JP2002031791A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device that can be made thin and light and can prevent a defective display. SOLUTION: The liquid crystal display device is provided with a liquid crystal display panel 10 having a liquid crystal layer interposed between a pair of substrates, a backlight unit 12 for illuminating the liquid crystal display panel, a holding frame 24 for holding the liquid crystal display panel and the backlight unit and a bezel 14 fixed to the holding frame so as to disposing the liquid crystal display panel and the backlight unit between the holding frame and the bezel A supporting member 70 supports the bezel 14 so as to form a gap between the bezel 14 and the liquid crystal display panel 10. The holding frame 24 has a receiving surface 24h for receiving the liquid crystal display panel 10, and an edge 24j of the receiving surface 24h is chamfered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a structure for preventing occurrence of display failure even when stress is applied to the liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device includes a surface light source device for illuminating a transmission type liquid crystal display panel from the back. Electronic devices such as portable personal computers equipped with such a liquid crystal display device are desired to be reduced in size and weight due to their properties, and are required to have high strength. In order to respond to these conflicting demands, improvements have been made to the driving circuit, the packaging technology, and the structure of the liquid crystal display device.

[0003] Against this background, a liquid crystal display device having a narrow frame whose distance between the outer edge and the edge of the display screen is about several mm has been put to practical use. Also, the thickness is required to be thin, and a liquid crystal display device that meets the requirement that the total thickness is 5 mm or less has been put to practical use.

The liquid crystal display device having such a structure has a reduced strength against stress applied from the outside. For this reason, when stress such as twisting the liquid crystal display device due to external vibration or impact is applied, the metal frame that sandwiches the liquid crystal display device with the plastic frame partially presses the liquid crystal display panel. When the plastic frame partially pushes up the liquid crystal display panel, a display defect such as a waving phenomenon occurs in a part of the liquid crystal display panel.

[0005]

As described above, the demand for thinning the liquid crystal display device is strict, and the thickness of the light guide constituting the surface light source device has reached the limit in the optical specifications, and the thickness of the liquid crystal display device has been limited. Regarding the strength of the frame and liquid crystal display panel,
The limit has been reached in manufacturing. For this reason, the thickness of the metal frame is reduced, and the strength of the liquid crystal display device against twisting is reduced.

Therefore, when a stress such as a twist is applied to the liquid crystal display device, the probability that a display defect such as a waving phenomenon occurs in a part of the liquid crystal display panel is increased.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and has as its object to provide a liquid crystal display device which can realize a thin and light weight and can prevent occurrence of display defects. It is in.

[0008]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: a liquid crystal display panel having a liquid crystal layer sandwiched between a pair of substrates; A surface light source unit that illuminates a panel, a first frame that holds the liquid crystal display panel and the surface light source unit, and the first frame that is arranged between the first frame and the liquid crystal display panel and the surface light source unit. A second frame fixed to one frame, comprising: a support portion for supporting the second frame so as to form a gap between the second frame and the liquid crystal display panel. The first frame has a receiving surface for receiving the liquid crystal display panel, and an edge of the receiving surface is chamfered.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the liquid crystal display device of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the liquid crystal display device includes a transmissive liquid crystal display panel 10, an edge light type surface light source device that illuminates the liquid crystal display panel 10 from the back side, that is, a backlight unit 12, and a rectangular frame. Metal frame, that is, the bezel 14 is laminated.

The liquid crystal display panel 10 controls a rectangular array substrate 100 and a counter substrate 200, a twisted nematic liquid crystal layer 300 sealed between these substrates via an alignment film, respectively, and the liquid crystal display panel 10. The control circuit boards 510 and 520, the drive integrated circuit 600 for electrically connecting the liquid crystal display panel 10 to the control circuit boards 510 and 520, and supplying drive signals to the liquid crystal display panel 10 are provided. The array substrate 100 includes a sealing material 331.
Is bonded to the opposing substrate 200 via the. The outer surfaces of each of the substrates 100 and 200 have polarizing plates 190 and 29 arranged so that their polarization axes are orthogonal to each other.
Covered by 0.

The array substrate 100 is, for example, 1024 × 3
The signal line 115 includes 768 scanning lines 113 arranged to be orthogonal to each other. In the vicinity of the intersection between each signal line 115 and each scanning line 113, a thin film transistor, that is, a TFFT in which an amorphous silicon film or a polysilicon film is used in the channel region is used.
T117 is arranged. The gate electrode of the TFT 117 is electrically connected to the scanning line 113. TF
The drain electrode of T117 is electrically connected to the signal line 115. The source electrode of the TFT 117 is electrically connected to a pixel electrode 119 formed of a transparent conductive member, for example, ITO (indium-tin-oxide).

The drive integrated circuit 600 for electrically connecting the array substrate 100 and the control circuit substrate 510 includes a signal line 11
And a signal line driving integrated circuit 610 electrically connected to the signal line driving integrated circuit 610. The array substrate 100 and the control circuit substrate 52
0 is electrically connected to the scanning line driving integrated circuit 620 which is electrically connected to the scanning line 113.
It has.

The signal line driving integrated circuit 610 converts a digital image signal input from the outside into a desired analog signal voltage based on the control signal and outputs the converted signal, and a shift register, a digital-analog conversion circuit, and the like. It is composed of a buffer circuit and the like. Further, the scanning line driving integrated circuit 620 includes a shift register, a buffer circuit, and the like so as to sequentially transfer and output scanning pulses based on a control signal input from the outside.

The opposing substrate 200 includes a color filter layer arranged for each pixel area, and an opposing electrode 217 formed of a transparent conductive member, for example, ITO. The color filter layer is formed of, for example, a colored resin colored red, green, and blue, respectively.

Next, the structure of a surface light source device applied to this liquid crystal display device, that is, a backlight unit will be described.

As shown in FIGS. 1 and 2, the backlight unit 12 includes a rectangular plate-shaped plastic frame, that is, a holding frame 24, a light guide 26, and a plurality of sheet members, for example, three optical sheets 28 and 30. , 32, an elongated tubular cold cathode ray tube 33 as a light source, a protective cover 34
Etc. are provided.

The holding frame 24 is made of, for example, a synthetic resin and has a rectangular storage recess 36. The holding frame 24 includes a fitting portion 24f that fits into a positioning portion of the light guide 26 described later in order to position the light guide 26. In the case of the embodiment as shown in FIG. 2, the fitting portion 24f is formed in a concave shape on one side of the holding frame 24.

The holding frame 24 has four side walls 2.
In addition to 4a, 24b, 24c and 24d, a receiving surface 24g for receiving the light guide 26 and a receiving surface 24h for forming the receiving recess 36 for receiving the light guide 26 and receiving the liquid crystal display panel 10 are formed. Have.

The optical sheet 28 is a reflection sheet made of, for example, milky white polyimide resin, and is formed in a rectangular shape having substantially the same size as the storage recess 36 of the holding frame 24.

The light guide 26 is formed of, for example, an acrylic resin, and is formed in a rectangular shape having substantially the same size as the storage recess 36 of the holding frame 24. This light guide 26
Has a thick portion 26a on one side thereof, a thin portion 26b on a side facing the thick portion 26a, and has a wedge-shaped cross section. One side surface 26d of the thick portion 26a of the light guide 26 is disposed to face the cold cathode ray tube 33, and serves as an incident surface on which light emitted from the cold cathode ray tube 33 enters.
On the back surface 26e side of the light guide 26, the reflection sheet 2 described above is provided.
8 are provided.

One main surface of the light guide 26, that is, a main plane 26c opposed to the back surface 26e on which the reflection sheet 28 is provided.
Is an emission surface from which light incident from the incident surface 26d is emitted. In addition, the light guide 26 has a positioning portion 26f for positioning with respect to the holding frame 24 on one side thereof.
It has. In the case of the embodiment shown in FIG.
The positioning part 26f is formed in a convex shape protruding from one side of the thin part 26b corresponding to the concave fitting part 24f formed in the holding frame 24. The light guide 26 is positioned by fitting its positioning portion 26f to the fitting portion 24f of the holding frame 24.

The optical sheet 30 is, for example, a diffusion sheet and is formed in a rectangular shape having substantially the same size as the storage recess 36. The optical sheet 30 is laminated on the light exit surface 26c of the light guide 26. The optical sheet 32 is a prism sheet and is formed in a rectangular shape having substantially the same size as the storage recess 36. The optical sheet 32 is laminated on the diffusion sheet 30.

In the vicinity of the side wall 24a of the holding frame 24, an elongated lamp accommodating groove 40 extending over the entire length in the width direction is formed. A rib 41 having substantially the same height as the side wall 24a is provided upright at a central portion in the longitudinal direction of the lamp accommodating groove 40, and extends along the longitudinal direction of the lamp accommodating groove 40 and a predetermined distance from the inner surface of the side wall 24a. It extends at intervals.

A cold cathode ray tube 33 is accommodated in the region of the lamp accommodating groove 40 on the side of the accommodating recess 36 of the rib 41. That is, the cold cathode ray tube 33 is assembled integrally with the reflector 48 in a state where both ends are supported by the holder 42 in a predetermined positional relationship. The reflector 48 has a substantially U-shaped cross section, and the cold cathode ray tube 3
It is arranged so as to surround a peripheral surface other than the peripheral surface facing the light guide body 26 in the periphery of 2. This cold cathode ray tube 33 is
6 is disposed at a predetermined position facing the thick portion 26a.

From the pair of holders 42, the cold cathode ray tubes 33
The connection cables 44a and 44b for supplying a voltage to are connected to each other. The connection cable 44a is routed through the region between the rib 41 and the side wall 24a to the other holder 42 side in the lamp housing groove 40, and is drawn out together with the other connection cable 44b. The two connection cables 44a and 44b pulled out are as shown in FIG.
Are connected to the lamp drive circuit 46 as shown in FIG.

The upper surface of the lamp accommodating groove 40 is covered by a protective cover 34 fitted to the holding frame 24. The protective cover 34 is formed by bending a thin metal plate into an L shape, and has an elongated upper surface wall 50 that covers the lamp accommodating groove 40.
a and a side wall 50b fitted to the outer surface of the side wall 24a of the holding frame 24.

During the operation of the liquid crystal display device, part of the light emitted from the cold cathode ray tube 33 directly enters the light guide 26 from the incident surface 26d of the light guide 26, and the remaining light is reflected by the reflector 48. After being reflected by the light guide 26, the light enters the light guide 26 through the incident surface 26d. The incident light propagates through the entire inside of the light guide 26, and the light exit surface 26 of the light guide 26
The light exits from c toward the diffusion sheet 30.

Light leaking from the light guide 26 to the reflection sheet 28 is reflected by the reflection sheet 28 and reenters the light guide 26. Light emitted from the emission surface 26c of the light guide 26 is diffused by the diffusion sheet 30 and guided to the entire surface of the liquid crystal display panel 10 by the prism sheet 32.

In the liquid crystal display panel 10, transmission and non-transmission of light guided for each pixel is selectively controlled, and an image is displayed.

Next, the holding structure of the liquid crystal display panel 10 in the liquid crystal display device will be described in detail.

As shown in FIG. 1, the liquid crystal display panel 10
Is the backlight unit 12 configured as described above.
And is adjacently opposed to the optical sheet 32. Further, the bezel 14 is formed in a rectangular shape having an opening exposing an effective area of the liquid crystal display panel 10, and is fitted to the holding frame 24 of the backlight unit 12 while covering a peripheral portion of the liquid crystal display panel 10. ing. And
The liquid crystal display panel 10 is held between the bezel 14 and the holding frame 24 by fixing the bezel 14 to the holding frame 24 by screwing.

That is, as shown in FIG. 3, the reflection sheet 28, the light guide 26, the diffusion sheet 30, and the prism sheet 32 are arranged in this order on the receiving surface 24g of the holding frame 24.
Is placed on top. Array substrate 100 and counter substrate 2
The liquid crystal display panel 10 provided with the polarizing plates 190 and 290 on the outer surface of the holding frame 24 is fixed by being adhered to the receiving surface 24h of the holding frame 24 via the double-sided tape 60.

The bezel 14 is fixed to the holding frame 24 by screws 80. As shown in FIG. 3, the structure in which the liquid crystal display panel 10 is sandwiched between the bezel 14 and the holding frame 24 in the vicinity of a screwing portion where the bezel 14 and the holding frame 24 are screwed is formed by a load caused by the screwing. Presses the liquid crystal display panel 10 locally,
Display defects such as a waving phenomenon are likely to occur.

For this reason, the side wall 24 (a, b, c,
A support member 70 that supports the bezel 14 is provided between the bezel 14 and d) so as to form a gap between the bezel 14 and the liquid crystal display panel 10. This support member 70
Has a thickness of, for example, 0.1 mm, and forms a gap of about 0.1 mm between the bezel 14 and the liquid crystal display panel 10 corresponding to the thickness of the support member 70. The support member 70 may be formed integrally with the holding frame 24.

Thus, the bezel 14 is held by the holding frame 2
Even when the screw is screwed to the liquid crystal display panel 4, the bezel 14 does not come into contact with the liquid crystal display panel 10 in the vicinity of the screwed portion, so that the liquid crystal display panel 10 is not locally pressed, and a display defect such as a waving phenomenon is caused. It is possible to prevent occurrence.

As shown in FIGS. 3 to 5, an edge 24j formed on the receiving surface 24h of the holding frame 24 for receiving the liquid crystal display panel 10 is chamfered. The edge 24j is, for example, chamfered in a flat or arc shape over a width of 0.3 mm and a height of 0.3 mm.

Therefore, when a stress such as a twist is applied to the liquid crystal display device from the outside, the holding frame 2
The edge 24j of No. 4 does not locally push up the liquid crystal display panel 10 from the back surface, so that it is possible to prevent a display defect such as a waving phenomenon from occurring.

Further, as shown in FIGS. 4 and 5, the fitting portion 24f has a receiving surface 24h for receiving the liquid crystal display panel 10.
Are covered by rubber spacers 90 arranged along the line. That is, the liquid crystal display panel 10 is disposed on the receiving surface 24h via the rubber spacer at the fitting portion 24f of the holding frame 24.

For this reason, when the liquid crystal display panel 10 is disposed on the receiving surface 24h, the edge 24k formed on the fitting portion 24f of the holding frame 24 has the edge 24k.
There is no direct contact with

The edge 24k formed on the receiving surface 24h of the liquid crystal display panel 10 at the fitting portion 24f where the positioning portion 26f of the light guide 26 fits is chamfered. The edge 24k is, for example, chamfered in a flat or arc shape over a width of 0.3 mm and a height of 0.3 mm, similarly to the above-described edge 24j.

For this reason, even when stress such as twisting is applied to the liquid crystal display device from the outside, the edge 24k formed in the fitting portion 24f is kept in contact with the liquid crystal display panel 1.
0 is not pushed up locally from the back.

Therefore, in the vicinity of the fitting portion 24f,
It is possible to prevent a display defect such as a waving phenomenon from occurring.

As described above, according to the liquid crystal display device of the present invention, even if a bezel or a holding frame whose strength is relatively low is used in order to achieve a reduction in size and weight, it is not necessary to provide an external device. The stress applied to the liquid crystal display panel 10 can be alleviated, and the occurrence of display failure due to the stress can be suppressed.

[0045]

As described above, according to the present invention, it is possible to provide a liquid crystal display device capable of realizing a reduction in thickness and weight and preventing occurrence of display defects.

[Brief description of the drawings]

FIG. 1 is an exploded view schematically showing a structure according to an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is an exploded view schematically showing a structure of a backlight unit of the liquid crystal display device shown in FIG.

FIG. 3 is a sectional view schematically showing a structure near a screwing portion in the liquid crystal display device shown in FIG. 1;

FIG. 4 is a plan view schematically showing a structure around a positioning part and a fitting part in the liquid crystal display device shown in FIG.

FIG. 5 is a perspective view schematically showing a structure around a positioning unit and a fitting unit shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display panel 12 ... Backlight unit 14 ... Bezel 100 ... Array substrate 200 ... Counter substrate 300 ... Liquid crystal layer 24 ... Holding frame 24 (a, b, c, d) ... Side wall 24f ... Fitting part 24 (g, h) receiving surface 24 (j, k) ... edge 26 ... light guide 26 f ... positioning part 60 ... double-sided tape 70 ... support member 90 ... rubber spacer

Claims (5)

[Claims] A liquid crystal display panel having a liquid crystal layer sandwiched between a pair of substrates; a surface light source unit that illuminates the liquid crystal display panel; a first frame that holds the liquid crystal display panel and the surface light source unit; A second frame fixed to the first frame so as to arrange the liquid crystal display panel and the surface light source unit between the second frame and the liquid crystal display; A supporting portion for supporting the second frame so as to form a gap between the panel and the panel; the first frame has a receiving surface for receiving the liquid crystal display panel, and an edge of the receiving surface is chamfered; A liquid crystal display device characterized in that: 2. The liquid crystal display device according to claim 1, wherein the receiving surface of the first frame includes a rubber interposed between the first frame and the liquid crystal display panel. 3. The surface light source section is configured to emit incident light incident from an incident surface provided on one side surface from an exit surface provided on one principal surface crossing the incident surface, and to position the light. A light guide having a positioning portion; a light source disposed to face an incident surface of the light guide; and a liquid crystal panel configured to give predetermined optical characteristics to light emitted from an emission surface of the light guide. The optical sheet which guides to the said 1st frame, The said 1st frame is equipped with the said rubber in the receiving surface of the fitting part periphery which fits into the positioning part of the said light guide, The said rubber | gum is characterized by the above-mentioned. Liquid crystal display device. 4. The liquid crystal display device according to claim 3, wherein an edge of said fitting portion is chamfered. 5. The liquid crystal display device according to claim 1, wherein said support portion is formed integrally with said first frame.