JP2014010272A - Optical filter, optical filter device, and optical apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical filter in which a mirror part is formed for preventing unnecessary light from entering the mirror part.SOLUTION: An optical filter is light-transmissive, and comprises a first substrate having a first reflecting film on its first side, and a second substrate arranged opposite to the first side. The side of the second substrate, which is opposite to the first side, has a first recess, and a second recess arranged on the outer periphery of the first recess in a plane view, viewed from the thickness direction of the second substrate, and having a closed shape in the plane view. The distance between the first bottom part composing the bottom of the first recess and the second substrate is shorter than the distance between a second bottom part composing the bottom of the second recess and the second substrate. A second reflecting film is formed on the first bottom part. The second reflecting film is extended from the first bottom part to a face connecting the first bottom part and the second bottom part.

Description

  The present invention relates to an optical filter, an optical filter device, and an optical apparatus.

  Patent Document 1 discloses an optical filter configured by a Fabry-Perot etalon filter (hereinafter, sometimes referred to as an etalon filter or simply an etalon) having a pair of optical films facing each other with a predetermined gap therebetween.

  In the etalon filter described in Patent Document 1, a first substrate and a second substrate held in parallel with each other, a first reflective film formed on the first substrate, and a first gap having a predetermined gap. A second reflective film formed on the second substrate and facing the reflective film. Each of the first reflection film and the second reflection film constitutes a mirror, and light in a predetermined wavelength range corresponding to the length of the gap (gap amount) is obtained by causing multiple interference of light between the mirrors. Can only penetrate. Furthermore, the wavelength range of light that can be transmitted can be switched by configuring the gap amount to be variable.

JP 2009-134028 A

  Since the etalon filter uses multiple interference of light, the gap amount between the mirrors is extremely small, and the wavelength range of light that can be transmitted through the minute amount of gap is further changed. Yes. Therefore, in order to transmit light having a desired wavelength, it is necessary to control the optical axis so as to be incident from a direction orthogonal to the mirror. However, light that does not enter the mirror part from a direction that is exactly perpendicular to the mirror part is generated due to the sneak of incident light on the mirror or irregular reflection or scattering of part of the incident light at parts other than the mirror part. There is a possibility that an error may occur in a value to be obtained by an optical device including the above.

  Therefore, an optical filter is provided in which a mirror portion is formed to prevent unnecessary light from entering the mirror portion.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] An optical filter according to this application example has a light transmission property, a first substrate having a first reflection film on a first surface, and a light transmission property disposed opposite to the first surface. A surface of the second substrate that faces the first surface of the second substrate, the first recess, and the first substrate and the second substrate in a plan view as viewed from the thickness direction. A second recess that is disposed along the outer periphery of the first recess and is circumferential in the plan view, and the distance between the first bottom and the second substrate constituting the bottom surface of the first recess is the first A second reflection film is formed on the first bottom portion, and the second reflection film is formed from the first bottom portion to the first substrate. It extends to the surface which connects 1 bottom part and said 2nd bottom part, It is characterized by the above-mentioned.

  In the conventional optical filter, for example, diffracted light or refracted light generated by light incident on the optical filter is diffused inside the optical filter to become so-called stray light. In particular, stray light is generated in the vicinity of the reflecting portion of the second reflecting film facing the first reflecting film, so that it is added as noise to the light filtered by the multiple interference between the first reflecting film and the second reflecting film. There was a fear. According to the optical filter of this application example, the end portion of the second reflective film extends beyond the region facing the first reflective film, so that the stray light is generated at the reflective film where the multiple interference occurs. Therefore, it is possible to detect only accurately filtered wavelengths that do not overlap noise in the detection data.

  Application Example 2 In the application example described above, the second reflective film extends to the second bottom portion.

  According to the application example described above, the incident path of incident light that can become stray light can be further narrowed. Therefore, it is possible to obtain an optical filter that can detect only the wavelength filtered more accurately.

  [Application Example 3] The optical filter of this application example is light transmissive and has a first substrate provided with a first reflective film on a first surface, and is disposed opposite to the first surface to provide light transmissive properties. A second substrate having a first concave portion on a surface facing the first surface of the second substrate, and the first substrate and the second substrate in a plan view as viewed from the thickness direction. A second concave portion that is arranged outside the first concave portion and is circumferential in the plan view; and a third concave portion is formed outside the first concave portion and inside the second concave portion in the plan view. The distance between the first bottom portion and the second substrate is smaller than the distance between the second bottom portion and the second substrate constituting the bottom surface of the second recess, and the third bottom portion constituting the bottom surface of the third recess. Is smaller than the distance between the second substrate and the third recess, and the second reflective film is formed from the first bottom to the first Characterized in that to the bottom is extended.

  According to the application example described above, the incident path of incident light that can become stray light can be further narrowed, and the separation from the end of the second reflection film, which is easy to peel off from the substrate, and a part of the separated reflection film can be obtained. Intrusion into the optical filter can be suppressed by lengthening the discharge path from the third bottom to the opening of the third recess in the second bottom. Therefore, since it is possible to suppress a part of the reflection film separated into the gap between the reflection films of the very small first substrate and the second substrate from entering, a highly reliable optical filter can be obtained.

  Application Example 4 In the application example described above, electrodes are formed on the outer side of the first reflective film and on the second bottom portion of the first substrate.

  Application Example 5 In the above application example, the first surface of the first substrate and the substrate surface formed by the first recess, the second recess, and the third recess of the second substrate. An antireflection film is formed, and the antireflection film is not formed on at least the surface of the first reflection film and the surface of the second reflection film formed on the first bottom portion. .

  According to the application example described above, by providing the antireflection film, stray light generated inside the optical filter can be excluded outside the optical filter without being further reflected inside the optical filter. Therefore, stray light that overlaps data as noise can be suppressed, and an optical filter that can be accurately filtered in a predetermined wavelength range can be obtained.

  Application Example 6 In the application example described above, the antireflection film is TiNx or TiOx (where x is an integer of 1 or more).

  According to the application example described above, the reflectance can be reduced, and a high antireflection effect can be obtained. Therefore, stray light that overlaps data as noise can be suppressed, and an optical filter that can be accurately filtered in a predetermined wavelength range can be obtained.

  Application Example 7 An optical filter device according to this application example has a light transmission property, a first substrate having a first reflection film on a first surface, and a light transmission property disposed opposite to the first surface. A surface of the second substrate that faces the first surface of the second substrate, as viewed from the thickness direction of the first substrate and the second substrate. A distance between the first bottom portion and the second substrate forming a bottom surface of the first recess is formed along the outer periphery of the first recess in the plan view and formed in a circumferential shape in the plan view. Is smaller than the distance between the second bottom portion constituting the bottom surface of the second recess and the second substrate, and a second reflective film is formed on the first bottom portion, and the second reflective film is formed by the first reflective film. It extends from the bottom part to the surface which connects the said 1st bottom part and the said 2nd bottom part, It is characterized by the above-mentioned.

  According to the optical filter device of this application example, the end portion of the second reflective film extends beyond the region facing the first reflective film, so that the stray light is generated at the location where the light is subjected to multiple interference. Only accurately filtered wavelengths can be detected that can be spaced from the film region and do not overlap the detection data.

  Application Example 8 An optical device according to this application example includes the above-described optical filter.

  According to the optical device of this application example, it is possible to suppress stray light that is superimposed on data as noise, and by providing an optical filter that can accurately filter in a predetermined wavelength range, the optical device operates more accurately and stably. Can be obtained.

The optical filter which concerns on 1st Embodiment is shown, (a) is sectional drawing, (b) is a conceptual diagram explaining the 2nd board | substrate structure. (A) is a fragmentary sectional view of the 2nd board | substrate of the optical filter which concerns on 1st Embodiment, (b) And (c) is a fragmentary sectional view which shows the example of other embodiment. The schematic diagram which shows the behavior of the incident light of the optical filter which concerns on 1st Embodiment. The fragmentary sectional view which shows the optical filter which concerns on other embodiment. The optical filter which concerns on 2nd Embodiment is shown, (a) is sectional drawing, (b) is the A section expanded sectional view shown to (a). The block diagram which shows the colorimeter which concerns on 3rd Embodiment. 10 is a flowchart showing the operation of a colorimeter according to a third embodiment. The block diagram which shows the transmitter which concerns on 4th Embodiment. Sectional drawing which shows the structure of the gas detection apparatus which concerns on other embodiment. The circuit block diagram of the gas detection apparatus which concerns on other embodiment. The block diagram which shows the structure of the food analyzer which concerns on other embodiment. The perspective view which shows the structure of the spectroscopic camera which concerns on other embodiment.

  Embodiments according to the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of the optical filter according to the first embodiment. As shown in FIG. 1A, the optical filter 100 according to the present embodiment is a so-called air gap type electrostatic drive type variable wavelength interference filter. The optical filter 100 includes a first substrate 10 and a second substrate 20 bonded to face the first substrate 10. The 1st board | substrate 10 and the 2nd board | substrate 20 have optical transparency, such as various glass, such as soda glass, crystalline glass, quartz glass, lead glass, potassium glass, borosilicate glass, an alkali free glass, and a crystal. Formed from material. Among these, glass containing an alkali metal such as sodium or potassium is preferable. By including an alkali metal, it is possible to improve the adhesion of the reflective film or electrode described later to the substrates 10 and 20.

  A circular first reflective film 30 is formed at the approximate center of the first surface 10a of the first substrate 10 facing the second substrate 20. Furthermore, annular electrodes 41 and 42 are formed around the first reflective film 30, and a first electrode 40 as an electrode of the first substrate 10 is configured. An annular recess 10c is formed on the surface 10b opposite to the first surface 10a corresponding to the first electrode 40, and a thin diaphragm portion 10d is formed in an annular shape.

The first reflective film 30 and the second reflective film 50 described later are composed of dielectric multilayer films in which a plurality of high refractive index layers and low refractive index layers are alternately stacked. When the optical filter 100 is used in the visible or infrared wavelength region, examples of the material for forming the high refractive index layer of the dielectric multilayer film include titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), and oxidation. Niobium (Nb ₂ O ₅ ) or the like is used, and as a material for forming the low refractive index layer, for example, magnesium fluoride (MgF ₂ ), silicon oxide (SiO ₂ ), or the like is used. When the optical filter 100 is used in the ultraviolet wavelength region, examples of the material for forming the high refractive layer include aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), zirconium oxide (ZrO ₂ ), and thorium oxide. (ThO ₂₎ and the like are used as the material for forming the low refractive index layer, such as magnesium fluoride (MgF _2), silicon oxide (SiO ₂₎ or the like is used.

  As shown in FIG. 1B, the second substrate 20 bonded to the first substrate 10 is opposed to the central portion of the second substrate 20 from the bonding surface 20 a side bonded to the first substrate 10. The bottom of the cylindrical first recess H1 constitutes a second reflective film forming surface 20b as the first bottom. Furthermore, an electrode forming surface 20c as a second bottom portion is constituted by the bottom portion of the annular second concave portion H2 formed around the first concave portion H1. An inner bottom surface 20d as a third bottom portion is formed around the first recess H1 by the bottom portion of the annular third recess H3 formed deeper than the second recess H2. As shown in FIG. 1B, the second reflection film forming surface 20 b is the bottom of the first recess H <b> 1 and the top surface of the columnar protrusion 20 e formed at the center of the second substrate 20.

  A second electrode 60 including electrodes 61 and 62 is formed on the electrode forming surface 20 c of the second substrate 20 so as to face the first electrode 40 formed on the first substrate 10. By forming the first electrode 40 and the second electrode 60 in this way, the direction, strength, etc. of the current passed through the electrodes 41, 42, 61, 62 are controlled by control means (not shown), and the first electrode 40 The diaphragm portion 10d formed on the first substrate 10 is flexibly deformed by the force with which the second electrode 60 is attracted. By bending the diaphragm portion 10d, a distance G (hereinafter referred to as a gap G) between the first reflective film 30 and a second reflective film 50 formed on a second reflective film forming surface 20b described later is changed. This is a so-called electrostatically driven air gap type optical filter 100 that changes the wavelength band that is filtered by the multiple interference of light.

  What is the bonding surface 20a of the second substrate 20? An annular light shielding portion 70 (hereinafter referred to as an aperture 70) having an opening 70a that overlaps the second reflective film forming surface 20b at least in plan view is formed on the substrate rear surface 20f. ing. The aperture 70 is formed of a light-shielding film, such as Cr, for preventing light other than the light filtered by the first reflective film 30 and the second reflective film 50 from passing through the optical filter 100.

  The second reflective film 50 formed on the second substrate 20 will be described in detail. As shown in FIG. 2A showing a partially enlarged view of the protrusion 20e, the protrusion 20e of the second substrate 20 covers at least the first reflection film 30 of the first substrate 10 so as to cover the second reflection film forming surface 20b. A second reflecting portion 50a of the second reflecting film 50 is formed opposite to the second reflecting film 50. A reflective film extending portion 50b is formed on the outer peripheral surface 20g of the protrusion 20e so that the second reflective film 50 extends from the second reflective portion 50a. The reflective film extending portion 50b extends to the inner bottom surface 20d formed by the third recess H3 and is formed so as to cover the entire outer peripheral surface 20g.

  The reflective film extending portion 50b is more preferably extended to the inner bottom surface 20d as shown in FIG. 2A, but is not limited thereto. For example, as shown in FIG. 2B, a reflective film extending portion 50b ′ extending so as to cover a part of the outer peripheral surface 20g of the protrusion 20e may be used. Furthermore, as shown in FIG. 2C, a reflective film extending portion 50b ″ formed in the region of the third recess H3 deeper than the electrode forming surface 20c is still more preferable.

FIG. 3 is a schematic diagram showing the behavior of incident light on the second substrate 20, and is an enlarged view of the portion of the second reflective film 50 described with reference to FIG. As shown in FIG. 3, the parallel light L filtered from the lower side of the second substrate 20 is incident. Of the parallel light L, when the parallel light L ₁ is transmitted through the outer peripheral portion of the protrusion 20e of the substrate 20, for example, the inner bottom surface 20d, when entering from the substrate back surface 20f of the second substrate 20 and exiting from the inner bottom surface 20d, A part of the parallel light L ₁ is diffused by refraction or diffraction at the inner bottom surface 20 d and scattered as scattered light L ₁ ′ inside the optical filter 100. But light L _1'' towards a portion of the protrusion 20e side of the scattered light L ₁ 'is reflected in the direction away from the first reflecting film 30 by the reflection Makunobe portion 50b of the second reflecting film 50.

However, for example, in the case of a configuration including only the second reflecting portion 50a which is also a configuration of a conventional optical filter, the light L _{2 that} is transmitted through the outer edge of the second reflecting portion 50a as a part of the parallel light L illustrated in FIG. 2 Diffused light L ₂ ′ diffused by refraction or diffraction by the substrate 20 at the outer edge of the reflecting portion 50 a is diffused into the optical filter. Of the diffused light L ₂ ′, the diffused light L ₂ ′ directed toward the first reflective film 30 may overlap with detection data obtained from the parallel light L as noise by a light detection unit (not shown).

  Therefore, if the second reflective film 50 has the reflective film extending portion 50b formed on the second substrate 20 included in the optical filter 100 according to the present embodiment, the detection data is accurately filtered without noise. An optical filter 100 that can detect only the wavelength can be obtained.

  In the optical filter 100 according to the present embodiment, the reflective film extending portions 50b and 50b, such as the reflective film extending portion 50b or the reflective film extending portion 50b ″ shown in FIGS. The end portions 50c, 50c ″ of the ″ are configured to be within a range facing the peripheral wall surface 20h extending from the electrode forming surface 20c to the inner bottom surface 20d formed by the third recess H3 in the outer peripheral surface 20g of the protrusion 20e. Has been. With such a configuration, the second reflective film 50 is separated from the second reflective film 50 by using the end portions 50c and 50c ″ as starting points due to insufficient adhesion between the second reflective film 50 and the second substrate 20 or deterioration of the adhesiveness. 50 is peeled, and a separation film (not shown) in which a part of the peeled film is separated from the second reflective film 50 is formed in the groove 20j formed by the peripheral wall surface 20h, the outer peripheral surface 20g, and the inner bottom surface 20d. It can be made to stay, and it is suppressed that it penetrates into the inside of the optical filter 100 of the separation film used as a foreign substance, especially between the 1st reflective film 30 comprised by the minute gap G, and the 2nd reflective part 50a.

  FIG. 4 is a partial cross-sectional view showing another form of the optical filter 100 according to the first embodiment. The same components as those of the optical filter 100 are denoted by the same reference numerals, and description thereof may be omitted. FIG. 4 is a partially enlarged view of a portion of the optical filter 110 where the first reflective film 30 and the second reflective film 50 are formed.

  As shown in FIG. 4, the optical filter 110 includes a first substrate 10 and a second substrate 21 bonded to face the first substrate 10, and the second substrate 21 is a second face facing the first substrate 10. It has a columnar projection 21a having a reflection film forming surface 21b where the second reflection portion 50a of the reflection film 50 is formed and an outer peripheral surface 21c where the reflection film extending portion 50b is formed. In addition, a peripheral wall surface 21e that faces the outer peripheral surface 21c of the protrusion 21a from the inner bottom surface 21d formed by the third recess H3 (see FIG. 1B) has an annular protrusion 21g formed on the electrode forming surface 21f. doing.

  By providing the annular protrusion 21g, the distance from the upper surface 21h to the inner bottom surface 21d of the annular protrusion 21g can be increased, that is, the peripheral wall surface 21e can be increased. Accordingly, the path from the end of the reflection film extending portion 50b of the second reflection film 50 to the part 50c is separated, and a part of the separated reflection film is discharged from the opening of the upper surface 21h of the annular protrusion 21g. Intrusion of a part of the separated reflective film into the optical filter 110 can be suppressed.

(Second Embodiment)
FIG. 5 is a cross-sectional view showing an optical filter according to the second embodiment. The same configurations as those of the optical filter 200 according to the second embodiment shown in FIG. 5 and the optical filter 100 or the optical filter 110 according to the first embodiment may be denoted by the same reference numerals, and description thereof may be omitted.

  In the optical filter 200 shown in FIG. 5A, an antireflection film 81 is formed on the surface of the first surface 10a on which the first reflective film 30 of the first substrate 10 is formed. In addition, the second substrate 20 includes the surface of the electrode forming surface 20c, the surface of the outer peripheral wall surface 20k of the second recess H2 (see FIG. 1), and the inner bottom surface 20d from the electrode forming surface 20c. As shown in FIG. 5B, which is an enlarged view of the portion A, an antireflection film 82 is formed on the surface of the reflection film extending portion 50b. The antireflection film 80 is not formed on at least the surface of the first reflection film 30 of the first substrate 10 and the surface of the second reflection part 50 a in the second reflection film 50 of the second substrate 20. That is, since the first reflective film 30 and the second reflective film 50 are composed of the dielectric multilayer film as described above, the antireflection film is superimposed on the dielectric multilayer film, so that light in a predetermined wavelength region is emitted. This is because it becomes difficult to perform accurate filtering.

The antireflection film 80 is formed of, for example, a single layer film or a multilayer film of a metal oxide film of TiN _x or TiO _x . Note that _x is an integer of 1 or more. By forming the antireflection film 80 from a single layer film or a multilayer film of a metal oxide film of TiN _x or TiO _x, a film having a high antireflection effect can be obtained. It is particularly preferable to use _TiN, or a TiO _2. Further, the antireflection film 80 is not limited to a thin film of TiN _x or TiO _x , and may be, for example, a single layer film or a multilayer film of an organic film as long as the reflectance can be reduced. Further, the antireflection film 80 does not need to prevent reflection by 100%, and it is sufficient that the reflectance can be lowered by absorbing or transmitting stray light.

  Thus, by providing the antireflection film 80, for example, the scattered light L1 ′ described with reference to FIG. 3 or the incident light other than the parallel light L1 incident on the opening 70a of the aperture 70 from the space between the inner bottom surface 20d in plan view. The light becomes so-called stray light inside the optical filter 200. This stray light causes the surface of the first surface 10a of the first substrate 10, the surface of the electrode forming surface 20c of the second substrate 20, the surface of the outer peripheral wall surface 20k of the second recess H2 (see FIG. 1), and the electrode forming surface 20c. As shown in FIG. 5 (b), which is an enlarged view of the A part shown in FIG. 5 (a), including the inner bottom surface 20d, the reflected stray light reflected on the surface of the reflective film extending part 50b There is a possibility that the data from the parallel light L of the detection data that is transmitted through the one reflection film 30 and obtained by the light detection means (not shown) overlaps with data as noise. Therefore, by providing the antireflection film 80, reflection of stray light on the inner surface of the optical filter 200 is suppressed, stray light is transmitted to the outside of the optical filter 200, and does not overlap with data from the parallel light L of the detection data as noise. Thus, an optical filter 200 that can be accurately filtered in a predetermined wavelength region can be obtained.

  As shown in FIGS. 5A and 5B, in this embodiment, the antireflection film 80 is formed so as to cover the electrodes 40 (41, 42) and 60 (61, 62). However, the present invention is not limited to this, and an antireflection film 80 may be formed between the electrodes 40, 60 and the electrode formation surface 20c. In addition, the configuration in which the antireflection film 80 is formed on substantially the entire surface of the optical filter 200 according to the present embodiment except for the first reflection film 30 and the second reflection part 50a of the second reflection film 50 is illustrated. However, the present invention is not limited to this, and an antireflection film may be partially formed.

(Third embodiment)
FIG. 6 shows a colorimeter that is one of analytical instruments as an example of an optical device according to the third embodiment, which includes the optical filters 100 and 110 according to the first embodiment or the optical filter 200 according to the second embodiment. It is a block diagram which shows schematic structure. In the description of this embodiment, a colorimeter including the optical filter 100 will be described.

  As shown in FIG. 6, the colorimeter 1000 includes a light source device 1100, a spectroscopic measurement device 1200, and a colorimetry control device 1300. The colorimeter 1000 emits, for example, emission light Ls that is white light from the light source device 1100 toward the inspection target B, and the inspection target light Lr that is light reflected by the inspection target B to the spectroscopic measurement device 1200. Make it incident. In the spectroscopic measurement device 1200, the inspection target light Lr is spectrally separated, and spectral characteristic measurement is performed to measure the amount of light of each wavelength separated. The spectroscopic measurement device 1200 includes the optical filter 100 according to the first embodiment, and the inspection target light Lr is incident on the optical filter 100, and the amount of light in a predetermined wavelength range to be transmitted is measured. The color measurement process is executed by the color included in the inspection object B from the light amount of the light in the region, that is, the amount including the light in each wavelength region.

  The light source device 1100 includes a light source 1110 and a plurality of lens groups 1120 (illustrated simply as one lens), and emits white light to the inspection target B as inspection light Ls. The lens group 1120 includes a collimator lens (not shown). The white light emitted from the light source 1110 is converted into parallel inspection light Ls by the collimator lens, and is directed from the projection lens (not shown) included in the lens group 1120 toward the inspection target B. And inject.

  The spectroscopic measurement device 1200 includes an optical filter 100, a light receiving unit 1210 including a light receiving element, a drive circuit 1220, and a control circuit unit 1230. Further, the spectroscopic measurement device 1200 includes an incident optical lens (not shown) that guides the inspection target light Lr, which is reflected light reflected by the inspection target B, at a position facing the optical filter 100.

  The light receiving unit 1210 includes a photoelectric exchange element (light receiving element), and generates an electrical signal corresponding to the amount of received light. The light receiving unit 1210 is connected to the control circuit unit 1230, and the generated electric signal is input to the control circuit unit 1230 as a light receiving signal. Note that the optical filter 100 and the light receiving unit 1210 can be unitized to form an optical filter module.

  The drive circuit 1220 is connected to the first electrode 40, the second electrode 60 (see FIG. 1), and the control circuit unit 1230 of the optical filter 100. The drive circuit 1220 applies a drive voltage between the first electrode 40 and the second electrode 60 based on the drive control signal input from the control circuit unit 1230, and causes the first reflective film 30 of the first substrate 10 to be applied. The diaphragm portion 10d is deformed so as to move to a predetermined displacement position. The drive voltage may be applied so that a desired potential difference is generated between the first electrode 40 and the second electrode 60. For example, a predetermined voltage is applied to the second electrode 60, and the first electrode 40 is applied. May be a ground potential. Note that a DC voltage is preferably used as the drive voltage.

  The control circuit unit 1230 controls the overall operation of the spectroscopic measurement device 1200, and includes a CPU 1231, a storage unit 1240, and the like. The CPU 1231 executes spectroscopic measurement processing based on various programs and various data stored in the storage unit 1240. The storage unit 1240 includes, for example, a RAM (Random Access Memory), a hard disk, or the like as a storage medium, and stores a program or data so as to be appropriately readable. The storage unit 1240 includes a voltage adjustment unit 1241, a gap measurement unit 1242, a light amount recognition unit 1243, and a measurement unit 1244. In addition, the storage unit 1240 stores voltage table data 1245 that associates the voltage values applied to the first electrode 40 and the second electrode 60 for adjusting the gap G shown in FIG. ing.

  The colorimetric control device 1300 is connected to the light source device 1100 and the spectroscopic measurement device 1200, and executes the colorimetry processing based on the control of the light source device 1100 and the spectral characteristics acquired by the spectroscopic measurement device 1200. As the color measurement control device 1300, for example, a general-purpose personal computer, a portable information terminal, a color measurement dedicated computer, other information processing equipment, or the like can be used. The color measurement control device 1300 includes a spectral characteristic acquisition unit 1310, a color measurement processing unit 1320, a light source control unit 1330, and the like.

  The spectral characteristic acquisition unit 1310 is connected to the spectroscopic measurement apparatus 1200 and acquires spectral characteristics input from the spectroscopic measurement apparatus 1200. The color measurement processing unit 1320 executes color measurement processing for measuring the chromaticity of the inspection target B based on the spectral characteristics acquired by the spectral characteristic acquisition unit 1310. The colorimetric processing is, for example, performing processing such as graphing the spectral characteristics acquired from the spectroscopic measurement device 1200 and displaying and displaying the spectral characteristics using a display or a printer (not shown). The light source control unit 1330 is connected to the light source device 1100, outputs a control signal to the light source device 1100 based on setting data input by an input unit (not shown), and emits predetermined emission light Ls from the light source device 1100.

  FIG. 7 is a flowchart showing the spectroscopic measurement operation of the colorimeter 1000 configured as described above. First, the CPU 1231 of the control circuit unit 1230 activates the voltage adjustment unit 1241, the light amount recognition unit 1243, and the measurement unit 1244. Further, the CPU 1231 initializes the measurement time variable n (sets n = 0) as an initial state (step S1). The measurement time variable n takes an integer value of 0 or more.

  Thereafter, the measurement unit 1244 measures the amount of light transmitted through the optical filter 100 in an initial state, that is, in a state where no voltage is applied to the first electrode 40 and the second electrode 60 of the optical filter 100 (step S1). S2). Note that the size of the gap G in the initial state may be measured in advance, for example, when the spectroscopic measurement apparatus is manufactured, and stored in the storage unit 1240. Then, the amount of transmitted light in the initial state obtained here and the size of the gap G are output to the colorimetric control device 1300.

  Next, the voltage adjustment unit 1241 reads the voltage table data 1245 stored in the storage unit 1240 (step S3). Further, the voltage adjustment unit 1241 adds “1” to the measurement time variable n (step S4).

  Thereafter, the voltage adjustment unit 1241 acquires voltage data and voltage application period data of the first electrode 40 and the second electrode 60 corresponding to the measurement time variable n from the voltage table data 1245 (step S5). Then, the voltage adjustment unit 1241 outputs a drive control signal to the drive circuit 1220, applies a voltage to the first electrode 40 and the second electrode 60 according to the data of the voltage table data 1245, and drives the optical filter 100. (Step S6).

  Further, the measurement unit 1244 performs the spectroscopic measurement process at the application time lapse timing (step S7). That is, the measurement unit 1244 causes the light amount recognition unit 1243 to measure the amount of transmitted light. In addition, the measurement unit 1244 performs control to output a spectroscopic measurement result that associates the measured amount of transmitted light and the wavelength of the transmitted light to the colorimetric control device 1300. In the measurement of the light quantity, the light quantity data of a plurality of times or all the times is stored in the storage unit 1240, and after obtaining the light quantity data for every plural times or the data of all the light quantities, the respective light quantities are collectively collected. May be measured.

  Thereafter, the CPU 1231 determines whether or not the measurement time variable n has reached the maximum value N (step S8). When the CPU 1231 determines that the measurement time variable n is N, the series of spectroscopic measurement operations are terminated. On the other hand, if the measurement time variable n is less than N in step S8, the process returns to step S4, a process of adding “1” to the measurement time variable n is performed, and the processes of step S5 to step S8 are repeated.

(Fourth embodiment)
FIG. 8 is a schematic diagram of a transmitter of a wavelength division multiplexing communication system, which is an example of an optical device according to the fourth embodiment, including the optical filters 100 and 110 according to the first embodiment or the optical filter 200 according to the second embodiment. It is a block diagram which shows a structure. In the description of the present embodiment, a transmitter including the optical filter 100 will be described. In wavelength division multiplexing (WDM) communication, using a characteristic that signals with different wavelengths do not interfere with each other, a plurality of optical signals with different wavelengths are used in a single optical fiber in a multiplexed manner. The amount of data transmission can be improved without increasing the number of lines.

  As shown in FIG. 8, the wavelength division multiplexing transmitter 2000 includes an optical filter 100 into which light from the light source 2100 is incident. The optical filter 100 transmits light having a plurality of wavelengths λ0, λ1, and λ2. Transmitters 2210, 2220, and 2230 are provided for each. The optical pulse signals for a plurality of channels from the transmitters 2210, 2220, and 2230 are combined into one by the wavelength multiplexing apparatus 2300 and sent to one optical fiber 2400 in the transmission path.

  The optical filters 100 and 110 according to the first embodiment or the optical filter 200 according to the second embodiment can be similarly applied to an optical code division multiplexing (OCDM) transmitter. In the OCDM, optical pulses constituting an optical pulse signal include optical components having different wavelengths, and channels are identified by pattern matching of the encoded optical pulse signal.

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

In the embodiment, the spectroscopic measurement device 1200 is exemplified as the electronic apparatus of the present invention. However, the optical filter driving method, the optical module, and the electronic apparatus of the present invention can be applied in various other fields. For example, it can be used as a light-based system for detecting the presence of a specific substance. As such a system, for example, an in-vehicle gas leak detector that detects a specific gas with high sensitivity by adopting a spectroscopic measurement method using the optical filter of the present invention, a photoacoustic rare gas detector for a breath test, etc. Examples of the gas detection device can be exemplified.
An example of such a gas detection device will be described below with reference to the drawings.

  FIG. 9 is a schematic diagram illustrating an example of a gas detection device including an optical filter. FIG. 10 is a block diagram showing a configuration of a control system of the gas detection device of FIG. As shown in FIG. 9, the gas detection device 3000 includes a sensor chip 3110, a flow path 3120 including a suction port 3120A, a suction flow path 3120B, a discharge flow path 3120C, and a discharge port 3120D, a main body 3130, It is configured with.

  The main body portion 3130 includes a sensor portion cover 3131 having an opening through which the flow path 3120 can be attached and detached, a discharge means 3133, a housing 3134, an optical portion 3135, a filter 3136, an optical filter 100, a light receiving element 3137 (detection portion), and the like. A detection device (optical module), a control unit 3138 (processing unit) that processes a detected signal and controls the detection unit, a power supply unit 3139 that supplies power, and the like are included. The optical unit 3135 emits light, and a beam splitter 3135B that reflects light incident from the light source 3135A toward the sensor chip 3110 and transmits light incident from the sensor chip toward the light receiving element 3137. And lenses 3135C, 3135D, and 3135E. As shown in FIG. 10, an operation panel 3140, a display unit 3141, a connection unit 3142 for interface with the outside, and a power supply unit 3139 are provided on the surface of the gas detection device 3000. When the power supply unit 3139 is a secondary battery, a connection unit 3143 for charging may be provided.

  Further, as shown in FIG. 10, the control unit 3138 of the gas detection device 3000 controls a signal processing unit 3144 configured by a CPU or the like, a light source driver circuit 3145 for controlling the light source 3135A, and the optical filter 100. A voltage control unit 3146, a light receiving circuit 3147 that receives a signal from the light receiving element 3137, and a sensor chip detection circuit 3149 that reads a code of the sensor chip 3110 and receives a signal from a sensor chip detector 3148 that detects the presence or absence of the sensor chip 3110. And a discharge driver circuit 3150 for controlling the discharge means 3133.

  Next, operation | movement of the above gas detection apparatuses 3000 is demonstrated below. A sensor chip detector 3148 is provided inside the sensor unit cover 3131 at the top of the main body unit 3130, and the sensor chip detector 3148 detects the presence or absence of the sensor chip 3110. When the signal processing unit 3144 detects the detection signal from the sensor chip detector 3148, the signal processing unit 3144 determines that the sensor chip 3110 is attached, and displays a display signal for displaying on the display unit 3141 that the detection operation can be performed. put out.

  For example, when the operation panel 3140 is operated by the user and an instruction signal to start the detection process is output from the operation panel 3140 to the signal processing unit 3144, first, the signal processing unit 3144 sends the light source driver circuit 3145 to the light source driver circuit 3145. A light source activation signal is output to activate the light source 3135A. When the light source 3135A is driven, laser light having a single wavelength and stable linear polarization is emitted from the light source 3135A. In addition, the light source 3135A includes a temperature sensor and a light amount sensor, and the information is output to the signal processing unit 3144. When the signal processing unit 3144 determines that the light source 3135A is operating stably based on the temperature and light quantity input from the light source 3135A, the signal processing unit 3144 controls the discharge driver circuit 3150 to operate the discharge unit 3133. Thereby, the gas sample containing the target substance (gas molecule) to be detected is guided from the suction port 3120A to the suction flow channel 3120B, the sensor chip 3110, the discharge flow channel 3120C, and the discharge port 3120D. Note that a dust removal filter 3120A1 is provided at the suction port 3120A to remove relatively large dust, some water vapor, and the like.

  In addition, the sensor chip 3110 is a sensor in which a plurality of metal nanostructures are incorporated and utilizing localized surface plasmon resonance. In such a sensor chip 3110, an enhanced electric field is formed between the metal nanostructures by laser light, and when gas molecules enter the enhanced electric field, Raman scattered light and Rayleigh scattered light including information on molecular vibrations are generated. Occur. These Rayleigh scattered light and Raman scattered light enter the filter 3136 through the optical unit 3135, and the Rayleigh scattered light is separated by the filter 3136, and the Raman scattered light enters the optical filter 100. Then, the signal processing unit 3144 outputs a control signal to the voltage control unit 3146. Thereby, the voltage control unit 3146 drives the optical filter 100 and causes the optical filter 100 to split the Raman scattered light corresponding to the gas molecules to be detected. Thereafter, when the dispersed light is received by the light receiving element 3137, a light reception signal corresponding to the amount of received light is output to the signal processing unit 3144 via the light receiving circuit 3147. In this case, target Raman scattered light can be extracted from the optical filter 100 with high accuracy. The signal processing unit 3144 compares the spectrum data of the Raman scattered light corresponding to the gas molecule to be detected obtained as described above with the data stored in the ROM, and determines whether or not the target gas molecule is the target gas molecule. To determine the substance. In addition, the signal processing unit 3144 causes the display unit 3141 to display the result information or outputs the result information from the connection unit 3142 to the outside.

  9 and 10 exemplify the gas detection device 3000 that performs gas detection from the Raman scattered light obtained by spectrally dividing the Raman scattered light with the optical filter 100. As the gas detection device, the gas-specific absorbance is used. It may be used as a gas detection device that identifies the gas type by detecting. In this case, a gas sensor that allows gas to flow into the sensor and detects light absorbed by the gas in the incident light is used as the optical module of the present invention. A gas detection device that analyzes and discriminates the gas flowing into the sensor by such a gas sensor is an electronic apparatus of the present invention. Even in such a configuration, it is possible to detect a gas component using an optical filter.

  In addition, the system for detecting the presence of a specific substance is not limited to the detection of the gas as described above, but a non-invasive measuring device for saccharides by near-infrared spectroscopy, and non-invasive information on food, living body, minerals, etc. A substance component analyzer such as a measuring device can be exemplified. Hereinafter, a food analyzer will be described as an example of the substance component analyzer.

  FIG. 11 is a diagram illustrating a schematic configuration of a food analyzer that is an example of an electronic apparatus using the optical filter 100. As shown in FIG. 11, the food analyzer 4000 includes a detector 4110 (optical module), a control unit 4120, and a display unit 4130. The detector 4110 detects a light source 4111 that emits light, an imaging lens 4112 into which light from a measurement object is introduced, an optical filter 100 that splits light introduced from the imaging lens 4112, and the dispersed light. An imaging unit 4113 (detection unit). The control unit 4120 also controls the light source control unit 4121 that controls turning on / off the light source 4111 and brightness control at the time of lighting, the voltage control unit 4122 that controls the optical filter 100, and the imaging unit 4113 to perform imaging. A detection control unit 4123 that acquires a spectral image captured by the unit 4113, a signal processing unit 4124, and a storage unit 4125.

  In the food analyzer 4000, when the system is driven, the light source 4111 is controlled by the light source control unit 4121, and the measurement object is irradiated with light from the light source 4111. Then, the light reflected by the measurement object enters the optical filter 100 through the imaging lens 4112. The optical filter 100 is driven by the driving method shown in the first embodiment under the control of the voltage controller 4122. Thereby, the light of the target wavelength can be extracted from the optical filter 100 with high accuracy. Then, the extracted light is imaged by an imaging unit 4113 configured by, for example, a CCD camera or the like. In addition, the captured light is accumulated in the storage unit 4125 as a spectral image. Further, the signal processing unit 4124 controls the voltage control unit 4122 to change the voltage value applied to the optical filter 100, and acquires a spectral image for each wavelength.

  Then, the signal processing unit 4124 performs arithmetic processing on the data of each pixel in each image accumulated in the storage unit 4125, and obtains a spectrum at each pixel. In addition, the storage unit 4125 stores, for example, information related to food components with respect to the spectrum, and the signal processing unit 4124 analyzes the obtained spectrum data based on the information related to food stored in the storage unit 4125. The food component contained in the detection target and its content are obtained. Moreover, a food calorie, a freshness, etc. are computable from the obtained food component and content. Furthermore, by analyzing the spectral distribution in the image, it is possible to extract a portion of the food to be inspected that has reduced freshness, and to detect foreign substances contained in the food. Can also be implemented. Then, the signal processing unit 4124 performs processing for causing the display unit 4130 to display information such as the components and contents of the food to be examined, the calories, and the freshness obtained as described above.

  Moreover, although the example of the food analysis apparatus 200 is shown in FIG. 11, it can utilize also as a noninvasive measurement apparatus of the other information as mentioned above by the substantially same structure. For example, it can be used as a biological analyzer for analyzing biological components such as measurement and analysis of body fluid components such as blood. As such a bioanalytical device, for example, a device that detects ethyl alcohol as a device that measures a body fluid component such as blood, it can be used as a drunk driving prevention device that detects the drunk state of the driver. Further, it can also be used as an electronic endoscope system provided with such a biological analyzer. Furthermore, it can also be used as a mineral analyzer for performing component analysis of minerals.

  Furthermore, the optical filter, optical module, and electronic apparatus of the present invention can be applied to the following devices. For example, by changing the intensity of light of each wavelength over time, it is possible to transmit data using light of each wavelength. In this case, light of a specific wavelength is dispersed by an optical filter provided in the optical module. By receiving light at the light receiving unit, data transmitted by light of a specific wavelength can be extracted, and light data of each wavelength is processed by an electronic device equipped with such an optical module for data extraction. Thus, optical communication can also be performed.

  In addition, the electronic apparatus can be applied to a spectroscopic camera, a spectroscopic analyzer, or the like that captures a spectroscopic image by dispersing light with the optical filter of the present invention. An example of such a spectroscopic camera is an infrared camera with a built-in optical filter. FIG. 12 is a schematic diagram showing a schematic configuration of the spectroscopic camera. As shown in FIG. 12, the spectroscopic camera 5000 includes a camera body 5100, an imaging lens unit 5200, and an imaging unit 5300 (detection unit). The camera body 5100 is a part that is gripped and operated by a user. The imaging lens unit 5200 is provided in the camera body 5100 and guides incident image light to the imaging unit 5300. The imaging lens unit 5200 includes an objective lens 5210, an imaging lens 5220, and an optical filter 100 provided between these lenses, as shown in FIG. The imaging unit 5300 includes a light receiving element, and images the image light guided by the imaging lens unit 5200.

  In such a spectroscopic camera 5000, a spectral image of light having a desired wavelength can be captured by transmitting light having a wavelength to be imaged by the optical filter 100. At this time, for each wavelength, the voltage control unit (not shown) drives the optical filter 100 by the driving method of the present invention as shown in the first embodiment, so that the spectral image of the target wavelength can be accurately obtained. Light can be extracted.

  Furthermore, the optical filter of the present invention may be used as a bandpass filter. For example, only light in a narrow band centered on a predetermined wavelength out of light in a predetermined wavelength range emitted from the light emitting element is spectrally separated by the optical filter. It can also be used as an optical laser device that transmits light. In addition, the optical filter of the present invention may be used as a biometric authentication device, and can be applied to authentication devices such as blood vessels, fingerprints, retinas, and irises that use light in the near infrared region and visible region.

  Furthermore, an optical module and an electronic device can be used as a concentration detection device. In this case, the infrared energy (infrared light) emitted from the substance is spectrally analyzed by the optical filter, and the analyte concentration in the sample is measured.

  As described above, the optical filter, the optical module, and the electronic device of the present invention can be applied to any device that separates predetermined light from incident light. And since the optical filter of this invention can disperse | distribute a some wavelength with one device as mentioned above, the measurement of the spectrum of a some wavelength and the detection with respect to a some component can be implemented accurately. Therefore, compared with the conventional apparatus which takes out a desired wavelength with a plurality of devices, it is possible to promote downsizing of the optical module and the electronic apparatus, and for example, it can be suitably used as a portable or in-vehicle optical device.

  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 10 ... 1st board | substrate, 20 ... 2nd board | substrate, 30 ... 1st reflective film, 40 ... 1st electrode, 50 ... 2nd reflective film, 60 ... 2nd electrode, 70 ... Aperture, 100 ... Optical filter.

Claims (8)

A first substrate having optical transparency and including a first reflective film on a first surface;
A second substrate disposed opposite to the first surface and having light transparency,
A surface of the second substrate opposite to the first surface is disposed along the outer periphery of the first recess and the first recess in a plan view as viewed from the thickness direction of the first substrate and the second substrate. A second concave portion that is circumferential in plan view is formed,
The distance between the first bottom portion constituting the bottom surface of the first recess and the second substrate is smaller than the distance between the second bottom portion constituting the bottom surface of the second recess and the second substrate,
A second reflective film is formed on the first bottom,
The second reflective film extends from the first bottom part to a surface connecting the first bottom part and the second bottom part,
A light filter characterized by that. The second reflective film is extended to the second bottom;
The optical filter according to claim 1. A first substrate having optical transparency and including a first reflective film on a first surface;
A second substrate disposed opposite to the first surface and having light transparency,
The surface of the second substrate facing the first surface is disposed on the outer surface of the first recess and the first recess in a plan view as viewed from the thickness direction of the first substrate and the second substrate. A second concave portion that is circumferential in view and a third concave portion inside the second concave portion outside the first concave portion in plan view,
The distance between the first bottom portion constituting the bottom surface of the first recess and the second substrate is smaller than the distance between the second bottom portion constituting the bottom surface of the second recess and the second substrate,
The distance from the third bottom portion constituting the bottom surface of the third recess is smaller than the distance between the second substrate and the third recess,
The second reflective film extends from the first bottom portion to the third bottom portion,
A light filter characterized by that. Electrodes are formed on the outer side of the first reflective film and on the second bottom of the first substrate.
The wavelength tunable filter according to any one of claims 1 to 3, wherein An antireflection film is formed on the first surface of the first substrate and the substrate surface formed by the first recess, the second recess, and the third recess of the second substrate,
The antireflection film is not formed on at least the surface of the first reflection film and the surface of the second reflection film formed on the first bottom,
The optical filter according to claim 3. The antireflection film is TiNx or TiOx (where x is an integer of 1 or more).
The optical filter according to claim 5. A first substrate having optical transparency and including a first reflective film on a first surface;
A second substrate disposed opposite to the first surface and having optical transparency;
A housing,
A surface of the second substrate opposite to the first surface is disposed along the outer periphery of the first recess and the first recess in a plan view as viewed from the thickness direction of the first substrate and the second substrate. A second concave portion that is circumferential in plan view is formed,
The distance between the first bottom portion constituting the bottom surface of the first recess and the second substrate is smaller than the distance between the second bottom portion constituting the bottom surface of the second recess and the second substrate,
A second reflective film is formed on the first bottom,
The second reflective film extends from the first bottom part to a surface connecting the first bottom part and the second bottom part,
An optical filter device characterized by that.   An optical device comprising the optical filter according to any one of claims 1 to 6.

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