An image sensor is disclosed. In some implementations, the image sensor includes a substrate including one or more photoelectric conversion elements arranged in the substrate and structured to convert light into electrical signals representing an image carried by the light, and a plurality of metal layers arranged at different distances from a surface of the substrate and located below the one or more photoelectric conversion elements, each of the metal layers including one or more metal patterns. The one or more metal patterns of the plurality of metal layers are arranged in a concave shape facing the photoelectric conversion element such that incident light reflected by metal layers converges toward the photoelectric conversion element.