JPH1062451A - Board tester for liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a board tester in which a contact unit can be replaced easily for various boards while reducing the side. SOLUTION: The board tester 20 comprises a contact unit 22 including probes corresponding to large number of drain electrode pads 12 arranged along the circumferential fringe of a liquid crystal display(LCD) 10 and a plurality of flexible printed wiring boards(FPC) 26 on which a print wiring 25 conducting to the probes is formed. Each FPC 26 is connected to the tester T side and respective probes integrally touching respective electrode pads 12 are conducted to the tester T thus performing array test of an LCD board 10. A multiplexer 53 for switching each print wiring 25 sequentially is connected with each FPC 26 on the drain electrode pad 12 side and the multiplexer 53 is connected with the tester T through a flat cable 27 having smaller number of wiring than the print wiring 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a substrate for a liquid crystal display (hereinafter, referred to as an "LCD substrate").

[0002]

2. Description of the Related Art A conventional LCD substrate inspection apparatus is an LCD substrate inspection apparatus.
It has a mounting section for mounting the substrates in a cassette, a transport mechanism for transporting the LCD substrates one by one from the mounting section, and an inspection section for inspecting the LCD substrates transported by the transport mechanism. It is configured. Inspection unit is LCD
A mounting table on which the substrate is mounted is movable in X, Y, Z, and θ directions, and a contact unit having a probe that contacts a gate electrode and a drain electrode of the LCD substrate on the mounting table.

For example, as shown in FIG.
The reference numeral 0 denotes a rectangular glass substrate 11, for example, 1920 pieces in the horizontal direction (hereinafter, referred to as “X direction”) and the vertical direction (hereinafter, referred to as “Y direction”) on substantially the entire surface of the glass substrate 11. ) Has 480 thin film transistors (hereinafter referred to as “TF”).
T ". ) (Not shown) are arranged in a matrix. A drain line (not shown) formed in the Y direction is connected to a drain electrode of each TFT, and a drain electrode pad (hereinafter, referred to as a “drain electrode pad”) 12 is provided at an upper end of each drain line.
Are formed respectively. A gate line (not shown) formed in the X direction is connected to the gate electrode of each TFT, and a gate electrode pad (hereinafter, referred to as a “gate electrode pad”) is provided at the left end of each gate line.
13 are formed respectively.

On the other hand, as shown in FIG. 4, the inspection device 20 includes a contact unit 2 that contacts each drain electrode pad 12 and gate electrode pad 13 at a time.
1, 22 and these contact units 21, 2
Conduction between the LCD substrate 10 and a tester (not shown) via the second substrate 2 is performed, and an inspection (array inspection) is performed for the presence or absence of a defect in an electric circuit such as a TFT constituting each pixel formed on the glass substrate 11. It is like that.

As shown in FIG. 5, the contact unit 21 on the side of the drain electrode pad 12 is
A plurality of probes 23 corresponding to the respective drain electrode pads 12, a plurality of pin blocks 24 incorporating these probes 23, and a printed wiring 25 connected to each probe 23 of these pin blocks 24 (see FIG. 4). ) Are formed and a plurality of flexible printed wiring boards (hereinafter, referred to as “FPC”) 26 are formed. Each FPC 26 is connected to a flat cable 27, and each flat cable 27 is connected to a motherboard (not shown) of the tester T via a connector 28. Further, the plurality of pin blocks 24 are fixed to a mounting frame (not shown) and integrated as a contact unit 22,
Each drain electrode pad 12 is brought into contact collectively. In FIG. 5, 29 is the FPC 25
Is attached to the pin block 24 using screws or the like.

As shown in FIG. 4, the contact unit 22 on the gate electrode pad 13 side has probes (not shown) corresponding to the respective gate electrode pads 13 on the LCD substrate 10 and upper ends of these probes. It has an FPC 31 on which printed wiring lines 30 connected to each other on the upper surface of a pin block (not shown), a TAB 32 connected to each FPC 31, and a printed circuit board 33 connected to these TABs 32. The TAB 32 is mainly composed of a driver IC 34, scans a voltage applied to the gate electrode of the LCD substrate 10 by the driver IC 34 at the time of inspection, and incorporates a detected drain current from the contact unit 21 into a tester in synchronization with the scanning. Through the scanner that has been loaded into the tester
An array inspection of the D substrate 10 is performed. Each of the pin blocks is fixed to a mounting frame (not shown) similarly to the above-described pin block 24, and is integrated therewith so as to collectively contact each of the gate electrode pads 13. The FPC 31 and the TAB 32 are pressed by a heat seal method or the like.

The FPC 26 of the contact unit 21 on the drain electrode pad 12 side is connected to the motherboard of the tester T via a flat cable 27 as shown in FIG.
The pitch between them is extremely narrow, for example, about 70 to 90 μm ,
At such a narrow pitch, the printed wiring 25 of the FPC 26 is used.
4 cannot be directly connected to the pins of the connector 28, the pitch of the printed wiring 25 is formed so as to gradually increase from the middle according to the pin pitch of the connector 28 as shown in FIG. 4, and the FPC 26 becomes wider from the middle. .
In the future, as the definition of the LCD becomes higher, the pitch of the printed wiring 25 will be further narrowed accordingly.

[0008]

However, in the case of the conventional inspection apparatus, all the detected drain currents from each drain electrode pad 12 are simultaneously taken into the tester T via the contact unit 21 and the flat cable 27. Therefore, the number of the printed wirings 25 of the FPC 26 drawn from the pin block 24 increases with the increase in the definition of the LCD, and accordingly, the width of the FPC 2 becomes wider and wider.
4 and the FPCs 26 interfere with each other as shown in FIG. There was a problem of becoming. When a plurality of types of LCD substrates 10 are inspected, the contact unit 21 is exchanged according to the type of the LCD substrate 10.
Each time the type of the substrate 10 changes, the contact unit 21
And the replacement of the cable 27 for connecting the tester T to the tester T is required, and as the number of connectors 28 increases, the replacement work becomes extremely troublesome, which causes a reduction in inspection efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can reduce the size of a tester and easily replace a contact unit with various liquid crystal display substrates. It is an object of the present invention to provide an apparatus for inspecting a substrate for a liquid crystal display, which can enhance the inspection efficiency.

[0010]

According to a first aspect of the present invention, there is provided an apparatus for inspecting a substrate for a liquid crystal display, wherein a plurality of gate electrodes and a plurality of drain electrodes are arranged along the periphery of the substrate for a liquid crystal display. A contact unit having a corresponding contact terminal and a plurality of flexible printed wiring boards on which printed wirings respectively conducting with these contact terminals are formed, and connecting each of the printed wiring boards to a tester side; In an inspection apparatus for conducting an array inspection of a substrate for a liquid crystal display by conducting a test terminal with each of the contact terminals which have been brought into contact with the electrodes collectively, a switching circuit for sequentially switching each of the printed wirings is provided on each of the printed wirings on the drain electrode side. A switching circuit and the tester are connected to each other with less wiring than the number of the printed wirings. A.

According to a second aspect of the present invention, there is provided an apparatus for inspecting a substrate for a liquid crystal display, wherein a connector is provided on a wiring on the tester side of the switching circuit in the first aspect. It is assumed that.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. Inspection device 20 of the present embodiment
As shown in FIG. 1, the contact units 21 and 2 contact the drain electrode pad 12 and the gate electrode pad 13 at the upper edge and the lower edge of the LCD substrate 10, respectively.
2 to make the LCD substrate 10 and the tester T conductive through these contact units 21 and 22,
An array inspection of the substrate 10 is performed. That is, as shown in FIGS. 1 and 2, the contact unit 21 includes a pin block 24 having a built-in probe 23 corresponding to each drain electrode pad 12 of the LCD substrate 1, and a probe 23 of these pin blocks 24. A plurality of FPCs 26 each having a printed wiring 25 connected thereto, a TAB 50 connected to each FPC 26,
B50 and a printed board 52 connected via a connector (connection plate) 51. The printed circuit board 5
2 and the tester T are connected via a flat cable 27. FIG. 1 shows a state in which the connection plate 51 is removed.

The TAB 50 has, for example, a multiplexer IC (hereinafter simply referred to as a “multiplexer”) 53 shown in FIG. 3 as a switching circuit, and sequentially switches the probes 23 of the pin block 24 via the multiplexer 53. The detected drain current is sequentially taken into the tester T via the printed board 52 and the flat cable 27, and the array inspection of the LCD board 10 is performed. That is, in the TAB 50, the number of the wirings 50B on the output side is significantly reduced as compared with the number of the wirings 50A on the input side of the TAB 50 via the multiplexer 53. Therefore, the number of output-side wirings 50B is reduced, so that TAB 50
Since the number of subsequent wirings is much smaller than in the past, the number of wirings after TAB50, the number of connectors on the tester T side, etc. will increase significantly even if the pitch of the drain electrode pad 12 becomes narrower in the future. The tester T does not increase in size. The FPC 26 and the TAB 50 are pressure-bonded by a heat sealing method or the like.

The probe 23 and the flat cable 27
2 is shown in FIG. That is, the probe 23 is built in the pin block 24 corresponding to the drain electrode pad 12, and is constituted by, for example, a pogo pin. The upper and lower ends of each probe 23 slightly protrude from the upper and lower surfaces of the pin block 24, the lower end elastically contacts the drain electrode pad 12, and the upper end elastically contacts the printed wiring 25 of the FPC 26. Each printed wiring 25 is connected to an input terminal 50A of the TAB 50. The connection plate 51 is made of, for example, TAB.
The pogo pins 51A correspond to the output terminals 50B of the TAB 50, respectively.
0B, and the upper end of each pogo pin 51A is in elastic contact with a printed wiring circuit (not shown) of the printed circuit board 52. Further, the flat cable 27 is connected to the output side of the printed circuit board 52. Other configurations are configured according to the conventional inspection apparatus. In FIG. 1, reference numeral 35 denotes a flat cable.

FIG. 3 schematically shows the multiplexer 53, for example. This multiplexer 5
Reference numeral 3 has, for example, an input terminal 53A and one output terminal 53B connected to 16 printed wirings 25 formed on the FPC 26, for example. The multiplexer 53 switches the input terminals 53A based on a control signal S1 (see FIG. 1) input from the tester T via the control signal wiring 27A and the printed circuit board 52, and sequentially switches the output terminals 5A.
3B, and sequentially transmits the detected drain currents (parallel signals) inputted in parallel from the 16 input terminals 53A to the tester T from one output terminal 53B as serial signals arranged in series with a time difference. I have to do it.
Therefore, if there is one output terminal 53B for 16 input terminals 53A, the tester T can detect the detected drain current of the probe 23 with respect to the tester T without leakage. As the number of input terminals 53A increases, the reduction rate of the output terminals 53B increases, and the number of wirings connected to the tester T decreases significantly. Thus, the multiplexer 53
The number of wirings on the tester T side can be reduced to about 1/20 of the number of wirings on the probe 23 side, for example.

An amplifier 54 and an A / D converter 55 are connected to an output terminal 53B of the multiplexer 53. The amplifier 54 amplifies a minute detection drain current output from the multiplexer 53, and outputs an amplified analog signal. Is converted into a digital signal by an A / D converter 55, and an amplifier 54 is output based on a control signal S2 from the tester T.
The CPU 56 processes the digital signals sequentially output from the CPU and detects the presence or absence and location of a pixel defect on the LCD substrate 10 based on the detection signal. The amplifier 54, A / D converter 55 and CP
U56 and the like are built in the tester T.

Next, the operation will be described. LCD board 1
In the case of performing the electrical inspection of 0, the mounting table moves in the X, Y, and θ directions under the control of the control device, and the drain electrode pads 12 and the gate electrode pads 13 of the LCD substrate 10 are connected to the contact unit 21. , 22 each probe 23
Align to. Thereafter, the mounting table is raised, and when a predetermined operation is performed, the probe 23 causes the electrode pads 12,
13, and the electrode pads 12, 13 and the tester T are electrically connected via the probe 23. Here, when the driver IC 34 is driven based on the signal from the tester T, the multiplexer 53 is driven in synchronization with the driving, and the detected drain current is sequentially taken into the tester T from the printed wiring 25 of each FPC 26.

At this time, the printed wiring 25 of each FPC 26
All the detected drain currents are drain electrode pad 12
, And flows in parallel to all the input terminals 53A of the multiplexer 53. These parallel signals are sequentially supplied to each input terminal 53A by the multiplexer 53 driven based on the control signal S1 from the tester T. The signals are switched and rearranged in series with a time difference, and sequentially output from the output terminal 53B to the tester T as a serial signal. In the tester T, the serial signal input from the multiplexer 53 is amplified by the amplifier 54, and the amplified serial signal sequentially output from the amplifier 54 is sequentially converted from an analog signal to a digital signal by the A / D converter 55, The signal is signal-processed, the presence or absence of a defect and the location of the defect are sequentially detected for all the pixels of the LCD substrate 10, and the inspection result is stored in a storage device (not shown).

When a series of inspections on a plurality of LCD substrates 10 of a predetermined type is completed and an electrical inspection of another type of LCD substrate 10 is newly performed, the existing contact unit 21 is replaced with a new LCD substrate. Replace with a contact unit 21 according to 10. In the case of this replacement, in the case of the present embodiment, the number of wirings between the inspection device 20 and the tester T is much smaller than in the past, so that the number of connection pins (the number of connectors) is extremely small, and the contact unit 21 is extremely easy. Can be replaced. In particular, when the printed circuit board 52 and the TAB 50 are connected via the connection plate 51,
The above exchange work can be performed more easily.

As described above, according to the present embodiment,
A multiplexer 53 for sequentially switching the printed wiring lines 25 is provided on the FPC 26 on the side of the LCD substrate 10 that contacts the drain electrode pad 12.
And the tester T are connected with a smaller number of wires than the number of the printed wires 25, so that the FPC 26 of the contact unit 21 is
Can be simplified and the handling thereof can be facilitated, and the number of FPCs 27 used to connect the inspection apparatus 20 and the tester T can be significantly reduced compared to the conventional case, and the number of connectors on the tester T side can be significantly reduced. T can be reduced in size. In addition, the contact unit 21 can be easily replaced with various LCD substrates 10 with a small number of connectors due to the reduction in the number of FPCs 27 used, and thus the replacement operation can be performed in a short time and the inspection efficiency can be increased.

Further, according to the present embodiment, the flat cable 27 between the FPC 27 and the printed circuit board 52 is significantly simplified by reducing the number of printed wiring after the TAB 50, and the contact unit 21 itself can be moved. Accordingly, when a plurality of LCD substrates 10 are formed on the glass substrate 11, the probe can be brought into contact with the electrode pads 12 and 13 by moving the contact units 21 and 22 while the mounting table is stationary. Therefore, the moving area of the mounting table can be reduced, and the inspection unit can be made more compact. Further, when the TAB 50 and the printed circuit board 52 are connected via the connection plate 51, it is only necessary to exchange the probe 23 to the TAB 50 and exchange the probe 23 corresponding to various LCD substrates 10. And the number of replacement parts can be reduced. Further, even when all of the components from the pin block 24 to the flat cable 27 are replaced, the replacement operation is easy because the whole is compact.

It should be noted that the present invention is not limited to the above embodiment at all, and such an invention is included in the present invention unless departing from the gist of the present invention.

[0023]

As described above, according to the first aspect of the present invention, the size of the tester can be reduced, and the contact unit can be easily replaced with various liquid crystal display substrates. Accordingly, it is possible to provide an inspection apparatus for a substrate for a liquid crystal display, which can increase the inspection efficiency.

According to the second aspect of the present invention, in the first aspect, the contact unit can be replaced more quickly, and the number of replacement parts can be reduced. An inspection device for a liquid crystal display substrate can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of an LCD substrate inspection apparatus according to the present invention, and is an explanatory diagram illustrating a wiring relationship between a contact unit and a tester of the inspection apparatus.

FIG. 2 is a side view showing a main part of a contact unit of the inspection device shown in FIG.

FIG. 3 is a block diagram showing a configuration of a main part of the inspection apparatus shown in FIG.

FIG. 4 is an explanatory diagram showing a wiring relationship of a contact unit of a conventional inspection device.

FIG. 5 is a side view corresponding to FIG. 2, showing the contact unit shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 LCD board 12 Gate electrode pad 13 Drain electrode pad 20 Inspection apparatus 21 Contact unit 24 Printed wiring 25 FPC (Printed wiring board) 51 Connection board (Connector) 53 Multiplexer (Switching circuit) T Tester

Claims (2)

[Claims] A plurality of contact terminals corresponding to a plurality of gate electrodes and a plurality of drain electrodes arranged along a peripheral portion of a substrate for a liquid crystal display; A contact unit having a flexible printed wiring board; connecting each of the printed wiring boards to a tester side; conducting a test terminal to each of the contact terminals which have been brought into contact with each of the electrodes collectively; and a liquid crystal display substrate. In an inspection apparatus for performing an array inspection, a switching circuit for sequentially switching each of the printed wirings is provided to be connected to each of the printed wiring boards on the drain electrode side, and the switching circuit and the tester are arranged based on the number of the printed wirings. An inspection apparatus for a substrate for a liquid crystal display, wherein the inspection is performed with a small number of wires. 2. The apparatus for inspecting a substrate for a liquid crystal display according to claim 1, wherein a connector is provided on a wiring on the tester side of the switching circuit.