Microsoft launches larger Surface Pro 3 to rival laptops
Microsoft has unveiled the Surface Pro 3 - a bigger-screened, faster Windows 8 tablet than its predecessor.
The new model features a 12in (30.5cm) touchscreen, 38% larger than before.
The firm boasted that at 9.1mm (0.36in) thick - without an optional clip-on keyboard - it becomes the "thinnest PC" to be powered by one of Intel's higher-end Core processors.
One analyst said he believed there was pent-up demand for such a device in the corporate world.
However, the platform has previously been outsold by rivals.
"The question that needs to be asked and answered is, 'Why hardware?'" said chief executive Satya Nadella at the launch event in New York.
"We clearly are not interested in building refrigerators or toasters. We are not building hardware for hardware's sake.
"We are not interested in competing with our OEMs [original equipment manufacturers].
"In fact, our goal is to create new categories and spark new demand for our entire ecosystem. That's what inspires us and motivates us with what we are doing in our devices and hardware."
According to research firm IDC, Apple, Samsung, Asus, Lenovo and Amazon have each outsold Microsoft with their tablets.
IDC says that the Surface platform as a whole accounted for just 1.5% of global tablet shipments - representing about 640,000 units - over the first three months of the year, down from a 1.8% share for the same period in 2013.
However, Microsoft is marketing the machine as being a "laptop replacement" - comparing it on stage to one of Apple's lightweight laptops rather than the iPad - and IDC research director John Delaney suggested it should be judged on those terms.
"To talk about it having a small percentage of the tablet market partly misses the point, because it's designed to appeal to PC buyers," he told the BBC.
"I think there's pent-up demand for something that does the job of a PC, that's light and thin, and that's cheaper than something like the MacBook Air. If the Surface Pro 3 also delivers good battery life, then that's a package that could resonate with a lot of buyers
"We're also seeing enterprises looking to replace at least some of their PCs with a portable touchscreen product that's compatible with their existing Microsoft applications and infrastructure software. That's another market to which the Surface Pro 3 could appeal."
The basic Surface Pro 3 will cost $799 (£475), compared with the low-end MacBook Air that costs $899.
Microsoft says the battery life is "up to nine hours", 10% more than the Surface Pro 2.RT no-show
Rumours that Microsoft would unveil a Surface Mini - powered by its Windows RT operating system - proved unfounded.
The RT side of the Surface business has previously struggled, with Microsoft having at one point to write-down the value of unsold stock by $900 (£534m) after it introduced an unplanned price cut.
Windows RT tablets run on ARM-based chips - giving them longer battery life but a smaller library of compatible software than machines using Intel or other x86 processors.
Adobe's image editing software Photoshop - which was shown off at the launch running on the Surface Pro - is one of RT's notable missing applications.
One industry watcher said he would not be surprised if Microsoft now decided to focus its Windows hardware efforts exclusively on its newly acquired Nokia handset business and the Surface Pro line-up.
"I think the RT experiment has now passed," said Ranjit Atwal, research director at Gartner, a tech consultancy.
"Bringing ARM and RT together really hasn't worked, so I wouldn't be surprised if it was phased out."