KR101876908B1 - Enhancement method for location accuracy of display panel defect - Google Patents

Abstract

The present invention relates to a method for improving positional accuracy of a defect of a display panel. More specifically, the present invention relates to the method capable of obtaining an image by radiating a background light source to a display panel, dividing the obtained image into several images in vertical and horizontal directions, identifying a display panel region in the divided images, determining whether defects exist in all pixel units included in the identified display region, and accurately calculating and displaying a position based on the edge of the display panel with respect to determined defects.

Description

TECHNICAL FIELD [0001] The present invention relates to a display panel,

The present invention relates to a method of improving the accuracy of a defect position of a display panel, and more particularly, to a method of improving the accuracy of a defect position of a display panel by acquiring an image by irradiating a background light source with a display panel, A method of determining whether or not a defect exists in all the pixel units included in the identified display area and accurately calculating and displaying the position based on the edge of the display panel with respect to the determined defects .

A general manufacturing process of a display panel will be briefly described. A TFT process for manufacturing a TFT glass by forming an electrode in a glass, a CF process for forming a CF glass by depositing R, G and B sensitizing liquid on a glass, A cell process in which a TFT glass and a CF glass manufactured by a CF process are bonded to each other and a liquid crystal is injected and sealed therebetween, and a module process in which a polarizing film and a PCB are combined with a panel manufactured in the cell process, Lt; / RTI >

In the process of manufacturing the display panel, many tests are performed in the intermediate process to prevent the defective panel from proceeding to the final stage and to improve the cause of the defective panel and the real time process. Accordingly, it is possible to increase the yield and improve the reliability of the product by reducing the defective rate of the product by proceeding to the next step by recognizing and discarding the defective panel in the intermediate manufacturing process or repairing the defect.

Accordingly, various methods for detecting defects in the display panel have been developed, and as a technique for inspecting the defects of the display panel, a method of inspecting a pixel defect in a display panel using image processing is disclosed in Patent Publication No. 10-1068356.

The method includes the steps of acquiring an image of a display panel using a line scan camera capable of capturing each pixel unit in a display panel with A × B scan pixels, analyzing brightness values of the respective scan pixels in the image, Dividing a boundary between a display panel pixel region formed with the scan pixels and a background region formed with scan pixels less than the threshold value, and a step of searching for center points having a maximum brightness value in each row direction of the scan pixels located within the display panel pixel region Determining a center position in the X direction of the pixel and a center position in the specific column direction as a center position in the Y direction, and determining the center coordinates x, y of each pixel; , A rectangle region having A × B scan pixels centered on the center coordinate is finally determined as a pixel portion And calculating the individual brightness characteristic values of the respective pixels determined within the display panel and comparing the individual brightness characteristic values with the average brightness characteristic values calculated for all the pixels to determine whether or not each pixel is defective.

In addition, the above technique has an advantage in that it is possible to check whether individual pixels of the display panel are defective. However, it is possible to determine a specific column direction in which the center points are most arranged as a center position in the X direction of the pixel, The center position of the brightness distribution is not detected in the presence of a defect, or the value of the brightness distribution changes.

However, the above-mentioned prior art is not a method of calculating the position of a defect, but it is a check of the presence or absence of a defect of the display panel, which can identify the defect itself but can not identify the defect position.

On the other hand, among the existing methods for calculating the positions of defects in the display panel, a grid check box pattern is irradiated on the display panel, and the image position points for the edges of the check box pattern are photographed, In the intermediate process for fabricating the display panel, since the common electrodes for connecting the plurality of pixels are bound together, the application of the signal through the common electrode is locally limited Therefore, it is impossible to apply a check box pattern of a complicated shape, and there is a problem that the position of the defect of the panel can not be confirmed by the check box pattern method.

KR 10-1068356 B1 (September 21, 2011)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide an image display apparatus and a display method thereof, The display panel region is identified in each of the divided images, the display panel image is binarized to calculate the center point of the pixel unit, the coordinates are sequentially given to the calculated center point, And correcting the defective pixel position of the pixel unit.

According to an aspect of the present invention, there is provided a method of improving accuracy of a defect position of a display panel, including: capturing an image of the display panel using a camera of a photographing unit; An image segmenting step of segmenting an image into a plurality of images in a horizontal direction and a vertical direction based on a difference in image brightness distribution in the image captured at the imaging step; A binarization step of performing image processing for each of the divided areas in the image segmenting step; A center point calculation step of calculating a center point of the pixel unit through the binarization processing step; A coordinate allocating step of sequentially assigning pixel unit coordinates to the center points calculated in the center point calculating step; And a defective pixel unit display step of displaying the coordinates of the pixel unit determined to be defective in the coordinate allocation step.

Here, the coordinates assigned in the coordinate allocation step are set as the reference point at the corner of the display panel in the area of the image information, and are sequentially counted in the plane coordinates of the X axis and the Y axis with respect to the pixel units of the display panel, .

In addition, the defect detected in the defect detecting step may be determined as a defect when the center point of the pixel unit can not be calculated.

According to the present invention, the position of the defective pixel unit can be accurately counted from the reference point in the display panel.

In addition, since a check box pattern can be used in a manufacturing process of a display that can not illuminate a panel, it is possible to minimize the defective rate of a finally manufactured product, There are advantages that can be easily applied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram of a defect position detection system to which a defect position accuracy improvement method for a display panel according to the present invention is applied. FIG.
2 is a flow chart of a method for improving the accuracy of a defect position of a display panel according to the present invention.
3 is a diagram showing image information of a display panel photographed by a photographing unit in a method of improving accuracy of a defect position of a display panel according to the present invention.
FIG. 4 is a flowchart illustrating a method of detecting a center point in a method for improving accuracy of a defect position of a display panel according to the present invention.
5 is a view showing a binary image in a method of improving the accuracy of a defect position of a display panel according to the present invention.
6 is a view showing coordinate positions of a center point in a method of improving accuracy of a defect position of a display panel according to the present invention.
FIG. 7 is a diagram illustrating coordinates of a divided area based on a center point in a method of improving accuracy of a defect position of a display panel according to the present invention. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to an image display apparatus, an image display method, a display method, a program, and a program, which are capable of acquiring an image by irradiating a background light source with a display panel, dividing the acquired image into a plurality of images in the horizontal and vertical directions, To determine whether or not a unit is defective, and to accurately calculate and display the position of the determined defects with reference to the edge of the display panel.

1 is a schematic block diagram of a defect position detection system to which a defect position accuracy improvement method for a display panel according to the present invention is applied.

Referring to FIG. 1, the defect position detection system includes a backlight unit 10, a photographing unit 20, and a defect confirmation display unit 30.

The backlight unit 10 is positioned below the display panel 100 and irradiates the display panel with a light source, and a polarizing film 10A is attached to the upper surface thereof.

At this time, the polarizing film 10A performs a function of outputting a light source that is incident while being vibrated in various directions as light that vibrates only in one direction.

The light source module included in the backlight unit 10 may be disposed in a zigzag manner to irradiate a uniform light source.

As the light source module, a cold cathode fluorescent lamp or an external electrode fluorescent lamp may be used. Depending on the design conditions, the light source module may also be a light emitting diode (LED).

On the other hand, a display panel 100, which is an object to be inspected, is disposed above the backlight unit 10.

The display panel 100 includes a CF glass 110, a lower TF glass 120, and a liquid crystal 130 interposed therebetween.

A color filter 112, a black matrix 113, a common electrode 114, and an alignment film 115 are formed on the upper substrate 111 of the CF glass 110.

A TFT array 122, a pixel electrode 123 and an alignment film 124 are formed on the lower substrate 121 of the TFT glass 120

The photographing unit 20 acquires an image of image information using a camera at an upper portion of the display panel. The camera captures the entire display panel or acquires an enlarged image by dividing the display panel into four So as to acquire a divided image.

At this time, the photographing unit 20 is provided with a polarizing film 20A1, and transmits the specified polarized light component and absorbs the unspecified polarized light component.

Here, the pixel unit used for the image photographed by the camera of the photographing unit 20 is enlarged / reduced by the resolution of the camera and the lens magnification.

In addition, the camera may be configured as an area image sensor that images a two-dimensional plane.

The defect check display unit 30 receives the image captured by the photographing unit 10 and calculates and displays the position of the defective pixel unit based on the received image. The defect check display unit 30 includes a processor for executing the set logic, A memory, an input / output device, a graphic interface, and a communication device, and a defect checking program installed in the terminal to calculate a defect location.

Hereinafter, a method for improving the accuracy of the defect position of the display panel in the defect confirmation display unit 30 will be described.

2 is a flowchart illustrating a method for improving the accuracy of a defect position of a display panel according to the present invention.

Referring to FIG. 2, a defect position accuracy improvement method for a display panel according to the present invention includes an imaging step S10, an image segmentation step S20, a binarization processing step S30, a center point calculation step S40, A step S50 and a defective pixel unit display step S60.

1. Step of photographing (S10)

The photographing step S10 is a step of photographing an image of the display panel using the camera of the photographing unit 20 (see Fig. 1).

At this time, the entire area of the display panel is photographed or at least one edge (edge) is photographed so that a reference point can be set in the photographed image.

2. Image segmentation step (S20)

The image segmenting step S20 identifies the area of the display panel in the image photographed in the photographing step S10 and divides the area of the image horizontally and vertically in order to minimize the brightness distribution difference of the identified display area .

At this time, the number of divided areas may be configured to limit the divided area based on the set number of divisions. For example, when the number of divided areas of an image is set to 100 x 100, a divided area consisting of 100 lines and 100 lines in the image area may be set and the remaining area may not be divided. Therefore, there is an advantage that the designated area can be intensively examined.

Here, the pixel unit means a set of pixels consisting of R (red), G (green) and B (blue) as a minimum unit repeated in the display panel.

In general, a pixel (pixel) is formed into a rod shape having R, G, and B values, which means a small dot which is a unit constituting a pixel.

The CF glass is manufactured through a complicated process, but roughly, a black matrix pattern is formed on the glass, and then a red sensitizing solution, a green sensitizing solution and a blue sensitizing solution are sequentially deposited, and a transparent electrode (ITO, Indium-Tin Oxide) , And the pixel unit in the present invention means one aggregate of R (red), G (green) and B (blue) combined with three pixels.

3 is a view showing an image of a display panel taken by a photographing unit in a method of improving accuracy of a defect position of a display panel according to the present invention.

When the display panel is photographed with a camera from above with the light source being irradiated on a part of (or a part of) the display panel, the image brightness of the G pixel is the brightest and the brightness of the R pixel is the darkest .

That is, it is possible to distinguish between the adjacent pixel units according to the brightness difference between the pixel units 21, which is an aggregate of R, G, and B (22) in the photographed image. Also, because of the block matrix of the CF display panel, it is possible to distinguish between upper and lower pixel units. That is, the brightness distribution of the adjacent pixel units between the right and left and the top and bottom by the brightness.

3. Image Processing Step (S30)

The image processing step S30 is an image processing step for each of the images divided in the image dividing step.

4 is a flowchart illustrating an image processing process in a defect position accuracy improvement method of a display panel according to the present invention.

Referring to FIG. 4, the center point detection step S30 includes a binarization threshold calculation step S31, a binarization step S32, and a center detection step S33.

3-1. In the binarization threshold calculation step S31,

The binarization threshold calculation step S31 is a step of calculating a binarization threshold value for binarizing the area of the display panel in the divided image and identifying the area of the pixel unit in the display panel area.

Binarization of an image is an effective image segmentation method for dividing an image into a display panel and an image background, and is a process of converting complex information possessed by a camera taken by a photographing unit into a shortened amount of information required in the present invention.

That is, the binarization of an image means that all the pixels in the image are represented by black and white (0 and 1). The binarization is based on a threshold value calculated for an image having a value of 0 to 255 on an 8- 0 < / RTI > is assigned to the pixel value, and 1 is added to the threshold value to process each pixel in black and white. Here, the pixel is the minimum unit of the image captured and acquired by the camera.

In this case, the method of binarizing image information may be selected from global binarization or local binarization, but in the present invention, the captured image is divided into a plurality of images, and one threshold value is applied to each image The local binarization method is applied. Here, the threshold value can be configured to be adjustable by the maximum brightness value, the minimum brightness value, the brightness variance value, and the user's setting input value in each divided image.

That is, in the present invention, the threshold value for performing binarization is calculated by calculating the average brightness value of the maximum brightness value and the minimum brightness value in each pixel in the divided region on the assumption that the pixels of the divided region are n x m, And a brightness value of each pixel to calculate a brightness variance value, and then subtracting a constant value (user input value) from the calculated brightness variance value.

Since the threshold value according to the binarization process is calculated according to the surrounding brightness value at the time of image capturing and the input value of the user, the threshold value calculation method has an advantage of calculating an optimal threshold value for performing the binarization .

3-2. Binarization step by region (S32)

The per-binarization step S32 is a step of binarizing the image of the corresponding region according to the binarization threshold value calculated in the binarization threshold calculation step.

The binarization method applied to the present invention divides the image information into a plurality of regions and applies different threshold values to each region to binarize the image information. FIG. 5 illustrates a method of improving the accuracy of a defect position of a display panel according to the present invention. FIG.

This method of processing an image by binarization has the advantage of simplifying computational complexity. For example, in the case of 24-bit RGB image information, it has a value of 24 bits per pixel, which includes 0 to 16,777,216 (approximately 16 million) information. However, when the image information is binarized, This is possible.

3-3. Step S33 of deriving the center by region

The center-by-area detection step S33 is a step of deriving the center of each pixel unit binarized for each area in the binarization step for each area.

In Fig. 5, the red region indicates a detection region for a G pixel (dot) of a pixel unit existing in the display panel.

4. Calculating the center point (S40)

The center point detection step S40 is a step of finally calculating the center point of the center point based on the center of the G pixel derived from the image segmented in the binarization step S30.

FIG. 6 is a view showing a coordinate position of a center point in a method of improving the accuracy of a defect position of a display panel according to the present invention.

At this time, if there is a defect in the display panel, the pixel units in the defective part can not calculate the center point.

That is, if a defect is generated in the process of calculating the center point based on the G pixel detected at the center, the center point can not be calculated. If it is determined that the center point is not calculated, it is determined that the defect is a defect of the pixel unit.

Also, when the center point of the G pixel is compared with the neighboring center points and the center point of the G pixel is not located on the straight line with the neighboring center points, it is determined that the pixel unit is a position defect. In other words, the position defect of the pixel unit is calculated based on the positional information of the adjacent center points.

Thus, when it is determined that the pixel unit is missing or the pixel unit position is defective, the information is displayed.

According to the design conditions, it may be configured to recalculate for accuracy if it is determined that the pixel unit is missing or a pixel unit position defect is determined.

5. Coordinate allocation step (S50)

The coordinate allocation step S50 is a step of assigning coordinates to the center point calculated in the center point calculating step S40.

The order of the coordinates allocated in the coordinate allocation step may be sequentially allocated from a reference point (for example, a corner) determined as a display area. At this time, the reference point can be selected as an edge existing in the image from among the upper left, upper right, lower left, or lower right corner determined as the display area in the photographed image, and (0, 0), (1, 1) (n, m) in that order.

FIG. 7 is a diagram illustrating coordinates of a divided area based on a center point in a method of improving accuracy of a defect position of a display panel according to the present invention.

Here, referring to FIG. 6, one point is displayed with respect to the center point of each pixel unit, and the displayed points have a structure arranged horizontally and vertically.

6, each of the points has coordinates of one pixel unit. In the image photographed on the upper left side as shown in FIG. 6, the uppermost left coordinate is set to (0, 0) Coordinates are assigned in the order of (1, 0) and (2, 0) on the ordinate and coordinates are assigned in the order of (0, 1) and (0, 2) on the basis of (0, 0).

Coordinates can be assigned to all pixel units with respect to an image photographed in this manner.

6. Defective pixel unit display step (S60)

The defective pixel unit display step S60 is a step of displaying accurate position coordinates with respect to the defective pixel units allocated in the coordinate allocating step S50. In addition, it is determined that there is a pixel unit in which a center point can not be found in the coordinate allocating step (S50), and it is recognized as a defect.

According to the present invention, there is an advantage that the position of a pixel unit in which a defect exists can be confirmed and a position error can be eliminated by separately analyzing the defect detection and the defect position calculation for the pixel unit in the divided image.

In addition, since this method can be used in an intermediate process in which a check box pattern can not be illuminated on a panel, it is possible to minimize the defective rate of the finally manufactured product, and the apparatus according to the inspection is simple, There are applicable advantages.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: Display panel
10: backlight unit
20:
30:

Claims (3)

A defective pixel unit is detected based on a backlight unit for irradiating a light source at a lower portion of the display panel, a photographing unit for acquiring an image using a camera at an upper portion of the display panel, and an image acquired by the photographing unit, A method for improving fault location accuracy,
An imaging step of acquiring an image such that the entire area or at least one corner of the display panel is photographed using the camera of the photographing part;
An image segmenting step of segmenting an image into a plurality of images in a horizontal direction and a vertical direction based on a difference in image brightness distribution in the image captured at the imaging step;
A binarization step of performing image processing for each of the divided areas in the image segmenting step;
A center point calculation step of calculating a center point of the pixel unit through the binarization processing step;
A coordinate allocating step of sequentially assigning pixel unit coordinates to the center points calculated in the center point calculating step; And
A defective pixel unit display step of displaying pixel unit coordinates determined as a defect in the coordinate allocation step;
And,
The threshold value for performing the binarization in the binarization processing step may be, for example,
The average brightness value of the maximum brightness value and the minimum brightness value is calculated for each pixel in the divided region, and the brightness variance value is calculated using the average brightness value and the brightness value of each pixel. Then, a constant is calculated from the calculated brightness variance value Lt; / RTI >
Wherein the threshold value is configured to be adjustable according to a maximum brightness value, a minimum brightness value, a brightness variance value, and a set input value of a user in each divided image,
The coordinate assigned in the coordinate allocation step may be,
A corner located in the image among the upper left, upper right, lower left, or lower right corner of the display panel in the divided region is set as a reference point, the pixel units of the display panel are sequentially counted in the plane coordinates of the X axis and the Y axis, Lt; / RTI >
The defects detected in the defective pixel unit display step include:
And determining that the center point of the pixel unit can not be calculated as a defect.
delete delete

Images