Late Friday afternoon, the California jury deliberating the patent infringement trial between Apple (NASDAQ:AAPL) and Samsung surprised court watchers by announcing a verdict.

Despite more than 100 pages of instructions from the judge — and weeks of conflicting, technical expert testimony — the jury arrived at its verdict after just three days of deliberations.

The nine-member jury found that Samsung had violated six Apple patents in its popular smartphones. Apple had initially sued the South Korean electronics giant in April 2011 claiming that it had violated seven key design and software patents, Bloomberg noted.

The jury awarded Apple more than $1.05 billion in damages, less than half of the $2.5 billion that the Cupertino, Calif.-based company had requested, but still a significant victory for the iPhone and iPad maker. Apple will likely ask the judge to increase the final award.

Samsung, by contrast, lost completely on its counterclaim that Apple had violated some of its patents.

The victory could mean additional sanctions against Samsung products, including, potentially, a ban on those found to infringe Apple’s patents.

Samsung shares fell sharply on the Korean Exchange, down more than 7% on news of the verdict, while Apple shares rose about 2% in early Monday morning trading in New York.

Sparring over patent infringement allegations has become commonplace in the electronics industry. In June, Apple obtained a court order halting sales of the Samsung Galaxy Nexus in the U.S. Additionally, Apple is currently battling a second round of patent claims from Google‘s (NASDAQ:GOOG) Motorola at the U.S. International Trade Commission.

Samsung decried the verdict as harmful to consumer choice and vowed to appeal.

Last week, a South Korean court found that both companies had violated the other’s patents in various products.