Optical Board - Fresnel Lens

Purpose

To demonstrate construction of a Fresnel lens.◙

Equipment

Optical board with 18 inch hyperbolic and Fresnel lenses.

Images

l6-51

Description

Set up the hyperbolic convex lens with the seven-ray slit baffle so that the entire aperture of the lens is used. Then replace the regular lens with the hyperbolic Fresnel lens, on which one of the light rays uses each separate seg ment in the lens. This shows how to construct a lens which focuses like a standard double convex lens but uses much less material.