Industrial panel pcs are multifunctional devices that can be used for calculation, fitting simulation, tabulation, drawing, selection, discrimination, storage, retrieval, statistics, management, automatic control, artificial intelligence, expert systems, etc. The use of industrial touch panel pc in chemistry is one of the most important achievements of the chemical discipline in recent years. Industrial control pc can be used in every field of chemical engineering, and their superiority and vitality are becoming more and more prominent in the chemical industry. Complex calculations in the chemical discipline, massive chemical information, the complexity and microscopic nature of chemical reactions, the demand for virtual reality, the demand for automation in chemical processes, etc., all require the support of industrial tablet computers. As a bridge between industrial panel pc and programmers, industrial displays are also a topic of concern when ordering industrial tablet computers. Let me briefly introduce industrial touch displays to you. Which is better, a capacitive screen or a resistive screen?
Industrial touch display, industrial monitor, industrial touch all-in-one pc, industrial tablet computer
1. Principle of industrial touch screen:
From the perspective of technical principle, the touch screen is a transparent absolute positioning system:
Therefore, it must have three characteristics:
1. Transparency: The quality of transparent materials will directly affect the visual effect of the touch screen, which is mainly reflected in the reflectivity and clarity of the screen.
2. Absolute coordinate system: Our traditional mouse is a relative positioning system. The positioning only refers to the coordinates of the previous mouse position, while the touch screen points to where it needs to be selected.
This is a relative coordinate system. There is an absolute difference between the two in the nature of coordinates.
3. Detection and positioning: Touch screen technology relies on the sensor under the screen to work, so the positioning principle and the sensor used determine most of the technical indicators of the touch screen,
including response speed, reliability, stability and life.
II. Working principle and advantages and disadvantages of capacitive screen and resistive screen:
1. Capacitive screen touch working mode:
Capacitive touch screen uses the human body's electrical response to work. Its touch screen is composed of a four-layer composite glass screen, and a layer of transparent special metal conductive material is attached to the surface. When the finger touches the touch screen, due to the human body's electric field, the user and the touch screen surface form a coupling capacitor. For high-frequency current, the capacitor is a direct conductor, so the finger absorbs 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 four corners. The controller obtains the position information of the touch point by accurately calculating the ratio of these four currents.
(1) Advantages of capacitive screen:
①Multi-point touch is possible. The multi-point touch capacitive screen currently used on IP can only realize two-point simultaneous touch, which will develop into three-point, four-point, and N-point in the future.
②High positioning accuracy.
*our capacitive screen can work with medical gloves,working gloves.
（2） Disadvantages of capacitive screens:
① The main disadvantage of capacitive screens is drift: when the ambient temperature, humidity, or ambient electric field changes, the capacitive screen will drift, resulting in inaccuracy. For example, when the temperature of the display rises after the power is turned on, it will cause drift: when the user touches the screen while the other hand or one side of the body is close to the display, it will drift; when a large object near the capacitive touch screen is moved, it will drift; when you touch it, if someone comes to watch, it will also cause drift; the drift of the capacitive screen is due to the inherent technical deficiency. Although the environmental potential surface (including the user's body) is far away from the capacitive touch screen, it is much larger than the finger, which directly affects the measurement of the touch position.
② The capacitive screen can only sense the touch of objects with bioelectricity, such as fingers, and the surrounding environment has a fatal impact on it. If your fingers are sweaty, the capacitive screen may no longer be able to provide you with service. If you are in a bathroom full of steam or a sauna, the capacitive screen may go on strike. If you want to use other objects (such as a stylus, toothpick, cotton swab, etc.) to operate the capacitive screen, it will not give you any response. A resistive touch screen is a sensor that converts the physical position of a touch point (X, Y) in a rectangular area into a voltage representing the X and Y coordinates. Many LCD modules use a resistive touch screen, which can use four, five, seven or eight wires to generate a screen bias voltage and read back the voltage of the touch point. A resistive touch screen is basically a film plus glass structure, with the film and glass adjacent to each other on both sides coated with ITO (nano indium tin oxide) coating, which has good conductivity and transparency. When a touch operation is performed, the ITO on the lower layer of the film will contact 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, completing the action of clicking and presenting it on the screen.
2. Working mode of resistive touch screen:
The screen body of the resistive touch screen is a multi-layer composite film, which is composed of a layer of glass or organic glass as the base layer, and a transparent conductive layer (ITO film) is coated on the surface, and a layer of plastic layer with a hardened outer surface, smooth and scratch-resistant is covered on it. Its inner surface is also coated with a layer of ITO, and there are many tiny (less than one thousandth of an inch) transparent isolation points between the two conductive layers to separate them. When the finger touches the screen, the two layers of ITO come into contact, the resistance changes, and signals are generated in the X and Y directions. The controller calculates the XY coordinates of the contact point based on the detected resistance change, and then performs corresponding operations according to this coordinate. Therefore, this technology must use a hard object to apply force to the screen to obtain the touch effect.
(1) Advantages of resistive screen:
① Low cost and good response sensitivity
② Able to adapt to various harsh environments, in any situation (such as going to the toilet, taking a bath, taking a sauna), in any environment (such as rain, snow, high temperature, ultra-low temperature), with anything (such as nails, toothpicks, lighters, tongue) you can accurately touch the resistive screen.
(2) Disadvantages of resistive screen:
① Only single-point touch, which means you can only touch one place at a time. If you touch another place, it will have no effect.
② Since the resistive screen requires a certain amount of pressure, it is easy to cause surface wear over time, affecting the service life of the product;
③ The resistance of the resistive screen is weak and the ability to prevent false operation is poor. Anything touching it will cause an action.
III. The main structural differences between capacitive screens and resistive screens:
Capacitive touch screens can be simply regarded as a screen body composed of four layers of composite screens: the outermost layer is a glass protective layer, followed by a conductive layer, the third layer is a non-conductive glass screen, and the innermost fourth layer is also a conductive layer. The innermost conductive layer is a shielding layer, which plays a role in shielding internal electrical signals. The middle conductive layer is the key part of the entire touch screen. There are direct leads on the four corners or four sides, which are responsible for detecting the position of the touch point. Resistive screens are divided into two types: four-wire resistive screens and five-wire resistive screens. The screen body of the resistive touch screen is a multi-layer composite film attached to the surface of the display. It has a layer of glass or organic glass as the base layer, a transparent conductive layer coated on the surface, and a layer of plastic layer with a hardened outer surface and smooth and scratch-resistant. When a finger is pressed on the touch screen, the two conductive layers come into contact, the resistance changes, and signals are generated in the X and Y directions, which are then sent to the touch screen controller.
4. The difference between the principles of capacitive screen and resistive screen
The capacitive screen senses the current of the human body, while the resistive screen senses the pressure.
Therefore, the capacitive screen will only respond when it is touched with a mobile phone.
It cannot be touched with a stylus or nails, while the resistive screen can be touched with nails or stylus.
5. Comparison between capacitive screen and resistive screen
1. The resistive screen is not affected by dust, humidity and oil, and can be used in low or high temperature environments (evidence shows that industrial tablets using resistive screens can work normally at temperatures from -20℃ to +60℃, and there is no requirement for humidity). Nowadays? There are quite good solutions for wet hand control of capacitive screens, and anti-oil and anti-fingerprint coatings are not exclusive to high-end machines.
* Just as this panel pc with resitive screen, which apply in driving school car in high temperature.
2. Resistive touch screens are relatively cheap due to mature technology and low thresholds. Due to mass production, it is not an exaggeration to say that capacitive screens are currently cheap. At present, the touch technology of capacitive screens has developed by leaps and bounds, and it is no surprise that resistive screens have withdrawn. On the other hand, the shortcomings of resistive screens are fatal. As a result, the outermost layer cannot be made of tempered glass or other hard materials. Therefore, if the resistive screen is not covered with a film, it will be damaged. After all, the hardness is too different, and the screen will be scrapped directly after it is broken (the capacitive screen can continue to be used as long as the touch layer is not damaged).
3. The resistive screen does not support multi-touch, and can be controlled by sharp, insulating objects such as nails and styluses; the capacitive screen relies on the capacitance formed by the human body and the electrode to achieve positioning, and must be touched by the skin or other conductive objects to use. The touch screen cannot be controlled by nails, toothpicks, etc.
