The Great Blue Light Panic Keeping Some Folks Awake
If you read alarmist comments on the inter-webs about the dreaded “Blue Light Hazard”, you may come away thinking that your TV, tablet, phone, and LED bedside lights are depriving you of sleep. Yes, the spectral power content, including blue light, can produce amplified melatonin suppression that can indeed disrupt your ability to fall asleep. And, yes, LED lights and many LED based displays do produce blue light at the wavelengths of greatest concern. We’ve been all over this, and there have been thousands of other discussions on this everywhere, including in mainstream media – which for the most part get it all wrong. Continue reading “Bedroom Lighting for that Restful Sleep”
The Navy utilizes red task lighting at night to preserve vision of bridge occupants during certain operational conditions. I was asked to provide a version of the Tasca work light to be used on the bridge for map lighting, to replace incandescent products with filters they had available to them through the GSA. They wanted white light for supplemental daytime use, and red for operational conditions where red light was employed. They also wanted dimming for both conditions. To accommodate this, I added (2) Ledengin 625nm Red LEDs to the standard Tasca head, which employs a Bridgelux 4000K ES COB array, with a custom diffuse optic. One driver is all that was required, with a three position toggle switch that selects white-off-red. This allows one dimmer to be used as well for either mode. In addition to these light output modifications, they also needed the arm system to be extended vertically 6″, with a swivel mount to a bolt down base. I added a swivel lock as well as an adjustment for setting swivel resistance while I was at it, for extra measure. This is now used on two ships, with more on the way. Continue reading “YOL 2015 – D13 Navy Bridge Tasca Light”
Overall height is 19″. The base is a salvage item from Goodwill.
I am a task lighting fanatic. I use them everywhere, so am always looking for something new to add to my collection. In this installment, I am addressing the need for a light that is compact, delivers intense light (1,200+ Fc) with no glare or brightness, and high color accuracy. The application is pretty straightforward, from soldering station use where a magnifying glass is used, to fine detail work inside or on the outside of models. For good measure, I also wanted it to aim at the wall as a photo fill light, or straight up as am ambient fill light, and have a dimmer to allow me to set whatever level I want for the application in hand at the moment.
The wiring and components are left skeletal.
With all the practical specifications set out, I decided to let this design be expressive of the gadgetry involved. Let it all hang out. I also decided to incorporate the new Bridgelux Vero LED with its integrated Molex connector, and a Nuventix cooler, just to amp up the tech factor. This is where things got interesting. The Bridgelux array operates at 33.7V (500mA). The Nuventix cooler at 12V. I am powering the whole thing with a 24VDC wall wart power supply. That meant I needed to employ a boost driver for the LED and a buck (24VDC to 12VDC) power converter for the Nuventix cooler. I used Recom components to attain this, and used a cut up experimenters printed circuit board to connect these two to the power supply, the cooler, the LED and the dimmer control. That’s a lot of wires to find a path for, so I decided to leave them to roam free, let everyone see the components as well.
The lever on the left of the head is the on-off slide switch.
This is a style of design I personally enjoy, and have been doing since the 1980’s, where we made little 12V lamps with fiber optics, MR16s, halogen burners, or automotive headlamps, often suspended from structures made of building wire. In this case, the stand I found at a Goodwill. It was a table lamp, whose shade was gone, and socket was cracked. I liked the cast iron base and single post stand, so nabbed it for a dollar and tossed it in the pile with my other finds, waiting this moment to be put to service.
The wiring at the driver and power supply are exposed as well as the mess of wires leading into and out.
If you look at the head, the switch is a sliding action, on the left side of the head. Pull it forward to turn it on, push it back to shut it off. A hole in the side of the housing allows you to see the action inside. No, there is no reason for this, other than it seemed more appropriate than an off-shelf toggle or twist switch.
The light on the task surface is at 1,425 Fc, the LED is 3000K, 97CRI.
The head can pivot 180 degrees from down to straight up.
The Cure Cube is used for curing SLA 3D Prints created on the Form Labs 1+ printer. Exposing SLA prints to 405nm “UV” light increases strength and creates a harder surface for final finishing.
While not particularly visible to everyone in the SSL universe, over the past few years one area of interest in LED product development for me has been in use of 405nm LED light sources to cure various plastics materials. The advantages are lower power requirements and reduced overall heat in the cure zone over conventional fluorescent or HID light sources. This has been of particular interest in curing fiberglass resins manufactured by Sunrez. The typical demand is for between 200 and 1,000 µW/CM² at 400-405nm wavelength. The use of LEDs allows us to generate exactly that without the waste of visible light, and longer wavelength power the resins are not reacting to. In one project, we were able to replace a 1,500W HID light source with a 120W LED light system that produced faster cure times with less than 10% of the total power, and virtually no heat added to the heat generated by the resin’s exothermic reaction to the curing initiator. Since then, we’ve built 405nm light cure fixtures ranging from 1,200W to 25W.
In this case, I needed to cure 3D prints we generate on a Form Labs 1+ 3D SLA printer, and do so in an office environment without exposing other materials and occupants to UVA light output. The material used in the print process is acrylic based, with chemistry that is photo-reactive to 405nm. The actual prints are made using a UV laser source. When the part is removed from the printer it is washed in alcohol (91% IPA), rested for a few hours to dry the alcohol off, then placed in this cure cube for an hour or more, depending on the thickness of the final component. The end result is a hard first surface for finish sanding or painting, if necessary, and a more rigid part as a whole (less flexible).
The cube is simple, with vent reliefs top and bottom to encourage ariflow. The flush switch on the top cover was created using 3D printing processes for the slider and body, as well as top and bottom cover.
The cube utilizes a simple aluminum housing, with FDM 3D printed top and bottom covers. The top cover houses a single Recom 500mA driver, slide switch and wiring terminal block on a Tasca LED driver circuit board.
5mm 450nm LEDs with a FWHM distribution of 60º, 25 per side and top (125 total), operating at 20mA each, mounted to custom circuit boards sourced at Express PCB. Each board connects the LEDs in parallel, while the boards are connected in series, resulting in a 500mA, 15.4V circuit, totaling 7.7W. The boards and internal exposed surfaces inside the box were then covered with White Optics 98 matte material to increase total light energy and diffuse The light energy at 405nm is roughly 600 µW/CM².
The bottom surface includes a glass plate where the product sits in order to make any possible stickiness of a part from adhering to the White Optic material below.
The interior of the cube is covered with White Optics 98 material for optimizing light energy re-cycling.
The housing was powder coated matte black polyester to make clean up easy and the box look nice. The overall interior dimensions of the box are 1″ larger than the total build volume capacity of the printer itself (5 x 5 x 6.5), as any over-sizing is unnecessary. This produces an optimal match between the location of the LED sources and any part the printer can produce.
The Cube is powered by a remote plug mounted 24VDC power converter.
The operation of the box is simple enough. The box is lifted up, the part is set on the base, the box is set over the part, and the light is turned on by sliding the switch to the on position.
Simple and compact is the order of desktop manufacturing, and this fits that model perfectly.
A look into the box lighted up and ready to accept parts.
Testing so far has shown the cube can cure raw resin from liquid to fully hardened in less than an hour, and strengthens prints in that time or less. The heat generated from this arrangement is so small, there is no chance of any part being warped or affected by the process, other than the desired results of becoming stronger.
For parts to be left unfinished, that are desired to be used over extended periods, we coat the finished parts in either acrylic or polyurethane UV inhibiting clear coat, gloss or matte. This stops ambient room light or daylight exposure from making the parts brittle over time. I am building a second copy of this cube for completing extended testing of samples of the materials we are using to verify clear coat effectiveness, behavior of the print material over long exposure periods, and the behavior of these low cost LEDs over time. A commercial version of this cube could be made using more robust LEDs, but the costs would be significantly higher as well. In the current configuration, the LEDs only cost $0.60 each, so should they last a couple of years in use, replacement of the populated boards is a simple task, while the cost of higher power LEDs would have increased the cost of the entire end-product by as much as three times.
There is also an additional version of this same approach in using Red/Blue light sources for use in plant seedling starts. We’ve found tests with common rye and barley grasses, the time from germination to hearty growth ready for planting is accelerated significantly. Using an enclosure like this allows the plants to be exposed to intense light for extended periods of time (18 hours or more) without polluting the surrounding environment with the ugly light, just as the enclosed cube protects room occupants from exposure the the UVA light. In either case, the cube can be used in any room environment comfortably and safely.
So this gets us off the ground and is D1 of 52 in the series. As I’ve noted at the start, this is an exercise in making progress, and putting SSL to work. This is not a particularly exciting product in and of itself, but it is one that will be used regularly, which more than makes up for its lack of marketing sizzle for the masses – at least in my book.
This is my last bit of housecleaning from blogs being shut down, for the archives. KLW
This fixture is my very first LED light. It started life to be a halogen fixture in 2004, that sat on a workbench waiting completion. The first head got so hot from the 50W 12V light source, it was dangerous, so it sat as I decided what to do with it.
In 2005, as LEDs became viable for lighting, I pondered using them to replace the halogen source, but they delivered so little light, the end product was useless as a desk lamp, so it sat some more. One idea was to insert a Lamina BL3000 LED into the head, but the driver was huge, the light output too little, and the heat still an issue.
Then, in early 2006, while at Visa Lighting, Don Brandt (an engineer working with me at Visa, formerly from Emteq, now working at Cree I believe) were talking through ways of applying the latest mid-power LEDs using a simple PCB. We decided to give it a shot and built a board populated by a vendor with 8 Nichia LEDs. The inspiration struck to power these LEDs with two Xitanium drivers, which at the time were un-potted prototypes, so cutting them out of their housing to be installed in clear tubes to show their interiors off was easy enough. Two push-button switches activated the drivers for a high-low effect, and a heat sink was made up of a machined aluminum block installed in the head where the original halogen lamp and reflector once lived. More details and images of this can be found on the Lumenique archives for the Ratchet fixture.
The fixture itself is made of welded steel structure with a brass head and fiberglass tension springs. The head can be raised an lowered with a ratcheting action, staying level at any height. In the end, I left this fixture with the owner of the Oldenburg Group (owner of Visa Lighting) as a parting gift as I moved on to focus on Lumenique and SSL exclusively.
I thought a lot about what to focus on in 2012 for this series, and decided that I had plenty to share from regular activities of Lumenique, LLC and Tasca. So, the plan is to select something completed in each of the 12 months of 2012 and feature them here. This will generally be products or projects completed for customers, but may also include a report on research work in process, when it adds value.
January Feature – TASCA Renovar Floor Lamp
This is a refitting of a Dazor table lamp, applying the TASCA lighting head, and adding an extension stand to convert a desk lamp to a floor lamp. The product was commissioned by a customer who provided the table lamp, purchased used. From the GSA and other government markings present on the original, it was obviously from a government facility. The table lamp made by Dazor has been around since the late 1930’s, where the fluorescent lamp version graced the GE display at the Worlds Fair.
For more details on this project, check out the summary and full technical specs at Lumenique 12 in 12 for 2012 – January.
For additional details on how you might procure a similar product from one of your own favorites, visit TASCA.
Also, as an update, the Lumenique Product Center now accepts all major credit cards, making your purchase experience easy and secure.
Stay tuned for additional news and updates on the 12 n 12 for 2012 review, and other interesting SSL information.
ArchLED’11 will be marked as the official coming out for Tasca, my work lighting product offering. We presented examples of the base Uno line, as well as several Renovar and one Accent light. If you are wondering what these are, and are curious to learn more, you can visit the Tasca web site now. The sitre is fully populated with pictures and a specification download at:
We have also put several products up on the Lumenique Product Center for direct purcahse. These are semi-pre-configured products with popular options. You can choose one or dozens, we don’t mind.
While I do not intend to make this blog a commercial site promoting products and pitching our offerings, I do need to make a living, so there will be occasional updates to share where we are and what we are doing in this regard. This is how we pay for the fun side of being in the business, and afford the time to invest and share with others information on solid-state lighting.
A Little More on Tasca
Tasca is primarily focused on the work environment. Whether this is a machine operation, an assembly work station, an inspection station, or administration workplace, my intent is to offer the most effective light for enhancing visual performance with a durable product. I’ve invested decades experimenting with task lighting. My personal approach has been to lower ambient surrounding light levels to the minimum required to support the low acuity activities in the space, supplemented by localized task lighting to enhance visual performance in critical work areas. I have applied this in lighting designs over the last 30 years to reduce energy consumption, and live under it on a daily basis. In other words, I am passionate about this approach and believe it is a superior approach to achieve high visual performance. I strongly believe we are over-lighting our work spaces to some compromised light level, which is too high for ambient requirements and too low for effective task performance.
Over the last few years, the idea of creating a work light for hard service environments, bringing the advantages of SSL technology to work spaces that require high visual performance to support safe, accurate, and efficient work tasks. For over a year now I have been investing considerable time building a product I feel satisfies the demands of work environments, with an efficient product that will survive harsh environments. Tasca is the product of this effort, and just the beginning of a larger effort to produce desirable performance SSL lighting products for niche work space demands. We’ve already provided customized versions of Tasca for UV curing applications, and will be releasing specialty products, such as a 98CRI sourced heads for color critical inspection (like printing presses, millwork, textile and paint inspection), as well as a unique welding light that will bring welders vision of their welding field that has never been possible before.
Tasca is also founded on the concept of sustainability from durable products that are recycled either by dismantling, rebuilding, or re-purposing at the end of service life, not just thrown away. Unlike products that are filled with potting materials and irreversible assembly techniques that make recycling too expensive to be practical, Tasca fixtures are heavy duty assemblies designed to be reworked, rebuilt, or dismantled easily for recycling of materials content, separate of the electronics components that must go through a separate recycling channel. This includes the use of glass for the lens cover, which can survive decades of use, or be recycled easily through existing waste management channels economically. The Renovar and Accent line take all of this one step further by harvesting old task lights for their arms, refinishing the devices, recycling the old lighting heads, and converting them to Tasca lights by adapting our lighting heads, before a complete refinish and refurbishing.We will also refit your existing task lights, bringing old favorites back to life by bringing them up to date, or through Accent, create a custom design to suit your specific taste.
This is just the start of a great deal more to come. Sort of pulling the plug out of a dyke and letting things flow. This is an exciting niche opportunity for me, where I can add value through design integration assistance, and provide customization to suit unique customer needs. Unlike imports which must be marketed in large batches of off-shelf products to move production inventories – Tasca is made here in the USA, to order, to meet individual customer needs – even if that means building something completely new and unique that has a total customer market of one.
A little gadget for looking at small things in the shop
Okay, so I couldn’t resist. When I posted designs 49 and 50 last week, I received a note from Kevin Dowling (of CK fame), who also has an old South Bend lathe. He made a comment about a technique called “cloudy day” lighting, where shadows and highlights are removed in a viewing chamber for seeing detail on specular materials. The concept was that this might work as an aide for reading drill bits, which often have very small letters, laser etched on the cylindrical surface. I was intrigued, so created this small gadget.
This is a small chamber with concealed LEDs (Cree XRE’s) at the sides behind shields. The interior is lined with White Optics material to produce indirect light around the subject. It is powered by a 9V battery, with a simple momentary pushbutton switch. It will accept objects up to 3/4″ in diameter. To enhance vision I have added a 1.5X lens at the view window. The combination of bright indirect light and optical enlargement makes reading small drill bits, mill tools, and markings on the side of thin wires significantly easier. I have also found it works very well in viewing the condition of lathe cutting tools, which often look and feel sharp, but aren’t. Looking at them in this viewer reveals flaws impossible to see otherwise. This can also be used to thread needles, read a thermometer of a sick kid, and other surfaces that will fit through the port.
While this is not a perfect cloudy day viewing system, as it does not completely eliminate the dark stripe one sees on cylindrical surfaces due to the opening window, the fault is minor, and does not detract from the significant improvement it offers overall. It also costs a LOT less.
Well, here we are at the end of the year, the last days of the last week. Design 52 is the official conclusion of the 2010 challenge, and is another task and work light. This design is a work in process I have been toying with all year in use of color and white LEDs to produce color and white light, using simple controls. The first effort has been in finding the right mix of LEDs to produce the best result. This represents one version I have found works very well – specifically the GE Vio 830 white LED with two Lamina RGB Atlas light engines. This produces a wide range of white values with CRI greater than 80, and as high as 92.
The light head includes an optical mixing chamber lined with White Optics material and a fine prismatic diffuser lens. Thermal management is through the use of a Nuventix Synjet PAR20 cooler/heatsink, allowing the LEDs to be run up to the total of 24 watts without an issue of over heating.
The challenge so far has been LED selection, the next is driver design. This design is a step forward in that it is designed to use the Verde Designs 4 channel programmable current driver package. This driver can be controlled with 0-5V, 0-10V, and DMX, which will facilitate incorporation of a controls system that will add greater fidelity to color selection, as well as eventually including a feedback loop to make corrections as things heat and cool during operation.
So who cares about color in task lighting?
Well, the inspiration came when working on a wiring harness for a motorcycle project. There were more than 40 color combinations in the harness, including stripes and solids. Some of these combinations were giving me fits. For example, the faded old black wires, brown wires, and dark purple wires all looked the same to me. As an experiment, I threw together a simple RGB light and pointed it at the harness. With a little fussing around, I found a color combination that made the wire colors jump, no more mixed wires.
Since then, I have found instances where adjusting the CCT of white, or amplifying one color or another came in very handy for either matching colors, seeing color, or simply improving task visibility. This has led to the product you see here.
I also have a theory that for men with color blindness, the ability to either amp up or tune out green and/or red balance in light will be useful in aiding differentiation of reds and greens in tasks where this is important – like electronic wiring, or other color tasks where red and green differentiation is difficult, but important to performance.
So, this is the conclusion of 52 in 52. It’s been quite a year. The project did what I had hoped in getting me deeper into the technology, while enforcing constant state of design exploration. While I do not plan to attempt to repeat this in 2011, there will be new designs presented here, so please drop in and take a look now and again.
Thanks to everyone who has been following along and offering support and encouragement.
For the most part, LED work lights on the market today are useless, low grade junk. While there are one or two (literally) fair performing products, none actually replace halogen or CFL lights at all. In fact, the good old incandescent/metal cage shop light can kick the latest tecnologies tails any time. The drawbacks of a scalding hot lamp and metal shroud, lamps that pop at the slightest banging about, and the lack of any directional control are big liabilities for that old incandescent. The fluorescent lamps are not that durable either, with any rough handling resulting in a popped lamp, while start up in cold temps is sloooooooow, or not at all. Color is also pretty sad, making identification of color coded wires under a dash a bit challenging. Optically, the fluorescent stuff just blows light everywhere, often right in your eyes when your working too near one of them, with no way to control it. The LED crap on the market is poor in light output and harsh with their multiple light sources, also of really poor color. They are essentially bad copies of cheap CFL twin tube junk. The only thing to say good about them is they are pretty cheap, and won’t burn your face when lying next to one under a car or in a foot-well.
Design 51 is a work in process effort intending to create a real LED based shop light that can kick the incandescent and fluorescent products out of the tool box, and put the LED stuff from the catalogs to shame. I started with the LED, in this example using a 1200lm Bridgelux LED. I applied a Lidel 50 degree optic to this. In all, at full operating temp, the light head produces over 911 lumens, with a CBCP of 1300. That’s enough power to put 134 footcandles at the center of a worksurface 36″ away, over an area of 72″ in diameter. It also delivers over 1400Fc at 12″, so there is a hi-lo setting to the power switch, to trim light on close up tasks.
Next, since the LED operates at roughly 20 Watts, thermal management was an issue without making the head the size too large to be useful. Not only that, but shop lights tend to be used in a wide range of positions, and in various ambient temeratures. To address all of this, I used a Nuventix Synjet active cooling system. This little gadget generates moving air over a small heat sink to significantly reduce package size and thermal controllability. In this case, after operating for over 4 hours steady in the high mode, the LED never saw more than 70C, and the outer surface of the light head remains cool to the touch.
With a head in hand, I incorporated the LED driver and the Synjet power supply in the main body. Ideally this will be a single electronic assembly, but for this version, its a combination of parts. I also used a remote 24VDC power supply so the cord presents not potential shock hazard, and can be made from very flexible, fire retardant materials. The mounting attachments snap onto the main body, and provide a hook, a magnet base, a floor stand/stabilizer, and a 5/8″ tripod mount for mounting to any lightweight tripod stand. The head itself tilts a fill 270 degrees, so aiming can be made as precise as one might need. I’m going to fool with mounting gadgets as I put this to use in my own shop.
While this is by no means perfect, or economical, it is infinitely more powerful and useful as a professional tool. Something I cannot say for the rest of the LED stuff I have tested and have on hand. I need light more than I need to save a few dollars. I think D51 delivers not only usable light, but new value not available in other work lights of any source.
Tasca is also founded on the concept of sustainability from durable products that are recycled either by dismantling, rebuilding, or re-purposing at the end of service life, not just thrown away. Unlike products that are filled with potting materials and irreversible assembly techniques that make recycling too expensive to be practical, Tasca fixtures are heavy duty assemblies designed to be reworked, rebuilt, or dismantled easily for recycling of materials content, separate of the electronics components that must go through a separate recycling channel. This includes the use of glass for the lens cover, which can survive decades of use, or be recycled easily through existing waste management channels economically. The Renovar and Accent line take all of this one step further by harvesting old task lights for their arms, refinishing the devices, recycling the old lighting heads, and converting them to Tasca lights by adapting our lighting heads, before a complete refinish and refurbishing.We will also refit your existing task lights, bringing old favorites back to life by bringing them up to date, or through Accent, create a custom design to suit your specific taste.
