US4984857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Linearization of scan velocity of resonant vibrating-mirror beam deflectors
Assignee: Iowa State University Research Foundation Inc
•
Filing: 1989-01-17
•
Granted: 1991-01-15
•
Expires: 2009-01-17
Abstract
Abstract A means and method for producing linerization of scan velocity of resonant vibrating-mirror beam deflectors in laser scanning system including presenting an elliptical convex surface to the scanning beam to reflect the scanning beam to the focal plane of the scanning line. The elliptical surface is shaped to produce linear velocity of the reflective scanning beam at the focal plane. Maximization of linerization is accomplished by considering sets of criteria for different scanning applications.
Inventors
- 👤 Edward S. Yeung
- 👤 Shun-Le Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:20
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/0025; G02B27/0031; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
151 words
A means for linearization of scan velocity of a resonant vibrating-mirror beam deflector where an energy beam is directed along a beam path to a deflector means including a resonating mirror having a rotational axis for deflecting a first reflected portion of the beam in a plane normal to the rotational axis for scanning the beam along a scan line, the improvement comprising: a beam path altering means positioned in the beam path following the resonating mirror for linearizing scan velocity in a focal plane, the altering means comprising an elliptical surface having a major and minor axis and being disposed in such a manner that the minor axis of the elliptical surface is coaxial with a line in normal alignment to the mirror, the elliptical surface being shaped to maximize the linearity between positions of a second reflected portion of the beam along the scan line in relationship to time.
Claim 2
Dependent Claim
151 words
A means for linearization of scan velocity of a resonant vibrating-mirror beam deflector where an energy beam is directed along a beam path to a deflector means including a resonating mirror having a rotational axis for deflecting a first reflected portion of the beam in a plane normal to the rotational axis for scanning the beam along a scan line, the improvement comprising: a beam path altering means positioned in the beam path following the resonating mirror for linearizing scan velocity in a focal plane, the altering means comprising an elliptical surface having a major and minor axis and being disposed in such a manner that the minor axis of the elliptical surface is coaxial with a line in normal alignment to the mirror, the elliptical surface being shaped to maximize the linearity between positions of a second reflected portion of the beam along the scan line in relationship to time.
Claim 3
Dependent Claim
58 words
The means for linearization of claim 1, wherein the shape of the elliptical surface is based on the following criteria: position of the altering means with respect to the mirror, position of the elliptical surface with respect to the mirror, distance between the focal plane and the altering means, the distance between the mirror and the altering means.
Claim 4
Dependent Claim
35 words
The means for linearization of claim 2, wherein the parameter defining the elliptical surface are determined by considering further the fraction of the elliptical surface involved in reflecting the first reflected portion of the beam.
Claim 5
Dependent Claim
36 words
The means for linerization of claim 2, wherein the shape of the elliptical surface is determined by considering the further factors of the ratio of the major axis to the minor axis of the elliptical surface.
Claim 6
Dependent Claim
29 words
The means for linearization of claim 2, wherein the shape of the elliptical surface is determined by further taking in consideration the maximum deflection angle required of the beam.
Claim 7
Dependent Claim
26 words
The means for linearization of claim 1, wherein the altering means comprises a member which is elliptical in cross-section and having an elliptical convex reflecting surface.
Claim 8
Dependent Claim
30 words
The means for linearization of claim 1, wherein the elliptical surface of the altering means is defined by a major axis greater in length than the scanning range across it.
Claim 9
Dependent Claim
32 words
The means for linearization of claim 1, wherein the minor axis of the elliptical surface is much smaller than the distance between the mirror and the major axis of the altering means.
Claim 10
Dependent Claim
39 words
The means for linearization of claim 1, wherein the distance between the mirror and the major axis of the elliptical surface is much smaller than the distance between the focal plane and the major axis of the elliptical surface.
Claim 11
Dependent Claim
143 words
The means for linearization of claim 1, wherein A.sub.f 32 A.sub.i 30 2A.sub.x where A f is the angle between the second reflected portion of the beam and a line normal to the major axis of the elliptical surface at a point of incidence of the first reflected portion of the beam onto the elliptical surface, A i is the angle between the first reflected portion of the beam and a line parallel to the minor axis of the elliptical surface at a point of reflection of the second reflected portion of the beam on the elliptical surface the point of incidence and reflection constituting the same point on the elliptical surface; and A x is the angle between the line parallel to the minor axis and the line normal to the elliptical surface at the point of incidence on the elliptical surface.
Claim 12
Dependent Claim
15 words
The means for linearization of claim 10, wherein tan A f is a linear function.
Claim 13
Dependent Claim
95 words
The means of linearization of claim 11, wherein the following equation is utilized to define the elliptical surface for linearization of scan velocity tan A.sub.x =(b.sup.2 /a.sup.2 x(t))/(b.sup.2 31 b.sup.2 /a.sup.2 x.sup.2 (t).sup.1/2) where a equals, the length of the major axis and b equals the length of the minor axis of the elliptical surface of the altering means, and X(t) is the projected distance of the point of reflection of the second reflected portion of the beam onto an x-axis coincident with the major axis of the elliptical surface as a function of time.
Claim 14
Dependent Claim
16 words
The means for linearization of claim 12, wherein tan A.sub.f =(tan A.sub.i +tan 2A.sub.x)/(1-tanA.sub.i tan 2A.sub.x).
Claim 15
Dependent Claim
28 words
The means for linearization of claim 1, further comprising an fθ lens utilized to recollimate the second reflected portion of the beam after reflection from the elliptical surface.
Claim 16
Independent Claim
94 words
A method of linearization of scan velocity of a resonant vibrating-mirror beam deflector comprising: positioning a beam path altering means having an elliptical surface at least along a scanning range into the beam path of a scanning beam, so that the minor axis of the elliptical surface is coaxial with the scanning beam at the midpoint of the scanning range; and forming the elliptical surface so as to maximize the linearity between positions of a reflected portion of the scanning beam reflected from said elliptical surface along a focal plane in relationship to time.
Claim 17
Independent Claim
94 words
A method of linearization of scan velocity of a resonant vibrating-mirror beam deflector comprising: positioning a beam path altering means having an elliptical surface at least along a scanning range into the beam path of a scanning beam, so that the minor axis of the elliptical surface is coaxial with the scanning beam at the midpoint of the scanning range; and forming the elliptical surface so as to maximize the linearity between positions of a reflected portion of the scanning beam reflected from said elliptical surface along a focal plane in relationship to time.
Claim 18
Dependent Claim
54 words
The method of claim 15, wherein the elliptical surface is formed by considering the following criteria: position of the altering means with respect to the mirror, position of the elliptical surface with respect to the mirror, distance between the focal plane and the altering means, the distance between the mirror and the altering means.
Claim 19
Dependent Claim
127 words
The method of claim 16, wherein A.sub.f =A.sub.i +2A.sub.x where A f is the angle between the reflected portion of the scanning beam and a line normal to the major axis of the elliptical surface at a point of incidence of the scanning beam onto the elliptical surface, A i is the angle between the scanning beam and a line parallel to the minor axis of the elliptical surface at a point of reflection on the elliptical surface, the point of incidence and reflection constituting the same point on the elliptical surface; and A x is the angle between the line parallel to the minor axis and the line normal to the elliptical surface at the point of incidence of the scanning beam on the elliptical surface.
Claim 20
Dependent Claim
14 words
The method of claim 17, wherein the tan A f is a linear function.
Claim 21
Dependent Claim
39 words
The method of claim 16, further comprising the step of positioning an fθ lens with respect to the reflected portion of the scanning beam to recollimate the reflected portion of the scanning beam after reflection from the elliptical surface.
Claim 22
Independent Claim
302 words
A method for producing a beam path altering means for linearization of scan velocity of a resonant vibrating-mirror beam deflector, a scanning beam including a first reflected beam portion, reflected from the beam deflector, incident onto the beam path altering means and a second reflected beam portion reflected from the beam path altering means, comprising: specifying required parameters relating to a reflective elliptical surface to maximize linearization of scan velocity of a scanning beam along a focal plane, the parameters including but not limited to major and minor axes dimensions defining the elliptical surface, distance of the elliptical surface from the beam deflector, distance from the major axis of the elliptical surface to the focal plane for the scanning beam, by linearizing the function tan A f in the equation A.sub.f =A.sub.i +2A.sub.x where A f is the angle between the second reflected beam portion of the scanning beam and a line normal to the major axis of the elliptical surface at a point of incidence of the first reflected beam portion of the scanning beam onto the elliptical surface, A i is the angle between the first reflected beam portion of the scanning beam and a line parallel to the minor axis of the elliptical surface at a point of reflection of the second reflected beam portion of the scanning beam on the elliptical surface, the point of incidence and reflection constituting the same point on the elliptical surface; and A x is the angle between the line parallel to the minor axis and the line normal to the elliptical surface at the point of incidence; selecting a cylinder of appropriate diameter and slicing the cylinder at an appropriate angle to produce generally the desired elliptical surface; and machining the elliptical surface to match the desired shape of the elliptical surface.
Claim 23
Independent Claim
302 words
A method for producing a beam path altering means for linearization of scan velocity of a resonant vibrating-mirror beam deflector, a scanning beam including a first reflected beam portion, reflected from the beam deflector, incident onto the beam path altering means and a second reflected beam portion reflected from the beam path altering means, comprising: specifying required parameters relating to a reflective elliptical surface to maximize linearization of scan velocity of a scanning beam along a focal plane, the parameters including but not limited to major and minor axes dimensions defining the elliptical surface, distance of the elliptical surface from the beam deflector, distance from the major axis of the elliptical surface to the focal plane for the scanning beam, by linearizing the function tan A f in the equation A.sub.f =A.sub.i +2A.sub.x where A f is the angle between the second reflected beam portion of the scanning beam and a line normal to the major axis of the elliptical surface at a point of incidence of the first reflected beam portion of the scanning beam onto the elliptical surface, A i is the angle between the first reflected beam portion of the scanning beam and a line parallel to the minor axis of the elliptical surface at a point of reflection of the second reflected beam portion of the scanning beam on the elliptical surface, the point of incidence and reflection constituting the same point on the elliptical surface; and A x is the angle between the line parallel to the minor axis and the line normal to the elliptical surface at the point of incidence; selecting a cylinder of appropriate diameter and slicing the cylinder at an appropriate angle to produce generally the desired elliptical surface; and machining the elliptical surface to match the desired shape of the elliptical surface.
References Cited (Backward Citations)
US3238470A
Cited
US4084182A
Cited
US3961838A
Cited
JPS5257823A
Cited
US4037231A
Cited
US4155620A
Cited
US4264119A
Cited
US4213146A
Cited
US4368488A
Cited
JPS57606A
Cited
JPS5872915A
Cited
US4638370A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-14 | 1994-07-16 | 1995-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-14 | 1998-07-16 | 1999-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-14 | 2002-07-16 | 2003-01-15 | $7700.00 | Window Closed / Lapsed |