By Erin Geiger Smith

NEW YORK, Jan 31 (Reuters) - The smartphone patent wars have lit up courtrooms around the world. Next up: the smartphone case wars.

The makers of protective cases that shield cell phones from coffee spills and sticky-fingered toddlers are entangled in countless lawsuits seeking to protect their designs.

The fights come as the mobile accessories market has gone upscale with some cases made by luxury designers costing more than the phones they cover. Some cases are billed as virtually destruction-proof, said to protect precious electronics from crushing blows or cresting waves.

Smartphones themselves are at the heart of a global patent fight, with Apple Inc battling South Korean giant Samsung Electronics Co over the design of the iPhone and iPad.

But now similar fights are escalating over what swaddles the gadgets, as the smartphone case market has become a roughly $1 billion annual industry, according to NPD Group, a market research firm. More than 100 million Apple and Samsung phones were shipped in the most recent quarter, making for more demand.

The damage claims in the case design fights are tiny compared with the smartphone wars, but the lawsuits could help spur a shakeout in a crowded market.

The biggest industry players sell their products at Apple and AT&T Inc retail stores, as well as at retailers such as Best Buy Co Inc. They have had success in getting court judgments against Chinese counterfeiters and domestic sellers of knock-offs, but the lawsuits involving one designer against another aren't as easily resolved.

Otter Products Inc, the maker of OtterBox cases, has become a frequent visitor to the courthouse.

The Colorado-based company has filed lawsuits in federal court in its home state against LifeProof, also known as Treefrog Developments Inc, and Mophie LLC for alleged patent infringement involving waterproof cases for iPhones, iPods and other devices. Mophie and LifeProof in court papers have denied the allegations.

Otterbox and Mophie did not respond to requests for comment. LifeProof declined to comment on pending litigation. Company spokesman Jonathan Wegner said, however, that LifeProof has programs in place to protect its own intellectual property.

The Ballistic Case Co, based in Florida, has also been a repeat plaintiff. The company has sued rivals Cell-Nerds LLC and Boxwave Corp for allegedly copying the look of its rugged "Shell Gel" series of cases, which feature a dotted back and come in an array of colors.

Designers invest significant resources in case styles and deserve legal protection, said Alan Weisberg, a Ballistic attorney.

The company has sold more than $12 million worth of Shell Gel cases, according to court documents, and they are available at major retailers. Both Cell-Nerds and Boxwave are smaller enterprises that sell cases online. The Shell Gel models are priced at about $35, while similar Cell-Nerds and Boxwave cases go for less than $10.

Earlier this month, a Miami federal judge allowed Ballistic's case against Cell-Nerds to move forward, while the Boxwave case is in its early stages in the same court. Ballistic claims it has so-called "trade dress rights" to the design of its cases and wants similar, rival products off the market.

An attorney for Cell-Nerds, Ury Fisher, said the company does not think Ballistic has accurately described its trade dress rights, and he noted that such cases are difficult to prove because plaintiffs have to show their product is readily recognizable to consumers.

An attorney for Boxwave did not respond to a request for comment.

For patent-based lawsuits to succeed, plaintiffs will need to prove another company is infringing their patents and may also have to show what is innovative about their designs and worthy of protection.

If found to infringe, some companies could be forced out of the market, said intellectual property attorney Christopher Carani of law firm McAndrews, Held & Malloy.

So far, however, the in-fighting among case designers does not show signs of slowing down the industry.

Casemakers have trotted out models they say are tricked out to withstand two tons of force or can be used to film movies underwater. At the recent Consumer Electronics Show in Las Vegas where new case designs seemed to be on display everywhere, one maker even showed off a case lined in soft orange putty that is designed to become "rock hard" if the phone is dropped.

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