WO2006093349A1

WO2006093349A1 - Inspecting apparatus and inspecting method

Info

Publication number: WO2006093349A1
Application number: PCT/JP2006/304668
Authority: WO
Inventors: Masato Ikeda; Shuji Yamaoka; Shogo Ishioka
Original assignee: Oht Inc.
Priority date: 2005-03-04
Filing date: 2006-03-03
Publication date: 2006-09-08
Also published as: JP2006242860A; TW200643411A

Abstract

An inspecting apparatus and an inspecting method for inspecting conformity of an object to be inspected at a high speed are provided. Noncontact inspection is performed by fixing a sensor (1) on an upper section of a liquid crystal panel (glass substrate) (10) i.e. the object to be inspected and floating the object (10) by an air flow. At the time of performing such inspection, a distance between the sensor (1) and the liquid crystal panel (10) is measured by a laser length measurement by a length measuring section (4). Based on the results, air is jetted from an air jetting section (11) also from the senor side, and the distance (gap) between the sensor (1) and the liquid crystal panel (10) is controlled.

Description

Description Inspection apparatus and inspection method Technical Field

The present invention relates to an inspection apparatus and an inspection method for inspecting the quality of pixel electrodes formed on, for example, a liquid crystal panel and a liquid crystal display. Background art

In response to demands for thinner and larger displays such as television receivers and personal computers, liquid crystal display panels with a high pixel count have been developed, and products that use them have been put on the market. For products that employ such thin and large display devices, it is important not only to perform operation tests after product assembly, but also to check for pixel electrode defects in the display alone.

As the inspection method for pixel electrodes, conductive patterns, etc., the so-called pin contact method uses a probe and does not improve the inspection accuracy. Therefore, in a non-contact state via capacitive coupling between the conductor pattern to be inspected and the sensor. Conventionally, a method has been used in which an inspection signal is supplied to an inspection object, and the signal is detected from the inspection object in a non-contact state to conduct a continuity inspection. In order to maintain such a non-contact state, for example, a liquid crystal display substrate inspection apparatus disclosed in Patent Document 1 uses air levitation in a glass substrate inspection apparatus. Patent Document 2 discloses a printed wiring board inspection device that moves a substrate to be inspected to a sensor position by airflow.

On the other hand, the levitation device described in Patent Document 3 moves a planar object with air pressure. It is a stable surface and uses less compressed air. Therefore, it is equipped with an air mixing means that mixes the supplied compressed air with the atmospheric air in the vicinity of the device, and reduces the compressed air by mixing the atmospheric air, and at the same time increases the air flow rate and injects it to the object. It is configured to float up.

Patent Document 1 Japanese Patent Laid-Open No. 1 1 1 1 4 2 8 0 2

Patent Document 2 Japanese Patent Laid-Open No. 2 0 0 2— 1 8 1 8 7 5

Patent Document 3 Japanese Patent Laid-Open No. 2 0 0 4-2 6 2 6 0 8

In the inspection using the non-contact method, the sensor is placed close to the pixel electrode of the liquid crystal display. Therefore, the glass substrate on which the pixel electrode to be inspected is placed is fixed on the stage, and the sensor head is aired. It is necessary to keep the gap between the inspection target and the sensor head constant by floating. In other words, in the non-contact method, it is necessary to determine whether the inspection target is good or not based on a slight level difference in the detection signal. However, in the conventional devices and methods described above, the inspection target and sensor head There is a problem that the gap between the object to be inspected and the sensor head cannot be controlled.

In particular, the inspection apparatus described in Patent Document 1 uses air to reduce the frictional resistance between the substrate to be inspected and the stage, and in the apparatus described in Patent Document 3, air is injected to the bottom of the substrate. When the substrate is levitated by air, compressed air and air in the atmosphere are mixed and jetted to save compressed air. None of the devices controls the gap between the sensor and the test object.

Therefore, the conventional air levitation method requires the adjustment in the z-axis direction (perpendicular to the object to be inspected) for each sensor, resulting in a complicated mechanism for maintaining the gap. Also, since the inertial mass of the sensor head is relatively large, when performing a high-speed scan, it may not be able to follow it and fall into a stop state (crash). Furthermore, adjustment work at the site of use The work is complicated and it is difficult to attach and detach the sensor. Disclosure of the invention

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an inspection apparatus and an inspection method capable of detecting the quality of pixel electrodes on a panel with high accuracy and high speed. That is, it is to provide an inspection apparatus and an inspection method that can follow high-speed scanning.

As a means for achieving this object and solving the above-mentioned problems, for example, the following configuration is provided. That is, the present invention is an inspection apparatus that supplies an inspection signal to an inspection object and inspects the state of the inspection object, and is a first device that generates a gas flow from a first direction with respect to the inspection object. Gas flow generating means, second gas flow generating means for generating a gas flow with respect to the inspection object from a second direction opposite to the first direction, and detecting the inspection signal from the inspection object A sensor, and the sensor detects the inspection signal in a non-contact manner from the inspection object in a state of being floated by the gas flow from the first direction and the gas flow from the second direction, and The quality of the inspection object is identified based on the detected change in the detection signal. For example, the gas flow from the first direction is a gas flow rising toward the inspection object, and the gas flow from the second direction is a gas flow descending toward the inspection object. . Further, for example, the second gas flow generating means is provided in a plurality of regions in the vicinity of the sensor.

For example, it is characterized by further comprising control means for controlling the ejection of the gas flow by the second gas flow generation means so that the sensor is separated from the inspection object by a predetermined distance. Further, for example, the control means individually selects the second gas flow generation means according to the distance between the sensor and the inspection object. Alternatively, the gas flow is ejected.

For example, the control means measures the distance between the sensor and the inspection object based on the interference phase difference between the incident laser light and the reflected laser light on the inspection object, and the first measurement based on the measurement result. It is characterized in that the gas flow is controlled by the gas flow generating means (2).

For example, the gas flow includes at least a gas flow of air, nitrogen, or other inert gas.

For example, the sensor has a configuration in which a portion facing the inspection object protrudes, and a sensor electrode is arranged on the protruding portion, and the inspection object is contactlessly connected through capacitive coupling between the sensor electrode and the inspection object. Further, the above inspection signal is detected.

For example, the apparatus further comprises positioning movement means for positioning and moving the inspection object so as to sequentially scan the inspection object while maintaining the proximity state of the sensor electrode and the inspection object.

As another means for solving the above-described problems, for example, the following configuration is provided. That is, the present invention is an inspection method for supplying an inspection signal to an inspection object and inspecting the state of the inspection object by a sensor,

A gas flow is generated from the direction 1 and a gas flow is also ejected from the second direction facing the first direction toward the inspection target, and the inspection target is floated by the sensor. The inspection signal is detected in a non-contact manner from the inspection object, and the quality of the inspection object is identified based on a change in the detection signal.

For example, the ejection of the gas flow from the second direction is controlled so that the sensor is separated from the inspection object by a predetermined distance. For example, the gas flow from the second direction is ejected from a plurality of regions near the sensor, and the gas flow from the second direction depends on the distance between the sensor and the inspection object. These gas flows are selected individually. Brief Description of Drawings

FIG. 1 is a block diagram showing the overall configuration of an inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cross-sectional configuration when the sensor of the embodiment is cut.

FIG. 3 is a diagram for explaining the position control of the inspection object and the sensor at the time of inspection.

FIG. 4 is a diagram showing an arrangement example of a laser input / output unit and an air jet unit in the sensor.

FIG. 5 is a flowchart showing a control procedure of the distance (gap) between the inspection object and the sensor in the inspection apparatus according to the present embodiment.

FIG. 6 is a diagram showing another arrangement example of the laser input / output unit and the air ejection unit. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. Fig. 1 is a block diagram showing the overall configuration of an inspection apparatus (array test) according to this embodiment. Fig. 1 (a) shows the configuration of signal processing, and Fig. 1 (b) shows the configuration for air control. Each configuration is shown. The inspection target here has, for example, a structure in which a plurality of pixel electrodes and a thin film transistor (TFT) for driving them are arranged in an array (or matrix) on a glass substrate. LCD panel and evening type panel.

In the inspection device shown in Fig. 1 (a), the pixel electrodes are inspected in a non-contact manner. Therefore, the line-shaped sensor 1 is positioned at a position separated from the liquid crystal panel 10 by a predetermined distance in the vertical direction. This sensor 1 has, for example, the same width as the width of the liquid crystal panel 10 and a one-dimensional line for determining the presence / absence of disconnection of the pixel electrode on the liquid crystal panel 10 by a non-contact method using a sensor circuit described later. It is a sensor. This inspection device inspects the quality of the pixel electrodes of the liquid crystal panel 10 based on the output from the sensor 1. Further, a pixel voltage supply unit 13 is connected to the liquid crystal panel 10, thereby supplying signals necessary for pixel inspection to individual pixel electrodes.

The sensor 1 includes a plurality of sensor substrates 5 a and 5 b arranged regularly as shown in FIG. 1 (a). That is, in the sensor 1, the sensor substrates 5a and 5b are arranged in a line, and they are alternately juxtaposed at a constant pitch width on the spacer 33 having a predetermined thickness. This is a one-dimensional line sensor configured to have almost the same width as the inspection target part of the liquid crystal panel 10, and the tip part of the sensor board 5 a, 5 b on the spacer 33 side is arranged oppositely. The other sensor substrate is arranged in such a manner that a part thereof overlaps with the tip end portion in the row direction.

In this way, the tip end portions of the sensor boards 5 a and 5 b partially overlap with the opposing sensor boards, so that the sensor circuits 3 1 ( Since the sensor electrodes of each other also overlap each other in the column direction, depending on the relative positional relationship between the pixel electrodes of the liquid crystal panel 10 and the sensor circuit, two sensor circuits More specifically, since the sensor electrode 3 1) can simultaneously detect signals, the pixel electrode can be reliably judged as good or bad.

The pixel signal detected by the sensor circuit 31 arranged on each sensor board 5a, 5b is input to the signal processing unit 3. The signal processing unit 3 performs processing such as amplification, multiplexing, waveform shaping, and AZD conversion, for example. And the control part 6 Compares the signal level processed by the signal processing unit 3 with a preset reference value and determines whether or not it is within the reference range. The judgment result is sent to the display unit 9.

Further, the sensor 1 outputs a laser beam 18 a (for example, a pulsed laser) toward the liquid crystal panel 10 to be inspected as shown in FIG. Laser input / output unit 2 consisting of 1 8 and a light receiving unit 1 9 (for example, a photomultiplier tube) that receives the laser beam 19 9 (reflected beam) reflected by the liquid crystal panel 10 and returning again Have Further, based on the output laser beam 18 a and the reflected laser beam 19 a, the length measuring unit 4 that measures the distance to the inspection target (liquid crystal panel 10), and the length measuring unit 4 as described later. An air control unit 1 2 that receives the measurement result, and an air injection unit 1 1 that ejects air (downward airflow) from the sensor 1 toward the inspection object in accordance with the control from the air control unit 12 .

In the following description, the gas ejected toward the inspection object is described as an example of air. However, the present invention is not limited to this, and for example, a gas flow caused by nitrogen or other inert gas may be used. Good.

In order to control the entire inspection apparatus, the control unit 6 is composed of, for example, a micro-port sensor, and comprehensively controls a predetermined inspection sequence. The control unit 6 has a ROM 7 and a RAM 8, and the ROM 7 stores a control procedure including an inspection procedure as a computer program, for example, and the RAM temporarily stores, for example, control data and inspection data. Used as a work area to store automatically.

The display unit 9 is made up of, for example, a CRT, a liquid crystal display, and the like. If the inspection object (pixel electrode of the liquid crystal panel) that is the determination result sent from the control unit 6 is satisfactory, the position information of the sensor 1 is inspected. Visually display in a format that can be easily understood. If there is an abnormality in the position of sensor 1, this is indicated, and the pixel electrode etc. If there is a defect, the position of the electrode on the panel substrate is also displayed by, for example, the electrode number and coordinates. In addition, the display of the inspection result is not limited to the visual display, and may be output in a format such as sound. Also, visual display and audio may be mixed.

The drive unit 16 receives the control signal from the control unit 6 and moves the entire liquid crystal panel 10 in a predetermined direction at a predetermined speed. As a result, the sensor 1 sequentially scans the arrayed pixel electrodes on the liquid crystal panel 10 in a non-contact state. Specifically, as will be described later, the drive unit 16 moves the liquid crystal panel 10 that has been levitated by the air flow from the bottom to the top in a predetermined direction on the order. For this reason, three-dimensional position control is possible by four-axis control of XYZ0 angles, and the liquid crystal panel 10 is positioned at a reference position before inspection, which is separated from the sensor position by a certain distance.

Next, the sensor unit in the inspection apparatus according to the present embodiment will be described. FIG. 2 shows a cross-sectional configuration when the sensor 1 is cut along the two-dot chain line A—A ′ in FIG. The sensor substrates 5 a and 5 b are made of glass having a predetermined thickness t 2 (for example, 0.5 mm) with a size of, for example, 2500 mm × 100 mm, and approximately at the center thereof The structure is bent (bent) into an S-shape with a loose cross section. A sensor circuit 31 having a sensor electrode 20 is disposed on the upper surface end of the sensor substrate 5a, 5b opposite to the inspection target. The substrate material of the sensor substrates 5a and 5b is not limited to glass, and may be made of plastic or quartz, for example.

The liquid crystal panel 10 to be inspected is composed of a glass substrate and a plurality of pixel electrodes 15 formed on the surface thereof as shown in FIG. 2, and is arranged close to the pixel electrodes 15. The sensor electrode 20 of the sensor 1 is connected to the pixel electrode 15 of the liquid crystal panel 10 from the pixel voltage supply unit 13 shown in FIG. Signal potential (pixel voltage) is detected in a non-contact manner.

In the inspection apparatus according to the present embodiment, since the liquid crystal panel is inspected in a non-contact manner using the sensor 1, the distance d between the sensor electrode 20 and the pixel electrode 15 on the liquid crystal panel 10 is set to For example, 50 or less. For this reason, the spacer 3 3 provided on the substrate 24 (having a thickness tl of 1.0 mm, for example) has a structure in which the central portion of the sensor 1 protrudes more vertically than the substrate 24. Yes. Also, the sensor electrode 20 constituting the sensor circuit 31 is connected to the gate terminal (G) of the CMO S element (MOS type field effect transistor) formed on the sensor substrates 5a and 5b, for example. It consists of a conductor film (for example, IT * film) having a predetermined area. The substrate 24 is made of a metal such as aluminum.

Next, distance control (gap control) between the inspection object and the sensor in the inspection apparatus according to the present embodiment will be described. FIG. 3 is a diagram for explaining the positional control and positional relationship between the inspection object and the sensor at the time of inspection. As shown in FIG. 3, the sensor 1 is fixedly disposed at a predetermined position above the liquid crystal panel 10 to be inspected in a non-contact state with the liquid crystal panel 10, and the air supply unit 5 is disposed below the liquid crystal panel 10. Serve 0. An air flow (upward flow indicated by an upward arrow in the figure) is generated from the air supply unit 50 toward the liquid crystal panel 10, and the liquid crystal panel 10 receives the air flow and receives a predetermined distance. Only emerged. That is, the air supply section 50 has a large number of holes (not shown) over the entire upper surface, and the air flow ejected from these holes is blown evenly over the entire inspection target, The liquid crystal panel 10 is lifted by the pressure of the air flow.

Fig. 4 shows an example of the arrangement of the laser input / output unit and air ejection unit in the sensor. FIG. 4 shows the state when the sensor 1 is viewed from the liquid crystal panel 10 side. As shown in Figure 3 and Figure 4, the sensor 2 substrate 2 4 On the side where the substrate 5 a, 5 b is arranged, the laser input / output units 2 a to 2 z and the air jet are ejected at regular intervals at the end of the substrate 24 near the sensor substrates 5 a, 5 b. Parts 1 1 a to 1 1 z are arranged. Each laser input / output unit 2a to 2z outputs laser light from its output unit 18 (see Fig. 1 (b)) toward the liquid crystal panel 10 during inspection, and receives the reflected laser beam. 1 Receive in 9. Then, the length measuring unit 4 determines the distance between the sensor electrode 20 and the pixel electrode 15 on the liquid crystal panel 10 based on the interference phase difference between the laser beam incident on the liquid crystal panel 10 and the reflected laser beam. Measure d.

These measurement results are sent as distance (gap) data from the length measuring section 4 to the gear control section 12. Based on this distance data, the air control unit 1 2 determines which of the sensor substrates 5 a and 5 b has an abnormality in the distance d between the sensor electrode 20 and the pixel electrode 15. In other words, it is determined whether the distance is too close or too far from the predetermined distance determined in advance. Then, the air control unit 12 controls the air ejection units 1 1 a to 1 1 z individually according to the determination result.

That is, by adjusting the air ejection amount from each of the air ejection portions 1 1 a to 1 1 z based on the actually measured distance (gap) d between the sensor electrode 20 and the pixel electrode 15, Feed pack control is performed so that the distance d between the sensor electrode and the pixel electrode of the liquid crystal panel is maintained at a predetermined value (a constant value). For example, when the distance d between the sensor electrode and the pixel electrode is smaller than a predetermined value in the vicinity of the laser input / output units 2a to 2c, the air control unit 12 It is determined that the sensor 1 is too close, and a predetermined amount of air (downflow) is ejected from the air ejection portions 1 1 a to l 1 c. The liquid crystal panel 10 that has received the pressure of the blown air is pushed to a position where the pressure and the pressure of the air flow from the air supply unit 50 are balanced. Repeat this distance (gap) d measurement and air ejection FIG. 5 shows a control procedure for the distance (gap) between the inspection target and the sensor in the inspection apparatus according to the present embodiment. It is a flowchart. In step S 1 1 in Fig. 5, the length measuring unit 4 uses a sensor electrode and a liquid crystal panel based on the interference phase difference between the incident laser beam and the reflected laser beam from all laser input / output units 2a to 2z. Measure the distance d between the upper pixel electrodes. In the subsequent step S 13, the measured value is compared with a predetermined value to determine whether the distance (gap) d between the sensor electrode and the pixel electrode is within an appropriate range.

If the distance (gap) d is an appropriate value as a result of the determination in step S 1 3, the air amount from the air ejection sections 1 1 a to 1 1 z is maintained at the current value in step S 1 4. . If it is determined that the distance (gap) d is small, it is determined that the liquid crystal panel 10 is too close to the sensor 1. In step S15, the sensor 1 is too close to the liquid crystal panel 10 In step S16, select the air outlet corresponding to the identified location. In step S 17, the air ejection amount from the selected air ejection section is increased.

On the other hand, if it is determined that the distance (gap) d is large, the liquid crystal panel 1 0 is too far from the sensor 1, so in step S 25, the sensor 1 is too far from the liquid crystal panel 10. And the air blowout part corresponding to the identified part is selected in step S26. Then, in the following step S27, the air ejection amount from the selected air ejection section is reduced.

As a result of the above control, increase or decrease the air ejection amount from the air ejection section 1 1 a to 1 1 z to increase or decrease according to the amount of air. The pressure due to the air flow from the air supply unit 50 becomes inferior or prevailing by the reduced pressure. As a result, the liquid crystal panel 10 is separated from or closer to the sensor 1 side. In this way, by adjusting the air ejection amount from each of the air ejection sections 1 1 a to 1 1 z, the distance d between the sensor electrode 20 and the pixel electrode 15 of the liquid crystal panel 10 becomes constant. By performing feedback control between the measurement unit 4 and the air control unit 1 2, the distance between the liquid crystal panel and the sensor is kept constant.

At the time of inspection, the liquid crystal panel 10 is moved, for example, in the direction of the arrow in FIG. Then, the sensor 1 sequentially scans the pixel electrodes 15 on the liquid crystal panel 10, thereby checking the quality continuously. In step S 3 0, the end of the inspection is determined. If all the pixels have not been inspected, the process returns to step S 1 1 and the distance d between the sensor electrode and the pixel electrode is measured again. Then, the air ejection control is continued as described above. When the inspection is completed, measurement and air control are also completed.

As described above, when a sensor is fixed to the upper part of the liquid crystal panel (glass substrate) to be inspected and the inspection object is floated by airflow to perform non-contact inspection, the sensor and liquid crystal panel are measured by laser measurement. By measuring the distance between the sensors, air is also blown from the sensor side based on the result, and the gap between the sensor and the liquid crystal panel is controlled, eliminating the need for on-site adjustments. It becomes easy to attach and detach.

In addition, air flow from both sides of the inspection target (glass substrate) not only facilitates control of the distance between the sensor and the inspection target, but also provides high tracking capability for high-speed operation for scanning and inspection of the inspection target. In addition, damage to the liquid crystal panel can be easily avoided. Furthermore, since the distance between the sensor and the object to be inspected can be controlled to the minimum, the sensitivity and resolution of the sensor are improved, and the pixel voltage of the pixel electrode can be reliably detected in a non-contact manner. In addition, by providing a length measurement unit and air control unit corresponding to the sensor substrate of the sensor, it is possible to control the distance between the sensor and the inspection target at the same time or individually at multiple locations of the sensor, and it is necessary to adjust the Z axis for each sensor Disappears.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example

The arrangement of the laser input / output part and the air ejection part in the sensor is not limited to the example shown in FIG. 4, but the laser input / output part is placed on both sides of the tip of each sensor board 5a, 5b as shown in FIG. May be provided. Industrial applicability

According to the present invention, the gap control between the inspection target and the sensor head can be easily performed with high accuracy, and the quality of the inspection target can be detected accurately and at high speed. In addition, the sensor is easy to attach and detach because of its simple mechanism.

Claims

The scope of the claims

1. An inspection device that supplies an inspection signal to an inspection object and inspects the state of the inspection object,

First gas flow generating means for generating a gas flow from a first direction with respect to the inspection object;

A second gas flow generating means for generating a gas flow with respect to the inspection object from a second direction opposite to the first direction;

A sensor for detecting the inspection signal from the inspection object, wherein the sensor is less than the inspection object in a state of being floated by the gas flow from the first direction and the gas flow from the second direction. An inspection apparatus, wherein the inspection signal is detected by contact, and the quality of the inspection target is identified based on a change in the detected detection signal.

2. The gas flow from the first direction is a gas flow rising toward the inspection object, and the gas flow from the second direction is a gas flow descending toward the inspection object. The inspection apparatus according to claim 1.

3. The inspection apparatus according to claim 2, wherein the second gas flow generating means is provided in a plurality of regions near the sensor.

4. The inspection apparatus according to claim 3, further comprising a control unit that controls ejection of the gas flow by the second gas flow generation unit so that the sensor is separated from the inspection target by a predetermined distance.

5. The control means selects the second gas flow generation means individually according to the distance between the sensor and the inspection object, and ejects the gas flow. Inspection equipment.

6. The control means measures the distance between the sensor and the inspection object based on the interference phase difference between the incident laser light and the reflected laser light on the inspection object, and 6. The inspection apparatus according to claim 5, wherein ejection control of the gas flow by the second gas flow generation means is performed based on the measurement result.

7. The inspection apparatus according to any one of claims 1 to 6, wherein the gas flow includes at least a gas flow of air, nitrogen, or other inert gas.

8. The sensor has a configuration in which a portion facing the inspection object protrudes and a sensor electrode is disposed on the protruding portion, and the inspection object is contactlessly connected through capacitive coupling between the sensor electrode and the inspection object. The inspection apparatus according to claim 1, further comprising detecting the inspection signal.

9. The apparatus according to claim 1, further comprising positioning moving means for positioning and moving the inspection object so as to sequentially scan the inspection object while maintaining a proximity state of the sensor electrode and the inspection object. The inspection device according to any one of the above.

1 0. An inspection method in which an inspection signal is supplied to an inspection object and the state of the inspection object is inspected by a sensor,

In a state in which a gas flow is generated from the first direction of the inspection object and a gas flow is ejected from the second direction opposite to the first direction toward the inspection object, and the inspection object is floated An inspection method, wherein the inspection signal is detected by the sensor in a non-contact manner from the inspection object, and the quality of the inspection object is identified based on a change in the detection signal.

11. The inspection method according to claim 10, wherein ejection of a gas flow from the second direction is controlled so that the sensor is separated from the inspection object by a predetermined distance.

1 2. The gas flow from the second direction is ejected from a plurality of areas near the sensor, and the gas flow from the second direction is individually selected according to the distance between the sensor and the inspection object. Claim 1. The inspection according to claim 1 Method.