4. Touch Switch InputsThe keys on the touch panel and the control panel controller PCB are connected asshown in Figure 7-102.The touch switch panel consists of a sheet of glass having a transparent conductingmembrane and a sheet of film with spacers in between; it shows a pattern consisting of15 rows and 20 columns.When its surface is pressed with a finger, contact between the glass and the filmcauses electrical continuity, thereby connecting a pair of electrodes so that the corre-sponding X/Y coordinates are obtained as in the case of a common key matrix.In other words, the correspondence between key scan signals from the control panelcontroller circuit and the input signals to the control panel controller circuit enables thecontrol panel controller PCB to identify which key has been pressed.Figure 7-104ElectrodeElectrode SpacerGlass sheetFilmCHAPTER 7 EXTERNALS/AUXILIARY MECHANISMS7-5COPYRIGHT © 1997 CANON INC. CANON NP6560/NP6360/NP6260 REV. 0 NOV. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
