In one of the largest-ever funding rounds for lighting, Luminus Devices said Monday it has raised $72 million in venture capital. 


The cash brings Billerica, Mass.-based Luminus' total funding to a whopping $139 million and represents "certainly the largest solid-state lighting" funding so far, according to Greentech Media analyst Eric Wesoff. But the round also brings questions from Wesoff and other industry experts, who wonder how Luminus will manage to execute a profitable exit strategy.

Contributors to Luminus’ fifth round include lead investor Braemar Energy Ventures, as well as CMEA Ventures, Paladin Capital Group and all of the startup's previous backers, such as Battery Ventures, Argonaut Partners and Stata Venture Partners.

With Monday’s round, Luminus’ total surpasses the $77 million light-emitting-diode component company Cree (NSDQ: CREE) paid to acquire LED Lighting Fixtures, a manufacturer of LED fixtures, earlier this month. That statement holds true even when factoring in the additional $26.4 million Cree will dole out to LED Lighting Fixtures if the company reaches certain milestones. (See Cree to Buy Firm Founded by Its Former Execs and press release.)

Such a hefty sum might seem strange to those familiar with Luminus Devices’ history; the company has previously focused mainly on lighting for televisions and displays, a much smaller potential market than that targeted by LED Lighting Fixtures. Luminus said it will use its fifth round to expand its market to a broader array of applications.

Although the company didn't say which specific markets it will target, the "opportunities for solid-state lighting range from general commercial and consumer lighting to specialty applications such as medical, entertainment and homeland security, to name a few," according to a company press release.

But with all that capital, asks Wesoff, what is Luminus' exit strategy?

Large lighting IPOs are rare. In its December IPO, Orion Energy Systems raised $100 million. An equivalent IPO still wouldn't be enough to bring Luminus investors a return on their bets. Still, Wesoff said Luminus Devices is a likely acquisition target for the few large lighting companies, such as Philips Lighting, Osram Sylvania and General Electric.

Luminus is “leveraging once-niche-y applications to try to go after general illumination and lighting," Wesoff said. "They have great technology and great sales, but that's a very large financing round; it's a crazy amount of funding."

A number of other lighting deals have come out in the last few months, though those deals have generally been much smaller. In February, Lumenergi, which makes dimmable fluorescent lighting, raised $7.5 million from Low Carbon Accelerator. Albeo, which makes commercial and industrial LED systems, raised $1.5 million from Green Spark Ventures