During normal touch input your touch is a kind of xy recorder. Your phone can determine where you touched it and than "knows" what you want.
For double touch to wake up your touch panel is however in a low energy state and needs to work together with the proximity sensor.
If you double tap your phone has to determine is it is a wake up call or not.
If you have your phone in your pocket and double tap it t will not wake up because the proximity sensor detects it is in your pocket.
)The wake up could also be done with only 1 tap but then you would often get a false wake up. So to prevent than you need to tap 2 times this reduces the change on a "false" wake up).
So the double touch is works "completely" different than the normal touch input.
To let this work you need a touch panel which works in low energy mode and probably an additional IC.
The problem with non OEM parts is that you actual never know how "original" they are.
If you order a part and it is not very clearly stated it is an original OEM part than it is a "copy".
So words as "original", "after market", "compatible with" are indicators that it is not an original OEM part.
Furthermore the price difference between an original OEM part and a "original", "after market", "compatible" make it tempting to buy a "copy" .
I hope above answers your question.
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02-08-2015 07:30 AM