KR20070069835A - Liquid crystal display device - Google Patents

Abstract

A liquid crystal display device is provided to surround a liquid crystal panel by using an element such as a top case or a support main of a backlight assembly for preventing leakage of light caused by liquid crystal alignment in an unintended direction in a compensation film. A liquid crystal display device includes a liquid crystal panel formed of a color filter layer array substrate(121), a TFT array substrate(111) and a liquid crystal layer(131) between the substrates, and defined into an array part for displaying images and peripheral parts thereof. A compensation film(151) is inserted into the liquid crystal panel and has anisotropic characteristics for UV(Ultra Violet) radiation. An element(200) prevents leakage of light caused by ununiform UV radiation for the compensation film. A backlight assembly is mounted at a lower part of the liquid crystal panel for supplying light thereto. A bottom case supports the liquid crystal panel and the backlight assembly. A top case is attached to an outside of the bottom case and surrounds edges of the liquid crystal panel to serve as the element for preventing leakage of light.

Description

Liquid Crystal Display Device

1 is a cross-sectional view of an IPS mode liquid crystal panel according to the prior art.

2 is a schematic cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention.

3 is a cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention.

4 is a schematic cross-sectional view of a liquid crystal display according to a third embodiment of the present invention.

5 is a cross-sectional view of a liquid crystal display device according to a fourth embodiment of the present invention.

* Explanation of symbols on the main parts of the drawings

3: bottom-case 4: top-case

11: light emitting lamp 12: lamp housing

13: light guide plate 18: support main

111 TFT array substrate 121 color filter layer array substrate

131: liquid crystal layer 151: compensation film

153: upper polarizing film 154: lower polarizing film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device (LCD), and in particular, liquid crystals dispersed in a compensation film are arranged in an undesired direction so that light leakage occurs at an outer edge of the array. The present invention relates to a liquid crystal display device for completely blocking light leakage.

In recent years, active matrix liquid crystal displays have been widely used in flat panel TVs, portable computers, monitors, and the like, as their performance is rapidly developed.

Among the active matrix liquid crystal display devices, a twisted nematic (TN) type liquid crystal display device is mainly used. In the twisted nematic method, electrodes are installed on two substrates and the liquid crystal directors are arranged to be twisted by 90 degrees. It is a technique of driving a liquid crystal director by applying a voltage to an electrode.

Twisted nematic liquid crystal display devices are in the spotlight for providing excellent contrast and color reproducibility, but suffer from the chronic problem of narrow viewing angles.

In order to solve the viewing angle problem of the TN method, an IPS mode (In-Plane Switching Mode) for forming two electrodes on one substrate and controlling the director of the liquid crystal with a transverse electric field generated between the two electrodes has been introduced.

The IPS mode liquid crystal panel is divided into an array portion on which an image is displayed and an array outer portion of an outer portion thereof, and as illustrated in FIG. 1, color filter layer array substrates disposed opposite to each other and having a liquid crystal layer 31 therebetween. 21 and the TFT array substrate 11. At this time, a sealant 26 is formed at the edge of the substrate to serve as an adhesive to completely bond the two substrates.

That is, the color filter layer array substrate 21 has a black matrix 22 to prevent light leakage, a color filter layer 23 of R, G, and B to implement color, and a step eliminated by a color filter layer. An overcoat layer 24 for planarization is formed. In this case, since the color filter layer 23 is formed to implement color in the image, the color filter layer 23 is limited to the array unit where the image is displayed.

In the TFT array substrate 11, a gate wiring (not shown) and a data wiring 15 defining unit pixels are interposed with a thin film transistor TFT formed at an intersection point of the gate wiring and the data wiring. The common electrode 25 and the pixel electrode 17 which cross and generate a transverse electric field are formed.

In this case, the pixel electrode 17 passes through the passivation layer 16 and is connected to the drain electrode 15b of the thin film transistor TFT to receive a voltage, and the common electrode 25 is integrally connected to the active region. It receives voltage from the outside.

In this manner, the IPS mode liquid crystal panel forms the common electrode 24 and the pixel electrode 17 on the same substrate, and applies a voltage between the two electrodes to generate a horizontal electric field E with respect to the substrate. The liquid crystal molecules are rotated while being kept horizontal with respect to the substrate.

In this case, upper and lower polarizing films 53 and 54 are attached to the TFT array substrate 11 and the color filter layer array substrate 21 to transmit only light having a specific wavelength, respectively, and the color filter layer array substrate 21 and the color filter layer array substrate 21. A compensation film 51 is further provided between the liquid crystal layers 31 to compensate for the phase change of light according to the visual direction.

At this time, the compensation film 51 is characterized in that the C plate compensation film or A plate compensation film, A plate compensation film 52 is made of a liquid crystal material having a negative dielectric constant to compensate for the phase in the horizontal direction The C plate compensation film 51 is made of a liquid crystal material having a positive dielectric constant, and serves to compensate for the phase in the vertical direction.

In general, the IPS mode liquid crystal panel compensates for phase by using a biaxial film or two compensation films, A plate compensation film and C plate compensation film.

Meanwhile, the compensation film may be attached to the outer surface of the color filter layer array substrate 21, but may also be formed between the liquid crystal layer 31 and the color filter layer array substrate 21 as illustrated in FIG. 1. It is formed by coating and curing a polymer in which a liquid crystal is dispersed.

Specifically, the polymer in which the liquid crystal is dispersed is coated on a substrate and then irradiated with ultraviolet rays to cure. A magnetic field is applied during the curing process by ultraviolet rays so that the liquid crystal dispersed in the polymer is arranged in the direction of the magnetic field. The light passing through the compensation film by the liquid crystal array has a predetermined phase difference due to the interaction of the liquid crystal and the polymer.

Such a liquid crystal panel needs a light source for providing light, and a backlight assembly is further mounted on the lower surface of the liquid crystal panel. The liquid crystal panel and the backlight assembly are supported by the bottom-case at the bottom and the top-case at the top.

However, the conventional liquid crystal display device having the above configuration has the following problems.

In order to form the compensation film inside the liquid crystal cell, before or after forming various wirings and electrodes, a polymer in which the liquid crystal is dispersed is coated on the entire surface of the substrate and cured by irradiating ultraviolet rays. Since the array unit is focused and irradiated with ultraviolet rays, the liquid crystals inside the compensation film at the outer edge of the array are arranged in an undesired direction.

In addition, due to the color filter layer limited to the array portion, the level difference between the array portion and the outer portion of the array portion is uneven, and the amount of ultraviolet irradiation applied to the surface is changed by the uneven surface level, and thus the liquid crystal inside the compensation film The arrangement direction is different.

Therefore, the light passing through the compensation film outside the array, as shown in Figure 1, is passed in an undesired direction to appear as a light leakage.

In some cases, in order to bond the substrate, the other layer, and the compensation film, mask the outer edge of the array with a mask and irradiate ultraviolet rays. Inner liquid crystal array direction becomes uneven and light leakage occurs at the outer edge of the array.

The present invention has been made in order to solve the above problems, the liquid crystal dispersed in the compensation film is arranged in an undesired direction to generate light leakage on the outer edge of the array, it is a mechanism to surround the liquid crystal panel completely block the light leakage It is an object of the present invention to provide a liquid crystal display device which is intended to be.

The liquid crystal display device of the present invention for achieving the above object is composed of a liquid crystal layer formed between the first substrate, the second substrate and the first and second substrates, and divided into an array portion and an outer portion where an image is displayed. A liquid crystal panel, a compensation film inserted into the liquid crystal panel and having anisotropy by ultraviolet irradiation, a mechanism to block light leakage caused by uneven ultraviolet irradiation of the compensation film, and a lower portion of the liquid crystal panel. And a backlight assembly for providing light to the liquid crystal panel, a bottom case supporting the liquid crystal panel and the backlight assembly, and a top case attached to an outside of the bottom case and surrounding an edge of the liquid crystal panel. It is done.

That is, a compensation film is formed between the liquid crystal layer and the substrate in order to compensate for light leakage due to the birefringence characteristic of the liquid crystal molecules. The ultraviolet rays are irradiated to cure the compensation film and to arrange liquid crystals dispersed in the compensation film in a predetermined direction. Bars, due to the step and the process due to the uneven UV irradiation amount of the array portion and the array outer portion causes light leakage on the outer edge of the array, the present invention is characterized in that the light leakage defect is completely blocked using a mechanism surrounding the liquid crystal panel.

The upper part of the liquid crystal panel may be extended to the outer edge of the array, or the lower part of the liquid crystal panel may be extended to the outer edge of the array to block light leakage. The instrument may be a support main of the top case or the backlight assembly. will be.

Hereinafter, a liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention, FIG. 3 is a cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 4 is a third embodiment of the present invention. Is a schematic cross-sectional view of a liquid crystal display device, and FIG. 5 is a cross-sectional view of a liquid crystal display device according to a fourth embodiment of the present invention.

The liquid crystal panel according to the present invention can be divided into an array portion where an image is displayed and an outer portion thereof. As shown in FIG. 2, a color filter layer array substrate on which a black matrix and color filter layers of R, G, and B are formed ( 121 and a TFT array substrate 111 on which patterns such as gate wiring, data wiring, thin film transistor, common electrode, and pixel electrode for displaying an image are formed on an inner surface facing the color filter layer array substrate 121. And a liquid crystal layer 131 formed between the color filter layer array substrate 121 and the TFT array substrate 111 that are opposed to each other by a sealant acting as an adhesive, and the color filter layer array substrate 121 and the liquid crystal. The compensation film 151 is further formed between the layers 131.

The liquid crystal layer 131 has birefringence having different refractive indices in the long axis direction and short axis direction of the molecules. The birefringence causes a difference in refractive index depending on the position at which the liquid crystal display device is viewed. When the polarization state is changed, a phase difference occurs, and the amount of light when viewed from a position away from the front and the amount of light when viewed from the front are changed. Accordingly, in the liquid crystal display device using the liquid crystal material, a phenomenon such as change in contrast ratio, color shift, gray inversion, and the like may occur depending on the viewing angle, and light leakage may occur undesirably.

In order to solve this problem, a phase difference compensation film is used as a method of compensating for phase difference generated in the liquid crystal panel. The compensation film 151 according to the present invention is formed by coating a polymer in which liquid crystal is dispersed and curing with ultraviolet rays. When irradiated with ultraviolet light, the liquid crystal dispersed in the polymer is arranged in a predetermined direction, characterized in that anisotropy is provided.

In this case, the apparatus 200 is disposed on the liquid crystal panel, that is, the color filter layer array substrate 121, to completely block the backlight light B / L passing through the array outer portion A. The light leakage of the array outer portion A caused by the non-uniformity of the liquid crystal dispersed in the compensation film is also blocked at the same time.

As the apparatus, as illustrated in FIG. 3, light leakage by the compensation film may be blocked by using the top-case 4.

Specifically, as shown in FIG. 3, the liquid crystal display includes a liquid crystal panel and a backlight assembly in which a gap between the liquid crystal panel is uniform with respect to the front surface to provide light to the liquid crystal panel, and the liquid crystal panel and the backlight. A bottom case 3 supporting the assembly and a top case 4 made of stainless steel, which is attached to the outside of the bottom case 3 and is surrounded by an edge except for an effective area where an image is displayed, the top -Extend the case to the outside of the array (A) to cover the light leakage by the compensation film.

In this case, the liquid crystal panel includes a color filter layer array substrate 121, a TFT array substrate 111, and upper and lower polarizing films 153 and 154 attached to outer surfaces of the two substrates.

Meanwhile, in order to prevent light leakage caused by the compensation film 151, as shown in FIG. 4, the backlight 200 passes through the array outer portion A by arranging the fixture 200 under the TFT array substrate 111. (B / L) can be completely blocked. Thus, light leakage is prevented by blocking the backlight light passing through the array outer portion A in advance.

As the apparatus, as shown in FIG. 5, light leakage by the compensation film may be blocked by using the support main 18, which is a component of the backlight assembly.

Specifically, as shown in FIG. 5, the LCD includes a color filter layer array substrate 121, a TFT array substrate 111, and upper and lower polarizing films 153 and 154 attached to outer surfaces of the two substrates. A liquid crystal panel and a backlight assembly for providing light to the liquid crystal panel with a gap between the liquid crystal panel and the gap between the liquid crystal panel, a bottom case 3 and a top case supporting the liquid crystal panel and the backlight assembly. 4) the support main 18, which is a component of the backlight assembly, extends to the outer edge of the array A to cover the light leakage by the compensation film.

At this time, the backlight assembly is installed on the left or right side of the liquid crystal panel, the light emitting lamp 11 to provide light, the light emitting lamp 11 is fixed and at the same time light from the light emitting lamp 11 light guide plate 13 A lamp housing 12 for concentrating the light, a light guide plate 13 for supplying the light emitted from the light emitting lamp 11 to the liquid crystal panel above the backlight, and a light guide plate 13 attached to the lower part of the light guide plate 13, A reflecting plate 14 reflecting the emitted light to the light guide plate 13, a diffusion sheet 15 positioned above the light guide plate 13 to uniformly diffuse the light emitted from the light guide plate 13, and the diffusion sheet ( 15) a prism sheet 16 positioned above and condensing the light diffused by the diffuser to be transmitted to the liquid crystal panel, a protective sheet 17 protecting the prism sheet 16 on the prism sheet 16; To receive the components It is composed of a support main 18 for fixing.

Here, the photo main 18 is extended between the protective sheet 17 and the lower polarizing film 154 of the liquid crystal panel to the outer edge of the array to cover the light leakage by the compensation film.

As such, when the in-cell coatable type compensation film is directly formed on the liquid crystal panel, the present invention completely prevents light leakage, which may be caused by non-uniformity of UV irradiation, through the mechanism surrounding the liquid crystal panel. It is characterized by blocking.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

That is, the above embodiment has been described in that the compensation film is inserted between the color filter layer array substrate and the liquid crystal layer. However, the present invention is not limited thereto, and the present invention may be applied even when the compensation film is inserted between the TFT array substrate and the liquid crystal layer. Could be. That is, a compensation film is formed by coating a polymer in which a liquid crystal is dispersed between a TFT array substrate and a liquid crystal layer and irradiating ultraviolet rays to determine the alignment direction of the liquid crystal. In order to block it, a device (ex, support main, top case) surrounding the liquid crystal panel is used.

The liquid crystal display according to the present invention as described above has the following effects.

That is, the liquid crystal dispersed in the compensation film is arranged in an undesired direction to generate light leakage, and thus, the light leakage caused by the compensation film may be completely blocked by utilizing a mechanism surrounding the liquid crystal panel.

The instrument may be a mechanism that can block light such as a top case and a main support, and the instrument may be easily extended to an outer portion of the array where light leakage occurs, thereby easily preventing light leakage by a compensation film.

Claims (13)

A liquid crystal panel composed of a first substrate, a second substrate, and a liquid crystal layer formed between the first and second substrates, and divided into an array portion on which an image is displayed and an outer portion thereof; A compensation film inserted into the liquid crystal panel and having anisotropy by ultraviolet irradiation; A device for blocking light leakage caused by uneven ultraviolet irradiation of the compensation film; A backlight assembly mounted below the liquid crystal panel to provide light to the liquid crystal panel; A bottom case supporting the liquid crystal panel and the backlight assembly; And a top-case attached to an outside of the bottom-case and surrounding an edge of the liquid crystal panel. The method of claim 1, And disposing the fixture on the liquid crystal panel to block light leakage caused by the compensation film. The method of claim 1, And the instrument is the top-case. The method of claim 3, wherein And the top-case extends to an outer edge of the array of the liquid crystal panel. The method of claim 1, And disposing the fixture under the liquid crystal panel to block light leakage caused by the compensation film. The method of claim 1, The backlight assembly, A light emitting lamp providing light to the liquid crystal panel; Optical sheets for supplying light emitted from the light emitting lamp to the liquid crystal panel, A reflector for reflecting light leaking toward the opposite side of the liquid crystal panel; And a support main for accommodating and fixing the components. The method of claim 6, And said instrument is a support main of said backlight assembly. The method of claim 7, wherein And the support main extends to the outer edge of the array between the liquid crystal panel and the optical sheets. The method of claim 1, The compensation film is a liquid crystal display, characterized in that the in-cell coatable type (in-cell coatable type). The method of claim 9, The compensation film is a liquid crystal display device, characterized in that provided between the first substrate and the liquid crystal layer. The method of claim 9, The compensation film is a liquid crystal display device, characterized in that provided between the second substrate and the liquid crystal layer. The method of claim 1, The compensation film is a liquid crystal display device comprising a liquid crystal dispersed in a polymer. The method of claim 12, The compensation film is a liquid crystal display device, characterized in that the anisotropy is provided at the same time is cured by ultraviolet irradiation.

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