JP7765079B2 - Fingerprint authentication device - Google Patents

Description

The present invention relates to a fingerprint authentication device.

Patent Document 1 below discloses a technology in which a fingerprint reader installed in a terminal device has a conductive plate connected to the substrate at ground potential in the fingerprint reader section, and when a user's finger is placed on the fingerprint reader section, static electricity stored on the user's finger is removed via the plate.

Japanese Patent Application Laid-Open No. 2001-5951

However, the technology in Patent Document 1 uses a configuration in which the plate is fixed to the fingerprint reading device using screws, springs, etc., which requires the plate to be provided with a fixing portion for fixing the plate, which increases the size of the plate and, as a result, may increase the size of the entire device.

A fingerprint authentication device according to one embodiment includes a fingerprint sensor unit having a detection surface that detects the fingerprint of an operator's finger, a substrate on which the fingerprint sensor unit is mounted, a metal frame that is placed over the substrate, and a holding member that holds the substrate. The fingerprint authentication device also includes a conductive elastic body that is placed between the metal frame and the substrate near the fingerprint sensor unit and connects the metal frame to the ground potential of the substrate.

According to one embodiment of the fingerprint authentication device, it is possible to prevent the overall size of the device from increasing.

FIG. 1 is an external perspective view of a fingerprint authentication device according to an embodiment; FIG. 1 is an exploded perspective view of a fingerprint authentication device according to an embodiment; 2 is a cross-sectional view of the fingerprint authentication device according to the embodiment taken along the line AA in FIG. 1. FIG. 1 is a perspective view of the appearance of a fingerprint authentication device according to an embodiment, seen from below; FIG. 1 is a diagram illustrating an assembly procedure for a fingerprint authentication device according to an embodiment. FIG. 1 is a diagram illustrating an assembly procedure for a fingerprint authentication device according to an embodiment. FIG. 1 is a diagram illustrating an assembly procedure for a fingerprint authentication device according to an embodiment. FIG. 1 is a diagram illustrating an assembly procedure for a fingerprint authentication device according to an embodiment.

One embodiment will be described below with reference to the drawings.

(Configuration of fingerprint authentication device 100)
Fig. 1 is an external perspective view of a fingerprint authentication device 100 according to an embodiment. Fig. 2 is an exploded perspective view of the fingerprint authentication device 100 according to an embodiment. Fig. 3 is a cross-sectional view of the fingerprint authentication device 100 according to an embodiment taken along the AA cross-sectional line in Fig. 1. Fig. 4 is an external perspective view of the fingerprint authentication device 100 according to an embodiment as viewed from the bottom (negative side of the Z axis).

For the sake of convenience, in the following explanation, the X-axis direction will be referred to as the left-right direction, the Y-axis direction as the front-back direction, and the Z-axis direction as the up-down direction. However, the positive X-axis direction will be referred to as the right direction, the positive Y-axis direction as the forward direction, and the positive Z-axis direction as the upward direction. These indicate relative positional relationships within the device and do not limit the installation direction or operating direction of the device. Anything that has the same relative positional relationship within the device, even if the installation direction or operating direction is different, is within the scope of the present invention.

The fingerprint authentication device 100 shown in Figure 1 is a device that is installed, for example, on an operation panel mounted in the passenger compartment of a vehicle such as an automobile, and detects the fingerprint of an operator's finger.

As shown in Figures 1 to 4, the fingerprint authentication device 100 includes a metal frame 110, a fingerprint sensor unit 120, a flexible substrate 130, a holding member 140, and a conductive elastic body 150.

The metal frame 110 is a metal member that is placed on top of the base 131 of the flexible substrate 130. When viewed from above, the metal frame 110 has a rectangular frame shape that surrounds the fingerprint sensor unit 120 mounted on the base 131 of the flexible substrate 130. The metal frame 110 is conductive and is connected to the ground potential of the flexible substrate 130 via the conductive elastic body 150.

When an operator places his/her finger on the detection surface 120A of the fingerprint sensor unit 120, the metal frame 110 dissipates static electricity stored on the operator through contact with the metal frame 110 to the ground potential of the flexible substrate 130, thereby preventing damage to the fingerprint sensor unit 120 due to static electricity. The metal frame 110 sandwiches the base 131 of the flexible substrate 130 and the conductive elastic body 150 between itself and the holding member 140 (see Figure 3).

The metal frame 110 has a flat portion 111, a raised portion 112, and four claw portions 113. The flat portion 111 is parallel to the detection surface 120A of the fingerprint sensor unit 120. An opening 111A that is rectangular when viewed from above is formed in the center of the flat portion 111. The opening 111A is formed to expose at least a portion of the detection surface 120A of the fingerprint sensor unit 120.

The raised portion 112 is a portion that is raised upward from the flat portion 111 by drawing, and is formed in a rectangular shape that surrounds the edge of the opening 111A. The four claw portions 113 are an example of a "fixed portion" and are thin plate-like portions that extend downward from the vicinity of each of the four corners of the flat portion 111.

Specifically, the two claws 113 extend downward from the front end (end on the positive side of the Y-axis) and rear end (end on the negative side of the Y-axis) of the right edge (edge on the positive side of the X-axis) of the flat portion 111. The other two claws 113 extend downward from the front end (end on the positive side of the Y-axis) and rear end (end on the negative side of the Y-axis) of the left edge (edge on the negative side of the X-axis) of the flat portion 111.

Each claw 113 has a slit 113A formed at its tip. Each claw 113 is bent at approximately a right angle along the side surface 140C and bottom surface 140B of the holding member 140, and with the protrusions 141 of the holding member 140 inserted into the slits 113A, the protrusions 141 of the holding member 140 are crimped and fixed to the protrusions 141 of the holding member 140. With each of the four claws 113 fixed to each of the four protrusions 141, the metal frame 110 is fixed to the holding member 140 with the conductive elastic body 150 compressed. Details of the assembly procedure will be described later.

The fingerprint sensor unit 120 is a thin plate-like member mounted on the upper surface of the base 131 of the flexible substrate 130. When viewed from above, the fingerprint sensor unit 120 has a rectangular shape. The fingerprint sensor unit 120 has a detection surface 120A on its upper surface, and detects the fingerprint of an operator's finger on this detection surface 120A. For example, the fingerprint sensor unit 120 can optically detect the fingerprint of a finger placed on the detection surface 120A and output a fingerprint detection signal indicating the detected fingerprint pattern. However, the detection method of the fingerprint sensor unit 120 is not limited to optical, and other detection methods such as electrostatic detection may also be used.

The flexible substrate 130 is an example of a "substrate." The flexible substrate 130 is a substrate in which a conductive circuit is covered with a bendable, insulating resin sheet-like member. The flexible substrate 130 can transmit fingerprint detection signals detected by the fingerprint sensor unit 120 to the outside.

In the example shown in Figures 1 to 3, the flexible substrate 130 has a base portion 131, a folded portion 132, a flat portion 133, a lead-out portion 134, and a connection portion 135. The base portion 131 has a rectangular shape when viewed from above, and is the portion on which the fingerprint sensor unit 120 is mounted. The base portion 131 is supported by the holding member 140 by being placed on top of the holding member 140.

The folded portion 132 extends downward (in the negative direction of the Z axis) from the right end (end on the positive side of the X axis) of the base portion 131, folding the extension direction of the flexible substrate 130 from the right (positive direction of the X axis) to the left (negative direction of the X axis) and connecting to the flat portion 133. The flat portion 133 extends leftward (in the negative direction of the X axis) from the bottom end (end on the negative side of the Z axis) of the folded portion 132, and is sandwiched between a mating component (not shown) and the underside 140B via the elastic block 136 when positioned by the positioning protrusion 142 on the underside 140B of the holding member 140.

The draw-out portion 134 extends downward (in the negative Z-axis direction) from the left end (the end on the negative X-axis side) of the flat portion 133. The connection portion 135 is provided at the end of the draw-out portion 134 and is connected to a connector (not shown) that leads to the outside.

The holding member 140 is a flat, resin member that is placed on the underside of the base 131 of the flexible substrate 130. When viewed from above, the holding member 140 has a generally rectangular shape. The base 131 of the flexible substrate 130 is placed on the support surface 140A, which is its upper surface, and the holding member 140 supports the base 131 of the flexible substrate 130 from below.

Four protrusions 141 are provided at each of the four corners of the underside 140B of the holding member 140, protruding downward (in the negative Z-axis direction). Each of the four protrusions 141 is an example of a "fixing portion," and, as described above, is inserted into the slit 113A of the claw portion 113 of the metal frame 110 and crimped to fix the claw portion 113.

In this embodiment, the protrusion 141 is crimped using thermal crimping, which applies pressure and heat, but other crimping methods (for example, crimping methods that apply pressure only) may also be used. Note that the protrusion 141 shown in Figure 4 is compressed in the height direction by crimping, and has a roughly cylindrical shape with a radial dimension greater than its height. However, the protrusion 141 before compression has a roughly cylindrical shape with a height dimension greater than its radial dimension, as shown in Figure 5.

The conductive elastic body 150 is a member that is conductive and elastic. The conductive elastic body 150 is provided on a ground pattern (not shown) on the upper surface of the base 131 of the flexible substrate 130, and in the vicinity of the periphery of the fingerprint sensor unit 120. Although not shown, the ground pattern formed on the base 131 is connected to the ground potential of the device in which the fingerprint authentication device 100 is installed.

When the metal frame 110 is fixed to the holding member 140, the conductive elastic body 150 is sandwiched between the metal frame 110 and the base 131. As a result, the conductive elastic body 150 connects the metal frame 110 to the ground potential of the flexible substrate 130. In this embodiment, the conductive elastic body 150 is adhered to the ground pattern on the upper surface of the base 131 of the flexible substrate 130 with conductive double-sided tape. However, this is not limiting, and for example, the conductive elastic body 150 may be adhered to the lower surface of the flat portion 111 of the metal frame 110 (at a position facing the ground pattern) with conductive double-sided tape.

In this embodiment, the conductive elastic body 150 is made of any of conductive urethane, conductive silicone, conductive polyethylene, and conductive foam. Furthermore, in this embodiment, the fingerprint authentication device 100 includes two conductive elastic bodies 150 provided at two diagonally opposite positions near the periphery of the fingerprint sensor unit 120. However, the number and arrangement of the conductive elastic bodies 150 are not limited to this.

The fingerprint authentication device 100 configured as described above can detect the operator's fingerprint by placing the operator's finger on the detection surface 120A of the fingerprint sensor unit 120 exposed through the opening 111A of the metal frame 110. The fingerprint authentication device 100 can then output a fingerprint detection signal indicating the detected fingerprint pattern, etc., to the outside via the flexible substrate 130. At this time, when the operator's finger comes into contact with the raised portion 112 of the metal frame 110, the fingerprint authentication device 100 dissipates the static electricity stored on the operator to the ground potential of the flexible substrate 130 via the metal frame 110 and the conductive elastic body 150, thereby preventing damage to the fingerprint sensor unit 120 due to static electricity.

(Assembling Procedure of Fingerprint Authentication Device 100)
5 to 8 are diagrams for explaining the assembly procedure of the fingerprint authentication device 100 according to one embodiment. Note that, in explaining the assembly procedure below, it is assumed that the fingerprint sensor unit 120 has been mounted in advance on the base 131 of the flexible substrate 130 by solder bumps or the like.

First, as shown in FIG. 5, the holding member 140 is placed between the base 131 and the flat portion 133 of the flexible substrate 130, thereby holding the flexible substrate 130 with the holding member 140. At this time, the base 131 of the flexible substrate 130 is held by the support surface 140A of the holding member 140.

Furthermore, as shown in Figure 5, conductive elastic bodies 150 are installed at each of two diagonal positions (both on the ground pattern) on the top surface of the base 131 of the flexible substrate 130.

Then, as shown in Figure 6, the metal frame 110 is placed over the base 131 of the flexible substrate 130. At this time, the conductive elastic body 150 is crushed between the flat surface 111 of the metal frame 110 and the base 131 of the flexible substrate 130.

Next, as shown in Figure 7, each of the four claws 113 on the metal frame 110 is bent inward at a substantially right angle so as to align with the underside 140B of the holding member 140. This causes the protrusions 141 on the holding member 140 to be inserted into the slits 113A of each of the four claws 113.

Then, as shown in FIG. 8, each of the four protrusions 141 on the holding member 140 is compressed in the height direction and crimped, thereby fixing each of the four claws 113 on the metal frame 110 to the holding member 140. As a result, the metal frame 110 is fixed to the holding member 140 while connected to the ground potential of the flexible substrate 130 via the conductive elastic body 150, resulting in the state shown in FIG. 4.

At this time, the conductive elastic body 150 is crushed between the flat portion 111 of the metal frame 110 and the base portion 131 of the flexible substrate 130, and its restoring force causes it to abut firmly against both the metal frame 110 and the flexible substrate 130, maintaining a stable connection of the metal frame 110 to the ground potential via the conductive elastic body 150. The conductive elastic body 150 also functions as a buffer, absorbing variations in the bending position of the claw portions 113 of the metal frame 110 and dimensional variations in related components, maintaining the metal frame 110 in a fixed state without any rattle.

(effect)
As described above, the fingerprint authentication device 100 according to one embodiment comprises a fingerprint sensor unit 120 having a detection surface 120A for detecting the fingerprint of an operator's finger, a flexible substrate 130 on which the fingerprint sensor unit 120 is mounted, a metal frame 110 that is provided over the flexible substrate 130 and that can be contacted by a finger placed on the detection surface 120A, and a holding member 140 that holds the flexible substrate 130. The fingerprint authentication device 100 further comprises a conductive elastic body 150 that is provided between the metal frame 110 and the flexible substrate 130, in the vicinity of the fingerprint sensor unit 120, and that connects the metal frame 110 to the ground potential of the flexible substrate 130.

As a result, the fingerprint authentication device 100 according to one embodiment does not require screw fastening parts or the like required to connect the metal frame 110 to ground potential, allowing the area of the metal frame 110 to be reduced. Furthermore, since there is no risk of the conductive adhesive unintentionally spreading, as with conductive adhesive, the clearance between the conductive elastic body 150 and the fingerprint sensor unit 120 can be reduced, thereby preventing the overall size of the device from increasing.

In one embodiment of the fingerprint authentication device 100, the holding member 140 has a protrusion 141, and the metal frame 110 has a claw portion 113. The claw portion 113 is fixed to the protrusion 141 of the holding member 140, thereby fixing the conductive elastic body 150 to the holding member 140 in a compressed state.

As a result, the fingerprint authentication device 100 according to one embodiment can stably maintain the state in which the conductive elastic body 150 is compressed, so that even if the dimensions of the components vary, the metal frame 110 does not rattle, and the fixed state of the metal frame 110 and its connection to the ground potential can be stably maintained.

In one embodiment of the fingerprint authentication device 100, the metal frame 110 has a flat portion 111 parallel to the detection surface 120A, an opening 111A formed in the center of the flat portion 111 and exposing at least a portion of the detection surface 120A, a raised portion 112 that is provided by being raised so as to surround the opening 111A, and a plurality of claw portions 113 that extend downward from the edge of the flat portion 111, each of which is bent along the side surface 140C and the bottom surface 140B of the holding member 140.

As a result, the fingerprint authentication device 100 according to one embodiment can easily manufacture the part, since the metal frame 110 can be integrally formed from a single metal plate through a series of press processes, including drawing and bending processes.

In one embodiment of the fingerprint authentication device 100, the holding member 140 has multiple protrusions 141 on its underside 140B, and each of the multiple claws 113 has a slit 113A at its tip, and the protrusions 141 are inserted into the slits 113A and crimped to be fixed to the protrusions 141.

As a result, the fingerprint authentication device 100 according to one embodiment can secure the metal frame 110 to the holding member 140 with a relatively simple procedure and without using any additional parts. Furthermore, the fixed state of the metal frame 110 can be stably maintained.

In one embodiment of the fingerprint authentication device 100, the conductive elastic body 150 is made of conductive urethane, conductive silicone, conductive polyethylene, or conductive foam.

This allows the fingerprint authentication device 100 of one embodiment to have suitable conductivity and elasticity for fixing and grounding the metal frame 110.

Furthermore, the fingerprint authentication device 100 according to one embodiment includes two conductive elastic bodies 150 provided at two diagonal positions around the fingerprint sensor unit 120.

As a result, the fingerprint authentication device 100 according to one embodiment can stably support the metal frame 110 in a well-balanced manner, and can reduce costs compared to a configuration including four conductive elastic bodies 150.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as set forth in the claims.

100 Fingerprint Authentication Device 110 Metal Frame 111 Plane Part 111A Opening Part 112 Raised Part 113 Claw Part (Fixed Part)
113A Slit 120 Fingerprint sensor section 120A Detection surface 130 Flexible substrate (substrate)
131 Base portion 132 Folded portion 133 Planar portion 134 Pull-out portion 135 Connection portion 136 Elastic block 140 Holding member 140A Support surface 140B Lower surface 140C Side surface 141 Protrusion (fixing portion)
142 Positioning protrusion 150 Conductive elastic body

Claims (6)

a fingerprint sensor unit having a detection surface for detecting the fingerprint of an operator's finger;
a substrate on which the fingerprint sensor unit is mounted;
a metal frame provided to cover the substrate;
a holding member for holding the substrate,
a conductive elastic body provided between the metal frame and the substrate in the vicinity of the fingerprint sensor unit, the conductive elastic body connecting the metal frame to a ground potential of the substrate. The holding member has a fixing portion,
The metal frame has a fixed portion, and the fixed portion is fixed to the fixing portion of the holding member, whereby the conductive elastic body is fixed to the holding member in a compressed state.
2. The fingerprint authentication device according to claim 1. The metal frame is
a flat surface parallel to the detection surface;
an opening formed in a center portion of the planar portion and exposing at least a portion of the detection surface;
a raised portion that is raised so as to surround the opening;
a plurality of the fixed portions extending downward from an edge of the flat portion,
Each of the plurality of fixed portions is
The fingerprint authentication device according to claim 2 , wherein the holding member is bent along the side and bottom surfaces of the holding member. The holding member is
The fixing portion has a plurality of fixing portions on the lower surface,
Each of the plurality of fixed portions is
The fingerprint authentication device according to claim 3, wherein the tip portion has a slit, and the fixing portion is inserted into the slit and crimped to be fixed to the fixing portion. 5. The fingerprint authentication device according to claim 1, wherein the conductive elastic body is one of conductive urethane, conductive silicone, conductive polyethylene, and conductive foam. The fingerprint authentication device according to any one of claims 1 to 5, further comprising two of the conductive elastic bodies provided at two diagonal positions around the fingerprint sensor portion.