Electronically-controlled mechanically-damped off-resonant light beam scanning mechanism and code symbol readers employing the same
First Claim
1. Apparatus for deflecting a light beam, comprising:
- an optical bench;
a scanning element of unitary construction having a base portion, a light beam deflecting portion, and a gap region disposed therebetween,said base portion being anchored with respect to said optical bench so as to permit said light beam deflecting portion to pivot about a fixed pivot point defined between said base portion and said gap region,said light beam deflecting portion having a front surface and a rear surface and being flexibly connected to said base portion by said gap region,said light beam deflecting portion having a natural resonant frequency of oscillation about said fixed pivot point and being mechanically-damped at said gap region;
a permanent magnet mounted on said light beam deflecting portion;
a light beam deflecting element mounted on said light beam deflecting portion, for deflecting a light beam falling incident upon said light beam deflecting element;
a magnetic-field producing coil disposed adjacent said permanent magnet, for producing a magnetic force field of reversible polarity in the vicinity of said permanent magnet in response to an electrical current signal flowing through said magnetic-field producing coil, at an amplitude which varies at a controllable frequency; and
an electrical circuit operably connected to said magnetic-field producing coil, and producing an electrical voltage signal which causes said electrical current signal to flow through said magnetic-field producing coil and produce in the vicinity of said permanent magnet, said magnetic force field having a polarity which varies in accordance with the amplitude and frequency of said electrical current flowing through said magnetic-field producing coil,whereby said magnetic force field interacts with said permanent magnet and forces said light beam deflecting portion to oscillate about said fixed pivot point at a controlled frequency of oscillation that is substantially equal to said controlled frequency and substantially different from said natural resonant frequency of oscillation of said light beam deflecting portion; and
wherein said controlled frequency of oscillation is different in magnitude than said natural resonant frequency of oscillation by at least 10% of said natural resonant frequency.
5 Assignments
0 Petitions
Accused Products
Abstract
Apparatus for deflecting a light beam, comprising: a scanning element having a base portion, a light beam deflecting portion, and a gap region disposed therebetween. The base portion is anchored with respect to an optical bench to permit the light beam deflecting portion to pivot about a fixed pivot point defined between the base portion and the gap region. The light beam deflecting portion has a natural resonant frequency of oscillation about the fixed pivot point and is mechanically-damped at the gap region. A permanent magnet and right beam deflating portion are mounted on the light beam deflecting portion. A magnetic-field producing coil produces a force field that interacts with the permanent magnet and forces the light beam deflecting portion to oscillate about the fixed pivot point at a controlled frequency of oscillation that is substantially different from the natural resonant frequency of oscillation of the light beam deflecting portion.
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Citations
16 Claims
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1. Apparatus for deflecting a light beam, comprising:
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an optical bench; a scanning element of unitary construction having a base portion, a light beam deflecting portion, and a gap region disposed therebetween, said base portion being anchored with respect to said optical bench so as to permit said light beam deflecting portion to pivot about a fixed pivot point defined between said base portion and said gap region, said light beam deflecting portion having a front surface and a rear surface and being flexibly connected to said base portion by said gap region, said light beam deflecting portion having a natural resonant frequency of oscillation about said fixed pivot point and being mechanically-damped at said gap region; a permanent magnet mounted on said light beam deflecting portion; a light beam deflecting element mounted on said light beam deflecting portion, for deflecting a light beam falling incident upon said light beam deflecting element; a magnetic-field producing coil disposed adjacent said permanent magnet, for producing a magnetic force field of reversible polarity in the vicinity of said permanent magnet in response to an electrical current signal flowing through said magnetic-field producing coil, at an amplitude which varies at a controllable frequency; and an electrical circuit operably connected to said magnetic-field producing coil, and producing an electrical voltage signal which causes said electrical current signal to flow through said magnetic-field producing coil and produce in the vicinity of said permanent magnet, said magnetic force field having a polarity which varies in accordance with the amplitude and frequency of said electrical current flowing through said magnetic-field producing coil, whereby said magnetic force field interacts with said permanent magnet and forces said light beam deflecting portion to oscillate about said fixed pivot point at a controlled frequency of oscillation that is substantially equal to said controlled frequency and substantially different from said natural resonant frequency of oscillation of said light beam deflecting portion; and wherein said controlled frequency of oscillation is different in magnitude than said natural resonant frequency of oscillation by at least 10% of said natural resonant frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification