Method for manufacturing optical resin wafer

Abstract

Provided is a method for manufacturing an optical resin wafer with improved productivity. This method for manufacturing an optical resin wafer includes an ingot preparation step for preparing an optical resin ingot, and a cutting step for cutting the optical resin ingot using a blade to obtain an optical resin wafer precursor, thereby making it possible to improve the productivity of the method for manufacturing the optical resin wafer.

Description

Optical resin wafer manufacturing method

[0001] The present invention relates to a method for manufacturing an optical resin wafer.

[0002] In the field of optical devices, there is a demand for resin materials due to reasons such as light weight and improved impact resistance.

[0003] Patent Document 1 describes a method for producing a thin film containing an organic polymer and having an area of ​​1 mm ２ or more, and the area is 1 mm ２ The patent document 1 also describes that "an object of the present disclosure is to provide an optical member that is lightweight and capable of transmitting optical information with high precision, a method for manufacturing the same, and an optical information transmission device that includes the optical member."

[0004] International Publication No. 2020 / 170801

[0005] A known method for manufacturing an optical resin wafer using a resin material is to pour the resin material into a mold, but there is room for improvement in productivity in this type of mold manufacturing.

[0006] The present invention provides a method for manufacturing an optical resin wafer with improved productivity.

[0007] According to the present invention, there is provided a method for manufacturing an optical resin wafer as follows.

[0008] 1. A method for producing an optical resin wafer, comprising an ingot preparation step of preparing an optical resin ingot, and a cutting step of cutting the optical resin ingot with a blade to obtain an optical resin wafer precursor. 2. A method for producing an optical resin wafer according to 1., wherein the cutting in the cutting step is performed using at least one saw selected from the group consisting of a wire saw and a blade saw. 3. A method for producing an optical resin wafer according to 2., wherein the cutting in the cutting step is performed using a multi-wire saw or a multi-blade saw to obtain a plurality of optical resin wafer precursors at once. 4. A method for producing an optical resin wafer, according to 2., wherein the temperature of the cut portion of the optical resin ingot in the cutting step is set to a temperature higher than the glass transition temperature Tgｉ When (Tg ｉ 4. The method for producing an optical resin wafer according to any one of 1. to 3., wherein the temperature at the cut portion of the optical resin ingot in the cutting step is 0°C or higher. 5. The method for producing an optical resin wafer according to 4., wherein the temperature at the cut portion of the optical resin ingot in the cutting step is 0°C or higher. 6. The method for producing an optical resin wafer according to any one of 1. to 5., wherein the optical resin ingot in the cutting step is fixed to a fixing table with an adhesive. 7. The method for producing an optical resin wafer according to 6., wherein the optical resin wafer precursor or the optical resin ingot fixed to the fixing table is peeled off by reducing the adhesive strength of the adhesive with an external stimulus. 8. The method for producing an optical resin wafer according to any one of 1. to 7., further comprising a processing step of performing at least one processing selected from the group consisting of notching, burring, beveling, cutting, grinding, polishing, and heating on the optical resin wafer precursor to obtain an optical resin wafer. 9. A method for producing an optical resin wafer according to any one of 1. to 8., wherein the optical resin wafer contains at least one selected from the group consisting of (thio)urethane-based optical resins, epoxy-based optical resins, polycarbonate-based optical resins, episulfide-based optical resins, allyl carbonate-based optical resins, nylon-based optical resins, polyamide-based optical resins, and polyimide-based optical resins. 10. A method for producing an optical resin wafer according to any one of 1. to 9., wherein the refractive index of the optical resin wafer is 1.47 or more. 11. A method for producing an optical resin wafer according to any one of 1. to 10., wherein the cure shrinkage rate A of the curable composition, which is a raw material for the optical resin ingot, calculated by the following formula (x) is 15% or less. A=(V ０ -V １ ) / V ０ × 100 (x) A: Curing shrinkage rate [%] V ０ : Volume of the curable composition (before curing) V １: Volume of the optical resin ingot (after hardening) 12. A method for manufacturing an optical resin wafer according to any one of 1. to 11., wherein the average thickness of the optical resin wafer is 0.1 mm to 3.0 mm. 13. A method for manufacturing an optical resin wafer according to any one of 1. to 12., wherein the diameter of the optical resin wafer is 50 mm to 350 mm. 14. A method for manufacturing an optical resin wafer according to any one of 1. to 13., wherein the flatness of the optical resin wafer is 350 μm or less.

[0009] According to the present invention, a method for manufacturing an optical resin wafer with improved productivity can be provided.

[0010] It is a figure which shows typically an example of a manufacturing method of the optical resin wafer of this embodiment. It is a figure which shows typically an example of a manufacturing method of the optical member of this embodiment. It is a cross-sectional view which shows typically an example of an optical information transmission device which uses the optical member of this embodiment.

[0011] Hereinafter, embodiments of the present invention will be described.

[0012] 1. Method for Manufacturing an Optical Resin Wafer Hereinafter, a method for manufacturing an optical resin wafer according to this embodiment will be described.

[0013] 1 is a diagram showing a schematic diagram of an example of a process flow of the method for manufacturing an optical resin wafer of this embodiment. The method for manufacturing an optical resin wafer of this embodiment includes an ingot preparation step of preparing an optical resin ingot 2, and a cutting step of cutting the optical resin ingot 2 of this embodiment with a blade to obtain an optical resin wafer precursor. The method for manufacturing an optical resin wafer of this embodiment includes, for example, an ingot preparation step (hereinafter sometimes abbreviated as "ingot preparation step") of connecting multiple optical resin molded bodies 1 to prepare an optical resin ingot 2, and a cutting step (hereinafter sometimes abbreviated as "cutting step") of cutting the optical resin ingot 2 with a multi-wire saw 3 to obtain multiple optical resin wafer precursors at once. In addition, a multi-blade saw, a peripheral blade horizontal grinding device, or an internal blade grinding device may be used instead of the multi-wire saw, although cutting loss will be slightly increased.

[0014] As a result of extensive research into the productivity of optical resin wafers, the inventors discovered that by preparing the optical resin as an ingot and cutting it with a blade, productivity can be dramatically improved compared to a manufacturing method in which wafers are formed one by one using a mold.

[0015] In this embodiment, for example, a plurality of optical resin molded bodies 1 made of a thiourethane-based optical resin are joined together to prepare an optical resin ingot 2. Note that, even if no specific work is performed in the ingot preparation step, the optical resin ingot can be considered to be prepared as long as the optical resin ingot is ready to be used in the cutting step.

[0016] The prepared optical resin ingot 2 is fixed, for example, via a hot-melt epoxy adhesive (not shown) to a fixing table (not shown) in an apparatus including a multi-wire saw 3, and the fixed optical resin ingot 2 is cut by the multi-wire saw 3 to obtain a plurality of optical resin wafer precursors at once. Note that, for example, the temperature of the cut portion of the optical resin ingot during cutting is set to a temperature equal to or higher than the glass transition temperature Tg ｉ When (Tg ｉ The temperature is controlled to be below −20°C and above 0°C.

[0017] The optical resin wafer precursor fixed to the fixing table is heated to a temperature higher than the melting or melting point of the hot-melt epoxy adhesive and lower than the glass transition temperature (Tg ｉ The substrates are heated to a temperature of −10° C. or lower and then peeled off from the fixing base.

[0018] The obtained optical resin wafer precursor is subjected to, for example, a deburring process to remove burrs remaining on the outer periphery, and a notch process to form a notch at the end of the optical resin wafer precursor, thereby obtaining an optical resin wafer made of a (thio)urethane-based optical resin. An orientation flat may be used instead of the notch.

[0019] The obtained optical resin wafer precursor is subjected to, for example, burr processing to remove burrs remaining on the outer periphery, notch processing to form a notch at the end of the optical resin wafer precursor, polishing processing to polish the surface of the optical resin wafer precursor, and heating processing to heat the optical resin wafer precursor, thereby obtaining an optical resin wafer.

[0020] The method for preparing the optical resin ingot in the ingot preparation step of this embodiment is not particularly limited, and the ingot may be produced by the ingot manufacturer or may be obtained from another supplier. The method for producing the optical resin ingot is also not particularly limited, and includes a method of casting a curable composition, which is a raw material for the optical resin wafer, into a mold for producing the ingot and curing it to obtain the optical resin ingot.

[0021] The cutting method in the cutting step of this embodiment is not particularly limited, but is preferably carried out using at least one selected from the group consisting of a wire saw and a blade saw. This allows an optical resin wafer precursor with reduced thickness variation to be obtained, thereby improving the polishing accuracy in the polishing step and further improving the smoothness of the optical resin wafer. Furthermore, the cutting method in the cutting step of this embodiment is not particularly limited, but is more preferably carried out using a multi-wire saw or a multi-blade saw to obtain multiple optical resin wafer precursors at once, and is particularly preferably carried out using a multi-wire saw to obtain multiple optical resin wafer precursors at once. This allows multiple optical resin wafer precursors with reduced thickness variation to be obtained at once, and the thickness can be adjusted to the minimum required processing allowance, thereby further improving the manufacturing efficiency of optical resin wafers.

[0022] The cutting conditions in the cutting step of this embodiment are not particularly limited. However, from the viewpoint of suppressing softening of the optical resin wafer, the temperature of the cut portion of the optical resin ingot is set to a temperature higher than the glass transition temperature Tg ｉ When (Tg ｉ It is preferable that the temperature is controlled to be equal to or lower than (Tg −20° C.). ｉIt is more preferable that the temperature is controlled to be equal to or lower than (Tg −30)°C. ｉ It is more preferable that the temperature of the cut portion of the optical resin ingot is controlled to a temperature of 0°C or higher. As a method for controlling the temperature of the cut portion of the optical resin ingot, a method of controlling the temperature using a wafer cutting slurry can be mentioned.

[0023] Although other conditions in the cutting process of this embodiment are not particularly limited, it is preferable that the optical resin ingot is fixed to a fixing table with an adhesive before cutting, which can suppress the positional deviation of the optical resin ingot during the cutting process and enable the production of high-quality optical resin wafers.

[0024] The optical resin wafer precursor fixed to the fixing table by an adhesive is preferably peeled off by reducing the adhesive strength of the adhesive using an external stimulus, such as heat, light, or dissolution (using a solvent, organic solvent, or water). If the adhesive strength of the adhesive can be reduced by heat or light, the optical resin wafer precursor can be easily peeled off, and since no unnecessary force is applied to the optical resin wafer during peeling, deformation of the optical resin wafer during peeling is suppressed. The type of light that reduces the adhesive strength of the adhesive includes, for example, ultraviolet light, visible light, and infrared light, and is preferably ultraviolet light. By using ultraviolet light, the adhesive strength can be reduced with short-term irradiation, and the temperature rise in the irradiated area can be suppressed.

[0025] The adhesive of this embodiment is preferably, for example, a so-called hot-melt adhesive, which softens when heated and thereby loses adhesive strength. Specific examples of such adhesives include epoxy adhesives, ethylene vinyl acetate copolymer adhesives, olefin adhesives, elastomer adhesives, polyurethane adhesives, polyamide adhesives, and polyester adhesives. From the viewpoint of adhesive strength, hot-melt epoxy adhesives are particularly preferred. An example of a hot-melt epoxy adhesive is Aquawax Water Wash Type, manufactured by Nikka Seiko Co., Ltd.

[0026] The melting temperature of the adhesive of this embodiment is preferably (Tg of optical resin ingot - 10) ° C. or less, more preferably (Tg of optical resin ingot - 20) ° C. or less, even more preferably (Tg of optical resin ingot - 25) ° C. or less, and even more preferably (Tg of optical resin ingot - 30) ° C. or less.

[0027] The optical resin wafer precursor fixed to the fixing table may be peeled off by cutting the fixed portion between the optical resin wafer precursor and the fixing table.

[0028] This embodiment preferably includes a processing step of obtaining an optical resin wafer by performing at least one process selected from the group consisting of notching, burring, beveling, cutting, grinding, polishing, and heating.

[0029] Notch processing is a process for forming a notch, which serves as a mark for indicating the orientation of an optical resin wafer. The equipment and conditions used for notch processing are not particularly limited, and known equipment and conditions can be appropriately adopted for processing.

[0030] Deburring is a process of removing burrs such as protrusions that occur on the outer periphery of the optical resin wafer precursor. The equipment and conditions used for deburring are not particularly limited, and known equipment and conditions can be appropriately adopted for processing.

[0031] Beveling is a process of cutting off the corners of the outer periphery of the optical resin wafer precursor and rounding (chamfering) it in the thickness direction. The apparatus and conditions used for beveling are not particularly limited, and known apparatuses and conditions can be appropriately adopted for processing.

[0032] Grinding is a process of grinding the surface of the optical resin wafer precursor to ensure flatness, etc. Polishing is a process of polishing the surface of the optical resin wafer precursor to ensure flatness, etc. The methods and conditions of the grinding and polishing processes are not particularly limited, and for example, the methods described in paragraphs

[0047] to

[0062] of WO 2020 / 170801 can be appropriately adopted. This can further reduce the thickness unevenness of the optical resin wafer, and further improve the flatness and smoothness.

[0033] Heat processing is a process of heating a cured product for the purpose of alleviating internal stress of the optical resin wafer precursor. Heating activates the movement of the molecules that make up the optical resin wafer precursor, removing distortion in the optical resin wafer precursor, and thereby flattening the optical resin wafer. The heating temperature in the heat processing is preferably 60°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, even more preferably 90°C or higher, and even more preferably 100°C or higher, from the viewpoint of further flattening the optical resin wafer. Furthermore, based on the glass transition temperature (Tg) of the optical resin that is the raw material for the optical resin wafer, the temperature is preferably Tg-20°C or higher, more preferably Tg-10°C or higher, even more preferably Tg or higher, even more preferably Tg+10°C or higher, even more preferably Tg+20°C or higher, even more preferably Tg+30°C or higher, even more preferably Tg+40°C or higher, and even more preferably Tg+50°C or higher. If the thermal degradation of the optical resin wafer is within an acceptable range, the temperature may be, for example, 200°C or lower. In addition, when determining the heating processing temperature, it is advisable to refer to the temperature dependence of the storage modulus and loss modulus by viscoelasticity measurement. In addition, in the heating processing, from the viewpoint of further suppressing warpage, pressure may be further applied. Specifically, pressure may be applied by sandwiching the optical resin wafer of this embodiment between flat plates and pressing.

[0034] From the viewpoint of improving optical properties, the material of the optical resin wafer produced in this embodiment preferably contains at least one selected from the group consisting of (thio)urethane-based optical resins, epoxy-based optical resins, polycarbonate-based optical resins, episulfide-based optical resins, allyl carbonate-based optical resins (preferably diallyl carbonate-based optical resins), nylon-based optical resins, polyamide-based optical resins, and polyimide-based optical resins, more preferably contains a (thio)urethane-based optical resin, and particularly preferably contains a thiourethane resin.

[0035] The components of the curable composition used in this embodiment are appropriately selected depending on the material of the target optical resin wafer. When the material of the target optical resin wafer is a (thio)urethane-based optical resin, the curable composition can be obtained by polycondensing an iso(thio)cyanate compound and a bifunctional or higher active hydrogen compound (for example, a polythiol compound, a polyol compound, etc.).

[0036] Examples of the iso(thio)cyanate compound used in the curable composition of the present embodiment include hexamethylene diisocyanate, pentamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, phenylene diisocyanate, and 4,4'-diphenylmethane diisocyanate.

[0037] Examples of the polythiol compound used in the curable composition of the present embodiment include pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), bis(2-mercaptoethyl)sulfide, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto mercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 2,5-dimercaptomethyl-1,4-dithiane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithietane, ethylene glycol bis(3-mercaptopropionate), and the like.

[0038] Examples of the polyol compound used in the curable composition of the present embodiment include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,5-pentanediol, 2,4-pentanediol, and 2-methyl-2,4-pentanediol. linear or branched aliphatic alcohols such as 1,2-cyclopentanediol, 1,3-cyclopentanediol, 3-methyl-1,2-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 4,4'-bicyclohexanol, and 1,4-cyclohexanedimethanol; and the like.

[0039] The average thickness of the optical resin wafer produced in this embodiment can be adjusted appropriately according to the use of the optical resin wafer, but is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, and is preferably 3.0 mm or less, more preferably 2.0 mm or less, even more preferably 1.0 mm or less. Note that the average thickness of the optical resin wafer produced in this embodiment is the arithmetic mean of the thickness at a point 5 mm from the edge of the hole of the optical resin wafer toward the outer periphery and the thickness at a point 5 mm from the outer periphery toward the center of the optical resin wafer.

[0040] The diameter of the optical resin wafer manufactured in this embodiment can be adjusted appropriately according to the use of the optical resin wafer, but from the viewpoint of obtaining more optical components from one optical resin wafer, it is preferably 50 mm or more, more preferably 70 mm or more, even more preferably 80 mm or more, even more preferably 100 mm or more, even more preferably 120 mm or more, even more preferably 140 mm or more, and may be, for example, 350 mm or less. Here, the larger the diameter of the optical resin wafer, the greater the force that the resin composition is drawn toward the center of the cavity space of the mold due to the curing shrinkage of the resin composition, and the flatness of the optical resin wafer is likely to decrease, but according to this embodiment, even if the diameter of the optical resin wafer is above the above lower limit, the flatness can be improved.

[0041] The optical resin wafer manufactured in this embodiment is used as a material for optical products, so it may be required to improve flatness and smoothness and reduce thickness unevenness.The preferred ranges of Bow, which is the index of flatness required for the optical resin wafer manufactured in this embodiment, TTV, which is the index of thickness unevenness, and surface roughness Ra, which is the index of smoothness, are as follows, for example:

[0042] The flatness of the optical resin wafer produced in this embodiment is preferably 350 μm or less, more preferably 300 μm or less, even more preferably 250 μm or less, even more preferably 200 μm or less, even more preferably 150 μm or less, even more preferably 100 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, even more preferably 30 μm or less, and may be, for example, 0.01 μm or more, 0.1 μm or more, 1 μm or more, or 10 μm or more.

[0043] The flatness / planarity of the optical resin wafer manufactured in this embodiment refers to, for example, the bow of the optical resin wafer, and can be measured using an ultra-high precision three-dimensional measuring machine. For example, it can be measured under the following conditions. In this embodiment, bow is the amount that represents the distance from the reference (standard) surface at the center of the wafer when the wafer is held in its natural state without vacuum suction. Apparatus: UA3P (manufactured by Panasonic Production Engineering Co., Ltd.) Measurement area: Circular area of ​​±30 mm in the X and Y directions from the center of the optical resin wafer Alternatively, the difference between the maximum and minimum values ​​of the measurement (PV) or WARP may simply be used as an index.

[0044] The thickness unevenness TTV of the optical resin wafer manufactured in this embodiment is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 2 μm or less, and even more preferably 1 μm or less, and the lower limit of the thickness unevenness TTV is not particularly limited, but may be, for example, 0.01 μm or more, or 0.1 μm or more. In this embodiment, TTV is the difference between the maximum and minimum values ​​of the thickness (distance from the back surface reference plane) when the wafer is suction-fixed.

[0045] The surface roughness Ra of the optical resin wafer manufactured in this embodiment is preferably 10 nm or less, more preferably 5 nm or less, even more preferably 2 nm or less, and even more preferably 1 nm or less, and the lower limit of the surface roughness Ra is not particularly limited, but may be, for example, 0.01 nm or more, or 0.1 nm or more. The surface roughness Ra of the optical resin wafer can be determined by measurement in accordance with Japanese Industrial Standards JIS B 0601:2013.

[0046] The refractive index of the optical resin wafer manufactured in this embodiment is preferably 1.47 or more, more preferably 1.49 or more, even more preferably 1.51 or more, and even more preferably 1.53 or more, from the viewpoint of being able to reduce the thickness of the optical resin wafer while improving the optical properties of the optical resin wafer, and may be, for example, 1.90 or less, for example, 1.80 or less, for example, 1.70 or less. The refractive index of the optical resin wafer can be determined in accordance with Japanese Industrial Standards JIS K-0062:1992, by measurement at a temperature of 25 ° C. and a wavelength of 587.6 nm.

[0047] In the optical resin wafer manufactured in this embodiment, from the viewpoint of being able to further flatten the optical resin wafer, the cure shrinkage rate A of the curable composition that is the raw material of the optical resin ingot, calculated by the following formula (x), is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less. The cure shrinkage rate A of the optical resin wafer can be determined by measurement in accordance with Japanese Industrial Standards JIS K-6941-2-4:2014. A=(V ０ -V １ ) / V ０ × 100 (x) A: Curing shrinkage rate [%] V ０ : Volume of the curable composition (before curing) V １ : Volume of optical resin ingot (after hardening)

[0048] The linear expansion coefficient a of the optical resin wafer manufactured in this embodiment ｗ is preferably 10 x 10 －６ / °C or more, more preferably 20 x 10 －６ / °C or more, more preferably 30 x 10 －６ / °C or more, more preferably 40 x 10 －６ / °C or more, and preferably 250 x 10 －６ / °C or less, more preferably 200 × 10 －６ / °C or less, more preferably 150 x 10 －６ / °C or less, more preferably 100 x 10 －６ / °C or less, more preferably 80 x 10 －６ / °C or less. This makes it possible to further improve the flatness of the optical resin wafer. ｗ was measured in accordance with JIS K-7197:2012 under the condition of a temperature rise rate of 5°C / min from 25°C to 150°C. The linear expansion coefficient a ｗ In general, the linear expansion coefficient a is preferably small in order to reduce the influence of thermal expansion when performing composite processing with inorganic materials, forming a laminate, precision processing (patterning, etc.) in which a heating process is combined, etc. ｗ is preferably 30 x 10 －６ / °C or less, more preferably 20 x 10 －６ / °C or less, more preferably 10 x 10 －６ / °C or less, and more preferably 1 x 10 －６ / °C or less. Furthermore, when performing microfabrication (VHG, VBG, etc.) that applies holograms, composites with organic materials or laminates are formed, so the closer the linear expansion coefficient to that of the laminated organic material, the better. This is expected to suppress the occurrence of warping during or after processing, suppress the occurrence of warping due to temperature changes in the processed body, and improve processing accuracy during or after processing.

[0049] The curing conditions in the curing step of this embodiment should be appropriately selected depending on the material of the target optical resin wafer, but from the viewpoint of suppressing thermal runaway and convection due to reaction heat, the curing temperature is, when the glass transition temperature (Tg) of the optical resin that is the raw material of the optical resin wafer is used as the reference, preferably glass transition temperature (Tg) + 10°C or higher, more preferably glass transition temperature (Tg) + 15°C or higher, even more preferably glass transition temperature (Tg) + 20°C or higher, and preferably glass transition temperature (Tg) + 40°C or lower, more preferably glass transition temperature (Tg) + 35°C or lower, and even more preferably glass transition temperature (Tg) + 30°C or lower. Furthermore, a specific curing temperature is usually 110°C to 140°C.

[0050] In order to prevent thermal runaway and convection caused by the heat of reaction, the temperature rise time in the curing step of this embodiment is preferably 1 hour or longer, more preferably 1.1 hours or longer, even more preferably 1.2 hours or longer, even more preferably 1.8 hours or longer, even more preferably 1.9 hours or longer, and even more preferably 2 hours or longer. When the amount of optical resin is large, the temperature rise time may be 12 hours or longer, 14 hours or longer, 16 hours or longer, 20 hours or longer, 22 hours or longer, or 24 hours or longer. When the amount of optical resin is even larger, the temperature rise time may be 24 hours or longer, 26 hours or longer, 28 hours or longer, 44 hours or longer, 46 hours or longer, or 48 hours or longer.

[0051] The curing temperature holding time in the curing step of the present embodiment is preferably 1 hour or longer, more preferably 1.1 hours or longer, even more preferably 1.2 hours or longer, even more preferably 1.8 hours or longer, even more preferably 1.9 hours or longer, and even more preferably 2 hours or longer, from the viewpoint of suppressing thermal runaway and convection due to the heat of reaction.

[0052] In order to reduce unreacted materials, the temperature-lowering time in the curing step of this embodiment is preferably 1 hour or longer, more preferably 1.1 hours or longer, even more preferably 1.2 hours or longer, even more preferably 1.8 hours or longer, even more preferably 1.9 hours or longer, and even more preferably 2 hours or longer. When the amount of optical resin is large, the temperature-lowering time may be 12 hours or longer, 14 hours or longer, 16 hours or longer, 20 hours or longer, 22 hours or longer, or 24 hours or longer. When the amount of optical resin is even larger, the temperature-lowering time may be 24 hours or longer, 26 hours or longer, 28 hours or longer, 44 hours or longer, 46 hours or longer, or 48 hours or longer.

[0053] The optical resin wafer manufactured in this embodiment can be used, for example, in an optical information transmission device. Examples of optical information transmission devices include wearable displays that display virtual reality (VR), augmented reality (AR), etc. When the optical resin wafer manufactured in this embodiment is used in an optical information transmission device, improved flatness and smoothness and reduced thickness unevenness of the optical resin wafer are more required than when used for other purposes. As described above, according to this embodiment, it is possible to obtain a wafer with improved flatness and smoothness and reduced thickness unevenness, so the optical resin wafer obtained in this embodiment is suitable for use in an optical information transmission device.

[0054] 2. Optical Resin Wafer The optical resin wafer of this embodiment will be described below.

[0055] The optical resin wafer of this embodiment is obtained by the manufacturing method of the optical resin wafer of this embodiment.

[0056] 3. Method for Manufacturing Optical Member Hereinafter, a method for manufacturing the optical member of this embodiment will be described.

[0057] 2 is a diagram schematically showing an example of a method for manufacturing an optical member according to the present embodiment. The method for manufacturing an optical member according to the present embodiment includes a step of obtaining a plurality of optical members 5 from the optical resin wafer 4 according to the present embodiment.

[0058] The optical member 5 of this embodiment may be, for example, an optical lens, a light guide plate, a filter, or an optical switch.

[0059] 4. Optical Member The optical member of this embodiment will now be described.

[0060] The optical member of this embodiment is obtained by the method for manufacturing an optical member of this embodiment.

[0061] The optical member of this embodiment can be used, for example, in an optical information transmission device. The optical information transmission device has been described above. An optical information transmission device using the optical member of this embodiment will be described with reference to FIG. 3. The optical information transmission device 20 includes a light irradiation unit 11 and the optical member 10 of this embodiment. Light 12 generated from the light irradiation unit 11 is reflected by the optical member 10 of this embodiment, and the reflected light is irradiated onto the user's eye 13. As a result, the light generated from the light irradiation unit 11 is recognized by the user wearing the optical information transmission device 20.

[0062] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0063] This application claims priority based on Japanese Patent Application No. 2023-221606, filed December 27, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0064] The present invention may also take the following forms. [1] A method for manufacturing an optical resin wafer, comprising step A of cutting an optical resin ingot by a cutting method using a blade to obtain a plurality of optical resin wafer precursors. [2] The cutting method includes at least one cutting method selected from a wire saw and a blade saw. [3] A method for manufacturing an optical resin wafer according to [1] or [2], further comprising step B of polishing the optical resin wafer precursor. [4] A method for manufacturing an optical resin wafer according to [1] or [2], wherein the optical resin ingot is fixed to a fixing table with a fixing agent. [5] A method for manufacturing an optical resin wafer according to [4], further comprising step C of applying an external stimulus to reduce the fixing force of the fixing agent and peeling the optical resin wafer precursor from the fixing table. [6] A method for manufacturing an optical resin wafer according to [1] or [2], wherein in step A, the optical resin ingot is cut by at least one cutting method selected from a multi-wire saw consisting of a plurality of wires and a multi-blade saw consisting of a plurality of blades to simultaneously obtain a plurality of optical resin wafer precursors. [7] The method for producing an optical resin wafer according to [1] or [2], wherein in the step A, the temperature of the cut portion is (T-20)°C or lower, where T is the glass transition temperature of the optical resin ingot. [8] The method for producing an optical resin wafer according to [1] or [2], wherein in the step A, the temperature of the cut portion is 0°C or higher. [9] The method for producing an optical resin wafer according to [1] or [2], wherein the optical resin wafer contains one or more resins selected from the group consisting of (thio)urethane-based optical resins, epoxy-based optical resins, polycarbonate-based optical resins, episulfide-based optical resins, allyl carbonate-based optical resins, nylon-based optical resins, polyamide-based optical resins, and polyimide-based optical resins.

[10] The method for producing an optical resin wafer according to [1] or [2], wherein the thickness of the optical resin wafer is 0.1 mm or more and 3.0 mm or less.

[11] The method for producing an optical resin wafer according to [1] or [2], wherein the diameter of the optical resin wafer is 50 mm or more and 350 mm or less.

[12] The method for producing an optical resin wafer according to [1] or [2], wherein the flatness of the optical resin wafer is 350 μm or less.

[13] The method for producing an optical resin wafer according to [1] or [2], wherein the refractive index of the optical resin wafer at a temperature of 25°C and a wavelength of 587.6 nm is 1.47 or more in accordance with JIS K-0062: 1992.

[14] The method for producing an optical resin wafer according to [1] or [2], further comprising a step E of flattening the optical resin wafer by heating.

[0065] REFERENCE SIGNS LIST 1 Optical resin molded body 2 Optical resin ingot 3 Multi-wire saw 4 Optical resin wafer 5 Optical member 10 Optical member 11 Light irradiation unit 12 Light 13 Eye 20 Optical information transmission device

Claims

1. An ingot preparation step of preparing an optical resin ingot, and a cutting step of cutting the optical resin ingot with a blade to obtain a precursor of an optical resin wafer, a method for manufacturing an optical resin wafer including the steps.

2. The method for manufacturing an optical resin wafer according to claim 1, wherein the cutting in the cutting step is performed using at least one selected from the group consisting of a wire saw and a blade saw.

3. The method for manufacturing an optical resin wafer according to claim 2, wherein the cutting in the cutting step is performed using a multi-wire saw or a multi-blade saw, and a plurality of optical resin wafer precursors are obtained at once.

4. The temperature of the cut portion of the optical resin ingot in the cutting step is a temperature that is (Tg ｉ - 20) °C or lower when the glass transition temperature of the resin of the optical resin ingot is Tg ｉ . The method for manufacturing an optical resin wafer according to claim 1.

5. The method for manufacturing an optical resin wafer according to claim 4, wherein the temperature of the cut portion of the optical resin ingot in the cutting step is 0 °C or higher.

6. The method for manufacturing an optical resin wafer according to claim 1, wherein the optical resin ingot in the cutting step is fixed to a fixing table with an adhesive.

7. The method for manufacturing an optical resin wafer according to claim 6, wherein the peeling of the optical resin wafer precursor or the optical resin ingot fixed to the fixing table is performed by reducing the adhesive force of the adhesive by an external stimulus.

8. The method for manufacturing an optical resin wafer according to claim 1, further including a processing step of performing at least one type of processing selected from the group consisting of notch processing, burr processing, beveling processing, cutting processing, grinding processing, polishing processing, and heat processing on the optical resin wafer precursor to obtain an optical resin wafer.

9. The method for manufacturing an optical resin wafer according to claim 1, wherein the optical resin wafer contains at least one selected from the group consisting of (thio)urethane-based optical resins, epoxy-based optical resins, polycarbonate-based optical resins, episulfide-based optical resins, allyl carbonate-based optical resins, nylon-based optical resins, polyamide-based optical resins, and polyimide-based optical resins.

10. The method for manufacturing an optical resin wafer according to claim 1, wherein the refractive index of the optical resin wafer is 1.47 or higher.

11. The method for manufacturing an optical resin wafer according to claim 1, wherein the curing shrinkage rate A of the curable composition, which is the raw material of the optical resin ingot, calculated by the following formula (x) is 15% or less. A = (V ０ - V １ ) / V ０ × 100 (x) A: Curing shrinkage rate [%] V ０ : Volume of the curable composition (before curing) V １ : Volume of the optical resin ingot (after curing) 12. The method for manufacturing an optical resin wafer according to claim 1, wherein the average thickness of the optical resin wafer is 0.1 mm to 3.0 mm.

13. The method for manufacturing an optical resin wafer according to claim 1, wherein the diameter of the optical resin wafer is 50 mm to 350 mm.

14. The method for manufacturing an optical resin wafer according to claim 1, wherein the flatness of the optical resin wafer is 350 µm or less.

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