JP7057487B2 - Optical equipment and components - Google Patents

Description

The present invention relates to an optical device using infrared light and an optical member used thereof.

Optical devices using infrared light are used in various applications such as measurement, communication, and biometric authentication, in addition to photography applications such as infrared camera devices.

Such an optical device generally has an infrared light emitting unit and / or an infrared light receiving unit. Further, the optical device has a purpose of reducing unnecessary light such as visible light incident on these light emitting parts and light receiving parts, and for emitting infrared light from these light emitting parts to the outside and emitting infrared light from the outside. An infrared light transmission filter that transmits only infrared light may be provided for the purpose of making the opening of the housing provided for receiving the light to the light receiving unit invisible. Further, in general, an infrared light transmission filter blocks visible light, so that the filter portion is often a dark color such as black.

However, an infrared light transmission filter of a specific color may be desired for the purpose of enhancing the design. For example, when considering an optical device provided as a sensor camera in a mobile terminal or a car, the color of the infrared light transmission filter arranged in the opening so that the opening for the infrared sensor provided in the housing is not conspicuous. There is a desire to match the taste with the housing color (body color). Since there are various body colors for mobile terminals and cars, an infrared light transmission filter that can easily realize various colors is desired.

As an infrared light transmission filter other than a dark color, for example, there is a white infrared light transmission filter described in Patent Documents 1 and 2. The infrared light transmission filter described in Patent Document 1 realizes a white infrared light transmission filter by providing a semi-transparent diffuser and a mirror that transmits infrared light and reflects visible light. are doing.

Further, the infrared transmittance filter described in Patent Document 2 uniformly disperses fine particles having a refractive index different from that of the binder in a transparent binder to increase the transmittance in the infrared region and in the visible region. A white infrared transmission filter is realized by increasing the scattering.

Further, Patent Documents 3 and 4 describe examples of infrared light transmission filters that realize colors other than white. The infrared light transmission filter described in Patent Document 3 reflects visible light and scatters visible light on the first side (visual recognition side) of the dielectric multilayer film that transmits infrared light. By providing a portion (uneven surface, cholesteric phase liquid crystal layer, etc.), not only the visible light is blocked while transmitting infrared light, but also the visible light is reflected and scattered, so that it is viewed from the first side. It realizes an infrared transmission filter in which the light receiving region of visible light is observed as if it is colored in a color other than black (for example, white, green, orange, etc.).

Further, the infrared light transmission filter described in Patent Document 4 is provided with a dielectric multilayer film that transmits infrared light and reflects and transmits visible light on one surface of the substrate, and the dielectric is provided. Any appearance color is realized by the visible light reflected from the multilayer film. Further, in Patent Document 4, one surface of the base material is processed into a satin finish, and a dielectric multilayer film is provided on the surface to give a scattering component to the reflected light to give a pearly texture to the appearance color. A configuration for imparting (improving the color development of the reflected color) and a configuration for providing an infrared transmissive black printing layer 91 that transmits infrared light and blocks the transmission of visible light on the inner surface side of the device of the dielectric multilayer film are also described. Has been done.

Further, in Patent Document 5, in order to prevent the background from being seen, an infrared ray having a structure in which a color material layer that absorbs a part of visible light and transmits infrared light is provided on the mirror coat layer. A light transmission filter is described.

Japanese Unexamined Patent Publication No. 2014-71295 Japanese Unexamined Patent Publication No. 2010-72616 International Publication 2016/11452 Japanese Patent No. 4212010 Japanese Patent No. 4627610

However, the methods described in Patent Documents 1 and 2 have a problem that the sensitivity of the transmission / reception portion of infrared light is lowered when trying to improve the scattering property of visible light in order to improve the design. Specifically, in the methods described in Patent Document 1 and Patent Document 2, even if the transmittance for infrared light can be increased, the scattering ability also works for infrared light, so that infrared light is used. There is a problem that the haze cannot be reduced. In other words, there is a problem that the straight transmittance of infrared light is not sufficient.

When the amount of light traveling straight ahead is smaller than the amount of incident infrared light, a large amount of loss due to reflection, absorption, and scattering is generated. In such a case, for example, when combined with a light receiving element such as an infrared camera, the image may become dark or the image may be blurred, resulting in a decrease in resolution, and the problem that the desired sensitivity and characteristics of the device cannot be obtained. There is.

According to the method described in Patent Document 3, it is possible to realize an infrared transmission filter having high reflection and scattering property of visible light while sufficiently maintaining the linear transmittance of infrared light. However, if it is attempted to realize various colors only by the reflected light of the dielectric multilayer film, it is not easy because the dielectric multilayer film must be redesigned for each color. In addition, it is necessary to take measures to prevent transmission of visible light in a wavelength region where the reflection and scattering property is low.

The methods described in Patent Documents 4 and 5 also have the same problems as those in Patent Document 3 in that the color taste is realized only by the reflected light of the dielectric multilayer film. Further, when visually recognizing the specular reflection color of the dielectric multilayer film, there arises a problem that the tint varies depending on the viewing angle. In Patent Document 4, in order to improve the filter characteristics (that is, to make the background invisible), infrared transmission that prevents visible light from being transmitted to the back surface side of the dielectric multilayer film when viewed from the incident side of visible light. Although the configuration in which the black printing layer 91 is provided is described, it is only for the purpose of imparting a texture and improving color development, and the color reproduction range does not change accordingly. The same applies to the color material layer described in Patent Document 5.

In view of the above problems, it is an object of the present invention to provide an optical device having a wide color reproduction range and an optical member for that purpose without complicated design while maintaining designability and high straight-line transparency to infrared light. And. Another object of the present invention is to provide an optical member having a simple design, having high reflection and scattering property only for light having a specific wavelength that expresses a desired color among visible light, and having high straight-line transmission of infrared light. And.

The optical member according to the present invention reflects and scatters light of a specific wavelength corresponding to a specific color, which is light in at least a part of the wavelength band in the visible region, absorbs light other than the specific wavelength, and is in the infrared region. It is provided with an absorption / reflection / scattering unit that transmits light in at least a part of the wavelength band, has a straight-line transmission rate of 75% or more for light in at least a part of the wavelength band in the infrared region, and when visible light is incident, the specific Observed to be colored in color, the absorption / reflection / scattering unit has a selective reflection unit that reflects light in the visible region and transmits light in at least a part of the wavelength band in the infrared region, and the visible region. A scattering unit that scatters light and a specific visible light absorbing unit that absorbs light other than the specific wavelength in the visible region are included. However, when viewed from the first side, which is the incident side or the emission side of the infrared light and the predetermined side of the side on which the visible light is incident, the specific visible light absorption unit, the scattering unit, and the selective reflection unit. The feature is that they are provided in the order of .

Further, the optical device according to the present invention has a light emitting unit that emits light in a part of the wavelength band in the infrared region, or a light receiving unit that receives light in a part of the wavelength band in the infrared region, and the light emitting unit or the light receiving unit. A housing that surrounds the portion and an infrared light transmission filter provided in the opening of the housing are provided, and the infrared light transmission filter is characterized by being the above-mentioned optical member.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an optical member having high reflection scattering property and high straight-line transmission of infrared light only for light having a specific wavelength that expresses a desired color among visible light with a simple design. Further, according to the present invention, it is possible to provide an optical device having a wide color reproduction range without complicated design while maintaining designability and high straight-line transparency to infrared light.

It is a block diagram which shows the example of the optical member of 1st Embodiment. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is explanatory drawing which shows the example of the concavo-convex structure 342. It is explanatory drawing which shows the relationship between the inclination angle of the concave-convex surface of a selective reflection film 33, and the reflection scattering of visible light. It is a graph which shows the example of the angle dependence of the light amount distribution of the transmission component of infrared light by a reflection scattering part 31. It is explanatory drawing which shows the example of the manufacturing method of the optical member 30. It is explanatory drawing which shows the other example of the manufacturing method of the optical member 30. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the other example of an optical member. It is a graph which shows the example of the wavelength dependence of the phase term coefficient in a diffraction structure 22. It is a graph which shows the example of the angle dependence of the light amount distribution of the transmission component of infrared light by a diffraction structure 22. It is a block diagram which shows the other example of an optical member. It is a block diagram which shows the example of the optical apparatus of 2nd Embodiment. It is a graph which shows the transmittance characteristic of 3 kinds of colored resin materials. It is a graph which shows the transmittance characteristic of a multilayer film as a selective reflection part. It is a graph which shows the measurement result of the transmitted light amount of the optical member of an Example.

Embodiment 1.
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of an optical member 10 according to a first embodiment of the present invention. The optical member 10 shown in FIG. 1 exhibits a specific color to the observer in an optical device or the like using infrared light, blocks visible light from the inside of the device, and emits infrared light. It is used as an infrared light transmission filter that transmits light. The optical member 10 reflects and scatters only the light having a specific wavelength among the visible light while transmitting the infrared light, so that the light receiving region of the visible light is predetermined at least when viewed from the first side defined as the visual viewing side. It is observed as if it was colored in the color of. The observed color is not limited to a single color, and includes, for example, a combination of a plurality of colors different for each region such as a mottled pattern or a camouflage. Here, the first side is the incident side or the emitting side of the infrared light in the optical member 10, and is one of the predetermined sides on which the visible light is incident. Further, in the present invention, the other side other than the first side is referred to as a second side. In the following, the first side may be simply referred to as a visible side and the second side may be simply referred to as an anti-visual side, but the surface on which the desired color is observed (hereinafter, simply referred to as an observation surface) is the first. It is not limited to the side of 1. For example, the second side can also be an observation surface.

The optical member 10 shown in FIG. 1 includes a base material 14, a selective reflection unit 13, a scattering unit 12, and a specific visible light absorption unit 15.

The base material 14 may be made of a member having transparency to infrared light. The base material 14 may be, for example, a substrate made of glass, resin, or the like. Further, when the optical member 10 is provided in a car or the like, the base material 14 may be a resin substrate having impact resistance in order to prevent cracking due to an impact such as stone jumping.

The selective reflection unit 13 has a function of reflecting visible light at a certain ratio or more and transmitting infrared light at a certain ratio or more. Examples of the selective reflection unit 13 include a dichroic mirror, a cholesteric phase liquid crystal film, and the like. More specifically, if the selective reflection unit 13 has a reflective member such as a dielectric multilayer film used for a mirror layer of a dichroic mirror or a cholesteric phase liquid crystal layer used for a cholesteric phase liquid crystal film. good.

The scattering unit 12 has a function of exhibiting a scattering ability with respect to visible light. The scattering unit 12 preferably has a function of exhibiting a higher scattering ability than infrared light with respect to visible light. Examples of the realization of the function of exhibiting such a scattering ability include an uneven surface provided at an arbitrary medium interface (particularly a reflective member), a fine particle-containing resin layer which is a layer formed by a resin containing fine particles, and diffraction. The structure and the like can be mentioned.

For example, when the scattering portion 12 is an uneven surface formed at an arbitrary medium interface, visible light can be scattered by utilizing the reflection and refraction phenomena on the uneven surface. In particular, when the scattering portion 12 is an uneven surface provided on the reflecting member, the amount of deflection of the light beam is larger in the reflection than in the refraction or the like, so that the scattering of visible light can be increased. Further, for example, when the scattering unit 12 has a diffraction structure, visible light can be scattered by utilizing the diffraction phenomenon in the diffraction structure. Further, for example, when the scattering unit 12 is a fine particle-containing resin layer, visible light can be scattered mainly by utilizing the refraction phenomenon at the interface with the fine particles in the resin layer which is a binder.

In the present invention, visible light may be light having a wavelength of 400 nm to 750 nm. Further, the infrared light may be light having a wavelength of 800 nm or more. If the visible range (color) to be reflected and scattered, the detection band of the infrared sensor, etc. are determined, the target wavelength band is further limited within the above range for both visible light and infrared light. May be good. However, with respect to visible light, the tint can be adjusted by the specific visible light absorbing unit 15 described later without particularly limiting the target wavelength band. Hereinafter, when the description is made without particular limitation, the visible region has a wavelength of 400 nm to 780 nm, the infrared region has a wavelength of 780 nm to 2000 nm, which is regarded as a near infrared region, and particularly has a wavelength of 800 nm to 1000 nm. It is light, and infrared light is assumed to be light in the infrared region.

In FIG. 1, it is shown that the selective reflection unit 13 and the scattering unit 12 are composed of different members and are in contact with each other. For example, a part of the members constituting the selective reflection unit 13 is a scattering unit. 12 (for example, an uneven surface, a diffraction structure, etc.) may be configured. That is, the selective reflection unit 13 and the scattering unit 12 may be integrally formed of, for example, the same member. Further, another functional layer may be provided between the selective reflection unit 13 and the scattering unit 12, and these may not be in contact with each other.

When the selective reflection unit 13 and the scattering unit 12 are not in contact with each other, it is preferable that the distance between the selective reflection unit 13 and the scattering unit 12 is short. In particular, when the scattering portion 12 is realized by a diffraction structure, the distance is preferably 3 μm or less. If the distance between the two is too large, the coefficient of the phase term of the reflected light of visible light deviates from 2Δnd / λ, which will be described later, which is not preferable.

In the present embodiment, the scattering unit 12 may be provided on the visual recognition side (at least the first side) of the selective reflection unit 13. Further, the specific visible light absorption unit 15 may be provided on the visual recognition side of the scattering unit 12. That is, the selective reflection unit 13, the scattering unit 12, and the specific visible light absorption unit 15 may be provided in the order of the specific visible light absorption unit 15, the scattering unit 12, and the selective reflection unit 13 when viewed from the visual recognition side.

The specific visible light absorption unit 15 is a part of the incident visible light, and the light absorption rate of a specific wavelength for humans to recognize a desired color is lower than the light absorption rate of other wavelength ranges. ..

The specific visible light absorption unit 15 may be, for example, a colored resin material containing a colored material in the resin material. Examples of the resin material include thermoplastic resins such as polycarbonate (PC) and cycloolefin (COP), and thermosetting resins such as polyimide (PI), polyetherimide (PEI), polyamide (PA), and polyamideimide (PAI). , Energy ray curable resins such as acrylic and epoxy can be used.

When a thermosetting resin or an energy ray-curable resin is used, a coloring material may be added at the stage of a polymerization precursor compound (hereinafter, also referred to as a polymerizable compound) such as an oligomer or a monomer, and then cured. Among these, an energy ray curable resin that does not substantially contain a solvent is preferably used from the viewpoint of moldability. By using the energy ray-curing resin, it is possible to cover the cover base material and cure it, so that the flatness of the surface of the colored resin material can be increased.

Examples of the energy ray-curable resin include ultraviolet-curable resins that are cured by irradiating with ultraviolet rays. As such a polymerizable compound, any component that can be cured by a polymerization reaction to become a cured product can be used without particular limitation. For example, a radical polymerization type curable resin, a cationic polymerization type curable resin, and a radical polymerization type curable compound (monomer) can be used without particular limitation. Among these, a radical polymerization type curable compound (monomer) is preferable from the viewpoint of polymerization rate and moldability described later. Examples of the radical polymerization type curable resin include carbon-carbon unsaturated doubles such as (meth) acryloyloxy group, (meth) acryloylamino group, (meth) acryloyl group, allyloxy group, allyl group, vinyl group and vinyloxy group. Examples thereof include a resin having a group having a bond.

When performing UV curing, it is preferable to use a photopolymerization initiator, for example, light appropriately selected from acetophenones, benzophenones, benzoins, benzyls, benzoin alkyl ethers, benzyl dimethyl ketals, thioxanthones and the like. A polymerization initiator is preferably used. The photopolymerization initiator may be used alone or in combination of two or more. The amount of the photopolymerization initiator is preferably 0.01% by mass to 5% by mass, particularly preferably 0.1% by mass to 2% by mass, based on the total amount of the polymerizable composition. In the present embodiment, the polymerizable compound is not particularly limited, but is ethoxylated o-phenylphenol acrylate, 2- (perfluorohexyl) ethyl methacrylate, cyclohexyl (meth) acrylate, and isobonyl (meth). Acrylate, tricyclodecane (meth) acrylate, tricyclodecanemethanol (meth) acrylate, tricyclodecaneethanol (meth) acrylate, 1-adamantyl acrylate, 1-adamantyl methanol acrylate, 1-adamantyl ethanol acrylate, 2-methyl-2 Monofunctional compounds such as -adamantyl acrylate, 2-ethyl-2-adamantyl acrylate, 2-propyl-2-adamantyl acrylate, dicyclopentanyl acrylate, and 9,9-bis [4- (2-acryloyloxyethoxy) phenyl. ] Fluolene, diethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, isobonyldi (meth) acrylate, tri Bifunctional such as cyclodecane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, tricyclodecane diethanol di (meth) acrylate, adamantan diacrylate, adamantan dimethanol diacrylate, tricyclodecane dimethanol diacrylate. Examples include compounds, trifunctional compounds such as trimethylolpropanetri (meth) acrylate, tetrafunctional compounds such as pentaerythritol tetra (meth) acrylate, and hexafunctional compounds such as dipentaerythritol hexa (meth) acrylate. Be done.

The polymerizable compound may contain one kind or two or more kinds. When only a monofunctional compound is used, it may cause cohesive failure at the time of mold release after molding, so it is preferable to contain a polyfunctional compound having two or more functionalities. The polyfunctional compound in the polymerizable compound set is preferably 1% by weight or more and 90% by weight or less, and more preferably 10% by weight or more and 80% by weight or less. If the amount of the polyfunctional compound is less than 1% by weight, the effect of improving aggregation fracture is insufficient, and if it exceeds 90% by weight, shrinkage after polymerization may become a big problem.

Further, in addition to the above-mentioned functional group having a carbon-carbon unsaturated double bond, a polymerizable compound that causes a ring-opening reaction such as an epoxy group can also be used. Since such a compound has a small polymerization shrinkage, not only can precision molding be possible with a molding die, but also warpage can be reduced. Although not particularly exemplified, even in this case as well, it is preferable to contain a polyfunctional compound having a bifunctionality or higher because the monofunctional compound alone may cause aggregation failure at the time of mold release after molding. The polyfunctional compound in the polymerizable compound set is preferably 1% by weight or more and 90% by weight or less, and more preferably 10% by weight or more and 80% by weight or less.

The coloring material may be a dye dissolved in the above-mentioned resin material, or may be an organic pigment dispersed in the resin material. It can be appropriately selected according to the requirements such as durability and glossiness.

As the organic pigment, the pigment described in Reference 1 (Jiro Aihara, supervised by Okura Lab., "Technology and application development of functional pigments", CMC Publishing Co., Ltd., September 2004, p.246) should be used as appropriate. Can be done. At that time, a plurality of pigments can be added to the resin material for the purpose of adjusting the observed color.

Here, coloring materials are exemplified for the three colors of red, green, and blue.

As the red coloring material, coloring materials such as anthracene-based, diketopyrrolopyrrole-based, quinacridone-based, azo (bisazo) -based, xanthene-based, perylene-based, and anthraquinone-based can be used.

Examples of the diketopyrrolopyrrole system include pigment red 254, pigment red 255, pigment red 256, pigment red 270, pigment red 272, pigment orange 71, and pigment orange 73. Examples of the quinacridone system include pigment red 122, pigment red 202, pigment red 206, pigment red 207, pigment red 209, pigment orange 48, and pigment orange 49. Pigment red 17, pigment red 21, pigment red 22, pigment red 23, pigment red 31, pigment red 32, pigment red 37, pigment red 38, pigment red 60, pigment red 112, pigment red 114, pigment red 144, pigment red 146, pigment red 150, pigment red 166, pigment red 187, pigment red 188, pigment red 214, pigment red 220, pigment red 221, pigment red 253, pigment red 266, pigment red 268, Pigment red 269 and so on. Examples of the xanthene type include pigment red 81 and pigment red 169. Examples of the perylene system include pigment red 123, pigment red 149, pigment red 178, pigment red 179, pigment red 190, pigment red 224, and pigment red 242. Examples of the anthraquinone system include pigment red 168, pigment red 177, and pigment red 216.

As the green coloring material, phthalocyanine-based, naphthoquinone-based, anthracene-based, triarylmethane-based, and the like can be used. Further, a green color may be obtained by blending a yellow coloring material and a blue coloring material.

Examples of phthalocyanines include pigment green 7, pigment green 36, and pigment green 58. Examples of the naphthoquinone system include pigment green 8. Examples of the anthracene system include pigment green 47 and pigment green 54. Examples of the triarylmethane system include pigment green 1 and pigment green 4.

Examples of the blue coloring material include triarylmethane-based, phthalocyanine-based, and anthraquinone-based.

Examples of the triarylmethane system include pigment blue 1, pigment blue 9, pigment blue 24, pigment blue 56, and pigment blue 61. Examples of the phthalocyanine system include pigment blue 15 and pigment blue 16. Examples of anthraquinone systems include pigment blue 60.

The pigment preferably has a particle size of a certain size or less in order to suppress scattering of the specific visible light absorber 15 with respect to infrared light. According to Reference 2 (Bruce M. Novak, "Hybrid Nanocomposite Materials --Between Inorganic Glasses and Organic Polymers", Advanced materials, vol.5 Issue.6, 1993, p.422), the body integral index of the pigment is Vp [%]. ], When the optical path length is χ [nm], the pigment radius is r [nm], the wavelength is λ [nm], the refractive index of the pigment is _{n p} , and the refractive index of the resin material is nm, the transmittance (I). / _IO ) is expressed by the following equation (1).

According to the formula (1), for example, assuming Vp = 5%, χ = 10000 nm, λ = 940 nm, n _p = 1.7, _nm = 1.52, the particle size of the pigment (twice the radius). The relationship of transmittance is shown in Table 1 below.

Therefore, in order to obtain the optical member 10 having no unnecessary scattering, the particle size of the pigment is preferably 500 nm or less, more preferably 400 nm or less. The particle size of particles such as pigments can be measured by a laser diffraction / scattering type particle size distribution measuring device. The particle size referred to here is the median diameter.

The film thickness of the colored resin material forming the specific visible light absorbing portion 15 is not particularly limited, but when the scattering portion 12 is realized by the uneven surface, it is assumed that the sag of the uneven surface is 3 to 20 μm, and the film thickness is the same. Is preferably 10 to 50 μm. This is because when the colored resin material is thinner than 10 μm, the thickness of the colored resin material on the convex portion becomes thin, which may cause color unevenness. Further, when the colored resin material is thicker than 50 μm, unnecessary absorption or scattering may occur in the infrared region, which is not preferable.

The ratio (content rate) of the coloring material in the resin material depends on the size of absorption per weight of the coloring material to be added and the thickness of the resin material serving as a binder, but is usually 1% by weight to 20% by weight. If it is less than 1% by weight, the desired color is not developed, which is not preferable. If it is more than 20% by weight, the refractive index of the colored resin material is affected by the refractive index of the colored material itself. As a result, for example, a difference in refractive index may occur between the specific visible light absorber 15 and the base material 14, and the straight-line transmittance of infrared light may decrease, which is not preferable.

Hereinafter, the scattering unit 12, the selective reflection unit 13, and the specific visible light absorption unit 15 may be collectively referred to as an absorption / reflection scattering unit 11. In this case, the absorption / reflection / scattering unit 11 reflects and scatters the light of a specific wavelength in the visible light by a certain ratio or more, and absorbs the light other than the specific wavelength in the visible light by a certain ratio or more and more than the light of the specific wavelength. Moreover, it has a function of transmitting infrared light in a straight line at a certain ratio or more.

In the example shown in FIG. 1, the visible light 102 is incident on the optical member 10 in the + z direction from the first side of the optical member 10. On the other hand, the infrared light may be incident on the optical member 10 in the + z direction from the first side of the optical member 10 or may be incident on the optical member 10 in the −z direction from the second side. Infrared light 101a in the figure is an example of the former, and infrared light 101b is an example of the latter.

For example, when visible light 102 is incident on the optical member 10, a part of the visible light 102 is absorbed by the specific visible light absorbing unit 15, and the remaining light is reflected and scattered by the scattering unit 12 and the selective reflecting unit 13. At this time, most of the components of the visible light 102 other than the wavelength set as the absorption band of the specific visible light absorption unit 15 (light of the above-mentioned specific wavelength) are not absorbed by the specific visible light absorption unit 15. , Is reflected and scattered by the scattering unit 12 and the selective reflecting unit 13. On the other hand, among the visible light 102, the light having the wavelength defined as the absorption band of the specific visible light absorption unit 15 is absorbed by the specific visible light absorption unit 15 twice, when it is incident and after it is reflected. .. Therefore, when viewed from at least the first side, the optical member 10 appears to be colored in a specific color according to the absorption characteristics of the specific visible light absorption unit 15. The arrow 1021 in FIG. 1 represents the light of a specific wavelength that is reflected and scattered without being absorbed by the specific visible light absorbing unit 15 among the incident visible light 102.

Further, when the infrared light 101a is incident on the optical member 10, the infrared light 101a is partially absorbed by the specific visible light absorbing unit 15 or partially scattered by the scattering unit 12, but many components are transmitted straight ahead. Then, it passes through the selective reflection unit 13 as it is. Further, when the infrared light 101b is incident on the optical member 10, the infrared light 101b is transmitted through the selective reflection unit 13 and then partially scattered by the scattering unit 12 or partially absorbed by the specific visible light absorbing unit 15. However, many components pass straight through the scattering unit 12.

As described above, most of the visible light 102 having a wavelength other than the specific wavelength is absorbed by the specific visible light absorption unit 15, and the light 1021 having the specific wavelength of the visible light 102 is the specific visible light absorption unit 15 and the scattering unit. It passes through 12 and is reflected by the selective reflection unit 13. At this time, the light 1021 having a specific wavelength may pass through the scattering unit 12 twice, whereas the infrared light 101a and the infrared light 101b pass through the scattering unit 12 only once. Therefore, the optical member 10 absorbs light other than the specific wavelength of the visible light 102, and has a specific wavelength emitted as reflected light of the visible light 102 as compared with the infrared light 101a and the infrared light 101b. Scattering with respect to light 1021 can be increased. Further, when the uneven surface of the selective reflection unit 13 is used as the scattering unit 12 as described later, a large scattering can be obtained by using the uneven surface. This agrees that the scattering with respect to the infrared light 101a and the infrared light 101b can be reduced as compared with the visible light 102 (particularly, the light 1021 having a specific wavelength). Therefore, the optical member 10 can absorb light other than the specific wavelength of the visible light 102, scatter and reflect the light 1021 of the specific wavelength, and transmit more infrared light 101a and infrared light 101b in a straight line. can.

As shown in FIG. 2A, the optical member 10 may have a structure in which the absorption / reflection scattering portion 11 is sandwiched between two base materials 14 (base materials 14a and 14b). Further, as shown in FIG. 2B, when visible light is incident from the second side (-z direction in the figure), the scattering portions 12 (scattering portions 12a, 12b) may be provided, and specific visible light absorbing units 15 (specific visible light absorbing units 15a and 15b) may be provided on the outside thereof, respectively. In such a case, assuming that both the first side and the second side are the visual recognition side, the specific visible light absorption unit 15, the scattering unit 12, and the selection are selected when viewed from the first side and the second side, respectively. The reflecting portions 13 may be provided in this order. At this time, the specific visible light absorption unit 15 may take the place of the base material 14.

Hereinafter, some more specific configuration examples of the optical member 10 will be described.

First, an example of realizing the scattering unit 12 by utilizing the uneven surface of the selective reflection unit 13 will be described. FIG. 3A is a schematic cross-sectional view showing a configuration example of an optical member 30 that realizes the scattering portion 12 by utilizing the uneven surface of the selective reflection portion. Further, FIG. 3B is an exploded cross-sectional view of a main part of the optical member 30 shown in FIG. 3A. The optical member 30 shown in FIG. 3 includes a base material 34, a selective reflection film 33, and a colored resin material layer 35. An uneven surface 331 is formed on at least the first side of the selective reflection film 33 of this example. Further, the two members in contact with the selective reflective film 33, that is, the surfaces of the base material 34 and the colored resin material layer 35 on the selective reflective film 33 side are also formed with uneven surfaces 351 and 341 having shapes that are substantially fitted to each other. ..

In this example, the selective reflection film 33 corresponds to the selective reflection unit 13. Further, the uneven surface 331 of the selective reflection film 33 corresponds to the scattering portion 12. Further, the colored resin material layer 35 corresponds to the specific visible light absorption unit 15. In this example, the selective reflection film 33 having the uneven surface 331 and the colored resin material layer 35 are collectively referred to as an absorption / reflection scattering unit 31. Further, a member that is in contact with the uneven surface 331 of the selective reflection film 33 and has a flat surface on the opposite side is also referred to as an uneven filling member. In the example shown in FIG. 3, the base material 34 and the colored resin material layer 35 correspond to the uneven filling member.

The selective reflection film 33 may be configured to reflect visible light at a certain ratio or more and transmit infrared light at a certain ratio or more. Examples of the selective reflection film 33 include a dielectric multilayer film and a cholesteric phase liquid crystal film.

The concavo-convex surface 331 of the selective reflective film 33 is, for example, a selective reflective film 33 (dielectric multilayer film or the like) having a substantially uniform film thickness h on the concavo-convex surface 341 obtained by forming the concavo-convex structure 342 on the surface of the base material 34. ) Is formed (laminated). That is, the uneven surface 331 may be formed following the uneven surface 341 of the base material 34.

Further, in this example, a colored resin material layer 35 having a substantially flat facing surface (viewing side surface) is provided on the uneven surface 331 of the selective reflection film 33. Further, on the surface of the colored resin material layer 35 on the side of the selective reflection film 33, an uneven structure 352 having a shape that fits with the uneven surface 331 of the selective reflection film 33 (furthermore, the uneven surface 341 of the base material 34) is formed. (See the shaded area in FIG. 3 (b)). The concavo-convex structure 352 of such a colored resin material layer 35 can be formed, for example, by filling the recesses of the concavo-convex surface 331 of the selective reflection film 33 with the colored resin material which is the material of the colored resin material layer 35.

Here, as the laminated state of the base material 34, the selective reflective film 33, and the colored resin material layer 35, they may be arranged close to each other without any gaps. Specifically, not only when they are in direct contact with each other, but also indirect contact, for example, including an adhesive layer having a film thickness of several tens of μm or less (within 100 μm) or a thin film acting as another functional layer. Including the case where it is. The function of the thin film is not particularly limited. Hereinafter, the term “contacting” may be simply used, including the case where the total film thickness is within 100 μm and is indirectly in contact with each other.

The base material 34 is the same as the base material 14 described above. Further, the colored resin material layer 35 may have the function of the specific visible light absorbing unit 14 described above. That is, the colored resin material layer 35 has high transparency to infrared light, and the light absorption rate of a specific wavelength for humans to recognize a desired color is higher than the light absorption rate of other wavelength ranges. It suffices to have a function (absorption band) that lowers the light absorption coefficient, that is, wavelength dependence of the light absorption coefficient. The absorption band wavelength of the colored resin material layer 35 can be appropriately adjusted with a pigment or the like to be contained.

In the example shown in FIG. 3, the base material 34 and the colored resin material layer 35 have substantially the same refractive index at least in the target wavelength band in the infrared region. Here, in a state where the refractive indexes are substantially the same, the difference in refractive index between the two materials in the target wavelength band or the average value thereof is preferably 0.05 or less, more preferably 0.03 or less, and further preferably 0.01 or less. It is preferably 0.005 or less, and particularly preferably 0.005 or less. At this time, the average refractive index may be used as the refractive index of the colored resin material layer, or the refractive index of the resin material used for the colored resin material layer may be used. Hereinafter, the same applies to the consistency of the refractive index as described above.

With such a configuration, a large reflection scattering can be exhibited with respect to the light 1021 having a specific wavelength among the visible light 102 by utilizing the inclined reflection surface (concave and convex surface 331) of the selective reflection film 33, and the visible light 102 can be exhibited. Among them, since it is possible to exhibit higher absorption than the light 1021 having a specific wavelength for light other than the specific wavelength, it is possible to obtain a design property and a high shielding property to the inside. Further, since the refractive indexes of the members (base material 34 and the colored resin material layer 35) on both sides of the selective reflection film 33 having the uneven surface 331 are substantially the same with respect to the infrared light 101a and the infrared light 101b. It is possible to prevent refraction caused by the uneven structure portion of the member, and as a result, high straight-line transparency can be obtained. This is because this configuration does not cause a difference in optical path length due to a difference in position within the incident aperture with respect to infrared light, or even if it does occur, it is suppressed to a small value.

As shown in FIGS. 4A and 4B, when the second side of the optical member 30 is also used as an observation surface, the optical member 30 is used in addition to or in place of the base material 34. The colored resin material layer 35 (colored resin material layer 35b) of 2 may be provided. Even in such a case, a substantially uniform film thickness h is formed on the uneven surface 351b obtained by forming the uneven structure 352b on the surface of one of the colored resin material layers 35 (for example, the colored resin material layer 35b). By forming (laminating) a selective reflection film 33 (dielectric multilayer film, etc.), it is incident from the second side at the same time as the uneven surface 331a that acts as a scattering part for visible light 102a incident from the first side. An uneven surface 331b that acts as a scattering portion for visible light 102b is obtained.

In the case of this example, the colored resin material layer 35a and the colored resin material layer 35b, which are the members (concavo-convex filling member) on both sides of the selective reflection film 33, have substantially the same refractive index at least in the target wavelength band in the infrared region. You just have to do it. By doing so, even if the selective reflective film 33 has an uneven surface, the uneven structures 352a and 352b having a shape that fits each other on both sides thereof are arranged. The difference in optical path length due to the difference in the position within the incident aperture generated in the colored resin material layer 35 on the incident side can be absorbed by the colored resin material layer 35 on the exit side. Therefore, a high straight transmittance can be obtained for infrared light 101a and 101b.

Although FIG. 4 shows a configuration including the base materials 34a and 34b, the base materials 34a and 34b may be omitted. Further, even when only one side is used as the observation surface, the second base material 34b may be laminated on the colored resin material layer 35 (see FIG. 5A). At this time, as shown in FIG. 5B, it is also possible to change the stacking order of the second base material 34b and the colored resin material layer 35. In the configuration shown in FIG. 5B, an uneven structure is formed on the surface of the two base materials 34a and 34b arranged on both sides of the selective reflection film 33 on the side in contact with the selective reflection film 33. In this case, the base material 34a may be included and may be referred to as an absorption / reflection / scattering unit 31, and the colored resin material layer 35 at this time may have a flat plate shape in which the main surfaces facing each other are flat.

The uneven surface of the uneven surface 331 (or the uneven surface of the base material 34 or the colored resin material layer 35 as the base thereof) as the scattering portion of this example is an uneven shape such as a rough surface formed by sandblasting or the like. However, a shape having many smooth curved surfaces (including free curved surfaces, aspherical surfaces, and spherical surfaces) is more preferable. In general, a rough surface formed by sandblasting or the like has a shape in which the derivative has many discontinuous points. For example, when considering forming a dielectric multilayer film as a selective reflection film 33 on such a rough surface, This is because the multilayer film cannot be formed into a film with a uniform thickness and may not have desired characteristics.

Examples of the concave-convex structure that forms such a smooth curved surface include a lens array in which a large number of minute spherical or aspherical lenses are arranged, a prism array in which a large number of prisms are arranged, and the like. The lens or prism in the array is not limited to one type and may be a plurality of types, and these may be arranged regularly or irregularly. Further, as another example, an uneven portion of a frost plate whose surface is smoothed by etching the rough surface of a base material formed by sandblasting or the like with hydrofluoric acid, or a diffusion element such as such a frost plate. Examples thereof include the uneven portion of the resin layer formed by transferring the uneven portion to the resin layer of the base material.

Further, when a dielectric multilayer film is formed as the selective reflection film 33, the thickness of the multilayer film may be several μm. Therefore, when the dielectric multilayer film is formed on the uneven surface of the base material 34 or the colored resin material layer 35, the width of each concave portion constituting the uneven surface (the concave portion passes through the bottom of the concave portion). If (the length of the straight line connecting the end points in the plane direction) w is too small, it may not be possible to form a film with a desired thickness. Therefore, in the uneven surface of the base material 34 or the colored resin material layer 35 in contact with the selective reflective film 33, the region where the width w of the recess is less than 5 μm is preferably less than 10% of the entire effective region where visible light is incident. It is more preferable that the width w of all the recesses in the effective region is 5 μm or more. When the uneven surface includes a convex portion, it is more preferable that the convex portion also satisfies the above conditions. That is, it is more preferable that the region where the width w of the convex portion is less than 5 μm is less than 10% of the entire effective region on which visible light is incident, and further when the width w of all the convex portions in the effective region is 5 μm or more. preferable. As for the width w of the convex portion, the bottom portion of the concave portion in the description of the width w of the concave portion may be read as the top portion of the convex portion.

In addition, when the explanation is given without particular mention, the concave portion constituting the concave-convex surface is a region including the concave apex but not the convex apex or including the convex apex as a boundary portion, and particularly a region surrounded by the convex ridge line. Is. Further, the convex portion is a region including a convex apex but not a concave apex or including a concave apex as a boundary portion, and is particularly a region surrounded by a concave ridge line. In the case of the bottom of the concave portion, not only the concave apex of the concave portion but also the concave ridge line is included. Further, in the case of the top portion of the convex portion, not only the convex apex of the convex portion but also the convex ridge line is included. If the boundary between the concave portion and the convex portion is ambiguous, such as when the cross-sectional shape of the concavo-convex structure is a SIN curve or a free curved surface, or when the concavo-convex structure has multiple stages, the inflection point of the cross section is set as the concave portion in the cross section. It may be a boundary between a convex portion and a convex portion, or a minimum squared plane is obtained for the concave-convex structure forming the concave-convex surface, a portion located below the minimum squared curved surface is concave, and a portion located above is convex. It may be a department.

Hereinafter, a case where the member targeted for film formation of the selective reflection film 33 is the base material 34 will be considered. As shown in FIG. 6A, the concave-convex structure (concave-convex structure 342 in the example of the figure) forming the concave-convex surface of the member (base material 34) to be film-formed has a gap between a plurality of concave lens-shaped lens portions 343. In the case of a concave lens array that is arranged without a lens, each of the lens portions 343 may be a recess. In that case, the uneven surface may be composed of only concave portions. By doing so, the width w of each concave portion can be obtained by observing the ridge line (reference numeral 345) between the lens portions 343 corresponding to the boundary portion with the adjacent lens portion 343 from the upper surface of the base material. Here, when the boundary portion of the lens portion 343 has a curvature as in the region surrounded by the alternate long and short dash line in the figure, the position where the inclination becomes 0 is set as the apex of the boundary portion, and the ridge line consisting of the apex group is used. It may be observed from the upper surface of the substrate. FIG. 6A is a plan view showing a part of the uneven structure 342 cut out, and FIG. 6B is a cross section taken along the line AA'of the base material 34 having the uneven structure 342 shown in FIG. 6A. It is a figure.

The concave-convex structure forming the concave-convex surface may be a convex lens array in which the convex lens-shaped lens portions 343 are arranged without gaps. In that case, each of the lens portions 343 may be a convex portion. In that case, the uneven surface may consist only of the convex portion. By doing so, the width w of each convex portion can be obtained by observing the ridge line 345 between the lens portions 343 corresponding to the boundary portion with the adjacent lens portion 343 from the upper surface of the base material. As described above, the lens array is not limited to a regular one, but includes an array having irregularities in the lens shape and arrangement. Further, the case of a convex prism array in which a convex prism is arranged or a concave prism array in which a concave prism is arranged instead of the lens portion 343 may be the same as in the case of the lens array. Further, in the example shown in FIG. 6A, the concavo-convex structure 342 is exemplified as the concavo-convex structure forming the concavo-convex surface of the base material to be formed into a film, but it should be read as the concavo-convex structure 352 of the colored resin material layer 35. You may. In that case, the convex / concave type may be determined with the uneven surface 351 side of the colored resin material layer 35 facing upward.

In addition, when the shape of the concave portion is not closed, for example, when the bottom is extended such as an inverted semi-cylindrical shape or a groove shape, the width of the so-called groove (the length in the direction perpendicular to the extension direction). Alternatively, the length in the minor axis direction obtained by approximating the shape of the recess with an ellipse may be obtained as the width w of the recess. Further, in the case of a shape in which the bottom portion extends in two or more directions such that the concave ridge line is branched, the width w may be obtained at each of the branched ends, and the shape of the concave portion may be a plurality of polygons. The width w may be obtained by approximating an ellipse in each polygon. In addition, when the concave ridge line forming the bottom is not recognized, or when the shape is complicated even if it is closed, the shape of the concave portion is divided into a plurality of polygons, and each polygon is approximated by an ellipse. The width w may be obtained.

When the uneven surface is a rough surface such as a sandblasted surface, the concave and convex portions and their width w are not limited to the above.

Further, from the viewpoint of designability, if the width w of the concave portion and the convex portion becomes too large, they may be visually recognized. Therefore, the minimum value of the width w in each of the concave portion and the convex portion is preferably 200 μm or less, more preferably 100 μm or less. At this time, the width w of the concave portion may include the length in the extension direction of the shape in which the bottom is extended, or the length in the major axis direction when approximated by an ellipse, and the width w of the convex portion may include. It may include the length in the extension direction of the shape in which the bottom is extended and the length in the major axis direction when approximated by an ellipse.

Next, the inclination angle α of the uneven surface 331 of the selective reflection film 33 that functions as a scattering portion will be described. FIG. 7 is an explanatory diagram showing the relationship between the inclination angle α of the uneven surface 331 of the selective reflection film 33 functioning as a scattering portion and the reflection scattering of the visible light 102. In the example shown in FIG. 7, the uneven surface 331 on the first side is illustrated as the scattering portion, but when the second side is also an observation surface, the uneven surface 331 on the second side (concave surface 331b) is illustrated. Etc.) shall be the same. In that case, it should be noted that the path of visible light is in the opposite direction.

In particular, when the inclination angle α of the concave-convex surface 331 of the selective reflection film 33 becomes large, not only unintended reflected light is generated in infrared light due to the angle dependence of the selective reflection film 33, but also reflected scattering in visible light 102. It may be a factor to reduce the strength. Here, the surface serving as the reference (0 ° position) of the inclination angle α may be the plane direction (XY plane) of the substrate. Note that FIGS. 7 (a) and 7 (b) show the inclination angle α of the portion irradiated with the light beam.

For example, as shown in FIG. 7A, when the inclination angle α exceeds 45 °, the visible light 102 reflected by the selective reflective film 33 becomes light in a direction that advances the traveling direction at the time of incident (FIG. 7). See the white arrow inside). If the ratio of such light reflected forward is large in the total visible light reflected by the selective reflection film 33, the ratio of light reflected backward, which is the direction of retreating the traveling direction at the time of incident. Is relatively small. When the ratio of the light reflected backward is small, the amount of light (reflected light) returning to the incident interface (which is also the emission interface) of the visible light of the optical member 30 decreases, or sufficient scattering characteristics can be obtained. There is no risk. If the reflected scattering with respect to visible light is not sufficient, problems such as coloring of the optical member 30, that is, the color seen by the user deviating from a predetermined hue and the brightness being lowered occur. Further, when the amount of reflected light decreases, the amount of visible light emitted from the anti-visual side of the optical member 30 increases, causing problems such as an increase in stray light with respect to infrared light.

Further, as shown in FIG. 7B, when the inclination angle α exceeds 0.5 × asin (1 / n _s ), the visible light 102 reflected by the selective reflection film 33 is asin (1 / n). _s ) At an angle β of the above, it is easy to reach the emission interface (interface 353 in the figure) of the emission side member in contact with the selective reflection film 33. Here, n _s represents the refractive index of the member. In the case of a material in which the concave-convex structure portion of the member and the portion constituting the exit interface are different (for example, a laminated structure of the base material 34a and the colored resin material layer 35 in FIGS. 5A and 5B), Since the portion of the member constituting the exit interface forms an interface with air, the refractive index of the portion may be used as _ns .

As shown in FIG. 7 (b), when the visible light 102 reaches the emission interface at an angle β of asin (1 / n _s ) or more, total reflection occurs at the emission interface, so that the ratio of such visible light is high. If it is large, the amount of reflected light may decrease or sufficient scattering characteristics may not be obtained, as in the above case.

Therefore, it is preferable that the uneven surface 331 of the selective reflection film 33 has an inclination angle α of 45 ° or less in 90% or more of the effective region in which visible light is incident, and the inclination angle α is 0.5 × asin ( It is more preferable that the region within 1 / n _s ) is 90% or more, and it is further preferable that the inclination angle α is within 45 ° in all the regions in the effective region, and in all the regions in the effective region. It is more preferable that the inclination angle α is within 0.5 × asin (1 / n _s ).

Further, the above-mentioned definition of the inclination angle α is about the inclination angle of the uneven surface 331 of the selective reflection film 33, but the uneven shape of the uneven surface 331 of the selective reflection film 33 is the uneven surface of the member to be formed. Since it can be regarded that the uneven shape of the above is imitated, the above-mentioned regulation of the inclination angle α can be applied to the uneven surfaces of the members on both sides of the selective reflection film 33. If at least the uneven surface of the member on both sides of the selective reflection film 33, which is the target of film formation, satisfies the above-mentioned regulation of the inclination angle α, the number of gently inclined portions increases, and the film thickness is uniform. This is preferable because it facilitates the formation of the selective reflection film 33. At this time, when the concave-convex structure forming the concave-convex surface of the member has a configuration in which a lens portion having a curved surface capable of defining a constant radius of curvature, such as a lens array, is arranged without a gap, in addition to the tilt angle α or the tilt angle α. It is preferable to satisfy the following conditions instead of.

That is, consider the case where the radius of curvature of the lens portion is R and the distance to the apex of the boundary portion of the lens portion farthest from the center of the lens portion is the radius r of the lens portion. At this time, the ratio r / R of the radius of curvature R and the radius r is preferably a numerical value γ or more corresponding to the inclination angle α of 45 ° or more, and the inclination angle α is 0.5 × asin (1 / n _s ). It is more preferable that the value is ζ or less corresponding to the following. Here, for r / R, both the numerical value γ and the numerical value ζ depend on the refractive index n _s . For example, when the refractive index n _s is 1.51, the numerical value γ is 0.71 and the numerical value ζ is 0.35. In a more general case, the inclination of the lens portion is α = atan [(r / R) / {1- (r / R) ² } ^0.5 ], and the condition of total reflection at the exit interface is n. Due to the relational expression of _s sin β = 1 and 2α = β, r / R = tan {0.5 × asin (1 / n _s )} / [1 + tan ² {{0.5 × asin (1 / n) _s )}] The value is obtained by ^0.5 .

Further, from the viewpoint of designability, particularly color development performance, the FWHM of the visible light reflection / scattering angle of the entire optical member 30 is preferably 5 ° or more, more preferably 15 ° or more, still more preferably 30 ° or more. Further, the ratio of the total amount of reflected scattered light to the amount of incident light at a certain wavelength in the target wavelength band of visible light for the entire optical member 30 is preferably 50% or more, more preferably 75% or more. By doing so, the brightness of the observed color of the optical member 30 can be increased.

Further, the information on the inclination angle α can also be obtained by taking out one of the members on both sides of the selective reflection film 33, incident light on the member, and measuring the scattering characteristics thereof. For example, as shown in FIG. 7 (c), when the inspection light 103 is incident on a substrate having a refractive index of n _s in which one surface is inclined at α and the opposite surface is inclined at 0 °, Snell's law is generated. According to the law, it is refracted in the direction of the angle γ such that sin α = n _s sin γ. On the other hand, since the refracted light ray is incident on the opposite surface at an angle (α-γ), if the angle of the light ray emitted from the opposite surface is δ, then n _s sin (α-γ) = sin δ. As a result, δ = asin [sinα × {(ns2 ^- _sin2α ) ^{0.5 -} cosα}]. Therefore, information on the inclination angle α of the uneven surface can be obtained by examining the refractive index of the member and the scattering characteristics of the light scattered by the uneven surface.

For example, when the refractive index n _s of the member with respect to the inspection light 103 is 1.51, when α is 45 °, δ is 26.3 °. Therefore, when light is incident on the member, 26. When there is a light beam scattered at an angle of 3 ° or more, the uneven surface of the member includes an inclination of 45 ° or more. Further, when α is 0.5 × asin (1 / n _s ) = 20.7 °, δ is 10.9 °. Therefore, when light is incident on the member, it is 10.9 ° or more. When there is a light beam scattered at an angle, the uneven surface of the member includes an inclination of 0.5 × asin (1 / n _s ) ° or more.

FIG. 8 is a graph showing an example of the angle dependence of the light amount distribution of the transmitted component by the optical member 30 with respect to the incident of infrared light. In FIG. 8, the horizontal axis represents the emission angle θ [°] of the transmitted component, and the vertical axis represents the light intensity. It is considered that the incident infrared light travels in the Z direction. As shown in FIG. 8, the infrared light transmitted through the optical member 30 of this example (for example, the base material 34 of FIG. 3, the selective reflection film 33, and the colored resin material layer 35) includes straight-line transmitted light and transmitted scattered light. Can be roughly divided into. As described above, due to the combined action of the selective reflection film 33 and the uneven filling members on both sides thereof, a large linear transmitted light can be obtained with respect to the infrared light incident on the optical member 30.

However, at this time, the amount of transmitted light may be modulated due to the angle dependence of the selective reflection film 33, or scattering may occur due to the edge portion formed at the interface of each uneven structure. Therefore, assuming that the ratio of the amount of light transmitted straight through to the amount of incident light of infrared light in the optical member 30 is T ₀ , T ₀ is preferably 75% or more, more preferably 85% or more, still more preferably 90% or more. , 95% or more is most preferable. A haze value may be used instead of T ₀ . In that case, the haze value of the infrared light of the optical member 30 is preferably less than 25%, more preferably less than 15%, still more preferably less than 10%, and most preferably less than 5%. As the haze value, as described in JIS K 7136, among the transmitted light passing through the test piece, the transmitted light deviated by 0.044 rad (2.5 °) or more from the incident light due to forward scattering. It may be calculated as a percentage. In JIS K 7136, the angle range corresponding to the straight transmitted light is within 2.5 °, but the transmitted light in the angle range narrower than 2.5 ° such as 1.5 ° or less can be regarded as the straight transmitted light. good.

Further, when the light other than the straight transmitted light among the infrared light transmitted through the optical member 30 is regarded as transmitted scattered light, the ratio of the total light amount of the transmitted scattered light to the incident light amount of the infrared light in the optical member 30. When is T ₁ , the transmitted scattered light can be evaluated by T ₁ '= T ₁ / (T ₀ + T ₁ ) × 100 [%]. T _1'is preferably 10% or less, more preferably 5% or less, still more preferably 2% or less. At this time, T _1'does not measure all transmitted light for infrared light, but targets the light emitted within a predetermined emission angle θ ₂ according to the specifications of the device that handles infrared light. May be measured. In the case of limiting the angle of transmitted light used for measurement in this way, when θ ₂ is 10 ° or less, T _1'is preferably 3% or less, more preferably 2% or less, and further preferably 1% or less. preferable.

As a method for manufacturing the optical member 30 of this example, as described above, a selective reflection film 33 (a dielectric multilayer film or the like) is formed on a base material 34 having an uneven surface having a desired uneven shape, and then a colored resin is formed. Examples include a method of filling the material.

FIG. 9 is an explanatory diagram showing an example of a method for manufacturing the optical member 30 of this example. In the example shown in FIG. 9, first, a base material (surface microfabricated base material) 34b having a concavo-convex surface 341b having a fine concavo-convex shape is prepared (step (a)). Next, a multilayer film (selective reflective film 33) is formed on the surface microfabricated substrate (step (b)). The surface of the formed multilayer film is an uneven surface 331 that follows the uneven shape of the uneven surface 341b. Next, the colored resin material 35'is dropped onto the formed multilayer film (step (c)). Next, in order to flatten the upper surface of the colored resin material, a second base material 34a such as glass is covered, and the colored resin material is cured while pressing as necessary (step (d)). In the step (d), it can be cured by heat treatment or UV treatment according to the characteristics of the colored resin material.

Further, FIG. 10 is an explanatory diagram showing another example of the manufacturing method of the optical member 30 of this example. In the example shown in FIG. 10, the colored resin material 35'is dropped onto the multilayer film (step (c)), and then covered with a base material 36 such as glass that has been subjected to a mold release treatment such as fluorine or silicone to be colored. The resin material is cured (step (d)). After curing, the base material 36 is peeled off (step (e)). In this example, the height of the optical device can be reduced.

Next, another example of realizing the scattering unit 12 by utilizing the uneven surface of the selective reflection unit will be described. FIG. 11A is a schematic cross-sectional view showing a configuration example of an optical member 40 that realizes the scattering portion 12 by utilizing the uneven surface of the selective reflection portion. 11 (b) is an exploded sectional view of a main part of the optical member 40 shown in FIG. 11 (a). The optical member 40 shown in FIG. 11 includes a base material 44, a cholesteric phase liquid crystal layer 43, and a colored resin material layer 45. An uneven surface 431 is formed on at least the first side of the cholesteric phase liquid crystal layer 43 of this example. Further, a concavo-convex surface 451 having a shape substantially fitting with the concavo-convex surface 431 is also formed on at least the first side member in contact with the cholesteric phase liquid crystal layer 43, that is, the surface of the colored resin material layer 45 on the cholesteric phase liquid crystal layer 43 side. Has been done.

In this example, the cholesteric phase liquid crystal layer 43 corresponds to the selective reflection unit 13. Further, the uneven surface 431 of the cholesteric phase liquid crystal layer 43 corresponds to the scattering portion 12. Further, the colored resin material layer 45 corresponds to the specific visible light absorption unit 15. In this example, the cholesteric phase liquid crystal layer 43 having the uneven surface 431 and the colored resin material layer 45 are collectively referred to as an absorption / reflection / scattering unit 41. Also in this example, a member that is in contact with the uneven surface 431 of the cholesteric phase liquid crystal layer 43 and has a flat surface on the opposite side is also referred to as an uneven filling member. In the example shown in FIG. 11, the colored resin material layer 45 corresponds to the uneven filling member.

This example is basically the same as the optical member 30 except that the optical member 30 is provided with the cholesteric phase liquid crystal layer 43 having the concave-convex surface 431 instead of the selective reflection film 33 having the concave-convex surface 331. It's fine. Therefore, a configuration in which a second base material 44 (base material 44a in the figure) is further provided on the colored resin material layer 45 as shown in FIG. 12 (a), or a colored resin material as shown in FIG. 12 (b). As shown in FIG. 13, the concave-convex surface 431b is also formed on the second side of the cholesteric phase liquid crystal layer 43, and the second colored resin material layer is further formed. A configuration including 45 (colored resin material layer 45b) is also possible. In the example shown in FIG. 12B, the base material 44a is used as the uneven filling member. Further, in the example shown in FIG. 13, the colored resin material layers 45a and 45b are used as the uneven filling member.

In this example, the concavo-convex surface 431 of the cholesteric phase liquid crystal layer 43 is, for example, one of the members in contact with the concavo-convex surface 431 (the colored resin material layer 45 of FIGS. 11 and 12 (a) and the base material of FIG. 12 (b)). A concavo-convex structure is formed on the surface of (44a, etc.) to form an concavo-convex surface, and the concavo-convex surface is turned inside, and the other member (base material 44 in FIG. 11, base material 44b in FIGS. 12 (a), 12 (b), etc.) It can be formed by sandwiching the cholesteric phase liquid crystal layer 43 between the two. At this time, if a concavo-convex structure is formed on the surface of the other member to form an concavo-convex surface and the concavo-convex surfaces of both members are inside and sandwiched, the configuration shown in FIG. 13 can be obtained.

In this example, the cholesteric phase liquid crystal layer 43 and the member (concavo-convex filling member) in contact with the uneven surface 431 of the cholesteric phase liquid crystal layer 43 have substantially the same refractive index at least in the target wavelength band in the infrared region. It is good. The refractive index of the cholesteric phase liquid crystal layer 43 may be the average refractive index. By doing so, it is possible to prevent refraction caused by the concave-convex structure portion of the cholesteric phase liquid crystal layer 43 and the concave-convex filling member with respect to the infrared light 101a and the infrared light 101b, and as a result, high straight-line transparency can be obtained. ..

The cholesteric phase liquid crystal layer 43 is configured to reflect visible light at a certain rate or more and transmit infrared light at a certain rate or more. The cholesteric phase liquid crystal has a selective reflection band due to the spiral structure of the liquid crystal molecules, and by providing the selective reflection band in the visible region, only visible light can be selectively reflected.

More specifically, in the cholesteric phase liquid crystal layer 43, the spiral pitch p and the average refractive index _nc of the liquid crystal may be adjusted. Generally, the selective reflection wavelength λ _R of the cholesteric phase liquid crystal is given by the following equation (2).

λ _R = p · n _c ... (2)

Therefore, in the above equation (2), the spiral pitch p and the average refractive index _nc of the liquid crystal may be adjusted so that the selective reflection wavelength λ _R becomes the same as the wavelength of visible light to be selectively reflected. Examples of the method for adjusting the spiral pitch p include a method for adjusting the HTP (Helical Twisting Power) and the concentration of the chiral agent, in addition to the orientation control.

Although FIGS. 11 to 13 show an example in which the optical member 40 includes one cholesteric phase liquid crystal layer 43, the cholesteric phase liquid crystal layer is not limited to a single layer. For example, the optical member 40 may include a plurality of cholesteric phase liquid crystal layers 43 having different selective reflection bands (so as to be laminated in the thickness direction (Z direction)). At this time, a plurality of cholesteric phase liquid crystal films or the like containing the base material 44 may be laminated. As an example, three types of cholesteric phase liquid crystal layers or cholesteric phase liquid crystal films having the center of the selective reflection band at 430 nm, 530 nm, and 630 nm may be laminated. With such a configuration, infrared light can be transmitted while reflecting and scattering visible light in a wide band. In such a case, the colored resin material layer 45 may be laminated on the cholesteric phase liquid crystal layer or the cholesteric phase liquid crystal film of the uppermost layer (the layer on the most first side).

Further, since the cholesteric phase liquid crystal has a feature of reflecting circularly polarized light corresponding to the direction of the spiral, as shown in FIG. 14, a second selective reflection unit 46 is provided on the anti-visual side of the cholesteric phase liquid crystal layer 43. Further may be provided. With such a configuration, it is possible to reflect and scatter both circularly polarized lights. In that case, the absorption / reflection / scattering unit 41 may be included including the second selective reflection unit 46.

The second selective reflection unit 46 may be configured to reflect visible light in a wavelength band including the selective reflection band of the cholesteric phase liquid crystal layer 43 at a certain ratio or more and transmit infrared light at a certain ratio or more, for example. , It may be a dielectric multilayer film such as that used for the mirror layer of a dichroic mirror. The second selective reflection unit 46 is not limited to the anti-visual side of the member sandwiching the cholesteric phase liquid crystal layer 43, and may be provided, for example, between the member and the cholesteric phase liquid crystal layer 43. .. For example, when a cholesteric phase liquid crystal display exhibiting selective reflection with respect to right circularly polarized visible light 102c is used as the cholesteric phase liquid crystal layer 43, the transmitted left circularly polarized visible light 102d is reflected by the second selective reflection unit 46. You may. Since the relationship between the second selective reflection unit 46 and the cholesteric phase liquid crystal layer 43 is the same as that in Patent Document 3 described above, the description thereof will be omitted. Even in such a configuration, not only sufficient reflection scattering can be obtained for light 1021 having a specific wavelength among visible light 102, but also scattering for infrared light can be greatly reduced.

As for the uneven surface 431 of this example, it is more preferable that the shape has many smooth curved surfaces (including free curved surfaces, aspherical surfaces, and spherical surfaces) because the orientation of the liquid crystal is improved.

The other points are the same as those of the optical member 30.

As shown in FIG. 15, a configuration including a cholesteric phase liquid crystal layer 53 having no uneven surface is also possible. The cholesteric phase liquid crystal layer 53 is configured to reflect and scatter visible light at a certain rate or more and transmit infrared light at a certain rate or more. For example, the cholesteric phase liquid crystal layer 53 may be a cholesteric phase liquid crystal layer having a plurality of regions having different orientation axes in the plane of the layer. Such a cholesteric phase liquid crystal layer 53 can be formed, for example, by setting the selective reflection band in the visible region and not applying the liquid crystal alignment treatment when forming the cholesteric phase liquid crystal layer. Due to such a disorder of orientation, reflection scattering can be performed in the set selective reflection band. In this example as well, the colored resin material layer 55 may be provided on at least the first side of the cholesteric phase liquid crystal layer 53 as the scattering unit 12 and the selective reflection unit 13. The surface of the colored resin material layer 55 of this example on the cholesteric phase liquid crystal layer 53 side may be flat rather than uneven. Further, in this example, the above limitation regarding the difference in refractive index between the cholesteric phase liquid crystal layer 53 and the colored resin material layer 55 may be ignored.

The other points are the same as those of the optical member 40.

Next, an example of realizing the scattering unit 12 by using the fine particle-containing resin will be described. FIG. 16 is a schematic cross-sectional view showing an example of an optical member having a fine particle-containing resin layer 62 as a scattering portion 12. The optical member 60 shown in FIG. 16 includes a base material 64, a selective reflection unit 63, a fine particle-containing resin layer 62, and a colored resin material layer 65. In this example, the selective reflection unit 63, the fine particle-containing resin layer 62, and the colored resin material layer 65 are collectively referred to as an absorption / reflection / scattering unit 61.

The fine particle-containing resin layer 62 uses a resin material having transparency to visible light and infrared light as a binder, and the resin material uniformly contains fine particles having a refractive index different from that of the resin at least in the visible region. It may be dispersed.

At this time, as described above, by adjusting the particle size of the fine particles and the ratio of the refractive index of the fine particles to the resin material serving as the binder, it is possible to increase the scattering with respect to visible light and reduce the scattering with respect to infrared light. For example, by adding a material containing a dye or pigment having an absorption band in the vicinity of the infrared region to the resin, a large refractive index difference is generated between the target wavelength region in the visible region and the target wavelength region in the infrared region. Can be made to. The difference in the refractive index in the target wavelength region in the infrared region may be small or the refractive index may be adjusted to be substantially the same between the resin and the fine particles.

It is the same as the other examples described above except that the scattering portion 12 is provided with the fine particle-containing resin layer 62.

Further, FIG. 17 shows an example of an optical member 70 in which the fine particle-containing resin layer 62 and the colored resin material layer 65 are realized by one functional resin layer (hereinafter referred to as a scattering absorption resin layer 76). FIG. 17 is a schematic cross-sectional view showing an example of an optical member 70 having a scattering absorption resin layer 76 as a scattering portion and a specific visible light absorbing portion. The optical member 70 shown in FIG. 17 includes a base material 74, a selective reflection unit 73, and a scattering absorption resin layer 76. In this example, the selective reflection unit 73 and the scattering / absorbing resin layer 76 are collectively referred to as an absorption / reflection / scattering unit 71.

The scattering absorption resin layer 76 uses a resin material having transparency to visible light and infrared light as a binder, and the resin material includes the fine particles used in the fine particle-containing resin layer 62 and the above-mentioned colored resin. The coloring material (dye, organic pigment, etc.) used for the material layer 65 may be uniformly dispersed.

It is the same as the other examples described above except that the scattering unit 12 and the specific visible light absorbing unit 15 are provided with the scattering absorbing resin layer 76.

Next, an example of realizing the scattering unit 12 by using the diffraction structure will be described. 18 (a) and 18 (b) are schematic cross-sectional views showing an example of an optical member 20 having a diffraction structure 22 as a scattering portion 12. The optical member 20 shown in FIG. 18A includes a base material 24, a selective reflection unit 23, a diffraction structure 22, and a colored resin material layer 25. In this example, at least the recess 222 of the diffraction structure 22 is filled with the colored resin material layer 25. In this example, the selective reflection unit 23, the diffraction structure 22, and the colored resin material layer 25 are collectively referred to as an absorption / reflection / scattering unit 21. Further, a member that is in contact with the diffraction structure 22 and has a flat surface on the opposite side is also referred to as a concavo-convex filling member. In the example shown in FIG. 18A, the colored resin material layer 25 corresponds to the uneven filling member.

Further, the optical member 20 shown in FIG. 18B includes a base material 24, a selective reflection portion 23, a diffraction structure 22, a filling portion 26, and a colored resin material layer 25. In this example, at least the recess 222 of the diffraction structure 22 is filled by the filling portion 26. In this example, the selective reflection unit 23, the diffraction structure 22, the filling unit 26, and the colored resin material layer 25 are collectively referred to as an absorption / reflection / scattering unit 21. In the example shown in FIG. 18B, the filling portion 26 corresponds to the uneven filling member.

The diffraction structure 22 does not have any specific configuration as long as it exhibits a diffractive action with respect to visible light at least and can suppress the manifestation of the diffractive action with respect to infrared light with respect to the manifestation of the diffractive action with visible light. Although FIG. 18 shows a concave-convex structure having a rectangular cross section as the diffraction structure 22, the diffraction structure 22 is not limited to the concave-convex structure having a rectangular cross section.

In the example shown in FIG. 18, the difference in refractive index between the concave portion 222 and the convex portion 221 of the diffraction structure 22 is Δn, the incident wavelength is λ, and the height of the convex portion 221 or the depth of the concave portion 222 is d. The diffraction characteristics of the diffraction structure 22 vary depending on Δnd / λ, which is a coefficient of the phase term of the electric field of the diffraction structure 22.

Here, since the visible light 102 reflected by the selective reflection unit 23 reciprocates in the diffraction structure 22, the coefficient is calculated as 2Δnd / λ. On the other hand, for the infrared light 101a and the infrared light 101b transmitted through the selective reflection unit 23, since the diffraction structure 22 is transmitted only once, the calculation may be performed with Δnd / λ as it is. Depending on the interference conditions, the closer the value of these coefficients is to a value obtained by multiplying 1/2 such as 0.5 by an odd number, the smaller the amount of light of the 0th-order diffracted light, and the closer to an integer such as 0 or 1, the closer to the 0th-order diffracted light. The amount of light increases (see FIGS. 19 (a) and 19 (b)). In FIGS. 19A and 19B, the values of these coefficients were calculated with d = 270 nm and Δn = 0.45.

For example, the 0th-order diffraction efficiency of a rectangular diffraction grating, that is, the ratio of components that transmit straight through to incident light, can be calculated by cos (πφ) ² with the coefficient of the phase term as φ, but the 0th-order diffraction efficiency η0 is set to φ. Comparing the case where = Δnd / λ, which is the coefficient of the phase term when passing once (transmission), and the case where φ = the coefficient of the phase term when passing twice (reflection), 2Δnd / λ, The zero-order diffraction efficiency determined by 2Δnd / λ (characteristic shown by the solid line in FIG. 19), which is the coefficient of the phase term of reflection in visible light, can be reduced to less than 30%, and the coefficient of the phase term of transmission in infrared light. The transmission 0th-order diffraction efficiency determined by Δnd / λ can be increased to about 80% or more.

Further, in this example, it is preferable that the material of the convex portion 221 and the uneven filling member have substantially the same refractive index at least in the target wavelength band in the infrared region. For example, the convex portion 221 is a multilayer film having a reflection band in the vicinity of the infrared region, or a dye having absorption in the vicinity of the infrared region (between the visible region and the infrared region or on the longer wavelength side than the target wavelength region in the infrared region). The recess 222 may be filled with a material having a refractive index close to or matching that of the material in the infrared region (particularly the target wavelength region). In general, a multilayer film having a reflection band or a material having an absorption has an abnormal dispersion of the refractive index, and the refractive index in the vicinity of the reflection band or the absorption band changes abruptly. By utilizing such characteristics, it is possible to adjust so that the difference in refractive index between the target wavelength region in the visible region and the target wavelength region in the infrared region becomes large. If the diffraction structure 22 can be adjusted to be formed by a combination of such a material and a material having a refractive index substantially matching at least in the target wavelength region in the infrared region, the diffraction effect can be generated only in visible light. Is also possible.

Further, the diffraction structure 22 is preferably capable of imparting a two-dimensional scattering action such as deflecting light (particularly visible light) not only in the X direction but also in the Y direction (component) by the diffraction action. For example, it may have a two-dimensional uneven structure.

FIG. 20 is a graph showing an example of the angle dependence of the light amount distribution of the transmitted component by the diffraction structure 22 with respect to the incident of infrared light. In FIG. 20, the horizontal axis represents the emission angle θ [°] of the transmitted component, and the vertical axis represents the light intensity. Generally, when light is incident on a diffraction structure having a function of exhibiting a diffractive action, it is roughly classified into 0th-order diffracted light which becomes straight-line transmitted light and so-called diffractive light, that is, high-order diffracted light which becomes deflected light traveling in a direction other than straight-line. It produces two types of diffracted light. Generally, the 0th-order diffracted light is sufficiently stronger than the higher-order diffracted light. Therefore, even if infrared light is incident on the diffraction structure 22 to generate higher-order diffracted light, it is easy to obtain a strong contrast as shown in FIG.

When the ratio of the light amount of the 0th-order diffracted light to the incident light amount of the infrared light in the optical member 20 is T ₀ , it is preferable that the diffraction structure 22 is adjusted so that T ₀ is 75% or more. The T ₀ is preferably 75% or more, more preferably 85% or more, further preferably 90% or more, and most preferably 95% or more. The "0th-order diffracted light" in this case does not include the reflected 0th-order diffracted light. Hereinafter, when the infrared light is referred to as "0th-order diffracted light", it means the 0th-order diffracted light of the transmitted light. As described above, a haze value may be used instead of T ₀ .

In the diffraction structure 22, the ratio of the total amount of high-order diffracted light to the amount of incident light of infrared light in the optical member 20 is T ₁ , and T ₁ '= T ₁ / (T ₀ + T ₁ ) × 100 [%]. If so, it is preferable to adjust T _1'to be 10% or less. The T _1'is preferably 10% or less, more preferably 5% or less, still more preferably 2% or less. The above-mentioned "high-order diffracted light" does not include a reflective component. Hereinafter, when the infrared light is referred to as "high-order diffracted light", it refers to diffracted light other than the 0th-order of the transmitted components, that is, the first-order diffracted light, the second-order diffracted light, the third-order diffracted light, and the like. Further, when limiting the angle of transmitted light used for measurement and setting θ ₂ to 10 ° or less, as described above, T _1'is preferably 3% or less, more preferably 2% or less. 1% or less is more preferable.

Further, although not shown, the selective reflection portion 23 and the diffraction structure 22 may be integrally formed by providing a groove on the surface of the selective reflection portion 23 to use the material of the convex portion 221. It is possible to reduce the reflection when the structure 22 (more specifically, the convex portion 221) is incident on the selective reflection unit 13, and to increase the linear transmittance of infrared light.

Further, in general, when high-order diffracted light is generated and the number of high-order diffracted light generated by the diffraction structure 22 is N, the amount of high-order diffracted light can be approximated to decrease in proportion to 1 / N. The number N of the generated high-order diffracted light is preferably 100 or more, more preferably 1000 or more, because the scattering property can be increased. Further, in general, if the diffraction angle due to the higher-order diffracted light is to be increased, the uneven structure (lattice pitch) can be reduced, so that the uniformity when the element surface is visually recognized can be improved. Therefore, as the diffraction characteristic of the diffraction structure 22 alone, the full width at half maximum (hereinafter, FWHM) of the light amount distribution of the higher-order diffracted light of visible light is preferably 5 ° or more, more preferably 10 ° or more, and further preferably 20 ° or more.

As described above, according to the present embodiment, it has high reflection and scattering property for light of a specific wavelength that expresses a desired color among visible light, and has high absorption for light other than light of a specific wavelength. Moreover, it is possible to provide an optical member including a reflection scattering portion having high straight-line transmission of infrared light.

Further, since the color tone can be easily adjusted by combining the absorbing material of the specific visible light absorbing unit 15, it is possible to provide an optical member having a wide color reproduction range without complicated design.

In each of the above optical members, an absorption member that absorbs visible light and transmits infrared light on the anti-visual side of the absorption / reflection scattering portion or the base material that supports it, or an absorption member that reflects visible light and transmits infrared light. It may have any of the reflective members that transmit light.

21 (a) is a configuration diagram showing an example of the optical member 10 including the absorption member, and FIG. 21 (b) is a configuration diagram showing an example of the optical member 10 including the reflection member. In the example shown in FIG. 21A, the optical member 10 is further provided with an absorption member 16 that absorbs visible light and transmits infrared light on the anti-visual side of the absorption / reflection / scattering unit 11. Further, in the example shown in FIG. 21B, the optical member 10 includes a reflective member 17 that reflects visible light and transmits infrared light on the anti-visual side of the absorption / reflection / scattering unit 11.

With such a configuration, the transmitted visible light can be further reduced. Further, the absorbing member 16 may be realized by a base material (for example, base materials 34, 34a, 34b, 44, 44a, 54, 64, 74, etc.) included in the above optical member. That is, the absorbing member 16 may be formed by including the absorbing agent or the like in the base material.

Embodiment 2.
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 22 is a block diagram showing an example of an optical device according to a second embodiment of the present invention.

The optical device 100 shown in FIG. 22 has an infrared light emitting unit 2 and / or an infrared light receiving unit 3 in the housing 4. Further, the optical device 100 is provided with an optical member 1 so as to cover the opening provided in the housing 4. With such a configuration, the infrared light is received and emitted to the outside of the housing 4 through the optical member 1.

The optical device 100 includes, for example, a camera device that captures an image using infrared light, a measuring device such as a distance sensor that detects the distance of an object and the presence or absence of a nearby object, and a proximity sensor using infrared light. It is an optical device using infrared light, such as a communication device that performs information communication using infrared light and an authentication device that performs ecological authentication such as iris, fingerprint, and vein authentication using infrared light.

Further, the housing 4 may surround a device exhibiting functions other than the infrared light emitting unit 2 and the infrared light receiving unit 3.

The infrared light emitting unit 2 is not limited to a lamp or the like, and may be an LED or a laser light source. Further, the infrared light emitting unit 2 is not limited to the one having a function of emitting infrared light by itself, and may be a transmitting unit that outputs infrared light emitted by another unit.

Further, the infrared light receiving unit 3 is not limited to a single light receiving element such as a photodiode, and may be one that acquires image information such as a CMOS sensor.

The optical member 1 is an infrared light transmission filter having a function of transmitting infrared light, reflecting and scattering light of a specific wavelength among visible light, and absorbing light other than the specific wavelength, and is an outer surface of the housing 4. When viewed from, it looks like it is colored in a specific color. The optical member 1 may be, for example, any of the optical members 10 to 70 shown in the first embodiment.

With such a configuration, it is possible to obtain an optical device in which the opening of the housing appears to be colored in a specific color without deteriorating the transmission sensitivity and / or the reception sensitivity of infrared light.

First, a preparation example of a red colored resin material as a specific visible light absorber 15 for developing red color is shown. In this example, acryloylmorpholine (manufactured by KJ Chemicals, trade name ACMO) and tricyclodecanedimethanol diacrylate (manufactured by Shin-Nakamura Industrial Co., Ltd., trade name A-DCP) are mixed with an equal amount composition and red dispersion manufactured by Tokushiki Co., Ltd. Liquid (8649 RED, pigment red 177, average particle size 86 nm) was added. Then, the solvent was distilled off under reduced pressure, and IC754 (manufactured by BASF Japan Ltd.) was further added as a photoinitiator to obtain a red coloring material. At this time, the solid content concentrations of the red pigment and the photoinitiator were 5% by weight and 3% by weight, respectively. FIG. 23 shows the spectral transmittance when the film is formed to 10 μm. The refractive index of an equal amount mixture of acryloylmorpholine and tricyclodecanedimethanol diacrylate at 940 nm was 1.52.

Moreover, the preparation example of the green colored resin material as the specific visible light absorption part 15 for developing green color is shown. In this example, a green dispersion (8438GREEN, a mixture of pigment yellow 180 and pigment blue 15: 1, average particle size 340 nm) manufactured by Tokushiki Co., Ltd. is added to an equal amount composition of acryloylmorpholine and tricyclodecanedimethanol diacrylate. rice field. Then, the solvent was distilled off under reduced pressure, and IC754 was further added as a photoinitiator to prepare a green colored resin material. At this time, the solid content concentrations of the green pigment and the photoinitiator were both 3% by weight. FIG. 23 shows the spectral transmittance when the film is formed to 10 μm.

Further, an example of preparing a blue colored resin material as the specific visible light absorber 15 for expressing blue color is shown. A green dispersion (8537BLUE, pigment blue 15: 1, average particle size 340 nm) manufactured by Tokushiki Co., Ltd. was added to an equal amount composition of acryloylmorpholine and tricyclodecanedimethanol diacrylate. Then, the solvent was distilled off under reduced pressure, and IC754 was further added as a photoinitiator to obtain a blue colored resin material. At this time, the solid content concentrations of the blue pigment and the photoinitiator were both 3% by weight. FIG. 23 shows the spectral transmittance when the film is formed to 10 μm.

In FIG. 23, “R” represents the spectral transmittance of the red colored resin material after film formation, “G” represents the spectral transmittance of the green colored resin material after film formation, and “B” represents the blue colored resin material. Represents the spectral transmittance of the film after film formation.

Next, an example of an optical member using each of the above colored resin materials will be shown. This example is an example of the optical member 30 having the configuration shown in FIG.

First, a table composed of SiO ₂ and Ta ₂ O ₅ as a selective reflection film 33 on a glass substrate having a thickness of 0.7 mm and having a concave-convex surface 341 having a refractive index of 1.51 at a wavelength of 950 nm. A multilayer film having the configuration shown in 2 was formed.

FIG. 24 is a graph showing the transmittance characteristics of the multilayer film of this example. As shown in FIG. 24, the multilayer film of this example exhibited low transmittance for light in the visible region and high transmittance characteristics for light having a wavelength of 900 nm or more.

The surface of the glass substrate is finely processed, and it has an uneven surface 341 including a large number of irregularly arranged spherical concave lens portions 343 as shown in FIG. Each lens portion 343 is arranged so that the apex position is located within a radius of 25% of the pitch with respect to the honeycomb arrangement having a reference pitch of 60 μm. Such an uneven surface was formed by wet-etching a Mo mask having an initial opening with a diameter of 3 μm at a position corresponding to the apex position of each lens portion 343 with respect to one surface of the glass substrate. The average radius of curvature of the lens portions 343 on the uneven surface was calculated to be 100 μm, and the average inclination angle at the boundary portion of the adjacent lens portions 343, that is, the end portion of each lens portion 343 was calculated to be 18 °. The angle is smaller than 0.5 × asin (1 / 1.51). Further, the uneven surface of the base material of this example has at least 97% or more of the region where the inclination angle is within 0.5 × asin (1 / 1.51) in the effective region where visible light is incident. .. The average r / R of the lens unit 343 is 0.32. Further, the plan view of the element was observed as a structure having a ridge line similar to that of FIG. 6, and the width w of all the recesses in the effective region where visible light was incident was 5 μm or more. Further, the average sag (depth) of the lens portion 343 on the uneven surface was 4.6 μm.

When the multilayer film is formed on the uneven surface of the glass substrate, the surface of the multilayer film also has an uneven shape. That is, the uneven surface 331 having substantially the same shape as the uneven surface of the glass substrate is also formed on the multilayer film. In this way, a base material having a multilayer film having an uneven surface 331 was obtained. Using the 20 mm square (20 × 20 mm) base material thus obtained, the following three types of optical members 30 (optical members 30R, 30G, 30B) were produced.

The optical member 30R is an example in which the above-mentioned red colored resin material is used as the material of the colored resin material layer 35. Further, the optical member 30G is an example in which the above-mentioned green colored resin material is used as the material of the colored resin material layer 35. Further, the optical member 30B is an example in which the above-mentioned blue colored resin material is used as the material of the colored resin material layer 35.

7 μL of each colored resin material was dropped onto the multilayer film of the obtained 20 mm square base material. After the dropping, it was covered with D263 glass (manufactured by Matsunami Glass Industry Co., Ltd.) having a thickness of 0.21 mm, and pressed so that the upper surface of the colored resin material was flat. In that state, the optical members 30R, 30G, and 30B are obtained by irradiating UV light at 300 mW / cm2 for 10 seconds with a fiber type UV exposure machine (manufactured by Hamamatsu Photonics Co., Ltd .: spot light LC6) which is an ultraviolet irradiation device. rice field. The average in-plane thickness of the colored resin material layer in each of the obtained optical members 30R, 30G, and 30B is 15 μm, and all the recesses in the uneven surface 331 formed on the multilayer film on the glass substrate are covered. The upper surface is flattened.

The spectral transmittances of the obtained optical members 30R, 30G, and 30B are shown in FIG. 25. Table 3 shows the results of color component analysis of the obtained optical members 30R, 30G, and 30B using a spectrocolorimeter CM-2600d manufactured by Konica Minolta.

From this, it can be seen that the transmittance is low at any wavelength of visible light, while the transmittance is high in the near infrared (for example, 940 nm), and the desired color is expressed from the color measurement results. Further, when the color of the optical members 30R, 30G, and 30B was confirmed by changing the viewing angle, there was no change in the color when viewed from any angle.

The present invention can be suitably used for various devices that utilize infrared light.

100 Optical device 2 Infrared light emitting part 3 Infrared light receiving part 4 Housing 1, 10, 20, 30, 30R, 30G, 30B, 40, 50, 60, 70 Optical member 11 Absorption reflection scattering part 12, 12a, 12b Scattering part 13 Selective reflecting part 14, 14a, 14b Base material 15, 15a, 15b Specified visible light absorbing part 16 Absorbing member 17 Reflecting member 101a, 101b Infrared light 102, 102a, 102b, 102c, 102d Visible light 1021, 1021a 1021b Light of specific wavelength 103 Inspection light 21 Absorption reflection scattering part 22 Diffraction structure 221 Convex part 222 Concave part 23 Selective reflection part 24 Base material 25 Colored resin material layer 26 Filling part 31 Absorption reflection scattering part 33 Selective reflection film 331, 331a, 331b Concavo-convex surface 34, 34a, 34b Base material 341, 341a, 341b Concavo-convex surface 342, 342a, 342b Concavo-convex structure 343 Lens part 345 Ridge line 35, 35a, 35b Colored resin material layer 35'Colored resin material 351, 351a, 351b Concavo-convex surface 352, 352a, 352b Concavo-convex structure 353 Emission interface 36 Substrate 41, 51, 61 Absorption / reflection / scattering part 43 Cholesteric phase liquid crystal layer 431, 431a, 431b Concavo-convex surface 44, 44a, 44b, 54, 64, 74 Substrate 441a Concavo-convex surface 45, 45b, 55, 65 Colored resin material layer 451, 451a, 451b Concavo-convex surface 452, 452a, 452b Concavo-convex structure 43, 53 Cholesteric phase liquid crystal layer 46 Second selective reflection part 63, 73 Selective reflection part 62 Fine particle-containing resin layer 76 Scatter absorption resin layer 91 Infrared transmission black printing layer

Claims (14)

Light in at least a part of the wavelength band in the visible region, which reflects and scatters light of a specific wavelength corresponding to a specific color, absorbs light other than the specific wavelength, and has at least a part of the wavelength band in the infrared region. Equipped with an absorption / reflection / scattering unit that transmits light
The straight transmittance for light in at least a part of the wavelength band in the infrared region is 75% or more, and the transmittance is 75% or more.
When visible light is incident, it is observed to be colored in the specific color.
The absorption / reflection / scattering unit is
A selective reflector that reflects light in the visible region and transmits light in at least a part of the wavelength band in the infrared region.
The scattering part that scatters the light in the visible region and
It includes a specific visible light absorber that absorbs light other than the specific wavelength in the visible region.
With respect to the selective reflection unit, the scattering unit and the specific visible light absorbing unit are on the incident side or the emitting side of infrared light and on one of the predetermined sides on which visible light is incident. When viewed from the side of 1, the specific visible light absorption unit, the scattering unit, and the selective reflection unit are provided in this order.
An optical member characterized by this. The scattering portion is an uneven surface formed on the first side surface of the selective reflection portion.
The specific visible light absorbing portion is a colored resin layer which is a resin layer containing a coloring material and is laminated on the uneven surface.
The surface of the specific visible light absorbing portion on the side in contact with the scattering portion is an uneven surface having a shape that fits with the uneven surface of the selective reflection portion, and the surface on the opposite side is flat.
Refractive index of the colored resin layer and the base material in contact with the second side surface which is the other side of the first side of the selective reflection portion in at least a part of the wavelength band in the infrared region. The optical member according to claim 1 , wherein the members substantially match. The scattering portion is an uneven surface formed on the first side surface of the selective reflection portion.
The specific visible light absorbing portion is a colored resin layer which is a resin layer containing a coloring material and is arranged on a first base material laminated on the uneven surface.
The surface of the first base material on the side in contact with the scattering portion is an uneven surface having a shape that fits with the uneven surface of the selective reflection portion, and the surface on the opposite side thereof is flat.
At least a part of the infrared region of the first substrate and the second substrate in contact with the second side surface which is the other side of the selective reflection portion with respect to the first side. The optical member according to claim 1 , wherein the refractive indexes in the wavelength band are substantially the same. The scattering portion has a diffraction structure that diffracts light in at least a part of the wavelength band in the visible region.
The specific visible light absorbing portion is a colored resin layer which is a resin layer containing a coloring material.
The colored resin layer is arranged so as to at least fill the recesses of the diffraction structure, or is laminated on a first substrate arranged so as to at least fill the recesses.
The optical member according to claim 1. The selective reflection unit is one or more cholesteric phase liquid crystal layers in which the selective reflection band is set in the visible region.
The scattering portion is an uneven surface formed on the surface of the cholesteric phase liquid crystal layer located on the uppermost layer when the first side is the upper layer.
The specific visible light absorbing portion is a colored resin layer which is a resin layer containing a coloring material.
The colored resin layer is arranged so as to at least fill the concave portions of the uneven surface of the cholesteric phase liquid crystal layer, or is laminated on a first substrate arranged so as to at least fill the concave portions.
The optical member according to claim 1. The absorption reflection scattering unit is one or a plurality of cholesteric phase liquid crystals having a selective reflection band set in the visible region and having a plurality of regions having different orientation axes in the plane as the selective reflection unit and the scattering unit. Including layers
The specific visible light absorbing portion is a colored resin layer which is a resin layer containing a coloring material.
The colored resin layer is arranged at least on the first side of the cholesteric phase liquid crystal layer located on the uppermost layer when the first side is the upper layer.
The optical member according to claim 1. The selective reflection unit is a dielectric multilayer film that reflects light in the visible region and transmits light in at least a part of the wavelength band in the infrared region.
The optical member according to any one of claims 2 to 4. The coloring material is at least one of a dye dissolved in the resin material and an organic pigment dispersed in the resin material.
The optical member according to any one of claims 2 to 7. The median diameter of the organic pigment is 500 nm or less.
The optical member according to claim 8. The ratio of the coloring material in the resin material is 1% by weight to 20% by weight.
The optical member according to claim 8 or 9. The thickness of the colored resin layer is 10 μm or more and 50 μm or less.
The optical member according to any one of claims 2 to 10. The scattering unit and the specific visible light absorbing unit are specified with respect to the selective reflection unit when viewed from the first side and the second side which is the other side of the first side. The optical member according to any one of claims 1 to 11 , which is provided in the order of a visible light absorption unit, a scattering unit, and a selective reflection unit. The optical member according to any one of claims 1 to 12 , wherein the visible region is 400 nm to 750 nm, and the infrared region is 800 nm to 1000 nm. A light emitting part that emits light in a part of the wavelength band in the infrared region, or a light receiving part that receives light in a part of the wavelength band in the infrared region.
A housing that surrounds the light emitting part or the light receiving part,
It is provided with an infrared light transmission filter provided in the opening of the housing.
An optical device according to claim 1, wherein the infrared light transmission filter is the optical member according to any one of claims 1 to 13 .

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