The present invention provides an eyepiece. The eyepiece is composed of one lens, which comprises a first surface and a second surface that are opposite, wherein, the first surface is a curved surface, and the second surface is a Fresnel structure surface; the Fresnel structure surface is formed by a plurality of annular zones that are sequentially arranged, to form a sawtooth surface, and each of the annular zones is formed by a working surface and a non-working surface, the working surface is an aspheric surface, and the non-working surface is a straight bevel; and the eyepiece satisfies the following conditional expression: 85<FOV<130, and 0i5; wherein, FOV is a maximum angle of view of the eyepiece, and i is the angle between the non-working surface of the ith annular zone and the optical axis.

The present invention provides an eyepiece. The eyepiece is composed of one lens, which comprises a first surface and a second surface that are opposite, wherein, the first surface is a curved surface, and the second surface is a Fresnel structure surface; the Fresnel structure surface is formed by a plurality of annular zones that are sequentially arranged, to form a sawtooth surface, and each of the annular zones is formed by a working surface and a non-working surface, the working surface is an aspheric surface, and the non-working surface is a straight bevel; and the eyepiece satisfies the following conditional expression: 85<FOV<130, and 0i5; wherein, FOV is a maximum angle of view of the eyepiece, and i is the angle between the non-working surface of the ith annular zone and the optical axis.

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.

An installation for improving the binocular visual field includes a structural element located at a distance from the observer equal to or greater than the observer's interpupillary distance. The structural element is provided with at least one through aperture, in which an optical system is applied that has two convergent lenses, between which a divergent lens is centrally interposed, the distance between each of the convergent lenses and the central divergent lens being such as to make the optical system of a neutral afocal type.

An observation optical system includes a display element, and an eyepiece lens disposed on an eyepoint side with respect to the display element. The eyepiece lens includes a first negative lens having strongest negative refractive power among lenses included in the eyepiece lens, a first positive lens disposed adjacent to a display element side of the first negative lens, and a second positive lens disposed closest to the display element side among positive lenses disposed on the eyepoint side with respect to the first negative lens. The number of lenses included in the eyepiece lens is greater than or equal to five. The observation optical system satisfies predetermined conditional expressions.

An observation optical system includes a display element, and an eyepiece lens disposed on an eyepoint side with respect to the display element. The eyepiece lens includes a first negative lens having strongest negative refractive power among lenses included in the eyepiece lens, a first positive lens disposed adjacent to a display element side of the first negative lens, and a second positive lens disposed closest to the display element side among positive lenses disposed on the eyepoint side with respect to the first negative lens. The number of lenses included in the eyepiece lens is greater than or equal to five. The observation optical system satisfies predetermined conditional expressions.

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.

An ultra-wide angle camera lens is provided. The lens includes, from an object side to an image side: a first lens with negative refractive power, an image-side face of the first lens being concave; a second lens with negative refractive power, an image-side face of the second lens being concave; a third lens with positive refractive power, an object-side face of the third lens being convex; a fourth lens with positive refractive power, an image-side face of the fourth lens being convex; and a fifth lens with negative refractive power, an image-side face of the fifth lens being concave. The lens satisfies: 0.05<f/f1<0; and 1.2<ImgH/f<2, in which, f represents an effective focus length of the ultra-wide angle camera lens, f1 represents an effective focus length of the first lens L1, and ImgH is half of a diagonal line of an effective pixel region on an imaging face.

An ultra-wide angle camera lens is provided. The lens includes, from an object side to an image side: a first lens with negative refractive power, an image-side face of the first lens being concave; a second lens with negative refractive power, an image-side face of the second lens being concave; a third lens with positive refractive power, an object-side face of the third lens being convex; a fourth lens with positive refractive power, an image-side face of the fourth lens being convex; and a fifth lens with negative refractive power, an image-side face of the fifth lens being concave. The lens satisfies: 0.05<f/f1<0; and 1.2<ImgH/f<2, in which, f represents an effective focus length of the ultra-wide angle camera lens, f1 represents an effective focus length of the first lens L1, and ImgH is half of a diagonal line of an effective pixel region on an imaging face.