JPH11212034A - Optical element and light control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element showing a high light response (transmission factor change, reflection factor change or light direction change) with low density power by laminating an organic pigment layer, which senses the light of a specified wavelength and reversibly changes a refraction factor for the light of different wavelengths, and a reflection layer. SOLUTION: This element is constituted by laminating the organic pigment layer, which senses the light of the specified wavelength and reversibly changes the refraction factor for the light of different wavelengths, and the reflection layer. Concerning the optical element showing the light response of the reflection factor change, in this case, the thickness of respective films is set from the optical constants of the organic pigment layer, reflection layer and substrate so that the high reflection factor of signal light can be provided when control light is not radiated yet. Then, a reflected light intensity change occurs because of the refraction factor change with the radiation of control light and a change in the absorption spectrum of the organic pigment film. When the control light is not radiated yet, it is preferable for such an optical element to provide the high reflection factor concerning signal light and to reduce the exhaustion coefficient of the organic pigment film with respect to a signal light wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical element and a light control method useful in the fields of electronics and optical photonics such as optical communication and optical information processing.

[0002]

2. Description of the Related Art In the field of optoelectronics and photonics for the purpose of transmitting and processing information at an ultra-high speed, a change in transmittance caused by irradiating an optical element formed by processing an optical material or an optical composition with light. Research and development of light and light control methods (light control methods using light) that attempt to modulate light intensity and wavelength without using electronic circuit technology by using the refractive index or refractive index change are being actively pursued. .
Phenomena expected to be applied to light / light control methods include saturable absorption, nonlinear refraction, photorefractive effects,
Phenomena such as induced absorption are attracting attention.

There are many optical materials and light control methods that have been proposed so far. Some of them are as follows. (1) JP-A-53-137883: A mixed system of a porphyrin derivative and an electron acceptor is irradiated with at least two types of light having different wavelengths, and light information of one wavelength is converted into the other light. . (2) JP-A-55-10
No. 0503: A functional liquid core type optical fiber that utilizes a spectral difference between a ground state and an excited state of a porphyrin derivative or the like and selects propagating light in response to a special change in the excitation light. (3) JP-A-63-89805: An optical fiber containing a porphyrin derivative or the like having an absorption corresponding to a transition from a triplet state excited by light to a higher triplet state in a core. (4) JP 6
No. 3-236013: Cyanine dyes having different wavelengths 2
The light of the first wavelength is irradiated, and the transmission or reflection of the light of the second wavelength is switched according to the state of light excitation by the light of the first wavelength. (5) JP-A-64-73326:
A light modulation medium in which a photoinduced electron transfer material is dispersed in a matrix is irradiated with light of first and second wavelengths, and light is modulated by an absorption spectrum difference between a ground state and an excited state.
(6) JP-A-8-320536: A polymethylene dye is irradiated with light having first and second wavelengths, and light is modulated by a difference in absorption spectrum between a ground state and an excited state.

However, these proposed prior arts require a very high-density optical power to cause a practically large change in transmittance or refractive index, or have a slow response to light irradiation. At present, it has not been put to practical use.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art and to provide an optical element which exhibits a large optical response (change in transmittance, change in reflectance, change in light direction) with low density optical power. And a light control method for the optical element.

[0006]

Means for Solving the Problems The present inventors have proposed an optical element,
As a result of studying the light control method, the laminated optical element consisting of the organic dye layer and the reflective layer or the dielectric layer was used as the control light with light of the wavelength absorbed by the organic dye, and the maximum refractive index of the organic dye was adjusted. The light near the absorption long wavelength end wavelength is given as the signal light, and the change in the refractive index due to the change in the absorbance due to the irradiation of the control light is detected as the change in the refractive index as the change in the reflectance and the transmittance. Response (transmittance change,
The present invention has been found that an optical element exhibiting a change in reflectance and a change in light direction) and a light control method therefor are possible.

According to the present invention, first, an organic dye layer which is sensitive to light of a specific wavelength and reversibly changes the refractive index with light of a different wavelength and a reflective layer are laminated. An optical element is provided. Secondly, there is provided an optical element according to the first optical element, wherein the thickness of the organic dye layer is set so as to satisfy the maximum reflectance condition at the wavelength of the signal light.

Third, light having a wavelength sensitive to the first or second optical element is used as control light, and light having a different wavelength is used as signal light. There is provided a light control method for an optical element, wherein a reflectance is reversibly changed. Fourth, in the third light control method, the wavelength of the control light sensitive to the optical element is the maximum absorption wavelength of the organic dye layer, and the wavelength of the signal light is the organic dye at the long wavelength end of the absorption spectrum of the organic dye layer. There is provided an optical element light control method, which is near the wavelength giving the maximum refractive index of the layer.

Fifth, an organic dye layer that is sensitive to light of a specific wavelength and reversibly changes the refractive index at light of a different wavelength;
An optical element characterized by being laminated with a dielectric layer is provided. Sixth, there is provided an optical element according to the above-mentioned fifth optical element, wherein the thickness of the organic dye layer is set so as to satisfy the maximum transmittance condition at the wavelength of the signal light.

Seventh, light having a wavelength sensitive to the fifth or sixth optical element is used as control light, and light having a different wavelength is used as signal light. There is provided a light control method for an optical element, wherein a transmittance is reversibly changed. Eighth, in the seventh light control method, the wavelength of the control light sensitive to the optical element is the maximum absorption wavelength of the organic dye layer, and the wavelength of the signal light is the organic dye at the long wavelength end of the absorption spectrum of the organic dye layer. There is provided a light control method for an optical element, wherein the wavelength is around a wavelength giving a maximum refractive index of a layer.

Ninth, in the first, second, fifth or sixth optical element, there is provided an optical element characterized in that the organic dye layer is made of a thermochromic material and a change in absorbance is used. You. Tenthly, in the first, second, fifth or sixth optical element, there is provided an optical element characterized in that the organic dye layer is made of a photochromic material and the change in absorbance is used. Eleventh, the first, second, fifth or sixth optical element, wherein the organic dye layer is made of an associative dye, an optical element characterized by utilizing a change in absorbance due to a change in the association state Provided. Twelfth, in the first, second, fifth or sixth optical element, the organic dye layer comprises a dye and a polymer material,
An optical element characterized by utilizing a change in absorbance due to a change in the dispersion state is provided.

Thirteenth, in the third, fourth, seventh or eighth light control method, the optical element is returned to the initial state by irradiating the organic dye layer with light under different light irradiation conditions than the control light. A light control method for an optical element is provided. Fourteenth, in the third, fourth, seventh or eighth light control method, the optical element is returned to the initial state by performing a heat treatment on the organic dye layer under heating conditions different from the control light. A light control method for an optical element is provided.

According to the present invention, it is possible to provide an optical element and a light control method which exhibit a large optical response (change in transmittance, change in reflectance, change in light direction) with low-density optical power. The biggest factor of this large optical response is that the organic dye is used as a material to change the optical constant, and furthermore, the long wavelength end of the absorption spectrum of the organic dye is used as the signal light. It has caused a large change in the refractive index.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. 1A and 1B show an optical element structure showing a light response of a change in reflectance. FIG. 1A shows a structure in which light irradiation is performed from the organic dye layer side, and FIG. 1B shows a structure in which light irradiation is performed from the substrate side. Type. FIG. 2 shows an optical element structure showing a light response of a change in transmittance and a change in light direction. FIG. 2 (A) shows a structure in which light is irradiated from the organic dye layer and the substrate side, and FIG. Is of a type that irradiates light from the substrate side. In these drawings, 1 is a substrate, 2 is an organic dye layer, 3 is a reflective layer, and 4 is a derivative layer.

The light control method of the optical element will be described with reference to FIG.
Although FIG. 3 uses the structure of FIG. 1B, FIG.
In the case of (A), the same applies if control light irradiation and signal light detection are performed from the organic dye layer side. FIG. 3A is a basic conceptual diagram in which control light is emitted from a substrate and detected as a change in the reflectance of signal light. The reflectivity R, transmittance T, and absorptance A of the multi-layer structure film are shown in F. W. According to Spong, it can be obtained as follows. When the light energy incident on the recording film is 1, the balance is given by T + A + R = 1. That is, a model (FIG. 7) for calculating the reflection, absorption, and transmission and the mathematical expressions shown in Table 1 are given.

[0016]

[Table 1]

The optical element according to the present invention, which exhibits a light response of a change in reflectance, comprises a laminate of an organic dye layer and a reflective layer, and has an organic dye layer so that signal light has a high reflectance when control light is not irradiated.
Each film thickness is set using the above calculation from the optical constants of the reflective layer and the substrate (FIG. 3B). In the light control method, a reflected light intensity change is caused by a change in refractive index accompanying irradiation of control light to change an absorption spectrum of the organic dye film (FIG. 3).
(C)). In the optical element having this configuration, when the control light is not irradiated, it is preferable to obtain a high reflectance for the signal light, and it is preferable that the extinction coefficient of the organic dye film with respect to the signal light wavelength is small (multiple reflection condition). In order to obtain a large change in reflectance, it is preferable that the absorption spectrum is changed by the control light and the change in refractive index accompanying the change is large. Organic dyes generate large electron polarization due to their light absorption, and can obtain a high refractive index. What is characteristic is its wavelength dependence, and the maximum refractive index at the long wavelength end of the absorption spectrum is obtained from the Kramers-Kronig relational expression. This is a favorable characteristic for the optical element.

That is, by setting the wavelength of the signal light at the long wavelength end of the absorption spectrum, a high extinction coefficient and a high reflectance (multiple reflection condition) are obtained. A large change in the refractive index can be obtained with a change in the absorption spectrum due to irradiation (FIG. 5 shows the relationship between the absorption spectrum of the organic dye and the wavelengths of the control light and the signal light).

FIG. 6 shows a change in the absorption spectrum and a change in the refractive index thereof before and after irradiation with light having a wavelength of 640 nm as control light using a spiropyran derivative (film thickness 900 °) as an organic dye. Here, the solid line represents the absorbance, and the dashed line represents the refractive index. It shows that a high refractive index is obtained at the signal light wavelength when the control light is not irradiated, and the refractive index decreases after the control light is irradiated. By interposing this organic dye film between a substrate (for example, a quartz plate) and a reflective layer (for example, a metal), this refractive index difference is detected as a change in the reflectance of the signal light in accordance with the above calculation with the light having a wavelength of 780 nm as the signal light. You. The control light can be used in principle in a wavelength range where the organic dye causes an absorption spectrum change, but the maximum absorption wavelength range is most preferable. This change in the absorption spectrum can be restored under light irradiation conditions (wavelength, irradiation slow cooling conditions, etc.) or heating conditions different from the control light, and reversible light control becomes possible.

FIG. 4 shows a light control method for an optical element showing the optical response of a change in transmittance and a change in light direction according to the present invention.
Here, FIG. 4 uses the structure of FIG.
The case of (B) is completely the same. FIG. 4A is a basic conceptual diagram in which the control light is emitted from the substrate and detected as a change in the transmittance of the signal light and a change in the light direction. The optical element of this type of the present invention is composed of a laminate of an organic dye layer and a dielectric layer, and the organic dye layer, the reflective layer, and the optical constant of the substrate are adjusted so that the signal light has a low transmittance when the control light is not irradiated. Each film thickness is set using the calculation (FIG. 4B). The light control method involves irradiating control light to change the absorption spectrum of the organic dye film to cause a change in the transmitted light intensity due to a change in the refractive index (FIG. 4C), or a total reflection condition and a light direction. It is characterized by causing a change (FIG. 4D). In the optical element having this configuration, when the control light is not irradiated, it is preferable to obtain a high reflectance with respect to the signal light, and it is preferable that the organic dye film has a small extinction coefficient with respect to the signal light wavelength.

In order to obtain a large change in transmittance and a condition of total reflection, it is preferable that 1) the absorption spectrum is changed by the same control light, and the change in refractive index accompanying the change is large. Accordingly, a similar relationship between the absorption spectrum, the control light, and the signal light is obtained. By further providing the organic dye film of FIG. 6 on a derivative layer (for example, a polycarbonate resin) provided on a substrate (for example, a quartz plate), 640 n of control light is provided.
Assuming that m is 780 nm as the signal light, the refractive index difference is detected as a change in the refractive index and a change in the light direction (total reflection condition) of the signal light according to the above calculation. In the light control method in which the light direction is changed as the total reflection condition, each film thickness is calculated from the optical constants of the organic dye layer, the reflection layer, and the substrate so that the signal light becomes the total reflection condition after irradiation with the control light. It is preferable to set.

As described above, the structure of the optical element of the present invention includes a structure for obtaining an optical response of a change in reflectance shown in FIG. 1 and a structure for obtaining an optical response of a change in refractive index and light direction shown in FIG. Is also good. If necessary, a protective layer and a reinforcing layer may be provided.

The substrate must be transparent to control light and signal light only when control light irradiation and signal processing detection are performed from the substrate side.
The substrate need not be transparent when performing signal detection.
As the substrate material, for example, plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, and polyimide, glass, ceramic, or metal can be used.

The characteristics required for the organic dye layer (recording layer) include that the spectral characteristics of the signal light wavelength change due to the influence (light and heat) of the control light irradiation, and that the refractive index also changes. It is. In the light control method for obtaining a more reversible light response, it is necessary to return to the initial state (spectral characteristics, refractive index) under other light irradiation conditions or heating conditions. The following are suitable material systems. (1) Photochromic material: A material that utilizes a change in optical characteristics due to light. (2) Thermochromic material: A material that utilizes a change in optical properties due to heat. (3) Associative dye: A dye that utilizes a change in optical properties due to a change in the association state of the dye. (4) Dye / polymer composite material: A material utilizing a change in optical properties due to a change in the dispersion state of the dye.

Specific examples of these materials include (1) photochromic materials utilizing photoisomerization reaction, photoreduction or closure reaction, photodissociation reaction, photooxidation-reduction reaction,
For example, spiropyran derivatives, azobenzene derivatives, fulgide derivatives, diallylethene derivatives, spirooxazine derivatives and the like can be used. As the above (2), liquid crystals, conductive polymers, thermochromic materials utilizing a redox reaction, such as thermochromic inks, etc. As the above (3), azaannulene dye, cyanine dye, perylene dye,
Phenazine dyes, phenothiazine dyes, and the like can be used. As (4), a complex system in which the compatibility between the dye and the polymer material is changed by heat or light, for example, the dye material of (3) and a polymer material such as an acrylic resin Is available.

Examples of the polymer material include acrylic resin, polycarbonate resin, polyester resin, polyether resin, styrene resin, butyral resin, polyether sulfone resin, urethane resin, polysulfone resin, butadiene resin, polyacetal resin, ionomer resin, Polyamide resin, vinyl resin, natural polymer,
Examples include polymers and copolymers such as silicone and liquid rubber.

The recording layer may be mixed or laminated with other organic dyes, metals and metal compounds for the purpose of improving optical characteristics, recording sensitivity, signal characteristics and the like. Organic dyes include polymethylene dyes, naphthalocyanine, phthalocyanine, squarylium, croconium, pyrylium, naphthoquinone, anthraquinone (indanthrene), xanthene, triphenylmethane, azulene, and tetrahydrocholine. , Phenanthrene,
Examples include a triphenothiazine dye and a metal complex compound.

The recording layer may further contain a stabilizer (eg, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer which are commonly used in this technical field for the purpose of improving properties. Etc. can be used together.

The recording layer can be formed by ordinary means such as vapor deposition, sputtering, CVD or solvent coating. When the coating method is used, the above-mentioned dye or the like can be dissolved in an organic solvent, and the coating can be performed by a conventional coating method such as spraying, roller coating, diving, and spin coating. As the organic solvent to be used, generally, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and N, N-
Amides such as dimethylformamide and N, N-dimethylacetamide; sulfoxides such as dimethylsulfoxide; ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; chloroform; Methylene, dichloroethane, carbon tetrachloride,
Aliphatic halogenated hydrocarbons such as trichloroethane, aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene, cellosolves such as methoxyethanol and ethoxyethanol, and hydrocarbons such as hexane, pentane, cyclohexane, methylcyclohexane, etc. Is mentioned. The film thickness of the recording layer is 100 to 1 μm, preferably 200 to 2000 °.

Examples of the material for the reflective layer include metals, semimetals, organic dyes, etc., which are hardly corroded and provide high reflectivity.
Examples of metal materials include Au, Ag, Cr, Ni, Al, and F.
e, Sn and the like.
u, Ag, and Al are most preferred. These metals and metalloids may be used alone or as two kinds of alloys. Examples of the film forming method include vapor deposition and sputtering.
The film thickness is 50-5000 °, preferably 100-3.
000. As the dye, the materials described in the material examples of the organic dye layer can be used, and the film forming method and the film thickness are also the same.

As the dielectric material, any material may be used as long as it is transparent to control light and signal light, and organic materials and inorganic materials can be used. Examples of the organic material include the above-mentioned polymer materials, and further, a low-molecular-weight organic material may be mixed and dispersed in order to control the optical constant, and examples of the inorganic material include magnesium fluoride and calcium fluoride. Examples thereof include alkali earth halide compounds, alkali metal halide compounds, semimetals such as silicon monoxide and silicon dioxide, and metal oxides.

The protective layer and the hard coat layer on the substrate surface protect the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc.
It is used for the purpose of improving the storage stability of the recording layer (reflection / absorption layer), improving the reflectance, and the like. For these purposes, the following materials for the undercoat layer can be used. An inorganic or organic material can be used for the undercoat layer. As the inorganic material, silicon monoxide, silicon dioxide and the like can also be used, and as the organic material, polymethyl acrylate resin, polycarbonate resin, epoxy resin, polystyrene resin, polyester resin, vinyl resin, cellulose,
Thermosoftening and heat melting resins such as aliphatic hydrocarbon resins, natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil, and rosin can also be used. The most preferable example of the above materials is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is suitably 0.01 to 30 μm, preferably 0.05 to 10 μm. In the present invention, the undercoat layer, the protective layer, and the substrate-side hard coat layer have a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, and a plasticizer as in the case of the recording layer. Etc. can be contained.

[0033]

Next, the present invention will be described more specifically with reference to examples.

Example 1 A chloroform solution of a benzopyran compound of the following structural formula (I) was spin-coated on a 1.0 mm-thick quartz plate to form an organic dye layer having a thickness of 1500 °, and then formed by sputtering. A reflective layer of 1500 ° is provided, and a protective layer of 5 μm is further provided thereon with an acrylic photopolymer,
It was an optical element. Its vertical reflectance at a wavelength of 780 nm was 71%. This optical element has a wavelength of 620
Irradiation was performed so that the absorption spectrum was sufficiently changed, and then the reflectance in the vertical direction at a wavelength of 780 nm was measured in the same manner to be 49%. Further, after this optical element was irradiated with light having a wavelength of 330 nm or heated at 120 ° C., the reflectance in the vertical direction at a wavelength of 780 nm was measured again and found to be 69%. As a result, by using a wavelength of 620 nm (input of a signal) and a wavelength of 330 nm (input of a signal) as control light and a wavelength of 780 (input of a signal) as signal light, a large optical response (change in reflectance) can be obtained. It was confirmed that the method was an optical element using an organic dye layer and a light control method thereof.

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Example 2 A phthalocyanine compound of the following structural formula (II) and Poly (Sodium 4-sty) were placed on a quartz plate having a thickness of 1.0 mm.
A chloroform solution of a mixture of rensulfonate (weight ratio 1/1) was applied by spinner coating to a film thickness of 1400Å.
Is formed, and then gold 1 is formed by sputtering.
An optical element was formed by providing a reflective layer having a thickness of 500 ° and further providing a protective layer of 5 μm using an acrylic photopolymer thereon. Its vertical reflectance at a wavelength of 790 nm is 6
8%. The optical element was irradiated with light having a wavelength of 680 nm so that its absorption spectrum was sufficiently changed, and then the reflectance in the vertical direction at a wavelength of 790 nm was measured. Further, this optical element is set to a wavelength of 7
After irradiation with light of 70 nm or heating at 150 ° C., the reflectance in the vertical direction at a wavelength of 790 nm was measured again and found to be 67%. Accordingly, a dye having a large optical response (change in reflectance) can be obtained by using a wavelength of 680 nm (signal input) and a wavelength of 740 nm (signal erase) as control light and a wavelength of 790 (signal input) as signal light. It was confirmed that the optical element was made of a molecular material and used an organic dye layer utilizing the change in absorbance due to the change in the dispersion state, and the light control method thereof.

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Example 3 A 1 μm-thick dielectric layer was formed by spin-coating a chloroform solution of a polycarbonate resin on a 1.0 mm-thick quartz plate, and a benzothiopyran compound of the following structural formula (III) was further formed thereon. A 1,1,2-trifluoro alcohol solution was applied by spinner to form an organic dye layer having a thickness of 900 °, thereby obtaining an optical element. Its vertical transmittance at a wavelength of 830 nm was 55%. The optical element was irradiated with light having a wavelength of 680 nm so that its absorption spectrum was sufficiently changed, and then the reflectance in the vertical direction at a wavelength of 830 nm was measured to be 87%. Further, the optical element is irradiated with light having a wavelength of 420 nm, or
After heating at ° C., the reflectance in the vertical direction at a wavelength of 830 nm was measured again and found to be 58%. Thus, the wavelength of the control light is 680 nm (signal input),
A wavelength of 420 nm (signal erasure) is set to 830 as signal light.
An optical element using an organic dye layer made of a dye and a polymer material that can provide a large optical response (change in reflectance) by using (signal input) and utilizing the change in absorbance due to the change in the dispersion state, and its light control It was confirmed that it was a law.

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Example 4 A 1,1,2-trifluoroalcohol solution of a benzothiopyran compound of the same structural formula (IV) as in Example 3 was spin-coated on a 1.0 mm-thick quartz plate by spinner coating.
An organic dye layer was formed, and a hexane solution of a petroleum resin was spin-coated thereon to form a 1 μm-thick dielectric layer, thereby forming an optical element. Incident angle 4 at wavelength 830 nm
The reflectance in the 0-degree direction was 6%, and the transmittance was 90% or more. After irradiating light having a wavelength of 680 nm to such an extent that its absorption spectrum is sufficiently changed, the reflectivity was similarly measured in the direction of an incident angle of 40 degrees at a wavelength of 830 nm. Was. Similarly, after irradiation with light having a wavelength of 420 nm or heating at 120 ° C., the reflection in the oblique 45 ° direction at a wavelength of 830 nm was measured again and found to be 13%. As a result, a wavelength of 680 nm (input of a signal) and a wavelength of 420 nm (erasing of a signal) are used as control light and 830 nm as a signal light.
It was confirmed that an optical element using a photochromic organic dye layer capable of obtaining a large optical response (light direction change) by using (signal input) and a light control method thereof.

[0038]

According to the first aspect of the present invention, it is possible to provide a basic structure and a material configuration as an optical element exhibiting a large optical response (change in reflectance). According to the second aspect of the present invention, it is possible to provide the optimum configuration condition of the optical element that obtains the largest optical response. According to the third aspect of the present invention, a light control method that obtains a large light response by using the optical element can be obtained. According to the fourth aspect of the present invention, an optimal configuration / control method of a light control method for obtaining the largest light response is possible. According to the fifth aspect of the present invention, it is possible to provide a basic structure and a material configuration as an optical element exhibiting another large optical response (change in transmittance, change in light direction). According to the sixth aspect of the present invention, it is possible to provide the optimum configuration condition of the optical element that obtains the largest optical response. According to the seventh aspect of the present invention, it is possible to provide a light control method for obtaining a large light response by using this optical element. According to the invention of claim 8, an optimal configuration / control method of the light control method for obtaining the largest light response is possible. According to the ninth, tenth, eleventh, and twelfth aspects of the present invention, it is possible to provide an optical element exhibiting a larger optical response with an optimum constituent material for the optical element. According to the invention of claims 13 and 14, reversible optical response is possible.

[Brief description of the drawings]

FIG. 1A is a diagram showing an optical element structure showing an optical response of a change in reflectance, and FIG. 1B is a diagram showing another optical element structure showing an optical response of a change in reflectance.

FIG. 2A is a diagram showing an optical element structure showing a light response of a change in transmittance and light direction, and FIG. 2B is another diagram showing an optical response of a change in light transmittance and light direction. The figure showing the optical element structure.

3A is a diagram showing a light control method using an optical element showing an optical response of a change in reflectance, and FIG. 3B is a diagram showing signal light (reflection) of an optical element before irradiation with control light; FIG. 3C is a diagram showing signal light (reflectance) intensity of the optical element after irradiation with control light.

FIG. 4A is a diagram showing a light control method using an optical element showing a light response of a change in transmittance and a change in a light direction;
(B) shows signal light (transmittance, optical signal) of the optical element before irradiation with control light.
FIG. 4C is a diagram showing signal light (transmittance, reflectance) intensity of the optical element after irradiation with control light, and FIG. 4D is a diagram showing intensity after control light irradiation. FIG. 5 is a diagram showing signal light (reflectance) intensity / light direction change of the optical element of FIG.

FIG. 5 is a diagram showing the relationship between the absorption spectrum of an organic dye, control light, signal light, and wavelength.

FIG. 6 is a diagram showing a change in an absorption spectrum of an organic dye and a change in an optical constant thereof caused by control light.

FIG. 7 is a model diagram for calculating the reflectance, the transmittance, and the absorptance of the multilayer structure film.

[Explanation of symbols]

 11 Substrate 22 Organic dye layer 33 Reflective layer 44 Dielectric layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasunobu Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Stock inside Ricoh Company (72) Inventor Yasuhiro Higashi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Inside the company Ricoh

Claims (14)

[Claims] 1. An optical element comprising an organic dye layer which is sensitive to light of a specific wavelength and reversibly changes the refractive index of light of a different wavelength and a reflective layer. 2. The optical element according to claim 1, wherein the thickness of the organic dye layer is set so as to satisfy the maximum reflectance condition at the wavelength of the signal light. 3. The reflectance of the signal light by irradiating the control light with light of a wavelength to which the optical element according to claim 1 is sensitive as control light and light of a different wavelength as signal light. A light control method for an optical element, characterized by reversibly changing. 4. The wavelength of the control light to which the optical element is sensitive is defined as the maximum absorption wavelength of the organic dye layer, and the wavelength of the signal light is the wavelength giving the maximum refractive index of the organic dye layer at the long wavelength end of the absorption spectrum of the organic dye layer. 4. The optical element light control method according to claim 3, wherein the optical element is located near the optical element. 5. An optical element comprising an organic dye layer responsive to light of a specific wavelength and reversibly changing the refractive index of light of a different wavelength, and a dielectric layer. 6. The optical element according to claim 5, wherein the thickness of the organic dye layer is set so as to satisfy a maximum transmittance condition at the wavelength of the signal light. 7. The optical element according to claim 5, wherein light having a wavelength sensitive to the optical element is used as control light, and light having a different wavelength is used as signal light, and the control light is irradiated on the optical element to transmit the signal light. A light control method for an optical element, characterized by reversibly changing. 8. The wavelength of the control light to which the optical element is sensitive is defined as the maximum absorption wavelength of the organic dye layer, and the wavelength of the signal light is the wavelength that gives the maximum refractive index of the organic dye layer at the long wavelength end of the absorption spectrum of the organic dye layer. 8. The light control method for an optical element according to claim 7, wherein the distance is set near. 9. The optical element according to claim 1, wherein the organic dye layer is made of a thermochromic material, and a change in absorbance is used. 10. The optical element according to claim 1, wherein the organic dye layer is made of a photochromic material, and a change in absorbance is used. 11. The optical element according to claim 1, wherein the organic dye layer is made of an associative dye, and utilizes a change in absorbance due to a change in the association state. 12. The optical element according to claim 1, wherein the organic dye layer comprises a dye and a polymer material,
An optical element utilizing a change in absorbance due to a change in the dispersion state. 13. The light control method according to claim 3, wherein the optical element is returned to an initial state by irradiating the organic dye layer with light under different light irradiation conditions from the control light. Light control method for optical element. 14. The optical control method according to claim 3, wherein the optical element is returned to an initial state by subjecting the organic dye layer to a heat treatment under a heating condition different from that of the control light. Light control method of the element.