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Process for making a coated optical article free of visible fining lines

a coating and optical article technology, applied in the field of coating optical articles, can solve the problems of significant surface roughness of the treated face of the transparent lens blank, and achieve the effect of good optical quality

Inactive Publication Date: 2005-06-30
ESSILOR INT CIE GEN DOPTIQUE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention provides a process for making a coated optical article free of visible fining lines, where the coating has a thickness of 50 μm or less and the difference in refractive index values between the coating and the lens blank is up to 0.1. The process involves depositing a liquid curable coating composition on the fined but unpolished main surface of the optical article or the internal surface of the mold part, and then applying pressure to spread the coating and form a uniform layer on the main surface. The process can be used for making a coated article with a polished surface state. The invention also provides a process for making a coated lens blank, where the main surface has been fined but unpolished. The lens blank can be a fined but unpolished lens blank or a conventionally coated lens blank that has been previously coated with a thin coating film of less than 5 μm. The process is particularly useful for lenses that have been coated using conventional processes and has a thin coating film of less than 2 μm.

Problems solved by technology

Fine grinding (fining), performed after grinding further changes the geometry of the treated face of the lens blank but can lead to a translucent lens blank whose treated face still shows significant surface roughness.

Method used

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  • Process for making a coated optical article free of visible fining lines
  • Process for making a coated optical article free of visible fining lines
  • Process for making a coated optical article free of visible fining lines

Examples

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Effect test

example 1

[0130] A semi-finished lens SF lens made of diéthyleneglycol bis-allyl carbonate copolymer (CR-39®) was generated by V-95 and fined with 15 μm pad to a −1.25 power lens (back curvature 5.0 base, diameter 70 mm) without polishing. Fining process is done with LOH Toro-X-S / SL fining machine using a 15 μm pad made by 3M. The fining time is about 1 to 2 minutes. The lens was then washed with water and soap and coated with an abrasion-resistant coating by the process of the invention using a thin flexible wafer and the inflatable membrane apparatus as described in connection with the figures.

[0131] 5 drops of the liquid coating composition (0.12 g in total) are deposited on the fined main face of the lens. The thin flexible wafer is carefully placed on the liquid coating composition drops.

[0132] The resulting assembly is then placed in front of the inflatable membrane of the air accumulator and air is introduced up to a pressure of 84 kPa (12 Psi) so that the liquid coating composition ...

example 2

[0137] Example 1 is reproduced except using a liquid coating composition of refractive index nD25=1.532

[0138] This liquid composition has the following formulation, in weight %:

EPON 228 (bisphenol A epoxy resin)60GE 21 (1,4-butanediol diglycidyl ether)40IRGACURE 552 (photoinitiator)  4 phrITX (sensitizer)0.2 phr

example 3

[0141] A PC SF lens was generated by V-95 and fined with 15 μm pad to −2.00 power lens (back curve=5.0 base) without polishing. The lens was then washed with soap and water and the same coating solution as in comparative example 2 is applied as in Example 1.

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Abstract

The invention concerns a process for making a coated optical lens blank free of visible fining lines which comprises: (i) providing an optical article having at least one fined but unpolished geometrically defined main face; (ii) providing a mold part having an internal and external surface; (iii) depositing on said main face of said optical article or on the internal surface of the mold part a requisite amount of a liquid curable coating composition; (iv) moving relatively to each other the optical article and the mold part to either bring the coating composition into contact with the main face of the optical article or into contact with the internal face of the mold part; (v) applying pressure to the mold part to spread the liquid curable coating composition on said main face and form a uniform liquid coating composition layer onto the main face; (vi) curing the liquid coating composition layer; (vii) withdrawing the mold part; and (viii) recovering the free of visible fining lines coated optical article.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to a process for making a coated optical article, in particular an ophthalmic lens, a lens blank or a lens mold, free of visible fining lines, and in particular for directly forming a functional coating, such as an anti-abrasion hard coating, onto a fined but unpolished main face of an optical article, whereby no fining lines are visible when the coated lens blank is illuminated with an arc lamp. This process may be designated as “press coating process”. [0002] The main faces of an ophthalmic lens blank, such as a lens blank made of a transparent plastic material, are classically subjected to a surface mechanical treatment. [0003] This mechanical treatment comprises a group of operations leading to the production of a lens blank whose main faces are perfectly polished and have the desired curvatures (optical powers). [0004] The mechanical treatment typically comprises three successive steps grinding, fine grinding (als...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B29D11/00
CPCB29C66/81455B29C66/545B29L2011/0016B29D11/0073B29K2995/007B29C66/73161B29K2995/0072B29C66/71B29C43/021B29C2035/0827B29C2043/3649B29C2043/3652B29C2043/3655B29K2995/0026B29K2069/00B29K2033/12
Inventor JIANG, PEIQIWEBER, STEVENADILEH, FADI O.
Owner ESSILOR INT CIE GEN DOPTIQUE
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