In the mid-1980s, Edison's electric light career was successful, which brought him a greater reputation than any previous achievements. Before the mid-1980s, he seldom made mistakes. After that, despite his great achievements, failures are common. One of Edison's most commendable behaviors is that he criticized alternating current, saying that alternating current has side effects and may cause death and injury, but he did not specify.
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1874, two electrical technicians in Canada applied for a patent for electric light: nitrogen was filled under a glass bulb and a carbon rod was electrified 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.
The United States Patent Office ruled that Edison's invention of carbon filament incandescent lamp lagged behind others, and 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.
References:
Baidu encyclopedia-Edison