WO2018216662A1

WO2018216662A1 - Optical member, unevenness detection device, and fingerprint authentication device

Info

Publication number: WO2018216662A1
Application number: PCT/JP2018/019546
Authority: WO
Inventors: 賢嗣平岩
Original assignee: コニカミノルタ株式会社
Priority date: 2017-05-23
Filing date: 2018-05-21
Publication date: 2018-11-29
Also published as: JPWO2018216662A1

Abstract

Provided is an optical member that enables the detection of a high-contrast, clear uneven image. An optical member (2A) has an incidence surface (2a), which makes contact with the surface of a finger that is a subject and through which light from the surface of the finger enters, and an emission surface (2b) from which the light entering the incidence surface (2a) is emitted, and a refractive layer (3) is formed between the emission surface (2b) and an imaging element. Of the light entering the incidence surface (2a), the light that is emitted into the optical member (2A) at an angle inclined with respect to the normal-line (L1) direction of the incidence surface (2a) propagates to the emission surface (2b), and the light is emitted to the imaging element (4A) through the refractive layer 3 provided between the emission surface (2b) and the imaging element 4A; thus, the light is refracted so as to approach the normal-line direction of the imaging element (4A).

Description

Optical member, unevenness detecting device and fingerprint authentication device

The present invention relates to an optical member, an unevenness detection device, and a fingerprint authentication device.

As an unevenness detection device such as an optical fingerprint authentication device or the like, Patent Document 1 discloses a technique using a fiber optics plate (FOP) instead of a lens. In such a technique, the bundle of optical fibers in the FOP is inclined with respect to the normal direction of the light incident surface, so that light from the concave portion of the fingerprint is eliminated as much as possible and a high-contrast uneven image is taken.

JP 7-174947 A

However, in the technique described in Patent Document 1, since inclined light is also incident on the image sensor, the optical path length in the protective substrate of the image sensor is compared with light incident in the normal direction of the protective substrate of the image sensor. Becomes longer. If the optical path length from the protection substrate of the image sensor to the sensor unit is long, the light spreads there, and the concavo-convex image becomes unclear.

The present invention has been made in view of the above points, and an object thereof is to provide an optical member, a concavo-convex detection device, and a fingerprint authentication device capable of detecting a high-contrast and clear concavo-convex image.

The present invention for solving the above-described problems has the following configuration.
1. An optical member that is provided between an object and an image sensor and guides light from the surface of the object to the image sensor in order to detect an uneven pattern on the surface of the object, the surface of the object An entrance surface on which the light from the surface of the object is incident, and an exit surface from which the light incident on the entrance surface is emitted, between the exit surface and the imaging device Includes a refracting layer, and out of the light incident on the incident surface, the light emitted into the optical member at an angle inclined with respect to a normal direction of the incident surface to the output surface. Propagates and refracts the light so as to approach the normal direction of the imaging element by emitting the light to the imaging element via a refractive layer provided between the emission surface and the imaging element. Optical member.
2. The optical member is in contact with the surface of the object, the first incident surface as the incident surface on which the light from the surface of the object is incident, and the light incident on the first incident surface. A first optical member having a first emission surface to be emitted, a second incident surface on which the light emitted from the first emission surface is incident, and the second incident surface. A second optical member having a second emission surface as the emission surface from which the light is emitted, and the first optical member is configured to transmit the light incident on the first incident surface. Among them, the light emitted into the first optical member at an angle inclined with respect to the normal direction of the first incident surface is propagated to the first outgoing surface, and the second optical member is 2. The optical member according to 1, wherein the light is emitted from the second emission surface to the refractive layer.
3. The first optical member is a fiber optics plate having a plurality of optical fibers arranged in a surface direction of the first optical member, and an axial direction of the plurality of optical fibers is a normal line of the first incident surface. 3. The optical member according to 2 above, which is inclined with respect to the direction.
4). The first optical member is a louver film having a plurality of louvers arranged in one direction within the plane of the first optical member, and the plurality of louvers are in a normal direction of the first incident surface. The optical member according to 2 above, wherein a light transmitting portion that is capable of transmitting the light is formed between the pair of louvers.
5). The first optical member includes a first louver film as the louver film on the object side, and a second louver film as the louver film on the second optical member side, 5. The optical member according to 4, wherein the plurality of louvers in one louver film and the plurality of louvers in the second louver film are provided so as to intersect with each other.
6). When the refractive index of the region between the concave portion on the surface of the object and the first optical member is n1, and the refractive index of the optical member is n2, the first optical member is the first incident member. Any one of 2 to 5 above, wherein light emitted into the first optical member at an angle larger than an angle θ = arcsin (n1 / n2) with respect to the normal direction of the surface is propagated to the first emission surface An optical member according to the above.
7). The optical member according to 2, wherein the second optical member is a prism array sheet or a lens array sheet.
8). The optical member according to any one of 1 to 7, and the refractive layer and the imaging element provided on the emission surface side of the optical member, wherein the imaging element includes a protective substrate, a sensor unit, And a refractive index of the protective substrate is larger than a refractive index of the refractive layer, and the sensor unit captures light through the optical member, the refractive layer and the protective substrate as an optical image. .
9. 9. The unevenness detection apparatus according to 8, wherein the refractive layer is air existing in a gap between the optical member and the imaging element.
10. The unevenness detection apparatus according to 8 or 9, further comprising a surface light source that irradiates the surface of the object with the light.
11. 11. A fingerprint authentication device comprising: the unevenness detection device according to any one of 8 to 10; and a control unit that authenticates a fingerprint that is an uneven pattern on the surface of the object detected by the unevenness detection device.

According to the present invention, a high-contrast and clear uneven image can be detected.

(A) is sectional drawing which shows typically the fingerprint authentication apparatus which concerns on 1st embodiment of this invention, (b) is typically the fingerprint authentication apparatus which concerns on 1st embodiment of this invention. FIG. It is a perspective view showing typically the 1st optical member concerning a first embodiment of the present invention. It is a graph which shows the example of the light distribution in the 1st optical member which concerns on 1st embodiment of this invention. It is a perspective view which shows typically the 2nd optical member which concerns on 1st embodiment of this invention. It is a figure for demonstrating propagation of the light in the fingerprint authentication apparatus which concerns on 1st embodiment of this invention. It is a perspective view which shows typically the 1st optical member which concerns on 2nd embodiment of this invention. It is a figure for demonstrating the propagation of the light in the fingerprint authentication apparatus which concerns on 2nd embodiment of this invention. It is a perspective view which shows typically the 1st optical member which concerns on 3rd embodiment of this invention. It is a perspective view which shows typically the 2nd optical member which concerns on 4th embodiment of this invention. It is a perspective view which shows typically the 2nd optical member which concerns on 5th embodiment of this invention. (A) is sectional drawing which shows typically the fingerprint authentication apparatus which concerns on 6th embodiment of this invention, (b) is typically the fingerprint authentication apparatus which concerns on 6th embodiment of this invention. FIG. (A) is sectional drawing which shows typically the fingerprint authentication apparatus which concerns on 7th embodiment of this invention, (b) is typically the fingerprint authentication apparatus which concerns on 7th embodiment of this invention. FIG. It is sectional drawing which shows typically the fingerprint authentication apparatus which concerns on 8th embodiment of this invention.

Embodiments of the present invention will be described in detail with reference to the drawings, taking as an example the case where the uneven pattern detection apparatus of the present invention is applied to a fingerprint authentication apparatus. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted.

As shown in FIG. 1, a fingerprint authentication device 1A according to a first embodiment of the present invention is an optical authentication device that detects a fingerprint as a concavo-convex pattern on the surface of an object. A layer 3, an image sensor 4 A, a control unit 5, and a notification unit 6 are provided.

<Optical member>
The optical member 2A is a member that guides light from the finger F (finger, for example, index finger), which is an object, to the image sensor 4A, and includes an incident surface 2a and an output surface 2b. The incident surface 2a is a flat surface that comes into contact with the surface of the finger F and on which light from the surface of the finger F is incident. The exit surface 2b is an uneven surface from which light incident on the entrance surface 2a is emitted.

Here, the refractive index of the finger F, which is the object, is about 1.43. Since the finger F is a scatterer with a high diffusivity, the light incident on the finger is emitted from the convex portion F1 and the concave portion F2 of the fingerprint with almost uniform intensity from all directions. The light from the convex portion F1 is refracted and emitted from the finger F (refractive index: about 1.43) into the first optical member 10A (refractive index: 1.55 to 1.8). A component having a large angle with respect to the normal line L1 (see FIG. 5) is included (see FIG. 3). On the other hand, the light from the recess F2 enters the first optical member (refractive index: 1.55 to 1.8) from the finger F (refractive index: about 1.43) through the air (refractive index: 1). Since the light is refracted and emitted, a component having a large angle with respect to the direction of the normal L1 (see FIG. 5) of the incident surface 2a is not included (see FIG. 3).

The optical member 2A propagates the light emitted into the optical member 2A to the emission surface 2b at an angle inclined with respect to the direction of the normal L1 (see FIG. 5) of the incidence surface 2a out of the light incident on the incidence surface 2a. Then, by emitting the light to the image sensor 4A through the refractive layer 3, the light is refracted in the normal L2 direction (see FIG. 5) of the incident surface of the image sensor 4A. The optical member 2A includes a first optical member 10A and a second optical member 20A.

≪First optical member≫
As shown in FIG. 2, the first optical member 10A includes a first incident surface 10a as the incident surface 2a and a first emission surface 10b. The first exit surface 10b is a plane from which light incident on the first entrance surface 10a is emitted. In the present embodiment, the first incident surface 10a and the first emission surface 10b are parallel to each other. 10 A of 1st optical members are the said 1st optical members in the angle which inclines with respect to the normal L1 (refer FIG. 5) direction of the 1st incident surface 10a among the light which injected into the 1st incident surface 10a. The light emitted into 10A propagates to the first emission surface 10b.

As shown in FIG. 3, the light from the fingerprint projection F1 of the finger F includes light of a component having a large incident angle (an angle with respect to the normal L1 (see FIG. 5)) on the first incident surface 10a. Thus, the light of such components suitably propagates in the first optical member 10A. Here, of the light from the convex portion F1, light having a component with a small emission angle from the first incident surface 10a does not propagate through the first optical member 10A. On the other hand, most of the light from the concave portion F2 of the fingerprint of the finger F is light having a component with a small emission angle from the first incident surface 10a (angle with respect to the normal L1 (see FIG. 5)). It hardly propagates in the optical member 10A. Thereby, the first optical member 10A actively propagates the light from the convex portion F1 of the fingerprint of the finger F and eliminates the light from the concave portion F2 of the fingerprint of the finger F as much as possible. The image can be propagated to the first exit surface 10b. Here, assuming that the maximum value of the emission angle θ of light from the concave portion F2 from the first incident surface 10a into the first optical member 10A (the angle with respect to the normal L1 of the first incident surface 10a) is θ _F2MAX. The θ _F2MAX is determined by the refractive index n1 between the fingerprint recess F2 of the finger F and the first optical member 10A (that is, the refractive index of air) and the refractive index n2 of the first optical member 10A. It is determined as follows.
θ _F2MAX = arcsin (n1 / n2)

As shown in FIG. 2, in the present embodiment, the first optical member 10A is a fiber optics plate (FOP), and a plurality of optical fibers arranged in the surface direction of the first optical member 10A. 11. The plurality of optical fibers 11 extend from the first incident surface 10a to the first emission surface 10b, and the axial direction of the plurality of optical fibers 11 is the normal L1 of the first incident surface 10a (see FIG. 5). It is inclined with respect to the direction by an angle α (see FIG. 5). The first optical member 10 A includes a core 12 and a clad 13 that constitute the optical fiber 11, and a light absorber 14.

The core 12 has an inclined cylindrical shape and is made of a material capable of propagating light. The clad 13 has an inclined cylindrical shape that covers the outer peripheral surface of the core 12, and is formed of a light-transmitting material having a refractive index smaller than that of the core 12. The light absorber 14 is provided so as to fill a space between the plurality of optical fibers 11 and is formed of a material capable of absorbing light.

The first optical member 10A propagates only the light totally reflected between the core 12 and the clad 13 out of the light incident on the cores 12 of the plurality of optical fibers 11 on the first incident surface 10a. The light exits from the exit surface 10b. In other words, the light incident on the clad 13 and the light absorber 14 on the first incident surface 10a and the light that has entered the core 12 but is not totally reflected between the core 12 and the clad 13 are incident on the light absorber 14. It is absorbed and does not exit from the first exit surface 10b.

Such total reflection can be realized by appropriately setting the angle in the axial direction of the optical fiber 11 with respect to the normal direction of the first incident surface 10a and the difference in refractive index between the core 12 and the clad 13.

Generally, the refractive index of the core 12 is about 1.55 to 1.80, and the refractive index of the clad 13 is 1.55 or less. Further, the axial direction of the optical fiber 11 with respect to the normal direction of the first incident surface 10 a can be arbitrarily set by the cut angle of the bundle of optical fibers 11. For example, the refractive index of the core 12 is about 1.55 to 1.70, the refractive index of the cladding 13 is 1.55 or less, and the optical fiber 11 is in the direction of the normal L1 (see FIG. 5) of the first incident surface 10a. The angle α in the axial direction (see FIG. 5) is preferably set to 30 degrees or more and 60 degrees or less.

≪Second optical member≫
As shown in FIG. 4, the second optical member 20A is provided between the first optical member 10A and the refractive layer 3, and the second incident surface 20a and the second as the exit surface 2b. And an emission surface 20b. The second incident surface 20a is a plane on which light emitted from the first emission surface 10b of the first optical member 10A is incident. The second entrance surface 20a is in contact (surface contact) with the first exit surface 10b of the first optical member 10A, thereby preventing total reflection on the first exit surface 10b. The second emission surface 20 b is an uneven surface from which light incident on the second incidence surface is emitted to the refractive layer 3. The refractive index of the second optical member 20A may be a value close to the first optical member 10A (more specifically, the refractive index of the core 12), and is preferably 1.55 to 1.80.

If there is no second optical member 20A, total reflection occurs in part of the light between the exit surface 10b of the first optical member 10A and the refractive layer 3. Here, part of the totally reflected light is mainly light having an angle larger than _θF2MAX . That is, light having an angle larger than θ _F2MAX possessed only by the convex portion F1 of the fingerprint is not extracted by the refractive layer 3 due to total reflection, and is absorbed by the light absorber 14. As a result, the difference in brightness between the convex portion F1 and the concave portion F2 of the fingerprint of the finger F that is the object is reduced. In other words, the second optical member 20A prevents total reflection from occurring on the exit surface of the first optical member 10A, and _takes out light having an angle larger than θ _F2MAX to the refractive layer 3, thereby _achieving high contrast. Can be propagated to the refractive layer 3.

In the present embodiment, the second optical member 20A is a prism array sheet, and includes a sheet portion 21 and a plurality of prism portions 22 arranged on the imaging element 4A side of the sheet portion 21. The plurality of prism portions 22 have a triangular prism shape, and one prism portion 22 extends in a direction intersecting with the inclination direction of the optical fiber 11. That is, the prism portion 22 emits the light from the first optical member 10A to the refractive layer 3 without being totally reflected on the emission surface 2b, that is, the second emission surface 20b. The thickness of the second optical member 20A is desirably 200 [μm] or less. As the second optical member 20A, for example, 3M BEF (Brightness Enhancement Film) or the like can be suitably used.

<Refractive layer>
As shown in FIG. 1, the refractive layer 3 is provided between the second optical member 20A and the image sensor 4A, and the light emitted from the exit surface 2b, that is, the second exit surface 20b, is converted into the image sensor. The light is refracted in the normal direction of the incident surface of 4A. The refractive index of the refractive layer 3 is set to be smaller than the refractive index of the protective substrate 80 of the image sensor 4A, and it is desirable that the difference from the refractive index of the protective substrate 80 is large. Examples of the refractive layer 3 include silicon rubber having a refractive index of about 1.4, contact liquid (matching oil) having a refractive index of about 1.4 to 1.8, and air having a refractive index of about 1. Then, air with a low refractive index is most desirable.

<Image sensor>
The imaging element 4A is for detecting irregularities on the surface of the finger F, that is, fingerprints, by receiving light from the finger F that is an object through the optical member 2A and the refractive layer 3. The image sensor 4A includes a support substrate 30, TFTs (Thin Film Transistor) 40, a pixel electrode 50, a photoelectric conversion layer (for example, an organic photoelectric conversion layer) 60, a counter electrode 70, and a protective substrate that are sequentially formed on the support substrate 30. 80. The TFT 40, the pixel electrode 50, the photoelectric conversion layer (for example, organic photoelectric conversion layer) 60, and the counter electrode 70 constitute a sensor unit that captures light from the finger F as an optical image.

As shown in FIG. 5, in the fingerprint authentication device 1 A according to the first embodiment of the present invention, light from the surface of the finger F that is the target is incident surface 2 a (first incident surface 10 a), first Core 12 of optical member 10A, first exit surface 10b, second entrance surface 20a, sheet portion 21 and prism portion 22 of second optical member 20A, exit surface 2b (second exit surface 20b) and refraction. The light enters the protective substrate 80 of the image sensor 4 A through the layer 3. The protective substrate 80 is a transparent substrate formed of resin, glass or the like. The entrance surface and the exit surface of the protective substrate 80 are parallel to the first entrance surface 10a and the first exit surface 10b of the first optical member 10A and the second entrance surface of the second optical member 20A, respectively. .

<Control unit>
As shown in FIG. 1, the control unit 5 includes a CPU (Central Processing Unit), a ROM (Read-Only Memory), a RAM (Random Access Memory), an input / output circuit, and the like, and a fingerprint image stored in advance. Are used to authenticate the unevenness of the finger F detected by the image sensor 4A, that is, the fingerprint image, and output the authentication result to the notification unit 6.

The notification unit 6 is a display unit (for example, a monitor) that displays an authentication result by the control unit 5 and / or a voice output unit (speaker) that outputs the authentication result by the control unit 5 by voice.

<Propagation of light>
As shown in FIG. 5, the light from the finger F, which is the object, is emitted from the first incident surface 10a into the first optical member 10A at an angle inclined with respect to the normal L1, and the first optical member It propagates through the core 12 of the member 10A and exits from the first exit surface 10b. The light emitted from the first emission surface 10b is emitted from the second incidence surface 20a into the second optical member 20A, propagates through the second optical member 20A, and is refracted from the second emission surface 20b. 3 is refracted and emitted. The light emitted from the second emission surface 20b to the refractive layer 3 propagates through the refractive layer 3 and is emitted while being refracted to the protective substrate 80 of the image sensor 4A. Here, since the refractive index of the protective substrate 80 is larger than the refractive index of the refractive layer 3, the first optical member 10A is inclined with respect to the normal L1 of the first incident surface 10a of the first optical member 10A. The light emitted inward is refracted so that its traveling direction approaches the normal L2 direction of the incident surface of the protective substrate 80.

The optical member 2A and the fingerprint authentication device 1A according to the first embodiment of the present invention propagate light out of the light from the object F at an angle inclined with respect to the incident surface 2a and extract it to the refractive layer 3, Since the light is refracted in the direction of the normal L2 of the image sensor 4A using the refraction layer 3, a high-contrast uneven image of the target finger F is obtained, and the optical path length of the light from the protective substrate 80 to the sensor unit It is possible to obtain a clear concavo-convex image by shortening.

In addition, since the optical member 2A and the fingerprint authentication device 1A include the first optical member 10A and the second optical member 20A, the degree of freedom in design is improved and the emission surface 2b is easily formed.

Also, the optical member 2A and the fingerprint authentication device 1A can easily realize the function as the first optical member 10A because the first optical member 10A is an FOP.

In addition, the optical member 2A and the fingerprint authentication device 1A are configured so that the first incident surface has an angle larger than θ _F2MAX = arcsin (n1 / n2) among the light incident on the first incident surface 10a by the first optical member 10A. Since only the light emitted from 10a into the first optical member 10A is propagated, most of the light from the fingerprint recess F2 of the target finger F cannot be propagated. The difference in brightness between the part F1 and the recessed part F2 can be increased, and a high-contrast uneven image of the finger F that is the object can be obtained.

Also, the optical member 2A and the fingerprint authentication device 1A can easily realize the function as the second optical member 20A because the second optical member 20A is a prism array sheet.

Further, since the refraction layer 3 is air, the fingerprint authentication device 1A refracts the light using the refraction layer 3 so that the traveling direction thereof is closer to the normal L2 direction of the image sensor 4A, and the optical path length of the light is increased. It can suppress and can obtain a clear uneven image.

<Second Embodiment>
Next, a fingerprint authentication device according to the second embodiment of the present invention will be described focusing on differences from the fingerprint authentication device 1A according to the first embodiment. As shown in FIGS. 6 and 7, the optical member 2B of the fingerprint authentication device 1B according to the second embodiment of the present invention includes a first optical member 10B instead of the first optical member 10A.

≪First optical member (first louver film) ≫
The first optical member 10B is a louver film, and fills the space between the pair of louvers 15 and a plurality of louvers (light absorbers) 15 arranged in one direction within the surface of the first optical member 10B. And a light transmitting portion 16 provided in the. The louver 15 has an inclined long plate shape and is made of a material that can absorb light. The light transmission part 16 is formed of a material that can transmit light.

The first optical member 10B propagates only light incident at an angle that does not hit the louver 15 that is a light absorber, out of the light incident on the light transmitting portion 16 on the first incident surface 10a, and the first emission. The light exits from the surface 10b. In other words, the light incident on the louver 15 on the first incident surface 10a and the light incident on the light transmitting portion 16 but hitting the louver 15 are absorbed by the louver 15 which is a light absorber, and are emitted from the first exit surface. It does not radiate | emit from the surface 10b.

The inclination angle of the louver 15 with respect to the normal direction of the first incident surface 10a eliminates light from the concave portion of the object (finger) F as much as possible, and positively emits light from the convex portion of the object (finger) F. It is desirable to set the propagation angle, for example, 30 degrees or more and 60 degrees or less.

The first optical member 10B can be formed of silicon resin, polycarbonate resin, polystyrene resin, acrylic resin, polyvinyl chloride resin, or the like. That is, the first optical member 10B can be made thinner and thinner than the first optical member 10A (see FIG. 2).

In the fingerprint authentication device 1B and the optical member 2B according to the second embodiment of the present invention, since the first optical member 10B is a louver film, it can be realized at a lower cost and thinner than the FOP.

<Third embodiment>
Next, a fingerprint authentication device according to the third embodiment of the present invention will be described focusing on differences from the fingerprint authentication device 1A according to the second embodiment. As shown in FIG. 8, the optical member 2C of the fingerprint authentication device 1C according to the third embodiment of the present invention includes a first optical member 10C in addition to the first optical member 10B.

≪First optical member (second louver film) ≫
The first optical member 10 C is a louver film that fills a space between the pair of louvers 15 and a plurality of louvers (light absorbers) 15 arranged in one direction within the plane of the first optical member 10 C. And a light transmitting portion 16 provided in the. The first optical member 10C is provided between the first optical member 10B and the second optical member 20A (see FIG. 1). The extending direction X1 of the plurality of louvers 15 in the first optical member 10B and the extending direction X2 of the plurality of louvers 15 in the first optical member 10C intersect each other (in the present embodiment, they are orthogonal in a plan view). As provided). The entrance surface 10a and the exit surface 10c of the first optical member 10B and the entrance surface 10d and the exit surface 10b of the first optical member 10C are parallel to each other, and the exit surface 10c and the entrance surface 10d are in surface contact. .

That is, in the fingerprint authentication device 1B according to the second embodiment described above, the light that is inclined in the extending direction X1 of the first optical member 10B and is incident on the first optical member 10B is normal to the incident surface 10a. The light emitted into the first optical member 10B at a large angle with respect to the L1 (see FIG. 5) direction and the light emitted into the first optical member 10B at a small angle are not absorbed by the louver 15 without being absorbed by the louver 15. The light exits from the exit surface 10b of the optical member 10B. Therefore, the concave / convex image (fingerprint image) of the finger F obtained by the fingerprint authentication device 1B according to the second embodiment is also stretched because light from the concave portion F2 of the fingerprint is also extracted from the exit surface in the stretching direction X1. In the direction X1, the contrast between the convex portion F1 and the concave portion F2 of the fingerprint becomes small, resulting in low contrast.

On the other hand, in the fingerprint authentication device 1C according to the third embodiment of the present invention, the louver 15 of the first optical member 10C is in the normal direction of the incident surface 10d in the extending direction X1 (the normal line L1 in FIG. 5). The light emitted into the first optical member 10C at a small angle with respect to the same direction) can be absorbed. That is, the fingerprint authentication device 1C can absorb most of the light from the concave portion F2 of the fingerprint (here, out of the light from the convex portion F1 of the fingerprint, the normal direction of the incident surfaces 10a and 10d (see FIG. 5 is also absorbed, but it is emitted at a large angle with respect to the normal direction of the incident surfaces 10a and 10d (the same direction as the normal L1 in FIG. 5). The incident light is emitted from the emission surface), and the difference in brightness between the convex portion F1 and the concave portion F2 of the fingerprint can be increased also in the extending direction X1, and an uneven image of the finger F with high contrast can be obtained.

The fingerprint authentication device 1C and the optical member 2C according to the third embodiment of the present invention have high contrast in both the stretching directions X1 and X2 by using two relatively inexpensive and thin

optical members

10B and 10C. An uneven image (fingerprint image) of the finger F can be obtained.

<Fourth embodiment>
Next, a fingerprint authentication device according to the fourth embodiment of the present invention will be described focusing on differences from the fingerprint authentication device 1A according to the first embodiment. As shown in FIG. 9, the optical member 2D of the fingerprint authentication device 1 according to the fourth embodiment of the present invention includes a second optical member 20D instead of the second optical member 20A.

The second optical member 20D is a lens array sheet, and includes a sheet portion 21 and a plurality of hemispherical portions (lens portions) 23 two-dimensionally arranged on the image pickup element 4A (see FIG. 1) side of the sheet portion 21. . In the second optical member 20D, the hemispherical part 23 realizes the same function as the prism part 22.

In the fingerprint authentication device 1D and the optical member 2D according to the fourth embodiment of the present invention, since the second optical member 20D is a lens array sheet, the function as the second optical member 20D can be easily realized. it can.

<Fifth embodiment>
Next, a fingerprint authentication device according to the fifth embodiment of the present invention will be described focusing on differences from the fingerprint authentication device 1A according to the first embodiment. As shown in FIG. 10, the optical member 2E of the fingerprint authentication device 1E according to the fifth embodiment of the present invention includes a second optical member 20E instead of the second optical member 20A.

The second optical member 20E is a prism array sheet, and includes a sheet portion 21 and a plurality of quadrangular pyramid portions 24 two-dimensionally arranged on the image pickup element 4A (see FIG. 1) side of the sheet portion 21. . In the second optical member 20E, the quadrangular pyramid portion 24 achieves the same function as the prism portion 22.

In the fingerprint authentication device 1E and the optical member 2E according to the fifth embodiment of the present invention, since the second optical member 20E is a prism array sheet, the function as the second optical member 20E can be easily realized. it can.

<Sixth embodiment>
Next, a fingerprint authentication device according to the sixth embodiment of the present invention will be described focusing on differences from the fingerprint authentication device 1A according to the first embodiment. As shown in FIG. 11, the fingerprint authentication device 1F according to the sixth embodiment of the present invention includes a plurality of surface light sources 90. The plurality of surface light sources 90 are, for example, organic EL panels, and are provided so as to surround the finger F that is the object from three directions in plan view, and irradiate the finger F that is the object with light. In FIG. 11, a part of the configuration of the image sensor 4A is not shown.

Since the fingerprint authentication device 1F according to the sixth embodiment of the present invention includes the surface light source 90, it is possible to irradiate the finger F with the light amount unevenness suppressed, and to detect the uneven image without unevenness. Can do. In addition, since the fingerprint authentication device 1F can detect a concavo-convex image without unevenness, it is possible to realize quick fingerprint authentication with reduced power consumption.

<Seventh embodiment>
Next, a fingerprint authentication device according to the seventh embodiment of the present invention will be described focusing on differences from the fingerprint authentication device 1A according to the sixth embodiment. As shown in FIG. 12, in the fingerprint authentication device 1G according to the seventh embodiment of the present invention, the plurality of surface light sources 90 are interposed between the finger F, which is the object, and the first optical member 10A. ing. In other words, the plurality of surface light sources 90 are provided at a portion where the finger F that is an object contacts. In FIG. 12, a part of the configuration of the image sensor 4A is not shown.

In the fingerprint authentication device 1G according to the seventh embodiment of the present invention, since the surface light source 90 is interposed between the finger F and the first optical member 10A, the surface light source 90 is interposed between the finger F and air. Therefore, light is emitted in direct contact with each other, reflection and absorption between the surface light source 90 and the air can be eliminated, and a reduction in power efficiency can be prevented.

<Eighth embodiment>
Next, a fingerprint authentication device according to the eighth embodiment of the present invention will be described focusing on differences from the fingerprint authentication device 1F according to the sixth embodiment. As shown in FIG. 13, a fingerprint authentication device 1H according to an eighth embodiment of the present invention includes an image sensor 4H in which a plurality of surface light sources 90 are integrated. That is, the surface light source 90 is formed between the support substrate 30 and the protective substrate 80 around the TFT (Thin Film Transistor) 40, the pixel electrode 50, the photoelectric conversion layer 60, and the counter electrode 70. The counter electrode 91, the organic light emitting layer 92, and the transparent electrode 93 are provided in order. The organic light emitting layer 92 emits light when voltage is applied by the counter electrode 91 and the transparent electrode 93.

In the fingerprint authentication device 1H according to the eighth embodiment of the present invention, since the plurality of surface light sources 90 are integrated with the image sensor 4H, it is possible to reduce the thickness.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably. For example, the second

optical members

20A, 20D, and 20E may be omitted by changing the shape of the emission surface of the first

optical members

10A, 10B, and 10C to a prism array shape or a lens array shape. .

1A ~ 1H Fingerprint authentication device (Unevenness detection device)
2A to 2E Optical member 3

Refractive layer

4A, 4H Image sensor 10A First optical member 10B First optical member (first louver film)
10C

Second louver film

20A, 20D, 20E Second optical member 80 Protective substrate 90 Surface light source F Finger (object)

Claims

An optical member that is provided between the object and the image sensor and guides light from the surface of the object to the image sensor in order to detect an uneven pattern on the surface of the object;
An incident surface that is in contact with the surface of the object and on which the light from the surface of the object is incident;
An exit surface from which the light incident on the entrance surface is emitted;
Have
Between the exit surface and the imaging device, a refractive layer is configured,
Of the light incident on the incident surface, the light emitted into the optical member at an angle inclined with respect to the normal direction of the incident surface is propagated to the output surface, and the light is transmitted to the output surface and the light An optical member that refracts the light so as to approach the normal direction of the image sensor by emitting the image to the image sensor via a refractive layer provided between the image sensor and the image sensor.
The optical member is
A first incident surface as the incident surface on which the light from the surface of the object is incident and is in contact with the surface of the object, and the first light incident on the first incident surface is emitted. A first optical member having:
A second incident surface on which the light emitted from the first emission surface is incident, and a second emission surface as the emission surface from which the light incident on the second incident surface is emitted. A second optical member having;
With
The first optical member emits light into the first optical member at an angle inclined with respect to the normal direction of the first incident surface out of the light incident on the first incident surface. Propagating light to the first exit surface;
The optical member according to claim 1, wherein the second optical member emits the light from the second emission surface to the refractive layer.
The first optical member is a fiber optics plate having a plurality of optical fibers arranged in the surface direction of the first optical member,
The optical member according to claim 2, wherein an axial direction of the plurality of optical fibers is inclined with respect to a normal direction of the first incident surface.
The first optical member is a louver film having a plurality of louvers arranged in one direction in the plane of the first optical member,
The plurality of louvers are light absorbing portions that are inclined with respect to the normal direction of the first incident surface,
The optical member according to claim 2, wherein a light transmission part capable of transmitting the light is formed between the pair of louvers.
The first optical member includes a first louver film as the louver film on the object side, and a second louver film as the louver film on the second optical member side,
The optical member according to claim 4, wherein the plurality of louvers in the first louver film and the plurality of louvers in the second louver film are provided so as to intersect with each other.
When the refractive index of the region between the concave portion on the surface of the object and the first optical member is n1, and the refractive index of the optical member is n2, the first optical member is the first incident member. 6. The light emitted into the first optical member at an angle larger than an angle θ = arcsin (n1 / n2) with respect to the normal direction of the surface is propagated to the first emission surface. The optical member as described in any one of these.
The optical member according to claim 2, wherein the second optical member is a prism array sheet or a lens array sheet.
The optical member according to any one of claims 1 to 7,
The refractive layer and the image sensor provided on the exit surface side of the optical member;
With
The imaging device includes a protective substrate and a sensor unit,
The refractive index of the protective substrate is larger than the refractive index of the refractive layer,
The sensor unit is a concavo-convex detection device that captures light through the optical member, the refractive layer, and the protective substrate as an optical image.
The unevenness detecting device according to claim 8, wherein the refractive layer is air existing in a gap between the optical member and the imaging device.
The unevenness detection apparatus according to claim 8 or 9, further comprising a surface light source that is provided on the incident surface and irradiates the surface of the object with the light.
The unevenness detection device according to any one of claims 8 to 10,
A controller that authenticates a fingerprint, which is a concavo-convex pattern on the surface of the object, detected by the concavo-convex detection device;
A fingerprint authentication device comprising: