The purported PlayStation phone next to the PSP Go

Sony's as-yet-unannounced PlayStation phone could be one of the worst-kept secrets in the technology industry.

Just a couple of days after images of what appears to be a PlayStation phone leaked on a Hong Kong forum, several more photos have been published on a Chinese Web site, called IT168.

The images appear to show a PlayStation phone in full working condition. According to Engadget, which first discovered the leak, the device in the images features a 4-inch touch display, 5-megapixel camera with an LED flash, a microSD slot, and a micro-USB port, among other features.

The smartphone in the images boasts slide-out PlayStation controls, including Sony's familiar D-pad and controller buttons. The smartphone and gaming device is branded with Sony Ericsson's Xperia logo.

The phone closely resembles devices featured in previous videos and images that have hit the Web.

Speculation abounds that Sony will unveil the device in February at Mobile World Congress. However, Sony Ericsson has been tight-lipped about the PlayStation phone. There's currently no telling what games the device will accommodate, and pricing and availability are a question mark. The company hasn't even offered any concrete clues that it will be announcing the smartphone anytime soon.

Regardless, Sony Computer Entertainment needs something to jump-start its ailing PSP business, and working with Sony Ericsson might be the best way to do it.

In August, the last month NPD reported sales figures, Sony sold just 79,400 PSP units, down nearly 50 percent from the 140,300 units it sold in August 2009. Moreover, GameStop said in November that the PSP has been "a disappointment" for the company at retail.

But that hasn't caused Sony to consider dumping the PSP entirely. Last month, Sony Computer Entertainment chief Kaz Hirai indicated that his company might soon offer a PSP with a touch screen.

"Depending on the game, there are ones where you can play perfectly well with a touch panel," Hirai told The New York Times. "But you can definitely play immersive games better with physical buttons and pads. I think there could be games where you're able to use both in combination."

Considering the leaked images show the PlayStation phone with both a touch panel and PSP controls, it's possible that Hirai was referencing the device in the interview.