JP6766579B2 - Manufacturing method of optical device and optical device - Google Patents

Description

The present invention relates to an optical device using structural colors and a method for manufacturing the optical device.

Structural colors such as morpho butterfly scales and jade skin are different from the colors that are visible due to electron transitions in molecules, such as the colors exhibited by pigments, and are different from the colors that are visible due to electron transitions in molecules, such as light diffraction, interference, and scattering. It is a color that is visually recognized by the action of an optical phenomenon caused by the structure. For example, the structural color due to multi-layer film interference is a structural color generated by the interference of light in a specific wavelength range reflected at each interface of the multi-layer film. In this way, since light in a specific wavelength range can be extracted by multilayer interference, the principle of multilayer interference makes it possible to select wavelengths by selectively transmitting or reflecting light in a specific wavelength range. It is used in optical devices.

However, the wavelength range that can be extracted by multi-layer film interference depends on the layer structure such as the film thickness of each layer in the multi-layer film. Therefore, in an optical device using multi-layer film interference, different layers are used for each wavelength range to be selected. It is necessary to form a multilayer film having a structure. Therefore, the manufacturing process of the optical device differs greatly depending on the selected wavelength range, so that the versatility is poor, and the manufacturing process of the optical device having a plurality of regions in which the selected wavelength ranges are different from each other is very complicated. I have no choice but to become.

As an optical device that selects wavelengths by an optical phenomenon different from multilayer film interference, an optical device using a waveguide mode resonance phenomenon has been proposed. This optical device has a sub-wavelength grating that is a diffraction grating that is arranged at a period smaller than the wavelength of light. When light is incident on the sub-wavelength lattice, the emission of diffracted light into the space on the incident side is suppressed, while light in a specific wavelength range propagates while being multiple-reflected, causing resonance and light in this specific wavelength range. Wavelength mode resonance phenomenon occurs in which is strongly emitted as reflected light.

For example, the color filter described in Patent Document 1 has a structure in which a plurality of convex portions forming a sub-wavelength lattice are arranged on a substrate. However, in a device having such a structure, in order to increase the intensity of the extracted light, that is, to obtain reflected light or transmitted light having excellent wavelength selectivity, as described in Patent Document 1, the substrate is made of synthetic quartz. It is desirable to secure a large difference in the refractive index between the substrate and the convex portion by forming the convex portion from silicon and reduce the loss due to multiple reflection of light propagating in the sub-wavelength lattice region. For that purpose, it is necessary to use an SOQ (Silicon on Quartz) substrate in which single crystal Si is formed on a substrate made of synthetic quartz, which causes an increase in manufacturing cost.

On the other hand, the wavelength selection element described in Patent Document 2 has a waveguide layer formed of a material having a higher refractive index than the material constituting the substrate between the substrate and the convex portion constituting the sub-wavelength lattice. have. According to such a structure, even when the convex portion and the waveguide layer are formed of resin, the wavelength selectivity of the light emitted from the element is enhanced by propagating the multiple reflected light into the waveguide layer. Be done. Further, since the nanoimprint method can be used as a method for forming the convex portion and the waveguide layer from the resin, it is possible to easily manufacture the device while reducing the material cost, and the manufacturing cost can also be reduced. ..

Japanese Patent No. 5023324 Japanese Unexamined Patent Publication No. 2009-25558

However, in the structure of Patent Document 2, since the light propagation mode in the waveguide layer is mainly determined by the thickness of the waveguide layer and the wavelength of light, light in a desired wavelength range is multiplely reflected in the waveguide layer. In order to cause resonance, it is necessary to precisely control the film thickness of the waveguide layer. Forming a waveguide layer having a precise film thickness in addition to a convex portion having a fine period imposes a heavy load on the manufacture of an optical device. For example, when the convex portion and the waveguide layer are formed by the nanoimprint method, they are pressed against the resin material in order to form the convex portion in the resin material coated on the base material in the manufacturing process. Since the residual film portion sandwiched between the intaglio plate and the base material forms the waveguide layer, it is difficult to precisely control the thickness of the waveguide layer.

Therefore, as an optical device that emits light in a wavelength range selected by utilizing the waveguide mode resonance phenomenon, an optical device having excellent wavelength selectivity and a structure that is easy to manufacture is desired.

An object of the present invention is to provide a manufacturing method capable of easily manufacturing an optical device having enhanced wavelength selectivity, and an optical device manufactured by this manufacturing method.

A method for manufacturing an optical device that solves the above problems is a method for manufacturing an optical device composed of a material that transmits incident light, and a plurality of methods that are arranged on the surface of a layer made of a first low refractive index material at sub-wavelength periods. A plurality of concave portions that are alternately arranged with the convex portions along the direction in which the plurality of convex portions are arranged, and have an area equal to the area of the plurality of convex portions when viewed from a direction facing the surface. The first step of forming the concavo-convex structure layer having the convex portion and the concave portion by forming the concave portion of the above, and using a high refractive index material having a higher refractive index than the first low refractive index material. A second step of forming a high refractive index layer having a thickness smaller than the height of the convex portion on the surface of the concave-convex structure layer, wherein the high refractive index layer is located on the concave portion. A second step of forming a layer including a sub-wavelength lattice and a second sub-wavelength lattice located on the convex portion and having the same lattice period as the first sub-wavelength lattice, the uneven structure layer and the height. By forming an embedded layer made of a second low refractive index material having a refractive index lower than that of the high refractive index material on the surface of the structure made of the refractive index layer, the unevenness of the structure is made the second It includes a third step of filling the sub-wavelength lattice with the second low refractive index material.

When light is incident on the optical device manufactured by the above manufacturing method, a waveguide mode resonance phenomenon occurs in a region including each of the two sub-wavelength lattices. Then, the light in a specific wavelength region that leaks out in the process of multiple reflection in one region and enters the other region propagates while being multiple reflected in the other region, and is propagated from the optical device in each of the two regions. The light in the above-mentioned specific wavelength range enhanced by is emitted as reflected light. Then, among the incident light, light in a wavelength range other than the enhanced wavelength range is transmitted through the optical device and emitted as transmitted light. Therefore, according to the optical device having the above configuration, the intensity of the light in the specific wavelength region emitted as the reflected light is higher than that of the optical device having only one sub-wavelength lattice. That is, according to the above manufacturing method, the wavelength selectivity of the optical device is enhanced without requiring precise control of the film thickness of the layer in contact with the sub-wavelength lattice, so that the optical device with enhanced wavelength selectivity can be easily produced. Can be manufactured in.

In the above manufacturing method, in the first step, the concave plate is pressed against the coating layer made of the resin which is the first low refractive index material, the resin is cured, and then the concave plate is released to remove the unevenness of the concave plate. By transferring to the resin, the uneven structure layer is formed, and in the second step, the high refractive index layer is formed by using a material containing an inorganic compound as the high refractive index material, and the third step. Then, the embedded layer may be formed by applying a resin which is the second low refractive index material to the surface of the structure and curing the applied resin.

According to the above manufacturing method, since the concave-convex structure layer is formed by using the nanoimprint method, the uneven structure layer having fine irregularities can be preferably and easily formed.

In the above manufacturing method, in the third step, the two structures are opposed to each other so that the high refractive index layers face each other, and the region between the two structures is filled with the second low refractive index material. May form the embedded layer.

According to the above manufacturing method, an optical device having four or more sub-wavelength lattices can be easily manufactured. According to such an optical device, it is possible to further enhance the wavelength selectivity and increase the degree of freedom in adjusting the wavelength range included in the reflected light and the transmitted light.

The optical device that solves the above problems is an optical device made of a material that transmits incident light, and includes a plurality of first high refractive index portions constituting the first sub-wavelength lattice and the first high refractive index portion. It has a plurality of first low refractive index portions having a lower refractive index than, and the first high refractive index portion and the first low refractive index portion are arranged along the direction in which the first high refractive index portions are arranged. A first lattice region located alternately, a plurality of second high refractive index portions composed of the same material as the first high refractive index portion to form a second sub-frequency lattice, and the second high refractive index portion. It has a plurality of second low refractive index portions having a lower refractive index than, and the second high refractive index portion and the second low refractive index portion are arranged along the direction in which the second high refractive index portions are arranged. The first low refractive index region and the second low refractive index region, each of which has a second lattice region located alternately, and a refractive index lower than each of the average refractive index of the first lattice region and the average refractive index of the second lattice region. A refractive index region and a third low refractive index region are provided, and the first lattice region includes the first low refractive index region and the second low refractive index region in the thickness direction of the first lattice region. The second lattice region is sandwiched between the second low refractive index region and the third low refractive index region in the thickness direction of the second lattice region, and the lattice period of the first sub-frequency lattice is sandwiched between the two. And the lattice periods of the second sub-wavelength lattice are equal periods to each other, and the volume ratio of the plurality of first high refractive index portions in the first lattice region and the plurality of firsts in the second lattice region. The volume ratio of the two high refractive index portions is the same, and the first high refractive index portion and the second low refractive index portion overlap when viewed from the direction along the thickness direction of the first lattice region. The second high refractive index portion and the first low refractive index portion overlap each other.

According to the above configuration, each lattice region of the first lattice region and the second lattice region has a sub-wavelength lattice, and each lattice region has a low refractive index lower than the refractive index of each lattice region. Since it is sandwiched between the refractive index regions, when light is incident on each lattice region, the emission of diffracted light into the incident side space is suppressed in each lattice region, and a waveguide mode resonance phenomenon occurs. Since the lattice period of each lattice region and the volume ratio of the high refractive index portion are the same, the wavelength region of light that causes resonance in the first lattice region and the wavelength region of light that causes resonance in the second lattice region are Match.

Therefore, the light in a specific wavelength region that leaks out in the process of multiple reflection in one lattice region and enters the other lattice region propagates while being multiple reflected in the other lattice region, and is first transmitted from the optical device. The reflected light in the wavelength region enhanced in the lattice region and the reflected light in the wavelength region enhanced in the second lattice region are emitted. Then, among the incident light, light in a wavelength range other than the enhanced wavelength range is transmitted through the optical device and emitted from the optical device.

As described above, according to the optical device having the above configuration, the light in the wavelength region enhanced in each of the two lattice regions is obtained as the reflected light, so that the light is reflected as compared with the optical device having only one lattice region. The intensity of light in the specific wavelength range emitted as light increases. That is, since the wavelength selectivity is enhanced without requiring precise control of the film thickness of the layer in contact with the lattice region, easy production is possible.

In the above configuration, the first low refractive index region, the first low refractive index portion, and the portion of the second low refractive index region adjacent to the first low refractive index portion are continuous with each other. It is a first structure which is one structure, and is adjacent to the third low refractive index region, the second low refractive index portion, and the second low refractive index portion in the second low refractive index region. The portion to be used may be a second structure which is one structure which is continuous with each other.
According to the above configuration, since the portion which is one structure can be manufactured in one step by using the above-mentioned manufacturing method, an optical device can be easily manufactured.

In the above configuration, the difference in refractive index between the first structure and the first high refractive index portion and the second high refractive index portion is larger than 0.2, and the second structure and the first high refractive index are The difference in refractive index between the portion and the second high refractive index portion may be larger than 0.2.

According to the above configuration, the waveguide mode resonance phenomenon is likely to occur favorably in each lattice region, and the intensity of the reflected light from each lattice region is further enhanced. Therefore, the wavelength selectivity in the optical device is further enhanced.

In the above configuration, the material constituting the first structure is any of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin, and the material constituting the second structure is ultraviolet curable. The material which is any of a resin, a thermosetting resin, and a thermoplastic resin and which constitutes the first high refractive index portion and the second high refractive index portion may contain an inorganic compound.

According to the above configuration, the waveguide mode resonance phenomenon is likely to occur favorably in each lattice region, and the intensity of the reflected light from each lattice region is further enhanced. Therefore, the wavelength selectivity in the optical device is further enhanced. Further, it is possible to reduce the material cost required for manufacturing the optical device and to apply a simple manufacturing method such as the nanoimprint method.

In the above configuration, the second low refractive index region has the first high refractive index portion and the third high refractive index portion made of the same material as the second high refractive index portion, and the third high refractive index portion. The refractive index portion is the second low between the ends of the first high refractive index portion and the second high refractive index portion that are adjacent to each other when viewed from the direction along the thickness direction of the first lattice region. It may extend along the thickness direction of the refractive index region.

According to the above configuration, it is possible to form a high refractive index portion by using a vacuum vapor deposition method, and it is possible to form a suitable sub-wavelength lattice. Even in this case, the configuration of the second low refractive index region for causing the waveguide mode resonance phenomenon is preferably realized.

In the above configuration, the plurality of first high refractive index portions, the plurality of first low refractive index portions, the plurality of second high refractive index portions, and the plurality of second low refractive index portions are common. It may have a shape extending in a band shape in one direction.

According to the above configuration, it is easy to match the lattice period of the sub-wavelength lattice and the volume ratio of the first high refractive index portion in each lattice region. Moreover, the production of the sub-wavelength lattice is easy.

In the above configuration, a portion composed of the first lattice region, the second lattice region, the first low refractive index region, the second low refractive index region, and the third low refractive index region is a resonance structure portion. The optical device may include a plurality of the resonance structures arranged along the thickness direction of the resonance structure.

According to the above configuration, since the optical device includes four or more lattice regions, the wavelength selectivity of the optical device is further enhanced, and the degree of freedom in adjusting the wavelength range included in the reflected light and the transmitted light is increased. Is possible.

In the above configuration, the lattice periods of the first sub-wavelength lattice and the second sub-wavelength lattice of each of the plurality of resonance structure portions may be the same in the plurality of resonance structure portions.

According to the above configuration, the wavelength ranges of the light that causes resonance in each lattice region are the same. Therefore, when the light is incident on the optical device, the light in the specific wavelength range that is multiple-reflected in the upper lattice region is multiplexed. The light leaking from this lattice region in the process of reflection enters the underlying lattice region and is multiple-reflected, and this phenomenon is repeated as many times as the number of lattice regions. As a result, the reflected light in a specific wavelength region enhanced in each lattice region is emitted from the optical device, so that the intensity of the light in the specific wavelength region emitted as the reflected light becomes higher, and the wavelength of the reflected light is increased. The selectivity is further enhanced.

In the above configuration, the plurality of resonance structure portions include a first resonance structure portion and a second resonance structure portion, and the first sub-wavelength lattice and the second sub-wavelength lattice of the first resonance structure portion. The lattice period of the above and the lattice periods of the first sub-wavelength lattice and the second sub-wavelength lattice of the second resonance structure may be different from each other.

According to the above configuration, the wavelength range of light that resonates in each lattice region of the first resonance structure and the wavelength range of light that resonates in each lattice region of the second resonance structure are mutually exclusive. different. Therefore, when light is incident on the optical device, light in a specific wavelength range is multiple-reflected in each lattice region of the upper resonance structure portion, and light in a wavelength region that is not multiple-reflected is transmitted through this resonance structure portion. Then, it enters the lower resonance structure and light in a wavelength range different from that of the upper resonance structure is repeatedly reflected in each lattice region of the lower resonance structure. As a result, from the optical device, the light in the first wavelength region enhanced in the lattice region of the first resonance structure portion and the light in the second wavelength region enhanced in the lattice region of the second resonance structure portion. Reflected light including light is emitted. Further, among the wavelength ranges included in the light incident on the optical device, the light in the wavelength range other than the first wavelength range and the second wavelength range emitted as the reflected light is emitted as transmitted light. Therefore, in the optical device, it is possible to widen the wavelength range included in the reflected light and narrow the wavelength range included in the transmitted light while increasing the intensity of the reflected light. Therefore, the degree of freedom in adjusting the hue observed as reflected light or transmitted light can be increased by setting the lattice period of the sub-wavelength lattice of each resonance structure.

In the above configuration, in each of the plurality of resonance structure portions, the plurality of first high refractive index portions, the plurality of first low refractive index portions, the plurality of second high refractive index portions, and the plurality of firsts. The element portion, which is each of the two low refractive index portions, has a shape extending in a band shape in one direction, and the plurality of resonance structure portions include a first resonance structure portion and a second resonance structure portion. The extending direction of the element portion of the first resonance structure portion and the extending direction of the element portion of the second resonance structure portion may be different from each other.

According to the above configuration, in the lattice region of each resonance structure portion, among the light contained in the incident light, the light polarized in the direction corresponding to the arrangement direction of the sub-wavelength lattice causes resonance. Since the arrangement directions of the sub-wavelength lattices are different between the first resonance structure portion and the second resonance structure portion, the lattice region of the first resonance structure portion and the lattice region of the second resonance structure portion are included in the incident light. Of the light, the light polarized in different directions resonates and is emitted from each resonance structure. Therefore, the reflected light is efficiently emitted from the incident light containing the polarized light components in various directions, so that the intensity of the reflected light is further increased.

According to the present invention, an optical device having enhanced wavelength selectivity can be easily manufactured.

The figure which shows the cross-sectional structure of an optical device, and the planar structure of a lattice region about 1st Embodiment of an optical device. The figure which shows the formation process of the concavo-convex structure layer about 1st Embodiment of the manufacturing method of an optical device. The figure which shows the formation process of the high refractive index layer about 1st Embodiment of the manufacturing method of an optical device. The figure which shows the formation process of the embedded layer about 1st Embodiment of the manufacturing method of an optical device. FIG. 5 is a cross-sectional view showing a configuration example of a second low refractive index region in the optical device of the first embodiment. The cross-sectional view which shows the modification of the optical device of 1st Embodiment. The cross-sectional view which shows the modification of the optical device of 1st Embodiment. The figure which shows the operation of the wavelength selection filter which is an application example of the optical device of 1st Embodiment. The figure which shows the planar structure of the display body which is an application example of the optical device of 1st Embodiment. The figure which shows the operation of the display body which is an application example of the optical device of 1st Embodiment. The figure which shows the planar structure of the color filter which is an application example of the optical device of 1st Embodiment. The figure which shows the operation of the color filter which is an application example of the optical device of 1st Embodiment. FIG. 5 is a cross-sectional view showing an example of the cross-sectional structure of the optical device according to the second embodiment of the optical device. FIG. 5 is a cross-sectional view showing an example of the cross-sectional structure of the optical device according to the second embodiment of the optical device. The figure which shows the state which the concavo-convex structure faces each other about the 2nd Embodiment of the manufacturing method of an optical device. The figure which shows the formation process of the embedded layer about 2nd Embodiment of the manufacturing method of an optical device. A perspective view showing a perspective structure of an optical device according to a third embodiment of the optical device. FIG. 3 is a perspective view showing the optical device divided into regions for the third embodiment of the optical device. The plan view which shows the planar structure of the lattice region in the optical device of a modification. The perspective view which shows the perspective structure of the concave-convex structure layer in the optical device of a modification. The figure which shows the sub-wavelength lattice pattern of Example 2 in a simplified manner.

(First Embodiment)

A method for manufacturing an optical device and a first embodiment of the optical device manufactured by this manufacturing method will be described with reference to FIGS. 1 to 7. The optical device has a function of extracting light in a specific wavelength range from the light incident on the optical device by reflecting or transmitting it. The wavelength range to be selected by the optical device is not particularly limited, but for example, the optical device extracts light in a specific wavelength range from light that can be visually recognized by the human eye, that is, light in the visible region. In the following, the wavelength of light in the visible region is 400 nm or more and 800 nm or less.

[Optical device configuration]
With reference to FIG. 1, the configuration of the optical device to be manufactured by the manufacturing method of the first embodiment will be described. As shown in FIG. 1, the optical device 10 includes a base material 11, a first low refractive index region 12, a first lattice region 13, a second low refractive index region 14, a second lattice region 15, and a third low refractive index region. It has a rate region 16. Each of the first low refractive index region 12, the first lattice region 13, the second low refractive index region 14, the second lattice region 15, and the third low refractive index region 16 spreads in a layered manner, and the base material 11 They are arranged in this order from the position closest to. The direction in which the regions are arranged is the first direction, that is, the thickness direction of each region, and the thickness direction of the optical device 10. Further, the side of the third low refractive index region 16 with respect to the base material 11 is the front surface side of the optical device 10, and the side of the base material 11 with respect to the third low refractive index region 16 is the back surface side of the optical device 10. In FIG. 1, the cross-sectional structure of the optical device 10 is shown, and the planar structure of the first lattice region 13 and the planar structure of the second lattice region 15 are shown by partially breaking these regions.

The base material 11 has a plate shape, and among the surfaces of the base material 11, the surface located on the surface side of the optical device 10 is the surface of the base material 11. When the selection target of the optical device 10 is light in the visible region, for example, a synthetic quartz substrate or a film made of a resin such as polyethylene terephthalate or polyethylene naphthalate is used as the base material 11.

The first low refractive index region 12 is in contact with the surface of the base material 11 and extends along the surface of the base material 11. The first lattice region 13 has a plurality of first high refractive index portions 13a and a plurality of first low refractive index portions 13b. Each of the first high refractive index portion 13a and the first low refractive index portion 13b is viewed in one direction when viewed from a direction facing the surface of the base material 11, that is, when viewed from a direction along the first direction. It has a strip shape that extends along a second direction. The first high refractive index portion 13a and the first low refractive index portion 13b are alternately arranged along a third direction orthogonal to the second direction. The second direction and the third direction are directions along the surface of the base material 11, and each of the second direction and the third direction is orthogonal to the first direction. The first lattice region 13 is sandwiched between the first low refractive index region 12 and the second low refractive index region 14 along the first direction, and is in contact with each of these regions.

The second lattice region 15 has a plurality of second high refractive index portions 15a and a plurality of second low refractive index portions 15b. Each of the second high refractive index portion 15a and the second low refractive index portion 15b has a band shape extending along the second direction when viewed from the direction along the first direction, and the second high refractive index portion 15a. The 15a and the second low refractive index portion 15b are alternately arranged along the third direction. That is, the extending direction of the first high refractive index portion 13a and the first low refractive index portion 13b coincides with the extending direction of the second high refractive index portion 15a and the second low refractive index portion 15b, and the first high. The direction in which the refractive index portions 13a and the first low refractive index portion 13b are arranged coincides with the direction in which the second high refractive index portion 15a and the second low refractive index portion 15b are arranged. Then, when viewed from the direction along the first direction, the first high refractive index portion 13a and the second low refractive index portion 15b overlap, and the second high refractive index portion 15a and the first low refractive index portion 13b overlap. ing. The second lattice region 15 is sandwiched between the second low refractive index region 14 and the third low refractive index region 16 along the first direction, and is in contact with each of these regions. In FIG. 1, the planar structure of the first lattice region 13 and the second lattice region 15 is shown by adding dots to the first high refractive index portion 13a and the second high refractive index portion 15a.

The first high refractive index portion 13a and the second high refractive index portion 15a are made of the same material, that is, the refractive index of the first high refractive index portion 13a and the refractive index of the second high refractive index portion 15a. Are equal to each other. The refractive index of the first high refractive index portion 13a and the second high refractive index portion 15a is higher than the refractive index of each of the first low refractive index portion 13b and the second low refractive index portion 15b. Further, the refractive indexes of the first high refractive index portion 13a and the second high refractive index portion 15a are each of the first low refractive index region 12, the second low refractive index region 14, and the third low refractive index region 16. Higher than the refractive index.

Each of the first low refractive index region 12, the second low refractive index region 14, the third low refractive index region 16, the first low refractive index portion 13b, and the second low refractive index portion 15b are made of the same material. That is, all of these indices of refraction are equal. The refractive index of the first low refractive index region 12 is constant regardless of the portion in the region, and the refractive index of the second low refractive index region 14 is also constant regardless of the portion in the region, and is the third low. The refractive index of the refractive index region 16 is also constant regardless of the portion within the region.

The length of the first high refractive index portion 13a in the third direction is the first high element width Dh1, and the length of the first low refractive index portion 13b in the third direction is the first low element width Dl1. The total length of the first high element width Dh1 and the first low element width Dl1 is the period of the arrangement of the first high refractive index portion 13a and the first low refractive index portion 13b in the first lattice region 13. One cycle P1.

The length of the second high refractive index portion 15a in the third direction is the second high element width Dh2, and the length of the second low refractive index portion 15b in the third direction is the second low element width Dl2. The total length of the second high element width Dh2 and the second low element width Dl2 is the period of the arrangement of the second high refractive index portion 15a and the second low refractive index portion 15b in the second lattice region 15. Two cycles P2.

The first high element width Dh1, the first low element width Dl1, the second high element width Dh2, and the second low element width Dl2 are all equal. Then, the first cycle P1 and the second cycle P2 coincide with each other.

The first period P1 and the second period P2 are smaller than the wavelength of light in the visible region, that is, each of the first period P1 and the second period P2 is a sub-wavelength period. In such a configuration, the plurality of first high-refractive index portions 13a in the first lattice region 13 and the plurality of second high-refractive index portions 15a in the second lattice region 15 cause a waveguide mode resonance phenomenon in their respective regions. It constitutes a sub-wavelength grid to generate. The sub-wavelength lattice formed by the first high-refractive index unit 13a and the sub-wavelength lattice formed by the second high-refractive index unit 15a have the same lattice period. That is, the optical device 10 of the present embodiment has a structure in which two sub-wavelength lattices arranged with a gap in the first direction are embedded in a material having a refractive index lower than that of the material constituting these sub-wavelength lattices. ing.

Further, the thickness of the first lattice region 13 is the thickness T1 of the first region, and the thickness of the second lattice region 15 is the thickness T2 of the second region. The first region thickness T1 and the second region thickness T2 are in agreement. The thickness of each of the first low refractive index region 12, the second low refractive index region 14, and the third low refractive index region 16 is not particularly limited.

In the above configuration, the refractive index of the first lattice region 13 is the first high refractive index portion 13a according to the volume ratio of the first high refractive index portion 13a and the first low refractive index portion 13b in the first lattice region 13. It is approximated to the average refractive index obtained by equalizing the refractive index of the above and the refractive index of the first low refractive index portion 13b. Since the volume ratio of the first high refractive index portion 13a and the first low refractive index portion 13b in the first lattice region 13 is 1: 1, the average refractive index of the first lattice region 13 is the first high refractive index portion. It is an average value of the refractive index of 13a and the refractive index of the first low refractive index portion 13b.

Similarly, since the volume ratio of the second high refractive index portion 15a and the second low refractive index portion 15b is 1: 1, the average refractive index of the second lattice region 15 is the refraction of the second high refractive index portion 15a. It is an average value of the rate and the refractive index of the second low refractive index section 15b, and is consistent with the average refractive index of the first lattice region 13. Then, the volume ratio of the first high refractive index portion 13a in the first lattice region 13 is equal to the volume ratio of the second high refractive index portion 15a in the second lattice region 15.

Here, in order to cause the waveguide mode resonance phenomenon in each of the first lattice region 13 and the second lattice region 15, the refractive index of the first lattice region 13 and the first low refraction sandwiching the first lattice region 13 are interposed. The difference between the refractive index of each of the rate region 12 and the second low refractive index region 14 is preferably larger than 0.1. Similarly, the difference between the refractive index of the second lattice region 15 and the refractive index of each of the second low refractive index region 14 and the third low refractive index region 16 sandwiching the second lattice region 15 is 0.1. Is preferably larger than.

Therefore, the refractive index of the high refractive index material constituting the first high refractive index portion 13a and the second high refractive index portion 15a, the first low refractive index region 12, the second low refractive index region 14, and the third low refractive index. The difference between the refractive index of the low refractive index material constituting the region 16, the first low refractive index portion 13b, and the second low refractive index portion 15b is preferably larger than 0.2.

When the selection target of the optical device 10 is light in the visible region, as the low refractive index material, an inorganic substance such as synthetic quartz or a polymer material such as an ultraviolet curable resin, a thermoplastic resin, or a thermocurable resin is used. It can be used, and in this case, as the high refractive index material, TiO ₂ (titanium oxide), Nb ₂ O ₅ (niobium oxide), Ta ₂ O ₅ (tantalum oxide), ZrO (zirconium oxide), ZnS ( Inorganic dielectric materials such as zinc sulfide) can be used.

When the substrate 11 and all of the regions 12 to 16 are composed of a material that transmits the incident light to the optical device 10, the optical device 10 provides wavelength selectivity for both reflected light and transmitted light. Have.

[Action of optical device]
When light is incident on the optical device 10 from the surface side of the optical device 10, the second lattice region 15 has a sub-wavelength lattice, and the second lattice region 15 is lower than the refractive index of the second lattice region 15. Since it is sandwiched between the second low refractive index region 14 and the third low refractive index region 16 having a refractive index, the emission of diffracted light to the surface side is suppressed in the second lattice region 15, and the waveguide mode A resonance phenomenon occurs. That is, light in a specific wavelength region propagates while being multiple-reflected in the second lattice region 15 to cause resonance, and the light in this specific wavelength region is emitted as reflected light to the surface side of the optical device 10. The wavelength region of light that resonates in the second lattice region 15 is determined by the second high element width Dh2, the second period P2, and the second region thickness T2 in the second lattice region 15.

Here, it is unlikely that the light in the specific wavelength region propagating in the second lattice region 15 is multiple-reflected in the second lattice region 15 without loss, and a part of the light in the specific wavelength region is the first. Every reflection within the two grid regions 15 leaks into the second low index region 14. The leaked light passes through the second low refractive index region 14 and enters the first lattice region 13.
Further, light in a wavelength region other than the specific wavelength region passes through the second low refractive index region 14 and enters the first grid region 13 without multiple reflection in the second grid region 15.

When light is incident on the first lattice region 13, the first lattice region 13 has a sub-wavelength lattice, and the first lattice region 13 has a refractive index lower than that of the first lattice region 13. Since it is sandwiched between the low refractive index region 12 and the second low refractive index region 14, the waveguide mode resonance phenomenon also occurs in the first lattice region 13. The wavelength range of light that resonates in the first lattice region 13 is determined by the first high element width Dh1 in the first lattice region 13, the first period P1, and the first region thickness T1. In the first lattice region 13 and the second lattice region 15, the first high element width Dh1 coincides with the second high element width Dh2, the first period P1 coincides with the second period P2, and the first region thickness T1. Consistent with the second region thickness T2. Therefore, the wavelength range of the light that resonates in the first lattice region 13 is the same as the wavelength range of the light that resonates in the second lattice region 15.

Therefore, the light that leaks out in the process of multiple reflection in the second lattice region 15 and enters the first lattice region 13 propagates while being multiple reflected in the first lattice region 13 to cause resonance, and the surface of the optical device 10 It is emitted as reflected light to the side.
Then, the light in the wavelength region that does not cause multiple reflection in the first lattice region 13 passes through the first low refractive index region 12 and the base material 11 and exits to the back surface side of the optical device 10.

As a result, the light in the wavelength region enhanced in the second lattice region 15 and the light in the wavelength region enhanced in the first lattice region 13 are emitted to the surface side of the optical device 10. Since the wavelength ranges of these lights are the same, the intensity of the light in the specific wavelength range emitted from the optical device 10 as reflected light is higher than that of the optical device having only one lattice region, and the light is reflected. The wavelength selectivity of light is enhanced.

Then, among the wavelength ranges included in the light incident on the optical device 10, the light in the wavelength range other than the specific wavelength range emitted as the reflected light is emitted to the back surface side of the optical device 10 as transmitted light. Ru.

When light is incident on the optical device 10 from the back surface side of the optical device 10, the reflected light in the wavelength region enhanced in the second lattice region 15 and the reflected light in the wavelength region enhanced in the first lattice region 13 are reflected. Light is emitted to the back surface side of the optical device 10. Then, among the wavelength ranges included in the incident light, the light in the wavelength range other than the wavelength range emitted as the reflected light is emitted to the surface side of the optical device 10 as transmitted light.

[Manufacturing method of optical device]
The method for manufacturing the above-mentioned optical device 10 will be described with reference to FIGS. 2 to 4.
As shown in FIG. 2, first, a layer made of a low refractive index material is formed on the surface of the base material 11, and a concavo-convex structure is formed on the surface of this layer to form the concavo-convex structure layer 20. The concave-convex structure layer 20 has a flat portion 20a extending along the base material 11 and a plurality of convex portions 20b protruding from the flat portion 20a, and also has a plurality of concave portions 20c which are portions located between the convex portions 20b. .. The plurality of convex portions 20b are arranged at equal intervals in sub-wavelength periods and extend in a band shape in one direction.

The plurality of concave portions 20c are arranged in the same pattern as the plurality of convex portions 20b, and the area of the plurality of convex portions 20b and the area of the plurality of concave portions 20c are equal to each other when viewed from the direction facing the surface of the base material 11. ..

In the convex portion 20b and the concave portion 20c, the period Pt of the arrangement is the desired first period P1 and the second period P2, and the width Dt1 of the convex portion 20b is the desired first. The low element width Dl1 and the second high element width Dh2 are formed, and the width Dt2 of the recess 20c is formed so as to have the desired first high element width Dh1 and the second low element width Dl2. That is, the width Dt1 of the convex portion 20b and the width Dt2 of the concave portion 20c are equal to each other. The height Ht of the convex portion 20b is formed so as to be larger than the desired first region thickness T1.

A known microfabrication technique such as a nanoimprint method or a dry etching method is used to form the uneven structure. Among them, the nanoimprint method is preferable because fine convex portions 20b and concave portions 20c can be easily formed.

For example, when an ultraviolet curable resin is used as a low refractive index material and the concave-convex structure layer 20 is formed by an optical nanoimprint method, first, the surface of the base material 11 is coated with the ultraviolet curable resin. Next, a synthetic quartz mold, which is a concave plate having inverted unevenness of unevenness composed of convex portions 20b and concave portions 20c to be formed, is pressed against the surface of the coating layer made of an ultraviolet curable resin, and the coating layer and the concave plate are pressed. Irradiate with ultraviolet rays. Subsequently, the intaglio is released from the cured ultraviolet curable resin. As a result, the unevenness of the intaglio is transferred to the ultraviolet curable resin to form the convex portion 20b and the concave portion 20c, and the convex portion 20b and the concave portion 20c and the base material 11 are made of an ultraviolet curable resin. A flat portion 20a is formed as a residual film.

Next, as shown in FIG. 3, a high refractive index layer 21 made of a high refractive index material is formed on the surface of the concave-convex structure layer 20. As a method for forming the high refractive index layer 21, a known film forming technique such as a vacuum vapor deposition method is used. The high refractive index layer 21 is formed on the convex portion 20b and the concave portion 20c. That is, the high refractive index layer 21 includes a first layered portion 21a located on the concave portion 20c and a second layered portion 21b located on the convex portion 20b.

Since the width Dt1 of the convex portion 20b and the width Dt2 of the concave portion 20c in the concave-convex structure layer 20 are equal to each other, the width Ds1 of the first layered portion 21a and the width Ds2 of the second layered portion 21b are equal. Further, the period of the arrangement of the first layered portion 21a and the period of the arrangement of the second layered portion 21b are the period Pt, which are equal to each other. The thickness of the high refractive index layer 21 is, that is, the thickness Ts1 of the first layered portion 21a and the thickness Ts2 of the second layered portion, and these thicknesses are equal. The thickness of the high refractive index layer 21 is smaller than the height Ht of the convex portion 20b, and is formed so as to have a desired first region thickness T1 and second region thickness T2. That is, the first layered portion 21a and the second layered portion 21b form a sub-wavelength lattice having the same pattern as each other.

Next, as shown in FIG. 4, it is a layer made of the same low refractive index material as the material for forming the uneven structure layer 20 so as to cover the surface of the structure composed of the uneven structure layer 20 and the high refractive index layer 21. The embedded layer 22 is formed to fill the unevenness of the structure up to the second layer-shaped portion 21b. The embedded layer 22 includes a flat portion 22a, a plurality of convex portions 22b, and a concave portion 22c located between the convex portions 22b. The convex portion 22b fills the space between the convex portions 20b and the second layer-shaped portion 21b on the first layer-shaped portion 21a. The flat portion 22a is located on the second layered portion 21b and extends in the direction along the surface of the base material 11. The flat portion 22a and the convex portion 22b are connected so that the convex portion 22b protrudes from the flat portion 22a toward the base material 11.

The period of the convex portion 22b coincides with the period Pt of the convex portion 20b in the concave-convex structure layer 20, the width of the convex portion 22b coincides with the width Dt2 of the concave portion 20c, and the width of the concave portion 22c corresponds to the width Dt1 of the convex portion 20b. Matches with. The height of the convex portion 20b is larger than the thickness of the high refractive index layer 21.

As a method for forming the embedded layer 22, known film forming techniques such as various coating methods are used. For example, when an ultraviolet curable resin is used as the low refractive index material, first, the surface of the structure is coated with the ultraviolet curable resin. Next, a flat plate having releasability is pressed against the surface of the coating layer made of an ultraviolet curable resin, and the coating layer is irradiated with ultraviolet rays. Subsequently, the flat plate is released from the cured ultraviolet curable resin. Therefore, when an ultraviolet curable resin is used, the planographic plate must be made of a material that transmits ultraviolet rays.

As a result, the optical device 10 is formed. The flat portion 20a of the concave-convex structure layer 20 is the first low refractive index region 12. The first lattice region 13 is composed of the first layered portion 21a of the high refractive index layer 21 and the portion of the convex portion 20b of the concave-convex structure layer 20 adjacent to the first layered portion 21a, and the first layered portion 21a is formed. The first high refractive index portion 13a, and the portion of the convex portion 20b adjacent to the first layered portion 21a is the first low refractive index portion 13b. A second portion of the convex portion 20b of the concave-convex structure layer 20 that extends beyond the first layered portion 21a and a portion of the convex portion 22b of the embedded layer 22 that is adjacent to the convex portion 20b of the concave-convex structure layer 20. The low refractive index region 14 is configured.

The second lattice region 15 is composed of the second layered portion 21b of the high refractive index layer 21 and the portion of the convex portion 22b of the embedded layer 22 adjacent to the second layered portion 21b, and the second layered portion 21b is the second layer. 2 The high refractive index portion 15a, and the portion of the convex portion 22b adjacent to the second layered portion 21b is the second low refractive index portion 15b. The flat portion 22a of the embedded layer 22 is the third low refractive index region 16.

In the optical device 10 manufactured by such a manufacturing method, the first low refractive index region 12 and the first low refractive index portion 13b of the first lattice region 13 are continuous, and the first low refractive index portion 13b and the first 2 In the low refractive index region 14, the portion adjacent to the first low refractive index portion 13b is continuous, the first low refractive index region 12, the first low refractive index portion 13b, and the second low refractive index region 14 Among them, the portion adjacent to the first low refractive index portion 13b is one structure. Further, in the second low refractive index region 14, the portion of the second lattice region 15 adjacent to the second low refractive index portion 15b and the second low refractive index portion 15b are continuous, and the second low refractive index portion 15b And the third low refractive index region 16 are continuous, a portion of the second low refractive index region 14 adjacent to the second low refractive index portion 15b, a second low refractive index portion 15b, and a third low refractive index. The region 16 is one structure.

As described above, in the optical device 10, the reflected light obtained by emitting the light in the wavelength region enhanced in the first lattice region 13 and the light in the wavelength region enhanced in the second lattice region 15. Increases the strength of. Therefore, it is not necessary to precisely control the film thickness of the layer in contact with the first lattice region 13 and the second lattice region 15, and specifically, when the optical device 10 is formed by using the nanoimprint method, it remains. It is possible to manufacture the optical device 10 with improved wavelength selectivity without requiring precise control of the film thickness. Therefore, the optical device 10 can be easily manufactured.

Further, since the optical device 10 can be formed by a manufacturing method that combines an optical nanoimprint method and a vacuum vapor deposition method, it is suitable for manufacturing by a roll-to-roll method. Therefore, the configuration of the optical device 10 is also suitable for mass production.

When the high refractive index layer 21 is formed by using the vacuum vapor deposition method, the high refractive index material may also adhere to the side surface of the convex portion 20b of the concave-convex structure layer 20. As a result, as shown in FIG. 5, in the optical device 10, the second low refractive index region 14 is adjacent to the first high refractive index portion 13a and the second high refractive index when viewed from the direction along the first direction. A third high refractive index portion 17 extending in the thickness direction of the second low refractive index region 14 is included so as to connect the ends thereof with the rate portion 15a. The third high refractive index section 17 does not have to completely connect the first high refractive index section 13a and the second high refractive index section 15a, and the third high refractive index section 17 and the first high refractive index section 17 do not have to be completely connected. The rate section 13a and the second high refractive index section 15a may be separated from each other.

Even when the third high refractive index portion 17 is present, the volume ratio of the third high refractive index portion 17 in the second low refractive index region 14 is very small, and in the second low refractive index region 14, The part composed of low refractive index material is dominant. Therefore, the refractive index of the second low refractive index region 14 is slightly larger than the refractive index of each of the first low refractive index region 12 and the third low refractive index region 16, but the first lattice region 13 and the second It is sufficiently smaller than each refractive index of the lattice region 15. Therefore, a structure suitable for the waveguide mode resonance phenomenon is realized in which each of the first lattice region 13 and the second lattice region 15 is sandwiched between regions having a lower refractive index than these regions.

[Modification example of optical device]
In the above-mentioned production method, the concave-convex structure layer 20 may be formed by the nanoimprint method using a thermosetting resin or a thermoplastic resin instead of the ultraviolet curable resin. When a thermosetting resin is used, the irradiation of ultraviolet rays may be changed to heating, and when a thermoplastic resin is used, the irradiation of ultraviolet rays may be changed to heating and cooling.

However, when the concave-convex structure layer 20 is formed by using the thermoplastic resin, a material different from the thermoplastic resin is used in order to prevent the concave-convex structure layer 20 from being heated and deformed when the embedded layer 22 is formed. It is preferable to form the embedded layer 22.

For example, as shown in FIG. 6, the concave-convex structure layer 20 may be formed of a thermoplastic resin, and the embedded layer 22 may be formed of an ultraviolet curable resin. In this case, the refractive index of the low refractive index material constituting the concave-convex structure layer 20 and the refractive index of the low refractive index material constituting the embedded layer 22 may be different from each other, and the refractive index of each low refractive index material may be different from each other. The index may be lower than the refractive index of the high refractive index material constituting the high refractive index layer 21.

When the refractive index of the low refractive index material constituting the concave-convex structure layer 20 and the refractive index of the low refractive index material constituting the embedded layer 22 are different from each other, in the manufactured optical device 10, the first low refractive index region The refractive indexes of 12, the second low refractive index region 14, and the third low refractive index region 16 are different from each other. Further, the second low refractive index region 14 has a structure in which strip-shaped portions made of materials having different refractive indexes extend along the second direction and are alternately arranged along the third direction.

Not only when the concave-convex structure layer 20 is formed of a thermoplastic resin and the embedded layer 22 is formed of a material different from the thermoplastic resin, the refractive index of the low-refractive index material constituting the concave-convex structure layer 20 and the embedding The refractive indexes of the low refractive index materials constituting the layer 22 may be different from each other. In short, the refractive index of the low refractive index material constituting each of the concave-convex structure layer 20 and the embedded layer 22 may be lower than the refractive index of the high refractive index material constituting the high refractive index layer 21. Then, in the manufactured optical device 10, the first low refractive index region 12, the second low refractive index region 14, and the third are higher than the refractive indexes of the first lattice region 13 and the second lattice region 15, respectively. It is sufficient that each of the refractive indexes of the low refractive index region 16 is low.

Further, as shown in FIG. 7, the base material 11 and the concave-convex structure layer 20 may be one continuous structure. That is, the uneven structure layer 20 is formed by forming the uneven structure on the surface of the base material 11 made of the low refractive index material. For example, a sheet made of a thermoplastic resin may be used as the base material 11 to form an uneven structure on the surface of the base material 11, or a substrate made of synthetic quartz may be used as the base material 11 to form a surface of the base material 11. An uneven structure may be formed on the surface. A known technique such as a dry etching method may be used for forming the uneven structure on the synthetic quartz substrate. In this case, in the manufactured optical device 10, the base material 11 and the first low refractive index region 12 are continuous with each other.

[Application example of optical device]
A specific application example of the above-mentioned optical device 10 will be described.
<Wavelength selection filter>
The first application example of the optical device 10 is a form in which the optical device 10 is used as a wavelength selection filter. As shown in FIG. 8, when the wavelength selection filter 50 receives incident light I1 containing light having a plurality of wavelengths, it reflects light I2 in a specific wavelength range and excludes light in this specific wavelength range. Light I3 is transmitted. The configuration of the optical device 10 is applied to the wavelength selection filter 50, and for example, the wavelength selection filter 50 is arranged so that light is incident from the surface side of the optical device 10. As described above, the wavelength regions of the light I2 and the light I3 can be adjusted by setting the period of the sub-wavelength grid included in the first grid region 13 and the second grid region 15.

The wavelength selection filter 50 may be used in a form using light I2 which is reflected light, may be used in a form using light I3 which is transmitted light, or both light I2 and light I3. It may be used in the form of utilizing. For example, the wavelength selection filter 50 is used as a device that requires color separation, a member that constitutes lighting, and the like.

As described above, since the wavelength selectivity is enhanced according to the optical device 10 of the first embodiment, the wavelength selection filter 50 with enhanced wavelength selectivity can be realized by applying the configuration of the optical device 10. ..

<Display body>
A second application example of the optical device 10 is a form in which the optical device 10 is used as a display body. The display body may be used for the purpose of increasing the difficulty of forgery of the article, may be used for the purpose of enhancing the design of the article, or may be used for these purposes in combination. For the purpose of increasing the difficulty of counterfeiting goods, the display body is, for example, authentication documents such as passports and driver's licenses, securities such as gift certificates and checks, cards such as credit cards and cash cards, banknotes, etc. It will be pasted. In addition, for the purpose of enhancing the design of the article, the display body is, for example, a decorative object to be worn, an article carried by a user, an article to be stationary such as furniture or a home appliance, a wall, a door, or the like. It can be attached to structures, etc.

As shown in FIG. 9, the display body 60 has a front surface 60F and a back surface 60R which is a surface opposite to the front surface 60F, and the display body 60 is a first surface when viewed from a direction facing the front surface 60F. The display area 61A, the second display area 61B, and the third display area 61C are included. The first display area 61A is an area in which a plurality of first pixels 62A are arranged, the second display area 61B is an area in which a plurality of second pixels 62B are arranged, and the third display area 61C is an area in which a plurality of second pixels 62B are arranged. , This is an area in which a plurality of third pixels 62C are arranged. In other words, the first display area 61A is composed of a set of a plurality of first pixels 62A, and the second display area 61B is composed of a set of a plurality of second pixels 62B, and is a third display area. The 61C is composed of a set of a plurality of third pixels 62C.

Each of the first display area 61A, the second display area 61B, and the third display area 61C may be a character, a symbol, a figure, a pattern, a pattern, or a combination of these areas alone or two or more of these areas. Express the background of. As an example, in the configuration shown in FIG. 9, a circular figure is represented by the first display area 61A, a triangular figure is represented by the second display area 61B, and a background is represented by the third display area 61C.

The configuration of the optical device 10 is applied to each of the first pixel 62A, the second pixel 62B, and the third pixel 62C. Each of the first pixel 62A, the second pixel 62B, and the third pixel 62C has the second direction and the third direction oriented along the surface 60F of the display body 60, that is, the display body 60. The sub-wavelength grids are arranged so as to line up along the surface 60F of the surface. For example, these pixels 62A, 62B, and 62C are arranged so that the front surface side of the optical device 10 is the front surface side of the display body 60.

In the first pixel 62A, the second pixel 62B, and the third pixel 62C, the first cycle P1 of the first lattice region 13, that is, the second cycle P2 of the second grid region 15 has a different cycle for each pixel. is there. Therefore, in the first pixel 62A, the second pixel 62B, and the third pixel 62C, the wavelength ranges in which resonance due to the waveguide mode resonance phenomenon occurs in the first lattice region 13 and the second lattice region 15 are different from each other.

As a result, when incident light containing light of a plurality of wavelengths is received, the wavelength range of the reflected light emitted from the first pixel 62A, the wavelength range of the reflected light emitted from the second pixel 62B, and the third pixel. The wavelength range of the light emitted from 62C is different from each other. Further, when the incident light is received, the wavelength range of the transmitted light emitted from the first pixel 62A, the wavelength range of the transmitted light emitted from the second pixel 62B, and the transmitted light emitted from the third pixel 62C. Wavelength range is different from each other.

That is, as shown in FIG. 10, when the incident light I1 is irradiated from the outside of the display body 60 toward the surface 60F of the display body 60, the surface side of the display body 60 is reflected light from the first pixel 62A. I4 is emitted, reflected light I5 is emitted from the second pixel 62B, and reflected light I6 is emitted from the third pixel 62C. Therefore, when the surface 60F of the display body 60 is viewed from the surface side, the hue color corresponding to the wavelength range of the reflected light I4 is visually recognized in the first display area 61A, and the wavelength of the reflected light I5 is recognized in the second display area 61B. The hue color corresponding to the region is visually recognized, and the hue color corresponding to the wavelength region of the reflected light I6 is visually recognized in the third display region 61C. Since the wavelength range of the reflected light I4, the wavelength range of the reflected light I5, and the wavelength range of the reflected light I6 are different from each other, the first display area 61A, the second display area 61B, and the third display area 61C have different hues. Looks like the color of.

Therefore, according to the surface reflection observation in which the surface 60F is observed from the surface side of the display body 60 in a state where the incident light I1 is irradiated from the outside of the display body 60 toward the surface 60F, the first display of different colors is observed. An image composed of the area 61A, the second display area 61B, and the third display area 61C is visually recognized.

Further, when the incident light I1 is irradiated from the outside of the display body 60 toward the surface 60F of the display body 60, the transmitted light I7 is emitted from the first pixel 62A to the back surface side of the display body 60, and the second The transmitted light I8 is emitted from the pixel 62B, and the transmitted light I9 is emitted from the third pixel 62C. Therefore, when the back surface 60R of the display body 60 is viewed from the back surface side, the hue color corresponding to the wavelength range of the transmitted light I7 is visually recognized in the first display area 61A, and the wavelength of the transmitted light I8 is displayed in the second display area 61B. The hue color corresponding to the region is visually recognized, and the hue color corresponding to the wavelength region of the transmitted light I9 is visually recognized in the third display region 61C. Since the wavelength range of the transmitted light I7, the wavelength range of the transmitted light I8, and the wavelength range of the transmitted light I9 are different from each other, the first display area 61A, the second display area 61B, and the third display area 61C have different hues. Looks like the color of.

Therefore, even in the backside transmission observation in which the back surface 60R is observed from the back surface side of the display body 60 in a state where the incident light I1 is irradiated from the outside of the display body 60 toward the front surface 60F, the first display regions having different colors are also observed. An image composed of 61A, a second display area 61B, and a third display area 61C is visually recognized.

Further, since the wavelength range of the reflected light I4 and the wavelength range of the transmitted light I7 are different, the first display area 61A is obtained when the display body 60 is viewed from the front surface side and when the display body 60 is viewed from the back surface side. The hue of the color visually recognized is different. The color seen from the back surface side is a color corresponding to the complementary color of the color seen from the front surface side. Similarly, when the display body 60 is viewed from the front surface side and when the display body 60 is viewed from the back surface side, the hue of the color visually recognized in the second display area 61B is different, and the display body 60 is visually recognized in the third display area 61C. The hue of the color to be produced is also different.

Therefore, in the front surface reflection observation and the back surface transmission observation, images of different colors are visually recognized on the display body 60. Therefore, in the article provided with the display body 60, the difficulty of counterfeiting and the designability are further enhanced. In addition, it is easy to identify the front and back sides of the display body 60.

Then, as described above, since the wavelength selectivity is enhanced according to the optical device 10 of the first embodiment, the configuration of the optical device 10 is applied to the pixels 62A, 62B, 62C, so that each display area 61A , 61B, 61C enhances the vividness and brightness of the colors visually recognized. Therefore, the visibility of the image formed by the display body 60 is enhanced. Further, in the optical device 10 of the first embodiment, since a flexible base material 11 such as a resin film can be used, it is possible to realize a display body 60 having a high degree of freedom in shape deformation. Is.

Between the first pixel 62A, the second pixel 62B, and the third pixel 62C, the base material 11, the first low refractive index region 12, the first lattice region 13, the second low refractive index region 14, and the second lattice region 15 , And each of the third low refractive index region 16 is continuous. That is, the first pixel 62A, the second pixel 62B, and the third pixel 62C have a common base material 11, a concavo-convex structure layer 20 that is mutually continuous between these pixels, and each other between these pixels. It has a continuous embedded layer 22.

The concavo-convex structure layer 20 in each of the first pixel 62A, the second pixel 62B, and the third pixel 62C uses, for example, the nanoimprint method to change the concavo-convex cycle at the portion corresponding to each pixel 62A, 62B, 62C. It can be formed at the same time by using a synthetic quartz mold. Further, the high refractive index layer 21 and the embedded layer 22 can also form the portions corresponding to the pixels 62A, 62B, 62C at the same time. Therefore, the pixels 62A, 62B, and 62C that exhibit different colors can be easily formed.

Further, the number of display areas included in the display body 60, that is, the number of display areas to which the pixels to which the configuration of the optical device 10 is applied are arranged and exhibit colors of different hues are not particularly limited, and the number of display areas is not particularly limited. May be one, or may be four or more. Further, the display body 60 has a region having a configuration different from that of the optical device 10, for example, a region having a structure in which only a flat layer made of a low refractive index material is laminated on the base material 11. May be good.

Further, the display area may include a display element to which the configuration of the optical device 10 is applied, and the display element is not limited to a pixel which is a minimum unit of repetition for forming a raster image, and forms a vector image. It may be an area connecting anchors for the purpose.

<Color filter>
A third application example of the optical device 10 is a form in which the optical device 10 is used as a color filter.
As shown in FIG. 11, the color filter 70 includes a plurality of pixels 71 arranged in a matrix, and each pixel 71 has three sub-pixels 71R for red, sub-pixels 71G for green, and sub-pixels 71B for blue. It is composed of two sub-pixels.

The color filter 70 is a reflective color filter and is provided in the display device. The side of the color filter 70 where the observer looking at the display surface of the display device is located is the front side of the color filter 70, and the side opposite to the front side of the color filter 70 is the back side of the color filter 70. Is. The color filter 70 is irradiated with light from the surface side. The intensity of the light applied to the color filter 70 can be changed for each sub-pixel by a liquid crystal device or the like.

The red sub-pixel 71R converts the light incident on the red sub-pixel 71R into red light and reflects the light. The green sub-pixel 71G converts the light incident on the green sub-pixel 71G into green light and reflects it. The blue sub-pixel 71B converts the light incident on the blue sub-pixel 71B into blue light and reflects it.

The configuration of the optical device 10 is applied to each of the red sub-pixel 71R, the green sub-pixel 71G, and the blue sub-pixel 71B. The red sub-pixel 71R, the green sub-pixel 71G, and the blue sub-pixel 71B are displayed so that the second direction and the third direction are along the surface of the color filter 70, that is, they are displayed. The sub-wavelength lattices are arranged so as to line up along the display surface of the device. For example, these sub-pixels 71R, 71G, and 71B are arranged so that the surface side of the optical device 10 is the surface side of the color filter 70.

As shown in FIG. 12, when the red sub-pixel 71R receives the incident light I1 containing light of a plurality of wavelengths from the surface side of the color filter 70, the red reflected light Ir is emitted to the surface side. The first period P1 of the first lattice region 13 and the second period P2 of the second lattice region 15 are set. When the green sub-pixel 71G receives the incident light I1, the first period P1 and the second period P2 are set so as to emit the green reflected light Ig toward the surface side. When the blue sub-pixel 71B receives the incident light I1, the first period P1 and the second period P2 are set so as to emit the blue reflected light Ib to the surface side. By changing the intensity of the incident light for each of the sub-pixels 71R, 71G, and 71B, the color visually recognized as the pixel 71 is changed, and the image displayed by the display device is formed by the set of the pixels 71.

As described above, since the wavelength selectivity is enhanced according to the optical device 10 of the first embodiment, the configuration of the optical device 10 is applied to the sub-pixels 71R, 71G, 71B, so that the sub-pixels 71R, The sharpness and brightness of colors in 71G and 71B are enhanced.

Further, similarly to the form of the display body 60 described above, between the red sub-pixel 71R, the green sub-pixel 71G, and the blue sub-pixel 71B, the base material 11, the first low refractive index region 12, and the first lattice Each of the region 13, the second low refractive index region 14, the second lattice region 15, and the third low refractive index region 16 is continuous. That is, the red sub-pixel 71R, the green sub-pixel 71G, and the blue sub-pixel 71B have a common base material 11, a concavo-convex structure layer 20 that is continuous between these sub-pixels, and their sub-pixels. It has an embedded layer 22 that is continuous with each other between pixels.

The concavo-convex structure layer 20 in each of the red sub-pixel 71R, the green sub-pixel 71G, and the blue sub-pixel 71B has irregularities in the portions corresponding to the sub-pixels 71R, 71G, and 71B, for example, by using the nanoimprint method. By using synthetic quartz molds with different cycles, they can be formed at the same time. Further, the high refractive index layer 21 and the embedded layer 22 can also simultaneously form portions corresponding to the sub-pixels 71R, 71G, and 71B. Therefore, the color filter 70 having the sub-pixels 71R, 71G, and 71B of three kinds of colors can be easily formed.

As described above, according to the first embodiment, the effects listed below can be obtained.
(1) When light is incident on the lattice regions 13 and 15, a waveguide mode resonance phenomenon occurs in the lattice regions 13 and 15. Then, the wavelength region of the light that resonates in the first lattice region 13 and the wavelength region of the light that resonates in the second lattice region 15 coincide with each other. Therefore, since the light in the wavelength region enhanced in each of the two lattice regions 13 and 15 is obtained as the reflected light, the intensity of the light emitted as the reflected light is compared with the optical device having only one lattice region. Becomes larger. That is, the wavelength selectivity is enhanced without requiring precise control of the film thickness of the layer in contact with the lattice region.

(2) It comprises a step of forming a concavo-convex structure layer 20 made of a low refractive index material, a step of forming a high refractive index layer 21 on the surface of the concavo-convex structure layer 20, and a step of forming the concavo-convex structure layer 20 and a high refractive index layer 21. The optical device 10 is formed by a step of forming an embedded layer made of a low refractive index material on the surface of the structure. Therefore, since the wavelength selectivity of the optical device 10 is enhanced without requiring precise control of the film thickness of the layer in contact with the sub-wavelength lattice, the optical device 10 with enhanced wavelength selectivity can be easily manufactured. it can.

(3) In particular, in a manufacturing method in which a resin is used as a low refractive index material and a concave plate is pressed against a coating layer made of the resin to form the concave-convex structure layer 20 by curing the resin, the concave-convex structure layer 20 is formed by using the nanoimprint method. Therefore, the concavo-convex structure layer 20 having fine concavities and convexities can be preferably and easily formed.

(4) The first low refractive index region 12, the first low refractive index portion 13b, and the portion of the second low refractive index region 14 adjacent to the first low refractive index portion 13b are mutually continuous 1 There are two structures, the third low refractive index region 16, the second low refractive index portion 15b, and the portion of the second low refractive index region 14 adjacent to the second low refractive index portion 15b are mutually connected. In the configuration of one continuous structure, each of the portions of the structure can be manufactured in one step by using the above-mentioned manufacturing method, so that the optical device 10 can be easily manufactured. Is.

(5) In a configuration in which the difference in refractive index between each of the above structures and the first high refractive index portion 13a and the second high refractive index portion 15a is larger than 0.2, the waveguide mode is set in the lattice regions 13 and 15 respectively. The resonance phenomenon is likely to occur favorably, and the intensity of the reflected light from each of the lattice regions 13 and 15 is further enhanced. Therefore, the wavelength selectivity in the optical device 10 is further enhanced.

(6) The low refractive index material constituting each of the above structures is any of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin, and the first high refractive index portion 13a and the second high refractive index When the material constituting the portion 15a contains an inorganic compound, the waveguide mode resonance phenomenon is likely to occur favorably in the lattice regions 13 and 15, and the intensity of the reflected light from the lattice regions 13 and 15 is further increased. Be done. Therefore, the wavelength selectivity in the optical device 10 is further enhanced. Further, it is possible to reduce the material cost required for manufacturing the optical device 10 and to apply a simple manufacturing method such as a nanoimprint method.

(7) The second low refractive index region 14 is located between the ends of the first high refractive index portion 13a and the second high refractive index portion 15a, which are adjacent to each other when viewed from the direction along the first direction. In the configuration including the third high refractive index portion 17 extending along the thickness direction of the refractive index region 14, the high refractive index portions 13a and 15a can be formed by using the vacuum vapor deposition method, which is suitable for the sub-wavelength lattice. It can be formed. Even in this case, the configuration of the second low refractive index region 14 for causing the waveguide mode resonance phenomenon is preferably realized.

(Second Embodiment)
A method for manufacturing an optical device and a second embodiment of the optical device manufactured by this manufacturing method will be described with reference to FIGS. 13 to 16. Hereinafter, the differences between the second embodiment and the first embodiment will be mainly described, and the same reference numerals will be given to the same configurations as those of the first embodiment, and the description thereof will be omitted.

[Optical device configuration]
The configuration of the optical device to be manufactured by the manufacturing method of the second embodiment will be described with reference to FIGS. 13 and 14. As shown in FIG. 13, the optical device 30 of the second embodiment has the first low refractive index region 12, the first lattice region 13, the second low refractive index region 14, and the second lattice described in the first embodiment. It includes two resonance structure portions 18, which are structures including a region 15 and a third low refractive index region 16.

The first resonance structure portion 18A and the second resonance structure portion 18B, which are the two resonance structure portions 18, are adjacent to each other in the first direction, and the two resonance structure portions 18A and 18B are sandwiched between the two base materials 11. It has been. In other words, the optical device 30 of the second embodiment has a structure in which two optical devices 10 having the configuration of the first embodiment are joined so that the third low refractive index regions 16 face each other. That is, the optical device 30 of the second embodiment has four sub-wavelength lattices arranged with a gap in the first direction, and these sub-wavelength lattices have a structure embedded in a low refractive index material. .. The side of the other base material 11 with respect to one base material 11 is the front surface side of the optical device 30, and the side of the other base material 11 with respect to the other base material 11 is the back surface side of the optical device 30.

In the two resonance structure portions 18A and 18B, the extending directions of the high refractive index portions 13a and 15a are the same. That is, all the first high refractive index portions 13a and the second high refractive index portion 15a included in the optical device 30 extend along the second direction, and all the first low refractive index portions 13b and the first low refractive index portion 13b included in the optical device 30. 2 The low refractive index portion 15b also extends along the second direction. Then, in each of the four lattice regions 13 and 15 of the optical device 30, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b are alternately arranged along the third direction. That is, the arrangement directions of the sub-wavelength grids are the same for the four sub-wavelength grids of the optical device 30.

The first high refractive index portion 13a of the first resonance structure portion 18A may overlap with the first high refractive index portion 13a of the second resonance structure portion 18B when viewed from the direction along the first direction. It may overlap with the second high refractive index portion 15a of the second resonance structure portion 18B, or may overlap with a part of the first high refractive index portion 13a and a part of the second high refractive index portion 15a of the second resonance structure portion 18B. It may overlap.

The first resonance structure portion 18A and the second resonance structure portion 18B may share a low refractive index region at their boundary portions. For example, in the example shown in FIG. 13, the third low refractive index region 16 included in the first resonance structure portion 18A and the third low refractive index region 16 included in the second resonance structure portion 18B are continuous, and these There are no region boundaries.

Within one resonance structure portion 18, the first period P1 of the first lattice region 13 and the second period P2 of the second lattice region 15 are the same, and this period is the structural period Pk of the resonance structure portion 18. ..

The structural period Pk of the first resonance structure portion 18A and the structural period Pk of the second resonance structure portion 18B may be the same as shown in FIG. 13, or may be different from each other as shown in FIG. Good.

In the form in which the two resonance structure portions 18A and 18B have the same structural period Pk, the patterns of the four sub-wavelength lattices included in the optical device 30 are all the same, and the high element widths Dh1 and 18B in the resonance structure portions 18A and 18B. Dh2 are all equal, and region thicknesses T1 and T2 are all equal. Further, in the form in which the two resonance structure portions 18A and 18B have different structural periods Pk, the pattern of the four sub-wavelength lattices included in the optical device 30 is different for each resonance structure portion 18A and 18B. That is, the high element widths Dh1 and Dh2 are different for each of the resonance structure portions 18A and 18B. The region thicknesses T1 and T2 may all be the same, or may be different for each of the resonance structure portions 18A and 18B.

[Action of optical device]
In the configuration in which the two resonance structure portions 18A and 18B have the same structural period Pk, the wavelength regions of the light causing resonance are the same in all of the four lattice regions 13 and 15 of the optical device 30. Therefore, when light is incident on the optical device 30 from the surface side of the optical device 30, among the light in a specific wavelength range that is multiple-reflected in the upper lattice region, the light leaked from this grid region in the process of multiple reflection. Enters the underlying lattice region and undergoes multiple reflections, and this phenomenon is repeated for the number of lattice regions. As a result, the reflected light in a specific wavelength region enhanced in each of the four lattice regions 13 and 15 is emitted to the surface side of the optical device 30. Therefore, as compared with the optical device 10 of the first embodiment, the intensity of the light in the specific wavelength range emitted from the optical device 30 as the reflected light is higher, and the wavelength selectivity of the reflected light is further enhanced.

On the other hand, in the configuration in which the two resonance structure portions 18A and 18B have different structural periods Pk, the wavelength range of light that causes resonance in the lattice regions 13 and 15 of the first resonance structure portion 18A and the second resonance structure portion The wavelength regions of light that resonate in the lattice regions 13 and 15 of 18B are different from each other. Therefore, when light is incident on the optical device 30 from the surface side of the optical device 30, the wavelengths in which the light in a specific wavelength range is multiple-reflected in the lattice regions 13 and 15 of the resonance structure portion 18 in the upper layer and are not multiple-reflected. Light in the region passes through the resonance structure portion 18 and enters the resonance structure portion 18 in the lower layer, and light in a wavelength region different from that in the resonance structure portion 18 in the upper layer is emitted from each lattice region 13 of the resonance structure portion 18 in the lower layer. Multiple reflections at, and 15. As a result, on the surface side of the optical device 30, the light in the first wavelength region enhanced by the lattice regions 13 and 15 of the first resonance structure portion 18A and the lattice region 13 of the second resonance structure portion 18B , 15 The reflected light including the light in the second wavelength region enhanced at 15 is emitted.

Then, on the back surface side of the optical device 30, a wavelength range excluding the first wavelength range and the second wavelength range emitted as the reflected light in the wavelength range included in the incident light on the optical device 30. Light is emitted as transmitted light. According to such a configuration, in the optical device 30, it is possible to expand the wavelength range included in the reflected light and narrow the wavelength range included in the transmitted light while increasing the intensity of the reflected light. Therefore, the degree of freedom in adjusting the hue observed as reflected light or transmitted light can be increased by setting the structural period Pk in the resonance structure portions 18A and 18B.

[Application example of optical device]
The configuration of the optical device 30 of the second embodiment may be applied to the wavelength selection filter 50 or may be applied to the display element included in the display body 60, as in the application example shown in the first embodiment. However, it may be applied to the sub-pixels included in the color filter 70.

For example, when a configuration in which the two resonance structure portions 18A and 18B have the same structural period Pk is applied, the wavelength selectivity of the reflected light is further enhanced in the wavelength selection filter 50. Further, in the display body 60, the visibility of the image is enhanced by increasing the sharpness and brightness of the colors visually recognized in the display areas 61A, 61B, and 61C by surface reflection observation. Further, in the color filter 70, the color sharpness and brightness of the sub-pixels 71R, 71G, 71B are enhanced, and the reflection type color including the sub-pixels 71R, 71B, 71G that emit the reflected light having high monochromaticity. The filter 70 is realized.

Further, for example, when a configuration in which the two resonance structure portions 18A and 18B have different structural periods Pk is applied, the degree of freedom in adjusting the hue observed as reflected light or transmitted light is increased in the wavelength selection filter 50. Be done. Further, in the display body 60, the degree of freedom in adjusting the hue of the image visually recognized in the front surface reflection observation and the back surface transmission observation is increased. Further, as the color filter 70, a transmission type color filter, that is, the color filter is irradiated with light from the back surface side of the color filter, and the observer sees the transmitted light transmitted through the color filter from the front surface side of the color filter. It is possible to realize a color filter used in the form.

Specifically, in the green sub-pixel 71G, the light in the red wavelength region is strengthened by the first resonance structure portion 18A and emitted as reflected light to the back surface side, and the blue wavelength is emitted by the second resonance structure portion 18B. It is configured so that the light in the region is strengthened and emitted as reflected light to the back surface side. According to such a configuration, when white incident light is received from the back surface side of the color filter 70, green transmitted light is emitted to the front surface side of the color filter 70, so that it is viewed from the front surface side of the color filter 70. , Green is visually recognized on the green sub-pixel 71G. Similarly, by adjusting the structural period Pk in the resonance structure portions 18A and 18B, the red sub-pixel 71R emits transmitted light in the red wavelength region, and the blue sub-pixel 71B emits transmitted light in the blue wavelength region. It is configured as follows. As a result, a transmissive color filter 70 having sub-pixels 71R, 71B, and 71G that emit transmitted light having high monochromaticity is realized.

[Manufacturing method of optical device]
The manufacturing method of the optical device 30 of the second embodiment will be described with reference to FIGS. 15 and 16. First, in the production of the optical device 30 of the second embodiment, the uneven structure layer 20 and the high refractive index layer 21 are sequentially formed on the base material 11 as in the first embodiment.

Subsequently, as shown in FIG. 15, the two concave-convex structures 31, which are structures composed of the base material 11, the concave-convex structure layer 20, and the high-refractive index layer 21, face each other so that the high-refractive index layers 21 face each other. Then, as shown in FIG. 16, the concavo-convex structure 31 is joined by filling the region between the two concavo-convex structures 31 with a low refractive index material. As a result, the optical device 30 is formed.

As shown in FIG. 16, the portion formed between the two concave-convex structures 31 by embedding with a low refractive index material is the embedding layer 22. Similar to the first embodiment, if the low refractive index material constituting the embedded layer 22 is a material having a lower refractive index than the high refractive index material constituting the high refractive index layer 21, the concave-convex structure layer 20 is formed. It may be a material different from the material. Further, in the two concave-convex structures 31, the low-refractive index material forming the concave-convex structure layer 20 and the high-refractive index material forming the high refractive index layer 21 may be different from each other.

In a state where the two concave-convex structures 31 face each other, the first layered portions 21a may face each other, or the first layered portion 21a in one concave-convex structure 31 and the second concave-convex structure 31 in the other concave-convex structure 31. The two-layered portion 21b may face each other. Alternatively, the first layered portion 21a in one concave-convex structure 31 may face a part of the first layered portion 21a and a part of the second layered portion 21b in the other concave-convex structure 31.

For example, by joining the concavo-convex structure 31 having the same period Pt of the convex portion 20b as the two concavo-convex structures 31, the optical device 30 in which the two resonance structure portions 18A and 18B have the same structural period Pk can be obtained. Can be formed. Further, for example, as two concave-convex structures 31, an optical device 30 in which the two resonance structure portions 18A and 18B have different structural periods Pk by joining the concave-convex structures 31 having different periodic Pts of the convex portions 20b. Can be formed.

The optical device 30 may include three or more resonance structure portions 18 arranged in the first direction. In a configuration in which the optical device 30 includes a plurality of resonance structure portions 18, if the structural period Pk of these resonance structure portions 18 is the same, the larger the number of resonance structure portions 18, the higher the intensity of the reflected light. Further, the plurality of resonance structure portions 18 may include a resonance structure portion 18 having the same structural period Pk and a resonance structure portion 18 having different structural periods Pk. According to such a configuration, it is possible to finely adjust the color of the reflected light and the transmitted light emitted from the optical device 30.

In manufacturing the optical device 30 having three or more resonance structure portions 18, the base material 11 of the concave-convex structure 31 and the concave-convex structure layer 20 are formed of a material capable of peeling the base material 11 from the concave-convex structure layer 20. .. Then, after the two concave-convex structures 31 are joined by the low-refractive index material, one base material 11 is peeled off, and the exposed concave-convex structure layer 20 and the other uneven structure 31 further form a low-refractive index material. By repeating the sandwiching and joining, the optical device 30 having 6 or more sub-wavelength lattices is formed.

As described above, according to the second embodiment, the following effects can be obtained in addition to the effects (1) to (7) of the first embodiment.
(8) According to the configuration in which the optical device 30 includes a plurality of resonance structure portions 18 arranged in the first direction, the optical device 10 includes four or more lattice regions 13 and 15, so that the wavelength selectivity of the optical device 30 is selective. It is possible to further increase the degree of freedom in adjusting the wavelength range included in the reflected light and the transmitted light.

(9) According to the configuration in which the structural periods Pk of the plurality of resonance structure portions 18 are the same in the plurality of resonance structure portions 18, the wavelength regions of the light causing resonance in each of the lattice regions 13 and 15 are the same, and each of the lattice regions 13 Since the reflected light in the specific wavelength range enhanced in, 15 is emitted from the optical device 30, the intensity of the light in the specific wavelength range emitted as the reflected light becomes higher, and the wavelength selectivity of the reflected light becomes higher. It will be higher.

(10) According to the configuration in which the structural period Pk of the first resonance structure portion 18A and the structural period Pk of the second resonance structure portion 18B are different from each other, resonance occurs in the lattice regions 13 and 15 of the first resonance structure portion 18A. The wavelength range of the light that causes resonance and the wavelength range of the light that causes resonance in the lattice regions 13 and 15 of the second resonance structure portion 18B are different from each other. Therefore, when light is incident on the optical device 30, the light in the first wavelength region enhanced in the lattice regions 13 and 15 of the first resonance structure portion 18A and the second resonance structure portion 18B are emitted from the optical device 30. The reflected light including the light in the second wavelength region enhanced in the lattice regions 13 and 15 possessed by the light is emitted. Further, among the wavelength ranges included in the incident light of 30 to the optical device, the light in the wavelength range excluding the first wavelength range and the second wavelength range emitted as the reflected light is transmitted from the optical device 10 as transmitted light. Be ejected. Therefore, in the optical device 30, it is possible to expand the wavelength range included in the reflected light and narrow the wavelength range included in the transmitted light while increasing the intensity of the reflected light. Therefore, the degree of freedom in adjusting the hue observed as reflected light or transmitted light can be increased by setting the lattice period of the sub-wavelength lattice of each of the resonance structure portions 18A and 18B.

(11) The optical device 30 is formed by having two concave-convex structures 31 face each other so that the high-refractive index layers 21 face each other, and filling a region between the two concave-convex structures 31 with a low-refractive index material. Will be done. According to this, the optical device 30 including the plurality of resonance structure portions 18 can be easily formed.

(Third Embodiment)
A method for manufacturing an optical device and a third embodiment of the optical device manufactured by this manufacturing method will be described with reference to FIGS. 17 and 18. In the third embodiment, the arrangement directions of the sub-wavelength lattices in the two resonance structures are different from those in the second embodiment. Hereinafter, the differences between the third embodiment and the second embodiment will be mainly described, and the same reference numerals will be given to the same configurations as those of the second embodiment, and the description thereof will be omitted. 17 and 18 are views showing a part of the optical device, and are composed of a portion made of a high refractive index material and a low refractive index material in order to make the structure of the optical device easy to understand. Dots with different densities are attached to the parts shown.

[Optical device configuration]
As shown in FIG. 17, the optical device 40 of the third embodiment includes two resonance structure portions 18A and 18B adjacent to each other in the first direction, similarly to the second embodiment. However, in the third embodiment, the respective element portions of the lattice regions 13 and 15 of the first resonance structure portion 18A, that is, the extending directions of the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b, respectively. , The extending directions of the respective element portions of the lattice regions 13 and 15 of the second resonance structure portion 18B are different from each other. That is, the direction in which the element portions are arranged in the lattice regions 13 and 15 is different for each resonance structure portion 18. In other words, the arrangement direction of the sub-wavelength lattice included in the first resonance structure portion 18A and the arrangement direction of the sub-wavelength lattice included in the second resonance structure portion 18B are different from each other.

The patterns of the four sub-wavelength lattices included in the optical device 40 are in agreement with each other, the periods P1 and P2 are all equal in the resonance structure portions 18A and 18B, the high element widths Dh1 and Dh2 are all equal, and the region thickness is T1 and T2 are all equal.

FIG. 18 is a diagram showing the optical device 40 shown in FIG. 17 divided into regions extending in a direction along the surface of the base material 11. Note that FIG. 18 is a diagram for clearly showing the arrangement of each element portion in the two resonance structure portions 18A and 18B, and the boundary of each region divided in FIG. 18 constitutes the optical device 40. It does not indicate the boundaries of the structures to be used.

As shown in FIG. 18, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b of the first resonance structure portion 18A extend along the second direction and are aligned along the third direction. On the other hand, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b of the second resonance structure portion 18B extend along the third direction and are aligned along the second direction. That is, the extending direction of each element portion of the first resonance structure portion 18A and the extending direction of each element portion of the second resonance structure portion 18B are orthogonal to each other. In other words, the angle formed by the arrangement direction of the sub-wavelength lattice of the first resonance structure portion 18A and the arrangement direction of the sub-wavelength lattice of the second resonance structure portion 18B is 90 °.

[Action of optical device]
When the sub-wavelength lattice is composed of high refractive index portions 13a and 15a extending in a band shape in one direction, light polarized in a specific direction is multiplely reflected and resonates in each of the lattice regions 13 and 15. It is emitted as reflected light. The specific direction depends on the arrangement direction of the sub-wavelength lattice. Since the arrangement directions of the sub-wavelength lattices are different between the first resonance structure portion 18A and the second resonance structure portion 18B, the lattice regions 13 and 15 of the first resonance structure portion 18A and the lattice regions of the second resonance structure portion 18B In 13 and 15, the polarization directions of the multiple reflected light are different from each other. Therefore, according to the optical device 40 of the third embodiment, the reflected light is efficiently emitted with respect to the incident light including the polarized light components in various directions, so that the intensity of the reflected light is further increased.

The configuration of the optical device 40 of the third embodiment may be applied to the wavelength selection filter 50 or may be applied to the display element included in the display body 60, as in the application example shown in the first embodiment. However, it may be applied to the sub-pixels included in the color filter 70.

However, in general, the incident light on the color filter 70 is light having the same polarization direction, whereas the incident light on the display body 60 is various like general lighting and sunlight. In many cases, the light contains a polarization component in the direction. Therefore, the effect is high when the configuration of the optical device 30 of the second embodiment is applied to the color filter 70, and the effect is high when the configuration of the optical device 40 of the third embodiment is applied to the display body 60. high.

[Manufacturing method of optical device]
Similar to the second embodiment, the optical device 40 of the third embodiment has two concave-convex structures 31 which are a structure composed of a base material 11, a concave-convex structure layer 20, and a high-refractive index layer 21 and have a high refractive index. The layers 21 are opposed to each other so as to face each other, and the region between the two concave-convex structures 31 is filled with a low refractive index material. Here, in the third embodiment, the extending direction of the high-refractive index layer 21 in one concave-convex structure 31 and the extending direction of the high-refractive index layer 21 in the other concave-convex structure 31 are orthogonal to each other. The concavo-convex structures 31 face each other and are joined by a low refractive index material.

The optical device 40 may include three or more resonance structure portions 18 arranged in the first direction, and the plurality of resonance structure portions 18 include resonance structure portions 18 in which the extension directions of the element portions are different from each other. Just do it. Such an optical device 40 has an even number, that is, 2n (n is an integer of 3 or more) sub-wavelength grids, and is 2m-1st (m is an integer of 1 or more and n or less) from a position close to one of the base materials 11. In the sub-wavelength lattice and the 2mth sub-wavelength lattice, the arrangement directions are the same and the lattice periods are the same. In other words, the optical device 40 has a structure in which pairs of sub-wavelength lattices having the same arrangement direction and lattice period are arranged in the first direction, and these sub-wavelength lattices are embedded in a low refractive index material. There is.

According to such a configuration, the polarization responsiveness of the optical device 40 can be set by setting the arrangement direction of the sub-wavelength lattice for each resonance structure unit 18, setting the number of resonance structure units 18 having the same arrangement direction of the sub-wavelength lattice, and the like. Can also be adjusted. The plurality of resonance structure portions 18 may include resonance structure portions 18 having different patterns of sub-wavelength lattices.

In manufacturing the optical device 40 having three or more resonance structure portions 18, the base material 11 and the uneven structure layer 20 of the concave-convex structure 31 are formed from a material capable of peeling the base material 11 from the concave-convex structure layer 20. .. Then, after the two concave-convex structures 31 are joined by the low-refractive index material, one base material 11 is peeled off, and the exposed concave-convex structure layer 20 and the other uneven structure 31 further form a low-refractive index material. By repeating the sandwiching and joining, the optical device 40 having 6 or more sub-wavelength lattices is formed.

As described above, according to the third embodiment, the following effects can be obtained in addition to the effects of (1) to (7) of the first embodiment and (8) and (11) of the second embodiment.
(12) Since the extending direction of the element portion of the first resonance structure portion 18A and the extending direction of the element portion of the second resonance structure portion 18B are different from each other, the lattice regions 13, 15 of the first resonance structure portion 18A In the lattice regions 13 and 15 of the second resonance structure unit 18B, among the light contained in the incident light, light polarized in different directions resonates and is emitted from the respective resonance structure units 18. Therefore, the reflected light is efficiently emitted from the incident light containing the polarized light components in various directions, so that the intensity of the reflected light is further increased.

[Modification example]
Each of the above embodiments can be modified and implemented as follows.
In the resonance structure portion 18 of the optical device manufactured by the manufacturing method of each of the above embodiments, the second low refractive index portion 15b is located above the first high refractive index portion 13a, and the first low refractive index portion 13b The second high refractive index portion 15a is located at the upper part.

That is, the arrangement pattern of the first high refractive index portion 13a matches the arrangement pattern of the second low refractive index portion 15b, and the arrangement pattern of the first low refractive index portion 13b is the second high refractive index portion 15a. Matches the placement pattern of. Then, in order to match the wavelength range of the light that causes resonance in the first lattice region 13 with the wavelength range of the light that causes resonance in the second lattice region 15, the first lattice region 13 and the second lattice region 15 are used. The lattice periods of the sub-wavelength lattices are the same, and the volume ratio of the plurality of first high refractive index portions 13a in the first lattice region 13 and the volume ratio of the plurality of second high refractive index portions 15a in the second lattice region 15 It is necessary that the ratio matches.

Satisfying these conditions is satisfied by the first high refractive index section 13a, the first low refractive index section 13b, the second high refractive index section 15a, and the second low refractive index section 15b, as in each of the above embodiments. The element portions have the same shape extending in a band shape in one common direction, and in each of the lattice regions 13 and 15, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b extend thereof. It is easy if the configuration is arranged alternately in the direction orthogonal to the direction.

However, as long as the above conditions are satisfied, each element portion may have a shape different from the shape extending in a band shape. For example, as shown in FIG. 19, each of the first high refractive index portion 13a, the first low refractive index portion 13b, the second high refractive index portion 15a, and the second low refractive index portion 15b is in the first direction. It has the same rectangular shape such as a square when viewed from the direction along the line, and in each of the lattice regions 13 and 15, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b are in the second direction and the third. The configuration may be arranged alternately along the respective directions. In such a case, as shown in FIG. 20, in the concave-convex structure layer 20, the convex portions 20b and the concave portions 20c are alternately arranged along each of the two directions orthogonal to each other, and the convex portions 20b and the concave portions are arranged in a plan view. 20c has the same rectangular shape such as a square.
According to the configuration shown in FIG. 19, even in one resonance structure portion 18, the reflected light is efficiently emitted with respect to the incident light including the polarizing components in various directions, so that the intensity of the reflected light is higher. Can be enhanced.

[Example]
The above-mentioned optical device and its manufacturing method will be described with reference to specific examples.

(Example 1)
The first embodiment is a wavelength selection filter to which an optical device is applied, and is a wavelength selection filter that selectively reflects light having a wavelength in the green band.
<Manufacturing of wavelength selection filter>
First, a mold, which is an intaglio plate used in the optical nanoimprint method, was prepared. Specifically, since light having a wavelength of 365 nm was used as the light to be irradiated in the optical nanoimprint method, synthetic quartz that transmits light of this wavelength was used as the material for the mold. In forming the mold, first, a film made of Cr was formed on the surface of the synthetic quartz substrate by a sputtering method, and an electron beam resist pattern of a sub-wavelength lattice pattern was formed on the Cr film by an electron beam lithography method. The sub-wavelength grid pattern is a pattern in which band-shaped portions extending in one direction are arranged at equal intervals. The resist used was a positive type, and the film thickness was 150 nm. The pattern drawn by an electron beam is a pattern in which a rectangle having a short side length of 180 nm and a long side length of 3 cm is arranged in a square region having a side of 3 cm with a period of 360 nm in the short side direction. The area where the line is drawn is the inner area of the rectangle. Next, the Cr film in the region exposed from the resist was etched by plasma generated by applying a high frequency to a mixed gas of chlorine and oxygen. Subsequently, the synthetic quartz substrate in the region exposed from the resist and the Cr film was etched by the plasma generated by applying a high frequency to the hexafluorinated ethane gas. The depth of the synthetic quartz substrate etched by this was 200 nm. The remaining resist and Cr film are removed, and Optool HD-1100 (manufactured by Daikin Industries, Ltd.) is applied as a mold release agent to obtain a mold in which sub-wavelength lattice patterns in which strips are arranged at equal intervals are formed in a square region. It was.

Next, an ultraviolet curable resin was applied to the square region on which the sub-wavelength lattice pattern was formed on the mold, and the mold surface was covered with a polyethylene terephthalate film that had been subjected to an easy-adhesion treatment. The ultraviolet curable resin was stretched using a roller so as to spread over the entire surface of the square region, irradiated with ultraviolet rays of 365 nm to cure the ultraviolet curable resin, and then the polyethylene terephthalate film was peeled off from the mold. As a result, a laminate of an uneven structure layer made of an ultraviolet curable resin having a sub-wavelength lattice pattern formed on the surface and a base material which is a polyethylene terephthalate film was obtained. The above steps were repeated to prepare two laminates of the concave-convex structure layer and the base material. The irradiation amount of ultraviolet rays at 365 nm was set to 50 mJ / cm ² .

Next, a high refractive index layer made of TiO ₂ was formed by forming a TiO ₂ film having a film thickness of 100 nm on the surfaces of the above two laminated bodies by a vacuum vapor deposition method. Subsequently, of the two laminates, the region where the sub-wavelength lattice pattern is located on the surface of one laminate is coated with an ultraviolet curable resin, and the coated ultraviolet curable resin is coated with the other laminate. The two laminates were faced to each other so that the surfaces were in contact with each other and the regions where the sub-wavelength grid patterns were located overlapped. The ultraviolet curable resin was spread using a roller so as to spread over the entire surface in the region where the sub-wavelength lattice pattern was located, and was irradiated with ultraviolet rays of 365 nm to cure the ultraviolet curable resin to form an embedded layer. As a result, the wavelength selection filter of Example 1 was obtained. The irradiation amount of ultraviolet rays at 365 nm was set to 50 mJ / cm ² .
<Evaluation of wavelength selection filter>
When the reflection spectroscopic measurement of the wavelength selection filter of Example 1 was carried out, a reflection spectrum having a center wavelength of about 530 nm was observed.

(Example 2)
The second embodiment is a display body in which an optical device is applied to pixels.
<Manufacturing of display body>
First, a mold, which is an intaglio plate used in the optical nanoimprint method, was prepared. Specifically, since light having a wavelength of 365 nm was used as the light to be irradiated in the optical nanoimprint method, synthetic quartz that transmits light of this wavelength was used as the material for the mold. In forming the mold, first, a film made of Cr was formed on the surface of the synthetic quartz substrate by a sputtering method, and an electron beam resist pattern having a sub-wavelength lattice pattern was formed on the Cr film by an electron beam lithography method. The sub-wavelength grid pattern is a pattern in which band-shaped portions extending in one direction are arranged at equal intervals. The resist used was a positive type, and the film thickness was 150 nm.

The pattern drawn by the electron beam is a pattern in which four types of sub-wavelength grid patterns are arranged. This pattern is schematically shown in FIG. The first pattern SP1 is a pattern in which strip-shaped portions are arranged in the X direction with a period of 360 nm in a square region having a side of 3 cm. The second pattern SP2 is a pattern in which strip-shaped portions are arranged in the Y direction orthogonal to the X direction with a period of 360 nm in a square region having a side of 3 cm. The third pattern SP3 is a pattern in which strip-shaped portions are arranged in the X direction with a period of 396 nm in a square region having a side of 3 cm. The fourth pattern SP4 is a pattern in which strip-shaped portions are arranged in the Y direction with a period of 396 nm in a square region having a side of 3 cm.

Next, the Cr film in the region exposed from the resist was etched by plasma generated by applying a high frequency to a mixed gas of chlorine and oxygen. Subsequently, the synthetic quartz substrate in the region exposed from the resist and the Cr film was etched by the plasma generated by applying a high frequency to the hexafluorinated ethane gas. The depth of the synthetic quartz substrate etched by this was 200 nm. The remaining resist and Cr film were removed, and Optool HD-1100 (manufactured by Daikin Industries, Ltd.) was applied as a mold release agent to obtain a mold in which the above four sub-wavelength lattice patterns were formed.

Next, an ultraviolet curable resin was applied to the region on the mold where the four sub-wavelength lattice patterns were formed, and the mold surface was covered with a polyethylene terephthalate film that had been subjected to an easy-adhesion treatment. The ultraviolet curable resin is spread using a roller so as to spread over the entire area where the sub-wavelength lattice pattern is formed, and is irradiated with ultraviolet rays of 365 nm to cure the ultraviolet curable resin, and then the polyethylene terephthalate film is formed from the mold. Was peeled off. As a result, an inverted sub-wavelength lattice pattern of the above four sub-wavelength lattice patterns is formed on the surface of the ultraviolet curable resin, and the concavo-convex structure layer made of the ultraviolet curable resin and the base material which is a polyethylene terephthalate film are formed. A laminate was obtained. The region in which each of the four sub-wavelength grid patterns is formed corresponds to the pixel portion. The above steps were repeated to prepare two laminates of the concave-convex structure layer and the base material. The irradiation amount of ultraviolet rays at 365 nm was set to 50 mJ / cm ² .

Next, a high refractive index layer made of TiO ₂ was formed by forming a TiO ₂ film having a film thickness of 100 nm on the surfaces of the above two laminated bodies by a vacuum vapor deposition method. Subsequently, of the two laminates, the region where the sub-wavelength lattice pattern is located on the surface of one laminate is coated with an ultraviolet curable resin, and the coated ultraviolet curable resin is coated with the other laminate. The two laminates were faced to each other so that the surfaces were in contact with each other and the regions where the sub-wavelength lattice patterns having the same period were located overlapped. The ultraviolet curable resin was spread using a roller so as to spread over the entire surface in the region where the sub-wavelength lattice pattern was located, and was irradiated with ultraviolet rays of 365 nm to cure the ultraviolet curable resin to form an embedded layer. As a result, the display body of Example 2 was obtained. The irradiation amount of ultraviolet rays at 365 nm was set to 50 mJ / cm ² .

<Evaluation of display>
When the reflection spectroscopic measurement of the display body of Example 2 was carried out, a reflection spectrum having a center wavelength of about 530 nm was observed in the pixel having a sub-wavelength lattice having a period of 360 nm, and a pixel having a sub-wavelength lattice having a period of 396 nm was about 620 nm. A reflection spectrum with a central wavelength was observed.

10, 30, 40 ... Optical device, 11 ... Base material, 12 ... First low refractive index region, 13 ... First lattice region, 13a ... First high refractive index portion, 13b ... First low refractive index portion, 14 ... 2nd low refractive index region, 15 ... 2nd lattice region, 15a ... 2nd high refractive index part, 15b ... 2nd low refractive index part, 16 ... 3rd low refractive index region, 17 ... 3rd high refractive index part, 18 ... Resonance structure part, 18A ... First resonance structure part, 18B ... Second resonance structure part, 20 ... Concavo-convex structure layer, 20a ... Flat part, 20b ... Convex part, 20c ... Concave part, 21 ... High refractive index layer, 21a ... 1st layered portion, 21b ... 2nd layered portion, 22 ... Embedded layer, 31 ... Concavo-convex structure, 50 ... Wavelength selection filter, 60 ... Display body, 60F ... Front surface, 60R ... Back surface, 61A ... 1st display area, 61B ... 2nd display area, 61C ... 3rd display area, 62A ... 1st pixel, 62B ... 2nd pixel, 62C ... 3rd pixel, 70 ... color filter, 71 ... pixel, 71R ... red sub-pixel, 71G ... Sub-pixel for green, 71B ... Sub-pixel for blue.

Claims (12)

A method for manufacturing an optical device composed of a material that transmits incident light.
On the surface of the layer made of the first low refractive index material, a plurality of convex portions arranged in a sub-wavelength period and concave portions alternately arranged with the convex portions along the arrangement direction of the plurality of convex portions, which are the same as the surface. A first step of forming a concave-convex structure layer having the convex portion and the concave portion by forming a plurality of concave portions having an area equal to the area of the plurality of convex portions when viewed from opposite directions.
Using a high refractive index material having a higher refractive index than the first low refractive index material, a high refractive index layer having a thickness smaller than the height of the convex portion is formed on the surface of the concave-convex structure layer. In two steps, as the high refractive index layer, a first sub-wavelength lattice located on the concave portion and a second sub located on the convex portion and having the same lattice period as the first sub-wavelength lattice. The second step of forming the layer including the wavelength lattice and
The structure is formed by forming an embedded layer made of a second low refractive index material having a refractive index lower than that of the high refractive index material on the surface of the structure composed of the uneven structure layer and the high refractive index layer. Includes a third step of filling the unevenness of the second sub-wavelength lattice with the second low refractive index material .
In the second step, the high refractive index layer is formed so that the high refractive index layer includes a high refractive index portion extending along the side surface of the convex portion.
Manufacturing method of optical device. In the first step, the intaglio is pressed against the coating layer made of the resin which is the first low refractive index material, the resin is cured, and then the intaglio is released to transfer the unevenness of the intaglio to the resin. By doing so, the uneven structure layer is formed.
In the second step, the high refractive index layer is formed by using a material containing an inorganic compound as the high refractive index material.
The third step according to claim 1, wherein the embedded layer is formed by applying a resin as the second low refractive index material to the surface of the structure and curing the applied resin. How to make an optical device. In the third step, the two structures are opposed to each other so that the high refractive index layers face each other, and the region between the two structures is filled with the second low refractive index material. The method for manufacturing an optical device according to claim 1 or 2, wherein the layer is formed. An optical device made of a material that transmits incident light.
It has a plurality of first high refractive index portions constituting the first sub-wavelength lattice, and a plurality of first low refractive index portions having a refractive index lower than that of the first high refractive index portion, and the first high refractive index portion. A first lattice region in which the first high refractive index portion and the first low refractive index portion are alternately located along the direction in which the rate portions are arranged,
A plurality of second high-refractive index sections made of the same material as the first high-refractive index section and forming a second sub-wavelength lattice, and a plurality of second high-refractive index sections having a lower refractive index than the second high-refractive index section. A second lattice region having two low refractive index portions, in which the second high refractive index portion and the second low refractive index portion are alternately located along the direction in which the second high refractive index portions are arranged.
The first low refractive index region, the second low refractive index region, and the third low refractive index, each of which has a refractive index lower than each of the average refractive index of the first lattice region and the average refractive index of the second lattice region. With a rate area,
The first lattice region is sandwiched between the first low refractive index region and the second low refractive index region in the thickness direction of the first lattice region.
The second lattice region is sandwiched between the second low refractive index region and the third low refractive index region in the thickness direction of the second lattice region.
The lattice period of the first sub-wavelength lattice and the lattice period of the second sub-wavelength lattice are equal periods to each other.
The volume ratio of the plurality of first high refractive index portions in the first lattice region is the same as the volume ratio of the plurality of second high refractive index portions in the second lattice region.
Seen from the direction along the thickness direction of the first lattice region
The first high refractive index portion and the second low refractive index portion overlap each other, and the second high refractive index portion and the first low refractive index portion overlap each other.
The second low refractive index region has a first high refractive index portion and a third high refractive index portion made of the same material as the second high refractive index portion.
The third high-refractive index portion is located between the ends of the first high-refractive index portion and the second high-refractive index portion, which are adjacent to each other when viewed from the direction along the thickness direction of the first lattice region. An optical device extending along the thickness direction of the second low refractive index region . The first low refractive index region, the first low refractive index portion, and the portion of the second low refractive index region adjacent to the first low refractive index portion are one structure that is continuous with each other. Is the first structure that is
The third low refractive index region, the second low refractive index portion, and the portion of the second low refractive index region adjacent to the second low refractive index portion are one structure that is continuous with each other. The optical device according to claim 4, which is the second structure. The difference in refractive index between the first structure, the first high refractive index portion, and the second high refractive index portion is larger than 0.2.
The optical device according to claim 5, wherein the difference in refractive index between the second structure, the first high refractive index portion, and the second high refractive index portion is larger than 0.2. The material constituting the first structure is any one of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin.
The material constituting the second structure is any one of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin.
The optical device according to claim 5 or 6, wherein the material constituting the first high refractive index portion and the second high refractive index portion contains an inorganic compound. Each of the plurality of first high refractive index portions, the plurality of first low refractive index portions, the plurality of second high refractive index portions, and the plurality of second low refractive index portions has one common direction. The optical device according to any one of claims 4 to 7 , which has a shape extending in a band shape. A portion composed of the first lattice region, the second lattice region, the first low refractive index region, the second low refractive index region, and the third low refractive index region is a resonance structure portion.
The optical device according to any one of claims 4 to 8 , wherein the optical device includes a plurality of the resonance structure portions arranged along the thickness direction of the resonance structure portion. The optical device according to claim 9 , wherein the lattice periods of the first sub-wavelength lattice and the second sub-wavelength lattice of each of the plurality of resonance structure portions are equal in the plurality of resonance structure portions. The plurality of resonance structure portions include a first resonance structure portion and a second resonance structure portion, and the lattice period of the first sub-wavelength lattice and the second sub-wavelength lattice of the first resonance structure portion. The optical device according to claim 9 , wherein the first sub-wavelength lattice and the lattice period of the second sub-wavelength lattice of the second resonance structure are different from each other. In each of the plurality of resonance structure portions, the plurality of first high refractive index portions, the plurality of first low refractive index portions, the plurality of second high refractive index portions, and the plurality of second low refractive index portions. Each element portion of the portion has a shape extending in a band shape in one direction.
The plurality of resonance structure portions include a first resonance structure portion and a second resonance structure portion.
The optical device according to claim 9 , wherein the extending direction of the element portion of the first resonance structure portion and the extending direction of the element portion of the second resonance structure portion are different from each other.