In 1985, the term "JumboTron" was coined by Sony for its large-scale video board. The JumboTron was the brand name for the large-scale video boards originally manufactured by Sony, and is recognized as one of the largest non-projection video displays ever manufactured. Sony creative director Yasuo Kuroki, who previously helped create the Walkman, is credited with the development of the JumboTron. It was introduced at the Expo '85 held in May 1985 at Tsukuba, Ibaraki. It had a display resolution of 450,000 pixels, using a new proprietary Sony technology called the Trini-lite. It was a microprocessor-based light bulb developed by one of Kuroki's colleagues, chief Betamax engineer Yuji Watanabe. Trini-lite technology allowed screen clarity and computer control, laying the foundation for the first Sony Jumbotrons.