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A tactile keyboard with no mechanical parts
Earlier this month, Synaptics announced the acquisition of Pacinian, an Idaho-based interface company with a unique keyboard technology dubbed ThinTouch. Synaptics is being tight-lipped about some of the specifics regarding ThinTouch, but it did drop a few tasty morsels. Obviously, the keyboard is quite thin. We were quoted a thickness of less than 2.5 mm, compared to 3.5 to 6 mm for a keyboard with conventional scissor switches.

What sort of switch mechanism sits under the ThinTouch's keys? Synaptics isn't saying, but it did reveal that neither scissors nor mechanical parts are involved. The switch design is purportedly immune to wear and, according to Pacinian CEO Jim Schlosser, it uses no electricity. More about the ThinTouch design will be revealed at a later date, leaving plenty of time for speculation. No, it's not rubber domes.

Before the wheels start turning, know this: ThinTouch keys look and feel very similar to those of contemporary notebook keyboards. Synaptics had a couple of ThinTouch keys set up next to ones pulled from a MacBook Pro and an Acer ultrabook. The Apple and Acer keys required different amounts of force to actuate, and there were ThinTouch keys tuned to match each one. While the differences in actuation force were easy to perceive, the ThinTouch keys felt virtually indistinguishable from their Apple and Acer counterparts. The stroke lengths seemed similar, and the tactile feedback was comparable.

Then Synaptics told me to take a closer look at the actual key travel. Upon closer visual inspection, it was clear the Apple and Acer keys were traveling straight down, while the ThinTouch keys were moving down and toward the user. Even after seeing this sloped stroke path with my own eyes, it was difficult to feel the difference between the ThinTouch and conventional keys when punching them with my finger. Synaptics is mum on the effective stroke length for the ThinTouch keys, but I wouldn't be surprised if the diagonal travel was close to the vertical drop of a typical scissor switch mechanism.

There's more to the ThinTouch keyboard than its top-secret switches. Capacitive sensors also factor into the design. We didn't get to see this element first-hand, but it's part of Synaptics' bid for greater system integration. The capacitive sensors will be used to detect when one's hands are over the keyboard, at which point the touchpad will be disabled to prevent inadvertent contact from repositioning the cursor or causing unwanted clicks. Current touchpads feature a similar capability now, but they can react only to keys being pressed, not to hands resting on them.

In addition to smarter touchpad management, the capacitive sensors can be used for other functions. A concept video suggested that swiping one's fingers across the spacebar could be part of an auto-complete typing scheme. Auto-complete seems entirely unnecessary for a proper keyboard, unless you're a hopeless hunt-and-peck type, but the spacebar does seem ripe for thumb flicks or pinch gestures. I'd love to be able to move the cursor left and right by sliding my thumbs across the spacebar, for example. Switching between applications by waving one's hand left and right over the keyboard would be pretty cool, too.

Interestingly, the ThinTouch keyboard can also discern between different levels of force. Synaptics confirmed that this implementation uses different technology than the ForcePad but wouldn't go into further detail. More information will be revealed about the ThinTouch keyboard at a later date. It could be a while, because the ThinTouch isn't expected to infiltrate notebooks until the tail end of 2013.

Touchscreens, of course
As one might expect, touchscreens are rather important to Synaptics' business. ClearPads, as they're known, are available in a multitude of sizes. At the handheld end of the spectrum, current devices feature Series 2 or Series 3 ClearPads. The Series 2 models are designed for budget devices, and they consolidate their touch sensors in a separate component. Series 3 ClearPads are meant for premium devices and put the touch sensors directly into the display. This integration shaves off a millimeter of thickness and offers device makers an all-in-one solution that should be easier to implement than a separate touch sensor.

Capacitive touch sensors are split into separate transmitter and receiver layers. In the integrated ClearPads, they come in on-cell or in-cell flavors. The on-cell setups put both sensor layers on top of the color filter glass, which in turn sits atop the TFT glass. The in-cell approach lays the transmitters on top of the TFT and then situates the receivers on the color filter. Placing the transmitter layer under the color filter improves screen brightness by 10%, according to Synaptics. Having the color filter between the two sensor layers purportedly improves signal quality "by reducing the baseline capacitance of the sensor," as well.

Synaptics' Series 4 ClearPad is the new hotness. It's not in devices just yet, but customers are being shown demo units similar to the one pictured above. Both on- and in-cell setups are supported, this time with some consolidation on the silicon front. Instead of using separate touch and display drivers, the Series 4 combines both on the same chip. The resulting configuration is supposed to eliminate display noise. Synaptics says it also reduces the host processing load, cutting touchscreen latency by 70%.

To illustrate the Series 4 ClearPad's improved responsiveness, Synaptics fired up a version of its TouchExplorer Android app on the demo system. The app features a wide variety of touchscreen performance tests, and it can be downloaded directly from Synaptics' site.

In the demo we saw, TouchExplorer compared tracking data from standard and TDDI touch sensors. The standard sensor's response was represented by a yellow dot, while the TDDI sensor's input was tracked with the intersection of two lines. Check out our high-speed camera footage, which admittedly could have been framed better. I'm still figuring out how best to use our latest toy performance analysis tool.

Man, I love shooting at 240 frames per second. Notice how the yellow dot trails behind the finger, while the intersecting lines do a much better job of keeping up. The TDDI setup also detects the finger lifting off the display quicker than the standard config. Impressive.

Series 3 and 4 ClearPads top out at 5", so they're not big enough for tablets, notebooks, or hybrid cross-breeds. For larger devices, Synaptics has a family of Series 7 ClearPads that starts at 8.2" and goes all the way up to 17". Unfortunately, none of them are available with in-cell or TDDI configurations.