Wikipedia: Product innovation is defined as:
the development of new products, changes in design of established products, or use of new materials or components in the manufacture of established products
Policy Studies Institute, University of Westminster. “Small Firms’ Innovation” (PDF). Retrieved 27 May 2010.
To read: Eisenhardt, K. and Tabrizi, B. 1995. Accelerating adaptive processes: product innovation in the global computer industry. Administrative Science Quarterly, Vol. 40, pp.84-110.