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Optical member of synthetic quartz glass for excimer lasers and method for producing same

Patent 5364433 Issued on November 15, 1994. Estimated Expiration Date: Icon_subject May 15, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

Method for producing silica glass Patent #: 4317668
Issued on: 03/02/1982
Inventor: Susa ,   et al.

Inventors

Assignee

Application

No. 977397 filed on 05/15/1993

US Classes:

65/17.4, Including flame or gas contact501/54, More than 90 percent by weight silica501/900OPTICAL GLASS (E.G., SILENT ON REFRACTIVE INDEX AND/OR ABBE NUMBER)

Examiners

Primary: Bell, Mark L.
Assistant: Bonner, C. M.

Attorney, Agent or Firm

Foreign Patent References

  • 58-161937 JP. 09/13/1983
  • 59-92941 JP. 05/13/1984
  • 61-251538 JP. 11/13/1986
  • 100436 JP 05/13/1987
  • 2-69332 JP. 03/13/1990
  • 80343 JP 03/13/1990
  • 34419 JP 02/13/1991

International Class

C03C 003/06

Foreign Application Priority Data

1991-06-29 JP

Abstract

A synthetic quartz glass optical member for an ultraviolet laser, suitably applicable as a stepper lens of a lithographer using an excimer laser beam and other optical members, wherein the quartz glass has a hydroxyl content of 10 to 100 ppm, a chlorine content of 200 ppm or less, a hydrogen content of 1×1016 molecules/cm3 or less, a homogeneity of refractive index of 5×10-6 or less in terms of Ɗn, and a birefringence of 5 nm/cm or less. The optical member can be produced by subjecting a volatile silicon compound to flame hydrolysis with oxyhydrogen flame, depositing the formed particulate silica on a heat-resistant support to prepare a porous silica matrix, heating the matrix in a vacuum as high as 1×10-2 Torr or above to a temperature of 1,400 ° C. or above to effect dehydration and degassing, homogenizing the resultant transparent quartz glass into highly homogeneous quartz glass free from striae in at last one direction, molding the highly homogeneous quartz glass, and annealing the molded glass.

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