Method for driving electro-optic displays

• US 10,276,109 B2
• Filed: 03/09/2017
• Issued: 04/30/2019
• Est. Priority Date: 03/09/2016
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Crounse, Kenneth R., Hoogeboom, Christopher L., Telfer, Stephen J.
• Primary Examiner(s): Cerullo, Liliana
• Application Number:
  US15/454,276
• Publication Number:
  US 20170263175A1
• Time in Patent Office: 782 Days
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• 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 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• 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
• CPC Class Codes: G09G 3/3446 with more than two electrodes controlling the modulating element

Abstract

A method for driving an electro-optic display having a front electrode, a backplane and a display medium positioned between the front electrode and the backplane, the method comprising of applying a first driving phase to the display medium, the first driving phase having a first signal and a second signal, the first signal having a first polarity, a first amplitude as a function of time, and a first duration, the second signal succeeding the first signal and having a second polarity opposite to the first polarity, a second amplitude as a function of time, and a second duration, such that the sum of the first amplitude as a function of time integrated over the first duration and the second amplitude as a function of time integrated over the second duration produces a first impulse offset. The method further comprising applying a second driving phase to the display medium, the second driving phase produces a second impulse offset, wherein the sum of the first and second impulse offset is substantially zero.

Claims

1. A method for driving an electro-optic display having a front electrode, a backplane and a display medium positioned between the front electrode and the backplane, the method comprising:

applying a first driving phase to the display medium, the first driving phase having a first signal and a second signal, the first signal having a first polarity, a first amplitude as a function of time, and a first duration, the second signal succeeding the first signal and having a second polarity opposite to the first polarity, a second amplitude as a function of time, and a second duration, such that the sum of the first amplitude as a function of time integrated over the first duration and the second amplitude as a function of time integrated over the second duration produces a first impulse offset; and

applying a second driving phase to the display medium, the second driving phase producing a second impulse offset;

wherein the first duration is determined by a ratio between the magnitude of the second impulse offset and the amplitude difference between the first amplitude and the second amplitude; and

wherein the sum of the first and second impulse offset is substantially zero.

2. The method of claim 1, wherein the first polarity is a negative voltage and the second polarity is a positive voltage.

3. The method of claim 1, wherein the first polarity is a positive voltage and the second polarity is a negative voltage.

4. The method of claim 1, wherein the duration of the first driving phase is different from that of the second driving phase.

5. The method of claim 1 wherein the display medium is an electrophoretic medium.

6. The method of claim 5 wherein the display medium is an encapsulated electrophoretic display medium.

7. The method of claim 5 wherein the electrophoretic display medium comprises an electrophoretic medium comprising a liquid and at least one particle disposed within said liquid and capable of moving therethrough on application of an electric field to the medium.

8. A method for driving an electro-optic display having a front electrode, a backplane, and a display medium positioned between the front electrode and the backplane, the method comprising:

applying a reset phase and a color transition phase to the display, the reset phase comprising;

applying a first signal having a first polarity, a first amplitude as a function of time, and a first duration on the front electrode;

applying a second signal having a second polarity opposite the first polarity, a second amplitude as a function of time, and a second duration during the first duration on the backplane;

applying a third signal having the second polarity, a third amplitude as a function of time, and a third duration preceded by the first duration on the front electrode;

applying a fourth signal having the first polarity, a fourth amplitude as a function of time, and a fourth duration preceded by the second duration on the backplane;

wherein the sum of the first amplitude as a function of time integrated over the first duration, and the second amplitude as a function of time integrated over the second duration, and the third amplitude as a function of time integrated over the third duration, and the fourth amplitude as a function of time integrated over the fourth duration produces an impulse offset designed to maintain a DC-balance on the display medium over the reset phase and the color transition phase.

9. The method of claim 8 wherein the reset phase erases previous optical properties rendered on the display.

10. The method of claim 8 wherein the color transition phase substantially changes the optical property displayed by the display.

11. The method of claim 8 wherein the first polarity is a negative voltage.

12. The method of claim 8 wherein the first polarity is a positive voltage.

13. The method of claim 8 wherein the impulse offset is proportional to a kickback voltage experienced by the display medium.

14. The method of claim 8 wherein the first duration and the second duration initiate at the same time.

15. The method of claim 8 wherein the fourth duration occurs during the third duration.

16. The method of claim 15 wherein the third duration and the fourth duration initiate at the same time.