JPS58178321A - Electrooptic device - Google Patents

Abstract

PURPOSE:To relieve the spot defect of a display owing to a defective switching element by connecting one switching element to an electrode for displaying each of many picture elements, providing a spare element which is not connected to the electrode. CONSTITUTION:A switching element 11 of the two elements 11, 12 provided to a data wire 10 is connected by means of a wiring 13 to an electrode 14 for displaying each of many picture elements. If the element 11 is defective, the wiring 13 is cut and the spare element 12 is connected to the electrode 14 by means of a wiring 15. The picture element 14 which is the spot defect of a display is thus relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electro-optical device in which picture elements each having a switching element are arranged in a matrix. In recent years, liquid crystal display devices have been put into practical use and are being applied to many fields including wristwatches and calculators. However, when considering applications in other fields, such as display units in information terminals and small personal electronic devices, despite the advantages of display units such as small volume, low voltage drive, and low power consumption, However, since the driving voltage-contrast characteristics are not very good and multi-digit matrix driving is not possible, the amount of information that can be displayed is small.

As a method to eliminate the drawbacks of liquid crystal display devices, matrix driving using switching elements can be considered, especially MOS) transistors, thin film transistors,
Research and development of matrix displays incorporating elements is actively being conducted.

These switching elements are arranged in a matrix on the same substrate, and each switching element drives a respective picture element. Therefore, since a picture element with a defective switching element becomes a point defect, all of these switching elements must be non-defective.

However, it is currently unavoidable to introduce some defects during the manufacturing process of switching elements, and it is difficult to produce display devices without point defects. Here, a liquid crystal display device equipped with a nonlinear element having an MUM structure will be taken as an example. The basic structure of the M element is as shown in Figs. 1 and 2, in which a glass substrate 1 is coated with a TagoB film 2.
After sputtering a Ta thin film or a nitrogen-doped Ta thin film 3, it is patterned into a predetermined shape and the surface is anodized to form an oxide film 4. Further, M i -Or and Au thin films are deposited and patterned to form the counter electrode 5 .

Ni −
Transparent electrodes 6 of Or and Au are attached. In order to make a display device, the transparent electrodes 6 are arranged in a matrix as shown in FIG. 3 to form one picture element, and the lead portions 7 in FIG.
A TN panel is made by sealing liquid crystal between the substrate and a counter substrate having a plurality of striped transparent electrodes perpendicular to the substrate.

When a voltage is applied between both ends of the M element, that is, between the TaN film or nitrogen-doped Ta thin film 3 and the opposing electrode 5 of the Hi Or/Au thin film, a non-linear voltage - voltage is generated as shown in Fig. 4. The current characteristics are obtained and the relationship is: X=KVexp (β,/'T) (1) [
where β is a coefficient] This applies to the equation representing the Poole-Franker effect.

When dynamically driving the TM panel that combines this Y-factor M element and liquid crystal, the effective value ratio of the ON voltage and OFF voltage actually applied to the liquid crystal increases due to the nonlinearity of the M-factor element, and Multi-digit dynamic driving is possible, and dynamic driving of 1/100 to 1/200 duty can be easily achieved.

Although the M-engineered M-element has a very simple structure and a simple manufacturing method, the introduction of defects cannot be avoided. The main causes of defects are: 1. Defects caused by photo-etching 2. Defects in the T& film (pinholes, etc.) Defects in the pentaanodic film (pinholes, poor film quality) 4. Defects caused by dust and dirt, etc. There is.

Although the above defects can be reduced, it is considered impossible to completely eliminate them.

Therefore, in order to apply M technology and M element to display devices,
Defects require redress.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electro-optical device that can repair point defects in a display device caused by defective switching elements.

In the present invention, the display section of an electro-optical device is composed of a large number of picture elements, and each picture element has at least one switching element connected to an electrode for display, and also has a switching element not connected to the electrode. However, if the switching element connected to the electrode is defective, disconnect the defective switching element from the electrode, or disconnect the data line from the switching element, and replace the switching element not connected to the electrode (hereinafter referred to as a spare element). The defective picture element is repaired by connecting it to the electrode.

FIG. 5 shows an outline of the present invention. FIG. 5(a) is a schematic diagram showing a 1f& element of an electro-optical device according to the present invention, in which two switching elements are connected to a data line 10, one element 11 is connected to an electrode 14 by a wiring 13, The other element 12 is not connected to the electrode 14 as a spare element. If the element 11 is found to be defective by the electrical characteristic test or display test of the element 11, the element 11 and the electrode 14 are arranged as shown in FIG. 5Cb'). 13, and furthermore, the spare element 12 is metal-plated IIj! It is connected to the electrode 14 at 15. With the above, it is possible to repair picture elements that become point defects.f! Ru. tJ6VACC) is 1 child 11 Tochita +1
110 is disconnected.

The wiring can be cut by irradiating the wiring with a focused laser beam to partially evaporate the wiring. Another cutting method is to apply a positive type 7 photoresist on the substrate, irradiate the area to be cut with a focused ultraviolet laser to expose the resist, and develop it to remove the resist at the designated area. After that, cutting can be performed using a normal photoetching method.

In addition, the connection is made by setting the metal film formed on the glass at the predetermined position to be connected, either in contact or with a gap of several μm, and by irradiating the metal film with a focused laser from above the glass, the metal is evaporated. By vapor depositing metal at predetermined positions, it becomes possible to connect the predetermined positions. Another method is to further form a metal film on the substrate and use a negative type 7
Apply photoresist, expose the resist by irradiating it with concentrated ultraviolet rays at the predetermined locations to be connected, develop it, leave the resist in the predetermined locations, and remove the rest.After that, the metal is etched using the normal photoetching method. Connection is now possible.

<Example> FIG. 6 shows an example of an electro-optical device in which an MIM element, which is a non-IIl type element, is applied to a liquid crystal display device.

The M element 21 is connected to the data 112o, and the M element 21 is further connected to the electrode 23. Also, one spare M element 22 is incorporated for every two picture elements, and the spare M element 22 is connected to a common data line with other M elements 21. On the other hand, electrode 2
3 (Fig. 6 (α)). With the above structure, if one of the M elements 21 connected to a picture element is defective, the spare element can be used to prevent it from becoming a defective picture element. This modification is shown in Figure 6 Ch). First, the connection between the defective element 21 and the data line is cut using a laser beam.

24... Cutting part. The connection between the electrode 23 and the element 21 may be cut. Next, the preliminary element 22 and the electrode 23 are connected. For this connection, a glass on which a metal film such as Au is formed is placed on a substrate on which an M element is formed, and a focused laser beam is irradiated onto the metal film to locally evaporate the metal. This can be done by vapor deposition on the substrate on the M element side. FIG. 7 is a schematic diagram showing a connection method using laser light, and FIG. 7 (α) shows the glass substrate 31 on which the metal film 33 is formed is set on the element substrate 32, and #! Figure 7(b) shows conductor 34 and conductor 3 by vaporizing metal by laser beam irradiation.
This shows where the connections in step 5 were made. 36...Deposited metal, 37...Laser light.

As described above, the present invention makes it possible to correct defective picture elements that could not be avoided in the past, thereby improving the yield of electro-optical devices.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are a cross-sectional view and a plan view showing the structure of a conventional M element. FIG. 3 shows part of a display device equipped with a conventional MIM element. FIG. 4 shows the voltage-current characteristics of the V-type M element. FIGS. 5(α), (h), and (c) are introductory diagrams of the display device according to the present invention. FIG. 6(α')t() shows an application of the present invention to a display device equipped with an M element. FIG. 7(α)I Cb) is a sectional view showing a method of conductive connection. Applicant Suwa Seikosha Co., Ltd. Figure 1 Figure 3 Figure 14 Figure 6

Claims (1)

[Claims] 1. In an electro-optical device in which picture elements are arranged in a matrix and at least one switching element for each picture element is connected to an electrode constituting each picture element, The switching element that is not connected to the electrode that
An electro-optical device characterized in that at least one electro-optical device is provided for one picture element. λ In an electro-optical device in which picture elements are arranged in a matrix and at least one switching element for each picture element is connected to the electrodes that make up each picture element, it is not connected to the electrodes that make up the picture element. The switching element is 2
An electro-optical device characterized in that one electro-optical device is provided for each picture element.