WO2012008358A1

WO2012008358A1 - Synthetic quartz glass for ultraviolet ray cut filter, and process for production thereof

Info

Publication number: WO2012008358A1
Application number: PCT/JP2011/065604
Authority: WO
Inventors: 朝敬小川; 小池　章夫
Original assignee: 旭硝子株式会社
Priority date: 2010-07-14
Filing date: 2011-07-07
Publication date: 2012-01-19
Also published as: JP2013189321A

Abstract

The present invention relates to a synthetic quartz glass for an ultraviolet ray cut filter, in which not less than 0.015 mass% and less than 0.4 mass% of Ce is doped, and which is characterized in that 90% or more of the doped Ce is present in the form of Ce³⁺.

Description

Synthetic quartz glass for ultraviolet cut filter and method for producing the same

The present invention relates to a synthetic quartz glass for an ultraviolet cut filter that maintains a low transmittance of ultraviolet light, while maintaining a high transmittance of visible light and near infrared light, and a method for manufacturing the same. The present invention relates to a synthetic quartz glass for an ultraviolet cut filter and a method for producing the same.

In recent years, technology using high-power lasers has attracted attention in various fields such as lithography technology for semiconductor manufacturing, laser processing technology, laser fusion technology, medical technology, and verification of pure science.

Furthermore, miniaturization of lithography technology and laser processing have been promoted by shortening the wavelength of high-power lasers and using light in the ultraviolet region, and the influence of heat has been suppressed by using ultraviolet light. Processing is also possible, and plastics can be processed in addition to metal and glass. As such a high-power ultraviolet laser light source, an excimer laser that is a gas laser such as ArF (wavelength 193 nm) or KrF (wavelength 248 nm), or a third harmonic (350 nm) such as a solid-state laser YAG laser or YLF laser. Near) and the fourth harmonic (around 265 nm).

Since the fundamental oscillation wavelength of such a solid-state laser is near-infrared near 1050 nm, it is a high-order harmonic ultraviolet laser using a wavelength conversion element (crystal). However, when wavelength conversion is performed using this wavelength conversion element, part of the converted high-energy UV laser light is scattered or reflected by the lenses and mirrors that make up the subsequent optical system, and laser optics before wavelength conversion. Returned to system parts and sometimes caused damage.

Damaged parts must be replaced each time, so operation must be stopped and production of the product must be stopped, and the cost of replacing parts was high, so the optical system for high-power lasers There has been a demand for a technique for reducing damage to parts caused by ultraviolet rays.

Although not conventionally used for high-power lasers, UV-cut filter glass is made of glass that has been laminated with a multilayer film to prevent UV transmission, and quartz glass doped with UV-absorbing doping material that transmits UV light. A technique such as quartz glass (see Patent Document 1) that is not allowed to occur is known.

Japanese Unexamined Patent Publication No. 7-315863

However, when a multilayered glass film is used for a high-power laser, for example, in the case of a reflective multilayer film, it may cause multiple scattering, resulting in stray light and irradiating optical components with ultraviolet rays. In the case of the mold multilayer film, there is a problem that the film is damaged.

In addition, in the conventional quartz glass doped with the ultraviolet absorbing doping material of Patent Document 1, the concentration of the ultraviolet absorbing doping material has to be increased if enough ultraviolet rays are to be cut. However, if the concentration of the UV-absorbing doping material is lowered to maintain the visible light transmittance, the UV light cannot be sufficiently cut.

Therefore, the present invention has been made paying attention to the above problems, and can sufficiently reduce the transmittance of unnecessary ultraviolet rays, and can maintain the transmittance of visible light and near infrared light at a high level. An object of the present invention is to provide a synthetic quartz glass for an ultraviolet cut filter suitable for an output laser.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by including a specific element component having an adjusted electronic valence in synthetic quartz glass, and have completed the present invention.

That is, the synthetic quartz glass of the present invention is a synthetic quartz glass doped with 0.015 mass or more and less than 0.4 mass% of Ce, and 90% or more of the doped Ce is Ce ³⁺ . Exists in a state.

In the present invention, when the thickness of the quartz glass for ultraviolet cut filter is adjusted so that the internal transmittance of light with a wavelength of 351 nm is 5%, the internal transmittance of light with a wavelength of 375 nm is 50% or more and the wavelength is 400 nm. It is preferable that the internal transmittance of light is 90% or more and the internal transmittance of light in a wavelength region of 500 to 1100 nm is 95% or more.

In the present invention, the density of internal defects of the synthetic quartz glass is preferably 5 × 10 ⁻⁴ pieces / cm ³ or less.

In the present invention, it is preferable that the thickness of the synthetic quartz glass for an ultraviolet cut filter is 5 mm to 45 mm when the internal transmittance of light having a wavelength of 351 nm is adjusted to 5%.

In the present invention, the synthetic quartz glass is preferably used for transmission of a high-power laser.

Further, the method for producing synthetic quartz glass of the present invention is a porous glass in which SiO ₂ glass fine particles obtained by flame hydrolysis of a raw material Si compound are deposited and grown on a substrate to form a porous SiO ₂ glass body. Body formation process,
After the Ce compound-containing solution is contained in the obtained porous SiO ₂ glass body, a Ce doping step of doping Ce by removing the solvent,
And a vitrification step of heating the SiO ₂ porous glass doped with Ce to a vitrification temperature under a reduced pressure of less than 100 Pa or in an inert gas atmosphere to obtain a transparent glass body.

Furthermore, another synthetic quartz glass manufacturing method of the present invention is a porous porous material in which SiO ₂ glass fine particles obtained by flame hydrolysis of raw material Si compound and Ce compound are deposited and grown on a substrate, and Ce is doped. A Ce-doped porous glass body forming step for forming a SiO ₂ glass body;
And a vitrification step of heating the porous SiO ₂ glass body doped with Ce to a vitrification temperature under a reduced pressure of less than 100 Pa or in an inert gas atmosphere to obtain a transparent glass body.

According to the synthetic quartz glass and the method for producing the same of the present invention, it is possible to provide a synthetic quartz glass having an improved ultraviolet absorption rate and a high visible light / near infrared light transmittance. By incorporating this synthetic quartz glass into an optical system for a high-power laser, it is possible to suppress damage due to ultraviolet rays of the optical system parts, and to reduce labor and cost for parts replacement.

Hereinafter, the present invention will be described in detail.

The synthetic quartz glass for an ultraviolet cut filter of the present invention is a synthetic quartz glass doped with 0.015% by mass or more and less than 0.4% by mass of Ce as described above. Of the doped Ce, 90% % Or more is present in the Ce ³⁺ state.

Here, 90% or more of the doped Ce is present in the state of Ce ³⁺ so that the ultraviolet light having a wavelength of 351 nm is effectively cut, and light having a wavelength of 375 nm, a wavelength of 400 nm, etc. is sufficiently transmitted, and a high output In an apparatus using a laser, a synthetic quartz glass having preferable characteristics for an ultraviolet cut filter is obtained.
The doping amount of Ce is preferably 0.015 to 0.3% by mass. More preferably, 95% or more of the doped Ce is present in a Ce ³⁺ state. In this specification, “0.015 to 0.3 mass%” means “0.015 mass% or more and 0.3 mass% or less”, and the same applies to others.

Specifically, when the thickness of the quartz glass for an ultraviolet cut filter is adjusted so that the internal transmittance of light with a wavelength of 351 nm is 5%, the internal transmittance of light with a wavelength of 375 nm is 50% or more and the wavelength of 400 nm is A synthetic quartz glass having an internal light transmittance of 90% or more and an internal light transmittance of 95% or more in a wavelength region of 500 to 1100 nm is preferable. More preferably, synthetic quartz having an internal transmittance of 55% or more for light having a wavelength of 375 nm, an internal transmittance of 90% or more for light having a wavelength of 400 nm, and an internal transmittance of 98% or more for light having a wavelength of 500 to 1100 nm. It is glass. The ultraviolet cut filter having such characteristics can effectively suppress damage to the optical system parts from the ultraviolet rays in an apparatus composed of a high-power laser, and can sufficiently transmit necessary light.
The thickness of the quartz glass for ultraviolet cut filter is preferably 5 mm to 45 mm when the thickness is adjusted so that the internal transmittance of light having a wavelength of 351 nm is 5%. 5 to 20 mm is more preferable, and 5 to 15 mm is more preferable.

In high-power laser devices, it is assumed that large filter glasses, specifically those with external dimensions of several hundreds of millimeters, are used, so if the glass plate thickness is thin, warping of the plate and insufficient strength may occur. There is sex. On the other hand, if the plate thickness is too thick, the weight of the filter glass increases, handling becomes difficult, and the amount of glass used increases, which is not preferable in terms of cost. Therefore, the thickness of the filter glass is preferably 5 mm to 45 mm.

In addition, in the glass for a conventional ultraviolet cut filter, Ce is blended as a component for imparting an ultraviolet cut function. However, in the conventional glass, a state of Ce ⁴⁺ (for example, CeO ₂ ) is mainly contained in the glass. Exist stably. In this case, when used in the above-described high-power laser application, it cannot be said that the ability to cut ultraviolet rays having a wavelength of 351 nm is sufficient, and if the concentration of Ce is increased in order to cut this, the wavelength of 375 nm or 400 nm to be transmitted is desired. This hinders the transmission of light and is not suitable for this application. Moreover, in the Ce ⁴⁺ state (for example, CeO ₂ ), it is likely to precipitate in the SiO ₂ glass, and even in a low concentration compared to the Ce ³⁺ state, it is precipitated as CeO ₂ , and the glass becomes cloudy and cannot be used as a filter glass. There is sex.

The synthetic quartz glass of the present invention is a high-purity quartz glass whose main component is SiO _2. Typically, the concentration of alkali metals (Li, Na, K, etc.) contained is 20 ppb or less in total. The total amount of earth metal (Ca, Mg, etc.) is 10 ppb or less, and the concentration of transition metals (Cr, Fe, Ni, Mo, W, Cu, Ti, etc.) is 10 ppb or less. If these impurities are less than the above-mentioned concentrations, it is possible to suppress a decrease in light transmittance in the ultraviolet to near-infrared region due to impurities and generation of induced absorption caused by laser irradiation, and laser durability is not impaired.

In the present invention, the concentration (total content) of Ce doped in the synthetic quartz glass is obtained by ICP emission spectroscopy, and the other impurity concentrations are obtained by ICP-MS spectroscopy.

The concentration of Ce ^{4+ in} the doped Ce can be determined by acid decomposition of the sample and oxidation / reduction titration. The concentration of Ce ³⁺ is obtained by subtracting the concentration of Ce ⁴⁺ from the total content of Ce.

On the other hand, it is known that Ce ³⁺ and Ce ⁴⁺ in silica glass have absorption near wavelengths of 320 nm and 250 nm, respectively. Each concentration can also be calculated from the absorbance. Specifically, first, for Ce ³⁺ and Ce ⁴⁺ , the transmittance spectrum when present alone is measured, converted into an absorption spectrum, and the molar extinction coefficient is obtained. Next, the sample was subjected to light transmittance measurement in the wavelength range of 200 nm to 500 nm, the obtained transmittance spectrum was converted into an absorption spectrum, and the peaks were separated into Ce ³⁺ and Ce ⁴⁺ absorption spectra. The concentration of Ce ³⁺ and Ce ⁴⁺ of each sample is calculated from the absorbance at each peak wavelength.

In the synthetic quartz glass for ultraviolet cut filter of the present invention, the density of internal defects of the synthetic quartz glass is preferably 5 × 10 ⁻⁴ pieces / cm ³ or less. If it exceeds 5 × 10 ⁻⁴ pieces / cm ³ , for example, a large glass having a thickness of 400 mm × 400 mm × 10 mm may cause a practical problem and is not suitable for a large filter glass. Moreover, if there are few such internal defects, it will be particularly suitable for use in a high-power laser optical system.

In the present specification, the internal defect is evaluated by visual inspection in a state where the glass surface is mirror-polished using a high-luminance light source having a luminance of 2000 lux or more. In this evaluation, bubbles and foreign matters having a size of 5 μm or more can be detected.

Note that internal defects mean bubbles, metal foreign objects, and striae. If there are bubbles or foreign matter, for example, when a laser or the like is irradiated, damage is caused starting from the foam or foreign matter. In severe cases, the glass may break.

Next, the manufacturing method of the synthetic quartz glass of this invention is demonstrated.
(1) As an example of the manufacturing method of the synthetic quartz glass of this invention, the manufacturing method by the following process is mentioned.

[Porous glass body forming process]
First, a porous glass body forming step is performed in which SiO ₂ glass fine particles obtained by flame hydrolysis of a raw material Si compound are deposited and grown on a substrate to form a porous SiO ₂ glass body.

This porous glass body forming step is a process for obtaining a porous SiO ₂ glass body that has been conventionally used, and may be a method for manufacturing a porous glass body such as a known MCVD method, OVD method, and VAD method. It can be used without particular limitation.

The raw material Si compound used here includes chlorides such as SiCl ₄ , SiHCl ₃ , SiH ₂ Cl ₂ and SiH ₃ Cl, fluorides such as SiF ₄ , SiHF ₃ and SiH ₂ F ₂ , SiBr ₄ and SiHBr _3. Silicon halide compounds such as bromides such as SiI ₄ and iodides such as SiI _4, and R _n Si (OR) _4-n (wherein R is an alkyl group having 1 to 4 carbon atoms, and a plurality of Rs are the same as each other) Or n may be different, and n is an integer of 0 to 3).

[Doping process]
Next, the resulting porous SiO ₂ glass body is made to contain a Ce compound-containing solution, and then a dope step of doping Ce by removing the solvent is performed.

This doping step may be a porous SiO ₂ glass body in such the presence of Ce compound-containing solution, for example, coating a Ce compound containing solution into the porous SiO ₂ glass body, or in contact dripping, spraying, etc. The porous SiO ₂ glass body is immersed in a Ce compound-containing solution.

In this way, it is made to contain a Ce compound containing solution into the porous SiO ₂ glass body, the porous SiO ₂ glass body having a Ce compound is obtained by removing the solvent in the solution. At this time, the solvent may be removed by evaporating the solvent by heating, reducing the pressure, or both. The solvent used here is preferably one that can dissolve the Ce compound and can be easily removed by vaporization, and examples thereof include alcohols such as methanol and ethanol, or pure water.

As Ce compounds, cerium organic compounds such as cerium β-diketone complexes such as cerium alkoxide, cerium carboxylate, cerium acetylacetonate, and halides such as nitrates, hydrochlorides, sulfates and chlorides should be used. Can do.

About the dope process, specifically, the necessary amount calculated from the bulk density of the porous SiO ₂ base material was dissolved so that the cerium chloride hydrate became the target Ce dope amount after vitrification. A method in which the solvent is removed by impregnating the porous SiO ₂ base material into the solution and then heating the base material at 30 to 150 ° C. under a reduced pressure of 1 kPa or less.

[Vitrification process]
Finally, the SiO ₂ porous glass body doped with Ce obtained by the above doping step is heated to the vitrification temperature under a reduced pressure of less than 100 Pa or in an inert atmosphere such as helium to obtain a transparent glass body. A vitrification process is performed.

In this vitrification step, the SiO ₂ porous glass body is vitrified under a reducing atmosphere, and by making such a reducing atmosphere, Ce of the SiO ₂ porous glass body is contained. The valence is suppressed from becoming Ce ⁴⁺ on the oxidation side, and the ratio of Ce ³⁺ increases. Moreover, it is preferable to use a carbon furnace as a method of processing glass under more reducing conditions.

This vitrification is preferably performed under a reduced pressure of 100 Pa or less (preferably under vacuum) or in an inert gas atmosphere of 90% or more, preferably 100% of an inert gas such as He, nitrogen, or argon. . For example, when vitrification is performed in the atmosphere, Ce ⁴⁺ (for example, CeO ₂ ) exists stably, and the synthetic quartz glass of the present invention cannot be obtained. Therefore, when oxygen is contained in the atmosphere, it is preferably less than 20%, more preferably less than 10%, and particularly preferably not contained.

At this time, the transparent vitrification temperature is preferably 1300 to 1550 ° C., and a transparent glass body containing substantially no bubbles or bubbles can be obtained by producing synthetic quartz glass by the above production method.

(2) Next, as another example of the method for producing the synthetic quartz glass of the present invention, a production method according to the following steps may be mentioned.

[Ce-doped porous glass body forming step]
First, a Ce-doped porous glass body forming step is performed in which SiO ₂ glass fine particles obtained by flame hydrolysis of raw material Si compounds and Ce compounds are deposited and grown on a substrate to form a porous SiO ₂ glass body.

Here, by simultaneously subjecting the Si compound and Ce compound to flame hydrolysis, a porous glass molded body doped with Ce can be produced in one step. Except for using a Ce compound to dope Ce, the same operation as in the porous glass body forming step (1) is performed.

Examples of the Ce compound used as a raw material include cerium β-diketone complexes such as cerium alkoxide and cerium acetylacetonate.

[Vitrification process]
Then, the temperature was raised up to vitrification temperature under an inert atmosphere such as under vacuum or helium of less than 100Pa the SiO ₂ porous glass body above Ce-doped Ce obtained by the porous glass body formation step doped The vitrification process which makes a transparent glass body is performed.

This vitrification step may be performed under the same conditions as the vitrification step in the production method (1) above, and a transparent glass body substantially containing no bubbles or bubbles is obtained.

The transparent glass body obtained by the production method of (1) or (2) above is heated to a molding temperature and formed into a desired shape to obtain a molded glass body product. Here, the molding temperature for producing the product is preferably 1600 to 1800 ° C. The obtained glass body is polished as necessary to obtain a final product.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

(Example 1)
SiCl ₄ was flame hydrolyzed by a known flame hydrolysis method (VAD method), and quartz glass fine particles were deposited and grown on a rotating substrate to prepare a porous synthetic quartz glass base material.
A part was cut out from the obtained porous base material so as to have a weight of about 100 g, and the cut out base material was put in a container capable of reducing the pressure to about 1 kPa or less, and the pressure was reduced to 1 kPa or less and held for 2 hours.

Next, a cerium chloride hydrate 0.4% by mass ethanol solution was introduced into the container, the porous body was immersed therein and maintained for 24 hours, and cerium chloride was infiltrated into the inside thereof. Thereafter, the base material was taken out and heated from 30 ° C. to 150 ° C. over 4 days while reducing the pressure in a heatable vacuum furnace, and the base material was dried.

Next, the porous glass base material thus treated was heated to 1450 ° C. in a He atmosphere using an alumina atmosphere furnace to produce a transparent glass body (synthetic quartz glass).

(Example 2)
Glass body (synthetic quartz glass) in the same manner as in Example 1 except that the concentration of cerium chloride hydrate in the ethanol solution was 0.1% by mass and the atmosphere during the transparent vitrification treatment was He / O ₂ (80/20). Manufactured.

(Examples 3 and 4)
A glass body (synthetic quartz glass) was produced in the same manner as in Example 1 except that the transparent vitrification treatment was performed under the reduced pressure of less than 100 Pa by replacing the atmosphere furnace made of alumina with a carbon atmosphere furnace.

(Example 5)
A glass body (synthetic quartz glass) was produced in the same manner as in Examples 3 and 4 except that the concentration of cerium chloride hydrate in the ethanol solution was 1.5% by mass.

(Example 6)
A glass body (synthetic quartz glass) was produced in the same manner as in Example 2 except that the concentration of cerium chloride hydrate in the ethanol solution was 0.2% by mass.

(Example 7)
A glass body (synthetic quartz glass) was produced in the same manner as in Examples 3 and 4 except that the concentration of cerium chloride hydrate in the ethanol solution was 0.2% by mass.

(Example 8)
A glass body (synthetic quartz glass) was produced in the same manner as in Example 2 except that the concentration of cerium chloride hydrate in the ethanol solution was 0.8% by mass.

(Example 9)
A glass body (synthetic quartz glass) was produced in the same manner as in Example 1 except that the concentration of cerium chloride hydrate in the ethanol solution was 0.8% by mass.

(Example 10)
A glass body (synthetic quartz glass) was produced in the same manner as in Example 2 except that the concentration of cerium chloride hydrate in the ethanol solution was 0.05% by mass.

(Example 11)
A glass body (synthetic quartz glass) was produced in the same manner as in Examples 3 and 4 except that the solvent was pure water and the cerium chloride hydrate concentration was 0.7% by mass.

(Example 12)
A glass body (synthetic quartz glass) was produced in the same manner as in Examples 3 and 4 except that the concentration of cerium chloride hydrate in the ethanol solution was 0.6% by mass.

(Test example)
Samples of 15 mm square were cut out from the transparent glass bodies obtained in Examples 1 to 12, and samples for internal transmittance were prepared. The internal transmittance is calculated by adjusting the thickness so that the internal transmittance of light having a wavelength of 351 nm is 5%, and calculating the internal transmittance of light having a wavelength of 375 nm, wavelengths of 400 nm, 532 nm, 666 nm, and 1053 nm. The results are shown in Table 1. At the same time, the Ce concentration in the transparent glass bodies obtained in Examples 1 to 12 and the ratio of Ce ³⁺ in Ce are also shown in Table 1. Furthermore, the obtained transparent glass body was visually inspected for defects. In Examples 1, 2, 3, 4, 7, and 9 to 12, no defect was observed. On the other hand, all of Examples 5, 6 and 8 were too cloudy and cloudy, and could not be inspected.

* 1 Internal transmittance: Samples of any two types of 15 mm square thickness are prepared from the manufactured glass body and evaluated using an ultraviolet-visible near-infrared spectrophotometer (trade name: LAMBDA 950, manufactured by PerkinLmer). did. The sample thickness was adjusted so that the internal transmittance of light at a wavelength of 351 nm was 5%. The thickness at this time is shown in Table 1 as “thickness t5 (mm) at which the internal transmittance of light is 5% at 351 nm”, and the internal transmittance (%) of light at each wavelength at the thickness was obtained.
Specifically, glass samples were prepared by optically polishing two surfaces of two types of arbitrary thicknesses of 15 mm in length, 15 mm in width, and 1 to 10 mm in thickness. The light transmittance T1, T2 of the two types of 351nm of sample thickness t1 and the thickness t2 is applied to Equation (1), the thickness t5 (mm) such that the internal transmittance T _lambda is 5% at a wavelength of 351nm Asked. Further, in the thickness is the calculated t5 (mm), the internal transmittance T _lambda of other wavelengths was determined by equation (1).
T _λ (% / t5 mm) =
exp (ln (T1 / T2) / (t2-t1) × t5) × 100 (1)

* 2 Ce concentration (mass%): Ce concentration was calculated by ICP emission spectrometry.
* Ratio of 3 ^{Ce 3+} ^[Ce 3+ / Ce] (%): to calculate the concentration of ^{Ce 3+} and ^{Ce 4+} by measuring the transmittance spectrum by the method mentioned above, to calculate the percentage of ^{Ce 3+} in the Ce.

As described above, the synthetic quartz glass for ultraviolet cut filter according to the present invention has an excellent ultraviolet shielding effect, and also has good transmittance of near infrared light and visible light, and a semiconductor using a high output laser. It has been found suitable for lithographic techniques for manufacturing.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2010-159941 filed on Jul. 14, 2010, the contents of which are incorporated herein by reference.

The synthetic quartz glass for ultraviolet cut filter of the present invention can be suitably used for preventing damage to optical parts due to ultraviolet rays in lithography technology for semiconductor production using a high-power laser. In addition, it can be widely used as glass for ultraviolet cut filters.

Claims

A synthetic quartz glass doped with 0.015 mass% or more and less than 0.4 mass% of Ce,
90% or more of the doped Ce exists in a state of Ce 3+ , synthetic quartz glass for an ultraviolet cut filter.
When the thickness of the quartz glass for ultraviolet cut filter is adjusted so that the internal transmittance of light having a wavelength of 351 nm is 5%, the internal transmittance of light having a wavelength of 375 nm is 50% or more, and the internal transmission of light having a wavelength of 400 nm is performed. 2. The synthetic quartz glass for ultraviolet cut filter according to claim 1, wherein the transmittance is 90% or more and the internal transmittance of light in the wavelength region of 500 to 1100 nm is 95% or more.
3. The synthetic quartz glass for ultraviolet cut filter according to claim 1, wherein the density of internal defects of the synthetic quartz glass is 5 × 10 −4 pieces / cm 3 or less.
The thickness of the synthetic quartz glass for an ultraviolet cut filter is 5 mm to 45 mm when the thickness is adjusted so that the internal transmittance of light having a wavelength of 351 nm is 5%. Synthetic quartz glass for UV cut filter.
The synthetic quartz glass for an ultraviolet cut filter according to any one of claims 1 to 4, wherein the synthetic quartz glass is used for transmission of a high-power laser.
A porous glass body forming step of depositing and growing SiO 2 glass fine particles obtained by flame hydrolysis of a raw material Si compound on a base material to form a porous SiO 2 glass body;
After the Ce compound-containing solution is contained in the obtained porous SiO 2 glass body, a Ce doping step of doping Ce by removing the solvent,
Vitrification step of obtaining a transparent glass body by heating the Ce-doped SiO 2 porous glass to a vitrification temperature under a reduced pressure of less than 100 Pa or under an inert gas atmosphere;
A method for producing synthetic quartz glass, comprising:
Ce-doped porous glass body forming step for forming porous SiO 2 glass body doped with Ce by depositing and growing SiO 2 glass fine particles obtained by flame hydrolysis of raw material Si compound and Ce compound When,
A vitrification step of obtaining a transparent glass body by heating the Ce-doped porous SiO 2 glass body to a vitrification temperature under a reduced pressure of less than 100 Pa or in an inert gas atmosphere. Glass manufacturing method.