JP5687023B2 - Planar light emitting device - Google Patents

Description

  The present invention relates to a planar light emitting device that is thin and has high light emission uniformity from a light emitting surface.

  Conventionally, as a planar light emitting device aiming at an illumination effect by light emission, an LED (light emitting diode) is used as a light source, and a transparent or translucent light guide is used to guide and diffuse light emitted from the light source. Arranged planar light emitting devices are known. In a planar light emitting device, for example, an edge light system in which LEDs are arranged so that light is incident on the side surface of the light guide, or an L-shaped light guide is incident on one side of the light guide. There are methods such as an L-type method in which the emitted light changes its direction in the light guide and diffuses, and a light source method in the light guide in which LEDs are arranged in the light guide.

  As an example of the planar light emitting device, there is a light emitting device that decorates a logo or mark (design body) such as an emblem of an automobile with light (for example, Patent Document 1 and Patent Document 2). The light emitting device includes a mark main body, a substrate disposed on the back side of the mark main body, an LED mounted on a surface opposite to the mark main body of the substrate, and a light guide, While storing LED in a recessed part, the side surface is made into the light emission surface, and the back surface side is made into the reflective surface formed in the optical axis direction of LED. Here, the planar view shape of the light guide is similar to the planar view shape of the mark body, and the mark body is lit and displayed by the light emitting surface on the side surface of the light guide. In addition, a mortar-shaped recess is provided on the back side of the light guide, and the apex thereof is arranged on the optical axis of the LED. It promotes the uniform distribution of light in the body and tries to make the luminance of light emitted from the light emitting surface uniform.

  Patent Document 3 discloses an edge light type planar light source unit in which an LED serving as a light source is disposed close to a side surface of a light guide. This edge light method has high emission uniformity, but has a relatively low degree of design freedom.

JP 2006-44330 A JP 2006-44329 A Japanese Patent Laid-Open No. 11-306831

  The light-emitting devices of Patent Document 1 and Patent Document 2 described above are light-emitting devices using a light source system in the light guide in which LEDs are disposed in the light guide. In order to make the entire light guide uniform, it is necessary to dispose a plurality of LEDs, resulting in increased processing costs and manufacturing costs. .

  In addition, as shown in FIG. 7A, the light emitting devices of Patent Document 1 and Patent Document 2 have a mortar-shaped concave portion 57 on the back surface side of the light guide 54, in addition to the concave portion 56 that houses the LED 55. Is formed on the optical axis of the LED 55. In such a configuration, a large amount of light at the center of the light emitted from the LED 55 is emitted in the vicinity of the LED 55, so that the LED 55 as shown in FIG. Brightness becomes extremely high in the vicinity, and a plurality of locations S where light rays concentrate in the light guide 54 as shown in FIG. 7D, making it difficult for light to reach the entire light guide 54, as shown in FIG. As in (B), there is a problem that the light emitting device is inferior in light emission uniformity because the central portion of the light emitting surface is extremely bright and dark portions are generated in the peripheral portion.

  In view of such problems, the present invention provides a planar light emitting device that is thin and space-saving without being restricted by the position and number of light sources, and that has high light emission uniformity from the light emitting surface. It is intended to provide.

  In order to achieve the above object, a planar light emitting device according to the present invention has a design shape portion representing a shape of a design, and a design body in which a recess having an open bottom surface is formed in the design shape portion; A flat sheet body disposed below the design body and having substantially the same outer shape as the design body in plan view, disposed on the lower surface side of the sheet body, and disposed on the upper surface of the lower surface of the sheet body And a flat light guide that guides light from the light source, and the light source is disposed in the recess of the design body and close to the light emission surface of the light guide. The provided design body is displayed with light emission.

  According to this configuration, by disposing the light source in the recess of the design shape portion of the design body, it is not necessary to provide an extra space for installing the light source, and the planar light emitting device can be thinned. Thereby, it is applicable also to components with restrictions in installation space, such as an emblem attached to the exterior of a car. Moreover, the freedom degree of arrangement | positioning of a light source becomes remarkably high. Furthermore, compared with the case where it is installed in the light guide, there is no need for processing such as forming a recess for arranging the light source in the light guide, and space can be saved without increasing the manufacturing cost and the number of manufacturing steps.

  In this planar light emitting device, it is preferable that a through-hole penetrating in the vertical direction is formed in the light guide at a position directly below the light source. In this case, since the through hole is formed immediately below the light source, the light emitted from the light source is diffracted and diffused into the light guide body at the side surface of the through hole, and at the same time, penetrates the light guide body. Therefore, of the light emitted from the light source, the light near the center of the light source passes through the through hole and does not emit light from the light emitting surface of the light guide. Accordingly, it is possible to prevent the light emission amount of the portion near the light source of the light guide from becoming larger than that of other portions, and to emit light uniformly from the entire light emitting surface of the light guide.

  The through hole has a hole diameter in the range of 0.4 to 1.0 mm on the upper surface of the light guide and a hole diameter in the range of 1.0 to 4.0 mm on the lower surface, and the inner surface of the hole is the light guide. It may have a substantially pyramid shape in which the hole diameter gradually increases downward. In this case, since the through-hole has an inner surface of the hole that spreads in a substantially conical shape from the upper surface to the lower surface of the light guide, the light emitted from the light source can be used uniformly and dispersed in the light guide. Is possible. Preferably, the inner surface of the through hole has a curved shape that is convex downward. Therefore, it is possible to further increase the utilization efficiency of the light emitted from the light source.

  In the present invention, since the light source is disposed in the recess of the design shape portion of the design body, it can be thin and space-saving, and the through hole of the light guide is formed immediately below the light source. The uniformity of light emission from the light emitting surface can be increased.

It is a disassembled perspective view which shows the structure of the planar light-emitting device concerning this invention. It is the longitudinal cross-sectional view cut | disconnected by the II-II line so that the logo-shaped part of the planar light-emitting device of FIG. It is a top view which shows the sheet | seat body applied to the planar light-emitting device in this invention. It is a fragmentary sectional view which shows the light guide applied to the planar light-emitting device in this invention. It is a side view which shows the light source and light guide which are applied to the planar light-emitting device in this invention. (A) is a partial side view of the planar light emitting device according to the present invention, and FIGS. 6 (B) to 6 (D) show the simulation results. (A) is a partial side view of a conventional planar light emitting device, and FIGS. 6 (B) to 6 (D) show the simulation results.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view in which a surface light emitting device 1 according to the present invention is applied to a design body 2 such as an emblem logo disposed on an outer surface of an automobile to decorate a vehicle, for example. In addition, you may apply the name and logo marks, such as a vehicle model and a brand, to the design body 2. FIG.

  The planar light emitting device 1 in FIG. 1 is formed by laminating a design body 2, a light source 5, a sheet body 3, and a light guide body 4 in this order. The sheet body 3 and the light guide 4 have a flat disk shape. The design body 2 has a logo shape portion of a circle A that encloses an alphabet A, which is an example of a design shape portion 2c that represents the shape of the design in a plan view, and the portions other than the logo shape portion 2c are perforated and penetrated. It is molded into the shape. The design body 2 is obtained by injection molding a thermoplastic resin such as an ABS resin, and the surface of the ABS resin molded body is coated in a metallic manner by painting, printing, vapor deposition, plating, or the like.

  When the planar light emitting device 1 is viewed from the design body 2 side (above), a portion of the design body 2 other than the logo-shaped portion 2c is partially exposed to the sheet body 3, so that the sheet body 3 is visually recognized. it can. Here, the light guide 4 is substantially entirely covered with the design body 3 and the sheet body 3.

  2 is a vertical cross-sectional view taken along the line II-II in FIG. 1 so that the logo-shaped portions 2c of the design body 2 of the planar light emitting device 1 are bilaterally symmetric in plan view. The logo-shaped portion 2c of the design body 2 is formed with a recess (space storage portion) 2a having a lower surface opened therein, and the weight can be reduced by the amount of the recess 2a. The design body 2 is formed to have a thickness of about 1.5 mm in order to reduce the weight and secure required strength and durability. In addition to this, a thermoplastic resin such as polypropylene or polyethylene may be used as the material of the design body 2, or a thermosetting resin or metal may be used.

  The light source 5 is disposed in the recess 2a of the logo shape part (design shape part) 2c of the design body 2 at a position above the sheet body 3. Thereby, since a new space for arranging the light source 5 becomes unnecessary, the planar light emitting device 1 can be adopted even when the installation space is limited. In addition, as compared with the conventional light emitting device in which the light source is disposed on the side surface of the light guide, the position restriction of the light source 5 is reduced, and the degree of freedom in design is increased. As the light source 5, a surface mount type LED (light emitting diode) mounted on a glass epoxy resin substrate is preferably used.

  In this example, only one light source 5 is disposed at substantially the center of the planar light emitting device 1. However, the present invention is not limited to this, and a plurality of light sources 5 may be installed. If it is in the recess 2a, it can be installed at an arbitrary position.

  FIG. 3 shows a plan view of the sheet body 3 as viewed from above. The sheet body 3 is a molded body obtained by injection molding a thermoplastic resin such as polycarbonate resin, and is formed into a thin disk shape so as to be substantially the same as the circular shape that is the outer shape of the design body 2. It arrange | positions so that the penetration part 2b penetrated except the opening of the recess 2a and a logo may be shielded. In the sheet body 3, a through hole (light passage hole) 3 a is formed immediately below the light source 5. Light emitted from the light source 5 is applied to the light guide 4 without being reflected by the sheet 3 through the light passage hole 3a. It is preferable that the light passage hole 3a is formed so as to be in a range equal to or greater than the effective light emitting area (FIG. 5) of the light source 5 because the utilization efficiency of light emitted from the light source can be improved. Further, the sheet body 3 is formed with an insertion hole 3 b for allowing a harness extending from the light source 5 to pass therethrough.

  The back surface of the sheet body 3 is colored by printing or painting in the order of black, blue, and white from the inside. The black color is partially colored in the portion corresponding to the penetrating portion 2b of the design body 2 of the sheet body 3, that is, the portion visible from the outside of the planar light emitting device 1, except for the light emitting portion 3c. The light guided by the light body 4 is shielded, and a light shielding portion 3 d that does not emit light to the outside of the planar light emitting device 1 is formed on the sheet body 3. The blue color is formed on the entire back surface of the sheet body 3 to transmit the light guided by the light guide 4, and the light emitting section 3 c that emits blue around the logo-shaped section 2 c is formed on the sheet body 3. White color reflects the light that is colored on the entire back surface of the sheet body 3 and guided from the light guide body 4, suppresses the light from being attenuated in the light shielding portion 3 d, and increases the light use efficiency. In addition, there is an effect of improving the visibility of the light emitting portion 3c when the light is not lit during the daytime.

  The light guide 4 in FIG. 1 is a molded body obtained by injection molding or the like of a thermoplastic resin such as acrylic (PMMA) resin, and is formed so that the surface thereof is approximately the same size as the sheet body 3. It arrange | positions so that the sheet | seat body 3 may be contact | connected on the opposite side to the side which faces the design body 2 of the body 3. FIG. The upper surface of the light guide 4 is the light emitting surface 4c. The light guide 4 is formed with a through hole 4a penetrating in the vertical direction. The through hole 4a is formed at a position directly below the light source 5 and the light passage hole 3a of the sheet 3 as shown in FIG. Has been. That is, the light source 5 is disposed in the vicinity of the light emitting surface 4 c of the light guide 4. The separation distance between the light source 5 and the light emitting surface 4c of the light guide 4 is preferably 1.0 mm or less, more preferably 0.5 mm or less. Further, the light guide 4 is formed with an insertion hole 4b through which a harness extending from the light source 5 is passed (FIG. 1).

  The light guide 4 can be replaced with polycarbonate resin, polypropylene resin, polyethylene resin, silicon resin, etc. in addition to the acrylic resin. Moreover, even if it is not transparent resin, it can use even translucent.

  As shown in FIG. 4, the through hole 4 a of the light guide 4 has a larger opening diameter on the lower surface opposite to the light source 5 than the opening diameter of the upper surface on the light source 5 side. It has a substantially pyramid shape in which the hole diameter gradually increases downward. The through-hole 4a has a hole diameter D1 of the opening 4aa on the upper surface (surface on the light source 5 side) of the light guide 4 of 0.4 to 1.0 mm, more preferably 0.6 to 0.8 mm. It is emitted from the light source 5 that the hole diameter D2 of the opening 4bb on the lower surface (the surface opposite to the light source 5) is 1.0 to 4.0 mm, more preferably 2.0 to 3.0 mm. This is suitable in terms of increasing the light utilization efficiency.

  By providing the through hole 4a, the light emitted from the light source 5 has its central portion discarded through the through hole 4a, and the surrounding portion is diffracted by the inner surface of the through hole 4a to guide the light. The light is guided into the body 4. Accordingly, the planar light emitting device 1 in which light is dispersed throughout the light guide 4 while suppressing the light emission from the vicinity of the light source 5 and the light emission uniformity in the entire light emitting surface 4c of the light guide 4 is improved. It can be realized.

  Moreover, it is more preferable that the inner surface of the through-hole 4a has a bulging shape (curved shape) so as to be convex inward, and by using such a shape, the utilization efficiency of light emitted from the light source 5 can be improved. It can be further increased. In this case, the light incident on the light guide 4 enters the opening 4aa on the light source 5 side of the through hole 4a in the central portion, and the light passing through the opening 4ab on the opposite side of the light source 5 passes through as it is. Then, the light that is discarded and hits the inner surface of the light guide 4 is diffracted, and the direction from the light emitting direction of the light source 5 is changed to guide the light in the light guide 4.

  The back surface of the light guide 4 is subjected to a dot pattern or a textured process, or white printing or painting. With such a configuration, light is reflected on the back surface of the light guide 4, so that the light utilization efficiency can be increased.

  As shown in FIG. 5, the through-hole 4 a is preferably provided in an area that is equal to or within the effective light emitting area (LED light emitting portion) of the light source 5. Specifically, the opening 4aa on the light source 5 side has a shape that does not exceed the size of the effective light emitting area of the light source 5, and the opening 4ab on the opposite side of the light source 5 has a half-value angle determined by the directivity characteristics of the light source 5. It is preferable not to exceed the size projected on the surface on the light source 5 side by the axis defined by.

Examples of the planar light emitting device according to the present invention will be described below.
(Example 1)
As the light source, only one LED NSSW64 (3.2 × 2.8 mm, half-value angle 120 °) manufactured by Nichia Chemical was used. As the light guide, a transparent acrylic (PMMA) resin having a thickness of 0.8 mm was used, and a dot pattern for uniformly emitting light within the surface was applied to the back surface of the light guide with a laser. Also, the inner surface of the hole is convex downward so that the hole diameter D1 = 0.6 mm on the surface of the light guide, that is, the LED side surface, and the hole diameter D2 = 1.2 mm on the rear surface of the light guide. An opening having an inclined portion of (mm) is formed. In addition, a 0.5 mm gap was provided between the light emitting surface of the LED and the light guide in consideration of shrinkage and expansion due to temperature change.

  On the surface of the light guide, that is, on the side where the LED is disposed, a 0.5 mm thick sheet body that is coated or printed so as to correspond to the logo design is arranged, and further, on the upper surface side thereof The design body in which the logo-shaped part is formed in a convex shape is arranged. The design body is formed by injection molding of an ABS resin, and a recess is formed in the convex logo shape portion so as to have a space of about 5 mm in width. The LED is a surface mount type mounted on a glass epoxy resin substrate having a thickness of 1.0 mm, and the LED is disposed in a recess of a logo shape portion of the design body.

(Example 2)
As the light source, only one LED NSSW64 (3.2 × 2.8 mm, half-value angle 120 °) manufactured by Nichia Chemical was used. As the light guide, transparent acrylic (PMMA) resin having a thickness of 0.8 mm was used, and a scatterer was disposed on the back surface of the light guide to uniformly emit light within the surface. Also, the inner surface of the hole is convex downward so that the hole diameter D1 = 0.6 mm on the surface of the light guide, that is, the LED side surface, and the hole diameter D2 = 1.2 mm on the rear surface of the light guide. An opening having an inclined portion of (mm) is formed. In addition, a 0.5 mm gap was provided between the light emitting surface of the LED and the light guide in consideration of shrinkage and expansion due to temperature change.

  A sheet body with a thickness of 0.5 mm on which the logo is designed is arranged on the surface of the light guide, that is, the side on which the LEDs are arranged, and the same logo as the logo on the sheet body is arranged on the upper surface side. A design body formed in a convex shape was arranged. The design body is formed by injection molding of an ABS resin, and a recess is formed in the convex logo shape portion so as to have a space of about 5 mm in width. The LED is a surface mount type mounted on a glass epoxy resin substrate having a thickness of 1.0 mm, and the LED is disposed in a recess of a logo shape portion of the design body.

Example 3
As the light source, only one LED NSSW64 (3.2 × 2.8 mm, half-value angle 120 °) manufactured by Nichia Chemical was used. As the light guide, a polycarbonate (PC) resin having a thickness of 0.8 mm was used, and a dot pattern for uniformly emitting light within the surface was applied to the back surface of the light guide with a laser. Further, the inner surface of the hole is convex downward so that the hole diameter D1 = 0.6 mm on the surface of the light guide, that is, the LED side surface, and the hole diameter D2 = 1.2 mm on the back surface of the light guide. An opening having an inclined portion of (mm) is formed. In addition, a 0.5 mm gap was provided between the light emitting surface of the LED and the light guide in consideration of shrinkage and expansion due to temperature change.

  A sheet body with a thickness of 0.5 mm on which the logo is designed is arranged on the surface of the light guide, that is, the side on which the LEDs are arranged, and the same logo as the logo on the sheet body is arranged on the upper surface side. A design body formed in a convex shape was arranged. The design body is formed by injection molding of an ABS resin, and a recess is formed in the convex logo shape portion so as to have a space of about 5 mm in width. The LED is a surface mount type mounted on a glass epoxy resin substrate having a thickness of 1.0 mm, and the LED is disposed in a recess of a logo shape portion of the design body.

Example 4
As the light source, only one LED NSSW64 (3.2 × 2.8 mm, half-value angle 120 °) manufactured by Nichia Chemical was used. As the light guide, a transparent acrylic (PMMA) resin having a thickness of 0.8 mm was used, and a dot pattern for uniformly emitting light within the surface was applied to the back surface of the light guide with a laser. Also, the inner surface of the hole is convex downward so that the hole diameter D1 = 0.6 mm on the surface of the light guide, that is, the LED side surface, and the hole diameter D2 = 4.1 mm on the back surface of the light guide. An opening having an inclined portion of (mm) is formed. In addition, a 0.5 mm gap was provided between the light emitting surface of the LED and the light guide in consideration of shrinkage and expansion due to temperature change.

  A sheet body with a thickness of 0.5 mm on which the logo is designed is arranged on the surface of the light guide, that is, the side on which the LEDs are arranged, and the same logo as the logo on the sheet body is arranged on the upper surface side. A design body formed in a convex shape was arranged. The design body is formed by injection molding of an ABS resin, and a recess is formed in the convex logo shape portion so as to have a space of about 5 mm in width. The LED is a surface mount type mounted on a glass epoxy resin substrate having a thickness of 1.0 mm, and the LED is disposed in a recess of a logo shape portion of the design body.

(Example 5)
As the light source, only one LED NSSW64 (3.2 × 2.8 mm, half-value angle 120 °) manufactured by Nichia Chemical was used. As the light guide, a transparent acrylic (PMMA) resin having a thickness of 0.8 mm was used, and a dot pattern for uniformly emitting light within the surface was applied to the back surface of the light guide with a laser. In addition, a hole with a linear inner surface is formed so that the hole diameter D1 = 3.2 mm on the surface of the light guide, that is, the LED side surface, and the hole diameter D2 = 4.1 mm on the back surface of the light guide. doing. In addition, a 0.5 mm gap was provided between the light emitting surface of the LED and the light guide in consideration of shrinkage and expansion due to temperature change.

  On the surface of the light guide 4, that is, on the side where the LED is disposed, a 0.5 mm thick sheet body on which the logo is designed is disposed, and on the upper surface side, the same logo as the logo on the sheet body A design body having a convex shape is arranged. The design body is formed by injection molding of an ABS resin, and a recess is formed in the convex logo shape portion so as to have a space of about 5 mm in width. The LED is a surface mount type mounted on a glass epoxy resin substrate having a thickness of 1.0 mm, and the LED is disposed in a recess of a logo shape portion of the design body.

(Comparative Example 1)
As the light source, only one LED NSSW64 (3.2 × 2.8 mm, half-value angle 120 °) manufactured by Nichia Chemical was used. As the light guide, a transparent acrylic (PMMA) resin having a thickness of 0.8 mm was used, and a dot pattern for uniformly emitting light within the surface was applied to the back surface of the light guide with a laser. A sheet body with a thickness of 0.5 mm on which the logo is designed is arranged on the surface of the light guide, that is, the side on which the LEDs are arranged, and the same logo as the logo on the sheet body is placed on the upper surface side A design body formed in a convex shape was arranged. The design body is formed by injection molding of an ABS resin, and a recess is formed in the convex logo shape portion so as to have a space of about 5 mm in width. The LED is a surface-mount type mounted on a glass epoxy resin substrate having a thickness of 1.0 mm, and the LED is arranged on the side of the light guide, and light is irradiated to the side of the light guide. Arranged.

Table 1 shows the results of observing the appearance of illumination by the planar light emitting devices according to Examples 1 to 5 and Comparative Example 1. About Examples 1-4, it confirmed that a logo shape shines uniformly and confirmed that the performance substantially equivalent to the comparative example 1 which is a conventional edge type planar light-emitting device was acquired. About Example 5, the result was a little inferior in appearance.

  FIG. 6A shows a partial side view of the planar light emitting device 1, and FIGS. 6B to 6D show the simulation results. Both the through-hole 4a in the light guide 4 in FIG. 6A and the concave portion 57 in the light guide 54 in FIG. 7A, which is a conventional light emitting device, diffract and guide the light emitted from the light source. Although it is the same in that it aims at guiding light into the light body, the through-hole 4a formed in the light guide 4 of the present invention is a through-opening that opens on both the light source 5 side and the opposite side of the light source 5. In contrast, the concave portion 57 of the conventional light guide 54 has a space formed in the middle of the light guide 54 in the thickness direction and opens to the opposite side of the light source 5.

  As shown in FIG. 6 (D), the light guide 4 according to the present invention has a relatively uniform light beam compared to the conventional light guide 54 having the concentrated light spot S as shown in FIG. 7 (D). In addition, as shown in FIG. 6C, the light guide 4 according to the present invention concentrates light around the recess 57 as shown in FIG. 7C, and the luminance near the light source 54 is higher than that of other parts. Compared with the conventional light guide 54 that is significantly higher and inferior in uniformity, the central part of the light emitted from the light source 4 by the through hole 4a is disposed at a position directly below the light source 5, and the surrounding light is guided. Since the light is guided to the entire body 4, the average luminance is high, and it is possible to emit light more uniformly from the light emitting surface 4 c of the light guide 4 as shown in FIG.

  The planar light-emitting device of the present invention can be thin and space-saving without being restricted by the position and number of light sources, and can enhance the light emission uniformity from the light-emitting surface and display the design body in a light-emitting manner. Therefore, it can be useful not only for decorating vehicles but also for decorating various devices.

  As described above, the preferred embodiment of the present invention has been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Included within the scope of the invention.

1: planar light emitting device 2: design body 2a: recess 2b: penetrating portion 2c: design shape portion (logo shape portion)
3: Sheet body 3a: Through hole (light passage hole)
3b: Insertion hole 3c: Light emitting part 3d: Light shielding part 4: Light guide 4a: Through hole 4c: Light emitting surface 5: Light source (LED)

Claims (5)

A design body having a design shape portion representing the shape of the design and having a recess having a lower surface opened in the design shape portion, and an outer shape of the design body arranged in a plan view and disposed below the design body A flat sheet body having substantially the same outer shape, and a flat plate that is disposed on the lower surface side of the sheet body, has a light emitting surface in contact with the entire lower surface of the sheet body, and guides light from the light source And a light guide
A planar light emitting device for emitting and displaying a design body, wherein the light source is disposed in the recess of the design body in the vicinity of the light emitting surface of the light guide. A design body having a design shape part representing the shape of the design, a design body in which a recess having a lower surface is formed in the design shape part, and a light emitting surface on the upper surface, disposed below the design body, A flat light guide that guides light from the light source,
A planar light emitting device for emitting and displaying a design body, wherein the light source is disposed in the recess of the design body in the vicinity of the light emitting surface of the light guide. In the light guide at a position immediately below the light source, a planar light emitting device according to claim 1 or 2 through-holes are formed to penetrate in the vertical direction. The through hole has a hole diameter of 0.4 to 1.0 mm on the upper surface of the light guide and a hole diameter of 1.0 to 4.0 mm on the lower surface, and the inner surface of the hole is below the light guide. The planar light-emitting device according to claim 3 , wherein the planar light-emitting device has a substantially conical shape in which a hole diameter gradually increases toward the surface. The planar light-emitting device according to claim 4 , wherein an inner side surface of the through hole has a curved shape that is convex downward.

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