Manufacturers have been forced to curtail production due an unstable supply of electricity from Tokyo Electric Power Co , which is imposing rolling blackouts and asking firms to conserve energy to help it cope with the power crunch.
The production interruptions at Ohara and rival optical glass maker Hoya Corp could impact production of digital cameras made by Canon , the world's largest producer, and others.
Ohara investor relations official Kyohei Yonekura said its Sagamihara factory in Kanagawa, west of Tokyo, was subject to the blackouts and that the company was also adjusting output in line with Tokyo Electric's request to lower power use.
"There is no timeline yet for returning to normal," he said, declining to elaborate on the extent to which production has been curtailed.
Hoya, Japan's No.2 maker of optical glass for single-lens reflex (SLR) cameras, said earlier this week that it too had suspended some production.
"We've switched off our (electric) furnaces, because we can't switch them off only when the power cuts come," said a Hoya spokeswoman. Hoya said it was continuing to operate gas-powered furnaces. (Reporting by Isabel Reynolds; Editing by Nathan Layne)