Customized optical Fresnel lens for lighthouses

What is Fresnel lens?

Fresnel lenses consist of a series of concentric grooves etched into plastic. Their thin, lightweight construction, availability in small as well as large sizes, and excellent light gathering ability make them useful in a variety of applications. Fresnel lenses are most often used in light gathering applications, such as condenser systems or emitter/detector setups. They can also be used as magnifiers or projection lenses in illumination systems, and image formulation.

A Fresnel (pronounced fray-NEL) lens replaces the curved surface of a conventional optical lens with a series of concentric grooves. These contours act as individual refracting surfaces, bending parallel light rays to a common focal length (Figure 1). As a result, a Fresnel lens, while physically narrow in profile, is capable of focusing light similar to a conventional optical lens but has several advantages over its thicker counterpart.

Applications of fresnel lens

• Light Collimation

A Fresnel lens can easily collimate a point source by placing it one focal length away from the source. In a finite-conjugate system, the grooved side of the Fresnel lens should face the longer conjugate because this produces the best performance.

• Light Collection

One of the most common applications for a Fresnel lens is the collection of solar light, which is considered very nearly parallel (an infinite-conjugate system). Using a Fresnel lens for light collection is ideal for concentrating light onto a photovoltaic cell or to heat a surface. For example, a Fresnel lens can be used for popular home maintenance such as heating a home or pool! In these cases, the overall surface area of the lens determines the amount of collected light.

• Magnification

Another common application for a Fresnel lens is magnification. It can be used as a magnifier or projection lens; however, due to the high level of distortion, this is not recommended. Also, the image quality does not compare to that of a higher-precision system given the amount of distortion.

While commonly found in solar applications, Fresnel lenses are ideal for any application requiring inexpensive, thin, lightweight positive lens elements. Fresnel lenses are not new technology, but their pervasiveness has increased with improvements in manufacturing techniques and materials. Fresnel lenses are truly unique optical lenses which make them a great tool for a range of interesting and fun optical designs.

VY provide a wide renge of Fresnel lens, welcome to contact us with your drawing or design!