Instrumented Token

Abstract

Disclosed is an instrumented token or chip representative of value. Concealed within or on the surface of the token is a passive resonant circuit which responds to incident electromagnetic radiation in a preselected frequency to produce and radiate a unique detectable signal indicative of the token's presence in the incident field.

Description

BACKGROUND OF THE INVENTION

As soon as man developed a monetary system involving token or device of relatively light weight to be used in exchange for goods and services, two problems emerged and have remained with us to this very day. These problems are one, that of counterfeiting by those who would skillfully make replicas of the genuine currency and the second problem is that of theft. Coins, another currency being of the nature light in weight easily concealed, are readily subject to theft and thereafter because of their near identical shape and size are not identifiable as to source.

Characteristically, these two problems are solved by independent means. Counterfeiting is minimized by including in the currency certain difficult to produce features, such as precise steel die engraving or use of particular papers or materials, the supply of which is controlled.

Automatic sensing systems have been developed for detecting counterfeit currency which operate through the measurement of physical properties, such as weight, size, magnetic properties and the like of coins and through pattern matching in the case of paper currency.

The prevention of theft of money has been thwarted by physical security means, constant inventory and certain cases, personal searches.

Characteristically, nearly all of the counterfeit detection and theft protection systems require complete physical control or contact with the currency. In some cases, it is difficult or impossible to achieve, so maximum protection against both of these problems is not available. In certain cases radioactive tracers or magnetic particles have been embedded in objects to facilitate their detection or discrimination from counterfeits, however magnetic traces are easily duplicated and radioactive traces are expensive and particularly require sensitive expensive detection equipment.

BRIEF STATEMENT OF THE INVENTION

In the use of tokens, chips and other devices, representative of money, merchandise or services, a greater degree of freedom is afforded the producer as compared with currency. This freedom may take the form of size, shape, materials, color, but when such a standard is once established, it normally must be maintained without change.

We have invented a system for both detecting counterfeit tokens or chips and segregating from valid ones, and at the same time detect the presence of genuine tokens or chips in areas where such articles are unauthorized, for example in the pocket of a departing employee.

We have invented such a system which does not change the internal characteristics of the token or chip and to all intents of purposes is identical with noninstrumented devices.

We have developed such a chip which is electronically detectable and therefore may be distinguished from inert counterfeit chips. The chips in accordance with this invention are detectable remotely without physical contact. Also the chips are passive insofar as requiring any power supply or consumable materials. This invention comprises basically a dielectric body with an inductive loop imbedded therein and terminating in a capacitance element. The loop and capacitance element constitutes a resonant circuit which responds to a selected frequency to constitute a repeater oscillator producing a detectable signal.

BRIEF DESCRIPTION OF THE DRAWING

This invention may be more clearly understood from the following detailed description and by reference to the drawing in which:

FIG. 1 is a perspective view of a chip or token in accordance with this invention;

FIG. 2 is a transverse section through the chip of FIG. 1 along the line 2--2 of FIG. 1;

FIG. 3 is a diametrical section through the chip of FIG. 1 along the line 3--3 of FIG. 1;

FIG. 3a is an enlarged fragmentary section of the view of FIG. 3;

FIG. 4 is a simplified block diagram of a system for detecting chips in accordance with this invention;

FIG. 5 is a graphical representation of the resonant characteristics of the chip of this invention;

FIG. 6 is the electrical schematic of the chip of this invention.

FIG. 7 is a front elevational view partly in section of a tag incorporating this invention; and

FIG. 8 is a front elevational view of a piece of paper currency incorporating this invention.

DETAILED DESCRIPTION OF THE INVENTION

Now referring to FIG. 1, the external appearance of a token incorporating this invention may be seen. For purposes of illustration it is shown as a chip 10 of a type commonly associated with games of chance. However, the token may be of different shape and used for different purposes and may be of the type which is individually designed for the particular needs. Employing the basic concept of this invention, the token or chip may also be merely paper or cardboard with the invention actually printed thereon either visibly or imbeded in the surface to provide security. Suffice it to say the token or chip employed in this invention constitutes basically a dielectric body generally planar shape. In this case, it is shown as a circular flat disk chip 10 approximately 1 1/2 inches in diameter and having an edge thickness in the order of 1/8th inch. Its composition is normally that of a molded plastic either with or without inert fillers. In any case, it exhibits dielectric properties.

Given the token or chip 10 of the above dimensions, and having a weight in the order of 9 to 10 grams, the device is easily transported in the pockets, crevices of clothing without being visible making them easily stolen. As shown in FIG. 1 the token or chip appears to be substantially identical with a chip not incorporated in this invention. Also, as will be described below the weight of the addition to the chip of this invention is substantially equal to the materials displaced so that there is virtually no detectable difference in weight from an unmodified chip.

The only change in the chip 10 is best illustrated in FIG. 2 which is a transverse section through the chip 10 of FIG. 1. It may be seen that imbedded in the periphery of the chip is a wire 11 which extends around in a loop and terminates in an element to which the ends of the wire are electrically connected. This element is a capacitor 12 which visibly constitutes the closure of the ring and electrically constitutes the capacitance element which cooperates with the inductance of the loop to provide a resonant electrical circuit. The equivalent circuit shown below in FIG. 6 and employing copper wire as the loop and a capacitance of the type which has an extremely low resistance. The resonant circuit exhibits an extremely high Q in the order of 50 or more.

The minimum size and relative positioning of the resonant circuit of this invention is apparent in FIG. 3 which is a diametrical section through the chip 10. The circuit appears only as a fine wire 11 embedded in the periphery and a metallic like bar, capacitor 12, of minimum cross section also located in the periphery of the disk or token 10. The minimum size of the resonant circuit results in minimum weight change in the chip. Through the selection of the encapsulating material 13, best seen in FIG. 3a, the weight can be compensated to avoid any change in weight from the unmodified chip. The edge encapsulating material 13 may be identical with that of the body of the chip and the resonant circuit actually molded in place. However, we have found that to avoid the temperatures and pressures of the molding operation that it is desireable to take a completed molded chip, mill an edge groove, insert a wire in the groove, bond it as by soldering to the capacitance element and then seal the entire edge with a material such as epoxy resin. The resin without filler is slightly lighter weight than the normal filled disk and the weight compensation measurement is thereby achieved.

In the completed chip it is apparent that these copper and magnetic materials are used in the resonant circuit so that the chip does not exhibit any ferro magnetic properties nor does it emit any particles of radiation. Therefore, by simple testing with a magnet or through radiation sensitive devices, the chip is not detectable from normal unmodified chips.

The parameters of the resonant circuit of this invention may be varied depending upon the size and shape of the token to be instrumented. We have found that the following components and characteristics are preferred for a conventional playing chip.

Wire 11 1 1 turn of No.18 copper wire Capacitor 12 Type, ceramic chip manufactured by U.S. Capacitor Corporation Burbank, California Capacitance: 10pfd - 300 pfd

11 and 12 as a resonant circuit Resonant frequency: 26 - 160 MHZ Q: 70 - 100

the use of this invention is illustrated in FIG. 4 which is the system shown in its simplest form. It involves a device including a signal generator 20 and a radiating antenna 21 represented simply as a box and a horn which are tuned at a preselected frequency or narrow band of frequencies in which the resonant frequency of the chip 10 falls. In spaced facing relationship to the transmitter 20 is a receiving antenna 22 and a receiver 23 also tuned to the same frequency or range of frequencies. The receiver 23 initially includes a detector of the type illustrated in our copending application Ser. No. 272,831 filed July 18, 1972, which responds to ringing or sustained oscillation detected by receiver 23.

FIG. 5 represents the frequency admittance characteristics of the resonant circuit of this invention. The curve reflects a typical resonant peak at the selected operating frequency of the system. The narrow tall resonant peak illustrates the high Q of the circuit enhancing response to incident electromagnetic radiation. The resonant frequency of course is selected consistent with the dimensional limitations of the token 10 and practical operating frequencies for the remainder of the system of FIG. 4.

The equivalent circuit of the resonant circuit of this invention including the loop 11 illustrated as an inductance and capacitor 12. Resistance of the loop 11, capacitor 12 and junctions therebetween are illustrated as lumped resistance 14. Resistance 14 is preferably low to maintain a high Q.

Given the foregoing parameters for the resonant circuit of this invention it is possible to incorporate the same in other forms of tokens or devices. Another form of particular significance is a tag of the type commonly used in retail establishments attached to merchandise prior to sale. Such a tag 30 appears in FIG. 7. It is a multiple part tag particularly useful for inventory control. It includes a cord or fastening device 31 of some type or may simply be affixed to merchandise by an adhesive. The tag 30 includes one or more lines of perforations 32 dividing the tag into at least two parts, one part 33 which is removed by the sales person at the time of sale and the remaining part 34 which remains affixed to the article until removed by the purchaser after arriving home.

The tag 30 is shown in partial section illustrating that it is multilayered having an upper layer 35 upon which sales indicia is imprinted, a second layer 36 upon which the resonant circuit is deposited or printed and a third or outer layer 37 which acts as a backing for the tag. The layers 35-37 are thin so that the tag 30 exhibits no additional thickness than a conventional sales tag. Suffice it to say the layers 35-37 are of dielectric material such as paper providing a suitable body for supporting the resonant circuit made up of loop 40 and capacitance 41 in the tag section 33.

Employing this invention, any attempt to pass the entire tag through the system of FIG. 4 will result in the detection of the presence of the resonant circuit of this invention.

Another form of this invention is illustrated in FIG. 8. It comprises a piece of currency or similar paper 50 or the like of paper having indicia printed on the surface. As a part of the indicia the loop 51 and capacitor 52 of this invention are an unobtrusive part of the indicia. The detection of the presence of currency 50 and its segregation from counterfeits is accomplished again employing the system of FIG. 4.

The foregoing is a brief discussion of the operation of the system and for more details the reference should be made to the copending application identified above.

The above described embodiments of this invention are merely descriptive of its principles and are not to be considered limiting. The scope of this invention instead shall be determined from the scope of the following claims, including their equivalents.

Claims

What is claimed is:

1. An instrumented token comprising a body of dielectric material;

passive circuit means embedded within said body;

said passive circuit means comprising at least one turn of conductive material with the ends in juxtaposed spaced end on relation with each other and constituting an inductive element;

a discrete capacitance element electrically connected to and closing the gap between the ends of said turn of conductive material;

said passive circuit means comprising a resonant circuit responsive to incident electromagnetic radiation for producing a detectable change in such electromagnetic radiation outside of said body wherein said body of dielectric material comprises a disc with said passive circuit means embedded in the periphery thereof.

2. The combination in accordance with claim 1 wherein said passive circuit has a Q of at least 50.

3. The combination in accordance with claim 2 wherein said passive circuit has a Q of between 70 and 100.

4. The combination in accordance with claim 1 wherein said chip like body includes an edge groove and said passive circuit is positioned in said edge groove and is sealed therein.