Optical glass

A technology of optical glass and glass block, applied in optics, optical components, optical surface grinders, etc., can solve the problems of glass stability decline, devitrification, increase, etc., and achieve the effect of excellent glass stability and high refractive index

Active Publication Date: 2009-12-30
HOYA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the high refractive index and low dispersion glass has a relatively large amount of high refractive index imparting components and a relatively small amount of glass network forming components, so there are problems such as decreased glass stability and easy devitrification during the manufacturing process.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0167] First, in order to obtain oxide glass Nos. 1 to 36 having the composition shown in Table 1-1 to Table 1-4 (expressed in cation %), nitrate, sulfate, hydroxide, and oxide The raw material, boric acid, etc., are weighed and mixed thoroughly to form a blended raw material. The blended raw material is put into a platinum crucible and heated, melted, clarified, and stirred at 1400°C to form a uniform melt. glass. This molten glass was poured into a preheated mold, quenched, and then maintained at a temperature near the glass transition temperature for two hours, and then slowly cooled to obtain oxide glass Nos. 1 to 36. No precipitation of crystals was observed in any glass.

[0168] In addition, the anion components of oxide glass Nos. 1 to 36 are all O 2- . In addition, Table 2-1 to Table 2-3 are compositions represented by mass% of oxide glass Nos. 1 to 36, and Tables 3-1 to 3-3 are compositions represented by mol %.

[0169] The characteristics of each glass were measured by...

Embodiment 2

[0205] Next, the glass block for press molding formed from each optical glass of Example 1 was manufactured as follows.

[0206] First, in order to obtain each of the above-mentioned glasses, the glass raw materials are blended, put into a platinum crucible, and heated, melted, clarified, and stirred to obtain a uniform molten glass. Next, the molten glass flows out from the outflow pipe at a constant flow rate, and is cast into a mold arranged horizontally below the outflow pipe to shape a glass plate having a certain thickness. The formed glass sheet is continuously drawn in the horizontal direction from the opening provided on the side surface of the mold, and is transported to the annealing furnace by a belt conveyor, where it is slowly cooled.

[0207] The slowly cooled glass plate is cut or cut to produce glass pieces, and these glass pieces are barrel-milled to become glass blocks for press molding.

[0208]In addition, a cylindrical mold is placed below the outflow pipe, m...

Embodiment 3

[0210] The molten glass flows out from the outflow pipe in the same manner as in Example 2. After the lower end of the outflowing molten glass is caught by the forming die, the forming die is urgently lowered, the flow of molten glass is cut off by surface tension, and the desired amount of molten glass is obtained on the forming die. Piece. Then, when gas is blown from the forming mold and upward wind pressure is applied to the glass to float it, the glass is formed into a glass block, and the glass block is taken out from the forming mold and annealed. Then, the glass block is barrel-milled to become a glass block for press molding.

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PUM

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Abstract

The invention provides an optical glass having a very high refractive index in spite of its low-dispersion property, having excellent glass stability and having less susceptibility to coloring. An optical glass is an oxide glass and is characterized in that the optical glass comprises, by cationic %, 0 to 30% of Si<4>, 10 to 55% of B<3>, less than 5% of total of Li<>, Na<> and K<>, less than 5% of total of Mg<2>, Ca<2> and Sr<2>, 0 to 8% of Ba<2>, 0.1 to 15% of Zn<2>, 10 to 50% of La<3>, 0 to 20% of Gd<3>, 0 to 15% of Y<3>, 0 to 10% of Yb<3>, 0 to 20% of Zr<4>, 0.1 to 22% of Ti<4>, 0 to 20% of Nb<5>, 0 to 8% of Ta<5>, 0 to 5% of W<6>, 0 to 8% of Ge<4>, 0 to 10% of Bi<3>, and 0 to 10% of Ai<3>, the cationic ratio of the content of Si<4> to the content of B<3>, Si<4> / B<3>, being less than 1.0, the total content of Nb2O5 and Ta2O5 as oxides being less than 14 mass %, the optical glass having a refractive index nd of 1.92 to 2.2 and an Abbe's number nud of 25 to 45.

Description

Technical field [0001] The present invention relates to an optical glass having high refractive index and low dispersion characteristics, a glass block for press molding and an optical element formed from the optical glass, a method for manufacturing the same, and a method for manufacturing an optical element blank. Background technique [0002] By combining a lens formed of high refractive index and low dispersion glass with a lens formed of ultra-low dispersion glass, chromatic aberration can be corrected and the optical system can be miniaturized. Therefore, it occupies a very important position as an optical element constituting a projection optical system such as an imaging optical system or a projector. [0003] Patent Document 1 discloses such a high refractive index low dispersion glass. [0004] Patent Document 1: Japanese Patent Application Laid-Open No. 55-60039. Summary of the invention [0005] However, the amount of the high refractive index imparting component of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C03C3/068C03C3/253C03C3/155G02B1/00B24B13/00
CPCC03C3/068
Inventor 根岸智明邹学禄
Owner HOYA CORP
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