California District Court Judge Lucy Koh Friday enjoined the Android Samsung Galaxy Nexus smartphone that Google co-developed because, she said, Apple is likely to prove it at trial that it infringes four Apple patents including the Google nose-pulling Siri unified search patent.

Without a preliminary injunction, she said in her 101-page ruling, Apple was “likely to lose substantial market share in the smartphone market and to lose substantial downstream sales of future smartphone purchases and tag- along products.”

The harm to Samsung is outweighed by the “irreparable harm” to Apple, she said, but there’s still a hearing scheduled for Monday regarding a Samsung appeal and try for a stay.

The threat to Samsung is serious. It remains to be seen whether it’s the thermonuclear bomb Steve Jobs wanted to drop on Android.

According to IDC Samsung owns 29.1% of the global smartphone market to Apple’s 24.2%.

The eight-moth-old Nexus phone is pure unvarnished Android with no OEM-added “skins.” It currently sells with the Ice Cream version of Android and is supposed to be updated to the days-old Jelly Bean rendition of Android in mid-July.

The other patents Apple won on were its data tapping patent, its slide-to- unlock patent and its autocorrect patent, all like the Siri patent judged likely to prove valid.

The judge also found that, contrary to Samsung’s minimizing contentions, Siri is a “substantial driver of consumer demand” infringed by Google’s Quick Search Box technology. She’s less sure that the three other patents drive as much market share, FOSS Patents noted.

Apple will have to post a $94 million bond for the preliminary injunction to take effect. The ink on that check is probably already dry. Apple posted a $2.6 million bond to cover damages to Samsung in case it loses the day after it got a preliminary injunction against from the Android-based Galaxy Tab 10.1 tablet from Koh earlier in the week.

Reuters said Koh, who was pushed to order the injunctions by the Federal Court of Appeals, might rule Sunday on staying the injunction against the Galaxy Tab.

Apple is expected to go after the new Galaxy S III smartphone next.

The week before a Chicago court forbid Apple to chase an injunction against Motorola Mobility and its Android devices. However, as FOSS Patents deemed more important the judge said FRAND patents can’t be used for an injunction, a decision expected to weigh down the litigation strategies of Motorola, Samsung and Google with cement shoes.

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