light from the light guide plate to the light guide plate to the light reflector and the reflective case, the light reflector and the reflective case are colored in white, but the light and the light guide plate are closely attached to the light reflector. There is a problem that you can see the surface of () through the (white) light guide plate.

The present invention has been made in order to solve the above problems, and in comparison with the prior art, the light flux from the light source always corresponds to the position corresponding to the directivity of the light amount from the light source and the energy distribution. By providing an optical element with a continuous sloped surface, the total reflection or refraction is performed by the sloped surface of the optical element that is continuous or equivalent in continuity at the position where the brightness and energy from the light source are always the same. The same level of brightness and energy can be emitted, and the optical element density distribution is increased in proportion to the distance from the light source as the brightness and energy from the light source are attenuated. The first light deflector having a concave shape and / or a convex shape which is finer than the optical element and which is capable of emitting light with the same product of the output angle and the output angle and is continuous between the rows. By providing a white light source with a strong directivity and a plurality of rows of continuous optical elements, a diffraction grating-like element or a Newton prism spectroscopic element is used to generate a rainbow-like visible spectrum on the exit surface by light splitting. The first light deflection element can diffuse a part of the light beam from the light source toward the optical element to prevent the generation of spectrum (rainbow).

Further, a light ray incident on the light guide plate from the end portions of the front surface portion and the rear surface portion connected to the incident portion of the light guide plate repeats total reflection on the front surface portion and the rear surface portion and emits bright and dark light having different brightness due to interference. A second light deflecting element for slightly refracting a part of the reflected light is provided, and a part of the light beam reaching the emission surface has a large diameter with respect to the height (a part of a so-called arc having a large radius of curvature). When the light beam that reaches the optical deflector of the present invention and is emitted to the outside from the second optical deflector is emitted at different emission angles that are smaller than that of the flat surface portion, periodic light and dark of the emitted light is generated. Can be prevented.

Further, the convex first light deflecting element and the second light deflecting element provided on the front surface and the back surface of the light guide plate allow the diffusion sheet and the like provided on the upper surface of the light guide plate and the lower part of the back surface to be provided. It is possible to prevent the contact of a certain reflector or reflective case with the light guide plate, and to bring out the effect of the diffusion sheet, etc., or to make the surface of the reflector or reflective case invisible through the (white) light guide plate. An object is to provide a light plate and a flat lighting device.

[0020]

A light guide plate according to claim 1 of the present invention has a front surface portion and / or a back surface portion from a light source which has continuity at a position corresponding to a luminance distribution or a light energy distribution of the light source. An optical element having an inclined surface corresponding to the bundle of rays of light is applied to a density distribution that functionally increases in proportion to the distance from the light source, and a finer than the optical element is provided between rows of continuous optical elements. It is characterized in that a first light deflection element having a concave shape and / or a convex shape is provided.

The light guide plate according to claim 1 has a surface portion or /
And an optical element having a sloped surface corresponding to the light flux from the light source having continuity at the position corresponding to the brightness distribution or light energy distribution of the light source and increasing the function in proportion to the distance from the light source Applied to the density distribution to be continuous, and between the rows of continuous optical elements, a concave shape finer than the optical elements or /
Since the convex first light deflection element is provided, total reflection and refraction are always performed by the inclined surface of the optical element having the same continuity at the position where the brightness and energy from the light source are equal, and the same is provided on the emission surface side. Brightness and energy can be emitted.
Moreover, the optical element density distribution is increased in proportion to the distance from the light source as the brightness and energy from the light source are attenuated so that the product of the amount of light emitted at any position of the light guide plate and its solid angle are equal. can do. In addition, the first light is used to generate a spectrum (rainbow) of light that appears on the exit surface by a diffraction grating-like element or a Newton prism spectroscopic element by a white light source with strong directivity and a plurality of rows of continuous optical elements. The deflecting element can diffuse a part of the light beam from the light source to the optical element.

Further, by the convex first light deflection element provided on the front surface portion or the back surface portion of the light guide plate, a diffusion sheet or the like provided near the front surface portion or the back surface portion, or a reflector under the back surface portion, It is possible to prevent close contact between the case and the light guide plate.

Further, in the light guide plate according to the second aspect, the front surface portion and / or the back surface portion has the inclined surface corresponding to the light flux from the light source continuously at the position corresponding to the luminance distribution or the light energy distribution of the light source. The optical element is provided with a density distribution that increases functionally in proportion to the distance from the light source, and between the rows of continuous optical elements, a concave shape finer than the optical element or /
And a convex first light deflection element.

The light guide plate according to claim 2 has a surface portion or /
A density distribution in which an optical element having an inclined surface corresponding to the light flux from the light source continuously at a position corresponding to the luminance distribution or the light energy distribution of the light source and the back surface is functionally increased in proportion to the distance from the light source. Since the first optical deflection element having a concave shape and / or a convex shape, which is finer than the optical element, is provided between the continuous rows of optical elements, the position where the brightness and energy from the light source are always the same. Further, it is possible to continuously perform total reflection, refraction, etc. by the inclined surface of the same optical element, and emit the same brightness and energy to the emission surface side. Moreover, the optical element density distribution is increased in proportion to the distance from the light source as the brightness and energy from the light source are attenuated so that the product of the amount of light emitted at any position of the light guide plate and its solid angle are equal. can do. In addition, by controlling the length of the optical element and the interval between adjacent optical elements, which are continuous, the product of the amount of light emitted from the optical element and its solid angle is equal, but the optical element is damaged. Lower light energies can be obtained at higher locations than where there are optical elements. Further, the first light deflection is caused by the generation of the spectrum (rainbow) of the light appearing on the emission surface by the diffraction grating-like element or the Newton prism spectroscopic element by the white light source having a strong directivity and the plurality of rows of continuous optical elements. The element may diffuse a portion of the light beam from the light source to the optical element.

Further, by the convex first light deflection element provided on the front surface or the back surface of the light guide plate, a diffusion sheet or the like provided near the front surface or the back surface or a reflector under the back surface or It is possible to prevent close contact between the case and the light guide plate.

Further, in the light guide plate according to a third aspect, the first light deflection element is randomly provided on the front surface portion and / or the back surface portion so as to be closer to or closer to the incident portion and has a height of 1 μm.
It is characterized in that it has a polygonal cone shape with a maximum width in the range of 4 μm to 16 μm and an arc shape or a conical shape with a diameter in the range of 4 μm to 16 μm.

In the light guide plate according to a third aspect of the present invention, the first light deflection element is randomly provided on the front surface portion and / or the back surface portion so as to be closer or closer to the incident portion, and the height is 1 μm to 4 μm.
In the range, the maximum width is a polygonal cone shape having a range of 4 μm to 16 μm, or the diameter is a circular arc shape having a range of 4 μm to 16 μm, or a conical shape. The emitted light of the optical element can be controlled by the light beam deflected by the first light deflecting element without giving a large influence by the light deflecting element. Moreover, in the case where the white light source has a strong directivity or the brightness is high, a visible spectrum is generated due to the light spectrum due to the diffraction grating-like element by the continuous optical elements in a plurality of rows, particularly on the exit surface near the entrance. , The first light deflection element is provided so as to be closer to the entrance portion of the front surface portion and / or the back surface portion so as to diffuse a part of the light ray traveling from the light source to the optical element or emit a light ray having a different emission angle to the emission surface. You can

When the white light source has a weak directivity, the light rays entering the light guide plate from the end portions of the front surface portion and the rear surface portion connected to the incident portion of the light guide plate are totally reflected on the front surface portion and the rear surface portion. By randomly providing a first light deflection element on the front surface portion and / or the back surface portion, a part of the light beam that goes to the optical element is traced. Can be diffused into.

Further, in the light guide plate according to the fourth aspect, the front surface portion and / or the back surface portion has a continuity at a position corresponding to the luminance distribution or the light energy distribution of the light source and has an inclination corresponding to the light flux from the light source. An optical element having a surface is applied to a density distribution that functionally increases in proportion to the distance from the light source, and a part of the light emitted by the optical element having continuity on the front surface or the back surface facing the optical element is It is characterized in that a second light deflecting element for slightly refracting is provided.

The light guide plate according to claim 4 is a surface portion or /
And an optical element having a sloped surface corresponding to the light flux from the light source having continuity at the position corresponding to the brightness distribution or light energy distribution of the light source and increasing the function in proportion to the distance from the light source Since a second light deflector is provided on the front surface or the back surface facing the optical element to slightly refract a part of the light emitted by the optical element having continuity, the brightness from the light source is always provided. It is possible to perform total reflection, refraction, etc. at the positions where the energy is equal to each other by the inclined surface of the optical element having the same continuity, and to emit the same brightness and energy to the emission surface side. Moreover, the optical element density distribution is increased in proportion to the distance from the light source as the brightness and energy from the light source are attenuated so that the product of the amount of light emitted at any position of the light guide plate and its solid angle are equal. can do. In addition, the light rays that have entered the light guide plate from the ends of the front surface portion and the back surface portion that are connected to the incident portion of the light guide plate undergo total reflection repeatedly on the front surface portion and the back surface portion, and the brightness reaches the emission surface due to interference A part of light / dark light rays having periodicity or the like reaches a second light deflection element having a large diameter (so-called a part of an arc having a large radius of curvature) with respect to height, and this second light deflection element When the light is emitted from the outside to the outside, the light is emitted at a different emission angle that is smaller than that of the flat surface portion, and it is possible to disturb a part of the light and dark rays having a periodicity or destroy the light and dark.

Further, the second light deflection element provided on the front surface portion or the back surface portion of the light guide plate can prevent the diffusion sheet or the like provided near the front surface portion or the back surface portion from being in close contact with the light guide plate.

Further, in the light guide plate according to the fifth aspect, the front surface portion and / or the back surface portion has the inclined surface corresponding to the light flux from the light source continuously at the position corresponding to the luminance distribution or the light energy distribution of the light source. The optical element is given a density distribution that increases functionally in proportion to the distance from the light source, and a part of the light emitted by the optical element continuously provided on the front surface or the back surface facing the optical element is slightly refracted. A second light deflection element is provided.

The light guide plate according to claim 5 is a surface portion or /
A density distribution in which an optical element having an inclined surface corresponding to the light flux from the light source continuously at a position corresponding to the luminance distribution or the light energy distribution of the light source and the back surface is functionally increased in proportion to the distance from the light source. Since the second light deflecting element for slightly refracting a part of the light emitted by the optical element continuously provided on the front surface portion or the rear surface portion facing the optical element is provided, the brightness and energy from the light source are always maintained. It is possible to continuously perform total reflection, refraction, etc. at the same position by the inclined surface of the same optical element, and to emit the same brightness and energy to the emission surface side. Moreover, the optical element density distribution is increased in proportion to the distance from the light source as the brightness and energy from the light source are attenuated so that the product of the amount of light emitted at any position of the light guide plate and its solid angle are equal. can do. In addition, by controlling the lengths of the optical elements and the intervals between adjacent optical elements, which are continuous, the product of the amount of light emitted from the optical elements and the solid angle can be emitted equally. In addition, the light entering the light guide plate from the ends of the front surface and the back surface connected to the incident part of the light guide plate undergoes total reflection repeatedly on the front surface and the back surface, and reaches the emission surface by interference. A part of the light / dark light beam having the property of reaching the second light deflection element having a large diameter with respect to the height (a part of a so-called arc having a large radius of curvature),
Light rays emitted from the second light deflecting element to the outside may be emitted at different emission angles that are smaller than those of a flat surface portion, and may disturb or disrupt part of the light rays of periodic light and dark rays. You can

Further, the second light deflecting element provided on the front surface portion or the back surface portion of the light guide plate can prevent the diffusion sheet or the like provided near the front surface portion or the back surface portion from being in close contact with the light guide plate.

According to a sixth aspect of the present invention, in the light guide plate, the diameter of the second light deflection element is an arc shape in the range of 5 μm to 100 μm, and the height is in the range of 1/20 to 1/80 of the diameter, and the surface thereof is It is characterized in that more portions are provided at random or closer to the incident portion on the back surface portion.

In the light guide plate according to the sixth aspect, the diameter of the second light deflection element is an arc shape in the range of 5 μm to 100 μm and the height is in the range of 1/20 to 1/80 of the diameter. On the other hand, since the diameter is large (so-called a part of a circular arc having a large radius of curvature), the normal line of the second light deflection element has a small difference from the normal line of the light guide plate.

Further, since the second light deflection elements are provided on the front surface portion or the rear surface portion more randomly or closer to the incident portion, the end portions of the front surface portion and the rear surface portion connected to the incident portion of the light guide plate are introduced into the light guide plate. The incident light ray is repeatedly totally reflected on the front surface and the back surface to generate bright and dark light with different brightness due to interference. In the vicinity of the incident portion of the light guide plate having particularly high luminance, the bright and dark fringe pattern is more noticeable than in other places, and thus the second light deflecting element is provided so as to be closer to the incident portion of the front surface portion or the back surface portion. As a result, it is possible to prevent the occurrence of distinct bright and dark stripes.

Further, the light guide plate according to claim 7 is characterized in that the optical element has a triangular, trapezoidal, or arcuate cross section and is continuous or discontinuous.

In the light guide plate according to the seventh aspect, since the optical element has a triangular shape, a trapezoidal shape, an arc shape and is continuous or discontinuous, a light beam entering the light guide plate from the incident portion of the light guide plate is generated. Triangular, trapezoidal and arcuate inclined surfaces can be present at positions corresponding to the bundle of rays from the light source, and when these are continuous, the same brightness and energy can be emitted at any position, Even if it is discontinuous, the same brightness and energy can be continuously emitted at any position.

Further, in the light guide plate according to the eighth aspect, the height of the optical element is increased as the optical element is moved away from the light source or /
It is also characterized in that the height is partially increased.

In the light guide plate according to the eighth aspect, since the height of the optical element is increased or / and the height is partially increased as the optical element is farther from the light source, the optical element far from the light source receives the light ray from the light source. The amount of light emitted from the light guide plate and the angle of light emitted from the light guide plate can be changed by total reflection or by partially increasing or decreasing the height.

Further, the light guide plate according to claim 9 is characterized in that the angle formed by the inclined surface with the front surface portion and the back surface portion is in the range of π / 2-2 critical angle to critical angle.

In the light guide plate according to the ninth aspect, the angle formed by the inclined surface with the front surface portion and the back surface portion is in the range of π / 2−2 critical angle to the critical angle. By using the range from the incident angle to the minimum angle that violates the critical angle, all the totally reflected light can violate the critical angle.

Further, the light guide plate according to the tenth aspect is characterized in that the angle formed by the front surface portion and the back surface portion of the inclined surface is close to the critical angle in proportion to the distance from the light source.

In the light guide plate according to the tenth aspect, since the angle formed by the inclined surface with the front surface portion and the back surface portion approaches the critical angle in proportion to the distance from the light source, even if the brightness and energy from the light source are attenuated. The reflected light totally reflected in proportion to the distance from the light source is emitted at a small emission angle. For this reason, the product of the amount of light emitted and the solid angle thereof can be equally emitted at any position on the emission surface of the light guide plate.

Further, in the light guide plate according to the eleventh aspect, the inclined surface is formed with an arc inside or outside with the center of the inclined surface as a center, or with an arc partially inside and outside the inclined surface. It is characterized by being

In the light guide plate according to the eleventh aspect, since the inclined surface forms an arc inside or outside with the center of the inclined surface as a center, or partially inside and outside the inclined surface forms an arc. When the emission position in the light guide plate having the same size is an arc inside the inclined surface, it can be brought closer to the light source side. When the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be condensed.

Further, the emission position in the light guide plate of the same size can be moved away from the light source side when the outside of the inclined surface is an arc. When the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be diffused. Furthermore, by partially forming an arc on the inner side and the outer side on one inclined surface, it is possible to obtain different actions such as light collection and diffusion on one inclined surface.

A flat lighting device according to a twelfth aspect of the present invention is
The light source, the incident part for guiding the light from the light source, and the position having the continuity at the position corresponding to the brightness distribution or the light energy distribution of the light source and having the inclined surface corresponding to the light flux from the light source, the distance from the light source. An optical element provided with a density distribution that increases proportionally and functionally, and a concave shape and / or a convex shape finer than the optical element between the continuous optical element rows.
Light deflecting element or / and a light guide plate having a second light deflecting element for minutely refracting part of the light emitted by the optical element on the front surface or the back surface facing the optical element, and the incident portion of the light guide plate. And a reflector that covers the area other than the emission surface and reflects the light leaked from the light guide plate back into the light guide plate.

A flat illumination device according to a twelfth aspect of the invention has a light source, an entrance portion for guiding light from the light source, continuity at a position corresponding to a luminance distribution or a light energy distribution of the light source, and a light flux from the light source. An optical element having a corresponding inclined surface and having a density distribution that increases functionally in proportion to the distance from the light source, and a concave that is finer than the optical element between rows of continuous optical elements. A first or second convex light-deflecting element or / and a second light-deflecting element for slightly refracting part of the light emitted by the optical element is provided on the front surface or the back surface facing the optical element. Since it has a light guide plate and a reflector that covers the light guide plate except for the incident part and the emission surface and reflects the leaked light from the light guide plate back into the light guide plate, continuity is always maintained at a position where the brightness and energy from the light source are equal. On the inclined surface of an optical element equivalent to Perform total reflection and refraction, etc. I, can emit the same brightness and energy on the exit surface side.
In addition, the density distribution of the optical element increases functionally in proportion to the distance from the light source with the attenuation of the brightness and energy from the light source, and the amount of light emitted at any position of the light guide plate and its solid angle It is possible to control the output angle from the output surface by setting the angles of the inclined surfaces so that the output is the same.

Further, firstly, the generation of a spectrum (rainbow) of light appearing on the exit surface by a diffraction grating element or a Newton prism spectroscopic element by a white light source having a strong directivity and a plurality of rows of continuous optical elements is first generated. Part of the light beam from the light source to the optical element can be diffused by the light deflection element of, and the light beam entering the light guide plate from the ends of the front surface part and the back surface part connected to the incident part of the light guide plate is Total reflection is repeated on the back surface, and a part of the light and dark rays having periodicity with different brightness, etc. that reach the emission surface by interference have a large diameter with respect to the height (so-called an arc with a large radius of curvature). Light) when it reaches the second light deflector and is emitted from the second light deflector to the outside at a different emission angle that is smaller than that of the flat surface portion, and the light and dark light with periodicity is emitted. Disturb or brighten some of the rays It is possible to break the.

The convex first light deflecting element and the second light deflecting element provided on the front surface and the back surface of the light guide plate are used to form a diffusion sheet and the like on the front surface and the back surface, and the back surface. It is possible to prevent contact between the light guide plate and a reflector or a reflection case under the light to be emitted.

Further, in the flat illumination device according to the thirteenth aspect, the light source, the incident portion for guiding the light from the light source, and the light flux from the light source are continuously arranged at positions corresponding to the luminance distribution or the light energy distribution of the light source. An optical element having a corresponding inclined surface and having a density distribution that increases functionally in proportion to the distance from the light source, and a concave that is finer than the optical element between successive rows of optical elements. A first or second convex light-deflecting element or / and a second light-deflecting element for slightly refracting part of the light emitted by the optical element is provided on the front surface or the back surface facing the optical element. It is characterized by comprising a light guide plate and a reflector that covers the light guide plate except for the incident portion and the emission surface thereof and reflects the leaked light from the light guide plate back into the light guide plate.

In the flat illumination device according to the thirteenth aspect, the light source, the incident portion for guiding the light from the light source, and the light flux from the light source continuously correspond to the position corresponding to the luminance distribution or the light energy distribution of the light source. An optical element having an inclined surface and having a density distribution that functionally increases in proportion to the distance from the light source, and a concave shape finer than the optical element or between the rows of continuous optical elements. A light guide plate having a convex first light deflector or / and a second light deflector for slightly refracting part of the light emitted by the optical element on the front surface or the back surface facing the optical element. And a reflector that covers the light guide plate other than the incident part and the emission surface and reflects the leaked light from the light guide plate back into the light guide plate, so that the brightness and energy from the light source are always equal to each other. Due to the inclined surface of various optical elements, Performs folding or the like, it is possible to emit the same brightness and energy on the exit surface side. Moreover, the product of the amount of light emitted and the solid angle thereof is equal at any position of the light guide plate by increasing the density distribution of the optical element in proportion to the distance from the light source as the brightness and energy from the light source are attenuated. It is possible to continuously emit light or to change the emission angle from the emission surface and the optical element itself by setting the angle of the inclined surface.

Further, the first generation of light spectrum (rainbow) appearing on the exit surface by a diffraction grating element or a Newton prism spectroscopic element by a white light source having a strong directivity and a plurality of rows of continuous optical elements is first described. Part of the light beam from the light source to the optical element can be diffused by the light deflection element of, and the light beam entering the light guide plate from the ends of the front surface part and the back surface part connected to the incident part of the light guide plate is Total reflection is repeated on the back surface, and a part of the light and dark rays having periodicity with different brightness, etc. that reach the emission surface by interference have a large diameter with respect to the height (so-called an arc with a large radius of curvature). Light) when it reaches the second light deflector and is emitted from the second light deflector to the outside at a different emission angle that is smaller than that of the flat surface portion, and the light and dark light with periodicity is emitted. Disturb or brighten some of the rays It is possible to break the.

The convex first light deflecting element and the second light deflecting element provided on the front surface and the back surface of the light guide plate are used to form a diffusion sheet and the like on the front surface and the back surface, and the back surface. It is possible to prevent contact between the light guide plate and a reflector or a reflection case under the light to be emitted.

Further, the flat illumination device according to the fourteenth aspect is characterized in that the light source is a white light source having a directivity or / and a directivity distribution.

In the flat illumination device according to the fourteenth aspect, since the light source is a white light source having a directivity or / and a directivity distribution, when the distances from the incident part of the light guide plate are not equal, the direction is far from the incident part. The directivity can be matched.

[0059]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention provides an optical element having a continuous surface and an inclined surface corresponding to a light flux from the light source continuously at a position corresponding to the luminance distribution or the light energy distribution of the light source on the front surface portion or the back surface portion from the light source. A first light deflection element having a concave shape or a convex shape finer than that of the optical element is provided between the rows of continuous and continuous optical elements having a density distribution that functionally increases in proportion to Alternatively, the light rays that enter the light guide plate from the ends of the front surface and the back surface that are connected to the incident part of the light guide plate undergo total reflection on the front surface and the back surface repeatedly and reach the emission surface by interference. The second light deflection element that slightly refracts a part of the light and dark light rays that have the property of preventing the occurrence of the visible spectrum (rainbow) and the stripe pattern of the light and dark light due to the optical element, etc. The light guide plate that made it possible to obtain There is provided a fine flat illumination device.

FIG. 1 is a schematic exploded view of a flat lighting device according to the present invention, and FIGS. 2 to 13 are schematic diagrams of a light guide plate according to the present invention.
FIG. 14 is a partially enlarged view of the light guide plate of FIG. 10, and FIGS.
7 is a schematic trajectory diagram of light rays of a light guide plate according to the present invention, FIGS. 18 to 20 are schematic trajectory diagrams of light rays of a light guide plate according to the present invention, FIG.
3 is a schematic view of a light guide plate according to the present invention. 1 to 14, the extremely small first light deflection element 30 and the second light deflection element 30
The light deflection element 40 is exaggerated in a part of the light guide plate 2.

As shown in FIG. 1, the flat lighting device 1 includes a light guide plate 2, a light source 3, a reflector 14 and a reflection case 15.
It is roughly composed of

The light guide plate 2 is formed of a transparent acrylic resin (PMMA), polycarbonate (PC) or the like having a refractive index of about 1.4 to 1.7. The light guide plate 2 has a side surface portion 11
And a front surface portion 8 for emitting light, a rear surface portion 9 located on the opposite side, and an incident portion 7 for guiding light from the light source 3.

As shown in FIGS. 2 to 9, the light guide plate 2 has the surface 8 or the optical element 20 having continuous continuity with respect to the position corresponding to the luminance distribution or the light energy distribution of the light source 3. It can be configured to be applied to the / and the back surface portion 9.

Further, as shown in FIGS. 10 to 13, the light guide plate 2 has the optical element 20 ′ continuously arranged at predetermined intervals with respect to the position corresponding to the luminance distribution or the light energy distribution of the light source 3 on the surface portion 8. Alternatively, and / or the back surface portion 9 may be provided.

Further, the light guide plate 2 has a concave shape or / or finer than the optical elements 20 between the rows of continuous or continuous optical elements 20 on the front surface portion 8 and / or the back surface portion 9.
The convex first light deflection element 30 may be provided. In the example of FIG. 1, the rear surface portion 9 is provided with a first optical deflection element 30 having a concave shape and / or a convex shape, which is finer than the optical elements 20, between the rows of continuous optical elements 20. I am trying.

Further, in the light guide plate 2, the light rays that have entered the light guide plate 2 from the end portions 7 ′ of the front surface portion 8 and the rear surface portion 9 connected to the incident portion 7 of the light guide plate 2 are incident on the front surface portion 8 or the rear surface portion 9. A configuration is provided in which a second light deflecting element 40 is provided that slightly refracts a part of light rays of light and dark light having periodicity with different brightness, etc. that reach the emission surface by interference by repeating total reflection on the front surface portion 8 and the rear surface portion 9. Can be In the example of FIG. 1, the second light deflection element 40 is provided on the surface portion 8.

Here, FIG. 14 is a partially enlarged view of the optical element 20 'provided continuously on the front surface portion 8 and the rear surface portion 9 of the light guide plate 2 at the predetermined intervals shown in FIG.

As shown in FIG. 14, the length of the optical element 20 'is shortened to, for example, 20'a to reduce the amount of total reflection on the inclined surface, or 20'b to be increased. Increase the amount of total reflection on the inclined surface. Thereby, the amount of total reflection from the optical element 20 'can be controlled.

The distance between the adjacent optical elements 20 'is controlled. For example, the interval is lengthened as 21a, or the interval is shortened as 21b. As a result, the product of the amount of light emitted from the optical element 20 ′ and the solid angle thereof is equal, but the portion where the optical element 20 ′ is lost (interval 21a
And 20b) has a lower light energy than the optical element 20 '. As a result, a desired luminance distribution can be expressed on the light guide plate 2.

Further, as the light guide plate 2 is farther from the light source 3, the brightness and energy from the light source 3 are attenuated. For this reason,
The number of optical elements 20 is increased as the distance from the incident portion 7 increases. The optical element 20 provided on the front surface portion 8 and / or the back surface portion 9 is made to have a density distribution that increases exponentially in proportion to the distance from the light source 3. As a result, the product of the unit area of the optical element 20 near the incident portion 7 and the strong light intensity and the product of the unit area of the optical element 20 near the reflection end face portion 10 away from the incident portion 7 and the weak light intensity. Are equal.

In addition, the light guide plate 2 includes the optical element 20 and the light source 3
The cross section has a triangular shape, a trapezoidal shape, or an arc shape so as to have an inclined surface corresponding to the light flux from the. As a result, the light rays from the light source 3 are efficiently totally reflected by the inclined surface without loss.

Further, although not shown, the light guide plate 2 increases the height of the optical element 20 as the optical element 20 moves away from the light source 3. Thereby, the height of the inclined surface portion can be increased, and the area of the inclined surface portion can be increased. As a result, even in the optical element 20 far from the light source 3, the light source 3
You can receive many rays from. Then, the received light beam is totally reflected by the inclined surface and the light beam is deflected in the direction of the emitting surface, so that a large amount of the emitted light can be emitted even at a position far from the light source 3, and the light can be uniformly guided regardless of the distance of the light source 3. The emission brightness from the optical plate 2 can be obtained.

In the light guide plate 2, although not shown, the height of the inclined surface portion can be increased or decreased by partially increasing or decreasing the height of the optical element 20. Thereby, the area of the inclined surface portion can be increased or decreased.
As a result, the amount of light emitted from an arbitrary position of the light guide plate 2 can be increased or decreased, and the angle of emission of the light guide plate from an arbitrary position can be changed. As a result, it is possible to control the brightness and the viewing angle of the desired position of the light guide plate 2.

By partially increasing the height of the optical element 20, the optical element 20 having, for example, a triangular cross section is formed.
In this case, the height of the edge of one continuous triangle can be continuously changed, and the change of the emitted light can be made continuous.

Further, the angle formed by the inclined surface of the optical element 20 with the front surface portion 8 and the back surface portion 9 is in the range of π / 2−2 critical angle γ to critical angle γ. That is, the angle formed by the front surface portion 8 and the back surface portion 9 becomes closer to the critical angle γ as the inclined surface is further away from the light source 3 in proportion to the distance from the light source 3.

Here, when the light from the light source 3 is guided from the incident portion 7 into the inside of the light guide plate 2, for example, when the material of the light guide plate 2 is polycarbonate (PC) resin, the refractive index n = 1. Therefore, the light ray L0 existing in the light guide plate 2 after entering the light guide plate 2 from the air layer is 0 ≦ |
According to the formula α | ≦ sin ⁻¹ (1 / n) (where n in the formula is
Is an air layer, and the refractive index n = 1) is approximately the refraction angle α = ± 38.9
It is within the range of 713 °.

Light incident on the light guide plate 2 within the range of the refraction angle α = ± 38.9713 ° is sin γ = (at the interface between the light guide plate 2 and the air layer (refractive index n = 1). 1 /
The critical angle can be expressed by the equation n). For example, since the refractive index of a polycarbonate resin, which is a resin material used for a general light guide plate 2, is about n = 1.59,
The critical angle γ is about γ = 38.97 °. Further, in the case of a light guide plate using an acrylic resin (PMMA) material, the refractive index n of the acrylic resin is about n = 1.49 and the refraction angle α is about α = ± 42.38 °. The critical angle γ is also about γ = 42.38 °.

For example, the refractive index n of the light guide plate 2 made of acrylic resin is about n = 1.49, and in the example of FIG. 20, the refraction angle α of the light beam entering the light guide plate 2 is α = 42.38.
It will be about °. Therefore, in the optical element 20 provided on the back surface portion 9 of the light guide plate 2, the angle θ formed with the back surface portion 9 is (π / 2-2 ·
(From 42.38 °) Within the range of 5.24 ° to 42.38 °, the angle θ1 that is the minimum value in the vicinity of the entrance 7 is 5.2.
An inclined surface 21 of 4 ° is provided, and an inclined surface 22 having an angle θ2 = 42.38 °, which is the maximum value, is provided at a position away from the incident portion 7.

Of the light rays guided into the light guide plate 2 having the above structure, the light ray L having an incident angle β = 42 °, which is often near the incident portion 7, is included.
1 is the inclined surface 21 of the optical element 20 (inclination θ1 = 5.24).
Total reflection at (°). The totally reflected light ray L11 travels in the direction of the surface portion 8 of the light guide plate 2, and here (incident angle is about 36 °).
The light ray L11 breaks the critical angle γ and goes out of the surface portion 8 (emission angle 6
It is emitted as the emitted light L12.

As described above, among the light rays that have entered the light guide plate 2, the light rays having a small refraction angle are other than the light rays that have traveled in the extension direction of the light guide plate 2 (the reflection end surface portion 10 opposite to the incident portion 7). There are many light rays having a large incident angle in the vicinity of the incident portion. Therefore, the inclined surface 21 of the optical element 20 provided in the vicinity of the incident portion is inclined even with a light ray having a large incident angle by setting the angle formed with the back surface portion 9 to be about 90 ° minus the value obtained by multiplying the critical angle γ by two. The light can be totally reflected by the surface 21, travels in the direction of the surface portion 8, breaks the critical angle γ of the light guide plate 2, and is emitted from the surface portion 8.

In addition, among the light rays guided into the light guide plate 2, the incident angle β = 2 ° of the light rays that largely advance in the direction away from the incident portion 7.
The light ray L2 of a degree is the inclined surface 22 (the inclination degree θ
Total reflection at 1 = 42.38 °). This totally reflected light ray L21 travels in the direction of the surface portion 8 of the light guide plate 2, where the light ray L21 violates the critical angle γ (incidence angle of about 1.5 °) and the surface portion 8 thereof.
(Emission angle of about 2.24 °) as emission light L22.

As described above, among the light rays that have entered the light guide plate 2, the light rays having a small refraction angle travel in the extension direction of the light guide plate 2 (the direction opposite to the incident portion 7), and the optics provided near the incident portion 7 are provided. The probability of colliding with the element 20 is low. Therefore, the inclined surface 22 of the optical element 20 provided at a position distant from the incident portion 7 is set so that the angle formed with the back surface portion 9 is approximately equal to the critical angle γ, so that light rays with a small incident angle are totally reflected by the inclined surface 22. And then the surface part 8
The light can be emitted from the surface portion 8 while proceeding in the direction and breaking the critical angle γ of the light guide plate 2.

Therefore, as can be understood from the description of the extreme cases as described above, in the light guide plate of this example, the light rays from the incident portion 7 are separated from the inclined surface of the optical element 20 as the distance from the incident portion 7 increases. The rear surface 9 is proportional to the distance from the light source 3 so that the inclination angle gradually changes from the inclined surface 21 to the inclined surface 22.
The angle formed by is close to the critical angle γ. As a result, the product of the amount of light emitted and the solid angle thereof is equal at any position on the emission surface of the light guide plate 2 by the optical element 20 corresponding to the distance from the light source 3 even with the brightness and energy attenuation from the light source 3. Can be emitted.

Although the optical element 20 in which the back surface 9 is provided with the inclined surface has been described here, as described above, the light ray incident from the incident portion 7 has a refraction angle α in the case of acrylic resin, for example. α = ± 42.38 °, and in the case of polycarbonate resin, the refraction angle α is α = ± 38.9713 °
Since it advances in the direction of the front surface portion 8 and the direction of the back surface portion 9 when the optical element 20 is provided on the front surface portion 8 and the same configuration as described above is obtained, a light guide plate 2 for use in a front light can be obtained. . Further, the emitted light can be freely controlled by selecting the angle of the inclined surface of the optical element 20 so that the light beam once totally reflected on the front surface portion 8 is totally reflected again on the rear surface portion 9.

Further, by making a circular arc inward or outward centering on the central portion of the inclined surface 21 or the inclined surface 22 of the optical element 20, the emission position within the light guide plate 2 of the same size can be adjusted. When the inside of the inclined surface 22 is formed into an arc, it can be brought closer to the light source side, and when the outside of the inclined surface 21 or the inclined surface 22 is formed into an arc, it can be moved away from the light source side.

When the outside of the inclined surface 21 or the inclined surface 22 is an arc, when the light source 3 or the light source 4 is close, the totally reflected light becomes parallel light, and when the light source 3 or the light source 4 is far. Can diffuse the totally reflected light.

Further, when the inside of the inclined surface 21 or the inclined surface 22 is an arc, when the light source 3 or the light source 4 is near, the totally reflected light becomes parallel light, and when the light source 3 or the light source 4 is far away. Can collect the totally reflected light.

Further, two arcs different from the inside and the outside are provided on the inclined surface 21 or the inclined surface 22 of the optical element 20 in one inclined surface, and for example, the front surface portion 8 or the back surface portion of the inclined surface 21 or the inclined surface 22 is provided. By forming an inner circular arc near 9 and an outer circular arc far from the front surface portion 8 and the back surface portion 9, two inclined light converging and diffusing functions can be partially achieved by one inclined surface. Obtainable.

As shown in FIG. 2 (similar to FIG. 1), the optical element 20 has a luminance near the electrode of the CCFL (cold shadow tube) when the light source 3 is linear such as CCFL (cold shadow tube). Is lower than the others, the luminance distribution is uniform except for both ends and attenuated at both ends. Therefore, the distribution corresponds to this. That is,
The optical elements 20 at both ends are extremely close to the incident portion 7, and the optical elements 20 are closer to the reflection end face portion 10 facing the incident portion 7.
Of the side surfaces 11 at both ends by providing a fine pitch.
Then it is particularly densely distributed. It should be noted that FIG. 10 shows an optical element 20 ′ that is a discontinuous separation of the continuous optical element 20 of FIG. 2 and is continuously distributed.

The optical element 20, as shown in FIG.
When b is in the shape of an L (L-shaped) such as CCFL (cold cathode), the brightness near the electrodes of CCFL (cold cathode) is attenuated lower than the other, and the two light sources 3b of the light guide plate 2 near the light source 3b are attenuated. The brightness distribution is highest near the edge 60 where the side surfaces 11 intersect, and this edge 6
Since the luminance distribution near the diagonal line connecting the diagonal 6a with 0 has a higher luminance distribution than that near the side surfaces 11, the distribution corresponds to this. That is, the optical elements 20 near both ends of the light source 3b are extremely close to the incident portion 7, and the pitch of the optical elements 20 near the diagonal line connecting the diagonal 6a from the vicinity of the end 60 where the two side surfaces 11 of the light guide plate 2 intersect is rough. It is provided in such a manner that it is particularly densely distributed in the vicinity of the end portion 6 facing the incident portion 7. In FIG. 13, the optical elements 20 ′ obtained by discontinuously separating the continuous optical elements 20 of FIG. 3 are continuously distributed.

The optical element 20, as shown in FIG.
In the case of a point light source such as a semiconductor light emitting element (LED), the center of the semiconductor light emitting element has a particularly high brightness and the portions other than the center are attenuated, so the distributions correspond to these. That is, the direction having a strong luminance distribution is set to the direction of the diagonal 6a of the incident portion 5 of the light guide plate 2, and the optical element 2 approaches the diagonal 6a.
The pitch of 0 is finely provided, and the end portion 6 has finer pitch and distribution than the diagonal. In addition, FIG. 11 shows an optical element 20 ′ in which the continuous optical element 20 of FIG. 4 is discontinuously separated.
Are continuously distributed.

The optical element 20, as shown in FIG.
Is a point light source such as a semiconductor light emitting element (LED), since the light source 4 is a semiconductor light emitting element, the center of the semiconductor light emitting element has a particularly high brightness and the portions other than the center are attenuated. It has a corresponding distribution. That is, the (radial) incident part 5 is provided on one side surface of the light guide plate 2, the direction of strong luminance distribution is set to the side surface direction facing the light guide plate 2, and the optical element 20 is arranged in both end directions of the light sources 4 (of the two light sources 4). (Including the gap), and the pitch and distribution are finely provided as the end 6 is approached. Note that in FIG. 12, optical elements 20 ′ obtained by discontinuously separating the continuous optical elements 20 of FIG. 5 are continuously distributed.

The optical element 20, as shown in FIG.
When b is an array shape in which a plurality of dot-shaped objects such as semiconductor light emitting elements (LEDs) are arranged, since the light source 4b is a semiconductor light emitting element, the center of the semiconductor light emitting element is particularly high in brightness, and the other portions are attenuated. Therefore, the distributions correspond to these. That is, the incident portion 5 is provided on one side surface side of the light guide plate 2, the direction of strong luminance distribution is the reflection end surface portion 10 in the opposite direction of the incident portion 5 of the light guide plate 2, and the optical element 20 is provided between the light sources 4b adjacent to each other. Is closer to the incident portion 5, and the pitch and distribution are finer as they approach the reflection end face portion 10, and the pitch and distribution are finer as they approach the center between the light sources 4b adjacent to each other.

The optical element 20, as shown in FIG.
Is a point light source such as a semiconductor light emitting device (LED),
Since the light source 4 is a semiconductor light emitting element, the brightness of the center of the semiconductor light emitting element is particularly high, and the light is attenuated except at the center.
The distribution corresponds to these. That is, the incident portions 5 are provided at the four corners of the light guide plate 2, and the direction in which the luminance distribution is strong is set to the central direction of the light guide plate 2, and the optical elements 20 are arranged between the light sources 4 adjacent to each other and the pitch and the distribution are closer to the central direction. Are provided in detail.

The optical element 20, as shown in FIG.
Is a point light source such as a semiconductor light emitting device (LED),
Since the light source 4 is a semiconductor light emitting element, the brightness of the center of the semiconductor light emitting element is particularly high, and the light is attenuated except at the center.
The distribution corresponds to these. That is, the circular (or polygonal) incident portion 5 is provided at the center of the light guide plate 2, and the direction in which the luminance distribution is strong is the four end portions 6 of the light guide plate 2.
An optical element 20 is provided so that a portion having low luminance approaches the incident portion 5, a position where luminance is equal becomes a completely continuous circumference, and the pitch and distribution become finer as approaching the outer peripheral direction of the light guide plate 2.

The optical element 20, as shown in FIG.
Is a point light source such as a semiconductor light emitting device (LED),
Since the light source 4 is a semiconductor light emitting element, the brightness of the center of the semiconductor light emitting element is particularly high, and the light is attenuated except at the center.
The distribution corresponds to these. That is, the light guide plate 2 is provided with a substantially elliptical entrance portion 5 in the lower center direction, and the direction having a strong luminance distribution is set to the two upper end portions 6 direction of the light guide plate 2 and one center lower portion, and the low luminance portion is incident. The optical element 20 is provided so that the position closer to the portion 5 and having the same brightness and the like becomes a completely continuous circumference, and the pitch and distribution become finer as approaching both ends 6b in the downward direction and the outer peripheral direction of the light guide plate 2. .

Although not shown here, the light source 3 is C
Even in the case of a U (U) shape such as a CFL (cold cathode ray tube), the brightness in the vicinity of the light source 3 is also low, and only one side surface portion 11 of the light guide plate 2 without the light source 3 has the lowest brightness. As a distribution corresponding to these, the optical element 20 is made denser as it approaches the middle of the electrode of the light source 3 from the vicinity of the electrode of the light source 3, and the optical element 2 is arranged at the opposite position of the bottom of the U shape.
0 is densely set.

The surface portion 8 shown in FIGS.
Or / and the light source 3, the light source 4, and the light source 4 on the back surface portion 9.
The optical element 20 'has a density distribution that is functionally increased in proportion to the distance from the light source 3 or the light source 4 at positions corresponding to the luminance distribution or the light energy distribution of b, but is provided continuously. The length of the element 20 'is increased or decreased according to the amount of light from the light source 3 or the light source 4 to control the amount of total reflection on the front surface 8 or the back surface 9 to control the amount of light emitted from the emission surface. be able to.

The optical element 20 has a triangular, trapezoidal, or arcuate cross section, and is, for example, 4 μm to 10 μm.
It can be configured by forming a continuous concave shape or a convex shape that ends at the end of the light guide plate 2 having a base width of about 0 μmm.

Similarly, the optical element 20 has a triangular, trapezoidal, or arcuate cross section, and is, for example, 4 μm to 1 μm.
It has a concave shape or a convex shape having a bottom width of about 00 μmm, and is continuously formed on the front surface portion 8 and the rear surface portion 9 of the light guide plate 2 at positions corresponding to the brightness and light energy distribution of the light sources 3 and 4 and the like. It can be configured to be provided.

As described above, by providing the optical elements 20 and 20 'continuously or discontinuously on the front surface 8 and the back surface 9 of the light guide plate 2, the inclined surfaces of the optical elements 20 and 20' cause the light sources 3, 3b ,. It is possible to totally reflect the light rays that have entered the light guide plate 2 from 4, 4b and continuously or discontinuously emit the directivity and the energy of the same light amount at any position. Also,
You may control the space | interval which the continuous optical element 20 'shown in FIG. 10 thru | or 12 adjoins according to the target brightness balance etc. FIG.

Further, as shown in FIG. 15, the first light deflection element 30 is provided on the back surface portion 9 of the light guide plate 2 continuously or continuously between the rows of the optical elements 20 rather than the optical elements 20. The first light deflection element 30 having a fine concave shape may be provided.

The first light deflection element 30 has a height of 1 μm to
It is formed finer than the optical element 20 in a range of 4 μm and a maximum width of 4 μm to 16 μm. Therefore, the first
The amount of light rays deflected by the light deflection element 30 is extremely smaller than the amount of light rays totally reflected by the optical element 20. This allows
Since it does not disturb the emission angle of the entire light beam emitted from the entire light guide plate 2 but only a part of it, it does not cause a decrease in the luminance from any viewing angle, and does not cause an unpleasant look. .

For example, a light ray L from the incident portion 7 of the light guide plate 2
0 is the refraction angle α = ± 42.38 ° in the case of acrylic resin
The light ray LL that has entered the light guide plate 2 within the range of, reaches the optical element 20, reaches the optical element 20, and is totally reflected by the inclined surface of the optical element 20 advances in the surface portion 8 direction.

The light rays LL totally reflected by the inclined surfaces of these optical elements 20 travel in the same direction uniformly by a plurality of rows of regular or continuous optical elements 20, and are emitted from the surface portion 8. The emitted light beam LL0 is also uniformly emitted in the same direction. This causes the generation of a visible spectrum due to the dispersion of light on the exit surface like a rainbow.

However, according to the structure of the light guide plate 2 of this example,
A part of the light ray L0 directed toward the back surface portion 9 has a diameter of 4 μm.
First light deflection element 3 having an arc shape in the range of about 16 μm
Reaches 0.

The first light deflection element 30 is the optical element 20.
Is very small compared to
The inclined surface of the first light deflection element 30 with respect to 0 is the optical element 2
A ray that is totally reflected at an angle different from the angle (total angle of reflection is smaller than that of the optical element 20) of the optical element 20 because the angle is different from that of the inclined surface of 0 (the angle between the inclined surface and the back surface portion 9 is large). L3 travels in the direction of the surface portion 8 and emits an outgoing light ray L30 from the surface portion 8 at an outgoing angle different from the outgoing light ray LL0 from the optical element 20.

Therefore, the emitted light beam L30 emitted from the surface portion 8 by the first light deflection element 30 is generated by a large number of emitted light rays LL0 in the same direction and having the same brightness appearing on the surface portion 8 by the optical element 20. The regularity of the visible spectrum is disturbed and the visible spectrum is made inconspicuous.

However, in reality, the visible spectrum does not disappear, and when viewed from the exit surface side (outside the surface portion), the first spectrum is obtained.
Of the light beam L30 emitted by the light deflection element 30 of
When viewed from L0, the continuity of the visible spectrum is lost due to the presence of diffused light), and the visible spectrum cannot be recognized.

Further, although not shown, the first light deflection element 3
Since the angle of the inclined surface of 0 is different from that of the inclined surface of the optical element 20, even light rays having different incident angles reach the same position as the totally reflected light ray from the optical element 20 at the position of the surface portion 8. Since the incident angle between the optical element 20 and the first light deflecting element 30 in 3 is different, the emitted light LL0 is disturbed due to the different outgoing angles, thereby disturbing the regularity of the visible spectrum and making the visible spectrum inconspicuous. To do.

Further, the first light deflector 30 does not only undergo total reflection, but also the light rays that have been refracted and transmitted through the first light deflector 30 and emitted from the back surface portion 9 are re-incident and travel in different directions to be visible. It disturbs the regularity of the spectrum and obscures the visible spectrum.

Further, as shown in FIG. 16, the optical element 2
When 0 is concave, the light ray L0 inside the light guide plate 2 is totally reflected once on the mirror surface of the light guide plate 2, and then the reflected light is reflected by the optical element 20.
16 (a), a visible spectrum (rainbow) appears in the air layer when the light is emitted to the concave air layer of FIG. 16 (a), and this visible spectrum is shown in FIG. 16 (b).
When the light enters the light guide plate 2 again at the concave arc bottom surface (upper part) as shown in FIG. 2, it is refracted and spreads further to the surface portion 8 direction of the light guide plate 2, and as light rising upward from the surface portion 8. Emits the visible spectrum (rainbow).

However, according to the configuration of this example, as shown in FIG. 17, the first light deflector 30 is provided in the vicinity of the optical element 20, so that the light ray L30 inside the light guide plate 2 is transmitted. Is once totally reflected by the mirror surface of the first mirror, and the reflected light is totally reflected by the inclined surface of the first light deflection element 30. Then, the totally reflected light ray L31 is totally reflected again on the critical surface of the optical element 20, and the totally reflected light ray L32 proceeds toward the surface portion 8 of the light guide plate 2 and remains as white light without being dispersed into the surface portion. It is emitted as light rising from 8.

Since the first light deflection element 30 is provided near the optical element 20, the light ray L3 in the light guide plate 2
0 is once totally reflected by the mirror surface of the light guide plate 2, and the reflected light is totally reflected by the inclined surface of the first light deflection element 30. As a result, the totally reflected light ray L31 ′ is blocked from traveling toward the optical element 20, travels in the direction of the surface portion 8 of the light guide plate 2, and is emitted as light rising upward from the surface portion 8 as white light without being dispersed. Emit.

As described above, when the optical element 20 has a concave shape or the like, and the portion where the light guide plate 2 and the concave optical element 20 are connected has two mirror surfaces such as a prism shape, the light guide plate 2 is formed.
The light ray from the inside is totally reflected once on the mirror surface of the light guide plate 2. Then, when the totally reflected light is emitted to the concave air layer of the optical element 20, a visible spectrum (rainbow) appears in the air layer due to Newton prism spectroscopy. However, according to the configuration of this example, the light totally reflected by the mirror surface of the light guide plate 2 is totally reflected by the first light deflection element 30 and is prevented from proceeding to the optical element 20. Occurrence can be prevented.

Further, when the visible spectrum (rainbow) as described in FIG. 16 is generated, the visible spectrum (rainbow) is refracted at the concave portion, spreads further, and advances toward the surface portion 8 of the light guide plate 2, and then from the surface portion 8 to the visible spectrum (rainbow). Stands up. However, as described with reference to FIG. 15, the regularity of the visible spectrum is disturbed by the light totally reflected from the first light deflection element 30, so that the visible spectrum can be made inconspicuous.

In addition to the above, a part of the light ray L0 is totally reflected by the back surface portion 9, and the totally reflected light reaches the front surface portion 8 and is totally reflected again to reach the optical element 20 and the like. Since this light ray is a repetition of total reflection, the incident angle to the optical element 20 is equivalent to the light ray L0, and the light ray reaching the optical element 20 or the first light deflecting element 30 obtains the action and effect described above. .

Further, although not shown, the incident portion 7 of the light guide plate 2
The light rays entering the light guide plate 2 from the end portions 7'of the front surface portion 8 and the rear surface portion 9 connected to the surface portion 8 and the rear surface portion 9 are repeatedly totally reflected and reach the emission surface by interference, and the brightness is different. Light is periodically generated like a striped pattern.

The directivity and brightness of the light source 3 together with the optical element 20 may cause the emitted light to be bright and dark by direct light from the optical element 20 and may cause a stripe pattern of bright and dark light.

However, according to the configuration of this example, the regularity of the bright and dark light generated on the emission surface is disturbed by the emission light beam L30 emitted to the front surface portion 8 and the back surface portion 9 by the first light deflection element 30. It is possible to prevent the generation of bright and dark stripes.

Although the first light deflection element 30 here has been described as having an arcuate concave shape with a diameter in the range of 4 μm to 16 μm, it has a conical shape and a maximum width in the range of 1 μm to 4 μm. May have a polygonal pyramid shape in the range of 4 μm to 16 μm.
Even in this case, as described above, if the light beam that is refracted or totally reflected is emitted to the place where the totally reflected light beam from the optical element 20 exists, the same action and effect can be obtained.

Further, the first light deflection element 30 has a higher brightness visible spectrum (rainbow) when the light source 3 has a strong luminance or the light source 3 having a strong directivity is closer to the incident portion 7 of the surface portion 8. ) Occurs and becomes more noticeable. For this reason, the first light deflector 30 is provided more as it is closer to the incident portion 7 of the back surface portion 9. Thereby, the generation of the visible spectrum (rainbow) can be further disturbed to make the visible spectrum (rainbow) inconspicuous.

Further, the first light deflection element 30 is the light source 3
Are randomly provided on the back surface portion 9 depending on the brightness of the light guide plate 2, the size of the light guide plate 2, and the like. This can disturb the generation of the visible spectrum (rainbow) from the entire light guide plate 2 and make the visible spectrum (rainbow) inconspicuous.

As described above, the first light deflection element 30 is visible by the optical element 20 itself (due to the regular existence of the optical element 20 etc.) in accordance with the conditions and specifications of the light source 3 and the light guide plate 2 and the purpose of use. It is also possible to prevent the generation of a spectrum (rainbow) and the stripe pattern of light and dark light due to the light and darkness of light having regularity due to the incident portion 7.

The description here is given for the first light deflection element 3.
0 and the optical element 20 are provided on the back surface portion 9 of the light guide plate 2, but the first light deflecting element 30 may be provided on the front surface portion 8, and these functions and effects are also provided on the back surface portion 9. Since it is similar to the case, the description of providing the light deflection element 30 on the surface portion 8 is omitted because it is redundant.

Although the shape of the first light deflection element 30 is described here as a fine concave shape, the action and effect are the same even if the shape is a fine convex shape. The description of the light deflection element 30 will be omitted because it is redundant.

Further, it is also possible to provide the first light deflection element 30 and the optical element 20 on the front surface portion 8 so that the emitted light is emitted from the direction of the rear surface portion 9 and used as a front light or the like.

Further, although not shown in the drawing, the light guide plate 2 is provided with a convex shape so that the light guide plate 2 and the diffusion sheet or the like provided near the front surface portion 8 or the rear surface portion 9 or the reflector 15 or the reflection case below the rear surface portion 9 are in contact with each other. This can be prevented by the first light deflection element 30, and the effect of the diffusion sheet or the like can be brought out. In addition, the convex first light deflection element 30 keeps an air layer between the light guide plate 2 and the reflector 15 or the reflection gate, and allows the surface of the reflector 15 or the reflection case to directly pass through the (white) light guide plate 2. You can make it invisible.

Further, the light guide plate 2 is, as shown in FIG.
In particular, a light ray incident into the light guide plate 2 from the end portion 7 ′ of the front surface portion 8 and the rear surface portion 9 connected to the incident portion 7 of the light guide plate 2 is located on the incident portion 7 and on the opposite side of the incident portion 7. Between the front surface portion 8 and the rear surface portion 9, the total reflection is repeated to generate bright and dark light having different brightness due to interference. Then, as shown in FIG. 19, when a bright and dark light beam reaches the optical element 20 provided on the back surface portion 9, a part of the light emitted from the front surface portion 8 is deflected by the optical element 20 and is slightly refracted. By providing the second light deflection element 40, the striped pattern of light and dark light composed of regular light and dark light is made inconspicuous.

The second light deflection element 40 has a diameter of 5 μm
The arc shape is in the range of 100 μm and the height is 1/20 to the diameter.
It is formed in a gentle arc shape with few protrusions in the range of 1/80 and a large radius of curvature. For this reason, the light beam totally reflected by the optical element 20 does not extremely change the emission angle even if it is refracted when entering the second optical deflecting element 40 and exiting, and the light guide plate 2 is partially refracted slightly. Therefore, it does not cause a decrease in brightness from an arbitrary viewing angle, and does not result in an unpleasant glimpse.

For example, a light ray L from the incident portion 7 of the light guide plate 2
0 is the refraction angle α = ± 42.38 ° in the case of acrylic resin
18 enters the light guide plate 2, and as shown in FIG.
In particular, a light ray incident into the light guide plate 2 from the end portion 7 ′ of the front surface portion 8 and the rear surface portion 9 connected to the incident portion 7 of the light guide plate 2 is located on the incident portion 7 and on the opposite side of the incident portion 7. Between the front surface 8 and the back surface 9 and the incident portion 7 and the reflection end surface portion 10, the total reflection is repeated to generate bright and dark light having different brightness due to interference. Then, as shown in FIG.
A light ray with light and darkness, which is directed from the incident portion 7 directly toward the back surface portion 9 or a light ray L0 which is repeatedly totally reflected in the light guide plate 2, reaches the optical element 20 and reaches the inclined surface of the optical element 20. As a light ray LL totally reflected by, the light travels toward the surface portion 8.

Then, the light ray itself that uniformly travels in the same direction by the optical element 20 includes brightness brightness and darkness, and the outgoing light ray LL0 emitted from the surface portion 8 also uniformly exits in the same direction, and the bright and dark light is emitted at the exit surface. The occurrence of bright and dark light striped patterns appears.

In addition, due to the directivity and the brightness of the light source 3 and the light source 4 together with the optical element 20, the emitted light may be bright and dark due to direct light from the optical element 20, and a stripe pattern of bright and dark light may be generated.

However, according to the configuration of this example, the optical element 2
A light ray LL that is totally reflected by an inclined surface of 0 and travels toward the surface portion 8
The light beam LL4 which is a part of the light beam reaches the second light deflection element 40 and has a gentle arc shape when emitted from the second light deflection element 40 (the normal line of the second light deflection element 40 and the light guide plate). A slight refraction is caused due to a small difference from the normal line of the surface portion 8 of 2. As a result, from the surface portion 8 to the optical element 20.
The outgoing light ray L40 is emitted at an outgoing angle slightly different from the outgoing light ray LL0. In addition, in FIG.
The locus of the outgoing light beam when there is no light deflection element 40
It is represented by L0 '.

As described above, the second light deflecting element 40 emits the outgoing light ray L40 to the surface portion 8 at an outgoing angle slightly different from the outgoing light ray LL0 from the optical element 20, so that regular bright and dark light is emitted. It is possible to prevent the occurrence of a striped pattern of bright and dark light having a periodicity that is disturbed by the outgoing light ray L40.

The first light deflection element 30 has been described, but
The light rays LL totally reflected by the inclined surfaces of these optical elements 20 are
Multiple rows of regular or continuous optical elements with regularity 2
The emitted light beam LL0 emitted from the surface portion 8 also uniformly emits in the same direction by 0, and a visible spectrum (rainbow) is generated on the emission surface by the light splitting like a rainbow.

However, according to the configuration of this example, the outgoing light beam L40 emitted from the second light deflecting element 40 has the same degree of brightness that appears on the surface portion 8 of the optical element 20, and travels in the same direction. The regularity of the visible spectrum (rainbow) generated by a large number of outgoing rays LL0 is disturbed to make the visible spectrum (rainbow) inconspicuous.

However, in reality, the visible spectrum (rainbow) does not disappear, but when viewed from the exit surface side (outside the surface portion), the outgoing light ray L40 (the outgoing light ray L0 is diffused when viewed from the second light deflection element 40). The presence of light loses the continuity of the visible spectrum and makes it impossible to recognize the visible spectrum (rainbow).

In addition to the above, although not shown, of the light rays refracted and incident on the light guide plate 2, a part of the light rays and the light rays L0 which directly go to the front surface portion 8 and directly enter the second light deflecting element 40 are included in the back surface portion 9. Also, the light rays that are totally reflected at and directly reach the second light deflecting element 40 toward the surface portion 8 also obtain the action and effect described above.

Further, the second light deflection element 40 is composed of the light source 3
The light sources 4 are randomly provided on the surface portion 8 depending on the brightness of the light source 4, the size of the light guide plate 2, and the like. As a result, the generation of the visible spectrum (rainbow) from the entire light guide plate 2 is disturbed by the outgoing light ray L40 to make the visible spectrum (rainbow) inconspicuous, and the rule of the striped pattern of bright and dark light generated from the entire light guide plate 2 is generated. The property can be disturbed by the outgoing light ray L40 to make the striped pattern inconspicuous.

The second light deflection element 40 has a higher brightness visible as the light source 3 or the light source 4 has a strong luminance or the light source 4 having a strong directivity is closer to the incident portion 7 of the surface portion 8. A spectrum (rainbow) is generated and becomes more noticeable. Therefore, the closer to the incident portion 7 of the surface portion 8, the second light deflecting element 4
Try to set many 0s. Thereby, the generation of the visible spectrum (rainbow) can be further disturbed to make the visible spectrum (rainbow) inconspicuous.

Further, the second light deflection element 40 is composed of the light source 3
Since the intensity of the totally reflected light from the optical element 20 is stronger as the incident portion 7 is closer to the light source 4 and the light source 4, the incident portion 7 of the surface portion 8 is closer to the incident portion 7 when the contrast of the emitted light appearing on the emission surface is more noticeable. The closer to, the brighter and darker the light will be, making it more noticeable. For this reason, the second light deflection element 40 is provided more as it is closer to the incident portion 7 of the surface portion 8. As a result, the generation of bright and dark light can be further disturbed and the bright and dark light can be made inconspicuous.

As described above, the second light deflection element 40 is formed by the optical element 20 itself (regular existence of the optical element 20 etc.) in accordance with the conditions and specifications of the light source 3, the light source 4 and the light guide plate 2 and the purpose of use. It is possible to prevent the generation of visible spectrum (rainbow) and the generation of bright and dark light.

Incidentally, the explanation here is based on the second light deflection element 4
0 and the optical element 20 are provided on the front surface portion 8 of the light guide plate 2, but the second light deflecting element 40 may be provided on the rear surface portion 9, and these actions and effects are also provided on the front surface portion 8. Since it is similar to the case, the second light deflection element 40 is provided on the back surface portion 9.
The description with is omitted because it is redundant.

Further, here, the shape of the second light deflecting element 40 is described as a convex shape, but since the action and effect are the same even if it is a concave shape, the description of the second light deflecting element 40 having a concave shape will be made. Omit it because it overlaps.

It is also possible to provide the second light deflection element 40 on the back surface portion 9 and the optical element 20 on the front surface portion 8 so that the emitted light is emitted from the direction of the back surface portion 9 and used as a front light or the like. .

As described above, the light from the light source 3 or the light source 4 is continuously or continuously provided at the position corresponding to the luminance distribution or the light energy distribution of the light source 3 or the light source 4 on the front surface 8 or the back surface 9 of the light guide plate 2. The optical element 20 having an inclined surface corresponding to the bundle is applied to the density distribution that functionally increases in proportion to the distance from the light source 3 or the light source 4 so that the brightness and energy from the light source 3 or the light source 4 are always equal. By the inclined surface of the optical element 20 which is continuous or continuously equivalent, total reflection, refraction and the like can be performed to emit continuous or continuous equivalent brightness and energy to the emission surface side.

Furthermore, the density distribution of the optical element 20 is functionally increased in proportion to the distance from the light source 3 or the light source 4 as the brightness or energy from the light source 3 or the light source 4 is attenuated. The product of the amount of light emitted and its solid angle can be made equal at any position of.

Further, a desired luminance distribution of the light guide plate 2 can be expressed by obtaining a lower light energy at a place where the optical element 20 is missing than at a place where the optical element 20 exists.

Furthermore, the concave or convex first light deflection element 30 finer than the optical element 20 is provided between the continuous optical element 20 and the continuous row of the optical elements 20. To As a result, a plurality of rows of continuous optical elements 2 are provided.
The output brightness is reduced with respect to the generation of a visible spectrum due to the spectrum of the light that appears on the exit surface due to the diffraction grating-like element by the zero or continuous optical element 20, the Newton prism spectroscopic element, or the white light source 4 having particularly strong directivity. It can be prevented without causing it. Moreover, due to the directivity and the brightness of the light source 3 and the light source 4, the direct light from the optical element 20 causes the brightness of the emitted light and the generation of a striped pattern due to the light and dark light due to the repeated total reflection on the front surface portion 8 and the rear surface portion 9. In contrast, the emission brightness can be prevented without lowering.

Further, the light rays that have entered the light guide plate 2 from the ends of the front surface portion 8 and the rear surface portion 9 connected to the incident portion 7 of the light guide plate 2 are repeatedly totally reflected by the front surface portion 8 and the rear surface portion 9 and interfere with each other. The second light deflection element 40 for minutely refracting a part of the periodic light / dark light rays having different brightnesses that reach the emission surface by the
Should be provided. As a result, it is possible to prevent the occurrence of periodic bright and dark striped patterns due to light and dark of light without lowering the emission brightness. Moreover, the optical element 20 slightly refracts a part of the visible light spectrum generated by a large number of outgoing light rays having the same brightness and traveling in the same direction on the exit surface, and the continuity of the outgoing light is disturbed. Can be prevented without lowering the emission brightness.

Further, as shown in FIG. 21, by the second light deflecting element 40 provided on the front surface 8 of the light guide plate 2 and the convex first light deflecting element 30 provided on the back surface 9, the front surface portion is formed. 8
It is possible to prevent the light guide plate 2 from being in close contact with the diffusion sheet 16 provided in the vicinity of or the reflector 15 or the reflection case provided in the vicinity of the back surface portion 9. Moreover, since the air layer is present between the diffusion sheet 16 and the light guide plate 2 due to the convex first light deflection element 30, the light emitted from the light guide plate 2 does not directly proceed into the diffusion sheet 16. The output angle can be further changed once by the refractive index of the light guide plate 2 to bring out the effect of the diffusion sheet 16.

If there is no air layer between the diffusion sheet 16 and the reflector 15, the surfaces of the diffusion sheet 16 and the reflector 15 (for example, as if the diffusion sheet 16 and the reflector 15 were integrated with the light guide plate 2 were formed). , White) It is directly visible through the light guide plate 2 (for example, the typeface on the paper placed under the flat glass is directly observed). However, according to the configuration of this example, the diffusion sheet 16 and the reflector are provided by providing the second light deflecting element 40 on the front surface portion 8 of the light guide plate 2 and the convex first light deflecting element 30 on the rear surface portion 9. An air layer can be secured between 15 and the light guide plate 2. Thereby, it is possible to prevent the surfaces of the diffusion sheet 16 and the reflector 15 from being directly seen through the light guide plate 2.

The light source 3 is in the form of a line such as a CCFL (cold shadow tube). Direct light is incident on the light guide plate 2 through the incident portion 7 of the light guide plate 2, and other light is reflected by the reflector 14 while being reflected by the reflector 14. Three
And enters the light guide plate 2 through the space between the reflector 14 and the reflector 14.

The light source may be a linear CCFL, or a semiconductor light emitting element or an array of semiconductor light emitting elements arranged as shown in FIGS. 4 to 9.

For example, the light source 4 shown in FIG. 4 and FIG. 5 is a semiconductor light emitting element, and is composed of an LED, a laser, etc., and is formed by using a monochromatic light or a white or fluorescent material of RGB (red, green, blue) or a fluorescent material. The thing converted into white light by converting is also used.

In addition, at the corner 6 where the two side surface portions 11 of the light guide plate 2 intersect, or when a plurality of incident parts 5 are provided, a light source 4 of a different emission color is used for each incident part from the entire light guide plate 2. White light may be emitted.

Further, as the light source 4b shown in FIG. 6, it is possible to use a semiconductor light emitting element which is arranged at equal intervals or arranged in such a manner that both end portions are densely arranged and which is integrated with resin or the like.

The reflector 14 is made of a white insulating material or a sheet or metal having a metal such as aluminum vapor-deposited thereon, and surrounds the incident portion 7 of the light guide plate 2, the light source 3, the light source 4 and the light source 4b. The light from the light source 3, the light source 4, and the light source 4b is reflected, and the reflected light is incident on the incident portion 7 of the light guide plate 2.
Incident again on.

Although not shown, the light-incident portion 7 of the light guide plate 2 is made of the same material for the light source 3, the light source 4, and the light source 4b.
The light source 3, the light source 4, and the light source 4b are surrounded, the light from the light source 3, the light source 4, and the light source 4b is reflected, and the reflected light is made incident on the incident portion 7 of the light guide plate 2 again.

The reflector 15 is made of a sheet in which a white material such as titanium oxide is mixed with a thermoplastic resin, a sheet of a thermoplastic resin, or a metal vapor deposition of aluminum or the like, a laminated metal foil or a sheet metal. Consists of. The reflector 15 covers the incident portion 7 and portions other than the incident portion 7 and the surface portion 8 and reflects the light from the light source 3, the light source 4 and the light source 4 b other than the light emitted to the surface portion 8 by the light guide plate 2. The light is diffusely reflected and is incident on the light guide plate 2 again so that all the light from the light source 3, the light source 4, and the light source 4b is emitted from the surface portion 8.

Although the correction sheet for finally controlling the distribution of light rays and the like is not provided above the light guide plate 2 in the flat illumination device, a correction sheet may be used if necessary. The correction sheet is made of a transparent resin or the like, and has unevenness for deflecting light on the surface. Since this correction sheet corrects the light emitted from the light guide plate 2, the light emitted from the light guide plate 2 is diffused, the light emitted from the light guide plate 2 is condensed, the light emitted from the light guide plate 2 is condensed, or the whole light is scattered or partially diffused. It also collects light. Therefore, select a diffusion sheet, condensing sheet, scattering sheet, diffusion condensing sheet, etc. that should be corrected according to the purpose, and use it with the processed surface facing forward or in the forward direction or in the reverse direction. To do.

[0163]

As described above, in the light guide plate according to the first aspect, the light from the light source has continuity in the front surface portion and / or the back surface portion at the position corresponding to the luminance distribution or the light energy distribution of the light source. An optical element having an inclined surface corresponding to the bundle is applied to a density distribution that increases functionally in proportion to the distance from the light source, and a concave shape finer than the optical element between the rows of continuous optical elements is provided. Since or / and the convex first light deflection element is provided, total reflection and refraction are always performed by the inclined surface of the optical element having the same continuity at a position where the luminance and energy from the light source are equal, and the light is emitted to the exit surface side. It is possible to emit brightness and energy equivalent to continuity. Moreover, the product of the amount of light emitted and the solid angle thereof is equal at any position of the light guide plate by increasing the density distribution of the optical element in proportion to the distance from the light source as the brightness and energy from the light source are attenuated. Can be emitted. In addition, the first light deflecting element causes the generation of the spectrum (rainbow) of light appearing on the emission surface by the first light deflecting element due to the white light source having a strong directivity or the like and the diffraction grating-like element by the plurality of rows of continuous optical elements. Since it is possible to diffuse a part of the light beam that goes to, the continuity of the visible spectrum (rainbow) is lost (disturbed), the recognition of the visible spectrum (rainbow) is disturbed, and the emission brightness of the emission surface is not reduced. Generation of the visible spectrum (rainbow) can be prevented.

Further, in the case of a concave optical element or the like, when the portion where the light guide plate and the concave optical element are connected has two mirror surfaces such as a prism shape, the visible spectrum (rainbow) that appears by Newton prism spectroscopy is It is possible to prevent the light ray traveling to the concave optical element from being totally reflected by the first light deflecting element in the near side to prevent the light ray from traveling to the optical element, thereby preventing generation of a visible spectrum (rainbow).

Further, by the convex first light deflecting element provided on the front surface or the back surface of the light guide plate, a diffusion sheet or the like provided near the front surface or the back surface or a reflector under the back surface or Since the case and the like and the light guide plate can be prevented from adhering to each other, the intended effect can be easily obtained without impairing the original functions of the diffusion sheet, the reflector, and the reflection case. Moreover, it is possible to obtain easily visible outgoing light without directly observing the diffusion sheet, the reflector, the reflective case, and the like.

Further, in the light guide plate according to the second aspect, the front surface portion and / or the rear surface portion has the inclined surface corresponding to the light flux from the light source continuously at the position corresponding to the luminance distribution or the light energy distribution of the light source. The optical element is provided with a density distribution that increases functionally in proportion to the distance from the light source, and between the rows of continuous optical elements, a concave shape finer than the optical element or /
Since the first light deflection element having a convex shape is provided, total reflection and refraction are always performed by the inclined surface of the same optical element continuously at the position where the brightness and energy from the light source are equal, and the continuity on the emission surface side is maintained. The same brightness and energy can be emitted. Moreover, the product of the amount of light emitted and the solid angle thereof is equal at any position of the light guide plate by increasing the density distribution of the optical element in proportion to the distance from the light source as the brightness and energy from the light source are attenuated. Can be emitted.
Moreover, although it is continuous, the product of the amount of light emitted from the optical element and its solid angle is equal by controlling the length of the optical element and the interval between adjacent optical elements,
Where the optical element is lost, lower light energy can be obtained than where the optical element is. In addition, the first light deflecting element shifts the generation of light spectrum (rainbow) appearing on the emission surface from the light source to the optical element by a diffraction grating-like element formed by a white light source having a strong directivity and a plurality of rows of continuous optical elements. Part of the rays of light that travel can be diffused so that the continuity of the visible spectrum (rainbow) is lost (disturbed).
It is possible to prevent the generation of a visible spectrum (rainbow) on the emission surface without disturbing the recognition of the emission and reducing the emission brightness.

Further, in the case of a concave optical element, etc., when the portion where the light guide plate and the concave optical element are connected has two mirror surfaces like a prism shape, the visible spectrum (rainbow) which appears by Newton prism spectroscopy is It is possible to prevent the light ray traveling to the concave optical element from being totally reflected by the first light deflecting element in the near side to prevent the light ray from traveling to the optical element, thereby preventing generation of a visible spectrum (rainbow).

Further, by the convex first light deflecting element provided on the front surface or the back surface of the light guide plate, a diffusion sheet provided near the front surface or the back surface or a reflector under the back surface or Since the case and the like and the light guide plate can be prevented from adhering to each other, the intended effect can be easily obtained without impairing the original functions of the diffusion sheet, the reflector, and the reflection case. Moreover, it is possible to obtain easily visible outgoing light without directly observing the diffusion sheet, the reflector, the reflective case, and the like.

Further, in the light guide plate according to the third aspect, the first light deflection element is provided on the front surface portion and / or the rear surface portion in a random manner or in a number closer to the incident portion and has a height of 1 μm.
Since it has a polygonal cone shape with a maximum width in the range of 4 μm to 16 μm or an arc shape or a cone shape with a diameter in the range of 4 μm to 16 μm in the range of 4 μm to 4 μm, it is finer than the optical element, and therefore the first The light emitted from the optical element can be controlled by the light beam deflected by the first light deflecting element without being greatly affected by the first light deflecting element. In addition, when a white light source has strong directivity or high brightness, a visible spectrum (rainbow) is generated on the exit surface in the vicinity of the incident part due to the light-splitting, due to the diffraction grating-like element with multiple rows of continuous optical elements. In the case of appearing, the first light deflection element is provided so as to be closer to the entrance portion of the front surface portion and / or the back surface portion so as to diffuse a part of the light ray traveling from the light source to the optical element or to emit a light ray having a different emission angle to the emission surface. Can be emitted. As a result, it is possible to prevent the generation of a visible spectrum (rainbow) on the emission surface without lowering the emission brightness, and it can be used regardless of the type of the light source or the shape of the light guide plate.

When the directivity of the white light source is weak, the light rays entering the light guide plate from the end portions of the front surface portion and the back surface portion connected to the incident portion of the light guide plate are totally reflected on the front surface portion and the back surface portion. By randomly providing a first light deflection element on the front surface portion and / or the back surface portion, a part of the light beam that goes to the optical element is traced. Can be diffused into. As a result, it is possible to prevent the occurrence of a periodic stripe pattern of bright and dark light on the emission surface without lowering the emission brightness.

Further, in the light guide plate according to the fourth aspect, the front surface portion and / or the back surface portion has a continuity at a position corresponding to the luminance distribution or the light energy distribution of the light source and has an inclination corresponding to the light flux from the light source. An optical element having a surface is applied to a density distribution that functionally increases in proportion to the distance from the light source, and a part of the light emitted by the optical element having continuity on the front surface or the back surface facing the optical element is Since the second light deflection element for making minute refraction is provided, total reflection or refraction is always performed by the inclined surface of the optical element having the same continuity at the position where the brightness and energy from the light source are the same, and the same brightness is obtained on the emission surface side. And energy can be emitted. Moreover, the product of the amount of light emitted and the solid angle thereof is equal at any position of the light guide plate by increasing the density distribution of the optical element in proportion to the distance from the light source as the brightness and energy from the light source are attenuated. Can be emitted. In addition, the light rays that have entered the light guide plate from the ends of the front surface portion and the back surface portion that are connected to the incident portion of the light guide plate undergo total reflection repeatedly on the front surface portion and the back surface portion, and the brightness reaches the emission surface due to interference A part of the light / dark light reaches the second light deflection element having a large diameter with respect to the height (a part of a so-called arc having a large radius of curvature) and is emitted from the second light deflection element to the outside. The light rays of time can be emitted at different emission angles that are smaller than those of the flat surface portion. Accordingly, it is possible to prevent the occurrence of a striped pattern of bright and dark light without slightly disturbing the periodic bright and dark light and lowering the emission brightness.

Further, a plurality of columns having regularity or a continuous optical element itself emits light uniformly in the same direction,
Even when a visible spectrum (rainbow) is generated on the exit surface due to the spectrum of light, a part of the light rays in the visible spectrum (rainbow) is slightly deflected to disturb the regularity of the visible spectrum and the visible spectrum (rainbow) is generated. To prevent the occurrence of visible spectrum (rainbow)
Can be made inconspicuous.

Furthermore, the second light deflecting element provided on the front surface or the back surface of the light guide plate can prevent the light guide plate from being in close contact with the diffusion sheet or the like provided near the front surface or the back surface.

Further, in the light guide plate according to the fifth aspect, the front surface portion and / or the back surface portion has the inclined surface corresponding to the light flux from the light source continuously at the position corresponding to the luminance distribution or the light energy distribution of the light source. The optical element is given a density distribution that increases functionally in proportion to the distance from the light source, and a part of the light emitted by the optical element continuously provided on the front surface or the back surface facing the optical element is slightly refracted. Since the second light deflection element is provided, total reflection or refraction is continuously performed by the inclined surface of the same optical element at a position where the brightness and energy from the light source are always the same, and the same brightness and energy are provided on the emission surface side. Can be emitted. Moreover, the product of the amount of light emitted and the solid angle thereof is equal at any position of the light guide plate by increasing the density distribution of the optical element in proportion to the distance from the light source as the brightness and energy from the light source are attenuated. Can be emitted. In addition, by controlling the lengths of the optical elements and the intervals between adjacent optical elements, which are continuous, the product of the amount of light emitted from the optical elements and the solid angle can be emitted equally. In addition, the light entering the light guide plate from the ends of the front surface and the back surface connected to the incident part of the light guide plate undergoes total reflection repeatedly on the front surface and the back surface, and reaches the emission surface by interference. A portion of the light / dark light beam having a certain property reaches a second light deflection element having a large diameter with respect to the height (a part of a so-called arc having a large radius of curvature), and is transmitted from the second light deflection element to the outside. When the light is emitted to the, the light is emitted at a different emission angle that is smaller than that of a flat surface portion, so that the light and dark light of the periodic light is slightly obstructed and the emission brightness is not reduced, so that a striped pattern of light and dark light is generated. Occurrence can be prevented.

Further, a plurality of columns having regularity or a continuous optical element itself emits light uniformly in the same direction,
Even when a visible spectrum (rainbow) is generated on the exit surface due to the spectrum of light, a part of the light rays in the visible spectrum (rainbow) is slightly deflected to disturb the regularity of the visible spectrum and the visible spectrum (rainbow) is generated. To prevent the occurrence of visible spectrum (rainbow)
Can be made inconspicuous.

Furthermore, the second light deflecting element provided on the front surface portion or the back surface portion of the light guide plate can prevent the diffusion sheet and the like provided near the front surface portion or the back surface portion from closely contacting with the light guide plate.

In the light guide plate according to the sixth aspect, since the diameter of the second light deflection element is an arc shape in the range of 5 μm to 100 μm, the height is in the range of 1/20 to 1/80 of the diameter.
Since the diameter is large with respect to the height (so-called a part of an arc having a large radius of curvature), the normal line of the second light deflecting element has only a slight difference from the normal line of the light guide plate. For this reason, since the difference in the emission angle is also small, it is possible to effectively act on the bright and dark light without affecting the luminance distribution of the emitted light.
The light deflection element itself is also inconspicuous.

Further, since the second light deflection elements are provided on the front surface portion or the rear surface portion in a random manner or closer to the incidence portion, the second light deflection element is provided inside the light guide plate from the end portions of the front surface portion and the back surface portion connected to the incidence portion of the light guide plate. The incident light ray is repeatedly totally reflected on the front surface and the back surface to generate bright and dark light with different brightness due to interference. In the vicinity of the incident portion of the light guide plate having particularly high luminance, the bright and dark fringe pattern is more noticeable than in other places, and thus the second light deflecting element is provided so as to be closer to the incident portion of the front surface portion or the back surface portion. As a result, it is possible to prevent the occurrence of distinct bright and dark stripes. As a result, it can be used regardless of the high-luminance light source or the position where the light source is provided.

Further, in the light guide plate according to the seventh aspect, since the optical element has a triangular, trapezoidal, or arcuate cross section and is continuous or discontinuous, the light guide plate enters the light guide plate from the incident portion. The triangular, trapezoidal and arcuate inclined surface of the light beam can exist at the position corresponding to the normal line of the light from the light source, and when these are continuous, the same brightness or energy is emitted at any position. Even if it is discontinuous, the same brightness and energy can be continuously emitted at any position.

In the light guide plate according to the eighth aspect, the height of the optical element is increased or / and the optical element is moved away from the light source.
Further, since the height is partially increased, even an optical element far from the light source can receive a light ray from the light source and can be totally reflected. As a result, even if the light source is far from the light source, a large amount of light can be emitted to obtain a uniform light emission brightness from the light guide plate regardless of the distance of the light source. It is possible to increase or decrease the amount of light emitted from the light guide plate and to change the angle of light output from any position of the light guide plate. Therefore, it is possible to control the brightness and the viewing angle at any desired position of the light guide plate.

Further, in the light guide plate according to the ninth aspect, since the angle formed by the inclined surface with the front surface portion and the back surface portion is in the range of π / 2−2 critical angle to the critical angle, the light beam guided into the light guide plate. By using the range from the maximum incident angle of to the minimum angle of breaking the critical angle, all the totally reflected light can break the critical angle. With this, a wide emission angle range from the emission surface of the light guide plate can be obtained, so that the required emission angle can be freely selected and can be adapted to the purpose.

In the light guide plate according to the tenth aspect, since the angle formed by the inclined surface with the front surface portion and the back surface portion approaches the critical angle in proportion to the distance from the light source, the brightness and energy from the light source are attenuated. However, the reflected light totally reflected in proportion to the distance from the light source is emitted at a small emission angle. For this reason, the product of the amount of light emitted and the solid angle thereof can be equally emitted at any position on the emission surface of the light guide plate. This makes it possible to obtain a uniform emission amount and a uniform viewing angle.

Furthermore, in the light guide plate according to the eleventh aspect, the inclined surface is formed by forming an arc inside or outside with respect to the center of the inclined surface, or by forming an arc partially inside and outside the inclined surface. Therefore, when the emission position in the light guide plate of the same size is an arc on the inside of the inclined surface, it can be brought closer to the light source side. When the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be condensed.

Further, the emission position in the light guide plate of the same size can be moved away from the light source side when the outside of the inclined surface is an arc. When the light source is near, the totally reflected light becomes parallel light, and when the light source is far, the totally reflected light can be diffused.

Further, since the inside and outside arcs are formed by one inclined surface and two different arcs are partially provided, the functions and effects such as condensing and diffusion can be obtained by one inclined surface. The amount of emitted light and the viewing angle can be freely controlled.

The flat illumination device according to claim 12 is:
The light source, the incident part for guiding the light from the light source, and the position having the continuity at the position corresponding to the brightness distribution or the light energy distribution of the light source and having the inclined surface corresponding to the light flux from the light source, the distance from the light source. An optical element provided with a density distribution that increases proportionally and functionally, and a concave shape and / or a convex shape finer than the optical element between the continuous optical element rows.
Light deflecting element or / and a light guide plate having a second light deflecting element for minutely refracting part of the light emitted by the optical element on the front surface or the back surface facing the optical element, and the incident portion of the light guide plate. And a reflector that covers the area other than the emission surface and reflects the leaked light from the light guide plate back into the light guide plate, so that the inclined surface of the optical element that is equivalent to the continuity at the position where the brightness and energy from the light source are always the same. Performs total reflection, refraction, etc.
Equal brightness and energy can be emitted to the emission surface side. In addition, the density distribution of the optical element increases functionally in proportion to the distance from the light source with the attenuation of the brightness and energy from the light source, and the amount of light emitted at any position of the light guide plate and its solid angle It is possible to control the output angle from the output surface by setting the angles of the inclined surfaces so that the output is the same.

Further, the first light deflecting element causes the generation of the spectrum (rainbow) of the light appearing on the emission surface by the white light source having a strong directivity and the diffraction grating-like element formed by the plurality of continuous optical elements from the light source. A part of the light beam that goes to the optical element can be diffused, and the light beam that has entered the light guide plate from the ends of the front surface and the back surface that connect to the incident part of the light guide plate repeats total reflection on the front surface and the back surface. The second light deflection having a large diameter (so-called a part of a circular arc having a large radius of curvature) with respect to the height of a part of the light / dark light rays having periodicity with different brightness, etc. Reach the element, this second
When the light is emitted from the optical deflector of (1) to the outside, it can be emitted at different emission angles which are smaller than those of the flat surface portion. With this, it is possible to prevent the occurrence of a stripe pattern of bright and dark light without slightly reducing the light and dark light of light having a periodicity and lowering the emission brightness.

Further, in the case of a concave optical element, etc., the visible spectrum (rainbow) which appears by Newton prism spectroscopy when the part where the light guide plate and the concave optical element are connected has two mirror surfaces like a prism shape, It is possible to prevent the light ray traveling to the concave optical element from being totally reflected by the first light deflecting element in the near side to prevent the light ray from traveling to the optical element, thereby preventing generation of a visible spectrum (rainbow).

Furthermore, even when a plurality of columns having regularity or a continuous optical element itself emits light uniformly in the same direction, and a visible spectrum (rainbow) is generated on the emission surface due to the spectrum of light, It is also possible to slightly deflect a part of the visible spectrum (rainbow) to disturb the regularity of the visible spectrum (rainbow), prevent the generation of the visible spectrum (rainbow), and make the visible spectrum (rainbow) inconspicuous. it can.

Further, the convex first light deflecting element and the second light deflecting element provided on the front surface and the back surface of the light guide plate allow the diffusion sheet and the back surface provided near the front surface and the back surface. It is possible to prevent contact between the light guide plate and a reflector or a reflection case under the light to be emitted. This makes it possible to easily obtain the desired effect without impairing the original functions of the diffusion sheet, the reflector, the reflection case, and the like, and to obtain the emitted light that is easy to see without directly observing the diffusion sheet, the reflector, the reflection case, or the like. be able to.

Further, in the flat illumination device according to the thirteenth aspect, the light source, the incident portion for guiding the light from the light source, and the light flux from the light source are continuously arranged at positions corresponding to the luminance distribution or the light energy distribution of the light source. An optical element having a corresponding inclined surface and having a density distribution that increases functionally in proportion to the distance from the light source, and a concave that is finer than the optical element between successive rows of optical elements. A first or second convex light-deflecting element or / and a second light-deflecting element for slightly refracting part of the light emitted by the optical element is provided on the front surface or the back surface facing the optical element. Since the light guide plate and the reflector that covers the light guide plate except for the incident part and the emission surface and reflects the leaked light from the light guide plate into the light guide plate again are provided, the light source and the light guide plate are continuously arranged at positions where the brightness and energy from the light source are equal. By the inclined surface of the optical element equivalent to Performs reflection or refraction, etc., can be emitted equivalent brightness and energy on the exit surface side. Moreover, the product of the amount of light emitted and the solid angle thereof is equal at any position of the light guide plate by increasing the density distribution of the optical element in proportion to the distance from the light source as the brightness and energy from the light source are attenuated. It is possible to continuously emit light or to change the emission angle from the emission surface and the optical element itself by setting the angle of the inclined surface.

Further, the generation of the spectrum of the light appearing on the emission surface by the first light deflecting element from the light source to the optical element by the white light source having a strong directivity or the like and the diffraction grating-like element by the continuous optical elements in a plurality of rows. It is possible to diffuse a part of the rays of light that are directed. As a result, the continuity of the visible spectrum (rainbow) is lost (disturbed), the recognition of the visible spectrum (rainbow) is disturbed, and the generation of the visible spectrum (rainbow) on the emission surface is prevented without lowering the emission brightness. it can.

Further, the generation of the spectrum of the light appearing on the emission surface by the white light source having a strong directivity and the diffraction grating-like element by the continuous optical elements in a plurality of rows is changed from the light source to the optical element by the first light deflection element. A part of the traveling light beam can be diffused, and the light beam that enters the light guide plate from the end of the front surface and the back surface that is connected to the incident part of the light guide plate repeats total reflection on the front surface and the back surface and interferes. A part of the light / dark light beam having periodicity with different brightness reaching the exit surface reaches the second light deflection element having a large diameter with respect to the height (a part of a so-called arc having a large radius of curvature). However, the light rays emitted from the second light deflection element to the outside can be emitted at different emission angles which are smaller than those of the flat surface portion. With this, it is possible to prevent the occurrence of a striped pattern of light and dark light without slightly disturbing the light and dark light having periodicity and lowering the emission brightness.

Further, in the case of a concave optical element, etc., when the portion where the light guide plate and the concave optical element are connected has two mirror surfaces such as a prism shape, the visible spectrum (rainbow) which appears by Newton prism spectroscopy is It is possible to prevent the light ray traveling to the concave optical element from being totally reflected by the first light deflecting element in the near side to prevent the light ray from traveling to the optical element, thereby preventing generation of a visible spectrum (rainbow).

[0195] Further, a plurality of columns having regularity or a continuous optical element itself emits light uniformly in the same direction,
Even when a visible spectrum (rainbow) is generated on the exit surface due to the spectrum of light, a portion of the visible spectrum (rainbow) is slightly deflected to disturb the regularity of the visible spectrum (rainbow) and It is also possible to prevent the occurrence of (rainbow) and make the visible spectrum (rainbow) inconspicuous.

Further, by the convex first and second light deflecting elements provided on the front surface and the back surface of the light guide plate, the diffusion sheet and the back surface provided near the front surface and the back surface are provided. It is possible to prevent close contact between the light guide plate and a reflector or a reflection case located underneath. This makes it possible to easily obtain the desired effect without impairing the original functions of the diffusion sheet, the reflector, the reflection case, and the like, and to obtain the emitted light that is easy to see without directly observing the diffusion sheet, the reflector, the reflection case, or the like. be able to.

Therefore, it is possible to prevent the generation of the visible spectrum (rainbow) due to the dispersion of the light appearing on the emission surface without lowering the emission brightness, and the directivity from the light source or the direct light from the optical element causes the emission light. It is possible to prevent the occurrence of light and dark stripes due to the bright and dark lights of the flat illumination device without lowering the output brightness. Depending on the necessary purpose of the flat lighting device, emphasis is placed on brightness, viewing angle, or uniformity. A wide design and a flat lighting device can be enabled.

Furthermore, in the flat illumination device according to the fourteenth aspect, since the light source is a white light source having a directivity or / and a directivity distribution, when the distance from the incident part of the light guide plate is not equal, It is possible to match the directivity in the distant direction. Thereby, the light from the light source can be efficiently used.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a flat lighting device according to the present invention.

FIG. 2 is a schematic view of a light guide plate according to the present invention.

FIG. 3 is a schematic view of a light guide plate according to the present invention.

FIG. 4 is a schematic view of a light guide plate according to the present invention.

FIG. 5 is a schematic view of a light guide plate according to the present invention.

FIG. 6 is a schematic view of a light guide plate according to the present invention.

FIG. 7 is a schematic view of a light guide plate according to the present invention.

FIG. 8 is a schematic view of a light guide plate according to the present invention.

FIG. 9 is a schematic view of a light guide plate according to the present invention.

FIG. 10 is a schematic view of a light guide plate according to the present invention.

FIG. 11 is a schematic view of a light guide plate according to the present invention.

FIG. 12 is a schematic view of a light guide plate according to the present invention.

FIG. 13 is a schematic view of a light guide plate according to the present invention.

14 is a partially enlarged view of the light guide plate of FIG.

FIG. 15 is a schematic trajectory diagram of light rays of a light guide plate according to the present invention.

16 (a) and 16 (b) are schematic trajectory diagrams of light rays of a light guide plate according to the present invention.

17 (a) and 17 (b) are schematic trajectory diagrams of light rays of the light guide plate according to the present invention.

FIG. 18 is a schematic trajectory diagram of light rays of a light guide plate according to the present invention.

FIG. 19 is a schematic trajectory diagram of light rays of a light guide plate according to the present invention.

FIG. 20 is a schematic trajectory diagram of light rays of a light guide plate according to the present invention.

FIG. 21 is a schematic view of a light guide plate according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Planar illumination device, 2 ... Light guide plate, 3, 4, 4b ... Light source,
5, 7 ... Incident part, 6, 6a, 6b ... End part, 8 ... Surface part,
9 ... Back surface part, 10 ... Reflection end surface part, 11 ... Side surface part, 14 ...
Reflector, 15 ... reflector, 16 ... terminal electrode, 20, 2
0 '... Optical element 21,22 ... Inclined surface, 21a, 21b
Interval, 30 ... Optical deflecting element, 40 ... Photorefractive element, β ... Incident angle, α ... Refractive angle, γ ... Critical angle, n ... Refractive index, θ ... Angle formed by front and back surfaces and inclined surface, L0, L1, L
11, L12, L2, L21, L22, L30, L4
0, LL, L3, LL4, LL0, LL0 '... Rays.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F21Y 103: 00 F21Y 103: 00 (72) Inventor Tatsuya Kato 6-22 Nagayama 6 Tama-shi, Tokyo 6 Japan La Inu Co., Ltd. (72) Inventor Karalu Karill 6-22-22 Nagayama, Tama City, Tokyo 6 F-Terms in Japan Light Co., Ltd. (reference) 2H038 AA55 BA06 2H091 FA14Z FA23X FA23Z FA31X FA31Z FA42X FA42Z FA45X FA45Z FB02 FB08 FC02 FD22 KA10 LA18 LA21

Claims (14)

[Claims] 1. A light guide plate having an incident portion for guiding light from a light source, a front surface portion for emitting the light, and a rear surface portion opposite to the front surface portion, wherein the front surface portion and / or the rear surface portion is provided. Is an optical element having a continuity at a position corresponding to the brightness distribution or the light energy distribution of the light source and having an inclined surface corresponding to the light flux from the light source, which is functionally increased in proportion to the distance from the light source. A light guide plate having a concave shape and / or a convex shape, which is finer than the optical elements, is provided between the rows of the continuous optical elements, which are provided in a continuous density distribution. . 2. A light guide plate having an incident portion for guiding light from a light source, a front surface portion for emitting the light, and a rear surface portion opposite to the front surface portion, wherein the front surface portion and / or the rear surface portion is provided. Is a density distribution in which an optical element having an inclined surface corresponding to a light flux from the light source continuously at a position corresponding to the luminance distribution or the light energy distribution of the light source is functionally increased in proportion to the distance from the light source. A light guide plate having a concave or / and convex shape that is finer than the optical elements and is provided between successive rows of the optical elements. 3. The first light deflection element is randomly provided on the front surface portion and / or the back surface portion or closer to the incident portion, and has a height in the range of 1 μm to 4 μm and a maximum width of 4 μm to. The light guide plate according to claim 1 or 2, wherein the light guide plate has a polygonal pyramid shape in the range of 16 µm or an arc shape or a conical shape in the diameter range of 4 µm to 16 µm. 4. A light guide plate having an incident portion for guiding light from a light source, a front surface portion for emitting the light, and a rear surface portion opposite to the front surface portion, wherein the front surface portion and / or the rear surface portion is provided. Is an optical element having a continuity at a position corresponding to the brightness distribution or the light energy distribution of the light source and having an inclined surface corresponding to the light flux from the light source, which is functionally increased in proportion to the distance from the light source. A second light deflecting element for subjecting the surface portion or the back surface portion facing the optical element to minute refraction of a part of the light emitted by the optical element having continuity. And a light guide plate. 5. A light guide plate having an entrance portion for guiding light from a light source, a front surface portion for emitting the light, and a back surface portion opposite to the front surface portion, wherein the front surface portion and / or the back surface portion is provided. Is a density distribution in which an optical element having an inclined surface corresponding to a light flux from the light source continuously at a position corresponding to the luminance distribution or the light energy distribution of the light source is functionally increased in proportion to the distance from the light source. And a second light deflecting element for slightly refracting part of the light emitted by the optical element continuously provided on the front surface portion or the back surface portion facing the optical element. Light board. 6. The second light deflection element has a diameter of 5 μm.
The arc shape is in the range of up to 100 μm and the height is
The light guide plate according to claim 4 or 5, wherein the light guide plate is provided in a range of 20 to 1/80 and is provided on the front surface portion or the back surface portion at random or closer to the incident portion. 7. The conductive element according to claim 1, wherein the optical element has a triangular shape, a trapezoidal shape, an arc shape in cross section, and is continuous or discontinuous. Light board. 8. The optical element according to claim 1, wherein a height of the optical element is increased and / or a height of the optical element is partially increased as the distance from the light source increases. The light guide plate described. 9. The inclined surface has an angle between the front surface portion and the back surface portion that is in the range of π / 2-2 critical angle to the critical angle. The light guide plate according to any one of 1. 10. The inclined surface has an angle formed with the front surface portion and the back surface portion that approaches a critical angle in proportion to a distance from the light source. The light guide plate of Crab. 11. The inclined surface forms an arc inside or outside with respect to the center of the inclined surface, or partially inside and outside the inclined surface. The light guide plate according to any one of claims 1, 2, 4, and 5. 12. A light source, an incident portion for guiding light from the light source, and an inclined surface having continuity at a position corresponding to a brightness distribution or a light energy distribution of the light source and corresponding to a light flux from the light source. An optical element having a density distribution that functionally increases in proportion to a distance from the light source, and a concave shape finer than the optical element between the continuous rows of the optical elements or And / or a convex first light deflection element and / or a second light deflection element for minutely refracting part of the light emitted by the optical element on the front surface or the back surface facing the optical element. A flat lighting device comprising: a light guide plate; and a reflector that covers a portion other than an incident portion and an emission surface of the light guide plate and reflects leak light from the light guide plate into the light guide plate again. 13. A light source, an incident portion for guiding light from the light source, and an inclined surface corresponding to a light flux from the light source continuously at a position corresponding to a luminance distribution or a light energy distribution of the light source. An optical element provided with a density distribution that increases functionally in proportion to the distance from the light source, and a concave shape finer than the optical element or / and between continuous rows of the optical elements. A light guide plate provided with a convex first light deflection element and / or a second light deflection element for slightly refracting part of light emitted by the optical element on a front surface portion or a back surface portion facing the optical element. And a reflector that covers a portion of the light guide plate other than the incident portion and the exit surface and that reflects the leaked light from the light guide plate back into the light guide plate. 14. The flat lighting device according to claim 12, wherein the light source is a white light source having a directivity or / and a directivity distribution.