JP3163397B2 - Method and apparatus for inspecting electrical characteristics of matrix electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix electrode for inspecting the electrical characteristics of a switch element provided at opposing electrode portions of first and second electrode members which are opposed to each other and arranged in a matrix. The present invention relates to a method and an apparatus for inspecting electrical characteristics.

[0002]

2. Description of the Related Art Conventionally, this type of inspection method is, for example, shown in FIG.
Are used in a process of manufacturing a liquid crystal display device as shown in FIG. The above-described liquid crystal display device has an ITO
(For example, display electrodes for display) Vs made of (indium tin oxide) or the like and arranged in parallel with each other.
And a switch element 20, for example, a diode, a transistor, and the like, are formed, and are deposited in the upper glass plate 17 which is parallel to the substrate 11 and opposed to the display electrode V.
A plurality of opposing electrodes (for example, scanning electrodes) Vd made of ITO or the like, which are orthogonal to s and form a matrix-structured electrode in pairs with the display electrodes Vs, are arranged. It is manufactured so that the liquid crystal 19 is held between the liquid crystal panel 17 and the liquid crystal panel 17. The drive circuit of the liquid crystal display device manufactured as described above has a circuit configuration as shown in FIG.
A switching element 20 having a current-voltage (switching) characteristic as shown in FIG. 9 is connected to a counter electrode portion between Vs3 and the scanning electrodes Vd1 to Vd3.
When a voltage is applied to the corresponding display electrode Vs and the scanning electrode Vd, an on-off operation is performed according to the electric characteristics,
The liquid crystal 19 corresponding to one pixel of display is driven to display pixel data.

If the above-mentioned switch element is defective, the display of pixels in that portion is not performed well, and the display of the entire display device is hindered. Therefore, in the conventional inspection method, all the manufacturing steps are completed. At the time when the display device was completed, the voltage applied to each of the electrodes having the matrix structure was changed using a tester or the like, and the switching characteristics of the switch element corresponding to each pixel were inspected.
That is, in the conventional inspection method, the equivalent circuit of the drive circuit for one pixel can be represented by the internal resistance R, the capacitor C, and the switch element 20, as shown in FIG.
As shown in FIG. 11A, a pulse voltage is applied to the display electrode and the scanning electrode while changing the voltage value V in sequence, and a peak current I (see FIG. 11B) flowing through the circuit is measured. It is checked whether the peak current I has the switching characteristic shown in FIG.
Judged bad.

[0004]

However, in the above-described inspection method, inspection is performed when all the manufacturing processes are completed. Therefore, when a defective product is generated, the entire display device that has been completely manufactured is discarded. However, there is a problem that the yield decreases. In addition, since the switching characteristics are inspected by changing the value of the voltage applied to each electrode, there is a problem that the inspection cannot be performed efficiently. Furthermore, in the initial manufacturing process, when performing the above-described inspection, it is necessary to align the counter electrode at exactly the same position as the electrode of the device under test in order to form a capacitor, and it is difficult to align the position. ,
In addition, since the above counter electrode forms a closed circuit with the object to be measured, it is necessary to provide wiring only for the portion where the measurement is performed, and it is actually difficult to perform the measurement in the initial manufacturing process.

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 efficiently inspect a switch element formed in an initial manufacturing process of a matrix electrode in the initial manufacturing process to improve a yield. It is an object of the present invention to provide a method for inspecting a matrix electrode that can perform the above-mentioned steps.

[0006]

In order to solve the above-mentioned object, according to the present invention, a plurality of first and second electrode members which are spaced apart from each other and arranged in a matrix are provided. In a method for inspecting electrical characteristics of a matrix electrode formed by connecting a switch element having predetermined electrical characteristics to a counter electrode portion of each of the first electrode member and the second electrode member, the electrical characteristics of the matrix electrode are inspected. On the switch element and one of the first electrode members, a transparent electrode member and an inspection member having a photoelectric material are disposed so as to be spaced apart from each other to form a capacitor equivalently, and the second electrode member and A variable voltage is applied to the transparent electrode member, and predetermined light is sequentially applied to the opposing electrode portion of the first electrode member and the transparent electrode member through an inspection member to generate a capacitance. Wherein corresponding to been variable voltage in accordance with a change in current flowing to the capacitors, electrical testing method of the matrix electrode for inspecting the electrical characteristics can be provided.

[0007]

When the switch element and one of the first electrode members are formed, a transparent electrode member and a photoconductive material are disposed on the first electrode member, and the first electrode member and the transparent electrode member face each other. The electrodes are sequentially irradiated with light, and a voltage is applied to the two electrode members to generate a capacitance. The electrical characteristics are inspected according to a change in a current flowing through the capacitor corresponding to the applied voltage. The photoconductive substance is a substance introduced in page 1931 of the first edition of the “Electronic Communication Handbook” issued on March 30, 1979 by Ohm Co., Ltd. And show conductivity when exposed to light. The voltage applied for inspection is a variable voltage, that is, a voltage whose voltage changes with time. The circuit for inspection is one terminal of the variable voltage-
> Transparent electrode member-> Photoconductive material-> First electrode member-> Switch element-> Second electrode member-> The other terminal of the variable voltage. The first electrode member and the photoconductive material are separated from each other in terms of direct current, but form a capacitor structurally. Thus, the circuit formed for testing is a closed circuit that includes a capacitor in series. When the photoconductive material is not irradiated with light, the capacitors are connected in parallel by the number of first electrode members arranged in a matrix.
When the photoconductive material is irradiated with light, the irradiated portion changes from an insulator to a conductor. The light selectively irradiates the first electrode member to be inspected. Then, the capacitance of the capacitor formed on the portion of the first electrode member corresponding to the portion irradiated with light changes in a direction in which the capacitance of the capacitor increases. That is, it is possible to select one first electrode member from a large number of first electrode members arranged in a matrix by light.

Therefore, the switch element can be efficiently inspected in the initial manufacturing process of the matrix electrode.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing the principle for carrying out the method for inspecting switching characteristics of a matrix electrode according to the present invention. In the above embodiment, the photoelectric substance 21 and the photoelectric substance 21 are provided in a part of the drive circuit including one display electrode Vs formed in the initial manufacturing process of the matrix electrode and the plurality of switch elements 20 connected to the display electrodes Vs. An inspection member 25 formed by depositing a transparent electrode 22, a transparent glass 23 as a light transmitting substrate, and an optical filter 24 that allows light of a predetermined frequency to pass therethrough is arranged in parallel with each of the display electrodes Vs, with a gap provided. To form a capacitor between both electrodes, and
A voltage is applied to the display electrode Vs and the transparent electrode 22 so that the voltage is applied .
A variable voltage V (DC voltage, AC voltage, high frequency voltage, etc.) is applied between the switch element 20 and the transparent electrode 22 . further,
One display electrode Vs is selected from the plurality of display electrodes Vs, the laser light L narrowed down to the width of the electrode Vs is scanned, and the selected display electrode Vs and the transparent electrode are scanned through the inspection member 25. Irradiation is performed on the counter electrode portion 22. As a result, a capacitance is generated between the selected display electrode Vs and the photoelectric substance 21, and as shown in the equivalent circuit of FIG. It changes according to the voltage V. Therefore, by detecting the current I flowing through the circuit that changes in response to the change in the applied variable voltage V, the switching characteristics of the switch element 20 connected to the selected display electrode Vs are shown in FIG. It can be determined whether or not the characteristics are obtained. The selection of the display electrode Vs may be arbitrary, or all the electrodes manufactured may be selected and inspected.
In FIG. 1, when the area of the transparent electrode 22 is very small, the capacity of the formed capacitor C becomes small, and it becomes difficult to measure the current. Therefore, the ferroelectric material 26 is arranged in a gap between the display electrode Vs and the inspection member 25,
It is also possible to increase the capacity of the capacitor C.

FIG. 3 is a block diagram showing the configuration of an inspection apparatus for implementing the method of inspecting switching characteristics of a matrix electrode according to the present invention. In the figure, the main control unit 30
Controls the object supply unit 31, the stage control unit 32, the measurement control unit 33, the signal processing unit 34, the data processing unit 35, and the display unit 36 as a whole. The measured object supply unit 31 includes:
One of the display electrodes Vs shown in FIG.
An object to be measured, which is a part of a drive circuit composed of a plurality of switch elements 20 connected to the first stage 37, is supplied onto the first stage 37, and when the inspection is completed, the object to be measured on the first stage 37 is replaced. I do.

The stage controller 32 controls the driving of a first stage 37 on which the object to be measured is mounted and a second stage 38 which holds the inspection member 25, and inspects the object to be measured and the inspection member 25. By moving to the reference position, a predetermined gap is provided between the display electrode Vs of the device under test and the photoconductive material 21 of the inspection member 25. The measurement control unit 33 includes a device for inspecting the switching characteristics of the device under test, for example, an oscillator 39 for oscillating predetermined light such as a laser beam,
Control of the light scanning unit 40 that scans predetermined light from the camera, position detection of the stages 37 and 38, the DUT and the inspection member 25.
It controls the application of a variable voltage to the device and the measurement of the switching characteristics of the device under test.

The signal processing unit 34 processes the signal output from the measurement control unit 33. For example, the signal processing unit 34 detects the current I flowing through the circuit of the device under test (see FIG. 2) measured by the measurement control unit 33. The signal is being processed. Data processing unit 35
Performs data processing based on the signal processed by the signal processing unit 34. For example, data of switching characteristics is created from the processed signal of the current I, and the data is excellent in comparison with the reference switching characteristics. Determine if it is a characteristic.

The display unit 36 displays the result of the above-mentioned judgment and the like from the data processing unit 35, and displays, for example, the presence / absence of a defect or a defect location using a map. The oscillator 39 oscillates predetermined light such as laser light, for example, and emits the predetermined light to the optical scanning unit 40. The predetermined light is not limited to laser light, but may be any type of light, such as white light, as long as it can be converged on the width of the display electrode Vs.

The light scanning section 40 scans and irradiates predetermined light incident from the light scanning section 40 on the transparent electrode 22 of the inspection member 25 and the counter electrode section of the selected display electrode Vs of the device under test, for example, a galvanometer. It is composed of an optical system such as a mirror, a polygon mirror, and a condenser lens. Thus, in the present embodiment, the measurement control unit 33 causes the laser beam emitted from the oscillator 39 to be opposed to the transparent electrode 22 of the inspection member 25 and the selected display electrode Vs of the device under test via the optical scanning unit 40. By irradiating the electrode section and applying a variable voltage V to the transparent electrode 22 and the display electrode Vs, a change in the peak current I flowing through the circuit of FIG. 2 is measured. The data processing unit 35 obtains the switching characteristics of each display electrode Vs based on the change data of the peak current I input via the signal processing unit 34, and determines whether the switching characteristics of each display electrode Vs are good. If it is good, an indication that the switching characteristics are good is displayed on the display unit 36, and if it is bad, an indication that the DUT is defective is displayed on the display unit 36.

Therefore, in the present embodiment, a part of the drive circuit including one display electrode Vs formed in the initial manufacturing process of the matrix electrode and the plurality of switch elements 20 connected to each of the display electrodes Vs. At this stage, the switching characteristics of the matrix electrode can be optically inspected,
Even an object to be measured having a large number of pixels can be inspected quickly without being destroyed.

In the present embodiment, the transparent electrode 22 of the inspection member 25 has a flat plate configuration, but the present invention is not limited to this, and may be configured in a linear configuration, for example. In this case, as shown in the plan views of FIGS. 4 and 5 and the cross-sectional view taken along the line AB, each display electrode Vs (see FIG. 1) is separated from and opposed to each display electrode Vs (see FIG. 1). The transparent electrode lines 22a arranged perpendicular to Vs are made parallel to each other and separated by a predetermined distance k, and are paired with the display electrodes Vs to form an electrode having a matrix structure. And
The scanning of the laser beam is performed as in the scanning example of the laser beam shown in FIG. That is, the light scanning unit 40 (see FIG. 3)
Irradiates the selected display electrode Vs and the opposite electrode portion 41 of the transparent electrode 22a with the laser light L narrowed down to the width of the display electrode Vs, and when the measurement is completed, the laser light L is sequentially scanned as shown by a dotted line. And the next selected display electrode Vs
To the opposite electrode portion 41 of the transparent electrode 22a.
The measurement control unit 33 (see FIG. 3) evaluates and tests the switching characteristics of the switch element 20 of the counter electrode unit 41. The switch elements 20 to be measured are commonly wired.

Thus, when the inspection member 25 is irradiated with the laser beam L, only the irradiated portion of the transparent electrode line 22a becomes an electrode, and the selected display electrode Vs and the photoconductive material 2
A capacitance is generated between the two. The size of the electrode can be made variable by the beam diameter of the laser beam L.
Therefore, in the present embodiment, since the measurement position is scanned by the light beam (laser light), a wide range can be scanned at a high speed, and the position alignment of the counter electrode portion is facilitated. Also, the position can be easily changed. Further, since the measurement position is exclusively selected with the other switch elements, only one wiring of the counter electrode is possible. Further, in the present embodiment, since the alignment of the measurement position can be performed optically, the adjustment and management of the measurement position are easier than the case where the mechanical alignment is performed.

[0018]

As described above, according to the present invention, a plurality of first electrode members and a plurality of second electrode members which are spaced apart from each other and arranged in a matrix are provided, and
In the method for inspecting electrical characteristics of a matrix electrode, the electrical characteristics of a matrix electrode formed by connecting a switch element having predetermined electrical characteristics to a counter electrode portion of an electrode member and a second electrode member are inspected. On the switch element and one of the first electrode members, a transparent electrode member and an inspection member having a photoelectric material are disposed so as to be spaced apart from each other to form a capacitor equivalently, and the second electrode member is formed. And applying a variable voltage to the transparent electrode member, and irradiating a predetermined light through the inspection member sequentially to the opposing electrode portion of the first electrode member and the transparent electrode member to generate a capacitance. The electrical characteristics are inspected in accordance with the change in the current flowing through each of the capacitors corresponding to the variable voltage, so that the inspection can be performed in the initial stage of the manufacture of the matrix electrode, thereby reducing the yield. It is possible to above may be further by utilizing photoelectric effect will be able to inspect the optically switching characteristics, this order without destroying the object to be measured, and quickly inspected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle for carrying out a method for inspecting switching characteristics of a matrix electrode according to the present invention.

FIG. 2 is a diagram showing an equivalent circuit of FIG. 1;

FIG. 3 is a block diagram showing a configuration of an inspection apparatus for implementing a switching characteristic inspection method for a matrix electrode according to the present invention.

FIG. 4 is a plan view showing the principle of an inspection member according to another embodiment of the present invention.

FIG. 5 is a sectional view taken along a line AB in FIG. 4;

FIG. 6 is a view for explaining a scanning method of a laser beam in another embodiment of FIG. 4;

FIG. 7 is a cross-sectional view illustrating a cross section of one pixel in a liquid crystal display device.

FIG. 8 illustrates a driving circuit in a liquid crystal display device.

FIG. 9 is a diagram showing switching characteristics of a switch element.

FIG. 10 is a diagram showing an equivalent circuit of the drive circuit shown in FIG.

11 is a diagram showing a variable voltage applied to the equivalent circuit of FIG. 10 and a peak current flowing in the equivalent circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 19 Liquid crystal 20 Switch element 21 Photoconductive substance 22 Transparent electrode 23 Transparent glass 24 Optical filter 25 Inspection member 26 Ferroelectric 41 Counter electrode part V Variable voltage Vs Display electrode L Laser light C Capacitor

Claims (3)

(57) [Claims] A plurality of first electrode members and a plurality of second electrode members which are spaced apart from each other and are arranged in a matrix; and a predetermined electrode member is provided on each of the first electrode member and the second electrode member. In a method for inspecting electrical characteristics of a matrix electrode formed by connecting switch elements having electrical characteristics of the matrix electrode, the electrical characteristics of the matrix electrode are inspected.
A transparent electrode member and an inspection member having a photoconductive material are disposed so as to be spaced apart from each other to form a capacitor equivalently, a variable voltage is applied to the second electrode member and the transparent electrode member, and the inspection member is The first electrode member and the transparent electrode member are successively irradiated with predetermined light to generate electrostatic capacity, and a capacitance is generated, according to a change in current flowing through each of the capacitors corresponding to the applied variable voltage. And inspecting the electrical characteristics of the matrix electrode. A plurality of first electrode members and a plurality of second electrode members which are spaced apart from each other and arranged in a matrix, and a predetermined electrode member is provided on each of the opposed electrode portions of the first electrode member and the second electrode member. In a device for inspecting electric characteristics of a matrix electrode formed by connecting a switch element having the electric characteristics described above, the electric characteristic of the matrix electrode is separated from the formed switch element and one of the first electrode members. A test member having a transparent electrode member and a photoconductive material which are disposed to face each other and equivalently form a capacitor;
Voltage applying means for applying a variable voltage to the second electrode member and the transparent electrode member;
A light irradiating means for sequentially irradiating the electrode member and the opposing electrode portion of the transparent electrode member; and a variable capacitance applied to the opposing electrode portions of both electrode members by the irradiating light. An inspection device for inspecting the electrical characteristics according to a change in current flowing through the capacitor corresponding to a voltage; 3. The apparatus according to claim 2, wherein the inspection member has a ferroelectric material for increasing the capacitance of the capacitor, in addition to the transparent electrode member and the photoconductive material. .