Contact image sensor using switchable bragg gratings

Abstract

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.

Description

REFERENCE TO EARLIER APPLICATIONS[0001]This application claims the priority of U.S. Provisional Patent Application No. 61 / 629,587 entitled FURTHER IMPROVEMENTS TO CONTACT IMAGE SENSORS with filing date 6 Jan. 2012.[0002]This application incorporates by reference in its entirety the U.S. Provisional Patent Application No. 61 / 573,066 by the present inventors entitled IMPROVEMENTS TO to HOLOGRAPHIC POLYMER DISPERSED LIQUID CRYSTAL MATERIALS AND DEVICES with filing date 24 Aug. 2011 which is also referenced by the Applicant's docket number SBG104.BACKGROUND OF THE INVENTION[0003]The present invention relates to an imaging sensor, and more particularly to a contact image sensor using electrically switchable Bragg gratings. This application incorporates by reference in its entirety PCT Application Number: PCT / GB2011 / 000349 with International Filing Date: Nov. 3, 2011 entitled BIOMETRIC SENSOR by the present inventors.[0004]A contact image sensor is an integrated module that comprises an i...

AI Technical Summary

Benefits of technology

[0007]It is an object of the present invention to provide a portable, high resolution, lightweight contact image sensor for generating images in the field.

Problems solved by technology

Fingerprinting using the traditional method of inking a finger and applying the inked finger to paper can be extremely time-consuming.

Problems can arise due to the quality of inked images.

For example, applying too much or too little ink may result in blurred or vague images.

Further, the process of scanning an inked image can be time-consuming.

While the fingerprinting systems disclosed in the foregoing patents are capable of providing optical or optical and mechanical fingerprint images, such systems are only suitable for use at a central location such as a police station.

Such a system is clearly not ideal for law enforcement and security applications where there is the need to perform an immediate identity and background check on an individual while in the field.

In general current contact image sensor technology tend to be bulky, low in resolution and unsuitable for operation in the field.

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