And cooling, to many friends who have to wear gloves for protection against the cold, this machine will bring a lot of inconvenience. Tough like Lumia 920 to burst the God machine, gloves can also be used without pressure, wooden useful Lumia 920 of the friends, you can also purchase touch screen gloves and AnyGlove drops of love machine introduced before to solve the problem. However, have you ever thought, why do I need to wear a special touch screen gloves to play machine?
First of all we have to say from the touch screen. Common of touch screen has two species, a is resistance screen, through screen pressure induction produced of current changes achieved touch induction, resistance screen is not exists wearing gloves cannot operation of problem of, has this a problem of is most models using of capacitor screen, its principle for, dang capacitor screen work Shi among of conductive sandwich within formed a Exchange farm, dang human touch to screen Shi, in finger and conductor layer Zhijian on will formed a capacitor and produced discharge phenomenon, will has must number of charge transfer to human Shang, Which leads to the edge of the screen electrode voltage changes, exactly where the calculated on this out of touch. Wearing gloves is equivalent to adding a layer of insulating material, makes capacitive touch screen not respond.
Science and children's shoes, below is the test you ever taught secondary school textbooks of the moment:
"Capacitor": a device for storing electric charge, consists of two insulated (or dielectric filler) apart near conductors (poles). The simplest capacitor parallel plate capacitor, as shown in the following figure:
If you have impressions about physics, you may recall, the capacitor charge Q and the ratio of potential u between the capacitor plates called the capacitance of the capacitor, that is:
C=Q/U。
This formula is called the definition of capacitance-type, it tells us that a given capacitor take charge of Q is proportional to the potential difference between the capacitor plates u, and the ratio is a constant. Lumia was reported before 920 on the screen are more sensitive, because Lumia 920 through increasing the electrode voltage led touch-screen NET electric charge in an increase in the number, but, by that, the capacitance of the capacitor has nothing to do with Q, u, but determined by the structure of the capacitor itself. Lumia 920 touch screen: why more sensitive? Let us look at the second decision on a parallel-plate capacitor (where k is the electrostatic constant):
This formula explains the factors affecting capacitance of parallel plate capacitor, or between the plates is the area s-polarization plate spacing d, permittivity ε r. Directly across more of the bipolar plates, space is smaller, the dielectric constant is large, electric capacity c, the greater the value, capacitive screens are also more sensitive.
It also analyses these three factors can be:
1. area s
From the following video seen on the mat after the card (change of dielectric constant and reduced sensitivity) if we are to finger a small area to touch the iPad, touch screen is not responding but if we increase the area of the fingers with the touch screen, c's value changes, capacitive screen in accordance with the corresponding response operations;
2. spacing d
Lumia 920 is more sensitive due to reduce the finger spacing between electric field and conductor: Lumia 920 using ultra-sensitive touch screen displays and sensors are integrated together, which makes the super sensitive touch screen thinner than normal touch-screen for 1 mm thickness (as shown in the following figure). And are at the top of the screen sensor and transmitter location changes, transmitter into the monitor back and sensors into a display of positive, this adjustment has brought improvement of signal to noise ratio, allow the sensor to capture the touch signal weaker; Just Cavalli iPhone 6 Case
3. the permittivity ε r
Different media have different dielectric constant ε r. Such as ε r air is approximately equal to 1, ε r of kerosene is equal to 2, ceramic ε r is equal to 6, ε r of mica is 81. (Incidentally, the dielectric constant is used to describe the insulation, and the metal is a conductor, current can flow through but it's hard to leave, special papers on the dielectric constant of metal, is no longer here to discuss. ）
General of gloves is cannot let touch screen made reaction, main reasons is because gloves is insulation material, between electric parameter is low, and so-called of touch screen gloves actually is in gloves of fingertips location implanted has very fine of metal line, to enhanced has conduction charge of capacity; also, zhiqian mentioned of AnyGlove drops liquid essentially is a electric media, through change has human and touch screen formed of "coupled capacitor" between electric parameter, makes capacitor c of numerical variable big, So we can wear gloves or to operate.
Understanding the principle of touch screen gloves, then love will try to DIY touch screen gloves made, please pay attention to the follow-up article. Just Cavalli iPhone 6 Case
"References"
1. high school of the physical volumes
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