JPS63221485A - Ruggedness information detector - Google Patents

Abstract

PURPOSE:To obtain image information in accordance with an equal clear ruggedness by scanning the rugged surfaces pressured to the contacting part of a transparent flat plate with a linear laser light through a cylindrical lens. CONSTITUTION:A laser light from a semiconductor laser 13 of a light source part 15 comes to be a bright linear laser light 23 by a cylindrical lens and a hand and finger 7 of the rugged surfaces pressured to a rugged surface contacting part 20 of a transparent flat plate 19 is illuminated. By the moving of the light source part 15, the hand and finger 7 is scanned with the laser light 23. A reflecting light 24 to execute the total reflection at the boundary of the rugged surfaces of the fingerprint of the hand and finger is made incident on an image pick-up element 16 outside the flat plate 19 while the light is emitted from the flat plate 19 with a hologram 21. With the illumination light which is bright due to the scanning of the linear laser light and does not have unevenness in a scanning direction, the image information in accordance with the equal and clear rugged information is obtained.

Description

[Detailed Description of the Invention] [Summary] In an unevenness information detection device that detects fingerprints, etc. of a finger pressed against an uneven surface contact portion of a transparent flat plate, the emitted light of a semiconductor laser is narrowed into a line by a cylindrical lens, and the line is Clear imaging is achieved by scanning the contact area with shaped illumination light.

[Industrial application field]

The present invention relates to an unevenness information detector, and particularly to a fingerprint detection device for detecting fingerprints.

As the information society progresses, stakeholders are becoming increasingly concerned about how to maintain the airtightness of information processing systems, for example, how to ensure system security as computers are introduced into a wide range of social systems. ing.

Therefore, as a means of verifying the identity of a person when entering a computer room or using a terminal, a fingerprint detection device that directly optically detects fingerprints, which differ from person to person and is safe from loss or theft, has been developed. Appeared.

[Conventional technology]

FIG. 2 is a schematic side view showing the main parts of a conventional fingerprint detection device (unevenness information detection device).

In FIG. 2, the fingerprint detection device 1 includes a semiconductor laser 3 and an imaging camera (imaging device) 4 provided below the fingerprint sensor 2. The fingerprint sensor 2 includes a transparent flat plate 5 made of optical glass.
A hologram 6 is provided on the lower surface of the hologram 6, and an imaging camera 4 is disposed so as to face the hologram 6.

In such a device 1, a finger 7 is pressed against a finger contact portion of the fingerprint sensor 2, and the contact portion between the transparent flat plate 5 and the finger 7 is illuminated with illumination light 8 emitted from the semiconductor laser 3 from within the transparent flat plate 5. .

Then, the illumination light 8 irradiated onto the part of the finger 7 opposite to the concave part 7b formed by the fingerprint is transmitted above the transparent flat plate 5, and all of the light scattered by the concave part 7b escapes into the air layer below, while the convex part 7a of the fingerprint The illumination light 8 irradiated onto the contact area is scattered at the contact interface, and only the light scattered above the critical angle is guided to the detection hologram 6 and emitted downward.

As a result, the imaging camera 4 captures a fingerprint image in which the convex portions 7a are bright and the concave portions 7b are dark.

[Problem that the invention seeks to solve]

However, the illumination light of a semiconductor laser has a far-field pattern in which the light intensity decreases in the radial direction from the optical axis.
A conventional unevenness information detection device has a structure in which light emitted from a semiconductor laser is incident on a transparent flat plate in a far-field pattern to illuminate the contact area of the finger.

Therefore, there is a problem in that the periphery of the photographed image is darker than the center, making it impossible to detect a uniform pattern.

[Means for solving problems]

According to FIG. 1, the unevenness information detection device of the present invention aimed at eliminating the above-mentioned problems includes a transparent flat plate 19 provided with an uneven surface contact portion 20 that presses the uneven surface for detection, and a transparent flat plate 19 that emits a laser beam. A semiconductor laser 13 , a cylindrical lens 4 that focuses the emitted light of the semiconductor laser 13 into a linear shape and projects the linear illumination light onto a transparent flat plate 19 , and a scanning device that scans the illumination light from inside the transparent flat plate 19 to the contact portion 20 . and an image pickup device 16 for photographing the reflected light of the illumination light illuminated on the contact portion 20 from inside the transparent flat plate 19 outside the transparent flat plate 19.

[Effect]

According to the above means, by narrowing the emitted light of the semiconductor laser, which has two-dimensional illumination unevenness, into a linear shape using a cylindrical lens, the illumination unevenness is made into one-dimensional illumination light, and the illuminance is increased, and the linear illumination light is scans the uneven surface contact portion and images the uneven surface pattern for detection that is in close contact with the contact portion. As a result, it is now possible to obtain brighter images with less difference between brightness and darkness than before.

〔Example〕

EMBODIMENT OF THE INVENTION Below, the uneven|corrugated information detection apparatus (fingerprint detection apparatus) by the Example of this invention is demonstrated using drawing.

FIG. 1 is a perspective view schematically showing the main parts of a fingerprint detection device according to an embodiment of the present invention.

In FIG. 1, the fingerprint detection device 11 includes a semiconductor laser 13 and a cylindrical lens 14 below the fingerprint sensor 12.
It has a light source section 15 that is movable in the left-right direction and an imaging section 18 that has a plurality of image pickup elements 16 mounted on a movable table 17 and is movable in the left-right direction.

The transparent flat plate 19 of the fingerprint sensor 12 has a finger (uneven surface) contact portion 20 near the left end of the upper surface, and a hologram 21 for extracting reflected light within the transparent flat plate 19 near the right end of the lower surface.

In such a fingerprint detection device 11, in the light source section 15 facing below the contact section 20, the cylindrical lens 14 focuses the emitted light 22 of the semiconductor laser 13 into a linear shape in the front and rear direction, and the linear illumination light 23 is , the contact section 20 is illuminated from right to left (or from left to right) by moving the light source section 15.

On the other hand, the imaging unit 18 facing below the hologram 21 is
A plurality of image sensors 16 are aligned in the front and back direction, and the light source section 15
move from right to left (or left to right) in sync with the movement of

Therefore, the finger 7 is pressed against the contact part 20, and the linear illumination light 23
The light source section 1 scans the contact section 20 from the right end to the left end.
5 at a predetermined speed, and the imaging section 18 is moved from right to left at a speed synchronized with the moving speed of the light source section 15 according to the magnification of the imaging optical system. When the imaging unit 18 is moved at a constant speed in the same direction, a CD camera captures an image in which the convex portion (7a) of the finger 7 is bright and the concave portion (7b) is dark.

In the figure, 24 is a part of the illumination light 23 scattered at the contact interface between the convex part 7a of the finger 7 and the surface of the contact part 20, and the part 24 of the scattered light propagated within the transparent flat plate 19 is ,
A hologram 21 emits light, and the hologram 25 emits light from the image sensor 1.
6.

In addition, the reason why the imaging unit 18 is configured to move in the above embodiment is to enable imaging with a small number of imaging elements 16.If a larger number of imaging elements 16 than in the embodiment are arranged in a matrix, such movement can be achieved. means are no longer needed.

〔Effect of the invention〕

As explained above, according to the present invention, by narrowing the emitted light of the semiconductor laser into a linear shape using a cylindrical lens, uneven illumination is eliminated in the width direction (the moving direction of the linear illumination light), and the illumination light is brighter than before. This has the effect of making it possible to obtain uniform and clear image information.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing the main parts of a fingerprint detection device according to an embodiment of the present invention, and FIG. 2 is a schematic side view showing the main parts of a conventional fingerprint detection device. In the figure, 11 is a fingerprint detection device (unevenness information detection device), 13 is a semiconductor laser, 14 is a cylindrical lens, 15 is a light source section, 16 is an imaging element, 18 is an imaging section, 19 is a transparent flat plate, 20 is an uneven surface contact 22 is the emitted light, 23 is the linear illumination light, 24 is a part of the reflected light, and 25 is the emitted light. I don't like it 1□Oh. -to 1 ko71, 1'-Vsu, t'''':!, ρ(〈Yu

Claims (3)

[Claims] (1) A transparent flat plate (19) provided with a concavo-convex surface contact portion (20) that presses the concave-convex surface for detection, a semiconductor laser (13) that emits laser light, and a line that emits the light emitted from the semiconductor laser (13). The transparent flat plate (19
) that projects linear illumination light onto the cylindrical lens (1
4), scanning means for scanning the illumination light from inside the transparent flat plate (19) to the contact portion (20); and scanning means for scanning the illumination light from inside the transparent flat plate (19) to the contact portion (20); An unevenness information detection device characterized by comprising an image sensor (16) that photographs reflected light outside the transparent flat plate (19). (2) The unevenness information detecting device according to claim 1, wherein the scanning means is a moving means for moving the semiconductor laser (13) and the cylindrical lens (14) together. (3) The unevenness information detection device according to claim 2, further comprising means for moving the image pickup device (16) in conjunction with the moving means.