JP2011232129A - Light measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light measuring device capable of performing spectroscopic measurement with high accuracy.SOLUTION: A spectrometer 1 comprises an etalon for short-wavelength region 2A that extracts first wavelength light in a first measurement wavelength region, an etalon for long-wavelength region 2B that extracts second wavelength light in a second measurement wavelength region, a wavelength of which is longer than a wavelength of the first measurement wavelength region, an aperture for short-wavelength region 4A that adjusts the amount of light to be measured that is incident on the etalon for short-wavelength region 2A, an aperture for long-wavelength region 4B that adjusts the amount of the light to be measured that is incident on the etalon for long-wavelength region 2B, a photodetector for short-wavelength region 3A that receives the first wavelength light and outputs a detection signal, and a photodetector for long-wavelength region 3B that receives the second wavelength light and outputs a detection signal. The amount of the light passing through the aperture for short-wavelength region 4A is larger than the amount of the light passing through the aperture for long-wavelength region 4B.

Description

  The present invention relates to an optical measurement device that measures optical characteristics.

  2. Description of the Related Art Conventionally, a spectroscopic measurement device that measures optical characteristics (chromaticity, brightness, etc.) of each wavelength light of incident light is known (see, for example, Patent Document 1).

  The analyzer described in Patent Document 1 causes light emitted from a light source and reflected by a sample to enter a wavelength variable interference filter, and light transmitted through the wavelength variable interference filter is received by a photodiode (PD). And it is an apparatus which measures by detecting the electric current output from PD. In such an analyzer, by controlling the wavelength tunable interference filter, the light transmitted through the wavelength tunable interference filter can be varied, and light of a desired wavelength can be sequentially switched from the incident light and received by the PD. Become.

JP 2005-106753 A

  Here, FIG. 11 shows general spectral sensitivity characteristics of a silicon photodiode. As shown in FIG. 11, in a general PD, relative sensitivity to light in a short wavelength region is lower than light in a long wavelength region. For this reason, even if the light quantity of the short wavelength light and the light quantity of the long wavelength light are the same, the PD cannot sufficiently detect the short wavelength light, and the detection result that the light quantity of the short wavelength light is smaller is obtained. There is inconvenience to be issued. Therefore, the spectroscopic measurement apparatus as described in Patent Document 1 has a problem in that the accuracy of the measurement result in the short wavelength region is poor, and accurate measurement of optical characteristics with respect to incident light cannot be performed.

  In view of the above problems, an object of the present invention is to provide an optical measurement device capable of performing highly accurate spectroscopic measurement.

  The light measurement device of the present invention includes a first optical filter that extracts light having a first wavelength within a first measurement wavelength region in the measurement target light, and a wavelength that is greater than the first measurement wavelength region in the measurement target light. A second optical filter that extracts light of a second wavelength within a long second measurement wavelength region, a first light amount adjustment unit that adjusts the amount of light of the measurement target light incident on the first optical filter, and the second optical filter A second light amount adjustment unit that adjusts the light amount of the measurement target light incident on the first light filter, and a light amount of the first wavelength light extracted by the first light filter, and outputs a detection signal corresponding to the received light amount. A first photodetector; and a second photodetector that receives the amount of light of the second wavelength extracted by the second optical filter and outputs a detection signal corresponding to the amount of received light. The first light fill, which is adjusted by the single light quantity adjustment unit Amount of light incident on the over is adjusted by the second light quantity adjusting unit, being greater than the amount of light incident on the second optical filter.

In this invention, in order to take out the light of the 2nd wavelength in the 2nd measurement wavelength range longer than the 1st measurement wavelength range and the 1st optical filter for taking out the light of the 1st wavelength in the 1st measurement wavelength range The second light filter is separated, and the light amount of the measurement target light incident on the first light filter and the second light filter is adjusted by the first light amount adjustment unit and the second light amount adjustment unit. That is, the first light amount adjustment unit and the second light amount adjustment unit are configured such that the light amount of the measurement target light incident on the first optical filter is larger than the light amount of the measurement target light incident on the second optical filter. In addition, the amount of light to be measured is adjusted. Then, the light extracted from the first optical filter is received by the first detection unit, and the light extracted from the second optical filter is received by the second detection unit.
Here, the first detection unit and the second detection unit are elements that output a detection signal (electric signal) according to the amount of received light by photoelectric conversion processing, and examples thereof include a photodiode and a photo IC. In such first and second detection units, as shown in FIG. 11, the spectral sensitivity in the short wavelength region is low, and the spectral sensitivity in the long wavelength region is high. On the other hand, in this invention, it injects into the 1st optical filter for taking out the light of the 1st wavelength of the 1st measurement wavelength range which is a short wavelength range by the 1st light quantity adjustment part and the 2nd light quantity adjustment part. The light amount of the measurement target light is set to be larger than the light amount of the measurement target light incident on the second optical filter for extracting light of the second wavelength in the second measurement wavelength range which is a long wavelength range. . Therefore, even when the spectral sensitivity in the short wavelength region at the first detection unit is low, measurement based on a larger amount of light can be performed, and the amount of light of each wavelength in the measurement target light can be measured more accurately. It is possible to perform spectroscopic measurement with high accuracy.

  In the light measurement device according to the aspect of the invention, the first light amount adjustment unit includes a first aperture having a first opening that restricts a light amount of the measurement target light incident on the first light filter, and the second light amount adjustment unit. The portion includes a second aperture having a second opening for reducing the amount of the measurement target light incident on the second optical filter, and the first opening of the first aperture is the first aperture of the second aperture. The opening diameter is preferably larger than that of the second opening.

  In this invention, the first aperture diameter of the first aperture is formed larger than the second aperture diameter of the second aperture. For this reason, the light quantity of the measurement target light which is narrowed by the first aperture and enters the first optical filter is larger than the light quantity of the measurement target light which is narrowed by the second aperture and enters the second optical filter. As a result, even when the spectral sensitivity in the short wavelength region at the first detection unit is low, it is possible to carry out measurement based on a larger amount of light, and more accurately measure the light amount of each wavelength in the measurement target light. It is possible to perform spectroscopic measurement with high accuracy.

  In the light measurement device of the present invention, the first light amount adjustment unit includes a first concave reflecting mirror that reflects and collects the measurement target light toward a first focus point and enters the first light filter. The second light amount adjustment unit includes a second concave reflecting mirror that reflects and collects the measurement target light toward a second focus point and enters the second optical filter, and the first concave reflecting mirror is provided. The first focusing distance from the first focusing point to the first focusing point is preferably shorter than the second focusing distance from the second concave reflecting mirror to the second focusing point.

In this invention, the 1st light quantity adjustment part and the 2nd light quantity adjustment part are provided with the 1st concave-surface reflective mirror and the 2nd concave-surface reflective mirror, respectively. The first concave reflecting mirror is formed with a concave shape so that the first condensing distance is shorter than the second condensing distance of the second concave reflecting mirror.
Here, the distance between the first concave reflecting mirror and the first optical filter, the distance between the second concave reflecting mirror and the second optical filter are the same distance, and the first optical filter and the second optical filter are respectively In the case where the first concave filter and the second concave reflector are disposed at a position about the first condensing distance, more light to be measured is collected on the first optical filter. Accordingly, the measurement target light incident on the first optical filter and the amount of light of the first wavelength received by the first detector are received by the measurement target light incident on the second filter and the second detector. The amount of light of the second wavelength can be increased.
Further, when an aperture for reducing the amount of light to be measured is provided on the light incident side of the first light filter and the second light filter, the first condensing distance of the first concave reflecting mirror is the second of the second concave reflecting mirror. Since it is shorter than the condensing distance, the measurement target light reflected by the first concave reflecting mirror is more incident on the aperture opening than the measurement target light reflected by the second concave reflecting mirror. As a result, the measurement target light incident on the first optical filter and the amount of light of the first wavelength received by the first detector are received by the measurement target light incident on the second filter and the second detector. The amount of light of the second wavelength can be increased.
As described above, even when the spectral sensitivity in the short wavelength region at the first detection unit is low, measurement based on a larger amount of light can be performed, and the light amount of each wavelength in the measurement target light can be measured more accurately. It is possible to perform spectroscopic measurement with high accuracy.

  In the light measurement device according to the aspect of the invention, the first light amount adjustment unit may include a first concave reflecting mirror that reflects and collects the measurement target light incident on the first reflection region and causes the measurement target light to enter the first light filter. The second light amount adjustment unit includes a second concave reflecting mirror that reflects and collects the measurement target light incident on the second reflection region and enters the second light filter, and the first concave surface The first reflecting area of the reflecting mirror is preferably larger than the second reflecting area of the second concave reflecting mirror.

  In this invention, since the first reflection area of the first concave reflecting mirror is larger than the second reflection area of the second concave reflecting mirror, more measurement target light is reflected by the first concave reflecting mirror than the second concave reflecting mirror. And incident on the first optical filter. Accordingly, the measurement target light incident on the first optical filter and the amount of light of the first wavelength received by the first detector are received by the measurement target light incident on the second filter and the second detector. The amount of light of the second wavelength can be increased. As a result, even when the spectral sensitivity in the short wavelength region at the first detection unit is low, it is possible to carry out measurement based on a larger amount of light, and more accurately measure the light amount of each wavelength in the measurement target light. It is possible to perform spectroscopic measurement with high accuracy.

  In the light measurement device according to the aspect of the invention, the first light amount adjustment unit includes a plurality of first concave reflecting mirrors that reflect and collect the measurement target light and enter the first light filter, and the second light amount. The adjustment unit includes at least one second concave reflecting mirror that reflects and collects the measurement target light and enters the second optical filter, and the first concave reflecting mirror of the first light amount adjusting unit. Is preferably larger than the number of the second concave reflecting mirrors of the second light quantity adjustment unit.

  In the present invention, the number of the first concave reflecting mirrors that reflect the measurement target light toward the first optical filter is greater than the number of the second concave reflective mirrors that reflect the measurement target light toward the second optical filter. For this reason, more light can be made incident on the first optical filter by these first concave reflecting mirrors. Accordingly, the measurement target light incident on the first optical filter and the amount of light of the first wavelength received by the first detector are received by the measurement target light incident on the second filter and the second detector. The amount of light of the second wavelength can be increased. As a result, even when the spectral sensitivity in the short wavelength region at the first detection unit is low, it is possible to carry out measurement based on a larger amount of light, and more accurately measure the light amount of each wavelength in the measurement target light. It is possible to perform spectroscopic measurement with high accuracy.

  In the light measurement device of the present invention, the first light amount adjustment unit includes a first condenser lens that condenses the measurement target light toward a first lens focus point and enters the first light filter, The second light quantity adjustment unit includes a second condenser lens that condenses the measurement target light toward a second lens focus point and makes the measurement target light incident on the second optical filter, The first lens focusing distance to the lens focusing point is preferably shorter than the second lens focusing distance from the second focusing lens to the second lens focusing point.

In this invention, the 1st light quantity adjustment part and the 2nd light quantity adjustment part are provided with the 1st condensing lens and the 2nd condensing lens, respectively. The first condensing lens is formed with a lens curvature such that the first lens condensing distance is shorter than the second lens condensing distance of the second condensing lens.
Here, the distance between the first condenser lens and the first optical filter, the distance between the second condenser lens and the second optical filter are the same distance, and the first optical filter and the second optical filter are respectively In the case where the first condensing lens and the second condensing lens are arranged at a position about the first lens condensing distance, a large amount of measurement target light is condensed by the first optical filter. Accordingly, the measurement target light incident on the first optical filter and the amount of light of the first wavelength received by the first detector are received by the measurement target light incident on the second filter and the second detector. The amount of light of the second wavelength can be increased.
Further, when an aperture for reducing the amount of light to be measured is provided on the light incident side of the first light filter and the second light filter, the first lens condensing distance of the first condensing lens is the second condensing distance of the second condensing lens. Because it is shorter than the lens focusing distance, the measurement target light collected by the first condenser lens is more incident on the aperture opening than the measurement target light collected by the second condenser lens. The As a result, the measurement target light incident on the first optical filter and the amount of light of the first wavelength received by the first detector are received by the measurement target light incident on the second filter and the second detector. The amount of light of the second wavelength can be increased.
As described above, even when the spectral sensitivity in the short wavelength region at the first detection unit is low, measurement based on a larger amount of light can be performed, and the light amount of each wavelength in the measurement target light can be measured more accurately. It is possible to perform spectroscopic measurement with high accuracy.

  In the light measurement device of the present invention, the first light amount adjustment unit includes a first condenser lens that collects the measurement target light incident within the first lens diameter and causes the measurement target light to enter the first light filter, The second light amount adjustment unit includes a second condenser lens that condenses the measurement target light incident within a second lens diameter and enters the second light filter, and the second condenser unit includes the second condenser lens. The first lens diameter is preferably larger than the second lens diameter of the second condenser lens.

  In this invention, since the first lens diameter of the first condenser lens is larger than the second lens diameter of the second condenser lens, more measurement target light enters the first condenser lens than the second condenser lens. Then, the light is collected and incident on the first optical filter. Accordingly, the measurement target light incident on the first optical filter and the amount of light of the first wavelength received by the first detector are received by the measurement target light incident on the second filter and the second detector. The amount of light of the second wavelength can be increased. As a result, even when the spectral sensitivity in the short wavelength region at the first detection unit is low, it is possible to carry out measurement based on a larger amount of light, and more accurately measure the light amount of each wavelength in the measurement target light. It is possible to perform spectroscopic measurement with high accuracy.

  In the light measurement device of the present invention, the light measurement device includes a light source that irradiates light to the measurement target, and the first light amount adjustment unit and the second adjustment unit are emitted from the light source and reflected by the measurement target light. It is preferable to adjust the amount of light.

  In the present invention, for example, in chromaticity measurement, a light source such as an incandescent light bulb used as a reference light source is used to irradiate the measurement target with light, and the amount of measurement target light reflected by the measurement target is determined by the first detection unit and Measure with the second detector. Such a light source generally has a small radiation energy of light in a short wavelength region and a large radiation energy of light in a long wavelength region. Therefore, for example, when the desired wavelength light is extracted by one optical filter and the light quantity of the wavelength light is detected by one detector, the detection accuracy of the wavelength light on the short wavelength side is lowered. Also in the detector, as described above, the spectral sensitivity in the short wavelength region is smaller than the spectral sensitivity in the long wavelength region, so that the detection accuracy may be further reduced. However, in the present invention, as described above, even when such a light source is used, the first and second light amount adjustment units change the light amount of the measurement target light incident on the first optical filter. Since it can be made larger than the amount of measurement target light incident on the two-light filter, it is possible to suppress a decrease in detection accuracy due to the difference in the radiant energy of the light source, and to detect the amount of light with higher accuracy. Can do.

  In the light measurement device of the present invention, the first optical filter and the second optical filter include a first substrate, a second substrate facing the first substrate, and a first reflective film provided on the first substrate. A second reflective film that is provided on the second substrate and faces the first reflective film, and an electrostatic actuator that varies a gap between the first reflective film and the second reflective film. Is preferred.

  According to this invention, the first optical filter and the second optical filter include a first substrate and a second substrate that are arranged to face each other, and a first reflective film and a second reflective film that are disposed between these substrates. And an electrostatic actuator that adjusts a gap interval between the first reflective film and the second reflective film. The first and second optical filters having such a configuration function as a so-called Fabry-Perot etalon, and only the light whose integer multiple of a half wavelength matches the gap interval between the first reflective film and the second reflective film is intensified. To pass through the reflective film. Therefore, the first wavelength and the second wavelength can be easily switched by controlling the electrostatic actuator to switch the gap interval between the first reflective film and the second reflective film. Thereby, the light of the desired first wavelength in the first wavelength range can be extracted by the first optical filter, and the light of the desired second wavelength in the second wavelength range can be extracted by the second optical filter. .

In the light measurement device according to the aspect of the invention, it is preferable that the measurement target light is visible light, and the first measurement wavelength region and the second measurement wavelength region include a visible light region.
In the present invention, the chromaticity of the measurement target light can be measured by setting the wavelength range of the measurement target within the visible light range.

It is a figure which shows schematic structure of the spectrometer of 1st embodiment which concerns on this invention. It is a top view which shows schematic structure of the etalon in this embodiment. FIG. 3 is a cross-sectional view of the etalon taken along line III-III in FIG. It is a figure which shows the spectral characteristic of an etalon. In the spectrometer of 1st embodiment, it is a figure which shows the light reception amount calculated | required by the detection signal of each photodetector. FIG. 5 is a comparative example with respect to FIG. 5, and shows a received light amount obtained from a detection signal of a photodetector when the measurement target light is dispersed by one etalon and light separated by one photodetector is received. It is. It is a figure which shows schematic structure of the spectrometer of 2nd embodiment which concerns on this invention. It is a figure which shows the radiant energy of the light of each wavelength in the white light inject | emitted from an incandescent lamp. It is a figure which shows schematic structure of the spectrometer of 3rd embodiment which concerns on this invention. It is a figure which shows schematic structure of the spectrometer of 4th embodiment which concerns on this invention. It is a figure which shows the spectral sensitivity characteristic of a general silicon photodiode.

Hereinafter, a spectroscopic measurement device (light measurement device) according to a first embodiment of the present invention will be described with reference to the drawings.
[1. Overall configuration of spectroscopic measurement device]
FIG. 1 is a diagram showing a schematic configuration of a spectroscopic measurement apparatus as a light measurement apparatus according to the first embodiment of the present invention.
The spectroscopic measurement device 1 is a device that measures the amount of light at each wavelength of the measurement target light reflected by the inspection target A. Specifically, as shown in FIG. 1, the spectroscopic measurement apparatus 1 includes a short wavelength region measuring unit 10A, a long wavelength region measuring unit 10B, and a measurement control unit (not shown). The short wavelength region measuring unit 10A includes a short wavelength region etalon 2A that is the first optical filter of the present invention, a short wavelength region photodetector 3A that is the first photodetector, and the first of the present invention. And a short wavelength range aperture 4 </ b> A constituting the light amount adjusting unit and the first aperture. The long wavelength band measuring unit 10B includes a long wavelength band etalon 2B that is the second optical filter of the present invention, a long wavelength band photodetector 3B that is the second photodetector, A long wavelength range aperture 4 </ b> B constituting the light amount adjustment unit and the second aperture.

[1-1. Composition of etalon
The short wavelength region etalon 2A of the short wavelength region measurement unit 10A and the long wavelength region etalon 2B of the long wavelength region measurement unit 10B are etalons 2 having substantially the same configuration.
FIG. 2 is a plan view showing a schematic configuration of the etalon 2 in the present embodiment. 3 is a cross-sectional view taken along line III-III in FIG.

  As shown in FIGS. 2 and 3, the etalon 2 (2A, 2B) is, for example, a planar square plate-like optical member, and one side is formed to be 10 mm, for example. The etalon 2 includes a first substrate 21 and a second substrate 22. These two substrates 21 and 22 are made of, for example, various glasses such as soda glass, crystalline glass, quartz glass, lead glass, potassium glass, borosilicate glass, and alkali-free glass, or crystal. . Among these, as a constituent material of each board | substrate 21 and 22, glass containing alkali metals, such as sodium (Na) and potassium (K), for example is preferable, and each board | substrate 21 and 22 is formed with such glass. Thus, it becomes possible to improve the reflection films 23 and 24, which will be described later, the adhesion between the electrodes, and the bonding strength between the substrates. These two substrates 21 and 22 are joined together by joining methods 213 and 223 formed in the vicinity of the outer peripheral portion by a joining method such as room temperature activation joining or adhesive joining using an adhesive layer. It is configured.

A first reflective film 23 and a second reflective film 24 are provided between the first substrate 21 and the second substrate 22. Here, the first reflective film 23 is fixed to the surface of the first substrate 21 facing the second substrate 22, and the second reflective film 24 is fixed to the surface of the second substrate 22 facing the first substrate 21. ing. Further, the first reflective film 23 and the second reflective film 24 are arranged to face each other with a gap G interposed therebetween.
Further, an electrostatic actuator 25 for adjusting the size of the gap G between the first reflective film 23 and the second reflective film 24 is provided between the first substrate 21 and the second substrate 22.

(1-1-1. Configuration of the first substrate)
The first substrate 21 is formed by processing a glass substrate having a thickness of, for example, 500 μm by etching. Specifically, as shown in FIGS. 2 and 3, an electrode forming groove 211 and a reflective film fixing portion 212 are formed on the first substrate 21 by etching.
The electrode formation groove 211 is formed in a circular shape centered on the plane center point in a plan view (hereinafter referred to as etalon plan view) of the etalon 2 as shown in FIG. The reflection film fixing portion 212 is formed so as to protrude from the center portion of the electrode forming groove 211 toward the second substrate 22 in the plan view.

The electrode forming groove 211 includes an electrode fixing surface 211A (see FIG. 3) formed in a ring shape between the outer peripheral edge of the reflective film fixing portion 212 and the inner peripheral wall surface of the electrode forming groove 211. A ring-shaped first electrode 251 (see FIG. 3) is formed on the electrode fixing surface 211A.
In addition, a concave groove (not shown) is formed in the first substrate 21 from the electrode forming groove 211 toward the apex direction of the first substrate 21. Further, in the plan view of the etalon shown in FIG. 2, the first extraction electrode 251A extends from the first electrode 251 formed on the electrode fixing surface 211A in the upper left direction and the lower right direction in the drawing along the concave groove. ing. These first extraction electrodes 251A are each formed with a first electrode pad 251B at the tip, and these first electrode pads 251B are connected to the measurement control unit.

As described above, the reflection film fixing portion 212 is formed in a columnar shape coaxial with the electrode forming groove 211 and having a smaller diameter than the electrode forming groove 211. In the present embodiment, as shown in FIG. 3, the reflection film fixing surface 212A facing the second substrate 22 of the reflection film fixing portion 212 is formed closer to the second substrate 22 than the electrode fixing surface 211A. However, the present invention is not limited to this. The height positions of the electrode fixing surface 211A and the reflecting film fixing surface 212A are the gap G between the first reflecting film 23 fixed to the reflecting film fixing surface 212A and the second reflecting film 24 formed on the second substrate 22. , The dimension between the first electrode 251 and the second electrode 252 described later formed on the second substrate 22, and the thickness dimension of the first reflective film 23 and the second reflective film 24 are set as appropriate. The configuration is not limited to the above. For example, when a dielectric multilayer film reflective film is used as the reflective films 23 and 24, when the thickness dimension increases, the electrode fixing surface 211A and the reflective film fixing surface 212A are formed on the same surface, The reflection film fixing groove on the cylindrical concave groove may be formed at the center of the fixing surface 211A, and the reflection film fixing surface 212A may be formed on the bottom surface of the reflection film fixing groove.
However, the electrostatic attractive force acting between the first electrode 251 and the second electrode 252 is inversely proportional to the square of the distance between the first electrode 251 and the second electrode 252. Accordingly, the closer the distance between the first electrode 251 and the second electrode 252 is, the larger the variation amount of the gap G with respect to the voltage value of the electrostatic attractive force. In particular, when the variable dimension of the gap G is very small, variable control of the gap G becomes difficult. Therefore, as described above, even when the reflective film fixing groove is formed, it is preferable to secure the depth dimension of the electrode forming groove 211 to some extent. In the present embodiment, for example, it is formed to 1 μm. preferable.

  Further, it is preferable that the reflection film fixing surface 212A of the reflection film fixing portion 212 is designed to have a groove depth in consideration of a wavelength range that allows the etalon 2 to pass therethrough. For example, in the present embodiment, in the short wavelength region etalon 2A, light in the first measurement wavelength region of 350 nm to 500 nm is extracted, and therefore the gap G between the first reflective film 23 and the second reflective film 24 is at least 175 nm. The groove depth is set to be adjustable in the range of ˜250 nm. In the long wavelength region etalon 2B, in order to extract light in the second measurement wavelength region of 500 nm to 750 nm, the gap G between the first reflective film 23 and the second reflective film 24 is at least in the range of 250 nm to 350 nm. The groove depth can be adjusted with.

The first reflective film 23 formed in a circular shape with a diameter of, for example, about 3 mm is fixed to the reflective film fixing surface 212A. The first reflective film 23 may be formed of a metal single layer film or a dielectric multilayer film.
Here, when a metal single layer film such as an AgC layer is used, it is possible to cover the entire visible light region as a wavelength region that can be dispersed by one etalon 2, but the transmittance and resolution are lowered. On the other hand, when a dielectric multilayer film is used, the wavelength range that can be dispersed by one etalon 2 is narrowed, but the transmittance of the dispersed light is large and the resolution is also increased.
By the way, in this embodiment, the etalon 2A for short wavelength region for dispersing light in the range of the first measurement wavelength region and the etalon for long wavelength region for dispersing light in the range of the second measurement wavelength region. Therefore, it is not necessary to cover a wide wavelength range with one etalon 2. For the above reasons, in the present embodiment, it is preferable to use a dielectric multilayer film having higher transmittance and good resolution as the first reflective film 23.

  Further, the first substrate 21 is provided with an antireflection film (AR) (not shown) at a position corresponding to the first reflection film 23 on the lower surface opposite to the upper surface facing the second substrate 22. This antireflection film is formed by alternately laminating low refractive index films and high refractive index films, and reduces the reflectance of visible light on the surface of the first substrate 21 and increases the transmittance.

(1-1-2. Configuration of Second Substrate)
The second substrate 22 is formed by processing a glass substrate having a thickness of, for example, 200 μm by etching.
Specifically, in the plan view as shown in FIG. 2, the second substrate 22 has a circular movable portion 221 centered on the substrate center point and a connection that is coaxial with the movable portion 221 and holds the movable portion 221. Holding part 222.

The movable part 221 is formed to have a thickness dimension larger than that of the connection holding part 222. For example, in this embodiment, the movable part 221 is formed to be 200 μm, which is the same dimension as the thickness dimension of the second substrate 22. The movable portion 221 includes a movable surface 221A parallel to the reflective film fixing portion 212, and the second reflective film 24 facing the first reflective film 23 with a gap G fixed to the movable surface 221A. .
Here, the second reflective film 24 is preferably formed of a reflective film having the same configuration as the first reflective film 23 described above, that is, a dielectric multilayer film.

  Further, the movable portion 221 is provided with an antireflection film (AR) (not shown) at a position corresponding to the second reflective film 24 on the upper surface opposite to the movable surface 221A. This antireflection film has the same configuration as the antireflection film formed on the first substrate 21, and is formed by alternately laminating a low refractive index film and a high refractive index film.

The connection holding part 222 is a diaphragm surrounding the periphery of the movable part 221 and has a thickness dimension of, for example, 50 μm. A ring-shaped second electrode 252 that faces the first electrode 251 with an electromagnetic gap of about 1 μm is formed on the surface of the connection holding portion 222 that faces the first substrate 21. Here, the electrostatic actuator 25 is configured by the second electrode 252 and the first electrode 251 described above.
In addition, a pair of second extraction electrodes 252A are formed from the part of the outer peripheral edge of the second electrode 252 toward the outer peripheral direction. Specifically, in the etalon plan view shown in FIG. 2, the second extraction electrode 252 </ b> A is formed to extend toward the upper right direction and the lower left direction of the etalon 2. These second extraction electrodes 252A are each formed with a second electrode pad 252B at the tip, and these second electrode pads 252B are connected to the measurement control unit.

Next, the operation of the etalon 2 as described above will be described. FIG. 4 is a diagram showing spectral characteristics of the short wavelength region etalon 2A and the long wavelength region etalon 2B.
In the etalon 2 as described above, for example, when measurement target light is incident from the second substrate 22 side, the measurement target light is subjected to multiple interference between the first reflective film 23 and the second reflective film 24. Of the light to be measured, light whose integer multiple of ½ of the wavelength matches the size of the gap G between the first reflective film 23 and the second reflective film 24 is intensified by multiple interference, and the first substrate 21 Permeate to the side. At this time, when a driving voltage is applied from the measurement control unit to the first electrode 251 and the second electrode 252 of the electrostatic actuator 25, an electrostatic attractive force acts between the first electrode 251 and the second electrode 252, and the second The movable portion 221 of the substrate 22 is displaced toward the first substrate 21 side. Thereby, the dimension of the gap G between the first reflective film 23 and the second reflective film 24 is changed, and the wavelength of the light transmitted to the first substrate 21 side is changed as shown in FIG.
Specifically, as shown in FIG. 4, in the short wavelength region etalon 2A, the first wavelength corresponding to the dimension of the gap G in the range of the first measurement wavelength region (350 to 500 nm) of the measurement target light. Only light (first wavelength light) is transmitted. In the etalon for long wavelength region 2B, only the light of the second wavelength (second wavelength light) corresponding to the dimension of the gap G is transmitted in the range of the second measurement wavelength region (500 to 750 nm) of the measurement target light. .

[1-2. Photodetector configuration)
The short wavelength region photodetector 3A and the long wavelength region photodetector 3B are the photodetectors 3 having the same configuration. These photodetectors 3 (3A, 3B) are provided with a plurality of photoelectric conversion elements such as photodiodes and photo ICs, for example, and when receiving light, output a detection signal corresponding to the amount of received light. Specifically, the short wavelength region photodetector 3A receives the first wavelength light transmitted through the short wavelength region etalon 2A, and a detection signal (short wavelength side detection signal) corresponding to the light amount of the first wavelength light. Is output to the measurement control unit. The long wavelength region photodetector 3B receives the second wavelength light transmitted through the long wavelength region etalon 2B, and a detection signal (long wavelength side detection signal) corresponding to the amount of the second wavelength light is measured and controlled. To the output.

Further, the photodetector 3 (3A, 3B) using such a photoelectric conversion element (for example, a silicon photodiode) has spectral sensitivity characteristics as shown in FIG. 11 described above. That is, the light detector 3 has a high spectral sensitivity and can detect the light amount with high accuracy with light having a long wavelength, but the spectral sensitivity decreases as it goes toward the short wavelength side. Decreases.
With respect to such a problem, in the present invention, the light to be measured is incident on the short wavelength region etalon 2A that transmits the first wavelength light from the range of the first measurement wavelength region on the short wavelength region side. A first light amount adjustment unit that adjusts the light amount of the measurement target light, and a long wavelength region etalon 2B that transmits the second wavelength light from the range of the second measurement wavelength region on the long wavelength region side of the measurement target light. On the other hand, by providing a second light amount adjustment unit that adjusts the light amount of the measurement target light incident thereon, the above-described decrease in the light amount detection accuracy is suppressed. In the first embodiment, as an example of the first light amount adjustment unit and the second light amount adjustment unit, the measurement target light is narrowed by the aperture 4 and the light amount of the measurement target light incident on the etalon 2 is limited. Show.

[1-3. Aperture configuration)
The short wavelength range aperture 4A and the long wavelength range aperture 4B are respectively provided on the incident side of the measurement target light of the short wavelength range etalon 2A and the long wavelength range etalon 2B, that is, on the second substrate 22 side. ing. The short wavelength aperture 4A and the long wavelength aperture 4B include a first opening 41 and a second opening 42, respectively, as shown in FIG. The short wavelength range aperture 4A and the long wavelength range aperture 4B are incident on the short wavelength range etalon 2A and the long wavelength range etalon 2B through the first opening 41 and the second opening 42, respectively. The amount of light to be measured is limited by reducing the optical path diameter of the target light.

In the present embodiment, the diameter (Da) of the first opening 41 of the short wavelength region aperture 4A is formed larger than the diameter (Db) of the second opening 42 of the long wavelength region aperture 4B. Therefore, the amount of the measurement target light that is focused by the short wavelength range aperture 4A and incident on the short wavelength range etalon 2A is reduced by the long wavelength range aperture 4B and is measured by the long wavelength range etalon 2B. More than the amount of light.
The opening diameters Da and Db of the first opening 41 and the second opening 42 are the measurement wavelength regions of the measurement target light detected by the short wavelength region photodetector 3A and the long wavelength region photodetector 3B. Is set as appropriate. For example, in the present embodiment, in the short wavelength region etalon 2A, a predetermined first wavelength light is extracted from the first measurement wavelength region of 350 nm to 500 nm in the visible light region, and the short wavelength region photodetector 3A performs the first operation. Receives wavelength light. Further, in the long wavelength region etalon 2B, a predetermined second wavelength light is extracted from the second measurement wavelength region of 500 nm to 750 nm in the visible light region, and the long wavelength region photodetector 3B receives the second wavelength light. . In this case, as the measurement target light, white light having the same amount of light of all wavelengths is used, and the first wavelength light (500 nm) having the maximum wavelength in the first measurement wavelength range is taken out by the short wavelength etalon 2A. When the second wavelength light (750 nm) having the maximum wavelength in the second measurement wavelength range is extracted by the long wavelength range etalon 2B, the magnitude of the short wavelength side detection signal output from the short wavelength range photodetector 3A The opening diameters Da and Db of the first opening 41 and the second opening 42 are adjusted so that the magnitudes of the long-wavelength side detection signals output from the long-wavelength photodetector 3B are substantially the same. ing.

[1-4. Configuration of measurement control unit)
As described above, the measurement control unit is connected to the first electrode pad 251B and the second electrode pad 252B of the etalon 2 (2A, 2B). Then, the measurement control unit changes the size of the gap G of the etalon 2 by applying a driving voltage to the first electrode 251 and the second electrode 252 via the first electrode pad 251B and the second electrode pad. Then, the wavelengths of the first wavelength light and the second wavelength light transmitted through the etalon 2 are switched.
The measurement control unit is connected to the photodetectors 3 (3A, 3B) and receives detection signals output from these photodetectors 3. And a measurement control part calculates the light reception amount with respect to each wavelength based on these input detection signals, and implements the measurement process of the spectral characteristic of measurement object light.

[2. Spectral sensitivity of spectrometer
Next, the spectral sensitivity in the above-described spectrometer will be described. FIG. 5 is a diagram showing the amount of received light obtained from the detection signal of each photodetector in the spectroscopic measurement apparatus of the present embodiment. FIG. 6 is a comparative example with respect to FIG. 5, and the light received by the detection signal of the photodetector when the light to be measured is dispersed by one etalon and the light separated by one photodetector is received. It is a figure which shows quantity. 5 and 6 show the amount of light received when white light having substantially the same amount of light of each wavelength is used as measurement target light.
As shown in FIG. 6, when the measurement target light is spectrally separated by one etalon and the spectrally separated light is received by the photodetector, the spectral sensitivity of the photodetector has characteristics as shown in FIG. 11. Also in the spectroscopic measurement apparatus, the amount of light received with respect to light on the long wavelength side is large, and the amount of light received with respect to light on the short wavelength side is small. On the other hand, in the present embodiment, the amount of measurement target light incident on the short wavelength region etalon 2A increases, and accordingly, the amount of received light within the first measurement wavelength region of the short wavelength region also increases. As shown in FIG. 5, the light amount of the first wavelength light detected by the short wavelength region photodetector 3A also increases. Therefore, in the spectroscopic measurement apparatus of this embodiment, the measurement accuracy in the short wavelength region is improved as compared with the case where the spectral characteristics of the light to be measured is measured with one etalon and one detector as shown in FIG. As a whole, the measurement accuracy of spectral characteristics can be improved.

[3. Effect of First Embodiment)
As described above, in the spectrometer 1 of the first embodiment, the short wavelength region etalon 2A that extracts the first wavelength light from the light within the first measurement wavelength region on the short wavelength side of the measurement target light. Among the measurement target light, the long wavelength etalon 2B for extracting the second wavelength light from the light within the second measurement wavelength range on the long wavelength side, and the first wavelength light are received and a detection signal is output. A short wavelength region photodetector 3A and a long wavelength region photodetector 3B that receives the second wavelength light and outputs a detection signal are provided. A short wavelength region aperture 4A is provided on the light incident side of the short wavelength region etalon 2A, and a long wavelength region aperture 4B is disposed on the light incident side of the long wavelength region etalon 2B. The first opening 41 of the aperture 4A for the region has a larger opening diameter than the second opening 42 of the aperture 4B for the long wavelength region.
For this reason, the light amount of the measurement target light incident on the short wavelength region etalon 2A is larger than the light amount of the measurement target light incident on the long wavelength region etalon 2B. For this reason, the light quantity of 1st wavelength light increases, and in connection with this, the light reception amount of 1st wavelength light also increases in 3 A of photodetectors for short wavelength regions. Therefore, the measurement accuracy of the spectral characteristics of the spectrometer 1 can be improved.

  In addition, the first and second optical filters of the present invention include a first substrate 21 and a second substrate 22 arranged to face each other, a first reflective film 23 provided between the first substrate 21 and the second substrate 22, and The etalon 2 (2A, 2B) includes a second reflective film 24 and an electrostatic actuator 25 that adjusts the size of the gap G between the first reflective film 23 and the second reflective film 24. In such an etalon 2, by controlling the voltage applied to the electrostatic actuator 25, the gap dimension of the gap G can be adjusted by electrostatic attraction, and light corresponding to the gap dimension of the gap G is emitted. It can be taken out. Therefore, in the etalon 2A for the short wavelength region, the first wavelength can be switched and transmitted within the first measurement wavelength region, and in the etalon 2B for the long wavelength region, the second wavelength can be switched within the second measurement wavelength region. It can be transmitted. For this reason, in the spectroscopic measurement apparatus 1, the light quantity with respect to each wavelength range can be measured, for example with respect to the visible light whole region, and a highly accurate spectral characteristic measurement can be implemented.

  Further, compared to the case where light of one wavelength is extracted from the measurement target light by one etalon 2, light of different wavelengths can be extracted by the two etalons 2A and 2B. It can be shortened.

  In addition, since the first measurement wavelength range is set to 350 to 500 nm and the second measurement wavelength range is set to 500 to 750 nm, it is possible to cover almost the entire visible light, and the accurate color of the measurement target light. Characteristics etc. can also be implemented.

[Second Embodiment]
Next, a spectroscopic measurement apparatus according to a second embodiment of the present invention will be described with reference to the drawings.
FIG. 7 is a diagram showing a schematic configuration of the spectrometer according to the second embodiment. In the following description of the embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.
In the spectroscopic measurement device 1 of the first embodiment, the measurement target light, which is parallel light reflected by the measurement target A, is focused by the aperture 4 (4A, 4B), and is incident on the short wavelength etalon 2A. The light quantity of the measurement target light is made larger than the light quantity of the measurement target light incident on the long wavelength region etalon 2B, thereby improving the measurement accuracy.
In contrast, in the spectroscopic measurement apparatus 1A of the second embodiment, the measurement target light is further condensed using a concave reflecting mirror and incident on the short wavelength region etalon 2A and the long wavelength region etalon 2B. Adjust the amount of measurement target light.
In the first embodiment, the natural light reflected by the measurement target A is the measurement target light. However, in the second embodiment, white light is emitted from the light source 5 and, for example, the white light is converted into parallel light by the lens 6. Then, the light is reflected by the measurement object A, and the reflected light is used as the measurement object light.

  Specifically, as shown in FIG. 7, the spectroscopic measurement device 1 </ b> A includes a light source 5, a short wavelength region measurement unit 10 </ b> A, a long wavelength region measurement unit 10 </ b> B, and a first light amount adjustment unit of the present invention. A short-wavelength concave reflecting mirror 7A that is a first concave reflecting mirror, and a long-wavelength concave reflecting mirror 7B that is a second concave reflecting mirror that constitutes the second light quantity adjusting unit of the present invention.

  The light source 5 is a device that emits light to the measurement target A. As the light source 5, any device may be used as long as it can emit light, such as an incandescent light bulb or an LED. In particular, when measuring the chromaticity of the measurement target A from the spectroscopic measurement device 1 </ b> A. It is preferable to use an incandescent lamp that is a CIE standard light source defined by the CIE (International Commission on Illumination).

Here, FIG. 8 shows general spectral characteristics of the incandescent lamp.
When measuring chromaticity based on the CIE color system, it is preferable to use an incandescent lamp as the light source 5 as described above. However, this incandescent lamp has spectral characteristics as shown in FIG. Yes. That is, the white light emitted from the incandescent bulb has a larger radiant energy of light in the long wavelength region than that of light in the short wavelength region. Further, as described above, also in each photodetector 3, the spectral sensitivity in the short wavelength region is lower than the spectral sensitivity in the long wavelength region. Therefore, when such an incandescent bulb is used as the light source 5, the amount of measurement target light incident on the short wavelength etalon 2A is further increased as compared with the case where natural light is used as in the first embodiment. Need arises.
Therefore, in the second embodiment, the light quantity of the measurement target light is increased by condensing the measurement target light using the concave reflecting mirror 7.

Specifically, these concave reflecting mirrors 7 (7A, 7B) are respectively provided facing the measurement unit 10 (10A, 10B), and the measurement target light reflected by the measurement target A is measured by the measurement unit. 10 (10A, 10B) is provided. Here, the short wavelength band concave reflecting mirror 7A, which is the first concave reflecting mirror facing the short wavelength band measuring section 10A, and the second concave reflecting mirror, facing the long wavelength band measuring section 10B, are long. The area and concave curvature of the reflection region 71 that is a region capable of reflecting the measurement target light are different from those of the concave reflection mirror for wavelength region 7B.
That is, as shown in FIG. 7, the area Sa of the first reflecting region 71A of the concave reflecting mirror for short wavelength region 7A is formed larger than the area Sb of the second reflecting region 71B of the concave reflecting mirror for long wavelength region 7B. ing. Thereby, in the concave reflecting mirror for short wavelength region 7A, it becomes possible to make more measurement target light incident on the measuring unit for short wavelength region 10A than in the concave reflecting mirror for long wavelength region 7B. The amount of the first wavelength light received by the device 3A also increases.

Moreover, the concave reflection mirror for short wavelength region 7A and the concave reflection mirror for long wavelength region 7B have different curvatures in the reflection region 71, whereby the distance from the reflection region 71 to the focus point where the measurement target light is collected. (Condensing distance) is different. Specifically, the distance (first collection) from the center point of the first reflecting region 71A of the concave reflecting mirror for short wavelength region 7A to the focus point (first focus point F1) of the concave reflecting mirror for short wavelength region 7A. The optical distance La1) is a condensing distance from the center point of the second reflection region 71B of the long-wavelength concave reflector 7B to the focus point (second focus point F2) of the long-wavelength concave reflector 7B. It is set shorter than the second condensing distance Lb1).
For this reason, among the measurement target light reflected by the short wavelength concave mirror 7A, the measurement target light emitted through the first opening 41 of the short wavelength aperture 4A and emitted to the short wavelength etalon 2A side. Of the measurement target light reflected by the long-wavelength concave reflecting mirror 7B passes through the second opening 42 of the long-wavelength aperture 4B and is emitted toward the long-wavelength etalon 2B. The amount of light to be measured is greater than the amount of light to be measured.

  Similarly to the first embodiment, the opening diameter of the first opening 41 of the short wavelength aperture 4A is larger than the opening diameter of the second opening of the long wavelength aperture 4B. The light quantity of the measurement target light incident on the wavelength range etalon 2A side is larger than the light quantity of the measurement target light incident on the long wavelength range etalon 2B side.

  As described above, the light amount of the measurement target light incident on the short wavelength region measurement unit 10A is larger than the light amount of the measurement target light incident on the long wavelength region measurement unit 10B. In addition to the light amount adjustment by the aperture diameter of the aperture 4, the light amount adjustment is performed by the difference in the area of the reflection region 71 of the concave reflecting mirror 7 and the condensing distance, so that the spectroscopic measurement apparatus 1 of the first embodiment can be used. It is possible to effectively increase the amount of measurement target light incident on the short wavelength region measurement unit 10A.

  In addition, as the areas Sa and Sb and the condensing distances La1 and Lb1 of the reflection region 71 of the concave reflecting mirror 7, the measurement light for the short wavelength region 10A and the long measurement light are used as in the first embodiment. It sets so that the measurement result of the measuring object light which is white light correctly will be obtained in the state which entered into the measurement part 10B for wavelength regions. That is, the measurement target light is white light, the first wavelength light (500 nm) of the maximum wavelength in the first measurement wavelength range is taken out by the short wavelength range etalon 2A, and the long wavelength range etalon 2B is taken in the second measurement wavelength range. When the second wavelength light (750 nm) of the maximum wavelength is extracted, the magnitude of the short wavelength side detection signal output from the short wavelength region photodetector 3A and the long wavelength region photodetector 3B are output. The areas Sa and Sb of the reflecting region 71 of the concave reflecting mirror 7 and the condensing distances La1 and Lb1 are adjusted so that the magnitudes of the long wavelength side detection signals are substantially the same.

[Effects of Second Embodiment]
As described above, in the spectroscopic measurement apparatus 1A of the second embodiment, the short wavelength region concave reflecting mirror 7A and the long wavelength region concave surface are opposed to the short wavelength region measurement unit 10A and the long wavelength region measurement unit 10B. A reflecting mirror 7B is provided. In these concave reflecting mirrors 7, the first condensing distance La1 of the concave reflecting mirror for short wavelength region 7A is set shorter than the second condensing distance Lb1 of the concave reflecting mirror for long wavelength region 7B.
For this reason, the light quantity of the measurement target light reflected by the concave reflecting mirror 7A for the short wavelength region and passing through the first opening 41 of the aperture 4A for the short wavelength region is reflected by the concave reflecting mirror 7B for the long wavelength region and is long. The amount of light to be measured passes through the second opening 42 of the wavelength band aperture 4B. Therefore, the amount of light of the measurement target light in the short wavelength range measured by the short wavelength range measurement unit 10A increases, and the amount of the first wavelength light extracted by the short wavelength range etalon 2A also increases. Thereby, in the photodetector 3, even if the spectral sensitivity on the short wavelength region side is low, the measurement can be performed with a large amount of light, so that the measurement accuracy can be improved.

In the spectroscopic measurement apparatus 1A, in the concave reflecting mirror 7, the area Sa of the first reflecting region 71A of the concave reflecting mirror 7A for short wavelength region is the area Sb of the second reflecting region 71B of the concave reflecting mirror 7B for long wavelength region. Is set larger than.
For this reason, in the concave reflecting mirror for short wavelength region 7A, more measurement target light can be reflected to the measuring unit for short wavelength region 10A than the concave reflecting mirror for long wavelength region 7B. Thereby, in the photodetector 3, even if the spectral sensitivity on the short wavelength region side is low, the measurement can be performed with a large amount of light, so that the measurement accuracy can be improved.

In the spectroscopic measurement apparatus 1A of the second embodiment, light from the light source 5 that is an incandescent bulb is used as measurement target light reflected by the measurement target A. By using the CIE standard light source defined by such CIE (International Commission on Illumination), the measurement control unit is an international standard when analyzing the chromaticity of the measuring object A based on the light quantity of each wavelength light. The measurement result can be used as it is as the chromaticity that matches the CIE color system without correcting to the chromaticity that matches the CIE color system. For this reason, chromaticity measurement can be implemented efficiently.
Further, in such a light source 5, the radiation energy of light on the short wavelength region side is smaller than the radiation energy of light on the light wavelength region side, and in addition to this, the spectral sensitivity of the photodetector 3 is also the above. As in the case of FIG. For this reason, in order to correct these losses, it is necessary to make a large amount of measurement light incident on the short wavelength region measurement unit 10A.
On the other hand, in the spectroscopic measurement device 1A of the present embodiment, as described above, in addition to the adjustment of the light amount of the measurement target light by the aperture diameter of the aperture 4, the concave reflector 7A for short wavelength region and the concave surface for long wavelength region The amount of measurement target light incident on the short wavelength region measurement unit 10A is further increased by the reflecting mirror 7B. For this reason, as described above, even when the light source 5 having low radiation energy in the short wavelength region is used and the photodetector 3 having low spectral sensitivity in the short wavelength region is used, the short wavelength region side of the measurement target light is measured. A lot of measurement target light can be made incident on the short wavelength region measurement unit 10A, and the measurement accuracy can be improved.

[Third embodiment]
Next, a spectrometer 1B according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 9 is a diagram showing a schematic configuration of the spectrometer 1B of the third embodiment.

  In the spectroscopic measurement device 1A of the second embodiment, the short wavelength concave mirror 7A and the long wavelength concave reflector 7B are provided one by one, and the areas Sa, Sb, By making the optical distances La1 and Lb1 different from each other, the amount of measurement target light incident on the short wavelength region measurement unit 10A was increased. On the other hand, in the spectroscopic measurement apparatus 1B of the third embodiment, as shown in FIG. 9, as the concave reflecting mirror for short wavelength region 7A and the concave reflecting mirror for long wavelength region 7B, Although the optical distance is the same, the quantity of the measurement target light to be incident on the short wavelength region measurement unit 10A is increased by changing the number of installed light beams.

Specifically, in the spectroscopic measurement device 1B, two short-wavelength-area concave reflecting mirrors 7A are provided to face the short-wavelength-area measuring unit 10A, and the long-wavelength-area measuring unit 10B is opposed to one long wavelength. A concave reflecting mirror for wavelength region 7B is provided. These two short-wavelength concave reflectors 7A and one long-wavelength concave reflector 7B have the same area of the surface reflection region to follow, are formed in the same shape, and have the same condensing distance. It becomes.
In such a spectroscopic measurement apparatus 1B of the third embodiment, the measurement target light reflected by one long-wavelength-area concave reflecting mirror 7B is incident on the long-wavelength-area measurement unit 10B, whereas the short wavelength Since the measurement target light reflected by the two short-wavelength concave reflecting mirrors 7A is incident on the measurement unit for area 10A, the light amount of the measurement target light incident on the measurement unit for short wavelength area 10A is a long wavelength. More than the amount of measurement target light incident on the area measurement unit 10B.

In the spectroscopic measurement device 1B of the third embodiment, the number of the short wavelength band concave reflecting mirrors 7A is two. However, the number is not limited thereto, and more short wavelength band concave reflecting mirrors 7A are provided. It is good also as a structure. Further, a plurality of concave reflecting mirrors 7B for the long wavelength region may be provided. In this case, as described above, the reflecting regions 71 of the concave reflecting mirror 7A for the short wavelength region and the concave reflecting mirror 7B for the long wavelength region are provided. Are the same as the concave reflectors 7B for short wavelengths, and the light reflected by the concave reflectors 7A for short wavelengths is provided with the same number of concave reflectors 7A for short wavelengths. Must pass through the short wavelength region measurement unit 10A.
Similarly to the second embodiment, the area of the first reflective region 71A of the concave reflector for short wavelength region 7A is made larger than the area of the second reflective region 71B of the concave reflector for long wavelength region 7B, The light amount of the measurement target light incident on the short wavelength region measuring unit 10A by making the condensing distance of the concave reflecting mirror for short wavelength region 7A shorter than the condensing distance of the concave reflecting mirror for long wavelength region 7B It is good also as a structure which increases more.

  Also in the third embodiment, the numbers of the short wavelength region concave reflecting mirror 7A and the long wavelength region concave reflecting mirror 7B are determined in substantially the same manner as the first embodiment and the second embodiment. That is, in the state in which the measurement light for white light is incident on the measurement unit for short wavelength region 10A and the measurement unit for long wavelength region 10B, the first wavelength of the maximum wavelength in the first measurement wavelength region is obtained by the short wavelength region etalon 2A. The wavelength light (500 nm) is taken out, and the second wavelength light (750 nm) having the maximum wavelength in the second measurement wavelength range is taken out by the long wavelength range etalon 2B. The magnitude of the short wavelength side detection signal output from the short wavelength region photodetector 3A and the magnitude of the long wavelength side detection signal output from the long wavelength region photodetector 3B are substantially the same. In addition, the number of concave reflecting mirrors 7A for short wavelength region and concave reflecting mirror 7B for long wavelength region is set.

[Operational effects of the third embodiment]
As described above, in the spectroscopic measurement apparatus 1B of the third embodiment, the two short wavelength band concave reflecting mirrors 7A are provided for the short wavelength band measuring unit 10A, and one long wavelength band measuring unit 10B is provided. A concave reflecting mirror for wavelength region 7B is provided. For this reason, in the short wavelength region measurement unit 10A in which the measurement target light is collected by the two short wavelength region concave reflecting mirrors 7A, the measurement target light is condensed by only one long wavelength region concave reflection mirror 7B. The amount of incident measurement target light is larger than that of the long wavelength region measurement unit 10B. For this reason, as in the first and second embodiments, in the photodetector 3, even when the spectral sensitivity on the short wavelength region side is low, the measurement can be performed with a large amount of light, so that the measurement accuracy Can be improved.

[Fourth embodiment]
Next, a spectrometer 1C according to a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 10 is a diagram showing a schematic configuration of the spectrometer according to the fourth embodiment of the present invention.

  In the second embodiment, the short wavelength region concave reflecting mirror 7A and the long wavelength region concave reflecting mirror 7B are provided facing the short wavelength region measuring unit 10A and the long wavelength region measuring unit 10B, and these concave surfaces are provided. The structure which adjusts the light quantity of measurement object light by varying the area of the reflective area | region 71 in the reflective mirror 7, and a condensing distance was shown. In contrast, in the fourth embodiment, the light quantity of the measurement target light is adjusted by using the condenser lens 8 instead of the concave reflecting mirror 7.

Specifically, in the spectroscopic measurement apparatus 1C, the short wavelength region as the first condenser lens that constitutes the first light amount adjustment unit of the present invention on the optical path from the measurement target A to the short wavelength region measurement unit 10A. 8A for collecting the long wavelength region as the second condensing lens, which constitutes the second light amount adjusting unit of the present invention on the optical path from the measuring object A to the measuring unit 10B for the long wavelength region. An optical lens 8B is provided.
Here, the short wavelength region condensing lens 8A, which is the first condensing lens, opposed to the short wavelength region measuring unit 10A, and the second condensing lens, which is opposed to the long wavelength region measuring unit 10B. The lens diameter and the lens curvature are different from those of the wavelength range condenser lens 8B.
That is, as shown in FIG. 10, the lens diameter Ra of the short wavelength region condensing lens 8A is formed larger than the lens diameter Rb of the long wavelength region condensing lens 8B. Thereby, in the short wavelength region condensing lens 8A, it becomes possible to condense more measurement target light on the short wavelength region measuring unit 10A than in the long wavelength region condensing lens 8B. The amount of the first wavelength light received by the detector 3A also increases.

Further, the short wavelength focusing lens 8A and the long wavelength focusing lens 8B have different lens curvatures, whereby the distance from the focusing lens 8 to the lens focus point where the measurement target light is focused ( Lens focusing distance) is different. Specifically, the distance from the lens center of the short wavelength region condensing lens 8A to the focus point (first lens focus point F3) of the short wavelength region condensing lens 8A (first lens condensing distance La2). Is longer than the distance (second lens focusing distance Lb2) from the center of the long wavelength focusing lens 8B to the focus point (second lens focusing point F4) of the focusing lens 8B for long wavelength. It is set short.
For this reason, among the measurement target light condensed by the short wavelength condensing lens 8A, the measurement target is emitted to the short wavelength etalon 2A side through the first opening 41 of the short wavelength aperture 4A. Of the light to be measured collected by the long wavelength condenser lens 8B, the amount of light passes through the second opening 42 of the long wavelength aperture 4B and exits toward the long wavelength etalon 2B. The amount of light to be measured is larger than the amount of light to be measured.

  Similarly to the first embodiment, the opening diameter of the first opening 41 of the short wavelength aperture 4A is larger than the opening diameter of the second opening of the long wavelength aperture 4B. The light quantity of the measurement target light incident on the wavelength range etalon 2A side is larger than the light quantity of the measurement target light incident on the long wavelength range etalon 2B side.

  As described above, the light amount of the measurement target light incident on the short wavelength region measurement unit 10A is larger than the light amount of the measurement target light incident on the long wavelength region measurement unit 10B. Further, in addition to the light amount adjustment by the aperture diameter of the aperture 4, the light amount adjustment is performed by the difference in the lens diameter of the condensing lens 8 and the lens condensing distance, thereby effectively reducing the short wavelength as in the second embodiment. The amount of measurement target light incident on the area measurement unit 10A can be increased.

  In the fourth embodiment, the lens diameters Ra and Rb of the short wavelength region condensing lens 8A and the long wavelength region condensing lens 8B and the lenses are substantially the same as in the first to third embodiments. The curvature (lens focusing distances La2 and Lb2) is determined. That is, in the state in which the measurement light for white light is incident on the measurement unit for short wavelength region 10A and the measurement unit for long wavelength region 10B, the first wavelength of the maximum wavelength in the first measurement wavelength region is obtained by the short wavelength region etalon 2A. The wavelength light (500 nm) is taken out, and the second wavelength light (750 nm) having the maximum wavelength in the second measurement wavelength range is taken out by the long wavelength range etalon 2B. The magnitude of the short wavelength side detection signal output from the short wavelength region photodetector 3A and the magnitude of the long wavelength side detection signal output from the long wavelength region photodetector 3B are substantially the same. In addition, the lens diameters Ra and Rb and the lens curvature are set.

[Effects of the fourth embodiment]
As described above, in the spectroscopic measurement apparatus 1C of the fourth embodiment, the short wavelength region condensing lens is disposed on the optical path of the measurement target light incident on the short wavelength region measurement unit 10A and the long wavelength region measurement unit 10B. 8A and a long wavelength condensing lens 8B are provided. And in these condensing lenses 8, the lens condensing distance of the short wavelength region condensing lens 8A is set shorter than the lens condensing distance of the long wavelength region condensing lens 8B.
For this reason, the amount of the measurement target light reflected by the short wavelength region condensing lens 8A and passing through the first opening 41 of the short wavelength region aperture 4A is reflected by the long wavelength region condensing lens 8B and is long. The amount of light to be measured passes through the second opening 42 of the wavelength band aperture 4B. Therefore, the amount of light of the measurement target light in the short wavelength range measured by the short wavelength range measurement unit 10A increases, and the amount of the first wavelength light extracted by the short wavelength range etalon 2A also increases. Thereby, in the photodetector 3, even if the spectral sensitivity on the short wavelength region side is low, the measurement can be performed with a large amount of light, so that the measurement accuracy can be improved.

In the spectroscopic measurement apparatus 1C, in the condensing lens 8, the lens diameter Ra of the short wavelength region condensing lens 8A is set larger than the lens diameter Rb of the long wavelength region condensing lens 8B.
For this reason, in the short wavelength region condensing lens 8A, it is possible to condense more measurement target light on the short wavelength region measuring unit 10A than in the long wavelength region condensing lens 8B. Thereby, in the photodetector 3 for a short wavelength region, even when the spectral sensitivity on the short wavelength region side is low, measurement can be performed with a large amount of light, so that the measurement accuracy can be improved.

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

  For example, in the second to third embodiments, the opening diameter of the first opening 41 of the short wavelength aperture 4A is larger than the opening diameter of the second opening 42 of the long wavelength aperture 4B. However, the configuration is such that more measurement target light can be incident, but the present invention is not limited to this. For example, the opening diameter of the opening of the aperture 4 (4A, 4B) may be configured to have the same diameter or may be configured such that the aperture 4 is not provided. Even in this case, the measurement target incident on the short wavelength region measuring unit 10A and the long wavelength region measuring unit 10B by the concave reflecting mirror 7 (7A, 7B) and the condenser lens 8 (8A, 8B). It is possible to adjust the amount of light.

In the second embodiment, the concave reflecting mirror 7 (7A, 7B) is incident on the short wavelength region measuring unit 10A by making both the concave reflecting mirror area and the concave curvature (condensing distance) different. For example, the configuration may be such that only one of the area of the concave reflecting mirror area and the concave curvature is different.
Similarly, in the fourth embodiment, in the condensing lens 8 (8A, 8B), by making both the lens diameter and the lens curvature (lens condensing distance) different, the measurement is made incident on the short wavelength region measuring unit 10A. Although it was set as the structure which increases the light quantity of object light, the structure from which either one differs among a lens diameter and a lens curvature may be sufficient, for example.

  Furthermore, in 2nd-3rd embodiment, it is good also as a structure which arrange | positions the condensing lens 8 like 4th embodiment further on the optical path of measurement object light. Even in this case, it is possible to increase the amount of measurement target light in the first measurement unit.

  Furthermore, in 1st-4th embodiment, although the 1st opening part 41 and the 2nd opening part 42 of the aperture 4 (4A, 4B) illustrated the structure to which opening diameter Da and Db are fixed, respectively, It is not limited. For example, the aperture 4 (4A, 4B) may have an iris diaphragm so that the opening diameter of the opening can be changed.

In the first to fourth embodiments, the spectrometers 1, 1 </ b> A, 1 </ b> B, and 1 </ b> C have the short wavelength region measurement unit 10 </ b> A whose measurement target is the short wavelength region side of the measurement target light and the long wavelength region side. Although the configuration includes the two measurement units 10 including the measurement unit 10B for the long wavelength region that is the measurement target, a configuration including more measurement units may be employed.
For example, among the measurement target light, a short wavelength region measurement unit whose measurement target is a short wavelength region of 350 to 500 nm, a medium wavelength region measurement unit whose measurement target is a medium wavelength region of 500 to 650 nm, and 650 nm to It is good also as a structure provided with the measurement part for long wavelength regions which made the long wavelength region of 800 nm the measuring object. In this case, focusing on the relationship between the short wavelength region measurement unit and the medium wavelength region measurement unit, the short wavelength region etalon, the short wavelength region photodetector, and the short wavelength region light quantity in the short wavelength region measurement unit An adjustment unit (for example, an aperture, a concave reflecting mirror, a condensing lens, etc.) constitutes the first light filter, the first photodetector, and the first light amount adjustment unit of the present invention, and the medium wavelength in the measurement unit for medium wavelength region The etalon for the wavelength range, the photodetector for the middle wavelength range, and the light amount adjustment section for the middle wavelength range (for example, an aperture, a concave reflecting mirror, a condensing lens, etc.) And a second light quantity adjustment unit. Focusing on the relationship between the measurement unit for the medium wavelength region and the measurement unit for the long wavelength region, the etalon for the medium wavelength region, the photodetector for the medium wavelength region, and the light amount adjustment for the medium wavelength region in the measurement unit for the medium wavelength region Parts (for example, an aperture, a concave reflecting mirror, a condensing lens, etc.) constitute the first optical filter, the first photodetector, and the first light quantity adjusting unit of the present invention, and the long wavelength region in the long wavelength region measuring unit Etalon, long-wavelength region photodetector, and long-wavelength region light amount adjusting unit (for example, an aperture, a concave reflecting mirror, a condensing lens, etc.), the second optical filter of the present invention, the second photodetector, and A second light amount adjustment unit is configured.
In such a configuration, the amount of measurement target light incident on the short wavelength region measurement unit is set to be larger than the amount of measurement target light incident on the medium wavelength region measurement unit, and the medium wavelength region measurement unit By making the amount of incident measurement target light greater than the amount of measurement target light incident on the long wavelength range measurement unit, it is possible to detect a more accurate received light amount for each wavelength range, and further measure Accuracy can be improved.

  Furthermore, although the etalon 2 was illustrated as a 1st optical filter and a 2nd optical filter, it is not limited to this. For example, a configuration in which light to be measured is dispersed by a prism or the like, and each dispersed light is received by the photodetector 3, a configuration in which only light having a desired wavelength is extracted by a color filter or the like, and received by the photodetector 3, etc. It is good.

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

  DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C ... Spectrometer as a light measuring device, 2A ... Short wavelength etalon as first optical filter, 2B ... Long wavelength etalon as second optical filter, 3A ... First light Short wavelength region photodetector as a detector, 3B... Long wavelength region photodetector as a second photodetector, 4A... Short wavelength aperture as a first aperture constituting the first light quantity adjustment unit, 4B: Long wavelength range aperture as the second aperture constituting the second light quantity adjustment unit, 5 ... Light source, 7A ... Concave reflector for short wavelength range as the first concave reflection mirror constituting the first light quantity adjustment unit, 7B: a concave reflecting mirror for a long wavelength region as a second concave reflecting mirror constituting the second light amount adjusting unit, 8A: a condensing lens for a short wavelength region as a first condensing lens constituting the first light amount adjusting unit, 8B ... The second light quantity adjustment unit constituting the second light quantity adjustment unit A condensing lens for a long wavelength region as a condensing lens, 21 ... first substrate, 22 ... second substrate, 23 ... first reflecting film, 24 ... second reflecting film, 25 ... electrostatic actuator, 71A ... first reflecting Area, 71B, second reflection area, F1, first focus point, F2, second focus point, F3, first lens focus point, F4, second lens focus point.

Claims (10)

Of the measurement target light, a first optical filter that extracts light of the first wavelength within the first measurement wavelength range;
Of the measurement target light, a second optical filter that extracts light of the second wavelength in the second measurement wavelength range that is longer than the first measurement wavelength range,
A first light amount adjustment unit for adjusting the light amount of the measurement target light incident on the first light filter;
A second light amount adjustment unit for adjusting the light amount of the measurement target light incident on the second light filter;
A first photodetector that receives the amount of light of the first wavelength extracted by the first optical filter and outputs a detection signal according to the amount of received light;
A second photodetector that receives the amount of light of the second wavelength extracted by the second optical filter and outputs a detection signal according to the amount of received light;
Comprising
The amount of light incident on the first light filter adjusted by the first light amount adjustment unit is adjusted by the second light amount adjustment unit than the amount of light incident on the second light filter. A light measuring device that is large. The light measurement apparatus according to claim 1,
The first light amount adjustment unit includes a first aperture having a first opening for reducing the light amount of the measurement target light incident on the first light filter,
The second light amount adjustment unit includes a second aperture having a second opening that restricts the light amount of the measurement target light incident on the second light filter,
The optical measurement apparatus, wherein the first opening of the first aperture has an opening diameter larger than that of the second opening of the second aperture. In the optical measurement device according to claim 1 or 2,
The first light amount adjustment unit includes a first concave reflecting mirror that reflects and collects the measurement target light toward a first focus point and enters the first light filter,
The second light amount adjustment unit includes a second concave reflecting mirror that reflects and collects the measurement target light toward a second focus point and enters the second light filter.
The first condensing distance from the first concave reflecting mirror to the first focus point is shorter than the second condensing distance from the second concave reflecting mirror to the second focus point. apparatus. In the optical measuring device according to any one of claims 1 to 3,
The first light amount adjustment unit includes a first concave reflecting mirror that reflects and collects the measurement target light incident on the first reflection region and enters the first light filter,
The second light amount adjustment unit includes a second concave reflecting mirror that reflects and collects the measurement target light incident on the second reflection region and causes the measurement target light to enter the second light filter.
The optical measurement apparatus, wherein the first reflection area of the first concave reflecting mirror is larger than the second reflection area of the second concave reflecting mirror. In the optical measurement device according to any one of claims 1 to 4,
The first light amount adjustment unit includes a plurality of first concave reflecting mirrors that reflect and collect the measurement target light and enter the first light filter,
The second light amount adjustment unit includes at least one second concave reflecting mirror that reflects and collects the measurement target light and enters the second light filter,
The number of the first concave reflecting mirrors of the first light amount adjusting unit is larger than the number of the second concave reflecting mirrors of the second light amount adjusting unit. In the optical measurement device according to claim 1 or 2,
The first light amount adjustment unit includes a first condenser lens that condenses the measurement target light toward a first lens focus point and enters the first light filter,
The second light amount adjustment unit includes a second condensing lens that condenses the measurement target light toward a second lens focus point and enters the second light filter.
The first lens focusing distance from the first focusing lens to the first lens focusing point is shorter than the second lens focusing distance from the second focusing lens to the second lens focusing point. A light measuring device. In the optical measurement device according to any one of claims 1, 2, and 6,
The first light amount adjustment unit includes a first condenser lens that condenses the measurement target light incident within a first lens diameter and causes the measurement target light to enter the first light filter,
The second light amount adjustment unit includes a second condensing lens that condenses the measurement target light incident within the second lens diameter and enters the second light filter,
The first lens diameter of the first condenser lens is larger than the second lens diameter of the second condenser lens. The light measurement device according to any one of claims 1 to 7,
A light source that irradiates light to the measurement object
Said 1st light quantity adjustment part and said 2nd adjustment part adjust the light quantity of the measurement object light inject | emitted from the said light source, and reflected by the said measurement object. The optical measurement apparatus characterized by the above-mentioned. In the optical measuring device according to any one of claims 1 to 8,
The first light filter and the second light filter are:
A first substrate;
A second substrate facing the first substrate;
A first reflective film provided on the first substrate;
A second reflective film provided on the second substrate and facing the first reflective film;
An electrostatic actuator that varies a gap interval between the first reflective film and the second reflective film;
An optical measurement device comprising: The light measurement device according to any one of claims 1 to 9,
The light to be measured is visible light, and the first measurement wavelength region and the second measurement wavelength region include a visible light region.

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