JPH08229477A - Method for correcting coating position in paste coating device - Google Patents

Abstract

PURPOSE: To provide a method for correcting a coating position in a paste coating device wherein paste can be precisely applied to a spot where coating is applied. CONSTITUTION: Individual spots, to which coating is to be applied, on a TFT array base board which are positioned at a positioning part 1 are taken by, for example, a monitor camera 7 and a central position of the spot to be coated which has been taken is determined by a visual device 8 and coating positions to be coated by means of a coating mechanism 6 are individually corrected so as to reduce the displacement between the central position and a reference position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste applying method in a silver paste applying apparatus used for manufacturing a liquid crystal display device, for example.

[0002]

2. Description of the Related Art As a liquid crystal display device, a TFT (thin fil
Those using an array substrate or the like are known. For example, in a TFT array substrate, transfer electrodes for energizing the respective electrodes are formed by applying silver paste to the application target portion (transfer pad) formed on the TFT array substrate.

In applying the silver paste, after the TFT array substrate to be processed is mechanically positioned and held,
A positioning mark formed at a predetermined position on the substrate is photographed by a monitor camera, and the displacement amount (displacement amount) of the TFT array substrate is obtained by comparing this with a predetermined reference position to reduce the displacement amount. As described above, it is common to correct the coordinate data of the control mechanism that controls the relative position between the application mechanism and the application target location.

The positioning mark is provided on the TFT array substrate because of the factors such as the cutting accuracy of the substrate, the printing position accuracy of the pattern with respect to the outer shape of the substrate, and the repeatability of the positioning mechanism. This is because the target location may vary. However, since the positioning mark and the application target portion are made on the same screen, there is no variation in their positional relationship. Therefore, conventionally, if the displacement amount of the positioning mark is obtained after the positioning based on the outer shape reference, it is possible to know from the displacement amount how much the pattern of the application target portion on the substrate is relatively displaced from the reference position. The coordinate data is corrected.

As a technique for applying such a silver paste, as disclosed in Japanese Patent Application Laid-Open No. 2-137339, a technique for obtaining the displacement amount of the substrate from the result of imaging the positioning marks with two sets of monitor cameras, or As disclosed in Japanese Patent Application Laid-Open No. 1-122127, there is known a technique in which a monitor camera mounted on a paste application head captures an image of a positioning mark and similarly obtains a displacement amount of a substrate. It should be noted that these techniques include an illuminating device for illuminating the positioning mark by the monitor camera, and therefore the device configuration is slightly complicated.

[0006]

As described above, the conventional method for correcting the coating position is a method for shifting the coordinate data of the control mechanism based on the displacement amount of the positioning mark, and as a result, all the coating target points are applied. The coating position corresponding to is uniformly corrected. However, in the conventional correction method, if there is a rotation deviation, for example, the correction error may have a stronger influence as the distance from the coordinate origin increases, and all the coating positions may not be corrected in the correct direction. Also, it is not possible to confirm whether the corrected individual coating positions are really predetermined positions. Therefore, there is a case where the silver paste cannot be applied correctly to all the application target portions, and there is a problem that the yield of the TFT array substrate cannot be improved.

In view of the above problems, an object of the present invention is to provide a correction method for accurately applying paste to all of a plurality of application target portions.

[0008]

A method of correcting a coating position in a paste coating apparatus according to the present invention which solves the above-mentioned problems is described below.
Positioning means for positioning the substrate to be processed at a predetermined portion, a coating mechanism for coating the paste on each of the plurality of positioned coating target portions on the substrate, and corresponding to the coating mechanism and individual coating target portions In a paste coating apparatus having a control mechanism for controlling a relative position with respect to a coating position to be coated
And a second step of detecting a displacement amount between the imaged application target portion and a predetermined reference position, and a third step of correcting the relative position so as to reduce the detected displacement amount. And a step of performing the first to third steps for each application target portion. The first and second steps may be performed again after the correction of the coating position.

Further, in the case of judging the suitability of application, a fourth step of imaging the paste application shape at the application target portion after applying the paste, the imaged application shape and a predetermined reference shape. And a fifth step of judging the paste application state at the application target portion based on the comparison result.

[0010]

In the present invention, the individual application target locations on the positioned substrate are imaged by, for example, a monitor camera, and the displacement amount between each individual application target location and a predetermined reference position is determined by, for example, image processing, and this determination is performed. The relative position is corrected so as to reduce the amount of displacement. As a result, unlike the prior art in which the coating positions corresponding to all the coating target positions are uniformly corrected, the coating positions are individually corrected, so that the specific coating positions are corrected correctly, but other It is possible to correct the coating position completely. Then, if the displacement amount is measured again after the correction, it becomes possible to confirm whether or not the coating position has been corrected to a predetermined position.

After the paste application, the same monitor camera captures an image of the paste application shape at the application target site and compares the captured application configuration with the reference profile to determine the paste application state at the application target site. The suitability of can be grasped.

[0012]

EXAMPLE An example of the present invention will be described in detail with reference to the drawings, taking as an example a case where a TFT array substrate is manufactured using a silver paste. FIG. 1 is an external perspective view of a paste applying apparatus according to an embodiment of the present invention. This paste application device includes a positioning unit 1, a conveyor 2, a discharge conveyor 3, a positioning mechanism 4, an orthogonal robot 5, an application mechanism 6, a monitor camera 7, a visual device 8, and the like.

The positioning unit 1 and the positioning mechanism 4 are for mechanically positioning and fixing the TFT array substrate transferred from the previous step for silver paste coating, and the transfer conveyor 2 is a TFT from the previous step. The array substrate is conveyed in the direction of the arrow. The discharge conveyor 3 discharges the TFT array substrate after the silver paste is applied to the next step.

Further, the orthogonal robot 5 controls the movement of the coating mechanism 6 and the monitor camera 7 in the horizontal direction (X and Y axis directions) and the vertical direction (Z axis direction) under the control of a control mechanism (not shown). For example, 3
A commercially available robot is used as the axis orthogonal coordinate type robot. The coating mechanism 6 will be described later in detail with reference to FIG.

As the monitor camera 7, for example, a CCD (solid-state image sensor) is used, and the T mounted on the positioning unit 1 is used.
The application target portion on the FT array substrate and the application shape after applying the silver paste are imaged to recognize the respective images, and the signal is transmitted to the visual device 8. Based on this transmitted signal, the visual device 8 calculates and obtains a predetermined point, for example, the center position of the application target location, and after applying the silver paste, the application shape recognized by the image and the predetermined reference shape. To compare. The shapes are compared by, for example, area comparison. When the area of the applied shape is smaller than the reference area, the applying mechanism 6 performs the applying process as described later.

As shown in FIG. 2, the coating mechanism 6 comprises a coating mechanism base 21 mounted on the orthogonal robot 5, a syringe base 13 mounted on the coating mechanism base 21 via a slide rail 12, and the like. . As a result, the syringe base 13 can move in the vertical direction with respect to the coating mechanism base 21. A syringe holder 14 holds a syringe 16 containing silver paste on the syringe base 13. A coating nozzle 17 is attached to the syringe 16. A tension spring 15 is attached between the application mechanism base 21 and the syringe base 13. A downward load is constantly applied to the syringe base 13 by the action of the tension spring 15. The contact detection sensor 19 is held by the sensor holder 20 on the application mechanism base 21. Contact sensor 1
The tip of 9 is in contact with the syringe base 13, and thus the displacement of the syringe base 13 can be detected. That is, the coating nozzle 17 is the TFT array substrate 11
When it comes into contact with, the syringe base 13 slides and the contact detection sensor 19 operates.

Next, the operation of this embodiment will be described with reference to FIGS. Note that FIG. 3 shows a state in which the TFT array substrate 11 is positioned at a predetermined position on the positioning portion 1 by the positioning mechanism 4. That is, from the pre-process (upstream) not shown, the TFT array substrate 1
1 is carried in (step (hereinafter abbreviated as S) 1), and this is guided to a predetermined portion of the positioning portion 1 to perform positioning of the outer die (S2). Next, the monitor camera 7 attached to the orthogonal robot 5 together with the coating mechanism 6 is moved to a coating position corresponding to one coating target location on the TFT array substrate 11 thus positioned, and the relevant location is imaged and positioned. Measurement is performed (S3). Then, based on this image pickup, the central position of the application target portion is calculated in the visual device 8.

In this case, it is determined whether the amount of displacement of the application target portion from the reference position is within a correctable range (S4),
If it is out of the range, the processes of S2 to S4 are repeated a predetermined number of times. If the measurement result after the repetition is insufficient, the operation is stopped due to an error (S6). On the other hand, when it is determined in S4 that it is within the correctable range, the position correction (coordinate correction) of the coating function by the control mechanism is performed based on the calculated displacement amount between the center position and the reference position (S7). . In order to confirm whether or not the correction has been made correctly, the processes of S3 and S4 may be executed.

Next, based on the above correction, the silver paste is applied from the application nozzle 17 to the corresponding portion (S).
8). After that, the quality of the coating result is determined (S9), and if it is defective, the processes of S8 to S9 are repeated a predetermined number of times. If the coating result is defective even after the predetermined number of repetitions, the error is stopped (S11). The determination of the coating failure will be described later.

Next, it is judged whether or not the coating has been completed for all the coating target portions (S12), and when it has been completed, the TFT array substrate 11 is carried out to the next step (position) (S14). If the application has not been completed, the application nozzle 17 is moved to the next application target site, and the application process for the site is performed in the same procedure (S13). FIG. 5 shows a procedure for judging whether the coating is good or bad. Referring to this figure, first, the monitor camera 7
An image of the coating state is recognized by the visual device 8 based on the coating shape imaged by (S15), the suitability of the silver paste coating is determined from the area of the coating shape, and it is determined whether the coating is normal. (S16). Then, when it is determined to be defective, the application mechanism 6 applies the silver paste to the relevant portion (S17). Then, the monitor camera 7 again takes an image (S18), and the visual device 8 determines whether the application has been normally performed (S19).

The above is an explanation of an example in which the present invention is applied to the application of silver paste on a TFT array substrate, but it goes without saying that the present invention can also be applied to the processing of other substrates on which similar paste application is performed. Is.

[0022]

As is apparent from the above description, according to the present invention, since the coating positions corresponding to the coating target positions are individually corrected, there are a plurality of coating target positions on the substrate. However, there is an effect that the paste can be accurately applied to each place. Moreover, since the determination of the coating result is also performed, there is an effect that the yield rate of the substrate after the paste coating is significantly improved.

[Brief description of drawings]

FIG. 1 is an external perspective view showing the configuration of a paste coating apparatus according to an embodiment of the present invention.

2A is a front view of a coating mechanism that constitutes the paste coating apparatus of FIG. 1, and FIG. 2B is a side view of the same.

FIG. 3 is an explanatory diagram showing an example of a TFT array substrate on which paste is applied by the paste applying apparatus of this embodiment.

FIG. 4 is a flowchart showing an overall processing procedure in this embodiment.

FIG. 5 is a flow chart showing a processing procedure of quality of coating in the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positioning part 4 Positioning mechanism 5 Cartesian robot 6 Coating mechanism 7 Monitor camera 8 Visual device

Claims (3)

[Claims] 1. A positioning means for positioning a substrate to be processed at a predetermined portion, a coating mechanism for coating paste on each of a plurality of coating target portions on the positioned substrate, and the coating mechanism and individual coating mechanisms. A first step of capturing an image of one application target location on the substrate in a paste application apparatus having a control mechanism that controls the relative position to the application position corresponding to the application target location, and the imaged application target A second step of detecting an amount of displacement between the location and a predetermined reference position; and a third step of correcting the relative position so as to reduce the detected amount of displacement, the first step To the third step are executed for each application target portion, a method for correcting the application position in the paste application device. 2. The correction method according to claim 1, wherein the first and second steps are performed again after the correction of the coating position. 3. A fourth step of imaging a paste application shape at the application target portion after applying the paste, and the imaged application shape and a predetermined reference shape are compared, and based on a result of the comparison. 5. The correction method according to claim 1, further comprising: a fifth step of determining a paste application state at the application target portion.