JP3179319B2 - Defect detection method for matrix type display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect detection method for a matrix type display device for detecting a short circuit between signal lines via a spare line used in an active matrix type liquid crystal display device. .

[0002]

2. Description of the Related Art In recent years, as information devices have become smaller, lighter, and more sophisticated, flat display devices such as liquid crystal display devices have become widespread. Such display devices include a VGA (Video Graphics Array) and an S-VGA (Super
-Video Graphics Array), XGA (Extended Graphics A)
(rray) etc. are required. However,
A display device having a high resolution has a large number of picture elements and a large number of electrodes. For this reason, the display device includes
A matrix display device in which picture elements are provided in a matrix is used.

However, in the matrix type display device, the scanning lines and signal lines formed on the substrate have been reduced in line width as the resolution of the display device has been increased, and the display size has been increased due to the enlargement of the screen. The length of routing on the device is increasing. For this reason, the scanning lines and the signal lines are liable to cause disconnection defects in the production process. When a disconnection failure occurs in a scanning line or a signal line, it is impossible to display and drive the picture elements beyond the disconnection failure portion, and the display quality is remarkably deteriorated.

Therefore, Japanese Patent Laid-Open Publication No. 3-23425 proposes a configuration of a liquid crystal display device which can be repaired even if the disconnection failure occurs. Such a general liquid crystal display device 1 will be described with reference to FIGS. FIG.
1 is a schematic equivalent circuit diagram showing the liquid crystal display device 1. FIG. FIG. 5 is an enlarged plan view showing a main part of the liquid crystal display device 1 when the spare lines 14a and 14b and the signal line 5 are short-circuited via the defective part 19.

Referring to FIG. 4, the liquid crystal display device 1 includes a panel 2 as a display unit, a scanning signal driving unit 3 for applying a video signal, and a display signal driving unit 4.
The panel 2 includes, for example, a pair of upper and lower mutually parallel glass substrates, a polarizing plate formed on the outer surface of both glass substrates, and a transparent electrode formed on the inner surface of each glass substrate, An alignment film formed on the transparent electrode, a sealing resin for hermetically sealing the outer peripheral portions of both glass substrates, and a liquid crystal material sealed in a space formed by the glass substrate and the sealing resin. I have. The transparent electrodes are formed, for example, in common on the upper substrate, whereas on the lower substrate, they are arranged in a matrix corresponding to each picture element.

[0006] On the upper substrate, a number of signal lines 5 parallel to one direction and a number of scanning lines 6 are provided in parallel to the signal lines 5 in parallel. The signal line 5 and the scanning line 6 intersect while being electrically insulated. Pixel electrodes 7 are provided in respective regions surrounded by the signal lines 5 and the scanning lines 6. A TFT (Thin Film Transistor) 8 is connected to the picture element electrode 7 as a switching element. The gate electrode 9 of the TFT 8 is connected to the scanning line 6, the source electrode 10 is connected to the signal line 5, and the drain electrode 11 is connected to the auxiliary capacitance 12 and the corresponding picture element electrode 7. The auxiliary capacitance 12 is disposed on the common line 13 via the insulating film 16 shown in FIG. The common lines 13 cross each scanning line 6 in parallel with the signal lines 5 while being electrically insulated from each other.
Are all short-circuited, and via the common line terminal 13a,
It is connected to the lower substrate.

The TFT 8 is turned on when selected by a selection pulse applied to the scanning line 6, and charges the liquid crystal and the auxiliary capacitor 12 with a gradation voltage corresponding to a duty pulse applied to the signal line 5. The liquid crystal and the auxiliary capacitor 12 hold the charge until the next scanning timing, and an image is displayed.

The signal line 5 is connected to the display signal drive unit 4 via a signal line terminal 5a, and a display signal is applied. On the other hand, the scanning line 6 is connected to the scanning signal drive unit 3 via the scanning line terminal 6a, and a scanning signal is applied.

On one end of the panel 2, the signal lines 5 are perpendicular to the signal lines 5, that is, parallel to the scanning lines 6.
And auxiliary wirings 14a and 14b which are electrically insulated via an insulating film 16 shown in FIG. The spare wires 14a and 14b are connected via a spare wire terminal 15 by a communication line (not shown).

In the above configuration, for example, when the occurrence of a disconnection failure as indicated by reference numeral 17 is detected in the signal line 5 in an inspection step or the like, the signal line 5 and the spare line 14a are detected.
18a and the intersection 18b between the signal line 5 and the spare wiring 14b are formed by the laser light irradiation.
Is electrically connected by removal of the above.

As a result, a drive voltage is directly applied to the TFT 8 from the disconnection defective portion 17 toward the display signal drive unit 4 via the signal line 5. On the other hand, disconnection defect location 1
The TFTs 8 beyond 7 are connected to the signal line 5 on the display signal drive unit 4 side to the spare line 14a, the connection line,
b, and a drive voltage is applied via the signal line 5 on the far side from the disconnection failure portion 17. That is, the disconnection defective portion 17 is bypassed, and the picture elements before and after the defective location can both be displayed as images.

However, as shown in FIG. 5, a defective portion 19 occurs at the intersection of the signal line 5 and the spare wiring 14a, 14b due to a film formation defect of the insulating film 16, and the signal line 5 and the spare wiring 14a・ 14b may be short-circuited.
A plurality of defective portions 19 are generated, and the signal lines 5 for driving picture elements corresponding to different color filters are connected to the spare wiring 1.
In the case of short-circuiting via the signal lines 4a and 14b, for example, as shown in FIG. 6, when the adjacent signal lines 5 (n) and 5 (n + 1) are short-circuited, or in FIG. As shown, the signal line 5 (n) and the signal line 5 (m × (n +
1)) or when at least one of the signal lines 5 (m × (n + 2)) is short-circuited via the spare wirings 14a and 14b, the signals applied to the short-circuited signal lines 5 have the same level. For this reason, the signal lines 5 (n),
In 5 (n + 1); 5 (n), 5 (m × (n + 1)), a line defect is generated. In a typical conventional technique, the line defect is caused by a solid screen shown in FIG. This is detected by displaying the horizontal gradation screen shown in FIG.

[0013]

However, when the signal lines 5 for driving picture elements corresponding to the same color filter are short-circuited via the spare wires 14a and 14b, for example, as shown in FIG. Line 5 (n) and signal line 5 (m
× n), the above-mentioned line defect occurs even when short-circuiting occurs. However, this line defect has a problem that it cannot be detected by the solid screen or the horizontal gradation screen described above with reference to FIGS. 8A and 8B.

It is an object of the present invention that the signal lines 5 for driving picture elements corresponding to color filters of different colors are connected to the auxiliary wiring 14.
It is possible to detect line defects that occur not only when the signal lines are short-circuited via the a and 14b but also when the signal lines 5 for driving the picture elements corresponding to the same color filter are short-circuited via the spare lines 14a and 14b. It is an object of the present invention to provide a defect detection method for a matrix type display device.

[0015]

In order to solve the above-mentioned problems, a method for detecting a defect in a matrix type display device according to the present invention comprises a plurality of scanning lines arranged in parallel with each other on a substrate. A plurality of signal lines which are electrically insulated from the scanning lines and are orthogonally arranged are formed, and are connected to both ends when the scanning lines or the signal lines are disconnected to form spare wirings for bypassing the disconnected portions. In the defect detection method of the matrix type display device described above, display driving is performed by a signal whose luminance level switches at different timings in each horizontal scanning cycle.

According to the above method, each horizontal scanning is performed to check whether or not the plurality of scanning lines or the plurality of signal lines are conducting through the spare wiring due to an undesired short circuit. In each cycle, a signal whose luminance level switches at a different timing is applied to the matrix type display device. Thereby, if there is the short circuit, the signal lines or the scanning lines which are conducting are simultaneously exposed.

As a result, not only is the signal line for driving the picture element corresponding to the color filter of a different color short-circuited through the spare wiring, but also the signal line for driving the picture element corresponding to the color filter of the same color. Since a line defect generated when the two are short-circuited via the spare line can be detected, the quality and reliability of the matrix display device can be improved.

According to a second aspect of the present invention, there is provided a defect detection method for a matrix type display device, wherein a plurality of scanning lines arranged in parallel with each other on a substrate and a plurality of orthogonally arranged are electrically insulated from the scanning lines. In the defect detection method for a matrix-type display device, a signal line is formed and connected to both ends of the scanning line or the signal line when the signal line is disconnected, and a spare line for bypassing the disconnected portion is formed. switched timing of the luminance level in the horizontal scanning period mutually corresponding in is characterized by performing the display driving by mutually different signals between each frame.

According to the above-described method , a phase is determined between frames to check whether or not the plurality of scanning lines or the plurality of signal lines are conducting through the spare wiring due to an undesired short circuit. Signals having different luminance level switching timings in the corresponding horizontal scanning periods between the respective frames are applied to the matrix display device. Thereby, if there is the short circuit, the signal lines or the scanning lines which are conducting are simultaneously exposed.

As a result, the signal lines for driving the picture elements corresponding to the color filters of the same color are not only short-circuited with each other through the spare wiring but also driving the picture elements corresponding to the color filters of the different colors. Since a line defect generated when the two are short-circuited via the spare line can be detected, the quality and reliability of the matrix display device can be improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The defect detection method for a matrix type display device of the present invention is used for the general liquid crystal display device 1 shown in FIGS. FIG. 4 is a schematic equivalent circuit diagram showing the liquid crystal display device 1. FIG.
FIG. 3 is an enlarged plan view showing a main part of the liquid crystal display device 1 when the spare lines 14 a and 14 b and the signal line 5 are short-circuited via the defective part 19.

As shown in FIG. 4, the liquid crystal display 1
Is composed of a panel 2 as a display unit, a scanning signal driving unit 3 for applying a video signal, and a display signal driving unit 4. The panel 2 includes, for example, a pair of upper and lower mutually parallel glass substrates, a polarizing plate formed on the outer surface of both glass substrates, and a transparent electrode formed on the inner surface of each glass substrate, An alignment film formed on the transparent electrode, a sealing resin for hermetically sealing the outer peripheral portions of both glass substrates, and a liquid crystal material sealed in a space formed by the glass substrate and the sealing resin. I have. The transparent electrodes are formed, for example, in common on the upper substrate, whereas on the lower substrate, they are arranged in a matrix corresponding to each picture element.

On the upper substrate, a number of signal lines 5 parallel to one direction and a number of scanning lines 6 are provided in parallel at right angles to the signal lines 5. The signal line 5 and the scanning line 6 intersect while being electrically insulated. Pixel electrodes 7 are provided in respective regions surrounded by the signal lines 5 and the scanning lines 6. A TFT (Thin Film Transistor) 8 is connected to the picture element electrode 7 as a switching element. The gate electrode 9 of the TFT 8 is connected to the scanning line 6, the source electrode 10 is connected to the signal line 5, and the drain electrode 11 is connected to the auxiliary capacitance 12 and the corresponding picture element electrode 7. The auxiliary capacitance 12 is disposed on the common line 13 via the insulating film 16 shown in FIG. The common line 13 intersects with the scanning lines 6 in parallel and is electrically insulated from the signal lines 5. The common lines 13 are all short-circuited, and are connected to the lower substrate via common line terminals 13a.

The TFT 8 is turned on when selected by a selection pulse applied to the scanning line 6, and charges the liquid crystal and the auxiliary capacitance 12 with a gradation voltage corresponding to the duty pulse applied to the signal line 5. The liquid crystal and the auxiliary capacitor 12 hold the charge until the next scanning timing, and an image is displayed.

The signal line 5 is connected to the display signal driver 4 via a signal line terminal 5a, and a display signal is applied. On the other hand, the scanning line 6 is connected to the scanning signal drive unit 3 via the scanning line terminal 6a, and a scanning signal is applied.

On one end of the panel 2, the signal lines 5 are perpendicular to the signal lines 5, that is, parallel to the scanning lines 6.
And auxiliary wirings 14a and 14b which are electrically insulated via an insulating film 16 shown in FIG. The spare wires 14a and 14b are connected via a spare wire terminal 15 by a communication line (not shown).

In the liquid crystal display device 1 having the above configuration, an inspection signal, which will be described later, is applied in order to detect a short circuit between the signal lines 5 via the spare wires 14a and 14b.
The inspection signal is a signal in which the luminance level switches at different timings in each horizontal scanning cycle, that is, the image signal changes in units of five signal lines at one horizontal synchronization timing of each scanning signal in one field. It is the signal that was made. With this inspection signal, for example, an oblique solid screen shown in FIG. 2A or an oblique gradation screen shown in FIG. 2B is displayed.

When detecting a short circuit between signal lines 5 for driving picture elements corresponding to color filters of the same color via the spare wires 14a and 14b, for example, as shown in FIG.
A case where a short circuit between the signal line 5 (n) and the signal line 5 (m × n) is detected will be described. In FIG. 1, signal line 5
When the inspection signal for displaying the diagonally solid screen shown in FIG. 2A is applied to the liquid crystal display device 1 in which (n) and the signal line 5 (m × n) are short-circuited, An area as shown by in the figure becomes apparent. This area includes signal line 5
(N) corresponds to the driven picture elements P (n, 1) to P (n, i). However, originally, the signal line 5 (n)
Since only signals for driving the picture element P (n, 1) and the picture element P (n, 2) are input to the picture element P (n, 3) and the picture element P (n, i), Are not driven. On the other hand, signal line 5
A signal for driving the picture elements from the picture element P (m × n, 1) to the picture element P (m × n, i) is input to (m × n). This indicates that the signal line 5 (n) and the signal line 5 (m × n) are short-circuited. Then, the short-circuited signal line 5
(N) can be corrected by laser light irradiation or the like.

Further, the liquid crystal display device 1 in which the signal lines 5 for driving the picture elements corresponding to the different color filters are short-circuited through the auxiliary wirings 14a and 14b, as shown in FIG.
Even if the inspection signal for displaying the diagonally solid screen shown in (a) is applied, the short-circuited signal line 5 can be detected.

As another inspection signal, a signal having a different luminance level switching timing in a corresponding horizontal scanning period between frames, that is, 1
There is a signal for moving the isolated pattern every frame. With this inspection signal, for example, an isolated pattern horizontal movement screen shown in FIG. 3 is displayed.

The signal lines 5 for driving the picture elements corresponding to the color filters of the same color are connected to the spare lines 14 by the inspection signal.
The signal line 5 that is short-circuited can be detected by applying the voltage to the liquid crystal display device 1 that is short-circuited via a and 14b. The short-circuited signal line 5 can be corrected by laser light irradiation or the like.

Further, the signal lines 5 for driving picture elements corresponding to the different color filters are connected to the spare lines 14a and 14a.
Even if the inspection signal for displaying the isolated pattern horizontal movement screen shown in FIG. 3 is applied to the liquid crystal display device 1 which is short-circuited via the line b, the short-circuited signal line 5 can be detected.

As described above, in the liquid crystal display device 1, the luminance level is switched at different timings in each horizontal scanning cycle or the luminance level switching in the corresponding horizontal scanning cycle is performed between frames. If signals having different switching timings are applied, the spare wiring 14a
Any short circuit between the signal lines 5 via 14b can be detected. As a result, the quality and reliability of the liquid crystal display device 1 can be improved.

[0034]

As described above, the defect detection method for a matrix type display device according to the first aspect of the present invention provides a plurality of scanning lines arranged in parallel with each other on a substrate and electrically insulated from the scanning lines. A plurality of signal lines arranged orthogonally to each other, and connected to both ends of the scanning line or the signal line when a disconnection occurs, to form a spare line for bypassing the disconnection point. The detection method is characterized in that display driving is performed by a signal whose luminance level switches at different timings in each horizontal scanning cycle.

Thus, not only are signal lines for driving picture elements corresponding to color filters of different colors short-circuited through spare wiring, but also signal lines for driving picture elements corresponding to color filters of the same color. Since a line defect that occurs when the elements are short-circuited via the spare line can be detected, the quality and reliability of the matrix display device can be improved.

According to a second aspect of the present invention, there is provided a defect detection method for a matrix type display device, wherein a plurality of scanning lines are arranged on a substrate in parallel with each other and the scanning lines are electrically insulated from each other and are orthogonally arranged. In the defect detection method for a matrix type display device, a plurality of signal lines are formed and connected to both ends of the scanning line or the signal line when the line is disconnected, and a spare line for bypassing the disconnected part is formed. switched timing of the brightness levels in the mutually corresponding horizontal scanning period phase between frames is characterized by performing the display driving by mutually different signals between each frame.

Thus, not only are the signal lines for driving picture elements corresponding to the color filters of different colors short-circuited through the spare wiring, but also the signal lines for driving picture elements corresponding to the color filters of the same color. Since a line defect that occurs when the elements are short-circuited via the spare line can be detected, the quality and reliability of the matrix display device can be improved.

[Brief description of the drawings]

FIG. 1 shows a state when an oblique solid screen shown in FIG. 2A is displayed on a liquid crystal display device in which signal lines for driving picture elements corresponding to color filters of the same color are short-circuited via spare wiring. FIG.

FIG. 2 is a pattern diagram showing an example of an image displayed when a signal based on a defect detection method of the matrix display device of the present invention is applied, and FIG. 2A is a pattern diagram showing an oblique solid screen; FIG. 2B is a pattern diagram showing an oblique gradation screen.

FIG. 3 is a pattern diagram showing an isolated pattern horizontal movement screen which is another example displayed when a signal based on the defect detection method of the matrix display device of the present invention is applied.

FIG. 4 is a schematic equivalent circuit diagram showing a general liquid crystal display device provided with spare wiring.

FIG. 5 is an enlarged plan view showing a main part when a spare line and a signal line are short-circuited via a defective part in the liquid crystal display device shown in FIG.

FIG. 6 is an explanatory diagram showing a state when adjacent signal lines are short-circuited in the liquid crystal display device shown in FIG. 4;

FIG. 7 is an explanatory diagram showing a state where signal lines for driving picture elements corresponding to different color filters are short-circuited via spare wiring in the liquid crystal display device shown in FIG. 4;

FIG. 8 is a defect detection inspection pattern diagram for inspecting a short circuit between signal lines via a conventional spare line.

9 is an explanatory diagram showing a state in which signal lines for driving picture elements corresponding to color filters of the same color are short-circuited via spare wiring in the liquid crystal display device shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device (matrix type display device) 2 Panel (substrate) 3 Scan signal drive unit 4 Display signal drive unit 5 Signal line 6 Scan line 5a Signal line terminal 6a Scan line terminal 8 TFT 9 Gate electrode 10 Source electrode 11 Drain electrode DESCRIPTION OF SYMBOLS 12 Auxiliary capacitance 13 Common line 13a Common line terminal 14a Spare wiring 14b Spare wiring 15 Spare wiring terminal 16 Insulating film 17 Disconnection defective part (disconnection part) 18a Intersection 18b Intersection 19 Defect part

Claims (2)

(57) [Claims] 1. A plurality of scanning lines arranged in parallel with each other on a substrate and a plurality of signal lines electrically insulated from the scanning lines and arranged orthogonally are formed, and the scanning lines or the signal lines are formed. In a defect detection method of a matrix type display device in which a spare line for bypassing a disconnection portion is formed by being connected to both ends when the disconnection occurs, the luminance level is switched at mutually different timings in each horizontal scanning cycle. A defect detection method for a matrix-type display device, wherein display driving is performed by a signal. 2. A plurality of scanning lines arranged in parallel with each other on a substrate and a plurality of signal lines electrically insulated from the scanning lines and arranged orthogonally are formed, and said scanning lines or signal lines are formed. cut at the connected to the both ends broken, in the defect detection method of matrix display device spare line for bypassing the broken point is formed, the luminance levels in the mutually corresponding horizontal scanning period phase between frames A defect detection method for a matrix-type display device, characterized in that display driving is performed by signals whose switching timings are different between frames .