Precision press-molding glass preform, optical element and processes for the production thereof

A technology of optical components and preforms, applied in optical components, glass manufacturing equipment, glass pressing, etc.

Active Publication Date: 2005-03-09
HOYA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The problem with the above optical glass is that it needs to add harmful PbO to it to increase its refractive index

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-39

[0225] Weighing oxides, carbonates, sulfates, nitrates, hydroxides, etc., such as SiO 2 、H 3 BO 3 , La 2 o 3 , ZnO, ZnCO 3 , ZrO 2 , Li 2 CO 3etc. as raw materials to obtain 250-300 grams of glass compositions shown in Table 1-1 to Table 1-4. The raw materials weighed in each embodiment are fully mixed to obtain the formulated batch material, and the formulated batch material is placed in a platinum crucible, and the crucible is placed in an electric furnace maintained at 1200-1450 ° C, and the formulated batch material is stirred in the air Melt for 2-4 hours. After melting, the molten glass is cast in a carbon mold of 40×70×15 mm. After the molten glass is gradually cooled to the glass transition temperature, the glass in the mold is immediately placed in an annealing furnace. The glass is annealed in the glass transition temperature range for about 1 hour and cooled in a furnace to obtain an optical glass. When the obtained optical glass was observed with a micros...

Embodiment 40

[0238] Each of the glass preforms obtained in the above-mentioned Examples 1-39 was separately fed into a press mold provided with a carbon-containing film (diamond-type carbon) on the molding surface, and the glass preform and the press mold were heated together until A temperature is reached that gives the glass a viscosity of 105-109. Precise compression molding of the glass preform is carried out with a compression mold under a nitrogen atmosphere with a pressure of 5-15Mpa, and the pressurization time is 10-300 seconds. The precision molded product thus obtained is annealed to obtain an aspherical lens. The resulting lens has a refractive index (nd) and an Abbe's number (vd) equal to those of the corresponding optical glass forming the above-mentioned glass preform.

[0239] According to the above-mentioned method, the shape of the stamper and the weight of the glass preform are determined as required, and in each of the above-mentioned embodiments, various lenses such a...

Embodiment 41

[0241] Each of the glass preforms in Examples 1-39 was preheated to allow the glass to develop 10 4 -10 8 Viscosity temperature, and it is introduced into a SiC stamper preheated to a temperature lower than the above-mentioned preheating temperature and having a molding surface provided with a carbon-containing film (diamond-type carbon film). Precise compression molding of the glass preform is carried out with a compression mold under a nitrogen atmosphere with a pressure of 5-15Mpa, and the pressurization time is 10-300 seconds.

[0242] An aspheric lens was obtained by annealing the thus obtained precise press-molded product. The resulting lens has a refractive index (nd) and an Abbe's number (vd) equal to those of the corresponding optical glass forming the above-mentioned glass preform.

[0243] According to the above-mentioned method, the shape of the stamper and the weight of the glass preform are determined as required, and in each of the above-mentioned embodiments,...

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Abstract

Provided is a precision press-molding glass preform, which is formed of a high-refractivity low-dispersion optical glass containing no PbO and which requires none of cutting and polishing of an optical-function surface after the precision press-molding is carried out, the optical glass containing, by mol%, 40 to 60 % of B2O3 exclusive of 40 %, 5 to 25 % of La2O3, 2 to 22 % of Gd2O3, 5 to 45 % of ZnO and 0 to 10 % of SiO2 exclusive of 10 % as glass components but containing no PbO, wherein the ratio of the content of B2O3 to the total content of B2O3 and SiO2 (B2O3 / (B2O3+SiO2)) is over 0.84 but not more than 1.00, and the ratio of the content of Gd2O3 to the total content of Gd2O3 and Nb2O5 as an optional component (Gd2O3 / (Gd2O3+Nb2O5)) is over 0.91 but not more than 1.00, the optical glass having a refractive index (nd) of over 1.80 but not more than 2.00 and an Abbe's number ( nu d) of 40 to 45 exclusive of 45.

Description

field of invention [0001] The present invention relates to a precision press molded glass article, a method of producing such a glass article, an optical element and a method of producing such an optical element. The invention can be used, for example, in the production of super-precision aspheric mirrors, super-precision spherical lenses or similar optical elements. Background technique [0002] In recent years, with the advent of digital cameras, machines and equipment using optical systems have rapidly improved in terms of integration and functionality. Under such circumstances, it is increasingly required to improve the precision of the optical system and reduce its weight and size. To meet this need, optical designs using aspheric mirrors are becoming mainstream. [0003] The key to providing high-volume, low-cost aspheric mirrors made of high-refractive index and low dispersion or advanced functional glass with high refractive index and high dispersion is the ability...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C03C3/068C03C3/15
CPCC03C3/15C03C3/068G02B3/00
Inventor 林和孝
Owner HOYA CORP
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