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Advantages of Fresnel Lens

Fresnel lens present in the overhead projector focuses the beam of light produced by the projection lamp. It projects itself to the optics in head assembly. Actually, a thin piece of plastic magnifying lens present in the overhead projection screen is known as th
e Fresnel lens, which is completely flat on one side and ridged on other. In most of the overhead projection screen, two pieces of thin acrylic lens are placed together, known as dual element Fresnel lens.  But in fact, these lenses were used to focus the light beam on the lighthouse lamps.

The plastic lenses are used wherever a concentrated stream of light is required. Therefore, these lenses are used in the overhead projector where a concentrated light beam is used to project an image on the wall or screen. The function of Fresnel lens can be improved by the usage of spattering technology which is suited to the requirement of micro mini lens.  It is indeed a delight to know that the performance of the lens can be calculated on the basis of coating degree and thus can be managed and controlled according to requirement.

Another advantage of the Fresnel lens is that it can easily reduce the amount of material used in building the lens in comparison to conventional spherical lens by dividing it into a set of concentric sections called Fresnel zones. Though a Fresnel lens appears to be a single glass piece, it actually is composed of numerous smaller pieces of glass. Fresnel lenses with a single piece are used in automobile headlamp, brake, parking and turn signal lenses, to name a few.  

About Fresnel Lens

In most of the overhead projection screen, two pieces of thin acrylic lens are placed together, known as dual element Fresnel lens. Initially, these lenses were used to focus the light beam on the lighthouse lamps. The plastic lenses are used wherever a concentrated stream of light is required. Therefore, these lenses are used in the overhead projector where a concentrated light beam is used to project an image on the wall or screen. The Fresnel lenses also find usage in tail light and overhead projector. You would be amazed to know that Fresnel lens can now be made of silicon wafer so that it can be used with infrared rays’ sensors. In contrast to the plastic lenses, wafer lenses can be penetrated with ease by IR rays. It can be highly sensitive by using the concentrated IR rays instead of IR ray sensors. These sensors are generally used in cars as well as clinical thermometers.

With the advancement of technology, the function of Fresnel lens can be improved by the usage of spattering technology which is suited to the requirement of micro mini lens. It is indeed a delight to know that the performance of the lens can be calculated on the basis of coating degree and thus can be managed and controlled according to requirement. Actually, the Fresnel lens can easily reduce the amount of material used in building the lens in comparison to conventional spherical lens by dividing it into a set of concentric sections called Fresnel zones. Though a Fresnel lens appears to be a single glass piece, it actually is composed of numerous smaller pieces of glass. Fresnel lenses with a single piece are used in automobile headlamp, brake, parking and turn signal lenses, to name a few.

You would be surely amazed by the numerous applications of the Fresnel lenses. The lenses have found a great use in preserving solar energy for numerous energy requirements. The right use of the lenses can transmit at least 70 to 80 percent of the direct sunlight which comes on earth. The lenses are also used in high concentrated Photovoltaic systems where they concentrate sunlight to intensities of 300 suns and more. 

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The Fresnel Lens and the Lighthouse

The earliest application of the Fresnel lens is to the lighthouse.  It was originally developed by a French physicist named Augustin-Jean Fresnel, who was famous for the lens adapted to the lighthouse for decades.  The design enables the construction of lenses for large aperture and short focal length, and at the same time, without the weight and volume of material that would be required in conventional lens design.  Since he was an engineer who contributed to the establishment of the theory of wave optics, with the studied of the behavior of light both theoretically and experimentally, he was honored by his country with using his name to the lighthouse Fresnel lens.  

What is the relationship between the lighthouse and the Fresnel lens?  Actually, the Fresnel lens can be seen quite often in daily life.  If you work with an overhead projector, you will find the lens sits under the glass where you lay the transparencies.  Most of the people think that as a magnifying glass yet I can’t say you’re wrong, because the idea of the Fresnel lens in the overhead projector is mainly to focus the bean of the light produced by the projection lamp, and to project it to the optics in the head then on to the screen.  The biggest advantage of the Fresnel lens, compare to magnifying lens, is that the former one is a single thickness all the way across while the later one has tapers down to nothing at the edges.

So, like the other lenses, you will need to clean the lens for sure.  Most of the Fresnel lenses are marked on one side indicating which side goes toward the lamp.  Before you clean it, you have to know how to remove the lens from the overhead projector.  Remember, never use the glass cleaner on the Fresnel lens because the chemical elements might destroy the plastic lens badly.  The best way to clean the lens is to use a soft cloth dampened with water or cleaner that is allowed by the manufacturer of the Fresnel lens.  While you reinstall the lens correctly, handle it carefully to avoid scratches or other types of damages.  This movement seems easy, but once you accidentally make a scratch on the lens, the careless might cost you way more expensive than purchase a new overhead projector.