Method and apparatus of grayscale image generation in monochrome display

• US 10,643,519 B2
• Filed: 07/24/2017
• Issued: 05/05/2020
• Est. Priority Date: 07/24/2017
• Status: Active Grant

• Current Assignee: Solomon Systech Limited
• Original Assignee: Solomon Systech Limited
• Inventors: Lee, Chi Wai, Lai, Chun Hung, Ng, Wai Hon, Lau, Yuen Pat, Leung, Ling Sum
• Primary Examiner(s): Yang, Kwang-Su
• Application Number:
  US15/657,310
• Publication Number:
  US 20190027084A1
• Time in Patent Office: 1,016 Days
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2340/08 Monochrome to colour transformation
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/04 for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 5/391 Resolution modifying circuits, e.g. variable screen formats

Abstract

A method is provided that allows the use of monochrome PMOLED display driver to generate grayscale patterns without the need to change the resolution of the 1-bit digital-to-analog converter (DAC) on the data line (SEG). The method further allows the elimination of extra frame buffer display memory needed by conventional techniques. This is achieved by swapping display memory space for display image pixel color (grayscale) depth in the expense of display resolution. The method further allows grayscale pattern data to be written into frame buffer only once without additional control from the host controller. The method further allows the dynamic application of grayscale on selectable whole or portion of a scan line such that full grayscale image display or a mixture of monochrome and grayscale image display in a single display panel is possible.

Claims

1. A method of grayscale image display signal driving in a monochrome display panel, comprising:

activating each scan line in T number of timeslots within each frame, wherein only one scan line is activated at any one timeslot; and

driving each data line by one of Y number of different driving signal waveforms during each timeslot within each frame, wherein each of the Y number of different driving signal waveforms corresponds to one possible pixel grayscale level,

wherein;

brightness of a pixel is determined by a sum of the driving signal waveforms during the activated scan line timeslots driven on a data line connected to the pixel, wherein T and Y are an integer greater than one, respectively;

grayscale image pixel gray level information is stored in a display memory space shared by image display data;

the display memory space is fixed for an original display resolution of the display panel such that the display resolution is decreased to accommodate the grayscale image pixel gray level information being stored in a portion of the display memory space reserved for the grayscale image pixel gray level information; and

the portion of the display memory space reserved for the grayscale image pixel gray level information is split into multiple parts corresponding to multiple areas distributed throughout the display panel.

2. The method of claim 1, wherein the activation of each scan line is in T number of consecutive timeslots within each frame.

3. The method of claim 1, wherein the activation of each scan line is in T number of non-consecutive timeslots within each frame.

4. The method of claim 1, wherein;

T is equal to two;

each data line is drived by one of the Y number of different driving signal waveforms during a first timeslot within each frame; and

each data line is drived by one of the Y number of different driving signal waveforms having magnitudes divided by a factor of Y during a second timeslot within each frame.

5. The method of claim 4, wherein the activation of each scan line is in T number of consecutive timeslots within each frame.

6. The method of claim 4, wherein the activation of each scan line is in T number of non-consecutive timeslots within each frame.

7. A passive matrix organic light-emitting diodes (PMOLED) display panel comprising a display driver configured to execute the method of claim 4.

8. A passive matrix organic light-emitting diodes (PMOLED) display panel comprising a display driver configured to execute the method of claim 1.

9. The method of claim 1, wherein;

the Y number of different driving signal waveforms are ON or OFF driving signal waveform cycles; and

brightness of a pixel is determined by total number of timeslots having ON driving signal waveform cycles driven on the data line connected to the pixel.

10. The method of claim 9, wherein all ON driving signal waveform cycles have identical signal waveform duty ratio and current amplitude.

11. The method of claim 10, wherein the activation of each scan line is in T number of consecutive timeslots within each frame.

12. The method of claim 10, wherein the activation of each scan line is in T number of non-consecutive timeslots within each frame.

13. A passive matrix organic light-emitting diodes (PMOLED) display panel comprising a display driver configured to execute the method of claim 10.

14. The method of claim 9, wherein the ON driving signal waveform cycles vary, in terms of signal waveform duty ratio or current amplitude, in specific order in different timeslots.

15. The method of claim 14, wherein the activation of each scan line is in T number of consecutive timeslots within each frame.

16. The method of claim 14, wherein the activation of each scan line is in T number of non-consecutive timeslots within each frame.

17. A passive matrix organic light-emitting diodes (PMOLED) display panel comprising a display driver configured to execute the method of claim 14.