Control device, optical filter system, and control method

Patent metadata

Field	Value
Publication number	US-12259275-B2
Application number	US-201917294051-A
Country	US
Kind code	B2
Filing date	Sep 9, 2019
Priority date	Dec 18, 2018
Publication date	Mar 25, 2025
Grant date	Mar 25, 2025

Abstract

Provided is a control device for controlling a Fabry-Perot interference filter having a pair of mirror parts and a pair of driving electrodes. The control device includes: a first driving source that is controlled by using a current as a control parameter, and changes the distance between the pair of mirror parts; a second driving source that is controlled by using a voltage as a control parameter, and changes the distance; and a control unit that controls the first driving source and the second driving source in such a way that the distance is changed by a first driving source in a first region and the distance is changed by the second driving source in at least one part of an region other than the first region when an region including a maximum of the voltage is defined as the first region.

First claim

The invention claimed is:

1. A control device for controlling a Fabry-Perot interference filter having a pair of mirror parts facing each other with an air gap therebetween and a pair of driving electrodes facing each other with the air gap therebetween, and having a distance between the pair of mirror parts changed in accordance with charges stored between the pair of driving electrodes, the control device comprising:
a first driving source that is controlled by using a current as a control parameter, and changes the distance between the pair of mirror parts;
a second driving source that is controlled by using a voltage as a control parameter, and changes the distance between the pair of mirror parts; and
a control unit that controls the first driving source and the second driving source in such a way that the distance between the pair of mirror parts is changed by the first driving source without using the second driving source in a first region and the distance between the pair of mirror parts is changed by the second driving source without using the first driving source in at least a part of a region other than the first region when a region including a maximum of the voltage in relation between the charges stored between the pair of driving electrodes, and the voltage between the pair of driving electrodes is defined as the first region.

2. The control device according to claim 1 , wherein
the control unit controls the first driving source and the second driving source in such a way that the distance between the pair of mirror parts is changed by the second driving source in a second region when an region in which the charges are larger than the charges in the first region in the relation is defined as the second region.

3. The control device according to claim 2 , wherein
the second driving source has a first driving unit,
the first driving unit is configured in such a way that:
when a control voltage of the first driving unit is larger than the voltage generated between the pair of driving electrodes, the distance between the pair of mirror parts increases; and
when the control voltage of the first driving unit is smaller than the voltage generated between the pair of driving electrodes, the distance between the pair of mirror parts decreases, and

the control unit controls the first driving source and the second driving source in such a way that the distance between the pair of mirror parts is changed by the first driving unit in the second region.

4. The control device according to claim 3 , wherein
the first driving unit includes an operational amplifier, and
in the operational amplifier, a non-inverting input terminal is connected to an output terminal, the output terminal is connected to the Fabry-Perot interference filter, and the control voltage is applied to an inverting input terminal.

5. The control device according to claim 1 , wherein
the control unit controls the first driving source and the second driving source in such a way that the distance between the pair of mirror parts is changed by the second driving source in a third region when an region in which the charges are smaller than the charges in the first region in the relation is defined as the third region.

6. The control device according to claim 5 , wherein
the second driving source has a second driving unit,
the second driving unit is configured in such a way that:
when a control voltage of the second driving unit is larger than the voltage generated between the pair of mirror parts, the distance between the pair of mirror parts decreases; and
when the control voltage of the second driving unit is smaller than the voltage generated between the pair of mirror parts, the distance between the pair of mirror parts increases, and

the control unit controls the first driving source and the second driving source in such a way that the distance between the pair of mirror parts is changed by the second driving unit in the third region.

7. The control device according to claim 6 , wherein
the second driving unit includes an operational amplifier, and
in the operational amplifier, an inverting input terminal is connected to an output terminal, the output terminal is connected to the Fabry-Perot interference filter, and the control voltage is applied to a non-inverting input terminal.

8. The control device according to claim 1 , further comprising a voltage detection unit that detects the voltage generated between the pair of driving electrodes, wherein
when the distance between the pair of mirror parts is changed by the first driving source, the control unit feedback-controls the first driving source based on a detection result of the voltage detection unit.

9. The control device according to claim 8 , wherein
the control unit switches use states of the first driving source and the second driving source from a state in which the distance between the pair of mirror parts is changed by the first driving source to a state in which the distance between the pair of mirror parts is changed by the second driving source based on a detection result of the voltage detection unit.

10. The control device according to claim 1 , wherein
the control unit switches use states of the first driving source and the second driving source from a state in which the distance between the pair of mirror parts is changed by the second driving source to a state in which the distance between the pair of mirror parts is changed by the first driving source based on a control voltage of the second driving source.

11. The control device according to claim 1 , further comprising:
a current application unit that applies an alternating current having a frequency higher than a resonance frequency of the pair of mirror parts between the pair of driving electrodes; and
a voltage detection unit that detects a voltage generated between the pair of driving electrodes during application of the alternating current, wherein
the control unit calculates electrostatic capacity between the pair of driving electrodes based on a detection result of the voltage detection unit.

12. The control device according to claim 1 , wherein
the first driving source is capable of supplying and absorbing a current.

13. An optical filter system comprising:
the control device according to claim 1 ; and
the Fabry-Perot interference filter controlled by the control device.

14. A control method for controlling a Fabry-Perot interference filter having a pair of mirror parts facing each other with an air gap therebetween and a pair of driving electrodes facing each other with the air gap therebetween, and having a distance between the pair of mirror parts changed in accordance with charges stored between the pair of driving electrodes, the control method comprising:
changing the distance between the pair of mirror parts by a first driving source without using a second driving source in a first region and changing the distance between the pair of mirror parts by the second driving source without using the first driving source in at least a part of a region other than the first region when a region including a maximum of the voltage in relation between the charges stored between the pair of driving electrodes, and the voltage between the pair of driving electrodes is defined as the first region, by using:
the first driving source that is controlled by using a current as a control parameter, and changes the distance between the pair of mirror parts; and
the second driving source that is controlled by using a voltage as a control parameter, and changes the distance between the pair of mirror parts.

Assignees

• Hamamatsu Photonics Kk

Inventors

• Seitz Peter
• Teichmann Helmut
• Shibayama Katsumi
• Kasahara Takashi

Classifications

• G02B26/001

  based on interference in an adjustable optical cavity (interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26) · CPC title

• G02B5/284

  of etalon type comprising a resonant cavity other than a thin solid film, e.g. gas, air, solid plates (etalons for fibre optic multiplexing G02B6/29358; etalons for spectral measurement G01J3/26) · CPC title

• G02B26/0841

  the reflecting element being moved or deformed by electrostatic means · CPC title

• G02B1/11

  Anti-reflection coatings · CPC title

• G01J3/0264

  Electrical interface; User interface · CPC title