Patent ID: 10429613

Abstract:
An ocular optical system includes a first lens element, a second lens element and a third lens element from an eye-side to a display-side in order along an optical axis. The first lens element, the second lens element and the third lens element each include an eye-side surface and a display-side surface. The eye-side surface of the first lens element has a concave portion in a vicinity of the optical axis. The display-side surface of the third lens element has a concave portion in a vicinity of a periphery of the third lens element. The ocular optical system satisfies 1≤TTL/ER≤10, wherein TTL is a distance from the eye-side surface of the first lens element to the display screen along the optical axis, and ER is a distance from a pupil of the observer to the eye-side surface of the first lens element along the optical axis.