JP2001029331A - Pattern detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform miniaturization and to pick up the images of patterns enlarged and reduced in two different directions. SOLUTION: This pattern detector 10 is provided with a prism 12 provided with a contact surface 12a for bringing a finger or the like into contact and an emitting surface, a fiber optical component 14 composed by arraying plurality of optical fibers and provided with an incident surface and the emitting surface 14c, a CCD 16 and a light source part 18 for making parallel light be incident on the contact surface 12a of the prism 12 from the inner side of the prism 12. The light source part 18, is constituted of an LED 20 and a convex lens 22 and makes the parallel light be incident on the contact surface 12a so as to make the parallel light made incident on the non-contact part of the surface of the finger or the like within the contact surface 12a of the prism 12 satisfy a total reflection condition on the contact surface 12a and to make reflected light by the contact surface 12a of the parallel light advance toward the emitting surface of the prism 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern detecting device for detecting an uneven pattern existing on the surface of an object to be measured, such as a fingerprint.

[0002]

2. Description of the Related Art A pattern detecting device for detecting an uneven pattern existing on the surface of an object to be measured is widely used, such as a fingerprint detecting device for detecting a human fingerprint pattern and a nose print detecting device for detecting a cow nose print. Used in As such a pattern detection device, for example, a fingerprint input device disclosed in Japanese Patent Application Laid-Open No. 7-334649 is known. This fingerprint input device has a triangular prism having a contact surface for contacting a finger to be measured, a light source for irradiating the contact surface with light, and a light reflected from the contact surface of light emitted from the light source. And a camera for imaging. here,
Light incident on a portion of the contact surface where the convex portion of the fingerprint is in contact enters the finger from the convex portion and is absorbed by the finger. on the other hand,
Light that has entered the part of the contact surface where the convex part of the fingerprint is not in contact (the part corresponding to the concave part of the fingerprint) is totally reflected and enters the camera. Therefore, it is possible to detect the concave and convex pattern of the fingerprint by imaging the pattern of the light reflected by the contact surface with the camera.

[0003]

However, the pattern detecting apparatus according to the prior art has the following problems. That is, in the pattern detection device according to the above-described related art, a camera is used to capture an image of a concave and convex pattern of a fingerprint, and the device itself becomes extremely large. On the other hand, even if an image pickup device such as a CCD is used instead of a camera, it is necessary to condense the pattern of light reflected by the prism with a lens or the like, and providing such a lens or the like increases the size of the device. Further, since a triangular prism is used, the fingerprint pattern imaged by the camera is a distorted fingerprint pattern reduced only in one specific direction.

Therefore, the present invention solves the above-mentioned problems, and can be constructed in a small size, and can be enlarged and reduced in two different directions.
It is an object to provide a pattern detection device capable of imaging a reduced pattern.

[0005]

In order to solve the above-mentioned problems, a pattern detecting device is a pattern detecting device for detecting a concavo-convex pattern present on a surface of an object to be measured. A prism having a contact surface that makes contact with the surface and an emission surface facing the contact surface at a predetermined angle, and an incidence surface formed by arranging a plurality of optical fibers and formed at a predetermined angle with respect to the optical axis, An optical component having an emission surface, an image sensor, and a light source that makes parallel light incident on the contact surface from inside the prism, the emission surface of the prism and the incident surface of the optical component,
The light emitting surface of the optical component is in contact with the light receiving surface of the image sensor, and the light source is configured such that the parallel light incident on a non-contact portion of the surface of the object to be measured among the contact surfaces is the contact surface. In the above, the total reflection condition is satisfied, and the parallel light is incident on the contact surface so that the reflected light of the parallel light by the contact surface proceeds toward the emission surface of the prism. I have.

By reducing or enlarging the pattern of light reflected by the contact surface by using two components, a prism and an optical component, the angle between the contact surface and the output surface of the prism can be reduced.
By changing the angle formed by the optical axis of the optical component with the entrance surface and the exit surface, it is possible to appropriately design the reduction ratio and the enlargement ratio in two different directions. A pattern of reflected light can be obtained. Further, by providing the image pickup device in contact with the emission surface of the optical component, it is not necessary to arrange a lens or the like between the optical component and the image pickup device, and the device can be downsized.

Further, in the pattern detection device of the present invention, both the first plane perpendicular to both the contact surface and the emission surface of the prism, and both the incident surface and the emission surface of the optical component are provided. The second plane perpendicular to the plane may be perpendicular to each other.

By making a first plane perpendicular to both the contact surface and the exit surface of the prism and a second plane perpendicular to both the entrance surface and the exit surface of the optical component perpendicular to each other, In the above, the pattern of the reflected light can be reduced or enlarged in one specific direction, and the pattern of the reflected light can be reduced or enlarged in the optical component in a direction perpendicular to the one direction.

In the pattern detecting device of the present invention, the angle α between the contact surface of the prism and the traveling direction of the reflected light is defined by the angle α between the exit surface of the prism and the traveling direction of the reflected light. The angle γ between the incident surface of the optical component and the optical axis may be smaller than the angle δ between the exit surface of the optical component and the optical axis.

By making α smaller than β and making γ smaller than δ, the pattern of the reflected light in the prism is reduced in one specific direction, and the pattern of the reflected light in the optical component is reduced to the specific one. It is possible to reduce in the direction perpendicular to the direction.

In the pattern detecting apparatus of the present invention, the above α and the above γ are equal to each other, and the above β and the above δ
May be equal to each other.

By making α and γ equal and β and δ equal, it is possible to make the reduction rate in the above-mentioned specific one direction and the reduction rate in the direction perpendicular to this one direction uniform.

Further, in the pattern detection device of the present invention, the above β and the above δ may be each a right angle.

By making β and δ right angles, efficient reduction is possible.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A pattern detecting device according to an embodiment of the present invention will be described with reference to the drawings. First, the configuration of the pattern detection device according to the present embodiment will be described. FIG. 1 is a perspective view of a pattern detection device according to the present embodiment, FIG. 2 is a schematic cross-sectional view taken along line II of FIG. 1, and FIG. 3 is a schematic cross-sectional view taken along line II-II of FIG. . Note that, in FIG. 3, for convenience, a fiber optical component and a CCD (details will be described later) are omitted.

The pattern detecting apparatus 10 according to the present embodiment
Is a prism 1 having a trapezoidal column shape as shown in FIG.
2, a fiber optic component 14 (optical component) having the same trapezoidal column shape and connected to the prism 12, a CCD 16 (image pickup device) connected to the fiber optic component 14, and parallel light incident on the prism 12. A light source unit 18 (light source) is provided. The light source unit 18 includes an LED 20 that emits illumination light and a convex lens 22 that collimates the illumination light emitted from the LED 20. Less than,
Each component will be described in detail.

The prism 12 is a prism made of plastic or glass, and is an object to be measured (for example, a finger).
Contact surface 12a for contacting the surfaces of
The light-exiting surface 12b opposes at an angle of 9 ° (= 90 ° -31 °).

As shown in FIG. 2, the fiber optical component 14 has a plurality of optical fibers 14a arranged in parallel and integrally formed, and each of the optical fibers 14a has an optical axis (the axis of the optical fiber 14) of three.
1 °, an incident surface 14b formed at an angle of 90 °,
And an emission surface 14c.

The exit surface 12b of the prism 12 and the entrance surface 14b of the fiber optic component 14 are bonded (contacted) with a transparent adhesive. Here, in particular, the prism 12 and the fiber optical component 14 are formed by a first plane (xz plane in FIG. 1) perpendicular to both the contact surface 12a and the emission surface 12b of the prism 12, and an incident surface of the fiber optical component 14. A second plane (xy plane in FIG. 1) perpendicular to both the 14b and the emission surface 14c is arranged to be perpendicular to each other.

The CCD 16 is provided such that the light receiving surface thereof is in contact with the emission surface 14c of the fiber optical component 14. More specifically, the light receiving surface 16a of the CCD 16 and the emission surface 14c of the fiber optic component 14 are bonded by a transparent adhesive.

The LED 20 and the convex lens 22 constituting the light source section 18 are arranged in a positional relationship as shown in FIG. That is, the LED 20
And the convex lens 22 are arranged such that the parallel light emitted from the LED 20 and collimated by the convex lens 22 is reflected from one of the surfaces of the prism 12 other than the contact surface 12a and the emission surface 12b (hereinafter, referred to as a side surface 12c). And is arranged so as to enter the contact surface 12a from the inside of the prism 12. More specifically, the contact surface 12a
Of the parallel light incident on the non-contact portion of the surface of the object to be measured satisfies the condition of total reflection on the contact surface 12a, and the reflected light of the parallel light from the contact surface 12a is directed toward the emission surface 12b of the prism 12. LED to make progress
20 and a convex lens 22 are arranged. As a result, the parallel light reflected by the contact surface 12a travels in the negative x-axis direction in FIGS.
The angle between a and the traveling direction of the reflected light is 31 °, and the angle between the exit surface 12b of the prism 12 and the traveling direction of the reflected light is 90 °.

Next, the operation and effect of the pattern detecting device according to the present embodiment will be described. FIG. 4 is a diagram showing the progress of light when the surface of the finger 100 to be measured is brought into contact with the contact surface 12a of the prism 12 and the parallel light is incident on the contact surface 12a.

Light incident on a portion of the contact surface 12 where the convex portion of the fingerprint is not in contact (a portion corresponding to the concave portion of the fingerprint) satisfies the condition of total reflection at the contact surface 12a. The light is reflected and travels in the direction of the emission surface 12b (A in FIG. 4). On the other hand, light incident on the portion of the contact surface 12 where the convex portion of the fingerprint is in contact does not satisfy the total reflection condition because the refractive index of the finger 100 is larger than air.
The light enters the finger 100 from the projection and is absorbed by the finger 100 (B in FIG. 4). Therefore, the exit surface 12 of the prism 12
From b, an optical pattern corresponding to the uneven pattern of the fingerprint on the surface of the finger 100 is output.

The angle between the contact surface 12a of the prism 12 and the traveling direction of the light reflected by the contact surface 12a is 31 °,
Since the angle between the exit surface 12b of the prism 12 and the traveling direction of the reflected light is 90 °, the prism 12
The light pattern output from the exit surface 12b of the contact surface 1b
2a in a specific direction (a-axis direction in FIG. 1) by 0.52 (= sin31 ° / sin9).
(0 °).

The light emitted from the emission surface 12b of the prism 12 is incident on the incidence surface 14b of the fiber optical component 14. The light incident on the incident surface 14b of the fiber optic component 14 is
a, and is emitted from the emission surface 14c. Therefore,
From the exit surface 14c of the fiber optical component 14, a finger 100
The light pattern corresponding to the uneven pattern of the fingerprint on the surface of is output.

The incident surface 14 of the fiber optical component 14
b and the output surface 14c have angles of 31 ° and 90 ° with the optical axis, respectively, and a first plane perpendicular to both the contact surface 12a and the output surface 12b of the prism 12 (the xz plane in FIG. 1). ) And a second plane (xy plane in FIG. 1) perpendicular to both the entrance surface 14b and the exit surface 14c of the fiber optical component 14.
Are perpendicular to each other, the light pattern incident on the incident surface 14b of the fiber optical member 14 is perpendicular to the specific direction (a-axis direction in FIG. 1) (b-axis direction in FIG. 1). Is reduced by a factor of 0.52 (= sin 31 ° / sin 90 °) and output from the exit surface 14c.

Therefore, the uneven pattern of the fingerprint formed on the contact surface 12a is reduced by a factor of 0.52 in both the vertical and horizontal directions (a-axis direction and b-axis direction in FIG. 1). An image is taken by the CCD 16.

As described above, in the pattern detection apparatus 10 according to the present embodiment, the pattern of light reflected by the contact surface 12a formed according to the uneven pattern on the surface of the object to be measured is referred to as the prism 12 and the fiber optical component 14. The reduction by the two parts allows the prism contact surface 12
By appropriately changing the angle between the a and the output surface 12b and the angle between the optical axis of the fiber optical component 14 and the input surface 14b and the output surface 14c, the reduction ratio and the enlargement ratio in two different directions are appropriately designed. Is possible. In particular, the prism 12
A first plane (xz plane in FIG. 1) perpendicular to both the contact surface 12a and the exit surface 12b, and a second plane (xz plane) perpendicular to both the entrance surface 14b and the exit surface 14c of the fiber optic component 14. (Xy plane in FIG. 1) are arranged so as to be perpendicular to each other.
2 and the fiber optics 14
Direction can be reduced.

In the pattern detecting device 10 of the present invention, the angle between the contact surface 12a of the prism 12 and the traveling direction of the reflected light and the incident surface 1 of the fiber optical component 14 are determined.
4b and the optical axis are both set to 31 °, the angle between the exit surface 12b of the prism 12 and the traveling direction of the reflected light, and the angle between the exit surface 14c of the fiber optical component 14 and the optical axis. Are both 90 °, a pattern obtained by efficiently and similarly reducing the pattern of the above-mentioned reflected light is obtained by the CCD 1.
6 enables imaging.

In the pattern detecting apparatus 10 according to the present embodiment, the CCD 16 is provided in contact with the emission surface 14c of the fiber optical component 14, so that a lens or the like can be arranged between the fiber optical component 14 and the CCD 16. This is unnecessary, and the size of the device can be reduced.

Further, the pattern detecting device 10 according to the present embodiment is configured such that, of the two optical components for reducing the pattern of the reflected light, the optical component for bringing the object to be measured into contact is constituted by a prism. Such an optical component can be manufactured at a much lower cost than when it is configured by a fiber optical component or the like. The optical component on the side in contact with the CCD 16 needs to guide the light emitted from the emission surface 12b of the prism 12 to the CCD 16, so that it is difficult to configure the optical component with the prism.

In the pattern detection device 10 according to the above embodiment, the parallel light formed by the LED 20 and the convex lens 22 is directly incident on the side surface 12c of the prism 12, so that the contact surface 12a However, various deformations can be considered. For example, as shown in FIG.
The parallel light may be incident on the side surface 12c of the prism 12 through 0. The prism 30 has an exit surface 30a in contact with the side surface 12c of the prism 12, and an entrance surface 30b having a certain angle with the exit surface 30a. here,
The refractive index of the prism 30 is equal to the refractive index of the prism 12, and the parallel light is incident perpendicularly to the incident surface 30 b of the prism 30. Therefore, the parallel light formed by the LED 20 and the convex lens 22 does not change the traveling direction and does not change the traveling direction.
Incident on. With such a configuration, the light source unit 18
When the prisms 12 and 30 are integrated, the light source 18
The optical axis of the parallel light emitted from the
Since the adjustment may be performed so as to be perpendicular to 0b, the adjustment is facilitated.

In the modification shown in FIG. 5, parallel light is transmitted through the prism 30 to the side surface 12 of the prism 12.
c, but as shown in FIG.
Instead of 0, a fiber optical component 32 formed by integrally forming a plurality of optical fibers in parallel may be used. The fiber optical component 32 has an exit surface 32a in contact with the side surface 12c of the prism 12, and an entrance surface 32b having a certain angle with the exit surface 32a. Here, the optical axis of the optical fiber constituting the fiber optical component 32 is
The refractive index of the core of the optical fiber constituting the fiber optical component 32 is equal to the refractive index of the prism 12. The numerical aperture of the optical fiber constituting the fiber optical component 32 is extremely small (almost zero). Here, since the parallel light is incident perpendicularly to the incident surface 30b of the fiber optical component, the parallel light formed by the LED 20 and the convex lens 22 does not change the traveling direction and is Contact surface 1
2a. By using the fiber optical component 32, the divergence angle of parallel light incident on the side surface 12c of the prism 12 can be reduced, and high-quality parallel light can be incident on the contact surface 12a of the prism 12. As a result, a clear output pattern can be obtained.

As a similar modification, a capillary plate 34 as shown in FIG. 7 may be used instead of the prism 30 shown in FIG. The capillary plate 34
A member having a large number of through holes formed in parallel with each other, and a metal film that reflects light is formed on an inner wall of the through hole. The capillary plate 34 has an exit surface 34a in contact with the side surface 12c of the prism 12, and an entrance surface 34b having a certain angle with the exit surface 34a, and the through-hole is perpendicular to the entrance surface 34b. It is formed so that it becomes. The parallel light is applied to the capillary plate 34.
After being perpendicularly incident on the incident surface 34b, the exit surface 34a of the capillary plate 34 and the side surface 12 of the prism 12
The light is refracted at the interface with c and enters the contact surface 12a of the prism 12. Also by using the capillary plate 34, the spread angle of the parallel light incident on the side surface 12c of the prism 12 can be reduced, and high-quality parallel light can be incident on the contact surface 12a of the prism 12. As a result, a clear output pattern can be obtained.

In place of the prism 30 shown in FIG. 5, a prism 36 as shown in FIG. 8 may be used. The prism 36 is formed with an exit surface 36a in contact with the side surface 12c of the prism 12, an incident surface 36b formed perpendicular to the exit surface 36a, and a certain angle with respect to the exit surface 36a and the entrance surface 36b. The prism 36 has a reflective surface 36c, and the refractive index of the prism 36 is equal to the refractive index of the prism 12. Further, a reflection mirror 37 is adhered to the reflection surface 36c, so that light incident on the reflection surface 36c can be reflected. Here, the parallel light is perpendicularly incident on the incident surface 36b of the prism 36, and is reflected by the reflecting surface 36c.
The light enters the side surface 12c of the prism 12 from the emission surface 36a of the prism 12, and enters the contact surface 12a of the prism 12. With such a configuration, the LED 20 constituting the light source unit 18 can be used.
And the convex lens 22 can be arranged in the vicinity of the prism 12, and the size of the apparatus can be further reduced. In this case, as shown in FIG. 9, the convex lens 22 is a plano-convex lens, and the convex lens 22 is an incident surface 36 of the prism 36.
It may be provided in contact with b. The convex lens 22 is connected to the prism 36
The device can be further reduced in size by being provided in contact with the incident surface 36b.

Further, in the pattern detection device 10 according to the above embodiment, the angle between the exit surface 12b of the prism 12 and the traveling direction of the reflected light is 90 °. Like the detection device 50,
The angle may be acute. For example, the contact surface 1 of the prism 12
The angle formed between 2a and the traveling direction of the reflected light is 15 °, the angle formed between the emission surface 12b and the traveling direction of the reflected light is 30 °,
Assuming that the angle between the incident surface 14b of the fiber optical component 14 and the optical axis is 7.5 ° and the angle between the output surface 14c and the optical axis is 90 °, the concavo-convex pattern of the fingerprint contacting the contact surface 12a of the prism 12 , In the a-axis direction by the prism 12.
26 (= sin15 ° / sin90 °) times,
It is magnified by 2 (= sin 90 ° / sin 30 °) times in the b-axis direction and output from the exit surface 12b. The light pattern output from the exit surface 12b of the prism 12 is 0.13 (= s) in the b-axis direction by the fiber optical member 14.
(in 7.5 / sin 90 °) times and the emission surface 14
c and is imaged by the CCD 16. Therefore, the concavo-convex pattern of the fingerprint formed on the contact surface 12a is
The similar and reduced light pattern is reduced by a factor of 0.26 in both the vertical and horizontal directions (a-axis direction and b-axis direction).
16 is imaged.

Further, as a modified example of the pattern detection device 10 according to the above embodiment, a pattern detection device 60 as shown in FIGS. 11 and 12 can be considered. Here, FIG. 11 is a perspective view of the pattern detection device 60, and FIG.
FIG. 2 is a schematic sectional view taken along line II of FIG. In FIG. 12, for convenience, the fiber optical component 14 and the CCD 16
Is omitted.

Here, the pattern detecting apparatus described with reference to FIG. 5 combines the prism 12 and the prism 30 and transmits the parallel light incident perpendicular to the incident surface 30b of the prism 30 to the contact surface 12a of the prism 12. However, the pattern detection device 60 according to the present modification includes a prism 62 in which the prism 12 and the prism 30 are integrated.

That is, the pattern detecting device 60 is configured as shown in FIG.
As shown in FIG. 1, a prism 62 having a trapezoidal columnar shape, a fiber optical component 14 connected to the prism 62, a CCD 16 connected to the fiber optical component 14, and a light source unit 18 for inputting parallel light to the prism 62 are provided. It is composed.

The prism 62 is a prism made of plastic or glass, and has a contact surface 62a for making contact with the surface of the object to be measured, and a contact surface 62a with a contact angle of 59 °.
The incident surface 62b and the outgoing surface 62c which are non-parallel to each other at an angle, and the opposing surface 62d which is parallel to the contact surface 62a. That is, the contact surface 62a, the incident surface 62b, the emission surface 62c, and the opposing surface 62d constitute four trapezoidal columns. Here, the exit surface 62c of the prism 62 and the entrance surface 14b of the fiber optical component 14 are bonded by a transparent adhesive.

The LED 20 and the convex lens 22 constituting the light source section 18 are arranged in a positional relationship as shown in FIG. That is, the light source unit 1
8 is incident on the incident surface 62b of the prism 62.
Are arranged so as to be perpendicularly incident on the.

With this configuration, the parallel light is incident on the contact surface 62a of the prism 62 at an angle of 31 °, and the reflected light is
The light travels at an angle of 90 ° with respect to the light exit surface 62c.

The pattern detecting device 60 according to this modification example
Can reduce the number of components as compared with the pattern detection device described with reference to FIG. That is, in the pattern detection device described with reference to FIG. 5, the portion configured using the two components, the prism 12 and the prism 30, can be configured using the prism 62 that is a single component. Further, the pattern detection device described with reference to FIG.
Since the bonding was performed, a bonding process was required for its manufacture. However, the bonding step is unnecessary in the pattern detection device 60 according to the present modification. Accordingly, polishing of the bonding surface is not required, and the contact surface 12a, the emission surface 12b, the side surface 12c of the prism 12, and the emission surface 30 of the prism 30 are provided in the pattern detection device described with reference to FIG.
a, it was necessary to polish a total of five surfaces of the incident surface 30b. However, in the pattern detection device 60 according to the present modification, a total of three surfaces of the contact surface 62a, the incident surface 62b, and the output surface 62c of the prism 62 were polished. Just do it. In particular,
When the prism 62 is cut out from a sheet glass or the like,
If polishing of the contact surface 62a is unnecessary, the incident surface 62b
It is only necessary to polish the two surfaces, ie, the light exit surface 62c. Furthermore, since the prism 62 has a simple shape, it can be easily cut out from a glass sheet. as a result,
The yield is high and the manufacturing cost is low.

In the pattern detectors 10, 50 and 60 according to the above embodiment, the light source 18 is
0 and the convex lens 22, but the convex lens 2
A Fresnel lens may be used instead of 2. By using the Fresnel lens, the size of the apparatus can be further reduced.

The pattern detectors 10, 50, and 60 according to the above-described embodiments are configured to reduce the size of the uneven pattern on the surface of the object to be measured and capture the image. By appropriately designing the angle formed by the optical axis of the fiber optical component 14, the angle formed by the incident surface 14b, and the outgoing surface 14c, etc., it is possible to magnify and photograph the uneven pattern on the surface of the measured object. It is also possible.

[0046]

According to the pattern detecting apparatus of the present invention, the angle formed between the contact surface of the prism and the exit surface is reduced by reducing or enlarging the pattern of the light reflected by the contact surface by the two components of the prism and the optical component. By changing the angle formed by the optical axis of the component with the incident surface and the outgoing surface, it is possible to appropriately design the reduction ratio and the enlargement ratio in two different directions. It becomes possible to obtain a light pattern. Further, by providing the image pickup device in contact with the emission surface of the optical component, it is not necessary to arrange a lens or the like between the optical component and the image pickup device, and the device can be downsized.

Further, in the pattern detection device of the present invention, the first plane perpendicular to both the contact surface and the exit surface of the prism, and the second plane perpendicular to both the entrance surface and the exit surface of the optical component. By making the planes perpendicular to each other, the pattern of the reflected light is reduced or enlarged in one specific direction in the prism, and the pattern of the reflected light is reduced or enlarged in the direction perpendicular to the specific direction in the optical component. It is possible to do.

In the pattern detection device of the present invention, the angle α between the contact surface of the prism and the traveling direction of the reflected light is defined as the angle between the emission surface of the prism and the traveling direction of the reflected light. β, and the angle γ between the incident surface of the optical component and the optical axis is made smaller than the angle δ between the output surface of the optical component and the optical axis. The light pattern can be reduced in one specific direction, and the reflected light pattern in the optical component can be reduced in a direction perpendicular to the specific one direction.

Further, in the pattern detection apparatus of the present invention, by making α and γ equal, and β and δ equal, the reduction ratio in the specific one direction and the reduction ratio in the direction perpendicular thereto are made uniform. Becomes possible.

In the pattern detection device of the present invention, by making β and δ right angles, efficient reduction is possible.

[Brief description of the drawings]

FIG. 1 is a perspective view of a pattern detection device.

FIG. 2 is a schematic cross-sectional view taken along line II of FIG.

FIG. 3 is a schematic sectional view taken along the line II-II in FIG.

FIG. 4 is a diagram showing a state of light traveling.

FIG. 5 is a diagram showing a modification of the pattern detection device.

FIG. 6 is a diagram showing a modification of the pattern detection device.

FIG. 7 is a diagram showing a modification of the pattern detection device.

FIG. 8 is a diagram showing a modification of the pattern detection device.

FIG. 9 is a diagram showing a modification of the pattern detection device.

FIG. 10 is a diagram showing a modification of the pattern detection device.

FIG. 11 is a diagram showing a modification of the pattern detection device.

FIG. 12 is a schematic sectional view taken along the line II of FIG. 11;

[Explanation of symbols]

10, 50, 60 ... pattern detection device, 12, 30, 3
6,62 ... Prism, 14,32 ... Fiber optical parts,
16: CCD, 18: light source unit, 20: LED, 22: convex lens, 34: capillary plate, 37: reflection mirror, 100: finger

Claims (5)

[Claims] 1. A pattern detecting apparatus for detecting an uneven pattern present on a surface of an object to be measured, comprising: a contact surface for contacting the surface of the object to be measured; and an emission surface facing the contact surface at a predetermined angle. A prism having a plurality of optical fibers arranged therein, an optical component having an entrance surface and an exit surface each formed at a predetermined angle with respect to the optical axis, an image pickup device, and the contact surface A light source that allows parallel light to enter from the inside of the prism, wherein the emission surface of the prism, the incidence surface of the optical component, the emission surface of the optical component, and the light receiving surface of the imaging element are in contact with each other. The light source may be configured such that the parallel light incident on a non-contact portion of the surface of the measurement target in the contact surface satisfies a condition of total reflection on the contact surface, and the parallel light is reflected by the contact surface of the parallel light. As the reflected light travels toward the exit surface of the prism,
A pattern detecting device, wherein the parallel light is incident on the contact surface. 2. A first plane perpendicular to both the contact surface and the exit surface of the prism, and a second plane perpendicular to both the entrance surface and the exit surface of the optical component. Are perpendicular to each other. The pattern detecting device according to claim 1, wherein 3. An angle α between the contact surface of the prism and the traveling direction of the reflected light is smaller than an angle β between the emission surface of the prism and the traveling direction of the reflected light. The angle γ between the incident surface and the optical axis is
3. The pattern detecting device according to claim 2, wherein an angle δ between the light exit surface of the optical component and the optical axis is smaller than the angle δ. 4. The pattern detection apparatus according to claim 3, wherein the α and the γ are equal to each other, and the β and the δ are equal to each other. 5. The pattern detection device according to claim 4, wherein the β and the δ are each a right angle.