The increasing cost of energy， concerns about global warming due to CO2 emissions， and， more recently， supply issues resulting from natural disasters， such as the earthquake in Japan， are driving energy-reduction programs. Lighting， which represents up to 25 % of home energy usage， is a natural place to start when looking for ways to save on energy. The transition to newer， more efficient lighting technologies has already begun to replace incandescent bulbs. Compact-fluorescent lighting （CFL） and Solid-State Lighting （SSL）， two of the most popular alternatives to incandescent bulbs， are now commonplace in homes， offices， retail spaces， and along city streets and highways. A number of governments around the world have even passed measures to phase out incandescent bulbs entirely， so it is likely that CFLs and SSLs will continue to grow in popularity.