JPH10314148A - Finger authenticating sensor and mounting structure of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a finger authenticating sensor and the mounting structure of it where authentication precision is improved by almost fixedly taking pressure for pressurizing a finger sensor and hightening the adhesive degree of the finger in terms of time passage. SOLUTION: The finger authenticating sensor 11 constituted by an electyrode string is provided on a mobile structure body 12 like the key of a piano or the key of a keyboard in an information equipment and a reaction force generating mechanism 13 such as a spring, a magnet or an oil dampler, etc., is mounted inside so that the contact relation of the finger with the sensor is stabilized so as to improve authentication precision. Moreover, force balance as against a depressing stroke is kept by reaction force generated by depressing the finger to metallic electrode plate array and resistance between adjacent electrodes or capacitance data is sampled in a certain depressing stroke position so that data is fetched by almost fixed pressure without reliance on an operator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a finger authentication sensor and a mounting structure of the finger authentication sensor, which are frequently used as personal authentication means for securing security of information equipment.

[0002]

2. Description of the Related Art Instead of a conventional optical system as a device for finger collation, a plurality of metal plate electrodes long in a direction perpendicular to the longitudinal direction of a finger are arranged in the longitudinal direction of the finger, and adjacent to the finger when pressed. Japanese Patent Application No. 5-323481 proposes a method using a finger authentication device that uses a signal obtained by sequentially reading the resistance value or capacitance between matching electrodes in the longitudinal direction of a finger and combining them. Since the size of the device can be reduced, it is frequently used as a means for ensuring security of information devices and the like.

However, conventionally, the sensor of the finger authentication device is fixed, so that the pressure generated when a finger is pressed varies from person to person, and this has affected the accuracy of authentication.

[0004]

Conventionally, since the finger authentication sensor using the metal electrode system is fixed, the pressure on the sensor is not uniquely determined by the operator, and the degree of adhesion changes each time due to the difference in pressure. Therefore, the authentication accuracy is affected, and when the pressing is unstable, there is a problem that chattering occurs and the like, and reliability is still lacking.

[0005] The present invention has been made in view of the above circumstances, and a finger that improves the authentication accuracy by taking in the pressure for pressing constantly and increasing the degree of close contact of the finger over time. An object of the present invention is to provide a mounting structure of an authentication sensor and a finger authentication sensor.

[0006]

The mounting structure of the finger authentication sensor according to the present invention is such that a plurality of metal electrode plates which are long in a direction perpendicular to the longitudinal direction of the finger are arranged in the longitudinal direction of the finger, and the fingers are arranged in the metal electrode plate group. When a finger is pressed, finger authentication is performed by sensing the resistance or capacitance between adjacent electrodes, and a mechanism for generating a reaction force when a finger is pressed against each metal electrode plate is added. The plate has a movable structure. A specific mechanism for generating a reaction force includes a buffer member on which a metal plate is placed, and one end in the longitudinal direction is pivotally supported like a hinge, and the shaft is fulcrumed when a finger is pressed against each metal electrode plate. And a viscous resistor such as an oil damper that generates a reaction force according to the moving speed.

Further, the finger authentication sensor of the present invention comprises a movable metal electrode plate array in which a plurality of metal plate electrodes are arranged in a direction orthogonal to the longitudinal direction of the finger, and a finger pressed against the metal electrode plate array. A reaction force generation mechanism that maintains a balance of force with respect to a pressing stroke by a generated reaction force, and a data sampling circuit that samples resistance or capacitance data between adjacent electrodes at a certain pressing stroke position. I do.

[0008] This makes it possible to stabilize the contact relationship between the finger and the sensor, thereby contributing to an improvement in authentication accuracy.

[0009]

1 to 3 show an embodiment of a mounting structure of a finger authentication sensor according to the present invention.

In the embodiment shown in FIG. 1, a metal plate electrode 11 serving as a sensor and a buffer material 1 on which a plurality of such metal plate electrodes are mounted are shown.
2, one end of the cushioning member 12 in the longitudinal direction is pivotally supported to be rotatable about the shaft, and a reaction force is applied to the shaft of the cushioning member 12 as a fulcrum when a finger is pressed against each metal electrode plate. Is provided with a structure 13 such as a spring or a magnet for generating the above. That is, the metal electrode 11 serving as a sensor is held like a keyboard of a piano, one of which is rotatable about an axis like a hinge 12, and the other is a fixed or floating finger or a finger such as a spring or repulsion magnet 3 which is not fixed. A mechanism that has a reaction force against the pressing of the device is mounted.

The embodiment shown in FIG.
1 is received by the cushioning material 22, and the entire cushioning material 22 including the electrodes sinks when pressed down like a keyboard of an information device, and a structure such as a spring or a repulsion magnet 23 is provided under the cushioning material 22. It shows how to implement it and have a reaction force against finger pressing.

In each of the above-described embodiments, the finger is pressed against the reaction force that is refreshed by the spring or the repulsion magnet, so that the force is statically balanced with the pressing stroke. By sampling the data at a certain pressing stroke position as indicated by a dashed line, it is possible to capture the data with a substantially constant pressing force.

At this time, as a variable element of the pressing force, there is an inertial weight of the key on which the sensor is mounted, but the electrode type sensor is in a negligible range because the sensor portion can be made extremely lightweight.

The embodiment shown in FIG. 3 shows an example in which a viscous resistor such as an oil damper is used as a structure having a reaction force. The hinge type shown in FIG. 1 and the whole shown in FIG. Can be used in any of the sinking forms. The viscous resistor 33 such as an oil damper is characterized in that it generates a reaction force according to the moving speed. Therefore, since the reaction force is generated in proportion to the speed at which the operator presses the finger against the sensor, even if the operator has a habit of pressing the finger in a short time, it is necessary to press the finger until the predetermined stroke is reached. A certain amount of time is required, and the time during which the sensor and the finger are in close contact is maintained to some extent. As a result, a predetermined contact time can be obtained, and the accuracy of authentication can be improved.

FIG. 4 is a diagram showing a configuration example of the finger authentication sensor of the present invention.

The finger collation by inputting an electrode array will be described with reference to FIG. In the figure, reference numeral 41 denotes a metal plate electrode array having an electrode interval of about 1/10 mm. Number of electrodes,
That is, the length of the electrode array 41 in the longitudinal direction is generally set to a length completely including the second joint from the tip of the finger. A finger whose signal is to be detected is pressed against the electrode 41 in a direction orthogonal to the electrode arrangement direction. At this time, the resistance value of the finger surface between the adjacent electrodes is sequentially read by switching the analog switch 42 in the length direction of the finger. When a finger is pressed against n electrodes, the resistance value between the electrodes changes according to the contact area of the finger in contact between adjacent contact electrodes. The i-th inter-electrode resistance value at this time is R (i). As shown in the figure, a reference resistor Rref44 and a constant voltage power supply Vo43 are connected between two adjacent electrodes via an analog switch 42. At this time, the potential difference V (i) between both ends of the reference resistor Rref44 is given by Expression (1) shown in FIG.

By switching the analog switch 42, the potential difference is sequentially read in the length direction of the finger, and is converted into a digital signal by the A / D converter 46 through the sample and hold circuit 45. The timing pulse generator 47 generates a signal for controlling the switching of the analog switch 42 and the sample timing of the sample and hold circuit 45. The signal is, for example, as shown in FIG. That is,
Switching the analog switch 42 at the falling edge of the signal,
At the rising edge, the sample-and-hold circuit 45 holds the potential difference V (i) shown in the equation (1). The signal V (i) obtained in this way is as shown in FIG. 6, for example. FIG.
Shows an example of the projection signal. That is, V (i) has a large value in a portion where the contact area between the finger and the electrode is large, and V (i) has a small value because the contact area is small in the lateral wrinkles in the first joint and the second joint. V (i) has a steep dip in that portion.

FIG. 7 is a block diagram showing a configuration example of an information device having a finger authentication function. In the embodiment shown in FIG.
A finger authentication device is mounted on an information device 71 such as a PC.
The pattern input section 72 is a section that captures the projection signal V (i) of the entire finger according to the difference in the contact area between the finger and the electrode 41 shown in FIG. The authentication control unit 73 is a unit that performs a process related to verification of whether or not the user is a user, which will be described later. The read / write device 74 reads the personal data registered in advance in the memory area of the RAM or the hard disk in the information processing device 71 in the collation processing by the authentication control unit 73, or conversely, converts the personal data into the personal authentication data. This is the part that performs the process of writing to. Here, comparison and collation are performed, and identity verification is performed.

As described above, according to the present invention, a finger authentication sensor constituted by an electrode row is provided on a movable structure such as a keyboard of a piano or a key of a keyboard of an information device, and a spring, By mounting a reaction force generating mechanism such as a magnet and an oil damper, the contact relationship between the finger and the sensor is stabilized, and the authentication accuracy is improved.

[0020]

As described above, according to the present invention, the following effects can be obtained.

(1) The force of pressing the finger against the electrode row is kept almost constant at the same pressing stroke point, and the contact state between the sensor and the finger with high reproducibility is maintained, so that the authentication accuracy is improved. Further, when a hinge-like structure is used, a derivative effect is obtained such that the wiring to the sensor can be easily connected.

(2) When an aging resistor such as an oil damper is used as the reaction force generating mechanism, the pressure is generated in accordance with the speed at which the operator presses the finger against the sensor. It takes a certain amount of time to press until a predetermined stroke is reached even if there is a tendency to press the finger, and the time during which the sensor and the finger are in close contact with each other is maintained to some extent. For this reason, an unstable contact state between the finger and the so-called chattering sensor is unlikely to occur, and a predetermined contact time can be obtained, so that the authentication accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

FIG. 3 is a diagram showing still another embodiment of the present invention.

FIG. 4 is a block diagram showing the internal configuration of the embodiment of the present invention.

FIG. 5 is a diagram cited for explaining the operation of the embodiment of the present invention.

FIG. 6 is a diagram cited for explaining the operation of the embodiment of the present invention.

FIG. 7 is a diagram cited for explaining the operation of the embodiment of the present invention.

FIG. 8 is a diagram showing a calculation formula for realizing finger authentication.

[Explanation of symbols]

11 (21, 31) ... metal plate electrode (finger sensor), 12
(22, 32) cushioning material, 13 (23, 33) structure, 41 metal plate electrode, 42 analog switch, 43
... low-voltage power supply, 44 ... reference resistor, 45 ... sample and hold circuit, 46 ... A / D converter circuit, 47 ... timing pulse generator, 71 ... information equipment, 72 ... finger authentication device,
73 ... Authentication control unit.

Claims (6)

[Claims] A plurality of metal electrode plates long in a direction perpendicular to the longitudinal direction of a finger are arranged in a longitudinal direction of the finger, and when a finger is pressed against the group of metal electrode plates, a resistance or a capacitance between adjacent electrodes is set. In a finger authentication sensor for performing finger authentication by sensing a finger, a mechanism for generating a reaction force when a finger is pressed against each metal electrode plate is added, and the metal electrode plate has a movable structure. Mounting structure. 2. A metal plate electrode, a buffer material on which a plurality of the metal plate electrodes are mounted, and one end in the longitudinal direction of the buffer material is pivotally supported so as to be rotatable about its axis, 2. The mounting structure for a finger authentication sensor according to claim 1, further comprising a structure for generating a reaction force with the axis of the buffer material as a fulcrum when the finger is pressed against the metal electrode plate. 3. The mounting structure of a finger authentication sensor according to claim 1, wherein a spring is used as a mechanism for generating a reaction force against pressing of a finger. 4. The mounting structure for a finger authentication sensor according to claim 1, wherein a magnet is used as a mechanism for generating a reaction force against pressing of a finger. 5. The mechanism according to claim 1, wherein a viscous resistor that generates a reaction force in accordance with a pressure obtained by pressing the finger is used as a mechanism that generates a reaction force when the finger is pressed. Mounting structure of finger authentication sensor. 6. A metal electrode plate array in which a plurality of metal plate electrodes are arranged in a direction orthogonal to the longitudinal direction of a finger, and a force against a pressing stroke is generated by a reaction force generated by pressing a finger against the metal electrode plate array. A finger authentication sensor comprising: a reaction force generating mechanism that maintains balance; and a data sampling circuit that samples resistance or capacitance data between adjacent electrodes at a certain pressing stroke position.