Apple Inc. said it's introducing a laptop with a super-high resolution "Retina" display, setting a new standard for screen sharpness.

The new MacBook Pro will have a 15-inch (38.1-centimetre) screen and four times the resolution of previous models, Apple executive Phil Schiller told developers at a conference in San Francisco on Monday.

Apple already uses "Retina" displays — with individual pixels too small to be distinguished by the naked eye — in its latest iPhones and iPads.

On the phones and tablets, the Retina display is a standard feature. On the MacBook, it's an expensive upgrade. The new MacBook will cost $2,199 and up, $400 more than the non-Retina MacBook with the same-sized screen.

The new MacBook is part of a general revamp of Apple's personal computer line announced Monday.

Apple also said the new version of its Mac operating system, Mountain Lion, will go on sale next month for $20. The update brings features from Apple's phone and tablet software, like the iMessage texting application, to the Mac.

Mountain Lion will also bring dictation to Macs. Users will be able to input text by talking to the computer, in any program. This is already a feature of Microsoft Corp.'s competing Windows software.

Apple CEO Tim Cook kicked off the company's annual conference for software developers on Monday, where he was expected to show off new iPhone software and updated Mac computers and provide more details on future releases of Mac software.

The announcement of new software for the iPhone, iPad and iPod Touch was confirmed by banners that appeared at the conference centre in San Francisco on Friday, reading "iOS 6." It's not much of a surprise. Apple has used its Worldwide Developers Conference as an opportunity to announce new iPhone software for the past few years.

Modest improvements expected

What's not known is what new features will come with iOS 6, or when it will be released to consumers. Usually, the new software becomes available for download around the time a new iPhone model appears. Apple-watchers expect the next version of the iPhone, the iPhone 5, to appear this fall, about a year after the launch of the 4S model.

In 2010, Apple demonstrated the new iPhone 4 at the WWDC, but analysts don't expect the company to show off a phone model this year.

With the launch of iOS 5 last year, Apple added many features already found in competing smartphone software. It also added the "Siri" virtual assistant feature, which interprets voice commands and talks back to the user.

This year, there are fewer "catch up" features to add, so Apple watchers expect more modest improvements. Some speculate that Facebook could become more tightly integrated, in much the same way that Apple baked Twitter functions into its software last year. That could make it easier to post Facebook status updates from within Apple's apps.

Apple already demonstrated most of the features of OS X 10.8 "Mountain Lion" in February and said it will go on sale late this summer. Developers are already able to download a version of the software. It narrows the gap between the PC and phone software packages, making Mac personal computers work more like iPhones.

Microsoft Corp., Apple's chief competitor in PC software, is on a parallel course. It's set to release Windows 8 later this year, bringing the look and user interface of Windows Phone to PCs.

Intel Corp. has just updated its processor line with faster, less power-hungry chips, and most of Apple's Mac lines haven't had a major update in a year.

Missing from Monday's presentation was any mention of Apple's ambition to get into making TVs. Analysts had speculated that Apple would at least update the software on the Apple TV, a small box that connects a TV set to iTunes for movie downloads, as a prelude to perhaps launching a fully integrated TV set.