WO2014115682A1

WO2014115682A1 - Personal authentication device

Info

Publication number: WO2014115682A1
Application number: PCT/JP2014/050969
Authority: WO
Inventors: 堀米　秀嘉; 梅崎　太造
Original assignee: 合同会社３Ｄｒａｇｏｎｓ
Priority date: 2013-01-23
Filing date: 2014-01-20
Publication date: 2014-07-31
Also published as: JP6339025B2; JPWO2014115682A1

Abstract

[Problem] To provide a personal authentication device having a thin and simple structure using a holographic optical element. [Solution] A personal authentication device verifies identity on the basis of biometric information of an object to be authenticated, and is provided with: a light source; a stage on the front side of which the object to be authenticated is disposed; an image capturing means which captures an image of the biometric information of the object to be authenticated; a holographic optical element for lighting which is disposed on a part of the stage and irradiates the object to be authenticated with light from the light source; and a holographic optical element for image capturing which is disposed on another part of the stage and collects light from the object to authenticated into the image capturing means.

Description

Personal authentication device

The present invention relates to a personal authentication technique for verifying identity based on biometric information, and more particularly to a personal authentication device using a holographic optical element.

The technology for authenticating individuals based on the shape, pattern, various features (hereinafter referred to as “biological information”) of fingerprints, veins, irises, retinas, faces, hands, etc. has attracted attention. In particular, the vein pattern is useful as biometric information used for personal authentication because it is not easily affected by the skin surface condition and is difficult to imitate. A personal authentication device using a vein pattern has been proposed (see, for example, Patent Document 1). In Patent Literature 1, a light source that emits light from two directions to the left and right, an imaging unit that images light transmitted through the finger, and light from two left and right directions are irradiated. Accordingly, a personal authentication device including a control device that performs control so as to capture images a plurality of times is described. According to the apparatus described in Patent Document 1, it is said that when a finger blood vessel pattern is imaged with transmitted light, a compact authentication apparatus that does not have a feeling of pressure for the user and is strong against external light can be provided.

Japanese Patent No. 3770241

The apparatus described in Patent Document 1 irradiates light from the left and right sides of a finger placed on a guide unit, and acquires a finger vein pattern by an imaging unit disposed below the guide unit. It is configured. For this reason, it is more compact than a transmission light type device in which a finger is sandwiched between a light source and an imaging system and a finger vein pattern is imaged by transmitted light.

However, in the apparatus described in Patent Document 1, the light source unit that irradiates the illumination light and the light shielding plate for controlling the optical path of the illumination light so as to protrude above the surface of the imaging opening where the finger is placed. Since it is configured, it is difficult to realize a thin, compact and flat structure. In designing optical devices, generally, a certain amount of optical path (distance) is required between the subject and the photographing means (CCD or CMOS), so the volume increases accordingly, and the size of the device is reduced. There was a problem of getting bigger.

And, recent multifunctional mobile phones (smartphones, iPhone (registered trademark)) and the like have a generally flat design with a wide screen of a touch panel type. For this reason, an authentication device having a protrusion as described in Patent Document 1 is not suitable for mounting on these multifunctional mobile phones. Furthermore, the structure having irregularities tends to accumulate dirt, which is not preferable from the viewpoint of cleaning care. A user who seeks authentication must feel his / her finger in contact with the guide portion of the apparatus, and may feel psychological resistance, which is not preferable from the viewpoint of hygiene.

In addition, according to the apparatus described in Patent Document 1, it is possible to acquire a plurality of images by irradiating light with shifting timing from the left and right sides of the finger. The acquired images differ in the areas that are clearly captured depending on how the light hits, but each captured a specific range of the finger from one direction around the optical axis of the imaging system It is not a so-called stereo image having parallax. Also, at the time of authentication, if the way of placing the finger is different from that at the first registration (for example, due to finger rolling (rotation around the longitudinal axis of the finger)), there is a possibility that authentication is not performed correctly.

In addition, in the apparatus described in Patent Document 1, since the arrangement of the light source, the imaging unit, the guide unit, and the like is limited, it is difficult to realize further downsizing and thinning. And since the illumination range and the imaging range are limited, it is difficult to apply the apparatus as it is to an authentication target (for example, palm) larger than a finger.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a personal authentication device that can solve at least a part of the problems.

In order to solve the above-described problem, a personal authentication device of the present invention is a personal authentication device that performs identity verification based on biometric information in an authentication target, a light source, and a stage in which the authentication target is arranged on the front side, An imaging means for imaging the biological information of the authentication target, an illumination holographic optical element that is arranged on a part of the stage and irradiates the authentication target with light from the light source, and another part of the stage And an imaging holographic optical element arranged to collect light from the authentication target on the imaging means.

In the personal authentication apparatus, the imaging holographic optical element condenses light incident from a first direction out of light from the authentication target onto a part of an imaging surface of the imaging unit, and It is preferable that the light incident from the second direction different from the direction of is condensed on another part of the imaging surface of the imaging means. Two images of the biological information are created based on the light incident from the first direction and the light incident from the second direction, and the three-dimensional image of the biological information is created using the two images. Is preferably formed. The imaging holographic optical element preferably has a function of blocking light other than a specific wavelength.

Another personal authentication device of the present invention is a personal authentication device that performs identity verification based on biometric information in an authentication target, and includes a light source, a stage on which the authentication target is disposed, a light guide, and one of the stages. A holographic optical element for illumination that is disposed in a portion and irradiates the authentication target with light from the light source, a holographic optical element for light guide disposed in another part of the stage, and the light guide holo An imaging means for imaging the biometric information of the authentication target, the holographic optical element for light guide guiding the light from the authentication target Reflecting at a larger angle than a predetermined threshold angle of the body, and reflecting the light reflected at an angle larger than the predetermined threshold angle inside the light guide to propagate in the direction of the imaging means And features.

In the personal authentication device, the stage may be used as the light guide. An imaging holographic optical element is provided in the vicinity of the imaging means of the light guide, and the imaging holographic optical element collects light reflected and propagated inside the light guide to the imaging means. May shine.

Any one of the personal authentication devices described above further comprises contact detection means for detecting contact of the authentication target, and the imaging means captures the biometric information of the authentication target when the contact detection means detects contact of the authentication target. It is preferable to do. The light source can supply light of first and second different wavelengths, the imaging means has a variable focus mechanism, and the personal authentication device is connected to an authentication target placed on the stage. Irradiating light of the first wavelength through the holographic optical element for illumination, and forming biological information light generated from an authentication object on the imaging means using the variable focus mechanism, and the stage The object to be authenticated placed on the authentication object is irradiated with light having a second wavelength without passing through the holographic optical element for illumination, and the biological information light generated from the object to be authenticated is captured using the variable focus mechanism. Preferably, the means is imaged.

Furthermore, the light of the first wavelength is infrared light, the biological information light related to the vein is acquired from the authentication target, the light of the second wavelength is visible light, and the biological information related to the vein from the authentication target It is preferable to acquire biological information light different from light. It is preferable that a position where the authentication target is to be placed can be displayed on at least a part of the stage.

In addition, at least one of the illumination holographic optical element, the imaging holographic optical element, and the light guiding holographic optical element is preferably formed in a hologram sheet disposed on the back side of the stage. . The light source may irradiate the illumination holographic optical element from an end of the stage. The illumination holographic optical element preferably irradiates the authentication target with light from the light source at an angle of 45 ° or more with respect to the normal line of the stage. The biometric information in the authentication target may be a finger vein, a finger fingerprint, a palm vein, a back vein, a retina of the eye, or an iris of the eye.

The illumination holographic optical element, the imaging holographic optical element or the light guiding holographic optical element is produced by irradiating a reference light and an object light having a wavelength different from the light of the light source, When light having the same wavelength as the light source is irradiated, it is preferable to generate light having a predetermined angle. Further, the illumination holographic optical element, the imaging holographic optical element or the light guiding holographic optical element is produced by irradiating a green photosensitive material with reference light and object light from a green laser. It is preferable to generate light at a predetermined angle when external light is irradiated.

A portable information terminal device including any of the above personal authentication devices may be configured.

And the portable information terminal device of the present invention is a portable information terminal device having a personal authentication function based on biometric information to be authenticated, which constitutes a screen, the transparent substrate on which the authentication target is arranged, A light source arranged on the back side of the transparent substrate, an imaging means for imaging the biometric information to be authenticated arranged on the back side of the transparent substrate, a holographic optical element for illumination arranged on the back side of the transparent substrate, A light-guiding holographic optical element disposed on the back side of the transparent substrate, and an imaging holographic optical element disposed on the back side of the transparent substrate, wherein the illumination holographic optical element is from the light source Is irradiated to the authentication target, and the light guide holographic optical element emits biological information light from the authentication target at an angle larger than a predetermined threshold angle of the transparent substrate. And the light reflected at an angle larger than the predetermined threshold angle is reflected inside the transparent substrate and propagates in the direction of the imaging holographic optical element, and the imaging holographic optical element is connected to the transparent substrate. The light propagating through the inside is condensed on the imaging means.

According to the present invention, by using a holographic optical element, the optical path length in the thickness direction of the apparatus can be shortened, and is thinner (for example, a thickness of 10 mm or less) than when a lens is used. Thus, a personal authentication device with a simple configuration can be realized, and the cost can be reduced. Further, it is possible to provide a personal authentication device that is flat and has no protrusion. Furthermore, the personal authentication device of the present invention eliminates the need to place a light source or an imaging means facing the authentication target by propagating light from the light source and light from the authentication target through the light guide. There are also advantages such as a reduction in thickness and a high degree of freedom in design. In particular, a flat stage on which an authentication target is arranged can be used as a light guide, and can be easily applied to an existing multi-function mobile phone. In addition, when used for vein authentication or the like, the illumination light can be irradiated to the authentication target at a large angle with respect to the normal line by the holographic optical element, so that the reflected light from the surface of the authentication target that becomes noise can be reduced it can. Further, since the personal authentication device of the present invention uses a holographic optical element, it can have wavelength selectivity, use only light of a predetermined wavelength for personal authentication, and use light of other wavelengths for other Can be used for applications. In addition, a stereo image having parallax can be obtained by using light from two different directions among the light from the authentication target by the holographic optical element. Other effects will be described in the mode for carrying out the invention.

Schematic configuration diagram of a personal authentication device according to an embodiment of the present invention Example of a cross-sectional view of the personal authentication device viewed from the X-axis direction Example of sectional view of personal authentication device viewed from the Y-axis direction (A) and (B) are examples of the arrangement of the light source and imaging means of the personal authentication device. (A) to (E) are examples of optical paths by holographic optical elements. (A) (B) is another example of the arrangement of the light source and the imaging means of the personal authentication device. Other embodiments of personal authentication device of the present invention Still another embodiment of the personal authentication device of the present invention Example of applying the personal authentication device of the present invention to a multi-function mobile phone Explanatory drawing showing an apparatus and method for producing a holographic optical element

[Outline of the present invention]
The present invention is a personal authentication device that performs identity verification based on biometric information in an authentication target, and uses a holographic optical element (hereinafter sometimes simply referred to as “HOE”). The thinning is realized without providing a projection such as a light source on the surface of the stage where the authentication target is arranged. In this specification, the finger vein is described below as an example, but it can be used not only for finger veins, but also for example, palm veins and back veins. Fingerprints, iris, retina, face, hands, ears The present invention can also be applied to various biological information such as shapes, patterns, and various features.

A holographic optical element is an optical member on which a hologram having a predetermined optical characteristic is recorded. A photosensitive material is applied on a hard, soft, or flexible substrate, and a hologram having a predetermined optical characteristic is recorded on the photosensitive material. ing. A hologram is a recording of an interference pattern of two lights (generally called object light and reference light). By irradiating one light onto the hologram, the other light can be reproduced by diffraction. . Also, depending on the direction of the two lights when recording, the reflection type (two lights are incident on the hologram from the opposite surface) can be a transmission type (two lights are incident on the hologram from the same surface side). ). For this reason, when light in a specific angle range is selected as one light and light in a predetermined direction required as the other light is selected, reflection in a predetermined direction is performed when light in a specific angle range is irradiated. Light or transmitted light can be regenerated and angle selectivity can be provided. Further, by making the incident angle of one light different from the incident angle of the other light, it is possible to provide refraction. Further, by making the traveling direction of one light different from the traveling direction of the other light, for example, by making the azimuth angle different, it is possible to provide a deflecting property. Furthermore, the hologram can also multiplex-record holograms having different properties at the same position. For example, at the same position, a plurality of holograms having different angle selectivity angle ranges can be multiplex-recorded. It is also possible to multiplex-record with a reflection hologram. Note that the intensity of diffracted light varies depending on the diffraction efficiency of the hologram.

The personal authentication apparatus of the present invention (refer to FIG. 1 or FIG. 2 hereinafter) includes at least a stage 2 on which an authentication target is arranged, an imaging unit 4 that images biometric information 12 of the authentication target 10, and a light source 5 that supplies light. And an illumination holographic optical element (illumination HOE) 31 for irradiating light from the light source 5 to the authentication target and light from the authentication target (hereinafter referred to as “biological information light”) 53 are collected on the imaging means 4. An imaging holographic optical element (imaging HOE) 32. The personal authentication device of the present invention includes a light guide holographic optical element (light guide HOE) that guides the biological information light 53 to a predetermined position by a light guide (for example, a stage) instead of the imaging HOE 32. In addition to this, an imaging HOE for condensing the light propagated by the light guiding HOE on the imaging means 4 may be provided (see FIG. 7).

The illumination HOE 31 is provided at a position where it can receive light from the light source and can irradiate the illumination target to the authentication target arranged on the front side of the stage 2. The illumination HOE 31 is preferably arranged on the back side or the front side of the stage 2 on the left and right (may be separated) of the opposing positions of the authentication target.

The imaging HOE 32 receives at least a part of the biological information light and is provided at a position where it can be condensed on the imaging means 4. The imaging HOE 32 is preferably arranged at a position facing the authentication target on the back side or the front side of the stage 2.

The illumination HOE 31 and the imaging HOE 32 are preferably environmentally stable when arranged on the back side of the stage 2, but may be arranged on the front side of the stage 2 in order to avoid the influence of light refraction by the stage. The lighting HOE 31 and the imaging HOE 32 are preferably formed as one holographic optical element, but may be provided independently. Further, the illumination HOE 31 may be arranged on one side of the stage 2 and the imaging HOE 32 may be arranged on the other side of the stage 2. If necessary, the illumination HOE 31 and the imaging HOE 32 are arranged on both sides of the stage 2. Also good.

The imaging unit 4 and the light source 5 are preferably arranged on the back side of the stage 2, but the light source 5 may be arranged at the end or inside of the stage 2 as shown in FIG. When the biological information light is propagated by the body, the imaging unit 4 and the light source 5 are not necessarily limited to the back side of the stage 2.

Thus, the personal authentication device of the present invention is preferable because the stage 2 can be configured on a substantially flat surface without providing a protrusion on the stage 2 that increases the thickness of the device. As a result, a flat structure without protrusions on the stage can be realized, and the apparatus can be made compact. However, the present invention is not limited to this, and a gentle depression for placing the authentication target may be provided in a part of the stage 2, or a fine LED may be provided on the stage as an auxiliary light source, Braille or the like indicating a position for placing the image may be provided.

The personal authentication device of the present invention can be applied to various devices that require an authentication function (such as an automatic teller machine, an automatic transaction device, an automatic teller machine, etc.), and as a part of an entrance / exit management system, It can also be arranged perpendicular to the wall. Further, it may be attached to or incorporated in a personal computer, various portable information terminal devices (including multi-function mobile phone devices, PDA (Personal Digital Assistant), tablet terminals, etc.), automobiles, and the like.

In the present invention, the quantity and arrangement of the light source 5, the lighting HOE 31 and the imaging HOE 32 can be arbitrarily set. The illumination HOE 31 can appropriately set the angle and azimuth of the illumination light 52 by utilizing the optical characteristics (angle selectivity, diffraction efficiency, wavelength selectivity, etc.) of the hologram. Similarly, the imaging HOE 32 can appropriately set the angle and orientation for receiving the biological information light 53 from the authentication target and the angle and orientation of the focused light 55 to the imaging means 4.

If the imaging HOE 32 is configured so that light (for example,

reference numerals

53R and 53L in FIG. 2) from at least two directions of the biological information light is condensed in different regions of the imaging means 4, the authentication object is observed. A plurality of images having different directions can be acquired. For example, a so-called stereo image having parallax can also be acquired. Moreover, you may comprise the stereo image of the biometric information in authentication object from these stereo images using an appropriate image processing means as needed. If the registered image is a stereoscopic image and the image captured at the time of authentication is similarly configured as a stereoscopic image, more accurate authentication can be performed.

In the personal authentication device of the present invention, the dimension in the X-axis direction is called the length, the dimension in the Y-axis direction is called the width, and the dimension in the Z-axis direction is called the thickness. A line perpendicular to a plane defined by length (X) × width (Y) is referred to as a normal line N. The + Z direction is referred to as the front side, and the -Z direction is referred to as the back side. The + Y direction is referred to as the right side, the -Y direction direction as the left side, the -X direction as the upper side, and the + X direction as the lower side. In this specification, the angle of light refers to an angle formed by the light traveling direction and the normal N (Z axis) unless otherwise specified. The azimuth refers to an angle formed with the X axis when projected onto the XY plane.

The authentication target only needs to be arranged in a predetermined space (hereinafter also referred to as “authenticable space”) illuminated by the illumination HOE 31 on the front side of the stage 2, and even if the authentication target is in contact with the stage, the stage It may be separated from the contactless state. The ability to authenticate without touching the stage means that the finger or hand does not touch the stage directly, so there is little psychological resistance and hygiene for the user who seeks authentication. As described above, a relatively wide authenticable space can be realized on the front side of the stage by appropriately setting the quantity and arrangement of the light sources and the HOE and the diffraction of the light by the HOE. For this reason, not only a finger but a comparatively large thing, such as a palm, can also be made into an authentication object.

Also, since the shape and size of the HOE can be designed relatively freely, the stage can also be configured to have a curved surface. Depending on how the apparatus is used, the appearance including the stage may be freely designed. Moreover, it is preferable that the personal authentication device of the present invention has a hermetically sealed casing (not shown) integrated with members constituting the stage so as to block outside air, moisture, ultraviolet rays, moisture, chemicals, and the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following is an example of imaging a finger vein pattern by placing a finger along the length of the apparatus at the center of the apparatus stage 2 as an authentication target. However, the present invention is not limited to the following examples.

[Device configuration]
FIG. 1 is a schematic configuration diagram of a personal authentication device according to the present embodiment. 2 and 3 are a cross-sectional view of the personal authentication device shown in FIG. 1 viewed from the X-axis direction and a cross-sectional view viewed from the Y-axis direction, respectively. The personal authentication device includes a stage 2, a hologram sheet 3, and an electronic substrate unit 8 in order from the front side on which an authentication target is arranged. The stage 2 and the hologram sheet 3 may be in close contact with each other or may be provided at an appropriate interval. When the stage 2 and the hologram sheet 3 are configured integrally, they may be collectively referred to as a hologram plate 30. In FIG. 1, for the sake of explanation, the hologram sheet 3 and the electronic substrate 8 are shown separated from each other, but in an actual apparatus, the interval may be set to approximately 10 mm or less. As shown, the thickness is reduced.

Stage 2 is a member that covers at least part of the surface of the housing, and is preferably made of glass or resin. The stage 2 may be provided with

illumination windows

21L and 21R for irradiating illumination light, and an imaging window 22 for allowing light (biological information light) from an authentication target to pass at the time of authentication. It is preferable that a portion other than each window of the stage 2 is provided with a light shielding layer 24 that blocks outside light. However, the above is an example, and the present invention is not limited to this. It is sufficient that at least part or all of the stage 2 has translucency at the wavelengths of illumination light and biological information light (for example, 830 to 890 nm). In FIG. 1, the left and

right illumination windows

21L and 21R and one imaging window are illustrated, but the number and arrangement of each window (translucent region) depends on the form of the apparatus. Can be set as appropriate. Further, instead of each window and the light shielding layer 24, a light shielding mask may be formed on the hologram sheet. The finger 10 is disposed on the front side of the stage 2 so as to face the imaging window 22.

The hologram sheet 3 is a film-like sheet containing a photosensitive material for hologram recording, and a transmissive illumination HOE 31 and an imaging HOE 32 are formed in areas corresponding to the illumination window 21 and the imaging window 22, respectively. Is done. Each HOE is a hologram having predetermined optical characteristics (angle selectivity, diffraction efficiency, wavelength selectivity, etc.), and has a function of emitting light at a set angle and direction. It is preferable to form a light-shielding mask that does not transmit external light except in the region where the illumination HOE 31 and the imaging HOE 32 are formed. In addition, external light may include light close to the near-infrared wavelength used for imaging, and this light may become noise and reduce the authentication rate. For this reason, it is preferable that the imaging HOE 32 has a filtering function that blocks components other than the predetermined wavelength. As a result, the apparatus can be manufactured at a lower cost compared to the case where the narrow band filter is provided in the imaging means. Further, the hologram sheet 3 may be attached to the back surface of the stage 2 or the like. In addition, although the example which forms HOE31 and 32 in a part of hologram sheet 3 was shown in FIG. 2, it is not limited to this. For example, each HOE having a predetermined size may be individually produced and arranged at an appropriate position, or each HOE may be produced by applying a photosensitive material on the back surface of the stage 2 and recording a hologram. .

On the electronic board 8, the imaging means 4 and the light source 5 are arranged at positions corresponding to the illumination HOE 31 and the imaging HOE 32. Although FIGS. 1 to 3 show examples in which the

lighting HOEs

31L and 31R and the

light sources

5L and 5R are arranged on the left and right, and the imaging HOE 32 and the imaging unit 4 are arranged in the center, the present invention is not limited to this. The quantity and arrangement of each component can be appropriately set according to the form of the apparatus.

The imaging means 4 is a sensor that converts incident light into an electrical signal, acquires biological information light, and captures an image of the biological information 12 in the authentication target 10. The imaging means 4 has an imaging surface 40 having a predetermined size. As the imaging means 4, a CMOS (Complementary Metal-Oxide Semiconductor) sensor, a CCD (CCD: Charge Coupled Device) sensor, or the like can be used. The imaging surface 40 receives light (for example, 53R) generated in a first direction and light (for example, 53L) generated in a second direction different from the first direction among the biological information light. , It may be divided into two regions (40L, 40R). However, in order to receive light in the first direction and light in the second direction, two imaging means may be arranged. A collimating HOE 42 for converting incident light into parallel light may be provided on the front side of the imaging surface. As a result, it is not necessary to provide an optical lens for collimation, so that the structure of the apparatus is simplified and the thickness can be reduced.

The light source 5 supplies illumination for capturing an image of biometric information on the authentication target. For example, an LED (Light Emitting Diode), a laser, or the like can be used. When imaging veins as biological information, the light source should be capable of irradiating light having a wavelength in the near-infrared region (700 to 2500 nm, particularly preferably 830 to 890 nm) having a high absorption rate for the hemoglobin component in blood. preferable. When a near-infrared light source is used, the vein portion absorbs light more than the surrounding tissue, so the finger vein is imaged as a dark shadow pattern.

In addition, the personal authentication device includes a power source that supplies power to various components, a control unit (including an image processing unit, an authentication processing unit, and the like) that controls the various components, a storage unit that stores captured images, and a display unit (For example, a liquid crystal display), an input unit (for example, a keyboard), an interface for connecting to an external device (storage system), etc., and an audio input / output unit (speaker, microphone, etc.) may be provided (not shown).

Hereinafter, the operation of the personal authentication device of this embodiment will be described with reference to FIG. 2 (and FIG. 3). Taking the light source (left) 5L disposed on the left side of the electronic substrate 8 as an example, the light beam 51L emitted from the light source (left) 5L enters the illumination HOE (left) 31L. The illumination HOE (left) 31L changes the traveling direction of the incident light beam 51L by the diffraction action of the hologram, and irradiates the authentication target as illumination light with the irradiation angle θ ₁ at the irradiation angle θ ₁ . The light beam 52L may be parallel light, or may be diffused or focused light (hereinafter, the light beam is simply referred to as light for simplicity).

Here, the irradiation angle θ ₁ of the illumination light is an angle formed by the normal line N of the stage 2 and the direction of light, and is set when the HOE is manufactured. In FIG. 2, for the sake of simplicity, the illumination HOE 31 is shown as diffracting and transmitting the light from the light source 5 at the irradiation angle θ ₁ , but the light emitted from the illumination HOE 31 is actually the refractive index of the stage 2. Is further refracted on the surface of the stage 2. The illumination HOE 31 may be set so as to obtain a desired irradiation angle θ ₁ for the authentication target including the refraction angle on the surface of the stage 2. Hereinafter, it is described that the illumination HOE 31 emits light at the irradiation angle θ ₁ unless otherwise specified. However, the irradiation angle θ ₁ includes an angle of refraction at the stage surface or the like.

The present inventors have found that the irradiation angle θ ₁ is preferably 45 ° or more, more preferably 60 ° or more, and most preferably 75 ° by the previous experiment. If the irradiation angle θ ₁ is up to about 75 °, even if the light from the illumination HOE 31 is parallel light, not only the vicinity of the stage of the authentication target 10 but also the side surface can be irradiated to some extent. This is preferable. For simplicity, in FIG. 2, the lighting HOE 31 irradiates light in the YZ plane, but the light from the light source 5 may be deflected in a direction (different orientation) different from the YZ plane.

In our experiment, a near-infrared LED (890 nm) is used as a virtual point light source, the near-infrared LED is placed 70 mm away from the side of the finger to be authenticated, and the CCD camera is placed on the lower surface of the finger. The relationship between the irradiation angle θ ₁ and the authentication rate was examined. Specifically, the irradiation angle θ ₁ was changed every 15 ° from 30 ° to 90 °, and 10 images of four fingers of five subjects were captured, for a total of 200 images. The captured image was compared with the registered image of the subject registered in advance, and the authentication rate was measured. The authentication rate is obtained by subtracting the average error rate obtained from the acceptance rate of others and the rejection rate of identity from 100%.

According to this experiment, 97.13% at an irradiation angle of 30 °, 98.10% at an irradiation angle of 45 °, 98.18% at an irradiation angle of 60 °, 98.82% at an irradiation angle of 75 °, and an irradiation angle of 90 °. An authentication rate of 98.02% was obtained. From these results, it was found that the irradiation angle θ is preferably 45 ° or more, more preferably 60 ° or more, and most preferably 75 °. In the conventional optical member, in the reflection type authentication device, a large irradiation angle (for example, , 60 ° or more) was difficult to achieve. According to the present invention, a relatively large irradiation angle can be set as appropriate by the action of the HOE. As a result, unlike the conventional reflection type device, the personal authentication device is less likely to image the reflected light directly reflected by the surface of the finger skin, so that the vein pattern can be imaged clearly. it can.

Note that most of the external light reaching from the outside of the apparatus is not diffracted by the interference fringes recorded in the illumination HOE 31 and the imaging HOE 32, so that the external light is not deflected by the illumination HOE 31 and the imaging HOE 32. For this reason, for example, the external light traveling in the opposite direction along the same optical path as the irradiation light 52L is transmitted without changing the path and travels to the outside of the apparatus, so that it is less likely to cause noise for the imaging unit 4.

Returning to the description of FIG. 2 again, the illumination light 52L irradiates, for example, the left side surface of the authentication target from the left diagonal back side, and the light reaches various tissues inside the finger and is scattered. The imaging HOE (left) 32L diffracts and transmits light (for example, biological information light 53R) incident from the first direction among the light scattered inside the finger, and the imaging surface (right) of the imaging unit 4 Condensate to 40R. The imaging HOE (right) 32R diffracts and transmits light (for example, biological information light 53L) incident from the second direction among the light scattered inside the finger, and the imaging surface (left) of the imaging unit 4 Concentrate to 40L. The situation where the light beam 51R emitted from the light source (right) 5R reaches the imaging means 4 is the same.

Thereby, the imaging unit 4 can acquire the image of the biometric information to be authenticated viewed from two different directions. For explanation, in FIG. 2, the first direction is a direction from the upper right to the lower left and the second direction is from the upper left to the lower right, but this is merely an example. is there. Two or more different directions may be defined as appropriate, whereby two or more images viewed from different directions can be acquired. In this example, a stereo image having left and right parallaxes is simultaneously imaged on the imaging surface divided into left and right, but the present invention is not limited to this. Control means (not shown) may appropriately control the irradiation timing and imaging timing of the left and right light sources 5 to separately acquire the left and right stereos.

In this example, as shown in FIG. 3, the illumination light 52 irradiated through the illumination HOE 31 and the biological information light 53 received by the imaging HOE 32 are set in parallel to the YZ plane. It is not limited to. The illumination light 52 and the biological information light 53 may be set with a predetermined azimuth around the Z axis according to the usage mode of the apparatus.

[Authentication process]
The authentication process performed by the personal authentication apparatus will be briefly described below. At the time of registration, the user registers, for example, his / her finger vein pattern in advance according to a predetermined procedure. The personal authentication device may store the registered image in a built-in or connected external storage means (including a database). The registered image preferably includes at least two images of the finger vein pattern viewed from different directions. The device used for registration may be a device different from the personal authentication device used for authentication.

At the time of authentication, a user who requests authentication places his / her finger in a predetermined area of the apparatus (for example, the imaging window 22). The finger to be authenticated may be disposed so as to come into contact with the stage, or may be disposed in a state of being lifted from the stage. The personal authentication device activates the light source and applies illumination light to the finger. This illumination light is scattered in various directions inside the finger. The imaging means receives the biological information light that has arrived from a predetermined direction and images a finger vein pattern. The personal authentication device may store the acquired image in the storage means. Next, the authentication processing means compares the registered image with the captured image, calculates the correlation and similarity between the images, and determines the success or failure of the authentication (if it has a certain similarity, it is the person himself / herself) Check). The authentication process is not particularly limited. For example, a method using template matching, Log-Polar conversion (see JP 2007-233981 A), DP matching (see JP 2011-253365 A), etc. By the matching based on the pattern matching, it is possible to use a technique that corrects the positional deviation caused by the positional / rotational deviation of the finger vein and realizes highly accurate authentication.

As described above, according to this example, the stage on which the authentication target is arranged is generally flat, and a thin personal authentication device can be realized. Further, in such a personal authentication device, by appropriately designing the lighting HOE, it is possible to irradiate the illumination light onto the side surface to be authenticated at a relatively large irradiation angle, and to improve the authentication rate. In addition, by appropriately designing the imaging HOE, it is possible to collect biological information light from an authentication target that arrives at least from two different directions on the imaging unit, so that an image having parallax can be acquired. Thereby, an authentication rate can be improved compared with the case where the image seen from one direction is used, and a three-dimensional image can also be comprised as needed.

By the way, the quantity and arrangement of each component such as the light source and the imaging means can be appropriately set according to the form of the apparatus. In addition, the quantity and arrangement of the lighting HOE and the imaging HOE can be appropriately set according to the form of the apparatus.

[Modification]
FIG. 4 is a modified example of the arrangement of the light source and the imaging means of the personal authentication device of this embodiment. FIG. 4A shows an example in which the light sources 5 are arranged in 4 × 2 rows, and the imaging unit 4 is arranged to be shifted in the + X direction from the center of the imaging HOE 32. The imaging HOE 32 collects the biological information light from the authentication target on the imaging unit 4. Thus, by arranging the image pickup means 4 so as to be shifted from the position of the image pickup HOE 32 (offset), an optical distance is secured without increasing the distance in the Z direction between the image pickup HOE 32 and the image pickup means 4. it can. Furthermore, when light is incident on the HOE at a large angle, the diffraction angle varies greatly depending on the wavelength, so that wavelength selectivity can be effectively expressed. Further, since the imaging means 4 is arranged on the back side of the light shielding mask, the noise of external light incident from the front side of the stage 2 is reduced, the signal-to-noise ratio is improved, and a clear image of biological information can be acquired. it can.

FIG. 4B shows an example in which two image pickup means 4 are used and one of them is shifted from the center of the imaging HOE 32 in the + X direction and the other is shifted in the -X direction. In this case, for example, the biological information light incident on the + X half of the imaging HOE 32 is condensed on the imaging means 4 arranged so as to be shifted to the + X side, and is incident on the −X half of the imaging HOE 32. The imaging HOE 32 may be configured so that the information light is condensed on the imaging means 4 that is arranged shifted to the −X side. With this configuration, for example, even if a problem occurs in one imaging unit, an image can be captured by the other imaging unit, so that the personal authentication device can be made redundant.

FIG. 5 shows a specific example of an optical path by each holographic optical element in one aspect of the personal authentication device shown in FIG. 4 (A). FIG. 5A is a front view of the personal authentication device. An imaging HOE 32 is disposed approximately at the center of the hologram plate 30 in the Y-axis direction, and

illumination HOEs

31L and 31R are disposed on the left and right sides thereof. The imaging HOE 32 has different diffraction characteristics between the left region 32L and the right region 32R from the approximate center in the Y-axis direction, and the

illumination HOEs

31L and 31R also have different diffraction properties on the left and right. In FIG. 5, each diffraction laterality is line-symmetric with respect to the Y-axis center.

FIGS. 5B and 5C are a left side view and a top view, respectively, of the personal authentication device, showing the optical path of the light supplied from the light source 5. The lighting HOE (left) 31L diffracts the light from the light source (left) 5L and irradiates the left side surface of the authentication target with the illumination light 52L. The lighting HOE (right) 31R diffracts the light from the light source (right) 5R and irradiates the right side surface of the authentication target with the illumination light 52R.

FIGS. 5D and 5E are a bottom view and a central cross section of the personal authentication device as viewed from the right, respectively, and show an optical path of light condensed on the imaging means. As shown in FIG. 5D, the imaging HOE (left) 31L diffracts the biological information light 53R that arrives obliquely from the right and concentrates it on the imaging surface (left) 40L of the imaging means 4. The light 54R is deflected. The imaging HOE (right) 31R diffracts the biological information light 53L that arrives obliquely from the left, and deflects it into parallel light 54L that is collected on the imaging surface (right) 40R of the imaging means 4.

Note that the above optical path is merely an example, and various changes can be made according to the arrangement and size of various components or the use mode of the apparatus.

FIG. 6 is a modification of the personal authentication device of this embodiment. The example shown in FIG. 6A is a cross-sectional top view of a personal authentication device in which the light source 5 is provided at the end of the stage 2, and the arrangement of the light sources is different from that of the personal authentication device shown in FIG. In this modification, the illumination HOE 31 has a reflection hologram recorded thereon, and is placed in close contact with the back surface of the transparent stage 2 that functions as a light guide. Light from the light source (left) 5L arranged at the edge portion of the light guide is incident on the lighting HOE (left) 31L through the light guide, and has a predetermined irradiation angle θ ₁ as light 52L to be authenticated. Irradiates the left side. The light 52L may be parallel light, or may be light that is diffused or focused. Light from the light source (right) 5R propagates in the same manner.

FIG. 6B is a cross-sectional side view of a personal authentication device in which a plurality of imaging means and imaging HOEs are arranged. In FIG. 6B, a plurality of imaging means and imaging HOEs are arranged in an array in the X-axis direction. A plurality of light sources may be provided as appropriate so as to correspond. If the HOE is manufactured, it can be easily mass-produced by duplicating the master. Therefore, an apparatus in which the imaging HOEs are arranged in an array can be realized at a relatively low cost. Further, according to the personal authentication device of this example, it is possible to secure a wider authenticable space than the example shown in FIG. This example is suitable for, for example, a wall-mounted authentication device used for entrance / exit management and the like. For example, the personal authentication device may include a sensor that detects the height, eyes, shoulder height, and the like of the user. When the sensor detects the height of the user at the time of authentication, the personal authentication device predicts a position where an authentication target (palm or the like) is placed, and activates a light source and an imaging unit corresponding to the predicted position. Moreover, you may show the position where a user should put a hand by lighting a guide light. Alternatively, a guidance HOE may be formed on the hologram sheet, and a three-dimensional guide mark (a frame indicating a hand position, an arrow, etc.) may be projected onto the stage or space by the guidance HOE during authentication. Accordingly, the user can place his / her hand or the like in the authenticable space of the apparatus at an optimal position without taking an unreasonable posture or twisting the wrist according to his / her physique. In addition, since the apparatus of this example has a flat stage and can secure a relatively wide authenticable space, it can be used for animals (for example, dogs, cats, etc.) that are difficult to fully understand human instructions. It can also be applied to individual authentication.

[Other Embodiments]
FIG. 7 is an example of another embodiment of the personal authentication device of the present invention. In this embodiment, the light guide 6 and the holographic optical element 33 for light guide are used, and the biological information light 53 from the authentication target 10 is propagated through the light guide 6 by the light guide holographic optical element 33. Is adopted. In the personal authentication device of FIG. 7, the imaging unit 4 is disposed at a position away from the central axis C of the light guide HOE 33, and FIG. 7 shows an optical path until the biological information light 53 is incident on the imaging unit 4. It is shown.

The light guide 6 is a flat plate made of glass or resin, and reflects light having an angle larger than a predetermined threshold angle _θth on its surface. When light travels from a medium with a large refractive index to a medium with a small refractive index, light with an incident angle larger than the critical angle is totally reflected at the boundary surface. Can be used as However, total reflection does not occur when light travels from a medium with a low refractive index to a medium with a high refractive index. As the boundary surface, the glass surface itself can be used, and the critical angle of the glass determined by the ratio of the refractive index in the glass and the refractive index of the air outside the glass becomes the threshold angle. When the incident angle of the light is larger than the critical angle, the light is totally reflected and does not pass outside the glass and can be used as a light guide. If the stage 2 of the personal authentication device is a medium having a higher refractive index than glass or air, it can be used as a light guide having a critical angle as a threshold angle. Also in FIG. 7, the stage is used as a light guide. However, separately from the stage 2, a light guide 6 made of glass or resin may be provided. Further, the separately provided are the light guide and the stage 2 or stage 2 is used as a light guide, on the surface of HOE33 facing light guide, for reflecting light incident at an angle greater than a predetermined threshold angle theta _th It is preferable to provide a reflective film having angle selectivity. The light guide between the light guiding HOE 33 and the reflective film having angle selectivity does not need to be a medium having a high refractive index, and the light guiding HOE 33 and the reflective film having angle selectivity are separated from each other. And the space between them may be guided (in this case, the light guide is air).

The light guiding HOE 33 is a reflection-type holographic optical element in FIG. 7, and reflects the biological information light 53 from the authentication target 10 at a reflection angle θ ₂ larger than a predetermined threshold angle θ _th to generate the biological information light 54. Is repeatedly reflected inside the light guide 6 and propagates in the direction of the imaging means 4 disposed at a position away from the central axis C of the light guide HOE 33. The biological information light 54 is imaged on the imaging unit 4 by an imaging HOE 32 (formed on the hologram sheet 3 so as to face the imaging unit 4 in FIG. 7) formed in the vicinity of the imaging unit 4. However, in the present embodiment, the biological information light is propagated by the light guide HOE 33 and the light guide 6, so that the arrangement of the imaging means 4 can be designed relatively freely, especially when there is room in space. Instead of the thin imaging HOE 32, the biological information light may be imaged on the imaging means 4 by other means. In this respect, the imaging HOE 32 is not an essential configuration in the present embodiment.

Further, the personal authentication device of FIG. 7 has the contact detection means 9, and the contact detection means 9 may detect that the authentication target has touched a predetermined position. For example, when the contact detection unit 9 detects that the authentication target is in contact with the stage 2 in the authenticable space, the contact detection unit 9 sends a signal to a control device (not shown), emits light from the light source 5, and captures biological information by the imaging unit. You may make it operate. In addition, there is no restriction | limiting in particular as the contact detection means 9, It is possible to use suitably a touchscreen sensor, such as a resistive film system and an electrostatic capacitance system.

In FIG. 7, the stage 2 is used as the light guide 6 and the hologram sheet 3 is disposed on the back side of the stage. However, when the light guide 6 is disposed on the back side of the hologram sheet 3, the light guide HOE 33 is transmitted. A holographic optical element of a type may be used. The personal authentication device of the present embodiment is preferably applied to a portable information terminal, particularly a multi-function mobile phone (smart phone, iPhone (registered trademark)). In FIG. 7, the imaging unit 4 is configured to receive parallel biological information light and acquire an image of one piece of biological information, but is not limited thereto. In the personal authentication device shown in FIG. 7, the light guiding HOE 33 propagates the light generated in the first direction and the light generated in the second direction of the biological information light in the direction of the imaging means 4, and the imaging HOE 32 is The biological information light in the first and second directions is condensed on the imaging means 4, and the imaging means 4 acquires two images of biological information based on the biological information in the first and second directions. It may be configured. That is, the personal authentication device 2 shown in FIG. 7 can also acquire a stereo image having parallax observed from different directions, similarly to the personal authentication device shown in FIG.

FIG. 8 shows an example of still another embodiment of the personal authentication device of the present invention. In the present embodiment, the imaging unit 4 includes a variable focus mechanism, and the position of the front focal plane 45 on the object side can be changed in the Z-axis direction by the variable focus mechanism. A personal authentication device that can acquire the second biological information using the second biological information and the light of the second wavelength will be described. The first biological information and the second biological information are preferably different biological information (for example, vein and fingerprint, glow and retina, etc.), but the same biological information is duplicated with light of different wavelengths. May be obtained to improve accuracy. In FIG. 8,

infrared LEDs

5L and 5R are employed as the first light sources, infrared rays are irradiated from the

infrared LEDs

5L and 5R, information on veins inside the finger is acquired, and the surface light source 50 is used as the second light source. This is an embodiment in which visible light is irradiated from the surface light source 50 and information related to the fingerprint is acquired from the irregularities on the surface of the finger. However, although separate light sources are used in FIG. 8, when light of a plurality of wavelengths is emitted from one light source, both the first biological information and the second biological information are acquired with one light source. Is also possible. When light of a plurality of wavelengths included in one light source is used, the image intensity may be detected by filtering the signal intensity of a predetermined wavelength. For example, if an imaging means provided with RGB color filters is used, biometric information of fingerprints is obtained using information from GB pixels, and biometric information of veins is obtained using R pixels sensitive to infrared. can do.

FIG. 8A is a diagram for explaining a situation in which biological information related to veins is acquired by the

infrared LEDs

5L and 5R, and is basically the same operation as FIG. 2 already described. That is, as described above, the

infrared lights

51L and 51R emitted from the

infrared LEDs

5L and 5R that are the light sources are inclined at a predetermined angle by the

irradiation HOEs

31L and 31R, and the

illumination lights

52L and 52R are emitted to the authentication target 10. Irradiated. The biological information light 53 generated from the authentication target 10 enters the imaging HOE 32 and forms an image on the imaging unit 4 by the imaging HOE 32. Here, in order to observe the vein inside the finger, the imaging unit 4 is adjusted with a built-in variable focus mechanism so that a front focal plane (object plane) 45 is arranged inside the finger.

Next, FIG. 8B is a diagram for explaining a situation in which the biometric information related to the fingerprint is obtained by the surface light source 50. Since the hologram sheet 3 diffracts infrared light and does not diffract visible light so much, the visible light irradiated from the surface light source 50 is not diffracted by the irradiation HOE and imaging HOE of the hologram sheet 3, and is subject to authentication 10 Illuminate as is. The visible light reflected from the surface of the authentication target 10 is not affected by the hologram sheet 3, and an image is obtained by the imaging unit 4. Here, in order for the imaging means 4 to observe the surface of the authentication target 10, a built-in variable focus mechanism is adjusted so that a front focal plane (object plane) 45 is arranged on the surface of the finger. Furthermore, if the position of the front focal plane 45 is changed as appropriate, it is possible to image the belly and the inside of the finger that is the authentication target 10. The fingerprint engraved on the surface of the finger can be acquired.

As described above, in the present embodiment, the imaging means 4 includes the variable focus mechanism, so that different biological information can be detected. In addition, due to the wavelength selectivity of the hologram, light of different wavelengths generates different biological information light through different optical paths. Thus, the personal authentication device of the present embodiment can continuously acquire two types of images of veins and fingerprints by changing the wavelength of light supplied from the light source and the position of the front focal plane 45. It is possible to perform more accurate authentication.

In addition, in the case of having a visible light source as in the present embodiment, when starting the authentication process, a part of the stage 2, that is, the position where the authentication target is to be placed (here, the position of the light guiding HOE 33). It is also preferable to radiate visible light to guide and display the arrangement of the authentication target. Thus, the user can easily know the position where the finger should be placed without providing a physical mark or the like on the stage 2. Note that it is preferable to use a display device as means for displaying visible light because the position to be arranged can be specified more clearly.

FIG. 9 shows an example in which the personal authentication device is applied to the multi-function mobile phone 100. The multi-function mobile phone 100 has a display screen 102, a camera 104, and operation buttons 110, and the display screen is a touch panel system. In the multi-function mobile phone 100 of the present embodiment, a glass substrate covering the surface including the region of the display screen 102 and the camera 104 is used as the stage 2 and the light guide 6. An illumination HOE 31, a light guide HOE 33, and an imaging HOE 32 are disposed on the back surface of the glass substrate (stage), and the imaging HOE 32 preferably has substantially the same refractive index as the light guide 6. Note that a hologram sheet on which an illumination HOE 31, a light guide HOE 33, and an imaging HOE 32 are formed may be attached to the back side of the glass substrate (stage). The arrangement and quantity of each HOE can be appropriately set according to the configuration of the multi-function mobile phone.

As an imaging means for acquiring biological information light, a camera 104 (CMOS or CCD) mounted on a multi-function mobile phone can be used. The camera 104 normally has a variable focus mechanism for changing the focus, and as described with reference to FIG. 8, the front focal plane (object plane) 45 can be changed, and a plurality of pieces of biological information can be acquired. This is preferable.

In addition, it is also preferable to display the position where the authentication target is to be displayed on the display screen 102 of the multi-function mobile phone 100. Unlike the prior art, the personal authentication device according to the present invention no longer requires a protrusion on the surface, so a mark for placing the authentication target is required. This can be solved by displaying this on the display screen 102.

In FIG. 9, the biological information light generated from the authentication target when the light from the light source is irradiated on the authentication target (not shown) by the lighting HOE 31 is guided from the central axis C of FIG. 9 by the light guiding HOE 33. It propagates to the camera 104 provided at the far right upper position. Thereafter, the biological information light propagating through the light guide 6 is imaged on the imaging means 104 by the imaging HOE 32 provided facing the camera 104 as the imaging means. And the control apparatus which is not shown in figure compares the imaged biometric information with what is registered, and authenticates a user.

[Method for producing holographic optical element]
By the way, the HOE used in the personal authentication device of the present embodiment is reproduced using a near-infrared LED light source in order to image a vein. Therefore, it is preferably produced (recorded) using a laser having a near-infrared wavelength similar to that used during reproduction. However, as far as the present applicant knows, at present, there are few near-infrared laser devices suitable for producing HOE, and there is no photosensitive material suitable for such near-infrared lasers.

Therefore, in the present invention, a general and inexpensive photosensitive material (hereinafter referred to as “green-based photosensitive material”), which is a material that can be photosensitive by a green laser, is used for near infrared illumination HOE and imaging. The HOE was prepared (recorded). For example, the green light-sensitive material preferably contains a titanocene compound as a photopolymerization initiator or a combination of a benzophenone compound and a sensitizing dye. The method for producing HOE at a wavelength different from the wavelength at the time of reproduction is described in, for example, “Toshihiro Kubota,“ Introduction to New Version Holography—Principle and Practice ””, Asakura Shoten, November 1995, pp. 26-31. Has been.

FIG. 10 is an explanatory view showing an apparatus and a method for producing a holographic optical element. The recording target portion of the green photosensitive material is arranged in alignment with the reference point O, and the green (wavelength λ _o = 532 nm) of the optical axis is an axis N including the reference point O and perpendicular to the green photosensitive material 3. A laser light source 70 is disposed.

At the time of hologram recording, the green laser light 60 irradiated from the laser light source 70 is separated via the beam splitter 65. One of the separated laser beams 61 (recording reference beam) passes through the aperture 66, is focused by the focusing lens 67, and is applied to the photosensitive material 31. The focus P _r of time can be regarded as a point light source of the recording-specific reference light 61. Here, the distance from the focal point P _r to the reference point O is R _r .

The other separated laser beam 62 (recording object beam) passes through the aperture 68, is reflected by the mirror 69, and is irradiated onto the recording target portion 31 of the photosensitive material. The central axis L of the object light for recording has an angle θ _o with respect to the optical axis N. If regarded recording object beam parallel, the P _o point placed at infinity along the central axis L a good as a point light source of the recording object beam 62. In this example, the distance from the reference point O to the point P _o is R _o = ∞. Due to the interference between the recording reference beam 61 and the recording object beam 62, a hologram is recorded on the recording target portion 31 of the photosensitive material.

At the time of hologram reproduction, a point light source P _c of reproduction reference light in the near infrared (wavelength λ _c = 890 nm) is arranged at a distance of R _c from the reference point O. When the reproduction reference beam 51 emitted from the point light source _Pc passes through the hologram 31, reproduction beam 52 is generated by diffraction. Since the wavelength of the recording reference light and the wavelength of the reproduction reference light are different, the reproduction light 52 differs from the object light 62 in that the central axis L has an angle θ _i with respect to the optical axis N. A reproduction image point P _i (the position of the virtual image of the hologram) is generated at infinity on the central axis of the reproduction light 52. In this example, the distance OP _i may be R _i = ∞. Note that the reproduction reference light 51 and the reproduction light 52 correspond to the light 51 from the light source 5 and the illumination light 52 to the authentication target, respectively, in the personal authentication device of the present invention.

Here, according to the above document “Introduction to New Version Holography—Principle and Practice”, when the wavelength at the time of hologram recording and the wavelength at the time of hologram reproduction are different, the relationship between the reference light, the object light and the reproduction light is generally It is described that it is represented by.

1 / R _i = 1 / R _c + μ (1 / R _o −1 / R _r ) (Formula 1)
sin θ _i = sin θ _c + μ (sin θ _o −sin θ _r ) (Formula 2)
μ = λ _c / λ _o (Formula 3)
In the example shown in FIG. 10, in Equation 1, the object light source point P _o and the reproduction image point P _i are at infinity, so 1 / R _i = 0 and 1 / R _o = 0. In Equation 2, since θ _c = ∠NP _c N = 0 ° and θ _r = ∠NP _r N = 0 °, sin θ _c = 0 and sin θ _r = 0. In Equation 3, since λ _c = 890 nm and λ _o = 532 nm, μ = 1.673. Based on the above equation, the position of the point light source of the desired reproduction reference light and the irradiation angle of the reproduction light can be set.

For example, if the reference point O to set the distance R _c to the light source P _c points of the reproducing reference beam to 10 mm, the distance from Formula 1 and Formula 3, from the reference point O to the light source P _r point of the recording reference beam R _r is as follows.

R _r = (λ _c / λ _o ) · R _c = 16.73 mm
Further, when the reproduction light irradiation angle θ _{i is set} to −75 ° (clockwise is a positive direction), the irradiation angle θ _o of the recording object light is as follows from

Equations

2 and 3. .

sin θ _o = 1 / μ (sin θ _i ) = − 0.577
θ _o = -35.3 °
In other words, at the time of hologram recording, a laser beam of 532 nm is used, an object beam having an angle of −35.3 ° with respect to the optical axis, and a reference from a point light source disposed at a position away from the reference point by 16.73 mm When a green photosensitive material is exposed to light, the hologram recorded thereon is irradiated with reference light having a wavelength λ _c = 890 nm from a point light source disposed at a position 10 mm away from the reference point during reproduction. Reproduction light having an angle of −75 ° with respect to the optical axis is generated.

In other words, when manufacturing the HOE of the personal authentication device, if it is desired to set the thickness of the device (distance from the light source 5 to the HOE 31) to 10 mm, the recording reference light is irradiated by a point light source separated by 16.73 mm from the HOE. That's fine. When the illumination angle of the illumination light 52 is set to 75 °, the mirror may be arranged so that the illumination angle of the recording object light is 35.3 °. As described above, in the present invention, a holographic optical element having desired diffraction efficiency, angle selectivity, and the like can be manufactured using light different from light used for authentication.

[Example]
A hologram sheet 3 that can be used in the personal authentication device of the present invention was produced using the HOE production device shown in FIG. First, a holographic recording medium in which a green photosensitive material was applied on a film substrate was attached to a glass substrate serving as the stage 2 of the personal authentication device. At the time of hologram recording of the lighting HOE 31, a laser beam of 532 nm is used, an object beam having an angle of −35.3 ° with respect to the optical axis, and a point light source disposed at a position away from the reference point by 16.73 mm. The green light-sensitive material was exposed to the reference light. Such a hologram may generate reproduction light having an angle of 75 ° with respect to the normal N when irradiated with 890 nm laser light from a point light source disposed at a position 10 mm away from the reference point during reproduction. The illumination HOE 31 capable of emitting light from the light source at an irradiation angle of 75 ° in an apparatus having a thickness of 10 mm was realized.

Further, when recording the hologram of the imaging HOE 32, the same hologram exposure method as described above is used, the object light and the reference light are set at a desired angle, the green photosensitive material is exposed, and during reproduction, from the vein Receiving 890 nm biological information light incident at a desired angle to generate reproduction light. The reproduction light is 10 mm away from the stage in the Z direction and is located at a position 70 mm away from the central axis of the imaging HOE 32 in the X direction. As a means (not shown), a hologram capable of forming a vein image was produced. As described above, the imaging HOE 32 capable of concentrating the biological information light from the authentication target on the imaging means can be realized.

Furthermore, using the HOE produced by the above method, a personal authentication device was produced, which was formed into a thin rectangular parallelepiped shape and confirmed the identity based on the finger vein pattern placed on the substantially central part of the stage. The personal authentication device according to the present embodiment has a length (dimension in the X-axis direction) of 50 mm, a width (dimension in the Y-axis direction) of 50 mm, and a thickness (dimension in the Z-axis direction) of about 10 mm. (See FIG. 1 or FIG. 2). Stage 2 was made of glass. The side surface and back surface of the apparatus are similarly made of glass, and the entire apparatus has a sealed structure.

Near-infrared LEDs (wavelength 890 nm) were used as the

light sources

5L and 5R, and a CCD camera was used as the imaging means 4. Reference is now made to FIG. The imaging HOE 32 is an array of 8 mm square HOEs arranged in 4 × 2 rows, and the center thereof is attached to the back surface of the stage in accordance with the central axis C of the imaging means 4. The lighting HOEs 31 </ b> L and R are formed by arranging 4 mm × 8 mm square HOEs in 4 × 1 rows and arranged on the back surface of the stage in accordance with the position of the light source 5. The illumination angle θ ₁ of the illumination light is 75 °.

As described above, according to the present invention, it is possible to provide a personal authentication device with a thin structure (for example, a thickness of 10 mm or less) and a simple structure. The stage on which the authentication object is arranged can be configured to be generally flat.

In addition, by appropriately designing the lighting HOE, it is possible to irradiate the illumination light on the side surface to be authenticated at a relatively large irradiation angle, and to clearly capture the pattern of biological information, thereby improving the authentication rate. Can do. Furthermore, by appropriately designing the imaging HOE, the biological information light from the authentication target reaching at least two different directions can be condensed on the imaging means, so that a stereo image having parallax can be acquired. Thereby, an authentication rate can be improved compared with the case where the image seen from one direction is used, and a three-dimensional image can also be comprised as needed.

In addition, since a relatively large authenticable space can be secured on the front side of the stage, the user can place the authentication target at a desired position in a contact or non-contact state at the time of authentication.

2 Stage 3 Hologram sheet 4 Imaging means 5 Light source 6 Light guide 8 Electronic board part 10 Authentication object 12 Biological information 30 Irradiation angle 31 Illumination holographic optical element 32 Imaging holographic optical element 33 Light guiding holographic optical element 40 Imaging surface 51 Light from light source 52 Illumination light 53 Biological information light 55 Focused light

Claims

A personal authentication device for verifying identity based on biometric information in an authentication target,
A light source;
A stage where the authentication target is arranged on the front side;
Imaging means for imaging the biometric information to be authenticated;
A holographic optical element for illumination that is arranged on a part of the stage and irradiates the authentication target with light from the light source;
A personal authentication apparatus, comprising: an imaging holographic optical element that is disposed on another part of the stage and collects light from the authentication target on the imaging means.
The imaging holographic optical element condenses light incident from a first direction out of light from the authentication target on a part of an imaging surface of the imaging means, and is different from the first direction. The personal authentication apparatus according to claim 1, wherein light incident from the direction of 2 is condensed on another part of the imaging surface of the imaging unit.
Two images of the biological information are created based on the light incident from the first direction and the light incident from the second direction, and the three-dimensional image of the biological information is created using the two images. The personal authentication device according to claim 2, wherein:
4. The personal authentication apparatus according to claim 1, wherein the imaging holographic optical element has a function of blocking light other than a specific wavelength.
A personal authentication device for verifying identity based on biometric information in an authentication target,
A light source;
A stage for placing the authentication target;
A light guide;
A holographic optical element for illumination that is arranged on a part of the stage and irradiates the authentication target with light from the light source;
A holographic optical element for light guide disposed in another part of the stage;
An imaging unit that is disposed at a position away from the central axis of the light guiding holographic optical element, and that images the biological information to be authenticated,
The light guide holographic optical element reflects light from the authentication target at an angle larger than a predetermined threshold angle of the light guide, and guides light reflected at an angle larger than the predetermined threshold angle. A personal authentication device, wherein the personal authentication device reflects the light inside the light body and propagates the light toward the imaging means.
The personal authentication apparatus according to claim 5, wherein the stage is used as the light guide.
An imaging holographic optical element is provided in the vicinity of the imaging means of the light guide,
7. The personal authentication apparatus according to claim 5, wherein the imaging holographic optical element condenses the light reflected and propagated inside the light guide onto the imaging means.
Comprising contact detection means for detecting the contact of the authentication object,
8. The personal authentication device according to claim 1, wherein the imaging unit captures the biometric information of the authentication target when the contact detection unit detects the contact of the authentication target. 9.
The light source is capable of supplying light of first and second different wavelengths;
The imaging means has a variable focus mechanism,
The personal authentication device includes:
The authentication object placed on the stage is irradiated with light having a first wavelength via the illumination holographic optical element, and the biological information light generated from the authentication object is used for the authentication using the variable focus mechanism. Form an image on the imaging means,
In addition, the authentication target placed on the stage is irradiated with light having a second wavelength without passing through the illumination holographic optical element, and the biometric information light generated from the authentication target is irradiated with the variable focus mechanism. The personal authentication device according to claim 1, wherein an image is formed on the imaging unit.
The light of the first wavelength is infrared light, the biological information light related to the vein is acquired from the authentication target, the light of the second wavelength is visible light, and the biological information light related to the vein from the authentication target The personal authentication device according to claim 9, wherein different biometric information lights are acquired.
The personal authentication device according to any one of claims 1 to 10, wherein a position where the authentication target is to be placed can be displayed on at least a part of the stage.
At least one of the illumination holographic optical element, the imaging holographic optical element, and the light guiding holographic optical element is formed in a hologram sheet disposed on the back side of the stage. Item 12. The personal authentication device according to any one of Items 1 to 11.
13. The personal authentication apparatus according to claim 1, wherein the light source irradiates light to the illumination holographic optical element from an end portion of the stage.
The holographic optical element for illumination irradiates the authentication target with light from the light source at an angle of 45 ° or more with respect to the normal line of the stage. The personal authentication device according to item.
The biometric information in the authentication target is a finger vein, a finger fingerprint, a palm vein, a back vein, a retina of an eye, or an iris of an eye according to any one of claims 1 to 14. The personal authentication device described.
The illumination holographic optical element, the imaging holographic optical element or the light guiding holographic optical element is produced by irradiating a reference light and an object light having a wavelength different from the light of the light source, The personal authentication apparatus according to claim 1, wherein when the light having the same wavelength as that of the light source is irradiated, light having a predetermined angle is generated.
The illumination holographic optical element, the imaging holographic optical element, or the light guiding holographic optical element is produced by irradiating a green photosensitive material with a reference light and object light from a green laser, and emits near-infrared light. The personal authentication apparatus according to claim 16, wherein when the light is irradiated, light having a predetermined angle is generated.
A portable information terminal device including the personal authentication device according to any one of claims 1 to 17.
A portable information terminal device having a personal authentication function based on biometric information to be authenticated,
A transparent substrate on which the authentication object is arranged on the front side, constituting a screen;
A light source disposed on the back side of the transparent substrate;
An imaging means disposed on the back side of the transparent substrate and imaging the biometric information to be authenticated;
A holographic optical element for illumination disposed on the back side of the transparent substrate;
A holographic optical element for light guide disposed on the back side of the transparent substrate;
An imaging holographic optical element disposed on the back side of the transparent substrate,
The illumination holographic optical element irradiates the authentication target with light from the light source,
The light guide holographic optical element reflects biological information light from the authentication target at an angle larger than a predetermined threshold angle of the transparent substrate, and reflects light reflected at an angle larger than the predetermined threshold angle. Reflected inside the transparent substrate and propagated in the direction of the imaging holographic optical element,
A portable information terminal device, wherein the imaging holographic optical element condenses the light propagating through the transparent substrate onto the imaging means.