Planar lighting device

Abstract

To effectively prevent generation of rattling noise by support of an elastic member, even when a length of a light-incident side is long.SOLUTION: A planar lighting device includes a light guide plate, a plurality of light sources, an elastic member, and a bottom frame. Light enters the light guide plate from a light-incident surface. The plurality of light sources irradiates the light-incident surface of the light guide plate with light. The elastic member supports the light guide plate while pressing the same. The bottom frame houses the light guide plate, the plurality of light sources, and the elastic member. The bottom frame has a pillar projecting in a thickness direction, on a position opposed to the substantial center in a longitudinal direction, of the light-incident surface of the light guide plate. The light guide plate has a groove to be engaged with the pillar, at the substantial center in the longitudinal direction of the light-incident surface. The elastic member presses a side at a non-light-incident side of the light guide plate to the light-incident side.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a surface lighting device. [Background technology]

[0002] A so-called edge-light type planar illumination device is known in which light is incident from a light-entering side surface of a light guide plate and the light is emitted from one main surface of the light guide plate (see, for example, Patent Documents 1 and 2). Such planar illumination devices are used as backlights in liquid crystal display devices.

[0003] In addition, since the light guide plate, which is a component of the surface lighting device, expands and contracts due to temperature changes, a clearance is required between the side wall of the bottom frame that houses them and the light guide plate in the expansion and contraction direction. If the light guide plate is simply placed on the surface lighting device due to the presence of the clearance, the light guide plate will hit the bottom frame due to vibrations applied to the surface lighting device, generating rattle noise and causing discomfort to the user. Therefore, in the past, the corners of the non-light-entering side of the light guide plate were generally supported by an elastic member such as rubber, and the light guide plate was pressed against the light-entering side to prevent vibration and absorb the expansion and contraction of the light guide plate due to temperature changes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-222331 A [Patent Document 2] JP 2015-176752 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, generally, the corners of the non-light-entering side of the light guide plate are supported by the elastic member, which is preferable because it is a simple structure and can provide stable support. However, it is becoming difficult to adopt such a structure in a large-sized (horizontally elongated due to the enlargement of the light-entering side) surface lighting device for in-vehicle use, etc. That is, the horizontal elongation of the light guide plate requires a large clearance between the side wall of the bottom frame, and the length of the elastic member in the stretching direction to absorb the clearance also becomes large. However, since the thickness of the light guide plate is not much different from the conventional one, the aspect ratio of the thickness and length of the elastic member is reversed, and the elastic member floats up and pops out in a compressed state, making it impossible to design to stably support the light guide plate. It is possible to provide an elastic member only on the edge of the non-light-entering side instead of the corners of the non-light-entering side of the light guide plate and press the light guide plate against the light-entering side, but it is difficult to restrict the movement of the light guide plate in the long side direction, and it is not possible to effectively prevent the generation of rattle noise.

[0006] The present invention has been made in consideration of the above, and aims to provide a surface lighting device that can effectively prevent the generation of rattle noise by being supported by an elastic member, even if the side on the light incident side is long. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, a planar lighting device according to one aspect of the present invention includes a light guide plate, a plurality of light sources, an elastic member, and a bottom frame. The longitudinal side The light enters from the light-entering side surface. The plurality of light sources irradiate light onto the light-entering side surface of the light guide plate. The elastic member presses and supports the light guide plate. The bottom frame accommodates the light guide plate, the plurality of light sources, and the elastic member. The bottom frame is disposed at a position facing approximately the center of the light-entering side surface of the light guide plate in the longitudinal direction. only The light guide plate has pillars protruding in a thickness direction. The above The light-entering side surface has a groove at a substantially central portion in a longitudinal direction thereof for engaging with the pillar. Side Press it towards the light entrance side.

[0008] In the surface lighting device according to one aspect of the present invention, even if the side on the light incident side is long, the generation of rattle noise can be effectively prevented by support provided by the elastic member. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing the appearance of a surface illumination device according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the main components of the surface illumination device. [Diagram 3] FIG. 3 is an external perspective view of the bottom frame. [Figure 4] FIG. 4 is an external perspective view of the elastic member. [Diagram 5] FIG. 5 is a perspective view showing a state in which the light guide plate is supported by the pillars, the elastic members, and the legs. [Figure 6] FIG. 6 is a diagram showing an example of the positional relationship between the grooves of the light guide plate, the pillars of the bottom frame, and the light emitted from the light source. [Figure 7] FIG. 7 is an end view showing another example of the configuration of the elastic member in the embodiment. [Figure 8] FIG. 8 is an end view showing another example of the configuration of the elastic member in the embodiment. [Figure 9] FIG. 9 is an end view showing another example of the configuration of the elastic member in the embodiment. [Figure 10] FIG. 10 is a perspective view showing an example of fixing the optical sheet with pins. [Figure 11] FIG. 11 is a perspective view showing a configuration example of a substrate on which light sources are arranged. [Figure 12] FIG. 12 is a perspective view showing an example of the configuration of double-sided tape for fixing the light guide plate at the center of the long side on the light incident side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a planar lighting device according to an embodiment will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, the dimensional relationship of each element in the drawings, the ratio of each element, etc. may differ from reality. The drawings may also include parts with different dimensional relationships and ratios. In principle, the contents described in one embodiment or modified example are similarly applied to other embodiments or modified examples.

[0011] Fig. 1 is an external perspective view of a surface lighting device 1 according to an embodiment, as viewed from the light emission surface side. For ease of explanation, in Fig. 1, the direction along the long side of the housing of the surface lighting device 1 is defined as the X-axis direction, the direction along the short side of the housing is defined as the Y-axis direction, and the direction along the thickness of the housing is defined as the Z-axis direction.

[0012] 1, the surface illumination device 1 has a generally rectangular and generally flat outer shape, with a top frame 19 exposed at the end of the light emission surface on the front side of the figure. Also, a bottom frame 2 is provided on the back side. The top frame 19 is formed with an opening 19a through which light exits. The opening 19a exposes the optical sheet 15 inside.

[0013] Extending from the surface illumination device 1 in the negative direction of the Y axis is a connection portion 11d of the internal substrate 11, which is used for electrical connection to the outside. The top frame 19 is made of resin or the like. The bottom frame 2 is made of die-cast metal material or the like. When the surface illumination device 1 is used as a backlight for a liquid crystal display device or the like, the liquid crystal display device or the like is attached to the side of the opening 19a.

[0014] 1 shows a substantially flat housing, the housing may be a curved plate. In this case, the bottom frame 2, the top frame 19, and the internal light guide plate (described later) are also curved.

[0015] Fig. 2 is an exploded perspective view of the main components of the planar lighting device 1, as seen from the light emission surface side, similar to Fig. 1. In Fig. 2, the planar lighting device 1 has a bottom frame 2, which accommodates a reflector 3, a spacer 5, an elastic member 6, a substrate 11, a light source 12, a light guide plate 13, optical sheets 14 to 16, a spacer 17, and a top frame 19.

[0016] The bottom frame 2 is substantially box-shaped with a bottom and no lid, and is formed by die-casting a metal material or the like. The structure of the bottom frame 2 will be described in detail later. The reflector 3 is a substantially rectangular thin plate, and is placed inside the bottom of the bottom frame 2. The side of the reflector 3 facing the light guide plate 13 is a reflective surface, which returns light leaking from the light guide plate 13 to the back side (non-emitting side) toward the light guide plate 13, improving light efficiency. A predetermined range from the center of the lower side of the reflector 3 in the figure is cut out to expose double-sided tapes 7 and 8 described later. In addition, a connecting portion of the substrate 11 described later is directly fixed to the bottom frame 2 on the back side of the reflector 3 (bottom frame 2 side).

[0017] A strip-shaped spacer 5 is fixed to the inside of the side wall of the bottom frame 2 except for the light-entering side (the side of the lower edge in the figure) via a strip-shaped double-sided tape 4. The spacer 5 prevents the light guide plate 13 and the optical sheets 14-16 from directly hitting the bottom frame 2 and generating rattle noise, and also improves light efficiency by returning light leaking from the sides of the light guide plate 13 and the optical sheets 14-16.

[0018] A strip-shaped substrate 11 is fixed to the inside of the side wall on the light-entering side of the bottom frame 2 via a strip-shaped double-sided tape 9. A plurality of light sources 12 such as LEDs (Light Emitting Diodes) are arranged on the substrate 11. Details of the substrate 11 will be described later, but a portion of the substrate 11 is bypassed by a connecting portion 11b, and the connecting portion 11b is fixed to the inside of the bottom of the bottom frame 2 with the double-sided tape 10.

[0019] The light guide plate 13 has a substantially rectangular and flat outer shape, and is made of transparent resin such as polycarbonate. It guides light incident from the light incident side at the bottom of the figure to the terminal end, and emits the light from the main surface at the front side by the action of the optical element on the back side. The light guide plate 13 is arranged so that the light incident side at the bottom of the figure faces the light source 12 on the substrate 11, and is fixed to the inside of the bottom of the bottom frame 2 by the double-sided tape 8 arranged in a scattered island shape between the multiple light sources 12 and the strip-shaped double-sided tape 7 in a predetermined range at the approximately center of the longitudinal direction of the light incident side. In addition, the long side of the light guide plate 13 on the non-light incident side (the upper side in the figure) is pressed and supported by two elastic members 6 made of synthetic rubber or the like, and the long side on the light incident side (the lower side in the figure) is supported by legs protruding from the bottom frame 2. Details will be described later.

[0020] On the exit surface side of the light guide plate 13, optical sheets 14 to 16 each having a substantially rectangular shape are laminated in order. The optical sheet 14 is, for example, a diffuser (diffusion film). The optical sheet 15 is, for example, a prism sheet such as BEF (brightness enhancing film manufactured by 3M). The optical sheet 16 is, for example, a prism sheet such as DBEF (brightness enhancing film manufactured by 3M). A frame-shaped spacer 17 is placed on the exit surface side of the optical sheet 16, and a frame-shaped top frame 19 is fixed thereto via a frame-shaped double-sided tape 18.

[0021] Fig. 3 is an external perspective view of the bottom frame 2. In Fig. 3, the portion enclosed in a large dashed circle is a partially enlarged view of the portion enclosed in a small dashed circle connected by a dashed line, and if no unique coordinate axis is shown, it is the same as the coordinate axis of the basic perspective view, and if a unique coordinate axis is shown, it is a view seen from a different angle along that coordinate axis.

[0022] In Fig. 3, the bottom frame 2 has a bottom 2a and side walls 2b surrounding the bottom 2a on all four sides. A pillar 2c protruding in the thickness direction is provided at approximately the center of the lower side wall 2b in the figure. The pillar 2c is connected to the side wall 2b on the light incident side of the bottom frame 2 and protrudes from the bottom 2a of the bottom frame 2 in the thickness direction. This increases the strength of the pillar 2c and enables the light guide plate 13 to be stably supported. As described below, a groove 13c provided on the light incident side of the light guide plate 13 engages with the pillar 2c to restrict the movement of the light guide plate 13 in the longitudinal direction (X-axis direction).

[0023] Furthermore, a pin 2d is provided on the emission side of pillar 2c so as to protrude in the emission direction. As will be described later, pin 2d engages with a hole provided on the light incident side of optical sheets 14-16 (FIG. 2) to fix optical sheets 14-16. This makes it easy to fix optical sheets 14-16 and eliminates the need to secure an additional area for fixing optical sheets 14-16, which contributes to a narrower frame.

[0024] In addition, at two positions symmetrical with respect to the approximate center of the upper side wall 2b of the bottom frame 2 in the figure, a recess 2e into which a part of the elastic member 6 (FIG. 2) fits is provided on the bottom 2a adjacent to the side wall 2b. In addition, at positions on the lower side wall 2b in the figure that correspond approximately to the upper recess 2e, a plurality of legs 2f protruding from the inside of the side wall 2b in the light guide direction are provided. This makes it possible to prevent the light guide plate 13 from rotating like a seesaw with the pillar 2c as a fulcrum. Note that the legs 2f do not have to be at positions corresponding to the upper recess 2e.

[0025] Further, near the foot 2f, there are provided a substantially rectangular recess 2g for accommodating a connecting portion 11b of the substrate 11, which will be described later, and a substantially rectangular hole 2h through which a connecting portion 11d drawn out from the connecting portion 11b is inserted. Note that, although the illustration shows a case in which the foot 2f is provided on the bottom frame 2 side, the foot may be provided so as to protrude from the light guide plate 13 side toward the side wall 2b of the bottom frame 2.

[0026] Fig. 4 is an external perspective view of the elastic member 6. In Fig. 4, the elastic member 6 is made of molded rubber or the like, and has a substantially rectangular flat portion 6a and a substantially rectangular bent portion 6b rising at a right angle from one side of the flat portion 6a. The flat portion 6a is disposed between the main surface on the non-emission side of the light guide plate 13 and the bottom portion 2a of the bottom frame 2, and the bent portion 6b is disposed between the edge on the non-light entrance side of the light guide plate 13 and the side wall 2b of the bottom frame 2.

[0027] Fig. 5 is a perspective view showing a state in which the light guide plate 13 is supported by the pillars 2c, the elastic members 6, and the legs 2f. In Fig. 5, the portion enclosed by the large dashed circle is a partially enlarged view of the portion enclosed by the small dashed circle connected by the dashed line, and when no unique coordinate axis is shown, the coordinate axis is the same as that of the basic perspective view, and when a unique coordinate axis is shown, the view is taken from a different angle along that coordinate axis.

[0028] In FIG. 5, the groove 13c of the light guide plate 13 is engaged with the pillar 2c at the approximate center of the light entrance side of the bottom frame 2. The non-light entrance side of the light guide plate 13 is supported by pressing the side surface with the elastic member 6. This allows the light guide plate 13 to be stably supported by three points, the pillar 2c and the elastic member 6, and even if the side of the light entrance side is long, the generation of rattle noise can be effectively prevented by supporting the light guide plate 13 with the elastic member 6. Note that when the side of the light entrance side of the light guide plate 13 is long, the clearance in the long side direction is large and it is difficult to absorb the expansion and contraction with the elastic member, but the movement of the light guide plate 13 in the long side direction is restricted by the pillar 2c, and the elastic member 6 only needs to restrict the movement in the light guide direction where the clearance is small, so that the light guide plate 13 can be stably supported. In addition, since the elastic member 6 is sandwiched by the light guide plate 13, the elastic member 6 is prevented from popping out, and the light guide plate 13 can be stably supported.

[0029] Furthermore, at a position on the light incident side of the bottom frame 2 opposite the elastic member 6, the foot 2f abuts against and supports the light incident side surface 13b of the light guide plate 13. This makes it possible to prevent the light guide plate 13 from rotating like a seesaw with the pillar 2c as a fulcrum.

[0030] Fig. 6 is a diagram showing an example of the positional relationship between the groove 13c of the light guide plate 13, the pillar 2c of the bottom frame 2, and the light emitted from the light source 12. In Fig. 6, the depth of the groove 13c of the light guide plate 13 in the light guide direction from the light incident side surface 13b is set to a length that does not interfere with the edgemost light L1 emitted from the center of the light source 12 adjacent to the groove 13c. This makes it possible to reduce the effect of the groove 13c of the light guide plate 13 on the optical characteristics.

[0031] Moreover, pillar 2c has a generally rectangular shape with no corners on the light guide plate 13 side in plan view, and groove 13c has a generally rectangular shape with no corners on the back side in plan view. This allows smooth engagement between pillar 2c and groove 13c, and the presence of a linear contact portion allows for stable support.

[0032] Fig. 7 is an end view showing another example of the configuration of the elastic member 6 in the embodiment. In Fig. 7, the elastic member 6 such as a sheet rubber is fixed to the inside of the side wall of the bottom frame 2 with double-sided tape 20, and the non-fixed side of the elastic member 6 presses against the non-light-entering side of the light guide plate 13. Since the elastic member 6 presses in the short direction of the light guide plate 13, the clearance is not excessive even in the case of a horizontally elongated planar lighting device 1, and expansion and contraction of the light guide plate 13 due to temperature changes can be absorbed.

[0033] FIG. 8 is an end view showing another example of the configuration of the elastic member 6 in the embodiment. In FIG. 8, the elastic member 6 is made of synthetic rubber or the like and has a substantially rectangular parallelepiped main body 6c, a recessed portion 6d provided in the middle of the side surface of the main body 6c on the non-pressing side, and a protruding portion 6e provided on one side surface of the main body 6c on the pressing side. The protruding portion 6e engages with a recessed portion 2j provided on the side wall of the bottom frame 2. Since it is difficult to attach synthetic rubber with double-sided tape, the engagement between the protruding portion 6e and the recessed portion 2j prevents the elastic member 6 from popping out. The surface of the elastic member 6 opposite to the surface on which the protruding portion 6e is provided presses the side surface of the light guide plate 13 on the non-light-entering side. This prevents the elastic member from popping out and allows the light guide plate 13 to be stably supported.

[0034] Fig. 9 is an end view showing another example of the configuration of the elastic member 6 in the embodiment. In Fig. 9, the position where the flesh relief 6d of the elastic member 6 in Fig. 8 is provided is different. In Fig. 8, the flesh relief 6d is provided midway on the non-pressing side surface of the main body 6c, but in Fig. 9, the flesh relief 6d is provided from approximately the center on the light guide plate 13 side of the non-pressing side surface of the main body 6c to the end. The effect of the elastic member 6 in Fig. 9 is the same as that in Fig. 8.

[0035] Fig. 10 is a perspective view showing an example of fixing the optical sheet 16 by the pin 2d. In Fig. 10, a hole 16b provided on the light-entering side of the main surface 16a of the optical sheet 16 is engaged with a pin 2d protruding from the bottom frame 2. Note that a lug 16c is provided on the outside of the hole 16b of the optical sheet 16, and is adapted to engage with a recess 2i provided in the side wall 2b of the bottom frame 2.

[0036] Also, the end of the light incident side of the optical sheet 16 is provided facing the substrate 11 on which the light source 12 is arranged with a minimum clearance therebetween. As a result, the end of the light incident side of the optical sheet 16 may come into contact with the substrate 11, but will not come into direct contact with the bottom frame 2, and the generation of rattle noise can be suppressed. This is because the substrate 11 acts as a buffer material. The structure for fixing the optical sheet 16 described above is the same for the optical sheets 15 and 14 arranged on the back side of the optical sheet 16.

[0037] Fig. 11 is a perspective view showing a configuration example of a substrate 11 on which a light source 12 is arranged. In Fig. 11, the portion surrounded by a large dashed circle is a partially enlarged view of the portion surrounded by small dashed circles connected by dashed lines, and is a view seen from the same angle as the coordinate axes of the basic perspective view.

[0038] In Fig. 11, two sets of substrate 11 on which a plurality of light sources 12 are arranged are provided on the left and right in the longitudinal direction. Substrate 11 on which a plurality of light sources 12 are arranged is belt-shaped, and at portion P2f where leg 2f (Fig. 5) is provided, belt-shaped light source mounting portion 11a and light source mounting portion 11c are arranged to bypass leg 2f by connecting portion 11b. Connecting portion 11b is formed integrally with light source mounting portion 11a, and is bent at a right angle to form connecting portion 11b. Furthermore, one end of connecting portion 11b is bent and drawn out as connecting portion 11d.

[0039] The substrate 11 is fixed to the inside of the side wall 2b on the light-entering side of the bottom frame 2, and the connecting portion 11b is fixed to the bottom portion 2a of the bottom frame 2. The back surface of the connecting portion 11b is fixed to the inside of the bottom portion 2a of the bottom frame 2 with double-sided tape 10. This makes it possible to prevent the substrate 11 from being pressed by the feet 2f, and to prevent the substrate 11 from peeling off, etc. Also, the feet 2f can be bypassed without increasing the thickness.

[0040] Fig. 12 is a perspective view showing an example of the configuration of double-sided tapes 7 and 8 that fix a light guide plate 13 at the center of the long side on the light incident side. In Fig. 12, the part surrounded by a large dashed circle is a partially enlarged view of the part surrounded by small dashed circles connected by dashed lines, and is a view seen from the same angle as the coordinate axes of the basic perspective view.

[0041] 12, in a predetermined range approximately at the center of the longitudinal direction of the light-entering side, the end of the light-entering side of the main surface of the non-emitting side of the light guide plate 13 is fixed to the bottom 2a of the bottom frame 2 by a strip-shaped double-sided tape 7 and double-sided tape 8 arranged in a scattered island pattern between a plurality of light sources 12 on the substrate 11. This allows the optical axis in the thickness direction of the light-entering side surface 13b of the light guide plate 13 and the light source 12 to be accurately positioned, and prevents the light guide plate 13 from cracking due to the engagement between the groove 13c of the light guide plate 13 and the pillar 2c of the bottom frame 2. Note that by limiting the range fixed by the double-sided tapes 7 and 8 to a predetermined range approximately at the center of the longitudinal direction of the light-entering side, the double-sided tapes 7 and 8 do not peel off due to expansion and contraction of the light guide plate 13 caused by temperature changes.

[0042] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0043] As described above, the surface illumination device according to the embodiment includes a light guide plate that receives light from the light-entering side, a plurality of light sources that irradiate the light-entering side of the light guide plate, an elastic member that presses and supports the light guide plate, and a bottom frame that houses the light guide plate, the plurality of light sources, and the elastic member, the bottom frame having a pillar that protrudes in the thickness direction at a position facing the approximate center of the longitudinal direction of the light-entering side of the light guide plate, the light guide plate having a groove that engages with the pillar at the approximate center of the longitudinal direction of the light-entering side, and the elastic member pressing the edge of the non-light-entering side of the light guide plate to the light-entering side. As a result, even if the edge of the light-entering side is long, the generation of rattle noise can be effectively prevented by supporting the light guide plate with the elastic member.

[0044] The pillars are connected to the side wall of the bottom frame on the light-entering side and protrude from the bottom of the bottom frame in the thickness direction, thereby increasing the strength of the pillars and enabling them to stably support the light guide plate.

[0045] In addition, the pillars are generally rectangular in shape with no corners on the light guide plate side in plan view, and the grooves are generally rectangular in shape with no corners on the rear side in plan view, which allows smooth engagement between the pillars and the grooves, and the linear contact portions provide stable support.

[0046] In addition, the depth of the groove in the light guide direction from the light-entering side surface of the light guide plate is set to a length that does not interfere with the light emitted from the center of the light source adjacent to the groove, thereby reducing the effect of the groove in the light guide plate on the optical characteristics.

[0047] In addition, the elastic member is disposed between the side of the light guide plate on the non-light-entering side and the side wall of the bottom frame. This allows the light guide plate to be stably supported. When the side of the light guide plate on the light-entering side is long, the clearance in the long side direction is large and it is difficult for the elastic member to absorb the expansion and contraction, but the movement of the light guide plate in the long side direction is restricted by the pillar, and the elastic member only needs to restrict the movement in the light guide direction where the clearance is small, so the light guide plate can be stably supported.

[0048] In addition, two elastic members are disposed at positions symmetrical with respect to approximately the center of the side of the light guide plate on the non-light-entering side, thereby making it possible to stably support the light guide plate at three points, namely the pillars and the elastic members.

[0049] The elastic member is made of molded rubber and has a substantially rectangular flat portion and a substantially rectangular bent portion rising at a right angle from one side of the flat portion, the flat portion being disposed between the main surface of the non-light-exiting side of the light guide plate and the bottom of the bottom frame, and the bent portion being disposed between the side of the non-light-entering side of the light guide plate and the side wall of the bottom frame. This prevents the elastic member from popping out and enables the light guide plate to be stably supported.

[0050] The bottom frame has a recessed portion provided on a side surface of the main body on the non-pressing side and a protruding portion provided on one side surface of the main body on the pressing side, and the protruding portion engages with a recessed portion provided on a side wall of the bottom frame, and the surface opposite to the protruding portion presses the non-light-entering side of the light guide plate. This prevents the elastic member from popping out and enables the light guide plate to be stably supported.

[0051] In addition, a plurality of legs are provided that protrude from the side wall of the bottom frame that faces the light-entering side of the light guide plate toward the light guide plate, thereby making it possible to prevent the light guide plate from rotating like a seesaw with the pillars as a fulcrum.

[0052] In addition, the light guide plate has a plurality of legs protruding from the light incident side toward the side wall of the bottom frame, which makes it possible to prevent the light guide plate from rotating like a seesaw with the pillars as a fulcrum.

[0053] In addition, the substrate on which the multiple light sources are arranged is strip-shaped, and the legs are bypassed by connecting parts at the portions where the legs are provided, which makes it possible to prevent the substrate from being pressed by the legs and to prevent the substrate from peeling off.

[0054] In addition, the substrate is fixed to the inside of the side wall on the light-entering side of the bottom frame, and the connecting portion is fixed to the bottom of the bottom frame, which allows the foot to be bypassed without increasing the thickness.

[0055] In addition, a pin is provided protruding from the pillar in the light output direction, and a hole provided on the light input side of the optical sheet engages with the pin. This makes it easy to fix the optical sheet and eliminates the need to secure another area for fixing the optical sheet, which contributes to a narrower frame.

[0056] In addition, the end of the light-entering side of the optical sheet is disposed opposite the substrate on which the light source is disposed with a minimum clearance between them. This allows the optical sheet to come into contact with the substrate but not directly with the bottom frame, thereby suppressing the generation of rattle noise.

[0057] In addition, the light-entering side end of the non-emission side main surface of the light guide plate is fixed to the bottom of the bottom frame by double-sided tape arranged in a scattered island pattern between the multiple light sources in a predetermined range approximately at the center of the longitudinal direction of the light-entering side surface. This allows the optical axis of the light-entering side surface of the light guide plate and the light source in the thickness direction to be accurately positioned, and prevents cracks from occurring in the light guide plate due to the engagement between the grooves of the light guide plate and the pillars of the bottom frame.

[0058] Furthermore, the present invention is not limited to the above-mentioned embodiment. The present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment, and various modifications are possible. [Explanation of symbols]

[0059] REFERENCE SIGNS LIST 1 Planar lighting device, 2 Bottom frame, 2c Pillar, 2d Pin, 2f Foot, 3 Reflector, 4 Double-sided tape, 5 Spacer, 6 Elastic member, 7, 8, 9, 10 Double-sided tape, 11 Substrate, 11b Connection portion, 12 Light source, 13 Light guide plate, 14, 15, 16 Optical sheet, 17 Spacer, 18 Double-sided tape, 19 Top frame

Claims

1. a light guide plate into which light enters from a light-entering side surface that is a side surface in the longitudinal direction; A plurality of light sources that irradiate light onto a light-entering side surface of the light guide plate; an elastic member that presses and supports the light guide plate; a bottom frame that accommodates the light guide plate, the light sources, and the elastic member; Equipped with the bottom frame has a pillar protruding in a thickness direction only at a position facing substantially the center in a longitudinal direction of the light-entering side surface of the light guide plate, the light guide plate has a groove that engages with the pillar at approximately the center in the longitudinal direction of the light incident side surface, The elastic member presses the non-light-entering side edge of the light guide plate toward the light-entering side. Surface lighting device.

2. A light guide plate into which light enters from a light-entering side; A plurality of light sources that irradiate light onto a light-entering side surface of the light guide plate; an elastic member that presses and supports the light guide plate; a bottom frame that accommodates the light guide plate, the light sources, and the elastic member; Equipped with the bottom frame has a pillar protruding in a thickness direction at a position facing approximately the center in a longitudinal direction of the light-entering side surface of the light guide plate, the light guide plate has a groove that engages with the pillar at approximately the center in the longitudinal direction of the light incident side surface, the elastic member presses a position of the non-light-entering side of the light guide plate, which is different from a corner of the light guide plate, toward the light-entering side; the elastic member presses both sides of the non-light-entering side of the light guide plate, the sides sandwiching a position of the non-light-entering side facing the pillar, toward the light-entering side; Surface lighting device.

3. A light guide plate into which light enters from a light-entering side; A plurality of light sources that irradiate light onto a light-entering side surface of the light guide plate; an elastic member that presses and supports the light guide plate; a bottom frame that accommodates the light guide plate, the light sources, and the elastic member; a plurality of legs protruding from a side wall of the bottom frame facing a light-entering side edge of the light guide plate toward the light guide plate; Equipped with the bottom frame has a pillar protruding in a thickness direction at a position facing approximately the center in a longitudinal direction of the light-entering side surface of the light guide plate, the light guide plate has a groove that engages with the pillar at approximately the center in the longitudinal direction of the light incident side surface, The elastic member presses the non-light-entering side of the light guide plate toward the light-entering side, The substrate on which the plurality of light sources are arranged is strip-shaped, and the legs are bypassed by a connecting portion at a portion where the legs are provided. Surface lighting device.

4. A light guide plate into which light enters from a light-entering side; A plurality of light sources that irradiate light onto a light-entering side surface of the light guide plate; an elastic member that presses and supports the light guide plate; a bottom frame that accommodates the light guide plate, the light sources, and the elastic member; Equipped with the bottom frame has a pillar protruding in a thickness direction at a position facing approximately the center in a longitudinal direction of the light-entering side surface of the light guide plate, the light guide plate has a groove that engages with the pillar at approximately the center in the longitudinal direction of the light incident side surface, The elastic member presses the non-light-entering side of the light guide plate toward the light-entering side, a pin protruding from the pillar in the light output direction, and a hole provided on the light input side of the optical sheet engages with the pin; Surface lighting device.

5. A light guide plate into which light enters from a light-entering side; A plurality of light sources that irradiate light onto a light-entering side surface of the light guide plate; an elastic member that presses and supports the light guide plate; a bottom frame that accommodates the light guide plate, the light sources, and the elastic member; Equipped with the bottom frame has a pillar protruding in a thickness direction at a position facing approximately the center in a longitudinal direction of the light-entering side surface of the light guide plate, the light guide plate has a groove that engages with the pillar at approximately the center in the longitudinal direction of the light incident side surface, The elastic member presses the non-light-entering side of the light guide plate toward the light-entering side, The end of the light-entering side of the main surface of the non-emitting side of the light guide plate is fixed to the bottom of the bottom frame by double-sided tape arranged in a scattered island shape between the plurality of light sources in a predetermined range approximately at the center of the longitudinal direction of the light-entering side surface. Surface lighting device.

6. The pillar is connected to a side wall of the bottom frame on the light-entering side and protrudes in a thickness direction from a bottom of the bottom frame.

3. The spread illuminating device according to claim 2.

7. The pillar has a substantially rectangular shape in a plan view with no corners on the light guide plate side, The groove has a substantially rectangular shape with no corners on the rear side in a plan view.

7. The spread illuminating device according to claim 2 or 6.

8. a depth of the groove in a light guiding direction from a light incident side surface of the light guiding plate is set to a length that does not interfere with light emitted from a center portion of the light source adjacent to the groove; 8. A spread illuminating device according to claim 2, 6 or 7.

9. The elastic member is disposed between a non-light-entering side edge of the light guide plate and a side wall of the bottom frame.

9. A spread illuminating device according to claim 2, wherein the light source is a light source.

10. The elastic members are arranged in two positions symmetrically with respect to approximately the center of the side of the light guide plate on the non-light-entering side.

10. The spread illuminating device according to claim 2, wherein the light source is a light source.

11. The elastic member is made of molded rubber and has a substantially rectangular flat portion and a substantially rectangular bent portion rising at a right angle from one side of the flat portion, the flat portion is disposed between a main surface of the light guide plate on a non-light-emitting side and a bottom portion of the bottom frame, and the bent portion is disposed between an edge of the light guide plate on a non-light-entering side and a side wall of the bottom frame.

11. A spread illuminating device according to claim 2, wherein the light source is a light source.

12. The elastic member is made of molded rubber and has a substantially rectangular parallelepiped main body, a recessed portion provided on a side surface of the main body on the non-pressing side, and a protruding portion provided on one side surface of the main body on the pressing side, The protrusion engages with a recess provided in a side wall of the bottom frame, The surface opposite to the surface on which the protrusion is provided presses the non-light-entering side surface of the light guide plate.

11. A spread illuminating device according to claim 2, wherein the light source is a light source.

13. The light-entering side surface is a side surface in the longitudinal direction of the light guide plate.

13. A spread illuminating device according to claim 2, wherein the light source is a light source.

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