Mobile phone commercially available handheld mobile phone. From 1983 to 2014, worldwide mobile phone subscriptions grew to over seven billion—enough to provide one for every person on Earth. In first quarter of 2016, the top smartphone developers worldwide were Samsung, Apple, and Huawei, with smartphone sales represented 78 percent of total mobile phone sales. For feature phones (or "dumbphones") , the largest were Samsung, Nokia, and Alcatel. A handheld mobile radio telephone service was envisioned in the early stages of radio engineering. In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with a very thin carbon microphone".
Mobile phone overuse potentially hazardous and can be "toxic" to the back of the eye. He states that an over exposure to blue violet light can lead to a greater risk of macular degeneration which is a leading cause of blindness. There are concerns that some mobile phone users incur considerable debt, and that mobile phones are being used to violate privacy and harass others. In particular, there is increasing evidence that mobile phones are being used as a tool by children to bully other children. There is a large amount of research on mobile phone use, and its positive and negative influence