JP2001283207A - Image reader, its method and device applying the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a handy image reader capable of accurately reading both of a rugged reading object such as fingerprints and a reading object such as a document with gradation by using a linear photoelectric conversion element. SOLUTION: An input member 3 has an input surface 2 and a surface 19 parallel with the input surface 2, a finger 1 is placed on the input surface 2 in reading fingerprints, and the finger 1 is moved in the direction indicated by the arrow to composite an entire image from partial images. A linear photoelectric conversion element 5 is located at a position to receive reflected light regulated by Snell's law from the input surface on the opposite side of a light source 4. Incident light from the light source 4 has illuminace equal to or larger than a certain value in an incident angle range of 20 from the critical angle of the linear region of the input surface 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear, rectangular or one-dimensional image which is composed of a linear, rectangular or one-dimensional image by means of a linear, rectangular or one-dimensional photoelectric conversion element and which is relatively moved by an image reader. The present invention relates to an image reading device, an image reading method, and an application device thereof, which can read both an object to be read having unevenness such as a fingerprint and an object having light and shade such as characters, figures, and pictures.

[0002]

2. Description of the Related Art Conventionally, fingerprint reading utilizes the difference in reflected light due to the difference in the state of skin contact between valleys and mountains when a finger is imprinted on an optical member having a transparent input surface such as glass. . That is, as shown in FIG. 4, when the finger 1 is impressed on the input surface 2 to be read of the triangular prism 13 as an input member made of glass, synthetic resin, or the like, the mountain portion comes into contact with the right-angle prism and the skin, but the valley. Is in contact with air, so if the incident angle exceeds the critical angle at the interface between the right-angle prism and air, total reflection occurs at the valley, and a large difference in reflectance occurs between the valley and the valley. Are read as a light and shade pattern.

However, in the method utilizing the total reflection at an incident angle exceeding the critical angle as described above, the reading of an object such as paper, for which complete optical contact cannot be obtained, for example, the reading of an original, is performed because of the total reflection. Absent.

[0004] Therefore, the entire image is synthesized from the linear partial image by the relative movement of the object to be read and the image reading device having a linear photoelectric conversion element (or a so-called line sensor, linear sensor, or the like) as a light receiving element. Japanese Patent Application Laid-Open No. H10-240906 discloses an example of an image reading apparatus for reading a fingerprint and an original by detecting illumination light vertically incident on an input surface.

The method of synthesizing the whole image from the linear partial image by the relative movement of the object to be read and the image reading apparatus having the linear photoelectric conversion element can reduce the size of the apparatus.

[0006]

According to the method using the normal incidence and reflection, the reading of the original is easy, but the difference in the reflected light between the peaks and valleys of the finger is significantly inferior to that of the total reflection, so that the fingerprint reading accuracy is low. not so good.

Accordingly, the present invention uses a linear photoelectric conversion element, and can accurately read both an object to be read having irregularities such as a fingerprint and an object having shading such as a manuscript or characters, figures, and pictures. An object of the present invention is to provide a simple image reading device.

[0008]

According to the present invention, illumination light is incident on an input surface to be read at an angle of incidence smaller than the critical angle at which total reflection occurs and at least 20 degrees.

Thus, the difference in reflected light between the peak and the valley at the time of fingerprint detection can be made higher than the vertical incidence / reflection, and the original can be read.

[0010] A photoelectric conversion element as a light receiving element is placed at a position for receiving reflected light reflected from the light source on the input surface of the input member according to Snell's law.

In this way, the fingerprint detection is performed by reflected light, and when reading an original or the like, scattered light incident on the photoelectric conversion element from the object to be read at the same angle as the reflected light can be received, and both fingerprint detection and original reading can be performed with high accuracy. I can do it.

Further, a plurality of photoelectric conversion elements are provided at different light receiving positions.

By changing the light receiving position between the time of fingerprint detection and the time of reading a document or the like, it is possible to avoid the influence of reflected light when reading the document.

Alternatively, the input member having an input surface to be read may be a triangular prism, a trapezoidal prism, a semi-cylindrical prism, or a V-shaped prism.
By using an optical member having a shape groove, the structure can be simplified.

By providing an imaging optical system between the input member and the photoelectric conversion device, the size of the photoelectric conversion element can be reduced.

Further, an optical fiber bundle in which a number of optical fibers are bundled is provided between the input member and the photoelectric conversion device. As a result, the influence of scattered light incident on the optical fiber bundle at a large incident angle can be eliminated, the degree of freedom of the optical path increases, and the size of the apparatus can be reduced.

Further, the optical member having a triangular prism, a trapezoidal prism, a semi-cylindrical or V-shaped groove is made of synthetic resin, so that it can be easily manufactured at low cost.

In addition, there is provided a light source for illumination, an input member having an input surface to be read, and a linear photoelectric conversion element, and light incident on the input surface from the light source is not less than 20 degrees and less than the critical angle. An image reading device having an angle component synthesizes the entire image from the linear partial images by the relative movement of the reading object and the image reading device.

Thus, it is possible to realize an image reading apparatus having a simple structure capable of accurately reading both an object to be read having unevenness such as a fingerprint and an object having light and shade such as a manuscript by a linear photoelectric conversion element.

Further, by integrating a portable wireless communication device such as a portable telephone, a PHS, or the like, a portable information device such as a portable information terminal or an electronic organizer with the image reading device, fingerprint authentication, characters, and figures can be obtained with a simple structure. It is possible to input information in shades of light.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an incident angle of incident light from a light source to an input surface of an image reading apparatus according to the present invention.

One surface of the input member 3 serves as the input surface 2. For example, in the case of fingerprint input, the finger 1 is pressed.

The light source is on the opposite side of the input surface from the object to be read, and light incident on the input surface is changed from the maximum incident angle 6 to the minimum incident angle 8
The illuminance is at least a certain value or more within the range of the incident range 7.

Here, the maximum incident angle is an angle at which the reflected light with respect to the incident light from the input member 3 to the input surface 2 side is totally reflected, that is, an angle smaller than the critical angle.

The minimum incident angle is 20 degrees.

That is, 20 degrees ≦ the incident angle of the incident light from the light source to the input surface <the critical angle. The input member may be glass or synthetic resin, but the refractive index thereof is in the range of 1.5 to 2.

FIG. 2 is a diagram showing an incident angle-reflectance characteristic when glass or a synthetic resin is used as an input member.

The reflectance curve 9 indicates that the refractive index of the input member is 1.
5. The reflectance curve 10 is for the case where the input member has a refractive index of 2 and is in contact with air.

The reflectance curve 11 is obtained when the input member has a refractive index of 2 and comes into contact with the skin.

When in contact with the skin, the reflectivity hardly changes up to an incident angle of 40 degrees, and although not shown, the refractive index is 1.5.
But the same is true.

On the other hand, when in contact with air, the critical angle is about 41.8 degrees at a refractive index of 1.5, and the critical angle decreases as the refractive index increases. The angle is 30 degrees.

When the refractive index is 2, the reflectivity sharply increases at an incident angle of 20 degrees. Therefore, the incident light is within a range of 20 degrees from the critical angle and has an illuminance of a certain value or more. Good.

As described above, when the incident light has an illuminance not less than a certain value within the range of 20 degrees or less at the critical angle, the contrast of the light reflected from the valley and the hill on the input surface at the time of fingerprint input is the same as that at the time of vertical incident reflection. Be larger.

On the other hand, since there is no total reflection, there is a certain amount of transmitted light, and it is possible to read an original by scattered light from paper or the like.

FIG. 3 is a diagram showing an embodiment of the image reading apparatus of the present invention.

There is an input member 2 having an input surface 2 and a surface 19 parallel to the input surface.
Is stamped. In the case of reading an original, it is of course paper.

On the opposite side of the light source 4, there is a linear photoelectric conversion element 5 as a light receiving element.

By moving the finger 1 in the direction of the arrow,
The whole image is synthesized from the partial images.

Since the photoelectric conversion element is linear, the incident light may have an illuminance not less than a value in the range of 20 degrees from the critical angle in the corresponding linear region of the input surface.

The linear photoelectric conversion element 5 is located at a position for receiving reflected light defined by Snell's law from the input surface.

That is, the incident angle 12 of the light source 4 is set to be substantially the same as the detection angle 13 of the linear photoelectric conversion element 5.

The reflected light referred to in the present invention is a reflected light that follows the Snell's law at the interface of the input surface of the input member with incident light from the light source when the light source is on the opposite side of the input surface from the object to be read. The light refers to light that has passed through the input member by incident light from a light source and has been reflected at the skin or paper of a finger or at the interface between air and skin or at the interface between paper and air and has returned to the input member side.

Since this scattered light is subjected to multiple reflections, it spreads over a wide angle. If the incident light for illumination is smaller than the critical angle, total reflection does not occur from the input surface side to the input member. Therefore, it can be detected at almost any position.

That is, by making the angle of incidence 12 of the light source 4 substantially equal to the angle of detection 13 of the linear photoelectric conversion element 5, reflected light is used for fingerprint detection and diffused light is used for document reading. Both fingerprint and document reading are possible.

In the present invention, the peak direction of the emitted light from the light source slightly deviates from the direction of the incident light, or the peak direction of the reflected light deviates slightly from the normal direction of the detection surface of the linear photoelectric conversion element. This is not a problem.

It is an object of the present invention that incident light having a certain value or more is incident at a predetermined incident angle, and reflected or scattered light having a certain value or more is detected.

FIG. 15 shows a photoelectric conversion element 5 as a light receiving element.
Is a case where two light receiving angles are set.

One light receiving element is placed at a position for receiving reflected light for detecting a fingerprint, and the other light receiving element is shifted from the position for receiving reflected light to be used for reading an original or the like, so that the influence of reflected light when reading an original or the like is reduced. It can be avoided and accuracy is improved.

FIG. 4 shows an example in which a triangular prism 14 is used as an input member. Since the incidence from the light source 4 to the surface of the triangular prism and the emission of reflected light or scattered light are perpendicular, the configuration is simplified.

FIG. 5 shows a modification of the triangular prism 14 as an input member.

The flattened corners make it easier to use. Such modifications are basically included in the spirit of the present patent.

FIG. 6 shows a case in which the optical path of the incident light from the light source 4 and the reflected / scattered light is changed by the mirror 15. For example, in this case, the light source 4 and the linear photoelectric conversion element 5 are placed almost immediately below the input surface. And miniaturization becomes possible.

FIG. 7 shows a configuration in which a trapezoidal prism 16 is used as an input member, and the role of the mirror 14 is performed on the side surface of the prism.

FIG. 8 also uses the triangular prism 14 as an input member, changes the optical path of the incident light from the light source 4 and the reflected / scattered light by the mirror 15, and makes the light source 4 and the linear photoelectric conversion element 5 face each other, and is almost the same. An example of installation on a surface enables thinning.

FIG. 9 shows an example in which the V-groove surface of the input member 3 having the V-groove 20 is used as the mirror 15 so that the light source 4 and the linear photoelectric conversion element 5 face each other and are installed on substantially the same plane. Becomes easier.

FIG. 12 shows a case where the input member 3 has a semi-cylindrical shape.

As shown in FIG. 13, a semi-cylindrical input member is incident perpendicularly to incident light from any direction, and the design is simpler than in the case of a plate or prism.

If the input member having the triangular prism, the trapezoidal prism, the semi-cylindrical shape, and the V-groove is made of a synthetic resin, even an optical member having such a complicated and high precision can be easily reduced by injection molding, press molding or the like. It is very convenient because it can be manufactured at low cost.

FIG. 10 shows a triangular prism 1 as an input member.
When the imaging optical system 17 is provided between the linear photoelectric conversion device 4 and the linear photoelectric conversion device 5, the size of the photoelectric conversion element can be reduced.

In this case, the input member is not limited to the triangular prism.

FIG. 11 shows a triangular prism 1 as an input member.
In the case where the optical fiber bundle 18 is provided between the optical fiber 4 and the linear photoelectric conversion device 5, the influence of scattered light incident on the optical fiber bundle at a large incident angle can be removed, and the degree of freedom of the optical path is increased. The size of the device can be reduced.

In the case of fingerprint reading, it is easy to fix the reading device and move the finger, and to read a document or the like, it is easy to operate the reading device by moving the reading device.

FIG. 14 shows an example of an application apparatus according to the present invention. The image reading apparatus 21 according to the present invention is integrally incorporated in a portable telephone. And data of figures and illustrations can be read.

Further, by integrating a portable wireless communication device such as a portable telephone or a PHS or a portable information device such as an amusement device, a portable information terminal or an electronic organizer with the image reading device, fingerprint authentication can be performed with a simple structure. And information in shades of characters, figures, etc. can be input.

In the above description, the name of the linear photoelectric conversion element has been mainly used. However, the linear photoelectric conversion element of the present invention may be referred to as a one-dimensional or rectangular photoelectric conversion element or the like, or a line sensor or a linear sensor. Including what is called 1
It includes all light receiving elements for synthesizing an entire image from a dimensional, linear, or rectangular partial image.

[0067]

As described above, according to the present invention, an input member having a light source, an input surface, and a linear photoelectric conversion element are provided, and the light incident on the input surface from the light source is at least 20 degrees. With an image reading device having an angle component smaller than the critical angle, by synthesizing the whole image from the linear partial image by the relative movement of the reading object and the image reading device, an uneven reading object such as a fingerprint, It is possible to obtain a small-sized image reading apparatus capable of reading both objects having a light and shade such as a document and a document.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an incident angle of incident light from a light source to an input surface of an image input device.

FIG. 2 is a diagram showing an incident angle-reflectance characteristic.

FIG. 3 is a diagram illustrating an image reading device.

FIG. 4 is a diagram illustrating an image reading device.

FIG. 5 is a diagram illustrating an image reading device.

FIG. 6 is a diagram illustrating an image reading device.

FIG. 7 is a diagram illustrating an image reading device.

FIG. 8 is a diagram illustrating an image reading device.

FIG. 9 is a diagram illustrating an image reading device.

FIG. 10 is a diagram illustrating an image reading device.

FIG. 11 is a diagram illustrating an image reading apparatus.

FIG. 12 is a diagram illustrating an image reading device.

FIG. 13 is a diagram illustrating an image reading device.

FIG. 14 is a diagram showing an application device of the present invention.

FIG. 15 is a diagram illustrating an image reading device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 finger 2 input surface 3 input member 4 light source 5 photoelectric conversion element 6 maximum incident angle 7 incident range 8 minimum incident angle 9, 10, 11 reflectance curve 12 incident angle 13 detection angle 14 triangular prism 15 mirror 16 trapezoidal prism 17 imaging Optical system 18, 19 Optical fiber bundle 20 V groove 21 Image reader

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Machida 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc.

Claims (15)

[Claims] 1. An image reading apparatus comprising: a light source, an input member having an input surface to be read, and a linear photoelectric conversion element, wherein an incident angle of incident light from the light source to a linear region of the input surface is 20. An image reading apparatus having an incident angle component that is greater than or equal to degrees and smaller than a critical angle, and synthesizes an entire image from a linear partial image by the relative movement of the reading object and the image reading apparatus. 2. The image reading apparatus according to claim 1, wherein the reading target is a reading target having irregularities such as a fingerprint and a reading target having shades such as characters and pictures. 3. The image reading apparatus according to claim 1, wherein the photoelectric conversion element is located at a position for receiving the reflected light of the incident light defined by Snell's law from the input surface of the input member. . 4. An image reading apparatus according to claim 1, wherein said photoelectric conversion element comprises a plurality of light-receiving positions different from each other. 5. The image reading apparatus according to claim 1, wherein said input member is a triangular prism. 6. The image reading apparatus according to claim 1, wherein said input member is a trapezoidal prism. 7. The image reading apparatus according to claim 1, wherein said input member has a semi-cylindrical shape. 8. An image reading apparatus according to claim 1, wherein said input member is an optical member having a V-shaped groove. 9. An image reading apparatus according to claim 1, further comprising an image forming optical system between said input member and said photoelectric conversion element. 10. The image reading apparatus according to claim 1, further comprising an optical fiber bundle between said input member and said photoelectric conversion element. 11. The image reading apparatus according to claim 5, wherein said input member is made of a synthetic resin. 12. An input member having a light source, an input surface to be read, and a linear photoelectric conversion element, wherein light incident on the input surface from the light source is an angle component of 20 degrees or more and smaller than a critical angle. An image reading method, comprising: synthesizing an entire image from a linear partial image by a relative movement of a reading target and the image reading device using the image reading device. 13. The image reading method according to claim 11, wherein the reading target is a reading target having irregularities such as a fingerprint, and a reading target having shades such as characters and pictures. 14. An input member having a light source, an input surface to be read, and a linear photoelectric conversion element, wherein light incident on the linear region of the input surface from the light source has an incident angle of 20 degrees or more, and An object having an incident angle component smaller than a critical angle, wherein the object to be read is an object to be read having unevenness such as a fingerprint, and an object to be read having shades such as characters and pictures; A portable wireless communication device having an integrated image reading device that synthesizes an entire image from a linear partial image by moving. 15. An input member having a light source, an input surface to be read, and a linear photoelectric conversion element, wherein light incident on the linear region of the input surface from the light source has an incident angle of 20 degrees or more, and An object having an incident angle component smaller than a critical angle, wherein the object to be read is an object to be read having unevenness such as a fingerprint, and an object to be read having shades such as characters and pictures; A portable information device having an integrated image reading device that synthesizes an entire image from a linear partial image by moving.