KR100347269B1 - Fingerprint recognition device - Google Patents

Abstract

A fingerprint recognition device is disclosed in which the overall optical size is compact and its assembly is simple. According to a first embodiment, the device comprises an internal total reflection prism shaped to bend downward from the thick top. A fingerprint region is provided on an upper portion of the prism, and a surface light emitting diode is aligned on the front incident surface to illuminate the fingerprint region. The illuminated fingerprint image is sequentially reflected by the reflective surfaces forming the outer wall of the prism. The fingerprint image emitted through the prism's exit surface is imaged in the image sensor. A lens surface such as a spherical surface, an aspherical surface, a toric surface, or the like may be formed on the reflective surface or the emission surface. According to a second embodiment, the device comprises two right angle prisms whose respective oblique sides overlap a predetermined area. Each outer wall of the rectangular prism acts as a total reflection mirror to convey the fingerprint image. Lens surfaces may also be formed on the reflective surfaces of the two rectangular prisms. According to the third embodiment, the oblique surface of one rectangular prism includes both the entrance face and the exit face, and according to the fourth embodiment, one triangular prism is provided to make the fingerprint recognition system as compact as possible.

Description

Fingerprint Reader {FINGERPRINT RECOGNITION DEVICE}

The present invention relates to a fingerprint recognition device, and more particularly, to a fingerprint recognition device that is compact and easy to assemble.

In the field of fingerprint recognition, at each ridges and valleys of fingerprints, patterns of line endings and line bifurcations are known to provide a unique set of so-called "minutia". The shape, position and angle orientation of the minutia is a unique feature for each finger. The fingerprint can be reproduced on a flat surface, i.e., the fingerprint can be scanned to recognize each minutia. Electronic techniques for such scanning are complex and expensive. Fingerprints are scanned and electronically processed to provide recognition of the shape, position and angular orientation of each minutia. In practice, such a recognition process is expensive and its adoption is extremely limited.

1 shows a fingerprint recognition device 100 according to the prior art. Referring to FIG. 1, the fingerprint recognition apparatus 100 includes a casing 102 on which a fingerprint region 110 is provided. The fingerprint to be recognized is imprinted on the fingerprint area 110. Surface light emitting diodes disposed on the first PC 120 and the first PC 120 to irradiate surface light corresponding to the width of the fingerprint area 110 toward the fingerprint area 110. 125 is installed. The surface light emitted from the surface emitting diode 125 is reflected at the bottom of the fingerprint area 110 and passes through the condensing objective lens 130 and is condensed on the mirror 140. The light focused on the mirror 140 is imaged on the image sensor 170 installed in the second PC 180 through the pinhole 150 and the sensor lens 160.

The image formed by the image sensor 170 is converted into a digital signal by the data acquisition board 190 of the desktop computer and then displayed through the monitor 198.

2A and 2B show a plan view and a cross sectional view of a fingerprint region 110 according to the prior art. 2A and 2B, a silicon surface 112 is provided on the upper portion of the fingerprint area 110 so that the fingerprint can be taken as clearly as possible. A light transmissive polycarbonate is provided to surround the bottom of the silicon face 112, and a micro prism 116 is attached to the bottom face to increase the directivity of the light.

That is, the conventional optical system for fingerprint recognition illuminates the light emitted from the surface light emitting diode 125 to the fingerprint area 110, and the illuminated fingerprint is reflected from the mirror 140 after passing through the condensing objective lens 130. The sensor lens 160 forms an image sensor, for example, a CMOS or a CCD. As described above, the formed fingerprint is separated and recognized as an image such as a point, bifurcation, line ending, enclosure, short ridge, etc. Stored. Therefore, in the case of recognizing a certain image image, the authenticity is distinguished from the personal information data.

However, the above-described conventional optical system has a long distance from the fingerprint area to the image sensor, and thus the size of the system as a whole becomes large. In addition, the use of several lenses and mirrors is complicated to assemble, and the casing is required to reflect the illuminated light and the additional structure of the entire optical system is complicated by using a micro prism to increase the directivity of the light. . That is, the number of parts increases, the cost increases, the assembly process is complicated, and the size of each part is large, making it difficult to manufacture small.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art, and to provide a fingerprint recognition device which can reduce the size of the entire optical system compactly and facilitate assembly.

1 is a schematic diagram of a fingerprint recognition device according to the prior art.

2A and 2B are plan and cross-sectional views, respectively, of a fingerprint region.

3A is a schematic diagram of a fingerprint recognition device according to a first embodiment of the present invention.

3B is a schematic diagram of a fingerprint recognition device showing a state where a lens surface is formed on a prism according to the first embodiment.

4 is a perspective view of the total internal reflection prism according to the first embodiment;

5 and 6 are plan and side views, respectively, of the surface-emitting diode.

7 and 8 are plan and side views of the image sensor, respectively.

9 is a schematic diagram of a fingerprint recognition device according to a second embodiment of the present invention.

10 is a layout view of two rectangular prisms according to the second embodiment;

11 is a cross-sectional view of a rectangular prism with an aspherical surface formed.

12 is a schematic diagram of a fingerprint recognition device employing a right angle prism according to a third preferred embodiment of the present invention.

Fig. 13 is a schematic diagram of a fingerprint recognition device employing a triangular prism according to a fourth preferred embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

200: prism 210: fingerprint area

202: surface emitting diodes 220, 230, and 240: first, second, and third reflecting surfaces

260: sensor lens 270: image sensor

201, 272: PCB

310, 320: first and second right angle prism

319, 324, 325, 326: lens surface 420: triangular prism

In order to achieve the above object of the present invention, the present invention provides a surface light emitting diode, an image sensor in which a fingerprint image is formed, and a data detection board for detecting and converting the formed fingerprint image into a digital signal. A fingerprint recognition device having an electronic control unit (ECU) for recognizing a digital signal and a digital signal, the fingerprint area having a light incident through the incident surface is provided on a predetermined surface adjacent to the incident surface. The present invention provides a fingerprint recognition device comprising an internal total reflection prism formed with an internal reflection surface reflecting a fingerprint image illuminated by the light.

According to the first embodiment of the present invention, the first, second and third reflecting surfaces of the reflective prism are bent at predetermined angles sequentially with respect to each other from the side where the fingerprint area is formed. It is the total internal reflection mirror respectively formed in a 3rd side.

The formed fingerprint image is recognized by the image sensor by being divided into dots, bifurcation, line endings, closed curves, and short lines.

According to a second embodiment of the present invention, the reflective prism includes first and second rectangular prisms in which each oblique surface overlaps a predetermined area. The first oblique surface of the first rectangular prism includes an incident surface to which light from the light emitting diode is incident and a first attachment surface partially overlapping the second oblique surface of the second rectangular prism. A fingerprint area is provided on an opposing first side, the first reflecting surface being a second side between the first inclined surface and the first side.

In this case, the second and third reflecting surfaces are respectively the third and fourth side surfaces of the second rectangular prism. Except for the second attachment surface facing the first attachment surface of the second inclined surface, light reflected by the fingerprint area, the first, second and third reflection surfaces exits the reflection prism. It is an exit surface.

Preferably, an aspherical surface that functions as a lens may be formed on the first, second reflective surface, or the exit surface. The aspherical surface has a symmetric torus, asymmetric torus, or cylinder shape.

As described above, fingerprint recognition may be performed by using total internal reflection by combining one or two ejection prisms, thereby reducing the size of the entire optical system and facilitating assembly by replacing a plurality of mirrors.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

First embodiment

3A shows a fingerprint recognition device according to a first embodiment of the present invention. The device is provided with a fingerprint area 210 on its upper surface, and inside, first, second and third reflecting surfaces 220, 230 and 240 which are total internal reflection surfaces that continuously reflect a fingerprint image illuminated by light. It includes a reflecting prism 200, including. As shown in FIG. 4, the reflective prism 200 has a shape that is curved downward from the thick upper portion. According to a first embodiment of the invention, the first, second and third reflecting surfaces 220, 230, 240 are sequentially arranged with respect to each other from the side of the reflective prism 200 in which the fingerprint region 210 is formed. An internal total reflection mirror is formed on each of the first, second and third side surfaces which are bent at a predetermined angle. Preferably, prism 200 is injection molded.

Meanwhile, the fingerprint area 210 may have a conventional structure described in the prior art.

On the incident surface 250 side of the reflective prism 200 is provided a surface light emitting diode 202 that emits light drawing a predetermined surface. Light emitted from the surface light emitting diode 202 is incident to the fingerprint area 210. The light incident by the light emitting diode 202 into the reflective prism 200 passes through total reflection by being incident on each internal total reflection surface of the light emitting diode 202 at a predetermined critical angle or more according to the refractive index. 5 and 6 illustrate a structure of a surface light emitting diode 202 according to an embodiment of the present invention. 5 and 6, the surface light emitting diode 202 is a light emitting diode having a substantially rectangular shape, and is mounted on the PCB 201 to emit light.

The fingerprint image reflected by the third reflection surface 240 passes through the exit surface 204 of the reflection prism 200 and diffuses out of the reflection prism 200. The beam diffused outward is collimated through the sensor lens 260. Thereafter, the fingerprint image collimated by the sensor lens 260 is imaged on an image sensor 270 such as a CCD.

Meanwhile, lens surfaces having a function of a lens may be formed on the first, second and third reflection surfaces 220, 230, 240, or the emission surface 204. The lens surface may be a spherical surface, an aspherical surface, or a toric surface.

The fingerprint image signal formed on the image sensor 270 is input to a data acquisition board 298 and converted into a digital signal. The fingerprint signal converted into the digital signal is converted into a point, a bifurcation, a line ending, an enclosure, and a short ridge by an electronic control unit (ECU) 299. It is recognized separately. 7 and 8 illustrate an image sensor 270 according to one embodiment of the invention. The image sensor 270 is mounted and operated on the PCB 272 as a module including the sensors on the grid.

Hereinafter, a fingerprint recognition process of the fingerprint recognition apparatus according to the first embodiment of the present invention will be described.

The light emitted from the light emitting diode 202 is emitted in the form of surface emission so as to illuminate the full width of the fingerprint region 210 formed on the reflective prism 200. The surface light emission is irradiated to the fingerprint area 210 through the entrance surface 250. In the fingerprint area 210, a predetermined fingerprint is restored as it is by the grease of a finger and is illuminated by the surface light emission. The illuminated fingerprint image is reflected on the sequential first, second and third reflecting surfaces 220, 230, and 240 forming the outer wall of the reflecting prism 200 and is outside the prism 200 through the exit surface 204. Go on. The fingerprint image leaving the prism 200 is collimated by the sensor lens 260, which is a condenser lens, and is imaged on the image sensor 270. The fingerprint image signal formed on the image sensor 270 is input to the data acquisition board 298 and converted into a digital signal. The fingerprint signal converted into the digital signal is recognized by being separated into a point, a bifurcation, a line ending, an enclosure, and a short ridge by the ECU 299. Personal fingerprint information is stored in the ECU (not shown). The information stored as described above is used to determine the authenticity of each individual.

On the other hand, when the lens surface is formed on each of the internal reflection surface and the emission surface, the sensor lens 260 can be omitted.

Second embodiment

9 shows a fingerprint recognition device according to a second embodiment of the present invention.

According to the second embodiment of the present invention, the fingerprint recognition apparatus includes first and second rectangular prisms 310 and 320 in which each oblique surface overlaps a predetermined area. The first bevel 316 of the first right prism 310 partially overlaps the incident face 312 on which light from the light emitting diode 302 is incident and the second bevel 322 of the second right prism 320. The paper is composed of a first attachment surface 314. That is, as shown in Figure 10, the reflective prism according to the second embodiment is composed of two right angle prism (310, 320) arranged up and down so that the oblique surface of each other overlap a predetermined area. Preferably, the rectangular prisms 310 and 320 are injection molded.

The light emitting diode 302 has the same structure as the light emitting diode 202 in the first embodiment.

The fingerprint region 330 is provided on the first side 318 opposite the first attaching surface 314 of the first right prism 310. The fingerprint region 210 may have a conventional structure. The second side surface 319 between the first bevel 316 and the first side surface 318 becomes a first reflective surface. The third and fourth side surfaces 324, 325 of the second rectangular prism 320 become second and third reflective surfaces. The remaining portions of the second oblique surface 327 of the second rectangular prism 320 except for the second attachment surface 322 facing the first attachment surface 314 may be the fingerprint area 330, the first, second, Light reflected by the third reflecting surfaces 319, 324, and 325 becomes an exit surface 326 that exits the reflection prism.

The sensor lens 340, which is a condenser lens, is aligned near the exit surface 326. In addition, the image sensor 350 is disposed to align with the sensor lens 340. The image sensor 350 in the second embodiment has the same structure as the image sensor 270 in the first embodiment.

The fingerprint image signal formed on the image sensor 350 is input to a data acquisition board 398 and converted into a digital signal. The fingerprint signal converted into the digital signal is converted into a point, a bifurcation, a line ending, an enclosure, and a short ridge by an electronic control unit (ECU) 399. Fractional recognition is stored.

Preferably, the first, second and third reflecting surfaces 319, 324, 325, or exit surface 326 have a spherical, aspheric or toric surface that functions as a lens, as shown in FIG. 11. toric surface may be formed. The aspherical surface may have a symmetric toric, asymmetric toric, or cylinder shape. In this case, the sensor lens 340 may be omitted in the fingerprint recognition system.

Hereinafter, the fingerprint recognition method according to the second embodiment will be described.

The surface light emitted by the surface light emitting diode 302 enters into the prism through the incident surface 312 of the first rectangular prism 310 and reaches the fingerprint region 330. The fingerprint imprinted on the fingerprint area is illuminated and reflected by the light and then reflected on the first, second, and third reflecting surfaces 319, 324, and 325, and then the exit surface of the second rectangular prism 320. Enter outside through 326.

The fingerprint image leaving the prism is collimated by the sensor lens 340, which is a condensing lens, to be imaged on the image sensor 350. The fingerprint image signal formed on the image sensor 350 is input to the data acquisition board 398 and converted into a digital signal. The fingerprint signal converted into the digital signal is classified and stored by the ECU 399 as a point, a bifurcation, a line ending, an enclosure, and a short ridge. . Therefore, the personal fingerprint information is stored in the ECU (not shown). The information stored as described above is used to determine the authenticity of each individual.

In this case, when the lens surface is formed on each of the internal reflection surface and the emission surface, the sensor lens 340 may be omitted.

Third embodiment

12 illustrates a fingerprint recognition device 500 according to a third embodiment of the present invention. Referring to FIG. 12, as a total internal reflection prism, one rectangular prism 510 is provided. According to the present embodiment, the oblique surface 530 of the right angle prism 510 includes both an entrance surface 532 and an exit surface 534. The first side 520 of the rectangular prism 510 is oriented upward, and the fingerprint side is formed on the first side 520. A surface light emitting diode 540 for illuminating a fingerprint area is disposed at a portion adjacent to the first side surface 520 of the inclined surface 530, that is, the incident surface 532, and the remaining portion of the inclined surface 530, that is, the emission surface ( 534 is disposed with a sensor lens 550 for focusing the fingerprint image emitted through it and an image sensor 560 aligned with it.

The fingerprint recognition apparatus 500 according to the third embodiment uses a single right prism 510 and has a more compact structure because both the entrance surface 532 and the exit surface 534 are formed on the inclined surface. have.

The light emitted from the light emitting diode 540 is emitted in the form of surface emission so as to illuminate the full width of the fingerprint region formed on the upper surface of the total internal reflection prism 500. The surface light emission is irradiated to the fingerprint area through the entrance surface 532. In the fingerprint area, a predetermined fingerprint is restored as it is by the grease of the finger and is illuminated by the surface light emission. The illuminated fingerprint image is reflected by the first side 520 and the second side 522 of the total internal reflection prism 400 and exits the prism 500 through the exit surface 534. The fingerprint image leaving the prism 500 is collimated by the sensor lens 550 which is a condensing lens and imaged on the image sensor 560. The fingerprint image signal formed on the image sensor 560 is input to the data acquisition board 570 and converted into a digital signal. The fingerprint signal converted into the digital signal is recognized and separated into a point, a bifurcation, a line ending, an enclosure, and a short ridge by the ECU 580. Personal fingerprint information is stored in the ECU (not shown). The information stored as described above is used to determine the authenticity of each individual.

Fourth embodiment

13 shows a fingerprint recognition device 400 according to a third embodiment of the present invention. Referring to FIG. 13, an inverse triangular internal total reflection prism 420 is provided to transfer a fingerprint image.

Fingerprint region 410 is provided on the oblique side of prism 420. A surface light emitting diode 440 is provided on the incident surface 430 adjacent to the inclined surface to illuminate the fingerprint area 410. The other side of the prism 420 is an exit plane, where the illuminated fingerprint image exits out of the prism 420.

The light emitted from the light emitting diode 440 is emitted in the form of surface emission so as to illuminate the full width of the fingerprint region 410 formed on the internal surface of the total internal reflection prism 400. The surface light emission is irradiated to the fingerprint area 410 through the entrance surface 430. In the fingerprint area 410, a predetermined fingerprint is restored as it is by the grease of the finger and is illuminated by the surface light emission. The illuminated fingerprint image is reflected by the upper oblique surface of the total internal reflection prism 400 and exits the prism 400 through the exit surface 450. The fingerprint image leaving the prism 400 is collimated by the sensor lens 460 which is a condensing lens and imaged on the image sensor 470. The fingerprint image signal formed on the image sensor 470 is input to the data acquisition board 498 and converted into a digital signal. The fingerprint signal converted into the digital signal is recognized and separated into a point, a bifurcation, a line ending, an enclosure, and a short ridge by the ECU 499. Personal fingerprint information is stored in the ECU (not shown). The information stored as described above is used to determine the authenticity of each individual.

It can be seen that the fingerprint recognition device 400 according to the third embodiment is configured to be as compact as possible. Unlike the first and second embodiments, the fingerprint recognition device 400 emits a fingerprint image by one total internal reflection. Have

As described above, by combining one or two ejection prisms to recognize fingerprints by using total internal reflection thereof, there is an effect of replacing a plurality of mirrors, making the size of the entire optical system compact and easy to assemble.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. You can understand that you can.

Claims (17)

A surface light emitting diode, an image sensor in which a fingerprint image is formed, a data acquisition board for detecting the converted fingerprint image and converting the image into a digital signal, and an ECU for discriminating the digital signal. In the fingerprint recognition device having a control unit, The predetermined surface adjacent to the incident surface is provided with a fingerprint region through which light entering through the incident surface is incident, and includes an internal total reflection prism having an internal total reflection surface reflecting a fingerprint image illuminated by the light. Fingerprint identification device. The fingerprint recognition device according to claim 1, further comprising a sensor lens for focusing a fingerprint image reflected and emitted by the internal reflection surface of the total internal reflection prism. The internal reflection surface of claim 1, wherein the internal reflection surface is an internal total reflection mirror formed on each of the first, second, and third sides of the reflective prism that are sequentially bent at a predetermined angle with respect to each other from a side including the fingerprint area. Fingerprint recognition device, characterized in that. 4. The fingerprint recognition device according to claim 3, wherein a lens surface having a function of a lens is formed on the first, second, and third side surfaces or the exit surface. The apparatus of claim 4, wherein the lens surface is a spherical surface, an aspherical surface, or a toric surface. The fingerprint recognition apparatus of claim 1, wherein the image of the formed fingerprint is recognized by the ECU in a divided manner into dots, bifurcation, line endings, closed curves, and short lines. The fingerprint recognition apparatus according to claim 1, wherein the total internal reflection prism includes first and second rectangular prisms in which each of the oblique surfaces overlap each other with a predetermined area and are disposed up and down. The light emitting device of claim 7, wherein the first oblique surface of the first rectangular prism comprises an incident surface on which light from the light emitting diode is incident and a first attachment surface partially overlapping the second oblique surface of the second rectangular prism, A fingerprint region is provided on a first side facing the first attaching surface, and a second side between the first inclined surface and the first side is a first reflecting surface. The second and third side surfaces of the second rectangular prism are second and third reflection surfaces, respectively, except for a second attachment surface of the second inclined surface that faces the first attachment surface. And a surface is an exit surface from which the light reflected by the fingerprint area and the internal reflection surfaces exits the reflection prism. The fingerprint recognition device according to claim 9, wherein a lens surface having a function of a lens is formed on the first, second and third reflection surfaces, or the emission surface. The fingerprint recognition device according to claim 10, wherein the lens surface is a spherical surface, a symmetric torus, an asymmetric torus, or a cylindrical aspheric surface. 8. The fingerprint recognition device according to claim 7, wherein the image of the formed fingerprint is recognized by the ECU by being divided into a dot, a bifurcation, a line ending, a closed curve, and a short line. The fingerprint recognition apparatus of claim 1, wherein the total internal reflection prism includes one rectangular prism, and the oblique surface of the rectangular prism includes the incidence surface and the exit surface. The fingerprint light emitting device of claim 13, wherein a fingerprint region is formed on a first side of the rectangular prism, and a surface light emitting diode is disposed at a portion adjacent to the first side of the inclined surface, and a fingerprint emitted through the remaining portion of the inclined surface. And a sensor lens for focusing an image and the image sensor aligned with the image. delete delete delete