Coordinate input / detection device, electronic blackboard system, position shift correction method and storage medium of the light-receiving element

摘要

PROBLEM TO BE SOLVED: To prevent the generation of the erroneous detection of position coordinates into which an instructing means is inserted due to the deviation of the mounting position (angle) of a light receiving element.;SOLUTION: The waveform of a light reception signal corresponding to the intensity distribution of lights received by a light receiving element in a prescribed timing is compared with a reference waveform, and when it is judged that the waveform is not coincided with the reference waveform (Y of S9), it is judged that position deviation is generated in the light receiving element due to vibration or impact. Then, a reference waveform storing means (S2) is again carried out so that at a new reference waveform can be stored in a waveform storage part. Thus, the waveform of the light reception signal corresponding to the intensity distribution of the lights received by the light receiving element in which the position deviation is generated is defined as the reference waveform so that any deviation can be prevented from being generated in a position relation between the peak point of the intensity distribution of the lights generated by a reference mark being the reference of position coordinate detection in a coordinate detecting means (S7) and the peak point of the intensity distribution of lights corresponding to an instructing means inserted into a coordinate inputting/detecting area. Thus, it is possible to prevent the generation of the erroneous detection of the position coordinates into which the instructing means is inserted.;COPYRIGHT: (C)2001,JPO