Chapter 9, Problem 1OEA

Give three advantages that the Fresnel lens design has over that of a conventional lens with the same size and focal length.

To determine

The advantages of the Fresnel lens over conventional lens at same size and focal length.

Explanation of Solution

Introduction:

Fresnel lensare succession of concentric rings, consisting of an element of a simple lens.Fresnel subdivided his lens into prism like segments and then cut out the middle part of each prism.A Fresnel lens can capture more oblique light from a light source.

Major advantages of Fresnel lens over lens when both have same size and focal length are:

Fresnel lens	Conventional lens
• Low absorption: intensity of light passing the Fresnel lens gets less affected. • The Fresnel lens is light weight and it has thin construction. • Less amount of material required in manufacturing. • Low cost of production • High light collecting efficiencyby suitable arrangement.	• High absorption: intensity of light is reduced due to lens thickness • Conventional lens are heavy in weight. • Amount of material required is more in manufacturing. • Conventional lens production is expensive as compared to Fresnel lens • Less light collecting efficiency due its curved surface.