JPH01130131A - Driver-containing active matrix panel - Google Patents

Abstract

PURPOSE:To produce a defectless panel suitable for data display at a high yield by providing two TFTs (thin film transistors) to respective picture elements and providing build-in drivers which are capable of respectively independently driving signal lines of odd rows and signal lines of even rows to the panel. CONSTITUTION:A picture element area 1 consists of 2M-pieces of the signal lines and N-pieces of scanning lines as well as (MXN) pieces of picture element electrodes and the two picture element TFTs 10 in which the drain electrode is commonly connected to one of the respective picture element electrodes. The gate electrodes of the picture element TFTs are connected to the common scanning line and the source electrodes are connected to the adjacent two signal lines. The signal lines X1a-XMa of the add rows are driven by the X driver 2 and the signal lines X1b-XMb of the even rows are driven by the X driver 3. All the scanning lines Y1-YN are driven by the Y driver 4. Different signals can, therefore, be applied to the two TFTs 10 by using the built-in drivers 2-4 to detect a defective part. The defective part is corrected by laser trimming, etc. The defectless panel suitable for data display is thereby produced at the high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of an active matrix panel with a built-in driver.

[Conventional technology]

Examples of conventional active matrix panels with built-in drivers include rsID (Nisu Eye Fist Day) 84 Digest P, 316 Ryojiku, etc. FIG. 2 is an example of the circuit diagram. 21 is a pixel area, 22 is an X driver, and 24 is a Y driver. The pixel area 21 receives signals nx1, x*s
It consists of a pixel TFT 30 arranged at the intersection of Y*, YN1, and Hisoh.

A pixel electrode is connected to the pixel TFT 30, and a counter electrode VC
A capacitor 31 exists between 8 and 4. 82 is the capacitance between the signal line and the opposing W1 pole. The X driver 22 consists of a shift register 26 and an analog switch TFT 28. VID is a pixel signal input terminal, CLX and CLY are clock signals, and DX and DYl are driver operation input signal terminals.

[Problem that the invention seeks to solve]

However, the above-mentioned prior art has the following problems. In other words, the active matrix panel is
It is necessary to produce tens of thousands to millions of active elements over a large area, and it is essentially extremely difficult to produce a defect-free panel. In particular, as the screen size increases and the screen definition increases, the yield rate further decreases.

On the other hand, when an active matrix panel is used to display data such as characters, it is necessary not only to be defect-free but also to display gradations that are faithful to the signals applied to all pixels. It is almost impossible to make such panels using conventional techniques.

The present invention is intended to solve these problems, and its purpose is to manufacture a defect-free active matrix panel suitable for data display with a built-in driver at low cost and high yield. It's there.

[Means for solving problems]

The active matrix panel with a built-in driver of the present invention is characterized by having the following configuration.

N scanning lines, 2M signal lines, M×N pixel electrodes, and two TFTs each having a drain electrode commonly connected to one of the pixel electrodes, and a gate of the two TFTs. The electrodes are connected to a common scanning line, the source electrodes are connected to two adjacent signal lines, and the device is equipped with a built-in driver that can independently drive the signal lines in odd-numbered columns and the signal lines in even-numbered columns.

[Effect]

The active matrix panel with a built-in driver using the above configuration of the present invention has redundancy in the pixel TFT and signal line, and if either of the two TFTs in each pixel is normal, a normal signal is given. be able to. On the other hand, different signals can be applied to these two TFTs using built-in drivers, and the address of the defective TFT can be easily detected electrically and optically.

〔Example〕

FIG. 1 is an example of a circuit diagram of an active matrix panel with a built-in driver showing one embodiment of the present invention. The active matrix panel with a built-in driver consists of a pixel area 1, an X driver 2.3, and a Y driver 4. In this embodiment, there is redundancy in the signal lines and pixel TFTs, and pixel area 1 has 2M signal lines, N scanning lines, M×N pixel electrodes, and a drain on one of each pixel electrode. The pixel TFT 10 has a gate electrode connected to a common scanning line and a source electrode connected to two adjacent signal lines. 11 is a pixel electrode and a counter electrode V; . 12.13 is the capacitance of the liquid crystal between the signal line and VcoM.

In order to improve the signal retention characteristics, a capacitor may be added in parallel to these capacitors. Odd column signal n
, n , Xs a 1XM w is the X driver 2, the even-numbered column signal lines Xtb%X, h, and XHh are the X driver 3, and the scanning lines Y1, Yl, and YN are all the Y driver 4.
Drive with. The X driver 2.3 is a shift register 6.
7 and an analog switch TFT array 8.9.

A latch circuit can be provided in place of this analog switch to provide a line sequential driver. CLxas CL
xb is the clock input terminal of shift register 6.7, DX
axDXb is a start signal input terminal of the shift register 6.7, and VIDalVIDb is an image signal input terminal.

Y driver is shift register, CLY is clock,
DY is an input terminal for a start signal.

In this example, one pixel has two TFTs, so even if one of the TFTs is defective, if the other TFT is normal, the defective TFT can be cut off using laser trimming or the like. It can be fixed. Since a regular signal is given to the corrected pixels, in this embodiment, a defect-free active matrix panel that can also display data such as characters can be manufactured at a high yield. On the other hand, when detecting the address of a defective part, this embodiment has redundancy in the signal lines and can drive the signal lines in odd-numbered columns and even-numbered columns independently, so it can be easily detected electrically or optically. Can be detected. The specific method will be explained below.

The first method is an electrical detection method.

There are generally two modes of TFT failure: seat and open, but since there is no particular need to correct the latter, the method for detecting the former will be described. FIG. 3(a) shows a method for detecting short-circuits between the gate and source and between the gate and drain of a TFT. As shown in this figure, if you select the scanning lines in sequence, connect an ammeter to each of the image signal input terminals VIDa and VIDb, and select the signal lines in sequence, you can easily find the shorted address. . Which of the two TFTs is short-circuited is determined based on the magnitude of the detected current value. Note that it takes a considerable amount of time to perform this measurement on all addresses, so first select all the scanning lines and signal lines at the same time, and if a leakage current is detected, select the scanning lines one by one one by one.
An efficient method is to stop the operation of the Y driver at the scanning line where leakage current is detected again, select the signal lines one by one, and obtain the address. FIG. 3(b) shows a method of detecting a sheet between the source and drain of a TFT, and the series resistance of two TFTs is determined. If either TF
If the source and drain of T are short-circuited, this resistance will be approximately halved. However, since it cannot be determined implicitly which of the two TFTs is defective, it is necessary to investigate by visual inspection or by directly probing the pixel electrode.Normally, a short between the source and the drain is a pattern defect in the top view. Since this is the main problem, it can often be resolved through a visual inspection. Third
Figure (C) shows a method for determining short circuits between signal lines rather than defects in TFTs. When the signal lines are provided with redundancy as in this embodiment, a short circuit may occur between the two signal lines between the pixel electrodes. Such defects can be detected by sequentially selecting two adjacent signal lines as shown in this figure and detecting the leakage current between the signal lines. In this case, it is impossible to electrically determine the address on the Y side, but since pattern defects are the main cause of ml, visual inspection shows
You can find out where it is and make corrections.

The second method is an optical detection method. This inspection is performed after the liquid crystal is sealed. This method is simple, and if A is the case where an image is displayed using only X Driver 2, and B is a case where an image is displayed uniformly using only X Driver 3, compare A and B and see if the image is defective. This method involves finding the TFT address.

A cross-sectional view of the active matrix substrate is shown in FIG. 4
0 is an insulating substrate, 41 is a gate electrode, 42 is a gate insulating film, 43 is a channel portion, 44 and 45 are source and drain electrodes, 46 is an interlayer insulating film, 47 is a signal line, and 48 is a pixel electrode. The TFTs that make up the built-in driver have the same structure and are manufactured at the same time as the pixel TFTs.

〔Effect of the invention〕

As mentioned above, Honjomei's active matrix panel with a built-in driver has redundancy in the pixel TFT and signal line, and if either of the two TFTs in each pixel is normal, the normal signal will be output. On the other hand, different signals can be given to these two TFTs using the built-in p-river, and the address of the defective TFT can be easily determined electrically and optically. . Therefore, by detecting the defective portion using the built-in driver and correcting it by laser trimming or the like, it is possible to produce a defect-free active 4-trix panel suitable for data display at a high yield. In particular, for high-definition panels, such inspection is impossible with normal inspection methods using probe cards, etc., but according to the present invention, the driver can be operated as much as possible even on very high-definition panels. I can handle it. Furthermore, the time required for inspection is short, and costs do not increase. Additionally, since the driver is built-in, the panel is small and lightweight, and manufacturing costs are low.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of an active matrix panel with a built-in driver. Figure 2 is a circuit diagram of a conventional active matrix panel with a built-in driver. FIGS. 3(a), 3(b), and 3(c) are diagrams showing a method of detecting a defective part. FIG. 4 is a cross-sectional view of the active matrix substrate. 1.21... Pixel area 2.22... X driver 4.24... Y driver 6.7.26... Shift register 8.9.28... Analog switch TFT 10.30
... Pixel TFT Applicant: Seiko Epson Corporation"; , -: $2 Figure (shi) (go)

Claims (2)

[Claims] (1) A thin film transistor provided on an insulating substrate, including a plurality of data line groups, a plurality of scanning line groups, and a driver for driving at least one of the data line and the scanning line, and provided at an intersection of the data line and the scanning line. (hereinafter abbreviated as TFT)
An active matrix panel with a built-in driver comprising an array that drives pixel electrodes and drives a liquid crystal, the active matrix panel with a built-in driver having the following configuration. N scanning lines, 2M signal lines, M×N pixel electrodes, and two TFTs each having a drain electrode connected to one of the pixel electrodes in common. The gate electrode is connected to a common scanning line, the source electrode is connected to two adjacent signal lines, and it has a built-in driver that can independently drive the odd-numbered and even-numbered signal lines. . (2) T constituting the pixel TFT and built-in driver
2. The active matrix panel with a built-in driver according to claim 1, wherein the FT is formed using a polysilicon thin film.