| 摘要 |
<p>PURPOSE:To recognize the position of each operational switch by informing a user of the presence of a light shielding material at the time when this material is present thereon and the light shielding position is within the range of a preliminarily determined reference position. CONSTITUTION:Signals from phototransistors TRs 200 arranged in an X direction and those from photo TRs 220 arranged in a Y direction are analyzed to monitor the presence or the absence of a light shielding material; and if the presence of a light shielding material is detected by at least one of them and is detected in both of X and Y directions, the depressed switch is recognized in accordance with the intersection between positions of the light shielding material in respective directions, and corresponding processing is performed. If the presence of the light shielding material is detected by one of them, it is decided whether the detection position is the center or not, and a TR 302 is controlled to sound a speaker 308 when it is in the center. Consequently, the user recognizes the reference position of the screen, without seeing the screen.</p> |
