US3641885A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic drafting using projected ring of light
Assignee: Cal Comp Inc
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Filing: 1968-03-29
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Granted: 1972-02-15
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Expires: 1988-03-29
Abstract
Abstract The disclosure concerns a photoexposure device used in automatic drafting and characterized as forming a movable ring of light at the photosensitive drafting surface, and wherein said ring may be formed by a central mask at the optical axis and an outer mask spaced therefrom to form an aperture ring, the central mask sized in relation to the aperture to substantially eliminate bleeding of light at the ring of light on the drafting surface and toward the edge of the ring, during line drawing.
Inventors
- 👤 Armin J Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:42
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/22; G06K15/225
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
184 words
In a drafting machine, the combination comprising: a head adapted to overlie a photosensitive surface, said head being moved relative to and generally parallel to said surface, a source of light at the head, and means on the head directing light from said source and forming a ring of light at said surface during said relative movement of the head and surface, the ring characterized in that the illumination intensity within the ring substantially exceeds the illumination intensity inside a circular zone formed inwardly of the ring and at the optical axis defined by the ring, said means including a central mask at said axis and an outer mask spaced therefrom to define a ring-shaped aperture, said central mask sized in relation to said aperture to substantially eliminate bleeding of light at said surface toward the edge of the ring during said relative movement, said ring of light having an inner boundary defined by an inner circumference and an outer boundary defined by an outer circumference, the radial distance between said inner and outer circumferences being about one-fourth the radius of the outer circumference.
Claim 2
Dependent Claim
184 words
In a drafting machine, the combination comprising: a head adapted to overlie a photosensitive surface, said head being moved relative to and generally parallel to said surface, a source of light at the head, and means on the head directing light from said source and forming a ring of light at said surface during said relative movement of the head and surface, the ring characterized in that the illumination intensity within the ring substantially exceeds the illumination intensity inside a circular zone formed inwardly of the ring and at the optical axis defined by the ring, said means including a central mask at said axis and an outer mask spaced therefrom to define a ring-shaped aperture, said central mask sized in relation to said aperture to substantially eliminate bleeding of light at said surface toward the edge of the ring during said relative movement, said ring of light having an inner boundary defined by an inner circumference and an outer boundary defined by an outer circumference, the radial distance between said inner and outer circumferences being about one-fourth the radius of the outer circumference.
Claim 3
Dependent Claim
57 words
The combination of claim 1 including structure defining a series of ring shaped apertures selectively movable into the path of light from said source, said apertures having different overall sizes, said structure including, for each ring-shaped aperture, a central circular light mask and an outer light mask having an inner edge concentrically spaced from said central mask.
Claim 4
Dependent Claim
19 words
The combination of claim 2 including a rotary disc mounting said inner and outer masks at circularly spaced locations.
Claim 5
Dependent Claim
35 words
The combinatiOn of claim 1 wherein said source comprises an electric arc producing a bright spot of light transmitted along an optical axis, said central mask located to mask out said bright spot of light.
Claim 6
Dependent Claim
49 words
The combination of claim 1 wherein said last named means includes, in the light path between said source and said mask, condenser lens means for imaging said source, a light modulator and relay lens means; and, in the light path beyond said mask, a shutter and objective lens means.
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) | 1975-02-14 | 1975-08-16 | 1976-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-14 | 1979-08-16 | 1980-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-14 | 1983-08-16 | 1984-02-15 | $7700.00 | Window Closed / Lapsed |