New Architectural Lighting Blog Image Gallery!

Just a quick note to let you know that I have posted a gallery page (click the “gallery” tab at the top of the blog just under the header or click here) . Currently it contains a small collection of some of my 3D renders and sketches of concept LED-based architectural lighting fixtures.  I will add to it as I can. Let me know what you think!

Application note: LED Use in Wall Washing Applications

Introduction

LEDs are quickly expanding into the world of architectural lighting into many specific applications once occupied by metal halide or tungsten halogen lamps (think MR16 sized) such as spot lighting, marker lighting (stairs, railings, doorways etc..), and wall washing. Its this last one that I want to talk about here – particularly the pitfall of color temperature as it applies to white LEDs.

Wall Washing? I don’t even clean my windows!

Multi-colored exterior wall washer lights. Courtesy led24.de

Wall washing is when a light or series of lights, usually but not always colored, are positioned and often aimed (physically or through the use of lenses) to spread a wide swath of light onto a wall. Colors can be used for moody effects and colors can be blended from lamp to lamp even within a single fixture. You’ve seen this a lot on the exteriors of large buildings – particularly modern designs or highly stylized buildings such as theaters, casinos, hotels, arenas, etc… Sometimes wall washing – really a sub- type of effects lighting – is used to great effect indoors as well – not only on larger expanses of vertical walls (you typically see larger metal halide or halogen lamps used for very large walls) but equally well on smaller walls, particularly when using LED fixtures.

Why use LEDs for wall washing?

Well for several reasons really. Generally the same reasons for using LEDs in most any application they can fit into – cost savings on both maintenance and energy use, heat reduction, ease of dimming/cycling, and size reduction. I’m not going to go into a full-on discussion of LEDs versus lamps (I’ve already done that) here but I will talk briefly about their advantages in wall washing applications. Thanks to the LED manufacturers (particularly Cree and Osram) and their latest generation of high powered LEDs with their much increased power output – LEDs can be put to the task of replacing the typically hot, energy hogging, high maintenance metal halide and halogen spot lamps. Here are some comparisons in no particular order:

• LEDs are much more efficient in their energy use than halogen or metal halide lamps leading to a cost savings in energy over time.
• They are much smaller even when considering the use of additional focusing lenses for wall washing/spot applications, they do produce heat but far less heat and what is produced is thrown out the back and can be easily directed away from the fixture (the fixtures themselves – often extruded aluminum can be heatsinks in their own right) – so the light itself is not hot whereas a metal halide spot light tightly focused on a wall could melt the paint right off if care isn’t taken. This also means they can easily get wet outdoors since an LED wall washer throws no heat in the light, the lens or window sealling off the LEDs won’t heat up and crack when hit with cool water like it can with lamps throwing lots of heat.
• Due to the really small size of LEDs (even high powered ones), one can create substantially smaller fixtures – even when considering the relatively small MR16 type halogen lamps the LED fixture is generally smaller.
• LEDs last, on the whole, waaaaaayyyy longer than lamps. Halogens typically last under 2,000 hours of continuous use and metal halides typically under 10,000 hours but almost all LEDs have lifetimes of 100,o00 hours of continuous use. While I’m on that subject – the lifetime of a halogen or metal halide lamp is defined as “when it’s dead and won’t turn on anymore” where as lifetime for an LED is defined as 70% or less of it’s initial output” meaning LEDs won’t typically just blink out but will dim and/or color shift when they are considered at the end of their life. So, due to the extreme lifespan of LEDs – you get a huge boost in the maintenance savings since your not out replacing bulbs all the time. Kewl
• Since LEDs are solid-state devices, they can be turned on and off at will with no ill effects whereas turning lamps off and on can over and over again shotens their lifespan. They can also easilly be dimmed but so can lamps – in fact lamps typically only need a small rheostat to dim whereas LEDs need a more complicated pulse width modulation module (PLM module) for dimming. Since the power supplies (called drivers) are solid-state themselves, they are typically small and can allow for all sorts of new, innovative features such as computer control and real-time feedback on LED parameters plus LEDs are all low voltage DC where as lamps, especially high-powered wall washers, tend to be AC although a lot of low-voltage halogen lamps are used but their output is not particularly ideal for large wall washing applications.

What are some of the pitfalls of using LEDs in wall washing applications?

Well, the initial cost of LEDs is generally much higher than traditional halogen or even metal halide fixtures and due to that initial cost, it can take a long time in cost savings from efficiency to pay for the expense. Power output – lets face it, it takes way more LEDs together in an array (at much greater cost) to make the same power output of a modest halogen spot lamp which costs like a tenth of what the LED array would. The more LEDs you use, the more drivers you will need and if your utilizing dimmers or computer control, more LEDs increases the complexity of the wiring. Lastly, color temperature – which isn’t really a problem with lamps, can be a BIG problem with LEDs. Colored LEDs aren’t as much of a problem but color temperature variation really comes into play with white LEDs. Non-colored lamps tend to be very consistent in color temperature between lamps but due to the complexity of manufacturing and how white LEDs are made, you can get considerable variance which must be delt with as I recently learned.

Color Temperature Variations

Well, this is the crux of this application note and the reason I am writing today. Color temperature. Color temperature (given in degrees Kelvin) refers specifically to the visual rendering of a white light as compared to that of an ideal black-body source where the temperature of the black body source causes it’s light output to match that of the compartive light source. The “warmer” the color temperature, the more yellow it appears (but the lower the actual color temperature 2700 – 3300 K – kind of weird huh?) and the “colder” the temperature, the more bluish it looks but the higher the color temperature is (+5000 K). What may look white to you at first glance may not be – it could be bluish, yellowish, or variations in between. Halogen lamps are black body sources and tend to be yellowish and metal halide lamps tend to be quite bluish but they tend to be quite consistent from lamp to lamp due to the physical properties of how they generate light (really, REALLY, hot elements and gasses) . LEDs being solid-state devices and there can be considerable variation in the manufacturing process. “White” LEDs are typically made by taking a blue LED chip and coating it with a yellow phosphor that glows or phosphoresces when hit by the blue light but phosphors of various colors (green, red, blue etc…) can be stacked in various thicknesses on top of various base LED chips (sometimes near UV chips are used) to create “white” LEDs. It’s precisely this amount of variability that can lead to color temperature problems in white LED applications. Generally, you would want to stick to one LED type from one LED manufacturer to eliminate possibly using different types of phosphor coated LEDs but even then the LED manufacturing process can produce considerable variability even among one LED type from the same manufacturer. Generally, LEDs are produced in large batches of 10’s of thousands of LEDs and all the LEDs from a single batch tend to but not always have similar color characteristics. Through the use of automated spectrophotometric equipment, LED manufactures can futher sort or bin their LEDs by their specific color temperatures – putting the more white LEDs together, the yellowish LEDs together, and the bluish LEDs together in smaller batches or bins. Depending on the manufacture and how sophisticated their equipment is and how demanding their customers tend to be – even amongst individual color bins you may still find some variation. The quality of binning tends to vary from manufacturer to manufacturer and it is often directly proportional to how many LEDs you order.

Prominence of color temp variation in LED color rendering varies with distance between fixtures & between LEDs themselves

Generally, you can get more picky about color binning when ordering huge numbers of LEDs and you have no say at all really when order less than a 1,000 pieces – something to consider. Generally, however, the variability from LED to LED within the same lot or reel tends to be ok with a few deviants. Its when you start mixing and matching from various reels/lots that you can really run into problems. In practical use, you may not ever notice that a

“white” LED isn’t quite white depending on it’s use – with spot illumination applications like down lighting and task lighting you may not notice particurlarly where you tend to have one LED or a very tight cluster of LEDS all emitting a narrow cone of light or the spot fixtures themselves aren’t that close to each other but the color shift is particularly pronounced in wall washing applications

where the light fixtures are very linear and you may have several inches between LEDs (preventing their output mixture until several inches to feet up the wall) and the fixtures tend to be put one after another in long strings. Walls tend to be like a blank canvas and where the light tends to be right up against that canvas, you really start to notice the color.

Practical Lesson

I know all of this since I recently worked on an LED wall washing application where the color of binned LEDs shifted all around even though the LEDs all came out of the same bin. The binning wasn’t terrible (it could have been better) but our contract manufacturer didn’t consitently use all of the LEDs from a reel before moving on to the next when populating the module boards. We had hundreds of linear LED modules with 6 high power LEDs on each and each with a prismatic, directional lens on them. Each was supposed to be a nice warm color around 3000 K. However, what we got were many, many LEDs that produced amber even dark amber LEDs that when placed up against a white wall, looked yellow – I mean you’d call these “yellow” LEDs

The effects of color temperature variation of white LEDs in wall washing applications

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Plus we got some that were pinkish in color, greenish, and even orangish in color yet they all came from the same bin. These colors, even many inches above the actual LEDs would mix and create unattractive hues on the wall but were particularly noticable right above the LED. See my ugly illustration to the upper right to get an idea of what happens. Anyway, since the boards were all made up with the LEDs on them through no fault of our own, we quickly had to use our expertise and start pulling these surface mount LEDs off them and doing our own “binning” to get boards with uniform color outputs from each of the six LEDs. Was this a nightmare? Yes, but a lesson learned – check LED color temperatures wherever possible even if the LEDs all come from the same bin when the application demands it, like color sensitive wall washing applications. Make sure that lot/bin numbers are carefully checked when assembling devices from LEDs and stick to one lot or bin when placement of LEDs will allow for color mixing such as a linear array.

Conclusion

Well I hope my thoughts or rants made some sort of sense to someone. Let me know what you think. Have you had your own experiences with lousy color temperature variation in white LEDs – let me know?

P.S. The solution to this is…..

If you want to know what the quick, easy, and dirt cheap solution we came up with for this problem is – click here to find out

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Clearing the attic

Well, it’s been a looooonnnnnnggggg while since I posted anything. It’s been soooo hard with other commitments within the company and outside the company but I am still pushing forward – albeit a bit slow. Thank you for all of the comments lately, it’s really nice to see that many of my readers are participating.  I have been invited by a couple of blogs for link exchanging which is really cool and that is something I am always open too. If your blog relates to architectural lighting in a meaningful way, then I am totally open to that. One thing that I am not really open to which has come up is that I link exchange WITHIN a post. Let me say that I am not offended by anyone asking so don’t worry about that but I am not going to place links/ads within the blog outside of the blogroll but thats not to say I wouldn’t consider it if there was some really deep connection on a technical level that would really enhance the post.

Well that’s it for now. I’ll be posting a small lighting application note soon.

You mean a daylight planner ISN’T a little book I schedule my appointments in?!?!?

Here is a terrific yet brief article about what exactly daylight planning is and what a daylight planner does as it refers to architecture (not how your family spends April vacation . Think of it as a quick primer on the subject. Includes a neat little glossary of commonly encountered terms when dealing with a building’s daylight plan.

Check out the article

Technorati Tags: architectural lighting, architectural lighting design, solid-state architectural lighting, led architectural lighting, architectural led lighting, lighting design, solid-state lighting design, lighting designers, lighting artist, artistic lighting, lighting engineering, architectural lighting industry, designing with light, architectural design, office lighting, daylight planning, daylight planner, daylight consultant, daylight consulting, building daylight, natural building light

How LED lighting can save on costs and help the environment

Harking back to a topic I posted earlier on this blog about LED replacement lamps for amusement park rides or lack thereof I thought you might find a recently published article from Funworld Magazine in which I was quoted interesting. Hopefully you find it interesting, I enjoyed being interviewed by Ms. Gable and I think the article illustrates some of the pros and cons of adopting LEDs within the amusement ride industry. Give it a read.

As usual, your comments are appreciated!

Click here to read the article on the International Association of Amusement Parks and Attractions website

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Story on LED Replacement Lamps Highlights Need for Standardized Testing Methods

I recently read a story on LEDs magazine about Toronto’s Palace Pier condominium tower becoming the largest residential LED conversion in North America. The Palace Pier is an upscale, 44 floor condo building with spectacular views that the designers wanted to carry over into the interior of the building. They replaced the existing 1300 MR16 halogens with direct MR16 replacement LED modules. The halogens consumed 35 watts of electricity versus 4 watts for the LED replacements. Kudos on being green!

The thing that I found most interesting here is that the contracted company providing the replacement LED fixtures does not put up complete specifications for either of their replacement LED products:  no datasheets, nothing specific. Just a general 300+ lumens for their MR126 replacement product. I question the comparison in brightness between MR16 halogens and the LED replacements. The story just says comparable brightness but when you go to the CRS website, all you see is the 300+ lumens. Ignoring the fact that lumens is not brightness but total light output in all directions as measured in an integrating sphere, 300 lumens isn’t even close to the 1000+ lumens light output you get from a typical 35 watt, 12 VDC MR16 halogen lamp. What I am sure they are referring to is center beam candela, which is a brightness measurement but their website doesn’t have that specification. Perhaps the MR16 halogens they are replacing weren’t particularly bright, a very real possibility but who knows? I’m sure the fixtures were tested, at least by their own eyes, to make sure they were as bright or brighter but the published specs alone don’t bare that out. I am also sure that in this case it is just an oversight but it does lead me to ramble on about something that is all too common in the industry these days: confusing. missing, or misleading specifications.

Unfortunately, beam candela measurements have to take into account the measurement distance and the angle at which the beam is sampled, neither of which needs to be defined in the results. So a manufacturer that took a measurement at 4 feet away from the lamp over a 26 degree sampling angle and only came up with 480 Candela could retake the measurement at 3 feet from the lamp for a 10 degree sampling angle and get a more favorable 950 Candela and publish that as their spec without saying it was measured at 4 feet at a sample angle of 10 degrees. If these were separate manufacturers and separate lamps, how could you make a direct comparison based on 480 candela versus 950 candela without knowing the missing information? You couldn’t, really. Beam candela refers to how bright a narrow beam of light will look to an average human observer at some specific distance away. A lamp such as the replacement lamps used at the Palace, may only output 300 lumens but at a very narrow 15 degree beam angle so the brightness at, lets say 4 feet away may be quite high compared to an MR16 halogen at the same 4 feet with a more impressive 1000 lumen output but with a broader beam angle of 30 degrees. Kind of confusing isn’t it?  One lamp manufacturer may publish their 1000+ lumens as a measure oft their lamps brightness while another may publish 850 Candela as theirs. So which one is brighter? You’d have no clue without actually buying each and testing them both. Errr!

As an LED manufacturer and distributer, I have a real problem with LED lamp manufacturers that do not put up their specifications and when they do, they only put up generalities or use the more confusing numbers such as lumens as an indicator of brightness. This leads to confusion and hurts the industry as a whole. I know of several large companies/institutions that would switch over to LED lighting if the market weren’t full of confusing and misleading numbers. They just won’t take the chance. The DOE, working on standardized testing methods for LED based architectural lighting, has run into this big time with submissions that had stated outputs no where near what the DOE’s testing bore out. Click here to read more about the DOE’s efforts on standardized testing methods for solid-state lighting.

Well I’m not going to go on much further. I said what I wanted to say. I’m not impugning the company in the story. In fact, congratulations to them on their success on this project. I’m merely citing the story as an example of an industry-wide practice that needs to improve if solid-state lighting hopes to make it into every home.:(

Click here to read the full story at LEDs Magazine

Technorati Tags: leds, solid-state lighting, lighting industry news, lighting industry market, lighting market, solid-state lighting, led news, led technology, leds in the news, energy star, energy-star, energy savings, saving energy, energystar, energy efficient, residential lighting, residential lighting projects, led city, led cities, led-based residential lighting, led residential light, residential leds, residential light design, residential street light, architectural lighting, architectural lighting design, solid-state architectural lighting, led architectural lighting, architectural led lighting, lighting design, solid-state lighting, department of energy, us department of energy, us doe, doe, commercial product testing, product testing, standards and procedures, ssl product testing, solid-state lighting product testing, led specifications

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LEDs Modernize Time’s Square New Years Eve Ball

Thanks to reader Kc for giving us the link to a great article about the new LED version of the venerable Times Square New Years Eve ball.

This year is the 100th anniversary of the New Years Eve ball and the ball has been completely redone by Waterford Crystal and has been updated with a brand new, sophisticated LED lighting system by Philips Lighting. Philips has replaced the 600 incandescent light bulbs and halogen bulbs with 9,576 Luxeon LEDs to give us all a New Years Eve ball that is brighter and way more energy efficient. Another benefit, provided by Focus Lighting, is that the LEDs are now under better computer control and can produce millions of colors and changing patterns of light never before possible with traditional lighting.

Anyrate, click here to check out the article, it’s well worth it. There is a brief history of the Times Square New Years Eve Ball and also a video of the New Ball.

Technorati Tags: leds, led modules, accent lighting, architectural lighting, engineering lighting, light engineering, color changing light, color cycling light, rgb leds, color leds, light design, designing with light, lighting design, architectural light industry, leds for fun, fun with leds, led projects, projects with leds, solid-state architectural lighting, office lighting, lighting in architecture, architectural design, innovative architectural lighting, Philips Lighting, Philips LED Technology, Waterford Crystal, New Years Eve, Times Square, Times Square New Years Eve Ball, New Years Eve Ball, Time Balls, Focus Lighting

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Colored LED Replacement Lamps for Amusement Parks, Theaters, Whatever

Hey! All you amusement park enthusiasts, operators, owners, whatever…In reference to an article I recently ran on my LED Development Blog about amusement parks not updating to LED lighting when they have thousands of colored incandescent lamps burning out all over the place: I mention that colored LED replacement lamps are just now becoming available but demand is low so availability and cost are high. I didn’t quote figures since, to tell you the truth, I lost the address to the one web page where I could find colored LED replacement bulbs when I wrote the article. Doesn’t matter since I have now found a much larger source for these types of LED replacements: LEDTRONICS, INC. Click here to fly over to their web page with the appropriate S14 LED Replacement bulbs but make sure these are the actual types you need since they do make quite a few other types (these were the type I was referring to in the article). Anywho, these S14 LED replacements were installed in several high-visibility projects including the Bardavon Theater in NY. LEDTRONICS has a great press release/case study showing the theater and throws some savings numbers out. The theater before and after shots are amazing! Quality of LED light compared to incandescents is something that doesn’t get mentioned often but maybe it should. Hmmm….

As expected, the cost of these bulbs (list, single quantities) is very high at around $40.00 each. Compare that to a colored incandescent S14 at $0.98. The energy and maintenance savings offered by these replacements is where users will really benefit. These have a reported life of 100,000 hours. Compare that to a typical, long-life colored S14 incandescent life of 5,000 and you can see where the LED S14’s will really begin to pay off. Better still that 5,000 hours for incandescent S14s is reduced to something on the order of 1,000 hours when they are cycled on and off as they typically are in amusement parks or theater marquees. LED replacements are not effected by cycling.

Anyrate, I thought you might be interested. If anybody uses these LEDTRONIC S14’s or any other colored LED replacement bulbs for high volume installations like amusement parks, theaters, or whatever (particularly high vibration or flashing applications) I’d be interested to hear from you. Even if you’re contemplating LED replacements in high volume but haven’t done so,I’d still like to hear from you. Tell me your thoughts, reservations, experiences, social security numbers (just kidding), etc…

Technorati Tags: leds, solid-state lighting, lighting industry news, lighting industry market, lighting market, solid-state lighting, led news, led technology, leds in the news, global industry analysts report, energy star, energy-star, energy savings, saving energy, energystar, energy efficient, municipal lighting, municipal lighting projects, led city, led cities, led-based municipal lighting, led municipal light, municipal leds, municipal light design, municipal street light, street lights, led street lights, led streetlight, led streetlights, municipal streetlight, municipal streetlights, architectural lighting, architectural lighting design, solid-state architectural lighting, led architectural lighting, architectural led lighting, lighting design, solid-state lighting, amusement park, amusement lighting, leds in amusement parks, ride engineering, ride lighting, ride design, amusement design, amusement ride design, amusement ride lighting, amusement ride leds, leds in amusement rides

Zumtobel Implements Large-Scale LED Lighting Installation

Vienna mall lighting is largest LED order for Zumtobel
Kudos for Zumtobel and Ledon! It’s always great to see LED innovation in architecture but the one thing, I think, that is on everyones mind is how the heck do they keep a 23-meter high waterfall frozen? If anyone of my readers happens by the Stadioncenter, please take a look and let me know.

Technorati Tags: architectural lighting, architectural lighting design, solid-state architectural lighting, led architectural lighting, architectural led lighting, lighting design, solid-state lighting design, lighting designers, lighting artist, artistic lighting, lighting engineering, architectural lighting industry, designing with light, architectural design, office lighting, solid-state office lighting, office lighting design, leds , solid-state lighting , lighting industry news , lighting industry market , lighting market , solid-state lighting market , lighting market analysis , global led market , global led news, global lighting industry , global lighting fixtures , global lighting , led technology , leds in the news, shopping center lighting, lighting shopping centers, lights in shopping centers, led shopping center lighting, zumtobel, ledon, stadioncenter, Vienna architecture

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Department of Energy Finalizes Energy Star Requirements for Solid-State Lighting

DOE issues final Energy Star criteria for SSL products effective 30SEPT2007
In an effort to accelerate the market introduction of highly efficient LED-based general illumination products, the DOE is leading the Energy Star management for SSL lighting, keeping tighter control of standards and implementation to avoid the fiasco that compact fluorescent lamps (CFLs) endured and are only now just recovering from just in time to watch LEDs steal a significant portion of the market with the advent of newer, higher-output, and more efficient LEDs (click here to read about Cree, Inc.’s XLamp achievements).

The final Energy Star requirements can be downloaded from the DOE SSL website
at www.netl.doe.gov/ssl/energy_star.html
(scroll down to the bottom of the page)

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