Spectroscopic and analytical equipment

Abstract

To provide a spectroscope that has improved spectroscopic accuracy.SOLUTION: A spectroscope has: light incident means 1 that causes light from an outside to be incident through a first light passage part 11; a diffraction grating 2 that performs wavelength dispersion for the light made incident by the light incident means; reflecting means 3 that has a reflecting surface 32 reflecting the light for which wavelength dispersion is performed by the diffraction grating, wherein an inclination of the reflecting surface is variable; and light emission means 4 that emits partial light of rays of light with different wavelengths included in the wavelength dispersed light reflected by the reflecting means to the outside through a second light passage part 41, and the spectroscope satisfies a following formula (1) and a formula (2). (1) |θr|<|θm|, (2) |θr|<|θM|. (θm represents an incident angle at which light with a minimum wavelength in the wavelength dispersed light is incident on the second light passage part, θM represents an incident angle at which light with a maximum wavelength in the wavelength dispersed light is incident on the second light passage part, and θr represents an incident angle at which light with a wavelength selected from a range between the minimum wavelength and the maximum wavelength is incident on the second light passage part.)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 an optical spectrum for each wavelength.

[0003] A spectrometer has been disclosed that uses a confocal optical system to collect light reflected by a reflecting means with a variable tilt of the reflecting surface, disperses the collected light in different directions for each wavelength using a diffraction grating, and emits only light of some wavelengths from the wavelength-dispersed light using a mirror with slits (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, the light utilization efficiency and the intensity of stray light emitted from the light emitting means may change depending on the angle of incidence of light of different wavelengths contained in the wavelength-dispersed light that enters the light emitting means, such as a mirror with a slit. When the light utilization efficiency and the intensity of stray light change, the spectroscopic accuracy of the spectroscope decreases.

[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 improve the spectroscopic accuracy of a spectrometer. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the spectrometer of the present invention has a light incident means that incidents light from outside through a first light passing portion, a diffraction grating that wavelength-disperses the light incident by the light incident means, a reflecting means that has a reflecting surface that reflects the wavelength-dispersed light by the diffraction grating and the inclination of the reflecting surface is variable, and a light emitting means that emits a portion of light of different wavelengths contained in the wavelength-dispersed light reflected by the reflecting means to the outside through a second light passing portion, and satisfies the conditions of the following equations (1) and (2). |θr|<|θm| (1) |θr|<|θM| (2) (λm represents the minimum wavelength in the wavelength-dispersed light, λM represents the maximum wavelength in the wavelength-dispersed light, λr represents a wavelength selected from the range between λm and λM among the different wavelengths in the wavelength-dispersed light, θm represents the angle of incidence at which light of wavelength λm is incident on the second light passing section, θM represents the angle of incidence at which light of wavelength λM is incident on the second light passing section, and θr represents the angle of incidence at which light of wavelength λr is incident on the second light passing section.) [Effects of the Invention]

[0007] According to the present invention, the spectroscopic accuracy of the spectrometer can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view illustrating an example of the overall configuration of a spectrometer according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along the line II-II in FIG. [Figure 3] 3 is a diagram illustrating an example of the arrangement of a light emitting unit and a light detecting unit according to the first embodiment. FIG. [Figure 4] 4A is a diagram of the incident angle θM; FIG. 4B is a diagram of the incident angle θr; and FIG. 4C is a diagram of the incident angle θm. [Figure 5]5A is a diagram of the incident angle θM; FIG. 5B is a diagram of the incident angle θr; and FIG. 5C is a diagram of the incident angle θm. [Figure 6] 6A and 6B are diagrams illustrating incident angles to a light emitting portion, where FIG. 6A is a diagram of incident angle θM, FIG. 6B is a diagram of incident angle θr, and FIG. 6C is a diagram of incident angle θm. [Figure 7] FIG. 1 is a first diagram showing an example of change in light use efficiency depending on the angle of incidence. [Figure 8] FIG. 2 is a second diagram showing an example of change in light utilization efficiency depending on the incident angle. [Figure 9] FIG. 3 is a third diagram showing an example of change in light utilization efficiency depending on the incident angle. [Figure 10] 10A and 10B are diagrams illustrating a projected image of a light incident portion according to the second embodiment. [Figure 11] 10A and 10B are diagrams illustrating a projected image of a light emitting portion according to the second embodiment. [Figure 12] 10 is a cross-sectional view of a light entrance portion and a light exit portion according to a third embodiment. FIG. [Figure 13] 10 is a cross-sectional view of a light entrance portion and a light exit portion according to a first modified example. FIG. [Figure 14] FIG. 10 is a cross-sectional view of a light entrance portion and a light exit portion according to a second modified example. [Figure 15] 10A and 10B are diagrams illustrating the intensity of reflected light at a non-light passing portion according to the third embodiment. [Figure 16] 10A and 10B are diagrams illustrating reflection on the inner wall of a light transmitting portion according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0010] The embodiments described below exemplify spectrometers and analytical devices for embodying the technical concepts of the present disclosure, and are not intended to limit the present disclosure to the following embodiments. The dimensions, materials, shapes, relative positions, and other details of the components described below are intended for illustrative purposes only, unless otherwise specified. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity.

[0011] [Embodiment] <Example of overall configuration of spectrometer 10> 1 is a perspective view illustrating the overall configuration of a spectrometer 10 according to an embodiment. The spectrometer 10 includes a light input unit 1, a concave diffraction grating 2, a movable light reflector 3, a light output unit 4, a substrate 5, and a light detector 6.

[0012] The light incident section 1 is an example of a light incident means that allows light Li from the outside to be incident through the first light passing section 11. The area of ​​the light incident section 1 other than the first light passing section 11 constitutes a first non-light passing section 12 that does not allow light Li to pass through.

[0013] The first light passing portion 11 has, for example, a pinhole shape, a slit shape, or the like, and is provided to determine the incident position of light and to improve wavelength resolution.

[0014] The concave diffraction grating 2 is an example of a diffraction grating that wavelength-disperses light Li incident through the light incident portion 1. The concave diffraction grating 2 is formed on a substrate 5. The concave diffraction grating 2 diffracts the light Li to wavelength-disperse it, and reflects wavelength-dispersed light Ld toward the movable light reflector 3. Light of different wavelengths contained in the wavelength-dispersed light Ld propagates while converging, enters different positions on a reflection line 33 on the reflection surface 32, and is reflected by the reflection surface 32.

[0015] The substrate 5 may be made of, but is not limited to, a semiconductor, glass, metal, resin, etc. The concave diffraction grating 2 may be formed directly on the substrate 5, or may be formed on a thin film layer, such as a resin layer, formed on the substrate 5.

[0016] The movable light reflector 3 has a reflecting surface 32 that reflects the wavelength-dispersed light Ld caused by the concave diffraction grating 2, and is an example of a reflecting means in which the inclination of the reflecting surface is variable. The movable light reflector 3 reflects the wavelength-dispersed light Ld caused by the concave diffraction grating 2 toward the light emitting portion 4 by the reflecting surface 32.

[0017] The movable light reflecting portion 3 has a swing axis 31. The movable light reflecting portion 3 swings around the swing axis 31, thereby changing the inclination of a reflecting surface 32 that reflects the wavelength dispersed light Ld.

[0018] The movable light reflecting unit 3 can be formed thin and small on a semiconductor substrate using, for example, a semiconductor process, a MEMS (Micro Electro Mechanical Systems) process, or the like. Furthermore, by forming the movable light reflecting unit 3 on a semiconductor substrate, a driving element unit, such as a piezoelectric drive, an electrostatic drive, or an electromagnetic drive, can be monolithically formed on the semiconductor substrate. This allows the spectrometer 10 to drive the movable light reflecting unit 3 without using an external driving device such as a motor, thereby enabling further miniaturization. However, the substrate on which the movable light reflecting unit 3 is formed is not limited to a semiconductor, and may be glass, metal, resin, or the like.

[0019] The light emitting unit 4 is an example of a light emitting means that emits a portion of the light of different wavelengths contained in the wavelength dispersed light Ld reflected by the movable light reflecting unit 3 to the outside through the second light passing portion 41. The portion of the light of different wavelengths contained in the wavelength dispersed light Ld is emitted to the outside through the second light passing portion 41 at its approximate focal position. The area of ​​the light emitting unit 4 other than the second light passing portion 41 constitutes a second light non-passing portion 42 that does not pass the wavelength dispersed light Ld.

[0020] The second light passing portion 41 has, for example, a pinhole shape, a slit shape, or the like, and is provided to determine the emission position of some of the light of different wavelengths contained in the wavelength-dispersed light Ld, and to improve the wavelength resolution.

[0021] The light beams with different wavelengths contained in the wavelength dispersed light Ld are reflected at different positions on the reflection line 33 on the reflecting surface 32 and enter the light emitting section 4 at different positions on the emission line 43.

[0022] By changing the tilt of the reflecting surface 32 of the movable light reflecting portion 3 around the swing axis 31, the incident positions on the emission line 43 of the light beams of different wavelengths contained in the wavelength dispersed light Ld change.

[0023] Of the light of different wavelengths contained in the wavelength-dispersed light Ld, light that is incident on the position of the second light passing portion 41 is output through the second light passing portion 41. The light output portion 4 can output light of a wavelength that is contained in the wavelength-dispersed light Ld and that is determined by the oscillation angle of the movable light reflector 3 through the second light passing portion 41.

[0024] 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, using a semiconductor as the substrate material is preferable because the light incident portion 1 and the light emitting portion 4 can be formed with high precision and low cost using a semiconductor process, MEMS process, etc.

[0025] The light detection unit 6 is an example of a light detection means that detects the light emitted from the light emission unit 4. For example, a photodiode can be used for the light detection unit 6. When light Li in the near-infrared region is to be separated, an InGaAs photodiode is preferable.

[0026] In the spectrometer 10, the above-mentioned components are arranged in 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.

[0027] <Configuration example of concave diffraction grating 2> FIG. 2 is a diagram illustrating the configuration of the concave diffraction grating 2, and is a cross-sectional view taken along the line II-II in FIG.

[0028] As shown in Fig. 2, the concave diffraction grating 2 has 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.

[0029] The concave diffraction grating 2 may have grooves with a cross-sectional shape such as a rectangular shape, a sinusoidal wave shape, or a sawtooth wave shape.

[0030] The concave diffraction grating 2 may not have a reflecting member 15. Furthermore, the configuration of the concave diffraction grating 2 is not limited to that illustrated in FIG. 2 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 be obtained by using a planar diffraction grating instead of the concave diffraction grating 2. In this case, a complex device configuration (such as a collimating optical system for collimating light before and after the planar diffraction grating) that would be required when adopting a configuration in which the inclination of the planar diffraction grating is changed is not necessary.

[0031] In the concave diffraction grating 2, a thin-film resin layer may be formed on the concave curved surface formed on the upper surface of the substrate 5, and the diffraction grating may be formed on this resin layer. In this case, in order to improve reflectance, it is preferable to form a reflective member made of a metal material such as Al, Ag, Au, or Pt on the surface of the diffraction grating formed on the resin layer.

[0032] <Example of arrangement of light emitting unit 4 and light detecting unit 6> FIG. 3 is a diagram illustrating an example of the arrangement of the light emitting unit 4 and the light detecting unit 6, and is a side view of the light emitting unit 4 and the light detecting unit 6. As shown in FIG.

[0033] 3, the light emitting unit 4 is provided so as to be in contact with the light detecting unit 6. The light detecting unit 6 supports the light emitting unit 4 by adhering the light emitting unit 4 with an adhesive member, a sticky member, or the like.

[0034] The adhesive or pressure-sensitive adhesive material that bonds the light emitting unit 4 and the light detecting unit 6 can be made of a material containing a thermoplastic resin, a thermosetting resin, a rubber or elastomer, a silicone, or a knitted silicone. Since the temperature of the light detecting unit 6 may rise due to power consumption, it is desirable that the adhesive or pressure-sensitive adhesive material be an adhesive or pressure-sensitive adhesive material with excellent stress relaxation properties that suppresses thermal deformation of the light emitting unit 4. The light detecting unit 6 may be adhesively supported by the light emitting unit 4 in a state close to the light emitting unit 4 via a member other than the adhesive material, without contacting the light emitting unit 4.

[0035] The light detection unit 6 includes a light receiving window 61. The emitted light that has passed through the second light passing portion 41 of the light exit unit 4 is detected by the light detection unit 6 through the light receiving window 61.

[0036] The incident angle θr represents the angle at which light Lr having a wavelength λr as a predetermined wavelength, among the light of different wavelengths contained in the wavelength-dispersed light Ld, is incident on the light emitting portion 4. More specifically, the incident angle θr is the angle formed between the light-receiving central axis 60, which passes through approximately the center of the light-receiving window 61 and extends in an approximately normal direction to the light-receiving window 61, and the optical axis Lr1, which is the central axis of the light Lr. The optical axis Lr1 can also be said to be the principal ray of the light Lr.

[0037] Here, if the light emitting section and the light detecting section are spaced apart along the light receiving central axis 60, when the incident angle θr is large, the distance between the incident position of the light Lr that has passed through the second light passing section into the light detecting section and the light receiving central axis 60 becomes long, and the light Lr may not enter the light receiving window of the light detecting section and may not be detected by the light detecting section.

[0038] In this embodiment, the light detection unit 6 is provided so as to be in contact with or close to the light emission unit 4, so even when the incident angle θr is large, the incident position of the light Lr on the light detection unit 6 can be brought close to the light-receiving central axis 60. As a result, even when the incident angle θr is large, the light Lr is incident on the light-receiving window 61, and the light detection unit 6 can detect the light Lr.

[0039] Furthermore, if the light emitting portion and the light detecting portion are spaced apart along the light-receiving central axis 60 and are supported by separate members, the relative position between the light emitting portion and the light detecting portion is likely to fluctuate. In this embodiment, the light detecting portion 6 supports the light emitting portion 4, so that fluctuation in the relative position between the light emitting portion 4 and the light detecting portion 6 can be suppressed.

[0040] <Relationship between the angle of incidence on the light emitting portion 4, the light utilization efficiency, and stray light> 4 to 6 are diagrams illustrating the angle of incidence on the light emitting portion 4. FIG. 4 is FIG. 1, where FIG. 4(a) is a diagram of the angle of incidence θM, FIG. 4(b) is a diagram of the angle of incidence θr, and FIG. 4(c) is a diagram of the angle of incidence θm. FIG. 5 is FIG. 2, where FIG. 5(a) is a diagram of the angle of incidence θM, FIG. 5(b) is a diagram of the angle of incidence θr, and FIG. 5(c) is a diagram of the angle of incidence θm. FIG. 6 is FIG. 3, where FIG. 6(a) is a diagram of the angle of incidence θM, FIG. 6(b) is a diagram of the angle of incidence θr, and FIG. 6(c) is a diagram of the angle of incidence θm.

[0041] In this embodiment, the relationship between the angles of incidence θM, θr, and θm is expressed by the following equations (1) and (2). |θr|<|θm| (1) |θr|<|θM| (2)

[0042] Here, λm represents the minimum wavelength of the wavelength-dispersed light Ld. λM represents the maximum wavelength of the wavelength-dispersed light Ld. λr represents a wavelength selected from the range between λm and λM among the different wavelengths in the wavelength-dispersed light Ld. Furthermore, θm represents the angle of incidence at which light Lm of wavelength λm enters the second light passing section 41. θM represents the angle of incidence at which light LM of wavelength λM enters the second light passing section 41. θr represents the angle of incidence at which light Lr of wavelength λr enters the second light passing section 41.

[0043] More specifically, the incident angle θm is the angle formed between the above-mentioned light-receiving central axis 60 and the optical axis Lm1, which is the central axis of light Lm. The incident angle θM is the angle formed between the light-receiving central axis 60 and the optical axis LM1, which is the central axis of light LM. The incident angle θr is the angle formed between the light-receiving central axis 60 and the optical axis Lr1, which is the central axis of light Lr. The optical axis Lm1 can also be referred to as the chief ray of light Lm, the optical axis LM1 as the chief ray of light LM, and the optical axis Lr1 as the chief ray of light Lr.

[0044] In Figures 4 to 6, the arrangement is such that when the tilt angle of the reflecting surface 32 of the movable light reflecting part 3 around the oscillation axis 31 is small, the light LM passes through the second light passing part 41, and when the tilt angle of the reflecting surface 32 around the oscillation axis 31 is large, the light Lm passes through the second light passing part 41.

[0045] As shown in Figure 4, depending on the change in inclination of the reflecting surface 32 of the movable light reflecting section 3, the incident position of each of the different wavelengths of light contained in the wavelength-dispersed light Ld on the light emitting section 4 changes, and the incident angle on the second light passing section 41 also changes.

[0046] The amount of light passing through the second light passing portion 41 varies depending on the angle of incidence. As the angle of incidence increases, the amount of light that cannot pass through the second light passing portion 41 increases, and the light utilization efficiency of the spectroscope 10 decreases.

[0047] By satisfying the conditions of the above formulas (1) and (2), the differences between the angles of incidence θm, θM, and θr become small, and the light utilization efficiency of the lights Lm, LM, and Lr can be improved.

[0048] 5 and 6 show the relationship between the incident angles θm, θM, and θr when the inclination of the light emitting portion 4 is changed compared to FIG. 4. In the example of FIG. 5, by arranging the incident angle θM to be approximately 0 degrees, the relationship |θM|<|θr|<|θm| is established. In the example of FIG. 6, by arranging the incident angle θm to be approximately 0 degrees, the relationship |θm|<|θr|<|θM| is established.

[0049] Here, among the wavelength-dispersed light Ld that has entered the light emitting unit 4, light that cannot pass through the second light passing portion 41 may become stray light after being reflected by the second non-light passing portion 42 of the light emitting unit 4. Note that stray light refers to light that does not contribute to the spectrometry by the spectroscope 10.

[0050] In the arrangement shown in Figure 4, most of the light reflected by the second non-light-passing portion 42 travels back along the optical path it came from and is guided in the order of the movable light reflecting portion 3, the concave diffraction grating 2, and the light incident portion 1, and some of the light is reflected by the first non-light-passing portion 12 in the light incident portion 1.

[0051] The light reflected by the first non-light-passing portion 12 is guided again to the concave diffraction grating 2, the movable light reflecting portion 3 and the second non-light-passing portion 42 in that order, and a portion of the light is reflected by the second non-light-passing portion 42.

[0052] As described above, the light reflected by the second non-light passing portion 42 is multiple-reflected between the light exit portion 4 and the light entrance portion 1. For example, if the reflectance of each of the first non-light passing portion 12 and the second non-light passing portion 42 is reduced, the multiple-reflected light will be extinguished as the number of reflections in the multiple reflections increases, and stray light due to this multiple-reflected light will be suppressed.

[0053] On the other hand, in the arrangement shown in Figure 5, the incident angles θm, θM, and θr have the relationship |θM|<|θr|<|θm|, so the light Lm reflected by the second non-light-passing portion 42 does not travel back along the optical path it came from, and is likely to become stray light by being reflected by the support members that support the light incident portion 1, the concave diffraction grating 2, the movable light reflecting portion 3, and the light emitting portion 4, etc.

[0054] Similarly, in the case of the arrangement shown in Figure 6, the incident angles θm, θM, and θr are in the relationship |θm|<|θr|<|θM|, so the light LM reflected by the second non-light-passing portion 42 does not travel back along the optical path it came from, and is likely to become stray light by being reflected by the support members that support the light incident portion 1, the concave diffraction grating 2, the movable light reflecting portion 3, and the light emitting portion 4, etc.

[0055] From the above, in the arrangement shown in FIG. 4, if the conditions of the above expressions (1) and (2) are satisfied, the effect of suppressing the occurrence of stray light is enhanced.

[0056] <Simulation results of light utilization efficiency> 7 to 9 are diagrams showing examples of changes in light use efficiency according to the angle of incidence on the second light passing portion 41, with Fig. 7 being Fig. 1, Fig. 8 being Fig. 2, and Fig. 9 being Fig. 3. All of Fig. 7 to Fig. 9 show the results of calculating the light use efficiency according to the angle of incidence through a simulation using lighting analysis software. In each diagram, the horizontal axis represents the angle of incidence on the second light passing portion 41, and the vertical axis represents the normalized light use efficiency.

[0057] The simulation results shown in each figure are for an arrangement in which light LM passes through the second light passing section 41 when the tilt angle of the reflecting surface 32 of the movable light reflecting section 3 around the oscillation axis 31 is small, and light Lm passes through the second light passing section 41 when the tilt angle of the reflecting surface 32 around the oscillation axis 31 is large.

[0058] FIG. 7 shows the case where equations (1) and (2) are satisfied, FIG. 8 shows the case where the relationship |θM|<|θr|<|θm| is satisfied, and FIG. 9 shows the case where the relationship |θm|<|θr|<|θM| is satisfied.

[0059] The ratio of the minimum to the maximum light utilization efficiency was approximately 89% in Figure 7, approximately 81% in Figure 8, and approximately 74% in Figure 9. This shows that excellent light utilization efficiency can be obtained by satisfying the conditions of equations (1) and (2) above.

[0060] <Action and effect of the spectrometer 10> As described above, the spectrometer 10 includes a light incident section 1 (light incident means) that allows external light Li to enter through the first light passing section 11, and a concave diffraction grating 2 (diffraction grating) that wavelength-disperses the light Li incident by the light incident section 1. The spectrometer 10 also includes a movable light reflector 3 (reflection means) that has a reflecting surface 32 that reflects wavelength-dispersed light Ld by the concave diffraction grating 2 and whose inclination is variable, and a light exit section 4 (light exit means) that exits a portion of the light of different wavelengths contained in the wavelength-dispersed light Ld reflected by the movable light reflector 3 to the outside through the second light passing section 41. The spectrometer 10 satisfies the conditions of the above formulas (1) and (2).

[0061] By satisfying the conditions of the above formulas (1) and (2), the differences between the incident angles θm, θM, and θr become small, and therefore, in the spectrometer 10, the light utilization efficiency of the light Lm, LM, and Lr emitted from the light emitting unit 4 is improved. Since the signal-to-noise ratio in the light detecting unit 6 increases due to the improved light utilization efficiency, the spectroscopic accuracy of the spectrometer 10 can be improved in this embodiment.

[0062] Furthermore, by satisfying the conditions of the above formulas (1) and (2), the light reflected by the second non-light passing portion 42 is multiple-reflected between the light exit portion 4 and the light entrance portion 1. For this reason, for example, if the reflectance of each of the first non-light passing portion 12 and the second non-light passing portion 42 is reduced, the multiple-reflected light will be extinguished as the number of reflections in the multiple reflections increases. Therefore, in the spectrometer 10, stray light due to light reflected by support members and the like that support the light entrance portion 1, the concave diffraction grating 2, the movable light reflecting portion 3, and the light exit portion 4 can be suppressed, and the signal-to-noise ratio in the light detection portion 6 can be increased.

[0063] Furthermore, in this embodiment, the spectrometer 10 has a light detection unit 6 (light detection means) that detects light emitted from the light emission unit 4, and the light detection unit 6 is provided so as to be in contact with or in close proximity to the light emission unit 4. This makes it possible to suppress light that is not incident on the light receiving window 61 and therefore not detected by the light detection unit 6, even when the incident angle θr is large, thereby improving the light utilization efficiency and the spectroscopic accuracy of the spectrometer 10.

[0064] Furthermore, in this embodiment, the light detection unit 6 supports the light emission unit 4, so that fluctuations in the relative positions between the light emission unit 4 and the light detection unit 6 can be suppressed, and the spectroscopic accuracy of the spectrometer 10 can be improved.

[0065] [Second embodiment] Next, a second embodiment of the spectrometer 10 will be described. Note that the same components as those in the first embodiment are given the same reference numerals, and redundant explanations will be omitted as appropriate. This also applies to the following embodiments.

[0066] <Example of the relationship between the shape of the first light passing portion 11 and the shape of the second light passing portion 41> Fig. 10 is a diagram illustrating a projected image 1s of the light entrance portion 1 according to this embodiment. Fig. 11 is a diagram illustrating a projected image 4s of the light exit portion 4 according to this embodiment.

[0067] 10 shows how light Li passes through the first light passing portion 11 of the light incident portion 1. A projected image 1s is a projected image of the first light passing portion 11 projected onto a plane Pi that is perpendicular to the chief ray Li0 of light Li passing through the first light passing portion 11.

[0068] 11 shows how light Lr having a wavelength λr, among light of different wavelengths contained in the wavelength-dispersed light Ld, passes through the second light passing portion 41 of the light emitting portion 4. A projected image 4s is a projected image of the second light passing portion 41 projected onto a plane Pr orthogonal to the chief ray Lr0 of the light Lr passing through the second light passing portion 41.

[0069] In this embodiment, the spectrometer 10 is configured so that the shape of the projected image 1s is equal to the shape of the projected image 4s. This configuration suppresses a decrease in the amount of light Li incident from the light incident unit 1, and allows the light detecting unit 6 to detect the light Lr that has passed through the second light passing unit 41 with high efficiency. As a result, in this embodiment, the light utilization efficiency of the spectrometer 10 can be improved, and the spectroscopic accuracy of the spectrometer 10 can be improved.

[0070] In this embodiment, the first light passing portion 11 and the second light passing portion 41 are in a conjugate relationship for light of a predetermined wavelength within the range of wavelengths λm and λM. As the tilt of the reflecting surface 32 of the movable light reflector 3 changes, the focal position of light that reaches the light emitting portion 4 changes depending on the wavelength, which may result in a decrease in wavelength resolution. In this embodiment, by making the first light passing portion 11 and the second light passing portion 41 conjugate with each other for light of a predetermined wavelength, it is possible to suppress the amount of change in the focal position for light of the predetermined wavelength, and to suppress a decrease in wavelength resolution.

[0071] When the first light passing portion 11 and the second light passing portion 41 are formed in a slit shape, the further away from the center in the longitudinal direction of the slit, the more likely the focal position is to change due to aberration in the normal direction of the first light passing portion 11 and the second light passing portion 41. For this reason, it is preferable to form the concave diffraction grating 2 in an aspherical shape, thereby establishing a conjugate relationship between the first light passing portion 11 and the second light passing portion 41.

[0072] [Third embodiment] Next, a third embodiment of the spectrometer 10 will be described.

[0073] Fig. 12 is a cross-sectional view illustrating the configuration of the light incident section 1 and the light emitting section 4 according to this embodiment. Since the light incident section 1 and the light emitting section 4 have the same configuration, the same reference numerals are used in Fig. 12. This also applies to Figs. 13 and 14 below.

[0074] As shown in FIG. 12, the light incident portion 1 includes a nickel (Ni) substrate 111, a black chromium (Cr) film 112, and a first light passing portion 11.

[0075] The black chrome film 112 is laminated on the surface of the nickel substrate 111 corresponding to the inside of the spectrometer 10, and constitutes the first non-light passing portion 12. The first light passing portion 12 is formed so as to penetrate the nickel substrate 111 and the black chrome film 112.

[0076] The light emitting portion 4 includes a nickel substrate 411, a black chrome film 412, and a second light passing portion 41.

[0077] The black chrome film 412 is laminated on the surface of the nickel substrate 411 corresponding to the inside of the spectrometer 10, and constitutes the second non-light passing portion 42. The second light passing portion 41 is formed so as to penetrate the nickel substrate 411 and the black chrome film 412.

[0078] The light incident section 1 and the light exit section 4 are each formed by electroforming. Electroforming is a processing method in which metal ions are electrodeposited onto a base material to form a shape. The light incident section 1 and the light exit section 4 are formed by electrodepositing chromium, which is a metal ion, onto a nickel substrate, which serves as the base material.

[0079] By forming the light incident portion 1 and the light exit portion 4 by electroforming, it is possible to form thin light incident portion 1 and light exit portion 4. As a result, in this embodiment, it is possible to reduce light reflection on the inner walls of first light passing portion 11 and second light passing portion 41 and suppress stray light.

[0080] Nickel is suitable as a material for the substrates of the light entrance part 1 and the light exit part 4 because it can be easily processed by electroforming.

[0081] If the substrates of the light incident portion 1 and the light exit portion 4 include a black nickel material such as a tin-nickel alloy, a nickel-zinc alloy, or a tin-nickel-copper alloy, the reflectance of the light incident portion 1 and the light exit portion 4 can be reduced, and for example, reflection on the inner walls of the first light passing portion 11 and the second light passing portion 41 can be reduced. This makes it possible to suppress stray light in the spectrometer 10.

[0082] Since the light incident portion 1 includes the black chrome film 112 and the light exit portion 4 includes the black chrome film 412, when multiple reflections occur between the light incident portion 1 and the light exit portion 4, the multiple reflected light is extinguished as the number of multiple reflections increases. This makes it possible to suppress stray light due to the multiple reflected light.

[0083] FIG. 13 is a cross-sectional view illustrating the configuration of a light incident portion 1a and a light emitting portion 4a according to the first modified example.

[0084] As shown in FIG. 13, the light incident portion 1a includes a silicon (Si) substrate 111a, a vacuum-deposited light-shielding film 112a, and a first light passing portion 11.

[0085] The vacuum-deposited light-shielding film 112a is formed by laminating on the surface of the silicon substrate 111a corresponding to the inside of the spectrometer 10, and constitutes the first non-light-passing portion 12. The first light-passing portion 11 is formed so as to penetrate the silicon substrate 111a and the vacuum-deposited light-shielding film 112a.

[0086] The light emitting portion 4a includes a silicon substrate 411a, a vacuum-deposited light-shielding film 412a, and a second light passing portion 41.

[0087] The vacuum-deposited light-shielding film 412a is formed by laminating on the surface of the silicon substrate 411a corresponding to the inside of the spectrometer 10, and constitutes the second non-light-passing portion 42. The second light-passing portion 41 is formed so as to penetrate the silicon substrate 411a and the vacuum-deposited light-shielding film 412a.

[0088] The vacuum deposition light-shielding films 112a and 412a are each an example of a first reflective film, and are low-reflectivity films. The low-reflectivity film can be a granular metal film or the like that can be formed by vacuum deposition or plating.

[0089] By configuring the light incident portion 1a and the light emitting portion 4a to include the silicon substrate 411a, it becomes possible to manufacture the light incident portion 1a and the light emitting portion 4a with high precision and at low cost using semiconductor processes, MEMS processes, etc. Other effects are similar to those of the light incident portion 1 and the light emitting portion 4.

[0090] FIG. 14 is a cross-sectional view illustrating the configuration of a light incident portion 1b and a light emitting portion 4b according to the second modified example.

[0091] As shown in FIG. 14, the light incident portion 1b includes a glass substrate 111b, a chromium / chromium oxide film 112b, and a first light passing portion 11.

[0092] The chromium / chromium oxide film 112b is formed and laminated on the surface of the glass substrate 111b corresponding to the inside of the spectrometer 10, and constitutes the first non-light passing portion 12. The first light passing portion 11 is formed so as to penetrate the chromium / chromium oxide film 112b.

[0093] The light exit portion 4b includes a glass substrate 411b, a chromium / chromium oxide film 412b, and a second light passing portion 41.

[0094] The chromium / chromium oxide film 412b is formed by laminating on the surface of the glass substrate 411b corresponding to the inside of the spectrometer 10, and constitutes the second non-light passing portion 42. The second light passing portion 41 is formed so as to penetrate the chromium / chromium oxide film 412b.

[0095] The chromium / chromium oxide films 112b and 412b are examples of second reflective films, and are low-reflection films with low reflectivity. The low-reflection film can be a granular metal film that can be formed by vacuum deposition or plating. The low-reflection film can also be formed from an alternating laminate film of chromium film and silicon oxide film, or chromium film and chromium oxide film, etc.

[0096] By using glass substrates, the light entrance portion 1b and the light exit portion 4b can be manufactured inexpensively. Furthermore, by forming the first non-light-passing portion 12 and the second non-light-passing portion 42 by laminating multiple dielectric thin films, the light transmission characteristics of the light entrance portion 1b and the light exit portion 4b can be adjusted, and stray light can be reduced. Other effects are the same as those of the light entrance portion 1 and the light exit portion 4.

[0097] In this embodiment, any of the light incident portions 1, 1a, and 1b may be used as the light incident portion, and any of the light output portions 4, 4a, and 4b may be used as the light output portion. The light incident portions 1, 1a, and 1b and the light output portions 4, 4a, and 4b may also be used in appropriate combination.

[0098] In the following description, the light entrance portion 1 and the light exit portion 4 are taken as examples, but they may be replaced with the light entrance portion 1a or 1b, or the light exit portion 4a or 4b.

[0099] 15 is a diagram illustrating the intensity of reflected light at the first non-light passing portion 12 and the second non-light passing portion 42. The horizontal axis of FIG. 15 represents the normalized tilt of the reflecting surface 32, and the vertical axis represents the normalized amount of received light at the light detecting unit 6.

[0100] 15, solid line graph 151 represents the light intensity of main light received by the light detection unit 6. Dashed line graph 152 represents the light intensity received by the light detection unit 6 of light that has traveled back and forth once by multiple reflection between the light entrance unit 1, where the reflectance of the first non-light passing portion 12 is 90%, and the light exit unit 4, where the reflectance of the second non-light passing portion 42 is 90% (referred to as single-round trip light).

[0101] The dashed dotted line graph 153 represents the received light intensity by the light detection unit 6 of light that has traveled back and forth once by multiple reflection between the light entrance unit 1, where the reflectance of the first non-light passing portion 12 is 50%, and the light exit unit 4, where the reflectance of the second non-light passing portion 42 is 50%.

[0102] The dashed-dotted line graph 153 represents the intensity of light received by the light detection unit 6 after multiple reflections that make a round trip between the light entrance unit 1, where the reflectance of the first non-light-passing portion 12 is 30%, and the light exit unit 4, where the reflectance of the second non-light-passing portion 42 is 30%.

[0103] The main light and the one-time round trip light are lights of a predetermined wavelength within the range between wavelengths λm and λM.

[0104] The one-time round trip light is stray light because it is reflected by the reflecting surface 32 at an angle different from the appropriate angle and then detected by the light detection unit 6. The relative intensity of the one-time round trip light to the main light is 0.35 in graph 151, 0.11 in graph 152, and 0.04 in graph 153.

[0105] For example, in applications where the material of a substance is determined from its spectral reflectance using the spectroscope 10, determination is possible if the stray light relative to the main light is approximately 5% or less. Therefore, based on Fig. 15, it is preferable that the reflectance of both the first non-light passing portion 12 and the second non-light passing portion 42 be 30% or less for light of a predetermined wavelength within the range of wavelengths λm and λM. In this way, the light intensity of the light that makes a single round trip and is detected by the light detection unit 6 can be reduced to 5% or less, ensuring high spectroscopic accuracy using the spectroscope 10.

[0106] Fig. 16 is a diagram illustrating reflections on the inner walls of the first light passing portion 11 and the second light passing portion 41. Fig. 16 shows an enlarged view of the first light passing portion 11 in the light incident portion 1 and the second light passing portion 41 in the light exit portion 4.

[0107] 16, an inner wall 13 represents the inner wall of the first light passing portion 11, and an inner wall 44 represents the inner wall of the second light passing portion 41. A thickness t represents the thickness of each of the first light passing portion 11 and the second light passing portion 41.

[0108] The light reflected by the inner walls 13 and 44 becomes stray light because it is reflected by areas other than the effective area of ​​the concave diffraction grating 2. When the thickness t of each of the first light passing portion 11 and the second light passing portion 41 is set to 0.1 mm or less, the intensity of the light reflected by the inner walls 13 and 44 becomes sufficiently small compared to the intensity of the light used for spectroscopic analysis, thereby ensuring high spectroscopic accuracy by the spectrometer 10.

[0109] 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.

[0110] The spectrometer according to the embodiment can also be used in an analytical device, which identifies the resin type of an object by spectroscopically analyzing the spectrum obtained by the spectrometer, and sorts and recovers the object by resin type as a recyclable material. [Explanation of symbols]

[0111] 1. Light incident section (an example of light incident means) 1s projection image 11 1st light passage section 12 1st non-light passing section 13 Inner wall 2. Concave diffraction grating (an example of a diffraction grating) 3 Movable light reflecting unit (an example of reflecting means) 31 Oscillating shaft 32 Reflective surface 33 Reflective Line 4. Light emitting section (an example of a light emitting means) 4s projection image 41 Second light passage section 42 2nd non-light passing section 43 Exit Line 44 Inner wall 5. Substrate 6. Light detection unit (an example of a light detection means) 60 Light receiving center axis 61 Light receiving window 10 spectrometer 15 Reflective material 112a, 412a: Vacuum deposition light-shielding film (an example of a first reflective film) 112b, 412b Chromium / chromium oxide film (an example of a second reflective film) 151, 152, 153 graphs 411 Nickel substrate 411a Silicon substrate 411b Glass substrate Li, Lr, Lm, LM light Li0, Lr0 chief ray Lr1, Lm1, LM1 optical axis LD wavelength dispersion light θr, θm, θM incident angle λr, λm, λM wavelength Pi and Pr planes t thickness [Prior art documents] [Patent documents]

[0112] [Patent Document 1] Patent Gazette No. 5558927

Claims

1. a light incidence means for allowing external light to be incident through the first light passing portion; a diffraction grating that wavelength-disperses the light incident by the light incident means; a reflecting means having a reflecting surface that reflects wavelength-dispersed light caused by the diffraction grating, the inclination of the reflecting surface being variable; a light output unit that outputs a part of the light of different wavelengths included in the wavelength-dispersed light reflected by the reflecting unit to the outside through a second light passing portion, A spectrometer that satisfies the conditions of the following expressions (1) and (2): |θr|<|θm| ...(1) |θr|<|θM| ...(2) (λm represents the minimum wavelength in the wavelength-dispersed light, λM represents the maximum wavelength in the wavelength-dispersed light, λr represents a wavelength selected from the range between λm and λM among the different wavelengths in the wavelength-dispersed light, θm represents the angle of incidence at which light of wavelength λm is incident on the second light passing portion, θM represents the angle of incidence at which light of wavelength λM is incident on the second light passing portion, and θr represents the angle of incidence at which light of wavelength λr is incident on the second light passing portion.)

2. further comprising a light detection means for detecting light emitted from the light emitting means, the light detection means is provided so as to be in contact with or in close proximity to the light emitting means; 10. The spectrometer of claim 1.

3. 3. The spectrometer of claim 2, wherein said light detecting means supports said light emitting means.

4. 4. The spectrometer according to claim 1, wherein a shape of a projected image of the first light passing portion projected onto a plane orthogonal to a chief ray of the light passing through the first light passing portion is equal to a shape of a projected image of the second light passing portion projected onto a plane orthogonal to a chief ray of the light emitted from the light emitting means.

5. 5. The spectrometer according to claim 1, wherein the first light passing portion and the second light passing portion are in a conjugate relationship with respect to light of a predetermined wavelength within a range between wavelengths λm and λM.

6. 6. The spectrometer according to claim 1, wherein the reflectance of the first non-light-passing portion of the light incident means and the reflectance of the second non-light-passing portion of the light output means are both 30% or less for light of a predetermined wavelength within a range between wavelengths λm and λM.

7. 7. The spectroscope according to claim 1, wherein the first light passing portion and the second light passing portion each have a thickness of 0.1 mm or less.

8. 8. The spectrometer according to claim 1, wherein the light input means and the light output means are each formed by an electroforming process.

9. 8. The spectrometer according to claim 1, wherein each of the light input means and the light output means includes a silicon substrate and a first reflective film formed on the silicon substrate.

10. 8. The spectrometer according to claim 1, wherein each of the light input means and the light output means includes a glass substrate and a second reflective film formed on the glass substrate.

11. An analytical device comprising the spectrometer according to any one of claims 1 to 10.

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