The resistive touch screens: complete record of writing (operation, applications, advantages, disadvantages).
Long considered worthy of a futile and unworkable technology as anti-progressive, touch screens have evolved considerably since their first appearance in the 1970s and have become equally habitual and instinctive as using a credit card or a TV .
New techniques for touch control, the posted limits of some and the evolution of applications have made life difficult for touch screens. The battle saw two main systems survive and hold their own game: capacitive and resistive. This case presents especially resistive touch screens and their technologies.
Operation of resistive technology
How does a resistive screen?
The resistive touch screen consists of two layers traversed by an electric current. The first layer is a glass substrate, above which is a second layer of flexible plastic, which is on the surface of the phone.
These membranes are conductive by the addition of a metal oxide layer, they are kept separated by insulating tiny skates.
When the user presses on a specific point of the screen, flexible plastic surface in contact with the glass screen. The two surfaces in contact, which causes a variation in the electric fields of the two sides, which will be broadcast information and processed by the algorithm built into the unit.
Schematic resistive touch screen
Applications of the resistive screen technology
What is the use made of resistive screens?
Resistive screens are part of our daily lives for over a decade. We cross every day on the street: ATM banking, interactive ticket machines in supermarkets.
The resistive touch screens are also experiencing great success in the field of information, including graphics tablets that require high accuracy and the use of a stylus. Resistive slab team also famous handheld Nintendo DS.
The mobile phone is no exception, although since the advent of the iPhone's capacitive touch screens are all the rage. Many mobile phone manufacturers continue to highlight the resistive technology, without necessarily communicating about it.
To determine whether a cell phone works in resistive or capacitive when no information is available, there are an unstoppable solution: If the unit comes with a stylus, it uses a resistive screen.
For more information: applications for touch screens .
Advantages and disadvantages of resistive
Resistive technology offers a variety of technical advantages that make it a touch screen solution must in some cases figures. Most GPS, PDAs, cash registers and handheld game consoles are equipped with tactile.
The accuracy of a resistive touch screen is potentially higher than for a capacitive screen, including through the use of a stylus which is a tool much thinner and therefore more accurate than a finger.
If the multi touch technology (recognition of multiple simultaneous points of contact) favors a priori use of capacitive touch screen, it is nevertheless possible to adapt the multi touch on a resistive screen. We therefore in theory a perfect equality in this regard.
However the advantage is clearly given to the resistive screens pricing, manufacturing cost is much lower than for a capacitive screen, which has a significant impact on the selling price of the equipment or the quality / price ratio .
Unlike his colleague capacitive screen, resistive touch screen can be used with any surface scoring. Whether it's a pen, a nail, a gloved or bare hand, a resistive pad will respond positively to any form of pressure. Note also a strength of the screen to the presence of water, dust or grease.
The capacitive suffers, however, constraints to consider.
The flexible design of the first layer makes the resistive screens sensitive to scratches, scratches and other damage created by sharp objects.
Another black spot on the average response of resistive, because sometimes you have to press hard, or repeat the same operation before obtaining the desired effect. This sensation may vary according to the "stone age".
Finally, the transparency of a resistive screen is not to serve his image. It typically consumes 20 to 25% of the brightness of the screen. Furthermore the accumulation of layers can produce glare and interfere with viewing angles of the screen.
More information
For fans of technical data, here is a more detailed explanation (borrowed from Wikipedia) the operation of the resistive touch screen technology:
The resistive system consists of a glass plate whose surface is conductive (resistive: ITO). It is covered by a plastic film which is conductive underside (resistive: ITO). These two layers are held apart by spacers microscopic and in addition, an additional layer is added to the surface to prevent scratching (for example, by the pen nibs).
Screen Resistive: layering
An electric current is induced in the two conductive surfaces during the operation. When the user touches with the tip of a stylus (or finger), the pressure begins a contact between two electrified surfaces.
The change in electric fields of the two conductive surfaces to determine the coordinates of the point of contact. Once the coordinates determined by the software processing system is established.
The electrical conductivity of the two sides a little worn at every contact between them (due to electric shocks: micro sparks). Therefore, the accuracy of detecting coordinates of the hit is reduced with use. This technique requires the user to recalibrate the touch pad. This recalibration is to hide the wear of touch by spreading over its entire surface, the errors of the most used areas touch.
We hope you now know everything about the technology of resistive touch screens!
Sources pictures: Mizzenmast, Presence-pc, FrAndroid, Mobilehub
