Test methods and principles of illuminance meters
1. Illumination test principle
Illumination is the area density of luminous flux received on the illuminated plane. Illumination juice is an instrument used to measure the illumination on the illuminated surface. It is one of the most commonly used instruments in illumination measurement.
2. The structural principle of the illuminance meter
The illuminance meter consists of two parts: a photometric head (also called a light-receiving probe, including a receiver, a V (λ) pair filter, and a cosine corrector) and a reading display.
Measurement steps and methods
In a work room, illumination should be measured at each work location (e.g., desk, workbench) and then averaged. For empty rooms or non-working rooms where the working location is not determined, if general lighting is used alone, a 0.8m high horizontal plane is usually selected to measure the illuminance. Divide the measurement area into equal-sized squares (or nearly squares), measure the illumination Ei at the center of each square, and its average illumination is equal to the average illumination at each point, that is
Where Eav - the average illumination of the measurement area, lx;
Ei ——illuminance at the center of each measurement grid, lx;
N——Number of measuring points.
Illumination uniformity refers to the ratio of the minimum illumination to the average illumination on a specified surface, that is:
In the formula, Emin——refers to the minimum illumination on the measured surface, lx.
In this experiment, the measuring point surface arranged in the room can be the designated surface, and the minimum illumination can be regarded as the minimum illumination value in the measured point.
Measure the side length of each square in the room to lm. A large room can
Where Eav - the average illumination of the measurement area, lx;
Ei ——illuminance at the center of each measurement grid, lx;
N——The number of measuring points.
Illumination uniformity refers to the ratio of the minimum illumination to the average illumination on a specified surface, that is:
In the formula, Emin——refers to the minimum illumination on the measured surface, lx.
