Patent ID: 7433126

Claim:
An apparatus for improving quality of an image display by reducing laser speckle effects through reducing coherence of a laser, the apparatus comprising: a reflective spatial light modulator configured to have an image signal input; an optical component configured to introduce an optical path difference between a plurality of laser beams originating from a laser beam that is greater than or equal to a coherence length of the laser beam, the optical component comprising: a polarizing separator configured to accept a polarized laser beam comprising a first polarized component and a second polarized component and spatially separate the first polarized component of the polarized laser beam from the second polarized component of the polarized laser beam by directing the first polarized component and the second polarized component in different respective first and second directions; an optical path difference generator configured to accept the first polarized component from the polarizing separator and delay the first polarized component with respect to the second polarized component to develop a first optical path difference between the first polarized component and the second polarized component, the first optical path difference being greater than a coherence length of the polarized laser beam, wherein the first optical path difference is developed by directing the first polarized component through a series of mirrors and back toward the polarizing separator; wherein the polarizing separator is further configured to combine the first and second polarized components with the first optical path difference therebetween to form a low coherence laser beam; and parallel reflection surfaces configured to accept the low coherence laser beam and generate the plurality of laser beams from the low coherence laser beam, at least some of the plurality of laser beams being delayed by the parallel reflection surfaces to introduce a second optical path difference between each of the plurality of laser beams, the second optical path difference being greater than the coherence length of the polarized laser beam; and a deflecting optical component configured to direct the plurality of laser beams to the reflective spatial light modulator such that the plurality of laser beams converge and focus on the reflective spatial light modulator at different angles as viewed from a perspective along the longitudinal direction of the spatial light modulator, the first optical path difference and the second optical path difference serving to reduce the coherence of the plurality of laser beams.