EP0483752A2
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EP
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Optical member made of high-purity and transparent synthetic silica glass and method for production thereof and blank thereof
Assignee: Heraeus Quarzglas GmbH and Co KG
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Filing: 1991-10-29
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Granted: —
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Expires: 2011-10-29
Abstract
Abstract This invention relates to an optical member made of synthetic silica glass of high-purity and transparency, and a method for manufacture a blank thereof or the optical member, and more especially to optical members assembled in assembled in various apparatus employing such high-power laser beams as an excimer laser. The optical member comprising: having absolute refractive index, nd, of 1.460 or more, and having hydrogen molecule concentration of about 5 x 10<1><6> molecules/cm<3> or more.
Inventors
- 👤 Shigeru Yamagata
- 👤 Michiyou Kuriyama
- 👤 Kyoichi Inaki
- 👤 Ralf Takke
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 10:13
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/708; G03F7/7095; G03F7/70958; C; C03; C03B; C03B19/00; C03B19/14; C03B19/1453; C03B32/00; C03C; C03C3/00; C03C3/04; C03C3/06; C03C4/00; C03C4/0071; G02; G02B; G02B1/00; G03F7/70216; G03F7/70241; H; H01; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/034; C03B2201/00; C03B2201/06; C03B2201/07; C03B2201/20; C03B2201/21; C03B2201/23; C03C2201/00; C03C2201/06; C03C2201/20; C03C2201/21; C03C2201/23; C03C2203/00; C03C2203/10; C03C2203/50; C03C2203/52; C03C2203/54; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10S501/00; Y10S501/90; Y10S501/905
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
39 words
In an optical member made of high-purity transparent synthetic silica glass, the optical member comprising: having absolute refractive index, n d , of 1.460 or more, and having hydrogen molecule concentration of about 5 x 10¹⁶ molecules/cm³ or more.
Claim 2
Dependent Claim
30 words
An optical member as claimed in claim 1, for use with ultraviolet laser, wherein the hydrogen molecule concentration in the optical member is about 1 x 10¹⁷ molecules/cm³ or more.
Claim 3
Dependent Claim
40 words
An optical member as claimed in claim 1, wherein the optical member is made from a lump of high-purity transparent synthetic silica glass as a starting material, in which the silica glass is synthesized by the oxyhydrogen flame hydrolysis method.
Claim 4
Dependent Claim
20 words
An optical member as claimed in claim 1, wherein the optical member contains rare gas elements together with hydrogen molecules.
Claim 5
Dependent Claim
102 words
An optical member as claimed in claim 1, wherein each of intensity ratios R₁ and R₂ of the optical member is respectively smaller than 0.48 and 0.15 in which the intensity ratio R₁ is a ratio of scattering peak intensity I₁ at wave numbers of 495 cm⁻¹ by scattering peak intensity I₀ at wave numbers of 800 cm⁻¹ for the basic vibration between silicon and oxygen measured by the laser Raman scattering spectrometry, and in which the scattering ratio R₁ is a ratio of scattering intensity I₂ at wave numbers of 606 cm⁻¹ by the scattering intensity I₀ for the basic vibration.
Claim 6
Dependent Claim
39 words
An optical member as claimed in claim 1, wherein the maximum refractive index fluctuation, δn, of the optical member along the incident of light is less than 5 x 10⁻⁶, or more preferably is less than 2 x 10⁻⁶.
Claim 7
Dependent Claim
32 words
An optical member as claimed in claim 1, wherein the concentration of chlorine in the optical member is less than 500 mass ppm, or more preferably is less than 200 mass ppm.
Claim 8
Dependent Claim
21 words
An optical member as claimed in claim 1, wherein the optical member is free from striae at least in one direction.
Claim 9
Dependent Claim
28 words
An optical member as claimed in claim 1, wherein the birefringence of the optical member is less than 10 nm/cm, or more preferably is less than 5 nm/cm.
Claim 10
Dependent Claim
15 words
An optical member as claimed in claim 1, wherein the optical member contains OH group.
Claim 11
Dependent Claim
38 words
An optical member as claimed in claim 1, for use with the high-power ultraviolet laser having a wave length less than about 250 nm, wherein the OH group concentration is at least about 10 mass ppm or more.
Claim 12
Dependent Claim
62 words
An optical member as claimed in claim 1, wherein the impurity content in the optical member is such that the total amount of Li, Na and K is 300 mass ppb or less, the total amount of Mg, and Ca is 200 mass ppb or less, the total amount of Ti, Cr, Fe, Ni and Cu is 500 mass ppb or less.
Claim 13
Dependent Claim
45 words
An optical member as claimed in claim 1, wherein the high-power light source is either one of a YAG laser (1064 nm), a He-Ne laser (633 nm), an Ar laser (from 350 to 515 nm), a KrF laser (248 nm) or an ArF excimer laser.
Claim 14
Dependent Claim
53 words
An optical member as claimed in claim 1, wherein the optical member is either one of a lens, a prism, a filter, a window, a mirror, a light transmission member or a semifinished product thereof used in optical apparatus that uses an excimer laser, a YAG harmonics laser, or other high-power ultraviolet lasers.
Claim 15
Dependent Claim
52 words
An optical member as claimed in claim 1, wherein the optical member is either one of a lens, a prism, a filter, a window, a mirror, a light transmission member or a semifinished product thereof placed in an environment where it is exposed to gamma rays, X-rays, cosmic rays or other radiation.
Claim 16
Dependent Claim
86 words
A laser optical apparatus comprising an optical member made of a transparent synthetic silica glass member having a refractive index, n d , of 1.460 or more, containing hydrogen molecules in an amount at least about 5 x 10¹⁶ molecules/cm³, wherein the optical member is intended to be irradiated with a light source either one of a YAG laser (1,064 nm), a He-Ne laser (633 nm), an Ar laser (from 350 to 515 nm), a KrF laser (248 nm), or an ArF excimer laser (193 nm).
Claim 17
Dependent Claim
71 words
A laser optical apparatus comprising an optical member made of a transparent synthetic silica glass member having a refractive index, n d , of 1.460 or more, containing hydrogen molecules in an amount at least about 5 x 10¹⁶ molecules/cm³, wherein the laser optical apparatus uses with an excimer laser as a light source which irradiates a high-power laser beam having an energy density more than about 10 mj/cm² per pulse.
Claim 18
Independent Claim
73 words
A method of producing an optical member, the method comprising the steps of: using a lump of synthetic silica glass as a starting material, heating the silica glass at a temperature possible to remelt the silica glass in a high-pressure atmosphere of rare gas at an elevated temperature, keeping the atmosphere for a desirable period to contain hydrogen until the concentration of molecules in the silica glass is above 5 x 10¹⁶ molecules/cm³.
Claim 19
Dependent Claim
78 words
A method of producing an optical member as claimed in claim 18, further comprising after the remelting the lump of silica glass in the high-pressure atmosphere of rare gas or of main composition thereof, cooling slowly at least to a temperature of 900°C under the high-pressure atmosphere, cooling further at least to a temperature of 500°C under a high-pressure atmosphere, whereby the generation of strains in the glass is suppressed, and hydrogen molecules are included in the glass.
Claim 20
Dependent Claim
30 words
A method of producing an optical member as claimed in claim 18, wherein the lump of synthetic silica glass is a silica glass material synthesized by the oxyhydrogen flame hydrolysis.
Claim 21
Dependent Claim
42 words
A method of producing an optical member as claimed in claim 18, wherein the temperature possible to remelt the silica glass in the heating step is higher than 1,600°C, and wherein the pressure in the heating step is more than 1,000 kgf/cm².
Claim 22
Dependent Claim
38 words
A method of producing an optical member as claimed in claim 18, wherein the temperature possible to melt the silica glass in the heating step is higher than the softening point whose viscosity as log n is 7.6.
Claim 23
Dependent Claim
32 words
A method of producing an optical member as claimed in claim 19, wherein the pressure in the high-pressure atmosphere cooled at least to the temperature of 500°C is 500 kgf/cm² or more.
Claim 24
Dependent Claim
74 words
In a method of producing an optical member or a blank thereof made of transparent synthetic silica glass, the method comprising the steps of: using a lump of synthetic silica glass as a starting material, heating the silica glass in a high-pressure atmosphere of rare gas or main composition thereof at an elevated temperature, keeping the atmosphere for a desirable period, cooling slowly at least to a temperature of 900°C under a high-pressure atmosphere.
Claim 25
Dependent Claim
48 words
A method of producing an optical member or a blank thereof as claimed in claim 24, wherein a high-homogeneous silica glass material of high-purity, and being free from striae in at least one direction is used for the lump of transparent synthetic silica glass as the starting material.
Claim 26
Dependent Claim
40 words
A method of producing an optical member or a blank thereof as claimed in claim 24, wherein the temperature for the heating step is 1,000°C or more, and wherein the pressure for the heating step is at least 1,000 kgf/cm².
Claim 27
Dependent Claim
35 words
A method of producing an optical member or a blank thereof as claimed in claim 24, wherein the pressure in the atmosphere cooled at least to a temperature of 500°C is higher than 500 kgf/cm².
Claim 28
Dependent Claim
38 words
A method of producing an optical member or a blank thereof as claimed in claim 18, wherein the material of vessel to place the silica glass for remelting is either one of tungsten, tantalum, platinum-rhodium alloys or refractories.
Claim 29
Dependent Claim
45 words
A method of producing an optical member or a blank thereof as claimed in claim 24, wherein, in a cooling step after the high-pressure heating step, a cooling rate to cool slowly in a range of temperatures from 1,200 to 900°C is 100°C/hr or less.
Claim 30
Dependent Claim
26 words
An optical member as claimed in claim 1, wherein the materials stoichiometry is set to SiO 2+x with x in the range of +0.0001 to -0.001.
References Cited (Backward Citations)
No citation records indexed.
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