Nos últimos anos, com o desenvolvimento da tecnologia, vários dispositivos inteligentes aumentaram significativamente, and the application of touch all-in-one machines has once again been expanded. At present, touch all-in-one machines have been widely used in factories, catering, schools, finance, Shopping, museums and other scenarios.
A touch all-in-one machine is composed of advanced electronic components such as a touch screen, motherboard, memory, hard disk, graphics card, etc., and its working principle is no different from that of traditional PCs. According to the size of the touch screen body and in conjunction with software, it can achieve functions such as public information inquiry, advertising display, media interaction, conference content display, offline experience store product display, etc.
As an input device, the touch screen used in all-in-one machines has many advantages such as durability, fast response speed, space saving, and easy communication. Users can quickly obtain the information they want by gently touching the machine screen with their fingers, making human-computer interaction more straightforward.
There are four main types of touch screens on the market today, and the one that suits oneself is generally chosen based on the usage scenario. Então, what are the types and uses of touch screens for all-in-one machines? Take you to analyze and answer.
01 . Resistive touch screen
The main part of a resistive touch screen is a resistive thin film screen that fits well with the surface of the display. This is a multi-layer composite film that uses a glass or hard plastic flat plate as the base layer, coated with a transparent oxide metal (transparent conductive resistor) conductive layer on the surface, and covered with an outer surface hardened, smooth and scratch resistant plastic layer on the top. Its inner surface is also coated with a layer of coating, and there are many small (less than 1/1000 polegada) transparent isolation points between them to isolate the two conductive layers.
When a finger touches the screen, the two conductive layers make contact at the touch point, causing a change in resistance and generating signals in both X and Y directions, which are then sent to the touch screen controller. The controller detects this contact and calculates the position of (X, Y). Many LCD modules use resistive touch screens, which can generate screen bias voltage using four, five, seven, or eight wires and read back the voltage at the touch point.
02 . Capacitive touch screen
Capacitive touch screens work by utilizing the current induction of the human body. When a finger touches a metal layer, a coupling capacitor is formed between the user and the touch screen surface due to the human electric field. For high-frequency currents, the capacitor is a direct conductor, so the finger sucks away a very small current from the contact point. This current flows out 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 corners. The controller calculates the position of the touch point by accurately calculating the ratio of these four currents.
Simply put, it is to divide the screen into blocks and set up a set of mutual capacitance modules in each area, which work independently. Portanto, the capacitive screen can independently detect the touch situation in each area, process it, and simply achieve multi touch.
Comparison of advantages and disadvantages between resistive touch and capacitive touch:
03 . Infrared touch screen
Infrared touch screen uses a dense infrared matrix in the X and Y directions to detect and locate user touch. As shown in the figure, an infrared touch screen is equipped with a circuit board frame in front of the display. The circuit board is arranged with infrared emission tubes and infrared reception tubes on all four sides of the screen, forming a horizontal and vertical cross infrared matrix. When the user touches the screen, their fingers will block the horizontal and vertical infrared rays passing through that position, so they can determine that the touch point has changed to the infrared rays on the touch point and achieve touch screen operation.
04 . Onda acústica de superfície
Surface acoustic waves are a type of ultrasonic wave that propagate mechanical energy waves in shallow layers on the surface of a medium. Directional and small angle surface acoustic wave energy emission can be achieved through a wedge-shaped triangular base. The touch screen part of a surface acoustic wave touch screen can be a flat, spherical, or cylindrical glass plate installed in front of CRT, LIDERADO, LCD, or plasma display screens. The upper left, lower right, and upper right corners of the glass screen are fixed with ultrasonic transmission and reception transducers. The four edges of the glass screen are engraved with highly precise reflection stripes at 45 ° angles, ranging from sparse to dense.
The transmitting transducer converts the electrical signal sent by the controller through the touch screen cable into sound wave energy and transmits it to the left surface. Then, a set of horizontal precision reflection stripes reflect the sound wave energy into vertical energy. The sound wave energy passes through the surface of the screen and is then gathered into a right line by the reflection stripes on the other side to propagate to the X-axis receiving transducer. The receiving transducer converts the returned surface sound wave energy into an electrical signal.
When an object that can absorb sound waves touches the touch screen, it will absorb the sound wave energy on the glass surface where the touch point is located. This change will be reflected in the electrical signal converted by the transducer. After analyzing the electrical signal, the control card can obtain the specific touch position coordinates.
