KR100535563B1 - Line-scan Inspection process with tilted moving TFT-LCD glass substrate - Google Patents

Abstract

According to the tilting feed line scan method of the present invention, the tilted feed glass substrate is line-scanned by a line scan camera to detect the gray value of the scanned pixel, and the difference value between the detected gray value and the intermediate gray value is determined. Comparing the gray value of each pixel in the peripheral region of the found defective pixel to a difference value of the average gray value of the test glass substrate when the difference value is greater than the hardware sensitivity threshold value. Comparing the detected detection threshold to a preset test sensitivity threshold, and if the difference is greater than the test sensitivity threshold, classifying the found defects into a specific class, sorting them by a size table of contents, and setting a specific size category. Compare the number of defects with a set number of limits, or compare the defect size of each category with the defect size set for each category. Since it includes the step of determining whether the large glass substrate is tilted at a constant angle, while tilting at a constant speed, the line scan inspection in-line, the process can be simple and stable operation, clean room space utilization and simplifying equipment It has the effect of reducing the cost and the inspection load due to particle contamination and the productivity improvement due to the improvement of the hourly processing capacity of the inspection process, and the inspection process capability by securing the stability to the vibration of the inspection area.

Description

Line-scan Inspection process with tilted moving TFT-LCD glass substrate}

The present invention relates to a tilting transfer line scan inspection method, and more particularly, to inspect defects of the glass substrate while minimizing vibration to the extent that the large glass substrate is inclined at a predetermined angle at high speed while not exceeding the depth of focus of the camera. To a tilting transfer line scan inspection method.

As is well known, glass substrates used in the manufacture of flat panel displays such as thin film transistor-liquid crystal displays (TFT-LCDs), plasma display panels (PDPs), and electro luminescent (EL) are glass melting furnaces. After melting the molten glass melted in a melting furnace) into a flat plate and a cutting process of cutting to meet the primary standards, it is selected as good or defective through cleaning and inspection process.

For example, Korean Patent Application No. 2002-30386 (filed date: Feb. 30, 2000) (Korean Patent Publication No. 2003-92653 (published date: 2003.12.6)) of the present applicant discloses a cleaning station for a glass substrate. The glass substrate that has undergone the cleaning process is stored in a container, also called a cassette, and transported to an inspection station, and the glass substrate stored in the container is unloaded by a handler. Loading on the test station. Inspection station contains inclusions, stains, scratches, bevel chips, cutting chips, and cracks in glass substrates such as blisters and stones. (Crack) is checking for defects.

However, in the past, an area scan method was used to shoot multiple cameras while moving, but this is complicated and inaccurate, and has a disadvantage in terms of speed. It is in the spotlight recently. Moreover, it is important to support the glass substrate without inspecting the glass substrate without physically contacting the surface, to damp the vibration of the glass surface, and to enable the high speed movement of the glass substrate. In this case, particle contamination occurs due to the flow of the clean room from the top to the bottom, and it is difficult to focus the camera due to the surface sagging due to the weight of the large glass substrate. There is a problem that is difficult to handle the main maintenance targets, such as lighting and camera.

Accordingly, the present applicant in the Korean Patent Application No. 2002-67197 (Application Date: October 31, 2002) (Korean Patent Publication No. 2004-38301 (Publishing Date: 2004.5.8)), unloading the glass substrate loaded horizontally inclined Provided is a glass substrate transfer system. The conveying system includes a system main body, horizontal conveying means installed on the system main body so as to support both edges of the glass substrate and transport them horizontally, and an air-floating which floats the glass substrate on the horizontal conveying means by blowing of air. And tilting means for tilting the horizontal conveying means and the air floating means so that the glass substrate on the horizontal conveying means is inclined, and inclined conveying means installed to support and transport the lower end of the glass substrate which is inclined to the tilting means. Consists of.

However, this also makes it difficult to set the air volume of the air-floating means according to the thickness, size and composition of the large glass substrate, and is particularly sensitive to vibration in the case of a thin, large and lightweight glass substrate, which is tilted from the cleaning station to the inspection station. Although there is an urgent need for the development of a line-scanning technology for thin and lightweight glass substrates, there has been no development as a technology to meet the requirements.

Accordingly, the present invention has been devised accordingly, and an object thereof is to provide a tilting transfer line scan inspection method which can reduce particle load by minimizing particle contamination.

Another object of the present invention is to provide a tilting transfer line scan inspection method capable of stably maintaining the inspection area within the depth of focus area of the camera.

Still another object of the present invention is to provide a tilting transfer line scan inspection method capable of minimizing the deviation of the inspection process according to the thickness, size and composition of the glass substrate.

Still another object of the present invention is to provide a tilting transfer line scan inspection method capable of ensuring rapid and easy maintenance.

In the tilting feed line scan inspection method of the present invention, the tilting feed line scan inspection method includes: scanning the tilted conveyed glass substrate by a line scan camera to detect gray values of the scanned pixels, and detecting the detected gray values. Comparing the difference value between the gray value and the intermediate gray value with a preset hardware sensitivity threshold value; and if the difference value is greater than the hardware sensitivity threshold value, the gray value of each pixel in the peripheral region of the found defective pixel is measured. Comparing the difference from the average gray value of the substrate to a preset inspection sensitivity threshold; if the difference is greater than the inspection sensitivity threshold, classify the found defects into a particular class and sort by size table of contents to find a specific size category. And compare the number of defects in a given size category with the set number of limits, or compare the defect size in each category Judging good or bad by comparing the defect size set according to the note.

According to the present invention, since the large glass substrate is tilted at a constant angle and is tilted at constant velocity, the line scan is inspected inline, so that the process can be operated simply and stably, and thus, the cost of the clean room space and the simplification of the equipment can be reduced. It has the effect of improving the productivity of the inspection process by reducing the inspection load due to the reduction and contamination of particles and improving the processing capacity per hour of the inspection process, and ensuring the stability of the vibration of the inspection area.

Hereinafter, a line scan inspection system for executing a tilting transfer line scan inspection method according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a front view showing a schematic configuration of a system for executing a tilting feed line scan inspection method of the present invention, and FIG. 2 is a front view showing a tilting feed. As shown, the tilting transfer line scan inspection system according to a preferred embodiment of the present invention is a conveyor body 10 for conveying the glass substrate (1), and both ends of the glass substrate (1) on the conveyor body (10) Air-floating device (40) for supporting the edge of the horizontal conveying apparatus 20 is installed to be transported horizontally and the glass substrate 1 placed on the horizontal conveying apparatus 20 by the blowing of air (Fig. 3). ), A tilting device 50 for tilting the horizontal feeder 20 and the air-floating device 40 so that the glass substrate 1 placed on the horizontal feeder 20 can be inclined, and the tilting device 50. It is composed of the inclined transfer device 60 is installed to be transported while supporting the lower end of the glass substrate (1) which is inclined to the).

In the horizontal conveying apparatus 20, the conveyor frames 21a and 22a are installed in parallel on the conveyor body 10 along the conveying direction 2 of the glass substrate 1, and the conveyor frames 21a and 22a are glass. When erecting both ends of the substrate 1, that is, the glass substrate 10, a plurality of rollers 21b and 22b for supporting the edges of the lower end 1a and the upper end 1b have a constant distance around the shafts 21c and 22c. It is mounted to rotate freely. The rollers 21b and 22b rotate by the operation of the servomotor 24.

As shown in FIGS. 1 to 3, the air floating apparatus 40 includes a glass substrate in which the horizontal transfer apparatus 20 is supported by the lower end 1a and the upper end 1b by rollers 21b and 22b. It is provided along the conveying direction of the glass substrate 1 so that 1 may be lifted from the rollers 21b and 22b, and a number of nozzle holes 41a for ejecting air to the glass substrate 1 are long. A plurality of air blowing pipes 41 are formed along the direction. The pipe 41 has an air blower 44 for generating air, and an air filter 45 for filtering the air from the blower 44 and supplying it to the pipe 41, preferably 0.3. It is composed of a HEPA (High efficiency particlulate air filter) for filtering the fine particles of about μm. The air blower 44 may be replaced by a known air compressor and an air control unit that controls the flow rate and pressure of the air.

1 and 2, the tilting device 50 has a tilting frame 51 on which the horizontal feeder 20 and the air-floating device 40 are mounted, and the rotational movement of the tilting frame 951. It consists of a shaft 53 supported by the bearing 52 so as to be supportable, and a servomotor 55 for rotating the shaft 53 so that the glass substrate 1 is 5 to 20 with respect to the vertical axis 58. Tilt at a tilt angle θ of about degrees, preferably tilt at a tilt angle of about 10 degrees.

In addition, the inclined feeder 60 is inclined conveying conveyor 61 is installed on the tilting frame 51 of the tilting device 50 to be parallel to the conveyor frame (21a, 22a) of the horizontal feeder 20, at regular intervals It consists of a plurality of rollers 64 mounted on the conveyor 61 so as to be rotatable about the shaft 62, and a servo motor 63 for driving the rollers 64 to rotate. Support 1a) and incline transfer.

As shown in FIGS. 4 and 5, when the glass substrate 1 inclinedly fed by the inclined feeder 60 passes through the center of the line scan inspector 70, the line scan inspector 70 is formed of glass. The surface defects inside and outside the board | substrate 1 are examined. The line scan inspector 70 is installed on one side of the upright rectangular frame 72 and the passage of the glass substrate 1 so that the inclined glass substrate 1 passes through the center of the glass substrate 1. A transmission illumination system 74 for irradiating light and a reflection illumination system 76 installed on the other side of the passage of the glass substrate 1 to reflect the light irradiated onto the glass substrate 1 by the transmission illumination system 74; Of the glass substrate 1 and the glass substrate 1 reflected by the transmissive illumination system 74 and reflected by the transmissive illumination system 74 on the opposite side to the transmissive illumination system 74 in the vertical direction of the frame 72. A plurality of, preferably 16, line scan cameras 80 for generating digital image information by capturing images in units of lines inside and outside, and a plurality of line scan cameras 80 by sensing the transfer of the glass substrate 1. Sensing means 78 which transmit a signal to start the inspection, and the outside of the frame 72 It is provided each including a transmission illumination system 74 and the reflection illumination system 76, a lamp light source (82) provided respectively on the outside of the frame 72 as the illumination source.

The inspection method of the tilting feed line scan inspection system configured as described above is as follows.

The large glass substrate 1 having been cleaned is horizontally transported by the air-floating device 40 in the horizontal conveying device 20, and is then inclined by the tilting device 50. Subsequently, the inclined glass substrate 1 is transferred by the inclined transfer device 60 to pass through the center of the line scan inspector 70. The detection means 78 detects this and operates the line scan camera 80, thereby processing the image information obtained by line scanning the defects inside and outside the glass substrate 1 in real time and providing defect information to the inspector.

In detail, first, the line scan camera 80, when the glass substrate 1 passes, to obtain the gray value of the glass image as a digital image, as shown in Figure 6, the line with respect to the glass substrate 1 The scan is executed and the gray value of the scanned pixel is detected (S1). A pixel is a unit element of a digital image, and the gray value GV corresponds to a brightness value. The gray value of the scanned pixel is between 0 and 255, where 0 is black and 255 is white, so that a bright image without combining has a gray value of 244, and a dark image with defects has a gray value of 148. Have

Subsequently, the difference between the detected gray value and the intermediate gray value is compared with a preset hardware sensitivity threshold value (S2). Even if there is at least one pixel above this hardware sensitivity threshold, it is considered a defect. This threshold is set by changing HWPP_SENSITIVITY_BRIGHT and HWPP_SENSITIVITY-DARK in the SENSIC parameter setting manager.

Thereafter, if the difference is greater than the hardware sensitivity threshold value, the gray value of each pixel in the peripheral region of the found defective pixel is compared with the preset inspection sensitivity threshold value with the average gray value of the test glass substrate (S3). ). Again, only areas that exceed the test sensitivity threshold are considered defects. These thresholds are set in INSPECTION_SENSITIVITY_BRIGHT and INSPECTION_SENSITIVITY_DARK in the SENSIC parameter setting manager.

Next, if the difference is greater than the test sensitivity threshold, the found defects are classified into a specific class, sorted by size table of contents, and defined as a specific size category (S4). Each category has different size limits, and of course, the number of categories and the size limit of each category can be adjusted.

Subsequently, the number of defects of the predetermined size category is compared with the set limit number, or the defect size of each category is compared with the defect size set according to each category to determine whether the test glass substrate is good or not (S5). As a result of the determination, for example, the color of the glass on the screen may be changed to red, and the corresponding input / output signal may be output. When evaluating defects, it is of course possible to display the size in the x and y directions or the geometric size on the screen.

As described above, the tilting transfer line scan inspection method of the present invention is a line scan inspection inline while tilting the large glass substrate at a constant angle while tilting at a constant speed, so that the process can be operated in a simple and stable manner, thus providing a clean room space. Productivity improvement due to reduction of cost due to utilization and simplification of equipment, reduction of inspection load due to particle contamination and improvement of hourly processing capacity of inspection process, and improvement of inspection process capability through securing stability against vibration of inspection area Has the effect of

Tilting feed line scan method of the present invention as described above is only one embodiment, the present invention is not limited to the above embodiment, as claimed in the following claims, the gist of the present invention Without departing from the scope of the present invention to those skilled in the art should be considered to be included in the technical spirit of the present invention to the extent that changes or modifications can be made.

1 is a schematic diagram showing a system for executing a tilting transfer line scan inspection method according to an embodiment of the present invention,

2 is a front view showing the tilting feed of FIG.

3 is a cross-sectional view showing an air blowing pipe of the air floating device,

4 is a plan view of the line scan inspector of FIG.

5 is a perspective view of the line scan inspector of FIG.

Figure 6 is a flow chart for executing the tilting feed line scan method of the present invention.

<Description of the symbols for the main parts of the drawings>

1: glass substrate 2: conveying direction

10: conveyor body 20: horizontal feed device

21a, 22a: conveyor frame 21b, 22b: roller

21c, 22c: shaft 24: servo motor

40: air floating device 41: blowing pipe

41a: nozzle hole 44: air blower

45: air filter 50: tilting device

51: tilting frame 52: bearing

53: shaft 55: servo motor

58: vertical axis 60: inclined feeder

61: inclined transfer conveyor 62: shaft

63: servo motor 64: roller

70: line scan checker 72: rectangular frame

74: transmission lighting system 76: reflection lighting system

78: detection means 80: line scan camera

82: lamp lighting source

Claims (2)

In the tilting feed line scan inspection method, Detecting the gray value of the scanned pixel by line scanning the tilted conveyed glass substrate by a line scan camera; Comparing the difference between the detected gray value and the intermediate gray value with a preset hardware sensitivity threshold value; If the difference is greater than the hardware sensitivity threshold, comparing the gray value of each pixel in the peripheral region of the found defective pixel with a difference between the average gray value of the test glass substrate and a preset inspection sensitivity threshold; , If the difference is greater than the test sensitivity threshold, classifying the found defects into a particular class, sorting them by size table of contents, and setting them into a particular size category; And comparing the number of defects of a predetermined size category with a set limit number, or comparing the defect size of each category with a defect size set according to each category, to determine whether the tilted feed line scan is successful. The method of claim 1, The gray value of the scanned pixel is a value between 0 and 255, where 0 is black, 255 is white, and a bright image without combining has a gray value of 244, and a defective dark image has a gray value of 148. Tilting feed line scan inspection method characterized in that it has a.