Method and apparatus for increasing a perceived resolution of a display

• US 7,336,290 B2
• Filed: 01/07/2004
• Issued: 02/26/2008
• Est. Priority Date: 01/07/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: McDonald, Bill C., Allbright, Michael M., Marshall, Stephen W.
• Primary Examiner(s): Dharia; Prabodh
• Application Number:
  US10/752,858
• Publication Number:
  US 20050146540A1
• Time in Patent Office: 1,511 Days
• Field of Search: 345/698, 345/204, 345/107, 345/81, 345/690, 345/87, 345/88, 345/102, 345/697, 345/440, 345/98, 345/63, 345/161, 345/84, 359/813, 359/291, 359/708, 250/559.13, 250/559.12, 735/142.6, 353/30, 348/218.1, 348/742, 356/459, 356/437, 389/813
• US Class Current: 345/698
• 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 for increasing a perceived resolution of a display comprising:

modulating light by a digital micromirror device and directing the modulated light to an optical dithering element;

repeatedly transitioning the optical dithering element between two positions such that light received from the digital micro-mirror device is alternately reflected to two different locations on the display, thereby increasing the perceived resolution of the display; and

controlling any overshoot or ringing in the transitions by providing a predetermined control signal, the predetermined control signal comprising a step pulse immediately followed by a quench pulse, the step pulse and quench pulse having approximately the same magnitude but opposite signs, the magnitude and width of the quench pulse and the step pulse being independent of any position feedback of the optical dithering element during the transition in which the predetermined control signal is applied.

2. The method of claim 1, wherein the predetermined control signal is dependent on position feedback of the optical dithering element from previous transitions of the optical dithering element.

3. A system for displaying an image on display comprising:

a light modulator operable to provide light indicative of an image to be displayed on the display;

an optical dithering element operable to receive light from the light modulator and direct the received light at the display;

an actuator system operable to selectively position the optical dithering element such that the directed light is directed to a desired position of the display; and

a controller operable to control the actuator system and further operable to provide a predetermined control signal to the actuator such that the mirror repeatedly transitions between a plurality of positions to increase the perceived resolution on the display, the control signal controlling any overshoot in transitioning between plurality of positions; and

wherein the predetermined control signal is independent of any feedback of the current position of the optical dithering element during a current transition.

4. The system of claim 3, wherein the light modulator is a digital micro-mirror device.

5. The system of claim 3, wherein the actuator system comprises at least one voice coil.

6. The system of claim 3, wherein the predetermined control signal comprises a quench pulse.

7. The system of claim 3 wherein the predetermined control signal is dependent on a position versus time response of the optical dithering element on a previous transition.

8. The system of claim 3, wherein the light modulator is further operable to direct different wavelengths of light at different time periods and wherein the predetermined control signals operate to cause transitions between the plurality of positions only when blue light, if any, is provided to the mirror.

9. The system of claim 3, wherein the predetermined control signal is operable in combination with the actuator to effect a position versus time response of the optical dithering element from a first position to a second position that is generally trapezoidal.

10. The system of claim 6, 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 at a previous transition.

11. The system of claim 3, and further comprising a position sensor operable to provide a feedback signal indicative of the position of the optical dithering element and wherein the controller is operable to adjust the predetermined control signal in response to any overshoot or ringing occurring in previous transitions.

12. A method for increasing the perceived resolution of a display comprising:

sequentially providing light of a plurality of different colors for integration by a viewer'"'"'s eye to produce a desired color; and

repeatedly redirecting the sequentially provided light between a plurality of positions on the display by repeatedly transitioning the position of an optical dithering element, only during a time period designated for transmission of a light of a selected order, if any.

13. The method of claim 12, wherein sequentially providing light of a plurality of different colors comprises providing red, green, blue, and white and wherein the transitioning does not occur during transmission of red, green, or white light.

14. The method of claim 12, wherein sequentially providing light of a plurality of different colors comprising providing blue light, and wherein transitioning occurs during a time period designated for transmissions of blue light.