Patent ID: 10527763

Abstract:
An ocular optical system configured to allow imaging rays from a display frame to enter an observer's eye through the ocular optical system to form an image is provided. The ocular optical system includes a lens element having an eye-side surface and a display-side surface. The lens element has an optical axis extending from a display side toward an eye side. The display-side surface of the lens element adopts a Fresnel lens design. The display-side has a plurality of effective sub-surfaces and a plurality of ineffective sub-surfaces. The effective sub-surfaces are configured to allow the image rays to form an image. Each ineffective sub-surface connects two adjacent effective sub-surfaces. The ocular optical system satisfies: 25.000°≤α≤52.000°, where α represents a maximum tilting angle of the effective sub-surfaces relative to a reference plane perpendicular to the optical axis.