The Canon Pocketronic, the first handheld battery-powered electronic printing calculator, was developed at Texas Instruments as one of the earliest commercial applications of the integrated circuit. It was conceived in 1965 by TI founder Jack Kilby and TI president Patrick Haggerty as a way to exploit and popularize the integrated circuit developed at TI, which had been primarily used for military purposes up to that date. They turned the engineering of the product over to self-taught TI semiconductor engineer Jerry Merryman. In development the calculator was called the Cal-Tech.
The engineering took two years, and was eventually described in U.S. patent No. 3,819,921 applied for in September 1967 and finally granted on June 25, 1974. The patent entitled Miniature Electronic Calculator illustrated every aspect of the calculator, including the circuit designs of its three microprocessors.
Though the engineering was completed in 1967, the electronics were so advanced for the time that it took four years for a production model to be offered for sale. Canon had licensed the patent, and offered their Pocketronic for sale in Japan in 1970 and in the U.S. on April 14, 1971. The 4-function calculator that weighed 2 1/2 pounds and cost $150 was a huge success. 5 million pocket calculators were sold in the US in 1972 and sales continued to grow as the costs came down.