Abstract: A coordinate system input device provides automatic calibration between coordinates detected and display coordinates and also provides a mouse function wherein movement of an object adjacent a display screen acts to move a displayed cursor an amount proportional to the movement of the object adjacent the display screen. In its automatic calibration function, the coordinate input device compares the coordinates of a displayed test cursor with the coordinates of a detected object adjacent the display screen and calculates a correction amount to correct subsequent detected coordinate positions. In its mouse function, the coordinate input device detects movement of an object adjacent the display screen and amplifies this movement to control a cursor displayed on the display screen. When the object is removed from the display screen, the procedure to be implemented, as indicated by the position of the cursor, is automatically initiated.

Abstract: An optical coordinate system input device includes a plurality of light emitting elements aligned in X and Y directions and sequentially, selectively supplied with a drive current, and a plurality of light receptor elements opposed to the respective light emitting elements each receiving a light signal from opposed one of the light emitting elements. The device specifically includes an adjusting circuit to adjust the value of the drive current flowing in the light emitting elements.

Abstract: An optical coordinate system input device including multiple opposed pairs of light emitting elements and light receptor elements which are sequentially selectively activated via a switching circuit, a variable impedance circuit connected in series with the light receptor elements to form a voltage divider, and an impedance detection circuit for detecting a low impedance of the light receptor elements caused by ambient light, wherein a detection signal from the impedance detection circuit lowers the impedance of the variable impedance circuit to increase the sensitivity of the input device to small changes in impedance of said light receptor elements upon detection of a light signal, emitted by said light emitting elements, by said light receptor elements in presence of strong ambient light.

Abstract: An optical path blockage detecting device includes optical conductive members located between light emitting elements and light receptor elements and extending parallel to optical paths defined between the light emitting and receptor elements. Each optical conductive member is combined with a light absorbing member which absorbs undesired beams of light so as to improve the optical directivity of incident light and improve the signal-to-noise ratio of the device.