Grounding Capacitive Touch Screen to Prevent Static Discharge and Phantom Touches

We are having problems with our touch screen acting irregularly. We found part of the problem had to do with the power adapter. It was not very clean coming in and it caused problems. Another issues appear to be related to a bezel which comes close to touching the surface of the touch screen. Our current problem deals with the touch screens phantomly touching the corner buttons on the screen. We remove the bezel and the problem goes away. We assume that the problem has to do with static in the air. The bezel is plastic and the touch screen is capacitive. So it is triggered by an electrical discharge.

Does anyone have any expereince with grounding the touch screen or protecting it from static discharges.

Probably not much use to you but I would guess that the fact that the plastic screen is bezelled might have quite a bit to do with this and would cause difficulties in the way that the touch screen is activated since the charges would be uneven and would tend to move to areas where the plastic cover is less concentrated hence why corner buttons are being activated frequently when not supposed too but that is all I would be able to deduce based on theory of electric charge

What you possibly want is something along the lines of a gold leaf electroscope if there is such an item applied to modern day technology which would allow you to examine the accumilation of static charges across various areas of the panel and subsequently graph the data This might be a highly insulated probe attached to such a device, a highly sensitive goldleaf probe, with possibly some form of equivalent to a bar code scanner with sensors placed possibly on the other side of the instrument which would measure the amount of defection of the leaves and woukd store this data for subsequent analysis later

One method to possibly overcome this might be to create a no touch border around the touch screen itself and encapsulate the outer perimeter of this screen with some type of conductive frame which could then be subsequently earthed to overcome this effect or to condider the type of plastic matarial used which is covering the screen

Alternatively redisign you graphics gui "graphical user interface" to inorperate a border around the screen better known as insets "

Possibly the latter being the better answer to this problem so that you automatically overcome physical deffects which are sometimes un avoidable

If there is a static charge building in the plastic it may be possible the have a similar part made with a plastic that dissipates static, surely some quick testing would confirm or deny it being the source of the trouble.

If you have very dry air in the room (closed room with A/C) where you are that can be a problem.
You can also damage other equipment easy.
Check with a cheap thermo / hydro meter, and use a water mist or other equipment to keep a healthy level for you and your equipment.

Ooooh, oooooooh Dont like the sound of that too much especially with electronic equipment such as pc monitors especially with corrosion of pcb's and component legs, high voltages leading to backlight displays etc and pc switch mode power supplies

Water vapour in the air consistantly could cause more damage Ooooooh

@mark
I mean a equipment to keep the humidity above 30%.
Corrosion from PCB`s and high voltage power supply's do not even have a problem until 90% humidity.
Condensation of the air that is a other story.

Dry air is very damaging to electronic equipment because of the static build up from the air.

I agree with Mark (though, perhaps not with the histrionics -- also, this is not practical as a product requirement -- are you going it include that in the instruction manual "Warning: low humidity can lead to erratic behavior, be sure to apply water mist before operating".

I think Lynn needs a solution that will work in a broader range of environments.

Ah, didn't see your reply, Peter, until after I posted. OK, makes more sense. But, Ipso Facto, because Lynn is pursuing this problem, she must want her product to function in environments where this is a problem, so I would assume she is looking for a solution other than manipulating the environment -- I mean, what if the product is used outside, or elsewhere (such as in outer space or on another planet -- though if that were the case, it's doubtful she would be consulting us

If you look in industrial and professional installations you can find special antistatic floors or floor tiles.
And also the air is monitored not only by temp. bud also the humidity.

And yes in a lot of equipment with touch screens you can find a low humidity and static air warning, that also brings the equipment out of warranty.

I prefer to work on the source of the problem not the result, but that is personal.

I just realized that we might be looking at this problem from different perspectives:

I'm assuming that this is a product under development, and it sounds like, Peter, you are thinking in terms of this being an onsite installation problem (i.e. a _usage_ problem rather than a _development_ problem).

So, Lynn, which is it?

BTW, I assumed production problem because Lynn said

bq). Our current problem deals with the touch screens

But, it could be that there is more than one piece of equipment at the installation site

Yes I have had direct experience with static discharge screwing up the display. Tried all kinds of stuff, then switched to a TI part. Problem solved. You may have to get the touch screen vendor or chip vendor to help you sort it out.

Good luck!

That is what was concerning me condensation especially in the uk

The rest is a little bit of humour somewhat dry Takes a little time to understand my humour You havent worked with people in the uk and they can be ever so funny about all manor of new introductions

I worked for one company and was severely critised for lifting a box above my shoulders Hence my humour

On working for another company point one on the managerial meeting was tiolet paper and we had to have half an hour discussion with severe critisism becuase i found the topic highly amusing,

The obvious answer was simply for a member of staff to ask for some petty cash and quckley nip out and buy some

But there you this how funny people can get about this and what a performance they make about nothing amost to the point where it becomes a sackable offence I have to laugh but its not funny on some occasions becuase thier stupidity in one instance cost me my home So its not that funny

And on another occasion for simply asking a member of Maplins management to get some information for me, a very nasty little individual I was barred from using a Maplins superstore for a year Eventually after I year I then got a formal appology but its to late then youve lost a years bussiness and your income not to mention all the other so and so's you have to with live with who make life unbearable for you Not funny at all

Hence why my circumstances are appalling at the moment

Or change the border settings of the screens gui software and recompile one class file as opposed to cost of change of hardware which can be readilly achieved by one line of code change followed by 5 minutes of compile time

Must be easier and more cost effective than anti static matts, humidifiers, hardware changes to overcome the problem

The beauty of oop programming
[code]

//example if we were talking java

//for example a method on our gui class
//that holds buttons or textfields
//or so on which we add to a frame
// to be displayed on our touch screen

Dimension d = new Dimension (500,600) ;// setscreen size
frame.setSize ( d ) ; // SET FRAMES NEW PARAMTERS FOR LCD

frame.pack ( );
//now we have our window
//resized with an outer border
//around the touch screen
//which wont interact and
// all components have been
//shifted into this space

// its a simple example only
//but illustrates
//how you might achieve this
P
[/code]

Finally recompile just this class only assuming you have oop technology as software

Or if this is html change top and bottom margins, left and right, of the document object or place contents plus gui components into a floating frame object commonly known as an IFrame object

If this was c for example you would ideally have a structure set up which might for example contain data with regards screen sizes and how your screens are layed out each structure pertianing to your differnt objects on your lcd user interface

Hopefully that would be your software model or something along those lines

In other langauges this would be slightly different but never the less the same principles would apply

Or alternativley you might create an additional class which inherrits all methods and instance variables etc etc from a layoutmanager class who's resonsibility it is to describe how the objects and dimensions etc are displayed on the gui

Here you might create a completley different layoutmanager class for each different manufacturer of lcd touch screen or an abstract class which loseley defines methods properties, where you would ensure you left methods suitably open to change layout per individual user specification so as to override the difficulties you are experiancing


On a last point if people looked at java very closely and then considered that this is operable on linux,unix,posix, and windows, relying on the jvm then wouldnt this be far simpler and more cost effective long term because you dont have to recompile for each os although you still have to take on board c and cplus plus as you have to write native methods to interact with the hardware

Not difficult to see why Andoid and java are becomming the leading langauges with Blavkberry not far behind

Worth thinking about isnt it on that note go and have a look at Rassberry PI Also monodevelop www.monodevelop.com Very interesting if you are considering mono for android but price of this is rediculous at the moment some 999 dollars beyond my budgets at present I think they need to realise reality somehow with pricing especially if they want enginneers of this caliber I can just about manage the rasberry Pi

Phew thats me stuffed! ! without christmas dinner excuse me sence of humour Its really dry

WORK THIS OUT YOUSELVES

LETS HOPE THEY READ MY COMMENTS HMM

Ive just finished reading up on some of this and it looks very interesting to say the least so im dead keen to get into this one to find out what this is all about

I don't get it, it is describes as a static discharge issue effecting I assume (should not do that) the display only. So by limiting the screen display area may resolve that issue.

Well if you have so good sleeping tablets and that let's you have a good dream it might. So may a big box of BandAids. Limiting the display area is a bandaid, how small is small enough, a postage stamp.

Worse case you have to test something and that gets past the screen hang issue sure for test purposes, but not a production solution.

The static issue can be solved without resorting to screen size changes. Also depending on who the end user is and the install, you may only have class 1 electrostatic protection, ouch!

Again it can be fixed, we fixed ours and it was certainly challenging, the original vendor part (I think Maxum) we never did get to work, or should I say we tried plan B, which was/is TI.

Good luck.

So, all those seemingly psychotic rants were _humor_? Or was it a mix of humor and a bit of paranoia? Understandable in your current situation. So sad that humans get so wrapped up in a "punitive measures to prevent _repeat offenders_" mentality. In other words, all you stanch conservatives, LIGHTEN the _heck_ UP (it's not as dire as you seem to think!

Obviously there is a minimum size that you could achieve this on But on a fiar size sceen lets for the sake of arguing say this is an 8inch screen which is reasonable size standard common in the market place Even a smart phone screen Then it would make far more sence to simply change the software slightly to give you a superimposed border of margin 5mm than it would say stop production, close a factory, waist all that capital, add to a declining market all becuase of one or two isolated cases where there is possibly excessive static present

Or dont you think so Wouldnt it make more sence to keep a factory open keep people employed still sell and then re invest into your hardware problem without wasting money keeping the market moving and find your perfect solution without losing finances

Isnt this better bussiness sence I know what I would do Question is what would you do

The world isnt perfect Earl niether are people but we have to find a work around the problem Innother words we have to retrain people or in logical terms reprogram people to think differently to overcome andvadapt

We have to find solutions. OTHERWISE the world stops Earl and the human nations roll over and dies

So ive got this lovley track for you Earl and you can listen to this over xmas Earl its start like this, " Oh lord its hard to be humble when as your as good looking as me To know is to love me "

Hope that made you laugh and cheered up your day

Merry Xmas Earl have a good one

Mark

What the hell lets be honest will they ever listen to engineer answer no makes you wonder why the hell we even went to uni college etc doesent it So tell me whats the only answer left

Correct Yes take the pi***sz out of them No other answer is there Yes I know too

Hate them Yes that i do Why because they have done nothing to re educate thier nations Correct decent education

Not even thought about what they have done to thier own countries, own people and then very quickly point there fingers at those who are less fortunate than themselves

Thats why Im so angry

Not what they are Its what they have done to their own

Yes Im working class from the gutter but im prowed of it and why shouldnt I be I worked hard to learn what I know

I am a barcode tester.I test barcode in java program and also test the touch screen of some products.You can use an anti-static protective film to protect it from static discharges.

bq). I am a barcode
tester.I test barcode in java program and also test the touch screen of some products.You can use an anti-static protective film to protect it from static discharges.

I am very interested in the anti-static protective film.Where can i get it?Can you give me more details about it?