Regarding multi-touch, both the projected capacitive type and the optical type support this function. In addition, in resistive and surface acoustic wave types, which have been difficult to achieve multi-touch, technologies have also emerged to support this function. In terms of resistance, Stantum of France has adopted digital and matrix technology to develop a resistive touch screen that supports input of more than 10 points. In terms of surface acoustic wave, Touch Panel Systems has commercialized a surface acoustic wave touch screen that supports 2-point touch.
According to the characteristics of various touch screens, they can be used in different products. For example, portable game consoles and electronic notebooks that use handwriting input use resistive type, portable terminals that support multi-touch use capacitive type, and ticket sales using about 20ine screens. Computers and personal computers use optical types, and public information terminals that require durability, large screens and high resolution, use surface acoustic wave types, etc.
However, the above-mentioned methods have advanced at an amazing speed, and gradually realized the characteristics that were impossible to achieve a few years ago. Not sticking to the "common sense" of the past, keeping abreast of the latest technological progress and development trends will be the key to flexible use of touch screens. From the perspective of technical principles, the touch screen is a set of transparent absolute positioning system, which has the following characteristics:
1) It must be transparent. The touch detection device is on the top of the display screen. First of all, it must be transparent. Therefore, the transparency problem of the material must be solved. Therefore, its light transmittance and its anti-glare and anti-reflection characteristics are also relatively important. At present, the best light-transmitting material is glass, but when light passes through, the two surfaces of the glass will reflect 3 percent of the light respectively, that is, the maximum light transmittance of single-layer glass is 94 percent , which makes the light reaching the human eye Suffered a loss.
It is not easy for capacitive touch screens to achieve high light transmission and anti-glare. Generally, the light transmittance is only 85 percent , and the anti-glare effect is not good. But the light transmittance of the new generation capacitive touch screen is 91.5 percent , with anti-glare and anti-reflection treatment on its surface. Compared with resistive touch screens, capacitive touch screens brighten the entire vision and improve the overall visual texture a lot. The manufacturers of touch screens do not have to modify the display to increase the brightness, which saves a lot of costs.
2) Absolute coordinates, wherever the finger is touched, no need for the second action. Unlike a mouse, it is a relative positioning system. The touch screen does not require a cursor. Cursors affect the user's attention. The cursor is used for relative positioning devices. To move a relative positioning device to a place, you must first know where you are now. Which direction to go, you still need to constantly feedback the current position to the user at all times so that there will be no deviation. These are not required for touch screens that adopt absolute coordinate positioning. The second is the ability to detect finger touches and determine the position of the finger. Various touch screen technologies are developed around detecting finger touches.
As a human-computer interaction interface, the touch screen does not have a real operating feel, and cannot respond to pressing actions like a real keyboard. This is the biggest problem that plagues equipment manufacturers now, how to solve the problem that the touch screen does not have a real operating feel. Various equipment manufacturers are doing corresponding explorations. Motorola has added a vibration function to the touch operation of the V8 flip phone as a feedback for the successful operation of the user. Apple has implemented force feedback by improving the physical structure of the screen on the Apple computer. After maturity, it will also be applied on mobile phones or MP3 devices.
