Patent ID: 7184184

Claim:
An optical pattern generator for generating an array of figures that are offset along an offset direction, the pattern generator comprising: a first multi-faceted rotating optical element having a rotational axis and a plurality of facets that rotate around the rotational axis, wherein each facet causes an incident optical beam to generate a figure from the array of figures as the facet rotates through the optical beam; and one or more facets include an offset component that is substantially rotationally symmetric and substantially centered on the rotational axis of the first optical element and that offsets the figure along the offset direction, wherein the offset direction is generally aligned with a radial direction of the optical element; and a second multi-faceted rotating optical element having a rotational axis and a plurality of facets that rotate around the rotational axis, the second optical element located downstream of the first optical element, wherein each facet on the first optical element has a corresponding facet on the second optical element, the first and second optical elements are counter-rotating, and corresponding facets rotate through the optical beam in synchronization and cause the optical beam to generate a figure from the array of figures as the corresponding facets rotate through the optical beam; and for at least one facet on the first optical element that includes a said offset component, the corresponding facet on the second optical element includes an offset component that is substantially rotationally symmetric and substantially centered on the rotational axis of the second optical element and that offsets the figure along the offset direction.