Lenovo is updating the design of its ThinkPad laptops to keep them up-to-date in a market where computers are getting thinner and lighter at a fast rate.

The ThinkPad's external appearance isn't changing a great deal, but it is getting considerably thinner and lighter. The changes are exemplified in the new ThinkPad T431s, which will go on sale next month.

The T431s weighs 1.36kg, or 24 percent less than the existing T430s, and it is 20.6 millimeters thick, or 21 percent thinner. It does away with the buttons around the touchpad and has a slightly thinner bezel around the display, and it comes in a lighter shade of black.

With the buttons gone, users now click on areas of a slightly enlarged touchpad to make selections and execute commands. The new ThinkPad still has the little red tracker button in the keyboard, as well as the other main features in existing ThinkPads.

"We don't change things all that often. We put in a lot of thought into all we did," said Alysia Baker, worldwide product marketing manager at Lenovo.

The bigger touchpad makes it more useful, according to Baker. That could be especially true with the release of Windows 8, which understands more types of gestures.

Focussing on the future and current users

The ThinkPad is keeping up with the times by getting thinner and lighter, but the inclusion of the red trackpoint button shows how Lenovo must cater to corporate ThinkPad users who may be resistant to change, says David Daoud, a research director at IDC.

Having to keep existing features makes life a bit harder for Lenovo. The trackpoint allows for precise navigation, which may be helpful for workers such as graphic designers, Daoud said.

"Many of these people have built a comfort zone and therefore a loyalty for this type of product," Daoud said.

Camellia Phillips, an avid ThinkPad user, has grown accustomed to using the buttons around the touchpad in conjunction with the red trackpoint button. She prefers the buttons to be visible rather than integrated with the touchpad.

"That's annoying. Why are they changing something that works so well?" Phillips said. She owns three ThinkPads and, like other ThinkPad users, appreciates the consistency and reliability of their design.

A '13-inch' laptop with a 14-inch screen

Lenovo also reduced the bezel area around the display in the T431s and put a 14-inch screen in what would otherwise be a frame for a 13-inch screen. The hinge is also more flexible and can tilt the panel through 180 degrees.

The changes will ultimately make their way to other T-series laptops, Baker said.

The ThinkPad went through a minor redesign with the ThinkPad X1 Carbon laptop, which was introduced late last year and included a new carbon fiber frame. That frame has been included in the T431s, though Baker was not sure whether it would be carried over to all other ThinkPads.

The T431s comes with an Intel Core i5 or i7 processor based on the Ivy Bridge microarchitecture. OS options include Windows 7 or Windows 8. The laptop can accommodate up to 12GB of DRAM and comes with a hard drive as big as 1TB or up to 256GB of solid-state storage. It also has a MiniDisplayPort, USB 3.0 and Ethernet ports.

The laptop provides nine hours of battery life, according to Lenovo's benchmarks. It has a webcam, and the display shows images at a resolution of 1600 x 900 pixels.