Following on from our second article, "Developers on the ThinkPad Tablet 2 - Mechanical Engineering/Industrial Design", we once again speak directly with the developers.
In this third session, we discuss focusing on hardware development for touch panels and digitizer pens that are directly related to the user experience. Here are the interviews with two veteran engineers, one who has experience formulating engineering standards for mobile phones from the users' standpoint, and the other who started his career designing LCD circuits and is currently responsible for tablet LCDs.
- The Tablet 2 got high marks for its beautiful screen and great touch performance.
Kawakita: It's really great news for us. We have been researching touch-technology for a long time now and we're utilizing the fruit of our labor.
Actually, a clear technique that enables the measurement of the comprehensive performance of things like smoothness of touch and response speed did not exist. So we had to begin with the development of that technique itself. But when we completed the technique to some extent, we had become confident that it would work out fine.
However, you can't see things one-sidedly. You have to prove the result by measuring performances with the technique. So we asked for the cooperation of a major information technology institute and brought to California a Tablet 2 to evaluate it through a comparison with competitors' machines. The result was the same as we obtained. So we decided "Let's go with this!"
The resulting Tablet 2 turned out to be excellent. Even the most well-known tablets by other companies are no match.
Comparison graph of touch performance
Tsuchihashi: As a genuine ThinkPad tablet, the Tablet 2 came out with the best combination of a IPS LCD panel and direct bonding for the first time on the market.
Moreover, the Tablet 2 adopted a manufacturing method called direct bonding, in which LCDs and glass are directly attached using a resin. The screen is beautiful, reduces reflection and the disparity in the visual display when using a pen, as well as input sound.
- At this moment, the quality of touch panels are top class. What about cost?
Tsuchihashi: The technology is costly but we have reduced them to the minimum. The level of perfection against the price of the product has reached a very satisfactory level. This trend will most likely become the mainstream in the industry in the future, and I believe this is something we rightfully challenged as a leading company.
There is another aspect to the good quality. This time we are using 24-bit true color RGB LCDs. If you compare this with 18-bit RGB LCDs, the reproducibility and gradation of colors is more realistic. I think that's another reason for the high approval of the Tablet 2.
Kawakita: In order to achieve superior touch performance, a comprehensive development of not only the quality of the hardware but also the quality of firmware, as well as joint work with Intel and Microsoft, is necessary.
So we did not carry out any development of the technique through hardware. In other words, we are using an index only indicating human's sensation like "Do you feel good when using it?" in numerical terms. Our methods might be close to "sense engineering".
I think only Yamato Labs could make this type of development considering the user experience happen at a high level.
- The digitizer pen is another feature of the Tablet 2. You said they're easy to use. How exactly?
Tsuchihashi: In the manufacturing method called air bonding used in most products, which creates a gap between the LCD and the glass, there is a bit of a disparity when using a pen. This disparity is the difference between the actual location of the pen on the screen and the position you see.
However in the case of direct bonding, the LCD display directly under the glass, and this reduces the disparity and you can write as if writing on paper, and feels very comfortable. Sound plays a role, too. Because there is no gap where sound echoes, the tapping sound is smaller when the pen touches the glass.
We're now using a compact, active digitizer pen with no built-in batteries. The pen has a coil and the digitizer sheet located under the LCD picks up the coil, detecting the pen with a high degree of accuracy. The pen is more than 10 times as accurate when compared to ordinary elctrostatic pens. You can even write small letters. Because it feels as if you're writing with a ballpoint pen, it's really feels good.
With both portability and usability, we've created a digitizer pen that fits the tablet right on the money.
- I get it. "Feeling good", which is directly linked to the user experience is a great concept. Do you have any secret developments story or struggles?
Kawakita: All we have had are struggles (LOL).
Touch performance is one of the requirements of logo authentication in Windows 8. We had a difficult time because our test machines were not stable. We implemented a beta test but it was like tightrope walking. The reason was clear, so we were able to improve it after several negotiations and eventually got through it somehow.
But just after we relaxed, the most critical moment came.
We conducted a touch performance test while the product was communicating through LAN. But we couldn't pass the test when it is communicating through wireless LAN. The test was run in Taiwan in a place like Tokyo's Electric Town (grin), so we hurried to a local electronics store and purchased 50 meters of LAN cables. The distance between the LAN slot and the test field of the facility was so far... We asked an official at the facility and wired the LAN cable in the facility. At last, one day, we finally passed the test at 10 o'clock in the evening...
But, from this kind of experience we were able to get technical know-how, so I want to share it inside the Yamato Labs.
Tsuchihashi: We jumped through hoops to figure out why the eCompass wasn't moving properly
The eCompass is an electronic compass that can detect the earth's magnetic field just like a directional compass. More precise than GPS, you can know exactly which direction you're facing, and the display matches the map to your direction of movement.
On the Tablet 2, the digitizer sheet to detect the digitizer pen was attached to the back of the LCD, and it didn't go well with the eCompass. So, we repeated our review of the proposal to combine the capabilities of both the pen and the eCompass. In the review were things such as changing the tuning of the eCompass itself and the location of digitizer sheet and the eCompass . After negotiating with the manufacturer, and as a result of the effort of the young engineer in charge of the eCompass, we fixed it in the final stage of development... It's was really a close call.
- I'm sweating over here just from listening… You did great work! Do you have anything you want to add about what you want to do in the future?
Kawakita: We have all of the know-how, so I want to establish a steadfast development approach and quickly formulate a reference design
However, there are many things that must be looked into. For example, touch performance is not just the quality of the smoothness of touch and its response, but the combination of various things. Weight balance and the fineness of the screen are also involved. The number of products with touch panels is increasing, therefore I would like to consider these things more in the future.
Touch technology is rapidly evolving. Beyond the research of the latest products, we want to develop products that always consider the user experience.
Koji Kawakita holding the Tablet 2
Tsuchihashi: I want to challenge more the thickness of touch panel units. The problem is that even with only four parts (reinforced glass, direct bonding, LCD, digitizer sheet), miniaturization of these depends on the evolution of these technologies.
And in the next models, I'd like to bring back the erasing function on digitizer pens. This is because the X Series convertible tablet had an eraser. Also, the goal is to create something that feels more and more like a real pen, with a non-slip rubber finish, high digitizer precision and appropriate perception of writing pressure.
This is something from the "Yamato Spirit Meeting" with customers in Japan, but a "tablet that can be firmly grasped when using the keyboard" must be developed. But… this is not my responsibility, so to everyone in the project team, have fun!
Moriyuki Tsuchihashi holding the Tablet 2