Liquid crystal display reordered inversion

• US 8,552,957 B2
• Filed: 08/21/2009
• Issued: 10/08/2013
• Est. Priority Date: 02/02/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven Porter
• Primary Examiner(s): Chow, Van
• Application Number:
  US12/545,763
• Publication Number:
  US 20100195004A1
• Time in Patent Office: 1,509 Days
• Field of Search: None
• US Class Current: 345/100
• CPC Class Codes: G09G 2310/0213 controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general

Abstract

Methods and apparatus for switching the voltages supplied to the electrodes of pixels disposed within a liquid crystal display device. By reducing the frequency associated with an alternating voltage supplied to a first set of liquid crystal electrodes, the power required to drive the liquid crystal display device can be reduced. At the same time, a reordered schedule for updating rows of pixels in the liquid crystal display device can provide improved image quality.

Claims

1. A method of updating rows of pixels in a display panel, the method comprising:

assigning rows of pixels in the display panel to one of a plurality of update sets, each update set including a sequence of rows such that each row in the sequence is separated from a next row in the sequence by at least one row;

applying a common voltage to a set of electrodes in the display panel, the common voltage adapted to switch between two voltage levels; and

updating the pixels in the rows of an update set each time the common voltage applied to the set of electrodes switches voltage levels, wherein at least one row in one of the plurality of update sets updates before another row in the same update set updates a second time.

2. The method of claim 1, each update set having a same number of rows.

3. The method of claim 1, each update set including a sequence of either all even rows or all odd rows.

4. The method of claim 3, further comprising:

assigning only first and second update sets, each update set including a sequence of either all even rows or all odd rows; and

updating the pixels in the rows of one update set before updating the pixels in the rows of the other update set.

5. The method of claim 1, further comprising updating the pixels in the rows of an update set by modifying a gate pulse sequence of the display panel.

6. The method of claim 5, further comprising modifying the gate pulse sequence within a display driver chip.

7. The method of claim 5, further comprising modifying the gate pulse sequence via a gate driver circuit.

8. A display apparatus, comprising:

one or more display driver circuits communicatively couplable to an array of display pixels in a display panel, the one or more display driver circuits capable of

assigning rows of pixels in the display panel to one of a plurality of update sets, each update set including a sequence of rows such that each row in the sequence is separated from a next row in the sequence by at least one row,

applying a common voltage to a set of electrodes in the display panel, the applied voltage adapted to switch between two voltage levels, and

updating the pixels in the rows of an update set each time the voltage applied to the electrodes switches voltage levels, wherein at least one row in one of the plurality of update sets updates before another row in the same update set updates a second time.

9. The display apparatus of claim 8, the one or more display driver circuits further configured for assigning the rows of pixels in the display panel to one of a plurality of update sets such that each update set has a same number of rows.

10. The display apparatus of claim 8, the one or more display driver circuits further configured for assigning the rows of pixels in the display panel to one of a plurality of update sets such that each update set includes a sequence of either all even rows or all odd rows.

11. The display apparatus of claim 10, the one or more display driver circuits further configured for:

assigning only first and second update sets, each update set including a sequence of either all even rows or all odd rows; and

updating the pixels in the rows of one update set before updating the pixels in the rows of the other update set.

12. The display apparatus of claim 8, the one or more display driver circuits further configured for updating the pixels in the rows of an update set by modifying a gate pulse sequence of the display panel.

13. The display apparatus of claim 12, the one or more display driver circuits further configured for modifying the gate pulse sequence within a display driver chip.

14. The display apparatus of claim 12, the one or more display driver circuits further configured for modifying the gate pulse sequence via a gate driver circuit.

15. The display apparatus of claim 8, the one or more display driver circuits further comprising a set of gate driver circuits disposed upon an electrically insulative substrate.

16. The display apparatus of claim 8, further comprising:

the display panel communicatively coupled to the one or more display driver circuits, the display panel including the array of pixels arranged into a plurality of rows, each pixel including a common electrode and an individually addressable pixel electrode, the common electrodes tied to a common alternating voltage source.

17. The display apparatus of claim 16, wherein at least a portion of the array of pixels are adapted to function as capacitive touch sensors in a touch sensor panel.

18. The display apparatus of claim 17, wherein the touch sensor panel is incorporated within a computing system.

19. The display apparatus of claim 16, wherein the common alternating voltage source is adapted to switch voltages at a constant frequency, and wherein the frequency is selected so as to attain a desired level of image quality.