PURPOSE: To prevent the interference fringes of light produced at handwriting input by providing a gap of a prescribed space between the input screen of a coordinate input device and the display screen of a display device.

CONSTITUTION: A gap of a prescribed space that is decided by the size, the thickness, the material of an input screen 15 of a coordinate input device is provided between the screen 15 and a display screen 11 of a display device. For instance, the screen 15 is provided on the screen 11 with intervention of a spacer 13 which functions to secure a gap larger than the fixed value between both screens 11 and 15. Then the space 13 can use an adhesive material like a two-sided tape, etc. Thus the generation of interference fringes of light are evaded at the time of inputting by handwriting even with the warp of the screen 15.