SAN FRANCISCO — Google on Monday announced a partnership with the Luxottica Group, the largest eyeglass company in the world, to design, manufacture and distribute frames for Google Glass, the Internet-connected eyewear.

The announcement is Google’s biggest effort yet to make Glass attractive and available to mainstream consumers as it prepares to sell it more widely later this year. In January, Google announced that it would partner with VSP, the nation’s biggest optical health insurance provider, to offer subsidized frames and prescription lenses for Glass.

Yet Google has struggled to gain mainstream acceptance for Glass. Certain bars have barred patrons from wearing it, lawmakers are grappling with whether to allow people to wear it while driving, and a man in Ohio was removed from a theater and interrogated by Homeland Security agents after wearing Glass to a movie. Less conspicuous types of wearable computers, like wristbands, are catching on more quickly.

Though Google is expanding into the device business, its expertise is as a software builder, not as a hardware manufacturer, retailer or fashion designer.