(Reuters) - The takeover battle for Coherent Inc intensified on Thursday after optical components maker II-VI Inc raised its bid for the laser maker to $7 billion, trumping a rival offer from Apple supplier Lumentum Holdings. Coherent supplies laser-based equipment used in making organic light-emitting diode (OLED) displays, which are becoming a popular choice for smartphones and high-end televisions due to their energy efficiency and better contrast and higher refresh rates. Coherent said on Thursday that under II-VI’s revised bid, shareholders would receive $220 in cash and 0.91 of a II-VI share for each share they own. Lumentum raised its offer to $6.9 billion on Wednesday. Coherent was put into play after Lumentum, a supplier of 3D sensors used in iPhone’s Face ID, offered $5.7 billion for the company in January, triggering rival bids from MKS Instruments Inc and II-VI Inc last month. Since then Lumentum and II-VI have been caught up in a fierce bidding war as the acquisition would help expand their foot print in an industry set to benefit from 5G rollouts and laser-based technology in everything from phones to cars. Coherent said it was in favor of II-VI’s superior offer. II-VI, whose name refers to the elements in group II and VI of the Periodic Table that are used in making infrared optical crystalline compounds, bought Apple supplier Finisar Corp for about $3.2 billion in 2018. Shares of Coherent, which have gained about 69% since Lumentum’s first offer, were up 3% on Thursday. Shares of II-VI and Lumentum were down about 2% each.