JP2020119683A - Luminaire and light diffusion member - Google Patents

Abstract

To provide a luminaire and a light diffusion member capable of suppressing generation of luminance spots.SOLUTION: A luminaire 1 includes: a substrate 11; light emitting elements 12; and a light diffusion member 50 formed in a hollow conical shape from a tabular base material having light transmissivity, disposed on the substrate 11 so as to cover the light emitting elements 12 on the surface where the light emitting elements 12 are mounted in the substrate 11, and for diffusing the light radiated from the light emitting elements 12. The light diffusion member 50 includes: a main part 500 which is a hollow triangular pyramid shape in which a hole is formed at its apex; and an extension part 524 which is provided integrally continuous to the main part 500, which extends in the direction toward the apex TP1 along an outside surface of the main part 500, and in which at least part is oppositely arranged to the hole formed at the apex TP1 of the main part 500.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lighting device and a light diffusion member.

Illumination including a light source having a light emitting element such as an LED (Light Emitting Diode), an instrument body having a socket to which the light source is connected, a globe attached to the instrument body so as to include the light source, and a diffuse transmission body A device has been proposed (see, for example, Patent Document 1). Here, the diffusive transmissive body is tubular and is arranged between the light source in the region inside the globe and the inner wall of the globe, and diffuses the light emitted from the light source and transmits it to the inner wall side of the globe. This luminaire is provided with this diffuse transmission body, so that the luminance unevenness on the irradiation target surface of the luminaire when the light source is turned on is reduced.

JP, 2011-108587, A

However, in the luminaire described in Patent Document 1, for example, when a component such as a terminal block is disposed on the side of the light source, the shadow of this component is caused by the light emitted from the light source in the direction toward the component. Since the light is projected to the side, there is a risk that the luminance unevenness in the entire irradiation target area of the lighting fixture becomes large when the light source is turned on.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an illumination device and a light diffusing member that can suppress the occurrence of luminance unevenness.

In order to achieve the above object, the lighting device according to the present invention,
Board,
At least one light emitting device mounted on the substrate;
It is formed from a translucent plate-shaped base material in a hollow weight shape and is arranged on the substrate so as to cover the at least one light emitting element on the surface side of the substrate on which the at least one light emitting element is mounted. And a light diffusing member for diffusing light emitted from the at least one light emitting element.

According to the present invention, the light diffusing member is formed of a light-transmissive plate-shaped base material in the shape of a hollow cone, and has at least one light-emitting element on the surface side of the substrate on which the at least one light-emitting element is mounted. It is arranged on the substrate so as to cover it. Thereby, the light emitted from at least one light emitting element is diffused by the light diffusing member in all directions including the direction toward the top of the light diffusing member. Therefore, for example, when a component such as a terminal block is arranged laterally of at least one light emitting element on the substrate, the light causing the shadow of this component is also directed to the top of the light diffusing member by the light diffusing member. The shadow is weakened by being diffused into the shadow and irradiating the shadow with the diffused light. Therefore, there is an advantage that the occurrence of luminance unevenness in the entire irradiation target area of the lighting device is suppressed when the lighting device is turned on.

It is a disassembled perspective view of the illuminating device which concerns on embodiment of this invention. (A) is a cross-sectional view of the illumination device according to the embodiment, and (B) is a cross-sectional arrow view taken along the line AA of (A). It is a perspective view of the light diffusion member which concerns on embodiment. It is a top view of the base material used as the base of the light diffusing member which concerns on embodiment. It is a schematic diagram for explaining the light distribution characteristic of the lighting installation concerning a comparative example. It is a schematic diagram for explaining the light distribution characteristic of the lighting installation concerning an embodiment. It is a perspective view of the light diffusion member which concerns on a modification.

Hereinafter, a lighting device according to an embodiment of the present invention will be described with reference to the drawings. The lighting device according to the present embodiment is used by being attached to a ceiling or a wall of a building, and by disposing a light diffusing member inside the cover, it is possible to suppress the occurrence of luminance unevenness. is there.

As shown in FIG. 1, the lighting device 1 includes a light source unit 10, a base member 20, a cover 30, a back cover 40, and a light diffusing member 50. In addition, the lighting device 1 has, for example, an AC-DC converter and a DC-DC converter, and converts the alternating current supplied from the alternating current power source into direct current, steps down the voltage, and outputs the lighting circuit unit to the light source unit 10. Also provided (not shown). The lighting device 1 is used, for example, in a state where the base member 20 is attached to the building material. The light source unit 10 includes a substrate 11, three light emitting elements 12 mounted on the substrate 11, and a terminal block 13 arranged on the substrate 11. The board 11 is, for example, a rectangular plate-shaped printed wiring board on which a conductor pattern is formed. Through holes 11 a penetrating in the thickness direction of the substrate 11 are formed at two locations in the region of the substrate 11 where the light diffusion member 50 is arranged. Further, as shown in FIG. 2A, notches 11b having a rectangular shape in plan view for fixing the substrate 11 to the base member 20 are formed at both ends in the lateral direction of the substrate 11. The light emitting element 12 is, for example, an LED (Light Emitting Diode) element. The three light emitting elements 12 are arranged at three vertices of a virtual equilateral triangle when the substrate 11 is viewed in plan. A power supply line derived from the lighting circuit unit is connected to the terminal block 13.

Returning to FIG. 1, the base member 20 is made of resin and is interposed between the main body portion 21, the frame portion 22 located on the outer peripheral portion of the main body portion 21, and the main body portion 21 and the main body portion 22, The connecting portion 23 connects the frame 21 and the frame portion 22. The frame portion 22 has a cylindrical tubular portion 22a, an annular portion 22b that is annular and continuous to the tubular portion 22a at the inner peripheral edge, and a cylindrical shape that is cylindrical and continuous at the outer peripheral edge of the annular portion 22b. And a portion 22c. In addition, a protruding portion 221 that protrudes in a direction orthogonal to the cylinder axis direction of the cylindrical portion 22a and has a through hole 221a penetrating the bottom wall 221b on the +Z direction side is disposed in a part of the cylindrical portion 22a. There is. The shaft portion of the screw 234 is inserted into the through hole 221a. Then, the screw 234 is arranged in a state where its head is in contact with the outer peripheral portion of the through hole 221a on the +Z direction side of the bottom wall 221b. Further, a washer 233, a ring 232, and a lock piece 231 for bundling the power supply wires are inserted through the shaft portion of the screw 234. The nut 235 is screwed onto the shaft portion of the screw 234 with the washer 233, the ring 232 and the lock piece 231 being inserted through the shaft portion of the screw 234. The ring 232 is formed of an elastic member such as an elastomer. Therefore, by tightening the nut 235 to the screw 234, the lock piece 231 is firmly sandwiched between the washer 233 and the nut 235 by the restoring force of the ring 232, and the rotation of the lock piece 231 is restricted.

The main body 21 has a cylindrical side wall 21b and a bottom wall 21a provided inside the side wall 21b. An engagement protrusion 212 for engaging the cover 30 with the base member 20 is provided on the outer wall of the side wall 21b so as to extend along the circumferential direction of the side wall 21b. Further, an engagement hole 215 is formed in the side wall 21b at a position adjacent to the base end side of the engagement protrusion 212 on the −Z direction side. As shown in FIG. 2B, the bottom wall 21a has a first flat portion 211a, a second flat portion 213a, and a curved portion 212a. The first flat portion 211a is located on the +Z direction side inside the side wall 21b, and a rib 211b that projects in the +Z direction at the end on the +Y direction side and that supports the substrate 11 of the light source unit 10 at the tip is provided. In addition, as shown in FIG. 1, three ribs 211b are provided, and the +Y direction side at the tip of each of the three ribs 211b is connected to the elongated beam 211c. Further, a positioning piece 211d for positioning the substrate 11 is interposed between both ends of the beam 211c and the inside of the side wall 21b. Further, an opening 214a is formed between the side edge of the first flat portion 211a on the +Y direction side and the side wall 21b to route the power line derived from the lighting circuit unit to the terminal block 13 of the light source unit 10. ing. The second flat portion 213a is located inside the side wall 21b, and is continuous with the side wall 21b at the end of the side wall 21b on the −Z direction side. The curved portion 212a is continuous with the −Y direction side end of the first flat portion 211a and the +Y direction side end of the second flat portion 213a, and is curved so as to be convex in the −Z direction side. .. Further, on the +Z direction side of the curved portion 212a, there is provided a rib 211e protruding in the +Z direction and supporting the substrate 11 at the tip. In addition, an engaging claw 213 that engages with the notch 11b of the substrate 11 is provided at the tip of the rib 211e. Then, the substrate 11 is placed on the tips of the ribs 211b and 211e, and as shown in FIG. 2A, the positioning piece 211d abuts on the end portion on the +Y direction side, and the notch in the substrate 11 is formed. It is fixed to the base member 20 with the engaging claws 213 engaged with the outer peripheral portion of 11b.

Returning to FIG. 1, the cover 30 is made of a translucent resin and has a hollow hemispherical shape. As shown in FIG. 2B, the inner wall of the cover 30 extends radially from the apex of the cover 30 toward the peripheral edge and scatters light incident from the light source unit 10 via the light diffusing member 50. The ridge portion 311 is formed. As shown in FIG. 1, engagement claws 321 for engaging the cover 30 with the base member 20 are provided in a protruding manner at a plurality of locations on the periphery of the cover 30. When the cover 30 is rotated with the tip of the engaging claw 321 locked to the −Z direction side of the engaging projection 212 of the side wall 21 b of the base member 20, the tip of the engaging claw 321 causes the side wall 21 b to move. It is fitted into the engaging hole 215 formed in the base member 20 and fixed to the base member 20.

The back cover 40 is formed of an elastic member such as an elastomer, and has a main piece 41 having a circular shape in plan view, and a tongue piece 42 protruding from four positions of the main piece 41. Further, the main piece 41 is formed with slits 411, 412, 413 through which the power supply lines derived from the above-mentioned lighting circuit unit can be inserted.

The light diffusing member 50 is a hollow triangular pyramid shaped from a plate-shaped base material having a light-transmitting property, and is a substrate so as to cover the three light emitting elements 12 on the surface side of the substrate 11 on which the three light emitting elements 12 are mounted. The light emitted from the three light emitting elements 12 is diffused. The above-mentioned base material is formed of a translucent material such as a translucent resin (for example, a translucent polyester film). In addition, the light diffusion member 50 is a hollow triangular pyramid-shaped main portion 500 having a hole (not shown) formed in its top portion, and is continuously and integrally provided with the main portion 500, and extends along the outer surface of the main portion 500. And an extending portion 524 that extends in a direction toward the top TP1 of the main portion 500 and that is partially opposed to the hole formed in the top TP1 of the main portion 500. As shown in FIG. 3, the main portion 500 has the same shape as the first diffusion plate 51 formed in a plate shape of an equilateral triangle in a plan view, that is, a plate shape of an equilateral triangle in a plan view. The second diffusion plate 52 and the third diffusion plate 53 are formed. The second diffusion plate 52 is continuous with one side of the first diffusion plate 51 on one of the two sides. The third diffusion plate 53 is continuous with one of the two sides that is different from the side of the first diffusion plate 51 with which the second diffusion plate 52 is continuous.

Further, the main part 500 has two extending pieces 522, 523 extending in a direction orthogonal to a side different from the side continuous with the first diffusion plate 51 among the two sides of the second diffusion plate 52. Have. The extending piece 522 is a first extending piece extending from an end on the side of the apex TP1 on a side different from the side continuous with the first diffusion plate 51. In addition, the extending piece 523 extends from an end of the side different from the side continuous with the first diffusion plate 51, which is opposite to the side of the apex TP1. Further, the main part 500 has one extension piece 532 extending from a side of the two sides of the third diffusion plate 53, which is different from the side continuous with the first diffusion plate 51, in a direction orthogonal to the side. .. The extending piece 532 is a second extending piece extending in a direction orthogonal to the side from the position engaging with the extending piece 522 on the side of the apex TP1 on the side different from the side continuous with the first diffusion plate 51. is there.

The extending portion 524 is continuously and integrally formed with the extending piece 522, and extends from the end of the extending piece 522 on the top TP1 side along the side where the extending piece 522 of the second diffusion plate 52 extends. .. Here, the length W1 in the direction along one side where the extension pieces 522, 523 of the second diffusion plate 52 of the extension part 524 shown in FIG. The length is set to intersect with a virtual straight line connecting the top portion TP1 of the member 50. Further, the length and shape of the extending portion 524 are set in consideration of the ease of assembling the light diffusing member 50 or optimizing the kurtosis of the top portion TP1.

Further, the light diffusing member 50 includes a tongue piece 511 continuous with a side of the first diffusing plate 51 facing the top portion TP1, a tongue piece 521 continuous with a side of the second diffusing plate 52 facing the top portion TP1, and a third And a tongue piece 531 continuous with a side of the diffusion plate 53 facing the top portion TP1. The tongue pieces 521 and 531 are provided with through holes 521a and 531a, respectively. As shown in FIG. 1, the light diffusing member 50 is fixed to the substrate 11 by inserting the tip of the rivet 61 inserted into the through holes 521a and 531a into the through hole 11a penetrating the substrate 11. It

As described above, the light diffusing member 50 is formed in the shape of a hollow cone from the first diffusing plate 51, the second diffusing plate 52, and the third diffusing plate 53 having a light transmitting property. Then, the light emitted from the three light emitting elements 12 is diffused in the +Z direction by the first diffusion plate 51, the second diffusion plate 52, and the third diffusion plate 53 of the light diffusion member 50. As a result, the light diffused in the +Z direction is also applied to the shaded portions of the terminal block 13 arranged on the side of the three light emitting elements 12 on the substrate 11.

Next, a method for assembling the light diffusing member 50 according to the present embodiment will be described with reference to FIG. As shown in FIG. 4, the base material 1050 that is the base of the light diffusing member 50 is manufactured by punching a plate material formed of a resin having a light-transmitting property. First, the base material 1050 is valley-folded along the two-dot chain lines VFL1, VFL2, and VFL3 in FIG. 4 so that the portions corresponding to the tongues 511, 521, and 531 are folded back toward the front side of the paper. Next, the base material 1050 is mountain-folded along the lines indicated by alternate long and short dash lines MFL1 and MFL2 in FIG. Then, in the base material 1050, it corresponds to one side where the extension pieces 522 and 523 of the second diffusion plate 52 extend and one side where the extension piece 532 of the third diffusion plate 53 extends. The part and the part are brought into contact with each other. At this time, the extension piece 532 is engaged between the two extension pieces 522 and 523. In this way, the light diffusion member 50 having the triangular pyramid-shaped main portion 500 and the extending portion 524 is completed. As described above, the light diffusion member 50 according to the present embodiment can be easily assembled from the base material 1050 without using an injection molding method and without using a component such as an adhesive material or a screw.

Next, the light distribution characteristics of the illumination device 1 according to the present embodiment will be described in comparison with the light distribution characteristics of the comparative example. For example, as shown in FIG. 5, a lighting device 9001 according to a comparative example includes a light diffusion member 9050 formed of a translucent material in a triangular pyramid shape and having a hole H9 formed at the top TP9. Note that in FIG. 5, the same components as those in the embodiment are denoted by the same reference numerals as those in FIG. 2B. In the case of the illumination device 9001 according to the comparative example, the hole H9 formed in the top portion TP9 of the light diffusion member 9050 functions as a so-called pinhole, and the image formation portions IM1 of the three light emitting elements 12 on the irradiation target surface S1 of the illumination device 9001. Is bright and other parts are relatively dark. On the other hand, in the illumination device 1 according to the present embodiment, as shown in FIG. 6, the light emitted from the hole H1 formed in the top TP1 of the light diffusing member 50 hits the extending portion 524 and is diffused. Therefore, the luminance unevenness on the irradiation target surface S1 of the illumination device 1 is suppressed.

The light diffusing member 50 according to the present embodiment is formed in a hollow triangular pyramid shape from a plate-shaped base material 1050 having a light-transmitting property, and has three light-emitting elements 12 on the surface side on which the substrate 11 is mounted. It is arranged on the substrate so as to cover the light emitting element 12. As a result, the light emitted from the three light emitting elements 12 is diffused in the +Z direction by the light diffusing member 50. Therefore, as shown in FIG. 1, the light is disposed on the side of the three light emitting elements 12 on the substrate 11. The light causing the shadow of the terminal block 13 is also diffused in the +Z direction by the light diffusing member 50, and the light is applied to the shadowed portion, so that the shadow is weakened. Therefore, there is an advantage that the occurrence of luminance unevenness in the entire irradiation target area of the lighting device 1 is suppressed when the lighting device 1 is turned on.

By the way, the light diffusing member 50 according to the present embodiment is manufactured by folding one base material 1050 as described above, and therefore, the first diffusing plate 51, the second diffusing plate 52, and the third diffusing plate 53 are formed. Holes are easily formed on the top TP1 side. On the other hand, according to the illumination device 1 according to the present embodiment, the light diffusion member 50 has the main portion 500 having a triangular pyramid shape and the hole formed at the top, and the extending piece 522 of the main portion 500. An extension portion 524 that is provided continuously and integrally, extends in a direction toward the top portion TP1 along the outer surface of the main portion 500, and has a portion that is arranged to face a hole formed in the top portion TP1 of the main portion 500. With. Thereby, the top portion TP1 side of the first diffusion plate 51, the second diffusion plate 52, and the third diffusion plate 53 is covered with the extending portion 524, so that the first diffusion plate 51 and the second diffusion plate 52 are radiated from the light emitting element 12. And the light leaked from the hole formed on the side of the top portion TP1 of the third diffusion plate 53 is diffused by the extension portion 524. Therefore, it is possible to suppress the occurrence of luminance unevenness due to light leaking from the holes formed on the top TP1 side of the first diffusion plate 51, the second diffusion plate 52, and the third diffusion plate 53.

Further, in the light diffusing member 50 according to the present embodiment, the second diffusing plate 52 has the extending pieces 522 and 523, and the third diffusing plate 53 has the extending piece 532. As a result, the light leaking from the boundary portion between the second diffusion plate 52 and the third diffusion plate 53 to the outside of the light diffusion member 50 is diffused by the extension pieces 522, 523, 532. As a result, it is possible to suppress the occurrence of luminance unevenness in the irradiation target area of the illumination device 1 due to the light leaking to the outside of the light diffusion member 50 from the boundary portion between the second diffusion plate 52 and the third diffusion plate 53. There is.

Further, the length W1 of the extending portion 524 according to the present embodiment in the direction along one side where the extending pieces 522 and 523 of the second diffusion plate 52 extend is the same as the light emitting portion of the light emitting element 12. The length is set to intersect with a virtual straight line connecting the top portion TP1 of the light diffusing member 50. Thereby, the light leaked from the holes formed on the top portion TP1 side of the first diffusion plate 51, the second diffusion plate 52, and the third diffusion plate 53 easily enters the extension portion 524. Therefore, it is possible to suppress the occurrence of luminance unevenness due to light leaking from the holes formed on the top TP1 side of the first diffusion plate 51, the second diffusion plate 52, and the third diffusion plate 53.

Further, each of the first diffusion plate 51, the second light diffusion side 52, and the third light diffusion side 53 according to the present embodiment is a plate shape of a regular triangle in plan view. Then, the second diffusion plate 52 is continuous with one of the two sides of the first diffusion plate 51 at one of the two sides, and the third diffusion plate 53 is out of the two sides. One side is continuous with the other one of the two sides of the first diffusion plate 51. Thereby, as shown in FIG. 4, the shape of the base material 1050 can be set to a shape in which the sides from which the extension pieces 522 and 523 extend and the sides from which the extension piece 532 extend are aligned. .. Therefore, there is an advantage that the base material 1050 that is a base of the light diffusion member 50 can be easily manufactured.

Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations of the above-described embodiments. For example, a light diffusing member having two or more first diffusing plates may be provided. That is, the light diffusion member may have a quadrangular pyramid-shaped or polygonal pyramid-shaped main portion. In this case, the light diffusing member includes two or more first diffusing plates formed in a plate shape of an isosceles triangle in plan view, a second diffusing plate and a third diffusing plate having the same shape as the first diffusing plate, May be included. Here, the second diffusion plate is continuous with one of the two sides having the same length of the first diffusion plate on one side of the two sides having the same length, and the third diffusion plate is , One of the two sides having the same length may be continuous with any one of the two sides having the same length of the first diffusion plate.

Further, as shown in FIG. 7, the light diffusion member 2050 may have a conical main portion 2500. Note that in FIG. 7, the same components as those in the embodiment are designated by the same reference numerals as those in FIG.

In the embodiment, the example in which the light emitting element 12 is an LED has been described, but the light emitting element 12 is not limited to this, and the light emitting element 12 may be another type of light emitting element such as an organic EL (Electro Luminescence) element. Good.

Although the respective embodiments and modifications of the present invention (including those described in the description. The same applies hereinafter) have been described above, the present invention is not limited to these. The present invention includes a combination of the embodiments and the modified examples as appropriate, and a suitably modified version thereof.

INDUSTRIAL APPLICATION This invention is suitable for the illuminating device attached to construction materials, such as a ceiling material and a wall material.

1: Illumination device, 10: Light source unit, 11: Substrate, 11a, 221a, 521a, 531a: Through hole, 11b: Notch part, 12: Light emitting element, 13: Terminal block, 20: Base member, 21: Main body part, 21a, 221b: bottom wall, 21b: side wall, 22: frame part, 22a, 22c: tubular part, 22b: annular part, 23: connecting part, 30: cover, 40: back cover, 41: main piece, 42, 511, 521, 531: tongue piece, 50, 2050: light diffusing member, 51: first diffusing plate, 52: second diffusing plate, 53: third diffusing plate, 61: rivet, 211a: first flat part, 211b. : Rib, 211c: beam, 211d: positioning piece, 211e: rib, 212: engaging protrusion, 213, 321: engaging claw, 212a: curved portion, 213a: second flat portion, 214a: opening portion, 215: engagement Joint hole, 221: Projection part, 231: Lock piece, 232: Ring, 233: Washer, 234: Screw, 235: Nut, 311: Projection part, 411, 412, 413: Slit, 500, 2500: Main part, 522, 523, 532: Extending piece, 524: Extending part, 1050: Base material, H1, H9: Hole, IM1: Imaging part, S1: Irradiation target surface, TP1, TP9: Top part

Claims (8)

Board,
At least one light emitting device mounted on the substrate;
It is formed from a translucent plate-shaped base material in a hollow weight shape and is arranged on the substrate so as to cover the at least one light emitting element on the surface side of the substrate on which the at least one light emitting element is mounted. And a light diffusing member for diffusing light emitted from the at least one light emitting element,
Lighting equipment. The light diffusion member,
A hollow cone-shaped main part with holes formed at the top,
The main portion is provided integrally with the main portion, extending in a direction toward the top portion along an outer surface of the main portion, and at least a part of the extending portion is arranged to face the hole,
The lighting device according to claim 1. The main part is
At least one first diffusion plate formed from a translucent material into a plate shape of an isosceles triangle in plan view;
One of two sides having the same shape as the first diffusion plate and formed of a translucent material and having the same length on one side of the two sides having the same length. A second diffuser plate continuous to one side,
A first extension piece extending from at least an apex-side end of the other side of the two sides having the same length of the second diffusion plate in a direction orthogonal to the other side;
One of two sides having the same shape as the first diffusion plate and formed of a translucent material and having the same length on one side of the two sides having the same length. A third diffuser plate continuous to one side,
A second extension extending in a direction orthogonal to the other side from a position engaging with the first extension piece on the apex side of the other side of the two sides having the same length of the third diffusion plate. With a piece,
The extending portion is
From the end portion of the first extension piece on the apex side, the two sides of the second diffusion plate having the same length extend along the side where the first extension piece extends.
The lighting device according to claim 2. Of the two sides of the extension portion having the same length of the second diffusion plate, the length in the direction along one side extending by the first extension piece is the light emission of the at least one light emitting element. The length is set to intersect with a virtual straight line connecting a portion and the top of the light diffusing member,
The lighting device according to claim 3. The first diffusion plate has a plate shape of a regular triangle in a plan view, and only one exists,
The second diffusion plate has a plate shape of a regular triangle in a plan view, and one side of the two sides is continuous with any one of the two sides of the first diffusion plate,
The third diffusion plate has a plate shape of a regular triangle in a plan view, and one side of the two sides is continuous with the other one side of the two sides of the first diffusion plate.
The lighting device according to claim 3 or 4. A light-transmissive plate-shaped substrate is provided with a main part formed in a hollow weight shape.
Light diffusion member. The main portion has a hole at the top,
The main portion is provided continuously and integrally, extending in a direction toward the top portion along an outer surface of the main portion, further comprising an extending portion at least a part of which is arranged to face the hole,
The light diffusion member according to claim 6. The main part is
At least one first diffusion plate formed from a translucent material into a plate shape of an isosceles triangle in plan view;
One of two sides having the same shape as the first diffusion plate and formed of a translucent material and having the same length on one side of the two sides having the same length. A second diffuser plate continuous to one side,
A first extension piece extending from at least an apex-side end of the other side of the two sides having the same length of the second diffusion plate in a direction orthogonal to the other side;
One of two sides having the same shape as the first diffusion plate and formed of a translucent material and having the same length on one side of the two sides having the same length. A third diffuser plate continuous to one side,
A second extension extending in a direction orthogonal to the other side from a position engaging with the first extension piece on the apex side of the other side of the two sides having the same length of the third diffusion plate. With a piece,
The extending portion is
From the end portion of the first extension piece on the apex side, the two sides of the second diffusion plate having the same length extend along the side where the first extension piece extends.
The light diffusion member according to claim 7.

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