Osram is grappling with declining auto sales in China and difficulties faced by smartphone makers Apple and Samsung Electronics, as well as weakening demand for general lighting.

First-quarter revenue dropped 15 percent to 828 million euros ($942 million) compared with 939 million euros a year earlier, Osram said, adding it expected an adjusted core earnings (EBITDA) margin of 11.3 percent versus 18.5 percent a year earlier.

All three of its divisions performed badly in the quarter, with sales at its Opto Semiconductors unit - once a top performer - down 16.9 percent.

The company said it would restructure the unit to help it reach its full-year guidance of flat to moderate comparable revenue growth and an adjusted EBITDA margin of 12 to 14 percent.

But it warned achieving its guidance would hinge on a revival of orders in the coming months.

"Foremost, the ongoing trade conflicts, the weak growth in China and the general political uncertainties had a negative impact. As a result, visibility for the quarters ahead will remain significantly low," Osram said.

Shares in Osram, which have more than halved in value over the past year, were trading down 1.2 percent by 0850 GMT.

Osram was floated in 2013 by Siemens, the industrial conglomerate, which sold its last shares in the business in late 2017. Osram has been the subject of speculation that a strategic investor may buy a stake.

Osram is due to publish full financial figures for its first quarter on Feb. 7.

(Reporting by Caroline Copley; Editing by Mark Potter and Maria Sheahan)