Patent ID: 8213085

Claim:
An image sensor device, comprising: a substrate having at least one photosensor therein for sensing a light source; and an anti-reflection structure disposed on the substrate, comprising: a first dielectric layer of a first refractive index, having a plurality of protrusions randomly arranged on a top surface thereof, wherein the plurality of protrusions and the intervals therebetween have an average size smaller than the wavelength of the light source; and a second dielectric layer of a second refractive index different from the first refractive index, having a bottom surface conformally attached to the top surface of the first dielectric layer and a plurality of protrusions randomly arranged on a top surface thereof, wherein the plurality of protrusions of the second dielectric layer and the intervals therebetween have an average size smaller than the wavelength of the light source; wherein the plurality of protrusions of the second dielectric layer is not aligned with that of the first dielectric layer.