Light modulator

• US 20050275925A1
• Filed: 05/27/2004
• Published: 12/15/2005
• Est. Priority Date: 05/27/2004
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Chen, Chien-Hua, Craig, David M.
• Granted Patent: US 7,019,886 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B

Abstract

A method for forming a light modulator includes supporting a plurality of optical devices on a substrate, and attaching a sheet of glass over the optical devices. The method also includes slicing the sheet of glass into a plurality of pieces of glass.

Claims

1. A package comprising:

a light modulator supported on a substrate, the light modulator including;

an optical device supported on the substrate;

a casing attached to the substrate, the casing surrounding the optical device, the casing further including sidewalls having stress relief structures therein; and

a glass lid attached to the casing, the glass lid, casing and substrate substantially sealing the optical device.

2. The package of claim 1 further comprising a desiccant positioned within a volume sealed by the casing, glass lid and the substrate.

3. The package of claim 1 wherein the optical device is a MEMS device.

4. The package of claim 1 wherein the light modulator is fabricated on the substrate.

5. The package of claim 1 wherein the glass lid is tilted with respect to the substrate.

6. The package of claim 1 wherein the casing includes Kovar.

7. The package of claim 1 wherein the casing includes 54Fe-29Ni-17Co.

8. The package of claim 1 wherein the casing is comprised of a metal material having a coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of silicon.

9. The package of claim 1 further comprising adhesive attached to the sidewalls of the casing.

10. The package of claim 1 further comprising a first solder material for attaching the casing to the substrate and a second solder material for attaching the frame to the glass lid.

11. The package of claim 10 wherein the first solder material for attaching the casing to the substrate has a higher melting point than the second solder material for attaching the frame to the glass lid.

12. A substrate comprising:

a first major surface;

a second major surface;

a plurality of optical devices supported on the first major surface;

a metal sheet including a plurality of connected casings, each casing including an aperture, the casing further including sidewalls surrounding the apertures, the metal sheet supported on the first major surface so that the sidewalls of at least two of said plurality of casings surround at least two of the optical devices attached to the first major surface.

13. The substrate of claim 12 wherein the sidewalls surrounding the apertures include a stress relief structure.

14. The substrate of claim 12 wherein the portion of the metal sheet proximate the aperture is spaced from the substrate.

15. The substrate of claim 14 wherein the metal sheet further includes a bridge positioned between at least a first sidewall associated with a first aperture and a second sidewall associated with a second aperture, the bridge spanning at least one electrical contact on the substrate.

16. The substrate of claim 14 further comprising a sheet of glass attached to the portions of the metal sheet proximate the plurality of apertures, the glass sheet spanning at least two of the apertures in the metal sheet.

17. The substrate of claim 16 wherein the sheet of glass has a cut therein between the first sidewall associated with the first aperture and the second sidewall associated with the second aperture.

18. The substrate of claim 14 wherein the substrate further includes a slice separating a first optical device from a second optical device.

19. The substrate of claim 12 wherein the sheet of metal is formed of a material having a coefficient of thermal expansion substantially the same as the coefficient of thermal expansion of the wafer.

20. The substrate of claim 12 wherein the optical devices are MEMS devices.

21. A method for forming a plurality of light modulators comprising:

supporting a plurality of optical devices on a substrate; and

placing a sheet of glass over the optical devices;

slicing the sheet of glass into a plurality of pieces of glass, wherein at least two of the pieces of glass are associated with at least two of the plurality of optical devices supported on the substrate.

22. The method of claim 21 further comprising slicing the substrate to separate at least two of the plurality of light modulators, each light modulator including at least one optical device.

23. The method of claim 21 further comprising tilting the glass attached to the substrate and positioned over at least two of the optical devices.

24. The method of claim 23 further comprising setting the tilt of the glass for at least two of the optical devices.

25. The method of claim 23 wherein placing a sheet of glass over the optical devices further comprises:

attaching a casing sheet that includes a plurality of casings to the substrate, the casing sheet having apertures therein and wherein at least two of the apertures correspond to at least two of the optical devices; and

attaching the sheet of glass to the casing sheet.

26. The method of claim 25 wherein each of the casings associated with the casing sheet includes a set of sidewalls having a stress relief feature therein, and wherein tilting the glass includes shortening or lengthening a portion of at least one of the sidewalls at the stress relief feature.

27. The method of claim 26 further comprising setting the tilt of the glass for at least two of the optical devices by placing an adhesive on at least one of the stress relief features of the sidewalls of at least two of the casings.

28. The method of claim 25 wherein attaching the casing sheet includes bridging an electrical contact associated with one of the plurality of optical devices and bridging an electrical contact associated with another of the plurality of optical devices.

29. The method of claim 28 further comprising slicing the bridge between at least two of the casings associated with the casing sheet.

30. The method of claim 25 wherein attaching the casing sheet to the substrate includes soldering the attachment using a first solder and wherein attaching the glass to the casing uses a second solder, wherein the first solder has a higher melting point than the first solder.

31. A light modulator comprising:

a substrate;

an optical device supported on the substrate; and

means for supporting and tilting glass positioned proximate the optical device.

32. The light modulator of claim 31 further comprising:

means for setting the tilt of the glass.