APPLE Inc Chief Executive Tim Cook defended the company's record of innovation under his stewardship, saying he expected it would release "several more game changers" and hinting that wearable computers could be among them.

"It's an area where it's ripe for exploration," Cook said on Tuesday at the All Things Digital conference, an annual gathering of technology and media executives in the California coastal resort town of Rancho Palos Verdes.

"It's ripe for us all getting excited about. I think there will be tons of companies playing in this."

His remarks come at a time when worries are rising that the company which created the smartphone and tablet markets is ceding ground to rivals such as Samsung Electronics Co and Google Inc, with a slowdown in earnings growth hitting its share price.

Cook stopped short of clarifying if Apple was working on wearable products amid speculation that it is developing a smartwatch, saying only that wearable computers had to be compelling.

He added that Google's Glass - a cross between a mobile computer and eyeglasses that can both record video and access the Internet - is likely to have only limited appeal.

"There's nothing that's going to convince a kid who has never worn glasses or a band or a watch to wear one, or at least I haven't seen it," he said in the near one-and-a-half-hour question and answer session.

"So I think there's lots of things to solve in this space."

Cook also said he has a "grand vision" for television that goes beyond an existing US$99 Apple TV streaming device, but did not go into details. The company has said for years that it has an interest in doing more in the TV arena.

Apple is not averse to doing a large acquisition if the acquired company could help Apple develop an important product, he said.