Special-shaped Screen
Infrared Touch Screen
Capacitive Touch Screen
Fast, Accurate, and Intuitive Interaction
Overview
Capacitive touch screen is a common touch technology that uses the principle of capacitance to detect touch position and gesture. It is usually composed of multiple layers, including an insulating layer between at least two layers of conductive material. When a finger or conductive object touches the screen surface, the distribution of the capacitive field changes, and the touch screen determines the touch position by detecting this change. Capacitive touch screens have the advantages of fast response speed, high accuracy, and support for multi-touch, so they are widely used in devices such as smartphones, tablets, and computer monitors.
Structure
The capacitive touch screen uses the current induction of the human body to work. It is a 2-layer composite glass screen. The inner surface of the glass screen is coated with a layer of ITO (coated conductive glass), and the outermost layer is a thin layer of silica glass protective layer. The ITO coating is used as the working surface, and electrodes are drawn out on the four corners. The inner layer of ITO is a shielding layer to ensure a good working environment. When the finger touches the metal layer, due to the human body 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 location information of the touch point by accurately calculating the ratio of these four currents. Therefore, the capacitive touch screen can be recognized by the system with a light touch. The advantage of the projected capacitive touch screen is that it has higher sensitivity, which is also the key point for the success of the iPhone’s virtual screen keyboard.
Working Principle
Generally speaking, the working principle of the touch screen is to report coordinate values, that is, the values of the Charged objects, including human skin, are the charges carried by the human body. Capacitive touch screens are made of materials such as alloys or indium tin oxide (ITO). The charges are stored in strands that are thinner than hair. In the micro electrostatic network, when the finger skin touches the screen, a small amount of current will be absorbed from the contact point, causing a voltage drop in the corner electrodes. The purpose of touch control is achieved by sensing the weak current of the human body. The following figure can clearly illustrate the function of the capacitive screen. working principle:
Advantage
Capacitive touch screens only require touch, not pressure, to generate a signal
Capacitive touch screens require only one or no calibration after production, while resistive technology requires regular calibration
Capacitive solutions have a longer lifespan because the components in a capacitive touch screen do not need to move. In a resistive touch screen, the upper ITO film needs to be thin enough to be flexible so that it can bend down and contact the lower ITO film.
Capacitor technology is superior to resistor technology in terms of light loss and system power consumption
The choice of capacitive or resistive technology depends mainly on the object that touches the screen. If it is a finger touch, capacitive touch screen is a better choice. If a stylus is needed, whether it is plastic or metal, resistive touch screen can do the job. Capacitive touch screens can also use a stylus, but a special stylus is required to work with it.
Surface capacitive can be used for large-size touch screens, and the relative cost is also low, but it cannot support gesture recognition at present: Inductive capacitive is mainly used for small and medium-sized touch screens, and can support gesture recognition
Capacitive technology is wear-resistant, has a long life, and has low maintenance costs for users, so the overall operating costs of manufacturers can be further reduced
Capacitive touch screens support multi-touch technology, and unlike resistive touch screens, they are not slow to respond and are not easily worn.
Shortcoming
Despite the many advantages of capacitive touch screens, there are also some disadvantages:
High Price
Compared with other touch technologies, capacitive touch screens are more expensive to manufacture, which may increase the overall cost of the device.
Affected by the Environment
Capacitive touch screens are easily affected by environmental factors such as moisture, temperature changes, etc., which may cause performance degradation or failure.
Not Suitable for Gloves or Pens
Since capacitive touch screens work by sensing the charge of the human body, using gloves or other non-conductive objects to operate may reduce its sensitivity.
Limited Transparency
In some cases, the insulating and conductive layers of the capacitive touch screen may limit the transparency of the screen and affect the display effect.
Not Suitable for Large-size Screens
Capacitive touch screens may face technical challenges in implementing on larger screens because they require more complex manufacturing processes and higher costs.
Application Scenario
Capacitive touch screens are suitable for various scenarios that require interactive operation and information display. Their flexibility and convenience make them an indispensable part of modern life and work, and they have been widely used in many application scenarios.
Smartphones and Tablets
Capacitive touch screens are the mainstream touch technology for smartphones and tablets. Users can use the touch screen to perform gesture operations, input text, and other operations.
Information Interactive Display
Capacitive touch screens can be used for information interactive display, such as information guides and product displays in public places, shopping malls, or exhibitions. Users can obtain the required information through the touch screen.
Interactive Billboards
In the commercial field, capacitive touch screens can be used for interactive billboards. Through the touch screen, users can interact with the advertising content to enhance the attractiveness and participation of the advertisement.
Self-service Terminals
For example, self-service ticket machines, self-service cash machines, self-service ordering machines, etc., capacitive touch screens can be used for user operation interfaces to simplify user operation processes.
Industrial Control and Monitoring
In the field of industrial automation, capacitive touch screens are widely used in equipment control and monitoring systems. Operators can use the touch screen to operate equipment and set parameters.
Education and Training
Capacitive touch screens can be used in the fields of education and training, such as interactive teaching boards, virtual laboratories, etc., to provide a more vivid and intuitive learning experience.
Medical Equipment
In the medical field, capacitive touch screens can be used as operating interfaces for medical equipment, such as medical diagnostic instruments, patient monitoring equipment, etc.
PRODUCT
CHARACTRISTICS
High Definition
High Sensitivity
Long Service Life
Low Power Consumption
Here is the Product Introduction of a 7-inch
Capacitive Touch Panel
| Size
7 inch |
Contact Type
Multi Touch |
Structure Type
Glass+Glass,etc. |
Surface Hardness
Hard Coating(6H) |
| Aspect Ratio
16:9 |
Interface Type
USB |
Dimension
269.4*211.5mm |
Display Area
246.16*184.72mm |
| Thickness
2.1mm |
Viewing Angle
7 o’clock |
Operating Tem.
-10°C~ 60°C |
Surface Treatment
Anti-glare(AG) |
| Light Trans.
85% |
Storage Tem
-20°C~70°C. |
Contrast Ratio
1000:1 |
Simultaneous Contact
Simultaneous Contact |
Why are Capacitive Touch Screens Popular While Resistive Touch Screens Have Become Unpopular?
The history of resistive touch screens is much longer than that of capacitive touch screens, but why have the resistive touch screens that were once so powerful almost withdrawn from the market after all these years, while capacitive touch screens have become popular? This starts with the advantages of capacitive touch screens.
The biggest advantage of capacitive touch screens is that they can be directly controlled with fingers without the help of any tools. This makes it very convenient for us to operate. In the past, smartphones with resistive screens also needed to prepare styluses. If the stylus was lost, it would be difficult to touch the screen. But with the current capacitive screen, there is no need to worry. Just touch it with your finger and you can operate it smoothly.
Another advantage of capacitive touch screens is multi-touch, which means that multiple touch points on the screen can be operated at the same time. This can be well utilized in games. For example, if we are playing a racing game. The left hand can control the direction of the car, while the right hand can control the throttle and gear of the car. In this way, the playability of the left and right matching games is very high. With the previous resistive screen, we can only touch at a single point. When playing racing games, we can only locate the gear and then control the direction.
If you need to change gears, you can only fix the steering wheel to change gears, which is a very poor gaming experience. When zooming in and out of photos, we can easily zoom to the appropriate size with a capacitive touch screen, while the resistive touch screen needs to call out the zoom in and zoom out buttons step by step, which is very troublesome.
Capacitive touch screens quickly replaced resistive touch screens and occupied the market with these two advantages, but although capacitive touch screens are good, they still have some disadvantages, which are difficult for office and design personnel to accept. One disadvantage is that capacitive touch screens cannot achieve refined handwriting operations. Some business users are used to taking notes by hand, but capacitive touch screens cannot satisfy users.
Another disadvantage is that capacitive touch screens do not perform well in fine painting. Compared with the precise touch of resistive touch screens, resistive screens still have advantages in painting and design. When drawing delicate lines such as hair of characters, resistive screens can be expressed vividly, while capacitive screens are very rough. But in the final analysis, the mass market is still the mainstream market. Designers and business people are a minority after all, so capacitive touch screens are still the world.
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