Symmetric and asymmetric lenses
Lenses can be used to alter both beam angles and light distribution
This article will explain symmetric and asymmetric beam angles: including the applications and benefits for either type. Different lenses have interesting and unique effects and are can be used to create an ideal lighting design. Precision optical designs result in dedicated lenses, to go over the led chips, generating the resultant lit effect.
The industrial floodlight range comes with a number of options: wattage, colour temperature and beam angle. The beam angles available are either a symmetric 120° or a 100°x150° asymmetric option, achieved through the type of lens installed over the LED chips. This example will assist in providing practical examples of this theory in reality.
Fundamentally the discussion is about the pattern of light distribution which is required for a certain application. The end result of the lit effect will determine the most effective option to select.
The symmetric lens distributes the light evenly in all directions; it creates a conic shape to provide pooling of light, ideal for general area illumination. Applications including security, perimeter lighting and, to a certain degree, up-lighting will all benefit from symmetric lenses.
An asymmetric lens option generates a lighting pattern which concentrates light in a certain direction. The focussed nature of the lit effect means that more ‘useful’ light is created from the luminaire, with lower quantities of light lost from up-spill when mounted at 0° tilt.
Asymmetric lenses can (in certain instances) mean that lower wattage asymmetric products can be used in place of symmetric equivalents. This then creates a wide range of benefits, including cost and energy savings.
Asymmetric lens options are ideal for use in sports pitches, tennis courts and car parks. This is because these products generally create less indirect glare, through the provision of suitable wider area lighting, opposed to pooling of light, which creates shadows in places, if the lighting design is sub optimal.
Dedicated polar plots are available for each part code on the website. Entering the specific part code into search bar will load a pop-up with all the pieces of relevant information. There is an article written on polar plots to explain their function, their purpose and their benefits.