An ocular optical system includes a first lens element and a second lens element from an eye-side to a display-side in order along an optical axis. The first lens element and the second lens element each include an eye-side surface and a display-side surface. The eye-side surface of the first lens element has a convex portion in a vicinity of the optical axis. The second lens element has negative refracting power. The ocular optical system satisfies 1.5|f2/f1| and 250 millimeters/EFL10, wherein f2 is the focal length of the second lens element, f1 is the focal length of the first lens element, and EFL is the effective focal length of the ocular optical system.

An ocular optical system includes a first lens element and a second lens element from an eye-side to a display-side in order along an optical axis. The first lens element and the second lens element each include an eye-side surface and a display-side surface. The eye-side surface of the first lens element has a convex portion in a vicinity of the optical axis. The second lens element has negative refracting power. The ocular optical system satisfies 1.5|f2/f1| and 250 millimeters/EFL10, wherein f2 is the focal length of the second lens element, f1 is the focal length of the first lens element, and EFL is the effective focal length of the ocular optical system.

A head-mounted display device includes a first display portion disposed in front of a pupil of a viewer and displaying a first image, a second display portion disposed on an ear side of the viewer and diagonally in front of the pupil and displaying a second image, a first lens disposed between the pupil and the first display portion for projecting a first image onto the pupil, and a second lens disposed between the pupil and the second display portion for projecting a second image onto the pupil. The second lens is disposed adjacent to the first lens on the ear side of the viewer, and an optical axis of the first lens and an optical axis of the second lens intersect with each other at an angle ranging from 30 degrees to 80 degrees inclusive.

A cloaking device includes a prism and a light guide. The prism is attachable to an article and is configured for directing around the article a light ray reflected from an object that is blocked from view. The prism has an object surface and an article surface spaced opposite the object surface. The guide is disposed on solely the object surface and has a refraction surface at least partially spaced apart from the object surface. The guide is configured for directing the ray through the prism such that the object is not blocked from view. The refraction surface and the ray define a first angle therebetween of less than 90. The guide is formed from a first transparent material having a first refractive index and the prism is formed from a second transparent material having a second refractive index that is greater than or equal to the first refractive index.

A viewing assembly specifically, but not exclusively, structured for viewing through a solid, glass or transparent material panel includes a housing and an outer section collectively disposed in an operative position, respectively on and inner and outer surfaces of the panel. Inner and outer ends of the housing respectively include aligned first and second viewing apertures. A viewing member, structured for restricted, unidirectional viewing there through, is disposed within the housing in aligned relation to the first and second viewing apertures, and may be in the form of a one way mirror. The outer section is disposed in visually covering relation to the inner end of the housing and includes a third viewing aperture, wherein the first, second and third viewing apertures and the viewing member are collectively disposed in visually aligned relation along a predetermined line-of-sight extending through the panel from an interior to an exterior thereof.

Disclosed is an eyepiece optical system with a large field-of-view angle, and a head-mounted display apparatus. The eyepiece optical system comprises a first lens group (G1) and a second lens group (G2) which are arranged coaxially and successively along an optical axis from a human eye to an image source and meet a certain focal length relationship. A distance (D12) between the first lens (L1) and the second lens (L2), a focal length relationship of lenses within the second lens group (G2) and the material properties of various lenses meet a certain relationship. The eyepiece optical system has the advantages of large aperture, large field-of-view, high resolution, low distortion, and small size, etc., and is suitable for a head-mounted display and similar apparatuses.

Disclosed is an eyepiece optical system with a large field-of-view angle, and a head-mounted display apparatus. The eyepiece optical system comprises a first lens group (G1) and a second lens group (G2) which are arranged coaxially and successively along an optical axis from a human eye to an image source and meet a certain focal length relationship. A distance (D12) between the first lens (L1) and the second lens (L2), a focal length relationship of lenses within the second lens group (G2) and the material properties of various lenses meet a certain relationship. The eyepiece optical system has the advantages of large aperture, large field-of-view, high resolution, low distortion, and small size, etc., and is suitable for a head-mounted display and similar apparatuses.

Provided are a compound lens and a display device including the same. The compound lens may improve image quality by providing a higher resolution in a central image region and a lower resolution in a peripheral image region. The compound lens includes a central lens portion and at least one peripheral lens portion, the at least one peripheral lens portion surrounds the central lens portion, the central lens portion has a first focal length, the at least one peripheral lens portion has a second focal length, and the first focal length is greater than the second focal length.

A novel optical design form for a biocular lens arrangement having a large format focal plane and large eye relief zone is disclosed. Key aspects of a large format biocular lens arrangement are: Lightweight plastic design for all but outermost lens, where more durable glass is desired; a large front aperture for comfortable eye motion; improved eye channel overlapping field of view with minimal distortion; and full color resolution.

A novel optical design form for a biocular lens arrangement having a large format focal plane and large eye relief zone is disclosed. Key aspects of a large format biocular lens arrangement are: Lightweight plastic design for all but outermost lens, where more durable glass is desired; a large front aperture for comfortable eye motion; improved eye channel overlapping field of view with minimal distortion; and full color resolution.