Capacitive Touch Screen

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Black93300ZX

Senior Member
Jul 23, 2008
1,633
6
Brooklyn
A capacitive touchscreen panel is coated with a material, typically indium tin oxide that conducts a continuous electrical current across the sensor. The sensor therefore exhibits a precisely controlled field of stored electrons in both the horizontal and vertical axes - it achieves capacitance. The human body is also an electrical device which has stored electrons and therefore also exhibits capacitance. When the sensor's 'normal' capacitance field (its reference state) is altered by another capacitance field, i.e., someone's finger, electronic circuits located at each corner of the panel measure the resultant 'distortion' in the sine wave characteristics of the reference field and sends the information about the event to the controller for mathematical processing. Capacitive sensors can either be touched with a bare finger or with a conductive device being held by a bare hand. Capacitive touchscreens are not affected by outside elements and have high clarity. The Apple iPhone is an example of a product that uses capacitance touchscreen technology: the iPhone is further capable of multi-touch sensing.
Capacitive sensors work based on proximity, and do not have to be directly touched to be triggered. In most cases, direct contact to a conductive metal surface does not occur and the conductive sensor is separated from the user's body by an insulating glass or plastic layer. Devices with capacitive buttons intended to be touched by a finger can often be triggered by quickly waving the palm of the hand close to the surface without touching.

The HTC/T-Mobile G1/Dream is also equipped with a capacitive touch screen.
 

yodafone

Senior Member
Dec 15, 2004
106
5
Without opening up the phone, there are several ways to find out if a phone uses a capacitive or resistive (i.e. pressure-sensitive) screen.

1. Look at the screen off-angle in bright light. You may be able to see a grid of dots that looks something like this and extends over the entire screen surface:
. . .
. . .
. . .
If you can, it's probably not a capacitive screen.

2. Can the screen be operated by a non-conductive object i.e. a toothpick?
If so, it's probably not a capacitive screen.

3. Does the device come with a stylus/"plectrum" and does it require screen calibration?
If it does, it's probably not a capacitive screen.

No mass-market WM device to date has a capacitive touchscreen, including the X1. The first post of this thread will help you understand why: http://discuss.pocketnow.com/showthread.php?threadid=23389
 
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orelsi

Senior Member
Jan 1, 2009
1,655
1
No, Xperia is like the rest of our phones has resistive screen. It can be very sensitive, but stylus will be your main indication. I have LG Prada that has capacitive screen and LG Viewty that has a resistive one.

No? So, you have spied on me using my phone and know that it is not more sensitive? Pffft...
 

Biker1

Senior Member
Oct 28, 2008
3,550
1,290
Do capacititve screens have a separation issue like some of the HTC resistive screens have?
Where the layers of a resistive screen including the digitizer start to separate causing a rectangular shape in the center that looks like oil on water.
Has happened to me and many others where the screen eventually has a complete failure.
I do know that the capacitive screens on the iPhone are prone to breakage due to the fact that it has a glass surface.
The resistive screen of the Diamond is less prone to breakage because it has a plastic type film on the surface.
Btw, my screen is pretty sensitive, whether using the stylus or touch.
 
Last edited:

proace069

Member
Jan 31, 2009
40
1
You can tweak your resistiv screen by allign screen.

If you dont press the screen and move little circles between the arrow you can make screen more sensitiv


Sorry for my english cause i am german :)
 

Dr.Gonz0

Senior Member
May 21, 2007
346
32
A capacitive touchscreen panel is coated with a material, typically indium tin oxide that conducts a continuous electrical current across the sensor. The sensor therefore exhibits a precisely controlled field of stored electrons in both the horizontal and vertical axes - it achieves capacitance. The human body is also an electrical device which has stored electrons and therefore also exhibits capacitance. When the sensor's 'normal' capacitance field (its reference state) is altered by another capacitance field, i.e., someone's finger, electronic circuits located at each corner of the panel measure the resultant 'distortion' in the sine wave characteristics of the reference field and sends the information about the event to the controller for mathematical processing. Capacitive sensors can either be touched with a bare finger or with a conductive device being held by a bare hand. Capacitive touchscreens are not affected by outside elements and have high clarity. The Apple iPhone is an example of a product that uses capacitance touchscreen technology: the iPhone is further capable of multi-touch sensing.
Capacitive sensors work based on proximity, and do not have to be directly touched to be triggered. In most cases, direct contact to a conductive metal surface does not occur and the conductive sensor is separated from the user's body by an insulating glass or plastic layer. Devices with capacitive buttons intended to be touched by a finger can often be triggered by quickly waving the palm of the hand close to the surface without touching.

The HTC/T-Mobile G1/Dream is also equipped with a capacitive touch screen.

interesting... I didn't know that
 

danger-rat

Senior Member
Feb 14, 2010
2,218
316
USA
1. Look at the screen off-angle in bright light. You may be able to see a grid of dots that looks something like this and extends over the entire screen surface:
. . .
. . .
. . .
If you can, it's probably not a capacitive screen.


Not necessarily true. The Nexus One has a capacitive screen and also has the dots...


Sent from my Nexus One using XDA App
 

eulalie

New member
Dec 19, 2007
2
0
Multi-touch

So.. I guess I'm going to show my ignorance, but here is my question.

There are several posts on several sites talking about how you can't do multi-touch unless you have a capacitive screen. Then I go to Pandawill and look at the G10. It says it's a resistive screen but there are videos of it doing pinch-to-zoom.

Can someone help me understand how multi-touch relates to the screen type?

Sorry if i'm too much of a n00b :confused:
 

ozy944

Senior Member
Sep 25, 2009
139
0
Hobart
Sorry to add fuel to fire but a capacitive screen will always be more sensitive (speaking purely about the physics of it) than a resisitive screen.

Why?
Capacitive screens rely on charge and comparative charge of two bodies. In some instances, capacitive screens can work without the finger actually touching the screen.
Resistive screens rely on a minute deflection from contact to connect two conductive layers. You can touch a resistive screen lightly enough to not result in a UI interaction. Resisitve screens can be tweaked to work at a very high sensitivity but still not as sensitive as a capacitive screen.

Go ahead, compare two phones with opposing screen tech side by side. I thought nothing could be as responsive as my Topaz till I bought a Nexus, then Desire (which have other issues btw! )

Sorry but thats the blunt science behind it. Bear in mind the perception of responsiveness to touch can very well depend on the quality/smoothness of the software written or the user interface.

Source:
HTC Touch Diamond 2 vs. HTC Desire
Source 2:
My university degree.
 

ozy944

Senior Member
Sep 25, 2009
139
0
Hobart
Sorry for the double post but to answer your question,

Yes resistive screens can be used to provide multi touch support. Where this support isnt built into the drivers for the digitizer, its a lot harder. Bear in mind most older phones were launched before the mainstream advent of multi touch. Thus no drivers...only brilliant minds at XDA :)

However, using a resisitve touch screen to provide multi touch has some serious drawbacks, mainly on smaller screens.

I hate to break it to you but the reason behind this is actually the size of your "pinch" fingers with respect to screen size.

Multi touch on a small resistive screen cause deflection at multiple points on the digitizer but due to the reliance on deflection, the software will inevitably struggle to understand what sort of multitouch gesture you're trying to do! Your fingers with relation to screen size are simply too big!

When you have a bigger screen or a well designed digitizer + software, it can determine positions of multiple points much more accurately, thus allowing multi-touch.

So.. I guess I'm going to show my ignorance, but here is my question.

There are several posts on several sites talking about how you can't do multi-touch unless you have a capacitive screen. Then I go to Pandawill and look at the G10. It says it's a resistive screen but there are videos of it doing pinch-to-zoom.

Can someone help me understand how multi-touch relates to the screen type?

Sorry if i'm too much of a n00b :confused:
 

eulalie

New member
Dec 19, 2007
2
0
Sorry for the double post but to answer your question,

Yes resistive screens can be used to provide multi touch support. Where this support isnt built into the drivers for the digitizer, its a lot harder. Bear in mind most older phones were launched before the mainstream advent of multi touch. Thus no drivers...only brilliant minds at XDA :)

However, using a resisitve touch screen to provide multi touch has some serious drawbacks, mainly on smaller screens.

I hate to break it to you but the reason behind this is actually the size of your "pinch" fingers with respect to screen size.

Multi touch on a small resistive screen cause deflection at multiple points on the digitizer but due to the reliance on deflection, the software will inevitably struggle to understand what sort of multitouch gesture you're trying to do! Your fingers with relation to screen size are simply too big!

When you have a bigger screen or a well designed digitizer + software, it can determine positions of multiple points much more accurately, thus allowing multi-touch.

Right.. I get that pinch is tougher on a small screen thats less sensative. The question was posed because there isn't a, what i consider to be cheap (in the 250$ or less range), 10 in capacative android tablet on the market.

If i venture in the the flatpad/apad/epad world... is it the case that it is impossible for that type of screen to do multi-touch? From your response I'm hearing that it IS possible to do multi-touch on a flatpad.. given that there are drivers supporting it. I'd love to have a capacative screen but from what i've seen online, they're going to be twice the cost or more.
 

ozy944

Senior Member
Sep 25, 2009
139
0
Hobart
Right.. I get that pinch is tougher on a small screen thats less sensative. The question was posed because there isn't a, what i consider to be cheap (in the 250$ or less range), 10 in capacative android tablet on the market.

If i venture in the the flatpad/apad/epad world... is it the case that it is impossible for that type of screen to do multi-touch? From your response I'm hearing that it IS possible to do multi-touch on a flatpad.. given that there are drivers supporting it. I'd love to have a capacative screen but from what i've seen online, they're going to be twice the cost or more.


A dilemma huh? To be brutally honest, most budget oriented tablets are simply that: budget oriented. A lot of them (im trying not to generalize) and Ive tried a fair few are poorly implemented tablets and more trouble than they are worth. Slow, laggy, bad battery life. You'll have enough issues to simply forget the lack of multi touch.

If I was after a tablet, hard as it may be, Id wait till some big players launch a proper device...that'll lead to better adoption and less half baked tablets that are more tech demo than retail product.

Bear in mind the lack of android market access on almost all of these tablets. Due to their generic nature, dev work is also a no-go. Everybody and their friends and family have a device out with a costomised, baked os that its not even funny!


Id check out the galaxy tablet from samsung or wait for it to make some waves and bring forth better implemented copycat products :)
 
Last edited:

norodaigh

Senior Member
Feb 1, 2010
99
1
Lurgan
Without opening up the phone, there are several ways to find out if a phone uses a capacitive or resistive (i.e. pressure-sensitive) screen.

1. Look at the screen off-angle in bright light. You may be able to see a grid of dots that looks something like this and extends over the entire screen surface:
. . .
. . .
. . .
If you can, it's probably not a capacitive screen.

2. Can the screen be operated by a non-conductive object i.e. a toothpick?
If so, it's probably not a capacitive screen.

3. Does the device come with a stylus/"plectrum" and does it require screen calibration?
If it does, it's probably not a capacitive screen.

No mass-market WM device to date has a capacitive touchscreen, including the X1. The first post of this thread will help you understand why: http://discuss.pocketnow.com/showthread.php?threadid=23389

The HTC HD2 is a capacitive touch-screen phone, was mass marketed on WM and has the dots (not horizontally but diagonally). Dont talk about it if you dont know about it.

http://crave.cnet.co.uk/mobiles/htc-hd2-first-windows-mobile-with-capacitive-touchscreen-49303837/
 

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    A capacitive touchscreen panel is coated with a material, typically indium tin oxide that conducts a continuous electrical current across the sensor. The sensor therefore exhibits a precisely controlled field of stored electrons in both the horizontal and vertical axes - it achieves capacitance. The human body is also an electrical device which has stored electrons and therefore also exhibits capacitance. When the sensor's 'normal' capacitance field (its reference state) is altered by another capacitance field, i.e., someone's finger, electronic circuits located at each corner of the panel measure the resultant 'distortion' in the sine wave characteristics of the reference field and sends the information about the event to the controller for mathematical processing. Capacitive sensors can either be touched with a bare finger or with a conductive device being held by a bare hand. Capacitive touchscreens are not affected by outside elements and have high clarity. The Apple iPhone is an example of a product that uses capacitance touchscreen technology: the iPhone is further capable of multi-touch sensing.
    Capacitive sensors work based on proximity, and do not have to be directly touched to be triggered. In most cases, direct contact to a conductive metal surface does not occur and the conductive sensor is separated from the user's body by an insulating glass or plastic layer. Devices with capacitive buttons intended to be touched by a finger can often be triggered by quickly waving the palm of the hand close to the surface without touching.

    The HTC/T-Mobile G1/Dream is also equipped with a capacitive touch screen.
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    1
    Without opening up the phone, there are several ways to find out if a phone uses a capacitive or resistive (i.e. pressure-sensitive) screen.

    1. Look at the screen off-angle in bright light. You may be able to see a grid of dots that looks something like this and extends over the entire screen surface:
    . . .
    . . .
    . . .
    If you can, it's probably not a capacitive screen.

    2. Can the screen be operated by a non-conductive object i.e. a toothpick?
    If so, it's probably not a capacitive screen.

    3. Does the device come with a stylus/"plectrum" and does it require screen calibration?
    If it does, it's probably not a capacitive screen.

    No mass-market WM device to date has a capacitive touchscreen, including the X1. The first post of this thread will help you understand why: http://discuss.pocketnow.com/showthread.php?threadid=23389
    1
    Wrong. Amoled phones are highly sensitive as its hardware screen is glued in together in one.

    Did you even look at the date that was posted?
    1
    A quick test to check the size of your own bollocks in relative terms to your devices sensitivity though its capacitive ( or not ) touch screen.

    If you can use your finger nail ( no skin ) then it is sensitive ( big bollocks )

    If not then its not very sensitive ( little bollocks )

    Just saying......

    Sent from my S1 using xda premium