Kazuo Hirai is being criticized by a former Sony Corp director who said the company's chief executive officer is abandoning its traditional engineering focus.

Sony's electronics business is central to its long-term success, Tamotsu Iba, 79, a former chief financial officer and vice-chairman, wrote in a letter sent to management ealier this month. Iba, who sent two other missives earlier this year, wants Sony executives to address his questions about executive compensation and Hirai's leadership during a June 23 shareholder meeting.

Iba said Hirai's strategy runs counter to Sony's "Founding Prospectus", handwritten by co-founder Masaru Ibuka in 1946. The document describes "a stable workplace where engineers could work to their hearts' content in full consciousness of their joy in technology."