Light Bulb or Incandescent Light Bulb is one of the most famous inventions of Thomas Alva Edison. In 1878 he began serious research into developing a practical incandescent lamp. After many experiments with platinum and other metal filaments, Edison used a carbon filament. On October 22, 1879 Edison conducted his first successful test on the Light Bulb which lasted 13.5 hours. By Nov 4, 1879, he filed for a U.S. patent (granted as U.S. Patent 0,223,898) while still improving the bulb design. Several months after the patent was granted Edison and his team discovered that a carbonized bamboo filament could last over 1200 hours.
In Britain, the Edison and Swan companies merged into the Edison and Swan United Electric Company and in1881, the Savoy Theatre became the first public building in the world to be lit entirely by electric lights. From there onwards various changes in design and shape were made by different companies to bring efficiency.
Role of Light Bulb in the Improvement of human life