OPTO-MECHANICAL LIGHT BAR SPATIAL FREQUENCY
Original Publication Date: 1990-Feb-28
Included in the Prior Art Database: 2004-Apr-05
Xerox Disclosure Journal
The spatial resolution of conventional light bars; i.e., liquid crystal shutter arrays or light emitting diode (LED) arrays, is fixed during the manufacturing process. The cost and complexity of these devices increases with increasing spatial resolution. A scanning configuration which enables an imaging resolution virtually independent of the light bar spatial resolution is shown in Figure 1. An image bar 8 has a stationary horizontal slit 10 which is in parallel with the light axis of bar 8 and a moving diagonal slit 12 superimposed over slit 10. A moving spot of light is generated from left to right as the diagonal slit 12 moves from top to bottom. The spot size is determined by the overlapping slit areas 14. Referring to Figure 2, elements 10 and 12 are repeated in register with pixels 18 of a light bar such that a series of flying spots are generated when the diagonal slits 12 are in motion. The motion required to generate the moving spot can be provided by a rotating endless loop (i.e., cylinder, flexible belt, etc.) moving at a constant velocity or by an oscillating member. When oscillatory motion is used to generate the moving spot, the shape of the diagonal slit can be adjusted such that the spot scans at a constant velocity; i,e, during acceleration or deceleration.