JP2011023209A - Backlight device and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight device and a liquid crystal display device which can suppress luminance unevenness and chromaticity unevenness and can improve luminance of an entire liquid crystal display panel. <P>SOLUTION: A plurality of LED mounting frames 303 for arranging LEDs 304 one by one are formed on an LED mounting substrate 302. A reflection sheet 310 is arranged behind a light emitting part of the LED 304 in the LED mounting frame 303, and reflects light from the LED 304 forward. A diffusion sheet 320 is arranged in a position in the front of the light emitting part of the LED 304, and diffuses light applied from behind. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a backlight device used in a liquid crystal display device and a liquid crystal display device including the backlight device.

  In recent years, light emitting diodes (LEDs) have been used as light sources for backlight devices used in liquid crystal display devices, instead of conventional cold cathode fluorescent lamps (CCFLs). . The liquid crystal display device using such a backlight device has been widely put into practical use because the amount of heat generation and power consumption are suppressed, but the light emitting diodes have individual variations in luminance or chromaticity, and remain as they are. If used, there is a problem that it is difficult to uniformly illuminate the entire surface of the liquid crystal display panel of the liquid crystal display device.

  Thus, for example, light in which a photosensitive material containing a diffusing material is applied between a light emitting diode and a diffusing plate is used to suppress luminance unevenness and chromaticity unevenness of a backlight device used in a liquid crystal display device. There is one in which a transmissive substrate is disposed opposite to a light emitting diode, and chromaticity unevenness or luminance is adjusted by changing the density of a diffusing material in accordance with the amount of light from the light emitting diode (Patent Document 1). ).

JP 2006-310042 A

  However, the backlight device used in the conventional liquid crystal display device can suppress chromaticity unevenness or luminance unevenness, but cannot improve the luminance of the entire liquid crystal display panel of the liquid crystal display device.

  An object of the present invention is to provide a backlight device and a liquid crystal display device capable of suppressing luminance unevenness or chromaticity unevenness and improving the luminance of the entire liquid crystal display panel.

In order to solve the above problems, the invention according to claim 1 is a backlight device in which a plurality of light emitting diodes are arranged on a substrate.
The substrate is provided with a plurality of arrangement regions for arranging the light emitting diodes one by one,
In the arrangement region, a light emitting part of the light emitting diode is arranged behind the light emitting diode, a reflection member for reflecting light from the light emitting diode forward, and a light emitting part of the light emitting diode are arranged in front of the light emitting diode. And a diffusing member for diffusing the light irradiated from.

  A second aspect of the present invention is the backlight device according to the first aspect, wherein the reflecting member and the diffusing member are configured to be detachable from the arrangement region.

Invention of Claim 3 is the backlight apparatus of Claim 1 or 2, Comprising: The said reflection member and the said diffusing member are back from the main-body part formed in the sheet form, and the edge part of a main-body part. And an engaging portion formed by bending to
The arrangement area is provided with an engagement hole with which the engagement portion is engaged,
The engaging portion is engaged with an engaging hole, and the reflecting member and the diffusing member are attached to the arrangement region.

Invention of Claim 4 is the backlight apparatus of Claim 3, Comprising: The boss | hub which protrudes ahead predetermined length rather than the light emission part of the said light emitting diode is provided in the said arrangement | positioning area | region,
When the diffusion member is attached to the arrangement region, the back surface of the main body is in contact with the boss so that the light emitting portion of the light emitting diode and the main body are spaced apart from each other by a predetermined distance. To do.

  Invention of Claim 5 is a backlight apparatus as described in any one of Claims 1-4, Comprising: The said arrangement | positioning area | region is formed by regular hexagon shape, and arranges and arranges in a honeycomb form. Features.

The invention according to claim 6 is a backlight device in which a plurality of light emitting diodes are arranged on a substrate.
In the substrate, a plurality of arrangement regions formed by regular hexagonal shapes for arranging the light emitting diodes one by one are arranged in a honeycomb shape,
In the arrangement region, a light emitting part of the light emitting diode is arranged behind the light emitting diode, a reflection member for reflecting light from the light emitting diode forward, and a light emitting part of the light emitting diode are arranged in front of the light emitting diode. A diffusing member for diffusing the light irradiated from the detachable,
The reflecting member and the diffusing member have a main body portion formed in a sheet shape, an engagement portion that is formed by bending backward from an end portion of the main body portion and elastically deformable,
The arrangement area is provided with an engagement hole with which the engagement portion is engaged,
After the engaging portion is elastically deformed and inserted into the engaging hole, the engaging portion is engaged with the engaging hole by the return of the elastic deformation of the engaging portion, and the reflecting member and the diffusing member Is attached to the placement area,
The arrangement region is further provided with a boss protruding forward by a predetermined length from the light emitting portion of the light emitting diode,
When the diffusion member is attached to the arrangement region, the back surface of the main body is in contact with the boss so that the light emitting portion of the light emitting diode and the main body are spaced apart from each other by a predetermined distance. To do.

  According to a seventh aspect of the present invention, in the liquid crystal display device, the backlight device according to any one of the first to sixth aspects is provided.

  According to the present invention, it is possible to provide a backlight device and a liquid crystal display device capable of suppressing luminance unevenness or chromaticity unevenness and improving the luminance of the entire liquid crystal display panel.

It is the schematic showing the outline of the principal part structure of the liquid crystal display device which concerns on this embodiment. It is the schematic showing the outline of the principal part structure of the LED panel which concerns on this embodiment. It is a schematic diagram which represents typically the structure of the LED attachment board which concerns on this embodiment. It is a schematic diagram which represents typically the structure of the LED attachment frame which concerns on this embodiment. It is a figure showing the state which attached the reflective sheet to the LED attachment frame. It is sectional drawing showing the AA cross section in FIG. It is a figure showing the state which attached the diffusion sheet to the LED attachment frame. It is sectional drawing showing the BB cross section in FIG. It is a figure showing the state which attached the reflection sheet and the diffusion sheet to the LED attachment frame. It is sectional drawing showing CC cross section in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the liquid crystal display device 1 includes a liquid crystal display panel 100, a whole surface diffusion sheet 200, and an LED panel 300 that are arranged in the depth direction from the front side.
As the liquid crystal display panel 100, a known liquid crystal display panel whose display state is easily visually recognized when light is irradiated from the back side is used.
The entire surface diffusion sheet 200 is a sheet for diffusing light so that light irradiated from the LED panel 300 is evenly irradiated to the entire surface of the liquid crystal display panel 100.
The LED panel 300 irradiates light from the back surface of the liquid crystal display panel 100 with a number of white light emitting LEDs, and makes it easy to visually recognize an image displayed on the liquid crystal display panel 100.

  Next, the structure of the LED panel 300 of this embodiment will be described in detail.

As shown in FIG. 2, the LED panel 300 includes a board mounting base 301, and a plurality of LED mounting boards 302 are arranged on the board mounting base 301 in a matrix in a predetermined number of length and width.
On the LED mounting substrate 302, seven regular hexagonal LED mounting frames 303 are arranged in a honeycomb shape. More specifically, the LED mounting frame 303a is disposed substantially at the center of the LED mounting substrate 302, and the LED mounting frames 303b to 303g are disposed adjacent to the sides of the LED mounting frame 303a.
Further, an LED 304 that emits white light is provided at the center of each LED mounting frame 303. Further, although not shown, electrodes such as a clock signal line and a data signal line from the driver are formed between the LED mounting boards of the board mounting base 301. Each LED mounting board 302 is connected to a clock signal line and a data signal line, and when a voltage is applied from both, the LEDs 304 mounted on the LED mounting board 302 are configured to emit light simultaneously. ing.
Thus, the LED panel 300 constitutes a backlight device in which a plurality of light emitting diodes are arranged on the substrate.
Further, the LED mounting frame 303 constitutes an arrangement area for arranging the light emitting diodes one by one.

  Next, the structure of the LED mounting substrate 302 of this embodiment will be described.

As shown in FIG. 3, the LED mounting board 302 is formed in a square thin plate shape, and seven LED mounting frames 303 are slightly concave with respect to the LED mounting board 302 on the upper surface of the LED mounting board 302. Is formed.
Each LED attachment frame 303 is attached with a reflection sheet 310 as a reflection member and a diffusion sheet 320 as a diffusion member.

  Here, the structure of the LED mounting frame 303 of the present embodiment will be described in detail with reference to FIGS.

As shown in FIG. 4, the LED mounting frame 303 constitutes a part of the LED mounting substrate 302 and is formed by a regular hexagonal recess.
At the bottom 305 of the LED mounting frame 303, an LED 304 having a light emitting part 304a as a light source at the top, a boss 307 erected at a predetermined interval above and below the LED 304, and upper and lower end parts on each side An engagement hole 306 formed by an elongated opening having a predetermined length is provided.

  The LED attachment frame 303 can be attached with a reflection sheet 310 or a diffusion sheet 320 having a shape corresponding to the shape of the LED attachment frame 303. The reflection sheet 310 and the diffusion sheet 320 allow the luminance of the LED 304 or The chromaticity can be adjusted.

The reflection sheet 310 constitutes a sheet main body 311 and an engagement piece 312. The sheet main body 311 is formed in a regular hexagonal shape having substantially the same size as the bottom surface 305 of the LED mounting frame 303. The engagement piece 312 is formed in a trapezoidal shape that becomes wider from the upper and lower end portions of the sheet main body portion 311 toward the front end, is bent downward, and is formed integrally with the sheet main body portion 311. Note that the shape of the engagement piece 312 is not limited to a trapezoidal shape, and may be formed, for example, in a wedge shape that narrows toward the tip at the tip.
The reflection sheet 310 is molded from a synthetic resin such as PET or polypropylene (PP) and has flexibility. And the white printing is given to the surface of this reflection sheet 310, and reflection of light is made easy. Instead of white printing on the reflection sheet 310, the reflection sheet 310 may be molded from a resin colored in white. In addition, a transparent reflective sheet 310 is attached to the LED mounting frame 303 in advance, and direct printing is performed by spraying or the like on the sheet main body 311 of the attached reflective sheet 310 according to the measurement result of the luminance of the LED 304. Good.
In the center of the sheet main body 311, a rectangular through hole 313 having a size substantially the same as that of the LED 304 is formed, and a circular boss insertion hole having a size substantially the same as the diameter of the boss 307 is spaced above and below the through hole 313. 314 is formed.

When the reflection sheet 310 configured as described above is attached to the LED mounting frame 303, the right and left ends of the engagement piece 312 of the reflection sheet 310 are pressed and flexed to elastically deform the engagement piece 312. Then, the LED is inserted into the engagement hole 306 of the LED mounting frame 303. When the engagement piece 312 is inserted into the engagement hole 306, the elastic deformation of the engagement piece 312 is restored, and the engagement piece 312 is engaged with the engagement hole 306. Then, the reflective sheet 310 is positioned, the LED 304 passes through the through hole 313, and the pair of bosses 307 pass through the boss insertion holes 314, respectively.
Then, the reflective sheet 310 is attached to the LED mounting frame 303 by bringing the back surface of the sheet main body 311 of the reflective sheet 310 into contact with the bottom surface 305 of the LED mounting frame 303. At this time, as shown in FIGS. 5 and 6, the reflection sheet 310 is positioned behind the light emitting unit 304 a of the LED 304, and is reflected when the light from the light emitting unit 304 a of the LED 304 is irradiated backward. Reflected forward by the sheet 310, the amount of light forward increases.

On the other hand, when removing the reflective sheet 310 from the LED mounting frame 303, when the engagement piece 312 of the reflection sheet 310 is pressed from the back surface of the LED attachment board 302 in the direction opposite to the insertion direction, The end portion comes into contact with the inner periphery of the engagement hole 306, and the engagement piece 312 is elastically deformed while the left and right sides of the engagement piece 312 are guided by the inner periphery of the engagement hole 306. When the engagement piece 312 is further pressed in this state, the engagement piece 312 is detached from the engagement hole 306 and the reflection sheet 310 is removed.
Thus, the reflection sheet 310 is configured to be detachable from the LED mounting frame 303.

Here, a plurality of print patterns on the surface of the reflection sheet 310 are prepared, and the reflection sheet 310 having a print pattern corresponding to the luminance of the LED 304 is selected and attached to the LED attachment frame 303, so that it can be attached to another LED attachment frame 303. The difference in luminance from the LED 304 can be reduced. Specifically, as the light emission luminance of the LED 304 decreases, the luminance is adjusted by selecting the reflective sheet 310 having a printed pattern with high reflectance.
Note that the brightness of the LED 304 is difficult to remove once the LED 304 is mounted on the board. Therefore, the LED 304 is not attached to the LED 304 without selecting it by performing a pre-mounting light emission test, etc. After attaching to the frame 303, it is performed by using a predetermined measuring instrument.

The diffusion sheet 320 constitutes a sheet main body 321 and an engagement piece 322. The sheet main body 321 is formed in a regular hexagonal shape having substantially the same size as the bottom surface 305 of the LED mounting frame 303. The engagement piece 322 is formed in a trapezoidal shape that becomes wider from the upper and lower end portions of the sheet main body portion 321 toward the front end, is bent downward, and is formed integrally with the sheet main body portion 321. The shape of the engagement piece 322 is not limited to a trapezoidal shape, and may be formed, for example, in a wedge shape that narrows toward the tip at the tip.
The diffusion sheet 320 is molded from a synthetic resin such as PET or polycarbonate (PC) and has flexibility. The surface of the diffusion sheet 320 is printed by silk screen printing or the like so as to diffuse light. In addition to silk screen printing, as a mode of printing on the diffusion sheet 320, a photosensitive sheet is applied, a diffusion material is attached in accordance with light from the LED 304, and development processing is performed to form a diffusion sheet. It may be. Alternatively, a transparent diffusion sheet 320 may be attached to the LED mounting frame 303 in advance, and direct printing may be performed by spraying or the like on the sheet main body 321 of the attached diffusion sheet 320 according to the measurement result of the luminance of the LED 304. Good.
Unlike the sheet main body 311 of the reflection sheet 310, the sheet main body 321 is not provided with an opening.

When attaching the diffusion sheet 320 configured as described above to the LED mounting frame 303, the engagement pieces 322 are elastically deformed by pressing the left and right ends of the engagement pieces 322 of the diffusion sheet 320 to be flexible. Then, the LED is inserted into the engagement hole 306 of the LED mounting frame 303. When the engagement piece 322 is inserted into the engagement hole 306, the elastic deformation of the engagement piece 312 is restored, and when the engagement piece 322 is engaged with the engagement hole 306, the diffusion sheet 320 is positioned. The Then, as shown in FIGS. 7 and 8, since the back surface of the sheet body 321 of the diffusion sheet 320 comes into contact with the tip of the boss 307, the front surface side of the LED 304 is covered with a predetermined distance from the LED 304, and the LED is mounted. It will be arranged to face the bottom surface 305 of the frame 303.
In addition, when removing the diffusion sheet 320 from the LED attachment frame 303, it can remove by the method similar to removal of the reflective sheet 310 mentioned above.
Thus, the diffusion sheet 320 is configured to be detachable from the LED mounting frame 303.

  Here, a plurality of printing patterns on the surface of the diffusion sheet 320 are prepared, and the diffusion sheet 320 having a printing pattern corresponding to the luminance of the LED 304 is selected and attached to the LED attachment frame 303, so that it can be attached to another LED attachment frame 303. The difference in luminance from the LED 304 can be reduced.

In the present embodiment, the reflection sheet 310 and the diffusion sheet 320 can be attached to the LED attachment frame 303 at the same time.
When the reflection sheet 310 and the diffusion sheet 320 are simultaneously attached to the LED attachment frame 303, as described above, the reflection sheet 310 is first attached and then the diffusion sheet 320 is attached. When the reflection sheet 310 and the diffusion sheet 320 are attached to the LED attachment frame 303 in this way, the diffusion sheet 320 is attached so as to cover the upper surface of the reflection sheet 310 as shown in FIGS.

As described above, according to the embodiment of the present invention, the LED mounting frame 303 on which the LEDs 304 are disposed is disposed behind the light emitting portion 304a of the LEDs 304, and reflects the light from the LEDs 304 forward. The reflection sheet 310 and a diffusion sheet 320 that is disposed in front of the light emitting portion 304a of the LED 304 and diffuses light irradiated from behind is attached. As a result, even if the LED 304 having a larger difference in luminance than the other LEDs 304 is used, the reflection sheet 310 can improve the luminance of the light irradiated to the diffusion sheet 320 and can be attached to the other LED mounting frame 303. The luminance unevenness with the LED 304 can be reduced to suppress the luminance unevenness, and the diffusion sheet 320 further increases the luminance of light irradiated to the entire liquid crystal display panel 100 as compared with the conventional case. Visibility can be improved. That is, even if there is a large difference in chromaticity or brightness between the LEDs 304, chromaticity unevenness or brightness unevenness can be suppressed, and the brightness of light applied to the entire liquid crystal display panel 100 can be increased as compared with the conventional case.
In addition, according to the embodiment of the present invention, even when the LED 304 is defective and needs to be replaced, the reflective sheet 310 and / or the diffusion sheet 320 having a pattern according to the luminance of the LED 304 after replacement is selected and attached. Is also possible.

  Further, according to the embodiment of the present invention, since the reflection sheet 310 and the diffusion sheet 320 are configured to be detachable from the LED mounting frame 303, it is possible to freely change the brightness adjustment and the like, and to improve the manufacturing efficiency. Can be improved.

  Further, according to the embodiment of the present invention, the reflection sheet 310 and the diffusion sheet 320 are bent backward from the sheet main body portions 311 and 321 formed on the sheet and the end portions of the sheet main body portions 311 and 321. It has engaging pieces 312 and 322 to be formed. The LED mounting frame 303 is provided with an engagement hole 306 that engages with the engagement pieces 312 and 322. Then, the engagement pieces 312 and 322 are engaged with the engagement holes 306, and the reflection sheet 310 and the diffusion sheet 320 are attached to the LED attachment frame 303. As a result, the reflection sheet 310 and the diffusion sheet 320 can be easily attached to the LED attachment frame 303, and the production efficiency can be improved.

  Further, according to the embodiment of the present invention, the LED mounting frame 303 is provided with the boss 307 that protrudes forward by a predetermined length from the light emitting portion 304 a of the LED 304. When the diffusion sheet 320 is attached to the LED attachment frame 303, the back surface of the sheet main body portion 321 contacts the boss 307, and the light emitting portion 304a of the LED 304 and the sheet main body portion 321 are spaced apart from each other by a predetermined distance. As a result, since the diffusion sheet 320 can be placed at a predetermined distance from the light emitting portion 304a of the LED 304, the diffusion sheet 320 can receive a light source from the light emitting portion 304a of the LED 304 in a wide area, and uneven luminance is generated. Can be suppressed.

  Further, according to the embodiment of the present invention, the LED mounting frame 303 is formed in a regular hexagonal shape and arranged in a honeycomb shape, so that the light from the adjacent LEDs 304 is diffused by the diffusion sheet 320 or the entire surface diffusion sheet. 200 and the like can be reduced, and the occurrence of uneven brightness can be suppressed.

  In this embodiment, the attachment structure of the reflection sheet 310 or the diffusion sheet 320 is attached by inserting the engagement pieces 312 and 322 of the sheet into the engagement holes 306 of the LED attachment frame 303. You may make it stick on the bottom face 305 of LED attachment frame 303 with a double-sided tape.

  In this embodiment, the reflection sheet 310 or the diffusion sheet 320 is detachable from the LED mounting frame 303. However, it may be configured such that it is not removable or difficult once it is attached, such as a caulking structure.

In the present embodiment, the boss 307 is erected from the bottom surface 305 of the LED mounting frame 303. However, the boss 307 may not be erected and the diffusion sheet 320 itself may have a spacer function. For example, notches are provided at both ends of the engagement piece 322 of the diffusion sheet 320, and the notches engage with both ends of the entrance of the engagement hole 306 of the LED mounting frame 303, whereby the sheet body of the LED 304 and the diffusion sheet 320 is obtained. A form in which a space with a predetermined interval is created between the unit 321 and the unit 321 may be used.
In addition, any method can be applied as long as a space having a predetermined interval can be created between the LED 304 and the sheet main body 321 of the diffusion sheet 320. In this case, those that do not affect the irradiation of light from the LED 304 are suitable.

  Moreover, in this Embodiment, although the shape of the LED attachment frame 303 was made into the regular hexagon shape, other shapes, such as a square shape and a circular shape, may be sufficient.

  Further, in the present embodiment, the shapes of the reflection sheet 310 and the diffusion sheet 320 are matched to the shape of one LED mounting frame 303. For example, two or more reflection sheets 310 or diffusion sheets 320 are integrated. It may be formed so that it can be mounted over a plurality of LED mounting frames 303, and may be applied when, for example, LEDs 304 having the same luminance are continuously arranged.

  Further, in the present embodiment, the LED 304 that emits white light is used. However, a full color LED that can control light emission independently for each of RGB may be used.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 100 Liquid crystal display panel 200 Whole surface diffusion sheet 300 LED panel (backlight apparatus)
301 board mounting base 302 LED mounting board 303 LED mounting frame (arrangement area)
304 LED (light emitting diode)
304a Light emitting part 305 Bottom face part 306 Engagement hole 307 Boss 310 Reflective sheet (reflective member)
311 Sheet body (body)
312 Engagement piece (engagement part)
320 Diffusion sheet (Diffusion member)
321 Seat body (body)
322 engagement piece (engagement part)

Claims (7)

In a backlight device in which a plurality of light emitting diodes are arranged on a substrate,
The substrate is provided with a plurality of arrangement regions for arranging the light emitting diodes one by one,
In the arrangement region, a light emitting part of the light emitting diode is arranged behind the light emitting diode, a reflection member for reflecting light from the light emitting diode forward, and a light emitting part of the light emitting diode are arranged in front of the light emitting diode. And a diffusing member for diffusing the light irradiated from the backlight device.   The backlight device according to claim 1, wherein the reflecting member and the diffusing member are configured to be detachable from the arrangement region. The reflecting member and the diffusing member have a main body portion formed in a sheet shape, and an engaging portion formed by bending backward from an end portion of the main body portion,
The arrangement area is provided with an engagement hole with which the engagement portion is engaged,
The backlight device according to claim 1, wherein the engaging portion is engaged with an engaging hole, and the reflecting member and the diffusing member are attached to the arrangement region. The arrangement region is provided with a boss protruding forward by a predetermined length from the light emitting portion of the light emitting diode,
When the diffusion member is attached to the arrangement region, the back surface of the main body is in contact with the boss so that the light emitting portion of the light emitting diode and the main body are spaced apart from each other by a predetermined distance. The backlight device according to claim 3.   The backlight device according to claim 1, wherein the arrangement region is formed in a regular hexagonal shape and arranged in a honeycomb shape. In a backlight device in which a plurality of light emitting diodes are arranged on a substrate,
In the substrate, a plurality of arrangement regions formed by regular hexagonal shapes for arranging the light emitting diodes one by one are arranged in a honeycomb shape,
In the arrangement region, a light emitting part of the light emitting diode is arranged behind the light emitting diode, a reflection member for reflecting light from the light emitting diode forward, and a light emitting part of the light emitting diode are arranged in front of the light emitting diode. A diffusing member for diffusing the light irradiated from the detachable,
The reflecting member and the diffusing member have a main body portion formed in a sheet shape, an engagement portion that is formed by bending backward from an end portion of the main body portion and elastically deformable,
The arrangement area is provided with an engagement hole with which the engagement portion is engaged,
After the engaging portion is elastically deformed and inserted into the engaging hole, the engaging portion is engaged with the engaging hole by the return of the elastic deformation of the engaging portion, and the reflecting member and the diffusing member Is attached to the placement area,
The arrangement region is further provided with a boss protruding forward by a predetermined length from the light emitting portion of the light emitting diode,
When the diffusion member is attached to the arrangement region, the back surface of the main body is in contact with the boss so that the light emitting portion of the light emitting diode and the main body are spaced apart from each other by a predetermined distance. Backlight device to do.   A liquid crystal display device comprising the backlight device according to claim 1.

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