TWM492582U - Self-image calibration device of liquid crystal display - Google Patents

Description

Self-image correction device for liquid crystal display

This creation belongs to the field of display image correction technology, especially to a self-image correction device for a liquid crystal display, thereby saving human resources and shortening the overall maintenance and manufacturing engineering.

According to the general display image correction technology, it can be divided into two types: hardware correction and software correction. The hardware correction is a storage device that stores the adjusted data in the display, and the software is corrected to use the color profile (ICC Profile). Through the computer's operating system to achieve image correction purposes.

Traditional display calibration, whether it is hardware or software calibration, requires the use of external devices such as computers, colorimeters, etc., as well as the professional software required to calibrate the display. It is not convenient to set up the above-mentioned external devices in some cases. Such as buried wall displays, displays in the operating room, and so on. Especially in the medical system equipment where frequent use and imaging are required to maintain high standards, external devices and professional software are also a small overhead for maintenance costs.

However, because each display panel has slight differences in its production, the physical characteristics are slightly different, and the maximum brightness is also inconsistent. Even after gamma correction and color temperature compensation, the brightness difference is more pronounced. Especially for medical systems with high frequency and precise display of hue, A high standard reference value needs to be maintained in order to provide the doctor with the correct judgment.

In the prior art, Taiwan Patent Publication No. 200627369, only one method of adjusting the image color temperature is provided, which is to record an image or the like by transmitting the physical characteristics of the electronic circuit.

[Patent Document 1] Taiwan Patent Publication No. 200627369

In order to effectively solve the above problems, the author uses the front light sensor and the sensing component provided on the display, as long as the front light sensor is calibrated at the factory, the external device and the software setting can be achieved. Display independent self-image correction function. It can be used in situations where it is not convenient to install an external device and reduce the cost of correcting maintenance of the display.

The main purpose of the present invention is to provide a self-image correcting device for a liquid crystal display, the correcting device comprising a front light sensor, a correction reference device, the front light sensor being disposed in front of the liquid crystal display panel, the correction reference The device is disposed at an intermediate position of the liquid crystal display, the correction reference device is connected to the display to a computer, and the front light sensor is configured to correct gray scale and color temperature of the display, the correction reference device is used for Pre-correct the front light sensor.

The present invention discloses the beneficial effects: the pre-image correction of the installed front light sensor is performed at the factory, and the corrected front light sensor is directly used to adjust the gray scale and color temperature of the display screen, and the installation is simple and effective. Detecting the corrected display image.

1‧‧‧ display

2‧‧‧ Front light sensor

3‧‧‧Correction reference device

4‧‧‧Test screen

FIG. 1 is a schematic diagram of correcting the front light sensor according to the creation; Figure 2 is a schematic diagram of the self-correction of the front light sensor.

The above object of the present invention and its structural and functional characteristics will be further explained based on the following drawings and specific implementation methods, please refer to FIG. 1 and FIG.

This creation includes the following three steps:

The first step: erecting the front light sensor of the display

By arranging the front light sensor 2 in front of the panel of the liquid crystal display 1, it is possible to avoid factors such as brightness degradation caused by the deterioration of the liquid crystal display panel, and to obtain more accurate measurement data.

The second step: verifying the front light sensor, and implementing the following method to obtain the measured data, and comparing with the calibration reference device to obtain a difference. If the difference is smaller than the error range Delta E (2000) < 5, the calibration is successful.

1. Set up a colorimeter or spectrometer at the appropriate position of the display as the calibration reference device 3; 2. Connect the display 1 and the calibration reference device 3 to the computer; 3. Adjust the brightness of the display 1 to the lowest value of the use range, and display all black Test screen. After waiting for the brightness to stabilize, the front light sensor 2 measures the measured values of the three channels of Red, Green, and Blue. At the same time, the chromaticity space coordinates x, y and brightness (lightness) Y measured by the reference device 3 are corrected. .

4. Display 1 displays test screen 4, and calibration reference device 3 measures data such as chromaticity space coordinates x , y and brightness (lightness) Y , and stores the measured data, while front light sensor measures Red, Green, Blue value and Clear Channel data, and store the data obtained by the measurement; the application test screen is rgb=(255 0 0), rgb=(0 255 0), rgb=(0 0 255) Test screen, the data measured by the calibration reference device is three sets of data The corresponding front light sensor measures the data .

5. The relationship equation between the chromaticity space and the color stimuli value is applied, where x and y in the formula are chromaticity space coordinates, and X , Y , and Z are color stimuli values: Converting the data measured by the calibration reference device in steps 3 and 4 into color stimulus values, and obtaining four sets of color stimulation values. 6. Establish a transformation matrix between the data measured by the front light sensor and the color stimulus value of step four and find the transformation matrix coefficient to create a conversion equation: (2) among them For color stimuli, Information measured for the front light sensor.

The data measured by the front light sensor in the above steps 3, 4, and 5 and the color stimulus value measured and converted by the calibration reference device are brought into the conversion equation to obtain the conversion matrix M. ,

7. The display shows other test screens. The front light sensor measures, obtains the measurement data and brings the measurement data into equation (2) and converts X, Y, Z into x , y , Y values, which will be x , y , Y is compared with the calibration reference device to obtain a difference. If the difference is smaller than the error range, the calibration is successful.

Third step: front light sensor self-correcting display

First, use the front light sensor to measure the darkest brightness value L _min and the brightest brightness value L _max of the display, and calculate the contrast value of the display C = L _max / L _min to confirm that the contrast value of the display complies with the DICOM specification.

Second, adjust the gamma value in the following way

a. Feedback control by the front light sensor to adjust the backlight of the display to the appropriate brightness, the brightness must be greater than the minimum brightness specified in DICOM; b. The display produces a 32-step grayscale test picture, measured and recorded by the front light sensor The luminance characteristic curve of the display is established by using the brightness as a reference; c. the reference brightness is interpolated by cubic spline interpolation according to the requirements of the display wafer, and the brightness reference table required for the display wafer is obtained. (luminance reference table), the size of the brightness reference table is n ; d. The target gamma value is obtained according to the gamma value formula (5), and the required brightness level is obtained in the brightness reference table. Number, fill it into the gamma table (GAMMA table).

Equation (5), L ( x )= L ₀ +( L _{n -1} - L ₀ )×( x / n ) ^γ x =0,1... n -1

e. The display firmware loads the gamma table adjusted in step d, and re-measures the gray scale curve to verify that the calibration result is correct and completes the gamma correction.

Third, adjust the color temperature in the following ways

a. Use the front light sensor to perform feedback control to adjust the backlight of the display to the appropriate brightness, the brightness must be greater than the minimum brightness specified in DICOM; b. The display shows the all-white test picture, and the front light sensor uses the conversion matrix to measure The display's current chrominance space coordinates x , y and luminance (lightness) Y values, the display R, G, B-Gain (red gain, green gain, and blue gain) values in the scratchpad, where R-Gain and The color coordinate (x, y) corresponding to the color temperature is proportional to x, G-Gain is proportional to y, and B-Gain is inversely proportional to x and y. In addition, R Gain, G Gain and B Gain and the brightness Y of the display screen satisfy the following formula: Y = 0.299 * R Gain + 0.587 * G Gain + 0.114 * B Gain, thus adjusting the display R, G in the register , B-Gain to adjust the color temperature of the display screen; c. Load the adjusted R, G, B-Gain values from the firmware and measure again to confirm whether the display chromaticity space coordinates x , y and brightness (lightness) Y value fall Into the error tolerance range, the color temperature adjustment is completed.

This creation performs pre-image correction on the installed front light sensor, and directly adjusts the gray scale and color temperature of the display screen by using the front light sensor, which is simple to install and can effectively detect and correct the display image.

The above examples are used to illustrate the creation, not to limit it. Within the scope of the claims of the present invention, any modifications to the present invention fall within the scope of this creation.

1‧‧‧ display

2‧‧‧ Front light sensor

3‧‧‧Correction reference device

4‧‧‧Test screen

Claims (10)

A self-image correcting device for a liquid crystal display, wherein a front light sensor is disposed in front of a liquid crystal display panel, the correcting device is in an intermediate position of the liquid crystal display, and the correcting device and the display are connected to a computer, A front light sensor is used to correct the gray scale and color temperature of the display, and the correcting device is configured to pre-correct the front light sensor, and the front light sensor needs to be pre-corrected before application. The device of claim 1, wherein the device comprises: (1) erecting a front light sensor of the display; (2) verifying the front light sensor using the calibration reference device; (3) The front light sensor corrects the gamma and color temperature of the display. The device of claim 2, wherein the (2) further comprises: (21) erecting a calibration reference device in front of the display; (22) connecting the display and the calibration reference device to the computer; 23) The display shows the test screen, the calibration reference device measures the chromaticity space coordinates x, y and the brightness value Y and stores it by the computer, the front light sensor measures the display and stores the measurement data; (24) the above step (23) The data measured by the medium correction reference device is substituted into the relationship equation between the chromaticity space and the color stimuli value to obtain the color stimuli value; (25) the data obtained by the front light sensor and the color obtained in the step (24) in the step (23) are established. a transformation matrix between the stimulus values and finding the transformation matrix coefficients; (26) The display displays other test pictures, which are measured by the front light sensor, and the measured data is converted into chromaticity space coordinates and brightness values, and compared with the space coordinates and brightness values obtained by the calibration reference device, the error is smaller than the error range. Delta E (2000) < 5, verification is complete. The device of claim 2, wherein the correction reference device is a colorimeter or a spectrometer. The device of claim 2, wherein the correction of the gamma value by the front light sensor comprises: (311) the front light sensor performs feedback control to adjust the backlight of the display, so that the brightness is greater than DICOM. The lowest brightness specified in the specification; (312) the display displays the test picture, the front light sensor measures and records as the reference brightness, and establishes the brightness characteristic curve of the display according to the reference brightness; (313) according to the requirements of the display chip, the reference The brightness is interpolated to obtain the brightness reference table required by the display wafer, and the brightness reference table size is n ; (314) the target gamma value is based on the gamma value formula L ( x ) = L ₀ + ( L _{n -1} - L ₀ ) × ( x / n ) ^γ x =0,1... n -1 Find the required brightness value for each step, and take the closest corresponding order in the brightness reference table, and fill it into the gamma table (315) The display firmware loads the gamma table adjusted in step (314), and re-measures the gray scale curve to verify that the tuning result is correct, and completes the gamma correction. The application apparatus according to item 5 of patentable scope, characterized in that, prior to the (311) further comprises: using the light sensor in front of the display measured value L _min darkest and the brightest luminance value L _max, calculated The contrast value of the display is C = L _max / L _min to confirm that the contrast value of the display complies with the DICOM specification. The apparatus of claim 5, wherein the reference curve is interpolated by applying a cubic curve interpolation method in (313). The device of claim 2, wherein the correction of the color temperature by the front light sensor comprises: (321) the front light sensor performs feedback control to adjust the backlight of the display, so that the brightness is greater than the specification in DICOM. The lowest brightness; (322) the display shows the test picture, the front light sensor measures the data and obtains the current chromaticity space coordinates and brightness values of the display through the conversion matrix, according to the R, G, B-Gain values and the chromaticity space coordinates. Relationship, adjust the display R, G, B-Gain in the register to adjust the color temperature of the display screen; (323) load the adjusted R, G, B-Gain values from the firmware and measure again to confirm the display chromaticity space Whether the coordinates and the brightness value fall within the error tolerance range Delta E (2000) < 5, the color temperature adjustment is completed. A self-image correcting device for a liquid crystal display, the correcting device comprising a front light sensor, a correction reference device, the front light sensor being disposed in front of the liquid crystal display panel, the correction reference device being disposed in an appropriate middle of the liquid crystal display Positioning, the correction reference device and the display are connected to a computer, wherein the front light sensor is configured to correct gray scale and color temperature of the display, and the correction reference device is used for front light The sensor is pre-corrected. The calibration device of claim 9, wherein the correction reference device is a colorimeter or a spectrometer.