US4568982A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical scanning method and apparatus
Assignee: AT&T Labs Inc
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Filing: 1984-04-09
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Granted: 1986-02-04
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Expires: 2004-04-09
Abstract
Abstract Disclosed is a high resolution optical scanning method and apparatus. Light from a source, such as a laser, is focused onto a flat, rotating mirror. The reflected light is made incident upon a stationary elliptical mirror such that the real or virtual source is at one focus of the ellipse and the points on the line to be scanned are at the other focus along the lateral dimension of the mirror. A large useful angle of rotation is thereby achieved for each line scan.
Inventors
- 👤 David R. Follett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:38
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/113; H04N1/1135
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
97 words
An optical scanning apparatus comprising: a rotatably mounted first mirror having a flat reflecting surface and mounted so as to deflect light incident thereon in an essentially circular path as the mirror is rotated; and a stationary second mirror having an elliptical reflecting surface in at least two dimensions and positioned such that the point of reflection of light from the rotating mirror is effectively at one focus of the elliptical surface and the stationary mirror is adapted to reflect light in a line through the other focus of the ellipse as the first mirror is rotated.
Claim 2
Dependent Claim
97 words
An optical scanning apparatus comprising: a rotatably mounted first mirror having a flat reflecting surface and mounted so as to deflect light incident thereon in an essentially circular path as the mirror is rotated; and a stationary second mirror having an elliptical reflecting surface in at least two dimensions and positioned such that the point of reflection of light from the rotating mirror is effectively at one focus of the elliptical surface and the stationary mirror is adapted to reflect light in a line through the other focus of the ellipse as the first mirror is rotated.
Claim 3
Dependent Claim
29 words
The apparatus according to claim 1 wherein the stationary second mirror forms a portion of an elliptical cylinder adapted to reflect light in a line parallel to its axis.
Claim 4
Dependent Claim
12 words
The apparatus according to claim 1 further comprising a laser light source.
Claim 5
Dependent Claim
23 words
The apparatus according to claim 1 wherein the rotating mirror provides a complete line scan with a rotation of at least 60 degrees.
Claim 6
Dependent Claim
54 words
The apparatus according to claim 1 wherein the rotating mirror is positioned at a distance from the said one focus of the elliptical surface and a stationary third mirror is provided to reflect light from the rotating mirror so that the virtual source of light from the rotating mirror is at the said focus.
Claim 7
Dependent Claim
37 words
The apparatus according to claim 1 further comprising an object to be scanned comprising a rotatably mounted drum with a portion of its surface located at said other focus of the elliptical surface of the second mirror.
Claim 8
Dependent Claim
37 words
The apparatus according to claim 1 wherein the sweep velocity of the light beam varies no more than 10 percent over the length of the line scanned for a first mirror rotation no greater than 120 degrees.
Claim 9
Dependent Claim
141 words
An optical scanning apparatus comprising: a laser light source; a rotatably mounted first mirror having a flat reflecting surface at an angle with respect to light incident from said source so as to deflect the light in an essentially circular path as the mirror is rotated; a stationary second mirror for reflecting the light from the first mirror; a stationary third mirror in the shape of a portion of an elliptical cylinder for receiving the light from the second mirror and positioned so that the virtual source of light from the rotating mirror is at one focus of the elliptical surface of the third mirror; and an object to be scanned comprising a rotatably mounted drum with a portion of the surface coinciding with the other foci of the elliptical surface in a line parallel to the axis of the cylinder.
Claim 10
Dependent Claim
141 words
An optical scanning apparatus comprising: a laser light source; a rotatably mounted first mirror having a flat reflecting surface at an angle with respect to light incident from said source so as to deflect the light in an essentially circular path as the mirror is rotated; a stationary second mirror for reflecting the light from the first mirror; a stationary third mirror in the shape of a portion of an elliptical cylinder for receiving the light from the second mirror and positioned so that the virtual source of light from the rotating mirror is at one focus of the elliptical surface of the third mirror; and an object to be scanned comprising a rotatably mounted drum with a portion of the surface coinciding with the other foci of the elliptical surface in a line parallel to the axis of the cylinder.
Claim 11
Independent Claim
112 words
A method of optically scanning an object comprising the steps of: directing a light beam toward a rotatably mounted first mirror with a flat reflecting surface at an angle to the beam; rotating the mirror so as to reflect the beam in an essentially circular path; directing the reflected light to a second mirror having an elliptical reflecting surface in at least two dimensions and positioned so that the point of reflection from the rotating mirror is effectively at one focus of the elliptical surface; and positioning a line on the surface of the scanned object at the other focus of the elliptical surface along the third dimension of the second mirror.
Claim 12
Independent Claim
112 words
A method of optically scanning an object comprising the steps of: directing a light beam toward a rotatably mounted first mirror with a flat reflecting surface at an angle to the beam; rotating the mirror so as to reflect the beam in an essentially circular path; directing the reflected light to a second mirror having an elliptical reflecting surface in at least two dimensions and positioned so that the point of reflection from the rotating mirror is effectively at one focus of the elliptical surface; and positioning a line on the surface of the scanned object at the other focus of the elliptical surface along the third dimension of the second mirror.
Claim 13
Dependent Claim
44 words
The method according to claim 9 wherein the second mirror is in the form of a portion of an elliptical cylinder and the line on the surface is made coincident with the foci of the elliptical surface parallel to the axis of the cylinder.
Claim 14
Dependent Claim
34 words
The method according to claim 9 wherein the scanned object is a drum which is rotatably mounted so that successive lines on the surface can be positioned at the focus of the elliptical surface.
Claim 15
Dependent Claim
21 words
The method according to claim 9 wherein a line is scanned by rotating the first mirror by at least 60 degrees.
Claim 16
Dependent Claim
48 words
The method according to claim 9 wherein the beam from the first mirror is directed to a third mirror which reflects the beam to the second mirror so that the virtual source of the light from the first mirror is at the said focus of the elliptical surface.
Claim 17
Dependent Claim
33 words
The method according to claim 9 wherein the sweep velocity of the light beam varies no more than ten percent along the line scanned for a mirror rotation no greater than 120 degrees.
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) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |