Data dependent drive scheme and display

• US 20090303207A1
• Filed: 06/06/2008
• Published: 12/10/2009
• Est. Priority Date: 06/06/2008
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Ng, Sunny Yat-san
• Granted Patent: US 8,228,350 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/063 Waveforms for resetting the whole screen at once
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/2033 with splitting one or more sub-frames corresponding to the most significant bits into two or more sub-frames
• CPC Class Codes: G09G 3/2037 with specific control of sub-frames corresponding to the least significant bits
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 5/399 using two or more bit-mapped memories, the operations of which are switched in time, e.g. ping-pong buffers

Abstract

A method for writing data to a display includes the steps of receiving a plurality of data bits, where each bit is associated with a different pixel of the display, reading the value of each data bit, determining whether each data bits has an off-state value, and generating a disable signal if each data bit has an off-state value. Responsive to a disable signal, the method further includes suspending the transfer of data to the pixels of the display, turning off a light source (e.g., an LED, laser, etc.) for a time period dependent on the significance of at least one of the data bits, and/or forcing each pixel of the display into an off state for a time period dependent on the significance of at least one of the data bits. A display driver circuit for performing the methods of the present invention is also disclosed.

Claims

1. In a display system, a method for controlling a light source, said method comprising:

receiving a plurality of data bits, each of said data bits associated with a different pixel of a display;

reading the value of each of said data bits;

determining whether each of said data bits has a value indicative of an off-state; and

generating a disable signal if each of said data bits has a value indicative of said off-state, said disable signal causing said light source to turn off.

2. A method according to claim 1, wherein said step of receiving a plurality of data bits further includes:

receiving a plurality of multi-bit data words, each of said multi-bit data words associated with a different pixel of said display; and

planarizing the bits of said plurality of multi-bit data words according to bit plane, each of said bit planes containing bits of equal significance.

3. A method according to claim 2, further comprising turning off said light source responsive to said disable signal for a time period dependent on the significance of at least one of said bit planes.

4. A method according to claim 3, wherein:

each of said data bits in a first bit plane have said value indicative of said off-state; and

said light source is turned off for a time period equal to the significance of each bit in said first bit plane.

5. A method according to claim 3, wherein:

each of said data bits in a first bit plane have said value indicative of said off-state;

said light source is turned off for a time period equal to the significance of each bit in said first bit plane;

said light source is turned off for a time period equal to the significance of each bit in a second bit plane;

said data bits in said first bit plane are sequential bits; and

each of said sequential bits indicates that the value of at least one data bit in said second bit plane is indicative of said off-state.

6. A method according to claim 2, further comprising:

determining whether each of the data bits in each of said bit planes has a value indicative of said off-state; and

generating a separate disable signal for particular ones of said bit planes where each of said data bits in said particular bit plane has a value indicative of said off-state.

7. A method according to claim 6, wherein:

said step of generating said disable signal for particular ones of said bit planes further includes setting a plurality of indicators;

each of said indicators is associated with a different one of said bit planes; and

each of said indicators indicates whether each of said data bits in said associated bit plane has said value indicative of said off state.

8. A method according to claim 1, further comprising turning said light source on in the absence of said disable signal.

9. A method according to claim 1, further comprising:

receiving a second plurality of data bits, each of said second plurality of data bits associated with a different pixel of said display;

reading the value of each of said second plurality of data bits;

determining whether each of said second plurality of data bits has a value indicative of an off-state; and

generating a disable signal if each of said second plurality of data bits has said value indicative of said off-state.

10. A method according to claim 1, further comprising:

receiving a second plurality of data bits, each of said second plurality of data bits associated with a different pixel of said display;

keeping said light source turned off for an additional time period dependent on the significance of at least one of said second plurality of bits; and

wherein

said plurality of data bits are sequential bits; and

said sequential bits indicate that the value of each of said second plurality of data bits is indicative of said off-state.

11. A method according to claim 1, wherein:

said step of receiving said plurality of data bits includes receiving a plurality of sequential bits, each of said sequential bits associated with one of said pixels of said display; and

each of said sequential bits indicates the value of at least one other bit associated with said pixel.

12. A method according to claim 1, wherein said light source includes a light-emitting diode (LED).

13. A method according to claim 1, wherein said light source includes a laser.

14. An electronically-readable medium having code embodied therein for causing an electronic device to perform the method of claim 1.

15. A display driver circuit for controlling a light source that illuminates a display, said display driver circuit comprising:

an input terminal set operative to receive a plurality of data bits, each of said data bits associated with a different pixel of said display; and

detection logic operative to

read the value of each of said data bits,

determine whether each of said data bits has a value indicative of an off-state, and

generate a disable signal if each of said data bits has a value indicative of said off-state; and

wherein

said disable signal causes said light source to turn off.

16. A display driver circuit according to claim 15, further comprising a data planarizer operative to:

receive a plurality of multi-bit data words via said input terminal set, each of said multi-bit data words associated with a different pixel of said display; and

planarize the bits of said plurality of multi-bit data words according to bit plane, each of said bit planes containing bits of equal significance.

17. A display driver circuit according to claim 16, further comprising a light source controller, responsive to said disable signal, and operative to turn off said light source for a time period dependent on the significance of at least one of said bit planes.

18. A display driver circuit according to claim 17, wherein:

each of said data bits in a first bit plane have said value indicative of said off-state; and

said light source controller, responsive to said disable signal, is operative to turn off said light source for a time period greater than or equal to the significance of each bit in said first bit plane.

19. A display driver circuit according to claim 17, wherein:

each of said data bits in a first bit plane have said value indicative of said off-state;

said light source controller, responsive to said disable signal, is operative to

turn off said light source for a time period equal to the significance of each bit in said first bit plane, and

turn off said light source for a time period equal to the significance of each bit in a second bit plane;

said data bits in said first bit plane are sequential bits; and

each of said sequential bits indicates that the value of at least one data bit in said second bit plane is indicative of said off-state.

20. A display driver circuit according to claim 16, wherein said detection logic is further operative to:

determine whether each of the data bits in each of said bit planes has a value indicative of said off-state; and

generate a separate disable signal for particular ones of said bit planes where each of said data bits in said particular bit plane has a value indicative of said off-state.

21. A display driver circuit according to claim 20, wherein:

said detection logic is further operative to generate separate disable signals by setting a plurality of indicators to a predetermined value, said predetermined value indicating that each of the data bits in one of said bit planes has a value indicative of said off-state;

each of said indicators is associated with a different one of said bit planes; and

each of said indicators indicates whether each of said data bits in said associated bit plane has said value indicative of said off state.

22. A display driver circuit according to claim 15, further comprising a light source controller, responsive to said disable signal, and operative to turn said light source on in the absence of said disable signal.

23. A display driver circuit according to claim 15, wherein:

said input terminal set is operative to receive a second plurality of data bits, each of said second plurality of data bits associated with a different pixel of said display; and

said detection logic is operative to

read the value of each of said second plurality of data bits;

determine whether each of said second plurality of data bits has a value indicative of an off-state; and

generate a disable signal if each of said second plurality of data bits has said value indicative of said off-state.

24. A display driver circuit according to claim 15, wherein:

said input terminal set is operative to receive a second plurality of data bits, each of said second plurality of data bits associated with a different pixel of said display;

said light source controller is operative to keep said light source turned off for an additional time period dependent on the significance of at least one of said second plurality of bits; and

wherein

said plurality of data bits are sequential bits; and

said sequential bits indicate that the value of each of said second plurality of data bits is indicative of said off-state.

25. A display driver circuit according to claim 15, wherein:

said plurality of data bits is a plurality of sequential bits, each of said sequential bits associated with one of said pixels of said display; and

each of said sequential bits indicates the value of at least one other bit associated with said pixel.

26. A display driver circuit according to claim 15, wherein said light source includes a light-emitting diode (LED).

27. A display driver circuit according to claim 15, wherein said light source includes a laser.

28. A display driver circuit for controlling a light source, said display driver circuit comprising:

an input terminal set operative to receive a plurality of data bits, each of said data bits associated with a different pixel of said display;

means for reading the value of each of said data bits,

means for determining whether each of said data bits has a value indicative of an off-state, and

means for selectively turning off said light source based on the values of said plurality of data bits.