JP2011034692A - Backlight device and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize luminance of a liquid crystal display device, by preventing relative position deviation between a light guide plate and an LED element caused by vibration or the like. <P>SOLUTION: The backlight device includes the light guide plate; a plurality of light sources arranged on one side part of the light guide plate; an FPC substrate for mounting the plurality of light sources; and a frame for housing the light guide plate, the plurality of light sources and the FPC substrate. A plurality of recessed parts for housing the plurality of light sources at least one by one, and a plurality of projected parts, arranged separately between the plurality of recessed parts are arranged on one side part of the light guide plate. The FPC substrate includes a body along the one side surface of the light guide plate, a plurality of light source mounting parts for mounting the plurality of light sources separately, and a plurality of connection parts for separately connecting the plurality of light source mounting parts to the body. When the light guide plate, the plurality of light sources and the FPC substrate are housed in the frame, the connection parts of the FPC substrate are deformed elastically, to urge the light source toward the recessed part of the light guide plate by elastic restoring force; and the body of the FPC substrate is sandwiched by the projected part of the light guide plate and the frame. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a backlight device and a liquid crystal display device.

Conventionally, as backlight devices mounted on a liquid crystal display device, there are known a direct type in which a light source is provided under a light diffusion plate, a side light type in which a light source is provided on a side surface of a light guide plate, and the like. In the sidelight type backlight device, for example, a plurality of light sources such as LEDs are installed. However, there is a problem that the luminance of the liquid crystal display device itself is not uniform if there is variation in the positional relationship between the LEDs and the light guide plate.
In order to solve this problem, in recent years, the FPC board on which the LED is mounted remains elastically deformed even after the backlight device is assembled, so that the LED is directed toward the light guide plate with its elastic restoring force. A technique for energizing and making the positional relationship between the LED and the light guide plate constant has been developed (see, for example, Patent Document 1). Specifically, the FPC board includes an LED mounting portion on which the LED is mounted, and a bent portion that urges the LED toward the light guide plate by pressing the LED mounting portion toward the light guide plate. A plurality of sets are provided correspondingly. Each set of bent portions individually extends from the main line portion of the FPC board.

JP 2007-280683 A

However, in the backlight device described in Patent Document 1, although the trunk portion is fixed to the housing with an adhesive or the like, the positional relationship between the LED and the light guide plate is defined only by the elastic restoring force of the bent portion. Yes. For this reason, if vibration or the like is generated after assembly and the vibration is transmitted to the bent portion, a relative positional shift occurs between the LED and the light guide plate, and as a result, the luminance of the liquid crystal display device itself becomes non-uniform. There was a risk of it.
An object of the present invention is to prevent relative positional deviation between the light guide plate and the LED element due to vibration or the like, and to make the luminance of the liquid crystal display device uniform.

In order to solve the above problems, according to one aspect of the present invention,
A light guide plate provided with a plurality of convex portions on one side,
A light source disposed in a region between adjacent convex portions of the light guide plate;
An FPC board on which the light source is mounted;
A frame that houses the light guide plate, the light source, and the FPC board;
The FPC board is
A main body along one side of the light guide plate;
A light source mounting portion on which the light source is mounted;
A connecting part that connects the light source mounting part and the main body part;
The connecting portion of the elastically deformed FPC board urges the light source toward the surface of the light guide plate by elastic restoring force, and the main body portion of the FPC board is the convex portion of the light guide plate. A backlight device is provided in which the light guide plate, the light source, and the FPC board are accommodated in the frame so as to be sandwiched between the frame and the frame.

Preferably, the backlight device includes a plurality of regions between the convex portions of the adjacent light guide plates, and at least one of the plurality of light sources is accommodated in each of the regions between the convex portions of the plurality of adjacent light guide plates. The
In the backlight device, preferably, the main body portion of the FPC board includes a plurality of connection portions and the connection portion that connects the plurality of connection portions and connects the light source mounting portion and the main body portion. The connection portion of the main body portion of the FPC board is interposed between the convex portion of the light guide plate and the frame, and is sandwiched.
In the backlight device, preferably, the connection portion of the FPC board and the convex portion of the light guide plate are fixed by an adhesive layer.

According to another aspect of the invention,
A light guide plate provided with a plurality of recesses on one side,
A plurality of light sources arranged at least one by one in the adjacent recesses;
An FPC board on which a plurality of the light sources are mounted;
A frame that houses the light guide plate, the plurality of light sources, and the FPC board,
The FPC board is
A main body along one side of the light guide plate;
A plurality of light source mounting portions on which a plurality of the light sources are mounted;
A plurality of light source mounting portions and a plurality of connecting portions that connect the main body portion;
The connecting portion of the elastically deformed FPC board urges the light source toward the surface of the light guide plate by elastic restoring force, and the main body portion of the FPC board is between the recesses of the light guide plate. A backlight device is provided in which the light guide plate, the plurality of light sources, and the FPC board are accommodated in the frame so as to be sandwiched between a region and the frame.

According to another aspect of the invention,
A backlight device;
In a liquid crystal display device having a liquid crystal display panel disposed on the observation surface side of the backlight device,
The backlight device includes:
A light guide plate provided with a plurality of convex portions on one side, a light source disposed in a region between the convex portions of the adjacent light guide plates, and
An FPC board on which the light source is mounted;
A frame that houses the light guide plate, the light source, and the FPC board;
The FPC board is
A main body along one side of the light guide plate;
A light source mounting portion on which the light source is mounted;
A connecting portion that connects the light source mounting portion and the main body portion;
The connecting portion of the elastically deformed FPC board urges the light source toward the surface of the light guide plate by elastic restoring force, and the main body portion of the FPC board is the convex portion of the light guide plate. And the frame so that the light guide plate, the light source and the FPC board are accommodated in the frame.

In the liquid crystal display device, preferably, the main body portion of the FPC board includes a plurality of other concave portions in which the light source mounting portion and the connecting portion are disposed, and a plurality of connections disposed between the plurality of other concave portions. And comprising
In the liquid crystal display device, preferably, the main body of the FPC board, wherein the connecting portion of the main body portion of the FPC board is interposed and sandwiched between a convex portion of the light guide plate and the frame. The portion and the convex portion of the light guide plate are fixed by an adhesive layer.

  According to the present invention, it is possible to prevent relative positional deviation between the light guide plate and the LED element due to vibration or the like, and to make the luminance of the liquid crystal display device uniform.

It is a front view which shows the principal part structure of the liquid crystal display device of this embodiment. It is sectional drawing along the II-II cutting line of FIG. It is sectional drawing along the III-III cutting line of FIG. It is a front view which shows schematic structure of the light-guide plate with which the liquid crystal display device of FIG. 1 is equipped. FIG. 2 is a front view illustrating a schematic configuration of an FPC board provided in the liquid crystal display device of FIG. 1. It is a front view which shows the modification of the FPC board of FIG. It is sectional drawing which shows the modification along the III-III cutting line of FIG. 1 at the time of applying the FPC board | substrate of FIG.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for carrying out the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  FIG. 1 is a front view showing a main configuration of the liquid crystal display device of the present embodiment. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. As shown in FIGS. 1 to 3, the liquid crystal display device 1 includes a liquid crystal display panel 10 and a backlight device 20 that irradiates the liquid crystal display panel 10 with light.

  The liquid crystal display panel 10 includes a first substrate 11 on which various circuit components are mounted and a second substrate 12 that is a glass substrate, and a resin layer (not shown) is sealed between the substrates 11 and 12. It is formed by.

  The backlight device 20 includes a light guide plate 21, a plurality of light sources 22 disposed on one side of the light guide plate 21, an FPC board 23 on which the plurality of light sources 22 are mounted, a light guide plate 21, a plurality of light sources 22, and And a frame 24 that accommodates the FPC board 23.

  FIG. 4 is a front view showing a schematic configuration of the light guide plate 21. As shown in FIG. 4, the one side portion 211 of the light guide plate 21 is individually provided between the plurality of concave portions 212 having a rectangular shape in front view and accommodating the plurality of light sources 22 one by one. A plurality of convex portions 213 having a rectangular shape in front view are provided. That is, the concave portion 212 sandwiched between the convex portions 213 is a region between the convex portions, and the convex portion 213 sandwiched between the concave portions 212 is a region between the concave portions. And the convex part 213 protrudes rather than the inner surface 212a along the one side surface of the light-guide plate 21 in the recessed part 212. FIG.

  FIG. 5 is a front view showing a schematic configuration of the FPC board 23. As shown in FIG. 5, the FPC board 23 has a main body 231 along one side of the light guide plate 21, a plurality of light source mounting portions 232 on which a plurality of light sources 22 are individually mounted, and a plurality of light source mountings. A plurality of connecting portions 234 for individually connecting the portion 232 and the main body portion 231, and a connecting portion 235 that is pulled out from the main body portion 231 and connected to an external terminal are provided.

On the light guide plate 21 side of the main body 231, a first recess (another recess) 236 in which the light source mounting portion 232 and the connecting portion 234 are disposed is formed so as to correspond to the recess 212 of the light guide plate 21. A space between the first concave portions 236 on the light guide plate 21 side in the main body portion 231 serves as a joint portion 237 joined to the convex portion 213 of the light guide plate 21. On the other hand, a plurality of second concave portions 238 are formed on the side opposite to the light guide plate 21 side in the main body portion 231 so as to correspond to the joint portions 237, respectively. Thereby, the main-body part 231 is formed so that it may meander as a whole.
The light source 22 is mounted inside the light source mounting portion 232 at a predetermined interval from the tip (see FIG. 2). A tip portion of the light source mounting portion 232 that protrudes from the light source 22 is referred to as a light source mounting portion side tip portion 232a.

  The connecting portion 234 extends from a substantially central portion of the first recess 236, and the light source mounting portion 232 is connected to the tip portion thereof. The light source mounting part 232 is arranged at a predetermined interval from the joint part 237 of the main body part 231. Examples of the light source 22 mounted on the light source mounting unit 232 include an LED.

  As shown in FIGS. 1 to 3, the frame 24 houses the light guide plate 21, the plurality of light sources 22, and the FPC board 23, and the liquid crystal display panel 10. On the observation side of the frame 24, a panel recess 241 for accommodating the liquid crystal display panel 10 is formed. A light guide plate recess 242 for accommodating the light guide plate 21 is formed on the opposite side of the frame 24 from the observation side. An opening 243 serving as an optical path is formed on the bottom surface of each of the recesses 241 and 242, and the light emitted from the light source 22 and diffused by the light guide plate 21 reaches the liquid crystal display panel 10 through the opening 243. In addition, a support portion 244 that supports the FPC board 23 is formed on the frame 24 so as to be interposed between the light guide plate 21 and the liquid crystal display panel 10. The support portion 244 is formed along one side portion of the light guide plate 21 so as to face all of the plurality of convex portions 213 of the light guide plate 21.

  When the light guide plate 21, the plurality of light sources 22, and the FPC board 23 are accommodated in the frame 24, the light guide plate 21 and the FPC are accommodated so that one light source 22 is accommodated in each recess 212 of the light guide plate 21. The substrate 23 is aligned. At this time, the connecting portion 234 of the FPC board 23 is elastically deformed and bent as shown in FIG. In FIG. 2, since the frame 24 is disposed below the connecting portion 234, the connecting portion 234 is bent so as to protrude toward the side where the frame 24 is not disposed (upper side in FIG. 2). . The light source 22 on the light source mounting portion 232 is urged into the concave portion 212 of the light guide plate 21 by the elastic restoring force of the elastically deformed connecting portion 234, so that the positional relationship between the light source 22 and the light guide plate 21 is stabilized. .

After that, when the aligned light guide plate 21 and FPC board 23 are accommodated in the frame 24, the FPC is interposed between the support portion 244 of the frame 24 and the convex portion 213 of the light guide plate 21, as shown in FIG. The joint portion 237 of the substrate 23 is interposed. Here, the overlapping region R1 in which the frame 24 and the convex portion 213 of the light guide plate 21 overlap and sandwich the joint portion 237 of the FPC board 23 has a width H1 of the joint portion 237 so that the entire joint portion 237 can be sandwiched. Is set larger than.
2, the length L1 from the inner side surface 242a of the light guide plate recess 242 in the frame 24 to the inner side surface 212a of the recess 212 in the light guide plate 21 is the main body side of the FPC board 23 when bent. It is set to be smaller than the length L2 from the base end portion 231a to the light source mounting portion side distal end portion 232a. As a result, the light source mounting portion side front end portion 232 a is interposed in the overlapping region of the frame 24 and the light guide plate 21.
If these are fixed to the frame 24, the joint portion 237 and the light source mounting portion side front end portion 232 a of the FPC board 23 are sandwiched between the support portion 244 of the frame 24 and the convex portion 213 of the light guide plate 21. become.
Next, the liquid crystal display panel 10 is accommodated in the panel recess 241 on the observation side of the frame 24, whereby the liquid crystal display device 1 is assembled.

  As described above, according to the present embodiment, since the light source 22 is urged toward the concave portion 212 of the light guide plate 21 by the elastic restoring force of the connecting portion 234 in the FPC board 23, the light source 22 is always pressed against the light guide plate 21. Thus, the positional relationship between the two is stabilized. In addition, since the main body portion 231 of the FPC board 23 is sandwiched between the convex portion 213 of the light guide plate 21 and the frame 24, even if there is vibration after assembly, the relative positional deviation between the light guide plate 21 and the light source 22 is not increased. It becomes difficult to occur. By these things, the relative position shift of the light-guide plate 21 and the light source 22 by a vibration etc. can be prevented, and the brightness | luminance of the liquid crystal display device 1 can be made more uniform.

Note that the present invention is not limited to the above embodiment, and can be modified as appropriate.
For example, in the present embodiment, the case where the joint portion 237 of the FPC board 23 is simply sandwiched between the support portion 244 of the frame 24 and the convex portion 213 of the light guide plate 21 has been described as an example. If an adhesive layer is interposed between the joint portion 237 and the convex portion 213 of the light guide plate 21 and both are fixed by this adhesive layer, relative displacement between the light guide plate 21 and the light source 22 is further prevented. be able to.
Further, in the present embodiment, the case where only one light source 22 is accommodated for each recess 212 of the light guide plate 21 is exemplified, but two or more light sources 22 may be accommodated in one recess 212. .

Furthermore, in this embodiment, the case where a plurality of second recesses 238 are formed on the main body portion 231 of the FPC board 23 on the side opposite to the light guide plate 21 side has been described, but FIG. Like the FPC board 23a shown, the second recess 238 can be omitted, and the end of the main body 231 opposite to the light guide plate 21 can be continued linearly. Thus, the thickness of the main body portion 231 can be ensured and the strength of the FPC board 23a can be increased as compared with the case where the second recess 238 is provided.
Further, in the case of this FPC board 23a, since the second recess 238 is omitted, the main body part 231 of the FPC board 23a is connected to the light guide plate 21 and the frame 24 from the end of the overlapping region R1, as shown in FIG. It will be in between. That is, the area sandwiched between the light guide plate 21 and the frame 24 in the FPC board 23a is wider than in the case of the above embodiment (see, for example, FIG. 3). As a result, the FPC board 23a can be more firmly fixed.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 10 Liquid crystal display panel 11 1st board | substrate 12 2nd board | substrate 20 Backlight apparatus 21 Light guide plate 22 Light source 23 FPC board 24 Frame 211 One side part 212 Concave part 212a Inner side surface 213 Convex part 231 Main body part 232 Light source mounting part 234 Connection portion 235 Connection portion 236 First recess 237 Joint portion 238 Second recess 241 Panel recess 242 Light guide plate recess 243 Opening 244 Support portion

Claims (6)

A light guide plate provided with a plurality of convex portions on one side,
A light source disposed in a region between adjacent convex portions of the light guide plate;
An FPC board on which the light source is mounted;
A frame that houses the light guide plate, the light source, and the FPC board;
The FPC board is
A main body along one side of the light guide plate;
A light source mounting portion on which the light source is mounted;
A connecting part that connects the light source mounting part and the main body part;
The connecting portion of the elastically deformed FPC board urges the light source toward the surface of the light guide plate by elastic restoring force, and the main body portion of the FPC board is the convex portion of the light guide plate. The light guide plate, the light source, and the FPC board are accommodated in the frame so as to be sandwiched between the frame and the frame. A plurality of adjacent regions between the convex portions of the light guide plate;
The backlight device according to claim 1, wherein at least one of the plurality of light sources is accommodated in a region between the convex portions of the plurality of adjacent light guide plates. The main body portion of the FPC board includes a plurality of connection portions, and a predetermined region in which the connection portions that connect the light source mounting portions and the main body portion are arranged to connect the plurality of connection portions.
3. The backlight according to claim 1, wherein the connection portion of the main body portion of the FPC board is interposed and sandwiched between a convex portion of the light guide plate and the frame. apparatus.   4. The backlight device according to claim 1, wherein the connection portion of the FPC board and the convex portion of the light guide plate are fixed by an adhesive layer. 5. A light guide plate provided with a plurality of recesses on one side,
A plurality of light sources arranged at least one by one in the adjacent recesses;
An FPC board on which a plurality of the light sources are mounted;
A frame that houses the light guide plate, the plurality of light sources, and the FPC board,
The FPC board is
A main body along one side of the light guide plate;
A plurality of light source mounting portions on which a plurality of the light sources are mounted;
A plurality of light source mounting portions and a plurality of connecting portions that connect the main body portion;
The connecting portion of the elastically deformed FPC board urges the light source toward the surface of the light guide plate by elastic restoring force, and the main body portion of the FPC board is between the recesses of the light guide plate. The backlight device, wherein the light guide plate, the plurality of light sources, and the FPC board are accommodated in the frame so as to be sandwiched between a region and the frame. A backlight device;
In a liquid crystal display device having a liquid crystal display panel disposed on the observation surface side of the backlight device,
The backlight device includes:
A light guide plate provided with a plurality of convex portions on one side, and a light source disposed in a region between the convex portions of the adjacent light guide plates;
An FPC board on which the light source is mounted;
A frame that houses the light guide plate, the light source, and the FPC board;
The FPC board is
A main body along one side of the light guide plate;
A light source mounting portion on which the light source is mounted;
A connecting part that connects the light source mounting part and the main body part;
The connecting portion of the elastically deformed FPC board urges the light source toward the surface of the light guide plate by elastic restoring force, and the main body portion of the FPC board is the convex portion of the light guide plate. The light guide plate, the light source, and the FPC board are accommodated in the frame so as to be sandwiched between the frame and the frame.

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