Hands-on with Synaptics’ next-generation mobile input devices

A few weeks ago, Synaptics invited us down to Santa Clara, California, to check out its latest mobile computer input devices. How could we say no? Touchpads, touchscreens, and keyboards may not be as sexy as some components, but they’re the only tactile connections we have to the computing devices that are increasingly at our side or within arm’s reach. These physical inputs are fundamental parts of the user experience, and they often don’t get the attention they deserve.

As I sat at the airport gate editing another article, I couldn’t help but look down at my laptop and laugh. My trusty 11.6″ ultraportable is coming up on three years old, and she cost me just $550 new. An SSD upgrade has kept performance sufficiently snappy, and battery life is still great, but the inputs leave much to be desired. While the touchpad has decent gesture support, it’s comically small by today’s standards. The keyboard has gotten mushier with age, presumably because the underlying membrane has been beaten into submission by heavy-handed typing. Also, the TN display is painful to endure after being spoiled by the new wave of tablets and their IPS-fortified touchscreens.

The rise of touchscreens is the biggest trend in computer interfaces, especially with Windows 8’s October release fast approaching. Synaptics has all sorts of touchscreen products to cover a range of devices between smartphones and super-sized notebooks. More impressive are its innovative treatments of more traditional forms of mobile input: the touchpad and keyboard. Synaptics’ new ForcePad injects pressure sensitivity into a touchpad, while the ThinTouch completely rethinks keyboards. We got touchy feely to see what they’re like.

May the ForcePad be with you

Synaptics got its start in the touchpad business back in 1995 with the appropriately named TouchPad. The design combined a tracking area with separate buttons, an approach that dominated the notebook scene for more than a decade. The ClickPad came in 2010, doing away with discrete buttons in favor of a clickable tracking surface. It’s a higher-end solution than the TouchPad, which still finds its way into an awful lot of notebooks today.

For Windows 8, Synaptics told us Microsoft is recommending a tracking area no smaller than 105 x 65 mm (4.1″ x 2.6″ for the metric-impaired). There’s an appropriately named Modern ClickPad sized to match not only those dimensions, but also the new name for Win8’s Metro interface. That’s all well and good, but it’s not terribly exciting… at least when compared to the new ForcePad.

The ForcePad does away with tactile clicks in favor of pressure sensitivity. It can track as many as five fingers independently and register forces up to the equivalent of one kilogram (2.2 lbs) for each one. The ForcePad offers six bits of precision, allowing it to measure finger pressure in 15-gram increments.

Impressively, the ForcePad works its magic without moving parts. It barely even deforms under pressure. Synaptics told us the ForcePad deflects by only microns, which should be imperceptible to end users. My fingers definitely didn’t detect any sagging.

The lack of movement is potentially problematic, since folks are used to feeling a tactile click. However, Synaptics told us the usability testing it conducted internally and with Intel revealed users are just fine clicking without tactile feedback. The ubiquity of touchscreens probably has a lot to do with that.

Some people tap harder than others, so the ForcePad’s drivers will include a user-configurable click threshold. Synaptics was keen to point out that this threshold will be consistent across the entire tracking area, with none of the dead zones found on some clicky touchpads. The firm is also considering letting users enable an audible cue when clicks are registered.

As someone who has always enabled tap-to-click on conventional touchpads, I didn’t miss the lack of a physical click when using the ForcePad. Tapping to click felt natural, tracking was responsive, and the surface had very little friction, so it didn’t impede smooth finger movement. The first demo I was shown illustrated the force being applied by each finger using a series of colored columns that rose with increased pressure. The columns responded immediately even to subtle changes in pressure, and their sensitivity seemed consistent no matter where I pushed down. Next up was a flying game that pitched and banked based on pressure from different fingers. The controls worked nicely, but I crashed horribly—pilot error.

The final demo was sort of the opposite of the first. Instead of using rising columns, it depicted force input by deforming a model of none other than SpongeBob SquarePants. The effect was a little unnerving at first. Despite the fact that the ForcePad didn’t actually bend or warp, seeing the on-screen deformation made it feel like my fingers were pushing into the tracking area. Once I realized the ForcePad hadn’t turned to Jello, I quite enjoyed the sensation.

Of course, the ForcePad is good for more than just fancy demos. According to Synaptics, the chassis flex visible when some ultra-slim notebooks are held at one corner can generate phantom clicks on some clicky touchpads. The ForcePad can detect this flex and compensate accordingly. Synaptics also offers an automatic calibration system that allows notebook makers to offer a consistent ForcePad feel across different chassis designs.

Expect to see the ForcePad primarily in ultrabooks. It won’t replace the ClickPad but will cost notebook makers a little more. The ForcePad should give manufacturers more wiggle room in their designs, though. At just 3 mm thick, it’s notably thinner than the ClickPad, which measures a pudgier 5.5 mm. That’s probably part of the reason Intel has apparently selected the ForcePad for its next-generation ultrabook reference design. Other notebooks featuring the ForcePad are expected later next year.

Until then, your best shot at getting some hands-on time with the ForcePad is the User Interface Software and Technology conference, otherwise known as UIST. The conference is organized by the Association for Computing Machinery, and it features a student contest that asks teams to develop novel ways to use unique interface technology. Last year’s UIST contest was centered on a touch-enabled Microsoft mouse, and this year’s competition involves the ForcePad.

Synaptics developed an external ForcePad module for the contest. With the help of a hardware partner, it would like to offer something similar to the general public. The firm sees potential in gaming, and I suspect developers will find other interesting applications for the ForcePad’s pressure sensitivity.

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.

Putting it all together

Synaptics makes no secret of its intent to own all of a notebook’s physical inputs: the touchpad, the keyboard, and the touchscreen. The firm already has a substantial slice of the touchpad market, and it’s hailing the ForcePad as the most significant innovation in that segment since 1995. From a purely technical perspective, that doesn’t seem like too much of a stretch. The pressure sensitivity in the ForcePad I tried felt very slick, and the design is thinner than conventional alternatives. Whether the ability to detect the firmness of one’s touch proves more valuable than, say, gesture recognition very much depends on what developers do with the capability. There’s certainly plenty of potential for cool applications.

When ForcePads finally become available next year, they’ll at least have some extra mojo in Windows 8. After coming up with 20 force-enabled gestures in its usability labs, Synaptics settled on five for the final driver. Among them, force-enhanced scrolling and zooming gestures whose speed is determined by finger pressure. There’s a continuation function that allows those gestures to be extended past the edge of the tracking area simply by pressing harder, as well.

I’m eager to see what developers do with the technology and whether anyone can come up with a compelling gaming application. Too bad “materials requirements” will keep the ForcePad’s pressure sensitivity out of touchscreens.

The ForcePad might have been the star of the show, but as a writer who bangs out thousands of words in the average day, the ThinTouch keyboard was nearly as impressive. I’m amazed a switch mechanism less than 2.5 mm thick felt so good. The ThinTouch is purportedly easier to backlight than existing switch technology, too. No wonder Synaptics is keeping the particulars of the design hush-hush for now.

If you haven’t noticed, thinness is sort of a theme with Synaptics’ next-gen input tech. No, the company isn’t trying to squeeze itself into a pair of hipster skinny jeans. As it repeatedly noted, thinner keyboards and touchpads afford notebook—and particularly ultrabook—makers greater flexibility. They can use the millimeters saved to make the entire chassis thinner or put the extra space to better use, either by adding battery capacity to extend run times or by employing beefier cooling to accommodate faster processors. When you think about the footprint of the keyboard and touchpad on modern notebooks, even a couple millimeters translates to a not-insignificant portion of the total system volume.

Meanwhile, the ClearPad Series 4’s focus on latency reduction is encouraging to see. Cutting touchscreen latency is an important part of smoothing out the user experience. I just wish the new driver silicon was available with touchscreen sizes large enough for Windows 8 tablet-notebook hybrids.

Although Synaptics’ next-gen input technologies have definite appeal, it may not be easy to determine which future products are actually using them. Synaptics was candid about the fact that it doesn’t have the money to fund an Intel Inside-style logo program. Manufacturers rarely advertise the origins of the touchpads, keyboards, or touchscreens used in their devices. Some even use multiplier suppliers, making it especially difficult for consumers to know what they’re getting before opening the box.

The quality of the touchpad, keyboard, and touchscreen has become an increasingly important differentiating factor for mobile devices, especially notebooks. After sampling Synaptics’ next-gen units, I can’t help but wish device makers would state which input hardware they’re using as clearly as they describe other system components, such as processors, graphics chips, and hard drives. Based on what I saw, the ForcePad, ThinTouch keyboard, and Series 4 ClearPad are all worth seeking out. At least the ForcePad’s unique pressure sensitivity should be easy to spot.

Comments closed
    • cynan
    • 7 years ago

    Great article. It’s reassuring to know that groundbreaking R&D are still being done on the more generic input devices.

    I would think, off the bat, that one of the more useful features of a ForcePad would be to be able to set a minimum force for an “unlocking” press to toggle the touch pad on and off on a smaller laptop: I find it annoying sometimes when I’m typing on a cramped surface, perhaps in a sub optimal ergonomics (like when it’s on my lap), when I occasionally brush the touch pad with my palm and the next thing I know I’m over writing sentences in the previous paragraph or worse… It would be great to be able to toggle the touch pad on and off by simply pressing a bit harder on it, instead of having to hunt around for the function key on the laptop that does this.

    [quote<]The ForcePad can detect this flex and compensate accordingly. Synaptics also offers an automatic calibration system that allows notebook makers to offer a consistent ForcePad feel across different chassis designs. Expect to see the ForcePad primarily in ultrabooks. It won't replace the ClickPad but will cost notebook makers a little more. [/quote<] Unfortunately, the makers of cheaper notebooks that are most likely to suffer from flex issues are not not likely to pay the premium for it though..

    • ronch
    • 7 years ago

    Not sure I’m really impressed. I guess I have to try it out for myself to believe it.

    It’s kinda hard to imagine what sort of input method people will be using decades down the road. We have motion sensors now such as those featured by the Kinect which is pretty much leading-edge. Perhaps in the future the display will track your eye movement, and when you blink, it’s equivalent to the double-click of the mouse today. But seeing as most folks blink every few seconds, does it mean they have to look away from the monitor before blinking to avoid unintentionally launching programs? Or perhaps you have to stare at an icon long enough to launch the program behind it?

    • willmore
    • 7 years ago

    Second to last paragraph:
    “Some even use multiplier suppliers, …”

    Loved the article. Really need stuff. I downloaded their app onto my Nexus 7 tablet. Maybe I have big hands, but I could barely fit 10 fingers on the screen.

    • Left_SHifted
    • 7 years ago

    Awesome article guys.

    Once again TR displays its propensity to touch(and feel) details where other sites just won’t go 😛

    • RtFusion
    • 7 years ago

    This is great news. The Acer Aspire 5740-5517 that I have now has a multi-gesture Synaptics touchpad and I love it (despite me hating the laptop itself). I can do a two-finger scroll up and down and two-finger swipe left or right to move between pages or in my case, pages in online manga readers. Super handy.

    I can also rotate images as well as expand/shrink text/docs (in Word 2010 at least) and images with the touchpad as well, although I don’t use those features that often.

    After reading this fantastic article (thanks!) I can’t wait for next generation notebooks to have Synaptic tech in them. I really hope they the OEMs would actually slap a Synaptics sticker on them to notify customers what they are really getting with their input technology.

    If in the future TR reviews more and more mobile products, particularly notebooks, I agree with alloyD that information about a particular device’s input technology should be investigated upon to show what you will get if you get that particular device.


    According to an article on SemiAccurate, the ThinTouch keys uses ramps of sort according to a diagram that the article has.
    [url<]http://semiaccurate.com/2012/08/20/synaptics-brings-force-to-touch/[/url<] Very interesting I say.

    • MethylONE
    • 7 years ago

    I think the swiping space bar seems like a great addition. I can totally see using that.

    • eitje
    • 7 years ago

    Geoff, I appear to have missed your update on what is happening with nubbin mice – the best kind of mobile interface.


      • Dposcorp
      • 7 years ago

      nubbin mice? Last I heard, they lost that nubbin feelin. 🙂

    • flip-mode
    • 7 years ago

    Very cool article.

    • alloyD
    • 7 years ago

    Do you think that this type of information might be incorporated into future TR reviews? It would be great if in mobile device reviews, TR included information on what interface equipment was installed (assuming it’s not proprietary hardware comme apple). That may be easier said than done, but I know I would love to know that before I decide to buy something.

    • Dposcorp
    • 7 years ago

    Very cool little article; off the beaten path and not the usual stuff.
    Its gonna be nice to see touchpads that can do more on future devices.

    • Bensam123
    • 7 years ago

    You know, it’s interesting hearing about Synaptic. It’s one of those companies that have been a part of laptops forever, but given very little recognition. I have to wonder how much of the ‘forcepad’ is about force though. From what I’ve seen, touchpads operate based on heat. They’re essentially thermal pads, not touch pads… touch implying force. That’s why it’s possible to move the cursor without ever touching the pad.

    It makes me wonder if the forcepad is just simply a normal touchpad with tweaked drivers that detect how much of your finger is actually touching the pad. The more force you apply to a touchpad, the more your finger spreads out over the pad. Applying force also applies more heat, so while your finger would spread out over the pad, the force from it would also generate more heat in the center. Although it’s not a completely ideal solution (say someone with fingers that don’t deform when force is applied to them), it would be possible to mimic this behavior in current touchpads.

    It’ll be cool to see where that keyboard goes though, that’d be a neat upgrade for a laptop.

    First page, “are using to”

    …used to…

      • chuckula
      • 7 years ago

      [quote<]From what I've seen, touchpads operate based on heat. They're essentially thermal pads, not touch pads[/quote<] ???? --> Did you intentionally put in something ridiculous like that to troll us or something? Go read some Wikipedia: [url<]http://en.wikipedia.org/wiki/Touchpad[/url<]

        • Bensam123
        • 7 years ago

        Perhaps I’m mistaken, but from what I’ve read some touchpads ARE heat sensitive. The Wiki entry you pasted lists them as being capacitive sensitive… Which still is not pressure related.

        No, I wasn’t trying to troll anyone.

      • bhassel
      • 7 years ago

      As chuckula said, touchpads have nothing to do with heat. They are based on capacitance — basically, they detect your finger interfering with an electrical field above the touchpad.

    • MadManOriginal
    • 7 years ago

    tl;dr question: So are trackpads going to stop sucking soon?

      • adisor19
      • 7 years ago

      FTFY So are PC trackpads going to stop sucking soon ?


        • MadManOriginal
        • 7 years ago

        Yes that’s right, the ones that actually matter for 90%+ of the market.

        • superjawes
        • 7 years ago

        I’m a little ashamed, but I had to +1 you for that…

        • Hattig
        • 7 years ago

        Have to agree there, have been using great trackpads on Macs for years and years and they’ve been great, yet many PC laptops still come with really crap touchpads – too small, stupid buttons, rubbish feel, annoying features, indented into case with large ridge, poor touch registration…

          • pedro
          • 7 years ago

          And let’s not forget the infuriating phantom clicks.

          • Shambles
          • 7 years ago

          Well I certainly wouldn’t expect the touchpad in a $500 PC laptop to be as nice as the touchpad in a $2000 mac laptop.

      • derFunkenstein
      • 7 years ago

      No, they’ll still be too small and placed poorly, and the drivers will still mis-interpret your desires. All the quality trackpads in the world can’t account for human stupidity.

        • GTVic
        • 7 years ago

        Yeah, bring back mice with the little balls inside. Those were the best.

        edit: sorry that was in response to MMO.

      • nciaootu
      • 7 years ago

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