The touch screen smart board can be divided into electromagnetic induction type, infrared induction type, pressure sensing type, ultrasonic induction type, and image sensing type. Each technology has different characteristics and advantages and has a certain share in the market. According to the analysis report of the international authoritative market research institute, in recent years, the electronic whiteboard using infrared sensing technology and electromagnetic induction technology has gradually occupied the dominant position in the market, accounting for more than 1/2 of the market share, followed by pressure and ultrasonic transmission technology, which accounts for about 1/6 of the market share. Foreign brands include Panasonic, Toshiba, and Plexus. Domestic famous brands include winger Dubord, Antarctica, Antarc, Honghe, and Julong. According to the hardware principle, it is divided into ultrasonic type, electromagnetic induction type, infrared type, and resistance type with the electromagnetic type electronic whiteboard slowly becoming the mainstream.
The basic principle of an optical touch screen smart board is similar to that of the projector, an infrared device is placed in front of the projected picture for receiving and transmitting infrared signals. It can be applied to 20-120 inch projection screens, with its size varying with the projection graphics. The projector can be used to operate the computer on the projected screen by projecting the projected image onto the screen or wall. As for the ultrasonic type, two ultrasonic receiving devices distributed at a fixed distance are placed on both sides of the screen. The pen used for positioning is an ultrasonic transmitter. When the pen moves on the surface of the screen, the emitted ultrasonic waves are detected by the receiver along the surface of the screen. By the time the ultrasonic wave is received, the distance between the pen and the two receivers can be converted. However, due to the bottleneck, it’s market share is not high.
The more popular type is electromagnetic induction touch screen smart board, which is based on Radiofrequency (RF) principle, with the sensor installed in the whiteboard core, and the specific frequency signal from the electromagnetic pen is received to achieve positioning. It has certain advantages like accurate positioning, high precision, and reliability, long life, fast response, pressure in the writing process, right-click support and other functions, which help achieve computer operation easily. It also has some setbacks like special pen must be used, the maintenance is complicated and difficult to operate, and the radiation to the human body is evident, which is not suitable especially for women and children for long-term use.
Others are infrared and CCD touch screen smart board versus resistance pressure sense type. The Infrared touch screen smart board is based on the principle that the object blocking the infrared light is detected by the infrared tube on the whiteboard while CCD touch screen smart board uses DVTT technology, also called CCD light scanning technology that sets CCD line array detector and infrared emitter with two fixed distances on one side of the display area, and reflective film that can reflect light on the other three sides while the CCD distributed in two corners detect the corresponding area of the occlusion area reaction line array CCD and calculates the position of the object in the display area, which is a cross-point test positioning method. Both technologies have advantages like accurate positioning, high precision, no need for special pen, long service life, fast response, simple maintenance, safety and environmental protection without radiation, and no disadvantages except for lack of pressure-sensitive response, which is a main trait of resistance pressure sense type that uses resistive film technology to realize pressure sensing positioning by detecting the resistance value. Its positioning is relatively accurate and no special pen is required. But it has setbacks like poor durability, fear of scratching, slow response, unable to do a large area, and its whiteboard pen does not support the right-click and other functions, making it difficult to operate the computer.
Resistance pressure sensing touch screen smart board can be further divided into wall-mounted, slide-type, mobile-type, and closet types according to the installation method. Among the above-mentioned touch screen smart board, CCD type has the simplest production process.