JP2016212164A - Manufacturing method of optical functional film, manufacturing method of spatial optical modulation element, optical functional film, and spatial optical modulation element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical functional film that suppresses a reduction in accuracy of a fine structure.SOLUTION: There is provided a manufacturing method of an optical functional film including: a first step S202 of forming through holes 210a in a light receiving part 210 formed on a substrate P and forming a gap part 212 on the periphery of the light receiving part 210; and a second step S204 of performing thermal oxidation treatment of heating the substrate P after the first step S202.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an optical functional film manufacturing method, a spatial light modulation element manufacturing method, an optical functional film, and a spatial light modulation element.

In recent usage forms of imaging devices, it is often required to acquire not only an image of a subject but also spatial information such as a distance and a viewing direction.
The following techniques are known as techniques capable of acquiring such spatial information. This is a technique for acquiring information on the space and the incident angle of a light beam incident on an image sensor by performing a decoding process based on Fourier transform using the image sensor and a spatial light modulator on which an encoded aperture pattern is formed ( For example, see Patent Document 1).

  Such a spatial light modulator is required to have an optical functional film that achieves both high light utilization efficiency and a highly accurate fine structure.

  For the production of a fine structure having a high aspect ratio, a Si material capable of obtaining a large etching rate ratio with a mask material (for example, SiO 2) in an etching process is suitable. On the other hand, Si materials are opaque in the visible wavelength region, and are difficult to use for transmission optical elements. Therefore, a technique is known in which the patterned Si is subjected to a thermal oxidation treatment and the composition is changed to transparent SiO 2 to be used as an optical element.

In the manufacturing method in which Si is processed by dry etching in the research process of the present inventor, when performing thermal oxidation treatment for changing the composition to SiO 2, distortion of the microstructure occurs due to volume expansion, and the optical functional film The present inventors have recognized problems that flatness is not maintained or that the optical functional film is damaged.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for manufacturing an optical functional film that suppresses a decrease in the precision of a fine structure.

  In order to solve the above-described problem, a method for manufacturing an optical functional film according to the present invention includes a first step of forming a through hole in a light receiving portion formed on a substrate and forming a gap around the light receiving portion. And a second step of performing a thermal oxidation treatment for heating the substrate after the first step.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the optical function film which suppresses the fall of the precision of a fine structure can be provided.

It is a figure which shows an example of the whole structure of the imaging device and imaging module in the 1st Embodiment of this invention. It is a perspective view which shows an example of a structure of the spatial light modulation element in the 1st Embodiment of this invention. It is a figure which shows an example of a structure of the encoding opening part shown in FIG. It is a top view which shows an example of a structure of the unit film | membrane structure shown in FIG. It is sectional drawing which shows another example of a structure of the encoding opening part shown in FIG. It is a schematic diagram which shows an example of operation | movement of the spatial light modulation element shown in FIG. It is a flowchart which shows an example of a process of the manufacturing method of the spatial light modulation element shown in FIG. It is a figure which shows typically an example of each process of the manufacturing method shown in FIG. It is an electron micrograph which shows an example of the spatial light modulation element manufactured with the manufacturing method shown in FIG. It is a figure which shows an example of a structure of the encoding opening part in the 2nd Embodiment of this invention. It is an electron micrograph figure which shows an example of the encoding opening part in the 2nd Embodiment of this invention. It is a figure which shows an example of a structure of the encoding opening part in the 3rd Embodiment of this invention. It is a figure which shows an example of a structure of the encoding opening part in the 4th Embodiment of this invention. It is an electron micrograph figure which shows an example of the encoding opening part in the 4th Embodiment of this invention. It is a figure which shows an example of a structure of the encoding opening part in the 5th Embodiment of this invention. It is an electron micrograph figure which shows an example of the encoding opening part in the 5th Embodiment of this invention. It is a figure which shows an example of a structure of the encoding opening part in the 6th Embodiment of this invention. It is a figure which shows an example of a structure of the encoding opening part in the 7th Embodiment of this invention. It is a figure which shows the structure of the conventional encoding opening part.

The imaging apparatus 1 shown in FIG. 1 in the present embodiment includes an imaging module 2 for acquiring an image, and an imaging optical system 3 that is an optical system that forms an incident light beam and emits it toward the imaging module 2. And have.
The imaging device 1 also includes a mirror 4 for selecting an optical path from the imaging optical system 3, a finder 6 for confirming the field of view, and a deflecting element 5 as a prism for deflecting light from the mirror 4 to the finder 6. , A shutter 8 for adjusting the exposure time, and a control unit 9 for controlling the exposure time, imaging conditions, and the like.
The above-described configuration other than the imaging module 2 is the same as that of a general single-lens reflex camera. However, a so-called mirrorless single-lens reflex configuration may be adopted in which the finder 6 and the mirror 4 are removed and a liquid crystal monitor is provided instead.
In the following description, the optical axis direction of the light beam that passes through the imaging optical system 3 and enters the imaging module 2 is the upward Z axis, and the Y axis and the X axis perpendicular to the Z axis are as shown by the arrows in FIG. Determined and used for explanation. In the present embodiment, the Z direction coincides with the vertically upward direction, but may be appropriately changed according to the arrangement direction of the imaging device 1.

The imaging module 2 includes a spatial light modulation element 21 as a coded aperture element that emits a spatially modulated incident light beam, and an imaging element 22 that acquires the spatially modulated light flux as image information. And a spacer 23 for connecting the image sensor 22 and the spatial light modulator 21.
The imaging module 2 also has wiring 25 that electrically connects the imaging module 2 and the control unit 9.

The imaging optical system 3 limits the amount of light incident on the imaging module 2 and the imaging lens group 30 provided with at least one lens, which is arranged to form an image on the imaging element 22. The aperture 7 is provided.
The imaging optical system 3 is disposed so as to form an image on the image pickup element 22 with the light beam incident on the image pickup apparatus 1. In other words, it is arranged so that the focal point is located on the image pickup element 22 on the + Z direction side, which is upstream of the image pickup module 2 in the optical axis direction.

  The control unit 9 performs coding angle generation means for applying spatial modulation to the light flux, and performs space separation such as distance and direction as will be described later based on image information obtained by the image sensor 22. It has a function as a decoding processing means for obtaining an image including information and a machine control means for controlling a mechanical member included in the imaging apparatus 1.

The image sensor 22 is an image sensor using a CCD (Charge Coupled Device) as a photodetector that acquires, as image information, a light beam that has been spatially modulated by the spatial light modulator 21. The imaging element 22 has a photodetector array 22a as an imaging surface in which photodiodes as light receiving elements as a plurality of photodetectors are arranged, and converts information such as the intensity of incident light flux into an electrical signal. To do. Although the CCD is used here, a CMOS (Complementary Metal-Oxide Semiconductor) sensor or the like may be used as long as the image sensor can acquire image information.
The imaging element 22 is installed on the −Z direction side of the spatial light modulation element 21 with the photodetector array 22a facing the + Z direction side.

The spacer 23 is a member that is in contact with the image sensor 22 and is in contact with the downstream side of the spatial light modulator 21 in the Z-axis direction, and maintains the distance d between the spatial light modulator 21 and the image sensor 22. To do.
Here, the spacer 23 is a member that is independent from the spatial light modulator 21 and the image sensor 22, but the spacer 23 may be a step structure provided on one or both of the spatial light modulator 21 and the image sensor 22. good.

  As shown in FIG. 2, the spatial light modulator 21 has a coded opening 21 a that is an optical functional film that changes the incident light beam and applies spatial modulation.

As shown in an enlarged view in FIG. 2, the encoding opening 21 a includes a unit film structure 210 that is a light receiving section that is arranged in a plane and forms a transmission type light receiving surface, and an adjacent unit film structure 210. 1st support part 211 which is a support structure arranged between.
As shown in FIG. 3A, the encoding opening 21 a connects and supports the gap 212 formed around the unit film structure 210, the first support part 211, and the unit film structure 210. And a second support portion 213.

As shown in FIG. 3B, the spatial light modulation element 21 is formed on the bottom of the liquid reservoir 214 and a liquid reservoir 214 that is formed in the lower part of the unit film structure 210 and holds the liquid L. And the upper electrode 216 which is an electrode portion provided in contact with the unit film structure 210.
In addition, the AA 'cross section of Fig.3 (a) was used here as FIG.3 (b).

As shown in FIG. 4, the unit film structure 210 includes a through-hole 210 a that is a fine structure formed so as to penetrate the unit film structure 210, and a transparent wall member 210 b.
The through-hole 210a is a cylindrical cavity with a height of 20 μm arranged so that circular holes with a diameter of 1 μm form a dense structure when viewed from the Z direction.
In addition, the height of the through hole 210a is desirably 5 to 20 μm in order to sufficiently reduce the amount of transmitted light when blocking light.
Wall member 210b is a transparent member constituting the wall surfaces of the through holes 210a, as described below, to be created with transparentizable member by easily processable and thermal oxidation process, such as SiO ₂ desirable.
The upper electrode 216 is a transparent electrode provided on the side wall surface of the through hole 210 a, and moves the liquid L up and down by a voltage V applied between the upper electrode 216 and the lower electrode 215. As a material of the upper electrode 216, it is desirable to use a transparent conductive film such as ITO (Indium Tin Oxide).

The second support part 213 shown in FIG. 3A is connected to the four corners which are the peripheral parts of each unit film structure 210, and is a connecting member that connects the first support part 211 and the unit film structure 210. It is.
The second support portion 213 has at least one end connected to the apex if the XY cross section of the unit film structure 210 is a polygon, and to the peripheral edge if the XY cross section of the unit film structure 210 is a unit film structure. 210 may be supported.

  The gap 212 is a space surrounded by the unit film structure 210, the second support 213, and the first support 211, and when the thermal oxidation process described later is performed, the area of the gap 212 is small. The stress is buffered by changing with expansion of any or all of the unit film structure 210, the second support part 213, and the first support part 211.

The liquid reservoir 214 is a hollow container attached to the end of the through hole 210a in the −Z direction, in other words, the lower end. It is desirable that the volume of the liquid reservoir 214 is sufficiently large with respect to the total volume of the through holes 210a.
Here, the liquid reservoir 214 is drawn in a mode of being directly connected to the through-hole 210a. However, as shown in FIG. 5, the liquid reservoir 214 is arranged in the −X direction of the unit film structure 210 in the spatial light modulator 21. A liquid introduction path 214 a that is provided on the side and connects the liquid reservoir 214 and the −Z direction end of the through hole 210 a may be attached.
In such a configuration, the fluid L is held by the liquid reservoir 214 and the liquid introduction path 214 a and is guided to the through hole 210 a by the voltage V between the upper electrode 216 and the lower electrode 215.

The liquid L is a liquid that is held by the liquid reservoir 214 and is adjusted to have a refractive index close to that of the wall surface member 210b, and the value of the voltage V applied between the upper electrode 216 and the lower electrode 215. Accordingly, the through hole 210a is infiltrated by the electrowetting phenomenon.
As the liquid L, an electrolytic solution is used from the viewpoint of conductivity. The liquid L may be a non-electrolytic solution.
The liquid L functions as a refractive index matching means by flowing into the through hole 210a. Here, the liquid L does not necessarily need to be a liquid, and a substance having both a fluid property and a function as a refractive index matching means, such as a so-called sol-gel, may be used.

The spatial light modulator 21 forms a coded aperture pattern, in other words, a mosaic pattern, by discretely changing the transmittance of the unit film structure 210 by the control unit 9 to spatially modulate the incident light beam. Is granted. At this time, the control unit 9 has a function as coding pattern generation means.
Here, the spatial light modulation element 21 is a spatial light modulation element that changes the transmittance by controlling the position of the liquid L whose refractive index is matched with the through-hole 210a by the electrowetting phenomenon.

A method for acquiring an image using the imaging apparatus 1 having such a configuration will be described.
The light beam incident on the imaging device 1 is deflected by the imaging lens group 30 so as to form an image on the imaging element 22, passes through the diaphragm 7, is limited in light quantity, and passes through the imaging optical system 3. To do.
The light beam that has passed through the imaging optical system 3 enters the spatial light modulator 21 and is spatially modulated by the encoding aperture 21a.
The control unit 9 serving as a coding pattern generation unit controls the transmittance distribution of the coding opening 21a using a spatial transmittance distribution obtained by superimposing a plurality of sinusoidal waveforms having different periods.
At this time, the minimum unit capable of controlling the transmittance distribution is the unit film structure 210, and the transmittance of the unit film structure 210 changes according to the amount of the liquid L infiltrating into the through hole 210a.

The fluctuation of the transmittance of the unit film structure 210 will be described.
FIG. 6 is a diagram schematically showing the operation of the liquid L in each unit film structure 210 when the voltage V is applied.
First, in the non-energized state of V = 0 shown in FIG. 6A, a gas G such as air exists in the through hole 210a. That is, the unit film structure 210 is in a state in which the refractive index is not matched, so that irregular reflection occurs at the interface between the gas G and the wall surface member 210b and the transmittance is low.

Next, the suction state of V = V1 is shown in FIG. In the suction state, since the voltage V1 is applied between the upper electrode 216 and the lower electrode 215, the wall surface of the through hole 210a changes to hydrophilic.
Since the through-hole 210a is a fine capillary, when the inner wall changes to hydrophilic, a suction force acts on the liquid L due to a capillary phenomenon, and the liquid L flows into the through-hole 210a. That is, the liquid level of the liquid L, which is the interface between the liquid L and the gas G, rises inside the through hole 210a.
The gas G present inside the through-hole 210a in the non-energized state moves in the + Z direction through the gas discharge path in the suctioned state.
As described above, since the liquid L is a fluid whose refractive index is adjusted so that the unit film structure 210 becomes transparent when the through-hole 210a is filled, the liquid L flows into the through-hole 210a. The volume of the region having the refractive index difference is reduced, and the refractive index matching is achieved. That is, the scattered light at the interface between the gas G and the wall surface member 210b is reduced and the transmittance is improved.
At this time, the transmittance of the unit membrane structure 210 is determined by the amount of the liquid L flowing into the through-hole 210a, in other words, the height of the liquid L.

  When V = Vmax, that is, when the through-hole 210a is filled with the liquid L, the unit membrane structure 210 is in a transmissive state in which the transmittance is maximum. At this time, the gas G may be discharged from an exhaust port connected to the outside.

Alternatively, the encoding opening 21a may be configured to connect the upper part of the liquid reservoir 214 to the gas discharge path in the case where the liquid reservoir 214 is provided in the lateral direction as shown in FIG. .
With such a configuration, the permeability varies as the gas G circulates between the liquid reservoir 214 and the unit membrane structure 210, so that the entry of substances that adversely affect the semiconductor material, such as external moisture, can be prevented. Suppresses deterioration.

The encoding aperture 21a changes the transmittance in each unit film structure 210 on the element in accordance with the electrical signal from the control unit 9 serving as the encoding pattern generation means, in other words, the periodic modulation signal as described above. An encoded aperture pattern is formed.
That is, the spatial light modulator 21 applies spatial modulation to the light beam passing through the spatial light modulator 21 by periodically changing the transmittance of each unit film structure 210 on the element.

When forming an encoded pattern using such a spatial transmittance distribution, the spatial frequency position corresponding to the period of the sine wave, that is, the horizontal axis when Fourier transform is performed, the finite space of the image itself. The spectral distribution of the frequency band is replicated in the form of a convolution integral.
That is, the spatial frequency spectrum distribution of the subject is duplicated on the spatial frequency axis by the number of periods of the sine waveform. Here, depending on the magnitude of the frequency of the sine waveform, the angle information is mixed, so that the angle of view can be separated.

In the present embodiment, four-dimensional information including space and angle information from two-dimensional image information using image information on which a modulation signal is superimposed, coding pattern information, and decoding processing means, That is, the light field can be reconfigured.
Here, the angle originally desired to be acquired is the angle of the light beam reaching the imaging apparatus 1 from the subject, but from the incident angle of the light beam deflected by the imaging optical system 3 and incident on the image sensor 22 to the photodetector array 22a, Since it is easy to derive the angle, the incident angle to the photodetector array 22a is defined as an angle component hereinafter.
However, a detailed description of the method for calculating parallax information from a plurality of angle-of-view separation images will be omitted as appropriate.

First, the control unit 9 as an encoding pattern generation unit generates an arbitrary encoding pattern. The control unit 9 acquires an image using the generated arbitrary encoding pattern, and extracts a plurality of field angle separation information.
Next, the control unit 9 analyzes the image information subjected to the angle-of-view separation, and calculates distance information for the local position of the subject as a specific target in the image. Using the distance information calculated by such a method, the control unit 9 as a distance resolution determination unit determines whether or not a desired resolution is obtained in the obtained image.
When the resolution of the obtained image is insufficient, the control unit 9 as the spatial light modulation pattern generation unit recalculates the cycle of the sine wave constituting the spatial light modulation pattern.
The control unit 9 changes the angle of view separation resolution based on the calculated spatial light modulation pattern, thereby generating the spatial light modulation pattern again and acquiring a new image.
The control unit 9 optimizes the distance resolution by forming such a feedback loop, and finally obtains a distance image suitable for the target subject.

A method of forming a through-hole 210a by dry etching using a material that can be easily processed, such as a Si substrate, and then modifying it to SiO ₂ by heating and oxidation in forming an optical functional film that transmits a light beam Can be considered.
However, according to the research of the inventors, only by using such a method, the unit film structure 210 is vertically moved in the Z direction as shown by the contrast of the SEM image in FIG. 19 by the thermal oxidation process after fine processing. It has been found that distortion occurs.
In the spatial light modulation element 21 having such a configuration, if the unit film structure 210 is strained up and down in the Z direction, there is a concern that it may be out of the design value and sufficient accuracy cannot be obtained.
Such distortion is caused by the fact that the unit film structure 210 includes fine through-holes 210a and wall surface members 210b, so that the volume expansion proceeds in the XY plane direction, while the first support portion 211 expands in the XY plane direction. Since the amount is small, it is considered that the difference in the internal stress is caused to release up and down in the Z direction.

In the present embodiment, by providing the gap portion 212 shown in FIG. 3A around the unit film structure 210, the occurrence of distortion in the Z direction in the thermal oxidation treatment process is reduced.
A method of forming a large number of fine through holes 210a on a substrate P, which is a Si substrate, by a method using photolithography and dry etching will be described with reference to FIGS. FIG. 7 is a flowchart of the process, and FIG. 8 is a schematic diagram schematically showing the transition of the deformation of the substrate P by the process.

First, as shown in FIG. 8A, a masking process for forming a mask of an oxide film (SiO ₂ ) on the substrate P by photolithography is performed (step S201 shown in FIG. 7). This masking process is performed so as to cover the + Z side end of the wall surface member 210b in FIG. 5 and to make the through hole 210a a gap.

Next, as shown in FIG. 8B, a high-aspect ratio structure having a difference in the Z direction on the surface by using a difference in etching rate between Si and SiO ₂ by a dry etching apparatus such as a Deep-RIE apparatus, In other words, a dry etching process, which is a first process for creating a concavo-convex structure, is performed (step S202 shown in FIG. 7).
By such a dry etching process, the gap 212 and the through hole 210a are formed. At this time, the first support part 211 and the second support part 213 are also formed.
As shown in FIG. 8C, the back side etching process is performed to remove the Si on the back side with the same dry etching apparatus using the surface on which the high aspect ratio structure is formed as the front side (step S203 shown in FIG. 7).

As shown in FIG. 8D, the substrate P is baked at 800 to 1100 ° C. in an oxygen atmosphere to perform a thermal oxidation treatment process as a second process (step S204 shown in FIG. 7).
The unit film structure 210 having the through hole 210a and the gap 212 formed in the dry etching process is formed by modifying the Si substrate into the SiO ₂ substrate by the thermal oxidation process.

In the thermal oxidation process shown in step S204, the four corners of the unit film structure 210 are supported by the second support part 213 as already shown in FIG.
A gap 212 is provided at the peripheral edge of the unit film structure 210. Therefore, as shown in FIG. 9, in the thermal oxidation process, the area of the gap 212 is reduced, so that the distortion of the unit film structure 210 in the Z direction is suppressed.
With the configuration in which the gap portion 212 is provided in the peripheral portion of the unit film structure 210, the gap portion 212 avoids warping of the film surface of the unit film structure 210 and maintains the flatness of the unit film structure 210. That is, a decrease in the precision of the fine structure of the unit film structure 210 is suppressed.
Further, since the gap 212 is formed in the periphery so as not to overlap with the unit film structure 210 in the Z direction, the area through which the light beam is transmitted is minimized, and the influence on the transmittance of the unit film structure 210 is reduced. .

In the present embodiment, a dry etching process (Step S202) in which a plurality of through holes 210a are formed in the unit film structure 210 formed on the substrate P, and a gap 212 is formed around the unit film structure 210, And a thermal oxidation treatment step (step S204) for heating the substrate P after the etching treatment step.
By performing the thermal oxidation treatment step after the dry etching treatment step for forming the voids 212 in the unit film structure 210, a reduction in the precision of the fine structure in the thermal oxidation treatment step is suppressed.

Moreover, in this embodiment, the area of the space | gap part 212 changes in a thermal oxidation process.
The stress generated in the thermal oxidation process is wasted due to the change in the area of the air gap 212 serving as a buffer, thereby reducing the influence on the transmittance of the unit film structure 210 while suppressing the decrease in the precision of the fine structure. To do.

In the present embodiment, the encoded opening 21 a includes the unit film structure 210, the through-hole 210 a formed in the unit film structure 210, the gap 212 formed around the unit film structure 210, and the unit film structure 210. And a second support portion 213 for supporting the.
Further, the second support part 213 is connected to the peripheral part of the unit film structure 210.
With such a configuration, the reduction in the precision of the fine structure is suppressed while the influence on the transmittance of the unit film structure 210 is reduced.

  Further, in the present embodiment, the encoding opening 21a includes a first support portion 211 in which a plurality of unit film structures 210 are arranged side by side and arranged between adjacent unit film structures 210. . The second support part 213 connects the first support part 211 and the peripheral part.

A second embodiment of the present invention will be described.
Note that, in each embodiment described below, portions common to the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

In the second embodiment, as shown in FIGS. 10A and 10B, the second support portion 213 is a beam portion 217 a that is a beam structure extending from the first support portion 211. The beam portion 217a is connected to the unit film structure 210 at the connection position N1, and both ends of the beam portion 217a are fixed to the first support portion 211.
FIG. 10B is a cross-sectional view taken along the line AA ′ shown in FIG. 10A, and is a target cross-section showing the positional relationship between the unit film structure 210 and the first support portion 211 in the Z direction. Since it is a figure, description of the liquid reservoir 214 and the lower electrode 215 is omitted. The same applies to other embodiments described later.
The beam portion 217a has a function as a buffer member that relaxes the deformation of the first support portion 211 and the deformation of the unit film structure 210 by the deformation of the beam portion 217a in the thermal oxidation process (step S204). doing.
With this configuration, in the thermal oxidation process (step S204), the beam portion 217a is bent around the position N1 connected to the unit film structure 210 as shown in FIG. Thus, a decrease in accuracy of the fine structure is suppressed.
For the convenience of the thermal oxidation process, the beam portion 217a is preferably made of the same material as the substrate P, but may be formed of a flexible member, for example, in order to further relieve stress.

In the third embodiment, as shown in FIG. 12, the second support portion 213b is a beam portion 217b in which the first support portion 211 and the unit film structure 210 are connected by a plurality of beam structures.
The beam portion 217b is configured such that one end portion is fixed to the first support portion 211 and the other end portion is connected to the unit film structure 210 in the vicinity of the four corners of the unit film structure 210. The unit film structure 210 is supported by connecting the unit 211 and the unit film structure 210.
That is, the second support portion 213b has a shape that is likely to be deformed at the other end portion of the beam portion 217b to which stress is applied in the thermal oxidation process.

In this manner, by providing a plurality of beam portions 217b and providing a portion where the beam portions 217b are easily deformed, damage such as bending of the beam portions 217b is suppressed.
With this configuration, damage to the beam portion 217b at the time of creation is avoided while suppressing a decrease in precision of the fine structure.
In addition, the yield at the time of creating the encoded opening 21a is improved.

In the fourth embodiment, as shown in FIG. 13, the second support portion 213c forms a beam portion 217c.
The beam portion 217c includes a first beam portion 218 and a second beam portion 219 that are orthogonal to each other at the bent portion N2.
As described above, the bent portion N2 is provided in the beam portion 217c, and a portion where the beam portion 217c is easily deformed is provided, thereby preventing breakage such as bending of the beam portion 217c.

The first beam portion 218 and the second beam portion 219 have a deflection function for deflecting the deformation of the unit film structure 210 in the outer peripheral direction due to the stress in the rotation direction on the XY plane.
With this configuration, even when a compressive stress in the diagonal direction of the unit film structure 210 is generated, the shape of the gap 212 changes as shown in FIG. 14 and the unit film structure 210 rotates on the XY plane. Thus, warpage due to compressive stress is avoided.
Further, with such a configuration, by providing a portion where the beam portion 217c is easily deformed, damage such as bending of the beam portion 217c is suppressed, and the yield at the time of creating the encoded opening 21a is improved.
With this configuration, an optical functional film having a flat and high transmittance modulation width is provided while suppressing a decrease in the precision of the fine structure.

In the fifth embodiment, as shown in FIGS. 15 and 16, the second support portion 213 d has a central portion O <b> 1 that is a first support portion fixed to the spatial light modulation element 21, and is centered. There are four beam portions 217d connected to the four unit film structures 210 adjacent from the portion O1.
Each beam portion 217d forms a criss-cross structure arranged by being rotated 90 degrees, and is connected to the unit film structure 210 at each end.
In other words, one side of the unit film structure 210 connected to the beam portion 217d and the beam portion 217d in the longitudinal direction are connected to each other in parallel.

With such a configuration, the unit film structure 210 is supported without providing the mesh-like first support portion 211, so that the light shielding region is reduced and the effective area of the unit film structure 210 is increased.
Furthermore, it provides an optical functional film that is flat and has a high transmittance modulation width while suppressing a decrease in precision of the fine structure.

In the sixth embodiment, as shown in FIG. 17, the second support portion 213e has a center portion O2 that is a first support portion fixed to the spatial light modulation element 21, and the center portion O2 And four beam portions 217e connected to the four unit film structures 210 adjacent to each other.
Each beam portion 217e includes a plurality of third beam portions 230 orthogonal to the diagonal direction of the unit film structure 210, and a plurality of fourth beam portions 231 parallel to the A direction that is the diagonal direction of the encoding opening 21a. ,have.
The beam portion 217e has a shape in which the third beam portion 230 and the fourth beam portion 231 are alternately connected.
Further, the junction N3 between the third beam portion 230 and the fourth beam portion 231 is a bent portion.

With this configuration, deformation of the unit film structure 210 in the rotation direction is suppressed, and warping in the A direction is suppressed.
With such a configuration, the unit film structure 210 is supported without providing the mesh-like first support portion 211, so that the light shielding region is reduced and the effective area of the unit film structure 210 is increased.
Furthermore, it provides an optical functional film that is flat and has a high transmittance modulation width while suppressing a decrease in precision of the fine structure.

In the seventh embodiment, as shown in FIG. 18, the unit film structure 210 is formed by continuously connecting the end portions of the wall surface of the beam portion 217f.
That is, the beam portion 217f is a member having a fractal shape that configures the wall surface of the through hole 210a and connects the central portion O3 and the unit film structure 210.
Therefore, the encoding opening 21a has a fractal-shaped gap 212f inside the unit film structure 210 at the periphery of the portion where the through hole 210a of the unit structure film 210 as a light receiving part is formed. .
The first support portion 211f fixes the end portions of a plurality of adjacent unit film structures 210 that are adjacent to each other.
With this configuration, the gap 212f absorbs deformation due to volume expansion together with the unit film structure 210, thereby ensuring the flatness of the unit film structure 210.

  Furthermore, a flat spatial light modulation element having a high transmittance and a high transmittance modulation width can be obtained by a configuration including the gap 212f having a fractal shape and the unit film structure 210 surrounded by the holes 212f. create.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

  For example, the above-described optical functional film is used in the encoding opening of the spatial light modulator, but can be applied to various other active light functional members and fuel cell members.

  Further, the control unit may be provided inside the imaging module, or may be provided in the imaging apparatus separately from the imaging module.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 1 Imaging device 2 Imaging module 3 Optical system (imaging optical system)
9 Control Unit 21 Spatial Light Modulator 21a Optical Functional Film (Encoded Opening)
22 Image sensor 22a Photodetector array 23 Spacer 25 Wiring 210 Light receiving part (unit film structure)
210a Through-hole 210b Wall end (wall member)
211 1st support part 212,212f Cavity part 213,213a-213f 2nd support part 214 Liquid holding | maintenance part (liquid reservoir part)
216 Electrode (upper electrode)
217a-f Beam structure (beam part)
L Fluid (liquid)
N2, N3 bent portion P, substrate S202, first process (dry etching process)
S204 Second step (thermal oxidation treatment step)
V Voltage X Optical axis and vertical direction Y Optical axis and vertical direction Z Optical axis direction

JP2008-191661

Claims (16)

A first step of forming a through hole in a light receiving portion formed on a substrate and forming a gap around the light receiving portion;
A second step of performing a thermal oxidation treatment for heating the substrate after the first step;
The manufacturing method of the optical functional film which has this. A method for producing an optical functional film according to claim 1,
The method for producing an optical functional film, wherein the gap portion changes an area of the gap portion in the second step. It is a manufacturing method of the optical functional film according to claim 1 or 2,
In the first step, a plurality of the light receiving units, a first support unit disposed between the plurality of light receiving units,
A second support portion connecting the light receiving portion and the first support portion;
A method for producing an optical functional film, characterized by comprising: It is a manufacturing method of the optical function film according to claim 3,
The method for manufacturing an optical functional film, wherein the second support portion has a beam structure. It is a manufacturing method of the optical functional film according to claim 4,
The method for producing an optical functional film, wherein the second support part supports a peripheral part of the light receiving part. It is a manufacturing method of the optical functional film according to claim 4 or 5,
The method of manufacturing an optical functional film, wherein the beam structure is linear. It is a manufacturing method of the optical functional film according to claim 4 or 5,
The beam structure includes a bent portion, and the method for manufacturing an optical functional film. A through hole is formed in the light receiving portion formed on the substrate,
A first step of forming a gap inside the light receiving portion;
A second step of performing a thermal oxidation treatment for heating the substrate after the first step;
The manufacturing method of the optical functional film which has this. An optical functional film; an electrode portion formed in contact with the light receiving portion; a fluid penetrating into the through hole according to a voltage applied to the electrode portion; and a fluid holding portion for holding the fluid. In the manufacturing method of the spatial light modulator having
The method for manufacturing a spatial light modulator according to claim 1, wherein the method for manufacturing the optical functional film is the method according to claim 1. A light receiving portion formed on the substrate;
A through hole formed in the light receiving portion;
A gap formed around the light receiving portion;
A second support part for supporting the light receiving part;
Have
The second support part is an optical functional film connected to a peripheral part of the light receiving part. The optical functional film according to claim 10,
A plurality of the light receiving parts are arranged in a plane,
A first support portion disposed between the adjacent light receiving portions;
The optical support film, wherein the second support part connects the first support part and the peripheral part. The optical functional film according to claim 10 or 11,
The optical function film, wherein the second support portion has a beam structure that deforms in response to a stress generated in the light receiving portion. The optical functional film according to claim 12,
The optical functional film, wherein the beam structure is linear. The optical functional film according to claim 12,
The beam functional structure has a bent portion, the optical functional film. A light receiving portion formed on the substrate;
A through hole formed in the light receiving portion;
A gap formed inside the light receiving part;
An optical functional film. The optical functional film according to any one of claims 10 to 15,
An electrode portion formed in contact with the light receiving portion;
A fluid penetrating into the through hole in accordance with a voltage applied to the electrode portion;
A fluid holding part for holding the fluid;
A spatial light modulator.

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