What is human centric lighting？

Scientific research indicates that light is one of the main driving forces of the circadian system, whether it is natural sunlight or artificial light sources, they are all can trigger a series of physiological rhythm reactions. As we all know, natural light is the best light, now, the HCL artificial light which we always mentioned concepts come as close to this proposal as possible. Lighting influences people's heath in different degree through visual and non-visual effects. Hence, advocated "Human centric lighting", improve the quality of light and comfort is very important practical significance.

What’s more, with the develop of the scientific understanding, through HCL (Human Centric Lighting), we can also improve and enhance the conditions and quality of people's work, study and life, and promote mental and physical health, and adjust people’s daily rhythms and improve their motivation, well-being, and productivity.

In the long history of human development, people have evolved under the sun. In the process, humans have adapted to sunlight and its highly diverse effects, just as they have adapted to natural circadian rhythms.

As recently as the year 2000, a new type of photoreceptor cell was discovered in the eye, which plays an important role in the biological and non-visual effects of light. The "new" receptor, a type of light-sensitive ganglion cell that is not involved in the actual visual process, responds specifically to the short-wave "blue" region of the spectrum, which are about 480 nm. Since its discovery, science and industry have devote themselves to understand the effects of non-vision on humans, and the current state of knowledge is increasingly reflected in the use of light.

So, let's look at the photoreceptor cell in the retina:

The retina contains three types of photoreceptors: color-sensitive cone cells, light-sensitive rod cells and blue-sensitive ganglion cells.

Human eyes have three cone cell types, with each type dedicated to receiving either blue, green or red light. This allows most people to tell the difference between different colored objects.

Rod cells help measure brightness, recognize different wavelength. Rod cells are much more numerous than cone cells and are vastly more sensitive to light.

Like rods and cones, these ganglion cells are found in the retina. They respond specifically to the short-wave "blue" region of the spectrum, which are about 480 nm.

The ganglion cells especially sensitive to the blue light component are in the lower region of the retina. They are not involved in the visual process; however, they serve as signal transmitters for our "inner clock".

At daylight, Blue light can give you a stimulating effect, and give you a stimulating effect that keeps people focused during the day and during work hours. But blue light at the wrong time can also be extremely harmful to the body. At night, it can suppress the secretion of melatonin and wreak havoc on our circadian rhythms.

Therefore, it is the highest state of lighting product design, manufacturing and implementation to adjust reasonable spectrum and light color for special people and special application.

People's "biological clock" changes according to the earth's rotation, the circadian rhythm is a change of life activity with a cycle of about 24 hours. The physiological function of human body, learning and memory ability, mood and work efficiency also have obvious fluctuation in circadian rhythm. It is closely related to human activities. Disruption of circadian rhythms causes appetite descent, lower work efficiency and more accidents.

Therefore, the current people-oriented lighting applications have been more and more mentioned. People-oriented lighting is based on human behavior, visual effect and physiological and psychological research, and develop more scientific, more efficient, more comfortable and more healthy lighting products and solutions. HCL lighting is about being able to personalize and control the light to suit your needs and increase your wellbeing. LEDs' digital nature makes them relatively easy to tune to settings that might support circadian needs.

What are the benefits of Human Centric Lighting?

Scientists at the university of Toronto in Canada and northwestern university in the United States randomly assigned participants to a brightly room and a dark room.

The researchers found that the difference in emotional expression between the two groups is related to the perception of heat light. Psychologists believe that too much light makes it easier for both parties to detect and amplify aggression each other. It also makes people more sensitive to emotional speech. In the place with darker light, both sides see each other not quite clear, the precaution is less, people get closer to each other than place with brighter light.

Human Centric Lighting...

--- Helps the human body to synchronize with the “natural day/night rhythm”

--- Spectral quality of light modulates emotional responses in humans

--- Enhance people’s performance and productivity, make them feel wellbeing

--- A low carbon / no mercury/ quite sustainable

--- Better visual acuity and allow clearer vision for longer

Human-centered lighting provides full spectrum, no stroboscopic light, and has strict requirements for the distribution of light. According to circadian rhythms, people need light of different color temperatures at different time periods.

1. Benefits in industry and the office

Based on Circadian Rhythms, light can be adjusted according to time. It can help stimulate employee's activity and create a comfortable, healthy and efficient working environment.

In the morning, the office and industry lighting system simulate natural daylight to refresh employees. Over time, the intensity of the lighting will gradually weaken. After lunch, the lighting intensity is strengthened again to enhance the work vitality of employees. The light source is 5000K cold color temperature and the illumination is 780lux.These subtle changes not only help to improve the level of energy saving, improve the comfort of employees, but also ensure the eye comfort of employees.

Recently published studies in the office environment even show potential for productivity increases of 10 percent if HCL is implemented as part of a holistic approach together with other improvements in the working environment.

2. Benefits in education and schools

Schools utilize HCL to both calm students and to keep them alert depending on the time of day.

In the early morning, the right light and better lighting environment can improve students' alertness and concentration in class and reduce drowsiness during the day.

To provide higher light intensity and color temperature at appropriate time can help improve sleep quality, thereby improving learning.

3. Benefits in the medical and healthcare

There can be no substitute for good lighting. Good lighting can assist doctors in their treatment and paramedics in their work, help the elderly improve their vision, help patients in their care, help them recover, balance their circadian rhythms, and help balance their mindsets and hormones.

Lighting in nursing homes, care facilities and rehabilitation centers can firstly consider safety and visibility. The emotional atmosphere created by the lighting is also important: the lighting needs to make the nursing home more comfortable. In rehabilitation centers, lighting can consolidate therapy and promote rehabilitation.

For the staff, bright lights aid diagnosis, and dim lights aid recovery. People-oriented lighting provides the best working lighting environment, which can help doctors and staff work, improve efficiency and bring happiness to employees.

Conclusion

Today, when LED products have become the mainstream in the lighting industry, although the harm of blue light, the glare and flicker are also still existing. People’s concern about LED lighting has also shifted from "energy saving" to "health and comfort".

The non-visual effect of LED is more closely related to human health. Its influence on human physiological rhythm and biological effect and led people to rethink the definition of lighting quality.