JP3479170B2 - LCD drive board inspection method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for inspecting a liquid crystal driving substrate which is a main component of a liquid crystal display panel. 2. Description of the Related Art As is well known, in a liquid crystal display panel, a glass substrate on which transparent electrodes are bonded and a liquid crystal driving substrate are opposed to each other via a spacer, and a gap between the glass substrate and the liquid crystal driving substrate is provided. It is configured by sealing liquid crystal. Various types of liquid crystal driving substrates are known depending on the driving method of the liquid crystal. FIG. 3 is a plan view showing a configuration example of an active matrix type liquid crystal driving substrate using a TFT (thin film transistor). In FIG. 1, a plurality of parallel row wirings 6, 6,... Are laid at a predetermined pitch on the surface of a glass substrate 1, and column wirings 4, 4,. The wires are arranged at a predetermined pitch. One pixel electrode 2 and one switching TFT 3 are arranged at each intersection of each row wiring and each column wiring on the glass substrate 1. Here, each TFT 3 has a source terminal connected to the column wiring 4, a drain terminal connected to the pixel electrode 2, and a gate terminal connected to the column wiring 6. The series of TFTs 3, 3,... Arranged in the row direction becomes conductive when a predetermined voltage is applied from the row wiring 6 to each gate terminal.
It is applied to each pixel electrode 2 via FT3. Here, the liquid crystal driving substrate A is in the middle of the manufacturing process, and each TF
In order to protect T3 from static electricity or the like, all the row wirings 4 are connected to the shorting bar 5, and all the column wirings 6 are connected to the shorting bar 7. However, when the liquid crystal driving substrate A is completed as a liquid crystal display panel, the shorting bars 5 and 7 are removed, and the row wirings 4 and the column wirings 6 are separated. By the way, the applicant of the present invention uses a device using an electro-optical element (modulator) having electro-optical characteristics in which the reflectivity of light is changed by an electric field, as an inspection device for the liquid crystal driving substrate A thus configured. JP-A-5-25679
No. 4 discloses this. FIG. 4 is a diagram showing a configuration of a main part of the inspection apparatus. In this figure, reference numeral B denotes a modulator. The modulator B is formed by laminating a thin film transparent electrode 11 on one side of a liquid crystal sheet 10 in which liquid crystal is sealed, and depositing or laminating a semiconductor reflecting film 12 for reflecting light applied to the modulator B on the other side. Have been. The modulator B is fixed to the inspection device, and the liquid crystal driving substrate A is arranged to face the modulator B configured as described above with a small interval (10 μm to 20 μm) and with good positional accuracy. A predetermined voltage required for inspecting the operation of the liquid crystal driving substrate A is applied to the thin film transparent electrode 11 of the modulator B and the shorting bars 5 and 7 of the liquid crystal driving substrate A by the voltage applying device C. . The surface of the modulator B is uniformly irradiated with light by the halogen lamp D. The CCD camera E captures the surface of the modulator B as one image by the reflected light from the surface of the modulator B. Next, since the liquid crystal driving substrate A is disposed opposite to the modulator B at a small interval, the liquid crystal sealed in the liquid crystal sheet 10 of the modulator B is connected to the thin film transparent electrode 11 and the liquid crystal driving electrode. It is affected by an electric field generated between each pixel electrode 2 of the substrate A. Due to the influence of the electric field, the liquid crystal sealed in the liquid crystal sheet 10 changes its molecular orientation, and changes its reflectance with respect to the light irradiated by the halogen lamp D. However, the light reflectance of the modulator B at the portion facing the pixel electrode 2 where no voltage is normally applied due to a defect such as a disconnection of the column wiring 4 or the row wiring 6 or a short circuit between the column wiring 4 and the row wiring 6 is not normal. The light reflectance of the portion facing the pixel electrode 2 to which the voltage is applied has a different value. Accordingly, an image formed by the reflected light of the modulator B captured by the CCD camera E is an image having a luminance distribution reflecting the voltage applied to the pixel electrodes 2 of the liquid crystal driving substrate A. Here, since the positional relationship between the CCD camera E and the modulator B is always constant,
The image processing apparatus F can perform a predetermined process by making an image input from the CCD camera E correspond to a predetermined address specified for each pixel electrode 2. That is,
The image processing apparatus F can perform predetermined processing by always recognizing that the image information input from the CCD camera E is information corresponding to the pixel electrode 2 of what address.
As a result, the image processing apparatus F detects the operating state of each pixel electrode 2 to determine the quality of the liquid crystal driving substrate A, and displays the result on the monitor G. [0008] Incidentally, in the modulator having the above-described structure, when a thin film transparent electrode is bonded to a liquid crystal sheet, foreign substances or bubbles may be mixed therein. The gap between the semiconductor reflection film and the liquid crystal driving substrate is 10
Due to the small size of [mu] m to 20 [mu] m, damage may be caused when a foreign substance exists between the liquid crystal driving substrate to be inspected and the semiconductor reflection film. In the modulator, such a portion where foreign matter is mixed or damaged (modulator defect)
The reflectivity of the light is lowered, and this portion cannot accurately detect a defect of the pixel electrode on the liquid crystal driving substrate. That is, conventionally, when a liquid crystal driving substrate is inspected using such a modulator, a modulator defect is determined as a defect of a pixel electrode, and thus a non-defective liquid crystal driving substrate is determined as a defective product. . In addition, due to such a problem, in the conventional method for inspecting a liquid crystal driving substrate, if the semiconductor reflection film is damaged, the modulator must be replaced promptly, so that the inspection efficiency is low and the cost is high. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a method of inspecting a liquid crystal driving substrate which suppresses determining a modulator defect as a defect of the liquid crystal driving substrate and has a high working efficiency. Aim. In order to solve the above-mentioned problems, a method for inspecting a liquid crystal driving substrate according to the present invention includes a plurality of pixel electrodes for applying an electric field to a liquid crystal and each of these pixel electrodes. A liquid crystal drive substrate formed with a circuit for applying a drive voltage to the electrodes, a transparent electrode is formed on the surface, and
A method for inspecting a liquid crystal driving substrate using a modulator having a liquid crystal sheet whose light reflectance changes depending on an electric field intensity, comprising: a. The modulator and the liquid crystal driving substrate are arranged facing each other such that the liquid crystal sheet is sandwiched between the transparent electrode and the pixel electrode; b. A predetermined voltage is applied to the shorting bar of the liquid crystal drive substrate.
Connected to the shorting bar by applying
With grounding the respective pixel electrodes, a predetermined voltage is applied to the transparent electrode of the modulator, c. Measuring the light reflection state of each part of the modulator at the time of applying the voltage in b above to determine a defective portion of the modulator and storing the defective portion in a memory; d. Applying a predetermined voltage between the transparent electrode of the modulator and each pixel electrode of the liquid crystal driving substrate; e . Measuring the reflection state of light of each part of the modulator at the time of applying the voltage of d, and detecting a defect of the liquid crystal driving substrate based on the measurement result and a defective portion of the modulator stored in the memory; It is characterized by the following. According to the method for inspecting a liquid crystal driving substrate according to the present invention, a defective portion of the modulator is determined and the defective portion of the liquid crystal driving substrate is detected in consideration of the defective portion.
A defect of the modulator is not erroneously recognized as a defect of the liquid crystal driving substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for inspecting a liquid crystal driving substrate according to the present invention will be described below with reference to the drawings. Note that the liquid crystal driving substrate to be inspected in this embodiment and the positional relationship between the modulator and the liquid crystal driving substrate at the time of inspection are the same as those in FIGS. 3 and 4 already described, and a description thereof will be omitted. FIG. 1 is a flowchart showing a method for inspecting a liquid crystal driving substrate according to the present embodiment. Hereinafter, the inspection method of this embodiment will be described in detail with reference to this flowchart. [Step S1] Mounting of Liquid Crystal Driving Substrate The liquid crystal driving substrate A is mounted on the inspection apparatus at a minute distance (10 μm to 20 μm) with respect to the modulator B by mounting means (not shown) with high positional accuracy. And
Light of uniform intensity is applied to the entire surface of the modulator B by the halogen lamp D. The CCD camera E sequentially scans the surface of the modulator B from a predetermined position. Then, by converting the reflected light obtained from each unit to a voltage corresponding to the intensity, image data representing the luminance of each unit of the modulator B is formed and output to the image processing apparatus F. [Step S2] E / O Gain Calibration In this step S2, the image processing apparatus F performs an electro-optical gain (E / O
O gain) is calculated for each pixel electrode 2. FIG.
FIG. 4 is a diagram illustrating electro-optical characteristics of a modulator B. In this figure, when the voltage E applied to the thin film transparent electrode 11 of the modulator B is increased, the reflected light amount O of the modulator B detected by the CCD camera E changes along the curve P. For example, if the voltage E is a voltage value E0 and a bias voltage,
When the voltage E applied to the thin-film transparent electrode 11 is changed from the voltage E1 to the voltage E2, the amount of reflected light detected by the CCD camera E changes substantially linearly from the amount of reflected light O1 to the amount of reflected light O2. The ratio | E2-E1 | / | O of the change amount | O2-O1 | of the reflected light amount O to the change amount | E2-E1 |
2-O1 | is the E / O gain. This E / O gain is
The values are different between the defective part of the modulator described above and the normal part. When actually obtaining the E / O gain, the voltage applying device C sets each pixel electrode 2 of the liquid crystal driving substrate A to the ground state, and first applies the voltage E1 to the thin film transparent electrode 11 of the modulator B. This voltage E1 is simultaneously stored in the internal memory of the image processing apparatus F. The image processing device F stores the voltage EO1 output from the CCD camera E at this time in an internal memory for each pixel electrode 2. Here, the liquid crystal driving substrate A is mounted on the inspection apparatus with extremely high positional accuracy. Therefore, the image processing device F stores the voltage EO1 output from the CCD camera E in the internal memory in association with the address assigned to the pixel electrode 2 in advance. Next, the voltage applying device C is a thin film transparent electrode 1
1 and the image processing apparatus F at this time
The voltage EO2 and the voltage E2 output from the CD camera E are stored in the internal memory. The image processing apparatus F adjusts the E / O gain based on the voltages E1 and E2 stored in this manner and the voltages EO1 and EO2 corresponding to the reflected light amounts O1 and O2, respectively. (Address of the pixel electrode 2), and this value is stored as E / O gain data X. This E / O gain data X is
In acquiring an image voltage in step S5 described below, the image voltage is used to calculate an image voltage from the amount of reflected light obtained for each pixel electrode 2. [Step S3] Preparation of modulator defective filter Since the amount of reflected light in the modulator defective portion described above is lower than that in the normal portion, the E / E
The O gain has a larger value than the normal part. The image processing apparatus F binarizes the E / O gain data X calculated for each pixel electrode 2 with a predetermined threshold value, and separates the E / O gain data X into a modulator defective portion and other normal portions. For example,
The defective part of the modulator corresponds to “1” and the normal part is “
0 ". This process is performed for all the pixel electrodes 2 and stored as modulator defect data R in the internal memory corresponding to the address of the pixel electrode 2. [Step S4] Substrate voltage application Then, the voltage applying device C applies a bias voltage E0 to the thin film transparent electrode 11 of the modulator B, and applies the following patterns of voltages to the shorting bars 5 and 7, respectively. A positive voltage is applied to the bar 7, and a voltage Ex is applied to the shorting bar 5. (b) The shorting bar 7 is grounded, and a voltage Ex is applied to the shorting bar 5. (c) A shorting bar 7 is applied. A positive voltage is applied to ground the shorting bar 5. [Step S5] Acquisition of image voltage Modulation is performed for each of the above voltage application patterns. The output voltage of the CCD camera E corresponding to the reflected light amount of the
It is taken in. For example, in the voltage application pattern (a), the voltage Ex is applied to the pixel electrode 2 that operates normally, and the amount of reflected light from the modulator B facing the pixel electrode 2 is the amount of reflected light Ox. However, in the case where the column wiring 4 is the pixel electrode 2 disconnected at the point x, the voltage Ex is not applied to the pixel electrode 2 in one column on the left side. Therefore, the reflected light amount of the modulator B in this portion becomes the reflected light amount Ox. It cannot be obtained, and the amount of reflected light is lower than that of other parts. In the voltage application pattern (b), when the point x and the point y of the column wiring 4 are short-circuited, the voltage Ex is applied only to the pixel electrode 2 at the upper left end, and the modulator in this portion is applied. The reflected light amount of B becomes the reflected light amount Ox.
In this case, the portion facing the other pixel electrode 2 cannot have the reflected light amount Ox, but has a low reflected light amount. Further, when the point y and the point z are short-circuited in the voltage application pattern of (c), the voltage Ex is applied only to the pixel electrode 2 at the upper left end in the same manner as described above. The light amount is the reflected light amount Ox. As described above, the amount of reflected light from the modulator B is the amount of reflected light reflecting the state of voltage application to the pixel electrode 2. The image processing device F determines the C corresponding to the amount of reflected light.
The output voltage of the CD camera E is converted into an image voltage Ey using the previously stored E / O gain data X, and this is stored in an internal memory. [Step S6] Binarization Next, the image voltage Ey calculated for each pixel electrode 2 is compared with the voltage Ex actually applied to the shorting bar 5 in step S4, and the difference is determined by a predetermined value. Is binarized depending on whether or not it is larger than the threshold value S. For example, when | Ex−Ey | <S, the pixel electrode 2 is associated with “0” as a normal pixel, and
If | Ex−Ey | ≧ S, it is associated with “1” as a defective pixel. As described above, the image processing apparatus F sets the normal pixel “0” and the defective pixel “1” for each pixel electrode 2.
Is stored as defective pixel data T. [Step S7] The filtering image processing apparatus F compares the stored modulator defect data R with the defective pixel data T for each of the same pixel electrodes 2. Then, in the defective pixel data T, “
When the pixel electrode 2 to which “1” is assigned is similarly assigned “1” in the modulator defect data R, the pixel electrode 2 is not identified as a defective pixel but is identified as a normal pixel. Such recognition is performed for all the pixel electrodes 2, and only the defective pixels due to the defect of the liquid crystal drive substrate A are detected.
In the case where there is a line defect in which defective pixels are arranged in a row in the horizontal or vertical direction in the defective pixel data T, the pixel electrode 2 to which “1” is assigned in the modulator defect data R exists in the middle of the line defect. Then, this is determined as one continuous line defect. [Step S8] The defect determination image processing apparatus F compares the allowable number of defective pixels stored in the internal memory in advance with the number of defective pixels obtained as a result of the filtering. Then, the image processing apparatus F automatically determines the quality of the liquid crystal driving substrate A from the result, displays the result of determination on the monitor G, and ends the inspection. Alternatively, the distribution of defective pixels of the liquid crystal driving substrate A is displayed as an image on the monitor G at the same time as the number of defective pixels, and the operator can determine the quality of the liquid crystal driving substrate A from the number of defective pixels and the distribution state. . According to the method of inspecting a liquid crystal driving substrate according to the present invention, the following effects can be obtained. (1) It is possible to prevent a defective portion of the modulator from being determined as a defective portion of the pixel electrode of the liquid crystal driving substrate. (2) Even if the modulator is damaged, the use of the modulator can be continued to some extent, so that the modulator can be used efficiently and is economical. (3) The number of times the damaged modulator needs to be replaced is reduced, and the inspection of the liquid crystal driving substrate can be performed efficiently, so that the inspection workability is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process chart illustrating a method for inspecting a liquid crystal driving substrate according to the present invention. FIG. 2 is a diagram illustrating electro-optical characteristics of a modulator. FIG. 3 is a plan view showing a configuration example of a TFT type active matrix type liquid crystal driving substrate. FIG. 4 is a diagram showing a configuration of a main part of a liquid crystal driving substrate inspection apparatus. [Description of Signs] A Liquid crystal driving substrate 1 Glass substrate 2 Pixel electrode 3 TFT 4 Column wiring 5, 7 Shorting bar 6 Row wiring B Modulator 10 Liquid crystal sheet 11 Thin transparent electrode 12 Semiconductor reflective film C Voltage application device D Halogen lamp E CCD camera F Image processing device G Monitor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor: Mutsumi Takeuchi 5236 Kamo, Dejima-mura, Niijima-gun, Ibaraki Prefecture Within Tsuchiura Works, Ishikawajima-Harima Heavy Industries Co., Ltd. Ishikawajima-Harima Heavy Industries, Ltd. Tsuchiura Works (72) Inventor Katsuhiro Kaji 5236 Kamo, Dejima-mura, Shinji-gun, Ibaraki Prefecture Ishikawajima-Harima Heavy Industries Co., Ltd. -1-1-16 SVAX Hamamatsucho Second Building, Photon Dynamics Co., Ltd. (72) Inventor Mike Miller 2-1-16 Hamamatsucho, Minato-ku, Tokyo SVAX Photon Dynamics Co., Ltd. (56) Reference Document JP-A-5-264462 (JP, A) JP-A-58-103605 ( JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/13-1/141 G01R 31/00

Claims (1)

(57) [Claim 1] A liquid crystal driving substrate formed with a plurality of pixel electrodes for applying an electric field to liquid crystal and a circuit for applying a driving voltage to each of the pixel electrodes. A liquid crystal driving substrate, wherein a transparent electrode is formed on a surface of the liquid crystal panel and a light reflectance of the liquid crystal sheet changes depending on an electric field intensity. The modulator and the liquid crystal driving substrate are arranged facing each other such that the liquid crystal sheet is sandwiched between the transparent electrode and the pixel electrode; b. A predetermined voltage is applied to the shorting bar of the liquid crystal drive substrate.
Connected to the shorting bar by applying
With grounding the respective pixel electrodes, a predetermined voltage is applied to the transparent electrode of the modulator, c. Measuring the light reflection state of each part of the modulator at the time of applying the voltage in b above to determine a defective portion of the modulator and storing the defective portion in a memory; d. Applying a predetermined voltage between the transparent electrode of the modulator and each pixel electrode of the liquid crystal driving substrate; e. Measuring the reflection state of light of each part of the modulator at the time of applying the voltage of d, and detecting a defect of the liquid crystal driving substrate based on the measurement result and a defective portion of the modulator stored in the memory; A method for inspecting a liquid crystal drive substrate, characterized in that: