Spectroscope and analysis device

Abstract

To provide a compact and inexpensive spectroscope.SOLUTION: The spectroscope is provided with a light incidence means for making light from the outside incident. In addition, the spectroscope includes a diffraction grating that wavelength-disperses the light incident by the light incidence means. The spectroscope also includes a reflection means having a reflection surface for reflecting the light wavelength-dispersed by the diffraction grating, wherein the inclination of the reflection surface is variable.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spectrometer and an analytical device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a so-called spectroscope is known that separates measurement light into wavelengths to obtain a spectrum for each wavelength.

[0003] A typical spectrometer is configured with a concave diffraction grating that separates incident measurement light into light of multiple wavelengths, and an array sensor that can detect each of the light of multiple wavelengths (see, for example, Patent Document 1 below). For example, a Si photodiode, an InGaAs photodiode, or the like is used for the array sensor. Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the array sensors used in spectrometers are large and expensive, it has been impossible to provide a small, low-cost spectrometer.

[0005] SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the conventional technology, an object of the present invention is to provide a small, low-cost spectrometer. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the spectrometer of the present invention is characterized by comprising: light incident means for incident light from outside; a diffraction grating for wavelength-dispersing the light incident by the light incident means; and reflecting means having a reflecting surface for reflecting the light wavelength-dispersed by the diffraction grating, the inclination of which can be freely changed. [Effects of the Invention]

[0007] According to the present invention, a small and low-cost spectrometer can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a conceptual diagram showing the configuration of a spectrometer according to a first embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating a configuration of a light reflecting unit according to a first embodiment of the present invention. [Figure 3] 3 is a cross-sectional view of the light reflecting unit shown in FIG. 2 taken along line AA'. FIG. [Figure 4] 3 is a cross-sectional view of the light reflecting unit shown in FIG. 2 along the line BB'. FIG. [Figure 5] 1 is a schematic diagram showing a first configuration example of a concave diffraction grating according to a first embodiment of the present invention. [Figure 6] FIG. 3 is a schematic diagram showing a second configuration example of the concave diffraction grating according to the first embodiment of the present invention. [Figure 7] FIG. 4 is a schematic diagram showing a third configuration example of the concave diffraction grating according to the first embodiment of the present invention. [Figure 8] FIG. 2 is a conceptual diagram showing a first modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 9] FIG. 4 is a conceptual diagram showing a second modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a conceptual diagram showing a third modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 11] FIG. 10 is a conceptual diagram showing a fourth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 12] FIG. 10 is a conceptual diagram showing a fifth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 13] FIG. 10 is a conceptual diagram showing a sixth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 14] FIG. 10 is a conceptual diagram showing a seventh modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 15] FIG. 10 is a conceptual diagram showing an eighth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. [Figure 16] FIG. 4 is a conceptual diagram showing the configuration of a spectrometer according to a second embodiment of the present invention. [Figure 17] 10 is a schematic diagram showing the configuration (first example) of a specific wavelength detector according to a second embodiment of the present invention. FIG. [Figure 18] FIG. 10 is a schematic diagram of a configuration (second example) of a specific wavelength detector according to a second embodiment of the present invention. [Figure 19] FIG. 10 is a diagram showing an example of an output signal of a specific wavelength detector according to the second embodiment of the present invention. [Figure 20] FIG. 10 is a diagram showing an example of an output signal of a specific wavelength detector according to the second embodiment of the present invention. [Figure 21] FIG. 10 is a diagram showing an example of an output signal of a specific wavelength detector according to the second embodiment of the present invention. [Figure 22] 10 is a diagram showing an example of a time waveform of the deflection angle of a movable light reflecting portion according to the second embodiment of the present invention. FIG. [Figure 23] FIG. 10 is a conceptual diagram showing a first modified example of the configuration of the spectrometer according to the second embodiment of the present invention. [Figure 24] FIG. 10 is a conceptual diagram showing a second modified example of the configuration of the spectrometer according to the second embodiment of the present invention. [Figure 25] FIG. 10 is a conceptual diagram showing a third modified example of the configuration of the spectrometer according to the second embodiment of the present invention. [Figure 26] FIG. 10 is a conceptual diagram showing a fourth modified example of the configuration of the spectrometer according to the second embodiment of the present invention. [Figure 27] FIG. 10 is a conceptual diagram showing another configuration of the spectrometer according to the second embodiment of the present invention. [Figure 28] 1 is a conceptual diagram showing the configuration of a spectroscopic measurement device using a spectroscope according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] A first embodiment of the present invention will be described below with reference to the drawings.

[0010] (Configuration of spectrometer 10A) Fig. 1 is a conceptual diagram showing the configuration of a spectrometer 10A according to a first embodiment of the present invention. The spectrometer 10A shown in Fig. 1 is an example of the "spectrometer" of the present invention. This spectrometer 10A is configured to include a light input section 1, a concave diffraction grating 2, a movable light reflecting section 3, a light output section 4, a substrate 5, and another substrate 6.

[0011] The light incident section 1 is an example of the "light incident means" of the present invention. The light incident section 1 is formed with a light passing section 1a. The light incident section 1 causes light irradiated from the outside to pass through the light passing section 1a, thereby causing the light to enter the spectrometer 10A. The light passing section 1a has, for example, a pinhole shape, a slit shape, or the like. The light incident section 1 is provided for the purpose of, for example, determining the incident position of light or improving wavelength resolution.

[0012] The concave diffraction grating 2 is an example of the "diffraction grating" of the present invention. The concave diffraction grating 2 is formed on a substrate 5. The concave diffraction grating 2 wavelength-disperses the light that enters the spectrometer 10A from the light incident unit 1. The light (diffracted light) that has been wavelength-dispersed by the concave diffraction grating 2 is reflected toward the movable light reflector 3. The material of the substrate 5 may be, for example, a semiconductor, glass, metal, resin, or the like, but is not limited to these. The concave diffraction grating 2 may be formed directly on the substrate 5, or may be formed on a thin film layer (for example, a resin layer) formed on the substrate 5.

[0013] The movable light reflector 3 is an example of the "reflection means" of the present invention. The movable light reflector 3 is disposed on the same plane as the substrate 6 within the opening 6a of the substrate 6. The movable light reflector 3, together with the substrate 6, constitutes a light reflecting unit 11. The movable light reflector 3 reflects the diffracted light dispersed by the concave diffraction grating 2 toward the light emitting portion 4. The movable light reflector 3 has a rotation axis 3a. The movable light reflector 3 is configured to change the inclination of the reflective surface that reflects the diffracted light by rotating around the rotation axis 3a. Materials for the substrate 6 include, but are not limited to, semiconductors, glass, metals, and resins. However, using a semiconductor as the material for the substrate 6 makes it possible to form a very thin and compact movable light reflector 3 using semiconductor processes, MEMS processes, and the like. Furthermore, using a semiconductor as the material for the substrate 6 allows for monolithic formation of driving elements, such as piezoelectric, electrostatic, and electromagnetic drivers, on the substrate 6. This allows the movable light reflecting portion 3 to be driven without using an external driving device such as a motor, thereby enabling the spectrometer 10A to be further miniaturized.

[0014] The light emitting unit 4 is an example of the "light emitting means" of the present invention. The light emitting unit 4 has a light passing unit 4a formed therein. The light emitting unit 4 emits the diffracted light reflected by the movable light reflecting unit 3 to the outside by passing the diffracted light through the light passing unit 4a at its focal position. The light passing unit 4a has, for example, a pinhole shape or a slit shape. The light emitting unit 4 is provided for the purpose of, for example, determining the emission position of the diffracted light or improving wavelength resolution.

[0015] The light incident portion 1 and the light emitting portion 4 may also be formed on a substrate. In this case, the substrate may be made of, for example, a semiconductor, glass, metal, resin, etc., but is not limited to these. However, by using a semiconductor as the substrate material, the light incident portion 1 and the light emitting portion 4 can be formed with high precision and low cost using a semiconductor process, an MEMS process, etc.

[0016] In spectrometer 10A, the above components are arranged at predetermined positions as shown in FIG. 1, and are fixed to a housing, a jig, or the like so that they can maintain predetermined attitudes.

[0017] (Configuration of light reflecting unit 11) Here, a specific configuration of the light reflecting unit 11 will be described with reference to FIGS. 2 to 4. FIG. 2 is a schematic diagram of the configuration of the light reflecting unit 11 according to the first embodiment of the present invention. As shown in FIG. 2, the light reflecting unit 11 is configured to have a movable light reflecting portion 3, a substrate 6, a driving circuit 7 (an example of the "driving means" of the present invention), and a beam portion 8. The movable light reflecting portion 3 is disposed in an opening 6a of the substrate 6 on the same plane as the substrate 6. The opening 6a is formed using a MEMS (Micro Electro Mechanical Systems) process such as anisotropic deep etching. The movable light reflecting portion 3 is supported by the beam portion 8 at both one end of the rotation shaft 3a and the other end of the rotation shaft 3a.

[0018] 2, the movable light reflecting portion 3 is configured to include a thin film portion 3b and a reflecting member 3c superimposed on the reflecting surface side of the thin film portion 3b. The reflecting member 3c is provided to improve the reflectance of the movable light reflecting portion 3. For example, a thin film Si layer of an SOI (Silicon On Insulator) substrate can be used for the thin film portion 9. For example, a metal material such as Al, Ag, Au, or Pt can be used for the reflecting member 10.

[0019] FIG. 3 is an A-A′ cross-sectional view of the light reflecting unit 11 shown in FIG. 2. In the example of FIG. 3, the beam 8 is configured by superimposing, from the top in the figure (positive direction of the Z axis), a thin film portion 8a, an electrode 8b, a piezoelectric film 8d, and an electrode 8c. The beam 8 configured in this manner functions as an actuator when a voltage is applied to the piezoelectric film 8d from the drive circuit 7 (see FIG. 2) via the electrodes 8b and 8c, and can rotate the movable light reflecting unit 3. For example, in order to emit diffracted light of a desired wavelength to the outside, it is necessary to tilt the movable light reflecting unit 3 at a predetermined angle corresponding to the wavelength. For example, the drive circuit 7 can tilt the movable light reflecting unit 3 at a predetermined angle by applying a predetermined voltage to the piezoelectric film 8d or by feeding back the angle detected by a tilt sensor provided in the movable light reflecting unit 3 to the voltage applied to the piezoelectric film 8d. Note that the drive method of the movable light reflecting unit 3 is not limited to piezoelectric drive, and other drive methods (e.g., electrostatic drive, electromagnetic drive, etc.) may also be used.

[0020] Fig. 4 is a cross-sectional view taken along the line B-B' of the light reflecting unit 11 shown in Fig. 2. As shown in Fig. 4, the movable light reflecting part 3 is driven by the beam part 8 as described in Fig. 3, and is configured to rotate clockwise and counterclockwise around the rotation axis 3a, thereby changing the tilt of the reflecting surface that reflects diffracted light.

[0021] (Configuration example of concave diffraction grating 2) Next, a specific configuration of the concave diffraction grating 2 will be described with reference to FIGS.

[0022] Fig. 5 is a schematic diagram showing a first configuration example of a concave diffraction grating 2 according to the first embodiment of the present invention. In the example shown in Fig. 5, the concave diffraction grating 2 is configured to include a resin layer 14 and a reflecting member 15. Specifically, a concave curved surface is formed on the upper surface of a substrate 5, and a thin-film resin layer 14 is formed on this concave curved surface. A diffraction grating is then formed on the resin layer 14. Furthermore, a reflecting member 15 made of a metal material such as Al, Ag, Au, or Pt is formed on the surface of the diffraction grating to improve reflectance.

[0023] For example, when a Si substrate is used as the substrate 5, a pattern for forming a concave curved surface can be formed on the substrate 5 by using a grayscale mask, nanoimprint technology, or the like to form a pattern for forming a concave curved surface on a resist applied to the substrate 5, and then performing dry etching or the like to form a concave curved surface on the substrate 5. Alternatively, a diffraction grating can be formed in the resin layer 14 by forming a resin layer 14 on the concave curved surface of the substrate 5, and transferring a separately prepared concave diffraction grating mold to the resin layer 14 and curing it.

[0024] FIG. 6 is a schematic diagram showing a second configuration example of the concave diffraction grating 2 according to the first embodiment of the present invention. In the example shown in FIG. 6, the concave diffraction grating 2 is configured to include a reflective member 15. Specifically, a concave curved surface is formed on the upper surface of the substrate 5, and a diffraction grating is formed on this concave curved surface. Furthermore, a reflective member 15 made of a metal material such as Al, Ag, Au, or Pt is formed on the surface of the diffraction grating to improve reflectance. For example, a diffraction grating can be formed on the concave curved surface of the substrate 5 by applying a resist to the concave curved surface of the substrate 5, forming a grating pattern in the resist using interference exposure or the like, and then performing dry etching or the like.

[0025] FIG. 7 is a schematic diagram showing a third configuration example of the concave diffraction grating 2 according to the first embodiment of the present invention. In the example shown in FIG. 7, the concave diffraction grating 2 is configured to include a resin layer 14 and a reflecting member 15. Specifically, the resin layer 14 is formed on the upper surface (flat surface) of the substrate 5. A concave curved surface is formed on the upper surface of the resin layer 14, and a diffraction grating is formed on this concave curved surface. Furthermore, a reflecting member 15 made of a metal material such as Al, Ag, Au, or Pt is formed on the surface of the diffraction grating to improve reflectance. For example, the resin layer 14 can be formed on the upper surface (flat surface) of the substrate 5, and a separately prepared concave diffraction grating mold can be transferred to the resin layer 14 and cured to form a diffraction grating in the resin layer 14. The configuration of FIG. 7 omits the step of forming a concave curved surface on the substrate 5, thereby simplifying the process.

[0026] As the concave diffraction grating 2 of FIGS. 5 to 7, for example, the cross-sectional shape of the grooves of the diffraction grating can be rectangular, sinusoidal, sawtooth, or the like.

[0027] 5 to 7 may be configured without the reflecting member 15. The configuration of the concave diffraction grating 2 is not limited to the examples shown in FIGS. 5 to 7. That is, the concave diffraction grating 2 may have a configuration other than that shown in FIGS. 5 to 7 as long as it has a similar wavelength dispersion function. When parallel light is incident from the light incident portion 1, a similar wavelength dispersion function can also be achieved by using a plane diffraction grating instead of the concave diffraction grating 2. In this case, a complex device configuration (for example, a collimating optical system for collimating light before and after the plane diffraction grating) that would be required when adopting a configuration in which the inclination of the plane diffraction grating is changed is not necessary.

[0028] (Actions and effects of the spectrometer 10A) The spectrometer 10A of this embodiment, configured as described above, can change the wavelength of the diffracted light emitted from the light emitting unit 4 by driving the movable light reflector 3 to change the inclination of the reflecting surface of the movable light reflector 3. Specifically, the focal length of the diffracted light wavelength-dispersed by the concave diffraction grating 2 varies depending on the wavelength. Therefore, the spectrometer 10A changes the inclination of the reflecting surface of the movable light reflector 3 so that the position of the light passing section 4a of the light emitting unit 4 corresponds to the focal length of the diffracted light of the desired wavelength. As a result, as shown in FIG. 1, the diffracted light of the desired wavelength is emitted from the light passing section 4a of the light emitting unit 4. Note that the dashed line in FIG. 1 schematically shows the optical path of light of a specific wavelength. That is, FIG. 1 shows how the inclination of the reflecting surface of the movable light reflector 3 is set so that diffracted light of a specific wavelength is emitted.

[0029] As described above, the spectrometer 10A of this embodiment allows diffracted light of a desired wavelength to be emitted from the light passing portion 4a of the light emitting portion 4 by adjusting the tilt of the reflecting surface of the movable light reflecting portion 3. Therefore, the spectrometer 10A of this embodiment can obtain the spectrum of diffracted light of a desired wavelength using a single external optical sensor. In other words, the spectrometer 10A of this embodiment can obtain the spectrum of diffracted light of various wavelengths without using a large and expensive array sensor. Therefore, the spectrometer 10A of this embodiment can provide a small and low-cost spectrometer.

[0030] Furthermore, according to the spectrometer 10A of this embodiment, diffracted light of a desired wavelength is emitted from the light passing portion 4a of the light emitting portion 4 by changing the tilt of the reflecting surface of the movable light reflecting portion 3 without changing the tilt of the concave diffraction grating 2. Therefore, the spectrometer 10A of this embodiment does not require a complex device configuration (for example, a configuration to accommodate changes in the angle of incidence of light on the concave diffraction grating 2) that would be required if a configuration for changing the tilt of the concave diffraction grating 2 were adopted. Therefore, according to the spectrometer 10A of this embodiment, diffracted light of a desired wavelength can be emitted from the light passing portion 4a of the light emitting portion 4 with a relatively simple configuration.

[0031] Furthermore, according to spectrometer 10A of this embodiment, incident light is reflected twice, once by concave diffraction grating 2 and once by concave diffraction grating 2. Therefore, according to spectrometer 10A of this embodiment, the configuration can be simplified compared to a configuration in which light is reflected three or more times (for example, the configuration of Patent Document 1), and a decrease in the amount of light due to reflection loss can be suppressed.

[0032] The spectrometer 10A of this embodiment can be combined with at least a photodetector that detects the diffracted light emitted from the light passing portion 4a of the light emitting portion 4 to form a spectroscopic device. In this case, a photodetector having a single optical sensor can be used as the photodetector. The spectrometer 10A of this embodiment can be combined with at least an optical fiber that guides the diffracted light emitted from the light passing portion 4a of the light emitting portion 4 to form a monochromator.

[0033] (Modification of the spectrometer configuration) Modified examples of the spectrometer configuration will be described. Note that in each of the modified examples described below, changes from the spectrometers previously described will be described. Furthermore, in each modified example, components having the same functions as components previously described will be assigned the same reference numerals as the previously described components, and descriptions thereof will be omitted. Furthermore, in each modified example, the operating principles, etc. of the spectrometer are the same as those previously described, and descriptions thereof will be omitted.

[0034] (First Modification) FIG. 8 is a conceptual diagram showing a first modified example of the configuration of the spectrometer according to the first embodiment of the present invention. 8, the light incident portion 1 and the movable light reflecting portion 3 are formed on the same substrate 6. In addition, in the spectrometer 10B, the light exit portion 4 and the concave diffraction grating 2 are formed on the same substrate 5. For example, when Si substrates are used for the substrates 5 and 6, the light incident portion 1 and the light exit portion 4 can be integrally formed on the substrates 5 and 6, respectively, using a semiconductor process, an MEMS process, or the like.

[0035] According to this spectrometer 10B, the light incident portion 1 and the light output portion 4 can be formed on the substrates 5 and 6 with high positional accuracy using a semiconductor process. That is, according to this spectrometer 10B, alignment adjustment between the light incident portion 1 and the movable light reflector 3 and between the light output portion 4 and the concave diffraction grating 2 is not necessary, making overall alignment adjustment easier. Furthermore, according to this spectrometer 10B, a configuration can be achieved in which no part of the housing or jigs are interposed between the light incident portion 1 and the movable light reflector 3, and between the light output portion 4 and the concave diffraction grating 2. Therefore, according to this spectrometer 10B, the distance between the light incident portion 1 and the movable light reflector 3 and the distance between the light output portion 4 and the concave diffraction grating 2 can be shortened, thereby enabling the realization of a more compact spectrometer.

[0036] (Second Modification) FIG. 9 is a conceptual diagram showing a second modified example of the configuration of the spectrometer according to the first embodiment of the present invention. In the spectrometer 10C shown in FIG. 9, the light entrance section 1 and the light exit section 4 are formed on the same substrate 16.

[0037] According to this spectrometer 10C, it is possible to form the light incident portion 1 and the light output portion 4 with high positional accuracy on the substrate 16 using a semiconductor process. That is, according to this spectrometer 10C, alignment adjustment between the light incident portion 1 and the light output portion 4 is not necessary, and therefore overall alignment adjustment becomes easier.

[0038] (Third Modification) FIG. 10 is a conceptual diagram showing a third modified example of the configuration of the spectrometer according to the first embodiment of the present invention. Spectrometer 10D shown in FIG. 10 differs from spectrometer 10B shown in FIG. 8 in that a pair of spacers 17 is further arranged between substrate 5 and substrate 6. Substrate 5 is an example of a "second substrate" in the present invention. Substrate 6 is an example of a "first substrate" in the present invention. Spacer 17 is an example of an "intervening member" in the present invention. Each of substrates 5 and 6 is bonded to spacer 17. Spacer 17 may be, for example, columnar or plate-shaped. The distance between substrate 5 and substrate 6 is adjusted to an appropriate distance by adjusting the thickness of spacer 17 so as to obtain the desired spectral characteristics.

[0039] In this spectrometer 10D, the distance between the substrate 5 and the substrate 6 is adjusted to an appropriate distance by the thickness of the spacer 17 so that the desired spectral characteristics can be obtained. Therefore, in the spectrometer 10D, alignment adjustment between the substrate 5 and the substrate 6 is not necessary. Note that in the spectrometer 10D, a substrate can also be used for the spacer 17. In this case, the spacer 17 can be formed with higher precision by using a semiconductor process. Furthermore, multiple spacers 17 can be formed collectively with high precision on a wafer. This makes it possible to realize a spectrometer with less variation and at a lower price.

[0040] (Fourth Modification) FIG. 11 is a conceptual diagram illustrating a fourth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. Spectrometer 10E shown in FIG. 11 differs from spectrometer 10D shown in FIG. 10 in that light exit portion 4 is formed on substrate 5 to the right of concave diffraction grating 2 (positive side of the Y axis in the figure). In spectrometer 10E, the grating pitch of concave diffraction grating 2 is wider than in spectrometer 10D shown in FIG. 10. This changes the diffraction angle of concave diffraction grating 2, and therefore the position of light exit portion 4 is changed in spectrometer 10E. In spectrometer 10E, the grating pitch of concave diffraction grating 2 is larger than in spectrometer 10D, making it easier to manufacture concave diffraction grating 2. Therefore, spectrometer 10E can reduce manufacturing variations and achieve lower costs compared to spectrometer 10D.

[0041] (Fifth Modification) Fig. 12 is a conceptual diagram showing a fifth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. Spectrometer 10F shown in Fig. 12 differs from spectrometer 10D shown in Fig. 10 in that concave diffraction grating 2 is arranged on substrate 5 so that the perpendicular to the center of concave diffraction grating 2 is not perpendicular to the substrate surface of substrate 5, and concave diffraction grating 2 is tilted toward light incident section 1 (negative side of the Y axis in the figure) with respect to substrate 5.

[0042] With the spectrometer 10F configured in this manner, it is possible to adjust the angle of incidence of the diffracted light on the movable light reflector 3 by changing the inclination of the concave diffraction grating 2, thereby controlling the required deflection angles in the positive and negative directions of the movable light reflector 3 to be equal. Therefore, with the spectrometer 10F, it is possible to reduce the deflection angle of the movable light reflector 3 while still being able to measure the same wavelength range. As a result, with the spectrometer 10F, it is possible to drive the movable light reflector 3 with a smaller driving force. Therefore, with the spectrometer 10F, it is possible to miniaturize the components (e.g., drive element, drive circuit, power supply, etc.) required to drive the movable light reflector 3, and the spectrometer This allows for further miniaturization and cost reduction of the spectrometer. Furthermore, spectrometer 10F can reduce the amount of twist in beam 8 that supports movable light reflector 3, thereby reducing stress generated in beam 8. Therefore, spectrometer 10F can improve the stability and reliability of the rotation angle of movable light reflector 3.

[0043] (Sixth Modification) Fig. 13 is a conceptual diagram showing a sixth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. Spectrometer 10G shown in Fig. 13 differs from spectrometer 10D shown in Fig. 10 in that spacer 17 on the left side (negative side of the Y axis in the figure) is replaced with substrate 19, and that light entrance section 1 and light exit section 4 are formed on substrate 19.

[0044] Substrate 19 is an example of a "third substrate" of the present invention. Substrate 19 is disposed between substrates 5 and 6, non-parallel and perpendicular to substrates 5 and 6. Substrates 5 and 6 are each bonded to substrate 19. Materials that can be used for substrate 19 include, but are not limited to, semiconductors, glass, metals, and resins. However, by using a semiconductor as the material for substrate 19, it is possible to form very thin and small light incident section 1 and light emitting section 4 using semiconductor processes, MEMS processes, and the like.

[0045] According to this spectrometer 10G, the light incident portion 1 and the light output portion 4 can be formed on the substrate 19 with high positional accuracy using a semiconductor process. That is, according to this spectrometer 10G, alignment adjustment between the light incident portion 1 and the light output portion 4 is not required, and therefore overall alignment adjustment is easy. Note that in the spectrometer 10G, the light incident portion 1 may be formed on the substrate 6, and the light output portion 4 may be formed on the substrate 19. Alternatively, in the spectrometer 10G, the light incident portion 1 may be formed on the substrate 19, and the light output portion 4 may be formed on the substrate 5.

[0046] (7th and 8th variants) FIG. 14 is a conceptual diagram showing a seventh modified example of the configuration of the spectrometer according to the first embodiment of the present invention. FIG. 15 is a conceptual diagram showing an eighth modified example of the configuration of the spectrometer according to the first embodiment of the present invention. Spectrometer 10H shown in FIG. 14 differs from spectrometer 10A shown in FIG. 1 in that a photodetector 18 is provided at the position of light output unit 4 instead of light output unit 4. Spectrometer 10I shown in FIG. 15 differs from spectrometer 10B shown in FIG. 8 in that a photodetector 18 is provided at the position of light output unit 4 instead of light output unit 4. Photodetector 18 of spectrometers 10H and 10I is an example of the "photodetection means" of the present invention.

[0047] According to the spectrometers 10H and 10I, there is no need to provide an external light detection unit 18, making it possible to realize a more compact spectrometer. The light detection unit 18 may have a light-receiving surface formed in the same shape (e.g., pinhole or slit shape) as the light passage unit 4a formed in the light emission unit 4. Alternatively, the light detection unit 18 may have a light-shielding member above the light-receiving surface, the light-shielding member having the same shape as the light emission unit 4. The light-receiving surface, the light-shielding member, and the like can be monolithically formed on a semiconductor substrate using a semiconductor process. Therefore, the light detection unit 18 can be manufactured to be thin and compact.

[0048] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Figures 16 to 26. In this second embodiment, an example will be described in which a spectrometer is further provided with a specific wavelength detector.

[0049] (Configuration of spectrometer 50A) Fig. 16 is a conceptual diagram showing the configuration of a spectrometer 50A according to a second embodiment of the present invention. The spectrometer 50A shown in Fig. 16 differs from the spectrometer 10A of the first embodiment (Fig. 1) in that it further includes a specific wavelength detector 20.

[0050] The specific wavelength detector 20 is an example of the "specific wavelength detecting means" of the present invention. The specific wavelength detector 20 is provided near the focal position of the emitted light (i.e., the position of the light emitting unit 4). The specific wavelength detector 20 is capable of detecting light of a specific wavelength λs, and is provided near the light emitting unit 4. By detecting light of a specific wavelength λs with the specific wavelength detector 20, the spectrometer 50A can detect whether the deflection angle of the movable light reflecting unit 3 is sufficient for the desired measurement wavelength range (λm to λx) or whether the deflection angle is constant.

[0051] For example, when an InGaAs photodiode is used as the photodetector, the measurement wavelength range of the spectrometer 50A can be set to 900 to 1700 nm or 900 to 2500 nm. In this case, the specific wavelength λs may be shorter than the minimum wavelength of 900 nm in the measurement wavelength range, or longer than the maximum wavelength of 1700 nm or 2500 nm in the measurement wavelength range. In particular, by setting the specific wavelength λs to a wavelength of approximately 1000 nm or less, a Si photodiode can be used, making it possible to realize this configuration at lower cost.

[0052] The dashed line in Fig. 16 roughly indicates the optical path of light with the minimum wavelength λm in the measurement wavelength range, while the dashed line in Fig. 16 roughly indicates the optical path of light with a specific wavelength λs.

[0053] (Configuration of specific wavelength detector 20) Here, a specific configuration of the specific wavelength detector 20 will be described with reference to FIGS. 17 and 18. FIG. 17 is a schematic diagram of a configuration (first example) of the specific wavelength detector 20 according to the second embodiment of the present invention. For example, as shown in FIG. 17, the specific wavelength detector 20 is configured to include a photodetector 21 and a bandpass filter 22. The photodetector 21 is an example of the "photodetection unit" of the present invention. The photodetector 21 detects light of a specific wavelength λs. For example, a Si photodiode, an InGaAs photodiode, or the like is used as the photodetector 21. The bandpass filter 22 transmits light in a specific wavelength range (including the specific wavelength λs within the range). It is preferable to use a filter with a narrow passband (for example, a Fabry-Perot filter, or the like) as the bandpass filter 22.

[0054] FIG. 18 is a schematic diagram of a configuration (second example) of a specific wavelength detector 20 according to a second embodiment of the present invention. As shown in FIG. 18, the specific wavelength detector 20 may further include a light-shielding member 23. The shape and size of the light-transmitting portion of the light-shielding member 23 may be appropriate as needed. Instead of using the band-pass filter 22, the light-shielding member 23, and the photodetector 21, the specific wavelength detector 20 may use a photodetector that functions as a band-pass filter and a light-shielding member. FIG. 27 is a conceptual diagram showing another configuration of a spectrometer 50A according to the second embodiment of the present invention. As shown in FIG. 27, the specific wavelength detector 20 may be formed integrally with the light-emitting unit 4. For example, if the light-emitting unit 4 is formed of a Si substrate and the specific wavelength detector 20 is a Si photodiode, the two can be formed monolithically. Furthermore, since the bandpass filter 22 can be formed, for example, by a Fabry-Perot filter using a semiconductor process, and the light-shielding member 23 can also be formed by a metal thin film using a semiconductor process, it is possible to integrally form the configuration of the specific wavelength detector 20 shown in Fig. 18 on the light emitting portion 4. Furthermore, depending on the shape of the Si photodiode, it is possible to obtain the same function without forming the light-shielding member 23.

[0055] 19 to 21 are diagrams showing an example of an output signal of the specific wavelength detector 20 according to the second embodiment of the present invention. 19 to 21 show an example of an output signal when light of a specific wavelength λs is detected by the specific wavelength detector 20. If the resonant frequency of the movable light reflector 3 is f, the drive period T is 1 / f.

[0056] 19 shows a state in which the angular amplitude of the movable light reflector 3 matches the measurement wavelength range (λm to λx). In this case, for example, if λs=λm, light of a specific wavelength λs is detected at the maximum position of the deflection angle of the movable light reflector 3, and therefore a detection signal of the specific wavelength λs is output once every period T.

[0057] 20 shows a state where there is a margin in the angular amplitude of the movable light reflector 3 relative to the measurement wavelength range (λm to λx). In this case, a detection signal for a specific wavelength λs is output twice at a period T.

[0058] 21 shows a state in which there is no margin for the angular amplitude of the movable light reflector 3 relative to the measurement wavelength range (λm to λx). In this case, the amplitude of the detection signal for the specific wavelength λs decreases. Furthermore, when the angular amplitude of the movable light reflector 3 decreases, the detection signal for the specific wavelength λs is no longer output.

[0059] In the case of a spectrometer, the measurement wavelength range (λm to λx) must be constantly maintained, so the state shown in FIG. 19 or the state shown in FIG. 20, where the angular amplitude of the movable optical reflector 3 has a margin, is required. In particular, in the case of FIG. 20, it is possible to detect the angular amplitude of the movable optical reflector 3 by detecting the time Td or Ts between two peaks, without depending on the amplitude of the detection signal of a specific wavelength λs. Furthermore, by controlling the drive of the movable optical reflector 3 to keep Td or Ts constant, the measurement wavelength range (λm to λx) can be kept constant. Therefore, by detecting the light emitted from the light emitting unit 4 within the range of Ts, it is possible to obtain a desired optical spectrum. Furthermore, if the resonant frequency f of the movable optical reflector 3 may fluctuate, Td changes depending on the value of f. Therefore, by measuring the period T (= 1 / f), it is possible to control Td to a constant value according to the resonant frequency f, and thereby obtain a desired spectrum.

[0060] Note that the range of T is the driving range for one round trip of the movable light reflector 3, so in reality, two spectra are obtained. Half of this data may be used as the spectral data, or an average value may be used.

[0061] FIG. 22 is a diagram showing an example of a time waveform of the deflection angle of the movable light reflector 3 according to the second embodiment of the present invention. The solid line in FIG. 22 represents a state in which the deflection angle matches the measurement wavelength range (the state in FIG. 19 ). At the maximum deflection angle, light of the minimum wavelength λm is emitted from the light emitting unit 4 (the state in FIG. 19 ). The dashed line in FIG. 22 represents a state in which the deflection angle is equal to or greater than the measurement wavelength range (the state in FIG. 20 ). In this example, the deflection angle exceeds the deflection angle corresponding to the minimum wavelength λm near the maximum positive value, so a specific wavelength λs is detected at the timing when the deflection angle corresponds to the minimum wavelength λm. Therefore, as shown in FIG. 20 , two detection signals are detected consecutively per cycle. The dashed line in FIG. 22 represents a state in which the deflection angle is insufficient (the state in FIG. 21 , or a state in which the output of a specific wavelength λs is 0).

[0062] The detection result of the specific wavelength detector 20 is output to, for example, the drive circuit 7 and used for feedback control of the rotation angle of the movable light reflector 3. In this case, for example, the drive circuit 7 may control the time interval Td or Ts of the detection signal of the specific wavelength λs to be constant, thereby controlling the rotation angle of the movable light reflector 3 to be constant.

[0063] (Modification of the spectrometer configuration) Modified examples of the spectrometer configuration will be described. Note that in each of the modified examples described below, changes from the spectrometers previously described will be described. Furthermore, in each modified example, components having the same functions as components previously described will be assigned the same reference numerals as the previously described components, and descriptions thereof will be omitted. Furthermore, in each modified example, the operating principles, etc. of the spectrometer are the same as those previously described, and descriptions thereof will be omitted.

[0064] (First Modification) Fig. 23 is a conceptual diagram showing a first modified example of the configuration of the spectrometer according to the second embodiment of the present invention. In spectrometer 50B shown in Fig. 23, light incident portion 1 and movable optical reflector 3 are formed on the same substrate 6. In spectrometer 50B, light exit portion 4, concave diffraction grating 2, and specific wavelength detector 20 are formed on the same substrate 5. For example, when Si substrates are used for substrates 5 and 6, light incident portion 1 and light exit portion 4 can be integrally formed on substrates 5 and 6, respectively, using a semiconductor process, an MEMS process, or the like.

[0065] In the spectrometer 50B, the specific wavelength detector 20 may include a photodetector 21 and a bandpass filter 22 (see FIG. 17), or may further include a light-shielding member 23 (see FIG. 18). In the former case, the photodetector 21 and the bandpass filter 22 can be formed monolithically on the substrate 5, for example, because a Fabry-Perot filter or the like can be formed using a semiconductor process. In the latter case, the light-shielding member 23 can also be formed integrally with the photodetector 21 and the bandpass filter 22, because a metal thin film or the like can be formed using a semiconductor process.

[0066] With the spectrometer 50B configured in this manner, the specific wavelength detector 20 can be integrally formed on the substrate 5, thereby enabling further miniaturization. Furthermore, with the spectrometer 50B, by forming the light emitting unit 4 and the specific wavelength detector 20 using a semiconductor process, a highly accurate positional relationship can be achieved between the light emitting unit 4 and the specific wavelength detector 20. Therefore, with the spectrometer 50B, it is possible to accurately detect the deflection angle of the movable light reflecting unit 3 and stabilize the measurement wavelength range.

[0067] (Second Modification) FIG. 24 is a conceptual diagram illustrating a second modified example of the configuration of the spectrometer according to the second embodiment of the present invention. Spectrometer 50C shown in FIG. 24 differs from spectrometer 50B shown in FIG. 23 in that a light-emitting unit 24 is formed on substrate 5 at a focusing position for light of a specific wavelength λs, and specific wavelength detector 20 is externally disposed. Light-emitting unit 24 is an example of the "second light-emitting means" of the present invention. Spectrometer 50C configured in this manner does not include specific wavelength detector 20 formed on substrate 5, simplifying the manufacturing process for substrate 5. Meanwhile, light-emitting unit 4 and light-emitting unit 24 can be simultaneously formed on substrate 5 using the same process, allowing for precise control of their relative positions. Therefore, spectrometer 50C can accurately detect the deflection angle of movable light reflector 3 and stabilize the measurement wavelength range.

[0068] (Third Modification) Fig. 25 is a conceptual diagram showing a third modified example of the configuration of the spectrometer according to the second embodiment of the present invention. Spectrometer 50D shown in Fig. 25 differs from spectrometer 50C shown in Fig. 24 in that detector 21 and bandpass filter 22, which are components of specific wavelength detector 20, are arranged separately from each other. Specifically, bandpass filter 22 is arranged on substrate 5 so as to cover light output portion 24. Meanwhile, detector 21 is arranged externally. According to spectrometer 50C configured in this manner, only detector 21 is arranged externally, and therefore it can be made smaller than a configuration in which bandpass filter 22 is also arranged externally.

[0069] (Fourth Modification) Fig. 26 is a conceptual diagram showing a fourth modified example of the configuration of the spectrometer according to the second embodiment of the present invention. Spectrometer 50E shown in Fig. 26 differs from spectrometer 50B shown in Fig. 23 in that specific wavelength detector 20 is arranged on substrate 5 to the left of light output unit 4 (negative side of the Y axis in the figure). This change in arrangement is made in response to the specific wavelength λs being set to the longer wavelength side than the maximum wavelength λx of the measurement wavelength range. In other words, specific wavelength detector 20 is arranged at a position where light of specific wavelength λs is collected when light of maximum wavelength λx passes through light output unit 4.

[0070] In particular, when the maximum wavelength λx in the measurement wavelength range is 2000 nm or less, a specific wavelength λs' of higher-order diffracted light may be detected at the focusing position of the specific wavelength λs. While the λm, λx, and λs described above are first-order diffracted light, due to the principles of diffraction, second-order diffracted light, with a wavelength half that of the first-order diffracted light, is diffracted and superimposed on the first-order diffracted light. For example, if the specific wavelength λs is 2000 nm, second-order diffracted light with a wavelength of 1000 nm, where λs' = λs / 2, is focused at the same position as the focusing position of the first-order diffracted light. Therefore, detecting second-order diffracted light with wavelength λs' allows the use of a less expensive Si photodiode, thereby achieving further cost reductions.

[0071] The specific wavelength detector 20 described in the second embodiment is applicable to all of the spectrometers 10A to 10I described in the first embodiment.

[0072] An analytical device may be configured by using any of the spectrometers described in each embodiment together with a light source. In this analytical device, for example, a light source irradiates a measurement light onto an object to be measured. Then, a spectrometer separates the measurement light diffusely reflected by the object to be measured into wavelengths, and detects the measurement light for each wavelength obtained thereby. This allows the analytical device to obtain a spectrum for each wavelength that is characteristic of the molecular structure of the object to be measured. A wavelength-tunable light source may be configured by using any of the spectrometers described in each embodiment together with a light source. In this way, an analytical device and a wavelength-tunable light source using any of the spectrometers of each embodiment can be realized to be small and inexpensive, as the spectrometer is small and inexpensive.

[0073] FIG. 28 is a conceptual diagram illustrating the configuration of a spectroscopic measurement device 70 using a spectrometer 10A according to the first embodiment of the present invention. The spectroscopic measurement device 70 illustrated in FIG. 28 differs from the spectrometer 10A illustrated in FIG. 1 in that a photodetector 30 is installed outside the light output unit 4 and a light source 31 is further provided. In the spectroscopic measurement device 70, light emitted from the light source 31 is irradiated onto the object under test 90, and the light reflected by the object under test 90 enters the spectrometer 10A through the light input unit 1. The light diffracted by the concave diffraction grating 2 is reflected by the movable light reflector 3, emitted from the light output unit 4 according to the angle of the movable light reflector 3, and then detected by the detector 30. This enables the spectroscopic measurement device 70 to obtain an absorption spectrum of the object under test 90. The detailed operating principle of the spectroscopic measurement device 70 is the same as that described above, and therefore will not be described here.

[0074] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0075] 1 Light incidence part (light incidence means) 2. Concave diffraction grating (diffraction grating) 3 Movable light reflecting section (reflecting means) 4 Light emitting part (light emitting means) 5 Substrate (second substrate) 6 Substrate (first substrate) 7. Drive circuit (drive means) 8 Beam section 10A~10I spectrometer 11 Light reflection unit 14 Resin layer 15 Reflective material 17 Spacer (intervening member) 18 Light detection unit (light detection means) 19 Substrate (third substrate) 20 Specific wavelength detector (specific wavelength detection means) 21 Photodetector (photodetector section) 22 Bandpass Filter 23 Light blocking material 24 Light emitting section (second light emitting means) 50A~50E Spectrometer [Prior art documents] [Patent documents]

[0076] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-148485

Claims

1. a light input means for inputting light from outside; a diffraction grating that wavelength-disperses the light incident by the light incident means; a reflecting means having a reflecting surface that reflects the light that has been wavelength-dispersed by the diffraction grating, the inclination of the reflecting surface being variable; A spectrometer comprising:

2. a driving means for driving the reflecting means to control the inclination of the reflecting surface; 10. The spectrometer of claim 1, further comprising:

3. a light emitting means for emitting the light reflected by the reflecting means to the outside; 3. The spectrometer according to claim 1, further comprising:

4. The light emitting means and the diffraction grating are formed on the same substrate.

4. The spectrometer according to claim 3.

5. The light incident means and the reflecting means are formed on the same substrate.

5. The spectrometer according to claim 1, wherein the first and second wavelengths are different from each other.

6. The light emitting means and the light incident means are formed on the same substrate.

4. The spectrometer according to claim 3.

7. a first substrate and a second substrate; an interposition member disposed between the first substrate and the second substrate; the light incident means and the reflecting means are formed on the first substrate, the light emitting means and the diffraction grating are formed on the second substrate, Each of the first substrate and the second substrate is bonded to the interposition member.

4. The spectrometer according to claim 3.

8. a first substrate and a second substrate; Between the first substrate and the second substrate, a third substrate arranged non-parallel to the plate; Furthermore, the reflecting means is formed on the first substrate, the diffraction grating is formed on the second substrate; the light input means and the light output means are formed on the third substrate, Each of the first substrate and the second substrate is bonded to the third substrate.

4. The spectrometer according to claim 3.

9. The perpendicular line to the center of the diffraction grating is not perpendicular to the surface of the substrate on which the diffraction grating is formed. The diffraction grating is formed as follows:

9. The spectrometer according to claim 4, 5, 7 or 8.

10. a light detecting means for detecting the light emitted from the light emitting means; The spectrometer according to any one of claims 3 to 9, further comprising:

11. a light detecting means for detecting the light reflected by the reflecting means, instead of the light emitting means; 10. The spectrometer according to claim 3, further comprising:

12. A specific wavelength detection means for detecting light of a specific wavelength reflected by the reflecting means.

12. The spectrometer according to claim 1, further comprising:

13. The specific wavelength detecting means and the diffraction grating are formed on the same substrate.

13. The spectrometer of claim 12.

14. The specific wavelength detecting means is configured to include a light detecting unit and a bandpass filter, The photodetector and the bandpass filter are monolithically formed on the same substrate. are 14. The spectrometer according to claim 12 or 13.

15. The light reflected by the reflecting means is directed to the specific wavelength detecting means provided externally. a second light emitting means for emitting light The spectrometer of claim 12 further comprising:

16. The second light emitting means and the diffraction grating are formed on the same substrate.

16. The spectrometer of claim 15.

17. the time interval between detection signals of the light of the specific wavelength detected by the specific wavelength detection means By controlling the angle of the reflecting means to be constant, the tilt range of the reflecting means is controlled to be constant.

17. The spectrometer according to any one of claims 12 to 16.

18. The order of the light detected by the light detection means and the order of the light detected by the specific wavelength detection means The order of the light of the specific wavelength is different from 18. The spectrometer according to any one of claims 12 to 17.

19. A light source and A spectrometer according to any one of claims 1 to 18. An analytical device comprising:

20. A light source and The spectrometer according to any one of claims 1 to 9 and 12 to 17. A wavelength-tunable light source comprising:

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