JPH01933A - display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a display device using a thin film transistor (TFT) array as a drive circuit, and particularly relates to a display device that uses a thin film transistor (TFT) array as a drive circuit, and is particularly concerned with increasing the area and increasing the resolution. The present invention relates to reducing pixel defects due to TFT short-circuit defects.

[Conventional technology]

Such a display device is usually constructed by a method in which a display material such as a liquid crystal is sandwiched between two opposing substrates, and a voltage is applied to the display material. At this time, at least one substrate is provided with poles of *#J elements arranged in a matrix pattern, and in order to selectively operate these pixels, an element having nonlinear characteristics such as a field effect transistor (FET) is used. Mutsuko Motoko is doing well.

By the way, in this type of device, short-circuit defects in active elements are applicable lI! This has the problem of creating an opportunity for elemental defects. As a method for compensating for pixel defects (defects) due to defects in active elements, there is one method, for example, disclosed in Japanese Patent Application Laid-Open No. 60-97322.
As shown in the publication, conventionally a plurality of active elements (T
(FT), a method was used in which one pixel was constructed from a set of display electrodes. Figure 2 is.

This shows a compensation method for pixel defects using this conventional method.
The configuration of the FT array substrate is shown.

In Figure 2, (IA), (IB), (lC)
and (ID) are TFTs, (2A) and (2B) are gate electrode lines, and (3A) and (3B) are source electrode lines. Also, (4A).

(4B), (4C) and (4D) are the respective TFs
These are display electrodes corresponding to T, and these four display electrodes form one pixel.

With this configuration, for example, even if T P T (IA) is defective, the remaining T P T (IB) ~ (
ID) is normal, this pixel has an area of 3 compared to normal.
/4 +Nlt, and can prevent defects from becoming noticeable.

[Problem that the invention seeks to solve] A conventional display device is configured as described above.

Both the gate electrode line and the source electrode edge have the originally required number of 2.
There is a problem that twice as many pixels are required, and since a space is required to separate these electrode lines and display electrodes, there is a problem that the effective area for one pixel is reduced. What are the problems with these?

This also eliminates the advantage of being able to compensate for defective pixels, and for this reason, there has been no practical method for compensating for defective pixels.

This invention was made in order to solve the above-mentioned problem, and is a TFT that can compensate for defective pixels with a simple configuration.
The purpose is to obtain a matrix type display device using an array.

[Means for solving problems]

In the display device according to the present invention, one display electrode (IiI
Two TFTs are provided per i element, and these are connected in a Darlington manner.

[Effect]

In this invention, one display electrode is connected to two
I arranged it to be driven by two TFTs.

Even if a short circuit defect occurs in either TFT.

By cutting off the connection to the source electrode of the TFT, the remaining TFT can drive the display electrode.

〔Example〕

Figure IA1 is a schematic diagram showing the TFT A of one embodiment of the present invention, (La) and (Ib) are Darlington connected iJ1 and the second TFT, and the rest is the same as the conventional example in Figure 2. , (2) is the gate electrode a[, 13) is the edge of the source electrode, and (4) is the display electrode.

In this configuration, if there is no abnormality in the TFT.

When the gate electrode edge (2) and the source electrode line (3) are selected, first, 1! TF'T (la) of l is on (ON)
Next door.

The second T P T (lb)
is turned on, the first and second T P T (1!LJ, (tb
) is transmitted through the display electrode (4).

In this configuration, a short circuit between the gate electrode and the source electrode of T P T (m) of @l and a short circuit between the gate electrode and the drain electrode are S;t'r F T (la) of the source electrode Therefore, by using a $1 TFT (la) as a two-terminal element, the gate signal is 11g2 T P T (l
b) to the gate electrode of IA2, T F T (
lb) transmits the signal of the source electrode line (3) to the display IE pole (4).

Roughly speaking, a short circuit between the gate electrode and source electrode of the second T P T (lb) and between the gate electrode and drain electrode is as follows.
By electrically separating the source electrode of the second TFT (To) from the source electrode line (3), the signal at the drain of @l's rii'T (la) is displayed as a two-terminal element by '4 poles ( 4) Used to communicate.

The defect location can be determined by measuring the resistance between the gate electrode 51 (2) and the source electrode @ (3), as shown in Part 1. A short circuit between the source electrode and the gate electrode of 2 T . Further, a short circuit between the gate electrode and the drain electrode can be determined by an increase in the current flowing through the source electrode kC@ when a voltage is applied to the 112 TFTs (lb) + 1 display electrode (4). First T P T (
la) Even if there are many problems, it can be determined by the increase in the current flowing through the source electrode @ (3) when a 4C signal is applied only to the gate electrode # (2).

〔Effect of the invention〕

As described above, in the present invention, by providing two TFTs in one pixel and using a Darlington connection, it is possible to easily compensate for pixel defects caused by short-circuit defects in TFTs.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a TFT eye according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a TFT array of a conventional display device. In Figure 1, + (Ia) is the igt TFT, (lb
) is the second TFT, +2) is the gate electrode line, and (3) is the source electrode line. (4) is a display electrode. Note that the same reference numerals in Figure 1 indicate the same or equivalent parts.

Claims (1)

[Claims] (1) At each intersection of a plurality of gate electrode lines and a plurality of source electrode lines perpendicular to the gate electrode lines, a display electrode of a pixel is connected, and a thin film transistor (hereinafter abbreviated as TFT) that drives each of the display electrodes is attached. in a matrix type display device in which a plurality of TFTs are arranged, first and second TFTs are provided as the TFTs for each pixel, and the gate electrode of the first TFT is connected to the gate electrode line;
The source electrodes of the first and second TFTs are both connected to the source electrode line, the drain electrode of the first TFT is connected to the gate electrode of the second TFT, and the drain electrode of the second TFT is connected to the display electrode. A display device characterized by being connected to.