With the increasing use of computers as information sources, touch screens are easy to use, sturdy and durable, fast in response, and space-saving. System designers increasingly feel that using touch screens does have considerable advantages.
It has only been a few years since touch screens appeared on the Chinese market. This new multimedia device has not been touched and understood by many people, including some system designers who are planning to use touch screens. They also treat touch screens as optional. From the perspective of the popularization of touch screens in developed countries and the stage that my country’s multimedia information industry is in, this concept still has a certain universality.
In fact, a touch screen is a device that makes multimedia information or control a new look. It gives a new look to the multimedia system and is a very attractive new multimedia interactive device. The system designers in developed countries and the system designers who are the first to use touch screens in our country have already clearly known that touch screens are no longer an indispensable thing for computers in various application fields, but an indispensable device. It greatly simplifies the use of computers. Even people who don't know anything about computers can still use them at their fingertips, making computers more attractive. It solves the problems that cannot be solved by computers in the public information market.
The three main types of touch screens are: resistive technology touch screens, surface acoustic wave technology touch screens, and capacitive technology touch screens. Each type of touch screen has its own advantages and disadvantages. To understand which type of touch screen is suitable for that occasion, the key is to understand the working principle and characteristics of each type of touch screen technology.
1. Resistive technology touch screen
The main part of the resistive touch screen is a resistive film screen that fits well with the surface of the display. This is a multi-layer composite film. It uses a glass or hard plastic plate as the base layer and has a layer of transparent metal oxide (ITO indium oxide). , Transparent conductive resistance) conductive layer, covered with a hardened outer surface, a smooth and rub-proof plastic layer, and its inner surface is also coated with a layer of ITO coating, there are many small (less than 1/ The transparent isolation point (1000 inches) separates the two conductive layers for insulation. When a finger touches the screen, the two conductive layers are in contact at the touch point. The controller detects this contact and calculates the position of (X, Y), and then operates according to the way of simulating a mouse. This is the most basic principle of resistive technology touch screens.
Since the resistive screen entered the market, it has occupied a vast market with stable quality, reliable quality and high adaptability to the environment. Especially in the field of industrial control, due to the high requirements for its environment and conditions, it shows the uniqueness of resistive screens, making its products occupy 90% of the market in similar touch products and have become mainstream products in the market. Its biggest feature is that it is not afraid of oil, dust, and water.
G-Touch's latest fourth-generation resistive technology touch screen is different from other resistive screen products in that it uses glass as the base plate, which makes the light transmittance higher and the reflective index more suitable for users. At the same time, the conductive layer at the bottom of the glass plate is evenly coated to unload the electrostatic particles adsorbed on the touch screen through the ground wire, which ensures that the touch positioning is more accurate and sensitive, and completely eliminates the drift phenomenon and inaccurate positioning caused by excessive charged particles. The reaction speed is slow, making it longer life (single point continuous use of physical measurement can reach more than 15 years), and it has the ability of maintenance-free, and the degree of scratch resistance has also been greatly improved. It is indeed a product of excellent quality and reasonable price.
1. Features of four-wire resistive screen:
High resolution, high speed transmission response.
Surface hardness treatment reduces scratches, scratches and anti-chemical treatment.
With smooth and matte finish.
One time calibration, high stability, never drift.
When the two transparent metal layers of the four-wire resistance analog technology work, each layer increases a constant voltage of 5V: one vertical direction and one horizontal direction. A total of four cables are required.
2. Features of five-wire resistive screen:
High resolution and high-speed transmission response.
Surface hardness reduces scratches, scratches and chemical treatment.
30 million times at the same point can still be used.
Conductive glass is the substrate medium.
One time calibration, high stability, never drifting.
The five-wire resistance analog technology adds voltages in two directions to the inner metal layer through a resistor network, and measures the position of the touch point by detecting both the voltage and the current. The outer ITO is only used as A total of five cables are required for the conductor layer.
2. Surface acoustic wave technology touch screen
Surface acoustic wave technology uses sound waves to transmit on the surface of an object. When an object touches the surface, it hinders the transmission of sound waves. The transducer detects this change and reflects it to the computer to simulate a mouse.
Features of surface acoustic wave screen:
High clarity and good light transmittance.
Highly durable, good scratch resistance.
One time calibration does not drift.
Responsive.
It is suitable for offices, institutions and places with relatively clean environment.
Surface acoustic wave screens need frequent maintenance, because dust, oil stains or even beverage liquid contaminates the surface of the screen, which will block the wave guide groove on the surface of the touch screen, causing the wave to not be emitted normally, or the waveform changes and the controller cannot recognize it normally, thus affecting For normal use of the touch screen, the user shall strictly pay attention to environmental hygiene. The surface of the screen must be wiped frequently to keep the screen smooth and clean, and a thorough erasure should be done regularly.
Three, capacitive technology touch screen
Use the human body's current induction to work. When the user touches the screen, due to the electric field of the human body, a coupling capacitor is formed between the user and the surface of the touch screen. For high-frequency current, the capacitor is a direct conductor, so the finger draws a small current from the contact point. This current flows from the electrodes on the four corners of the touch screen, and the current flowing through these four electrodes is proportional to the distance from the finger to the four corners. The controller obtains the position of the touch point by accurately calculating the ratio of these four currents. .
Features of capacitive touch screen:
Resistant to most environmental pollutants.
The human body becomes a part of the circuit, so the drift phenomenon is more serious.
Wearing gloves does not work.
Frequent calibration is required.
Not applicable to metal cabinets.
When there is inductance and magnetic induction outside, the touch screen will fail.