As more people turn to mobile phones and tablets to access the Internet, advertising is making the move to mobile.

So Pasadena ad exchange OpenX has raised $22.5 million in an effort to expand its mobile advertising offerings.

Samsung Venture Investment Corp. led the round, which brings OpenX’s financing to $70 million in total. The funding will also be used for equipment expenditures, acquisitions and general expenses.

Tim Cadogan, the company’s chief executive, said Samsung has been a strategic partner since last year. But with the investment, OpenX can now take advantage of the Korean electronics conglomerate’s connections to mobile technology.

“A lot of our strategy is focused on taking our technology and making sure it works across any digitally connected screen,” Cadogan said. “Samsung is a very major player in those categories.”

OpenX was founded in 2008 as an ad exchange for buyers and sellers of web ads to make instant transactions. In the last year, the company has grown to 260 employees worldwide and recently moved into a 47,000-square-foot office space in Pasadena.

OpenX’s growth has fueled rumors that the now-profitable company is prepping for an initial public offering, though this latest round of financing suggests an IPO might not happen for some time.

Cadogan said the company is focused on expanding its services and continuing to grow its business.

“Last year we did some pretty significant growing, doubling the company in revenue and employees,” he said. “We want to scale up and think more about our mobile scalability. Samsung is a nice complement to our story and extending our DNA a little bit.”