OPTICAL SYSTEM, IMAGING DEVICE, AND INFORMATION CODE READER

摘要

An imaging device includes an optical system (210) which forms a primary image, an imaging element (220), and an image processor (240). The optical system (210) includes a lens (213) provided with an optical wavefront modulation surface (213a) which reduces the variation of an optical transfer function (OTF) according to an object distance or a lens having the optical wavefront modulation surface. The absolute value of the focal distance (fphase) of the lens (213) having the optical wavefront modulation surface (213a) is larger than that of the focal distance (ftotal) of the whole optical system (210) including the lens (213). As a result, the image of the object becomes a dispersed image without being focused at the imaging element (220) disposed at the focal distance (ftotal) of the optical system (210). The image processor (240) performs convolution operation of the dispersed image captured by the imaging element (220), thereby generating a high-resolution final image. The imaging device is applied to an information code reader which reads an information code.