CUPERTINO, Calif. » A perfect iPhone? There’s no app for that.

Apple Inc. will give free protective cases to buyers of its latest iPhone to prevent reception problems that occur when people cover a certain spot on the phone with a bare hand.

CEO Steve Jobs apologized yesterday to people who are less than satisfied with the iPhone 4, even as he denied it has an antenna problem that needs fixing.

"We’re not perfect," Jobs said at a news conference. "Phones aren’t perfect."

The more than 3 million people who have already bought an iPhone 4 can go to Apple’s website starting late next week and sign up for a free case, he said. Apple can’t make enough of its $29 "Bumper" cases for everyone, so the company will let people chose from several case styles.

New buyers through Sept. 30 will also be eligible. Apple will send refunds to people who already bought a Bumper.

Jobs, expressing irritation with the critical coverage of the phone’s reception problems, echoed an earlier statement from Apple that no cell phone gets perfect reception. He played a video showing competing phones, including a BlackBerry from Research in Motion Ltd., losing signal strength when held in certain ways.

Phones usually have an antenna inside the body. In designing the iPhone 4, Apple took a gamble on a new design, using parts of the phone’s outer casing as the antenna. That saved space inside the tightly packed body of the phone, but meant that covering a spot on the lower left edge blocked the wireless signal.

Consumer Reports magazine said covering the spot with a case or even a piece of duct tape alleviates the problem. It refused to give the iPhone 4 its "recommended" stamp of approval for that reason, and on Monday it urged Apple to compensate buyers and fix the problem.

Jobs, a cancer survivor, also addressed a question about his health yesterday.

"I’m doing fine. I was even better earlier in the week (when) I was having a vacation in Hawaii, but I decided this was important enough to come back for," he said. "I’m doing great.