An image sensor includes a substrate having opposite first and second sides, a multilayer structure on the first side of the substrate, and a photo-sensitive element on the second side of the substrate. The photo-sensitive element is configured to receive light that is incident upon the first side and transmitted through the multilayer structure and the substrate. The multilayer structure includes first and second light transmitting layers. The first light transmitting layer is sandwiched between the substrate and the second light transmitting layer. The first light transmitting layer has a refractive index that is from 60% to 90% of a refractive index of the substrate. The second light transmitting layer has a refractive index that is lower than the refractive index of the first light transmitting layer and is from 40% to 70% of the refractive index of the substrate.