32results about How to "Excellent glass stability" patented technology

Provided is an optical glass comprising, denoted as molar percentages:

• • 10 to 20 percent SiO₂,
  • 5 to 40 percent B₂O₃,
  • SiO₂+B₂O₃=15 to 50 percent,
  • 0 to 10 percent Li₂O,
  • 12 to 36 percent ZnO,
  • where 3×Li₂O+ZnO≧18 percent,
  • 5 to 30 percent La₂O₃,
  • 0 to 20 percent Gd₂O₃,
  • 0 to 10 percent Y₂O₃,
  • La₂O₃+Gd₂O₃=10 to 30 percent,
  • La₂O₃/SIGMA(Σ)RE₂O₃=0.67 to 0.95
  • (where SIGMA(Σ)RE₂O₃=La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Sc₂O₃+Lu₂O₃),
  • 0.5 to 10 percent ZrO₂,
  • 1 to 15 percent Ta₂O₅,
  • 1 to 20 percent WO₃,
  • Ta₂O₅/WO₃≦2.5 (molar ratio),
  • 0 to 8 percent Nb₂O₅,
  • 0 to 8 percent TiO₂; and
  • having a refractive index nd of not less than 1.87 and
  • an Abbé number nu(v)d of not less than 35 but less then 40.

A method for manufacturing a preform for precision press molding by separating a glass melt gob from a glass melt obtained by mixing, heating, and melting glass starting materials, and forming a preform in a glass melt gob cooling step, said mixing, heating, and melting of glass starting materials is conducted so as to obtain the above optical glass.

The optical glass of the present invention has a refractive index n_d of 1.70 or greater and an Abbé number of 50 or greater. Given as mole percentages, it comprises:

with the combined quantity of the above components being 97 percent or greater. The molar ratio of {ZnO/(La₂O₃+Gd₂O₃+Y₂0₃)} is 0.8 or less and the molar ratio of {+SrO+BaO)/(La₂O₃+Gd₂O₃+Y₂0₃)} is 0.8 or less. Ta₂O₅ may be incorporated as an optional component, with the molar ratio {(ZrO₂+Ta₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃)}being 0.4 or less. The present invention further relates to a preform for precision press molding comprised of this glass, an optical element comprised of this glass, and methods of manufacturing the same.

An optical glass comprising, by mol %,

• • 0.1 to 40% of SiO₂,
  • 10 to 50% of B₂O₃,
  • 0 to 10% of total of Li₂O, Na₂O and K₂O,
  • 0 to 10% of total of MgO, CaO, SrO and BaO,
  • 0.5 to 22% of ZnO,
  • 5 to 50% of La₂O₃,
  • 0.1 to 25% of Gd₂O₃,
  • 0.1 to 20% of Y₂O₃,
  • 0 to 20% of Yb₂O₃,
  • 0 to 25% of ZrO₂,
  • 0 to 25% of TiO₂,
  • 0 to 20% of Nb₂O₅,
  • 0 to 10% of Ta₂O₅,
  • over 0.1% but not more than 20% of WO₃,
  • 0 to less than 3% of GeO₂,
  • 0 to 10% of Bi₂O₃, and
  • 0 to 10% of Al₂O₃,
  • the mass ratio of the content of SiO₂ to the content of B₂O₃, SiO₂/B₂O₃, being 1 or less,
  • the optical glass having a refractive index nd of 1.86 to 1.95 and an Abbe's number νd of (2.36−nd)/0.014 or more but less than 38.

An optical glass has a low glass transition temperature (Tg) and optical constants in which a refractive index (n_d) is in the range of from 1.70 to less than 1.74 and an Abbe number (ν_d) is between 40 and 45 (excluding 40 and 45), has a content of SiO₂ is 17% by mass or less, a glass transition temperature (Tg) is 540° C. or less, and a weathering resistance (surface-method) in Class 1 or 2, and has excellent chemical durability, particularly weathering resistance (surface-method) and is appropriate for precision mold press forming.

An optical glass of the present invention has optical constants with a refractive index (nd) of 1.74 to 1.76 and an Abbe number (υd) of 45 to 49.5, contains SiO₂, B₂O₃, BaO, ZnO, La₂O₃, Gd₂O₃, TiO₂, Al₂O₃, and Li₂O as essential components, does not contain Ta₂O₅, GeO₂, or ZrO₂ which usually affects the stabilization of glass, does not contain lead, arsenic, or fluorine having adverse effects on the environment, and has a glass transition point Tg of 530 to 590° C.

According to the present invention, a stable glass for precision press-molding can be provided which has a low glass transition temperature (Tg), has a high refractive index and a low dispersion property, and does not contain expensive Ta₂O₅, GeO₂, ZrO₂, or Y₂O₃.

The present invention provides an optical glass, containing, in % by weight on an oxide basis, 30 to 50% of P₂O₅, 18 to 43% of BaO, 2 to 12% of B₂O₃, 1.4 to 5% of Al₂O₃, more than 0 to 6% of Li₂O, more than 0 to 9% of La₂O₃, 0.1 to 8% of MgO, 0 to 10% of CaO, 0 to 15% of SrO, 0 to 5% of ZnO, 0 to 7% of Gd₂O₃, and 0 to 3% of SiO₂, and having optical constants of a refractive index n_d of 1.59 to 1.63 and an Abbe number ν_d of 63 to 68.

An aspect of the present invention relates to optical glass, which is oxide glass, having a refractive index nd ranging from 1.95 to 2.50 and an Abbé number νd ranging from 18 to 40, including essential components in the form of Si⁴⁺, B³⁺, La³⁺, Ti⁴⁺, Nb⁵⁺, and at least one from among Gd³⁺, Y³⁺, and Yb³⁺, including, denoted as cation %, 1 to 30% of Si⁴⁺, 1 to 50% of B³⁺, wherein a total of Si⁴⁺ and B³⁺ ranges from 5 to 55%, a total of 11 to 70% of La³⁺, Gd³⁺, Y³⁺, and Yb³⁺, with 10 to 50% of La³⁺, a total of 23 to 70% of Ti⁴⁺, Nb⁵⁺, Ta⁵⁺, and W⁶⁺, with equal to or greater than 1% of Nb⁵⁺ and greater than 22% of Ti⁴⁺.

A P₂O₅—BaO—ZnO—Nb₂O₅ type optical glass contains 25-50 wt. % P₂O₅, 15-35 wt. % BaO, 1-25 wt. ZnO, and 3-10 wt. % Nb₂O₅. The optical glass has a high refractive index (particularly preferably the refractive index n_d of 1.6 or more), low dispersion (an Abbe number υ_d of 42 or more), a low deformation point, and improved resistance to devitrification upon molding, and is suitable for precision-mold press molding or other molding processes and also suitable for transfer of a fine structure.

Provided is a near-infrared light absorbing glass with a near-infrared light absorbing element and a near-infrared light absorbing filter. When the length of the near-infrared light absorbing glass is 1 mm, transmissivity is more than 80% at the wavelength of 400 nm, and more than 85% at the wavelength of 500 nm. The near-infrared light absorbing glass contains P⁵⁺, Al³⁺, Li⁺, R²⁺ and Cu²⁺ represented by positive ions, wherein R²⁺ represents Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺. Meanwhile, the near-infrared light absorbing glass contains O²⁻ and F⁻ represented by negative ions. Water durability (D_W) of the near-infrared light absorbing glass reaches Class 1 and acid durability (D_A) reaches above Class 4. In this invention, fluorphosphate glass is used as the matrix glass and the components are designed specially, so that the melting temperature of glass can be effectively lowered and the chemical stability of the glass can be excellent.