Apple has filed a new US patent lawsuit against Samsung over the Galaxy S III, Verizon Galaxy S III, Galaxy Note and Galaxy Note 10.1, after its major victory in a San Jose court last month.
In February, Apple alleged that at least 17 Samsung products infringed its patents. It added four more products to the list in a submission to the San Jose federal court on Friday.
The new filing came after a separate jury awarded Apple more than $1 billion in damages when it found that Samsung had copied critical features of the hugely popular iPhone and iPad last month.
Samsung representatives did not immediately respond to requests for comment.
Android losing favour?
According to industry watchers, some phone makers have begun quietly exploring alternatives to the Android operating system implicated in the Samsung-Apple ruling.
Samsung was found to have infringed six of seven Apple patents, including technology that recognises whether one or two fingers are on the screen, the front surface of the phone and the design of screen icons, which is a clear reference to Google's technology.
After the verdict, Google said that most of the patents involved "don't relate to the core Android operating system".
The ruling could lead to sales bans and high licensing fees for Samsung, and could also affect other Android smartphone vendors like HTC, ZTE, and Sony.
Huawei, Sony, Lenovo and ZTE - which all use Android extensively - told Reuters they were continuing to bet on the Google's platform despite the ruling.
But behind closed doors, companies were looking at alternative routes should the ruling impact ripple wider out, several industry insiders said.
"Today, all Android vendors are considering their software options," said Pete Cunningham, an analyst at research firm Canalys.
Samsung, which has used a number of platforms but now mostly uses Android, announced a new phone running on Microsoft's new Windows Phone 8 software at a consumer technology conference on Wednesday, sneaking ahead of a hotly anticipated launch of a Nokia-Windows phone due next week.
Shares in Nokia, which has partnered with Windows and is its main user, jumped after the Samsung ruling on expectations it might be a safer legal bet than Android makers.
Analysts said Samsung's Windows Phone 8 launch should be interpreted as muscle-flexing.
But Malik Saadi, analyst at research firm Informa, said it was not a firm move away from Android as the model would likely struggle to stand out even among the other Windows phones.
Android was used in 68 percent of all smartphones sold last quarter, with Samsung making almost half of them, while Microsoft had 3 percent market share.
Despite its small market share, Windows Phone is still the largest alternative to Android as Apple and Blackberry maker RIM (RIM.TO) have not made their platforms available for other handset makers.
At the same time, vendors are pretty much stuck with Android as Windows is way behind in terms of applications on offer, offering just 100,000 apps against half a million each on Android and Apple.
"Microsoft needs to create a developer environment for the Window Phone, which is growing, but still trails behind the others," said Roberta Cozza, analyst at Gartner.
The balance of power is unlikely to shift quickly as this season's new phones were all made before the ruling.
Sony launched three Android phones this week at IFA, Europe's largest consumer electronics fair. Chinese phone maker Huawei launched four.
"We have made our choice," said Lars-Christian Weissewange, vice president at Huawei's phone unit, adding that consumers were making the platform choice for them by picking Android phones. Sony said the ruling was not impacting its business.
"This is probably not impacting consumer thinking," Gianfranco Lanci, chief of Lenovo's European operations, said on sidelines of the conference.
(Reporting By Tarmo Virki and Andrew Longstreth; Editing by Richard Chang, Jane Barrett and Janet McBride)