Database Users

Oil-like stain reflection on screen

After owning the Touch HD for a full month I just noticed that down the middle of the screen there is something which I can best describe as an oil stain. It looks as if there is a liquid in between the glass/plastic screen and the resistive layer that lays on top of it.
The screen works normally and this "stain" can only be observed if I look at how the light reflects of it.
Any idea what happened?

Hi,
I have a small idear. The TFT-Monitor ist touching your Touchscreen. Probeply you pressed something on your HD, that the two Monitor touch each other, that is why it looks like a Water or Oil spot.
This can happen for example, if you are carrying your HD in your trouser pocket.
If you want to try to remove this spot, you have to turn with your both hand the hd, like the right hand turn with the clock and the left hand turn to the other way.
Sorry, my english is not very good for such a discribing. What I mean is like "to contort" or "to skew (up)". But you have to be very carefully. Before you start, remove the Battery

(I'll be incorporating a clearer explanation along the lines of what Dude10 was trying to say)
The effect you're seeing is IDENTICAL to what causes the colours to appear on an oil film actually!
The way the Touch HD screen works is to have the hard glass (polycarbonate plastic actually as far as I'm aware, but that's not important here!) with a squashy resistive sensor layer on the top.
This resistive layer detects touch as an increase in resistance at the spot that's compressed - be that by a finger or a stylus. Because the upper layer can be compressed, it can also be malformed by stronger than normal pressure, such as an object in a pocket. The effect can be more pronounced if your body heat warms up the screen surface making the screen "set" in position rather than spring back as it should do...
The "oil" effect is cause by the reflections of light from the outermost plastic layer and the outermost surface of the hard screen. When the gap is small enough, these reflections can interfere with each other, cancelling and re-inforcing different wavelengths depending on the thickness - hence the tapering of the screen from thinnest to thickest results in a "rainbow"
Now, why explain all this you may ask? Partly because I like science and it fascinated me in school to learn what caused that effect so wanted to share this! (And this also explains why it only presents itself when you look at the light reflections)
Anyway, more importantly, the solution to your problem is to restore the thickness of that part of the touch layer to it's original uncompressed state.
I'd firstly start trying to hold your finger flat against the top of the phone screen (on flat surface, portraint orientation, finger "left to right") then pressing resonably hard (the hard screen should protect the device - if not you're pressing too hard!) slide your finger down the screen from top to bottom trying to keep an even pressure. This should hopefully even out the surface.
Failing this, as Dude10 suggests, take the battery out and use your thumbs (holding with fingers in the battery well) to press and "smear" around the problem area.
Unfortunately, other than this I don't think there's a particular way to remove the effect totally if it doesn't work...
Obviously it's speculation given that you didn't mention how it happened in the first place, but it does sound like it got knocked or pressed by something either in bag or pocket - maybe even a fold in the pouch
Hope you manage to smooth it out!

WhO_KnOwS said:
After owning the Touch HD for a full month I just noticed that down the middle of the screen there is something which I can best describe as an oil stain.
Click to expand...
Click to collapse
Just a long shot, but:
Sometimes a similar effect can be caused when some moisture has got between the layers of a display.
Have you used the phone anywhere damp or very humid ?
Keeping it somewhere warm and dry might be worth a try?
- Steve

Thanks for all the tips. The issue happened when I had the Touch HD in the pouch and in my pocket - so the idea that it was a fold in the pouch holds water.
The funny thing however is that before I saw all of your replies I was already out the door (with the Touch HD back in the pouch and pocket). 5 minutes later when I pulled it out the issue was gone. I am guessing that I reapplied the exact amount of pressure needed or something like that.
Thanks again for the tips and especially to chaosdefinesorder for the nice explanation.

Thx for helping explanation

5 minutes later when I pulled it out the issue was gone.
Click to expand...
Click to collapse
no, i don't think it was gone. check again under a fluorescent light....
i have this on my diamond. my HD is flawless (till now...)
i phoned to a technician and explain the phenomena and he invited me to replace the screen. when i got there, to my complete amazement and embarrassment the stain was gone. only later i discovered that the stain is visible under fluorescent light only.

chaosdefinesorder said:
Unfortunately, other than this I don't think there's a particular way to remove the effect totally if it doesn't work...
Hope you manage to smooth it out!
Click to expand...
Click to collapse
thanks m8, already tried this (on my diamond) and tried now again with both yr methods. no results. the stain is still there...i think only a replacement can solve it.
here u have the paralel thread in diamond forum:
http://forum.xda-developers.com/showthread.php?t=439410&highlight=oily+stain

you can not do it yourself. the best way will be to go to your seller or straight to HTC, because I think you HD still have warranty.
I repaired ones an Diamond and I can tell you, it wasn´t an easy way.

Anyone have a problem with part of the touch screen not registering?

I have an HTC hero and I am having problems with the bottom third of the screen. I cannot "click and hold" in order to drag a program icon, for instance. Instead it just registers the click, and not the hold! Very annoying.
I have MoDaCo custom rom 1.5 on it, but don't think this could be a software/firmware issue. I don't recall it being a problem before, so it appears it has developed a fault!
Nightmare. Anyone experienced anything similar and an easy way to fix it?
James

Hi,
I can't actually help you but i can tell you the first iphones would develop a similar problem with their touchscreen where sensitivity dropped off, especially near the edges. This turned out to be a coating wearing off.
This seems to be happening from time to time with capacitive screens.
If you are sure it's a hardware issue, i wouldn't hesitate to send it back.
Kr,
-Kevin

Have you tried re-starting the phone?

Yes, and it made no difference. But pulling the battery and restarting (I had to do this to get theserial number fot HTC support!) worked!!
Cheers
James

You could also download a "Draw" app to test all areas of the screen.
When I first had mine I had problems hitting the Backspace on the portrait keyboard, I tried a calibrate but I think its better now because my finger knows where to go.
I find my screen seems more responsive when the phone is in my hand, less so if lying on a table. Is this a quirk of a capacitve screen or more to do with the angle of attack?
B

basill said:
I find my screen seems more responsive when the phone is in my hand, less so if lying on a table. Is this a quirk of a capacitve screen or more to do with the angle of attack?
B
Click to expand...
Click to collapse
This. It doesn't seem even remotely responsive when I have it lying down flat on any surface, but as soon as I pick it up it works again.

basill said:
You could also download a "Draw" app to test all areas of the screen.
When I first had mine I had problems hitting the Backspace on the portrait keyboard, I tried a calibrate but I think its better now because my finger knows where to go.
I find my screen seems more responsive when the phone is in my hand, less so if lying on a table. Is this a quirk of a capacitve screen or more to do with the angle of attack?
B
Click to expand...
Click to collapse
The metal bezel actually acts as a grounding point between the capacitive areas that don't have any adjacent space to get a good contact...

seshmaru said:
This. It doesn't seem even remotely responsive when I have it lying down flat on any surface, but as soon as I pick it up it works again.
Click to expand...
Click to collapse
I have noticed the same as you guys

woobit said:
I have noticed the same as you guys
Click to expand...
Click to collapse
You read all the posts in the thread aside from the one with the explanation? (it's just above your post)

I am so sorry, twatamasi

I am so sorry, twatamasi
Click to expand...
Click to collapse
Ladies and gentlemen, it's Oscar Wilde!

woobit said:
I am so sorry, twatamasi
Click to expand...
Click to collapse
Some irony there.

Smart use of Proximity sensor can kill the need for the lock screen

The main need for the lock screen is in the following situation:
Phone is in your pocket (or bag), a hard key is accidentally pressed, the device wakes up. This by itself is not a problem, since without anything else happening the device will go back to sleep, but, if another hard key is pressed while the device is active (screen press can not happen while in pocket, since it's capacitive), the device can start do annoying things.
Now, if the proximity sensor can be designed to switch on when device wakes up, and put it back to sleep (immediately) if device is in pocket/bag, this will kill the need for a lock screen. This is totally possible and just awaits the programmer who wants to make our lives easier...

hm. try pocketShield?
it locks and unlocks your device by use of the light sensor.

Interesting. I will use it for now.
The problem with using a light sensor is that if you use the phone in the dark it won't unlock. Proximity sensor won't have this problem hence it's a better sensor for the task.

Apparently this will happen even without the help of the XDA community...
I've just sent the following email to PocketShield:
Hi,
I would like to know if you are working to utilize the HD2's proximity sensor for unlock (like you did for Omnia). If so, when should we expect a version with this feature ?
Thank you very much.
Click to expand...
Click to collapse
This is their answer:
That’s the idea, but can’t confirm that yet because we are not sure if hooking into the proximity sensor will be possible. Hope yes, as in Omnia2. Just received our new HD2 today and will start to dive into it next week.
Best Regards,
Jim
Click to expand...
Click to collapse

so has anyone tested this for the hd2?
http://www.pocketshield.net/
http://www.youtube.com/watch?v=SpxY9t34TTI

Noam23 said:
The problem with using a light sensor is that if you use the phone in the dark it won't unlock. Proximity sensor won't have this problem hence it's a better sensor for the task.
Click to expand...
Click to collapse
Use TouchLockPro. It has both light and proximity sensor and it is free.

kweiss10 said:
....
http://www.youtube.com/watch?v=SpxY9t34TTI
Click to expand...
Click to collapse
Looks like the guy from the answering machine has found a new job

won't this increase battery drain dramaticly? i think it will becouse it will be constantly looking for light and using that proximity sensor..

Noam23 said:
The main need for the lock screen is in the following situation:
Phone is in your pocket (or bag), a hard key is accidentally pressed, the device wakes up. This by itself is not a problem, since without anything else happening the device will go back to sleep, but, if another hard key is pressed while the device is active (screen press can not happen while in pocket, since it's capacitive), the device can start do annoying things.
Now, if the proximity sensor can be designed to switch on when device wakes up, and put it back to sleep (immediately) if device is in pocket/bag, this will kill the need for a lock screen. This is totally possible and just awaits the programmer who wants to make our lives easier...
Click to expand...
Click to collapse
You are wrong about one important detail though. The screen is very sensitive and can easily be pressed through the lining of your pocket, and even through fairly thick fabric like jeans.

it's a capacative screen...
capacative scree = no stylus/fingernail/penny/spoon
it wont be acvitating throught screen contact.
impossible. (unless you have rrrrrealy thin pants, and the current can pass throught them)

saintnickxiii said:
it's a capacative screen...
capacative scree = no stylus/fingernail/penny/spoon
it wont be acvitating throught screen contact.
impossible. (unless you have rrrrrealy thin pants, and the current can pass throught them)
Click to expand...
Click to collapse
hi, the pants didnt have to be that thin. i think the hd2 screens also vary a lot, in being more or less sensitive. another thing is that people are deifferent when it cames to electric fields. also sweating can affect the display. i startet programs and other touchscreen things already, when the device was in my pocket.
regards mad

jamieeeee said:
won't this increase battery drain dramaticly? i think it will becouse it will be constantly looking for light and using that proximity sensor..
Click to expand...
Click to collapse
In the case of Pocketshield, it won't. Because all sensors only turn on during a short period of time (seconds). Once you unlock or turn off, sensors go to sleep. This is one of the reasons why "auto lock" is not possible, because that will indeed involve a permanent monitoring on the sensors.

saintnickxiii said:
it's a capacative screen...
capacative scree = no stylus/fingernail/penny/spoon
it wont be acvitating throught screen contact.
impossible. (unless you have rrrrrealy thin pants, and the current can pass throught them)
Click to expand...
Click to collapse
You don't know what you're talking about. I didn't say it was sensitive to pressure, but rather that direct contact between skin and the screen is not necessary. Holding my finger on one side of the fabric, and the other side of the fabric touching the screen, this is registered by the screen as a touch EVERY TIME. There are maybe materials that completely isolates the screen, for other materials it probably depends on how thick they are. For me it is certainly possible to influence the screen even through pretty thick cotton fabric (maybe other types of fabric too, I wear mostly cotton), leather, and even paper. Just to test it, I just did a slide to unlock my HD2 through a pile of papers (granted it wasn't a very thick pile, only six sheets of paper thick), and through my leather shoes (this was a little trickier, I had to to make sure that my foot made good contact with the leather at the point where I was sliding my phone across the shoe). i can interact with the screen through normal denim jeans fabric without any problem, and the pocket lining of trousers are usually quite thin, so accidental interaction with the screen seems almost unavoidable if the screen is unlocked in the pocket.
I have actually had some problems a couple of times when the slide to unlock had been deactivated on my HD2. I once took my phone out of my pocket and it was at the confirmation screen for factory reset, and I have actually had the phone hard reset on me once which I suspect may have been caused by the slide to unlock being deactivated. I would never knowingly put an unlocked phone in my pocket, and I wouldn't recommend it to anyone, but you're welcome to do as you please.

X1-owner said:
You don't know what you're talking about. I didn't say it was sensitive to pressure, but rather that direct contact between skin and the screen is not necessary. Holding my finger on one side of the fabric, and the other side of the fabric touching the screen, this is registered by the screen as a touch EVERY TIME. There are maybe materials that completely isolates the screen, for other materials it probably depends on how thick they are. For me it is certainly possible to influence the screen even through pretty thick cotton fabric (maybe other types of fabric too, I wear mostly cotton), leather, and even paper. Just to test it, I just did a slide to unlock my HD2 through a pile of papers (granted it wasn't a very thick pile, only six sheets of paper thick), and through my leather shoes (this was a little trickier, I had to to make sure that my foot made good contact with the leather at the point where I was sliding my phone across the shoe). i can interact with the screen through normal denim jeans fabric without any problem, and the pocket lining of trousers are usually quite thin, so accidental interaction with the screen seems almost unavoidable if the screen is unlocked in the pocket.
I have actually had some problems a couple of times when the slide to unlock had been deactivated on my HD2. I once took my phone out of my pocket and it was at the confirmation screen for factory reset, and I have actually had the phone hard reset on me once which I suspect may have been caused by the slide to unlock being deactivated. I would never knowingly put an unlocked phone in my pocket, and I wouldn't recommend it to anyone, but you're welcome to do as you please.
Click to expand...
Click to collapse
oh, i didn't know it was that sensitive, then, i can really see a need for an apps like this.
but, what about just a normal case? slip it in and out? i mean, i think that COULD solve your problem in a 'no thrills' sorta way... but it wouldnt be as exciting now would it?

madbird said:
hi, the pants didnt have to be that thin. i think the hd2 screens also vary a lot, in being more or less sensitive. another thing is that people are deifferent when it cames to electric fields. also sweating can affect the display. i startet programs and other touchscreen things already, when the device was in my pocket.
regards mad
Click to expand...
Click to collapse
this of course is also true.
taking this into account, i would suggest everybody ground themselves. lol, no... just kidding. i don't even think that would help.

Recommendations for a stylus please

could anyone share any experiences for a good working stylus for the hd2?
this phone is stupendous but alas i have to use it for work and the software we use requires very tiny touches and signature signing.
have tried the ones on e-bay (rubber topped pencil turned upside down)
which is crap...have now tried the htc and dagi ones with the tiny red dot and they are just not cutting it.
has anyone done any homemade experiments or come across a moe "pointy" stylus
toodle pip amigos

I got some, and they were crap...

davidcampbell said:
I got some, and they were crap...
Click to expand...
Click to collapse
Unfortunately you are all too correct!
With the glass screen!
Put a protector on it and they work!

I have been using the dagi long slim one and it works ok, I do have a screen protector on though so maybe this helps... makes selecting text and writing Chinese characters much easier (I use my hd2 to study/translate Chinese so being able to use a stylus to do this is pretty great)... its a bit fiddly to start with as you need to learn how to use it properly, but once you get used to it everything is ok...

Most of the styli are crap, I need something with more of a point, but that's probably not possible. Still waiting for some sort of battery powered pen that offers pin point precision, a guy can dream right...

i'll try to put a screen protector on as suggested and try...
my problem is it's no good mastering the dagi myself as i have to get customers signatures and most people simply can't use it...
it deffo needs something more pointy.
i'm sure i read somewhere on the forum about a guy who was filing something to a point till it stopped working???
i'm so frustrated as this is the only phone in 8 years that uses my works software flawlessly...except stylii

I have ordered the official htc stylus 400.
arrives in 2 weeks and i'll post comments.
read a review after ordering that it actually scratches the screen!
I guess i should have waited for the 400/2 version!
look on the bright side, will probably misplace it by the second day anyway

I've tried using my DS stylus but that doesnt work, seems like it was made for bigger objects to come in contact with the screen (ie fingers).

ILLEATYAFACE said:
I've tried using my DS stylus but that doesnt work, seems like it was made for bigger objects to come in contact with the screen (ie fingers).
Click to expand...
Click to collapse
It`s not about the size of objects. HD2 has capacitive screen.
"A capacitive touchscreen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO).[2][3] As the human body is also a conductor, touching the surface of the screen results in a distortion of the body's electrostatic field, measurable as a change in capacitance. Different technologies may be used to determine the location of the touch. The location can be passed to a computer running a software application which will calculate how the user's touch relates to the computer software."
Wikipedia

thanx for input guys..i least i know about capacitive screens now thanx to kregowski...although i sorta knew.
so if someone could come up with a small pointy thing that gives off some sort of electro staticy stuff...we in..
the search continues

Got the dagi (10 euro from Hong Kong). I am not amused... Touching the screen with the complete tip flat on the screen is annoying to get used to. Often only the side of the tip touches the screen.
When the tip is flat on the screen (which it should) it just does not feel OK. Not "delicate".
Which the screen responsiveness lowered and the tap-reaction time increased (which I did just to be able to get some decent fingertyping results) the dagi does not function adequate. I have to aim more accurate then with my fingers and have to press the dagi on the screen.
Putting the screensettings to default (which I did not try yet) reinstates all the drawbacks in the other functionalities.

touchscreen unresponsive when phone is on flat surface

sometimes my phones touchscreen becomes unresponsive when its flat on its back on a table for example. I unlock the screen with the trackpad or power button so that the screen comes on. Then when i try to slide the lockscreen it doesnt do anything. When i begin sliding the bar from the total edge of the screen it sometimes works.
Usually i just have to pick up the phone to get the touchscreen working again. actually, when i even lift up the phone the slightest bit, it works again.
Weird right?
anyone else experiences this issue ?

I assumed it was designed to work like this. Makes me move my phone rather than just slide to snooze the alarm then go back to sleep.

Same here. I think it has to do with the capacative toucscreen.
Sent from my HTC Vision using XDA App

wileykat said:
I assumed it was designed to work like this. Makes me move my phone rather than just slide to snooze the alarm then go back to sleep.
Click to expand...
Click to collapse
you're saying you move your phone to snooze the alarm? didnt know it could do that, gonna try that out tomorrow morning
forgot to mention the issue is not ROM specific. I have witnessed it on virtuous, CM, MIUI, stock

Ive had this problem as well. Slightly annoying!

I don't think its a design issue..
you don't have to lift your phone to get the screen to respond.
notice that it is enough just to touch the body of the phone to make the screen responsive again..
for me its very annoying, especially not being able to snooze the alarm in the morning

Let me point out that this happens with my G1 also so its not just the G2.

Yeah, there are a few discussions about this on the forums already. It's most likely a capacitance issue. When your phone is just sitting on a table and you touch the display, you may not create enough capacitance with the touchscreen for it to register as a touch (as opposed to resistive touchscreens which needed only physical contact but were less accurate as a result). Touching the body of the phone basically creates a common ground or voltage reference point for the phone, allowing your finger to create the needed amount of capacitance (in technical terms, no longer a floating ground). Whenever I touch the screen while the phone is lying on a table, I just always make sure to rest either my thumb or ring finger on one of the edges.
A lot of factors will also come into play---whether or not your phone is in a case, type of material the phone is resting on, the level of humidity in the air, even potentially the type of shoes you are wearing. This is why sometimes it works and sometimes it doesn't.

ianmcquinn said:
(...) Touching the body of the phone basically creates a common ground or voltage reference point for the phone, allowing your finger to create the needed amount of capacitance (in technical terms, no longer a floating ground). (...)
Click to expand...
Click to collapse
yes! I just figured this out myself. merely touching the body of the phone makes the screen respond to my fingers.
well in that case its not really a big problem. from now on i just touch teh body with my middle finger while sliding with my index finger =D

liory said:
notice that it is enough just to touch the body of the phone to make the screen responsive again..
for me its very annoying, especially not being able to snooze the alarm in the morning
Click to expand...
Click to collapse
Will give this a go tomorrow, I hope it doesn't work!!!.... I'm gonna be forever snoozing with 2 fingers now!!!

This seems to be temperature related (and it doesn't happen on a mytouch 3g)
I live in Minnesota and I deliver pizza. When I would need to call a customer to get into an apartment building, I would set the phone on top of the pizza bag and dial with one hand.
When I first got my G2 (early november) I had no problems doing this, then one day it wouldn't respond at all to touch. I still had my old mytouch 3g with me because the old number wasn't ported yet, and I was able to use that to make the call. It wasn't until later that I realized that the problem was caused by the cold and that I needed to touch the metal part to make it work, so I thought that the touchscreen on my 2 week old G2 had just died.
At room temperature the touch screen always works (I can silence the alarm while it's sitting on the table), but temperatures below 50F cause problems

I started noticing this as well. Sometimes I'll hit the power button to turn my phone on from idle-state and then I'll drag the unlock button with to no avail! But then again, I do use my thumb to do it so maybe the capacitance by using the thumb isn't good enough to unlock it.
I use my phone at work a lot so in order to text while being discreet, I usually have the phone in my right hand and text / unlock the phone using my thumb. I doubt it is a defect but it had me worried too. Guess I'm not the only one experiencing this. (Although I must say, dragging my thumb to swype and using the side of my thumb probably is the reason why it sometimes doesn't work)

Back when I had my g1 it did the same thing and experience this on my g2....if its laying down its like it thinks its just on in your pocket so the touch seems limited
Sent from my T-Mobile G2 using XDA App

Elegy said:
sometimes my phones touchscreen becomes unresponsive when its flat on its back on a table for example. I unlock the screen with the trackpad or power button so that the screen comes on. Then when i try to slide the lockscreen it doesnt do anything. When i begin sliding the bar from the total edge of the screen it sometimes works.
Usually i just have to pick up the phone to get the touchscreen working again. actually, when i even lift up the phone the slightest bit, it works again.
Weird right?
anyone else experiences this issue ?
Click to expand...
Click to collapse
Not weird. TOTALLY normal and expected.
It is because it has a CAPACITIVE TOUCHSCREEN.
This means that when you touch the screen, your finger is actually COMPLETING AN ELECTRIC CIRCUIT.
When the phone is lying on a table and you touch it, you are NOT completing the circuit since you are NOT touching the phone's body.
When the sensor is on, there is an electrical difference between the surface of the screen and the body of the phone. When you touch BOTH, you alter the electric field in that localized area of the screen. The sensor detects the change in voltage and determines the location of the contact.

dhkr123 said:
Not weird. TOTALLY normal and expected.
It is because it has a CAPACITIVE TOUCHSCREEN.
This means that when you touch the screen, your finger is actually COMPLETING AN ELECTRIC CIRCUIT.
When the phone is lying on a table and you touch it, you are NOT completing the circuit since you are NOT touching the phone's body.
When the sensor is on, there is an electrical difference between the surface of the screen and the body of the phone. When you touch BOTH, you alter the electric field in that localized area of the screen. The sensor detects the change in voltage and determines the location of the contact.
Click to expand...
Click to collapse
So how do I adjust the sensitivity? As I understand it I could increase the voltage to the screen making it easier to complete the circuit...such as through thin gloves.....
Sent from my HTC Vision using XDA App

dhkr123 said:
Not weird. TOTALLY normal and expected.
It is because it has a CAPACITIVE TOUCHSCREEN.
This means that when you touch the screen, your finger is actually COMPLETING AN ELECTRIC CIRCUIT.
When the phone is lying on a table and you touch it, you are NOT completing the circuit since you are NOT touching the phone's body.
When the sensor is on, there is an electrical difference between the surface of the screen and the body of the phone. When you touch BOTH, you alter the electric field in that localized area of the screen. The sensor detects the change in voltage and determines the location of the contact.
Click to expand...
Click to collapse
This is mostly true.
Put the phone on the table and dont touch it and try to swipe to unlock.
No touch a finger on the phone body and do it again, itll work.
Doesn't seem to always fit that behavior, but more often than not.

TheNewGuy said:
So how do I adjust the sensitivity? As I understand it I could increase the voltage to the screen making it easier to complete the circuit...such as through thin gloves.....
Click to expand...
Click to collapse
You don't. You should NOT even if you could. It would not work as you expect since it is NOT a matter of sensitivity, but of CONDUCTIVITY.

klmsu19 said:
This is mostly true.
Put the phone on the table and dont touch it and try to swipe to unlock.
No touch a finger on the phone body and do it again, itll work.
Doesn't seem to always fit that behavior, but more often than not.
Click to expand...
Click to collapse
It is not "mostly" true, it is PRECISELY true.

dhkr123 said:
It is not "mostly" true, it is PRECISELY true.
Click to expand...
Click to collapse
No reason for the condescending tone in every post (or if it's not your intention to be condescending, you may want to restrain your constant use of caps). You had stated:
dhkr123 said:
This means that when you touch the screen, your finger is actually COMPLETING AN ELECTRIC CIRCUIT.
When the phone is lying on a table and you touch it, you are NOT completing the circuit since you are NOT touching the phone's body.
Click to expand...
Click to collapse
Someone was just pointing out that if this was "precisely" true as you put it, then the screen should never be responsive if you aren't touching the phone's body (since the circuit is, based on your reasoning, still broken). This isn't the case though since it does work sometimes. How could your statement be precisely true if it's known to be false sometimes (hence the "mostly true" comment)?
And it's actually not true. You are not completing an electric circuit. No current flows from your finger into the screen and no components within the phone are electrically coupled because of your touch. As you stated, you are altering the electric field when you touch the screen. This results in a change in capacitance in that area. Note, this change occurs even when you are not touching the phone's body, just to a different degree. Touching the phone will typically increase the amount of capacitance as opposed to when you are not though (since you are basically "grounding" yourself to the phone). The more capacitance there is, the easier it is to measure. If there is too little capacitance, the touchscreen's microcontroller will not register the change at all. Even if it does register the change, there will be additional filtering that occurs to that raw data either in the microcontroller itself or in software (or both).
This is why the screen works sometimes when you touch it without touching the rest of the phone. You are still causing a change in capacitance. The amount of change depends on numerous factors (this is what I stated in an earlier post). These factors effect how grounded both you and the phone are relative to earth ground (in the electrical sense, not geographical). Typically speaking though, if you are relatively close to earth ground, then you will be able to use the screen without touching the body of the phone. For example, someone stated earlier that the screen doesn't work when it's cold. Cold weather results in lower humidity/drier air and you being less grounded (basically why people see an increase in static electricity as well). Chances are that the touchscreen would work again without the touching the phone's body if you had physically been touching a large piece of metal with your other hand (to help ground you).
So in response to the other question posed, yes, technically by raising the voltage level to the touchscreen, it may result in a more sensitive screen since there will be a larger increase in capacitance when you touch it. It may also reduce the life of the touchscreen though, if not damage it completely, so not a good idea. It would be better to figure out the filtering mechanism if possible and adjust that in software. Not sure if any devs have looked into it (though my guess is that if it was simple, it would have been done already).

I am so happy I found this thread..
Lately I thought my touchscreen was broken because I was unable to snooze my alarm in the morning (just as some of you seem to have been trying to do).
I think it's temperature related as suggested by the person who mentioned pizza delivery.. and I think this because it only happens on mornings where I've left the bedroom window open and it's very cool. My phone is often on a cold wooden surface. however even picking up the phone doesn't seem to help (I'll have to pay more attention next time) but after a few moments of struggling it eventually works (probably warms up in my hand and gets a better circuit).
I can also vouch that the screen works great with just a single finger on a flat surface, provided it's room temperature. I don't need to touch the body at all, and I do this a lot without issues (aside from cold mornings waking up to my alarm).