Micro mirror unit, optical disc drive using same, and method for producing micro mirror unit

• US 20010017726A1
• Filed: 12/27/2000
• Published: 08/30/2001
• Est. Priority Date: 12/28/1999
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hori, Kazuhito, Kojima, Naoto, Hara, Masaki, Ido, Hiroto, Hane, Kazuhiro
• Granted Patent: US 6,914,871 B2
• Time in Patent Office: Days
• US Class Current: 359/223
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2201/11 Read heads, write heads or micropositioners for hard- or optical disks
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81C 1/00595 Control etch selectivity
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors
• CPC Class Codes: G11B 7/08564 using galvanomirrors
• CPC Class Codes: G11B 7/08576 Swinging-arm positioners
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

The hinge (13) should preferably be formed to have a higher resistance than ever against the pivoting of the mirror body (12) to effectively prevent the hinge (13) from being damaged. By adopting a suitable one of a variety of production steps as necessary, the hinge (13) can be formed more finely and with a higher precision and thus the micro mirror unit can be produced more easily in a shorter time. To this end, the hinge (13) is formed from a different material, such as SiN_x, from the mirror substrate material from which the frame (11) and mirror body (12) are formed.

Claims

1. A micro mirror unit including a frame and a mirror substrate, formed from a single substrate material, the mirror body having a mirror surface thereof formed on the mirror substrate being linked to the frame by means of hinges in such a manner that the mirror body is supported movably in relation to the frame,

the hinges of the micro mirror unit being formed from a different material from that from which the frame and mirror body are formed.

2. The apparatus as set forth in

claim 1

, wherein the hinges are formed from SiN_x.

3. The apparatus as set forth in

claim 2

, wherein the hinges are formed from a composite material of SiN_x having a metallic material laminated thereon.

4. The apparatus as set forth in

claim 1

, wherein the hinges are formed from SiO₂.

5. The apparatus as set forth in

claim 4

, wherein the hinges are formed from a composite material of SiO₂ having a metallic material laminated thereon.

6. The apparatus as set forth in

claim 1

, wherein the hinges are formed from SiC.

7. The apparatus as set forth in

claim 6

, wherein the hinges are formed from a composite material of SiC having a metallic material laminated thereon.

8. An optical disc drive in which a light is directed from a light source to an optical disc to thereby write and/or read information to and/or from the optical disc, comprising:

a micro mirror unit to reflect an incident light from the light source towards the optical disc;

the micro mirror unit including a frame and a mirror substrate, formed from a single substrate material;

a mirror body consisting of the mirror substrate and a mirror surface formed on the substrate being linked to the frame by means of hinges formed from a different material from that of the frame and mirror substrate, and thus supported movably in relation to the frame; and

the position of the light incident upon the optical disc being changed by moving the mirror body.

9. The optical disc drive as set forth in

claim 8

, wherein the micro mirror unit is provided on a floating slider which is levitated over the optical disc.

10. A method for producing a micro mirror unit comprising a frame and a mirror substrate, formed from a single substrate material, the mirror body having a mirror surface thereof formed on the mirror substrate being linked to the frame by means of hinges in such a manner that the mirror body is supported movably in relation to the frame, comprising:

a first step at which a material for the hinges are formed as layer on one main side of a substrate material for the frame and mirror substrate;

a second step at which a resist layer is formed on the other main side of the substrate material on which a mirror surface is formed; and

a third step at which the frame and mirror substrate are separated from each other by the dry etching using the resist layer as a mask.

11. The method as set forth in

claim 10

, wherein a material different in selection ratio to etching from the substrate material is used as a material for the hinge formed as a layer on the one main side of the substrate material at the first step;

and

the material for the hinges are dry-etched as an etching stopper at the third step.

12. The method as set forth in

claim 10

, wherein a material for the hinge different in selection ratio to etching from the substrate material is formed as a layer on the one main side of the substrate material at the first step;

and

a material different in selection ratio to etching from the substrate material is dry-etched as an etching stopper at the third step.

13. The method as set forth in

claim 10

, wherein the plasma CVD process is used to form the material for the hinge as a layer at the first step.

14. The method as set forth in

claim 10

, wherein the dry etching is effected by supplying SF₆ gas and CF₄ gas alternately as etching gases at the third step.