JP2011191474A - Wavelength variable interference filter, colorimetric sensor, colorimetric module, and method of manufacturing the wavelength variable interference filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength variable interference filter having a large spectral wavelength region and high transmittance and resolution of dispersed light, a colorimetric sensor, and a colorimetric module. <P>SOLUTION: An etalon includes a pair of mirrors 56 and 57 facing each other and an electrostatic actuator for varying the gap between mirrors which is the interval between these mirrors. Each of the pair of mirrors 56 and 57 includes a plurality of dielectric films 551, and post members 552 that are disposed between these dielectric films 551, keeps the distance between the dielectric films 551 facing each other at a predetermined dimension, and forms an air layer 553 between the dielectric films 551 facing each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wavelength variable interference filter that selects and emits light having a desired target wavelength from incident light, a colorimetric sensor including the wavelength variable interference filter, a colorimetric module including the colorimetric sensor, and a wavelength variable The present invention relates to a method for manufacturing an interference filter.

  Conventionally, a spectral filter that acquires only light of a specific wavelength from incident light by reflecting light between a pair of mirrors, transmitting only light of a specific wavelength, and canceling light of other wavelengths by interference is known. It has been. As such a spectral filter, there is known a wavelength variable interference filter that selects and emits light to be emitted by adjusting the distance between mirrors (see, for example, Patent Document 1).

In the optical device (wavelength variable interference filter) described in Patent Document 1, a plate-like first structure and a second structure having optical transparency are arranged to face each other, and the first structure and the second structure are arranged. A first reflection film (mirror) and a second reflection film (mirror) are formed on the surfaces of the body facing each other. A first drive electrode and a second drive electrode are formed between the first structure body and the second structure body, respectively. By applying a voltage between these drive electrodes, The gap between the first reflective film and the second reflective film is varied. The first reflective film and the second reflective film include, for example, a high refractive index layer made of Ti ₂ O, Ta ₂ O _2, and a low refractive index layer made of MgF ₂ , SiO _2, etc. A dielectric multilayer film in which are alternately stacked is used.

JP 2008-116669 A

  By the way, as a wavelength variable interference filter, for example, light can be dispersed in a wide wavelength range such as the entire visible light range, the transmittance of the dispersed light is high, and the half-value width is narrow (resolution is low). High). Such spectral characteristics vary depending on the configuration of the first and second reflective films (mirrors). Here, when these reflective films are composed of, for example, a single layer of AgC, it is possible to cover the entire visible light range as a spectral range that can be dispersed, but the transmittance of the dispersed light is poor and the half-value width is also small. There is a problem of widening.

On the other hand, as described in Patent Document 1, a dielectric multilayer in which a high refractive index layer and a low refractive index layer are alternately stacked as the first reflective film and the second reflective film constituting the wavelength variable interference filter. When a film is used, the light transmittance and resolution of the wavelength variable interference filter can be improved. However, since a solid layer composed of MgF ₂ , SiO ₂ or the like is used as the low refractive index layer of the dielectric multilayer film, the difference in refractive index between the high refractive index layer and the low refractive index layer is small, and the dielectric The wavelength range of light reflected by the multilayer film is also narrowed. For this reason, the wavelength range which can be spectrally separated by the wavelength tunable interference filter becomes narrow, and there is a problem that a wide wavelength range such as the entire visible light cannot be covered.

  In the present invention, in view of the problems as described above, a wavelength variable interference filter, a colorimetric sensor, a colorimetric module, and a wavelength tunable filter having a wide spectral range that can be dispersed and a high transmittance and resolution of the dispersed light. An object of the present invention is to provide a method for manufacturing an interference filter.

  The wavelength tunable interference filter of the present invention includes a pair of mirrors facing each other and variable means for varying the distance between the mirrors. The mirror includes a plurality of dielectric films and a gap between these dielectric films. And a post member for holding a space between the dielectric films facing each other in parallel and forming a space between the dielectric films.

In the present invention, a post member is provided between a plurality of dielectric films constituting the mirror, and a gap is formed between the dielectric films facing each other by the post member. A space (low refractive space) formed by small air is formed.
The mirror having such a configuration is a laminated mirror having a dielectric film as a high refractive index layer and a low refractive space as a low refractive index layer. Here, in a mirror in which a low refractive space is interposed between dielectric films, the difference in refractive index between each layer is larger than in a laminated mirror in which a dielectric film and a solid low refractive index layer are laminated. The reflectivity increases and the wavelength range of light that can be reflected is also widened. In addition, when the wavelength range that can be reflected by the mirror is widened, light in a wider wavelength range can be reflected between the pair of mirrors of the wavelength tunable interference filter, and these wide wavelengths can be adjusted by adjusting the gap between the mirrors. Only light having a desired wavelength can be dispersed and transmitted from the light in the region. That is, the wavelength range of light that can be dispersed by the wavelength variable interference filter is expanded.
In addition, since the reflectivity of each mirror also increases, the light that is not spectrally separated by the wavelength variable interference filter is reduced compared to the case of using a normal dielectric multilayer mirror in which a dielectric film and a solid low refractive index layer are stacked. Thus, it is possible to more reliably reflect the light with a mirror. That is, in the variable wavelength interference filter, the amount of transmission of light other than the desired wavelength is reduced, and the resolution can be further improved.

In addition, as a configuration in which an air layer is interposed between the dielectric films, for example, a configuration in which the outer peripheral edge of the dielectric film is held by a cylindrical frame member may be considered. In such a configuration, The center part is bent, and it becomes difficult to maintain a pair of mirrors facing each other in parallel. In such a case, the gap between the pair of mirrors (gap between the mirrors) varies depending on the mirror position, and the light transmittance and resolution are reduced. On the other hand, in the present invention, since the post member is provided between the dielectric films, the central portion of the dielectric film is not bent and each dielectric film can be kept parallel. Accordingly, the pair of mirrors facing each other is also kept parallel, and the light transmittance and resolution of the wavelength tunable interference filter due to the bending of the dielectric film can be prevented.
As described above, in the wavelength tunable interference filter of the present invention, when a single-layer mirror is provided, or when a mirror having an air layer interposed between a reflective film held by a cylindrical frame member is provided, a high refractive index dielectric Compared to the case of providing a dielectric multilayer mirror with a solid low refractive index layer interposed between the films, the transmittance and resolution of the dispersed light can be improved, and the spectral wavelength range can be expanded. be able to. That is, the wavelength tunable interference filter of the present invention can achieve both high transmittance and high resolution of the light to be spectrally dispersed and widening of the wavelength range in which spectroscopy is possible.

  In the wavelength tunable interference filter of the present invention, the post member is a transparent member, and the ratio of the area occupied by the post member to the total area of the mirror in a plan view of the mirror is 20% or less. Is preferred.

When the post member has translucency, at the position where the post member is not provided in the mirror, it becomes a mirror structure (high reflection structure) in which low refractive spaces composed of air or the like and dielectric films are alternately laminated, At the position where the post member is provided, a mirror structure (low reflection structure) in which the dielectric film and the post member are stacked is formed. In the variable wavelength interference filter, in the configuration in which the high reflection structure and the low reflection structure as described above are mixed in one mirror, the mirror reflection characteristics of these high reflection structure and low reflection structure are different. Different spectral characteristics. Here, when the area occupied by the post member is larger than 20%, the transmission amount of the light split by the low reflection structure portion increases, and the half width of the transmittance of the split light is increased in the entire wavelength variable interference filter. It becomes wider and the resolution decreases. On the other hand, when the post member is transparent as in the present invention, the proportion of the post member is set to 20% or less with respect to the total area of the mirror, so that the amount of light transmitted through the low reflection structure portion is reduced. As a result, the amount of light transmitted through the highly reflective structure portion increases, and a reduction in resolution can be suppressed.
In addition, the minimum value of the area occupied by the post member with respect to the total area of the mirror is only required to have an area necessary for preventing the dielectric film from being bent. The specific value is appropriately set depending on the thickness dimension of the dielectric film, the area where each post member holds the dielectric film (cross-sectional area of the post member), the shape of the post member, etc. It suffices if it is formed at 2% or more of the total area of the mirror.

  In the wavelength tunable interference filter of the present invention, the post member is an opaque member, and the ratio of the area occupied by the post member to the total area of the mirror in a plan view of the mirror is 50% or less. It is good.

As the post member, a non-translucent material can be used. In this case, the ratio of the area occupied by the post member to the mirror area is set to 50% or less.
Here, when a post member that is an opaque member is used, if the proportion of the post member is large, the light dispersed by the wavelength variable interference filter is blocked by the post member, so that the transmittance is deteriorated and the proportion of the post member is 50. When the ratio is larger than%, the amount of light transmitted through the wavelength tunable interference filter is significantly reduced. In such a wavelength variable interference filter with poor light transmittance, for example, when measuring the amount of transmitted light and performing colorimetric processing of an inspection object, it is not possible to measure the exact amount of light of each wavelength component. There is also a possibility that the measurement accuracy is lowered. On the other hand, as in the present invention, by setting the ratio of the post member to 50% or less, it is possible to suppress the deterioration of the transmittance of the wavelength tunable interference filter to the extent that the measurement accuracy does not decrease.
Further, in the configuration in which the post member is opaque, the portion where the post member is provided does not transmit light. Therefore, unlike the above-described invention, the resolution of the wavelength variable interference filter is not reduced by the low reflection structure portion, and the translucent member Compared with the case where the post member is provided, the resolution of the variable wavelength interference filter can be improved.
Further, as the minimum value of the area occupied by the post member with respect to the total area of the mirror, it is only necessary to have an area necessary for preventing the dielectric film from being bent, as in the above-described invention. The specific value is appropriately set depending on the thickness dimension of the dielectric film, the area where each post member holds the dielectric film (cross-sectional area of the post member), the shape of the post member, etc. It suffices if it is formed at 2% or more of the total area of the mirror.

  In the wavelength tunable interference filter according to the aspect of the invention, it is preferable that the post member has a minimum cross-sectional dimension of 100 μm or less when the post member is sectioned along a plane parallel to the mirror surface.

Here, the minimum value of the cross-sectional dimension of the post member indicates, for example, the short-axis dimension when the post member has an elliptical cross-section, and the short-side dimension when the post member has a rectangular cross-sectional shape. When the post member has a circular cross section, it indicates the diameter dimension. That is, the post member is formed to have a dimension of 100 μm or less at a portion where the dimension is the shortest in the cross-sectional shape.
When the minimum value of the cross-sectional dimension of the post member is larger than 100 μm, when the post member is transparent, the area of the low-reflective structure increases, so the resolution is lowered, and when the post member is opaque, the amount of transmitted light Will decrease.
On the other hand, when the minimum value of the cross-sectional dimension in the cross-sectional shape of the post member is 100 μm or less, the light transmission inhibition amount by the post member can be reduced, and the resolution of the etalon and the transmittance are reduced. Can be suppressed.
In addition, the lower limit of the minimum value of the cross-sectional dimension of the post member is set as appropriate depending on the rigidity of the material forming the post member, and there is no distortion or deflection of the dielectric film due to the inclination of the post member. It suffices if the cross sectional dimension is formed.

In the wavelength variable interference filter according to the aspect of the invention, it is preferable that the space is a vacuum layer.
In the present invention, since the low refractive space between the dielectric films facing each other is a vacuum layer having a light refractive index smaller than that of air, the reflectance is reduced as compared with the case where an air layer is formed between the dielectric films. This can be further improved, and the wavelength range that can be reflected can be further expanded. Therefore, the transmittance and resolution of the dispersed light of the wavelength tunable interference filter can be further improved, and the spectral wavelength range can be further expanded.
In addition, when the space between the dielectric films is a vacuum, even when the mirror is moved by the variable means, no resistance is applied to the dielectric film. Therefore, even when the moving speed of the mirror is increased, it is possible to prevent the dielectric film from being bent when the mirror is moved.

On the other hand, in the wavelength tunable interference filter of the present invention, the space may be a gas layer.
Here, the gas layer may be a gas that does not absorb light in the wavelength band in which the wavelength tunable interference filter is to be transmitted. For example, in the wavelength tunable interference filter, the predetermined wavelength in the visible light region is spectrally transmitted. In this case, an air layer, a helium layer, or the like can be used as the gas layer.
In the present invention, it is not necessary to manufacture the mirror in a vacuum state or to store the mirror in a vacuum package at the time of manufacturing the mirror, so that the mirror can be easily manufactured. In addition, when there is gas between the dielectric films, resistance is applied to the dielectric film by displacing the mirror, but the deflection of the dielectric film due to gas resistance is controlled by controlling the mirror movement speed and reducing the movement speed. Can be prevented.

In the variable wavelength interference filter according to the aspect of the invention, it is preferable that the dielectric film of the mirror is formed of titanium oxide.
The plurality of dielectric films constituting the mirror preferably have a high refractive index in order to increase the difference in refractive index from the inter-film space. For example, titanium oxide or tantalum oxide can be used. . Among these, by using titanium oxide having a particularly high refractive index and low wavelength absorption, the reflectance of the mirror can be improved, and the wavelength range of light that can be reflected can be widened.

  A colorimetric sensor according to the present invention includes the above-described wavelength tunable interference filter and light receiving means for receiving light transmitted through the wavelength tunable interference filter.

In this invention, the colorimetric sensor includes the wavelength variable interference filter of the invention described above. Therefore, the wavelength tunable interference filter of the present invention has a wavelength that can be spectrally compared with a conventional dielectric multilayer mirror in which a dielectric film and a solid low refractive index layer are laminated, or a filter using a single layer mirror. The area can be widened, and the transmittance and resolution of the dispersed light can be improved.
In the colorimetric sensor, the light separated by such a wavelength variable interference filter is received by the light receiving means. Therefore, in the colorimetric sensor of the present invention, for example, as a filter, a wavelength variable interference filter using a mirror in which a solid high-refractive index layer and a solid low-refractive index layer are stacked is incorporated. The amount of light can be measured. In addition, the colorimetric sensor of the present invention can split incident light with high transmittance and high resolution compared to a case where a wavelength variable interference filter using, for example, an AgC single layer mirror is incorporated. The intensity of light having a wavelength can be measured with higher accuracy.

  The color measurement module of the present invention includes the above-described color measurement sensor and a color measurement processing unit that performs color measurement processing based on light received by the light receiving unit of the color measurement sensor. And

  In the present invention, similarly to the above-described invention, a colorimetric sensor is used because a wavelength variable interference filter including a mirror in which a dielectric film as a high refractive index layer and a low refractive space formed by a post member are stacked is used. With this light receiving means, it is possible to split the inspection target light into light having a wide range of wavelengths and accurately detect the amount of light of each of the split wavelengths. Therefore, also in the processing means, the intensity of each color component constituting the inspection target light can be accurately analyzed based on these light quantities.

  The method for producing a wavelength tunable interference filter according to the present invention includes a laminating step of forming a laminated body in which the dielectric film and a sacrificial layer that is a material for forming the post member are alternately laminated on a substrate; A hole forming step of forming a plurality of holes penetrating from the upper surface to the substrate surface, and a post for forming the post member by etching the sacrificial layer in a predetermined range centering on the hole and remaining the sacrificial layer And a forming step.

In the wavelength tunable interference filter manufacturing method of the present invention, first, a laminated body of a sacrificial layer and a dielectric film is formed on a substrate by a laminating process, and a plurality of holes are formed in the laminated body in the hole forming process. . Then, in the post member forming step, a part of the sacrificial layer is removed by etching the sacrificial layer around the hole. As a result, the etched portion of the sacrificial layer becomes a low refraction space formed by air or the like, and the unetched portion remains and becomes a post member that holds between the opposing dielectric films.
In such a manufacturing method, it is necessary to provide a hole in the mirror. For example, the low refractive space and the post member can be easily formed simply by injecting an etching fluid into the formed hole.

  As a method of manufacturing the wavelength tunable interference filter of the present invention, a lamination process of alternately laminating the dielectric film and a sacrificial layer that can be removed by etching on a substrate, and a top surface of the laminate A hole forming step of forming a plurality of holes penetrating to the substrate surface; a post member embedding step of embedding the post member in the hole; and a sacrificial layer removing step of etching and removing the sacrificial layer. It is good also as a manufacturing method provided.

In the present invention, in forming the mirror of the wavelength tunable interference filter, first, in the laminating process, a laminated body in which the dielectric film and the sacrificial layer are laminated is formed, and in the hole forming process, holes are formed in the laminated body. Then, the post member is formed by embedding the post member in the hole, and thereafter, all the sacrificial layers are removed by etching.
When a wavelength tunable interference filter is manufactured by such manufacturing, it is necessary not only to form a hole but also to embed a post member, which complicates the manufacturing process, but the post member can be freely selected. That is, in the invention in which the post member is formed by etching the sacrificial layer described above, the manufacture of the mirror is simplified, but it is necessary to use a material that can be etched as the post member. Various materials may be used, and the range of selection of the post member is increased.
Furthermore, when the post member is formed by etching, the thickness of the post member may become non-uniform, for example, the cross-sectional dimension of the central portion of the post member is small and the cross-sectional dimension of both end portions in contact with the dielectric film is large. In contrast, it is difficult to control the etching, but in the present invention, a rod-shaped post member having a uniform thickness can be embedded in the hole. By using such a post member having a uniform thickness, the holding force for holding the dielectric film is increased, and the dielectric film is not easily deformed by external stress, for example, resistance when the mirror is moved. It is possible to prevent the body membrane from being bent or inclined.

  Further, the method of manufacturing a wavelength tunable interference filter according to the present invention includes a sacrificial layer forming step of forming a sacrificial layer provided with a hole for forming a post member, and covering the sacrificial layer, and in the hole and the sacrificial layer. A dielectric layer forming step of forming a dielectric layer on the surface of the substrate multiple times to form a laminate in which a plurality of the sacrificial layers and the dielectric layers are laminated on the substrate, and the sacrifice And a sacrificial layer removing step of removing the layer by an etching process.

In the present invention, in the stacking step, a sacrificial layer having a hole for forming a post member is formed in the sacrificial layer forming step, and a dielectric film is stacked on the surface and in the hole in the dielectric layer forming step, and then sacrificed again. By performing the layer forming step, a sacrificial layer having a hole for forming a post member is formed on the surface of the dielectric film. This is repeated for the number of laminated dielectric films constituting the mirror to form a laminated body. Thereafter, in the sacrificial layer removing step, only the sacrificial layer is removed by etching from these stacked bodies.
In such a manufacturing method, a mirror can be formed by simply removing the sacrificial layer in the sacrificial layer removing step on the stacked body formed by laminating in the laminating step. Therefore, precise etching control for forming holes, embedding the post members, and forming the post members is unnecessary, and the manufacture of the variable wavelength interference filter is further facilitated. Further, since the sacrificial layer corresponding to the low refractive space between the dielectric films is formed and the sacrificial layer is removed after the stacked body is formed, the cross-sectional dimension of the post member can be made uniform. Accordingly, as in the case of the above-described invention, the holding force of the dielectric film by the post member is increased, and the deflection and inclination of the dielectric film can be prevented.

It is a figure which shows schematic structure of the color measurement module of 1st embodiment which concerns on this invention. It is a top view which shows schematic structure of the etalon which comprises the wavelength variable interference filter of 1st embodiment. It is sectional drawing which shows schematic structure of the etalon of 1st embodiment. It is sectional drawing which shows schematic structure of each mirror of 1st embodiment. FIG. 5 is a cross-sectional view illustrating a schematic configuration of a low refraction space taken along line VV in FIG. It is a figure which shows the manufacturing process of an etalon, (A) is the schematic of each board | substrate in a board | substrate formation process, (B) is the schematic of each board | substrate in a mirror formation process, (C) is each figure in an electrode formation process FIG. 4D is a schematic diagram of a substrate, and FIG. 4D is a diagram illustrating a schematic diagram of an etalon formed after a bonding process and a diaphragm forming process. It is a figure which shows the lamination process in the mirror formation process of the etalon of 1st embodiment. . It is a figure which shows the hole formation process in the mirror formation process of 1st embodiment, (A) is sectional drawing which shows the outline of the mirror after a hole formation process, (B) is a figure of the hole formed by a hole formation process. It is a figure which shows the example of a position. It is sectional drawing which shows schematic structure of the mirror of 2nd embodiment. It is a figure which shows the mirror formation process of 2nd embodiment, (A) is a lamination process, (B) is a hole formation process, (C) is a figure which shows a post | mailbox embedding process. It is a figure which shows schematic structure of the mirror in the etalon 5 of 3rd embodiment. It is a figure which shows the lamination | stacking process in the mirror formation process of 3rd embodiment, (A) is the 1st sacrificial layer formation process which forms the lowermost sacrificial layer, (B) is the lowermost dielectric film and post | mailbox A first dielectric layer forming step of forming a member; (C) a second sacrificial layer forming step of forming a sacrificial layer on the dielectric film; and (D) a dielectric on the dielectric film and the sacrificial layer. It is a figure which shows the 2nd dielectric material layer formation process which forms a film | membrane. It is an example of the shape of the sacrificial layer in 3rd embodiment, and is a top view of the sacrificial layer in the case of forming in net shape. It is a figure which shows the structure of the etalon 5 of 4th embodiment. It is a figure which shows the shape of the post member and hole in other embodiment. It is a figure which shows the shape of the post member and hole in other embodiment.

[First embodiment]
Hereinafter, a color measurement module according to a first embodiment of the present invention will be described with reference to the drawings.
[1. Overall configuration of the color measurement module)
FIG. 1 is a diagram showing a schematic configuration of a color measurement module according to the first embodiment of the present invention.
As shown in FIG. 1, the color measurement module 1 includes a light source device 2 that emits light to an inspection target A, a color measurement sensor 3 according to the present invention, and a control device 4 that controls the overall operation of the color measurement module 1. And. The color measurement module 1 reflects the light emitted from the light source device 2 by the inspection target A, receives the reflected inspection target light by the color measurement sensor, and outputs the light from the color measurement sensor 3. This module analyzes and measures the chromaticity of the inspection target light, that is, the color of the inspection target A based on the detection signal.

[2. Configuration of light source device]
The light source device 2 includes a light source 21 and a plurality of lenses 22 (only one is shown in FIG. 1), and emits white light to the inspection target A. The plurality of lenses 22 include a collimator lens, and the light source device 2 converts the white light emitted from the light source 21 into parallel light by the collimator lens, and passes from the projection lens (not shown) to the object A to be inspected. Ejected towards.

[3. (Configuration of colorimetric sensor)
As shown in FIG. 1, the colorimetric sensor 3 transmits the etalon 5 constituting the wavelength tunable interference filter of the present invention, a light receiving element 31 as a light receiving means for receiving light transmitted through the etalon 5, and the etalon 5. Voltage control means 6 for changing the wavelength of light. Further, the colorimetric sensor 3 includes an incident optical lens (not shown) that guides reflected light (inspection target light) reflected by the inspection target A at a position facing the etalon 5. The colorimetric sensor 3 uses the etalon 5 to split only the light having a predetermined wavelength out of the inspection target light incident from the incident optical lens, and the light receiving element 31 receives the split light.
The light receiving element 31 includes a plurality of photoelectric exchange elements, and generates an electrical signal corresponding to the amount of received light. The light receiving element 31 is connected to the control device 4 and outputs the generated electrical signal to the control device 4 as a light reception signal.

(3-1. Composition of etalon)
FIG. 2 is a plan view showing a schematic configuration of the etalon 5 constituting the tunable interference filter of the present invention, and FIG. 3 is a cross-sectional view showing a schematic configuration of the etalon 5. In FIG. 1, the inspection target light is incident on the etalon 5 from the lower side in the figure, but in FIG. 3, the inspection target light is incident from the upper side in the figure.
As shown in FIG. 2, the etalon 5 is a planar square plate-shaped optical member, and one side is formed to be 10 mm, for example. The etalon 5 includes a first substrate 51 and a second substrate 52 as shown in FIG. These two substrates 51 and 52 are each formed of, for example, various glasses such as soda glass, crystalline glass, quartz glass, lead glass, potassium glass, borosilicate glass, and alkali-free glass, or crystal. . Among these, as a constituent material of each board | substrate 51 and 52, the glass containing alkali metals, such as sodium (Na) and potassium (K), for example is preferable, and by forming the board | substrates 51 and 52 with such glass, Thus, it becomes possible to improve the adhesion between the mirrors 56 and 57, which will be described later, and the electrodes, and the bonding strength between the substrates. And these two board | substrates 51 and 52 are comprised integrally by joining the joint surfaces 513 and 524 formed in the outer peripheral part vicinity.

Further, between the first substrate 51 and the second substrate 52, a fixed mirror 56 and a movable mirror 57 constituting a pair of mirrors of the present invention are provided. Here, the fixed mirror 56 is fixed to the surface of the first substrate 51 facing the second substrate 52, and the movable mirror 57 is fixed to the surface of the second substrate 52 facing the first substrate 51. Further, the fixed mirror 56 and the movable mirror 57 are disposed to face each other with a gap G between the mirrors.
Furthermore, an electrostatic actuator 54 for adjusting the dimension of the inter-mirror gap G between the fixed mirror 56 and the movable mirror 57 is provided between the first substrate 51 and the second substrate 52.

(3-1-1. Configuration of the first substrate)
The first substrate 51 is formed by processing a glass substrate having a thickness of, for example, 500 μm by etching. Specifically, as shown in FIG. 3, an electrode forming groove 511 and a mirror fixing groove 512 are formed on the first substrate 51 by etching.
The electrode formation groove 511 is formed in a circular shape centered on the plane center point in a plan view of the etalon 5 as shown in FIG. The mirror fixing groove 512 is concentric with the electrode forming groove 511 in a plan view and is formed in a circular shape having a smaller diameter than the electrode forming groove 511.
In the electrode forming groove 511, a ring-shaped electrode fixing surface 511A is formed between the outer peripheral edge of the mirror fixing groove 512 and the inner peripheral wall surface of the electrode forming groove 511, and the electrode fixing surface 511A is used for the first displacement. An electrode 541 is formed. Further, from a part of the outer peripheral edge of the first displacement electrode 541, the first displacement electrode lead portion 541A extends toward the lower left direction and the upper right direction of the etalon in a plan view as shown in FIG. Is formed. Further, first displacement electrode pads 541B are respectively formed at the tips of the first displacement electrode lead portions 541A, and these first displacement electrode pads 541B are connected to the voltage control means 6.
Here, when the electrostatic actuator 54 is driven, a voltage is applied to only one of the pair of first displacement electrode pads 541B by the voltage control means 6. The other first displacement electrode pad 541B is used as a detection terminal for detecting the charge retention amount of the first displacement electrode 541.

  As described above, the mirror fixing groove 512 is coaxial with the electrode forming groove 511 and has a smaller diameter than the electrode forming groove 511. In the present embodiment, as shown in FIG. 3, an example in which the depth dimension of the mirror fixing groove 512 is formed deeper than the depth dimension of the electrode forming groove 511 is shown. Dimension of gap G between mirrors between fixed mirror 56 fixed to the bottom surface (mirror fixing surface 512A) and movable mirror 57 formed on second substrate 52, formed on first displacement electrode 541 and second substrate 52 The thickness is appropriately set according to the dimension between the second displacement electrodes 542 described later and the thickness dimension of the fixed mirror 56 and the movable mirror 57.

  Further, it is preferable that the mirror fixing groove 512 is designed with a groove depth in consideration of a wavelength range through which the etalon 5 is transmitted. For example, in this embodiment, the initial value of the inter-mirror gap G between the fixed mirror 56 and the movable mirror 57 (between the mirrors in a state where no voltage is applied between the first displacement electrode 541 and the second displacement electrode 542). The dimension of the gap G) is set to 450 nm, and by applying a voltage between the first displacement electrode 541 and the second displacement electrode 542, the movable mirror 57 can be displaced until the inter-mirror gap G reaches 250 nm. Thus, by varying the voltage between the first displacement electrode 541 and the second displacement electrode 542, it is possible to selectively disperse and transmit light having a wavelength in the entire visible light range. It becomes. In this case, the film thickness of the fixed mirror 56 and the movable mirror 57, the depth dimension of the mirror fixing groove 512, and the depth dimension of the electrode forming groove 511 are set so that the gap G between the mirrors can be displaced between 250 nm and 450 nm. Yes.

  A fixed mirror 56 formed in a circular shape having a diameter of about 3 mm is fixed to the mirror fixing surface 512A. A detailed description of the fixed mirror 56 will be described later.

  Furthermore, the first substrate 51 is provided with an antireflection film (AR) (not shown) at a position corresponding to the fixed mirror 56 on the lower surface opposite to the upper surface facing the second substrate 52. This antireflection film is formed by alternately laminating low refractive index films and high refractive index films, and reduces the reflectance of visible light on the surface of the first substrate 51 and increases the transmittance.

(3-1-2. Configuration of Second Substrate)
The second substrate 52 is formed by processing a glass substrate having a thickness of, for example, 200 μm by etching.
Specifically, the second substrate 52 has a circular movable portion 521 centered on the substrate center point and a connection that is coaxial with the movable portion 521 and holds the movable portion 521 in a plan view as shown in FIG. Holding part 522.

  The movable portion 521 is formed to have a thickness dimension larger than that of the connection holding portion 522. For example, in the present embodiment, the movable portion 521 is formed to be 200 μm, which is the same as the thickness dimension of the second substrate 52. The movable part 521 includes a movable surface 521A parallel to the mirror fixing groove 512, and the movable mirror 57 is fixed to the movable surface 521A. Here, the movable mirror 57 and the fixed mirror 56 described above constitute a pair of mirrors of the present invention. In the present embodiment, the inter-mirror gap G between the movable mirror 57 and the fixed mirror 56 is set to 450 nm in the initial state. A detailed description of the configuration of the movable mirror 57 will be given later.

  Further, the movable portion 521 has an antireflection film (AR) (not shown) formed at a position corresponding to the movable mirror 57 on the upper surface opposite to the movable surface 521A. This antireflection film has the same configuration as the antireflection film formed on the first substrate 51, and is formed by alternately laminating a low refractive index film and a high refractive index film.

The connection holding part 522 is a diaphragm surrounding the periphery of the movable part 521, and has a thickness dimension of, for example, 50 μm. A ring-shaped second displacement electrode 542 facing the first displacement electrode 541 with an electromagnetic gap of about 1 μm is formed on the surface of the connection holding portion 522 facing the first substrate 51. . Here, the second displacement electrode 542 and the first displacement electrode 541 described above constitute an electrostatic actuator 54 which is a variable means of the present invention.
Also, a pair of second displacement electrode lead portions 542A are formed from the part of the outer peripheral edge of the second displacement electrode 542 toward the outer peripheral direction, and at the tip of these second displacement electrode lead portions 542A A second displacement electrode pad 542B is formed. More specifically, the second displacement electrode lead portion 542A extends toward the lower right and upper left directions of the etalon in a plan view as shown in FIG. It is formed point-symmetrically.
Similarly to the first displacement electrode pad 541B, the second displacement electrode pad 542B is connected to the voltage control means 6, and when the electrostatic actuator 54 is driven, of the pair of second displacement electrode pads 542B. A voltage is applied to only one of them. The other second displacement electrode pad 542B is used as a detection terminal for detecting the charge retention amount of the second displacement electrode 542.

(3-1-3. Configuration of mirror)
Next, the configuration of the fixed mirror 56 and the movable mirror 57 which are a pair of mirrors of the present invention will be described with reference to the drawings. FIG. 4 is a cross-sectional view showing a schematic configuration of the mirrors 56 and 57 of the present embodiment, and FIG. 5 is a cross-sectional view showing a schematic configuration of a low refraction space taken along the line VV in FIG. 4 and 5, the dimensions of the post member 552 and the hole 554 and the dimension between the dielectric films 551 are displayed larger than actual for easy understanding, but in actuality, they are sufficiently small relative to the mirror. Is formed.

  As shown in FIG. 4, the mirrors 56 and 57 (the fixed mirror 56 and the movable mirror 57) are configured by laminating a plurality of dielectric films 551 with a post member 552 interposed therebetween. That is, between the dielectric films 551 stacked in the thickness direction, spaces corresponding to the height dimension of the post members 552 (low refractive spaces) are formed. Here, in the present invention, the low refractive space means a space having a refractive index smaller than that of a solid low refractive index layer generally used for a dielectric multilayer mirror, for example, in the present embodiment, for example. The low refractive space is an air layer 553. A multilayer mirror is configured by laminating a high refractive index layer composed of a dielectric film 551 having a high refractive index and an air layer 553. The number of laminated dielectric films 551 is not particularly limited. In this embodiment, the number of dielectric films 551 and the number of air layers 553 is 16 layers. In this embodiment, the fixed mirror 56 and the movable mirror 57 are configured by the same number of dielectric films 551 and air layers 553. However, the fixed mirror 56 and the movable mirror 57 have different numbers of layers. It is good.

As the dielectric film 551, for example, a high refractive index material such as titanium oxide (TiO ₂ ) or tantalum oxide (Ta ₂ O ₃ ) can be used. Among these high refractive materials, it is more preferable to use TiO ₂ that has a particularly high refractive index and has a light absorption rate of a specific wavelength that is smaller than that of others.
The film thickness of the dielectric film 551 is set to ¼ of the center wavelength of the light reflected by the mirrors 56 and 57, and in this embodiment, is ¼ of 600 nm which is the center wavelength of the visible light region. It is formed to 125 nm.
Note that the etalon 5 of the present embodiment targets the visible light region (for example, 360 nm to 800 nm) in a wavelength region that can be dispersed, and the mirrors 56 and 57 need to reflect the light in the visible light region. The film thickness of the body film 551 should just be formed in 90 nm-200 nm. However, for example, when the film thickness is formed in the vicinity of 90 nm, the reflectance of the high wavelength region component in visible light deteriorates, and when the film thickness is formed in the vicinity of 200 nm, the low wavelength region component in visible light Reflectivity deteriorates. For this reason, the dielectric film 551 is preferably formed to have a film thickness near the center wavelength in the visible light region as described above.

  Further, as shown in FIG. 4, a plurality of holes 554 are formed in the dielectric film 551, and the air layer 553 communicates with the holes 554. The diameter of the hole 554 is 0.3 μm to 100 μm, and the area occupied by the hole 554 is sufficiently smaller than the area of the entire mirror surface formed in a circular shape with a diameter of 3 mm. The mirror reflection characteristics and transmission characteristics due to the formation of 554 are not affected.

The post member 552 is a columnar member formed between a plurality of dielectric films 551 facing each other. The post member 552 holds the dielectric films 551 in parallel, and forms an air layer 553 that is a low refractive space between the dielectric films 551. As a material for forming the post member 552, for example, a material that can be shaped by etching, such as a resist formed of SiO ₂ , Ge, or an organic resin, can be used. In the present embodiment, an example in which the post member 552 is formed of translucent SiO ₂ is shown, and an example in which the post member 552 is opaque will be described in a second embodiment to be described later.

When the post member 552 is formed of a transparent material such as SiO _2, a portion for holding the dielectric film 551 by the post member 552 is compared with the entire area (mirror area) of the mirrors 56 and 57 in plan view. The area occupied is preferably 2% to 20%, for example. When the post member 552 has translucency, a mirror configuration (low reflection structure portion) in which the dielectric film 551 and the post member 552 are stacked is provided at the position where the post member 552 is provided. On the other hand, at a position where the post member 552 is not provided, a mirror configuration (high reflection structure portion) in which the dielectric film 551 and the air layer 553 are stacked is provided, and the mirror characteristics differ from the mirror characteristics at the position where the post member 552 is provided. It becomes a characteristic.
In general, in a dielectric multilayer film, mirror characteristics are determined by the difference in refractive index of each layer. The greater the difference in refractive index, the higher the reflectance and the wider the wavelength range that can be reflected. Therefore, as described above, when the post member 552 has translucency, there is a difference in mirror characteristics between the low reflection structure portion where the post member 552 is provided and the high reflection structure portion where the air layer 553 is provided, At the position where the post member 552 is provided, the reflectance is lowered, and the wavelength range where reflection is possible is also lowered.
In the etalon 5, when the inter-mirror gap G is set to a predetermined value, when the mirror characteristics are different as described above, the transmitted light has different wavelengths. That is, the wavelength of the light split by the low reflection structure portion where the post member 552 is provided and the wavelength of the light split by the high reflection structure portion where the air layer 553 is formed are different from each other. The two wavelengths of light are split and transmitted.
Therefore, as the area occupied by the post member 552 with respect to the mirror area increases, the light that passes through the low reflection structure at the position where the post member 552 is provided increases, and the light that passes through the high reflection structure portion that is originally desired to be dispersed by the etalon 5 is increased. descend. For this reason, the resolution of the light transmitted through the etalon 5 is lowered. If the area occupied by the post member 552 with respect to the mirror area is larger than 20%, it is difficult for the colorimetric sensor 3 to accurately detect the light amount of light having a desired wavelength, and the colorimetric processing accuracy of the inspection target light is increased. It will decline.

  On the other hand, when the area occupied by the post member 552 with respect to the mirror area is smaller than 2%, it is difficult to support the dielectric film 551 by the post member 552, and the dielectric film 551 may bend. That is, the plurality of dielectric films 551 need to be maintained in a parallel state by the post member 552, and when the dielectric film 551 bends, the wavelength range in which the reflectance can be reflected changes. Further, since the pair of mirrors 56 and 57 are not parallel due to the bending of the dielectric film 551, a difference in the gap G between the mirrors is generated depending on the mirror position, and the transmittance and resolution of the light transmitted through the etalon 5 are also reduced. . Therefore, the post member 552 needs to have an area for holding the dielectric film 551 in parallel, and the area occupied by the post member 552 with respect to the mirror area is preferably at least 2% or more.

Here, the condition for maintaining the dielectric film 551 in parallel is not determined only by the area occupied by the post member 552 with respect to the mirror area, but also the cross-sectional dimensions of the post member 552 and the film thickness of the dielectric film 551. The arrangement position of the post member 552 set based on this is also an important parameter. Therefore, as described above, the ratio of the post member 552 to the mirror area is set to 2%. However, depending on these parameters, for example, the area occupied by the post member 552 may be set to be larger.
Moreover, in the mirrors 56 and 57 of this embodiment, as shown in FIG. 5, each post member 552 has a predetermined first direction (vertical direction in the drawing of FIG. 5) and a second direction orthogonal to the first direction. (The horizontal direction on the paper surface of FIG. 5) and are arranged at equal intervals. Here, the interval between the post members 552 is appropriately set according to the film thickness of the dielectric film 551 and the cross-sectional area of the post member 552. For example, in this embodiment, the film thickness of the dielectric film 551 is 125 μm. The cross-sectional area of the post member 552 is set to 20 μm ^{2. In} this case, the other post member 552 is disposed within at least 500 μm ² of one post member 552 as the arrangement interval of the post members 552. It is preferable.

Focusing on one post member 552, when the post member 552 is sectioned along a plane parallel to the mirror surface, it is preferable that the minimum value of the cross-sectional dimension is 100 μm or less. Here, the minimum value of the cross-sectional dimension described in the present invention refers to the portion where the distance is the shortest in the cross-sectional shape of the post member 552 as described above. For example, the cross-section as shown in FIG. In the case of the post member 552, the dimension between the recesses B-C of the cross-sectional shape becomes the minimum value of the cross-sectional dimension. Further, when the cross-sectional shape of the post member 552 is circular, the diameter dimension, and when the cross-sectional shape is elliptical, it indicates the short axis dimension.
When the minimum value of the cross-sectional dimension is larger than 100 μm, even if the ratio of the post member 552 to the mirror area is 20% or less, the etalon is affected by the mirror characteristics of the portion where the post member 552 is provided. The transmittance of light passing through 5 and the resolution are reduced. On the other hand, when the cross-sectional dimension of the post member 552 is 100 μm or less, the influence of the change in the mirror characteristics due to the post member 552 can be sufficiently reduced, and the decrease in light transmittance and resolution can be ignored. Is possible.
Further, when the minimum value of the cross-sectional dimension is smaller than 1 μm, it is difficult to form the post member 552.
In this case, the cross-sectional dimensions of the post members are insufficient in strength, and it may be possible to maintain the dielectric films 551 facing each other in parallel. It is.

In general, in a dielectric multilayer mirror in which a high refractive index layer and a low refractive index layer are laminated, the reflection depends on the refractive index difference between the high refractive index layer and the low refractive index layer, the number of laminated layers, and the optical thickness of each layer. It is known that the wavelength range that can be reflected and reflected is determined.
That is, by setting the optical thickness of each layer to ¼ of the wavelength of light to be reflected, a high reflectance can be obtained in the vicinity of the wavelength. Further, as the difference in refractive index between the high refractive index layer and the low refractive index layer increases, the reflectance can be increased and the wavelength band that can be reflected can be increased. Furthermore, it is possible to improve the reflectivity by increasing the number of laminated dielectric films, but in this case, the reflective wavelength range is narrowed.
As described above, in order to set the wavelength band that can be dispersed by the etalon 5 to the entire visible light range (for example, 360 to 800 nm) and to improve the transmittance and resolution of the dispersed light, each of the mirrors 56 and 57 can be reflected. It is necessary to set the wavelength range to the visible light range, and in order to widen the reflective wavelength range without reducing the reflectivity, without reducing the number of layers, the high refractive index layer and the low refractive index layer It is necessary to increase the difference in refractive index.
In the mirrors 56 and 57 of this embodiment, as described above, the optical thickness of the dielectric film 551 and the thickness dimension of the air layer 553 (the height dimension of the post member 552) are formed to be 125 nm. Thus, it becomes possible to reflect light having a center wavelength of 600 nm, which is the center wavelength in the visible light region (for example, 360 nm to 800 nm) with high reflectance. The dielectric film 551 of TiO ₂ layer (refractive index≈2.5) becomes a high refractive index layer, and the air layer 553 (refractive index≈1.0) in a low refractive space becomes a low refractive index layer. The refractive index difference is 1.5, for example, compared to a TiO ₂ —SiO ₂ dielectric multilayer mirror (refractive index difference is 1.0), the refractive index difference is large, and the reflectance can be increased. In addition, the wavelength band that can be reflected can be widened.

(3-2. Configuration of voltage control means)
The voltage control means 6 constitutes the variable wavelength interference filter of the present invention together with the etalon 5. The voltage control means 6 controls the voltage applied to the first displacement electrode 541 and the second displacement electrode 542 of the electrostatic actuator 54 based on the control signal input from the control device 4.

[4. Configuration of control device]
The control device 4 controls the overall operation of the color measurement module 1.
As the control device 4, for example, a general-purpose personal computer, a portable information terminal, other color measurement dedicated computer, or the like can be used.
As shown in FIG. 1, the control device 4 includes a light source control unit 41, a colorimetric sensor control unit 42, a colorimetric processing unit 43, and the like.
The light source control unit 41 is connected to the light source device 2. Then, the light source control unit 41 outputs a predetermined control signal to the light source device 2 based on, for example, a user setting input, and causes the light source device 2 to emit white light with a predetermined brightness.
The colorimetric sensor control unit 42 is connected to the colorimetric sensor 3. The colorimetric sensor control unit 42 sets a wavelength of light received by the colorimetric sensor 3 based on, for example, a user's setting input, and outputs a control signal for detecting the amount of light received at this wavelength. Output to the colorimetric sensor 3. Thereby, the voltage control means 6 of the colorimetric sensor 3 sets the voltage applied to the electrostatic actuator 54 so as to transmit only the wavelength of light desired by the user based on the control signal.

[5. Etalon Manufacturing Method)
Next, a method for manufacturing the etalon 5 will be described with reference to the drawings.
6A and 6B are diagrams illustrating a manufacturing process of the etalon 5, in which FIG. 6A is a schematic diagram of the first substrate 51 and the second substrate 52 in the substrate forming process, and FIG. 6B is a first substrate 51 in the mirror forming process. And (C) is a schematic view of the first substrate 51 and the second substrate 52 in the electrode forming step, and (D) is an etalon 5 formed after the joining step and the diaphragm forming step. FIG.

  As shown in FIG. 6, in order to manufacture the etalon 5, first, as shown in FIG. 6A, a glass substrate which is a manufacturing material of the first substrate 51 is processed to form each groove ( Substrate forming step). Specifically, for the first substrate 51, a resist is formed on the bonding surface 513, and portions other than the bonding surface 513 are etched to form the electrode formation groove 511. Thereafter, a resist is further formed on the electrode fixing surface 511A of the electrode forming groove 511 to form the mirror fixing groove 512.

Thereafter, as shown in FIG. 6B, a mirror forming step is formed. For this purpose, a resist is formed on the first substrate 51 and the second substrate 52 other than the portions where the mirrors 56 and 57 are formed, and the mirrors 56 and 57 are formed.
In this mirror forming step, mirrors 56 and 57 are formed by each step as shown in FIGS. FIG. 7 is a diagram illustrating a stacking process in the mirror forming process. 8A and 8B are diagrams showing a hole forming process in the mirror forming process, where FIG. 8A is a cross-sectional view schematically showing the mirrors 56 and 57 after the hole forming process, and FIG. 8B is formed by the hole forming process. It is a figure showing an example of a position of hole 554. 7 and 8, the diameter dimension of the hole 554 is shown large for the sake of explanation, but it is actually formed to be sufficiently small with respect to the mirror area. A 16-layer structure (8 dielectric films 551 and 8 sacrificial layers 555) is formed.

In the mirror forming step, first, as shown in FIG. 7, a sacrificial layer 555 made of a material for forming the post member 552 (in this embodiment, SiO ₂ ) on the first substrate 51 and the second substrate 52, and a dielectric A laminated body 55 is formed by alternately laminating body films 551 (TiO ₂ ) (lamination process). Each of these layers is formed by sputtering so that the film thickness becomes 125 nm.

Thereafter, as shown in FIG. 8, holes 554 are formed in the stacked body 55 formed by the stacking process (hole forming process). In this hole forming step, a hole 554 that penetrates from the upper surface of the stacked body 55 to the substrate surface of the first substrate 51 (second substrate 52) is formed along the mirror thickness direction. In the present embodiment, a circular hole 554 is formed in a plan view of the mirror shown in FIG. As described above, the diameter of the hole 554 is 0.3 μm to 100 μm, and is formed to a size that does not affect the mirror characteristics. In addition, as a method for forming the hole 554, a resist is formed on the surface of the stacked body 55 other than the position where the hole 554 is formed. For example, a CF-based gas such as CF ₄ or CHF ₃ or xenon fluoride is used as an etching gas. A hole 554 is formed by dry etching.

Next, the post formation step of forming the post member 552 and the air layer 553 is performed by etching the sacrificial layer 555 around the hole 554 formed in the hole formation step.
In this post formation step, a xenon fluoride etching gas is flowed into the hole 554 and isotropic dry etching is performed for a predetermined time to remove a part of the sacrificial layer 555. The time for performing dry etching is appropriately set according to the cross-sectional dimensions of the post member 552 to be formed and the flow rate of the etching gas. As a result, the sacrificial layer 555 within the range of the predetermined diameter from the center of the hole 554 is removed, and the sacrificial layer 555 outside this range remains, so that the post member 552 as shown in FIGS. Is formed.
In this embodiment, since the sacrificial layer 555 is formed of SiO ₂ , the above-described xenon fluoride dry etching is performed. However, when the sacrificial layer 555 is formed of Ge, the sacrificial layer 555 is similarly fluorinated. The post member 552 can be formed by xenon-based dry etching. In the case where the sacrificial layer 555 is formed of an organic resin resist, the resist within a predetermined range is removed from the hole 554 by O ₂ ashing to form the post member 552. In this embodiment, an example in which the sacrificial layer 555 is removed by dry etching has been described. However, for example, a manufacturing method in which the post member 552 is formed by performing wet etching with hydrogen peroxide water may be used.

Thereafter, as shown in FIG. 6C, a resist is formed on the first substrate 51 other than the electrode formation portion and the second substrate 52 other than the electrode formation portion, and the first displacement is applied to the first substrate 51 by sputtering. The electrode 541 is formed, and the second displacement electrode 542 is formed on the second substrate 52 (electrode formation step). At this time, the surface of the first substrate 51 that does not face the second substrate 52, the position that overlaps the fixed mirror 56 in the mirror plan view, and the surface that does not face the first substrate 51 of the second substrate 52 in the mirror plan view. Antireflection films are respectively formed at positions overlapping the movable mirror 57.
And the 1st board | substrate 51 and the 2nd board | substrate 52 which were formed as mentioned above are piled up, and the joint surfaces 513 and 524 are joined (joining process). Thereafter, as shown in FIG. 6D, a groove for forming the connection holding portion 522 is formed in the second substrate 52 by etching (diaphragm formation step). Thus, the etalon 5 is manufactured.
In addition, although the manufacturing method which implements a diaphragm formation process after a joining process was illustrated, it is not limited to this, For example, you may implement a diaphragm formation process with respect to the 2nd board | substrate 52 in a substrate formation process.

[6. Effect of First Embodiment)
As described above, in the etalon 5 of the above embodiment, the mirrors 56 and 57 formed on the first substrate 51 and the second substrate 52 are formed by the plurality of dielectric films 551, and between these dielectric films 551. By providing the post member 552, an air layer 553 that is a low refractive space is provided between the dielectric films 551.
Thus, the mirrors 56 and 57 are formed by the dielectric film 551 having a high refractive index and the air layer 553 having a low refractive index, so that the dielectric film 551 and a solid low refractive index such as a SiO ₂ layer are formed. Compared with the dielectric multilayer mirror formed by the index layer, the difference in the refractive index between the respective layers becomes larger, and the wavelength range that can be reflected by the mirrors 56 and 57 can be expanded. In the etalon 5, the wavelength of transmitted light can be varied by controlling the electrostatic actuator 54 and adjusting the inter-mirror gap G between the pair of mirrors 56 and 57, but as described above. When the wavelength range that can be reflected by each of the mirrors 56 and 57 becomes wider, light in a wider wavelength range can be reflected between the pair of mirrors 56 and 57 of the etalon 5, and by adjusting the gap G between the mirrors, It is possible to split and transmit only light having a desired wavelength from light in these wide wavelength ranges. That is, the wavelength range of light that can be dispersed by the etalon 5 can be expanded. As described above, by setting the number of stacked dielectric films 551 and air layers 553 to a 16-layer structure, light with a wavelength in the entire visible light range can be selectively transmitted.
Further, by using the mirrors 56 and 57 in which a plurality of dielectric films 551 and air layers 553 are stacked, the reflectance is higher than that in the case of using, for example, a single AgC layer mirror, and the spectrum is split by the etalon 5. The transmittance and resolution of light can be increased.
Further, by holding the dielectric film 551 by the post member 552, the dielectric film 551 can be maintained in parallel, and the pair of mirrors 56 and 57 can also be maintained in parallel. Therefore, the reflectance of the mirrors 56 and 57 is not reduced due to the deflection of the dielectric film 551, and the transmittance and resolution of the light split by the etalon 5 due to the deflection of the mirrors 56 and 57 can be prevented.
As described above, in the etalon 5 of the present embodiment, it is possible to widen the spectral wavelength range to the entire visible light range without reducing the transmittance and resolution of the transmitted light.

Further, the post member 552 is formed of SiO ₂ which is a transparent material, and the total area occupied by the post member 552 in a plan view of the mirrors 56 and 57 is 20% or less with respect to the total area of the mirror. Has been.
For this reason, the amount of light transmitted through the low reflection structure portion, which is a laminated portion of the translucent post member 552 and the dielectric film 551, is reduced, and the high reflection portion, which is a laminated portion of the air layer 553 and the dielectric film 551. The amount of light transmitted through the structure portion can be increased.
Here, as described above, when the area occupied by the post member 552 with respect to the mirror area is larger than 20%, the amount of light that is split and transmitted by the laminated portion of the post member 552 and the dielectric film 551 increases. , The full width at half maximum of the transmittance of the light split by the etalon 5 is widened. That is, there is a problem that the resolution is lowered. On the other hand, by setting the ratio of the post member 552 to 20% or less with respect to the mirror area, the influence on the laminated portion of the post member 552 and the dielectric film 551 can be sufficiently reduced. The half width of the rate is narrowed, and the resolution can be increased as described above.

  Further, when the minimum value of the cross-sectional dimension of one post member 552 is larger than 100 μm, as described above, even when the ratio of the post member 552 to the mirror area is 20% or less, the post member 552 and the dielectric In some cases, the resolution is deteriorated due to the influence of the mirror characteristics of the layered portion with the body film 551. On the other hand, in this embodiment, since the cross-sectional dimension of the post member 552 is formed to be 100 μm or less, the influence of the mirror characteristics of the laminated portion of the post member 552 and the dielectric film 551 can be sufficiently reduced, and the etalon The decrease in resolution of 5 can be suppressed.

  The post members 552 are arranged at equal intervals along the vertical and horizontal directions in the plan view of the mirrors 56 and 57. For this reason, since the dielectric film 551 is uniformly held by these post members 552, for example, it is possible to prevent inconveniences such as a part of the film from being bent, and to prevent a decrease in the transmittance of the etalon 5 and a decrease in the resolution. be able to.

The mirrors 56 and 57 in the etalon 5 are formed by a laminating process, a hole forming process, and a post forming process.
In such a manufacturing method, the mirrors 56 and 57 each holding the dielectric film 551 by the post member 552 can be easily manufactured.
That is, in manufacturing the mirrors 56 and 57, for example, after each dielectric film 551 is formed, a plurality of post members 552 are arranged on the dielectric film 551, and the dielectric film 551 is formed again from above. Thus, it is also possible to form the mirrors 56 and 57 in which the dielectric film 551 and the air layer 553 are stacked. However, in this manufacturing method, in order to form the post member 552, a resist having a hole corresponding to the arrangement position of the post member 552 is formed on the dielectric film 551, and the post member 552 is formed in the hole of the resist. In addition, it is necessary to form a dielectric film 551 on these resist and post member 552, and finally it is necessary to peel only the resist. That is, a resist formation process and a resist removal process are separately required, and the manufacturing process increases. On the other hand, in the formation of the mirrors 56 and 57 in the present embodiment, a plurality of air layers 553 and post members 552 are manufactured at a time only by flowing an etching gas into the holes 554 formed in the stacked body 55. be able to. In addition, since it is not necessary to separately form a resist or remove these resists for manufacturing the post member 552, the number of manufacturing steps is reduced. As described above, by providing the mirrors 56 and 57 by the manufacturing method as described above, the manufacturing efficiency of the mirrors 56 and 57 can be improved, and as a result, the manufacturing efficiency of the etalon 5 can also be improved.

[Second Embodiment]
Next, the color measurement module according to the second embodiment of the present invention will be described with reference to the drawings.
FIG. 9 is a cross-sectional view showing a schematic configuration of the mirrors 56 and 57 of the second embodiment.
In the following description of the embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  In the color measurement module 1 of the first embodiment, the pair of mirrors 56 and 57 constituting a part of the etalon 5 are interposed between the plurality of dielectric films 551 with the post member 552 formed of a transparent material. An air layer 553 was formed. On the other hand, in the etalon 5 of the second embodiment, the mirrors 56 and 57 are provided with a post member 552A formed of an opaque material between the plurality of dielectric films 551, and these opaque post members 552A. Thus, the dielectric film 551 is held.

  Specifically, as shown in FIG. 9, in the mirrors 56 and 57, holes 554 are formed in the dielectric films 551, and opaque post members 552 </ b> A are passed through the holes 554, so that the dielectric films 551 are formed. Is fixed. As in the first embodiment, the hole 554 is formed with a diameter of 0.3 μm to 100 μm, and the hole 554 occupies the area of the entire mirror surface formed in a circular shape with a diameter of 3 mm. The area is formed sufficiently small.

In the mirrors 56 and 57, it is preferable that the total area occupied by the portion holding the dielectric film 551 by the post member 552 is 2% to 50% with respect to the total area of the mirror.
In the etalon 5 as in the first embodiment, since the post member 552 has translucency, a dielectric multilayer film mirror in which the post member 552 and the dielectric film 551 are laminated at the position where the post member 552 is provided. The mirror characteristics are different from those of the laminated portion of the air layer 553 and the dielectric film 551. Therefore, the position where the post member 552 is provided contributes to a reduction in the resolution of the transmitted light of the etalon 5, and it is necessary to limit the proportion of the post member 552 to 20% or less of the mirror area.
On the other hand, in the mirrors 56 and 57 of the second embodiment, the post member 552A is an opaque member, and no light is reflected or transmitted at the position where the post member 552A is provided. Therefore, the post member 552A does not widen the half width of the transmittance of the light transmitted through the etalon 5, and the resolution is not lowered.
On the other hand, since the opaque post member 552A does not transmit light, the larger the area of the post member 552A with respect to the mirror area, the more light is absorbed by the post member 552A. Therefore, the amount of light transmitted through the etalon 5 decreases. When the area occupied by the post member 552A with respect to the mirror area becomes larger than 50%, the light transmitted through the etalon 5 decreases, and it becomes difficult for the colorimetric sensor 3 to accurately detect the light amount of the desired wavelength. The accuracy of the colorimetric processing of the inspection target light is reduced. On the other hand, by setting the area occupied by the post member 552A to the mirror area to be 50% or less, it is possible to obtain a sufficient amount of light for performing highly accurate color measurement processing.

  Further, other formation conditions of the post member 552A are the same as those of the post member 552 of the first embodiment, and each post member 552A has a cross-sectional dimension of 100 μm or less. Further, the post members 552A are evenly arranged along the vertical direction and the horizontal direction, and the interval between the post members 552A is equal to or less than a predetermined interval threshold necessary for preventing the dielectric film 551 from being bent. It is arranged to become. The arrangement interval of the post members 552A is determined by the thickness dimensions of the dielectric films 551 and the cross-sectional dimensions of the post members 552A, as in the first embodiment.

(Mirror manufacturing method)
Next, the manufacturing method of the etalon 5 of the second embodiment will be described based on the drawings.
The production of the etalon 5 of the second embodiment is formed by a substrate formation process, a mirror formation process, an electrode formation process, a bonding process, and a diaphragm formation process in substantially the same manner as the production method of the first embodiment. Among these, the contents of the mirror forming step are different from those of the first embodiment.

10A and 10B are diagrams showing a mirror formation configuration of the second embodiment, in which FIG. 10A shows a stacking process, FIG. 10B shows a hole forming process, and FIG. 10C shows a post-embedding process.
In the mirror forming step of the second embodiment, first, as shown in FIG. 10A, dielectric films 551 (for example, TiO ₂ layers) and sacrificial layers 555 (for example, SiO ₂ layers) are alternately stacked, The laminated body 55 is comprised. This is the same as the laminating step of the mirror forming step in the first embodiment, and is formed by sputtering so that the thickness dimension of each layer is 125 nm.

Next, as shown in FIG. 10B, a hole forming step for forming a hole 554 penetrating from the upper surface of the stacked body 55 to the substrate surface is performed. Here, the hole 554 formed in the second embodiment is a position where the post member 552A is formed, and the hole 554 corresponding to the diameter of the post member 552A is formed.
Specifically, in the hole forming step, each hole 554 is formed such that the area occupied by the hole 554 is 50% or less with respect to the total area of the mirror, and the sectional dimension of one hole 554 is 100 μm or less. In the second embodiment, as in the first embodiment, the post members 552A are arranged at equal intervals in the predetermined vertical direction on the mirror surface and in the horizontal direction perpendicular to the vertical direction. In this case, in the hole forming step, the holes 554 are formed at equal intervals in the vertical direction and the horizontal direction. At this time, as described above, each hole 554 is formed at an interval equal to or less than a predetermined interval threshold value determined by the thickness dimension of the dielectric film 551 and the diameter dimension of the hole 554.

Thereafter, a post member embedding step for embedding the post member 552A in each hole 554 is performed. Since the post member 552A does not need to be formed by etching as in the first embodiment, the material selection range is widened. For example, in this embodiment, a metal such as W, Au, or Cr is used. A material can be used as the post member 552A.
Here, in this post embedding process, for example, the post member 552A is embedded in the hole 554 by press-fitting the rod-shaped post member 552A into the hole 554.

Then, after this post member embedding step, a sacrificial layer removing step for removing the sacrificial layer 555 is performed, whereby the mirrors 56 and 57 are formed.
Specifically, in this sacrificial layer removal step, the sacrificial layer 555 (SiO ₂ layer) is removed by dry etching the sacrificial layer 555 from the side surface portion of the stack by flowing a xenon fluoride etching gas. .
If the sacrificial layer 555 is a SiO ₂ layer or a Ge layer as in the present embodiment, a sacrificial layer removing step by dry etching is performed. For example, an organic resin is used as the sacrificial layer 555. In the case where the resist is formed, etching can be performed by O ₂ ashing or the like. Further, the sacrificial layer 555 may be removed by performing wet etching using hydrogen peroxide or the like without being limited to dry etching.

[Effects of Second Embodiment]
In the etalon 5 of the second embodiment, the post member 552A is formed of an opaque material, and the ratio of the post member 552A to the total mirror area is 50% or less.
Since the post member 552A is opaque, the laminated portion of the post member 552A and the dielectric film 551 does not transmit light and does not affect the mirror characteristics of the mirrors 56 and 57. Therefore, even when the area occupied by the laminated portion of the post member 552A and the dielectric film 551 increases, the resolution of the etalon 5 as in the first embodiment is not reduced.
On the other hand, if the area occupied by the laminated portion of the post member 552A and the dielectric film 551 is larger than 50% with respect to the mirror area, this portion does not transmit light, so the amount of light transmitted through the etalon 5 also decreases. End up. On the other hand, in the present embodiment, the ratio of the portion occupied by the post member 552A to the total area of the mirror in a plan view of the mirror is 50% or less, and the color reduction of the etalon 5 is measured. It can be maintained to the extent possible.

Further, in the manufacture of the etalon 5, in the mirror forming process, after forming the hole 554 in the hole forming process in the stacked body 55 formed in the stacking process, the post member 552A is provided with the post member 552A in the post member embedding process. The post member 552A is formed by embedding. Then, the air layer 553 is formed by removing the sacrificial layer 555 in the sacrificial layer removing step.
In the embedding of the post member 552A as described above, each post member 552A needs to be embedded in each hole 554, so the operation in this post member embedding process becomes complicated, but after embedding the post member 552A, In the sacrificial layer removal step, all the sacrificial layers 555 in the stacked body 55 may be removed. Therefore, unlike the first embodiment, there is no need to form the post member 552 when removing the sacrificial layer 555, and no precise operation is required to remove the sacrificial layer 555. Further, in the first embodiment, the material of the post member 552 is limited to a material whose shape can be formed by etching. However, in the second embodiment, the post member 552A is formed by embedding, and thus various materials are used. The post member 552A can be selected. Therefore, it is possible to select a metallic post member 552A having a strength necessary for holding the dielectric films 551 in parallel. In this case, the dielectric film 551 can be more reliably prevented from being bent, It is possible to suppress a decrease in the transmittance and resolution of light split by the etalon 5.

[Third embodiment]
Next, an etalon of the color measurement module according to the third embodiment of the present invention will be described with reference to the drawings.
The third embodiment is different in the configuration of the mirrors 56 and 57 of the etalon 5 in the color measurement module 1 of the first embodiment. FIG. 11 is a diagram showing a schematic configuration of the mirrors 56 and 57 in the etalon 5 of the third embodiment.

In the first embodiment, the post member 552 is formed of SiO _2. However, the post member 552B of the third embodiment is formed of TiO ₂ which is the same material as the dielectric film 551. In the first embodiment, the hole 554 for forming the air layer 553 is not formed.
Here, the area where the post member 552B is formed is the same as in the first embodiment, and the ratio of the post member 552B to the mirror 56, 57 in a plan view is 20% or less with respect to the total area of the mirror. The post member 552B has a cross-sectional dimension of 100 μm or less.

[Mirror manufacturing method]
Next, the mirror formation process in manufacture of the etalon 5 of 3rd embodiment is demonstrated based on drawing.
The etalon 5 of the third embodiment is formed by a substrate forming process, a mirror forming process, an electrode forming process, a bonding process, and a diaphragm forming process, as in the manufacturing method of the first embodiment. Among these, the contents of the mirror forming step are different from those of the first embodiment.

  12A and 12B are diagrams illustrating a stacking process in the mirror forming process of the third embodiment, in which FIG. 12A is a first sacrificial layer forming process for forming the lowermost sacrificial layer 555, and FIG. A first dielectric layer forming step of forming the dielectric film 551 and the post member 552B, (C) is a second sacrificial layer forming step of forming the sacrificial layer 555 on the dielectric film 551, and (D) is a dielectric. FIG. 10 is a diagram showing a second dielectric layer forming step of forming a dielectric film 551 on a film 551 and a sacrificial layer 555.

As shown in FIG. 12, in the mirror forming step of the third embodiment, first, in the stacking step, a stacked body 55A in which a sacrificial layer 555 and a dielectric layer 556 are stacked is formed.
Here, in this stacking step, as shown in FIG. 12A, first, a sacrificial layer 555 is formed on the first substrate 51 and the second substrate 52 (first sacrificial layer forming step). The sacrificial layer 555 is formed in, for example, a net shape or a rod shape in a mirror plan view, and is formed so that an end portion thereof is exposed on the side surface of the stacked body 55A. Here, FIG. 13 shows an example of a plan view of the sacrificial layer 555 when the sacrificial layer 555 is formed in a net shape. As shown in FIG. 13, the space surrounded by the net-like sacrificial layer 555 is the position where the post member 552B is formed.
As a specific method for forming the sacrificial layer 555, a resist is formed on the first substrate 51 and the second substrate 52 corresponding to the position of the post member 552B, and the sacrificial layer 555 is formed by sputtering. Thereafter, by removing the resist, a sacrificial layer 555 provided with a hole 555A for forming the post member 552B is formed.
Note that the shape of the sacrificial layer 555 is not limited to the net shape as described above, and a plurality of rod-shaped sacrificial layers 555 may be formed. In this case, the space between the rod-like sacrificial layers 555 is the position where the post member 552B is formed.

Next, a first dielectric layer forming step for forming a dielectric layer 556 on the sacrificial layer 555 is performed. In the first dielectric layer forming step, a dielectric layer 556 is formed so as to cover the sacrificial layer 555 as shown in FIG. For this purpose, a new resist is formed on the first substrate 51 and the second substrate 52, and only the positions where the mirrors 56 and 57 are formed are opened. Then, a dielectric layer 556 (TiO ₂ layer) is laminated and formed on the hole 555A and the surface of the sacrificial layer 555 at the mirror forming portions of the first substrate 51 and the second substrate 52 by sputtering or the like.
Here, the dielectric layer 556 is formed so that the surface thereof is parallel to the substrate surface of the first substrate 51 or the second substrate 52.

Thereafter, as shown in FIG. 12C, a second sacrificial layer forming step for forming a sacrificial layer 555 on the surface of the dielectric layer 556 is performed.
In this second sacrificial layer forming step, a sacrificial layer 555 having a hole 555A is formed on the surface of the dielectric layer 556 by the same formation method as the sacrificial layer 555 formed in the first sacrificial layer forming step.
After that, as shown in FIG. 12D, a second dielectric layer forming step for forming the dielectric layer 556 is performed so as to cover the sacrificial layer 555 formed on the surface of the dielectric layer 556.
In the second dielectric layer forming step, the dielectric layer 556 is covered with the sacrificial layer 555 on the surface of the dielectric layer 556 by the same formation method as the dielectric layer 556 formed in the first dielectric layer forming step. Form.
Then, by repeatedly performing the second sacrificial layer forming step and the second dielectric layer forming step, a stacked body 55A in which a predetermined number of dielectric layers are stacked is formed.

  Thereafter, only the sacrificial layer 555 is removed by dry etching, for example, by flowing a xenon fluoride etching gas from the side surface of the stacked body 55A formed in the above-described stacking process (sacrificial layer removing process). Thus, the dielectric film 551 is held by the post member 552B formed in the space formed between the sacrificial layers 555, and the mirrors 56 and 57 in which the air layer 553 is formed between the dielectric films 551 are manufactured. .

[Operational effects of the third embodiment]
In the etalon 5 of the third embodiment, when the mirrors 56 and 57 are formed, after the sacrificial layer 555 and the dielectric layer 556 are stacked in the stacking process, the sacrificial layer 555 is simply removed in the sacrificial layer removing process. 552B is formed. Therefore, the hole forming process for forming the hole 554, which is essential in the mirror forming process of the first embodiment or the second embodiment, is not necessary, and the mirrors 56 and 57 can be manufactured in a shorter process.

[Fourth embodiment]
Next, the etalon 5 of the color measurement module according to the fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 14 is a diagram showing a configuration of the etalon 5 of the fourth embodiment.
In the etalon 5 of the first to third embodiments described above, the mirrors 56 and 57 in which the air layer 553 is formed between the dielectric films 551 by the post members 552, 552A, and 552B are provided, but in the fourth embodiment, A vacuum layer 557 is formed between the dielectric films 551.

Specifically, the etalon 5 is housed in a sealed package 58 as shown in FIG. For example, the surface of the package 58 facing the first substrate 51 and the second substrate 52 of the etalon 5 is formed of a translucent substrate. Further, the package 58 holds the etalon 5 at a predetermined position inside the package 58 by holding the outer peripheral portion of the etalon 5 on the inner peripheral side surface, for example. In this package 58, the sealed internal space is kept in a vacuum state.
Such an etalon 5 forms the vacuum layer 557 between the dielectric films 551 by forming the etalon 5 in the same manufacturing process as in the first embodiment in a vacuum atmosphere. In this vacuum atmosphere, the formed etalon 5 is fixed at a predetermined position in the sealed package 58, and the lid of the package 58 is closed and sealed. Thereby, the inside of the sealed package 58 is maintained in a vacuum state, and the vacuum layer 557 between the dielectric films 551 in the mirrors 56 and 57 is also maintained in a vacuum state.

  In the etalon 5 of the fourth embodiment as described above, the vacuum layer 557 is formed between the dielectric films 551 of the mirrors 56 and 57. Since the refractive index of vacuum is smaller than the refractive index of air, the difference in refractive index between the high refractive index layer (dielectric film 551) constituting the mirrors 56 and 57 and the low refractive index layer (vacuum layer 557) is Compared with the case where the air layer 553 is used as the low refractive index layer, it can be made larger. Therefore, the reflectance in the mirrors 56 and 57 can be increased, and the wavelength range where reflection is possible can be further expanded. That is, the wavelength band that can be dispersed by the etalon 5 can be further expanded, and the visible light region can be covered as the spectrally dispersible wavelength region.

  Further, when the etalon 5 separates light of a predetermined wavelength, a voltage is applied to the electrostatic actuator 54 according to the wavelength of light to be dispersed, and the movable portion 521 is moved to change the inter-mirror gap G. Let Here, when the low refractive space between the dielectric films 551 is the air layer 553, air resistance is applied to each dielectric film 551 of the movable mirror 57. Therefore, if the moving speed of the movable portion 521 is high, the dielectric film 551. May be bent due to air resistance, and it is necessary to slow down the movement of the movable portion 521. On the other hand, in this embodiment, since the vacuum layer 557 is formed between the dielectric films 551, no resistance is applied to the dielectric film 551 due to the movement of the movable portion 521. Therefore, even when the fluctuation speed of the movable portion 521 is increased, the dielectric film 551 is not bent and does not affect the transmission characteristics of the etalon 5.

  Further, since the etalon 5 is housed in a sealed package 58 in which the inside is maintained in a vacuum, there is no air resistance applied to the movable portion 521 and the connection holding portion 522, and the movement of the movable portion 521 can be made smoother. it can. Therefore, the moving speed of the movable portion 521 when a predetermined voltage is applied to the electrostatic actuator 54 can be made faster than, for example, when the etalon 5 is operated in the air.

[Other Embodiments]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the description of the first embodiment, an example in which the cross-shaped post member 552 is formed in the post member forming process by forming the circular holes 554 at regular intervals in the mirror plan view is shown. The shape of the post member 552 is not limited to this. For example, the shape of the post member 552 as shown in FIGS. 15 and 16 may be used. 15 and 16 are views showing other shapes of the post member 552 and the hole 554. FIG. In FIGS. 15 and 16, for the sake of explanation, the dimensions of the hole 554 and the post member 552 are shown large, but in reality, the transmission characteristics of the etalon 5 and the colorimetric processing are affected. It is formed small enough so that it does not exist.
Specifically, FIG. 15 shows the shape of the post member 552 when the arc-shaped groove-shaped hole 554 is formed. As shown in FIG. 15A, in the hole forming step, arc-shaped holes 554 are formed along a plurality of concentric circles with the center point of the mirrors 56 and 57 as the center. By forming the hole 554 having such a shape, a circular post member 552 as shown in FIG. 15B is formed. Even in this case, the sacrificial layer is dry-etched so that the width dimension of each post member 552 is 100 μm or less, so that deterioration of the transmittance due to the post member 552 can be suppressed. Further, even a post member having a closed space as shown in FIG. 15B has no problem in etalon characteristics, and may be a cylindrical post member or the like.
FIG. 16 shows an example in which a columnar post member 552 is formed. In this example, a cross-shaped hole 554 is formed, and the sacrificial layer is removed by etching processing around the hole 554, thereby forming a post member 552 having a circular cross section as shown in FIG. it can.
Also, the shape of the post member 552 is not particularly limited with respect to the second to fourth embodiments. For example, a configuration in which an annular post member is provided in a plan view as shown in FIG. And so on.

  Furthermore, in the said embodiment, although the post member 552 showed the example arrange | positioned by the post member 552 equal intervals with respect to the vertical direction and a horizontal direction, respectively, it is not restricted to this. For example, the post member 552 may be arranged along a plurality of virtual circles having different diameters that are concentric with respect to the center point of the mirrors 56 and 57. Even in this case, the diameter dimension of each virtual circle and the arrangement interval (arrangement angle interval) of the post members 552 on each virtual circle are appropriately determined by the thickness dimension of the dielectric film 551 and the cross-sectional dimension of each post member 552. When the dielectric film 551 is not bent and the post member 552 is a transparent member, the area occupied by all the post members 552 in the mirror plan view is 20% or less with respect to the total area of the mirror. When the post member 552 is an opaque member, the post member 552 may be arranged so that the area occupied by all the post members 552 is 50% or less with respect to the total area of the mirror.

In the first embodiment, the example in which the ratio of the post member 552 to the total area of the mirror is 20% or less in the mirror plan view is shown, but the present invention is not limited to this. For example, the post member 552 is formed of a material having a lower refractive index, such as the post member 552 made of MgF ₂ (refractive index = 1.37), so that the mirror characteristics in the low reflective structure portion can be improved. In this case, for example, even if the area occupied by the post member 552 with respect to the total area of the mirror is set to 20% or more, a decrease in resolution of the etalon 5 can be suppressed.
However, even in the case of the above configuration, since the resolution of the light split by the etalon 5 can be reduced compared to the above embodiment, the post member 552 is a transparent member as in the above embodiment. In this case, the ratio of the area occupied by the post member 552 to the mirror area is preferably set to 20% or less.

Further, in the second embodiment, the example in which the ratio of the post member 552 to the total area of the mirror is 20% or less in the mirror plan view is shown, but the present invention is not limited to this. For example, by using mirrors 56 and 57 having a larger area, the amount of light transmitted through the etalon 5 also increases. In this case, the area occupied by the post member 552 with respect to the total area of the mirror is set to 50% or more. In other words, it is possible to suppress a decrease in the amount of light transmitted by the etalon 5.
However, when the areas of the mirrors 56 and 57 are increased, there is a problem that it is difficult to maintain the parallel relationship between the pair of mirrors 56 and 57. Therefore, the dimensions of the mirrors 56 and 57 are set as in the above embodiment. It is preferable that the diameter of the post member 552 is set to 50% or less with respect to the total area of the mirror.

  Furthermore, although the post member 552 has been shown as an example in which the minimum value of the cross-sectional dimension is 100 μm or less, the post member 552 has a cross-sectional dimension of 100 μm or more depending on the material of the post member 552 and the mirror area as described above. It can also be set as the structure formed in this.

  In the fourth embodiment, the example in which the vacuum layer 557 is formed by fixing the etalon 5 in the package 58 whose inside is vacuum-sealed has been described, but the present invention is not limited to this. For example, a third substrate is bonded to the side surface opposite to the first substrate 51 of the second substrate 52 on which the movable portion 521 is formed, and the internal space between the first substrate 51 and the second substrate 52, the second substrate 52. Further, the vacuum layer 557 may be formed by making the internal space of the third substrate in a vacuum state. In this case, since the space between the second substrate 52 and the third substrate is evacuated, the movable portion 521 is sandwiched between the vacuum spaces, and the movable portion is not subjected to air resistance. Therefore, the movable portion 521 is moved by the electrostatic actuator. The displacement speed at the time of displacing can be improved.

  In the first, second, and third embodiments, the post member 552 forms an air layer 553 that is a low refractive space between the dielectric films 551, and this air layer forms the gas layer of the present invention. However, the gas layer is not limited to air. For example, the gas layer may be a gas having a low refractive index and a small wavelength absorbability within the visible light range. For example, the gas layer may be formed of helium gas.

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

  DESCRIPTION OF SYMBOLS 1 ... Color measuring module, 3 ... Color measuring sensor, 5 ... Etalon which is a wavelength variable interference filter, 31 ... Light receiving element which is light receiving means, 43 ... Color measuring processing part, 54 ... Electrostatic actuator which is variable means, 56 ... Fixed mirror, 57 ... movable mirror, 551 ... dielectric film, 552, 552A, 552B ... post member, 553 ... air layer as gas layer, 555 ... sacrificial layer, 555A ... hole, 556 ... dielectric layer, 557 ... Vacuum layer.

Claims (12)

A pair of mirrors facing each other;
Variable means for varying the interval between the mirrors,
The mirror includes a plurality of dielectric films, and a post member provided between the dielectric films to hold the dielectric films facing each other in parallel and to form a space between the dielectric films. A wavelength tunable interference filter comprising: The tunable interference filter according to claim 1,
The post member is a transparent member,
The ratio of the area occupied by the post member to the total area of the mirror in a plan view of the mirror is 20% or less. The tunable interference filter according to claim 1,
The post member is an opaque member;
The ratio of the area occupied by the post member to the total area of the mirror in a plan view of the mirror is 50% or less. In the wavelength variable interference filter according to any one of claims 1 to 3,
The wavelength variable interference filter, wherein the post member has a minimum cross-sectional dimension of 100 μm or less when the post member is sectioned along a plane parallel to the mirror surface. In the wavelength variable interference filter according to any one of claims 1 to 4,
The wavelength tunable interference filter, wherein the space is a vacuum layer. In the wavelength variable interference filter according to any one of claims 1 to 4,
The said space is a gas layer. The variable wavelength interference filter characterized by the above-mentioned. In the wavelength variable interference filter according to any one of claims 1 to 6,
The wavelength tunable interference filter, wherein the dielectric film of the mirror is formed of titanium oxide. The wavelength variable interference filter according to any one of claims 1 to 7,
A light receiving means for receiving light transmitted through the wavelength variable interference filter;
A colorimetric sensor comprising: A colorimetric sensor according to claim 8;
A colorimetric processing unit that performs colorimetric processing based on the light received by the light receiving means of the colorimetric sensor;
A color measurement module characterized by comprising: A method for manufacturing a wavelength tunable interference filter according to any one of claims 1 to 7,
A stacking step of forming a stacked body in which the dielectric film and a sacrificial layer which is a material for forming the post member are alternately stacked on the substrate;
A hole forming step of forming a plurality of holes penetrating from the upper surface of the laminate to the substrate surface;
A post forming step of etching the sacrificial layer in a predetermined range centered on the hole and forming the post member by the remaining sacrificial layer;
A method for producing a wavelength tunable interference filter comprising: A method for manufacturing a wavelength tunable interference filter according to any one of claims 1 to 7,
A stacking step of forming a stacked body in which the dielectric film and a sacrificial layer that can be removed by etching are alternately stacked on the substrate;
A hole forming step of forming a plurality of holes penetrating from the upper surface of the laminate to the substrate surface;
A post member embedding step of embedding the post member in the hole;
A sacrificial layer removing step of etching and removing the sacrificial layer;
A method for producing a wavelength tunable interference filter comprising: A method for manufacturing a wavelength tunable interference filter according to any one of claims 1 to 7,
A sacrificial layer forming step of forming a sacrificial layer provided with a hole for forming a post member, and a dielectric layer forming step of covering the sacrificial layer and forming a dielectric layer in the hole and on the surface of the sacrificial layer , By repeating a plurality of times, a laminating step of forming a laminated body in which a plurality of the sacrificial layers and the dielectric layers are laminated on the substrate;
A sacrificial layer removing step of removing the sacrificial layer by etching;
A method of manufacturing a wavelength tunable interference filter, comprising:

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