Electro optical device, electric apparatus and pixel rendering method

• US 10,032,403 B2
• Filed: 02/19/2016
• Issued: 07/24/2018
• Est. Priority Date: 02/20/2015
• Status: Active Grant

• Current Assignee: Tianma Microelectronics Company Limited
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Matsueda, Yojiro, Hamada, Keita
• Primary Examiner(s): Watko, Julie Anne
• Application Number:
  US15/047,771
• Publication Number:
  US 20160247441A1
• Time in Patent Office: 886 Days
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2340/0457 Improvement of perceived resolution by subpixel rendering
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/2059 using error diffusion
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

An electro optical device has a pixel array constituted by pixels arranged in matrix, each pixel including four subpixels, the four subpixels including RGB subpixels and a subpixel of a similar color to a specific color among RGB, and the four subpixels being arranged in two rows and two columns. In each pixel, a first subpixel having the highest emission luminance and a second subpixel having the second highest emission luminance among subpixels needed for white display are arranged on one diagonal line of the pixel, and the other subpixels are arranged on the other diagonal line. The electro optical device has a control unit that executes switching between a first driving condition and a second driving condition in accordance with a color of a pixel to be displayed, the first driving condition in which both the subpixel of the specific color and the subpixel of the similar color are driven to emit light with the first luminance ratio, and the second driving condition in which both the subpixels of the specific color and the similar color are driven to emit light with the second luminance ratio.

Claims

1. A pixel rendering method in an electro optical device comprising a pixel array constituted by pixels arranged in matrix, each pixel including four subpixels, the four subpixels including subpixels of colors of R (Red), G (Green) and B (Blue), and a subpixel of a similar color to a specific color, the specific color being a color of subpixel including a light emitting material having a shortest lifetime among the light emitting materials included in the subpixels of colors of R, G and B, respectively, and the four subpixels being arranged in two rows and two columns, and

each of the pixels including:

a first subpixel having a highest emission luminance and a second subpixel having a second highest emission luminance among subpixels needed to display a white color, both the first subpixel and the second subpixel being arranged on one diagonal line of the pixel; and

a third subpixel having a third highest emission luminance and a fourth subpixel having a lowest emission luminance, both the third subpixel and the fourth subpixel being arranged on another diagonal line of the pixel, wherein

the method comprises;

extracting a corner, a straight line, a boundary, or a dot which is to be displayed in the pixel array; and

making a subpixel emit light with a predetermined value of luminance, the subpixel being in an adjacent pixel located adjacent to the first subpixel or the fourth subpixel within each pixel arranged at the corner, the straight line, the boundary, or the dot, and the adjacent pixel being not located at the corner, the straight line, the boundary, or the dot.

2. The pixel rendering method according to claim 1, comprising

in a case where the image is a white dot,

making at least one of the first subpixel and the second subpixel in the adjacent pixel emit light, the at least one of the first subpixel and the second subpixel in the adjacent pixel being adjacent to the fourth subpixel in a pixel of the white dot.

3. The pixel rendering method according to claim 2, wherein

the adjacent pixel comprises the pixel being adjacent in the fourth subpixel of the pixel of the white dot in a row direction, and the pixel being adjacent to the fourth subpixel of the pixel of the white dot in a column direction, and

the method comprises making the first subpixel and the second subpixel adjacent to the fourth subpixel of the pixel of the white dot among the subpixels of the adjacent pixel emit light with different values of luminance from each other.

4. The pixel rendering method according to claim 1, comprising

in a case where the image is a white dot,

making at least one of the fourth subpixel and the third subpixel in the adjacent pixel emit light, the at least one of the fourth subpixel and the third subpixel in the adjacent pixel being adjacent to the first subpixel in a pixel of the white dot.

5. The pixel rendering method according to claim 4, wherein

the adjacent pixel comprises the pixel being adjacent to the first subpixel of the pixel of the white dot in a row direction, and the pixel being adjacent to the first subpixel of the pixel of the white dot in a column direction, and

the method comprises making the fourth subpixel and the third subpixel adjacent to the first subpixel of the pixel of the white dot among the subpixels of the adjacent pixel emit light with different values of luminance from each other.

6. The pixel rendering method according to claim 1, comprising

in a case where the image is a white line having a width of one pixel,

making the first subpixel or the second subpixel in the adjacent pixel outside the white line emit light, the first or second subpixel in the adjacent pixel being adjacent to the fourth subpixel in each pixel inside the white line, and making the second subpixel or the first subpixel in the adjacent pixel outside the white line emit light, the second or first subpixel in the adjacent pixel being adjacent to the third subpixel in the each pixel inside the white line.

7. The pixel rendering method according to claim 1, comprising

in a case where the image is a white line having a width of one pixel,

making the fourth subpixel or the third subpixel in the adjacent pixel outside the white line emit light, the fourth or third subpixel in the adjacent pixel being adjacent to the first subpixel in each pixel inside the white line, and making the third subpixel or the fourth subpixel in the adjacent pixel outside the white line emit light, the third or fourth subpixel in the adjacent pixel being adjacent to the second subpixel in the each pixel inside the white line.

8. The pixel rendering method according to claim 1, wherein the specific color is deep blue (B2) and the similar color is light blue (B1).

9. The pixel rendering method according to claim 1, comprising

in a case where the image is a white line having a width of two or more pixels,

making the first subpixel or the second subpixel in the adjacent pixel outside the white line emit light, the first or second subpixel in the adjacent pixel being adjacent to the fourth subpixel in each pixel located at an edge of the white line, and making the second subpixel or the first subpixel in the adjacent pixel outside the white line emit light, the second or first subpixel in the adjacent pixel being adjacent to the third subpixel in the each pixel located at the edge of the white line.

10. The pixel rendering method according to claim 1, comprising

in a case where the image is a white line having a width of two or more pixels,

making the fourth subpixel or the third subpixel in the adjacent pixel outside the white line emit light, the fourth or third subpixel in the adjacent pixel being adjacent to the first subpixel in each pixel located at an edge of the white line, and making the third subpixel or the fourth subpixel in the adjacent pixel outside the white line emit light, the third or fourth subpixel in the adjacent pixel being adjacent to the second subpixel in the each pixel located at the edge of the white line.