Portable laser scanning system and scanning methods having a motor amplitude regulator circuit

Claim 2

A miniature, hand-held scanning device for repetitively scanning a target, said device having a laser beam generating means, at least one high speed scanning motor, and a motor amplitude regulator circuit for controlling said scanning motor, said motor amplitude regulator circuit comprising means for operating said scanning motor at resonance, and means for automatically controlling the amplitude of oscillation of the shaft of said scanning motor, said controlling means being driven from a single feedback signal obtained from the scanning motor.

Claim 3

The scanning device of claim 1, wherein said motor amplitude regulator circuit further includes means coupled to the scanning motor for obtaining a generated voltage induced within direct current stator windings of said scanning motor to function as said single feedback signal and for providing said generated voltage to said circuit means.

Claim 4

The scanning device of claim 1 wherein said circuit means is a feedback system comprising: a means for obtaining and amplifying an induced generated voltage from the direct current stator windings of the scanning motor to function as said single feedback signal; a peak detector means for converting said amplified generated voltage to a direct current voltage signal; a different amplifier means for comparing said direct current voltage signal with a reference signal and providing an error signal output; a variable controlled resistance means for providing a variable direct current voltage signal from said error signal output; and a controlled power supply means for supplying a periodic current waveform to the ac stator windings of the scanning motor in response to said error signal to adjust the amplitude of said scanning motor shaft oscillation.

Claim 5

The scanning device of claim 3 wherein said feedback system further includes a means for providing a regulated current to the dc stator windings of said scanning motor.

Claim 6

A miniature, hand-held scanning device for repetitively scanning a target with laser light, said device having a laser beam generating means and at least one high speed scanning motor, said motor having a stator, dc stator windings, ac stator windings, a rotor, a shaft connected to said rotor having light reflecting means attached thereto and being operable to oscillate in alternate circumferential directions, and a motor amplitude regulator circuit for automatically controlling the amplitude of oscillation of the shaft of said scanning motor and for operating said motor at or near resonance, said circuit comprising: feedback means coupled to the dc stator windings for obtaining a feedback signal, said feedback signal being a generated voltage induced in the dc stator windings; amplitude error signal means coupled to said feedback means for comparing said feedback signal with a reference signal having a predetermined voltage to output an amplitude error signal representative of a difference between the amplitude of oscillation of the shaft of the scanning motor and the reference signal; and motor control means coupled to said error signal means and the ac stator windings for adjusting the amplitude of oscillation of the shaft of said scanning motor in response to the amplitude error signal.

Claim 7

A miniature, hand-held scanning device for repetitively scanning a target with laser light, said device having a laser beam generating means and at least one high speed scanning motor, said motor having a stator, dc stator windings, ac stator windings, a rotor, a shaft connected to said rotor having light reflecting means attached thereto and being operable to oscillate in alternate circumferential directions, and a motor amplitude regulator circuit for automatically controlling the amplitude of oscillation of the shaft of said scanning motor and for operating said motor at or near resonance, said circuit comprising: feedback means coupled to the dc stator windings for obtaining a feedback signal, said feedback signal being a generated voltage induced in the dc stator windings; amplitude error signal means coupled to said feedback means for comparing said feedback signal with a reference signal having a predetermined voltage to output an amplitude error signal representative of a difference between the amplitude of oscillation of the shaft of the scanning motor and the reference signal; and motor control means coupled to said error signal means and the ac stator windings for adjusting the amplitude of oscillation of the shaft of said scanning motor in response to the amplitude error signal.

Claim 8

The scanning device of claim 5 wherein said feedback means includes a motor drive integrated circuit for amplifying the induced generated voltage.

Claim 9

The scanning device of claim 6 wherein said motor drive integrated circuit includes a regulated current supply means for providing said dc stator windings of the scanning motor with a regulated current.

Claim 10

The scanning device of claim 6 wherein said feedback means further includes a peak detector circuit means for converting the induced generated voltage into a dc voltage signal.

Claim 11

The scanning device of claim 5 wherein said amplitude error signal means includes a differential amplifier for comparing the induced generated voltage and the reference signal to provide said amplitude error signal.

Claim 12

The scanning device of claim 9 wherein said amplitude error signal means further includes a voltage controlled resistance means for providing a constant dc voltage controlled resistance means for providing a constant dc voltage signal to said motor control means from said error signal means.

Claim 13

The scanning device of claim 5 wherein said motor control means includes a current supply means which supplies periodic current waveforms from said motor drive integrated circuit to said scanning motor to control the amplitude of oscillation of the shaft of said scanning motor.

Claim 16

The method of claim 12 wherein the step of obtaining a single feedback signal includes obtaining a generated voltage induced within the dc stator windings of the scanning motor.

Claim 17

The method of claim 12 wherein said adjusting step comprises comparing the amplitude of said feedback signal to a reference signal having a predetermined amplitude and changing the current supplied to the ac stator windings of the scanning motor to reduce a difference in the amplitudes of the feedback and reference signals.

Claim 20

The method of claim 15 wherein the step of obtaining said feedback signal includes amplifying the generated voltage.

Claim 21

The method of claim 16 wherein the step of obtaining said feedback signal further includes converting said induced voltage into a dc voltage signal.

Claim 22

The method of claim 15 wherein said combining step comprises comparing the generated voltage and a reference signal to provide said amplitude error signal.

Claim 23

The method of claim 15 wherein said combining step further comprises providing a constant dc voltage signal to current supply means, said current supply means outputting periodic current waveforms to said ac stator windings of said scanning motor to control the amplitude of said motor shaft oscillation.