Posts Tagged ‘LED’

My first LED fixture - 2004-2006

My first LED fixture – 2004-2006

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.

There are many subjects in lighting, specifically in the universe of solid-state lighting, that need to be actively discussed and openly debated. Issues such as qualitative issues (color, color accuracy, glare, brightness, illuminance levels, etc..) over quantitative (lumens per watt), or the discussion of blue light content, or scotopic v. photopic, or supplier issues, or even the problems of being a small fish in a pond filled with big bloated corporate fish and a governmental agency who believes itself now a lighting expert… These all require active dialog to be resolved and grow understanding.  Too many times, the discussion of important topics are held in little rooms, hidden from view, with conclusions drawn, recommendations and regulations written – to be handed down like tablets from the mount, for us all to simply step in line and accept as fact. We have far too many instances of white paper writing scientists issuing their narrowly focused findings through their myopic peer groups, to be used as swords and weapons against the unwashed and unknowing masses. I find the creeping movement of lighting away from its roots as a human experience enhancing art-form into the hands of marketing zealots, narrow minded PhD’s working in their corporate labs, and federal or state agencies with agendas to follow outside our need to know… well, disheartening and disgusting. (more…)

In my previous entries regarding the Cree LR6, I’ve noted the good and bad sides of the product in some detail. I’ve noted my dissatisfaction with the brightness of the diffuser, which has caused me to first apply plastic trim rings to add a little cutoff, then later, to simply not turn them on. Dimming performance over the years has been disappointing as well. No dimmer I have found has dimmed them satisfactorily, most cause them to flicker. The latest from Lutron, designed specifically for LED/CFL sources, did not fix the issues, so I simply gave up. Rather than remove these expensive retrofits ($65.00+ each), I chose to do what many of us do when caught in a  quandary – stopped using them at all. Estimating these were not used more than an average of 1 hour a day for the last 4 years, total operating time is less than 1,500 hours. I’ll give them 2,000hrs, assuming that when they were first put in place, I used them more than I did as we grew tired of their glare and flickering under dimmer control. (more…)

Like the previous reviews of light meters, I am restricting this review to affordable temperature meters I have direct experience with in actual project work. Anyone who works with or applied LED technology should consider investing in some form of reliable temperature meter to test results of either products in development, or product performance in the field. The Achille’s Heel of solid-state technology is its susceptibility to failure and degradation from operating at high temperatures. This extends beyond the LED into the driver and power supply components, which are often placed under stress from fixture packaging or location near heat sources. The first issue that a manufacturer will raise when facing a field failure, will be the temperature the fixtures were operated in, either caused by the product design, or the physical application, heat kills LED products. That said, just like photometric test equipment, laboratories and large engineering departments will spend many thousands of dollars on test gear, and calibration services. That’s great if that is the focus of your business. For the rest of us, especially those in small business, the costs of test equipment must be weighed against the myriad of other tools and expenses. So, the question becomes, can one keep the costs low and still get reliable results. The following is an attempt to provide some insight into this, and show solutions I have found to be reliable after several years of using various products with varying degrees of satisfaction. (more…)

For anyone interested in saying hello in person, to knock ideas around, or just tell me what you think of things, meeting up at a conference is ideal. Since I try to bring original content to each venue, the time it takes to put a presentation together is enough that I usually limit the number of presentations to 3-5 a year. This year is about over, but I do have 3 more to go on the schedule, for anyone interested. (more…)

In a recent article published in Architectural SSL on the topic of blue light content of LEDs, I attempted to present the discussion of blue light from the perspective of those raising concerns about blue light hazards against known and practical objective knowledge on the topic. The article covered the gambit of concerns, from retinal damage concerns to melatonin levels in occupants, from both sides of the argument, as there are those who dismiss this as a non-issue out of hand. The article also forwarded two conclusive suggestions. First: The research on this specific topic, as it relates specifically to LED light sources, is a little thin. Second: For those concerned about blue light content, selecting LEDs of a lower CCT and higher CRI delivered the lowest blue light content. Whether or not this is the best choice for visual acuity was not the subject of the article, nor was it suggested as the best solution overall. There is a great deal of research supporting the concept of high CCT light for enhancing human visual performance. Much of this was completed under light sources other than LEDs, so there is no caveat included that states anywhere that blue light content of LEDs is at acceptable levels, or of no concern. (more…)

After reviewing a range of different metering choices in actual use, I compiled a summary of findings, as well as my own personal subjective ratings of features and overall utility as a lighting professional. This chart is the collection of all findings in a simple comparison table for those who find this useful (like me): (more…)