Method and apparatus for increasing a perceived resolution of a display

• US 8,723,846 B2
• Filed: 08/22/2011
• Issued: 05/13/2014
• Est. Priority Date: 01/07/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Marshall, Stephen W., Allbright, Michael M., McDonald, Bill C.
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): ENGLISH, ALECIA DIANE
• Application Number:
  US13/214,772
• Publication Number:
  US 20110304596A1
• Time in Patent Office: 995 Days
• Field of Search: 345/32, 345/205
• US Class Current: 345/205
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/007 Use of pixel shift techniques, e.g. by mechanical shift of the physical pixels or by optical shift of the perceived pixels
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H04N 2005/7466 Control circuits therefor
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]

Abstract

According to one embodiment, a method of increasing a perceived resolution of a display includes directing light at a optical dithering element and repeatedly transitioning the optical dithering element from a first position to a second position and then back to the first position such that the mirror alternately reflects light to a first position on the display and then to a second position on the display. Each transition of the mirror includes controlling any overshoot or ringing in the position of the optical dithering element by providing a predetermined drive signal to the optical dithering element to smoothly accelerate and decelerate the element during the traverse between the first and second positions.

Claims

1. A method of increasing a perceived resolution of a display comprising:

directing light at an optical dithering element; and

repeatedly transitioning the optical dithering element from a first position to a second position and then back to the first position such that the optical dithering element alternately directs light to a first position on the display and then to a second position on the display;

wherein each transition of the optical dithering element comprises controlling any overshoot or ringing in the position of the optical dithering element by providing a predetermined control signal to the optical dithering element;

wherein a resonant response period is defined as a time period between the beginning of a transition from the first position to the second position and the beginning of the next subsequent transition from the second position to the first position; and

wherein the predetermined control signal comprises;

a step pulse having a first magnitude and having a width of approximately twenty percent of the resonant response period; and

a quench pulse immediately following the step pulse, the quench pulse having a magnitude equal to the first magnitude but opposite in direction and having a width of approximately fourteen percent of the resonant response period.

2. The method of claim 1, wherein the predetermined control signal is dependent on a position versus time response of the optical dithering element of a previous transition.

3. The method of claim 1, wherein the optical dithering element has a spring system associated therewith and wherein the predetermined control signal is dependent on a natural frequency of the combination of the optical dithering element and the spring system.

4. The method of claim 1, wherein the optical dithering element has a spring system associated therewith and wherein the predetermined control signal is dependent on a mechanical quality factor (Q) of a spring mass system comprising the combination of the optical dithering element and the spring system.

5. The method of claim 1, wherein the predetermined control signal is determined by simulation of the position over time of the optical dithering element.

6. The method of claim 1, wherein directing light comprises directing light by a digital micro-mirror imaging device.

7. The method of claim 1, wherein directing light comprises directing different colors of light at different time periods and when repeatedly transitioning the optical dithering element comprises transitioning the optical dithering element when no color other than blue is directed at the optical dithering element.

8. The method of claim 1, wherein the position versus time response of the optical dithering element for a transition from the first position to the second position and then a transition from the second position to the first position is generally trapezoidal.

9. The method of claim 1, wherein the width of the quench pulse is based at least in part on a position versus time response of the optical dithering element of a prior transition.

10. The method of claim 1, wherein the magnitude of a delay associated with the quench pulse is based at least in part on a position versus time response of the optical dithering element of a prior transition.

11. The method of claim 1, further comprising automatically adjusting the predetermined control signal in response to any overshoot that occurs during transition between the first and second positions of the optical dithering element during previous transitions.

12. The method of claim 11, wherein automatically adjusting comprises increasing an amplitude of the predetermined control signal to produce a desired position versus time response for the optical dithering element and then decreasing the amplitude to maintain the desired position versus time response for the optical dithering element.

13. The method of claim 1, wherein the optical dithering element comprises a mirror;

transitioning the optical dithering element comprises transitioning the mirror such that the mirror alternately reflects light to the first position on the display and then to the second position on the display; and

wherein each transition of the mirror comprises controlling any overshoot or ringing in the position of the mirror.