Method and apparatus for contact image sensing
First Claim
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1. A contact image sensor comprising:
- a waveguiding structure for propagating light in a first direction comprising, in series disposed in a layer sandwiched by transparent substrates;
a first clad medium, a first core;
a switchable grating clad having a plurality of switchable grating regions;
a second core; and
a second clad medium;
electrodes applied to opposing surfaces of said transparent substrates, wherein at least one of the electrodes is patterned into a set of parallel elements orthogonally traversing said first and second cores;
a light source optically coupled to said first and second cores;
a platen in optical contact with said waveguiding structure; and
a detector optically coupled to said first and second cores;
wherein switchable grating regions overlapped by a first voltage-addressed electrode element are operative, in their diffracting state, to diffract TIR light from said first core into a path to an outer surface of said platen; and
wherein switchable grating regions overlapped by a second voltage-addressed electrode element are operative, in their diffracting state, to diffract TIR light reflected from said platen into a TIR path to said detector along said second core.
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Abstract
A contact image sensor having a waveguiding structure for propagating light in a first direction including, in series, a first clad medium, a first core, a switchable grating clad, a second core, and a second clad medium sandwiched by transparent substrates, patterned parallel electrode elements orthogonally traversing the waveguides, a light source, a platen and a detector. Switchable grating regions overlapped by a first voltage-addressed electrode element diffract TIR light from the first core towards the platen. Switchable grating region overlapped by a second voltage-addressed electrode element diffract TIR light reflected from the platen into a TIR path within the second core.
786 Citations
20 Claims
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1. A contact image sensor comprising:
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a waveguiding structure for propagating light in a first direction comprising, in series disposed in a layer sandwiched by transparent substrates;
a first clad medium, a first core;
a switchable grating clad having a plurality of switchable grating regions;
a second core; and
a second clad medium;electrodes applied to opposing surfaces of said transparent substrates, wherein at least one of the electrodes is patterned into a set of parallel elements orthogonally traversing said first and second cores; a light source optically coupled to said first and second cores; a platen in optical contact with said waveguiding structure; and a detector optically coupled to said first and second cores; wherein switchable grating regions overlapped by a first voltage-addressed electrode element are operative, in their diffracting state, to diffract TIR light from said first core into a path to an outer surface of said platen; and wherein switchable grating regions overlapped by a second voltage-addressed electrode element are operative, in their diffracting state, to diffract TIR light reflected from said platen into a TIR path to said detector along said second core. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of making a contact image measurement comprising the steps of:
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providing; a waveguiding structure for propagating light in a first direction comprising, in series disposed in a layer sandwiched by transparent substrates; a first clad medium; a first core; a switchable grating clad having a plurality of switchable grating regions; a second core; and a second clad medium; electrodes applied to opposing surfaces of said transparent substrates, wherein at least one of the electrodes is patterned into a set of parallel elements orthogonally traversing said first and second cores; a light source optically coupled to said first and second cores; a platen in optical contact with said waveguiding structure; and a detector optically coupled to said first and second cores; coupling said light into a TIR path in said waveguiding structure; contacting a region on the external surface of said platen using an external material; setting first and second electrode elements to a first voltage state and all other voltage-addressed electrodes set to a second voltage state; diffracting TIR light from said first core into a path to the platen outer surface using switchable grating regions overlapped by said first electrode element; diffracting light reflected from one of said region or said platen external surface into a TIR path in said second core using switchable grating regions overlapped by said second electrode element; transmitting said reflected light to said detector. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification