Posts Tagged ‘LED Art’

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.

The recent article: LED Bulb Efficiency Surges, But Light Quality Lags states very well the findings of the DOE and others reviewing LED retrofit lamp performance. While well stated, there are severl missing dynamic issues in the conversation that need to be included if LED is to overcome the failure of the CFL to capture the consumer market it so desperately seeks to dominate.

While efficient, there has been no great interest in the consumer market to lamps with poorer quality at higher prices.

While efficient, there has been no great interest in the consumer market to lamps with poorer quality at higher prices.

The CFL lamp has failed in the consumer market for these reasons:

  1. Light quality is poor in comparison to the far cheaper incandescent lamp. This includes color quality, distribution (photometric) pattern is poor (flood type products)
  2. Appearance and fit of the product into existing fixtures – i.e. ugly to look at, stick out of fixtures, create dark spots in shades and fixture diffusers, etc.
  3. They did not last as long as advertised. When switched frequently, the life of a CFL screw base product can be shorter than a long life incandescent. In outdoor cold climate environments, some fail within a few months. In down-lights and enclosed fixtures most fail even more quickly.
  4. They cost too much compared to incandescent of higher quality
  5. They save some energy, but have so many other liabilities the consumer does not take this seriously.
  6. Flickering starts, flicker under dimming, and 120Hz strobe effects from cheap ballast designs
  7. Slow to warm to full brightness – often taking longer to get up to full light than many products are on for in many rooms (pantry, closet, hallway, etc.)
  8. Mercury disposal concerns for some

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08285I have a fondness for the halogen lamp. From the little 20W bi-pin 12V burners to the 500W double ended monsters, the combination of light quality, simplicity, toughness, light density and versatility filled a special place in the hearts of lighting designers for decades. While there were also  larger iterations of the technology reaching 20,000W, even the most halogen crazed found them to be a bit over the top, setting them aside for special applications. In my own experience, the 20W through 75W 12V burners, 15W through 65W MR16, 35 through 50W PAR36 and 75W through 250W mini-can line voltage lamps hit the spot for a wide range of focused and unfocused lighting product designs. For my personal portable lamp works, the low voltage burners, MR16 and the PAR36 lamps were my favorites. I could create live-structures (where the fixture acted as conductor) using remote 12V power supplies, allowing sculptures to be simple to the extreme.

This simple bridge design was created using building and armature wire, a PAR36 halogen lamp, and a ball bearing counter weight.

This simple bridge design was created using building and armature wire, a PAR36 halogen lamp, and a ball bearing counter weight.

When LEDs arrived on the scene in the late 1990’s, I caught a glimmer of what was to come. By the year 2002, it was obvious that solid-state would be delivering something new, and that the properties of the source technology shared a great deal with the halogen lamp from a lighting perspective, with a huge advantage – far less heat, much tougher and resistant to impact, and very long lived. The only issue was, color quality was initially poor, consistency from LED to LED was awful, and light output per individual LED device was pathetic. This required designs utilize a number of LEDs mounted to circuit boards, wired to drivers that were clumsy at best. The complexity of LEDs in the earlier stages were compounded by the lack of available components, which meant one-off application of the technology was out of reach for anyone not up for custom electronics design. (more…)

The Replacement Dichotomies

Side One: It is acceptable, if not desirable, for LED luminaires to be replaced at the end of their service life. This is a common position among a wide range of LED product manufacturers. They make the case that extracting performance and costs from LED products requires a level of integration that cannot be accomplished using modules. This further forwards to concept that modules restrict design freedom, that integrated products are free to create light source forms to suit the intended end-product design, without restriction of standardized sockets or modules. Therefore, it is proposed, that the highest performing SSL products will be integrated units, replaced at the end of their life with the next generation of even higher performing product. The model often used to illustrate this approach is that of televisions, where the entire units are replaced, rather than serviced, with newer generation products.

Side Two: The single most active market in solid state deployment is that of the direct lamp and fixture replacement space. This includes screw based lamps made to imitate the light output and distribution of obsolete technologies, and extends now to bi-pin linear forms to replace fluorescent sources. Oddly enough, the one lamp form that is not addressed, is the one most universally despised in commercial and residential markets alike – the plug-in CFL lamp – but let us not be distracted by this obvious and blatant oversight.  This replacement lamp direction appears to make the statement that the existing infrastructure of sockets is not replaceable, that demanding building owners and end use customers to replace existing fixtures is a burden beyond acceptable limits. This also forwards the concept that the existing socket forms within compromised products, is acceptable, regardless of its severe negative impact on SSL product performance, design freedom and appearance. (more…)

The coming of spring demands a great deal of concentration when you live in an area that is frozen half the year. For April and May this has meant new projects progressing, outside interests fighting for attention, and the progression of older projects resulting in resolution of old issues. Unfortunately, due to the fact that there are those who feel it is their right to knock off ideas they find from others without attribution or recognition, I am struggling with how to proceed with this effort going forward. I enjoy exploring new ideas and sharing discoveries. I despise finding the results integrated into others offerings without so much as a nod to its source.

That said, for this installment of the 12 in 12 project, I focused on making progress in development of portable light originally introduced in the 52 in 52 project in 2010, and a spring project that is personal and fun.

The Battery Project

In week 4 of the 52 in 52 project, I presented this combination table torch/flashlight. At the time, I relied on lead acid emergency light batteries in an effort to create a reliable light for emergency use, using readily available components. Unfortunately, since then, I have found the approach flawed. The batteries were not reliable when connected in series to generate 12VDC, the charging components were not able to keep the batteries conditioned, and the discharge characteristic of the batteries produced an unacceptably short on-time when removed from the stand. Further, the batteries were far too heavy to be practical, and were expensive. (more…)

To operate, the wheel is spun with the thumb and forefinger at the center knob – with the color wheel exposed to the lighting condition being tested. Can be used to look at light falling on a task surface, or isolated to a single light source.

What you see here is an invention of my own creation designed to provide the operator an idea of whether the lighting system he/she is operating under is producing flicker within the perception of the human visual system. While there is always the wagging finger test, this does not fully expose the subtleties of flicker from room lighting. Here’s how it works:

No Flicker Condition: When you spin the wheel under daylight or a non-flickering lighting system or source, the Red-Green-Blue bars will blend together to create a dull grey appearance to the spinning wheel. As the wheel is spun faster, this will become smoother, with no color apparent at all. If you see any color at all, you are experiencing flicker of some level. Only with a total lack of flicker will the wheel appear to be uniformly gray in color. The best place to see this is under direct sunlight, as this will present no flicker at all.

Noticeable Flicker:  When you spin the wheel under a flickering light source, there is a whole kaleidoscopic of effects that appear. The most notable is the appearance of a rainbow color wheel effect, as the R-G-B regions are blended in strobe effect, that will be very wide at high speed (including the appearance of secondary colors Yellow, Magenta, and Cyan that are not on the wheel at all), to very narrow at low speeds. You will also notice that the radial patterns change in direction from clockwise to counter clockwise as the wheel speed changes. Further, at intermittent speeds, the color regions will turn gray with black wagon spokes, then change back to color at higher. In other words, you will be exploring the world of flicker effects in strobing both light and color, as the wheel is changes in speed. This effect will change both with time and wheel speed. At low frequencies (60Hz for example), the color bars will be very wide, as will the wagon spokes. As the frequency goes up, the width of the bars will be narrower for the same wheel speed.

Intermediate Phases: Sources with very deep modulation depth (on-off contrast) create the greatest strobe effect, and will generate the strongest color bands and effects. Some will produce vibrant changes that move around and shift in color dramatically, creating intense rainbows. However, even if a source does flicker, the difference between its highs and lows may not be as pronounced, or the frequency of the flicker may be higher. This reduced modulation depth or increased frequency will create more subtle color effects, narrower bands, and blurrier wagon wheel movements from the dark bands. This can range from very subtle, to more intense. Some will generate a gray tone similar to a non-flickering source, but with a very very subtle rainbow effect just visible in the pattern area, to very slim edges visible at the margins of the dark wagon spokes. In other words, the less distinct the patterns are, and the less intense the colors are, the lower the visible flicker is. This is often the case in spaces with mixed sources, like daylight and flickering fluorescent sources. If you detect this, you can walk around the space and test individual sources until you find the one producing the flicker, and those that are not contributing. (more…)

When LEDs first emerged, I was one of the many who expressed the opinion that a lighting system that could dim to a warmer CCT, imitating incandescent lamps, would be desirable. I want to take this opportunity to retract that original opinion and thought. I’ve played with it, seen the products available that do it, and have experimented with the approach… and can say unequivocally that I really don’t like it at all.

One of the problems with incandescent dimming has always been the patchwork of CCTs one gets through a space from different dimmer settings for the various products in a room. This has never been a good thing. Further, the change in CCT of an old school incandescent lamp is significantly different than halogen lamps, as it the character of the color. I for one have fallen out of love with the old incandescent lamp long ago. Over the last 20 some-odd years, I have come to use halogen sources over all incandescent forms, preferring the cleaner white color over that yellowy dinginess of the incandescent lamp. Incandescent lamps (non-halogen) produce a decidedly ugly color that I personally feel is misrepresented by their high CRI rating. The fact that the CRI formula will show a dimmed incandescent lamp with the same high CRI number, even when it very noticeably distorts color in a space, is a condemnation of our poor color performance metrics, not an indication of this lamps superior color performance. (more…)