Stationary coil oscillator scanning system
View Patent ↗An image scanning apparatus and a torsion oscillator are capable of operating across a dynamic range of possible operating frequencies. The image scanning apparatus uses a light source to produce a light bean, and the oscillator scans the light beam through a scanning pattern. The oscillator includes a plate member having a non-rectangular shape. At least one magnet is disposed on the plate. A surface of the plate member includes a reflective surface for reflecting a light beam. A frame is disposed in a spaced apart relation to a lower surface of the plate member. The fame includes at least one coil configured to induce an electromagnetic force on the at least one magnet to thereby oscillate the reflective surface to a rotational angle of oscillation at an oscillation frequency. The system also includes an imaging surface disposed in the path of the scanning pattern so that the light beam scans across the imaging surface, and a mechanical drive to move the imaging surface. A control system controls electric current provided to the at least one coil to achieve the oscillation.
1. A torsion oscillator scanner comprising:
a light source for producing a light beam;
a plate member having a non-rectangular shape selected from the group of elliptical, oval, racetrack, or circular, the plate member having an upper surface, a lower surface, and a rotational axis,
a frame disposed in a spaced apart relation to the lower surface of the plate member,
a mount for holding the plate number adjacent the frame,
a reflective surface located on a surface of the plate member for reflecting a light beam,
at least one magnet disposed on the plate,
at least one coil located on the frame and configured for inducing electromagnetic force on the at least one magnet when alternating current is applied to the at least one coil to thereby oscillate the reflective surface to a rotational angle of oscillation at an oscillation frequency to scan the light beam through a scanning pattern in at least first and second directions at the oscillation frequency
a receiving surface disposed in the path of the light beam in the scanning pattern for interacting with the light beam to produce information, and
control logic for controlling the oscillation of the reflective surface to oscillate the reflective surface at or near a resonant frequency of the plate member.
2. The torsion oscillator scanner of claim 1 wherein the mount further comprises a torsion spring mount for mounting the plate member on the frame and for yieldably resisting oscillation of the plate member with a torsion spring force.
3. The torsion oscillator scanner of claim 1 wherein the mount further comprises a torsion spring mount having opposed substantially co-axial silicon torsion springs for mounting the plate member on the frame and for yieldably resisting oscillation of the plate member with a torsion spring force.
4. The torsion oscillator scanner of claim 1 wherein the reflective surface has a shape selected from the group of elliptical, oval, racetrack, or circular.
5. The torsion oscillator scanner of claim 1 further comprising a laser producing the light beam in the form of a laser beam, the laser beam being dimensioned and disposed to overfill the reflective surface and produce a reflected laser beam having a cross sectional dimension defined by the size of the reflective surface.
6. The torsion oscillator scanner of claim 1 wherein the reflective surface comprises a mirror having an optical power.
7. The torsion oscillator scanner of claim 1 wherein the reflective surface comprises a concave mirror.
8. The torsion oscillator scanner of claim 1 wherein the reflective surface comprises a Fresnel lens mirror.
9. The torsion oscillator scanner of claim 1 wherein the plate member further includes one or more diffractive optical surfaces having reflective properties.
10. The torsion oscillator scanner of claim 1 wherein the reflective surface comprises multiple mirrors, each mirror having different reflective properties.
11. The torsion oscillator scanner of claim 1 wherein the light source comprises a laser producing the light beam in the form of a laser beam, the laser beam being dimensioned and disposed to overfill the reflective surface and produce a reflected laser beam having a cross sectional dimension defined by the size of the reflective surface.