Abstract: A contact image sensor whose sensory elements have similar output levels is disclosed. The sensor includes: a first region consisting of a plurality of light sensory elements situated on a silicon wafer, the light sensory elements being separated from one another by an isolation material; an implanted region formed in the silicon wafer under the first region for preventing carrier from affecting the silicon wafer; a plurality of circuitry regions formed on a portion of the silicon wafer excluding the first region, the circuitry regions being separated from one another; and a light shielding region formed on the silicon wafer between the first region and the plurality of circuitry regions.