JP3005342U - Liquid crystal display element - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent a display defect from occurring in the outer portion of the liquid crystal display element, which has a larger resistance than the center of the lead pattern connected to one driver chip. A liquid crystal comprising a pair of base panels each having a common electrode and a segment electrode, a liquid crystal interposed between the pair of base panels, and a frit seal for sealing the liquid crystal between an upper panel and a lower panel. In the display element, the common and segment electrodes are connected to lead patterns formed so that the resistances of the central portion and the outer portion are constant.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a liquid crystal display device. More specifically, since the display capacitance of the liquid crystal display device is increased, the number of X and Y electrodes driven by one driver chip is increased. The present invention relates to a liquid crystal display element capable of preventing display defects from occurring when the X and Y electrodes are driven due to different resistances of respective lead patterns.

[0002]

[Prior art]

 In general, a liquid crystal display element can perform a predetermined display by rotating the external light by utilizing the twist or scattering of the liquid crystal by an external impact, especially an electric field. (Smetic), nematic (Nematic), cholesteric liquid crystal and the like are used, and the nematic liquid crystal is most often used for information.

[0006] Here, the liquid crystal display device includes types such as twisted nematic (TN), super twisted nematic (STN), and double super twisted nematic (DSTN) according to the twist angle of the liquid crystal according to the rubbing angle of the alignment film. There is.

As shown in FIG. 2, the liquid crystal display device includes X and Y electrodes 51 and 50 formed in a matrix shape, upper and lower base panels 52 and 53, and the upper and lower base panels. A seal 54 (for example, by a glass frit) that not only keeps the panels 52 and 53 fixed but also fixes them, an alignment film 55 to which the X and Y electrodes 51 and 50 are applied, and the upper and lower base panels 52. , 53, and upper and lower polarizing plates 56, 57, respectively.

Further, a lead pattern 58 is formed on the X electrode 51 to extend to the outside of the frit seal 54, and a film 60 to which a driver chip (driving circuit) 59 is attached is attached to the lead pattern 58. Has been.

Of course, although not shown in FIG. 2, the driver chip as described above is also connected through a film to another X electrode which is orthogonal to and insulated from the X electrode 51. Has a pattern (not shown) having the same pitch as the lead pattern 58 formed on the X and Y electrodes 51 and 50.

That is, when a signal is applied to the X, Y electrodes 51, 50 through the driver chip 59, an electric field is formed in a predetermined pixel and the liquid crystal in that portion is twisted, so that a backlight not shown is shown. Twist the light and let it pass, for example.

Here, since the directions of the light passing through the upper and lower polarizing plates 56 and 57 are orthogonal to each other, the light twisted by the liquid crystal passes through the upper polarizing plate 56 and the untwisted light is By preventing the light from passing through the upper polarizing plate 56, predetermined display can be performed only for the selected pixel.

Many methods have been developed for connecting the driver chip 59 to the X and Y electrodes 51 and 50 of the liquid crystal display device as described above, which are generally COB (Chip On Board) and TAB (Tape Automated). Bonding), COG (Chip On Glass), and the like. Among them, the TAB method includes not only the driver chip 59 mounted on the film 60 as shown in FIG. The pattern 61 is formed at the same pitch as that of the pattern (not shown).

In particular, the method of connecting the driver chip 59 of the TAB method is the same as the method of connecting the X and Y electrodes 51 and 50 formed on the upper and lower base panels 52 and 53.

Of course, as shown in FIG. 4, the pattern 61 is formed to gather on the pad 62 to which the film is connected in a state of being extended from the Y electrode 50 or the X electrode 51, that is, the driver chip (see FIG. (Not shown) is connected to a lead pattern 58 formed so as to spread radially.

[0012]

[Problems to be solved by the device]

 However, in the liquid crystal display device as described above, under the present circumstances where the X, Y electrodes 51, 50 are gradually becoming denser and finer, the X, Y electrodes 51, 50 which must be driven by one driver chip 59. The number increases. Therefore, a group of lead patterns 58 formed radially around the trivert chip 59 has a length of the outer portion that is longer than the center. Therefore, when applying a signal, the resistance of the outer portion from the center of the lead pattern 58 is inevitable. Grows to.

As described above, when the resistance of the outer portion of the lead pattern 58 is higher than that of the center of the lead pattern 58, the potential of the signal transmitted through the outer portion of the lead pattern 58 decreases, so that the pixels driven through the outer portion of the lead pattern 58 are driven at a potential lower than the proper potential. Will be done.

As a result, the twist angle of the liquid crystal driven at a lower potential than appropriate becomes smaller, and the amount of light transmitted by the back light becomes smaller than the pixels driven by the central portion of the group of lead patterns 58. Pixels driven by the outer portion of the group of lead patterns 58 appear darker than other pixels, resulting in display defects (unevenness).

Therefore, in the liquid crystal display device, an object of the present invention is to display a liquid crystal display device on a portion of the lead pattern connected to one driver chip because the resistance of the outer portion of the lead pattern is larger than that of the central portion of the lead pattern. Another object of the present invention is to provide a liquid crystal display device that can prevent defects from occurring.

[0016]

[Means for Solving the Problems]

 To achieve the above object, the present invention provides a liquid crystal display device having a pair of base panels having X and Y electrodes and a liquid crystal interposed between the pair of base panels, wherein at least the X and Y electrodes are provided. A lead pattern formed so that the resistance of the central portion and the outer portion of the group of lead patterns is constant is connected to one side (claim 1).

With this configuration, the resistance of each of the lead patterns radially formed around one driver chip is uniformly formed, thereby improving the display failure of the liquid crystal display device.

As a specific mode, for example, the lead pattern resistance is uniformly adjusted by forming the length and width of each lead pattern to be constant. In order to cope with this, the connection end of the lead pattern of the group of X or Y electrodes with the lead pattern should be gradually and gradually approached toward the other end of the lead pattern as the group approaches from the central part to the outer part. (Claim 2) It is most effective to connect the predetermined lead pattern to both the X electrode and the Y electrode (claims 10 and 11), but at least this lead pattern is provided for the X electrode having a great influence.

In the STN, the X and Y electrodes correspond to scan lines and data lines.

[0020]

[Action]

 By equalizing the resistances of the lead patterns connected to one driver chip, signals transmitted through the driver patterns have the same potential, and the twist angle of the liquid crystal twisted due to the potential difference becomes constant. This makes the transmitted light of each excitation pixel (group of pixels) uniform.

That is, the unevenness (display unevenness) on the screen displayed by the liquid crystal is removed, and the display defect is prevented.

[0022]

[Preferred Embodiment]

 Preferred embodiments will be shown below. The arrangement of the connection ends of the group of X and / or Y electrodes with the lead pattern has a stepwise step, and this step has a connection with the position of the connection end when the lead patterns are arranged with a constant length. It is preferable that the step is configured as a step that is allowed. (Claim 3) If it does in this way, an object will be achieved with an extremely simple composition.

It is preferable that the central portion and the outer portion of the group of lead patterns have the same width (claim 5). This also contributes to simplification of the structure.

A structure having a seal member (for example, a glass seal) for sealing the liquid crystal between a pair of base panels is preferable (claim 6). However, the sealing material is not particularly limited.

The group of lead patterns can be connected to one driver chip (claim 7). This configuration serves the most purpose.

Further, it is preferable from the viewpoint of symmetry and manufacturability that the group of lead patterns is formed so as to have an array extending substantially radially from the central portion to the outer portion (claim 8).

The group of lead patterns has a linear pattern in the center, and a linear portion parallel to the linear pattern in the central portion as it goes to the outer portion, and a radial portion which becomes continuous with this and becomes longer as it goes to the outer portion. It can consist mainly of parts. This makes it possible to easily connect electrodes having the same lead pattern length and arranged at predetermined intervals.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0029]

【Example】

 FIG. 1 is a partially enlarged view showing a lead pattern of a liquid crystal display device according to the present invention, in which a connecting end of an X, Y electrode 1 with a lead pattern 2 is formed to be gradually higher as it approaches the outer contours of the left and right, A lead pattern 2 is connected to the X and Y electrodes 1. The present invention can also be applied to a data line and a scan line having a driving circuit in a TFT type LCD.

Here, as described above, the group of X and Y electrodes 1 gradually and stepwisely adapts to the radial arrangement shape of the lead pattern 2 as the connection end of the group of X and Y electrodes 1 with the lead pattern 2 approaches the outer portion. The length of the lead pattern 2 is long, that is, the distance from the other end of the lead pattern is gradually reduced in the long axis direction of the electrode 1. Be the same.

That is, the connection ends of the X and Y electrodes 1 have a difference in length by d ₁ , d ₂ , and d ₃ , and this difference in length goes from the central portion of the group of lead patterns 2 to the outer portion. This is made to correspond to the difference in the position of the end portion of the lead pattern generated as a result in the long axis direction of the electrode 1.

For example, the difference in length between the central portion and the outer portion of the lead pattern 2 is 0.021 μm for each lead pattern 2, and the width of the X and Y electrodes 1 is 0.275 μm. When the width of 2 is 0.06 μm, the increase of the resistance according to the increase of the length of the lead pattern 2 as in the prior art appears as the following formula (1), and the X and Y electrodes increase according to the present invention. The resistance increase of 1 appears according to the following equation (2). 0.021 / 0.06 * 12.5 = 4.375Ω ··· (1) 0.021 / 0.275 * 12.5 = 0.95Ω ··· (2) However, the lead pattern and both X and Y electrodes are made of the same material and have the same thickness, and 12.5 indicates the unit length and the resistance Ω per unit width (m).

That is, assuming that the lengths of the lead patterns 2 are the same, the lengths of the X and Y electrodes 1 are slightly increased, but the increase in the resistance as a whole in the outer portion is reduced to make the display failure remarkable. Can be reduced to

Of course, when the lead pattern 2 is formed to have the same width and the same coating density, and when the lead patterns 2 have the same length as described above, the lead patterns 2 have the same resistance. Then, a film 60 having a driver chip (not shown) is attached to the pad 3 of the lead pattern 2, and the output terminal of the driver chip (driving circuit) is connected.

Note that the X and Y electrodes used in the present application are similarly applied to the data line having the drive circuit and the scan line having the drive circuit. In the TFT type LCD, the COM electrode (or the counter electrode) is not used. Generally, it can be arranged parallel to the scan line. In FIG. 2, the X (segment) electrode is illustrated as 51 for only one of the data line and the scan line for simplification, but the other electrode is orthogonal to and insulated from the illustrated 51 and is the same substrate (base panel) in a matrix form. Is installed in.

In FIG. 3, an X electrode, a Y electrode orthogonal to the X electrode, and a COM electrode arranged on the opposite side of the X electrode are shown as a representative of a radial lead pattern. The COM electrode is connected to a common pad (terminal).

[0037]

[Effect of device]

 As described above, according to the present invention, it is possible to provide a more uniform and clear liquid crystal display device in which the uniformity of image quality is improved as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a partially enlarged view showing a lead pattern according to the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a general liquid crystal display element.

FIG. 3 is a schematic plan view showing a state in which a driver chip is attached to a liquid crystal display element by a TAB method.

FIG. 4 is a partial enlarged view showing a lead pattern used in a conventional liquid crystal display element.

[Explanation of symbols]

 1 X, Y electrode 2 Lead pattern 3 Pad 60 Film

Claims (11)

[Scope of utility model registration request] 1. A pair of base panels having X and Y electrodes,
In a liquid crystal display device having a liquid crystal interposed between the pair of base panels, a lead formed on at least one of the X and Y electrodes so that a central portion and an outer portion of a group of lead patterns have a constant resistance. A liquid crystal display device characterized by connecting patterns. 2. The lead patterns are formed such that the center portion and the outer portion of the group of lead patterns have the same length and width so that the resistance values are the same, and X and / or X connected thereto. The liquid crystal display device according to claim 1, wherein the connection end of the Y electrode is configured to have a length that gradually changes toward the other end of the lead pattern with a step difference as it approaches the outer portion. 3. The arrangement of connection ends of the group of X and / or Y electrodes with the lead pattern has a stepwise step, and the step has the connection end when the lead patterns are arranged with a constant length. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is configured as a level difference corresponding to an allowance for connection with the position. 4. The arrangement of connecting ends of the group of X and Y electrodes with the lead pattern has a stepwise step, and the stepwise step has the following steps:
The liquid crystal display device according to claim 2, wherein the liquid crystal display device is configured as a stepped portion that allows connection with the position of the connection end of the lead pattern. 5. The liquid crystal display device according to claim 2, wherein the central portion and the outer portion of the group of lead patterns have the same width. 6. The liquid crystal display device according to claim 1, further comprising a seal member for sealing the liquid crystal between the pair of base panels. 7. The lead patterns of one group are connected to one driver chip.
1. A liquid crystal display device according to any one of 1. 8. The liquid crystal display element according to claim 1, wherein the group of lead patterns is formed in an array extending substantially radially from a central portion to an outer portion. 9. The lead pattern of the group has a linear pattern in the central portion, and a linear portion parallel to the linear pattern in the central portion is connected to the outer portion and becomes longer as it goes to the outer portion. 9. The liquid crystal display device according to claim 8, which is mainly composed of radial portions. 10. A liquid crystal display device comprising a pair of base panels on which X and Y electrodes are respectively formed, and a liquid crystal interposed between the pair of base panels.
A liquid crystal display element, wherein a lead pattern formed so that the resistance of the central portion and the outer portion of a group of lead patterns is constant is connected to the electrode. 11. The lead patterns are formed such that the central portion and the outer portion of a group of lead patterns have the same length and width so that the resistance values are the same, and the X and Y electrodes connected thereto. 11. The liquid crystal display device according to claim 10, wherein the connecting end of the lead pattern has a length that gradually changes toward the other end of the lead pattern toward the other end with a step.