US3623809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical system with polarizing filters for line follower head
Assignee: Hancock and Co Engineers Ltd
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Filing: 1969-12-23
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Granted: 1971-11-30
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Expires: 1989-12-23
Abstract
Abstract An optical system for a line follower head which avoids geometric errors and reflections, in which the beam from a light source is passed through a first polarizing filter to polarize the beam in one plane, then through a semireflecting surface to beam deflecting means to cause the beam to scan the outline carried on a substrate, the diffused and reflected light from the substrate being passed back along the same axis to the semireflecting surface and the light reflected therefrom being passed through a second polarizing filter set in quadrature with first polarizing filter to a photosensitive element.
Inventors
- 👤 Kenneth Victor Diprose
- 👤 Arthur Stuart Forbes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:35
CPC Classifications
G; G06; G06K; G06K11/00; G06K11/02; G02; G02B; G02B27/00; G02B27/28; G02B27/283
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
164 words
An optical system for a line follower head comprising a light source to project a beam of light along an axis to a substrate bearing an outline to be followed, a first polarizing filter in the path of the beam to polarize the beam in one plane, a semireflecting surface set at an oblique angle to the beam axis through which the polarized beam is passed, optical means to focus the beam to a point at the surface of the substrate, beam deflecting means to cause the beam to cross and recross the outline continuously to generate line-crossing signals, light diffused and reflected from the substrate and the outline passing back along the axis through the deflecting means and the optical means to the semireflecting surface, a second polarizing filter set in quadrature with the first polarizing filter through which light reflected by the semireflecting surface is passed, and a photosensitive element to which the light passing through the second polarizing filter is directed.
Claim 2
Dependent Claim
164 words
An optical system for a line follower head comprising a light source to project a beam of light along an axis to a substrate bearing an outline to be followed, a first polarizing filter in the path of the beam to polarize the beam in one plane, a semireflecting surface set at an oblique angle to the beam axis through which the polarized beam is passed, optical means to focus the beam to a point at the surface of the substrate, beam deflecting means to cause the beam to cross and recross the outline continuously to generate line-crossing signals, light diffused and reflected from the substrate and the outline passing back along the axis through the deflecting means and the optical means to the semireflecting surface, a second polarizing filter set in quadrature with the first polarizing filter through which light reflected by the semireflecting surface is passed, and a photosensitive element to which the light passing through the second polarizing filter is directed.
Claim 3
Dependent Claim
23 words
A system as claimed in claim 1 in which the first and second polarizing filters are in the form of a single prism.
Claim 4
Dependent Claim
49 words
A system as claimed in claim 2 in which the prism is a Nicol prism which is modified by forming a flat surface at such an angle that the extraordinary ray in the returning beam may pass out of the prism through the said surface to the photosensitive element.
Claim 5
Dependent Claim
17 words
A system as claimed in claim 2 in which the semireflecting surface is incorporated in the prism.
Claim 6
Dependent Claim
49 words
A system as claimed in claim 4 in which the prism is a Nicol prism which is modified by forming a flat surface at such an angle that the extraordinary ray in the returning beam may pass out of the prism through the said surface to the photosensitive element.
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) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |