Display device adjusting method and display device

• US 20060152468A1
• Filed: 03/26/2004
• Published: 07/13/2006
• Est. Priority Date: 04/01/2003
• Status: Abandoned Application

• Current Assignee: Hunet Display Technology, Inc.
• Original Assignee: Hunet Display Technology, Inc.
• Inventors: Ozaki, Yutaka
• Application Number:
  US10/532,240
• Publication Number:
  US 20060152468A1
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

An LED of each of colors, red, green and blue, undergoes PWM control independently in a unit emission period to emit light, luminance/chromaticity meter 31 measures the chromaticity of the light, a difference is calculated between the measured value and target white balance value, a duty ratio is corrected on the LED of each color corresponding to the difference to light the LED of each color again, and the duty ratio for the LED of each color such that the difference falls within a predetermined allowable range is stored in duty ratio storage register 21, 22 or 23.

Claims

1. An adjustment method of a display device, comprising:

an LED emission step of performing PWM control independently on an LED of each of colors, red, green and blue, in a unit emission period to cause the LED to emit light;

a measuring step of measuring chromaticity of the light;

a calculating step of calculating a difference between a measured value obtained in the measuring step and a target white balance value;

a correcting step of correcting a duty ratio of a PWM signal on the LED of each of colors in the LED emission step corresponding to the difference obtained in the calculating step; and

a duty ratio storing step of storing a duty ratio for the LED of each of colors in a storage when the difference calculated in the calculating step falls within a predetermined allowable range.

2. The adjustment method of a display device according to claim 1, wherein an adjustment of the display device is made in such a state that an LCD panel is attached to a front face of the LED and that the LCD panel is driven.

3. The adjustment method of a display device according to claim 1, wherein in the correcting step, the duty ratio of the PWM signal for the LED of each of colors is corrected in consideration of a distribution range of the chromaticity of the LED of each of colors.

4. The adjustment method of a display device according to claim 1, wherein the duty ratio is corrected independently on LEDs of the same color corresponding to the difference obtained in the calculating step, and independent duty ratios for the LEDs of the same color are stored in the duty ratio storing step.

5. A display device comprising:

a duty ratio storage which is comprised of writable memory and stores therein a duty ratio to perform PWM control independently on an LED of each of colors, red, green and blue, in a unit emission period, independently for each LED;

a PWM controller which forms a PWM signal based on the duty ratio stored in the duty ratio storage independently for each LED to perform PWM control independently on the LED of each of colors in the unit emission period; and

a signal line connected to the duty ratio storage to input the duty ratio to the duty ratio storage.

6. The display device according to claim 5, wherein the duty ratio storage stores the duty ratio provided with a white balance adjustment via the signal line.

7. The display device according to claim 5, wherein the duty ratio storage stores independent duty ratios for LEDs of the same color, and the PWM controller forms independent PWM signals for the LEDs of the same color to perform PWM control independently on the LEDs of the same color in a unit emission control.