CONTACT IMAGE SENSOR USING SWITCHABLE BRAGG GRATINGS

摘要

A contact image sensor having: an illumination; a first SBG array device; a transmission grating; a second SBG array device; a waveguiding layer having a multiplicity of waveguide cores separated by cladding material; an upper clad layer; and a platen. The sensor also including an optical device for coupling light from an illumination source into the first SBG array; and an optical coupler for coupling light out of the cores into output optical paths coupled to a detector having at least one photosensitive element.

主权项

1. A contact image sensor comprising the following parallel optical layers configured as a stack:
an illumination means for providing a collimated beam of first polarisation light; a first SBG array device further comprising first and second transparent substrates sandwiching an array of selectively switchable SBG column, and transparent electrodes applied to opposing faces of said substrates and said SBG substrates together providing a first TIR light guide for transmitting light in a first TIR beam direction; a transmission grating; a second SBG array device further comprising third and fourth transparent substrates sandwiching a multiplicity of high index HPDLC regions separated by low index HPDLC regions and patterned transparent electrodes applied to opposing faces of said substrates; and a platen; and further comprising: means for coupling light from said illumination means into said first TIR light guide; means for coupling light out of said second SBG array device into an output optical path; and a detector comprising at least one photosensitive element; wherein said high index regions providing waveguiding cores are disposed parallel to said first beam direction, wherein said low index HPDLC regions providing waveguide cladding, said substrate layers having a generally lower refractive index than said cores, wherein said patterned electrodes applied to said third substrate comprise column shaped elements defining a multiplicity of selectively switchable columns of SBG elements orthogonal to said waveguiding cores, wherein said patterned electrodes applied to said fourth substrate comprise elongate element overlapping said low index HPDLC. wherein said detector comprises an array of photosensitive elements, each said photosensitive element being optically coupled to at least one said core.