Units of measurement for illuminance meters and conditions of use
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 at a steradian angle of 1 degree of sphericity is the amount of light radiated.
The above explanation of the illuminance unit seems to be very theoretical and generally difficult to recognise. In order to have a more perceptual understanding of the amount of illumination, an example to illustrate, a 100W incandescent lamp, the total luminous flux emitted is about 1200Lm, if the assumption that the luminous flux is uniformly distributed in half of the sphere, then from the light source 1m and 5m at the value of the illuminance can be obtained in accordance with the following steps: radius of 1m of the hemisphere area of 2π × 12 = 6.28 m2, from the light source 1m The luminosity value at 1m from the light source is 1200Lm/6.28 m2=191Lux. Similarly, the area of the hemisphere with a radius of 5m is 2π×52=157 m2, and the luminosity value at 5m from the light source is 1200Lm/157 m2=7.64Lux.
General situation: summer in the sunlight is about 100000LUX; cloudy day outdoor illuminance is 10000LUX; indoor fluorescent lamp illuminance is 100LUX; we are 60cm away from the 60W desktop lamp on the desktop illuminance is 300LUX; TV broadcasting room illuminance is 1000LUX; dusk time room illuminance is 10LUX; nighttime street lamps illuminance is 0.1LUX; candlelight illuminance (at a distance of 20cm away) is 10-15LUX.
Speaking of which, you should have a more perceptual understanding of the illuminance meter unit should have, in fact, illuminance meter applications are very wide, factories, schools, libraries, commercial buildings, hotels, commercial exhibition halls, laboratories, computer rooms and so on, these places have to use illuminance meter, it can be an exaggeration, as long as there is a bright light in the place, it is possible to use the illuminance meter to measure the current illuminance, and now to give us a Now to give you a more applicable places illuminance reference value.
