Low mass warpage free eyepiece

An eyepiece comprising:

• a first lens element axially aligned with a second lens element and a third lens element;
• the first, second and third lens elements are sequentially positioned between a viewer and an object;
• the first lens element is formed as a doublet having two cemented surfaces;
• the second lens element is a meniscus lens having at least one lens surface composed of an aspheric surface, wherein a peripheral portion of the aspheric surface has a sagittal depth that is greater than a sagittal depth at another portion of the aspheric surface,
• the aspheric surface has a distance of more than seven diopters from the surface of the object, and
• the convex and concave surfaces of the second lens element form a nearly concentric shell with a nearly uniform cross section, resulting in nearly constant internal stress;
• the third lens element is a biconvex lens, and
• the first, second and third lens elements include a positive refractive power.

A night vision device including an image superimposed on a screen surface and an eye pupil (EP) plane for viewing the image, the night vision device including a lens system comprising:

• first, second and third lens elements sequentially located on an axial line between the EP and the screen surface,
• the first lens element including a doublet having two cemented lens elements,
• the second lens element including two even aspheric surfaces forming a nearly concentric shell with a nearly uniform cross section, and
• the third lens element including a biconvex lens of oppositely facing symmetrical surfaces.