Pixel border for improved viewability of a display device

• US 6,961,029 B1
• Filed: 11/08/2000
• Issued: 11/01/2005
• Est. Priority Date: 11/08/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Palm, Inc. (TCL Technology Group Corp.)
• Inventors: Canova, Francis James Jr., Noesen, Katherine, Blair, Richard
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): CASCHERA, ANTONIO A
• Application Number:
  US09/709,142
• Time in Patent Office: 1,819 Days
• Field of Search: 345/55, 345/92, 345/864, 345/30, 345/87, 715/864, 348/245
• US Class Current: 345/55
• 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 including a pixel border of width x and located around the edge locations of the matrix for improved viewability. In particular, 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 in which images are generated from a frame buffer memory. In one embodiment, the pixels of the border are “dummy pixels” each containing a red, a green and a blue subpixel. Each subpixel has a color filter and is manufactured with a “dummy” transistor which operates to fix open the subpixels thereby allowing a predetermined amount of “white” color brightness through the dummy pixels. In one implementation, the brightness amount is approximately 80–95 percent of the saturation brightness for the display screen. The pixel border is useful for increasing viewability of characters that are displayed along the edge of the LCD matrix area in which images are generated from a frame buffer memory. The pixel border is particularly useful for these edge displayed characters when the background color is white and the characters are generated using a non-white color. The pixel border is also advantageous in that it can be used with conventional character generation processes of the operating system of the computer used to drive the display screen. 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 matrix of independently controllable pixels comprising m rows and n columns of discrete pixels, said matrix for generating an image therein by light modulation and wherein said image is representative of information stored in a frame buffer memory; and

a pixel border having a predetermined width, said pixel border surrounding said matrix of independently controllable discrete pixels and comprising dummy pixels, wherein each dummy pixel is analogous to a pixel of said matrix but without containing any active element driven by a driver circuit and not capable of modification, and wherein said dummy pixels allow light to pass through to improve contrast of edge-displayed images of said matrix and to match the background pixel color of said matrix of independently controllable pixels.

2. A display unit as described in claim 1 and further comprising a back lighting element for illuminating said matrix and said pixel border.

3. A display unit as described in claim 2 wherein each pixel of said matrix comprises:

a red subpixel having a first active element;

a green subpixel having a second active element; and

a blue subpixel having a third active element.

4. A display unit as described in claim 3 wherein each dummy pixel of said matrix comprises:

a red sub-dummy-pixel having a first active element;

a green sub-dummy-pixel having a second active element; and

a blue sub-dummy-pixel having a third active element.

5. A display unit as described in claim 1 wherein said predetermined width is two pixels.

6. A display unit as described in claim 1 wherein said matrix comprises 160 rows and 160 columns of discrete pixels.

7. A display unit as described in claim 1 wherein said matrix is fabricated using thin film transistor liquid crystal display technology.

8. A portable electronic device comprising:

a processor coupled to a bus;

a memory unit coupled to said bus;

a user input device coupled to said bus; and

a display unit coupled to said bus and comprising;

a matrix of independently controllable pixels comprising m rows and n columns of discrete pixels, said matrix for generating an image therein by light modulation and wherein said image is representative of information stored in a frame buffer memory; and

a pixel border having a predetermined width, said pixel border surrounding said matrix of independently controllable discrete pixels and comprising dummy pixels, wherein each dummy pixel is analogous to a pixel driven by a driver circuit and not capable of modification, and wherein said dummy pixels allows light to pass through to improve contrast of edge-displayed images of said matrix and to match the background pixel color of said matrix of independently controllable pixels.

9. A portable electronic device as described in claim 8 further comprising a back lighting element for illuminating said matrix and said pixel border.

10. A portable electronic device as described in claim 9 wherein each pixel of said matrix comprises:

a red subpixel having a first active element;

a green subpixel having a second active element; and

a blue subpixel having a third active element.

11. A portable electronic device as described in claim 10 wherein each dummy pixel of said matrix comprises:

a red sub-dummy-pixel having a first active element;

a green sub-dummy-pixel having a second active element; and

a blue sub-dummy-pixel having a third active element.

12. A portable electronic device as described in claim 8 wherein said predetermined width is two pixels.

13. A portable electronic device as described in claim 8 wherein said matrix comprises 160 rows and 160 columns of discrete pixels.

14. A portable electronic device as described in claim 8 wherein said matrix is fabricated using thin film transistor liquid crystal display technology.

15. A display unit comprising:

a matrix of independently controllable pixels comprising m rows and n columns of discrete pixels, said matrix for generating an image therein by light modulation and wherein said image is representative of information stored in a frame buffer memory and wherein each pixel of said matrix comprises a respective active element and respective filter elements;

a pixel border having a predetermined width, said pixel border surrounding said matrix of independently controllable discrete pixels and comprising dummy pixels, wherein each dummy pixel comprises respective filter elements without any active element driven by a driver circuit and not capable of modification, and wherein said dummy pixels allows light to pass through to improve contrast of edge-displayed images of said matrix and to match the background pixel color of said matrix of independently controllable pixels; and

a back lighting element for illuminating said matrix and said pixel border.

16. A display unit as described in claim 15 wherein said respective filter elements of each pixel of said matrix comprises:

a red filter;

a green filter; and

a blue filter.

17. A display unit as described in claim 16 wherein said respective filter elements of each dummy pixel of said matrix comprises:

a red filter;

a green filter; and

a blue filter.

18. A display unit as described in claim 15 wherein said predetermined width is two pixels.

19. A display unit as described in claim 15 wherein said matrix comprises 160 rows and 160 columns of discrete pixels.

20. A display unit as described in claim 15 wherein said matrix is fabricated using thin film transistor liquid crystal display technology.