Tag Archive for: LCD

My company is developing a sleek new GPS and we’re looking for the right touch solution. We’ve looked at projected capacitive touch screens, but feel the cost will push our product’s price point up too much. What do you suggest?

Hey Touch Guy,

My company is developing a sleek new GPS and we’re looking for the right touch solution. We’ve looked at projected capacitive touch screens, but feel the cost will push our product’s price point up too much. Our touch screen requirements are:

  1. 4.3″ Screen
  2. High Optics
  3. Scratch Resistant
  4. Anti-Glare Screen
  5. Lower Cost Display

Mark Hood, Red Lake Falles, Minnesota

Dear Mark,

So I hear it is so frigid up there right now that cold fusion once again might be proven. The marketing lady wants a fast answer so she can go home for the holidays, so the answer is, buy projected capacitive!

The biggest reason people think projected capacitive is more expensive than TouchGuy_Basicresistive is that you are buying a different product. Resistive touch panels and projected capacitive touch panels are made of the same materials, but the processing is a little different. Resistive touch panels are usually mounted between a bezel and an LCD, and boom, you’re done. However, Touch Guy finds that nobody wants a projected capacitive panel that way. Instead they want the touch panel to BE the bezel and front of the product; they suddenly want zero borders around the edges, the cover lens should have pretty colors, rounded corners, button holes and be almost unbreakable. Oh, and add a high-tech sunlight readable coating, and, for good measure, throw in an anti-fingerprint finish. Guess what….it costs more!!!

The electronic controllers for projected capacitive panels are more expensive than for resistive touch panels, but competition has dramatically dropped the unit price this year. A controller chip for a resistive panel might be less than $1 (or free, if included in the ASIC).

The bottom line is you can either adhere to your requirements and buy projected capacitive or you can lower your standards and buy resistive, cause there ain’t no way you are going to get good optics and scratch resistance with that one. So wedge a projected capacitive sensor into your GPS bezel, put the control electronics into the ASIC, and you will pay about the same price as resistive, and you’ll get multi-touch, with cool, must-have-features, like flick, expand map and pinch.

So with that, my duties as Touch Guy have been fulfilled for 2010!
(And maybe now I can get the marketing lady off my back…)

Until next year,
Touch Guy

Which Touch International touch screens are able to withstand extreme temperatures and are suitable for the automotive industry? – Vivek

Dear Vivek,

Touch Guy knows that making parts for fighter jets is a whole lot easier than meeting the specifications for the automotive market. There are a few automobile tests that we use to evaluate the effects of temperature extremes on LCDs. The best assessment is the Phoenix test where a car is left in the hottest desert temperatures and everything must work properly when started. The weakest link is usually the LCD, which must meet the 85 degree high temperature range without turning black. In extreme heat, touch panels can become puffy, the coordinates can drift and the sunlight can make the display even harder to read. Once passing the Phoenix test, it is on to the Alaska test with low temperatures where a heater is incorporated into the touch panel to keep the LCD warm and toasty.

Traditionally, most automotive GPS systems have been integrated with 4-wire or 8-wire touch technology. These systems required flexible glass to be incorporated into the top plastic layer in order to prevent puffiness on the surface due to extreme changes in temperature. In situations such as this, a better alternative is 5-wire touch technology which is resistant to extreme temperatures, does not need to be recalibrated and costs the same.

The best solution is to use projected capacitive technology because it provides great optics, no temperature drift, never wears out and you will be able to use the cool multi-touch capability to expand or pinch the map size. Touch International is currently integrating proximity sensing technology into the GPS so that the GPS backlight will dim at night until you get your hand nearby and the brightness will increase based on your proximity.

Stay tuned for details!

Until next time,
Touch Guy.