KR20100023124A - Inspection apparatus and method for ink-jet printing state of color filter process - Google Patents

Abstract

PURPOSE: A print state inspecting equipment of a color filter substrate and an inspecting method thereof are provided to improve manufacturing efficiency by easily measuring the fault of a color filter substrate. CONSTITUTION: A light source(20) radiates light from the lower part of a color filter substrate(10) to the color filter substrate. A 2D image detector(30) detects the intensity of a transmitted light transmitting the color filter substrate. An image processing calculator(40) executes an image processing based on a pixel of the 2D image detector. A fault of the color filter substrate is determined according to rate between a red, a green, and a blue according to the intensity of the transmitted light.

Description

Inspection apparatus and method for printing state of color filter substrate {Inspection apparatus and method for Ink-Jet printing state of color filter Process}

According to the present invention, red and green colors are produced due to process defects such as ink coating amount unevenness and application position inaccuracy when the color filter is produced by using an inkjet printing method, which is one of methods for manufacturing color filters in a liquid crystal display device manufacturing process. Green, Blue The color uniformity of each color pattern may be degraded. The present invention relates to a printing state inspection device and an inspection method of a color filter substrate capable of detecting such defects.

As a method of manufacturing the color filter, a photoresist process and an inkjet printing method may be used.

1 is a cross-sectional structure of a color filter substrate fabricated by a general photo resist process.

The color filter manufacturing method of the photoresist process is a process in which a predetermined color pigment is printed on the original glass substrate in order to form a predetermined color filter, and then the exposure, development, and etching processes are repeatedly formed for each color printing step sequence. to be. As described above, the color filter produced by the photoresist process has an advantage that the printing state of the film in the local area is superior to the product produced by the inkjet printing process. Such a photoresist process requires a large amount of color pigments to print the entire original glass and remove unnecessary portions, and requires a cost and space for exposure, development, and etching process facilities.

On the other hand, the inkjet printing method does not require the above process steps, it can significantly reduce the pigment cost and space can have a number of advantages. Despite many of the above advantages, the inkjet printing method has problems to be solved.

FIG. 2 is a cross-sectional view of a color filter substrate produced by a normal inkjet printing method, and shows a state in which the amount of ink ejected by using a black matrix BM as a partition is printed uniformly and uniformly.

If the amount of ink (Drop or Dispensing) is not constant, the manufactured color filter substrate is defective.

3 is a cross-sectional structure showing the kind of the predictable defect of the color filter produced by the inkjet printing method.

In inkjet printing method, each nozzle should be ejected (Drop or Dispensing) at the correct position using piezoelectric to nozzles corresponding to each color. Color difference may occur for each pattern, and in severe cases, light leakage may occur because the color pattern cannot be filled with a predetermined pigment. In addition, even in the color pattern, the distribution of pigments is not constant, so that a difference in color may occur.

The conventional measuring method used to inspect the defects as shown in Fig. 3 in the product produced by such an inkjet printing method is the inspection of a local region of several tens of microns size using an optical system at the center or a specific position inside the color pattern. The printing state was inspected through. However, even if the product printed by the inkjet printing method does not have uniformity in the discharge volume even within the color pattern, it may be out of process control standard depending on the measuring method, so whether the product produced by the inkjet printing method is defective or the measurement performance of the equipment is a problem. There is a problem that it is difficult to accurately identify.

An object of the present invention for solving the above problems is to transmit the transmitted light transmitted through the color filter substrate by using the focusing optical system without measuring the local area of the spot size of several tens of microns, each red ( The printing status inspection equipment and inspection method of the color filter substrate that can monitor the product printed by the inkjet printing method by calculating the intensity and color ratio of the transmitted light transmitted through the red, green, and blue color patterns. To provide.

In addition, another object of the present invention is to provide a printing state inspection equipment and inspection method of the color filter substrate to improve the productivity by measuring the average color change inside the color pattern to improve the monitoring accuracy and efficiency of the process.

The printing state inspection equipment of the color filter substrate of the present invention is manufactured by an inkjet printing method, the printing state of the liquid crystal display device color filter substrate, which is printed in red, green, and blue colors, respectively, with a color pattern 11 having a predetermined size and shape. In the printing state inspection equipment of the color filter substrate for inspecting the light filter 20, which is provided on the lower portion of the color filter substrate (10) for irradiating light to the color filter substrate (10); A two-dimensional image detector (30) provided on the color filter substrate (10) for detecting the intensity of transmitted light transmitted from the light source (20) to the color filter substrate (10); Each color pattern 11 is image-processed for each pixel 31 of the 2D image detector 30 based on the intensity of transmitted light detected by the 2D image detector 30, and the inside of the color pattern 11 is An area corresponding to the color pattern 11 having the same shape as that of the color pattern 11 and having a smaller size than the color pattern 11 is adopted as the pixel 31 of the two-dimensional image detector 30 so that each pixel ( An image processing operation unit 40 for determining a defective color filter substrate by calculating ratios of red, green, and blue according to the intensity of transmitted light corresponding to 31); Characterized in that comprises a.

In addition, the pixel 31 of the two-dimensional image detector 30 is characterized in that the area corresponding to 60 to 95% of the size of the color pattern 11 is adopted.

In addition, the defect is a poor color purity, poor color uniformity, the ink is filled with the color pattern 11 overflows to cover the adjacent color filter (over filling) and less ink in the color pattern 11 It is characterized in that the under filling (under filling) to be filled.

In addition, a light splitter positioned between the light source 20 and the color filter substrate 10 to separate a part of light irradiated from the light source 20 and to radiate the remaining light to the color filter substrate 10 ( A beam splitter 50 and a photodetector 60 for detecting the intensity of a part of the light separated by the beam splitter 50 are further provided, and detected by the two-dimensional image detector 30. When the intensity of the transmitted light is less than or greater than the reference value, it is characterized by adjusting the intensity of the light irradiated by the light source 20 by feeding back.

The printing state inspection method of the color filter substrate of the present invention is manufactured by the inkjet printing method, the printing state of the liquid crystal display device color filter substrate, which is printed in red, green, and blue colors with a color pattern 11 having a predetermined size and shape, respectively. A method of inspecting a printing state of a color filter substrate, the method comprising: a) irradiating light onto the color filter substrate 10 by means of a light source 20 provided below the color filter substrate 10 to project the light; b) detecting the intensity of transmitted light transmitted from the light source 20 through the color filter substrate 10 by a two-dimensional image detector 30 provided on the color filter substrate 10; c) image the intensity of the transmitted light detected by the 2D image detector 30 for each pixel 31 of the 2D image detector 30, wherein the color pattern 11 is formed inside the color pattern 11. An area corresponding to the color pattern 11 having the same shape as that of the color pattern 11 and smaller than the color pattern 11 is adopted as the pixel 31 of the 2D image detector 30 to correspond to each pixel 31. Calculating ratios of red, green, and blue according to the intensity of transmitted light, respectively; d) determining the failure of the color filter substrate using the calculated ratio; Characterized in that comprises a.

In addition, a light splitter positioned between the light source 20 and the color filter substrate 10 to separate a part of light irradiated from the light source 20 and to radiate the remaining light to the color filter substrate 10 ( A beam splitter 50 and a photodetector 60 for detecting the intensity of a part of the light separated by the beam splitter 50 are further provided, and detected by the two-dimensional image detector 30. Adjusting and feeding back the intensity of the light irradiated by the light source 20 when the intensity of the transmitted light is less than or greater than a reference value; Characterized in that further comprises.

In addition, measuring the chromaticity of each color pattern 11 of the color filter substrate; and using the measured chromaticity value, intensity data of the transmitted light detected in step b) and the color ratio value calculated in step c) Obtaining a color ratio coordinate value of each color pattern 11 of the filter substrate; Characterized in that further comprises.

The method may further include creating a comparison correction table by comparing the obtained color ratio coordinate values with actual color coordinate values; Characterized in that further comprises.

In addition, before the step a) measuring the reference to determine the amount of transmitted light; Characterized in that further comprises.

In the inspection of the printing state of the color filter substrate manufactured by the inkjet printing method, the average of the inside of the color pattern 11 is not measured by measuring the defect of the product due to the ink printing heterogeneity in the color pattern 11 in the local area of several tens of micrometers. By measuring the change of color, the defect of the color filter substrate can be measured quickly, accurately and easily, thereby increasing the manufacturing efficiency.

Hereinafter, the printing state inspection equipment and inspection method of the color filter substrate of the present invention with reference to the accompanying drawings.

The printing state inspection equipment of the color filter substrate is manufactured by the inkjet printing method to inspect the print state defect of the color filter substrate of the liquid crystal display device in which the red, green, and blue colors are printed with the color patterns 11 having a certain size and shape. However, the present invention adopts a smaller area than the inside of the color pattern 11 rather than measuring a product defect due to ink printing inhomogeneity in the color pattern 11 in a local area of several tens of micrometers. It is characterized in that to measure the defect inspection faster, more accurate and easier.

4 is a view showing a schematic structure of a printing state inspection equipment of a color filter substrate according to the present invention.

As shown, the printing state inspection equipment of the color filter substrate of the present invention is provided on the lower portion of the color filter substrate (10) a light source 20 for irradiating light; A two-dimensional image detector (30) provided on the color filter substrate (10) for detecting the intensity of transmitted light; An image processing operation unit 40 for processing the detected intensity of the transmitted light for each pixel 31 to calculate a ratio of red, green, and blue according to the intensity of the transmitted light to determine a defect of the color filter substrate; It is made, including.

The light source 20 is provided below the color filter substrate 10 and serves to irradiate light to the color filter substrate 10. The irradiated light is projected onto the color filter substrate 10 to be transmitted.

The two-dimensional image detector 30 is provided on the color filter substrate 10 to detect the intensity of transmitted light transmitted from the light source 20 to the color filter substrate 10. In this case, the 2D image detector 30 preferably uses a color 2D CCD (Charged-Coupled Device) camera.

The two-dimensional image detector 30 may be provided with an optical system (not shown), and may acquire an enlarged image by a magnification lens and a magnification lens capable of enlarging an image to be measured of a color filter substrate projected by a light source. . In this case, since the two-dimensional image detector 30 uses a magnification lens, a device that can be adjusted up and down to focus and a stage (not shown) on which the color filter substrate 10 is mounted are mounted. The light source is designed to project light onto the color filter substrate. The stage may also be moved by drive means (not shown) to move the measurement to a desired position.

The image processing operator 40 performs an image processing on each pixel 31 of the intensity of transmitted light detected by the 2D image detector 30. In the image processing, the two-dimensional image detector 30 of the color pattern 11 corresponding to the area having the same shape as the color pattern 11 and having a smaller size than the color pattern 11 is formed inside the color pattern 11. In this method, the ratio of red, green, and blue according to the intensity of the transmitted light corresponding to each pixel 31 is calculated. The defective color filter substrate is determined using the calculated color ratio.

The image processing operation unit 40 is programmed to select the color filter image projected by the light source 20 for each pixel 31 of the 2D image detector 30, and for each pixel 31. Separate the ratios so that you can calculate the ratio (color purity) of the color. The image acquired by the 2D image detector 30 and the result calculated by the image processing unit 40 are expressed through a display unit (not shown).

When the printing state of the color filter substrate is overfilled as shown in FIG. 3, the adjacent color filters are covered and color ratios are mixed and detected to determine a defect, and when underfilling is performed. Since light leakage occurs and the intensity of transmitted light increases, it is determined that the defect is caused. In addition, poor color purity and poor color uniformity can be detected using the intensity of transmitted light and the detected chromaticity.

In this case, the pixel 31 of the two-dimensional image detector 30 is preferably adopted to the area corresponding to 60 to 95% of the size of the color pattern (11). If the adopted area is too small for the size of the color pattern 11, it is difficult to detect defects of the ink filled in the color pattern 11 as a whole, and if the adopted area is equal to the size of the color pattern 11, The area and the color pattern 11 should be matched, but it may be changed by micro vibration, which makes it difficult to measure and the contrast is generated at the boundary between the color pattern 11 and the black matrix (BM). If the adopted area is too large to be larger than the size of the color pattern 11, the portion of the black matrix BM must be removed and the measurement accuracy is degraded so that the adopted area has an appropriate size.

As described above, the present invention can evaluate the uniformity of the color inside the color pattern 11 produced by the inkjet printing method by measuring the average color change using the printing state inspection equipment of the inkjet liquid crystal display device color filter. The method of measuring localized areas of tens of micrometers can be improved, increasing the reliability of the measured values as measuring equipment for inkjet printing processes. In addition, it is possible to quickly and easily measure the phenomenon caused by poor local homogeneity in the color pattern 11 of the color filter substrate produced by the inkjet printing method.

In addition, in order to compensate for the change in intensity of the transmitted light that can be changed during the measurement, a device for detecting the light intensity irradiated by the light source 20 is required to monitor the transmitted light in the middle of the transmitted light path, and the device is the light source. It serves to feed back so that 20 transmits the transmitted light of a constant intensity.

For this configuration, the light is positioned between the light source 20 and the color filter substrate 10 to separate some of the light irradiated from the light source 20 and to radiate the remaining light to the color filter substrate 10. A splitter 50 and a photodetector 60 for detecting the intensity of a portion of the light separated by the splitter 50 are further provided.

Accordingly, when the intensity of the transmitted light detected by the two-dimensional image detector 30 is less than or greater than the reference value, the feedback may be irradiated with a constant intensity of the light intensity of the light source 20 detected by the photodetector 60. Done.

The printing state inspection method of the color filter substrate of the present invention comprises the steps of: a) irradiating light onto the color filter substrate 10 by means of a light source 20 to project it; b) detecting the intensity of transmitted light transmitted through the color filter substrate 10 by a two-dimensional image detector 30; c) image processing the intensity of the transmitted light detected by the 2D image detector 30 for each pixel 31 by the image processing operation 40; It is made, including.

5 is a flowchart illustrating a method of measuring a color printing state and color uniformity according to the present invention, and FIG. 6 is a flowchart illustrating a step of calculating a color ratio from the measurement result obtained in FIG. 5.

First, the color filter substrate is positioned between the light source 20 and the two-dimensional image detector 30, and then the light irradiated from the light source 20 is projected onto the color filter substrate 10. The projected transmitted light acquires an image of red, green and blue color filters transmitted by the light source in the two-dimensional image detector 30. Subsequently, the image data acquired by the color two-dimensional image detector 30 is sent to the image processing operation unit 40 to extract the intensities of the red, green, and blue components for each color pattern 11 of the color filter of the liquid crystal display device. The ratio is calculated.

In this case, it is preferable to measure a reference in order to determine a reference of the amount of transmitted light through which the light emitted by the light source passes through the color filter substrate 10, and the light on the color filter substrate 10 formed by an inkjet printing method. Before irradiation, the intensity of the light source is measured to determine whether the intensity of the incident light is appropriate or constant. At this time, after measuring the intensity of a suitable light source using a photodetector installed to monitor the intensity of light, if the reference value does not reach or exceeds a predetermined reference value, it is fed back to adjust the intensity of light.

After measuring the intensity of the light source 20, the light irradiated by the light source 20 is projected onto the color filter substrate.

The two-dimensional image detector 30 obtains an image of the color filter of the liquid crystal display device having passed through the color filter substrate 10 from the light source 20.

The intensity of the transmitted light is calculated by classifying the color patterns 11 (red, green, blue) of the color filter substrate from the obtained image.

FIG. 7 is an exemplary diagram illustrating a color distribution of transmitted light transmitted for each color pattern 11 of the color filter substrate.

Although the transmitted light transmitted through each color pattern 11 of the color filter substrate is different in the ratio of red, green, and blue, colors are represented by the ratio of three primary colors, and thus can be separated for each component of each color. The light transmitted through each color pattern 11 of the color filter substrate is measured by the intensity of red, green, and blue components in the same manner as the tristimulus calculation method. X (red stimulus value), Y (green stimulus value), Z (blue) Values for the three stimulus values of

The purity of the color is calculated using the three magnetic pole values obtained from each color pattern 11 of the color filter substrate. This can be calculated using a commercially available image processing algorithm. For example, the purity of color for red is the sum of the stimulus values of red (X), red (X), green (Y), and blue (Z). Defined by dividing by. Let this value be defined as the purity (color ratio) of the color of each color pattern 11.

At this time, when the intensity of the light source is changed, the intensity of light transmitted through each color pattern 11 of the color filter substrate is changed, so that a constant value cannot be obtained. Therefore, a photodetector installed to monitor the intensity of the light source is measured before measurement. You should always set a reference value for a certain intensity.

In this way, the printing state of the color filter substrate manufactured by the inkjet printing method can be easily and quickly measured.

Furthermore, the color coordinate values can be inferred from the purity values of the colors of each color pattern 11 of the color filter substrate calculated by the above method using a comparison table of the reference values managed by the conventional methods (color coordinates). .

As described above, the present invention performs a defect inspection by measuring the change of the average color. Thus, the method used to measure the printing state of each color pattern 11 of the conventional color filter substrate is a color filter substrate by measuring a local area. Compared to the method of measuring the entire area of the long measurement time can be significantly improved.

In the conventional inspection method, when the color filter substrate manufactured by the inkjet printing method is measured, the printing thickness in each color pattern 11 is not uniform due to the characteristics of the process. There is a disadvantage in that the change width of the color coordinate value is largely measured for each position in the entire area.

By measuring the printing state of each color pattern 11 of the color filter substrate manufactured by the inkjet printing method by the method of the present invention, the homogeneity of colors in the entire surface or region of interest (ROI) of each color pattern 11 is measured. The degree can be calculated to compensate for the disadvantages of existing measurement methods.

In addition, measuring the chromaticity of each color pattern 11 of the color filter substrate; and using the measured chromaticity value, the intensity data of the transmitted light detected by the two-dimensional image detector 30 and the calculated color ratio value Obtaining a color ratio coordinate value of each color pattern 11 of the filter substrate; It is preferable to further include.

In addition, it is preferable to make a comparison correction table by comparing the obtained color ratio coordinate values with actual color coordinate values.

Although the preferred embodiments of the present invention have been described above, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. have.

1 is a cross-sectional structure of a color filter substrate produced by a general photo process.

2 is a cross-sectional view of a color filter substrate produced by a normal inkjet printing method.

Figure 3 is a cross-sectional structure showing the kind of foreseeable defects of the color filter produced by the inkjet printing method.

Figure 4 is a view showing a schematic structure of the printing state inspection equipment of the color filter substrate according to the present invention.

5 is a flowchart illustrating a method of measuring a color printing state and color uniformity according to the present invention;

6 is a flowchart for explaining a step of calculating a color ratio from the measurement result obtained in FIG.

7 is an exemplary diagram showing a color distribution of transmitted light transmitted for each color pattern 11 of a color filter substrate.

* Description of the symbols for the main parts of the drawings *

10: color filter substrate 11: color pattern

20: light source 30: two-dimensional image detector

31: pixel 40: image processing calculator

50: beam splitter 60: photodetector

Claims (11)

It is manufactured by the inkjet printing method, and the color pattern 11 having a certain size and shape is printed on the printing state inspection equipment of the color filter substrate which inspects the poor printing state of the color filter substrate of the liquid crystal display device in which the red, green, and blue colors are respectively printed. In A light source 20 provided below the color filter substrate 10 to irradiate light to the color filter substrate 10; A two-dimensional image detector (30) provided on the color filter substrate (10) for detecting the intensity of transmitted light transmitted from the light source (20) to the color filter substrate (10); Image intensity of the transmitted light detected by the 2D image detector 30 for each pixel 31 of the 2D image detector 30 is the same as the color pattern 11 inside the color pattern 11. The area corresponding to the color pattern 11 having a shape and smaller than the color pattern 11 is adopted as the pixel 31 of the two-dimensional image detector 30, so that the transmitted light corresponding to each pixel 31 is formed. An image processing operation unit 40 for determining a defective color filter substrate by calculating ratios of red, green, and blue according to intensity; Printing state inspection equipment of the color filter substrate, characterized in that comprises a. The method of claim 1, And the pixel 31 of the two-dimensional image detector 30 is adopted with an area corresponding to 60 to 95% of the size of the color pattern 11. The method of claim 1, The defects include color purity defects, color uniformity defects, overfilling of the color pattern 11 with an excessive amount of ink to cover adjacent color filters, and less ink filling the color pattern 11. The printing state inspection equipment of the color filter substrate, characterized in that the under filling (under filling). The method of claim 1, A beam splitter positioned between the light source 20 and the color filter substrate 10 to separate some of the light emitted from the light source 20 and to radiate the remaining light to the color filter substrate 10. 50 and a light detector 60 for detecting the intensity of a portion of the light separated by the beam splitter 50, the transmitted light detected by the two-dimensional image detector 30 If the intensity is less than or greater than the reference value of the printing state inspection equipment of the color filter substrate, characterized in that for controlling the intensity of the light irradiated by the light source (20). Inspection method of printing state of color filter substrate which inspects the printing state defect of color filter substrate of liquid crystal display device which is manufactured by inkjet printing method and has red, green and blue colors printed with color pattern 11 having a certain size and shape. To a) irradiating and projecting light onto the color filter substrate 10 by a light source 20 provided below the color filter substrate 10; b) detecting the intensity of transmitted light transmitted from the light source 20 through the color filter substrate 10 by a two-dimensional image detector 30 provided on the color filter substrate 10; c) image the intensity of the transmitted light detected by the 2D image detector 30 for each pixel 31 of the 2D image detector 30, wherein the color pattern 11 is formed inside the color pattern 11. An area corresponding to the color pattern 11 having the same shape as that of the color pattern 11 and smaller than the color pattern 11 is adopted as the pixel 31 of the 2D image detector 30 to correspond to each pixel 31. Calculating ratios of red, green, and blue according to the intensity of transmitted light, respectively; d) determining the failure of the color filter substrate using the calculated ratio; Print status inspection method of the color filter substrate, characterized in that comprises a. The method of claim 5, wherein And a pixel (31) of the two-dimensional image detector (30) is adopted with an area corresponding to 60 to 95% of the size of the color pattern (11). The method of claim 5, wherein The defects include color purity defects, color uniformity defects, overfilling of the color pattern 11 with an excessive amount of ink to cover adjacent color filters, and less ink filling the color pattern 11. The printing state inspection method of the color filter substrate, characterized in that the under filling (under filling). The method of claim 5, wherein A beam splitter positioned between the light source 20 and the color filter substrate 10 to separate some of the light irradiated from the light source 20 and to radiate the remaining light to the color filter substrate 10. 50 and a photodetector 60 for detecting the intensity of a portion of the light separated by the beam splitter 50, the transmitted light detected by the two-dimensional image detector 30 Adjusting and feeding back the intensity of light irradiated by the light source 20 when the intensity is less than or greater than a reference value; Print status inspection method of the color filter substrate, characterized in that further comprises. The method of claim 5, wherein Measuring chromaticity of each color pattern 11 of the color filter substrate; Obtaining a color ratio coordinate value of each color pattern 11 of the color filter substrate using the measured chromaticity value, the intensity data of the transmitted light detected in step b), and the color ratio value calculated in step c). ; Print status inspection method of the color filter substrate, characterized in that further comprises. The method of claim 9, Comparing the obtained color ratio coordinate values with actual color coordinate values to create a comparison correction table; Print status inspection method of the color filter substrate, characterized in that further comprises. The method of claim 5, wherein measuring a reference to establish a reference of the amount of transmitted light prior to step a); Print status inspection method of the color filter substrate, characterized in that further comprises.

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