The working principle of capacitive touch screen feature film is based on human current sensing. When the user's finger touches the screen, a coupling capacitance is formed between the finger and the surface of the touch screen due to the action of the human body's electric field. This capacitance is equivalent to a direct conductor for high-frequency currents, allowing the finger to draw 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 touch screen controller accurately calculates the ratio of these four currents to derive the position of the touch point.
Introduction of touch function film material:
1. membrane
Material: The material of the functional sheet can be a membrane, usually not a single material, but by the double film composite, compared with a single layer of the membrane of the functional sheet, it is more stable and support multi-touch. ITO (Indium Tin Oxide) material is printed on the film, which is a transparent conductive material that can sense current changes.
Thickness: The thickness of the film layer is relatively thin, depending on the design requirements and technical implementation. In ultra-thin capacitive touchscreen feature sheets, the thickness of the film layer can be further compressed to achieve a thinner overall thickness.
2. Glass
Material: Touch function sheets are usually made of high-transmittance, high-strength glass materials. These glass materials not only have good light transmission, but also provide sufficient hardness and scratch resistance.
Thickness: The thickness of the glass layer is relatively thicker than that of the film layer, but again, it will be adjusted according to the design requirements and technical level. Under the trend of pursuing lightness and thinness, the thickness of the glass layer is also decreasing.
Introduction to the advantages and disadvantages of different materials for functional sheets:
Advantages of film
Thin and light: The film layer is relatively thin, which helps to realise the overall thinness and lightness of the touch screen.
Flexibility: Compared with glass, the film layer has a certain degree of flexibility, which can be adapted to curved or irregularly shaped designs to a certain extent.
Cost: In some cases, the cost of the film layer may be lower than the glass layer, helping to reduce overall manufacturing costs.
Disadvantages of film
Durability: Compared to glass, film layers are less durable and susceptible to scratches or abrasion.
Hardness: Film layers are typically less hard than glass layers and may not provide sufficient protection against external impacts.
Advantages of Glass
Hardness: The glass layer has a high degree of hardness and scratch resistance, which effectively protects the touchscreen from scratches and abrasions.
Light Transmission: A glass material with high light transmission ensures clarity and colour reproduction of the touchscreen.
Stability: The glass layer has good stability under changes in temperature, humidity and other environmental factors, and is not prone to deformation or drift.
Disadvantages of Glass
Weight: Compared to film layers, glass layers are heavier, which may not be conducive to achieving a thinner and lighter touch screen.
Cost: In some cases, the cost of the glass layer may be higher than the film layer, increasing the overall manufacturing cost.