US4496831A — Portable laser scanning system and scanning metho…

Claim 1

Independent Claim 205 words

A light-weight, high-speed, miniature scanning device for repetitively scanning light, comprising: (a) a scanning motor having a stator, a rotor, and an elongated shaft operatively connected to the rotor for joint movement about an axis which extends along the elongation of the shaft; (b) light-reflecting means mounted on the shaft for joint movement; (c) means for magnetically generating a centering force which acts on the rotor to urge the shaft and light-reflecting means to a center position, said magnetically-generating means including means for establishing at the stator and the rotor respective magnetic fields which interact to cause the magnetic field of the rotor to align itself with the magnetic field of the stator; and (d) motor control means for repetitively driving the shaft and light-reflecting means thereon in alternate circumferential directions about said axis to respective scan positions angularly spaced from said center position, said motor control means including means for electromagnetically moving the rotor against the action of the centering force in one circumferential direction about said axis over an arc length less than 360°, and thereupon for electromagnetically moving the rotor against the action of the centering force in the opposite circumferential direction about said axis over an arc length less than 360°.

Claim 2

Dependent Claim 205 words

A light-weight, high-speed, miniature scanning device for repetitively scanning light, comprising: (a) a scanning motor having a stator, a rotor, and an elongated shaft operatively connected to the rotor for joint movement about an axis which extends along the elongation of the shaft; (b) light-reflecting means mounted on the shaft for joint movement; (c) means for magnetically generating a centering force which acts on the rotor to urge the shaft and light-reflecting means to a center position, said magnetically-generating means including means for establishing at the stator and the rotor respective magnetic fields which interact to cause the magnetic field of the rotor to align itself with the magnetic field of the stator; and (d) motor control means for repetitively driving the shaft and light-reflecting means thereon in alternate circumferential directions about said axis to respective scan positions angularly spaced from said center position, said motor control means including means for electromagnetically moving the rotor against the action of the centering force in one circumferential direction about said axis over an arc length less than 360°, and thereupon for electromagnetically moving the rotor against the action of the centering force in the opposite circumferential direction about said axis over an arc length less than 360°.

Claim 3

Dependent Claim 71 words

The scanning device of claim 1, wherein the stator includes a pair of stator coil windings; and wherein the rotor is constituted of a magnetizable material; and wherein the establishing means includes means for applying a generally constant electrical signal to one of the stator windings to generate a first magnetic field, and means for magnetizing the rotor to generate a second magnetic field which interacts with said first magnetic field.

Claim 4

Dependent Claim 13 words

The scanning device of claim 2, wherein the rotor is a permanent magnet.

Claim 5

Dependent Claim 80 words

The scaning device of claim 2, wherein the motor control means includes means for applying a periodic electrical signal of time-varying amplitude to the other of the stator windings, said motor control means being operative to drive the shaft and light-reflecting means thereon to scan positions whose angular spacing from said center position is a function of the amplitude of the periodic signal, and at a speed which is a function of the rate of change of the periodic signal.

Claim 6

Dependent Claim 36 words

The scanning device of claim 4, wherein the motor control means includes feedback means electrically connected to the other stator winding for driving the shaft and light-reflecting means thereon at a uniform linear rate of speed.

Claim 7

Dependent Claim 49 words

The scanning device of claim 4, wherein the periodic signal has positive- and negative-sloped sections, and wherein the motor control means is operative to drive the shaft and light-reflecting means thereon in said one and said opposite circumferential directions in dependence on the sloped sections of the periodic signal.

Claim 8

Dependent Claim 15 words

The scanning device of claim 6, wherein the periodic signal has a triangular waveform characteristic.

Claim 9

Dependent Claim 64 words

The scanning device of claim 4, wherein the periodic-signal-applying means is operative to generate a third magnetic field of one polarity to interact with said second magnetic field of the rotor to move the same in said one circumferential direction, and of the opposite polarity to interact with said second magnetic field of the rotor to move the same in said opposite circumferential direction.

Claim 10

Dependent Claim 35 words

The scanning device of claim 1, wherein the motor control means reciprocally oscillates the shaft and light-reflecting means thereon to scan positions, each being angularly offset from the center position on the order of 5°.

Claim 11

Dependent Claim 35 words

The scanning device of claim 1, wherein the motor control means reciprocally oscillates the shaft and light-reflecting means thereon at a rate of speed which is on the order of one hundred oscillations per second.

Claim 12

Dependent Claim 23 words

The scanning device of claim 1, wherein the establishing means includes means for adjusting the strength of the magnetic field of the stator.

Claim 13

Dependent Claim 53 words

The scanning device of claim 11, wherein the stator includes a stator coil winding, and wherein the establishing means includes means for applying a generally constant electrical signal to the stator coil winding, said adjusting means being operative to change the amplitude of the generally constant signal applied to the stator coil winding.

Claim 14

Dependent Claim 75 words

The scanning device of claim 1, wherein the motor control means is operative to drive the shaft and light-reflecting means thereon to scan positions angularly spaced apart to sweep the light to be scanned over an enlarged field of view which is larger than the field of view required to be scanned so that the shaft and light-reflecting means are driven in a generally linear manner over said field of view required to be scanned.

Claim 15

Independent Claim 186 words

A method of repetitively scanning light, comprising the steps of: (a) mounting a light-reflecting means on an elongated shaft operatively connected to a rotor for joint movement relative to a stator about an axis which extends along the elongation of the shaft; (b) magnetically generating a centering force which acts on the rotor to urge the shaft and light-reflecting means to a center position by establishing at the stator and the rotor respective magnetic fields which interact to cause the magnetic field of the rotor to align itself with the magnetic field of the stator; (c) electromagnetically moving the rotor against the action of the centering force in one circumferential direction about said axis over an arc length less than 360°; (d) electromagnetically moving the rotor against the action of the centering force in the opposite circumferential direction about said axis over an arc length less than 360°; and (e) alternately repeating steps (c) and (d) in a repetitive, rapid manner to drive the shaft and light-reflecting means thereon in alternate circumferential directions about said axis to respective scan positions angularly spaced from said center position.

Claim 16

Independent Claim 186 words

A method of repetitively scanning light, comprising the steps of: (a) mounting a light-reflecting means on an elongated shaft operatively connected to a rotor for joint movement relative to a stator about an axis which extends along the elongation of the shaft; (b) magnetically generating a centering force which acts on the rotor to urge the shaft and light-reflecting means to a center position by establishing at the stator and the rotor respective magnetic fields which interact to cause the magnetic field of the rotor to align itself with the magnetic field of the stator; (c) electromagnetically moving the rotor against the action of the centering force in one circumferential direction about said axis over an arc length less than 360°; (d) electromagnetically moving the rotor against the action of the centering force in the opposite circumferential direction about said axis over an arc length less than 360°; and (e) alternately repeating steps (c) and (d) in a repetitive, rapid manner to drive the shaft and light-reflecting means thereon in alternate circumferential directions about said axis to respective scan positions angularly spaced from said center position.

Claim 17

Dependent Claim 54 words

The scanning method of claim 14, wherein said establishing step includes the step of applying a generally constant electrical signal to a stator coil winding of the stator to generate a first magnetic field, and the step of magnetizing the rotor to generate a second magnetic field which interacts with said first magnetic field.

Claim 18

Dependent Claim 74 words

The scanning method of claim 15, wherein said steps (c) and (d) include the step of applying a periodic electrical signal of time-varying amplitude to another stator coil winding to drive the shaft and light-reflecting means thereon to scan positions whose angular spacing from said center position is a function of the amplitude of the periodic signal, and at a speed which is a function of the rate of change of the periodic signal.

Claim 19

Dependent Claim 49 words

The scanning method of claim 16, wherein the periodic signal has positive- and negative-slope sections, and wherein steps (c) and (d) are performed to drive the shaft and light-reflecting means thereon in said one and said opposite circumferential directions in dependence on the sloped sections of the periodic signal.

Claim 20

Dependent Claim 65 words

The scanning method of claim 16, wherein steps (c) and (d) are performed by generating a third magnetic field of one polarity to interact with said second magnetic field of the rotor to move the same in said one circumferential direction, and of the opposite polarity to interact with said second magnetic field of the rotor to move the same in said opposite circumferential direction.

Claim 21

Dependent Claim 38 words

The scanning method of claim 14, wherein steps (c) and (d) are performed by reciprocally oscillating the shaft and light-reflecting means thereon to scan positions, each being angularly offset from the center position on the order of 5°.

Claim 22

Dependent Claim 38 words

The scanning method of claim 14, wherein steps (c) and (d) are performed by reciprocally oscillating the shaft and light-reflecting means thereon at a rate of speed which is on the order of one hundred oscillations per second.

Claim 23

Dependent Claim 24 words

The scanning method of claim 14, wherein the establishing step includes the step of adjusting the strength of the magnetic field of the stator.

Claim 24

Dependent Claim 29 words

The scanning method of claim 21, wherein the adjusting step includes changing the amplitude of a generally constant electrical signal applied to a stator coil winding of the stator.

Claim 25

Dependent Claim 24 words

The scanning method of claim 14, wherein steps (c) and (d) are performed by moving the rotor at a uniform linear rate of speed.

Claim 26

Dependent Claim 73 words

The scanning method of claim 14, wherein step (e) is performed by driving the shaft and light-reflecting means thereon to scan positions angularly spaced apart to sweep the light to be scanned over an enlarged field of view which is larger than the field of view required to be scanned so that the shaft and light-reflecting means are driven in a generally linear manner over said field of view required to be scanned.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-01-29	1988-07-30	1989-01-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-01-29	1992-07-30	1993-01-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-01-29	1996-07-30	1997-01-29	$7700.00	Window Closed / Lapsed

Portable laser scanning system and scanning methods

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag