Thin film actuated mirror array in an optical projection system and method for manufacturing the same

• US 5,886,811 A
• Filed: 09/30/1997
• Issued: 03/23/1999
• Est. Priority Date: 02/27/1997
• Status: Expired due to Fees

• Current Assignee: Dongbu Daewoo Electronics Corporation
• Original Assignee: Daewoo Electronics (Government of South Korea)
• Inventors: Min, Yong-Ki
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): BURKE, MARGARET A
• Application Number:
  US08/941,190
• Time in Patent Office: 539 Days
• Field of Search: 359/212, 359/224, 359/290, 359/291, 359/295, 359/318, 359/850, 359/855, 359/846
• US Class Current: 359/291
• 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

Thin film AMA has a substrate having electrical wiring and a connecting terminal, an actuator formed on the substrate, a supporting element formed between the substrate and the actuator for supporting the actuator, a reflecting member formed on the actuator, and a plurality of posts formed between the actuator and the reflecting member for supporting the reflecting member. The reflecting member is supported by a first post formed on the actuator and by a second post and a third post correspondingly formed on an actuator adjacent to the actuator. So, a deflection or tilting downward of the reflecting member can be prevented so that tilting angle of the reflecting members can be made uniform. Further, as the length of the reflecting member between the first post and the second post, or between the first post and the third post is shorter, the tilting angle of the reflecting member is bigger.

Claims

1. A thin film actuated mirror array in an optical projection system being actuated by a first signal and a second signal, said thin film actuated mirror array comprising:

a substrate having electrical wiring and a connecting terminal for receiving the first signal from outside and transmitting the first signal;

a supporting element having a supporting member formed on said substrate where said connecting terminal is formed and a first supporting layer, said first supporting layer having a first portion attached to said supporting member and a second portion formed parallel to said substrate;

an actuator having a bottom electrode formed on said first supporting layer for receiving the first signal, a top electrode corresponding to said bottom electrode for receiving the second signal and generating an electric field between said top electrode and said bottom electrode, and an active layer formed between said top electrode and said bottom electrode and deformed by the electric field;

a first post formed on a first portion of said actuator;

a second post and a third post formed on an actuator adjacent to said actuator where said supporting member is formed, said second post and said third post being formed corresponding to each other; and

a reflecting means for reflecting a light, said reflecting means being supported by said first post, said second post and said third post.

2. The thin film actuated mirror array in an optical projection system as claimed in claim 1, wherein said actuator has a `U` shape, said first post is formed in the middle of the first portion of said actuator, and said second post and said third post are correspondingly formed on both ends of said adjacent actuator having a `U` shape.

3. The thin film actuated mirror array in an optical projection system as claimed in claim 1, wherein said first post, said second post and said third post are respectively formed by using an elastic material.

4. The thin film actuated mirror array in an optical projection system as claimed in claim 1, wherein said first post is formed in the middle of the first portion of said actuator and said second post and said third post are correspondingly formed each other on both ends of said adjacent actuator, in such a manner that said first post, said second post and said third post are respectively located on the apexes of a triangle.

5. The thin film actuated mirror array in an optical projection system as claimed in claim 1, wherein a cross-sectional view of said first post, said second post and said reflecting means has an `F` shape and a cross-sectional view of said first post, said third post and said reflecting means has an `F` shape.

6. The thin film actuated mirror array in an optical projection system as claimed in claim 1, wherein the length of said reflecting means between said first post and said second post is shorter than that of said reflecting means between said first post and an end of said reflecting means, and the length of said reflecting means between said first post and said third post is shorter than that of said reflecting means between said first post and an end of said reflecting means.

7. The thin film actuated mirror array in an optical projection system as claimed in claim 1, wherein said reflecting means has a second supporting layer supported by said first post, said second post and said third post, and has a reflecting layer formed on said second supporting layer for reflecting a light, said second supporting layer enhancing a flatness of said reflecting means.

8. A thin film actuated mirror array in an optical projection system being actuated by a first signal and a second signal, said thin film actuated mirror array comprising:

a substrate having electrical wiring and a connecting terminal for receiving the first signal from outside and transmitting the first signal;

a supporting element having a supporting member formed on said substrate where said connecting terminal is formed and a first supporting layer, said first supporting layer having a first portion attached to said supporting member and a second portion formed parallel to said substrate;

an actuator having a bottom electrode formed on said first supporting layer for receiving the first signal, a top electrode corresponding to said bottom electrode for receiving the second signal and generating an electric field between said top electrode and said bottom electrode, and an active layer formed between said top electrode and said bottom electrode and deformed by the electric field, said actuator having a `U` shape;

a first post formed in the middle of a first portion of said actuator;

a second post and a third post correspondingly formed on both ends of said adjacent actuator having a `U` shape; and

a reflecting means for reflecting a light, said reflecting means being supported by said first post, said second post and said third post.

9. The thin film actuated mirror array in an optical projection system as claimed in claim 8, wherein said first post, said second post and said third post are respectively formed by using an elastic material, and said first post, said second post and said third post are respectively located on the apexes of a triangle.

10. The thin film actuated mirror array in an optical projection system as claimed in claim 8, wherein a cross-sectional view of said first post, said second post and said reflecting means has an `F` shape and a cross-sectional view of said first post, said third post and said reflecting means has an `F` shape.

11. The thin film actuated mirror array in an optical projection system as claimed in claim 8, wherein the length of said reflecting means between said first post and said second post is shorter than that of said reflecting means between said first post and an end of said reflecting means, and the length of said reflecting means between said first post and said third post is shorter than that of said reflecting means between said first post and an end of said reflecting means.

12. A thin film actuated mirror array in an optical projection system being actuated by a first signal and a second signal, said thin film actuated mirror array comprising:

a substrate having electrical wiring and a connecting terminal for receiving the first signal from outside and transmitting the first signal;

a supporting element having a supporting member formed on said substrate where said connecting terminal is formed and a first supporting layer, said first supporting layer having a first portion attached to said supporting member and a second portion formed parallel to said substrate;

an actuator having a bottom electrode formed on said first supporting layer for receiving the first signal, a top electrode corresponding to said bottom electrode for receiving the second signal and generating an electric field between said top electrode and said bottom electrode, and an active layer formed between said top electrode and said bottom electrode and deformed by the electric field;

a first post and a second post correspondingly formed on a first portion of said actuator;

a third post and a fourth post formed on an actuator adjacent to said actuator where said supporting member is formed, said third post and said fourth post being formed corresponding to each other; and

a reflecting means for reflecting a light, said reflecting means being supported by said first post, said second post, said third post and said fourth post.

13. The thin film actuated mirror array in an optical projection system as claimed in claim 12, wherein said actuator has a `U` shape, said first post and said second post are correspondingly formed on the first portion of said actuator, and said third post and said fourth post are correspondingly formed on both ends of said adjacent actuator having a `U` shape.

14. The thin film actuated mirror array in an optical projection system as claimed in claim 12, wherein said first post, said second post, said third post and said fourth post are respectively formed by using an elastic material, and said first post, said second post, said third post and said fourth post are respectively located on the apexes of a tetragon.

15. The thin film actuated mirror array in an optical projection system as claimed in claim 12, wherein the length of said reflecting means between said first post and said third post is shorter than that of said reflecting means between said first post and an end of said reflecting means, and the length of said reflecting means between said second post and said fourth post is shorter than that of said reflecting means between said second post and an end of said reflecting means.

16. A method for manufacturing a thin film actuated mirror array in an optical projection system being actuated by a first signal and a second signal, said method comprising the steps of:

providing a substrate having electrical wiring and a connecting terminal for receiving the first signal from outside and transmitting the first signal;

forming a first sacrificial layer on said substrate and patterning said first sacrificial layer to expose a portion of said substrate where said connecting terminal is formed;

forming a first layer on said exposed substrate and on said first sacrificial layer;

forming a bottom electrode layer, a second layer and a top electrode layer successively on said first layer;

forming an actuator by patterning said top electrode layer to form a top electrode for receiving the second signal and generating an electric field, by patterning said second layer to form an active layer deformed by the electric field, and by patterning said bottom electrode layer to form a bottom electrode for receiving the first signal;

forming a supporting element by patterning said first layer to form a first supporting layer beneath said bottom electrode, and by forming a supporting member under a first portion of said first supporting layer;

forming a second sacrificial layer on said actuator and on an actuator adjacent to said actuator and patterning said second sacrificial layer to expose a first portion of said actuator and to expose portions of said adjacent actuator correspondingly where said supporting member is formed;

forming a first post in the exposed first portion of said actuator;

forming a second post and a third post in the exposed portions of said adjacent actuator; and

forming a reflecting means on said first post, said second post, said third post and said second sacrificial layer for reflecting a light.

17. The method for manufacturing the thin film actuated mirror array in an optical projection system as claimed in claim 16, wherein the step of forming said first post and the step of forming said second post and said third post are concurrently performed.

18. The method for manufacturing the thin film actuated mirror array in an optical projection system as claimed in claim 16, wherein the step of forming said reflecting means further comprises the step of forming a second supporting layer on said first post, said second post, said third post and said second sacrificial layer, forming a reflecting layer on said second supporting layer, patterning said reflecting layer and said second supporting layer, and removing said second sacrificial layer.

19. The method for manufacturing the thin film actuated mirror array in an optical projection system as claimed in claim 18, wherein the step of forming said second supporting layer is performed by using nitride or metal and by a sputtering method or a chemical vapor deposition method.

20. The method for manufacturing the thin film actuated mirror array in an optical projection system as claimed in claim 18, wherein the step of removing said second sacrificial layer is performed by an oxygen plasma method.