Vu1, a Seattle-based developer of energy-efficient light bulbs that don’t use mercury, announced today that it has raised $500,000 from Full Spectrum Capital as part of a convertible debt financing agreement. Full Spectrum could choose to loan as much as $7 million. Vu1 also announced the resignation of CEO and director David Grieger, who joined the company in January after 20 years at Tacoma, WA-based Russell Investments, according to Vu1’s website. He is being replaced as CEO by Full Spectrum’s R. Gale Sellers who is also Vu1’s president and founder.