JP6587506B2 - Lighting device - Google Patents

Description

  The present invention relates to a thin plate-like lighting device having a small thickness.

  The present applicant has proposed a flat illuminating device designed so that the brightness of the light exit surface is uniform as a whole including the peripheral portion (see, for example, Patent Document 1). The illumination device described in Patent Document 1 is formed in a square flat plate shape. The lighting device includes a light guide plate, a plurality of LED light sources that emit light toward an end surface of the light guide plate, an LED substrate on which the plurality of LED light sources are mounted, and one side of the light guide plate in the thickness direction of the light guide plate A diffusion plate that diffuses light emitted from the light guide plate and a reflection plate that is disposed on the other side of the light guide plate in the thickness direction of the light guide plate.

JP 2014-150049 A

  The inventor of the present application is considering increasing the area of the light emission surface of the illumination device by forming the illumination device described in Patent Document 1 into a flat plate shape such as a rectangle and increasing the size. However, when the illuminating device is enlarged so that the area of the light emission surface becomes large, if the rigidity of the illuminating device is low, for example, the other end side of the illuminating device with respect to one end side of the illuminating device formed in a rectangular flat plate shape There is a possibility that the amount of bending of the material becomes large. In addition, for example, when the amount of bending of the other end side of the lighting device with respect to the one end side of the lighting device becomes large, there is a possibility that luminance unevenness occurs on the light exit surface of the lighting device.

  Accordingly, an object of the present invention is to provide a lighting device that can ensure rigidity even when the area of a light exit surface is widened in a thin flat plate lighting device.

In order to solve the above-described problems, an illumination device of the present invention includes a light guide plate and a light source that is arranged to face the end surface of the light guide plate and emits light toward the end surface, and in the thickness direction of the light guide plate. When one side is the first direction, the diffusion plate is disposed on the first direction side of the light guide plate and diffuses the light emitted from the light guide plate, and the light guide plate and the light source are formed in a flat box shape having an opening on the first direction side. And a reinforcing frame disposed between the bottom surface of the case and the light guide plate and accommodated in the case. The opening on the first direction side of the case is closed by the diffusion plate. Is provided with a projecting portion that is disposed at a position facing at least a portion along the end surface facing the light source at the peripheral portion of the light emitting surface that is a surface on the first direction side of the light guide plate, and projects toward the light guide plate. is this which is secured to the protrusion by a screw The features.

The illumination device of the present invention includes a reinforcing frame that is disposed between the bottom surface of the case and the light guide plate and is accommodated in the case. Therefore, in the present invention, it is possible to ensure the rigidity of the lighting device even if the area of the light emission surface of the lighting device is widened in a thin flat plate lighting device. Further, in the present invention, the diffusion plate is disposed at a position facing at least a portion along the end surface facing the light source of the peripheral portion of the light emitting surface that is the surface on the first direction side of the light guide plate, and toward the light guide plate. Since the projecting portion is provided and the frame is fixed to the projecting portion by a screw, the screw for fixing the frame to the diffusion plate can be disposed on the thick projecting portion. Therefore, the screw becomes inconspicuous when the light exit surface of the diffuser plate is viewed from the light exit surface of the diffuser plate (that is, the light exit surface of the illumination device). Further, since the frame is fixed to the projecting portion of the diffusion plate and the frame can be fixed to the diffusion plate at a position closer to the outer peripheral surface of the diffusion plate, the rigidity of the lighting device can be increased.

  In the present invention, the light guide plate and the diffusion plate are formed so that the shape when viewed from the thickness direction of the light guide plate is a rectangular shape, and the frame is a flat frame portion formed in a rectangular frame shape. It is preferable to provide a flat bracing portion that is formed in an X shape and connects the diagonals of the frame portion. If comprised in this way, it will become possible to reduce a weight of an illuminating device compared with the case where a flame | frame is formed in the rectangular flat plate shape. Further, according to the study by the inventors of the present application, when the area of the frame when viewed from the thickness direction of the frame (the frame portion formed in a flat plate shape, the thickness direction of the bracing portion) is constant, the rectangular frame When the frame is configured by the frame portion formed in a shape and the bracing portion that connects the diagonals of the frame portion, the rigidity of the frame can be effectively increased.

  In the present invention, the illumination device preferably includes a light source holding member that holds the light source, and the light source holding member is preferably in contact with the frame. If comprised in this way, it will become possible to transmit the heat which generate | occur | produces with a light source to a flame | frame via a light source holding member. Therefore, it is possible to efficiently dissipate heat generated by the light source.

  In this case, the light guide plate and the diffusion plate are formed so that the shape when viewed from the thickness direction of the light guide plate is rectangular, and the light sources are arranged so as to face each of the four end faces of the light guide plate. The frame preferably includes a flat frame portion formed in a rectangular frame shape and a flat bracing portion formed in an X shape and connecting diagonals of the frame portions. When the light source is arranged so as to face each of the four end faces of the light guide plate, the heat of the light source transmitted to the frame through the light source holding member tends to concentrate on the diagonal part of the frame part, If comprised in this way, it will become possible to dissipate efficiently the heat | fever concentrated on the diagonal part of a frame part using the flat bracing part which connects the diagonals of a frame part. Moreover, if comprised in this way, it will become possible to reduce a weight of an illuminating device compared with the case where a flame | frame is formed in the rectangular flat plate shape. Further, according to the study of the present inventor, when the area of the frame when viewed from the thickness direction of the frame is constant, the brace that connects the diagonals of the frame part and the frame part formed in a rectangular frame shape When the frame is constituted by the portions, the rigidity of the frame can be effectively increased.

  In the present invention, the frame is preferably formed of an aluminum alloy. With this configuration, the frame can be reduced in weight. Also, with this configuration, the thermal conductivity of the frame increases, so that the heat generated by the light source can be more efficiently dissipated when the light source holding member that holds the light source is in contact with the frame. It becomes possible.

  As described above, according to the present invention, it is possible to ensure the rigidity of the lighting device even when the area of the light exit surface of the lighting device is widened in a thin flat plate lighting device.

It is a perspective view which shows the illuminating device concerning embodiment of this invention from the front side. It is a front view for demonstrating the usage example of the illuminating device shown in FIG. It is a perspective view which shows the illuminating device shown in FIG. 1 from the back side. It is a disassembled perspective view of a one part structure of the illuminating device shown in FIG. It is a rear view of the state which removed the case from the illuminating device shown in FIG. It is sectional drawing of the EE cross section of FIG. It is a graph which shows angle distribution of the scattered light intensity by a single true spherical particle. It is a figure for demonstrating structures, such as a light-guide plate and a board | substrate shown in FIG. 4, from the back side. FIG. 9 is an exploded perspective view of a part of the light guide plate, the substrate, the light source holding member, and the like shown in FIG. 8. It is an enlarged view of the G section of FIG. It is a figure for demonstrating the structure of the HH cross section of FIG. It is a figure for demonstrating the structure of the JJ cross section of FIG. It is sectional drawing of the KK cross section of FIG. It is sectional drawing of the NN cross section of FIG. It is a figure for demonstrating the path | route of the light until the light inject | emitted from the light source in the illuminating device shown in FIG. 1 is inject | emitted from the light emission surface of a diffusion plate. It is a figure for demonstrating the structure of the protrusion part concerning other embodiment of this invention. It is a figure for demonstrating the structure of the protrusion part concerning other embodiment of this invention. It is a figure for demonstrating the structure of the light-guide plate concerning other embodiment of this invention. It is a figure for demonstrating the structure of the light-guide plate concerning other embodiment of this invention. It is a front view of the frame concerning other embodiments of the present invention. It is a figure for demonstrating the structure of the light source holding member concerning other embodiment of this invention. It is a figure for demonstrating the structure of the light source holding member concerning other embodiment of this invention. It is a figure for demonstrating the structure of the light source holding member concerning other embodiment of this invention. (A) is a graph for demonstrating the brightness distribution of the light emission surface of the illuminating device concerning other embodiment of this invention, (B) is based on other embodiment of this invention. It is a graph for demonstrating distribution of the brightness of the light emission surface when using it combining two illuminating devices. It is a figure for demonstrating the arrangement position of the light source concerning other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Whole structure of lighting device)
FIG. 1 is a perspective view showing a lighting device 1 according to an embodiment of the present invention from the front side. FIG. 2 is a front view for explaining an example of use of the lighting device 1 shown in FIG. FIG. 3 is a perspective view showing the lighting device 1 shown in FIG. 1 from the back side. FIG. 4 is an exploded perspective view of a part of the configuration of the lighting device 1 shown in FIG. FIG. 5 is a rear view of the lighting device 1 shown in FIG. 3 with the case 9 removed. 6 is a cross-sectional view taken along the line EE of FIG.

  The illuminating device 1 of this embodiment is a light emitting device designed so that the brightness of the light exit surface 3a of the illuminating device 1 is uniform as a whole including the peripheral portion, and is a thin flat plate (flat panel shape). Is formed. Specifically, the illumination device 1 is formed in a rectangular flat plate shape. This lighting device 1 is used alone. Or this illuminating device 1 is used combining multiple sheets. For example, as shown in FIG. 2 (A), two lighting devices 1 are combined in a rectangular shape, or as shown in FIG. 2 (B), four lighting devices 1 are combined in a rectangular shape. Or used. Moreover, the illuminating device 1 is installed and used for the indoor wall surface as an illuminating device which served as an interior, for example. Three lighting devices 1 may be used in combination, or five or more lighting devices 1 may be used in combination.

  In the following description, the thickness direction of the lighting device 1 (the Z direction in FIG. 1 and the like) is referred to as “front-rear direction”, and the longitudinal direction of the rectangular lighting device 1 among the directions orthogonal to the front-rear direction (FIG. 1). X direction) is referred to as “left-right direction”, and the short side direction (Y direction in FIG. 1 and the like) of the lighting device 1 orthogonal to the front-rear direction and the left-right direction is referred to as “vertical direction”. In addition, the front side (the Z1 direction side in FIG. 1 and the like) of the lighting device 1 in the front-rear direction is the “front” side, and the back side (the Z2 direction side in FIG. 1 and the like) of the lighting device 1 that is the opposite side. “Back (back)” side.

  The lighting device 1 includes a light guide plate 2, a diffusion plate 3 that is disposed on the front side of the light guide plate 2 and diffuses light emitted from the light guide plate 2, a reflection sheet 4 that is disposed on the rear side of the light guide plate 2, and a reflection sheet 4. And a reinforcing frame 5 disposed on the rear side of the frame. In addition, the lighting device 1 includes a plurality of light sources 6 (see FIG. 6) that emit light toward the end surfaces 2 a and 2 b of the light guide plate 2, a substrate 7 on which the plurality of light sources 6 are mounted, and the substrate 7. And a light source holding member 8 that holds the light source 6. Furthermore, the lighting device 1 includes a case 9 in which the light guide plate 2, the reflection sheet 4, the frame 5, the light source 6, the substrate 7, and the light source holding member 8 are accommodated. In FIG. 4, the light source 6 is not shown.

  The light guide plate 2 is formed in a rectangular flat plate shape, and is arranged so that the thickness direction of the light guide plate 2 matches the front-rear direction. That is, the front-rear direction is the thickness direction of the light guide plate 2, and the light guide plate 2 is formed so that the shape when viewed from the front-rear direction is rectangular. The light guide plate 2 is arranged so that the longitudinal direction of the light guide plate 2 formed in a rectangular shape coincides with the left-right direction. The light guide plate 2 is formed with two end surfaces 2a orthogonal to the vertical direction and two end surfaces 2b orthogonal to the horizontal direction (see FIG. 4). The front surface of the light guide plate 2 is a light exit surface 2 c of the light guide plate 2. A specific configuration of the light guide plate 2 will be described later. Note that the forward direction (Z1 direction) of the present embodiment is a first direction that is one of the thickness directions of the light guide plate 2.

  The diffusing plate 3 is formed in a rectangular substantially flat plate shape, and is arranged so that the thickness direction of the diffusing plate 3 coincides with the front-rear direction. That is, the diffusion plate 3 is formed so that the shape when viewed from the front-rear direction is a rectangular shape. The diffusion plate 3 is arranged so that the longitudinal direction of the diffusion plate 3 formed in a rectangular shape coincides with the left-right direction. The front surface of the diffusion plate 3 is a light exit surface 3 a of the diffusion plate 3. The light emission surface 3 a is a light emission surface of the lighting device 1. When the light diffusing plate 3 is viewed from the front in front of the light exit surface 3a (that is, when viewed from the direction orthogonal to the light exit surface 3a), the diffusion plate 3 is in the outer shape of the light exit surface 3a. The size is such that the components of the lighting device 1 can be accommodated. A specific configuration of the diffusion plate 3 will be described later.

  The reflection sheet 4 is formed of a material having a high reflectance such as an aluminum foil, for example. The reflection sheet 4 is formed in a rectangular shape so as to cover the entire rear surface (back surface) of the light guide plate 2. The front surface of the reflection sheet 4 is a reflection surface 4 a that reflects light traveling through the light guide plate 2. The reflection sheet 4 is disposed so as to be in close contact with the rear surface of the light guide plate 2. For example, the reflection sheet 4 is attached to the rear surface of the light guide plate 2, and light traveling in the light guide plate 2 is reflected by the reflection surface 4 a. Instead of the reflective sheet 4, a reflective plate formed in a thin flat plate shape may be disposed on the rear side of the light guide plate 2, or a reflective coating is applied to the rear surface of the light guide plate 2 instead of the reflective sheet 4. May be.

  The frame 5 is formed of a metal plate having a high thermal conductivity. The frame 5 of this embodiment is formed of a lightweight aluminum alloy, and the color of the surface of the frame 5 is silver. The frame 5 is formed in a flat plate shape in which the outer shape of the frame 5 is rectangular when viewed from the front-rear direction. Specifically, the frame 5 includes a flat frame portion 5a formed in a rectangular frame shape and a flat bracing portion 5b formed in an X shape and connecting diagonals of the frame portion 5a. Yes. The frame 5 is arranged so that the thickness direction of the frame 5 coincides with the front-rear direction. The frame 5 is arranged so that the longitudinal direction of the frame portion 5a having a rectangular frame shape coincides with the left-right direction. The frame 5 is disposed so as to be in close contact with the rear surface of the reflection sheet 4.

  The light source 6 is an LED (Light Emitting Diode) light source, and is mounted on the substrate 7 as described above. Each of the LED elements constituting the light source 6 is a white LED, and the light source 6 emits white light. The light source 6 is disposed so as to face the end surfaces 2 a and 2 b of the light guide plate 2. Specifically, the light source 6 is arranged so that the centers of the end faces 2a and 2b in the front-rear direction and the center of the light source 6 are substantially coincided with each other in the front-rear direction. In this embodiment, a plurality of light sources 6 are arranged so as to face each of the four end faces 2a, 2b of the light guide plate 2. That is, a plurality of light sources 6 are arranged along each of the four end surfaces 2 a and 2 b of the light guide plate 2. The light source 6 may be a package of a red LED element, a green LED element, and a blue LED element. In this case, the light source 6 can emit light of various colors.

  The substrate 7 is a flexible printed circuit board (FPC (Flexible Printed Circuits)). As shown in FIG. 4, the substrate 7 includes an elongated strip-shaped light source mounting portion 7a and an elongated strip-shaped circuit connection portion 7b connected to the light source mounting portion 7a so as to be orthogonal to the light source mounting portion 7a. A plurality of light sources 6 are linearly arranged and mounted on the light source mounting portion 7a along the longitudinal direction of the light source mounting portion 7a formed in a strip shape. As described above, the plurality of light sources 6 are arranged so as to face the four end faces 2a and 2b of the light guide plate 2, respectively. The illuminating device 1 of this form is provided with the two board | substrates 7 arrange | positioned along one end surface 2a, and the one board | substrate 7 arrange | positioned along one end surface 2b, for example. Yes. That is, the lighting device 1 includes a total of six substrates 7. Moreover, the illuminating device 1 is provided with the two board | substrates 7 divided | segmented in the left-right direction and arrange | positioned so that the one end surface 2a may be met. A specific configuration of the substrate 7 will be described later. In FIG. 4, only two substrates 7 are shown. In addition, three or more substrates 7 may be disposed on the end surface 2a depending on the length of the end surface 2a or the length of the substrate 7. In addition, two or more substrates 7 may be arranged on the end surface 2b depending on the length of the end surface 2b or the length of the substrate 7.

  The light source holding member 8 is formed by bending a thin metal plate such as an aluminum alloy plate into a predetermined shape. Specifically, the light source holding member 8 includes a base portion 8a disposed so as to face the end surfaces 2a and 2b of the light guide plate 2, and a first extending portion extending from both ends of the base portion 8a in the front-rear direction to the light guide plate 2 side. 8b and the second extending portion 8c, and is formed in an elongated rectangular groove shape as a whole. That is, the light source holding member 8 is formed so that its cross-sectional shape is substantially U-shaped (substantially U-shaped). The first extending portion 8b is connected to the front end of the base portion 8a, and the second extending portion 8c is connected to the rear end of the base portion 8a. The light source holding member 8 of this embodiment is made of an aluminum alloy, and the color of the surface of the light source holding member 8 is silver.

  As described above, the plurality of light sources 6 are arranged so as to face the four end faces 2a and 2b of the light guide plate 2, and the illumination device 1 of this embodiment is arranged along the one end face 2a. 1 light source holding member 8 and one light source holding member 8 arranged along one end surface 2b. That is, the illumination device 1 includes a total of four light source holding members 8 as shown in FIG. The length of the light source holding member 8 arranged along the end surface 2a is longer than the length of the light source holding member 8 arranged along the end surface 2b. A specific configuration of the light source holding member 8 will be described later.

  In FIG. 4, only one light source holding member 8 is shown. Moreover, the number of the light source holding members 8 arranged along each end face 2a, 2b may be plural. In addition, when it is desired to make the length of the light source holding member 8 arranged along the end surface 2a and the length of the light source holding member 8 arranged along the end surface 2b the same length, If the length is “a common length of the light source holding member 8”, the length of the end faces 2 a and 2 b may be an integral multiple of the common length of the light source holding member 8. For example, if the length of the end surface 2b is made equal to the common length of the light source holding member 8 and the length of the end surface 2a is twice the common length of the light source holding member 8, a light source having a common length One holding member 8 can be arranged along the end surface 2b, and two light source holding members 8 having a common length can be arranged along the end surface 2a. Further, if the length of the end surface 2b is twice the common length of the light source holding member 8 and the length of the end surface 2a is three times the common length of the light source holding member 8, the common length The two light source holding members 8 can be arranged in a row along the end surface 2b, and three light source holding members 8 having a common length can be arranged in a row along the end surface 2a.

  As shown in FIG. 6, the light source mounting portion 7a and the light source 6 of the substrate 7 are disposed between the first extending portion 8b and the second extending portion 8c. Moreover, the light source mounting part 7a and the light source 6 are arrange | positioned between the base 8a and the end surfaces 2a and 2b, and are arrange | positioned along the end surfaces 2a and 2b. The light guide plate 2, the reflection sheet 4, and the frame 5 are sandwiched between the first extending portion 8b and the second extending portion 8c. That is, the first extending portion 8b and the second extending portion 8c are disposed so as to sandwich the light guide plate 2 in the front-rear direction.

  The case 9 is formed of a thin metal plate such as a steel plate or an aluminum alloy plate. In this embodiment, the case 9 is formed of an aluminum alloy that has high thermal conductivity and is lightweight. The case 9 is formed by press bending or the like. As shown in FIG. 4, the case 9 includes a bottom surface portion 9 a and a side surface portion 9 b that rises from the outer peripheral end of the bottom surface portion 9 a toward the front side. The case 9 has a flat, rectangular parallelepiped box shape that opens on the front side. Is formed. The side surface portion 9b is formed in a rectangular frame shape, and the shape of the case 9 when viewed from the front-rear direction is a rectangular shape. The case 9 is disposed such that the longitudinal direction of the side surface portion 9b having a rectangular frame shape coincides with the left-right direction.

  On the inner side of the peripheral edge portion 9c of the bottom surface portion 9a, a concave groove portion 9d is formed so as to be recessed from the peripheral edge portion 9c toward the front side. The concave groove 9d is formed in a quadrangular annular shape. The inside of the concave groove portion 9d is a central portion 9e that protrudes toward the rear side. The central portion 9e protrudes rearward from the peripheral edge portion 9c. The thickness of the bottom surface portion 9a is constant. That is, the thickness of the peripheral edge portion 9c, the thickness of the concave groove portion 9d, and the thickness of the central portion 9e are equal. When viewed from the front-rear direction, the area of the central portion 9e is the largest. An attachment hole (not shown) for attaching the lighting device 1 to a wall, a ceiling, or the like is formed in the central portion 9e. In addition, in FIG. 4, illustration of the ditch | groove part 9d and the center part 9e is abbreviate | omitted.

  As described above, the light guide plate 2, the reflection sheet 4, the frame 5, the light source 6, the substrate 7, and the light source holding member 8 are accommodated in the case 9, and the bottom surface of the case 9 (that is, the bottom surface portion 9a). A frame 5 is disposed between the front surface) and the light guide plate 2. The opening on the front end side of the case 9 is closed by the diffusion plate 3. In this embodiment, as shown in FIG. 1 and the like, the outer peripheral surface of the diffusion plate 3 and the outer peripheral surface of the case 9 are arranged on the same surface. However, the outer peripheral surface of the case 9 may be disposed inside the outer peripheral surface of the diffusion plate 3.

(Diffusion plate configuration)
FIG. 7 is a graph showing the angular distribution (A, θ) of scattered light intensity by a single true spherical particle.

  The diffusion plate 3 is disposed on the front side of the light guide plate 2 as described above. That is, the diffusing plate 3 is disposed on the side of the light emitting surface 2 c that constitutes the front surface of the light guide plate 2. The diffusion plate 3 includes a protruding portion 3b that protrudes toward the light guide plate 2 (that is, protrudes rearward). The protrusion 3b is formed along the outer peripheral surface of the diffusing plate 3, and is formed in a rectangular frame shape. The outer peripheral surface of the protrusion 3 b constitutes a part of the outer peripheral surface of the diffusion plate 3. Further, the protruding portion 3b is disposed at a position facing the peripheral edge portion 2d (see FIG. 6) of the light exit surface 2c of the light guide plate 2. The rear surface of the protrusion 3b is formed in a planar shape orthogonal to the front-rear direction, and serves as a light incident surface 3c on which light emitted from the light emission surface 2c is incident. The peripheral edge 2d is a portion of the light exit surface 2c that faces the light incident surface 3c in the front-rear direction, and is formed in a rectangular frame shape.

  The inside of the protrusion 3b is a rectangular recess 3d that is recessed toward the front side, and the diffusion plate 3 has a space surrounded by the protrusion 3b. The bottom surface of the recess 3d is a light incident surface 3e on which light emitted from the light emitting surface 2c is incident. The inner side surface 3f of the protruding portion 3b is formed in a flat shape, and the outer peripheral surface of the diffusion plate 3 and the inner side surface 3f of the protruding portion 3b are parallel to each other. Further, the light incident surfaces 3c and 3e and the outer peripheral surface and the inner side surface 3f of the diffusion plate 3 are orthogonal to each other. The outer peripheral surface of the diffusion plate 3 is a surface in contact with air. Further, the inner side surface 3f of the protruding portion 3b also faces the recess 3d and is a surface in contact with air. Therefore, light that enters the outer peripheral surface of the diffusing plate 3 from the inner side of the protrusion 3 b beyond the critical angle is totally reflected by the outer peripheral surface of the diffusing plate 3. Further, light that enters the inner side surface 3f beyond the critical angle from the inside of the protruding portion 3b is totally reflected by the inner side surface 3f.

  The diffusion plate 3 is made of an acrylic resin or polycarbonate having a high light transmittance. The diffusion plate 3 is a light scattering light guide containing a large number of light scattering particles that are spherical particles. Specifically, the diffusion plate 3 is a light scattering light guide that is given a volumetric uniform scattering ability, and light incident on the diffusion plate 3 is scattered by light scattering particles in the diffusion plate 3. To do. Therefore, in this embodiment, it is possible to make the luminance distribution on the light exit surface 3a uniform. The light scattering particles contained in the diffusion plate 3 are formed of, for example, silicone particles. The light scattering particles are contained in the diffusing plate 3 at a concentration of, for example, an average free path of 0.1 mm or less.

Here, the Mie scattering theory that gives the theoretical basis of the light scattering particles (silicone particles) will be described. Mie scattering theory is a solution to Maxwell's electromagnetic equation for the case where spherical particles (light scattering particles) having a refractive index different from that of a medium (matrix) having a uniform refractive index exist. is there. The intensity distribution I (A, θ) depending on the angle of the scattered light scattered by the light scattering particles is expressed by the following equation (1). A is a size parameter indicating the optical size of the light scattering particle, and is an amount corresponding to the radius r of the spherical particle (light scattering particle) normalized by the wavelength λ of light in the matrix. The angle θ is a scattering angle, and the same direction as the traveling direction of incident light is θ = 0 °.

Further, i ₁ and i ₂ in the formula (1) are represented by the formula (4). And a and b with the subscript “ν” in the expressions (2) to (4) are expressed by the expression (5). P (cos θ) with superscript “1” and subscript “ν” is Legendre's polynomial, and a and b with subscript “ν” are first- and second-order Recatti-Bessel functions Ψ *, ζ * (Where "*" means the subscript "ν") and its derivative. m is the relative refractive index of the light-scattering particles based on the _matrix , and m = n _scatter / n _matrix . Note that m is the relative refractive index of the light scattering particles with reference to the _matrix, and has a relationship of m = n _scatter / n _matrix with the refractive index n _{matrix of the matrix} and the refractive index n _scatter of the light scattering particles.

  FIG. 7 is a graph showing the intensity distribution I (A, θ) of a single true spherical particle based on the above equations (1) to (5). FIG. 7 shows the angular distribution I (A, θ) of the scattered light intensity when there is a true spherical particle as a light scattering particle at the position of the origin O and the incident light is incident from below in FIG. The distance from the origin O to each curve is the scattered light intensity in each scattering angle direction. One curve is scattered light intensity when A is 1.7, another curve is scattered light intensity when A is 11.5, and another curve is scattered light when A is 69.2. It is strength. In FIG. 7, the scattered light intensity is shown on a logarithmic scale. Therefore, in FIG. 7, the portion that appears as a slight difference in intensity is actually a very large difference.

  As shown in FIG. 7, the larger the size parameter A (the larger the particle size of the true spherical particle when considered at a certain wavelength λ), the upper (in front of the irradiation direction) in FIG. It can be seen that the directivity is high and light is scattered. Actually, the angular distribution I (A, θ) of the scattered light intensity is obtained by using the radius r of the scatterer and the relative refractive index m of the medium and the light scattering particles as parameters if the incident light wavelength λ is fixed. Can be controlled.

When light enters such a diffuser plate 3 containing N single spherical particles, the light is scattered by the spherical particles. The scattered light travels through the diffusion plate 3 and is scattered again by other true spherical particles. When true spherical particles are added at a volume concentration of a certain level or more, such scattering is sequentially performed a plurality of times, and then light is emitted from the diffusion plate 3. Such a phenomenon that the scattered light is further scattered is called a multiple scattering phenomenon. In such multiple scattering, analysis by a ray tracing method with a transparent polymer is not easy. However, the behavior of light can be traced by the Monte Carlo method and its characteristics can be analyzed. According to this, when the incident light is non-polarized light, the cumulative distribution function F (θ) of the scattering angle is expressed by the following equation (6).

Here, I (θ) in the equation (6) is the scattering intensity of the true spherical particle having the size parameter A expressed by the equation (1). Assuming that light having an intensity Io is incident on the diffuser plate 3 and transmitted through the distance y, the intensity of the light is attenuated to I due to scattering, and these relationships are expressed by the following equation (7).

Τ in the equation (7) is called turbidity and corresponds to the scattering coefficient of the medium, and is proportional to the number N of particles as in the following equation (8). In the equation (8), σ ^s is a scattering cross section.

From the equation (7), the probability Pt (L) of transmitting through the diffusion plate 3 having the length L without being scattered is expressed by the following equation (9).

Conversely, the probability Ps (L) of scattering up to the optical path length L is expressed by the following equation (10).

  As can be seen from these equations, the degree of multiple scattering in the diffusion plate 3 can be controlled by changing the turbidity τ. By the above relational expression, multiple scattering in the diffusion plate 3 can be controlled using at least one of the size parameter A of the light scattering particles and the turbidity τ as a parameter. The light scattering particles contained in the diffusion plate 3 of this embodiment are, for example, translucent silicone particles having an average particle diameter of 2.4 μm, and turbidity which is a scattering parameter corresponding to the scattering coefficient by the light scattering particles. τ is τ = 0.49 (λ = 550 nm).

(Configuration of substrate, light guide plate and light source holding member)
FIG. 8 is a diagram for explaining the configuration of the light guide plate 2 and the substrate 7 shown in FIG. 4 from the back side. FIG. 9 is an exploded perspective view of a part of the light guide plate 2, the substrate 7, the light source holding member 8 and the like shown in FIG. FIG. 10 is an enlarged view of a portion G in FIG. FIG. 11 is a diagram for explaining the configuration of the HH cross section of FIG. 8. FIG. 12 is a diagram for explaining the configuration of the JJ cross section of FIG. 8.

  As described above, the substrate 7 is a flexible printed circuit board and has a light source mounting portion 7a formed in an elongated strip shape and a circuit connection that is formed in an elongated strip shape and is connected to the light source mounting portion 7a so as to be orthogonal to the light source mounting portion 7a. Part 7b. The circuit connecting portion 7b is connected to the central portion in the longitudinal direction of the light source mounting portion 7a, and the substrate 7 is formed in a T shape. The light source mounting portion 7a is formed with an engaging convex portion 7c that protrudes in a direction perpendicular to the longitudinal direction of the light source mounting portion 7a formed in a strip shape. The engaging convex part 7c is formed so as to slightly protrude toward the rear side, for example. Moreover, the engagement convex part 7c is formed in multiple places in the state which opened the predetermined space | interval in the longitudinal direction of the light source mounting part 7a. In addition, the engaging convex part 7c may be formed so that it may protrude slightly toward the front side. Moreover, the engagement convex part 7c which protrudes slightly toward the back side, and the engagement convex part 7c which protrudes slightly toward the front side may be formed. Moreover, the engaging convex part 7c may protrude in the direction inclined with respect to the direction orthogonal to the longitudinal direction of the light source mounting part 7a. That is, the engagement convex part 7c should just protrude in the direction which cross | intersects the longitudinal direction of the light source mounting part 7a.

  A plurality of light sources 6 are mounted on the light source mounting portion 7a along the longitudinal direction of the light source mounting portion 7a. That is, a plurality of light sources 6 are mounted on the light source mounting portion 7a along the end surfaces 2a and 2b. In the light source mounting portion 7a disposed along the end surface 2a, the plurality of light sources 6 are arranged in a row in the left-right direction. In the light source mounting portion 7a arranged along the end surface 2b, a plurality of light sources 6 are arranged in a line in the vertical direction. In this embodiment, an even number of light sources 6 are mounted on the light source mounting portion 7a. That is, an even number of light sources 6 are arranged along the end faces 2a and 2b. Specifically, as shown in FIG. 9, 18 light sources 6 are mounted on one light source mounting portion 7a. Eighteen light sources 6 are mounted at a constant pitch, and nine light sources 6 are mounted on both sides of the circuit connection portion 7b in the longitudinal direction of the light source mounting portion 7a.

  The light guide plate 2 is made of an acrylic resin having a high light transmittance. The light guide plate 2 is a light scattering light guide containing a large number of light scattering particles in the same manner as the diffusion plate 3, and the light guide plate 2 has light scattering similar to that of the light scattering particles contained in the diffusion plate 3. Contains particles. For example, the diameter of the light scattering particles contained in the light guide plate 2 is 7 μm, and the light scattering particles having a concentration of 0.1 wt% are contained in the light guide plate 2.

  The light guide plate 2 is formed with a plurality of protrusions 2f protruding from the end faces 2a, 2b to the substrate 7 side. That is, the light guide plate 2 is formed with a plurality of protrusions 2 f that protrude from the end surfaces 2 a and 2 b toward the base 8 a of the light source holding member 8. Specifically, the light guide plate 2 is formed with a plurality of protrusions 2f protruding outward in the vertical direction from the end surface 2a and a plurality of protrusions 2f protruding outward in the left-right direction from the end surface 2b. The protrusion 2f is formed in a flat rectangular piece having a longitudinal direction along the end faces 2a and 2b, and the shape of the protrusion 2f when viewed from the front-rear direction is rectangular. . The front end surface of the protrusion 2f protruding from the end surface 2a is formed in a planar shape orthogonal to the up-down direction, and the front end surface of the protrusion 2f protruding from the end surface 2b is formed in a flat shape orthogonal to the left-right direction. In addition, in FIG. 4, illustration of the protrusion part 2f is abbreviate | omitted.

  As shown in FIG. 8, the protrusion 2 f is in contact with the substrate 7. That is, the tip end surface of the protrusion 2f is in contact with the surface of the light source mounting portion 7a on which the light source 6 is mounted. The protrusion 2f is disposed between the light sources 6 arranged in a straight line, and the front end surface of the protrusion 2f is in contact with the portion between the light sources 6 of the light source mounting portion 7a. The plurality of protrusions 2f are formed at a constant pitch, and the protrusions 2f are arranged so as to sandwich three light sources 6 in the longitudinal direction of the light source mounting portion 7a. That is, the light guide plate 2 is formed with a plurality of protrusions 2f at a pitch of three light sources 6 arranged in the longitudinal direction of the light source mounting portion 7a.

  Further, as shown in FIG. 8, one adjacent end portion (specifically, the adjacent end portion of the light source mounting portion 7a) 7d of the two substrates 7 arranged along the end surface 2a is provided. The protrusion 2f is in contact. A part of the light source mounting portion 7a is sandwiched between the base portion 8a of the light source holding member 8 and the protruding portion 2f. That is, the portion between the light sources 6 and the end portion 7d of the light source mounting portion 7a are sandwiched between the base portion 8a and the protruding portion 2f. The substrate 7 is fixed between the light guide plate 2 and the substrate holding member 8 by sandwiching a part of the light source mounting portion 7a between the base portion 8a and the protruding portion 2f.

  A shaft of a screw 20 (to be described later) for fixing the light guide plate 2 and the light source holding member 8 to each other on the portion of the light guide plate 2 where the projection 2f is formed (inside the projection 2f of the light guide plate 2). A plurality of through holes 2g through which the portion 20a is inserted are formed. The through-hole 2g is formed so as to penetrate the light guide plate 2 in the front-rear direction, and is formed at a position on the center line of the protruding portion 2f in the direction along the end surfaces 2a, 2b. Further, the centers of the plurality of through holes 2g formed along the end surface 2a are arranged slightly inward in the vertical direction from the end surface 2a, and the centers of the plurality of through holes 2g formed along the end surface 2b. Is arranged slightly inward in the left-right direction with respect to the end face 2b.

  The through hole 2g is preferably formed on the outer side in the vertical direction or the horizontal direction as much as possible within a range in which the strength of the light guide plate 2 in the portion where the through hole 2g is formed can be ensured. By forming the through hole 2g in this manner, the screw 20 can be disposed at a position that does not easily affect the diffusion of light in the light guide plate 2. That is, it becomes possible to arrange the screw 20 at a position where the luminance unevenness on the light exit surface 3a does not easily occur. Specifically, for example, if the through hole 2g is formed at a position where the inner peripheral surface of the through hole 2g and the end surfaces 2a and 2b coincide with each other, the strength of the light guide plate 2 in the portion where the through hole 2g is formed is ensured. On the other hand, the screw 20 can be disposed at a position in the light guide plate 2 that hardly affects the diffusion of light.

  The “portion of the light guide plate 2 where the protrusion 2f is formed” refers to a portion of the light guide plate 2 near the protrusion 2f. Specifically, it is the portion that is inside the light guide plate 2 within the range of the protrusion 2f itself and the width (longitudinal direction) of the protrusion 2f. Therefore, when at least a part of the through hole 2g is formed in the protrusion 2f, the through hole 2g is formed in a portion of the light guide plate 2 where the protrusion 2f is formed. Further, even if a part of the through hole 2g is out of the range of the width of the protrusion 2f, if the center of the through hole 2g is within the range of the width of the protrusion 2f, the through hole 2g is not connected to the light guide plate 2. This is formed in the portion where the projection 2f is formed.

  As described above, the light source holding member 8 includes the base portion 8a, the first extending portion 8b connected to the front end of the base portion 8a, and the second extending portion 8c connected to the rear end of the base portion 8a. In the light source holding member 8 arranged along the end surface 2a, the vertical width of the second extending portion 8c is constant, and the vertical width of the first extending portion 8b is also constant ( (See FIG. 9). Further, in the light source holding member 8 arranged along the end surface 2b, the width in the left-right direction of the second extension 8c is constant, and the width in the left-right direction of the first extension 8b is also constant. Yes. That is, the first extending portion 8b and the second extending portion 8c are formed in an elongated rectangular flat plate shape.

  Moreover, as shown in FIG. 6 etc., in the light source holding member 8 arranged along the end surface 2a, the vertical width of the second extending portion 8c is larger than the vertical width of the first extending portion 8b. In the light source holding member 8 arranged along the end face 2b, the width of the second extending portion 8c in the left-right direction is wider than the width of the first extending portion 8b in the left-right direction. That is, the width of the second extending portion 8c in the direction from the base portion 8a toward the light guide plate 2 is wider than the width of the first extending portion 8b in this direction. In addition, the width of the second extending portion 8c in this direction is set so that the second extending portion 8c is disposed on the outer peripheral side with respect to the recessed groove portion 9d of the case 9.

  As described above, the light guide plate 2, the reflection sheet 4, and the frame 5 are sandwiched between the first extending portion 8b and the second extending portion 8c. The first extending portion 8 b is connected to the front end of the base portion 8 a and is disposed on the light exit surface 2 c side of the light guide plate 2. Moreover, the 1st extension part 8b is arrange | positioned between the protrusion part 3b of the diffusion plate 3, and the light-guide plate 2, and is contacting the light-incidence surface 3c of the protrusion part 3b. As shown in FIG. 6, the width of the first extending portion 8b in the direction from the base portion 8a toward the light guide plate 2 is narrower than the width of the protruding portion 3b in this direction.

  The first extending portion 8 b performs a light shielding function that prevents the light emitted from the light source 6 from directly entering the diffusion plate 3. In addition, the first extending portion 8b restricts light that enters the protruding portion 3b of the diffusion plate 3 from the peripheral portion 2d of the light emitting surface 2c. A portion of the light incident surface 3c covered by the first extending portion 8b is a shielding region 3g, and a portion of the light incident surface 3c inside the shielding region 3g is an incident region 3h. . In this embodiment, the width of the shielding region 3g and the width of the incident region 3h are set so that the overall brightness of the light exit surface 3a is uniform. For example, the area of the incident area 3h is set to a range of 0.5 to 5 times the area of the shielding area 3g. However, the width of the incident region 3h is preferably set in a range of 1 to 3 times the width of the shielding region 3g. The width of the first extending portion 8b in the direction from the base portion 8a toward the light guide plate 2 is wider than the sum of the protruding amount of the protruding portion 2f from the end surfaces 2a and 2b and the thickness of the substrate 7. That is, the front end of the first extending portion 8b is disposed closer to the center of the light guide plate 2 than the end surfaces 2a and 2b. The width of the second extending portion 8c in the direction from the base portion 8a toward the light guide plate 2 is wider than the width of the protruding portion 3b in this direction.

  The light source holding member 8 is elastically deformed so that a biasing force in a direction in which the first extending portion 8b and the second extending portion 8c approach each other acts. That is, the light source holding member 8 is elastically deformed so that the light guide plate 2, the reflection sheet 4, and the frame 5 sandwiched between the first extending portion 8 b and the second extending portion 8 c are in close contact with each other (first The leading end of the first extending portion 8b and the second extending portion 8c than when the light guide plate 2, the reflection sheet 4, and the frame 5 are not sandwiched between the extending portion 8b and the second extending portion 8c. In a state where it is elastically deformed so that its front end slightly opens in the front-rear direction). The first extending portion 8 b is in contact with the light guide plate 2. The first extending portion 8 b is in close contact with the light guide plate 2. The second extending portion 8 c is in contact with the frame 5. That is, the light source holding member 8 is in contact with the frame 5. Specifically, the front surface of the second extending portion 8 c is in contact with the rear surface of the frame 5. The second extending portion 8 c is in close contact with the frame 5. As described above, the frame 5 is formed of a metal plate having high thermal conductivity. The frame 5 of this embodiment is a heat radiating member arranged between the light guide plate 2 and the second extending portion 8c.

  The light source holding member 8 is formed with a drawing hole 8 e for drawing out the circuit connection portion 7 b of the substrate 7 from the light source holding member 8. As shown in FIG. 10, the lead-out hole 8e is formed at a boundary portion between the base portion 8a and the second extending portion 8c. The lead hole 8e is formed so as to penetrate the rear end portion of the base portion 8a and the base end portion of the second extending portion 8c. The circuit connection portion 7b drawn out from the lead-out hole 8e is routed between the second extending portion 8c and the bottom surface portion 9a of the case 9, and between the frame 5 and the bottom surface portion 9a.

  As shown in FIG. 11, the front end side of the circuit connection portion 7b is electrically connected to the circuit board 14 accommodated in the case 9 (specifically, inside the center portion 9e). Specifically, the front end side of the circuit connection portion 7b is soldered and electrically connected to the front surface of the circuit board 14, and the soldered portion on the front end side of the circuit connection portion 7b is used for sealing. Covered with resin 15. A front end side portion of the sealing resin 15 is disposed in a space 16 formed between the frame portion 5 a and the bracing portion 5 b of the frame 5. The tip end side of the circuit connection portion 7b may be electrically connected to the circuit board 14 via a connector.

  As shown in FIG. 12, an electronic circuit 17 for controlling the light source 6 is mounted on the front surface of the circuit board 14. The electronic circuit 17 is mounted on the circuit board 14 so as to straddle the inner peripheral surface of the frame portion 5a. The electronic circuit 17 is in close contact with the frame portion 5a. Therefore, heat generated in the electronic circuit 17 is transmitted to the frame 5. Therefore, the heat generated in the electronic circuit 17 can be efficiently dissipated using the frame 5 having high thermal conductivity. The circuit board 14 is connected to an external power source by a cable not shown.

  Further, the light source holding member 8 is formed with an engagement hole 8f that engages with the engagement convex portion 7c of the substrate 7. The engagement hole 8f is formed in the second extending portion 8c. The engagement hole 8f is formed so as to penetrate the base end portion of the second extending portion 8c. The second extending portion 8c is formed with a plurality of through holes 8g through which shaft portions 20a of screws 20 described later are inserted. The through hole 8g is formed so as to penetrate the second extending portion 8c. In this embodiment, the first positioning means for positioning the light source holding member 8 with respect to the light guide plate 2 is configured by the through hole 2 g of the light guide plate 2, the through hole 8 g of the light source holding member 8, and the screw 20. Further, a second positioning means for positioning the light source 6 with respect to the light source holding member 8 is configured by the engagement convex portion 7 c of the substrate 7 and the engagement hole 8 f of the light source holding member 8.

(Light guide plate, diffuser plate, frame and light source holding member fixing structure)
13 is a cross-sectional view taken along the line KK of FIG. 14 is a cross-sectional view taken along the line NN in FIG.

  The light guide plate 2, the frame 5, and the light source holding member 8 are fixed to the diffusion plate 3 by screws 20 (see FIGS. 3 and 13). The light source holding member 8 is also fixed to the frame 5 by screws 21 (see FIGS. 3 and 14). The case 9 is fixed to the frame 5 with screws 22 (see FIGS. 3 and 6).

  As described above, the light guide plate 2 has the through hole 2g, and the light source holding member 8 has the through hole 8g. As shown in FIG. 13, the shaft portion 20a of the screw 20 is inserted through the through holes 2g and 8g. A through hole 5c through which the shaft portion 20a of the screw 20 is inserted is also formed in the frame portion 5a of the frame 5. The protrusion 3b of the diffusion plate 3 is formed with a screw hole 3j that engages with a male screw formed on the outer peripheral surface on the distal end side of the shaft portion 20a. A through hole 9g in which the head 20b of the screw 20 is disposed is formed in the peripheral portion 9c of the case 9. The inner diameter of the through hole 9g is larger than the outer diameter of the head 20b.

  The light guide plate 2, the frame 5, and the light source holding member 8 are projected from the rear side of the second extending portion 8c by the screws 20 that are inserted into the through holes 8g, 5c, and 2g and engage with the screw holes 3j. It is fixed to the part 3b. Between the inner peripheral surfaces of the through holes 8g, 5c, and 2g and the outer peripheral surface of the shaft portion 20a, the light guide plate 2, the diffuser plate 3, the frame 5, and the light source holding member 8 that expand and contract with temperature fluctuations are provided. A gap that can absorb the difference in expansion and contraction is formed. The front end (front end) of the shaft portion 20 a is disposed behind the light incident surface 3 e of the diffusion plate 3. The reflective sheet 4 is also formed with a through-hole through which the shaft portion 20a is inserted.

  As shown in FIG. 14, the second extending portion 8c is formed with a through hole 8h through which the shaft portion 21a of the screw 21 is inserted, and the frame portion 5a of the frame 5 is formed on the outer peripheral surface of the shaft portion 21a. A screw hole 5d for engaging the male screw to be engaged is formed. A through hole 9 h in which the head 21 b of the screw 21 is disposed is formed in the peripheral portion 9 c of the case 9. The inner diameter of the through hole 9h is larger than the outer diameter of the head 21b. The light source holding member 8 is fixed to the frame 5 by screws 21 that are inserted into the through holes 8h from the rear side of the second extending portion 8c and engage with the screw holes 5d. A gap is formed between the inner peripheral surface of the through hole 8h and the outer peripheral surface of the shaft portion 21a so as to absorb the difference in expansion / contraction amount between the frame 5 that expands and contracts with temperature fluctuation and the light source holding member 8. Has been. In addition, in the position where the circuit connection part 7b of the board | substrate 7 is drawn, the circuit connection part 7b is also being fixed to the flame | frame 5 with the screw 21, as shown in FIG.

  As shown in FIG. 6, a through-hole 9j through which the shaft portion 22a of the screw 22 is inserted is formed in the concave groove portion 9d of the case 9, and the frame portion 5a of the frame 5 is formed on the outer peripheral surface of the shaft portion 22a. A screw hole 5e is formed in which the male screw to be engaged is engaged. The case 9 is fixed to the frame 5 by screws 22 that are inserted into the through holes 9j from the rear side of the concave groove 9d and engage with the screw holes 5e. A gap is formed between the inner peripheral surface of the through-hole 9j and the outer peripheral surface of the shaft portion 22a so as to absorb the difference in expansion / contraction amount between the frame 5 and the case 9 that expands and contracts with temperature fluctuation. Yes.

  In this embodiment, the light guide plate 2, the frame 5, and the light source holding member 8 are fixed to the protruding portion 3 b of the diffusion plate 3 with screws 20, and the light source holding member 8 is fixed to the frame 5 with screws 21, and then the case 9 is fixed to the frame 5 by screws 22. In addition, the thickness of the bottom surface portion 9a of the case 9 is thicker than the thicknesses of the head portions 20b and 21b of the screws 20 and 21, and the head portions 20b and 21b have a peripheral edge as shown in FIGS. It does not protrude rearward from the rear surface of the portion 9c. In addition, the amount of depression toward the front side of the recessed groove portion 9d with respect to the rear surface of the peripheral portion 9c is equal to or greater than the thickness of the head portion 22b of the screw 22, and as shown in FIG. It does not protrude rearward from the rear surface.

(Light path in the lighting device)
FIG. 15 is a diagram for explaining a light path until the light emitted from the light source 6 is emitted from the light emission surface 3 a of the diffusion plate 3 in the illumination device 1 shown in FIG. 1.

  A part of the light emitted from the light source 6 enters the light guide plate 2 from the end surfaces 2a and 2b of the light guide plate 2, and then, for example, as indicated by a one-dot chain line L1, the light emission surface 2c of the light guide plate 2 and The light travels toward the center of the light guide plate 2 while being totally reflected by the reflection surface 4a of the reflection sheet 4, and proceeds while being scattered by the light scattering particles, and either is emitted from the light exit surface 2c. Further, another part of the light emitted from the light source 6 proceeds while being scattered by the light scattering particles without being totally reflected by the light emitting surface 2c, and is emitted from the light emitting surface 2c. Since the light in the light guide plate 2 is totally reflected by the light emitting surface 2c and the reflecting surface 4a and scattered by the light scattering particles, the luminance of the light emitting surface 2c is in a uniform state.

  A part of the light emitted from the light exit surface 2 c of the light guide plate 2 enters the incident area 3 h of the light incident surface 3 c of the diffusion plate 3. A part of the light incident from the incident region 3h proceeds while being totally reflected by the inner side surface 3f of the projecting portion 3b and the outer peripheral surface of the diffusion plate 3 and scattered by the light scattering particles as indicated by a one-dot chain line L2. The light exits from the area corresponding to the projecting portion 3b (that is, the peripheral edge of the light exit surface 3a). Further, part of the light incident on the light incident surface 3e travels while being scattered by the light scattering particles, and is emitted from the light emitting surface 3a.

(Main effects of this form)
As described above, in this embodiment, the portion of the light incident surface 3c of the diffusing plate 3 that is covered with the first extending portion 8b is the shielding region 3g, and the light emitted from the light source 6 is diffused. It does not enter the plate 3 directly. Therefore, in this embodiment, it is possible to prevent the light source 6 portion from appearing as a point light source on the light exit surface 3a of the diffusion plate 3. Further, the luminance at the peripheral portion of the light exit surface 3a close to the light source 6 tends to be higher than the brightness at the center portion of the light exit surface 3a, but in the present embodiment, the brightness of the first extending portion 8b of the light incident surface 3c is increased. Since the covered portion is the shielding region 3g, the amount of light incident on the peripheral portion (that is, the protruding portion 3b) on the rear surface of the diffuser plate 3 is limited, and the luminance of the peripheral portion of the light exit surface 3a is reduced. It becomes possible to suppress. On the other hand, since the light incident surface 3c is covered by the first extending portion 8b, there is a possibility that a dark portion such as an edge is generated at the peripheral portion of the light emitting surface 3a due to the influence of the first extending portion 8b. However, in this embodiment, the light diffusing plate 3 contains light scattering particles, and light incident on the light diffusing plate 3 is scattered in the light diffusing plate 3, so that the peripheral edge of the light exit surface 3 a is edged. It is possible to prevent the occurrence of such a dark part.

  In addition, the light emitted from the light source 6 is bright near the light source 6 and dark as the distance increases. In this embodiment, the light source 6 faces each of the four end surfaces 2a and 2b of the light guide plate 2. Since it is arranged, the entire light exit surface 3a can be brightened by the light emitted from all the light sources 6. As described above, in this embodiment, it is possible to make the luminance of the light exit surface 3a (the overall brightness of the light exit surface 3a) uniform. That is, in this embodiment, it is possible to equalize the brightness of the light exit surface 3a including the peripheral portion of the light exit surface 3a. In this embodiment, since the light scattered by the light scattering particles is emitted from the light exit surface 3a, the intensity and color tone (wavelength of light) emitted from the light exit surface 3a are the front of the light exit surface 3a. It doesn't change from any direction.

  If the total amount of light incident on the diffusion plate 3 is M, the area of the incident region 3h is S1, and the area of the light incident surface 3e is S2, the amount of light incident on the light incident surface 3c (that is, the incident region) If the amount of light incident on 3h) M1 is M × (S1 / (S1 + S2)), the luminance of the light exit surface 3a can be made more uniform. In addition, since the average human vision is difficult to recognize as a change even if the amount of light changes by about 30%, the amount of light incident on the incident area 3h is 0.7 × M × (S1 / (S1 + S2)) or more. If it is 1.3 × M × (S1 / (S1 + S2)) or less, it is possible to make the brightness of the light exit surface 3a appear uniform to the viewer of the illumination device 1. Further, it is possible to adjust the size of the incident region 3h by adjusting the size of the protruding portion 3b or by adjusting the width of the first extending portion 8b. By adjusting, the incident amount of the light emitted from the light guide plate 2 to the protruding portion 3b can be adjusted, so that the brightness of the light exit surface 3a can be easily equalized.

  In this embodiment, the light source holding member 8 is elastically deformed so that a biasing force in a direction in which the first extending portion 8b and the second extending portion 8c approach each other acts. Therefore, in this embodiment, even before the light source holding member 8 is securely fixed to the diffusion plate 3 or the frame 5 by the screws 20 and 21, the gap between the first extending portion 8b and the second extending portion 8c It is possible to prevent the light source holding member 8 from being displaced with respect to the light guide plate 2, the reflection sheet 4, and the frame 5. Therefore, in this embodiment, the light source holding member 8 can be easily attached. In this embodiment, since the light source holding member 8 is elastically deformed so that the urging force in the direction in which the first extending portion 8b and the second extending portion 8c approach each other acts, the light source holding member 8 is fixed by screws 20 and 21. It is possible to effectively prevent the positional deviation of the light source holding member 8 after being performed.

  In the present embodiment, in the light source holding member 8 disposed along the end surface 2a, the vertical width of the second extending portion 8c is wider than the vertical width of the first extending portion 8b, and the end surface 2b. In the light source holding member 8 arranged along the horizontal axis, the width of the second extending portion 8c in the left-right direction is wider than the width of the first extending portion 8b in the left-right direction. Therefore, in this embodiment, even before the light source holding member 8 is securely fixed to the diffusion plate 3 or the frame 5 with the screws 20 and 21, the light source holding member 8 with respect to the light guide plate 2, the reflection sheet 4, and the frame 5. It is possible to effectively prevent the positional deviation, and more effectively prevent the positional deviation of the light source holding member 8 after being fixed by the screws 20 and 21.

  In this embodiment, the width of the second extending portion 8c is wide. Therefore, in this embodiment, the through hole 8g through which the shaft portion 20a of the screw 20 is inserted can be formed at a relatively free position. In this embodiment, the light guide plate 2 is formed with a plurality of protrusions 2 f that protrude from the end surfaces 2 a and 2 b of the light guide plate 2 toward the substrate 7 and come into contact with the substrate 7. A through hole 2g through which the shaft portion 20a of the screw 20 is inserted is formed in the formed portion. Therefore, in this embodiment, the screw 20 can be disposed at a position closer to the end faces 2a and 2b of the light guide plate 2. That is, in this embodiment, the screw 20 can be disposed at a position in the light guide plate 2 where it is difficult to affect the diffusion of light, and at the position where the luminance unevenness of the light exit surface 3a does not easily occur (in the luminance distribution). The screw 20 can be disposed at a position where it is difficult to influence. In this embodiment, the light guide plate 2, the frame 5, and the light source are inserted by screws 20 that are inserted into the through holes 8 g, 5 c, and 2 g from the rear side of the second extending portion 8 c and engage with the screw holes 3 j of the protruding portion 3 b. The holding member 8 is fixed to the protruding portion 3b, and a screw 20 is disposed on the rear side of the thick protruding portion 3b. For this reason, in this embodiment, the screw 20 becomes inconspicuous when viewing the light exit surface 3a.

  In this embodiment, the light guide plate 2 is formed with a plurality of protrusions 2 f that protrude from the end surfaces 2 a and 2 b of the light guide plate 2 toward the substrate 7 and come into contact with the substrate 7. Therefore, in this embodiment, it is possible to maintain a gap according to the protruding amount of the protruding portion 2f from the end surfaces 2a and 2b between the light source 6 mounted on the substrate 7 and the end surfaces 2a and 2b. Therefore, in this embodiment, the gap between the end surfaces 2a and 2b and the light source 6 can be accurately maintained. As a result, in this embodiment, it is possible to prevent the light guide plate 2 from being thermally deformed due to the heat generated by the light source 6. In addition, it is possible to suppress variation in distance between each of the plurality of light sources 6 and the end surfaces 2a and 2b, and as a result, it is possible to suppress luminance unevenness on the light exit surface 3a.

  In particular, in this embodiment, the number of the light sources 6 arranged along one end face 2a, 2b is an even number, and the protrusions 2f are arranged at equal intervals between the light sources 6, so that a plurality of light sources 6 and the end faces 2a, 2b can be effectively suppressed from being dispersed. Therefore, in this embodiment, it is possible to effectively suppress the luminance unevenness on the light exit surface 3a. In this embodiment, a through hole 2g through which the shaft portion 20a of the screw 20 is inserted is formed in a portion of the light guide plate 2 where the protrusion 2f is formed. Since the screw 20 is disposed between the light sources 6 and the screw 20 can be disposed at a position closer to the end surfaces 2a and 2b of the light guide plate 2 as described above, The light emitted from the light source 6 is not easily blocked by the screw 20. Therefore, in this embodiment, it is possible to suppress the luminance unevenness of the light exit surface 3a caused by the screw 20.

  In this embodiment, the projecting portion 2 f is disposed between the light sources 6 arranged in a straight line, and the tip end surface of the projecting portion 2 f is in contact with a portion of the substrate 7 between the light sources 6. Therefore, in this embodiment, for example, the lighting device 1 can be downsized (thinned) in the front-rear direction compared to the case where the protrusion 2f is arranged so as to overlap the light source 6 in the front-rear direction. . Further, in this embodiment, the light source holding member 8 includes a base portion 8a disposed so as to face the end faces 2a and 2b of the light guide plate 2, and a portion between the light source 6 and an end portion of the light source mounting portion 7a. Since 7d is sandwiched between the base 8a and the projection 2f, the base 8a and the projection 2f can prevent the substrate 7 from wobbling (moving or shaking). In particular, in this embodiment, since the substrate 7 is a flexible flexible printed substrate, the substrate 7 is likely to wobble, but the substrate 7 is a flexible flexible printed substrate by sandwiching the substrate 7 between the base portion 8a and the protruding portion 2f. It is possible to prevent wobbling. In this embodiment, one protrusion 2f is in contact with the adjacent end 7d of the two substrates 7 arranged along the end surface 2a, and one end of the two substrates 7 is one. It is pressed by the projection 2f. Therefore, in this embodiment, it is possible to reduce the number of protrusions 2f formed on the light guide plate 2, and as a result, the configuration of the light guide plate 2 can be simplified.

  In this embodiment, the substrate 7 includes a strip-shaped light source mounting portion 7a and a strip-shaped circuit connection portion 7b connected to the light source mounting portion 7a so as to be orthogonal to the light source mounting portion 7a. A lead-out hole 8e for pulling out the circuit connection portion 7b from the member 8 is formed. Therefore, in this embodiment, the circuit connecting portion 7b is connected to the left end or the right end of the light source mounting portion 7a arranged along the end surface 2a and the upper end or the lower end of the light source mounting portion 7a arranged along the end surface 2b. In comparison with the case where the circuit connection portion 7b is pulled out from the longitudinal end portion of the light source holding member 8 formed in a square groove shape, the lighting device 1 can be downsized in the left-right direction and the up-down direction. Become. Further, in the present embodiment, since the circuit connection portion 7 b is drawn out from the drawing hole 8 e formed in the light source holding member 8, the substrate 7 can be positioned with respect to the light source holding member 8. Furthermore, in this embodiment, since the circuit connection portion 7b connected to the light source mounting portion 7a is drawn out from the extraction hole 8e so as to be orthogonal to the light source mounting portion 7a, the two substrates 7 are arranged along the end surface 2a. Even if they are arranged, it is possible to prevent the substrates 7 from overlapping each other. Therefore, in this embodiment, even if the two substrates 7 are arranged in a line, the substrate 7 can be easily routed.

  In this embodiment, a lead-out hole 8e is formed at the boundary portion between the base portion 8a of the light source holding member 8 and the second extending portion 8c. Therefore, in this embodiment, the circuit connection portion 7b can be easily routed toward the rear surface side of the light guide plate 2 so that the light emission surface 2c of the light guide plate 2 is not covered by the circuit connection portion 7b. In the present embodiment, the lead-out hole 8e is formed so as to penetrate the rear end portion of the base portion 8a, and is also formed so as to penetrate the base end portion of the second extending portion 8c. Therefore, the circuit connection portion 7 b can be pulled out to the rear surface side of the frame 5 without drawing the circuit connection portion 7 b between the base portion 8 a and the side surface portion 9 b of the case 9. Therefore, in this embodiment, the lighting device 1 can be downsized in the left-right direction and the up-down direction. Further, the circuit connection portion 7b can be pulled out to the rear surface side of the frame 5 without drawing the circuit connection portion 7b between the base portion 8a and the side surface portion 9b. It becomes possible to approach. Therefore, when the outer peripheral surface of the diffusing plate 3 and the outer surface of the side surface portion 9b (that is, the outer peripheral surface of the case 9) are arranged on the same plane, the outer peripheral surface of the diffusing plate 3 may be brought closer to the light source 6. As a result, it is possible to prevent a decrease in luminance around the light exit surface 3a of the diffusion plate 3.

  In this embodiment, the circuit connection portion 7b is connected to the central portion of the light source mounting portion 7a. Therefore, in this embodiment, it becomes possible to hold the light source mounting portion 7a in a balanced manner on the light source holding member 8. Further, in this embodiment, the engaging convex portion 7c protruding rearward is formed in the light source mounting portion 7a, and the engaging hole 8f with which the engaging convex portion 7c is engaged is formed in the light source holding member 8. Therefore, in this embodiment, the substrate 7 can be more reliably positioned with respect to the light source holding member 8, and the wobbling of the substrate 7 with respect to the light source holding member 8 can be suppressed when the lighting device 1 is assembled. It becomes possible.

  In this embodiment, the color of the surface of the light source holding member 8 is silver. Therefore, even if the color of the light emitted from the light source 6 is white, it is easy to suppress the discoloration of the light on the light emitting surface 3a due to the color of the surface of the light source holding member 8. In this embodiment, the light source holding member 8 is made of an aluminum alloy, and it is not necessary to color the surface of the light source holding member 8 in silver. Therefore, in this embodiment, the manufacturing cost of the light source holding member 8 can be reduced. Moreover, in this embodiment, since the light source holding member 8 is formed of an aluminum alloy, the light source holding member 8 can be reduced in weight. Moreover, since the thermal conductivity of the aluminum alloy is high, in this embodiment, the heat generated by the light source 6 can be efficiently dissipated from the light source holding member 8 that holds the light source 6 and is generated by the light source 6. Heat can be efficiently transferred to the frame 5.

  In this embodiment, a reinforcing frame 5 is disposed on the rear side of the reflection sheet 4. Therefore, in this embodiment, it is possible to ensure the rigidity of the lighting device 1 even if the area of the light exit surface 3a is increased. Therefore, for example, it is possible to suppress the amount of bending of the left end side of the lighting device 1 with respect to the right end side of the lighting device 1, and as a result, suppress the luminance unevenness of the light emitting surface 3 a caused by the bending of the lighting device 1. It becomes possible.

  In this embodiment, the frame 5 includes a flat frame portion 5a formed in a rectangular frame shape, and a flat bracing portion 5b formed in an X shape and connecting diagonals of the frame portion 5a. Therefore, it is possible to reduce the weight of the lighting device 1 as compared with the case where the frame 5 is formed in a rectangular flat plate shape. Further, according to the study of the present inventor, when the area of the frame 5 when viewed from the front-rear direction is constant, the braces that connect the diagonals of the frame portion 5a and the frame portion 5a formed in a rectangular frame shape. When the frame 5 is configured by the portion 5b, the rigidity of the frame 5 can be effectively increased, and the bending of the lighting device 1 can be effectively suppressed. Therefore, in this embodiment, it is possible to effectively suppress the luminance unevenness of the light exit surface 3a caused by the bending of the lighting device 1.

  In this embodiment, the front surface of the second extending portion 8c of the light source holding member 8 is in contact with the rear surface of the frame 5 formed of a metal plate having high thermal conductivity. Therefore, in this embodiment, it is possible to transfer the heat generated by the light source 6 to the frame 5 via the second extending portion 8c. Further, in this embodiment, as shown in FIG. 6 and the like, the rear surface of the frame 5 is in contact with the front surface of the concave groove portion 9d of the case 9, so that the heat transmitted to the frame 5 can be transmitted to the case 9. It becomes possible. Therefore, in this embodiment, it is possible to efficiently dissipate heat generated by the light source 6. Moreover, in this embodiment, since the concave groove portion 9d is formed in the case 9, the rigidity of the case 9 can be increased. The concave groove portion 9d of this embodiment has both a function of efficiently dissipating heat generated by the light source 6 and a function of increasing the rigidity of the case 9.

  In this embodiment, since the plurality of light sources 6 are arranged so as to face the four end faces 2 a and 2 b of the light guide plate 2, the light source 6 transmitted to the frame 5 through the light source holding member 8. Although heat tends to concentrate on the diagonal part of the frame part 5a, in this embodiment, since the bracing part 5b that connects the diagonals of the frame part 5a is formed in the frame 5, the bracing part 5b is used. Thus, it is possible to efficiently dissipate the heat concentrated on the diagonal portion of the frame portion 5a. Further, since the bracing portion 5b is disposed at a position farther from the light source 6 than the frame portion 5a, the temperature is lower than that of the frame portion 5a, and a thermal gradient is generated inside the frame 5. Therefore, in this embodiment, heat conduction to the frame 5 is promoted, and the heat of the light source 6 can be dissipated more efficiently.

(Modification 1 of diffusion plate)
FIG. 16 is a diagram for explaining a configuration of a protruding portion 3b according to another embodiment of the present invention. In FIG. 16, a part of the protrusion 3b and its peripheral part are shown from the rear side.

  In the embodiment described above, the inner side surface 3f of the protruding portion 3b may be formed such that the shape when viewed from the front-rear direction is a wavy uneven shape. The unevenness of the inner side surface 3f is formed along the longitudinal direction of the substrate mounting portion 7a (that is, the arrangement direction of the plurality of light sources 6). In this case, the light incident on the incident region 3h is easily diffused by the inner side surface 3f and reflected in the protruding portion 3b as shown by the arrow in FIG. For this reason, it is possible to effectively suppress the peripheral edge portion of the light exit surface 3a from becoming brighter and dark as if the peripheral edge portion of the light reflecting surface 3a was trimmed. Therefore, it is possible to further uniform the overall brightness of the light exit surface 3a. In FIG. 16, for convenience of explanation, the unevenness of the inner side surface 3f is exaggerated. Further, the pitch of the unevenness and the depth (or height) of the unevenness of the inner surface 3f with respect to the arrangement pitch of the light sources 6 can be arbitrarily set.

(Modification 2 of diffusion plate)
FIG. 17 is a diagram for explaining a configuration of a protruding portion 3b according to another embodiment of the present invention. 17A shows a part of the protrusion 3b and its peripheral part from the rear side, and FIG. 17B shows a part of the protrusion 3b and its peripheral part on one side in the left-right direction (or one in the vertical direction). Side).

  In the embodiment described above, a plurality of V-shaped grooves 3k may be formed in the light incident surface 3c of the protrusion 3b. The groove 3k is formed in the light incident surface 3c so as to cross the light incident surface 3c between the outer peripheral surface of the diffusion plate 3 and the inner side surface 3f. The groove 3k has a light prism effect, and a part of the light incident from the incident region 3h is diffused on the slope of the groove 3k as shown by the arrow in FIG. Is incident on. For this reason, in this case, it is possible to effectively suppress the peripheral edge of the light exit surface 3a from becoming brighter and dark as if the peripheral edge of the light reflecting surface 3a was trimmed. Therefore, it is possible to further uniform the overall brightness of the light exit surface 3a.

  16 may be formed on the inner side surface 3f of the protruding portion 3b, and the groove 3k shown in FIG. 17 may be formed on the light incident surface 3c of the protruding portion 3b. In FIG. 17, the groove 3k is exaggerated for convenience. The groove 3k only needs to have a light prism effect, and the relative position of the groove 3k with respect to the light source 6, the depth of the groove 3k, and the pitch of the grooves 3k can be arbitrarily set. Furthermore, a so-called prism sheet may be used as the groove 3k. Further, the groove 3k may be formed only in the incident region 3h. Further, the groove 3k may be formed along the inner side surface 3f (that is, in the longitudinal direction of the substrate mounting portion 7a).

(Modification 1 of light guide plate)
FIG. 18 is a diagram for explaining the configuration of a light guide plate 2 according to another embodiment of the present invention. In FIG. 18, a part of the peripheral edge 2d of the light exit surface 2c of the light guide plate 2 and its peripheral part are shown from the front side.

  In the embodiment described above, the diffusion surface 2j may be formed on the peripheral edge 2d of the light exit surface 2c. The diffusing surface 2j is formed by performing a roughening process on a predetermined position of the peripheral edge 2d, and is, for example, a fine dot-like uneven surface. As shown in FIG. 18, the diffusing surface 2j is disposed between the adjacent light sources 6. The shape of the diffusing surface 2j when viewed from the front-rear direction is a triangle with the bases on the side of the end surfaces 2a and 2b.

  In the light guide plate 2 on which the diffusing surface 2j is not formed, the vicinity of the light emission direction of the light source 6 is bright, and the peripheral portion (for example, the region between the adjacent light sources 6) that is shifted from the light emission direction is dark. If the diffusion surface 2j is formed in the dark peripheral part, the light is diffused in the peripheral part and the peripheral part becomes bright. Therefore, it is possible to suppress the luminance unevenness of the peripheral portion 2d, and the synergistic effect with the provision of the protruding portion 3b does not darken the peripheral portion of the light exit surface 3a as if it is edged, It becomes possible to further equalize the overall brightness of the light exit surface 3a including the peripheral portion.

  Note that the shape of the diffusing surface 2j when viewed from the front-rear direction may be a shape other than a triangle with the end surfaces 2a and 2b as the base. However, the light emitted from the light source 6 becomes darker as the distance from the light source 6 increases, and the difference in brightness from the surroundings decreases as the distance from the light source 6 increases. Therefore, in order to make the overall brightness of the light exit surface 3a more uniform, the area of the diffusion surface 2j when viewed from the front-rear direction is gradually reduced as the distance from the light source 6 increases. preferable.

(Modification 2 of the light guide plate)
FIG. 19 is a diagram for explaining the configuration of a light guide plate 2 according to another embodiment of the present invention. In FIG. 19, a part of the peripheral edge 2d of the light exit surface 2c of the light guide plate 2 and its peripheral part are shown from the front side.

  In the modification shown in FIG. 18, the diffusing surface 2j is a fine uneven surface formed by performing a roughening process on a predetermined position of the peripheral edge 2d, but the diffusing surface 2j includes a plurality of fine lenses. You may be comprised by the convex part 2h of a shape. In this modified example, each dot shown in FIG. 19 is a fine convex portion 2h having a convex lens shape. On the diffusing surface 2j, the aggregate of the convex portions 2h is arranged so as to become denser as it approaches the intermediate position between the adjacent light sources 6 and as it approaches the end surfaces 2a and 2b. That is, the aggregate of the convex portions 2h is arranged so as to become rougher as it gets away from the intermediate position between the adjacent light sources 6 and away from the end faces 2a and 2b.

  Also in this modified example, light is diffused in the portion between the light sources 6 that tends to be dark, and this portion also becomes bright. Therefore, it is possible to suppress the luminance unevenness of the peripheral portion 2d, and the synergistic effect with the provision of the protruding portion 3b does not darken the peripheral portion of the light exit surface 3a as if it is edged, It becomes possible to further equalize the overall brightness of the light exit surface 3a including the peripheral portion. In addition, as shown in FIG. 19, you may make the convex part 2h interspersed in the center part (part in which the diffusion surface 2j is not formed) of the light-projection surface 2c of the light-guide plate 2. As shown in FIG. In this case, it is possible to suppress color spots of the lighting device 1. Moreover, the number of the convex parts 2h arrange | positioned between the adjacent light sources 6 may be one. Further, the diffusing surface 2j may be constituted by a plurality of fine lens-shaped concave portions, or may be constituted by a plurality of fine truncated cone-shaped irregularities. Further, the diffusing surface 2j may be constituted by a plurality of V-shaped grooves. In this case, the diffusing surface 2j has a prism effect. In this case, the plurality of grooves are formed so as to spread radially from the intermediate positions of the adjacent light sources 6 on the end faces 2a and 2b toward the inside of the diffusion plate 2, for example.

(Other variations of light guide plate)
In the embodiment described above, the through hole 2g of the light guide plate 2 is formed in the portion of the light guide plate 2 where the protrusion 2f is formed, but the through hole 2g is formed of the protrusion 2f of the light guide plate 2. It may be formed at a position deviated from the portion where it is formed. In the above-described embodiment, one protrusion 2f is in contact with the adjacent end 7d of the two substrates 7 arranged along the end surface 2a, but is arranged along the end surface 2a. The protrusions 2 f may be formed on the light guide plate 2 so that one protrusion 2 f abuts on each of the adjacent end portions 7 d of the two substrates 7. Furthermore, in the embodiment described above, the tip surface of the protrusion 2f is in contact with the portion between the light sources 6 of the light source mounting portion 7a, but the tip surface of the protrusion 2f is the front-rear direction of the light source mounting portion 7a. May be in contact with a portion shifted from the mounting position of the light source 6 (that is, a front side portion or a rear side portion of the mounting position of the light source 6).

  In the embodiment described above, the tip surface of the protrusion 2 f is in contact with the substrate 7, but the tip surface of the protrusion 2 f may be in contact with the light source holding member 8. Specifically, the front end surface of the protrusion 2f may abut on the base 8a. Since the board | substrate 7 is hold | maintained in the state positioned by the light source holding member 8, and the light source 6 is hold | maintained at the light source holding member 8 via the board | substrate 7, even in this case, it is with the form mentioned above. Similarly, a gap corresponding to the amount of protrusion of the protrusion 2f from the end surfaces 2a and 2b can be maintained between the light source 6 mounted on the substrate 7 and the end surfaces 2a and 2b. Therefore, the gap between the end surfaces 2a and 2b and the light source 6 can be accurately maintained. In this case, it is preferable that the substrate 7 is securely fixed to the base portion 8a of the light source holding member 8 with a double-sided tape, an adhesive, or the like.

(Modification of light guide plate and diffuser plate)
In the embodiment described above, the diffusion plate 3 shown in FIG. 16 and the light guide plate 2 shown in FIG. 18 may be used in combination, or the diffusion plate 3 shown in FIG. 16 and the light guide plate 2 shown in FIG. May be used. Moreover, in the form mentioned above, the diffusion plate 3 shown in FIG. 17 and the light guide plate 2 shown in FIG. 18 may be used in combination, or the diffusion plate 3 shown in FIG. 17 and the light guide plate 2 shown in FIG. May be used in combination. Further, in the embodiment described above, the diffusing plate 3 in which the unevenness shown in FIG. 16 is formed on the inner side surface 3f of the protrusion 3b and the groove 3k shown in FIG. 17 is formed in the light incident surface 3c of the protrusion 3b is shown in FIG. 16 may be used in combination with the light guide plate 2 shown in FIG. 16, and the unevenness shown in FIG. 16 is formed on the inner side surface 3f of the protrusion 3b, and the groove 3k shown in FIG. 17 is formed on the light incident surface 3c of the protrusion 3b. The diffusing plate 3 formed with the light guide plate 2 shown in FIG. 19 may be used in combination. In these cases, it is possible to further equalize the overall brightness of the light exit surface 3a including the peripheral portion.

(Modified frame)
FIG. 20 is a front view of a frame 5 according to another embodiment of the present invention. In the embodiment described above, the frame 5 includes a frame portion 5a formed in a rectangular frame shape and a bracing portion 5b formed in an X shape and connecting diagonals of the frame portion 5a. In addition to this, for example, as shown in FIG. 20A, a frame portion 5a is formed by two long side portions 5g parallel to each other and two short side portions 5h parallel to each other. In addition, the frame 5 may include a frame portion 5a and a connecting portion 5j formed in a cross shape and connecting the centers of the long side portions 5g and connecting the centers of the short side portions 5h.

  Further, as shown in FIG. 20B, the frame 5 may be composed of a frame portion 5a and a connecting portion 5k that is formed in a straight line and connects the centers of the short side portions 5h. As shown to C), you may be comprised from the frame part 5a and the connection part 5n which is formed in linear form and connects the centers of the long side part 5g. Furthermore, as shown in FIG. 20 (D), the frame 5 may be composed of a frame portion 5a and a connecting portion 5p that is formed in a lattice shape and connects the long side portions 5g and the short side portions 5h. good. Moreover, the frame 5 may be comprised from any one of the connection part 5j, the connection part 5k, the connection part 5n, or the connection part 5p, the frame part 5a, and the bracing part 5b. Moreover, the frame 5 may be comprised only by the frame part 5a, and may be formed in the rectangular flat form.

  Moreover, in the form mentioned above, although the flame | frame 5 is formed with the aluminum alloy, the flame | frame 5 may be formed with a metal plate with high heat conductivity other than an aluminum alloy. The frame 5 may be formed of a material having low thermal conductivity other than the metal plate.

(Substrate variations)
In the embodiment described above, the circuit connection portion 7b is connected to the center of the light source mounting portion 7a, but the circuit connection portion 7b may be connected to a position shifted from the center of the light source mounting portion 7a. In the above-described embodiment, the engaging convex portion 7c is formed on the light source mounting portion 7a. However, the engaging convex portion 7c may not be formed on the light source mounting portion 7a. In this case, it is not necessary to form the engagement hole 8f in the light source holding member 8. Further, in the above-described form, the circuit connection portion 7b is connected to the light source mounting portion 7a so as to be orthogonal to the light source mounting portion 7a. However, the circuit connection portion 7b is one end of the light source mounting portion 7a formed in a strip shape or It may be connected to the other end. In this case, the circuit connection portion 7b is pulled out from the end portion in the longitudinal direction of the light source holding member 8 formed in a square groove shape. In this case, it is not necessary to form the extraction hole 8e in the light source holding member 8. Moreover, although the board | substrate 7 is a flexible printed circuit board with the form mentioned above, the board | substrate 7 may be rigid boards, such as a glass epoxy board | substrate. In this case, for example, the board 7 and the circuit board 14 are electrically connected via a flexible printed board, lead wires, or the like.

  In the embodiment described above, the circuit connection portion 7b is connected to the light source mounting portion 7a so as to be orthogonal to the light source mounting portion 7a. However, the circuit connection portion 7b has a direction orthogonal to the longitudinal direction of the light source mounting portion 7a and the light source mounting. You may connect with the light source mounting part 7a so that it may incline with respect to the longitudinal direction of the part 7a. That is, the circuit connection part 7b should just be connected with the light source mounting part 7a so that it may cross | intersect the light source mounting part 7a. If the circuit connection portion 7b is connected to the light source mounting portion 7a so as to intersect the light source mounting portion 7a, the same effect as the above-described embodiment can be obtained. That is, in this case, the circuit connection portion 7b is connected to the left end or the right end of the light source mounting portion 7a arranged along the end surface 2a and the upper end or the lower end of the light source mounting portion 7a arranged along the end surface 2b. Compared with the case where the circuit connection portion 7b is pulled out from the end portion in the longitudinal direction of the light source holding member 8 formed in a square groove shape, the lighting device 1 can be downsized in the left-right direction and the up-down direction. . Even in this case, the circuit connection portion 7 b can be pulled out from the drawing hole 8 e formed in the light source holding member 8, so that the substrate 7 can be positioned with respect to the light source holding member 8. Further, in this case, since the circuit connection portion 7b connected to the light source mounting portion 7a is drawn out from the extraction hole 8e so as to intersect the light source mounting portion 7a, the two substrates 7 are arranged along the end surface 2a. Even if it arrange | positions by, it becomes possible to prevent the board | substrates 7 from overlapping.

(Modification 1 of light source holding member)
FIG. 21 is a view for explaining the configuration of a light source holding member 8 according to another embodiment of the present invention. In the embodiment described above, the first extending portion 8b of the light source holding member 8 is formed in an elongated rectangular shape having a constant width over the entire length of the first extending portion 8b. In addition, for example, as shown in FIG. 21, a plurality of recesses 8j that are recessed from the tip of the first extending portion 8b toward the base portion 8a may be formed in the first extending portion 8b. The plurality of recesses 8j are formed at regular intervals along the longitudinal direction of the light source mounting portion 7a of the substrate 7. The convex portion 8k formed between the concave portions 8j covers the front side of the light source 6, and the concave portion 8j is opened between the adjacent light sources 6. The light emitted from the light source 6 is shielded by the convex portion 8k so as not to be directly incident on the protruding portion 3b, and enters the protruding portion 3b from the concave portion 8j around the convex portion 8k.

  In this modification, compared to the case where the first extending portion 8b is formed in an elongated rectangular shape, the brightness of light incident on the protruding portion 3b between the light sources 6 at a position close to the light source 6, and the light source It is possible to reduce the difference from the brightness of the light incident on the protrusion 3b at a position away from 6. Therefore, it becomes possible to further equalize the brightness of the entire surface of the light exit surface 3a. If the difference in the brightness of light incident on the protrusion 3b between the light sources 6 can be reduced, the shape of the convex portion 8k may be a trapezoidal shape or a triangle with a thin tip. The tip of the convex portion 8k may be circular.

(Modification 2 of light source holding member)
22 and 23 are views for explaining the configuration of a light source holding member 8 according to another embodiment of the present invention. In the embodiment described above, the second extending portion 8c of the light source holding member 8 is formed in an elongated rectangular shape having a constant width over the entire length of the second extending portion 8c. In addition, for example, as shown in FIG. 22, a plurality of recesses 8n that are recessed from the tip of the second extending portion 8c toward the base portion 8a may be formed in the second extending portion 8c. The plurality of recesses 8n are formed at regular intervals along the longitudinal direction of the light source mounting portion 7a of the substrate 7. In addition, the recess 8n is formed between the adjacent through hole 8g and the through hole 8g and between the adjacent through hole 8g and the through hole 8f in the longitudinal direction of the light source mounting portion 7a. A through hole 8g or a through hole 8f is formed in the convex portion 8p formed between the two. In this modification, as shown in FIG. 22, the width of the portion of the second extending portion 8c where the convex portion 8p is formed is wider than the width of the first extending portion 8b. That is, a part of the second extending portion 8c is wider than the first extending portion 8b. In the embodiment described above, the width of the second extending portion 8c is wider than the width of the first extending portion 8b, but the width of the second extending portion 8c is the same as that of the first extending portion 8b. It may be less than the width.

  Further, in the above-described form, the extraction hole 8e for drawing out the circuit connection portion 7b of the substrate 7 from the light source holding member 8 is formed at the boundary portion between the base portion 8a and the second extension portion 8c, but the extraction hole 8e. May be formed only in the base portion 8a, or may be formed only in the second extending portion 8c. That is, the lead-out hole 8e may be formed so as not to penetrate the second extending portion 8c, or may be formed so as not to penetrate the base portion 8a similarly to the engaging hole 8f. However, if the extraction hole 8e is formed so as to penetrate the base 8a and the second extension 8c at the boundary between the base 8a and the second extension 8c, the circuit connection portion 7b is provided in the extraction hole 8e. It becomes easy to pass, and the assembly work of the illuminating device 1 becomes easy.

  In the above-described embodiment, the light source holding member 8 has the extraction hole 8e. However, as shown in FIG. 23, the light source holding member 8 has a notch 8r for pulling out the circuit connection portion 7b from the light source holding member 8. 8 may be formed. In this case, the cutout portion 8r is formed so as to be cut out from the distal end of the second extending portion 8c toward the base portion 8a. However, in consideration of the rigidity of the light source holding member 8, it is preferable that the extraction hole 8e is formed in the light source holding member 8 as described above. In the above-described embodiment, the engagement hole 8f is formed so as to penetrate the base end portion of the second extending portion 8c. However, the engagement hole 8f is formed at the rear of the base portion 8a in the same manner as the extraction hole 8e. You may form so that an edge part and the base end part of the 2nd extension part 8c may be penetrated. However, when the engagement hole 8f is formed so as not to penetrate the rear end portion of the base portion 8a as in the above-described form, the engagement hole 8f is formed so as to penetrate the rear end portion of the base portion 8a. Compared with the case where it is made, it becomes possible to position the engaging convex part 7c reliably.

  In the embodiment described above, the light source holding member 8 is made of an aluminum alloy, and the surface of the light source holding member 8 is silver, but the light source is held so that the surface of the light source holding member 8 is silver. The surface of the member 8 may be plated or the surface of the light source holding member 8 may be colored. Moreover, in the form mentioned above, although the light source holding member 8 is formed with the aluminum alloy, the light source holding member 8 may be formed with stainless steel. Also in this case, it is not necessary to color the surface of the light source holding member 8 in silver. Further, the color of the surface of the light source holding member 8 may be a color other than silver. For example, the light source holding member 8 may be made of a copper alloy, and the color of the surface of the light source holding member 8 may be copper. However, if the color of the light emitted from the light source 6 is white and the color of the surface of the light source holding member 8 is copper, the surface of the light emitting surface 3a is caused by the color of the surface of the light source holding member 8. There is a risk that the color of the light will turn yellowish. If the light source holding member 8 is made of a copper alloy, it is possible to improve the heat dissipation of the light source 6 and the thermal conductivity to the frame 5.

(Variation 1 of light source arrangement position)
FIG. 24A is a graph for explaining the distribution of the brightness of the light exit surface 3a of the illumination device 1 according to another embodiment of the present invention, and FIG. It is a graph for demonstrating distribution of the brightness of the light-projection surface 3a when using the two illuminating devices 1 concerning this embodiment in combination.

  In the embodiment described above, the light source 6 is disposed so as to face the four end faces 2a, 2b of the light guide plate 2, but the light source 6 may be disposed so as to face only the two end faces 2b. In this case, since light leaks from the end surface 2a where the light source 6 is not disposed, the brightness of the peripheral portion of the light exit surface 3a close to the end surface 2a is darker than the brightness of the central portion of the light exit surface 3a. That is, the brightness distribution of the single light exit surface 3a of the lighting device 1 is as shown in FIG. In addition, the both ends of the graph of FIG. 24 (A) have shown the brightness of the peripheral part of the light-projection surface 3a near the end surface 2a. In addition, a two-dot chain line in FIG. 24A schematically shows light leakage from the end surface 2a.

  On the other hand, as shown in FIG. 2 (A), when the two lighting devices 1 are combined so that the end faces 2a are adjacent to each other, as shown by the arrows in FIG. Light leaking from one end face 2a of the end faces 2a is incident on the other end face 2a, and light leaking from the other end face 2a is incident on one end face 2a. Therefore, even when the light source 6 is arranged so as to face only the end surface 2b, the two lighting devices 1 can be joined together by combining the two lighting devices 1 so that the end surfaces 2a are adjacent to each other. The brightness of the light exit surface 3a can be equalized without reducing the brightness of the light exit surface 3a.

  As described above, when the total amount of light incident on the diffusion plate 3 is M, the area of the incident region 3h is S1, and the area of the light incident surface 3e is S2, the amount of light incident on the light incident surface 3c. If the M1 (that is, the amount of light incident on the incident area 3h) is M × (S1 / (S1 + S2)), the luminance of the light exit surface 3a can be made more uniform. 6 is arranged so as to face only two end faces 2b, and when two lighting devices 1 are combined so that the end faces 2a are adjacent to each other, light leaking from one of the adjacent lighting devices 1 Is incident on the other illuminating device 1, the change in the amount of light at the peripheral edge of the light exit surface 3 a can be allowed up to about 60%. Therefore, if the amount of light incident on the incident region 3h is 0.4 × M × (S1 / (S1 + S2)) or more and 1.6 × M × (S1 / (S1 + S2)) or less, the lighting device 1 is It can be shown to the viewer that the brightness of the light exit surface 3a is uniform.

  Further, the light source 6 may be disposed so as to face only the two end faces 2a. The light source 6 may be disposed so as to face only one end surface 2a, or may be disposed only on one end surface 2b. Furthermore, the light source 6 may be disposed so as to face only three end faces 2a, 2b arbitrarily selected from the four end faces 2a, 2b. In these cases, the reflector may be arranged so as to face the end faces 2a, 2b where the light source 6 does not face. This reflecting plate is, for example, an aluminum plate and is attached to the end faces 2a and 2b. In addition, it replaces with a reflecting plate and the coating material which has reflectivity may be apply | coated to end surface 2a, 2b.

  When the reflection plate is arranged so as to face the end faces 2a and 2b where the light source 6 is not arranged, a part of the light traveling in the light guide plate 2 is directed toward the light guide plate 2 by the reflection plate. Reflected. Even in this case, it is possible to obtain substantially the same effect as the above-described embodiment. In this case, the configuration of the lighting device 1 can be simplified. In this case, since the light reflected by the reflecting plate is scattered in the light guide plate 2 and the brightness is made uniform, the light source 6 is provided at the end surfaces 2a and 2b where the reflecting plate is disposed. The first extending portion 8b that does not directly enter the light emitted from the diffusing plate 3 becomes unnecessary.

  For example, when the light source 6 is arranged so as to face only one end face 2b of the two end faces 2b and the reflection plate is arranged so as to face the other end face 2b, the one end face 2b Reflector so that the ratio of the amount of light returning to one end face 2b to the amount of incident light is equal to the ratio of the area of the dark region between adjacent light sources 6 to the area of the light exit surface 2c. When the reflectance and the concentration of the light scattering member contained in the light guide plate 2 are set, the difference between the brightness on the one end face 2b side and the brightness on the other end face 2b side can be reduced. Specifically, for example, the amount of light incident on one end surface 2b, traveling through the light guide plate 2 and reaching the other end surface 2b is 40% of the amount of light incident on one end surface 2b. The amount of light reflected by the reflector and reaching one end surface 2b is set to 15% or less and 0.4% or more of the amount of light when incident on one end surface 2b. It is possible to reduce the difference between the brightness on the end face 2b side and the brightness on the other end face 2b side.

  Further, when there are end faces 2a and 2b where the light source 6 does not face, the diffuser plate 3 faces the portion along the end faces 2a and 2b where the light source 6 faces of the peripheral edge 2d of the light exit surface 2c of the light guide plate 2. The protrusion 3b may be formed only at the position. For example, when the light source 6 is disposed so as to face only the two end surfaces 2b, the diffuser plate 3 has a portion along the end surface 2b of the peripheral portion 2d (that is, both left and right side portions of the peripheral portion 2d). The protruding portion 3b may be formed only at a position opposite to. That is, when the light source 6 is disposed so as to face only the two end surfaces 2 b, the protruding portions 3 b may be formed only on the left and right ends of the diffusion plate 3.

(Modification 2 of light source arrangement position)
FIG. 25 is a diagram for explaining an arrangement position of the light source 6 according to another embodiment of the present invention. In the embodiment described above, the position of the light source 6 arranged so as to face one end face 2a of the two end faces 2a and the position of the light source 6 arranged so as to face the other end face 2a are in the left-right direction. It may be shifted. For example, in the left-right direction, the light source 6 arranged to face the other end surface 2a may be arranged between the light sources 6 arranged to face one end surface 2a of the two end surfaces 2a. . Similarly, the position of the light source 6 arranged to face one end face 2b of the two end faces 2b and the position of the light source 6 arranged to face the other end face 2b are shifted in the left-right direction. May be.

  In this case, when a plurality of lighting devices 1 are combined, as shown in FIG. 25, the positions of the plurality of light sources 6 of one of the two lighting devices 1 adjacent to each other and the other It is possible to shift the positions of the plurality of light sources 6 of the illumination device 1. Therefore, it becomes possible to complement the decrease in brightness between the light sources 6 of one illumination device 1 by the light source 6 of the other illumination device 1, and the brightness between the light sources 6 of the other illumination device 1 can be compensated. The decrease can be supplemented by the light source 6 of one lighting device 1.

(Modification 1 of the overall configuration of the lighting device)
In the embodiment described above, the diffusion plate 3 may be disposed on both the front and rear sides of the light guide plate 2. In this case, the reflection sheet 4 and the frame 5 are not arranged behind the light guide plate 2, and the light guide plate 2 is sandwiched between the first extending portion 8b and the second extending portion 8c. In this case, in addition to the first extending portion 8 b, the second extending portion 8 c also performs a light shielding function that prevents the light emitted from the light source 6 from directly entering the diffusion plate 3.

(Modification 2 of the overall configuration of the lighting device)
In the embodiment described above, the lighting device 1 may include a high thermal conductivity sheet that contacts the light source holding member 8 and contacts the frame 5 and the bottom surface portion 9a of the case 9. In this case, the high thermal conductive sheet is disposed so as to contact the rear surface of the frame 5. Further, the peripheral edge portion of the high thermal conductive sheet is, for example, between the light source mounting portion 7a of the substrate 7 and the base portion 8a of the light source holding member 8, between the second extending portion 8c and the frame portion 5a of the frame 5, and The case 9 is disposed in a state of being sandwiched between the recessed groove portion 9d and the frame portion 5a. Further, the peripheral edge portion of the high thermal conductive sheet is in close contact with the second extending portion 8c and the frame portion 5a by the fastening force of the screws 20, 21, and is in close contact with the concave groove portion 9d and the frame portion 5a by the fastening force of the screw 22. ing.

  In this case, a reinforcing plate is disposed on the rear side of the high thermal conductivity sheet so as to contact the rear surface of the high thermal conductivity sheet. This reinforcing plate is made of an aluminum alloy having a high thermal conductivity. Further, the reinforcing plate is fixed to the frame 5 with screws, and is accommodated inside the case 9 (specifically, inside the central portion 9e). The portion of the reinforcing plate fixed to the frame 5 with screws is in close contact with the rear surface of the high thermal conductivity sheet.

  In this modification, the heat generated by the light source 6 and transmitted to the substrate 7 and the light source holding member 8 can be efficiently transmitted to the frame 5, the bottom surface portion 9a, and the reinforcing plate by the high thermal conductivity sheet. Therefore, it is possible to dissipate the heat generated by the light source 6 more efficiently. Moreover, in this modification, even if the thickness of the side surface portion 9b of the case 9 is reduced, the heat generated by the light source 6 can be dissipated more efficiently. Moreover, even if the width in the front-rear direction of the side surface portion 9b is reduced, the heat generated by the light source 6 can be more efficiently dissipated, so that the lighting device 1 can be made thinner.

  The high thermal conductivity sheet is, for example, a carbon graphite sheet, a copper foil sheet, an aluminum foil sheet, or the like. When the high thermal conductivity sheet is a carbon graphite sheet, the thermal conductivity of the high thermal conductivity sheet becomes higher. For example, even if the thickness of the high thermal conductivity sheet is about 30 μm, the heat of the light source 6 is further increased. It becomes possible to dissipate efficiently. Further, when the high thermal conductive sheet is a copper foil sheet, for example, by setting the thickness of the high thermal conductive sheet to about 0.3 mm, the heat of the light source 6 can be dissipated more efficiently. Become. Moreover, you may interpose a heat conductive sheet (thermal sheet) and a heat conductive pad between the part of the ditch | groove part 9d fastened with the frame part 5a with the screw | thread 22, and a highly heat conductive sheet.

  Moreover, the peripheral part of a highly heat conductive sheet may be arrange | positioned in the state pinched | interposed between the side part 9b of the case 9, and the base 8a, for example. Furthermore, the peripheral portion of the high thermal conductive sheet may not extend between the light source mounting portion 7a and the base portion 8a. In this case, the peripheral portion of the high thermal conductive sheet is connected to the second extending portion 8c. It arrange | positions in the state pinched | interposed between the frame part 5a and between the ditch | groove part 9d and the frame part 5a. Further, the peripheral edge portion of the high thermal conductive sheet may not extend between the second extending portion 8c and the frame portion 5a. In this case, the peripheral edge portion of the high thermal conductive sheet is the groove portion 9d. It arrange | positions in the state pinched | interposed between the frame parts 5a. Further, the reinforcing plate may not be disposed on the back side of the high thermal conductive sheet.

(Other embodiments)
Although the even number of light sources 6 are mounted on the light source mounting portion 7a of the substrate 7 in the above-described form, an odd number of light sources 6 may be mounted on the light source mounting portion 7a. Moreover, in the form mentioned above, although the light source 6 which is an LED light source is mounted in the board | substrate 7, the light source 6 mounted in the board | substrate 7 may be light sources other than an LED light source. The light source 6 may be a CCFL (Cold Cathode Fluorescent Lamp), a light bulb such as an incandescent light bulb, or a fluorescent light. Depending on the type of the light source 6, the substrate 7 on which the light source 6 is mounted may be unnecessary. In this case, the light source 6 is directly held by the light source holding member 8. In this case, the front end surface of the protrusion 2 f of the light guide plate 2 is in contact with the base 8 a of the light source holding member 8. In the embodiment described above, the protrusion 2 f is formed on the light guide plate 2, but the protrusion 2 f may not be formed on the light guide plate 2.

  In the embodiment described above, the outer peripheral surface of the diffusion plate 3 and the inner side surface 3f of the protrusion 3b are parallel to each other, but the outer peripheral surface of the diffusion plate 3 and the inner side surface 3f may not be parallel to each other. In this case, depending on the angle of the outer peripheral surface of the diffusing plate 3 with respect to the light emitting surface 2c of the light guide plate 2 and the angle of the inner side surface 3f with respect to the light emitting surface 2c, total reflection is performed on the outer peripheral surface and the inner side surface 3f. It is possible to change the amount of light to be reflected and the direction of total reflection. In the embodiment described above, the light incident surface 3c and the light emitting surface 2c are parallel to each other, but the light incident surface 3c and the light emitting surface 2c may not be parallel to each other. In this case, the amount of light incident on the light incident surface 3c from the light emitting surface 2c can be changed according to the angle of the light incident surface 3c with respect to the light emitting surface 2c.

  In the embodiment described above, the lighting device 1 is formed in a rectangular flat plate shape. However, the lighting device 1 may be formed in a square flat plate shape, or a rectangular flat plate shape other than the rectangular shape and the square shape. May be. Moreover, the illuminating device 1 may be formed in polygonal flat plates other than quadrangle, such as a pentagon, a hexagon, or an octagon. Moreover, in the form mentioned above, it may replace with the 1st extension part 8b of the light source holding member 8, and may stick the tape which has light-shielding property to the light-incidence surface 3c, or may apply the coating material which has light-shielding property. Is possible. In the above-described embodiment, the light guide plate 2 and the diffusing plate 3 contain light scattering particles, but the luminance of the light exit surface 3a (the overall brightness of the light exit surface 3a) can be made uniform. If so, the light guide plate 2 may not contain light scattering particles, and the diffusion plate 3 may not contain light scattering particles.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Light guide plate 2a, 2b End surface 2c Light emission surface 2d Peripheral part 3 Diffusion plate 3b Protrusion part 5 Frame 5a Frame part 5b Bracing part 6 Light source 8 Light source holding member 9 Case 20 Screw Z Light guide plate thickness direction Z1 First One direction

Claims (5)

A light guide plate and a light source arranged so as to face the end surface of the light guide plate and emitting light toward the end surface, and when one of the thickness directions of the light guide plate is a first direction, A diffusion plate that is disposed on the first direction side and diffuses light emitted from the light guide plate; a case that is formed in a flat box shape that is open on the first direction side; and the light guide plate and the light source are accommodated; A reinforcing frame disposed between the bottom surface of the case and the light guide plate and housed in the case;
The opening on the first direction side of the case is closed by the diffusion plate ,
The diffusion plate is disposed at a position facing at least a portion along the end surface facing the light source, at a peripheral portion of a light emitting surface which is a surface on the first direction side of the light guide plate, toward the light guide plate. With protruding protrusions,
The lighting device according to claim 1, wherein the frame is fixed to the projecting portion by a screw . The light guide plate and the diffusion plate are formed so that the shape when viewed from the thickness direction of the light guide plate is rectangular,
The said frame is provided with the flat frame part formed in a rectangular frame shape, and the flat bracing part which is formed in X shape and connects the diagonals of the said frame part. Lighting equipment. A light source holding member for holding the light source;
The lighting device according to claim 1, wherein the light source holding member is in contact with the frame. The light guide plate and the diffusion plate are formed so that the shape when viewed from the thickness direction of the light guide plate is rectangular,
The light source is disposed so as to face each of the four end faces of the light guide plate,
The said frame is provided with the flat frame part formed in a rectangular frame shape, and the flat bracing part which is formed in X shape and connects the diagonals of the said frame part. Lighting equipment. Wherein the frame, the lighting device according to claim 1, characterized in that it is formed by an aluminum alloy 4.

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