whiteboard js., Affected by temperature, 3 , needs special pen using this technology the major manufacturers of the HITACHI , IBEAM other five: CCD optical scanning CCD optical scanning principle: two side disposed a fixed distance in the display area CCD linear array detector And the infrared emitter, aligned with the display area. A reflective film that reflects light is disposed on the other three sides of the display area, and when there is no object blocking, the line CCD detects a complete light band. When an object blocking the light propagation path in the display area, line array CCD detected light band appears in the non-reflective region, the distribution of angles in two CCD detect the occlusion regions reaction Linear Array CCD corresponding to the region, in accordance with The corresponding area calculates the position of the object in the display area, which is a cross-point test positioning method. This technology is a relatively new technology, not fully mature, and its biggest advantage is that it can do multiple simultaneous touches. In addition to a few manufacturers in trial use, it is also fully popular, and there is not much information available. In summary, the interactive whiteboard uses different positioning methods, which will have different characteristics and performance. The following table summarizes and contrasts the above texts. I believe that readers can distinguish the differences between various technologies and choose a product that suits them.