JP2006242860A - Inspection device and inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection device and an inspection method capable of inspecting at high speed the quality of an inspection object. <P>SOLUTION: When performing noncontact inspection by fixing a sensor 1 on the upper part of a liquid crystal panel (glass substrate)10 which is the inspection object, and by floating the inspection object 10 by airflow, the distance between the sensor 1 and the liquid crystal panel 10 is measured by laser length measurement by a length measuring part 4, and air is blown out by an air blowout part 11 also from the sensor side based on the result, to thereby control the interval (gap) between the sensor 1 and the liquid crystal panel 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  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.

  With the demand 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 are on the market. In a product employing such a thin and large display device, not only an operation test after the product is assembled, but also an inspection for determining the presence or absence of a pixel electrode defect in the display unit is important.

  As a method for inspecting pixel electrodes and conductive patterns, the so-called pin contact method uses a probe, so the inspection accuracy does not improve. Therefore, inspection is performed in a non-contact state through capacitive coupling between the conductor pattern to be inspected and the sensor. Conventionally, a method of supplying a test signal to an object, detecting the signal from the test object in a non-contact state, and performing a continuity test has been used. In order to maintain such a non-contact state, for example, in a liquid crystal display substrate inspection apparatus disclosed in Patent Document 1, air levitation is used in a glass substrate inspection apparatus. Patent Document 2 discloses a printed wiring board inspection apparatus 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 stably levitates a planar object with the pressure of air and reduces the amount of compressed air consumption. 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 the compressed air is decompressed by mixing the atmospheric air, and at the same time the air flow rate is increased and injected to the object. It is configured to float up.

JP-A-11-142802 JP 2002-181875 A JP 2004-262608 A

  In the inspection using the non-contact method, in order to bring the sensor close to the pixel electrode of the liquid crystal display, the glass substrate on which the pixel electrode to be inspected is arranged is fixed on the stage, and the sensor head is floated on the air. Therefore, it is necessary to maintain a constant gap between the inspection target and the sensor head. That is, in the non-contact method, it is necessary to determine whether the inspection target is good or not based on a slight level difference of the detection signal, but the conventional apparatus and method described above cannot sufficiently bring the inspection target and the sensor head close enough. In addition, there is a problem that it is impossible to control the gap between the inspection target and the sensor head.

  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. In the apparatus described in Patent Document 3, the substrate is ejected by air jetting to the lower part of the substrate. When air is floated with air, compressed air is saved by mixing and jetting compressed air and air in the atmosphere. None of the devices perform gap control between the sensor and the inspection object.

  Therefore, the conventional air levitation method requires 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. Further, since the inertial mass of the sensor head is relatively large, when high-speed scanning is performed, there is a possibility that the sensor head cannot follow it and fall into a stopped state (crash). Furthermore, there is a problem that adjustment work at the site of use becomes complicated and it is difficult to attach and detach the sensor.

  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 device that supplies an inspection signal to an inspection object and inspects the state of the inspection object, and is a first gas that generates a gas flow from a first direction with respect to the inspection object. A flow generating means, 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, and a sensor for detecting the inspection signal from the inspection object; 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. The quality of the inspection object is identified based on the change in the detected 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 falling toward the inspection object. . Further, for example, the second gas flow generation 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 generating means so that the sensor is separated from the inspection object by a predetermined distance. Further, for example, 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.

  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 based on the measurement result, The gas flow jetting control is performed by the gas flow generating means.

  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 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 problem, for example, the following configuration is provided. That is, the present invention is 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, and a gas flow is generated from a first direction of the inspection object and the first The gas flow is also ejected from the second direction opposite to the inspection object toward the inspection object, and the inspection signal is detected in a non-contact manner from the inspection object by the sensor in a state where the inspection object is floated. 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. In addition, 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 is individually selected according to the distance between the sensor and the inspection object. It is characterized by doing.

  According to the present invention, the gap control between the inspection target and the sensor head can be performed easily and with high accuracy, and the quality of the inspection target can be detected with high accuracy and at high speed. In addition, since the mechanism is simple, the sensor can be easily attached and detached.

  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 tester) according to the present embodiment. FIG. 1 (a) shows a signal processing configuration, and FIG. 1 (b) shows a configuration for air control. Respectively. The inspection object here is, for example, a liquid crystal display panel having a structure in which a plurality of pixel electrodes and thin film transistors (TFTs) for driving them are arranged in an array (or matrix) on a glass substrate Or a touch panel.

  In the inspection apparatus shown in FIG. 1A, the line-shaped sensor 1 is positioned at a position spaced apart from the liquid crystal panel 10 by a predetermined distance in order to inspect the pixel electrodes and the like in a non-contact manner. The sensor 1 is, for example, a one-dimensional line sensor that has the same width as the liquid crystal panel 10 and determines whether or not a pixel electrode on the liquid crystal panel 10 is disconnected by a non-contact method using a sensor circuit or the like described later. . The inspection apparatus inspects the quality of the pixel electrodes of the liquid crystal panel 10 based on the output from the sensor 1. In addition, 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 5a and 5b regularly arranged as shown in FIG. That is, the sensor 1 arranges the sensor substrates 5a and 5b in a line shape, and alternately arranges them on the spacers 33 having a predetermined thickness with a constant pitch width, and the inspection target of the liquid crystal panel 10 as a whole. This is a one-dimensional line sensor configured to have substantially the same width as the portion, and the tip end portion on the spacer 33 side of the sensor substrates 5a and 5b is in the column direction with the tip end portion of the other sensor substrate arranged opposite to the sensor substrate 5a, 5b. The arrangement configuration in which a part overlaps each other is taken.

  Thus, the sensor circuit 31 (refer FIG. 2) distribute | arranged to each sensor board | substrate 5a, 5b has it because the front-end edge part of each sensor board | substrate 5a, 5b has taken the structure which overlaps with the opposing sensor board | substrate. Since the sensor electrodes also overlap with each other in the column direction, depending on the relative positional relationship between the pixel electrode of the liquid crystal panel 10 and the sensor circuit, two sensor circuits (specifically, the sensor electrode 31) are used for one pixel electrode. Since signals can be detected at the same time, it is possible to reliably determine whether the pixel electrode is good or bad.

  Pixel signals detected by the sensor circuits 31 arranged on the sensor substrates 5 a and 5 b are input to the signal processing unit 3. The signal processing unit 3 performs processing such as amplification, multiplexing, waveform shaping, and A / D conversion, for example. Then, the control unit 6 compares the signal level processed by the signal processing unit 3 with a preset reference value, and determines whether it is within the reference range. The determination result is sent to the display unit 9.

  Further, the sensor 1 outputs a laser beam 18a (for example, a pulsed laser) toward the liquid crystal panel 10 to be inspected as shown in FIG. The laser input / output unit 2 includes a light receiving unit 19 (for example, a photomultiplier tube) that receives a laser beam 19a (reflected beam) that is reflected by the panel 10 and returns again. Further, based on the output laser beam 18a and the reflected laser beam 19a, the length measuring unit 4 that measures the distance to the inspection object (liquid crystal panel 10) and the length measurement result are received from the length measuring unit 4 as will be described later. In accordance with control from the air control unit 12, the air control unit 12 includes an air ejection unit 11 that ejects air (downward airflow) from the sensor 1 toward the inspection target.

  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. For example, a gas flow using 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 microprocessor and comprehensively controls a predetermined inspection sequence. The control unit 6 includes a ROM 7 and a RAM 8. 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.

  The display unit 9 includes, for example, a CRT, a liquid crystal display, and the like, and an inspector indicates whether the inspection target (pixel electrode of the liquid crystal panel) is the determination result sent from the control unit 6 or the positional information of the sensor 1. Visually display in an easily understandable format. If there is an abnormality in the position of the sensor 1, that fact is displayed, and if there is a defect in the pixel electrode or the like, the position of the electrode on the panel substrate is also displayed by, for example, an electrode number or coordinates. The display of the inspection result is not limited to the visible display, and may be output in a format such as sound. Further, visual display and sound 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 is levitated by an air flow from below to above in a predetermined direction on the order of μm. Therefore, three-dimensional position control is possible by four-axis control of the XYZCθ angle, 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 ′ of FIG. The sensor substrates 5a and 5b are made of glass having a size of, for example, 250 mm × 100 mm and a predetermined thickness t2 (for example, 0.5 mm), and are bent into an S-shape having a loose cross section at a substantially central portion ( It has a flexible structure. And the sensor circuit 31 which has the sensor electrode 20 is distribute | arranged to the upper surface edge part of the side facing the test object of sensor board | substrate 5a, 5b. The substrate material of the sensor substrates 5a and 5b is not limited to glass, and may be made of, for example, plastic or quartz.

  The liquid crystal panel 10 to be inspected includes a glass substrate and a plurality of pixel electrodes 15 formed on the surface of the glass substrate as shown in FIG. The electrode 20 detects the signal potential (pixel voltage) applied to the pixel electrode 15 of the liquid crystal panel 10 from the pixel voltage supply unit 13 shown in FIG. 1 in a non-contact manner.

  In the inspection apparatus according to the present embodiment, since the sensor 1 is used to inspect the liquid crystal panel in a non-contact manner, the distance d between the sensor electrode 20 and the pixel electrode 15 on the liquid crystal panel 10 is, for example, 50 μm or less. To do. Therefore, the spacer 33 (having a thickness t1 of, for example, 1.0 mm) provided on the substrate 24 has a structure in which the central portion of the sensor 1 protrudes more vertically than the substrate 24. The sensor electrode 20 constituting the sensor circuit 31 is connected to the gate terminal (G) of a CMOS element (MOS type field effect transistor) formed on the sensor substrates 5a and 5b, for example, and has a predetermined area. It consists of a conductive film (for example, an ITO film). The substrate 24 is made of a metal such as aluminum.

  Next, distance control (gap control) between the inspection target 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 50 is disposed below the liquid crystal panel 10. . 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 is lifted by a predetermined distance in response to the air flow. It becomes. That is, the air supply unit 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 object to be inspected. The liquid crystal panel 10 is floated by the pressure generated by the flow.

  FIG. 4 shows an arrangement example of the laser input / output unit and the air ejection unit in the sensor. FIG. 4 shows a state when the sensor 1 is viewed from the liquid crystal panel 10 side. As shown in FIGS. 3 and 4, on the side of the substrate 1 of the sensor 1 where the sensor substrates 5a and 5b are disposed, lasers are provided at regular intervals near the sensor substrates 5a and 5b and at the end of the substrate 24. Input / output parts 2a to 2z and air ejection parts 11a to 11z are arranged. Each of the laser input / output units 2a to 2z outputs laser light from the output unit 18 (see FIG. 1B) toward the liquid crystal panel 10 and receives the reflected laser beam by the light receiving unit 19 during inspection. Then, the length measuring unit 4 measures the distance d between the sensor electrode 20 and the pixel electrode 15 on the liquid crystal panel 10 based on the interference phase difference between the incident laser light and the reflected laser light on the liquid crystal panel 10.

  These measurement results are sent as distance (gap) data from the length measurement unit 4 to the air control unit 12. Based on the distance data, the air control unit 12 determines in which of the sensor substrates 5a and 5b the distance d between the sensor electrode 20 and the pixel electrode 15 is abnormal, that is, predetermined. It is determined whether the distance is too close or more than a predetermined distance. And the air control part 12 controls the air ejection parts 11a-11z separately according to the determination result.

  That is, the sensor electrode and the pixel electrode of the liquid crystal panel are adjusted by adjusting the air ejection amount from each of the air ejection portions 11a to 11z based on the actually measured distance (gap) d between the sensor electrode 20 and the pixel electrode 15. Feedback control is performed so that the distance d 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 indicates that the liquid crystal panel 10 is too close to the sensor 1 at that location. Therefore, a predetermined amount of air (downflow) is ejected from the air ejection portions 11a to 11c. The liquid crystal panel 10 that has received the pressure by the blown air is pushed to a position where the pressure and the pressure by the air flow from the air supply unit 50 are balanced. By repeating such measurement of the distance (gap) d and air ejection, the distance d between the sensor electrode and the pixel electrode is controlled to be a predetermined value.

  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. In step S11 of FIG. 5, the length measuring unit 4 determines the distance between the sensor electrode and the pixel electrode on the liquid crystal panel based on the interference phase difference between the incident laser beam and the reflected laser beam from all the laser input / output units 2a to 2z. The distance d is measured. In subsequent step S13, 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 S13, the air amount from the air ejection portions 11a to 11z is maintained at the current value in step S14. 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, and in step S 15, the part of the sensor 1 that is too close to the liquid crystal panel 10 is specified. In subsequent step S16, an air ejection portion corresponding to the identified location is selected. In step S17, the air ejection amount from the selected air ejection section is increased.

  On the other hand, when it is determined that the distance (gap) d is large, the liquid crystal panel 10 is too far from the sensor 1, and therefore, in step S <b> 25, the part of the sensor 1 that is too far from the liquid crystal panel 10 is specified. In step S26, an air ejection portion corresponding to the identified location is selected. In subsequent step S27, the air ejection amount from the selected air ejection section is reduced.

  As a result of the above control, by increasing or decreasing the air ejection amount from the air ejection portions 11a to 11z, the air flow from the air supply unit 50 is increased or decreased according to the air amount. Pressure is inferior or prevailing. As a result, the liquid crystal panel 10 is separated from or close to the sensor 1 side. Thus, the length measuring unit 4 and the air are adjusted so that the distance d between the sensor electrode 20 and the pixel electrode 15 of the liquid crystal panel 10 is constant by adjusting the air ejection amount from each of the air ejection units 11a to 11z. By performing feedback control between the control units 12, the distance between the liquid crystal panel and the sensor is maintained constant.

  At the time of inspection, the liquid crystal panel 10 is moved in the direction of the arrow in FIG. 1, for example. Then, the sensor 1 sequentially scans the pixel electrodes 15 on the liquid crystal panel 10 to inspect the quality continuously. In step S30, the end of the inspection is determined. If all the pixels have not been inspected, the process returns to step S11, and the distance d between the sensor electrode and the pixel electrode is measured again. Continue jetting control. When the inspection is finished, the measurement and the air control are also finished.

  As described above, when a sensor is fixed to the upper part of a liquid crystal panel (glass substrate) to be inspected, and the inspection object is floated by airflow to perform a non-contact inspection, the distance between the sensor and the liquid crystal panel is measured by laser length measurement. By controlling the gap between the sensor and the liquid crystal panel by ejecting air from the sensor side based on the measurement result, adjustment on the site is not necessary, and the sensor can be attached and detached accordingly. It becomes easy.

  In addition, air flow from both sides of the inspection target (glass substrate) not only facilitates the control of the distance between the sensor and the inspection target, but also improves the follow-up capability at high speed operation for scanning and inspection of the inspection target. Moreover, damage to the liquid crystal panel can be easily avoided. Furthermore, since the distance between the sensor and the inspection object 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 by a non-contact method.

  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 object simultaneously or individually at a plurality of locations of the sensor, and it is necessary to adjust the z axis for each sensor. Disappear.

  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 unit and the air ejection unit in the sensor is not limited to the example shown in FIG. 4, and the laser input / output unit is provided on both sides of the tip of each sensor substrate 5a, 5b as shown in FIG. It's okay.

It is a block diagram which shows the whole structure of the test | inspection apparatus which concerns on the example of embodiment of this invention. It is a figure which shows the cross-sectional structure when the sensor of the embodiment is cut. It is a figure for demonstrating the position control of a test object and a sensor at the time of a test | inspection. It is a figure which shows the example of arrangement | positioning of the laser input / output part and air ejection part in a sensor. It is a flowchart which shows the control procedure of the distance (gap) between the test object and the sensor in the test | inspection apparatus which concerns on this Example. It is a figure which shows the other example of arrangement | positioning of a laser input / output part and an air ejection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor 2 Laser input / output part 3 Signal processing part 4 Length measuring part 5a, 5b Sensor board 6 Control part 7 ROM
8 RAM
DESCRIPTION OF SYMBOLS 9 Display part 10 Liquid crystal panel 11 Air ejection part 12 Air control part 13 Pixel voltage supply part 15 Pixel electrode 16 Drive part 18a, 19a Laser beam 20 Sensor electrode 24 Board | substrate 31 Sensor circuit 33 Spacer 50 Air supply part

Claims (12)

An inspection apparatus for supplying an inspection signal to an inspection object and inspecting 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;
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,
The sensor detects the inspection signal in a non-contact manner from the inspection object in a state of floating by the gas flow from the first direction and the gas flow from the second direction, and the detected detection signal An inspection apparatus for identifying whether the inspection object is good or bad based on the change of the inspection object. 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 1. The inspection apparatus according to claim 2, wherein the second gas flow generating means is provided in a plurality of regions near the sensor. 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. The inspection apparatus according to claim 4, wherein the control unit individually selects the second gas flow generation unit according to a distance between the sensor and the inspection target and ejects the gas flow. . 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 based on the measurement result, the second 6. The inspection apparatus according to claim 5, wherein ejection control of the gas flow is performed by the gas flow generating means. The inspection apparatus according to claim 1, wherein the gas flow includes at least a gas flow of air, nitrogen, or other inert gas. 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 sensor electrode and the inspection object are contacted through capacitive coupling between the sensor electrode and the inspection object in a non-contact manner. The inspection apparatus according to claim 1, wherein an inspection signal is detected. 9. The apparatus according to claim 1, further comprising positioning movement means for positioning and moving the inspection object so as to sequentially scan the inspection object while maintaining a proximity state between the sensor electrode and the inspection object. The inspection device described. An inspection method for supplying an inspection signal to an inspection object and inspecting the state of the inspection object with a sensor,
In a state where 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. The inspection method according to claim 10, wherein the ejection of the gas flow from the second direction is controlled so that the sensor is separated from the inspection target by a predetermined distance. 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 is individually selected according to the distance between the sensor and the inspection object. The inspection method according to claim 11.

Images