Controllable pixel border for improved viewability of a display device

• US 7,362,338 B1
• Filed: 11/27/2000
• Issued: 04/22/2008
• Est. Priority Date: 11/08/2000
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Palm, Inc. (TCL Technology Group Corp.)
• Inventors: Gettemy, Shawn, Canova, Francis James Jr., Flores, Roger
• Primary Examiner(s): WANG, JIN CHENG
• Application Number:
  US09/724,197
• Time in Patent Office: 2,703 Days
• Field of Search: 345/636, 345/629, 345/698, 345 55- 67, 345/555, 345/581, 345/598
• US Class Current: 345/629
• CPC Class Codes: G02F 1/133388 with constructional differences between the display region and the peripheral region
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: G09G 2310/0232 Special driving of display border areas
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A display device having a display matrix (m+2x by n+2x) including an active, e.g., controllable, pixel border located around the edge locations of a frame buffer matrix for improved character viewability. The border can be several pixels wide, e.g., 1<x<5. In one embodiment, the border is two pixels wide and surrounds a liquid crystal display (LCD) matrix area having (m×n) pixels that are controlled by a frame buffer memory. In one embodiment, the pixels of the border are active pixels and each contain a red, a green and a blue subpixel. The pixel border is useful for increasing viewability, e.g., contrast, of characters that are displayed along the edge of the LCD matrix area in a frame buffer region. The invention includes a border attribute register for containing a color attribute and a brightness attribute, in one embodiment. The border attribute register can be set by an operating system command and can be read by a timing generator which generates the appropriate signals for controlling the border pixels. These signals are generated during special periods which otherwise carry invalid data with respect to the frame buffer matrix. In this way, the invention is backward compatible with application programs that use only the frame buffer memory region. Therefore, the active pixel border is advantageous in that it can be used with conventional character generation and display processes and formats. In one embodiment, the novel display can be used within a portable computer system or other portable electronic device.

Claims

1. A display unit comprising:

a display panel comprising a pixel matrix comprising;

a rectangular pixel frame buffer region; and

a fixed, active pixel border region comprising pixels permanently dedicated to displaying a border attribute, wherein said fixed, active pixel border region surrounds said rectangular pixel frame buffer region on four sides of said rectangular pixel frame buffer region and comprises a width in the range of two to 128 pixels;

a frame buffer memory for containing image data for generating an image within said frame buffer region;

a border attribute register dedicated for containing said border attribute, wherein said border attribute is automatically selected to provide viewing contrast with image data located near said border region, and wherein said border attribute comprises color information for each pixel in said fixed, active pixel border region, and wherein said border attribute is equal to a background attribute currently being displayed; and

a display controller coupled to said frame buffer memory, coupled to receive said border attribute from said border attribute register, and coupled to control said display panel, said display controller for generating a first set of signals for rendering said image within said frame buffer region and for generating a second set of signals for displaying said border attribute within said fixed, active border region.

2. The display unit as described in claim 1 wherein said second set of signals are generated within invalid timing windows with respect to said frame buffer region.

3. The display unit as described in claim 1 wherein a first portion of said second set of signals are generated in an invalid horizontal timing window that commences x clock cycles before valid data for said frame buffer region commences and wherein a second portion of said second set of signals are generated in an invalid horizontal timing window that ends x clock cycles after valid data for said frame buffer region completes.

4. The display unit as described in claim 3 wherein a third portion of said second set of signals are generated in an invalid vertical timing window that commences x horizontal pulses before a first valid horizontal line commences of a frame and wherein a fourth portion of said second set of signals are generated in an invalid vertical timing window that ends x horizontal pulses after the end of the last valid horizontal line of said frame.

5. The display unit as described in claim 1, wherein said border attribute of said border region comprises a color attribute.

6. The display unit as described in claim 1 wherein said display panel is a thin film transistor liquid crystal display panel.

7. The display unit as described in claim 1 wherein said frame buffer region comprises 160 rows and 160 columns of pixels.

8. The display unit as described in claim 1 further comprising a background display attribute register and wherein, by default, said border attribute register is equal to said background attribute register.

9. A display unit comprising:

a display panel comprising a pixel matrix comprising;

a rectangular pixel frame buffer region; and

a fixed, active pixel border region comprising pixels permanently dedicated to displaying a border attribute, wherein said fixed, active pixel border region surrounds said rectangular pixel frame buffer region on four sides of said rectangular pixel frame buffer region including top, bottom, right and left border regions, wherein said fixed, active pixel border region comprises a width in the range of two to ten pixels;

a frame buffer memory for containing character data for generating character images within said frame buffer region;

a border attribute register dedicated for containing said border attribute for said border region, wherein said border attribute is automatically selected to provide viewing contrast with character images located near said border region, and wherein said border attribute comprises color information for each pixel in said fixed, active pixel border region, and wherein said border attribute is equal to a background attribute; and

a display controller coupled to said frame buffer memory, coupled to receive said border attribute of said border attribute register, and coupled to control said display panel, said display controller for generating a first set of signals for rendering said character images within said rectangular pixel frame buffer region wherein said first set of signals comprises vertical and horizontal invalid timing windows and wherein said display controller is also for generating a second set of signals for displaying said border attribute within said fixed, active pixel border region.

10. The display unit as described in claim 9 wherein said second set of signals are generated within said vertical and horizontal invalid timing windows.

11. The display unit as described in claim 9 wherein said top and bottom border regions are rendered during said vertical invalid timing windows and wherein said right and left border regions are rendered during said horizontal invalid timing windows.

12. The display unit as described in claim 9 wherein said display attribute comprises a color attribute.

13. The display unit as described in claim 9 wherein said display panel is a thin film transistor liquid crystal display panel.

14. The display unit as described in claim 9 wherein said frame buffer region comprises 160 rows and 160 columns of pixels.

15. The display unit as described in claim 9 further comprising a background display attribute register and wherein, by default, said border attribute register is equal to said background attribute register.

16. A handheld device comprising:

a processor;

a memory unit coupled to said processor; and

a display unit coupled to said processor and comprising;

a display panel comprising a pixel matrix comprising;

a rectangular pixel frame buffer region; and

a fixed, active pixel border region comprising pixels permanently dedicated to displaying a border attribute, wherein said fixed, active pixel border region surrounds said rectangular pixel frame buffer region on four sides of said rectangular pixel frame buffer region and comprises a width in the range of two to five pixels;

a frame buffer memory for containing image data for generating an image within said rectangular pixel frame buffer region;

a border attribute register dedicated for containing said border attribute for said fixed, active border region, wherein said border attribute is automatically selected to provide viewing contrast with image data located near said fixed, active border region, and wherein said border attribute comprises color information, and wherein said border attribute is equal to a background attribute currently being displayed; and

a display controller coupled to said frame buffer memory, coupled to receive said border attribute from said border attribute register, and coupled to control said display panel, said display controller for generating a first set of signals for rendering said image within said rectangular pixel frame buffer region and for generating a second set of signals for displaying said border attribute within said fixed, active border region.

17. The handheld device as described in claim 16 wherein said second set of signals are generated within video timing windows that contain invalid data with respect to said frame buffer region.

18. The handheld device as described in claim 16 wherein a first portion of said second set of signals are generated x clock cycles before valid data for said frame buffer region commences and wherein a second portion of said second set of signals are generated x clock cycles after valid data for said frame buffer region completes.

19. The handheld device as described in claim 16 wherein said display attribute comprises a color attribute.

20. The handheld device as described in claim 16 wherein said display panel is a thin film transistor liquid crystal display panel.

21. The handheld device as described in claim 16 further comprising a background display attribute register and wherein, by default, said border attribute register is equal to said background attribute register.