JP2003331271A - Biometric pattern detection method and biometric pattern detection device, biometric authentication method, and biometric authentication device - Google Patents

Abstract

(57) [Summary] [Problem] To enable permanent biometric authentication without danger of forgery and the like. Biometric identification can be performed simultaneously with biometric authentication. SOLUTION: An unevenness distribution pattern of a deep skin tissue shielded by an epidermis tissue is read, and a pattern unique to a living body is extracted. Biometric authentication is performed based on the read pattern. Reading of the uneven ridge distribution pattern of the deep skin tissue is performed electrically using the difference in electrical characteristics between the epidermal tissue and the deep skin tissue. Alternatively, taking advantage of the fact that the dermal tissue has more blood vessels and relatively higher intradermal temperature than the epidermal tissue, it is read from the temperature difference or the infrared intensity distribution. The detection target position is, for example, a branch portion of a subcutaneous blood vessel, and the detection target position is determined from the shape of the branch portion. At this time, it is also possible to use the subcutaneous blood vessel to identify the living body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel biological pattern detection method and biological pattern detection apparatus capable of capturing a deep skin pattern such as dermis, and further,
The present invention relates to a biometric authentication method and a biometric authentication device to which this is applied.

[0002]

2. Description of the Related Art Fingerprints, palm prints, etc., which are widely used for personal authentication, are the parts where the ridge network formed by the skin's epidermal tissue sinking into the uneven structure of the dermis can be seen directly from the outside. Indicates the deep skin structure such as dermis.
The skin of parts such as palms and soles is different from the skin of other parts due to physiological reasons such as the purpose of facilitating the detection of external stimuli by the tactile nerve terminals distributed in the deep skin and the strength against friction. It has a unique skin structure in which the shape of the deep skin structure and the shape of the epidermis match. The fingerprint that has been conventionally used for personal authentication basically utilizes the permanence of this deep structure.

[0003]

By the way, in the biometric authentication using the fingerprint, the countermeasure against so-called "spoofing" is not always sufficient. For example, fingerprints easily remain as marks on other objects and are easy to see, so the risk of being forged by a third party cannot be denied.

On the other hand, if it is possible to perform biometric authentication using the epidermis of another part, it is considered that the risk of forgery can be avoided. However, the epidermal layer is fluid such that all cells are replaced every 28 days, and various changes are caused by rough skin, dryness, etc. Therefore, the pattern of this part is not permanent. In addition, as a result of the measurement, in the finger trunk and the ball of the thumb, the fingerprints on the epidermis and the epidermis are completely different and even tend to be orthogonal, unlike the fingerprints on the fingertips. Can not.

Unlike special cases such as fingertips where the deep structure is directly reflected on the epidermis and can be visually observed, most of the human body including the skin of the palm part such as the ball of the foot, the finger trunk and the back of the hand, even though it is the same palm type In the skin, the deep-layered pattern does not match the epidermal-layer pattern, and the visible light is blocked by melanin pigments such as scatter and basal cells due to the 6-layered epidermal structure. Is also difficult. Therefore, for example, when a ring-type authentication device is formed, the skin pattern that contacts the inside of the ring when worn cannot be used for authentication as it is.

On the other hand, the deep-layer structure of the skin is basically peculiar to the living body, and there is almost no secular change as is said by fingerprints. The permanence of what is called is also due to the nature of similar sites. Therefore, the subdermal pattern, which is a deep structure of the skin, is considered to be suitable for biometrics, but it may not be intuitively visible or may leave no trace even if it comes into contact with an object, and biometrics equivalent to fingerprints. Despite its characteristics, it was never considered as a personal authentication method.

The present invention has been proposed in view of such a conventional situation, and a biological pattern detection method and biological pattern detection capable of grasping the uneven bump distribution (subepithelial pattern) of deep skin tissue hidden under the epidermis. The purpose is to provide a device. Furthermore, the present invention is a "spoofing" by forgery or the like.
An object of the present invention is to provide a biometrics authentication method and a biometrics authentication device that can perform permanent biometrics authentication without the danger of

[0008]

The present inventor has made various studies in order to achieve the above object. As a result, the difference in the electrical characteristics between the epidermal tissue and the deep skin tissue or the difference in temperature is used to identify them, and the uneven ridge distribution pattern of the deep skin tissue that is shielded by the epidermis and difficult to see is clarified. It is possible to detect the pattern even on the skin and subcutaneous tissue of the whole body other than the special place where the dermis layer pattern and the epidermis layer pattern match like a fingerprint.
We have come to the knowledge that this can be applied to biometric authentication (personal authentication).

The present invention has been completed based on such findings. That is, the biological pattern detection method of the present invention electrically reads the shape of the subepidermal tissue shielded by the epidermal tissue by utilizing the difference in the electrical characteristics between the epidermal tissue and the deep skin tissue, and extracts a pattern unique to the biological body. Alternatively, the shape of the subepithelial tissue shielded by the epidermal tissue is read by utilizing the temperature difference between the epidermal tissue and the deep skin tissue, and a pattern peculiar to the living body is extracted. It is a thing.

Further, the biological pattern detection device of the present invention is
It is characterized by having a means for electrically reading the shape of the subepidermal tissue shielded by the epidermal tissue by utilizing the difference in the electrical characteristics between the epidermal tissue and the deep skin tissue, and extracting a peculiar pattern to the living body. Yes, or using a temperature difference between the epidermal tissue and the deep skin tissue to have a means for reading the shape of the subepidermal tissue shielded by the epidermal tissue, and is characterized by extracting a pattern peculiar to the living body. .

Further, according to the biometric authentication method of the present invention, the pre-registered pattern is obtained by electrically reading the shape of the subepithelial tissue shielded by the epidermal tissue by utilizing the difference in the electrical characteristics between the epidermal tissue and the deep skin tissue. It is characterized in that biometric authentication is performed by collating with, and the shape of the subepidermal tissue shielded by the epidermal tissue is read using the temperature difference between the epidermal tissue and the deep skin tissue, and is registered in advance. It is characterized in that biometric authentication is performed by collating with the above pattern.

Furthermore, the biometric device of the present invention has means for electrically reading the shape of the subepidermal tissue shielded by the epidermal tissue by utilizing the difference in the electrical characteristics between the epidermal tissue and the deep skin tissue, It is characterized in that biometric authentication is performed by matching with a pattern registered in advance,
Further, it has a means for reading the shape of the subepithelial tissue shielded by the epidermal tissue by utilizing the temperature difference between the epidermal tissue and the deep skin tissue, and biometric authentication is performed by collating with a pre-registered pattern. It is a feature.

The basic concept of the present invention is not to use the pattern of the epidermis for authentication but to detect and use the pattern of deep skin tissue, for example, the dermis layer, for authentication. The uneven ridge distribution pattern (texture), which is the subepidermal tissue shape of deep skin tissue, is unique to the living body like fingerprints, palm prints, plantar prints, etc., and is not only permanent with little secular change, but also, for example, fingertips. Except for the part that can be recognized as a fingerprint, most skins do not match the pattern of the epidermis layer and are hidden by the epidermis structure, so it is difficult to see from the outside. Moreover, even if it touches an object, no trace is left. Therefore, its forgery is almost impossible.

Furthermore, according to the present invention, as described above, the shape of a dead tissue such as a skin dead layer due to the loss of nuclei such as skin keratin is not captured, but the shape of a living tissue called deep skin tissue is captured. ing. This deep skin tissue cannot maintain its pattern when separated from the living body. For example, there are capillaries in the deep skin tissue, but the blood flow pattern of the capillaries is peculiar to a living body, and when the tissue is separated from the living body, vascular atrophy,
Immediately disappears due to blood flow stoppage, blood loss, etc., and also affects the pattern of the entire deep skin tissue. Therefore, in the present invention, biometric authentication and biometric identification are integrated, "impersonation" by obtaining biological tissue is impossible, and biometric authentication in the true sense is realized.

The above-mentioned subepidermal tissue shape of the deep skin tissue, for example, the uneven ridge distribution pattern of the dermis layer, is composed of epidermal tissue which is an aggregate of single cells and their trace tissues and dermal tissue which is dense connective tissue. The difference can be electrically detected by utilizing the difference in the electrical characteristics.

In the skin structure, the epidermal tissue has no blood vessels and is passive with respect to body temperature, whereas the dermal tissue has a vascular network and actively generates body temperature due to blood flow. To do. Based on such a mechanism, the temperature of the dermis tissue is relatively higher than that of the epidermis tissue. Therefore, the shape of the epidermis tissue can be detected by utilizing the temperature difference. At this time, paying attention to the fact that the body temperature of the living body emits infrared rays having a specific wavelength, it is possible to detect the temperature difference as the infrared intensity difference.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a biometric pattern detection method, a detection apparatus, a biometric authentication method, and an authentication apparatus to which the present invention is applied will be described in detail with reference to the drawings.

[0018] For example, in the case of biometrics authentication using a fingerprint, since a trace (fingerprint) easily remains on other objects and is easy to see, the risk of being forged by a third party cannot be denied. A separate physiological biometric identification is required to determine whether the fingerprint obtained is that of the finger of the living body. This is because in biometrics authentication using fingerprints, the shape of dead tissue such as skin corneum is directly captured optically and electrically.

It can be said that the security strength of the fingerprint, iris, or other biometric authentication means does not depend on the detection accuracy, but rather on the confirmation of the physiological biological belonging. If it is broken, it becomes possible to easily “spoof” by obtaining the biological tissue to be authenticated, and in that sense, the security strength of the system is essentially equal. In the case of general credit card security, even if it is broken through, it will not cause any direct harm to the living body due to only economic loss, but the "impersonation" due to the acquisition of the above-mentioned biological tissue is a serious problem for the living body. This will result in a new disaster. Hereafter, this will be referred to as a Surgical Hazard.

In biometric authentication, in addition to the local security strength used in general authentication technology, a new system requires the concept of security strength against surgical disasters, including user safety. Security must be taken into consideration, but the point is not clarified in the prior art.

That is, the security as biometric authentication identifies "authentication" as "living tissue that does not correspond to the person himself or is not cut from the person" and a normal living body to be authenticated. "Organization identification"
However, in the conventional biometric authentication technology, only the accuracy and reliability of the former authentication are simply focused on. In this case, although it is called biometric authentication, in reality, the object is authenticated without "living body identification", which causes a contradiction that it is not actually "biometric" authentication. Therefore, when viewed as a security system including actual operation, it can be said that such a contradiction may induce a secondary disaster called a surgical disaster.

The "spoofing method", which is the simplest and does not require any technical knowledge or equipment, is a method in which a third party authenticates by cutting / extracting tissues such as fingers, arms, and eyes from the living body.
Even if the economic value is less than that of an individual small deposit, the introduction of such biometric authentication means will cause serious damage to the user's life and body, which is difficult to convert into money, due to the simplicity of the method. Will result. Therefore, the conventional biometric authentication method using a fingerprint, an iris of the eye, or the like is used as a supplementary means to other authentication means, or is used in a vaguely limited form such as a simple application. It is difficult to spread.

On the other hand, in the method of relatively easy forgery such as biometric authentication by the fingerprint, taking fingerprint authentication by capacitance as an example, as a countermeasure against forgery, humidity (moisture content) containing salt such as sweat on the fingerprint surface is used. ) Makes the skin surface function as a conductor, and measures the capacitance or electrostatic induction between the electrodes to detect the distance between the microelectrodes and the skin surface to capture a fingerprint pattern. ing. In this sense, this is an example of attempting to identify a living body. This is because the above measurement cannot be performed without the presence of electrolytic humidity containing salt such as sweat secreted from the living body.

However, in the detection method, the presence of electrolytic humidity is required for the authentication target, but it is not necessary that it is of biological origin, and other than this, it is detected that it is not cut out, for example. Living body affiliation identification is not established. Therefore, it is difficult to eliminate the imitation product in which a fingerprint pattern is formed on a gel-like substance having water-retaining property, or a cut finger in which physiological saline is sprayed or dipped.

In addition, in biometric authentication using DNA or the like, it is certainly difficult to "counterfeit" the DNA itself, but whether the DNA to be authenticated belongs to the living body,
It is essentially impossible to determine whether or not a corpse or hair was mass-replicated by PCR or the like, and this is also a method in which living body affiliation identification is not established. For this reason,
In addition to biometrics, infrared blood flow detection of fingers, etc.
In addition to the biometric authentication itself, it is necessary to take measures such as adding a new sensor that identifies the body by some method.

Here, biometrics authentication is separated into two parts, "biometrics / authentication", and is different from biometrics authentication. If the authentication is a front door, the biometrics identification of the authentication target is identified. Relying on physical detection apart from authentication presents the same problem as creating a back door. This inconsistency means that if the biometric identification means of the back door can be deceived, the security as an authentication system at that point breaks down, and "spoofing" using an object or
Furthermore, there is a risk of inducing a surgical disaster. Living body affiliation identification is to identify "whether or not it is a living tissue" on the premise of a biological tissue rich in diversity, but as it is clear even in the Central Dogma that what life is, it alone There is an inherent problem that fraud is possible as a result of the fact that the frontier of discrimination becomes large because of the diversity. It can be said that in the conventional method in which the detection means used for biometric authentication and biometric identification are separately prepared, a third party could easily discover and analyze the biometric identification sensing method. There is a demand for a true biometric authentication method in which authentication and biometric identification are integrated, and authentication is biometric identification and there is no back door.

Therefore, in the present invention, rather than utilizing the epidermal pattern such as the fingerprint, the uneven ridge distribution pattern of deep skin tissue, for example, the dermis layer is detected, and biometric authentication is performed using this. And

FIG. 1 is a schematic diagram of a skin tissue, which is roughly divided into an epidermis 1 and a dermis 2. Epidermis (Epid
ermis) 1 is keratinized stratified squamous epithelium, and stratum corneum 1
1, transparent layer 12, granular layer 13, spinous layer 14, basal layer 1
5 and the basement membrane 16. Among these layers, the granular layer 13, the spinous layer 14, and the basal layer 15 are collectively referred to as Malpighian layer.

The stratum corneum 11 has a lamellar liquid crystal form due to a bilayer membrane of intercorneal lipids, the transparent layer 12 has a cholesteric liquid crystal form, and the granule layer 13 is a bead that reflects and scatters light called keratohyaline granules. The cytoplasm contains a basic structure having such optical properties. In addition, the basal layer 15 has various melanin granules, such as melanin granules, to optically protect the living body from external ultraviolet rays.
It has an absorption form. Particularly for light in the ultraviolet band, the epidermis has a certain dichroic property due to the multilayer thin film structure having different refractive indexes. However, basically, the epidermis 1 is a semitransparent tissue having a relatively scattering property even in the visible light region except for the coloring by the melanin pigment. However, the transmittance is higher in a wavelength band longer than that of red of visible light or near infrared. For this reason, the blood flow in the capillary network of the dermis 2 under the epidermis 1 is scattered and can be observed from the outside as, for example, a complexion or blood color, and the skin color is basically the melanin pigment and the dermis 2. It is determined by the blood in the capillaries. The epidermis 1 has no circulation of electrolytes such as capillaries and lymph, and basically has a strong dielectric property as represented by the stratum corneum 11.

On the other hand, the dermis (Dermis) 2 has a completely different appearance compared to the epidermis 1. Basically, the dermis 2 is composed of dense connective tissue composed of collagen and elastin and a capillary network, and is greatly different from the epidermis 1 which is an aggregate of cells and has no capillaries.

The dermis 2 is divided into a papillary layer and a reticular layer. The papillary dermis is a tissue that is in contact with the epidermal tissue by the basement membrane, which is the lowermost layer of the epidermal tissue, is composed of connective tissue and capillaries, and has sensory nerve endings. The reticular layer is composed of collagen having a certain array structure, elastin that connects them, and a matrix that fills the gap between them. The dermis 2 is rich in capillaries and rich in electrolytes due to circulation of lymph and the like, and therefore has significantly higher conductivity than the epidermis 1.

In the present invention, by utilizing these differences in electrical characteristics, deep skin tissue (for example, dermal tissue)
The uneven ridge distribution pattern etc. are detected and used for biometric authentication.

FIG. 2 shows an example of a detecting device for detecting the electric potential of the skin by using electrostatic induction and thereby detecting the depth of the dermal tissue under the epidermis to obtain the subcutaneous pattern. In this detection device, when viewed relatively, the skin layer has a property as a dielectric and the dermis layer has high conductivity, and therefore electrostatic charges generated between the detection electrode and the dermis layer are utilized. Detect capacity.

In order to detect the electrostatic capacitance, in the detection device shown in FIG. 2, a plurality of micro electrodes 21 are formed in a two-dimensional array or the like by micromachining or the like on the detection surface to be brought into contact with the skin surface. It is used as the detection electrode surface. Capacitive coupling is generated between each microelectrode 21 on the detection electrode surface and the dermis layer, and the distance distribution of the subepithelial conductive layer under each microelectrode 21 is obtained from the electrostatic capacitance according to the distance to the electrode. From this distribution Detect subepidermal tissue shape. That is, capacitors are formed between the microelectrodes 21 arranged in parallel on the skin and the skin, and the terminal voltages of these capacitors are measured to detect the shape of the dermis layer from the values.

The microelectrode 21 is enclosed in a cylindrical housing 22 made of, for example, a metal and supported by an insulating carrier 23, and electrically connected to the housing 22 via a resistor 24 having a high resistance. It is connected to the. A space is provided between the microelectrode 21 and the case 22, and when the case 22 is brought into contact with the skin, the microelectrode 21 is separated from the skin at a predetermined distance in the opening 22a of the case 22. opposite.

However, the problem here is that the surface of the skin has the property of a dielectric, and therefore the external AC
It is easy to be influenced by noise of a power source or a fluorescent lamp, and the surface shape of the corneal layer is peeled off or scraped off. Therefore, in fingerprint detection or the like, a method of applying a high-frequency electric signal to the skin of the human body to detect it has been considered, but such a method is used when the epidermis and the dermis pattern match, such as a fingerprint. Applicable, but will detect epidermal patterns in other parts of the skin tissue where they do not match. In this case, the epidermis pattern has no constancy like a fingerprint and cannot be used for biometric individual authentication.

Therefore, in order to deal with these problems,
For example, as shown in FIG. 3, a dielectric thin film 25 is provided in the opening of the metal housing 22. A dielectric thin film 25 is disposed between the skin surface and the metal surface 22 which is connected to the ground side covering the microelectrodes 21 and is brought into contact with the surface of the skin. Form a capacitor. As a result, the shape is less affected by the instability of the skin keratin.

An electret coating 26 is provided on the surface of each micro electrode 21 provided on the detection electrode surface. The electret coating 26 is a film made of tetrafluoroethylene or the like in which charges are semipermanently held. By the permanent polarization of this electret coating 26,
Capacitance serving as a bias is generated between the dermis tissue (conductive tissue), and the distribution of the capacitance difference between the microelectrodes 21 is detected without applying a high frequency bias from the outside to non-invasively. It is possible to detect a deep skin shape such as a dermis layer from the skin surface.

In the detection device having the structure shown in FIG.
The microelectrode 21 having the electret coating 26 arranged from the opening 22a opened to the skin side forms a capacitor with the skin via the dielectric thin film 25. In the case 22, the electrode facing the skin is the ground side, and the opening 22a side is the detection electrode side. For this reason, the epidermal potential fluctuation components that are commonly input to both have mutually opposite polarities and cancel each other out.

On the other hand, the potential fluctuation in the deep skin causes a capacitance between the conductive dermis layer and the microelectrode 21 as the detection electrode, which can be detected from the microelectrode 21. Since there is no bias such as electret on the 22 side, the potential change in the deep skin layer cannot be detected due to the surface charge. Therefore, it is possible to cancel the influence of induction and charging of the skin surface and accurately detect only the potential change in the deep skin layer.

When the potential change extracted above is measured at each point on the skin, the amplitude detected at each point changes due to the capacitance change due to the thickness of the epidermis. In FIG. 4, by arranging the detection electrodes (microelectrodes 21) in a two-dimensional matrix, the shape of the subcutaneous conductive layer is obtained by the difference in the amplitude of the potential change that occurs in synchronization with the entire human body when walking. It is a thing.

As shown in FIG. 5, when walking, the change in the amount of electric charge in the same phase in synchronization with the entire human body causes the ground contact with the road surface of the foot.
Caused by peeling. Explaining the change in human body charge amount with walking, the waveform detected by the capacitance type sensor formed on the skin surface with walking is generated by the following two mechanisms.

The first mechanism is basically the same as the condenser microphone. In the case of a microphone, the distance between the diaphragm and the electret electrode changes due to the vibration of the diaphragm, which changes the capacitance (C) of the gap. Capture by converting impedance. In the present invention, the diaphragm of the microphone is removed, and the sensor and the human body are brought into close contact with each other through the dielectric film to charge-couple them. A capacitor (electrostatic capacity) is formed in the gap between the electret and the dielectric film, and at the same time, the capacitance of the human body and the capacitance of the gap are combined by charge coupling with the human body. When this state is formed, when the human body interacts with the outside world (grounded object, etc.) due to walking motion, etc., and its capacitance changes, it is directly detected by the sensor as a waveform signal like voice detection of a microphone. It

Here, the human body capacitance (C) changes depending on the ground contact with the road surface and the position of the foot in the space. In other words, when it is in contact with the road surface, the capacitance is large, and when the foot is away from the road surface, an air layer having a low dielectric constant is formed between the sole of the foot (sole) and the road surface, and the capacitance is remarkably reduced. The larger the contact area of the foot with the road surface, the larger the capacity. The capacitance C of the capacitor is C = ε · S / d [F] (ε is the permittivity of the medium that fills the gap between the electrodes, S is the electrode area, and d is the distance between the electrodes). Therefore, if the ground contact area of the foot is large, the electrode area (S) is also large and the capacitance is large.

The second mechanism is that the electrode itself acts as a charge sensor, and the electrode inside the sensor, which is enclosed in a metal cylinder and is in contact with the skin through the dielectric film, is a dielectric body due to the charging of the human body. The potential change of the electrode voltage induced on the film is detected as a waveform.

Therefore, it is considered that the waveform detected from the human body by these two mechanisms is basically not the electric potential but the electric charge amount, and it is a phenomenon according to the following equation, and the observed waveform is also obtained by the simulation of the equivalent circuit. Reproduction was confirmed. Q (charge amount) = C (capacitance) V (electrode voltage)

The change in the amount of charge basically has the same waveform throughout the body, but the amplitude varies depending on the fine structure of the skin tissue, particularly the relationship between the epidermis and the dermis layer. Since the charge variation waveforms are synchronized throughout the body, the distance to the dermis layer at each electrode is measured by comparing the amplitude differences with the fine detection electrodes configured in the above-mentioned two-dimensional matrix, and the shape of the subepidermal shape is measured. Can be obtained.

As described above, the amount of charge is routinely changed in the human body by the objective movement such as landing and leaving of the foot during walking without using active charge generating means such as electrodes for applying electric charge. Utilizing this, each microelectrode 21 detects a change in the amount of electric charge that occurs with activities such as walking and movements, and each microelectrode 21 having a waveform of the amount of electric charge that changes in synchronization with the whole body with exercise It is possible to detect the shape of the deep skin layer such as the dermis layer under the detection electrode surface by converting the amplitude difference in A to the distance between the skin surface and the subcutaneous tissue.

Conventionally, as skin fingerprint detection by electrostatic capacity or resistance, a microelectrode is formed on the detection surface by micromachining as a fingerprint detection technique, and when the finger touches the microelectrode, the fingerprint grooves and ridges are formed. Is known by electrostatic capacitance or electrostatic induction (for example, JP-A-8-30583).
No. 2, JP-A-11-19070, JP-A-200
1-311754). In addition, a method of performing personal authentication using a pattern formed by surface irregularities using a one-dimensional resistance distribution corresponding to the skin irregularities pattern of the finger trunk instead of a fingerprint (Japanese Patent No. 2971296) and the influence of sweat on the skin surface As a method of eliminating the skin noise, there is also a method of obtaining a skin pattern by using the difference in impedance due to the contact / non-contact with the electrodes due to the unevenness of the skin under each electrode It is considered (Japanese Patent Laid-Open No. 2000-242770).

However, these conventional skin print detection methods are intended only for detecting print prints on the surface layer, regardless of whether they are capacitance, pressure or resistance methods.
It can be applied only to a part of palm-shaped skin in which the ridges of the subcutaneous dermis layer and the epidermis are the same. If authentication is attempted on skin other than a part of the palm-type skin, non-permanent prints on the epidermis will be detected, which is not suitable for practical use on the skin in general. In addition, in the conventional method that simply uses the electrical and optical characteristics of the skin surface, it is difficult to identify the living body affiliation, and it is necessary to separately provide some living body affiliation identification means as a countermeasure against the back door, and the configuration is complicated. There is concern about security as it becomes more common.

Further, it is considered that the conventional electrostatic capacitance method is basically based on the assumption that a fixed type authentication device is used, and the device is grounded. Therefore, for example, in a wearable environment in which the authentication device is attached to the human body and the wearer authenticates itself, for example, when walking on a carpet during the dry season in winter, both the detection electrode and the grounding part are strongly charged and accurate. It can be difficult to detect. This is because in a wearable environment, the grounding part is also on the human body.

As a solution to such a problem, in addition to the detection electrode, a new transmitting means such as an electrode and a vibrator is prepared so as to be in close contact with the human body, and ultrasonic waves or a constant high frequency signal so as to be actively propagated to the human body. A method has been devised in which a fingerprint pattern is obtained by applying a voltage and receiving it by a microelectrode on the skin to identify the contact surface with the skin and the non-contact surface. However, in such a method, the configuration becomes complicated, and like the fingerprint authentication so far described, the fingerprint is limited to a part of the palm-shaped skin. For example, when it is considered that the skin surface under the ring is used for authentication when it is built in a ring, etc., the pattern of the epidermis layer such as wrinkles tends to be different at that part, although it is orthogonal to the pattern of the dermis layer. In addition, a non-permanent epidermis pattern is detected, which poses a problem in terms of authentication accuracy.

As described above, the present invention detects not the pattern of the epidermis but the shape of the subepidermal tissue (for example, the uneven ridge distribution pattern of the dermis layer) by electrostatic capacitance, and based on this, biometric authentication is performed. The above-mentioned inconvenience is completely eliminated.

That is, in the present invention, since biometric authentication is performed by the shape of the subepithelial tissue, the biometric authentication and the biometric identification match. Therefore, the cut tissue is immersed in physiological saline or the like to remove cells. Even if the above is utilized, since there is no blood flow, this can be authenticated and excluded.
The tissue to be certified must have pulmonary circulation and pulsation, and must properly have the hemoglobin ratio of blood flow and blood, and even if the arm is surgically cut and used, each blood vessel of the arm is surgically cut. It is necessary to connect to an artificial heart-lung machine and accurately reproduce the pulsation waveform. For example, it is difficult to realize it in the present situation where a portable heart-lung machine has not been put to practical use. Even if it is put to practical use in the future, it starts from amputation of the arm, connects to each blood vessel and device, treats the cut microvessels and nerves, eliminates tissue changes due to life reaction to the amputation, and restarts blood flow. It requires advanced surgical techniques and medical equipment, such as stabilization of the tissue later, and is not a realistic task. On the other hand, regarding the three-dimensional three-dimensional structure of fine capillaries, scattering, and the like, it is more difficult to accurately construct the same one artificially without using a living body.

The present invention can also be applied to a wearable environment. For example, in a human-wearable or portable information device, a detection means for detecting a subdermal tissue or a blood vessel pattern which is difficult to see by natural light on a surface where the user's skin comes into contact with the device when the device is held or worn. When the user grips or wears the device, the skin tissue pattern under the epidermis at the contact part between the body and the device is detected and registered in advance in the device or a server connected to the network. It is possible to realize so-called access control in which at least a part of the service provided from the device or the network is permitted or restricted based on the result of comparison with a given pattern.

By the way, the above detection device and authentication device are
For example, in the case of a wrist-worn type body-worn authentication device,
It is necessary to strictly determine the mounting position and the direction at the time of mounting, and it is also necessary to take measures such as keeping the living body in close contact with the living body so as not to move even when the living body is active. Specifically, it is necessary to specify which side of the skin is the subject of authentication. A method of pre-registering an interference pattern of a wide skin area including a target area is conceivable, but it is necessary to collate a specific pattern from a pattern of a wide area, which causes a heavy processing load. In the case of a portable device, a heavy load in terms of power consumption is not preferable.

For example, in a biometric authentication using a skin pattern, in a special case such as a fingerprint, the center of a vortex, a horseshoe or the like is easily captured, and the shape of the finger surface is limited and narrow. It is easy to specify the position of. However, in general skin excluding such limited and peculiar parts, the area is wider than the fingertips, and a fine skin pattern that does not have a geometrical shape such as a spiral that is easy to locate like a fingerprint. It is extremely difficult to identify the area to be authenticated from among these.

Therefore, as described above, a method of registering a skin pattern in a wide area in advance and searching for whether the pattern detected at the time of authentication is included in the registration pattern can be considered. It takes a lot of time to register, and
The verification process at the time of authentication also requires a processing load and time on the device. In addition, it is ideal to register the skin pattern on the whole body, but it is not practical for the above reasons.In that case, the definition of "wide area" is ambiguous, and in actual operation, the flexibility of the human body and the occasion There is a possibility that the authentication device may be out of the area at the time of individual authentication due to the difference in the authentication target contact.

Therefore, as a method for solving this, it is preferable to use the skin surface to be detected as a branch portion of the subcutaneous blood vessel. By using the shape of the branch, it is possible to easily determine the main axis direction. For example, if the positional relationship of the branch portion of the subcutaneous blood vessel is previously determined and recorded at the time of registration, the skin surface to be detected can be easily aligned with the position of the blood vessel branch portion at the time of authentication.

Next, the detection and authentication of the biometric pattern using the temperature difference will be described. In the skin structure, epidermal tissue has no blood vessels and is passive with respect to body temperature, whereas dermal tissue has a vascular network and actively produces body temperature due to blood flow. Therefore, the dermal tissue has a relatively higher intradermal temperature than the epidermal tissue, except when external heat is applied such as exposure of the body surface to direct sunlight. Utilizing this, the shape of the subepidermal tissue is detected.

For example, instead of the above-mentioned microelectrodes, microelements for temperature detection such as thermistor bolometer and thermopile are made into a two-dimensional array, and the temperature at each point is measured. At this time, a temperature difference occurs between the microelements depending on the thickness of the skin layer under each microelement. By utilizing this, it is possible to detect the uneven distribution of the dermis layer under the epidermis. In particular, by using a thermopile corresponding to the infrared band radiated by the human body for temperature detection, it is possible to eliminate the influence of an external heat source such as sunlight.

Further, for example, paying attention to the fact that the body temperature of the living body emits infrared rays of a specific wavelength (for example, a wavelength of about 10 μm), infrared detecting means as temperature detecting means are arranged in a matrix and brought close to the skin surface, and the epidermal tissue It is also possible to detect the underlying dermal layer pattern. In each of the infrared detecting means arranged in a matrix, the infrared intensity varies depending on the thickness of the epidermis and the distance from the dermis, which is the infrared source. Based on this infrared intensity distribution, the shape of the subepidermal tissue, for example, the uneven pattern of the dermis layer is detected.

In the above, it is also possible to identify the position of the blood vessel by utilizing the fact that the temperature locally becomes higher than that of other portions due to the presence of the subcutaneous blood vessel, and perform biometric authentication using it. Alternatively, it is possible to specify the position and direction of the authentication target based on the detected capillary blood vessel image, and further it is possible to perform living body affiliation identification.

[0064]

As is apparent from the above description, according to the present invention, it is possible to perform ubiquitous biometric authentication with the skin of the whole body rather than a specific place such as a fingertip. Also, unlike the fingerprint, the authentication target is not visible from the outside, and the location on the body is not easily specified like a fingerprint or an iris.
It is highly confidential and difficult to forge.

Furthermore, the present invention is an authentication method using a place such as dermis tissue, which is rich in blood flow and body fluid circulation, and its characteristics are sensitive to these changes. This means that the means and the biometric identification are completely integrated. As a result, the surgical disaster can be nullified and the safety of the user can be improved.

Furthermore, in the detection device and the authentication device of the present invention, since the detection unit can be provided on the human body contact surface of the wearable device, for example, biometric authentication can be completed in daily operation without being aware of the authentication. it can. Further, even if a detection or matching error occurs, the retry is performed without the user being aware of it, so that the user does not have to worry about the authentication retry.

[Brief description of drawings]

FIG. 1 is a schematic diagram of skin tissue.

FIG. 2 is a schematic diagram showing an example of a skin surface potential detecting element.

FIG. 3 is a schematic view showing another example of the skin surface potential detecting element.

FIG. 4 is a schematic diagram showing an example of a subcutaneous tissue pattern detection device in which skin surface potential detection elements are arranged in a two-dimensional array.

FIG. 5 is a waveform diagram showing an example of a potential waveform generated during walking.

[Explanation of symbols]

1 epidermis, 2 dermis, 21 microelectrodes, 22 metal casing, 23 insulating carrier, 25 dielectric thin film, 26 electret coating

Claims (33)

[Claims] 1. A living body characterized by electrically reading the shape of the subepithelial tissue shielded by the epidermal tissue by utilizing the difference in electrical characteristics between the epidermal tissue and the deep skin tissue to extract a pattern peculiar to the living body. Pattern detection method. 2. The biological pattern detection method according to claim 1, wherein the deep skin tissue is dermal tissue. 3. The potential of the skin is measured using electrostatic induction,
The biological pattern detecting method according to claim 2, wherein the depth of the dermal tissue under the epidermis is detected to read the shape of the epidermal tissue. 4. The biological pattern detection method according to claim 3, wherein a plurality of microelectrodes are arranged in parallel on the skin to be detected at a predetermined interval. 5. A method of generating capacitive coupling between each microelectrode and dermal tissue, calculating the distance distribution of the conductive layer under the epidermis from the capacitance of each microelectrode, and detecting the shape of the subdermal tissue. The biometric pattern detection method according to claim 4, which is characterized in that. 6. The microelectrodes are arranged in a metal casing at a predetermined interval via an insulating carrier, and a dielectric thin film is interposed between the metal casing and the skin. 5
The biological pattern detection method described. 7. The biopattern according to claim 5, wherein an electret coating is provided on the surface of the microelectrode, and a permanent polarization of the electret coating generates a capacitance serving as a bias between the electret coating and the dermal tissue. Detection method. 8. The change in the amount of electric charge of a living body caused by exercise is detected by the microelectrodes, and the amplitude difference between the microelectrodes of the charge amount change waveform is converted as the distance between the skin surface and the subepidermal tissue. The biological pattern detection method according to claim 4. 9. A method for electrically reading the shape of the subepithelial tissue shielded by the epidermal tissue by utilizing the difference in the electrical characteristics of the epidermal tissue and the deep skin tissue, and extracting a pattern peculiar to a living body. A characteristic biometric pattern detection device. 10. The biological pattern according to claim 9, wherein the electric potential of the skin is measured by using electrostatic induction, the depth of the dermal tissue under the epidermis is detected, and the shape of the epidermal tissue is read. Detection device. 11. The epidermis is provided with a plurality of micro electrodes arranged in parallel at a predetermined interval on the skin to be detected, and the distance distribution of the conductive layer under the epidermis is calculated from the capacitance of each micro electrode. The biological pattern detecting device according to claim 10, wherein a tissue shape is detected. 12. The microelectrodes are arranged at predetermined intervals in a metal housing with an insulating carrier interposed therebetween, and a dielectric thin film is interposed between the metal housing and the skin. The biological pattern detecting device according to claim 11. 13. The biological pattern detecting apparatus according to claim 11, wherein an electret coating is provided on the surface of the microelectrode. 14. The biometric authentication is performed by electrically reading the shape of the subepithelial tissue shielded by the epidermal tissue by utilizing the difference in the electrical characteristics between the epidermal tissue and the deep skin tissue, and collating it with a pre-registered pattern. A biometric authentication method characterized by performing. 15. The biometric authentication method according to claim 14, wherein the deep skin tissue is dermal tissue. 16. The biometric authentication method according to claim 14, wherein the electric potential of the skin is measured using electrostatic induction, the depth of the dermal tissue under the epidermis is detected, and the shape of the epidermal tissue is read. . 17. A means for electrically reading the shape of the subepithelial tissue shielded by the epidermal tissue by utilizing the difference in the electrical characteristics between the epidermal tissue and the deep skin tissue, and collating with a pre-registered pattern. A biometrics authentication device, characterized in that biometrics authentication is performed by. 18. The biometric authentication according to claim 17, wherein the electric potential of the skin is measured using electrostatic induction, the depth of the dermal tissue under the epidermis is detected, and the shape of the epidermal tissue is read. apparatus. 19. The epidermis is provided with a plurality of micro electrodes arranged in parallel at a predetermined interval on the skin to be detected, and the distance distribution of the conductive layer under the epidermis is calculated from the capacitance of each micro electrode. The biometric authentication device according to claim 18, wherein the tissue shape is detected. 20. A method for detecting a biometric pattern, which comprises utilizing a temperature difference between the epidermal tissue and a deep skin tissue to read the shape of the subdermal tissue shielded by the epidermal tissue, and extracting a pattern peculiar to the living body. 21. The biological pattern detection method according to claim 20, wherein the deep skin tissue is dermal tissue. 22. The method for detecting a biological pattern according to claim 20, wherein minute temperature detecting elements are arranged and the shape of the epidermal tissue is read from the temperature difference between the temperature detecting elements. 23. The biometric pattern detection method according to claim 20, wherein the temperature difference is detected as an infrared intensity difference. 24. A biometric pattern comprising means for reading the shape of the subepithelial tissue shielded by the epidermal tissue by utilizing the temperature difference between the epidermal tissue and the deep skin tissue, and extracting a peculiar pattern to the living body. Detection device. 25. A plurality of temperature detecting elements arranged on the skin to be detected are provided, and the uneven distribution of the subepithelium is detected from the temperature difference between the temperature detecting elements, and the shape of the subepidermal tissue is detected. 25. The biological pattern detection device according to claim 24. 26. A plurality of infrared detection elements arranged on the skin to be detected are provided, and the uneven distribution of the subepidermal surface is detected from the infrared intensity difference between the infrared detection elements to detect the subepidermal tissue shape. 25. The biological pattern detection device according to claim 24, wherein: 27. The biometric authentication is performed by reading the shape of the subepithelial tissue shielded by the epidermis tissue by utilizing the temperature difference between the epidermis tissue and the deep skin tissue, and by matching the pattern with a pre-registered pattern. Biometric authentication method. 28. The biometric authentication method according to claim 27, wherein the deep skin tissue is a dermal tissue. 29. The biometric authentication method according to claim 27, wherein minute temperature detecting elements are arranged, and the shape of the epidermal tissue is read from the temperature difference between the temperature detecting elements. 30. The biometric authentication method according to claim 27, wherein the temperature difference is detected as an infrared intensity difference. 31. A means for reading the shape of the subdermal tissue shielded by the epidermal tissue by utilizing the temperature difference between the epidermal tissue and the deep skin tissue, and performing biometric authentication by collating with a pattern registered in advance. A biometric authentication device characterized by being operated. 32. A plurality of temperature detecting elements arranged on the skin to be detected are provided, and the uneven distribution of the subepithelium is detected from the temperature difference between the temperature detecting elements to detect the subepidermal tissue shape. 32. The biometrics authentication system according to claim 31. 33. A plurality of infrared detecting elements arranged on the skin to be detected are provided, and the uneven distribution of the subepithelium is detected from the difference in infrared intensity between the infrared detecting elements to detect the subepidermal tissue shape. 32. The biometrics authentication system according to claim 31, characterized in that