The digital Watch

A digital display simply shows the time as a number, e.g., 12:08 instead of a short hand pointing towards the number 12 and a long hand 8/60 of the way round the dial. The digits are usually shown as a seven-segment display.
The first digital mechanical pocket watches appeared in late 19th century. In the 1920s, the first digital mechanical wristwatches appeared.
The first digital electronic watch, a Pulsar LED prototype in 1970, was developed jointly by Hamilton Watch Company and Electro-Data, founded by George H. Thiess. John Bergey, the head of Hamilton's Pulsar division, said that he was inspired to make a digital timepiece by the then-futuristic digital clock that Hamilton themselves made for the 1968 science fiction film 2001: A Space Odyssey. On April 4, 1972, the Pulsar was finally ready, made in 18-carat gold and sold for $2,100. It had a red light-emitting diode (LED) display.
Digital LED watches were very expensive and out of reach to the common consumer until 1975, when Texas Instruments started to mass produce LED watches inside a plastic case. These watches, which first retailed for only $20, reduced to $10 in 1976, saw Pulsar lose $6 million and the Pulsar brand sold to Seiko.
An early LED watch that was rather problematic was The Black Watch made and sold by British company Sinclair Research in 1975. This was only sold for a few years, as production problems and returned (faulty) product forced the company to cease production.
Most watches with LED displays required that the user press a button to see the time displayed for a few seconds, because LEDs used so much power that they could not be kept operating continuously. Usually the LED display color would be red. Watches with LED displays were popular for a few years, but soon the LED displays were superseded by liquid crystal displays (LCDs), which used less battery power and were much more convenient in use, with the display always visible and no need to push a button before seeing the time. Only in darkness you had to press a button to lit the display with a tiny light bulb, later illuminating LEDs. The first LCD watch with a six-digit LCD was the 1973 Seiko 06LC, although various forms of early LCD watches with a four-digit display were marketed as early as 1972 including the 1972 Gruen Teletime LCD Watch, and the Cox Electronic Systems Quarza. In Switzerland, Ebauches Electronic SA presented a prototype eight-digit LCD wristwatch showing time and date at the MUBA Fair, Basle, in March 1973, using a Twisted Nematic LCD manufactured by Brown, Boveri & Cie, Switzerland, which became the supplier of LCDs to Casio for theCASIOTRON watch in 1974.