JP6142479B2 - Spectrometer - Google Patents

Description

  The present invention relates to an electronic device.

2. Description of the Related Art Conventionally, a spectroscopic measurement apparatus that emits light from a light source, makes light reflected by a measurement target incident on a spectroscopic element, and detects the light extracted by the spectroscopic element is known (see, for example, Patent Document 1).
The spectroscopic measurement apparatus described in Patent Document 1 employs a configuration in which a measurement object is illuminated with a white light source and a monochrome image obtained through a tunable filter is captured by an image sensor.

JP 2001-228024 A

By the way, in recent years, a small and portable device is desired as a spectroscopic measurement device. However, in an apparatus using a tunable filter as described in Patent Document 1, the configuration is complicated and it is difficult to cope with downsizing. Further, the driving power for driving the tunable filter is large, and there is a problem that it is difficult to save power corresponding to the portable device.
Furthermore, when a white light source is irradiated onto a measurement object as in the apparatus described in Patent Document 1, light in an unnecessary wavelength region that is not used as a spectral image is emitted from the light source. In such a configuration that emits light in an unnecessary wavelength range from the light source, it is not possible to achieve power saving of the light source. As a result, it becomes difficult to save power of the apparatus, and in particular, a portable type in which the power supply amount is limited. There is a problem that it is not suitable for a small device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic device that can reduce power consumption by turning on only a light source in a necessary wavelength range and can be miniaturized.

One aspect of the present invention includes a wavelength tunable interference filter that includes a plurality of light sources, two reflective films that face each other through a gap, and a gap changing unit that changes the gap, and that extracts light of a predetermined wavelength, and a control unit Each of the plurality of light sources has a different emission wavelength range, and the control unit emits light in the emission wavelength range corresponding to the wavelength of the light extracted by the variable wavelength interference filter among the plurality of light sources. A light source control means for turning on an emitted light source and turning off the other light sources; and a filter control means for controlling the gap changing section to change the wavelength of light taken out by the variable wavelength interference filter. The control unit is configured to perform the second wave in the subsequent measurement after the filter control unit sets the gap to the first gap and extracts the light having the first wavelength. The first light source among the plurality of light sources that has been turned off is turned on until the gap is changed to the second gap in order to take out the light, and when the measurement is not performed, The second light source that has been turned on is turned off.
The electronic apparatus according to the present invention includes a plurality of light sources, two reflective films facing each other through a gap, and a gap changing unit that changes the gap, and the two reflective films emit light having a predetermined wavelength. A variable wavelength interference filter to be extracted; and a control unit, wherein each of the plurality of light sources has a different emission wavelength range, and the control unit is configured to select a wavelength of light to be extracted by the variable wavelength interference filter from the plurality of light sources. A light source control means for turning on a light source that emits light in a light emission wavelength range corresponding to the above and turning off the other light sources, and a filter for changing the wavelength of light taken out by the wavelength variable interference filter by controlling the gap changing unit And the light source control means, after the filter control means sets the gap as the first gap and takes out light of the first wavelength. In the subsequent measurement, the light source is switched on and off until the gap is changed to the second gap in order to extract the light of the second wavelength and when the measurement is not performed. It is characterized by.
An electronic apparatus according to the present invention includes a plurality of light sources having different wavelength ranges to emit light, two reflective films facing each other through a predetermined gap, and a gap changing unit that changes the gap. A wavelength tunable interference filter that extracts light having a wavelength of λ, and a control unit, wherein the control unit emits light in a light emission wavelength range corresponding to the wavelength of light extracted by the wavelength tunable interference filter among the plurality of light sources. A light source control means for turning on an emitted light source and turning off the other light sources; and a filter control means for controlling the gap changing section to change the wavelength of light extracted by the wavelength variable interference filter. The control means performs measurement after the filter control means sets the gap to the first gap and takes out the light of the first wavelength. Between the gaps in order to take out light of the second wavelength to be changed to the second gap, when not and the measurement, and switches the lighting and extinguishing of the light source.

In the present invention, the electronic device is provided with a variable wavelength interference filter having reflection films facing each other with a gap between the reflection films. Such a wavelength tunable interference filter can be configured by, for example, opposingly arranging the substrates on which the respective reflection films are formed, and compared with the case where other tunable filters (for example, LCTF, AOTF, etc.) are used. The configuration can be simplified and the apparatus can be miniaturized.
In the present invention, a plurality of light sources having different emission wavelength ranges are provided, and the light source control means turns on a light source that emits light of a target wavelength extracted by the variable wavelength interference filter, and turns off the other light sources. For this reason, compared with the case where white light sources, such as a halogen lamp, are used, the light of an unnecessary wavelength range can be cut, and the power consumption concerning a light source drive can be suppressed by that much. As a result, power saving can be achieved even in a portable device with limited supply power.
Therefore, according to the present invention, an electronic device with low power consumption and capable of being downsized can be provided.

On the other hand, if the light source is switched according to the wavelength of the light to be extracted, it is conceivable that a delay occurs when the light source is switched or a delay occurs until stable light is emitted from the switched light source. In the wavelength tunable interference filter, after changing the gap between the reflection films, the gap between the reflection films disappears, and it waits for a time until the light of the target wavelength is stably extracted (wavelength stabilization time). There is a need to. Therefore, it can be considered that the time required for various processes in the electronic device becomes longer due to the delay time and the wavelength stabilization time for driving these light sources. For example, when an electronic device reflects light from a light source to a measurement target and takes out light of a predetermined wavelength from the reflected light with a wavelength variable interference filter to perform spectroscopic measurement, stable driving of the light source, wavelength variable interference filter It takes time for both stable driving. Similarly, in an illumination device that selects and outputs a desired wavelength from the light emitted from the light source using the wavelength variable interference filter, it takes time for both the stable driving of the light source and the stable driving of the wavelength variable interference filter. .
In contrast, in the present invention, when the gap between the reflection films in the wavelength tunable interference filter is changed, a process of switching the light source to be lit is performed. That is, the light source is switched during the wavelength stabilization time so that stable light is emitted from the light source. Thereby, a delay required for switching the light source and a time delay until stable light is emitted from the light source can be included in the wavelength stabilization time, and various processes in the electronic device can be performed quickly.

In the electronic apparatus according to the present invention, it is preferable that the electronic apparatus includes a light receiving unit that receives light extracted by the wavelength variable interference filter.
In the present invention, the light extracted by the wavelength variable interference filter is received by the light receiving unit, and the amount of the received light is measured. Thereby, the light quantity of the light transmitted from the wavelength variable interference filter can be measured, and a spectral image corresponding to the transmitted wavelength can be acquired.

In the electronic device of the present invention, it is preferable that the light emission intensities of the plurality of light sources are set so as to obtain a uniform light intensity at each wavelength based on the filter characteristics of the wavelength variable interference filter.
The variable wavelength interference filter has different filter characteristics (transmittance and reflectance) for each wavelength. Therefore, there is a case where light having a wavelength with a small transmittance of the wavelength tunable interference filter cannot be accurately processed as various processes in the electronic apparatus. For example, when using an illuminating device that extracts and emits light of a desired wavelength from light emitted from a light source as an electronic device, the light intensity is sufficient at a wavelength where the transmittance of the wavelength interference filter is low. The light cannot be emitted.
On the other hand, in the present invention, the light emission intensity of each light source is individually set so that light can be extracted from the wavelength variable interference filter with a sufficient amount of light even for wavelengths with low filter characteristics of the wavelength variable interference filter. Is set to Thereby, various highly accurate processes in the electronic device can be performed.

In the electronic device of the present invention, the light emission intensity of the light source is set so that uniform light intensity can be obtained at each wavelength based on the light reception characteristic of the light receiving unit and the filter characteristic of the wavelength variable interference filter. It is preferable.
In this invention, the light-receiving part which receives the light taken out by the wavelength variable interference filter is provided. Since such a light receiving unit has different light receiving characteristics (light receiving sensitivity characteristics) for each wavelength, simply changing the light emission intensity of each light source according to the filter characteristics of the wavelength variable interference filter as described above. In the wavelength where the sensitivity characteristic of the light receiving portion is low, the amount of received light cannot be sufficiently obtained. In this case, high-precision processing cannot be performed when various processing such as spectroscopic measurement is performed based on the amount of light received by the light-receiving unit.
On the other hand, in the present invention, the light emission intensity of each light source is set based on the light reception characteristics of the light receiving unit in addition to the filter characteristics of the wavelength variable interference filter. Therefore, even if the light receiving sensitivity of the light receiving unit is low or the wavelength of the wavelength variable interference filter is low, the light emission intensity of the light source is set to be large so that a sufficient amount of light can be detected in the light receiving unit. Thus, various highly accurate processes can be performed.

In the electronic apparatus according to the aspect of the invention, it is preferable that the light source control unit drives the light source so that uniform light intensity can be obtained at each wavelength based on the filter characteristics of the wavelength variable interference filter.
In the above-described invention, the light emission intensity of each light source is different when the light source is driven with a predetermined drive voltage. However, in the present invention, the drive voltage for driving each light source by the light source control means is variable in wavelength. Different according to the filter characteristics of the interference filter. Even in this case, light having a target wavelength can be extracted with a sufficient amount of light even with respect to a wavelength having a low filter characteristic of the variable wavelength interference filter.
Moreover, even when the emission intensity for each wavelength in the predetermined emission wavelength range varies, the desired emission intensity can be obtained by controlling the drive voltage applied to the light source.

The electronic apparatus of the present invention includes a light receiving unit that receives light extracted by the wavelength tunable interference filter, and the light source control unit is based on a light receiving characteristic of the light receiving unit and a filter characteristic of the wavelength tunable interference filter. Thus, it is preferable to drive the light source so that uniform light intensity is obtained at each wavelength.
In this invention, the light-receiving part which receives the light taken out by the wavelength variable interference filter is provided. Since such a light receiving unit has different light receiving characteristics (light receiving sensitivity) for each wavelength, as described above, only by changing the light emission intensity of each light source according to the filter characteristics of the wavelength variable interference filter, A sufficient amount of received light cannot be obtained at a wavelength where the sensitivity characteristic of the light receiving part is low. In this case, high-precision processing cannot be performed when various processing such as spectroscopic measurement is performed based on the amount of light received by the light-receiving unit.
On the other hand, in the present invention, the light emission intensity of the light source is adjusted by the light source control means based on the light receiving sensitivity of the light receiving unit in addition to the filter characteristics of the wavelength variable interference filter. Therefore, it becomes possible to detect a sufficient amount of light even for a wavelength having a low light receiving sensitivity of the light receiving unit, so that highly accurate processing can be performed.

Schematic which shows the structure of the spectroscopic camera (electronic device) of 1st embodiment which concerns on this invention. The top view which shows schematic structure of the wavelength variable interference filter of 1st embodiment. Sectional drawing of the wavelength variable interference filter when the III-III line of FIG. 2 is cut. The figure which shows the filter characteristic (transmittance characteristic) of the wavelength variable interference filter of 1st embodiment. The figure which shows the light reception characteristic (sensitivity characteristic) of the imaging part of 1st embodiment. The figure which shows the example of arrangement | positioning of the light source which comprises the light source part of 1st embodiment. The figure which shows the positional relationship of each light source in 1st embodiment, an imaging part, and a wavelength variable interference filter. The figure which shows the spectral spectrum (light emission intensity characteristic) of the illumination light inject | emitted from each light source of 1st embodiment. The figure which piled up the emission intensity characteristic of the light source of 1st embodiment, the transmittance | permeability characteristic of a wavelength variable interference filter, and the sensitivity characteristic of an imaging part. The figure which shows the optical characteristic of the near-infrared imaging module which multiplied the light emission intensity characteristic of the light source of 1st embodiment, the transmittance | permeability characteristic of a wavelength variable interference filter, and the sensitivity characteristic of an imaging part. The block diagram which shows schematic structure of the spectroscopic camera of 1st embodiment. The flowchart which shows the spectral image acquisition process of the spectral camera of 1st embodiment. The timing chart in the spectral image acquisition process of 1st embodiment. The block diagram which shows schematic structure of the illuminating device (electronic device) of 3rd embodiment. The flowchart of the illumination process in 3rd embodiment.

[First embodiment]
Hereinafter, a spectral camera (electronic device) according to a first embodiment of the present invention will be described with reference to the drawings.
[Schematic configuration of spectroscopic camera]
FIG. 1 is a schematic view showing the spectroscopic camera of the first embodiment.
The spectroscopic camera 10 is an electronic apparatus of the present invention, and is a device that captures a spectroscopic image of the measurement target X.
As shown in FIG. 1, the spectroscopic camera 10 includes a housing 11, a visible light imaging module 12, a near infrared imaging module 13, a display 15, an operation unit 16, and a control unit 17. Yes.

[Configuration of casing 11]
The case 11 has a thickness of about 1 to 2 cm, for example, and is formed in a thin box shape that can be easily stored in a pocket of clothes. As shown in FIG. 1, the housing 11 faces the front surface 11 </ b> A, a visible imaging window 111 in which the visible light imaging module 12 is disposed, and a near infrared imaging window in which the near infrared imaging module 13 is disposed. 112 is provided. Moreover, the housing | casing 11 is provided with the display window 114 where the display 15 is arrange | positioned facing the back surface 11B, as shown in FIG. Further, the housing 11 includes a shutter button (not shown) for capturing a captured image by the visible light imaging module 12 or the near infrared imaging module 13 in a part of the side surface 11C.

[Configuration of Visible Light Imaging Module 12]
The visible light imaging module 12 includes a visible light incident unit 121 (color image incident optical system) provided facing the visible imaging window 111 of the housing 11 and a color imaging unit 122.
1 shows an example in which the visible light incident unit 121 is configured by a single lens, but actually, the visible light incident unit 121 is configured by a plurality of lenses, and a virtual image of the inspection object is color-captured by these lenses. The image is formed on the portion 122.
The color imaging unit 122 includes a plurality of imaging elements. Each of these image sensors includes, for example, an R (red) image sensor, a G (green) image sensor, and a B (blue) image sensor per pixel, and each color corresponds to the color of light received. It has filters (R, G, B).
Then, the color imaging unit 122 outputs a color image signal based on the light received by each imaging element to the control unit 17.

[Configuration of Near-Infrared Imaging Module 13]
The near-infrared imaging module 13 receives light from a light incident part 131 provided facing the near-infrared imaging window 112, a light source part 132 provided facing the near-infrared imaging window 112, and light from the light incident part 131. The variable wavelength interference filter 5 is configured to include an imaging unit 133 (light receiving unit) that receives the light extracted by the variable wavelength interference filter 5, and a control board 134.

(Configuration of light incident portion 131)
As shown in FIG. 1, the light incident part 131 includes a plurality of lenses. The light incident unit 131 has a viewing angle limited to a predetermined angle or less by the plurality of lenses, and connects a virtual image of the inspection object within the viewing angle to the imaging unit 133 via the wavelength variable interference filter 5. Image. In addition, a part of the plurality of lenses can adjust the lens interval, for example, when the operation unit 16 is operated by the user, and thus the acquired image can be enlarged or reduced. . In this embodiment, it is preferable to use a telecentric lens as these lenses constituting the light incident part 131.

(Configuration of wavelength variable interference filter 5)
FIG. 2 is a plan view showing a schematic configuration of the variable wavelength interference filter 5. FIG. 3 is a cross-sectional view of the wavelength tunable interference filter 5 taken along the line III-III in FIG.
The wavelength variable interference filter 5 is a Fabry-Perot etalon. The wavelength variable interference filter 5 is, for example, a rectangular plate-like optical member, and includes a fixed substrate 51 having a thickness dimension of, for example, about 500 μm and a movable substrate 52 having a thickness dimension of, for example, about 200 μm. . The fixed substrate 51 and the movable substrate 52 are each formed of, for example, various types of glass such as soda glass, crystalline glass, quartz glass, lead glass, potassium glass, borosilicate glass, and non-alkali glass, or crystal. . The fixed substrate 51 and the movable substrate 52 are bonded such that the first bonding portion 513 of the fixed substrate 51 and the second bonding portion 523 of the movable substrate 52 are made of, for example, a plasma polymerization film mainly containing siloxane. By being bonded by the film 53 (the first bonding film 531 and the second bonding film 532), they are integrally formed.

The fixed substrate 51 is provided with a fixed reflective film 54, and the movable substrate 52 is provided with a movable reflective film 55. 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 used to adjust (change) the gap amount of the inter-reflection film gap G1. 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. These fixed electrode 561 and movable electrode 562 are opposed to each other through an interelectrode gap G2. Here, the fixed electrode 561 and the movable electrode 562 may be provided directly on the surface of the fixed substrate 51 and the movable substrate 52, respectively, or may be provided via other film members. Good. Here, the gap amount of the inter-electrode gap G2 is larger than the gap amount of the inter-reflection film gap G1.
Further, in the filter plan view as shown in FIG. 2 in which the wavelength variable interference filter 5 is viewed from the thickness direction of the fixed substrate 51 (movable substrate 52), the plane center point O of the fixed substrate 51 and the movable substrate 52 is fixed reflection. It coincides with the center point of the film 54 and the movable reflective film 55 and coincides with the center point of the movable part 521 described later.
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.

(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.
Further, a notch 514 is formed at the apex C1 of the fixed substrate 51, and a movable electrode pad 564P described later is exposed on the fixed substrate 51 side of the wavelength variable interference filter 5.

The electrode arrangement groove 511 is formed in an annular shape centering on the plane center point O 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.
In addition, the fixed substrate 51 is provided with electrode extraction grooves 511B extending from the electrode arrangement grooves 511 toward the vertexes C1 and C2 of the outer peripheral edge of the fixed substrate 51.

A fixed electrode 561 is provided on the electrode installation surface 511 </ b> A of the electrode arrangement groove 511. More specifically, 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 extending from the outer peripheral edge of the fixed electrode 561 in the direction of the vertex C2. The extended leading end portion (portion located at the vertex C2 of the fixed substrate 51) of the fixed extraction electrode 563 constitutes a fixed electrode pad 563P connected to the control substrate 134.
In the present embodiment, a configuration in which one fixed electrode 561 is provided on the electrode installation surface 511A is shown. For example, a configuration in which two concentric circles centered on the plane center point O are provided (double electrode configuration). ) Etc.

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. Furthermore, 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-layer 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 surface of the fixed substrate 51 that faces the movable substrate 52, the surface on which the electrode placement groove 511, the reflective film installation portion 512, and the electrode extraction groove 511B are not formed by etching constitutes the first joint 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 has a circular movable portion 521 centered on the plane center point O in the filter plan view as shown in FIG. 2, a holding portion 522 that is coaxial with the movable portion 521 and holds the movable portion 521, A substrate outer peripheral portion 525 provided outside the holding portion 522.
Further, as shown in FIG. 2, the movable substrate 52 has a notch 524 corresponding to the vertex C <b> 2, and the fixed electrode pad when the wavelength variable interference filter 5 is viewed from the movable substrate 52 side. 563P is exposed.

The movable part 521 is formed to have a thickness dimension larger than that of the holding part 522. For example, in this embodiment, the movable part 521 is formed to have the same dimension as the thickness dimension of the movable substrate 52. 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 through the inter-electrode gap G2, and is formed in an annular shape having the same shape as the fixed electrode 561. In addition, the movable substrate 52 includes a movable extraction electrode 564 that extends from the outer peripheral edge of the movable electrode 562 toward the vertex C <b> 1 of the movable substrate 52. An extending tip portion of the movable extraction electrode 564 (portion located at the vertex C1 of the movable substrate 52) constitutes a movable electrode pad 564P connected to the control substrate 134.
The movable reflective film 55 is provided at the center of the movable surface 521A of the movable part 521 so as to face the fixed reflective film 54 with the gap G1 between the reflective films. 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 gap amount of the interelectrode gap G2 is larger than the gap amount 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 as the measurement target light, the gap amount of the reflection film gap G1 may be larger than the gap amount of the interelectrode gap G2 depending on the wavelength range of the measurement target light.

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 this embodiment, the diaphragm-like holding part 522 is illustrated, but the present invention is not limited to this. For example, a configuration in which beam-like holding parts arranged at equiangular intervals around the plane center point O are provided. And so on.

  As described above, the substrate outer peripheral portion 525 is provided outside the holding portion 522 in the filter plan view. The surface of the substrate outer peripheral portion 525 that faces the fixed substrate 51 includes a second joint portion 523 that faces the first joint portion 513. 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. Are joined.

(Size and arrangement position of the wavelength variable interference filter 5)
In the spectral camera 10 of the present embodiment, the color image is captured by the visible light imaging module 12. Therefore, the variable wavelength interference filter 5 only needs to be formed to a size that can transmit light in the near infrared region. Therefore, the near-infrared light can be extracted as the primary peak wavelength or the secondary peak wavelength by setting the gap G1 between the reflection films to 1 μm or less, for example. Further, as described above, the thickness dimension of the fixed substrate 51 is, for example, about 500 μm, and the thickness dimension of the movable substrate 52 is, for example, about 200 μm. Therefore, the overall thickness dimension of the wavelength variable interference filter 5 can be suppressed to a thickness dimension of 1 mm or less.

  In the present embodiment, the substrate outer peripheral portion 525 is fixed to the control substrate 134 on the surface (light emitting surface) opposite to the fixed substrate 51 of the movable substrate 52 of the wavelength variable interference filter 5. The control board 134 has a terminal portion to which the fixed electrode pad 563P and the movable electrode pad 564P are connected. For example, the pads 563P and 564P are connected to the terminal portion by FPC (Flexible printed circuits) or the like. Further, as shown in FIG. 1, the imaging unit 133 is fixed to the surface of the control board 134 opposite to the surface on which the wavelength variable interference filter 5 is provided. Then, the light extracted by the multiple interference by the fixed reflective film 54 and the movable reflective film 55 passes through the light passage hole 134A provided in the control board 134 and is received by the imaging unit 133, so that the imaging unit 133 receives the light. A spectral image is captured. In other words, in the present embodiment, the variable wavelength interference filter 5 is attached to one surface of the control board 134 and the imaging unit 133 is attached to the other surface of the control board 134. The part 133 will be disposed in proximity. Thereby, the near infrared imaging module 13 can be further reduced in thickness, and the spectral camera 10 can be reduced in size and thickness.

Although the wavelength variable interference filter 5 is fixed to the control board 134, the present invention is not limited to this. For example, the wavelength variable interference filter 5 is stored in a package, and the package is fixed to the control board 134. It is good also as a structure. Furthermore, the wavelength tunable interference filter 5 is fixed to a substrate other than the control substrate 134 or a fixed portion provided in the housing 11, and the wavelength tunable interference filter 5 and the control substrate 134 are provided close to each other. It is good also as a structure etc. which are made.
Moreover, in this embodiment, since a color image is imaged by the visible light imaging module 12, the near-infrared imaging module 13 should just image | photograph the spectral image in a near infrared region. Therefore, in order to block visible light (and ultraviolet light) transmitted as the second and subsequent peak wavelengths among the light transmitted through the tunable interference filter 5, for example, a near-infrared wavelength light is transmitted. An infrared high pass filter may be provided. Such a near-infrared high-pass filter may be provided at any position on the optical path of incident light in the near-infrared imaging module 13, for example, between the imaging unit 133 and the wavelength variable interference filter 5. In addition, examples include the light incident unit 131 and the wavelength variable interference filter 5, the lens group of the light incident unit 131, the near-infrared imaging window 112 of the spectroscopic camera 10, and the like.

(Filter characteristics of wavelength variable interference filter 5)
FIG. 4 is a diagram showing the filter characteristics (transmittance) of the wavelength variable interference filter 5.
The wavelength variable interference filter 5 has different transmittance characteristics (filter characteristics) for each wavelength depending on the reflectance characteristics of the reflective films 54 and 55.
In the wavelength tunable interference filter 5 of this embodiment, when the voltage applied to the electrostatic actuator 56 is sequentially increased and the gap G1 between the reflection films is switched to a smaller gap amount, the light transmitted through the wavelength tunable interference filter 5 is reduced. The peak wavelength also shifts from the long wavelength side to the short wavelength side. At this time, as shown in FIG. 4, the light transmittance increases as the wavelength shifts from the long wavelength side to the short wavelength side. Therefore, even if the reference light having the same light quantity at each wavelength is incident on the wavelength variable interference filter 5, the wavelengths of the light transmitted through the wavelength variable interference filter 5 are different from each other.

(Configuration of imaging unit 133 and light receiving characteristics)
The imaging unit 133 includes a plurality of imaging elements that receive near-infrared light that has passed through the wavelength variable interference filter 5. As such an imaging unit 133, for example, an image sensor such as a CCD or a CMOS can be used. In this embodiment, since the visible light imaging module 12 captures a color image, the imaging unit 133 only needs to capture a monochrome image with a predetermined wavelength in the infrared region, and an imaging device for capturing a monochrome image is used. One image sensor is provided for one pixel. In such an imaging unit 133, for example, a light receiving surface per pixel can be increased compared to an imaging unit for color image imaging in which an imaging element corresponding to R, G, and B needs to be arranged in one pixel, and the measurement target The light quantity of the wavelength can be received more efficiently. Thereby, a sufficient amount of received light necessary for spectroscopic measurement can be ensured, and measurement accuracy can be improved.

FIG. 5 is a diagram illustrating the light receiving characteristics (sensitivity characteristics) of the imaging unit 133 according to the present embodiment.
In the present embodiment, as shown in FIG. 5, the imaging unit 133 uses an imaging element such as a GaAs photosensor that has low sensitivity in the ultraviolet to visible light range and high sensitivity characteristics in the near infrared range. .
As described above, in the configuration in which a near-infrared high-pass filter is provided in the optical path, an image sensor having sensitivity characteristics for a wide range from the near-infrared region to the visible light region (or ultraviolet region) is used as the imaging unit 133. It may be used.

(Configuration of the light source unit 132)
FIG. 6 is a diagram illustrating an arrangement example of the light sources 132 </ b> A constituting the light source unit 132. FIG. 7 is a diagram showing the positional relationship between each light source 132 </ b> A, the imaging unit 133, and the wavelength variable interference filter 5.
As shown in FIG. 6, the light source unit 132 includes a plurality of light sources 132 </ b> A arranged in an annular shape along the outer peripheral portion of the near-infrared imaging window 112. Specifically, as shown in FIG. 7, the light path length until the light emitted from each light source 132A is reflected by the measurement object (imaging object) X and received by the imaging unit 133 is constant. Each light source 132A is arranged at a position where the distance between each light source 132A and the imaging unit 133 is equal. In such a configuration, since the optical path length of each light source 132A is constant, it is not necessary to perform processing such as light amount correction due to the difference in optical path length, and the configuration and processing can be simplified.
Further, as the light source 132A, it is preferable to use an LED, a laser light source, or the like. When an LED or a laser light source is used, the light source unit 132 can be reduced in size and power consumption.

FIG. 8 shows a spectral spectrum (light emission intensity characteristic) of illumination light emitted from each light source 132A of the light source unit 132 of the present embodiment.
The light source unit 132 includes a plurality of types of light sources 132A having different emission wavelength ranges. In the present embodiment, as shown in FIG. 8, the first light source 132A1 (see FIG. 11) having an emission wavelength range of about 700 nm to 950 nm and the second light source 132A2 (FIG. 11) having an emission wavelength range of about 850 nm to 1120 nm. Reference).
The light source 132A may be configured to cover a near infrared wavelength region of, for example, 700 nm to 1200 nm by combining three or more types of light sources 132A having a narrower emission wavelength region (for example, about 50 to 100 nm).
Further, in the example shown in FIG. 8, the emission spectra of the first light source 132A1 and the second light source 132A2 that are necessary for capturing the near-infrared spectral image by the near-infrared imaging module 13 are shown. It is good also as a structure provided with the visible light source for imaging the picked-up image of visible light with the optical imaging module 12. FIG.

(Light emission intensity of the light source 132A)
The light emission intensity of each light source 132A as shown in FIG. 8 is set based on the filter characteristic (transmittance) of the wavelength variable interference filter 5 and the light reception characteristic (sensitivity) of the imaging unit 133.
FIG. 9 is a diagram in which the light emission intensity characteristic of the light source 132A, the transmittance characteristic of the variable wavelength interference filter 5, and the sensitivity characteristic of the imaging unit 133 are superimposed. FIG. 10 is a diagram showing optical characteristics of the near-infrared imaging module 13 obtained by multiplying the light emission intensity characteristics of the light source 132A, the transmittance characteristics of the wavelength variable interference filter 5, and the sensitivity characteristics of the imaging section 133.
The imaging unit 133 receives light and outputs a signal corresponding to the amount of received light. At this time, the signal value output by the imaging unit 133 is the transmittance characteristic of the variable wavelength interference filter 5 as shown in FIG. 4 and the imaging unit 133 as shown in FIG. 5 with respect to the light intensity of the received light. This value is multiplied by the sensitivity characteristic. In this embodiment, a reference calibration plate that does not absorb near-infrared light is used as the measurement object X, and the wavelength variable interference filter 5 is driven to switch the wavelength of the transmitted light in order. When the light is received by the imaging unit 133, as shown in FIG. 10, the light emission intensity (when a predetermined drive voltage is applied) of the light source 132A so that the light intensity (light reception amount) of the light of each wavelength is uniform. Light intensity) is set. Here, the term “uniform” is not limited to the case where the light intensity is strictly the same value, but includes, for example, an error that does not interfere with spectroscopic measurement.
The light emission intensity can be set, for example, by using a light source capable of emitting light having a predetermined light emission intensity as the light source 132A, or by the number of the light sources 132A. For example, if the light emission intensity when a predetermined drive voltage is applied to the first light source 132A1 cannot be sufficiently secured, the number of the first light sources 132A1 may be increased.

(Configuration of control board 134)
The control board 134 is a circuit board that controls the operation of the near-infrared imaging module 13, and is connected to the light incident part 131, the light source part 132, the variable wavelength interference filter 5, and the imaging part 133. In addition, the control board 134 includes a light incident unit driving circuit for driving the light incident unit 131, a voltage control circuit for applying a voltage to the electrostatic actuator 56 of the wavelength variable interference filter 5, and a light source driving circuit for driving the light source unit 132. An image pickup unit control circuit that controls driving of the image pickup unit 133 is provided, and the operation of each component is controlled based on a control signal input from the control unit 17. For example, when a zoom operation is performed by the user, the light incident unit driving circuit moves a predetermined lens of the light incident unit 131 or changes the aperture diameter of the diaphragm. When an operation for acquiring a spectral image is performed, the light source driving circuit controls turning on and off of each light source 132A of the light source unit 132, and the voltage control circuit applies a predetermined voltage based on the control signal to the electrostatic actuator 56. Apply to. Then, the imaging control circuit acquires a spectral image signal (spectral image) input from the imaging unit 133 at a predetermined timing, and outputs it to the control unit 17.

(Configuration of display 15)
The display 15 is provided facing the display window 114 of the housing 11. The display 15 may have any configuration as long as it can display an image. Examples thereof include a liquid crystal panel and an organic EL panel.
In addition, the display 15 of the present embodiment also serves as a touch panel and functions as one of the operation units 16.

(Configuration of operation unit 16)
As described above, the operation unit 16 includes a shutter button provided on the side surface 11C, a touch panel provided on the display 15, and the like. When an input operation is performed by the user, the operation unit 16 outputs an operation signal corresponding to the input operation to the control unit 17. Note that the operation unit 16 is not limited to the above-described configuration, and may be, for example, a configuration in which a plurality of operation buttons or the like are provided instead of the touch panel.

(Configuration of control unit 17)
FIG. 11 is a block diagram illustrating a schematic configuration of the spectroscopic camera 10.
The control unit 17 is configured by combining a CPU, a memory, and the like, for example, and controls the overall operation of the spectroscopic camera 10. As shown in FIG. 11, the control unit 17 includes a storage unit 18 (storage unit) and a calculation unit 19.

The storage unit 18 stores an OS for controlling the overall operation of the spectroscopic camera 10, programs for realizing various functions, and various data. The storage unit 18 includes a temporary storage area for temporarily storing the acquired spectral image, color image, component analysis result, and the like.
In the storage unit 18, as various data, V-λ data indicating the relationship of the wavelength of light transmitted through the wavelength tunable interference filter 5 with respect to the drive voltage applied to the electrostatic actuator 56 of the wavelength tunable interference filter 5. Is memorized.

The calculation unit 19 executes various processes by reading a program stored in the storage unit 18 and functions as a light source control unit 191, a filter control unit 192, a spectral image acquisition unit 193, and the like. The arithmetic unit 19 controls the driving of the visible light imaging module 12 and causes the display 15 to display a visible light image obtained by the visible light imaging module 12 and a spectral image obtained by the near infrared imaging module 13. Or
In the present embodiment, the light source control unit 191, the filter control unit 192, and the spectral image acquisition unit 193 are configured as software, but may be configured as hardware by a circuit such as an IC.

  The light source control unit 191 controls the driving state of each light source 132 </ b> A of the light source unit 132. Specifically, the light source 132A in the emission wavelength range corresponding to the target wavelength of the light transmitted through the wavelength tunable interference filter 5 is turned on (ON), and the light sources 132A in other emission wavelength ranges are turned off (OFF). In the band where the emission wavelength ranges of the plurality of light sources 132A overlap (for example, in the vicinity of 900 nm shown in FIG. 8), the plurality of light sources 132A may be turned on simultaneously to increase the amount of light.

  Based on the V-λ data stored in the storage unit 18, the filter control unit 192 sets a drive voltage for setting the wavelength of light extracted by the wavelength variable interference filter 5, and outputs a control signal to the control board 134. To do.

  The spectral image acquisition unit 193 acquires a signal output from the imaging unit 133 in a state in which stable light is emitted from the light source 132A and the vibration of the inter-reflection film gap G1 of the wavelength variable interference filter 5 is stationary. That is, a spectral image captured by the imaging unit 133 is acquired.

[Spectral Image Acquisition Processing of Measurement Object by Spectroscopic Camera 10]
Next, a spectral image acquisition process (spectral measurement method) by the spectral camera 10 as described above will be described below with reference to the drawings.
FIG. 12 is a flowchart of spectral image acquisition processing by the spectral camera 10.
FIG. 13 is a timing chart showing spectral image acquisition timing. In FIG. 13, the solid lines indicate the drive voltage (on / off signal) applied to the first light source 132A1 and the second light source 132A2, the drive voltage Vn applied to the electrostatic actuator 56, and the image captured by the imaging unit 133 (spectral spectrum). An on / off signal for acquiring (exposure) is shown. A broken line indicates a change in emission intensity in each light source 132A and a change in the gap between the reflection film gaps G1.
In the spectroscopic camera 10 of the present embodiment, for example, when the operator performs a shutter operation, a spectroscopic image in the near-infrared region of the measurement target X (imaging target) is acquired at a predetermined wavelength interval (for example, 50 nm pitch).
For this, the spectroscopic camera 10 first drives the wavelength variable interference filter 5 and the light source unit 132 (S1).
Specifically, the filter control unit 192 sets a target wavelength to be transmitted through the wavelength variable interference filter 5 and reads a target voltage corresponding to the target wavelength based on the V-λ data stored in the storage unit 18. Then, the filter control means 192 outputs a control signal for applying the read target voltage to the electrostatic actuator 56 to the control board 134. As a result, a drive voltage (target voltage) is applied to the electrostatic actuator 56 of the wavelength variable interference filter 5 from the voltage control circuit provided on the control board 134.

  At this time, the light source control means 191 outputs a control signal to the control board 134 to turn on the light source 132A including the set target wavelength in the emission wavelength range and to turn off the light source 132A not including the target wavelength in the emission wavelength range. . Accordingly, an on / off signal for switching on / off is output from the light source driving circuit of the control board 134 to each light source 132A of the light source unit 132.

Therefore, as shown in FIG. 13, the timing at which a predetermined target voltage is applied to the electrostatic actuator 56 of the wavelength tunable interference filter 5 and the on / off switching timing of each light source 132A of the light source unit 132 are the same timing. It is implemented by T (2n-1) (n is a natural number).
Although the present embodiment shows an example in which the voltage application timing for applying a voltage to the electrostatic actuator 56 of the variable wavelength interference filter 5 and the light source switching timing for switching the light source 132A are the same timing, the present invention is not limited to this. For example, after being applied to the electrostatic actuator 56, the light source 132A is switched until the vibration of the movable portion 521 stops (between timings T2n-1 to T2n in FIG. 13), and a stable light quantity is generated at the timing T2n. It only needs to be output.

Thereafter, the spectral image acquisition unit 193 acquires the light received by the imaging unit 133, that is, acquires a captured image at timings T2n to T2n-1 illustrated in FIG. 13 (S2). Specifically, the exposure on / off state of the imaging unit 133 is switched. In the exposure on state, the imaging unit 133 is driven, and a detection signal corresponding to the amount of received light, that is, a spectral image is input to the control unit 17. On the other hand, in the exposure off state, the imaging unit 133 is not driven, and no detection signal is output.
Note that the exposure on / off state may be switched by switching the driving / non-driving of the imaging unit 133 under the control of the control unit 17. For example, a shutter is provided in front of the imaging unit 133, and the exposure on state ( The shutter may be switched between the shutter open state and the exposure off state (shutter closed).
Between the timings T2n to T2n-1, as described above, the gap G1 between the reflection films of the wavelength tunable interference filter 5 is stable with a gap amount corresponding to the target wavelength, and stable light is output from the light source unit 132. Has been. Therefore, the spectral image acquisition unit 193 can acquire a spectral image for a desired target wavelength with high accuracy.
At this time, since the light source 132A that does not include the target wavelength for which the spectral image is to be acquired as the emission wavelength region is turned off by the above S1, power saving in the light source unit 132 can be achieved.

  Thereafter, the filter control means 192 determines whether there is another target wavelength (S3). That is, in the present embodiment, the wavelength of light transmitted through the wavelength variable interference filter 5 is switched from a predetermined upper limit measurement wavelength to a lower limit measurement wavelength at a predetermined pitch (for example, 50 nm pitch), and a spectral image for each wavelength is acquired. In S3, it is determined whether or not a spectral image for the lower limit measurement wavelength has been acquired.

In S3, when it is determined that a spectral image for the lower limit measurement wavelength has not been acquired and there are other wavelengths to be measured (when determined as “Yes”), the process returns to S1. That is, after setting the inter-reflective film gap G1 to the first gap and extracting the light of the first wavelength, the inter-reflective film gap G1 is set to extract the light of the second wavelength that is subsequently performed. The light source control means 191 turns on the light source 132A including the set target wavelength in the emission wavelength region until the gap is changed to 2 and when measurement is not performed (exposure off state). A control signal for turning off the light sources 132A not included in the emission wavelength range is output to the control board 134.
On the other hand, in S3, when a spectral image from the upper limit measurement wavelength to the lower limit measurement wavelength is acquired and it is determined that no other wavelength to be measured remains (when it is determined “No”), the calculation unit 19 Terminates the spectral image acquisition process, for example, acquires the spectral image from the obtained spectral image on the display 15 or outputs the spectral image to an external device connected to the spectral camera 10. Moreover, the calculating part 19 may implement the component analysis etc. of the measuring object X based on the acquired spectral image, for example.

[Operational effects of the first embodiment]
In the spectroscopic camera 10 of the present embodiment, light is irradiated from the light source unit 132 to the measurement target X, and the light reflected by the measurement target X is transmitted by adjusting the gap amount between the reflection films 54 and 55. Is incident on the wavelength tunable interference filter 5 and the light extracted by the reflecting films 54 and 55 is received by the imaging unit 133. In such a wavelength tunable interference filter 5, the fixed substrate 51 provided with the fixed reflection film 54, the movable substrate 52 provided with the movable reflection film 55, and the electrostatic for adjusting the gap between the reflection film gaps G <b> 1. This is an optical device including an actuator 56, and the thickness dimension can be reduced as compared with, for example, LCTF, AOTF, or the like. Therefore, by using such a wavelength tunable interference filter 5, the spectral camera 10 can be downsized and thinned, and can have a size suitable for carrying.

On the other hand, in portable devices, the battery capacity that can be mounted is limited, so it is important to efficiently save power.
On the other hand, in the present embodiment, the light source control unit 191 drives the light source 132A capable of emitting light corresponding to the target wavelength among the plurality of light sources 132A constituting the light source unit 132 and having different emission wavelength ranges ( The other light sources 132A are turned off. Thus, power consumption for driving the light source 132A can be reduced, and power saving that is essential for the portable device can be achieved.

By the way, when driving the light source 132A, as shown in FIG. 13, after applying a driving voltage to the light source 132A, a predetermined delay time occurs until light is stably emitted from the light source 132A. Also in the wavelength tunable interference filter 5, when a driving voltage is applied to the electrostatic actuator 56, the movable portion 521 vibrates due to the elasticity of the movable substrate 52, so that the vibration of the movable portion 521 converges (stills) and is desired. A predetermined delay time (stabilization time) is required until the target wavelength becomes transparent. Therefore, for example, when the light source 132A is driven after setting the drive voltage to the wavelength variable interference filter 5 to stop the vibration of the movable part 521, the time required for suppressing the vibration of the movable part 521 and the stability of the light source 132A It becomes necessary to wait for both of the time required for driving, and it becomes difficult to quickly acquire a spectral image.
On the other hand, in the present embodiment, in the process of S1, the light source 132A is switched in the light source unit 132 at the timing T2n-1 at which the drive voltage is applied to the wavelength variable interference filter 5. Thereby, the light emission intensity of the light source unit 132 can be stabilized during the time until the vibration of the movable unit 521 stops (timing T2n-1 to T2n).
Thereby, in the spectroscopic camera 10 of this embodiment, a spectroscopic image can be acquired rapidly.

Each light source 132A of the light source unit 132 of the present embodiment has a uniform signal (light intensity) output from the imaging unit 133 based on the transmittance characteristic of the wavelength variable interference filter 5 and the light receiving sensitivity characteristic of the imaging unit 133. Thus, the light emission intensity of each light source 132A is set. That is, using the reference calibration plate as the measurement target X, the light emission intensity for each wavelength of each light source 132A is set so that the light intensity becomes uniform when the light intensity of the light of each wavelength is detected.
For this reason, there is no inconvenience that the detection accuracy of light of a specific wavelength is lowered, and a spectral image of each wavelength can be acquired with high accuracy, and an accurate spectral image can be acquired for each wavelength.
Further, it is not necessary to perform a light intensity correction process on the spectral images of the respective wavelengths, and correction data or the like is not necessary, so that the process can be simplified.

  Each light source 132A constituting the light source unit 132 of the present embodiment uses an LED or a laser light source. For this reason, it is possible to further save power when the light source 132A is driven.

In the present embodiment, each light source 132 </ b> A is arranged at a position that is equidistant from the imaging unit 133.
In such a configuration, the light path length until the light emitted from the light source 132A is reflected by the measurement target X and enters the imaging unit 133 is constant in each light source 132A, and the light intensity due to the difference in the light path length, etc. It is not necessary to perform the correction process, and the process can be simplified.

[Second Embodiment]
Next, a second embodiment of the present invention will be described based on the drawings.
In the first embodiment, the example in which the light emission intensity of each light source 132A of the light source unit 132 is set based on the transmittance characteristic of the wavelength variable interference filter 5 and the light receiving sensitivity characteristic of the imaging unit 133 has been described. On the other hand, in the present embodiment, the light source control means 191 uses the transmission characteristics of the wavelength variable interference filter 5 and the light reception sensitivity characteristics of the imaging unit 133 to drive the light sources 132A. It differs from the first embodiment in that it is set.
Since the present embodiment has the same configuration as the first embodiment, the present embodiment will be described based on FIGS. 1 to 13.

Specifically, the storage unit 18 of the control unit 17 of the present embodiment stores light source driving data indicating the relationship of the driving voltage of each light source 132A with respect to the wavelength of the spectral image captured by the imaging unit 133.
This light source drive data uses a reference calibration plate that does not absorb near-infrared light as the measurement target X, drives the wavelength variable interference filter 5 to sequentially switch the wavelength of transmitted light, and extracts the extracted light of each wavelength. As shown in FIG. 10, when the image capturing unit 133 receives light, the driving voltage of the light source 132A for each wavelength is set so that the light intensity of each wavelength becomes uniform.
Accordingly, when driving the light source 132A in S1 in FIG. 12, the light source control means 191 turns on only the light source 132A including the target wavelength in the emission wavelength range, and corresponds to the target wavelength based on the optical drive data. The light source 132A is driven by the driving voltage.

Thereby, in this embodiment, it becomes possible to adjust the light intensity in more detail for each wavelength. For example, when the light source 132A having an emission wavelength range from the wavelength λ1 to the wavelength λ2 is driven with a constant drive voltage, the emission intensity at the wavelength λ1 and the emission intensity at the wavelength λ2 are fixed emission intensity. Even in this case, when the light receiving sensitivity characteristic of the imaging unit 133 and the transmittance characteristic of the wavelength variable interference filter 5 are multiplied, a substantially uniform light intensity as shown in FIG. 10 is obtained. However, the degree of freedom in design is reduced, and the light intensity for each wavelength varies slightly.
On the other hand, by controlling the driving voltage when driving each light source 132A as in this embodiment, the light intensity for each wavelength can be made more precise and uniform. That is, the peak height of each wavelength shown in FIG. 10 can be more accurately adjusted to the same height, and a more accurate spectral image can be acquired.
Further, even in the case where there is some variation in the light emission intensity for each wavelength in the spectral distribution within the light emission wavelength region of the light source 132A, the light emission intensity can be adjusted by adjusting the drive voltage applied to the light source 132A. Accordingly, the design freedom of the light source 132A is increased, and the manufacturing cost can be reduced.

  Here, an example in which the drive voltage to be applied to the light source 132A is set is shown, but the present invention is not limited to this. For example, the number of light sources 132A to be lit may be changed.

[Third embodiment]
Next, a third embodiment of the present invention will be described based on the drawings.
In the first and second embodiments, as the electronic device, the spectral camera 10 that receives light emitted from the wavelength variable interference filter 5 by the imaging unit 133 that is a light receiving unit and acquires a spectral image is exemplified.
On the other hand, in the electronic device of the present embodiment, an illumination device that makes light emitted from the light source unit incident on the wavelength variable interference filter and emits light of a predetermined wavelength that has passed through the wavelength variable interference filter is illustrated. .

FIG. 14 is a block diagram illustrating a schematic configuration of the illumination device of the present embodiment.
As illustrated in FIG. 14, the illumination device 20 includes a light source unit 132, the variable wavelength interference filter 5, and an illumination control unit 21. In addition, about the structure similar to 1st embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted or simplified.
In the illumination device 20 of the present embodiment, the light emitted from the light source unit 132 is first incident on the wavelength tunable interference filter 5, and the light transmitted through the wavelength tunable interference filter 5 is incident on an illumination optical system (not shown). The light is emitted from the illumination optical system to the outside.
Here, an example is shown in which light is emitted from the illumination optical system to the outside, but the light that has passed through the wavelength variable interference filter 5 may be transmitted to another optical device, for example, by an optical fiber or the like.

In addition, the emission wavelength range of each light source 132A of the light source unit 132 in the present embodiment is appropriately set based on the filter characteristics (transmittance characteristics) of the wavelength variable interference filter 5.
That is, each light source 132A has a light emission intensity set for each wavelength so that light of uniform light intensity is emitted when the reflection film gap G1 of the wavelength tunable interference filter 5 is sequentially switched and driven. Yes. That is, the light emission intensity is set so that the value obtained by multiplying the light emission intensity for each wavelength of each light source 132A by the transmittance characteristic of the wavelength variable interference filter 5 for the wavelength becomes constant.
The light emission intensity of each light source 132A is set such that the value obtained by multiplying the light emission intensity of each light source 132A with respect to each wavelength by the transmittance characteristic of the wavelength variable interference filter 5 with respect to that wavelength is equal to or greater than a predetermined value. Also good. As this predetermined value, it can change suitably by use of the illuminating device 20, etc. FIG.
Further, as in the second embodiment, the drive voltage of the light source 132A with respect to the target wavelength is stored in the storage unit 212, and the light emission intensity is adjusted by switching the drive voltage to the light source 132A according to the wavelength of the emitted light. It is good also as a possible structure.

The illumination control unit 21 includes a calculation unit 211 and a storage unit 212. As in the first embodiment, the storage unit 212 stores V-λ data indicating the relationship of the wavelength of light transmitted through the wavelength tunable interference filter 5 with respect to the voltage applied to the electrostatic actuator 56 of the wavelength tunable interference filter 5. Is memorized. As described above, when the drive voltage to the light source 132A is switched according to the target wavelength, the drive voltage of the light source 132A with respect to the wavelength of the emitted light may be recorded.
The calculation unit 211 functions as the light source control unit 213 and the filter control unit 214 by reading a program stored in the storage unit 212, for example.
The light source control unit 213 drives the light source 132A corresponding to the wavelength of the light transmitted through the wavelength variable interference filter 5, similarly to the light source control unit 191 of the first embodiment.
The filter control unit 214 controls driving of the wavelength variable interference filter 5 based on the V-λ data.

[Operation of Lighting Device 20]
Next, operation | movement of the above illuminating devices 20 is demonstrated.
FIG. 15 is a flowchart of the illumination process in the present embodiment.
In the illuminating device 20 of this embodiment, when the operation part which is not shown in figure is operated by the operator, the calculating part 211 sets the target wavelength of the light radiate | emitted from the illuminating device 20 (S11).

Thereafter, the illumination device 20 performs the same processing as S1 of the first embodiment, and drives the wavelength variable interference filter 5 and the light source unit 132 (S12). That is, the filter control unit 214 reads the target voltage corresponding to the target wavelength set in S11 based on the V-λ data stored in the storage unit 18. Then, the filter control means 214 outputs a control signal for applying the read target voltage to the electrostatic actuator 56 to a filter voltage control circuit (not shown). Thereby, the electrostatic actuator 56 is driven, and the movable portion 521 is displaced so that the gap G1 between the reflection films becomes a predetermined gap amount.
At this time, the light source control means 213 turns on the light source 132A including the target wavelength set in S11 in the emission wavelength region, and turns off the light source 132A not including the target wavelength in the emission wavelength region.
Thereby, also in this embodiment, the light source unit 132 can be stably driven until the vibration of the movable unit 521 of the wavelength tunable interference filter 5 converges, and the movable unit 521 of the wavelength tunable interference filter 5 can be driven. In a state where the vibration has converged, light having a predetermined target wavelength is stably emitted from the illumination optical system.

Thereafter, the calculation unit 211 determines whether or not an operation for changing the setting of the target wavelength has been performed by the operation of the operator's operation unit (S13).
In S13, when an operation for changing the target wavelength is performed (when determined as “Yes”), the process returns to S11.
On the other hand, if it is determined as “No” in S13, the illumination process is continued. For example, when the operator performs an operation to stop the illumination, such as a power-off operation, the light source The lighting driving of 132A and the driving of the wavelength variable interference filter 5 are finished.

[Operational effects of the third embodiment]
Since the illuminating device 20 of this embodiment switches the wavelength of the emitted light using the wavelength variable interference filter 5, the illuminating device 20 can be reduced in size as in the first embodiment.
In addition, the light source control unit 213 turns on the light source 132A capable of emitting light corresponding to the target wavelength among the plurality of light sources 132A having different emission wavelength ranges, and turns off the other light sources 132A. Thereby, the power consumption concerning the drive of the light source 132A can be reduced similarly to said 1st embodiment.
Furthermore, in this embodiment, since the light source 132A is switched in the light source unit 132 at the timing of applying the drive voltage to the wavelength variable interference filter 5 in the process of S12, the vibration until the vibration of the movable unit 521 converges. In addition, the light from the light source 132A can be stabilized, and the illumination apparatus 20 can quickly emit a desired target wavelength.

Each light source 132 </ b> A of the light source unit 132 of the present embodiment is configured so that the wavelength of light emitted from the illumination device 20 is uniform or has a certain light intensity or more based on the transmittance characteristics of the wavelength variable interference filter 5. In addition, the emission intensity of each light source 132A is set.
For this reason, it is possible to emit light having a constant light intensity when emitting light of any wavelength.

[Modification]
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 first and second embodiments, the spectroscopic camera 10 includes the visible light imaging module 12, and an example in which a color image is captured by the visible light imaging module 12 is shown. On the other hand, the visible light imaging module 12 may not be provided. In this case, the spectral image captured by the near infrared imaging module 13 may be displayed on the display 15.
Further, the variable wavelength interference filter 5 may be configured to be able to disperse light having a predetermined wavelength in the visible light region to the near infrared region, and a color image is captured by the near infrared imaging module 13 instead of the visible light imaging module 12. can do.

In the first and second embodiments, the configuration in which the control substrate 134 is interposed between the wavelength tunable interference filter 5 and the imaging unit 133 is illustrated, but the imaging unit 133 is directly on the light emission surface of the wavelength tunable interference filter 5. It is good also as a structure fixed. Further, the variable wavelength interference filter 5 and the imaging unit 133 may be directly or indirectly fixed to a fixing piece or the like provided inside the housing 11. In this case, it is preferable to arrange the wavelength variable interference filter 5 and the imaging unit 133 close to each other, for example, by fixing the wavelength variable interference filter 5 and the imaging unit 133 in contact with each other.
In addition, the wavelength variable interference filter 5 is not limited to a single unit and is housed in the housing 11. For example, the wavelength variable interference filter 5 is housed in an optical package provided with a light passage hole. May be stored in the housing 11. Even in this case, by providing a terminal portion connected to the fixed electrode pad 563P and the movable electrode pad 564P of the wavelength variable interference filter 5 on the outer surface of the optical package, the static variable provided in the wavelength variable interference filter 5 inside the optical package is provided. A voltage can be applied to the electric actuator 56.
Furthermore, although the example in which the wavelength variable interference filter 5 and the imaging unit 133 are fixed to the control board 134 is shown, a configuration in which the wavelength variable interference filter 5 and the imaging unit 133 are fixed to another board may be used.

Although the wavelength variable interference filter 5 includes the electrostatic actuator 56 that varies the gap amount of the gap G1 between the reflection films by applying a voltage, the wavelength variable interference filter 5 is not limited thereto.
For example, instead of the fixed electrode 561, a first dielectric coil may be arranged, and a dielectric actuator in which a second dielectric coil or a permanent magnet is arranged instead of the movable electrode 562 may be used.
Further, a piezoelectric actuator may be used instead of the electrostatic actuator 56. In this case, for example, the lower electrode layer, the piezoelectric film, and the upper electrode layer are stacked on the holding unit 522, and the voltage applied between the lower electrode layer and the upper electrode layer is varied as an input value, thereby expanding and contracting the piezoelectric film. Thus, the holding portion 522 can be bent.

  Moreover, in the said embodiment, although the small spectroscopic camera 10 and the illuminating device 20 which were portable were illustrated as an electronic device, For example, it can apply also to other portable electronic devices, such as a mobile telephone and a smart phone. In addition, the present invention can also be applied to a spectroscopic measurement device for measuring a spectroscopic spectrum to be measured, a component analysis device for analyzing a component contained in a test object such as food.

In the first and second embodiments, the driving timing of the light source unit 132 is the wavelength switching timing in the wavelength variable interference filter 5, but the present invention is not limited to this.
In general, in the variable wavelength interference filter 5, the incident angle θ of light, the refractive index n of the medium between the reflective films (1 in the case of air), the gap amount d of the gap between the reflective films, and the order m (m is an integer) In this case, light satisfying mλ = 2nd cos θ is extracted. That is, light having a plurality of peak wavelengths corresponding to the order m is extracted. Here, in each of the above embodiments, by switching the light source 132A to emit light, it is possible to extract only light having a peak wavelength of a predetermined target wavelength from among a plurality of peak wavelengths of the filter characteristics of the wavelength variable interference filter 5.
At this time, the light source 132A to be driven is switched at the switching timing (driving voltage application timing) of the gap between the reflection films of the wavelength tunable interference filter 5, and after taking a spectral image for the first peak wavelength, the wavelength tunable interference filter 5 is switched. The driving voltage may be maintained as it is, and only the light source 132A to be driven may be switched to perform processing for capturing a spectral image for the secondary peak wavelength.
In such processing, light of each peak wavelength corresponding to the order can be quickly acquired.

  In addition, the specific structure 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 5 ... Variable wavelength interference filter, 10 ... Spectral camera (electronic device), 11 ... Case, 13 ... Near infrared imaging module, 17 ... Control part, 18 ... Memory | storage part, 19 ... Calculation part, 20 ... Illuminating device (electronic) Equipment), 21 ... illumination control unit, 51 ... fixed substrate, 52 ... movable substrate, 54 ... fixed reflection film, 55 ... movable reflection film, 56 ... electrostatic actuator, 132 ... light source unit, 132A ... light source, 133 ... imaging unit (Light receiving unit), 191, 213... Light source control means, 192, 214... Filter control means, 193.

Claims (6)

Multiple light sources;
A variable wavelength interference filter in which two reflective film facing, and includes a gap changing portion that changes the gap, take out light with a wavelength of Jo Tokoro through the gap,
A control unit;
With
Each of the plurality of light sources has a different emission wavelength range,
The controller is
A light source control means for turning on a light source that emits light in a light emission wavelength region corresponding to a wavelength of light extracted by the wavelength variable interference filter among the plurality of light sources, and turning off other light sources;
Filter control means for controlling the gap changing unit and changing the wavelength of light taken out by the wavelength variable interference filter;
With
The light source control unit is configured to extract light of the second wavelength in the subsequent measurement after the filter control unit sets the gap to the first gap and extracts the light of the first wavelength. Until the gap is changed to the second gap and when the measurement is not performed , the first light source among the plurality of light sources turned off is turned on, A spectroscopic device characterized in that the second light source that has been lit is extinguished. The spectroscopic device according to claim 1,
A spectroscopic device comprising a light receiving unit that receives light extracted by the wavelength variable interference filter. The spectroscopic device according to claim 1 or 2,
The spectroscopic device , wherein the light emission intensities of the plurality of light sources are respectively set so as to obtain a uniform light intensity at each wavelength based on a filter characteristic of the wavelength variable interference filter. The spectroscopic device according to claim 2,
The light emission intensity of the light source is set based on the light reception characteristics of the light receiving unit and the filter characteristics of the wavelength variable interference filter so that uniform light intensity can be obtained at each wavelength. Spectrometer . The spectroscopic device according to claim 1 or 2,
The spectroscopic device , wherein the light source control means drives the light source so that uniform light intensity is obtained at each wavelength based on a filter characteristic of the wavelength variable interference filter. The spectroscopic device according to claim 5,
A light receiving portion for receiving the light extracted by the wavelength variable interference filter;
The light source control means includes a light receiving characteristic of the light receiving portion, on the basis of the filter characteristic of the variable wavelength interference filter, wherein the uniform light intensity drives the light source so as to obtain at each wavelength spectroscopy Equipment .

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