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I’m developing a touch based gaming unit and I need it to take a beating. I’m told that there is a difference in my options for coverglass on PCAP – that it’s easiest to have thick glass instead of polycarb – is this true and why is that?

Gamer Dude,

Touch Guy knows about beating on gaming machines, and not only the one he beat after it stole his money.. At one time, during the heyday of S-cap in gaming machines, TI was the largest supplier to the Las Vegas repair market; we have photos of bullet holes, deep cuts from keys and diamond rings, and a brick being tossed at an outdoor gaming machine in Europe. So we can help you make your machine super-tough.

P-cap has yet to become the dominate force in gaming machines, mostly because the market is not expanding as fast as it once did, and many casinos are holding on to their machines longer than they did in the past. However, compared to the existing S-cap and IR systems, P-cap offers a lower cost, more reliable solution. But you knew that, and are asking about the touch surface. In Touch Guy’s experience, based upon outside, unsupervised machines, (ATM’s comes to mind), you will find a tempered glass first surface to be your best choice. Tempered glass, is a very low cost material and can be laminated with a standard p-cap sensor all the way up to the level of being bullet proof (literally). Automobile windows are laminated tempered glass. Should your machine need a curved touch screen, this would be the way to go as well. Bring on the pounding.

Chemically hardened plastics have been remarkably improved in the last two years, some claiming scratch resistance equal to that of glass….we have tested and can confirm that is TouchGuy_Basicaccurate. Touch uses these magic plastics in products it is shipping now and our customers are pleased with the performance. However, we need to warn you that they are extremely expensive. As a minor consideration, the image from the display is not quite as good, and the touch sensitivity may be a little bit less good than with glass. If you are one of the lucky ones that does not have a weight problem, I mean your machine does not have a weight budget, lower cost tempered glass, even chemically strengthened glass, is a better choice than any of the exotic plastics.

If you have not read the white paper on hardened glass you might take a look at http://touchinternational.com/literature/Glass-Substrates-Whitepaper.html

However, if you really want to use those expensive plastics, you might as well consider TI’s soon to be release PCAP Plus, which will add pressure sensing and immunity to the cuba libre dumped on your new machine while preserving the no-wear, great image, and mutl-touch features of the p-cap solution.

Until Next Time,
Touch Guy

We are designing for an application where the customer needs to touch more than one touch screen simultaneously. We want to use projected capacitive for its scratch resistance but are not sure how to manage the interference problem when two screens are touched at the same time. Do you have any suggestions on how to solve this problem?

Hey Keith C.,

Two-timing touch on multiple displays is an old surface capacitive problem with a complicated solution. I am assuming you are using the same computer running a multi-display solution under windows. By now you know that multi-touch electronics send information to the multi-touch driver which converts it to the equivalent of multiple mice being connected to your computer. To create the actual touch, the driver takes the X-Y coordinate touch point to move touch guythe mouse pointer in the video RAM to the touch point and issues a click. So far, so good.

Now you are going to connect multiple displays, which are supported by the Windows system. Again, so far, so good. But here is the rub. The touch electronics have a USB name that tells the Windows driver that there is a multi-touch device out there. If you plug in two USB touch screens, the Windows driver will not know which touch screen is associated with which display, and, further, would be totally annoyed at you for trying to trick it with two devices with the same name.

For this application, Touch International can change the name of each of the two electronic controllers (so you can know which is which), but this would not make the Windows driver any more capable. So, now you have to call in the big-guns and get them to sell you a multi-touch-multi-display driver. This can and has been done, but get out your wallet. Touch can give you suggestions for software companies that can do this.

Till next time, Touch Guy

When evaluating a touch screen for a hardened handheld product (the system must survive a 3-5 foot drop onto cement, and cleaning with alcohol and water), how does resistive multi-touch compare with projected capacitive, particularly for gloved hand (1-2 layers of latex or nitrile), multi-touch and gesturing GUI’s?

Scott, you get one question and one bonus question all rolled into one Touch Guy answer.

With more than 50,000 iPhone touch screens being replaced per month with cracks, broken touch screens have become a big business so we kinda like the breakage. But I guess a broken screen keeping you from your Facebook page is a lot different than not being able to reprogram a defibrillator! Before Touch Guy cuts to the answer, he TouchGuy_Basicwants to emphasize that good product design means the whole assembly – touch screen, LCD, and enclosure – need to be skillfully integrated to meet the breakage requirement. And that is a good segue into reminding you that Touch International provides bonding of the touch panel to the LCD with a shock absorbing optical gel that substantially reduces breakage in mission critical devices.

The simple answer to what technology is most breakage resistant is…..it’s a tie. This is because both products can be made using all plastic components. New top level hardcoats resist scratches  and claim to have a hardness of 6H (traditional plastic touch panels have a hardness of 3H or 4H), and they have always been resistant to most harsh chemicals…alcohol is wimpy
compared to the super-hot acids and lye that these things see in processing.

All things being equal, you would pick the all plastic projected capacitive over multi-touch resistive (MARS) for optical clarity and longevity; however, while projected capacitive will perform nicely with two layers of nitrile gloves, if a doctor, soldier, or pilot wants to occasionally want to use a scalpel, thick work gloves or a pencil, you better go with MARS because it will work with absolutely anything.

As a parting shot, Touch Guy wants to say that this is a very general answer, and knowing the application and its requirements might result in a solution that uses a specialty glass like safety or bullet proof glass that might be better than an all plastic solution.

Until next time, Touch Guy