JP6653550B2 - Lighting equipment - Google Patents

Description

  The present invention relates to a flat-plate-shaped lighting device having a small thickness.

  The present applicant has proposed a flat illumination device designed so that the brightness of the light exit surface is uniform throughout the entire region including the peripheral portion (for example, see Patent Document 1). The lighting device described in Patent Literature 1 has a light guide plate, a plurality of LED light sources that emit light toward an end face of the light guide plate, and the light guide plate arranged on one side of the light guide plate in the thickness direction of the light guide plate to emit light. The light guide plate includes a diffusion plate for diffusing light, and a reflection plate disposed on the other side of the light guide plate in the thickness direction of the light guide plate. The plurality of LED light sources are linearly arranged and mounted on an LED board. The LED board is attached to the frame. The frame includes a base arranged to face an end surface of the light guide plate, and two light shielding portions extending from both ends of the base in the thickness direction of the light guide plate toward the light guide plate.

JP 2014-150049 A

  The inventor of the present application is studying the use of a flexible printed board as an LED board on which an LED light source is mounted in the lighting device described in Patent Document 1. However, Patent Literature 1 does not disclose a specific configuration of a lighting device when an LED substrate is a flexible printed circuit board.

  Therefore, an object of the present invention is to hold a light source via a plurality of light sources arranged to face an end face of a light guide plate, a flexible printed board on which a plurality of light sources are arranged and mounted, and a flexible printed board. An object of the present invention is to provide a lighting device including a light source holding member, which can be downsized in a direction in which light sources are arranged.

In order to solve the above problems, a lighting device according to the present invention includes a light guide plate, a plurality of light sources that are arranged to face an end surface of the light guide plate and emit light toward the end surface, and a flexible device on which a plurality of light sources are mounted. A printed circuit board, a light source holding member for holding the light source via the flexible printed circuit board, and a reinforcing frame, wherein the light source holding member is arranged to face the end face, and a thickness direction of the light guide plate. A first extension portion and a second extension portion that extend from each of both ends of the base portion toward the light guide plate and are arranged to sandwich the light guide plate, and the flexible printed circuit board is mounted with a plurality of light sources arranged therein. A light source mounting portion to be connected, and a band-shaped circuit connecting portion connected to the light source mounting portion so as to intersect with the light source mounting portion, wherein the light source mounting portion is provided between the first extension portion and the second extension portion. And placed in The light source holding member is formed between the base and the end face, and the light source holding member is formed with a drawing hole or a cutout for drawing out the circuit connecting portion from the light source holding member, and the frame includes a first extending portion and a second extending portion. is disposed in the second extension portion side of the pinched Rutotomoni, the light guide plate between the portions, the second extending portion, through hole shank of the screw is inserted is formed, the frame A screw hole is formed on the outer peripheral surface of the shaft portion, in which a male screw is engaged, and the light source holding member is fixed to the frame by a screw by engaging the male screw in the screw hole. .

  In the lighting device according to the aspect of the invention, the flexible printed board includes a band-shaped light source mounting portion on which the plurality of light sources are arranged and mounted, and a band-shaped circuit connection portion connected to the light source mounting portion so as to intersect with the light source mounting portion. The light source holding member has a drawing hole or a cutout for drawing out the circuit connecting portion from the light source holding member. Therefore, in the present invention, the circuit connecting portion is connected to one end or the other end in the longitudinal direction of the light source mounting portion formed in a belt shape, and the circuit is connected from one end or the other end of the light source holding member in the longitudinal direction of the light source mounting portion. As compared with the case where the connecting portion is pulled out, the size of the lighting device can be reduced in the longitudinal direction of the light source mounting portion (that is, the arrangement direction of the light sources).

  Further, in the present invention, since the circuit connection portion of the flexible printed board is drawn out from the drawing hole or the cutout formed in the light source holding member, it is possible to position the flexible printed board with respect to the light source holding member. Become. Furthermore, in the present invention, since the band-shaped circuit connecting portion connected to the light source mounting portion is drawn out from the drawing hole or the cutout portion so as to intersect with the light source mounting portion, for example, a plurality of flexible printed boards are arranged in the arrangement direction of the light sources. (Ie, even if a plurality of light source mounting portions are arranged in the longitudinal direction of the light source mounting portion), the flexible printed circuit boards overlap (specifically, the light source It is possible to prevent the mounting portions from overlapping). Therefore, in the present invention, even when a plurality of flexible printed boards are arranged so as to be arranged in the arrangement direction of the light sources, the flexible printed boards can be easily routed.

  In the present invention, the lighting device includes a diffusion plate that is disposed on a light exit surface that is one surface of the light guide plate in the thickness direction of the light guide plate and that diffuses light emitted by the light guide plate, and includes a first extension portion. Is preferably arranged on the side of the light exit surface, and a drawing hole is preferably formed at a boundary between the base and the second extension. With this configuration, the circuit connection portion can be easily routed toward the other surface of the light guide plate so that the light exit surface of the light guide plate is not covered by the circuit connection portion.

  In the present invention, for example, the circuit connecting portion is connected to a central portion of the light source mounting portion. In this case, it is possible to cause the light source holding member to hold the light source mounting portion in a well-balanced manner.

  In the present invention, the light source mounting portion is formed with an engaging projection projecting in a direction intersecting the longitudinal direction of the light source mounting portion formed in a belt shape, and the engaging projection is engaged with the light source holding member. Preferably, an engagement hole is formed. With this configuration, it is possible to more reliably position the flexible printed circuit board with respect to the light source holding member. Further, with this configuration, it is possible to suppress the fluctuation of the flexible printed circuit board with respect to the light source holding member when assembling the lighting device.

  In the present invention, it is preferable that the light source holding member is elastically deformed so that a biasing force in a direction in which the first extension portion and the second extension portion approach each other acts. With this configuration, for example, even before the light source holding member is securely fixed by a screw or the like, it is possible to prevent the light source holding member from being displaced. Therefore, the work of attaching the light source holding member can be easily performed. Further, it is possible to effectively prevent the displacement of the light source holding member after being fixed.

  In the present invention, when the direction from the base to the light guide plate is the first direction, the width of at least a part of the second extension in the first direction is wider than the width of the first extension in the first direction. Is preferred. With such a configuration, for example, the through hole into which the shaft of the screw for fixing the light source holding member is inserted is formed by using the portion of the second extending portion having a wider width in the first direction. , Can be formed at relatively free positions. With this configuration, when the light source holding member is elastically deformed so that the first extending portion and the second extending portion act on each other in a direction of approaching each other, for example, a screw or the like is used. Even before the light source holding member is securely fixed, the displacement of the light source holding member can be effectively prevented, and the displacement of the light source holding member after the fixation is more effectively performed. Can be prevented.

  In the present invention, the surface of the light source holding member is preferably silver. With this configuration, no matter what color the light source emits, it is easy to suppress discoloration of light on the light exit surface of the lighting device due to the color of the surface of the light source holding member.

  In the present invention, the light source holding member is preferably formed of an aluminum alloy. With this configuration, it is possible to reduce the weight of the light source holding member. Further, with this configuration, the heat conductivity of the light source holding member is increased, so that heat generated by the light source from the light source holding member that holds the light source can be efficiently dissipated.

  As described above, in the present invention, a plurality of light sources arranged so as to face the end surface of the light guide plate, a flexible printed board on which the plurality of light sources are arranged and mounted, and the light source held via the flexible printed board In a lighting device including a light source holding member, the size of the lighting device can be reduced in the arrangement direction of the light sources.

It is a perspective view showing the lighting installation concerning an embodiment of the invention from the front side. FIG. 2 is a front view for explaining a usage example of the lighting device shown in FIG. 1. FIG. 2 is a perspective view showing the lighting device shown in FIG. 1 as viewed from the back. FIG. 2 is an exploded perspective view of a part of the configuration of the lighting device shown in FIG. 1. FIG. 4 is a rear view of the lighting device shown in FIG. 3 with a case removed. It is sectional drawing of the EE cross section of FIG. 5 is a graph showing an angular distribution of the intensity of scattered light by a single true spherical particle. FIG. 5 is a diagram for describing a configuration of a light guide plate, a substrate, and the like illustrated in FIG. 4 from a rear side. FIG. 9 is an exploded perspective view of a part of a light guide plate, a substrate, a light source holding member, and the like illustrated in FIG. 8. It is an enlarged view of the G section of FIG. FIG. 9 is a diagram for explaining the configuration of the HH cross section of FIG. 8. FIG. 9 is a diagram for explaining a configuration of a JJ cross section of FIG. 8. It is sectional drawing of the KK cross section of FIG. It is sectional drawing of the NN cross section of FIG. FIG. 2 is a diagram illustrating a path of light until light emitted from a light source is emitted from a light emission surface of a diffusion plate in the illumination device illustrated in FIG. 1. It is a figure for explaining composition of a projection concerning another embodiment of the present invention. It is a figure for explaining composition of a projection concerning another embodiment of the present invention. It is a figure for explaining composition of a light guide plate concerning other embodiments of the present invention. It is a figure for explaining composition of a light guide plate concerning other embodiments of the present invention. It is a front view of the frame concerning other embodiments of the present invention. It is a figure for explaining composition of a light source holding member concerning other embodiments of the present invention. It is a figure for explaining composition of a light source holding member concerning other embodiments of the present invention. It is a figure for explaining composition of a light source holding member concerning other embodiments of the present invention. (A) is a graph for explaining the brightness distribution of the light emitting surface of the lighting device according to another embodiment of the present invention, and (B) is a graph according to another embodiment of the present invention. 5 is a graph for explaining the brightness distribution of the light exit surface when two lighting devices are used in combination. It is a figure for explaining arrangement position of a light source concerning other embodiments of the present invention.

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

(Overall configuration 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 illumination 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. FIG. 6 is a cross-sectional view taken along the line EE of FIG.

  The illumination device 1 of the present embodiment is a light-emitting device designed so that the brightness of the light exit surface 3a of the illumination device 1 including the peripheral portion is entirely uniform, and has a thin flat plate shape (flat panel shape). Is formed. Specifically, the lighting device 1 is formed in a rectangular flat plate shape. This lighting device 1 is used alone. Alternatively, the lighting device 1 is used in combination with a plurality of lighting devices. For example, as shown in FIG. 2A, two lighting devices 1 are used in combination in a rectangular shape, or as shown in FIG. 2B, four lighting devices 1 are combined in a rectangular shape. It has been used. The lighting device 1 is used, for example, installed on a wall surface in a room as a lighting device also serving as an interior. Note that 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 (the Z direction in FIG. 1 and the like) of the lighting device 1 is referred to as the “front-back direction”, and the longitudinal direction of the rectangular lighting device 1 (FIG. And so on, and the short 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 “up-down direction”. In addition, the front side (the Z1 direction side in FIG. 1 and the like) of the lighting device 1 in the front-back direction is defined as the “front” side, and the opposite back side (the Z2 direction side in FIG. 1 and the like) of the lighting device 1 is the opposite side. The "back (back)" side.

  The lighting device 1 includes a light guide plate 2, a diffusion plate 3 disposed in front of the light guide plate 2 to diffuse light emitted from the light guide plate 2, a reflection sheet 4 disposed behind the light guide plate 2, and a reflection sheet 4. And a reinforcing frame 5 disposed on the rear side of the vehicle. In addition, the illumination 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. A light source holding member 8 for holding the light source 6. Further, 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 illustration of the light source 6 is omitted.

  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 and the front-back direction coincide. That is, the front-back direction is the thickness direction of the light guide plate 2, and the light guide plate 2 is formed such that the shape when viewed from the front-back direction is a rectangular shape. The light guide plate 2 is arranged so that the longitudinal direction of the light guide plate 2 formed in a rectangular shape and the left-right direction coincide. The light guide plate 2 is formed with two end faces 2a orthogonal to the vertical direction and two end faces 2b orthogonal to the horizontal direction (see FIG. 4). The front surface of the light guide plate 2 is the light exit surface 2c of the light guide plate 2. The specific configuration of the light guide plate 2 will be described later.

  The diffusion plate 3 is formed in a substantially flat rectangular shape, and is arranged so that the thickness direction of the diffusion plate 3 and the front-back direction coincide. That is, the diffusion plate 3 is formed so that the shape when viewed from the front-back 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 and the left-right direction coincide. The front surface of the diffusion plate 3 is the light exit surface 3a of the diffusion plate 3. The light exit surface 3a is a light exit surface of the lighting device 1. When the light exit surface 3a is viewed from the front (that is, when the light exit surface 3a is viewed from a direction perpendicular to the light exit surface 3a), the diffuser plate 3 is positioned within the outer shape of the light exit surface 3a. The size of the lighting device 1 is large enough to accommodate the components. The specific configuration of the diffusion plate 3 will be described later.

  The reflection sheet 4 is formed of, for example, a material having a high reflectance such as an aluminum foil. Further, 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 4a that reflects light traveling in 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 the light traveling in the light guide plate 2 is reflected by the reflection surface 4a. Instead of the reflection sheet 4, a thin plate-shaped reflection plate may be disposed behind the light guide plate 2, or a reflection coating may be applied to the rear surface of the light guide plate 2 instead of the reflection sheet 4. May be.

  The frame 5 is formed of a metal plate having a high thermal conductivity. The frame 5 of the present 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 when viewed from the front-rear direction is rectangular. Specifically, the frame 5 includes a flat frame portion 5a formed in a rectangular frame shape, and a flat brace portion 5b formed in an X shape and connecting diagonals of the frame portion 5a. I have. The frame 5 is arranged so that the thickness direction of the frame 5 and the front-back direction coincide. The frame 5 is arranged so that the longitudinal direction of the rectangular frame-shaped frame portion 5a 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 arranged so as to face the end faces 2 a and 2 b of the light guide plate 2. Specifically, the light source 6 is arranged so that the center of the end faces 2a and 2b in the front-back direction and the center of the light source 6 substantially match in the front-back direction. In this embodiment, a plurality of light sources 6 are arranged so as to face each of the four end surfaces 2a and 2b of the light guide plate 2. That is, the plurality of light sources 6 are arranged along each of the four end surfaces 2a and 2b of the light guide plate 2. The light source 6 may be a package in which a red LED element, a green LED element, and a blue LED element are packaged. In this case, the light source 6 can emit light of various colors.

  The substrate 7 is a flexible printed circuit (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 belt shape. As described above, the plurality of light sources 6 are arranged so as to face each of the four end surfaces 2a and 2b of the light guide plate 2. Illumination device 1 of the present embodiment includes, for example, two substrates 7 arranged along one end surface 2a and one substrate 7 arranged along one end surface 2b. I have. That is, the lighting device 1 includes a total of six substrates 7. The lighting device 1 includes two substrates 7 that are divided in the left-right direction and are arranged along one end surface 2a. The specific configuration of the substrate 7 will be described later. FIG. 4 shows only two substrates 7. Further, three or more substrates 7 may be arranged on the end surface 2a according to the length of the end surface 2a or the length of the substrate 7. Further, two or more substrates 7 may be arranged on the end surface 2b according to 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 a plate made of an aluminum alloy into a predetermined shape. Specifically, the light source holding member 8 includes a base 8a disposed to face the end surfaces 2a and 2b of the light guide plate 2, and a first extension portion extending from both ends of the base 8a in the front-rear direction to the light guide plate 2 side. 8b and a second extending portion 8c, and are formed in an elongated rectangular groove shape as a whole. That is, the light source holding member 8 is formed such that its cross-sectional shape is substantially U-shaped (substantially U-shaped). The first extension 8b is connected to the front end of the base 8a, and the second extension 8c is connected to the rear end of the base 8a. The light source holding member 8 of this embodiment is formed 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 each of the four end surfaces 2a and 2b of the light guide plate 2, and the lighting device 1 of the present embodiment is arranged along one end surface 2a. One light source holding member 8 and one light source holding member 8 arranged along one end face 2b are provided. That is, the lighting 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 face 2a is longer than the length of the light source holding member 8 arranged along the end face 2b. The specific configuration of the light source holding member 8 will be described later.

  FIG. 4 shows only one light source holding member 8. Further, the number of the light source holding members 8 arranged along each of the end faces 2a and 2b may be plural. When it is desired that 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 be the same, the light source holding member 8 in this case is required. Assuming that the length is “the common length of the light source holding member 8”, the length of the end faces 2 a, 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 face 2b is equal to the common length of the light source holding member 8, and the length of the end face 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 face 2b, and two light source holding members 8 having a common length can be arranged so as to be continuous along the end face 2a. Further, if the length of the end face 2b is twice the common length of the light source holding member 8, and the length of the end face 2a is three times the common length of the light source holding member 8, the common length Can be arranged so as to be continuous along the end face 2b, and three light source holding members 8 having a common length can be arranged so as to be continuous along the end face 2a.

  As shown in FIG. 6, the light source mounting portion 7a and the light source 6 of the substrate 7 are arranged between the first extension portion 8b and the second extension portion 8c. Further, the light source mounting portion 7a and the light source 6 are arranged between the base 8a and the end surfaces 2a and 2b, and are arranged along the end surfaces 2a and 2b. The light guide plate 2, the reflection sheet 4, and the frame 5 are interposed between the first extension portion 8b and the second extension portion 8c. That is, the first extension portion 8b and the second extension portion 8c are arranged 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 a plate made of an aluminum alloy. In the present embodiment, the case 9 is formed of an aluminum alloy having high thermal conductivity and light weight. The case 9 is formed by press bending or the like. As shown in FIG. 4, the case 9 includes a bottom surface 9a and a side surface 9b that rises from the outer peripheral end of the bottom surface 9a toward the front side, and has a flat rectangular parallelepiped box shape whose front side is open. 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-back direction is a rectangular shape. The case 9 is disposed so that the longitudinal direction of the side surface portion 9b having a rectangular frame shape and the left-right direction coincide with each other.

  Inside the peripheral portion 9c of the bottom portion 9a, a concave groove 9d is formed so as to be depressed from the peripheral portion 9c toward the front side. This concave groove portion 9d is formed in a square ring shape. The inside of the concave groove portion 9d is a central portion 9e protruding rearward. The central portion 9e projects rearward from the peripheral edge 9c. The thickness of the bottom surface 9a is constant. That is, the thickness of the peripheral portion 9c, the thickness of the concave groove 9d, and the thickness of the central portion 9e are equal. When viewed from the front-back direction, the area of the central portion 9e is the largest. A mounting hole (not shown) for mounting the lighting device 1 to a wall, a ceiling, or the like is formed in the central portion 9e. In FIG. 4, the illustration of the concave groove portion 9d and the central portion 9e is omitted.

  As described above, inside the case 9, 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, and the bottom surface of the case 9 (that is, the bottom surface portion 9 a). The frame 5 is arranged 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 the present 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 plane. However, the outer peripheral surface of the case 9 may be arranged inside the outer peripheral surface of the diffusion plate 3.

(Configuration of diffusion plate)
FIG. 7 is a graph showing the angular distribution (A, θ) of the scattered light intensity due to a single true spherical particle.

  The diffusion plate 3 is arranged on the front side of the light guide plate 2 as described above. That is, the diffusion plate 3 is arranged on the side of the light exit surface 2c constituting the front surface of the light guide plate 2. The diffusing plate 3 includes a protruding portion 3b protruding toward the light guide plate 2 (that is, protruding rearward). The protrusion 3b is formed along the outer peripheral surface of the diffusion plate 3, and is formed in a rectangular frame shape. The outer peripheral surface of the protruding portion 3b forms 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 portion 2d (see FIG. 6) of the light exit surface 2c of the light guide plate 2. The rear surface of the protruding portion 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 emitting surface 2c is incident. The peripheral portion 2d is a portion of the light exit surface 2c facing the light incident surface 3c in the front-rear direction, and is formed in a rectangular frame shape.

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

  The diffusion plate 3 is formed 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 provided with a uniform scattering ability in volume, and the light incident on the diffusion plate 3 is scattered by the light scattering particles in the diffusion plate 3. I do. Therefore, in the present embodiment, it is possible to make the luminance distribution of the light exit surface 3a uniform. The light scattering particles contained in the diffusion plate 3 are formed of, for example, silicone particles. These light-scattering particles are contained in the diffusion plate 3 at a concentration that makes the mean free path 0.1 mm or less, for example.

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

Further, i ₁ and i ₂ in the expression (1) are represented by the expression (4). Then, a and b with the subscript “ν” in the expressions (2) to (4) are expressed by the expression (5). P (cos θ) with an upper suffix “1” and a lower suffix “ν” is a Legendre polynomial. * (Where “*” means the subscript “ν”) and its derivative. m is a relative refractive index of the light scattering particles based on the _matrix , and m = n _scatter / n _matrix . Incidentally, m is the relative refractive index of the light scattering particles relative to the matrix, the relation of the refractive index _{n scatter} and _m = _{n scatter /} n _matrix of refractive index _{n matrix} and the light scattering particles of the matrix.

  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 the 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 the scattered light intensity when A is 1.7, another is the scattered light intensity when A is 11.5, and the other is the scattered light when A is 69.2. Strength. In FIG. 7, the scattered light intensity is shown on a logarithmic scale. Therefore, the portion that appears as a slight difference in intensity in FIG. 7 is actually a very large difference.

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

When light is incident on the diffusion 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, light is emitted from the diffusion plate 3 after such scattering is sequentially performed a plurality of times. 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 tracked by the Monte Carlo method and its characteristics can be analyzed. According to this, when the incident light is unpolarized, 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 particles having the size parameter A represented by the equation (1). Assuming that the light of intensity Io is incident on the diffusion plate 3 and transmits through the distance y, and then the light intensity is attenuated to I by scattering, these relationships are expressed by the following equation (7).

Τ in this 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 Equation (8), ^s is the scattering cross section.

From the equation (7), the probability Pt (L) that the diffusion plate 3 having the length L is transmitted 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. With the above relational expression, multiple scattering in the diffusion plate 3 can be controlled using at least one of the size parameter A of light scattering particles and the turbidity τ as parameters. The light scattering particles contained in the diffusion plate 3 of the present 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 a scattering coefficient of 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 rear 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. FIG. 12 is a diagram for explaining the configuration of the JJ section of FIG.

  As described above, the substrate 7 is a flexible printed board, and a light source mounting portion 7a formed in an elongated strip shape and a circuit connection connected to the light source mounting portion 7a formed in an elongated strip shape and orthogonal to the light source mounting portion 7a. A portion 7b. The circuit connecting portion 7b is connected to a 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 engagement projection 7c that projects in a direction perpendicular to the longitudinal direction of the light source mounting portion 7a formed in a belt shape. The engagement projection 7c is formed, for example, so as to slightly project rearward. In addition, the engagement protrusions 7c are formed at a plurality of locations at predetermined intervals in the longitudinal direction of the light source mounting portion 7a. Note that the engagement projection 7c may be formed so as to slightly project toward the front side. Further, an engagement projection 7c slightly projecting toward the rear side and an engagement projection 7c slightly projecting toward the front side may be formed. Further, the engagement projection 7c may protrude in a direction inclined with respect to a direction orthogonal to the longitudinal direction of the light source mounting portion 7a. That is, the engagement convex portion 7c only needs to project in a direction intersecting the longitudinal direction of the light source mounting portion 7a.

  A plurality of light sources 6 are mounted on the light source mounting part 7a along the longitudinal direction of the light source mounting part 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 arranged along the end surface 2a, the plurality of light sources 6 are aligned in a horizontal direction. In the light source mounting portion 7a arranged along the end face 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 section 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 section 7a. The eighteen light sources 6 are mounted at a constant pitch, and nine light sources 6 are mounted on both sides of the circuit connection part 7b in the longitudinal direction of the light source mounting part 7a.

  The light guide plate 2 is formed 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 as in the case of the diffusion plate 3, and the light guide plate 2 has light scattering similar to 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 and 2b toward the substrate 7 side. That is, the light guide plate 2 is formed with a plurality of protrusions 2f that protrude from the end surfaces 2a and 2b toward the base 8a of the light source holding member 8. Specifically, the light guide plate 2 is formed with a plurality of protrusions 2f projecting outward from the end face 2a in the up-down direction and a plurality of protrusions 2f projecting outward from the end face 2b in the left-right direction. The protruding portion 2f is formed in a small shape of a flat rectangular parallelepiped having a longitudinal direction along the end surfaces 2a, 2b, and the shape of the protruding portion 2f when viewed from the front-rear direction is rectangular. . The distal end surface of the projection 2f projecting from the end surface 2a is formed in a plane perpendicular to the vertical direction, and the distal end surface of the projection 2f projecting from the end surface 2b is formed in a planar shape orthogonal to the left / right direction. In FIG. 4, illustration of the protrusion 2f is omitted.

  As shown in FIG. 8, the protrusion 2 f is in contact with the substrate 7. That is, the tip surface of the projection 2f is in contact with the surface of the light source mounting portion 7a on which the light source 6 is mounted. The protruding portions 2f are arranged between the light sources 6 arranged in a straight line, and the distal end surfaces of the protruding portions 2f are in contact with portions of the light source mounting portion 7a between the light sources 6. 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.

  As shown in FIG. 8, one adjacent end portion (specifically, an adjacent end portion of the light source mounting portion 7a) 7d of the two substrates 7 arranged along the end surface 2a has Are in contact with each other. A part of the light source mounting portion 7a is sandwiched between the base 8a of the light source holding member 8 and the projection 2f. That is, the portion between the light sources 6 and the end 7d of the light source mounting portion 7a is sandwiched between the base 8a and the protrusion 2f. The substrate 7 is fixed between the light guide plate 2 and the substrate holding member 8 by partially sandwiching the light source mounting portion 7a between the base 8a and the protrusion 2f.

  At the portion of the light guide plate 2 where the protrusion 2f is formed (inside the protrusion 2f of the light guide plate 2), a shaft of a screw 20 described later for fixing the light guide plate 2 and the light source holding member 8 to each other is provided. 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 protrusion 2f in the direction along the end faces 2a, 2b. The center of the plurality of through-holes 2g formed along the end face 2a is located slightly inside the vertical direction from the end face 2a, and the center of the plurality of through-holes 2g formed along the end face 2b. Are arranged slightly inward in the left-right direction than the end surface 2b.

  The through-hole 2g is preferably formed as far as possible in the vertical or horizontal direction as far as possible within a range where the strength of the light guide plate 2 at the portion where the through-hole 2g is formed can be ensured. By forming the through-holes 2g in this manner, it becomes possible to arrange the screws 20 at positions where the diffusion of light in the light guide plate 2 is not easily affected. That is, it is possible to arrange the screw 20 at a position on the light emitting surface 3a where luminance unevenness hardly occurs. 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 faces 2a, 2b coincide, the strength of the light guide plate 2 at the portion where the through-hole 2g is formed is ensured. In addition, the screw 20 can be arranged at a position in the light guide plate 2 that does not easily affect 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 a portion 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 will Is formed at the portion where the protrusion 2f is formed.

  As described above, the light source holding member 8 includes the base 8a, the first extension 8b connected to the front end of the base 8a, and the second extension 8c connected to the rear end of the base 8a. In the light source holding member 8 arranged along the end face 2a, the vertical width of the second extended portion 8c is constant, and the vertical width of the first extended portion 8b is also constant ( (See FIG. 9). In the light source holding member 8 arranged along the end face 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. I have. That is, the first extended portion 8b and the second extended portion 8c are formed in a slender rectangular flat plate shape.

  Further, as shown in FIG. 6 and the like, in the light source holding member 8 arranged along the end face 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 surface 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 extension 8c in the direction (first direction) from the base 8a toward the light guide plate 2 is wider than the width of the first extension 8b in this direction. The width of the second extending portion 8c in this direction is set such that the second extending portion 8c is disposed on the outer peripheral side of the concave groove 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 extension portion 8b and the second extension portion 8c. The first extension portion 8b is connected to the front end of the base portion 8a, and is disposed on the light exit surface 2c side of the light guide plate 2. The first extension 8b is disposed between the projection 3b of the diffusion plate 3 and the light guide plate 2, and is in contact with the light incident surface 3c of the projection 3b. As shown in FIG. 6, the width of the first extension 8b in the direction from the base 8a toward the light guide plate 2 is smaller than the width of the protrusion 3b in this direction.

  The first extension portion 8b has a light shielding function of preventing light emitted from the light source 6 from being directly incident on the diffusion plate 3. Further, the first extending portion 8b restricts light that enters the projecting portion 3b of the diffusion plate 3 from the peripheral edge 2d of the light exit surface 2c. The portion of the light incident surface 3c covered by the first extension portion 8b is a shielding region 3g, and the portion of the light incident surface 3c inside the shielding region 3g is an incident region 3h. . In the present 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 be 0.5 to 5 times the area of the shielding area 3g. However, it is preferable that the area of the incident area 3h is set in a range of 1 to 3 times the area of the shielding area 3g. The width of the first extension 8b in the direction from the base 8a toward the light guide plate 2 is larger than the sum of the amount of protrusion of the protrusion 2f from the end faces 2a, 2b and the thickness of the substrate 7. That is, the tip of the first extension portion 8b is located closer to the center of the light guide plate 2 than the end faces 2a and 2b. The width of the second extension 8c in the direction from the base 8a toward the light guide plate 2 is wider than the width of the protrusion 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 extended portion 8b and the second extended 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 (first state). The tip of the first extended portion 8b and the second extended portion 8c are more than when the light guide plate 2, the reflection sheet 4, and the frame 5 are not sandwiched between the extended portion 8b and the second extended portion 8c. Are elastically deformed so that the front ends thereof slightly open in the front-rear direction) and are attached to the light guide plate 2 and the frame 5. The first extension portion 8b is in contact with the light guide plate 2. Further, the first extension portion 8 b is in close contact with the light guide plate 2. The second extending portion 8c 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 extension portion 8c is in contact with the rear surface of the frame 5. Further, 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 the present embodiment is a heat dissipating member disposed between the light guide plate 2 and the second extension 8c.

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

  As shown in FIG. 11, the distal end side of the circuit connecting portion 7b is electrically connected to a circuit board 14 housed inside the case 9 (specifically, inside the central portion 9e). Specifically, the distal end side of the circuit connecting portion 7b is soldered and electrically connected to the front surface of the circuit board 14, and the soldered portion on the distal end side of the circuit connecting portion 7b is used for sealing. It is covered with resin 15. The front end side portion of the sealing resin 15 is disposed in a space 16 formed between the frame portion 5a of the frame 5 and the brace portion 5b. Note that the distal end side of the circuit connecting portion 7b may be electrically connected to the circuit board 14 via a connector.

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

  The light source holding member 8 has an engagement hole 8f with which the engagement protrusion 7c of the substrate 7 is engaged. The engagement hole 8f is formed in the second extension 8c. The engagement hole 8f is formed to penetrate the base end of the second extension 8c. The second extension 8c has a plurality of through holes 8g through which a shaft 20a of the screw 20 described later is inserted. The through hole 8g is formed to penetrate the second extension 8c. In the present 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 2g of the light guide plate 2, the through hole 8g of the light source holding member 8, and the screw 20. A second positioning means for positioning the light source 6 with respect to the light source holding member 8 is constituted by the engaging projection 7c of the substrate 7 and the engaging hole 8f of the light source holding member 8.

(Fixed structure of light guide plate, diffuser plate, frame and light source holding member)
FIG. 13 is a sectional view taken along the line KK of FIG. FIG. 14 is a cross-sectional view taken along the line NN of 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 by screws 22 (see FIGS. 3 and 6).

  As described above, the light guide plate 2 has the through holes 2g, and the light source holding member 8 has the through holes 8g. As shown in FIG. 13, the shaft portion 20a of the screw 20 is inserted into the through holes 2g and 8g. Also, a through hole 5c through which the shaft portion 20a of the screw 20 is inserted is formed in the frame portion 5a of the frame 5. The projecting portion 3b of the diffusion plate 3 is formed with a screw hole 3j into which a male screw formed on the outer peripheral surface on the distal end side of the shaft portion 20a engages. A through-hole 9g in which the head 20b of the screw 20 is arranged 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 protruded from the diffusion plate 3 by screws 20 which are inserted through the through holes 8 g, 5 c, 2 g from the rear side of the second extending portion 8 c and engage with the screw holes 3 j. It is fixed to the portion 3b. Between the inner peripheral surfaces of the through holes 8g, 5c, 2g and the outer peripheral surface of the shaft portion 20a, the light guide plate 2, the diffusion plate 3, which expands and contracts with temperature fluctuation, the frame 5, and the light source holding member 8 A gap is formed that can absorb the difference in the amount of expansion and contraction. The tip (front end) of the shaft portion 20a is disposed behind the light incident surface 3e of the diffusion plate 3. The reflection sheet 4 also has a through hole through which the shaft portion 20a is inserted.

  As shown in FIG. 14, a through hole 8h through which the shaft 21a of the screw 21 is inserted is formed in the second extension 8c, and a through hole 8h is formed in the frame 5a of the frame 5 on the outer peripheral surface of the shaft 21a. A threaded hole 5d with which a male screw to be engaged is formed. A through hole 9h in which the head 21b of the screw 21 is arranged is formed in the peripheral edge 9c 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 behind 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 the amount of expansion and contraction between the frame 5 and the light source holding member 8 which expands and contracts due to temperature fluctuations. Have been. At the position where the circuit connecting portion 7b of the substrate 7 is drawn, the circuit connecting portion 7b is also fixed to the frame 5 by screws 21 as shown in FIG.

  As shown in FIG. 6, a through-hole 9j through which the shaft 22a of the screw 22 is inserted is formed in the concave groove 9d of the case 9, and the frame 5a of the frame 5 is formed on the outer peripheral surface of the shaft 22a. A screw hole 5e is formed in which a male screw to be engaged is formed. The case 9 is fixed to the frame 5 by screws 22 that are inserted into the through holes 9j from behind the concave grooves 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 the amount of expansion and contraction between the frame 5 and the case 9 which expands and contracts due to temperature fluctuations. I have.

  In the present embodiment, after the light guide plate 2, the frame 5, and the light source holding member 8 are fixed to the protrusion 3 b of the diffusion plate 3 by the screw 20, and the light source holding member 8 is fixed to the frame 5 by the screw 21, 9 is fixed to the frame 5 by screws 22. The thickness of the bottom surface 9a of the case 9 is larger than the thickness of the heads 20b, 21b of the screws 20, 21, and as shown in FIGS. 13 and 14, the heads 20b, 21b It does not project rearward from the rear surface of the portion 9c. In addition, the amount of depression of the concave groove portion 9d on the front side 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 backward from the rear.

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

  After a part of the light emitted from the light source 6 enters the light guide plate 2 from the end faces 2a, 2b of the light guide plate 2, for example, as shown by a dashed line L1, the light exit surface 2c of the light guide plate 2 and While traveling toward the center of the light guide plate 2 while being totally reflected by the reflection surface 4a of the reflection sheet 4, the light travels while being scattered by the light scattering particles, and is eventually emitted from the light exit surface 2c. Another part of the light emitted from the light source 6 travels while being scattered by the light scattering particles without being totally reflected by the light emission surface 2c, and is emitted from the light emission surface 2c. Since the light in the light guide plate 2 is totally reflected by the light exit surface 2c and the reflection surface 4a and scattered by the light scattering particles, the luminance of the light exit surface 2c is in a uniform state.

  Part of the light emitted from the light exit surface 2c of the light guide plate 2 enters the incident area 3h of the light entrance surface 3c of the diffusion plate 3. Part of the light incident from the incident area 3h travels while being totally reflected by the inner side surface 3f of the protruding portion 3b and the outer peripheral surface of the diffusion plate 3 as indicated by the dashed line L2, while being scattered by the light scattering particles. Then, the light exits from a region of the light exit surface 3a mainly corresponding to the protruding portion 3b (that is, a peripheral portion of the light exit surface 3a). A 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 exit surface 3a.

(Main effects of this embodiment)
As described above, in the present embodiment, the portion of the light incident surface 3c of the diffusion plate 3 covered with the first extension portion 8b is the shielding region 3g, and the light emitted from the light source 6 is diffused. It does not directly enter the plate 3. Therefore, in the present embodiment, it is possible to prevent the light source 6 from appearing as a point light source on the light exit surface 3a of the diffusion plate 3. In addition, although the luminance of the peripheral portion of the light exit surface 3a close to the light source 6 tends to be higher than the luminance of the central portion of the light exit surface 3a, in the present embodiment, the luminance of the first extension portion 8b of the light entrance surface 3c is high. Since the covered portion is the shielding region 3g, the amount of light incident on the peripheral edge of the rear surface of the diffuser plate 3 (that is, the protrusion 3b) is limited, and the luminance of the peripheral edge 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 with the first extension 8b, there is a possibility that a dark portion, which is bordered by the periphery of the light exit surface 3a, may occur due to the influence of the first extension 8b. However, in the present embodiment, the light diffusing plate 3 contains light scattering particles, and the light incident on the diffusing plate 3 is scattered in the diffusing plate 3, so that the light emitting surface 3a is edged. It is possible to prevent such a dark portion from occurring.

  Further, the light emitted from the light source 6 is bright near the light source 6 and darkens as the distance increases, but in the present embodiment, the light source 6 is set so as to face each of the four end surfaces 2a and 2b of the light guide plate 2. Since they are arranged, the entire light exit surface 3a can be brightened by the light emitted from all the light sources 6. As described above, in the present 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. Further, in the present 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 the light) emitted from the light exit surface 3a are different from those in front of the light exit surface 3a. It does not change when viewed from any direction.

  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 (that is, the incident region If the amount of light M1 incident on 3h) is M × (S1 / (S1 + S2)), the brightness 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 light amount changes by about 30%, the amount of light incident on the incident area 3h is 0.7 × M × (S1 / (S1 + S2)) or more. Is less than or equal to 1.3 × M × (S1 / (S1 + S2)), it is possible for a viewer of the illuminating device 1 to see the light exit surface 3a as having uniform brightness. Further, by adjusting the size of the protruding portion 3b or by adjusting the width of the first extending portion 8b, the width of the incident area 3h can be adjusted, and the width of the incident area 3h can be adjusted. The adjustment makes it possible to adjust the amount of light emitted from the light guide plate 2 to the protruding portion 3b, so that the brightness of the light exit surface 3a can be easily equalized.

  In the present embodiment, the light source holding member 8 is elastically deformed so that the first extending portion 8b and the second extending portion 8c exert an urging force in a direction approaching each other. Therefore, in the present 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 extension portion 8 b and the second extension portion 8 c is not increased. Of the light source holding member 8 with respect to the light guide plate 2, the reflection sheet 4, and the frame 5, which is sandwiched between the light guide plate 2, the reflection sheet 4 and the frame 5. Therefore, in the present embodiment, the work of attaching the light source holding member 8 can be easily performed. In the present embodiment, the light source holding member 8 is elastically deformed so that the first extending portion 8b and the second extending portion 8c exert a biasing force in a direction approaching each other. It is possible to effectively prevent the position shift of the light source holding member 8 after being performed.

  In the present embodiment, in the light source holding member 8 arranged along the end face 2a, the vertical width of the second extending part 8c is wider than the vertical width of the first extending part 8b, and 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. 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 light source holding member 8 with respect to the light guide plate 2, the reflection sheet 4, and the frame 5 is used. The displacement can be effectively prevented, and the displacement of the light source holding member 8 after being fixed by the screws 20 and 21 can be more effectively prevented.

  In the present embodiment, the width of the second extension portion 8c is wide. Therefore, in the present embodiment, it is possible to form the through hole 8g through which the shaft portion 20a of the screw 20 is inserted at a relatively free position. Further, in the present embodiment, a plurality of protrusions 2f projecting from the end surfaces 2a and 2b of the light guide plate 2 toward the substrate 7 and contacting the substrate 7 are formed on the light guide plate 2, and the protrusions 2f of the light guide plate 2 are A through hole 2g into which the shaft portion 20a of the screw 20 is inserted is formed in the formed portion. Therefore, in the present embodiment, it becomes possible to arrange the screw 20 at a position closer to the end surfaces 2a and 2b of the light guide plate 2. That is, in the present embodiment, it is possible to arrange the screw 20 at a position where the diffusion of light in the light guide plate 2 is not easily affected, and at a position where luminance unevenness of the light exit surface 3a is unlikely to occur (in the luminance distribution). It is possible to arrange the screw 20 at a position where the influence is hardly affected. In this embodiment, the light guide plate 2, the frame 5, and the light source are screwed through the through holes 8g, 5c, and 2g from the rear side of the second extending portion 8c and engaged with the screw holes 3j of the protrusion 3b. The holding member 8 is fixed to the protrusion 3b, and a screw 20 is disposed behind the thick protrusion 3b. Therefore, in the present embodiment, the screw 20 becomes inconspicuous when viewing the light exit surface 3a.

  In the present embodiment, the light guide plate 2 is formed with a plurality of protrusions 2f that protrude from the end surfaces 2a and 2b of the light guide plate 2 toward the substrate 7 and come into contact with the substrate 7. Therefore, in the present embodiment, it is possible to maintain a gap between the light source 6 mounted on the substrate 7 and the end faces 2a, 2b according to the amount of protrusion of the protrusion 2f from the end faces 2a, 2b. Therefore, in the present embodiment, the gap between the end faces 2a and 2b and the light source 6 can be accurately maintained. As a result, in the present 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 variations in the 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 unevenness in brightness on the light exit surface 3a.

  In particular, in the present embodiment, the number of light sources 6 arranged along one end surface 2a, 2b is an even number, and the projections 2f are arranged at equal intervals between the light sources 6. 6 can be effectively suppressed from varying the gaps between the end faces 2a and 2b. Therefore, in the present embodiment, it is possible to effectively suppress unevenness in luminance on the light exit surface 3a. In the present 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. Are arranged, and the screw 20 is arranged between the light sources 6, and as described above, since the screw 20 can be arranged at a position closer to the end surfaces 2a, 2b of the light guide plate 2, Light emitted from the light source 6 is less likely to be blocked by the screw 20. Therefore, in the present embodiment, it is possible to suppress the luminance unevenness of the light exit surface 3a due to the screw 20.

  In the present embodiment, the protrusions 2f are arranged between the light sources 6 arranged in a straight line, and the distal end surfaces of the protrusions 2f are in contact with portions of the substrate 7 between the light sources 6. For this reason, in the present embodiment, for example, it is possible to reduce the size (thinning) of the illumination device 1 in the front-rear direction as compared with the case where the protrusion 2f is arranged so as to overlap the light source 6 in the front-rear direction. . Further, in the present embodiment, the light source holding member 8 includes a base portion 8a arranged to face the end surfaces 2a and 2b of the light guide plate 2, and a portion between the light sources 6 and an end portion of the light source mounting portion 7a. Since the base 7a is sandwiched between the base 8a and the protrusion 2f, the base 8a and the protrusion 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 board, the substrate 7 tends to wobble. However, by sandwiching the substrate 7 between the base 8a and the protruding portion 2f, the substrate 7 is a flexible flexible printed board. Staggering can be prevented. Further, in the present embodiment, one protrusion 2f is in contact with an adjacent end 7d of two substrates 7 arranged along the end surface 2a, and one end of the two substrates 7 is one. Is pressed by the projection 2f. Therefore, in the present embodiment, it is possible to reduce the number of protrusions 2f formed on the light guide plate 2, and as a result, it is possible to simplify the configuration of the light guide plate 2.

  In this embodiment, the substrate 7 includes a band-shaped light source mounting portion 7a and a band-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 drawing hole 8e for drawing out the circuit connecting portion 7b from the holding member 8 is formed. For this reason, in the present embodiment, 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, or to the upper end or lower end of the light source mounting portion 7a arranged along the end surface 2b. In addition, the size of the illumination device 1 can be reduced in the left-right direction and the up-down direction as compared with the case where the circuit connection portion 7b is drawn out from the longitudinal end of the light source holding member 8 formed in a square groove shape. Become. Further, in the present embodiment, since the circuit connection portion 7b is drawn out from the drawing hole 8e 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 connecting portion 7b connected to the light source mounting portion 7a is drawn out from the drawing hole 8e so as to be orthogonal to the light source mounting portion 7a, the two substrates 7 are arranged side by side 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 when the two substrates 7 are arranged side by side, the routing of the substrates 7 becomes easy.

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

  In this embodiment, the circuit connecting portion 7b is connected to the central portion of the light source mounting portion 7a. Therefore, in the present embodiment, it is possible to cause the light source holding member 8 to hold the light source mounting portion 7a in a well-balanced manner. Further, in this embodiment, the engaging projection 7c protruding rearward is formed on the light source mounting portion 7a, and the engaging hole 8f with which the engaging projection 7c engages is formed on the light source holding member 8. Therefore, in the present embodiment, it is possible to more reliably position the substrate 7 with respect to the light source holding member 8 and to suppress the fluctuation of the substrate 7 with respect to the light source holding member 8 at the time of assembling the lighting device 1. Will be 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 emission surface 3a due to the color of the surface of the light source holding member 8. Further, in the present embodiment, the light source holding member 8 is formed of an aluminum alloy, and it is not necessary to color the surface of the light source holding member 8 with silver or the like. Therefore, in the present embodiment, it is possible to reduce the manufacturing cost of the light source holding member 8. Further, 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. In addition, since the heat 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 the heat generated by the light source 6 can be generated. Heat can be efficiently transmitted to the frame 5.

  In the present embodiment, a reinforcing frame 5 is disposed behind the reflection sheet 4. Therefore, in the present embodiment, the rigidity of the lighting device 1 can be ensured even when the area of the light exit surface 3a is large. Therefore, for example, it is possible to suppress the amount of deflection of the left end side of the illumination device 1 with respect to the right end side of the illumination device 1, and as a result, to suppress the uneven brightness of the light exit surface 3 a due to the deflection of the illumination 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 brace portion 5b formed in an X shape and connecting diagonals of the frame portion 5a. Therefore, the lighting device 1 can be reduced in weight as compared with the case where the frame 5 is formed in a rectangular flat plate shape. According to the study of the inventor of the present application, when the area of the frame 5 when viewed from the front-back direction is constant, a brace connecting the diagonals of the frame portion 5a formed in a rectangular frame shape and the frame portion 5a. 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 the present embodiment, it is possible to effectively suppress unevenness in luminance of the light exit surface 3a due to the bending of the lighting device 1.

  In the present embodiment, the front surface of the second extension 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 the present embodiment, heat generated by the light source 6 can be transmitted to the frame 5 via the second extension 8c. In the present 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 9 d of the case 9, so that the heat transmitted to the frame 5 can be transmitted to the case 9. Will be possible. Therefore, in this embodiment, the heat generated by the light source 6 can be efficiently dissipated. Further, in the present embodiment, since the case 9 has the concave groove portion 9d, it is possible to increase the rigidity of the case 9. The concave groove portion 9 d of the present embodiment has both a function of efficiently dissipating the heat generated by the light source 6 and a function of increasing the rigidity of the case 9.

  Further, in the present embodiment, since the plurality of light sources 6 are arranged so as to face each of the four end faces 2 a and 2 b of the light guide plate 2, the light sources 6 transmitted to the frame 5 via the light source holding members 8 are provided. Although the heat tends to concentrate on the diagonal portions of the frame portion 5a, in the present embodiment, since the brace portions 5b connecting the diagonals of the frame portion 5a are formed in the frame 5, the brace portions 5b are used. Thus, heat concentrated on the diagonal portion of the frame portion 5a can be efficiently dissipated. Further, since the brace portion 5b is arranged 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 heat 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 more efficiently dissipated.

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

  In the above-described embodiment, 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 corrugated 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 area 3h is easily diffused on the inner side surface 3f as shown by the arrow in FIG. 16 and is easily reflected in the protrusion 3b. For this reason, it is possible to make the periphery of the light exit surface 3a brighter, and to effectively suppress the periphery of the light reflection surface 3a from becoming dark as if it were bordered. Therefore, it is possible to further equalize 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. The pitch of the unevenness and the depth (or height) of the unevenness on the inner side 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 the configuration of the protrusion 3b according to another embodiment of the present invention. In FIG. 17A, a part of the protruding part 3b and its peripheral part are shown from the rear side, and in FIG. 17B, a part of the protruding part 3b and its peripheral part are shown on one side in the left-right direction (or one side in the vertical direction). Side).

  In the above-described embodiment, a plurality of V-shaped grooves 3k may be formed on 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 and the inner side surface 3f of the diffusion plate 3. The groove 3k has a prism effect of light, and a part of the light incident from the incident area 3h is diffused on the slope of the groove 3k as shown by an arrow in FIG. Incident on. Therefore, in this case, it is possible to make the peripheral portion of the light exit surface 3a brighter, and to effectively suppress the peripheral portion of the light reflecting surface 3a from becoming dark as if it were bordered. Therefore, it is possible to further equalize the overall brightness of the light exit surface 3a.

  Note that the protrusions 3b may be formed with the unevenness shown in FIG. 16 on the inner side surface 3f, and the light incident surface 3c of the protrusion 3b may be formed with the groove 3k shown in FIG. 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 groove 3k can be arbitrarily set. Further, a so-called prism sheet may be used as the groove 3k. Further, the groove 3k may be formed only in the incident area 3h. Further, the groove 3k may be formed along the inner side surface 3f (that is, in the longitudinal direction of the board mounting portion 7a).

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

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

  In the light guide plate 2 in which the diffusion surface 2j is not formed, the vicinity of the light emitting direction of the light source 6 is bright, and the peripheral portion deviated from the light emitting direction (for example, the region between the adjacent light sources 6) is dark. If the diffusion surface 2j is formed in the peripheral portion that becomes dark, light is diffused in the peripheral portion and the peripheral portion also becomes bright. For this reason, it is possible to suppress the luminance unevenness of the peripheral portion 2d and, due to a synergistic effect with the provision of the protruding portion 3b, the peripheral portion of the light exit surface 3a is not darkened as if it is bordered, It is possible to further equalize the overall brightness of the light exit surface 3a including the peripheral portion.

  Note that the shape of the diffusion surface 2j when viewed from the front-back direction may be a shape other than a triangle having the end surfaces 2a and 2b as bases. 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 when the light reaches a certain position. Therefore, in order to make the overall brightness of the light exit surface 3a more uniform, it is necessary to gradually reduce the area of the diffusion surface 2j when viewed from the front-back direction as the distance from the light source 6 increases. preferable.

(Modification 2 of light guide plate)
FIG. 19 is a diagram for explaining a configuration of a light guide plate 2 according to another embodiment of the present invention. In FIG. 19, a part of the peripheral part 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 diffusion surface 2j is a fine uneven surface formed by performing a roughening process on a predetermined position of the peripheral portion 2d, but the diffusion surface 2j is formed of a plurality of fine lenses. It may be constituted by a convex part 2h having a shape. In this modification, each of the dots shown in FIG. 19 is a fine convex portion 2h having a convex lens shape. In the diffusion surface 2j, the aggregate of the convex portions 2h is arranged so as to be denser as approaching the intermediate position between the adjacent light sources 6 and as approaching the end surfaces 2a, 2b. That is, the aggregate of the convex portions 2h is arranged so as to become coarser as the distance from the intermediate position between the adjacent light sources 6 and as the distance from the end surfaces 2a and 2b increases.

  Also in this modified example, light is diffused in a portion between the light sources 6 which is likely to be dark, and this portion also becomes bright. For this reason, it is possible to suppress the luminance unevenness of the peripheral portion 2d and, due to a synergistic effect with the provision of the protruding portion 3b, the peripheral portion of the light exit surface 3a is not darkened as if it is bordered, It is possible to further equalize the overall brightness of the light exit surface 3a including the peripheral portion. In addition, as shown in FIG. 19, the protrusions 2h may be scattered at the center of the light exit surface 2c of the light guide plate 2 (portion where the diffusion surface 2j is not formed). In this case, it is possible to suppress color spots of the lighting device 1. Further, the number of the convex portions 2h arranged between the adjacent light sources 6 may be one. Further, the diffusion surface 2j may be constituted by a plurality of minute concave portions having a lens shape, or may be constituted by a plurality of minute concave and convex portions having a truncated cone shape. Further, the diffusion surface 2j may be constituted by a plurality of V-shaped grooves. In this case, the diffusion surface 2j has a prism effect. Further, in this case, the plurality of grooves are formed so as to radially expand from the intermediate position between the adjacent light sources 6 on the end surfaces 2a and 2b toward the inside of the diffusion plate 2, for example.

(Other modifications of the light guide plate)
In the above-described embodiment, 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 with the protrusion 2f of the light guide plate 2. It may be formed at a position deviated from the part where it is performed. In the above-described embodiment, one protruding portion 2f abuts on the adjacent end 7d of the two substrates 7 arranged along the end face 2a, but is arranged along the end face 2a. The protrusions 2f may be formed on the light guide plate 2 such that one protrusion 2f abuts on each of the adjacent ends 7d of the two substrates 7. Furthermore, in the above-described embodiment, the distal end surface of the projection 2f is in contact with the portion between the light sources 6 of the light source mounting portion 7a, but the distal end surface of the projection 2f is in the front-rear direction of the light source mounting portion 7a. May be brought into contact with a portion shifted from the mounting position of the light source 6 (that is, a front portion or a rear portion of the mounting position of the light source 6).

  Further, in the above-described embodiment, the distal end surface of the projection 2f is in contact with the substrate 7, but the distal end surface of the projection 2f may be in contact with the light source holding member 8. Specifically, the distal end surface of the projection 2f may abut on the base 8a. The substrate 7 is held in a state where it is positioned on the light source holding member 8, and the light source 6 is held on the light source holding member 8 via the substrate 7. Similarly, it is possible to maintain a gap between the light source 6 mounted on the substrate 7 and the end faces 2a, 2b according to the amount of protrusion of the protrusion 2f from the end faces 2a, 2b. Therefore, the gap between the end faces 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 8a of the light source holding member 8 with a double-sided tape or an adhesive.

(Modification of light guide plate and diffusion plate)
In the above embodiment, 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. Further, in the above-described embodiment, 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 above-described embodiment, the diffusion 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 on the light incident surface 3c of the protrusion 3b, and FIG. 16 may be formed on the inner surface 3f of the projection 3b and the groove 3k shown in FIG. 17 may be formed on the light incident surface 3c of the projection 3b. May be used in combination with the light guide plate 2 shown in FIG. In these cases, the entire brightness of the light exit surface 3a including the peripheral portion can be made more uniform.

(Modified example of frame)
FIG. 20 is a front view of a frame 5 according to another embodiment of the present invention. In the above-described embodiment, the frame 5 includes the frame portion 5a formed in a rectangular frame shape, and the brace portion 5b formed in the X shape and connecting diagonals of the frame portion 5a. In addition, for example, as shown in FIG. 20A, a case where a frame portion 5a is formed by two long sides 5g parallel to each other and two short sides 5h parallel to each other. Alternatively, 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 sides 5g and connecting the centers of the short sides 5h.

  As shown in FIG. 20B, the frame 5 may include a frame portion 5a and a connecting portion 5k formed linearly and connecting the centers of the short sides 5h. As shown in C), it may be composed of a frame portion 5a and a connecting portion 5n formed linearly and connecting the centers of the long sides 5g. Further, as shown in FIG. 20 (D), the frame 5 may be composed of a frame portion 5a and a connecting portion 5p formed in a lattice and connecting the long sides 5g and connecting the short sides 5h. good. The frame 5 may include any one of the connecting portion 5j, the connecting portion 5k, the connecting portion 5n, or the connecting portion 5p, the frame portion 5a, and the brace portion 5b. Further, the frame 5 may be constituted only by the frame portion 5a, or may be formed in a rectangular flat plate shape. Note that the lighting device 1 does not have to include the frame 5 as long as the rigidity of the lighting device 1 can be ensured.

  In the above-described embodiment, the frame 5 is formed of an aluminum alloy. However, the frame 5 may be formed of a metal plate having a high thermal conductivity other than the aluminum alloy. The frame 5 may be formed of a material having a low thermal conductivity other than the metal plate.

(Modified example of substrate)
In the embodiment described above, the circuit connecting portion 7b is connected to the center of the light source mounting portion 7a, but the circuit connecting 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 projection 7c is formed on the light source mounting portion 7a. However, the engaging projection 7c may not be formed on the light source mounting portion 7a. In this case, it is not necessary to form the engaging hole 8f in the light source holding member 8. Furthermore, in the above-described embodiment, the circuit connecting 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 connecting portion 7b is connected to one end of the light source mounting portion 7a formed in a belt shape. It may be connected to the other end. In this case, the circuit connection portion 7b is drawn out from the longitudinal end of the light source holding member 8 formed in a square groove shape. In this case, it is not necessary to form the drawing hole 8e in the light source holding member 8. Further, in the above-described embodiment, the board 7 is a flexible printed board, but the board 7 may be a rigid board such as a glass epoxy board. In this case, for example, the board 7 and the circuit board 14 are electrically connected via a flexible printed board, a lead wire, or the like.

  In the above-described embodiment, the circuit connecting portion 7b is connected to the light source mounting portion 7a so as to be orthogonal to the light source mounting portion 7a, but the circuit connecting portion 7b is connected to the direction orthogonal to the longitudinal direction of the light source mounting portion 7a and the light source mounting portion. It may be connected to the light source mounting part 7a so as to be inclined with respect to the longitudinal direction of the part 7a. That is, the circuit connection portion 7b only needs to be connected to the light source mounting portion 7a so as to cross the light source mounting portion 7a. If the circuit connecting portion 7b is connected to the light source mounting portion 7a so as to cross the light source mounting portion 7a, the same effect as in the above-described embodiment can be obtained. That is, in this case, 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 or the upper end or the lower end of the light source mounting portion 7a arranged along the end surface 2b. The size of the lighting device 1 in the left-right direction and the up-down direction can be reduced as compared with the case where the circuit connection portion 7b is drawn out from the longitudinal end of the light source holding member 8 formed in a square groove shape. . Also in this case, since the circuit connection portion 7b can be pulled out from the drawing hole 8e formed in the light source holding member 8, the substrate 7 can be positioned with respect to the light source holding member 8. Further, in this case, since the circuit connecting portion 7b connected to the light source mounting portion 7a is drawn out from the drawing hole 8e so as to cross the light source mounting portion 7a, the two substrates 7 are arranged along the end face 2a. , It is possible to prevent the substrates 7 from overlapping each other.

(Modification 1 of light source holding member)
FIG. 21 is a diagram for explaining a configuration of a light source holding member 8 according to another embodiment of the present invention. In the above-described embodiment, 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 to this, for example, as shown in FIG. 21, a plurality of recesses 8j that are recessed from the tip of the first extension 8b toward the base 8a may be formed in the first extension 8b. The plurality of concave portions 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 opens between the adjacent light sources 6. The light emitted from the light source 6 is shielded by the projection 8k so as not to directly enter the projection 3b, and also enters the projection 3b from the recess 8j while passing around the projection 8k.

  In this modification, the brightness of the light incident on the protruding portion 3b at a position close to the light source 6 and the light source, as compared with the case where the first extension portion 8b is formed in an elongated rectangular shape, It is possible to reduce the difference between the brightness of the light incident on the protruding portion 3b at a position distant from 6 and the brightness. Therefore, the brightness of the entire light exit surface 3a can be made more uniform. Note that the shape of the projection 8k may be a trapezoidal shape or a triangular shape having a narrow tip, as long as the difference in brightness of light incident on the protrusion 3b between the light sources 6 can be reduced. The tip of the projection 8k may have a circular shape.

(Modification 2 of light source holding member)
FIG. 22 and FIG. 23 are views for explaining the configuration of the 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 to this, for example, as shown in FIG. 22, a plurality of recesses 8n that are recessed from the tip of the second extension 8c toward the base 8a may be formed in the second extension 8c. The plurality of concave portions 8n are formed at regular intervals along the longitudinal direction of the light source mounting portion 7a of the substrate 7. The recess 8n is formed between the adjacent through holes 8g and 8g and between the adjacent through holes 8g and 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 them. In this modification, as shown in FIG. 22, the width of the portion of the second extension 8c where the projection 8p is formed is wider than the width of the first extension 8b. That is, the width of a part of the second extended portion 8c is wider than the width of the first extended portion 8b. In the above-described embodiment, the width of the second extension 8c is wider than the width of the first extension 8b, but the width of the second extension 8c is smaller than that of the first extension 8b. It may be less than the width.

  In the above-described embodiment, the drawing hole 8e for drawing out the circuit connecting portion 7b of the substrate 7 from the light source holding member 8 is formed at the boundary between the base 8a and the second extending portion 8c. May be formed only on the base 8a, or may be formed only on the second extension 8c. That is, the extraction hole 8e may be formed so as not to penetrate the second extension 8c, or may be formed so as not to penetrate the base 8a similarly to the engagement hole 8f. However, when the drawing hole 8e is formed so as to penetrate the base 8a and the second extending portion 8c at the boundary portion between the base 8a and the second extending portion 8c, the circuit connecting portion 7b is formed in the drawing hole 8e. It becomes easy to pass through, and the assembling work of the lighting device 1 becomes easy.

  Further, in the above-described embodiment, the drawing hole 8e is formed in the light source holding member 8, but as shown in FIG. 23, the notch 8r for pulling out the circuit connecting portion 7b from the light source holding member 8 is provided with the light source holding member. 8 may be formed. In this case, the notch 8r is formed so as to be cut from the tip of the second extension 8c toward the base 8a. However, in consideration of the rigidity of the light source holding member 8, it is preferable that the drawing hole 8e is formed in the light source holding member 8 as in the above-described embodiment. In the above-described embodiment, the engagement hole 8f is formed to penetrate the base end of the second extension 8c. However, the engagement hole 8f is located behind the base 8a similarly to the extraction hole 8e. It may be formed so as to penetrate the end portion and the base end portion of the second extension portion 8c. However, when the engagement hole 8f is formed so as not to penetrate the rear end of the base 8a as in the above-described embodiment, the engagement hole 8f is formed so as to penetrate the rear end of the base 8a. It is possible to reliably position the engagement projection 7c as compared with the case where the engagement is performed.

  In the above-described embodiment, the light source holding member 8 is made of an aluminum alloy, and the surface of the light source holding member 8 has a silver color. However, the light source holding member 8 has a silver surface. The surface of the member 8 may be plated, or the surface of the light source holding member 8 may be colored. In the above-described embodiment, the light source holding member 8 is formed of an aluminum alloy, but the light source holding member 8 may be formed of stainless steel. Also in this case, it is not necessary to color the surface of the light source holding member 8 in silver. 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 formed of a copper alloy, and the surface of the light source holding member 8 may have a copper color. However, when 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 light emitting surface 3a The color of light may change to yellowish. If the light source holding member 8 is formed of a copper alloy, it becomes possible to enhance the heat radiation of the light source 6 and the thermal conductivity to the frame 5.

(Modification 1 of Arrangement Position of Light Source)
FIG. 24A is a graph for explaining the brightness distribution of the light exit surface 3a of the illumination device 1 according to another embodiment of the present invention, and FIG. 7 is a graph for explaining the brightness distribution of the light exit surface 3a when two illumination devices 1 according to the embodiment are used in combination.

  In the embodiment described above, the light source 6 is arranged so as to face the four end faces 2a and 2b of the light guide plate 2, but the light source 6 may be arranged so as to face only the two end faces 2b. In this case, since the light leaks from the end surface 2a where the light source 6 is not arranged, the brightness of the peripheral portion of the light exit surface 3a close to the end surface 2a is lower 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. Note that both ends of the graph in FIG. 24A indicate the brightness of the peripheral portion of the light exit surface 3a close to the end surface 2a. The two-dot chain line in FIG. 24A schematically shows light leakage from the end face 2a.

  On the other hand, as shown in FIG. 2A, when two lighting devices 1 are combined so that the end faces 2a are adjacent to each other, as shown by the arrow in FIG. Light leaked from one end face 2a of the end faces 2a enters the other end face 2a, and light leaked from the other end face 2a enters the one end face 2a. Therefore, even when the light source 6 is arranged so as to face only the end face 2b, if the two lighting apparatuses 1 are combined so that the end faces 2a are adjacent to each other, a joint between the two lighting apparatuses 1 is formed. In this case, the brightness of the light exit surface 3a can be equalized without decreasing the brightness of the light exit surface 3a.

  As described above, assuming that 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 (that is, the amount of light incident on the incident area 3h) M1 is M × (S1 / (S1 + S2)), the luminance of the light exit surface 3a can be made more uniform. 6 are arranged so as to face only the two end surfaces 2b, and when two lighting devices 1 are combined so that the end surfaces 2a are adjacent to each other, light leaking from one of the adjacent lighting devices 1 Is incident on the other illuminating device 1, so that the change in the amount of light at the periphery of the light exit surface 3a can be allowed up to about 60%. Therefore, if the amount of light incident on the incident area 3h is 0.4 × M × (S1 / (S1 + S2)) or more and 1.6 × M × (S1 / (S1 + S2)) or less, the lighting device 1 is turned off. It is possible for a viewer to see that the luminance of the light exit surface 3a is uniform.

  Further, the light source 6 may be arranged so as to face only the two end faces 2a. Further, the light source 6 may be arranged so as to face only one end face 2a, or may be arranged only on one end face 2b. Further, the light source 6 may be arranged 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 and 2b where the light source 6 does not face. This reflection plate is, for example, an aluminum plate and is attached to the end faces 2a and 2b. Note that, instead of the reflection plate, a paint having reflectivity may be applied to the end faces 2a and 2b.

  When the reflector 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 that has traveled through the light guide plate 2 is directed toward the light guide plate 2 by the reflector. Is reflected. Even in this case, it is possible to obtain substantially the same effect as in 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 reflector is scattered in the light guide plate 2 and the brightness is made uniform, the light sources 6 are disposed on the end faces 2a and 2b where the reflectors are arranged. There is no need for the first extension portion 8b that does not directly make the light emitted by the light incident on the diffusion plate 3.

  For example, in the case where the light source 6 is arranged so as to face only one end face 2b of the two end faces 2b and the reflector is arranged so as to face the other end face 2b, the one end face 2b The reflecting plate is set so that the ratio of the amount of light returning to the one end face 2b to the amount of incident light and the ratio of the area of the dark region between the adjacent light sources 6 to the area of the light exit surface 2c are equal. And the density of the light scattering member contained in the light guide plate 2, it is possible to reduce the difference between the brightness on one end face 2 b side and the brightness on the other end face 2 b side. Specifically, for example, the amount of light that enters one end face 2b, travels through the light guide plate 2, and reaches the other end face 2b is 40% of the amount of light that enters the one end face 2b. 15% or more, and 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 diffusion plate 3 faces a portion of the peripheral edge 2d of the light exit surface 2c of the light guide plate 2 along the end faces 2a and 2b where the light source 6 faces. 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 includes a portion of the peripheral portion 2d along the end surface 2b (that is, both left and right portions of the peripheral portion 2d). The projection 3b may be formed only at the position facing (3). That is, when the light source 6 is arranged so as to face only the two end surfaces 2 b, the protrusions 3 b may be formed only on the left and right ends of the diffusion plate 3.

(Modification 2 of Arrangement Position of Light Source)
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 above-described embodiment, the position of the light source 6 disposed so as to face one end surface 2a of the two end surfaces 2a and the position of the light source 6 disposed so as to face the other end surface 2a are in the horizontal direction. It may be shifted. For example, in the left-right direction, between the light sources 6 arranged so as to face one of the two end faces 2a, the light source 6 arranged so as to face the other end face 2a may be arranged. . Similarly, the position of the light source 6 arranged so as to face one end face 2b of the two end faces 2b and the position of the light source 6 arranged so as 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 lighting device 1. Therefore, the decrease in brightness between the light sources 6 of the one lighting device 1 can be complemented by the light source 6 of the other lighting device 1, and the brightness between the light sources 6 of the other lighting device 1 can be reduced. The decrease can be complemented by the light source 6 of the one lighting device 1.

(Modification 1 of overall configuration of lighting device)
In the embodiment described above, the diffusion plates 3 may be arranged on both sides before and after the light guide plate 2. In this case, the reflection sheet 4 and the frame 5 are not disposed behind the light guide plate 2, and the light guide plate 2 is sandwiched between the first extended portion 8b and the second extended portion 8c. In this case, in addition to the first extended portion 8b, the second extended portion 8c also has a light blocking function of preventing light emitted from the light source 6 from being directly incident on the diffusion plate 3.

(Modification 2 of overall configuration of lighting device)
In the above-described embodiment, the lighting device 1 may include a high thermal conductive sheet that contacts the light source holding member 8 and contacts the frame 5 and the bottom surface 9 a of the case 9. In this case, the high heat conductive sheet is arranged so as to contact the rear surface of the frame 5. Further, the peripheral portion of the high heat 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 Are arranged between the concave groove 9d of the case 9 and the frame 5a. The peripheral portion of the high thermal conductive sheet is in close contact with the second extended portion 8c and the frame portion 5a by the fastening force of the screws 20 and 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 arranged behind the high thermal conductive sheet so as to contact the rear surface of the high thermal conductive sheet. This reinforcing plate is formed of an aluminum alloy having high thermal conductivity. The reinforcing plate is fixed to the frame 5 by screws, and is housed inside the case 9 (specifically, inside the central portion 9e). The portion of the reinforcing plate fixed to the frame 5 by screws is in close contact with the rear surface of the high heat conductive 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 9a and the reinforcing plate by the high heat conductive sheet. Therefore, heat generated in the light source 6 can be more efficiently dissipated. Further, in this modification, even if the thickness of the side surface 9b of the case 9 is reduced, the heat generated by the light source 6 can be more efficiently dissipated. Further, even if the width of the side surface portion 9b in the front-rear direction 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 conductive sheet is, for example, a carbon graphite sheet, a copper foil sheet or an aluminum foil sheet. When the high thermal conductive sheet is a carbon graphite sheet, the thermal conductivity of the high thermal conductive sheet becomes higher. For example, even if the thickness of the high thermal conductive sheet is about 30 μm, the heat of the light source 6 is reduced. 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 more efficiently dissipated. Become. Further, a heat conductive sheet (thermal sheet) or a heat conductive pad may be interposed between the recessed groove 9d, which is fastened to the frame 5a by the screw 22, and the high heat conductive sheet.

  Further, the peripheral portion of the high heat conductive sheet may be disposed, for example, in a state of being sandwiched between the side surface 9b of the case 9 and the base 8a. Further, the peripheral portion of the high thermal conductive sheet does not need to extend to a position between the light source mounting portion 7a and the base 8a. In this case, the peripheral portion of the high thermal conductive sheet does not extend to the second extended portion 8c. It is arranged in a state sandwiched between the frame 5a and between the concave groove 9d and the frame 5a. Further, the peripheral portion of the high thermal conductive sheet does not need to extend to between the second extending portion 8c and the frame portion 5a. In this case, the peripheral portion of the high thermal conductive sheet is It is arranged in a state sandwiched between the frame portion 5a. Further, the reinforcing plate may not be disposed behind the high thermal conductive sheet.

(Other embodiments)
In the embodiment described above, an even number of light sources 6 are mounted on the light source mounting portion 7a of the substrate 7, but an odd number of light sources 6 may be mounted on the light source mounting portion 7a. Further, in the above-described embodiment, the light source 6 which is an LED light source is mounted on the substrate 7, but the light source 6 mounted on the substrate 7 may be a light source other than the LED light source. Further, 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 not be necessary. In this case, the light source 6 is directly held by the light source holding member 8. Further, in this case, the distal end surface of the projection 2 f of the light guide plate 2 contacts the base 8 a of the light source holding member 8. In the above-described embodiment, the projection 2f is formed on the light guide plate 2. However, the projection 2f may not be formed on the light guide plate 2.

  In the above-described embodiment, 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, but the outer peripheral surface of the diffusion plate 3 and the inner side surface 3f do not have to be parallel. In this case, total reflection occurs at the outer peripheral surface and the inner side surface 3f of the diffusion plate 3 according to the angle of the outer peripheral surface of the diffuser plate 3 with respect to the light exit surface 2c of the light guide plate 2 and the angle of the inner side surface 3f with respect to the light exit surface 2c. It is possible to change the amount of light to be emitted and the direction of total reflection. In the above-described embodiment, the light incident surface 3c and the light exit surface 2c are parallel, but the light incident surface 3c and the light exit surface 2c do not have to be parallel. In this case, it is possible to change the amount of light that enters the light incident surface 3c from the light exit surface 2c according to the angle of the light incident surface 3c with respect to the light exit surface 2c.

  In the above-described embodiment, 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 may be formed in a rectangular flat plate shape other than a rectangular shape and a square shape. May be. Further, the lighting device 1 may be formed in a polygonal flat plate shape other than a quadrangle such as a pentagon, a hexagon or an octagon. In the above-described embodiment, instead of the first extension portion 8b of the light source holding member 8, a light-shielding tape may be attached to the light incident surface 3c, or a light-shielding paint may be applied. It is possible. In the above-described embodiment, light scattering particles are contained in the light guide plate 2 and the diffusion plate 3, 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 Illumination device 2 Light guide plate 2a, 2b End surface 2c Light emission surface 3 Diffusing plate 6 Light source 7 Substrate (flexible printed circuit board)
7a Light source mounting part 7b Circuit connection part 7c Engagement convex part 8 Light source holding member 8a Base part 8b First extension part 8c Second extension part 8e Outlet hole 8f Engagement hole 8r Notch part Z Thickness direction of light guide plate

Claims (8)

A light guide plate, a plurality of light sources arranged to face an end face of the light guide plate and emitting light toward the end face, a flexible printed board on which a plurality of the light sources are mounted, and the flexible printed board via the flexible printed board. A light source holding member for holding the light source, and a frame for reinforcement are provided,
The light source holding member is disposed so as to face the end face, and extends from each of both ends of the base in the thickness direction of the light guide plate to the light guide plate side and is disposed so as to sandwich the light guide plate. A first extension portion and a second extension portion,
The flexible printed circuit board includes a band-shaped light source mounting portion on which the plurality of light sources are arranged and mounted, and a band-shaped circuit connection portion connected to the light source mounting portion so as to intersect with the light source mounting portion,
The light source mounting portion is disposed between the first extension portion and the second extension portion, and is disposed between the base portion and the end surface,
The light source holding member is formed with a drawing hole or a notch for pulling out the circuit connection portion from the light source holding member,
The frame is sandwiched between said second elongated portion and the first extending portion Rutotomoni, disposed in said second elongated portion side of the light guide plate,
The second extension portion has a through hole through which the shaft portion of the screw is inserted,
In the frame, a screw hole is formed in which an external thread formed on the outer peripheral surface of the shaft portion is engaged,
The lighting device, wherein the light source holding member is fixed to the frame by the screw by engaging the male screw with the screw hole . The light guide plate includes a diffusion plate that is disposed on a light exit surface that is one surface of the light guide plate in a thickness direction of the light guide plate and diffuses light emitted by the light guide plate,
The first extension portion is disposed on a side of the light exit surface,
The lighting device according to claim 1, wherein the drawing hole is formed at a boundary between the base and the second extension.   The lighting device according to claim 1, wherein the circuit connection unit is connected to a central portion of the light source mounting unit. The light source mounting portion is formed with an engagement projection projecting in a direction intersecting the longitudinal direction of the light source mounting portion formed in a belt shape,
The lighting device according to any one of claims 1 to 3, wherein the light source holding member has an engagement hole with which the engagement protrusion engages.   The said light source holding member is elastically deformed so that the said 1st extended part and the said 2nd extended part may apply the urging | biasing force of the direction approaching mutually. The Claims 1 to 4 characterized by the above-mentioned. The lighting device according to claim 1. When a direction from the base toward the light guide plate is a first direction,
The width of at least a part of the second extending portion in the first direction is wider than the width of the first extending portion in the first direction. The lighting device according to any one of the above.   The lighting device according to claim 1, wherein a surface of the light source holding member is silver.   The lighting device according to claim 1, wherein the light source holding member is formed of an aluminum alloy.

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