SAN FRANCISCO (MarketWatch) -- Amazon.com plans to keep its Kindle e-reader device focused on long-form reading to compete against new multi-purpose tablet devices such as the iPad, the CEO of the e-commerce giant said on Tuesday.

At an annual meeting of Amazon AMZN, +0.12% shareholders, CEO Jeff Bezos said the company has sold "millions" of its e-reader product known as the Kindle. The company has never given specific sales data for the device, which first went on sale two-and-a-half years ago and has since shaken up the market for electronic books.

Amazon.com CEO Jeff Bezos with the company's Kindle e-reader. Reuters

But the Kindle has since come under heavy competition, not only from other companies such as Sony Corp. that are making E-Ink-based reader devices, but from powerhouse Apple Inc. AAPL, +1.50% , which launched its iPad tablet in early April and has since sold more than 1 million units of the device.

Asked by a shareholder at the meeting about the iPad, Bezos said the Kindle will compete by remaining focused on readers.

"The Kindle will compete with these LCD devices like the iPad by being a very focused product," Bezos said at the meeting, which was webcast. "Serious readers are going to want a purpose-built device, because it's an important activity for them."

He compared using a camera built into a cell phone compared to having a stand-alone camera, noting that a strong market remains for cameras despite their wide availability on other types of devices.

"If an activity is important, you get dedicated devices," he said.

Bezos noted that disadvantages remain with LCD products like the iPad for long-form reading, including eye strain and battery life. LCD products also don't typically work well in bright sunlight, he said.

But LCD screens offer one key advantage over E-Ink products such as the Kindle -- color.

One shareholder asked Bezos when the Kindle might be available with a color screen. He said the ability to offer "high-quality color" on reflective displays "is still some ways out."