Driving method for an electrophoretic display with accurate greyscale and minimizedaverage power consumption.

• US 20060262083A1
• Filed: 08/30/2004
• Published: 11/23/2006
• Est. Priority Date: 09/08/2003
• Status: Active Grant

• Current Assignee: Intertrust Technologies Corporation (Fidelio Acquisition Co LLC)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Johnson, Mark T., Henzen, Alex V., Kamer, Jan Van De, Zhou, Guofu
• Granted Patent: US 7,839,381 B2
• Time in Patent Office: Days
• US Class Current: 345/107
• CPC Class Codes: G09G 2310/02 Addressing, scanning or driving the display screen or processing steps related thereto
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/065 Waveforms comprising zero voltage phase or pause
• CPC Class Codes: G09G 2310/068 Application of pulses of alternating polarity prior to the drive pulse in electrophoretic displays
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167

Abstract

An image is updated on a bi-stable display (310) such as an electrophoretic display in successive frame periods by accessing data defining a set of voltage waveforms for the successive frame periods. At least a portion of the bi-stable display is driven during the successive frame periods according to the accessed data so that a longer frame period (FT, 1302, 1304, 1402, 1502, 1602, 1702, 1802) is used during at least a first portion of the voltage waveforms, and a shorter frame period (FT′) is used during at least a second portion of the voltage waveforms. For example, the longer frame period may be an elongated frame period, which is the longest period during which each of the voltage waveforms has a respective constant voltage value.

Claims

1. A method for updating at least a portion of a bi-stable display in successive frame periods, the method comprising:

accessing data defining at least one voltage waveform for the successive frame periods; and

driving the at least a portion of the bi-stable display (310) during the successive frame periods according to the accessed data so that at least one longer frame period (FT, 1302, 1304, 1402, 1502, 1602, 1702, 1802) is used during at least a first portion of the voltage waveforms, and at least one shorter frame period (FT′

) is used during at least a second portion of the voltage waveforms.

2. The method of claim 1, wherein:

the accessing data defining the at least one voltage waveform comprises accessing data defining a plurality of voltage waveforms.

3. The method of claim 2, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one longer frame period comprises at least one elongated frame period (1302, 1304, 1402, 1502, 1602, 1702, 1802), during which each of the voltage waveforms has a respective constant voltage value.

4. The method of claim 3, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one elongated frame period is the longest period during which each of the voltage waveforms has its respective constant voltage value.

5. The method of claim 3, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one elongated frame period occurs during a reset portion (RE) of the voltage waveforms.

6. The method of claim 3, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one elongated frame period occurs during a drive portion (DR, DR1) of the voltage waveforms.

7. The method of claim 2, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one shorter frame period occurs during at least a terminal portion of a drive portion (DR, DR1) of the voltage waveforms.

8. The method of claim 2, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one shorter frame period occurs during at least a shaking pulse portion (S1) of the voltage waveforms.

9. The method of claim 2, wherein:

the voltage waveforms include at least one rest portion (R, R1, R2) immediately prior to a frame period rate change in the successive frame periods.

10. The method of claim 2, wherein:

each of the voltage waveforms include first drive portions, and time-aligned second drive portions with a reduced range of voltage values.

11. The method of claim 2, wherein:

each of the voltage waveforms includes a drive portion for providing a direct image transition without reset to an optical rail state; and

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one shorter frame period is used during at least a terminal portion of the drive portion.

12. The method of claim 2, wherein:

the bi-stable display comprises an electrophoretic display.

13. A program storage device tangibly embodying a program of instructions executable by a machine to perform a method for updating at least a portion of a bi-stable display in successive frame periods, the method comprising:

accessing data defining a set of voltage waveforms for the successive frame periods; and

driving the at least a portion of the bi-stable display (310) during the successive frame periods according to the accessed data so that at least one longer frame period (FT, 1302, 1304, 1402, 1502, 1602, 1702, 1802) is used during at least a first portion of the voltage waveforms, and at least one shorter frame period (FT′

) is used during at least a second portion of the voltage waveforms.

14. The program storage device of claim 13, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one longer frame period comprises at least one elongated frame period (1302, 1304, 1402, 1502, 1602, 1702, 1802), during which each of the voltage waveforms has a respective constant voltage value.

15. The program storage device of claim 14, wherein:

the driving the at least a portion of the bi-stable display comprises driving the at least a portion of the bi-stable display so that the at least one elongated frame period is the longest period during which each of the voltage waveforms has its respective constant voltage value.

16. The program storage device of claim 13, wherein:

the bi-stable display comprises an electrophoretic display.

17. An display device, comprising:

a bi-stable display (310); and

a control (100) for updating at least a portion of the bi-stable display in successive frame periods by;

(a) accessing data defining a set of voltage waveforms for the successive frame periods, and (b) driving the at least a portion of the bi-stable display (310) during the successive frame periods according to the accessed data so that at least one longer frame period (FT, 1302, 1304, 1402, 1502, 1602, 1702, 1802) is used during at least a first portion of the voltage waveforms, and at least one shorter frame period (FT′

) is used during at least a second portion of the voltage waveforms.

18. The display device of claim 17, wherein:

the control drives the at least a portion of the bi-stable display by driving the at least a portion of the bi-stable display so that the at least one longer frame period comprises at least one elongated frame period (1302, 1304, 1402, 1502, 1602, 1702, 1802), during which each of the voltage waveforms has a respective constant voltage value.

19. The display device of claim 18, wherein:

the control drives the at least a portion of the bi-stable display by driving the at least a portion of the bi-stable display so that the at least one elongated frame period is the longest period during which each of the voltage waveforms has its respective constant voltage value.

20. The display device of claim 17, wherein:

the bi-stable display comprises an electrophoretic display.

21. A controller (330) comprising a processor and a program of instructions executable by the processor, the program of instructions comprising computer code device means for accessing data defining a set of voltage waveforms for successive frame periods during updating of at least a portion of a bi-stable display (310) and means for driving the at least a portion of the bi-stable display (310) during the successive frame periods according to the accessed data so that at least one longer frame period (FT, 1302, 1304, 1402, 1502, 1602, 1702, 1802) is used during at least a first portion of the voltage waveforms, and at least one shorter frame period (FT′

) is used during at least a second portion of the voltage waveforms.