Illuminance measuring units and operating conditions
Many customers will say, I want to buy an illuminance meter, it is natural to ask what is the unit of illuminance meter! Now a brief introduction to illuminance, illuminance a unit that reflects the intensity of light, its physical meaning is irradiated to a unit area of luminous flux, illuminance unit is the number of lumens per square metre (Lm), also known as Lux (Lux): 1Lux = 1Lm/m2. 1Lux = 1Lm/m2. As can be seen from the above formula, Lm is a unit of luminous flux, which is defined as the pure platinum at the melting temperature (about 1770 ° C), the amount of light radiated within the stereo angle of the surface area in a spherical degree of 1/60 square metres. /60 square metres of surface area in 1 spherical degree of the stereo angle of the amount of light radiated.
Illuminance Meters Requirements for Application
● Compact Size, Light Weight
Compact size and light weight are essential prerequisites for a portable illuminance meter that can be used in a wide range of applications and in a variety of locations.
Accuracy
The good and bad of the illuminance meter, and its accuracy has a relationship. Of course, it is also closely related to its price, so a reasonable price to buy a higher accuracy of the illuminance meter is necessary, generally to the error does not exceed ± 15% is appropriate.
Colour Compensation
The types of light sources are all over the place, some favour the longer wavelengths of the red high-pressure lamps, or shorter wavelengths of blue-violet system such as Daylight fluorescent lamps; there is also a more even distribution of such as incandescent bulbs series, the same illuminance meter for different wavelengths of its sensitivity may be slightly different, so the appropriate compensation is necessary.
Cosine Compensation
As we all know, the brightness of the illuminated surface is related to the angle of incidence of the light source. In the same way, when using a luminance meter to make measurements, the angle between the sensor and the incident light source will naturally have an effect on the reading of the luminance meter. Therefore, a good illuminance meter whether the cosine compensation function should not be ignored.
