WO2018155556A1 - Photonic crystal - Google Patents

Abstract

[Problem] To provide a photonic crystal having high light-reflecting properties. [Solution] A photonic crystal 6 having a substrate layer 2 having protrusions 3, and a surface layer 1 disposed on the surface of the substrate layer 2 having the protrusions 3, wherein the surface layer 1 contains a guanidine derivative. A method for manufacturing a photonic crystal 6, comprising heating a guanidine derivative and thereby vaporizing the guanidine derivative, forming the guanidine derivative on the surface of a substrate layer 2 of a photonic crystal 6 having protrusions 3, and arranging a surface layer 1 containing the guanidine derivative on the surface of the protrusions 3 of the substrate layer 2.

Description

Photonic crystal

The present invention provides, for example, a photonic crystal.

A photonic crystal is a nanostructure whose refractive index changes periodically in the order of the wavelength of light. Since the photonic crystal can freely control the path of light, research is mainly conducted in the field of optoelectronics such as information communication and information processing.

When the surface shape is optimized such that the height and pitch of the convex portions on the surface are set to 100 to 800 nm, the photonic crystal shows the characteristic of reflecting incident light as monochromatic visible light. As an optical sensor applying the light reflectivity found in such a photonic crystal, a POCT product or the like has been studied, and in recent years, a photonic crystal has attracted attention in the biodevice field.

POCT is an abbreviation for Point of Care Test. POCT is a POCT guideline issued by the Japanese Society for Clinical Laboratory Automation. It is a test performed by the subject or a test performed by the subject himself. The test time can be shortened and the test can be performed at the test location (test visible to the subject). It is defined as an inspection having the advantage of A test reagent used at the time of POCT is called a POCT product.

Patent Document 1 describes an example of a POCT product to which a resin photonic crystal is applied. In researches in which photonic crystals are applied to POCT products, since cost reduction at the time of commercialization is taken into consideration, inexpensive resin or glass is often used as a raw material. A specific application method assumes that a photonic crystal is used for the antigen detection part of the POCT product, and the intensity or wavelength of reflected light that changes depending on the presence or absence of the antigen is judged by human vision.

Patent Document 1 uses a photonic crystal made of resin such as polyvinyl chloride (PVC). Resin-made photonic crystals have low reflected light intensity. That is, since the refractive index of the resin used for the photonic crystal is as small as 1.5, the light reflectance and the intensity of the reflected light are small. As a result, there has been a problem that slight changes in reflected light due to the presence or absence of an antigen cannot be recognized by human vision.

Patent Document 2 describes a method for forming a thin film having a high refractive index. In Patent Document 2, a thin film having a high refractive index is formed by a method that does not require conditions such as high vacuum, in which guanidine carbonate as a raw material is heated and evaporated on a substrate. Forming a thin film having a high refractive index on a substrate can be said to be one method for easily changing the light reflectivity of the substrate surface. Patent Document 2 does not describe a photonic crystal.

U.S. Patent No. 6,057,049 describes a photonic crystal biosensor with an integrated fluid containing structure. Patent Document 3 discloses that a monolithic structure in which a fluid-containing structure and a periodic surface lattice structure of a photonic crystal sensor are integrated includes an optically transparent base layer, a cured polymer layer, and the cured polymer. It describes a thin film made of a relatively high refractive index material deposited on the layer. TiO ₂ or Ti ₂ O ₃ is described as a relatively high refractive index material.

U.S. Patent No. 6,057,031 describes a sensor comprising a nanoporous material having a low refractive index, supported on a bottom surface by a substrate, and coated on the top surface with a high dielectric constant dielectric coating. Patent Document 4 describes tin oxide, tantalum pentoxide, zinc sulfide, titanium dioxide, and silicon nitride as dielectric coating materials.
Patent Documents 3 to 4 do not describe guanidine derivatives.

JP 2014-202574 A International Publication No. 2014/098251 Special table 2010-509590 Special table 2009-520947

The present invention provides, for example, a photonic crystal having high light reflectivity.

That is, the present invention is as follows.
(1) A photonic crystal having a base material layer having convex portions and a surface layer disposed on the surface of the base material layer having convex portions, the surface layer containing a guanidine derivative.
(2) The photonic crystal according to (1), wherein the refractive index of the surface layer is 2.0 or more.
(3) The photonic crystal according to (1) or (2), wherein the light reflectance of the surface layer is 0.2 or more larger than the light reflectance of the base material layer.
(4) The photonic crystal according to one of (1) to (3), wherein the thickness of the surface layer is 1 nm or more.
(5) The photonic crystal according to one of (1) to (4), wherein the refractive index of the base material layer is 1.6 or less.
(6) The photonic crystal according to any one of (1) to (5), wherein the pitch of the convex portions is 100 to 800 nm.
(7) The photonic crystal according to one of (1) to (5), wherein the height of the convex portion is 100 to 800 nm.
(8) An optical sensor comprising the photonic crystal according to one of (1) to (7).
(9) A POCT product comprising the photonic crystal according to one of (1) to (7).
(10) The guanidine derivative is vaporized by heating to form a guanidine derivative on the surface of the base layer of the photonic crystal having a convex portion, and a surface layer containing the guanidine derivative is disposed on the surface of the convex portion of the base layer. A method for producing a photonic crystal.
(11) The method for producing a photonic crystal according to (10), wherein the heating temperature is 300 to 800 ° C.

The photonic crystal of the present invention has, for example, high light reflectivity.

It is an example of embodiment by this invention, and is sectional drawing of a photonic crystal. It is an example of embodiment by this invention, and is sectional drawing of an uneven structure. It is an example of embodiment by this invention, and is an overhead view of an uneven structure. It is an example of embodiment by this invention, and is an overhead view of an uneven structure. It is an example of embodiment by this invention, and is sectional drawing of an uneven structure. It is an example of embodiment by this invention, and is sectional drawing of an uneven structure. It is an example of embodiment by this invention and is an example of the surface layer formation method. It is a figure of the apparatus system of the reflected light measuring apparatus used for this invention. It is an example of embodiment by this invention, and is a graph which shows the angle dependence of light reflectivity among reflected light measurement results.

The photonic crystal of the present invention is a photonic crystal 6 composed of a base material layer 2 having convex portions 3 and a surface layer 1 arranged on the surface of the base material layer 2 having convex portions 3, and has a concavo-convex structure. . The photonic crystal of the present invention is formed by arranging the surface layer 1 at least on the surface of the convex portion 3 of the base material layer 2, for example, by being in close contact therewith. The surface layer 1 is preferably disposed also on the surface of the base material layer 2 in terms of improving the light reflectance.

The photonic crystal of the present invention will be illustrated based on FIG. For example, the photonic crystal 6 of the present invention is composed of a surface layer 1 and a base material layer 2 as shown in FIG. The surface layer 1 is disposed at least on the surface of the convex portion 3 of the base material layer 2. For the sake of explanation, the convex portion 3 is illustrated by filling. The base material layer 2 forms an uneven structure as shown in FIG. By covering the surface of the base material layer 2 with the surface layer 1, the photonic crystal 6 is formed.

The surface layer 1 contains a guanidine derivative. The surface layer 1 is preferably made of a guanidine derivative. In the surface layer 1, the content of the guanidine derivative is preferably 90% by mass or more, more preferably 95% by mass or more, most preferably 98% by mass or more, and even more preferably 99% by mass or more. In the surface layer 1, for example, the content of the guanidine derivative includes not only the guanidine derivative but also the content of a reaction product generated by heating the guanidine derivative.
The content of the guanidine derivative in the surface layer 1 is preferably calculated by measuring X-ray diffraction. X-ray diffraction can be measured by X-ray diffraction measurement described in Patent Document 2, for example.

An example of a method for forming the surface layer 1 in the photonic crystal 6 is shown in FIG. A guanidine derivative 10 is placed in a quartz glass boat 9 and covered with a photonic crystal 6 a having a base material layer 2 and a convex portion 3 to form a surface layer forming set 8. At this time, the surface having the convex portion 3 is covered so as to face the boat 9. This surface layer forming set 8 is heated to a predetermined temperature in a furnace and kept warm for 1 minute. The guanidine derivative is vaporized by heating. The surface layer forming set 8 is cooled and taken out from the furnace, so that the photonic crystal 6 in which the surface layer 1 is formed (for example, attached) to the base material layer 2 is obtained. The heating temperature in the furnace is preferably 300 to 800 ° C., more preferably 380 to 700 ° C., most preferably 500 to 600 ° C., and even more preferably 570 ° C., from the viewpoint of ensuring a refractive index and forming a uniform surface layer. preferable.

Examples of guanidine derivatives include guanidines and guanidine salts that are salts of guanidines. Examples of guanidines include guanidine, nitroguanidine, aminonitroguanidine, aminoguanidine diaminoguanidine, triaminoguanidine and the like. Of the guanidines, guanidine is preferred. Examples of guanidine salts include inorganic acid salts such as hydrochlorides, sulfates, carbonates and nitrates, and organic acid salts such as acetates. Of the guanidine salts, carbonates are preferred. Of the guanidine derivatives, guanidine carbonate is preferred. The guanidine derivative may be commercially available or may be synthesized by a known method.

The refractive index of the surface layer 1 is preferably larger than the refractive index of the base material layer 2 in terms of improving the light reflectance of the photonic crystal. The refractive index of the surface layer 1 is more preferably 2.0 or more. The refractive index of the surface layer 1 is preferably 3.4 or less in that the surface layer 1 can be formed uniformly.
By adjusting the heating temperature in the furnace when the surface layer 1 is formed, the refractive index of the surface layer 1 can be set to a predetermined value.

The thickness 23 of the surface layer 1 is preferably 1 nm or more, more preferably 100 to 1200 nm, most preferably 300 to 1000 nm, and even more preferably 500 to 800 nm. When the thickness 23 of the surface layer 1 is 1 nm or more, the light reflectance is improved. When the thickness 23 of the surface layer 1 is 1000 nm or less, the surface layer 1 can be formed uniformly.

The refractive index of the base material layer 2 is preferably smaller than the refractive index of the surface layer 1 in terms of improving the light reflectance of the photonic crystal. As for the refractive index of the base material layer 2, 1.6 or less are more preferable. The refractive index of the base material layer 2 is preferably 1.0 or more, more preferably 1.3 or more, and most preferably 1.4 or more. *

As the concavo-convex structure of the base material layer 2, as shown in FIG. 3, a structure in which the convex portions 3 are regularly arranged as protrusions in each direction is preferable. As a structure in which the protrusions 3 are regularly arranged as protrusions, a planar lattice is preferable. The planar lattice is preferably one or more of an orthorhombic lattice, a hexagonal lattice, a tetragonal lattice, a rectangular lattice, and a parallel lattice, and more preferably a hexagonal lattice. Of the hexagonal lattice, an equilateral triangular lattice is preferable. The structure in which the protrusions 3 are regularly arranged as protrusions has a larger surface area than the groove-like structure (line and space structure) shown in FIG. 4 and provides higher light reflectivity. FIG. 3 shows a structure in which the convex portions 3 are arranged in an equilateral triangular lattice shape. In FIG. 4, the irregularities are ridges, and the ridges are parallel to each other.

Examples of the method for forming the concavo-convex structure include imprint, laser processing, photolithography and the like. Among these, imprint is preferable. As the imprint, thermal imprint or UV imprint is preferable, and thermal imprint is more preferable. Thermal imprinting is a method for producing a substrate having a fine structure by pressing a mold (mold) having a fine structure against the substrate and transferring the fine structure to a substrate softened by heating. This thermal imprint enables nano-order microfabrication.

The material of the base material layer 2 is preferably glass or resin, more preferably glass. As the glass, at least one of soda lime glass, quartz glass, borosilicate glass, optical glass, and boron-added quartz glass is preferable, and boron-added quartz glass is more preferable. As the resin, one or more of a thermoplastic resin and an ultraviolet curable resin are preferable.

The thickness 21 of the base material layer 2 is preferably 100 μm to 5 mm, more preferably 500 μm to 2 mm. The thickness 21 of the base material layer 2 does not include the height 5 of the convex portion.

The convex portion 3 is preferably made of the same material as the base material layer 2.
As a shape of the convex part 3, a cone and a column are preferable, and a cone is more preferable. As a pyramid, as shown in Drawing 5 (a), it is preferred that the section of convex part 3 is a triangle, and a regular triangle is more preferred. As the cone having a triangular cross section, a cone shape or a pyramid shape is preferable, and a cone shape is more preferable. As a column, as shown in Drawing 5 (b), it is preferred that the section of convex part 3 is a quadrangle, and a square is more preferred. As the column having a quadrangular cross section, a columnar shape or a prismatic shape is preferable. The cross section refers to, for example, a surface cut from the bottom surface in the height direction (the direction of the apex in the case of a cone and the direction of the top surface in the case of a column).

The pitch 4 of the convex portions 3 is preferably 100 to 800 nm, more preferably 150 to 650 nm, and most preferably 200 to 350 nm. When it is 100 nm or more, the light reflectivity is excellent. When it is 800 nm or less, the transparency is excellent.

The pitch 4 of the convex portions 3 is, for example, the dimension between the convex portions 3 adjacent to each other. When the convex portion 3 is a cone, the pitch 4 is a dimension between the apex of the cone and the apex of the cone, as shown in FIG. When the convex part 3 is a column body, the pitch 4 refers to the dimension between the side surface of the column body and the side surface of the column body as shown in FIG. When the convex portion 3 has a groove-like structure, the pitch 4 refers to the dimension between the side surface of the groove-like structure and the side surface of the groove-like structure, as shown in FIG.

The height 5 of the convex portion 3 is preferably 100 to 800 nm, more preferably 150 to 650 nm, and most preferably 200 to 350 nm. When it is 100 nm or more, the light reflectivity is excellent, and when it is 800 nm or less, the transparency is excellent.
The height 5 of the convex portion 3 refers to, for example, the dimension from the bottom surface of the convex portion 3 to the apex or top surface of the convex portion 3.

The aspect ratio of the uneven structure is preferably 10: 1 to 1: 5, more preferably 2: 1 to 1: 2. The aspect ratio means (the height of the convex part 5) / (the width 22 of the convex part). When the aspect ratio is 10: 1 (that is, 10) or less, the contact area between the liquid sample and the flow path is large, and the capillary force increases, so that the liquid sample can be easily moved. When the aspect ratio is 1: 5 (that is, 0.2) or more, it becomes easy to form a concavo-convex structure by imprinting or the like. When the convex portion 3 is a cone, the width 22 of the convex portion may be the diameter 22 of the bottom surface of the cone 3 as shown in FIGS. As shown in FIG. 4 and FIG. 5B, when the convex portion 3 is a column, the width 22 of the convex portion may be the diameter 22 of the bottom side of the column 3.

The method for laminating the surface layer 1 and the base material layer 2 having the convex portions 3 is not particularly limited, but a method for depositing the surface layer, a method for pressure bonding, and a base material having the surface layer 1 and the convex portions 3 are used. Examples thereof include a method of applying an adhesive between the layer 2 and a method by heat sealing.

The present invention may have an adhesive layer 7 between the surface layer 1 and the base material layer 2 having the projections 3 as shown in FIG. Adhesives used for the adhesive layer 7 include rubber adhesives, acrylic adhesives, cross-linked acrylic adhesives, vinyl adhesives, and silicone adhesives. Agents and the like. You may use an ultraviolet absorber, an infrared absorber, etc. for these adhesives as needed.

The photonic crystal 6 of the present invention has high light reflectivity.

The optical sensor to which the photonic crystal 6 of the present invention is applied can recognize, for example, a change in the intensity of reflected light or a change in wavelength caused by a change in the environment on the surface layer 1.

Hereafter, experimental examples are described. The results are shown in Tables 1 to 4.

[shape]
Convex shape: cone, cross section is equilateral triangle

[material]
Guanidine carbonate: Commercially available photonic crystal: Thickness 21 of the base material layer is 1 mm, the convex part 3 is a cone, the cross section of the convex part 3 is a regular triangle, a refractive index of 1.5, an imprint, and a predetermined convex part Boron-added quartz glass having a height of 3 and a predetermined pitch of projections 3 (hereinafter sometimes referred to as glass)

[Evaluation methods]
A method for evaluating physical properties used in the present invention will be described.

Refractive index:
Evaluation was performed using a spectroscopic ellipsometer M-2000DI-T (manufactured by JA Woollam). The refractive index of the surface layer 1 was evaluated. When the base material layer 2 was not covered with the surface layer 1, the refractive index of the base material layer 2 was evaluated.

Light reflectance:
Measurement was performed using the apparatus system shown in FIG. The light source used was a tungsten / halogen light source BPS101 (B & W TEK). The spectroscope used was a multi-channel spectroscope Quest X (manufactured by B & W TEK).
Incident light 14 emitted from the light source 11 was applied to the sample portion 13 at a predetermined incident angle 15. The reflected light 16 reflected from the surface of the sample unit 13 at a predetermined reflection angle 17 was received by the light receiving unit 12. The reflected light 16 passed through light having a wavelength of 550 nm by a spectroscope (not shown), and then the reflected light 16 having a wavelength of 550 nm was received by the light receiving unit 12. The light reflectance at a wavelength of 550 nm was measured.

[Example 1]
A guanidine carbonate 10 (0.5 g) is placed in a boat 9 (2 mL) made of boron-added quartz glass, the height 5 of the convex portions 3 is 270 nm, the pitch 4 of the convex portions 3 is 270 nm, The boat 9 was covered with a boron-added quartz glass (photonic crystal) 6a having the layer 2 and the convex portion 3 (see FIG. 7). The boron-added quartz glass 6a and the boat 9 were heated to 570 ° C. in the furnace and kept for 1 hour, then cooled and taken out from the furnace, whereby the surface layer 1 was formed on the base material layer 2 and the convex part 3. Photonic crystal 6 was obtained. The thickness of the surface layer 1 was 800 nm. The refractive index of the surface layer 1 was 2.0.
The surface layer 1 contained 99% by mass or more of a guanidine derivative.

[Examples 2 to 7]
A surface layer 1 was formed in the same manner as in Example 1. At that time, the height 5 of the protrusions on the glass surface and the pitch 4 of the protrusions were changed from 100 to 800 nm.

[Examples 8 to 11]
A surface layer 1 was formed in the same manner as in Example 1. At that time, the thickness 23 of the surface layer 1 was changed from 100 to 1200 nm.

[Examples 12 to 14]
A surface layer 1 was formed in the same manner as in Example 1. At that time, the refractive index of the surface layer 1 was changed from 2.0 to 3.4 by setting the heating temperature in the furnace to the values shown in Table 4.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that the height 5 of the convex portion was 270 nm, the pitch 4 of the convex portion was 270 nm, and glass having no surface layer was used.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that glass having a surface having no uneven structure (that is, having no convex portion) was used.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that the surface 6 did not have a concavo-convex structure (that is, did not have a convex portion) and glass 6 having no surface layer was used.

[Example 15]
Regarding the photonic crystal of Example 1 and the photonic crystal of Comparative Example 1, the light reflectance was measured when the incident angle and reflection angle were changed from 15 to 55 degrees in steps of 5 degrees. The measurement results are shown in FIG.

When Example 1 and Comparative Example 1 were compared, the light reflectance increased by 24 to 32% by forming the surface layer 1. As in Comparative Example 1 and Comparative Example 3, when the surface layer 1 was not provided, the light reflectance was small. When the surface of the base material layer 2 did not have an uneven structure as in Comparative Example 2 and Comparative Example 3, the light reflectance was small. Referring to FIG. 9, when the incident angle and the reflection angle of light are 40 to 50 degrees, the light reflectance is large.
Comparing Examples 1 to 7, the light reflectance was increased by setting the pitch 4 of the protrusions and the height of the protrusions 3 to 100 to 800 nm.
When Example 1 was compared with Examples 8 to 11, the light reflectance was increased by setting the thickness 23 of the surface layer 1 to an appropriate value.

The photonic crystal of the present invention provides a diffraction grating with high light reflectivity. The photonic crystal of the present invention can be used as a light emitting device such as a laser or a sensor or an optical waveguide. As an optical sensor to which the photonic crystal of the present invention is applied, for example, when applied to a POCT product, the light reflectance and reflected light intensity are improved. That is, the photonic crystal alone does not exhibit light reflectivity that can be applied to POCT, but by increasing the refractive index of the surface layer of the photonic crystal, the light reflectivity and reflected light intensity are increased, and high light reflectivity is achieved. Show. For example, when the light reflectance is increased from 0.1 to 0.3, the intensity of the reflected light is tripled (= 0.3 / 0.1). Will improve. For example, when the light reflectance is larger by 0.2 or more than that of the base material layer alone, the visibility is improved. As a result, the visibility of the POCT product is improved, and high sensitivity and low cost of the POCT product are expected.
Since the present invention uses a guanidine derivative, it has the following advantages. In the present invention, a thin surface layer having a high refractive index can be easily obtained simply by heating the raw material at a low temperature. The present invention does not require special conditions such as vacuum deposition, electron beam deposition, and sputtering. A guanidine derivative is a molecule having carbon and nitrogen as a skeleton, so the surface layer is lightweight and flexible. The present invention is environmentally safe because no metal element is used.

DESCRIPTION OF SYMBOLS 1 Surface layer 2 Base material layer 3 Convex part 4 Convex part pitch 5 Convex part height 6 Photonic crystal having a surface layer 6a Photonic crystal not having a surface layer 7 Adhesive layer 8 Surface layer forming set 9 Boat 10 Guanidine derivative 11 Light source 12 Light receiving part 13 Sample part 14 Incident light 15 Incident angle 16 Reflected light 17 Reflecting angle 21 Thickness 22 Width of convex part 23 Thickness of surface layer

Claims (11)

A photonic crystal having a base layer having a convex portion and a surface layer disposed on the surface of the base layer having a convex portion, the surface layer containing a guanidine derivative. The photonic crystal according to claim 1, wherein the refractive index of the surface layer is 2.0 or more. The photonic crystal according to claim 1 or 2, wherein the light reflectance of the surface layer is 0.2 or more larger than the light reflectance of the base material layer. 4. The photonic crystal according to claim 1, wherein the surface layer has a thickness of 1 nm or more. 5. The photonic crystal according to claim 1, wherein the base layer has a refractive index of 1.6 or less. The photonic crystal according to any one of claims 1 to 5, wherein the pitch of the convex portions is 100 to 800 nm. 6. The photonic crystal according to claim 1, wherein the height of the convex portion is 100 to 800 nm. An optical sensor comprising the photonic crystal according to any one of claims 1 to 7. A POCT product comprising the photonic crystal according to any one of claims 1 to 7. A photonic that vaporizes a guanidine derivative by heating, forms a guanidine derivative on the surface of the base layer of the photonic crystal having a convex portion, and arranges a surface layer containing the guanidine derivative on the surface of the convex portion of the base layer. Crystal production method. The method for producing a photonic crystal according to claim 10, wherein the heating temperature is 300 to 800 ° C.

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