Switching apparatus and test apparatus
View Patent ↗To restrict a bowing amount of a piezoelectric actuator, provided is a switching apparatus comprising a contact point section including a first contact point; and an actuator that moves a second contact point to contact or move away from the first contact point. The actuator includes a first piezoelectric film that expands and contracts according to a drive voltage to change a bowing amount of the actuator, and a second piezoelectric film that is provided in parallel with the first piezoelectric film and restricts bowing of the actuator when the drive voltage is not being supplied to the first piezoelectric film.
1. A switching apparatus comprising:
a contact point section including a first contact point; and
an actuator that moves a second contact point to contact or move away from the first contact point, wherein
the actuator includes a first piezoelectric film that expands and contracts according to a drive voltage to change a bowing amount of the actuator, and a second piezoelectric film that is provided in parallel with the first piezoelectric film and restricts bowing of the actuator caused by stress of the first piezoelectric film in an initial state when the drive voltage is not being supplied to the first piezoelectric film.
2. The switching apparatus according to claim 1 , wherein
the second piezoelectric film restricts bowing of the actuator caused by expansion and contraction due to temperature change of the first piezoelectric film.
3. The switching apparatus according to claim 1 , wherein
the first piezoelectric film and the second piezoelectric film are provided on respective sides of a central plane in a thickness direction of the actuator.
4. The switching apparatus according to claim 3 , wherein
the first piezoelectric film and the second piezoelectric film have substantially the same thickness and are arranged at substantially the same distance from the central plane in the thickness direction of the actuator.
5. The switching apparatus according to claim 4 , wherein
the actuator includes a plurality of films layered substantially symmetrically with respect to the central plane in the thickness direction.
6. The switching apparatus according to claim 1 , wherein
the first piezoelectric film and the second piezoelectric film are PZT films.
7. The switching apparatus according to claim 1 , wherein
the actuator includes a first support layer disposed between the first piezoelectric film and the second piezoelectric film.
8. The switching apparatus according to claim 7 , wherein
the actuator further includes electrode layers respectively on a top surface and a bottom surface of each of the first piezoelectric film and the second piezoelectric film, the electrode layers applying respective drive voltages.
9. The switching apparatus according to claim 7 , wherein
the actuator is deposited using a semiconductor process.
10. The switching apparatus according to claim 9 , wherein
the first support layer is not damaged when heated to a firing temperature of the first piezoelectric film and the second piezoelectric film.
11. The switching apparatus according to claim 10 , wherein
the first support layer is an insulating layer.
12. The switching apparatus according to claim 11 , wherein
the first support layer includes SiO 2 or SiN.
13. The switching apparatus according to claim 11 , wherein
the insulating layer has an exposed portion, which is covered by neither the first piezoelectric film nor the second piezoelectric film, at a tip portion of the actuator.
14. The switching apparatus according to claim 13 , wherein
the second contact point is provided on the exposed portion.
15. A switching apparatus according comprising:
a contact point section including a first contact point; and
an actuator that moves a second contact point to contact or move away from the first contact point, wherein
the actuator includes:
a first piezoelectric film that expands and contracts according to a drive voltage to change a bowing amount of the actuator;
a second piezoelectric film that is provided in parallel with the first piezoelectric film and restricts bowing of the actuator when the drive voltage is not being supplied to the first piezoelectric film;
a first support layer disposed between the first piezoelectric film and the second piezoelectric film; and
a second support layer and a third support layer that are respectively disposed outward from the first piezoelectric film and the second piezoelectric film with respect to the central plane in the thickness direction of the actuator.
16. The switching apparatus according to claim 15 , wherein
the second support layer and the third support layer include SiO 2 or SiN.
17. A test apparatus that tests a device under test, comprising:
a testing section that tests the device under test by exchanging electrical signals with the device under test; and
the switching apparatus according to claim 1 that is provided between the testing section and the device under test and provides an electrical connection or disconnection between the testing section and the device under test.
18. The switching apparatus according to claim 10 , wherein
the first support layer is an insulating layer formed using a CVD.
19. The switching apparatus according to claim 1 , wherein
the second piezoelectric film is formed of substantially the same material as the first piezoelectric film and has substantially the same shape as the first piezoelectric film, and is formed on a surface of the actuator that is opposite to a surface on which the first piezoelectric is formed.