WO2022244350A1

WO2022244350A1 - Planar illumination device

Info

Publication number: WO2022244350A1
Application number: PCT/JP2022/006149
Authority: WO
Inventors: 祥吾鈴木; 銀河伊藤
Original assignee: ミネベアミツミ株式会社
Priority date: 2021-05-20
Filing date: 2022-02-16
Publication date: 2022-11-24

Abstract

A planar illumination device (1) according to an embodiment of the present invention comprises a substrate (2) on which a plurality of light sources (3) are arranged in a lattice shape in two dimensions, and a reflector (4) which has reflective surfaces (4a) that form openings (4b) corresponding to each of the plurality of light sources (3). The reflector (4) is disposed so that the openings (4b) are positioned closer to an emitting side than the top surfaces (3a) of the light sources (3), which are the surfaces on the opposite side to the surfaces on the substrate (2) side.

Description

Planar lighting device

The present invention relates to a planar lighting device.

A planar lighting device used as a backlight for a head-up display (HUD) or the like is required to have a brightness that is about 100 times higher than a display such as a cluster or CID (Center Information Display) where the user directly sees the display screen. be.

For example, the direct type backlight for HUD disclosed in Patent Document 1 is a surface light source in which a plurality of LEDs (Light Emitting Diodes) are arranged two-dimensionally in order to realize a high-brightness planar illumination device. It comprises light condensing means for converting the light from the light into substantially parallel light. The condensing means of Patent Document 1 is provided with Fresnel lenses at positions corresponding to the plurality of LEDs.

In addition, the direct type backlight disclosed in Patent Document 2 and Patent Document 3 includes a reflector formed with a reflective surface surrounding each of the plurality of LEDs in order to improve the output efficiency.

Patent Documents

2 and 3 also disclose a configuration in which a reflector is arranged away from a substrate on which the LED is arranged in order to improve ventilation and improve the heat dissipation effect of the LED. For example, in Patent Document 3, the reflector is separated from the substrate until the bottom surface of the reflector is at the same height as the light emitting surface of the LED.

JP 2007-87792 A JP-A-61-181002 JP-A-2004-185972

However, the direct type backlight for HUD has a small effective area, so if multiple LEDs are arranged for local dimming (partial lighting), the pitch between the LEDs becomes narrow. In such a case, in the conventional configuration, the reflector and the LED may interfere with each other when they expand and contract.

Also, when the reflector is created by injection molding, if the distance between the LEDs is narrow, the wall thickness of the reflector cannot be increased. For this reason, it is difficult to increase the height of the reflector wall from the viewpoint of the moldability of injection molding, and the luminous flux emitted from the LED is efficiently incident on the condensing lens arranged at the position corresponding to the LED. may not be possible. In such a case, there is a concern that the contrast may be lowered during local dimming, or that an unintended portion may be illuminated.

The present invention has been made in view of the above, and an object of the present invention is to provide a planar lighting device capable of realizing high-luminance, high-contrast local dimming.

In order to solve the above-described problems and achieve the object, a planar lighting device according to one aspect of the present invention provides a substrate on which a plurality of light sources are arranged two-dimensionally in a grid pattern, and a substrate corresponding to each of the plurality of light sources. a reflector having a reflective surface defining an aperture for the light source; The reflector is arranged such that the opening is located on the emission side of the opposite surface of the light source, which is the surface opposite to the substrate-side surface.

A planar lighting device according to one embodiment of the present invention can achieve local dimming with high luminance and high contrast.

FIG. 1 is a diagram showing a configuration example of a head-up display system. FIG. 2 is a front view of the planar lighting device according to the embodiment. FIG. 3 is a cross-sectional view of the planar illumination device taken along the line AA in FIG. 4 is a front view of the reflector shown in FIG. 3. FIG. FIG. 5 is a schematic diagram of grooves provided on both sides of a condenser lens. FIG. 6 is a diagram showing an example of the cross-sectional configuration of the incident side of the condenser lens. FIG. 7 is a diagram showing how light rays are refracted in the horizontal direction by a condenser lens. FIG. 8 is a diagram showing how light rays are refracted in the vertical direction by a condenser lens. FIG. 9 is a diagram showing an example of the cross-sectional configuration of the incident side of the field lens. FIG. 10 is a diagram showing how a field lens refracts light rays in the horizontal direction. FIG. 11 is an enlarged view showing dots provided on the other surface of the field lens. FIG. 12 is a diagram showing an example of the configuration of the exit-side surface of the field lens. FIG. 13 is a diagram for explaining a reflector of a comparative example; FIG. 14 is a diagram showing light beams incident on a condenser lens in a reflector arrangement of a comparative example. FIG. 15 is a diagram for explaining the size of the opening of the reflector that is possible in the embodiment. FIG. 16 is a diagram showing the result of luminance measurement. FIG. 17 is a diagram showing the result of luminance measurement. FIG. 18 shows the results of photometry.

A planar illumination device according to an embodiment will be described below with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, the dimensional relationship of each element in the drawings, the ratio of each element, and the like may differ from reality. Even between the drawings, there are cases where portions with different dimensional relationships and ratios are included. In principle, the contents described in one embodiment and modification are similarly applied to other embodiments and modifications.

(System configuration)
FIG. 1 is a diagram showing a configuration example of a head-up display system 100. As shown in FIG. In FIG. 1, in the case of a head-up display system 100 mounted on an automobile, the traveling direction of the automobile is the left direction (positive direction of the Y-axis) in the figure.

In FIG. 1, light emitted from the planar lighting device 1 passes through the liquid crystal panel 101 (L1), is reflected by the mirror 102 (L2), and is guided to the concave mirror 103. The light (L3) reflected from the concave mirror 103 is projected onto a screen 104 such as a windshield of an automobile, and the reflected light (L4) enters the driver's eye box (viewpoint) EB and is drawn on the liquid crystal panel 101. The image is recognized as a virtual image. It should be noted that "H (horizontal direction)" in the X-axis direction and "V (vertical direction)" in the Y-axis direction are both horizontal and vertical directions of the virtual image viewed from the eyebox EB, as will be described later. This is to show the correspondence between the direction and the direction of the output surface of the planar illumination device 1 .

(embodiment)
FIG. 2 is a front view of the planar lighting device 1 according to the embodiment. For convenience, the light-emitting surface of the planar illumination device 1 is in the XY plane, and the thickness direction of the planar illumination device 1 is the Z direction. In addition, in a usage state where the lighting for a head-up display is reflected by a screen or the like and visible to the user, the X-axis direction corresponds to the horizontal direction (H), and the Y-axis direction corresponds to the vertical direction (V). In addition, hereinafter, the horizontal direction in the state of use that is reflected by the screen, etc. and visible to the user is simply referred to as the "horizontal direction", and the vertical direction in the state of use that is reflected by the screen, etc., and is visible to the user is simply referred to as the "vertical direction." ” may be stated.

In FIG. 2, the planar illumination device 1 has a substantially rectangular plate-like outer shape, and light is emitted from the inside of the opening 7a of the frame 7. As shown in FIG. The size of the opening 7a is, for example, 42 mm in the X-axis direction and 21 mm in the Y-axis direction. It should be noted that the outer shape of the planar illumination device 1 is not limited to that illustrated. Also, the frame 7 may be omitted.

FIG. 3 is a cross-sectional view of the planar lighting device 1 taken along line AA in FIG. Note that the frame 7 is omitted in FIG. In FIG. 3, a plurality of light sources 3 such as LEDs (Light Emitting Diodes) are arranged two-dimensionally in a grid pattern on a substrate 2 made of aluminum or the like, which has excellent heat dissipation properties. are placed in The individual light sources 3 are individually driven and can cope with so-called local dimming.

A reflector 4 is arranged on the output side of the substrate 2 where the light source 3 is arranged. 4 is a front view of the reflector 4 shown in FIG. 3. FIG. The reflector 4 is formed with a plurality of openings 4b in a grid pattern so as to correspond to the plurality of light sources 3 arranged in a grid pattern. The reflector 4 has a reflecting surface 4a forming openings 4b corresponding to the plurality of light sources 3 respectively. In one example shown in FIGS. 3 and 4, the reflector 4 has four reflective surfaces 4a surrounding an opening 4b. Although the reflector 4 has an opening on the emission side and an opening on the substrate 2 side, the opening 4b is the opening on the substrate 2 side.

The reflector 4 has a wall portion 4c formed so that openings 4b corresponding to the plurality of light sources 3 are arranged in a lattice. The wall portion 4c has a shape in which a plurality of substantially triangular prism-shaped wall portions extending in the X-axis direction and a plurality of substantially triangular prism-shaped wall portions extending in the Y-axis direction are assembled in a grid pattern. The reflecting surface 4a is a wall surface of the wall portion 4c, and the two reflecting surfaces 4a facing each other in the X-axis direction are inclined so as to separate from each other in the Z-axis positive direction (exit side) from the opening 4b side. The two reflective surfaces 4a facing each other in direction are slanted away from each other in the positive direction of the Z-axis from the opening 4b side. The reflector 4 is made of, for example, white resin or the like in order to enhance the effect of reflection. The reflector 4 of the embodiment is an injection-molded product.

The reflector 4 of the embodiment is arranged so that the opening 4b is located on the emission side of the light emitting surface of the light source 3, as shown in FIG. The light emitting surface of the light source 3 corresponds to the upper surface 3a of the light source 3 shown in FIG. In other words, the reflector 4 is arranged so that the opening 4b is located on the emission side of the upper surface 3a of the light source 3. As shown in FIG. The upper surface 3a of the light source 3 is the opposite surface opposite to the surface of the light source 3 on the substrate 2 side. Further, the bottom surface 4d of the wall portion 4c of the reflector 4 is arranged in a state of floating from the substrate 2 so as to be higher than the light source 3, as shown in FIG. For this arrangement, a frame portion 4e that is thicker than the wall portion 4c is formed on the periphery of the reflector 4. As shown in FIG. The wall portion 4c is supported by the frame portion 4e at a position between the upper end and the lower end of the frame portion 4e, and spaces are provided above and below the wall portion 4c.

A flange portion 4f that protrudes outward is formed from the lower end portion of the frame portion 4e. The flange portion 4f is formed in order to secure a sufficient contact surface with the substrate 2. As shown in FIG. It should be noted that only the lower surface of the frame portion 4e may be used as the ground surface with the substrate 2 without providing the flange portion 4f. The effect of the configuration in which the opening 4b of the reflector 4 is located on the emission side of the upper surface 3a of the light source 3 will be described later.

A condenser lens 5 is arranged on the output side of the reflector 4 . The condenser lens 5 is provided with a condensing lens at a position corresponding to each of the plurality of light sources 3 . For example, the incident side surface 5a of the condenser lens 5 is formed with a first linear Fresnel lens in which grooves forming the uneven surface of the lens extend in one direction. A second linear Fresnel lens is formed on the output-side surface 5b of the condenser lens 5 so that the grooves constituting the concave-convex surface of the lens extend in a direction orthogonal to one direction of the surface 5a. For example, a first linear Fresnel lens having grooves extending in the depth direction (Y-axis direction) of FIG. 3 is formed on the lower surface 5a of the condenser lens 5 in FIG. A second linear Fresnel lens having grooves extending in the left-right direction (X-axis direction) in FIG. 3 is formed on the surface 5b. In the example shown in FIG. 3 , the condenser lens 5 is installed on the upper end surface of the frame portion 4 e of the reflector 4 .

A field lens 6 that changes the light distribution and diffuses the light is arranged on the output side of the condenser lens 5 . The field lens 6 shown in FIG. 3 is, for example, a lens for changing the light distribution in the horizontal direction. A prism is formed from which the groove extends. On the upper surface 6b of the field lens 6 in FIG. 3, minute dots for diffusing light are formed over the entire surface. A gap is provided between the condenser lens 5 and the field lens 6 . Such a gap is formed by making the peripheral edge of one of the condenser lens 5 or the field lens 6 thick and frame-shaped, or by providing a frame-shaped spacer between the condenser lens 5 and the field lens 6 .

FIG. 5 is a schematic diagram of

grooves

5c and 5d provided on both surfaces of the condenser lens 5. FIG. A groove 5c extending in the Y-axis direction and constituting a first linear Fresnel lens is formed in a surface 5a on the lower side (incident side) of the condenser lens 5. As shown in FIG. An upper (outgoing side) surface 5b of the condenser lens 5 is formed with a groove 5d extending in the X-axis direction and constituting a second linear Fresnel lens. FIG. 6 is a diagram showing an example of the cross-sectional configuration of the incident side of the condenser lens 5. As shown in FIG. The entrance-side surface 5a of the condenser lens 5 has a prism structure in which a cylindrical convex lens is a Fresnel lens for each segment corresponding to the light source 3 (FIG. 3). ). The angle of the prism is reversed at the segment boundary BL between adjacent segments. The segment boundary BL shown in FIG. 6 is positioned directly above the ridgeline of the wall portion 4c extending in the Y-axis direction in FIG. Also, on the output side of the condenser lens 5, a similar prism structure is provided, although the extending directions of the grooves are perpendicular to each other. In the prism structure on the output side of the condenser lens 5, the segment boundary between adjacent segments is positioned directly above the ridgeline of the wall portion 4c extending in the X-axis direction in FIG.

The first and second linear Fresnel lenses have a pitch of the light source 3 (FIG. 3) arranged directly below (the first linear Fresnel lens has a pitch in the X-axis direction, and the second linear Fresnel lens has a pitch in the Y-axis direction). ) are formed periodically. During assembly, the condenser lens 5 is arranged so that the center of the lens is positioned right above the light source 3 in each of the Y-axis direction and the X-axis direction. Although it is difficult to form annular Fresnel lenses corresponding to the number of light sources 3 according to the position of each light source 3, linear linear Fresnel lenses can be formed in units of columns or rows according to the plurality of light sources arranged linearly. is relatively easy to form. By forming the linear Fresnel lenses perpendicular to both surfaces of the transparent substrate, the intersection point between the center of one linear Fresnel lens and the center of the other linear Fresnel lens corresponds to the center of the light source. Acts as a Fresnel lens.

FIG. 7 is a diagram showing how light rays in the horizontal direction are refracted by the condenser lens 5. FIG. That is, FIG. 7 shows the behavior of light in a cross section along the horizontal direction (X, H) and the normal direction (Z) of the exit surface during use. Illustration of the field lens 6 is omitted. In FIG. 7, the light emitted from the light source 3 and indicated by the dashed line is emitted by the first linear Fresnel lens, which has an uneven surface formed by grooves extending in the Y-axis direction provided on the lower surface 5a of the condenser lens 5, to form an X-ray. The light is refracted in the -Z plane and becomes substantially parallel light. Although the light is parallel light along the normal direction of the emission surface, it may be parallel light with a predetermined inclination with respect to the normal direction of the emission surface. The second linear Fresnel lens, which has an uneven surface formed by grooves extending in the X-axis direction provided on the upper surface 5b of the condenser lens 5, does not act in the horizontal direction. emitted.

FIG. 8 is a diagram showing how light rays in the vertical direction are refracted by the condenser lens 5. FIG. That is, FIG. 8 shows the behavior of light in a cross section along the vertical direction (Y, V) and the normal direction (Z) to the exit surface during use. Illustration of the field lens 6 is omitted. In FIG. 8, the light emitted from the light source 3 indicated by the dashed line is not strongly refracted by the first linear Fresnel lens provided on the lower surface 5a of the condenser lens 5, and enters the condenser lens 5 as it is. move on. Then, the light is refracted in the YZ plane by a second linear Fresnel lens having an uneven surface formed from grooves extending in the X-axis direction provided on the upper surface 5b of the condenser lens 5, and emitted as substantially parallel light. be done. Although the light is parallel light along the normal direction of the emission surface, it may be parallel light with a predetermined inclination with respect to the normal direction of the emission surface.

Next, FIG. 9 is a diagram showing an example of the cross-sectional configuration of the incident side of the field lens 6. As shown in FIG. In FIG. 9, one cross section of the incident side surface 6a of the field lens 6 has a prism structure equivalent to a Fresnel lens instead of a ring-shaped concave lens. Y-axis direction). The tilt angle of the prism becomes steeper as it moves away from the center.

FIG. 10 is a diagram showing how light rays are refracted in the horizontal direction by the field lens 6. FIG. That is, FIG. 10 shows the behavior of light in a cross section along the horizontal direction (X, H) and the normal direction (Z) of the exit surface during use. In a head-up display or the like as shown in FIG. 1, light from a planar illumination device 1 as a backlight for a liquid crystal panel 101 is reflected on a screen 104 via a mirror 102 or a concave mirror 103 and used. catch someone's eye. Since the optical axis of the light reflected by the concave mirror 103 is tilted inward, in order to secure the angle range of the optical axis required for the light emitted from the concave mirror 103, the optical axis outside the center must be tilted outward. It is necessary to supply light from the planar illumination device 1 which is inclined at . Note that the optical axis is the axis along the direction of the highest intensity of light emitted from one light source or minute portion (regardless of whether it is parallel light or radiated light). Therefore, the optical axis is inclined outward in the horizontal direction according to the horizontal distance from the center of the planar lighting device 1 . As a result, it is possible to secure the angle range of the optical axis required for the light emitted from the concave mirror 103, and to prevent the end of the virtual image from disappearing.

In the vertical direction as well, it is necessary to tilt the outer optical axis outward according to the curvature of the concave mirror 103. Generally, however, the tilt of the optical axis in the vertical direction with respect to the horizontal direction can be small. , the light is assumed to be approximately parallel light. If the vertical optical axis also needs to be tilted, then the vertical optical axis is also tilted. As for the inclination of the optical axis, the center may be inclined in a predetermined direction instead of the substantially parallel light, and both sides thereof may be inclined outward with respect to the inclination of the center.

The lower side of FIG. 10 shows the cross-sectional configuration of the planar illumination device 1, similar to FIG. The angle is changed to 2°, and the angle next to it is changed to 4°. The numerical values of the tilt angles shown in the figure are only examples. Note that the inclination angle is determined by the shape of the prism that constitutes the field lens 6 .

In FIG. 10, in the region R1 near the center, the inclination angle is 0°, and light is emitted in the front direction (normal direction) of the field lens 6 as shown in the enlarged view on the upper side of the figure. In the area R2 located on the left side of the center, the angle of inclination is 6°, and as shown in the enlarged view on the upper side of the drawing, light is emitted that is inclined to the left with respect to the front direction of the field lens 6. In the region R3 located on the right side of the center, the angle of inclination is 6°, and as shown in the enlarged view on the upper side of the figure, light is emitted that is inclined to the right with respect to the front direction of the field lens 6. In addition, although the inclination angle is changed for each light source 3 in FIG. 10, the inclination angle may be changed for each area including a plurality of light sources 3 .

Next, FIG. 11 is an enlarged view (enlarged view of region R in FIG. 11) for showing dots 6c provided on the other surface 6b of the field lens 6. As shown in FIG. FIG. 12 is a diagram showing an example of the configuration of the surface of the field lens 6 on the output side. 11 and 12, minute dots 6c are formed on the upper surface 6b of the field lens 6 in the figures, which are formed from a mold or the like formed by laser processing or the like. The minute dots 6c diffuse the light passing therethrough to improve brightness uniformity. In place of the dots provided on the other surface 6b of the field lens 6, a general diffusion sheet separate from the field lens 6 may be used.

The planar illumination device 1 having the above configuration is used as a backlight for a head-up display. As a result, the planar illumination device 1 can perform local dimming with high brightness and high contrast. This point will be described below.

FIG. 13 is a diagram for explaining a reflector of a comparative example. 13, the opening 4b of the reflector 4 shown in FIG. In FIGS. 4 and 13, the light sources 3 are arranged at narrow intervals for local dimming (partial lighting). For example, in the reflector 4 shown in FIG. 4, 220 openings 4b are provided in 10 rows and 22 columns, and 220 light sources 3 can be arranged. It is arranged in an effective area (the size of the opening 7a) whose axial direction is 21 mm. From this, it can be seen that the pitch of the light sources 3 is very narrow.

Therefore, in the comparative example shown in FIG. 13, the bottom surface 4d of the reflector 4 and the light source 3 (LED package) are in close proximity, and when the reflector 4 and the light source 3 expand and contract, they may interfere with each other. There is In contrast, in the arrangement of the embodiment shown in FIG. 4, the opening 4b of the reflector 4 is arranged at a position higher than the upper surface 3a of the light source 3, so even if the reflector 4 and the light source 3 expand and contract, the reflector There is no possibility that the wall portion 4c of 4 and the light source 3 will come into contact with each other.

FIG. 14 is a diagram showing light beams incident on the condenser lens 5 in the reflector arrangement of the comparative example. In the comparative example shown in FIGS. 13 and 14 and the embodiment shown in FIG. 3, the shape of the wall portion 4c is the same. Since the space between the light sources 3 is narrow, the bottom surface 4d of the reflector 4 cannot be increased, and it is difficult to increase the height of the wall portion 4c of the reflector 4 from the viewpoint of moldability of injection molding. Therefore, the height of the wall portion 4c is lowered, and the luminous flux incident on the condenser lens 5 on the same segment is as low as 20% to 25% of the total luminous flux emitted from the light source 3, as shown in FIG. .

In addition, light beams that have crossed the segment boundary and entered the condenser lens 5 of a segment other than the corresponding segment are condensed at a wide angle (for example, 40° to 50°). For this reason, there is a concern that the contrast will be lowered during local dimming and that an unintended portion will be lit. It is conceivable to bring the condenser lens 5 closer to the reflector 4 to increase the efficiency of incidence on the condenser lens 5. likely to.

On the other hand, like the reflector 4 of the embodiment shown in FIG. It is possible to increase the ratio of the light flux incident on the condenser lens 5 of the segment corresponding to the light source 3 out of the total light flux. For this reason, in the embodiment, the effectively usable luminous flux is increased, and an improvement in luminance can be expected.

Also, in the embodiment shown in FIG. 3, the opening 4b of the reflector 4 is smaller than the outer periphery of the upper surface 3a of the light source 3 when viewed from above. However, in the embodiment, as shown in FIG. 15, if the opening 4b of the reflector 4 is larger than the outer periphery of the light emitting surface 3b of the light source 3 in top view, it is made smaller than the outer periphery of the upper surface 3a of the light source 3. be able to. FIG. 15 is a diagram for explaining the size of the opening 4b of the reflector 4 that is possible in the embodiment. That is, in the comparative example, the opening 4b of the reflector 4 had to be made larger than the circumference of the upper surface 3a of the light source 3, whereas in the embodiment, the opening 4b can be made smaller. In other words, in the embodiment, the bottom surface 4d can be enlarged, and as a result, the walls 4c of the reflector 4, which are made by injection molding, can be raised. For this reason, in the embodiment, it is assumed that effects such as high contrast and elimination of unnecessary light distribution can be obtained.

16 and 17 are diagrams showing the results of luminance measurement. In FIG. 16, a device in which the reflectors 4 are arranged in the arrangement of the comparative example and the reflectors 4 are arranged in the arrangement of the embodiment in the surface light source in which the light sources 3 are arranged in 216 positions other than the four corners out of 220 positions in 10 rows and 22 columns. It shows the results of comparison with the device with As shown in FIG. 16, the all-lamp lighting luminance distribution under the same all-lamp lighting conditions (45 mA×2.6 V×216 pcs=27.2 W) is substantially the same between the comparative example and the embodiment. The center luminance (diameter 6 mm) of the lamp lighting luminance distribution is also substantially the same between the comparative example and the embodiment.

On the other hand, in the one-lamp lighting luminance distribution shown in FIG. ² , the embodiment had an increase of about 3.3% to 734.410 cd/m ² . FIG. 17 is a cross-sectional profile when one lamp is lit. FIG. 17 shows profiles of relative luminance normalized by setting the maximum luminance of the comparative example and the maximum luminance of the embodiment to "1,000,000 cd/m ² ". It can be seen from FIG. 17 that the contrast is improved in the embodiment than in the comparative example.

FIG. 18 is a diagram showing the results of photometric measurements. FIG. 18 shows the luminous intensity distribution from the light source 3 to the reflector 4 and the profile (vertical direction: 0°, horizontal direction: -90° to +90°) for each of the comparative example and the embodiment. From the results of FIG. 18, it is suggested that in the embodiment, the light is distributed in the front direction more than in the comparative example, and unnecessary light distribution is reduced. From such results shown in FIGS. 16 to 18, it can be seen that the planar illumination device 1 according to the embodiment can realize local dimming with high brightness and high contrast.

Note that in the embodiment, instead of the condenser lens 5, a condenser lens formed with the first linear Fresnel lens and a condenser lens formed with the second linear Fresnel lens may be used. Also, the embodiment may use a concentric Fresnel lens instead of the condenser lens 5 . Further, in the embodiment, a lens having an arbitrary configuration can be used as the field lens 6 as long as the required light distribution characteristics can be realized.

Also, in the above embodiment, the light source 3 that emits light from the upper surface 3a has been described. However, in the configuration in which the opening 4b of the reflector 4 is located on the emission side of the upper surface 3a of the light source 3, even if the light source 3 emits light from the upper surface 3a and the side surface, the light source 3 emits light only from the side surface. Even a light source is applicable.

Also, the present invention is not limited by the above embodiments. The present invention also includes those configured by appropriately combining the respective constituent elements described above. Further effects and modifications can be easily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the above-described embodiments, and various modifications are possible.

1 Planar illumination device, 2 substrate, 3 light source, 3a upper surface (opposite surface of light source 3 opposite substrate 2 side), 4 reflector, 4a reflective surface, 4b opening, 4c wall, 4d Bottom, 4e Frame, 4f Flange, 5 Condenser lens, 6 Field lens, 7 Frame

Claims

a substrate on which a plurality of light sources are arranged two-dimensionally in a grid pattern;
a reflector having a reflective surface forming openings corresponding to each of the plurality of light sources;
with
The planar illumination device, wherein the reflector is arranged such that the opening is located on the emission side of the opposite surface of the light source, which is the surface opposite to the substrate-side surface.
The reflector has a wall portion formed so that the wall surface serves as the reflective surface, and the openings corresponding to the plurality of light sources are arranged in a grid pattern,
2. The planar illumination device according to claim 1, wherein the bottom surface of said wall portion is arranged so as to be positioned closer to the emission side than said opposite surface of said light source.
The reflector has a frame on its periphery that is thicker than the height of the wall,
3. The planar lighting device according to claim 2, wherein said wall portion is supported by said frame portion at a position between an upper end and a lower end of said frame portion.
The planar lighting device according to any one of claims 1 to 3, wherein the reflector is an injection-molded product.
The planar lighting device according to any one of claims 1 to 4, wherein the opening is larger than the light emitting surface of the light source and smaller than the circumference of the opposite surface of the light source when viewed from above.
a condenser lens disposed on the output side of the reflector and provided with condensing lenses at positions corresponding to each of the plurality of light sources;
The planar illumination device according to any one of claims 1 to 5, comprising
The planar illumination device according to any one of claims 1 to 6, wherein each of the plurality of light sources is individually driven so as to be compatible with local dimming.