JPH09265063A - Device and method for inspecting liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect a defect of a drive substrate such as destruction of a thin film transistor(TFT) and a short circuit of a pixel electrode, etc., even in the state without being sealed with a liquid crystal by image processing an output signal and detecting a defective pixel in the drive substrate. SOLUTION: This device is provided with a switching means 7 connected to a video input part 4, an inspection signal generation means 8 connected to the terminal A of the switching means 7, an I/V amplifier 9 as an amplifier means connected to the same terminal B, an image inspection device 10 and a counter electrode means 100 arranged close to the pixel electrode connected to the TFT and forming a dummy pixel Cx between the pixel electrode. Then, the inspecting counter electrode means 100 is arranged on the drive substrate, and capacity is formed between with the pixel electrode by the counter electrode means 100. By detecting an electric change amount from the output signal read out from the capacity, the defective pixel of te drive substrate is detected. Thus, the pixel electrode of a liquid crystal display element is inspected even in the state without being sealed with the liquid crystal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device and inspection method for a liquid crystal display element, and more specifically, liquid crystal is sealed by arranging counter electrode means on a drive substrate to be inspected and detecting the capacitance. The present invention relates to an inspection device and an inspection method for a liquid crystal display element, which enables inspection even in a nonexistent state.

[0002]

2. Description of the Related Art Liquid crystal display devices are characterized by a flat structure and low power consumption, and are being put to practical use and becoming widespread in electronic equipment with liquid crystal display devices represented by liquid crystal projectors and laptop personal computers, televisions and the like. FIG. 3 is a diagram showing a basic configuration of a liquid crystal display device according to the present invention. The liquid crystal display device 11 in the figure includes a drive substrate 12 and a counter substrate 1.
It is roughly composed of 4. A thin film transistor (hereinafter, simply referred to as “TFT”) for controlling each pixel and a pixel electrode 13 are formed on the drive substrate 12, and a color filter CF (in the case of a color liquid crystal panel) is formed on the counter substrate 14. The black matrix BM and the transparent electrode 15 are formed. A liquid crystal display device having such a structure is called an active matrix type. The liquid crystal display device which is the object of the present invention is not limited to this structure and is merely an example.

These drive substrate 12 and counter substrate 14
Are manufactured separately in each manufacturing process. The drive substrate 12 and the counter substrate 14 that are manufactured respectively are inspected in an inspection process, and then are arranged to face each other with a predetermined gap therebetween, and the spacer 16 is sandwiched therebetween and bonded by the seal material 17. After that, the liquid crystal 18 is injected through an injection hole (not shown), and two polarizing plates (not shown) are integrally laminated on both surfaces of these glass substrates to complete the liquid crystal display device having the above configuration. The completed liquid crystal display device is connected to a test circuit, and a drive test of each pixel portion is performed to complete the liquid crystal display device.

By the way, in such a liquid crystal display device, when the TFT formed on the driving substrate 12 is broken or the pixel electrode 13 is opened or short-circuited, light is always transmitted through the polarizing plate, that is, a so-called bright spot. It becomes a defect such as a defect or a line defect. However, it is difficult to find these defects when the liquid crystal is not sealed. Especially,
It is difficult to open the pixel electrode 13 formed on the drive substrate 12 and find a short circuit between the pixel electrode 13 and the adjacent pixel portion after the display element is assembled. That is, even when a TFT or a pixel electrode 13 formed by using the integrated circuit technology has a defect in the manufacturing process, the defect remains until the liquid crystal 18 is finally sealed and inspected as a display element. However, there is a problem in that the occurrence of is not obtained as manufacturing information. Further, from the opposite point of view, there is a problem that the manufacturing cost is increased by performing the post-process on the already defective product.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to prevent defects in the drive substrate such as breakage of thin film transistors and short circuit of pixel electrodes in a state where liquid crystal is not sealed. However, it is an object of the present invention to provide an inspection device and an inspection method for a liquid crystal display device, which can improve the production efficiency of the liquid crystal display device so that the inspection can be performed.

[0006]

In order to solve the above-mentioned problems of the present invention, the following means have been taken. That is, as a basic configuration of the liquid crystal display element inspection device of the present invention, a pixel electrode arranged on the substrate in a matrix and a driving substrate including a driving unit for driving the pixel electrode In an inspection device for a liquid crystal display element that does not have a liquid crystal and is inspected during manufacturing, a counter electrode unit that is arranged with a predetermined gap on a driving substrate and forms an electric capacity with a pixel electrode, and a driving unit. A switching unit that is connected to the image input unit of the board and controls writing / reading of the inspection signal,
Inspection signal generating means for inputting an inspection signal at the time of writing the switching means, amplification means for converting the output signal into a predetermined voltage and amplifying it at the time of reading the switching means, and image processing of the output signal of the amplification means to drive substrate And an image inspection unit for detecting defective pixels.

The inspection of the liquid crystal display device of the present invention described above
The following steps are performed. In a method of inspecting a liquid crystal display device, which comprises a pixel electrode arranged in a matrix on a substrate and a driving means for driving the pixel electrode, inspecting the liquid crystal display element during manufacturing, a counter electrode is provided on the driving substrate. Means for arranging the means with a predetermined gap, forming a capacitance (dummy capacitance) between the counter electrode means and the pixel electrode, and writing / reading the inspection signal connected to the video input part of the drive substrate. Control step, inputting the inspection signal when writing the inspection signal to the drive substrate, and detecting the change in the charge amount from the dummy capacitance when reading the output signal from the drive substrate and converting / amplifying to a predetermined voltage Process,
After that, it is performed in a process including an image inspection process of image-processing the output signal of the amplification process to detect a defective pixel of the drive substrate.

According to the inspection device and the inspection method of the liquid crystal display element of the present invention, the counter electrode means is arranged on the drive substrate, and the dummy capacitor is formed between the counter electrode means and the pixel electrode to thereby perform the liquid crystal display. The element is scanned to write and read inspection signals. Since the defective pixel on the drive substrate is detected by detecting the change in the charge amount from the read output signal, the defective pixel on the drive substrate is detected even in the state where the counter substrate and the liquid crystal are not sealed. be able to. In addition, since the defective pixel is detected electrically without contact (without using a pointer or the like), a secondary defect such as a scratch does not occur in the liquid crystal display element. Furthermore, since the inspection can be performed in the state where the liquid crystal is not sealed, it is not necessary to pass the defective product to the subsequent process, and the production efficiency is improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

First, the structure of the liquid crystal display device inspection apparatus of the present invention will be described with reference to FIG. FIG. 1 is a block circuit diagram showing a liquid crystal display device inspection apparatus and inspection method according to the present invention. It should be noted that parts common to those described in the related art are designated by the same reference numerals.

This display element comprises an H shift register 1, V
Shift register 2, horizontal selector switch 3, and R,
An image input unit 4 into which G and B image signals (in the case of a color liquid crystal panel) are input is inserted. A plurality of data lines 5 are connected to the horizontal change-over switch 3 connected to the H shift register 1, and a video signal is input to each pixel section via the data lines 5. A control signal for scanning is input to the V shift register 2, and a plurality of gate lines 6 are connected via a buffer circuit (not shown). These data lines 5 and gate lines 6 are arranged in a matrix, and TFTs for switching and driving each pixel electrode are arranged at the intersections thereof. For example, the drain D of the TFT is connected to the above-mentioned data line 5, Gate G is gate line 6
, And the source S is connected to the pixel electrode 11 described above. It should be noted that the liquid crystal display element in the figure shows one of the pixels for the sake of simplicity.

On the other hand, as the liquid crystal display device inspection device (sensing unit) of the present invention, the switching means 7 connected to the above-mentioned image input section 4, the inspection signal generation means 8 connected to the terminal A of the switching means 7, The I / V amplifier 9 as an amplifying means connected to the terminal B, the existing image inspection apparatus 10 and the characteristic feature of the present invention are arranged in the vicinity of the pixel electrode (details will be described later) connected to the TFT. , Counter electrode means 100 for forming a dummy pixel Cx between the pixel electrode and the pixel electrode.

Next, the operation of the inspection apparatus and the inspection method of the liquid crystal display device of the present invention configured as described above will be described.

Referring to FIG. 1, the liquid crystal display device inspecting apparatus of the present invention receives various control signals and power supply voltages from an external IC and a power supply circuit (not shown) to receive an H shift register 1.
And V shift register 2 to activate the liquid crystal display element. Next, the switching means 7 on the sensing unit side
Is set to the terminal A side to generate the inspection signal Vi from the inspection signal generation means 8 and start writing to the liquid crystal display element via the image input section 4. The inspection signal Vi may be a DC voltage, but is preferably an AC signal in consideration of the influence on the liquid crystal display element.

The V shift register 2 generates a selection pulse every horizontal period and sequentially outputs it to the gate line 6. For example, the AC-converted all-white inspection signal Vi input through the video input unit 4 is sampled by the horizontal changeover switch 3 during the selection period of the gate line 6 and passed through the data line 5 to each pixel unit. Written in. The inspection signal Vi written in each pixel portion is held in the dummy capacitor Cx formed near each pixel portion for a predetermined period.

Next, the V shift register 2 selects the next gate line 6 ', and the inspection signal Vi is written and held in the dummy capacitor Cx connected to the gate line 6'. In this way, the scanning is sequentially performed, and the inspection signal Vi is written and held in all the pixel portions.

Subsequently, the switching means 7 is set on the terminal B side to start the read operation of the inspection signal Vi. That is, in the V shift register 2, a selection pulse is generated every horizontal period and sequentially output to each gate line 6. In response to this selection pulse, the TFT sequentially reads out the charge amount written in the dummy capacitor Cx by the above-described writing operation via the data line 5 connected to the switching circuit 4. The read charge amount is converted from current I to voltage V by the I / V amplifier 9 and amplified, and then output to the next-stage image inspection apparatus 10.

The image inspection device 10 is an existing image processing tester, and sequentially captures images displayed by the input inspection signal Vi, and performs digital filtering at high speed to extract defects. That is, by performing processing such as comparing the input inspection signal Vi with a preset reference voltage, a normal pixel and a defective pixel are instantaneously discriminated, and the discrimination result of each pixel is displayed (not shown). Display and output on a device or output device. The user takes actions such as correcting the driven substrate based on this result. It should be noted that the driven substrates are normally collectively processed in a collective state (wafer state), but can also be performed with a single liquid crystal display element.

Next, with reference to FIG. 2, the cross-sectional structure of the liquid crystal display device inspection apparatus of the present invention will be described. FIG. 2 is a sectional view showing an inspection apparatus and inspection method for a liquid crystal display element according to the present invention.

The drive substrate 12 according to the present invention in FIG.
Is a pixel electrode 13 formed on a flattening film, which will be described later, and a plurality of Ts for individually switching-driving the pixel electrode 13.
It has a conventionally known cross-sectional structure including an interlayer insulating film 19 that covers the FT and the TFT, and a flattening film 20 that is patterned and formed thereon. Drive substrate 1 having such a configuration
The counter electrode means 100, which is a feature of the present invention, is arranged on the second pixel electrode 13 with a gap of, for example, several μm to several tens of μm, and constitutes an inspection device of the liquid crystal display device of the present invention.

The counter electrode means 100 is, for example, a glass substrate provided with a transparent electrode 15 (not necessarily transparent), and the transparent electrode 15 is inspected only by approaching without applying a voltage. May be. Further, when the detected output signal is insufficient, a voltage corresponding to the common voltage may be applied to the transparent electrode 15 to efficiently extract the output signal (voltage). As described above, according to the inspection device and the inspection method of the liquid crystal display element of the present invention, the drive substrate 12 is provided even when the counter substrate and the liquid crystal are not sealed.
Defective pixels can be detected.

The drive board 1 thus inspected
2 is arranged opposite to a counter substrate (not shown) with a predetermined gap, and the liquid crystal is sandwiched in these gaps, and the periphery thereof is sealed and fixed by a sealing material. Furthermore, a liquid crystal display device is completed by integrally laminating polarizing plates (not shown) on both surfaces thereof. It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be developed into various forms.

[0023]

As described above, according to the inspection apparatus and the inspection method for a liquid crystal display element of the present invention, the counter electrode means for inspection is arranged on the drive substrate, and the counter electrode means is used to form the pixel electrode. A capacitance is formed between them. Then, the defective pixel on the drive substrate is detected by detecting the charge amount from the output signal read from this capacitance. As a result, even if the liquid crystal is not sealed, it is possible to inspect for open / short of the pixel electrode of the liquid crystal display element, and it is possible to efficiently perform quality control for the liquid crystal display element. Further, since the inspection can be performed even in a state where the liquid crystal is not sealed, there is an effect that a defective product does not need to be sent to a subsequent process and the production efficiency is improved.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a liquid crystal display device inspection apparatus and inspection method according to the present invention.

FIG. 2 is a cross-sectional view showing an inspection device and an inspection method for a liquid crystal display element of the present invention.

FIG. 3 is a schematic cross-sectional view showing a basic configuration of a liquid crystal display device according to the present invention.

[Explanation of symbols]

1 ... H shift register, 2 ... V shift register, 3 ... horizontal changeover switch, 4 ... video input section, 5 ... data line,
6 ... Gate line, 7 ... Switching means, 8 ... Inspection signal generating means, 9 ... I / V amplifier, 10 ... Image inspection device,
11 ... Liquid crystal display device, 12 ... Driving substrate, 13 ... Pixel electrode, 14 ... Counter substrate, 15 ... Transparent electrode, 16 ... Spacer, 17 ... Seal material, 18 ... Liquid crystal, 19 ... Interlayer insulating film,
20 ... Flattening film, 100 ... Counter electrode means

Claims (5)

[Claims] 1. A liquid crystal display inspecting apparatus for inspecting a driving substrate, which comprises pixel electrodes arranged in a matrix on a substrate and driving means for driving the pixel electrodes during manufacturing, A counter electrode unit arranged on the substrate with a predetermined gap to form a capacitance between the pixel electrode and the image input unit of the driving substrate, and switching for controlling writing / reading of the inspection signal. Means, an inspection signal generating means for inputting an inspection signal at the time of writing to the switching means, an amplifying means for converting and amplifying an output signal into a predetermined voltage at the time of reading out the switching means, and an image of the output signal of the amplifying means. An image inspection device for inspecting a liquid crystal display device, comprising an image inspection means for processing and detecting a defective pixel of the drive substrate. 2. The liquid crystal display element inspection device according to claim 1, wherein an item inspected by the liquid crystal display element inspection device is, in particular, an open / short state of the pixel electrode. 3. A method for inspecting a liquid crystal display device, comprising: inspecting a drive substrate, which is provided with pixel electrodes arranged in a matrix on a substrate in a matrix form, and drive means for driving the pixel electrodes, in the manufacturing method. A step of arranging the counter electrode means on the substrate with a predetermined gap, and forming a capacitance between the counter electrode means and the pixel electrode; A step of controlling writing / reading of a signal, a step of inputting an inspection signal when writing an inspection signal to the drive substrate, and a step of detecting an amount of electric charge from the capacitance when reading an output signal from the drive substrate, A liquid crystal display including: a step of converting and amplifying to a predetermined voltage; and an image inspection step of thereafter image-processing an output signal of the amplifying step to detect a defective pixel of the drive substrate. Inspection method of the child. 4. The method for inspecting a liquid crystal display element according to claim 3, wherein an item inspected by the method for inspecting the liquid crystal display element is, in particular, an open / short state of the pixel electrode. 5. A liquid crystal display device manufactured by the inspection device and the inspection method for a liquid crystal display device according to claim 1, 2, 3, or 4.