AU Optronics Corp, the world's No.3 liquid crystal display maker, said it is working on a tie-up with a local LED chip designer to ensure its strength in the fast-growing LED-lit LCD TV market. AU Optronics said it was working on concrete details with Global Mixed-mode Technology Inc.. AU said a tie-up could pave the way for it to strengthen its cost competitiveness if it could secure a new generation of power-saving LED chips from GMT.