触摸屏原理剖析.ppt

In-Cell触摸屏原理 2010.3.15 Introduction of touch panel 1. Resistive touch panel 1.1 traditional resistive touch panel (directly glue on LCD module) a. 4/5/6/8-wire resistive touch panel b. digital resistive touch panel (touch switches, matrix) 1.2 integrate resistive touch panel into LCD cell (between top and bottom glasses) 2. Capacitive touch panel 2.1 capacitance changed by deformation of top glass 2.2 capacitance changed by induced current from finger 2.2.1 surface capacitive touch panel 2.2.2 projective capacitive touch panel 2.2.2.1 detect self capacitance 2.2.2.2 detect mutual capacitance 3. Other touch panel (Infrared, SAW, Electromagnetic, Optical…) Resistive touch panel 1.1 4-wire resistive touch panel 1.1 4-wire resistive touch panel Low life time (around 1 million times) Low transmissivity (75%-85%) Not resist scratch Lowest cost Easy detect circuit Works with any stylus 1.2 Incell resistive touch panel—samsung(1) Basic principle: When pressed, the sensor switch is on (conductive column spacer contact sensor electrode) From plan view, at touch point, common electrode contact two sensing lines perpendicular with each other respectively 2. Capacitive touch panel 2.1 capacitance changed by deformation of top glass 2.2 capacitance changed by induced current from finger 2.2.1 surface capacitive touch panel 2.2.2 projective capacitive touch panel 2.2.2.1 detect self capacitance 2.2.2.2 detect mutual capacitance 2.1 Capacitive touch panel (压力式) This integrate type has some different structures, includes: Cell gap change type Samsung filed a patent (US20080048994). AUO has made a demo. LC alignment change type Samsung filed patent (US20050094038) very early, but Samsung’s demo applied another detect circuit (SID07 24.3), and Epson made a demo (SID08 55.2) based on Samsung’s structure by using LTPS, IPS and active matrix sensor so that improved the pe