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Optical glass

A technology of optical glass and optical constants, applied in optics, optical components, instruments, etc., can solve problems such as blurring, easy fusion and adhesion of metal molds, and inappropriate optical glass, etc., and achieve low cost and good devitrification resistance.

Inactive Publication Date: 2003-01-08
OHARA
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

However, glass containing PbO tends to melt and adhere to the metal mold during molding, so repeated use of the metal mold is difficult, so it can be said that it is not suitable as an optical glass for molding.
In addition, containing F 2 The composition of the glass is due to the selective volatilization of F from the surface layer of the glass melt when the preform is formed. 2 composition, the preform produces blurring, or when molding the preform, the F 2 The component volatilizes and adheres to the metal mold, and the surface of the metal mold is blurred, so it is not suitable as an optical glass for molding.

Method used

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Examples

Experimental program
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Embodiment approach

[0037] Examples of the present invention are described below, but the present invention is not limited to these Examples.

[0038] Tables 1 to 4 show the compositions of Examples (No. 1 to 26) and Comparative Examples (A to E) of the optical glass for precision press molding of the present invention, and show the compositions of the glasses obtained in each of the Examples and Comparative Examples. Refractive index (n d ), Abbe number (ν d ), transformation point (Tg), yield point (At) and temperature difference between yield point and transformation point (At-Tg).

[0039] For the optical glasses for molding of Examples Nos. 1 to 26 and the optical glasses of Comparative Examples A to E, common optical glass raw materials such as mixed oxides, carbonates and nitrates were weighed in a prescribed ratio so as to reach the Each composition ratio shown is then put into a platinum crucible, etc., and melted at a temperature of 1000 to 1300°C for 2 to 5 hours according to the deg...

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PUM

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Abstract

There is provided an optical glass suitable for precision mold pressing having optical constants of a refractive index (nd) within a range from 1.75 to 1.85 and an Abbe number ( nu d) within a range from 35 to 45, comprising in mass % on oxide basis: having a transition point (Tg) within a range from 500 DEG C to 590 DEG C and a yield point (At) within a range from 530 DEG C to 630 DEG C, and being free from devitrification in a devitrification test conducted under a condition of 950 DEG C / 2 hours.

Description

technical field [0001] The present invention relates to having refractive index (n d ) is 1.75~1.85 and the Abbe number (ν d ) is an optical glass suitable for precision molding (precision mold press) molding with an optical constant in the range of 35 to 45. Background technique [0002] In recent years, the miniaturization and weight reduction of optical devices has been remarkably advanced, and aspheric lenses have been widely used in order to reduce the number of lenses constituting the optical system of the optical device. The mainstream aspheric lens manufacturing method is to heat and soften a preform obtained from a gob or a glass blank, press it with a high-precision metal mold, and copy the surface of the metal mold. The aspherical lens obtained by this method does not require grinding or grinding or basically does not require grinding or grinding, and molded products of desired shapes can be produced with high production efficiency. Glass precision press moldin...

Claims

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Application Information

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IPC IPC(8): G02B1/00C03C3/068
CPCC03C3/068
Inventor 上原进
Owner OHARA
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