JP2007299669A - Planar lighting fixture and liquid crystal display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar lighting fixture capable of suppressing deflection of a light guide for uniform emission of illumination light. <P>SOLUTION: The planar lighting fixture comprises a light guide assembly consisting of a linear light source; a light guide equipped with an incidence on which the light emitted from the linear light source is incident and a flat light emitting surface for emitting light; a support member which is arranged on the surface opposite to the light emitting surface of the light guide, and supports the light guide; and a fixing means for fixing the light guide and the support member. It also comprises a case which stores the light guide assembly and supports the outer edge of the light guide. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention has a light guide plate that diffuses light emitted from a light source and emits illumination light from a light exit surface, and is a planar illumination device that illuminates indoors or outdoors, or a liquid crystal display panel, an advertising panel, an advertising tower, The present invention relates to a planar illumination device used as a backlight for a signboard or the like and a liquid crystal display device using the same.

As the liquid crystal display device, a planar illumination device (backlight unit) that irradiates light from the back side of a liquid crystal panel (LCD) and illuminates the liquid crystal panel is used. A planar illumination device includes components such as a light source for illumination, a light guide plate that diffuses light emitted from the light source and irradiates the liquid crystal panel, a prism sheet that uniformizes light emitted from the light guide plate, and a diffusion sheet. Constructed using.
Such a planar illumination device includes a planar light guide plate and a planar illumination device having a linear light source arranged on its side surface, a groove on the surface opposite to the surface from which light is emitted in a plate shape. And a planar lighting device having a configuration in which a linear light source is disposed in the groove.

  As a light guide plate in which a groove is formed on the surface opposite to the surface from which light is emitted, Patent Document 1 discloses a rectangular light emitting surface and a thick wall portion which is parallel to one side and located at a substantially rectangular central portion. And a thin end portion formed in parallel to the thick portion, and a parallel groove for accommodating the rod-shaped light source are formed in the center of the thick portion in parallel with the one side, The axis of the rod-shaped light source is included on both sides and is symmetric with respect to a plane perpendicular to the rectangular light exit surface, and the wall is directed from the thick portion toward the thin end portion on both sides in a direction perpendicular to the one side. A transparent light guide plate having a slanted back surface portion that has a reduced thickness and forms a slanted back surface, and is a rod-shaped housing that is housed in the parallel groove in a first portion corresponding to the parallel groove of the rectangular light exit surface. The peak value of illuminance or luminance formed by the light emitted from the light source is compatible with the inclined back surface. A center perpendicular to the rectangular light exit surface of the parallel groove in the cross-sectional shape of the parallel groove in the orthogonal direction according to a ratio to the average value of illuminance or luminance formed by the exit light in the second portion The light guide plate is characterized in that the tip of the parallel groove is thinned symmetrically toward the rectangular light exit surface with respect to the line.

  The light guide plate having the shape described in Patent Document 1 can reduce the thickness and weight of the light guide plate itself, and can emit more uniform, less uneven, and higher brightness illumination light from its light exit surface. It is stated that it can be done.

Japanese Patent Laid-Open No. 2005-23497

The light guide plate used in such a planar illumination device has its four outer edges fixed by a frame. Here, for example, when a plurality of light guide plates described in Patent Document 1 are connected and the light guide plate itself is enlarged in the case of a flat light guide plate and the light guide plate is enlarged, the influence of gravity, external force, heat, etc. Therefore, even if the outer edge of the light guide plate is fixed, the light guide plate may bend.
When the light guide plate bends, the light exit surface may be distorted, and the light guide plate may be separated from the reflector disposed on the surface opposite to the light exit surface. As described above, when the light exit surface is distorted or the reflector is separated from the light guide plate, there is a problem that unevenness in luminance occurs in the light emitted from the light exit surface.
In particular, when the planar illumination device is used as an illumination device for indoor illumination arranged on the ceiling, the light exit surface is arranged downward, so that the light guide plate is more easily bent due to the influence of gravity. It becomes a problem.

Further, the light guide plate is warped due to the influence of heat generated from the light source. The warp generated in the light guide plate increases as the light guide plate itself increases in size. As described above, when the warpage of the light guide plate is increased, luminance unevenness occurs, which is a problem. In addition, there is a problem that even if the flat shape without warping is produced during manufacturing, the light guide plate is warped due to heat generated from the light source or moisture absorption during use.
In particular, the light guide plate in which a plurality of grooves is formed as disclosed in Patent Document 1 houses a light source serving as a heat source inside the light guide plate, and thus is greatly affected by the heat generated from the light source, and is more complicated. Because of its shape, large warpage is likely to occur.

  An object of the present invention is to provide a planar illumination device capable of solving the problems based on the above-described conventional technology, suppressing the deflection of the light guide plate, and emitting uniform and uniform illumination light, and a liquid crystal display device using the same. It is to provide.

  Another object of the present invention is to eliminate the problems based on the above prior art, to suppress the warpage of the light guide plate with a simple structure, to be able to increase the size and to emit uniform and high-luminance light. An object of the present invention is to provide a planar illumination device and a liquid crystal display device using the same.

  In order to solve the above-described problems, the present invention provides a light source plate including a linear light source, an incident portion on which light emitted from the linear light source is incident, and a flat light emission surface that emits light, and the light of the light guide plate. A light guide plate assembly disposed on a surface opposite to the exit surface and having a support member for supporting the light guide plate; and a fixing means for fixing the light guide plate to the support member; and housing the light guide plate assembly. The present invention provides a planar illumination device comprising a housing that supports an outer edge of the light guide plate.

Here, it is preferable that a reflection member is disposed on the surface of the support member on the light guide plate side.
Further, it is preferable that the light guide plate has a plurality of parallel grooves formed on a surface opposite to the light exit surface, and the linear light source is disposed in the parallel grooves.
Furthermore, it is preferable that the light guide plate has a shape in which the thickness in the direction perpendicular to the light exit surface decreases as the distance from the parallel grooves increases, and the thickness decreases at the center between adjacent parallel grooves.
The support member is a single plate-like member that covers the entire surface of the light guide plate opposite to the light exit surface, and the light guide plate and the support member warp in the opposite direction. It is preferable.

Moreover, it is preferable that the said fixing means is a fixing member inserted in the said light guide plate and the said supporting member.
Moreover, it is preferable that the fixing members are arranged in a staggered manner in a plane shape parallel to the light emission surface.
Or it is preferable that the said fixing member is arrange | positioned in the grid | lattice point of a grid-like grid | lattice in planar shape parallel to the said light-projection surface.

The fixing member is preferably a screw or a pin.
Furthermore, it is preferable that the fixing member is made of a material having a transparency of 80% or more when the plate thickness is 1 mm.
The fixing member preferably has a refractive index difference within 0.1 of a refractive index of the light guide plate.
Moreover, it is preferable that the said light-guide plate has the said light emission surface arrange | positioned perpendicularly downward.

  In order to solve the above problems, the present invention provides a planar illumination device according to any one of the above, a liquid crystal display panel disposed on a light emission surface side of the planar illumination device, the planar illumination device, and A liquid crystal display device having a drive unit for driving the liquid crystal display panel is provided.

  According to the present invention, by fixing the light guide plate and the support member by the fixing means, it is possible to prevent the light guide plate from warping and deformation such as bending. Thereby, the light which is uniform and does not have uneven brightness can be emitted from the light emission surface.

In addition, even if the light guide plate is warped by the influence of heat or the like, the support member is a single plate-like member having the same size as the light guide plate, and the warp generated in the light guide plate and the support member is in the opposite direction. And the force of the direction which suppresses curvature acts on a light-guide plate from a support member. Thereby, the curvature of a light-guide plate can be suppressed.
Further, by arranging the fixing members in a zigzag pattern in a plane parallel to the light exit surface of the light guide plate, deformation of the light guide plate can be uniformly suppressed, and more uniform and uneven brightness from the light exit surface. Can emit light.

  A planar illumination device according to the present invention and a liquid crystal display device according to the present invention using the same will be described in detail based on embodiments shown in the accompanying drawings.

FIG. 1 is a schematic perspective view showing an embodiment of the planar lighting device according to the present invention and showing an appearance viewed from the light exit surface side. 2A, 2B, 2C, and 2D are a front view, a bottom view, a side view, and a rear view of the planar illumination device shown in FIG. 1, respectively. FIG. 3 is a partial cross-sectional view of an embodiment of the planar lighting device shown in FIG. In addition, in the following figures including these figures, in order to facilitate understanding, they are shown enlarged in the direction of the thickness of the planar lighting device.
As shown in FIGS. 1 and 2A to 2D, the planar illumination device 10 includes a plurality of linear light sources 12 and emits uniform light from a rectangular light exit surface 14a. 14, a housing 16 in which the lighting device main body 14 is housed and a rectangular opening 16a is formed on the light emitting surface 14a side (surface side), and the housing 16 is opposite to the light emitting surface 14a. An inverter storage unit 20 that stores a plurality of inverter units 18 that are attached to the side (rear surface side) and that is used to light each of the plurality of linear light sources 12, and a plurality of inverter units 18 that are stored in the inverter storage unit 20 And a power source 38 (see FIG. 6) for lighting the plurality of linear light sources 12 respectively.

Here, the illuminating device main body 14 is for emitting uniform light from the rectangular light emitting surface 14a. As shown in FIGS. 3, 4 and 5A, basically, A plurality of linear light sources 12 and a rectangular light exit surface 22a are formed on the light exit surface 14a side, and a plurality of parallel grooves 22b for accommodating the plurality of linear light sources 12 are formed on the back side thereof. The light guide plate 22 in which the thinnest portion 22c having the thinnest thickness from the light exit surface 22a toward the back side is formed between the grooves 22b, and the light exit surface 14a having a rectangular shape is disposed on the light exit surface 22a side of the light guide plate 22. And an optical member unit 24 having a rectangular plane, a reflecting member 26 disposed along the back surface 22d of the light guide plate 22, and a support member 28 disposed along the back surface of the reflecting member 26.
4 shows only the part relating to the unit light guide plate 23 having one parallel groove 22b which is one unit constituting the light guide plate 22, but as shown in FIG. In addition, the illuminating device main body 14 is based on the light guide plate 22 including a plurality of unit light guide plates 23, and the optical member unit 24 arranged on the upper portion of the light guide plate 22 is also substantially the same as the light emission surface 22 a of the light guide plate 22. Needless to say, it has a size (area).

The linear light source 12 is disposed in the plurality of parallel grooves 22 b of the light guide plate 22 and is connected to the inverter unit 18. The linear light source 12 used in the present invention is a linear, that is, a thin rod-shaped cold cathode tube (CCFL: see FIG. 6), and is used to illuminate a surface. Here, a cold cathode tube is used as the linear light source 12, but the present invention is not limited to this, and the linear light source 12 may be any rod-shaped light source (linear light source), In addition to the cold cathode tube (CCFL), for example, a normal fluorescent tube, a hot cathode tube (HCFL), an external electrode tube (EEFL), a light emitting diode (LED), a semiconductor laser, or the like can be used. When an LED is used as the linear light source 12, a cylindrical or prismatic transparent light guide having a length equivalent to the parallel groove 22b of the light guide plate 22 is used, and the upper surface of the light guide and An LED light source may be used in which an LED is disposed on the bottom surface, light from the LED is incident from the top and bottom surfaces of the light guide, and is emitted from the side surface of the light guide.
The inverter unit 18 and the power source 38 (see FIG. 6) for turning on and off the plurality of linear light sources 12 will be described later.

The light guide plate 22 includes a plurality of unit light guide plates 23 as shown in FIG.
The unit light guide plate 23 is made of a transparent resin, and as shown in FIG. 5B, a rectangular individual light exit surface 23a, a thick portion 23b parallel to one side thereof, and both sides of the thick portion 23b. A thin end portion 23c formed parallel to one side, and the thickness is reduced from the thick portion 23b toward the thin end portions 23c on both sides in a direction perpendicular to the one side, constituting the back surface 22d of the light guide plate 22; It has an inclined back surface portion 23e that forms a curved inclined surface 23d, and a parallel groove 22b that is formed parallel to one side of the thick portion 23b and that houses the light source 12. That is, the unit light guide plate 23 includes one parallel groove 22b, and has an individual light exit surface 23a having the same length as the light exit surface 14a of the light guide plate 22 in a direction parallel to the parallel groove 22b. .
As the structures and materials of the unit light guide plate 23 and the light guide plate 22, those disclosed in [0036] to [0039] of Japanese Patent Application Laid-Open No. 2005-23497 related to the applicant's application can be applied.

The parallel grooves 22b may have two hyperbolic shapes that intersect each other as shown in the illustrated example. However, any shape having a luminance uniforming effect such as a triangular shape, a U shape, or a parabolic shape may be used. A thing disclosed in [0040] to [0058] of Japanese Patent Application Laid-Open No. 2005-23497 related to the application of the present applicant can be applied.
Further, the inclined surface 23d may be formed of a curved surface as in the illustrated example, or may be a flat surface having a constant inclination angle with respect to the individual light exit surface 23a, or a plurality of inclination angles that gradually change. These curved surfaces and planes need to be parallel to the parallel grooves 22b.
The profile of the cross section of the parallel groove 22b and the inclined surface 23d orthogonal to the parallel groove 22b is not particularly limited, but the luminance uniformity of the illumination light emitted from the individual light emission surface 23a is high, and If there is little decrease in luminance, the present invention is not particularly limited, but the one disclosed in Japanese Patent Application No. 2004-325251 relating to the application of the present applicant can be applied.

The unit light guide plate 23 allows illumination light emitted from the linear light source 12 accommodated in the parallel groove 22b to enter, and is inclined in a direction parallel to the individual light emission surface 23a from the thick portion 23b toward the thin end portion 23c. The illumination light propagated in the back surface portion 23e and the illumination light reflected by the inclined surface 23d and the reflecting member 26 arranged along the inclined surface 23d that forms the back surface are uniformly distributed from the individual light emitting surface 23a. Is emitted as a simple illumination light.
Thus, uniform illumination light is emitted from the light exit surface 22a of the light guide plate 22 to which the plurality of unit light guide plates 23 are connected.
As shown in FIG. 5A, the light guide plate 22 has a structure in which the unit light guide plates 23 adjacent to each other in the direction orthogonal to the parallel groove 22b are connected to each other by the thin end portions 23c. The connecting portion forms the thinnest portion 22 of the light guide plate 22. In this case, it goes without saying that the light emission surfaces 23a of the plurality of unit light guide plates 23 are connected to one another, and the light guide plate 22 forms a uniform light emission surface 22a.

  As shown in FIG. 5A, the light guide plate 22 may be a single light guide plate connector integrally formed with a plurality of unit light guide plates 23 connected, but cost reduction and yield are achieved. In consideration of the improvement in manufacturing and the ease of manufacture, a plurality of integrally formed light guide plate assemblies of unit light guide plates 23 may be connected to form a large-sized light guide plate having a large area of light exit surface 22a. In this case, the light guide plate connector is connected to the thin end portions 23c of the unit light guide plates 23 of the adjacent light guide plate connectors, and is connected in a direction orthogonal to the parallel grooves 22b to increase the size and the light exit surface. 22a may be increased in area, or the end portions orthogonal to the thin-walled end portion 23c of the adjacent light guide plate connector are connected to each other and connected in a direction parallel to the parallel groove 22b to increase the size, and the light exit surface 22a. It is possible to increase the area of the light emitting surface 22a by simultaneously performing these operations and connecting them in a direction parallel to and perpendicular to the parallel grooves 22b. At this time, it is needless to say that the uniform planar light exit surfaces of the plurality of light guide plate coupling bodies are connected to one another, and the light guide plate 22 forms a uniform planar light exit surface 22a. Absent. In this case, the linear light source 12 is preferably a linear light source having the length of the parallel groove 22b of the light guide plate 22 to which the light guide plate connector is connected, and is disposed above the light guide plate 22. The optical member unit 24 preferably has substantially the same size (area) as the light exit surface 22 a of the light guide plate 22.

  The optical member unit 24 makes the uniform illumination light emitted from the light emission surface 22a of the light guide plate 22 more uniform, and emits the illumination light with further improved uniformity from the light emission surface 14a of the illumination device body 14. As shown in FIGS. 3 and 4, a microprism array parallel to the parallel grooves 22b of the light guide plate 22 and forming the light emission surface 14a is formed and emitted from the light emission surface 22a of the light guide plate 22. The prism sheet 24a that improves the brightness by improving the condensing property of the illumination light, the diffusion sheet 24b that diffuses and equalizes the illumination light emitted from the light exit surface 22a of the light guide plate 22, and the light exit surface 22a of the light guide plate 22 Is used to reduce the luminance unevenness of the illumination light emitted from the transparent film 25a, and is arranged on the surface according to the luminance unevenness, and a large number of transmittance adjusting bodies 25b made of a diffuse reflector. And a transmittance adjusting member 24c provided.

The transmittance adjusting member 24c is preferably provided on the side close to the light exit surface 22a of the light guide plate 22, but the arrangement order and number of the prism sheets 24a and the diffusion sheets 24b are not limited, and the optical member The prism sheet 24a, the diffusion sheet 24b, and the transmittance adjusting member 24c used in the unit 24 are not limited to those described above, and illumination light emitted from the light exit surface 22a of the light guide plate 22 can be made more uniform. Any optical member may be used as long as it is one. The prism sheet 24a may be disposed between the light guide plate 22 and the reflecting member 26 on the back surface 22d side, or a prism row may be formed on the back surface 22d of the light guide plate 22 itself.
Regarding optical members used in the optical member unit 24 including the prism sheet 24a, the diffusion sheet 24b, and the transmittance adjusting member 24c, see [0027] to [0028] in Japanese Patent Application Laid-Open No. 2005-23497 related to the application of the present applicant. What is disclosed can be applied.

  In addition to the arrangement of the optical member 24, or in place of the arrangement of the optical member 24, it is preferable to process the light exit surface of the light guide plate 22 so that the light exit surface has a light diffusion effect. Specifically, by forming fine irregularities such as prisms on the light exit surface, making the light exit surface a sand-printed surface, and printing halftone dots on the light exit surface, the light uniformity can be further improved. it can.

The reflecting member 26 used in the illuminating device main body 14 is disposed along the back surface 22 d of the light guide plate 22 and is for improving the utilization efficiency of the illumination light emitted from the linear light source 12. A reflective sheet 26a disposed along the back surface 22d of the light guide plate 22 excluding the parallel grooves 22b on the side where the grooves 22b are formed, reflecting light leaking from the back surface of the light guide plate 22 and entering the light guide plate 22 again; The light guide plate 22 is arranged on the back surface of the linear light source 12 so as to block the parallel grooves 22b of the light guide plate 22 between the adjacent reflection sheets 26a. And a reflector 26b for making the reflected light incident from the side wall surface of 22b.
Here, in the present embodiment, the reflection sheet 26a and the reflector 26b are formed as one sheet-like member, but may be separate members.

  The support member 28 is formed of a resin such as polycarbonate, and is disposed on the surface of the reflection member 26 opposite to the light guide plate 22 side. The portion of the support member 28 that faces the inclined surface 23 d of the light guide plate 22 has a shape along the back surface of the light guide plate 22, and supports the light guide plate 22 from the back surface 22 d side through the reflection member 26. Further, the surface of the support member 28 on the side opposite to the surface on the light guide plate 22 side is a flat surface, and is fixed to the lower housing 30 described later.

Furthermore, as the light guide plate support, a member obtained by inverting the light guide plate can be used.
By using a member obtained by inverting the light guide plate for the light guide plate support, positioning of the light guide plate and the light guide plate support can be facilitated, and the light guide plate support needs to be manufactured as a separate member. The manufacturing cost can be reduced.
Furthermore, by using a defective product that cannot be used as a light guide plate due to scratches on the surface, etc., the manufactured parts can be used efficiently, improving the yield of the product, and manufacturing costs. Can also be lowered.

Next, the fixing member 60 will be described with reference to FIGS. 3B and 3C.
The light guide plate 22 and the reflection member 26 are formed with holes 22e and 26c that communicate with each other in a direction perpendicular to the light exit surface, and the support member 28 is formed with a screw hole 28e in a direction perpendicular to the light exit surface.
The fixing member 60 is a flat (small) screw with a flat head, and is inserted into the holes 22e and 26c and the screw hole 28e from the light guide plate 22 side, and is screwed into the screw hole 28e. Thereby, the light guide plate 22 and the support member 28 are connected and fixed.
The light exit surface 22a side of the hole 22e has a shape along the head of the countersunk screw (fixing member 60), and the fixing member 60 is embedded in the screw hole 22e up to the head of the countersunk screw. Accordingly, a flat light exit surface is constituted by the light exit surface end surface of the fixing member 60 and the light exit surface of the light guide plate.
The illumination device body 14 is basically configured as described above.

  On the other hand, as shown in FIG. 3, the housing 16 accommodates and supports the illuminating device main body 14, and is sandwiched and fixed from the light emitting surface 14a side and the reflecting member 26 side, and the upper surface is open. The lighting device main body 14 is housed and supported from above, and the lower housing 30 that covers the four side surfaces thereof, and the opening 16a on the upper surface that is smaller than the rectangular light emission surface 14a of the lighting device main body 14 are provided. A rectangular opening is formed, the lower surface is opened, and the upper housing 32 is covered from above so as to cover the light guide plate assembly 14 and the lower housing 30 in which the light guide plate assembly 14 is housed, including its four side surfaces. A concave (U-shaped) folding member 34 fitted between the side wall of the lower housing 30 and the side wall of the upper housing 32, and the rear surface 22 d of the light guide plate 22. Is supported via the reflecting member 26, and the lighting device And a light guide plate supporting member 36 also supports the whole body 14. Although not shown in FIG. 3, an inverter storage unit 20 (see FIG. 2) that stores a plurality of inverter units 18 is attached to the back side of the lower housing 30.

Here, as a method for joining the lower housing 30 and the folding member 34, and a method for joining the folding member 34 and the upper housing 32, various known methods such as a method using bolts and nuts, a method using an adhesive, and the like. Can be used.
The upper housing 32 is larger than the lower housing 30 and at least outer wall surfaces at both ends of the lower housing 30 parallel to the parallel grooves 22b of the light guide plate 22 of the illuminating device body 14 or the linear light source 12 housed therein. The folding member 34 needs to be disposed in each gap between the inner wall surface of the upper casing 32 and the upper casing 32 opposed to the lower casing 30 on the four side surfaces of the casing 16. It may be arranged between the side wall of the upper housing 32 and the side wall of the upper housing 32. Moreover, it is preferable to attach the reinforcement member which reinforces the recessed part of the concave folding member 34. FIG.
By disposing the folding member 34 in this way, the rigidity of the housing 16 can be increased, and light can be emitted uniformly and efficiently. On the other hand, the light guide plate 22 is likely to warp due to the presence of the parallel grooves 22b. Even so, it is possible to correct the warp or prevent the light guide plate 22 from warping, and to obtain good optical characteristics without causing uneven brightness. Moreover, the rigidity of the housing | casing 16 can be made higher by attaching the reinforcement member which reinforces the recessed part of the folding | turning member 34, and it can prevent more appropriately that the connection light-guide plate 22 warps. Thereby, better optical characteristics can be obtained.

Note that the housing 16 has a stopper such as an L-shaped metal fitting that joins its four corners, or a rubber between the prism sheet 24a of the lighting device body 14 and the peripheral edge of the opening 16a of the upper housing 30. There may be provided an elastic member made of an elastic material such as a protective member that protects the entire upper surface of the prism sheet 24a of the planar apparatus main body 14.
The housing 16 is basically configured as described above.

Next, driving devices for the plurality of linear light sources 12 housed in the parallel grooves 22b of the light guide plate 22 of the planar device body 14 will be described.
A driving device 37 shown in FIGS. 6A and 6B drives a linear light source 12 such as a plurality of CCFLs, that is, turns on and off, and drives the illumination of the planar lighting device 10. A plurality of inverter units 18 respectively connected to the linear light sources 12 such as a plurality of CCFLs, and a power source 38 to which the plurality of inverter units 18 are connected. FIG. 6B shows a block diagram of the drive unit 37 for lighting the linear light source 12 such as one CCFL in order to show the detailed configuration of the inverter unit 18.
The power source 38 is a DC power source that outputs a DC voltage, for example, a DC voltage of 24V DC. This DC voltage is supplied to each of the plurality of inverter units 18 connected to the power source 38.

  The inverter unit 18 is connected to the drive circuit 18a that generates a primary AC signal having a predetermined frequency of a predetermined voltage (for example, 650 Vp-p) from the DC voltage supplied from the power supply 38, and the linear light source 12, and is connected to the drive circuit. A transformer 18b that boosts the primary AC signal generated in 18a to a high-voltage secondary AC signal (for example, 6500 Vp-p, 1000 to 2400 Vrms) necessary for lighting the linear light source 12 such as CCFL; The tube current detection circuit 18c for detecting the tube current connected to the linear light source 12 such as CCFL and the tube current output from the tube current detection circuit 18c are fed back, and the drive circuit 18a receives the primary AC signal. A voltage-controlled oscillation circuit 18d that oscillates a clock (fundamental wave) having a predetermined frequency for generation according to the fed-back tube current That.

In the present invention, by configuring the drive device 37 of the linear light source 12 in this way, the plurality of linear light sources 12 are lit simultaneously and uniformly efficiently, stably and safely, with uniform brightness. Can emit light.
In the present invention, the plurality of linear light sources 12 are turned on at the same time. However, only a part of them may be turned on by the inverter unit 18 or these may be switched.
The linear light source driving device and the planar illumination device are basically configured as described above.

  Although the planar lighting device 10 of the embodiment described above is provided with the inverter storage portion 20 on the back side of the housing 16 and stores the plurality of inverter units 18, the planar lighting device of the present invention is limited to this. 7, between the lower housing 30 and the upper housing 32 in the periphery of the opening 16 a of the housing 16 on the side orthogonal to the linear light source 12, as in the planar illumination device 11 shown in FIG. 7. A space may be provided to serve as the inverter storage unit 20, and a plurality of inverter units 18 may be stored. By doing so, the back surface of the planar illumination device 11, that is, the back surface of the housing 16 can be flattened, and attachment to a ceiling or a wall surface can be facilitated.

Thus, the planar illumination device of the present invention can prevent the light guide plate from being bent away from the support member by fixing the light guide plate to the support member with the fixing member. Thereby, uniform light can be emitted from the light emission surface of the light guide plate. That is, even when the light emitting surface is arranged to face downward in the vertical direction, the light guide plate can be prevented from bending due to its own weight. For example, a planar illumination device that forms a light emitting surface with a large light guide plate can be Uniform light can be emitted from the light exit surface even when it is arranged on the ceiling with the exit surface facing vertically downward.
Furthermore, by fixing the support member to the lower housing, the support member can be prevented from bending, and the support member can be prevented from bending together with the light guide plate.
The method for fixing the support member to the lower housing is not particularly limited. Even if the support member is fixed to the lower housing using an adhesive, the support member is fixed to the lower housing by a fixing member such as a screw as described above. May be fixed.

Here, the support member 28 is not limited to resin, and various materials such as plastic and metal can be used. However, it is preferable that the support member 28 is made of a material having high rigidity and low specific gravity.
By increasing the rigidity of the support member, the support member can be made difficult to bend, and the light guide plate can be suitably prevented from being bent. Further, by increasing the rigidity of the support member, it is possible to suppress the bending of the light guide plate even when the support member is not fixed to the lower housing.

  In the present embodiment, the surface on the lower housing 30 side (surface opposite to the light guide plate 22 side) is a flat surface. However, the present invention is not limited to this. For example, a plate having a constant thickness is introduced. You may arrange | position along the shape of the back surface of a light plate. That is, a support member having a shape in which the surface on the light guide plate side and the surface on the opposite side are parallel can also be used.

Here, the arrangement position and the number of arrangement of the fixing member 60 are not particularly limited, and may be arranged at an arbitrary position on the light exit surface of the light guide plate. For example, as shown in FIG. However, it is preferable to arrange the light guide plate at a position where the deflection amount of the light guide plate is large.
In addition, as an arrangement pattern of the fixing members on the plane parallel to the light exit surface of the light guide plate, as shown in FIG. 8B, the fixing members 60 are arranged in a staggered manner, specifically, a lattice of lattices. It is preferable that the dots are arranged in a staggered manner (alternately), and as shown in FIG. 8C, the fixing members 60 are arranged at lattice points of a grid-like lattice, that is, the light emission surface of the light guide plate is arranged. It is preferable to arrange the fixing members 60 at all the intersections of the imaginary lines divided by a certain distance in the direction parallel to the one side and the direction perpendicular to the one side.
By arranging the fixing members in a staggered manner, the light emission surface of the light guide plate can be flattened, and by arranging the fixing members at lattice points of a grid-like lattice, the light emission surface of the light guide plate can be made flatter. be able to.

  In addition, in the plane perpendicular to the extending direction of the linear light source, when the distance between the center of the linear light source and the center of the adjacent linear light source is α, the center of the linear light source and the center of the fixing member It is preferable to arrange the fixing member at a position where the distance is α / 4 or more.

In addition, as shown in FIGS. 8B and 8C, when the fixing member 60 is arranged at the lattice points of the checkered lattice or at the lattice points of the checkered lattice, It is preferable that both the interval L1 in the direction parallel to the axial direction of the linear light source and the interval L2 in the direction perpendicular to the adjacent fixing member 60 be 300 mm or less (L1, L2 ≦ 300 mm), that is, in a grid shape It is preferable that the length of one side of the lattice (interval of the lattice) is 300 mm or less.
Further, the distance between the fixing member arranged on the outermost side of the light emitting surface and the end surface of the light emitting surface (L in FIG. 8A, L3, L4 in FIG. 8B and FIG. 8C). ) Is preferably 300 mm or less.
By arranging the fixing member with the distance between the fixing members being 300 mm or less, the deflection of the light guide plate is 0.2 mm or less, and the occurrence of uneven brightness due to the deflection of the light guide plate can be prevented, and the light exit surface of the light guide plate Can emit uniform light. Furthermore, the bending of the light guide plate can be further suppressed by setting the distance between the fixing member disposed on the outermost side of the light emission surface and the end surface of the light emission surface to 300 mm or less.

Hereinafter, the fixing member will be described in more detail with specific examples.
First, for comparison, a planar lighting device was manufactured in which only the outer edge of the light guide plate was supported by the housing and no fixing member was disposed. Here, as for the light guide plate, 21 unit light guide plates having a length of 28 mm in the direction parallel to the parallel grooves are connected, and a shape that becomes a square light emitting surface with a length of one side of 588 mm has an elastic modulus of 3300 Mpa, It was made of an acrylic resin having a Poisson's ratio of 0.42 and a specific gravity of 1.20.

The produced planar illumination device was arranged such that the light exit surface of the light guide plate was vertically downward, and the deformation amount of the light exit surface was measured.
FIG. 9A schematically shows the deformation amount of the light exit surface of the light guide plate measured in FIG. In FIG. 9A, the deformation is emphasized more than the actual deformation amount in order to easily show the state of the deformation.
As shown in FIG. 9 (a), the light guide plate in which only the outer edge is supported is the center of the light emitting surface where the deformation amount of the light emitting surface increases, that is, the deflection becomes larger from the outer edge toward the center. The amount of deformation at 1.3 mm was 1.3 mm.

Next, as shown in FIG. 8A, a fixing member is arranged at the center of the light exit surface of the light guide plate, that is, a fixing member is arranged at a position where L = 294 mm, and the light guide plate is fixed to the support member. A planar lighting device similar to the above was produced except that. The produced planar illumination device was placed so that the light exit surface of the light guide plate was vertically downward, and the amount of deformation of the light exit surface was measured.
FIG. 9B schematically shows the deformation amount of the light exit surface of the light guide plate measured. Note that FIG. 9B also shows the deformation more emphasized than the actual deformation amount in order to easily show the deformation amount.
As shown in FIG. 9B, the deformation of the center of the light emitting surface can be suppressed by arranging the fixing member at the center of the light emitting surface and fixing the light guide plate to the support member. Moreover, the maximum value of the deformation amount of the light exit surface of this example was 0.17 mm.
Thus, by fixing the light guide plate to the support member by the fixing member, it is possible to suppress the deflection of the light guide plate.

Next, as another embodiment, 35 unit light guide plates having a length of 28 mm in the direction parallel to the parallel grooves are connected to form a square light emission surface with a side length of 980 mm, and an elastic coefficient. A light guide plate made of acrylic resin having 3300 MPa, Poisson's ratio 0.42, and specific gravity 1.20 was produced.
Similar to the above, for comparison, only the outer edge of the manufactured light guide plate is supported by the casing, and a planar illumination device is prepared in which no fixing member is disposed, and the light emission surface is deformed in the same manner as described above. The amount was measured.

FIG. 10A schematically shows the deformation amount of the light exit surface of the light guide plate measured. Note that FIG. 10A also shows the deformation more emphasized than the actual deformation amount in order to easily show the deformation amount.
As shown in FIG. 10 (a), the light guide plate in which only the outer edge is supported is the center of the light emitting surface where the deformation amount, that is, the deflection of the light emitting surface increases toward the center from the outer edge, and the deformation amount becomes the largest. The deformation amount at 7.4 mm was 7.4 mm.

Next, as shown in FIG. 8 (b), the center of the light exit surface of the light guide plate and four corners of a square whose one side is 600 mm, each side is parallel to the light exit surface and the center of the light guide plate is the center. A planar illumination device similar to the above was prepared except that the fixing members were arranged at the five locations and the light guide plate was fixed to the support member. That is, the fixing member is located at one center of the light exit surface of the light guide plate, a line passing through the center of the light exit surface and parallel to one side of the light exit surface, and passing through the center of the light exit surface to the one side of the light exit surface. On the basis of the vertical lines, the four lines are arranged at a total of five places, which are the intersections of the four lines separated by 300 mm from each line. In other words, they are arranged in a staggered pattern at lattice points of a lattice-like lattice with an interval of 300 mm. That is, the fixing members 60 are arranged in a staggered manner at five points including the center of the light exit surface among the lattice points of the lattice where the interval is L1 = L2 = 300 mm and L3 = L4 = 190 mm.
The produced planar illumination device was placed so that the light exit surface of the light guide plate was vertically downward, and the amount of deformation of the light exit surface was measured.
FIG. 10B schematically shows the deformation amount of the light exit surface of the light guide plate measured. FIG. 10B also shows the deformation more emphasized than the actual deformation amount in order to easily show the deformation amount.
As shown in FIG. 10B, the deformation of the center of the light emission surface can be suppressed by arranging the fixing member at the center of the light emission surface and fixing the light guide plate to the support member. Moreover, the maximum value of the deformation amount of the light emitting surface of the present example was 0.19 mm.

Thus, by fixing the light guide plate to the support member by the fixing member, it is possible to suppress the deflection of the light guide plate.
Further, by arranging the fixing members at intervals of 300 mm, the deflection of the light guide plate can be suppressed to 0.2 mm or less.
From the above, the effects of the present invention are clear.

Moreover, it is preferable that the fixing member has a surface having a color with a low light absorption rate such as white, and the transparency when a transparent material such as a transparent resin, specifically, a plate shape with a plate thickness of 1 mm is used. It is more preferable to use a member made of a material that becomes 80% or more. By making the surface of the fixing member a color having a low light absorption rate, light can be efficiently reflected. In addition, by making the fixing member transparent, it is possible to transmit light and use the light efficiently, and it is possible to prevent uneven brightness from occurring by reflecting the light from the fixing member, and the light emission surface Can emit uniform light.
When the light guide plate and the support member are fixed from the support member side using the fixing member as in the present embodiment, the surface is made of a fixing member having a low light absorption rate or a transparent material. A fixing member can be used suitably. Further, when the light guide plate and the support member are fixed from the light guide plate side using the fixing member as in the present embodiment, since a part of the fixing member is exposed to the light emitting surface, the transparent resin or the like is transparent. It is preferable to use a fixing member made of any material.

Furthermore, it is preferable to use a material having a difference in refractive index within 0.1 of the refractive index of the light guide plate for the fixing member. That is, when the refractive index of the light guide plate is n1 and the refractive index of the fixing member is n2, it is preferable that the relationship between n1 and n2 satisfies −0.1 ≦ (n2−n1) ≦ 0.1. . Alternatively, it is preferable to use a material having substantially the same refractive index as that of the light guide plate for the fixing member.
By producing the fixing member with the material having the above-described transmittance, it is possible to prevent occurrence of luminance unevenness in the fixing member portion, and uniform light can be emitted from the light emission surface.

Moreover, in the said embodiment, although the fixing member was set as the flat head screw fixed from the light-guide plate side, this invention is not limited to this. 11A to 11C are schematic cross-sectional views showing other examples of the fixing member of the planar lighting device of the present invention. Here, in FIG. 11 (a)-(c), only one fixing member is shown for description.
As shown in FIG. 11A, screw holes 22f are formed in the light guide plate 22, holes 28f are formed in the support member 28, and screws 60a are screwed into the screw holes 22f of the light guide plate 22 from the support member 28 side. The light plate 22 and the support member 28 may be fixed.
11B, a hole 22g is formed in the light guide plate 22, a screw hole 28g is formed in the support member 28, and a screw 60b is screwed into the screw hole 28g of the support member 22 from the light guide plate 22 side. The light guide plate 22 and the support member 28 may be fixed.
As described above, the screw may be fixed from the light guide plate side or from the support member side, and the screw hole may be halfway through the light guide plate or the support member even if it penetrates the light guide plate and the support member. It is good. Further, both holes formed in the light guide plate and the support member may be screw holes. Moreover, the shape which a part of fixing member protruded from the light-projection surface of the light-guide plate may be sufficient.

Moreover, in FIG.3 (c), FIG.11 (a), and (b), although the light-guide plate and the supporting member were fixed only with the screw, this invention is not limited to this. For example, as shown in FIG. 11 (c), tapered holes 22 h and 28 h are formed in the light guide plate 22 and the support member 28 having taper diameters that decrease from the light exit surface of the light guide plate 22 toward the flat surface of the support member 28. To do. The fixing means 60c includes a taper pin 62a and a screw 62b in which screw holes are formed. The light guide plate 22 and the support member 28 can also be fixed by fitting the taper pin 62a from the light guide plate 22 side and screwing the screw 62b into the screw hole of the taper pin 62a from the support member 28 side.
Of course, the head of the screw 62b has a diameter larger than the minimum diameter of the taper pin 62a. The taper pin 62 is also made of a material having a refractive index of 95% to 110% with respect to the refractive index of the light guide plate, or a material having substantially the same refractive index as that of the light guide plate. Is preferred.
3 (c), 11 (a), and 11 (b), the fixing member is described as a screw. However, in the case of a rivet, the light guide plate and the supporting member can be similarly fixed by various methods. it can.

  Furthermore, it is preferable that the planar illumination device of the present invention supports the outer edge of the light guide plate by a housing as in the present embodiment. By supporting the outer edge of the light guide plate by the housing, it is possible to prevent the outer edge side of the light guide plate from being bent. Thereby, bending of a light guide plate can be prevented, without arrange | positioning a fixing member to the outer edge of a light guide plate.

  In addition, when using a light guide plate having a structure in which a plurality of light guide plate connectors are connected, each light guide plate connector is fixed by a fixing member, so that in addition to the above effects, the planar lighting device is placed vertically or the like. However, it can prevent that each light-guide plate coupling body shifts | deviates, and can fix a light-guide plate stably. Moreover, the light-guide plate coupling body in which an edge part does not contact | connect a housing | casing can also be fixed suitably. Thus, according to the present invention, each light guide plate coupling body can be suitably fixed even when the plurality of light guide plate coupling bodies are simply arranged in parallel without being connected with an adhesive or the like.

Here, when using a light guide plate having a configuration in which a plurality of light guide plate connectors are connected, the end of the light guide plate connector other than the portion serving as the outer edge of the light guide plate, the end adjacent to the other light guide plate connector The part is preferably fixed with a fixing member. By fixing the end portion of the light guide plate assembly with a fixing member, it is possible to further prevent bending of the light guide plate assembly, and to stably fix the light guide plate even when the planar lighting device is placed vertically. Can do.
Further, instead of fixing the end portion of the light guide plate assembly with the fixing member, or in addition to fixing with the fixing member, the opposing side surfaces of the light guide plate assembly may be bonded with an adhesive or the like. preferable. Thus, even if it adhere | attaches with an adhesive agent, it can prevent that the edge part of a light-guide plate coupling body bends, and can fix a light-guide plate stably.
When using a light guide plate in which a plurality of light guide plate connectors are connected in this way, it is preferable to fix the end of the light guide plate connector using a fixing member and / or an adhesive. If the bending can be prevented and the light guide plate can be stably fixed, it is not necessary to fix the end portion of the light guide plate coupling body by the fixing member and / or the adhesive.

  In this embodiment, the reflecting member and the supporting member are separate members, but one member having both functions of the reflecting member and the supporting member can also be used. For example, the reflecting member is provided on the surface of the supporting member. The support member may be made of a material that reflects light.

Moreover, it is preferable that a support member has a curvature in the direction which reversed the curvature of the light-guide plate.
Since the support member warps in a direction repelling the warpage of the light guide plate, a force acts in a direction to suppress the warpage between the light guide plate and the support member, thereby suppressing the warpage of the light guide plate and the support member. it can.

  The light guide plate and the support member preferably have the same length of the light guide plate and the length of the support member in the direction perpendicular to the parallel grooves. By making the length of the light guide plate and the length of the support member the same, the warp of the light guide plate can be more reliably suppressed.

  Furthermore, when the support member has a warp in the direction in which the warp of the light guide plate is reversed, it is preferable that the fixing member is disposed only at a specific position according to the warp of the light guide plate. It is more preferable to arrange in a portion where the amount of warping is large.

12A and 12B are schematic views showing the relationship between the warpage of the light guide plate 22 and the warpage of the support member 28 and the fixing member 60. FIG. Here, in FIGS. 12A and 12B, in order to easily show the warp, the light guide plate 22 shows only the light exit surface 22a, the support member 28 shows only the flat surface 28a, and the fixing member 60 is shown. Shown with an arrow.
As shown in FIG. 12A, when the light guide plate 22 (the light exit surface 22a) and the support member 28 (the flat surface 28a) warp so as to be concave in the center, the light guide plate 22 and the support member It is possible to prevent the light guide plate 22 from being warped by fixing the edge of 28 with the fixing member 60.
In addition, as shown in FIG. 12B, when the light guide plate 22 (the light exit surface 22a) and the support member 28 (the flat surface 28a) are warped so as to protrude in the center, the light guide plate 22 and By fixing the central portion of the support member 28 with the fixing member 60, the light guide plate 22 can be prevented from warping.

  Further, in addition to arranging the fixing member in accordance with the warp of the light guide plate, it is possible to more reliably suppress the warp and the deflection of the light guide plate by arranging the fixing member in a staggered pattern or a lattice shape.

Fig.13 (a) is a schematic side view which shows other embodiment of the planar illuminating device of this invention, FIG.13 (b) is the bb sectional view taken on the line of Fig.13 (a).
The planar lighting device 80 includes a lighting device main body 82, a housing 84, an inverter unit (not shown), and a power source. Here, since the inverter unit and the power source are the same as the inverter unit and the power source of the planar illumination device 10 described above, illustration and detailed description thereof are omitted.

The illumination device main body 82 includes the light source 12, the light guide plate 22, the optical member unit 24, the support member 28, and the fixing member 60.
In the present embodiment, the inclined surface of the light guide plate 22 and the inclined surface of the support member 28 are arranged in contact with each other, and the light guide plate 22 and the support member 28 are fixed by a fixing member 60.
The support member 28 is a sheet metal having an uneven shape along the back surface 22 d of the light guide plate 22, and the surface opposite to the light guide plate 22 also has an uneven shape.
The surface of the support member 28 on the light guide plate 22 side is made of a reflective material, and the support member 18 also has a function as a reflective member.
The light source 12 is disposed in the parallel groove 22 d of the light guide plate 22, and the optical member unit 24 is disposed on the light exit surface 22 a side of the light guide plate 22.

The housing 84 includes a stay 86 and a decorative diffusion plate 88.
The stays 86 are rod-shaped members extending in a direction orthogonal to the parallel grooves of the light guide plate 22, and a plurality of stays 86 are arranged on the flat surface of the support member of the lighting device main body 82 with a predetermined spacing.

The decorative diffusion plate 88 has a box shape with one surface open, and covers the side surface and the light emission surface of the illumination device body 82 from the light emission surface side of the illumination device body 82. The opening of the decorative diffusion plate 88, that is, the surface opposite to the light emitting surface is connected to the stay 86. The lighting device main body 82 is supported and fixed by the stay 86 and the decorative diffusion plate 88 on the light emission surface and the opposite surface.
The decorative diffusion plate 88 has the same function as the diffusion sheet described above, and diffuses the illumination light emitted from the illuminating device main body 82 while making it uniform and emits it.
In this way, in the planar illumination device 80, the light emitted from the illumination device body 82 is emitted through the decorative diffusion plate 88.

By arranging the stay 86 extending in the direction orthogonal to the parallel groove on the flat surface of the support member 28, the strength of the lighting device body 82 can be increased and the light guide plate 22 can be made more difficult to warp.
In addition, since the light guide plate 22 and the support member 28 can be fixed by the fixing member 60 to prevent the light guide plate from being bent and warped, the lighting device body 82 is supported and fixed as a housing 84 for fixing the support member 28. Only the stay 86 that supports the lighting device main body 82 from the flat surface side can be used. Thus, by fixing the light guide plate 22 and the support member 28 with the fixing member 60, the planar illumination device can have a simple configuration.

  Here, in this embodiment, the stay is used as the support means of the lighting device body, but the present invention is not limited to this, and other rod-like members such as pipes can also be used. The strength of the lighting device body can be increased by fixing the lighting device body from the surface on the support member side by the member.

In addition, since the light guide plate can be reliably fixed to the support member, it is preferable to fix the light guide plate to the support member by the fixing member as in the above-described embodiment, but the present invention is not limited to this, and bonding is performed as a fixing means. The light guide plate, the reflection member, and the support member may be fixed with an adhesive using an agent. In the case of fixing with an adhesive, as in the case of fixing with a fixing member, the position to be bonded with an adhesive may be selected according to the warp of the light guide plate.
Moreover, you may fix a light-guide plate to a supporting member using both an adhesive agent and a fixing member as a fixing means.

Hereinafter, more specific usage examples of the planar lighting device of the present invention will be described.
FIG. 14 is a schematic cross-sectional view showing an embodiment in which the planar lighting device of the present invention is used for room lighting.
The planar illumination device 100 is an inverted Fuji-shaped illumination device in which two illumination device bodies are inclined at a predetermined angle, and includes a plurality of linear light sources 12, two illumination device bodies 14, and two housings. It has a body 16, two inverter units 18, a power source 38, and a support body 102.

  The support body 102 has a substantially isosceles trapezoidal shape with a cross section in a direction perpendicular to the bottom surface 102a passing through the center of the bottom surface 102a and having a line perpendicular to the bottom surface 102a as an axis of symmetry, and the bottom surface 102a is fixed to the ceiling. . That is, the support body 102 has the inclined surfaces 102b and 102c inclined by a predetermined angle with respect to the ceiling 102a. Moreover, the inside of the support body 102 is hollow.

One lighting device main body 14 is housed in a housing 16, and the housing 16 is fixed to the inclined surface 102b. Further, the inverter unit 18 is fixed to a surface opposite to the surface on which the housing 16 of the inclined surface 102b is disposed. That is, the housing 16 is fixed to the outer surface of the inclined surface 102b, and the inverter unit 18 is fixed to the inner surface of the inclined surface 102b.
The other lighting device main body 14 and the housing 16 are disposed on the outer surface of the inclined surface 102c in the same manner as the lighting device main body 14 and the housing 16 disposed on the inclined surface 102b.
That is, the two illuminating device main bodies 14 and the two housings 16 are arranged symmetrically with respect to a line passing through the center of the bottom surface 102a and perpendicular to the bottom surface 102a.

  The power source 38 is fixed to a surface on the opposite side of the surface of the fixed portion 102 that is in contact with the ceiling, that is, an inner surface of the bottom surface. The power source 38 is connected to a plurality of inverter units and supplies a direct current.

Next, FIG. 15A is a cross-sectional view in a direction parallel to the axis of the linear light source 16 around the illumination device main body 14 of the planar illumination device 100 shown in FIG. 14, and FIG. 14 is a front view of FIG. In FIG. 15A, the casing 16, the optical member unit 24, and the reflecting member 26 are not shown.
The linear light source 12 includes a plurality of cold cathode tubes 104 arranged in series in parallel grooves of the unit light guide plate. The cold-cathode tube 104 has a U-shape with folded portions at both ends.
The inverter unit 18 includes a plurality of inverters 108, and each inverter 108 is connected to the cold cathode tube 104.

By forming the cold cathode tube 104 in a U shape, only a portion that emits uniform light excluding a portion that does not emit light such as an electrode portion at the end of the cold cathode tube and a portion that emits unstable light is provided on the light guide plate. Can be arranged in parallel grooves.
As a result, it is possible to prevent the occurrence of luminance unevenness at the connection part of the cold cathode tubes 104 arranged in series, and uniform light can be emitted from the linear light source 104.
Cold cathode tubes are limited in the length that can be manufactured according to the diameter due to problems such as strength, but in this way, by using a plurality of cold cathode tubes arranged in series, a cold cathode tube with a small diameter is used. Also, the linear light source can be lengthened. Thereby, it is possible to make the illuminating device main body long in the extending direction of the parallel grooves, that is, the light emitting surface is long and narrow, while preventing the cold cathode tube from being damaged.

  In this way, the planar illumination device 100 in which the two illumination device main bodies 14 whose light emission surfaces are elongated in the extending direction of the parallel grooves are arranged on the inclined surfaces 102b and 102c of the fixed part 102 having the isosceles trapezoidal shape, respectively. It can be used as room lighting in the same manner as an inverted Fuji type lighting device using a hot cathode tube (HCFL).

In addition, by using a cold cathode tube having a long life as a light source, the number of light source replacements can be reduced as compared with a lighting device using a hot cathode tube. Thereby, the cost (labor cost, parts cost) concerning replacement of the light source can be reduced.
Further, by using a cold cathode tube having a smaller amount of mercury and lead than the hot cathode tube as a light source, it is possible to prevent the diffusion of dangerous substances.

  In addition, when arranging a plurality of cold cathode tubes in series, it is possible to prevent uneven brightness at the connecting portion between the cold cathode tubes, so use a U-shaped cold cathode tube as in this embodiment. However, a linear cold cathode tube without a folded portion may be used.

  Further, the present invention is not limited to the reverse Fuji type lighting device, and it can also be used as an embedded lighting device in which a planar lighting device is embedded in a wall or ceiling so that the light emission surface is flush with the wall.

Next, FIG. 16A is a schematic cross-sectional view showing an embodiment in which the planar lighting device of the present invention is used as a signboard, and FIG. 16B is a front view of the planar lighting device, and FIG. ) Is a side view of the planar illumination device.
The planar illumination device 120 includes a plurality of illumination units 122 and an outer frame body 124.

The illumination unit 122 includes a plurality of linear light sources 12, one illumination device body 14, and one inverter unit 18. Since the illumination unit 122 has the same configuration as the illumination device main body 14 and its peripheral portion shown in FIG. 15, the detailed description thereof is omitted.
The plurality of illumination units 122 are arranged in a two-dimensional direction and spaced apart from each other by a predetermined distance so that the light exit surfaces are on the same plane.

The outer frame body 124 is disposed on the outer periphery of the illumination unit 122, and fixes the illumination unit 122 by a fixing means (not shown). The light emitted from the illumination unit 122 is transmitted through the surface of the outer frame body 124 that faces the light emission surface of the illumination unit 122 (light emission surface of the illumination device main body).
An image is formed on the surface through which the light of the outer frame body 124 of the planar illumination device 120 is transmitted, and the light is emitted from the illumination unit 122 to be used as an illumination signboard for displaying an advertisement or the like. Can do.

  Moreover, in this embodiment, although the illumination unit 122 was arrange | positioned spaced apart by predetermined spacing, you may arrange | position an illumination unit without a clearance gap.

  As described above, the planar illumination device and the liquid crystal display device of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the gist of the present invention. Of course.

It is a schematic perspective view which shows the external appearance seen from the light-projection surface side of one Embodiment of the planar illuminating device of this invention. (A), (b), (c), and (d) are the front view of the planar illuminating device shown in FIG. 1, the side view of a longitudinal direction, the side view of a transversal direction, and a rear view, respectively. (A) is the fragmentary sectional view of the edge part of one Embodiment of the planar illuminating device shown in FIG. 1, (b) is a fragmentary sectional view of a center part, (c) is (b). It is the expanded partial sectional view which showed this fixing member. It is a schematic perspective view of the planar illuminating device main body corresponding to one unit light-guide plate used for the planar illuminating device shown in FIG. (A) is a schematic perspective view of the light-guide plate used for the planar illuminating device shown in FIG. 3, (b) shows the cross-sectional shape of one unit light-guide plate of the planar illuminating device main body shown in FIG. FIG. (A) is the wiring diagram of one Embodiment of the drive device of the linear light source used for the planar illuminating device shown in FIG. 2, (b) is the block of the drive device of the linear light source shown to (a). FIG. It is a schematic block diagram which shows other embodiment of the planar illuminating device of this invention. (A)-(c) is a schematic top view which shows an example of the arrangement position of a fixing member, respectively. (A) And (b) is a schematic diagram which shows the shape of the light-projection surface of a light-guide plate, respectively. (A) And (b) is a schematic diagram which shows the shape of the light-projection surface of a light-guide plate, respectively. (A)-(c) is an expanded partial sectional view which shows the other example of a fixing member, respectively. (A) And (b) is a schematic diagram which shows an example of the curvature of the light-guide plate and support member of the illuminating device main body of the planar illuminating device of this invention, respectively. (A) is a schematic side view which shows other embodiment of the planar illuminating device of this invention, (b) is the bb sectional view taken on the line of (a). It is a schematic sectional drawing which shows specific embodiment of the planar illuminating device of this invention. (A) is sectional drawing of the direction parallel to the axis | shaft of the light source around one illuminating device main body of the planar illuminating device shown in FIG. 14, (b) is a front view of an illuminating device main body. (A) It is a schematic sectional drawing which shows specific embodiment of the planar illuminating device of this invention, (b) is a front view of a planar illuminating device, (c) is a side surface of a planar illuminating device. FIG.

Explanation of symbols

10, 11, 100, 120 Planar illumination device 12 Linear light source 14 Illumination device body 14a Light exit surface 16 Housing 16a Opening 18 Inverter unit 18a Drive circuit 18b Transformer 18c Tube current detection circuit 18d Voltage control oscillation circuit 20 Inverter housing Part 22 Light guide plate 22a Light exit surface 22b Parallel groove 22c Thinnest part 22d Back 23 Unit light guide plate 23a Individual light exit surface 23b Thick part 23c Thin end 23d Inclined surface 23e Inclined back part 24 Optical member unit 24a Prism sheet 24b Diffusion film 24c Transmittance adjusting member 25a Transparent sheet 25b Transmittance adjusting body 26 Reflecting member 26a Reflecting film 26b Reflector 30 Lower housing 32 Upper housing 34 Folding member 36 Light guide plate support member 37 Drive device 38 Power supply 102 Support body 104 Cold cathode tube 06 Inverter 122 lighting units 124 outer frame

Claims (13)

A linear light source, a light guide plate including an incident portion on which light emitted from the linear light source is incident and a flat light emission surface that emits light, and disposed on a surface opposite to the light emission surface of the light guide plate; A light guide plate assembly having a support member for supporting the light guide plate, and a fixing means for fixing the light guide plate to the support member;
A planar lighting device comprising: a housing that houses the light guide plate assembly and supports an outer edge of the light guide plate.   The planar illumination device according to claim 1, wherein the support member has a reflection member disposed on a surface on a light guide plate side. The light guide plate is formed with a plurality of parallel grooves parallel to each other on the surface opposite to the light exit surface,
The planar illumination device according to claim 1, wherein the linear light source is disposed in the parallel groove.   4. The planar shape according to claim 3, wherein the light guide plate has a shape in which a thickness in a direction perpendicular to the light exit surface decreases as the distance from the parallel groove increases, and the thickness becomes the smallest at the center between adjacent parallel grooves. Lighting device. The support member is a single plate-like member that covers the entire surface of the light guide plate opposite to the light exit surface,
The planar lighting device according to claim 1, wherein the light guide plate and the support member are warped in a reciprocal direction.   The planar illumination device according to any one of claims 1 to 5, wherein the fixing means is a fixing member inserted into the light guide plate and the support member.   The planar illumination device according to claim 6, wherein the fixing members are arranged in a staggered manner in a planar shape parallel to the light emitting surface.   The planar lighting device according to claim 6, wherein the fixing member is arranged at a lattice point of a grid-like lattice in a planar shape parallel to the light emitting surface.   The planar lighting device according to claim 6, wherein the fixing member is a screw or a pin.   The planar lighting device according to any one of claims 6 to 9, wherein the fixing member is made of a material having a transparency of 80% or more when a plate thickness is 1 mm.   The planar illumination device according to any one of claims 6 to 10, wherein the fixing member has a refractive index difference of 0.1 or less with respect to a refractive index of the light guide plate.   The planar illumination device according to any one of claims 1 to 11, wherein the light guide plate has the light exit surface disposed vertically downward. The surface illumination device according to claim 1,
A liquid crystal display device comprising: a liquid crystal display panel disposed on a light emission surface side of the planar illumination device; and a drive unit for driving the planar illumination device and the liquid crystal display panel.

Images