Hoya Corp. needs a more diverse, transparent board to help prevent "failures" such as the ¥94.4 billion purchase of Pentax Corp., said Yutaka Yamanaka, a grandson of the lens maker's founder.

Yamanaka, 33, on May 11 submitted a 15-point shareholder proposal that includes calls for disclosure of individual directors' pay and limits on concurrent board membership. Hoya's 2007 acquisition of camera and endoscope maker Pentax to expand its medical care business was "overpriced," he said.

"The proposal is aimed at establishing at Hoya a system capable of advancing new businesses such as ophthalmology medicines and research and development," Yamanaka, whose grandfather cofounded Japan's largest maker of optical glass in 1941, said in an interview Wednesday.

Japanese companies facing shareholder activist proposals fell to 19 last year, from a peak of 23 in 2007, as the global financial crisis drained funds, according to shareholder advisory group Glass, Lewis & Co.

Hoya, whose overseas investors own more than half of its outstanding stock, received no shareholder proposals last year.

Hoya has received multiple agenda items and plans to include them in the notice to its shareholders, company spokesman Naoji Ito said.

Yamanaka's proposals also seek an end to cumulative voting, which lets shareholders withhold votes from some nominees so they can cast multiple votes for others. The changes to the charter would require a two-thirds vote at Hoya's annual shareholders' meeting June 18.

"A 15-item shareholder proposal at a Japanese company is unheard of, " said Jun Frank, a director of Asian proxy research at Glass, Lewis.