US3746450A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for inspecting surface treated ophthalmic lenses
Assignee: American Optical Corp
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Filing: 1972-06-26
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Granted: 1973-07-17
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Expires: 1992-06-26
Abstract
Abstract Glass ophthalmic lenses which have been treated by a process of ion exchange provide increased impact resistance and durability. It is necessary that these lenses be inspected to ascertain that the desired penetration of the ion exchange process has occurred prior to dispensing the lenses to the public. This may now be accomplished by introducing into the hardened exterior layer light waves at essentially grazing refraction. Because the hardened outer layer is of compressively stressed nature, the resulting index of refraction is generally higher than that of the interior of the lens. These light waves which were introduced at essentially grazing refraction are confined to the compressively stressed layer and are guided along the surface in a surface wave mode. The surface wave mode energy may be refracted out of the surface layer to provide a positive output signal. If the hardened layer is not present, these rays will not be guided along the surface of the lens but rather will penetrate into the interior of the lens and will provide no output.
Inventors
- 👤 L Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:43
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G01N21/43; G01M; G01M11/00; G01M11/02
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
278 words
A method for inspecting an ophthalmic lens for the presence of an outer surface treated layer on a compoundly curved refractive suRface of the ophthalmic lens, the outer surface treated layer having a higher index of refraction than the interior of the ophthalmic lens, the method comprising the steps of: placing a launcher member formed of an optical material having a higher index of refraction than the outer surface treated layer in optical contact with the refractive surface and forming a first interface therebetween; directing a beam of light onto an entrance window on the launcher member; adjusting the direction of the beam of light both within and without the launcher member to cause rays in the beam of light to apProach the first interface at slightly less than the critical angle of total internal reflection as determined by the refractive indices of the optical material and the outer surface treated layer so that the rays are refracted at the first interface at nearly grazing refraction and are propagated along the surface as surface waveguide mode radiation only if the outer surface treated layer is present; placing a receiver member formed of an optical material having a higher index of refraction than the outer surface treated layer in optical contact with the refractive surface and forming a second interface therebetween; positioning the receiver member to be aligned with any surface waveguide mode radiation propagating along the surface, the radiation entering through the second interface and passing into the receiver member; and detecting the presence of any radiation entering from the receiver member, the presence thereof indicating that the outer surface treated layer is present on the ophthalmic lens.
Claim 2
Independent Claim
278 words
A method for inspecting an ophthalmic lens for the presence of an outer surface treated layer on a compoundly curved refractive suRface of the ophthalmic lens, the outer surface treated layer having a higher index of refraction than the interior of the ophthalmic lens, the method comprising the steps of: placing a launcher member formed of an optical material having a higher index of refraction than the outer surface treated layer in optical contact with the refractive surface and forming a first interface therebetween; directing a beam of light onto an entrance window on the launcher member; adjusting the direction of the beam of light both within and without the launcher member to cause rays in the beam of light to apProach the first interface at slightly less than the critical angle of total internal reflection as determined by the refractive indices of the optical material and the outer surface treated layer so that the rays are refracted at the first interface at nearly grazing refraction and are propagated along the surface as surface waveguide mode radiation only if the outer surface treated layer is present; placing a receiver member formed of an optical material having a higher index of refraction than the outer surface treated layer in optical contact with the refractive surface and forming a second interface therebetween; positioning the receiver member to be aligned with any surface waveguide mode radiation propagating along the surface, the radiation entering through the second interface and passing into the receiver member; and detecting the presence of any radiation entering from the receiver member, the presence thereof indicating that the outer surface treated layer is present on the ophthalmic lens.
Claim 3
Dependent Claim
59 words
The method according to claim 1, further including the steps of placing an amount of an optically clear intermediate fluid between the refractive surface and each of the launcher and receiver members sufficient to create good optical contact therebetween, the intermediate fluid having an index of refraction higher than the index of refraction of the outer surface treated layer.
Claim 4
Dependent Claim
32 words
The method according to claim 2, further including the step of preventing any light from passing from the launcher member to the receiver member other than through the outer surface treated layer.
Claim 5
Dependent Claim
27 words
The method according to claim 3, in which light is prevented from passing from the launcher member to the receiver member by interposing a light absorbing baffle.
Claim 6
Dependent Claim
42 words
The method according to claim 4, further including the step of forming the launcher member, the interposed light absorbing baffle, and the receiver member into an integral surface wave transducer unit having a common spherical surface thereon for contacting the refractive surface.
Claim 7
Dependent Claim
17 words
The method according to claim 1, wherein the method is performed on a concavely curved refractive surface.
Claim 8
Dependent Claim
21 words
The method according to claim 1, further including the step of forming the beam of light into a narrowly divergent beam.
Claim 9
Dependent Claim
287 words
Apparatus for inspecting an ophthalmic lens for the presence of an outer surface treated layer on a compoundly curved refractive surface of the ophthalmic lens, the outer surface treated layer having a higher index of refraction than the interior of the ophthalmic lens, the apparatus comprising: a launcher member formed of an optical material having a higher index of refraction than the outer surface treated layer for placing in optical contact with the refractive surface and forming a first interface therebetween; a light source for generating a beam of light which impinges on an entrance window on the launcher member; means for adjusting the direction of the beam of light both within and without the launcher member to cause rays in the beam of light to approach the first interface at slightly less than the critical angle of total internal reflection as determined by the refractive indices of the optical material and the outer surface treated layer so that the rays are refracted at the first interface at nearly grazing refraction and are propagated along the surface as surfaCe waveguide mode radiation only if the outer surface treated layer is present; a receiver member formed of an optical material having a higher index of refraction than the outer surface treated layer for placement in optical contact with the refractive surface and forming a second interface therebetween, the receiver member being aligned with any surface waveguide mode radiation propagating along the surface, the radiation entering through the second interface and passing into the receiver member; and means for detecting the presence of any radiation entering the receiver member through the second interface, the presence thereof indicating that the outer surface treated layer is present on the ophthalmic lens.
Claim 10
Dependent Claim
287 words
Apparatus for inspecting an ophthalmic lens for the presence of an outer surface treated layer on a compoundly curved refractive surface of the ophthalmic lens, the outer surface treated layer having a higher index of refraction than the interior of the ophthalmic lens, the apparatus comprising: a launcher member formed of an optical material having a higher index of refraction than the outer surface treated layer for placing in optical contact with the refractive surface and forming a first interface therebetween; a light source for generating a beam of light which impinges on an entrance window on the launcher member; means for adjusting the direction of the beam of light both within and without the launcher member to cause rays in the beam of light to approach the first interface at slightly less than the critical angle of total internal reflection as determined by the refractive indices of the optical material and the outer surface treated layer so that the rays are refracted at the first interface at nearly grazing refraction and are propagated along the surface as surfaCe waveguide mode radiation only if the outer surface treated layer is present; a receiver member formed of an optical material having a higher index of refraction than the outer surface treated layer for placement in optical contact with the refractive surface and forming a second interface therebetween, the receiver member being aligned with any surface waveguide mode radiation propagating along the surface, the radiation entering through the second interface and passing into the receiver member; and means for detecting the presence of any radiation entering the receiver member through the second interface, the presence thereof indicating that the outer surface treated layer is present on the ophthalmic lens.
Claim 11
Dependent Claim
51 words
The apparatus according to claim 8, in which the surfaces of the launcher and receiver members which are emplaced on the ophthalmic lens are convex spherical surfaces the radii of which are at least as short as the shortest local radius of curvature on the concave surface of the ophthalmic lens.
Claim 12
Dependent Claim
57 words
The apparatus according to claim 9, in which a film of an optically clear intermediate fluid is located between the refractive surface and each of the launcher and receiver members sufficient to create good optical contact therebetween, the intermediate fluid having an index of refraction higher than the index of refraction of the outer surface treated layer.
Claim 13
Dependent Claim
33 words
The apparatus according to claim 9, in which means are included for preventing any light from passing from the launcher member to the receiver member other than through the outer surface treated layer.
Claim 14
Dependent Claim
27 words
The apparatus according to claim 11, in which light is prevented from passing from the launcher member to the receiver member by an interposed light absorbing baffle.
Claim 15
Dependent Claim
52 words
The apparatus according to claim 12, in which the launcher member, the interposed light absorbing baffle, and the receiver member are joined together into an integral surface wave transducer, the contacting surfaces of the launcher member and receiver member portions of the surface wave transducer are formed as a common spherical surface.
Claim 16
Dependent Claim
28 words
The apparatus according to claim 13, in which the interposed light absorbing baffle also forms a portion of the common spherical surface with the launcher and receiver members.
Claim 17
Dependent Claim
48 words
The apparatus according to claim 14, in which the entrance window on the launcher and an exit window on the receiver are a pair of parallel end face windows formed on the surface wave transducer, for the passing of light into and out of the surface wave transducer.
Claim 18
Dependent Claim
30 words
The apparatus according to claim 15, in which the means for detecting includes a ground glass screen disposed essentially normal to the rays of light exiting from the receiver member.
Claim 19
Dependent Claim
22 words
The apparatus according to claim 8, in which means are included for forming the beam of light into a narrowly divergent beam.
Claim 20
Dependent Claim
22 words
The apparatus according to claim 8, wherein the outer surface treated layer is an outer compressively stressed layer on the ophthalmic lens.
Claim 21
Dependent Claim
20 words
The apparatus according to claim 18, wherein the outer compressively stressed layer is formed by a process of ion exchange.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |