Mixed monochrome and colour display driving technique

• US 7,714,832 B2
• Filed: 06/02/2004
• Issued: 05/11/2010
• Est. Priority Date: 06/02/2004
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Tong, Kuo-Feng, Lowles, Robert, Drader, Marc
• Primary Examiner(s): Tran; Henry N
• Application Number:
  US10/858,070
• Publication Number:
  US 20060007098A1
• Time in Patent Office: 2,169 Days
• Field of Search: 345/204, 345/209, 345212-214, 345/690, 345/692, 345 87- 90, 345/92, 345 94- 96, 345 98-100, 345/102, 345/103
• US Class Current: 345/103
• CPC Class Codes: G02F 1/133391 Constructional arrangement for sub-divided displays
• CPC Class Codes: G09G 2310/0205 Simultaneous scanning of several lines in flat panels
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A display screen is capable of having regions having different switching speeds as well as regions that are not switched. One region having a first switching speed may be for colour mode display and the other region having a second switching speed different from the first may be for monochrome mode display. Other regions may be off and not switched. In alternative versions, three or more switched regions may be established on a display screen. For example, a monochrome region may be nested inside a colour region, in which the colour region may be nested between off regions.

Claims

1. A method for generating a frame of an image on an LCD screen of a handheld wireless communications device having a plurality of light-sources, comprising:

scanning a first region of contiguous lines of field sequentially driven liquid crystal pixels to produce a colour region on the LCD screen, using a source driver and a gate driver driven at a first frequency; and

scanning a second region of contiguous lines of field sequentially driven liquid crystal pixels to produce a monochrome region on the LCD screen, using said source driver and said gate driver driven at a second frequency less than said first frequency, wherein said colour region is produced by scanning, in said frame, said first region a first number of times; and

wherein said monochrome region is produced by scanning said second region a second number of times such that said first number of times is N times said second number of times, such that switching losses in said colour region is less than switching losses in said monochrome region; and

activating said light sources during a portion of said frame.

2. The method of claim 1, wherein N is a positive integer and obeys a selected one of the following relationships:

i) N is greater than three;

ii) N is between six and sixteen, inclusive;

iii) N is between six and twelve inclusive;

iv) N is equal to six;

v) N is equal to eight; and

vi) N is equal to ten.

3. The method of claim 1, further comprising scanning a third region of contiguous lines of field sequentially driven liquid crystal pixels to produce a second colour region on the LCD screen.

4. The method of claim 3, wherein said second colour region is performed by scanning in said frame, said third region by a third number of times.

5. The method of claim 4, wherein said third number of times is the same as said first number of times.

6. The method of claim 4, wherein said third number of times is different from said first number of times.

7. The method of claim 3, wherein said second colour region is different from said first colour region.

8. The method of claim 7, wherein at least one of said first colour region, said second colour region and said monochrome region comprises a bit rate colour scheme different from a bit rate colour scheme of at least one other region.

9. The method of claim 1, further comprising leaving at least one line of pixels in an off state.

10. The method of claim 1, wherein said frame comprises a first portion respective to said first region and a second portion respective to said second region;

and wherein pixels in each of said portions are refreshed at different frame rates.

11. The method of claim 1, wherein said monochrome region is comprised of black and white.

12. The method of claim 1, further comprising the steps of:

receiving a source pattern for said frame for presenting on the LCD screen, said pattern including at least said first region and said second region;

receiving a number of lines respective to each region, each of said lines including a plurality of pixels;

receiving a pulse sequence per region corresponding to a desired pattern for that region wherein one of said pulse sequences consumes less power than at least one other of said pulse sequences;

receiving a light sequence corresponding to each said region;

scanning each liquid crystal pixel in each line respective to each region according to said pulse sequence respective to that region; and

activating said light sources according to said light sequence respective to each said region.

13. The method of claim 12, wherein said light sources are comprised of three separate colours red, green and blue or cyan, magenta, and yellow.

14. The method of claim 13, said light sequence is comprised of three sequential parts respective to each said colour.

15. The method of claim 14, wherein each said colour is turned on during all of its respective said part.

16. The method of claim 14, wherein each said colour is turned on during a portion of its said respective part.

17. The method of claim 12, wherein said scanning step comprises scanning one of said regions before scanning another of said regions.

18. The method of claim 12, wherein said pattern includes a third region of contiguous lines of field sequentially driven liquid crystal pixels to produce a second colour region on the LCD screen, wherein said scanning step comprises simultaneously scanning said first region and said third region.

19. The method of claim 1, wherein scanning the first region of contiguous pixel lines occurs three times in a frame.

20. The method of claim 19, wherein each of the three times corresponds to a different colour of illumination light.

21. A wireless communications device comprising:

an LCD screen having multiple lines of liquid crystal pixels arranged in a matrix;

said LCD operable to generate a frame of an image having at least one colour region and at least one monochrome region;

a source driver and a gate driver for scanning said pixels according to a pulse sequence per region corresponding to a desired pattern for that region, said source driver and said gate driver driven at a first frequency to produce said colour region, and said source driver and said gate driver driven at a second frequency less than said first frequency to produce said monochrome region, wherein said colour region is produced by scanning, in said frame, said first region a first number of times; and

wherein said monochrome region is produced by scanning said second region a second number of times such that said first number of times is N times said second number of times, such that switching losses in said colour region is less than switching losses in said monochrome region; and

a plurality of light sources operable according to a light sequence corresponding to each said region.

22. The wireless communications device of claim 21, wherein said light sources include light emitting diodes.

23. The wireless communications device of claim 22, wherein a first one of said light emitting diodes emits red light, a second one of said light emitting diodes emits green light, and a third one of said light emitting diodes emits blue light or a first one emits cyan light, a second one emits magenta light, and a third one emits yellow light.

24. The wireless communications device of claim 21, wherein said source driver is loaded with values to drive source lines of a sequentially selected row of said pixels by shifting a bit through a shift register to drive gates in said matrix;

and wherein said sequential selection of rows is accomplished by selectively loading one shift register selected from a plurality of shift registers.

25. The wireless communications device of claim 21, further comprising a display controller for controlling the display screen and a light source controller for controlling the light source.

26. The wireless communications device of claim 25, wherein the display controller controls operations of the light source controller.

27. The wireless communications device of claim 21, wherein each pixel in the one of said regions is capable of being scanned on between two and sixteen times, inclusive, for each time any pixel another of said regions is scanned.

28. The wireless communications device of claim 21, wherein the source driver is loaded with values to drive source lines of a selected row of the pixels.

29. The wireless communications device of claim 28, wherein the values are read from a look up table.

30. The wireless communications device of claim 28, wherein each of the values for the first region is multiple bits in length and each of the values for the second region is a single bit in length.

31. The wireless communications device of claim 28, wherein the gate driver is capable of selecting rows of pixels for monochrome mode and selecting other rows of pixels for colour mode.

32. The wireless communications device of claim 31, wherein selection of rows within a region is performed in a sequential manner.

33. The wireless communications device of claim 31, wherein the selection of rows in a sequential manner is accomplished by at least one of selectively loading one shift register selected from a plurality of shift registers and selectively loading one shift register selected from a plurality of shift registers.