JP2005160846A - Sweep type fingerprint input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and inexpensive sweep type fingerprint input device with reliable performance for fingerprint input. <P>SOLUTION: The fingerprint input device is equipped with a box body 3 having an opening 31 on the surface, a fingerprint sensor face 21 for reading a fingerprint image of moving finger 1 while it is made abut on fingerprint sensor surface 21 exposed to the opening 31, and a sensor table 4a for supporting the fingerprint sensor 2 so that the direction of the fingerprint sensor 2 can be changed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sweep type fingerprint input device, and more particularly to a support structure for a fingerprint sensor of a sweep type fingerprint input device.

  Conventionally, in many fingerprint input devices, a surface sensor that reads an entire image of a fingerprint is used, but in recent years, a sweep type fingerprint sensor that has a smaller mounting area and a lower price than a surface sensor has been used. (For example, refer to Patent Document 1). For example, as a part of the security function of a mobile phone, the sweep-type fingerprint sensor is used for an application in which a fingerprint sensor is installed in a mobile phone and a fingerprint is input instead of password input (for example, Patent Document 2). reference.).

  A sweep-type fingerprint input device usually uses a one-dimensional line-type sensor. In order to obtain a whole image of a fingerprint by reconstructing a plurality of partial fingerprint images, the input person moves a finger while moving the finger. A line-shaped fingerprint image is acquired. However, the input by the movement of the finger, especially when the input person is unfamiliar, the movement speed of the finger of the input person, the degree of force applied to the fingerprint sensor, the contact area between the finger surface and the fingerprint sensor surface, etc. are not constant, The quality of the obtained fingerprint image may be inferior to that of the surface sensor. Therefore, a method for further improving the reliability of fingerprint input in a sweep type fingerprint sensor has been disclosed.

  For example, a method is disclosed in which a transparent rotating roller that can be rotated by exposing a part of the outer peripheral surface from a slit provided in a housing is provided, and a SELFOC lens, a one-dimensional imaging device, and a light source are provided below the rotating roller. (For example, refer to Patent Document 3). In addition, a method is disclosed in which two lines of one-dimensional sensors are provided in the finger sweep direction to correct the deformation of the fingerprint image due to a change in finger movement speed (see, for example, Patent Document 4).

  On the other hand, in a fingerprint input device employing a surface sensor, a method for improving the reliability of fingerprint input by improving the adhesion of the finger to the sensor by causing the sensor to follow the direction of the finger is also disclosed. Yes.

For example, a housing, a hole provided in the housing, a support member attached to the periphery of the hole, and a fingerprint sensor having a fingerprint sensor surface on the outer surface and rotatably attached to the support member A fingerprint input device is disclosed in which the fingerprint sensor surface is flush with the outer surface of the housing (see, for example, Patent Document 5). Also, when the input person puts his finger on the fingerprint sensor surface of the fingerprint sensor, the follower mechanism composed of a spring or the like expands and contracts due to the finger pressure, the body rotates, and the finger rotates at a certain angle to the fingerprint sensor surface. A fingerprint input device that can be applied is disclosed (for example, see Patent Document 6).
JP-A-63-273976 JP 2003-157429 A JP 2002-133402 A JP 2002-216116 A JP 2003-70769 A JP 2000-293669 A

  However, in the conventional sweep type fingerprint input device, as in Patent Documents 1 to 4, the fingerprint sensor is fixed at a fixed angle with respect to the device. It is difficult to follow the finger surface shape which is an elastic surface. For this reason, there is a problem that there is a gap between the finger surface and the fingerprint sensor surface depending on the surface shape of the finger, and the contact area becomes small, so that a good fingerprint image cannot be obtained.

  On the other hand, the fingerprint input device adopting the surface sensor is easy to ensure the followability of the fingerprint sensor with respect to the movement of the finger as in the prior arts disclosed in Patent Documents 5 and 6, but the stroke for pushing the finger is large, the spring, etc. The required mechanism in the thickness direction of the housing is large, such as a complicated follow-up mechanism composed of the above, and there has been a problem in installation space when applied to a small terminal such as a mobile phone. In addition, when it is applied to a small terminal, it is required to be simple and inexpensive, and the conventional sweep type fingerprint sensor is not sufficient in this respect.

  In view of the above situation, an object of the present invention is to provide a sweep type fingerprint input device that is compact and inexpensive and has high reliability for fingerprint input.

  A sweep type fingerprint input device of the present invention includes a housing having an opening on the surface, a fingerprint sensor that reads a fingerprint image of a finger that moves while being in contact with a fingerprint sensor surface exposed to the opening, and a fingerprint sensor. And a sensor base that supports the orientation of the sensor in a changeable manner.

  Thus, when the fingerprint is input, the contact angle of the contact surface between the finger and the fingerprint sensor is automatically adjusted, so that the fingerprint sensor can obtain a good fingerprint image.

  The sweep type fingerprint input device according to the present invention has a support base provided inside the opening, one end fixed to the sensor base and the other end fixed to the support base, and orthogonal to the direction of finger movement in a plane parallel to the support base. And an elastic member that gives a rotational reaction force around the axis to be rotated.

  The elastic member is a coil spring in which both ends extend linearly and a shaft is inserted therein.

  The sweep type fingerprint input device of the present invention includes a support base provided in the opening, a ball joint fixed to the opposite surface of the sensor base to the fingerprint sensor surface and rotatably supporting the sensor base, and one end of the support base. The other end is fixed to the ball joint, and can be configured to further include an elastic member that applies a compression reaction force in a substantially vertical direction of the support base.

  The elastic member is a coil spring having a shaft inserted therein.

  The sweep type fingerprint input device of the present invention is configured to further include a support base provided in the opening and having a substantially semicircular cross-sectional protrusion extending in a direction perpendicular to the finger moving direction on the surface facing the sensor base. can do. The sensor base has a groove on the surface facing the protrusion, and the sensor base is rotatably supported by the support base by fitting the protrusion into the groove.

  The sweep type fingerprint input device of the present invention is provided on both sides of the sensor base along the direction of finger movement, with a support base provided inside the opening, one end fixed to the sensor base and the other end fixed to the support base. The sensor base can be configured to further include a plurality of ball joints that are rotatably supported by joint portions with the sensor base. In this case, the sensor base is formed of an elastic member, and the fingerprint sensor is formed by disposing a sensor element that reads a fingerprint image on a deformable sheet.

  As described above, according to the sweep type fingerprint input device of the present invention, the orientation of the fingerprint sensor surface is automatically adjusted according to the movement and shape of the finger of the input person, and the finger surface and the fingerprint sensor surface are separated. Since the contact can be made with a uniform and constant pressing force and a sufficient contact area can be secured, a good fingerprint image can be obtained.

  In addition, since the structure is compact, it can be easily applied to a small portable terminal such as a mobile phone without any problem in installation space. Furthermore, since it has a simple structure, it has the advantages of high reliability and low cost.

  A first embodiment of the sweep type fingerprint input device of the present invention will be described with reference to FIG. FIG. 1 shows a side view of a sweep type fingerprint input device.

  An opening 31 is provided on a part of the surface of the housing 3, and a support base 7 a is provided below the opening 31. The support base 7a is fixed to the housing 3 or an internal structure (not shown). The support base 7a may be a part of the housing 3.

  A torsion spring 6 is fixed on the support base 7a. Here, the torsion spring 6 means a coil spring in which both ends extend linearly. One end of the torsion spring 6 is fixed to the support base 7a, and the other end is fixed to the sensor base 4a (described later). The torsion spring 6 generates a predetermined rotational reaction force determined by a spring diameter, a thickness, and the like around an axis orthogonal to the moving direction of the finger 1 in a plane parallel to the support base 7a. As a result, a force that pushes the sensor base 4 a toward the surface of the finger 1 is applied, and the contact angle with the finger 1 is automatically adjusted according to the surface shape of the finger 1. Further, the shaft 5 maintains the shape of the torsion spring 6 so that the torsion spring 6 is not deformed, and ensures the rotational reaction force of the torsion spring 6. The torsion spring 6 is merely an example, and the torsion spring 6 is not limited to this as long as the rotational reaction force can be reliably generated between the support base 7a and the sensor base 4a. For example, it is possible to use a belt-like plate bent into a U shape.

  The other end of the torsion spring 6 is fixed to the sensor base 4a. The sensor base 4 a supports the fingerprint sensor 2 so that the fingerprint surface of the finger 1 of the input person can come into contact with the fingerprint sensor 2. A fingerprint sensor surface 21 that is a finger pressing surface of the fingerprint sensor is exposed to the outside of the housing 3 through the opening 31. The fingerprint sensor 2 is a sweep type fingerprint sensor that reads a partial fingerprint image, and is connected to a CPU (not shown) and a memory unit (not shown) via an input / output port (not shown) by wiring. . The acquired fingerprint image is appropriately subjected to image processing by these circuits. When the fingerprint sensor 2 is not used, a lock mechanism may be provided as appropriate so that the fingerprint sensor surface 21 does not protrude from the surface of the housing 3 so as to be flush with the surface of the housing 3.

  Next, the operation of the sweep type fingerprint input device will be described. The input person moves the finger 1 in contact with the fingerprint sensor surface 21 in the direction of the arrow in FIG. When a command to start fingerprint input is given to the sweep type fingerprint input device in advance, or when it is detected that the sensor base 4a is lowered to a predetermined position by pressing the finger 1, the fingerprint sensor 2 is synchronized with the movement of the finger 1 of the input person. Then, acquisition of partial fingerprint images is started. At this time, the fingerprint sensor 2 and the sensor base 4 a can move in a direction perpendicular to the surface of the finger 1 by the rotational reaction force of the torsion spring 6, so that the contact angle of the fingerprint sensor surface 21 is the surface shape of the finger 1. Follow and automatically adjust. Thereby, when acquiring a fingerprint image, the fingerprint sensor 2 can secure a sufficient contact area with the finger 1 and can obtain a good fingerprint image.

  As described above, the sweep-type fingerprint input device according to the present embodiment can improve the reliability of fingerprint image acquisition because the fingerprint sensor 2 can easily follow the movement of the finger 1, and can shorten the time. It is possible to acquire fingerprint images at the same time, which improves usability. Further, since the structure is simple, there is little risk of failure, and the torsion spring 6 can be easily replaced even if the rotational reaction force of the torsion spring 6 decreases with use. Furthermore, since it is inexpensive and excellent in space saving, it can be easily mounted on a small terminal such as a mobile phone.

  In addition to the above configuration, a damper can be provided along the torsion spring 6. The damper has an effect of suppressing the recovery of the torsion spring 6 when the finger 1 is released, and can prevent a sudden movement of the torsion spring 6.

  Next, a second embodiment of the sweep type fingerprint input device of the present invention will be described with reference to FIG. FIG. 2 shows a side view of the sweep type fingerprint input device. The mechanism for adjusting the contact angle of the fingerprint sensor in accordance with the surface of the finger is different from that of the first embodiment.

  Since the configurations of the housing 3, the support 7b, and the fingerprint sensor 2 are the same as those in the first embodiment, the following description will focus on the different parts. One end of a spring 9 made of a coil spring is supported on the support base 7b, and the other end of the spring 9 is fixed to the ball joint 8b. The ball joint 8b rotatably supports the sensor base 4b. The spring 9 is set in a direction in which a compressive force is generated in the pushing direction of the finger 1, that is, in the substantially vertical direction of the support base 7b. A movable shaft (not shown) for holding the shape of the spring 9 is inserted into the spring 9. The movable shaft includes, for example, an outer cylinder having a hollow portion with a predetermined inner diameter and an inner cylinder having an outer diameter smaller than the diameter of the hollow portion of the outer cylinder, and the inner cylinder is inserted into the outer cylinder in accordance with the expansion and contraction of the spring 9. The shape of the spring 9 is held while following the length of the spring 9.

  Thus, by providing the spring 9 and the ball joint 8b, when the finger 1 is moved in the direction of the arrow in FIG. 2 to input a fingerprint, the spring 9 absorbs the movement of the finger 1 in the pushing direction, and the finger 1 The ball joint 8b absorbs the movement in the rotation direction. That is, the fingerprint sensor 2 and the sensor base 4b are pressed against the surface of the finger 1 with a predetermined force by the spring 9, and the contact angle is automatically adjusted by the ball joint 8b, so that the fingerprint sensor 2 is always parallel to the surface of the finger 1. become. In this way, the fingerprint sensor 2 is in contact with the surface of the finger 1 with a uniform and constant pressing force, and a sufficient contact area can be secured, and a good fingerprint image can be obtained.

  The spring 9 is not limited to a coil spring as long as a predetermined vertical reaction force can be generated in the pressing direction of the finger 1. For example, an air spring filled with air or an elastic material such as urethane can be used.

  Next, a third embodiment of the sweep type fingerprint input device of the present invention will be described with reference to FIG. FIG. 3 shows a side view of the sweep type fingerprint input device. The mechanism for adjusting the contact angle of the fingerprint sensor in accordance with the surface of the finger 1 is different from the first and second embodiments.

  The support table 7c has an inclined fulcrum 71 on the surface facing the sensor table 4c. The inclined fulcrum 71 is a protrusion having a substantially semicircular cross section provided inside the opening of the housing 3 and extending in a direction orthogonal to the moving direction of the finger 1 (indicated by an arrow in FIG. 3) on the surface facing the sensor base 4c. is there. An inclined fulcrum support 41 is provided on the surface of the sensor base 4c that faces the inclined fulcrum 71c. The inclined fulcrum support 41 is a groove fitted to the inclined fulcrum 71. A fingerprint sensor 2 is attached to the sensor base 4c.

  When the finger 1 is moved in the direction of the arrow in FIG. 3 to input a fingerprint, the sensor base 4c can freely move in the rotation direction around the tilt fulcrum 71 of the support base 7c. For this reason, the force that the finger 1 receives from the surface of the fingerprint sensor 2 is made uniform, and the contact angle between the finger 1 and the fingerprint sensor 2 is automatically adjusted in the direction in which the contact area between the finger 1 and the fingerprint sensor 2 increases. The sensor 2 can obtain a good fingerprint image.

  In the present embodiment, the inclined fulcrum 71 does not have to be a semicircular cross-sectional protrusion, and may be, for example, a hemispherical protrusion. In this case, the inclined fulcrum support fitted into the protrusion is a hemispherical recess. With such a configuration, the contact angle between the finger 1 and the fingerprint sensor 2 is automatically adjusted not only in the moving direction of the finger 1 but also in the direction orthogonal to the moving direction, so that the fingerprint sensor 2 produces a good fingerprint image. Can be obtained.

  This embodiment does not require a member such as a spring, and only needs a rotation fulcrum and its fulcrum support, which is further advantageous in terms of space saving, and further improves the mounting property to a mobile phone or the like.

  In the first to third embodiments described above, the finger 1 is described as moving along the line connecting the base of the finger 1 and the tip, but the moving direction of the finger 1 may be a direction orthogonal to this. Good. An embodiment in this case is shown in FIG. FIG. 4 shows a side view of the sweep-type fingerprint input device in the second embodiment when the direction of movement of the finger 1 is perpendicular to the line connecting the base of the finger 1 and the tip. The configuration of the embodiment is the same as that of the second embodiment. Of course, the first and third embodiments can be similarly configured.

  Next, a fourth embodiment of the sweep type fingerprint input device of the present invention will be described with reference to FIG. FIG. 5 shows a side view of the sweep type fingerprint input device. The difference from the first to third embodiments is that the shape of the fingerprint sensor and the sensor base itself is changed and followed according to the shape of the finger.

  An opening 31 is provided on a part of the surface of the housing 3, and a support base 7 e is provided below the opening 31. A ball joint 8e is provided at a substantially symmetric position with respect to a center line parallel to the moving direction of the finger 1 of the support base 7e. A plurality of ball joints 8e may be provided along the moving direction of the finger 1. The ball joint 8e has the same structure as the ball joint 8b described in the second embodiment, and supports the sensor base 4e without giving a resistance moment to the sensor base 4e even if the sensor base 4e (described later) is deformed. Secure to the base 7e.

  A sensor base 4e is supported on the ball joint 8e. The sensor base 4 e is configured by an elastic member that can be deformed following the shape of the finger 1 by a pressing force received from the finger 1.

  A fingerprint sensor 2e is fixed to the sensor base 4e. The fingerprint sensor 2e is formed by disposing a sensor element that reads a fingerprint image on a deformable sheet. Specifically, it is formed of a material that can read a partial fingerprint image while elastically deforming following the shape of the finger 1 by a pressing force received from the finger 1, for example, an FPC (Flexible Printed Circuit).

  When the finger 1 is moved in the direction of the arrow in FIG. 5 (a direction parallel to the direction from the base of the finger 1 to the fingertip) and a fingerprint is input, the sensor base 4e is orthogonal to the moving direction due to the force received from the surface of the finger 1 The finger surface is elastically deformed following the finger surface shape (cross-sectional shape of the finger). Thereby, the contact area between the finger 1 and the fingerprint sensor 2 becomes larger than when the sensor base is not deformed, and the fingerprint sensor 2 can obtain a good fingerprint image.

  Here, the finger 1 has been described as moving along a line connecting the base of the finger 1 and the tip, but the moving direction of the finger 1 may be a direction orthogonal thereto.

  In addition, the present embodiment follows the surface shape of the finger 1 on the surface orthogonal to the moving direction of the finger 1, but in combination with the first to third embodiments, the surface shape of the finger 1 in the direction parallel to the moving direction is obtained. May be followed simultaneously.

1 is a side view of a sweep type fingerprint input device according to a first embodiment of the present invention. It is a side view of the sweep type fingerprint input device according to the second embodiment of the present invention. It is a side view of the sweep type fingerprint input device according to the third embodiment of the present invention. It is a side view of the sweep type fingerprint input device when the moving direction of the finger is different in the second embodiment of the present invention. It is a side view of the sweep type fingerprint input device according to the fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Finger 2, 2e Fingerprint sensor 21 Fingerprint sensor surface 3 Case 31 Opening 4a, 4b, 4c, 4d, 4e Sensor base 41 Inclined fulcrum support 5 Shaft 6 Torsion spring 7a, 7b, 7c, 7d, 7e Support base 71 Inclined fulcrum 8b, 8d, 8e Ball joint 9 Spring

Claims (7)

A housing having an opening on the surface;
A fingerprint sensor that reads a fingerprint image of a finger that moves while being in contact with the fingerprint sensor surface exposed in the opening;
A fingerprint input device comprising: a sensor base that supports the fingerprint sensor so that the orientation of the fingerprint sensor can be changed. A support provided inside the opening;
An elastic member that has one end fixed to the sensor base and the other end fixed to the support base, and applies a rotational reaction force around an axis orthogonal to the moving direction of the finger in a plane parallel to the support base; The fingerprint input device according to claim 1.   The fingerprint input device according to claim 2, wherein the elastic member is a coil spring in which both ends extend linearly and a shaft is inserted therein. A support provided inside the opening;
A ball joint fixed to the surface of the sensor table opposite to the fingerprint sensor surface and rotatably supporting the sensor table;
The fingerprint input device according to claim 1, further comprising: an elastic member having one end fixed to the support base and the other end fixed to the ball joint, and applying a compression reaction force in a substantially vertical direction of the support base.   The fingerprint input device according to claim 4, wherein the elastic member is a coil spring having a shaft inserted therein. A support base having a substantially semicircular cross-sectional protrusion provided on the surface facing the sensor base and extending in a direction perpendicular to the direction of movement of the finger;
The sensor base has a groove on a surface facing the protrusion,
The fingerprint input device according to claim 1, wherein the sensor table is rotatably supported by the support table by fitting the protrusion into the groove. A support provided inside the opening;
Provided on both sides of the sensor base along the direction of movement of the finger, one end is fixed to the sensor base and the other end is fixed to the support base, and the sensor base can be rotated at the joint with the sensor base. A plurality of supporting ball joints;
The sensor base is formed by an elastic member,
The fingerprint input device according to claim 1, wherein the fingerprint sensor is formed by disposing a sensor element that reads a fingerprint image on a deformable sheet.

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