JP5888080B2 - Wavelength variable interference filter, optical filter device, optical module, electronic apparatus, and wavelength variable interference filter driving method - Google Patents

Description

  The present invention relates to a wavelength tunable interference filter, an optical filter device, an optical module, an electronic apparatus, and a driving method of the wavelength tunable interference filter.

  Conventionally, in a Fabry-Perot interferometer (Fabry-Perot etalon) that extracts light of a predetermined target wavelength by two reflective films facing each other, a wavelength that changes the wavelength of light to be extracted by changing the gap dimension between the two reflective films. A variable interference filter is known (see, for example, Patent Document 1).

In the wavelength variable interference filter (optical filter) described in Patent Document 1, an electrostatic actuator is disposed between a first substrate provided with a first reflective film and a second substrate provided with a second reflective film. By doing so, the gap between the reflective films is changed. Here, in this variable wavelength interference filter, an annular first electrode is disposed around the first reflective film of the first substrate, a second electrode is disposed around the first electrode, Around the second reflective film, a third electrode and a fourth electrode are disposed at positions facing the first electrode and the second electrode, respectively.
In such a wavelength variable interference filter, the electrostatic actuator composed of the first electrode and the third electrode and the electrostatic actuator composed of the second electrode and the fourth electrode can be driven independently. It becomes possible. As a result, this tunable interference filter can suppress sudden fluctuations in the gap between reflection films even when voltage changes such as noise occur, and the gap amount between reflection films can be accurately adjusted to the desired target wavelength. It becomes possible to set to.

JP 2011-191492 A

  By the way, the wavelength variable interference filter described in Patent Document 1 has a configuration in which two electrodes are arranged with different diameters around the reflective film. Therefore, although the accuracy of the gap control of the gap between the reflection films is improved, the electrode formation area is increased as compared with, for example, the wavelength variable interference filter in which one electrode is provided around the reflection film. There is a problem that the size of the.

  INDUSTRIAL APPLICABILITY In the present invention, a variable wavelength interference filter, an optical filter device, an optical module, an electronic apparatus, and a driving method for a variable wavelength interference filter that can perform gap control of a gap between reflection films with high accuracy and can be downsized The purpose is to provide.

  The wavelength tunable interference filter according to the present invention includes a first substrate, a second substrate disposed to face the first substrate, a conductive first reflective film provided on the first substrate, and the second substrate. A conductive second reflective film provided on the substrate and disposed to face the first reflective film via a gap between the reflective films; a first electrode provided on the first substrate; A second electrode provided on the second substrate and disposed opposite to the first electrode with an inter-electrode gap interposed therebetween, and the reflection by the first reflective film and the second reflective film A first electrostatic actuator that changes the gap amount of the inter-film gap is configured, and a second electrostatic actuator that changes the gap amount of the inter-reflection film gap is configured by the first electrode and the second electrode. It is characterized by.

In the present invention, the first reflective film provided on the first substrate and the second reflective film provided on the second substrate are opposed to each other with a gap between the reflective films, and these first reflective film and The second reflective film can extract light having a specific wavelength from incident light.
In the present invention, the first reflection film and the second reflection film have conductivity, and the first reflection film and the second reflection film constitute a first electrostatic actuator, which is provided on the first substrate. The second electrostatic actuator is configured by the first electrode and the second electrode provided on the second substrate. Therefore, the gap amount of the gap between the reflection films can be accurately set to a desired target value by these two electrostatic actuators.
Here, in this invention, since the 1st electrostatic actuator is comprised by the 1st reflective film and the 2nd reflective film, it is not necessary to provide an electrode in a 1st board | substrate and a 2nd board | substrate separately. That is, it is not necessary to provide an electrode constituting the electrostatic actuator other than the first electrode and the second electrode constituting the second electrostatic actuator, and the electrode formation area can be reduced. Thereby, size reduction of the wavelength variable interference filter can be achieved.
Moreover, in this invention, since a 1st reflective film and a 2nd reflective film are used as a 1st electrostatic actuator, an electrostatic attraction can be made to act directly with respect to the formation position of a reflective film. Therefore, when a voltage is applied to the first electrostatic actuator, the gap between the reflective films can be quickly changed, and the responsiveness can be improved.

In the wavelength variable interference filter according to the aspect of the invention, it is preferable that the gap between the reflection films and the gap between the electrodes have different gap amounts.
In the present invention, the gap between the reflective films and the gap between the electrodes are set to different values. In such a configuration, one of the first electrostatic actuator and the second electrostatic actuator having a small gap amount has a larger gap change amount (sensitivity) when a predetermined voltage is applied than the other one having a large gap amount. Become. By driving one of such high sensitivities and moving the gap between the reflection films to the vicinity of the target gap amount, the voltage during driving can be reduced.
In addition, the sensitivity of the other of the first electrostatic actuator and the second electrostatic actuator having a larger gap amount is smaller than that of the other having a smaller gap amount. Therefore, when the gap amount is finely adjusted and set to the target gap amount, highly accurate gap control can be performed.

In the wavelength variable interference filter according to the aspect of the invention, it is preferable that the gap between the reflection films is smaller than the gap between the electrodes.
In the present invention, the gap between the reflective films is set smaller than the gap between the electrodes. With such a configuration, it is possible to achieve both reduction of the driving voltage and highly accurate gap control, as in the above-described invention.
Further, when the gap between the reflective films is larger than the gap between the electrodes, the gap amount between the reflective films is set to be equal to or less than the minimum gap amount of the gap between the electrodes (the state in which the second substrate is most bent to the first substrate). I can't. For this reason, light with a low wavelength cannot be extracted, and the wavelength range of light that can be extracted with the variable wavelength interference filter may be narrowed. In contrast, in the present invention, since the gap between the reflective films is smaller than the gap between the electrodes, the wavelength range of light that can be extracted by the wavelength tunable interference filter can be expanded.

In the wavelength tunable interference filter according to the aspect of the invention, it is preferable that the first reflection film and the second reflection film are made of a metal alloy film.
In the present invention, since the metal alloy film is used as the first reflective film and the second reflective film, these first reflective film and second reflective film can function as an electrode as they are. Accordingly, a manufacturing process such as separately providing a conductive film member on the first reflective film or the second reflective film is not required, and the manufacturing efficiency of the wavelength variable interference filter can be improved.

In the wavelength tunable interference filter according to the aspect of the invention, it is preferable that the first reflective film and the second reflective film are configured by a laminate of a dielectric multilayer film and a conductive film.
In the present invention, the first reflective film and the second reflective film are constituted by a laminate of a dielectric multilayer film and a conductive film. When such a dielectric multilayer film is used, the reflectivity of the first reflective film or the second reflective film can be made extremely high depending on the film thickness setting and the number of film layers of each dielectric film, and the wavelength variable interference filter Resolution can be improved.
Moreover, although such a dielectric multilayer film does not have electroconductivity, it can make electroconductivity in a 1st reflective film and a 2nd reflective film by laminating | stacking a conductive film separately.

  The optical filter device of the present invention is provided on the first substrate, the second substrate disposed to face the first substrate, the conductive first reflective film provided on the first substrate, and the second substrate. A conductive second reflective film disposed opposite the first reflective film with a gap between the reflective films, a first electrode provided on the first substrate, and provided on the second substrate A wavelength tunable interference filter comprising a second electrode disposed to face the first electrode with an inter-electrode gap interposed therebetween, and a housing for housing the wavelength tunable interference filter, A first electrostatic actuator that changes a gap amount of the gap between the reflection films is configured by the first reflection film and the second reflection film, and the gap between the reflection films is formed by the first electrode and the second electrode. Second electrostatic actuator to change the amount Yueta is characterized in that it is configured.

In the present invention, similarly to the above-described invention, since the electrode formation area in the wavelength tunable interference filter can be reduced, the wavelength tunable interference filter can be reduced in size. Thereby, the size of the housing for housing the wavelength variable interference filter can be reduced, and the optical filter device can be reduced in size.
In addition, since the wavelength tunable interference filter is housed in the housing, it is possible to suppress the entry of foreign substances such as charged substances and water particles. Thereby, the fluctuation | variation of the gap between 1st reflective films by the adhesion of the charged substance to a reflective film and the gap between 2nd reflective films, and deterioration of each reflective film can be prevented. In addition, the wavelength tunable interference filter can be protected during transportation, and the work efficiency when the wavelength tunable interference filter is incorporated into equipment can be improved.

  The optical module of the present invention includes a first substrate, a second substrate disposed to face the first substrate, a conductive first reflective film provided on the first substrate, and the second substrate. A conductive second reflective film, disposed opposite to the first reflective film via a gap between the reflective films, a first electrode provided on the first substrate, and the second A second electrode provided on the substrate and arranged to face the first electrode with an inter-electrode gap interposed therebetween; and a voltage control unit, and the first reflective film and the second reflective film A first electrostatic actuator that changes a gap amount of the gap between the reflection films is configured, and a second electrostatic actuator that changes the gap amount of the gap between the reflection films is configured by the first electrode and the second electrode. And the voltage controller is configured to transmit the first electrostatic actuator. Ta, and the second electrostatic actuator, and applying an independent voltage.

In the present invention, similarly to the above-described invention, since the electrode formation area in the wavelength tunable interference filter can be reduced, the wavelength tunable interference filter can be reduced in size. As a result, the size of the optical module including the variable wavelength interference filter can be reduced.
In addition, since the voltage control unit can drive the first electrostatic actuator and the second electrostatic actuator of the variable wavelength interference filter independently of each other, the gap control of the gap between the reflective films is performed with high accuracy. be able to. Further, as described above, since the electrostatic attractive force can be directly applied to the first reflective film and the second reflective film, the responsiveness can be improved, and light of a desired target wavelength can be quickly emitted from the optical module. Can be taken out.

  In the optical module of the present invention, the voltage control unit includes a bias voltage applying unit that applies a preset bias voltage to one of the first electrostatic actuator and the second electrostatic actuator. A gap detecting means for detecting a gap amount of the gap between the reflective films, and the gap detecting means for the other of the first electrostatic actuator and the second electrostatic actuator to which the bias voltage is not applied. It is preferable to include a feedback voltage applying unit that applies a feedback voltage corresponding to the gap amount detected by.

In the present invention, the bias voltage application means of the voltage controller applies a preset bias voltage to either the first electrostatic actuator or the second electrostatic actuator. Then, the feedback voltage applying means is configured so that the gap between the reflection films (detection gap) detected by the gap detection means is the first electrostatic actuator or the second electrostatic actuator so that the gap between the reflection films becomes the target gap amount. On the other hand, a feedback voltage is applied.
That is, in the present invention, by applying a bias voltage to one of the electrostatic actuators, the gap between the reflective films is displaced to the vicinity of the target gap amount, and the gap detection unit is configured so that the gap between the reflective films becomes the target gap amount. The feedback voltage is finely adjusted based on the detected gap amount.
In such a configuration, since a feedback voltage to be applied to the other electrostatic actuator is set after a bias voltage is applied to one electrostatic actuator, the feedback voltage is applied to the other electrostatic actuator by the feedback voltage applying means. The sensitivity at the time of doing can be reduced. Thereby, the fine adjustment of the gap amount at the time of feedback control can be performed with higher accuracy. In addition, since it is possible to finely adjust the gap amount with high accuracy over a wide gap range while keeping the gain in the feedback voltage application means fixed, a configuration for changing the gain in the feedback voltage application means is unnecessary. Thus, the configuration can be simplified.
Even if the digital voltage is applied to the second electrostatic actuator as the feedback voltage applying means, the number of bits in the D / A converter can be reduced, so that the cost can be reduced.

  In the optical module of the present invention, the gap between the reflective films between the first reflective film and the second reflective film constituting the first electrostatic actuator, and the first electrode constituting the second electrostatic actuator. And the interelectrode gap between the second electrodes has a different gap amount, and the bias voltage applying means has a smaller gap amount between the first electrostatic actuator and the second electrostatic actuator. Preferably, the bias voltage is applied to one side, and the feedback voltage application unit applies the feedback voltage to the other of the first electrostatic actuator and the second electrostatic actuator having the larger gap amount.

In the present invention, a bias voltage is applied to one of the first electrostatic actuator and the second electrostatic actuator that has a small gap amount between the electrodes (or between the reflective films). In such a configuration, the gap between the reflection films can be greatly displaced with a small bias voltage.
Further, a feedback voltage is applied to the other one of the first electrostatic actuator and the second electrostatic actuator that has a large gap amount between the electrodes (or between the reflective films). In this case, since the sensitivity (gap change amount with respect to the unit applied voltage) when the electrostatic actuator is driven is reduced by the amount of the gap, the gap control with higher accuracy can be performed.

  An electronic apparatus according to the present invention includes a first substrate, a second substrate disposed to face the first substrate, a conductive first reflective film provided on the first substrate, and the second substrate. A conductive second reflective film, disposed opposite to the first reflective film via a gap between the reflective films, a first electrode provided on the first substrate, and the second A detection unit that is provided on the substrate and detects the second electrode disposed to face the first electrode with an inter-electrode gap interposed therebetween, and the light extracted by the first reflection film and the second reflection film. The first electrostatic actuator that changes the gap amount of the gap between the reflective films is constituted by the first reflective film and the second reflective film, and the first electrode and the second electrode, Second electrostatic actuator for changing gap amount of gap between reflection films Wherein the but has been configured.

In the present invention, similarly to the above-described invention, since the electrode formation area in the wavelength tunable interference filter can be reduced, the wavelength tunable interference filter can be reduced in size. Thereby, the size of the electronic device provided with the variable wavelength interference filter can be reduced.
In addition, since the electrostatic attractive force can be directly applied to the first reflective film and the second reflective film, the response can be improved and light of the target wavelength can be extracted from the wavelength variable interference filter more quickly. In the electronic device, various processes can be performed more quickly based on the extracted light.

  The wavelength tunable interference filter driving method of the present invention includes a first substrate, a second substrate disposed opposite to the first substrate, a conductive first reflective film provided on the first substrate, and the second substrate. A conductive second reflective film disposed on the substrate and disposed to face the first reflective film via a gap between the reflective films; a first electrode provided on the first substrate; and A second electrode provided on the second substrate and disposed opposite to the first electrode with an inter-electrode gap interposed between the reflective film and the first reflective film; A wavelength variable interference in which a first electrostatic actuator for changing a gap amount of the gap is configured, and a second electrostatic actuator for changing the gap amount of the gap between the reflection films is configured by the first electrode and the second electrode. A driving method of the filter, A bias voltage applying step for applying a preset bias voltage to either the first electrostatic actuator or the second electrostatic actuator, and a gap for detecting a gap amount of the gap between the reflection films And a feedback voltage corresponding to the gap amount detected by the gap detecting means is applied to the other of the first electrostatic actuator and the second electrostatic actuator to which the bias voltage is not applied. And performing a feedback voltage applying step.

  In the present invention, a gap detection step for detecting the gap amount of the gap between the reflective films is performed in a state where the bias voltage is applied to one of the first electrostatic actuator and the second electrostatic actuator by the bias voltage application step. The feedback voltage according to the gap amount detected by the gap detection step is applied to the other one of the first electrostatic actuator and the second electrostatic actuator by the feedback voltage application step. For this reason, in the feedback voltage application step, the sensitivity at the time of voltage application can be reduced, and fine adjustment of the gap amount can be performed with high accuracy.

1 is a block diagram showing a schematic configuration of a spectrometer according to a first embodiment of the present invention. The block diagram which shows schematic structure of the optical module of 1st embodiment. The top view which shows schematic structure of the wavelength variable interference filter of 1st embodiment. FIG. 4 is a cross-sectional view of the variable wavelength interference filter of FIG. 3 taken along line AA ′. The top view which looked at the stationary substrate from the movable substrate side in 1st embodiment. The figure which showed an example of the laminated structure of the fixed reflection film in the case of using a dielectric multilayer film as a reflection film. The top view which looked at the movable substrate from the fixed substrate side in the first embodiment. The flowchart which shows the drive method (drive process) of the wavelength variable interference filter in the spectrum measurement process of the spectrometer of 1st embodiment. The figure for demonstrating the sensitivity of the 2nd electrostatic actuator at the time of applying the bias voltage applied to a 1st electrostatic actuator at the time of feedback control. Sectional drawing which shows schematic structure of the optical filter device which concerns on 2nd embodiment. FIG. 2 is a schematic diagram illustrating a color measurement device that is an example of an electronic apparatus according to the invention. Schematic which shows the gas detection apparatus which is an example of the electronic device of this invention. The block diagram which shows the structure of the control system of the gas detection apparatus of FIG. The figure which shows schematic structure of the food analyzer which is an example of the electronic device of this invention. 1 is a diagram showing a schematic configuration of a spectroscopic camera which is an example of an electronic apparatus of the present invention.

[First embodiment]
Hereinafter, a first embodiment according to the present invention will be described with reference to the drawings.
[Configuration of Spectrometer]
FIG. 1 is a block diagram showing a schematic configuration of the spectrometer according to the first embodiment of the present invention.
The spectroscopic measurement apparatus 1 is the electronic apparatus of the present invention, and analyzes the light intensity of a predetermined wavelength in the measurement target light reflected by the measurement target X to measure a spectral spectrum.
As shown in FIG. 1, the spectrometer 1 includes an optical module 10, a detector 11 (detection unit), an IV converter 12, an amplifier 13, an A / D converter 14, and a control unit 20. And. The optical module 10 includes a variable wavelength interference filter 5 and a voltage control unit 15.

The detector 11 receives the light transmitted through the wavelength variable interference filter 5 of the optical module 10 and outputs a detection signal (current) corresponding to the light intensity of the received light.
The IV converter 12 converts the detection signal input from the detector 11 into a voltage value and outputs the voltage value to the amplifier 13.
The amplifier 13 amplifies a voltage (detection voltage) corresponding to the detection signal input from the IV converter 12.
The A / D converter 14 converts the detection voltage (analog signal) input from the amplifier 13 into a digital signal and outputs it to the control unit 20.

[Configuration of optical module]
Next, the configuration of the optical module 10 will be described below.
FIG. 2 is a block diagram illustrating a schematic configuration of the optical module 10.
As described above, the optical module 10 includes the variable wavelength interference filter 5 and the voltage control unit 15.

[Configuration of wavelength tunable interference filter]
The wavelength variable interference filter 5 of the optical module 10 will be described below. FIG. 3 is a plan view showing a schematic configuration of the variable wavelength interference filter 5. 4 is a cross-sectional view of the tunable interference filter of FIG. 3 taken along line AA ′.
As shown in FIGS. 3 and 4, the variable wavelength interference filter 5 is a rectangular plate-shaped optical member, for example, and includes a fixed substrate 51 (first substrate) and a movable substrate 52 (second substrate). The fixed substrate 51 and the movable substrate 52 are each formed of various types of glass, crystal, or the like, and the first bonding portion 513 of the fixed substrate 51 and the second bonding portion 523 of the movable substrate 52 are, for example, plasma mainly composed of siloxane. By being joined by a joining film 53 (see FIG. 4) made of a polymer film or the like, it is integrally constructed.

The fixed substrate 51 is provided with a fixed reflective film 541 constituting the first reflective film of the present invention, and the movable substrate 52 is provided with a movable reflective film 542 constituting the second reflective film of the present invention. The fixed reflection film 541 and the movable reflection film 542 are disposed to face each other via a gap G1 between reflection films (see FIG. 4).
The fixed substrate 51 is provided with a first electrode 551, and the movable substrate 52 is provided with a second electrode 552. The first electrode 551 and the second electrode 552 are disposed to face each other via an interelectrode gap G2 (see FIG. 4).
Here, the fixed reflection film 541 and the movable reflection film 542 have conductivity, and the first electrostatic actuator 54 is configured by the fixed reflection film 541 and the movable reflection film 542. The first electrode 551 and the second electrode 552 constitute a second electrostatic actuator 55.

  In the following description, the wavelength tunable interference filter 5 was seen from a plan view seen from the thickness direction of the fixed substrate 51 or the movable substrate 52, that is, from the stacking direction of the fixed substrate 51, the bonding film 53, and the movable substrate 52. The plan view is referred to as a filter plan view. In the present embodiment, the center point of the fixed reflection film 541 and the center point of the movable reflection film 542 coincide with each other in the filter plan view, and the center point of these reflection films in the plan view is referred to as a filter center point O. A straight line passing through the center point of these reflective films is referred to as a central axis.

(Configuration of fixed substrate)
FIG. 5 is a plan view of the fixed substrate 51 as viewed from the movable substrate 52 side.
The fixed substrate 51 is formed larger in thickness than the movable substrate 52, and electrostatic attraction by the electrostatic actuators 54 and 55 and a film member formed on the fixed substrate 51 (for example, the fixed reflection film 541 and the like). The fixed substrate 51 is not bent due to the internal stress.
As shown in FIGS. 4 and 5, the fixed substrate 51 includes an electrode arrangement groove 511 and a reflective film installation portion 512 formed by, for example, etching. Further, one end side (side C1-C2 in FIGS. 3 and 5) of the fixed substrate 51 protrudes outward from the substrate edge (side C5-C6 in FIGS. 3 and 5) of the movable substrate 52. One terminal extraction part 514 is constituted.

The electrode arrangement groove 511 is formed in an annular shape centering on the filter center point O of the fixed substrate 51 in the filter plan view. The reflection film installation part 512 is formed so as to protrude from the center part of the electrode arrangement groove 511 toward the movable substrate 52 in the filter plan view. The groove bottom surface of the electrode arrangement groove 511 serves as an electrode installation surface 511A on which the first electrode 551 of the second electrostatic actuator 55 is arranged. In addition, the protruding front end surface of the reflection film installation portion 512 is a reflection film installation surface 512A.
The fixed substrate 51 is provided with an electrode extraction groove 511 </ b> B extending from the electrode arrangement groove 511 toward the outer peripheral edge of the fixed substrate 51.

A first electrode 551 constituting the second electrostatic actuator 55 is provided on the electrode installation surface 511 </ b> A of the electrode arrangement groove 511. The first electrode 551 is provided in a region of the electrode installation surface 511 </ b> A that faces a movable portion 521 described later. The first electrode 551 is formed in an arc shape (substantially C shape), and as shown in FIG. 5, a C-shaped opening is provided in a part close to the side C1-C2. In addition, an insulating film for ensuring insulation between the first electrode 551 and the second electrode 552 may be stacked.
As shown in FIG. 5, the fixed substrate 51 is provided with a first extraction electrode 553 that extends from one end of the first electrode 551 toward the first terminal extraction portion 514. The first extraction electrode 553 is disposed along the electrode extraction groove 511 </ b> B and extends to the top of the first terminal extraction portion 514. And the extended front-end | tip part of the 1st extraction electrode 553 is connected to the feedback control part 153 mentioned later of the voltage control part 15 by FPC (Flexible printed circuits), a lead wire, etc., for example.

As described above, the reflective film installation portion 512 is formed in a substantially cylindrical shape that is coaxial with the electrode arrangement groove 511 and has a smaller diameter than the electrode arrangement groove 511, and is formed on the movable substrate 52 of the reflection film installation portion 512. An opposing reflection film installation surface 512A is provided.
As shown in FIGS. 4 and 5, a fixed reflection film 541 is installed in the reflection film installation portion 512. As the fixed reflective film 541, for example, a metal film such as Ag or a conductive alloy film such as an Ag alloy can be used. Deterioration due to oxidation or the like can be suppressed, and the visible light region to the near infrared light region can be used. It is more preferable to use an Ag alloy film having high reflection characteristics with respect to a wide wavelength band extending over the range.
By the way, in this embodiment, since the 1st electrostatic actuator 54 is comprised by the fixed reflection film 541 and the movable reflection film 542, an electrostatic attraction acts directly with respect to the fixed reflection film 541 and the movable reflection film 542. In this case, when a film material having relatively low adhesion to glass is used as the fixed reflective film 541, the fixed reflective film 541 may be peeled off due to repeated electrostatic attraction acting, for example, after long-term use. Therefore, for example, an adhesive layer having high adhesion to the fixed substrate 51 (glass) and the fixed reflective film 541 and having translucency in the wavelength range to be measured is provided with the fixed reflective film 541 and the reflective film. It is good also as a structure provided between surface 512A. As such an adhesive layer, for example, when an Ag alloy is used as the fixed reflective film 541, an ITO (tin-doped indium oxide) film or the like can be used as the adhesive layer.

As the fixed reflective film 541, for example, a dielectric multilayer film in which the high refractive layer is TiO ₂ and the low refractive layer is SiO ₂ may be used. FIGS. 6A and 6B are diagrams showing an example of a laminated structure of the fixed reflective film 541 in the case where a dielectric multilayer film is used as the reflective film.
In the case where the dielectric multilayer film 541A is used as the fixed reflective film 541, as shown in FIG. 6A, a conductive film 541B is laminated on the lowermost layer of the dielectric multilayer film 541A. 6B, a conductive film 541B may be stacked on the uppermost layer (surface layer) of the dielectric multilayer film 541A. In such a configuration, even if the dielectric multilayer film 541A has no conductivity, the conductive film 541B can make the fixed reflective film 541 conductive.
6A, as the conductive film 541B, the first layer of the dielectric multilayer film (the layer disposed closest to the fixed substrate 51) and the fixed substrate 51 are used. It is preferable to use a conductive material having good adhesion. In the case of using the structure as shown in FIG. 6B, the conductive film 541B has a good adhesion with respect to the uppermost layer of the dielectric multilayer film (the layer disposed closest to the movable substrate 52). It is preferable to use a material. Examples of such a conductive film 541B include an ITO film.
Note that, as the conductive film 541B, a reflective film such as an Ag alloy having high reflectance characteristics with respect to the wavelength range to be measured may be used. In this case, the conductive film 541B can widen the measurement target wavelength range of the wavelength tunable interference filter 5, it is possible to extract a desired target wavelength with respect to a wide wavelength band, and the dielectric multilayer film 541A. It becomes possible to extract light of a target wavelength with high resolution. In this case, a transparent adhesive layer may be further interposed between the conductive film 541B and the reflective film installation portion 512 and between the conductive film 541B and the dielectric multilayer film 541A in order to improve adhesion.

As shown in FIG. 5, the fixed substrate 51 is connected to the outer peripheral edge of the fixed reflection film 541, passes through the C-shaped opening of the first electrode 551, and extends toward the first terminal extraction portion 514. A fixed extraction electrode 543 is provided. The fixed-side extraction electrode 543 is formed by being formed at the same time as the fixed reflection film 541 is formed.
Further, as shown in FIG. 6, when the fixed reflective film 541 is formed of a laminate of a dielectric multilayer film 541A and a conductive film 541B, the fixed-side extraction electrode 543 is formed simultaneously with the conductive film 541B. , Connected to the conductive film 541B.
For example, the fixed-side extraction electrode 543 branches into a driving extraction electrode 543A and a detection extraction electrode 543B in the electrode extraction groove 511B. The leading ends of the drive lead electrode 543A and the detection lead electrode 543B are disposed on the first terminal lead portion 514, and are connected to the voltage control portion 15 by, for example, an FPC or a lead wire. Although details will be described later, the drive extraction electrode 543A is connected to the bias drive unit 151 of the voltage control unit 15, and the detection extraction electrode 543B is connected to the gap detector 152 of the voltage control unit 15.

  Further, an antireflection film may be formed at a position corresponding to the fixed reflection film 541 on the light incident surface of the fixed substrate 51 (the surface on which the fixed reflection film 541 is not provided). This antireflection film can be formed by alternately laminating low refractive index films and high refractive index films, and reduces the reflectance of visible light on the surface of the fixed substrate 51 and increases the transmittance.

  Of the surfaces of the fixed substrate 51 facing the movable substrate 52, the surfaces on which the electrode placement groove 511, the reflective film installation portion 512, and the electrode extraction groove 511 </ b> B are not formed constitute the first joint portion 513. The first bonding portion 513 is bonded to the second bonding portion 523 of the movable substrate 52 by the bonding film 53.

(Configuration of movable substrate)
FIG. 7 is a plan view of the movable substrate 52 as viewed from the fixed substrate 51 side.
The movable substrate 52 includes a circular movable portion 521 centered on the filter center point O in the filter plan view as shown in FIG. 3, a holding portion 522 that is coaxial with the movable portion 521 and holds the movable portion 521, A substrate outer peripheral portion 525 provided outside the holding portion 522.
Further, as shown in FIG. 3, the movable substrate 52 has one end side (side C3-C4 in FIGS. 3 and 7) at the substrate edge of the fixed substrate 51 (side C7-C8 in FIGS. 3 and 4). 2nd terminal extraction part 524 is constituted.

The movable part 521 is formed to have a thickness dimension larger than that of the holding part 522. For example, in this embodiment, the movable part 521 is formed to have the same dimension as the thickness dimension of the movable substrate 52. The movable portion 521 is formed to have a diameter larger than at least the diameter of the outer peripheral edge of the reflection film installation surface 512A in the filter plan view. A movable reflective film 542 and a second electrode 552 are provided on the movable surface 521A of the movable portion 521 facing the fixed substrate 51.
Similar to the fixed substrate 51, an antireflection film may be formed on the surface of the movable portion 521 opposite to the fixed substrate 51.

The second electrode 552 is provided on the outer peripheral side of the movable reflective film 542 in the filter plan view, and is disposed to face the first electrode 551 via the inter-electrode gap G2. The second electrode 552 is formed in an arc shape (substantially C shape), and as shown in FIG. 7, a C-shaped opening is provided in a part close to the side C3-C4. Similarly to the first electrode 551, an insulating film may be stacked over the second electrode 552.
Here, as shown in FIG. 3, in the filter plan view, the second electrostatic actuator 55 is formed by an arc region where the second electrode 552 and the first electrode 551 overlap (region indicated by a hatched portion rising to the right in FIG. 3). Is configured. As shown in FIG. 3, the second electrostatic actuator 55 has a shape and an arrangement that are symmetrical with respect to the filter center point O in the filter plan view. Accordingly, the electrostatic attractive force generated when a voltage is applied to the second electrostatic actuator 55 also acts at a point symmetric with respect to the filter center point O, and the movable portion 521 is displaced toward the fixed substrate 51 in a balanced manner. It becomes possible to make it.

  Further, as shown in FIG. 7, the movable substrate 52 is provided with a second extraction electrode 554 that extends from one end of the second electrode 552 toward the second terminal extraction portion 524. The second extraction electrode 554 is disposed along a position facing the electrode extraction groove 511B of the fixed substrate 51, and extends to the second terminal extraction portion 524. And the extended front-end | tip part of the 2nd extraction electrode 554 is connected to the feedback control part 153 mentioned later of the voltage control part 15 by FPC, a lead wire, etc., for example.

The movable reflective film 542 is provided at the center of the movable surface 521A of the movable part 521 so as to face the fixed reflective film 541 with the gap G1 between the reflective films. As the movable reflective film 542, a reflective film having the same configuration as that of the fixed reflective film 541 described above is used. In the present embodiment, the first electrode 551 is provided on the electrode installation surface 511A, and the fixed reflection film 541 is provided on the reflection film installation surface 512A located on the movable substrate 52 side with respect to the electrode installation surface 511A. The reflective film gap G1 is smaller than the interelectrode gap G2.
Further, as shown in FIG. 7, the movable substrate 52 is connected to the outer peripheral edge of the movable reflective film 542, passes through the C-shaped opening of the second electrode 552, and extends toward the second terminal extraction portion 524. A movable extraction electrode 544 is provided. The movable-side extraction electrode 544 is formed at the same time as the movable reflective film 542 is formed.
In the case where the movable reflective film 542 is formed of a laminate of a dielectric multilayer film and a conductive film, the movable-side extraction electrode 544 is formed simultaneously with the conductive film and connected to the conductive film.
Then, the movable-side extraction electrode 544 branches into a driving extraction electrode 544A and a detection extraction electrode 544B, for example, on the outer peripheral side of the holding portion 522. The leading ends of the drive lead electrode 544A and the detection lead electrode 544B are disposed on the second terminal lead portion 524, and are connected to the voltage control portion 15 by, for example, an FPC or a lead wire. . Although details will be described later, the drive extraction electrode 544A is connected to the bias drive unit 151 of the voltage control unit 15, and the detection extraction electrode 544B is connected to the gap detector 152 of the voltage control unit 15.

  In the present embodiment, as shown in FIG. 4, an example is shown in which the gap amount of the interelectrode gap G2 is larger than the gap amount of the inter-reflection film gap G1, but the present invention is not limited to this. For example, when the measurement target light is infrared light or far infrared light, the gap amount of the reflection film gap G1 is larger than the gap amount of the interelectrode gap G2 depending on the wavelength range of the measurement target light. It is good also as composition which becomes. In this case, the first extraction electrode 553 and the second extraction electrode 554 are connected to the bias drive unit 151 of the voltage control unit 15, and the drive extraction electrodes 543A and 544A are connected to the feedback control unit 153 of the voltage control unit 15. The

The holding part 522 is a diaphragm that surrounds the periphery of the movable part 521, and has a thickness dimension smaller than that of the movable part 521. Such a holding part 522 is easier to bend than the movable part 521, and the movable part 521 can be displaced toward the fixed substrate 51 by a slight electrostatic attraction. At this time, since the movable portion 521 has a thickness dimension larger than that of the holding portion 522 and becomes rigid, even when the holding portion 522 is pulled toward the fixed substrate 51 by electrostatic attraction, the shape of the movable portion 521 changes. Absent. Therefore, the movable reflective film 542 provided on the movable portion 521 is not bent, and the fixed reflective film 541 and the movable reflective film 542 can be always maintained in a parallel state.
In this embodiment, the diaphragm-like holding part 522 is illustrated, but the present invention is not limited to this. For example, a configuration in which beam-like holding parts arranged at equiangular intervals around the filter center point O are provided. And so on.

  As described above, the substrate outer peripheral portion 525 is provided outside the holding portion 522 in the filter plan view. A second bonding portion 523 facing the first bonding portion 513 is provided on the surface of the substrate outer peripheral portion 525 facing the fixed substrate 51, and is bonded to the first bonding portion 513 through the bonding film 53.

[Configuration of voltage controller]
As shown in FIG. 2, the voltage control unit 15 includes a bias drive unit 151 (bias voltage application unit), a gap detector 152 (gap detection unit), a feedback control unit 153 (feedback voltage application unit), and a microcomputer ( Microcontroller) 154.
The bias driving unit 151 is connected to the driving lead electrodes 543A and 544A of the variable wavelength interference filter 5 and applies a bias voltage to the first electrostatic actuator 54. Specifically, the bias driving unit 151 includes a D / A converter having a predetermined number of bits, and applies a voltage to the first electrostatic actuator 54 based on a bias signal input from the microcomputer 154.

The gap detector 152 is connected to the extraction electrodes 543B and 544B for detection of the variable wavelength interference filter 5, and acquires a detection signal corresponding to the gap amount of the inter-reflection film gap G1. Further, the gap detector 152 outputs the acquired detection signal to the feedback control unit 153.
The feedback control unit 153 is connected to the first extraction electrode 553 and the second extraction electrode 554 of the variable wavelength interference filter 5 and applies a feedback voltage to the second electrostatic actuator 55. At this time, the feedback control unit 153 controls the second electrostatic actuator 55 so that the detection signal input from the gap detector 152 and the target value (target detection signal) input from the microcomputer 154 have the same value. Apply the feedback voltage.
In addition, the feedback control unit 153 of the present embodiment is configured by an analog controller having a fixed gain, and the voltage variable range is set to a predetermined width. Such an analog controller can be incorporated with a simpler system configuration than an analog controller having a variable gain, for example, and cost reduction can be achieved. Here, for example, a PI controller or a PID controller can be used as the analog controller. Other controllers may be used.

The microcomputer 154 is connected to the control unit 20, the bias drive unit 151, the gap detector 152, and the feedback control unit 153. The microcomputer 154 includes storage means (not shown) configured by a memory or the like. In this storage means, for example, gap correlation data that is a detection signal (voltage signal) detected by the gap detector 152 with respect to the gap amount of the gap G1 between the reflection films is stored.
The microcomputer 154 controls the bias driving unit 151, the gap detector 152, and the feedback control unit 153 based on the control signal input from the control unit 20, and transmits light of the target wavelength from the wavelength variable interference filter 5. Let
A detailed description of the control of the driving voltage of the wavelength variable interference filter 5 by the voltage controller 15 will be described later.

[Configuration of control unit]
Returning to FIG. 1, the control unit 20 of the spectroscopic measurement apparatus 1 will be described.
The control unit 20 corresponds to a processing unit of the present invention, and is configured by combining, for example, a CPU and a memory, and controls the overall operation of the spectroscopic measurement apparatus 1. As illustrated in FIG. 1, the control unit 20 includes a wavelength setting unit 21, a light amount acquisition unit 22, and a spectroscopic measurement unit 23.

The wavelength setting unit 21 sets a target wavelength of light extracted by the wavelength variable interference filter 5, and outputs a control signal to the voltage control unit 15 to extract the set target wavelength from the wavelength variable interference filter 5.
The light quantity acquisition unit 22 acquires the light quantity of the target wavelength light transmitted through the wavelength variable interference filter 5 based on the light quantity acquired by the detector 11.
The spectroscopic measurement unit 23 measures the spectral characteristics of the light to be measured based on the light amount acquired by the light amount acquisition unit 22.

[Driving method of tunable interference filter]
FIG. 8 is a flowchart showing a driving method (driving process) of the variable wavelength interference filter in the spectroscopic measurement process of the spectroscopic measurement apparatus 1.
In order to acquire the intensity of light of each wavelength included in the measurement target light by the spectroscopic measurement device 1, first, the control unit 20 uses the wavelength setting unit 21 to transmit the wavelength of light that passes through the wavelength variable interference filter 5 (target wavelength). ) Is set. And the wavelength setting part 21 outputs the control signal to the effect of transmitting the light of the set target wavelength to the voltage control part 15 (S1).

When the control signal is input from the control unit 20, the microcomputer 154 of the voltage control unit 15 calculates a bias voltage corresponding to the target wavelength (S2).
Here, in the present embodiment, the microcomputer 154 makes the sensitivity (gap displacement amount (m / V) with respect to the applied voltage) constant when the voltage is applied to the second electrostatic actuator 552 in feedback control described later. Set the bias voltage.
Here, the sensitivity R _C (m / V) when a voltage is applied to the second electrostatic actuator 55 is expressed by the following equation (1).

In the above formula (1), V _m is a bias voltage applied to the first electrostatic actuator 54, k is a spring coefficient of the movable substrate 52 (holding part 522), and ε is between the fixed substrate 51 and the movable substrate 52 ( area of the dielectric constant of the reflecting film gap G1 and the inter-electrode gap G2), S ₁ is the area where fixed reflection film 541 and the movable reflection film 542 in the filter plan view overlap each other (region functioning as a first electrostatic actuator 54) , _{S 2} is the area of the region where the first electrode 551 and second electrode 552 overlap each other in the filter plan view (region functioning as a second electrostatic actuator _{55), d max1} the initial gap amount of the gap G1 between the reflective films , D _max2 is the initial gap amount of the interelectrode gap G2 (gap amount when no voltage is applied), d is the light of the target wavelength This is the amount of displacement of the movable portion 521 for transmission (the amount of change in the gap between the reflection film gap G1 and the gap between electrodes G2).

In the present embodiment, during feedback control, the bias voltage _Vm is applied so that the sensitivity at the time of voltage application to the second electrostatic actuator 55 is constant. That is, in the above equation (2), _RC is a constant value, and a preset value corresponding to the fixed gain in the analog controller of the feedback control unit 153 is used.
Further, when a control signal designating the target wavelength is input from the control unit 20, the microcomputer 154 sets the target gap amount of the inter-reflective film gap G <b> 1 necessary for extracting the light of the target wavelength from the wavelength variable interference filter 5. The amount by which the movable part 521 is to be displaced (target displacement amount d) can be calculated from the target gap amount.
Therefore, in S2, the microcomputer 154 applies the voltage applied to the first electrostatic actuator 54 (which is required to drive the second electrostatic actuator 55 with a predetermined sensitivity in feedback control based on the equation (1)). Bias voltage V _m ) is calculated.

  Then, the microcomputer 154 outputs a bias signal based on the bias voltage calculated in S2 to the bias driver 151. As a result, the bias drive unit 151 applies the bias voltage calculated in S2 to the first electrostatic actuator 54 (S3: bias voltage application step). By this S3, an electrostatic attractive force based on the bias voltage acts between the fixed reflection film 541 and the movable reflection film 542, and the movable portion 521 is displaced toward the fixed substrate 51 side.

Here, FIG. 9 is a diagram for explaining the sensitivity of the second electrostatic actuator 55 when a bias voltage applied to the first electrostatic actuator 54 is applied during feedback control.
As shown by the broken line in FIG. 9A, the sensitivity of the second electrostatic actuator 55 that applies the feedback voltage is the amount of displacement (the displacement of the movable portion 521 when no bias voltage is applied to the first electrostatic actuator 54). The sensitivity changes greatly with respect to (amount), and the sensitivity increases as the amount of displacement increases. In this way, when the sensitivity of the electrostatic actuator that applies the feedback voltage changes, even if the gain of the analog controller is set in accordance with a specific sensitivity, the sensitivity increases as the displacement increases. The analog controller does not function properly. That is, in the state where no bias voltage is applied, the analog controller functions properly only in the vicinity of the gap where the gain is set.
On the other hand, in the present embodiment, as shown in FIG. 9B, by applying a bias voltage based on the equation (1) to the first electrostatic actuator 54, the solid line in FIG. As shown, the sensitivity of the second electrostatic actuator 55 is constant at the desired sensitivity _RC1 .
In this embodiment, an example in which a bias voltage is applied so that the sensitivity _RC is constant has been described. However, the value of the bias voltage is not limited to the value based on the expression (1), and a desired sensitivity characteristic is obtained. Thus, a bias voltage may be applied.

Thereafter, feedback control (S4 to S7) is performed by the feedback control unit 153.
In the feedback control, the microcomputer 154 applies a high-frequency voltage signal for capacitance detection between the fixed reflection film 541 and the movable reflection film 542 from the gap detector 152. Here, as the voltage signal for capacitance detection, a voltage having a sufficiently high frequency compared to the bias voltage is used in order to suppress fluctuations in electrostatic attraction due to the capacitance detection signal.
Thereby, a detection signal corresponding to the electrostatic capacities of the fixed reflection film 541 and the movable reflection film 542 is input to the gap detector 152 (S4: gap detection step). As the gap detector 152, for example, a voltage signal for capacitance detection and a voltage signal for bias voltage are separated by a circuit using a coupling capacitor or the like, and a voltage signal for capacitance detection is detected. Get as a signal. Here, this detection signal is a signal based on the gap amount of the gap G1 between the reflection films. Therefore, acquiring the detection signal by the gap detector 152 means that the gap detector 152 detects the gap amount of the inter-reflective film gap G1.
Further, the gap detector 152 outputs the input detection signal to the feedback control unit 153.

On the other hand, when the control signal from the control unit 20 is input in S1, the microcomputer 154 calculates a target gap amount corresponding to the target wavelength, and corresponds to the target gap amount from the gap correlation data stored in the storage unit. A detection signal (target detection signal) is acquired and output to the feedback control unit 153.
Then, the feedback control unit 153 calculates a deviation between the target detection signal input from the microcomputer 154 and the detection signal input from the gap detector 152 (S5), and determines whether or not the deviation is “0”. Determine (S6).
When it is determined in S6 that the deviation is not “0”, the feedback control unit 153 sets a feedback voltage according to the deviation and applies the set feedback voltage to the second electrostatic actuator 55. (S7: Feedback voltage application step).

  In S7, the feedback voltage application unit 153 determines that the deviation is zero based on the deviation between the target value signal input from the microcomputer 154 and the signal output from the gap detector in S7. The feedback voltage applied to 55 is set. At this time, as shown in FIG. 9, in the present embodiment, a bias voltage is applied to the first electrostatic actuator 54 so that the sensitivity of the second electrostatic actuator 55 is constant. Therefore, the second electrostatic actuator 55 can be driven with low sensitivity regardless of the displacement amount of the movable portion 521 (change amount of the interelectrode gap G2).

Then, after S7, the process returns to S4. That is, the voltage control unit 15 repeatedly performs the processes of S4 to S7 until the deviation is determined to be “0” in S6.
If it is determined in S6 that the deviation is “0”, the control unit 20 of the spectroscopic measurement apparatus 1 causes the detector 11 to detect the light transmitted through the wavelength variable interference filter 5 (S8). Thereby, it becomes possible to acquire the light quantity of the light of the target wavelength set by the wavelength setting unit 21 of the control unit 20.
In the above description, the process of taking out light of one wavelength from the wavelength variable interference filter 5 and detecting the amount of light has been described. For example, the light to be measured is determined from the light amount for each wavelength within a predetermined wavelength range included in the light to be measured. In the case of measuring the spectral spectrum, the wavelengths set in S1 are sequentially changed, and the above S2 to S8 processes are repeated.

[Operational effects of this embodiment]
In the variable wavelength interference filter 5 of the present embodiment, the first electrostatic actuator 54 is configured by the fixed reflective film 541 provided on the fixed substrate 51 and the movable reflective film 542 provided on the movable substrate 52. A second electrostatic actuator 55 is configured by the first electrode 551 provided on the second electrode 552 and the second electrode 552 provided on the movable substrate 52. In addition, the first electrostatic actuator 54 and the second electrostatic actuator 55 can be driven independently of each other, whereby a highly accurate gap G1 between the reflecting films formed by the two electrostatic actuators. Control can be implemented.
In the present embodiment, the fixed reflective film 541 and the movable reflective film 542 function as the first electrostatic actuator 54, so that the electrode shape can be simplified and the electrode formation area can be reduced. Thereby, the wavelength variable interference filter 5 can be reduced in size, and accordingly, the optical module 10 and the spectroscopic measurement apparatus 1 can be reduced in size.
Further, in the configuration in which the fixed reflective film 541 and the movable reflective film 542 function as the first electrostatic actuator 54, an electrostatic attractive force can be directly applied to the fixed reflective film 541 and the movable reflective film 542. Thereby, responsiveness can be improved when changing the gap G1 between reflective films.

In the present embodiment, the reflection-film gap G1 between the fixed reflection film 541 and the movable reflection film 542 constituting the first electrostatic actuator 54, and the first electrode 551 and the second electrode 552 constituting the second electrostatic actuator 55. The gap G2 between the electrodes is a different gap amount, and the gap G1 between the reflection films is set to be smaller than the gap G2 between the electrodes.
In the conventional configuration in which two electrostatic actuators having the same inter-electrode gap are arranged around the reflective film, the bias voltage needs to be set larger if the inter-electrode gap is increased in order to reduce the sensitivity during feedback control. As a result, the drive voltage increases. Further, if the gap between the electrodes is reduced in order to reduce the driving voltage, the sensitivity during feedback control is increased and the gap control becomes difficult.
On the other hand, in this embodiment, since the gap G1 between the reflection films is smaller than the gap G2 between the electrodes, the movable part is moved by the bias voltage application step by applying the bias voltage to the first electrostatic actuator 54. The drive voltage when 521 is displaced to the vicinity of the target gap amount can be reduced, and power saving can be achieved. Further, by applying a feedback voltage to the second electrostatic actuator 55, the sensitivity at the time of feedback control can be reduced, and highly accurate gap control can be performed.
That is, in this embodiment, it is possible to achieve both power saving and highly accurate gap control of the gap G1 between the reflective films.

  Further, when the inter-reflection film gap G1 is larger than the inter-electrode gap G2, the inter-reflection film gap G1 cannot be set to be equal to or smaller than the inter-electrode gap G2, and the wavelength of light that can be extracted by the wavelength variable interference filter 5 There is a risk that the band will be narrowed. On the other hand, by setting the gap G1 between the reflection films to be smaller than the gap G2 between the electrodes as in this embodiment, the settable range of the gap G1 between the reflection films can be expanded, and the wavelength variable interference filter 5 Thus, the wavelength range of light that can be extracted can be expanded.

In this embodiment, an Ag alloy film is used as the fixed reflective film 541 and the movable reflective film 542.
When such an Ag alloy film is used as a reflection film, there is no need to provide a separate electrode on the reflection film or between the reflection film and the substrate, and the fixed reflection film 541 that easily functions as both the reflection film and the electrode, and A movable reflective film 542 can be formed. Therefore, the structure can be simplified and the production efficiency can be improved.
Further, since the Ag alloy film has a high reflectance characteristic from the visible light to the near infrared light region, the wavelength band of light that can be extracted by the wavelength variable interference filter 5 can be expanded.

  On the other hand, a separate adhesive layer may be provided between the fixed reflective film 541 and the reflective film installation surface 512A, or between the movable reflective film 542 and the movable surface 521A. In this case, the number of steps of forming the adhesive layer is increased, but peeling of the fixed reflective film 541 and the movable reflective film 542 when an electrostatic attractive force is generated between the fixed reflective film 541 and the movable reflective film 542 can be prevented.

  In addition, a dielectric multilayer film may be used as the fixed reflective film 541 and the movable reflective film 542. In this case, a conductive film is formed on the lowermost layer of the dielectric multilayer film or the uppermost layer of the dielectric multilayer film. Thus, the first electrostatic actuator 54 can be configured. In this case, by using a highly reflective film such as an Ag alloy as the conductive film, the wavelength range to be measured can be widened, and light having the target wavelength can be extracted with high resolution.

  In the present embodiment, the voltage control unit 15 includes a bias drive unit 151, a gap detector 152, a feedback control unit 153, and a microcomputer 154. The microcomputer 154 outputs a bias signal to the bias driver 151 based on the control signal (target wavelength) input from the controller 20, and outputs a target detection signal corresponding to the target wavelength to the feedback controller 153. . The bias driving unit 151 applies a bias voltage to the first electrostatic actuator 54 to move the movable unit 521 to the vicinity of the target displacement amount. Further, the feedback control unit 153 applies a feedback voltage to the second electrostatic actuator 55 so that the deviation between the detection signal from the gap detector 152 and the target detection signal becomes “0”.

With such a configuration, the sensitivity of the second electrostatic actuator 55 can be reduced during feedback control. Therefore, when the feedback control unit 153 has an analog controller, the gap amount with high accuracy by feedback control is applied to a wide gap range of the gap G1 between the reflection films while the gain of the analog controller is fixed to a constant gain. Can be fine-tuned. In addition, an analog controller having a variable gain that requires a complicated system configuration is not necessary as the feedback control unit 153, and the configuration can be simplified and the cost can be reduced.
Further, even if the feedback control unit 153 is configured to apply a digital voltage to the second electrostatic actuator, the number of bits in the D / A converter can be reduced, so that the cost can be reduced.

In the present embodiment, the microcomputer 154 calculates a bias voltage based on the above equation (1), and outputs a bias signal to the bias driver 151. Therefore, for example, a more accurate bias voltage can be set as compared with the case where the bias voltage with respect to the target gap amount of the inter-reflective film gap G1 is stored as table data, and a large-capacity storage for holding data is possible. Since no area is required, the cost can be reduced.
Further, by performing the bias voltage application step with the bias voltage calculated by the equation (1), the sensitivity of the second electrostatic actuator 55 during the feedback control is made constant regardless of the gap amount of the inter-reflection film gap G1. can do. Thereby, gap control with higher accuracy can be performed.

In the variable wavelength interference filter 5 of the present embodiment, the fixed reflective film 541 and the movable reflective film 542 also function as capacitance detection electrodes. Therefore, it is not necessary to separately provide an electrode with a capacitance detection amount, and the configuration can be simplified.
Note that the first electrode 551 and the second electrode 552 may be used as the capacitance detection electrodes. Even in this case, the configuration can be simplified.

[Second Embodiment]
Next, the optical filter device according to the second embodiment of the present invention will be described below.
In the spectroscopic measurement device 1 of the first embodiment, the wavelength variable interference filter 5 is directly provided to the optical module 10. However, some optical modules have a complicated configuration, and it may be difficult to directly provide the variable wavelength interference filter 5 particularly for a miniaturized optical module. In the present embodiment, an optical filter device that enables the wavelength variable interference filter 5 to be easily installed even for such an optical module will be described below.
FIG. 10 is a cross-sectional view showing a schematic configuration of the optical filter device according to the second embodiment of the present invention.

As shown in FIG. 10, the optical filter device 600 includes a wavelength tunable interference filter 5 and a housing 601 that houses the wavelength tunable interference filter 5.
The housing 601 includes a base substrate 610, a lid 620, a base side glass substrate 630, and a lid side glass substrate 640.

  The base substrate 610 is configured by, for example, a single layer ceramic substrate. On the base substrate 610, the movable substrate 52 of the variable wavelength interference filter 5 is installed. As the installation of the movable substrate 52 on the base substrate 610, for example, it may be disposed via an adhesive layer or the like, and is disposed by being fitted to another fixing member or the like. Also good. In addition, a light passage hole 611 is formed in the base substrate 610 in a region facing the reflective films 541 and 542. And the base side glass substrate 630 is joined so that this light passage hole 611 may be covered. As a method for joining the base side glass substrate 630, for example, glass frit joining using a glass frit that is a piece of glass that has been melted at a high temperature and rapidly cooled, adhesion by an epoxy resin, or the like can be used.

On the base inner surface 612 of the base substrate 610 facing the lid 620, inner terminal portions 615 are provided corresponding to the respective extraction electrodes 543A, 543B, 544A, 544B, 553, and 554 of the wavelength variable interference filter 5. ing. For example, FPC 615A can be used for the connection between each extraction electrode 543A, 543B, 544A, 544B, 553, 554 and the inner terminal portion 615. For example, Ag paste, ACF (Anisotropic Conductive Film), ACP (Anisotropic Conductive Paste) can be used. ) Etc. In addition, when maintaining the internal space 650 in a vacuum state, it is preferable to use Ag paste with little outgas. Further, the connection is not limited to the connection by the FPC 615A, and wiring connection by wire bonding or the like may be performed, for example.
In addition, the base substrate 610 has through holes 614 corresponding to positions where the respective inner terminal portions 615 are provided, and the respective inner terminal portions 615 are interposed via conductive members filled in the through holes 614. The base substrate 610 is connected to an outer terminal portion 616 provided on the base outer surface 613 opposite to the base inner surface 612.
A base joint 617 that is joined to the lid 620 is provided on the outer periphery of the base substrate 610.

As shown in FIG. 10, the lid 620 includes a lid joint 624 joined to the base joint 617 of the base substrate 610, a side wall 625 that continues from the lid joint 624 and rises in a direction away from the base substrate 610, A top surface portion 626 that is continuous from the side wall portion 625 and covers the fixed substrate 51 side of the variable wavelength interference filter 5 is provided. The lid 620 can be formed of an alloy such as Kovar or a metal, for example.
The lid 620 is tightly bonded to the base substrate 610 by bonding the lid bonding portion 624 and the base bonding portion 617 of the base substrate 610.
As this joining method, for example, in addition to laser welding, soldering using silver brazing, sealing using a eutectic alloy layer, welding using low melting glass, glass adhesion, glass frit bonding, epoxy resin Adhesion etc. are mentioned. These bonding methods can be appropriately selected depending on the materials of the base substrate 610 and the lid 620, the bonding environment, and the like.

  The top surface portion 626 of the lid 620 is parallel to the base substrate 610. In the top surface portion 626, a light passage hole 621 is formed in a region facing the reflective films 541 and 542 of the wavelength variable interference filter 5. And the lid side glass substrate 640 is joined so that this light passage hole 621 may be covered. As a method for bonding the lid-side glass substrate 640, for example, glass frit bonding, adhesion using an epoxy resin, or the like can be used as in the case of bonding the base-side glass substrate 630.

[Effects of Second Embodiment]
In the optical filter device 600 of the present embodiment, since the wavelength tunable interference filter 5 is protected by the housing 601, it is possible to prevent changes in the characteristics of the wavelength tunable interference filter 5 due to foreign matters, gases contained in the atmosphere, and the like. It is possible to prevent the wavelength tunable interference filter 5 from being damaged due to mechanical factors. In addition, since intrusion of charged particles can be prevented, charging of the fixed reflective film 541, the movable reflective film 542, the first electrode 551, and the second electrode 552 can be prevented. Therefore, the generation of Coulomb force due to charging can be suppressed, and the parallelism of the reflective films 541 and 542 can be more reliably maintained.

For example, when the wavelength tunable interference filter 5 manufactured in a factory is transported to an assembly line for assembling an optical module or an electronic device, the wavelength tunable interference filter 5 protected by the optical filter device 600 is transported safely. It becomes possible.
In addition, since the optical filter device 600 is provided with the outer terminal portion 616 exposed on the outer peripheral surface of the housing 601, wiring can be easily performed even when the optical filter device 600 is incorporated into an optical module or an electronic device. Become.

  Further, similarly to the first embodiment, the wavelength tunable interference filter 5 is a highly accurate gap control of the gap G1 between the reflection films by the first electrostatic actuator 54 and the second electrostatic actuator 55, and simplification of the electrode shape. It is possible to achieve both downsizing. Therefore, the housing 601 that houses the wavelength variable interference filter 5 can also be formed in a size corresponding to the reduced wavelength variable interference filter 5, and the optical filter device 600 can be reduced in size.

[Other Embodiments]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

In the first embodiment, a bias voltage with constant sensitivity during feedback control is calculated based on the equation (1) and applied to the first electrostatic actuator 54. However, the present invention is not limited to this. I can't.
For example, in the bias voltage application step, the movable unit 521 may be displaced from the target gap amount to a position that is a predetermined distance set in advance, and then feedback control may be performed. Even in such a configuration, since the inter-electrode gap G2 is larger than the inter-reflection film gap G1, the sensitivity of the second electrostatic actuator 55 at the time of feedback control can be sufficiently reduced.

  Further, the bias voltage is obtained based on the formula (1). For example, table data storing the relationship of the bias voltage with respect to the target gap amount is stored, and the microcomputer 154 sets the bias voltage based on the table data. May be.

  In the first embodiment, the configuration in which the gap G1 between the reflection films is larger than the gap G2 between the electrodes is exemplified. For example, the wavelength range to be measured such as the near infrared light range to the far infrared light range is a long wavelength. In this case, the inter-reflection film gap G1 may be smaller than the inter-electrode gap G2. In this case, as described above, the drive extraction electrodes 543A and 544A are connected to the feedback control unit 153, and the first extraction electrode 553 and the second extraction electrode 554 are connected to the bias drive unit 151, thereby enabling the above-described embodiment. Similarly, it is possible to achieve both power saving in the bias voltage application step and highly accurate gap control during feedback control.

In addition, the gap detection unit has exemplified the configuration in which a detection signal based on the electrostatic capacitance between the fixed reflection film 541 and the movable reflection film 542 is acquired and the gap amount is detected, but is not limited thereto. For example, as described above, the gap amount may be detected based on the capacitance between the first electrode 551 and the second electrode 552.
Further, for example, a configuration may be adopted in which the bending amount of the movable substrate 52 (holding portion 522) is detected by a strain gauge or the like to detect the gap amount of the gap G1 between the reflection films, and for detecting the gap amount outside. It is good also as a structure which provides an optical sensor.

  Moreover, although the spectroscopic measurement apparatus 1 has been exemplified as the electronic apparatus of the present invention in each of the above-described embodiments, the wavelength variable interference filter driving method, the optical module, and the electronic apparatus of the present invention are applied to various other fields. be able to.

For example, as shown in FIG. 11, the electronic apparatus of the present invention can also be applied to a color measuring device for measuring color.
FIG. 11 is a block diagram illustrating an example of a color measurement device 400 including a wavelength variable interference filter.
As shown in FIG. 11, the color measurement device 400 includes a light source device 410 that emits light to the inspection target A, a color measurement sensor 420 (optical module), and a control device 430 that controls the overall operation of the color measurement device 400. With. The color measuring device 400 reflects light emitted from the light source device 410 by the inspection target A, receives the reflected inspection target light by the color measuring sensor 420, and outputs the light from the color measuring sensor 420. This is an apparatus for analyzing and measuring the chromaticity of the inspection target light, that is, the color of the inspection target A based on the detection signal.

  A light source device 410, a light source 411, and a plurality of lenses 412 (only one is shown in FIG. 11) are provided, and for example, reference light (for example, white light) is emitted to the inspection target A. The plurality of lenses 412 may include a collimator lens. In this case, the light source device 410 converts the reference light emitted from the light source 411 into parallel light by the collimator lens and inspects from a projection lens (not shown). Inject toward the subject A. In the present embodiment, the color measuring device 400 including the light source device 410 is illustrated, but the light source device 400 may not be provided when the inspection target A is a light emitting member such as a liquid crystal panel.

  As shown in FIG. 11, the colorimetric sensor 420 varies the wavelength of the wavelength variable interference filter 5, the detector 11 that receives the light transmitted through the wavelength variable interference filter 5, and the wavelength of the light transmitted through the wavelength variable interference filter 5. And a voltage control unit 15. Further, the colorimetric sensor 420 includes an incident optical lens (not shown) that guides the reflected light (inspection target light) reflected by the inspection target A to a position facing the wavelength variable interference filter 5. In the colorimetric sensor 3, the wavelength variable interference filter 5 separates the light having a predetermined wavelength from the inspection target light incident from the incident optical lens, and the detected light is received by the detector 11.

The control device 430 controls the overall operation of the color measurement device 400.
As the control device 430, for example, a general-purpose personal computer, a portable information terminal, a color measurement dedicated computer, or the like can be used. The control device 430 includes a light source control unit 431, a colorimetric sensor control unit 432, a colorimetric processing unit 433, and the like as shown in FIG.
The light source control unit 431 is connected to the light source device 410 and outputs a predetermined control signal to the light source device 410 based on, for example, a user's setting input to emit white light with a predetermined brightness.
The colorimetric sensor control unit 432 is connected to the colorimetric sensor 420, sets the wavelength of light received by the colorimetric sensor 420 based on, for example, a user's setting input, and detects the amount of light received at this wavelength. A control signal to this effect is output to the colorimetric sensor 420. Thereby, the voltage control unit 15 of the colorimetric sensor 420 applies a voltage to the electrostatic actuator 56 based on the control signal, and drives the wavelength variable interference filter 5.
The colorimetric processing unit 433 analyzes the chromaticity of the inspection target A from the amount of received light detected by the detector 11.

Another example of the electronic device of the present invention is a light-based system for detecting the presence of a specific substance. As such a system, for example, an in-vehicle gas leak detector that detects a specific gas with high sensitivity by adopting a spectroscopic measurement method using the variable wavelength interference filter of the present invention, or a photoacoustic rare gas detection for a breath test. A gas detection device such as a vessel can be exemplified.
An example of such a gas detection device will be described below with reference to the drawings.

FIG. 12 is a schematic diagram illustrating an example of a gas detection device including a wavelength variable interference filter.
FIG. 13 is a block diagram showing a configuration of a control system of the gas detection device of FIG.
As shown in FIG. 12, the gas detection device 100 includes a sensor chip 110, a flow path 120 including a suction port 120A, a suction flow path 120B, a discharge flow path 120C, and a discharge port 120D, a main body 130, It is configured with.
The main body unit 130 includes a sensor unit cover 131 having an opening through which the flow channel 120 can be attached, a discharge unit 133, a housing 134, an optical unit 135, a filter 136, a wavelength variable interference filter 5, a light receiving element 137 (detection unit), and the like. , A control unit 138 (processing unit) that processes a detected signal and controls the detection unit, a power supply unit 139 that supplies power, and the like. The optical unit 135 emits light, and a beam splitter 135B that reflects light incident from the light source 135A toward the sensor chip 110 and transmits light incident from the sensor chip toward the light receiving element 137. And lenses 135C, 135D, and 135E.
As shown in FIG. 13, an operation panel 140, a display unit 141, a connection unit 142 for interface with the outside, and a power supply unit 139 are provided on the surface of the gas detection device 100. When the power supply unit 139 is a secondary battery, a connection unit 143 for charging may be provided.
Further, as shown in FIG. 13, the control unit 138 of the gas detection device 100 controls a signal processing unit 144 configured by a CPU or the like, a light source driver circuit 145 for controlling the light source 135A, and the variable wavelength interference filter 5. Voltage control unit 146, a light receiving circuit 147 that receives a signal from the light receiving element 137, a sensor chip detection that reads a code of the sensor chip 110 and receives a signal from a sensor chip detector 148 that detects the presence or absence of the sensor chip 110 A circuit 149, a discharge driver circuit 150 for controlling the discharge means 133, and the like are provided.

Next, operation | movement of the above gas detection apparatuses 100 is demonstrated below.
A sensor chip detector 148 is provided inside the sensor unit cover 131 at the upper part of the main body unit 130, and the sensor chip detector 148 detects the presence or absence of the sensor chip 110. When the signal processing unit 144 detects the detection signal from the sensor chip detector 148, the signal processing unit 144 determines that the sensor chip 110 is attached, and displays a display signal for displaying on the display unit 141 that the detection operation can be performed. put out.

  For example, when the operation panel 140 is operated by the user and an instruction signal to start the detection process is output from the operation panel 140 to the signal processing unit 144, the signal processing unit 144 first sends the signal processing unit 144 to the light source driver circuit 145. A light source activation signal is output to activate the light source 135A. When the light source 135A is driven, laser light having a single wavelength and stable linear polarization is emitted from the light source 135A. The light source 135A includes a temperature sensor and a light amount sensor, and the information is output to the signal processing unit 144. When the signal processing unit 144 determines that the light source 135A is stably operating based on the temperature and light quantity input from the light source 135A, the signal processing unit 144 controls the discharge driver circuit 150 to operate the discharge unit 133. Thereby, the gas sample containing the target substance (gas molecule) to be detected is guided from the suction port 120A to the suction channel 120B, the sensor chip 110, the discharge channel 120C, and the discharge port 120D. The suction port 120A is provided with a dust removal filter 120A1 to remove relatively large dust, some water vapor, and the like.

The sensor chip 110 is a sensor that incorporates a plurality of metal nanostructures and uses localized surface plasmon resonance. In such a sensor chip 110, an enhanced electric field is formed between the metal nanostructures by the laser light, and when gas molecules enter the enhanced electric field, Raman scattered light and Rayleigh scattered light including information on molecular vibrations are generated. Occur.
These Rayleigh scattered light and Raman scattered light enter the filter 136 through the optical unit 135, and the Rayleigh scattered light is separated by the filter 136, and the Raman scattered light enters the wavelength variable interference filter 5. Then, the signal processing unit 144 outputs a control signal to the voltage control unit 146. Thus, as shown in the first embodiment, the voltage control unit 146 includes the bias drive unit 151, the gap detector 152, the feedback control unit 153, and the microcomputer 154. The drive method is the same as that of the first embodiment. Thus, the wavelength variable interference filter 5 is driven, and the Raman scattered light corresponding to the gas molecule to be detected is dispersed by the wavelength variable interference filter 5. Thereafter, when the dispersed light is received by the light receiving element 137, a light reception signal corresponding to the amount of received light is output to the signal processing unit 144 via the light receiving circuit 147. In this case, target Raman scattered light can be extracted from the wavelength variable interference filter 5 with high accuracy.
The signal processing unit 144 compares the spectrum data of the Raman scattered light corresponding to the gas molecule to be detected obtained as described above and the data stored in the ROM, and determines whether or not the target gas molecule is the target gas molecule. To determine the substance. Further, the signal processing unit 144 displays the result information on the display unit 141 or outputs the result information from the connection unit 142 to the outside.

  12 and 13 exemplify the gas detection device 100 that performs gas detection from the Raman scattered light obtained by spectrally dividing the Raman scattered light by the wavelength variable interference filter 5. You may use as a gas detection apparatus which specifies gas classification by detecting the light absorbency of. In this case, a gas sensor that allows gas to flow into the sensor and detects light absorbed by the gas in the incident light is used as the optical module of the present invention. A gas detection device that analyzes and discriminates the gas flowing into the sensor by such a gas sensor is an electronic apparatus of the present invention. Even in such a configuration, it is possible to detect a gas component using the wavelength variable interference filter.

In addition, the system for detecting the presence of a specific substance is not limited to the detection of the gas as described above, but a non-invasive measuring device for saccharides by near-infrared spectroscopy, and non-invasive information on food, living body, minerals, etc. A substance component analyzer such as a measuring device can be exemplified.
Hereinafter, a food analyzer will be described as an example of the substance component analyzer.

FIG. 14 is a diagram illustrating a schematic configuration of a food analyzer that is an example of an electronic apparatus using the wavelength variable interference filter 5.
As shown in FIG. 14, the food analyzer 200 includes a detector 210 (optical module), a control unit 220, and a display unit 230. The detector 210 includes a light source 211 that emits light, an imaging lens 212 into which light from the measurement target is introduced, a wavelength variable interference filter 5 that splits the light introduced from the imaging lens 212, and the dispersed light. And an imaging unit 213 (detection unit) for detecting.
In addition, the control unit 220 controls the light source control unit 221 that controls the turning on / off of the light source 211 and the brightness control at the time of lighting, the voltage control unit 222 that controls the wavelength variable interference filter 5, and the imaging unit 213. , A detection control unit 223 that acquires a spectral image captured by the imaging unit 213, a signal processing unit 224, and a storage unit 225.

  In the food analyzer 200, when the system is driven, the light source 211 is controlled by the light source control unit 221, and light is irradiated from the light source 211 to the measurement object. Then, the light reflected by the measurement object enters the wavelength variable interference filter 5 through the imaging lens 212. The wavelength variable interference filter 5 is driven by the driving method as shown in the first embodiment under the control of the voltage control unit 222. Thereby, the light of the target wavelength can be extracted from the variable wavelength interference filter 5 with high accuracy. Then, the extracted light is imaged by an imaging unit 213 configured by, for example, a CCD camera or the like. The captured light is accumulated in the storage unit 225 as a spectral image. In addition, the signal processing unit 224 controls the voltage control unit 222 to change the voltage value applied to the wavelength tunable interference filter 5, and acquires a spectral image for each wavelength.

Then, the signal processing unit 224 performs arithmetic processing on the data of each pixel in each image accumulated in the storage unit 225, and obtains a spectrum at each pixel. In addition, the storage unit 225 stores, for example, information related to food components with respect to the spectrum, and the signal processing unit 224 analyzes the obtained spectrum data based on the information related to food stored in the storage unit 225. The food component contained in the detection target and its content are obtained. Moreover, a food calorie, a freshness, etc. are computable from the obtained food component and content. Furthermore, by analyzing the spectral distribution in the image, it is possible to extract a portion of the food to be inspected that has reduced freshness, and to detect foreign substances contained in the food. Can also be implemented.
Then, the signal processing unit 224 performs processing for causing the display unit 230 to display information such as the components and contents of the food to be examined, the calories, and the freshness obtained as described above.

Moreover, although the example of the food analyzer 200 is shown in FIG. 14, it can utilize also as a non-invasive measuring apparatus of the other information as mentioned above by substantially the same structure. For example, it can be used as a biological analyzer for analyzing biological components such as measurement and analysis of body fluid components such as blood. As such a bioanalytical device, for example, a device that detects ethyl alcohol as a device that measures a body fluid component such as blood, it can be used as a drunk driving prevention device that detects the drunk state of the driver. Further, it can also be used as an electronic endoscope system provided with such a biological analyzer.
Furthermore, it can also be used as a mineral analyzer for performing component analysis of minerals.

Furthermore, the variable wavelength interference filter, optical module, and electronic apparatus of the present invention can be applied to the following devices.
For example, it is possible to transmit data using light of each wavelength by changing the intensity of light of each wavelength over time. In this case, light of a specific wavelength is transmitted by a wavelength variable interference filter provided in the optical module. The data transmitted by the light of the specific wavelength can be extracted by separating the light and receiving the light at the light receiving unit, and the electronic data having such a data extraction optical module can be used to extract the light data of each wavelength. By processing, optical communication can be performed.

Further, the electronic apparatus can be applied to a spectroscopic camera, a spectroscopic analyzer, or the like that captures a spectroscopic image by dispersing light with the variable wavelength interference filter of the present invention. An example of such a spectroscopic camera is an infrared camera incorporating a wavelength variable interference filter.
FIG. 15 is a schematic diagram showing a schematic configuration of the spectroscopic camera. As shown in FIG. 15, the spectroscopic camera 300 includes a camera body 310, an imaging lens unit 320, and an imaging unit 330 (detection unit).
The camera body 310 is a part that is gripped and operated by a user.
The imaging lens unit 320 is provided in the camera body 310 and guides incident image light to the imaging unit 330. As shown in FIG. 15, the imaging lens unit 320 includes an objective lens 321, an imaging lens 322, and a variable wavelength interference filter 5 provided between these lenses.
The imaging unit 330 includes a light receiving element, and images the image light guided by the imaging lens unit 320.
In such a spectroscopic camera 300, a spectral image of light having a desired wavelength can be captured by transmitting light having a wavelength to be imaged by the variable wavelength interference filter 5. At this time, for each wavelength, a voltage controller (not shown) drives the wavelength variable interference filter 5 by the driving method of the present invention as shown in the first embodiment, so that a spectral image of the target wavelength can be accurately obtained. Image light can be extracted.

Furthermore, the wavelength tunable interference filter of the present invention may be used as a bandpass filter. For example, only light in a narrow band centered on a predetermined wavelength is tunable out of light in a predetermined wavelength range emitted from a light emitting element. It can also be used as an optical laser device that spectrally transmits through an interference filter.
In addition, the tunable interference filter of the present invention may be used as a biometric authentication device, and can be applied to authentication devices such as blood vessels, fingerprints, retinas, and irises using light in the near infrared region and visible region.

  Furthermore, an optical module and an electronic device can be used as a concentration detection device. In this case, the infrared energy (infrared light) emitted from the substance is spectrally analyzed by the variable wavelength interference filter, and the analyte concentration in the sample is measured.

  As described above, the tunable interference filter, the optical module, and the electronic device of the present invention can be applied to any device that splits predetermined light from incident light. Since the wavelength tunable interference filter according to the present invention can split a plurality of wavelengths with one device as described above, it is possible to accurately measure a spectrum of a plurality of wavelengths and detect a plurality of components. it can. Therefore, compared with the conventional apparatus which takes out a desired wavelength with a plurality of devices, it is possible to promote downsizing of the optical module and the electronic apparatus, and for example, it can be suitably used as a portable or in-vehicle optical device.

  In addition, the specific structure for carrying out the present invention can be appropriately changed to other structures and the like within a range in which the object of the present invention can be achieved.

  DESCRIPTION OF SYMBOLS 1 ... Spectrometer, 5 ... Variable wavelength interference filter, 10 ... Optical module, 15 ... Voltage control part, 20 ... Control part, 51 ... Fixed board | substrate (1st board | substrate), 52 ... Movable board | substrate (2nd board | substrate), 54 DESCRIPTION OF SYMBOLS ... 1st electrostatic actuator, 55 ... 2nd electrostatic actuator, 100 ... Gas detection apparatus (electronic device), 137 ... Light receiving element (detection part), 151 ... Bias drive part (bias voltage application means), 152 ... Gap detection 153 ... Feedback control unit (feedback voltage applying unit), 154 ... Microcomputer, 200 ... Food analysis device (electronic device), 213 ... Imaging unit (detection unit), 300 ... Spectral camera (electronic device) , 330: Imaging unit (detection unit), 400: Color measuring device (electronic device), 430 ... Control unit, 521 ... Movable unit, 522 ... Holding unit, 541 ... Fixed reflection film First reflective film), 542 ... Movable reflective film (second reflective film), 551 ... First electrode, 552 ... Second electrode, 600 ... Optical filter device, 601 ... Housing, G1 ... Gap between reflective films, G2 ... Interelectrode gap.

Claims (11)

A first substrate;
A second substrate disposed opposite the first substrate;
A conductive first reflective film provided on the first substrate;
A conductive second reflective film provided on the second substrate and disposed opposite to the first reflective film via a gap between the reflective films;
A first electrode provided on the first substrate;
A second electrode provided on the second substrate and disposed opposite to the first electrode via an inter-electrode gap; and
The first reflective film and the second reflective film constitute a first electrostatic actuator that changes a gap amount of the gap between the reflective films,
The variable wavelength interference filter according to claim 1, wherein the first electrode and the second electrode constitute a second electrostatic actuator that changes a gap amount of the gap between the reflection films. The tunable interference filter according to claim 1,
The wavelength tunable interference filter, wherein the gap between the reflective films and the gap between the electrodes have different gap amounts. The tunable interference filter according to claim 2,
The wavelength tunable interference filter, wherein the gap between the reflection films is smaller than the gap between the electrodes. In the wavelength variable interference filter according to any one of claims 1 to 3,
The variable wavelength interference filter, wherein the first reflective film and the second reflective film are made of a metal alloy film. In the wavelength variable interference filter according to any one of claims 1 to 3,
The variable wavelength interference filter according to claim 1, wherein the first reflective film and the second reflective film are configured by a laminate of a dielectric multilayer film and a conductive film. A first substrate, a second substrate disposed opposite to the first substrate, a conductive first reflective film provided on the first substrate, provided on the second substrate, with respect to the first reflective film A conductive second reflective film disposed opposite to the reflective film with a gap between the reflective films, a first electrode provided on the first substrate, and a second electrode provided on the second substrate, A wavelength tunable interference filter comprising a second electrode disposed oppositely through a gap between the electrodes;
A housing that houses the wavelength tunable interference filter;
The first reflective film and the second reflective film constitute a first electrostatic actuator that changes a gap amount of the gap between the reflective films,
An optical filter device, wherein the first electrode and the second electrode constitute a second electrostatic actuator that changes a gap amount of the gap between the reflective films. A first substrate;
A second substrate disposed opposite the first substrate;
A conductive first reflective film provided on the first substrate;
A conductive second reflective film provided on the second substrate and disposed opposite to the first reflective film via a gap between the reflective films;
A first electrode provided on the first substrate;
A second electrode provided on the second substrate and disposed opposite to the first electrode via an inter-electrode gap;
A voltage controller;
Comprising
The first reflective film and the second reflective film constitute a first electrostatic actuator that changes a gap amount of the gap between the reflective films,
The first electrode and the second electrode constitute a second electrostatic actuator that changes a gap amount of the gap between the reflective films,
The voltage control unit applies independent voltages to the first electrostatic actuator and the second electrostatic actuator, respectively. The optical module according to claim 7, wherein
The voltage controller is
Bias voltage applying means for applying a preset bias voltage to any one of the first electrostatic actuator and the second electrostatic actuator;
Gap detecting means for detecting a gap amount of the gap between the reflective films;
Feedback voltage application for applying a feedback voltage corresponding to the gap amount detected by the gap detection means to the other one of the first electrostatic actuator and the second electrostatic actuator to which the bias voltage is not applied. Means,
An optical module comprising: The optical module according to claim 8, wherein
The gap between the reflection films between the first reflection film and the second reflection film constituting the first electrostatic actuator, and between the first electrode and the second electrode constituting the second electrostatic actuator. And the gap between the electrodes has a different gap amount,
The bias voltage applying unit applies the bias voltage to one of the first electrostatic actuator and the second electrostatic actuator having a small gap amount;
The optical feedback module, wherein the feedback voltage applying means applies the feedback voltage to the other one of the first electrostatic actuator and the second electrostatic actuator having the larger gap amount. A first substrate;
A second substrate disposed opposite the first substrate;
A conductive first reflective film provided on the first substrate;
A conductive second reflective film provided on the second substrate and disposed opposite to the first reflective film via a gap between the reflective films;
A first electrode provided on the first substrate;
A second electrode provided on the second substrate and disposed opposite to the first electrode via an inter-electrode gap;
A detection unit for detecting light extracted by the first reflective film and the second reflective film;
The first reflective film and the second reflective film constitute a first electrostatic actuator that changes a gap amount of the gap between the reflective films,
An electronic apparatus, wherein the first electrode and the second electrode constitute a second electrostatic actuator that changes a gap amount of the gap between the reflective films. A first substrate, a second substrate disposed opposite to the first substrate, a conductive first reflective film provided on the first substrate, provided on the second substrate, with respect to the first reflective film A conductive second reflective film disposed oppositely through the gap between the reflective films, a first electrode provided on the first substrate, and a second electrode provided on the second substrate, A first electrostatic actuator comprising a second electrode arranged opposite to the gap between the electrodes, and changing the gap amount of the gap between the reflection films by the first reflection film and the second reflection film Comprising: a second electrostatic actuator configured to change a gap amount of the gap between the reflection films by the first electrode and the second electrode.
A bias voltage applying step of applying a preset bias voltage to any one of the first electrostatic actuator and the second electrostatic actuator;
A gap detection step of detecting a gap amount of the gap between the reflection films;
Feedback voltage application for applying a feedback voltage corresponding to the gap amount detected by the gap detection means to the other one of the first electrostatic actuator and the second electrostatic actuator to which the bias voltage is not applied. Steps,
A method for driving a wavelength tunable interference filter, characterized in that:

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