Luminance weighted discrete level display

• US 6,008,868 A
• Filed: 03/13/1995
• Issued: 12/28/1999
• Est. Priority Date: 03/11/1994
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Silverbrook, Kia
• Primary Examiner(s): LEE, MICHAEL
• Application Number:
  US08/402,505
• Time in Patent Office: 1,751 Days
• Field of Search: 345/32, 345/84, 345/90, 345/103, 345/149, 345/151, 345/152, 345/88, 345/150, 348/790, 348/791, 348/803, 359/54, 359/61, 359/68, 359/87, 349/3, 349/108, 349/145, 349/146
• US Class Current: 348/790
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2340/0457 Improvement of perceived resolution by subpixel rendering
• CPC Class Codes: G09G 2370/045 using multiple communication channels, e.g. parallel and serial
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 3/364 with use of subpixels
• CPC Class Codes: G09G 3/3681 suitable for passive matrices only
• CPC Class Codes: G09G 3/3692 suitable for passive matrices only
• CPC Class Codes: G09G 5/42 characterised by the display of patterns using a display memory without fixed position correspondence between the display memory contents and the display position on the screen

Abstract

The construction of display devices often involves the replication of a single pixel design a large number of times. Full color display devices are often constructed on the principle of utilising multiple primary colors in order to form a final destination color. Previously, the degree of complexity of the pixel arrangement devoted to each primary color was substantially the same. The present invention discloses devoting a variable degree of complexity to each primary color in a pixel layout depending on the perceptual response of the human eye to the particular primary color. For example, there is disclosed a pixel arrangement having red, green and blue primary colors wherein substantial complexity is devoted to the green primary color with a lesser complexity devoted to the blue primary color.

Claims

1. A method for determining a number of drive lines allocated to each primary color of a discrete level color display, the display having a plurality of pixels, each formed from a plurality of independently illuminable areas, and each of which is assigned to a red (R), green (G) or blue (B) primary color component, said method comprising at least the step of allocating the drive lines to the primary color components such that, for each pixel a number of discrete intensity levels for the G component exceeds a number of discrete intensity levels for the R component, and the number of discrete intensity levels for the R component exceeds a number of discrete intensity levels for the B component.

3. A method as claimed in claim 1, wherein the number of illuminable areas corresponding to each color component is distinct from the number of illuminable areas of at least one of the other color components.

6. A method as claimed in claim 3, wherein the number of the illuminable areas for each of the primary color components is different.

2. A color display apparatus having a first plurality of independently illuminable areas connected to a second plurality of data drive lines, each of said illuminable areas being assigned to a red (R), green (G) or blue (B) primary color component, wherein, for each pixel, said data drive lines are allocated to said primary color components such that a number of discrete intensity levels for the G component of the color display apparatus exceeds a number of discrete intensity levels for the R component, and the number of discrete intensity levels for the R component exceeds a number of discrete intensity levels for the B component.

4. A color display as claimed in claim 2, wherein the number of illuminable areas of each color component is different from the number of illuminable areas of at least one of the other color components.

12. A color display apparatus as claimed in claim 4, wherein the number of said illuminable areas for each of said primary color components is different.

5. A method for determining a number of drive lines allocated to each primary color of a discrete level color display, the display having a plurality of pixels, each pixel having a plurality of independently illuminable areas, each area being assigned to one of a plurality of primary color components selected from among red (R), green (G) and blue (B), each of the primary color components having a corresponding average human eye response function, said method comprising, for each of the pixels, at least the step of allocating the drive lines to the primary colors substantially in a logarithmic manner related to the corresponding average human eye response functions.

7. A method as claimed in claim 5, wherein the display is a discrete level ferro-electric liquid crystal display.

8. A method as claimed in claim 5, wherein the illuminable areas of each primary color component are substantially binary weighted.

9. A method as claimed in claim 5, wherein the number of independently illuminable red areas is two, the number of independently illuminable green areas is three and the number of independently illuminable blue areas is one.

10. A method as claimed in claim 5, wherein the number of red drive lines is two, the number of green drive lines is three and the number of blue drive lines is one.

11. A color display apparatus having a first plurality of independently illuminable areas connected to a second plurality of data drive lines, each of the independently illuminable areas being assigned to a red (R), green (G) or blue (B) primary color component, wherein each of said primary color components has a corresponding average human eye response function, and said data drive lines are allocated to said primary color components substantially in a logarithmic manner related to the corresponding average human eye response function.

13. A color display apparatus as claimed in claim 11, wherein the number of red drive lines is two, the number of green drive lines is three and the number of blue drive lines is one.

15. A color display apparatus according to claim 11, wherein the number of read drive line is two, the number of green drive lines is three and the number of blue drive lines is one.

14. A method for determining the number of drive lines allocated to each primary color of a discrete level color display, the display having a plurality of pixels, each pixel having a plurality of independently illuminable areas, each area being assigned to one of a plurality of primary color components included in the group of red, green and blue, said method comprising at least the step of allocating the drive lines to the primary color components in a ratio such that a condition of the illuminable areas to one color component is different from that of the illuminable areas to the other color component, wherein each primary color component has a corresponding average human eye response function, and said allocating step further comprises allocating the drive lines to the primary colors in a ratio substantially in accordance with a logarithmic ratio of the corresponding average human eye response functions, wherein the primary color components are red, green and blue and the number of red drive lines is two, the number of green drive lines is three and the number of blue drive lines is one.