Efficacy is a quantity often used to describe how efficiently a light fixture (or even an LED) is producing light.

At Carclo Optics the optical effciency is determined as the total luminous flux collected by a hemisphere placed over the optical assembly divided by the total lumen output of the LED source(s).

This is a notional measure of the distance from a light source.  It occurs when the observation plane is much further from the source than 10x the largest transverse dimension within the sourc

A measure of the width of a distribution defined as the separation of the data points on either side of the peak which have values equal to 10% of the maximum.

A measure of illumination used to describe how much light is falling within a given area. 1 Foot-Candle = one lumen per square foot

these allow a designer to replace the outputs from a mixture of different optic types and merge these into one single-optic to give unique, non-symmetrical illumination patterns, for example Street

A thin optical lens consisting of concentric rings of segmental lenses and having a short focal length. These are typically designed for visible or near infra-red wavelengths.

The full angular width of a beam at 50% of the peak value.

The full angular width of a beam at 10% of the peak value.

A measure of the width of a distribution defined as the separation of the data points on either side of the peak which have values equal to 50% of the maximum.

Human Centric Lighting (HCL) is a human-centered lighting concept for interiors that takes into account both the visual and the emotional and non-visual effects of light.

The IES file is a photometric file typically used to describe the light distribution from any optic, lighting fixture or source. Certain optical simulation packages (e.g.