When was the first touchscreen laptop available to the public?

Designed in 1979 by a Briton, William Moggridge, for Grid Systems Corporation, the Grid Compass was one fifth the weight of any model equivalent in performance and was used by NASA on the space shuttle program in the early 1980's. It had a 340K byte bubble memory lap-top computer with die-cast magnesium case and folding electroluminescent graphics display screen.