Abstract:
The present invention features a magnetic read head having an IC component provided within or adjacent to the head case. No low-level, analog signals, which are generally highly susceptible to electrical noise, leave the head structure. Power and ground signals are provided to the hybrid head. Digitized data corresponding to encoded information upon the magnetic stripe on a credit card, ID badge, or similar article is provided at output terminals. Decoding is performed by an ASIC or similar device located at the read head. A data strobe signal and/or a magnetic medium detected signal may also be provided by the read head.

Description:
This application is a continuation of Ser. No. 09/260,856 filed on Mar. 1, 1999 now abandoned. 
    
    
     FIELD OF THE INVENTION 
     This invention pertains to magnetic read heads adapted to read information from a magnetic stripe and, more particularly, to a magnetic read heads adapted with a fully integrated circuit (IC) component, the IC component being a mixed signal (analog and digital) circuit produced on a single silicon chip and being capable of converting the magnetic head signal into a digital signal for direct use by computer components. 
     BACKGROUND OF THE INVENTION 
     Magnetic read heads have been used for many years for such diverse applications as playing back music and/or video signals from a magnetic medium, such as a tape or stripe, reading magnetic characters on the bottom of checks, and reading magnetically encoded information from magnetic stripes on credit cards, telephone calling cards, access badges, tickets, and the like. Generally, the heads of the prior art feature a magnetic pole piece having a precision gap at or near the point of contact with the media to be read. One or more coils of wire wound around the magnetic pole piece generate a voltage in response to a change in a magnetic field near the head gap. The electrical signal induced in the head is then amplified, filtered and eventually decoded to retrieve the information from the magnetic medium. Heretofore, magnetic read heads have generally been stand-alone structures. Only the pole piece, housing and winding have been packaged as a single device. 
     U.S. Pat. No. 3,612,835 for COMBINED OPTICAL AND MAGNETIC TRANSDUCER, issued Oct. 12, 1971 to Boley A. Andrews, et al., teaches a magnetic read head with an optical transducer installed within the head assembly. ANDREWS, however, teaches no electronic circuitry. Both the magnetic and the optical transducers generate small-amplitude analog signals which are unmodified within the head structure. In contradistinction, the magnetic head of the present invention includes decode electronics so that no analog, small-amplitude signals leave the head assembly. Rather a decoded, digital signal is presented at the output terminals of the read assembly, or an attached cable assembly. 
     U.S. Pat. No. 5,276,572 for MAGNETIC DISK APPARATUS, issued Jan. 4, 1994 to Kinoshita et al., teaches an electric circuit for controlling a magnetic head, the circuit being mounted on a flexible printed circuit, folded within an enclosure. Thus, integrated circuit components have been used on circuit boards, separate from the head assembly, as taught by KINOSHITA et al. The circuits were not mounted to the read head, but to a movable arm on springs with the flexible printed circuit used to interconnect the heads with pre-amplifier circuits mounted to the movable arm. Additional circuits were mounted in a, fixed location below the movable arm. A considerable distance is present between the head and any circuits. 
     U.S. Pat. No. 5,117,097 for KEY SYSTEM FOR A VEHICLE, issued May 26, 1992 to Takashi Kimura, et al., teaches a tuned resonant circuit packaged within a key structure. While not a magnetic read head, the KIMURA structure does include a pole piece (i.e., the protruding extension of the key structure) having a winding thereupon. Discreet inductive and capacitive elements are connected to the winding to form a resonant circuit. The inventive read head, on the other hand, encompasses a structure to read information from a magnetic stripe or the like and, using self-contained circuitry, to provide a digital output signal corresponding to the information on the magnetic stripe. The inventive head does not rely on a resonant circuit comprising inductive and/or capacitive elements connected to the read head winding. 
     U.S. Pat. No. 5,212,602 for MAGNETIC HEAD HAVING A FUSE WITHIN HEAD CASE, issued May 18, 1998 to Hidefumi Suzuki teaches a magnetic head with a fuse physically within the head structure. The fuse is connected in series with the read head and is used to permanently disable the read head at end-of-life to prevent fraudulent use of the head (e.g., forging credit cards). The inventive read head, however, contains no fuse or similar structure designed to disable the head. Rather, the inventive head features an on-board decode electronics package designed to convert low-level, analog signals read from a magnetic stripe into a digital output signal. 
     Finally, U.S. Pat. No. 5,450,263 for THIN FILM INDUCTORS, INDUCTOR NETWORK AND INTEGRATION WITH OTHER PASSIVE AND ACTIVE DEVICES, issued Sep. 12, 1995 to Chan M. Desaigoudar, et al. teaches a fabrication technique for forming thin-film inductors, capacitors, resistors and semiconductors on a thin substrate. These components, used in combination, are capable of constructing a multi-channel, magneto-resistive or similar type read head. The magnetic read head of the instant invention, however, is totally different. A physical coil of wire wound upon a pole piece, not a thin-film inductor, is used as a traditional inductive pickup. Additional circuitry within or near the head casing is used not as a part of the pickup portion of the head, but rather as an IC component to convert a low-level, analog signal induced in the read head winding into a digital output signal. 
     It is therefore an object of the invention to provide a read head for reading encoded information from a magnetic stripe or similar magnetic medium. 
     It is a further object of the invention to provide a read head having IC components packaged within the head casing or packaged as a monolithic part of the head, forming a unitary structure. 
     It is an additional object of the invention to provide a read head adapted to receive power, ground and control signals and to provide a digital output signal at a standard, predetermined signal level. 
     It is a still further object of the invention to provide a read head which provides a magnetic media detected signal. 
     It is yet another object of the invention to provide a read head with a low susceptibility to external electrical noise. 
     It is another object of the invention to provide a read head with a case and flex circuitry or other such interconnection means, to supply power to the head, receive decoded signals from the head, or transmit digital signals to the head. 
     It is a still further object of the invention to provide a hybrid read head with IC components which has a higher reliability and lower cost than do magnetic read heads with external decode electronics. 
     SUMMARY OF THE INVENTION 
     The present invention features a magnetic read head having built-in electronic decode circuitry in the form of IC components. No low-level, analog signals, which are generally highly susceptible to electrical noise, leave the head structure. Power and ground are provided to the hybrid head. This invention combines the head element and, attached inside or directly on the immediate head structure, an IC together as a single structure, to form a single integrated reading component. This reading component is spring mounted as a single unit in the mechanical structure. Digitized data corresponding to encoded information upon a magnetic stripe on a credit card, I.D. badge, or similar article is provided at output terminals, attached cables, or other interconnections. In addition, a data strobe signal is provided by the head. An optional magnetic media detected signal may also be provided. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when taken in conjunction with the detailed description thereof and in which: 
     FIG. 1 is a cross-sectional, schematic drawing of a typical magnetic read head of the prior art; 
     FIG. 2 is a schematic block diagram of a typical magnetic stripe reading system of the prior art; 
     FIG. 3 is a schematic block diagram of the read head with IC components of the invention; 
     FIG. 4 a  is a schematic top view of an alternate embodiment of the read head with IC components wherein the IC components are mounted on a substrate attached to the back of a read head; 
     FIG. 4 b  is a schematic rear view the embodiment of the read head shown in FIG. 4 a;    
     FIG. 5 is a schematic view of the read head and IC components shown in FIG.  4  and also showing an attached cable and connector; and 
     FIG. 6 is a schematic view of a third embodiment of the read head with IC components wherein the IC components are mounted on a substrate integrally attached to a flexible circuit assembly. 
    
    
     The same or similar reference numerals are used throughout the drawings to depict like components. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Generally speaking, this invention relates to a magnetic read head for use in recovering encoded information from the magnetic stripe on a credit card or similar article. More specifically, there is disclosed a magnetic read head having IC components which provide a digital signal output. This invention combines the head element and, attached inside or directly on the immediate head structure, an IC together as a single structure, to form a single integrated reading component. This reading component is spring mounted as a single unit in the mechanical structure. 
     Referring first to FIG. 1, there is shown generally at reference number  10 , a cross-sectional view of a typical magnetic read head. A core  12  is constructed from a high-permeability material such as mumetal or ferrite. Ferrite cores  12  are generally solid pieces of material while those constructed from steel or mumetal are often laminated to reduce eddy currents in the core  12  structure. Core  12  is discontinuous at an apex region  16 . A winding coil  14  is wrapped around core  12  such that magnetic flux (not shown) in core  12  induces a voltage in the winding  14  which terminates at external connectors  24 . An optional shim  18  may be placed in the gap in core  12  at apex region  16 . Core  12 , winding  14  and optional shim  18  are all enclosed in a common housing  20 . A potting material  22  may be used to fill the space in housing  20  not occupied by the head components, thereby securing the components. Housing  20  is generally constructed from a high permeability material which provides magnetic shielding to the coil  14  of head assembly  10 . 
     Referring now to FIG. 2, there is shown a simplified, schematic block diagram of a typical magnetic read head  10  of the prior art shown “reading” information from a magnetically-encoded article  28 . The article  28  comprises a plastic substrate  30  with a magnetic stripe  32  disposed thereupon. This is a construction typically used for credit cards, ID badges, hotel keys, and many other applications and structures well known to those skilled in the art. 
     When article  28  is moved past read head  10  as shown by arrow  34 , magnetic information (not shown) previously encoded onto magnetic stripe  32  induces a small voltage into winding  14  of head  10 . This voltage is coupled to an amplifier  36  along a wire or cable  38 . Cable  38  generally has a shield  40  connected to ground  42 . Shield  40  is designed to protect the small voltage generated by head  10  from interference by electromagnetic fields (not shown) in the region of cable  38 . 
     Amplifier  36  is generally provided with a differential input to help minimize common-mode interference. Other strategies and/or amplifier configurations are well known to those skilled in the circuit design art. An output signal from amplifier  36  is provided to a decode circuit in the form of one or more IC components (hereinafter referred to as “an IC component”)  44 ′ where the amplified, analog signal from head  10  is converted to a digital signal at a standard voltage. Decode circuitry suitable for use in the application of magnetic stripe reading is well known in the art, as is exemplified, for example, in U.S. Pat. No. 5,240,523 for DECODING FOR MAGNETIC STRIPE RECORDING, issued to George R. Steele. 
     Referring now to FIG. 3, there is shown a simplified schematic block diagram of the magnetic read head  50  of the present invention shown “reading” information from a magnetically-encoded article  28 . As in the prior art, when article  28  is moved past read head  50  as shown by arrow  34 , magnetic information (not shown) previously encoded onto magnetic stripe  32  induces a small voltage into winding  141  wound on core  12 ′ of read head  50 . The low-voltage, analog output signal from core  14 ′ no longer must leave the read head  10  (FIG. 2) and be subjected to electromagnetic fields, as in the prior art. The output signal  15  is directly coupled to the input of amplifier  36 ′ proximate winding  14 ′. Because winding  14 ′ and amplifier  36 ′ are located close together, completely within shielding housing  20 ′, the small, analog signals are no longer exposed to extraneous electromagnetic interference. Design parameters for amplifier  36 ′ may possibly be less demanding than for amplifier  36  (FIG. 2) of the prior art. 
     An output signal  38  from amplifier  36 ′ is provided to the input of IC component  44 ′. Since magnetic heads comprise one or two or three read elements, one IC component  44 ′ is required for each read element. The amplified, analog signal  38  from winding  14 ′ is converted to a digital output signal  40  at a standard voltage. IC component  44 ′ may be implemented using application-specific integrated circuits (ASICs) or a general-purpose microprocessor in combination with programmable array logic devices, (PALs) or other gate array devices as are well known to those skilled in the art. Other ancillary passive components (not shown) such as decoupling capacitors or the like may also be provided. The output signal  40  is provided at output connections  52 . 
     Voltage and ground signals are provided to hybrid head  50  at terminals  54  and  56 , respectively. In addition, a read strobe signal is provided by IC component  44 ′ via output connector  58 . An optional magnetic medium detected output signal  46  generated by IC component  44 ′ may be provided at connector  60  on head  50 . The magnetic medium detected output signal  46  may be used by external equipment attached to the read head but is not a part of the instant invention. 
     The inclusion of amplifier  36 ′ and IC component  44 ′ at the head  20 ′ provides several important advantages. First, the inclusion of the IC component  44 ′ close to the coil  14 ′ of the read head  10  itself essentially eliminates the exposure of the low-level, analog signal  15  from the head  10  to extraneous electro-magnetic fields. This allows for simplification particularly of the amplification circuitry. Because low level, external connections are eliminated, the overall reliability of the head/amplifier/decode system is improved. These read/amplify/decode functions can also be performed with a device costing substantially less than do the individual components of the prior art. 
     Referring now to FIGS. 4 a  and  4   b , there are shown, generally at reference numeral  60 , schematic top and rear views, respectively, of a read head assembly with IC components mounted on a substrate  62  attached to the back of a read head  10 . Substrate  62  is configured to hold and interconnect a variety of electronic components, typically one or more ASICs  64 , along with miscellaneous support circuitry (not shown). Substrate  62  may be attached to head  10  in a variety of ways well known to those skilled in the art. An optional protective coating  67  may be placed over the assembly of head  10  and substrate  62  when required. This coating may be a potting or other suitable material. Substrate  62  is shown mounted to the rear surface of head  10 . It should be obvious that substrate  62  may be attached to other surfaces of head  10  when required by a particular operating environment. 
     Referring now to FIG. 5, there is shown a schematic view of the head/substrate assembly  60  with an attached cable  66 . Cable  66  provides power to the circuitry on substrate  62  and also carries digital signals to and from the circuitry. One end of cable  66  may be permanently attached to substrate  62  or, in alternate embodiments, attached to substrate  62  by means of an optional connecter (not shown). The other end of cable  66  terminates in a connector  68  adapted to plug into a socket (not shown) 
     Referring now to FIG. 6, there is shown a schematic view of another alternate embodiment of the read head with IC components. The function of substrate  62  (FIG. 4) has been replaced by flexible circuit assembly  70 . One end  72  of flexible circuit  70  has been widened to accommodate ASICs  64  and other ancillary circuitry (not shown) and is attached to head  10 . Conductors in flexible circuit  70  replace the function of cable  66  (FIG.  5 ). The distal end  74  of flexible circuit  70  is formed into a connector adapted to mate with an external socket (not shown). The use of a flexible circuit assembly  70  improves the overall reliability at a lower component cost than that of the embodiment of FIGS. 4 a ,  4   b  and  5 . 
     Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention. 
     Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims.