JP2016090251A - Spectrometer and spectroscopic method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spectrometer and a spectrometric method capable of achieving high-accuracy spectrometry.SOLUTION: A spectrometer 1 includes: a wavelength variable interference filter 5 having a pair of reflection films opposing to each other, which allows light at a wavelength depending on a gap dimension between the reflection films to exit from the light incident to the pair of reflection films; an incident optical system 11 that guides measurement light originated from illumination light for irradiating a measurement target X and reflected by the measurement target X, and reference light originated from the illumination light and not involved with the measurement target X, separately through the respective optical paths to the wavelength variable interference filter 5; and a light-receiving unit 12 that receives each of the measurement light and the reference light exiting from the wavelength variable interference filter 5. The incident optical system 11 guides the measurement light to be incident to the wavelength variable interference filter 5 with a main optical axis L1 of the measurement light inclined by an inclination angle θ relative to an optical axis O, and guides the reference light to be incident to the wavelength variable interference filter 5 with a main optical axis L2 of the reference light inclined by an inclination angle θ relative to the optical axis O.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a spectroscopic measurement apparatus and a spectroscopic measurement method.

2. Description of the Related Art Conventionally, there is known an apparatus that performs spectroscopic measurement by irradiating a measurement target with illumination light from a light source and dispersing the reflected light of the measurement target (for example, see Patent Document 1).
In the apparatus described in Patent Document 1, the reference spectral intensity of illumination light is measured prior to measurement, and a data table for correcting each measurement wavelength is acquired in advance based on the elapsed time since the light source is turned on. To do. And the measurement result acquired by actual measurement is correct | amended using the elapsed time after lighting and the said data table.

JP 2008-298579 A

  By the way, the apparatus of patent document 1 measures the spectral intensity of illumination light prior to the measurement, and corrects the change in spectral intensity with the elapsed time from illumination light irradiation based on the data table. However, the amount of illumination light measured prior to measurement and the amount of illumination light at the time of actual measurement must be completely the same due to slight changes in drive voltage to the illumination light and environmental changes. There is no error. Therefore, even if the measurement result is corrected using the data table, there is a problem that the measurement accuracy is lowered due to the error.

  An object of the present invention is to provide a spectroscopic measurement apparatus and a spectroscopic measurement method capable of performing spectroscopic measurement with high accuracy.

  A spectroscopic measurement apparatus according to an application example of the invention includes a pair of reflective films facing each other, and emits light having a wavelength according to a gap dimension between the reflective films from light incident on the pair of reflective films. The interference filter to be measured, the measurement light reflected by the measurement object with the illumination light irradiated on the measurement object, and the reference light that is the illumination light not passing through the measurement object are guided to the interference filter through separate optical paths. An incident optical system; and a light receiving unit that receives each of the measurement light and the reference light emitted from the interference filter, and the incident optical system uses a main optical axis of the measurement light as an optical axis of the interference filter. The reference light is incident on the interference filter at a predetermined angle, and the main optical axis of the reference light is incident on the interference filter at a predetermined angle with respect to the optical axis of the interference filter. The features.

Here, the reference light that is illumination light that does not pass through the measurement target is illumination light that is applied to the measurement target. For example, in the case of performing spectroscopic measurement of the measurement target using light from the light source unit, the reference light is applied from the light source unit. When the spectroscopic measurement of the measurement object is performed using external light, the external light becomes reference light.
In this application example, the measurement light and the reference light are guided to the interference filter by separate optical paths by the incident optical system, and are tilted at the same tilt angle with respect to the optical axis of the interference filter (axis orthogonal to the pair of reflection films). Is incident. Therefore, the measurement light and the reference light emitted from the interference filter have the same wavelength, and these are received by the light receiving unit, respectively, so that the light quantity of the measurement light and the reference light quantity corresponding to the gap dimension between the reflection films And can be acquired at the same time. As described above, by acquiring the light amount of the reference light when the measurement light is measured, it is possible to suppress the influence due to the temporal change of the illumination light, and it is possible to perform highly accurate spectroscopic measurement.

In the spectroscopic measurement device according to this application example, it is preferable that a plane including the optical axis of the interference filter and the main optical axis of the measurement light is different from a plane including the optical axis of the interference filter and the main optical axis of the reference light. .
In this application example, the plane (measurement light surface) including the optical axis of the interference filter and the main optical axis of the measurement light is different from the plane (reference light surface) including the optical axis of the interference filter and the main optical axis of the reference light. It is a plane. That is, the measurement light surface and the reference light surface intersect each other. In other words, the incident optical system guides the measurement light and the reference light to the interference filter so that the optical path of the reference light and the optical path of the measurement light are asymmetric when viewed from the optical axis direction of the interference filter.
In such a configuration, it is possible to suppress the disadvantage that the reference light is reflected by the interference filter and enters the optical path of the measurement light and becomes stray light. That is, when the measurement light surface and the reference light surface are the same (the optical path of the measurement light and the optical path of the reference light are symmetric when viewed from the optical axis direction of the interference filter), the incident angle of the reference light to the interference filter, Since the incident angle of the measurement light is the same angle, the reference light may be regularly reflected on the optical path of the measurement light. In this case, the reference light that has entered the measurement light is reflected by the measurement target, and becomes a stray light component. On the other hand, in this application example, since the measurement light surface and the reference light surface are different surfaces, the inconvenience that the reference light becomes stray light can be suppressed, and the measurement accuracy can be improved.

In the spectroscopic measurement device according to this application example, it is preferable that the light receiving unit includes a light receiving element for measuring light that receives the measurement light and a light receiving element for reference light that receives the reference light.
In this application example, the measurement light is received by the measurement light receiving element, and the reference light is received by the reference light receiving element. In such a configuration, the light amounts of the measurement light and the reference light can be individually and accurately detected by the measurement light receiving element and the reference light receiving element. That is, it is possible to suppress the inconvenience that the reference light is received by the measurement light receiving element or the measurement light is received by the reference light receiving element, and the measurement accuracy can be improved. In addition, the measurement light receiving element may be arranged on the optical path of the measurement light emitted from the interference filter, and the measurement light receiving element may be arranged on the optical path of the reference light emitted from the interference filter. It is possible to omit or simplify the arrangement of an optical system (for example, a lens or the like) for guiding each light.

In the spectroscopic measurement apparatus according to this application example, the light receiving element for measurement light includes a plurality of pixels, and is an image pickup element that captures an image of the measurement light output from the interference filter, and is on an optical path of the measurement light. It is preferable that an image forming optical system for forming an image on the image sensor is provided.
In this application example, an image sensor is used as the light receiving element for measurement light, and the measurement light is imaged on the image sensor by the imaging optical system. Thereby, the spectral image of a measuring object can be acquired.

In the spectroscopic measurement apparatus according to this application example, it is preferable that the light receiving unit is an imaging element having a plurality of pixels, and includes a measurement pixel region for detecting the measurement light and a reference pixel region for detecting the reference light. .
In this application example, the measurement light and the light receiving unit are received by one image sensor, and in this image sensor, a measurement pixel region that receives the measurement light and a reference pixel region that receives the reference light are provided. In such a configuration, the light amounts of the measurement light and the reference light can be detected by one image sensor, and the configuration can be simplified. In addition, when the light receiving unit for measurement light and the light receiving unit for reference light are separated, there is a possibility that measurement accuracy may be lowered due to a difference in light receiving characteristics of each light receiving unit. On the other hand, in this application example, the measurement light and the reference light can be received by the imaging device having the same light receiving characteristics, and the measurement accuracy can be improved.

  In the spectroscopic measurement apparatus according to this application example, the reference measurement light reflected by the standard white object is received by the light receiving unit and output, and the reference light is output when the reference measurement value is output. Reference value acquisition means for acquiring a reference reference value received and output by the light receiving unit, target measurement value that is output when the measurement light reflected by the measurement target is received by the light receiving unit, and the target measurement Target value acquisition means for acquiring a target reference value that is received and output by the light receiving unit when a value is output; the standard measurement value; the standard reference value; the target measurement value; and It is preferable that the apparatus includes a reflectance measurement unit that calculates the reflectance of each wavelength of the measurement target using a target reference value.

In this application example, the reference value acquisition unit acquires the amount of measurement light (standard measurement value) for the standard white object and the amount of reference light (standard reference value) when the reference measurement value is acquired. Further, the target value acquisition means acquires the light amount of the measurement light (target measurement value) for the measurement target and the light amount of the reference light (target reference value) when the target measurement value is acquired. Then, the reflectance measurement means measures (calculates) the reflectance of each wavelength of the measurement target based on the standard measurement value, the standard reference value, the target measurement value, and the target reference value.
In such a configuration, the reflectance of the measurement target calculated by the target measurement value for the measurement light and the standard measurement value for the standard white target can be calculated, and further, the target reference value and the standard reference value are used to calculate the target. It is possible to correct the difference between the amount of illumination light at the timing when the measurement value is measured and the amount of illumination light at the timing when the standard white object is measured.
As a result, the reflectance of the measurement object can be calculated with the same illumination light condition applied to the measurement object, and the measurement accuracy can be further improved.

  A spectroscopic measurement method according to an application example of the present invention includes a pair of reflective films facing each other, and emits light having a wavelength according to a gap dimension between the reflective films from light incident on the pair of reflective films. The interference filter to be measured, the measurement light reflected by the measurement object with the illumination light irradiated on the measurement object, and the reference light that is the illumination light not passing through the measurement object are guided to the interference filter through separate optical paths. An incident optical system; and a light receiving unit that receives the measurement light and the reference light emitted from the interference filter, respectively, and the incident optical system uses the main optical axis of the measurement light as the optical axis of the interference filter. The main optical axis of the reference light is inclined by the predetermined angle with respect to the optical axis of the interference filter and incident on the interference filter. A spectroscopic measurement method in a measuring apparatus, wherein a reference measurement light reflected by a standard white object is received by the light receiving unit and output, and the reference light is output when the reference measurement value is output. A reference reference value that is received and output by the light receiving unit is acquired, and the measurement light reflected by the measurement target is received by the light receiving unit and output, and the target measurement value is output. When the reference light is received by the light receiving unit and is output, the target reference value is acquired, and the measurement is performed using the standard measurement value, the standard reference value, the target measurement value, and the target reference value. The reflectance of each wavelength of the object is calculated.

  In this application example, the standard measurement value and the standard reference value can be acquired simultaneously, and the target measurement value and the target reference value can be acquired simultaneously. Therefore, by obtaining the reflectance using these standard measurement value, standard reference value, target measurement value, and target reference value, it is possible to perform spectroscopic measurement with high accuracy.

1 is a block diagram showing a schematic configuration of a spectrometer according to a first embodiment of the present invention. The top view which shows schematic structure of the wavelength variable interference filter in 1st embodiment. Sectional drawing which shows schematic structure of the wavelength variable interference filter in 1st embodiment. The flowchart which shows the spectrometry method in 1st embodiment. The figure which shows schematic structure of the optical module of 2nd embodiment which concerns on this invention. The figure which shows schematic structure of the optical module of 3rd embodiment which concerns on this invention. The figure which shows schematic structure of the optical module of 4th embodiment which concerns on this invention. The block diagram which shows schematic structure of the spectrometer of 5th embodiment which concerns on this invention. The flowchart which shows the spectrometry method of 5th embodiment.

[First embodiment]
Hereinafter, a spectroscopic measurement apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of the spectrometer according to the first embodiment of the present invention.
As shown in FIG. 1, the spectroscopic measurement apparatus 1 includes an optical module 10, a filter control circuit 20, a signal processing circuit 30, and a control unit 40.
The spectroscopic measurement device 1 irradiates the measurement target X from the light source 2 with illumination light, receives the illumination light reflected by the measurement target X as measurement light, and receives the illumination light from the light source 2. Is received directly by the optical module 10 (without passing through the measurement target X). Then, the light amount (measurement value) of the measurement light and the reference light is output from the optical module 10 to the control unit 40 via the signal processing circuit 30, and the control unit 40 determines the measurement target X based on these measurement values. Perform spectroscopic measurements.
The light source 2 may be, for example, outside light or the like in addition to a tungsten lamp, an LED light source, or the like. Further, FIG. 1 shows an example in which the light source 2 and the spectroscopic measurement device 1 are configured separately, but the present invention is not limited thereto, and when the light source unit such as a tungsten lamp or an LED light source is used as the light source 2, the spectroscopic measurement device 1 A light source unit may be incorporated in the device. In this case, the control of the light source unit may be performed by the control unit 40.

[Configuration of optical module]
The optical module 10 includes a variable wavelength interference filter 5 (interference filter of the present invention), an incident optical system 11, and a light receiving unit 12.
The optical module 10 guides the measurement light and the reference light to the variable wavelength interference filter 5 by the incident optical system 11, and receives the measurement light and the reference light emitted (transmitted) from the variable wavelength interference filter 5 by the light receiving unit 12.

[Configuration of wavelength tunable interference filter]
FIG. 2 is a plan view showing a schematic configuration of the variable wavelength interference filter 5. FIG. 3 is a cross-sectional view showing a schematic configuration of the variable wavelength interference filter 5 cut along the line AA in FIG.
As shown in FIGS. 2 and 3, the variable wavelength interference filter 5 includes a fixed substrate 51 and a movable substrate 52. The fixed substrate 51 and the movable substrate 52 are each formed of, for example, various types of glass, quartz, or the like. In the present embodiment, the fixed substrate 51 and the movable substrate 52 are configured of quartz glass. Then, as shown in FIG. 3, these substrates 51 and 52 are integrally formed by being bonded by a bonding film 53 (first bonding film 531 and second bonding film 532). Specifically, the first bonding portion 513 of the fixed substrate 51 and the second bonding portion 523 of the movable substrate 52 are bonded by a bonding film 53 made of, for example, a plasma polymerized film mainly containing siloxane. .
In the following description, the wavelength tunable interference filter 5 was seen from a plan view seen from the thickness direction of the fixed substrate 51 or the movable substrate 52, that is, from the stacking direction of the fixed substrate 51, the bonding film 53, and the movable substrate 52. The plan view is referred to as a filter plan view.

As shown in FIG. 3, the fixed substrate 51 is provided with a fixed reflective film 54 constituting one of the pair of reflective films of the present invention. The movable substrate 52 is provided with a movable reflective film 55 that constitutes the other of the pair of reflective films of the present invention. The fixed reflection film 54 and the movable reflection film 55 are disposed to face each other via the inter-reflection film gap G1.
The wavelength variable interference filter 5 is provided with an electrostatic actuator 56 that is a gap changing portion of the present invention and is used to adjust the distance (gap size) of the gap G1 between the reflective films 54 and 55. . The electrostatic actuator 56 includes a fixed electrode 561 provided on the fixed substrate 51 and a movable electrode 562 provided on the movable substrate 52, and each electrode 561 and 562 are opposed to each other. These fixed electrode 561 and movable electrode 562 are opposed to each other through an interelectrode gap. Here, the electrodes 561 and 562 may be provided directly on the substrate surfaces of the fixed substrate 51 and the movable substrate 52, respectively, or may be provided via other film members.
In the present embodiment, the configuration in which the gap G1 between the reflection films is formed smaller than the gap between the electrodes is exemplified. However, depending on the wavelength range transmitted by the wavelength variable interference filter 5, for example, the gap G1 between the reflection films is formed between the electrodes. You may form larger than a gap.
Further, in the filter plan view, one side of the movable substrate 52 (for example, the side C <b> 3-C <b> 4 in FIG. 2) protrudes outside the side C <b> 3 ′ -C <b> 4 ′ of the fixed substrate 51. The protruding portion of the movable substrate 52 is an electrical component 526 that is not bonded to the fixed substrate 51, and the surfaces exposed when the variable wavelength interference filter 5 is viewed from the fixed substrate 51 side are provided with electrode pads 564P and 565P described later. The electrical surface 524 is obtained.
Similarly, in the filter plan view, one side of the fixed substrate 51 (the side opposite to the electrical component 526) protrudes outside the movable substrate 52.

(Configuration of fixed substrate)
In the fixed substrate 51, an electrode arrangement groove 511 and a reflection film installation part 512 are formed by etching. The fixed substrate 51 is formed to have a thickness larger than that of the movable substrate 52, and the fixed substrate is caused by electrostatic attraction when a voltage is applied between the fixed electrode 561 and the movable electrode 562 or internal stress of the fixed electrode 561. There is no 51 deflection.

  The electrode arrangement groove 511 is formed in an annular shape centering on the filter center point of the fixed substrate 51 in the filter plan view. The reflection film installation part 512 is formed so as to protrude from the center part of the electrode arrangement groove 511 toward the movable substrate 52 in the plan view. The groove bottom surface of the electrode arrangement groove 511 is an electrode installation surface 511A on which the fixed electrode 561 is arranged. In addition, the protruding front end surface of the reflection film installation portion 512 is a reflection film installation surface 512A.

A fixed electrode 561 constituting the electrostatic actuator 56 is provided on the electrode installation surface 511A. The fixed electrode 561 is provided in a region of the electrode installation surface 511 </ b> A that faces a movable electrode 562 of the movable portion 521 described later. In addition, an insulating film for ensuring insulation between the fixed electrode 561 and the movable electrode 562 may be stacked over the fixed electrode 561.
The fixed substrate 51 is provided with a fixed extraction electrode 563 connected to the outer peripheral edge of the fixed electrode 561. The fixed extraction electrode 563 is provided along a connection electrode groove (not shown) formed from the electrode arrangement groove 511 toward the side C3′-C4 ′ (electrical component 526 side). The connection electrode groove is provided with a bump portion 565A that protrudes toward the movable substrate 52, and the fixed extraction electrode 563 extends over the bump portion 565A. Then, the bumps 565A abut against the fixed connection electrodes 565 provided on the movable substrate 52 side and are electrically connected. The fixed connection electrode 565 extends from the region facing the connection electrode groove to the electrical surface 524, and forms a fixed electrode pad 565P on the electrical surface 524.

  In the present embodiment, a configuration is shown in which one fixed electrode 561 is provided on the electrode installation surface 511A. For example, a configuration in which two concentric circles centering on the filter center point are provided (double electrode configuration). And so on. In addition, a configuration in which a transparent electrode is provided on the fixed reflective film 54 or a conductive fixed reflective film 54 may be used to form a connection electrode from the fixed reflective film 54 to the fixed-side electrical component. In this case, the fixed electrode 561 may have a structure in which a part thereof is cut off in accordance with the position of the connection electrode.

As described above, the reflective film installation portion 512 is formed in a substantially cylindrical shape that is coaxial with the electrode arrangement groove 511 and has a smaller diameter than the electrode arrangement groove 511, and is formed on the movable substrate 52 of the reflection film installation portion 512. An opposing reflection film installation surface 512A is provided.
As shown in FIG. 3, a fixed reflection film 54 is installed in the reflection film installation portion 512. As the fixed reflective film 54, for example, a metal film such as Ag or an alloy film such as an Ag alloy can be used. For example, a dielectric multilayer film in which the high refractive layer is TiO ₂ and the low refractive layer is SiO ₂ may be used. Further, a reflective film in which a metal film (or alloy film) is laminated on a dielectric multilayer film, a reflective film in which a dielectric multilayer film is laminated on a metal film (or alloy film), a single refractive layer (TiO ₂ , SiO ₂₎ and a metal film (or alloy film) and the like may be used reflective film formed by laminating a.

  Further, an antireflection film may be formed at a position corresponding to the fixed reflection film 54 on the light incident surface of the fixed substrate 51 (the surface on which the fixed reflection film 54 is not provided). This antireflection film can be formed by alternately laminating a low refractive index film and a high refractive index film, and reduces the reflectance of visible light on the surface of the fixed substrate 51 and increases the transmittance.

  Of the surfaces of the fixed substrate 51 facing the movable substrate 52, the surfaces on which the electrode placement groove 511, the reflective film installation portion 512, and the connection electrode groove are not formed by etching constitute the first bonding portion 513. The first bonding portion 513 is provided with a first bonding film 531. By bonding the first bonding film 531 to the second bonding film 532 provided on the movable substrate 52, as described above, The fixed substrate 51 and the movable substrate 52 are joined.

(Configuration of movable substrate)
The movable substrate 52 includes a circular movable portion 521 centered on the filter center point, and a holding portion 522 that is coaxial with the movable portion 521 and holds the movable portion 521.

The movable part 521 is formed with a thickness dimension larger than that of the holding part 522. The movable portion 521 is formed to have a diameter larger than at least the diameter of the outer peripheral edge of the reflection film installation surface 512A in the filter plan view. The movable part 521 is provided with a movable electrode 562 and a movable reflective film 55.
Similar to the fixed substrate 51, an antireflection film may be formed on the surface of the movable portion 521 opposite to the fixed substrate 51. Such an antireflection film can be formed by alternately laminating a low refractive index film and a high refractive index film, reducing the reflectance of visible light on the surface of the movable substrate 52 and increasing the transmittance. Can be made.

  The movable electrode 562 is opposed to the fixed electrode 561 with a predetermined inter-electrode gap, and is formed in an annular shape having the same shape as the fixed electrode 561. The movable electrode 562 forms an electrostatic actuator 56 together with the fixed electrode 561. The movable substrate 52 is provided with a movable connection electrode 564 connected to the outer peripheral edge of the movable electrode 562. The movable connection electrode 564 is provided across the electrical surface 524 from the movable part 521 along a position facing a connection electrode groove (not shown) provided in the fixed substrate 51, and is movable on the electrical surface 524. An electrode pad 564P is formed.

  Further, as described above, the fixed connection electrode 565 is provided on the movable substrate 52, and the fixed connection electrode 565 is connected to the fixed extraction electrode 563 via the bump portion 565A (see FIG. 2). .

The movable reflective film 55 is provided in the central part of the movable surface 521A of the movable part 521 so as to face the fixed reflective film 54 via the gap G1. As the movable reflective film 55, a reflective film having the same configuration as that of the fixed reflective film 54 described above is used.
In the present embodiment, as described above, an example in which the interelectrode gap is larger than the dimension of the inter-reflection film gap G1 is shown, but the present invention is not limited to this. For example, when using infrared rays or far-infrared rays, the gap G1 may be larger than the gap between the electrodes depending on the spectral wavelength acquisition target wavelength range.

The holding part 522 is a diaphragm that surrounds the periphery of the movable part 521, and has a thickness dimension smaller than that of the movable part 521. Such a holding part 522 is easier to bend than the movable part 521, and the movable part 521 can be displaced toward the fixed substrate 51 by a slight electrostatic attraction. At this time, since the movable portion 521 has a thickness dimension larger than that of the holding portion 522 and becomes rigid, even when the holding portion 522 is pulled toward the fixed substrate 51 by electrostatic attraction, the shape of the movable portion 521 changes. Absent. Therefore, the movable reflective film 55 provided on the movable portion 521 is not bent, and the fixed reflective film 54 and the movable reflective film 55 can be always maintained in a parallel state.
In the present embodiment, the diaphragm-like holding portion 522 is illustrated, but the present invention is not limited to this. For example, a configuration in which beam-like holding portions arranged at equiangular intervals around the filter center point are provided. It is good.

  In the movable substrate 52, a region facing the first joint portion 513 is a second joint portion 523. The second bonding portion 523 is provided with the second bonding film 532. As described above, the second bonding film 532 is bonded to the first bonding film 531, so that the fixed substrate 51 and the movable substrate 52 are bonded. Is done.

[Configuration of incident optical system]
Returning to FIG. 1, the incident optical system 11 includes a measurement light incident optical system 111 and a reference light incident optical system 112.
The measurement light incident optical system 111 receives the measurement light reflected by the measurement target X and guides the measurement light to the wavelength variable interference filter 5. Here, the measurement light incident optical system 111 passes through the optical axis O of the wavelength tunable interference filter 5 (that is, the axis perpendicular to the reflection films 54 and 55 through the center point (filter center point) of the reflection films 54 and 55). ) And the main optical axis L1 of the measurement light are configured so that each optical member such as a lens constituting the measurement light incident optical system 111 is configured to have a predetermined inclination angle θ.

  The reference light incident optical system 112 receives the reference light from the light source 2 and guides the reference light to the wavelength variable interference filter 5. Here, in the reference light incident optical system 112, the angle formed between the optical axis O of the wavelength tunable interference filter 5 and the main optical axis L2 of the reference light is the light of the main optical axis L1 of the measurement light and the wavelength tunable interference filter 5 Each optical member such as a lens constituting the reference light incident optical system 112 is configured to have the same inclination angle θ as that formed by the axis O.

  That is, the measurement light and the reference light are incident on the reflection films 54 and 55 of the wavelength tunable interference filter 5 from the separate optical paths at an inclination angle θ. Since the incident angles to the reflection films 54 and 55 are the same, the wavelength of the measurement light transmitted through the wavelength variable interference filter 5 and the wavelength of the reference light are also the same wavelength.

[Configuration of light receiving unit]
The light receiving unit 12 includes a light receiving element 121 for measurement light and a light receiving element 122 for reference light.
The light receiving element 121 for measurement light is provided on the optical path of the measurement light that has passed through the wavelength variable interference filter 5 and receives the measurement light. Then, the measurement light receiving element 121 outputs a detection signal (measurement value) corresponding to the amount of measurement light received to the signal processing circuit 30. The detection signal is subjected to signal processing such as amplification in the signal processing circuit 30 and then output to the control unit 40.
The reference light receiving element 122 is provided on the optical path of the reference light transmitted through the wavelength variable interference filter 5 and receives the reference light measurement light. Then, the reference light receiving element 122 outputs a detection signal (reference value) corresponding to the amount of received reference light to the signal processing circuit 30.

[Configuration of filter control circuit and signal processing circuit]
The filter control circuit 20 is connected to the electrode pads 564 </ b> P and 565 </ b> P of the wavelength variable interference filter 5, and applies a drive voltage to the electrostatic actuator 56 based on a command from the control unit 40. As a result, the gap G1 between the reflection films 54 and 55 is changed to a predetermined size corresponding to the drive voltage, and light (measurement light and reference light) having a wavelength corresponding to the gap G1 is transmitted from the wavelength variable interference filter 5. .

The signal processing circuit 30 amplifies each detection signal (analog signal) input from the light receiving unit 12, converts it to a digital signal, and outputs it to the control unit 40. For example, when the detection signal is a current value, the signal processing circuit 30 converts the detected current value into a voltage value, an amplifier that amplifies the detection signal, and an analog signal into a digital signal. It is composed of an A / D converter or the like.
Note that a configuration in which the filter control circuit 20 and the signal processing circuit 30 are provided in the optical module 10 may be employed.

[Configuration of control unit]
As shown in FIG. 1, the control unit 40 includes a storage unit 41 and a processing unit 42.
The storage unit 41 is configured by, for example, a memory or a hard disk drive. The storage unit 41 stores an OS (Operating System) for controlling the overall operation of the spectrometer 1, various programs, and various data.
And the memory | storage part 41 memorize | stores the V-lambda data etc. for driving the electrostatic actuator 56 of the wavelength variable interference filter 5 as said data. Here, in the present embodiment, the inclination angle θ is between the optical axis O of the wavelength variable interference filter 5 and the main optical axes L1 and L2 of each light (measurement light and reference light). Therefore, the relationship between the wavelength of transmitted light and the drive voltage to the electrostatic actuator 56 for transmitting the wavelength when the incident angle to the reflective films 54 and 55 is (90 ° −θ) is V−λ. It is preferably recorded in the data. Note that V-λ data when light is incident perpendicularly to the reflective films 54 and 55 is stored in the storage unit 41, and the processing unit 42 has an incident angle of (90 ° −) based on the V-λ data. A configuration may be used in which a driving voltage for a desired wavelength in the case of θ) is calculated.

  The processing unit 42 includes an arithmetic circuit such as a CPU (Central Processing Unit) and a storage circuit. As shown in FIG. 1, the processing unit 42 reads and executes various programs stored in the storage unit 41, and as shown in FIG. Functions as a measuring means).

The filter control unit 421 applies a voltage corresponding to the target wavelength to the electrostatic actuator 56 of the wavelength tunable interference filter 5 based on the V-λ data stored in the storage unit 41, and outputs the target wavelength from the wavelength tunable interference filter 5. Transmits light of wavelength.
The signal acquisition unit 422 acquires the detection signal input from the signal processing circuit 30.
The spectroscopic measurement unit 423 performs spectroscopic measurement of the measurement target X based on the acquired detection signal.

[Spectroscopic measurement method]
Next, a spectroscopic measurement method for the measurement target X by the spectroscopic measurement apparatus 1 as described above will be described with reference to the drawings.
FIG. 4 is a flowchart showing the spectroscopic measurement method of the present embodiment.
In the spectroscopic measurement method using the spectroscopic measurement apparatus 1 according to the present embodiment, first, the operator sets the measurement target X and performs an input operation for starting spectroscopic measurement on the spectroscopic measurement apparatus 1.
Accordingly, the filter control unit 421 drives the wavelength variable interference filter 5 to sequentially transmit light having a plurality of wavelengths in the measurement wavelength range from the wavelength variable interference filter 5. Further, the signal acquisition unit 422 acquires the amount of light of each wavelength (target measurement value S _Wλ and target reference value S _Rλ ) sequentially received by the light receiving unit 12 (step S10).

Specifically, the filter control means 421 reads the drive voltage for the target wavelength from the V-λ data stored in the storage unit 41 and filters the control signal indicating that the drive voltage is applied to the electrostatic actuator 56. Output to the circuit 20. As a result, a drive voltage is applied from the filter control circuit 20 to the electrostatic actuator 56, and the dimension of the gap G1 between the reflective films 54 and 55 of the wavelength variable interference filter 5 is changed. Further, the filter control means 421 sequentially changes the drive voltage applied to the electrostatic actuator 56 so that the light transmitted from the wavelength variable interference filter 5 becomes a predetermined interval (10 nm interval or the like), for example.
On the other hand, the signal acquisition unit 422 measures the measurement light received by the measurement light receiving element 121 every time the drive voltage is changed (every time the wavelength of the light transmitted from the wavelength variable interference filter 5 is switched). A value (target measurement value S _Wλ ), a measurement value (target reference value S _Rλ ) of the reference light received by the reference light receiving element 122 when the measurement light is received by the measurement light receiving element 121, and To get.

In this embodiment, as described above, the angle formed by the main optical axis L1 of the measurement light and the optical axis O of the wavelength variable interference filter 5, the main optical axis L2 of the reference light, and the optical axis of the wavelength variable interference filter 5 are as described above. Since the angles formed by O are the same inclination angle θ, the incident angles to the reflection films 54 and 55 are the same. Therefore, the wavelengths of the measurement light and the reference light that pass through the wavelength variable interference filter 5 are the same. That is, in this embodiment, the target measurement value S _Wλ and the target reference value S _Rλ for the same wavelength can be acquired simultaneously.

Thereafter, the spectroscopic measurement unit 423 calculates the reflectance R _λ for each wavelength by the following formula (1) based on the target measurement value S _Wλ for each wavelength and the target reference value S _Rλ acquired in step S10. (Step S11).

[Equation 1]
R _λ = S _Wλ / S _Rλ (1)

Further, the spectroscopic measurement unit 423 outputs the measurement result of the reflectance for each wavelength (spectral spectral characteristic of the measurement target X) calculated in step S11 to, for example, a display (not shown).
Thereafter, the processing unit 42 determines whether, for example, the operator continuously inputs that measurement is to be performed (step S12). If “Yes”, the processing unit 42 returns to step S10. If “No”, the spectroscopic measurement process is terminated.

[Operational effects of this embodiment]
In the present embodiment, the incident optical system 11 makes the measurement light incident at an inclination angle θ with respect to the optical axis O of the wavelength tunable interference filter 5 and causes the reference light to pass through the optical path different from the measurement light. The light is incident on the optical axis O at an inclination angle θ. The light receiving unit 12 individually receives the measurement light and the reference light transmitted through the wavelength variable interference filter 5. In such a configuration, the light quantity measurement of the reference light can be performed simultaneously with the measurement of the light quantity of the measurement light. Thereby, compared with the case where the light quantity measurement of the reference light is performed at a timing different from the measurement of the light quantity of the measurement light, the influence of the temporal change in the light quantity of the reference light can be suppressed.
Further, the main optical axis L1 of the measurement light and the main optical axis L2 of the reference light are inclined at the same inclination angle θ with respect to the optical axis O of the wavelength variable interference filter 5, and the incident angles to the reflection films 54 and 55 are It will be the same. Therefore, the wavelength of the measurement light that passes through the wavelength variable interference filter 5 and the wavelength of the reference light are the same.
As described above, in the present embodiment, the reflectance for each wavelength of the measurement target X can be calculated with high accuracy based on the reference light detected at the same wavelength and the same timing as the measurement light.

In the present embodiment, the light receiving unit 12 includes a measurement light receiving element 121 that receives measurement light, and a reference light receiving element 122 that receives reference light. As described above, the measurement light and the reference light transmitted through the wavelength tunable interference filter 5 are configured to be received by separate light receiving elements, so that inconvenience that one light is incident on the other light receiving element can be suppressed. The amount of light can be accurately detected. Further, since the light receiving element 121 for measurement light is arranged on the optical path of the measurement light and the light receiving element 122 for reference light is arranged on the optical path of the reference light, the optical for changing the optical path of the measurement light or the reference light A member can be made unnecessary, and reflection and absorption by these optical members can be suppressed, so that a decrease in light amount can be suppressed.
Also, the measurement light is received by the measurement light receiving element and the reference light is individually received by the reference light receiving element, so that the reference light is received by the measurement light receiving element or measured by the reference light receiving element. The inconvenience that light is received can be suppressed.

[Second Embodiment]
Next, 2nd embodiment which concerns on this invention is described based on drawing.
In the first embodiment, the plane including the optical axis O of the variable wavelength interference filter 5 and the main optical axis L1 of the measurement light and the plane including the optical axis O and the main optical axis L2 of the reference light are the same plane. showed that. On the other hand, the second embodiment is different from the first embodiment in that the plane including the optical axis O and the main optical axis L1 is different from the plane including the optical axis O and the main optical axis L2.

  FIG. 5A is a schematic view showing the optical module 10A of the second embodiment, and FIG. 5B shows the incident optical system 11A from the optical axis O of the wavelength variable interference filter 5 in FIG. It is a figure which shows the arrangement | positioning relationship of the measurement light incident optical system 111 and the reference light incident optical system 112 at the time of seeing. In addition, this embodiment adds the change to the optical module 10 in the spectrometer 1 of the first embodiment, and the filter control circuit 20, the signal processing circuit 30, and the control unit 40 are the same as those in the first embodiment. Since it is the same as that of FIG. In the following description, 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 optical module 10 </ b> A of the present embodiment, as shown in FIG. 5A, the measurement light incident optical system 111 emits the measurement light so as to have an inclination angle θ with respect to the optical axis O of the wavelength variable interference filter 5. Lead. Further, the reference light incident optical system 112 guides the reference light so as to have an inclination angle θ with respect to the optical axis O of the wavelength variable interference filter 5. Here, in this embodiment, a plane (measurement light plane P1) including the main optical axis L1 and the optical axis O of the measurement light, and a plane (reference light plane) including the main optical axis L2 and the optical axis O of the reference light. P2) is different from each other. More specifically, as shown in FIG. 5B, the measurement light plane P1 and the reference light plane P2 are orthogonal to each other, and the positions of the main optical axis L1 and the main optical axis L2 are along the optical axis O. It is asymmetric when viewed.

[Operational effects of this embodiment]
In the present embodiment, the measurement light plane P1 and the reference light plane P2 are different. For this reason, it is possible to suppress the disadvantage that the reference light is reflected by the wavelength variable interference filter 5 and enters the optical path of the measurement light to become a stray light component. Thereby, a more accurate spectroscopic measurement can be implemented.
Further, even if the measurement light plane P1 and the reference light plane P2 are different planes, the reference light may enter the optical path of the measurement light and irradiate the measurement target X if the angle formed thereby is small. On the other hand, in this embodiment, the incident optical system 11A is arranged so that the measurement light plane P1 and the reference light plane P2 are perpendicular to each other. Thereby, when the reference light is reflected by the variable wavelength interference filter 5, it is possible to further suppress the inconvenience of entering the optical path of the measurement light, and to suppress the decrease in measurement accuracy.

[Third embodiment]
Next, a third embodiment according to the present invention will be described based on the drawings.
The light receiving unit 12 of the first embodiment may perform, for example, one point of spectroscopic measurement processing of the measurement target X, and outputs a detection signal corresponding to the amount of received light as the light receiving element 121 for measurement light. If it is a light receiving element, it will not specifically limit. On the other hand, the spectroscopic measurement device 1 of the third embodiment acquires a spectroscopic image to be measured. That is, the third embodiment is different from the first embodiment in that an imaging element such as an image sensor is used as the light receiving element for measurement light.

FIG. 6 is a diagram showing a schematic configuration of the optical module according to the third embodiment of the present invention.
In the present embodiment, as shown in FIG. 6, the optical module 10B includes a wavelength variable interference filter 5, an incident optical system 11B, a wavelength variable interference filter 5, an imaging optical system 13, and a light receiving unit 12A. .
The light receiving unit 12A includes a measurement light receiving element 121A and a reference light receiving element 122.
An image sensor (imaging device) having a plurality of pixels (not shown) is used as the measurement light receiving element 121A. Examples of such an image sensor include a CCD (Charge Coupled Device) and a CMOS (Complementary MOS).
As the reference light receiving element 122, any photoelectric conversion element that outputs a signal corresponding to the amount of received light may be used, and an image sensor may be used in the same manner as the measurement light receiving element 121A.

The incident optical system 11B includes a measurement light incident optical system 111B, a reference light incident optical system 112B, and an incident light guide lens 113. The imaging optical system 13 includes a measurement light imaging optical system 131, a reference light imaging optical system 132, and an imaging light guide lens 133.
Here, the measurement light incident optical system 111B, the incident light guide lens 113, the imaging light guide lens 133, and the measurement light imaging optical system 131 constitute a telecentric optical system. That is, the measurement light incident optical system 111B and the incident light guide lens 113 make the principal rays of the measurement light parallel (or substantially parallel) before and after the wavelength variable interference filter 5, and the principal optical axis L1 of the measurement light is light. Measuring light is guided so as to have an inclination angle θ with respect to the axis O. Further, the imaging light guide lens 133 and the measurement light imaging optical system 131 guide the measurement light transmitted from the wavelength variable interference filter 5 to the measurement light receiving element 121A, and the measurement light is received by the measurement light receiving element 121A. Imaged.

The reference light incident optical system 112B is composed of a plurality of lens groups including a diffuser plate, and collects a wide range of illumination light such as external light and emits it to the incident light guide lens 113 side. The incident light guide lens 113 makes the principal ray of the reference light from the reference light incidence optical system 112B parallel (or substantially parallel), and the principal optical axis L2 of the reference light is the optical axis of the wavelength variable interference filter 5. The reference light is guided to the wavelength variable interference filter 5 so as to be inclined with respect to O at an inclination angle θ.
The imaging light guide lens 133 guides the reference light transmitted through the variable wavelength interference filter 5 toward the reference light receiving element 122, and the reference light imaging optical system 132 guides the reference light to the reference light receiving element. The image is formed on 122.

[Operational effects of this embodiment]
In the present embodiment, an image sensor having a plurality of pixels is used as the measurement light receiving element 121A. The measurement light incident optical system 111B, the incident light guide lens 113, the imaging light guide lens 133, and the measurement light imaging optical system 131 constitute a telecentric optical system. The principal ray is made parallel, and the principal optical axis L1 of the measurement light is inclined at an inclination angle θ with respect to the optical axis O of the wavelength variable interference filter 5, and then imaged on the measurement light receiving element 121A.
In such a configuration, it is possible to perform highly accurate spectroscopic measurement and acquire a spectroscopic image by the image sensor as in the above embodiment. That is, a highly accurate spectral image can be acquired.

[Fourth embodiment]
Next, 4th embodiment which concerns on this invention is described based on drawing.
In each of the above-described embodiments, the measurement light receiving elements 121 and 121A for receiving the measurement light and the reference light receiving element 122 for receiving the reference light are provided as separate bodies. In contrast, the present embodiment is different from the above embodiments in that the measurement light and the reference light are received by one light receiving element.

FIG. 7 is a diagram illustrating a schematic configuration of the optical module according to the fourth embodiment.
The optical module 10C of the present embodiment includes the variable wavelength interference filter 5, the incident optical system 11B and the imaging optical system 13 similar to those of the third embodiment, and the light receiving unit 12B.
As illustrated in FIG. 7, the light receiving unit 12 </ b> B includes a single image sensor (image sensor) including a plurality of pixels. The light receiving unit 12B includes a measurement pixel region 12B1 in which measurement light is received and a reference pixel region 12B2 in which reference light is received among a plurality of pixels.

Here, in this embodiment, when the signal acquisition unit 422 of the control unit 40 acquires the image signal from the light receiving unit 12B, the measurement pixel region 12B1 and the reference pixel region 12B2 are specified from each pixel of the image signal. Then, the signal value of each pixel in the specified measurement pixel region 12B1 is acquired as the measurement value, and the signal value of each pixel in the reference pixel region 12B2 is acquired as the reference value.
That is, in the present embodiment, the positions of the measurement pixel region 12B1 and the reference pixel region 12B2 in the light receiving unit 12B are regions determined by the arrangement of the incident optical system 11B and the imaging optical system 13. Therefore, the signal acquisition unit 422 can easily acquire the respective light amounts by separating the measurement light and the reference light by acquiring the signal value of each pixel in the region.

[Operational effects of this embodiment]
In the present embodiment, the measurement light and the reference light transmitted through the wavelength variable interference filter 5 are received by the light receiving unit 12B that is one image sensor, and the measurement pixel region 12B1 in which the measurement light is received by the light receiving unit 12B; A reference pixel region 12B2 that receives the reference light is provided.
For example, when two light receiving elements, ie, a light receiving element for measurement light and a light receiving element for reference light are used, if the light receiving sensitivity characteristics thereof are different, the light amount measurement of illumination light (detected as reference light) irradiated to the measurement object X is performed. It is conceivable that an error will occur and the measurement accuracy will deteriorate. On the other hand, according to the above configuration, in the present embodiment, since the measurement light and the reference light are received by the same light receiving element, an error in light amount measurement due to a difference in light reception sensitivity does not occur, and the measurement accuracy can be improved. .

[Fifth embodiment]
Next, a fifth embodiment according to the present invention will be described with reference to the drawings.
In the first embodiment, the reference light received at the same time as the measurement light is set to the same amount of light as the illumination light irradiated to the measurement target X, and the reflectance of the measurement target X is calculated using equation (1). .
On the other hand, in the fifth embodiment, the primary reference data is acquired by spectroscopic measurement with respect to a standard white plate (standard white object), and the reflectance of the measurement light is calculated based on the primary reference data. It is different from the first embodiment.

FIG. 8 is a diagram showing a schematic configuration of a spectroscopic measurement apparatus 1A of the fifth embodiment.
In the spectroscopic measurement apparatus 1A of the present embodiment, as shown in FIG. 8, the processing unit 42 in the control unit 40 further functions as a mode setting unit 424. The signal acquisition unit 422 of the present embodiment functions as a reference value acquisition unit and a target value acquisition unit of the present invention.
The mode setting unit 424 switches between the reference mode and the measurement mode. Here, the reference mode uses a standard white object (such as a white plate) in which the reflectance of each wavelength in a predetermined measurement wavelength region is, for example, 99 to 100% instead of the measurement object X, and a reference value for reference Is a mode for measuring. The measurement mode is a mode for performing spectroscopic measurement of the measurement target X.

[Spectral Measurement Processing of Spectrometer 1A]
Next, a spectroscopic measurement method of the spectroscopic measurement apparatus 1A of the present embodiment will be described based on the drawings.
FIG. 9 is a flowchart showing the spectroscopic measurement process of the present embodiment.
In the present embodiment, primary reference data is acquired prior to step S10 shown in FIG.
That is, in the present embodiment, the operator sets a standard white plate as a measurement object, and inputs an instruction for instructing acquisition processing of primary reference data to the spectroscopic measurement apparatus 1A. Thereby, the mode setting means 424 switches the operation mode to the reference mode (step S1).

In the reference mode, when the operator inputs a spectroscopic measurement start instruction to the spectroscopic measurement apparatus 1A, the filter control unit 421 drives the wavelength variable interference filter 5 to measure the measurement wavelength as in step S10 in FIG. A plurality of wavelengths of light in the region are sequentially transmitted from the wavelength variable interference filter 5. Further, the signal acquisition unit 422 acquires the amount of light of each wavelength of the measurement light and the reference light sequentially received by the light receiving unit 12 as in Step S10 of FIG. 4 (Step S2).
The amount of measurement light (standard measurement value S _Wλ−Ref ) and the amount of reference light (standard reference value S _Rλ−Ref ) acquired in step S ₂ are stored in the storage unit 41.

Next, when it is input by the operator's operation that the spectroscopic measurement of the measurement target X is performed, the mode setting unit 424 of the processing unit 42 switches the operation mode to the measurement mode (step S3).
Then, the same processing as step S10 in FIG. 4 is performed to _obtain the target measurement value S _Wλ and the target reference value S _Rλ of each wavelength for the measurement target X.

Thereafter, the spectroscopic measurement unit 423 calculates the reflectance R for each wavelength according to the following equation (2) based on the target measurement value S _Wλ and the target reference value S _Rλ for each wavelength acquired in Step S2 and Step S10. _λ is calculated (step S4).

[Equation 2]
R _λ = S _Wλ / S _Wλ−Ref × S _Rλ−Ref / S _Rλ (2)

Further, the spectroscopic measurement unit 423 outputs the measurement result of the reflectance for each wavelength (spectral spectral characteristic of the measurement target X) calculated in step S4 to, for example, a display (not shown).
Thereafter, step S12 is performed as in the first embodiment.

If each of the light receiving elements 121 and 122 is dark, the darkness of each of the light receiving elements 121 and 122 is first detected in the light shielding space, and the reflectivity R _λ taking dark into account is obtained by the following equation (3). Calculation may be performed. In this case, the reflectance can be calculated with higher accuracy. In equation (3), D _Wλ is the _darkness of the light receiving element 121 for measurement light at the wavelength λ, and D _Rλ is the darkness of the light receiving element 122 for reference light at the wavelength λ.

[Equation 3]
_{R λ = (S Wλ -D Wλ} ) / (S Wλ-Ref -D Wλ) × (S Rλ-Ref -D Rλ) / (S Rλ -D Rλ) ... (3)

[Operational effects of this embodiment]
In the present embodiment, primary reference data (standard measurement value S _Wλ-Ref , standard reference value S _Rλ-Ref ) using a standard white plate and measurement data for the measurement target X (target measurement value S _Wλ , target reference value). S _Rλ ) is used to calculate the reflectance of the measurement object X. Thereby, even when there is a light amount difference between the illumination light irradiated from the light source 2 to the measurement object X and the reference light directly incident on the optical module 10 from the light source 2, the accuracy of suppressing the influence of the light amount difference High spectroscopic measurement can be performed. That is, the relative position between the optical module 10 and the measurement target X when the measurement target X is measured and the relative position between the optical module 10 and the standard white plate when acquiring the primary reference data are the same. By making it, measurement conditions can be made the same. In this case, the amount of illumination light may differ between when primary reference data is acquired and when measurement data of a measurement target X is acquired. In this embodiment, as shown in equation (2), reference reference is used. Using the value S _Rλ-Ref and the target reference value S _Rλ , correction is performed so that the light intensity condition of the illumination light irradiated on the measurement target X or the standard white plate is the same. Thereby, the spectroscopic measurement which suppressed the influence by the time-dependent change of the illumination light from the light source 2 can be performed.

[Modification of Embodiment]
Note that the present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifying, improving, and appropriately combining the embodiments as long as the object of the present invention can be achieved. Is.

For example, in each of the above embodiments, the reflectance R _λ of the measurement target X is measured based on the measurement data. However, the wavelength measurement of the spectrometers 1 and 1A may be performed based on the measurement data. For example, implementing the spectral measurement on the reference object reflectivity are known, (1) using the formula and (2), measuring the reflectivity R _lambda of each wavelength. Then, the known reflectance of the reference object stored in advance and the calculated reflectance R _λ are compared to determine the wavelength shift, and wavelength calibration is performed in the spectrometers 1 and 1A. As described above, the spectroscopic measurement apparatuses 1 and 1A can obtain the reference value of the reference light simultaneously with the measurement value of the measurement light, and thus can calculate the reflectance R _λ with high accuracy. Accordingly, it is possible to highly determine the coincidence between the calculated reflectance R _λ and the known reflectance of the reference object. Thereby, when a wavelength shift occurs, the shift amount can be calculated with high accuracy, and appropriate wavelength calibration can be performed.

  In the first and second embodiments, when a spectral image is not acquired and, for example, one point in the measurement target X is used as a measurement site, a collimator lens that converts the measurement light into parallel light is used in the measurement light incident optical system 111. May be. Thereby, compared with the case where a telecentric optical system etc. are used, the number of parts of optical members, such as a lens, can be reduced, and a structure can be simplified.

  As the second embodiment, the main optical axis L1 of the measurement light and the main optical axis L2 of the reference light are asymmetric with respect to the optical axis O with respect to the optical module 10 in the spectrometer 1 of the first embodiment. As described above, the example in which the positions of the measurement light incident optical system 111 and the reference light incident optical system 112 are set has been described. Similarly, the optical modules 10, 10B, and 10C of the third and fourth embodiments are also described. The positional relationship between the measurement light incident optical system 111B and the reference light incident optical system 112B is set so that the main optical axis L1 of the measurement light and the main optical axis L2 of the reference light are asymmetric with respect to the optical axis O. It may be set.

In the fifth embodiment, the example in which the reflectance R _λ is calculated using the equations (2) and (3) with respect to the configuration of the first embodiment has been described. However, similarly, after performing the acquisition process of the primary reference data using the standard white plate, the reflectance R of the measurement target X using the primary reference data and the equations (2) and (3). _λ may be calculated.

In each of the above embodiments, the wavelength variable interference filter 5 that can change the size of the gap G1 between the reflection films 54 and 55 by changing the voltage to the electrostatic actuator 56 is exemplified as the interference filter. It is not limited to. For example, an interference filter in which the gap dimension between the pair of reflective films is fixed may be used.
Further, although the transmissive variable wavelength interference filter 5 that transmits light having a wavelength corresponding to the size of the gap G1 between the reflective films 54 and 55 is illustrated, a reflective wavelength that reflects light having a wavelength corresponding to the gap G1. A variable interference filter 5 may be used.

  In addition, the specific structure for carrying out the present invention may be configured by appropriately combining the above-described embodiments and modifications within the scope that can achieve the object of the present invention, and may be appropriately changed to other structures and the like. May be.

  DESCRIPTION OF SYMBOLS 1,1A ... Spectrometer, 2 ... Light source, 5 ... Variable wavelength interference filter 10, 10A, 10B, 10C ... Optical module, 11, 11A, 11B ... Incident optical system, 12, 12B ... Light receiving part, 12B1 ... Measurement Pixel area, 12B2 ... reference pixel area, 13 ... imaging optical system, 40 ... control section, 41 ... storage section, 42 ... processing section, 54 ... fixed reflection film, 55 ... movable reflection film, 56 ... electrostatic actuator, 111 111B ... Measurement light incident optical system, 112,112B ... Reference light incident optical system, 121,121A ... Measurement light receiving element, 122 ... Reference light receiving element, 131 ... Measurement light imaging optical system, 132 ... Reference light Imaging optical system, 133 ... Imaging light guide lens, 421 ... Filter control means, 422 ... Signal acquisition means, 423 ... Spectroscopic measurement means, 424 ... Mode setting means, G1 ... Gap, L1 ... Measurement The main optical axis of the light, the main optical axis of L2 ... reference light, O ... optical axis, P1 ... measurement light plane, P2 ... reference light plane, X ... measured, theta ... tilt angle.

Claims (7)

An interference filter that has a pair of reflective films opposed to each other, and emits light having a wavelength according to a gap dimension between the reflective films from light incident on the pair of reflective films;
An incident optical system that guides the measurement light reflected by the measurement object with the illumination light applied to the measurement object, and the reference light that is the illumination light that does not pass through the measurement object to the interference filter in separate optical paths, and
A light receiving unit for receiving the measurement light and the reference light emitted from the interference filter,
The incident optical system is configured such that the main optical axis of the measurement light is inclined by a predetermined angle with respect to the optical axis of the interference filter and is incident on the interference filter, and the main optical axis of the reference light is set to the optical axis of the interference filter. The spectroscopic measurement device, wherein the spectroscopic measurement device is inclined with respect to the predetermined angle to enter the interference filter. The spectroscopic measurement device according to claim 1,
The spectroscopic measurement apparatus, wherein a plane including the optical axis of the interference filter and a main optical axis of the measurement light is different from a plane including the optical axis of the interference filter and the main optical axis of the reference light. The spectroscopic measurement device according to claim 1 or 2,
The spectroscopic measurement apparatus, wherein the light receiving unit includes a measurement light receiving element that receives the measurement light and a reference light receiving element that receives the reference light. The spectrometer according to claim 3,
The light receiving element for measurement light has a plurality of pixels, and is an image pickup element that picks up an image of the measurement light output from the interference filter,
A spectroscopic measurement apparatus, wherein an imaging optical system for forming an image on the image sensor is provided on the optical path of the measurement light. The spectroscopic measurement device according to claim 1 or 2,
The light receiving unit is an imaging device having a plurality of pixels, and includes a measurement pixel region for detecting the measurement light and a reference pixel region for detecting the reference light. In the spectroscopic measurement device according to any one of claims 1 to 5,
The reference measurement light reflected by the standard white object is received and output by the light receiving unit, and the reference light is received by the light receiving unit and output when the standard measurement value is output. A reference value acquisition means for acquiring a reference reference value;
The measurement light reflected by the measurement object is received and output by the light receiving unit, and the reference light is received by the light receiving unit and output when the target measurement value is output. Target value acquisition means for acquiring a target reference value;
Reflectance measurement means for calculating the reflectance of each wavelength of the measurement target using the standard measurement value, the reference reference value, the target measurement value, and the target reference value;
A spectroscopic measurement device comprising: An interference filter that has a pair of reflective films facing each other and emits light having a wavelength according to a gap dimension between the reflective films from light incident on the pair of reflective films, and illumination light irradiated to the measurement target Are incident optical systems that guide the measurement light reflected by the measurement object and the reference light that is the illumination light that does not pass through the measurement object to the interference filter in separate optical paths, and the light emitted from the interference filter A light receiving section for receiving each of the measurement light and the reference light, and the incident optical system is incident on the interference filter with a main optical axis of the measurement light inclined at a predetermined angle with respect to an optical axis of the interference filter. And a spectroscopic measurement method in a spectroscopic measurement apparatus in which the main optical axis of the reference light is inclined at the predetermined angle with respect to the optical axis of the interference filter and is incident on the interference filter.
The reference measurement light reflected by the standard white object is received and output by the light receiving unit, and the reference light is received by the light receiving unit and output when the standard measurement value is output. Get the standard reference value,
The measurement light reflected by the measurement object is received and output by the light receiving unit, and the reference light is received by the light receiving unit and output when the target measurement value is output. Get the target reference value,
The reflectance of each wavelength of the measurement object is calculated using the standard measurement value, the standard reference value, the target measurement value, and the target reference value.

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