Apple looked in part to Sony for inspiration in designing its first iPhone, even having an internal designer produce "Sony-like" mock-ups of cell phones that carried the name of the Japanese electronics company, according to internal Apple documents submitted to a California court on Wednesday.

The documents were filed to the U.S. District Court in San Jose by lawyers for Samsung as part of an ongoing lawsuit with Apple over patent infringement. After months of in-court discussion and fighting, the two sides are scheduled to begin arguing their case in front of a jury on Monday.

A big part of the case revolves around allegations that some of Samsung's cell phones and tablet computers are too closely styled after Apple's products. With the recently filed documents, Samsung appears to be preparing to argue that Apple looked to other companies in designing its first cell phone and that such a practise is common in the consumer electronics marketplace.

The merits of this argument will be up to a jury to decide, but the documents do offer a fascinating look at some of Apple's design thinking almost a year before the iPhone was first revealed.

Apple founder Steve Jobs' admiration for Sony isn't a secret and the court filing appears to show that as part of the design process for the first iPhone, Apple asked one of its designers to answer the question: "What would Sony do?"

Samsung's court submission includes images produced by an Apple computer-aided design (CAD) system of a mock handset that borrows from Sony design elements of the time. They include a jog wheel, a combined control wheel and switch, that was used on Sony's Clie personal digital assistants.

A second submission includes a March 2006 email from Richard Howarth, a senior member of Apple's industrial design team, to Jonathan Ive, Apple's head of industrial design, concerning prototypes for the iPhone.

The email discusses mock-ups of a cell phone being prepared by Apple designer Shin Nishibori that Howarth refers to as "the sony-style chappy."

Included with the email were photographs of what apparently were 3D models of an early iPhone prototype and a phone based on Nishibori's design.

"He's able to achieve a much smaller-looking product with a much nicer shape to have next to your ear and in your pocket" wrote Howarth of the Nishibori design when compared to Apple's prototype of the moment.

While Nishibori apparently looked to Sony for inspiration, it's important to note that the resulting designs and mock-ups included in the court filing did not look like any actual Sony phones of the time.

Perhaps the two most striking aspects of the CAD mock-ups and one of the 3D models is that they look a lot more like the iPhone 4 than the original iPhone launched by Apple in 2007. The mock phone has a silver metal band running around the edge and a flat front and back.

The email was sent two weeks after Tony Fadell, then a senior executive in the iPod division, forwarded a BusinessWeek article to Apple's senior management, including Ive and Steve Jobs, in which the head of Sony's creative strategy unit was interviewed about the company's design. In the article, he also discussed the iPod's influence on Sony.

The case is 11-01846 in the U.S. District Court for the Northern District of California in San Jose.

Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is martyn_williams@idg.com