JPH02256028A - Active matrix substrate - Google Patents

Abstract

PURPOSE:To prevent the breakdown of insulating films by static electricity by connecting at least >=2 pieces of the signal lines of switching elements with a 1st metallic film at the signal line end and incorporating the 2nd metallic film formed on the outer side of the signal line end in such a manner that the patterns thereof overlap partly on the 1st metallic film via the insulating film. CONSTITUTION:The 1st insulating film 5 is formed on the metallic film patterns 3 simultaneously with the formation of the switching elements. Common electrode patterns 4 are in succession formed on the 1st insulating film 5 and the 2nd insulating film 6 is formed thereon. Finally, the metallic film 7 is so formed as to overlap on the patterns 3 simultaneously with the formation of the metallic film 11 to be formed as the reinforcing film for the signal lines. All the signal lines 2 are, therefore, eventually capacity-coupled to the patterns 4 via the 1st insulating film 5 and the 2nd insulating film 6 and the capacity between the signal lines over the entire part of the active matrix substrate is increased. The voltages to be impressed to the intersected parts of the signal lines are lowered in this way even if the high voltage is impressed to the signal lines by the static electricity. The breakdown of the insulating films by the static electricity is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an active matrix substrate used in a liquid crystal display panel.

BACKGROUND OF THE INVENTION In recent years, with the miniaturization of industrial equipment, there has been a demand for thin flat display devices to replace conventional display devices.Among the various flat display devices, display devices using liquid crystals consume less power. It is attracting attention because it is easy to display in full color. In particular, active matrix liquid crystal display panels in which each display pixel is provided with a switching element have excellent display image quality and are therefore being applied to portable televisions and the like.

FIG. 4 is an equivalent circuit diagram showing the structure of a conventional active matrix substrate. In FIG. 4, 51 is a thin transistor, 52 is a metal film pattern for shorting the signal line, and X1-X.

is a scanning signal line, and yt-"n is a video signal line.

However, active matrix substrates have the problem that static electricity that builds up on the substrate during the manufacturing process destroys the insulation film at the intersections of switching elements and scanning signal lines and video signal lines, resulting in short-circuit defects. Ta. As a measure to prevent damage to the insulating film due to static electricity,
Conventionally, as shown in FIG. 4, a method has been used in which all terminals of an active matrix substrate are short-circuited with a metal film pattern 52, and after assembly into a liquid crystal panel, this metal film pattern 52 is cut.

Problems to be Solved by the Invention However, in the conventional method for preventing breakdown of an insulating film due to static electricity as shown in Fig. 4, all terminals are shattered, so it is necessary to cut off shorted parts after the active matrix substrate is completed. Until now, it was not possible to inspect short-circuit defects such as disconnection defects due to signal line disconnections, short-circuit defects between adjacent scanning signal lines or video signal lines, and short-circuits between scanning signal lines and video signal lines.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an active matrix substrate that prevents breakdown of an insulating film due to static electricity and allows defect inspection.

Means for Solving the Problems In order to solve the above problems, the present invention connects at least two signal lines of switching elements of an active matrix substrate with a first metal film formed on a glass substrate at the ends of the signal lines. However, a part of the pattern of the second metal film formed outside the end of the signal line overlaps with the first metal film via the first and second insulating films.

Effect: With the above-described configuration, the present invention prevents breakdown of the insulating film due to static electricity on the active matrix substrate, and also makes it possible to inspect signal line disconnections and short circuit defects between the scanning signal line group and the video signal line group. shall be.

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

FIG. 1 is a configuration diagram of an active matrix substrate in one embodiment of the present invention. In Fig. 1, l is a thin film transistor, 2 is an input terminal for the scanning signal line and the video signal line, 3 is a metal pattern for shorting the scanning signal line and the video signal line, and 4 is a common electrode on the outside of the input terminal for the signal line. 5 and 6 are the first insulating film and the second insulating film, respectively, X1 to X, n are scanning signal lines, and Y1 to Yn are video signal lines. As shown in FIG. 1, every other scanning signal line and video signal line is connected to a metal film pattern 3, and is connected to a common electrode pattern 4 via an insulating film.

Figure 2 shows metal film pattern 3 and common electrode metal film pattern 4.
1, and FIG. 3 is a schematic sectional view taken along the line a-a' in FIG. 2. FIG. The structure of this embodiment will be explained with reference to FIGS. 2 and 3. When forming the input terminal 2 of the signal line on the glass substrate 10, a metal film pattern 3 for shorting the signal line is also formed at the same time. Next, when forming the switching elements, the first insulating film 5 is formed on the metal film pattern 3 at the same time. Subsequently, a common electrode pattern 4 is formed on the first insulating film 5, and a second insulating film 6 is formed thereon. Finally, the metal film 7 is formed so as to overlap the metal film pattern 3 at the same time as the metal film 11 serving as a reinforcing film for the signal line is formed. This metal film 7
It is connected to the common electrode pattern 4 through a contact hole 8 formed in the insulating film 6.

With this configuration, all the signal lines 2 are capacitively coupled to the common electrode pattern 4 via the first insulating film 5 and the second insulating film 6, and the signal lines of the entire active matrix substrate are The capacity between can be increased. Therefore, even if a high voltage of several hundred to several kilovolts is applied to the signal line due to static electricity, the voltage applied to the intersection of the signal lines can be lowered, and breakdown of the insulating film due to static electricity can be prevented. Further, the insulating film between the metal film pattern 3 and the metal film 7 for configuring capacitive coupling between the signal line 2 and the common electrode pattern 4 has a two-layer structure of a first insulating film 5 and a second insulating film 6. By doing so, it is possible to prevent short circuit between the signal line 2 and the common electrode pattern 4 due to pinholes generated in the insulating film.

Next, a defect inspection method according to this embodiment will be explained. To test for disconnection of the signal line, since the terminals on one side of both the scanning signal line and the video signal line are not connected, the inspection can be performed by connecting the metal film pattern 3 and the input terminal 210-b needle and measuring the resistance value. I can do it.

Inspection for short-circuit defects between adjacent signal lines is possible because every other signal line is connected to the metal film pattern 3.
By connecting a probe needle to pattern 3 and measuring the resistance value, short defect inspection can be performed on the two blocks. In addition, short-circuit defect inspection between the scanning signal line and the video signal line is possible because each metal film pattern 3 is electrically insulated by the first insulating film 5 and the second insulating film 6. By connecting probe needles to the metal film pattern on the side and the metal film pattern on the video signal line side, and measuring the resistance value, short-circuit defect inspection can be performed on the block.

The reinforcing metal film 11 is not formed on the connecting portion between the signal line and the metal film pattern 3, which is shown in part b in FIG. 2, so that it can be easily cut with a laser beam or the like after the inspection is completed.

Effects of the Invention As described above, the present invention connects at least two signal lines of switching elements of an active matrix substrate with a first metal film formed on a glass substrate at the ends of the signal lines, and A part of the pattern of the second metal film formed on the outside of the second metal film is configured to overlap with the first metal film via the first and second insulating films, thereby protecting the insulation film from breakdown due to static electricity. The present invention has an excellent effect in that it is possible to perform open circuit defect inspection and short circuit defect inspection of scanning signal lines and video signal lines.

[Brief explanation of drawings]

Figure 1 shows the active multilayer l-I in one embodiment of the present invention.
A structural diagram of the J-Fuchs board, Fig. 2 is a structural diagram of section A in Fig. 1, Fig. 3 is a schematic sectional view taken along section a-a' in Fig. 2, Fig. 4
The figure is a configuration diagram showing the configuration of a conventional active matrix substrate. 1... Thin film transistor, 2... Input terminal, 3... Metal film pattern, 4...
Common electrode pattern, 5...first insulating film, 6.
...Second insulating film, X. ~X,...Scanning signal line, Y1~Yn...
・Video signal line. Name of agent: Patent attorney Shigetaka Awano 1 person f-X seconds ■ J register 2, - input 1 * Aq 3 - J register 4 and η F ° Darn Y + v Yn --- "I1 Itt thousand & (deviate) bride size

Claims (4)

[Claims] (1) An active matrix substrate in which switching elements are arranged in a matrix on a glass substrate, wherein a first metal film is formed on the glass substrate at least two or more signal line ends of the signal lines of the switching elements. A part of the pattern of the second metal film formed outside the end of the signal line is overlapped with the first metal film via the first and second insulating films. Active matrix substrate. (2) The pattern of the second metal film formed outside the input terminal of the signal line is formed between the first insulating film and the second insulating film. Active matrix substrate. (3) The active according to claim (1), wherein the pattern of the second metal film formed outside the input terminal of the signal line is sufficiently thicker than the pattern width of the signal line to serve as a common electrode. matrix substrate. (4) The active matrix substrate according to claim (1), wherein the switching element is composed of a two-terminal element or a thin film transistor.