Package for micromirror device

• US 8,194,305 B2
• Filed: 09/05/2008
• Issued: 06/05/2012
• Est. Priority Date: 11/01/2003
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Maeda, Yoshihiro, Nishino, Hirokazu, Shirai, Akira, Ichikawa, Hirotoshi, Ishii, Fusao
• Primary Examiner(s): Martinez, Joseph P
• Assistant Examiner(s): Thomas, Brandi
• Application Number:
  US12/231,922
• Publication Number:
  US 20090008669A1
• Time in Patent Office: 1,369 Days
• Field of Search: 359290-292, 359/298
• US Class Current: 359/298
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]

Abstract

The present invention discloses a mirror device that includes a mirror element which further comprising an elastic hinge and a mirror and which modulates incident light emitted from a light source, a device substrate on which a drive circuit for driving the mirror element is placed, a package substrate which is made of transparent glass or a silicon material and on which the device substrate is placed, a metallic thermal transfer path connected to the device substrate, and a cover glass connected to the package substrate so that the device substrate is covered.

Claims

1. A mirror device, comprising:

a mirror element comprises an elastic hinge and a mirror to modulate an incident light emitted from a light source;

a device substrate supports a drive circuit for driving the mirror;

a package includes a package substrate, composed of a transparent glass or a silicon material for containing and supporting the device substrate thereon

the package further includes a cover glass disposed on top of the package substrate covering over the device substrate; and

a metallic thermal transfer path comprising a plurality of metal traces disposing on a top surface of the package substrate and extending from a central portion near the drive circuit of the mirror to a peripheral edge of the package substrate outside of the area covered under the cover glass.

2. The mirror device according to claim 1, wherein:

the package substrate or cover glass further comprising a cavity for placing the device substrate therein.

3. The mirror device according to claim 1, wherein:

at least a part of the metal traces of the thermal transfer path comprising patterned circuit wires connected to the device substrate.

4. The mirror device according to claim 1, wherein:

the package further comprises an open space adjacent to the bottom surface of the device substrate for radiating heat from the bottom surface of the device substrate to transfer heat through the thermal transfer path to outside of the package substrate.

5. The mirror device according to claim 1, wherein:

an area surface of the package substrate not covered by the cover glass and the surface areas of the cover glass are further covered by a light absorption layer for reducing a reflection from the package.

6. A mirror device comprising:

a mirror element comprises an elastic hinge and a mirror to modulate an incident light emitted from a light source;

a device substrate supports a drive circuit for driving the mirror substrate,

a package includes a package substrate composed of a transparent glass or a silicon material for containing and supporting the device substrate thereon

a metallic thermal transfer path connected to the device substrate;

the package further includes a cover glass disposed on top of the package substrate covering over the device substrate; and

a nano-structured anti-reflection coating layer with the reflectance no more than 0.4% of the incident light is formed on the cover glass and/or the package substrate.

7. A mirror device, comprising:

a mirror for modulating incident light emitted from a light source;

an elastic hinge for supporting the mirror on the bottom surface thereof;

a device substrate on which a drive circuit for driving the mirror is placed;

a thermal conduction member placed on the bottom surface of the device substrate;

a package substrate for supporting the device substrate; and

a cover glass joined, with a fitted glass or a low-melt metal, onto the package substrate so as to cover the device substrate, wherein the difference in linear expansion rates between the package substrate and cover glass is no more than 2*10<sup>−

6</sup>/K.

8. The mirror device according to claim 7, wherein:

the package substrate is constituted by a material with the thermal conductivity being no less than 40 Wm/K.

9. The mirror device according to claim 7, wherein:

the package substrate is constituted by approximately the same material as that of the device substrate.

10. The mirror device according to claim 7, wherein:

the package substrate and elastic hinge are constituted by a material containing silicon.

11. The mirror device according to claim 7, wherein:

the package substrate is constituted by a silicon material.

12. The mirror device according to claim 7, wherein:

the package substrate is constituted by a silicon nitride material.

13. The mirror device according to claim 7, wherein:

the package substrate is constituted by a silicon carbide material.

14. The mirror device according to claim 7, wherein:

the package substrate is constituted by a glass layer and a silicon layer.

15. The mirror device according to claim 7, wherein:

the glass transition temperature of the fritted glass is no higher than 350 degrees C. and the melting point of the low-melt metal is no higher than 350 degrees C.

16. A mirror device, comprising:

a mirror element comprises a mirror for modulating incident light emitted from a light source;

a device substrate supports a drive circuit for driving the mirror;

a package substrate for disposing the device substrate thereon, wherein the package substrate composed of silicon wafer comprising diced wafer edges and the device substrate comprising said driving circuit formed by processes performed on the device substrate as another silicon wafer; and

a metallic thermal transfer path comprising a plurality of metal traces disposing on a top surface of the package substrate and extending from a central portion near the drive circuit of the mirror to a peripheral area near the dice wafer edges of the package substrate away from an area under the device substrate.

17. The mirror device according to claim 16, wherein:

the silicon wafer comprising said diced wafer edges comprises a recycled silicon wafer.

18. The mirror device according to claim 16, wherein:

the silicon wafer to form the package substrate is substantially the same size as said another silicon wafer to form the device substrate.

19. The mirror device according to claim 16, wherein:

the metal traces further comprises circuit wires connected to the device substrate.