JPH06195450A - Fingerprint image input device - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a fingerprint image input device, and an object thereof is to replace a fingerprint image input face plate. In a fingerprint image input device including a parallel plate-shaped or prism-shaped transparent substrate and a fingerprint image input face plate having a fingerprint image input face, a transparent substrate and a fingerprint image input face plate are transparent. A matching material layer that is in optical contact with the substrate and the fingerprint image input face plate is interposed, and the optical matching material layer is the information from the fingerprint that propagates in the fingerprint input face plate at a critical angle or more with respect to air. After the light propagates through the optical matching material layer without being totally reflected at the interface between the fingerprint input face plate and the optical matching material layer, the light is not totally reflected at the interface between the optical matching material layer and the transparent substrate, and inside the transparent substrate. The fingerprint image input face plate is detachable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fingerprint image input device in which a fingerprint image input face plate is removable. There is a fingerprint collation system as a system for identifying an individual. In this system, since the fingerprint is handled as an image, a fingerprint image input device for converting the fingerprint into image data and inputting the image data is required.

[0002]

2. Description of the Related Art FIG. 1 shows an example of a conventional fingerprint image input device.
A device having a configuration as shown in 0 is known. In FIG. 10, 10 is a transparent flat plate, which is a glass plate. Reference numeral 11 is a light guide plate fixed to the transparent flat plate 10. The light guide plate 11 is
It is a glass plate. The mirror 1 is provided on one side 12 of the light guide plate 11.
4 is bonded, and a spherical lens 18 is provided on the other side 16 via a diaphragm 17. 20 is a spherical lens 1
It is a mirror that reflects the light from 8 to the image pickup device 22 composed of a CCD. The finger 24 placed on the transparent flat plate 10 is irradiated with light as illustrated.

When a finger is pressed against the fingerprint image input surface 10S of the transparent flat plate 10, the convex portion of the fingerprint of the concavo-convex pattern contacts the fingerprint image input surface 10S, but the concave portion does not contact. When light is applied to the fingerprint image input surface 10S against which the finger 24 is pressed,
It is reflected and scattered on the finger surface and inside. The scattered light from the concave portion of the finger 24 once passes through the air and enters the transparent flat plate 10,
There is no component that is totally reflected and propagates in the transparent flat plate 10.

However, the reflected / scattered light from the convex portion is directly incident on the transparent flat plate 10 from the finger 24 as a spherical wave, and a part of the light satisfies the condition of total reflection in the transparent flat plate 10 and is reflected in the transparent flat plate 10. Repeats total reflection and propagates. This total reflection component is reflected by the mirror 14 to form an image on the image pickup device 22 via the diaphragm 17, the spherical lens 18, and the mirror 20, so that the image of the ridge pattern of the convex portion formed on the finger 24 (that is, , Fingerprint image) can be obtained.

[0005]

Although a fingerprint image can be taken with only the above-mentioned device configuration, when a dry finger is placed on the transparent flat plate 10, optical contact between the finger and the fingerprint image input surface 10S is achieved. As a result, the fingerprint pattern may be blurred, which may affect the matching performance. As a means for avoiding this, there is also a device in which the fingerprint image input surface 10S is coated with an elastic film to improve the optical contact between the finger and the fingerprint image input surface 10S.

However, since the elastic film has a lower strength than glass, there is a possibility that the elastic film may be damaged or clouded in view of long-term use. Such an obstacle appears in the picked-up fingerprint image, resulting in deterioration of fingerprint collation performance.

The present invention has been made in view of the above technical problems, and an object thereof is to provide a fingerprint image input device capable of exchanging a fingerprint image input face plate.

[0008]

FIG. 1 shows a principle block diagram of the invention according to claims 1 to 3. FIG. 2 shows a block diagram of the principle of the invention according to claim 4.

The invention according to claim 1 is, as shown in FIG. 1, a fingerprint image formed by including a parallel plate-shaped or prism-shaped transparent substrate 1 and a fingerprint image input face plate 2 having a fingerprint image input face. In the input device, a matching material layer 3 that is in optical contact with the transparent substrate 1 and the fingerprint image input face plate 2 is provided between the transparent substrate 1 and the fingerprint image input face plate 2, In the optical matching material layer 3, information light from a fingerprint propagating in the fingerprint input face plate 2 at a critical angle with respect to air or more is totally reflected at an interface between the fingerprint input face plate 2 and the optical matching material layer 3. After being propagated through the optical matching material layer 3 without being reflected, a refractive index satisfying the condition of propagating in the transparent substrate 1 without being totally reflected at the interface between the optical matching material layer 3 and the transparent substrate 1 is further provided. And has the fingerprint image input face plate 2 Characterized in that the disengageable.

According to a second aspect of the present invention, as shown in FIG. 1, in the fingerprint image input device according to the first aspect, a space between the transparent substrate 1 and the fingerprint image input face plate 2 is sealed around its periphery. An optical matching liquid is filled in the formed sealed space, and the information light from the fingerprint propagating in the fingerprint input face plate 2 at a critical angle or more with respect to air in the optical matching liquid is the fingerprint input face plate. 2 propagates through the optical matching liquid layer 3 without being totally reflected at the interface between the optical matching liquid layer 3 and the optical matching liquid layer 3, and then is transparent without being totally reflected at the interface between the optical matching liquid layer 3 and the transparent substrate 1. It is characterized by having a refractive index that satisfies the condition of propagating in the substrate 1.

According to a third aspect of the invention, as shown in FIG. 1, in the fingerprint image input device according to the first aspect, the transparent substrate 1 and the fingerprint image input face plate 2 are provided between the transparent substrate 1 and the fingerprint image input face plate 2. An optical matching material layer 4 capable of being hardened after being optically brought into close contact with the fingerprint image input face plate 2 is interposed, and the optical matching material layer 4 has a critical angle with respect to air inside the fingerprint input face plate 2. The information light from the fingerprint propagating as described above propagates through the optical matching material layer 4 without being totally reflected at the interface between the fingerprint input face plate 2 and the optical matching material layer 4, and then the optical matching material. The fingerprint image input face plate 2 is detachable, having a refractive index that satisfies the condition of propagating in the transparent substrate 1 without being totally reflected at the interface between the layer 4 and the transparent substrate 1.

According to a fourth aspect of the invention, as shown in FIG. 2, in the fingerprint image input device according to the first and third aspects, the transparent substrate 1 and the fingerprint image input face plate 2 are optically closely attached. The optical matching material layer 5 is coated on either the transparent substrate 1 or the fingerprint image input face plate 2, and the optical matching material layer 5 allows the inside of the fingerprint input face plate 2 to have a critical angle with respect to air. The information light from the fingerprint propagating as described above is not totally reflected at the interface between the fingerprint input face plate 2 and the optical matching material layer 5, and the optical matching material layer 5
Of the optical matching material layer 5 and the transparent substrate 1 and further has a refractive index satisfying a condition of propagating in the transparent substrate 1 without being totally reflected at the interface between the optical matching material layer 5 and the transparent substrate 1. The fingerprint image input face plate 2 is provided with a transparent substrate 1 and a fingerprint image input face plate 2 each having a reference numeral 5, and a fixing jig 7 for fixing the transparent substrate 1 and the fingerprint image input face plate 2 to a housing 6 of the fingerprint image input device. It is characterized by making it detachable.

[0013]

The invention according to claim 1 has optical adhesion between the transparent substrate 1 and the fingerprint image input face plate 2 to the transparent substrate 1 and the fingerprint image input face plate 2. Since the transparent substrate 1 and the fingerprint image input face plate 2 are sandwiched by the optical matching material layers 3 having the above-described values, the fingerprint image input face plate 2 can be easily transparent. It can be detached from the substrate 1. Therefore, since the fingerprint image input face plate 2 can be easily replaced, the fingerprint collation device can be used as quickly as possible.

The invention of claim 2 is characterized in that the optical matching material layer 3 of the invention of claim 1 is made of an optical matching liquid. The same effect as the invention according to claim 1 is obtained.

According to a third aspect of the invention, the optical matching material layer 3 of the first aspect of the invention has optical adhesion to the transparent substrate 1 and the fingerprint image input face plate 2, and The optical matching material layer 4 is curable and has a refractive index with respect to the transparent substrate 1 and the fingerprint image input face plate 2 described above. The effect is similar to the effect of the invention according to claim 1.

According to a fourth aspect of the present invention, the optical matching material layer 3 of the first aspect has optical adhesion to the transparent substrate 1 and the fingerprint image input face plate 2. An optical matching material layer 5 coated on either the transparent substrate 1 or the fingerprint image input face plate 2 and having a refractive index with respect to the transparent substrate 1 and the fingerprint image input face plate 2 is the transparent substrate. 1 and the fingerprint image input face plate 2
Is fixed to the housing 6 of the fingerprint image input device by a fixing jig 7. The effect is similar to the effect of the invention according to claim 1.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an embodiment of the invention according to claims 1 and 2. In this figure, the same reference numerals as the reference numerals given to the constituent elements of the conventional fingerprint image input device shown in FIG. 10 indicate the same constituent elements, and therefore a detailed description thereof will not be given. Do not repeat. Two
Reference numeral 8 is a sealing material that seals between the transparent flat plate 10 and the light guide plate 11. The liquid matching material 30 is filled in the sealed space formed by sealing the space between the transparent flat plate 10 and the light guide plate 11 with the sealing material 28. The sealing prevents the liquid matching material 30 from volatilizing. The matching material 30 is
The refractive index is almost the same as that of glass, and the adhesiveness between the transparent flat plate 10 and the light guide plate 11 is obtained, but the adhesiveness is not provided. Further, it is desirable that it is non-volatile. The transparent flat plate 10 may be a plastic material or the like. Depending on the materials of the transparent flat plate 10 and the light guide plate 11, the refractive index of the liquid matching material 30 needs to be a value sufficient to guide the fingerprint image light to the spherical lens 18. The condition of the refractive index that the optical matching material (layer) must have is that the information light from the fingerprint propagating in the transparent flat plate 10 (fingerprint input face plate) at a critical angle to air or more is the transparent flat plate. 10 propagates through the optical matching material layer without being totally reflected at the interface between the optical matching material layer 10 and the optical matching material layer, and then the transparent substrate 1 is not totally reflected at the interface between the optical matching material layer and the transparent substrate 1. It is a condition that satisfies the condition of propagating inside. An elastic film is coated on the transparent flat plate 10 if necessary. The role of this elastic film is similar to the conventional one. Reference numeral 23 is an illumination light source, and 29 is a fixing jig for fixing the transparent flat plate 10 and the light guide plate 12 so as not to shift.

In the fingerprint image input device thus constructed, the transparent plate 10 can be easily removed by removing the fixing jig 32.
Can be exchanged freely. Therefore, the fingerprint collation device can be used as quickly as possible.

In FIG. 3, the transparent flat plate 10 corresponds to the fingerprint image input face plate 2 of FIG. 1, and the light guide plate 11 corresponds to the transparent substrate 1 of FIG. The matching liquid 30 corresponds to the optical matching material layer 3 in FIG.

FIG. 4 shows an embodiment of the invention according to claims 1 and 3. In this embodiment, the liquid matching material 30 of the embodiment shown in FIG. 2 is replaced with a curable liquid matching material 32. After the liquid matching material 32 is filled in the sealed space formed by sealing the space between the transparent flat plate 10 and the light guide plate 12 with the sealing material 28, the filled liquid matching material 32 is cured. The cured liquid matching material 32 has a refractive index substantially the same as that of glass, and provides adhesion between the transparent flat plate 10 and the light guide plate 12, but does not have adhesiveness. Is to have. Reference numeral 31 is a fixing jig for fixing the transparent flat plate 10 and the sealing material 28. The reference numerals that are the same as those in FIG. 3 indicate the same components as those in FIG.

Therefore, also in the apparatus according to this embodiment, even if the transparent flat plate 10 or the elastic film 26 is scratched, the transparent flat plate 10 can be easily replaced, so that the fingerprint collation device can be easily replaced. It can be used as quickly as possible.

In FIG. 4, the transparent flat plate 10 corresponds to the fingerprint image input face plate 2 of FIG. 1, and the light guide plate 11 corresponds to the transparent substrate 1 of FIG. The liquid matching material 32 corresponds to the optical matching material layer 4 of FIG.

FIG. 5 shows one embodiment of the invention according to claim 4. In this embodiment, in place of the liquid matching material 30 or 32 shown in FIGS. 2 and 3, either the transparent flat plate 10 or the light guide plate 11 is coated with the matching material 34, and the coating surface is formed as the transparent flat plate 10. The light guide plate 11 and the light guide plate 11 are closely joined and fixed by a fixing jig (not shown). The matching material 34 in this case also has a refractive index that is substantially the same as that of glass, and has the property of providing adhesiveness between the transparent flat plate 10 and the light guide plate 12, but not having adhesiveness. It is a thing. The reference numerals that are the same as those in FIG. 3 indicate the same components as those in FIG.

Therefore, also in the apparatus according to this embodiment, even if the transparent flat plate 10 or the elastic film 26 is scratched, the transparent flat plate 10 can be easily replaced. It can be used as quickly as possible.

In FIG. 5, the transparent flat plate 10 corresponds to the fingerprint image input face plate 2 of FIG. 2, and the light guide plate 11 corresponds to the transparent substrate 1 of FIG. The matching material 34 corresponds to the optical matching material layer 5 in FIG.

FIG. 6 shows another embodiment of the invention according to claim 4. In this embodiment, the fingerprint sensor housing 36 is housed inside a fingerprint collation device housing 38, and the transparent flat plate 10 configured as shown in FIG. 5 is formed on the light guide plate 11 fixed to the fingerprint sensor housing 36. So that the transparent flat plate 10 can be fixed to the fingerprint collation device casing 38 at a position exactly located at the position, the notch portion 40 is provided in the fingerprint collation device casing 38, and the transparent flat plate housed in the notch portion 40 is provided. The fingerprint image input device is configured by fixing 10 with the fixing jig 42. The reference numerals that are the same as those in FIG. 5 indicate the same components as those in FIG.

Also in this embodiment, the same effect as that of the embodiment shown in FIG. 5 can be obtained. 6, the transparent flat plate 10 corresponds to the fingerprint image input face plate 2 of FIG.
Corresponds to the transparent substrate 1 of FIG. Matching material 34
Corresponds to the optical matching material layer 5 in FIG. The fingerprint sensor housing 36 corresponds to the housing 6 of the fingerprint image input device in FIG. The fixing jig 42 corresponds to the fixing jig 7 in FIG.

FIG. 7 shows an embodiment of the invention according to claim 5. In this embodiment, the fixing jig 42 of the embodiment shown in FIG. 5 is used.
The feature is that the fixing jig 44 configured so as to also serve as a finger guide is used. Other configurations are the same as those in FIG. Also, the operation and effect are the same except that a finger guide function is added.

In FIG. 7, the transparent flat plate 10 corresponds to the fingerprint image input face plate 2 of FIG. 2, and the light guide plate 11 corresponds to the transparent substrate 1 of FIG. The matching material 34 corresponds to the optical matching material layer 5 in FIG. The fingerprint sensor housing 36 corresponds to the housing 6 of the fingerprint image input device in FIG. Fixing jig 44
Corresponds to the fixing jig 7 in FIG.

FIG. 8 shows an embodiment of the invention according to claim 6. This embodiment is an example in which the liquid matching material 46 having elasticity is used in a state where the liquid matching material having curability of the embodiment shown in FIG. 3 is hardened. The liquid matching material is transparent silicone rubber. The function and effect of this embodiment are also the same as those of the embodiment shown in FIGS.

In FIG. 9, the transparent flat plate 10 corresponds to the fingerprint image input face plate 2 of FIG. 1, and the light guide plate 11 corresponds to the transparent substrate 1 of FIG. The matching material 46 corresponds to the optical matching material layer 3 of FIG.

FIG. 8 shows another embodiment of the invention according to claims 1 to 6. That is, in the embodiment shown in FIGS. 3 to 8, the transparent substrate is a parallel plate, but in this embodiment, an example in which the transparent substrate is a prism is shown. The same components among the components of the embodiment shown in FIGS. 3 to 8 are designated by the same reference numerals, and the description thereof will be omitted. The surface of the prism 50 is coated with an antireflection film.

By using the prism 50, the light reflected and scattered from the convex portion of the finger travels into the area surrounded by the dotted line L in the traveling direction of the light, but the light reflected and scattered by the concave portion (one point (Shown by a chain line) does not enter the area surrounded by the dotted line L in the light traveling direction.

Therefore, the lens 52 and the CCD 54 are arranged at the positions shown in the figure. Also in this embodiment, even if the transparent flat plate 10 or the elastic film 26 is scratched, the transparent flat plate 10 can be easily replaced, so that the fingerprint collation device can be used as quickly as possible. become.

In FIG. 9, the transparent flat plate 10 corresponds to the fingerprint image input face plate 2 of FIG. 1, and the prism 50 corresponds to the transparent substrate 1 of FIG. The matching material 34 is shown in FIGS.
Corresponding to the optical matching material layers 3, 4, and 5.

[0036]

As described above, according to the present invention, since the transparent substrate and the fingerprint image input face plate can be easily separated from each other, the fingerprint image input face plate can be freely attached to and detached from the transparent flat plate. The fingerprint image input face plate can be easily replaced. Therefore, the fingerprint collation device can be used as quickly as possible.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the invention according to claims 1 to 3 and claim 6;

FIG. 2 is a principle block diagram of the invention according to claim 4 and claim 5;

FIG. 3 is a diagram showing an embodiment of the invention according to claim 1 and claim 2;

FIG. 4 is a diagram showing an embodiment of the invention according to claim 1 and claim 3;

FIG. 5 is a diagram showing one embodiment of the invention according to claim 4;

FIG. 6 is a diagram showing another embodiment of the invention according to claim 4;

FIG. 7 is a diagram showing an embodiment of the invention according to claim 5;

FIG. 8 is a diagram showing an embodiment of the invention according to claims 1 to 6;

FIG. 9 is a diagram showing another embodiment of the invention according to claims 1 to 6;

FIG. 10 is a block diagram of a conventional fingerprint input image device.

[Explanation of symbols]

 1 Transparent Substrate 2 Fingerprint Image Input Face Plate 3 Optical Matching Material Layer 4 Optical Matching Material Layer 5 Optical Matching Material Layer 6 Fingerprint Image Input Device Housing 7 Fixing Fixture 10 Transparent Flat Plate 11 Light Guide Plate 30 Matching Liquid 32 Liquid Matching Material 34 matching material 36 fingerprint image sensor housing 42 fixing jig

Claims (4)

[Claims] 1. A parallel plate-shaped or prism-shaped transparent substrate (1) and a fingerprint image input face plate (2) having a fingerprint image input face.
A fingerprint image input device configured to include the transparent substrate (1) and the fingerprint image input face plate (2) between the transparent substrate (1) and the fingerprint image input face plate (2).
Matching material layer (3) that is in close optical contact with
And the optical matching material layer (3) propagates information light from a fingerprint propagating in the fingerprint input face plate (2) at a critical angle with respect to air or more to the fingerprint input face plate (2). After propagating through the optical matching material layer (3) without being totally reflected at the interface between the optical matching material layer (3) and the interface between the optical matching material layer (3) and the transparent substrate (1). A fingerprint image input device, characterized in that the fingerprint image input face plate (2) has a refractive index that satisfies a condition for propagating in the transparent substrate (1) without being attached, and the fingerprint image input face plate (2) is detachable. 2. The fingerprint image input device according to claim 1, wherein a transparent space is formed between a transparent substrate (1) and a fingerprint image input face plate (2) so as to form an optical space inside the sealed space. The optical matching liquid is filled with an optical matching liquid, and information light from a fingerprint propagating in the fingerprint input face plate (2) at a critical angle with respect to air or more is optically matched with the fingerprint input face plate (2). After propagating through the optical matching liquid layer (3) without being totally reflected at the interface of the liquid layer (3), it is not totally reflected at the interface between the optical matching liquid layer (3) and the transparent substrate (1). A fingerprint image input device having a refractive index satisfying a condition for propagating in the transparent substrate (1). 3. The fingerprint image input device according to claim 1, wherein the transparent substrate (1) and the fingerprint image input face plate (2) are provided between the transparent substrate (1) and the fingerprint image input face plate (2). An optical matching material layer (4) capable of being hardened after being optically adhered to is sandwiched between the optical matching material layer (4) and the fingerprint input face plate (2) is critical to air. After the information light from the fingerprint propagating in a corner or more propagates through the optical matching material layer (4) without being totally reflected at the interface between the fingerprint input face plate (2) and the optical matching material layer (4). Further, the fingerprint image input has a refractive index that satisfies the condition of propagating in the transparent substrate (1) without being totally reflected at the interface between the optical matching material layer (4) and the transparent substrate (1). Fingerprint image input device characterized by removable face plate (2) . 4. The fingerprint image input device according to claim 1, wherein the transparent substrate (1) and the fingerprint image input face plate (2) are in optical contact with each other, Alternatively, an optical matching material layer (5) having an optical matching material layer (5) coated on either one of the fingerprint image input face plate (2) is provided.
The information light from the fingerprint propagating in the fingerprint input face plate (2) at a critical angle to air or more is totally reflected at the interface between the fingerprint input face plate (2) and the optical matching material layer (5). Without propagating through the optical matching material layer (5),
Further, the optical matching material has a refractive index that satisfies the condition of propagating in the transparent substrate (1) without being totally reflected at the interface between the optical matching material layer (5) and the transparent substrate (1). A transparent substrate (1) having a layer (5) and a fingerprint image input face plate (2), and fixing for fixing the transparent substrate (1) and the fingerprint image input face plate (2) to a housing (6) of the fingerprint image input device. A fingerprint image input device comprising a jig (7) and the fingerprint image input face plate (2) being detachable.