Memory device

A credit control system comprising:

• (a) a portable credit device including a display, said display including a plurality of respective segments arranged in a pattern, each of said segments including:
• an electrochromic cell containing a solid electrolyte and a transition metal oxide which can colour cathodically by reduction or anodically by oxidation to store readable information, and electrical connecting means for applying an electrical signal of a first polarity to said cell to produce a visible persistent colour in said cell, said colour remaining visible in the absence of the said signal, for applying an electrical signal of a second polarity different from said first polarity to said cell to change the color of said cell, and for electrically connecting the standing voltage of said cell to a reader unit,
• (b) a reader unit for electrically reading and transmitting information carried by the portable credit device,
• (c) a processor for receiving the transmitted information from the reader unit, processing information received (optionally in conjunction with information available to the processor) and transmitting information resulting from the processing to
• (d) a transcriber unit which can receive the transmitted information and correspondingly amend at least some of the information stored by the portable credit device.

A process for the credit purchase of goods comprising:

• (a) issuing to a customer in exchange for one of cash and credit a portable credit device including a display, said display including a plurality of respective segments arranged in a pattern, each of said segments including:
• an electrochromic cell containing a solid electrolyte and a transition metal oxide which can colour cathodically by reduction or anodically by oxidation to store readable information, and electrical connecting means for applying an electrical signal of a first polarity to said call to produce a visible persistent colour in said cell, said colour remaining visible in the absence of the said signal, for applying an electrical signal of a second polarity different from said first polarity to said cell to change the color of said cell, and for electrically connecting to the standing voltage produced by said cell, wherein the information stored in said plurality of segments represents a value,
• (b) accepting said device from the customer at a point of transaction,
• (c) reading the information stored in said segments by sensing the standing voltages, produced by said cells and connected to the electrical connecting means of said segments,
• (d) transmitting the information read by said reading step (c),
• (e) receiving the information transmitted by said transmitting step (d), processing information received (optionally in conjunction with information available to the processor) and transmitting information resulting from the processing,
• (f) receiving the information transmitted by said transmitting step (e),
• (g) reducing the value represented by the information stored by said device in response to said received processed information by an amount equal to the value of goods purchased by the customer, and
• (h) returning the said device to the customer.

A credit control system comprising:

• a portable credit device including:
• display means for storing visual indicia of credit, said display means including a plurality of respective electrochromic cell means for selectively changing between a first and a second visually discernable state in response to electrical signals, said state change persisting after said electrical signals are removed, and
• a plurality of respective electrical conductor means, electrically connected to said cell means, for conducting electrical signals;
• transcribing means, adapted to electrically connect to said plurality of electrically conductor means, for selectively applying electrical signals through said plurality of electrically conductor means to said plurality of electrochromic cell means to store said indicia;
• and
• reader means for sensing the state of each of said plurality of electrochromic cell means to ascertain said stored indicia.

A process for the credit purchase of goods comprising the steps of:

• issuing to a customer, in exchange for monetary consideration, a portable credit device including:
• display means for storing visual indicia of said monetary consideration, said display means including a plurality of respective electrochromic cell means for selectively changing between a first and a second visual state in response to electrical signals, said state change persisting after said electrical signals are removed;
• and
• a plurality of respective electrical conductor means for conducting respective electrical signals to said plurality of electrochromic cell means to change the state of said plurality of cell means and for conducting a standing voltage produced by each of said cell means indicating the state of said each to electrically ascertain said indicia, said indicia representative of the value of said consideration;
• accepting said device from the customer at a point of transaction;
• ascertaining said stored indicia by sensing the state of each of said plurality of electrochromic cell means;
• subtracting, from said stored indicia, the value of goods purchased by the customer by selectively applying signals through said plurality of electrical conductor means to said plurality of electrochromic cell means;
• and
• returning said device to the customer.