An image-sensor structure is provided. The image-sensor structure includes a substrate, a plurality of photoelectric conversion units formed in the substrate, a plurality of separated color filters formed above the substrate and the photoelectric conversion units, a first light shielding layer surrounding the separated color filters, and a first conductive polymer element blended with a low-refractive-index component filled between the individual separated color filters and between the all separated color filters and the first light shielding layer, wherein the first conductive polymer element is electrically connected to a grounding pad.