Panasonic earlier unveiled a prototype of the world's largest organic light-emitting display screen in a show of technological one-upmanship with its South Korean rivals Samsung and LG Electronics. Sony, which is cooperating with Panasonic in OLED technology, unwrapped on Monday its own 56-inch ultra high-definition model. ( Read More : Sony, Panasonic Face 2, 3 Years of 'Poor Profitability' ) Tsuga, who heads Japan's biggest commercial employer with 300,000 staff, is also pursuing a niche strategy and bolstering the company's appliance business in a bid to capture more profitable markets while the likes of Samsung and Apple slug it out in mass-market consumer electronics. The executive has promised to deliver the details of the revival plan by the end of March, when he plans to reorganize 88 businesses into 56 units. So far he has said that businesses that fail to achieve a 5 percent operating margin within two years will be shuttered or sold.