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Patent EP0031633A2 successfully refreshed from Google Patents.
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EP0031633A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method of marking a lens of plastics material

Assignee: Hoya Lens Corp
•
Filing: 1980-04-25
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Granted: —
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Expires: 2000-04-25
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Abstract

Abstract Hydrophilic indicia are marked on an ophthalmic lens of plastics material by treating the lens surface with an agent which provides a marking on the lens surface which is visible only when moisture is applied to the lens surface, for instance when a person's breath is applied to the lens surface. Lenses so marked are readily identified and recognized when fogged but otherwise remain totally transparent with the optical properties of the lens itself being unaffected. The agent used is concentrated sulfuric acid at a concentration of 50% and, to reduce application times, up to 1 % of a sulfate, preferably silver sulfate.

Inventors

  • 👤 Niro Tarumi
  • 👤 Shigeo Komiya
  • 👤 Makoto Tsuchiya

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-23 23:37
CPC Classifications
B; B29; B29D; B29D11/00; B29D11/00865; B29D11/00894; B29D11/00903; G; G02; G02B; G02B1/00; G02B1/04; G02B1/041; G02C; G02C7/00; G02C7/02; G02C7/021; B29K; B29K2995/00; B29K2995/0037; B29K2995/0092

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 38 words
A method for marking indicia on the surface of a lens made of plastics material characterised in that a concentrated sulfuric acid solution is applied to the lens surface in a pattern such as to form said indicia.
Claim 2
Independent Claim 38 words
A method for marking indicia on the surface of a lens made of plastics material characterised in that a concentrated sulfuric acid solution is applied to the lens surface in a pattern such as to form said indicia.
Claim 3
Dependent Claim 23 words
A method according to Claim 1 wherein the concentration of the sulfuric acid solution is at least 50% by weight of sulfuric acid.
Claim 4
Dependent Claim 18 words
A method according to Claim 2 wherein the concentration of the sulfuric acid solution is at least 97%.
Claim 5
Dependent Claim 24 words
A method according to Claim 1,Claim 2 or Claim 3 wherein said sulfuric acid solution contains up to 1.0% by weight of a sulfate.
Claim 6
Dependent Claim 20 words
A method according to Claim 4 wherein said sulfuric acid solution contains up to 0.1% by weight of a sulfate.
Claim 7
Dependent Claim 15 words
A method according to Claim 4 or Claim 5 wherein said sulfate is silver sulfate.
Claim 8
Independent Claim 24 words
A method according to any of the preceding claims wherein the method is carried out at a temperature of at least 60o C .
Claim 9
Independent Claim 37 words
A method according to any one of the preceding claims wherein the sulfuric acid solution is left in contact with the surface for a time sufficient to achieve the marking and then is rinsed off with water.
Claim 10
Independent Claim 22 words
A method according to any one of the preceding claims wherein the plastics material of the lens is polycarbonate or polydiethyleneglycol bisallylcarbonate.

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