System and method for integrated, analog mode mirror devices

• US 20080273234A1
• Filed: 05/01/2007
• Published: 11/06/2008
• Est. Priority Date: 05/01/2007
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mehrl, David Joseph, Barker, Paul Gerald
• Application Number:
  US11/799,255
• Publication Number:
  US 20080273234A1
• Time in Patent Office: Days
• US Class Current: 359/223
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A system and method for integrated, analog mode mirror devices. A system containing integrated, analog mode mirror devices includes a damped digital micromirror device (DDMD) optically coupled to a light source and positioned in a light path of the light source, and a controller electrically coupled to the DDMD. The damped micromirrors move more slowly than undamped micromirrors, thereby enabling control of the position of the micromirrors by the controller, with the position being in a range of positions between a first stop position and a second stop position. The micromirror may be moved to a position when presented with a drive waveform that has been modulated by a value specifying the position. This enables the specifying and control of the position of the individual micromirrors in the DDMD.

Claims

1. A method for controlling a position of a micromirror, the method comprising:

receiving a value, wherein the position is based on the value and the position of the micromirror is between a first stop position and a second stop position;

determining a drive waveform based on the value; and

providing the drive waveform to the micromirror.

2. The method of claim 1, wherein the providing is repeated until a second value is received.

3. The method of claim 1, further comprising after the providing, receiving micromirror position feedback information, and wherein the determining is further based on the micromirror position feedback information.

4. The method of claim 1, wherein the position lies within a range of positions spanned by the first stop position and the second stop position and is inclusive of the first stop position and the second stop position.

5. The method of claim 1, wherein the determining comprises:

converting the value into a binary number; and

combining the binary number with a reference drive waveform.

6. The method of claim 5, wherein the combining comprises:

for each binary value in the binary number,

setting an associated portion of the reference drive waveform to about zero in response to a determining that the binary value is equal to zero, and

leaving unchanged the associated portion of the reference drive waveform in response to a determining that the binary value is equal to one.

7. The method of claim 5, wherein the reference drive waveform comprises N pulses with increasing voltage magnitude, wherein the voltage magnitude is expressible as:

V_bmax[2^i/2/2<sup>(N−

1)/2</sup>], for 0≦

i≦

N−

1,

where N is the number of bits used in the binary number, and V_bmax is a maximum voltage.

8. The method of claim 5, wherein the reference drive waveform comprises N pulses with increasing voltage on time, wherein the voltage on time is expressible as:

Time_max[2^i/2/2<sup>(N−

1)/2</sup>], for 0≦

i≦

N−

1,

where N is the number of bits used in the binary number, and Time_max is a maximum voltage on-time.

9. The method of claim 5, wherein the reference drive waveform comprises N pulses with increasing voltage magnitude and voltage on-time.

10. The method of claim 1, wherein the drive waveform is based on a scaled version of the value, and wherein the scaling of the value is reduced as the micromirror moves closer to the tilt angle.

11. A system comprising:

a first damped digital micromirror device (DDMD) optically coupled to a light source and positioned in a light path of the light source, the first DDMD comprising an array of micromirrors operating in a damping liquid, wherein the damping liquid retards the movement of the micromirrors; and

a controller electrically coupled to the first DDMD, the controller configured to provide drive waveforms to individual micromirrors in the first DDMD, wherein a drive waveform moves the micromirrors in the first DDMD to a position between a first stop position and a second stop position.

12. The system of claim 11, further comprising:

a beam splitter optically coupled to the first DDMD and positioned in the light path after the first DDMD, the beam splitter configured to split the light path into a second light path and a third light path; and

a sensor array optically coupled to the beam splitter and positioned in the second light path of the beam splitter and electrically coupled to the controller, the sensor array configured to provide electrical information based on sensed optical information.

13. The system of claim 12, wherein the sensor array provides electrical information related to the positions of the micromirrors in the first DDMD.

14. The system of claim 11, further comprising a second DDMD optically coupled to the light source and positioned in the light path after the first DDMD and electrically coupled to the controller, the second DDMD comprising a second array of micromirrors operating in a second damping liquid, wherein the second damping liquid retards the movement of the micromirrors in the second DDMD.

15. The system of claim 14, further comprising:

a second beam splitter optically coupled to the second DDMD and positioned in the light path after the second DDMD, the beam splitter configured to split the light path into a fourth light path and a fifth light path; and

a second sensor array optically coupled to the second beam splitter and positioned in the fourth light path of the second beam splitter and electrically coupled to the controller, the sensor array configured to provide electrical information based on sensed optical information.

16. The system of claim 14, further comprising:

a filter stop optically coupled to the first DDMD and positioned in the light path after the first DDMD, the filter stop configured to convert linear phase modulated light from the first DDMD into intensity modulated light; and

a spatial filter optically coupled to the second DDMD and positioned in the light path after the second DDMD, the spatial filter configured to eliminate extraneous orders of the intensity modulated light.

17. The system of claim 11, wherein at least one micromirror in the array of micromirrors operates in a bi-stable mode, moving between a first position and a second position, stopping only in either the first position or the second position, and wherein at least another micromirror in the array of micromirrors operates in an analog mode, moving between the first position and the second position, stopping about third position between the first position and the second position.

18. The system of claim 11, wherein the first DDMD comprises micromirrors selected from the group consisting of:

tilt-mode micromirrors, sag/piston-mode micromirrors, and combinations thereof.

19. A method of manufacturing a system, the method comprising:

installing a light source;

installing an optics system optically coupled to the light source and in a light path of the light source;

installing a damped digital micromirror device (DDMD) optically coupled to the optics system and in the light path after the optics system, wherein the DDMD comprises an array of micromirrors operating in a damping liquid; and

installing a controller electrically coupled to the DDMD.

20. The method of claim 19, further comprising:

installing a beam splitter optically coupled to the DDMD and in the light path after the DDMD; and

installing a sensor array in a light path of the beam splitter and electrically coupled to the controller.