Illuminance meters' measurement units and circumstances of use
Many customers will say that if I want to buy a lux meter, they will naturally ask what the unit of the lux meter is! Now briefly introduce the illuminance. Illuminance is a unit that reflects the intensity of light. Its physical meaning is the luminous flux irradiated on a unit area. The unit of illuminance is the number of lumens (Lm) per square meter, also called Lux (Lux): 1Lux=1Lm/m2. It can be seen from the above formula that Lm is the unit of luminous flux, which is defined as the amount of light radiated by the surface area of 1/60 square meters of pure platinum within a solid angle of 1 steradian at the melting temperature (about 1770°C).
The above explanation of the illuminance unit seems to be very theoretical, and it is generally difficult to understand. In order to have a more perceptual understanding of the amount of illuminance, let me give an example. A 100W incandescent lamp emits a total luminous flux of about 1200Lm. The illuminance values at 1m and 5m can be obtained according to the following steps: The area of a hemisphere with a radius of 1m is 2π×12=6.28 m2, and the illuminance value at 1m away from the light source is: 1200Lm/6.28 m2=191Lux. Similarly, the area of a hemisphere with a radius of 5m is: 2π×52=157 m2, and the illuminance value at a distance of 5m from the light source is: 1200Lm/157 m2=7.64Lux.
General conditions: In summer, it is about 100,000LUX in the sun; on cloudy days, the outdoor illuminance is 10,000LUX; the indoor daylight illuminance is 100LUX; our illuminance on the desktop 60cm away from the 60W desk lamp is 300LUX; the illuminance of the live broadcast room of the TV station is 1000LUX; The illuminance is 10LUX; the illuminance of street lamps at night is 0.1LUX; the candlelight illuminance (at a distance of 20cm) is 10-15LUX.
Speaking of this, everyone should have a more perceptual understanding of the illuminance meter unit. In fact, the illuminance meter is widely used in factories, schools, libraries, commercial buildings, hotels, commercial exhibition halls, laboratories, computer rooms, etc. , These places must use illuminance meters. It can be exaggerated to say that as long as there is bright light, illuminance meters may be used to measure the current illuminance. Now I will give you a more suitable place illuminance reference value.
Sunny day: 30000~300000LUX Production workshop 10~500LUX
Cloudy day: 3000LUX Office 30~50LUX
Sunrise and sunset: 300LUX Restaurant 10~30LUX
Full moon: 0.3~0.03LUX Corridor 5~10LUX
Starlight: 0.0002~0.00002LUX parking lot 1~5LUX
Dark night: 0.003~0.0007LUX
Under normal circumstances, we are more comfortable in the illuminance environment of about 250-750LUX. Too high or too much illuminance will also damage human eyes. The most direct one is myopia. Reading for a long time or using your eyes excessively in the environment is also worthy of our attention.
Units and application conditions of illuminance meters
The scope of application of the illuminance meter
Illumination is closely related to people's lives. For example, sufficient light can prevent people from accidents. Conversely, too dark light can cause human fatigue far more than the eyes themselves. Uncomfortable or poor lighting conditions are therefore one of the leading causes of accidents and fatigue. Existing statistics show that about 30% of all occupational labor accidents are directly or indirectly caused by insufficient light. The lighting of the stadium (stadium) must be very strict. Too strong or too dark light will affect the effect of the game.
