Units and illuminometer application circumstances
Unit of illuminometer
Many customers will say that I want to buy an illuminometer, and naturally ask what the unit of the illuminometer is! Now let's briefly introduce illuminance. Illuminance is a unit that reflects the intensity of light, and its physical meaning is the flux of light shining on a unit area. The unit of illuminance is the number of lumens per square meter (Lm), also known as Lux: 1Lux=1Lm/m2. From the above equation, it can be seen that Lm is the unit of luminous flux, defined as the amount of light emitted by a surface area of 1/60 square meter of pure platinum at a solid angle of 1 spherical degree at a melting temperature (approximately 1770 ℃).
The explanation of illuminance units above seems very theoretical and generally difficult to understand. In order to have a more intuitive understanding of the amount of illumination, let's take an example to illustrate that a 100W incandescent lamp emits a total luminous flux of about 1200Lm. If the luminous flux is uniformly distributed on half of the sphere, the illuminance values at 1m and 5m away from the light source can be calculated as follows: a hemisphere with a radius of 1m has an area of 2 π × 12=6.28 m2, the illuminance value at a distance of 1 meter from the light source is: 1200Lm/6.28 m2=191Lux. Similarly, a hemisphere with a radius of 5m has an area of 2 π × 52=157 m2, the illuminance value at a distance of 5 meters from the light source is: 1200Lm/157 m2=7.64Lux.
General situation: In summer, it is approximately 100000 LUX under sunlight; The outdoor light intensity on cloudy days is 10000LUX; The indoor sunlight illumination is 100LUX; Our illumination on a desktop 60cm away from a 60W desk lamp is 300LUX; The lighting level in the live broadcast room of the television station is 1000LUX; At dusk, the illumination in the room is 10LUX; The illumination of street lights at night is 0.1LUX; Candlelight illumination (at a distance of 20cm) 10-15LUX.
Application range of illuminometer
Illumination is closely related to people's lives. For example, sufficient light can prevent people from accidents. On the contrary, too dark light can cause fatigue in the human body far beyond the eyes themselves. Therefore, uncomfortable or poor lighting conditions are one of the main causes of accidents and fatigue. Existing statistical data shows that about 30% of all occupational accidents are directly or indirectly caused by insufficient lighting. The lighting of the sports stadium (gymnasium) should be very strict, as excessive or dim lighting can affect the effectiveness of the competition.
