JP2013080120A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, as a display device that is enabled to display two or more kinds of patterns such as characters and signs in different colors or differently timed on a single face of a light guide plate, a display device prevented from allowing streak-like non-uniformity to appear on the display face.SOLUTION: A display device is so configured that a plurality of display pattern parts each comprising a group of many dots are formed on a face of a light guide plate 1; light rays are brought to incidence in different directions from a plurality of light sources 12A and 12B on an end face side of the light guide plate; inner reflective faces, as reflective concaves 16A and 16B constituting the dots, are so configured as to constitute tapered faces of or close to the shape of part of a conical face, namely taper faces inclined in a direction orthogonal to the plate face and constituting tapered faces curved within a plane parallel to the plate face so that the convexly curved side of the tapered faces is directed toward the light sources and, moreover, other faces of the reflective concaves than the tapered faces do not substantially guide light rays from the light sources to the other plate face.

Description

  The present invention relates to a display device for displaying a two-dimensional pattern such as a picture, a character, a symbol, or a pattern as various display devices, and more particularly to two-dimensional information to be displayed on the surface of a light guide plate made of a transparent material. A large number of dots (small concave portions) are formed in a corresponding pattern, light is incident on the light guide plate from the end surface of the light guide plate, and the light is reflected by the reflection surface in the dot, thereby emitting the pattern. The present invention relates to a display device to be displayed.

  Recently, on the surface of the light guide plate made of a transparent material such as acrylic resin, polycarbonate resin, glass, etc., a number of dots consisting of minute recesses are formed according to a pattern such as a predetermined pattern, characters, symbols, patterns, In addition, a light source such as an LED is disposed on the end face of the light guide plate, and light incident on the light guide plate from the light source is reflected by the inner side surfaces of a large number of dots composed of minute recesses, whereby a predetermined pattern is obtained. A display device that emits light is displayed in practical use.

  As this type of display device, there is one in which two or more types of patterns such as patterns, characters, symbols, and patterns are displayed in different colors or at different timings on one plate surface on the same side of the light guide plate. It has been developed (for example, Patent Document 1 and Patent Document 2).

A typical example of the prior art is schematically shown in FIGS.
In FIG. 13, a first light source 12 </ b> A made of an LED or the like is disposed on one end face 2 side of the light guide plate 1 made of a transparent material having a rectangular shape as a whole so as to be in contact with or close to the end face 2. On the other end surface 3 side that is perpendicular to the end surface 2, a second light source 12 </ b> B made of LED or the like is disposed so as to be in contact with or close to the end surface 3. Here, the first light source 12A and the second light source 12B may emit light of the same color, but for the sake of clarity, the first light source 12A emits red light. The second light source emits blue light.

  On one plate surface 6 of the light guide plate 1, two display pattern portions 14A and 14B, that is, the first display pattern portion 14A and the second display pattern portion are formed by a large number of dots each formed of a minute reflecting recess. 14B is formed. Here, the first display pattern portion 14A is, for example, an alphabetic capital letter “A” pattern, and the second display pattern portion 14B is, for example, an alphabetic capital letter “B” pattern. As shown in FIGS. 14, 15, and 16, the dots constituting the display pattern portions 14 </ b> A and 14 </ b> B are each configured by a reflective recess 16 that is cut (depressed) from the plate surface 6 of the light guide plate 1. ing. Each of the reflecting recesses 16 is formed such that its vertical cross-sectional shape is a letter shape. More specifically, each reflecting recess 16 has a rectangular shape when viewed in plan from the plate surface 6 side, and one flat surface 16 </ b> A along the length direction of the rectangle is formed on the plate surface 6 of the light guide plate 1. The other plane 16B that faces the plane 16A and extends along the length direction of the rectangle is perpendicular to the plate surface 6 of the light guide plate 1. It is considered as a surface.

  Here, the dots belonging to the first display pattern 14 </ b> A and the dots belonging to the second display pattern 14 </ b> B are determined so that the directions of the reflection concave portions 16 are different. That is, the concave portions 16 for reflecting dots belonging to the first display pattern 14A have a length direction parallel to the one end face 2 of the light guide plate (that is, incidence of light from the first light source 12A). The reflecting surface 16A is formed to be inclined at a predetermined angle (for example, 45 degrees) with respect to the first light source 12A. On the other hand, the concave portions 16 for reflecting dots belonging to the second display pattern 14B have a length direction parallel to the other end surface 3 of the light guide plate (that is, with respect to the incident direction of light from the second light source 12B). And the reflecting surface 16A is inclined with respect to the second light source 12B at a predetermined angle (for example, 45 degrees). Therefore, in this case, the reflecting surface 16A of the reflecting recess 16 for dots belonging to the first display pattern 14A causes the light from the first light source 12A to face the plate surface 7 in a direction substantially perpendicular to the plate surface 6. The reflection surface 16B of the reflection concave portion 16 for the dots belonging to the second display pattern 14B reflects the light from the second light source 12B toward the plate surface 7 in a direction substantially perpendicular to the plate surface 6. I will let you. In addition, since surfaces other than the reflection surface 16 </ b> A in each reflection recess 16 are perpendicular to the plate surface 6 of the light guide plate 1, the light from each of the light sources 12 </ b> A and 12 </ b> B is directed toward the plate surface 7. Does not substantially reflect.

  Therefore, in such a display device, the red light incident on the light guide plate 1 from the first light source 12A is reflected on the plate surface by the reflection surface 16A of each dot (reflection recess 16) constituting the first display pattern 14A. The letter “A” of the first display pattern 14A, which is reflected toward the dot 7 and consists of an aggregate of these dots, is displayed with red light on the plate surface 7 side. Further, the red light from the first light source 12A is not reflected toward at least the plate surface 7 by each dot (reflection concave portion 16) constituting the second display pattern 14B. On the other hand, the blue light incident on the light guide plate 1 from the second light source 12B is reflected toward the plate surface 7 by the reflection surface 16A of each dot (reflection recess 16) constituting the second display pattern 14B. The letter “B” of the second display pattern 14B made up of an aggregate of these dots is displayed with blue light on the plate surface 7 side. Further, the red light from the second light source 12B is not reflected toward at least the plate surface 7 by each dot (reflection concave portion 16) constituting the second display pattern 14B. In this way, the letter “A” of the first display pattern 14A is displayed on the plate surface 7 of the light guide plate 1 with red light, and at the same time, the letter “B” of the second display pattern 14B is blue light. Is displayed.

  By the way, in the conventional display apparatus shown by FIGS. 13-16, when the display pattern was visually observed, there existed a problem that a stripe | line | muscle nonuniformity will be observed. This is because the reflecting surface of the reflecting recess that constitutes the dots of the display pattern is flat, and in this type of display device, the light that reaches the reflecting surface of the reflecting recess is in one direction facing the reflecting surface. Due to not only from.

That is, as a light source in a display device for displaying a pattern having a certain spread, it is rare to use a single point light source. In practice, a plurality of point light sources are arranged or a linear light source is used. Often used. For example, in the example of FIG. 13, a plurality of light emitting elements 12A ₁ , 12A ₂ , 12A ₃ such as LEDs are actually spaced apart in the length direction of the end face 2 as the first light source 12A on the end face 2 side. In general, the light sources 12B ₁ , 12B ₂ , and 12B ₃ such as LEDs are arranged in the length direction of the end face 3 as the second light source 12B on the end face 3 side. Generally, they are arranged side by side at intervals. Accordingly, the light reaching the reflecting surface of each reflecting recess is not only from one direction in the front, but also in various directions within the plane along the direction in which the light emitting elements are arranged (the length direction of the end face of the light guide plate). Usually it will come from. The same applies to the case where the linear light source is disposed on each of the end surface 2 and the end surface 3 along the length direction thereof.

  On the other hand, as schematically shown in FIG. 17, the reflecting surface 16A of the reflecting recess 16 is a plane having a certain length and a certain width. If light enters the plane from different directions, the reflected light is reflected. Will also be reflected in different directions. Therefore, an image (reflected image) obtained by viewing the light reflected by the reflecting surface 16A of each reflecting recess 16 from the plate surface 7 side appears as an image stretched parallel to the direction in which the light emitting elements are arranged. Further, it is considered that the stretched reflected images are continuously formed by the reflected light from the reflecting surfaces of the adjacent reflecting recesses, and a streak pattern (unevenness) appears.

  Such streak-like unevenness is a visual noise for patterns, characters, symbols, patterns, and the like that should be originally displayed. Therefore, the appearance of streaky unevenness is avoided in display devices that require beautiful and precise display. It is highly desired.

JP 2006-75362 A JP 2008-275921 A JP 2001-31233 A

  The present invention has been made in the background of the above circumstances, two or more patterns such as patterns, characters, symbols, patterns, etc., on different colors, on one plate surface (pattern display surface) on the same side of the light guide plate, Alternatively, as a display device that is displayed at different timings, a streak-like unevenness is prevented from appearing on the pattern display surface, thereby providing a display device that performs beautiful and precise display with less noise. It is an issue.

  As a technique for solving the above-described problems, particularly a technique for preventing the appearance of streak irregularities, the present inventors change the shape of the concave portion for reflection (inner surface shape), particularly the shape of the reflective surface. Thought. Then, attention is paid to the fact that the reflecting surface is a conical surface instead of a conventional general plane (inclined plane).

  Here, as the concave portion for reflection in the display device, a conical concave portion 16 as shown in FIG. 18 is formed and its side surface (conical surface) is used as the reflective surface 16A itself, for example, as shown in FIG. It has been conventionally known from a) and Patent Document 3. In such a conical recess 16 for reflection, the reflecting surface (conical surface) 16A is continuous over the entire circumference, so that the surface orthogonal to the cone axis O as shown in FIG. The light coming from various directions toward the axis O is all reflected in a direction parallel to the axis O by the reflecting surface 16A made of a conical surface. Therefore, even when a plurality of light emitting elements are arranged as described above, the reflected image viewed from the plate surface 7 side is not stretched in parallel with the direction in which the light emitting elements are arranged, and thus the above-described streak unevenness occurs. Hard to do. However, when the conical surface is the reflecting surface 16A, all the light coming from any direction in the plane orthogonal to the axis O is reflected toward one plate surface, so the display as shown in FIG. Even when applied to the apparatus, different patterns cannot be displayed in different colors. That is, when all of the reflective concave portions 16 constituting the dots of the display pattern portions 14A and 14B in the display device shown in FIG. 13 are replaced with conical concave portions, the red light and the second light source from the first light source 12A. All of the blue light from 12B is reflected toward the plate surface 7 by the reflecting surfaces (conical surfaces) of the reflecting concave portions 16 of the first and second display pattern portions 14A and 14B, and therefore the first and first display pattern portions 14A and 14B are reflected. The two display pattern portions 14A and 14B are all displayed with mixed color light of red light and blue light.

  Therefore, the fact that the reflecting surface of the reflecting concave portion is a conical surface as it is is a display device for displaying two or more types of patterns in different colors or at different timings, which is a basic premise of the present invention. Not applicable. Therefore, the present inventors, when using a part of the conical surface (tapered surface) as the reflecting surface of the reflecting recess, prevents the appearance of streak unevenness, and at least two types of patterns, The present inventors have found that they can be displayed in different colors or at different timings, and have made the present invention.

  Therefore, in the present invention, basically, it is assumed that light is incident in a different direction from a plurality of light sources into a light guide plate to display different patterns at different colors or at different timings. As the reflective concave portion constituting the dot, the inner reflective surface is inclined with respect to a part of the side surface of the conical surface or a tapered surface having a shape close thereto, that is, in a direction perpendicular to the plate surface, and parallel to the plate surface. The tapered surface is curved in the plane, and the convex curved side of the tapered surface is directed to the corresponding light source.

That is, the display device according to the basic aspect (first aspect) of the present invention is:
A light guide plate made of a transparent material and having a plurality of display pattern portions each formed of an aggregate of a large number of dots on one of the two plate surfaces;
A plurality of light sources for making light incident in different directions along the one plate surface of the light guide plate from the end surface side of the light guide plate into the light guide plate,
Each dot constituting the plurality of display pattern portions is constituted by a reflective concave portion that is recessed from the one plate surface of the light guide plate, respectively.
In addition, the reflection concave portion of each dot is formed by a tapered surface in which a part of the inner surface is inclined with respect to a direction orthogonal to the one plate surface and curved in a plane parallel to the one plate surface. The tapered surface is a reflecting surface that reflects light from any one of the plurality of light sources toward the other plate surface,
Furthermore, among the inner surfaces of the reflective recesses of each dot, the surface other than the tapered surface is configured not to substantially guide the light from each light source to the other plate surface,
The convex curved side of the tapered surface of the reflecting concave portion constituting the dot is directed toward a different light source for each display pattern portion to which the dot belongs, and reflects light from a different light source toward the other plate surface. It is comprised so that it may carry out.

In such a display device of the first aspect, a plurality of display pattern portions each composed of an aggregate of a large number of dots are formed on one plate surface (hereinafter referred to as “dot formation surface”) of the light guide plate. Yes. Each dot is constituted by a reflective recess that is recessed from the dot formation surface.
Further, the inner surface of the reflective recess has a tapered surface (reflective surface) that reflects light from one of the light sources toward the other plate surface of the light guide plate (hereinafter referred to as “pattern display surface”), and the other A surface (a surface that does not substantially guide light from each light source to the other plate surface).

And the taper surface of each reflective concave portion constituting the dot of a certain display pattern portion (hereinafter referred to as “first display pattern portion”) among the plurality of display pattern portions is a specific light source having a convex curved side ( The tapered surface of each of the reflecting concave portions that is directed to the “first light source” and forms dots of another display pattern portion (hereinafter referred to as “second display pattern portion”) has a convex curve. The side is directed to another light source (hereinafter referred to as “second light source”).
Therefore, the light from the first light source is reflected toward the pattern display surface by the tapered surface of the reflecting concave portion constituting the dots of the first display pattern portion, and the dots of the first display pattern portion. Emits light, and a pattern such as a predetermined pattern or character is displayed on the first pattern display unit by the set of the emitted dots. At this time, since the light from the second light source is not guided to the pattern display surface by the reflection concave portions constituting the dots of the first pattern display unit, the first pattern display unit The light is displayed only by the light from the light source.
On the other hand, the light from the second light source is reflected toward the pattern display surface by the tapered surface of the reflecting concave portions constituting the dots of the second display pattern portion, and the dots of the second display pattern portion , And a pattern such as a predetermined pattern or character is displayed in a light-emitting manner on the second pattern display section by the set of the emitted dots. At this time, since the light from the first light source is not guided to the pattern display surface by the reflection concave portions constituting the dots of the second pattern display unit, the second pattern display unit The light is displayed only by the light from the light source. Therefore, for example, if the emission colors are different between the first light source and the second light source, the respective patterns can be displayed in different colors in the respective pattern display units.

  Here, in the above description, the case where the first and second pattern display units, that is, the two pattern display units are provided and the two light sources are provided corresponding thereto is described. In the case of having a large number of pattern display portions and correspondingly three or more light sources, different pattern display portions can be caused to emit light by the light from each light source. Of course.

  Further, the reflecting surface of the reflecting recess that constitutes each dot is inclined with respect to a direction orthogonal to the dot forming surface and is formed by a tapered surface that is curved in a plane parallel to the dot forming surface, so that dot formation is performed. Light that reaches the tapered surface (convex curved surface) from each light source in a plane parallel to the surface is reflected in one direction along the direction orthogonal to the dot formation surface, or in a narrow angle range including that direction. Is done. Therefore, there is little possibility that the image of the reflected light from the reflecting surface of each dot will be stretched in a certain direction as in the case of the prior art in which the reflecting surface is a flat surface. Therefore, even if the interval between adjacent dots (recesses for reflection) is reduced, the reflection image of each adjacent dot is continuous, and there is little possibility that a streak pattern (streaks unevenness) will appear.

A display device according to a second aspect of the present invention is the display device according to the first aspect,
The surface other than the tapered surface is a surface perpendicular to the one plate surface.

  According to such a display device of the second aspect, light incident on each surface other than the tapered surface from each light source in a plane parallel to the dot formation surface from each light source is reflected in a direction parallel to the dot formation surface. Or refraction does not occur, so that it is effectively prevented from being guided to the pattern display surface.

A display device according to a third aspect of the present invention is the display device according to the first aspect,
The surface other than the tapered surface is a surface that is inclined with respect to the one plate surface, and the inclination direction is determined in a direction that does not reflect or refract light from each light source toward the other plate surface. It is characterized by that.

  According to such a display device of the third aspect, light incident from each light source to a surface other than the tapered surface within a plane parallel to the dot formation surface, particularly from the opposite side to the tapered surface. Thus, it is possible to reliably prevent the emitted light from being guided to the pattern display surface.

A display device according to a fourth aspect of the present invention is the display device according to the first aspect,
The tapered surface is a surface having a shape corresponding to a part of a side surface of a right cone having an axis perpendicular to the one plate surface.

  According to the display device of the fourth aspect as described above, all the light that has reached the tapered surface (convex curved surface) from each light source in a plane parallel to the dot forming surface is along the direction orthogonal to the dot forming surface. Reflected along one direction (one direction parallel to the axis of the original conical cone), so that the reflected light from the reflecting surface of each dot as in the prior art with the reflecting surface as a plane As a result, it is possible to reliably prevent the image from being stretched in a certain direction. As a result, even when the interval between the adjacent dots (reflection concave portions) is small, the images of the adjacent dots are continuously generated. It is possible to reliably prevent the appearance of a pattern (streaks unevenness).

A display device according to a fifth aspect of the present invention is the display device according to the fourth aspect,
The inner surface of the concave portion for reflection is formed in the shape of one divided cone when the right cone is divided by one or more planes including its rotation axis. is there.

  Such a display device of the fifth aspect has two or more display pattern portions and two or more light sources, and the two or more light sources are arranged on end surfaces on different sides of the light guide plate. That is, it is effective when the direction of incident light from each light source is different.

Furthermore, the display device according to the sixth aspect of the present invention is the display device according to the fourth aspect,
The reflective recess is formed in the shape of one divided truncated cone when the truncated cone is divided by one or more planes including the rotation axis.

  The display device of the sixth aspect also functions in the same manner as when the shape of the right cone is divided as the inner shape of each reflecting recess.

Furthermore, the display device according to the seventh aspect of the present invention is the display device according to any one of the first to sixth aspects,
At least one of the plurality of light sources is constituted by a plurality of light emitting elements arranged in a direction along an end surface of the light guide plate.

  As is apparent from the above description, streak unevenness uses a plurality of light emitting elements as a light source for emitting and displaying dots in one display pattern portion, and these light emitting elements are arranged along the end face of the light guide plate. This is likely to occur when they are arranged in one direction. However, if any one of the first to sixth aspects is assumed, even when a plurality of light emitting elements constituting the light source are arranged in one direction along the end surface of the light guide plate, the appearance of streak is surely suppressed. It can be done.

    According to the display device of the present invention, two or more types of patterns such as patterns, characters, symbols, and patterns are formed on one plate surface (pattern display surface) on the same side of the light guide plate, with different colors or at different timings. At the same time, it is possible to suppress the appearance of streaky irregularities on the pattern display surface, thereby making it possible to display a beautiful and precise pattern with less noise.

1 is a schematic plan view showing a first embodiment of a display device of the present invention. It is an expanded sectional view in the II line of FIG. It is an expanded sectional view in the II-II line of FIG. It is a figure which shows the recessed part for reflection which comprises the dot of each pattern display part in 1st Embodiment shown by FIG. 1, (A) is typical about the recessed part for reflection which comprises the dot of the 1st pattern display part. FIG. 5B is a schematic perspective view of the reflective concave portion constituting the dots of the second pattern display portion. It is a typical top view which shows 2nd Embodiment of the display apparatus of this invention. FIG. 6A is a perspective view and FIG. 5B is a plan view schematically showing a reflective concave portion that constitutes a dot of each pattern display portion in the second embodiment shown in FIG. 5. It is a typical top view which shows 3rd Embodiment of the display apparatus of this invention. It is a figure which shows another example of the recessed part for reflection in the display apparatus of this invention, (A) is a typical perspective view of the shape of the recessed part for reflection, (B) is a longitudinal cross-sectional view of the recessed part for reflection containing a light-guide plate. is there. It is a figure which shows another example of the recessed part for reflection in the display apparatus of this invention, (A) is a typical perspective view of the shape of the recessed part for reflection, (B) is a typical top view of the shape of the recessed part for reflection. It is. It is a figure which shows another example of the recessed part for reflection in the display apparatus of this invention, (A) is a typical perspective view of the shape of the recessed part for reflection, (B) is a typical top view of the shape of the recessed part for reflection. It is. It is a figure which shows another example of the recessed part for reflection in the display apparatus of this invention, and is a typical perspective view of the shape of the recessed part for reflection. It is a figure which shows another example of the recessed part for reflection in the display apparatus of this invention, and is a typical perspective view of the shape of the recessed part for reflection. It is a top view which shows typically an example of the conventional display apparatus. It is a typical top view which expands and shows the part of the arrow III of FIG. It is a figure which expands and shows the recessed part for reflection which comprises the dot of the 1st pattern display part in the conventional display apparatus shown by FIG. 13, (A) is a top view, (B) is VV of (A). (C) is sectional drawing in the VI-VI line of (A). It is a figure which expands and shows the recessed part for reflection which comprises the dot of the 2nd pattern display part in the conventional display apparatus shown by FIG. 13, (A) is a top view, (B) is VII-VII of (A). (C) is sectional drawing in the VIII-VIII line of (A). It is a typical perspective view which shows the effect | action of the reflective surface of the recessed part for reflection which comprises the dot of the pattern display part in the conventional display apparatus shown by FIG. It is a typical perspective view which shows the effect | action of the reflective surface of the recessed part for reflection which comprises the dot of the pattern display part in another conventional display apparatus.

Hereinafter, embodiments of the present invention will be described in detail.
1 to 4 show a first embodiment of a display device of the present invention.
In FIG. 1, a light guide plate 1 made of a transparent material such as acrylic resin, polycarbonate resin, or other glass is formed in a square plate shape having a certain thickness. Here, the transparent material includes not only a colorless and transparent material but also a colored and transparent material. In the present embodiment, the transparent material is made of a colorless and transparent material.
A plurality of (four in the illustrated example) light emitting elements 12A ₁ , 12A ₂ , 12A ₃ , 12A ₄ such as LEDs are disposed on one end face 5 of the light guide plate 1 along the length direction thereof. These 12A ₁ to 12A ₄ constitute a first light source 12A. In this embodiment, the light emitting elements 12A _{1 to} 12A ₄ of the _first light source 12A emit red light.
In addition, a plurality of (four in the illustrated example) light emitting elements 12B _{1 to} 12B ₄ such as LEDs are disposed along the length direction of the end surface 3 of the light guide plate 1 opposite to the end surface 5. These 12B ₁ to 12B ₄ constitute the second light source 12B. In the present embodiment, the light emitting elements 12B _{1 to} 12B ₄ of the second light source 12B each emit blue light.

Of the two plate surfaces 6 and 7 in the light guide plate 1, one plate surface 6 (the back side surface in FIG. 1; appearing in FIGS. 2 and 3) is a dot formation surface as described later, The other plate surface 7 is a pattern display surface that emits light in a desired pattern and displays the pattern.
The dot forming surface 6 emits red light from the first light source 12A to display a predetermined pattern on the pattern display surface 7 in red, and the second display pattern portion 14A. A second display pattern portion 14B for emitting blue light from the light source 12B to display a predetermined pattern on the pattern display surface 7 in blue is formed.
Each of the first and second display pattern portions 14A and 14B represents a pattern such as a picture, a character, a symbol, a pattern, or the like by a set of a large number of dots each composed of a minute reflecting recess as described later. It is. In the present embodiment, uppercase alphabetic character patterns “A”, “B”, and “C” are formed by dots in the first display pattern portion 14A, and the second display pattern portion 14B The upper case alphabetic character patterns “D”, “E”, and “F” are formed by dots.

  A large number of dots constituting the first and second display pattern portions 14A and 14B are each a vertical plane including a right cone and its axis O, as schematically shown in FIGS. It is comprised by the recessed part (reflective recessed part) 16 which makes the shape divided into 2 vertically, ie, the shape of a cone bisection. In addition, about the code | symbol attached | subjected to this recessed part for reflection, when it is necessary to distinguish with the recessed part for reflection which belongs to 14 A of 1st display patterns, and the recessed part for reflection which belongs to the 2nd display pattern part 14B, it is the former reflection. The concave portion for use is labeled “16 (A)”, and the concave portion for reflection is assigned the symbol “16 (B)”. "Is attached. Here, FIG. 4A shows the dot reflection concave portions 16A belonging to the first pattern display portion 14A, and FIG. 4B shows the dot reflection concave portions 16B belonging to the second pattern display portion 14B. 4A schematically shows the incident directions of light from the light sources 12A and 12B, respectively.

Each of the reflecting recesses 16 has an axis (conical axis before being divided into two) O that is perpendicular to the dot formation surface 6 of the light guide plate 1 and the side corresponding to the bottom of the cone is the dot formation surface 6. It is formed in a state where it is recessed from the dot forming surface 6 so as to open in the area. Therefore, the inner surface of each reflecting recess 16 is connected between a tapered surface 18 (a half surface of the side surface of the cone before being divided into two) 18 spread at an angle of 180 degrees with respect to the axis O, and both ends of the tapered surface 18. It is constituted by the plane 20. The tapered surface 18 is a curved surface that is inclined at a predetermined angle with respect to a direction perpendicular to the dot formation surface 6 of the light guide plate 1 and is curved in a plane parallel to the dot formation surface 6. The plane 20 is a plane perpendicular to the dot formation surface 6 of the light guide plate 1.
The tapered surface 18 corresponds to a reflecting surface for reflecting the light guided from the light source 12A or the light source 12B into the light guide plate 1 toward the pattern display surface 7, as will be described later. On the other hand, the plane 20 can correspond to a non-reflective surface that does not substantially guide light guided from the light sources 12A and 12B into the light guide plate 1 toward the pattern display surface 7 by reflection or refraction.

Here, the direction of the taper surface (reflection surface) 18 is different between the first display pattern portion 14A and the second display pattern portion 14B.
That is, as schematically shown in the upper right side of FIG. 1 and FIG. 4A, in the reflective concave portion 16 (A) constituting a large number of dots belonging to the first display pattern portion 14 A, the tapered surface 18 is formed. The convex curved side of the taper surface 18 faces the second light source 12B in the concave portion 16 (B) for reflection that constitutes a large number of dots belonging to the second display pattern portion 14B. It is prescribed as follows.

  The taper angle 18 of the tapered surface 18 on the inner surface of the reflecting concave portion 16 (the angle of the side surface with respect to the vertical axis O in the right circular cone before the division into two) θ is a plane orthogonal to the axis O (therefore, dot formation of the light guide plate 1 It is determined so that light incident on the tapered surface 18 along a plane parallel to the plane 6 can be reflected toward the pattern display plane 7 (preferably in a direction perpendicular to the pattern display plane 7 or at an angle close thereto). Although it is not particularly limited, the angle is generally set to 45 degrees or an angle within a range of about 30 to 60 degrees close thereto.

In the above embodiment, red light is incident on the light guide plate 1 through the end face 5 from the first light source 12A composed of the plurality of light emitting elements 12A _{1 to} 12A ₄ and at the same time, the plurality of light emitting elements 12B _{1 to} 12B _4. A situation when blue light is incident on the light guide plate 1 through the end face 3 from the second light source 12 </ b> B composed of the above will be described below.

  If the red light from the first light source 12A reaches the tapered surface (reflective surface) 18 of a large number of dots (reflective recess 16 (A)) belonging to the first display pattern portion 14A, the red light is Reflected by the taper surface 18 toward the pattern display surface 7, the pattern of the first display pattern portion 14 </ b> A (character pattern “A”, “B”, “C”) is formed by an aggregate of these many dots. It emits red light and is displayed. On the other hand, if the blue light from the second light source 12B reaches the tapered surface (reflective surface) 18 of the dot (reflective recess 16 (B)) belonging to the second display pattern portion 14B, the red light is Reflected by the taper surface 18 toward the pattern display surface 7, the pattern of the second display pattern portion 14 </ b> B (“D”, “E”, “F” character patterns) is formed by an aggregate of these many dots. Emits blue light and is displayed.

At this time, the red light from the first light source 12A also reaches the flat surface (non-reflective surface) 20 in the dots (reflective recess 16 (B)) belonging to the second display pattern portion 14B. However, since the red light incident on the plane 20 is not reflected toward the pattern display surface 7 and is not guided toward the pattern display surface 7 due to refraction, the red light is emitted on the pattern display surface 7. In addition, the second display pattern portion 14B does not produce a mixed color of blue and red.
Conversely, the blue light from the second light source 12B also reaches the flat surface (non-reflective surface) 20 in the dot (reflective recess 16 (A)) belonging to the first display pattern portion 14A. However, since the blue light incident on the plane 20 is not reflected or refracted toward the pattern display surface 7, no blue light is emitted on the pattern display surface 7, and the first display pattern portion 14A mixes blue and red. Does not occur.
Accordingly, the first display pattern portion 14A and the second display pattern portion 14B can display respective patterns with clearly different emission colors.

Furthermore, in the present embodiment, it is possible to prevent the occurrence of uneven stripes regardless of the first display pattern portion 14A and the second display pattern portion 14B.
In other words, the reflecting surface (tapered surface) 18 of the reflecting recess 16 is formed by a surface that forms a part of the side surface (conical surface) of a right cone, and thus is in a plane orthogonal to the axis O (that is, guided). All the light reaching the reflecting surface 18 from various directions (in the plane parallel to the dot forming surface 6 of the optical plate 1) is reflected in one direction parallel to the axis O, that is, one direction perpendicular to the dot forming surface 6. Is done.
Specifically, in the case of the present embodiment, the first light source 12A that emits red light includes four light emitting elements 12A ₁ , 12A ₂ , 12A ₃ , 12A ₄ in one direction on the end surface 5 of the light guide plate 1. For this reason, on the reflecting surface (tapered surface) 18 of the dot reflecting recess 16 (A) constituting the character pattern (for example, the letter “B”) of the first display pattern portion 14A. In this case, red light is incident from different directions for each light emitting element, but all light from any light emitting element is reflected in one direction parallel to the axis O, that is, one direction perpendicular to the dot formation surface 6. The
Therefore, the reflection image from each reflection surface 18 viewed from the pattern display surface 7 side is almost the same as the shape of the reflection surface 18 projected onto the pattern display surface 7, and there is a reflection image as in the prior art. It will not be stretched in the direction. Therefore, even if the adjacent reflecting recesses 16 are close to each other, there is little possibility that the sales company images from the reflection surfaces of the adjacent reflecting recesses 16 will be continuous, and therefore streaky irregularities appear. Can be suppressed.

FIG. 5 shows a display device according to a second embodiment of the present invention.
The display device according to the second embodiment is for displaying patterns such as predetermined symbols and characters in four different colors on one pattern display surface.

In FIG. 5, light emitting elements 12 </ _b > A ₁ , 12 </ _b > A ₂ , 12 </ _b > A that emit a plurality of (four in the illustrated example), for example, red light, such as LEDs, are formed on one end surface 5 of the light guide plate 1 along the length direction. ₃ and 12A ₄ are arranged, and these 12A ₁ to 12A ₄ constitute the first light source 12A. Further, on the end surface 3 opposite to the end surface 5 in the light guide plate 1, a plurality (four in the illustrated example) of light emitting elements 12B ₁ to 12 that emit blue light such as LEDs along the length direction thereof. 12B ₄ and is arranged, by these _12B 1 _{~12B 4,} the second light source 12B is configured. Further, the end face 4 adjacent to the end face 5 in the clockwise direction has a plurality of (four in the illustrated example) light emitting elements 12C ₁ to 12 such as LEDs that emit green light along the length direction thereof. 12C ₄ and is arranged, by these _12C 1 _{~12C 4,} a third light source 12C is configured. Further, a plurality of (four in the illustrated example) light emitting elements 12D ₁ that emit yellow light such as LEDs along the length direction of the end face 2 that is adjacent to the end face 3 in the clockwise direction. To 12D ₄ are disposed, and the fourth light source 12D is configured by these 12D ₁ to 12D ₄ .

Of the two plate surfaces 6 and 7 of the light guide plate 1, one plate surface 6 (the back side surface in FIG. 7) is a dot forming surface and the other plate surface 7 (the front side surface in FIG. 7). Is a pattern display surface.
On the dot forming surface 6, the first display pattern portion 14 </ b> A for emitting red light from the first light source 12 </ b> A to display a predetermined pattern on the pattern display surface 7 with red light, and the second A second display pattern portion 14B for emitting a predetermined pattern on the display surface 7 by blue light from the light source 12B and a green light from the third light source 12C. The third display pattern portion 14C for displaying the pattern on the display surface 7 with green light and the yellow light from the fourth light source 12D emit light and display the predetermined pattern on the display surface 7 with yellow light. For this purpose, a fourth display pattern portion 14D is formed.
Each of the first to fourth display pattern portions 14A to 14D is formed by forming a pattern such as a picture, a character, a symbol, or a pattern by an aggregate of a large number of dots each composed of a concave portion 16 for reflection. In the embodiment, the first display pattern portion 14A is formed with uppercase alphabetic characters “A” and “B” by dots, and the second display pattern portion 14B is formed with uppercase alphabetic characters. "E" and "F" character patterns are formed by dots, and the upper-case alphabetic characters "C" and "D" are formed by dots in the third display pattern portion 14C. In the fourth display pattern portion 14D, uppercase alphabetic character patterns “G” and “H” are formed by dots.

As shown schematically in FIGS. 6 (A) and 6 (B), the large number of dots constituting each of the display pattern portions 14A to 14D has a right cone and two planes including its axis O (which are orthogonal to each other). In this case, it is constituted by a concave portion (reflective concave portion) 16 having the shape of one divided body, that is, the shape of a quadrangular cone. Each reflecting recess 16 has its axis (rotating axis of the cone before being divided into four) O perpendicular to the dot forming surface 6 of the light guide plate 1 and the side corresponding to the bottom surface of the cone is dot forming. It is formed in a state of being recessed from the surface 6 so as to open to the surface 6. Therefore, the inner surface of each reflecting recess 16 has a tapered surface 18 ′ (a surface that is a quarter of the side surface of the cone before being divided into four) 18 ′ widened at an angle of 90 degrees with respect to the axis O, and the tapered surface 18 ′. That is, it is constituted by two planes 20A and 20B connecting between both end edges and the axis O. The tapered surface 18 ′ is inclined at a predetermined angle with respect to the direction perpendicular to the dot formation surface 6, and the planes 20 A and 20 B are surfaces perpendicular to the dot formation surface 6.
The tapered surface 18 ′ is configured to reflect the light guided through the light guide plate 1 from the light sources 12 </ b> A to 12 </ b> D toward the pattern display surface 7, as in the case of the first embodiment. It corresponds to a surface. The planes 20 </ b> A and 20 </ b> B correspond to the non-reflecting surfaces that do not substantially guide the light guided from the light sources 12 </ b> A to 12 </ b> D into the light guide plate 1 toward the pattern display surface 7.

Here, the direction of the tapered surface (reflective surface) 18 'is different for each of the display pattern portions 14A to 14D.
That is, as schematically shown in the positions of the four corners in FIG. 5, in the concave portion for reflection 16 (A) constituting a large number of dots belonging to the first display pattern portion 14A, the convex curvature of the tapered surface 18 ′ is formed. In the reflective concave portion 16 (B) that constitutes a large number of dots belonging to the second display pattern portion 14 B, the convex curved side of the tapered surface 18 ′ faces the second light source 10 B, and the first light source 10 A faces the first light source 10 A. In the reflective concave portions 16 (C) constituting a large number of dots belonging to the third display pattern portion 14C, the convex curved side of the tapered surface 18 'faces the third light source 10C, and a large number of the concave portions belonging to the fourth display pattern portion 14D. In the reflective concave portion 16 (D) constituting the dot, the convex curved side of the tapered surface 18 ′ is determined so as to face the fourth light source 10 </ b> D.

  In the second embodiment as described above, the situation when red light, blue light, green light, and yellow light are incident on the light guide plate 1 from the light sources 12A to 12D will be described below.

The reflective concave portion 16 (A) constituting the dots of the first pattern display portion 14A has a tapered surface because the convex curved surface side of the tapered surface 18 'faces the first first light source 12A. 18 ′ reflects the red light from the first light source 12 </ b> A toward the pattern display surface 7. On the other hand, the other light sources 12B, 12C, and 12D are not directed to the convex curved surface side of the tapered surface 18 ′ of the reflective recess 16 (A) of the first pattern display portion 14A. Blue light, green light, and yellow light from 12D are not guided toward the pattern display surface 7. Further, the planes 20A and 20B of the reflective recess 16 (A) of the first pattern display portion 14A do not substantially guide light from the light sources 12A to 12D toward the pattern display surface 7.
Therefore, the first pattern display unit 14A emits and displays a predetermined pattern (a character pattern of “A” and “B”) in red without mixing light of other colors with red light. Similarly, in the other pattern display portions 14B, 14C, and 14D, color mixing occurs due to the blue light, the green light, and the yellow light from the light sources 12B, 12C, and 12D on the side where the tapered surface of the reflective concave portion faces. Instead, it is possible to display the pattern in a predetermined light emission color.
Also in the case of the second embodiment, the occurrence of streak unevenness can be suppressed as in the first embodiment.

  As described above, in the first embodiment, the light guide plate 10 has a rectangular shape, light sources having different emission colors are disposed on the two end faces, and the two display pattern portions emit light in different colors. In the second embodiment, the light guide plate 10 is also rectangular, and light sources having different emission colors are arranged on the four end faces thereof, so that the four display pattern portions emit light in different colors. Light sources of different emission colors are arranged on three end faces of the four end faces of the rectangular light guide plate so that the direction of light incident on the light guide plate from each light source is shifted by 90 degrees, Of course, three display pattern portions may be formed on the pattern display surface, and these three display pattern portions may emit light in different colors. In this case, the reflecting concave portion may have an inner surface shape obtained by dividing the right cone into four parts as in the second embodiment.

  Further, the light guide plate 10 is formed into a triangular shape when viewed in plan, and light sources of different emission colors are arranged on the three end faces, and the three display pattern portions are displayed in different colors on the triangular pattern display surface. It may be configured to emit light. In this case, if the light guide plate is an equilateral triangle, the reflecting concave portion may have a shape of a three-piece cone formed by dividing a right cone into three equal parts by a plane including its axis. In addition, using a pentagonal or more polygonal light guide plate or a disc-shaped light guide plate, a plurality of light sources are arranged at different locations on each end face or outer peripheral surface, and dots of each display pattern portion are configured. The reflecting concave portion may have a shape having a tapered surface constituting a part of the conical surface, and the concave and convex curved surface side of each tapered surface may be directed to the corresponding light source.

  In each of the above-described embodiments, the aggregate of dots corresponding to each display pattern portion is formed separately from each other on the plate surface of the light guide plate, but depending on the case, it corresponds to each display pattern portion. Part or all of the dot aggregate may overlap on the plate surface of the light guide plate. An example thereof is shown in FIG. 7 in accordance with FIG. 1 showing the first embodiment. In this case, a pattern (“A”, “B”, “C”) that is lit and displayed on the first pattern display section 14A and a pattern (“D”) that is lit and displayed on the second pattern display section 14B. , “E”, “F”) partially overlap, and color mixing occurs in the overlapping part, but each light emission color is appropriately selected so that appropriate color mixing occurs in the overlapping part. If set to, it is possible to increase the number of emitted colors to be displayed rather than the number of emitted colors by the light source, and display in various color tones.

  Furthermore, in each of the above-described embodiments, each light source emits light of a different color, but the light emission colors of each light source need not be all different colors. For example, all the light emission colors of a plurality of light sources are made the same color, or the light emission colors of two or more light sources of a part of the plurality of light sources are made the same color so that each light source blinks and The timing may be controlled to be different between at least light sources of the same color. In this case, even if two or more pattern display units emit the same color, the pattern display units display the light emission at different timings. Even when such a control method is applied, the present invention is also applicable. Is valid.

  Further, as shown in FIG. 7, when the light emission colors of the respective light sources are made different, and when part or all of the respective display pattern portions are overlapped, the respective light sources blink, and the blinking If the timing is controlled to be different, it is possible to avoid the occurrence of color mixing in the portion where the patterns overlap. Furthermore, various display modes can be obtained by appropriately combining the light emission timing control and the light emission color setting.

  Here, in each of the above-described embodiments, the shape of the inner surface of the reflecting recess 16 is a shape obtained by dividing the right cone into two or three or more divided into three or more, and a plane (non-reflective surface) corresponding to the divided surface. Is configured to be perpendicular to the dot forming surface 6 of the light guide plate 1, but a non-reflective surface other than the tapered surface 18 serving as a reflective surface (the flat surface 20 in the first embodiment, the second implementation). The planes 20 </ b> A and 20 </ b> B are not necessarily perpendicular to the dot formation surface 6. That is, the non-reflective surface other than the tapered surface 18 to be the reflective surface among the inner surfaces of the reflective recesses 16 is essentially the light guided from each light source substantially reflected toward the pattern display surface 7 by reflection or refraction. From this point of view, the non-tapered surface should be a plane slightly inclined toward the convex curve side of the tapered surface 18 rather than a surface perpendicular to the dot formation surface 6. Is preferred. For example, reflection in which the flat surface (non-reflective surface) 20 in the concave portion for reflection (conical bipartite shape) shown in FIG. 4A shown as the first embodiment is inclined from a surface perpendicular to the dot formation surface 6. An example of the concave portion 16 for use is shown in FIGS.

8 (A) and 8 (B), the reflecting recess 16 has a right cone formed by a plane 20 along a straight line M that passes through the apex P of the right cone and is inclined with respect to the axis O by a small angle φ. Cut the apex angle ρ,
ρ = θ−φ
It is set as the shape of the right cone non-uniform division body. In this case, the light (black arrow) that has arrived from the opposite direction to the tapered surface (reflecting surface) 18 is reflected toward the dot forming surface 6 by the inclined flat surface 20, and thus the pattern display surface 7. Thus, it is possible to reliably avoid the reflected light from reaching. Therefore, it is possible to more reliably prevent color mixing in each pattern display unit. However, from the viewpoint of processing of the light guide plate for forming the reflective recess, the process of forming the reflective recess 16 is more preferable when the plane (non-reflective surface) 20 is a vertical surface as in the embodiment described above. However, when the processing cost is important, it is desirable that the flat surface (non-reflective surface) 20 be a vertical surface.

  Further, as shown in FIGS. 9A and 9B, the reflective recesses (see FIGS. 6A and 6B) applied to the display device of the second embodiment shown in FIG. Non-reflective surfaces other than the tapered surface 18 'that is a surface, that is, the flat surfaces 20A and 20B may be inclined surfaces.

Furthermore, as shown in FIG. 10, the shape of the inner surface of each reflecting recess 16 may be a shape obtained by dividing a truncated cone into two vertically divided by a surface including the axis O. Here, the truncated cone means a portion on the bottom surface side when a right cone is cut along a plane parallel to the bottom surface. Even in the case of the reflective concave portion 16 having an inner surface with a shape obtained by dividing the truncated cone into two vertically, the portion of the tapered surface 18 is a reflective surface, and the convex curved surface side is directed to the corresponding light source, Similar to the embodiment shown in FIGS. 1 to 4, it is possible to prevent color mixing and to prevent streaking.
Also in the case of such a truncated cone shape, the flat surface (non-reflective surface 20) other than the tapered surface 18 may be an inclined surface as shown in FIG.

  In addition, various curved surfaces can be applied as the shape of the inner surface of the concave portion for reflection, particularly the shape of the tapered surface (reflective surface). For example, as the inner shape of the concave portion for reflection, as shown in FIG. A surface corresponding to a part of the outer peripheral surface of the right circular cylinder by applying a shape in which the axis O is inclined by a predetermined angle α from the direction Q perpendicular to the dot forming surface of the light guide plate and a part of the right circular cylinder is cut off. May be a reflective surface (tapered surface) 18 and one of the cut surfaces may be a non-reflective surface 20.

  In addition, as shown in FIG. 12, the oblique cone obtained by inclining the right cone axis O from the direction Q perpendicular to the dot formation surface of the light guide plate by a predetermined angle β is divided into two (or 3) by the plane including the axis 0. The reflecting concave portion 16 may be formed by a shape that is divided into multiple parts or more. Further, although not shown in the drawings, a similar oblique cone may be divided into two (or more than three divisions) by a plane perpendicular to the dot formation surface of the light guide plate.

  The light guide plate generally has a uniform thickness (a distance between the dot formation surface and the pattern display surface), but the thickness may be changed depending on circumstances. For example, the pattern display surface is slightly inclined with respect to the dot formation surface so that the thickness increases from one end surface of the light guide plate to the opposite end surface, or a step is provided in the middle of the pattern display surface. Also good. Furthermore, the planar overall shape of the light guide plate may be any shape other than the square shape, the triangular shape, the polygonal shape, and the circular shape as described above. Further, even in the case of a square shape, the shape is not limited to a square, and may be a rectangle. In particular, two parallel sides (two end surfaces) are significantly longer than two sides (two end surfaces) that are perpendicular to the two sides, and are square bars or close to them. It can also be a shape.

  Furthermore, the end surface of the light guide plate does not necessarily have to be perpendicular to the plate surface, particularly the dot display surface, but in order for light from the light source to enter the light guide plate in a direction parallel to the dot formation surface. It is preferable that at least the end surface on the side where the light source is disposed be perpendicular to the dot formation surface.

  Further, in each of the above-described embodiments, each light source is configured by a plurality of light emitting elements, and the plurality of light emitting elements belonging to each light source are disposed on one end surface of the light guide plate along the length direction of the end surface. Each light source is composed of one or more linear light sources each having a certain length, and the linear light sources are arranged on the end face of the light guide plate along the length direction of the end face. Also good. Even when such a linear light source is used, as described above, streak unevenness is likely to appear in the prior art, but in the case of the present invention, the appearance of streak unevenness can be suppressed even in that case.

  Although preferred embodiments of the present invention have been described above, the present invention is of course not limited to these embodiments. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Light guide plate, 2, 3, 4, 5 ... End surface, 6 ... Plate surface (dot formation surface), 7 ... Plate surface (Pattern formation surface, 12A, 12B, 12C, 12D. ..Light source, 14A, 14B, 14C, 14D ... display pattern, 16, 16 (A), 16 (B), 16 (C), 16 (D) ... reflective recess, 18 ... taper Surface (reflective surface), 20, 20A, 20B ... plane (non-reflective surface).

Claims (7)

A light guide plate made of a transparent material and having a plurality of display pattern portions each formed of an aggregate of a large number of dots on one of the two plate surfaces;
A plurality of light sources for making light incident in different directions along the one plate surface of the light guide plate from the end surface side of the light guide plate into the light guide plate,
Each dot constituting the plurality of display pattern portions is constituted by a reflective concave portion that is recessed from the one plate surface of the light guide plate, respectively.
In addition, the reflection concave portion of each dot is formed by a tapered surface in which a part of the inner surface is inclined with respect to a direction orthogonal to the one plate surface and curved in a plane parallel to the one plate surface. The tapered surface is a reflecting surface that reflects light from any one of the plurality of light sources toward the other plate surface,
Furthermore, among the inner surfaces of the reflective recesses of each dot, the surface other than the tapered surface is configured not to substantially guide the light from each light source to the other plate surface,
The convex curved side of the tapered surface of the reflecting concave portion constituting the dot is directed toward a different light source for each display pattern portion to which the dot belongs, and reflects light from a different light source toward the other plate surface. A display device characterized by being configured to do so.   The display device according to claim 1, wherein a surface other than the tapered surface is a surface perpendicular to the one plate surface.   The surface other than the tapered surface is a surface that is inclined with respect to the one plate surface, and the inclination direction is determined in a direction that does not reflect or refract light from each light source toward the other plate surface. The display device according to claim 1, wherein the display device is a display device.   The taper surface is a surface having a shape corresponding to a part of a side surface of a right cone having an axis perpendicular to the one plate surface. The display device according to claim.   The inner surface of each of the reflecting recesses is formed in the shape of one divided cone when the right cone is divided by one or more planes including its rotation axis. 4. The display device according to 4.   5. The reflection concave portion is made in the shape of one divided truncated cone when the truncated cone is divided by one or more planes including the rotation axis thereof. The display device described. The at least one light source among the plurality of light sources is configured by a plurality of light emitting elements arranged in a direction along an end surface of the light guide plate. The display device according to claim.

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