US3756073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-contact tonometer
Assignee: CAMBRIDGE INSTRUMENTS Inc A CORP OF
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Filing: 1971-11-26
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Granted: 1973-09-04
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Expires: 1991-11-26
Abstract
Abstract An alignment system for a non-contact tonometer in which the pneumatic and corneal monitoring systems are aligned relative to the cornea such that a target image reflected from the cornea is superimposed on an aiming reticle and on a photocell. When thus aligned, and only then, the apparatus is electrically armed permitting it to discharge its fluid pulse.
Inventors
- 👤 R Lavallee
- 👤 B Grolman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:39
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/16; A61B3/165
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
246 words
A non-contact tonometer having a pneumatic system in which a fluid pulse is directed along a pneumatic axis and at a patient''s corneal surface, and a monitoring system in which the effect of said pulse on said surface is determined, said pneumatic system and Said monitoring system each including a control means, said tonometer being characterized by an alignment system disposed relative to an alignment axis coincident with said pneumatic axis, said alignment system including: an objective lens and an observation means disposed along said alignment axis, projection means to project a visible target image through said objective lens along said alignment axis toward the focal plane thereof and toward said corneal surface, said target image being reflected by said corneal surface along said alignment axis to form a visible reflected image at said observation means, a source of invisible alignment radiation and means to project an image of the source along said alignment axis toward said corneal surface, said source image being reflected by said corneal surface along said alignment axis toward said observation means, a beam divider disposed along said alignment axis between said objective and said observation means to direct the source image to a conjugate image plane, and a detector sensitive to said invisible alignment radiation at said conjugate image plane, said detector operatively connected to the control means of said pneumatic system and responsive to a conjugate reflected source image coincident thereon to actuate the control means of said pneumatic system.
Claim 2
Dependent Claim
246 words
A non-contact tonometer having a pneumatic system in which a fluid pulse is directed along a pneumatic axis and at a patient''s corneal surface, and a monitoring system in which the effect of said pulse on said surface is determined, said pneumatic system and Said monitoring system each including a control means, said tonometer being characterized by an alignment system disposed relative to an alignment axis coincident with said pneumatic axis, said alignment system including: an objective lens and an observation means disposed along said alignment axis, projection means to project a visible target image through said objective lens along said alignment axis toward the focal plane thereof and toward said corneal surface, said target image being reflected by said corneal surface along said alignment axis to form a visible reflected image at said observation means, a source of invisible alignment radiation and means to project an image of the source along said alignment axis toward said corneal surface, said source image being reflected by said corneal surface along said alignment axis toward said observation means, a beam divider disposed along said alignment axis between said objective and said observation means to direct the source image to a conjugate image plane, and a detector sensitive to said invisible alignment radiation at said conjugate image plane, said detector operatively connected to the control means of said pneumatic system and responsive to a conjugate reflected source image coincident thereon to actuate the control means of said pneumatic system.
Claim 3
Dependent Claim
55 words
A non-contact tonometer as defined in claim 1, said projection means including a visible light source, a target, and a beam deflector disposed along a projection axis, said projection axis joining said alignment axis at said beam deflector, said visible light source and said target effective to project said target image along said projection axis.
Claim 4
Dependent Claim
44 words
A non-contact tonometer as defined in claim 2, said projection means further including a battery of dioptric lenses selectively positionable along said projection axis to accommodate for refractive error in the eye of a patient enabling the patient to better fixate said target image.
Claim 5
Dependent Claim
41 words
A non-contact tonometer as defined in claim 2, said invisible alignment radiation being about 900nm and said detector is insensitive to visible light and sensitive to light having a wavelength of about 900nm to provide non-interfering visual and invisible alignment systems.
References Cited (Backward Citations)
US2352179A
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US3552857A
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US3471237A
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US3603688A
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US3585849A
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US3538754A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |