JPH11183903A - Liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high quality picture display by preventing an optical leakage from an outer periphery of a display screen caused by reflection on an inner end face of an upper transparent substrate. SOLUTION: The light is controlled not to pass through a display screen side by preventing reflection of the light made incident on an inner end face of an upper transparent substrate SUB2 from a backlight structure BKL by means of applying a black resin film BEPX to a stuck end edge part of two transparent substrates SUB1, SUB2, especially the end edge part of the upper transparent substrate SUB2, of a liquid crystal panel PNL constituting a liquid crystal display device.

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 liquid crystal layer sealed in a gap between two transparent substrates and a backlight assembly disposed below the liquid crystal display device. The present invention relates to a liquid crystal display device provided at least.

[0002]

2. Description of the Related Art Liquid crystal displays are widely used as devices for displaying various images including still images and moving images.

In a liquid crystal display device constituting this type of liquid crystal display device, a stripe-shaped transparent electrode is arranged on each of two substrates, and the two substrates are opposed to each other with a predetermined gap via a liquid crystal composition. When the stripe-shaped electrodes intersect each other to form a matrix, a pixel is formed at each intersection and a simple matrix type is formed, and an electrode formed on one side of the substrate is separated for each pixel. The active matrix type is provided with an element having a switching function.

An active matrix type liquid crystal display device using an active element typified by a thin film transistor (TFT) has been widely used as a display terminal for OA equipment and the like because of its features of being thin and lightweight and having high image quality comparable to a cathode ray tube. Has begun.

[0005] The display method of this liquid crystal display device is roughly classified into the following two methods. One is a transparent electrode 2
Liquid crystal composition layer (hereinafter, referred to as a transparent glass substrate)
A liquid crystal layer or simply a liquid crystal) is sandwiched, and the molecular orientation of the liquid crystal layer is changed by a voltage applied to the transparent electrode, and light transmitted through the transparent electrode and incident on the liquid crystal is modulated and displayed. Yes, quite a few popular products now use this method.

The other is to change the molecular orientation direction of the liquid crystal layer by a substantially parallel electric field formed on the substrate surface between two electrodes formed on the same substrate, and to change the orientation of the liquid crystal layer from the gap between the two electrodes. This is a method of modulating the light incident on and displaying it.

The former system is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-309921, and the characteristics of the latter system are disclosed in Japanese Patent Publication No. 5-505247 and Japanese Patent Publication No. 63-21907. It is described in.

Each of the above active matrix type liquid crystal display devices includes a switching element corresponding to each of a plurality of pixel electrodes arranged in a matrix. Since the liquid crystal in each pixel is logically driven at all times, the contrast is better than that of a simple matrix type liquid crystal display device driven in a time-division manner, and is particularly indispensable for color display.

In a liquid crystal display device, liquid crystal is basically sealed between two insulating transparent substrates, at least one of which is made of transparent glass or the like, and the periphery of the substrate is bonded and fixed with a sealant. A liquid crystal display element with a liquid crystal layer sandwiched between it and a liquid crystal display element that integrates a drive circuit, a polarizing plate, and various other optical sheets with the liquid crystal display element incorporates a backlight assembly into a metal frame (metallic shield case). ).

FIG. 7 is a partial cross-sectional view for explaining the outline of the main structure of an active matrix type liquid crystal display device.

This liquid crystal display device has an upper transparent substrate SUB2
A liquid crystal panel PNL having a liquid crystal layer LC sandwiched between it and the lower transparent substrate SUB1, a backlight structure BKL, and a frame spacer WSPC interposed between an intermediate frame (mold case) holding the backlight assembly. Metal frame SH
D is integrally fixed and held. In addition, a print on which a drive circuit installed around the liquid crystal panel PNL is mounted, and other components are not shown.

BM is a black matrix, FIL
Denotes a color filter, and POL1 and POL2 denote an upper polarizing plate and a lower polarizing plate adhered to the lower transparent substrate SUB1 and the upper transparent substrate SUB2, respectively. In this liquid crystal display device, the lower transparent substrate SUB1 is a TFT substrate, and the upper transparent substrate SUB2 is a color filter substrate. The details of the color filter and the TFT are omitted.

The two transparent substrates (the lower transparent substrate SUB1 and the upper transparent substrate SUB2) constituting the liquid crystal panel PNL are bonded together at their peripheral edges with a sealing material SL. On the side, a resin film EPX is applied to prevent invasion of moisture and the like and improve the bonding strength. This resin film EPX is generally made of an epoxy resin.

[0014]

In the above configuration,
The metal frame SHD is an outer peripheral edge of the liquid crystal display element PNL,
Although a so-called frame is defined, the dimension from the inner peripheral edge of the metal frame SHD to the effective display area tends to be narrowed with recent narrowing of the frame. Therefore, light incident on the liquid crystal display element PNL from the backlight structure BKL is reflected at the inner edge of the upper transparent substrate SUB2, and this is reflected by the metal frame SNL.
Light leakage LL that escapes from the opening of the HD to the display surface side occurs,
There is a problem that display quality is deteriorated.

An object of the present invention is to provide a high quality liquid crystal display device which solves the above-mentioned problems of the prior art.

[0016]

In order to achieve the above object, the present invention provides a liquid crystal display device comprising a liquid crystal panel and a bonding edge of two transparent substrates, particularly an edge of an upper transparent substrate. By making the resin film applied to the light-absorbing material or a transparent material having a refractive index close to the refractive index of the upper transparent substrate, the reflection of light incident on the inner end face of the upper transparent substrate from the backlight structure is reduced. The light is prevented from leaking to the display surface side.

That is, in order to achieve the above object, the present invention provides the following constitutions (1) to (3) or (4)
(5) is characterized.

(1) A liquid crystal display element having a liquid crystal layer sandwiched in a gap formed by bonding an upper transparent substrate and a lower transparent substrate having at least one side protruding in a plane direction from an edge of the upper transparent substrate; The upper transparent substrate and the lower transparent substrate of the liquid crystal display device in which a backlight assembly is integrated on a side substrate side with a shield case having a display window for forming a display surface around four sides of the upper transparent substrate. A coating film of a light-absorbing substance is formed on at least the end surface of the upper transparent substrate at the bonding end surface, and light from the backlight assembly incident on the inner end surface of the upper transparent substrate is reflected on the display surface side. Was prevented.

(2) The coating film of the light absorbing substance in (1) was made of a resin material mixed with a black dye.

(3) The coating film of the light absorbing substance in (1) is made of a resin material mixed with a black pigment.

The black pigment in the above (2) can be obtained by mixing a known single black dye or a dye of two or more colors with a transparent resin such as an epoxy resin.

As the black pigment in (3), other organic or inorganic black pigments such as carbon or metal oxides can be used alone or as a mixture of two or more pigments.

By adopting the above constitutions (1) to (3),
Light from the backlight assembly incident on the inner end face of the upper transparent substrate is not reflected by the inner end face, and light leakage does not occur on the outer periphery of the display surface, so that high-quality image display can be obtained.

(4) A liquid crystal display element having a liquid crystal layer sandwiched in a gap formed by bonding an upper transparent substrate and a lower transparent substrate having at least one side projecting in a plane direction from an edge of the upper transparent substrate; The upper transparent substrate and the lower transparent substrate of the liquid crystal display device in which a backlight assembly is integrated on a side substrate side with a shield case having a display window for forming a display surface around four sides of the upper transparent substrate. A transparent coating film made of a material having a refractive index similar to that of the upper transparent substrate is formed on at least the end surface of the upper transparent substrate at the bonding end surface, and the backlight assembly is incident on the inner end surface of the upper transparent substrate. Is transmitted through the end surface of the upper transparent substrate to prevent reflection on the display surface side.

(5) The transparent coating film in (4) was made of frit glass.

With the above configurations (4) and (5), light from the backlight assembly incident on the inner end face of the upper transparent substrate is emitted to the transparent coating film side through the inner end face. Light leakage does not occur on the outer periphery of the display surface, and a high-quality image display can be obtained.

The material of the transparent coating film of (1) is not limited to the frit glass of (5) but may be a resin having a refractive index close to the refractive index of the upper transparent substrate.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to examples.

FIG. 1 is a sectional view of a principal part for explaining a first embodiment of the liquid crystal display device according to the present invention. The liquid crystal display device of this embodiment also has a liquid crystal panel PNL having a liquid crystal layer LC sandwiched between an upper transparent substrate SUB2 and a lower transparent substrate SUB1, and a backlight structure BKL, similarly to the conventional liquid crystal display device described with reference to FIG. , Frame spacer WSPC interposed between a backlight assembly and a mold case (not shown) for holding the backlight assembly
Are integrally fixed and held by the metal frame SHD. Note that BM is a black matrix, FIL is a color filter, POL1 and POL2 are upper transparent substrates SUB, respectively.
2. An upper polarizing plate and a lower polarizing plate adhered to the lower transparent substrate SUB1. In this liquid crystal display device, the lower transparent substrate SUB1 is T
The FT substrate and the upper transparent substrate SUB2 are color filter substrates. The details of the color filter and the TFT are omitted. The printed circuit board on which the drive circuit is mounted and other components are not shown.

The upper transparent substrate SUB2 and the lower transparent substrate are bonded with a sealing material SL, and a black resin film BEPX is applied to the bonding edge.

The black resin film BEPX is made by mixing a black dye or a black pigment into an epoxy resin, absorbs light from the backlight assembly BKL indicated by an arrow, and reflects the light on the inner end surface of the upper transparent substrate SUB2. To prevent

Thus, light leakage around the outer periphery of the effective display area (so-called frame) in narrowing the frame can be prevented, and a high quality liquid crystal display device can be provided.

FIG. 2 is a schematic sectional view of a main part of an upper and lower transparent substrate for explaining a second embodiment of the liquid crystal display device according to the present invention.

In this embodiment, as in the first embodiment, the upper transparent substrate SUB2 and the lower transparent substrate are bonded together with a sealing material SL, and a black resin film BEPX is applied to the edges.

The black resin film BEPX is made by mixing a black dye or a black pigment into an epoxy resin, absorbs light from the backlight assembly BKL indicated by an arrow, and reflects the light at the inner end surface of the upper transparent substrate SUB2. To prevent

In this embodiment, since the black resin film BEPX is applied from the bonded end surface of the upper transparent substrate SUB2 to the surface of the lower transparent substrate SUB1, the frame spacer WSPC is connected to the backlight assembly BKL. , And therefore, a portion of the frame spacer WSPC extending in the direction of the display surface as shown in the figure can be shortened or eliminated.

As a result, light leakage around the periphery of the effective display area (so-called frame) in narrowing the frame can be prevented, and a high quality liquid crystal display device can be provided.

FIG. 3 is a schematic sectional view of a main part of a liquid crystal display according to a third embodiment of the present invention.

In this embodiment, as in the above embodiments, the upper transparent substrate SUB2 and the lower transparent substrate are bonded by a sealing material SL, and a black resin film BEPX is attached to the edge of the sealing material SL up to the position of the sealing material SL where the two substrates are bonded. , Ie, filling the gap between the outer circumferences of the two transparent substrates.

The black resin film BEPX is made by mixing a black dye or a black pigment into the epoxy resin as in each of the above embodiments, absorbs light from the backlight assembly BKL indicated by the arrow, and The reflection at the inner end face of SUB2 is prevented.

In this embodiment, since the black resin film BEPX is filled in the gap between the two substrates on the bonding end face of the upper transparent substrate SUB2 up to the position of the sealing material SL, the bonding portion from the backlight BKL Can be blocked, and light leakage around the periphery of the effective display area (a so-called frame) in narrowing the frame can be prevented, and a high-quality liquid crystal display device can be provided.

FIG. 4 is a schematic sectional view of a main part of a liquid crystal display according to a fourth embodiment of the present invention.

In this embodiment, the upper transparent substrate SUB2 and the lower transparent substrate are bonded with a sealing material SL, and frit glass is coated on the edge of the transparent substrate as a light transmitting material having a refractive index close to the refractive index of the upper transparent substrate SUB2. The film FLG is formed.

With this configuration, light incident on the inner end face of the upper transparent substrate SUB2 from the backlight BKL is transmitted to the coating film FLG side of frit glass. Therefore, the reflection of light on the inner end face of the upper transparent substrate SUB2 is significantly reduced, and light leakage on the outer periphery of the effective display area in narrowing the frame is prevented.
A high quality liquid crystal display device can be provided.

FIGS. 5A and 5B are completed views of the liquid crystal display device according to the present invention. FIG. 5A is a plan view of the display surface side, FIG. 5B is a left side view, FIG. 5C is a right side view, and FIG. Upper side, (E)
Shows a lower side view.

In the figure, SHD is a metal frame (upper case), AR is a display area (display surface), MCA is a lower frame (lower case), HLDs 1 to 4 are mounting holes,
LCT is a connection connector, LPC1 and LPC2 are lamp cables, CT1 is an interface connector, and WD is an opening exposing a display area. POL2 is affixed to the upper surface (display surface) of the liquid crystal panel PNL with an upper polarizing plate.

This liquid crystal display device has a metal frame SH
D and the lower frame MCA are incorporated using two types of storage / holding members, and are mounted on display portions of an information processing device such as a notebook computer or a monitor through the mounting holes HLD1 to HLD4.

A backlight inverter is incorporated in the recess between the mounting holes HLD1 and HLD3, and the connector LCT and the lamp cables LPC1, LPC2
Supplies power to the cold cathode fluorescent lamp (light source lamp) constituting the backlight assembly. In this example, the fluorescent tubes are incorporated on the upper and lower sides of the back of the liquid crystal display element PNL.

Signals from the main body computer (host) and necessary power are supplied through an interface connector CT1 located on the back surface.

The liquid crystal display device shown has a large outer diameter,
The so-called frame area that does not contribute to the display is small despite the display area AR also being large. Light leakage from the outer periphery of the display surface is suppressed by the configuration described in the above embodiment. Furthermore, the weight is also reduced, and a large-screen display that is easy to view without losing the portability of the portable information processing device can be obtained.

FIG. 6 is an explanatory view of a portable notebook personal computer as a typical example of an information processing apparatus using the liquid crystal display device according to the present invention.

In this notebook computer, a keyboard section and a display section are connected by a hinge. The keyboard section incorporates a CPU serving as a host computer, and the display section is mounted with a liquid crystal display device according to the present invention.

The liquid crystal display device mounted on the display unit includes a liquid crystal panel PNL, a scanning signal line side flexible printed circuit board FPC1, and a video signal line side flexible printed circuit board FP.
Drive circuit board such as C2, interface board PCB,
It is composed of an inverter power supply IV and the like. LPC is a lamp cable for supplying power from the inverter power supply IV to the fluorescent tubes constituting the backlight assembly.

Since the liquid crystal display device of the notebook personal computer employs the structure described in each of the above embodiments, there is no light leakage from the outer periphery of the effective display area and high quality image display is possible.

The present invention is not limited to the active matrix type liquid crystal display device described above, but can be similarly applied to a simple matrix type and other liquid crystal display devices.

[0056]

As described above, according to the present invention,
Obtaining a liquid crystal display device in which light leakage from the outer periphery of the display surface due to reflection from the inner end surface of the upper transparent substrate of the two transparent substrates constituting the liquid crystal panel is suppressed and high quality image display is possible Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of a principal part for explaining a first embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a schematic cross-sectional view of main parts of upper and lower transparent substrates for explaining a second embodiment of the liquid crystal display device according to the present invention.

FIG. 3 is a schematic cross-sectional view of a principal part explaining a third embodiment of the liquid crystal display device according to the present invention.

FIG. 4 is a schematic cross-sectional view of a principal part explaining a fourth embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is an assembled view of the liquid crystal display device according to the present invention.

FIG. 6 is an explanatory diagram of a portable notebook personal computer as a typical example of an information processing device using a liquid crystal display device according to the present invention.

FIG. 7 is a partial cross-sectional view schematically illustrating a configuration of a main part of an active matrix liquid crystal display device.

[Explanation of symbols]

 SUB1 Lower transparent substrate SUB2 Upper transparent substrate PNL Liquid crystal panel BKL Backlight assembly LC Liquid crystal layer WSPC Frame spacer BM Black matrix FIL Color filter POL1 Lower polarizing plate POL2 Upper polarizing plate BEPX Black resin film FLG Frit glass coating SHD metal frame.

Claims (5)

[Claims] A liquid crystal display element having a liquid crystal layer sandwiched in a gap in which an upper transparent substrate and a lower transparent substrate having at least one side projecting in a plane direction from an edge of the upper transparent substrate are bonded to each other; In a liquid crystal display device in which a backlight assembly is integrated on a substrate side with a shield case having a display window for forming a display surface around four sides of the upper transparent substrate, the upper transparent substrate and the lower transparent substrate A coating film of a light-absorbing substance is formed on at least the end surface of the upper transparent substrate at the bonding end surface, and light from the backlight assembly incident on the inner end surface of the upper transparent substrate is reflected on the display surface side. A liquid crystal display device characterized by preventing the occurrence of the liquid crystal display. 2. The liquid crystal display device according to claim 1, wherein the coating film of the light absorbing substance is a resin material mixed with a black dye. 3. The liquid crystal display device according to claim 1, wherein the coating film of the light absorbing substance is a resin material mixed with a black pigment. 4. A liquid crystal display device having a liquid crystal layer sandwiched in a gap in which an upper transparent substrate and a lower transparent substrate having at least one side projecting in a plane direction from an edge of the upper transparent substrate are bonded to each other. In a liquid crystal display device in which a backlight assembly is integrated on a substrate side with a shield case having a display window for forming a display surface around four sides of the upper transparent substrate, the upper transparent substrate and the lower transparent substrate A transparent coating film of a material having a refractive index similar to that of the upper transparent substrate is formed on at least the end surface of the upper transparent substrate at the bonding end surface, and the backlight assembly is incident on the inner end surface of the upper transparent substrate. A liquid crystal display device, wherein the light is transmitted through an end surface of the upper transparent substrate to prevent the light from being reflected on the display surface side. 5. The liquid crystal display device according to claim 4, wherein said transparent coating film is frit glass.