JPH023022A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To speedily pinpoint the shorted location of a shared electrode and a signal line, or the electrode and a scanning line by forming a slit in the direction of the signal line in contact with a liquid crystal cell or in the direction intersecting orthogonally with the scanning line and dividing the shared electrode into plural regions. CONSTITUTION:The slit 7 is formed in the direction intersecting orthogonally with the signal line 41 in contact with the liquid crystal cell, far instant, and the shared electrode 1 is divided into plural regions. If in the shared electrode 1, one region divided by the slit 7 and the signal line 4i or the scanning line 5j to which a voltage different from the potential of a power source 6 is applied are shorted, a voltage in the shorted region is different from a voltage in non- shorted region in the shared electrode 1. That difference affects the display of a liquid crystal display device. As a result, the shorted location is quickly pinpointed to repair it.

Description

[Detailed description of the invention]

[Overview] Regarding active matrix type liquid crystal display devices, a common electrode is provided on one side with the liquid crystal cell in between, with the aim of quickly finding short-circuit points between the common electrode and the signal line or scanning line. , on the other side, a pixel electrode provided for each pixel, a switching element for driving the pixel electrode, and a signal line and a scanning line wired to cross each other to drive the switching element. In the active matrix liquid crystal display device, the common electrode is divided into a plurality of regions by forming slits in the common electrode in a direction perpendicular to the signal line or the scanning line in contact with the liquid crystal cell. Configure it as follows. [Industrial Application Field] The present invention relates to an active matrix type liquid crystal display device. In recent years, in order to avoid problems such as crosstalk, active matrix type liquid crystal display devices have been developed, in which a pixel electrode is provided for each pixel, and each pixel electrode is driven by a switching element. It is used. Incidentally, in such an active matrix type liquid crystal display device, a solid electrode is provided as a common electrode on one side of the liquid crystal cell, and the above-mentioned pixel electrode and corresponding switching element are arranged on the other side. The switching elements are driven by scanning lines and signal lines arranged in a grid pattern. However, in order to speed up the response speed to switching and improve image quality, the thickness of the liquid crystal cell tends to become thinner, and the common electrode and the signal line or scanning line may short-circuit and cause line defects. A situation is occurring. In such a case, it is necessary to quickly find and repair the short circuit. Therefore, there has been a need for a technique for quickly discovering a short-circuit between a common electrode and a signal line or a scanning line in an active matrix liquid crystal display device. [Prior Art and Problems to be Solved by the Invention] FIG. 5 is a diagram schematically showing a configuration for applying voltage to a liquid crystal material in a conventional active matrix type liquid crystal display device. In Fig. 5, 1' is a common electrode, 2 +1+ 21
2+2゜1.2□2 is the pixel electrode, 311+ 312+
321+322 are switching elements, 43.4
□ is a signal line, 5. ．． 5□ is a scanning line, 6 is a ground, and 8 is a glass substrate. Note that, for simplicity, the matrix has two rows and two columns. Pixel electrode 2 +1+ 212+ 221+ 22
2. Switching elements 311+ 312+ 321
+322, signal line 48.4□, scanning line 5i. 5□ is formed on the glass substrate 8 by a normal semiconductor manufacturing method. In a liquid crystal display device, although not shown, there is a layer of liquid crystal material (liquid crystal cell) sandwiched between alignment films and surrounded by a sealant between the common electrode layer and the glass substrate 8. , a voltage is applied to the liquid crystal cell through the above electrodes. By the way, the thickness of the liquid crystal cell is usually several μm, and in order to increase the response speed to switching and improve the image quality, the thickness of the layer of the liquid crystal material is
It tends to become thinner. Therefore, a situation occurs in which the common electrode and the signal line or the scanning line are short-circuited, resulting in a line defect. In such cases, it is necessary to quickly find and repair the short circuit, but since the common electrode in conventional liquid crystal display devices is a solid electrode, it is difficult to identify the defective point. . The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a liquid crystal display device in which a short circuit between a common electrode and a signal line or a scanning line can be quickly discovered. [Means for Solving the Problems] FIGS. 1A and 1B are diagrams showing the basic configuration of the present invention. In FIGS. 1A and 1B, 1 is a common electrode, 2 is a pixel electrode, and 30. is a switching element; 4. 1 is a signal line, 5 is a scanning line, 6 is a predetermined voltage source, and 7 is a slit. In addition, i=l~m. Let j=1 to n. The common electrode 1 and the second pixel electrode are present on both sides with a liquid crystal cell (not shown) in between. The second pixel electrode is provided for each pixel in order to apply a voltage to the portion corresponding to each pixel of the liquid crystal cell. Each switching element 3 IJ is provided to drive the corresponding pixel electrode 21J,
Furthermore, the switching element 3. ．． A signal line 41 and a scanning line 5. are wired to cross each other in order to drive the signal line 41 and the scanning line 5. is provided. As a feature of the present invention, a slit 7 is formed in the common electrode 1 in contact with the liquid crystal cell, for example, in a direction perpendicular to the signal line 41, and the common electrode 1 is divided into a plurality of regions. [Function] A voltage different from the potential of the voltage source 6 connected to the common electrode 1 is applied to the signal line or scanning line 5. to be tested for short circuit with the common electrode 1. are applied in sequence. At this time, if a voltage different from the potential of the voltage source 6 described above is applied to one region of the common electrode 1 in FIG.
If J is short-circuited, the difference between the applied voltage and the voltage of the voltage source 6, and the one area of the common electrode 1 between the short-circuit point of the common electrode 1 and the voltage source 6. A current flows depending on the electrical resistance in the one region, that is, a voltage drop occurs in the one region. However, 1. - the current, and hence the voltage drop, does not affect the other region of the common electrode 1 divided by the slit 7, because the influence of the voltage drop does not extend to the other region of the common electrode 1 divided by the slit 7. This is because the current path leading to the capacitor becomes longer and the resistance becomes larger. In this way, the voltage of the common electrode 1 differs between the region where the short circuit occurs and the region where it does not occur, and this appears in the display of the liquid crystal display device. This is the basic principle for identifying short circuit locations in the liquid crystal display device according to the invention. [Embodiment] FIG. 1 shows the arrangement of a TPT matrix, data bus line, and scan path line in a liquid crystal display device according to an embodiment of the present invention. The configuration shown in FIG. 4 corresponds to the configuration on the glass substrate 8 in the configuration shown in FIG.
In other words, thin film transistors are arranged in a matrix. In FIG. 4, 2L is a pixel electrode, 30IJ is the staggered TFT, and 311J is the TFT 304. gate electrode of 32. J is the drain electrode of the TFT 30ij, 40. is the data bus line, and 50° is the scan path line. Here, it is assumed that 1-1 to m and j=l to n. The scan path line 50J is the TFT 301J of each row.
(1=1~m) gate electrode w"l11.+(+"1
~m) and connected to the data bus line 40. is T of each column
Drain electrode 32 of FT30+j (J = l~n).
Connected to 4. And each piece FT30. J(i=1~
rn, j=i−n) are connected to the corresponding pixel electrodes 2υ1. +(+=1 to m, )=i to n). Each scan path line 50. A valid electrical signal is periodically applied to the scan bus line 50, and the TFT3 LJ (i=l to m) connected to the scan bus line 50 is turned on only at this time, and at the same time the signal is input to the data bus line 40+. A voltage corresponding to the image data is applied to the connected pixel electrode 20. applied to J. Here, the above scan path line 50. and data bus line 40. are bare metal wires formed in sequence on the glass substrate as described above, and are opposed to a common electrode via a liquid crystal cell (liquid crystal material) of several μm. Therefore, a short circuit may occur between the data bus line and the common electrode that are in contact with the liquid crystal material. Incidentally, when an inverted staggered TPT is used, the scan path line is in contact with the liquid crystal material. The configuration of the common electrode 10 in the liquid crystal display device according to the embodiment of the present invention is shown in FIG. In the common electrode 10 of FIG. 2, the scan path line 50 of FIG. Slabs) 70J (J=] to n) are provided at positions corresponding to J-1 to J-n in a direction perpendicular to the data bus line, and the common electrode 10 is connected to the extension of the data bus line. In addition, FIG. 3 shows how the common electrode 10 of FIG. 2 is superimposed on the structure consisting of the TPT matrix, scan path line, and data bus line of FIG. 4. It is shown. In the liquid crystal display device according to the embodiment of the present invention described above, the procedure for detecting a short circuit between the common electrode 10 and the data bus line 40 is as follows. First, electrical continuity between each data bus line 40+ and the common electrode 10 is detected using a resistance measuring device or the like. Next, an electric signal for performing predetermined blinking is manually applied to the data bus line 4 (It) which is electrically connected to the common electrode 10. Here, as described above, the second
As shown, the common electrode 10 connects the data bus lines 40. Since the scan path line 50J is divided perpendicularly to the position of each scan path line 50J, voltage fluctuation occurs along the region of the divided region of the common electrode IO that is short-circuited to the data bus line 40t. A current flows along the short-circuited region between the short-circuited point and a voltage source of a predetermined potential, such as ground, to which the common electrode 10 is connected. At this time, the voltage fluctuation at the common electrode 10 appears in the display of the liquid crystal display device. That is, along the region short-circuited to the data bus line 40+, a change in the display according to the electric signal for performing the predetermined blinking is observed. For example, at point "S" in FIG. , and the common electrode 10, a voltage fluctuation occurs in the region between the ribs 701 and 70□ of the common electrode 10, and the pixel electrodes 20+, A voltage is applied to the portion between (i=1 to n), and this is observed as a change in the transmittance of the liquid crystal cell. In this manner, in the liquid crystal display device according to the embodiment of the present invention, the position of the pass line that is short-circuited to the common electrode 10 can be quickly discovered. The above-mentioned short-circuited portion is separated and repaired using, for example, a laser. The slit 70 as shown in FIG. 2 is formed by patterning the glass substrate on the common electrode side in the shape of the slit 70 in FIG. ) is formed into a film, and then the transparent electrode in the slit 70 portion is lifted off. According to the configuration of the embodiment of the present invention, as shown in FIG. 3, the slit 70 of the common electrode 10 is aligned with the scan path line 50. Therefore, a short circuit between the common electrode 10 and the scan path line 50j is less likely to occur. [Effects of the Invention] In the active matrix liquid crystal display device according to the present invention, a short circuit between a common electrode and a signal line or a scanning line can be quickly discovered. 4i

[Brief explanation of the drawing]

FIG. 1A and FIG. 1B are diagrams showing the principle configuration of the present invention. FIG. 2 is a diagram showing the configuration of a common electrode in an embodiment of the present invention. FIG. 3 is a diagram showing the common electrode and TPT matrix side in an embodiment of the present invention. FIG. 4 is a diagram showing the arrangement of the TPT matrix, data bus line, and scan path line, and FIG. 5 is a diagram showing the voltage in a conventional active matrix liquid crystal display device. FIG. 2 is a diagram schematically showing a configuration for application. [Explanation of symbols] 1, l', 10... common electrode, 2Ij, 201j...
・Pixel electrode, 3B... switching element, 4.41・
...Signal line, 5,5j...Scanning line, 6...Voltage source,
? , 70°...Slit, 8...Glass substrate, 30
iJ...thin film transistor, 31st...gate electrode of thin film transistor, 32nd...drain electrode of thin film transistor, 40r...data bus line, 50
j...Scan path line. Principle-conventional diagram of the present invention Part 1 Partial enlarged view of the “” part in Figure A Figure 1B

Claims (1)

[Claims] 1. A common electrode (1) is provided on one side of the liquid crystal cell, and a pixel electrode (2_) provided for each pixel is provided on the other side.
i_j), a switching element (3_i_j) that drives the pixel electrode (2_i_j), and a switching element (3_i_j) that drives the pixel electrode (2_i_j).
In an active matrix liquid crystal display device comprising a signal line (4_i) and a scanning line (5_i) wired to cross each other to drive a signal line (4_i) and a scanning line (5_i) for driving a signal line (3_i_j), A liquid crystal display device characterized in that the common electrode (1) is divided into a plurality of regions by forming a slit (7) in a direction perpendicular to a signal line or a scanning line in contact with the liquid crystal cell.