A compound eye simulated by microlens array was fabricated by photolithography and ion-exchange.The microlens array with 3D gradient index distribution,gapless arrangement and fine optical characteristics is buried in the convex glass substrate.Each hexagonal microlens in the array has a spot size,the center distance between two adjacent microlenses and the buried depth of 4.92 μm,0.5 mm and 0.194 mm,respectively.The measurement results show that the fabricated microlens array has symmetrical op...