Light-emitting Diode Light Bulbs Research Articles

The “Green Lab”: Power Consumption by Commercial Light Bulbs

Going “green” is a slogan that is very contemporary, both with industry and in the political arena. Choosing more energy-efficient devices is one way homeowners can “go green.” A simple method is to change home lighting from hot incandescent bulbs to compact fluorescent lights (CFLs). But do they really save energy? How do their illuminations compare? Even if the CFLs are more energy efficient, they still add to our pollution problem because of the mercury inside them. Light-emitting diodes (LEDs) could be the answer, but they are not available at our local stores. Can LEDs be made to screw right into a standard socket? How expensive are they? What are the power consumptions of so-called “60-W” and “100-W” CFL and LED light bulbs? These are the questions that are answered during this lab activity. Students measure the voltage and current for each of the three types of bulbs, and then calculate the electrical power required by each. An optional experiment is to set the light outputs of each bulb so they are equal in intensity, and then determine the power consumed. While not practical in the home, this experiment gives students an understanding of value for their buck.

Indoor Lighting Facilities

According to statistical documents regarding building construction floor space from the Ministry of Land, Infrastructure, Transport and Tourism, the construction floor space of all buildings was 115,490,000 m2, which was 26.6% less than the previous year and was the third year in a row for decline. Even for office space, there was a 20.0% decrease versus the previous year. In 2009, the rebuilding of historical buildings in major metropolitan areas continued, and efforts to reduce greenhouse gases also accelerated. The efficient use of office lighting was established through initial illuminance correction control using sensors, control for using daytime light, and control through motion sensors. Furthermore, in line with JIS standards revisions, lighting facilities that control discomfort glare have started to be implemented. Light emitting diode (LED) lighting is now being used in various types of facilities, including exhibition halls, multipurpose halls, conference rooms, and religious buildings. Even in art galleries, which demand high color rendering, LED lighting has started to be used for exhibits. In hospitals and retirement homes, there continues to be a strong consciousness of energy efficiency. The use of LEDs is increasing even for environmental lighting applications, and chandeliers and LED lightbulb downlights controlled by motion sensors have started to be employed. In 2009, the number of new theaters and halls constructed was very small. With a total number of six plus some small halls, it was the lowest number of new buildings in recent years. On the other hand, there is a feeling that all existing theaters and halls have gone ahead and performed renovations. Countrywide, forty-five facilities performed renovation work, which was a 50% increase over the previous year and was the highest number of renovations in recent years. In shops and business facilities, LED lighting has traditionally been often used as store fixture lighting and wall accent lighting. However, improvements in output and color rendering and the diversification of product types have progressed and full scale introduction into product presentation is now possible. In the accommodation, food and drink, and service industries, the use of LEDs as light sources is increasing in positions that require high color rendering, and renovations that emphasize energy efficiency are being introduced. Furthermore, LEDs are being employed for room lighting to provide modulated lighting that is suitable for when guests awaken. In the residential building industry, LED lighting fixtures are increasingly employed for high ceiling areas and underwater applications in order to utilize their greater control of the distribution of luminous intensity.

Light Sources and Lighting Circuits

According to machinery statistics of the Ministry of Economy, Trade and Industry, the quantity of electric lamps produced in Japan was 613,000,000 (68.1% compared to the previous year). Of these, 73,000,000 were general lamps (88.1% compared to the previous year) and 32,000,000 were halogen lamps (79.3% compared to the previous year). The number of fluorescent lamps produced was 627,000,000 (72.9% compared to the previous year), and the number of general fluorescent lamps excluding backlights was 240,000,000 (86.0% compared to the previous year). Furthermore, the number of HID lamps produced was 7,600,000 (75.6% compared to the previous year). On the other hand, when looking at the sales amounts compared to the previous year, the results for general lighting electric lamps, halogen lamps, general fluorescent lamps, backlights, and HID lamps were 88.5%, 87.7%, 91.6%, 49.1%, and 76.4%, respectively. For compact fluorescent lamps, which are included within the numbers for general fluorescent lamps, sales amounts were 92.7% compared to the previous year, which was a large drop from 137.3% in 2008. The main causes mentioned for the decreases in production numbers and sales volume for these mainstream lamps are generally the economic recession and the rise of LEDs, a new light source that is now being used in the general lighting field. The main exhibition domestically was Lighting Fair 2009 held in March at Tokyo Big Sight. Internationally, it was Light Fair held in New York City in May. Although some new types of and research results for incandescent electric lamps are seen, their use and production continues to be stopped worldwide due to their low luminescence efficiency. In particular, the EUP directive (a directive related to energy using products and now named the ERP directive) was enacted in Europe in September. The sales of white diffused and clear types of incandescent electric lamps of 100 W or more and halogen lamps are prohibited. In Japan as well, major manufacturers continue to stop or reduce production of incandescent electric lamps. With fluorescent lamps, development into energy efficiency and longer life is healthy and new product releases of compact fluorescent lamps and ring fluorescent lamps are seen. Furthermore, the issue of reducing the amount of enclosed mercury remains and the IEC is continuing validity investigations of measurement methods. For light emitting diode (LED) light sources, 2009 was the year they saw full-fledged commercial viability and it may be remembered as the year that LEDs started to receive attention from average consumers. The luminescence efficiency of individual chips was reported to have reached 250 lm/W at the research level. In the Japanese production industry, the current market price of LED light bulbs quickly dropped to almost a third between the beginning and the end of the year. This drop is believed to be due to competition between the main existing light source manufacturers and manufacturers newly entering the market, the development and market introduction of LED products, and the flow of manufacturing processes to developing countries with cheap labor costs. In high-intensity discharge (HID) lamp field, product development and technological research related to ceramic metal halide lamps is as popular as ever. With increased emphasis on environmental conservation, mercury-free ceramic metal halide lamps are also being announced as reference exhibits at exhibitions. While reports regarding HID lamps cover fundamental research, reports of applications for growing plants are also being seen. There are also many reports about other types discharge lamps, including electrodeless lamps that use inductively-coupled mercury, microwave discharge lamps, and excimer discharge lamps. Furthermore, there are many reports about application examples of the nanotechnology as a new light source. With regard to lighting circuits, (…)

The Switch Is On

This article reports on changes in lightbulb standards in the U.S. and how different kinds of lightbulbs can save energy while maintaining light output. An energy bill passed by the U.S. Congress in 2006 set requirements to make lightbulbs more efficient by 2012 and 2014. The article also discusses lightbulb construction, technology, and manufacturers. Fluorescent, incandescent, compact fluorescent, and light-emitting diode lightbulbs are compared as well.

LEDs and Home Lighting Technology

ONE OF the best parts about writing this column is that I have to learn something before I can write about it. That's the fun part. This time, I had to learn about home illumination. Specifically, I wanted to see if LED (light-emitting diode) technology was a feasible option for home lighting. Most of the sources I consulted predicted that LED home lighting was 10 years in the future. Because I think technology moves faster than this, I'm predicting three years. Obviously, I will report my findings, but first I think a primer on light, color, and the various technologies used to illuminate our homes is in order. There are numerous technologies used in home lighting, including tungsten incandescent, quartz halogen, fluorescent, and LED. Low-pressure sodium is more common in such outdoor applications as street lighting. These various technologies have distinctive advantages and disadvantages. The most familiar have been around for more than 100 years, and they are inexpensive. But a major disadvantage is that they are inefficient and waste a lot of energy in the form of heat. In addition, incandescent bulbs have a short lifetime. Incidentally, the regular screw-in base is called the Edison base, which can be useful to know for online searching. Fluorescent lighting is a great deal more efficient than incandescent lighting, but the tubes are fragile, require ballasts that sometimes hum, and contain mercury. Newer compact fluorescents eliminate many of the disadvantages of the large fluorescent tubes. Halogens are more efficient than incandescents but share many of their disadvantages. The newest kid on the block, LEDs are 10-20 times more efficient than incandescents, so they use substantially less electricity. LEDs are also rugged and have a lifetime of more than 100,000 hours. Because I get tired of changing light bulbs, this is a very attractive feature. LEDs are small, so they must be combined into arrays or clusters. And because LEDs are low-voltage devices, using them in home lighting requires a power supply. In an LED light bulb, this power supply is built into the base of the bulb. White LEDs have generally not been available, but manufacturers are working feverishly to change that. We have all grown used to buying light bulbs with various wattage ratings, such as a 40-watt or 60-watt bulb. Light output, however, is measured not in watts but in lumens. Don't ask for a simple definition of a lumen, because it gets complicated. But a standard 40-watt bulb produces about 390 lumens, while a 75-watt bulb produces about 1,055 lumens. (The figures are for Sylvania Double Life Soft White bulbs.) The efficiency of a light source is measured in lumens per watt. According to references in Wikipedia, the lighting technologies mentioned above have the following efficiency ratings in lumens/watt: 40-watt tungsten, 12.6; quartz halogen, 24; fluorescent, 56; LED, 131; and low-pressure sodium, 200. All light is not the same color. The sun at noon is nearly perfect light because all the colors of the spectrum are evenly present. Home lighting merely approximates There are several descriptors that manufacturers of home lighting use to describe the color of the light produced. The four most common are soft white, cool white, warm white, and sunlight. I believe that soft white means that the light is evenly dispersed from the bulb. …