Posts Tagged ‘SSL’

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…)

This is the Lighting Passport Flagship set. Includes case and accessories in a neat package.

This is the Lighting Passport Flagship set. Includes case and accessories in a neat package.

I first saw this device at Light+Build Frankfurt last fall. I was impressed enough to find one added to my collection of tools. The Asensetek Lighting Passport is a unique product in several ways. First, it is essentially a meter head (where the cost is), coupled to an iOS or Android device that does all the computational and display work. The lighting head has a nifty slide action receptor cover, so there is nothing to come off or get lost in a bag or pocket. The measurement range is as broad as any of the other spectrometers tested here, plus some. Not only does it produce the expected spectral power distribution, CRI, CCT, CIE 1931 and 1976 coordinates and illumunance in lux and Fc, it also delivers CQS values. (more…)

We have now entered the modern era, where meters are available with a dazzling array of features, at a fraction of the cost once commanded. In this case, the UPRtek MK350S, available also in a lesser featured, and lower cost MK350N version, produces amazingly beautiful results with little pain in the wallet or the head from learning to use it. You may find this also sold under other brand names, such as AIBC, or sold through outlets such as Allied and Ikan. I first saw the MK350S at Light+Build in Frankfurt. A customer of mine also saw them, and was so impressed, he purchased one and has allowed me some time to play with it and in preparation of building up a test lab for his company. (more…)

To compliment a standard light meter, which does a fine job collecting illuminance information, I sought a low cost solution to evaluation of color data, specifically CCT, spectral power distribution and CRI. My goal was to find a product under $2,000, that could be calibrated, that would deliver me color information simply and without a large amount of special technical effort. I found that in the Mightex CCD Spectrometer. At a base price under $1,700, it fit the budget nicely. Of course I added a few accessories to it, and paid them to calibrate the meter with a fiber optic mounted cosine sensor, which increased the total invoice to a touch beyond the $2,000 target… However, in the end, I found the results to be exactly what I was looking for – almost. (more…)

This is going to be a quick one. First of all, no matter what other meters one might own, the basic illuminance meter, with its readout in Lux or Fc remains an essential. You pull it out, press a button, get a number. The issue is with the latest generation of LED fixtures and retrofit lamps. They present a somewhat skewed spectral balance that can cause issues with older meters. For example, my trusty old (very very old) Minolta Color Meter II shows all LED sources as being roughly 200 CCT cooler than they actually are, sometimes, sometimes not. My other old trusty bag filler is a Minolta T-1H, which is great under daylight and tungsten sources, but not so good under LEDs, where  readings are off about 12% most of the time, and when exposed to LEDs with any flicker in them – the meter has a hard time finding a reading to settle on. I also have a Testo 540 digital ligth meter, which is an excellent in-the-pocket device, as it is very slim and includes a cover for the light sensor. At a cost of under $140, they are hard to beat for a simple tag-along meter for general illuminance measurement. (more…)

Introduction

Light meters are an essential tool for anyone involved in the lighting profession. The human eye lies to us with its unique capacity to invisibly correct for brightness variations, while the brain fills in missing pieces and compensates for color variations. For professionals, it is important to see through this biological variability to understand what we are actually looking at. One might ask why, if observers are compensating so readily, is it necessary to have objective understanding? These are the five reasons I feel having sufficient light metering is a critical tool for lighting professionals: (more…)

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

(more…)

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…)