Seoul Semiconductor has pre-released a series of LEDs it has claimed to produce near sun-like color and SPD at an impressive 97CRI. The marketing message is that this represents a breakthrough in delivering a more natural light to the eye, thus supporting improved health and well-being. Here is their claim, specifically:

SunLike fundamentally transforms LED lighting technology by removing the blue LED light source and replacing it with a purple light LED chip. Seoul Semiconductor is bringing the closest light to the sun to market. An ordinary LED spectrum is very different to sunlight, whereas SunLike’s spectrum is almost the same. Objects lit by SunLike appear as they would in sunlight.

Further, they also claim:

SunLike enables human-centric lighting optimized for circadian rhythms

And finally:

SunLike realizes high quality light

So, is it all that? Or, is this just another of a long and deep list of marketing campaigns making unsupportable claims?

Peeling the Marketing Farf Layer

The claim is that the Sunlike LED’s “spectrum is almost the same” as sunlight. This is accompanied by a colorful graphic that presents this case. For comparison purposes, I took that colorful graphic and overlaid the actual SPD of sunlight, as well as all three of the Sunlike LED SPDs, to expose how much of the image was marketing farf, and how much is actually real:

Overly of web graphic claim and actual SPD distributions for comparison (updated to correct error in daylight SPD representation)


Based on this, I would have to call the colorful web graphic as inaccurately distorted to make a product claim. On a scale of 1-10, with 1 being a complete lie and 10 being an accurate representation, I give the promotional graphic a 5 out of 10. It not only distorts the products SPD into something that does not actually exist, it distorts sunlight itself to make its claim. I suggest that it would be of value for SSC to revise the graphic to reduce the distortions that challenge its credibility.

Peeling the Sunlike vs. Conventional LED SPD Layer

The claim is that these new LEDs are superior to conventional LEDs, presenting a more complete spectrum with less blue light. To make this comparison, I extracted the SPDs of 5000K, 4000K and 5000K LEDs from Seoul’s own offering, and compared them to the new Sunlike SPDs as follows:

Comparison of Sunlike to Other LEDs

Based on this comparison, there are several conclusions one might draw. First, there is indeed a relative difference in blue light content, specifically at the 456nm peak. This is evident in all three CCT’s and represents a significant improvement. As a portion of total output, the Sunlike products produce a welcome improvement in both mitigating the over-production of blue light in the circadian sensitive 460nm region, but an overall improvement in filling the spectral gap between that peak and the rest of the spectral distribution. This is most apparent in the 5000K and 4000K sources. The difference at 3000K is less significant, but still evident.

The SPDs of the Sunlike LEDs appears to represent an improvement that will be seen in surfaces illuminated. While not exactly up to the task of duplicating daylight itself, these LEDs are certainly an improvement, and do represent “Seoul Semiconductor is bringing the closest light to the sun to market”. Although, there are other LEDs and LED products generating a similar improvement. For example, at 4000K and 3000K, the Xicato Artist modules in 3000K are close to the Sunlike product SPD:

Xicato Artist 3000K

And the Soraa 3000K LED comes close as well in 3000K, with its blue peak at 405nm, in stead of the 456nm, making it equally good for blue light mitigation.

Soraa 3000K 95CRI. Nore blue peak is at 405nm, not the normal 456nm.

However, at 4000K, the Xicato fall short of matching the SSC Sunlike SPD:

Xicato Designer 4000K

However, from the standpoint of mitigating ~460nm blue, at 4000K, Soraa does produce a reasonably good product at 95CRI:

Soraa 4000K 95CRI – note blue peak is at 405nm

Neither Soraa or Xicato offer anything in 5000K LED, nor does anyone else even close to the SPD of the SSC Sunlike product.

Based on this, and comparisons of several other LEDs not shown here, I would rate the claim that the Sunlike LEDs are a significant improvement over other available products a solid 8.5 out of 10, mainly due to the real advantage shown in the 5000K and 4000K CCTs. First, there are very few 5000K LEDs on the market with a high enough CRI to be considered viable. Second, the number of 4000K LEDs with high CRI’s are limited. I do not see a large advatnage to the Sunlike product at 3000K, as at this CCT, there are many options, all with limited blue light content, simply due to the need to down-convert as much of that light as possible to generate the warmer spectral power necessary. The small difference in blue peaks between high CRI 3000K LEDs and Sunlike is arguably marginal.

Peeling the Human Factors Layer

To be brief… While there is a reduction in balance between the 460nm peak that imparts melatonin suppression response, I do not believe that this alone will produce a real driving force in selecting these LEDs over any other. The entire issue of human factors lighting is far more complex that changing the SPD of light sources that are on continuously. As it is now known, circadian entrainment around the 460nm peak is affected mainly early in the day, for a brief period of time, which then shifts to red of around 620nm sometime mid-day. There is not evidence that tinkering with subtle difference in white light sources will have any long-term effect on human health. Illuminance levels, timing, available natural light, and other factors outside the realm of lighting itself play a role in this. In my opinion, the use of “Human Centric” wording has now become a marketing term, like the nearly obsolete “Green” propaganda, that eventually burned itself dry. For this, I give SSC a 2 of 10 for going down this road. I suggest this approach be dropped until there is objective supporting evidence that these products can actually deliver a real benefit.

Peeling the Qualities Layer

As I noted, the quality of light from this new generation of LED technology, with its re-balanced and fuller spectral power delivery, is going to produce higher light quality. The light from each of the CCTs will appear more neutrally “white” with less of the cyan or orange shifting exhibited by conventional blue pump LEDs. Similar to the improvement in light quality that Soraa and Xicato delivers in their high CRI products, for similar reasons, plus a little more, due to broader tails. The Sunlike 5000K LED is poised to be the most attractive high CCT LED on the market, by a fair margin, with far less distortion of reds and greens, and less harshness overall. On this I score these LEDs a solid 9.0 of 10.


In my opinion, the SPD’s produced by the Sunlike products is exactly the direction the entire LED universe needs to move toward. They are not perfect, but are far less flawed than most. The re-balancing of energy in the 460nm region downward into the longer wavelengths, the more complete SPD, and shift of some blue upward into the 405nm region – are all very good things. These LEDs will generate more precise color rendition with less of the harshness and flatness that LEDs are frequently seen as producing. Further, the slightly more full and wider blue tail (400-55nm) of these LEDs at 3000K will go a long way toward reducing the artificially over-red-orange and pinky hue that make them appear less “white” than their idealistic halogen predecessors.

I suggest the most significant impact of the Sunlike products will be to present lighting customers 4000K and 5000K products that will be considered attractive, over the current range of products now in the market that feel harsh, cold and flat. The fuller spectrum, lower blue content, and flatter region between 500nm and 650nm are going to produce far better color appearance and fullness than what is on the market currently.

Overall, I give Seoul kudos for this product, and look forward to working with these LEDs  in more real-world applications.

When you spend a lot of time at the controls of word processors, spreadsheets, design software and 3D CAD, you may find that the pedestrian swill keyboards and mouse devices from the office supply and consumer electronics stores inadequate. I know I do. I used to go through a keyboard every year, and suffered from mouse fidelity issues (lack thereof). What I have found a superior approach is to using gaming interfaces. Gamers beat and pound away at their equipment, and subject them to real uses and abuses that office equipment is just not the equal of. Gamers also demand far more precision and consistent response. All good things for design uses.

The Keyboard

I beat the daylights out of keyboards. When you work with tools, you get used to exerting a certain amount of force in tool use. That means hitting keys a little harder than what soft handed office workers might exert. Meanwhile, I type a lot on any given day, frequently in excess of 4000 words. The wimpy blister switches under the keys of most keyboards are just not up to the task. They also have very little resistance to intrusion of dirt and grit that follows me in from the shop.

I also want to feel and hear the keyboard work, and not feel like some chintzy plastic thing creaking and clanking, as I put it through its paces. I’m an old school tactical feedback junkie.

So, after some time and several scrapped keyboards, I found Corsair Keyboards to be the top choice. Corsair makes keyboards for the whacked out gamers, who abuse their keys as much as I do. These are mechanical keyboards, which means they use actual individual switched under each key. These can be replaced if necessary, including swapping heavily used keys for others elsewhere on the board. You can get these in many different configurations. Options include different key stroke actuating distances, LED colors, key colors, etc.. The keyboard also includes a brushed, black anodized fascia, and the foundation is solid as a rock. The underpinnings of all the Corsair keyboards are generally the same, with a selection of key stroke lengths, and LED colors under lighting them. For my use, I don’t need a lot of the features they offer, so chose the K70Lux.

As an FYI, I don’t use wireless keyboards. The slight delay they impose, and the hassle of dead batteries is worse than dealing with a wire. Also, this is connected to an old school large format desktop machine, not a laptop. Lap tops have come a long way in power and processing speed, but are still not up to the same level as a good old box with standard size processors and memory cards cooled by fans.

A keyboard you can pound on. Perfect for responding to even the most aggravating internet troll!

The Mouse

The issue with mouse operation comes in three forms for me. The first is the fit in my hand. I need something that has a solid tactile feel to it that can be felt through bandages, burns, and callused finger tips. The second is tracking consistency, particularly when  using Illustrator or Solid Works, where the ability to hone in on one line or edge without having to play around with zooming in and out, is a real time saver. The problem is, office grade commodity mice have the resolution of less than the screen at 800dpi. The third is response time. Wireless mice are really neat-o toys, but for real CAD work, a wired mouse is still king. No delay time, no dead batteries in the middle of a project, and no changes in sensitivity to the tracking surface as the batteries fade.

Being happy with the Corsair keyboard, I dipped into the gamer well once more. Corsair mice are tough little critters. The Corsair M65, my personal choice, has an aluminum frame. There is also a weight system in the base that can be adjusted to change the way the device feels as it is moved around. It takes a little tinkering, but the result is worth it. An interesting bonus with the M65, is that you can get replacement Teflon glide pads for the base should they wear, rather than chucking the device into the trash.

The M65 resolution can be set as high as 12000dpi, so the issue of resolution is solved. There is also a “sniper” button on the thumb side of the device that changes the mouse response for this instances when you are trying to zero in on a tiny detail, or select a letter in a block of text, etc… The mouse is wired, so response time is instantaneous. Finally, the weight and the design of the device provides very strong tactile feel.

I also use a metal plate mouse pad, like those made by Alsop, as they wear well, and are easy to clean.

Who cares about building a better mousetrap, the hunt of a better mouse is far more important to me.

The Cost of it All

The performance of these interfaces eclipses all the junk I’ve dumpstered over the years from the office supply stores. The fact that these components actually carry a minimal premium was a bonus. While there are certainly $20 keyboards on millions of desks of unfortunate cubical drones, accompanied by $10 mice, I don’t consider those a legitimate baseline of comparison. CAD work demands more than what commodity mice provide. Regular writing work has been a matter of tactile interface that has caused writers to seek tools that fit them like an extension of their hands. From hand-made pens to typewriters, writers are a picky lot, and for good reason. If you feel good about the mechanical bits, the writing holds center stage, with less feeling of effort.

With that in mind, the cost of the pair of keyboard and mouse I use costs less than $170, tax included. Considering there are currently “ergonomic” mice on the market that cost more than the M65, and the number of $59 premium keyboards I have tossed, the return on this minimal investment is solid. The ability to repair the keyboard (although it does require some soldering skills) is a bonus, over just making more garbage to be dealt with in the waste stream.

So, while the only thing SSL about this product is the LED back-lighting used in the devices, I thought I’d share just the same. Cheers!

The AMA has stepped in to take the stand that warm color LEDs are the only products suitable for street lighting. For anyone interested in this, please read it before assuming you know what it says. There are several factual errors in this document. Most in the lighting design business will see them. The LRC has issued a response to this document.  The IES has also issued its own response.   Again, for those interested, read all of these documents before blowing a gasket and spewing conspiracy theories into the realm, deriding the IES, the LRC or the AMA. It is probably worthwhile also to include the recommendations and statements of the IDA (Dark Skies) as they are the ones who actually initiated the <3000K solution. Read the rest of this entry »

Product development and management has evolved from the days of taking a shot on a hunch. In the days of fabricating products with minimal tooling, the risk of failure was low, and profit reward for success quite good. Who needed product management? Design it, build it, catalog it and get it to the reps and wait for the orders to roll in.

The lighting industry also has a long history of operating with lean management structures, particularly in small organizations. Ownership, Marketing, Engineering, Finance, Design, Engineering, and Sales all have a role in product development, planning and line maintenance. How well product management tasks are accomplished is Read the rest of this entry »

The Mythical Imagery of an Irrelevant and Laggardly Lighting Designer Singularity

The scuttlebutt among select vocal SSL technologists and aggressive LED lighting marketeers derides the “Lighting Design” community as a singularity, and a lot of plonkers, that know nothing about technology, who are so focused on lighting surfaces they ignore the needs of human occupants. Some go as far as accusing Lighting Professionals of gross negligence and malpractice. A few others proffer a theory that conventional lamp manufacturers and their simple technology have propped designers up – that the emergence of LED has exposed them as technical posers, who know nothing of photo-metrics, glare, and visual comfort. Others point to statistics showing “Lighting Designers” are involved in just 5-10% of product decisions to prove them irrelevant. To these antagonists, it must seem a mystery how Lighting Designers have escaped exposure for so many years. Read the rest of this entry »

I’ve posted this sort of content before and will do so again. This is the sort of thing I cobble together from found objects, spare parts, experiments in fabrication, and other brain re-setting exercises.

My center all touch-stone and tribute to the mechanical arts that compete at the Bonneville Salt Flats every year.

This particular rat bike object “Schwinncomotor” started from a rusting Schwinn Collegiate 5 speed bicycle I found at a yard sale for less than the cost of a meal at Wendy’s, coupled with a love for land speed record motorcycles and the nutters that pilot them bravely down one of the worst surfaces one can imagine on two wheels at high-speed. This is primarily a sculpture intended to look as though it was just back from the salt, uncleaned and suffering the pit-side hacking and clever re-engineering that goes on when teams make the best of their time on the flats.  It actually runs and drives. Add a bit of oil and gas, give it a pedal and hang on. It will do around 40MPH for anyone brave enough. For me, it serves as a touch stone to the universe of mechanical simplicity, a respite from the magic smoke electronics that makes up daily life in the shop here. The “Gear Head” art above the bike is also mine, from a used up race kart sprocket and a hammered aluminum mask from a wrecked floor plate.

A salt flat inspired creation. The flat panel light represents the salt, where the glare and reflection will burn you in places you’ve never been burned before.

For those who like details, the bike is vintage 1972, made in USA, that has been cut, chopped, bent and stretched savagely to create the parallelogram angles and trapezoid tube layout. The motor is new from a kit, a whopping 63cc screaming 2-stroke piston valve power. The front fork suspension system is modified vintage 1958 welded to a Schwinn blade fork that was bent to suit. This bike has seen a lot of torching and welding, from fork stem and handlebars to rear stays. The rest of the bike is custom bits made from fiberglass, metal or 3D printing (intake horn is actually plastic, as is the front air piercing element). The “salt” patina is white rubber sealant that looks the part but doesn’t flake off even on the tires. The seat is a composite of three different seats and 3D printed parts. I made no attempt to create a finished show bike. In fact every effort was made to do this with minimal use of measuring tools or finishing finesse of any sort. More time was spent making it look used up and old than it might have taken making it pretty – but that’s how I roll on this one. It was never going to be a show bike, its foundation was too far gone for that. Unlike those who believe the rusting hulk with tree growing through them in their yards are one day going to be pristine show treasures… I respect patina and recognize when the time for restoration has long past. Respect the rat as it were.

How does it ride? Well… pretty awful actually. The rake and trail make the front end floppy at low-speed. The motor and drive-train make peddling a bit hard. The front fork, being designed and modified, is not the sharpest handling part I have encountered on a bike – tending to be a little wiggly at times. Once the motor starts (pretty easy) it is fun, as long as you keep speeds above 20MPH to get the front end to pull in line. Other than that… it’s a sculpture, and is at its best sitting perfectly still.

The “Internet of Things” has now become the newest, hottest marketing powerhouse. The scale of claims and the breadth of its application transcends lighting, so it eclipses popular lighting themes of Energy Efficiency and Human-Centric Lighting. The idea of everything being connected through the internet, accessible, upgradable, and monitored from anywhere at anytime is the big sell. Refrigerators that not only tell you when a product has expired, but automatically places an order for a replacement is one proposed far-reaching concept. Products that learn from our use cycles to adopt and send data to manufacturers for product development is another. Lighting that responds to local natural light conditions without local sensors. Power grids constantly adjusting in anticipation of user demand. Facilities managers, utilities, and end users accessing and monitoring building activity, condition, and Read the rest of this entry »