Buzzword: Solid-State Lighting

What it means. Solid-state lighting, or SSL, could be the next big thing in residential lighting. SSL refers to a type of bulb—or lamp, in industry parlance—that uses the movement of electrons through a semiconductor material to generate light. The semiconductor is in a solid block form, hence “solid state.”

Because there’s no filament that heats up (and eventually burns out), SSL is up to 50 times more efficient than incandescent bulbs, claim manufacturers. SSL is also said to last as much as 10 times longer than compact fluorescent lighting and contains none of the potentially harmful mercury that has brought CFLs image down to earth and made recycling them a hassle.

Why the buzz? SSL has existed for decades under the name LED, short for light-emitting diode (the semiconductor material involved is a diode). But LEDs are not the only kinds of SSL. For example, laser technology is a form of SSL, and organic light-emitting diodes, or OLEDs, are on the horizon. As a result, the lighting industry is transitioning toward the more all-inclusive solid-state lighting moniker. “Within the broad category of TVs, you have several options, including LCD, plasma, and OLED. Similarly, solid-state lighting refers to anything that is not a conventional gas-based lighting technology,” says Govi Rao, chief executive officer of Lighting Science Group (LSG), a manufacturer of lighting equipment.

The switch to SSL might also have to do with the marketing of LEDs, which are still leading the way in this technology. For years, LEDs were limited to commercial use, for example in traffic signals and airport signage. The fact that they couldn’t generate pure white light kept them out of the residential market, except as the red indicator lights on electronic devices. But manufacturers are getting closer to a perfect white LED; LSG, for one, just launched a line of replacement LEDs (shown). Unfortunately, no matter how good the technology gets, some consumers will always associate LEDs with Lite-Brite. By giving the lights a different name, manufacturers can in a way reintroduce them to consumers.

Whatever its name, SSL is still years away from wide residential use. But it’s making steady inroads, including for undercabinet lighting. We’re currently testing these task-lighting fixtures for our August 2008 special kitchen section. Five years ago, we wouldn’t have covered SSL, but this year, it’s a theme in the story. Without giving too much away, we’ll just say that the purported efficiency of SSL is pretty solid.—Daniel DiClerico

Comments

[AreaRugs]

I just learned about the problems with compact fluorescents here at work. I work at a rug store and we had a customer call in asking about cleaning up a broken fluorescent bulb from her rug. From what I could find the rug really should probably just me thrown away. I have these things all around my house and I have two little boys. We have started taking them out from anywhere they could possibly be broken. With two little boys that is pretty much everywhere. I am surprised the media isn’t talking more about the potential danger these bulb pose.

[Jo]

How can someone invest in this technology?

[dora gonzales]

I just found out about the problem with compact flouresent today. Unfortunetly I dropped one several weeks ago. I feel the manfacture should put a red label in front of the package so the consumer can learn of the problem immiately upon purchasing the product, I know there is alot of people out there not aware of the problem like me, untill today I received an e-mail from a friend letting me know.

[Eri]

Does this mean that LED's are still the better ones when it comes to energy conservation? It's predicted that prices will drop down in the near future.

[Mark]

I just bought several from an online "green" retailer and am having them returned. The light color they definitely got right: it is directly comparable to incandescent and called "warm white" and with that I am satisfied.

The problem is that they are much dimmer than the incandescent bulbs they are compared to. For example, they compared their 5 watt bulb to a 75 watt bulb, and the 3 watt bulb to a 40 watt bulb. Their light output is much less.

This is unfortunate because I want to be more energy efficient. When advertising, the retailer should simply make a more accurate comparison so I can buy the right light to replace the ones I have. By being far dimmer than advertised, they create a poor reputation for the entire industry.

I took them at their word and did not attempt to compare lumens, which is the directly comparable measure of brightness. A 75 watt bulb emits about 1190 to 1220 lumens according to DOE, while the 5-watt LED emits only 400 lumens.

Live and learn. At least the company is willing to refund me.

[Dave]

Got a dozen CFLs at the Orange County Fair a few months ago. No warnings on the little blister pack. I never gave it a thought. What the government pushes upon us should be safe, right? Any way, when I got home and started to change out my regular lamps I found five of the new and improved CFL tubes separated from the base as I screwed them into the socket. I just removed the base and tossed it in the trash with the tubes as I cursed GE. What good are free lights if they don't even make it into the socket? Seems I should have been a whole lot more worried (and angry) over what they failed to tell us. They can send me to environmental jail, I WILL NOT HAVE THOSE THINGS IN MY HOUSE!!

[Eric Flores]

Notice all the heat sink fins around the SSL in this's article picture? It is because SSL need to stay cool. They do not resist heat. On the other hand, CFL have problem with low temperatures.

So, you must be aware that each technology have its weak point and they complement each other. SSLs are more appropriate for your refrigerator's inside light and CFL whenever you have source of heat neat (like the undercabinet near the range).

You also have to consider the directional nature of SSL. LASERs are the most extreme of them, but LED are also extremely directional. This makes them very efficient as a spot light, but extremely inefficient for broad illumination.

[Kit]

Each light source definitely has advantages and disadvantages. LEDs often advertise light output in micro-candellas (mcd) which is not an apples to apples comparison to lumens. Once recent ebay auction I've seen advertises a high-output LED bulb with a wide dispersion angle (72,000 mcd with a viewing angle of 150 degrees). If you convert the mcd to lumens, this is an output of 340 lumens - less than half the output of a 60 watt incandescent.

Although I haven't seen it referenced elsewhere, I've also noticed a strobe or flicker effect; the lights usually operate at 50-60hz and produce a flicker that I can see in my peripheral vision. For me - this causes headaches after a few hours of exposure - especially if I'm reading.

I can't wait for solid state lighting to overcome these issues. It's only a matter of time. LED lighting is already saving lives and homes as they replace traditional Christmas lights. But until they increase output their application will probably be limited to lowlight/low power environments such as nightlights, landscape accents, automobiles, boats,campers, etc.

I'm surprised there aren't more startups pushing this technology forward.

[Nick Vallerga]

I am trying to do my part to save energy by using the new LED lamps, unfortunately the quality of the lamps is in question. I have had 4 out of 7 lamps fail in the last 6 months! One failed completely and half of the LED's went out on the others. I have the flood type lamps from "Lights of America" I would like to see a Consumer Report test on these bulbs.

[Bob Heine]

I installed eight undercabinet LED puck lights manufactured by Lights of America. When the first one stopped working I tried to find a replacement unit. When I searched for 7200LED-BN a number of complaints showed up in the results. A number of people had failing units but none of the results gave me a source for the replacement bulb units. Two days later a second unit stopped working and in the subsequent six weeks, six of the eight pucks stopped working. I guess undercabinet LED lighting is not yet a viable option. I'll be replacing these pucks with the old reliable halogen units.

[Anonymous]

As a rule of thumb only use CFL's in permanent fixtures with covers (like over the sink in the Kitchen). Don't use them in lamps that can be tipped over (like table lamps). Then, use them preferentially to other lights in the house. I am not as worried over the mercury as everyone else. My dad used to play with mercury when he was a child, out of old thermometers! Have a Mercury spill kit on hand and don't sweat the small stuff people. Also, I have found that BRAND MATTERS. The cheap CFL's are nowhere near as good as GE's.

[david]

any flourecent light has the potential danger as far as ssl that is just the name some one put on it the are and allways will be LED lights they have been around for 40 years more recently white high intensity, so if some one builds a plug and play and uses the standard led's they will be dim, the life would be very short if they ran the rated current to get the rated output and with no heat sink boom. the math does not work out right either
power divided by voltage equal current 2.5 watts 120 volts comes up with 21 mA not the rated 35 mA specified i bought a set of three one quit within a week so being a techie i took it apart lol it's a feel good product compair it to the real deal on an airplane