Patent ID: 8004776

Claim:
An optical plate for an imaging camera, comprising: a first region and a second region within an effective aperture on an incidence plane or exit plane of the optical plate, wherein the optical plate is orthogonal to an optical axis of the imaging camera, has an effective aperture diameter that is the same as an effective aperture diameter of the imaging camera, and is configured to attach in front of the imaging camera to enable depth of field to be deepened, wherein the first region is an inside region of the optical plate that has a surface ratio that is 50 percent or more of the effective aperture, and has a curvature of a surface shape of the incidence plane or exit plane that increases going from the optical axis to a periphery thereof, wherein a thickness of the first region increases going from a center to the periphery thereof, such that a phase of transmitted light is increasingly delayed going from the center to the periphery thereof, and wherein a phase of light transmitted by the second region has no transmission position dependency, the second region being outside of the first region, and having a plane parallel plate shape.