1854, Henry Gaubert, a German watchmaker who immigrated to the United States, made the first practical electric lamp with carbonized bamboo wire in a vacuum glass bottle, which lasted for 400 hours, but he did not apply for a patent in time. 1860, joseph swan, an Englishman, also made a carbon filament lamp, but he failed to obtain a good vacuum environment to make the carbon filament work for a long time. It was not until 1878 that the vacuum technology in Britain developed to the required level that he invented a light bulb powered by carbon wire under vacuum and obtained a British patent. Swan's own house is the first private house with electricity lighting in Britain.
1874, two electrical technicians in Canada applied for a patent for electric light: nitrogen was filled under a glass bulb and charged carbon rods were used to emit light, but they did not have enough financial resources to continue to improve this invention, so they sold the patent to Edison in 1875. Edison tried to improve the filament after purchasing the patent, and finally made a carbonized bamboo filament lamp that could last for 1200 hours in 1880.
However, after the US Patent Office ruled that Edison invented the carbon filament incandescent lamp, the patent was invalid. After years of litigation, Henry Goebbels won the patent, and finally Edison bought the patent from Goebbels poor widow. In Britain, Swan accused Edison of patent infringement. Later, they settled out of court and set up a joint venture company in Britain on 1883. Swan later sold his shares and patents to Edison. [2][3]
At the beginning of the 20th century, carbonized filament was replaced by tungsten filament, and tungsten filament incandescent lamp is still in use today.
1938, the fluorescent lamp was born. 1998 white LED lamp was born.