What are the categories of multitouch screens

- Jul 17, 2018 -

What are the categories of multitouch screens?Projected capacitive touch screen is still predominantly capacitive sensing, surface capacitive touch screens, but compared with projected capacitive touch screen USES multiple ITO layer, form the matrix distribution, on the X axis and Y axis crossing distribution as capacitance matrix, when a finger touch screen, through the X, Y axis scanning, detect the touch location of capacitance, and then calculate the position of the finger contact.Based on this architecture, the projection capacitance can achieve multi-touch operation.There are two types of capacitance on the projection capacitive touch screen: self-capacitance and interactive capacitance.Self-capacitance, also known as absolute capacitance, is a widely used method.It is the feeling of objects as another plate capacitance between the object in the sensing electrode and the sensing electrode induction electric charge, so as to be felt and measuring the charge stored in the capacitance coupling.Based on multi-touch technology of capacitive touch screen to realize human-computer interaction research is multi-touch recognition signal direction, is the only detect and distinguish multi-touch behavior, such as scaling, drag, rotate, etc., is implemented as the axis staggered type technology.It is a diamond shaped sensing unit planning on the conductive layer, and one conductive layer is required for each axial direction.Two axis type, for example, when detect touch behavior, sensor controller will scan horizontal axis and vertical axis respectively, produce capacitor stick close feeling of horizontal, vertical, there will be a rising wave of measuring points and the intersection of two axis is touch point.Although axial cross can realize the recognition function of multi-touch gesture, it is still difficult to locate the correct position of multiple contacts.Because in the two axial scanning, two touch points respectively in the X axis and Y axis each have two peaks, up to four contact, the two points is a pseudo touch points, this will make the system to correct interpretation.