Metal fingerprint authentication card

Abstract

To provide a metallic fingerprint authentication card advantageous to acquire a fingerprint pattern in common mode noise and different electric characteristics of fingers, and having a circuit configuration inside a film-like substrate including an ESD protection circuit configuration.SOLUTION: In a metallic fingerprint authentication card, a film-like substrate and a magnetic sheet laminated on the film-like substrate are integrated by sandwiching and laminating the film-like substrate and the magnetic sheet with front and rear card base materials. In the metallic fingerprint authentication card, an external connection terminal, an active capacitance type fingerprint sensor, a wiring pattern, a loop antenna circuit for performing non-contact type communication, an IC module, and a ground pattern are mounted on the film-like substrate, the film-like substrate is provided with a U-shaped type slit so as to surround the ground pattern, and U-shaped type slits having opposite directions overlapping a U-shaped region of the film-like substrate are provided on the magnetic sheet.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a metal fingerprint authentication card used for credit cards, debit cards, cash cards, access control cards, and the like.

Background Art

[0002] In recent years, fingerprint authentication devices such as fingerprint authentication smart cards have begun to spread. Examples of fingerprint authentication smart cards include credit cards and access cards. The fingerprint authentication methods are roughly classified into three types: "capacitive", "optical", and "ultrasonic". Currently, the mainstream fingerprint authentication method is the "capacitive" method.

[0003] A passive capacitive fingerprint sensor measures the capacitance that changes according to the distance between the surface of a finger in contact with a conductive structure arranged near the sensor array and a sensing structure arranged in the sensor array to detect a fingerprint pattern. When passively reading the capacitance between the surface of the finger and the sensing structure, since a relatively large capacitance is required, the protective layer needs to be made very thin, so it is quite sensitive to scratching and ESD (electrostatic discharge).

[0004] As an active capacitive fingerprint sensor, there is one that supplies an excitation signal to a finger through a conductive structure and measures the charge variation that the sensing structure of the sensor array acquires (see Patent Document 1). Since the potential difference between the surface of the finger touching the sensor array and the sensing structure of the sensor array is low for a dry finger, the acquisition sensitivity of the fingerprint pattern becomes low.

[0005] Also, as another active capacitive fingerprint sensor, when supplying an excitation signal to the finger from the sensing electrode, instead of using a conductive driving structure, the low potential (sensor ground) and high potential of the power supply voltage of the sensor are varied with respect to the device reference potential (device ground), and the reference potential (sensor ground) of the sensor array is oscillated with respect to the potential of the finger. When the sensor ground is oscillated, the potential of the sensing structure of the sensor array oscillates up and down with respect to the device reference potential, and also oscillates up and down with respect to the potential of the finger touching the sensor array. By measuring the variation of the charge carried by the sensing structure due to the change in the voltage between the finger and the sensing structure, the distance between the surface of the finger and the sensing structure can be estimated. In this way, fingerprints can be sensed without a conductive structure for supplying an excitation signal to the finger (see Patent Document 2).

[0006] Since this fingerprint sensing depends on the varying potential of the finger, it is the same for fingers with different potentials and can improve the quality of the fingerprint pattern of dry fingers. Also, the finger can be grounded by the conductive part of the device. Since the amplitude of the finger excitation signal is not limited by the power supply voltage to the sensor array, it becomes possible to use a thicker protective film covering the sensing structure, resulting in a stronger fingerprint sensor.

[0007] Also, in the case of an active capacitive fingerprint sensing system and an electronic device equipped with a conductive housing, by arranging the potential of the conductive housing to be maintained at least intermittently at the reference potential of the electronic device, for example, electrical ground, the conductive housing can satisfy any additional electrical functions of the electronic device while helping to acquire fingerprint patterns in common mode noise and different electrical characteristics (wet / dry) of the finger. And by having the housing connection circuit configuration include an ESD protection circuit configuration, it is also possible to prevent electrostatic discharge from damaging the fingerprint sensing circuit configuration or other parts of the metal card.

[0008] Also, it switches between a signal tracking state in which the potential of the conductive housing is made to follow the finger excitation signal during fingerprint pattern acquisition and a reference potential state in which the potential of the conductive housing is maintained at the reference potential of the electronic device It can be provided with an active circuit configuration that can be controllably replaced. By making the potential of the conductive housing follow the finger excitation signal, the functionality can be enhanced as an active capacitive fingerprint sensing system.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] When mounting the above-mentioned passive capacitive fingerprint sensor on a metal card, Since the capacitance between the finger surface and the sensing structure is passively read out, the sensitivity becomes low with a dry finger. Also, since the protective layer of the fingerprint sensor is very thin, there is a problem that it becomes quite sensitive to scratching and ESD. Further, when mounting a passive capacitive fingerprint sensor on a metal card using a metal plate on the front side of the card, in addition to the metal plate which is a part of the metal card around the fingerprint sensor, a conductive finger contact structure for making conductive contact with the user's finger when the fingerprint sensing system is used is required. The conductive finger contact structure needs to be insulated from the metal plate, which has a problem of affecting the card design.

[0011] Also, when mounting an active capacitive fingerprint sensor on a metal card, By connecting the ground of the internal circuit to the metal plate serving as the conductive housing, it is advantageous for acquiring fingerprint patterns in common-mode noise and different electrical characteristics of fingers (wet / dry). Furthermore, since the housing connection circuit configuration includes an ESD protection circuit configuration, it is possible to prevent electrostatic discharge from damaging the fingerprint sensing circuit configuration and other parts of the metal card. Also, since there is no need to separately provide a conductive finger contact structure, a more flexible card design can be realized.

[0012] Incidentally, in a metal card capable of non-contact communication, in order to obtain sufficient power from the antenna, it is preferable to insert a magnetic sheet, such as a ferrite sheet, between the metal plate and the antenna circuit that can suppress eddy currents generated on the metal surface and well focus the magnetic flux from the antenna. In a metal fingerprint authentication card, in order to operate the fingerprint sensor, read, acquire, and collate the user's fingerprint with the registered fingerprint data for authentication, more power is required than in a normal metal card, and for that purpose, it is preferable to insert a magnetic sheet. However, when a magnetic sheet is provided between the film-like substrate on which the antenna circuit is arranged and the metal plate, in order to electrically connect the ground arranged on the same film-like substrate and the metal plate, it is necessary to closely contact and conduct the ground on the film-like substrate and the metal plate through a conductor that penetrates the magnetic sheet in some way.

[0013] In view of the above problems, an object of the present invention is to provide a metal fingerprint authentication card that is advantageous for acquiring fingerprint patterns in common-mode noise and different electrical characteristics of fingers (wet / dry) by closely contacting and conducting the ground pattern formed on the film-like substrate to the metal plate serving as the conductive housing, and furthermore, since the circuit configuration inside the film-like substrate includes an ESD protection circuit configuration, it is possible to prevent electrostatic discharge from damaging the fingerprint sensing circuit configuration and other parts of the metal card.

Means for Solving the Problems

[0014] In order to solve the above problems in the present invention, a first aspect of the present invention is a metal fingerprint authentication card in which a film-shaped substrate and a magnetic sheet laminated on the film-shaped substrate are integrated by sandwiching and laminating them with front and back card substrates, at least a part of the front card substrate of the front and back card substrates contains metal, the film-shaped substrate is provided with an external connection terminal for communicating with an external device, an active capacitive fingerprint sensor for acquiring fingerprint data of a user, a wiring pattern for connecting each component, a loop antenna circuit for performing non-contact communication, a fingerprint registration unit which is a memory in which the fingerprint data of the user is registered, and a fingerprint verification processing unit for comparing and verifying the fingerprint of the user read by the fingerprint sensor and the fingerprint data registered in the fingerprint registration unit, and a ground pattern is mounted, the film-shaped substrate is provided with a U-shaped slit so as to surround the ground pattern, and the magnetic sheet is provided with a U-shaped slit that overlaps with the U-shaped region of the film-shaped substrate and has an opposite orientation, which is a characteristic of the metal fingerprint authentication card.

[0015] When laminating the magnetic sheet on the film-shaped substrate, the U-shaped slit portions of the film-shaped substrate and the magnetic sheet are alternately overlapped, and the inner region of the slit of the magnetic sheet is inserted from the slit of the film-shaped substrate, so that in the portion of the ground pattern, the film-shaped substrate overlaps on the magnetic sheet, and the ground pattern formed on the film-shaped substrate is positioned at the top. And it is possible to bring the metal plate laminated thereon into close contact with the ground pattern to make it conductive.

[0016] Moreover, a second aspect of the present invention is the metal fingerprint authentication card according to claim 1, characterized in that the circuit configuration inside the film-shaped substrate includes an ESD protection circuit configuration.

[0017] Integrated circuits (ICs) are sensitive to ESD, and the high peak voltage and current of ESD can cause damage to the IC. To protect an electrostatic-sensitive IC from ESD, an ESD protection circuit can be created to prevent electrostatic discharge from damaging the fingerprint sensing circuit configuration or other parts of the metal card by flowing the current to the ground.

Advantages of the Invention

[0018] According to the present invention, by closely attaching and conducting the ground pattern formed on the film-like substrate to the metal plate serving as the conductive housing, it is advantageous for fingerprint pattern acquisition in common-mode noise and different electrical characteristics of fingers (wet / dry). Furthermore, since the circuit configuration inside the film-like substrate includes an ESD protection circuit configuration, it is possible to provide a metal fingerprint authentication card that can prevent electrostatic discharge from damaging the fingerprint sensing circuit configuration or other parts of the metal card. Since the ground pattern formed on the film-like substrate is used, there is no need to separately provide a conductor that penetrates the magnetic sheet, and the ground of the metal plate and the circuit board can be conducted while suppressing the cost and the unevenness of the thickness in the thickness direction of the card. Also, since there is no need to separately provide a conductive finger contact structure, a more flexible card design can be realized.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0020] Embodiments of the metal fingerprint authentication card according to the present invention will be described with reference to the drawings. Here, the drawings are schematic, and the relationships between the planar dimensions, the ratios of the thicknesses of the respective layers, etc. are different from the actual ones. Further, the embodiments shown below illustrate the configurations for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the following specific materials, shapes, structures, etc. of the components. is not.

[0021] <Basic Configuration> FIG. 1 is a plan view showing a metal fingerprint authentication card 1 according to an embodiment of the present invention. An external connection terminal 3 for contact communication and an active capacitance type fingerprint sensor 4 for reading a fingerprint and acquiring fingerprint data are exposed on a base material 2 on the front side of the card. Inside, there is an IC module that stores fingerprint data, collates the fingerprint data generated by the fingerprint sensor with the stored fingerprint data to determine whether they match, and communicates with an external device according to the collation result. In this embodiment, as communication means for communicating with an external device, both contact data communication and non-contact data communication are provided, but only non-contact data communication may be used.

[0022] The base material 2 on the card surface is composed of a metal material such as stainless steel or titanium with at least a part of the layer having a thickness of 100 to 500 μm. Openings for exposing the external connection terminal substrate and the fingerprint sensor are provided in advance on the metal plate by laser or cutting. On the card surface 2, the contact terminal and the fingerprint sensor are exposed through the openings of the metal plate. A resin sheet may be provided outside the metal plate, and printing may be performed on the surface of the metal plate or the resin sheet. However, in order to ensure that the metal plate and the user's finger always come into direct contact when the user touches the fingerprint sensor, it is necessary to provide a state without printing or a region without printing at regular intervals in the area around the fingerprint sensor.

[0023] Figure 2 is a plan view showing components mounted on a film-shaped substrate 10 disposed inside the front and back card substrates. As shown in Figure 2, an external connection terminal 3 for communicating with an external device, a capacitive fingerprint sensor 4 for reading and acquiring fingerprint data of a user, a fingerprint registration unit which is a memory where the user's fingerprint data is registered, and a fingerprint matching processing unit for comparing and collating the fingerprint of the user acquired by the fingerprint sensor with the fingerprint data registered in the fingerprint registration unit are provided in an IC module 5. A wiring pattern 7 for connecting each component and a loop antenna circuit 8 for performing non-contact communication are mounted on the front surface of the film-shaped substrate 10 with a conductive bonding material such as solder or ACF, and a ground pattern 6 is provided.

[0024] The IC module 5 is not exposed on the surface of the card 1 and is encapsulated in the card 1. In order to accommodate the IC module 5, a concave cavity is formed in the region located above the IC module 5 of the metal plate.

[0025] The film-shaped substrate 10 has circuit patterns formed by etching aluminum, copper, etc. on the front and back of a plastic substrate such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), or polyimide (PI). The external connection terminal substrate 3 has copper patterns formed on both sides of a substrate such as glass epoxy or polyimide, and those with a plating treatment such as nickel, palladium, or gold on the copper patterns are used.

[0026] A U-shaped slit 9 is arranged on the front surface of the film-shaped substrate 10 so as to surround the ground pattern 6 connected to the circuit ground. The ground pattern 6 preferably has a size of 1 cm in order to reduce the contact resistance with the metal plate and make conduction more reliable. 2 It is preferably the above. Also, by arranging it away from the center line of the card 1, it is preferable to minimize the stress applied to the ground pattern 6 portion when the card 1 is bent.

[0027] FIG. 3 is a diagram showing the magnetic sheet 20 of the present embodiment. By inserting the magnetic sheet 20 between the metal plate and the film-like substrate 10, the generation of eddy currents on the metal surface is suppressed, and by well focusing the magnetic flux from the antenna, a series of operations for fingerprint authentication (operating the fingerprint sensor, reading, acquiring the user's fingerprint, and collating it with the registered fingerprint data for authentication) can obtain the required power from non-contact communication. In the magnetic sheet 20, a U-shaped slit 16 that overlaps the U-shaped slit 9 of the film-like substrate 10 and has an opposite orientation is arranged, and openings (13, 14, 15 respectively) for inserting the external connection terminal substrate 3, the fingerprint sensor 4, and the IC module 5 are provided. The thickness of the magnetic sheet 20 is 50 μm to 200 μm. The U-shaped slit 16 is arranged to overlap the U-shaped slit 9 of the film-like substrate 10 and has an opposite orientation, and openings (13, 14, 15 respectively) for inserting the external connection terminal substrate 3, the fingerprint sensor 4, and the IC module 5 are provided. The thickness of the magnetic sheet 20 is 50 μm to 200 μm.

[0028] FIG. 4 is a plan view showing a state in which the magnetic sheet 20 is laminated on the film-like substrate 10 of the present embodiment. When laminating the magnetic sheet 20 on the film-like substrate 10, the U-shaped slit portions (9 and 16 respectively) are overlapped alternately, and from the slit 9 of the film-like substrate 10, the inner region of the slit 16 of the magnetic sheet 20 is inserted under the film-like substrate 10, so that on the ground pattern 6 portion, the film-like substrate 10 overlaps the magnetic sheet 20. In this way, since they are overlapped alternately in the ground pattern 6, while making the thickness after lamination the same between the ground pattern 6 portion and other portions, on the ground pattern 6 portion, the film-like substrate 10 overlaps the magnetic sheet 20, the ground pattern 6 formed on the film-like substrate 10 is positioned at the top, and the metal plate laminated thereon can be brought into close contact with the ground pattern 6 to conduct. Further, by applying an adhesive to both surfaces of the magnetic sheet 20 during lamination, while enhancing the adhesion during lamination, it is possible to prevent the adhesive from adhering to the ground pattern 6 and inhibiting the conduction with the metal plate.

[0029] FIG. 5 is a schematic cross-sectional view showing the layer structure between X-X' of the ground pattern portion 6 in a state where the magnetic sheet 20 is laminated on the film-like substrate 10 (see FIG. 4). The laminate obtained by laminating the magnetic sheet 20 on the film-like substrate 10 is sandwiched between a metal plate 22 and exterior resins (21, 25) such as PVC and PET-G, and laminated by hot pressing to integrate the card base material. Here, instead of laminating by hot pressing, the card base material can also be integrated by laminating using a two-component curable resin, a room-temperature curable resin, or a UV curable resin in a cold pressing method. The sheet-like card base material integrated by lamination is formed into individual card shapes by laser or cutting.

[0030] As shown in FIG. 5, in the portion of the ground pattern 6, the film-like substrate 10 overlaps the magnetic sheet 20, the ground pattern 6 formed on the film-like substrate 10 is located at the uppermost part, and the ground pattern 6 and the metal plate 22 are in close contact with each other.

[0031] By applying pressure for lamination, the adhesive layer 23 becomes thinner in the U-shaped portion, and the metal plate 22 and the ground pattern 6 can be brought into close contact and electrically connected while suppressing the thickness unevenness in the thickness direction of the card 1. Further, in order to make the adhesion of the ground pattern 6 to the metal plate 22 stronger during lamination, a pattern having the same shape as the ground pattern 6 is formed on the surface of the film-like substrate 10 opposite to the ground pattern 6, and the U-shaped portion can be formed into a card with the adhesive layer 23 in a thinner state.

[0032] Although not shown in the drawings of this embodiment, by providing an ESD protection circuit configuration in the circuit configuration of the film-like substrate 10, it is possible to prevent electrostatic discharge from damaging the fingerprint sensing circuit configuration and other parts of the metal card.

Example

[0033] Hereinafter, card examples in which the present invention is specifically implemented are shown. Card dimensions: JIS X6301:2005 (ISO / IEC) Long side: 85.47~85.72 mm (nominal value 85.6 mm) Thickness: 0.68~0.84 mm (nominal value 0.76 mm)

Explanation of symbols

[0034] 1 ··· Metal fingerprint authentication card 2 ··· Front substrate of the metal fingerprint authentication card 3 ··· External connection terminal 4 ··· Active capacitance type fingerprint sensor 5 ··· IC module 6 ··· Ground pattern 7 ··· Wiring pattern 8 ··· Loop antenna circuit 9 ··· Slit (inside the film-like substrate) 10 ··· Film-like substrate 13 ··· Opening for external connection terminal 14 ··· Opening for fingerprint sensor 15 ··· Opening for IC module 16 ··· Slit (inside the magnetic sheet) 20 ··· Magnetic sheet 21 ··· Exterior resin layer (surface) 22 ··· Metal plate 23 ··· Adhesive layer 24 ··· Intermediate resin layer 25 ··· Exterior resin layer (back surface)

Claims

1. A metal fingerprint authentication card integrated by sandwiching and laminating a film-shaped substrate and a magnetic sheet laminated on the film-shaped substrate between front and back card base materials, wherein at least a part of the front card base material among the front and back card base materials includes a metal plate, the film-shaped substrate is provided with an external connection terminal for communicating with an external device, an active capacitance type fingerprint sensor for acquiring fingerprint data of a user, a wiring pattern for connecting each component, a loop antenna circuit for performing non-contact communication, a fingerprint registration unit which is a memory for registering the fingerprint data of the user, and a fingerprint matching processing unit for comparing and matching the fingerprint of the user read by the fingerprint sensor with the fingerprint data registered in the fingerprint registration unit, and a ground pattern is mounted, a U-shaped slit is provided in the film-shaped substrate so as to surround the ground pattern, and a U-shaped slit is provided in the magnetic sheet so as to overlap with the U-shaped region of the film-shaped substrate and face in the opposite direction. A metal fingerprint authentication card characterized by this.

2. The metal fingerprint authentication card according to claim 1, characterized in that the circuit configuration inside the film-shaped substrate includes an ESD protection circuit configuration.

Images