JPH09101540A - Active matrix type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent light leakage around a display area without increasing the number of processes. SOLUTION: Picture element electrodes 12 arranged as a matrix on a first transparent substrate, switching elements which send a video signal to these picture element electrodes and consist of TFTs, gate lines 3 connected to gates of these switching elements, an array substrate 1 having signal lines 7 through which the video signal is sent to switching elements, a counter substrate which has a common electrode formed on a second transparent substrate, and a liquid crystal layer sealed between the array substrate 1 and the counter substrate are provided, and two first light shielding frames 4a and 4b which are formed approximately in parallel with gate lines 3 at the time of forming the gate lines 3 and two light shielding frames 10a and 10b which are formed in parallel with signal lines at the time of forming the signal lines are provided in the outer periphery of the display area of the array substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, an active matrix type display device using liquid crystal is becoming a display device replacing the CRT. FIG. 3 is a schematic sectional view of the structure of a general active matrix type liquid crystal display device. In this liquid crystal display device, a light shielding layer 16 having an opening made of a chromium film having a thickness of 0.1 μm, for example, is formed on a transparent substrate 15, and the light shielding layer 16 has, for example, a pigment dispersion method or an electrodeposition method. Alternatively, a colored layer 17 formed by a printing method or the like is provided. Then, the ITO (Indi
a common electrode 18 made of um tin oxide), and an alignment film 19 made of, for example, polyimide is further provided on the common electrode 18. Further, on one transparent substrate 21, one TFT (Thin Film Transistor) facing the light shielding layer 16 is provided.
sistor) 22 and a pixel electrode 23 made of ITO is provided at a position corresponding to the opening of the light shielding layer 16. The TFT 22 and the pixel electrode 23 are electrically connected and are covered with an alignment film 25 made of polyimide.

A liquid crystal 32 is sealed between these two substrates, and a polarizing plate (not shown) is attached to the outside of each of these two substrates. The distance between the two substrates is kept constant by the spacer 31.

In such a liquid crystal display device, the TFT
A display operation can be performed by applying a video signal to the pixel electrode 23 by switching 22 to control the alignment of the liquid crystal 32 and modulating the light transmitted through the colored layer 17.

[0005]

In the above-mentioned conventional liquid crystal display device, light leakage from the periphery of the pixel electrode 23 and T
The light shielding layer 16 is formed in a region other than the pixel electrode 23 in order to prevent light from entering the FT 22. But,
A margin (for example, 8 μm) for misalignment between the substrate 15 and the substrate 21 and a pitch misalignment between the light shielding film 16 and the TFT 22.
Therefore, the light shielding layer 16 is designed to have a large width. Therefore, there is a problem that the opening of the light shielding layer 16 becomes small and the brightness as a display device is lowered.

In order to solve this problem, a structure in which a colored layer (color filter) is provided on or under the pixel electrode of the substrate on which the TFT is arranged and only the common electrode is formed on the substrate corresponding to the above substrate An improved liquid crystal display device has been proposed.

However, this improved liquid crystal display device has a problem that the number of steps for preventing light leakage from the periphery of the display area increases. Specifically, when the TFT is covered with a resin containing a black pigment, the periphery of the pixel region may be covered, but it is necessary to use a material having excellent electrical insulation and light shielding properties as the resin. However, in general, carbon is used as a pigment in a material having an excellent light-shielding property, which causes a problem in electrical insulation. On the other hand, in order to provide electric insulation, it is necessary to provide a transparent electric insulation layer before coating with a black resin, which causes a problem of increasing the number of steps.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an active matrix type liquid crystal display device capable of preventing light leakage around the display region without increasing the number of steps. To do.

[0009]

According to a first aspect of an active matrix type liquid crystal display device of the present invention, pixel electrodes arranged in a matrix on a first transparent substrate and a video signal are sent to the pixel electrodes. An array substrate having a switching element formed of a TFT, a gate line connected to the gate of the switching element, and a signal line for transmitting the video signal to the switching element, and a common substrate formed on the second transparent substrate A counter substrate having electrodes, a liquid crystal layer sealed in a gap between the array substrate and the counter substrate,
And two first light-shielding frames formed at the time of forming the gate line so as to be substantially parallel to the gate line, and formed at the time of forming the signal line so as to be parallel to the signal line. Two second light-shielding picture frames are provided on the outer periphery of the display area of the array substrate.

A second aspect of the active matrix type liquid crystal display device according to the present invention is the liquid crystal display device according to the first aspect, wherein the first and second light-shielding picture frames are coated with a colored layer made of an electrically insulating resin. It is characterized by

A third aspect of the active matrix type liquid crystal display device according to the present invention is the liquid crystal display device according to the first aspect, wherein a color filter is formed on the display area of the array substrate, The second light-shielding frame is coated with a colored layer made of an electrically insulating resin, which is formed when the color filter is formed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an active matrix type liquid crystal display device (hereinafter, also simply referred to as a liquid crystal display device) according to the present invention will be described with reference to FIGS. FIG. 1 is a plan view of an array substrate according to the liquid crystal display device of the present embodiment, and FIG. 2 is a configuration diagram showing a configuration of the array substrate. In the liquid crystal display device of this embodiment, liquid crystal is sealed between two substrates which are arranged facing each other, and the array substrate 1 which is one of the two substrates which are arranged facing each other is as follows. It is formed.

First, as shown in FIG. 2B, a metal such as molybdenum is deposited on the transparent substrate 2 by sputtering to a thickness of about 0.3 μm, and then the metal film is formed by photolithography. Pattern into a predetermined shape,
The gate line 3 is formed. At the time of this patterning, as shown in FIG. 1, on the two sides of the outer periphery of the display region, a part of the frame is formed on the outer periphery of the display region in parallel with the gate lines 3, for example, a width of 3 mm
The dummy gate lines 4a and 4b are patterned. One of the dummy gate lines 4a and 4b, for example, the dummy gate line 4a is also used as a gate line (see FIG. 1).

Next, a gate insulating film 5 made of, for example, silicon dioxide or silicon nitride and having a film thickness of 0.15 μm is formed on the transparent substrate 2 on which the gate lines 3 and the dummy gate lines 4a and 4b are formed (FIG. 2). (See (b)), the semiconductor layer 6 is provided on the gate insulating film 5. Then, a signal line 7 and a drain electrode 8 are formed by depositing, for example, a metal film made of aluminum with a film thickness of 0.3 μm on the transparent substrate 2 on which the semiconductor layer 6 is formed (FIG. 2B). reference). When the signal line 7 is formed, it becomes a part of the frame on the outer periphery of the display area in parallel with the signal line 7, for example, the width is 3 m.
m dummy signal lines 10a and 10b are patterned, and one of the dummy signal lines 10a and 10b, for example, the dummy signal line 10a is used as a signal line (see FIG. 1).
reference). The source electrode is formed from a part of the signal line 7. A gate electrode is formed of a part of the gate line 3, and the gate electrode, the gate insulating film 5, the semiconductor layer 6, the source electrode, and the drain electrode 8 form a TFT that serves as a switching element.

Further, a color filter 11 formed by patterning a negative resist containing a red, green or blue pigment is provided on the pixel region. Then, when the color filter 11 is formed, a negative resist dummy pattern containing red, green, and blue pigments is sequentially formed on the dummy gate lines 4a and 4b and the dummy signal lines 10a and 10b.

A pixel electrode 12 made of ITO having a film thickness of 0.1 μm is formed on the color filter 11, and the pixel electrode 12 is electrically connected to the drain electrode 8.

Then, the TFT element 9 and the pixel electrode 12
The array substrate 1 is completed by forming an alignment film (not shown) made of polyimide on the transparent substrate 2 on which is formed.

The counter substrate (not shown) arranged so as to face the array substrate 1 has a transparent substrate on which an ITO film having a film thickness of 0.15 μm, for example, is formed as a common electrode. An alignment film made of polyimide is formed on the film.

Then, liquid crystal is sealed in the gap between the array substrate 1 and the counter substrate, the periphery of these substrates is sealed, and then a polarizing plate is placed on the surface of both substrates opposite to the liquid crystal sealed surface. The liquid crystal display device is completed by providing the liquid crystal display device.

As described above, according to the liquid crystal display device of the present embodiment, the light-shielding frames 4a, 4b, 1 formed when the signal line 7 and the gate line 3 are formed on the outer periphery of the display area.
Since 0a and 10b are provided, light leakage around the display area can be prevented without increasing the number of steps. Further, since the dummy pattern of the color filter is formed on the frame 4a, 4b, 10a, 10b, reflection of external light can be prevented.

In the liquid crystal display device of this embodiment, the pixel electrode 12 is provided on the color filter 11, but it may be provided below the color filter 11. Further, the color filter may be provided on the counter substrate side.

Further, in the liquid crystal display device of the present embodiment, the dummy pattern of the color filter is provided on the dummy gate lines 4a and 4b and the dummy signal line, but this dummy pattern is made of an electrically insulating black resist (resin). You may form using it.

Further, the color filter (coloring layer) is formed by using a resist containing a pigment by a photolithography technique, but it may be formed by a dyeing method, a printing method, an electrodeposition method or the like.

In the liquid crystal display device of this embodiment, the dummy gate line 4a and the dummy signal line 10a are used as the gate line and the signal line, respectively, but the gate line 3 and the signal line 7 are separately formed without using them. You may.

[0025]

As described above, according to the present invention, light leakage around the display area can be prevented without increasing the number of steps.

[Brief description of the drawings]

FIG. 1 is a plan view of an array substrate according to an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a configuration diagram showing a configuration of an array substrate according to an embodiment of a liquid crystal display device of the present invention.

FIG. 3 is a cross-sectional view of a conventional liquid crystal display device.

[Explanation of symbols]

 1 array substrate 2 transparent substrate 3 gate line 4a dummy gate line 4b dummy gate line 5 gate insulating film 6 semiconductor layer 7 signal line 8 drain electrode 9 TFT element 10a dummy signal line 10b dummy signal line 11 color filter (coloring layer) 12 image electrode

Claims (3)

[Claims] 1. A pixel electrode arranged in a matrix on a first transparent substrate, and a TF for sending a video signal to the pixel electrode.
An array substrate having a switching element made of T, a gate line connected to the gate of the switching element, and a signal line for sending the video signal to the switching element, and a common substrate formed on the second transparent substrate. A counter substrate having an electrode; and a liquid crystal layer sealed in a gap between the array substrate and the counter substrate. Two counter electrodes formed at the time of forming the gate line so as to be substantially parallel to the gate line. 2 formed at the time of forming the signal line so as to be parallel to the first light-shielding frame and the signal line 2
An active matrix liquid crystal display device, wherein a second light-shielding frame of a book is provided on the outer periphery of the display area of the array substrate. 2. The active matrix type liquid crystal display device according to claim 1, wherein the first and second light-shielding picture frames are coated with a colored layer made of an electrically insulating resin. 3. A color filter is formed on a display area of the array substrate, and the first and second light-shielding picture frames are formed when the color filter is formed and are made of an electrically insulating resin colored layer. The active matrix type liquid crystal display device according to claim 1, wherein the active matrix type liquid crystal display device is coated with.