JP3062711B2 - How to measure the brightness of the LCD panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the brightness of a liquid crystal display panel.

[0002]

2. Description of the Related Art Conventionally, as a lighting inspection of a liquid crystal display device, particularly a liquid crystal display device having a color filter, Japanese Patent Laid-Open Publication No.
As disclosed in JP-A-217817 or JP-A-3-53291, an image displayed on a liquid crystal display panel is measured by using a CCD camera, and the video signal is sent to an image processing device to perform binarization processing or patterning. A method is known by recognizing it. Of the above methods, the former is a method in which a dark spot inspection finds a lit pixel as a defective pixel in the same manner as a bright spot inspection, and the latter turns on a liquid crystal display panel to an intermediate brightness and removes a horizontal stripe defect that appears at that time. It is to detect.

[0003]

However, according to the former inspection method, defective pixels can be inspected because the non-defective pixels are not illuminated in both the dark spot inspection and the bright spot inspection, but the lighting luminance is measured. Can not do it. In the latter method, since the entire liquid crystal display panel is measured, if the relative position of the photocell to each display pixel is different, the degree of influence of the non-display area on each photocell will be different. In other words, each pixel is not measured under the same conditions, and the measurement accuracy is low. The present invention has been made in view of such a situation, and an object of the present invention is to provide a method for measuring the lighting luminance of a liquid crystal display panel with extremely high measurement accuracy.

According to the present invention, a lighting luminance of a liquid crystal display panel is controlled by a CC having a plurality of photocells arranged corresponding to each display pixel.
An image is taken by a D camera, the video signal is digitized, and taken into an image memory as lighting luminance data, and a photo corresponding to a black stripe portion in which scanning lines and signal lines are hidden.
Excludes cell measurements and the residual corresponding to each display pixel.
Rino is with a mean value of measured values of a plurality of photocells that without such a lighting luminance of each display pixel of the liquid crystal display panel.

[0005] In this case, it is preferable that the average value excludes lighting luminance data taken in from a photocell straddling the black stripe portion and each display pixel. Further, as described in claim 3, the liquid crystal display panel has R, G, B color filters for display pixels, and the measurement of the average value of the lighting luminance is performed as follows.
Lighting of at least two colors of R, G, and B and all of R, G, and B can be performed.

[0006]

According to the above method, the lighting luminance data taken in from the black stripe portion, which is a non-display area, is excluded when calculating the average value, so that the relative position of the photocell corresponding to each display pixel is determined. Irrespective of the measurement conditions being the same, the measurement of the lighting luminance can be performed with high accuracy. Ma
Also, measure the brightness of all display pixels with only one lighting
Therefore, the measurement operation can be made more efficient.

[0007] In this case, according to the second aspect, even when the photocell is located across the black stripe portion and each display pixel, it is possible to accurately measure the lighting luminance. Further, according to the third aspect, the present invention can be applied to the lighting luminance measurement of a liquid crystal display panel for full color display.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an apparatus for measuring lighting luminance and a circuit configuration according to the present invention. The inspection table 1 is slidable in two X and Y directions orthogonal to each other and rotatable in a horizontal rotation angle θ direction, and a liquid crystal display panel 5 is mounted on the upper surface thereof. The inspection table 1 is provided with an opening 1a at a portion corresponding to the display area of the liquid crystal. A backlight 2 is arranged below the inspection table 1, and light emitted from the backlight 2 is applied to the liquid crystal display panel 5 through the opening 1 a of the inspection table 1.

On the left and right sides of the inspection table 1, there are disposed an unloader 3 for removing the liquid crystal display panel 5 for which measurement has been completed from the inspection table 1, and a loader 4 for mounting the liquid crystal display panel 5 for new measurement on the inspection table 1. . A prober 6 connected to a connection terminal of the liquid crystal display panel 5 on the side of the inspection table 1 for lighting the liquid crystal display panel 5.
Is arranged.

[0010] Above the liquid crystal display panel 5, a CCD camera 7 in which photocells are arranged in a matrix is arranged to capture the lighting luminance of the liquid crystal display panel 5. CC
An image processing device 8 having an AD or AC converter 9, an arithmetic circuit 10, an image memory 11 and a display circuit 12 is connected to the D camera 7. All the members described above except the liquid crystal display panel 5 are integrally configured as one lighting luminance measuring device.

The liquid crystal display panel 5 will now be described. The liquid crystal display panel 5 is of an active matrix type for full-color display. Electrodes, a single transparent substrate on which a data line and a gate line connected to a gate electrode and a drain electrode of each thin film transistor are formed, and R arranged in a mosaic shape corresponding to each transparent pixel electrode;
Liquid crystal is sealed between G and B color filters and another transparent substrate on which a common electrode is formed.

On one transparent substrate of the liquid crystal display panel 5, a black stripe for blocking light emitted from the backlight 2 is formed opposite to the thin film transistor, the data line and the gate line. The CCD camera 7 has a built-in area-type photosensor, and a plurality of area-type photosensors are provided in the row direction and the column direction of the transparent pixel electrodes of the liquid crystal display panel 5, preferably three or more. The one corresponding to the photocell is used.

FIG. 2 shows the correspondence between the display pixels of the liquid crystal display panel 5 described above and the photocells of the CCD camera 7. R, G, and B are (red), G (green), and B (blue), respectively.
Are the corresponding transparent pixel electrodes, and each becomes one display pixel. The display pixels are X for R, G, and B.
The mosaic arrangement is alternately arranged in both directions. The periphery of each display pixel is surrounded by a black stripe BL. The black stripe BL shields a thin film transistor, a gate line, and a data line (not shown). The area type photosensor PS built in the CCD camera 7 has photocells S arranged in a matrix in the X direction and the Y direction. Three or more photocells S are arranged at a pitch corresponding to one display pixel in the X direction and the Y direction.

However, the pitch of the photocells S is not equal to the pitch of the display pixels. Therefore, as shown in FIG. 2, the position of the photocell S corresponding to each display pixel is different for each display pixel. For example, looking at the positional relationship between the photocell S corresponding to the display pixel R (referred to as R1) in the first row and the display pixel R (referred to as R2) in the second row, the display pixel R1 and the black stripe BL are straddled. Corresponding to the photocell S in the X1 column,
In the photocell S of the X10th column corresponding to the display pixel R2 and straddling the black matrix BL, the former is closer to the black matrix BL side.

Also, in the row direction, the photocells S in the Y1 row corresponding to the display pixel R1 are closer to the black stripe BL side than the photocells S in the Y7 row corresponding to the display pixel R2. As described above, if the relative position of the photocell S with respect to each display pixel is different, even if the display pixels R1 and R2 have the same lighting brightness, the cumulative sum of the lighting brightness obtained from the photocell S, and therefore, The measured values will be different.

Therefore, in the present invention, the lighting luminance from the photocell S at the position affected by the black matrix BL is excluded. In this case, it is desirable to exclude the lighting luminance data of the photocell S located at a position straddling the display pixel and the black stripe BL. As for the display pixel R1, the lighting luminance data from the photocell S located on the X1 and X5 columns or on the Y1 and Y5 rows is excluded, and the X2 and X5 columns are excluded.
It is located in the X3 column, the X4 column, and the Y2 row, the Y3 row,
Only the lighting luminance data of the nine photocells S located in the Y4th row are accumulated, and the average value is obtained. Similarly, for the other display pixels, the lighting luminance data from the nine photocells S at the positions corresponding to the entire display pixels are measured. With this configuration, the measurement conditions are the same, so that highly accurate measurement can be performed.

Next, the lighting luminance measuring method of the present invention will be described. In performing the inspection, the liquid crystal display panel 5 is supplied from the loader 4 onto the table 1 and set at a predetermined position. Then, a prober 6 is connected to the liquid crystal display panel 5 and a lighting signal is supplied. Lighting is performed for R lighting, G lighting, B lighting, and all lighting of RGB. However, the lighting order may be any order, and R, G,
If all lighting of B is performed, any one of R lighting, G lighting, and B lighting can be omitted.

Next, a CCD camera 7 arranged above the inspection table 1 captures an image of the entire display area of the liquid crystal display panel 5 and sends the lighting luminance as a video signal to the image processing apparatus. In the image processing device 8, the sent video signal is digitized by the AD or AC converter 9 and stored in the image memory 11 as lighting luminance data. This lighting luminance data is data that can be displayed in gradation.

Then, the image memory 11 is directly accessed by the arithmetic circuit 10, the contents stored in the image memory 11 are read out, and the average value of the lighting luminance is obtained. At this time, as described above, the lighting luminance data from the photocell S located entirely at the position corresponding to the display pixel is excluded, excluding the lighting luminance data from the photocell S at a position corresponding to even a part of the black stripe BL. only separation identified above of obtaining the cumulative meter sum is to calculate the average value. At this time,
If the display pixels of the more non-lighting the disconnection or short circuit, is immediately determined, displays a position of the defective display pixel via the display circuit 12.

The above-described lighting luminance measurement is performed for the entire display area of the liquid crystal display panel 5, an average value is calculated from the measured values of the respective display pixels, and the average value of each display pixel is compared with the average value of the entire display pixel. Inspection of display unevenness can be performed. The determination result of the display unevenness inspection can also be displayed via the display circuit 12. In this case, according to the present invention, since the measurement accuracy of each display pixel is high, the determination of the display unevenness inspection becomes extremely accurate and highly reliable.It is clear from the above description. In the present invention,
The smaller the pitch of the photocells S is, the better the measurement accuracy is, but the measurement time is lengthened in proportion to this. For this reason, three photocells S are provided for one side of each display pixel.
It is desirable to arrange about 5 pieces.

In the embodiment described above, the liquid crystal display panel 5 is set to a full color display.
The present invention can be applied to a monochrome display, and can be measured for a reflection type. The measurement result can be applied not only to the display / non-display inspection and the display unevenness inspection but also to various other inspections.

[0022]

As described above, according to the present invention, CC
High-precision lighting brightness of liquid crystal display panel using D camera
It can be measured with high efficiency .

[Brief description of the drawings]

FIG. 1 is a block diagram of a configuration of a measuring device for measuring the lighting luminance of a liquid crystal display panel according to the present invention.

FIG. 2 shows a display pixel and a CCD of the liquid crystal display panel shown in FIG.
FIG. 3 is a plan view for explaining a relative positional relationship between photocells constituting an area-type photosensor built in a camera.

[Explanation of symbols]

1 inspection table 5 liquid crystal display panel 7 CC
D camera 8 Image processing device 11 Image memory BL Black stripe S Photo cell

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masanori Akita 1-1-45 Oe, Otsu City, Shiga Prefecture Toray Engineering Co., Ltd. (56) References JP-A-4-133088 (JP, A) JP-A-3-217817 (JP, A) JP-A-4-305622 (JP, A) JP-A-4- 244931 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/13 101 G01M 11/00 G02F 1/1343 G09F 9/00 G01N 21/84

Claims (3)

(57) [Claims] 1. A lighting brightness of a liquid crystal display panel is imaged by a CCD camera in which a plurality of photocells are arranged corresponding to respective display pixels, and a video signal thereof is digitized and taken into an image memory as lighting brightness data and scanned. Excluding the measurement of the photocells corresponding to the black stripe portion that concealed the lines and the signal lines, each display pixel of the liquid crystal display panel has an average value of the measurement values of the remaining plurality of photocells corresponding to each display pixel. A lighting luminance measurement method for a liquid crystal display panel. 2. The liquid crystal display panel according to claim 1, wherein the average value excludes lighting luminance data taken in from a photocell straddling a black stripe portion and each display pixel. Lighting luminance measurement method. 3. The liquid crystal display panel has R, G, and B color filters for display pixels, and the average value of the lighting luminance is measured by at least two of R, G, and B.
2. The method according to claim 1, wherein the method is performed for lighting of all colors, R, G, and B.