How to distinguish the high quality phototherapy lamp!

There are so many kinds of phototherapy lamps on the market, the difference of their price are relatively large, but the advertising is just similar, how to select? let's talk step by step:

1. Workmanship, Shape and Color: We can feel it by pictures, vedio, and even eyes and touch directly.

2. Function: the more, the better, but stable and easy to use. Now some therapy light take the alarm clock with sunrise and sunset simulation, adjustable brightness and color temperature, Rechargeable. which can also be used as a "wake-up light". such as this one:  New Wake-up Light Therapy Lamp

But the more features, the higher cost, we only choose what suits us best,

3. The materials. We can distinguish the quality of shell and accessories such as adapter, print and design of instruction, even the package. From the details, we can feel if the seller make products with heart and spirit by our eyes and touch directly, but the electronic material need time to be certified. The most important material is light source. One is traditional halogen light, (over 100W, big
size, expensive, rare, not environmental protection), another one is LED. (10-30W, small size, High cost performance, common).

The therapy light should use the genuine full spectrum, uv-free LED, I use the "genuine" to describe, why? because a large part of suppliers use normal led as full spectrum led, but they falsely allege that they use the "full spectrum led". 

What’s "full spectrum led" ? and How to distinguish

A light that produces 10,000 lux of full spectrum light is an effective treatment for
light therapy.

In terms of light quality and full spectrum light; a lot of units on the market produce one color of light such as a blue color or even a yellow color of light. Exposing your eyes to one color of light for a prolonged period of time can be very harmful. Full spectrum light is the best quality of light for your eye because your photo receptors are designed for the color and clarity of sunlight (or full spectrum light).

A lot of companies advertise their products using terms such as “ day light ” , “natural spectrum”, “broad spectrum”, “sunlight”, and “full spectrum” to
market their products as something that is more like the quality of light that sunlight produces but they do not meet the minimum requirement of a full spectrum light. In order to be considered full spectrum the color temperature (Kelvin) should be between 5,000 and 6,000 Kelvin; as mid-day sun is 5900K. Full spectrum light also has a CRI (e), [not CRI(Ra)], of at least 90. Sunlight on a sunny day around noon has a CRI of 100 CRI. Of the wide variety of light therapy products on the market today, only our Lukirch light therapy lamps from Full Spectrum Solutions provide the benefit of the most natural light technology available today and produce a Kelvin of 6000 and a CRI(e) of 95. Using innovations developed by the firm’s researchers, our bulbs more closely replicate the sun than any other lighting products ever manufactured. Our
therapy provide the best color (kelvin) and clarity (CRI) ratings in the industry with the closest match to daylight, which means the best quality of light for your eyes.

But How to distinguish?

1. By feeling. If you look at light or reading something under this light, your eyes
don't feel well after a while, even can't stand it, there's no doubt that it's not a good quality, full spectrum led.

2. By measuring CRI (Color Rendering Index), if the CRI (Ra) < 90, it is not "full
spectrum LED" definitely, but if CRI (Ra)>90, it is not necessarily full spectrum LED. If CRI (e)>90 or 95, it is extended CRI (R1-R14), the led quality will be superior. Let’s know CRI firstly. Our CRI (R1-R14)>95! 

When comparing lighting products, you will undoubtedly come across the metrics CRI and Ra to describe color quality. You may assume that there is no difference between CRI vs Ra, but read on to find out how this could be a mistake!

CRI defined

CRI is an acronym for Color Rendering Index, and is the world's most widely accepted metric to describe a light source's ability to accurately reproduce color.
The general concept involves using a set of 15 predefined colors called test color samples (TCS) and determining how accurate a light source would make each of these colors appear.

"Accurate" is defined as similarity to natural daylight or an incandescent bulb,
depending on its color temperature. (This is a bit of a simplification - for detail, see here). Each of these TCS scores is called Ri, where R stands for Rendering Score, and i is the TCS index number. For example, the score for TCS4 ("Moderate yellowish green") would be calculated and labeled as R4. Once each of the R values is calculated, two types of CRI, called General CRI and Extended CRI, can be calculated.

One is General CRI

General CRI is calculated as the average value of R1 through R8. Formulaically, this is often referred to as Ra, where a is an abbreviation for "average." Note that only R1 through R8 are used, and R9-R15 are NOT used in the calculation
of Ra

Another one is Extended CRI

Extended CRI is calculated as the average value of R1 through R14. Sometimes the symbol "Re" is used, where the letter "e" represents "extended." Notably, extended CRI captures the influence of saturated colors such as deep red
(R9) and strong blue (R12) that general CRI does not.

This is one of the criticisms of the general CRI, and it is therefore always a good idea to look at extended CRI and the specific R values when working on a project where color quality matters.

What is Ra?

Technically, Ra is just a symbol in the formulae for general CRI calculations, but has become widely used as a synonym for general CRI. In other words, Ra is also the average value of R1 through R8.

Lost in translation?

In the United States, the term CRI is used to refer to general CRI (R1-R8), while this is not necessarily the case in other regions of the world. In China and Europe, for example, CRI is typically used to describe extended CRI (R1-R14).

Depending on who you are speaking to, CRI can take on a very different meaning. Our recommendation is to be explicit when discussing these metrics with manufacturers and customers. When discussing general CRI, it is best to use the term "CRI (Ra)" or general CRI (R1-R8). When discussing extended CRI, use the term "CRI(e)", "Re" or extended CRI (R1-R14).

Typically, extended CRI is used less frequently than general CRI, but when in doubt, it is always best to clarify!

Myth #1: All therapy light that use full spectrum light emit harmful UV rays. Why this might sound plausible: Some lighting companies use the term ”full spectrum” to include the ultraviolet wavelengths. The Truth: The term “full spectrum” is a loosely-defined term, used differently by different companies within the lighting industry, but it always means light with a color temperature of at least 5,000? Kelvin. When using this term, some companies include the ultraviolet wavelengths, while others, such as the our Company, use it to mean the full visible part of the spectrum, which does not include the invisible UV wavelengths. Our full spectrum light boxes have an acrylic diffuser which eliminates UV wavelengths from being emitted (independent lab report available upon request).

Myth #2: If a SAD light that produces 10,000 lux gives results in 15-30 minutes per day, I can cut my treatment time in half by using a light box that produces 20,000 lux. Why this might sound plausible: Research has shown that for intensities between 2,500 lux and 10,000 lux, double the intensity generally equates to half the treatment time. The Truth: Intensities higher than 10,000 lux have not been studied for safety or efficacy. There is no clinical evidence that intensities higher than 10,000 lux are safe, so if the health of your eyes and your skin is at all important to you, you should carefully weigh the significant risks to your health of using untested technology for the sake of reclaiming a mere 10-15 minutes each day.

Myth #3: My doctor told me all I need to do is to replace all my existing light bulbs with full spectrum bulbs and that will alleviate my SAD symptoms. Why this might sound plausible: SAD appears when people are not exposed to enough environmental sunlight. Sunlight has an even color distribution, which full spectrum lighting comes close to replicating. The initial studies on light therapy for SAD used full spectrum light fixtures. The truth: The truth is that researchers have determined that lighting below 2,500 lux simply isn’t bright enough to affect brain chemistry to the degree necessary to allow for the alleviation of SAD symptoms. Most homes have lighting below 500 lux, and well-lit offices generally have light levels between 500-700 lux. Replacing the bulbs in your existing fixtures with full spectrum bulbs
does nothing to increase the light output; a 40-watt full spectrum fluorescent tube puts out the same amount of light as a 40-watt cool white fluorescent. Shop lights you’d get at your local hardware store or lighting store are designed to produce enough light to allow you to see what you’re doing, not enough to affect brain chemistry. For that, special light fixtures, designed for increased light output, are necessary.

Myth #4: The larger the light box, the more effective it is. Why this might sound
plausible: A larger light box will “bathe” you in a field of light, which gives the illusion of more light reaching you. The Truth: We are unaware of any clinical evidence that a large light box is any more effective than a smaller box producing the same brightness and used properly. While a larger light box allows you some freedom of movement while using it (you can move from side to side during your light session and receive the same intensity of light in either position), this could be a potential drawback: if you think you can change your position during your light session, you might move further from it or closer to it, or might move too far to either side, all of which will change the light levels reaching your eyes, resulting in inconsistent light exposure during the session.