Transfer film and method for manufacturing optical waveguide

Abstract

The present invention addresses the problem of providing: a transfer film that is used for manufacturing an optical waveguide member, and that enables formation of an EO layer having a reduced variation in thickness and exhibiting a high electro-optical constant; and a method for manufacturing an optical waveguide using the transfer film. A transfer film according to the present invention is used for manufacturing an optical waveguide member, and has a temporary support, an alignment layer, and an electro-optical layer containing an organic dye in the stated order.

Description

Transfer film and method for manufacturing optical waveguide

[0001] The present invention relates to a transfer film for producing an optical waveguide member and a method for producing an optical waveguide.

[0002] In recent years, organic electro-optic (EO) materials have been attracting attention as materials that can be used in optical control elements (optical elements) such as optical modulators, optical switches, and optical interconnects, from the perspective of realizing ultrafast optical communications.

[0003] For example, Patent Document 1 describes an electro-optical layer (hereinafter also abbreviated as "EO layer") containing a compound represented by the following formula (1) ([Claim 1] [Claim 5]).

[0004] Japanese Patent Application Laid-Open No. 2022-097407

[0005] The present inventors attempted to produce optical waveguide components (e.g., core layers, cladding layers, etc.) using the EO layer described in Patent Document 1, and found that when the EO layer is formed by coating as described in Patent Document 1, the thickness of the EO layer varies and the electro-optic constant of the EO layer decreases.

[0006] Therefore, an object of the present invention is to provide a transfer film used in the production of optical waveguide components, which suppresses thickness variation and is capable of forming an EO layer that exhibits a high electro-optic constant, and a method for producing an optical waveguide using the same.

[0007] As a result of intensive research aimed at achieving the above object, the present inventors have found that by using a transfer film having, in this order, a temporary support, an alignment layer, and an electro-optical layer (EO layer) containing an organic dye, it is possible to form an EO layer that exhibits a high electro-optical constant while suppressing thickness variations, and have completed the present invention. That is, the present inventors have found that the above object can be achieved by the following configuration.

[0008] [1] A transfer film for producing an optical waveguide member, having a temporary support, an alignment layer, and an electro-optical layer containing an organic dye, in this order. [2] The transfer film according to [1], further having a thermoplastic resin layer between the temporary support and the alignment layer. [3] The transfer film according to [2], wherein the thermoplastic resin layer has a melt viscosity of 200 to 3,000 Pa·s at 110°C. [4] The transfer film according to any one of [1] to [3], wherein the electro-optical layer has a melt viscosity of 350 to 180,000 Pa·s at 110°C. [5] The transfer film according to any one of [1] to [4], wherein the alignment layer is a rubbed alignment layer or a photoalignment layer. [6] The electro-optical layer has a second-order molecular susceptibility of 300×10 －３０ esu or higher. [7] The transfer film according to any one of [1] to [5], wherein the organic dye contained in the electro-optical layer has a degree of orientation of 0.25 to 0.95. [8] The transfer film according to any one of [1] to [7], wherein the electro-optical layer further contains a liquid crystal compound. [9] The transfer film according to [8], wherein the liquid crystal compound contained in the electro-optical layer has a degree of orientation of 0.50 to 0.95.

[10] The transfer film according to any one of [1] to [9], wherein the electro-optical layer further has a protective layer on the side opposite to the orientation layer.

[11] The transfer film according to

[10] , wherein the protective layer on the electro-optical layer side has a surface roughness Ra of 50 nm or less.

[12] The transfer film according to

[10] or

[11] , wherein the protective layer is a polypropylene film.

[13] The transfer film according to any one of [1] to

[12] , wherein the temporary support is a polymer film containing at least one selected from the group consisting of polypropylene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, and triacetyl cellulose.

[14] The transfer film according to

[13] , wherein the thickness of the temporary support is 5 to 200 μm.

[15] The transfer film according to [2] or [3], wherein the thickness of the thermoplastic resin layer is 2 to 20 μm.

[16] A method for producing an optical waveguide, comprising a step of laminating an electro-optical layer of the transfer film according to any one of [1] to

[15] to an object to be laminated, to form an optical waveguide.

[0009] According to the present invention, it is possible to provide a transfer film used for producing optical waveguide components, which has reduced thickness variation and is capable of forming an EO layer that exhibits a high electro-optic constant, and a method for producing an optical waveguide using the same.

[0010] Fig. 1 is a schematic cross-sectional view showing an example of the layer structure of the transfer film of the present invention, and Fig. 2 is a schematic cross-sectional view showing another example of the layer structure of the transfer film of the present invention.

[0011] The present invention will be described in detail below. The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the upper and lower limits. In this specification, the upper or lower limit of a numerical range described in stages may be replaced with the upper or lower limit of another numerical range described in stages. In addition, the upper or lower limit of a numerical range described in this specification may be replaced with a value shown in an example.

[0012] In addition, in this specification, for each component, a substance corresponding to the component may be used alone or in combination of two or more. Here, when two or more substances for each component are used in combination, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.

[0013] In addition, in this specification, "(meth)acrylate" is a notation representing "acrylate" or "methacrylate", "(meth)acrylic" is a notation representing "acrylic" or "methacrylic", and "(meth)acryloyl" is a notation representing "acryloyl" or "methacryloyl".

[0014] [Transfer film] The transfer film of the present invention is a transfer film for producing an optical waveguide member, which has a temporary support, an alignment layer, and an electro-optical layer (EO layer) containing an organic dye in this order. Furthermore, the transfer film of the present invention preferably further has a thermoplastic resin layer between the temporary support and the alignment layer, because this can prevent air bubbles from being mixed in when the EO layer is formed. Similarly, the transfer film of the present invention preferably further has a protective layer on the side of the electro-optical layer opposite the alignment layer, because this can prevent air bubbles from being mixed in when the EO layer is formed.

[0015] In the present invention, as described above, by using a transfer film having a temporary support, an alignment layer, and an electro-optical layer (EO layer) containing an organic dye in this order, thickness variation can be suppressed and an EO layer exhibiting a high electro-optical constant can be formed. The reason for this effect is not clear in detail, but the inventors speculate as follows. That is, in the present invention, by using a transfer film, it is possible to reduce or eliminate contact of a solvent with the underlying circuitry, etc., and form an electro-optical layer containing an organic dye, thereby suppressing thickness variation of the EO layer and, as a result, increasing the electro-optical constant.

[0016] Next, the layer structure of the transfer film of the present invention will be described with reference to the drawings. The transfer film 10 shown in Fig. 1 has a temporary support 11, an alignment layer 12, and an electro-optical layer 13 containing an organic dye, in this order. The transfer film 20 shown in Fig. 2 further has a thermoplastic resin layer 14 between the temporary support 11 and the alignment layer 12, and further has a protective layer 15 on the side of the electro-optical layer 13 opposite the alignment layer 12. Each component of the transfer film of the present invention will be described in detail below.

[0017] [Temporary Support] The temporary support of the transfer film of the present invention is a member that supports the alignment layer or the electro-optical layer described below, and is a member that is removed after the optical waveguide member is produced.

[0018] The temporary support may have either a single-layer structure or a multilayer structure. As the temporary support, a film is preferred, and a polymer film is more preferred. Furthermore, as the temporary support, a polymer film that is flexible and does not significantly deform, shrink, or stretch under pressure or under pressure and heat is also preferred, and a polymer film that is free from deformation such as wrinkles and scratches is also preferred. Examples of such polymer films include polymer films containing at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and triacetyl cellulose (TAC), and a polyethylene terephthalate film is preferred.

[0019] The thickness of the temporary support is not particularly limited, but from the viewpoint of ease of handling and versatility, it is preferably 5 to 200 μm, more preferably 5 to 150 μm, and even more preferably 5 to 100 μm. Here, the thickness of the temporary support is calculated as the average value when 100 points are measured at 1 cm intervals over an area of ​​10 cm × 10 cm using a pencil-type high-precision digital length measuring instrument PHA-13W manufactured by Tosei Engineering Co., Ltd., with an E-ST-100DB stand attached, and a MINICOM-M (Model E-M) as a display device.

[0020] [Alignment Layer] The alignment layer of the transfer film of the present invention may be any layer that can achieve the desired alignment state for the organic dye contained in the electro-optical layer described below. Methods for forming the alignment layer include, for example, rubbing an organic compound (preferably a polymer) onto the film surface, oblique vapor deposition of an inorganic compound, formation of a layer with microgrooves, and accumulation of an organic compound (e.g., ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearate, etc.) using the Langmuir-Blodgett method (LB film). Furthermore, alignment layers that exhibit alignment function upon application of an electric field, a magnetic field, or light irradiation are also known. Alternatively, the alignment layer may be formed by a single coating of the electro-optical layer described below. For example, a composition containing an organic dye and an alignment agent may be applied to a temporary support, and the alignment agent may spontaneously become ubiquitous on the temporary support side before or during evaporation of the solvent from the coating solution, thereby forming an alignment layer. The alignment layer formed in this manner is defined as a portion where the alignment agent component constituting the film per 1 g is 50% by mass or more after the solvent has evaporated.

[0021] The thickness of the alignment layer is not particularly limited, but is preferably 0.01 to 2.0 μm, and more preferably 0.01 to 1.0 μm. The thickness of the alignment layer is calculated as the average value of measurements taken at any five points using a surface roughness meter (for example, P-10 (manufactured by TENCOR Corporation)).

[0022] In the present invention, an alignment layer formed by rubbing treatment (rubbed alignment layer) is preferred from the viewpoint of ease of control of the pretilt angle of the alignment layer, and a photo-alignment layer formed by light irradiation is preferred from the viewpoint of uniformity of alignment.

[0023] <Rubbing Treatment Alignment Layer> Polymer materials used for the alignment layer formed by rubbing treatment are described in many literatures, and many commercially available products are available. In the present invention, polyvinyl alcohol or polyimide, and derivatives thereof are preferably used. For details of the alignment layer, please refer to the description on page 43, line 24 to page 49, line 8 of WO 2001 / 88574 A1.

[0024] <Photo-alignment layer> Photo-alignment compounds used in the alignment layer formed by light irradiation are described in many documents, etc. In the present invention, for example, azo compounds described in JP-A Nos. 2006-285197, 2007-76839, 2007-138138, 2007-94071, 2007-121721, 2007-140465, 2007-156439, 2007-133184, 2009-109831, Japanese Patent Nos. 3883848 and 4151746, and azo compounds described in JP-A No. 2002-229039 are used. Preferred examples include the aromatic ester compounds described in JP-A Nos. 2002-265541 and 2002-317013, maleimide and / or alkenyl-substituted nadimide compounds having a photoalignment unit, photocrosslinkable silane derivatives described in Japanese Patent Nos. 4205195 and 4205198, and photocrosslinkable polyimides, polyamides, or esters described in Japanese Patent Publication Nos. 2003-520878, 2004-529220, or Japanese Patent No. 4162850. Azo compounds, photocrosslinkable polyimides, polyamides, or esters are more preferred.

[0025] Among these, it is preferable to use a photosensitive compound having a photo-alignment group that undergoes at least one of dimerization and isomerization under the action of light as the photo-alignment compound.In addition, as the photo-alignment group, for example, a group having a cinnamic acid (cinnamoyl) structure (skeleton), a group having a coumarin structure (skeleton), a group having a chalcone structure (skeleton), a group having a benzophenone structure (skeleton), and a group having an anthracene structure (skeleton) can be mentioned.Among these groups, a group having a cinnamoyl structure and a group having a coumarin structure are preferred, and a group having a cinnamoyl structure is more preferred.

[0026] The photosensitive compound having the photoalignable group may further have a crosslinkable group. The crosslinkable group is preferably a thermally crosslinkable group that undergoes a curing reaction under the action of heat, or a photocrosslinkable group that undergoes a curing reaction under the action of light, and may be a crosslinkable group having both a thermally crosslinkable group and a photocrosslinkable group. Examples of the crosslinkable group include an epoxy group, an oxetanyl group, -NH-CH ２ Examples of the group include at least one selected from the group consisting of a group represented by -O-R (R represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms), a group having an ethylenically unsaturated double bond, and a blocked isocyanate group. Among these, an epoxy group, an oxetanyl group, and a group having an ethylenically unsaturated double bond are preferred. A three-membered cyclic ether group is also called an epoxy group, and a four-membered cyclic ether group is also called an oxetanyl group. Specific examples of the group having an ethylenically unsaturated double bond include a vinyl group, an allyl group, a styryl group, an acryloyl group, and a methacryloyl group, with an acryloyl group or a methacryloyl group being preferred.

[0027] A photo-alignment layer formed from the above materials is irradiated with linearly polarized or non-polarized light to produce a photo-alignment layer. In this specification, "linearly polarized light irradiation" and "non-polarized light irradiation" refer to operations for causing a photoreaction in the photo-alignment material. The wavelength of the light used varies depending on the photo-alignment material used, and is not particularly limited as long as it is the wavelength necessary for the photoreaction. The peak wavelength of the light used for photoirradiation is preferably 200 nm to 700 nm, and ultraviolet light with a peak wavelength of 400 nm or less is more preferred.

[0028] Examples of light sources used for light irradiation include commonly used light sources, such as lamps such as tungsten lamps, halogen lamps, xenon lamps, xenon flash lamps, mercury lamps, mercury xenon lamps, and carbon arc lamps, various lasers [e.g., semiconductor lasers, helium-neon lasers, argon ion lasers, helium-cadmium lasers, and YAG (yttrium aluminum garnet) lasers], light-emitting diodes, and cathode ray tubes.

[0029] As a means for obtaining linearly polarized light, a method using a polarizing plate (e.g., an iodine polarizing plate, a dichroic dye polarizing plate, and a wire grid polarizing plate), a method using a prism element (e.g., a Glan-Thompson prism) or a reflective polarizer utilizing the Brewster angle, or a method using light emitted from a polarized laser light source can be employed. Alternatively, a filter or a wavelength conversion element may be used to selectively irradiate only light of a required wavelength.

[0030] When the light to be irradiated is linearly polarized light, a method is adopted in which the light is irradiated from the top or back surface of the alignment layer perpendicularly or obliquely to the surface of the alignment layer. The incident angle of the light varies depending on the photo-alignment material, but is preferably 0 to 90° (perpendicular), and more preferably 40 to 90°. When the light is non-polarized light, the alignment layer is irradiated with non-polarized light obliquely. The incident angle is preferably 10 to 80°, more preferably 20 to 60°, and even more preferably 30 to 50°. The irradiation time is preferably 1 to 60 minutes, and more preferably 1 to 10 minutes.

[0031] When patterning is required, a method of irradiating light using a photomask the number of times required to form a pattern, or a method of writing a pattern by laser light scanning can be used.

[0032] [Electro-optical Layer (EO Layer)] The electro-optical layer (EO layer) of the transfer film of the present invention is an organic layer containing an organic dye.

[0033] Furthermore, the electro-optical layer of the transfer film of the present invention may or may not have been subjected to poling treatment. Therefore, if the electro-optical layer of the transfer film of the present invention has not been subjected to poling treatment, poling can be performed after the electro-optical layer is transferred, i.e., at the stage of producing an optical waveguide member. Here, the poling treatment is not particularly limited, and known poling treatments such as optical poling and electric field poling can be used. Among these, the electric field poling method is particularly preferred in terms of the simplicity of the apparatus and the high degree of orientation obtained. The electric field poling method can be broadly divided into a contact poling method in which a nonlinear optical material is sandwiched between a pair of electrodes and an electric field is applied, and a corona poling method in which corona discharge is applied to the surface of a nonlinear optical material on a substrate electrode and a charging electric field is applied.

[0034] <Organic Dye> The organic dye contained in the electro-optical layer is not particularly limited, and any conventionally known organic EO material can be used. The concentration of the organic dye is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, relative to the mass of the EO layer, because this allows the formation of an EO layer exhibiting a higher electro-optical constant and also allows the suppression of orientation relaxation over time.

[0035] In the present invention, from the viewpoint of reducing power consumption (reducing driving voltage) and miniaturizing the EO element, the electro-optic layer has a second-order molecular susceptibility of 300×10 －３０ It is preferable that the organic dye contained in the film is 500×10 －３０ More than 10000 x 10 －３０ It is more preferable that the organic dye contains an organic dye of esu or less. Here, the second-order molecular susceptibility of the organic dye is a value calculated by the density functional method using Gaussian 16 under the following conditions: Functional: M06x02 Basis function: 6-31+g(d,p) Solvent effect: chloroform Other conditions: default values ​​of Gaussian 16

[0036] In the present invention, the degree of orientation of the organic dye contained in the electro-optical layer is preferably 0.25 or more, more preferably 0.40 or more, and even more preferably 0.50 or more, because this reduces power consumption. While there is also a method of increasing the degree of orientation to 0.95 or more by crystallizing the dye, the crystallization of the dye causes light scattering from the fine particles, reducing the light transmission rate within the fiber. Therefore, the degree of orientation of the organic dye contained in the electro-optical layer is preferably 0.99 or less, more preferably 0.98 or less, and even more preferably 0.95 or less. When the dye does not crystallize, there is no upper limit to the degree of orientation, but it is usually 0.99 or less. Here, the degree of orientation of the organic dye refers to a value calculated using the following procedure. With a linear polarizer inserted on the light source side of an optical microscope (for example, an "ECLIPSE E600 POL" product manufactured by Nikon Corporation), a laminate having an electro-optical layer is set on a sample stage, and the absorbance of the electro-optical layer in the wavelength range of 380 nm to 780 nm is measured at 1 nm intervals using a multichannel spectrometer (manufactured by Ocean Optics, product name "QE65000"), and the degree of orientation in the range of 400 nm to 700 nm is calculated using the following formula: Orientation degree: S = ((Az0 / Ay0) - 1) / ((Az0 / Ay0) + 2) In the above formula, "Az0" represents the absorbance for polarized light in the absorption axis direction of the electro-optical layer, and "Ay0" represents the absorbance for polarized light in the transmission axis direction of the electro-optical layer.

[0037] In the present invention, from the viewpoint of conformability to unevenness and prevention of entrapment of air bubbles, the melt viscosity of the electro-optical layer at 110°C is preferably 350 to 180,000 Pa·s, and more preferably 3,000 to 30,000 Pa·s. Here, the melt viscosity of the electro-optical layer at 110°C refers to a value measured at a temperature of 110°C and a frequency of 1 Hz using a viscoelasticity measuring device (for example, a DynAlyser DAS-100 manufactured by International Co. Ltd.).

[0038] <Liquid Crystal Compound> In the present invention, it is preferable that the electro-optical layer further contains a liquid crystal compound because it can increase the degree of orientation of the organic dye described above. As the liquid crystal compound, either a polymer liquid crystal compound or a low molecular weight liquid crystal compound can be used, with a polymer liquid crystal compound being preferred because it can increase the degree of orientation. Furthermore, as the liquid crystal compound, a polymer liquid crystal compound and a low molecular weight liquid crystal compound may be used in combination. Here, "polymer liquid crystal compound" refers to a liquid crystal compound having a repeating unit in its chemical structure. Furthermore, "low molecular weight liquid crystal compound" refers to a liquid crystal compound having no repeating unit in its chemical structure. Examples of polymer liquid crystal compounds include the thermotropic liquid crystal polymers described in JP 2011-237513 A and the polymer liquid crystal compounds described in paragraphs

[0012] to

[0042] of WO 2018 / 199096 A. Examples of low molecular weight liquid crystal compounds include those described in paragraphs

[0072] to

[0088] of JP 2013-228706 A, and among them, liquid crystal compounds exhibiting smectic properties are preferred. Examples of such liquid crystal compounds include those described in paragraphs

[0019] to

[0140] of WO 2022 / 014340 A, and these descriptions are incorporated herein by reference.

[0039] In particular, preferred examples of the polymer liquid crystal compound include liquid crystal compounds having a repeating unit represented by the following formula (1), which is described in paragraph

[0014] of WO 2018 / 199096:

[0040] In the above formula (1), R １ represents a hydrogen atom or a methyl group, L １ and L ２ each independently represents a single bond or a divalent linking group; M １ represents a mesogen group represented by formula (1-1) described below, T １ represents a terminal group.

[0041] Furthermore, suitable examples of the low molecular weight liquid crystal compound include the compound represented by the following formula (2) described in paragraph

[0074] of JP-A No. 2013-228706:１ -V １ -W １ -X １ -Y １ -X ２ -Y ２ -X ３ -W ２ -V ２ -U ２ (2) [In formula (2), X １ , X ２ and X ３ each independently represents an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group, provided that X １ , X ２ and X ３ At least one of the groups is a 1,4-phenylene group which may have a substituent. The -CH2- constituting the cyclohexane-1,4-diyl group which may have a substituent may be replaced by -O-, -S- or -NR-. R is an alkyl group having 1 to 6 carbon atoms or a phenyl group. Y １ and Y ２ are each independently —CH ２ CH ２ -, -CH ２ O-, -COO-, -OCOO-, single bond, -N=N-, -CR ａ =CR ｂ -, -C≡C- or -CR ａ =N-. ａ and R ｂ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. １ represents a hydrogen atom or a polymerizable group. ２ represents a polymerizable group. １ and W ２ each independently represents a single bond, —O—, —S—, —COO— or —OCOO—. １ and V ２ each independently represents an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, and —CH ２ - may be replaced by -O-, -S- or -NH-.]

[0042] When the electro-optical layer contains a liquid crystal compound, the content of the liquid crystal compound is preferably 40 to 95 parts by mass, and more preferably 50 to 90 parts by mass, relative to 100 parts by mass of the content of the organic dye described above. When the electro-optical layer contains a liquid crystal compound, the content of the liquid crystal compound is preferably 40 to 95 parts by mass, and more preferably 50 to 90 parts by mass, relative to 100 parts by mass of the total content of the organic dye and the liquid crystal compound.

[0043] In the present invention, because the degree of orientation of the organic dye is high, the degree of orientation of any liquid crystal compound contained in the electro-optical layer is preferably 0.50 to 0.95, and more preferably 0.7 to 0.95. Here, the degree of orientation of the liquid crystal compound refers to the degree of vertical orientation calculated by the following procedure. First, a Fourier transform infrared spectrophotometer (e.g., VERTEX70 manufactured by Bruker) is used to perform polarized ATR (Attenuated Total Reflectance)-IR (Infrared Spectroscopy) measurement (ATR crystal: Ge, incident angle: 45 degrees) on the incident polarization (P / S) of the measurement target (electro-optical layer containing an organic dye and a liquid crystal compound) to determine the three-dimensional absorption coefficient. Next, the degree of orientation P in the z-axis direction is calculated from the determined three-dimensional absorption coefficient using the following formula: ２ｚ Since the liquid crystal compound is isotropic, it is assumed that the refractive index is 1.5 and that the liquid crystal compound is uniaxially aligned in the z-axis direction. ２Ｚ = (k ｚ / k ｘ −1) / (k ｚ / k ｘ +2) k ｘ = k ｙ = 1.5

[0044] The thickness of the electro-optical layer is not particularly limited, but is preferably 0.3 to 5.0 μm, and more preferably 1.0 to 3.0 μm, in consideration of connection with an optical fiber. Here, the thickness of the electro-optical layer is calculated as the average value of measurements taken at any five points using a surface roughness meter (for example, P-10 (manufactured by TENCOR Corporation)).

[0045] <Method for forming electro-optical layer> The method for forming the electro-optical layer is not particularly limited, but may include a method including, in this order, a step of applying a composition containing the above-mentioned organic dye and liquid crystal compound (hereinafter also referred to as "EO composition") onto the above-mentioned alignment layer to form a coating film (hereinafter also referred to as "coating film forming step"), and a step of orienting the organic dye and liquid crystal compound contained in the coating film (hereinafter also referred to as "orientation step").

[0046] (Vertical Alignment Agent) The EO composition preferably contains a vertical alignment agent. Here, the vertical alignment agent refers to an additive that has the function of aligning the above-mentioned liquid crystal compound in a direction perpendicular to the main plane of the electro-optical layer. Note that "vertical alignment" does not require alignment at strictly 90°, but means alignment at an angle of 70 to 110°.

[0047] Examples of the vertical alignment agent include an ionic vertical alignment agent and a vertical alignment agent having a boronic acid group, and it is preferable to use an ionic vertical alignment agent and a vertical alignment agent having a boronic acid group in combination. Here, examples of the vertical alignment agent include those described in paragraphs

[0180] to

[0202] of JP-A-2023-4859, the disclosures of which are incorporated herein by reference.

[0048] (Solvent) From the viewpoint of workability and the like, the EO composition preferably contains a solvent. Examples of the solvent include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, acetylacetone, etc.), ethers (e.g., dioxane, tetrahydrofuran, tetrahydropyran, dioxolane, tetrahydrofurfuryl alcohol, cyclopentyl methyl ether, dibutyl ether, etc.), aliphatic hydrocarbons (e.g., hexane, etc.), alicyclic hydrocarbons (e.g., cyclohexane, etc.), aromatic hydrocarbons (e.g., benzene, toluene, xylene, tetralin, trimethylbenzene, etc.), halogenated carbons (e.g., dichloromethane, trichloromethane (chloroform), dichloroethane, dichlorobenzene, 1,1,2,2-tetrachloroethane, chlorotoluene, etc.), esters (e.g., methyl acetate, ethyl acetate, butyl acetate, diethyl carbonate, ethyl acetoacetate, n-pentyl acetate, ethyl benzoate, benzyl benzoate, butyl carbitol acetate, diethylene glycol monoethyl ether acetate, Examples of suitable solvents include organic solvents such as ethanol, isopropanol, butanol, cyclohexanol, furfuryl alcohol, 2-ethylhexanol, octanol, benzyl alcohol, ethanolamine, ethylene glycol, propylene glycol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, phenols (e.g., phenol, cresol, etc.), cellosolves (e.g., methyl cellosolve, ethyl cellosolve, 1,2-dimethoxyethane, etc.), cellosolve acetates, sulfoxides (e.g., dimethyl sulfoxide, etc.), amides (e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc.), and heterocyclic compounds (e.g., pyridine, 2,6-lutidine, etc.), as well as water. These solvents may be used alone or in combination of two or more.

[0049] (Polymerization initiator) The EO composition may contain a polymerization initiator. There are no particular limitations on the polymerization initiator, but it is preferably a photosensitive compound, i.e., a photopolymerization initiator. As the photopolymerization initiator, various compounds can be used without particular limitations. Examples of photopolymerization initiators include α-carbonyl compounds (U.S. Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (U.S. Pat. No. 2,448,828), α-hydrocarbon-substituted aromatic acyloin compounds (U.S. Pat. No. 2,722,512), polynuclear quinone compounds (U.S. Pat. Nos. 3,046,127 and 2,951,758), and combinations of triarylimidazole dimers and p-aminophenyl ketones (U.S. Pat. No. 3,549,367). ), acridine and phenazine compounds (JP 60-105667 A and U.S. Pat. No. 4,239,850 A), oxadiazole compounds (U.S. Pat. No. 4,212,970 A), o-acyloxime compounds (JP 2016-27384 A

[0065] ), and acylphosphine oxide compounds (JP 63-40799 A, JP 5-29234 A, JP 10-95788 A, and JP 10-29997 A). Commercially available photopolymerization initiators can also be used, including Irgacure-184, Irgacure-907, Irgacure-369, Irgacure-651, Irgacure-819, Irgacure-OXE-01, and Irgacure-OXE-02 manufactured by BASF.

[0050] (Interfacial improver) The EO composition may contain an interfacial improver. There are no particular limitations on the interfacial improver, and polymeric interfacial improvers and low molecular weight interfacial improvers can be used, including the compounds described in paragraphs

[0253] to

[0293] of JP-A No. 2011-237513. Furthermore, fluorine (meth)acrylate polymers described in paragraphs

[0018] to

[0043] of JP-A No. 2007-272185 can also be used as interfacial improvers. Examples of the interface improver include compounds described in paragraphs

[0079] to

[0102] of JP-A-2007-069471, polymerizable liquid crystal compounds represented by formula (4) described in JP-A-2013-047204 (particularly compounds described in paragraphs

[0020] to

[0032] ), polymerizable liquid crystal compounds represented by formula (4) described in JP-A-2012-211306 (particularly compounds described in paragraphs

[0022] to

[0029] ), and liquid crystal alignment promoters represented by formula (4) described in JP-A-2002-129162 (particularly compounds described in paragraphs

[0032] to

[0032] ). The compounds described in paragraphs

[0076] to

[0078] and

[0082] to

[0084] of the present invention, the compounds represented by formulas (4), (II) and (III) described in JP-A-2005-099248 (particularly the compounds described in paragraphs

[0092] to

[0096] ), the compounds described in paragraphs

[0013] to

[0059] of Japanese Patent No. 4,385,997, the compounds described in paragraphs

[0018] to

[0044] of Japanese Patent No. 5,034,200, and the compounds described in paragraphs

[0019] to

[0038] of Japanese Patent No. 4,895,088 can also be used. The interfacial modifiers may be used alone or in combination of two or more.

[0051] (Coating Film Forming Step) The coating film forming step is a step of forming a coating film by applying an EO composition. The EO composition can be easily applied by using an EO composition containing the above-mentioned solvent or by using an EO composition that has been converted into a liquid such as a molten liquid by heating or the like. Specific examples of the method for applying the EO composition include known methods such as roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spraying, and inkjet printing.

[0052] (Orientation Step) The orientation step is a step of orienting the organic dye and liquid crystal compound contained in the coating film. This results in an electro-optical layer. The orientation step may include a drying treatment. Components such as the solvent can be removed from the coating film by the drying treatment. The drying treatment may be performed by leaving the coating film at room temperature for a predetermined time (e.g., natural drying), or by heating and / or blowing air. Here, the organic dye and liquid crystal compound contained in the EO composition may be aligned by the above-mentioned coating film formation step or drying treatment. For example, in an embodiment in which the EO composition is prepared as a coating liquid containing a solvent, the coating film is dried to remove the solvent from the coating film, thereby obtaining an EO layer.

[0053] The orientation step preferably includes a heat treatment. This allows the organic dye and liquid crystal compound contained in the coating film to be oriented, and the coating film after the heat treatment can be suitably used as an EO layer. From the viewpoint of manufacturability, the heat treatment is preferably performed at a temperature of 10 to 250°C, more preferably 25 to 190°C. The heating time is preferably 1 to 300 seconds, more preferably 1 to 60 seconds.

[0054] The orientation step may include a cooling treatment carried out after the heating treatment. The cooling treatment is a treatment in which the coated film after heating is cooled to about room temperature (20 to 25°C). This allows the orientation of the organic dye and liquid crystal compound contained in the coated film to be fixed. The cooling method is not particularly limited and can be carried out by a known method.

[0055] (Other Steps) The method for forming an electro-optical layer may include a step of curing the electro-optical layer (hereinafter also referred to as a "curing step") after the alignment step. For example, when a component contained in the electro-optical layer (or the EO composition) has a crosslinkable group (polymerizable group), the curing step is performed by heating and / or light irradiation (exposure). Among these, the curing step is preferably performed by light irradiation. Furthermore, the method for forming an electro-optical layer may include a step of performing the above-mentioned poling treatment after the alignment step (or the curing step).

[0056] [Thermoplastic Resin Layer] As described above, the transfer film of the present invention preferably further comprises a thermoplastic resin layer between the temporary support and the alignment layer, for the reason that the inclusion of air bubbles during the formation of the EO layer can be suppressed. Here, the thermoplastic resin layer serves as a cushioning material so as to absorb unevenness (including unevenness due to an already formed image, etc.) on the surface of the base to which the electro-optical layer is transferred, and preferably has the property of being able to deform in accordance with the unevenness.

[0057] In the present invention, the thermoplastic resin layer is preferably alkali-soluble. The thermoplastic resin layer preferably contains, as a component, an organic polymer substance described in JP-A-5-72724, and particularly preferably contains at least one organic polymer substance having a softening point of about 80° C. or less as determined by the Vicat method (specifically, a polymer softening point measurement method according to ASTM D1235).

[0058] Specific examples of organic polymer substances include polyolefins such as polyethylene and polypropylene, ethylene copolymers of ethylene and vinyl acetate or saponified products thereof, copolymers of ethylene and acrylic acid esters or saponified products thereof, polyvinyl chloride and vinyl chloride copolymers of vinyl chloride and vinyl acetate or saponified products thereof, polyvinylidene chloride, vinylidene chloride copolymers, polystyrene, styrene copolymers of styrene and (meth)acrylic acid esters or saponified products thereof, polyvinyl toluene, vinyl toluene copolymers of vinyl toluene and (meth)acrylic acid esters or saponified products thereof, poly(meth)acrylic acid esters, (meth)acrylic acid ester copolymers of butyl (meth)acrylate and vinyl acetate, etc., vinyl acetate copolymer nylons, copolymer nylons, N-alkoxymethylated nylons, and polyamide resins such as N-dimethylaminated nylons.

[0059] The thickness of the thermoplastic resin layer is not particularly limited, but is preferably 2 to 20 μm, more preferably 2 to 14 μm, because it provides sufficient conformability to the irregularities of the base surface and reduces the load associated with drying during formation of the thermoplastic resin layer. Here, the thickness of the thermoplastic resin layer is calculated as the average value of measurements taken at any five points using a surface roughness meter (for example, P-10 (manufactured by TENCOR Corporation)).

[0060] The thermoplastic resin layer can be formed by coating a preparation liquid containing an organic polymer substance, and the preparation liquid used for coating can be prepared using a solvent. The solvent is not particularly limited as long as it can dissolve the organic polymer substance, and examples thereof include methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether acetate, n-propanol, and 2-propanol.

[0061] In the present invention, the melt viscosity η of the thermoplastic resin layer at 110 ° C. is preferably 200 to 3000 Pa · S, more preferably 300 to 2500 Pa · s, and even more preferably 500 to 2000 Pa · s, because the workability during transfer is good and the ability to follow the unevenness of the base surface is sufficient. Here, the melt viscosity of the thermoplastic resin layer at 110 ° C. is a value measured at a temperature of 110 ° C. and a frequency of 1 Hz using a viscoelasticity measuring device (for example, a DynAlyser DAS-100 manufactured by International Co. Ltd.).

[0062] One way to adjust the melt viscosity η of the thermoplastic resin layer within the above range is to adjust the content of low-molecular-weight polymers and plasticizers in the binder (e.g., the organic polymeric substances described above) contained in the thermoplastic resin layer. The ratio of high-molecular-weight polymers to low-molecular-weight polymers in the polymers constituting the thermoplastic resin layer is preferably 10 / 90 or more and less than 45 / 55, more preferably 12 / 88 or more and less than 40 / 60, and most preferably 15 / 85 or more and less than 38 / 62. Here, a low-molecular-weight polymer refers to a polymer with a weight-average molecular weight of 3,000 or more and less than 10,000.

[0063] The amount of the plasticizer added is preferably 28 to 43% by mass, more preferably 30 to 40% by mass, and even more preferably 32 to 38% by mass, based on the mass of the solid content of the binder and plasticizer contained in the thermoplastic resin layer.

[0064] [Protective Layer] As described above, the transfer film of the present invention preferably has a highly smooth protective layer on the side opposite the alignment layer of the electro-optical layer, for the reason that the inclusion of air bubbles can be suppressed during the formation of the EO layer.

[0065] The protective layer is preferably made of a flexible material that does not significantly deform, shrink, or stretch under pressure or under pressure and heat. For example, the cover film described in paragraphs

[0083] to

[0087] and

[0093] of JP-A-2006-259138 can be used as the protective layer. Specific examples of such a protective layer include polyolefin films such as polyethylene films and polypropylene films; polyester films such as polyethylene terephthalate films; cellulose triacetate films; polystyrene films; polycarbonate films, etc., and among these, polyolefin films are preferred, and polypropylene films are more preferred.

[0066] The thickness of the protective layer is not particularly limited, but is preferably 1 to 50 μm, more preferably 3 to 30 μm, and even more preferably 5 to 20 μm, from the viewpoints of ease of handling, versatility, etc. Here, the thickness of the protective layer is calculated as the average value when 100 points are measured at 1 cm intervals over an area of ​​10 cm × 10 cm, as in the case of the temporary support described above, using a pencil-type high-precision digital length measuring instrument PHA-13W manufactured by Tosei Engineering Co., Ltd., with an E-ST-100DB stand attached, and a MINICOM-M (Model E-M) as a display device.

[0067] In the present invention, the surface roughness Ra of the protective layer on the electro-optic layer side is preferably 50 nm or less, more preferably 25 nm or less, because this can further suppress the inclusion of air bubbles during the formation of the EO layer. The lower limit of the surface roughness Ra is not particularly limited, but from the viewpoint of manufacturing, it is preferably 1 nm or more. Here, the surface roughness Ra refers to a value measured by the following method. First, a three-dimensional optical profiler (New View 7300, manufactured by Zygo) is used to obtain a surface profile of the protective layer on the electro-optic layer side under the following conditions. The measurement and analysis software used is MetroPro ver. 8.3.2 Microscope Application. Next, the Surface Map screen is displayed in the analysis software (MetroPro ver. 8.3.2 Microscope Application), and histogram data is obtained on the Surface Map screen. Next, the arithmetic average roughness is calculated from the obtained histogram data and is taken as the surface roughness Ra. When the protective layer and the EO layer are in contact with each other, the protective layer is peeled off and the exposed peeled surface is used as the measurement surface to measure the surface roughness Ra. (Measurement conditions) Objective lens: 50x Zoom: 0.5x Measurement area: 1.00mm x 1.00mm (Analysis conditions) Removed: plane Filter: off Filter Type: average Remove spikes: on Spike Height (xRMS): 7.5

[0068] [Method for manufacturing an optical waveguide] The method for manufacturing an optical waveguide of the present invention includes a step of laminating the electro-optical layer of the transfer film of the present invention described above to an object to be laminated to form an optical waveguide. Here, the method for laminating to the object to be laminated is not particularly limited, and examples thereof include a method of laminating to an optical waveguide component such as a core layer or clad layer via a known pressure-sensitive adhesive. Note that, when the transfer film of the present invention described above has a protective layer, it is preferable to peel off the protective layer before laminating the electro-optical layer to the object to be laminated.

[0069] Furthermore, among the methods for producing an optical waveguide of the present invention, a production method according to a first aspect includes a method in which the electro-optic layer of the transfer film of the present invention described above is laminated as a cladding layer to the surface of a substrate having a patterned core layer (e.g., a Si layer) on the core layer side, and then the temporary support is peeled off, thereby producing a hybrid waveguide type optical waveguide. Note that the poling treatment applied to the electro-optic layer may be performed either before or after lamination of the electro-optic layer, as described above.

[0070] Furthermore, among the methods for manufacturing an optical waveguide of the present invention, a manufacturing method relating to a second aspect includes a method of manufacturing a polymer waveguide type optical waveguide by laminating an electro-optical layer of the transfer film of the present invention described above to the surface of a substrate having a cladding layer on the cladding layer side, then peeling off the temporary support, and then patterning the electro-optical layer (for example, dry etching using a resist) to form a core layer.

[0071] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

[0072] [Example 1] [Formation of Thermoplastic Resin Layer] A coating solution for a thermoplastic resin layer having the following composition was slot die coated onto a temporary support made of a polyethylene terephthalate film (width: 1610 mm, thickness: 75 μm), and dried for 3 minutes at 100° C. to form a thermoplastic resin layer having a thickness of 5 μm. The melt viscosity of the formed thermoplastic resin layer at 110° C. was 1000 Pa s.

[0073] -------------------------------------------------- Coating liquid for thermoplastic resin layer -------------------------------------------------- Binder A (listed below) 8.47 parts by mass 1-Methoxy-2-propyl acetate 3.47 parts by mass Binder B (listed below) 24.6 parts by mass Plasticizer: 2,2-bis[4-(methacryloxypolyethoxy)phenyl]propane (manufactured by Shin-Nakamura Kogyo Co., Ltd.) 5.40 parts by mass Surfactant 1: Megafac F-780-F (manufactured by Dainippon Ink and Chemicals, Inc.) 0.83 parts by weight Methyl ethyl ketone 42.6 parts by mass Methanol 13.5 parts by mass --------------------------------------------------

[0074] <Binder A> Aromatex FM601 (manufactured by Mitsui Chemicals, Inc., weight average molecular weight = 90,000, solid content concentration 21 mass%, methyl methacrylate / 2-ethylhexyl acrylate / benzyl methacrylate / methacrylic acid copolymer ((molar ratio = 55 / 11.7 / 4.5 / 28.2): 21 parts, methyl ethyl ketone: 26 parts, 1-methoxy-2-propyl acetate: 13 parts, methanol: 40 parts)

[0075] <Binder B> Arosset 7055 (manufactured by Nippon Shokubai Co., Ltd., weight average molecular weight = 8000, solid content concentration 41 mass%, styrene / acrylic acid copolymer (molar ratio 63 / 37): 41 parts, methyl ethyl ketone: 50 parts, 1-methoxy-2-propyl acetate: 9 parts)

[0076] [Formation of Orientation Layer] A coating liquid for orientation layer having the following composition was applied onto the formed thermoplastic resin layer using a slot die, and dried at 100° C. for 1 minute to form an orientation layer with a thickness of 0.5 μm.

[0077] ------------------------------------------------------------------ Coating liquid for alignment layer -------------------------------------------------- Polyvinyl alcohol (PVA205 (saponification rate = 88%); manufactured by Kuraray Co., Ltd.) 2.1 parts by mass Methanol 44 parts by mass Distilled water 53 parts by mass ------------------------------------------------------------------

[0078] [Formation of Electro-Optical Layer (EO Layer)] The laminate formed up to the alignment layer was cut into a 10 cm × 10 cm piece. An EO layer coating solution having the following composition was spin-coated at 400 rpm onto the alignment layer of the cut-out sample at 130°C for 30 seconds, and then dried to form an EO layer with a thickness of 1.8 μm. The melt viscosity of the formed EO layer at 110°C was 15,000 Pa s. The content of organic dye A contained in the formed EO layer was 9.8% by mass, and the degree of alignment was 0.60. The degree of alignment of liquid crystal compound A contained in the formed EO layer was 0.80.

[0079] ----------------------------------------------- EO layer coating solution -------------------------------------------------- ・0.050 g of the following organic dye A ・0.450 g of the following liquid crystal compound A ・0.012 g of the following alignment agent A ・4.490 g of chloroform ------------------------------------------------

[0080] Organic dye A (second-order molecular susceptibility: 1806 × 10 －３０ esu)

[0081] Liquid crystal compound A (weight average molecular weight: 12,000, the values ​​in the following formula represent the mass % of each repeating unit)

[0082] Alignment agent A (weight average molecular weight: 25,000, the values ​​in the following formula represent the mass % of each repeating unit)

[0083] [Formation of Protective Layer] A polypropylene protective layer (thickness: 12 μm, surface roughness: 15 nm) was pressure-bonded to the formed EO layer to prepare a transfer film (layer structure: temporary support / thermoplastic resin layer / alignment layer / EO layer / protective layer).

[0084] [Preparation of Optical Waveguide Members] The protective layer of the prepared transfer film was peeled off, and the exposed EO layer was attached to the ITO (Tin Oxide) sputtered glass substrate using a laminator (Hitachi Industries, Ltd. (Lamic II type)) under a linear pressure of 100 N / cm, a pressurized and heated condition of 110°C, and a conveying speed of 1 m / min. Thereafter, the polyethylene terephthalate film temporary support and the thermoplastic resin layer were peeled off and removed. Next, the obtained laminate (glass substrate / ITO / EO layer / alignment layer) was placed on a hot plate and treated by corona poling. Specifically, with a charging voltage of 6 kV applied at a distance of 10 mm from the EO layer, the EO layer was held at 50°C for 10 minutes, and then the EO layer was air-cooled with the charging voltage still applied. After cooling to 23°C over 10 minutes, the charging voltage was removed. Thereafter, the alignment layer was removed by washing with water to obtain a thin film (layer structure: glass substrate / ITO / EO layer) in which the organic dye was oriented in the thickness direction.

[0085] [Examples 2 to 13] Transfer films and thin films were prepared in the same manner as in Example 1, except that the thickness of the temporary support, the melt viscosity of the thermoplastic resin layer, the type or amount of organic dye, the type or amount of liquid crystal compound, the amount of alignment agent, or the type of solvent was changed to those shown in Table 1 below.

[0086] [Evaluation] [Thickness Variation] The thickness variation of the EO layer of the prepared thin film was evaluated using the following method and criteria. The results are shown in Table 1 below. Table 1 also shows the evaluation results of a thin film prepared by directly applying the EO layer coating solution used in each Example onto a glass substrate on which ITO had been sputtered. <Measurement Method> The thickness was measured using a surface roughness meter P-10 (manufactured by TENCOR Corporation). <Criteria> The height of 100 film surfaces at 1 cm intervals on the obtained thin film (11 cm x 11 m) was measured using a three-dimensional surface structure analysis microscope (manufacturer: ZYGO Corporation, model: New View 5022), and the percentage variation of the maximum or minimum spacer value relative to the average value was evaluated. C or higher is a practical level. A: The thickness variation of the EO layer was less than ±2.0%, which is extremely good. B: Good, with a variation in thickness of the EO layer of ±2.0% or more and less than ±3.0%. C: Fair, with a variation in thickness of the EO layer of ±3.0% or more and less than ±5.0%. D: Poor, with a variation in thickness of the EO layer of ±5.0% or more.

[0087] [Transferability] <Microbubbles> The prepared transfer film was laminated onto a 0.7 mm thick Si substrate (with 0.4 μm × 2000 μm Si convex lines on the Si substrate) at a lamination speed of 1 m / min and by changing the laminating roll temperature, and the transferability was evaluated based on the temperature at which transfer without defects was possible. The presence or absence of bubbles was observed under an optical microscope at 1000x magnification. A: The temperature at which transfer without bubbles was possible was less than 120°C. B: The temperature at which transfer without bubbles was possible was 120°C or more and less than 130°C. C: The temperature at which transfer without bubbles was possible was 130°C or more and less than 140°C. D: The temperature at which transfer without bubbles was possible was 140°C or more and less than 150°C. E: The temperature at which transfer without bubbles was possible was 150°C or more.

[0088] <Large bubbles> The prepared transfer film was laminated onto a 0.7 mm thick Si substrate (with 0.4 μm × 2000 μm Si convex lines on the Si substrate) at a lamination speed of 1 m / min and by changing the laminating roll temperature, and transferability was evaluated based on the temperature at which transfer was possible without bubble defects. The presence or absence of bubbles was observed under an optical microscope at 50x magnification. A: The temperature at which transfer was possible without bubbles was less than 120°C. B: The temperature at which transfer was possible without bubbles was 120°C or more and less than 130°C. C: The temperature at which transfer was possible without bubbles was 130°C or more and less than 140°C. D: The temperature at which transfer was possible without bubbles was 140°C or more and less than 150°C. E: The temperature at which transfer was possible without bubbles was 150°C or more.

[0089] [Electro-optical constants] The electro-optical constant (hereinafter also abbreviated as "r value") of the prepared thin film was determined as an index of nonlinear optical performance. The thin film obtained by electric field poling treatment was measured for the applied voltage dependence of the refractive index change at a wavelength of 1309 nm (measured at applied voltages of 0 V, 10 V, and 20 V) using a prism coupler device (Model 2010 / M manufactured by Metricon) and a coated prism (P-200C, a prism with a nickel coating on the prism surface), and the r value was calculated. The results are shown in Table 1 below. The r value was calculated using the following formula (2). In formula (2), δn / δV is the slope of the applied voltage dependence of the refractive index change, d is the thickness of the thin film (pm), and nTM is the refractive index of the thin film when a TM wave is incident and no voltage is applied. Table 1 below also shows the evaluation results of a thin film prepared by directly coating the EO layer coating solution used in each example on a glass substrate on which ITO had been sputtered.

[0090]

[0091] The structures of the organic dyes B to D and the liquid crystal compounds B to C in Table 1 above are shown below.

[0092] Organic dye B (second-order molecular susceptibility: 2851 × 10 －３０ esu)

[0093] Organic dye C (second-order molecular susceptibility: 349 × 10 －３０ esu)

[0094] Organic dye D (second-order molecular susceptibility: 262 × 10 －３０ esu)

[0095] Liquid crystal compound B (weight average molecular weight: 30,000, the values ​​in the following formula represent mass %)

[0096] liquid crystal compound C

[0097] The results shown in Table 1 indicate that when a thin film (layer structure: glass substrate / ITO / EO layer) was prepared using a transfer film (layer structure: temporary support / thermoplastic resin layer / alignment layer / EO layer / protective layer), the thickness variation was suppressed and the thin film exhibited a high electro-optic constant, compared to a thin film prepared by coating (Examples 1 to 13).

[0098] 10, 20 Transfer film 11 Temporary support 12 Orientation layer 13 Electro-optical layer 14 Thermoplastic resin layer 15 Protective layer

Claims

1. A transfer film for producing an optical waveguide member, comprising a temporary support, an alignment layer, and an electro-optical layer containing an organic dye, in that order.

2. The transfer film according to claim 1, further comprising a thermoplastic resin layer between the temporary support and the alignment layer.

3. The transfer film according to claim 2, wherein the melt viscosity of the thermoplastic resin layer at 110° C. is 200 to 3000 Pa·s.

4. The transfer film according to any one of claims 1 to 3, wherein the melt viscosity of the electro-optical layer at 110°C is 350 to 180,000 Pa·s.

5. The transfer film according to any one of claims 1 to 3, wherein the alignment layer is a rubbed alignment layer or a photoalignment layer.

6. The electro-optic layer has a second-order molecular susceptibility of 300×10 －３０ The transfer film according to any one of claims 1 to 3, comprising an organic dye having a viscosity of esu or more.

7. The transfer film according to any one of claims 1 to 3, wherein the organic dye contained in the electro-optical layer has a degree of orientation of 0.25 to 0.

95.

8. The transfer film according to any one of claims 1 to 3, wherein the electro-optical layer further comprises a liquid crystal compound.

9. The transfer film according to claim 8, wherein the degree of orientation of the liquid crystal compound contained in the electro-optical layer is 0.50 to 0.

95.

10. The transfer film according to any one of claims 1 to 3, further comprising a protective layer on the side of the electro-optical layer opposite to the alignment layer.

11. The transfer film according to claim 10, wherein the surface roughness Ra of the protective layer on the electro-optical layer side is 50 nm or less.

12. The transfer film of claim 10, wherein the protective layer is a polypropylene film.

13. The transfer film according to any one of claims 1 to 3, wherein the temporary support is a polymer film containing at least one material selected from the group consisting of polypropylene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, and triacetyl cellulose.

14. The transfer film according to claim 13, wherein the temporary support has a thickness of 5 to 200 μm.

15. The transfer film according to claim 2 or 3, wherein the thermoplastic resin layer has a thickness of 2 to 20 μm.

16. A method for producing an optical waveguide, comprising the step of laminating an electro-optical layer of a transfer film according to any one of claims 1 to 3 to an object to be laminated, thereby forming an optical waveguide.

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