Resistive Touch Screen Working Principle and Applications

A resistive touch screen is a sensor that converts the physical location of a touch point (X, Y) in a rectangular area into a voltage representing the X and Y coordinates. Liquid crystal display module uses resistive touch screens, which can use four, five, seven or eight wires to generate screen bias voltage and read back the voltage at the touch point at the same time.

Resistive touch screen is a kind of sensor, which is basically a structure of film and glass. The adjacent side of film and glass is coated with ITO (nano indium tin oxide) coating. ITO has good conductivity and transparency.

When touch operation, the ITO on the lower layer of the film will touch the ITO on the upper layer of the glass, and the corresponding electrical signal will be transmitted through the sensor, sent to the processor through the conversion circuit, and converted into the X and Y values on the screen through calculation, and the point is completed. The selected action is displayed on the screen.

1. Working principle of resistive touch screen

The operation and control of the screen content is mainly realized through the principle of pressure sensing. The screen body of this touch screen is a multi-layer composite film that is very compatible with the display surface. The first layer is the bottom layer of glass or plexiglass, and the second layer is The third layer is a multi-component resin surface layer, which is also coated with a transparent conductive layer, and covered with a layer of hardened, smooth and scratch-resistant plastic layer on the outer surface.

The conductive layer and the glass layer sensor on the surface of the multi-layer resin are separated by many tiny interlayers. The current passes through the surface layer. When the surface layer is lightly pressed down, it touches the bottom layer, and the controller reads the corresponding current from the four corners at the same time. Calculate the distance of the finger position. This touch screen uses two highly transparent conductive layers to form a touch screen, and the distance between the two layers is only 2.5 microns.

When a finger touches the screen, the two layers of conductive layers that are usually insulated from each other have a contact at the touch point. Because one of the conductive layers is connected to the 5V uniform voltage field in the Y-axis direction, the voltage of the detection layer changes from zero to If it is not zero, after the controller detects that it is connected, it performs A/D conversion and compares the obtained voltage value with 5V to obtain the Y-axis coordinate of the touch point, and similarly obtain the X-axis coordinate. It is the most basic principle common to all resistive technology touch screens.

2. Application of resistive touch screen

Touch screen technology first appeared in some industrial and commercial equipment, such as POS terminals, elevator buttons, etc. The touch screen technology facilitates human-computer interaction to a large extent, and the touch screen itself is very durable. These characteristics have made the touch screen technology have a great application and development.

Using touch screen technology, users only need to click the corresponding touch pattern with their fingers to solve the complicated operation problems in the past, which greatly facilitates users. Due to the development of smart phones in recent years, the development of touch screen related industries has been stimulated, and touch screen technology has also been applied to different products.

With the rapid development of mobile Internet, cloud computing and other technologies, people's demand and requirements for touch screen technology are also increasing. It is believed that touch screen technology will appear more and more in different electronic products.

In addition, touch screens also have great room for development in the field of automotive electronics and retailing. According to relevant authoritative surveys, by 2012, the touch screen market for automotive electronics and retailing will reach 2 billion US dollars, accounting for 20% of the total market of the touch screen industry.

At the same time, in the PC industry, due to the continuous development of the Microsoft operating system, touch screen technology will also play a very important role. In addition to the medical field, public facilities, etc., touch screen control technology will be further popularized and has an excellent market expectation.