JP4045870B2 - Optical element manufacturing method, electrodeposition liquid used therefor, and optical element manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polymer thin film patterned on the order of μm, and in particular, production of an optical element having a distribution in color, refractive index, etc. in the plane of the thin film or in the film thickness direction of the thin film. Regarding the method.
[0002]
[Prior art]
Conventionally, as a method of patterning a polymer thin film on the order of μm, a photocurable resin as a polymer thin film material is applied and dried on a flat substrate by means such as spin coating, exposed to ultraviolet light, and then developed. A method of patterning is known. In addition, when the polymer thin film material is not a photocurable resin, a method of patterning by further applying a photocurable resin on the polymer film material in the same manner, and exposing and developing is also known.
In these methods, a functional material having a certain function in a polymer thin film, for example, fine particles (pigments, high refractive materials, etc.), molecules (dyes, etc.), or another kind of polymer, etc. are dispersed to form a uniform material. A dispersion film can be produced. However, since the polymer thin film itself is uniformly formed by, for example, spin coating, it is possible to have a concentration distribution within the surface of the thin film or in the thickness direction of the thin film, or to continuously change the concentration. There wasn't. It is possible to prepare a thin film with a concentration distribution in the film thickness direction by preparing multiple types of coating solutions of polymer thin film materials with different functional material concentrations and applying it several times. The concentration change is stepped and it is difficult to change the concentration continuously.
[0003]
On the other hand, the present inventors have provided an image forming method and a color filter manufacturing method excellent in resolution by using an electrodeposition material containing a colorant and performing electrodeposition or photo-deposition by applying a low voltage. These are disclosed in JP-A-10-119414, JP-A-11-189899, JP-A-11-15418, JP-A-11-174790, JP-A-11-133224, JP-A-11-335894. And the like. These image forming methods and color filter manufacturing methods are characterized by forming colored films with high resolution by a simple method, but are mainly applied in the field of display devices such as liquid crystal display devices. .
[0004]
In the photo-deposition method and related technology, one or more of (a) bias voltage intensity to be applied, (b) light irradiation time, and (c) light intensity to be applied are controlled to perform electrodeposition. By continuously changing the film thickness to be formed, the amount of the functional material contained therein can be continuously changed (that is, there are many functional materials where the film thickness is large). Therefore, by this method, a thin film having a continuous gradation of the functional material can be obtained in the plane. On the other hand, however, the flatness of the film is impaired, and when the obtained polymer thin film is transferred to another surface, problems such as easy bleeding of a portion having an excessively thick film thickness occur. Further, it is needless to say that this method cannot obtain a thin film having a continuous gradation of the functional material in the film thickness direction.
[0005]
In the conventional technology, as a technique for obtaining gradations by changing the concentration of the functional material inside the polymer thin film, a molecule whose color changes or disappears when irradiated with light of a specific wavelength is used. There is a method called a photo bleaching method. By utilizing this method, a certain degree of refractive index distribution can be obtained even within a uniform layer such as a spin coat film. However, since the materials suitable for the photo bleaching method are limited, the degree of freedom of the technique is low and it is not general.
[0006]
In this way, any functional material (pigment fine particles, dyes, high refractive material fine particles, etc.) is contained inside the thin film whose main component is a polymer material, and it is continuous in the thin film plane or in the film thickness direction of the thin film. A method for producing a polymer thin film having a proper concentration distribution (gradation) and a method for producing a patterned polymer thin film as described above have not been realized.
[0007]
[Problems to be solved by the invention]
The present invention has been made on the basis of the above-mentioned demands, and its object is to provide a gentle or continuous functional material in the thin film plane of the polymer thin film containing the functional material and / or in the film thickness direction of the thin film. It is an object of the present invention to provide a method for manufacturing an optical element that can easily provide a typical concentration distribution (gradation), an electrodeposition liquid for use in the method, and an optical element manufacturing apparatus.
[0008]
[Means for Solving the Problems]
  The subject of the present invention is the following optical element manufacturing methodLawAnd an optical element manufacturing apparatus.
(1) An optical element manufacturing substrate in which a conductive thin film is provided on an insulating substrate is a water-based material containing a film-forming polymer material and a functional material whose solubility or dispersibility in aqueous liquids is lowered by changing pH. A voltage is applied to the electrodeposition liquid between the conductive thin film and the counter electrode in a state where at least the conductive thin film of the optical element fabrication substrate is in contact with the electrodeposition liquid. An optical element manufacturing method comprising a step of depositing and forming a thin film containing the film-forming polymer material and the functional material on the top,In the electrodeposition liquid, an electrodeposition liquid having a functional material concentration different from the functional material concentration of the electrodeposition liquid is caused to flow toward the optical element manufacturing substrate at a rate of 0.1 to 10 mm / second,An optical element manufacturing method including a step of changing a concentration of a functional material in an electrodeposition liquid in the vicinity of an optical element manufacturing substrate to form a thin film in which the functional material contained therein has a density gradation.
[0009]
(2) Film-forming polymer material and function in which an optical element manufacturing substrate in which a conductive thin film and an optical semiconductor thin film are laminated in this order on an insulating substrate is reduced in solubility or dispersibility in aqueous liquid due to pH change By irradiating a selected region of the optical semiconductor thin film with light in an aqueous electrodeposition liquid containing a conductive material in a state where at least the optical semiconductor thin film of the optical element fabrication substrate is in contact with the electrodeposition liquid A voltage is applied between the optical semiconductor thin film and the counter electrode in the selected region, and the selected region of the semiconductor thin film isFilm-forming polymerMaterial andFunctional materialsAn optical element manufacturing method including a step of forming a precipitate,In the electrodeposition liquid, an electrodeposition liquid having a functional material concentration different from the functional material concentration of the electrodeposition liquid is caused to flow toward the optical element manufacturing substrate at a rate of 0.1 to 10 mm / second,An optical element manufacturing method including a step of changing a concentration of a functional material in an electrodeposition liquid in the vicinity of an optical element manufacturing substrate to form a thin film in which the functional material contained therein has a density gradation.
[0010]
(3) The method for producing an optical element according to (1) or (2), wherein the functional material contained in the thin film has a density gradation in the film thickness direction of the thin film.
(4) The method for producing an optical element according to (1) or (2), wherein the functional material contained in the thin film has a density gradation in an in-plane direction of the thin film.
(5(2) The method for producing an optical element according to (1) or (2), wherein the functional material concentration of the electrodeposition liquid that flows out toward the optical element production substrate is changed over time.
(6(1) The method for producing an optical element according to (1) or (2), wherein a step of transferring all the thin films formed on the optical element production substrate to another substrate is performed.
(7(2) The method for producing an optical element as described in (1) or (2) above, further comprising a step of heat-treating the thin film after forming the thin film.
(8(2) further comprising the step of forming a thin film on the entire surface of the substrate by applying a voltage exceeding the Schottky barrier of the optical semiconductor thin film of the optical element fabrication substrate without irradiating light. The optical element manufacturing method of description.
[0012]
(9) An optical element manufacturing apparatus for manufacturing an optical element on an optical element manufacturing substrate in which a conductive thin film and an optical semiconductor thin film are laminated in this order on an insulating substrate, and dissolving in an aqueous liquid by changing pH An electrodeposition tank for containing a water-based electrodeposition liquid containing a film-forming polymer material and a functional material that have reduced properties or dispersibility, and is placed in the electrodeposition tank and electrically connected to the conductive thin film A counter electrode, an exposure means for irradiating light to the optical semiconductor thin film of the optical element manufacturing substrate, and a film formation in which solubility or dispersibility in an aqueous liquid decreases due to pH change with respect to the optical element manufacturing substrate A water-based electrodeposition liquid having a functional material concentration different from the functional material concentration of the polymer material and the electrodeposition liquid is directed toward the optical element fabrication substrate.At a speed of 0.1 to 10 mm / secAn optical element manufacturing apparatus for manufacturing a thin film having at least a liquid flow forming mechanism for flowing out and in which a functional material contained therein has a density gradation.
(10) The optical element manufacturing apparatus according to (9), further including voltage applying means for applying a voltage between the conductive thin film and the counter electrode.
[0013]
(11) An optical element manufacturing apparatus for manufacturing an optical element on an optical element manufacturing substrate in which a conductive thin film is provided on an insulating substrate, and the solubility or dispersibility in an aqueous liquid decreases due to pH change. An electrodeposition tank for containing an aqueous electrodeposition liquid containing a film-forming polymer material and a functional material, a counter electrode placed in the electrodeposition tank and electrically connected to the conductive thin film, a conductive thin film, A voltage applying means for applying a voltage to the counter electrode, and a film-forming polymer material whose solubility or dispersibility in an aqueous liquid is lowered due to a change in pH with respect to the optical element manufacturing substrate, and the electrode Aqueous electrodeposition liquid having a functional material concentration different from the functional material concentration of the landing liquid is directed toward the optical element fabrication substrate.At a speed of 0.1 to 10 mm / secAn optical element manufacturing apparatus for manufacturing a thin film having at least a liquid flow forming mechanism for flowing out and in which a functional material contained therein has a density gradation.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is disclosed in JP-A-10-119414, JP-A-11-189899, JP-A-11-15418, JP-A-11-174790, JP-A-11-133224, JP-A-11-335894. The optical element is produced by using a technique for depositing and forming a thin film by using the electrodeposition method or the photo-deposition method described in the Gazette and the like. The concentration of the functional material in the electrodeposition liquid in the vicinity of the optical element production substrate By changing the above, a thin film in which the functional material contained therein has a density gradation is produced. In the following description, an optical waveguide (cladding layer, core layer, etc.) or a lens will be mainly described as an optical element, but the present invention is not limited to these.
According to the optical element manufacturing method of the present invention, it is possible to easily make the density gradation of the functional material in the thin film, and it is possible to obtain a continuous density gradation instead of the step-like density change as in the prior art. it can. Further, it is possible to create density gradations not only in the film thickness direction but also in the in-plane direction of the film, and further to combine these to obtain a three-dimensional density gradation. In addition, the thin film itself formed by precipitation has a uniform film thickness (film is flat) regardless of the density gradation, so that transfer is easy, and there are few bleeding and defects.
[0015]
This electrodeposition method basically uses an electrodeposition substrate in which a conductive thin film is provided on an insulating substrate, and a film-forming polymer material whose solubility or dispersibility in an aqueous liquid is lowered by changing pH. A voltage is applied between the conductive thin film and the counter electrode in a state where at least the conductive thin film is placed in contact with the electrodeposition liquid in the aqueous electrodeposition liquid containing, This is a method for precipitating the material.
In addition, the photo-deposition method uses a photovoltaic force generated in a photo-semiconductor thin film, and a photo-deposition substrate in which a conductive thin film and a photo-semiconductor thin film are laminated in this order on an insulating substrate is changed into water-based by changing pH. A selected region of the optical semiconductor thin film in a water-based electrodeposition liquid containing a film-forming polymer material whose solubility or dispersibility in a liquid is reduced, at least in a state where the optical semiconductor thin film is in contact with the electrodeposition liquid In this method, a voltage is applied between the photo-semiconductor thin film in the selected region and the counter electrode by irradiating light onto the selected region, and the material is deposited in the selected region of the semiconductor thin film.
[0016]
By using these electrodeposition and photodeposition methods, an optical element having a fine pattern can be formed with high accuracy without applying a high voltage (5 V or less). In addition, in the conventional method for producing an optical element using a photosensitive resin, it is necessary to apply a film with a precisely controlled film thickness, and there is a problem that an alkaline waste liquid is discharged by etching. Therefore, the film thickness of the thin film to be formed can be easily controlled by adjusting the light irradiation time or the voltage application time, and the etching process for pattern formation is unnecessary and the burden on the environment is small.
[0017]
First, a method for manufacturing an optical element using a photo-deposition method will be described. The optical element manufacturing substrate used in this method is obtained by laminating a conductive thin film and an optical semiconductor thin film in this order on an insulating substrate. As the insulating substrate, a glass plate, a quartz plate, a plastic film, an epoxy substrate, etc. As the conductive thin film, ITO, indium oxide, nickel, aluminum or the like is used. As the optical semiconductor thin film, a titanium oxide thin film, a zinc oxide thin film or the like as described below is used. In the case where light is applied to the optical semiconductor thin film through the insulating substrate, the insulating substrate and the conductive thin film must be light transmissive. However, this does not apply when light is irradiated through the electrodeposition solution.
The electrodeposition liquid is common to the electrodeposition method described below, and will be described later.
[0018]
In the present invention, the “selected region” may refer not only to a partial region of the optical element manufacturing substrate but also to the entire surface region. For example, when the clad layer is formed on the entire surface of the substrate, the light is applied to the entire surface. It means to irradiate.
[0019]
In the case of producing an optical element by laminating a clad layer and a core layer by the method of the present invention, and in order to form the clad layer on the entire surface, first, an electrodeposition liquid for clad formation is used. After the clad layer is formed by irradiating the selected region (entire surface) of the manufacturing substrate with light, the core forming electrodeposition solution is used to dry the clad layer without drying the formed clad layer. The core layer can be formed by irradiation. Further, a clad layer can be further formed on the core layer by irradiating the entire surface with light using the electrodeposition liquid for clad formation without drying the clad layer and the core layer thus formed. (Lower cladding layer-core layer-upper cladding layer).
Furthermore, when forming the cladding layer, it is possible to electrodeposit the cladding layer by applying a voltage exceeding the Schottky barrier of the optical semiconductor thin film of the optical element fabrication substrate without irradiating light. is there. In this method, the exposure process can be omitted, and the method becomes simpler.
[0020]
Here, an example of the optical element manufacturing method of the present invention will be described with reference to the drawings. 1A to 1D, functional materials (for example, refractive index control fine particles) have a concentration gradation in the thickness direction of the core layer, and the cladding layer is placed on the entire surface of the substrate with the core layer interposed therebetween. The manufacturing process of the formed optical waveguide is shown.
FIG. 1A shows an example of an optical element manufacturing substrate, 10 is an optical element manufacturing substrate, 12 is an insulating substrate, 14 is a conductive film, and 16 is an optical semiconductor thin film. In FIG. 1B, an electrodeposition liquid for a cladding layer is used on an optical semiconductor thin film, and the entire surface is irradiated with light, or a voltage exceeding the Schottky barrier of the optical semiconductor thin film is applied without light irradiation. It is a figure which shows the state which formed the cladding layer 18 (undried state) by.
FIG. 1C shows a state in which the core layer 20 is formed in the selected region by irradiating the selected region with light using the core layer electrodeposition liquid on the undried clad layer 18. At this time, as described later, by changing the concentration of the functional material in the electrodeposition liquid in the vicinity of the optical element manufacturing substrate, a core layer in which the functional material contained therein has a density gradation is manufactured. When the functional material is refractive index control fine particles, a core layer having a refractive index distribution is formed. In this figure, the aspect in which the intermediate part contains a lot of functional materials in the film thickness direction of the core layer is shown.
FIG. 1D shows a Schottky barrier that the photo semiconductor thin film has on the undried core layer 20 using a clad layer electrodeposition solution or with or without light irradiation. It is a figure which shows the state which formed the clad layer 22 (undried state) by applying the voltage exceeding. Thereafter, each layer is dried to obtain an optical element.
In the above example, the core layer has a density gradation, but it goes without saying that the cladding layer or the core layer and the cladding layer may have density gradation.
[0021]
2A and 2B show an example of an optical element (for example, a lens) in which the functional material contained in the thin film has a density gradation in the in-plane direction of the thin film. 2A and 2B show a state in which the concentration of the functional material decreases from the center of the circle toward the periphery in the thin film 24 having a circular planar shape formed on the optical element manufacturing substrate 10. The density is shown.
[0022]
Moreover, in the said photoelectric deposition method, what provided the optical-semiconductor thin film on the electroconductive board | substrate may be used as an optical element production substrate. As a material for the conductive substrate, at least one selected from iron and its compounds, nickel and its compounds, zinc and its compounds, copper and its compounds, titanium and its compounds, and mixed materials thereof can be used. In addition to this, a conductive plastic film can also be used as the conductive substrate.
When the optical semiconductor is titanium oxide or zinc oxide, the optical semiconductor thin film is formed on the surface of the plate by oxidizing the surface of the metal titanium or metal zinc plate in addition to the method described below. Can do. In this case, the optical element manufacturing substrate or the deposition substrate is composed of a conductive substrate and an optical semiconductor thin film thereon.
For the oxidation treatment, an inexpensive method such as high-temperature heat treatment in air or anodization treatment can be used, and a light-transmitting semiconductor thin film can be formed without using an expensive sputtering method. It should be noted that it is desirable to perform an insulating film treatment on the portion of the base metal substrate that has not been oxidized to avoid unnecessary electrodeposition film formation.
[0023]
Next, a method for producing the optical element as described above by using an electrodeposition method will be described. In this method, an optical element manufacturing substrate in which a conductive thin film or a patterned conductive thin film is provided on an insulating substrate is used, and this changes in solubility or dispersibility in aqueous liquid due to pH change. A voltage is applied between the conductive thin film and the counter electrode in an aqueous electrodeposition liquid containing a film-forming polymer material and a functional material so that at least the conductive thin film is in contact with the electrodeposition liquid. The material is deposited on the conductive thin film, and by changing the concentration of the functional material in the electrodeposition liquid in the vicinity of the optical element manufacturing substrate, the concentration of the functional material contained therein is adjusted. The thin film which has can be produced. For example, a core layer having a functional material density gradation can be formed on the optical element fabrication substrate by this method.
As the insulating substrate, the same one as in the case of the photoelectric deposition method can be used. The patterned conductive thin film is formed by patterning the conductive thin film by a conventional method, or by applying an insulating film leaving only a necessary portion on the conductive substrate and exposing the patterned conductive portion. May be used. Using these substrates, a clad layer or a core layer can be produced by an electrodeposition method.
[0024]
Next, a method for transferring the optical element formed as described above to another substrate will be described.
First, a method for transferring an optical element produced by the above-described photo-deposition method onto an optical element substrate will be described. An optical element produced by a photo-deposition method, a core layer alone or a clad layer alone, or a clad layer and a core layer can be transferred to another substrate. As this substrate, a substrate that also functions as a cladding layer can be used. By doing in this way, the total number of processes including an electrodeposition process can be reduced. However, when an optical element is formed by electrodepositing the core layer and the clad layer separately and repeating the transfer, the transfer is repeated, so the loss of the interface between the core layer and the clad layer and the waveguide shape The possibility of collapse is slightly increased.
As the optical element substrate, a commonly used glass substrate or epoxy substrate can be used, and as an optical element substrate that also functions as a cladding layer, a polyolefin film such as polyethylene, a polyester film, a polycarbonate film, an acrylic resin A film, a fluorinated polymer film, or the like can be used.
[0025]
Also, the clad layer or core layer produced by the electrodeposition method can be transferred to another substrate. At this time, it is advantageous to use a substrate having the function of a clad layer.
[0026]
When transferring an optical element produced by the above-mentioned photo-deposition method to another substrate, if a release layer is provided in advance on the optical element production substrate, it is necessary to apply large heat or pressure when transferring the optical element to the substrate. Without damaging the substrate, optical elements, and the like. The release layer preferably has a critical surface tension of 30 dyne / cm or less and does not affect the electrodeposition current. Specifically, a commercially available waterproof fluororesin spray can be used. Silicone resin or silicone oil can also be used. Furthermore, a thin film of unsaturated fatty acid such as oleic acid is also suitable.
[0027]
As a film-forming polymer material whose solubility or dispersibility in aqueous liquids is lowered by changing pH, the ion dissociation property is changed by changing the pH of the solution, such as carboxyl group and amino group. It is preferable to include a substance having a group (ionic group) in the molecule. However, the presence of an ionic group is not necessarily essential for the material. Further, the polarity of ions is not limited.
[0028]
The film-forming polymer material whose solubility or dispersibility in aqueous liquid is lowered by changing pH is a polymer material having such properties from the viewpoint of the mechanical strength of the thin film (optical element). Is preferred. Examples of such a polymer material include a polymer material having an ionic group (ionic polymer) as described above. The ionic polymer needs to have sufficient solubility or dispersibility with respect to an aqueous liquid (including an aqueous liquid whose pH is adjusted), and also needs to have optical transparency. It is.
[0029]
Further, in order to have a function of lowering solubility or dispersibility in aqueous liquid due to pH change, it is preferable that the molecule has a hydrophilic group and a hydrophobic group, and the hydrophilic group includes a carboxyl group (anionic group). ), An ionizable group (hereinafter simply referred to as “ionizable group”) such as an amino group (cationic group) is preferably introduced. For example, in the case of a polymer material having a carboxyl group, the carboxyl group becomes dissociated and dissolves in an aqueous liquid when the pH is in an alkaline region, and the dissociated state disappears and the solubility is lowered and precipitates in an acidic region.
[0030]
The presence of a hydrophobic group in the polymer material gives the polymer material the function of instantly depositing a film, in combination with the loss of ionicity of a group that has been ionically dissociated by a change in pH as described above. ing. Further, this hydrophobic group has the ability to adsorb refractive index control fine particles in the optical element manufacturing method of the present invention described later, and imparts a good dispersion function to the polymer. Moreover, as a hydrophilic group, a hydroxyl group etc. can be mentioned besides an ionization group.
[0031]
The number of hydrophobic groups in the polymer having hydrophobic groups and hydrophilic groups is preferably in the range of 30% to 80% of the total number of hydrophilic groups and hydrophobic groups. If the number of hydrophobic groups is less than 30% of the total number of hydrophilic groups and hydrophobic groups, the formed film may be easily redissolved, and the water resistance and strength of the film may be insufficient. And more than 80% of the total number of hydrophobic groups, the solubility of the polymer in the aqueous liquid becomes insufficient, so that the electrodeposition liquid becomes cloudy, material precipitates are formed, and the viscosity of the electrodeposition liquid is low. Since it becomes easy to raise, it is desirable that it exists in the said range. The number of hydrophobic groups relative to the total number of hydrophilic groups and hydrophobic groups is more preferably in the range of 55% to 70%. In this range, the film deposition efficiency is particularly high, and the liquidity of the electrodeposition liquid is also stable. In addition, a film can be formed with an electrodeposition potential as low as a photovoltaic force.
[0032]
Examples of the polymer material include those obtained by copolymerizing a polymerizable monomer having a hydrophilic group and a polymerizable monomer having a hydrophobic group.
Examples of the polymerizable monomer containing a hydrophilic group include methacrylic acid, acrylic acid, hydroxyethyl methacrylate, acrylamide, maleic anhydride, fumaric acid, propiolic acid, itaconic acid, and derivatives thereof. It is not limited. Among these, methacrylic acid and acrylic acid are useful hydrophilic monomers because of high film deposition efficiency due to pH change.
In addition, a polymerizable monomer material containing a hydrophobic group, alkene, styrene, α-methylstyrene, α-ethylstyrene, methyl methacrylate, butyl methacrylate, acrylonitrile, vinyl acetate, ethyl acrylate, butyl acrylate, lauryl methacrylate, Etc. and derivatives thereof are used, but not limited thereto. In particular, since styrene and α-methylstyrene are highly hydrophobic, they are useful hydrophobic monomers that are easy to obtain hysteresis characteristics against re-dissolution.
As the polymer material used in the optical element production method of the present invention, a copolymer using acrylic acid or methacrylic acid as a hydrophilic group-containing monomer and styrene or α-methylstyrene as a hydrophobic group-containing monomer is preferably used.
[0033]
The polymer material used in the optical element manufacturing method of the present invention is a polymerizable monomer containing each of such a hydrophilic group and a hydrophobic group, preferably the ratio of the number of hydrophilic groups to hydrophobic groups in the polymer is The polymer material is copolymerized so that the ratio is as follows, and the type of each hydrophilic group and hydrophobic group is not limited to one.
[0034]
Examples of the functional material used in the present invention include refractive index control fine particles, pigment fine particles, dyes, and conductive fine particles.
Examples of refractive index control fine particles include high refractive index fine particles added to the core layer, and low refractive index fine particles added to the cladding layer. Examples of high refractive index fine particles include titanium oxide and zinc oxide, and low refractive index. Examples of the fine particles include fluorine compounds typified by magnesium fluoride.
The number average particle diameter of the fine particles is preferably from 0.2 to 150 nm, more preferably from 2 to 20 nm, from the viewpoints of dispersibility in the electrodeposition liquid and transparency of the electrodeposition film. When the number average particle diameter is less than 0.2 nm, the production cost increases, and stable quality may not be obtained. 150 nm (that is, 1.5 μm which is a wavelength band used for communication) If it exceeds 1/10), transparency will be reduced and internal irregular reflection will be caused, and internal loss will increase.
Also, as the functional material, a polymer material having a refractive index different from that of the main film-forming polymer material can be used as one of the film-forming polymer materials for adjusting the refractive index.
[0035]
  In the optical element manufacturing method of the present invention, the vicinity of the optical element manufacturing substrate (including the case of the vicinity of the conductive thin film or the optical semiconductor thin film, and the case of the thin film already formed, including the case of the vicinity of the thin film, the same applies hereinafter. To change the concentration of the functional material in the electrodeposition solutionLaw andIn order to obtain a thin film in which the functional material contained in the thin film has a density gradation in the thickness direction of the thin film, ElectricThere is a method in which an electrodeposition liquid having a functional material concentration different from that of the electrodeposition liquid flows out toward the optical element manufacturing substrate.Used. In this case, in order to achieve a uniform functional material concentration in the in-plane direction, the functional material concentration of the electrodeposition liquid should not be largely biased in the vicinity of the entire film formation region of the optical element manufacturing substrate. . For this purpose, a liquid flow having a shape corresponding to the film formation region can be flowed out, or a liquid flow can be flown out from the small holes arranged substantially evenly with respect to the film formation region. In order to manufacture the optical waveguide, a slit-like liquid flow having a shape corresponding to the core shape or a liquid flow from a plurality of small holes is directed toward the core formation region of the optical element manufacturing substrate. When a voltage is applied to the thin film formation area while flowing the liquid flow, the electrodeposition liquid having a different functional material concentration from the surrounding electrodeposition liquid comes into contact with the optical element manufacturing substrate and exists in the surrounding area. Thus, a thin film having a different functional material concentration is electrodeposited.
[0036]
  Therefore, when a film having a functional material concentration different from that of the film has already been formed, as in the case of forming a core layer on the clad layer, the electrodeposition solution in the electrodeposition tank is used. Even if it is not completely replaced (for example, from the electrodeposition liquid for the cladding layer to the electrodeposition liquid for the core layer), the electrodeposition liquids having different functional material concentrations are allowed to flow toward the film formation region, so that In addition, thin films having different functional material contents can be formed, which simplifies the process and contributes to cost reduction.
  In addition, by using a plurality of electrodeposition liquids with different functional material concentrations, the functional material concentration of the electrodeposition liquid that flows out toward the optical element fabrication substrate is changed over time, so that the function can be achieved in the formed thin film. The tone of the material can be given. In this case, if the concentration of the functional material of the electrodeposition liquid to be discharged is continuously changed, the content of the functional material in the thin film can be close to continuous gradation. For example, when forming the core layer, by appropriately selecting the functional material concentration in the plurality of electrodeposition liquids and their outflow order, an internal structure having a higher functional material concentration in the central portion of the core layer can be obtained. it can. In addition, if different electrodeposition liquids are continuously flowed out so that the concentration of the functional material becomes higher and then the outflow is stopped and then the voltage is continuously applied as it is, the concentration of the functional material to be electrodeposited decreases. (The concentration of the functional material in the first electrodeposition liquid for the cladding layer is lower than that for the core layer). This method can also form a core layer having a high concentration of the functional material in the central portion. it can.
  The flow rate of the liquid flow is 0.1 to 10 mm / second from the viewpoint of not damaging the already deposited portion and realizing concentration modulation corresponding to the deposition rate.The
[0037]
Further, the thin film itself formed by the method as described above has a uniform film thickness (the film is flat) regardless of the density gradation, so that the transfer is easy, and there are few bleeding and defects.
[0038]
In the optical element manufacturing method of the present invention, as another method of changing the concentration of the functional material in the electrodeposition liquid in the vicinity of the optical element manufacturing substrate, the functional material contained in the thin film is a film surface of the thin film. In order to obtain a thin film having a concentration gradation in the inward direction, for example, a liquid flow may be formed in the electrodeposition liquid so that the concentration of the functional material changes in the in-plane direction of the thin film formation region. . For example, in an electrodeposition solution, if an electrodeposition solution having a functional material concentration different from that of the electrodeposition solution is allowed to flow out only to a specific portion of the thin film formation region of the optical element manufacturing substrate, it hits the substrate. Since the posterior liquid flow flows around the substrate and diffuses into the electrodeposition liquid that originally exists, the concentration of the functional material in the electrodeposition liquid in the vicinity of the substrate is directed toward the direction in which the liquid flow flows along the substrate. Change. In addition, when the electrodeposition liquids having different functional material concentrations are allowed to flow out from the plurality of outlets toward the optical element fabrication substrate, a thin film in which the content of the functional material changes in the plane is obtained.
[0039]
Further, a three-dimensional density gradation is obtained by combining the method for producing the density gradation in the film thickness direction of the functional material and the method for producing the density gradation in the in-plane direction of the functional material film as described above. An optical element can be formed.
[0040]
Next, the optical element manufacturing method of the present invention will be described more specifically together with the apparatus used.
FIG. 3 shows an example of an apparatus for producing an optical element by a photoelectric deposition method.
The electrodeposition bath 20 stores the electrodeposition liquid 20 and at least the optical semiconductor of the optical element manufacturing substrate 10 (a laminate of the light-transmitting insulating substrate 12, the light-transmitting conductive film 14, and the optical semiconductor thin film 16). It arrange | positions at the electrodeposition liquid 20 so that the thin film 16 may contact. Above the electrodeposition liquid surface, a first imaging optical lens 73, a photomask 71, a second imaging optical lens 72, and a light source (not shown) for irradiating light are electrodeposition tank 80. The exposure means (projection type exposure apparatus) provided in this order from the side is provided, and the light 70 irradiated from the light source is imaged on the photomask 71 through the second imaging optical lens 72, and passes through the photomask 71. Then, the light is patterned and then imaged on the surface of the optical semiconductor thin film via the first imaging optical lens 73.
[0041]
In FIG. 3, 100 indicates an outflow plate for allowing an electrodeposition solution having a functional material concentration different from that of the electrodeposition solution 20 to flow out at a controlled flow rate, 102 indicates an outflow port provided in the outflow plate, and 106 indicates an electrode. A container 104 for storing the landing liquid, and a pressure supply means (pump) for supplying the electrodeposition liquid in 106 in a controlled amount, constitute a liquid flow forming mechanism. The flow rate of the electrodeposition liquid flowing out from the outlet is adjusted by controlling the pump. As described above, pulsation may occur as a characteristic of a pump that generates a liquid flow. However, there is no problem as long as the flow rate is within the previous period, and a known one can be appropriately selected and used. The concentration of the functional material in the electrodeposition liquid in the vicinity of the optical element manufacturing substrate is changed by flowing out an electrodeposition liquid having a functional material concentration different from that of the electrodeposition liquid 20 from the outlet 102 of the outflow plate 100. be able to. In addition, the distance from the outlet to the thin film formation position of the optical element fabrication substrate is appropriately about 0.2 to 10 mm in consideration of avoiding the risk of contact with the substrate and equalizing the flow rate.
In this embodiment, the outflow plate 100 also serves as the counter electrode 91 and is electrically connected to a voltage applying unit 90 that can apply a bias voltage such as a potentiostat, and the voltage applying unit 90 further includes a reference such as a saturated calomel electrode. It is connected to the electrode 92 and configured in a three-pole system. The voltage applying means 90 is connected to the conductive film 7 of the film forming substrate. Needless to say, the counter electrode can be provided at an appropriate position in the electrodeposition tank 80 without being used also as the outflow plate. When the hydrogen ion concentration can be changed sufficiently to cause film deposition only by the photovoltaic force, it is not necessary to apply a bias voltage from the voltage applying means, and therefore, a voltage is applied from the voltage applying means 90. There is no need to provide the voltage application means itself, but it is useful to provide the voltage application means in order to cope with various film forming substrates or electrodeposition conditions.
In addition, about the technique which forms the liquid flow of an electrodeposition liquid in an electrodeposition liquid, all the matters as described in Japanese Patent Application No. 2001-353725 which is a previous application by this applicant can be utilized.
[0042]
As an example of optical element production, a photoconductive device as shown in FIG. 3 is used to form a clad layer (lower part) on the entire surface of the substrate, and then the density gradation of the functional material (refractive index control fine particles) in the film thickness direction. A method of manufacturing an optical waveguide in which a core layer having a core and a clad layer (upper part) over the entire core layer is formed will be described.
First, the electrodeposition bath 80 is filled with the electrodeposition solution 20 for forming the lower clad layer, light is not irradiated, and a voltage exceeding the Schottky barrier of the optical semiconductor thin film of the optical element fabrication substrate is applied to the voltage applying means 90 and the counter electrode. A lower clad layer is formed on the entire surface of the substrate by applying the voltage between the substrate 91 (outflow plate 100).
Next, the core layer photomask (71) is set as shown in FIG. Further, the electrodeposition liquid for the lower core layer is put into the electrodeposition liquid storage container 106, and the electrodeposition liquid is allowed to flow out from the outlet 102 at a controlled rate. Thereafter, exposure is performed on the selected region so that light is imaged on the surface of the optical semiconductor thin film 8, and the bias voltage is applied to the film deposition by adding the photovoltaic force generated in the optical semiconductor thin film and the bias voltage. When the voltage is applied by the voltage application means 90 so as to exceed the necessary threshold voltage, the hydrogen ion concentration of the electrodeposition liquid in the vicinity of the exposed selected region changes greatly. Since the electrodeposition liquid contains an electrodeposition material whose solubility or dispersibility in aqueous liquid is reduced due to a change in hydrogen ion concentration, the solubility in the electrodeposition liquid in the selected region is reduced, and the lower cladding in the selected region is reduced. An electrodeposited film (lower core layer) containing fine particles for refractive index control is deposited on the surface of the layer. Thereafter, light irradiation, voltage application, and liquid outflow are stopped. Next, the electrodeposition liquid storage container 106 is replaced with an electrodeposition liquid for the upper core layer in which the concentration of the fine particles for refractive index control is different from that of the core layer electrodeposition liquid. A thin film (upper core layer) is formed by applying a bias voltage. A core layer having gradation in the content of fine particles for refractive index control in the film thickness direction is formed. In addition, when the liquid flow forming mechanism has a function capable of continuously flowing out the electrodeposition liquids having different functional material concentrations, after forming the lower core layer as described above, light irradiation or the like is performed. The upper core forming electrodeposition liquid may be continuously discharged without stopping and replacing the upper core forming electrodeposition liquid in the electrodeposition liquid storage container.
Next, the electrodeposition liquid in the electrolytic cell 80 is replaced with the electrodeposition liquid for the upper clad layer, and it is formed on the entire surface in the same manner as in the case of forming the lower clad layer without light irradiation.
[0043]
Next, another apparatus for producing an optical element by a photoelectric deposition method will be described. FIG. 4 is a conceptual diagram showing an optical element manufacturing apparatus similar to the apparatus shown in FIG. 3 except that a proximity exposure type exposure apparatus is used. Since the apparatus in FIG. 4 brings the photomask and the optical semiconductor thin film close to each other (the photomask is in close contact with the insulating substrate), an exposure apparatus having an imaging optical system and a mirror reflection optical system as in the apparatus of FIG. 3 is not used. A pattern with excellent resolution can be obtained. As the exposure device 75, a parallel light or contact type exposure device can be employed. As the irradiation light source, for example, a uniform irradiation light source of Hg—Xe can be used. In this case, it is effective to prevent the diffraction of light by setting the insulating substrate to 0.2 mm or less.
In order to produce the optical element as described above using this apparatus, the same operation as in the case of using the apparatus shown in FIG. 3 is performed. Further, when the lower and upper clad layers are produced, the entire surface of the optical element production substrate can be irradiated with light and photo-deposited.
[0044]
FIG. 5 is a conceptual diagram showing an optical element manufacturing apparatus similar to the apparatus shown in FIG. 3 except that a scanning laser writing apparatus is used as the exposure apparatus. In FIG. 5, reference numeral 78 denotes a scanning laser writing apparatus for laser beam irradiation such as He-Cd laser.
[0045]
Furthermore, FIG. 6 shows a conceptual diagram of an apparatus for producing an optical element by an electrodeposition method. Except not having an exposure apparatus, it has the same configuration as that shown in FIGS.
[0046]
In the optical element manufacturing method of the present invention, it is preferable to perform at least a step of heat-treating the optical element after forming all the optical elements. By performing such processing, the transmission loss of the optical element can be reduced.
Here, “all optical elements” means one or a plurality of all optical elements when one or a plurality of optical elements are formed (for example, one or more core layers and one or more cladding layers). Point to. “After forming” means “after depositing and forming the optical element” in the optical element manufacturing method using the optical element formed on the optical element manufacturing substrate by the (photo) electrodeposition method as it is. means. However, since the heat treatment is preferably performed after the water contained in the optical element is removed, it usually means after the drying process for removing the water. In addition, in the optical element manufacturing method in which the transfer is performed to the optical element substrate by the transfer method, it means “after the optical element is transferred to the optical element substrate”.
[0047]
The optical element deposited and formed by the (photo) electrodeposition method usually has a slight amount of moisture taken into the film, and therefore, a step of drying the optical element after the deposition and removing the moisture in the film is performed. However, it is presumed that a film defect (for example, a pinhole) occurs in the optical element due to the removal of moisture, which increases the transmission loss of the optical element. It is considered that this heat treatment in the present invention repairs the defects, further improves the surface roughness at the optical element surface and the core / cladding interface, and reduces transmission loss.
[0048]
The heat treatment may be any heat treatment that reduces the transmission loss of the optical element after the heat treatment as compared with that before the heat treatment, and the heating temperature and the heating time are not particularly limited. The heating temperature can take into consideration the glass transition temperature, flow start temperature, etc. of the polymer material used as the film-forming polymer material.
Moreover, in order to perform the said heat processing efficiently, it is preferable to heat more than the flow start temperature of a polymeric material. The above flow start temperature is described in “Polymer engineering course” 14, pages 364 to 369, edited by the Society of Polymer Science, Jijinshokan Co., Ltd., Showa 38). It means “temperature”. The flow starting temperature of the polymer material used in the present invention is generally within the range of 50 to 200 ° C, preferably 80 to 150 ° C, more preferably 110 to 130 ° C.
In addition, when pressure is applied to the optical element during the heat treatment, the heating time can be shortened or the heating temperature can be lowered.
[0049]
The electrodepositable polymer described above has a refractive index in the range of 1.45 to 1.6, is transparent in the deposited state, and has no absorption at wavelengths of 0.8 to 1.6 μm used for optical elements. It is suitable as an optical element material.
In addition, ultraviolet rays are not absorbed even when dissolved in water as an electrodeposition solution, so that the patterned semiconductor can be irradiated with pattern ultraviolet rays through the electrodeposition solution. Furthermore, since it can be electrodeposited at a low potential of 5 V or less, it is possible to form an electrodeposition pattern by photovoltaic power generated by an optical semiconductor.
[0050]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Example 1
In this example, an example of manufacturing an optical waveguide having a clad-core-clad structure is shown. (When the clad layer is formed, light is not irradiated and a voltage exceeding the Schottky barrier of the optical semiconductor is applied.)
(1) Preparation of electrodeposition solution for clad formation
100 g of pure water, 5 g of styrene-acrylic acid copolymer (molecular weight 13,000, copolymerization molar ratio of styrene and acrylic acid 65:35, acid value 150) (hereinafter referred to as “electrodepositing polymer material A”) And dimethylaminoethanol (water-soluble, liquid having a boiling point of 110 ° C. or higher and a vapor pressure of 100 mHg or lower) at a rate of 180 mmol / l, and further pH 7.8 using tetramethylammonium hydroxide and ammonium chloride. The conductivity was adjusted to 8 mS / cm, and this was used as an electrodeposition solution for forming a clad.
(2) Preparation of electrodeposition liquid 1 for core formation
5 g of the electrodepositable polymer material A and 5 g of titanium oxide having a diameter of 2 nm are dispersed and mixed in 100 g of pure water, dimethylaminoethanol is further added at a rate of 180 mmol / l, and tetramethylammonium hydroxide and ammonium chloride are used. Thus, the pH was adjusted to 7.8 and the conductivity was adjusted to 8 mS / cm.
(3) Preparation of electrodeposition liquid 2 for core formation
In the preparation of the core-forming electrodeposition solution 1, a core-forming electrodeposition solution 2 was prepared in the same manner as the preparation of the core-forming electrodeposition solution 1, except that the amount of titanium oxide was increased to 25 g.
(4) Fabrication of optical element fabrication substrate
A transparent conductive film of ITO was formed to a thickness of 100 nm on a 0.5 mm-thick alkali-free glass substrate (7059 glass) by sputtering, and 200 nm of TiO2 was further formed.₂Was formed by RF sputtering.
[0051]
(5) Fabrication of optical waveguide
A photodeposition apparatus having an electrodeposition liquid outflow mechanism as shown in FIG. 4 was used. The outflow plate is formed with a slit-shaped outlet corresponding to the core to be formed. In addition, using the outflow plate as a counter electrode (composed of platinum), TiO₂The electrode was used as a working electrode. A photomask (71) having an opening corresponding to the core to be formed was used, and a proximity exposure apparatus manufactured by Yamashita Denso was used as the exposure apparatus. And the distance from an outflow port to the core formation position of an optical element production board | substrate was 1 mm.
First, the electrodeposition tank was filled with the clad-forming electrodeposition solution, and a bias voltage applied to the working electrode was applied for 3.5 seconds without irradiating light from an exposure apparatus.₂A lower cladding layer having a thickness of 5 μm was formed on the entire surface.
[0052]
Next, without removing the optical element manufacturing substrate from the electrodeposition tank, the outflow of the core forming electrodeposition liquid 2 is 0.1 mm / second from the slit-shaped outlet of the electrodeposition liquid outflow plate toward the core formation position. Started with speed. Ten seconds after the start of outflow, with the bias voltage applied to the working electrode set at 1.8 V, the exposure apparatus used ultraviolet light having a wavelength of 365 nm (light intensity 50 mW / cm).²) For 15 seconds, a lower core layer having a thickness of 5 μm and a width of 10 μm was formed only in the region irradiated with light on the surface of the cladding layer.
Next, light irradiation and bias voltage application are stopped, the outflow electrodeposition liquid is replaced with the core forming electrodeposition liquid 1, and the outflow is started at a speed of 0.1 mm / sec from the slit-shaped outlet to the core forming position. did. Ten seconds after the start of outflow, with the bias voltage applied to the working electrode set at 1.8 V, the exposure apparatus used ultraviolet light having a wavelength of 365 nm (light intensity 50 mW / cm).²) For 15 seconds, an upper core layer having a thickness of 5 μm and a width of 10 μm was formed on the lower core layer.
[0053]
Next, the electrodeposition liquid in the electrodeposition tank was replaced with the electrodeposition liquid for clad formation described in (1) above, and a bias voltage applied to the working electrode was applied for 35 seconds without irradiating light from the exposure apparatus. However, an upper cladding layer having a thickness of 8 μm was formed on the entire surface.
[0054]
The optical element fabrication substrate is taken out from the electrodeposition bath, and dip cleaning is performed in pure water for 3 minutes to remove a slight amount of salt remaining in the film, and then drying with clean air to complete the optical waveguide substrate. It was.
When the obtained optical waveguide was cut into a length of 50 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 5 dB at a wavelength of 0.85 μm.
[0055]
Example 2
The optical waveguide produced in Example 1 was heat-treated at 140 ° C. for 3 minutes. Thereafter, when the transmission loss was measured in the same manner as in Example 1, it was found that the transmission loss was improved to about 1.5 dB. This is presumably due to the removal of pinholes that remained slightly in the optical waveguide film.
By having such a structure, even if the cladding layer in the film thickness direction is thin, the light confinement effect is increased, and the transmission loss is improved as compared with a simple step index type structure.
[0056]
Example 3
(1) Preparation of electrodeposition solution for clad formation
To 100 g of pure water, a copolymer of styrene and acrylic acid (copolymerization molar ratio of styrene and acrylic acid 20:80, acid value 160, molecular weight 12000) (hereinafter referred to as “electrodeposition polymer material B”). 5 g is dispersed and mixed, dimethylaminoethanol is further added at a rate of 180 mmol / l, and further adjusted to pH 7.8 and conductivity 8 mS / cm using tetramethylammonium hydroxide and ammonium chloride. A forming electrodeposition liquid was used.
(2) Preparation of electrodeposition liquid 1 for core formation
In 100 g of pure water, 5 g of the electrodepositable polymer material A in Example 1 and 5 g of the electrodepositable polymer material B are dispersed and mixed, dimethylaminoethanol is added at a rate of 180 mmol / l, and tetramethylammonium hydroxide is further added. Using ammonium chloride, the pH was adjusted to 7.8 and the conductivity was adjusted to 8 mS / cm.
(3) Preparation of electrodeposition liquid 2 for core formation
In the preparation of the core-forming electrodeposition liquid 1, the core-forming electrodeposition liquid 2 was prepared in the same manner as the preparation of the core-forming electrodeposition liquid 1, except that 5 g of the electrodepositable polymer material B was changed to 25 g. .
(4) Fabrication of optical element fabrication substrate
A transparent conductive film of ITO was formed to a thickness of 100 nm on a 0.5 mm-thick alkali-free glass substrate (7059 glass) by sputtering, and 200 nm of TiO2 was further formed.₂Was formed by RF sputtering.
[0057]
(5) Fabrication of optical waveguide
The photodeposition apparatus having the electrodeposition liquid outflow mechanism used in Example 1 was used.
First, the electrodeposition bath was filled with the electrodeposition solution for clad formation of (1), and a bias voltage applied to the working electrode was applied for 10 seconds without applying light from the exposure apparatus.₂A lower cladding layer having a thickness of 5 μm was formed on the entire surface.
[0058]
Next, without removing the optical element manufacturing substrate from the electrodeposition tank, the outflow of the core forming electrodeposition liquid 2 is 0.1 mm / second from the slit-shaped outlet of the electrodeposition liquid outflow plate toward the core formation position. Started with speed. Ten seconds after the start of outflow, with the bias voltage applied to the working electrode set at 1.8 V, the exposure apparatus used ultraviolet light having a wavelength of 365 nm (light intensity 50 mW / cm).²) For 15 seconds, a lower core layer having a thickness of 5 μm and a width of 10 μm was formed only in the region irradiated with light on the surface of the cladding layer.
Light irradiation and bias voltage application are stopped, the effluent electrodeposition solution is replaced with the core formation electrodeposition solution 1 described in (2) above, and the velocity is 0.1 mm / sec from the slit-shaped outlet to the core formation position. The spill started at. Ten seconds after the start of outflow, with the bias voltage applied to the working electrode set at 1.8 V, the exposure apparatus used ultraviolet light having a wavelength of 365 nm (light intensity 50 mW / cm).²) For 15 seconds, TiO₂An upper core layer having a thickness of 5 μm and a width of 10 μm was formed only in the region irradiated with light on the surface.
[0059]
Next, the electrodeposition solution for clad formation of (1) above was newly replaced in the electrodeposition bath, and the bias voltage applied to the working electrode was applied for 35 seconds without irradiating light from the exposure apparatus. An upper cladding layer of 8 μm was formed.
[0060]
The optical element fabrication substrate is taken out from the electrodeposition bath, and dip cleaning is performed in pure water for 3 minutes to remove a slight amount of salt remaining in the film, and then drying with clean air to complete the optical waveguide substrate. It was.
When the obtained optical waveguide was cut into a length of 50 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 4.5 dB at a wavelength of 0.85 μm.
[0061]
Example 4
The optical waveguide produced in Example 3 was heat-treated at 140 ° C. for 3 minutes. Thereafter, when the transmission loss was measured in the same manner as in Example 3, it was found that the transmission loss was improved to about 1.5 dB.
By having such a structure, even if the cladding layer in the film thickness direction is thin, the light confinement effect is increased, and the transmission loss is improved as compared with a simple step index type structure.
[0062]
Example 5
In this example, a circular thin film having a radius of 10 mm was formed on the optical element manufacturing substrate.
The same optical element production substrate as that in Example 1 was used. Further, an optical element manufacturing apparatus having a scanning laser exposure apparatus (He-Cd laser) as shown in FIG. 5 was used. The spot diameter of the He—Cd laser was set to 100 μm, and the optical system was set so that the optical element fabrication substrate could be scanned in a spiral manner at a speed of 0.05 mm per second. A circular outlet having a diameter of 1 mm was used as the outlet in the electrodeposition liquid outlet plate. The distance from the outlet to the thin film formation position on the optical element fabrication substrate was 1 mm.
The electrodeposition liquid for clad formation used in Example 1 was put in the electrodeposition tank. Furthermore, the electrodeposition liquid for core formation used in Example 1 is caused to flow out at a speed of 0.1 mm / second from the outflow port toward the center of the circle where the circular thin film is to be formed on the optical element manufacturing substrate. It was. Ten seconds after the start of outflow, a He—Cd laser was scanned in a spiral toward the center from a point 10 mm away from the center. A circular thin film having a radius of 10 mm and a thickness of 1 μm was formed (see FIG. 2).
This thin film has a refractive index of 1.7 at the center and 1.5 at the periphery, and the refractive index continuously changes from the periphery toward the center, and can be applied as a lens.
[0063]
Example 6
A separately prepared polyethylene film having a thickness of 0.2 mm is placed on the circular thin film produced in Example 5, and the linear velocity is measured between two rolls (roll surface temperature 170 ° C., linear pressure 300 g / cm). Heating and pressing treatment was performed at 20 mm / sec. A circular polymer thin film having a refractive index distribution was formed on the polyethylene film. The circular thin film produced in Example 5 had an extremely flat surface, so that transfer was easy and the shape did not collapse.
[0064]
【The invention's effect】
By using the optical element manufacturing method of the present invention, it is possible to easily make the density gradation of the functional material in the thin film, and it is not a step-like density change as in the prior art, but a gradual or continuous process. A density gradation can be obtained. Further, it is possible to create density gradations not only in the film thickness direction but also in the in-plane direction of the film, and further to combine these to obtain a three-dimensional density gradation. In addition, the thin film itself formed by precipitation has a uniform film thickness (film is flat) regardless of the density gradation, so that transfer is easy, and there are few bleeding and defects. Further, a developing sleeve that has a difference in the distribution of the inorganic conductive fine particles inside the resin as shown in Japanese Patent Laid-Open No. 8-160737 can also have more precise distribution characteristics.
[Brief description of the drawings]
FIG. 1 is a process diagram showing one embodiment of a method for producing an optical element of the present invention.
FIGS. 2A and 2B are a plan view and a cross-sectional view showing an example of an optical element obtained by the method of the present invention. FIGS.
FIG. 3 is a conceptual diagram showing an optical element manufacturing apparatus using a projection exposure apparatus.
FIG. 4 is a conceptual diagram showing an optical element manufacturing apparatus using a proximity exposure apparatus.
FIG. 5 is a conceptual diagram showing an optical element manufacturing apparatus using a scanning laser exposure apparatus.
FIG. 6 is a conceptual diagram showing an optical element manufacturing apparatus by electrodeposition.
[Explanation of symbols]
10 Optical element fabrication substrate
12 Insulating substrate
14 Conductive thin film
16 Optical semiconductor thin film
18, 22 Clad layer
20 Core layer
71 photomask
72, 73 Imaging optical lens
75 Hg-Xe uniform irradiation light source
78 Scanning laser writing device
100 Outflow plate (counter electrode)
102 outlet
104 Electrodeposition liquid pressure supply means
106 Electrodeposition liquid container

Claims (16)

An aqueous electrodeposition liquid containing a film-forming polymer material and a functional material, in which an optical element manufacturing substrate having a conductive thin film provided on an insulating substrate is reduced in solubility or dispersibility in an aqueous liquid by changing pH. In addition, a voltage is applied between the conductive thin film and the counter electrode in a state where at least the conductive thin film of the optical element manufacturing substrate is in contact with the electrodeposition liquid, and the above-mentioned conductive thin film is placed on the conductive thin film. An optical element manufacturing method including a step of depositing and forming a thin film containing a film-forming polymer material and a functional material, wherein the functional material concentration in the electrodeposition liquid is different from the functional material concentration of the electrodeposition liquid. By flowing the electrodeposition liquid having the electrodeposition liquid toward the optical element manufacturing substrate at a speed of 0.1 to 10 mm / second, and changing the concentration of the functional material in the electrodeposition liquid in the vicinity of the optical element manufacturing substrate, Included functionality An optical element manufacturing method comprising the step of fees to produce a thin film having a density gradation.   The method for producing an optical element according to claim 1, wherein the functional material contained in the thin film has a density gradation in the film thickness direction of the thin film.   2. The optical element manufacturing method according to claim 1, wherein the functional material contained in the thin film has a density gradation in an in-plane direction of the thin film. The method for producing an optical element according to claim 1 , wherein the functional material concentration of the electrodeposition liquid flowing out toward the optical element production substrate is changed over time.   The method for producing an optical element according to claim 1, wherein a step of transferring all the thin films formed on the optical element production substrate to another substrate is performed.   2. The method of manufacturing an optical element according to claim 1, further comprising a step of heat-treating the thin film after forming the thin film. An optical element manufacturing substrate in which a conductive thin film and an optical semiconductor thin film are laminated in this order on an insulating substrate is a film-forming polymer material and a functional material whose solubility or dispersibility in an aqueous liquid is lowered by changing pH. The selected region of the optical semiconductor thin film is irradiated with light in a state where at least the optical semiconductor thin film of the optical element manufacturing substrate is in contact with the electrodeposition liquid in an aqueous electrodeposition liquid containing An optical element manufacturing method comprising a step of applying a voltage between an optical semiconductor thin film and a counter electrode, and depositing and forming the film-forming polymer material and the functional material in a selected region of the semiconductor thin film , in, the functional material concentration of the electrodeposition solution was drained at a rate of 0.1 to 10 mm / sec toward the electrodeposition solution has a different functional material concentration in the optical element formation substrate, an optical element formation substrate near By varying the concentration of the functional material in the electrodeposition solution in the optical device manufacturing method comprising the functional material contained therein to produce a thin film having a density gradation. The optical element manufacturing method according to claim 7 , wherein the functional material contained in the thin film has a density gradation in the film thickness direction of the thin film. The optical element manufacturing method according to claim 7 , wherein the functional material contained in the thin film has a density gradation in an in-plane direction of the thin film. The method for producing an optical element according to claim 7 , wherein the functional material concentration of the electrodeposition liquid flowing out toward the optical element production substrate is changed over time. 8. The method according to claim 7 , further comprising a step of forming a thin film on the entire surface of the substrate by applying a voltage exceeding the Schottky barrier of the optical semiconductor thin film of the optical element fabrication substrate without irradiating light. Optical element manufacturing method. The optical element manufacturing method according to claim 7 , wherein a step of transferring all the thin films formed on the optical element manufacturing substrate to another substrate is performed. 8. The method of manufacturing an optical element according to claim 7 , further comprising a step of heat-treating the thin film after forming the thin film. An optical element manufacturing apparatus for manufacturing an optical element on an optical element manufacturing substrate in which a conductive thin film and an optical semiconductor thin film are laminated in this order on an insulating substrate, and the solubility or dispersion in an aqueous liquid by changing pH An electrodeposition tank for containing a water-based electrodeposition liquid containing a film-forming polymer material and a functional material with reduced properties, a counter electrode placed in the electrodeposition tank and electrically connected to the conductive thin film, An exposure means for irradiating light to the optical semiconductor thin film of the optical element manufacturing substrate, and a film-forming polymer material whose solubility or dispersibility in an aqueous liquid decreases due to pH change with respect to the optical element manufacturing substrate and a liquid flow forming mechanism for flow out at a rate of 0.1 to 10 mm / sec toward the electrodeposition liquid aqueous with different functional material concentration and the functional material concentration of the electrodeposition liquid to the optical element formation substrate With even without an optical element manufacturing apparatus for functional material contained therein to produce a thin film having a density gradation. Furthermore, the optical element manufacturing apparatus of Claim 14 provided with the voltage application means for applying a voltage between an electroconductive thin film and a counter electrode. An optical element manufacturing apparatus for manufacturing an optical element on an optical element manufacturing substrate in which a conductive thin film is provided on an insulating substrate, and forming a film whose solubility or dispersibility with respect to an aqueous liquid decreases due to pH change An electrodeposition tank for containing an aqueous electrodeposition liquid containing a polymer material and a functional material, a counter electrode placed in the electrodeposition tank and electrically connected to the conductive thin film, the conductive thin film and the counter electrode Of the film-forming polymer material and the electrodeposition liquid in which the solubility or dispersibility with respect to the aqueous liquid decreases due to the change in pH with respect to the voltage application means for applying a voltage between At least a liquid flow forming mechanism for flowing an aqueous electrodeposition liquid having a functional material concentration different from the functional material concentration toward the optical element fabrication substrate at a speed of 0.1 to 10 mm / second , included Optical element manufacturing apparatus for potential material to produce a thin film having a density gradation.

Images