Units and application conditions 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.
Speaking of this, everyone should have a more intuitive understanding of the unit of illuminance meters. In fact, illuminance meters are widely used in factories, schools, libraries, business buildings, hotels, commercial exhibition halls, laboratories, computer rooms, and other places. These places all require 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 let me give you a more applicable reference value for lighting in places.
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
In general, we are more comfortable in an illumination environment of around 250-750LUX. If the illumination is too high or too high, it can also cause harm to the eyes. The direct cause is myopia, with the vast majority of myopia
