At a May 30 technology conference sponsored by the Wall Street Journal, technology companies from Microsoft Corp. to Silicon Valley start-ups introduced computers with fundamentally new forms.

Microsoft unveiled the fruits of six years of research pushed by Chairman Bill Gates–a computer designed like a table with a touch screen. The system, called Surface and aimed initially for use in hotels and casinos, includes features that allow users to buy tickets to events, wirelessly retrieve and display photos, and play games. It goes on sale later this year.

At the same event, an Oakland, Calif., start-up called Livescribe Inc. introduced a pen-shaped computer that can make audio recordings and link them to written notes.

The new products, shown at the “D: All Things Digital” conference in Carlsbad, Calif., are just a few examples of the quest by large and small technology companies to change the shape of computers. After an initial innovation boom, most PC makers for years have churned out cookie-cutter desktops and laptops. Though they have become less expensive and smaller on the whole, other major changes have been rare.

But the picture is changing, inspired by innovations such as Apple Inc.’s iPod and other stylish products. Besides working on aesthetics, companies are experimenting with new uses for computers and new ways for people to interact with them–including wider use of voice input, styluses, and touch screens.

For Gates, Surface is part of a quest to expand the definition of the PC. “I’ve been saying the last few years that the thing people are underestimating the most is how ‘natural interface’ will change computing,” he said. For many years, he has promoted speech input, stylus-based computing, and–with Surface–visual recognition.

So far, those variations on the keyboard have been slow to catch on. Microsoft five years ago introduced the Tablet PC, which features a large screen that can be controlled with a stylus rather than a keyboard. While some schools use them as portable computers, they still haven’t caught on widely.

Surface, a table with a square, 30-inch acrylic top, combines five cameras with Wi-Fi and Bluetooth wireless connectivity to detect objects and movement. It uses a version of the Windows Vista operating system with additional Microsoft software. As users move their hands on the tabletop, cameras translate the motions into commands. For instance, users can select a color by touching a virtual palette and then “paint” images on the screen with their fingers or a brush.

Wireless technology transfers stored photos from a digital camera or cell phone placed on the table to the Surface screen. A motion of the hand on the touch screen can make the images larger or smaller. They can be moved to another camera or a hard drive by sliding the images across the table, much as one would slide a picture across a regular table.

In a recent demonstration, Microsoft executives showed how the object-recognition feature could work for Harrah’s Entertainment Inc. Placing a loyalty card for the casino operator on the table summons a map of Caesar’s Palace. Tapping on the casino’s different venues reveals show times, menus, descriptions of nightclubs, and other information, allowing a guest to book tickets, make reservations, or even gamble.

Microsoft executives see new ways for establishments to interact with customers. Placing a wine glass with a tag similar to a bar code on the table, for example, could call up details about the wine and its vineyard.

Starting at $5,000 to $10,000, and needing considerable customization, Surface

isn’t suited for schools now. But Microsoft expects high-profile hotel and restaurant operators to bring exposure.

“Literally millions of people will see it through the different partners we have,” Gates says. “But the big numbers come when our hardware partners pick it up and build devices for the office and home environments.” He expects that in three to five years, greater sales volumes will help drive down the cost of the Surface technology, enabling the company to “get to price points that are under a thousand dollars for broad usage,” he says.

Livescribe’s pen-shaped computer, meanwhile, is initially aimed at college students. It builds on technology that was invented by Sweden’s Anoto Group AB and used in the popular Fly Pentop Computer from LeapFrog Enterprises Inc.

Livescribe’s founder and chief executive, Jim Marggraff, previously worked at LeapFrog and for Anoto. The approach relies on special paper with tiny dots that help a sensor in the pen distinguish locations on a page and assign them special functions. With the Fly, for example, users can draw a calculator and then touch the numbers to trigger a calculation heard through a speaker or earphones.

Livescribe’s “Smartpen” adds a microphone and a small display on the side of the pen. A user can tap on a section of written notes, for example, and call up a recording in the pen of what an instructor was saying when those words were written.

Marggraff, who expects to deliver the device in October for less than $200, plans to create a community of programmers to write exchange applications for the Smartpen.

“I believe this will affect the way people think,” he says.