| 摘要 |
<p>The invention relates to a contact display panel circuitry in which the phototransistors (1) are on two adjacent sides of the contact display panel and the diodes emitting infrared radiation to the phototransistors are on the opposite sides, and in which, under the control of transfer registers, each phototransistors (1) in turn is coupled to a common line (c), the logic circuit of the device being capable of computing the location of a possible contact point on the basis of changes in the signal in the common line (c). According to the invention the use of controllable switches and numerous resistors and capacities is avoided by coupling in series with the phototransistor (1) a diode (2) in such a manner that the collector of the phototransistor is coupled to the transfer register and the emitter is coupled via the said diode (2) to the common line (c).</p> |
