HUMAN CENTRIC LIGHTING
Natural light simulation
Human Centric Lighting (HCL), which can also be called human factors in lighting, biophilia or other terms, is becoming the next big step in lighting. It may become more significant than Edison creating the light bulb, because not only can HCL provide good visual lighting quality, energy efficiency and sustainability at a reasonable cost, it can also improve circadian rhythms, short- and long-term alertness, sleep, mood, visual acuity, perception and performance–productivity. HCL provides both visual acuity and biologic benefits.
In addition to daylight, specialized fixed spectral content and tunable (dimming and Kelvin or Colour changing) LED products with advanced controls are already available and cost effective and should become standard for business, education, hospital, residential and most other applications much sooner than most people think. Within five years, and maybe as little as three, people will probably look back and wonder how they lived with that old lighting. Remember how it was before you had a smart phone!
The wellbeing and performance–productivity benefits, which may be called 'soft' savings, usually dwarf the typical 'hard' savings of lower electrical bills and reduced maintenance costs. What is very important is that HCL provides both 'hard' and 'soft' savings. HCL shows the real value of lighting and makes lighting much more than a commodity, which is how most people have been considering it for decades. So now is a perfect time for HCL, and it can be considered a wasted opportunity not to.
TW Integrated light source and driver for Tuneable white control 2700-6500 K
Harmony with the Earth’s natural lighting cycle
Claiming that better lighting can improve health is a big supposition. That said, it is not outlandish to state that carefully designed lighting can aid, even correct, circadian rhythms in human beings. Over time, people have evolved in harmony with the Earth’s natural lighting cycle, which has low light levels and low correlated Colour temperatures (CCT) in the early morning, high light levels and high CCTs at mid-day, low light levels and low CCTs during evening, and extremely low light levels and a medium CCT under moonlight. These varying light levels are at the heart of a human being’s 24-hour internal clock, otherwise defined as circadian rhythm. Until 200 years ago, 90% of our waking time was spent outside. Now most of us spend 90% of our time indoors with electric lighting. While we’re at work, our lighting is usually set at one light level with a constant CCT—this is not consistent with circadian rhythms. Without regular and direct exposure to such dynamic lighting, the circadian rhythm can be disrupted, which could lead to health issues. Specifically, light and darkness control hormone production. During the day, with a natural circadian rhythm, appropriate amounts of dopamine are secreted for pleasure, alertness and muscle coordination; serotonin for impulse control and carbohydrate cravings; and cortisol for stress response. During the night, melatonin allows for sleep, and refreshes our body. Recent research, specifically, the discovery of intrinsically photosensitive retinal ganglion cells (ipRGC) in our bodies, has been found to be very important in setting one’s internal clock, so to speak. They are especially responsive to light that is rich in blue content, the mid-day sky, for example, which can be up to 10,000K. This is particularly notable in that blue light content suppresses melatonin and encourages dopamine, serotonin, and cortisol production, meaning greater exposure to it during the day can lead people to be more alert and productive at work, or even during night shifts. At the same time, at night, such melatonin disruption can create sleep issues.
CCT change using LED light sources can be obtained, mixing warm and cool light by adjusting opposite sides intensity. It also can be obtained mixing some specific colours LED’s, getting better results, but at much higher costs.
Benefits and merit of HCL
- Individual, human centered illumination
- Natural light simulation
- Better comfort, health, productivity and sleep
- Supports circadian circle
- HCL can be implemented as standalone, as well as bigger systems solution
Human Centric Lighting control options
There are two simple ways to control dimming and Kelvin or Colour changing:
- Using a smart device like smartphone or a tablet;
- Using a push button (switch dimming).
Two-Colour temperature (2700K or 6500K) light source possible coordinate change of range and deviation from Planckian curve