The touch panel is also called touch screen. Any electronic device that you see, which can realize human-computer interaction basically uses touch screen technology and touch panel. It enables a simple and convenient way of human-computer interaction, bringing convenient interactive equipment to everyone's life and work.
The touch panel was first derived from a brief article describing capacitive touch screens by E.A. Johnson in 1965, followed by an in-depth article with pictures and truth in 1967. In 1970, two engineers from CERN (European Council for Nuclear Research) invented the transparent touch panel in the early 1970s and put it into use in 1973. Later, in 1975, an American George Samuel Hurst invented the resistive touch screen panel and obtained the US patent (#3,911,215), and put it into commercial in 1982.
From the perspective of technical principles, the touch screen is a set of transparent absolute positioning system. First of all, it must be transparent; secondly, it is absolute coordinates, which is where the finger touches. Unlike a mouse, which requires a cursor for relative positioning, so it's very easy to get distracted because you have to keep track of where the cursor is.
The structure is usually covered with a pressure plate on a semi-reflective liquid crystal panel (ITO transparent conductive electrode), which is highly sensitive to pressure. When an object is pressed on it, a current signal will be generated and the position of the pressure source will be determined, which can be dynamically tracked. This is the on-cell technology reported by the media. There are also In cell Touch touch components integrated in the display panel, so that the panel itself has the touch function, and the touch effect and application can be achieved without additional bonding and assembly with the touch panel, mainly Apple is researching.
Next, we mainly introduce the differences and principles of different touch technologies from the perspective of transparency and positioning methods.
Differentiating touch screens from technical principles can be divided into five basic categories: vector pressure sensing technology touch screens, resistive technology touch screens, capacitive touch screens, infrared technology touch screens, and surface acoustic wave technology touch screens.
Among them, the vector pressure sensing technology touch screen has withdrawn from the stage of history. The infrared technology touch screen is cheap, but its frame is fragile, easy to produce light interference, and distortion under the curved surface. Surface acoustic touch screen almost solves all the defects of the touch screen, clear and not easy to be damaged, suitable for various occasions. The fatal drawback is that water and dust on the screen surface can make the touch screen dull or even inoperable, making it hard to use.