KR101857086B1 - Defect detecting Device and Method the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device, Dividing the surface image into a first divided image and a second divided image; Measuring luminance of the first divided image to generate first luminance data; Measuring luminance of the second divided image to generate second luminance data; Generating luminance matching data by matching the first luminance data and the second luminance data; And detecting a defect of the liquid crystal display module using the brightness matching data. The method of claim 1,
According to the present invention, there is an effect of improving the defective detection power by reflecting the brightness difference of each pixel according to the inversion characteristic.

Description

[0001] The present invention relates to a liquid crystal defect inspection apparatus,

The present invention relates to a liquid crystal defect inspection apparatus, and more particularly, to a liquid crystal defect inspection apparatus capable of detecting defective liquid crystal of a liquid crystal display apparatus and a method of inspecting the same.

The liquid crystal display device displays an image by adjusting the light transmittance of liquid crystal having dielectric anisotropy using an electric field. To this end, the liquid crystal display device includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal panel.

Such a liquid crystal display device drives the liquid crystal panel by inversion driving method in order to prevent degradation of liquid crystal and improve display quality. Inversion driving methods include a frame inversion method, a line inversion method, and a dot inversion method.

In the dot inversion driving method, the polarities of the liquid crystal cells are opposite to those of the adjacent liquid crystal cells in the horizontal and vertical directions, and are inverted for each frame. Such a dot-in-version driving method provides excellent image quality as compared with other inversion driving methods by making flickers generated between adjacent liquid crystal cells in the vertical and horizontal directions cancel each other.

However, in the dot inversion driving method, since the polarity of the pixel voltage signal supplied from the data driver to the data line must be inverted in the horizontal and vertical directions, the variation of the pixel signal is larger than other inversion driving methods, There are disadvantages.

In recent years, in consideration of the power consumption aspect of such an inversion method, a data driver is driven by a column inversion driving method and a thin-film transistor (TFT) formed on a liquid crystal panel is arranged in a zigzag manner, The Z-inversion drive method has been introduced.

1 is a schematic view of a liquid crystal display panel for implementing a conventional Z-inversion driving method.

1, a liquid crystal display panel 10 for implementing a conventional Z-inversion driving method is defined as an intersection of a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm + 1. And a liquid crystal cell including a thin film transistor (TFT) and a pixel electrode 20 formed for each region to be formed.

The thin film transistor TFT supplies a data signal from the data lines DL1 to DLm + 1 to the pixel electrode 20 in response to a scan signal from the gate line GL. The pixel electrode 20 controls the transmittance of light by driving a liquid crystal positioned between the pixel electrode 20 and a common electrode (not shown) in response to a pixel signal. These liquid crystal cells are alternately connected to the different data lines DL adjacent to each other along the vertical direction through the thin film transistor TFT.

However, according to the liquid crystal defect inspection apparatus for inspecting the liquid crystal defects of the liquid crystal display device implemented by the above-described inversion driving method, there are the following problems.

First, there is a problem that defect detection is not easy due to a difference in brightness value between pixels due to non-uniformity of the bipolar data voltage and the negative polarity data voltage.

FIG. 2 is a view showing a surface image of a liquid crystal panel obtained in order to judge defective liquid crystal in a conventional liquid crystal defect inspection apparatus, and FIG. 3 is a diagram showing a data voltage for each pixel in FIG.

As can be seen from FIG. 2, it can be seen that the average luminance of the pixels constituting the surface image 30 is not uniform. That is, the average luminance of each of a plurality of pixels existing in the surface image 30 is not formed uniformly, but there is a difference in average luminance for each pixel.

As shown in FIG. 3, when the polarity of the data signal applied to the data line is inverted in units of frames, the difference in the average luminance of the data signal due to the voltage variation of the data signal due to polarity conversion It is caused by defective charging.

That is, when the negative polarity (-) data voltage of the voltage region lower than the common voltage Vcom after the first frame in which the positive polarity (+) data voltage in the voltage region higher than the common voltage Vcom is input is input to the second frame The liquid crystal pixels to which the first data voltage is input at the time of switching are charged with the abnormal data signal due to shortage of the charge time of the data signal according to the abrupt voltage variation Vmax so that the average luminance of the first horizontal pixel line of the liquid crystal display panel have.

Accordingly, such a difference in the average brightness of each pixel has a problem in that it is not easy to detect a defect such as a stain defect in an inspection apparatus that detects a difference in luminance in the surface image 30 and detects a defect.

In addition, there is a problem that a specific line of the surface image of the liquid crystal panel acquired by the liquid crystal defect inspection apparatus is blurred and mistaken as a defect.

FIG. 4 is a view showing that a specific line of a surface image of a liquid crystal panel is blurred, and FIG. 5 is a diagram showing that a voltage of a data signal is changed frame by frame.

As can be seen from FIGS. 4 and 5, during the inversion process, the voltage of the data signal changes abruptly, and when it is photographed, the specific line is photographed blurred. Therefore, in this case, there is a problem that a blurred specific line is mistaken as a defect.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal defect inspection apparatus and a method for inspecting a liquid crystal defect in which defect detection performance is improved in consideration of inversion characteristics.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a liquid crystal display; Dividing the surface image into a first divided image and a second divided image; Measuring luminance of the first divided image to generate first luminance data; Measuring luminance of the second divided image to generate second luminance data; Generating luminance matching data by matching the first luminance data and the second luminance data; And detecting a defect of the liquid crystal display module using the brightness matching data.

In this case, the dividing may include: dividing the surface image into regions where a plurality of rows and columns intersect; Dividing a first divided image made up of a sum of a region corresponding to an odd-numbered row of an odd-numbered column and an area corresponding to an even-numbered row of an even-numbered column in the surface image; And separating a second divided image including a sum of an area corresponding to an even-numbered row of an odd-numbered column and an odd-numbered row of an even-numbered column in the surface image.

The generating of the first luminance data and the second luminance data may include sampling the first column of the first divided image sequentially to extract a luminance value, sampling the next column sequentially, and extracting a luminance value A method of sampling the first luminance data by sampling one row in the second divided image in order to extract a luminance value and sampling the next column sequentially to extract a luminance value, .

According to another aspect of the present invention, there is provided a liquid crystal display comprising: an image acquiring unit acquiring a surface image of a liquid crystal display; An image processor for dividing the surface image into a first divided image and a second divided image; The first luminance data is generated by measuring the luminance of the first divided image, the second luminance data is generated by measuring the luminance of the second divided image, the first luminance data and the second luminance data are matched with each other, An image analyzer for generating matching data; And a defect detector for detecting a defect of the liquid crystal display module using the brightness matching data.

The image processing unit may divide the surface image into a plurality of regions where a plurality of rows and columns intersect each other. In the surface image, a sum of an area corresponding to an odd-numbered row in an odd-numbered column and an area corresponding to an even- And a second divided image including a sum of a region corresponding to an even-numbered row in an odd-numbered column and an odd-numbered row in an even-numbered column is transmitted to the image analyzer, To the analysis unit.

According to the present invention, the following effects can be obtained.

The present invention has the effect of improving the defective detection power by reflecting the difference in luminance per pixel according to the inversion characteristic.

Further, there is an effect of improving the defective detection power by reflecting the difference in luminance per pixel when the data voltage fluctuates according to the inversion characteristic.

1 is a schematic view of a liquid crystal display panel for implementing a conventional Z-inversion driving method.
2 is a view showing a surface image of a liquid crystal panel obtained for judging defective liquid crystal in a conventional liquid crystal defect inspection apparatus.
FIG. 3 is a diagram showing a data voltage per pixel in FIG. 2; FIG.
4 is a diagram showing that a specific line of the surface image of the liquid crystal panel is blurred.
5 is a diagram showing that the voltage of the data signal is changed frame by frame.
6 is a flowchart schematically showing a procedure of a liquid crystal defect inspection method according to the present invention.
7 is a view showing a surface image of the liquid crystal display device.
8 is a view showing a first divided image separated from the surface image of FIG. 7 by the liquid crystal defect inspection method according to the present invention.
9 is a view showing a second divided image separated from the surface image of FIG. 7 by the liquid crystal defect inspection method according to the present invention.
10 is a graph showing first luminance data and second luminance data generated by the method for inspecting a liquid crystal defect according to the present invention.
FIG. 11 is a graph showing luminance matching data generated by the liquid crystal defect inspection method according to the present invention.
12 is a view showing a surface image including a defective stain.
FIG. 13 is a view for calculating luminance matching data for the surface image of FIG. 12. FIG.
FIG. 14 is a view showing data obtained by inspecting the surface image of FIG. 12 by a conventional liquid crystal defect inspection method.
FIG. 15 is a view showing schematic components of a liquid crystal defect inspection apparatus according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal defect inspection apparatus and an inspection method thereof according to the present invention will be described in detail with reference to the drawings.

≪ Liquid crystal defect inspection method &

6 is a flowchart schematically showing a procedure of a liquid crystal defect inspection method according to the present invention.

As shown in FIG. 6, first, the surface image of the liquid crystal display device is acquired (S210). The acquisition of the surface image may be obtained using a camera, wherein one or more cameras may utilize a high-speed line scan camera.

Next, the surface image is divided into a first divided image and a second divided image (S220).

7 is a view showing a surface image of the liquid crystal display device, FIG. 8 is a view showing a first divided image separated from the surface image of FIG. 7, FIG. 9 is a view showing a second divided image Fig.

7 to 9, in order to divide the first divided image 210 and the second divided image 220 in the surface image 200, the surface image 200 is divided into a plurality of rows and columns It is divided into intersecting areas.

7, the surface image 200 is divided into six regions (P1 to P36) divided into six rows (C1 to C6) and six columns (R1 to R6).

Next, the first divided image 210, which is the sum of the area corresponding to the odd-numbered rows of the odd-numbered columns and the area corresponding to the even-numbered rows of the even-numbered columns, is separated from the surface image 200.

As can be seen from FIG. 8, the first segmented image 210 is composed of P1, P3, P5, P8, P10, P12, P13, P15, P17, P20, P22, P24, P25, P27, P29, P32, P36.

Next, a second divided image 220, which is a sum of an area corresponding to an even-numbered row of an odd-numbered column and an odd-numbered row of an even-numbered column, is separated from the surface image 200.

As can be seen in FIG. 9, the second divided image 220 is composed of P2, P4, P6, P7, P9, P11, P14, P16, P18, P19, P21, P23, P26, P28, P30, P31, P35.

Referring back to FIG. 6, the luminance of the first divided image is measured to generate first luminance data (S230).

In one embodiment, the first luminance data may be generated by sampling one column sequentially from the first divided image, extracting the luminance value, and sampling the next column sequentially to extract the luminance value. Also, the first luminance data may be generated by sampling one row in the first divided image in order, extracting the luminance value, and sampling the next row sequentially to extract the luminance value.

Next, the luminance of the second divided image is measured to generate second luminance data (S235).

In one embodiment, the second luminance data may be generated by sampling one column sequentially from the second divided image, extracting the luminance value, and sampling the next column sequentially to extract the luminance value. Also, the second luminance data may be generated by sampling one row in the second divided image in order, extracting the luminance value, and sampling the next row in order to extract the luminance value.

10 is a graph showing the first luminance data and the second luminance data.

As can be seen from FIG. 10, it can be seen that the first luminance data L 1 is repeatedly increased and decreased in a predetermined pattern. Also, it can be seen that the second luminance data L2 is repeatedly increased and decreased in a constant pattern. However, it can be seen that the first luminance data L1 and the second luminance data L2 have different peak values.

Referring again to FIG. 6, brightness matching data is generated by matching the first luminance data and the second luminance data (S240).

The luminance matching data may be generated by matching so that the periods and the average luminance of the first luminance data and the second luminance data are maintained within a predetermined error range.

FIG. 11 is a graph showing luminance matching data generated by the liquid crystal defect inspection method according to the present invention.

As can be seen from FIG. 11, the first luminance data L1 and the second luminance data L2 are matched similarly with the period and the luminance within a predetermined error range, unlike in FIG.

Referring again to FIG. 6, the liquid crystal defect of the liquid crystal display device is detected using the brightness matching data.

In one embodiment, the defect detection step determines that the luminance is out of order when the luminance between the predicted luminance data extracted from the luminance matching data and the luminance matching data exceeds a predetermined luminance difference.

That is, the luminance matching data has periodicity with a certain deviation as shown in FIG. 11, and the expected luminance data is generated based on the periodicity. The predicted luminance data refers to predicted average luminance data extracted based on the periodicity of luminance matching data.

Next, a luminance difference for judging defects based on the luminance matching data is set in advance, and a pixel having a luminance exceeding the luminance difference is judged as defective.

In the embodiment of the present invention, the step of discriminating defects has been described for generating and discriminating the predicted luminance data. However, the present invention is not limited to this, and the defects can be discriminated by various algorithms using the luminance matching data.

Hereinafter, a process of detecting defects using the liquid crystal defect inspection method according to the present invention will be described in detail.

12 is a view showing a surface image including a defective stain.

As can be seen from Fig. 12, the surface image 300 includes a stain defect (F). In order to explain the method of detecting this, the luminance matching data is calculated by using the liquid crystal defect inspection method according to the present invention along the lines L3 to L4.

FIG. 13 is a view for calculating luminance matching data for the surface image of FIG. 12. FIG.

As can be seen from FIG. 13, the luminance matching data shows that the luminance of the pixels corresponding to the lines L3 to L5 repeatedly rise and fall at a constant period.

At this time, it can be confirmed that the luminance value sharply decreases in the section corresponding to the stain defect (F). That is, it can be seen that the luminance of the section corresponding to the unevenness defect (F) is exceptional to the periodic characteristic of the luminance matching data.

That is, if the luminance of about 130 to 132 in FIG. 13 has a luminance characteristic according to the periodic characteristic, the luminance value of the F region has a value of about 125.

Therefore, if the luminance difference for detecting defects is set to about 4% (132 * 0.96 = 126.72), the F region has a luminance difference of about 5.3% (100-125 / 132 * 100) .

However, the method of discriminating defects by using the luminance difference is only an example, and the present invention is not limited thereto. Various algorithms can be used as algorithms for discriminating defects using the luminance matching data according to the present invention .

FIG. 14 is a view showing data obtained by inspecting the surface image of FIG. 12 by a conventional liquid crystal defect inspection method.

As can be seen from FIG. 14, unlike the brightness matching data according to the present invention, the brightness data inspected by the conventional liquid crystal defect inspection method is considerably complicated and the visibility is poor in discriminating the defect.

Therefore, the present invention has the effect of improving the defect detection capability by providing the brightness matching data reflecting the pixel difference per pixel according to the inversion characteristic.

<Liquid crystal defect inspection device>

Hereinafter, a liquid crystal defect inspection apparatus according to the present invention will be described in detail.

FIG. 15 is a view showing schematic components of a liquid crystal defect inspection apparatus according to the present invention.

15, the liquid crystal defect inspection apparatus 100 according to the present invention includes an image acquisition unit 110, an image processing unit 120, an image analysis unit 130, and a defect detection unit 140. As shown in FIG.

The image acquiring unit 110 acquires a surface image of the liquid crystal display device. The image acquiring unit 110 may include a camera capable of acquiring an image, a table storing a liquid crystal display device, and a driving unit capable of moving the camera or the table, though it is not shown specifically for acquiring an image.

The camera can use a high-speed line scan camera, and the number of cameras can be one or more.

The image processing unit 120 divides the surface image captured by the image obtaining unit 110 into a first divided image and a second divided image.

To this end, the image processing unit 120 divides the surface image into a region where a plurality of rows and a plurality of rows intersect, and a region corresponding to an odd-numbered row in an odd-numbered column and an even- Numbered rows of odd-numbered rows and odd-numbered rows of odd-numbered rows in the surface image, and transmits the first divided image composed of the sum of the first and second divided images to the image analysis unit 130. [ And transmits the second divided image to the image analysis unit 130.

The image analyzer 130 generates the first luminance data by measuring the luminance of the first divided image, generates the second luminance data by measuring the luminance of the second divided image, 2 luminance data to generate luminance matching data.

The image analyzer 130 generates the first luminance data by sampling one column sequentially from the first divided image, extracting a luminance value, sampling the next column sequentially, and extracting a luminance value. At this time, the first luminance data may be generated by sampling one row of the first divided image sequentially, extracting a luminance value, and sampling the next row sequentially to extract a luminance value.

The image analyzer 130 generates the second luminance data by sampling one column sequentially from the second divided image, extracting a luminance value, sampling the next column sequentially, and extracting a luminance value. At this time, the second luminance data may be generated by sampling one row in the second divided image in order to extract a luminance value, sampling the next row in order, and extracting a luminance value.

The image analyzer 130 generates the luminance matching data by matching the period and the average luminance of the first luminance data and the second luminance data so as to be maintained within a predetermined error range.

The failure detection unit 140 detects the failure of the liquid crystal display module using the brightness matching data.

In one embodiment, the failure detection unit determines that the brightness between the predicted brightness data extracted from the brightness matching data and the brightness matching data exceeds a predetermined brightness difference.

That is, the brightness matching data has periodicity with a certain deviation as shown in FIG. 11, and the defect detector 140 generates the predicted brightness data based on the periodicity. The predicted luminance data refers to predicted average luminance data extracted based on the periodicity of luminance matching data.

Next, the defect detector 140 determines that the predicted brightness data and the pixel whose brightness of the brightness matching data exceeds the brightness difference are defective, using the brightness difference which is a reference of the previously determined failure determination.

Therefore, the present invention has the effect of improving the defect detection capability by providing the brightness matching data reflecting the pixel difference per pixel according to the inversion characteristic.

In the embodiment of the present invention, the failure detector 140 generates the predicted brightness data to determine the failure. However, the present invention is not limited to this, and the failure can be determined by various algorithms using the brightness matching data .

It will be understood by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and from the equivalent concept are to be construed as being included in the scope of the present invention .

100 - Liquid crystal defect inspection system
110 -
120 -
130 - image analysis section
140 -

Claims (9)

Obtaining a surface image of a liquid crystal display device;
Dividing the surface image into a first divided image and a second divided image;
Measuring luminance of the first divided image to generate first luminance data;
Measuring luminance of the second divided image to generate second luminance data;
Generating luminance matching data by matching the periods and average luminance of the first luminance data and the second luminance data so as to be maintained within a predetermined error range; And
And detecting a defect of the liquid crystal display device using the brightness matching data. The method according to claim 1,
Wherein the dividing step comprises:
Dividing the surface image into regions where a plurality of rows and columns intersect;
Dividing a first divided image made up of a sum of a region corresponding to an odd-numbered row of an odd-numbered column and an area corresponding to an even-numbered row of an even-numbered column in the surface image; And
And dividing the second divided image into a sum of a region corresponding to an even-numbered row in an odd-numbered column and an odd-numbered row in an even-numbered column in the surface image. The method according to claim 1,
Wherein the generating of the first luminance data and the second luminance data comprises:
The first luminance data is generated by sampling one column in the first divided image in order to extract a luminance value and sampling the next column sequentially to extract a luminance value,
Wherein the second luminance data is generated by sampling one row in the second divided image in order to extract a luminance value and sampling a next column sequentially in order to extract a luminance value. delete The method according to claim 1,
The step of detecting the defect may include:
And detecting as a failure when the brightness between the predicted brightness data extracted from the brightness matching data and the brightness matching data exceeds a predetermined brightness difference. An image acquiring unit acquiring a surface image of a liquid crystal display;
An image processor for dividing the surface image into a first divided image and a second divided image;
The method of claim 1, further comprising: generating first luminance data by measuring luminance of the first divided image; measuring luminance of the second divided image to generate second luminance data; An image analyzer for matching the luminance so that the luminance is kept within a predetermined error range to generate luminance matching data; And
And a defect detector for detecting a defect of the liquid crystal display device using the brightness matching data. The method according to claim 6,
Wherein the image processing unit comprises:
The surface image is divided into a plurality of regions in which a plurality of rows and columns intersect each other,
Numbered rows of odd-numbered columns and odd-numbered rows of even-numbered columns in the surface image to the image analyzer,
Numbered rows of the odd-numbered rows and the sum of the odd-numbered rows of the even-numbered rows and the second divided image of the odd-numbered rows of the even-numbered columns to the image analyzer. The method according to claim 6,
Wherein the image analyzing unit comprises:
The first luminance data is generated by sampling one column in the first divided image in order to extract a luminance value and sampling the next column sequentially to extract a luminance value,
Wherein the second luminance data is generated by sampling one column sequentially from the second divided image to extract a luminance value and sampling the next column sequentially in order to extract a luminance value. The method according to claim 6,
Wherein the failure detecting section detects a failure when the brightness between the expected brightness data extracted from the brightness matching data and the brightness matching data exceeds a predetermined brightness difference.

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