Electronically-controlled mechanically-damped off-resonant light beam scanning mechanism and code symbol readers employing the same

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.