JP2007213833A - Flat light fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat light fixture, capable of uniformly illuminating the whole surface without an invalid luminous area while keeping a thin structure, and further attaining a large light fixture having no luminance unevenness by connecting two or more thereof. <P>SOLUTION: This flat light fixture 10 comprises a light guide plate 22 diffusing and emitting light emitted from a linear light source 12 through a light emitting face face, a diffusion plate 24 diffusing the illuminating light emitted through the light emitting face 22a of the light guide plate 22, and a reflecting member 28 having a reflecting surface reflecting the light from the linear light source 12. The electrode part of the linear light source 12 having two or more bent parts at each end thereof is disposed on the reverse side to the light reflecting surface of the reflecting member 28. <P>COPYRIGHT: (C)2007,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 lighting device used as a backlight for a signboard or the like.

  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. Similar planar lighting devices are also used for billboards on advertising panel advertising towers.

  As an example of such a planar illumination device, in Patent Document 1, a tubular light source is disposed in a storage portion formed along the peripheral edge of a light guide plate, and light from the tubular light source is emitted from a light incident surface. A surface light source device that is introduced in the surface direction of a light guide plate is disclosed. According to such a surface light source device, the effective light emission area of the device can be expanded.

  In addition, as another example of the planar lighting device, in Patent Document 2, the luminance at the electrode portion when the cold cathode tubes are aligned and connected in the extending direction by bending the end portions of the cold cathode tubes by 90 degrees. A backlight device capable of suppressing unevenness is disclosed.

JP 2000-294024 A JP-A-11-53921

However, in the surface light source device disclosed in Patent Document 1 described above, since the peripheral portion of the surface light source device is provided with a frame, the portion covered with the frame at the peripheral portion of the light guide plate is not an effective light emitting region. Therefore, it cannot be said that the effective light emitting region is sufficiently wide. Moreover, the terminal part of the both ends of a tubular light source will become a no-light area | region. A method of adjusting the length of the light source so that the terminal portion is out of the effective display area is also conceivable, but in this case, since the width of the frame for housing the terminal becomes large, the effective light emitting area is still sufficient. It's not wide.
Furthermore, the backlight device disclosed in Patent Document 2 requires a space for storing the bent portion of the cold cathode fluorescent lamp. In order to secure this space, a method of increasing the thickness of the device or a method of increasing the width of the frame is used. In either method, a thin backlight device having a sufficient effective light emitting area is used. Cannot be realized.

  An object of the present invention is to solve the problems of the prior art, and to provide a planar illumination device that can secure a sufficient effective light emitting area while maintaining a thin configuration. Another object of the present invention is to provide a planar illumination device having a light emitting area with a larger area by connecting a plurality of planar illumination devices.

In order to achieve the above object, a planar illumination device of the present invention includes a linear light source having electrode portions at both ends, a light guide plate that diffuses light emitted from the linear light source and emits the light from a light exit surface. A diffusion plate for diffusing the illumination light emitted from the light exit surface of the light guide plate, and a reflection member having a light reflection surface for reflecting light from the linear light source, the linear light source having an end portion Each has at least one bent portion, and the electrode portion of the linear light source is disposed on the back surface side of the light reflecting surface of the reflecting member.
Also, a linear light source having electrode portions at both ends, a light guide plate that diffuses light emitted from the linear light source and emits it from a light exit surface, and illumination light emitted from the light exit surface of the light guide plate A diffusing plate for diffusing, and a reflecting member having a light reflecting surface for reflecting light from the linear light source, each of the linear light sources having at least one bent portion at an end thereof; A plurality of planar illumination units in which electrode portions of the light source are disposed on the back side of the light reflecting surface of the reflecting member, and the plurality of planar illumination units are connected in the extending direction of the linear light source and adjacent to each other. The side surfaces to be connected are connected.
Here, as the shape of the bent portion of the linear light source, various shapes such as two perpendicular bent portions, one bent portion with a right angle or more, one bent portion formed of an arc, and the like can be used.

  Furthermore, the planar illumination device of the present invention includes a light transmittance adjusting unit disposed on the light exit surface side of the light guide plate, and the light transmittance adjusting unit includes the linear light source of the light guide plate. The light transmittance in the vicinity of the bent portion is lower than the light transmittance in other portions. It is preferable that the light transmittance adjusting means is a sheet-like one disposed on the light exit surface of the light guide plate, or is directly formed on the light exit surface of the light guide plate.

  In the planar illumination device of the present invention, the light guide plate includes a rectangular individual light exit surface and one or more parallel grooves that store the linear light source on a surface opposite to the individual light exit surface. A unit structure whose thickness in the direction perpendicular to the individual light exit surface decreases in the plane perpendicular to the direction in which the parallel grooves extend, and perpendicular to the direction in which the parallel grooves extend. It is preferable to have one or more in a certain direction, diffuse the light incident from the linear light source, and emit the light from the light exit surface.

  Furthermore, it is preferable that the electrode part of the linear light source is disposed in a recess formed by the inclined back surface of the light guide plate unit and the inclined back surface of the adjacent light guide plate unit.

  According to the present invention, by utilizing the gap formed by the uneven surface of the light guide plate, a thin configuration can be maintained, and there is no invalid light emitting region, and the entire surface can be irradiated uniformly. It becomes possible to realize a state lighting device. Furthermore, by connecting a plurality of the planar illumination devices, a large illumination device without uneven brightness can be obtained.

The planar lighting device of the present invention will be described below.
In the following description, a configuration (planar illumination device unit) corresponding to the minimum unit of the planar illumination device according to the present embodiment will be described first, and then a configuration in which this planar illumination device unit is combined will be described. To do.
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 an exploded perspective view of one 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 each member of the planar lighting device.
As shown in FIG. 1 and FIGS. 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 14 a. 14 (planar illumination unit), a housing 16 in which the illumination device main body 14 is housed, and a rectangular opening 16a is formed on the light emission surface 14a side (front surface side), An inverter storage unit 20 that is mounted on the opposite side (rear side) of the light exit surface 14 a and stores a plurality of inverter units 18 that are used to turn on the plurality of linear light sources 12, and is stored in the inverter storage unit 20. And a power source 42 (see FIG. 9) for turning on the plurality of linear light sources 12 respectively.

Here, the illuminating device main body 14 is for emitting uniform light from a rectangular light emitting surface 14a, and as shown in FIGS. 3, 4 (a) and 5, terminals 12a are provided at both ends. And a plurality of linear light sources 12 each having two bent portions 12b and 12c, a rectangular light emission surface 22a on the light emission surface 14a side, and a plurality of linear light sources 12 on the back side. A plurality of parallel grooves 22b are formed, and a thin portion 22c (gap 48 for storing the end portion of the linear light source 12) is formed between the adjacent parallel grooves 22b. The light guide plate 22, the reflection member 28 disposed along the back surface 22 d of the light guide plate 22, and the light guide plate 22, the linear light source 12, and the reflection member 28 are positioned below the reflection member 28. On the holding base 30 and the light guide plate 22 Located in the light guide plate 22, the linear light source 12, reflector member 28, and a diffusion plate 24 for covering the base 30.
Below the base 30, the driving device 40 is installed in a state of being connected to the linear light source 12, and further, a power source 42 is installed in a state of being connected to the driving device 40.
In addition, the illuminating device main body 14 may include an optical member unit (not shown) or the like for making uniform illumination light emitted from the light exit surface 22a of the light guide plate 22 more uniform.

The linear light source 12 is disposed in the plurality of parallel grooves 22 b of the light guide plate 22. Note that the linear light source 12 is arranged with the silicon ring 26 attached thereto, thereby maintaining an appropriate distance between the light guide plate 22 and the reflecting member 28.
Further, the terminals 12 a (electrode portions) at both ends of the linear light source 12 are connected to caps 36 connected to the distal end portions of the wires 34 extending from the driving device 40. Since the cap 36 has a conductor inside, each terminal 12a is connected to the drive device 40 (inverter unit) by connecting the cap 36 and the terminal 12a using a known method such as soldering or crimping. 18) and electrically connected.

The linear light source 12 used in the present invention is a linear, that is, a thin rod-like cold cathode tube (CCFL: see FIG. 9) used for illuminating in a planar shape. The front end of each has a terminal 12a, and further has two bent portions 12b and 12c that are bent at 90 degrees from the terminal 12a toward the center of the linear light source 12. Similarly, the other tip has a terminal 12a ′ and bent portions 12b ′ and 12c ′.
Light having a uniform luminance is emitted from between the bent portion 12c and the bent portion 12c ′ of the linear light source 12. That is, the end of the linear light source 12 where the luminance is not stable and uniform light cannot be emitted is between the terminal 12a and the bent portion 12c, and between the terminal 12a 'and the bent portion 12c'. Uniform light is emitted from between the bent portion 12 c and the bent portion 12 c ′ of the light source 12.
In addition, although a cold cathode tube is used here as the linear light source 12, the present invention is not limited to this, and the linear light source 12 may be any rod light source (linear light source). In addition to the cold cathode tube (CCFL), for example, a light source such as a normal fluorescent tube (hot cathode tube; HCFL) or an external electrode tube (EEFL) can be used.

  It should be noted that the detailed arrangement of the linear light sources 12 (see FIGS. 3, 5, 6A and 6B), the inverter unit 18 for turning on and off the plurality of linear light sources 12, and a power source 42 (see FIG. 9) will be described in detail later.

The light guide plate 22 is composed of 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. 4B, 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 accommodates the linear 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 paragraphs [0036] to [0039] of Japanese Patent Application Laid-Open No. 2005-23497 related to the applicant's application can be applied. .

The parallel groove 22b may have a triangular shape as shown in the figure, but any other shape that has a luminance uniforming effect such as two intersecting hyperbolic shapes, a U shape, and a parabolic shape is also possible. However, what is disclosed in paragraphs [0040] to [0058] of Japanese Patent Application Laid-Open No. 2005-23497 related to the applicant's application 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 perpendicular 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 through the back surface portion 23e and the illumination light reflected by the inclined surface 23d and the reflecting member 28 disposed along the inclined surface 23d and along the inclined surface 23d constituting 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. 4A, the light guide plate 22 has a structure in which unit light guide plates 23 adjacent to each other in the direction orthogonal to the parallel grooves 22b are connected by the thin end portions 23c. The connecting portion forms the thin portion 22 c 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 each other, and the light guide plate 22 forms a uniform light emission surface 22a.
Further, as shown in FIG. 3, the light guide plate 22 has an end surface that forms an angle of 90 degrees with the light emission surface 22 a from both sides of the light emission surface 22 a in a direction orthogonal to the axial direction of the linear light source 12. 22e and 22e 'are formed. That is, the cross section of the light guide plate 22 in the direction perpendicular to the axial direction of the linear light source 12 has a U shape.
Further, in the inclined surface 23d of the light guide plate 22, a portion facing the bent portions 12c to 12b and 12c ′ to 12b ′ of the linear light source 12 (portion facing the recess 28c of the reflecting member 28) is shown in FIG. As shown in FIG. 4 (b), an escape portion 23f for passing the linear light source 12 is provided.

A halftone dot sheet 25 (light transmittance adjusting means) having a halftone dot pattern is disposed on the light exit surface 22 a of the light guide plate 22. The halftone dot sheet 25 is provided with a large number of halftone dots arranged on the surface of the transparent film in accordance with luminance unevenness, and has a uniform halftone dot pattern at the center thereof. In the vicinity of both ends in the extending direction (both end portions A), a halftone dot pattern having a higher density than other portions is provided. Thereby, the brightness | luminance of the emitted light from the light emission surface 22a is adjusted appropriately. This will be described in detail later.
As the halftone dot sheet 25, various known ones such as a halftone dot pattern formed of a color material or the like may be used. Further, in the present invention, as long as the same effect as that of the halftone dot sheet 25 can be realized, the present invention is not limited to the halftone dot sheet 25. For example, the surface of the light guide plate 22 is adjusted to the above-described halftone dot density. Various known methods such as partially roughening (matting) in correspondence may be used.

As shown in FIG. 4A, the light guide plate 22 may be a single light guide plate assembly integrally formed with a plurality of unit light guide plates 23 connected, but the cost reduction and the yield are reduced. 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 connecting body connects the thin end portions 23c of the unit light guide plates 23 of the adjacent light guide plate connecting bodies and connects them in the direction orthogonal to the parallel grooves 22b to increase the size and emit light. The 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 the length direction of the parallel groove 22b to increase the size and emit light. The surface 22a may be increased in area, or these may be performed simultaneously and connected in a direction parallel to and perpendicular to the parallel grooves 22b to further increase the size of the light emission surface 22a. 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 connected to the light guide plate connector.
In addition, the light guide plate 22 of the present embodiment is, as an example, integrally formed with five unit light guide plates 23 connected in a direction orthogonal to the parallel grooves 22b. A linear light source 12 is arranged. In the illuminating device main body 14 shown in FIG. 3, this connected light guide plate 22 is used.

The reflection member 28 is for improving the utilization efficiency of the illumination light emitted from the linear light source 12, has a curved portion 28 a and a flat portion 28 b, and a parallel groove 22 b of the light guide plate 22 is formed. Placed on the side.
The curved portion 28a is disposed along the inclined surface 23d of the light guide plate 22, and the flat portion 28b is disposed on the back surface of the linear light source 12 so as to close the parallel groove 22b.
That is, the reflecting member 28 is disposed so as to block the parallel grooves 22 b of the light guide plate 22, and the linear light source 12 is sandwiched between the reflecting member 28 and the light guide plate 22. Further, the curved portion 28a and the inclined surface 23d are in contact with each other.
Further, the curved portion 28a has concave portions 28c at both ends in the extending direction.
The reflection member 28 reflects light leaking from the back surface of the light guide plate 22 and makes it incident on the light guide plate 22 again. Further, the light is reflected from the lower surface of the linear light source 12, and the reflected light is incident from the side wall surface of the parallel groove 22 b of the light guide plate 22.
In the illustrated example, one reflection member 28 is provided for the light guide plate 22 including a plurality of unit light guide plates 23, but the present invention is not limited to this, and each unit light guide plate 23 has a separate one. A reflective member may be provided.

Here, arrangement | positioning of each member in the illuminating device main body 14 of this embodiment is explained in full detail based on FIG. 5, FIG. 6 (a) and (b).
One linear light source 12 is disposed on the surface of the reflecting member 28 (the convex portion side of the curved portion 28a, the surface facing the light guide plate 22) along each flat portion 28b. The portions from the terminals 12 a to the bent portions 12 b at both ends are accommodated in a gap 48 between the back surface of the reflecting member 28 (the concave portion side of the curved portion 28 a and the surface facing the base 30) and the base 30. The
That is, the portion from the bent portion 12c to the bent portion 12c ′ of the linear light source 12 is accommodated between the parallel groove 22b of the light guide plate 22 and the flat portion 28b of the reflecting member 28, and from the bent portion 12c to the bent portion 12b. This portion is stored across the parallel groove 22b and the back surface side of the reflection member 28 through the recess 28c of the reflection member 28, and the portion from the bent portion 12b to the terminal 12a is stored on the back surface side of the reflection member 28. .

When this state is viewed from the back side of the reflecting member 28, as shown in FIG. 6A, a part between the bent portion 12c and the bent portion 12b of the linear light source 12 passes through the concave portion 28c, and is linear. The tip portion (portion on the terminal 12a side) of the light source 12 from the vicinity of the bent portion 12b is disposed on the back surface of the reflecting member 28. Further, when viewed from the surface side of the reflecting member 28, as shown in FIG. 6B, a portion from the central portion of the linear light source 12 to the bent portion 12 c is disposed on the reflecting member 28, and the linear light source 12. A portion between the bent portion 12c and the bent portion 12b passes through the recess 28c, and the terminal 12a and the bent portion 12b are arranged on the back side of the reflecting member 28.
The portion from the terminal 12a ′ to the bent portion 12c ′ is also arranged in the same manner as the portion from the terminal 12a to the bent portion 12c.
As described above, the light guide plate 22 is disposed on the base 30 so as to cover the reflective member 28 and the linear light source 12 from the surface side of the reflective member 28 along the unevenness of the reflective member 28. Is done.
Note that the shape of the bent portion of the linear light source 12 is not limited to the shape shown in the above embodiment, but a bent portion (see FIG. 8 (a)) and various shapes such as one bent portion having a right angle or more (see FIG. 8B) can be used.

Here, when the linear light source 12 is arranged on the reflecting member 28 and is lit as described above, as shown in FIG. 7, a portion extending from the bent portion 12b of the linear light source 12 toward the bent portion 12c. However, since it is disposed slightly on the surface of the reflecting member 28, the area of the light source when viewed from the light guide plate 22 side is increased, and the luminance near the bent portion 12b is higher than that of the other portions. However, in the portion indicated by the hatched portion A at both ends of the halftone sheet 25, the luminance in the vicinity of the bent portion 12b is decreased in accordance with the luminance of the other portion by increasing the halftone dot density compared to the other portions. Unevenness can be prevented.
In the shaded area A, the halftone dot density may not be uniform as long as the luminance is uniform. Therefore, a method in which the halftone dot density of the halftone sheet 25 is higher than that in other portions only in the vicinity of the bent portion 12b is more preferable.

Similarly to the light guide plate 22, the base 30 forms end faces 30 a and 30 a ′ on both sides in the direction orthogonal to the axial direction of the linear light source 12. That is, the cross section of the base 30 in the direction perpendicular to the axial direction of the linear light source 12 is a U-shape. Further, through holes 32 are formed along the sides of the linear light source of the base 30 at both ends in the axial direction. In the present embodiment, since there are five linear light sources 12, five through holes 32 are provided at both ends.
One end of the wire (wiring) 34 is connected to the driving device 40, passes through the through-hole 32, reaches the gap 48, and the cap 36 that the other end has is within the gap 48 and the terminal 12 a of the linear light source 12. Connected.
Further, a light diffusing plate 24 is disposed on the light emitting surface 22 a side of the light guide plate 22 so as to cover the light emitting surface 22 a and the end surfaces 22 e and 22 e ′ of the light guide plate 22. The diffusion plate 24 has end faces 24 a and 24 a ′ formed on both sides in the direction perpendicular to the axial direction of the linear light source 12, similarly to the light guide plate 22 and the base 30. The cross section in the direction perpendicular to the axial direction of the linear light source 12 is a U-shape.

FIG. 5 shows an arrangement of the diffusion plate 24, the light guide plate 22, the linear light source 12, the reflection member 28, and the base 30 in the lighting device main body 14. Each member arranged in this manner is provided with through holes in the end surfaces 24a and 24a ′ of the diffusion plate 24, the end surfaces 22e and 22e ′ of the light guide plate 22, and the end surfaces 30a and 30a ′ of the base 30, and a bolt 44 and a nut 46 are provided. Are fixed to each other so that they are joined together to form the lighting device main body 14.
In addition to this, various known methods such as a method using an adhesive may be used as a method for joining the members.
At this time, the lower part of the illuminating device main body 14 is a gap, and the driving device 40 can be installed here.
The illumination device body 14 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 illuminating device body 14 will be described.
The drive device 40 shown in FIGS. 9A and 9B drives the linear light source 12 such as a plurality of CCFLs, that is, turns on and off, and drives the illumination of the planar illumination device 10. A plurality of inverter units 18 connected to the linear light sources 12 such as a plurality of CCFLs, and a power source 42 to which the plurality of inverter units 18 are connected. FIG. 9B shows a block diagram of the drive device 40 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 42 is a DC power source that outputs a DC voltage, for example, a DC voltage of DC 24V. This DC voltage is supplied to each of the plurality of inverter units 18 connected to the power source 42.

  The inverter unit 18 is connected to the linear light source 12 and a drive circuit 18a that generates a primary AC signal having a predetermined frequency of a predetermined voltage (for example, 650 Vp-p) from a DC voltage supplied from the power source 42, 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 driving device 40 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.

In the planar illumination device 10 having such an illumination device main body 14, as in the past, the invalid light emitting regions at the terminal portions at both ends of the linear light source are eliminated, and both ends in the axial direction of the linear light source 12 on the light exit surface 14 a. Up to a portion can be made an effective light emitting region. In that case, by accommodating the bent portions 12b and 12c of the linear light source 12 in the gap 48 of the light guide plate 22, a thin configuration can be maintained without requiring an extra space.
Further, by providing a halftone dot sheet 25 and making the halftone dot density at both ends A of the light emission surface 14a of the halftone dot sheet 25 higher than the other portions, the luminance at both ends of the light emission surface 14a can be changed to other values. It is possible to prevent the surface illumination device from becoming higher than the portion and to emit more uniform light.

Further, in the conventional apparatus, the casing is widened so as to cover the invalid light-emitting area generated at the end of the light emitting surface with the casing or the like. However, in the planar lighting device 10 of the present embodiment, the invalid area is ineffective. Since there is no light emitting region, the width of the casing 16 that covers the periphery of the light exit surface 14a can be suppressed to such an extent that the strength of the device is ensured.
Further, the planar lighting device 10 in which the lighting device main body 14 is installed in the housing 16 described above is provided with the inverter storage portion 20 on the back side of the lighting device main body 14 to store a plurality of inverter units 18. However, the planar illumination device of the present invention is not limited to this, and in the peripheral portion of the opening 16a of the casing 16 on the side orthogonal to the linear light source 12, like the planar illumination device 11 shown in FIG. In addition, a space may be provided between the lower housing 50 and the upper housing 52 to form the inverter storage unit 20 and a plurality of inverter units 18 may be stored. This also makes it possible to flatten the back surface of the planar illumination device 11, that is, the back surface of the housing 16, and facilitate attachment to the ceiling or wall surface.
Furthermore, if the intensity | strength as an apparatus is enough, the structure which does not use the housing | casing 16 for the illuminating device main body 14 may be sufficient. In that case, it is preferable that the diffusing plate 24 has four end surfaces so as to cover all four sides perpendicular to the light emitting surface 14a of the lighting device body 14.

As described above, the configuration corresponding to the minimum unit of the planar lighting device 10 according to the present embodiment has been described. However, as described above, the present invention is a configuration in which a plurality of lighting device bodies 14 (planar lighting device units) are combined. Is also extremely effective.
That is, a plurality of lighting device bodies 14 can be connected in the axial direction of the linear light source 12 to form a large planar lighting device.

When the planar lighting device 10 is enlarged, the side surfaces of the plurality of lighting device main bodies 14 may be connected to each other, and the connected lighting device main bodies 14 may be connected to a housing as shown in FIGS. 16 may be installed.
Further, when connecting, a plurality of lighting device main bodies 14 may be connected. However, the diffuser plate 24, the halftone dot sheet 25, and the base 30 are devices when the lighting device main body 14 is connected and enlarged. It is good also as a structure which has a single thing of the magnitude | size equivalent to the whole.
Further, if the strength of the apparatus is sufficient, the housing 16 may not be used.
According to such a configuration, in the illuminating device main body 14 of the present embodiment, since the effective light emitting region extends to both ends in the axial direction of the linear light source 12, luminance unevenness also occurs in the connecting portions of the illuminating device main bodies 14. It is possible to realize a planar illumination device that does not occur and can perform uniform irradiation.

Furthermore, the planar illumination device 10 of the present invention is connected to the illumination device main body 14 of the illustrated example in a direction orthogonal to the axial direction in addition to increasing the size of the linear light source 12 in the axial direction (hereinafter referred to as parallel connection). And it can also be set as a large sized planar illuminating device. Hereinafter, a configuration that can be suitably used for parallel connection will be described.
In the following description, in order to make the description easy to understand, the structure of the illumination device main body 14 constituting the planar illumination device 10 is schematically shown in a form as shown in FIG.
That is, in the following description, the illuminating device main body 14 is connected to the base 30, the reflecting member 28, the power source 42, the linear light source 12 connected to the inverter unit (not shown) via the drive circuit 18a, and the light guide plate 23 ( 22) are stacked in order from the bottom. In FIGS. 11, 12, and 13, the diffusion plate 24, the side surfaces of the light guide plate 22, and the side surfaces of the base 30 are not shown.

  When the illuminating device main body 14 is connected in parallel as it is (see FIG. 13B), the connection portion of the illuminating device main body 14 is indicated by a circle A as shown in FIG. 13A. Such a decrease in luminance occurs. This is influenced by the reflection of light generated on the end surface (inner surface) of the light guide plate of the illuminating device main body 14.

  On the other hand, in one embodiment of the present invention shown in FIG. 11 (b), at least one of the portions that contact each other when the light guide plate 23 (22) of the lighting device body 14 is connected is cut off by a predetermined dimension. It is a dimension. Here, the dimension a in FIG. 11B indicates the arrangement interval of the linear light sources 12 in the basic structure of the light guide plate 23 (22) of the illuminating device body 14. On the other hand, the dimension b indicates the arrangement interval of the linear light sources 12 after truncating the dimension of the end face portion of the light guide plate 23 (22), and the dimension b is shorter than the dimension a.

The amount of trimming of this dimension is performed so as to compensate for the above-described decrease in luminance, as will be described below.
That is, when the dimensions are cut off at the connection portion of the light guide plate 23 (22) of the illuminating device main body 14, when the connection is made after the dimensions are cut down, the connection portion reflects light inside as described above. Even if a decrease in brightness occurs, the brightness is improved enough to make up for it.

Actually, as shown by a circle B in FIG. 11 (b), the dimensions are cut down so that the luminance at the connection portion is slightly higher than the other portions (shown by broken lines), The increase is preferably dispersed by using a diffusion sheet 54 having a diffusivity pattern corresponding to the above-described luminance increase pattern so that the luminance is uniform as a whole.
As the diffusion sheet 54, various known materials such as a halftone dot sheet can be used as in the light guide plate 22 shown in FIG. Further, the surface of the light guide plate 22 may be processed so as to obtain the same effect as the halftone sheet.

According to the configuration shown in FIG. 11B, even when the illuminating device main body 14 is arranged in a direction perpendicular to the axial direction of the preceding light source 12, there is no large luminance unevenness on the light exit surface and a large luminance having a uniform luminance distribution. The planar lighting device can be provided.
Furthermore, in order to make the luminance of the emitted light uniform in the connection portion, other light emitters (linear light source, point light source, etc.) are arranged in the vicinity of the connection portion of the illuminating device main body 14 other than the method described above. Method, a method of increasing the brightness of only the linear light source close to the connection part (by changing the light source shape, increasing the wattage, etc.), a method of increasing the reflection efficiency of the reflection member near the connection part, and For example, a method of reducing the diffusivity of the diffusion plate added to the light guide plate only in the vicinity of the connection portion (that is, reducing the concentration of diffusing particles in the diffusion plate) is effective.

Therefore, by adding the configuration shown in FIG. 11 (b) to the illuminating device main body 14 of the present invention, a plurality of the illuminating device main bodies 14 are connected in the direction of the axis of the linear light source and the direction orthogonal thereto. It is possible to provide a large-sized planar lighting device without any problem.
According to the present invention, when a planar lighting device is enlarged, a plurality of lighting units as unit structures of the planar lighting device are connected to provide a planar lighting device of a desired size. There is no need to manufacture a planar lighting device of a size, and it is possible to reduce costs, improve yield, and facilitate manufacturing.

  Although the planar lighting device of the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

  For example, in the planar lighting device using the light guide plate according to the present invention, the shape of the light guide plate is not limited to the exemplified one, and the characteristics of the thickness change in the direction parallel to the linear light source are particularly It is not limited.

  In addition, it is needless to say that the above-described technique is not limited to application to a planar planar illumination device, and can also be applied to a curved illumination device. For example, it can also be suitably used for an illumination device (such as a backlight for a signboard) that is wound around a cylinder.

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. It is a disassembled perspective view of one Embodiment of 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. It is a fragmentary sectional view which shows the cross section in one Embodiment of the illuminating device main body shown in FIG. (A) is the schematic diagram which looked at the positional relationship of a linear light source and a reflecting plate from the back surface of a reflecting plate, (b) is the schematic diagram which looked at the positional relationship of a linear light source and a reflecting plate from the surface of the reflecting plate. is there. It is a schematic diagram which shows the positional relationship of the dot density of a linear light source and a halftone sheet. (A) And (b) is a schematic diagram which shows other embodiment of a linear light source. (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. FIG. 2 shows a planar illumination device according to another embodiment of the present invention, in which (a) is a graph showing a luminance distribution, and (b) is a perspective view showing a schematic configuration. It is the modeled perspective view which shows the basic composition of the illuminating device main body which concerns on other embodiment of this invention. FIGS. 4A and 4B show a situation where the lighting device main body shown in FIG. 3 is connected as it is, where FIG. 4A is a graph showing a luminance distribution, and FIG. 4B is a perspective view showing a schematic configuration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 11 Planar illuminating device 12 Linear light source 12a Terminal 12b, 12c Bending part 14 Illuminating device main body 14a Light emission surface 16 Case 16a Opening part 18 Inverter unit 18a Drive circuit 18b Transformer 18c Tube current detection circuit 18d Voltage control oscillation circuit DESCRIPTION OF SYMBOLS 20 Inverter accommodating part 22 Light guide plate 22a Light emission surface 22b Parallel groove 22c Thinnest part 22d Back surface 22e, 24a, 30a End surface 23 Unit light guide plate 23a Individual light emission surface 23b Thick part 23c Thin end part 23d Inclined surface 23e Inclined back part 23f Escape part 24 Diffusion plate 25 Halftone dot sheet 26 Silicon ring 28 Reflective member 30 Base 32 Through hole 34 Wire 36 Cap 40 Drive device 42 Power supply 44 Bolt 46 Nut 48 Gap 50 Lower casing 52 Upper casing 54 Diffusion sheet

Claims (7)

A linear light source having electrode portions at both ends;
A light guide plate that diffuses the light emitted from the linear light source and emits the light from the light exit surface;
A diffusion plate for diffusing illumination light emitted from the light exit surface of the light guide plate;
A reflection member having a light reflection surface for reflecting light from the linear light source;
Each of the linear light sources has at least one bent portion at each end,
The planar illumination device, wherein the electrode portion of the linear light source is disposed on the back side of the light reflecting surface of the reflecting member. A linear light source having electrode portions at both ends;
A light guide plate that diffuses the light emitted from the linear light source and emits the light from the light exit surface;
A diffusion plate for diffusing illumination light emitted from the light exit surface of the light guide plate;
A reflection member having a light reflection surface for reflecting light from the linear light source;
Each of the linear light sources has at least one bent portion at each end,
The electrode portion of the linear light source has a plurality of planar illumination units arranged on the back side of the light reflecting surface of the reflecting member,
A plurality of the planar illumination units are connected in the extending direction of the linear light source, and adjacent side surfaces are connected to each other. A light transmittance adjusting means disposed on the light exit surface side of the light guide plate;
3. The light transmittance adjusting unit according to claim 1, wherein the light transmittance in the vicinity of the bent portion of the linear light source of the light guide plate is lower than the light transmittance in other portions. Planar lighting device.   The planar illumination device according to claim 3, wherein the light transmittance adjusting means is a sheet-like member disposed on the light exit surface of the light guide plate.   The planar illumination device according to claim 3, wherein the light transmittance adjusting means is directly formed on the light exit surface of the light guide plate. The light guide plate is
A rectangular individual light exit surface;
One or more parallel grooves for accommodating the linear light sources on the surface opposite to the individual light exit surface;
A unit structure in which the thickness in the direction perpendicular to the individual light exit surface decreases in the plane perpendicular to the direction in which the parallel grooves extend is 1 in the direction perpendicular to the direction in which the parallel grooves extend. Have more than one,
The planar illumination device according to any one of claims 1 to 5, wherein light incident from the linear light source is diffused and emitted from the light exit surface.   Furthermore, the electrode part of the said linear light source is arrange | positioned at the recessed part formed by the said inclined back surface of the said light-guide plate unit, and the said inclined back surface of an adjacent light-guide plate unit. .

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