The present disclosure relates to a use of a piezo-based switch in an active card. the content of which is incorporated herein by reference in its entirety.
Active cards, such as an active credit card or debit card, include one or more of an embedded microprocessor and a display unit, which provide intelligent capabilities to the card. For example, a user can tap an active credit card or press a button on the active credit card to activate one or more functionalities of the active card. As such, an active card requires a robust switch mechanism for both on/off and function capabilities.
In the following description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, electrical, and optical changes may be made without departing from the scope of the present invention. The following description of example embodiments is, therefore, not to be taken in a limited sense, and the scope of the present invention is defined by the appended claims.
In an embodiment, piezoelectric film sensors form the basis of a viable circuit that can be used to activate functions in a non-contact manner in an active card module such as a smart card. The circuit or switch can be used for activation, deactivation, or other additional functionalities in the embedded circuit of the active card. The piezoelectric film sensor is comprised of a thin film sensor element that outputs voltage in response to a dynamic strain. Consequently, if the active card is bent or tapped in a known manner, the piezoelectric switch outputs a voltage that can be used to trigger a circuit embedded in the active card to execute a specific operation.
In an embodiment, the piezoelectric film is covered by a thin insulating film coating, with only contact leads exposed. The thin insulating film coating can be a urethane coating. The piezoelectric film can be shielded inside a foil membrane. In one example embodiment, the piezoelectric film sensor is positioned between the embedded circuit's ground plate and a lithium polymer battery. This construct shields against noise sources that can trigger the device inadvertently.
The piezoelectric film sensor circuit should be designed so as to avoid unintentionally triggering the circuit, for example, if the card is dropped. As one of skill in the art will appreciate, precise values of circuit components depend on the capacitive value of the piezoelectric film membrane and the desired ease or difficulty in triggering the circuit.
The circuit 100 in
The circuit 100 of the active card 50 functions as follows. The piezoelectric film sensor 110 receives an input stimulation, which causes the piezoelectric film sensor 110 to output a voltage in response to the input stimulation. The input stimulation can be such things as a tapping of the active card or a bending of the active card, thereby inducing a dynamic strain in the piezoelectric film and the generation of a voltage. The active card module 160 receives the voltage generated by the piezoelectric film sensor 110, and the active card module 160 executes a function in response to the received voltage. The function executed by the active card module 160 can include such things as activation of the embedded circuit, a deactivation of the embedded circuit, or an addition of a function to the embedded circuit. As noted, a battery 150 is coupled to the active card module 160. A ground plane (not illustrated in
It should be understood that there exist implementations of other variations and modifications of the invention and its various aspects, as may be readily apparent, for example, to those of ordinary skill in the art, and that the invention is not limited by specific embodiments described herein. Features and embodiments described above may be combined with each other in different combinations. It is therefore contemplated to cover any and all modifications, variations, combinations or equivalents that fall within the scope of the present invention.
The Abstract is provided to comply with 37 C.F.R. ยง1.72(b) and will allow the reader to quickly ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
In the foregoing description of the embodiments, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting that the claimed embodiments have more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Description of the Embodiments, with each claim standing on its own as a separate example embodiment.
The present application claims priority to U.S. Serial Application No. 61/694,102, the content of which is incorporated herein by reference in its entirety.
The present invention was made with support from the United States government under contract number ****-***9825-***. The United States government has certain rights in this invention.
Number | Date | Country | |
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61694102 | Aug 2012 | US |