Jon Martis, Microchip Technology, www.microchip.com 

There is no doubt that traditional incandescent bulbs will be displaced by high-efficacy light sources. Government agencies throughout the world have dictated this reality. Solid-State Lighting (SSL) technology will not immediately replace incandescent lighting; however, it is expected to be the lighting technology of choice within 10 years. The evolution of the lighting industry will likely result from additional advancements in Light Emitting Diode (LED) technology, the education of lighting engineers, and consumer acceptance of new illumination concepts. Government agencies, concerned with energy demand, are legislating the extinction of traditional incandescent bulbs.

In October 2005, California’s Title 24 became one of the first regulations to start eliminating traditional bulbs. Likewise, Australia will phase out incandescent bulbs by 2010; Canada by 2012; and the United States by 2020. These mandates have forced manufacturers to pursue Compact Fluorescent Lamp (CFL) replacement bulbs. CFL bulbs have evolved as direct replacements using existing Edison sockets. However, issues associated with CFL bulbs prevent them from being truly compatible replacements. Bulb orientation, ambient operating temperature, trace amounts of mercury and the color temperature of the emitted light are some of these issues. SSL shares some of these same issues, but with SSL technology in its infancy, these concerns can be conquered.

Short life expectancies of incandescents demand an easy method of replacement. SSL designers understand that traditional methods are not suited for new technologies. Lighting manufacturers are expected to implement approaches with the light fixture and source integrated, eliminating the Edison socket. Properly designed, SSL-integrated fixtures do not require light source replacement—at least not for a long, long time. LED efficacy is expected to surpass the efficacy of all other light sources twofold, with very competitive pricing. In the near future, when the SSL-integrated model of lighting is adopted, SSL will inevitably displace both traditional-incandescent and CFL bulbs. 

Joe DeNicholas, National Semiconductor, www.national.com

Solid-state lighting will replace traditional incandescent sources in particular applications within a decade.  First of all, they are perfect for replacing lower wattage MR-11 and MR-16 fixtures, which currently use low efficiency halogen incandescent sources.  Secondly, LEDs can perform some functions much more easily than fluorescent sources, like dimming and programmable color or whitepoint (CCT).  While CFL sources do exist that are dimmable and color tunable, LEDs are better performing in these areas and will continue to improve.  Thirdly, the cost of LEDs is on an exponential decline, and efficiency is increasing faster than any other light source, and will soon challenge even linear fluorescent tubes when total fixture efficiency (the only efficiency specification that really matters) is taken into account.  Fourthly, LED lifetime and lumen maintenance is better than expected, and will eventually represent the best-in-class light source.  

Lastly, legislation around the world is forcing the use of more efficient sources.  While CFL lamps use only milligrams of mercury, their disposal in landfills can contaminate groundwater.  Proper disposal of CFL lamps will be impossible to monitor and regulate.  While cost, thermal issues, and intellectual property battles currently hinder the adoption of LED technology, these issues will be worked out over time resulting in the LED being a viable high efficiency light source. 

Bernie Weir, ON Semiconductor, www.onsemi.com 

Incandescent bulbs, first commercialized in the late 1880’s, are becoming displaced. While their upfront cost is low; their operating cost is high due to their low efficacy (13-15 lumen/W for a 60W A-lamp) and short lifetime. As part of the 2007 US Clean Energy Act, most low efficacy incandescent general service bulbs will be banned by 2014. Compact fluorescent lamps (CFLs) contend with incandescent bulbs by offering improved efficacy coupled with longer lifetime thus offering consumers an alternative that can reduce their lighting energy cost by a factor of 3-5. Unfortunately, CFLs are not a panacea; they contain toxic mercury and many lamps on the market have low power factor (0.5-0.6 typical) and cannot operate with standard dimmers.  While low power factor does not impact the residential consumer, it does impact the distribution through the grid as the utility must produce almost 2x the power to deal with the apparent power load caused by the low power factor.  Not withstanding CFL adoption, the US Department of Energy estimates that 971 million incandescent bulbs will be in use in the US in 2010. 

Phosphor-conversion white LEDs have made great leaps over the last few years in terms of light output (lumens) and efficacy and the best-in-class LEDs on the market have efficacies on par with linear fluorescent lamp tubes.  LEDs do have unique properties; they are inherently low voltage devices requiring constant current drive, their light output is directional, and while they are efficient, their power dissipation is concentrated.  These attributes pose numerous challenges in creating LED based solutions that address the thermal, optical, as well as electrical drive requirements while attaining the long lifetimes that LEDs can achieve.  To encourage alternatives to CFL, the US government has created the L-Prize which sets a $10M prize for the first manufacturer offering an LED based 60W incandescent A19 lamp replacement that meets a strict set of performance criteria.  Compared to incandescent bulbs, high brightness LEDs are still in their infancy and are poised to make a big splash in the general lighting market just as they have been replaced incandescent bulbs in traffic signal and automotive applications over the last few years.