JP4760135B2 - Optical device and optical device manufacturing method - Google Patents

Description

  The present invention relates to an optical device that selectively polarizes incident light and a manufacturing method thereof.

There is known an optical device having a so-called wire grid structure in which a plurality of linear metal layers parallel to each other are formed on a substrate at a narrower interval than the wavelength of incident light.
As shown in FIGS. 18A and 18B, the optical device includes a plurality of metal layers 103 that are parallel to each other on one main surface of a substrate 102 that is transparent with respect to the visible light region. The line-shaped grid has a configuration that is formed at a narrower interval than the wavelength of the incident light L, and is incident at a predetermined incident angle θ _in on the normal line (shown by a broken line) of the main surface of the substrate 102. of the incident light L, and the vertical polarization components a grid, selectively transmit a main polarization component c constituting the transmitted light L _1, polarization components b parallel to the grid 103, constitutes a reflected light L ₂ This is selectively reflected as the main polarization component d.

However, in the optical device 101 having this wire grid structure, it is difficult to form the grid with the metal layer 103 so that the interval between the linear grids is shorter than the short wavelength side of the visible light region, for example, less than 0.6 μm. parallel polarization components or mixed partially transmitted light L ₁ (figure e), the vertical polarization component to the grid will be become intermixed part on the reflected light L ₂ (in the figure f).
For this reason, in the optical device having the wire grid structure, although the main polarization components of the transmitted light L ₁ and the reflected light L ₂ can be selected, the incident light L is completely selectively polarized, that is, polarized light is separated. Is considered difficult.

On the other hand, an optical device has been proposed in which the polarization separation characteristics are improved by selecting the material and shape of the substrate 102 and the metal layer 103 constituting the optical device having a wire grid structure (for example, Patent Document 1). reference).
Special table 2003-508813 gazette

However, only with the invention described in Patent Document 1, there is a possibility that the above-described improvement of the polarization separation characteristic is not sufficiently performed.
For example, as an optical device according to the invention described in Patent Document 1, for example, the substrate 102 and the metal layer 103 are made of SiO ₂ and Al (aluminum), respectively, the grid interval, that is, the pitch length is 144 nm, and the thickness of the metal layer 103. Is 170 nm, the width of the metal layer 103 is set to a ratio of 0.45 to the pitch length, and the incident angle θ _in of incident light is selected to be 45 °, the transmitted light and reflected light generated through the optical device 1 are related. The following problems occur with respect to polarization separation characteristics.

19A and 19B show the transmittance of the transmitted light L ₁ (shown by a broken line) and the reflectance of the reflected light L ₂ for the polarization component perpendicular to the grid and the polarization component parallel to the grid, respectively, in this conventional optical device. The measurement result (shown by a solid line) is shown.
As for the polarization component parallel to the grid, as shown in FIG. 19B, transmitted light is almost completely suppressed regardless of the wavelength band of visible light, but for the polarization component perpendicular to the grid, as shown in FIG. 19A. In particular, since the transmittance of the transmitted light is decreased and the reflectance of the reflected light is increased in the short wavelength region of 0.6 μm or less, the reflected light has a large wavelength dependency and a polarization component that is parallel to the grid as a main polarization component. It can also be confirmed that a part of the polarization component perpendicular to the grid is mixed.

20A and 20B show the extinction ratio of reflected light (reflected light of polarized light parallel to the grid / reflected light of polarized light perpendicular to the grid) and the extinction ratio of transmitted light (grid) in this conventional optical device, respectively. (Measurement result of polarized transmitted light perpendicular to the grid / transmitted light polarized parallel to the grid).
Also from these measurement results, as shown in FIG. 20A, it can be seen that the extinction ratio of the reflected light does not increase particularly in the short wavelength region, and the wavelength dependence remains strong. Such wavelength dependence is required to be reduced as much as possible, for example, when a display device or the like is constituted by an optical device, which causes a decrease in luminance and contrast and generation of color spots.

  In view of the above-described problems, the present invention provides an optical device with improved polarization separation characteristics and a method for manufacturing the optical device.

An optical device according to the present invention is an optical device that selectively polarizes incident light, and is formed on a substrate made of SiO ₂ and having a grid-like concavo-convex structure on a surface and a convex portion of the concavo-convex structure of the substrate. , A grid-like metal layer made of Al, and a dielectric layer made of SiO ₂ or a material having a higher refractive index than that formed on the metal layer, the thickness of the metal layer being 170 nm, with a grid interval The pitch length is 144 nm, the width is 0.45 with respect to the pitch length, and the thickness of the dielectric layer is 100 nm .

The method for manufacturing an optical device according to the present invention is a method for manufacturing an optical device that selectively polarizes the incident light described above. This manufacturing method includes a step of forming a metal layer made of Al with a thickness of 170 nm on the surface of a substrate made of SiO ₂ , and a resist made of a dielectric material having a refractive index of SiO ₂ or higher on the metal layer. Forming a layer with a thickness of 100 nm, patterning the resist layer in a linear grid pattern with a pitch length of 144 nm and a width of 0.45 with respect to the pitch length, and the patterned resist Patterning the metal layer into a linear grid by anisotropic etching using the layer as an etching mask, and forming a recess on the surface of the substrate by anisotropic etching using the resist layer as an etching mask; It is characterized by including.

  According to the optical device of the present invention, in the optical device that selectively polarizes incident light, the substrate that is transparent at least with respect to the visible light region and the main surface of the substrate are provided in parallel to each other and spaced from each other. Has a plurality of linear metal layers that are smaller than the wavelength of the incident light, and at least a dielectric layer is formed on the opposite side of the metal layer from the substrate, so that the short wavelength The polarization separation characteristic with respect to the incident light in the region, that is, the polarization separation efficiency is improved.

  According to the optical device of the present invention, the metal layer forming step of forming a metal layer on one main surface of the substrate transparent with respect to the visible light region, and the metal layer shaping that shapes at least the metal layer into a plurality of straight lines parallel to each other. And a dielectric layer forming step of forming a dielectric layer at least on the opposite side of the metal layer from the substrate, it is possible to manufacture an optical device with improved polarization separation characteristics Become.

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

<First Embodiment of Optical Device>
A first embodiment of an optical device according to the present invention will be described.
1A and 1B are a schematic perspective view and a schematic cross-sectional view showing a configuration of an optical device according to the present embodiment.
As shown in FIG. 1A, the optical device 1 according to the present embodiment includes a plurality of metal layers 3 parallel to each other on a principal surface of a substrate 2 that is transparent at least in the visible light region. The dielectric layer 4 is formed at an interval which is made smaller than the wavelength of the incident light L ′ and at least on the opposite side of the metal layer 3 from the substrate 2, that is, for example, in contact with the upper surface. Have

In the present embodiment, the substrate 2, the metal layer 3, and the dielectric layer 4 are made of SiO ₂ , Al (aluminum), and SiO ₂ , respectively, and the grid interval, that is, the pitch length of the metal layer 3 is 144 nm. 3 is set to 170 nm, the width of the metal layer 3 is set to a ratio of 0.45 to the pitch length, the incident angle θ _in of incident light is selected to be 45 °, and the thickness of the dielectric layer 4 is set to 100 nm. .

In the optical device 1 according to the present embodiment, out of the incident light L incident at a predetermined incident angle θ _in with respect to the normal line (broken line) of the main surface of the substrate 2, the polarization component a ′ perpendicular to the grid is generated. , Selectively transmit as the main polarization component c ′ constituting the transmitted light L ₁ ′, and selectively reflect the polarization component b ′ parallel to the grid 103 as the main polarization component d ′ constituting the reflected light L ₂ ′. However, the provision of the dielectric layer 4 on the upper surface of the metal layer 3 improves the polarization separation characteristics such as transmittance, reflectance and extinction ratio, as will be described later.

2A and 2B show the transmitted light for the polarization components (a ′ and c ′) perpendicular to the grid and the polarization components (b ′ and d ′) parallel to the grid, respectively, in the optical device 1 according to this embodiment. The measurement results of the transmittance (illustrated by broken lines) and the reflectance of the reflected light (shown by solid lines) are shown. The measurement was performed for a wavelength range of 0.4 μm to 0.8 μm, which is generally called a visible light region.
According to the optical device 1 according to the present embodiment, as shown in FIG. 2B, the transmitted light is substantially completely suppressed regardless of the wavelength band of visible light, and the polarization component parallel to the grid is perpendicular to the grid. As for the polarization component, as shown in FIG. 2A, compared to the case of the conventional optical device described above, the decrease in the transmittance of the transmitted light and the increase in the reflectance of the reflected light are suppressed particularly in the short wavelength region of 0.6 μm or less. Is done. Therefore, it can be confirmed that the mixing of the polarization component perpendicular to the grid with respect to the reflected light having the polarization component parallel to the grid as the main polarization component is reduced along with the suppression or improvement of the wavelength dependency.

FIG. 3 shows the measurement result of the polarization component in the optical device 1 according to the present embodiment shown in FIG. 2A and the measurement result of the polarization component in the conventional optical device 101 shown in FIG. It is.
In FIG. 3, the reflectance of the reflected light and the transmittance of the transmitted light by the optical device 1 according to this embodiment are indicated by a solid line g and a solid line i, respectively, and the reflectance of the reflected light and the transmission of the transmitted light by the conventional optical device 101 are illustrated. The rates are indicated by broken lines h and j, respectively.

According to the optical device 1 according to the present embodiment, as compared with the case of the conventional optical device 101, for example, with respect to incident light having a wavelength of 0.5 μm, the reflectance of the polarization component perpendicular to the grid is about 0.03. It can be confirmed that the transmittance is reduced and the transmittance is increased by about 0.02. That is, according to the optical device 1 according to the present embodiment, the polarization component parallel to the grid is mixed with the transmitted light L ₁ ′ having the polarization component perpendicular to the grid as the main polarization component shown in FIG. 1A (e ′ in the figure). ) Is suppressed, but mixing of the polarization component perpendicular to the grid (f ′ in the figure) with respect to the reflected light L ₂ ′ having the polarization component parallel to the grid as the main polarization component is reduced, and the wavelength dependence in the visible light region is reduced. It can be seen that is improved.

4A and 4B show the extinction ratio of reflected light (reflected light of polarized light parallel to the grid / reflected light of polarized light perpendicular to the grid) and the extinction ratio of transmitted light (in the optical device 1 according to this embodiment, respectively). The measurement result of polarized light transmitted perpendicular to the grid / transmitted light polarized parallel to the grid is shown.
The extinction ratio, that is, the extinction ratio is an intensity ratio of polarized light orthogonal to each other, and it is considered that the larger the value, the better the polarization separation characteristic (polarization selectivity).

According to the optical device 1 according to the present embodiment, as shown in FIG. 4A, the extinction ratio of the reflected light is extended in the entire wavelength band, and the extension is particularly large in the short wavelength range. For example, the conventional apparatus shown in FIG. Compared to the case of using the optical device 101, for example, about 150 extinction ratios are improved for incident light having a wavelength of 0.6 μm.
From this measurement result, it was confirmed that the wavelength dependency was suppressed and the polarization separation characteristic was improved by the configuration of the present invention. It is considered that the occurrence of spots is reduced.

  In the present embodiment, the shape of the dielectric layer 4 on the metal layer 3 is schematically shown as a plate shape or a rectangular parallelepiped shape, but may be formed in a trapezoidal cross section as shown in FIG. However, as described later, the cross-sectional shape may be formed as a substantially semicircular shape or polygonal shape other than a quadrangle. For example, as shown in FIG. 6, the dielectric layer 4 may be formed wider than the metal layer 3.

<Second Embodiment of Optical Device>
A second embodiment of the optical device according to the present invention will be described.
In the second embodiment, only portions different from the first embodiment will be described. Portions that are not described are the same as those in the first embodiment. For the sake of explanation, the same reference numerals are given to the same components as those in the first embodiment, and the duplicate description is omitted.

FIG. 7 is a schematic cross-sectional view showing the configuration of the optical device according to the present embodiment.
In the optical device 1 according to this embodiment, a plurality of metal layers 3 parallel to each other are formed as linear or line-like grids on one main surface of a substrate 2 transparent at least in the visible light region. The dielectric layer 4 is formed at least on the side opposite to the substrate 2 of the metal layer 3.
Further, in the optical device 1 according to this embodiment, a groove parallel to the grid of the metal layer 3 is formed in the exposed portion of the substrate 2 on the main surface side where the metal layer 3 is provided. It has a configuration in which the unevenness having a depth larger than the sum of the thicknesses of the metal layer 3 and the dielectric layer 4 is formed by the unevenness.

FIGS. 8A and 8B respectively show the transmittance of transmitted light (shown by a broken line) and the reflectance of reflected light (with respect to a polarization component perpendicular to the grid and a polarization component parallel to the grid) in the optical device 1 according to the present embodiment. The measurement result of a solid line is shown.
According to the optical device 1 according to the present embodiment, as shown in FIG. 8B, transmitted light is substantially completely suppressed regardless of the wavelength band of visible light, and the polarization component parallel to the grid is perpendicular to the grid. As for the component, as shown in FIG. 8A, the polarization component parallel to the grid is further suppressed in the short wavelength region in which the decrease in the transmittance of the transmitted light and the increase in the reflectance of the reflected light are suppressed as compared with the configuration in the first embodiment described above. It can be confirmed that the mixing of the polarization component perpendicular to the grid with respect to the reflected light having the main polarization component is reduced.

9A and 9B show the extinction ratio of reflected light (reflected light of polarized light parallel to the grid / reflected light of polarized light perpendicular to the grid) and the extinction ratio of transmitted light (in the optical device 1 according to this embodiment, respectively). The measurement result of polarized light transmitted perpendicular to the grid / transmitted light polarized parallel to the grid is shown.
As shown in FIG. 9A, the extinction ratio of reflected light is increased particularly in a short wavelength region. For example, the extinction ratio on the short wavelength side is increased as compared with the case of the configuration in the first embodiment described above. For incident light with a wavelength of 0.5 μm, it can be confirmed that the extinction ratio is improved by about 100, the uniformity is further increased over the entire wavelength band, and the wavelength dependency is reduced.
From this measurement result, it was confirmed that the wavelength dependency was suppressed and the polarization separation characteristic was improved by the configuration of the present invention. It is considered that the occurrence of spots is reduced.

  Further, in the present embodiment, the shape of the dielectric layer 4 on the metal layer 3 is schematically shown as a plate shape or a rectangular parallelepiped shape. However, for example, as shown in FIGS. For example, as shown in FIG. 12, the shape of a recess, that is, a groove formed on the surface of the substrate 2 can be selected as appropriate.

<Third Embodiment of Optical Device>
A third embodiment of the optical apparatus according to the present invention will be described.
In the third embodiment, only parts different from the first embodiment will be described. Portions that are not described are the same as those in the first embodiment. For the sake of explanation, the same reference numerals are given to the same components as those in the first embodiment, and the duplicate description is omitted.

FIG. 13 is a schematic cross-sectional view showing the configuration of the optical device according to the present embodiment.
In the optical device 1 according to this embodiment, a plurality of metal layers 3 parallel to each other are formed as linear or line-like grids on one main surface of a substrate 2 transparent at least in the visible light region. The dielectric layer 4 is formed at least on the side opposite to the substrate 2 of the metal layer 3.
Further, in the optical device 1 according to the present embodiment, the second dielectric layer 5 is provided between the substrate 2 and the metal layer 3, and the metal layer 3 and the dielectric are formed by the second dielectric layer 5. It has a configuration in which irregularities having a depth greater than the sum of the thicknesses of the layers 4 are formed.

  In the optical device 1 according to the present embodiment, the uneven protrusions formed on the main surface side where the metal layer 3 is provided are formed by the second dielectric layer 5 provided between the metal layer 3 and the substrate 2. Although the example which comprises is demonstrated, it is not restricted to this. For example, a configuration in which the second dielectric layer 5 is provided also in a grid interval portion, that is, a pitch portion of the metal layer 3, and the concave portion may be formed by at least a part of the second dielectric layer 5. .

In the optical device 1 according to the present embodiment, although not shown, in the measurement of the extinction ratio of the reflected light and the transmitted light, it is possible to confirm the same tendency as in the optical device according to the second embodiment described above. did it.
Therefore, the optical device according to the present embodiment can also suppress the wavelength dependency and improve the polarization separation characteristic. For example, even when a display device is configured, the luminance and contrast are reduced, and color spots are generated. It is thought to be reduced.

In the first to third embodiments described above, the thickness of the dielectric layer 4 is set to 100 nm. However, the thickness is not limited to this. For example, the thickness is set to 10 nm or 1 mm. As far as the thickness of the dielectric layer 4 is concerned, it was confirmed that the polarization splitting characteristics were improved by improving the extinction ratio.
As for the extinction ratio when the thickness of the metal layer 3 is 170 nm, it is particularly preferable that the thickness of the dielectric layer 4 is about 100 nm, and then the extinction ratio is greatly improved in the order of 300 nm, 500 nm, and 10 nm. In addition, when the refractive index of the dielectric layer 4 is higher than the refractive index of the substrate 2, the extinction ratio is particularly improved, and the refractive index of the dielectric layer 4 is higher than the refractive index of the substrate 2. It was confirmed that the extinction ratio was improved as compared with the case of the conventional configuration even when the ratio was low.

In addition to the above-described SiO ₂ , various materials including organic substances can be used as the material constituting the dielectric layer 4 and the second dielectric layer 5, but the dielectric material is transparent in the visible light range. Among these, it is preferable to select based on the refractive index, transmittance, absorptivity, and the like. For example, various dielectrics can be used including oxides such as titanium oxide, alumina, bismuth oxide, and tungsten oxide, and fluorides such as calcium fluoride, lithium fluoride, and magnesium fluoride.
In the optical device 1 according to the present invention, the dielectric layer 4 may be formed of a multilayer film, or the metal layer 3 and the dielectric layer 4 may be repeatedly stacked.

<First Embodiment of Manufacturing Method of Optical Device>
A first embodiment of a method of manufacturing an optical device according to the present invention will be described with reference to FIGS. 14A to 14D.
In the method for manufacturing an optical device according to the present embodiment, first, a substrate 2 that is transparent in the visible light region is prepared, and a metal layer 3 made of, for example, aluminum is formed on one main surface of the substrate 2 by, for example, vapor deposition. A layer forming step is performed, and as shown in FIG. 14A, a resist 6 is deposited and formed so as to correspond to a region where the metal layer 3 is finally left by, for example, a lithography method using an electron beam drawing apparatus or a nanoimprint apparatus.

  Subsequently, anisotropic etching is performed on the metal layer 3 through, for example, RIE (Reactive Ion Etching) using a chlorine-based gas through the opening of the resist 6, and the metal layer 3 is formed into a plurality of straight lines parallel to each other as shown in FIG. 14B. A metal layer shaping step for shaping the film is performed.

Subsequently, as shown in FIG. 14C, the resist 6 is peeled and removed, and a dielectric layer 4 made of, for example, SiO ₂ is formed on the opposite side of the metal layer 3 from the substrate 2 such as the upper surface of the metal layer 3 by, for example, vapor deposition. By performing the body layer forming step, the optical device 1 as shown in FIG. 14D is obtained.

<Second Embodiment of Manufacturing Method of Optical Device>
A second embodiment of the method of manufacturing an optical device according to the present invention will be described with reference to FIGS. 15A to 15C.
In the second embodiment, parts that will not be described are the same as those in the first embodiment, and for the sake of explanation, the same reference numerals are given to the same constituent elements as those in the first embodiment, and the description is repeated. Is omitted.

  In the method of manufacturing an optical device according to the present embodiment, first, a transparent substrate 2 is prepared with respect to the visible light region, and a metal layer forming step of forming a metal layer 3 of, for example, aluminum on one main surface of the substrate 2 is performed. Then, as shown in FIG. 15A, a resist 7 made of a dielectric material is deposited to correspond to a region where the metal layer 3 is finally left, and a dielectric layer forming step is performed.

  Subsequently, an opening is formed in the resist 7 that finally becomes the dielectric layer by, for example, RIE using a fluorine-based gas, and the metal layer 3 is etched through this opening by, for example, RIE using a chlorine-based gas, as shown in FIG. 15B. As described above, a metal layer shaping step for shaping the metal layer 3 into a plurality of straight lines parallel to each other is performed.

  Subsequently, a resist 7 made of a dielectric is formed as a dielectric layer 4 with a predetermined thickness and shape by etching, for example, and an unevenness is formed on the main surface of the substrate 2 by the metal layer 3 and the dielectric layer 4. An optical device 1 as shown in FIG. 15C is obtained.

  According to the manufacturing method of the optical device according to the present embodiment, since the dielectric layer forming step is performed prior to the metal layer shaping step, the dielectric layer can be used as an etching mask in the metal layer shaping step. Costs can be reduced and the number of processes can be reduced.

<Third Embodiment of Optical Device Manufacturing Method>
A third embodiment of the method of manufacturing an optical device according to the present invention will be described with reference to FIGS. 16A to 16C.
In the third embodiment, parts that will not be described are the same as those in the first embodiment, and for the sake of explanation, the same reference numerals are given to the same constituent elements as those in the first embodiment, and the description is repeated. Is omitted.

  In the method of manufacturing an optical device according to the present embodiment, first, a transparent substrate 2 is prepared with respect to the visible light region, and a metal layer forming step of forming a metal layer 3 of, for example, aluminum on one main surface of the substrate 2 is performed. As shown in FIG. 16A, a dielectric layer 7 is formed by depositing a resist 7 corresponding to the region where the metal layer 3 is finally left.

  Subsequently, an opening is formed in the resist 7 which finally becomes a dielectric layer by, for example, RIE using a fluorine-based gas, and the metal layer 3 is formed into a plurality of straight lines parallel to each other through this opening by, for example, RIE using a chlorine-based gas. A metal layer shaping step is performed, and a recess having a depth larger than the sum of the thicknesses of the metal layer 3 and the resist 7 that finally constitutes the dielectric layer of the optical device is formed.

  Subsequently, by forming a resist 7 made of a dielectric, for example, by etching to a predetermined thickness and shape as a dielectric layer 4, predetermined irregularities are formed on the main surface of the substrate 2, as shown in FIG. 16C. An optical device 1 is obtained.

  According to the method for manufacturing an optical device according to the present embodiment, not only the dielectric layer forming step is performed prior to the metal layer shaping step, but also the shaping of the metal layer 3 and the formation of the recesses on the surface of the substrate 2 can be performed simultaneously. Therefore, the dielectric layer can be used as an etching mask in the metal layer shaping process, and the main surface of the optical device finally obtained by the unevenness having a desired depth and shape can be formed with a small number of processes. It becomes possible.

<Fourth Embodiment of Manufacturing Method of Optical Device>
A fourth embodiment of the method of manufacturing an optical device according to the present invention will be described with reference to FIGS. 17A to 17C.
In the fourth embodiment, parts that will not be described are the same as those in the first embodiment, and for the sake of explanation, the same components as those in the first embodiment are denoted by the same reference numerals and redundant description is given. Is omitted.

In the method of manufacturing an optical device according to this embodiment, first, a substrate 2 that is transparent in the visible light region is prepared, and is formed on one main surface of the substrate 2 on the metal layer 3 of the optical device that is finally obtained. After the second dielectric layer 5 made of, for example, SiO ₂ is formed by, for example, vapor deposition, which is different from the dielectric layer to be formed, a metal layer forming step for forming the metal layer 3 made of, for example, aluminum is performed, as shown in FIG. Finally, a dielectric resist 7 is deposited corresponding to the region where the metal layer 3 is left, and a dielectric layer forming step is performed.

Subsequently, etching is performed through the metal layer 3 and the second dielectric layer 5 and stopping at the substrate 2 through the opening of the resist 7 which finally becomes the dielectric layer, and as shown in FIG. A metal layer shaping step for shaping 3 into a plurality of straight lines parallel to each other, and a depth larger than the sum of the thicknesses of the metal layer 3 and the resist 7 that finally constitutes the dielectric layer of the optical device A recess is formed.
In the present embodiment, the second dielectric layer 5 in the region corresponding to the resist 7 is completely removed. However, a recess may be formed by the second dielectric layer 5 while leaving a part thereof. The etching reaches the substrate 2, that is, the substrate 2 is partially removed to form a recess, and thereby the optical device finally obtained can be formed with unevenness deeper than the sum of the metal layer and the dielectric layer. .

  Subsequently, by forming a resist 7 made of a dielectric, for example, by etching into a dielectric layer 4 having a predetermined thickness and shape, predetermined irregularities are formed on the main surface of the substrate 2 and shown in FIG. 17C. Such an optical device 1 is obtained.

  According to the method for manufacturing an optical device according to the present embodiment, not only the dielectric layer forming step is performed prior to the metal layer shaping step, but also the second dielectric layer 5 is provided between the metal layer 3 and the substrate 2. The main surface of the optical device finally obtained can be constituted by the unevenness having a desired depth and shape.

The embodiments of the optical device and the method for manufacturing the optical device according to the present invention have been described above, but the present invention is not limited to this.
For example, in the above-described embodiment, the example in which vapor deposition is used as the formation method of the metal layer, the dielectric layer, and the second dielectric layer has been described. However, for example, a thin film formation method such as sputtering or MBE (Molecular Beam Epitaxy) Various changes and modifications can be made to the present invention.

A and B are a schematic perspective view and a schematic cross-sectional view, respectively, showing the configuration of an example of an optical device according to the present invention. FIGS. 7A and 7B are schematic diagrams illustrating measurement results of transmittance of transmitted light and reflectance of reflected light with respect to a polarization component perpendicular to the grid and a polarization component parallel to the grid, respectively, in the configuration of an example of the optical device according to the present invention. FIGS. It is. It is an expansion schematic diagram which shows the measurement result of the transmittance | permeability of the transmitted light and the reflectance of reflected light with respect to the polarization component perpendicular | vertical to a grid in the structure of an example of the optical apparatus which concerns on this invention. A and B are schematic views showing measurement results of the extinction ratio of reflected light and the extinction ratio of transmitted light in the configuration of an example of the optical device according to the present invention. It is a schematic sectional drawing which shows the other example of the optical apparatus which concerns on this invention. It is a schematic sectional drawing which shows the other example of the optical apparatus which concerns on this invention. It is a schematic sectional drawing which shows the other example of the optical apparatus which concerns on this invention. A and B respectively show the measurement results of the transmittance of the transmitted light and the reflectance of the reflected light with respect to the polarization component perpendicular to the grid and the polarization component parallel to the grid in the configuration of another example of the optical device according to the present invention. It is a schematic diagram. A and B are schematic views showing measurement results of the extinction ratio of reflected light and the extinction ratio of transmitted light in the configuration of another example of the optical device according to the present invention. It is a schematic sectional drawing which shows the other example of the optical apparatus which concerns on this invention. It is a schematic sectional drawing which shows the other example of the optical apparatus which concerns on this invention. It is a schematic sectional drawing which shows the other example of the optical apparatus which concerns on this invention. It is a schematic sectional drawing which shows the other example of the optical apparatus which concerns on this invention. AD is process drawing for description of an example of the manufacturing method of the optical apparatus which concerns on this invention. FIGS. 8A to 8C are process diagrams for explaining another example of the method for manufacturing an optical device according to the present invention. FIGS. FIGS. 8A to 8C are process diagrams for explaining another example of the method for manufacturing an optical device according to the present invention. FIGS. FIGS. 8A to 8C are process diagrams for explaining another example of the method for manufacturing an optical device according to the present invention. FIGS. A and B are a schematic perspective view and a schematic cross-sectional view showing a configuration of a conventional optical device, respectively. FIGS. 7A and 7B are schematic diagrams illustrating measurement results of transmittance of transmitted light and reflectance of reflected light with respect to a polarization component perpendicular to the grid and a polarization component parallel to the grid, respectively, in the configuration of the conventional optical device. A and B are schematic diagrams showing measurement results of the extinction ratio of reflected light and the extinction ratio of transmitted light in the configuration of a conventional optical device, respectively.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical apparatus, 2 ... Board | substrate, 3 ... Metal layer, 4 ... Dielectric layer, 5 ... 2nd dielectric layer, 6 ... Resist, 7 ... Resist (Dielectric layer), 101 ... Conventional optical device, 102 ... Substrate, 103 ... Metal layer

Claims (2)

An optical device that selectively polarizes incident light,
A substrate made of SiO ₂ and having a grid-like uneven structure on the surface;
A grid-like metal layer made of Al, formed on the convex portion of the concave-convex structure of the substrate,
A dielectric layer formed on the metal layer and made of SiO ₂ or a material having a higher refractive index,
The thickness of the metal layer is 170 nm, the pitch length that is the grid interval is 144 nm, and the width is a ratio of 0.45 to the pitch length,
An optical device, wherein the dielectric layer has a thickness of 100 nm. Forming a metal layer made of Al with a thickness of 170 nm on the surface of the substrate made of SiO ₂ ;
Forming a resist layer made of SiO ₂ or a dielectric material having a higher refractive index on the metal layer with a thickness of 100 nm;
Patterning the resist layer in a linear grid pattern with a pitch length of 144 nm and a width of 0.45 with respect to the pitch length;
Patterning the metal layer into a linear grid by anisotropic etching using the patterned resist layer as an etching mask;
Forming a recess in the surface of the substrate by anisotropic etching using the resist layer as an etching mask.
A method of manufacturing an optical device that selectively polarizes incident light .

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