JP2011258015A - Vein authentication apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vein authentication apparatus capable of enhancing authentication accuracy by detecting the state of a finger placed thereon.SOLUTION: The vein authentication apparatus according to the invention comprises: plural placement detection sections each disposed on a predetermined substrate for detecting if a part of a finger is placed thereon; plural light source sections each disposed on the substrate for emitting near-infrared light of a predetermined wavelength to a part of the placed finger; and an imaging section for taking an image of the part of the finger illuminated by the near-infrared light. When the substrate is viewed from a direction perpendicular to a longitudinal direction of the finger, the light source section and the placement detection section are disposed alternately on the substrate along the longitudinal direction of the finger.

Description

  The present invention relates to a vein authentication device.

  Biometric personal identification is a very important technology for protecting the rights in the future network society. In particular, in commercial transactions on the Internet, where other people can impersonate themselves and steal money, content, rights, etc. over the Internet, they are attracting attention as a technology that protects areas that cannot be solved by encryption alone. However, fingerprints and irises cannot solve the problem of forgery. In this regard, personal authentication technology using a part that cannot be easily imaged from the outside with a vein pattern is expected as next-generation biometric personal authentication because of its high accuracy of determination, forgery, and impersonation.

  In particular, finger vein authentication focusing on the vein pattern existing inside the finger has an advantage that the authentication device can be made smaller than palm vein authentication focusing on the vein pattern existing inside the palm. However, in recent years, with the spread of various mobile devices such as mobile devices using mobile phones and touch panels, finger vein authentication devices are required to be further reduced in size and thickness. Therefore, in the following Patent Document 1, a technique for realizing a reduction in size and thickness of a finger vein authentication device is disclosed.

JP 2009-98935 A

  By the way, as a result of the present inventor's earnest examination regarding a series of flows of finger vein authentication processing, when performing an operation of placing one finger on a certain plane, the operation is performed without being conscious of it. I came up with the point that the fingers are often not in contact with the plane. In other words, when viewed from the target plane, the distance between the plane and the finger is often not substantially constant when the user does not consider the operation of placing the finger. .

  In the finger vein authentication device as described in Patent Document 1, when the distance between the light source that emits near-infrared light and the finger is not substantially constant, the authentication accuracy of the finger vein authentication process decreases. There was a problem of inviting.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a vein that can further improve authentication accuracy by detecting the placement state of a finger. It is to provide an authentication device.

  In order to solve the above-described problem, according to an aspect of the present invention, a plurality of placement detection units disposed on a predetermined substrate for detecting whether or not a part of a finger is placed, and a placement A plurality of light source units disposed on the substrate for irradiating a part of the placed finger with near-infrared light of a predetermined wavelength; and a part of the finger irradiated with the near-infrared light And when the substrate is viewed from a direction orthogonal to the longitudinal direction of the finger, the light source unit and the placement detection unit are arranged along the longitudinal direction of the finger. A vein authentication device is provided that is alternately disposed above.

  A resin layer that covers the plurality of placement detection units and the plurality of light source units is further provided, and the surface on the side where the placement detection unit and the light source unit do not exist in the thickness direction of the resin layer are flat, It is preferable that a part of a finger is placed on the flat surface of the resin layer.

  It is preferable that the plurality of light source units start irradiation of the near-infrared light when all the placement detection units detect placement of a finger.

  An interval between the light source units adjacent to each other along the longitudinal direction of the finger may become wider toward the side where the fingertip is placed.

  The number of the light source units arranged along the longitudinal direction of the finger is arranged in a direction perpendicular to the longitudinal direction of the finger as the position of the finger in the longitudinal direction is closer to the base of the finger. May be increased.

  The plurality of placement detection units are arranged in a line along the longitudinal direction of the finger, and the plurality of light source units are parallel to the row on both sides of the row of the plurality of placement detection units. It may be arranged so that.

  The placement detection unit and the light source unit are arranged in a line along the longitudinal direction of the finger, and a plurality of rows of placement detection units and light source units exist in parallel to each other. Also good.

  The imaging unit may be disposed between rows of the plurality of mounting detection units and light source units adjacent to each other.

  The plurality of placement detection units are preferably an electrostatic sensor, a photo sensor, a pressure sensor, or a Hall sensor.

  As described above, according to the present invention, it is possible to further improve the authentication accuracy by detecting the placement state of the finger.

It is explanatory drawing which showed the external appearance of the finger vein authentication apparatus which concerns on the 1st Embodiment of this invention. It is a top view at the time of seeing the finger vein authentication device concerning the embodiment from the upper part. It is sectional drawing which showed the cross section in the AA cutting line of FIG. It is explanatory drawing for demonstrating the resin layer which concerns on the same embodiment. It is explanatory drawing for demonstrating the mounting detection part which concerns on the same embodiment. It is explanatory drawing for demonstrating the mounting detection part which concerns on the same embodiment. It is explanatory drawing for demonstrating the mounting detection part which concerns on the same embodiment. It is explanatory drawing for demonstrating the mounting detection part which concerns on the same embodiment. It is explanatory drawing for demonstrating the mounting detection part which concerns on the same embodiment. It is explanatory drawing for demonstrating the mounting detection part which concerns on the same embodiment. It is explanatory drawing for demonstrating a captured image and a vein pattern. It is explanatory drawing which showed the 1st modification of the finger vein authentication apparatus which concerns on this embodiment. It is explanatory drawing which showed the 2nd modification of the finger vein authentication apparatus which concerns on this embodiment. It is explanatory drawing which showed the 3rd modification of the finger vein authentication apparatus which concerns on this embodiment.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The description will be made in the following order.
(1) 1st Embodiment (1-1) About structure of finger vein authentication apparatus (1-2) About sectional structure of finger vein authentication apparatus (1-3) About mounting detection part and light source part (1-4 ) Modification

(First embodiment)
<Configuration of finger vein authentication device>
First, the configuration of the finger vein authentication device 1 according to the embodiment of the present invention will be briefly described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram showing the appearance of the finger vein authentication device according to the present embodiment, and FIG. 2 is a top view when the finger vein authentication device according to the present embodiment is viewed from above.

  As illustrated in FIG. 1, the finger vein authentication device 1 according to the present embodiment includes a housing on which a part of a user's finger F is placed, and an imaging unit 101 provided in the housing. This casing may be printed to indicate the position (placement position) where the user places the finger, or may be displayed to indicate the placement position of the finger.

  In addition, as shown in FIG. 2, a plurality of placement detection units 103 and a plurality of light source units 105 are disposed in the casing of the finger vein authentication device 1 along the long axis direction of the finger. Yes. Further, a resin layer 107 is provided at least at a position where the finger is placed in the casing of the finger vein authentication device 1, and the resin layer 107 allows a plurality of placement detection units 103 and light source units 105 to be placed. Is covered.

  When the user places the finger F on the placement position of the finger vein authentication device 1, each of the plurality of placement detection units 103 detects whether or not the finger is placed and outputs a detection result. A control unit (not shown) provided in the finger vein authentication device 1 refers to the detection result output from each placement detection unit 103, and has satisfied the imaging start condition described below again? Make a decision. When the imaging start condition is satisfied, the control unit requests the plurality of light source units 105 to start irradiation of near infrared light having a predetermined wavelength and requests the imaging unit 101 to start imaging of the finger. To do. Further, the control unit extracts a vein pattern from the captured image of the finger imaged by the imaging unit 101, and performs user authentication based on the extracted vein pattern.

  Here, the control unit provided in the finger vein authentication device 1 will be briefly described. The control unit is realized by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication device, and the like. The control unit controls the overall operation of the finger vein authentication device 1 using various programs, parameters, databases, and the like stored in a storage unit (not shown) provided in the finger vein authentication device 1. In addition, the user's finger vein authentication process is performed.

The imaging unit 101 includes an optical element such as a lens and an imaging element.
It is known that the human skin has a three-layer structure of an epidermis layer, a dermis layer, and a subcutaneous tissue layer, but a vein layer in which a vein exists exists in the dermis layer. The dermis layer is a layer present at a thickness of about 2 mm to 3 mm from a position of about 0.1 mm to 0.3 mm with respect to the finger surface. Therefore, by setting the focal position of an optical element such as a lens at the position where such a dermis layer is present (for example, a position of about 1.5 mm to 2.0 mm from the finger surface), the transmitted light transmitted through the vein layer can be reduced. It is possible to collect light efficiently.

  The transmitted light that has passed through the vein layer collected by the optical element is imaged on an image sensor such as a CCD or CMOS to form a vein image. When generating the vein captured image, the imaging unit 101 outputs the generated vein captured image to the control unit.

  The placement detection unit 103 detects whether or not the user's finger F is placed. The placement detection unit 103 is preferably formed using, for example, an electrostatic sensor, a photo sensor, a pressure sensor, or a Hall sensor. These sensors can detect the placement of the finger as long as the user's finger F touches the sensor or another object (for example, the resin layer 107) in contact with the sensor.

  Although various contact switches can be used as the placement detection unit 103, when the user's finger presses the contact switch, the vein existing inside the finger is also compressed. The amount of blood flowing inside the veins can be reduced. As will be described below, in the finger vein authentication process, since the density of the vein image is determined according to the amount of near-infrared light absorbed by hemoglobin in the blood, it is not preferable that the blood flow rate decreases. . Therefore, it is preferable to use the above sensors rather than using a contact switch as the placement detection unit 103.

  The plurality of placement detection units 103 provided in the finger vein authentication device 1 are used for determining whether or not the user's finger is placed at an appropriate position, as will be described below. At the same time, the light source unit 105 described later is also used as a switch for irradiating near infrared light.

  When the plurality of placement detection units 103 provided in the finger vein authentication device 1 detect that the user's finger is placed, the plurality of placement detection units 103 output the detection result to the control unit. The control unit emits near-infrared light from the light source unit 105 when a detection result indicating that the placement of the finger has been detected is obtained from all the placement detection units 103 provided in the finger vein authentication device 1. At the same time, the imaging of the finger by the imaging unit 101 is started.

  The light source unit 105 irradiates the user's finger F placed on the finger vein authentication device 1 with near infrared light having a predetermined wavelength. The light source unit 105 may be, for example, a light emitting diode capable of irradiating near infrared light, a light emitting element that emits light of a predetermined wavelength, and a filter that converts light from the light emitting element into near infrared light. The unit comprised from may be sufficient.

  Here, the timing at which the light source unit 105 starts irradiating near-infrared light to the user's finger is when all the placement detection units 103 provided in the finger vein authentication device 1 detect the finger. Is preferred. By starting near-infrared light irradiation at such timing, it is not necessary to always irradiate near-infrared light, and the power consumption of the finger vein authentication device 1 can be suppressed.

  Near-infrared light is highly permeable to body tissues, but is absorbed by hemoglobin in the blood (reduced hemoglobin), so when irradiating near-infrared light on the fingers, palms and back of the hand, The veins distributed inside the fingers, palms and back of the hand appear in the image as shadows. The shadow of the vein that appears in the image is called the vein pattern. In order to image such a vein pattern satisfactorily, the light source unit 105 such as a light emitting diode irradiates near infrared light having a wavelength of about 600 nm to 1300 nm, preferably about 700 nm to 900 nm.

  Here, when the wavelength of near-infrared light emitted by the light source unit 105 is less than 600 nm or more than 1300 nm, the proportion absorbed by hemoglobin in the blood is small, and it is difficult to obtain a good vein pattern. It becomes. Further, when the wavelength of the near infrared light emitted from the light source unit 105 is about 700 nm to 900 nm, the near infrared light is specifically absorbed by both deoxygenated hemoglobin and oxygenated hemoglobin. Therefore, a good vein pattern can be obtained.

  Near-infrared light emitted from the light source unit 105 propagates toward the surface of the living body part, and enters the living body from the finger surface or the like as direct light. Here, since the human body is a good scatterer of near-infrared light, the direct light entering the living body propagates while being scattered in all directions. Near-infrared light transmitted through the living body is collected by the imaging unit 101 and becomes a vein image.

  The resin layer 107 is a layer formed of a material that can transmit near-infrared light, and may be a near-infrared light transmission filter that transmits near-infrared light. The material used for forming the resin layer 107 is not particularly limited as long as it transmits near-infrared light, and any material can be used.

  As will be described below, the resin layer 107 is formed so as to cover the placement detection unit 103 and the light source unit 105. In other words, it can be said that the resin layer 107 is a resin mold.

  The configuration of the finger vein authentication device 1 has been briefly described above with reference to FIGS. 1 and 2, but the placement detection unit 103, the light source unit 105, and the resin layer 107 will be described again in detail below.

<About the cross-sectional structure of the finger vein authentication device>
Next, a cross-sectional structure of the finger vein authentication device 1 will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a cross section when the finger vein authentication device 1 shown in FIG. 2 is cut along an AA cutting line.

  When the finger vein authentication device 1 according to the present embodiment is cut along the AA cutting line in FIG. 2 and viewed from a direction orthogonal to the finger major axis direction, a plurality of placements are provided as shown in FIG. The detection unit 103 and the light source unit 105 are alternately arranged along the finger long axis direction. Further, as shown in FIG. 3, the plurality of placement detection units 103 and the light source unit 105 are mounted on the same surface of the substrate 11.

  The substrate 11 can be made of any material as long as the placement detection unit 103 and the light source unit 105 can be placed thereon. In addition, wiring or the like for realizing exchange of information between the placement detection unit 103 and the light source unit 105 and a control unit (not shown) may be printed on the substrate 11.

  In addition, various sensors used as the placement detection unit 103 and various light-emitting diodes used as the light source unit 105 often have different heights as illustrated in FIG. In the finger vein authentication device 1 according to the present embodiment, the resin layer 107 is formed so as to cover the placement detection unit 103 and the light source unit 105, and the placement detection unit 103 and the light source unit in the thickness direction of the resin layer 107. The surface on the side where 105 does not exist is a flat surface as shown in FIG. The user's finger is placed on the flat surface.

  FIG. 4 is a schematic view showing a part of the resin layer 107 in an enlarged manner. As shown in FIG. 4, concave portions 109 and 111 corresponding to the shapes of the placement detection unit 103 and the light source unit 105 are formed on the surface of the resin layer 107 facing the placement detection unit 103 and the light source unit 105. Yes. In the example illustrated in FIG. 4, the placement detection unit 103 is accommodated in the recess 109, and the light source unit 105 is accommodated in the recess 111. Since the placement detection unit 103 and the light source unit 105 are accommodated in the corresponding recesses, the thickness of the unit including the placement detection unit 103, the light source unit 105, and the resin layer 107 can be reduced, and the unit can be downsized. This can be realized, and the finger placement surface can be made flat. In addition, since the finger placement surface is realized as a flat surface, there is no restriction on the place where the unit including the placement detection unit 103, the light source unit 105, and the resin layer 107 is attached.

  A difference ΔD in the depth of the recess 109 with respect to the depth of the recess 111 is a difference between the height of the placement detection unit 103 and the height of the light source unit 105. By adjusting the depth of the concave portion 111, it is possible to adjust the distance from the bottom surface of the concave portion 111 to the flat surface of the resin layer 107 on which the finger is placed. It is possible to adjust the amount of light. What is necessary is just to adjust the depth of the recessed part 111 suitably so that the light quantity of near-infrared light suitable for the production | generation of a vein imaging image may be implement | achieved.

  In addition, since the light source unit 105 is accommodated in the recess 111, the distance between the light source unit 105 and the finger placed on the flat surface is shortened, and the near infrared light transmission efficiency can be improved. . As a result, even with a low-output light emitting diode, it is possible to increase the amount of near-infrared light emitted to the finger, so that a clearer vein image can be obtained. Moreover, the fact that a low-power (that is, a small-sized) light-emitting diode can be used means that the power consumption of the light source unit 105 can be reduced, and further, the device can be miniaturized. It becomes possible.

  Note that the size of the area where the placement detection unit 103 and the light source unit 105 are provided (in other words, the length L in FIG. 3) can be determined with reference to the length of a general human finger. Well, not particularly limited.

<About the placement detection unit and the light source unit>
Next, the number of placement detectors 103 provided in the finger vein authentication device 1 according to the present embodiment will be described with reference to FIGS. 5A to 7B. 5A to 7B are explanatory diagrams for explaining the placement detection unit. 5A to 7B illustrate the placement detection unit 103, and the light source unit 105 is not illustrated.

  As shown in FIG. 5A, consider a case where two placement detectors 103 are provided in the finger vein authentication device 1. In such a case, although depending on the position where the two placement detectors 103 are installed, when the placement detector 103 is provided as shown in FIG. 5A, the user's finger F placed is shown in FIG. 5A. Even in such a case, the two placement detectors 103 detect the finger F. In this case, when the imaging unit 101 located on the side of the finger F captures the finger F, the distance from the imaging unit 101 differs between the vicinity of the fingertip and the vicinity of the base of the finger. A large image is captured, and the vicinity of the base of the finger is imaged relatively small. Even when the same finger F is imaged, if there is a portion where the distance from the imaging unit 101 is large, it is difficult to accurately extract the vein pattern. Image processing such as enlargement / reduction processing must be performed. Therefore, it is preferable that the longitudinal direction of the finger F to be imaged is closer to the direction orthogonal to the optical axis direction.

  Therefore, it is preferable to provide three or more placement detectors 103 in the finger vein authentication device 1 to detect whether or not a finger is placed in the vicinity of the fingertip, the central portion of the finger, and the vicinity of the base of the finger, for example. . For example, as shown in FIG. 5B, when the placement detection unit 103 is provided and the finger F is placed obliquely, the placement detection unit 103 in the center portion detects the finger, The placement detection unit 103 located near the base of the finger does not detect the finger. As a result, when the finger F is placed obliquely, the conditions for starting the imaging are not satisfied, and the finger is not captured in a situation where the authentication accuracy may be reduced. Can be.

  In addition, when the placement detection unit 103 of a certain part detects a finger, but the other placement detection unit 103 does not detect the finger, the finger F may be placed diagonally. The control unit (not shown) may specify the position of the placement detection unit 103 that does not output that the finger has been detected. The control unit may display a message such as notifying the user that there is a position where the finger has not been detected based on the specified position of the placement detection unit 103 and having the finger placed again. . In this way, by guiding the user to the correct finger placement position, it is possible to generate an appropriate vein image more accurately, and thus improve the accuracy of authentication. .

  5B illustrates the case where three placement detection units 103 are provided in the finger vein authentication device 1, but four or more placement detection units 103 may be provided in the finger vein authentication device 1. This is because as the number of placement detection units 103 increases, the situation of the placed fingers can be grasped more accurately. In addition, regarding the number of placement detection units 103 mounted on the finger vein authentication device 1 and the distance (arrangement interval) between adjacent placement detection units 103, the length and shape of a typical human finger are considered. Then, it may be set as appropriate.

  As described above, when a person places his / her finger on a flat surface unconsciously with the belly of the finger down, as shown in FIG. 6A, a part of the finger does not touch the flat surface. Often floating. In this case, for example, when near-infrared light is irradiated from below the finger, the amount of near-infrared light irradiated to the floating portion is near-infrared light irradiated to the portion in contact with the flat surface. Therefore, the vein-captured image of the corresponding part becomes a dark image. As a result, it becomes difficult to extract an accurate vein pattern from the vein image of the corresponding part, and authentication accuracy may be reduced. In addition, when the imaging unit 101 captures a finger from the side surface of the finger, in the state illustrated in FIG. 6A, a vein captured image is generated with the finger bent, and thus the extracted vein pattern is In this case, the image frame is curved. Such a vein pattern state is expected to be greatly different from the shape of a vein pattern (registered vein pattern) that has been registered in advance and collated during authentication processing, which may lead to a decrease in authentication accuracy. There is sex.

  Therefore, for example, as shown in FIG. 6A, by providing a plurality (preferably three or more) of the placement detection units 103 in the finger vein authentication device 1, the placement detection unit 103 corresponding to a portion that is not in contact with the flat surface. Will not output that the finger has been detected. As a result, in the finger vein authentication device 1 according to the present embodiment, it is possible to accurately grasp the situation where a part of the finger as shown in FIG. 6A is not in contact with the flat surface.

  6B is a view of the finger vein authentication device 1 as viewed from above. As shown in FIG. 6B, the finger side surface is brought into contact with the finger placement position of the resin layer 107, and the finger A case where the stomach is imaged by the imaging unit 101 is also conceivable. In such a case, as shown in FIG. 6B, if the finger is placed at the finger placement position in a curved state, the amount of near infrared light as described above may be partially reduced. There may be a problem. Further, in the case shown in FIG. 6B, since the distance from the imaging unit 101 is different between the center portion of the finger and the tip portion and the base vicinity portion of the finger, the image size corresponding to the center portion of the finger corresponds to both end portions. There is a possibility that it becomes smaller than the image size. Since the vein pattern extracted from such a vein image is partially different in scale, authentication accuracy may be reduced. Therefore, in such a case, in order to make the scale of the entire image substantially the same, extra image processing is performed in which the vein image is partially enlarged or reduced.

  However, as shown in FIG. 6B, for example, by providing a plurality (preferably three or more) of the placement detection units 103 in the finger vein authentication device 1, the placement detection unit 103 corresponding to the curved portion is removed. The output indicating that the finger has been detected is not performed. As a result, in the finger vein authentication device 1 according to this embodiment, it is possible to accurately grasp the situation where the finger is in contact with the flat surface in a curved state as shown in FIG. 6B.

  As described above, in the finger vein authentication device 1 according to the present embodiment, it is possible to accurately determine whether the finger F is in contact with the flat surface of the resin layer 107 as shown in FIG. It is possible to judge. Similarly, in the finger vein authentication device 1 according to the present embodiment, as shown in FIG. 7B, whether the finger F is placed straight on the flat surface of the resin layer 107 (the optical axis direction of the imaging unit 101 and the finger length). It is possible to accurately determine whether or not the axial direction is substantially orthogonal.

  In the finger vein authentication device 1 according to the present embodiment, as described above, the light source unit 105 emits near-infrared light when all the placement detection units 103 output an output indicating that a finger has been detected. The imaging of the finger is started. In the state shown in FIGS. 7A and 7B, the distance between the placed finger F and the light source unit 105 is substantially the same, and the distance between the imaging unit 101 and the finger F is also substantially the same. It is thought that. By capturing an image of the finger F in such a state, it is possible to obtain a vein image that is suitable for finger vein authentication processing and, in turn, it is possible to further improve the authentication accuracy of the finger vein authentication processing.

  The number of placement detectors 103 provided in the finger vein authentication device 1 according to the present embodiment has been described above with specific examples.

  In addition, the number and position of the light source units 105 may be appropriately set according to the output of a light emitting diode used as the light source unit 105, the shape of a general human finger, or the like. For example, a plurality of light sources such as light emitting diodes may be arranged uniformly so that near-infrared light is evenly irradiated to the irradiation range of interest. In general, a human finger becomes thicker from the fingertip toward the base of the finger. Therefore, the interval between the light source parts adjacent along the finger major axis direction may be set so as to increase toward the side where the fingertip is placed.

  As described above, in the finger vein authentication device 1 according to the present embodiment, the placement detection unit 103 and the light source unit 105 are housed inside the resin layer 107 on which the finger F is placed. And the distance between the finger F can be shortened. Therefore, it is possible to generate a vein image with a smaller amount of near-infrared light than in the past. In addition, the fact that the distance between the light source unit 105 and the finger F is short also means that the finger F can be irradiated with more near infrared light.

  FIG. 8 is an explanatory diagram for explaining the relationship between the captured image and vein pattern and the amount of irradiated near-infrared light. When the amount of near-infrared light irradiated to the finger being imaged is small, the amount of near-infrared light diffusing inside the finger is reduced, so the obtained captured image is as shown on the left side of FIG. In addition, the image becomes dark. In the dark image, the difference between the position where the vein exists and the position where the vein does not exist is not clear, so that there is a high possibility that noise is present in the extracted vein pattern.

  On the other hand, when a near-infrared light having an appropriate amount of light is irradiated onto the finger that is the imaging target, it is possible to generate a bright vein captured image in which the vein portion is blackened as shown on the right side of FIG. . In such a bright vein image, a position where a vein is present and a position where no vein is present can be clearly distinguished as a difference in brightness (luminance value), so that a vein pattern is accurately extracted. be able to.

  The vein image shown in FIG. 8 is obtained by imaging the same finger by changing the amount of near infrared light to be irradiated. As can be seen from FIG. 8, the vein pattern extracted from the image irradiated with the appropriate amount of light and the vein pattern extracted from the captured image when the amount of light is small are greatly different in shape. .

  In addition, although FIG. 8 demonstrated the case where the light quantity of the near-infrared light irradiated was small, when the light quantity more than necessary was irradiated, it becomes difficult to extract an exact vein pattern. This is because when the amount of near-infrared light more than necessary is irradiated, the amount of light is saturated, and a white vein image is generated, and the luminance value between the position where the vein exists and the position where the vein does not exist This is because the difference between the two becomes smaller.

  The finger vein authentication device 1 according to the present embodiment has been described in detail above with reference to FIGS.

<Modification>
Next, a modified example of the finger vein authentication device 1 according to the present embodiment will be briefly described with reference to FIGS. 9A to 9C. 9A to 9C are explanatory diagrams illustrating modifications of the finger vein authentication device according to the present embodiment. 9A to 9C are diagrams when the finger vein authentication device according to each modification is viewed from above.

  In the example described above, the plurality of placement detection units 103 and the light source units 105 are alternately arranged in a line along the finger major axis direction. In the first modification of the finger vein authentication device 1 according to the present embodiment illustrated in FIG. 9A, a plurality of placement detection units 103 are arranged in a line along the placement position of the finger F. A row of light source units 105 including a plurality of light source units 105 is arranged on both sides of the row of detection units 103. In this case, whether or not the finger is placed is detected by the placement detection unit 103 located below the finger F, and near infrared light is emitted from the light source unit 105 located on the side of the finger F toward the finger F. It will be irradiated.

  9A, when the substrate 11 on which the placement detection unit 103 and the light source unit 105 are disposed is viewed from a direction orthogonal to the finger major axis direction, the placement detection unit 103 and the light source. The parts 105 are alternately arranged.

  In the case shown in FIG. 9A, each light source unit 105 may be adjusted so that the irradiation direction of the near-infrared light becomes the direction of the finger by being disposed obliquely with respect to the substrate 11. The finger F may be efficiently irradiated with near infrared light by using a light guide plate or the like.

  In the second modification of the finger vein authentication device 1 according to the present embodiment shown in FIG. 9B, attention is paid to the fact that a human finger becomes thicker toward the base of the finger, and the number of light source units 105 to be mounted is adjusted. It is. As described above, a human finger becomes thicker toward the base of the finger, and as the thickness increases, the possibility that near-infrared light passes through the finger becomes lower. For this reason, there is a possibility that the amount of light required to generate a vein image is insufficient at a site where the finger is thick.

  Therefore, in the second modification shown in FIG. 9B, the light source unit disposed along the finger long axis direction has a larger distance from the finger long axis direction as the position in the finger long axis direction is closer to the base of the finger. Thus, the number arranged in the orthogonal direction increases. That is, in the example shown in FIG. 9B, only one light source unit 105 is disposed in the vicinity of the fingertip, but two light source units 105 are disposed side by side in the central portion of the finger. In the region near the base of the finger, three light source sections 105 are arranged side by side.

  9B, when the substrate 11 on which the placement detection unit 103 and the light source unit 105 are disposed is viewed from a direction orthogonal to the finger major axis direction, the placement detection unit 103 and the light source. The parts 105 are alternately arranged.

  As shown in FIG. 9B, by increasing the number of the light source units 105 disposed so as to be located at the base of the finger, even when the finger is thick, a vein image can be captured with an appropriate amount of light. Imaging can be performed.

  In the modification shown in FIG. 9B, a case has been described in which the number of the light source units 105 to be disposed is increased as the finger is located at the base of the finger in order to obtain a near-infrared light amount suitable for imaging. However, instead of increasing the number of light sources 105, the maximum value of the amount of light that can be output by one light emitting diode may be changed. That is, if a light emitting diode capable of irradiating high-power near-infrared light is disposed in the light source unit 105 located near the base of the finger, even if the finger is thick, it can be used for imaging. It is possible to obtain a suitable amount of near infrared light.

  A third modification of the finger vein authentication device 1 according to the present embodiment illustrated in FIG. 9C is a modification that illustrates a case where the imaging unit 101 is disposed below the finger F. In the modification shown in FIG. 9C, the placement detection unit 103 and the light source unit 105 are arranged in a line along the finger long axis direction, and include a plurality of placement detection units 103 and light source units 105. Two rows are arranged so as to be parallel to each other. In addition, an imaging unit 101 is disposed between the columns including the placement detection unit 103 and the light source unit 105.

  With such an arrangement, not only the placement detection unit 103 and the light source unit 105 but also the imaging unit 101 can be arranged below the finger, and the surface of the finger vein authentication device 10 can be flattened. Is possible.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Finger vein authentication apparatus 11 Board | substrate 101 Imaging part 103 Placement detection part 105 Light source part 107 Resin layer 109,111 Recessed part

Claims (9)

A plurality of placement detectors disposed on a predetermined substrate for detecting whether or not a part of the finger is placed;
A plurality of light source units disposed on the substrate for irradiating a part of the placed finger with near infrared light having a predetermined wavelength;
An imaging unit for imaging a part of the finger irradiated with the near infrared light;
With
When the substrate is viewed from a direction orthogonal to the longitudinal direction of the finger, the light source unit and the placement detection unit are alternately disposed on the substrate along the longitudinal direction of the finger. Vein authentication device. A resin layer covering the plurality of placement detection units and the plurality of light source units;
The surface on the side where the placement detection unit and the light source unit do not exist in the thickness direction of the resin layer are flat,
The vein authentication device according to claim 1, wherein a part of a finger is placed on a flat surface of the resin layer.   The vein authentication apparatus according to claim 2, wherein the plurality of light source units start irradiation of the near-infrared light when all the placement detection units detect placement of a finger.   The vein authentication device according to claim 1, wherein an interval between the light source units adjacent to each other along the longitudinal direction of the finger becomes wider toward a side where the fingertip is placed.   The number of the light source units arranged along the longitudinal direction of the finger is arranged in a direction perpendicular to the longitudinal direction of the finger as the position of the finger in the longitudinal direction is closer to the base of the finger. The vein authentication device according to claim 1, wherein: The plurality of placement detection units are arranged in a line along the longitudinal direction of the finger,
The vein authentication apparatus according to claim 1, wherein the plurality of light source units are arranged on both sides of a row including the plurality of placement detection units so as to be parallel to the row. The placement detection unit and the light source unit are arranged in a line along the longitudinal direction of the finger,
The vein authentication device according to claim 1, wherein there are a plurality of parallel columns each including a plurality of placement detection units and light source units.   The vein authentication apparatus according to claim 7, wherein the imaging unit is disposed between rows of the plurality of placement detection units and light source units adjacent to each other. The vein authentication device according to claim 1, wherein the plurality of placement detection units are electrostatic sensors, photo sensors, pressure sensors, or Hall sensors.