JP2009116204A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of realizing both improvement in display quality and yield by filling a gel-like translucent gel substance between a translucent protective plate and a liquid crystal display panel.
A liquid crystal display device having a liquid crystal display panel, a backlight device, and a mold frame for housing them, and a translucent protective plate is disposed on the front surface of the liquid crystal display panel. The frame 9 has a peripheral portion extending in the height direction to accommodate a liquid crystal display panel, and a translucent protective plate 4 is disposed on the peripheral portion. A portion between the panel 1 and the translucent protective plate 4 has an inlet 12 a and an outlet 12 b for the translucent gel substance, and is provided between the liquid crystal display panel 1 and the translucent protective plate 4. Is that a translucent gel substance is arranged.
[Selection] Figure 1

Description

  The present invention relates to a liquid crystal display device, and more particularly to a configuration in the case where a translucent material is disposed between a liquid crystal display panel and a translucent protective plate disposed in front of the liquid crystal display panel.

  A liquid crystal display panel constituting a liquid crystal display device basically includes a pixel having a liquid crystal layer sealed between two substrates, a first substrate and a second substrate, which are preferably glass substrates. This is an image display device utilizing the fact that the orientation direction of the liquid crystal changes according to the electric field applied to the liquid crystal from the selection electrode. Currently, the most widely used all-transmission type liquid crystal display device polarizes the light source light projected from the backlight device installed on the back side of the liquid crystal display panel by about 90 degrees in the liquid crystal layer and transmits it through the polarizing plate. By doing so, the electronic imaging can be visually recognized as a visible image.

  In a liquid crystal display device using a non-light emitting liquid crystal display panel, electronic imaging formed on the liquid crystal display panel is visualized by providing external illumination means. Except for the structure using natural light, the external illumination means is provided with an illumination device on the back or front of the liquid crystal display panel. Especially for display devices that require high brightness, a structure in which an illuminating device is provided on the back of a liquid crystal display panel has become the mainstream. This is called a liquid crystal display device using a transmissive liquid crystal display panel.

  Currently, a so-called direct-type backlight device in which a plurality of CCFLs or EEFLs are arranged directly under a liquid crystal display panel is used for a transmissive liquid crystal display panel used in a large liquid crystal display device for TV. A transmissive liquid crystal display panel used for a small liquid crystal panel such as a mobile phone or a digital still camera has an optical sheet such as a diffusion sheet or a prism sheet on the lower surface of the liquid crystal display panel, and a light source such as an LED on the side surface. A so-called sidelight type backlight device in which a light guide plate is disposed is used.

  In the liquid crystal display device using the sidelight type backlight device described above as an illumination light source, the liquid crystal display panel is formed of a resin in order to realize a narrow frame, light weight, and integration of the liquid crystal display panel. An optical sheet and a light guide plate are disposed above the frame-shaped mold frame, and a reflection sheet disposed under the light guide plate is attached to the mold frame from below.

  When a liquid crystal display panel is used as a liquid crystal display device of a cellular phone, the cellular phone is provided with a translucent protective plate made of an acrylic plate, for example, on the upper side of the liquid crystal display panel. Is protecting.

  When the cellular phone configured in this way is used outdoors, there is a space layer (air layer) between the translucent protective plate and the liquid crystal display module, so external light is incident on the display surface and diffusely reflected. As a result, mirror reflection occurs and a sufficiently satisfactory display quality cannot be obtained.

  This problem arises because an air layer exists between the translucent protective plate and the liquid crystal display panel, and the refractive index of the translucent protective plate and the refractive index of the air layer are different. Therefore, it is considered that this problem can be solved by disposing a substance having a refractive index substantially equal to that of the translucent protective plate instead of the air layer. For example, when the translucent protective plate is formed of an acrylic plate, A method of arranging an elastomer having substantially the same refractive index as that of an acrylic plate is considered. Elastomers are highly versatile. For example, by disposing a film-like elastomer, irregular reflection due to external light can be greatly suppressed.

  This configuration is specifically shown. In this configuration, an acrylic plate is used as the translucent protective plate. FIG. 5A is a development view of the main part, and FIG. 5B is a top view of the main part. As shown in FIGS. 5A and 5B, a driving circuit chip 1a is mounted on the liquid crystal display panel 1, and a flexible printed circuit board 1b electrically connected to an external circuit is coupled to the liquid crystal display module 2. Is configured. In addition, a film-like elastomer 3 is disposed on the front side of the liquid crystal display module 2 by bonding, and a translucent protective plate 4 is adhered to the outer peripheral edge of the elastomer 3 with a double-sided tape or the like, for example. It is configured by bonding together. In the drawing, the backlight device and the like are omitted.

  As described above, when the film-like elastomer 3 is used between the translucent protective plate 4 and the liquid crystal display panel 1, either the translucent protective plate 4 or the liquid crystal display panel 1 is attached to the elastomer 3. Although the attaching workability is high, when the other is attached, the translucent protective plate 4 and the liquid crystal display module 2 are both hard, so the attaching workability is poor. For this reason, as shown in FIG. It has been found that there is a problem that the yield of appearance is reduced due to the mixing of bubbles 5 in 4a.

  Further, when the film-like elastomer 3 has a complicated uneven structure on the front and back surfaces thereof, between the translucent protective plate 4 and the film-like elastomer 3 and between the film-like elastomer 3 and the liquid crystal display panel 1. It was found that a sufficient degree of adhesion was not obtained, and bubbles 5 having a large shape were mixed, resulting in problems in appearance yield and display quality.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a liquid crystal display device capable of realizing both improvement in display quality and yield.

  According to one embodiment of the present invention, a liquid crystal display panel, a backlight device installed on the back surface of the liquid crystal display panel, and a mold frame for housing the liquid crystal display panel and the backlight device are provided. In the liquid crystal display device, a translucent protective plate made of, for example, an acrylic substrate or a glass substrate is disposed on the front surface of the liquid crystal display panel, and the mold frame extends the peripheral portion in the height direction to display the liquid crystal display. The panel is housed, and a translucent protective plate is disposed at the upper part of the peripheral portion thereof, and the portion between the liquid crystal display panel and the translucent protective plate on the peripheral portion of the mold frame is not transparent. It has an inlet and an outlet for the light gel material, and the light transmitting gel material is disposed between the liquid crystal display panel and the light transmitting protective plate.

  With such a configuration, it is possible to provide a liquid crystal display device capable of suppressing a reduction in display quality caused by external light irregular reflection.

  As an example, the light-transmitting gel substance is preferably a gel-like elastomer, and the light-transmitting protective plate is preferably a light-transmitting acrylic plate or a light-transmitting glass substrate.

  In the present invention, when the liquid crystal display panel has a quadrangular shape, the peripheral edge of the mold frame is formed at a location corresponding to the three sides of the liquid crystal display panel, and one side where the peripheral edge of the liquid crystal display panel is not formed. A cushioning material is arranged in the case. The cushion material is desirably formed up to the same position as the peripheral edge. Another feature of the present invention is that the peripheral edge is formed up to a position higher than the liquid crystal display panel.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display device which can suppress the display quality fall resulting from external light irregular reflection can be provided.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is an exploded perspective view for explaining the configuration of a liquid crystal display device according to Embodiment 1 of the present invention. FIG. 2 is a side view of the liquid crystal display device according to the first embodiment.

  In FIG. 1, a liquid crystal display panel 1 is configured by enclosing a liquid crystal layer between a pair of translucent substrates such as a glass substrate. The liquid crystal display panel 1 is connected to a flexible printed circuit board 1b on which a driving circuit chip 1a for driving a liquid crystal layer is mounted on a part of the glass substrate, and an external driving circuit and a light source 13 such as an LED are arranged. ing. The liquid crystal display panel 1 is accommodated in a mold frame 9 made of resin or the like. The mold frame 9 has a frame-like shape with a window 91 at the center, the liquid crystal display panel 1 is disposed on the upper side, and the optical sheet such as the light guide plate 14, a diffusion sheet, and a prism sheet is disposed on the lower side. Become.

  In addition, the light guide plate 14 etc. are hold | maintained by sticking the peripheral part of the reflective sheet arrange | positioned under the light guide plate 14 to the mold frame 9 with a double-sided tape or an adhesive agent. Note that the flexible printed circuit board 1b is disposed so that the portion where the light source 13 such as an LED is disposed is close to the light incident surface of the light guide plate 14 so as to be wound around the mold frame 9. In the first embodiment, a configuration of a so-called COG type liquid crystal display panel in which the drive circuit chip 1a is mounted on the glass substrate will be described. However, the present invention is not limited to the arrangement position of the drive circuit chip 1a. The present invention can also be applied to a so-called COF type liquid crystal display device in which a chip is arranged on a film.

  In addition, on the front side of the liquid crystal display panel 1, a translucent protective plate 4 such as an acrylic plate for protecting the display surface of the liquid crystal display panel 1 is disposed.

  FIG. 2 is a drawing for explaining the configuration when the components described in FIG. 1 are actually housed in the mold frame 9. As shown in FIG. 2, the liquid crystal display panel 1 is disposed on the upper side of the mold frame 9, and the optical sheet 10 and the light guide plate 14 are disposed on the lower side of the mold frame 9, The reflection sheet 8 is bonded to the mold frame 9.

  FIG. 3 is a perspective view showing a state in which the liquid crystal display panel 1 is housed in the mold frame 9. As shown in FIG. 3, in the mold frame 9, the height t <b> 2 of the peripheral edge 9 a on the three sides excluding the flexible printed circuit board 2 b connected to the liquid crystal display panel 1 is the height in the thickness direction of the liquid crystal display panel 1. The height is higher than t1. That is, the peripheral edge 9 a has a shape that is higher in height (thickness) direction than the display surface of the liquid crystal display panel 1. In the drawing, the translucent protective plate 4 is omitted.

  Further, on the flexible printed circuit board 1b side of the liquid crystal display panel 1 on the mold frame 9, a cushion material 11 formed of, for example, rubber having a height substantially equal to the height t1 of the peripheral edge portion 9a is not shown. Is adhered and arranged. Therefore, the liquid crystal display panel 1 is surrounded by the peripheral edge portion 9a and the cushion material 11.

  A frame-like double-sided tape 12 is disposed on the peripheral edge 9a of the mold frame 9 and the upper surface of the cushion material 11, and the translucent protective plate 4 made of, for example, acrylic, the peripheral edge 9a of the mold frame 9, and the cushion material 11 And place them together. The present invention is also characterized in that an injection port 12a and a discharge port 12b into which a light-transmitting gel-like substance, which will be described later, is poured are formed in the peripheral portion 9a of the mold frame 9. With such a configuration, a sealed space layer is formed between the translucent protective plate 4 and the liquid crystal display panel 1 and communicates with the outside air via the inlet 12a and the outlet 12b.

  Thereafter, as shown in FIG. 4, a translucent gel-like substance (eg, gel-like elastomer) is injected from the inlet 12a in a vacuum atmosphere, and excess air and gel-like substance are discharged from the outlet 12b. To do. As a result, a light-transmitting gel-like substance is filled between the liquid crystal display panel 1 and the light-transmitting protective plate 4, and thereafter, the injection port 12a and the discharge port 12b are formed using, for example, an epoxy-based or silicon-based sealing material. Seal. The translucent gel-like substance preferably has a refractive index equivalent to that of the translucent protective plate 4 (a material that is within ± 5% in the present invention). For example, the translucent protective plate 4 When an acrylic material is used, a gel-like elastomer can be used as the translucent gel-like substance.

  According to such a configuration, since the light-transmitting gel-like substance is filled between the light-transmitting protective plate 4 and the surface of the liquid crystal display panel 1, it is possible to suppress deterioration in display quality due to external light irregular reflection. can do. Moreover, sufficient adhesion is obtained between the translucent protective plate 4 and the translucent gel substance, and between the liquid crystal display panel 1 and the translucent gel substance, and a sheet-like translucent member is obtained. Air bubbles are less likely to be mixed as compared with the case of attaching. Furthermore, entry of foreign matter between the translucent protective plate 4 and the liquid crystal display panel 1 is also suppressed.

  Moreover, according to such a structure, since the transparent protective plate 4 is supported by the whole contact part of a translucent gel substance, it becomes effective also with respect to a vibration resistance and a drop impact.

  At present, an epoxy resin or a silicon resin is applied to the terminal portion of the liquid crystal display module 2 for the purpose of preventing electrolytic corrosion. However, according to the configuration of the first embodiment, it can be shared. Therefore, the cost can be reduced by reducing the number of parts.

1 is an exploded perspective view showing a configuration of an embodiment of a liquid crystal display device according to the present invention. 2 is a diagram illustrating a configuration when each component described in FIG. 1 is actually housed in a mold frame 9. FIG. It is a perspective view which shows the state in which the liquid crystal display panel was accommodated in the mold frame. It is drawing which shows the state of injection | pouring and exhaust_gas | exhaustion of a translucent gel-like substance. It is a figure which shows the structure of the conventional liquid crystal display device, Fig.5 (a) is a principal part expansion perspective view, FIG.5 (b) is the principal part top view seen from upper direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display panel, 1a ... Drive circuit chip, 1b ... Flexible printed circuit board, 2 ... Liquid crystal display module, 3 ... Film-like elastomer, 4 ... Translucent protective plate 4a ... display surface, 5 ... air bubbles, 6 ... double-sided tape, 7 ... backlight device, 8 ... reflective sheet, 9 ... mold frame, 9a ... peripheral edge, DESCRIPTION OF SYMBOLS 91 ... Window part, 10 ... Optical sheet, 11 ... Cushion material, 12a ... Injection port, 12b ... Discharge port, 13 ... Light source, 14 ... Light guide plate.

Claims (7)

A liquid crystal display panel;
A backlight device installed on the back of the liquid crystal display panel;
In the liquid crystal display device comprising the liquid crystal display panel and a mold frame that houses the backlight device,
A translucent protective plate is disposed on the front surface of the liquid crystal display panel,
The mold frame includes a liquid crystal display panel that extends in the height direction at the periphery, and the translucent protective plate is disposed on the periphery.
The portion between the liquid crystal display panel and the light-transmissive protective plate at the peripheral edge of the mold frame has a light-transmitting gel substance inlet and outlet,
A liquid crystal display device, wherein a translucent gel substance is disposed between the liquid crystal display panel and the translucent protective plate. The liquid crystal display device according to claim 1.
The liquid crystal display device, wherein the translucent gel substance is a gel-like elastomer. The liquid crystal display device according to claim 1 or 2,
The light-transmitting protective plate is a light-transmitting acrylic plate. The liquid crystal display device according to claim 1 or 2,
The light-transmitting protective plate is a light-transmitting glass substrate. The liquid crystal display device according to any one of claims 1 to 4,
The liquid crystal display panel has a rectangular shape,
The periphery of the mold frame is formed at a location corresponding to the three sides of the liquid crystal display panel,
A liquid crystal display device, wherein a cushion material is disposed on one side of the liquid crystal display panel where the peripheral edge portion is not formed. The liquid crystal display device according to claim 5.
The liquid crystal display device, wherein the cushion material is formed up to the same position as the peripheral edge. In the liquid crystal display device according to any one of claims 1 to 6,
The liquid crystal display device, wherein the peripheral portion is formed to a position higher than the liquid crystal display panel.

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