LEDs Marching Towards General Lighting

As president of LED Lighting Technologies, Dr.Nisa Khan consults in the solid-state lighting industry and educates consumers about LED lighting. She has a bachelor’s degree in physics and mathematics, and master’s and Ph.D. degrees in electrical engineering. Email her at nisa.khan@iem-asset.com

Unquestionably, LEDs, as backlights, took the display industry’s center stage in 2010. The largest growth area, LCD-based television screens and electronic communication, and computing products engineered with overall, high-brightness LED (HBLED) lamps, exceeded $9 billion. Further, as LED lamp technologies advance, the solid-state, lighting-technology analysts and contributors anticipate multiple developments, and, additionally, the analysts blend statistics and development projections gained from accepted manufacturers and the scientific community to project future market trends.

So, what are they projecting now? LEDs for general lighting, or, to be specific — they’re envisaging LED-based lamps for household lighting as the next big wave.

The SSL industry has long touted LEDs for household lighting; however, to succeed, a retrofit lamp must be available for America’s most popular 60W incandescent lightbulb, the one that comes with an Edison-style screw base. Until recently, such lamps were unattainable at any major retail store, but, last November, Philips announced its12.5W, Edison-base, LED lamp (which is equal in output to its 60W incandescent lamp) as soon available at Home Depot stores.

I searched and found the lamps at my neighborhood Home Depot – just as advertised. Expectedly, Lowes has also announced that in early 2011, it will offer LED-lamp equivalents of Osram Sylvania’s 60W incandescent lightbulb (Fig. 1).

Both home-improvement stores say the LED lamps are presently available online.

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Are people buying such lamps in any appreciable quantity, and are they happy with the performance — and the nearly $40 cost?

Truth is, it will take some time to tell. First, a good number of users must invest in the lamps and, by doing so, experientially forecast whether the LED lamp retrofits are truly equivalent to the 60W incandescents (and CFLs). The sales results will also determine if the Edison-base, LED lamps’ claimed advantages — higher efficiency, longer lasting and eco-friendliness – validate the higher up-front cost.

Though shoppers will reach their own conclusions; here, I present a preliminary analysis of the Edison-base, Philips and Sylvania LED lamps and whether they offer any advantages over the current, incandescent and CFL lamps.

 

Philips’ 60W Retrofit LED lamp
Home Depot, the first major retailer to offer Philips’ AmbientLED 12.5W LED, 60W incandescent-replacement lamp, has always been bullish about LED lighting.
Philips designed its AmbientLED for such general lighting applications as overhead lights and desktop lamps.
As the name suggests, the $39.97, dimmable, AmbientLED lamp illuminates its ambient or surrounding space more effectively than traditional LED lamps. Comparably, the 60W, incandescent CFL equivalent, a non-dimmable version, costs less than $5 and consumes approximately 12W.
Philips’ AmbientLED’s light output is 800 lumens, which is comparable to the lumens produced by the ubiquitous 60W incandescent bulbs. And, although it’s not as omni-directional as incandescent or CFL lamps, the milestone LED bulb produces more multi-directional light than most current LED lamps that are commonly used in various niche applications.
The AmbientLED’s 2700° K color temperature is comparable to a standard, 60W incandescent bulb; both produce relatively warm, yellowish/white light. AmbientLED’s color rendering index (a relative measure of color accuracy) is 80, which is comparable a CFL lamp, but not as ideal as the incandescent. The AmbientLED’s lifespan — 25,000 hours – is significantly higher than incandescent and CFL lamp counterparts.
Better, an LED-based lamp doesn’t break easily and it’s both mercury and lead free – thus it’s more eco-friendly than CFLs.
The AmbientLED’s unconventional shape helps it surpass traditional LED bulbs in light dispersion, but its crowned dome allows light to emit from the sides, mostly, rather than from the top and bottom; thus,, it’s not as omni-directional as comparable incandescent and CFL lamps.
Further, the AmbientLED’s finned sides, included for cooling (thus extending the lifespan), handicap lateral illumination.
Adding to the unconventionality is the lamps’ French-vanilla-colored globe, a necessary characteristic that led Philips to imprint “White light when lit” on the lamp itself. The yellowish-cast globe results from Philips’ phosphor coating on the bulb’s interior surface. It converts the blue LED chip to a warm/white light. In most traditional white LED lamps, the manufacturers place the phosphor near the LED chip.

Sylvania’s 60W Retrofit LED lamp
Another encouraging indication is Osram Sylvania’s introduction of Sylvania’s $39.98, Ultra A-Line 12W LED lamp, now available at Lowes.com. As above, it’s designed to replace the conventional 60W incandescent lamp.
Sylvania’s Ultra A-Line, 12W LED lamp’s light output rating is 810 lumens; the color temperature is 2,700Ks and the CRI is 90. It lifespan matches Philips’ AmbientLED – approximately 25,000 hours. These values are similar, although, Sylvania’s CRI rate is significantly higher.
Sylvania’s LED lamp’s appearance is more conventional, although I suspect it, too, will be less omni-directional than the incandescent and CFL lamps (heat-sink components occupy the lamp’s bottom half).
Home Depot also sells a general-purpose 40W equivalent LED from Lighting Science Group, as well as an LED down light from Cree, plus various spotlights.

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CFL vs. LED
CFL recycling costs can elevate the full-life cost of each lamp. Minnesota’s recycling costs, for example, can average as much as $2 per unit. Further, retail buyers aren’t yet convinced of the CFLs benefits. The problems list includes outdoors unsuitability, slow starts, flickering, poor CRI and CCT, and usually, they don’t last as long as the package claims.
Such grievances create an opportunity for LED lamps, but I suspect the competition among the three technologies will continue. Over time, the lamp costs of both LED and CFL are expected to decrease, while the performance increases. Meanwhile, incandescents remain a very desirable and affordable household night light with one only one major drawback: energy inefficiency.