Security paper verification device

摘要

A photodiode and phototransistor are positioned on one side of a document subjected to verification for authenticity under both transmitted and reflected light. A corresponding photodiode and phototransistor on the opposite side of the document are arranged for receiving the light transmitted through the currency if the security feature is not present. A logic circuit determines the presence or absence of the security feature and correspondingly provides visual or audible indication thereof. The photodiodes, phototransistors and circuit are arranged within an enclosure that is attached to a currency receiving device such as a cash register. The visual or audible indicators are mounted on the cash register for immediate indication of the currency verification to the cashier.