Finding the Connection Between Tunable White and Circadian Lighting

Finding the Connection Between Tunable White and Circadian Lighting

Key Concept to Understand

Tunable white LED lighting systems afford us the ability to shift color temperature within a lighting fixture at-will, turning off one or a series of LEDs in the fixture.  The implications of this technology are clear: when we can shift the color temperature in a lighting system, it can restore our relationship with sunlight, changing the way indoor lighting affects us. Though, not all tunable white lighting systems are the same, which is why we cannot assume that they all offer the benefits of circadian lighting.

Let Sunlight Guide Artificial Light

SPD of daylight and sunet

SPD of natural daylight & sunset – NOTE DAYLIGHT peak at 482nm

To understand the differences between tunable white lighting systems and circadian lighting systems, and whether or not they can be classified in the same manner, we can start by looking at the SPD (Spectral Power Distribution) of sunlight, which describes the power of light at a given wavelength. Daylight SPD, as we will see, is extremely important to our circadian rhythms, the pattern of waking up and falling asleep that we follow every day.

Let’s think about what our most natural and healthy lifestyle would look like in terms of our circadian rhythm: we would take in sunlight during the day and then lay down in total or near-total darkness at night. When we lay down, our bodies produce melatonin as part of a natural reaction to the darkness, which keeps us running on approximately the same schedule as the sun.

In our modern world, we have disrupted this process completely. Most notably, we are now often substituting natural daylight with artificial light. Knowing how much we rely on daylight, it makes sense if possible to model artificial light after sunlight.

Blue Light is a Blight on The Typical LED

Energy-efficient and lasting almost forever, LED lighting has quickly become one of the more popular types of artificial light, but there is a secret about them that most people do not know: white LEDs are actually blue.

SPD of daylight versus LED

Daylight versus LED – NOTE BLUE spike at 450nm and trough at 482nm

It’s true.

White light from an LED is merely the result of a white phosphor coating placed over a blue LED.

When we look at and compare the SPD of LED light with the SPD of the sun (our model for healthy circadian lighting), there are some alarming differences in the “blue-light” region.

To illustrate this, compare the SPD graph shown of a typical LED with daylight; you see that there is a noticeable low point in the LED graph at 482nm.  This low point is important because science has proven that the non-visual ipRGC (intrinsically photosensitive retinal ganglion cell) receptors in our eyes are most sensitive to blue-light at this 482nm wavelength.

SPD of sunset

SPD of Sunset – NOTE low blue light level helps promote sleep

What this means is daylight from the sun helps to suppress melatonin, increasing our energy and productivity during the day.  Conversely, the blue-light level of sunlight during the evening is much lower, which encourages melatonin production and promotes sleep.

This is a good time to note that all blue light will suppress melatonin. Even the blue-light spike in a typical LED at 450nm will still disrupt your circadian rhythm at night. We cannot avoid that completely. A tunable white system using typical LEDs and trying for a circadian affect will need to make a compromise.  By adjusting the color temperature or just the light intensity, you will wind up either suppressing melatonin too little during the day or creating an uncomfortable setting high in glare and brightness.

This is because typical LEDs have a trough at 482nm and can’t achieve the power levels required to suppress melatonin without over-lighting a space and creating a glare. Take a typical neutral-white color temperature LED: if you want to use this to suppress melatonin during the day, you would need to “over-light” the space, creating glare that makes people uncomfortable.  If you choose a higher “blue-light” cool-white LED to suppress melatonin, alternatively, you would make people uncomfortable because of the blue-ish color temperature of 6500K.

A New Solution

Nichia Optisolis LEDs Used in PERFKETLIGHT

PERFEKTLIGHT uses high CRI Nichia Optisolis LEDs

It is true that LEDs represent the cutting edge of lighting systems, and tunable white lighting systems are the most innovative application of LEDs. There are distinctions that we need to draw, though: a tunable white lighting system is only as powerful as the LEDs that we find inside it. To enhance the impact of a tunable white lighting system on our circadian rhythm, we can look at the wavelengths that the LEDs are emitting.  Tweak the wavelength to the optimal point of 482nm and you can suppress melatonin without making anyone uncomfortable.

This is why tunable white lighting is such a major improvement over monochromatic white LEDs – by using the right technology, we can change the wavelengths, aligning them with the perfect wavelengths for your circadian rhythm. Next, let’s look at the specific and industry-leading way that we are accomplishing this.

The Impact of a 482nm Peak

Thanks to Nichia’s Optisolis LED, we have eliminated the trough at 482nm and filled it in with the optimal wavelength to encourage alertness. This may seem like a small difference from the wavelengths that you would find in typical white LEDs, but on the scale that your eye works, it is huge. Unlike typical white LEDs, which disrupt the circadian rhythm, the 480-490nm-peak wavelength that you find in Nichia’s Optisolis LED does not, as it suppresses melatonin during the day but facilitates low blue light in the morning and evening.

PERFEKTLIGHT SPD with Nichia Optisolis LEDs

SPD of PERFEKTLIGHT – NOTE low blue light level of warm color temperature for morning and evening versus the higher blue light level of neutral and cool-white color temperatures during daytime

When we compare Nichia’s Optisolis LED with typical white LEDs, we see that it is minimizing the blue peak and trough. On top of that, it equals the SPD of sunlight without emitting any UV radiation. For art galleries and museums, which need to avoid UV because of its damaging effect on their art and artifacts, this is good news, just as it is good news for you as you work to keep your circadian rhythm timed properly.  Thanks to tunable white lighting featuring Nichia’s Optisolis LEDs, you can take charge of your circadian rhythm, discover all the sleep that you have been missing, and step into a new and healthier life for yourself. You can wake up each morning feeling refreshed and energized, laying down in your bed at night confident that sleep troubles are not going to keep you from the rejuvenation you need.

LEDdynamics, PERFEKTLIGHT, and You

At LEDdynamics, we believe wholeheartedly in working on the cutting edge science in the lighting sector. That is why we have not only pioneered tunable white lighting – we have also sourced our LEDs from Nichia, refusing anything but the very best, knowing the impact that our tunable white lighting systems can make on all of our customers. Researching these LEDs extensively, we are championing a new ideal in tunable white lighting through PERFEKTLIGHT.

Contact us about PERFEKTLIGHT

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PERFEKTLIGHT Recognized by IES Progress Report

PERFEKTLIGHT – Recognized by IES for Breakthrough Tunable White LED Technology with Color Rendering of +96

LEDdynamics announces that PERFEKTLIGHT™ tunable white technology has been recognized in the Illuminating Engineering Society’s 2020 Progress Report.  This selection confirms the innovation as a unique and significant advancement to the art and science of lighting.

Neil Cannon Comments on PERFEKTLIGHT“Acknowledgement of PERFEKTLIGHT™ by the IES raises awareness of healthy lighting,” said LEDdynamics CEO, Neil Cannon.

Modern life has people indoors more than any other time in history.  The lack of sunlight exposure contributes to a number of health issues, including the disruption of circadian rhythms, which causes irregular sleep and wake cycles.  Tunable white lighting, which is rapidly emerging as the best type of circadian lighting, can foster improved health and wellness while indoors.

However, many applications of this technology have not been able to be deployed due to both the complexity and the cost.   LEDdynamics has engineered PERFEKTLIGHT™ to expand commercial applications by integrating patent-pending tunable white LED technology with cost-effective controls.

“PERFEKTLIGHT™ is a revolutionary tunable lighting system.  It recreates the sunlight’s effect on human circadian rhythms at precisely the right times of day,” Cannon said. “Retail testing has resulted in higher sales and happier employees who report better sleep and an improved work environment.”

Circadian Lighting PERFEKTLIGHT™ uses geographic information and time of day to continuously and automatically adjust interior lighting to match sunny skies outside.  The Spectral Power Distribution (or “fingerprint”) of daylight changes continually throughout the day – from sunrise to sunset. PERFEKTLIGHT™ replicates this dynamic progression of sunlight, while traditional monochromatic lighting does not.  Across the tuning range, the color rendering is maintained between 96 and 98 and Correlated Color Temperature (CCT) is corrected to follow the Blackbody locus.  These features promote health and wellness and make recognizing colors as though seen under sunlight.

PERFEKTLIGHT™, with corrected CCT tuning and “Set and Forget” controls, is straightforward to install and cost-effective, making it ideal for new construction and retrofit applications in healthcare, retail, residential, education, and grocery venues.


Tunable LED Light Improves Health in Nursing Home

Tunable White LED Lighting Poised to Improve Life in Nursing Homes

More than anyone else, people in nursing homes struggle to find high-quality sleep, which is especially disheartening because we know that elderly people are more susceptible to health issues, which poor sleep can exacerbate. While this is a complex issue, there is a good deal that we can do about it because we understand how our brains decide when it is time for us to be awake and when it is time for us to be asleep. It comes down to our circadian rhythm, which melatonin regulates. Naturally, it was the absence of the sun that would initiate melatonin production. This is still true, but other variables have come into play.

Let’s dive into this a little deeper. When we talk about melatonin production and sleep, we need to talk about the circadian rhythm too. This is what determines how our brain directs our sleeping and waking functions, and while you may be able to fall asleep when you are outside the rhythm, sleep quality will suffer. This is because the hypothalamus inside the brain struggles to operate properly when the circadian rhythm is out of alignment with reality, and when its suprachiasmatic nucleus (SCN) cannot work in conjunction with the optic nerve behind the eye, it receives unclear signals about light and darkness and makes inaccurate conclusions about day and night.

Circadian SCN & Eye

For thousands of years – the vast majority of history, even the majority of some older people’s lives – all of this information would have been interesting but certainly not immediately relevant. If you experienced minimal or no exposure to artificial lighting, how could this information have been relevant? Today, though, we all come into contact with artificial lighting, almost constantly, and at night, that spells trouble for the circadian rhythm. Just when your brain is trying to figure Color Tuning in Smartphonesout when it is time for you to go to sleep and when it is time for you to wake up, you are looking at your phone or your tablet, exposing yourself to blue light, and throwing your circadian rhythm out of sync.

For younger, healthier people, it is possible to throw the circadian rhythm out of sync and still fall asleep at night. It is possible in the way that it is possible to eat unhealthy foods for a day without falling ill, but it is not the ideal. In nursing homes, on the other hand, sleep challenges are already widespread. If you have ever visited a nursing home yourself, then you may have observed these challenges in action, the difficulties that many residents face when they are trying to sleep or when they are trying to go about their days and inadvertently falling asleep. As one study out of the University of California put it, “Although older community-dwelling adults are more likely to take naps than younger adults, the typical long-term care resident shows a pattern of wakefulness that is frequently interrupted by brief periods of sleep.”

When sleep issues already run rampant, any solutions could prove groundbreaking, and in nursing homes, sleep challenges do run rampant. Before the influx of blue light that smart phones and smart pads ushered in, sleep quality was already critical to elderly people because of the health issues that arise from poor sleep. Falling short of their sleep requirements and falling ill or sleeping during the day, during inopportune moments, elderly people may try to make up for sleep that they missed at night, but as research has shown, this concept is false: we cannot make up for sleep once we have missed it. As you surely know yourself if you have ever tried to go through a Monday on only two or three hours of Sunday-night rest, quality of sleep impacts quality of life, but what else does it mean for people? How does a smooth circadian rhythm affect our lives?

Irritability, poor concentration, poor memory, slower reaction times, decreased performance: these are all well-known symptoms of low-quality sleep. In the elderly – in particularly the elderly who suffer from dementia, a condition already associated with the same symptoms – these symptoms can become overwhelming, to the point that research published in Neuropsychiatric Disorders and Treatment concluded that over a ten-year period, there was a link between insomnia and elderly suicide.

Knowing this, we also know that we need to do something to respond to these challenges. The Pandora’s box of blue light is open, and there is no turning back. We can encourage people to avoid their phones in the evening over and over again, but we need something more active to respond to these challenges effectively. To determine how we can respond to these challenges, it is useful to look beyond circadian rhythm and its theoretical effects and consider the real-world effects of circadian rhythm in nursing homes – and how circadian lighting can make a difference.

Circadian Lighting Effects in Nursing Home

To figure out what circadian lighting could mean to nursing homes, we can look to the research. One study from the US Department of Energy is especially encouraging, pointing to the game-changing numbers that they have seen circadian lighting drive and the inimitable impact that this lighting can have on populations where the rates of sleep disturbances are high – as we said, even affecting a majority of all the people within the population.

ACC Care Center Circadian Lighting Report on Sleep Effects

In this study, out of the ACC Care Center, researchers consider the residents of the 99-bed facility as a whole. They stated, “The objective was to test a strategy for measuring and documenting light exposure for typical residents, and to evaluate the collected data in terms of multiple metrics for human circadian responses over the course of a day.” This is an important point to make because, as they also point out, this science is still new. Newer than the blue-light-emitting devices that exacerbated these sleep issues in the first place.  Dependable tunable white lighting is an innovation that, unfortunately, most nursing home professionals and administrators have not heard of. When we see the undeniable effects of circadian lighting in nursing homes, that is the only explanation that would make any sense, too.

For their study, researchers for the US Department of Energy depended on three models for circadian wellness, each of which purports to tell us how light is impacting sleep quality: melanopic/photopic (M/P) ratios, equivalent melanopic lux (EML), and circadian stimulus (CS). Let’s consider each of these models.

For an M/P ratio, we are considering the melanopic content and the photopic content, both measured at the eye. Sometimes, experts will refer to this as the “blue-cyan content” because that is what it is describing, the blue light that is at an eye. When the M/P ratio is high, it leads to wakefulness, and when the M/P ratio is low, it leads to sleepiness.

An EML, meanwhile, accounts for the radiant watts that our ipRGC photoreceptors detect and the photopic content at the eye – again, higher equating to more wakefulness and lower equating to more sleepiness.

Then, there is CS, which measures the suppression of melatonin, once again the higher values equating to wakefulness and the lower ones equating to sleepiness.

The researchers for the ACC Sleep Center study used what we call “spectrophotometers” (Konica-Minolta CL-500a) read the radiant energy data necessary to calculate M/P ratio, EML, and CS, detecting light in the nursing home environment so that they could compare their readings to the objective reports that the nursing home residents submitted regarding their sleep quality. From this, we can extrapolate calculations and objective reports into conclusions about the effects of different types of lighting on elderly people’s sleep quality.

Making a point of controlling the static lighting at 4100K, the researchers strove to imitate the eye lighting conditions in the morning for all residents so that they could say more definitively that they were observing results caused through nighttime lighting conditions. This means that when we are reviewing the statistics and conclusions in this study, we can say with a high degree of confidence that we are reviewing the effects of nighttime lighting conditions as well.

The researchers also worked from an assumption that has become mostly universal by now among those who are familiar with the different types of lighting and their effects: low, warm-color light leads to stronger melatonin production, which leads to higher sleep quality.  Pictures were taken of the same corridor, but at different times of the day to provide a visual example of the tuning range (Photo from Report is Below).

Tunable LED Lighting in Nursing Home Hallway

Time and again, the outcome was clear: tuned white lighting made a difference. Anything but indecisive, their research showed a significant gap between the sleep disturbances that residents experienced when exposed to old styles of lighting and the sleep disturbances their counterparts experienced when exposed to cutting-Improve Sleep with Circadian LED Lightingedge tuned white lighting. Static lighting, repeatedly, correlated with higher incidences of sleep disturbances in this nursing home.

It is important to realize that the static lighting the researchers used was no different from the static lighting that nearly all nursing homes are using at this very moment. The environments that they replicated for their study would have been indistinguishable from many other real-world nursing home environments, which begs the question: how many elderly people are suffering needlessly? How many people in nursing homes are laying awake at night, unable to get their circadian rhythms in balance, unable to fix their melatonin production, falling asleep in the middle of the next day when their families are visiting them?  What are the repercussions of sleep disturbance in regards to the nursing staff?

The gap between static lighting and tuned white lighting, it turns out, is a chasm. You may be wondering, How serious could the difference have been? As far as science goes, the answer is very. Exposed to tuned white lighting, residents experienced only half as many sleep disturbances as they would have exposed to static lighting – 1.8 versus 3.6. In research of this kind, that is the type of determinative difference that researchers are looking for, either to confirm their hypothesis or deny it. When only half as many nursing home residents are experiencing sleep disturbances while exposed to some stimulus, that stimulus merits further attention, to say the least.

Sleep Results from Circadian Lighting Test

Researchers were even more direct in their conclusions about the study, stating that “The intervention likely worked to reduce sleep disturbances in the 5% to 7% of residents with many severe sleep disturbances.” While 5% to 7% is a minority of all residents, it would be difficult to overstate how life-altering it could be to reduce their severe sleep disturbances because, again, these challenges result in more than irritability and poor concentration. Over time, severe sleep disturbances, like insomnia, can lead to a number of irreversible health issues, up to and including suicide.

The researchers, reviewing their M/P ratio, EML, and CS calculations, determined that tunable white lighting was effective at cutting down on blue-cyan content at night and at delivering higher levels of blue-cyan content in the morning and during the day, when wakefulness becomes important. In every way, this lighting seemed capable of improving quality of life at the ACC Care Center, calculation after calculation turning out positive and in favor of the newer lighting type.

Astoundingly, the researchers for the US Department of Energy also reported that “[I]n an institutional setting with shared rooms, such as the nursing center in this study, improving the sleep of a few residents may have a ripple effect on roommates and closely located others.” Put another way, we can create a wave of health benefits by improving nursing home residents’ sleep, thinking beyond the immediate and measurable figures that we are examining in M/P ratio, EML, and CS calculations. It is rational to assume, therefore, that in a nursing home, everyone benefits from tuned white lighting.

Lighting to Improve Life


Tunable White LED Bulb & StripTunable white lighting – often referred to, appropriately, as circadian lighting – has shown promise as a sleep aid in a way that no other innovation has. When we think of the defining role that smart devices are playing in our lives, their smorgasbords of blue light filling us up and damaging our melatonin production whether we like it or not, this means that tunable white lighting could be the answer. This could be the technology that we all need to reclaim higher-quality sleep for ourselves and make a pointed shift away from the low-quality sleep that would come to define this era otherwise.

In nursing homes, the concerns that we are raising rise beyond the level of convenience and desire. Because of the high rates of insomnia and sleep disturbances that already permeate these environments, we need solutions now. These are pressing circumstances, and if we ignore them, we are setting ourselves up for disaster. Likewise, if we respond to these circumstances effectively, we can do incredible things – even saving lives. There is an opportunity to make life better for people, showing our friends and family in nursing homes that we care and that we are willing to take steps to show that.

Circadian lighting, or white tuned lighting, is the next frontier in lighting, and it seems right that nursing homes would find themselves pioneering into it. Blue-cyan content, shaping wakefulness and sleepiness the way that it does, ought to come back under the control of the professionals and caregivers who think of nursing homes as their calling. For the residents who depend on them, this innovation could mean the difference between one life and another – between high-quality sleep and something else.

The statistics are clear. Today, nearly half of all adults age 60 and up report insomnia, and more than half report some form of sleep disturbance. For those who think of insomnia and sleep disturbances as natural byproducts of age, we would point to the facts that the US Department of Energy and other researchers have uncovered in their studies. Better is possible, achievable through modest interventions. Something as straightforward as changing out some lighting can slash sleep disturbance rates in half, returning PERFEKTLIGHT - Tunable White LED Lightingelderly people to sleep habits and circadian rhythms that are truly natural, correcting the flaws that blue-light saturation has introduced.

PERFEKTLIGHT is our answer to all of the questions and demands that this research has presented. We have engineered our tuned white lighting system with the human body’s circadian rhythm at the forefronts of our minds. Because we are so enthusiastic about the difference that this innovative lighting can make, we have devoted ourselves to perfecting it. Our system not only draws on the benefits of tuned white lighting in general but also enhances and optimizes the technology, taking it to a whole new level.

To learn what PERFEKTLIGHT could mean for your nursing home and how it could improve quality of sleep and quality of life for the residents who rely on you as a decision-maker, contact us here.

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Understanding Circadian Rhythm and How Tuning LEDs Can Increase Health & Wellness

How Light Effects Circadian Rhythm, the Quality of Your Sleep and Health

When it comes to advancements in lighting solutions, Human Centric Lighting (HCL) applications are driving innovation at LEDdynamics.  Through technological refinements, the maximum levels of energy savings from LEDs have been mostly achieved across the industry.  Now, for the team at LEDdynamics, our R&D has shifted to engineering a commercially viable tunable white LED technology that can harness the power of sunlight to improve our health and wellness.

Now more than ever we’re living life indoors under artificial light, which is negatively affecting our health and wellness. A typical tunable white lighting system, with its ability to dynamically shift color temperature, does gets us one step closer to replicating sunlight. However, the purpose of this article is not to debate if tunable white light provides the benefits of circadian lighting, but to go into detail about and understand how light, in general, affects our circadian rhythm and the dramatic effect it can have on our sleep and overall health.

The Importance Of Circadian Rhythms

To understand the benefits of circadian lighting, it is vital to first understand the function of the human body’s circadian rhythm. The circadian rhythm is controlled by the brain’s hypothalamus. Connecting the nervous system to the endocrine system (the system responsible for hormone regulation), the hypothalamus operates via a small bundle of cells called the suprachiasmatic nucleus (SCN). The SCN is connected to the optic nerve behind the eye and receives information about the varying levels of light and darkness from our environment throughout the day and night.

When light enters your eyes first thing in the morning, the SCN responds immediately and kick-starts its “daytime mode”. Signals are sent that raise your heart rate, your temperature, and your blood pressure to wake you up and get your body moving.

Circadian SCN & Eye

Among waking up, circadian rhythms signal your body to engage in various actions, such as when to rise, eat, sleep, letting your body know when you’re most alert, and many other vital biological functions.

These rhythms also tell your body to delay the release of hormones like melatonin. Melatonin is a hormone released by the pineal gland that helps induce feelings of tiredness and promotes good quality sleep.

Unfortunately, in our always-on, digital world, our rhythms can get a bit out of sorts. If your circadian rhythm is out-of-sync with your daily schedule (also known as being “not entrained”), then it is likely that the time you wake-up and fall asleep each day will be delayed by increasing 15-minute intervals.

For the average person to feel healthy and energized each day, the National Sleep Foundation recommends between seven and nine hours of sleep every night for adults. Unfortunately, it is estimated that at least two-thirds of people around the world are not getting the recommended amount of sleep to live productive, energized lives. Globally, this is a significant percentage. If you are routinely getting less than eight hours of sleep, you are likely damaging your health and well-being without even noticing.

Two Types of Sleep: REM & NREM

At night, your body experiences two types of sleep rhythms – NREM and REM sleep.

Stage three of NREM is the beginning of deep sleep. This is the most restorative stage of sleep where your body works to repair muscle and tissue as well as build energy for the next day.

After stage three of NREM comes REM sleep, an acronym of Rapid Eye Movement sleep. REM is also known popularly as the dream state. At this stage in your sleep cycle, your eyes will often jerk quickly in different directions, your breathing becomes irregular, and your blood pressure and heart rate increase. Brain wave activity during this stage of sleep looks almost identical to your brain waves while awake. REM sleep is important for memory function and learning because at this stage of sleep your brain consolidates and processes information you encountered the day before.

For perspective, it takes your body approximately 90 minutes to cycle through all sleep stages. So, if you fall asleep at 9:00 p.m. you’ll enter REM sleep around 10:30 p.m. You repeatedly cycle through these stages at night, storing memories and repairing muscle damage, until you wake up the next morning.

Light Source Effects on Circadian Rhythm and REM Sleep

Your circadian rhythm plays an important part in ensuring proper access to REM sleep stages. If your circadian rhythm is not synced to the natural rhythm of the world around you, there can be physical, mental, and behavioral consequences. Lack of proper circadian regulation can cause insomnia or excessive daytime sleepiness – a symptom similar to that of jetlag.  In some cases, excessive sleep alterations can even cause nausea, irritability, and depression. (For a comprehensive list and explanation of negative effects read to the end of this post.)

In our 24/7 digital world, we often continually receive light into our eyes well beyond sunset. This can be in the form of household lighting like lamps and ceiling lights, or from our backlit screens like TVs, smartphones, and tablets. A study published in the journal PLoS One found that excessive screen time beyond the earth’s natural rotation light cycle is associated with poor sleep quality. Many of our devices give off a bright, artificial light that can negatively impact your circadian rhythm by tricking your body into believing that it is still daytime. This causes a delay in natural sleep processes such as the secretion of melatonin – the natural signal to your body to prepare for sleep. However, it’s not simply exposure to light that can alter the natural circadian rhythm, but also the wavelength of light that can be detrimental.

The Influence Of Light Wavelength

The visible light spectrum runs from 380nm to 780nm, with each nanometer representing a wavelength of light. At the high end of the spectrum (closer to 700) you find red light, and as you move through the rainbow of visible colors, the wavelength becomes shorter and shorter, ending with blue/violet light. Blue light is at its strongest in the morning and during daylight hours. This occurs because sunlight contains all the wavelengths of visible light, but since blue light is shorter, it is scattered more easily.

Blue light – found at 460-480 nm in wavelength – will suppress the biosynthesis of melatonin and keep us feeling alert. Interestingly, beyond 530nm melatonin production is not suppressed, even in bright light conditions.

In the early morning or late evening (sunrise and sunset), the sun is much lower on the horizon and therefore the light must pass through more particles to reach your eyes. This means that much of the blue light is lost before it reaches your eyes, and only long-wavelength red light is left to reach you. This influx of red light triggers your body to begin to produce melatonin so you can stay synced with the day/night cycle and begin to feel tired. Unfortunately, many artificial lights work against this natural cycle, emitting blue light in wavelengths that can suppress melatonin production, and therefore keep us feeling alert longer than it should. Prolonged exposure can shift our circadian rhythm out of its natural cycle.

A Harvard study found that after 6.5 hours of blue light exposure, melatonin was suppressed twice as long as when exposed to the green light for the same period. Circadian rhythms were also shifted 3 hours with blue light and 1.5 hours with the green light. When you consider the prevalence of blue-light emitting LED screens in the hours running up to sleep, it’s easy to see how you can shift your rhythm without realizing it – until it’s too late and your cycle has been damaged.

The biggest factor contributing to your circadian rhythm is light. However, it ’s extremely important to understand that lighting characteristics affecting your circadian rhythm can be different than those affecting your ability to see.  For example, the light that enables sight could also be used to signal your circadian rhythm that it is evening.

The people most likely to have out-of-sync circadian rhythms are those that spend a lot of time indoors and under dim light for extended periods of time. This environment is common with office workers and puts these individuals who work long hours indoors without windows to allow natural light into the room at high-risk for circadian rhythm damage.

Dr. Mariana Figueiro, professor and director at Lighting Research Center at Rensselaer Polytechnic Institute has been researching and educating people on how to synchronize their circadian rhythms for years. She describes Circadian Rhythm as a “blue sky” (short wavelength) detector.  Figueriro uses a great example related to camping that illustrates this concept:

Our pre-artificial light ancestors were in daylight first thing in the morning and shrouded in darkness after sunset, naturally syncing their Circadian Rhythms with the solar day. Based on this, Figueiro suggests that if you have ever been camping, you will probably begin to wake up with the sunrise and fall asleep with the sunset after only a couple of days in this sun-cycle.

Most of us now work and live comfortably inside, alongside constant artificial lighting instead of the cyclical nature of sunlight.  This non-stop, artificial light is one reason why two-thirds of us report disrupted sleep and ongoing sleep disorders.  Staying up after dark probably means that you are exposed to even more artificial light, only compounding the disruption to your Circadian Rhythm.

The Treatment of Circadian Rhythm Disorders

Luckily, most circadian rhythm disorders are treatable.

Dr. Figueiro and the LRC have developed the Circadian Stimulus (CS) metric to quantify light’s effect on the human circadian rhythm system. The team describes CS as a metric based on the extent to which a given light source – of specific amount and spectrum – suppresses Melatonin. The following light-related metrics, measured with CS, can help determine the source of sleep disturbance, and lead to a solution for treating sleep issues:

  1. Spectrum – Specific correlated color temperature (CCT) or wavelength of the light
  2. Light Levels – Proximity of light in relation to your eyes
  3. Timing – Time of day when you are receiving specific CCTs
  4. Duration – Length of time receiving specific CCTs

As Figueriro and the team’s study suggests, the higher each of these four metrics is, the more likely one is to experience issues. The increased amount and higher spectrum of light exhibited by frequent, extended exposure to artificial light sources can lead to disrupted circadian rhythms and an increased risk of rhythm-related sleep disorders. By implementing restrictions on this type and source of lighting in the times of the day that our bodies are naturally built to begin emitting melatonin, we can retrain our bodies to return to a natural cycle.

The Negative Effects of Sleep Disorder (Misaligned Circadian Rhythm Disorder)

Weight Gain

Weight gain has been associated with a lack of sleep for a number of reasons.

First, you’re more likely to make less healthy choices when you’re low on energy. For example, if you didn’t get enough sleep the night before, the first thing you’re likely to do is to load up on caffeine and carbohydrates to gain quick energy. This may be in the form of a simple cup of coffee or several of your favorite lattes. It’s also harder to resist sugary snacks such as donuts because you know they’ll give you a burst of energy from the sugar rush.

Second, if you’re already feeling tired, it’s unlikely you’ll be heading to the gym for a workout. Instead, you’ll want to go home and curl up in front of the TV. Exhaustion related to sleep-disorders can lead to poor health decisions that continue to damage the body.

Impulse Control

Sleep deprivation also impacts your impulse control. A study published in the American Journal of Clinical Nutrition found that when people experienced sleep deprivation, their late-night snacking increased and they were more likely to choose high-carb snacks for a quick-fix. You’re more likely to choose these unhealthy options because your body is looking for a boost of energy.

Impaired Brain Function

You may be surprised to learn that sleep deprivation affects the brain at a cellular level. A study published in Nature Medicine found that a lack of quality sleep makes it more difficult for brain cells to communicate with each other. This will result in increased mental lapses and impaired memory recall.

You’ve likely experienced this impaired mental state when sleep-deprived. In these moments,  you start struggling to focus and concentrate on a task because your mind is “foggy”. If you’re routinely finding it difficult to concentrate during the day, take a look at your sleep habits and make sure you’re getting enough rest at night.

Weakened Immune Function

Sleep is very important for a proper immune system function. When you sleep, your immune system produces proteins called cytokines. Cytokines are directly involved in the process of targeting infection and inflammation in your body. A lack of sleep also results in fewer antibodies in your system to fight off illnesses.  Proper lighting is critical for assisted living facilities where seniors are already more susceptible to health issues, and have trouble sleeping due to constantly on lighting.

If you’ve been looking for a natural way to boost your immune function and reduce your risk of illness, getting the recommended seven to nine hours of sleep every night is a great place to start.

Reduced Athletic Performance

Sleep is crucial to successful athletic performance. You may have heard people compare being sleep-deprived exhibiting the symptoms related to being drunk on alcohol. When it comes to your ability to react to certain situations quickly, proper sleep is vital.

You may have your doubts about this comparison, but according to the Centers for Disease Control and Prevention, being awake for 24 hours straight is comparable to having a blood alcohol content of 0.10% – a level higher than the legal driving limit. You may not be routinely staying up 24 hours straight, but if you’re repeatedly getting five to six hours of sleep every night (or if your child is often staying up late), your athletic ability may be impaired, and you will begin to feel increasingly impaired.

Steps to Improve

The simple act of resting for eight hours every night has the power to improve your overall health and wellness in ways you might not believe. It’s time to stop neglecting sleep and instead take advantage of its healing properties to live your healthiest, most productive daily life. If you struggle to get the recommended seven to nine hours of sleep every night, it’s time to switch up your routine and try some new techniques for rest. Consider the following for your new sleep lifestyle:

Avoid Caffeine

The smell of freshly brewed coffee first thing in the morning is invigorating and a welcome start to the day. The problem with coffee, however, is that people rarely limit it to the morning. Often, the cups will continue to flow throughout the day as energy levels dip. The caffeine found in coffee is a strong stimulant and most people aren’t aware of how long it actually stays in their system. Caffeine can remain active in your body for 10 to 14 hours. This means if you drink a cup of coffee at 4 p.m. to help you finish a final report, the caffeine won’t dissipate from your system until at least 2 a.m.! If you’re looking for a better night of sleep, start by cutting off your caffeine intake before noon to allow your body to transition naturally to the rest and sleep states of the day.

Remember, avoiding caffeine doesn’t just include coffee! Any caffeine source counts. Energy drinks, certain teas, and soda should all be avoided to limit your caffeine consumption late in the day.

Create The Right Sleep Environment

If you really want to revamp your sleep routine, it’s time to take distractions out of the bedroom. Start by removing the TV, as well as other gadgets that may be capturing your attention at night when you’re trying to fall asleep.

While you are at it, this also a great time to get a new mattress or pillow if you’ve been noticing any neck or back pain after you get up in the morning. Having a comfortable place to rest makes it a lot easier to fall asleep, and you’ll look forward to bedtime more if you know your mattress isn’t going to be squeaking with each movement. You will wake up refreshed and ready for a new day with these small steps in the right direction.

Exposure to the Correct CCT at the Correct time.

As we read above, sunlight exposure is very important for regulating your sleep patterns. You should be getting, at the very minimum, 30 minutes of sunlight exposure each day. Consider getting outside more if you’ve been sleeping poorly.

Admittedly, sunlight exposure is not always possible. You may work in a school or office building that doesn’t have many windows that let in natural light, or your work schedule may have you up at night and sleeping during the day.

In these cases, it can be helpful to look into a hue-correcting light that mimics the natural wavelength of sunlight for you! Using this kind of artificial light can help keep your circadian rhythms on schedule by creating the sun’s day-night cycle – even if you’re not getting outside in the sun as often as you like.

Sound impossible? Not anymore. The team at LEDdynamics has created a product that is perfect for people who regularly find themselves inside all day. The PERFEKTLIGHT technology, recently recognized by the IES, replicates the changes in light temperature and intensity as the sun travels across the sky. LEDdynamics has also managed to perfect the coloring tuning between two color temperatures. Often, when you tune between two colors you end up with a visible hue error, which can be distracting for people sensitive to light differences.  With PERFEKTLIGHT, you don’t have to worry about a hue error. Instead, you can reap the circadian sleep benefits that come with using a lighting fixture that mimics the sun!

If you are suffering from any amount of circadian rhythm-related sleep disorders, or simply want to experience the benefits of living your daily life with the natural cycle of light, its time to bring the PERFEKTLIGHT into your world! With PERFEKTLIGHT, you can ditch your sleep-disrupting artificial light and reclaim the energy and sleep your body is hungry for.

Click the following link for an in-depth article on PERFEKTLIGHT, or contact us now.

Guide to Tunable White LED Lighting

All-In-One Guide To Tunable White LED Lighting

Tunable White LED Bulb & Strip

According to the US Office of Energy Efficiency and Renewable Energy, white tunable lighting is “the ability to control a light source’s color temperature output.” Manufacturers have achieved this innovation by combining LEDs of different color temperatures into single bulbs or strips. By controlling the LEDs inside the bulb or on the strip, you can then shift (or “tune”) the color temperature within a fixture. This may sound like a simple feature on its surface, but it is in reality a game-changer for many industries and environments – and, as we will see, perhaps even for all people everywhere.

Tunable white LED lighting is a groundbreaking type of lighting that technically combines multiple lighting sources. Without these multiple sources, the shifting or tuning that we are describing would be impossible. It is only through specific changes, turning off one LED and turning on another, that we can achieve the incredible effects for which this type of lighting has become known. A marvel of both engineering and human psychology, tunable white LED lighting promises to change the world in a significant way – to a degree that no other type of lighting has since the first incandescent lightbulbs appeared on the market in the 19th century.

Tunable White LED Linear Pendant Light

Unlike any other type of lighting, tunable white LED lighting connects directly to our minds, not physically but conceptually. Because we can shift the color temperature in a tunable white LED lighting fixture, we can optimize it according to the environment or even according to the time of day. That way, we can align the light with our circadian rhythm to better match the gradual dimming effect that humans experienced for eons living in the wild, underneath the sun during the day and underneath the moon at night. Gone are the days of glaring, overwhelming lightbulbs, their insistence on shining the same bright beams down on people regardless of appropriateness, impossible to control.

We can think of tunable white LED lighting as “custom temperature lighting.” This is not custom in the sense that we need to personalize it in the factory, though. This is custom in the sense that we can personalize it on the fly, making changes as we need to make them, lowering or raising the color temperature according to our moods, whims, and desires. We need no better reason than “I want the light to be different” to reach for our tunable white LED lighting controller and then press a button or turn a knob, however our system happens to receive our input. This is lighting that is ushering in a new and unprecedented level of convenience and control.

Correlated Color Temperature Graph

To measure the white light produced via tunable white LED lighting, we use color correlated temperature (CCT). CCT figures correspond to our real-world experiences of lighting, and we measure them in degrees Kelvin. To give you an idea of what CCT means, consider the measurements 1,800 Kelvin and 7,000 Kelvin: the former corresponds to candlelight and the latter corresponds to daylight. When you see a tunable white LED lighting system that features a range within two CCTs, it means that the lighting can run between those two CCTs – and perhaps along them as well, hitting infinite possible CCTs. One key point to remember is that the higher the CCT in Kelvin, the “cooler” white it will yield, emitting a bluish white (the “coolest” white) at the highest CCT in Kelvin.

As researchers at Rensselaer Polytechnic Institute put it, CCT is “simpler to communicate than chromaticity or SPD, leading the lighting industry to accept CCT as a shorthand means of reporting the color appearance of ‘white’ light emitted from electric light sources.” This is just a straightforward way for us to talk about what we are perceiving when we look at a source of white light.

Human Centric Lighting in Office Space

Mark Halper at LEDs Magazine refers to tunable white LED lighting as “human-centric lighting,” and in recent years, this term has caught on throughout the industry. We will examine in greater detail the reasons this term fits what we can also call tunable white LED lighting. You already know, however, that tunable white LED lighting can match the human circadian rhythm, and this is an elucidating point. You can learn more about circadian rhythm in this article, which discusses how inextricable it is for overall health and wellness. Once we understand how tunable white LED lighting meshes with what we naturally expect and desire from our lighting sources, the rest of its benefits starts to make much more sense.

In addition to tunable white LED lighting and human-centric lighting, this type of lighting goes by a variety of names. Another is “dim to warm lighting.” This term states in the least-assuming way possible what the lighting type is accomplishing, moving from a dim color temperature upward to a higher one, its color temperature not fixed, a major step away from every other type of lighting that the market had seen previously.

Yet another term for tunable white LED lighting is “full-color tuning,” which refers to the capacity of the lighting type to emit light that captures the breadth of color temperature. Even more complimentary than “dim to warm lighting,” this term expresses the choice that has made it so captivating for people who are tired of purchasing lighting fixtures only to become dissatisfied with their color temperatures a short while later (and find themselves stuck with it, totally lacking control).

Whatever we call tunable white LED lighting, the most critical idea for us to realize is how drastically it differs from all other lighting types. Everything it accomplishes, it is the first lighting type to do so. Next, we are going to review how tunable white LED lighting accomplishes what it does – through the blending process.

The Blending Process

There is no way to understand tunable white LED lighting without first understanding how blending works. The process, in this case, is inseparable from the technology. To fulfill its purpose, tunable white LED lighting must combine the outputs of multiple LEDs. By following algorithms to shift from one CCT to another, the highest-quality tunable white LED lighting systems will mix multiple white light outputs – merging channels that are all producing white light at different color temperatures, from the very warm all the way to the very cool.

In their overview of tunable white LED lighting, the US Office of Energy Efficiency and Renewable Energy called controls “a critical element in white-tuning systems.” This, however, is an understatement. Tunable white LED lighting is inseparable from its controls: without its controls, the “tunable” part of the name would cease to apply.

Using the right controls – which may function via wireless Zigbee, Wifi, Bluetooth, or other signals – we direct the blending process to achieve the CCT that we intend. While more primitive systems struggled to maintain consistency in color temperature, modern tunable white LED lighting has adopted real-time feedback systems that combat the color shifting that takes away from the overall output quality.

To comprehend what differentiates one tunable white lighting system from another, we can look at the concept of linear tuning, which is the most common. This type of tuning is a detriment to CCT, its linearity pushing CCT away from the curve of the blackbody, which is something that absorbs all the light around it. Doing so, it leads to inaccurate CCT that is not along the curve of the blackbody – marring the light with a pink hue error. It was only recently that technology for non-linear tuning became feasible, its multi-color LEDs remaining outside most budgets.

At LEDynamics, we believe the most elegant non-linear white tuning solution involves an algorithm that combines pointed and precise amounts of green light, causing CCT to shift along the curve of the blackbody in a nonlinear movement, eliminating the hue error inherent to linear tuning.  More on this later.

Where Tunable White LED Lighting Fits

LEDdynamics Circadian Rhythm Lighting Icon

Tunable white LED lighting is, of course, much more than a trend or a novelty. This is lighting that can make life better for people. We have discussed how tunable white LED lighting can adhere to the human circadian rhythm to a degree that no other lighting can. This may sound intriguing in theory, but what does it mean in the real world? When we say that tunable white LED lighting is “human-centric lighting,” what are we talking about? It is undeniably interesting that we can change the color temperature of a light. We may even find ourselves thinking Wow, how far science and engineering have come. Now, let’s look more closely at what these advances mean for the world.

To understand why tunable white LED lighting has shown such immense promise, we only need to consider its potential effects. This lighting can adapt to people’s moods, responding to the shifts that people need to experience to feel comfortable in any environment, raising or lowering the color temperature in such a way that people’s mental health will benefit. It can also adapt to interior styles, expressing ideas and emotions in an environment, immersing people in these ideas and emotions and heightening the impact that the space has on people.

Tunable warm-white LED Classroom LightingTunable White LED Classroom LightingOne study out of the Pacific Northwest National Laboratory reported that within an elementary-school classroom in Fulsom, California, students performed better when they were doing their schoolwork under tunable white LED lighting. The Department of Energy had funded the study to analyze the cost savings they could expect by installing such lighting on a large scale. As striking as their findings about the savings were – amounting to costs that were somewhere between 48% and 69% lower – their findings about academic success were even more inspiring, conjuring up images of students nationwide studying and thriving under tunable white LED lighting in the school years ahead.

Tunable White LED Light in Jewelry Store Tunable White LED Light in Retail Store

Another study exhibited the usefulness of tunable white LED lighting in retail, where the lighting boosted sales. Time and again, researchers have concluded that tunable white LED lighting is simply preferable. This is lighting that people appreciate and that they feel comfortable around. Because diamonds appear most attractive under cooler color temperatures but other metals and colored stones appear more attractive under warmer color temperatures, jewelers can optimize their sales processes through tunable white lighting – or even apply white light to white surfaces for even more stunningly minimalist appearance.

Because tunable white LED lighting can improve people’s moods, it fits anywhere that people’s moods come into play. Retail environments, schools, and healthcare settings are the most obvious places where tunable white LED lighting would serve clear and immediate purposes, but in offices too, tunable white LED lighting is making a difference – not only helping people to feel happier and more comfortable but also enhancing productivity levels across teams, motivating people to work harder and to think more creatively.

This incredible lighting type also seems capable of shifting people’s perceptions of actual temperature. Conceivably, businesses in Minnesota could install tunable white LED lighting and change the color temperature in January to instill a perception of warmth. Businesses in Florida, meanwhile, could install tunable white LED lighting and change the color temperature to instill a perception of relief from the overbearing hot outside.

The entire atmosphere within any environment is malleable, all thanks to tunable white LED lighting. You can decide what you want people in an environment – or just yourself – to feel or think, implementing tunable white LED lighting as a tool to push perceptions in the right direction.  Tunable white lighting can prevent post lighting installation issues that may arise, when customers decide that the project feels too cool or too warm. Thanks to tunable white lighting, the color temperature is no longer permanent once the fixtures are installed. Planning and execution often falling into disconnect between one another, this level of control allows people to change their minds – say switching from a black granite table (which would look best under a cool color temperature) to a dark wood table (which would look best under a warm color temperature).

In the near future, it seems likely that tunable white LED lighting will become the lighting type of choice, for those who recognize its value at least. It only makes sense that hospitals, offices, schools, and other sensitive environments will install tunable white LED lighting en masse once the word is out. For many professionals and experts in the lighting field, this remains something of an open secret, the inventiveness and the undeniable value of tunable white LED lighting constantly on display for all to see but still remaining just out of conscious view for people who have not heard of it or who have not gone looking for it on their own.

Think of it as a club, and now you are a part of it.


LEDdynamics Logo

A Clear Choice

Color Tuning in Smartphones

Never before has a lighting innovation coalesced so well with what people need out of their lights. Long before we knew it, traditional lighting was disrupting our circadian rhythm, and for many urban dwellers, a good night’s sleep remains ever-elusive because of the bright incandescent lights that pour through their windows at all hours. Think about the popular image of the insomniac unable to escape the ever-present glow of the brightly-lit billboard outside her window. This is an extreme example, of course, but it illustrates the effect that lighting can have on our lives. We crave lighting that aligns with our moods and desires.

Other types of lighting feature two modes – on and off. Through the most advanced tunable white LED lighting systems, there are infinite modes, all of the degrees of color temperature within the color temperature range of which each system is capable. Whatever you want out of your space, however you want your lighting to make you feel, it is possible. Wake up to the softest trickle of light, like the gently rising sun. Do your work beneath something a little bit cooler and a little brighter.

Tunable white LED lighting is poised to fundamentally alter our relationship with lighting. We are looking beyond the “on/off” switch and thinking about everything we have ever wanted lighting to be. If you have dreamed about a lighting system that accounted for your vision within your home, office, restaurant, classroom, hotel, or retail location, tunable white LED lighting is for you. The future of lighting is unfolding before your eyes – gradually, of course, and ever so gently – and you are welcome to take it in and then take control of it at your leisure.

This is the lighting type that we have all been waiting for. For everyone who has ever thought that something better must be possible, we want to tell you – it is. We want to state in no uncertain terms that tunable white LED lighting is different.

This is the cutting edge of lighting, and our team at LEDdynamics is working on the cutting edge of that – the cutting edge of the cutting edge. We are the first lighting manufacturer to create a non-linear tunable white lighting solution that uses green correction, and we want to show you what a difference it can make. This is a thrilling innovation. We have invested in it heavily, and we remain focused on it, confident that this is the next great frontier in lighting. Changing spaces worldwide, we are proud to stand up as pioneers in human-centric lighting.

To learn more about tunable white LED lighting and how our team at LEDdynamics is putting it into action please contact us here


LEDdynamics’ PERFEKTLIGHT™ Technology Tunes & Corrects White Light

Color Tuning in SmartphonesThe popularity of tunable white LED lighting is a lasting trend. Aside from its obvious improvements for lighting options, it also stands to make a positive impact on our overall health and well-being. Specifically, studies on Circadian Rhythm are proving how important the timing of specific correlated color temperatures (CCT) are during a daily cycle, from aiding hormone release, influencing digestion, maintaining body temperature, supporting healthy sleep patterns, and other key bodily functions.

This technology has already found its way into smartphones, tablets, and computers. For instance, Apple and Android have implemented a night shift mode from sunset to sunrise. This mode allows the phone’s screen to mute a lot of its blue tones throughout the evening and early morning.

This reliance on artificial light has not always been typical.

Over the past three hundred thousand years, humans have evolved under natural daylight. Waking up in the morning and seeing that warm (2,700K) sunrise and 6,500K (cool-white) as the day progresses towards noon, where CCT peaks. As time moves towards the afternoon and evening, the color temperature decreases back down to around 2,700K again (illustrated in the daily sunlight cycle pictured below).

Daily Sunlight Cycle

This color shift is the result of the sunlight traveling through more of the earth’s atmosphere in the morning and evening, which causes the blue light to scatter. This is why we see those nice reds and oranges seen through sunrise and sunset. The blue light is not as scattered because it travels through less of the earth’s atmosphere in the middle of day, producing a higher “bluish” color temperature.

PERFEKTLIGHT can replicate this change automatically with “PERFEKT” CCT.
Comparatively, it has been a fairly short period of time that humans have been living and working under artificial illumination. Figure A and B, in the image below is a spectral power distribution graph of sunlight. It is a pretty good representation of light from all the visible spectrums. As you can see, sunrise and sunset have very muted violets, blues, and greens and a lot of reds and red-oranges.

Incandescent bulbs, figure D, are a good representation of sunrise and sunset but do a poor job matching sunlight CCT throughout the remaining parts of the day.

Additionally, the LED bulbs do not match any of the spectral graphs. Figure C graphs a typical 5,000K (cool-white) 80min Color Rendering Index (CRI) part that is prevalent in many of the products available in the marketplace today.  The large blue spike has significant consequences for tunable white LED systems trying to produce circadian lighting.

Spectral Power Distribution Graphs

Figures A, B, C & D from Left-to-Right

PERFEKTLIGHT is very different from all other light sources. 

Pictured below is the spectral distribution of PERFEKTLIGHT. At 2,700K, it has muted blues and lots of the reds, red orange, and ambers typically experienced in the sunlight. As the color temperature increases on the diagram, traveling from the left-hand side to the right-hand side, the blue increases. PERFEKTLIGHT at about 6,500K is almost an exact spectral distribution match of sunlight; there is a nice even balance of blues all the way up to the reds..PERFEKTLIGHT Spectral Power Distribution Graphs

Artificial sunlight with LEDs is made possible with the latest Nichia LED technology and LEDynamics patent pending PEFEKTLIGHT technology. CRI is typically 95 or greater and CCT is directly on the Blackbody line (BBL).

Black Body Curve

Blackbody Line or Plankian Locus

The Blackbody line (BBL) is based on the color a dark iron metal typically glows when heated up to that temperature. When you heat a chunk of iron up to 2,700K, it glows that nice red-orange and amber color, seen from incandescent bulbs. As this chunk of iron gets hotter the color temperature goes from that red-orange and amber, up to a neutral-white. As it continues up to 6500k, the bluish-white tone shows-up.

This is relevant because LED binning is defined around the BBL. In figure E below, the BBL has ANSI-defined boxes; ANSI is defined by eight color bands. Within those ANSI defined boxes there can be roughly five-step MacAdam ellipse and smaller three-step MacAdam ellipse. LED manufacturers are doing their best to put LEDs right on the BBL. In some instances, two steps are available and in rare cases, some LED manufacturers can even produce one step.

Figure E – ANSI & MacAdam Ellipse on Blackbody Curve

Typical tunable white LED systems mix two LEDs with opposite color temperatures.  In the graph below you can see a 2,700K LED in the upper right and a 6,500K LED in the lower left.  The 2,700K LED measures in at about a three-step MacAdam ellipse.  On the other hand, the 6,500K LED, even though it is a three-step part, turned out to be right on the BBL.

Tuning between the two colors creates CCT in a straight light between the two LEDs; illustrated by the purple line in Figure F below.  The hue error is between the purple line and the BBL.  In the middle of that straight line is where the delta between the BBL is the greatest.  The hue error around 4,000K is outside of the seventh step MacAdam ellipse.  Anybody looking at that would be able to tell there is something not quite right with that lighting.

PERFEKTLIGHT CCT Graph without Correction

Figure F – Illustrating Hue Error without PERFEKTLIGHT correction

This is what PERFEKTLIGHT corrects!

Zachary Treamer, LEDdynamics Director of Product Marketing says, “PERFEKTLIGHT™ technology, recognized by the IES 2020 progress report, color corrects tunable white light; eliminating hue error seen when tuning from warm correlated color temperate (CCT) to cool.  Its patent-pending hue correction technology conveniently pairs with “set-it & forget-it” controls to mimic sunlight CCT & CRI from sunrise to sunset and maintain even light across the whole CCT range.  Lux or foot candles measured on a surface at 2,700K are going to be the same as 6,500K (Figure G).”

Even Light Output Across CCT

Figure G – PERFEKTLIGHT Maintains Even Light Across the Whole CCT Range

The green line on the graph below shows the CCT with the PERFEKTLIGHT correction.

PERFEKTLIGHT CCT Graph with Correction

Figure H

Treamer continues, “PERFEKTLIGHT corrects that hue error by filling the External Quantom Efficiency green gap (Figure H).  PERFEKTLIGHT is able to correct that hue error as the white is tuned along the whole CCT; keeping the light CCT directly on the BBL as desired.”

LEDdynamics CEO, Neil Cannon, adds “Tunable white had long-standing issues.  Our aim with PERFEKTLIGHT was not to get close to sunlight, but to exactly match it.  Now, sunlight can be brought indoors with controls to synchronize the interior lighting with what is happening outside throughout the day.  This has the added benefit of minimizing the disruption to our circadian rhythm.”

Prolume did the first installation of PERFEKTLIGHT in Randolph, VT at Chefs Market.  LEDdynamics designed LED modules to retrofit their pendant style light fixtures.  There is a great picture below, showing the historic building that has been renovated into an organic grocer as well as a fantastic restaurant.

The pictures show the retrofitted pendants, and if you look closely, there are three pendants in the center picture.  If you draw your attention to the pendant in front of one of the many windows (we recommend the one furthest way), it shows how the color temperature of the light coming into the window and the color temperature of the pendant are perfectly matched.

The feedback received from the owners of Chef’s Market, as well as the employees and the community, has been overwhelmingly positive.  The owners report the lighting has caused an increase in sales as more consumers wish to be there, and even employees say they are feeling more energized at work and able to fall asleep better in the evening.

PERFEKTLIGHT Installation at Chef's Market

PERFEKTLIGHT is the ideal solution for Human Centric Lighting and the health lighting market.

LEDdynamics will provide the highest possible quality of light using the latest technology, in the hopes that by bringing the outside lighting to the indoors, the disruption to circadian rhythms will be decreased. As science has proven, this will have the added benefit of enhancing sleep cycle and other necessary health impacts on the body.

Studies have shown that adjusting the color temperature at various points in the day for students at school also enhances their productivity, a realization that can be extrapolated to enhancing productivity for any artificial illuminated environment.

The schedule is set by a real-time clock with “set-it and forget-it” electronics, which allow the whole system to integrate with the existing controls.  It does not require any sophisticated set-up.  The real-time clock and “set-it and forget-it” control electronics make it work outside of the box.  PERFEKTLIGHT is also compatible with third-party controls if required.

When PERFEKTLIGHT was first theorized by LEDdynamics CTO, William McGrath, it struck excitement amongst the team.  “Only after testing the hypothesis did the excitement turn into a reality for us,” said Mr. McGrath.  “In some cases, seeing is believing.  This is one of those cases,” McGrath, concluded.

A portable PERFEKTLIGHT demonstration kit is available.  LEDdynamics sales team would love the opportunity to present this technology further.  Please take a look at the main PERFEKTLIGHT webpage for more info or contact us beleow:

Please contact us about PERFEKTLIGHT.

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