Beam pattern
What is a headlight’s light pattern?
The light pattern describes how a headlight distributes its light in space. It therefore does not show how much light the headlight produces in total, but rather where that light is directed. The light pattern is largely determined by the headlight’s design and optics. Reflectors and lenses can, for example, distribute the generated light widely or concentrate it more strongly in specific directions. As a result, headlights with a similar luminous flux can illuminate very different areas.
Why is the light pattern important?
The light distribution should be suited to the specific application. For a work light, for example, broad illumination of the immediate work area may be necessary. For work at greater distances, however, a more concentrated light distribution is preferable.
A high value in lumens alone does not, therefore, determine how well a work light is suited for a specific application. The distribution also influences the luminous intensity in the individual directions and the illuminance achievable on a surface.
Light Patterns for Work Lights
Various light patterns are used for work lights. These include, among others:
- Flood lighting for wide illumination of larger work areas
- Trapezoid beam for the area immediately surrounding the vehicle
- Spot for more concentrated illumination
- Mast-mounted light pattern for special requirements on material handling vehicles with a lift mast
- Dual-Beam for headlights that combine different light distributions or illumination areas
Which light pattern is suitable therefore depends on the vehicle, the mounting position, and the work area to be illuminated.
Light Patterns for High Beams
For headlights, the light pattern serves a different purpose. Here, the roadway must be illuminated according to the respective lighting function. At the same time, low beams in particular must not unduly dazzle other road users.
Typical lighting functions include low beams, high beams and fog lights.
The requirements for such light distributions are specified by regulations for public road traffic. This topic is discussed in more detail in the article Beam Patterns of Headlights.
How can a lighting scenario be evaluated?
Practical lighting cannot be fully described by a single value. In addition to luminous flux, other relevant factors include luminous intensity in various directions and illuminance at different locations.
To illustrate the actual light distribution, lighting diagrams can be used. They show how the illuminance is distributed across the illuminated area. The mounting height and orientation of the spotlight also influence where its light falls on the work surface.