Electrostatic actuator and camera module using the same

• US 6,611,079 B2
• Filed: 10/31/2001
• Issued: 08/26/2003
• Est. Priority Date: 10/31/2000
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kasahara, Akihiro, Koga, Akihiro, Yoshida, Mitsunobu, Hattori, Shunsuke
• Primary Examiner(s): TAMAI, KARL I
• Application Number:
  US09/984,686
• Publication Number:
  US 20020050764A1
• Time in Patent Office: 664 Days
• Field of Search: 315/116, 310/309, 310/12, 348/374, 396/75, 396/661, 396/133, 396/439, 359/823, 359/834
• US Class Current: 310/309
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: H02N 1/004 in which a body is moved along a path due to interaction with an electric field travelling along the path

Abstract

An electrostatic actuator comprises first and second stator sections having a first electrode array arranged in a first direction, and a second electrode array of electrodes extending in the first direction, respectively. A movable section having fifth and sixth electrodes arranged to face the first and second electrode arrays, respectively, is arranged between the first and second stator sections. A driving circuit alternately performs a first driving operation in which a DC voltage is applied between the adjacent electrodes of the first electrode array and a second driving operation in which a DC voltage is applied between the electrodes of the second electrode array. The voltage application is successively performed by deviating the positions of the electrodes to which the voltage is applied so as to move the movable section in the first direction while vibrating the movable section between the first and second stator sections.

Claims

1. An electrostatic actuator, comprising:

a first stator section including a first electrode array including first, second, and third electrodes arranged at a predetermined pitch in a first direction;

a second stator section arranged to face the first stator section and to define a space between the first and second stator sections, and including a second electrode array including fourth and fifth electrodes;

a movable section arranged in the space and including a first electrode section facing the first electrode array and a second electrode section facing the second electrode array, the first and second electrode sections being maintained at a predetermined floating potential; and

a driving circuit configured to apply at least first, second, third and fourth DC voltage signals to the first and second electrode arrays, alternatively, each DC voltage signal having a first level higher than the predetermined floating potential and a second level lower than the predetermined potential,

the first DC voltage signal being applied to the adjacent first and second electrodes of the first electrode array to attract the first electrode section of the movable section during a first period, the first and second electrodes of the first electrode array being maintained at the first and second levels during the first period, respectively,

the second DC voltage signal being applied to the fourth and fifth electrodes of the second electrode array to attract the second electrode section of the movable section during a second period, the fourth electrode of the second electrode array being maintained at one of the first and second levels during the second period, and the fifth electrode of the second electrode array being maintained at the other of first and second levels during the second period, respectively,

the third DC voltage signal being applied to the adjacent second and third electrodes of the first electrode array to attract the first electrode section of the movable section during a third period, the second and third electrodes of the first electrode array being maintained at the first and second levels during the third period, respectively,

the fourth DC voltage signal being applied to the fourth and fifth electrodes of the second electrode array to attract the second electrode section of the movable section during a fourth period, the fourth electrode of the second electrode array being maintained at one of the first and second levels during the fourth period, and the fifth electrode of the second electrode array being maintained at the other of first and second levels during the fourth period, and

the movable section being moved in the first direction in accordance with the application of the first, second, third, and fourth DC voltage signals.

2. The electrostatic actuator according to claim 1, wherein:

the first electrode array further includes sixth electrodes, and

the driving circuit applies a fifth DC voltage signal to the adjacent third and sixth electrodes of the first electrode array to attract the first electrode section of the movable section during a fifth period, the third and sixth electrodes of the first electrode array being maintained at the first and second levels during the fifth period, respectively.

3. The electrostatic actuator according to claim 2, wherein:

the fourth and fifth electrodes of the second electrode array are extended in the first direction.

4. The electrostatic actuator according to claim 1, wherein:

the movable section has concave and convex portions faced to the first electrode array, the first electrode section of the movable section formed on the convex portion.

5. The electrostatic actuator according to claim 1, wherein:

the fourth and fifth electrodes of the second electrode array are extended in the first direction.

6. An electrostatic actuator, comprising:

a first stator section including a first electrode array including first, second, and third electrodes arranged at a predetermined pitch in a first direction;

a second stator section arranged to face the first stator section and to define a space between the first and second stator sections, and including a second electrode array including fourth, fifth, and sixth electrodes arranged at the predetermined pitch in the first direction;

a movable section arranged in the space and including a first electrode section facing the first electrode array and a second electrode section facing the second electrode array, the first and second electrode sections being maintained at a predetermined potential; and

a driving circuit configured to apply at least first, second, third, and fourth DC voltage signals to the first and second electrode arrays, alternatively, each DC voltage signal having a first level higher than the predetermined potential and a second level lower than the predetermined potential,

the first DC voltage signal being applied to the adjacent first and second electrodes of the first electrode array to attract the first electrode section of the movable section during a first period, the first and second electrodes of the first electrode array being maintained at the first and second levels during the first period, respectively,

the second DC voltage signal being applied to the adjacent fourth and fifth electrodes of the second electrode array to attract the second electrode section of the movable section during a second period, the fourth and fifth electrodes of the second electrode array being maintained at the first and second levels during the second period, respectively,

the third DC voltage signal being applied to the adjacent second and third electrodes of the first electrode array to attract the first electrode section of the movable section during a third period, the second and third electrodes of the first electrode array being maintained at the first and second levels during the third period, respectively,

the fourth DC voltage signal being applied to the adjacent fifth and sixth electrodes of the second electrode array to attract the second electrode of the movable section during a fourth period, the fifth and sixth electrodes of the second electrode array being maintained at the first and second levels during the fourth period, respectively, and

the movable section being moved in the first direction in accordance with the application of the first, second, third, and fourth DC voltage signals.

7. The electrostatic actuator according to claim 6, wherein:

the second electrode array is arranged at the same pitch as that of the first electrode array in the first direction and the arrangement of the second electrode array is deviated by half the predetermined pitch from the arrangement of the first electrode array.

8. The electrostatic actuator according to claim 6, wherein:

the first electrode array further includes a seventh electrode,

the second electrode array further includes an eighth electrode,

the driving circuit applies a fifth DC voltage signal to the adjacent third and seventh electrodes of the first electrode array to attract the first electrode section of the movable section during a fifth period, the third and seventh electrodes of the first electrode array being maintained at the first and second levels during the fifth period, respectively and

the driving circuit applies a sixth DC voltage signal to the fourth and eighth electrodes of the second electrode array to attract the second electrode section of the movable section during a sixth period, the fourth and eighth electrodes of the second electrode array being maintained at the first and second levels during the sixth period, respectively.

9. The electrostatic actuator according to claim 8, wherein:

the second electrode array is arranged at the same pitch as that of the first electrode array in the first direction and the arrangement of the second electrode array is deviated by half the predetermined pitch from the arrangement of the first electrode array.

10. The electrostatic actuator according to claim 6, wherein:

the movable section has concave and convex portions faced to the first electrode array, the first electrode section of the movable section formed on the convex portion.

11. The electrostatic actuator according to claim 6, wherein:

the first electrode array further includes sixth electrodes,

the fourth DC voltage signal is applied to the fourth and fifth electrodes of the fourth electrode array to attract the second electrode section of the movable section during a fourth period, and

the driving circuit applies a fifth DC voltage signal to the adjacent third and sixth electrodes of the first, second, and third electrode arrays to attract the first electrode section of the movable section during a fifth period, the third and sixth electrodes of the first electrode array being maintained at the first and second levels during the fifth period, respectively.

12. The electrostatic actuator according to claim 11, wherein:

the fourth and fifth electrodes of the fourth electrode array are extended in the first direction.

13. An electrostatic actuator, comprising:

a first stator section including first and second electrode arrays each including first, second, and third electrodes and arranged substantially in parallel and at a predetermined pitch in a first direction;

a second stator section arranged to face the first stator section and to define a space between the first and second stator sections, and including a third electrode array including fourth and fifth electrodes;

a movable section arranged in the space and including a first electrode section facing the first electrode array and a second electrode section facing the second electrode array, the first and second electrode sections being maintained at a predetermined potential; and

a driving circuit configured to apply at least first, second, and third DC voltage signals to the first, second, and third electrode arrays, alternatively, each DC voltage signals having a first level higher than the predetermined potential and a second level lower than the predetermined potential,

the first DC voltage signal being applied to the first and second electrodes of the first and second electrode arrays to attract the first electrode section of the movable section during a first period, the first and second electrodes of the first and second electrode arrays being maintained at the first and second levels during the first period, respectively,

the second DC voltage being applied to the fourth and fifth electrodes of the third electrode array to attract the second electrode section of the movable section during a second period,

the third DC voltage signal being applied to the second and third electrodes of the first and second electrode arrays to attract the first electrode section of the movable section during a third period, the second and third electrodes of the first and second electrode arrays being maintained at the first and second levels during the third period, respectively, and

the movable section being moved in the first direction in accordance with the application of the first, second, and third DC voltage signals.

14. The electrostatic actuator according to claim 13, wherein:

the fourth and fifth electrodes of the third electrode array are extended in the first direction.

15. The electrostatic actuator according to claim 14, wherein:

the first and second electrode arrays further include sixth electrodes,

the driving circuit applies a fourth DC voltage signal to the fourth and fifth electrodes of the third electrode array to attract the second electrode section of the movable section during a fourth period, and

the driving circuit applies a fifth DC voltage signal to the third and sixth electrodes of the first and second electrode arrays to attract the second electrode section of the movable section during a fifth period, the third and sixth electrodes of the first and second electrode arrays being maintained at the first and second levels during the fifth period, respectively.

16. The electrostatic actuator according to claim 15, wherein:

the fourth and fifth electrodes of the third electrode array are extended in the first direction.

17. An electrostatic actuator, comprising:

a first stator section including first and second electrode arrays each including first and second electrodes and arranged substantially in parallel and at a predetermined pitch in a first direction;

a second stator section arranged to face the first stator section and to define a space between the first and second stator sections, and including third and fourth electrode arrays each including third and fourth electrodes and arranged substantially in parallel and at a predetermined pitch in the first direction, the third and fourth electrode array being arranged at the same pitch as that of the first and second electrode arrays in the first direction and the arrangement of the third and fourth electrode arrays being deviated by half of the predetermined pitch from the arrangement of the first and second electrode arrays;

a movable section arranged in the space and including a first electrode section facing the first and second electrode arrays and a second electrode section facing the third and fourth electrode arrays, the first and second electrode sections being maintained at a predetermined potential; and

a driving circuit configured to apply at least first, second, third, and fourth DC voltage signals to the first, second, third, and fourth electrode arrays, alternatively, each DC voltage signal having a first level higher than the predetermined potential and a second level lower than the predetermined potential,

the first DC voltage signal being applied to the first electrodes of the first and second electrode arrays to attract the first electrode section of the movable section during a first period, the first electrodes of the first and second electrode arrays being maintained at the first and second levels during the first period, respectively,

the second DC voltage signal being applied to the third electrodes of the third and fourth electrode arrays to attract the second electrode section of the movable section during a second period, the third electrodes of the third and fourth electrode arrays being maintained at the first and second levels during the second period, respectively,

the third DC voltage signal being applied to the second electrodes of the first and second electrode arrays to attract the first electrode section of the movable section during a third period, the second electrodes of the first and second electrode arrays being maintained at the first and second levels during the third period, respectively,

the fourth DC voltage signal being applied to the fourth electrodes of the third and fourth electrode arrays to attract the second electrode section of the movable section during a fourth period, the fourth electrodes of the third and fourth electrode arrays being maintained at the first and second levels during the fourth period, respectively, and

the movable section being moved in the first direction in accordance with the application of the first, second, third, and fourth DC voltage signals.

18. The electrostatic actuator according to claim 17, wherein:

the first and second electrode arrays further include a fifth electrode,

the third and fourth electrode arrays further include a sixth electrode,

the driving circuit applies a fifth DC voltage signal to the fifth electrodes of the first and second electrode arrays to attract the first electrode section of the movable section during a fifth period, the fifth electrodes of the first and second electrode arrays being maintained at the first and second levels during the fifth period, respectively, and

the driving circuit applies a sixth DC voltage signal to the sixth electrodes of the third and fourth electrode arrays to attract the second electrode section of the movable section during a sixth period, the sixth electrodes of the third and fourth electrode arrays being maintained at the first and second levels during the sixth period, respectively.

19. An electrostatic actuator, comprising:

a first stator section including first, second, and third electrode arrays each including first, second and third electrodes and arranged substantially in parallel and at a predetermined pitch in a first direction;

a second stator section arranged to face the first stator section and to define a space between the first and second stator sections, and including a fourth electrode array including fourth and fifth electrodes;

a movable section arranged in the space and including a first electrode section facing the first, second, and third electrode arrays and a second electrode section facing the fourth electrode array, the first and second electrode sections being maintained at a predetermined potential; and

a driving circuit configured to apply at least first, second, and third DC voltage signals to the first, second, third, and fourth electrode arrays, alternatively, each DC voltage signal having a first level higher than the predetermined potential and a second level lower than the predetermined potential,

the first DC voltage signal being applied to the first and second electrodes of the first, second, and third electrode arrays to attract the first electrode section of the movable section during a first period, the first and second electrodes of the first and third electrode arrays being maintained at one of the first and second levels during the first period and the first and second electrodes of the second electrode array being maintained at the other of the first and second levels during the first period,

the second DC voltage signal being applied to the fourth and fifth electrodes of the fourth electrode array to attract the second electrode section of the movable section during a second period,

the third DC voltage signal being applied to the second and third electrodes of the first, second, and third electrode arrays to attract the first electrode section of the movable section during a third period, the second and third electrodes of the first and third electrode arrays being maintained at one of the first and second levels during the third period, the second electrodes of the second electrode array being maintained at the other of the first and second levels during the third period, and

the movable section being moved in the first direction in accordance with the application of the first, second, and third DC voltage signals.

20. The electrostatic actuator according to claim 19, wherein:

the fourth and fifth electrodes of the fourth electrode array are extended in the first direction.

21. The electrostatic actuator according to claim 20, wherein:

the movable section has concave and convex portions faced to the first electrode array, the first electrode section of the movable section formed on the convex portion.