摘要 |
An improved photoelectric sensor for an X-Y input device, the input device including vertical and horizontal slotted discs at ends of respective vertical and horizontal shafts, the discs being situated adjacent but not touching one another, is made up of a single photoelectric sensor and a single LED installed on opposite sides of the portions of the slotted discs that are adjacent each other, with the photosensor including four photoelectric sensor areas A, B, C, and D located on a single chip and having a width corresponding to the width of a slot or slotted wall of the slotted disc such that the rotation direction of the respective discs can be determined by whether the phase difference between signals generated by sensors A and B, and between signals generated by sensors C and D, is positive or negative.
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