What is beam angle?
Beam angle is the spread of light emitted from a luminaire. The beam angle is of course, expressed in degrees (∫). LEDs were once said to be very directional, but since the adoption of SMDs (Surface Mounted Light Emitting Diodes), LED chips in general have a beam angle upwards of 120∫.
Here is a short demonstration of beam angle..
What determines the beam angle of a LED lamp?
Through the use of optics, the wide spread of light from the LED chip is focused through a lens to create a controlled, narrower beam angle more suitable for different applications. Shaping the light beam can also be achieved in other ways, such as using a reflector or multi-reflectors, or a prism, in combination with lenses, to create many and various different beam patterns.
The Brightgreen Cube series uses advanced lensing techniques to cast a square beam:
Which beam angle should I select?
Beam angle is an important factor in lighting design and LED lamps are often available with multiple beam angle options.
The beam angle of the LED light you choose is determined initially by the ceiling height or distance of an object from the light source, and the lux level (brightness) that is required for a particular object or floor area.
Recommended lux levels for various tasks can be found here.
A wide beam angle combined with a high ceiling will result in a lower level of overall light as most of the light output will be absorbed by the walls and surrounding areas. The opposite is true with narrow beam angles in low height ceilings, resulting in spotting.
As an example, a kitchen bench top area may require a higher intensity of light for food preparation. To achieve high brightness on a 1 meter wide bench, you may choose a narrow beam angle to focus the light onto the area, particularly if your light is to be ceiling-mounted. If your intention is to mount your light closer, such as under cupboards, then a wider than average beam angle may well be necesary.
We recommend choosing a LED product which has the correct beam angle for your application. The easiest way to determine this is by exercising your own preference. In domestic lighting applications there is no standard to adhere to – it ís just about matching up the LED beam angle to what suits your needs.
Remember, for a given lumen output, actual lux levels at working or floor height will vary depending on the beam angle of the LED lamp used.