Method for producing optical member

Abstract

To provide a method for producing an optical member that is less affected by shrinkage and has improved mass productivity.SOLUTION: A method for producing an optical member which is composed of a quartz sintered body, includes: a compacting step of pressing a quartz precursor to obtain a compacted body; and a firing step of firing the compacted body to obtain the quartz sintered body, wherein an average particle diameter of the quartz precursor is 30 μm or less.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an optical member. [Background technology]

[0002] Long-life LED light sources in the short wavelength range (for example, wavelengths of 350 nm or less) have been developed and are being used in a variety of fields, including sterilization, medical applications, and semiconductor processing. The market is expanding rapidly, and the development of highly efficient LED light sources is progressing. Demand is also increasing for optical components that can be used in this wavelength range.

[0003] Generally, quartz glass is a material with high light transmittance in the short wavelength range, and for example, it is given a lens shape to improve the output efficiency of LED light sources. The manufacturing and processing of such lens-shaped quartz glass is not suitable for mass production, and production costs tend to be high. Therefore, methods for producing sintered quartz glass from quartz glass powder have been investigated as a method for manufacturing quartz glass with improved mass productivity. For example, Patent Document 1 proposes a method (gel casting method) in which a molded body is produced by casting a quartz slurry into a mold, and then the molded body is fired to obtain a quartz sintered body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 131668 Summary of the Invention [Problem to be solved by the invention]

[0005] In the gel-casting method, a large amount of binder and water is added to silica glass powder to obtain a silica slurry. Therefore, the silica slurry tends to shrink significantly during the drying and firing processes after casting, which can lead to problems such as cracks in the sintered silica compact and difficulty in controlling its shape. The impact of shrinkage is particularly significant when manufacturing minute optical components that require dimensional precision.

[0006] In view of the above, an object of the present invention is to provide a method for manufacturing an optical member that is less affected by shrinkage and has improved mass productivity. [Means for solving the problem]

[0007] A manufacturing method of an optical member according to aspect 1 is a manufacturing method of an optical member, in which the optical member is made of a quartz sintered body, and includes a pressing step of pressing a quartz precursor to obtain a green compact, and a firing step of firing the green compact to obtain a quartz sintered body, wherein the average particle size of the quartz precursor is 30 μm or less.

[0008] A method for producing an optical member according to aspect 2 is a method for producing an optical member, the optical member being made of a quartz sintered body and having lens portions, and including a pressing step of pressing a quartz precursor to obtain a green compact having a plurality of lens portions, and a firing step of firing the green compact to obtain a quartz sintered body, wherein the average particle size of the quartz precursor is 30 μm or less.

[0009] The method for producing an optical member according to the third aspect, in addition to the first or second aspect, preferably further comprises a singulating step of singulating the quartz sintered body.

[0010] In the method for producing an optical member of Aspect 4, in any one of Aspects 1 to 3, the quartz precursor preferably contains quartz powder.

[0011] In the method for producing an optical member of aspect 5, in accordance with aspect 4, the quartz powder is preferably substantially spherical.

[0012] In the method for producing an optical member of aspect 6, in accordance with aspect 4, it is preferable that the average particle size of the quartz powder is 1000 nm or less.

[0013] In the method for producing an optical member of aspect 7, in any one of aspects 1 to 6, the quartz precursor is preferably made of synthetic quartz.

[0014] The method for producing an optical member according to aspect 8 is any one of aspects 1 to 7, wherein the quartz sintered body preferably has a Na2O+K2O content of 150 mass ppm or less, a TiO2 content of less than 10 mass ppm, and an Fe2O3 content of 100 mass ppm or less.

[0015] A ninth aspect of the method for producing an optical member is any one of the first to eighth aspects, wherein in the powder compacting step, the surface roughness Ra of the pressing die is preferably 1 μm or less.

[0016] A tenth aspect of the method for producing an optical member is any one of the first to ninth aspects, and it is preferable that the firing temperature in the firing step is lower than 1400°C.

[0017] In the method for producing an optical member of an eleventh aspect, in any one of the first to tenth aspects, it is preferable that the quartz sintered body has a shrinkage rate of 50% or less relative to the green compact.

[0018] A twelfth aspect of the method for producing an optical member is any one of the first to eleventh aspects, wherein the length of the quartz sintered body is preferably 10 mm or more.

[0019] A thirteenth aspect of the method for producing an optical member is any one of the first to twelfth aspects, wherein the optical member has a light transmittance of 40% or more at a wavelength of 250 nm when the optical member has a thickness of 1 mm.

[0020] A fourteenth aspect of the method for producing an optical member is any one of the first to thirteenth aspects, wherein the optical member is preferably a lid member for covering a base of a package. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a method for manufacturing an optical member that is less affected by shrinkage and has improved mass productivity. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic plan view of a powder compact. [Figure 2] FIG. 2 is a schematic plan view of a quartz sintered body. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an enlarged portion of the quartz sintered body shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of an optical member. [Figure 5] FIG. 5 is a schematic cross-sectional view of the package. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. In the following description of the content of each component, "%" means "% by mass" and "ppm" means "ppm by mass" unless otherwise specified.

[0024] <Method of manufacturing optical members> The method for producing an optical member of the present invention is characterized in that the optical member is made of a quartz sintered body, and includes a pressing step of pressing a quartz precursor to obtain a green compact, and a firing step of firing the green compact to obtain a quartz sintered body, wherein the quartz precursor has an average particle size of 30 μm or less. In the following description, an optical member made of a quartz sintered body may be simply referred to as a "quartz sintered body" or an "optical member."

[0025] (Powder compaction process) In the powder compacting step, the quartz precursor is pressed to obtain a powder compact. The pressing method is not particularly limited, and methods such as isostatic pressing, hot pressing, and hot isostatic pressing can be used.

[0026] The pressing pressure can be adjusted appropriately within the range of 0.1 MPa to 100 MPa. From the viewpoint of obtaining a particularly dense sintered body, the lower limit of the pressing pressure is preferably 0.1 MPa or more, 1 MPa or more, 5 MPa or more, and particularly 8 MPa or more. If the pressing pressure is less than 0.1 MPa, it becomes difficult to obtain a green compact with sufficient strength. On the other hand, if the pressing pressure exceeds 100 MPa, the pressing device tends to become larger, increasing the manufacturing cost.

[0027] The pressing temperature is preferably 1400°C or less, 1300°C or less, less than 1300°C, 1250°C or less, particularly 1200°C or less, 1000°C or less, 950°C or less, particularly 900°C or less. The lower limit of the pressing temperature is preferably 100°C or more, 250°C or more, 300°C or more, particularly 400°C or more. However, the pressing temperature may be less than 100°C or less than 50°C, or pressing may be performed at room temperature.

[0028] The material of the press die is not particularly limited, and examples of materials that can be used include stainless steel, carbon, silicon nitride, titanium carbide, etc. When producing an optical component having lens portions, it is preferable to use a press die having a shape corresponding to the plurality of lens portions, since multiple lens portions will be formed in the green compact.

[0029] The surface roughness Ra of the pressing die is preferably 1 μm or less, less than 1 μm, and particularly preferably 0.9 μm or less. This improves the surface quality of the green compact after pressing. There is no particular lower limit to the surface roughness Ra of the pressing die, but it may be, for example, 5 nm or more, 10 nm or more, and particularly preferably 50 nm or more.

[0030] The quartz precursor preferably contains quartz powder. For example, the quartz precursor is preferably made of quartz powder. Furthermore, from the viewpoint of ease of handling, the quartz precursor preferably contains granulated quartz powder. For example, the quartz precursor is preferably made of granulated quartz powder. Granulated quartz powder can be obtained, for example, by adding a binder or the like to quartz powder and granulating the resulting mixture. A mixture of quartz powder and granulated quartz powder may also be used as the quartz precursor. In the following description, "granulated quartz powder" may be simply referred to as "granulated material." Furthermore, commercially available quartz raw materials can be used for the quartz precursor and quartz powder. Specifically, the quartz precursor and / or quartz powder preferably consists of at least one selected from natural quartz, fused quartz, and synthetic quartz (e.g., fumed silica, colloidal silica). From the viewpoint of improving the light transmittance of the quartz sintered body in the short wavelength range, the quartz precursor and / or quartz powder preferably consists of synthetic quartz.

[0031] The average particle size of the quartz precursor is preferably 30 μm or less, 20 μm or less, less than 10 μm, 9 μm or less, 5 μm or less, 1000 nm or less, 800 nm or less, 500 nm or less, 300 nm or less, and particularly preferably 200 nm or less. The smaller the average particle size of the quartz precursor, the easier it is to lower the firing temperature. On the other hand, from the viewpoint of ease of handling, the lower limit of the average particle size of the quartz precursor is preferably 5 nm or more, 10 nm or more, 15 nm or more, and particularly preferably 50 nm or more. Furthermore, from the viewpoint of reducing the haze of the quartz sintered body, the lower limit of the average particle size of the quartz precursor is preferably 100 nm or more, and particularly preferably 150 nm or more. In the present invention, the average particle size is the median diameter of the primary particles, D 50 (50% volume cumulative diameter) and is a value measured using a laser diffraction particle size distribution analyzer.

[0032] For example, the average particle size of the quartz powder is preferably 30 μm or less, 20 μm or less, less than 10 μm, 9 μm or less, 5 μm or less, 1000 nm or less, 800 nm or less, 500 nm or less, 300 nm or less, 200 nm or less, and particularly preferably 100 nm or less. From the viewpoint of ease of handling, the lower limit of the average particle size of the quartz powder is preferably 5 nm or more, 10 nm or more, and particularly preferably 15 nm or more.

[0033] For example, the average particle size of the granulated product is preferably 30 μm or less, 20 μm or less, less than 10 μm, 9 μm or less, 5 μm or less, 1000 nm or less, 800 nm or less, 500 nm or less, 200 nm or less, and particularly preferably 100 nm or less. From the viewpoint of ease of handling, the lower limit of the average particle size of the granulated product is preferably 5 nm or more, 10 nm or more, 15 nm or more, and particularly preferably 50 nm or more.

[0034] The specific surface area of ​​the quartz precursor is 100m 2 / g or less, 90m 2 / g or less, 50m 2 / g or less, especially 30m 2 / g or less. If the specific surface area of ​​the quartz precursor is too large, the shrinkage rate tends to be large. There is no particular lower limit to the specific surface area, but for example, 2 The specific surface area is a value calculated from the results of pore distribution measurement using a nitrogen adsorption method.

[0035] For example, the specific surface area of ​​quartz powder is 100m 2 / g or less, 90m 2 / g or less, 50m 2 / g or less, especially 30m 2 / g or less. If the specific surface area of ​​the quartz powder is too large, the shrinkage rate tends to increase. There is no particular lower limit to the specific surface area, but for example, 2 / g or more.

[0036] The quartz powder is preferably approximately spherical. This makes it easier to obtain a dense quartz sintered body. The quartz powder is particularly preferably spherical. However, the quartz powder is not limited to approximately spherical or spherical shapes.

[0037] In the compacting step, a binder may be added in an amount of 0% to 10% by mass, particularly 0% to 5% by mass, relative to 100% by mass of the quartz precursor. However, from the viewpoint of reducing the amount of shrinkage when the compact is fired, it is preferable not to add a binder in the compacting step. The type of binder that can be used in the compacting step can be the same as the type of binder described in the granulation step, which will be described later. Furthermore, the same binder may be used in the granulation step and the compacting step, or different binders may be used.

[0038] When a granulated material is used as the quartz precursor, it is preferable to include a step (granulation step) of adding a binder to the quartz powder and granulating the mixture to obtain a granulated material before the compaction step. For example, a granulated material can be obtained by preparing a mixture containing quartz powder, water, and a binder, and granulating the mixture. Alternatively, an organic solvent (alcohol, ethanol, butanol, etc.) may be added to reduce the slurry viscosity. Known granulation methods can be used, including fluidized bed granulation, stirring granulation, tumbling granulation, spray drying, freeze granulation, extrusion granulation, and coating granulation. For example, it is preferable to use any method selected from fluidized bed granulation, spray drying, and freeze granulation, with freeze granulation being particularly preferable. The freeze granulation method makes it easier to obtain a dense green compact and quartz sintered body because large bubbles are less likely to form in the center of the granulated material when it is heated and dried.

[0039] (Specific surface area of ​​quartz powder / average particle diameter of granulated material D 50造粒物 ) is 10 x 10 6 m / g or less, 5×10 6 m / g or less, especially 1×10 6 m / g or less. When this ratio satisfies the above value, aggregation of the quartz powder in the granulation process is easily suppressed. Also, the shrinkage rate of the quartz sintered body is easily reduced. The lower limit is not particularly limited, but is, for example, 0.1 × 10 6 m / g or more. 50造粒物 " is the specific surface area (m 2 / g) was calculated as the average particle diameter D 50造粒物 This means the value divided by (m).

[0040] In the granulation step, the content of quartz powder is preferably 20% by mass or more, particularly 30% by mass or more. The upper limit of the content of quartz powder is preferably 80% by mass or less, particularly 70% by mass or less. If the content of quartz powder is too high or too low, granulation becomes difficult.

[0041] In the granulation step, the water content is preferably 20% by mass or more, particularly 30% by mass or more. The upper limit of the water content is preferably 80% by mass or less, particularly 70% by mass or less. If the water content is too high or too low, granulation becomes difficult.

[0042] The amount of binder added in the granulation step is preferably 0.1% by mass or more, 1% by mass or more, and particularly 2% by mass or more, when the total amount of quartz powder and water is taken as 100% by mass. The upper limit of the amount of binder added is preferably 10% by mass or less, 8% by mass or less, and particularly 5% by mass or less. If the amount of binder added is too small, granulation tends to be insufficient. If the amount of binder added is too large, dimensional change tends to be large when the quartz precursor is fired.

[0043] Commercially available resin binders can be used as binders, such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyimide (PI), polyamide, polyamide-imide, acrylic resin, styrene butadiene rubber (SBR), ethylene-vinyl acetate copolymer (EVA), polypropylene carbonate (PPC), styrene-ethylene-butylene-styrene copolymer (SEBS), carboxymethyl cellulose (CMC), xanthan gum, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), ethylene vinyl alcohol, polyethylene (PE), polypropylene (PP), polyacrylic acid, lithium polyacrylate, sodium polyacrylate, potassium polyacrylate, ammonium polyacrylate, methyl polyacrylate, ethyl polyacrylate, and polyacrylic acid. Materials that can be used as binders include acid amines, polyacrylates, epoxy resins, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), nylon, vinyl chloride, silicone rubber, nitrile rubber, cyanoacrylate, urea resin, melamine resin, phenolic resin, latex, polyurethane, silylated urethane, nitrocellulose, dextrin, polyvinylpyrrolidone, vinyl acetate, polystyrene, chloropropylene, resorcinol resin, polyaromatic, modified silicone, methacrylic resin, polybutene, butyl rubber, 2-propenoic acid, cyanoacrylic acid, methyl methacrylate, glycidyl methacrylate, acrylic oligomer, 2-hydroxyethyl acrylate, polyacetal, and alginic acid. For example, hydrophilic binders are preferred. Examples of hydrophilic binders include acrylic binders and epoxy binders.

[0044] In the granulation step, other additives such as dispersants, plasticizers, and organic solvents may be added. The amount of the other additives added is preferably 5% by mass or less, 3% by mass or less, and particularly 1% by mass or less, when the total amount of the quartz powder and water is taken as 100% by mass. The lower limit of the amount of the other additives added may be 0% by mass or more, 0.01% by mass or more, and particularly 0.1% by mass or more.

[0045] A dispersant can be added to suppress aggregation. The type of dispersant is not particularly limited, but it is preferable to use, for example, an ionic or nonionic dispersant. As the ionic dispersant, it is preferable to use, for example, a polycarboxylic acid dispersant such as a carboxylic acid or a dicarboxylic acid, or an amine dispersant. For example, it is preferable to use a dispersant containing polyethyleneimine. As the nonionic dispersant, it is preferable to use, for example, a polyester condensation type or a polyhydric alcohol ether type dispersant.

[0046] As the plasticizer, butyl benzyl phthalate, dioctyl phthalate, diisooctyl phthalate, dicapryl phthalate, dibutyl phthalate, etc. can be used alone or in combination.

[0047] As the organic solvent, for example, terpineol (Ter), diethylene glycol monobutyl ether (BC), diethylene glycol monobutyl ether acetate (BCA), 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, dihydroterpineol, etc. can be used alone or in combination.

[0048] FIG. 1 is a schematic plan view of a powder compact. In FIG. 1, the powder compact 20 has a plurality of lens portions 2. By firing the powder compact 20, a quartz sintered body having a plurality of lens portions 2 can be obtained. Furthermore, as will be described later, a desired optical member can be obtained by singulating the quartz sintered body. Note that although the powder compact 20 in FIG. 1 is a rectangular plate having a plurality of lens portions 2, the shape of the powder compact is not limited to a rectangular plate. For example, the powder compact preferably has a shape that will yield a quartz sintered body that can be singulated into a desired optical member. For example, it may be in the shape of a plate, a disk, or a rod. Furthermore, the powder compact 20 may have a shape corresponding to the optical member (i.e., a shape that does not require a singulation process).

[0049] The length of the powder compact is preferably 5 mm or more, 10 mm or more, 15 mm or more, and particularly preferably 20 mm or more. There is no particular upper limit to the length of the powder compact, but from the viewpoint of preventing the press device from becoming too large, it is preferably 100 mm or less, 80 mm or less, and particularly preferably 60 mm or less. Note that the "length of the powder compact" is preferably the length of the longest diagonal line in the case of a plate-shaped powder compact. Furthermore, it is preferably the length of the diameter in the case of a disk-shaped powder compact. Furthermore, it is preferably the length of the longest side in the case of a rod-shaped powder compact.

[0050] The thickness of the powder compact is preferably 0.01 mm to 10 mm, 0.05 mm to 5 mm, and particularly preferably 0.1 mm to 2.5 mm. If the thickness of the powder compact is too small, the mechanical strength of the resulting quartz sintered body is likely to decrease. On the other hand, if the thickness of the powder compact is too large, sintering is likely to be insufficient. In the case of a powder compact having a lens portion, the thickness of the powder compact can be the linear distance connecting the apex of the lens portion and the other main surface of the powder compact.

[0051] (Debinding process) If the powder compact contains a binder, it is preferable to perform a binder removal treatment in which the powder compact is heated to remove the binder before the firing step. In the binder removal treatment, the treatment temperature is preferably 300°C or higher, 350°C or higher, 400°C or higher, and particularly 450°C or higher. If the treatment temperature is too low, the binder may not be sufficiently removed. There is no particular upper limit to the treatment temperature, but it may be, for example, 700°C or lower, particularly 650°C or lower. There is no particular limit to the treatment time, but it may be, for example, 0.5 to 3 hours, particularly 0.5 to 2 hours.

[0052] (Firing process) In the firing process, the green compact is fired to obtain a quartz sintered body. In particular, when the singulation process described below is included, the green compact is fired to obtain a sintered base material consisting of a quartz sintered body. The firing temperature is preferably less than 1400°C, less than 1350°C, or less than 1300°C, and particularly 1250°C or less. The lower limit of the firing temperature is preferably 900°C or higher, particularly 1000°C or higher. If the firing temperature is too low, sintering will be insufficient, resulting in low light transmittance of the quartz sintered body (optical component). If the firing temperature is too high, heterogeneous crystals will precipitate, causing cloudiness, and the energy consumption during production will increase, increasing production costs.

[0053] The firing time can be adjusted appropriately so that the powder compact is sufficiently sintered. For example, the firing time is preferably 0.1 to 10 hours, 1 to 9 hours, and particularly preferably 3 to 8 hours.

[0054] The firing atmosphere is preferably an inert atmosphere, a reducing atmosphere, or a vacuum atmosphere. This promotes degassing during firing, making it easier to obtain a dense sintered body. A vacuum atmosphere is particularly preferred because it is easy to reduce fine voids at the interface of the sintered body. In addition, an inert gas may be introduced when the vacuum atmosphere is returned to atmospheric pressure to shrink the voids. Note that firing may be performed in an air atmosphere to prevent the manufacturing equipment from becoming too large.

[0055] To reduce OH groups in the glass and further improve light transmittance in the short wavelength region, heat treatment may be performed in a nitrogen-hydrogen atmosphere. The heat treatment temperature is preferably 500°C to 1000°C, and the holding time is preferably 10 hours or less.

[0056] According to the method for producing an optical member of the present invention, the amount of shrinkage when the green compact is fired is small, making it easy to obtain a quartz sintered body with little cracking or deformation. More specifically, the shrinkage rate of the quartz sintered body, as expressed by the following formula, is preferably 50% or less, 30% or less, 25% or less, and particularly preferably 20% or less.

[0057] Shrinkage rate (%) = (1-b / a) x 100 Here, a means the length of the green compact, and b means the length of the quartz sintered body b. The length of the quartz sintered body can be determined in the same way as the length of the green compact described above. For example, in the case of a disk-shaped quartz sintered body, the diameter can be used as the length.

[0058] The quartz sintered body has a shape corresponding to the shape of the compact, and is preferably a plate-shaped, disk-shaped, or rod-shaped optical element or sintered base material. The length of the quartz sintered body is preferably 10 mm or more, 15 mm or more, and particularly 20 mm or more. The upper limit of the length of the quartz sintered body is not particularly limited, but is preferably, for example, 100 mm or less, 80 mm or less, and particularly 60 mm or less. The thickness of the quartz sintered body is preferably 0.01 mm or more, 0.1 mm or more, 0.5 mm or more, and particularly 1 mm or more, and is preferably 10 mm or less, 8 mm or less, 5 mm or less, and particularly 2.5 mm or less. In the case of a quartz sintered body having a lens portion, the thickness of the quartz sintered body can be the linear distance connecting the apex of the lens portion and the other main surface of the quartz sintered body.

[0059] FIG. 2 is a schematic plan view of a quartz sintered body. The quartz sintered body 21 shown in FIG. 2 can be obtained by firing the green compact shown in FIG. 1 and has a plurality of lens portions 2. In other words, the quartz sintered body 21 is a sintered base material having a shape in which optical members are continuously formed before being singulated. In this embodiment, the desired optical members can be obtained by singulating the quartz sintered body 21. Note that the quartz sintered body 21 shown in FIG. 2 is a rectangular plate-shaped sintered base material having a plurality of lens portions 2, but the shape is not limited to a rectangular plate. The shape of the sintered base material may be any shape that can be used to obtain the desired optical members by singulating, and may be, for example, a plate, a disk, or a rod.

[0060] (Singulation process) The method for producing an optical member of the present invention preferably further comprises a singulation step of singulating the obtained quartz sintered body. This allows optical members to be efficiently produced from a sintered base material made of a quartz sintered body. Furthermore, when the quartz sintered body is a sintered base material having a plurality of lens portions, optical members made of a quartz sintered body having lens portions can be obtained by singulating the quartz sintered body. Examples of singulation methods that can be used include cutting using a dicer (blade dicing), laser cutting, and water beam cutting. Singulation by blade dicing is particularly preferred.

[0061] Fig. 3 is a schematic cross-sectional view showing an enlargement of a portion of the quartz sintered body shown in Fig. 2. By cutting the quartz sintered body 21 along the cutting line CL, a plurality of optical members can be efficiently manufactured. In addition, in this embodiment, since the quartz sintered body 21 is a sintered base material having a plurality of lens portions 2, optical members made of the quartz sintered body having lens portions can be obtained by dividing it into individual pieces.

[0062] (Surface finishing process) The method for producing an optical member of the present invention preferably further comprises a surface finishing step. This improves the surface quality of the optical member and makes it easier to suppress the generation of scattered light. Surface finishing can be performed, for example, by mirror polishing, lapping, or fire polishing. In particular, from the viewpoint of reducing the haze of the quartz sintered body, mirror polishing or fire polishing is preferable. Fire polishing can be performed using a burner or an electric furnace.

[0063] <Quartz sintered bodies, optical components> The lower limit of the SiO2 content of the quartz sintered body is preferably 95% or more, 98% or more, and particularly 99% or more. This configuration can increase light transmittance in the short wavelength range. The upper limit of the SiO2 content is not particularly limited, but it may be 100% or less, less than 100%, and particularly 99.99% or less. The components of the quartz sintered body can be evaluated using energy dispersive X-ray spectroscopy (EDX), electron probe microanalyzer (EPMA), X-ray fluorescence spectroscopy (XRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), etc. EDX can also be evaluated using TEM-EDX or SEM-EDX devices attached to transmission electron microscopes (TEM) or scanning electron microscopes (SEM).

[0064] To improve light transmittance in the short wavelength region, the quartz sintered body preferably contains Na2O, K2O, TiO2, Fe2O3, MnO2, and Al2O3 in a total amount of 500 ppm or less, 400 ppm or less, 300 ppm or less, and particularly 200 ppm or less, in terms of mass ppm of oxide. Furthermore, to improve light transmittance particularly in the short wavelength region, the total amount of Na2O, K2O, TiO2, Fe2O3, MnO2, and Al2O3 is preferably 100 ppm or less, 50 ppm or less, and particularly 30 ppm or less. To prevent increases in raw material costs, the lower limit of the total amount of Na2O, K2O, TiO2, Fe2O3, MnO2, and Al2O3 may be, for example, 0.01 ppm or more, 0.1 ppm or more, and particularly 1 ppm or more. The preferred contents of these trace components are described below.

[0065] The quartz sintered body preferably has a Na2O+K2O content (total amount of Na2O and K2O) of 150 ppm or less, 100 ppm or less, 50 ppm or less, less than 10 ppm, 5 ppm or less, and particularly 1 ppm or less. As the Na2O+K2O content increases, devitrification occurs, making the quartz sintered body more likely to have a reduced light transmittance. Furthermore, localized degradation due to ultraviolet light is more likely to occur. The lower limit of the Na2O+K2O content is not particularly limited, but may be, for example, 0.01 ppm or more. The contents of the Na2O and K2O components are preferably 150 ppm or less, 100 ppm or less, 50 ppm or less, less than 10 ppm, 5 ppm or less, and particularly 1 ppm or less, and may be 1 ppb or more.

[0066] The quartz sintered body preferably has a TiO2 content of less than 10 ppm, 5 ppm or less, 1 ppm or less, and particularly 0.5 ppm or less. As the TiO2 content increases, the light transmittance of the quartz sintered body tends to decrease. There is no particular lower limit for the TiO2 content, but it may be, for example, 1 ppb or more.

[0067] The quartz sintered body preferably has an Fe2O3 content of 100 ppm or less, 50 ppm or less, less than 10 ppm, 5 ppm or less, and particularly 1 ppm or less. As the Fe2O3 content increases, the light transmittance of the quartz sintered body tends to decrease. There is no particular lower limit for the Fe2O3 content, but it may be, for example, 1 ppb or more.

[0068] The quartz sintered body preferably has an MnO2 content of less than 10 ppm, 5 ppm or less, 1 ppm or less, 0.1 ppm or less, and particularly 0.05 ppm or less. As the MnO2 content increases, the light transmittance of the quartz sintered body tends to decrease. There is no particular lower limit for the MnO2 content, but it may be, for example, 1 ppb or more.

[0069] The quartz sintered body preferably has an Al2O3 content of 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, less than 10 ppm, and particularly preferably 5 ppm or less. As the Al2O3 content increases, the light transmittance of the quartz sintered body tends to decrease. There is no particular lower limit for the Al2O3 content, but it may be, for example, 1 ppb or more.

[0070] 4 is a schematic cross-sectional view of an optical member. In this embodiment, the optical member 10 has a base portion 1 and a lens portion 2. In other words, the optical member 10 is made of a quartz sintered body and has a lens portion 2. However, the manufacturing method of the present invention can also be used to suitably manufacture optical members that do not have a lens portion 2.

[0071] The optical member preferably has a light transmittance of 40% or more, 60% or more, and particularly 80% or more at a wavelength of 250 nm when the member is 1 mm thick. The upper limit of the light transmittance at a wavelength of 250 nm is not particularly limited, but it may be 100% or less, particularly 95% or less. The above light transmittance is a value including light reflection (total light transmittance).

[0072] The optical member preferably has a total light transmittance of 40% or more, 60% or more, particularly 80% or more at a wavelength of 280 nm when the optical member has a thickness of 1 mm. The upper limit of the total light transmittance at a wavelength of 280 nm is not particularly limited, but may be 100% or less, particularly 95% or less.

[0073] The optical member preferably has a diffuse light transmittance at a wavelength of 280 nm at a thickness of 1 mm of less than 20%, 10% or less, and particularly 5% or less. The lower limit of the diffuse light transmittance at a wavelength of 280 nm is not particularly limited, but may be 0% or more, or 0.5% or more.

[0074] The haze of the optical member is preferably 0 to 20%, 15% or less, 10% or less, and particularly preferably 5% or less. This can reduce diffuse reflection on the surface and inside of the optical member, thereby reducing light loss. The haze can be calculated using the following formula. Alternatively, it can be measured using a commercially available haze meter.

[0075] Haze (%) = (Diffuse light transmittance / Total light transmittance) x 100

[0076] The optical member can be suitably used as an optical member usable in a short wavelength region (for example, an ultraviolet region or a deep ultraviolet region). For example, the optical member can be suitably used as an optical member usable in a wavelength region of 100 nm to 350 nm, a wavelength region of 100 nm to 280 nm, and particularly a wavelength region of 100 nm to 250 nm. The optical member can also be suitably used as a lid member or a lid member with a lens portion for covering a package base (LED package base) for the ultraviolet region or the deep ultraviolet region. However, the optical member is not limited to use in the short wavelength region, and may also be used in the visible wavelength region or the near-infrared wavelength region.

[0077] 5 is a schematic cross-sectional view of a package. The package 100 includes a base 4, a light emitting element 3 supported by the base 4, an optical member 10 covering the base 4 and the light emitting element 3, and a sealing portion 5 hermetically joining the base 4 and the optical member 10. That is, in this embodiment, the optical member 10 is a lid member that covers the base 4 and the light emitting element 3.

[0078] The light emitting element is fixed on one of the main surfaces of the base. In this embodiment, a package using an ultraviolet irradiating LED as the light emitting element is exemplified, but an infrared LED or a visible light LED may also be used as the light emitting element.

[0079] Examples of materials for the substrate include ceramics such as aluminum nitride, aluminum oxide, silicon carbide, and silicon nitride, glass ceramics obtained by mixing and sintering these ceramics with glass powder, and alloys such as Fe-Ni-Co alloys, Cu-W alloys, Au-Sn alloys, and Kovar (registered trademark).

[0080] The sealing portion is formed by integrally bonding the base and the optical member. The material of the sealing portion is not particularly limited, and any desired sealing material can be used. [Example]

[0081] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0082] [Table 1]

[0083] [Table 2]

[0084] [Table 3]

[0085] (Examples 1 to 6) First, quartz powder, water, binder (acrylic binder: AP-15 manufactured by HighChem), and dispersant (polyethyleneimine: P-1000 manufactured by Nippon Shokubai Co., Ltd.) were mixed to the contents shown in Table 1 and granulated. As the quartz powder, fumed silica (manufactured by Nippon Aerosil Co., Ltd.) was used in Examples 1 and 2, spherical fused quartz powder (manufactured by Denka Co., Ltd.) was used in Example 3, and spherical synthetic quartz powder (Silfil manufactured by Tokuyama Corporation) was used in Examples 4-6. The amounts of binder and dispersant added (mass %) are based on the quartz powder and water mixture being 100 mass %. Next, the granulated material was placed in a 20 mm diameter mold and pressed at a pressure of 10 MPa to obtain a green compact measuring 20 mm diameter and 5 mm thick. The obtained green compact was subjected to a debindering process under the conditions shown in Table 2. The green compact after the debindering process was heated under the conditions shown in Table 2 to obtain a plate-shaped quartz sintered body. The shape, minor components, and shrinkage of the obtained quartz sintered body are shown in Table 3. The obtained quartz sintered body was cut into individual pieces of 10 mm square and 1 mm thick using a dicer to obtain individual quartz sintered bodies. The optical transmittance λ250 at a wavelength of 250 nm was measured using the individual quartz sintered body.

[0086] The light transmittance at a wavelength of 250 nm was measured using a spectrophotometer (V-670 manufactured by JASCO Corporation). Individual pieces of quartz sintered body (10 mm square, 1 mm thick) were used for the measurement. Note that the "light transmittance at a wavelength of 250 nm" refers to the light transmittance including reflection (total light transmittance).

[0087] The contents of trace elements were measured using LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry). In Table 3, the total content of Na2O, K2O, TiO2, Fe2O3, MnO2, and Al2O3 is listed as the "total amount of trace elements."

[0088] The shrinkage rate was calculated using the following formula by measuring the diameter a of the green compact before sintering and the diameter b of the green compact (quartz sintered body) after sintering with a vernier caliper.

[0089] Shrinkage rate (%) = (1-b / a) x 100

[0090] An additional sample having the same structure as Example 5 was prepared, and the surface of the quartz sintered body was subjected to a surface finishing process to obtain a sample with a thickness of 1 mm. Furthermore, using a spectrophotometer (JASCO V-670), the total light transmittance and diffuse light transmittance for light with a wavelength of 280 nm were measured. Furthermore, the haze was calculated using the following formula.

[0091] Haze (%) = (Diffuse light transmittance / Total light transmittance) x 100

[0092] Surface finishing treatments included mirror polishing, lapping using alumina abrasive grains with a roughness of #1000, and fire polishing using a burner or electric furnace. Fire polishing using a burner was performed by heating the surface of the quartz sintered body for approximately 30 seconds using an oxyhydrogen burner. Fire polishing using an electric furnace was performed by placing the quartz sintered body in a high-multi electric furnace (manufactured by Fuji Dempa Kogyo) and heat-treating it at 1700°C for 3 minutes. The results are shown in Table 4.

[0093] [Table 4]

[0094] (Comparative Example) First, quartz powder (fumed silica: manufactured by Nippon Aerosil Co., Ltd.), water, binder (acrylic binder: manufactured by HighChem, AP-15), and dispersant (polyethyleneimine: manufactured by Nippon Shokubai, P-1000) were mixed in the amounts shown in Table 1 to obtain a synthetic quartz slurry. The resulting slurry was poured into a 50 mm diameter x 10 mm thick mold and dried at 20°C for 48 hours to obtain a dried body. After drying, the dried body was subjected to a debindering process under the conditions shown in Table 2. The debindered dried body was then heated under the conditions shown in Table 2 to obtain a plate-shaped quartz sintered body.

[0095] Table 1 shows the light transmittance and shrinkage at a wavelength of 250 nm for the Examples and Comparative Examples. As shown in Table 1, the λ250 of the Examples was high, at 40% or more. In particular, in Examples 1 and 2, where the total amount of trace components was 100 ppm or less, the λ250 was high, at 80% or more. The shrinkage of the Examples was also 30% or less. On the other hand, the shrinkage of the Comparative Example was high, at 60%, and the sample cracked.

[0096] As shown in Table 4, the total light transmittance at a wavelength of 280 nm of the obtained quartz sintered bodies in Examples 5-2, 5-4, and 5-5 was 89%, which was higher than that of the unpolished Example 5-1. In addition, the haze was low, at 5% or less, in Examples 5-2, 5-4, and 5-5. [Industrial Applicability]

[0097] The method for producing an optical member of the present invention can be suitably used for producing an optical member usable in the short wavelength region, particularly in the ultraviolet region or deep ultraviolet region. The obtained optical member can be suitably used as a lid member or a lid member with a lens portion for covering the base of various packages usable in the ultraviolet region or deep ultraviolet region. [Explanation of symbols]

[0098] 1 base 2 Lens section 3 Light-emitting element 4 Base 5 Sealing part 10 Optical components 20 Powder Compacts 21 Quartz sintered body 100 packages

Claims

1. A method for manufacturing an optical member, comprising: the optical member is made of a quartz sintered body, a compacting step of pressing the quartz precursor to obtain a green compact; a firing step of firing the powder compact to obtain a quartz sintered body, The method for producing an optical member, wherein the average particle size of the quartz precursor is 30 μm or less.

2. A method for manufacturing an optical member, comprising: the optical member is made of a quartz sintered body and has a lens portion; a compacting step of pressing the quartz precursor to obtain a green compact having a plurality of lens portions; a firing step of firing the powder compact to obtain a quartz sintered body, The method for producing an optical member, wherein the average particle size of the quartz precursor is 30 μm or less.

3. The method for manufacturing an optical member according to claim 1 or 2, further comprising a step of singulating the quartz sintered body into individual pieces.

4. The method for producing an optical member according to claim 1 or 2, wherein the quartz precursor contains quartz powder.

5. The method for manufacturing an optical member according to claim 4 , wherein the quartz powder is substantially spherical.

6. The method for producing an optical member according to claim 4, wherein the average particle size of the quartz powder is 1000 nm or less.

7. The method for producing an optical member according to claim 1 or 2, wherein the quartz precursor is made of synthetic quartz.

8. The quartz sintered body is made of Na ２ O+K ２ The content of O is 150 mass ppm or less, and TiO ２ The content of is less than 10 mass ppm, Fe ２ O ３ The method for producing an optical member according to claim 1 or 2, wherein the content of

9. The method for producing an optical member according to claim 1 or 2, wherein in the powder compacting step, the pressing die has a surface roughness Ra of 1 μm or less.

10. The method for producing an optical member according to claim 1 or 2, wherein the firing temperature in the firing step is lower than 1400°C.

11. The method for manufacturing an optical member according to claim 1 or 2, wherein the quartz sintered body has a shrinkage rate of 50% or less relative to the compact.

12. The method for producing an optical member according to claim 1 or 2, wherein the length of the quartz sintered body is 10 mm or more.

13. The method for producing an optical member according to claim 1 or 2, wherein the optical member has a light transmittance of 40% or more at a wavelength of 250 nm when the optical member has a thickness of 1 mm.

14. The method for manufacturing an optical member according to claim 1 or 2, wherein the optical member is a cover member for covering a base of a package.

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