Display region architectures

• US 7,893,919 B2
• Filed: 01/21/2005
• Issued: 02/22/2011
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sampsell, Jeffrey B., Kothari, Manish
• Primary Examiner(s): Hjerpe; Richard
• Assistant Examiner(s): Shapiro; Leonid
• Application Number:
  US11/040,822
• Publication Number:
  US 20060066640A1
• Time in Patent Office: 2,223 Days
• Field of Search: 345/108, 345/87, 345/55, 345/204
• US Class Current: 345/108
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

A bit depth of a pixel comprising multiple display elements, such as interferometric modulators, may be increased through the use of display elements having different intensities, while the lead count is minimally increased. An exemplary pixel with at least one display element having an intensity of 0.5 and N display elements each having an intensity of one can provide about 2N+1 shades (e.g., 0, 0.5, 1.0, 1.5, 2.0, [N+0.5]). In comparison, a pixel having N display elements, each having an intensity of one, can only provide about N+1 shades (e.g., 0, 1, 2, . . . , N). Thus, using at least one display element having an intensity lower than the intensity of each of the other display elements increases the number of shades provided by the pixel by an approximate factor of two and increases the bit depth of the pixel, while minimizing the number of additional leads.

Claims

1. A pixel having a bit depth, the pixel comprising:

a plurality of substantially equally sized display elements each having an “

on”

position and an “

off”

position, wherein the display elements each emit visible light when in the “

on”

position, the plurality of substantially equally sized display elements includes a first group of display elements and a second group of display elements, the display elements of the first group each controlled by n₁ bits of a driver signal and having an intensity of a predetermined value when in the “

on”

position and the display elements of the second group each controlled by n₂ bits of the driver signal and having an intensity of a fraction of the predetermined value when in the “

on”

position, an intensity of the pixel being equal to an intensity of each of the plurality of display elements in the “

on”

position;

wherein the pixel is configured such that the first group of display elements provide a brighter output level than that of the second group of display elements, the quantity n₁ being less than the quantity n₂ such that the bit depth of the pixel comprises a coarse gradation of shade provided by the first group of display elements and a finer gradation of shade provided by the second group of display elements.

2. The pixel of claim 1, further comprising a third group of display elements, the display elements of the third group each having an intensity of less than the fraction of the predetermined value when in the “

on”

position, the intensity of the pixel being equal to an intensity of each of the plurality of display elements in the “

on”

position.

3. The pixel of claim 1, wherein an intensity of at least one of the display elements of the second group is configured to change according to a driver signal.

4. The pixel of claim 1, wherein the display elements of the second group include masking that reduces the aperture of the display elements.

5. The pixel of claim 1, wherein at least one of the display elements of the second group has an intensity of one-half the predetermined value.

6. The pixel of claim 1, wherein at least one of the display elements of the second group has an intensity of one-quarter the predetermined value.

7. The pixel of claim 1, wherein the display elements of the second group are masked to provide non-linear increments of intensity up to the predetermined value.

8. The pixel of claim 7, wherein the second group comprises at least four display elements, the at least four display elements having respective intensities of 0.1, 0.2, 0.4, and 0.8 of the predetermined value.

9. The pixel of claim 1, wherein the n₁ bits controlling the first group of display elements are more significant in the driver signal than the n₂ bits controlling the second group of display elements.

10. The pixel of claim 1, wherein at least some of the display elements comprises an interferometric modulator.

11. A display device comprising:

a plurality of pixels, each of the pixels configured to have an aperture and a bit depth of p and comprising a plurality of sub-regions;

a first plurality of sub-regions configured to have a first aperture and responsive to K bits of the p bit depth of the pixel; and

a second plurality of sub-regions configured to have a second aperture and responsive to at least some of p−

K bits of the p bit depth of the pixel;

wherein the first aperture of the first plurality of sub-regions covers at least about 85% of the aperture of the pixel while the first plurality of sub-regions are controlled by the K bits that are less than or equal to half of the bit depth p.

12. The display device of claim 11, wherein the plurality of sub-regions comprises 2^K+2−

4 sub-regions.

13. The display device of claim 11, wherein the first aperture of the first plurality of sub-regions covers more than about 90 percent of the aperture of the pixel.

14. The display device of claim 13, wherein the first aperture of the first plurality of sub-regions covers more than about 98 percent of the aperture of the pixel.

15. The display device of claim 11, wherein the second plurality of sub-regions comprises one or more rows of sub-regions disposed between rows of the sub-regions of the first plurality of sub-regions.

16. The display device of claim 11, wherein the second plurality of sub-regions comprises one or more columns of sub-regions disposed between columns of the sub-regions of the first plurality of sub-regions.

17. The display device of claim 11, wherein the second plurality of sub-regions comprises one or more rows of sub-regions disposed between rows of the sub-regions of the first portion of sub-regions and one or more columns of sub-regions disposed between columns of the sub-regions of the first portion of sub-regions.

18. The display device of claim 11, wherein the second plurality of sub-regions are controlled by the p−

K bits.

19. The display device of claim 11, wherein the K bits controlling the first plurality of sub-regions are more significant than the p−

K bits controlling the second plurality of sub-regions.

20. The display device of claim 11, wherein at least some of the plurality of pixels comprises one or more interferometric modulator elements.