JP2014203604A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which is suitable for improving the luminance uniformity of a light emitting face of a lighting device.SOLUTION: This lighting device comprises a plurality of light sources (1), and a shade (3) as a shield case which has transparency, and diffuses and emits light from the light sources. An optical member (2) in which a plurality of optical elements (21) having lens shapes for refracting the light from the light sources are two-dimensionally aligned is arranged between a plurality of the light sources (1) and the shade (3), and emission light from the light sources (1) is radiated to the shade (3) via the optical elements (21). The optical elements (21) are arranged in a plurality of numbers so as to correspond to a plurality of the light sources (1), respectively.

Description

  The present invention relates to an illumination device such as a ceiling light.

  In a lighting device such as a ceiling light or base illumination using, for example, an LED (Light Emitting Diode) as a light source, it is made of a material such as a resin having transparency called a shade that becomes an exterior case on the light irradiation side of the lighting device. It has a member. The seed is a member serving as an irradiation surface of the lighting device, and has a function of transmitting light from a light source mounted on the lighting device while diffusing. The light transmitted through the shade and emitted is used as illumination light of the illumination device to illuminate a predetermined range or region.

  In such an illuminating device, for example, a ceiling light, it is desirable that an extreme brightness and darkness in which a portion at a position corresponding to the light source on the shade does not increase in brightness locally, that is, a uniform illuminance distribution is obtained. .

  As a conventional technique for obtaining a uniform illuminance distribution, for example, one described in Patent Document 1 is known. In Patent Literature 1, in a lighting device including a substrate on which a plurality of directional light sources are mounted, a diffusion plate is disposed so that light is uniform on the substrate and diffuses light from the light source. It discloses that the occurrence of light and darkness on the diffusion plate due to the arrangement of the light sources is suppressed by arranging the distance from the light source to the diffusion plate to be larger than the distance between the plurality of light sources.

Japanese Patent No. 4996998

  In the configuration described in Patent Document 1, it is necessary to ensure that the distance between the diffusion plate and the light source is larger than the arrangement pitch of the light sources. In this case, the thickness of the lighting device (dimension in the direction orthogonal to the irradiation surface of the lighting device) increases, and it becomes difficult to realize a small and thin lighting device. In order to shorten the distance between the diffuser plate and the light source, an attempt to shorten the arrangement pitch of the light sources requires a large number of light sources, resulting in problems of increased heat generation, the number of parts and cost. Further, if the light diffusion degree of the diffusion plate is increased in order to improve the uniformity of the illuminance distribution of the illumination light, the transmittance of the diffusion plate is reduced, so that the luminance and luminous efficiency of the illumination light are reduced.

  The present invention has been made in view of the above-described problems of the prior art, and in an illumination device including a plurality of light sources, the brightness of the illumination light and the illuminance uniformity are suppressed while suppressing an increase in the thickness of the illumination device and the number of light sources. The present invention provides a suitable technique for improving the performance.

  The present invention is characterized by, for example, the structures described in the claims. More specifically, an illuminating device according to the present invention includes a plurality of light sources and a shade as an exterior case that has translucency and diffuses and emits light from the light sources. The optical member includes a plurality of optical elements that are arranged between the plurality of light sources and the shade and have a lens shape that refracts light from the light sources and is two-dimensionally arranged. The number of optical elements arranged is larger than the number of the light sources, and the shade is irradiated with light emitted from the light sources via the optical elements.

  According to the configuration of the present invention, a plurality of pseudo light-emitting portions (light-emitting regions) larger than the number of light sources on the optical member are refracted by each optical element and emitted from the light beam from the light source. It is possible to form a light flux having a uniform brightness spatially and incident on the shade. Therefore, according to the present invention, it is possible to provide an illuminating device capable of improving the illuminance uniformity on the shade and suppressing the increase in the thickness of the illuminating device and the number of light sources, and obtaining bright illumination light. Is possible.

The disassembled perspective view which shows one structural example of the illuminating device which concerns on 1st Example of this invention. Sectional drawing of the illuminating device which concerns on a 1st Example. The figure which shows an example of the optical element 21 of a 1st Example. The figure which shows the other example of the optical element 21 of a 1st Example. Sectional drawing which shows one structural example of the illuminating device which concerns on 2nd Example of this invention. The figure explaining the optical effect | action of 2nd Example Sectional drawing which shows one structural example of the illuminating device which concerns on 3rd Example of this invention. FIG. 6 is a diagram showing a first example of arrangement of optical elements in the optical member 2 according to the fourth embodiment of the present invention. FIG. 9 is a diagram showing a second example of the arrangement of the optical elements in the optical member 2 according to the fourth embodiment of the present invention. FIG. 6 is a diagram showing a third example of the arrangement of the optical elements in the optical member 2 according to the fourth embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each figure, elements having the same function and configuration are denoted by the same reference numerals, and redundant description is omitted.

  First, the configuration of the first embodiment of the present invention will be described with reference to FIG. Here, FIG. 1 shows an exploded perspective view of the illumination device according to the first embodiment. Hereinafter, as a lighting device according to the present embodiment, a ceiling light is taken as an example to describe the present embodiment.

  As shown in FIG. 1, the illumination device according to the present embodiment includes a plurality of light sources 1, a light source substrate 10 on which the plurality of light sources 1 are mounted, an irradiation surface of the illumination device, and the illumination device. A shade 3 having translucency and light diffusibility, which is an exterior case on the light irradiation side, is provided. The upper side of the drawing is the light irradiation direction (light irradiation side) of the illumination device according to the present embodiment. The shade shown in FIG. 1 has a planar shape, but may have a shape curved with a convex toward the light irradiation side.

  In this embodiment, an optical member 2 in which a plurality of optical elements 21 are two-dimensionally formed is disposed between the light source 1 and the shade 3. The optical member 2 is a plate-like member made of, for example, a transparent resin, and has a plurality of optical elements that form, for example, convex lenses on the front surface (the shade 3 side), the back surface (the light source 1 side), or both surfaces thereof. 21 is formed.

  The light source substrate 10 and the optical member 2 are housed in a side cover 5 that is a cylindrical outer case that covers the periphery of the side surface of the lighting device, and fixed at predetermined positions by screws, pins, engaging parts, or the like. The shade 3 is coupled or engaged with the light irradiation side end of the cylindrical side cover 5. A power supply unit 4 is connected to the back side of the light source substrate 10, and power from the power supply unit 4 is supplied to each light source 1 through a wiring pattern formed on the light source substrate 10.

  In addition, since the illumination device according to the present embodiment has a circular irradiation surface, the shape of the shade 3, the optical member 2, the light source substrate 10, and the side bar 5 viewed from the light irradiation side is circular. It is not limited. The shape viewed from the light irradiation side may be a rectangle such as a square, or may be a polygon such as a hexagon. Further, in this embodiment, the exterior case is composed of the shade 3 which is the exterior case on the irradiation surface side and the side cover 5 which is the exterior case on the side surface, but the shade 3 is convex toward the light irradiation side. If the optical member 2 is housed inside the optical member 2 and configured to be coupled to the light source substrate 10, the shade 3 can be used also as the side cover 5. In this case, the side cover 5 Is no longer necessary.

  In the present embodiment, the light source 1 is, for example, a light emitting diode (LED), and emits a light flux so that the peak of light emission is directed to the optical member 2 disposed so as to face the light emitting surface thereof. In this embodiment, for example, a white LED that emits white light can be used as the LED. The white LED includes, for example, a light emitting chip portion that emits blue light when receiving power, a phosphor that is excited by receiving blue light from the light emitting chip, and emits light having a spectrum in a wavelength range from green to red. have. As this phosphor, a phosphor having an emission spectrum that appears to be yellow by exciting red and green light simultaneously can be used. Further, in one LED, a large light quantity type LED on which a plurality of light emitting chips are mounted may be used. In an LED equipped with a plurality of light emitting chips, it is preferable to arrange the light emitting chips in, for example, a rectangular shape or a concentric circle so that they are symmetrical with respect to the center of the light emitting surface (light emitting surface) of the LED. It is not limited to this.

  The light source 1 may be provided with light adjusting components such as a lens and a reflector for improving light distribution adjustment and light extraction efficiency. As such a light adjusting component, for example, a convex lens formed of a transmissive material, a metal-deposited mirror, or the like can be used.

  A plurality of light sources 1 are two-dimensionally mounted on the surface of the light source substrate 10 on the shade 3 side. Although FIG. 1 illustrates an example in which five light sources 1 are mounted on the light source substrate 10, the number of light sources mounted may be changed as necessary. When the light source 1 is two-dimensionally mounted on the light source substrate 10, the light source 1 may be arranged concentrically with respect to the center of the light source substrate 10, or may be arranged so as to form a rectangle. However, they may be arranged radially. Furthermore, the arrangement of the light sources 1 may be a geometrically symmetrical arrangement or a staggered arrangement. An arrangement in which the light source 1 is added at the center or the periphery of the light source substrate 10 may be used, and the arrangement of the light source 1 does not limit the present invention.

  In addition to the light source 1, the light source substrate 10 generates a drive voltage for driving the light source 1 based on the power supply from the power supply unit 4 and supplies it to the light source 1, wiring, and / or Electronic components such as a control circuit for controlling the power supply amount (current amount) to the light source 1 and an electric circuit are provided. These electronic components and electric circuits may be provided on the surface of the light source substrate 10 opposite to the mounting surface of the light source 1.

  Here, it is desirable that the optical characteristics of the surface of the light source substrate 10 (the surface on the shade 3 side) have a high reflectance with little light absorption. The optical member 2 is made of a transparent material, but the light beam emitted from the light source 1 and incident on the optical member 2 transmits all the light beams because of Fresnel reflection generated at the interface between the optical member 2 and air. I can't let you. In the illuminating device, ideally, it is desirable that all the light rays from the light source 1 pass through the optical member 2, so that the light rays that have not been transmitted by Fresnel reflection enter the optical member 2 again. In the present embodiment, a highly reflective material is provided on the surface of the light source substrate 10 so that the light beam reflected at the interface between the optical member 2 and the air is incident again on the optical member 2. This can be realized, for example, by applying a white paint (ink) to the surface of the light source substrate 10. As a result, the surface on the light source substrate 10 has a reflection characteristic, and the light beam reflected by the optical member 2 and returning to the light source 1 side (light source substrate 10 side) is directed again toward the optical member 2 on the surface of the light source substrate 10. Can be reflected. In the above example, the white paint is applied to the surface of the light source substrate 10 in order to give the surface of the light source substrate 10 reflection characteristics. However, a white reflection sheet or reflection film is arranged or laminated on the surface of the light source substrate 10. It may be. Moreover, the structure which exposed the metal glossy surface with little absorption to the light source substrate 10 may be sufficient, and also the light source substrate 10 may be mirror-finished.

  The light source substrate 10 may be made of a metal such as aluminum having good heat dissipation. If the power supplied to the light source substrate 10 is small and heat dissipation is not important, the light source substrate 10 may be made of a material other than metal, such as glass epoxy resin.

  The optical member 2 is made of a transparent material having optical transparency such as glass or plastic. As the transparent material, for example, polycarbonate, acrylic, or the like can be used when a plastic having excellent productivity is taken as an example. As a method of manufacturing the optical member 2, for example, injection molding can be used in which a transparent resin such as acrylic is heated to increase the fluidity and poured into a mold, which is cooled and solidified. At this time, it is preferable that the surface of the mold for molding the light incident surface and the light emitting surface of the optical member 2 is polished.

  The optical element 21 formed on the optical member 2 has a shape that refracts or reflects light from the light source 1. The shape is typically a convex lens shape. Moreover, as a shape of the optical element 21, you may be comprised by the spherical surface, the plane, or another kind of curved surface, for example. As shown in FIG. 1, a plurality of optical elements 21 (30 in the example of FIG. 1) are provided on the optical member 2 for one light source 1. That is, a plurality of optical element groups 21 are provided corresponding to each of the plurality of light sources 1.

  As a method for manufacturing the optical element 21, there is, for example, injection molding using a mold. If the shape of the optical element 21 is engraved in a mold for injection molding the optical member 2, the optical element 21 can be integrally molded on the surface of the optical member 2. In this manufacturing method, since the optical member 2 and the optical element 21 can be integrally formed, the manufacturing process is relatively reduced, and the manufacturing cost can be suppressed.

  As another manufacturing method, there is a method in which the optical element 21 is manufactured as a sheet-like member different from the optical member 2 and attached to the front surface, the back surface, or both of the optical member 2. When the optical element 21 has a complicated shape, molding may be difficult by injection molding using a mold. In injection molding, when the thickness of a molded product is large, it shrinks when it cools and hardens. The fine shape has a problem that the shape is distorted by the contraction. Therefore, in the case where the optical element 21 has a fine and complicated shape, a method of forming the optical element 21 on the surface of a thin sheet is effective. The sheet on which the optical element 21 is formed needs to be attached to the optical member 2 in order to maintain the shape. The adhesive used for pasting is transparent, and its refractive index is preferably an intermediate value between the optical member 2 and the optical element 21. This is because the difference in refractive index between different media causes reflected light to be generated at the interface between the two media. That is, if it is said structure, the reflected light which generate | occur | produces in the interface of the adhesive agent pinched | interposed between the optical member 21 and the optical member 2 can be suppressed, and the transmittance | permeability can be raised. For this reason, the light beam emitted from the light source 1 can be efficiently transmitted through the optical member 2 and the optical member 21, and the amount of light incident on the shade 3 can be increased.

  The light emitted from the light source 1 is refracted or reflected by the optical element 21 formed on the optical member 2 and enters the shade 3. The optical action of the optical element 21 formed on the optical member 2 will be further described with reference to FIG.

  FIG. 2 shows a cross section orthogonal to the irradiation surface of the illumination apparatus according to the present embodiment. In this example, three optical elements 21 a to 21 c are formed on the optical member 21 for one light source 1, and each optical element 21 a to 21 c is convex toward the light source 1 (light source substrate 10) side. It is assumed that it has a spherical biconvex lens shape including a spherical incident surface 211 and a spherical exit surface 212 convex toward the shade 3 side. In the example of FIG. 2, the number of the optical elements 21 is three, but it is needless to say that the number of optical elements 21 may be different from that of the light source 1.

  In the example shown in FIG. 2, the optical path of the light beam emitted from the light source 1 is separated for each light beam incident on the optical elements 21a, 21b, and 21c. Specifically, the light beam incident on the incident surface 211 of the optical element 21a is refracted on the surface. The light beam refracted by the incident surface 211 of the optical element 21a is refracted again by the output surface of the optical element 21a. As a result, of the light beams emitted from the light source 1, the light beam incident on the optical element 21a is emitted toward a certain area on the shade (almost directly above the optical element 21a). Similarly, the light beam incident on the optical element 21b out of the light beam emitted from the light source 1 illuminates a region (almost directly above the optical element 21b) different from the region of the shade 3 where the light beam having passed through the optical element 21a has reached. The light beam incident on the optical element 21c illuminates a region (substantially directly above the optical element 21c) different from the region of the shade 3 where the light beams that have passed through the optical elements 21a and 21b have reached. Naturally, the ranges of the light beams irradiated onto the shade 3 by the respective academic elements 21a to 21c may partially overlap each other.

  According to the optical action of the optical elements 21a to 21c, the light beam emitted from the light source 1 is separated by the optical elements 21a to 21c provided on the optical member 2, and each optical element 21 is as if it were a plurality of light sources. Illuminate the shade 3 as follows. That is, each optical element 21 can function as a pseudo light source. In order to uniformly irradiate the shade 3, it is effective to arrange the light sources densely with respect to the distance between the shade 3 and the light source 1. Since the light beam is separated into a plurality of light beams by a plurality of optical elements 21 disposed on the optical member 2 corresponding to each of the light sources and arranged more densely than the interval between the light sources 1, the shade 3 is illuminated. The interval (distance) between the emitted light beams from the optical elements 21 irradiated onto the shade 3 can be made shorter than the interval (distance) between the light sources 1 arranged on the light source substrate 10. As a result, when the distance between the light source 1 and the shade 3 is constant, the shade 3 can be irradiated more uniformly than when the light beam from the light source 1 is directly irradiated onto the shade 3 without using the optical member 2.

  Here, an example of the shape of the optical element 21 provided in the optical member 2 will be described with reference to FIGS. 3 and 4. FIG. 3 shows an example of the shape of the optical element 21, and shows an enlarged view of a cross section of one optical element 21 including the center of the optical element 21 and perpendicular to the surface of the optical member 2. FIG. 4 shows another example of the shape of the optical element 21, and shows an enlarged view of a cross section of one optical element 21 including the center of the optical element 21 and perpendicular to the surface of the optical member 2. Yes.

  The optical elements 21 shown in FIG. 3 and FIG. 4 are respectively convex toward the light source 1 (light source substrate 10) and are incident toward the incident surface 211 on which light from the light source 1 is incident and convex toward the shade 4 side. This is a biconvex positive lens that has a light exit surface 212 that emits light and has convex faces on both the light incident side and the light exit side. Here, it is assumed that the center of the entrance surface 211 and the center of the exit surface 212 coincide with each other. In other words, each of the optical elements 21 shown in FIGS. 3 and 4 is composed of a semicircular incident side lens having an incident surface 211 and a semicircular exit side lens having an output surface 212. The optical axis of the side lens and the optical axis of the exit side lens coincide with each other.

  The optical element 21 shown in FIG. 3 is configured such that the focal point of the incident surface 211 substantially coincides with the exit surface 212 of the optical element 21 as shown. With such a configuration, the luminous flux incident on the exit surface 212 out of the luminous flux incident on the incident surface 211 increases, so that the transmission rate is increased and the transmission rate of the optical member 2 can be improved.

  At this time, assuming that the incident surface 211 (the diameter thereof) is sufficiently small and the distance between the light source 1 and the optical element 21 is sufficiently large with respect to the size of the incident surface 211, the light beam incident on the incident surface 211 is approximately. It becomes parallel light. The parallel light incident on the incident surface 211 of the optical element 21 converges at one point on the focal point of the incident surface 211. In the example shown in FIG. 3, since the focal point of the incident surface 211 is substantially coincident with the emission surface 212, the emitted light beam from the light source 1 is converged on the emission surface 212, and the pass rate (enters the optical element 21). The ratio of the emitted light beam to the light beam can be increased. However, since the light source 1 actually has a finite size, the light beam incident on the incident surface 211 is not a perfect parallel light beam but converges to a finite size on the output surface 212. In addition, when the size of the optical element 21 is not sufficiently small compared to the distance between the light source 1 and the optical element 21, the optical element 21 is incident on the optical element 21 as a divergent light beam. There is a tendency that the image of the light source 1 that has substantially converged on 212 is blurred. Therefore, in order to ensure a sufficient passing rate, it is desirable that the size (diameter) of the exit surface 212 is larger than the size at which the entrance surface 211 forms a light source image.

  Further, in another example of the optical element 21 shown in FIG. 4, the focal point of the exit surface 212 is configured to substantially coincide with the entrance surface 211 as illustrated. The optical operation of another example of the optical element 21 shown in FIG. 4 will be described below.

  Since the light beam emitted from the light source 1 propagates while diverging before reaching the incident surface 211 of the optical element 21, the illuminance distribution formed by the light beam from the light source 1 on the incident surface 211 is relatively uniform. It becomes. This light beam passes through the inside of the optical element 21 as shown by the solid line and the dotted line in FIG.

  Here, the lens having a configuration in which the focal point of the emission surface coincides with the incident surface has a function of forming a light distribution of the emitted light according to the spatial illuminance distribution on the focal point of the emission surface. Therefore, if the focal point of the exit surface 212 coincides with the entrance surface 212 as in this example, the illuminance distribution on the entrance surface 211 is substantially uniform as described above, and thus the exit light from the exit surface 212 is substantially uniform. Have a good light distribution. At this time, the intensity of the emitted light beam from the optical element 21 becomes substantially constant without depending on the emission angle (outgoing direction). As a result, if the light source 1 can be seen through the optical element 21, the optical element 21 appears to emit light regardless of the direction, so that it can be seen that the light sources 1 are densely arranged. Therefore, according to the optical element 21 according to the present example, the light from the light source 1 can be irradiated so that the illuminance distribution on the shade 3 is uniform, and the passage rate is improved while improving the illuminance distribution on the shade 3. A high optical system can be provided.

  Thus, according to the present embodiment, a plurality of light sources arranged more densely than the interval between the light sources 1 are provided for each light source 1, and three shades of light from the light source 1 are irradiated to the shades through this. Therefore, when the optical member 2 is viewed from the light irradiation side, it appears that a plurality of light sources are arranged densely and irradiate light. For this reason, the number of actual light sources 1 is not increased, the distance between the light sources 1 and the shade 3 is increased, and the diffusivity of the shade 3 is not increased in order to improve the spatial luminance uniformity of the illumination light. However, spatial brightness uniformity can be improved. For this reason, according to the present embodiment, an illumination device with high luminance uniformity is provided without increasing the number of light sources 1, without increasing the thickness of the illumination device, and without increasing the diffusivity of the shade 3. can do. Generally, when the diffusivity of the shade 3 is lowered, the transmittance of the shade 3 can be increased, so that the luminous efficiency of the lighting device can be increased.

  Therefore, according to the present embodiment, it is possible to provide an illuminating device that can irradiate bright illumination light with high brightness uniformity while suppressing an increase in cost and reducing the thickness.

  In this embodiment, the ceiling light is described as an example of the lighting device, but it goes without saying that the present invention can be applied to other lighting devices. In the present embodiment, a plurality of optical elements 21 are provided for one light source 1, but the light source group is provided for a light source group having a plurality of light sources (for example, two to three light sources arranged close to each other). A plurality of optical elements 21 larger than the number of the light sources may be provided.

Next, a configuration example of the second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a cross-sectional view of a surface of the optical system according to the second embodiment that includes the center of the light source 1 and the center of the optical element 21 b and is orthogonal to the surface of the optical member 21. As shown in the figure, in the present embodiment, the centers of the exit surfaces 212 of the optical elements 21a and 21c are located outside the light source 1 with respect to the centers of the entrance surfaces 211 of the optical elements 21a and 21c. Before the description of the optical action of the example, referring to FIG. 6, the optical action when the center of the incident surface 211 of the optical element 21a and the center of the outgoing face 212 are coincident as in the first embodiment. explain. For simplicity, it is assumed that the incident surface 211 is sufficiently small and the distance from the light source 1 is sufficiently far from the size of the incident surface 211. Under this condition, the light beam incident on the incident surface 211 from the light source 1 becomes substantially parallel light. The parallel light incident on the optical element 21 from the incident surface 211 converges at one point on the focal point of the incident surface 211. In the example of FIG. 6, it is assumed that the focal point of the incident surface 211 substantially coincides with the output surface 212.

  At this time, the light beam incident on the incident surface 211 of the optical element 21 from the light source 1 is refracted by the incident surface 211 and converged in a range that fits on the output surface 212. However, this light beam includes light beams having various angles. It is out. For this reason, a light ray incident at an angle larger than the critical angle with respect to the normal line of the emission surface 212 cannot be totally reflected by the emission surface 212 and pass through the emission surface 212, and becomes return light as an incident surface. Head to 211. The generation of such return light becomes a factor that reduces the transmittance of the optical element 21 or the optical member 2.

  On the other hand, in the illumination device according to the present embodiment, as shown in FIG. 5, each of the optical elements 21 a to 21 c has an exit surface 212 that is convex toward the shade 3 side and an incident surface that is convex toward the light source 1 side. Although it has a biconvex lens shape having 211, the optical elements 21a and 21c located on the periphery of the optical element 21b located on the optical axis of the light source 1 (that is, outside the optical element 21b) The center is located outside the center of the incident surface 211 of the optical elements 21 a and 21 c with respect to the light source 1. That is, in the present embodiment, the center of the exit surface 212 and the center of the entrance surface 211 are shifted so that the center of the exit surface 212 of each of the optical elements 21a and 21c is positioned outside the center of the entrance surface 211. It has a configuration. With such a configuration, the light beam that has converged so as to pass through the incident surface 211 toward the focal point of the incident surface 211 can be incident on the exit surface 212 at a deep angle as illustrated. Become. For this reason, it is possible to suppress the return light that is totally reflected by the exit surface 212 and travels toward the entrance surface 211, and the passing rate of the optical member 2 can be increased.

  Further, in the configuration of the present embodiment, if the optical element 21 is configured so that the focal point of the emission surface 212 substantially coincides with the incident surface 211 as in the first embodiment, the incident surface as described in the first embodiment. Since the illuminance distribution on 211 is uniform, outgoing light having a uniform light distribution can be obtained from the outgoing surface 212. As a result, illumination is performed on the shade 3 so that the illuminance distribution is uniform.

  As described above, according to the configuration of this embodiment, since the incident light from the incident surface 211 is suppressed from being totally reflected by the output surface 212, the luminous efficiency is improved while improving the illuminance distribution on the shade 3. be able to.

  Next, a configuration example of the third embodiment of the present invention will be described with reference to FIG. FIG. 7 shows a cross-sectional view of the surface of the optical system and the optical member 2 according to the third embodiment that includes the center of the light source 1 and the center of the optical member 2 and is orthogonal to the surface of the optical member 2.

  As shown in FIG. 4, the illumination device according to the present embodiment forms a part of a Fresnel lens as an optical element 21 formed on the optical member 2 instead of a biconvex lens. More specifically, in this embodiment, as shown in FIG. 7, an incident surface Fresnel lens 214 having a convex surface directed toward the light source 1 is formed on the incident surface (light source 1 side) of the optical member 2. The exit surface Fresnel lens 215 is formed on the exit surface (side of the shade 4) with the convex toward the shade 4 side. The entrance surface Fresnel lens 214 and the exit surface Fresnel lens 215 are provided corresponding to each of the plurality of light sources 1. That is, a plurality of incident surface Fresnel lenses 214 and output surface Fresnel lenses 215 are provided in correspondence with each light source 1 on the surface of the optical member 2. Here, the focal length of the entrance-side Fresnel lens 214 and / or the exit-side Fresnel lens 215 is changed according to the position on the optical member 2.

  According to the configuration of the present embodiment, desired optical characteristics corresponding to the incident position on the optical member 2 can be realized in a wide area with respect to the light beam emitted from the light source 1 and incident on the optical member 2. . For example, the power of the incident-side Fresnel lens 214 and / or the emission-side Fresnel lens 215 lens is weak for the light beam emitted from the light source 1 in the direction close to the optical axis of the light source 1, and from the optical axis of the light source 1. For light rays traveling in the direction away from the light source, the power of the incident-side Fresnel lens 214 and / or the output-side Fresnel lens 215 can be increased. That is, according to the configuration of the present embodiment, the emitted light beam of the light source 1 can be effectively irradiated onto the shade 3, so that the light can be uniformly irradiated onto the shade 3 while improving the efficiency.

  You may comprise so that the focus of the incident side Fresnel lens 214 may be located in the light emission surface of the light source 1, for example so that it may show in figure. In this configuration, the light beam emitted from the light source 1 enters the incident-side Fresnel lens 214 and is refracted, and is refracted and emitted again by the output-side Fresnel lens 215. The light is emitted substantially parallel to one optical axis. Even if the shade 3 is moved in the optical axis direction of the light source 1 (the direction perpendicular to the optical element 2 or the light source substrate 2) if the light beam is emitted from the emission-side Fresnel lens 215 in a direction parallel to the optical axis of the light source 1. The illuminance distribution in the region on the shade 3 where the outgoing light from the outgoing-side Fresnel lens 215 is irradiated hardly changes.

  That is, if the focal point of the incident-side Fresnel lens 214 is configured to be positioned on the light emitting surface of the light source 1, the optical performance fluctuation caused by the attachment error of the shade 3 can be effectively utilized while effectively using the emitted light beam of the light source 1. It is possible to provide an illuminating device and an optical system that can be suppressed and have high manufacturability with reduced assembly tolerances.

  In FIG. 7, the Fresnel lens formed on the optical member 2 is shown as having a convex shape on both the light source 1 side and the shade 3 side, but one of them is a combination of either a flat surface or a concave surface shape. It may be a configuration.

  Next, a configuration example of the fourth embodiment of the present invention will be described with reference to FIGS. The fourth embodiment is an embodiment of a two-dimensional arrangement of optical elements in the optical member 2.

  FIG. 8 shows a first arrangement example of the optical elements in the optical member 2 according to the present embodiment, and shows a front view of the optical member 2 as viewed from the light irradiation side.

  As shown in FIG. 8, in the first arrangement example, an optical element 21 (for example, both of the first embodiment) is placed in a predetermined region on the optical member 2 with the position corresponding to each of the plurality of light sources 1 as the center. Convex lenses) are arranged radially with reference to positions corresponding to the respective light sources 1. That is, a plurality of predetermined regions in which a plurality of circular optical elements 21 are radially arranged with respect to a position corresponding to one light source 1 are provided on the optical member 2 corresponding to each light source 1. In this embodiment, the shape of the optical element 21 viewed from the light irradiation side is a circle.

  When the shade 3 is wide with respect to the region where the light source 1 can irradiate light, a plurality of light sources 1 are used to irradiate a wide area. However, if the configuration of this embodiment is used, as described in the first embodiment, etc. A wide area of the shade 4 can be irradiated. In the first arrangement example, a plurality of optical elements 21 corresponding to each of the plurality of light sources 1 are provided radially with respect to a position corresponding to one light source 1, so that the geometrical characteristics of the optical characteristics of the optical elements 21 are obtained. It is possible to maintain a general symmetry. In this example, the number of optical elements corresponding to each light source 1 is the same. For example, the number of optical elements corresponding to the light source 1 located at the center of the optical member 2 is set to the light source 1 located outside. The number may be larger than the number of optical elements corresponding to. When it is desired to improve the luminance uniformity around the illumination device irradiation surface, conversely, the number of optical elements corresponding to the light source 1 located outside the optical member 2 is set to the number of optical elements corresponding to the light source 1 located in the center. It may be more than the number.

  That is, with the configuration of the present embodiment, an optical system that uniformly irradiates the shade 3 by increasing the transmittance of the optical member 2 while using the plurality of light sources 1 can be provided.

  Next, a second arrangement example of optical elements according to the present embodiment will be described with reference to FIG. FIG. 9 shows a second arrangement example of the optical elements in the optical member 2 according to the present embodiment, and shows a front view of the optical member 2 as viewed from the light irradiation side.

  As shown in FIG. 9, the first arrangement example includes a plurality of areas around the positions corresponding to the light sources 1 in a predetermined area on the optical member 2 centered on the positions corresponding to the plurality of light sources 1. The optical elements 251 having a polygonal shape (hexagonal shape in FIG. 9) are arranged so as to be in contact with each other (so that no gap is generated between the optical elements 251). At this time, the group of optical elements 251 arranged in one predetermined region passes through the center of the optical element 251 corresponding to the position of the light source 1 (on the optical axis of the light source 1) and the center of the optical element 251 adjacent thereto. The optical members 2 are arranged symmetrically with respect to the planar straight line. That is, a plurality of predetermined regions arranged symmetrically with respect to a straight line with a plurality of hexagonal optical elements 21 corresponding to one light source 1 are provided on the optical member 2 corresponding to each light source 1. . It is assumed that the hexagonal optical element 21 has a biconvex lens shape as shown in FIG. 3 and the like, with a cross section passing through the center thereof and orthogonal to the surface of the optical member.

  According to the second arrangement example, since the plurality of polygonal optical elements 251 are arranged so as to be in contact with each other (so that no gap is generated between the optical elements 251), the surface area of the optical member 2 is increased. Of these, the region where the optical element 251 is present can be expanded. For this reason, the area | region where the optical element 21 functions in the optical member 2 can be increased. In this example, the number of optical elements corresponding to each light source 1 is the same. For example, the number of optical elements corresponding to the light source 1 located at the center of the optical member 2 is set to the light source 1 located outside. The number may be larger than the number of optical elements corresponding to. When it is desired to improve the luminance uniformity around the illumination device irradiation surface, conversely, the number of optical elements corresponding to the light source 1 located outside the optical member 2 is set to the number of optical elements corresponding to the light source 1 located in the center. It may be more than the number.

  That is, with the configuration of the second arrangement example, the amount of light that can be applied to the shade 3 among the light beams emitted from the plurality of light sources 1 can be increased, and the transmittance of the optical member 2 is increased so that the shade 3 can be used. It is possible to provide an optical system with an improved effect of uniform irradiation.

  Next, a third arrangement example of optical elements according to the present embodiment will be described with reference to FIG. FIG. 10 shows a third arrangement example of the optical elements in the optical member 2 according to the present embodiment, and shows a front view of the optical member 2 viewed from the light irradiation side.

  As shown in FIG. 10, the third arrangement example includes an area where the optical element 251 is arranged corresponding to a certain light source 1 and an area where an optical element is arranged corresponding to another light source 1. At least some of them cross or touch each other. Here, the optical element 251 has the same hexagonal shape as the optical element shown in FIG. That is, in this embodiment, a part of a plurality of optical elements 251 provided corresponding to a certain light source 1 and a part of a plurality of optical elements 251 provided corresponding to another light source 1 are mutually connected. Crossing or touching. Here, in the vicinity of the outer periphery of the irradiation surface, a part of a plurality of optical elements 251 provided corresponding to a certain light source 1 and a part of a plurality of optical elements 251 provided corresponding to another light source 1 Are crossing or contacting each other.

  As in the first or second arrangement example, the third arrangement example also has a configuration in which a plurality of optical elements 251 are arranged corresponding to one light source 1. In such a configuration, when a light beam from another light source 1 is incident on the optical element 251 corresponding to a certain light source 1 in a region where the plurality of light sources 1 are adjacent to each other, the light beam is different from the light beam incident from the certain light source 1. The light is emitted from the optical element 251 with characteristics. This causes a discontinuity of optical characteristics such as illuminance distribution at the boundary portion of the light source 1 on the shade 3.

  On the other hand, in the configuration of the third arrangement example, the optical element 251 is arranged on the outer peripheral side of the irradiation surface near the boundary between the plurality of light sources 1, and the optical element is disposed in the region 261 other than the outer peripheral side (inner side). In place of this, for example, a plurality of prisms or lenses are provided. Instead of this prism and lens, a surface having scattering characteristics may be provided. According to this configuration, it is possible to configure a state in which a plurality of light sources having different characteristics corresponding to the arrangement pitch of the optical elements 251 are arranged in a region near the boundary between the plurality of light sources 1 on the optical member 2. Therefore, according to the third arrangement example, it is possible to provide an optical system that suppresses an extreme change in optical characteristics even near the boundaries of the plurality of light sources 1 when the shade 3 is illuminated. Each of the plurality of prisms or lenses preferably has a smaller size than the optical element 251. However, it may be approximately the same size as the optical element 251 or may be slightly larger.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Optical member, 21,251 ... Optical element, 211 ... Incident surface, 212 ... Outgoing surface, 3 ... Shade, 4 ... Power supply part, 10 ... Light source substrate, 213 ... Incident side Fresnel lens, 214 ... Outgoing Side Fresnel lens

Claims (16)

In an illuminating device comprising a plurality of light sources and a shade as an outer case for diffusing and emitting light from the light source,
An optical member that is arranged between the plurality of light sources and the shade and that has a plurality of optical elements having a lens shape that refracts light from the light source and is two-dimensionally arranged;
An illuminating device configured to irradiate the shade with light emitted from the light source through the optical element.   The lighting device according to claim 1, wherein the light source is a white LED that emits white light.   2. The illumination device according to claim 1, wherein a plurality of the optical elements are provided corresponding to the plurality of light sources, and the number of the optical elements on the optical member is larger than the number of the light sources. A lighting device characterized by the above.   4. The illumination device according to claim 3, wherein the optical element is a biconvex positive lens including an incident surface having a convex surface toward the light source and an exit surface having a convex surface toward the shade side. A lighting device.   5. The illuminating device according to claim 4, wherein a focal point of the incident surface is located on the exit surface.   5. The illuminating device according to claim 4, wherein a focal point of the emission surface is located on the incident surface.   5. The illuminating device according to claim 4, wherein the center of the incident surface and the center of the exit surface substantially coincide with each other.   5. The illumination device according to claim 4, wherein a center of the emission surface of an optical element positioned around an optical element positioned on an optical axis of the one light source among the plurality of optical elements is the optical element. An illumination device, wherein the illumination device is located outside the center of the incident surface.   4. The illumination device according to claim 3, wherein the optical element is a Fresnel lens provided corresponding to each of the plurality of light sources and having a convex surface directed toward the light source side and the shade side. apparatus.   10. The illumination device according to claim 9, wherein the Fresnel lens includes an incident-side Fresnel lens provided on the light source side of the optical member and an emission-side Fresnel lens provided on the shade side of the optical member. The illumination apparatus is characterized in that a focal point of the incident-side Fresnel lens is located on a light emission surface of the light source corresponding to the incident-side Fresnel lens.   5. The illumination device according to claim 4, wherein the optical element has a circular shape when viewed from the light irradiation side.   5. The illumination device according to claim 4, wherein the optical element has a polygonal shape as viewed from the light irradiation side.   5. The illumination device according to claim 4, wherein the plurality of optical elements are arranged radially on the optical member with reference to a position corresponding to the one light source.   5. The illuminating device according to claim 4, wherein the plurality of optical elements provided corresponding to the respective light sources are in contact with each other.   5. The illumination device according to claim 4, wherein the plurality of optical elements provided corresponding to the respective light sources include, in the optical member, an optical element adjacent to the center of the optical element at a position corresponding to the one light source. The illumination device is arranged symmetrically with respect to a planar straight line of the optical member passing through the center of the optical member.   5. The lighting device according to claim 4, wherein a part of the plurality of optical elements provided corresponding to a certain light source and a part of the plurality of optical elements provided corresponding to a light source different from the certain light source. Are in contact with or crossing each other.

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