Patent ID: 11867923
Assignee: OSELA INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 12:
13. A laser line generator for projecting a low-speckle laser line at a projection plane, the laser line generator configured to received as input a laser beam having a temporal coherence characterized by a coherence length, the laser line generator comprising:
a high reflectivity reflector and a partially reflective reflector extending in parallel and defining a light cavity therebetween, the light cavity having a light input configured to receive the laser beam from the line-generating lens so that said laser beam is reflected within said light cavity for multiple passes, the laser beam having an optical path within each of said passes longer than the coherence length, each of said passes generating one of multiple incoherent sub-beams propagating in a same propagation plane;
a line-generating lens disposed in a path of the laser beam between the laser source and the light cavity and designed to fan out said laser beam in one direction within the propagation plane, each of the multiple sub-beams therefore having a fanned-out shape within said propagation plane; and
a bulk diffraction grating positioned across the propagation plane so as to intersect said multiple sub-beams, said bulk diffraction grating diffracting each sub-beam into a plurality of diffraction orders spread across said one direction within the propagation plane, thereby providing a plurality of images of said sub-beam;
whereby the plurality of images of each sub-beam forms a corresponding laser light sheet extending within the propagation plane, the laser light sheets intersecting the projection plane to define laser line elements overlapping at least partially to form said low-speckle laser line, the laser line elements having respective speckle patterns which are at least partially uncorrelated.