JP2013015868A - Panel evaluation system and panel evaluation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel evaluation system and a panel evaluation method for exactly evaluating a display panel in an adjustment process of the display panel.SOLUTION: A control part 21 of an image quality adjustment device 20 turns backlight of a liquid crystal panel 10 for adjustment OFF to execute determination processing about whether or not there is reflection. When it is determined that there is the reflection, the control part 21 executes error processing. When it is determined that there is no reflection, unevenness elimination adjustment is started, measurement processing, and correction data generation processing are executed. When it is determined that there is fluctuation in brightness during measurement, the control part 21 executes the error processing. On the other hand, when adjustment is terminated, correction data is written in a correction circuit 50.

Description

  The present invention relates to a panel evaluation system and a panel evaluation method for evaluating a display panel in a display panel adjustment process.

  Today, a production line for a display such as a liquid crystal panel is constructed so as to realize uniform quality. However, even in such a production line, manufacturing variations occur in individual displays. Therefore, a technique for adjusting each display so that a better image can be output has been studied (for example, see Patent Document 1). In the technique described in Patent Document 1, the control unit of the image quality adjustment device generates a test pattern, supplies the test pattern to the liquid crystal panel, and acquires an output image from the photographing camera. Then, bandpass filtering is performed on the output image data to calculate a correction value. When the calculation of the image correction table is completed for all the reference gradations, it is written in the ROM of the correction circuit. For an image signal for displaying an image on the liquid crystal panel, a linearly interpolated correction value is calculated with reference to an image correction table recorded in the ROM.

JP 2010-57149 A (first page, FIG. 1)

  As described in the patent document, it is necessary to take an image displayed on the liquid crystal panel in order to generate correction data. However, there may be a case where illumination of the measurement area is reflected on the liquid crystal panel during photographing. When such external light is photographed together with the display image, there is a problem that accurate correction data cannot be created.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a panel evaluation system and a panel evaluation method for accurately evaluating a display panel in a display panel adjustment process. .

  In order to solve the above problems, the invention described in claim 1 supplies an image signal to be displayed on the display panel and obtains a measured value from a measuring means for measuring the luminance of each pixel displayed on the display panel. A panel evaluation system including a control means for controlling the brightness of the display panel from the measurement means to supply a backlight turn-off instruction to the display panel. If the measured value is equal to or greater than a reference value, a stop instruction for measuring the luminance unevenness of each pixel is output. If the measured value is less than the reference value, the luminance unevenness of each pixel is measured. A display panel measurement process for supplying the display panel with an image signal for measuring the luminance corresponding to the image signal by the measurement means.

  According to a second aspect of the present invention, in the panel evaluation system according to the first aspect, an instruction to turn off the backlight is supplied before the start of the display panel measurement process, and the measured luminance value is the reference value in the backlight off state. The gist of the above case is to output an instruction to stop measuring the luminance unevenness of each pixel.

  According to a third aspect of the present invention, in the panel evaluation system according to the first or second aspect, when the same image signal is supplied to the display panel in the measurement of the luminance unevenness of each pixel, When changing is detected, the gist is to output an instruction to stop measuring the luminance unevenness of each pixel.

  According to a fourth aspect of the present invention, in the panel evaluation system according to the third aspect, when a luminance variation is detected in the same image signal, the measurement result in a predetermined range is reset, and the image signal in this range is reset. Is supplied again to the display panel and remeasured.

  The invention according to claim 5 is a panel evaluation system provided with a control unit that supplies an image signal to be displayed on the display panel and obtains a measurement value from a measurement unit that measures the luminance of each pixel displayed on the display panel. The control means supplies a backlight turn-off instruction to the display panel, and the measuring means supplies the luminance in the backlight-off state. A step of obtaining a measurement value, and when the measurement value is equal to or greater than a reference value, outputs an instruction to stop measuring the luminance unevenness of each pixel. When the measurement value is less than the reference value, the luminance unevenness of each pixel is measured. The gist of the present invention is to supply an image signal to the display panel, and to perform a display panel measurement process for measuring the luminance corresponding to the image signal by the measuring means.

(Function)
According to the first or fifth aspect of the invention, the control means supplies a backlight turn-off instruction to the display panel, and acquires a measured value of luminance in the backlight-off state from the measurement means. If the measured value is greater than or equal to the reference value, an instruction to stop measuring the luminance unevenness of each pixel is output. On the other hand, if it is less than the reference value, an image signal for measuring the luminance unevenness of each pixel is supplied to the display panel, and a display panel measurement process for measuring the luminance corresponding to this image signal is executed by the measuring means. . Thereby, it is possible to prevent reflection of outside light other than light emission of the original luminance of the display panel, and to generate accurate correction data corresponding to luminance unevenness.

  According to the second aspect of the present invention, an instruction to turn off the backlight is supplied before the start of the display panel measurement process, and when the measured luminance value is equal to or higher than the reference value in the backlight turned off state, Outputs an instruction to stop measuring uneven brightness. Thereby, when there is a problem of external light, it can be stopped before the start of measurement.

  According to the third aspect of the present invention, when the variation in luminance is detected when the same image signal is supplied to the display panel in the measurement of the luminance unevenness of each pixel, the luminance of each pixel is detected. Outputs instructions to stop uneven measurement. Thereby, even when external light is detected during measurement of luminance unevenness, the measurement can be stopped.

  According to the fourth aspect of the present invention, when a luminance variation is detected in the same image signal, the measurement result in a predetermined range is reset, and the image signal in this range is supplied again to the display panel, Measure. Thereby, even if a problem is detected, it can be re-measured efficiently.

  According to the present invention, the display panel can be accurately evaluated in the adjustment process of the display panel.

Explanatory drawing of the panel evaluation system of this invention. Explanatory drawing of the process sequence of this invention.

  Hereinafter, the panel evaluation system and the panel evaluation method of the present invention will be described. In the present embodiment, it is assumed that image quality is improved by suppressing display unevenness (brightness unevenness) of the display panel to be adjusted. In the present embodiment, the liquid crystal panel 10 is used as a product to be adjusted (display panel).

  The liquid crystal panel 10 includes a liquid crystal (liquid crystal unit) sandwiched between transparent electrodes and a backlight that illuminates the liquid crystal from the back. For this reason, the liquid crystal panel 10 outputs an image in which the unevenness of the liquid crystal part and the peripheral light reduction of the backlight are superimposed.

  Therefore, in order to improve the image quality of the liquid crystal panel 10, the liquid crystal panel 10 includes a correction circuit 50 for adjusting the supplied image signal as shown in FIG. Specifically, an image signal (RGB signal) for displaying an image on the liquid crystal panel 10 is supplied to the correction circuit 50 together with the liquid crystal panel 10.

The correction circuit 50 includes a nonvolatile memory (ROM 51) for recording an image correction table.
This ROM 51 stores data (image correction table) relating to correction values for adjusting the signal value of the input image signal. In the present embodiment, a planar distribution of correction values is stored for each reference gradation.

As shown in FIG. 1, the correction circuit 50 includes a selection / interpolation unit 52 and an addition unit 53 in addition to the ROM 51.
The selection / interpolation means 52 refers to the image correction table recorded in the ROM 51 for each RGB signal. Here, the selection / interpolation means 52 is a correction determined by four block grid points surrounding the pixel position (xy coordinate) of the image signal in the image correction table of two reference gradations adjacent to each RGB signal value of the image signal. A value (2 × 4 = 8) is acquired. Then, the selection / interpolation means 52 performs linear interpolation on the acquired correction value according to the distance between the signal value of the image signal and each grid point.
The adding unit 53 adds the correction value acquired from the selecting / interpolating unit 52 to the input image signal. The liquid crystal panel 10 acquires the corrected image signal and displays an image.

  As shown in FIG. 1, the panel evaluation system for calculating the correction value includes an image quality adjustment device 20, a photographing camera 30, a test pattern generation device 31, and a ROM writer 32. In the present embodiment, the liquid crystal panel 10 to be adjusted and the photographing camera 30 are installed in a measurement area A that is a dark room where outside light is shielded.

The image quality adjustment device 20 is connected to a photographing camera 30, a test pattern generation device 31, and a ROM writer 32.
Here, the photographing camera 30 as a measuring unit photographs an image displayed on the liquid crystal panel 10 and supplies output image data to the image quality adjustment device 20. In the present embodiment, a monochrome camera including a CCD element that can resolve an area smaller than the pixel size of the display panel is used as the photographing camera 30. Then, the image displayed on the liquid crystal panel 10 is taken.

A test pattern generation device 31 as a signal generation unit supplies a test pattern signal to the liquid crystal panel 10 based on an instruction from the image quality adjustment device 20. In the present embodiment, 8-bit RGB signals are supplied to the entire surface of the liquid crystal panel 10.
The ROM writer 32 writes the image correction table in the ROM 51 of the liquid crystal panel 10 to be adjusted.

  The image quality adjustment device 20 is a computer terminal that executes processing for calculating a correction value for adjusting the image quality of the liquid crystal panel 10. The image quality adjustment apparatus 20 includes a control unit 21, a correction information storage unit 22, and a display. This display is used by the manager of the adjustment process of the liquid crystal panel 10 to check the adjustment status and the like.

  The control unit 21 includes a CPU, a RAM, a ROM, and the like as control means, and performs processing described later (processing including a management stage, a correction data generation stage, an external light monitoring stage, and the like). By executing the correction data creation program for this purpose, the control unit 21 functions as a management unit 211, a correction data generation unit 212, and an external light monitoring unit 213.

  The management unit 211 executes a process for managing the adjustment process of the liquid crystal panel 10. Specifically, an instruction to turn off the backlight, a measurement start instruction to the test pattern generator 31, an instruction to write correction data to the ROM writer 32, and the like are supplied. On the other hand, when a problem is detected in the adjustment process, a measurement stop instruction is output.

  The correction data generation unit 212 executes processing for generating correction information corresponding to the characteristic information of the adjustment target product. Specifically, a correction value is calculated based on an image displayed on the liquid crystal panel 10, and an image correction table configured by the calculated correction value is recorded in the correction information storage unit 22.

  The external light monitoring unit 213 executes processing for determining whether the measurement area A is an environment suitable for measurement. Specifically, it is determined whether or not external light has entered the measurement area A before the start of measurement or when measuring the luminance unevenness of each pixel. This outside light includes not only light entering from outside the measurement area A but also illumination in the measurement area A and the like.

  The correction information storage unit 22 stores correction data (image correction table) for correcting the image of each liquid crystal panel 10. This correction data is registered when an image correction table is acquired from the image quality adjustment apparatus 20. The correction information storage unit 22 temporarily stores correction data (image correction table for suppressing display unevenness for each predetermined gradation) to be written in the ROM 51 of the liquid crystal panel 10.

  The display of the image quality adjustment device 20 is used by an administrator of the adjustment process of the liquid crystal panel 10 to check the adjustment status and the like. Specifically, a message is output to this display when error processing described later is performed.

The process (FIG. 2) which performs panel evaluation of the liquid crystal panel 10 using said system is demonstrated.
(Correction data generation process)
The correction data generation process is performed using the image quality adjustment device 20.

  First, the control unit 21 of the image quality adjustment apparatus 20 performs a panel detection process (step S1). Specifically, the pallet on which the liquid crystal panel 10 is mounted is carried into the measurement area A. Then, the test pattern generator 31 and the ROM writer 32 are connected to the liquid crystal panel 10. Furthermore, the photographing camera 30 is disposed in front of the liquid crystal panel 10. Then, the processing start is input to the image quality adjustment device 20. In this case, the management unit 211 of the control unit 21 confirms whether or not the test pattern generator 31 and the ROM writer 32 are connected to the liquid crystal panel 10, and if connected, starts measurement.

  Next, the control unit 21 of the image quality adjustment apparatus 20 performs a backlight OFF process (step S2). Specifically, the management unit 211 of the control unit 21 supplies a backlight turn-off instruction to the liquid crystal panel 10. Thereby, the liquid crystal panel 10 turns off the backlight.

  Next, the control unit 21 of the image quality adjustment apparatus 20 performs a determination process as to whether there is a reflection (step S3). Specifically, the management unit 211 of the control unit 21 instructs the external light monitoring unit 213 to check whether there is a reflection. In this case, the external light monitoring unit 213 uses the photographing camera 30 to acquire a surface image of the liquid crystal panel 10. Here, when a luminance measurement value equal to or higher than the reference value is detected by the reflected light in the surface image, the external light monitoring unit 213 determines that there is external light reflection. Then, the external light monitoring unit 213 supplies the management unit 211 with a determination result including the presence or absence of reflection.

  When it is determined that there is a reflection (in the case of “YES” in step S3), the control unit 21 of the image quality adjustment device 20 executes error processing (step S9). Specifically, the management unit 211 of the control unit 21 outputs a message indicating that the measurement is stopped on the display.

  On the other hand, when it is determined that there is no reflection (in the case of “NO” in step S3), the control unit 21 of the image quality adjustment apparatus 20 starts uneven adjustment (step S4). Specifically, the management unit 211 of the control unit 21 instructs the correction data generation unit 212 to start generation of correction data.

  And the control part 21 of the image quality adjustment apparatus 20 performs the determination process about whether adjustment was complete | finished (step S5). Specifically, the management unit 211 of the control unit 21 acquires the progress of measurement from the correction data generation unit 212.

  If the adjustment has not been completed (in the case of “NO” in step S5), the control unit 21 of the image quality adjustment apparatus 20 executes a measurement process (step S6). Specifically, the correction data generation unit 212 of the control unit 21 instructs the test pattern generation device 31 to output an RGB signal for outputting an image of the gradation to be adjusted. Here, in the gradation to be adjusted, signals having the same R signal value, G signal value, and B signal value (common signal values) are used for the entire surface of the liquid crystal panel 10. In response to this instruction, the test pattern generator 31 supplies the liquid crystal panel 10 with an 8-bit RGB signal that is the gradation to be adjusted.

  In response to this, the liquid crystal panel 10 outputs a gray image of the adjustment target gradation. In this case, when the liquid crystal has uneven cell gaps or uneven backlights, the liquid crystal panel 10 has display unevenness in which these unevennesses are superimposed. Here, the imaging camera 30 captures an image on which display unevenness is superimposed.

  Then, the correction data generation unit 212 takes in output image data obtained by photographing the liquid crystal panel 10 from the photographing camera 30. Then, the correction data generation unit 212 converts the output image data into a luminance distribution for each block composed of 8 × 8 pixels.

  Next, the correction data generation unit 212 executes a filtering process. Specifically, the correction data generation unit 212 calculates bandpass data by performing bandpass filtering on the acquired output image data. This band pass data is composed of a distribution excluding low frequency components and high frequency components according to the in-plane luminance distribution of the liquid crystal panel 10.

  Next, the control unit 21 of the image quality adjustment device 20 executes correction data generation processing (step S7). Specifically, the correction data generation unit 212 of the control unit 21 generates an image correction table in which bandpass data is inverted. Specifically, the distribution of correction values on the liquid crystal panel 10 is calculated for each preset gradation (reference gradation). In the present embodiment, a predetermined number (for example, 10 levels) of reference gradations are used in a signal value expressed in 8 bits. Then, the adjustment target gradation corresponding to the reference gradation is sequentially changed for each step, and an image correction table is generated for each adjustment target gradation. Further, the correction information generation means temporarily stores an image correction table in the correction information storage unit 22 in association with an identifier for specifying the adjusted reference gradation.

  Next, the control unit 21 of the image quality adjustment apparatus 20 executes a determination process for the presence or absence of brightness fluctuations (step S8). Specifically, the external light monitoring unit 213 of the control unit 21 uses the same image signal (adjustment) from the test pattern generator 31 to the liquid crystal panel 10 in the measurement process (step S6) and the correction data generation process (step S7). While the target gradation signal is being supplied, the photographing camera 30 performs photographing continuously or periodically to determine whether or not a luminance change has occurred on the screen of the liquid crystal panel 10. If a change in the brightness of the image has occurred, it is determined that there has been a change in brightness.

  When it is determined that there has been a change in brightness (in the case of “YES” in step S8), the control unit 21 of the image quality adjustment device 20 executes error processing (step S9). Specifically, the management unit 211 of the control unit 21 stops measuring the luminance unevenness of each pixel and outputs an alarm on the display.

When it is determined that there is no change in brightness (in the case of “NO” in step S8), the control unit 21 of the image quality adjustment device 20 continues the processing from step S5.
On the other hand, when the adjustment is completed (in the case of “YES” in step S5), the control unit 21 of the image quality adjustment apparatus 20 executes a correction data writing process (step S10). Specifically, the management unit 211 of the control unit 21 supplies the image correction table extracted from the correction information storage unit 22 to the ROM writer 32. In this case, the ROM writer 32 writes the image correction table in the ROM 51 of the liquid crystal panel 10. As a result, the distribution of correction values is recorded in the ROM 51 with respect to the block position (xy coordinates) in the plane of the liquid crystal panel 10 for each reference gradation.

According to this embodiment, the following effects can be obtained.
(1) In the present embodiment, the control unit 21 of the image quality adjustment device 20 performs a backlight OFF process (step S2). Next, the control unit 21 of the image quality adjustment apparatus 20 performs a determination process as to whether there is a reflection (step S3). When it is determined that there is a reflection (in the case of “YES” in step S3), the control unit 21 of the image quality adjustment device 20 executes error processing (step S9). If there is a reflection of external light on the screen of the liquid crystal panel 10, there is a possibility that correction data that is not accurate will be generated. Therefore, accurate correction data can be generated by determining the presence or absence of external light reflection before the start of measurement. And when there is a reflection of outside light, it is possible to alert the manager.

  (2) In the present embodiment, the control unit 21 of the image quality adjustment apparatus 20 determines whether or not there has been a change in brightness during the execution of the measurement process (step S6) and the correction data generation process (step S7) in the unevenness adjustment. The determination process is executed (step S8). As a result, when external light is reflected during the adjustment of the liquid crystal panel 10, the processing can be stopped and accurate correction data can be generated.

Moreover, you may change the said embodiment as follows.
In the above embodiment, the control unit 21 of the image quality adjustment apparatus 20 performs a determination process as to whether there is a reflection (step S3). Further, the control unit 21 of the image quality adjustment apparatus 20 executes a determination process as to whether or not there has been a change in brightness (step S8). In this case, the photographing camera 30 is used to detect external light reflections and brightness fluctuations. In addition to this, it is also possible to use an illuminance sensor (measuring means) that detects brightness separately from the photographing camera 30. Also in this case, when the illuminance sensor detects a change in brightness, error processing is executed. Thereby, the presence or absence of external light in the measurement area A can be constantly monitored.

  In the above embodiment, when it is determined that the brightness has changed (in the case of “YES” in step S8), the control unit 21 of the image quality adjustment apparatus 20 executes error processing (step S9). Specifically, the management unit 211 of the control unit 21 stops the measurement and outputs an alarm on the display. Here, when the reflection of external light is temporary, re-measurement may be performed. Specifically, the management unit 211 of the control unit 21 of the image quality adjustment apparatus 20 confirms whether or not external light is reflected. When there is no reflection, the management unit 211 resets the image data up to the step before the brightness change is detected (for example, the gradation range when the change is detected), and the test pattern generator 31 receives the reset. On the other hand, it instructs the signal output from the range of the image signal reset again. Then, the unevenness adjustment (measurement and generation of correction data) in this range is executed again. If the external light continues to be reflected, the unevenness adjustment is stopped. Thereby, when the reflection of external light is temporary, it can be measured again efficiently.

In the above embodiment, the control unit 21 of the image quality adjustment device 20 performs the backlight OFF process (step S2). When it is determined that there is no reflection (in the case of “NO” in step S3), the control unit 21 of the image quality adjustment device 20 starts uneven adjustment (step S4). Here, the backlight OFF process (step S2) and the presence / absence determination process (step S3) may be performed between the luminance measurements of each gradation.
Specifically, the management unit 211 of the control unit 21 performs a backlight OFF process when measuring the luminance of different gradations, and confirms whether or not external light is reflected. Thereby, the reflection of external light can be reliably detected and measurement can be performed.

  In the above embodiment, the control unit 21 of the image quality adjustment device 20 performs panel detection processing (step S1). Instead of this, the liquid crystal panel 10 may be mounted on a pallet and automatically conveyed to the measurement area A. In this case, the unevenness adjustment is started when it is confirmed by the backlight OFF process that the management unit 211 has no reflection.

  DESCRIPTION OF SYMBOLS 10 ... Liquid crystal panel, 20 ... Image quality adjusting device, 21 ... Control part, 22 ... Correction information storage part, 30 ... Shooting camera, 31 ... Test pattern generator, 32 ... ROM writer, 50 ... Correction circuit, 51 ... ROM.

Claims (5)

A panel evaluation system including a control unit that supplies an image signal to be displayed on the display panel and obtains a measurement value from a measurement unit that measures the luminance of each pixel displayed on the display panel,
The control means is
Means for supplying a backlight turn-off instruction to the display panel;
Means for obtaining a measurement value of luminance in the backlight off state from the measurement means;
If the measured value is greater than or equal to a reference value, an instruction to stop measuring the luminance unevenness of each pixel is output,
When it is less than the reference value, an image signal for measuring the luminance unevenness of each pixel is supplied to the display panel, and the display unit performs a display panel measurement process for measuring the luminance corresponding to the image signal by the measuring means. And a panel evaluation system.   Provide an instruction to turn off the backlight before starting the display panel measurement process, and output an instruction to stop measuring the luminance unevenness of each pixel when the measured luminance value is equal to or higher than the reference value when the backlight is turned off. The panel evaluation system according to claim 1.   In the measurement of the luminance unevenness of each pixel, when the same image signal is supplied to the display panel, if a change in luminance is detected, an instruction to stop measuring the luminance unevenness of each pixel is output. The panel evaluation system according to claim 1 or 2.   The measurement result in a predetermined range is reset when a luminance variation is detected in the same image signal, the image signal in this range is supplied again to the display panel, and remeasurement is performed. 3. The panel evaluation system according to 3. An image signal to be displayed on the display panel is supplied, and the display panel is evaluated by using a panel evaluation system including a control unit that acquires a measurement value from a measurement unit that measures the luminance of each pixel displayed on the display panel. A method,
The control means is
Supplying a backlight turn-off instruction to the display panel;
Obtaining a measurement value of luminance in the backlight off state from the measurement means;
If the measured value is greater than or equal to a reference value, an instruction to stop measuring the luminance unevenness of each pixel is output,
When it is less than the reference value, an image signal for measuring the luminance unevenness of each pixel is supplied to the display panel, and the display unit performs a display panel measurement process for measuring the luminance corresponding to the image signal by the measuring means. And a step of performing a panel evaluation method.

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