JP4827791B2 - Imaging module for biometric authentication and biometric authentication device - Google Patents

Description

  The present invention relates to an imaging module for biometric authentication and the like.

  In recent years, personal devices such as mobile phones, personal computers (PCs), and PDAs (Personal Digital Assistants) have moved to introduce biometric authentication using, for example, finger vein patterns as one of the security measures. In particular, finger vein authentication is not associated with criminal investigations like fingerprint authentication, so it has little psychological resistance, and it is not information on the surface of the living body that can be easily observed from the outside. There is an advantage that forgery is difficult because of the use of features. In order to realize this vein authentication in a personal device such as a notebook PC (notebook type PC), for example, it is desired to develop an imaging module that is smaller and thinner than the conventional one.

As a technique for reducing the size of the finger authentication imaging module, a technique corresponding to Patent Document 1 has been conventionally known.
In Patent Document 1, near infrared light is irradiated from the side of the finger and the direction of the emitted near infrared light is bent by a reflecting mirror, converted into an electrical signal by a CCD sensor, and converted into two-dimensional image data by an authentication unit. Thus, a technique for acquiring biological information is disclosed.

JP 2006-198174 A

Even in the conventional camera module of the small and thin finger authentication imaging module, the optical diaphragm was used to prevent the intrusion of unnecessary light. However, because the camera module has been downsized, the aperture for large unnecessary light has been reduced. The function was not always sufficient.
Here, an object of the present invention is to provide a biometric authentication imaging module or the like that eliminates unnecessary light and obtains stable imaging quality.

  In order to solve the above problems, an imaging module for biometric authentication according to the present invention includes a light source that irradiates a living body with light that passes through the living body, an incident surface that includes an incident area that captures light transmitted through the living body, and an incident area. A prism having a reflecting surface that reflects the captured light; and an exit surface that emits light reflected by the reflecting surface; and an imaging device that converts the light exiting the exit surface of the prism into an electrical signal and outputs the electrical signal. The camera module, the prism, and the camera module are arranged at predetermined positions, respectively, and includes a housing in which a light passage hole through which light emitted from the emission surface of the prism passes is formed.

In the biometric authentication imaging module, the housing is characterized in that the diameter of the light passage hole is determined so that a light amount necessary for imaging by the camera module passes through the light passage hole.
In the biometric authentication imaging module, the casing is made of a material that absorbs light from near ultraviolet to near infrared.
In the imaging module for biometric authentication, the housing has at least a surface facing the prism so that light emitted from the emission surface of the prism is not reflected by the housing and reenters the prism as stray light. Is characterized by being coated to absorb light from the near ultraviolet to the near infrared.

  In order to solve the above-described problems, a housing according to the present invention includes a holding unit that holds a prism that captures and emits light transmitted through a living body in a predetermined position, and converts the light emitted from the prism into an electrical signal. A mounting portion for mounting the camera module to be output at a predetermined position, and the mounting portion is formed with a light passage hole through which light emitted from the prism is allowed to pass and enter the camera module.

  In order to solve the above problems, a prism according to the present invention is reflected by an incident surface including an incident region that captures light transmitted through a living body, a reflective surface that reflects light captured from the incident region, and the reflective surface. It has an exit surface that emits light, and a surface that is formed on a different surface from the entrance surface, the reflective surface, and the exit surface, and is painted to absorb light from near ultraviolet to near infrared. It is characterized by.

  In order to solve the above-described problem, a biometric authentication apparatus according to the present invention captures a light source that irradiates a living body with light that passes through the living body, an incident surface that includes an incident area that captures light transmitted through the living body, and the incident area. A camera module having a prism having a reflecting surface for reflecting light, an emitting surface for emitting light reflected by the reflecting surface, and an imaging device for converting the light emitted from the emitting surface of the prism into an electrical signal and outputting the electric signal And a prism and a camera module at predetermined positions, respectively, a housing formed with a light passage hole through which light emitted from the emission surface of the prism is passed, and an electrical signal output from the image sensor of the camera module Recognizing means for analyzing and recognizing the blood vessel pattern of the living body, holding means for holding the blood vessel pattern of the living body in advance, and the blood vessel pattern recognized by the recognizing means and held by the holding means Characterized in that by comparing the blood vessel pattern including an authentication unit for performing the personal authentication.

  According to the present invention, it is possible to provide an imaging module for biometric authentication that has been reduced in size and thickness.

The best mode (embodiment) for carrying out the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is an external perspective view showing a finger authentication imaging module 1 (hereinafter referred to as an “imaging module”) as an example of a biometric imaging module according to the present embodiment, and FIG. It is sectional drawing of the imaging module 1 concerning.
As shown in FIGS. 1 and 2, the imaging module 1 has a structure in which a prism 12, a lens unit 13, an imaging element 14, and a circuit board 19 are contained in a housing 10. The housing 10 includes an LED 16 as an example of a light source and a light guide 17.

The housing 10 serves as a cover that surrounds and protects the imaging module 1. The casing 10 is formed with a window portion 15 at a position corresponding to an incident region 22a that takes in near-infrared rays by a prism 12 to be described later. The bottom portion of the window portion 15 prevents reflection and transmits infrared light. A black filter 20 that passes and blocks visible light transmission and protects the prism 12 is attached. A light guide 17 having an LED 16 is attached to the housing 10. Further, an irradiation window 18 for irradiating near infrared rays emitted from the LED 16 is formed in the housing 10.
The window portion 15 of the housing 10 corresponding to the incident region 22a of the prism 12 has an end face formed obliquely (see FIG. 3B), and compresses the vein when the finger 50 is placed on the window portion 15. It works so as not to deform. Further, the finger 50 enters the window portion 15 and has a shape that does not hurt even if it touches the edge.

As shown in FIG. 2, the prism 12 is a pentagon having a substantially rhombic cross section. However, this cross-sectional shape is not limited to the shape shown in FIG. Not only the shape shown in FIG. 2 in which the boundary between the first reflecting surface 21 and the incident surface 22 is chamfered, but also a rectangular cross section in which the first reflecting surface 21 and the incident surface 22 are extended. The material of the prism 12 is preferably a resin or glass that is transparent in the wavelength region to be used (visible to near infrared, 500 to 1200 nm). In terms of miniaturization, a higher refractive index is desirable. In the resin, acrylic, cycloolefin polymer, alicyclic acrylic resin, transparent fluororesin, transparent polyimide, epoxy resin, styrenic polymer, polyethylene terephthalate, polypropylene, polyethylene, silicone resin, polyamideimide, polyarylate, polysulfone containing sulfur , Polyethersulfone and the like can be used. A resin in which inorganic particles such as silicon dioxide (SiO ₂ ) and tantalum pentoxide (Ta ₂ O ₅ ) are dispersed may be used. As the glass, general optical glass can be used.
Of the incident surface 22, which is the surface of the prism 12 facing the window 15 of the housing 10, a region where the near infrared rays that directly face the window 15 and are emitted from the finger 50 are incident is referred to as an incident region 22 a.
Surfaces other than the incident surface 22 of the prism 12 will be described later with reference to FIG.

The lens unit 13 is made of resin or glass. The lens unit 13 condenses near-infrared rays that are repeatedly emitted (described later) in the prism 12 and forms an image on an image sensor 14 described later. In the lens unit 13, a band pass filter (not shown) that transmits only a specific narrow band (800 to 1200 nm) of near infrared light is provided.
The image sensor 14 is configured by, for example, a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS), or the like. In order to reduce the size and thickness of the imaging module 1, a VGA module having a size of 1/7 inch type, preferably 1 / 7.4 inch type or less is preferably used. The near infrared light imaged on the light receiving surface (not shown) by the lens unit 13 is converted into an electrical signal and output.

As the LED 16, a light emitting diode (LED) that emits near-infrared light or visible light that is transparent to a living body is used. The LED 16 can be miniaturized, has low power consumption, and has little temperature rise, and thus is suitable as a near infrared or visible light source. The wavelength of the near infrared ray to be emitted is preferably 800 to 1000 nm, more preferably 850 to 950 nm. The wavelength of visible light is preferably 600 nm or more which is permeable to a living body.
The light guide 17 is preferably made of acrylic or other resin that transmits the near infrared rays emitted from the LED 16. As a material of the light guide 17, it is possible to use a combination of the resin and glass mentioned above.

FIG. 3 is a diagram for explaining near-infrared irradiation using the light guide 17.
FIG. 3A is a diagram for explaining a state in which the light guide 17 is attached to the housing 10.
As shown in FIG. 3A, the LED 16 is attached to the side end surface of the light guide 17. And it attaches to the housing | casing 10 so that the radiation | emission surface of the light guide 17 may become the irradiation window 18 side so that near infrared rays can be emitted from the irradiation window 18. FIG. Near-infrared rays emitted from the LED 16 are reflected by the back surface of the light guide 17 and emitted from the emission surface. And it radiates | emits from the irradiation window 18 to the window part 15 side.

FIG. 3B is a cross-sectional view for explaining the arrangement near the window 15 when the finger 50 is irradiated with near infrared rays.
As shown in FIG. 3 (b), the radiation surface of the light guide 17 is directed obliquely upward (the direction behind the finger 50). Therefore, the emitted near infrared rays are irradiated to the back of the finger 50. Thereby, near infrared rays can be irradiated to the vein in the predetermined range of about 3 mm or less from the subcutaneous of the finger.
In the irradiation window 18 of the housing 10, the cover on the prism 12 side (lower side) of the light guide 17 is on a business trip from the radiation surface of the light guide 17. This prevents near infrared rays emitted from the light guide 17 from directly entering the prism 12. Note that the circuit board 19 itself is not directly provided in the imaging module 1 but may be separately mounted in a product to which the imaging module 1 is attached.

  Returning to FIG. 2, the electronic components mounted on the circuit board 19 include a signal processing unit 25 (see FIG. 9) that performs signal processing such as noise removal and correction on the electrical signal output from the image sensor 14, and a signal processing unit. And a recognition unit 26 (see FIG. 9) that analyzes the image signal that has been signal-processed at 25 to recognize and output the vein pattern of the finger 50. The circuit board 19 outputs a vein pattern to the outside based on the electrical signal output from the image sensor 14. This will be described later with reference to the block diagram shown in FIG. The electronic components mounted on the circuit board 19 are arranged in the area of the circuit board 19 excluding the area of the third reflecting surface 23 where the prism 12 abuts on the circuit board 19 in FIG.

The optical arrangement in the imaging module 1 having the above-described configuration will be described below with reference to the drawings.
FIG. 4 is a diagram for explaining the optical arrangement of the imaging module 1 according to the present embodiment.
Near-infrared light irradiated from the LED 16 through the light guide 17 and from the irradiation window 18 is diffused and reflected by the finger 50, and enters the imaging module 1 from the window portion 15.

Near-infrared light incident from the incident region 22 a facing the window 15 in the incident surface 22 of the prism 12 through the filter 20 strikes the first reflecting surface 21 disposed on the opposite side of the incident surface 22. A metal reflective film such as aluminum vapor deposition is deposited on the first reflecting surface 21 to reflect incident near infrared rays.
As shown in FIG. 4, the near infrared light reflected by the first reflecting surface 21 travels in the direction of the incident surface 22 including the incident region 22a. At the incident surface 22, the near infrared light reflected by the first reflecting surface 21 is incident at a predetermined angle with respect to the normal direction of the incident surface 22. Since the incident surface 22 now functions as a reflecting surface, it is also referred to as a second reflecting surface hereinafter.

In the second reflecting surface 22 including the incident region 22a, the incident region 22a is not formed with a reflective film such as metal vapor deposition in order to ensure near-infrared translucency. However, since the area other than the incident area 22a is hidden in the housing 10, the near infrared light does not pass through. Further, the angle of incidence decreases as the distance from the first reflecting surface 21 increases. Therefore, a reflective film is formed in a region other than the incident region 22a. As the reflection film, a metal reflection film such as Al, Ag, Al alloy, Ag alloy, Cu, Au, or a reflection film in which transparent dielectric films having different refractive indexes are laminated is used.
Near-infrared incident light reflected by the first reflecting surface 21 and incident on the second reflecting surface 22 is near in the incident region 22a due to the relationship between the refractive index of the prism 12 and the incident angle on the second reflecting surface 22. Totally reflects infrared rays. On the other hand, even if the incident angle in the region other than the incident region 22a is an angle that does not totally reflect, it is reflected by the reflective film. Then, the near infrared light reflected by the second reflecting surface 22 in this way goes to the third reflecting surface 23 disposed on the opposite side of the second reflecting surface 22.

The third reflecting surface 23 is deposited with a metal reflecting film in the same manner as the first reflecting surface 21, and near infrared rays are reflected and bent in the direction of the exit surface 24. Near-infrared rays travel perpendicular to the exit surface 24, pass through the exit surface 24, and travel toward the lens unit 13. The near infrared light collected by the lens unit 13 is imaged by the image sensor 14. Although no reflection film is provided on the emission surface 24, a reflection film may be provided in a portion other than the transmission region of the emission light in order to prevent incidence of unnecessary light.
A surface different from the incident surface 22 (second reflective surface 22), the first reflective surface 21, the third reflective surface 23, and the output surface 24 (hereinafter referred to as "side surface") is from near ultraviolet to near infrared. Painted to absorb light. By painting the side surface, for example, light in a region from the near ultraviolet to the near infrared is preferably absorbed. More specifically, it is preferable that the wavelength component of light used for biometric authentication (finger authentication) is absorbed. In this Embodiment, since LED16 which discharge | releases near infrared rays or visible light is employ | adopted as a light source, the coating in which the light of the area | region from near infrared to visible is absorbed is preferable.
In the finger 50, near-infrared light is transmitted or diffused in a living tissue having transparency to near-infrared rays such as muscle tissue and bone. On the other hand, for example, a blood vessel portion that absorbs near-infrared rays such as hemoglobin in blood absorbs near-infrared rays. Therefore, in the image formed by the image sensor 14, the blood vessel portion is dark and the other tissue portions are brightly displayed. The image sensor 14 converts the formed image into an electrical signal and outputs it to the circuit board 19.

As described above, according to the imaging module 1 according to the present embodiment, the prism 12 has a plurality of reflection surfaces, and the reflection is repeated a plurality of times in the prism 12. Since the arrangement of the plurality of reflection surfaces is determined by the shape of the prism 12, the arrangement of the reflection surfaces can be accurately performed in a small size, compared to the case where reflection is performed using a plurality of mirrors. Thereby, the imaging module 1 can be reduced in size and thickness. Basically, a reflective film is formed in a region of the reflective surface where total reflection is impossible due to the incident angle.
In the imaging module 1, a long optical path length can be bent and arranged in the thin prism 12. Therefore, the thin imaging module 1 is realizable. In the case of the present embodiment, when the distance from the end of the window portion 15 to the back surface of the image sensor 14 is about 25 mm, the angle between the incident surface 22 and the first reflecting surface 21 is set as shown in FIG. When the complementary angle of the angle between the incident surface 22 and the output surface 24 is 50 degrees, the optical path length can be bent with the prism 12 having a thickness of 5 mm.
According to the imaging module 1, when the size of the window portion 15 is approximately 20 mm square, the thickness including the housing 10 and the circuit board 19 can be 10 mm or less. In addition, optical strains of 0.7% and 2% or less were realized. At the position of the vein of the finger 50, the depth of field was 1 mm or more, and a resolution of 30 μm could be realized.

Further, by using the incident surface 22 including the light-transmitting incident region 22a as the second reflecting surface 22, the optical path length can be bent and arranged.
Furthermore, since the near infrared ray is totally reflected in the incident region 22a, it can be used as a reflecting surface while ensuring the translucency of the incident region 22a.
Furthermore, a reflection film is formed in a region where the total reflection cannot be used on the incident surface 22 including the incident region 22a, thereby ensuring near-infrared reflection on the second reflecting surface 22 including the incident region 22a.

5 to 8 are diagrams showing another embodiment of the imaging module according to the above embodiment.
In the imaging module 30 shown in FIGS. 5 to 7, the casing 31 holds the prism 12 and the camera module 33. Next to the housing 31, LEDs 34 a to 34 f as examples of light sources are arranged.

The casing 31 is manufactured by molding a resin such as black polycarbonate, for example. The housing 31 holds the prism 12 in the holding portion 31 a, and a recess is formed in the mounting portion 31 b on the emission surface 24 side of the prism 12. As the material of the housing 31, for example, a material that absorbs light in a region from the near ultraviolet to the near infrared is preferably used. More specifically, a material that absorbs a wavelength component of light used for biometric authentication (finger authentication) is preferable. In the present embodiment, LEDs 34a to 34f that emit near-infrared rays or visible light are used as light sources, and therefore, a material that absorbs light from near-infrared to visible is preferable.
The housing 31 holds the prism 12 so that light emitted from the exit surface 24 of the prism 12 is not reflected by the housing 31 and reenters the prism 12 as stray light (unnecessary light). The inner surface (the surface on which the prism 12 faces) of the holding portion 31a may be painted. Even when the casing 31 is painted, for example, light in the region from the near ultraviolet to the near infrared is preferably absorbed, and more specifically, the wavelength component of light used for biometric authentication (finger authentication) is absorbed. It is preferred that In this Embodiment, since LED34a-34f which discharge | releases near infrared rays or visible light is employ | adopted as a light source, the coating which absorbs light from near infrared to visible is preferable.

When the prism 12 is set in the holding portion 31 a of the housing 31, the prism 12 is held at a predetermined position of the housing 31. Then, when the camera module 33 is fitted into the recess formed in the attachment portion 31b, the prism 12 and the camera module 33 are aligned.
A light passage hole 32 that is opened in a circular shape is formed in the attachment portion 31 b of the housing 31. The light passage hole 32 is concentric with the recess formed in the attachment portion 31 b and allows the light emitted from the emission surface 24 of the prism 12 to pass through and enter the camera module 33. The diameter of the light passage hole 32 is determined so that the amount of light necessary for imaging by the camera module 33 passes through the light passage hole 32. Thereby, stray light (unnecessary light) entering the camera module 33 from the prism 12 is reduced. That is, in the case where the optical system of the camera module 33 has a front diaphragm configuration, the light emitted from the emission surface 24 is allowed to pass through the light passage hole by matching the diameter of the light passage hole 32 with the diameter of the front diaphragm required for imaging. When passing through 32, the amount of light is narrowed down to the amount of light required for imaging. Therefore, the camera module 33 can omit the front aperture. When the camera module 33 has a front aperture (not shown), the diameter of the light passage hole 32 is set to be equal to or larger than the maximum diameter of the front aperture of the camera module 33, thereby enabling the aperture adjustment function of the camera module 33.

LED34a-34f has the performance equivalent to LED16 shown in FIG. 2, and the light emitting diode which emits the near infrared ray or visible light which has permeability | transmittance with respect to a biological body is used. The LEDs 34a to 34f are arranged outside a region where an optical path (not shown) connecting the incident region 22a (see FIG. 2) of the prism 12 and the imaging device 14 (see FIG. 2) of the camera module 33 is extended. For example, as shown in FIG. 5, the LEDs 34 a to 34 f have side surfaces that are not any of the incident surface 22, the first reflecting surface 21, the third reflecting surface 23, and the exit surface 24 (all refer to FIG. 2) of the prism 12. It is arranged on the side.
LED34a-34f has what has a strong directivity. For example, it is preferable that the viewing angle (full width at half maximum: emission intensity of light taken when the emission intensity becomes half of the peak value) is 45 degrees or less, and more preferably 30 degrees or less. In addition, even if it is LED with weak directivity, it can substitute by combining with a condensing lens.
The LEDs 34 a to 34 f emit light in the same direction as the normal line of the incident surface 22 of the prism 12. Thereby, since the light irradiated by the LEDs 34a to 34f is irradiated at a substantially right angle to the living body, reflection on the living body surface is reduced. In addition, you may make it irradiate light at a substantially right angle with respect to a biological body using the light conduit which is not illustrated. If a light conduit is used, the restrictions on the arrangement of LEDs are relaxed.

Also in the imaging module 40 shown in FIG. 8, the housing 41 holds the prism 12 and the camera module 43. The camera module 43 is attached to the housing 41 by fitting the concave portion 41c formed in the attachment portion 41b of the housing 41 with the convex portion 43b formed in the mount 43a of the camera module 43. 7 is different from FIG. 7 in which the camera module 33 is fitted and fixed in a recess formed in the attachment portion 31b of the body 31.
The casing 41 holds the prism 12 in the holding portion 41a. A recessed portion 41 c is formed in the mounting portion 41 b of the housing 41. Two or more recesses 41c are formed to fix the camera module 43 at a predetermined position. The light passage hole 42 is formed in the attachment portion 41b of the housing 41, which is the same as the housing 31 shown in FIG.

(Finger authentication device)
Next, the finger authentication device 100 equipped with the imaging module 1 described above will be described below with reference to the drawings.
FIG. 9 is a block diagram illustrating a configuration outline of the finger authentication device 100 as an example of the biometric authentication device. This finger authentication device 100 can be applied to personal authentication in a personal device such as a notebook PC.
As shown in FIG. 9, the finger authentication apparatus 100 according to the present embodiment includes an imaging module 1, a holding unit 51 that holds a vein pattern in advance, and a vein pattern of a finger 50 recognized by a recognition unit 26 (described later). And an authentication unit 52 that performs personal authentication by collating the vein pattern held in advance in the holding unit 51. The imaging module 1 includes an LED 16 that irradiates the finger 50 with near infrared rays, an imaging element 14 that acquires near infrared rays emitted from the finger 50, and a signal processing unit 25 that performs signal processing on an electrical signal output from the imaging element 14. And a recognition unit 26 for recognizing a vein pattern based on the image signal signal-processed by the signal processing unit 25.

The signal processing unit 25 is connected to the image sensor 14 and the recognition unit 26 and performs signal processing such as noise removal and correction on the electrical signal output from the image sensor 14.
The recognition unit 26 analyzes the image signal processed by the signal processing unit 25 to recognize and output the vein pattern of the finger 50.

The holding unit 51 is connected to the authentication unit 52. The holding unit 51 holds a plurality of vein patterns imaged in advance by the imaging module 1. Further, the stored vein pattern is output to the authentication unit 52 in response to an instruction from the authentication unit 52 described later. Furthermore, a vein pattern of a person's finger 50 newly captured by the imaging module 1 and recognized by the recognition unit 26 is acquired from the recognition unit 26 and stored in association with the personal information of the person.
The authentication unit 52 is connected to the holding unit 51 and the recognition unit 26. The authentication unit 52 performs personal authentication by comparing the vein pattern of the finger 50 imaged by the imaging module 1 with the vein pattern held in advance by the holding unit 51.

Next, a biometric authentication method using the finger authentication device 100 will be described.
A finger 50 is placed on the imaging module 1. The LED 16 irradiates the finger 50 with near infrared rays. Near-infrared rays that have passed through and diffused through the finger 50 are incident into the prism 12 from the window portion 15 of the imaging module 1.
Near-infrared light reflected from the prism 12 is incident on the imaging device 14 through the exit surface 24 and the lens unit 13 to form an image. The image sensor 14 generates an electrical signal based on the image formed and outputs it to the circuit board 19.

In the circuit board 19 that has acquired the electrical signal, the signal processing unit 25 performs noise removal and correction on the electrical signal to generate an image signal. Then, the recognition unit 26 in the circuit board 19 generates a vein pattern in the finger 50 based on the generated image signal and outputs the vein pattern to the authentication unit 52 connected to the imaging module 1. In this way, the vein pattern in the finger 50 is imaged and output by the imaging module 1.
The authentication unit 52 that has acquired the vein pattern from the imaging module 1 checks the vein pattern that the holding unit 51 holds in advance and performs personal authentication. In this way, the finger authentication device 100 performs biometric authentication.

As described above, according to the finger authentication device 100 according to the present embodiment, personal authentication is performed based on the vein pattern output from the imaging module 1 that is reduced in size and thickness. Thinning can be realized.
In the above-described embodiment, an example in which biometric authentication is applied to finger authentication using the vein pattern of the finger 50 has been described. However, the present invention is not limited to this. It can also be applied to partial blood vessel authentication.

It is an external appearance perspective view of the imaging module for finger authentication concerning this embodiment. It is sectional drawing of the imaging module shown in FIG. It is a figure for demonstrating near-infrared irradiation of the light guide in the imaging module shown in FIG. It is a figure for demonstrating the optical arrangement | positioning of the imaging module shown in FIG. It is an external appearance perspective view which shows other embodiment of an imaging module. FIG. 6 is an exploded view of the imaging module shown in FIG. 5. It is a figure for demonstrating the imaging module shown in FIG. It is a figure for demonstrating other embodiment of an imaging module. It is a block diagram which shows the structure outline | summary of the finger | toe authentication apparatus which employ | adopted the imaging module shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,30,40 ... Imaging module for finger authentication (imaging module for biometric authentication), 12 ... Prism, 13 ... Lens unit, 14 ... Imaging device, 15 ... Window part, 16 ... LED (light source), 17 ... Light guide, DESCRIPTION OF SYMBOLS 18 ... Irradiation window, 19 ... Circuit board, 20 ... Filter, 21 ... 1st reflective surface, 22 ... Incident surface, 2nd reflective surface, 22a ... Incident area | region, 23 ... 3rd reflective surface, 24 ... Output surface, 26 ... Recognizing part 31, 41 ... casing, 31a, 41a ... holding part, 31b, 41b ... mounting part, 32, 42 ... light passage hole, 33, 43 ... camera module, 34a-34f ... LED, 41c ... recessed part, 43a ... Mount, 43b ... Convex part, 50 ... Finger, 51 ... Holding part, 52 ... Authentication part, 100 ... Finger authentication device (biometric authentication device)

Claims (7)

A light source that irradiates the living body with light that passes through the living body;
A prism having an incident surface including an incident region that captures light transmitted through the living body, a plurality of reflective surfaces that reflect the light captured from the incident region, and an output surface that emits light reflected by the reflective surface; ,
A camera module having an imaging device that converts the light emitted from the exit surface of the prism into an electrical signal and outputs the electrical signal;
Said prism and the said camera module respectively disposed at a predetermined position, have a said light transmitting hole for passing the light emitted from the exit surface is formed enclosure of the prism,
The prism is configured to reflect light taken in from the incident area and reflected by the first reflecting surface so that the incident surface including the incident area is reflected as the second reflecting surface . Imaging module. The first reflection surface is disposed with a predetermined angle that reflects light taken from the incident region toward the incident region and causes total reflection in the incident region. The imaging module for biometric authentication according to 1. 3. The imaging module for biometric authentication according to claim 2, wherein the second reflective surface is formed with a reflective film in a region other than the incident region, and no reflective film is formed in the incident region.   2. The imaging module for biometric authentication according to claim 1, wherein a diameter of the light passage hole is determined so that the amount of light necessary for imaging of the camera module passes through the light passage hole. .   2. The imaging module for biometric authentication according to claim 1, wherein the casing is made of a material that absorbs light from near ultraviolet to near infrared.   The casing has at least a surface facing the prism so that light emitted from the emission surface of the prism is not reflected by the casing and reenters the prism as stray light. The imaging module for biometric authentication according to claim 1, wherein the imaging module is coated to absorb light from near ultraviolet to near infrared. A light source that irradiates the living body with light that passes through the living body;
A prism having an incident surface including an incident region that captures light transmitted through the living body, a plurality of reflective surfaces that reflect the light captured from the incident region, and an output surface that emits light reflected by the reflective surface; ,
A camera module having an imaging device that converts the light emitted from the exit surface of the prism into an electrical signal and outputs the electrical signal;
The prism and the camera module are arranged at predetermined positions, respectively, and a housing formed with a light passage hole through which light emitted from the emission surface of the prism is passed,
Recognizing means for recognizing a blood vessel pattern of a living body by analyzing an electrical signal output from the image sensor of the camera module;
Holding means for holding the blood vessel pattern of the living body in advance;
Look including an authentication means for performing personal authentication by comparing the blood vessel pattern held in the holding means and the recognized blood vessel pattern in the recognition means,
The biometric authentication device , wherein the prism is configured such that light taken in from the incident area and reflected by the first reflecting surface reflects the incident surface including the incident area as a second reflecting surface. .

Images