JP6754464B2 - Tunable optical filter - Google Patents

Description

The present invention relates to a technical field of a tunable optical filter and a method for manufacturing a tunable optical filter using the interference effect of light.

As this kind of optical filter, one using the principle of Fabry-Perot interferometer is known. The Fabry-Perot interferometer is a simple interferometer that uses the interference effect of multiple reflected light, and the incident light repeats multiple reflections between two opposing reflective films, resulting in a wavelength that corresponds to the length of the optical path. The light of the band can be selectively extracted.

Patent Document 1 proposes an optical filter formed by joining two substrates having an optical film. In an optical filter having such a configuration, it is required to control the gap between optical films with high accuracy in order to improve the wavelength resolution. Specifically, for example, when joining two substrates, it is important to ensure parallelism without tilting each substrate.

Japanese Unexamined Patent Publication No. 2012-145675

In the technique described in Patent Document 1, bonding of substrates is realized by applying a load in a state where two substrates are bonded together. However, when a load is applied to a flat substrate, an unnecessary pressure distribution may occur. Unnecessary pressure distribution causes, for example, bending or tilting of the substrate, resulting in a technical problem that the performance of the optical filter is deteriorated.

For unnecessary pressure distribution, for example, it is conceivable to take measures on the joining device side using jigs, etc., but not only is the jigs, etc. required to have high processing accuracy, but also the jigs and substrates when a load is applied It is not easy to align the jigs.

Examples of the problems to be solved by the present invention include the above. An object of the present invention is to provide a wavelength tunable optical filter and a method for manufacturing a wavelength tunable optical filter capable of reducing unnecessary pressure distribution at the time of substrate bonding.

The variable wavelength optical filter that solves the above problems is provided on the first substrate, the second substrate facing the first substrate, the first reflective film provided on the first substrate, and the second substrate. A second reflective film facing the first reflective film via a gap between the reflective films, and a joint portion for joining the first substrate and the second substrate are provided, and the first substrate is the first reflective film. On the first load surface on the side opposite to the surface on which is provided, a part of the portion overlapping the joint portion intersects the first load surface rather than the end portion of the first substrate on the first load surface. is formed as a first protrusion protruding toward said first projection, in plan view in the direction intersecting with the first load surface, the first substrate so as to surround the first reflecting film The second substrate is formed , and a part of the portion overlapping the joint portion on the second load surface on the side opposite to the surface on which the second reflective film is provided is the second load surface on the second load surface. It is formed as a second protruding portion that protrudes from the end of the two substrates in the direction intersecting the second load surface .

The method for manufacturing a variable wavelength optical filter that solves the above problems is a first reflective film forming step of forming a first reflective film on a first substrate and a second reflective film forming step of forming a second reflective film on a second substrate. And, on the load surface of the first substrate opposite to the surface on which the first reflective film is provided, all or a part of the portion overlapping the joint with the second substrate is the other portion of the load surface. The step of forming a protruding portion that is formed as a protruding portion that protrudes in a direction that intersects the substrate surface, and the first substrate and the second substrate have a gap between the first reflective film and the second reflective film. It is provided with a joining step of joining so as to face each other.

It is sectional drawing which shows the structure of the tunable optical filter which concerns on Example. It is a top view which shows the structure of the upper surface part and the lower surface part of the tunable light filter which concerns on Example. It is sectional drawing which shows the structure of the tunable optical filter which concerns on a comparative example. It is a top view which shows the structure of the upper surface part and the lower surface part of the tunable light filter which concerns on a comparative example. It is sectional drawing which shows the bonding method of the tunable optical filter which concerns on a comparative example. It is a top view which shows the pressure distribution at the time of joining of the tunable optical filter which concerns on a comparative example. It is sectional drawing which shows the bonding method of the tunable optical filter which concerns on Example. It is a comparative figure which shows the merit in the size of the tunable optical filter which concerns on Example. It is sectional drawing which shows the structure of the tunable optical filter which concerns on 1st modification. It is a top view and sectional view which shows the structure of the tunable light filter which concerns on 2nd modification. It is a top view and sectional view which shows the structure of the tunable optical filter which concerns on 3rd modification. It is a top view and sectional view which shows the structure of the tunable light filter which concerns on 4th modification. It is a top view and sectional view which shows the structure of the tunable light filter which concerns on 5th modification. It is a top view and sectional view which shows the structure of the tunable optical filter which concerns on 6th modification. It is sectional drawing (the 1) which shows the structure of the tunable optical filter which concerns on 7th modification. It is sectional drawing (the 2) which shows the structure of the tunable optical filter which concerns on 7th modification. It is sectional drawing (the 3) which shows the structure of the tunable optical filter which concerns on 7th modification.

<1>
The variable wavelength optical filter according to the present embodiment is provided on the first substrate, the second substrate facing the first substrate, the first reflective film provided on the first substrate, and the second substrate. A second reflective film facing the first reflective film via a gap between the reflective films and a joint portion for joining the first substrate and the second substrate are provided, and the first substrate is the first reflective film. On the load surface on the side opposite to the surface on which the is provided, all or a part of the portion overlapping the joint portion is formed as a projecting portion protruding in a direction intersecting the substrate surface with respect to other portions on the load surface. ..

The wavelength tunable optical filter according to the present embodiment includes a first substrate provided with a first reflective film and a second substrate provided with a second reflective film. The first reflective film and the second reflective film are composed of a material having a high reflectance for light in a desired frequency band (for example, Ag, etc.), and are formed by using a technique such as sputtering. .. The first substrate and the second substrate are joined at the joint portion by, for example, bonding with a resin, activation bonding, or the like. The first substrate and the second substrate are joined so that the first reflective film and the second reflective film are arranged so as to face each other with a gap between the reflective films. The gap between the reflective films may be appropriately set according to the wavelength band of the light to be extracted.

When joining the first substrate and the second substrate, for example, a load is applied by a joining machine. Specifically, it is opposite to the surface of the first substrate and the second substrate on which the first reflective film and the second reflective film are provided by the joining machine installed so as to sandwich the first substrate and the second substrate which are overlapped with each other. A load is applied to the load surface on the side. At this time, if a load is simply applied, an unnecessary pressure distribution may occur on the load surface. Unnecessary pressure distribution causes, for example, bending or tilting of the substrate, and as a result of impairing the parallelism between the first reflective film and the second reflective film, the performance of the optical filter is deteriorated.

However, in the present embodiment, a protrusion is formed on the first substrate to reduce unnecessary pressure distribution. Specifically, all or a part of the portion overlapping the joint portion of the load surface is formed so as to project in a direction intersecting the substrate surface (that is, a load application direction) with respect to other portions on the load surface. The "portion that overlaps the joint portion" here means a region that overlaps the joint portion when the first substrate is viewed in a plane, and is a portion that greatly contributes to the load on the joint portion.

According to the configuration described above, the protruding portion is pushed out in the load applying direction relative to the other portion (in other words, the other portion is pushed down in the load applying direction relative to the protruding portion). Unnecessary pressure distribution due to load application can be reduced. Further, in the present embodiment, since adjustment on the joining machine side is not particularly required, jig processing accuracy and accuracy of alignment between the jig and the substrate are not required, and unnecessary pressure distribution can be reduced extremely easily.

The same effect can be obtained even when a third substrate is arranged between the first substrate and the second substrate. That is, even when the number of substrates to be joined increases, the effect according to the present embodiment can be obtained accordingly.

As described above, according to the tunable optical filter according to the present embodiment, it is possible to prevent deterioration of quality by reducing the deflection and inclination of the substrate due to the application of a load at the time of joining.

<2>
In one aspect of the wavelength tunable optical filter according to the present embodiment, the second substrate has all or a part of the portion overlapping the joint portion on the load surface on the side opposite to the surface on which the second reflective film is provided. , It is formed as a protruding portion protruding in the direction intersecting the substrate surface with respect to other portions on the load surface.

According to this aspect, in addition to the first substrate, a protrusion is formed on the load surface of the second substrate. Therefore, unnecessary pressure distribution can be reduced when the load is applied from both sides of the first substrate and the second substrate. Therefore, the deflection and inclination of the substrate can be reduced more effectively.

<3>
In the embodiment in which the protrusion is also formed on the second substrate described above, the protrusion of the first substrate and the protrusion of the second substrate have the same shape when viewed in a plane in the direction intersecting the substrate surface. It may be.

According to this aspect, since the protruding portion of the first substrate and the protruding portion of the second substrate have the same shape (that is, the same region of the load surface is projected), unnecessary pressure distribution can be reduced. , Efficient load application can be realized. In addition, the "same shape" in the present embodiment does not mean only when the shapes are completely the same, but also includes shapes that are close to being the same. That is, even if the shapes of the protruding portion of the first substrate and the protruding portion of the second substrate are not completely the same, the effects of the above-described embodiment can be appropriately exhibited as long as they have similar shapes.

<4>
In another aspect of the tunable optical filter according to the present embodiment, the projecting portion is circular or annular when viewed in a plane in a direction intersecting the substrate surface.

According to this aspect, since the protrusion is circular or annular, the pressure applied to the substrate can be effectively dispersed. Therefore, the unnecessary pressure distribution can be effectively reduced.

<5>
In another aspect of the tunable optical filter according to the present embodiment, at least one of the first substrate and the second substrate has a movable portion that makes the first reflective film or the second reflective film movable. The movable portion is formed so as to be lower than the protruding portion in the direction intersecting the substrate surface.

According to this aspect, the position of the first reflective film or the second reflective film can be adjusted by a movable portion. The movable portion (specifically, the substrate portion provided with the movable mechanism) is formed so as to be lower in the direction intersecting the substrate surface than the protruding portion. In other words, the movable portion is formed so as not to protrude in the load application direction like the protruding portion.

According to the above configuration, almost no pressure is applied to the moving portion even when a load is applied. Therefore, it is possible to prevent the movable portion, which is required to be adjusted with high accuracy, from being adversely affected by the pressure when the load is applied. In addition, it is possible to prevent the movable portion from being unexpectedly damaged when a load is applied due to foreign matter or the like on the movable portion.

<6>
In another aspect of the tunable optical filter according to the present embodiment, the first substrate and the second substrate have the same shape when viewed in a plane in the direction intersecting the substrate surface, and are rotated by a predetermined angle. It is joined with.

According to this aspect, although the first substrate and the second substrate have the same shape, they are joined in a state of being rotated by a predetermined angle, so that they are not joined in a state where they overlap each other exactly, and compared with other parts. Therefore, there are parts that are relatively susceptible to load deformation. Specifically, the edges and corners of the first substrate and the second substrate are provided, but by providing the protruding portions on the first substrate and the second substrate, the load on the relatively easily deformable portion is applied. Can be reduced and unnecessary pressure distribution can be reduced. Therefore, it is possible to reduce the deflection and inclination of the substrate due to the application of a load at the time of joining, and it is possible to prevent the deterioration of quality.

<7>
In another aspect of the tunable optical filter according to the present embodiment, the first substrate and the second substrate have different shapes when viewed in a plane in a direction intersecting the substrate surface.

According to this aspect, since the first substrate and the second substrate have different shapes, they are not joined in a state where they overlap each other, and a portion that is relatively easily load-deformed as compared with other portions is generated. Specifically, the edges and corners of the first substrate and the second substrate are provided, but by providing the protruding portions on the first substrate and the second substrate, the load on the relatively easily deformable portion is applied. Can be reduced and unnecessary pressure distribution can be reduced. Therefore, it is possible to reduce the deflection and inclination of the substrate due to the application of a load at the time of joining, and it is possible to prevent the deterioration of quality.

<8>
In another aspect of the tunable optical filter according to the present embodiment, the position of the protruding portion is determined based on the internal structure between the first substrate and the second substrate.

According to this aspect, since the position (in other words, the shape) of the protruding portion is determined based on the internal structure between the first substrate and the second substrate, unnecessary pressure distribution can be effectively reduced. .. Specifically, for example, by discriminating a place where pressure is likely to be applied, a place where pressure is not easily applied, or the like by a preliminary simulation that reproduces the internal structure, the optimum load application pattern according to the internal structure can be determined. Then, if the position of the protruding portion is determined so that the optimum load application pattern can be realized, the unnecessary pressure distribution can be reduced extremely effectively.

<9>
The method for manufacturing the variable wavelength optical filter according to the present embodiment includes a first reflective film forming step of forming a first reflective film on a first substrate and a second reflective film forming step of forming a second reflective film on a second substrate. And, on the load surface of the first substrate opposite to the surface on which the first reflective film is provided, all or a part of the portion overlapping the joint with the second substrate is the other portion of the load surface. The step of forming a protruding portion that is formed as a protruding portion that protrudes in a direction that intersects the substrate surface, and the first substrate and the second substrate have a gap between the first reflective film and the second reflective film. It is provided with a joining step of joining so as to face each other.

According to the method for manufacturing a tunable optical filter according to the present embodiment, an unnecessary pressure distribution when a load is applied can be reduced by providing a protrusion on the first substrate as in the case of the tunable optical filter described above. Therefore, the deflection and inclination of the substrate due to the application of a load at the time of joining are reduced, and it is possible to prevent the deterioration of quality.

The order in which the steps of the present embodiment are executed is not particularly limited, and the steps may be executed one after the other or in parallel. Therefore, for example, the protrusion forming step may be executed before the first reflective film forming step and the second reflective film forming step are executed.

In the method for manufacturing the tunable optical filter according to the present embodiment, it is possible to adopt various aspects similar to the various aspects of the tunable optical filter according to the above-described embodiment.

<10>
In one aspect of the method for manufacturing a tunable optical filter according to the present embodiment, in the projecting portion forming step, the projecting portion is formed by etching the first substrate.

According to this aspect, by processing the surface of the substrate by etching, a protrusion having a desired shape can be formed relatively easily.

<11>
In another aspect of the method for manufacturing a tunable optical filter according to the present embodiment, in the projecting portion forming step, the projecting portion is formed by integrally molding a photosensitive resin material on the first substrate.

According to this aspect, the protrusion can be formed by integrally molding the photosensitive resin material without directly processing the surface of the substrate.

The operation and other gains of the tunable optical filter and the method for manufacturing the tunable optical filter according to the present embodiment will be described in more detail in the following examples.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

<Device configuration>
First, the apparatus configuration of the tunable optical filter according to the embodiment will be described with reference to FIGS. 1 to 4. Here, FIG. 1 is a cross-sectional view showing the configuration of the tunable optical filter according to the embodiment, and FIG. 2 is a plan view showing the configurations of the upper surface portion and the lower surface portion of the tunable light filter according to the embodiment. Further, FIG. 3 is a cross-sectional view showing the configuration of the tunable light filter according to the comparative example, and FIG. 4 is a plan view showing the configurations of the upper surface portion and the lower surface portion of the tunable light filter according to the comparative example.

In FIGS. 1 and 2, the wavelength tunable optical filter 10 according to this embodiment includes a first substrate 100 and a second substrate 200.

The first substrate 100 has a movable portion 110. The movable portion 110 is supported by a membrane portion 120 located around the movable portion 110. A first reflective film 130 and a first driving electrode 140 are provided on the second substrate 200 side of the movable portion 110. Further, in this embodiment, in particular, a protruding portion 150 of the first substrate is provided around the membrane portion 120 on the load surface of the first substrate 100.

The second substrate 200 is joined to the first substrate 100 at the joint portion 400. A second reflective film 210 and a second driving electrode 220 are provided at positions of the second substrate 200 facing the movable portion 100. Further, similarly to the first substrate 100, a protruding portion 230 of the second substrate is provided on the load surface of the second substrate 200.

The first reflective film 130 and the second reflective film 210 are configured to contain a material having a high reflectance such as Ag (silver), and the first substrate 100 and the second substrate 200 are formed by using a technique such as sputtering. Formed on top. The first reflective film 130 and the second reflective film 210 are arranged so as to face each other with a predetermined gap G. The gap G may be appropriately set according to the wavelength band of the light targeted by the tunable light filter.

The first drive electrode 140 and the lower electrode 220 function as an electrostatic actuator by applying a voltage. Therefore, the gap G between the first reflective film 130 and the second reflective film 210 can be finely adjusted by changing the electric power applied to the first driving electrode 140 and the lower electrode 220.

The protruding portion 150 of the first substrate and the protruding portion 230 of the second substrate have a structure that protrudes from other portions of the load surface (specifically, peripheral portions of the four corners of the substrate). In the following, the configurations of the protrusion 150 of the first substrate and the protrusion 230 of the second substrate will be described in more detail with reference to a comparative example in which the protrusion 150 of the first substrate and the protrusion 230 of the second substrate are not provided. ..

In FIGS. 3 and 4, in the wavelength tunable optical filter 20 according to the comparative example, the load surfaces of the first substrate 100 and the second substrate 200 are flat except for the membrane portion 120. That is, the height of the first substrate 100 is the same everywhere except the membrane portion 120. Further, since the membrane portion 120 does not exist on the second substrate 200, the height of the second substrate 200 is the same everywhere.

Returning to FIGS. 1 and 2, the wavelength tunable optical filter 10 according to the present embodiment is configured so that the height around the four corners of the substrate is lower than that of the above-mentioned comparative example. In other words, the height near the center of the substrate is configured to be higher than the height around the four corners of the substrate. As described above, in the wavelength tunable optical filter 10 according to the present embodiment, the first substrate 100 and the second substrate 200 are provided with the protrusion 150 of the first substrate and the protrusion 230 of the second substrate, so that the load surface can be affected. A part is configured to protrude as compared with the other part.

The protrusion 150 of the first substrate and the protrusion 230 of the second substrate can be formed by, for example, processing the surfaces of the first substrate 100 and the second substrate 200 by etching or the like. Alternatively, the photosensitive resin material may be formed by integrally molding the first substrate 100 and the second substrate 200.

<Problems at the time of joining>
Next, a method of joining the tunable optical filter according to the comparative example and problems that may occur at the time of joining will be described with reference to FIGS. 5 and 6. Here, FIG. 5 is a cross-sectional view showing a method of joining the wavelength tunable optical filter according to the comparative example. Further, FIG. 6 is a plan view showing a pressure distribution at the time of joining the wavelength tunable optical filter according to the comparative example.

In FIG. 5, when a general tunable optical filter is manufactured, a load is applied by the joining machine 500 in a state where the first substrate 100 and the second substrate 200 are overlapped at the joining portion 400. At this time, it is desirable that pressure is evenly applied to the first substrate 100 and the second substrate 200 in order to maintain the parallelism of the first reflective film 130 and the second reflective film 210. However, in the substrate shape such as the tunable optical filter 20 according to the comparative example, it is extremely difficult to apply the pressure evenly, and a portion where the pressure is concentrated (the portion surrounded by the broken line in the figure) is generated to some extent. It ends up. The unnecessary pressure distribution causes the substrate to bend or tilt, and as a result, the performance of the optical filter deteriorates.

As shown in FIG. 6, according to the research by the inventor of the present application, it has been found that the pressure at the time of applying a load tends to be concentrated around the four corners of the substrate. In this embodiment, in order to reduce such an unnecessary pressure distribution, a protrusion 150 of the first substrate and a protrusion 230 of the second substrate are provided.

<Effect of this example>
Next, the effects exhibited by the tunable optical filter according to the embodiment will be described with reference to FIGS. 7 and 8. Here, FIG. 7 is a cross-sectional view showing a method of joining the wavelength tunable optical filter according to the embodiment. Further, FIG. 8 is a comparative diagram showing merits in size of the tunable optical filter according to the embodiment.

In FIG. 7, according to the tunable optical filter 10 according to the present embodiment, when a load is applied, the portion mainly corresponding to the protruding portion 150 of the first substrate and the protruding portion 230 of the second substrate (that is, the broken line in the figure). Pressure is applied to the enclosed area. That is, this embodiment has a structure in which pressure is less likely to be applied to the periphery of the four corners of the substrate as compared with the comparative example in which pressure is likely to be applied to the periphery of the four corners of the substrate. As a result, unnecessary pressure distribution when a load is applied can be reduced. Therefore, it is possible to avoid a situation in which the parallelism of the first reflective film 130 and the second reflective film 210 cannot be maintained due to the deflection or inclination of the substrate.

As a method for reducing unnecessary pressure distribution, it is conceivable to change the configuration on the joining machine 500 side. Specifically, for example, an example in which the load application surface of the joining machine 500 is made convex can be considered. However, when the configuration on the joining machine 500 side is changed, not only high processing accuracy is required for the joining machine 500, but also there arises a technical problem that the alignment between the joining machine 500 and the substrate becomes very difficult. This embodiment has the effect of avoiding such inconveniences and preferably avoiding unnecessary pressure distribution.

In FIG. 8, as another method for reducing unnecessary pressure distribution, for example, a method of making the shape of the entire substrate circular (see the second comparative example in the figure) can be considered. However, if the entire substrate is made circular, the size of the substrate becomes large, as can be seen from the figure. As described above, this embodiment has an effect that it is also advantageous in miniaturization of the substrate (and by extension, the element after joining).

<Modification example>
Next, a modified example of the wavelength tunable optical filter according to the embodiment will be described with reference to FIGS. 9 to 17. Here, FIG. 9 is a cross-sectional view showing the configuration of the wavelength tunable optical filter according to the first modification, and FIG. 10 is a top view and a cross-sectional view showing the configuration of the tunable light filter according to the second modification. .. 11 is a top view and a cross-sectional view showing the configuration of the tunable optical filter according to the third modification, and FIG. 12 is a top view and a cross-sectional view showing the configuration of the tunable light filter according to the fourth modification. Is. Further, FIG. 13 is a top view and a cross-sectional view showing the configuration of the wavelength tunable optical filter according to the fifth modification, and FIG. 14 is a top view and a cross-sectional view showing the configuration of the tunable light filter according to the sixth modification. Is. 15 to 17 are cross-sectional views showing the configuration of the tunable optical filter according to the seventh modification, respectively.

In FIG. 9, the wavelength tunable optical filter according to the first modification is configured so that the height of the movable portion 110 on the first substrate 100 is lower than that of the protruding portion 150 of the first substrate. With this configuration, even if a foreign object is present on the movable portion 110, it is possible to prevent the movable portion 110 from being damaged by applying a load.

In FIG. 10, in the wavelength tunable optical filter according to the second modification, the first substrate 100 and the second substrate 200 having the same shape are joined in a state of being rotated by a predetermined angle (for example, 45 degrees). At the time of joining, the first substrate 100 and the second substrate 200 do not overlap, and a portion (that is, a portion circled in the figure) that is relatively susceptible to load deformation as compared with other portions is generated. According to the above, it is possible to reduce the load applied to a portion that is relatively easily deformed and reduce unnecessary pressure distribution. In FIG. 11, in the wavelength tunable optical filter according to the third modification, the first substrate 100 and the second substrate 200 having different shapes are joined. At the time of joining, the first substrate 100 and the second substrate 200 do not overlap, and there is a portion (that is, the portion circled in the figure) that is relatively easily deformed by the load as compared with the other portions. According to the second modification, the load applied to the portion where the load is relatively easily deformed can be reduced, and the unnecessary pressure distribution can be reduced.

In FIG. 12, in the wavelength tunable optical filter according to the fourth modification, the shape of the protruding portion 150 of the first substrate is determined according to the internal structure. When the location where pressure is likely to be applied or is difficult to apply is known in advance from the internal structure, the shape of the protrusion 150 of the first substrate is determined so that the optimum load application pattern can be realized, and more preferably unnecessary pressure is applied. The distribution can be reduced.

In FIG. 13, in the wavelength tunable optical filter according to the fifth modification, only the protruding portion 230 of the second substrate is provided on the second substrate 200, and the protruding portion 150 of the first substrate is provided on the first substrate 100. Not provided. As described above, even when the protruding portion is provided on only one of the substrates, the effect of the above-described embodiment is appropriately exhibited.

In FIG. 14, in the wavelength tunable optical filter according to the sixth modification, the third substrate 300 is arranged between the first substrate 100 and the second substrate 200. In this way, even when three or more substrates are joined by applying a load, the protrusion 150 of the first substrate and the protrusion 230 of the second substrate are formed on the load surfaces of the first substrate 100 and the second substrate 200. If provided, the effects of the above-described embodiment will be exhibited accordingly.

In FIGS. 15 to 17, in the wavelength tunable optical filter according to the seventh modification, the shape of the protruding portion 150 of the first substrate and the shape of the protruding portion 230 of the second substrate are the same. That is, the same portion (that is, the overlapping region) of the first substrate 100 and the second substrate 200 is configured to protrude. With this configuration, pressure can be applied more preferably when a load is applied.

In the example shown in FIG. 15, the size of the protruding portion 150 of the first substrate and the protruding portion 230 of the second substrate and the size of the joint portion 400 are equal to each other. Further, in the example shown in FIG. 16, the sizes of the protruding portion 150 of the first substrate and the protruding portion 230 of the second substrate are smaller than the size of the joint portion 400. In the example shown in FIG. 17, the size of the protrusion 150 of the first substrate and the protrusion 230 of the second substrate is larger than the size of the joint portion 400. In any of these cases, the effects of the present embodiment described above are appropriately exhibited.

As described above, according to the tunable optical filter according to the embodiment, it is possible to reduce unnecessary pressure distribution when a load is applied by projecting a part of the load surface. Therefore, deterioration in quality due to bending or tilting of the substrate can be suitably prevented.

The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope of claims and within a range not contrary to the gist or idea of the invention that can be read from the entire specification, and the tunable light with such a modification. A method for manufacturing a filter and a tunable optical filter is also included in the technical scope of the present invention.

10 Variable wavelength optical filter 100 1st substrate 110 Movable part 120 Membrane part 130 1st reflective film 140 1st driving electrode 150 Protruding part of 1st substrate 200 2nd substrate 210 2nd reflective film 220 2nd driving electrode 230 2nd substrate Projection 300 Third board 400 Joining 500 Joining machine 600 Foreign matter G Gap

Claims (3)

A first substrate,
The second substrate facing the first substrate and
The first reflective film provided on the first substrate and
A second reflective film provided on the second substrate and facing the first reflective film via a gap between the reflective films,
A joint portion for joining the first substrate and the second substrate is provided.
In the first substrate, a part of the portion overlapping the joint portion on the first load surface on the side opposite to the surface on which the first reflective film is provided is the first substrate on the first load surface. It is formed as a first protruding portion that protrudes from the end portion in the direction intersecting the first load surface.
The first protruding portion is formed on the first substrate so as to surround the first reflective film when viewed in a plane in a direction intersecting the first load surface .
In the second substrate, a part of the portion overlapping the joint portion on the second load surface on the side opposite to the surface on which the second reflective film is provided is the second substrate on the second load surface. A tunable optical filter characterized in that it is formed as a second protruding portion that protrudes from the end portion in a direction intersecting the second load surface . The tunable light according to claim 1 , wherein the first protruding portion and the second protruding portion have the same shape when viewed in a plane in a direction intersecting the first load surface. filter. The tunable optical filter according to claim 1 or 2 , wherein the first protruding portion is circular or annular when viewed in a plane in a direction intersecting the first load surface.