Although the phrase "polar curves" suggests a snow-covered landscape of rolling hills, the normal definition is rather more prosaic. Polar curves relate to mathematics and appear on graphs. They show the way in which LEDs and other bulbs distribute light.Photometrics
Lighting engineers study photometrics. This is the process for measuring the intensity of light. Such intensity varies according to how close or far you are from LEDs. Engineers use polar curves to plot the level of the intensity at any given point.
In other words, a polar curve tells an engineer how LEDS spread light across a room or surface. This distribution may be narrow, wide, indirect or direct.
The Polar Graph
Some engineers refer to a polar curve graph as a polar luminous intensity graph. Either way, the "polar" aspect of the graph applies to its polar coordinates. These fan out in wheel-like spokes at a set number of degrees from a fixed point. The LEDs are at this fixed point.
The "curve" is a visual guide to the distribution of light from the LEDs. Lines curve out from the fixed point to represent this distribution. By checking these lines against the polar coordinates, an engineer knows exactly where the light from LEDs will fall, and how intense it will be.
By using polar curves, an engineer can arrange the right number and type of LEDs for a lighting project. For example, a designer may want specific lighting effects in a room. Creating polar curves before installation gives the designer and lighting engineer a chance to check light distribution and intensity. This saves time and money, and ensures success.