JPH095780A - Active matrix liquid crystal display - Google Patents

Abstract

(57) [Abstract] [Purpose] An active matrix liquid crystal in which the non-display liquid crystal cell area can be narrowed and the substrate can be effectively used without causing the unevenness of brightness on the image display and the deterioration of the liquid crystal sealing performance. An object is to provide a display device. [Configuration] 5 is a display liquid crystal cell region, which is a source signal line 1
3, gate signal wiring 14 and source electrode 1 connected to it
5, the gate electrode 16, the semiconductor layer 17 of the TFT, the drain electrode 18 and the pixel electrode 19 connected thereto.
Reference numeral 8 denotes a non-display liquid crystal cell area, in which a non-display dummy pixel 20 is formed. Like the display effective pixel 12, the non-display dummy pixel 20 is connected with the source signal line 13 and the gate signal line 26, and has a dummy source electrode 21, a dummy gate electrode 22, a dummy semiconductor layer 23, and a dummy drain electrode 2.
4, the dummy pixel electrode 25 is provided, and the size in the direction parallel to the source signal line 13 is formed to be half that of the display effective pixel 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called active matrix type liquid crystal display device which drives a liquid crystal by using a non-linear element.

[0002]

2. Description of the Related Art In recent years, due to advances in fine processing technology, material technology, high-density mounting technology, etc., liquid crystal displays have a wide range of screen sizes from 1 type to 17 type or more, and various applications such as AV, OA, and vehicle. The percentage of equipment is expanding rapidly, and it is attracting attention of the entire electronics industry as a key device that replaces the conventional CRT. Under such circumstances, the thin and lightweight peculiar to liquid crystal display devices have been further evolved, and C
Product areas that were difficult to achieve with RT (eg A4, B5
Size laptop to sub-notebook, DT
We are showing further development in N standard compliant car navigation systems, monitor-integrated video movies, pen input type portable information terminals, etc.). On the other hand, in order to reduce the material cost and improve the productivity, there is an active movement to increase the size and standardize the mother glass substrate. How to efficiently chamfer a large number of panels from a large mother glass substrate of the same size, or How to achieve a small panel with the same screen size, how to achieve a large screen size with the same panel size, and at the same time improve productivity without sacrificing performance, quality, and yield are important issues. It's starting.

First, an outline of a thin film transistor substrate of an active matrix type liquid crystal display device will be described.
FIG. 3 shows a schematic diagram thereof. Reference numeral 1 is a mother glass substrate, 2 is an effective region of a thin film transistor substrate required for a liquid crystal display device, and here, a case of a plurality of chamfers in which effective regions for two panels are arranged is shown. Reference numerals 3a and 3b are unit effective areas (hereinafter referred to as chips) for one panel. Reference numeral 4 denotes an area (hereinafter, referred to as a mother glass frame) necessary for transporting the mother glass substrate 1 in a manufacturing process, forming a recognition pattern, and the like. Effective area 2 of thin film transistor substrate
Inside, the display liquid crystal cell region 5 in which thin film transistors, which are active elements for switching the liquid crystal, are arranged in a matrix, and the drive driver mounting region 6 and the opposite substrate are attached to the liquid crystal material to be sealed and fixed in the display liquid crystal cell region 5. There are a seal region 7 for displaying, a display liquid crystal cell region 5 and a non-display liquid crystal cell region 8 sandwiched between the seal regions 7. The non-display liquid crystal cell region 8 is a marginal region that exists to prevent the display region from overlapping with the display liquid crystal cell region 5 even if the position of the seal region 7 is displaced due to manufacturing variations. is there. Also, here 9 is the seal area 7.
And a non-display liquid crystal cell region 8 are combined (hereinafter referred to as a screen frame), 10 is a region where the display liquid crystal cell region 5 and the non-display liquid crystal cell region 8 are combined (hereinafter referred to as a liquid crystal cell region)
It is.

In order to make the most effective use of the mother glass substrate 1, firstly, there is a method of minimizing the mother glass frame 4, but this is currently constant because of the restriction of the structure of the manufacturing equipment. The following sizes cannot be expected. Further, since the mother glass frame 4 has a constant value regardless of the number of chamfers of the chips 3a and 3b, the influence per chip is dispersed as the number of chamfers increases, so the influence on the chip size is not so large.

Secondly, when the effective area 2 of the thin film transistor substrate is considered to be constant, the maximum chip size for each chamfering number is determined by itself. Therefore, in order to enlarge the display liquid crystal cell area 5, the screen frame 9 is made small. There is no way but to do it. Further, even when the size of the display liquid crystal cell region 5 is fixed and the number of multi-panels is maximized, it is effective to minimize the size of the chips 3a and 3b by reducing the screen frame 9. . Further, since the screen frame 9 is almost constant without being restricted by the size of the display liquid crystal cell region 5,
The greater the number of chamfers, the greater the effect.

For this reason, a design measure is usually taken to minimize the screen frame 9. FIG. 4 is an enlarged view of the details near the frame of the screen. Reference numeral 30 is a display effective pixel in the display liquid crystal cell area 5, 31 is a non-display pixel in the non-display liquid crystal cell area 8, 32 is a source signal wiring, and 33 is a gate signal wiring. Here, like the display effective pixel 30, the non-display pixel 31 is connected with the source signal wiring 32 and the gate signal wiring 33, is driven in exactly the same manner as the display effective pixel 30, and is normally the same as the display effective pixel 30. In many cases, the pixel pattern of is arranged in one or more rows. There are several reasons for arranging the non-display pixel 31 in this way, but the biggest reason is that the reliability of display quality is a problem.

The problems of reliability of display quality are as follows. Usually, the alignment treatment for aligning the liquid crystal molecules in a predetermined direction is performed by rubbing a cloth using fibers such as rayon and nylon in a predetermined direction with the alignment film (polyimide resin) on the substrate under a constant load. Although the rubbing method is used, the alignment film, which was scraped off from the substrate by friction and adhered to the cloth, is reattached to the substrate as foreign matter in no small amount, and the amount of the adhered amount obviously changes greatly in the step shape of the substrate. Tend to be moderate. That is, they are reattached in a concentrated manner at the boundary between the area where the pixels are arranged and the wiring area. The reattached alignment foreign matter is in a state where the imide bond is destroyed by the frictional heat during rubbing and the water content in the air, and the carboxylic acid is easily separated as an ion. These diffuse as ionic impurities into the liquid crystal over time. The ionic impurities deteriorate the voltage holding ratio of the liquid crystal, but in a state where the liquid crystal is uniformly diffused in the liquid crystal, the uneven brightness on the image display is not recognized and it is not a big problem. However, as described above, the distribution of the redeposited foreign matter is concentrated around the screen from the beginning, and uniform diffusion is impossible. Further, since these impurities have ionicity, they have the property of moving in the liquid crystal cell as the driving time elapses, and in particular, are greatly affected by the gate signal having many DC components. That is, the ionic impurities move in a certain direction depending on the scanning direction of the gate, forming a region where they are concentrated. The ionic impurities concentrated in this region cause a local decrease in the charge retention rate, which is observed as brightness unevenness on the image display.

Therefore, in order to prevent the uneven brightness, which is a problem in the reliability of the display quality, the non-display pixel 31 which is normally driven is arranged in the non-display liquid crystal cell region 8 to generate the ionic impurities. The re-adhesion region of the rubbing foreign substance as the source is kept away from the display liquid crystal cell region 5, and the region where the ionic impurities moved by the scanning of the gate is finally concentrated is the gate of the non-display pixel 31 of the non-display liquid crystal cell region 8. It was an effective means to keep it near the electrodes.

[0009]

However, in the above-mentioned conventional structure, when an attempt is made to minimize the screen frame size in order to reduce the chip area under the same screen size and increase the number of multiple cuts, the seal area 7 is However, because of a problem in reliability, the width cannot be less than a certain width, so that the non-display liquid crystal cell region 8 is truncated and reduced only. In order to reduce the size of the non-display liquid crystal cell region 8, in the conventional technique, the only method is to reduce or eliminate the number of columns in which the non-display pixels 31 are arranged. This is because, if the non-display liquid crystal cell area 8 is reduced without changing the number of columns in which the non-display pixels 31 are arranged, considering the manufacturing variation of the seal area 7, the worst case is when the seal area 7 is not the display pixel. It overlaps with 31. Since the liquid crystal itself cannot exist in this overlapped portion, the function as a capture electrode for the ionic impurities possessed by the non-display pixel 31 described in the related art is lost, and the occurrence of uneven brightness on the image display is prevented. In addition, the contact surface of the seal area 7 with the active substrate side is normally a uniform and uniform source signal wiring or gate signal wiring. Therefore, there is a risk that it may cause a problem of sealing property due to deterioration of adhesion and a problem of unevenness of gap of liquid crystal cell due to unevenness of steps.

In order to solve the above-mentioned conventional problems, the present invention provides an active matrix type liquid crystal display device in which the substrate can be effectively used without causing the unevenness of brightness on the image display and the deterioration of the sealing performance of the liquid crystal. With the goal.

[0011]

According to another aspect of the present invention, there is provided an active matrix type liquid crystal display device in which scanning signal lines and display signal lines are arranged in an XY matrix on a main surface, and the scanning signal lines and the display signal lines are partitioned. A first substrate having a thin film transistor and a pixel electrode formed in a region, a second substrate overlaid on a main surface of the first substrate and having a counter electrode on a surface facing the main surface, and a first substrate And a liquid crystal enclosed between the second substrate, the pixel electrodes arranged on the outermost periphery of the first substrate are smaller than the shapes of the other pixel electrodes, and the scanning signal lines and the display signal lines on the outermost periphery are provided inside. It is characterized in that it is made into a non-display dummy pixel by being brought close to the above.

According to another aspect of the active matrix type liquid crystal display device, scanning signal lines and display signal lines are arranged in an XY matrix on the main surface, and thin film transistors and pixels are arranged in a region partitioned by the scanning signal lines and the display signal lines. A first substrate on which electrodes are formed, a second substrate on which a counter electrode is formed on a main surface of the first substrate and which faces the main surface, and a first substrate and a second substrate. A liquid crystal enclosed between the first substrate and one or more columns of pixel electrodes arranged on the outer periphery of the first substrate are omitted, and the scanning signal lines and the display signal lines corresponding to the omitted pixel electrode columns are moved inward. As a result, the dummy signal wiring is used.

[0013]

According to the structure of claim 1, the pixel electrodes arranged on the outermost periphery of the first substrate are made smaller than the shapes of the other pixel electrodes, and the scanning signal lines and the display signal lines on the outermost periphery are brought inward. Since this is a non-display dummy pixel, even if the non-display liquid crystal cell area is narrow, a non-display dummy pixel that has the same function as a normal non-display pixel can be arranged, and ionic impurities in the liquid crystal can be removed from the non-display liquid crystal cell. The area of the non-display liquid crystal cell can be narrowed and the substrate can be effectively used without causing unevenness in brightness on image display and deterioration of liquid crystal sealing performance.

According to the structure of claim 2, one or more pixel electrodes arranged on the outer periphery of the first substrate are omitted, and the scanning signal line and the display signal line corresponding to the omitted pixel electrode column are omitted. By arranging the dummy signal wiring by arranging the dummy signal wiring toward the inside, even if the non-display liquid crystal cell area is narrow, it is possible to keep the ionic impurities in the liquid crystal within the non-display liquid crystal cell area. The non-display liquid crystal cell region can be narrowed and the substrate can be effectively used without causing unevenness in brightness on the image display and deterioration of the liquid crystal sealing performance.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of the vicinity of a screen frame of a thin film transistor substrate of an active matrix type liquid crystal display device according to an embodiment of the present invention. The schematic structure of the thin film transistor substrate is similar to that of the example shown in FIG. 3, and the same portions are denoted by the same reference numerals.

In FIG. 1, 5 is a display liquid crystal cell region, and 7
Is a seal area, and 8 is a non-display liquid crystal cell area. The display liquid crystal cell region 5 includes a display effective pixel 12, a source signal line 13 serving as a display signal line, a gate signal line 14 serving as a scanning signal line and a source electrode 15 adjacent to the gate signal line 14, a gate electrode 16, a semiconductor layer 17 of a TFT, and a drain. It is composed of an electrode 18 and a pixel electrode 19 connected thereto.

In the non-display liquid crystal cell area 8, one non-display dummy pixel 20 is arranged in parallel with the gate signal line 14. . Like the display effective pixel 12, the non-display dummy pixel 20 is connected to the source signal line 13 and the gate signal line 26, and is connected to the dummy source electrode 21 and the dummy gate electrode 2.
2, the dummy semiconductor layer 23, the dummy drain electrode 24, and the dummy pixel electrode 25 are provided, but the size in the direction parallel to the source signal line 13 is set to the display effective pixel 12 in order to reduce the size.
Half of that of the gate signal wiring 26
Is also placed inside. At this time, since the potential of the dummy pixel electrode 25 is basically the same as the potential of the pixel electrode 19 of the display effective pixel 12, the size of the TFT and the parasitic capacitance, the dummy source electrode 21, the dummy gate electrode 22, the dummy It is desirable to optimize and adjust the design parameters of the semiconductor layer 23, the dummy drain electrode 24, and the dummy pixel electrode 25.

According to the active matrix type liquid crystal display device having such a configuration, even when the non-display liquid crystal cell region 8 is narrow and the non-display pixel having the same size as the display effective pixel 12 cannot be arranged, Since the non-display dummy pixels 20 that perform the same operation can be arranged in a half of the conventional area, the non-display dummy pixels 20 can be formed without reducing the distance from the seal area 7. Therefore, due to the function of the non-display dummy pixel 20 as a capture electrode for the ionic impurities, even if the ionic impurities are present in the liquid crystal, they can be retained in the non-display liquid crystal cell region 8.
The non-display liquid crystal cell region 8 can be narrowed and the substrate can be effectively used without causing unevenness in brightness on the image display and deterioration of the liquid crystal sealing performance.

In this embodiment, the case where the size of the non-display dummy pixel 20 is half the size of the display effective pixel 12 is arranged in one row has been described. However, it is smaller than the display effective pixel 12. For example, the size is not particularly limited, and the number of arranged rows is also not particularly limited. Another embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a schematic view of the vicinity of a screen frame of a thin film transistor substrate of an active matrix type liquid crystal display device according to another embodiment of the present invention. The same parts as those in the embodiment of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, only the dummy gate signal wirings 27 are arranged in the non-display liquid crystal cell area 8. Two dummy gate signal wirings 27 are arranged and the arrangement interval is the source signal wiring of the display effective pixel 12. 13 is 1/4 of the size of the side in the parallel direction. In this case, the thin film transistor and the pixel electrode are not arranged. According to the active matrix type liquid crystal display device configured as described above, the dummy gate signal wiring 27 capable of capturing the ionic impurities in the liquid crystal cell can be secured in the narrow non-display liquid crystal cell region 8. The same effect as that of the embodiment can be obtained.

In this embodiment, the case where two dummy gate signal wirings 27 having a pitch of 1/4 of the effective display pixels 12 are arranged is explained, but the non-display liquid crystal cell area 8 is used. The pitch and the number of arrangements may be freely selected as needed as long as the width can be narrowed. In each of the above-described embodiments, only one side of the non-display liquid crystal cell region 8 is described, but the configuration of the present invention may be similarly applied to the remaining three sides. For example, in the non-display liquid crystal cell region 8 in the direction of the gate signal wiring 14, a non-display dummy pixel having a size of 1/2 in the parallel direction is formed in the gate signal wiring 14, and the source signal wiring on the outermost periphery is inward. Alternatively, the dummy source signal wiring may be formed by bringing the source signal wiring inward by omitting the pixel electrode. Further, the non-display dummy pixel and the dummy signal wiring are not limited to be formed on only one side of the non-display liquid crystal cell region 8, but may be formed on two or more sides.

[0022]

According to the structure of the first aspect, the pixel electrodes arranged on the outermost periphery of the first substrate are made smaller than the shapes of the other pixel electrodes, and the scanning signal lines and the display signal lines on the outermost periphery are formed inside. The non-display dummy pixels can be arranged even if the non-display liquid crystal cell area is narrow by arranging the non-display dummy pixels so that the ionic impurities in the liquid crystal are not displayed. The size of the non-display liquid crystal cell can be narrowed and the substrate can be effectively used without causing unevenness in brightness on the image display and deterioration of the liquid crystal sealing performance. Large screen, high productivity, high quality, and high yield can be achieved at the same time.

According to the configuration of claim 2, one or more pixel electrodes arranged on the outer periphery of the first substrate are omitted, and the scanning signal lines and the display signal lines corresponding to the omitted pixel electrode columns are omitted. By arranging the dummy signal wiring by arranging the dummy signal wiring toward the inside, even if the non-display liquid crystal cell area is narrow, it is possible to keep the ionic impurities in the liquid crystal within the non-display liquid crystal cell area. The non-display liquid crystal cell area can be narrowed and the substrate can be effectively used without causing uneven brightness on the image display and deterioration of the liquid crystal sealing performance. Compact, large screen, high productivity,
The effect is that high quality and high yield can be achieved at the same time.

[Brief description of drawings]

FIG. 1 is a schematic view of the vicinity of a screen frame of an active matrix type liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a schematic view of the vicinity of a screen frame of an active matrix type liquid crystal display device according to another embodiment of the present invention.

FIG. 3 is a schematic view of a thin film transistor substrate of an active matrix type liquid crystal display device.

FIG. 4 is a schematic view of the vicinity of a screen frame of an active matrix type liquid crystal display device of a conventional example.

[Explanation of symbols]

 5 Display Liquid Crystal Cell Area 7 Seal Area 8 Non-Display Liquid Crystal Cell Area 12 Display Effective Pixel 13 Source Signal Wiring 14, 26 Gate Signal Wiring 19 Pixel Electrode 20 Non-Display Dummy Pixel 27 Dummy Gate Signal Wiring

Claims (2)

[Claims] 1. A first substrate in which scanning signal lines and display signal lines are arranged in an XY matrix on a main surface, and thin film transistors and pixel electrodes are formed in regions partitioned by the scanning signal lines and display signal lines. A second substrate overlaid on a main surface of the first substrate and having a counter electrode formed on a surface facing the main surface; and a liquid crystal sealed between the first substrate and the second substrate. An active matrix type liquid crystal display device provided with the pixel electrodes arranged on the outermost periphery of the first substrate smaller than the shapes of other pixel electrodes, and the scanning signal lines and display signal lines on the outermost periphery are brought inward. Accordingly, the active matrix type liquid crystal display device is characterized by using non-display dummy pixels. 2. A first substrate in which scanning signal lines and display signal lines are arranged in an XY matrix on the main surface, and thin film transistors and pixel electrodes are formed in regions partitioned by the scanning signal lines and display signal lines. A second substrate overlaid on a main surface of the first substrate and having a counter electrode formed on a surface facing the main surface; and a liquid crystal sealed between the first substrate and the second substrate. An active matrix type liquid crystal display device comprising: a first substrate, wherein one or more columns of pixel electrodes arranged on the outer periphery of the first substrate are omitted, and scanning signal lines and display signal lines corresponding to the omitted pixel electrode columns An active matrix type liquid crystal display device, characterized in that a dummy signal wiring is formed by moving the inside.