Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
137 words
A method of making a master replicating tool having a predetermined aspherical negative profile from which a plurality of substantially identical lenses or mirrors each with a positive profile of the negative aspherical profile can be made, comprising working the surface of a blank of a hard, non-deformable siliceous material to form the profile, characterised in that the hard, non-deformable siliceous material is machined with a cutting or grinding tool to produce substantially the predetermined profile in a one-stage operation and the siliceous surface is coated with a layer of nickel or a nickel based alloy after which the nickel surface is machined with a cutting tool and polished to an optical finish to produce the predetermined profile and a protective layer of an inert scratch-resistant material is applied to the profiled nickel surface by vacuum deposition.
Claim 2
Independent Claim
137 words
A method of making a master replicating tool having a predetermined aspherical negative profile from which a plurality of substantially identical lenses or mirrors each with a positive profile of the negative aspherical profile can be made, comprising working the surface of a blank of a hard, non-deformable siliceous material to form the profile, characterised in that the hard, non-deformable siliceous material is machined with a cutting or grinding tool to produce substantially the predetermined profile in a one-stage operation and the siliceous surface is coated with a layer of nickel or a nickel based alloy after which the nickel surface is machined with a cutting tool and polished to an optical finish to produce the predetermined profile and a protective layer of an inert scratch-resistant material is applied to the profiled nickel surface by vacuum deposition.
Claim 3
Dependent Claim
59 words
A method according to Claim 1 characterised in that the hard, non-deformable, siliceous material comprises a ceramic or a glass having a low coefficient of thermal expansion over a temperature range of +150°C to -50°C said material being machined with a single point machine cutting tool without producing fracture planes greater than 20 µm deep on the machined surface.
Claim 4
Dependent Claim
26 words
A method according to Claim 1 or Claim 2 characterised in that the hard, non-deformable siliceous material is machined to within 20µm of the predetermined profile.
Claim 5
Independent Claim
36 words
A method according to any one of Claims 1 to 3 characterised in that the layer of nickel or nickel based alloy deposited on the machined siliceous surface is between 30 to 100µm thick before polishing.
Claim 6
Independent Claim
39 words
A method according to any one of Claims 1 to 4 characterised in that the nickel or nickel based alloy is deposited on the surface of the material by electro chemical deposition or by a vaporised metal deposition technique.
Claim 7
Independent Claim
55 words
A method according to any one of Claims 1 to 5 in which the surface of the optically polished nickel layer is protected by a layer of inert, scratch-resistant material comprising a layer of vapour-deposited vitreous carbon of not less than 500 m- 10 (A) thick and not greater than 5000 m- 11 (A) thick.
Claim 8
Independent Claim
68 words
A method according to any one of Claims 1 to 6 characterised in that the layer of nickel or nickel based alloy deposited is between 30 to 100µm thick which is then machined by a diamond point machining tool to within 5 µm of the predetermined profile and polished to within 2µm or less of the predetermined profile prior to coating with the layer of insert, scratch-resistant material.
Claim 9
Dependent Claim
18 words
A master replicating tool when made by the method according to any one of Claims 1 to 7.