US4852956A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hologan scanner system
Assignee: ECRM Inc
•
Filing: 1987-11-23
•
Granted: 1989-08-01
•
Expires: 2007-11-23
Abstract
Abstract A hologon scanning system which generates an essentially bow-free scan line or lines across a surface using a planar, and preferably a holographic, grating disposed in a holding assembly which is rotated about an axis. The surface of the grating is at a constant angle of incidence with respect to a collimated beam of laser light propagating along the axis of rotation. The grating period for the wavelength of the laser beam and for the coordinate system associated with the rotating grating provides a diffraction angle from the grating which is constant with rotation angle; the diffracted beam being perpendicular to the rotation axis. An essentially bow-free, straight scan line is obtained across the receptor surface which may be a flat image plane or a cylindrical image plane having its axis along the axis of rotation of the grating. The beam scan angle across the receptor surface is equal to the angle of rotation of the grating, rather than being related to the angle of rotation by a factor approximately equal to the ratio of wavelength of the laser light to the grating period.
Inventors
- 👤 Charles J. Kramer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:16
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1285
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
222 words
A hologon scanner system which comprises a planar light transmissive member having a difference grating formed thereon, means providing a beam of light incident upon an area of said member with an angle of incidence θ i , which is essentially equal to the diffraction angle θ d , at every point across the entire area, means for rotating said member about an axis with said grating inclined at a predetermined angle to said axis so that a beam of light propagating with a principal direction component in the direction of said axis is diffracted by said grating to produce a diffracted beam transverse to said axis which scans an essentially bow free line across an image surface over a scan angle θ S =θ R , where θ R is the angle of rotation of said grating, said predetermined angle being such that the angle of incidence of said beam to said grating θ i and the diffraction angle θ d of said diffracted beam exciting said grating are essentially equal and remain constant over all angles of rotation θ R ; and sin θ=λ/2D where θ is approximately equal to θ i which is essentially equal to θ d for all values of θ R , and where λ is the wavelength of light and D is the grating period.
Claim 2
Dependent Claim
222 words
A hologon scanner system which comprises a planar light transmissive member having a difference grating formed thereon, means providing a beam of light incident upon an area of said member with an angle of incidence θ i , which is essentially equal to the diffraction angle θ d , at every point across the entire area, means for rotating said member about an axis with said grating inclined at a predetermined angle to said axis so that a beam of light propagating with a principal direction component in the direction of said axis is diffracted by said grating to produce a diffracted beam transverse to said axis which scans an essentially bow free line across an image surface over a scan angle θ S =θ R , where θ R is the angle of rotation of said grating, said predetermined angle being such that the angle of incidence of said beam to said grating θ i and the diffraction angle θ d of said diffracted beam exciting said grating are essentially equal and remain constant over all angles of rotation θ R ; and sin θ=λ/2D where θ is approximately equal to θ i which is essentially equal to θ d for all values of θ R , and where λ is the wavelength of light and D is the grating period.
Claim 3
Dependent Claim
13 words
The system according to claim 1 wherein said grating is a holographic grating.
Claim 4
Dependent Claim
56 words
The system according to claim 1 further comprising means for deflecting said beam propagating along said axis with respect to said grating to provide an angle other than said angle of incidence and said diffraction angle the sum of said diffracting angle and said predetermined angle defining the angle between said diffracted beam and said axis.
Claim 5
Dependent Claim
12 words
The system according to claim 3 wherein said deflecting means a prism.
Claim 6
Dependent Claim
13 words
The system according to claim 3 wherein said deflecting means is a grating.
Claim 7
Dependent Claim
20 words
The system according to claim 1 wherein said planar member is disposed so that said axis of rotation passes therethrough.
Claim 8
Dependent Claim
22 words
The system according to claim 6 wherein said planar member is rectilinear in shape and said axis passes through the middle thereof.
Claim 9
Dependent Claim
8 words
The system according to claim 1 wherein λ/D=1.4142.
Claim 10
Dependent Claim
44 words
The system according to claim 1 wherein said rotating means comprises a holder having an axis centrally thereof, a motor for rotating said holder, the axis of said holder being said rotation axis, and said member being mounted in said holder and rotatable therewith.
Claim 11
Dependent Claim
37 words
The system according to claim 9 wherein a plurality of said members each having a planar diffraction grating are mounted in said holder spaced radially from said axis and offset from each other circumferentially about said axis.
Claim 12
Dependent Claim
43 words
The system according to claim 10 wherein said plurality of members comprise at least one pair of said members which are disposed 180° from each other, the predetermined angles between said gratings and said axis being essentially equal and opposite to each other.
Claim 13
Dependent Claim
23 words
The system according to claim 10 wherein said beam intercepts each of said gratings as it rotates around said axis through said beam.
Claim 14
Dependent Claim
16 words
The system according to claim 12 wherein said grating members are symmetrically disposed about said axis.
Claim 15
Dependent Claim
80 words
The system according to claim 12 wherein said rotating means comprises a holder having an entrance for said beam at one end thereof and exit windows for the diffracted beam perpendicular to said axis in the wall of said holder and opposite to said grating members, said holder having a base, one end of each of said members being mounted on said base, disposed tilted with respect to said axis, and a motor for rotating said holder about said axis.
Claim 16
Dependent Claim
16 words
The system according to claim 1 wherein said member is mounted displaced radially from said axis.
Claim 17
Dependent Claim
59 words
The system according to claim 1 further comprising means for adjusting the tilt of said grating member with respect to said axis thereby adjusting said predetermined angle to compensate for cross scan errors due to variation in grating period, wedge errors in said member, and inclination of said axis with respect to the coordinate system associated with said grating.
Claim 18
Dependent Claim
73 words
The system according to claim 1 wherein said rotating means comprises a holder for said grating having a support surface and a side surface, means for pivotally mounting one end of said grating member on one of said surfaces, and means for movably supporting the opposite end of said grating on the other of said surfaces as so as to pivot said member and adjust the tilt thereof thereby adjusting said predetermined angle.
Claim 19
Dependent Claim
48 words
The system according to claim 17 wherein a plurality of said grating members are supported by said holder each displaced radially and from said axis and circumferentially from each other about said axis, separate ones of said pivotally and movably supporting means for each of said grating members.
Claim 20
Dependent Claim
33 words
The system according to claim 1 further comprising a preobjective focusing lens between said grating member and said image plane for focusing said diffracted beam, to a spot which scans across said line.
Claim 21
Dependent Claim
60 words
The system according to claim 19 further comprising a holder for said grating having an opening along said axis for entrance of said beam of light propagating in the direction of said axis, and an opening for exit of said diffracted beam perpendicular to said axis, said focusing lens being mounted in said exit opening and rotates with said grating.
Claim 22
Dependent Claim
49 words
The system according to claim 1 further comprising means providing a cylindrical surface around said axis of rotation which provides said image surface on which said line is scanned over a scan angle θ s equal to the angle of rotation θ R of said grating about said axis.
Claim 23
Dependent Claim
25 words
The system according to claim 21 further comprising a pre-objective focusing lens of sufficient focal length to focus said diffracted beam at said image plane.
Claim 24
Dependent Claim
48 words
The system according to claim 21 wherein a drum provides said cylindrical surface having an axis collinear with said rotating axis, an assembly including said grating member rotating in said drum, and means for translating said assembly along said axis to scan successive lines across said cylindrical surface.
Claim 25
Dependent Claim
27 words
The system according to claim 21 further comprising laser means providing said beam with a polarization selected from the group consisting of circular polarization and random polarization.
Claim 26
Dependent Claim
26 words
The apparatus according to claim 1 wherein said grating forms a holographic optical lens which focuses said diffracted beam into a spot which scans said line.
Claim 27
Dependent Claim
47 words
The system according to claim 1 wherein θ i =θ d and the grating is tilted with respect to a perpendicular to said axis sufficiently such that the light reflected from said grating along the path of said beam of light which is diffracted by said grating.
Claim 28
Dependent Claim
17 words
The system according to claim 26 wherein said image surface is cylindrical and collinear with said axis.
Claim 29
Dependent Claim
92 words
The system according to claim 26 wherein said grating is tilted from said axis by a tilt angle, θ T , such that said diffracted beam differs in direction from a direction 90° to said axis by said tilt angle θ T , θ i and θ d and any angle which the incident beam upon said grating makes with said axis add to 90°, and further including postobjective lens in the path of said beam of light having its principal axis tilted from perpendicularity to said axis by θ T .
Claim 30
Dependent Claim
39 words
Hologon scanner apparatus which comprises a planar substrate having a diffraction grating formed therein, means for rotating said grating about an axis, and means for adjustably disposing said grating at a predetermined acute angle with respect to said axis.
Claim 31
Dependent Claim
39 words
Hologon scanner apparatus which comprises a planar substrate having a diffraction grating formed therein, means for rotating said grating about an axis, and means for adjustably disposing said grating at a predetermined acute angle with respect to said axis.
Claim 32
Dependent Claim
14 words
The apparatus according to claim 29 wherein said grating is a holographic diffraction grating.
Claim 33
Dependent Claim
30 words
The apparatus according to claim 29 means providing a source of collimated coherent light which provides a beam in a direction along said axis which is incident upon said grating.
Claim 34
Dependent Claim
73 words
The apparatus according to claim 29 wherein said rotating means comprises a holder for said grating having a support surface and a side surface, means for pivotally mounting one end of said grating member on said one of said surfaces, and means for movably supporting the opposite end of said grating and on the other of said surfaces so as to pivot said member and adjust the tilt and said predetermined angle thereof.
Claim 35
Dependent Claim
52 words
The apparatus according to claim 29 wherein a plurality of said grating members are supported by said holder each displaced radially and from said axis and circumferentially from each other about said axis, and a separate one of said pivotally and movably supporting means being provided for each of said grating members.
Claim 36
Dependent Claim
51 words
The apparatus according to claim 29 wherein said rotating means comprises a holder, a first opening for light incident upon said grating and collinear with said axis, a second opening in said housing for light diffracted by said grating perpendicular to said axis, and a focusing lens in said second opening.
Claim 37
Dependent Claim
40 words
The apparatus according to claim 29 wherein said rotating means comprises a holder, a planar member having said grating on an inside surface thereof, a protective member defining a window disposed on said planar member over the inside surface thereof.
Claim 38
Dependent Claim
66 words
The apparatus according to claim 29 wherein said rotating means comprises a holder for said grating, a motor for rotating said holder, said motor having a shaft connected to said holder, a balancing mass connected to said shaft between said holder and said motor, said mass being cup-shaped and having a base connected to said shaft and sides extending away from said holder around said motor.
Claim 39
Dependent Claim
21 words
The apparatus according to claim 35 wherein said base has diametrically opposed openings perpendicular to said shaft for receiving balancing weights.
References Cited (Backward Citations)
US4239326A
Cited
US4325601A
Cited
US4289371A
Cited
US4475787A
Cited
US4475787B1
Cited
EP0144224A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-31 | 1993-01-30 | 1993-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-31 | 1997-01-30 | 1997-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-31 | 2001-01-30 | 2001-08-01 | $7700.00 | Window Closed / Lapsed |