What Is a Light Curve?

Definition of light distribution curve:

Light distribution curve

It refers to the light intensity distribution of light sources (or lamps) in all directions of space.

Light distribution curves generally have three representation methods: one is polar coordinate method, the other is rectangular coordinate method, and the third is equal light intensity curve.

A. Polar coordinate light distribution curve:

On the photometric plane passing through the center of the light source, the light intensity values of the lamp at different angles are measured. From a certain angle

Polar coordinate light distribution curve

As a function, the light intensity of each angle is marked with a vector, and the connection connecting the top of the vector is the polar coordinate light distribution curve of the lighting fixture. If the lamp has a rotational symmetry axis, only the light intensity distribution curve on one photometric surface passing through the axis can be used to explain the light intensity distribution in space.

If the light distribution of the lamp in space is asymmetric, the light intensity distribution curves of several photometric planes are needed to illustrate the spatial distribution of its light intensity.

B. Cartesian coordinate light distribution curve:

For concentrating lamps, because the light beam is concentrated in a very narrow spatial solid angle, it is difficult to express the spatial distribution of its light intensity with polar coordinates. Therefore, the right-angle light distribution curve is used to represent the light intensity map. I, the beam angle is represented by the horizontal axis. If it is a lamp with a symmetrical axis of rotation, only one light distribution curve is required. If it is an asymmetric lamp, multiple light distribution curves are required.

Cartesian light distribution curve

C. Light intensity curve:

The curve that connects the tops of vectors of equal light intensity is called an equal light intensity curve, and the values of the adjacent equal to light intensity curves are arranged in a certain proportion. A graph composed of a series of equal light intensity curves is called an equal light intensity Figures. Commonly used diagrams include circular, rectangular and positive arc diagrams. Since the rectangular network diagram can illustrate both the light intensity distribution and the regional distribution of light quantity, the iso-intensity curve graphs currently used for floodlights are rectangular network diagrams, which we will not introduce here.

Light intensity curve