Micro-actuator with interdigitated combs perpendicular to a base

• US 6,781,279 B2
• Filed: 06/05/2001
• Issued: 08/24/2004
• Est. Priority Date: 08/18/2000
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ko, Young-Chul, Lee, Jin-Ho, Kong, Do-Hyun
• Primary Examiner(s): TAMAI, KARL I
• Application Number:
  US09/873,382
• Publication Number:
  US 20020021055A1
• Time in Patent Office: 1,176 Days
• Field of Search: 310/309, 359/223, 359/291, 359/872, 359/224, 385/18
• US Class Current: 310/309
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81B 2203/0181 See-saws
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81C 1/00142 Bridges deformable micromirrors G02B26/0841
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: B81C 2203/038 Bonding techniques not provided for in B81C2203/031 - B81C2203/037
• CPC Class Codes: B81C 3/001 Bonding of two components
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/435 Solid dielectric type

Abstract

A micro-actuator having a stage capable of a see-saw motion and a method for its manufacture are disclosed. In the micro-actuator according to the present invention, a plurality of parallel driving comb-type electrodes are formed on the bottom of the stage, and a plurality of parallel fixed comb-type electrodes are formed on a base plate. At both sides of the stage is a torsion bar that enables the see-saw motion. The torsion bar is supported by a frame comprised of a first frame layer and a second frame layer. The torsion bar and the first frame layer form one body. The first and second frame layers are bonded by a metal eutectic bonding layer between metal layers.

Claims

1. A micro-actuator comprising:

a base plate on which a predetermined pattern of signal lines is formed;

a plurality of fixed comb-type electrodes that are arranged on the base plate and extend in a direction perpendicular to the base plate;

a stage capable of a see-saw motion that is arranged at a predetermined height from the top of the base plate;

a plurality of driving comb-type electrodes which are formed parallel to each other on the bottom of the stage and whose ends extend between the fixed comb-type electrodes;

a torsion bar with a predetermined length and thickness that is arranged at both ends of the stage forming one body with the stage in order to enable the see-saw motion of the stage, wherein the thickness of the torsion bar is less than the plurality of driving comb-type electrodes in a direction parallel to the plurality of driving comb-type electrodes;

a first frame layer connected to both ends of the torsion bar;

a second frame layer that is positioned below the first frame layer, thus forming a layered structure with the first frame layer; and

a metal eutectic bonding layer formed between the first and second frame layers to bond them together, wherein

the fixed comb-type electrodes are formed on an electrode base that is arranged on the base plate, and

the electrode base, the fixed comb-type electrodes and the second frame layer are formed of the same material.

3. The micro-actuator of claim 1, wherein the height of the fixed comb-type electrodes is greater than that of the second frame layer, and thus the front ends of the fixed comb-type electrodes are positioned higher than the top of the second frame layer.

4. The micro-actuator of claim 3, wherein the front ends of the driving comb-type electrodes and the first frame layer are on a common plane.

5. A micro-actuator comprising:

a base plate on which a predetermined pattern of signal lines is formed;

a plurality of fixed comb-type electrodes that are arranged on the base plate and extend in a direction perpendicular to the base plate;

a stage capable of a see-saw motion that is arranged at a predetermined height from the top of the base plate;

a plurality of driving comb-type electrodes which are formed parallel to each other on the bottom of the stage and whose ends extend between the fixed comb-type electrodes;

a torsion bar with a predetermined length and thickness that is arranged at both ends of the stage forming one body with the stage in order to enable the see-saw motion of the stage, wherein the thickness of the torsion bar is less than the plurality of driving comb-type electrodes in a direction parallel to the plurality of driving comb-type electrodes;

a first frame layer connected to both ends of the torsion bar;

a second frame layer that is positioned below the first frame layer, thus forming a layered structure with the first frame layer; and

a metal eutectic bonding layer formed between the first and second frame layers to bond them together, wherein

the first frame layer, the torsion bar, the stage, and the driving comb-type electrodes form one body,

the fixed comb-type electrodes are formed on an electrode base that is arranged on the base plate, and

the electrode base, the fixed comb-type electrodes and the second frame layer are formed of the same material.

2. The micro-actuator of claim 5, wherein the front ends of the driving comb-type electrodes and the first frame layer are on a common plane.

6. A micro-actuator comprising:

a base plate on which a predetermined pattern of signal lines is formed;

a plurality of fixed comb-type electrodes that are arranged on the base plate and extend in a direction perpendicular to the base plate;

a stage capable of a see-saw motion that is arranged at a predetermined height from the top of the base plate;

a plurality of driving comb-type electrodes which are formed parallel to each other on the bottom of the stage and whose ends extend between the fixed comb-type electrodes;

a torsion bar with a predetermined length and thickness that is arranged at both ends of the stage forming one body with the stage in order to enable the see-saw motion of the stage, wherein the thickness of the torsion bar is less than the plurality of driving comb-type electrodes in a direction parallel to the plurality of driving comb-type electrodes;

a first frame layer connected to both ends of the torsion bar;

a second frame layer that is positioned below the first frame layer, thus forming a layered structure with the first frame layer; and

a metal eutectic bonding layer formed between the first and second frame layers to bond them together, wherein

the first frame layer has a shape of a rectangular border that surrounds the stage.

a separate region of a predetermined width is located between the first frame layer and the stage,

the torsion bar crosses the separate region,

the fixed comb-type electrodes are formed on an electrode base that is arranged on the base plate, and

the electrode base, the fixed comb-type electrodes and the second frame layer are formed of the same material.

7. A micro-actuator comprising:

a base plate on which a predetermined pattern of signal lines is formed;

a plurality of fixed comb-type electrodes that are arranged on the base plate and extend in a direction perpendicular to the base plate;

a stage capable of a see-saw motion that is arranged at a predetermined height from the top of the base plate;

a plurality of driving comb-type electrodes which are formed parallel to each other on the bottom of the stage and whose ends extend between the fixed comb-type electrodes;

a torsion bar with a predetermined length and thickness that is arranged at both ends of the stage forming one body with the stage in order to enable the see-saw motion of the stage, wherein the thickness of the torsion bar is less than the plurality of driving comb-type electrodes in a direction parallel to the plurality of driving comb-type electrodes;

a first frame layer connected to both ends of the torsion bar;

a second frame layer that is positioned below the first frame layer, thus forming a layered structure with the first frame layer; and

a metal eutectic bonding layer formed between the first and second frame layers to bond them together, wherein

the first frame layer has a shape of a rectangular border that surrounds the stage,

a separate region of a predetermined width having a shape of rectangular border is prepared between the first frame layer and the stage.

the torsion bar crosses the separate region.

the fixed comb-type electrodes are formed on an electrode base that is arranged on the base plate, and

the electrode base, the fixed comb-type electrodes and the second frame layer are formed of the same material.

8.The micro-actuator of claim 6, wherein the front ends of the driving comb-type electrodes and the first frame layer are on a common plane.