Thin film actuated mirror array

• US 5,636,070 A
• Filed: 04/28/1995
• Issued: 06/03/1997
• Est. Priority Date: 04/30/1994
• Status: Expired due to Term

• Current Assignee: Dongbu Daewoo Electronics Corporation (Dayou Holdings Co.,Ltd.)
• Original Assignee: Daewoo Electronics Company Limited (Dayou Holdings Co.,Ltd.)
• Inventors: Kim, Dong-Kuk, Ji, Jeong-Beom
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): Shin, Eunja
• Application Number:
  US08/430,628
• Time in Patent Office: 767 Days
• Field of Search: 310/328, 310/366, 29/25.35, 359/224, 359/225, 359/291, 359/295, 359/855, 359/900, 359/290, 359/297
• US Class Current: 359/855
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: H04R 17/08 signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously
• CPC Class Codes: Y10S 359/904 Micromirror
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A method for forming an array of M×N thin film actuated mirrors for use in an optical projection system comprises the steps of: (a) forming a sacrificial layer on top of an active matrix; (b) forming an array of M×N supporting members on the sacrificial layer; (c) depositing an elastic layer; (d) forming M×N conduits; (e) depositing a second thin film layer; (f) forming an electrodisplacive layer; (g) patterning the elastic layer, the second layer and the electrodisplacive layer to form an array of M×N semifinished actuated mirror structures; (h) heat treating the array of M×N semifinished actuated mirror structures; (i) depositing a first thin film layer on each of the semifinished actuated mirror structures to form an array of M×N actuated mirror structures; (j) covering each of the actuated mirror structures with a protection layer; and (k) removing the protection layer and the sacrificial layer to thereby form said array of M×N thin film actuated mirrors.

Claims

1. A method for manufacturing an array of M×

N thin film actuated mirrors, wherein M and N are integers, said method comprising the steps of;

(a) providing an active matrix having a top surface, the active matrix including a substrate, an array of M×

N pairs of connecting terminals on the top surface thereof;

(b) forming a sacrificial layer on the top surface of the active matrix in such a way that the sacrificial layer completely covers the array of M×

N pairs of connecting terminals;

(c) removing portions of the sacrificial layer surrounding each pair of the connecting terminals;

(d) forming a supporting member around each of connecting terminals by filling the portions with an insulating material;

(e) depositing an elastic layer, made of an insulating material, on top of the sacrificial layer including the supporting members;

(f) forming a conduit in each of the supporting members, each of the conduits extending from top of the elastic layer to each of the connecting terminals;

(g) depositing a second thin film layer made of an electrically conducting material on top of the elastic layer;

(h) forming an electrodisplacive layer on top of the second thin film layer to thereby form a semifinished actuating structure;

(i) patterning the elastic layer, the second layer and the electrodisplacive layer of the semifinished actuating structure until the sacrificial layer is exposed to thereby form an array of M×

N semifinished actuated mirror structures, wherein each of the semifinished actuated mirror structures includes an electrodisplacive layer, a second electrode layer and an elastic member;

(j) heat treating the array of M×

N semifinished actuated mirror structures to thereby force a phase transition to take place in the electrodisplacive layer in each of the semifinished actuated mirror structures;

(k) depositing a first thin film layer made of an electrically conducting and light reflecting material on each of the semifinished actuated mirror structures to form an array of M×

N actuated mirror structures, wherein each of the actuated mirror structures includes a top and four side surfaces;

(l) covering completely each of the actuated mirror structures with a thin film protection layer to thereby form an array of M×

N protected actuated mirror structures; and

(m) removing the thin film protection layer on the four side surfaces in each of the protected actuated mirror structures and the sacrificial layer to thereby form said array of M×

N thin film actuated mirrors.

2. The method of claim 1, wherein the sacrificial layer is formed by using a sputtering method if the sacrificial layer is made of a metal, a chemical vapor deposition method if the sacrificial layer is made of a phosphor-silicate glass, or a spin coating method if the sacrificial layer is made of a poli-Si.

3. The method of claim 1, wherein the second thin film layer is formed by using a sputtering method.

4. The method of claim 1, wherein the thin film electrodisplacive layer is formed by using a sol-gel method or a sputtering method.

5. The method of claim 1, where the first thin film layer is formed by using a sputtering method or a vacuum evaporation method.

6. The method of claim 1, wherein the semifinished actuating structure is patterned using a photolithography method or a laser trimming method.

7. The method of claim 1, wherein the sacrificial layer is removed by an etching method.

8. An optical projection system comprising an array of M×

N thin film actuated mirrors prepared in accordance with the method recited in any one of claims 1 to 7.