SAN JOSE, Calif.--Apple Inc.'s (AAPL) case against Samsung Electronics Co. (005930.SE) moved closer to its final stages Friday, as the iPhone maker presented its final witnesses to argue that it had not infringed the Korean tech giant's patents. Apple spent Friday bringing up a mix of people to discuss technical details of the patents Samsung claims are being violated, and to rebut witness testimony as well. Apple brought Hyong Kim and Edward Knightly, both engineering and technology professors, who discussed Samsung's patents, describing how the patents could even be invalid in some cases, and how Apple's own devices don't infringe them in others. Though the Cupertino, Calif., company started the legal battle with its lawsuit filing against Samsung last year, Samsung has fired back by accusing Apple of infringing its patents, such as those for handling photographs in an email and one regarding wireless transmissions. One flashpoint in the case has erupted outside the courtroom, in an ongoing debate within the technology industry about patents that are part of agreed-upon standards, such as 3G wireless technology. Standards bodies allow companies to claim their patents are essential for creating products that use a standard, but in doing so the companies also agree to license those patents in a fair, reasonable and nondiscriminatory way. Apple has alleged that Samsung has failed to follow that agreement, leading to inquiries by regulators in Europe, and comments from those in the U.S. as well. As part of its argument in court, Apple brought Michael Walker, a former chairman of a European telecommunications standards body, to the stand to discuss Samsung's alleged failure to disclose its patents to standards bodies in a reasonable time frame. One argument Apple asserted in its numerous lawsuits with Samsung around the globe has been that by not claiming its patents in a reasonable time, Samsung had forfeited its place as part of that standard. Samsung lawyers said that wasn't the case. In its offensive, Apple also called Richard Donaldson, a former patent counsel at Texas Instruments Inc. (TXN), to the stand to argue that Samsung's licensing demands of 2.4% of the net sale of a device was unreasonable. He noted that would work out to roughly $14, more than the $10 Apple pays for its wireless chips affected by the patent. Mr. Donaldson also said he was not aware of any licensees paying Samsung for its wireless patent portfolio. Not all of Apple's testimony was an intricate discussion of patents and patent agreements. Apple also called Susan Kare, a independent graphics specialist who created images used in Apple's original Macintosh computer, to the stand for the second time in the trial. In her testimony, Ms. Kare was asked about arguments made by Jeeyuen Wang, a Samsung designer who worked on some of the products accused of infringing Apple's designs. Ms. Wang had said in particular that although the application icons on its devices bore some resemblance to the ones Apple uses, they weren't copies. Instead, Ms. Wang said she used images that were fairly obvious objects. For example, she said, Samsung used the image of a phone receiver for its phone application because other icons, such as the image of a cell phone with an antenna or a smartphone, had confused its customers. Ms. Wang also said icons generally needed a square around them to make tapping them easier. Ms. Kare disagreed, arguing that there are many images that can be used to convey an application's abilities. She also said many phones have successfully displayed icons without squares around them. As the arguments wind down, Apple and Samsung will be handing the case over to jurors who at times have had trouble staying awake during more technical discussions, and some members of whom may not understand the intricacies of the issues. Lucy Koh, the presiding judge in the case, has expressed frustration with both Apple and Samsung as the two companies have filed hundreds of documents as part of the case. On Thursday, Judge Koh asked both sides to have their respective chief executives meet once more to discuss possible settlements in order to avoid jury deliberations. Apple and Samsung have locked horns in countries around the globe, seeking injunctions to either slow one another's sales or take some share of their profits. Presentation of arguments at the trial, which began July 30, is expected to end Friday. Write to Ian Sherr at ian.sherr@dowjones.com Subscribe to WSJ: http://online.wsj.com?mod=djnwires