How to measure brightness with illuminance meter
In the equipment and use of UVLED, for the measurement and application of light intensity, we will come into contact with what lumen is. Many people may have heard of it, but they may not really understand it. Let's learn about it today.
A colleague bought a flashlight, which is very bright. He said it has 100 lumens, so I asked casually, what is a lumen? Then time seemed to stand still, he looked at me blankly, what is lumen?
Lumen, the English abbreviation is LM, it is a logistics unit that describes the luminous flux in the international unit. Physically interpreted as the total emitted luminous flux produced by candlelight within a solid angle. In fact, it can be simply understood as the brightness produced by a candle on one square meter. Therefore, the higher the lumen value, the higher the brightness.
Measuring the brightness of a light source is more important than measuring its power, as a traditional incandescent light bulb is measured in watts, which indicates how much power it uses, with more wattage meaning brighter light. And with the advent of more energy-efficient lighting fixtures, wattage isn't a good indicator of light brightness unless it's the same type of lighting fixture. This is why lighting is measured in lumens.
Lumens and watts measure different things so they cannot be truly compared directly, i.e. the measurements are completely different, but it is possible to estimate the amount of lumens produced by bulbs of different wattages, for example using a 100 watt incandescent bulb, produces About 600 lumens, while a 26 watt bulb produces the same amount when using LED bulbs. In addition, lumens are also a useful unit when purchasing lighting lamps. In the past, only brightness and darkness were used to describe the light of the purchased lamps. When you know how many lumens a bulb can produce, you can install or purchase an accurate number of lamps. .
So how can you judge the lumens of the light? This can only be measured with special instruments. Like a light meter. Its unit is lux, and the English symbol is LX. 1 lux equals 1 lumen. We may have come into contact with this illuminance meter. When inspecting the factory, the auditor will take the illuminance meter, inspection bench, production line, and warehouse to test it for you. The result may be that the light is not up to standard. As a result, it must be rectified and added lights to meet the light requirements. Standard so far.
In the optical unit, there is another term, that is candela. The English symbol is CD. It is also a unit of luminous intensity, and its relationship with lumens can be understood simply by using a flashlight. Lumens refer to whether the light emitted by the flashlight is bright or not, and candela refers to whether the light emitted by the flashlight is far away.
After seeing this, do you know more about lumens? According to experience, you can look at the specific lumen output. Small keychain flashlights emit less than 60 lumens, ordinary dry battery flashlights emit 100-200 lumens, and professional outdoor flashlights have a longer beam range and may cause damage to the eyes. The luminescence can reach 400 ~1000 lumens.
