Introduction To Resistive Touch Screen

The resistive touch screen is controlled by pressure sensing.  Resistive touch screen is a main part of the surface,  this is very match the resistance of the film and display screen,  many multilayer structure composite films,  it with a piece of glass or hard plastic flat as grassroots,  surface coated with a layer of transparent .  conductive metal oxide layer,  the above with a layer of surface hardening treatment,  smooth and rubbing the plastic layer,  its inner surface is coated with a layer of coating,   among them there are many tiny transparent ,  isolation point separates two conductive layer of insulation.  When the finger touches the screen,  the two conductive layers have contact at the touch point,  and the resistance changes,  generating signals in the X and Y directions,  and then sending the touch screen controller.  The controller detects the contact and calculates the position,  and then operates according to the mode of the simulated mouse.  This is the basic principle of resistive touch screen technology.  The key to resistive touch screens lies in material technology.  The commonly used transparent conductive coating materials are:

A, ITO, indium oxide,  weak conductor,the characteristic is when the thickness drops below 1800 angstroms,  suddenly becomes transparent,  the light transmittance is 80%. ITO is the main material used in all resistive touch screens and capacitive touch screens. In fact,  the working surface of resistive and capacitive touch screens is the ITO coating.

B. Nickel-gold coating. The outer conductive layer of the five-wire resistance touch screen is made of malleable nickel-gold coating material.  Although the nickel-gold conductive layer has good ductility,  it can only be used as a transparent conductor, which is not suitable for the working surface of the resistive touch screen,  because of its high conductivity and the fact that the metal is not easy to achieve a very uniform thickness.  Therefore,  it is not suitable for the voltage distribution layer,  and can only be used as a probe layer.

Four wire resistance screen

Four-wire resistance analog technology works with two transparent metal layers,  each of which adds a constant voltage of 5V:  one in the vertical direction and one in the horizontal direction.  A total of four cables are required.  Features: high resolution,  high speed transmission response.  Surface hardness treatment, reduce abrasion,  scratch and prevent chemical treatment.  It has smooth surface and fog surface treatment. A correction,  high stability,  never drift.

Five wire resistance screen

Five line resistance touch screen technology . base the voltage field of two direction by precision resistor,  network is added in conductive glass,   we can simply understood as voltage field in two directions and at the same time work,  and the outer conductor used as more than just pure nickel gold conductive layer,  a touch points after testing the inner ITO contact point X axis and Y axis voltage method measured the position of the touch point.

The ITO in the five-wire resistance touch screen needs four lines,  the outer layer only serves as a conductor,  and there are five leads in total for the touch screen.  Features: high resolution,  high speed transmission response.  High surface hardness,  reduce abrasion,  scratch and prevent chemical treatment.  30 million contacts are still usable.  Conductive glass as the substrate medium.  A correction, high stability,  never drift.  The five-wire resistance touch screen has the disadvantage of high price and high requirement for environment.

The limitations of resistive screens
No matter it is a four-wire resistance touch screen or a five-wire resistance touch screen, they are completely isolated from the outside working environment,  not afraid of dust and moisture, it can be used to touch any object,  can be used for writing and drawing,  more suitable for industrial control field and office limited people to use.  The common disadvantage of the resistive touch screen.  that is the outer layer of the composite .  film is made of plastic material.  People who do not know how to use,  too much force or sharp touch may scratch the whole touch screen and lead to scrap.  Within limits,  however,  the scratch will only affect the outer conductive layer,  which is fine for a five-wire resistive touch screen and fatal for a four-wire resistive touch screen.

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