WO2019202761A1 - Spectrometer, imaging device, scanning device, and position measuring device - Google Patents

Abstract

The present invention provides a spectrometer, an imaging device, a scanning device, and a position measuring device capable of controlling the wavelength of light at high speed with high accuracy. A spectrometer (1) has a piezoelectric member (10) that has mutually parallel and opposite first principal surface (11) and second principal surface (12) with the distance between the first principal surface and the second principal surface periodically changed by the piezoelectric effect when an alternating voltage is applied thereto. The piezoelectric member allows the light entering therein to reflect multiple times between the first principal surface and the second principal surface and outputs light having a wavelength that varies in accordance with the fluctuation in the distance between the first principal surface and the second principal surface.

Description

Spectrometer, imaging device, scanning device, and position measuring device

The present invention relates to a spectroscope, an imaging device, a scanning device, and a position measuring device.

Conventionally, an etalon is known as a filter for extracting light of a desired wavelength from broadband light. An etalon is a device that extracts light of a narrow band wavelength by multiple reflection of light between two reflecting mirrors installed in parallel and facing each other.

For example, Patent Document 1 below discloses an air gap etalon that extracts light of a desired wavelength based on a gap between a wavelength conversion element that converts the wavelength of incident basic light and an optical member. .

Patent Document 2 below discloses a photoelastic modulation (PEM) element that periodically modulates the polarization state of incident light, and a plurality of polarizers and reflections provided above and below the PEM element. A tunable filter comprising a mirror is disclosed. In the wavelength tunable filter, incident light passes through the PEM element while being multiple-reflected between the upper and lower reflection mirrors, and light having a desired wavelength is emitted.

JP 2014-142422 A JP 2009-265195 A

If a wavelength to be extracted can be variably controlled using such an etalon, for example, a wavelength-swept light source can be configured. However, in the configuration disclosed in Patent Document 1, since the wavelength of light is determined according to the distance between the wavelength conversion element and the optical member, at least one of these members is mechanically controlled to control the wavelength. Needs to be moved. Therefore, the wavelength cannot be controlled at high speed depending on the configuration.

On the other hand, in the configuration disclosed in Patent Document 2, since the polarization state for each wavelength is controlled by the distortion of the PEM element, it is necessary to provide a plurality of polarizers when performing spectroscopy. Therefore, the number of parts increases, and precise adjustment of these members becomes difficult.

The present invention has been made in view of such circumstances, and an object thereof is to provide a spectroscope, an imaging device, a scanning device, and a position measuring device capable of controlling the wavelength of light at high speed and with high accuracy. To do.

A spectrometer according to one aspect of the present invention has a first main surface and a second main surface that face each other in parallel, and the distance between the first main surface and the second main surface is piezoelectric when an alternating voltage is applied. The piezoelectric member includes a piezoelectric member that periodically varies depending on the effect. The piezoelectric member multi-reflects light incident on the piezoelectric member between the first main surface and the second main surface, and the first main surface and the second main surface. The light having a wavelength that varies in accordance with the variation in the distance between the two is emitted.

According to the present invention, it is possible to provide a spectroscope, an imaging device, a scanning device, and a position measuring device that can control the wavelength of light at high speed and with high accuracy.

It is the figure which showed the spectrometer 1 which concerns on one Embodiment of this invention. FIG. 2 is a sectional view taken along line II-II in FIG. It is a figure for demonstrating the principle from which an etalon extracts a desired wavelength component. It is a figure which shows the synthetic | combination of light in case a traveling wave and a reflected wave are the same phases. It is a figure which shows the synthetic | combination of light in case a traveling wave and a reflected wave are antiphase. It is a graph which shows the light transmittance of an etalon, and the relationship of a wavelength. It is an image figure which shows the mode of a standing wave in case the thickness of the crystal piece 10 is 3 times the half wavelength. 6 is a graph showing a simulation result of light transmittance in the spectrometer 1. 6 is a graph showing a simulation result of light transmittance in the spectrometer 1. It is the figure which showed the modification of the spectrometer 1 which concerns on one Embodiment of this invention. It is the figure which showed the modification of the spectrometer 1 which concerns on one Embodiment of this invention. It is the figure which showed the modification of the spectrometer 1 which concerns on one Embodiment of this invention. It is the figure which showed the modification of the spectrometer 1 which concerns on one Embodiment of this invention. It is the figure which showed sectional drawing of the crystal piece in which a pair of electrode film was formed. It is the figure which showed sectional drawing of the crystal piece in which two pairs of electrode films were formed. It is the figure which showed the modification of the spectrometer 1 which concerns on one Embodiment of this invention. It is a figure which shows the laser apparatus with which the spectrometer which concerns on one Embodiment of this invention was applied. It is a figure which shows the inspection apparatus with which the spectrometer which concerns on one Embodiment of this invention was applied. It is a figure which shows the inspection apparatus with which the spectrometer which concerns on one Embodiment of this invention was applied. It is a figure which shows the imaging device to which the spectrometer which concerns on one Embodiment of this invention was applied. It is a figure which shows the scanning apparatus with which the spectrometer which concerns on one Embodiment of this invention was applied. It is a figure which shows the position measuring apparatus with which the spectrometer which concerns on one Embodiment of this invention was applied. It is a figure which shows the position measuring apparatus with which the spectrometer which concerns on one Embodiment of this invention was applied. It is a figure which shows the position measuring apparatus with which the spectrometer which concerns on one Embodiment of this invention was applied. 4 is a timing chart of the wavelength of light transmitted through the spectroscopes 1 and 2 and a detection signal in the detector 530. 4 is a timing chart of the wavelength of light transmitted through the spectroscopes 1 and 2 and a detection signal in the detector 530. 4 is a timing chart of the wavelength of light transmitted through the spectroscopes 1 and 2 and a detection signal in the detector 530.

Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar components are denoted by the same or similar reference numerals. The drawings are exemplary, the dimensions and shapes of each part are schematic, and the technical scope of the present invention should not be construed as being limited to the embodiments.

A spectroscope according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing a spectrometer 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

Spectroscope 1 is a device for extracting and outputting light of a desired wavelength from broadband light. As shown in FIG. 1, the spectroscope 1 includes a crystal piece 10 (Quartz Crystal Element), a pair of reflection films 20 and 21 formed on the crystal piece 10, and an AC power source that applies an AC voltage to the crystal piece 10. 30.

The crystal piece 10 is a specific example of a piezoelectric member constituting the spectrometer 1. In the present embodiment, the crystal piece 10 has, as a main surface, a plane parallel to a plane specified by the Y axis and the Z axis (optical axis) among the X axis, the Y axis, and the Z axis that are crystal axes of the artificial quartz. It is constituted by a quartz substrate of artificial quartz cut out (so-called X cut). The X axis, the Y axis, and the Z axis are orthogonal to each other, and the normal line of the main surface of the crystal piece is along the X axis. Quartz pieces using an X-cut quartz substrate are often used with the stretching vibration mode as the main vibration. Hereinafter, each configuration of the spectrometer 1 will be described with reference to the axial direction of the crystal axis.

The crystal piece 10 has a flat plate shape having two main surfaces facing each other in parallel. Specifically, the crystal piece 10 has a main surface 11 (first main surface) on the X-axis positive direction side and a main surface 12 (second main surface) on the X-axis negative direction side. The main surface 11 and the main surface 12 have a substantially rectangular shape having a long side parallel to the Z axis and a short side parallel to the Y axis in plan view. Further, the crystal piece 10 has a thickness parallel to the X axis. In the following description, the thickness parallel to the X axis is also simply referred to as “thickness”. Further, in this specification, an example in which the long side, the short side, and the side in the thickness direction of the crystal piece 10 are parallel to the corresponding crystal axes will be described as an example, but the present invention is limited to this. However, the present invention is not limited to a mode in which each side of the crystal piece 10 extends along the axis, and is strictly parallel to the axis. For example, the long side, the short side, and the side in the thickness direction may be rotated about ± 5 degrees from each crystal axis.

One reflective film 20 (first reflective film) is formed on the main surface 11 of the crystal piece 10, and the other reflective film 21 (second reflective film) is formed on the main surface 12. The pair of reflective films 20 and 21 are arranged to face each other so that substantially the whole overlaps with the crystal piece 10 interposed therebetween. Here, the pair of reflection films 20 and 21 are respectively formed on the main surfaces 11 and 12 of the crystal piece 10, and the main surface 11 and the main surface 12 of the crystal piece 10 are parallel to each other. Similarly, 20 and the reflective film 21 are arranged in parallel.

In the present embodiment, the pair of reflective films 20 and 21 also function as excitation electrodes for vibrating the quartz piece 10 by the piezoelectric effect. That is, the reflective films 20 and 21 are films formed of a conductive member, and include, for example, an electrode film. When an AC voltage is applied from the AC power source 30 to the reflective film 20 and the reflective film 21, the crystal piece 10 periodically vibrates at a high frequency (for example, MHz band) in a predetermined vibration mode such as a stretching vibration mode due to the piezoelectric effect. To do. Due to this vibration, the thickness d of the crystal piece 10 (that is, the distance between the main surface 11 and the main surface 12) periodically varies. Accordingly, the distance between the reflection films 20 and 21 formed on the main surfaces 11 and 12 also varies periodically. In addition, since the reflective films 20 and 21 also serve as the excitation electrode, the manufacturing process can be reduced as compared with the configuration in which the reflective film and the excitation electrode are provided separately.

As shown in FIG. 2, in the spectrometer 1, incident light Li is incident from an incident portion 13 that is a region of the main surface 11 of the crystal piece 10. Here, for the sake of simplicity, it is assumed that the incident light Li vibrates in the paper. Incident light Li passes through the inside of the crystal piece 10 while being reflected a plurality of times (for example, about several tens of times) between the reflection film 20 and the reflection film 21, and is a region of the main surface 12 of the crystal piece 10. Outgoing light Lo is emitted from the emitting portion 14. In FIG. 2, the incident light Li is incident so that the optical axis is inclined with respect to the main surface 12 (that is, not orthogonal to the main surface 12), and the outgoing light Lo has the optical axis as the main surface. 11 is emitted so as to have an inclination with respect to 11 (that is, without being orthogonal to the main surface 11). Next, the principle of extracting a desired wavelength component from incident light including a broadband wavelength component in a general etalon will be described before describing the effect of the thickness variation of the crystal piece 10 in the spectrometer 1.

FIG. 3 is a diagram for explaining the principle by which the etalon extracts a desired wavelength component. FIG. 4A is a diagram illustrating the light combination when the traveling wave and the reflected wave are in phase, and FIG. 4B is a diagram illustrating the light combination when the traveling wave and the reflected wave are in opposite phases.

As shown in FIG. 3, the incident light includes light of various wavelengths. While this incident light undergoes multiple reflections on parallel and opposed reflecting surfaces, the traveling wave and the reflected wave are repeatedly superimposed. Then, as shown in FIG. 4A, when the traveling wave and the reflected wave have the same phase, the intensity of light increases due to superposition, and a standing wave is generated. On the other hand, when the traveling wave and the reflected wave are out of phase, for example, in the opposite phase as shown in FIG. 4B, the light is canceled by the superposition. Therefore, light having a wavelength at which the traveling wave and the reflected wave have the same phase is selectively extracted and emitted as outgoing light. Here, the traveling wave and the reflected wave have the same phase when the integral multiple of the half wavelength of the light is equal to the distance G between the reflecting surfaces. The light intensity remains. As a result, the etalon is a band-pass filter that extracts light having a wavelength λ such that an integral multiple of a half wavelength is equal to the distance G (that is, satisfying nλ / 2 = G (n: natural number, λ: wavelength)). Function.

FIG. 5 is a graph showing the relationship between the light transmittance of the etalon and the wavelength. In the graph, the horizontal axis indicates the wavelength and the vertical axis indicates the transmittance. As described above, the etalon transmits light whose distance between the reflecting surfaces is an integral multiple of a half wavelength. Accordingly, the etalon has a characteristic that the transmittance is periodically increased with respect to the wavelength. As shown in FIG. 5, the transmittance peak-to-peak interval is referred to as FSR (Free-Spectral Range). When the incident light is swept in wavelength by the etalon, it is preferable to design the etalon so that the band of the incident light is included in the band of the FSR. Thereby, the light of a unique wavelength can be extracted.

Also in the spectroscope 1 according to the present embodiment, a desired wavelength component can be extracted by the same principle as the above-mentioned etalon. Further, according to the spectroscope 1, the wavelength to be extracted can be variably controlled by changing the thickness of the crystal piece 10. Next, the variable control of the wavelength will be described.

FIG. 6 is an image diagram showing a standing wave when the thickness of the crystal piece 10 is three times the half wavelength. From FIG. 6, when the thickness of the quartz piece 10 changes from d1 to d2, the optical path length of the light changes, so that the wavelength at which the standing wave is generated changes from λ1 to λ2. From this, it can be seen that the wavelength of the light extracted by the spectroscope 1 changes due to the change in the thickness of the crystal piece.

7A and 7B are graphs showing simulation results of light transmittance in the spectrometer 1. In the graph, the horizontal axis indicates the wavelength (nm) and the vertical axis indicates the transmittance (ratio). FIG. 7B shows a simulation result when the thickness of the crystal piece 10 is increased from 100 μm to 100.1 μm compared to FIG. 7A.

7A and 7B, it can be seen that the wavelength at which the transmittance reaches a peak is increased by increasing the thickness of the crystal piece 10. From this, it can be said that the wavelength λ of the extracted outgoing light Lo can be periodically changed by periodically changing the thickness d of the crystal piece 10.

As described above, according to the spectrometer 1, the distance between the reflective film 20 and the reflective film 21, that is, the inside of the crystal piece 10 is transmitted by periodically changing the thickness of the crystal piece 10 by the piezoelectric effect. The optical path length of light varies periodically. Thereby, the wavelength of the emitted light Lo can be varied at the same frequency (for example, about several MHz) as the vibration of the crystal piece 10. Accordingly, for example, as in the configuration disclosed in Patent Document 1, it is not necessary to mechanically move the components of the apparatus, so that the wavelength can be controlled at high speed.

For example, in the configurations disclosed in Patent Documents 1 and 2 described above, it is necessary to maintain the parallelism between the components of the apparatus or to precisely adjust the plurality of polarizers and the reflecting mirror, and all members It is difficult to ensure accuracy and maintain it. In this respect, according to the spectroscope 1, if the parallelism of the main surfaces 11 and 12 (that is, the light reflection surfaces) of the crystal piece 10 is secured, the optical path length can be changed while maintaining the parallelism of the interface. Can do. Therefore, according to the spectroscope 1, adjustment by components or the like is not required, and light can be dispersed with high accuracy and robustness against disturbance.

Furthermore, in the configuration disclosed in Patent Document 2, the transmitted light is refracted a plurality of times at the interface having different refractive indexes, so that stray light is generated every time it is refracted, and the amount of light can be lost. In this respect, in the spectroscope 1, since the number of interfaces is two as described above, the loss of light amount can be suppressed as compared with the configuration disclosed in Patent Document 2.

Further, the spectroscope 1 can be reduced in size because it requires a smaller number of parts than the configurations disclosed in Patent Documents 1 and 2.

Further, the crystal used as the piezoelectric member in the present embodiment has the following three characteristics. First, since quartz has a lower refractive index than other piezoelectric members, it is possible to suppress fluctuations in characteristics due to unintended changes in the shape of the quartz piece. Therefore, for example, even if the crystal piece expands due to a temperature change, the degradation of the spectral performance is suppressed, and the resistance to changes in the external environment is improved. Moreover, in order to ensure FSR corresponding to broadband incident light, it is necessary to reduce the thickness of the member with a higher refractive index. In this regard, according to quartz, even when it corresponds to broadband incident light, it can be made thicker than other members. Therefore, according to the present embodiment, processability and strength can be ensured as compared with a configuration in which another piezoelectric member is used.

Second, quartz has a faster response to fluctuations in AC voltage than other piezoelectric members. Therefore, according to the present embodiment, it is possible to control the wavelength at a higher speed than in a configuration in which other piezoelectric members are used.

Third, quartz has a wider wavelength band that can be transmitted than other piezoelectric members. In addition, even when the wavelength of light is relatively short and the energy is strong, the quartz crystal hardly deteriorates its optical characteristics and progresses slowly. Therefore, according to the present embodiment, for example, it is possible to transmit light rays having wavelengths from ultraviolet rays to infrared rays.

In addition, in this embodiment, the crystal piece 10 is X-cut and vibrates in the stretching vibration mode. Therefore, vibration of about MHz is easily excited, and a wider spectral bandwidth can be obtained compared to other vibration modes.

In the above-described embodiment, the case where the crystal piece is X-cut and vibrates in the stretching vibration mode has been described, but the crystal cut angle and vibration mode are not limited thereto. For example, the crystal piece is obtained by rotating the Y-axis and the Z-axis among the X-axis, the Y-axis, and the Z-axis that are the crystal axes of the artificial quartz by about 51 degrees around the X-axis from the Y-axis to the Z-axis. The X 'axis, the Y' axis, and the Z 'axis are obtained by rotating the X' axis and the Z 'axis around the Y' axis by about 45 degrees in the direction from the Z 'axis to the X' axis, respectively. When the axes are the X ″ axis, the Y ″ axis, and the Z ″ axis, respectively, a cut (so-called GT) cut out with a plane parallel to the plane specified by the X ″ axis and the Z ″ axis. You may be comprised by the quartz substrate cut | disconnected. In such a GT cut, the normal of the main surface has an inclination of about 39 degrees with respect to the Z axis. In this case, the variation in the thickness of the crystal piece (and hence the bandwidth of the wavelength of the emitted light) is reduced as compared with the X-cut, and temperature stability can be obtained. Therefore, resistance to environmental fluctuations can be improved compared to X-cut.

When a GT-cut crystal piece is used, the optical path lengths of the forward path and the return path are not the same due to the influence of birefringence because the symmetry between the light traveling direction and the axial direction is lost between the two main surfaces. Can also be considered. However, if the optical path lengths in the reciprocation are the same, the polarization and phase in the reciprocation are the same, so that the same function as in the above-described embodiment is achieved. As a method for calculating the optical path length, a known method can be used (for example, refer to Japanese Patent Application Laid-Open No. 2008-076120), and thus description thereof is omitted.

Further, the crystal piece may be constituted by a crystal substrate cut out by another cut such as a so-called AT cut. The material of the piezoelectric member is not limited to quartz, and may be made of a material different from quartz.

Furthermore, in the above-described embodiment, an example in which the reflection films 20 and 21 have the function of the excitation electrode and an AC voltage is applied to the reflection films 20 and 21 is shown, but the member to which the AC voltage is applied is It is not limited to this. For example, the spectroscope 1 may include an excitation electrode for applying an AC voltage separately from the reflection films 20 and 21 that multiple-reflect light.

In addition, the spectroscope 1 may be provided with an antireflection film for reducing the reflectance at one or both of the incident portion 13 where the light is incident and the emitting portion 14 where the light is emitted. A reflection film to be enhanced may be formed. These can be appropriately designed according to, for example, the amount of incident light Li incident from a light source and the amount of light necessary as outgoing light Lo.

Next, a spectroscope according to a modification of the present embodiment will be described with reference to FIGS. FIGS. 8 to 11 and 13 are diagrams showing modifications of the spectrometer 1 according to an embodiment of the present invention. In the following description, the same elements as those of the spectrometer 1 are denoted by the same reference numerals and the description thereof is omitted. Further, description of matters common to the spectrometer 1 is omitted, and only different points will be described. In particular, the same operation effect by the same configuration will not be sequentially described for each embodiment.

In the spectroscope 1 </ b> A shown in FIG. 8, the side surfaces 15 and 16 disposed between the main surface 11 and the main surface 12 of the crystal piece 10 a are inclined with respect to the main surfaces 11 and 12.

Specifically, the side surface 15 on one side (positive side) in the Z-axis direction of the crystal piece 10a is an inclined surface (first inclined surface) inclined with respect to the main surface 11. Further, the side surface 16 on the other side (negative direction side) in the Z-axis direction of the crystal piece 10 a is an inclined surface (second inclined surface) that is inclined with respect to the main surface 12. The side surface 15 and the side surface 16 are disposed at positions facing each other between the main surface 11 and the main surface 12.

In the spectroscope 1A, incident light Li is incident from the side surface 15 and outgoing light Lo is emitted from the side surface 16. Thereby, for example, even if light is incident on the side surface 15 perpendicularly, the light is incident on the main surface 12 of the crystal piece 10a with an inclination (that is, not orthogonal). Accordingly, light incident on the crystal piece 10a from a light source (not shown) is prevented from being reflected by the reflective film 21a and returning to the light source again, so that damage and noise to the light source can be suppressed.

In addition, when light enters and exits from a surface different from the light reflection surface as in the spectroscope 1A, the reflection films 20a and 21a are formed on the entire main surfaces 11 and 12 of the crystal piece 10a. Also good. Further, the side surfaces 15 and 16 do not necessarily have an inclined surface as a whole, and for example, a part of the side surface may include an inclined surface, and light may enter and exit from the inclined surface. .

The spectroscope 1B shown in FIG. 9 includes electrode films 22a and 23a instead of the reflective films 20 and 21 as compared to the spectroscope 1 shown in FIG. Similarly, the spectrometer 1C shown in FIG. 10 includes electrode films 22b and 23b instead of the reflection films 20 and 21.

Specifically, in the spectroscope 1B, the electrode film 22a is formed on the main surface 11 of the crystal piece 10b so as to surround the incident portion 17 of the incident light Li located in the central region. Also on the main surface 12, an electrode film 23 a is formed so as to surround the periphery of the emission part 18 of the emitted light Lo. The electrode films 22a and 23a face each other through the crystal piece 10b, and an AC voltage is applied from the AC power supply 30. The incident portion 17 and the emission portion 18 may be provided with a highly reflective coating that transmits part of the light and reflects part of the light.

Even in such a configuration, the thickness of the peripheral region of the crystal piece 10b varies due to the piezoelectric effect, so that the thickness of the central region also varies with the variation, and the same effect as the above-described spectrometer 1 is obtained. be able to.

Thus, in the spectroscope, the electrode film having the function of vibrating the crystal piece and the reflection film having the function of reflecting incident light are not necessarily shared, and may be provided separately. Further, the spectroscopes 1B and 1C may have an arrangement in which the main surface is inclined with respect to the traveling direction of the incident light, similarly to the spectroscope 1A.

It should be noted that the electrode films 22a and 23a do not necessarily need to surround the entire central region, and for example, there may be discontinuities in some of the electrode films 22b and 23b shown in FIG. Thereby, for example, when the electrode films 22b and 23b are formed on the crystal piece 10c by vapor deposition, the film forming process is facilitated.

In the spectroscope 1D shown in FIG. 11, the crystal piece 10d has a circular flat plate shape. Thus, the shape of the crystal piece is not particularly limited, and may be a rectangular flat plate shape, a circular flat plate shape, or a polygonal flat plate shape.

In addition, the crystal piece 10d has an annular inner electrode film 24x formed around the incident portion located near the center of the circle on one main surface, and further has an annular shape so as to surround the outer side of the inner electrode film 24x. The outer electrode film 24y (outer electrode film) is formed concentrically. The inner electrode film 25x and the outer electrode film 25y are also formed on the other main surface so as to face the inner electrode film 24x and the outer electrode film 24y, respectively. An AC voltage is applied from the AC power supply 31 to the inner electrode film 24x and the inner electrode film 25x, and an AC voltage is applied from the AC power supply 32 to the outer electrode film 24y and the outer electrode film 25y.

Thus, the electrode film formed on the crystal piece is not limited to a pair, and may be two or more pairs. At this time, AC voltages having different phases may be applied to the two pairs of electrode films. This effect will be described.

FIG. 12A is a diagram showing a cross-sectional view of a crystal piece on which a pair of electrode films are formed, and FIG. 12B is a diagram showing a cross-sectional view of the crystal piece on which two pairs of electrode films are formed. 12A and 12B show cross sections in the same direction as in FIG. 2, and the electrode film is omitted for convenience of explanation.

As shown in FIG. 12A, an alternating voltage is applied to a pair of electrode films (for example, an electrode film corresponding to the inner electrode film 24x and the inner electrode film 25x shown in FIG. 11) partially formed in the plane. In this case, due to the piezoelectric effect, for example, the peripheral region of the crystal piece may be thick and the central region may be thin. Thereby, the parallelism of the reflecting surface in the region where the light is multiple-reflected may deteriorate, and the spectral accuracy may be reduced. On the other hand, as shown in FIG. 12B, when AC voltages having opposite phases, for example, are applied to two pairs of electrode films, the crystal piece in the region facing the inner electrode film tends to become thicker, while the outer electrode film The crystal pieces in the area where the two face each other are going to be thin. Thereby, nonuniformity of the thickness of the crystal piece is suppressed, and as a result, the parallelism of the reflecting surface in the region where the light is multiply reflected is improved. As described above, the spectroscope 1D improves the accuracy of spectroscopy compared to a configuration including a pair of electrode films.

In the spectroscope 1D, the case where the crystal piece 10d is a circular flat plate has been described as an example. However, even if the crystal pieces have different shapes, two pairs of electrode films may be formed in the same manner. Further, the electrode films formed on the quartz piece are not limited to two pairs, and may be three or more pairs.

In the spectroscope 1E shown in FIG. 13, a plurality of electrode films 26 and 27 and a plurality of highly reflective films 40 and 41 are formed on both main surfaces of the crystal piece 10e.

The plurality of electrode films 26 and 27 have a function of an excitation electrode, and an AC voltage is applied from the AC power supply 30. The plurality of high reflection films 40 and 41 are reflection films having a higher reflectance than the main surface of the crystal piece and the electrode films 26 and 27. The members of the highly reflective films 40 and 41 are not particularly limited, but may be, for example, a conductive film or a dielectric film. In the spectroscope 1E, the plurality of electrode films 26 and the plurality of highly reflective films 40 are alternately arranged along the light traveling direction (Z-axis direction) on one main surface of the crystal piece 10e. Similarly, a plurality of electrode films 27 and a plurality of highly reflective films 41 are alternately arranged along the light traveling direction (Z-axis direction) on the other main surface of the crystal piece 10e.

As described above, in the spectroscope 1E, the electrode films 26 and 27 and the high reflection films 40 and 41 are used in combination, so that the amount of light loss due to multiple reflection is reduced as compared with the configuration without the high reflection films 40 and 41. It is suppressed, and attenuation of the light quantity of the emitted light Lo can be suppressed.

The above-described spectroscopes 1A to 1E are examples of modifications of the spectroscope 1, and the configuration of the present invention is not limited to this. For example, in the above-described embodiment, the configuration in which the electrode film is provided on a part of the main surface of the crystal piece is shown, but the electrode film may be provided on the entire main surface of the crystal piece. When the electrode film is provided on the entire main surface, the electrode film may be formed of a member having a property of transmitting and reflecting light of a predetermined wavelength, such as ITO (Indium Tin Oxide). preferable.

Further, in the above-described embodiment, a configuration is shown in which a pair of opposing reflective films are formed on the main surface of the crystal piece, but the reflecting member that multi-reflects light is not necessarily on the main surface of the crystal piece. The film may not be formed directly, and may be disposed on one main surface side and the other main surface side, respectively. Specifically, for example, a pair of reflecting members may be provided so as to be separated from the main surface of the crystal piece and to be parallel and opposed to each other with the crystal piece interposed therebetween. In this case, the incident light incident on the spectroscope is subjected to multiple reflections between these reflecting members while passing through the crystal piece a plurality of times.

Next, with reference to FIGS. 14 to 17, an application example of the spectrometer 1 according to an embodiment of the present invention will be described.

FIG. 14 is a diagram showing a laser apparatus to which a spectroscope according to an embodiment of the present invention is applied. A laser apparatus 100 shown in the figure includes a spectrometer 1, a laser diode 110, a lens 120, an optical fiber 130, and an amplifier 140. In addition, in FIG. 14, although the structure of the spectrometer 1B is illustrated, the spectrometer applied to the laser apparatus 100 is not specifically limited. The same applies to the following application examples.

In the laser device 100, the light emitted from the laser diode 110 that is a light source is dispersed in the spectroscope 1, and the dispersed light is output via the lens 120 and the optical fiber 130. The amplifier 140 is a device that amplifies the amount of light, and includes, for example, an SOA (Semiconductor Optical Amplifier). Note that the laser apparatus 100 may include a plurality of amplifiers 140 to compensate for the loss of light quantity, and the light quantity may be amplified a plurality of times. In addition, the position where the amplifier 140 is disposed may be the rear stage of the spectroscope 1 or the front stage of the spectroscope 1.

By applying the spectroscope 1 to the laser device 100, a laser device capable of variably controlling the wavelength at high speed can be realized as described above.

FIG. 15 is a diagram showing an inspection apparatus to which a spectroscope according to an embodiment of the present invention is applied. The inspection apparatus 200 shown in the figure includes a spectrometer 1, a plurality of light sources 210, lenses 220 and 230, and a detector 240 (imaging device).

In the inspection apparatus 200, light emitted from the plurality of light sources 210 to the object W on the conveyor is incident on the spectrometer 1 through the lens 220. The light split by the spectroscope 1 is input to the detector 240 via the lens 230.

Here, if the inspection apparatus does not include the spectroscope 1, it is necessary to simultaneously detect light of a plurality of wavelengths (for example, red, yellow, green, blue, etc.) with the detector 240. Therefore, in the inspection of the color of the object W, it is necessary to use a multi-pixel imaging device as the detector 240, and a mechanism for assigning a color to each pixel is required. For example, this is performed by a lens and a color filter arranged directly above the grating or each pixel. However, if the number of pixels is increased in order to improve spectral performance, an increase in size is inevitable. On the other hand, if it is intended to reduce the size, the pixel pitch of the image sensor of the detector 240 must be reduced to have low sensitivity, and a long exposure time is required. That is, in this case, high-speed spectroscopy cannot be performed. In particular, when a grating is used, since the pixel pitch becomes small, crosstalk noise between signals due to adjacent wavelengths tends to occur, and this tendency becomes remarkable.

In this regard, since the inspection apparatus 200 includes the spectroscope 1, light whose wavelength varies at a high frequency is supplied to the detector 240. Thereby, the light incident on the detector 240 can be appropriately changed according to time such as red, yellow, green, blue, red,... As described above, since the spectroscope 1 performs the spectroscopic analysis, the number of necessary pixels may be small as compared with the configuration in which the light having a plurality of wavelengths is simultaneously supplied to the detector 240. As a result, the area per pixel can be increased and the sensitivity can be increased, and the exposure time can be shortened. Furthermore, if the number of pixels is small, reading can be performed at high speed. Thus, since the wavelength change of the spectrometer 1 is performed at high speed and the detector 240 can also detect light at high speed, the color of the object W that is being moved by the conveyor as compared with the configuration that does not include the spectrometer 1. Can be inspected at high speed. Moreover, since the interference between wavelengths is suppressed by the spectroscope 1, it is possible to avoid the occurrence of crosstalk between signals. The detector 240 may be, for example, a single pixel detector, or binning processing may be performed in which a plurality of pixels are handled as one pixel.

FIG. 16 is a diagram showing an inspection apparatus to which a spectroscope according to an embodiment of the present invention is applied. Compared to the inspection apparatus 200 shown in FIG. 15, the inspection apparatus 300 shown in FIG. 15 is configured to scan light with respect to a stationary object W instead of moving the object W. Specifically, the inspection apparatus 300 further includes a lens 310, a beam splitter 320, and a scanner 330, as compared with the inspection apparatus 200.

In the inspection apparatus 300, the light emitted from the light source 210 enters the scanner 330 through the lens 310 and the beam splitter 320. The scanner 330 is a device that includes one or more mirrors and scans light when the mirror operates, and is configured by, for example, a two-dimensional galvanometer mirror. The light emitted from the scanner 330 and applied to the object W through the lens 220 is incident on the spectroscope 1 again through the lens 220, the scanner 330 and the beam splitter 320. The light split by the spectroscope 1 is input to the detector 240 via the lens 230.

As described above, even when the object W is stationary, the color or the like of the object W can be detected by scanning the light using the scanner 330. Note that a one-dimensional galvanometer mirror may be used as the scanner 330 and a plurality of detectors 240 may be provided.

Further, the arrangement of the spectroscope 1 may not be in front of the detector 240, and may be, for example, between the light source 210 and the lens 310. In this case, due to the loss of the light amount in the spectroscope 1, the light amount of the light irradiated to the object decreases. Therefore, it functions suitably when the object is difficult to irradiate with strong light, such as biological observation. Furthermore, the spectroscope 1 may be inserted in both the subsequent stage of the light source 210 and the previous stage of the detector 240, and the plurality of spectroscopes 1 may be operated in synchronization. According to this, it is possible to obtain a sharper wavelength selectivity than in the configuration in which the spectrometer 1 is inserted in either one, and to perform spectroscopy with higher resolution. In the above-described embodiment, for the sake of simplicity, the light source 210 has been described as emitting visible light. However, the wavelength of light emitted from the light source 210 is not limited to visible light. For example, by using a light source that irradiates light of near-infrared wavelength with deep reachability, it can also be used for an inspection apparatus that inspects the inside of a painted surface.

Next, a configuration example of the imaging apparatus when the spectrometer 1 is applied as a wavelength swept light source will be described with reference to FIG.

FIG. 17 is a diagram illustrating an imaging apparatus to which a spectroscope according to an embodiment of the present invention is applied. An imaging apparatus 400 shown in the figure is an example of an optical tomographic imaging apparatus that captures an optical tomographic image of a living body. Specifically, the imaging apparatus 400 includes a spectrometer 1, a light source 410, a measurement optical system 420, a reference optical system 430, a detector 440, a timing control system 450, and a signal processing system 460.

The spectroscope 1 sweeps the wavelength of broadband light incident from the light source 410 and emits it. The measurement optical system 420 measures the object W using a part of the emitted light from the spectrometer 1. The reference optical system 430 uses another part of the light emitted from the spectrometer 1 as reference light. The detector 440 detects the measurement interference light based on the reflected light from the object W and the reference light from the reference optical system 430, and outputs the measurement interference signal to the signal processing system 460. The detector 440 is constituted by, for example, a balanced photodetector.

The timing control system 450 transmits a trigger signal corresponding to the wavelength of the emitted light from the spectrometer 1 to the signal processing system 460, and controls the arithmetic processing of the signal processing system 460. Specifically, the timing control system 450 includes an FBG 451, a circulator 452, and a detector 453. The FBG (Fiber Bragg Grating) 451 has a property of reflecting only a predetermined wavelength (so-called Bragg wavelength) component of incident light and transmitting other wavelength components. Accordingly, when the light emitted from the spectrometer 1 is supplied to the FBG 451, the reflected light is emitted from the FBG 451 when the Bragg wavelength component of the FBG 451 is incident. The reflected light is supplied to the detector 453 via the circulator 452. The detector 453 controls the arithmetic processing in the signal processing system 460 by detecting the reflected light and transmitting a trigger signal to the signal processing system 460.

The signal processing system 460 performs arithmetic processing based on the measurement interference signal transmitted from the detector 440 and the trigger signal transmitted from the timing control system 450 and outputs a tomographic image of the object W. As described above, according to the imaging apparatus 400, a captured image of the object W can be obtained while controlling the wavelength of light applied to the object W.

In general, optical tomographic imaging devices are often used under in-vivo conditions, so it is possible to suppress artifacts (virtual images) caused by the movement of the living body that is the object or to repeatedly capture similar parts. Therefore, it is required to sweep the wavelength of the light source at high speed. Therefore, the spectroscope 1 functions suitably in such an optical tomographic imaging apparatus.

Note that the configuration of the timing control is not limited to the configuration shown in FIG. For example, instead of including the timing control system 450, the imaging apparatus 400 may insert an FBG between the measurement optical system 420 and the detector 440. In this case, the light detected by the detector 440 is interrupted only when the wavelength of the light incident from the measurement optical system 420 matches the Bragg wavelength. The wavelength of the light emitted from the spectroscope 1 can be detected at this interrupted timing.

In addition, the imaging device 400 may include a control device that synchronously controls the light emission timings of the detector 440 and the light source 410 instead of including the timing control system 450. Thereby, the object W can be irradiated with light of a desired wavelength. Alternatively, the imaging apparatus 400 may include a detector that detects the wavelength of the emitted light from the spectrometer 1 instead of including the timing control system 450. For example, the detector may be a detector that outputs light of a predetermined wavelength and detects the wavelength of the light emitted from the spectrometer 1 by detecting a beat signal with the light emitted from the spectrometer 1.

Furthermore, the imaging device using the spectroscope 1 is not limited to this. For example, an optical tomographic imaging apparatus (see Japanese Patent Application Laid-Open No. 2017-2012257) that obtains a tomographic image of the cornea, retina, etc. of an eyeball, or a disease such as degeneration of biological tissue or cancer that detects fluorescence contained in a living body The present invention may be applied to a fluorescence diagnostic apparatus (see Japanese Patent Application Laid-Open No. 2005-305182) for diagnosing a state.

FIG. 18 is a diagram showing a scanning device to which a spectroscope according to an embodiment of the present invention is applied. The scanning device 500 shown in the figure includes a spectrometer 1, a light source 510, and a prism 520.

In the scanning device 500, broadband light emitted from the light source 510 is dispersed by the spectroscope 1, and further refracted and emitted by the prism 520 with a different refractive index depending on the wavelength. As described above, according to the scanning device 500, the light temporally dispersed by the spectroscope 1 is spatially dispersed by the prism 520, so that light that scans a certain area at high speed and periodically can be emitted. . Such a scanning device 500 can be applied as a scanner that spatially scans light from a light source in, for example, LIDAR (Light Detection and Ranging) described below. Note that the spectroscopic element that spatially separates light in the scanning device 500 is not limited to a prism, and may be, for example, a grating. The same applies to the position measuring apparatus 600 described below.

19A to 19C are diagrams showing a position measuring device to which the spectroscope according to one embodiment of the present invention is applied. 19A to 19C further includes a spectroscope 2 configured similarly to the spectroscope 1 and a detector 530, in addition to the scanning device 500 described above.

The spectroscope 2 transmits the reflected light emitted from the scanning device 500 at different angles according to the wavelength and reflected from the object X. The detector 530 receives and detects the reflected light that has passed through the spectroscope 2. That is, in the position measurement apparatus 600, the spectroscope 1 (first spectroscope) has a function of periodically changing the wavelength of the emitted light, and the spectroscope 2 (second spectroscope) is a specific wavelength of the reflected light. It has a function as a filter that transmits light.

Specifically, FIG. 19A shows a state in which light of a certain wavelength is reflected by the object X at the point A. FIG. 19B shows a state in which light having the same wavelength as that of the point A is reflected on the object X at the point B closer to the position measuring device 600 than the point A. FIG. 19C shows a state in which light having a wavelength different from that in the case of point A and point B is reflected on the object X in the point C located in a different direction from the point A and point B. In any of these cases, based on the difference between the emission time at which the light source 510 emits light and the detection time at which the detector 530 detects the reflected light reflected by the object X, the object X is detected by the so-called Time of Flight method. Can be calculated. This principle will be described below.

20A to 20C are timing charts of the wavelength of light transmitted through the spectroscopes 1 and 2 and the detection signal in the detector 530 in the situation shown in FIGS. 19A to 19C, respectively. For the sake of simplicity, description will be made assuming that light of three types of wavelengths (wavelength 1 to wavelength 3) is emitted from the prism 520.

In the position measurement apparatus 600, the light source side spectroscope 1 and the detection side spectroscope 2 are controlled synchronously. Specifically, as shown in FIGS. 20A to 20C, the vibration frequency of the piezoelectric element of the detection-side spectrometer 2 (that is, the wavelength fluctuation frequency of the transmitted light of the spectrometer 2) is the light-source-side spectrometer. It is controlled so as to be higher than the vibration frequency of the piezoelectric element 1 (that is, the frequency fluctuation wavelength of the transmitted light of the spectrometer 1). Thereby, the light of a specific wavelength can be selectively detected.

Specifically, for example, when the object X is at the point A (see FIG. 19A), the light of wavelength 3 emitted at time t1 is reflected by the object X. The reflected light reaches the spectroscope 2 and is supplied to the detector 530 when the spectroscope 2 is in a state of transmitting light of wavelength 3. The detection signal in detector 530 indicates that light has been detected at time t2. Thereby, the distance d from the position measuring apparatus 600 to the object X can be calculated by d = c (t2−t1) / 2 (c is the speed of light). Since light is emitted from the prism 520 at different angles depending on the wavelength, the light of the wavelength 1 and the wavelength 2 does not hit the object X, and the reflected light does not return.

Similarly, for example, when the target object X is at the point B (see FIG. 19B), the light of wavelength 3 emitted at time t1 is reflected by the target object X, the reflected light reaches the spectroscope 2, and The detector 2 is supplied to the detector 530 when the device 2 is in a state of transmitting light of wavelength 3. Thereby, the detection signal in detector 530 indicates that light was detected at time t2. Also in this case, the light of the wavelength 1 and the wavelength 2 does not hit the object X, and the reflected light does not return.

On the other hand, for example, when the object X is at the point C (see FIG. 19C), the light of wavelength 2 emitted at time t1 is reflected by the object X, and the reflected light reaches the spectroscope 2, and the spectroscope 2 is supplied to the detector 530 when light of wavelength 2 is transmitted. Thereby, the detection signal in detector 530 indicates that light was detected at time t2. In this case, light of wavelength 1 and wavelength 3 does not strike the object X, and reflected light does not return. As described above, the position measurement apparatus 600 can measure the azimuth of the position where the object is located according to the wavelength of the reflected light detected by the detector 530. When performing spatial scanning using a prism as described above, the wavelength can be converted into an angle using the refractive index dispersion of the glass material constituting the prism and the law of refraction (Snell's law). .

As described above, according to the position measuring apparatus 600, the distance d from the position measuring apparatus 600 to the object can be calculated based on the difference between the time t1 and the time t2. In addition, according to the position measuring apparatus 600, it is possible to calculate in which direction the object X is located based on the wavelength of light detected by the detector 530. That is, according to the position measuring apparatus 600, it is not necessary to move the parts of the apparatus mechanically compared to LIDAR, for example, by rotating a light source or a mirror to expand the emission area of the emitted light, so that measurement is performed at high speed and with high accuracy. be able to. Although an example of two-dimensional scanning has been described above for the sake of simplicity, three-dimensional scanning can be realized by using a plurality of prisms or using a hologram element.

The exemplary embodiments of the present invention have been described above. The spectroscope according to the present embodiment has a first main surface and a second main surface that face each other in parallel, and the distance between the first main surface and the second main surface due to application of an alternating voltage is caused by the piezoelectric effect. The piezoelectric member is provided with a periodically changing piezoelectric member, and the piezoelectric member multi-reflects light incident on the piezoelectric member between the first main surface and the second main surface, and between the first main surface and the second main surface. The light having a wavelength that varies according to the variation in the distance is emitted.

According to this, since the optical path length of the light is changed by the piezoelectric effect, it is not necessary to mechanically move parts of the apparatus, and the wavelength can be variably controlled at high speed. In addition, since the optical path length can be changed while maintaining the parallelism between the first main surface and the second main surface of the piezoelectric member, adjustment by components or the like is not required, and light is robust and highly accurate against disturbance. Spectroscopy is possible.

In the above configuration, the spectroscope 1 further includes a first reflection film provided on the first main surface side and a second reflection film provided on the second main surface side, and the piezoelectric member includes the first reflection film. The light may be multiple-reflected between the film and the second reflective film.

According to this, since the reflectance is increased as compared with the configuration without the reflective film, it is possible to suppress the loss of light amount.

In the above configuration, each of the first reflective film and the second reflective film may include an electrode film to which an alternating voltage is applied.

According to this, since the reflective film also serves as the excitation electrode, the manufacturing process can be reduced.

In the above configuration, each of the first reflective film and the second reflective film may include a high reflective film having a higher reflectance than the electrode film.

According to this, the loss of the light amount due to the multiple reflection is suppressed, and the attenuation of the light amount of the emitted light can be suppressed.

In the above configuration, the first reflective film and the second reflective film are each an inner electrode film and an outer electrode film provided so as to surround the outer side of the inner electrode film in a plan view of the first main surface or the second main surface. AC voltages having opposite phases may be applied to the inner electrode film and the outer electrode film.

According to this, nonuniformity of the thickness of the crystal piece is suppressed and the parallelism of the reflecting surface in the region where the light is multiply reflected is improved, so that the accuracy of spectroscopy is improved.

In the above configuration, the piezoelectric member further includes a first inclined surface that is inclined with respect to the first main surface, and a second inclined surface that is inclined with respect to the second main surface, and the first inclined surface and the second inclined surface. The inclined surface may be disposed at a position facing each other between the first main surface and the second main surface, and the piezoelectric member may emit light incident from the first inclined surface from the second inclined surface.

According to this, it is avoided that the light incident on the piezoelectric member from the light source is reflected and returned to the light source again, and damage and noise to the light source can be suppressed.

In the above configuration, the piezoelectric member may be configured by an X-cut artificial quartz crystal.

According to this, since the piezoelectric member vibrates in the expansion / contraction vibration mode, it is possible to widen the spectral bandwidth compared to other vibration modes.

In the above configuration, the piezoelectric member may be formed of a GT-cut artificial quartz crystal.

According to this, it is possible to obtain temperature stability as compared with the X-cut artificial quartz. Therefore, resistance to environmental fluctuations can be improved.

The imaging apparatus according to the present embodiment is reflected by the above-described spectroscope, a light source that makes light incident on the piezoelectric member of the spectroscope, an optical system that irradiates the object with light emitted from the spectroscope, and the object. And an imaging device that receives the reflected light.

According to this, it is possible to provide a light source that is wavelength-swept at high speed. Therefore, for example, in an apparatus that captures an optical tomographic image of a living body, artifacts due to the movement of the living body can be suppressed, and the imaging accuracy when imaging is repeated can be improved.

The scanning device according to the present embodiment includes the above-described spectroscope, a light source that makes light incident on the piezoelectric member of the spectroscope, and a spectroscopic element that spatially splits the light emitted from the spectroscope.

According to this, since the light spectrally dispersed by the spectroscope is spatially dispersed by the spectroscopic element, it is possible to emit light that scans a certain area at high speed and periodically.

The position measuring apparatus according to the present embodiment is the above-described spectroscope, and includes a first spectroscope that transmits incident light, a light source that enters light into a piezoelectric member of the first spectroscope, and an output from the first spectroscope. A spectroscopic element that spatially separates the emitted light, the above-described spectroscope, a second spectroscope that transmits reflected light emitted from the spectroscopic element and reflected by the object, and transmitted through the second spectroscope And a detector for receiving the transmitted light.

According to this, the distance from the position measuring device to the object can be calculated based on the difference between the emission time and the detection time. Further, according to this, it is possible to calculate in which direction the object is located based on the wavelength of the detected light. Therefore, it is not necessary to mechanically move the parts of the apparatus, for example, compared to LIDAR that rotates a light source or a mirror, and therefore, measurement can be performed at high speed and with high accuracy.

In the above configuration, the vibration frequency of the piezoelectric member of the second spectrometer may be higher than the vibration frequency of the piezoelectric member of the first spectrometer.

According to this, it is possible to selectively detect light of a specific wavelength.

Each embodiment described above is for facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed or improved without departing from the gist thereof, and equivalents thereof are also included in the present invention. In other words, those obtained by appropriately modifying the design of each embodiment by those skilled in the art are also included in the scope of the present invention as long as they include the features of the present invention. For example, each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate. In addition, each element included in each embodiment can be combined as much as technically possible, and combinations thereof are included in the scope of the present invention as long as they include the features of the present invention.

DESCRIPTION OF SYMBOLS 1,1A-1E ... Spectroscope, 10, 10a-10e ... Quartz piece, 11, 12 ... Main surface, 13 ... Incident part, 14 ... Outgoing part, 15, 16 ... Side, 20, 20a, 21, 21a ... Reflection Film, 22a, 22b, 23a, 23b, 26, 27 ... electrode film, 24x, 25x ... inner electrode film, 24y, 25y ... outer electrode film, 30-32 ... AC power supply, 40, 41 ... highly reflective film, 100 ... Laser device, 110 ... laser diode, 120 ... lens, 130 ... optical fiber, 140 ... amplifier, 200 ... inspection device, 210 ... light source, 220,230 ... lens, 240 ... detector, 300 ... inspection device, 310 ... lens, 320 ... Beam splitter, 330 ... Scanner, 400 ... Imaging device, 410 ... Light source, 420 ... Measurement optical system, 430 ... Reference optical system, 440 ... Detector, 450 ... Timing control system, 451 ... FBG, 452 ... circulator, 453 ... detector, 460 ... signal processing system, 500 ... scanning device 510 ... light source, 520 ... prism, 530 ... detector, 600 ... position measuring device

Claims (12)

1. A piezoelectric member having a first main surface and a second main surface facing each other in parallel, wherein a distance between the first main surface and the second main surface is periodically changed by a piezoelectric effect by application of an alternating voltage. With
   The piezoelectric member multi-reflects light incident on the piezoelectric member between the first main surface and the second main surface, and a variation in the distance between the first main surface and the second main surface. A spectrometer that emits light having a wavelength that varies depending on the wavelength.
2. The spectroscope further includes a first reflective film provided on the first main surface side, and a second reflective film provided on the second main surface side,
   The piezoelectric member multi-reflects light between the first reflective film and the second reflective film,
   The spectroscope according to claim 1.
3. Each of the first reflective film and the second reflective film includes an electrode film to which the AC voltage is applied.
   The spectroscope according to claim 2.
4. Each of the first reflective film and the second reflective film includes a high reflective film having a higher reflectance than the electrode film.
   The spectroscope according to claim 3.
5. The first reflective film and the second reflective film are respectively an inner electrode film and an outer electrode provided so as to surround the outer side of the inner electrode film in a plan view of the first main surface or the second main surface. A membrane, and
   AC voltages having opposite phases are applied to the inner electrode film and the outer electrode film,
   The spectroscope according to claim 2.
6. The piezoelectric member further includes a first inclined surface that is inclined with respect to the first main surface, and a second inclined surface that is inclined with respect to the second main surface,
   The first inclined surface and the second inclined surface are disposed at positions facing each other between the first main surface and the second main surface,
   The piezoelectric member emits light incident from the first inclined surface from the second inclined surface,
   The spectroscope according to any one of claims 1 to 5.
7. The piezoelectric member is composed of an X-cut artificial quartz crystal,
   The spectroscope according to any one of claims 1 to 6.
8. The piezoelectric member is composed of a GT-cut artificial quartz crystal,
   The spectroscope according to any one of claims 1 to 6.
9. A spectrometer according to any one of claims 1 to 8,
   A light source that makes light incident on the piezoelectric member of the spectroscope;
   An optical system for irradiating an object with light emitted from the spectroscope;
   An imaging device comprising: an imaging device that receives reflected light reflected by the object.
10. A spectrometer according to any one of claims 1 to 8,
    A light source that makes light incident on the piezoelectric member of the spectroscope;
    And a spectroscopic element that spatially separates the light emitted from the spectroscope.
11. The spectroscope according to any one of claims 1 to 8, wherein the first spectroscope transmits incident light;
    A light source that makes light incident on the piezoelectric member of the first spectrometer;
    A spectroscopic element for spatially dispersing light emitted from the first spectroscope;
    The spectroscope according to any one of claims 1 to 8, wherein the second spectroscope transmits the reflected light emitted from the spectroscopic element and reflected by an object;
    And a detector that receives the transmitted light that has passed through the second spectroscope.
12. The vibration frequency of the piezoelectric member of the second spectrometer is higher than the vibration frequency of the piezoelectric member of the first spectrometer.
    The position measuring device according to claim 11.

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