LED lighting and its effects on health Did you know that LEDs can help improve your quality of life? What light can be used for very varied therapeutic treatments? What can improve our performance at work and in studies? But not everything is positive. Do you know that a luminaire with poor design can be a risk factor for diseases such as cancer or epilepsy? Does your manipulation create long-term damage to vision? Whether you are a lighting system designer, user or installer, what is exposed in this post is of interest to you. The designers can know the characteristics of the next generation of luminaires, which in addition to efficiency provide the good light, the light we need. The consumers will be able to learn what features it must meet a set of LED lighting to suit your needs and does not harm your health or that of your family. And the installers will be able to know some tips to make good installations and not take risks when handling luminaires with LEDs. What parameters of light can affect our health? Light can affect our health in several ways The intensity of light, with two possible effects: Warm up our eye Glare Stroboscopic effects, or flickering of light. The light spectrum Let's analyze each one for the case of the LEDs. Effects of light intensity LED. Warmening of the eye? We started with good news. Normal use of an LED does not produce a warming effect on the eye. It is clear that we speak of LEDs of illumination and not LEDs laser that yes that can be dangerous
Dazzling? The light concentration of an LED can easily exceed 1000 times that of traditional light sources. These levels of intensity can certainly cause annoying glare that is not harmful to health, except in potentially dangerous situations such as driving vehicles. So we must prevent direct light from the LEDs reaching our eyes. Therefore, the recommendation is that we do not use very powerful lamps that have LEDs in sight. Installers and designers already follow visual ergonomics standards that avoid these annoying glare. How does the flicker of light affect us? The blinking of light or LED strobe effect is present in almost all sources of artificial light although our eye cannot observe it. There are studies [2] that indicate the possible effects of light blinking in humans depending on the frequency: ~ 3-70Hz, risk of epileptic seizures Up to 165Hz, risk of discomfort, headaches, vision impairment, etc. It has been shown that we perceive flickering with frequencies up to 200Hz. But its effects depend on the sensitivity of the person (not all of us are affected equally) and other parameters such as: Frequency Intensity of light (higher intensities produce a greater effect) Color of light (red and blue affect more) Modulation (difference between the maximum value and the minimum of light. Greater differences produce a greater effect) The incandescent and fluorescent bulbs (including those with low fluorescence consumption) are fed directly at 50Hz (60Hz in some countries) and therefore have flickers at the frequency of the network 50-60Hz and twice the frequency of the network 100Hz-120Hz, above what our eye can appreciate.
LEDs cannot be connected directly to the grid (except for some not very popular exceptions) and to produce light, they must be fed with a constant current of a certain value. This current is provided by an electronic circuit that receives multiple names (ballast, driver, power supply, etc.) and is responsible for ensuring that this current has the proper value and is as stable as possible. Okay, okay, but does the LED produce a light with a flicker or not? We have to distinguish two cases: Non-attenuating LED (also known by its name in English, dimming) NO (if the design is suitable). In case of having dimming: If the dimmer is of the installation with classic lighting, not all LED lamps work properly with these dimmers, so that visible and invisible blinking is possible. If the dimming function is in the LED lamp, the blinking will exist as it is the usual mode of dimming on a LED, but its frequency should be well above the 200Hz indicated above. In conclusion, the flicker is in all sources of artificial light and the LED can also have them. Assuming a correct design of the LED lamp, the flicker should be at frequencies above 200Hz to have the least effect on people. The following slowmotion video lets you observe the flicker of an LED bulb.