JP2538004B2 - Liquid crystal display - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-linear element, particularly a thin film transistor (hereinafter referred to as a thin film transistor).
The present invention relates to a liquid crystal display device that drives a liquid crystal to display an image using an active matrix substrate on which TFTs are formed.

2. Description of the Related Art Liquid crystal display devices are considered to be promising among thin displays because they have features such as low power consumption and easy full-color display. In recent years, liquid crystal display devices have been desired for various purposes,
Production of various panels such as a large screen, a small screen, low density pixels, and high density pixels is required.

FIG. 5 shows a conventional thin film transistor (hereinafter abbreviated as TFT).
An equivalent circuit diagram of a liquid crystal panel portion of a liquid crystal display device using an active matrix substrate is shown. Row wiring 2 (... X _i-1 , X _i , X _{i + 1} , ...) And column wiring 3 on the glass substrate 1.
At each position where (... Y _j-1 , Y _j , Y _{j + 1} ...) Crosses, the TFT 4 which is a non-linear element connects its gate electrode to the row wiring and the source electrode to the column wiring. Formed,
The transparent display electrode 5 for applying a voltage to the liquid crystal is formed so as to be connected to the drain electrode of the TFT 4. A liquid crystal display device is constituted by sandwiching liquid crystal between the active matrix substrate and a counter substrate on which red, green and blue color filters and transparent electrodes are formed. The red, green, and blue color filters respectively correspond to the transparent display electrodes 5 in a one-to-one manner, and constitute one minimum display unit pixel (a portion surrounded by a broken line in FIG. 5). Further, as shown in the figure, every other row wiring is shifted in the left-right direction by 1/2 of the pixel pitch to prevent a fixed pattern noise generated in a moire pattern.

The image display is performed by selectively driving the TFTs of the required pixels by the row wiring 2 and the column wiring 2 to supply an image signal to the transparent display electrode, and applying a voltage to the liquid crystal together with the transparent counter electrode.

Further, conventionally, active matrix substrates for low-density pixel liquid crystal panels and high-density pixel liquid crystal panels have been manufactured in separate steps.

Problems to be Solved by the Invention However, the following problems occur in the configuration described above. When the TFT does not operate normally due to a defect in the manufacturing process of the active matrix substrate, the corresponding pixel causes a display defect, and a so-called point defect defect occurs. Also, if there is a short circuit at the point where the row wiring and the column wiring intersect, it is corrected by cutting the short circuit with a laser, etc., but at this time the TFT located at that point will not work,
Similar to the above, the image becomes defective in point defects.

Further, by shifting one pixel in the left-right direction, the column wiring is substantially lengthened and a large number of bent portions are formed, so that a defect such as disconnection of the column wiring is likely to occur.

Further, since the active matrix substrates for the low-density pixel liquid crystal panel and the high-density pixel liquid crystal panel are manufactured in separate steps, the productivity is low, and therefore the production cost of the active matrix substrate is increased, resulting in the cost of the liquid crystal display device. There was a problem that the cost was high.

The present invention has been made in view of the above problems, and uses an active matrix substrate for a high-density pixel liquid crystal panel,
The liquid crystal panel is configured so that there are a plurality of transparent display electrodes corresponding to one pixel of the low-density pixel liquid crystal panel, and the whole pixel is devised so as not to have a point defect defect. It is intended to provide a liquid crystal display device capable of preventing the above defects and obtaining good images. Further, as described above, the present invention provides a low-cost liquid crystal display device by sharing the active matrix substrate for the low-density pixel liquid crystal panel and the high-density pixel liquid crystal panel to reduce the manufacturing cost of the active matrix substrate. Is.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention connects a plurality of column wirings and a plurality of row wirings, and connects so that signals are supplied from the wirings to respective positions where these wirings intersect. A non-linear element, a first substrate on which transparent display electrodes connected to these non-linear elements are formed, and a second substrate on which a transparent counter electrode is formed, respectively. A liquid crystal display device having a liquid crystal panel in which a main surface on which the transparent electrode is formed is opposed to an inner surface and liquid crystal is sandwiched in the opposed space. The non-linear element is connected to a column wiring or a row wiring so that a signal can be supplied to the transparent display electrodes positioned in the order of (a) above or below the row wiring of the first substrate. Signals are supplied to the transparent display electrodes located So that the non-linear element is connected to the row wiring so that a fixed number of row wirings are used as a repeating unit in a left-right alternating order with respect to the column wiring, and (b) left with respect to the column wiring of the first substrate. Alternatively, the non-linear element is connected to a column wiring so that a signal can be supplied to the transparent display electrode located on either one of the right and the row wirings in a vertically alternating order with a fixed number of column wirings as a repeating unit. The column wiring, the row wiring, or both wirings are repeatedly short-circuited every fixed number of times to supply the same signal, and a short-circuit wiring for simultaneously driving a fixed number of the non-linear elements is provided.

Operation With the above configuration, a plurality of transparent display electrodes of the active matrix substrate for a high density pixel liquid crystal panel constitutes one pixel of a low density pixel liquid crystal panel, and constant column wiring and row wiring are short-circuited to make the above plurality of The non-linear element is driven so that the same signal can be simultaneously supplied to the transparent display electrodes, and the liquid crystal is operated to display an image. Therefore, even if a signal is not supplied to the transparent display electrode due to a malfunction of the non-linear element and the liquid crystal in that part does not operate, the non-linear element such as one pixel operates in the present invention, and the signal is transmitted to the transparent display electrode. Is supplied to operate the liquid crystal, the pixel does not become a point defect.

Further, according to the present invention, a non-linear element is connected to a column wiring and a row wiring so that one pixel composed of a plurality of transparent display electrodes is sequentially shifted in a horizontal direction or a vertical direction by a certain number of transparent electrodes, thereby providing a moire display. Fixed pattern noise can be suppressed.

Further, since the low-density liquid crystal panel is formed using the high-density pixel liquid crystal panel active matrix substrate as described above, it is not necessary to prepare an active matrix substrate dedicated to the low-density pixel liquid crystal panel. That is, the manufacturing processes of the active matrix substrates for the high density pixel liquid crystal panel and the low density pixel liquid crystal panel can be unified. Further, since the above-mentioned short-circuit wiring is selectively formed, it can be divided into a high-density pixel liquid crystal panel and a low-density pixel liquid crystal panel depending on the degree of point defects due to defects of the non-linear element. With the above operation, the production cost of the liquid crystal display device can be comprehensively reduced.

Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an equivalent circuit diagram of an active matrix substrate of a liquid crystal panel portion of a liquid crystal display device which is an embodiment of the present invention. 480 row wirings 22 (X2 _{1 to} X2 ₄₈₀ ) on the glass substrate 21
And 701 column wirings 23 (Y2 _{0 to} Y2 ₄₈₀ ) are formed at respective positions where the TFTs 24 connect the gate electrodes to the row wirings and the source electrodes to the column wirings, and apply a voltage to the liquid crystal. The transparent display electrode 25 is formed so as to be connected to the drain electrode of the TFT 24. At this time, as shown in the figure, the gate electrode of each TFT 24 is connected to the transparent display electrode 25 located under the row wiring so as to supply a signal. Then, for every two row wirings, that is, X2 _2n-1 , X2 _2n , (n = 1,
(3, 5, ..., 239) row electrodes are connected to the source electrodes of the TFTs so that signals can be supplied to the transparent display electrodes 25 located on the left side of the column wires, and then the next Two row wirings X2 _{2n + 1} , X2 _{2 (n + 1)} , (n = 1, 3, 5,
, 239), the source electrode of the TFT having the gate electrode connected thereto is connected to the transparent display electrode located on the right side of the column wiring so that a signal can be supplied. In this way the left side,
The source electrodes are alternately connected on the right side. Further, the row wirings X2 _2n-1 and X2 _2n (n = 1, 2, ...)
The column wirings Y2 _2n-1 and Y2 _2n (n = 1, 2, ...) Are short-circuited by a short-circuit line 26 such as chromium that can be removed by etching.

In the liquid crystal display device of the present embodiment, red, green and blue color filters are formed using the above-mentioned active matrix substrate so that the four transparent display electrodes 25 surrounded by broken lines in FIG. 1 form one pixel. And a counter substrate. That is, a liquid crystal display device of a low density pixel liquid crystal panel of 350 × 240 pixels is realized.

In the liquid crystal display device having such a configuration, short-circuited row wirings X2 _2n-1 and X2 _2n (n = 1, 2, ...) And column wiring Y2
_4n TFTs are driven simultaneously by _2n-1 and Y2 _2n (n = 1, 2, ...), and the same signal is supplied to the transparent display electrode connected to the drain electrode to operate the liquid crystal. To display one pixel. Therefore, as long as no malfunction occurs in the four TFTs, it has an effect of reducing the point defect defect of the pixel.

Further, as described above, the source electrode of the TFT is alternately connected to the left and right of the column wiring for every two row wirings.
Since the pixel is horizontally displaced by one transparent display electrode with respect to the vertically adjacent pixel (see FIG. 1), it is possible to suppress moire-shaped display fixed pattern noise.

Further, according to the present embodiment, the same circuit as the drive circuit of the conventional low density pixel liquid crystal panel of 350 × 240 pixels is used to suppress the pattern noise and reduce the point defect defect. Has the advantage that

On the other hand, as shown in FIG. 2, the row wirings X2 _2n-1 , X2 _2n (n = 1, 2, ...) Of the above-mentioned active matrix substrate.
And the chromium wiring shorting the column wirings Y2 _2n-1 , Y2 _2n (n = 1, 2, ...) Is removed by etching, and the column wiring,
A TFT can be driven independently without short-circuiting row wirings, and a liquid crystal panel in which one transparent display electrode connected to the drain electrode of the TFT corresponds to one pixel is configured. That is, a liquid crystal display device of a high-density pixel liquid crystal panel of 700 × 480 pixels can be realized.

As described above, in this embodiment, the number of row wirings and column wirings of the active matrix substrate for the high density pixel liquid crystal panel is two.
Since the low-density pixel liquid crystal panel and the high-density liquid crystal panel can be manufactured on the same active matrix substrate simply by short-circuiting or not short-circuiting for each line, the production process of the active-matrix substrate can be unified and therefore the production cost can be reduced. Also has.

 Next, another embodiment of the present invention will be described.

FIG. 3 shows an equivalent circuit diagram of the active matrix substrate of the liquid crystal panel portion of the liquid crystal display device of this embodiment. Glass plate
48 1 row wiring 32 (X3 _{0 to} X3 ₄₈₀ ) on 31 and 700 column wiring
A TFT 34 is formed at each position where 33 (Y3 _{1 to} Y3 ₇₀₀ ) intersect by connecting the gate electrode to the row wiring and the source electrode to the column wiring, and the transparent display electrode 35 for applying a voltage to the liquid crystal is formed on the TFT 34. It is formed so as to be connected to the drain electrode. At this time, as shown in the figure, the source electrode of each TFT 34 is connected so that a signal can be supplied to the transparent display electrode located on the right side of the column wiring. Then, for every two column wirings, that is,
Y3 _2n-1 , Y3 _2n , (n = 1, 3, ..., 349) Column gates are connected to the source electrodes of the TFT gate electrodes, and the transparent display electrodes located below the row lines are signaled. So that they can be supplied, and then the next two row wirings Y3 _{2n + 1} , Y3 _{2 (n + 1)} ,
The gate electrode of the TFT having the source electrode connected to (n = 1, 3, ..., 349) is connected to the transparent display electrode located above the row wiring so that a signal can be supplied. In this manner, the lower and upper sides are alternately repeated to connect the gate electrodes. Further, row wirings X3 _2n-1 and X3 _2n (n = 1, 2,
...) and column wiring Y3 _2n-1 and Y3 _2n (n = 1, 2, ...
・) And () are short-circuited by a short-circuit wire 36 such as chromium which can be removed by etching.

In the liquid crystal display device of this example, red, green, and blue color filters were formed using the above-mentioned active matrix substrate so that four transparent display electrodes surrounded by broken lines in FIG. 3 would form one pixel. The counter substrate and the counter substrate are made to correspond to each other. That is, a liquid crystal display device of a low density pixel liquid crystal panel of 350 × 240 pixels is realized.

In the liquid crystal display device having such a configuration, the short-circuited row wirings X3 _2n-1 and X3 _2n (n = 1, 2, ...) And the column wiring Y3
_4n TFTs are driven simultaneously by _2n-1 and Y3 _2n (n = 1, 2, ...), and the same signal is supplied to the transparent display electrode connected to the drain electrodes to operate the liquid crystal. To display one pixel. Therefore, this embodiment also has the effect of reducing the point defect defect of the pixel unless the operation defect of the four TFTs occurs.

In addition, as described above, by connecting the gate electrodes of the TFT alternately every two column wirings below and above the row wiring,
Since the pixels are vertically displaced by one transparent display electrode with respect to the adjacent pixels on the left and right (see FIG. 3), it is possible to suppress moire-shaped display fixed pattern noise.

Further, according to this embodiment, as in the first embodiment, the same circuit as the driving circuit of the conventional low density pixel liquid crystal panel of 350 × 240 pixels is used to suppress the pattern noise and reduce the point defect defect. It has an advantage that a liquid crystal display device with low density pixels can be constructed.

On the other hand, as shown in FIG. 4, the row wirings X3 _2n-1 , X3 _2n (n = 1, 2, ...) Of the above-mentioned active matrix substrate.
And the chromium wiring shorting the column wirings Y3 _2n-1 and Y3 _2n (n = 1, 2, ...) Is removed by etching to remove the column wiring,
A TFT can be driven independently without short-circuiting row wirings, and a liquid crystal panel in which one transparent display electrode connected to the drain electrode of the TFT corresponds to one pixel is configured. That is, a liquid crystal display device of a high-density pixel liquid crystal panel of 700 × 480 pixels can be realized.

As described above, also in this embodiment, the number of row wirings and column wirings of the active matrix substrate for the high-density pixel liquid crystal panel is two.
Since the low-density pixel liquid crystal panel and the high-density liquid crystal panel can be manufactured on the same active matrix substrate simply by short-circuiting or not short-circuiting for each line, the production process of the active-matrix substrate can be unified and therefore the production cost can be reduced. Have.

Although the two embodiments of the present invention have been described focusing on short-circuiting two row wirings and two column wirings, the same effect can be expected by short-circuiting either one of the row wirings and the column wirings. Further, it goes without saying that the same effect can be obtained for a liquid crystal display device configured by using an active matrix substrate capable of short-circuiting more than two wires.

Furthermore, non-TFT non-linear elements such as metal-insulating film-
The present invention is also effective for a liquid crystal display device configured by using an active matrix substrate on which metal elements, ring diodes, etc. are formed.

Next, a method for manufacturing the liquid crystal display device of the present invention will be described below.

In this embodiment, a high density pixel liquid crystal panel of 700 × 480 pixels having an equivalent circuit of the active matrix substrate shown in FIG. 2 is constructed. That is, this panel is a liquid crystal panel equivalent to the case where the column wiring and the row wiring are not short-circuited in the first embodiment.

First, the image display performance of this liquid crystal panel is inspected, and if there is no point defect defect due to TFT defect etc. as a result of the inspection, it is used as it is as a high density pixel liquid crystal panel. On the other hand, if there are many point defect defects, the row wirings X2 _2n-1 and X2 _2n (n =
, 2, ..., and column wiring Y2 _2n-1 and Y2 _2n (n = 1,
2, ...) and short-circuit the wirings respectively connected to. As a result, a low-density pixel liquid crystal panel which is equivalent to the equivalent circuit shown in FIG. 1 and in which point defect defects are hardly noticeable is constructed.

As described above, according to the present invention, since it is possible to allocate to either the high-density pixels or the low-density pixels according to the image display performance after the high-density pixel liquid crystal panel is configured, there is an effect that the production cost of the liquid crystal panel can be comprehensively reduced. .

EFFECTS OF THE INVENTION As described above, the present invention short-circuits a fixed number of row wirings, column wirings, or both wirings of an active matrix substrate for a high-density pixel liquid crystal panel, and simultaneously drives a non-linear element in a fixed section. Then, by manufacturing a low-density pixel liquid crystal panel with a structure in which one pixel is displayed by a plurality of transparent display electrodes connected to the non-linear element, a point defect failure caused by a non-operational operation of the non-linear element can be prevented from occurring. This has the effect of reducing it by using a driving circuit for a low-density pixel liquid crystal display device.

Further, if the row wiring and the column wiring are not short-circuited, the high-density pixel liquid crystal panel can be constructed using the same active matrix substrate. That is, since the active matrix substrates for the high-density pixel liquid crystal panel and the low-density liquid crystal panel can be manufactured in the same process, the production cost can be reduced. Furthermore, by performing a short-circuiting process after the inspection of the image display performance, it is possible to sort the liquid crystal panel for high-density pixel liquid crystal panel and for low-density pixel liquid crystal panel according to the degree of point defect defect, so that the liquid crystal display is comprehensively displayed. It also has the effect of reducing the production cost of the device.

[Brief description of drawings]

1 and 2 are equivalent circuit diagrams of the liquid crystal panel portion of the liquid crystal display device according to the first embodiment of the present invention, FIG. 3 and FIG.
FIG. 5 is an equivalent circuit diagram of a liquid crystal panel portion of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 5 is an equivalent circuit diagram of a conventional liquid crystal panel portion. 1, 21, 31 …… Glass substrate, 2, 22, 32 …… Row wiring,
3,23,33 …… Column wiring 4,24,34 …… TFT, 5,25,3
5: Transparent display electrode.

 ─────────────────────────────────────────────────── --- Continuation of front page (56) Reference JP-A-57-49994 (JP, A) JP-A-63-71882 (JP, A) JP-A-61-213880 (JP, A) JP-A-61- 97626 (JP, A) JP 59-9636 (JP, A)

Claims (1)

(57) [Claims] 1. A plurality of column wirings and a plurality of row wirings, a non-linear element connected so as to supply a signal from the wiring to each position where these wirings intersect, and a transparent connected to these non-linear elements. The first substrate on which the display electrodes are formed and the second substrate on which the transparent counter electrode is formed are the main surfaces on which the respective transparent electrodes of the first and second substrates are formed are the inner surfaces facing each other. A liquid crystal display device having a liquid crystal panel in which liquid crystals are sandwiched in the facing space as described above, and a signal can be supplied to a transparent display electrode located in either of the following (a) or (b) order. The non-linear element is connected to a column wiring or a row wiring, and (a) the non-linear element is provided so that a signal can be supplied to a transparent display electrode located above or below the row wiring of the first substrate. Connect the elements to the row wiring and In a left-right alternating order with respect to the column wiring with a fixed number of as a repeating unit, (b) a signal is transmitted to the transparent display electrode located on either the left side or the right side of the column wiring of the first substrate. The non-linear element is connected to the column wiring so that it can be supplied, and the column wiring or the row wiring, or both of them are fixed in a fixed order with respect to the row wiring with a fixed number of column wiring as a repeating unit. Repeatedly short circuit for each number to supply the same signal,
A liquid crystal display device comprising a short-circuit wiring for simultaneously driving a fixed number of the non-linear elements.