Digital micro-mirror device having improved contrast and method for the same

• US 7,184,201 B2
• Filed: 11/02/2004
• Issued: 02/27/2007
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Duncan, Walter M.
• Primary Examiner(s): Mack; Ricky
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US10/980,363
• Publication Number:
  US 20060092497A1
• Time in Patent Office: 847 Days
• Field of Search: 359/291, 359/290, 359/292, 359/295, 359/298, 359/223, 359/224, 359/245, 359/248
• US Class Current: 359/321
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 5/22 Absorbing filters G02B5/201 - G02B5/208 take precedence

Abstract

According to one embodiment of the present invention, a digital micro-mirror device having improved contrast and a method for the same are provided. The digital micro-mirror device includes a plurality of current-carrying conductors on an upper surface of a substrate, each current-carrying conductor having an upper surface; a low-reflectivity metal disposed upon the upper surfaces of the current-carrying conductors; first and second micro-mirrors forming an aperture above the substrate; and wherein the low-reflectivity metal disposed upon on the upper surfaces of the current-carrying conductors reduces reflection of light received through the aperture by the current-carrying conductors.

Claims

1. A digital micro-mirror device having improved contrast, comprising:

a plurality of current-carrying conductors on an upper surface of a substrate, each current-carrying conductor having an upper surface;

a low-reflectivity metal selected from the group consisting of titanium, tungsten, vanadium, and tantalum disposed upon the upper surfaces of the current-carrying conductors;

first and second micro-mirrors forming an aperture above the substrate; and

wherein the low-reflectivity metal disposed upon on the upper surfaces of the current-carrying conductors reduces reflection of light received through the aperture by the current-carrying conductors.

2. The device of claim 1, wherein the low-reflectivity metal comprises a multilayer stack structure.

3. A digital micro-mirror device having improved contrast, comprising:

a plurality of current-carrying conductors on an upper surface of a substrate, each current-carrying conductor having an upper surface;

a low-reflectivity metal disposed upon the upper surfaces of the current-carrying conductors;

first and second micro-mirrors forming an aperture above the substrate; and

wherein the low-reflectivity metal disposed upon on the upper surfaces of the current-carrying conductors reduces reflection of light received through the aperture by the current-carrying conductors.

4. The device of claim 3, wherein the low-reflectivity metal comprises titanium, tungsten, vanadium, or tantalum.

5. The device of claim 3, wherein the low-reflectivity metal has a low absorption coefficient.

6. The device of claim 3, wherein the low-reflectivity metal has a reflectivity below about 0.6 for wavelengths of light from about 0.4 micrometers to about 0.7 micrometers.

7. The device of claim 3, wherein the low-reflectivity metal has a k value below about 3.5 for wavelengths of light from about 0.2 micrometers to about 0.8 micrometers.

8. The device of claim 3, wherein the low-reflectivity metal forms an ionic compound when reacted with an element in a headspace of the digital micro-mirror device.

9. The device of claim 3, wherein the low-reflectivity metal forms a compound having a low partial pressure when reacted with an element in a headspace of the digital micro-mirror device.

10. The device of claim 3, wherein the low-reflectivity metal comprises a multilayer stack structure.

11. The device of claim 10, wherein the low-reflectivity metal is at least partially transmissive.

12. A method for improving the contrast of a digital micro-mirror device, comprising:

receiving light through an aperture formed by a first micro-mirror and a second micro-mirror positioned above a substrate of a digital micro-mirror device, the substrate having a plurality of current-carrying conductors on an upper surface of the substrate, each current-carrying conductor having a low-reflectivity metal disposed upon an upper surface of the current-carrying conductor;

allowing light received through the aperture to contact the low-reflectivity metal; and

at least partially reducing the reflection of the light received through the aperture by the low-reflectivity metal.

13. The method of claim 12, wherein the low-reflectivity metal comprises titanium, tungsten, vanadium, or tantalum.

14. The method of claim 12, wherein the low-reflectivity metal has a low absorption coefficient.

15. The method of claim 12, wherein the low-reflectivity metal has a reflectivity below about 0.6 for wavelengths of light from about 0.4 micrometers to about 0.7 micrometers.

16. The method of claim 12, wherein the low-reflectivity metal has a k value below about 3.5 for wavelengths of light from about 0.2 micrometers to about 0.8 micrometers.

17. The method of claim 12, wherein the low-reflectivity metal forms an ionic compound when reacted with an element in a headspace of the digital micro-mirror device.

18. The method of claim 12, wherein the low-reflectivity metal forms a compound having a low partial pressure when reacted with an element in a headspace of the digital micro-mirror device.

19. The method of claim 12, wherein the low-reflectivity metal comprises a multilayer stack structure.

20. The method of claim 19, wherein the low-reflectivity metal is at least partially transmissive.

21. A method of forming a digital micro-mirror device structure, comprising the steps of:

forming circuitry elements at a substrate;

forming a conductive layer at selected locations of a surface of the substrate, the conductive layer comprising electrodes coupled to circuitry elements;

depositing a first layer of low-reflectivity metal over a surface of the conductive layer; and

forming a tiltable mirror structure disposed over the conductive layer and first layer of low-reflectivity metal.

22. The method of claim 21, wherein the low-reflectivity metal is selected from a group consisting of titanium, tungsten, vanadium, and tantalum.

23. The method of claim 21, further comprising:

depositing a second layer of low-reflectivity metal disposed over the first layer of low-reflectivity metal.

24. The method of claim 23, wherein each of the first and second layers of low-reflectivity metal are partially transmissive.

25. The method of claim 23, wherein the low-reflectivity metal has a low absorption coefficient.

26. The method of claim 21, wherein a fluorine compound of the low-reflectivity metal is an ionic compound.

27. The method of claim 26, wherein the fluorine compound of the low-reflectivity metal exhibits a relatively low partial pressure.

28. The method of claim 21, wherein the low-reflectivity metal has a reflectivity below about 0.6 for wavelengths of light from about 0.4 micrometers to about 0.7 micrometers.

29. The method of claim 21, wherein the low-reflectivity metal has a k value below about 3.5 for wavelengths of light from about 0.2 micrometers to about 0.8 micrometers.