JPH01297627A - Reflection type active matrix and correction method thereof - Google Patents

Abstract

PURPOSE:To enable correction in such a manner that the matrix array appears to be visually entirely defectless when videos are displayed by constituting switching elements cuttably and forming the connecting electrodes connected to the switching elements driving adjacent reflecting electrodes. CONSTITUTION:A wiring 6 or the terminal of the switching element is so cut that a voltage is not impressed to the reflecting electrode 8 driven by the defective switching element when this switching element is defective. The connecting electrode 10 and the reflecting electrode 8 are then connected by irradiating the connecting electrode 10 formed under the cut reflecting electrode 8 with a laser. The voltage is, therefore, impressed to the electrode 8 by the switching element driving the electrode 8 adjacent thereto and the one switching element impresses the voltage to the two electrodes 8. Since the adjacent picture elements are substantially the same in color and brightness, the picture elements appear to be visually normally lighted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an active matrix array used in an active matrix type liquid crystal display device and a method for modifying the same.

Conventional technology In recent years, the number of scanning lines has increased as the number of picture elements in type liquid crystal display devices has increased, and the display contrast and response speed of conventional simple matrix liquid crystal display devices have decreased. Active matrix array pear-shaped liquid crystal display devices in which elements are arranged are being used. There are two types of active matrix liquid crystal display devices: a transmissive type that displays by transmitting light, and a reflective type that displays by reflecting light. A transmissive active matrix array is used for a transmissive active matrix liquid crystal display device, and a reflective active matrix array is used for a reflective active matrix array liquid crystal display device. However, in an active matrix array, tens of thousands or more switching elements for driving picture elements, such as thin film transistors (hereinafter referred to as TPT), must be formed on a single substrate. Therefore all T
It is difficult to form PT without defects. Therefore, an array and a modification method that can improve the yield by modifying the manufactured active matrix array have been awaited.

Next, defects in TPT will be explained. Here, the description will be made assuming that the drain terminal of the TPT is connected to the reflective electrode. There are three types of TPT defects. The first is TP
This is a short circuit defect between the source and gate of T, and the display mode is called a line defect. The second type is a TPT gate-drain short circuit defect, which becomes a pixel defect called a black defect in display. Finally, the TPT source
This is a drain-to-drain short circuit defect, and the display becomes a pixel defect called a white defect. The above-mentioned defects deteriorate the display quality of the type liquid crystal display device and therefore need to be corrected.

A conventional reflective active matrix array will be described below. FIG. 16 is a plan view of a conventional reflective active matrix array.

Moreover, FIG. 17 (al is a cross-sectional view taken along the JJ' line in FIG. 16, and FIG. 17 (g) is a cross-sectional view taken along the KK'' line in FIG. 16. In (b), 1 a + 1 b + 1 c is a source signal line,
2a-2c are gate signal lines, 3a, 3b, 3c, 3d are TFT source terminals, 4a, 4b, 4c, 4d are TFTs
5a, 5b, 5c, 5d are TFT drain terminals, 7a, 7b, 7c, 7d are contact holes for connecting the reflective electrode and the drain terminal, 8a, 8
b, 8c, and 8d are reflective electrodes, 11 is an insulating substrate, and 12 is an insulating film. Here, there are enlarged or reduced portions in the drawing of the reflective active matrix array. Further, the same applies to the following drawings, in which the surface on which the reflective electrode is formed is referred to as the front surface, and the insulating substrate is referred to as the back surface.

In a conventional reflective active matrix array, a TPT is configured with a source terminal connected to a source signal line, a gate terminal connected to a gate signal line, and a drain terminal, and the drain terminal is connected to a reflective electrode through a contact hole. .

The TPT is controlled by signals applied to the gate signal line and the source signal line, and a predetermined voltage is applied to the reflective electrode.

FIG. 18 is an equivalent circuit diagram of a conventional reflective active matrix array. In FIG. 18, G, ~G are gate signal lines, S, ~S3 source signal lines, TII ~ T4S
is a TFT, and P, . . . -P43 are reflective electrodes. Also the first
FIG. 9 is a cross-sectional view of the reflective active matrix array after it has been assembled into a liquid crystal display device by attaching a counter electrode substrate and the like. In FIG. 19, 27 is an alignment film formed on the surface of the reflective electrode, 28 is a liquid crystal, 31 is a transparent substrate such as glass, and 30 is an IT layer formed on the transparent substrate 31.
The transparent electrode 29 made of O is an alignment film formed on the transparent electrode 30. In operation, the liquid crystal 28 changes depending on the voltage applied to the reflective electrode. Light incident from the glass substrate 31 is polarized by the liquid crystal 28 and reflected by the reflective electrode. An image is projected by the reflected light.

Next, a method of modifying a conventional active matrix array will be explained. When a defect occurs in TPT, a method has been used to make it a black defect that is relatively hard to notice. The above repair method involves irradiating the TPT with a laser or the like.
This was done by breaking the

Problems to be Solved by the Invention However, with conventional active matrix play and its repair method, only line defects and white defects can be turned into black defects. The black defect is, of course, a defect and significantly deteriorates display quality. In addition, in order to break the entire TPT, a laser or other device is used to destroy the TPT.
There is a very high risk that the constituent materials of the PT will peel off and cause a short circuit with the upper reflective electrode. If the aforementioned short circuit occurs, it will most likely result in a line defect and there is no way to save the array.
Furthermore, depending on the laser irradiation state, the TPT gate becomes floating, which often makes the state worse than before the laser irradiation. Therefore, at present, almost no correction has been made in conventional reflective active matrix arrays. Therefore, the yield is very poor (,
When the cost becomes high and the number of picture elements exceeds tens of thousands, it is impossible to manufacture all TPTs on one array without defects.

In view of the above-mentioned problems, the present invention provides a reflective active matrix array and a method for correcting the same, which can be corrected so that when an image is displayed, it appears to be visually defect-free.

Means for Solving the Problems In order to solve the above problems, a reflective active matrix array of the present invention includes a first wiring connecting one terminal of a switching element and a reflective electrode, and a first wiring connecting one terminal of a switching element and a reflective electrode adjacent to the reflective electrode. The device includes a connection electrode formed in a lower layer via an insulating film, and a second wiring that electrically connects the first wiring and the connection electrode.

Further, the method for repairing a reflective active matrix array of the present invention includes electrically cutting the terminals of the switching element or the first wiring using at least one of optical and thermal processing means. electrically connecting the second wiring and the reflective electrode by melting or vaporizing the constituent material of the connection electrode formed in the lower layer of the reflective electrode connected to the first wiring. It is.

Function The reflective active matrix play of the present invention has a first wiring connecting the drain terminal of the switching element and the reflective electrode, which is also formed in a conventional reflective active matrix play, and a lower layer of the adjacent reflective electrode. A second wiring is provided to connect the drain terminal to a connection electrode formed so as not to be electrically connected to the reflective electrode.

If the switching element is defective, first the first wiring or the terminal of the switching element is cut off so that no voltage is applied to the reflective electrode driven by the switching element. Next, a laser beam or the like is irradiated onto the connecting electrode formed under the cut reflective electrode to connect the connecting electrode and the reflective electrode. Then, a voltage is applied to the reflective electrode by a switching element that drives a reflective electrode adjacent to the reflective electrode. In other words, one switching element applies voltage to two reflective electrodes. The display state is that the picture elements located on the two reflective electrodes are as shown in the figure.
However, in the case of moving images such as television images, most of the adjacent picture elements have the same color and brightness, so visually they appear to be normal lights. Further, since the driving capacity of a switching element is usually designed to be large, one switching element can sufficiently drive two reflective electrodes.

EXAMPLE Hereinafter, an active matrix array according to a practical example of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of the reflective active matrix array of the present invention as viewed from the surface. Also, Figure 2(a)
is a cross-sectional view taken along line AA' in FIG. 1, and FIG. 2(b) is a cross-sectional view taken along line BB'' in FIG.

1 and 2 (a) and (b), 11 is an insulating substrate such as glass, 1a to 1c are source signal lines, and 2a
-2b are source signal lines, 3a-3d are TFT source terminals, 4a-4d are TFT gate terminals, 5a-5d are TFT
Drain terminal of FT, 6a to 6d are wiring for connecting the drain terminal of TFT and reflective electrode (hereinafter referred to as reflective electrode wiring), 73 to 7d are contact holes, 8a
8f is a reflective electrode, 10a to 10d are electrodes formed under the adjacent reflective electrodes (hereinafter referred to as connection electrodes),
Wirings 9a to 9d (hereinafter referred to as connection wirings) electrically connected to the connection electrodes 10a to 10d and the drain terminal of TPT, etc. 12 are insulating films made of S, Nx, or the like.

As is clear from FIG. 1 and FIGS. 2(a) and 2(b), the drain terminal of the TPT is connected to the reflective electrode by the reflective electrode terminal, and is also connected to the connecting electrode by the connecting wire. The connection electrode is formed of a metal thin film such as T1, A2, Cr, etc., and its thickness is required to be 500 Å or more, preferably 2000 Å or more. Furthermore, constrictions are formed at the gate/source terminals and reflective electrode terminals of the TPT. Further, the constriction is for improving cutting performance by the processing means, and when the processing means is a laser or the like, it is preferable to form the constriction to be narrower than the beam diameter of the laser.

In the method for manufacturing a reflective active matrix array of the present invention, after forming TFTs, connection wiring, etc. on an insulating substrate 11, an insulating film such as 5INx is formed. Next, a contact hole is formed, and then a thin film mainly made of Al is formed to form a reflective electrode. Finally, the reflective N pole is separated from adjacent picture elements by etching to complete the process.

FIG. 3 is an equivalent circuit diagram of a reflective active matrix array in the first embodiment of the present invention. In FIG. 3, 13 is a TFT, 14 is a source signal line, 15 is a gate signal line, 16 is a connection wiring, and 1 is a connection electrode.

Each T'FT 13 is connected to a reflective electrode 17, and is also connected to a connection electrode formed in the lower layer of the reflective electrode adjacent to the lower side of the reflective electrode. Although it is assumed that the reflective electrode wiring is formed, this may be considered to include the drain terminal of the TPT.

Next, a method for modifying a reflective active matrix array according to the present invention will be explained. First of all, Figure 4 shows the BB of Figure 1.
It is a sectional view taken along the line '. In Figure 4, 19 is YAE
In order to modify the reflective active matrix array of the present invention, a processing means (not shown) is used to modify the reflective active matrix array of the present invention. ) is transmitted through the insulating substrate 11 to heat the constituent material at the processing position. FIG. 5 shows a plan view of a reflective active matrix array. In FIG. 5, 20 and 21 are light irradiation positions (hereinafter referred to as irradiation positions), and 13a and 13d are TFTs. In addition, FIG. 5 shows the repair performed when a source-drain short circuit defect (hereinafter referred to as a white defect) or a gate-drain short circuit defect (hereinafter referred to as a black defect) occurs in the TPT 13d. There is.

First, the reflective electrode wiring 6d is cut at the irradiation position 21 so that no voltage is applied to the reflective electrode 8d from the defective TFT 13d. During the cutting, the power of the light beam is made as low as possible so as not to cause a short circuit to the reflective electrode 8d formed in the upper layer, and the same spot is irradiated multiple times. When a laser is used as the processing means, it is preferable to use a laser with a wavelength that is difficult to be absorbed by the refined substance of the reflective electrode wiring, and a YAG laser or the like is most suitable. Further, it is preferable to irradiate the irradiation position 21 with two or more pulses for cutting, and preferably adjust the laser power so that cutting can be performed with five or more pulses.

Next, irradiate the laser beam on the irradiation position 20 and connect? ? connects the pole 10a and the reflective electrode 8d formed in the upper layer.

When a laser is used for the processing, a wavelength that is easily absorbed by the refined substance of the connection electrode is preferable, and a second high wave of a YAG laser is most suitable. Further, better connection can be achieved by increasing the energy per pulse of the laser power and reducing the number of pulses as much as possible. Also,
A YAG laser with a diameter of 1.06 μm may be used, but in that case, a laser power approximately twice as high as the laser pulse applied to the irradiation position 21 may be applied.

In other words, when processing the irradiation position 21, a weak laser power is applied multiple times to evaporate the constituent material at the position as much as possible, and when processing the irradiation position 20, a strong laser power is applied and the constituent material is Evaporate and connect the electrodes! , connect it to the reflective electrode by separating it.

FIGS. 7(a) and 7(b) are cross-sectional views of the reflective active matrix array after the modification is completed. In addition,
FIG. 7(a) is a sectional view taken along line CC' in FIG. 5, and FIG. 7(■) is a sectional view taken along line DD' in FIG. Figure 7(a)
, ■), the processing position 21 is electrically connected, and the irradiation position 20 breaks the insulator film 20,
It is connected to a five-layer reflective electrode 8d.

Although the irradiation position 21 is processed first and the irradiation position 20 is processed next, it goes without saying that the order of the steps may be reversed. Further, if a gate-source short circuit defect (hereinafter referred to as a line defect) occurs in the TFT 13d, the source terminal 3d and the gate terminal 4d or drain terminal 5d of the TFT 13d are disconnected.

The above correction method is also applicable to the reflective active matrix array of the invention described below.

A reflective active matrix array according to a second embodiment of the present invention will be described below. FIG. 8 is a plan view of a reflective active matrix array in a second embodiment of the present invention. In the second practical example, the connection electrode 10a-1
Thin films 22a to 22d (hereinafter referred to as metal thin films) made of a metal having a boiling point different from that of the electrode material are formed on 0b. A thin film preferably made of A2 is formed.

FIG. 9 is a sectional view taken along line EE' in FIG. 8. The thin film has a thickness greater than that of the connection electrode.

A method for modifying a reflective active matrix array according to a second embodiment of the present invention will be described below. The method of processing the reflective electrode wiring and connection electrodes is the same as in the first embodiment. The connection electrode is formed of a thin film of Cr or T,
When the gold B thin film is made of A2, when the connecting electrode is irradiated with laser light, the connecting electrode is first heated, vaporizes, expands, and peels off. Next, A2 melts, but Affi has a relatively large difference in melting point and boiling point. Therefore, while remaining in a melted state, the insulating film 12 is blown off along with the peeled-off connection electrode, and the reflective electrode is cut.

By forming metal thin films with different boiling points on the connection electrode as described above, when heated by a laser, etc., the vaporization and melting states of the connection electrode and the metal thin film are different, and one remains in the molten state and becomes the reflective electrode. Connected. Therefore, good cutting can be performed. Particularly good connections can be obtained by using Al for the metal thin film.

A reflective active matrix array according to a third embodiment of the present invention will be described below. Figure 1O is the third embodiment of the present invention.
FIG. 2 is a plan view of a reflective active matrix array according to an embodiment of the present invention. In FIG. 10, 23 and 24 are processing positions. FIG. 11(a) is a sectional view taken along line FF' in FIG. 10, and FIG. 11(b) is a sectional view taken along line CG' in FIG. 10.

In the third embodiment, no reflective electrode is formed above the reflective electrode wiring and the gate terminal of the TPT. therefore,
When cutting the processing position 24 or the gate terminal by irradiating a laser beam or the like, even if a pinhole or the like occurs in the insulator film 12 at the cutting part, or if the laser power is incorrectly adjusted,
There is no risk that the terminal or wiring will short-circuit with the reflective electrode on the upper layer. Therefore, the adjustment of laser power does not require precision, and the problem of producing defective products during array repair is eliminated.

Note that FIG. 12 is an equivalent circuit diagram of a reflective active matrix array in a third embodiment of the present invention.

A reflective active matrix array according to a fourth embodiment of the present invention will be described below. FIG. 13 is a plan view of an active matrix array in a fourth embodiment of the present invention. 14(a) is a cross-sectional view taken along line HH" in FIG. 13, FIG. 14(b) is a cross-sectional view taken along line XX in FIG. 13, and FIG. 15 is a fourth embodiment of the present invention. 14 is an equivalent circuit diagram of an example reflective active matrix array. In FIG. 13, FIG. 14(a), (b), and FIG.
26 and 27 are irradiation positions, 25 is an insulating film formed on the source signal line, and the connection wiring 9a to 9d is formed so that it is not electrically connected to the source signal line.
As is clear from the figure, reflective electrodes are not formed on the upper layer of the source signal line and gate signal line, and even if they are formed, they are formed to be as few as possible. By forming a pinhole in the insulator film 12, the reflective electrode and the gate
It is possible to eliminate defects caused by direct connection to the source signal line and deterioration of display quality due to capacitive coupling between the signal line and the reflective electrode. Corrections can be made by processing the irradiation positions 26 and 27 in the same manner as in the previous embodiment.

In addition, in the embodiment of the present invention, the switching element is T
Although PT is used, the present invention is not limited to this, and two terminals such as a diode may also be used.

Effects of the Invention The reflective active matrix array of the present invention is configured such that one or more of the terminals of the switching element can be disconnected, and the lower layer of each reflective electrode is provided with the drain terminal of the switching element that drives the adjacent reflective electrode. A connection electrode is formed that is connected to the . Therefore, in the method of repairing a reflective actenoic matrix array according to the present invention, first, the terminal of the defective switching element is cut off, and the switching element is prevented from applying a signal to the reflective electrode. Next, the connection electrode formed under the reflective electrode is irradiated with a laser beam or the like to connect the connection electrode and the reflective electrode. By the above method, the reflective electrode to which the defective switching element was connected can be normally driven by the adjacent switching element. By using the above-described reflective active matrix array and its modification method, it is possible to save almost all the switching elements, and the yield of the array can be increased to nearly 100%. Therefore, the manufacturing cost of the reflective active matrix array can be significantly reduced. This means that - as the number of picture elements formed on an array increases, it will become possible to easily manufacture even tens of thousands of picture elements, which until now was impossible to produce even a single good quality product. Has a thick effect.

[Brief explanation of the drawing]

1 and 5 are plan views of a reflective active matrix array according to the first embodiment of the present invention, and FIG. 2(a)
, (b), FIG. 4 is a sectional view of FIG. 1, and FIG. 3. FIG. 6 is an equivalent circuit diagram of a reflective active matrix array in the first embodiment of the present invention, FIG. 7(a),
(b) is a cross-sectional view of FIG. 5, FIG. 8 is a plan view of a reflective active matrix array according to the second embodiment of the present invention, FIG. 9 is a cross-sectional view of FIG. 8, and FIG. 10 is a cross-sectional view of the present invention. the third
11(a) and 11(b) are cross-sectional views of FIG. 10, and FIG. 12 is a plan view of the reflective active matrix array in the third embodiment of the present invention. The equivalent circuit diagram, FIG. 13 is a plan view of a reflective matrix array according to the fourth embodiment of the present invention, FIGS. 14(a) and (b) are sectional views of FIG. 13, and FIG. An equivalent circuit diagram of a reflective matrix array in the fourth embodiment, FIG. 16 is a plan view of a conventional reflective active matrix array, FIG. 17 (a), ■) is a cross-sectional view of FIG. 16, and FIG. 18 is an equivalent circuit diagram of a conventional reflective active matrix array, the first
FIG. 9 is a sectional view of a type liquid crystal display device. 1a~IC...source signal line, 2a~2C...
...Gate signal line, 3a-3d...Source terminal, 4a-4d...Gate terminal, 5a-5d
......Drain terminal, 6a-6d...Reflecting electrode wiring, 7a-7d...Contact hole, 8a-8r...Reflecting electrode, 9a-9d.・・・
...Connection wiring, 10a to 10d...Connection electrode, 11...Insulating substrate, 12...Insulator film, 13, 13 a 13 b---... -TFT,
14-source signal line, 15... gate signal line, 16... connection wiring, 17... reflective electrode, 1st... connection electrode, 19. ...Trajectory of rays, 20, 21, 22, 23, 24° 26.27
．． ...Irradiation position, 22a to 22d...
Metal thin film, 25...Insulator film, 01~G4...
...Gate signal line, S1-S8...Source signal line, TII-T 4ff...T F T
, P 11 "" P 43...Reflecting electrode, 2
7゜29・・・Alignment film, 28・・・Liquid crystal,
30...Transparent electrode, 31...Counter electrode. Name of agent Patent attorney Toshio Nakao 1 person 1/-11 father-in-law 14 prongs (b) 13- FT 14-- source 3, line 15- 1E Yue Haiju 17- and dark blue electric attack figure 3 /δ- 撞HA Takune figure 6 figure 7? 3.24 --- Pier Hayao Cry! Fig. 10 Fig. 11 Fig. 12 Fig. 26.27 --- Irradiation position (α) Fig. 15 Fig. 16' iy haΣ
l~δ,? -Zone Store No.18 Figure 7'/1~ -7FTP
t+～～−11 emissive electric name

Claims (9)

[Claims] (1) A reflective active matrix array,
The first terminal connects one terminal of the switching element and the reflective electrode.
a connection electrode formed below the reflective electrode adjacent to the reflective electrode via an insulating film, and a second wiring that electrically connects the first wiring and the connection electrode. A reflective active matrix array comprising: (2) The reflective active matrix array according to claim (1), wherein the connection electrode is made of metal, and a metal thin film having a boiling point different from that of the metal of the connection electrode is formed on the connection electrode. (3) The switching element is a two-terminal element or a three-terminal element, and includes a cutting portion that can electrically disconnect at least one terminal among the terminals of the element from the reflective electrode or the signal line. 1) The reflective matrix array described above. (4) The reflection according to claim (3), wherein the connection electrode or the thickness of the connection electrode plus the metal thin film formed on the electrode is formed thicker than the thickness of the cutting portion. type active matrix array. (5) The reflective active matrix array according to claim (3), wherein no reflective electrode is formed on at least one cutting site. (6) Cut the terminal of the switching element or the first wiring using at least one of optical and thermal processing means so that no signal is applied to the reflective electrode from the switching element; and electrically connecting the second wiring and the reflective electrode by dissolving or vaporizing a constituent material of the connection electrode formed in the lower layer of the reflective electrode that was connected to the first wiring. A method for modifying reflective active matrix arrays. (7) The method for repairing a reflective active matrix array according to claim (6), wherein the processing means is one that condenses light from a laser or a xenon lamp. (8) The method for repairing a reflective active matrix array according to claim (6), wherein the processing means passes through the substrate on which the active matrix array is formed and processes the cutting portion or the connection electrode. (9) The reflective type according to claim (6), characterized in that a plurality of pulses of laser or focused light from a xenon lamp is applied to the cutting portion, and one or more pulses of the light is applied to the connection electrode. How to modify a matrix array.