JP2020101820A - Driving device and optical filter - Google Patents

Abstract

To provide a driving device in which a movable unit can be operated with high accuracy, and an optical filter in which an interval between reflection films can be adjusted with high accuracy.SOLUTION: The driving device includes: first and second substrates 11A and 11B that have first and second principal surfaces opposing each other with a gap, respectively; a movable part 12 of which the bottom surface constitutes the first principal surface, and which moves in a direction perpendicular to the first principal surface; a support part 13 that movably supports the movable part with respect to the first substrate; and first and second driving electrodes 14A and 14B that are formed on the movable part and the second principal surface, respectively, and give, by being applied with voltage, the movable part electrostatic force having a first component of the movement direction of the movable part and a second component of a direction perpendicular to the movement direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a driving device and a wavelength tunable optical filter including the driving device.

The optical filter is, for example, an optical element configured to selectively emit only light having a predetermined wavelength (wavelength band) from the incident light. For example, a wavelength selection element such as an optical filter has a configuration in which a pair of reflective films facing each other are arranged. The pair of reflective films are arranged, for example, in parallel with a gap. Further, the distance between the reflection films is set according to the wavelength of the light to be extracted.

For example, in Patent Document 1, a fixed reflective film provided on a fixed substrate, a movable reflective film provided on a movable substrate, a first electrode provided on the fixed substrate, and an inter-electrode gap provided on the movable substrate. There is disclosed a wavelength tunable interference filter including a second electrode arranged so as to face the first electrode via the.

JP 2013-218194 JP

In general, the optical filter is classified into a fixed wavelength type in which the distance (optical gap) between the reflection films is fixed and a variable wavelength type in which the optical gap can be adjusted. The wavelength tunable optical filter includes, for example, one fixed reflection film and the other reflection film that faces the one reflection film with a gap and is movable in the film thickness direction. In this wavelength tunable optical filter, it is preferable that the distance between the reflection films can be adjusted with high accuracy.

In addition, it is preferable not only to displace the reflective film in the optical filter, but also to be able to operate the movable portion with high accuracy, for example, in a driving device having the movable portion.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a drive device capable of accurately operating a movable portion. Another object of the present invention is to provide an optical filter capable of accurately adjusting the distance between reflection films.

According to a first aspect of the present invention, there is provided a drive device, which includes first and second substrates having first and second main surfaces facing each other with a gap, and a first main surface formed on the first main surface. A movable part that moves in a direction perpendicular to the main surface, a support part that movably supports the movable part with respect to the first substrate, and a support part that is formed on the first and second main surfaces, respectively, A first and a second drive electrode for applying an electrostatic force having a first component in the moving direction of the movable part and a second component in the direction perpendicular to the moving direction to the movable part, There is.

An optical filter according to a tenth aspect of the present invention includes the drive device, and first and second reflective films that are arranged to face each other on the movable portion and the second main surface. Is characterized by.

(A) is a schematic top view of the drive device according to the first embodiment, and (b) is a cross-sectional view of the drive device according to the first embodiment. FIG. 6A is a sectional view showing a structure of an electrode portion of the driving device according to the first embodiment, and FIG. 7B is a sectional view showing a state during operation of the driving device according to the first embodiment. (A) is a figure which shows the relationship of the moving amount of the movable part with respect to the drive voltage of the drive device which concerns on Example 1 and a comparative example. (A) And (b) is sectional drawing of the drive device which concerns on the modification 1 and modification 2 of Example 1, respectively. (A) And (b) is sectional drawing of the drive device which concerns on Example 2 and its modification, respectively. (A) is a schematic top view of the drive device according to the third embodiment, and (b) is a cross-sectional view of the drive device according to the third embodiment. (A) is a schematic top view of the optical filter according to Example 4, and (b) is a cross-sectional view of the optical filter according to Example 4. FIG. 8 is an operation explanatory diagram of the optical filter according to the fourth embodiment.

Examples of the present invention will be described in detail below.

FIG. 1A is a diagram schematically illustrating the upper surface of the drive device 10 according to the first embodiment. FIG. 1B is a cross-sectional view taken along the line VV of FIG. The drive device 10 has first and second substrates 11A and 11B having first and second main surfaces PL1 and PL2 facing each other with a gap GP therebetween. Hereinafter, the first and second substrates 11A and 11B may be referred to as a substrate pair 11. Further, the first and second main surfaces PL1 and PL2 may be referred to as a main surface pair PP.

In this embodiment, as shown in FIG. 1A, the first and second substrates 11A and 11B have a rectangular outer shape. The first and second substrates 11A and 11B have a flat plate shape. Further, first main surface PL1 is formed of one central portion of the main surface of first substrate 11A. Further, in the present embodiment, a columnar recess is provided on one of the main surfaces of the second substrate 11B, and the bottom surface of the recess is the second main surface PL2. In this embodiment, the first and second main surfaces PL1 and PL2 are arranged parallel to each other.

Drive device 10 has a movable portion 12 whose bottom surface constitutes first main surface PL1 and moves in direction D perpendicular to first main surface PL1. In the present embodiment, as shown in FIG. 1A, the movable portion 12 has a rotationally symmetrical shape with respect to the moving direction D of the movable portion 12. More specifically, for example, in the present embodiment, the movable portion 12 has a columnar shape whose center axis is a rotational symmetry axis C along the moving direction D of the movable portion 12.

The drive device 10 has a support portion 13 that movably supports the movable portion 12 with respect to the first substrate 11A. Specifically, for example, the support portion 13 has an annular shape formed on the first substrate 11A and surrounding the movable portion 12. In this embodiment, as shown in FIG. 1B, the supporting portion 13 is composed of the thin film portion of the first substrate 11A provided around the movable portion 12.

More specifically, a ring-shaped groove is provided on the main surface of the first substrate 11A opposite to the first main surface PL1, and the support portion 13 is provided with the first substrate 11A. Is a relatively thin part of. Then, the inner portion of the support portion 13 on the first substrate 11A functions as the movable portion 12. Therefore, the bottom surfaces of the movable portion 12 and the support portion 13 form the first main surface PL1. In addition, in this embodiment, the support portion 13 has an annular shape that is coaxial with the rotational symmetry axis C of the movable portion 12.

The drive device 10 includes a drive unit 14 formed on the first and second main surfaces PL1 and PL2, respectively, which includes first and second drive electrodes 14A and 14B that generate an electrostatic force that moves the movable unit 12. Have. In this embodiment, the first and second drive electrodes 14A and 14B
Are arranged along the outer peripheral portion of the movable portion 12 when seen through from the moving direction D of the movable portion 12 (direction perpendicular to the first main surface PL1).

In addition, in the present embodiment, the first and second drive electrodes 14A and 14B form the outer edge of the movable portion 12 (that is, the connection portion with the support portion 13) when seen through in the moving direction D of the movable portion 12. It is provided in a ring shape inside. Specifically, first drive electrode 14A is provided in a film shape along the outer peripheral portion of movable portion 12 on first main surface PL1. Further, second drive electrode 14B is provided in a film shape on second main surface PL2 so as to face first drive electrode 14A.

Further, as shown in FIG. 1B, the first and second drive electrodes 14A and 14B are arranged offset from each other in a direction perpendicular to the moving direction D of the movable portion 12. In this embodiment, the first and second drive electrodes 14A and 14B have an annular shape that is coaxial with the rotational symmetry axis C of the movable portion 12. Further, the first and second drive electrodes 14A and 14B have similar shapes centering on the rotational symmetry axis C. Further, in this embodiment, the similarity ratio of the first and second drive electrodes 14A and 14B is not 1:1.

In other words, the first and second drive electrodes 14A and 14B are coaxially arranged in a top view, but are formed at positions and sizes displaced from each other. Further, in the present embodiment, the first drive electrode 14A is formed slightly outside the second drive electrode 14B in a top view. That is, in the in-plane direction of the first main surface PL1, the distance from the rotational symmetry axis C of the movable part 12 to the first drive electrode 14A is from the rotational symmetry axis C of the movable part 12 to the second drive electrode 14B. Greater than the distance.

The drive unit 14 generates an electrostatic force by applying a voltage from a power source (not shown) to the first and second drive electrodes 14A and 14B. The movable portion 12 moves in the direction D perpendicular to the first main surface PL1, that is, in the height direction of the gap GP by this electrostatic force. The drive device 10 is a device that moves the movable part 12 by the drive part 14 and drives an object according to the movement of the movable part 12.

In addition, as shown in FIGS. 1A and 1B, the driving device 10 has a structure in which the first and second substrates 11</b>A and 11</b>B are bonded to each other by the bonding portion 15. In the present embodiment, the bonding portion 15 is provided in the peripheral area (outer area of the movable portion 12 and the support portion 13) of the first and second substrates 11A and 11B.

FIG. 2A is a partially enlarged sectional view showing the movable portion 12, the support portion 13, and the drive portion 14 in an enlarged manner. FIG. 2A is an enlarged view of a portion surrounded by a broken line in FIG. In addition, FIG. 2A is a diagram showing a state in which no voltage is applied to the drive unit 14. In the drive device 10, the electrostatic force is not generated in the state where the voltage is not applied to the drive unit 14, and the movable unit 12 does not move. The position of the movable portion 12 in this state is used as a reference position. Further, the height of the gap GP between the first and second main surfaces PL1 and PL2 at the reference position is height GP0.

As shown in FIG. 2A, the drive unit 14 has a configuration in which the first and second drive electrodes 14A and 14B are formed at positions offset from each other. In the present embodiment, the first and second drive electrodes 14A and 14B have regions 14A1 and 14B1 that overlap each other when seen in the moving direction D of the movable portion 12. Specifically, the first and second drive electrodes 14A and 14B have facing regions 14A1 and 14B1 facing each other and non-facing regions 14A2 and 14B2 not facing each other.

Further, in the present embodiment, as shown in FIG. 2A, the facing region (first facing region) 14A1 of the first drive electrode 14A is made up of the inner portion of the first drive electrode 14A and is not facing. The region (first non-opposing region) 14A2 is composed of the outer portion of the first drive electrode 14A. Further, the facing region (second facing region) 14B1 of the second drive electrode 14B is formed of an outer portion of the second driving electrode 14B, and the non-facing region (second non-facing region) 14B2 is the second drive electrode. It consists of the inner part of 14B.

FIG. 2B is a partially enlarged cross-sectional view showing the movable portion 12, the support portion 13, and the driving portion 14 in an enlarged manner when a voltage is applied to the driving portion 14. First, the outline of the movement operation of the movable portion 12 will be described. When a voltage is applied to the first and second drive electrodes 14A and 14B, for example, an electrostatic attractive force F is generated between the first and second drive electrodes 14A and 14B. The supporting portion 13 is elastically deformed by the electrostatic attraction F and bends (tilts) toward the second substrate 11B. The support portion 13 (thin film portion) is provided around the movable portion 12. Therefore, the entire movable portion 12 moves toward the second substrate 11B. Thereby, for example, the gap GP decreases from the height GP0 to the height GP1. It should be noted that depending on the value of the applied voltage, an electrostatic repulsive force may be generated between the first and second drive electrodes 14A and 14B to move the movable portion 12 in the direction in which the gap GP increases.

Here, the first and second drive electrodes 14A and 14B will be described in detail. As described above, the first and second drive electrodes 14A and 14B are formed at offset positions and do not completely face each other. Since the first and second drive electrodes 14A and 14B have such an arrangement relationship, the electrostatic force F generated between them is the component Fa in the moving direction D of the movable portion 12 and the movable portion 12 of the movable portion 12. It has a component Fb in a direction perpendicular to the moving direction D.

In other words, the first and second drive electrodes 14A and 14B are formed on the first and second main surfaces PL1 and PL2, and the moving direction D of the movable portion 12 with respect to the movable portion 12 is applied by applying a voltage. Is configured to give an electrostatic force F having a component (first component) Fa and a component (second component) Fb in a direction perpendicular to the moving direction D of the movable portion 12.

Of the electrostatic force F generated by the drive unit 14, the component Fa perpendicular to the first main surface PL1 contributes to the movement of the movable unit 12. On the other hand, the component Fb parallel to the first main surface PL1 does not contribute to the movement of the movable portion 12. Therefore, the movable portion 12 does not move largely with respect to the change in the voltage applied to the driving portion 14.

FIG. 3A is a diagram showing the relationship between the voltage applied to the drive unit 14 and the movement amount of the movable unit 12. For comparison with the drive device 10, the drive device 100 according to the comparative example is different from the drive device 10 except that it has drive electrodes E1 and E2 that are completely opposed to each other, as shown in FIG. A drive device having the same configuration as that of 1. was prepared. FIG. 3A is a graph showing the comparison result of the relationship between the applied voltage and the moving amount of the movable portion in both cases. The horizontal axis of FIG. 3A is the voltage value applied to the drive electrode, and the vertical axis is the amount of movement of the movable portion.

As shown in FIG. 3A, in the driving device 100, it is found that when the voltage applied between the driving electrodes E1 and E2 is increased, the change in the moving amount of the movable portion 12 gradually increases. On the other hand, in the drive device 10, it can be seen that the change in the movement amount of the movable portion 12 with respect to the change in the voltage applied to the drive electrodes 14A and 14B is gentle. It can be understood that this is because the drive electrodes 14A and 14B are arranged offset.

Moreover, when the electrostatic force is generated by the film-shaped (plate-shaped) electrodes, the magnitude of the electrostatic force is inversely proportional to the square of the distance between the electrodes. That is, for example, when the distance between the electrodes is halved, the generated electrostatic force is quadrupled. That is, when the electrodes are arranged with a relatively small distance, the distance between the electrodes changes abruptly when the applied voltage is changed.

On the other hand, in this embodiment, the first and second drive electrodes 14A and 14B are arranged offset. Therefore, as described above, part of the electrostatic force F (component Fb) does not contribute to the movement of the movable portion 12, so that the change in the moving force (component Fa) of the movable portion 12 with respect to the change in the applied voltage is gradual. Become. Therefore, the abrupt movement of the movable portion 12 can be suppressed.

Further, in the present embodiment, the component Fb of the generated electrostatic force F in the direction perpendicular to the moving direction D of the movable portion 12 contributes to suppressing the deformation (distortion) during the movement of the movable portion 12. Specifically, when the movable portion 12 is moved by elastic deformation of the support portion 13 as in the present embodiment, the central portion of the movable portion 12 may be deformed so as to bend. This is due to the difference between the stress acting on the outer peripheral portion of the movable portion 12 (that is, near the support portion 13) and the stress acting on the central portion of the movable portion 12 when the drive voltage is applied. Therefore, the entire movable portion 12 may not move accurately.

For example, when the movable portion 12 is moved in the direction toward the second main surface PL2, the central portion of the movable portion 12 may be bent toward the second main surface PL2. On the other hand, in the present embodiment, the component Fb of the electrostatic force F in the direction perpendicular to the direction D is a force that causes the movable portion 12 to expand and contract in the in-plane direction of the first main surface PL1. Act on 12. Therefore, distortion during movement of the movable portion 12 is suppressed, and the entire movable portion 12 can be stably and precisely moved.

FIG. 4A is a cross-sectional view of the drive device 10A according to the first modification of the first embodiment. The drive unit 10A has the same configuration as the drive unit 10 except for the configuration of the drive unit 16. In the present modified example, the drive section 16 has first and second drive electrodes 16A and 16B formed on the first and second main surfaces PL1 and PL2, respectively. In this modification, the first drive electrode 16A is arranged inside the second drive electrode 16B when seen in the moving direction D of the movable portion 12.

As in this modified example, the first drive electrode 16A may be displaced from the second drive electrode 16B closer to the rotational symmetry axis C of the movable portion 12 (drive electrodes 16A and 16B). In this case, the movable portion 12 has a force to move the movable portion 12 in the direction D perpendicular to the first main surface PL1 and a force to pull the movable portion 12 in a direction parallel to the first main surface PL1. An electrostatic force is generated.

FIG. 4B is a cross-sectional view of the drive device 10B according to the second modification of the first embodiment. The drive device 10B has the same configuration as the drive device 10 except for the configuration of the drive unit 17. In the present modification, drive unit 17 has first and second drive electrodes 17A and 17B formed on first and second main surfaces PL1 and PL2, respectively. In the present modification, the first and second drive electrodes 17A and 17B do not have regions that face each other (for example, the facing regions 14A1 and 14B1).

That is, the first and second drive electrodes 17A and 17B are arranged so as not to overlap each other in a top view. In the present modified example, of the generated electrostatic forces, the force that moves the movable portion 12 is relatively small. Therefore, the configuration is useful when it is desired to more precisely control the movement amount of the movable portion 12.

As described above, the driving device 10 (10A or 10B) generates the electrostatic force F having the component Fa in the moving direction D of the movable portion 12 and the component Fb in the direction perpendicular to the moving direction D. Two drive electrodes 14A (16A or 17A) and 14B (16B or 17B) are included.
Therefore, it is possible to provide a drive device capable of operating the movable portion 12 with high accuracy and performing stable driving.

FIG. 5A is a cross-sectional view showing the configuration of the drive device 20 according to the second embodiment. The drive device 20 has the same configuration as the drive device 10 except for the configuration of the drive unit 21. The drive unit 21 has first and second drive electrodes 21A and 21B formed on the first and second main surfaces PL1 and PL2, respectively, and having a different electrode width and formed in an annular shape. Specifically, the wiring width W1 of the first drive electrode 21A, that is, the length in the radial direction (radial direction) about the rotational symmetry axis C of the movable portion 12 is the wiring width W2 of the second drive electrode 21B. Greater than.

In the present embodiment, as shown in FIG. 5A, the first drive electrode 21A has a facing region facing the second driving electrode 21B and a non-facing region provided outside the facing region. Have. On the other hand, the second drive electrode 21B faces the first drive electrode 21A as a whole.

FIG. 5B is a cross-sectional view showing the configuration of the drive device 20A according to the modified example of the second embodiment. 20 A of drive devices have the same structure as the drive device 20 except the structure of the drive part 22. The drive unit 22 has first and second drive electrodes 22A and 22B formed on the first and second main surfaces PL1 and PL2, respectively, and having a different electrode width and formed in an annular shape. In this modification, the wiring width W3 of the first drive electrode 22A, that is, the length in the radial direction around the rotational symmetry axis C of the movable portion 12 is smaller than the wiring width W4 of the second drive electrode 22B. ..

In this modified example, as shown in FIG. 5B, the first drive electrode 22A faces the second drive electrode 22B as a whole. On the other hand, the second drive electrode 22B has a facing region facing the first driving electrode 22A and a non-facing region provided inside the facing region.

Like the drive devices 20 and 20A, drive electrodes 21A (22A) and 21B (22B) having different wiring widths may be provided in consideration of adjustment of components of generated electrostatic force in each direction. .. Also in the drive devices 20 and 20A, the first and second drive electrodes 21A (22A) and 21B (22B) are formed at positions that are offset from each other as a whole.

FIG. 6A is a schematic top view of the drive device 30 according to the third embodiment. FIG. 6B is a cross-sectional view taken along the line WW of FIG. The drive device 30 has the same configuration as the drive device 10 except for the configurations of the drive unit 31 and the detection unit 32. The drive device 30 includes a drive unit 31 that generates an electrostatic force that moves the movable unit 12, and a detection unit 32 that detects a movement amount (position) of the movable unit. The drive unit 31 also includes a plurality of sub-drive units 31P that are independent of each other. Further, the detection unit 32 has at least one sub detection unit 32P that is independent of each other.

Each of the sub-driving unit 31P and the sub-detecting unit 32P is arranged rotationally symmetrically with respect to the rotational symmetry axis C of the movable unit 12. In the present embodiment, the drive unit 31 has four sub-drive units 31P formed in 90-degree rotational symmetry. Further, the detection unit 32 has four sub detection units 32P formed inside the sub drive unit 31P in a 90-degree rotational symmetry.

As shown in FIG. 6B, the sub-driving section 31P is formed on each of the first and second main surfaces PL1 and PL2, and the first and second sub-driving sections 31P generate an electrostatic force that moves the movable section 12. It has sub-driving electrodes 31A and 31B. The first and second sub-driving electrodes 31A and 31B correspond to the case where each of the first and second driving electrodes 14A and 14B in the driving device 10 is composed of four sub-driving electrodes insulated from each other. For example, in this embodiment, the four first sub-driving electrodes 31A are arranged apart from each other.

In the present embodiment, the drive unit 31 is divided into a plurality of sub drive units 31P, and each of the sub drive units 31P moves the movable unit 12 independently of each other. For example, when four sub-driving portions 31P are arranged in an annular shape as in this embodiment, the movable portion 12 can be moved so as to be inclined. Therefore, the movable portion 12 can be moved with a high degree of freedom. For example, when the movable portion 12 is moving unintentionally (for example, tilting) when moving, the movable portion 12 can be corrected (corrected) to have a desired movement mode.

The sub-detection unit 32P has first and second detection electrodes 32A and 32B that are formed on the first and second main surfaces PL1 and PL2, respectively, and that detect the amount of movement of the movable unit 12. The detection unit 31 (sub-detection unit 31P) calculates the distance between the first and second detection electrodes 32A and 32B based on the capacitance generated between the first and second detection electrodes 32A and 32B. Thereby, the detection unit 32 detects the height of the gap GP. In addition, each of the sub detection units 32P is insulated from each other, and each of the sub detection units 32P performs the detection operation independently of each other.

First, by having the detection unit 32, the actual movement amount of the movable unit 12 can be measured. Further, since the detection unit 32 has the plurality of sub detection units 32P, it is possible to measure the distribution (variation) of the movement amount of the movable unit 12. In addition, by adjusting the voltage applied to the sub-driving unit 31P based on the detection result, the movable unit 12 can be moved precisely and accurately with a high degree of freedom. That is, by driving the drive unit 31 based on the detection result of the detection unit 32, it is possible to perform accurate drive adjustment with a high degree of freedom.

Further, in the present embodiment, each of the sub-detection units 32P is arranged corresponding to each sub-driving unit 31P. Therefore, the detection unit of the sub detection unit 32P corresponds to the drive unit of the sub drive unit 31P. Thereby, for example, the detection result from the sub detection unit 32P can be supplied to the corresponding sub drive unit 31P, and the driving force (applied voltage) of the sub drive unit 31P can be automatically adjusted.

In this embodiment, the driving unit 31 has a plurality of sub-driving units 31P. Moreover, the detection part 32 which detects the amount of movement of the movable part 12 is provided, and the detection part 32 has a plurality of sub detection parts 32P. Therefore, it is possible to provide the drive device 30 capable of moving the movable portion 12 accurately and accurately with a high degree of freedom.

In this embodiment, the case where the driving device 30 has the detection unit 32 and the detection unit 32 has the plurality of sub detection units 32P has been described. However, the drive device 30 does not need to have the detection unit 32. Further, the detection unit 32 is not limited to having the sub detection unit 32P.

FIG. 7A is a schematic top view of the optical filter 40 according to the fourth embodiment. FIG. 7B is a cross-sectional view taken along the line XX in FIG. The optical filter 40 has a configuration in which a reflective film pair 41 including reflective films 41A and 41B is formed on the driving device 10. In this embodiment, the optical filter 40 has first and second reflection films 41A and 41B formed on the movable portion 12 and the second main surface PL2 so as to face each other.

In this embodiment, the first and second substrates 11A and 11B have translucency. The first and second substrates 11A and 11B are made of, for example, quartz, borosilicate glass, silicon or the like. Note that in this specification, light-transmitting property refers to a property of transmitting at least part of electromagnetic waves including light (visible light).

Further, the reflective film pair 41 has a resonator characteristic of selectively transmitting electromagnetic waves. The reflective film pair 41 constitutes, for example, a Fabry-Perot etalon. The first and second reflective films 41A and 41B are thin films made of, for example, Ag and an alloy containing Ag and are transmissive reflective films (reflective films). In this embodiment, the reflective film pair 41 is formed inside the drive unit 14 and has a rotationally symmetric shape coaxial with the rotationally symmetric axis C of the movable unit 12 when seen through in a direction perpendicular to the reflective film pair 41. .. In addition, in this embodiment, the first and second reflection films 41A and 41B have a columnar shape.

Next, the filtering operation of the optical filter 40 will be described with reference to FIG. FIG. 8 is a sectional view similar to FIG. 7B, but hatching is omitted. FIG. 8 is a diagram schematically showing the input light IL from being incident on the optical filter 40 to being extracted as the selected light SL to the outside. First, for example, the input light IL enters the optical filter 40 via the first substrate 11A. The input light IL passes through the first substrate 11A and then through the first reflective film 41A.

The input light IL repeats multiple reflection between the first and second reflection films 13A and 13B. At this time, of the input light IL, light having a wavelength corresponding to the interval DT (optical gap) between the first and second reflection films 41A and 41B remains, and light having other wavelengths is attenuated. The light of the remaining wavelength passes through the second reflective film 41B as the selection light SL. The selection light SL passes through the second reflective film 41B and then exits from the second substrate 11B. In this way, the optical filter 40 selectively outputs (transmits) the incident light (electromagnetic wave).

Here, the wavelength of the electromagnetic wave transmitted through the reflective film pair 41 is determined by the distance DT between the first and second reflective films 41A and 41B. In the present embodiment, the first reflective film 41A is formed on the movable portion 12. Therefore, when the movable portion 12 is moved by the first and second drive electrodes 14A and 14B, the first reflective film 41A is displaced in the direction perpendicular to the second main surface PL2. That is, the optical gap DT of the reflective film pair 41 changes according to the movement of the movable portion 12. As a result, the wavelength selection characteristic of the optical filter 40 changes. In other words, the optical filter 40 is a variable wavelength optical filter.

In this embodiment, the movable portion 12 is accurately and precisely moved by the first and second drive electrodes 14A and 14B offset from each other. Therefore, the amount of displacement of the first reflective film 41A, that is, the optical gap DT can be adjusted accurately. Therefore, it is possible to provide the optical filter 40 capable of accurately adjusting the distance DT between the reflective films 41A and 41B.

In the present embodiment, the case where the drive device 10 has the configuration in which the reflective film pair 41 is formed has been described as the optical filter 40. However, the reflective film 41 is not limited to being provided in the drive device 10. For example, the drive device 20 or 30 may be provided with the reflective film pair 41 to configure an optical filter. For example, when the reflective film pair 41 is formed in the driving device 30, it is possible to adjust the distance DT between the reflective film pair 41 with a high degree of freedom while actually measuring it, and the optical filter becomes a high performance.

Further, as in the present embodiment, the reflective film pair 41, the supporting portion 13, and the driving portion 14 have a rotationally symmetric shape that is coaxial with the rotational symmetry axis C of the movable portion 12, so that stable adjustment of the optical gap DT can be performed. It can be carried out.

In the above, the drive electrode that generates the electrostatic force F having the component Fa in the moving direction D of the movable portion 12 and the component Fb in the direction perpendicular to the moving direction D is provided. Therefore, it is possible to provide a drive device or the like that can move the movable portion 12 with high accuracy. Further, it is possible to provide the optical filter 40 capable of accurately adjusting the interval of the reflective film and the filtering characteristics with high accuracy.

10, 10A, 10B, 20, 20A, 30 Driving Device 11A First Substrate 11B Second Substrate 12 Movable Part 13 Supports 14A, 16A, 17A, 21A, 22A, 31A First Driving Electrodes 14B, 16B, 17B , 21B, 22B, 31B Second drive electrode 32A First detection electrode 32B Second detection electrode 40 Optical filter 41A First reflection film 41B Second reflection film

Claims (1)

First and second substrates respectively having first and second main surfaces facing each other with a gap,
A movable portion whose bottom surface constitutes the first main surface and moves in a direction perpendicular to the first main surface;
A support portion that movably supports the movable portion with respect to the first substrate;
A first component in a moving direction of the movable part and a second component in a direction perpendicular to the moving direction, which are formed on the movable part and the second main surface, respectively, by applying a voltage to the movable part. A first and a second drive electrode for applying an electrostatic force having:

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