JP3328666B2 - Optical device and bill validator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device and a bill discriminating device for optically discriminating the type of a detected object and detecting the presence or absence of the object.

[0002]

BACKGROUND ART Although proposed various means have been made as a means for detecting the type determination or the presence or absence of the detected object,
As a typical example, an optical device that projects the projection light from the light emitting unit onto the surface of the detected object and receives the reflected light by the light receiving unit to detect the property of the detected object. A device for discriminating the type of an object or detecting the presence or absence of the object has been proposed.

FIG . 14 shows, by way of example, the basic principle of a conventional surface condition detecting device. For example, a projection light from an LED (Light Emitting Diode) a as a light emitting means is applied to the surface of a detection object b. The light is incident obliquely. A first light receiving element c as light receiving means for receiving a specular reflection component from the detected object b and a second light receiving element d for receiving a scattered reflection component are provided. Of the light receiving elements c and d are compared.

According to the surface condition detecting device shown in FIG. 14, when the surface of the detected object b is smooth, the amount of light incident on the first light receiving element c is equal to the amount of light incident on the second light receiving element d. Is relatively large with respect to. When the surface of the detected object b is rough, the amount of light incident on the second light receiving element d is relatively larger than the amount of light incident on the first light receiving element c. Therefore, the surface state of the detected object b can be detected based on the ratio of the electrical output from the first and second light receiving elements c and d.

[0005]

By the way, in the above-described conventional detecting device, the amount of light incident on the first light receiving element c greatly varies due to the position fluctuation and the inclination fluctuation of the detected object b. The light amount incident on the second light receiving element d is not so affected by the position change and the tilt change of the detected object b. Therefore, chromatic two light receiving elements c, an output ratio between d, position change and of the detected object, varies with the inclination variation, a problem that it is difficult to stably detect the surface state of the detected object are doing.

Furthermore, in the conventional sensing device, test
Although it is possible to determine the difference in the surface roughness of the surface of the known object , it is impossible to determine the type of the object to be detected (for example, a smooth metal surface or a glass surface), and therefore, the range of application as a surface state detection device is not possible. Is also narrow.

[0007] The present invention has been made in view of such a point, the position change and of the detected objects, less affected by the slope change, also be not only on the surface state of the detected object
It is an object of the present invention to provide an optical device and a bill discriminating device capable of detecting a difference in the material of a detected object and discriminating the type of the object and detecting the presence or absence of the object.

[0008]

According to a first aspect of the present invention, there is provided an optical device, comprising: an emitting unit that emits light to an object to be detected; and light reflected by the emitting unit that reflects the object. Or, light receiving means having an opening for receiving the scattered light partially scattered, or transmitted light transmitted through the detection object, non-parallel light is incident on the opening,
The size of the opening is small at a portion close to the light emitting means and large at a portion far from the light emitting means.

According to a second aspect of the present invention, there is provided a bill discriminating apparatus, comprising: an emitting means for emitting light to a detected object; and a light emitted by the emitting means reflected from the detected object, or a part of the reflected light. Light-receiving means having an opening for receiving scattered scattered light or transmitted light transmitted through the detected object; and a discriminating means for discriminating the type of a bill from light received by the light-receiving means. Means for separating any of the received light into a P-polarized component and an S-polarized component; and a plurality of photoelectric converters for receiving the P-polarized component and the S-polarized component separated by the separating means and converting them into electric signals. Conversion means, non-parallel light is incident on the opening, the size of the opening is small in a portion near the emission means, and large in a portion far from the emission means, the discrimination means is received by the photoelectric conversion means, the electric signal Converted to The determination is performed based on the electric signals corresponding to the P-polarized component and the S-polarized component.

[0010]

In the optical device according to the first aspect, light is emitted to the object to be detected, and reflected light reflected from the object to be detected, scattered light partially scattered, or transmitted through the object to be detected. Light is received as non-parallel incident light by a light receiving means having a small opening at a portion near the emitting means and a large opening at a portion far from the emitting means.

In the bill discriminating apparatus according to the second aspect, light is emitted to the detected object and reflected light reflected on the detected object, scattered light partially scattered, or transmitted through the detected object. The transmitted light is small in a portion close to the emission unit and is received as non-parallel incident light in a light receiving unit having a large opening in a portion far from the emission unit, and any of the received light is a P-polarized component. And the separated P-polarized component and S-polarized component are received and converted into an electric signal.Based on the converted electric signal corresponding to the converted P-polarized component and S-polarized component, Is determined.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic concept of an optical device to which the present invention is applied will be described with reference to FIG.

In FIG. 1, for example, an LED as a light emitting means for emitting light to a detected object 2 is provided in a housing 1.
The light emitted from the LED 3 is projected on the detected object 2 from an oblique direction. The projection light emitted to the detected object 2 is reflected by the detected object 2 and received by light receiving means arranged in the housing 1. The light receiving means includes a polarizing beam splitter 4 which is one of the polarizers, and is composed of first and second light receiving elements 5, 6. The polarization beam splitter 4 has a parallel flat plate made of a transmission glass material as a base, and a dielectric multilayer film including a dielectric or a metal film is formed on the incident side surface of the reflected light from the detected object 2. The reflected light incident from an oblique direction is split into two polarized light components orthogonal to each other. That is, the S-polarized light component is reflected on the surface of the polarization beam splitter 4 and
Is projected to The P-polarized light component passes through a parallel-plate base made of a transmission glass material and is projected on the second light receiving element 6.

In the above configuration, when the detected object 2 is a transparent body, the reflectance of the S-polarized component on the detected object 2 is larger than the reflectance of the P-polarized component. When the surface of the detected object 2 is a rough surface, the reflectances of the S-polarized component and the P-polarized component are substantially equal. Therefore, it is possible to determine whether or not the detected object 2 is a transparent body by calculating the output ratio from the two light receiving elements 5 and 6, and it is also possible to determine whether the surface of the transparent body (glass) is fogged or not. Also, when water droplets adhere, the surface state can be detected by the same principle.

At this time, even if the position of the detected object 2 fluctuates slightly or a slight inclination occurs, the light amounts of the S-polarized component and the P-polarized component incident on the two light receiving elements 5 and 6 similarly change. In addition, a change in the ratio between the outputs of the two light receiving elements 5 and 6 is small, so that stable detection is ensured.

The optical device shown in FIG. 1 may be configured as shown in FIG. That is, FIG. 2A is an example of a transmission type detection device in which the light projecting unit and the light receiving unit are separated. led
The light emitted from 3 is obliquely incident on the detected object 2 and is transmitted therethrough, and divides the transmitted light into two polarized light components orthogonal to each other, as in the optical device of FIG. .

In the above configuration, when the detected object 2 is a transparent body, the transmittance of the P-polarized light component in the detected object 2 is S.
It becomes larger than the transmittance of the polarized light component. Therefore, it is possible to determine whether or not the detected object 2 is a transparent body by taking the ratio of the outputs from the two light receiving elements 5 and 6, and if the object 2 is a transparent body having a different refractive index, Since the transmittance of the P-polarized light component and the transmittance of the S-polarized light component change, it is possible to distinguish between transparent bodies.

In addition, similarly to the optical device shown in FIG. 1, when a foreign substance adheres to the surface of the transparent body, the surface state can be detected.

FIG. 2B is a cross-sectional view when the detected object 2 is a plastic bottle.

In the configuration shown in FIG.
When it is determined whether or not is a transparent body, as described above, it is determined from the ratio of the light amount of the P-polarized light component and the light amount of the S-polarized light component. LE in which the light emission amounts of both polarization components are approximately equal
It is preferable to use D. However, when determining whether or not the polarization component is preserved upon reflection from the detected object, such as when determining the surface roughness of the surface of the detected object 2 such as the presence or absence of gloss, the light emission is performed. The light emitting element as a means mainly emits linearly polarized light, particularly P or S polarized light,
For example, it is desirable to use a semiconductor laser. In place of the semiconductor laser, P and S
A configuration may be adopted in which a polarizer 10 that transmits light in one direction of polarization is provided for the LED 3 that emits polarized light.

In particular, when a transparent substance such as glass is determined as an object to be detected, the incident angle α1 from the light emitting means to the object to be detected is preferably determined as follows. That is, FIG. 4 shows the angle dependence of the reflectance of glass. The vertical axis in FIG. 4 indicates the reflectance, and the horizontal axis indicates the incident angle α1 of the light from the light emitting means to the detected object, that is, the glass surface. Rs indicates the reflectance of the S-polarized component by the glass, and Rp indicates the reflectance of the P-polarized component.

As shown in FIG. 4, when the incident angle α1 is 50 to 60 degrees, the ratio of the reflectance of the S-polarized light component to the reflectance of the P-polarized light component, that is, Rs / Rp, is the largest. As shown in the figure, especially the angle of incidence of light from the light emitting means with respect to the glass surface
When α1 is 56.3 degrees (= αB ), Rp = 0. This α
B is generally called a Prewster angle. Therefore,
The incident angle α1 of the light from the light emitting means with respect to the glass surface is 4
If the positional relationship between the light emitting element as the light emitting means and the glass surface is set so as to be about 0 to 65 degrees, the transparent body (glass body) can be distinguished with high sensitivity.

FIG. 5 shows a basic configuration example of an optical device to which the present invention is applied. When an optical lens is not used as shown in FIG. 1, the reflected light from the detected object 2 is not transmitted or reflected by the polarizing beam splitter 4 and is not incident on one of the light receiving elements 5 and 6. The light receiving means needs to be provided with an opening 81 as shown in FIG. By providing the opening 81, by reflecting the detected object 2, light entering the light receiving means is limited, but the light entering the polarization beam splitter 4 is also limited to a certain degree, the diffusion shown by the arrow in FIG. 5 The reflected light enters the polarizing beam splitter 4 in a wider incident angle range than the specularly reflected light indicated by oblique lines in FIG. 5. If the reflected light is not properly polarized and separated, the S-polarized light component and the P-polarized light component become light receiving elements 5. , 6 are received by the light receiving element 5 or 6, and cannot be detected or discriminated correctly. Therefore, it is a necessary condition that the incident angle dependence of the reflectance or transmittance of the polarizing beam splitter 4 is small as shown in FIG.

FIG. 7 shows a specific configuration of the optical device of FIG. As shown in FIG. 7, in the case of a configuration using no lens, as described above, the light reflected from the detection target object 2 is polarized light beam splitter (Polarizing Beam Splitter).
(Hereinafter, also referred to as PBS.) An opening 81 is provided to prevent transmission or reflection of 4 or to receive only specularly reflected light as much as possible. In this case, an S-polarized component is received. When the light receiving element 5 is located on the side of the detected object 2 (closer to the opening 81), the volume of the entire apparatus can be reduced.

That is, as shown in FIG. 8, the PBS 4 separates the light incident at the central incident angle θ into P-polarized light and S-polarized light .
Shall be. At this time, considering that any light of the regular reflection light and the diffuse reflection light reflected by the detection target object 2 is transmitted or reflected by the PBS 4 and received by the light receiving elements 5 and 6, FIG.
It is necessary to bring an opening or a wall of the housing to the middle positions a , b , and c. When this is configured as shown in FIG. 9, the positions a , b , and c in FIG. Positions d , e , and f in FIG. 9 indicate that even if the same element is used, the volume of the device is greatly different. In the case of FIG. 9, the distance from the detected object 2 increases, so that the light use efficiency decreases.

In the configuration shown in FIG. 7, when discriminating between the detected objects 2 (for example, discriminating the type of paper, etc.) having a slight difference in the ratio between the P-polarized light component and the S-polarized light component contained in the reflected light, In the cases 5 and 6, an opening 81 is provided so as not to receive diffuse reflection light as much as possible, and the light incident on the light receiving elements 5 and 6 is restricted.
10A and FIG.
As shown in (b) , the size of the opening 81 is
In accordance with the beam diameter of the specularly reflected light when the light reflected through the aperture 81 is transmitted through the opening 81, the specularly reflected light can be efficiently received by reducing the size near the LED 3 and increasing the size farther away.

Here, the solid line in FIG. 10 (c) shows the range of the regular reflection component emitted from the LED 3 and received by the light receiving elements 5 and 6 when the detected object 2 is at a far position . )
The dotted line indicates the range of the specular reflection component when the detected object 2 approaches.
Since the range of the dotted line in the opening 81 is smaller than the range of the solid line, the opening 81
To form

Since the optical device of the present invention represented by FIG. 5 can determine the quality of paper and the quality of ink,
D. Discrimination of banknotes at an ATM vending machine or the like, particularly discrimination of fake bills, can be considered.

FIG. 11 shows a bill insertion slot F of such a device E.
Next, an embodiment of a bill discriminating apparatus for performing bill discrimination by disposing a detecting device A to which the optical device of the present invention is applied will be described. Detector A
Has a circuit section shown in FIG. 12 or 13, for example. That is, FIG. 12 shows, for example, the presence / absence detection of the detected object 2 by the ratio of the output from the light receiving element 5 for receiving the P-polarized component and the output from the light receiving element 6 for receiving the S-polarized component as shown in FIG.
5 is a block diagram illustrating an example of a circuit unit when performing type determination. FIG. FIG. 13 is a block diagram illustrating another example of the circuit unit in the case where detection or determination is performed using a signal of the difference / sum of two polarization components. As shown in FIG. 12 and FIG.
The circuit section includes amplifiers 71 and 72, a divider 73, a subtractor 7
4, 75, and a discriminator 76. When discrimination is made by the difference signal, the divider 73 is skipped to connect the points A and C. When discrimination is made by the sum signal, the divider 73 is skipped and the points B and C are discarded. Are connected.

[0030]

As described above, according to the optical device of the first aspect, the light emitting means for emitting light to the detected object, and the light from the light emitting means reflected, transmitted or diffused by the detected object. Light receiving means having an opening for receiving light,
The light receiving means is configured to individually receive mainly the P-polarized light component and mainly the S-polarized light component of the light from the detected object.
The output ratio of the light receiving element of the polarized light component does not fluctuate much, and a stable detection capability of the surface state is exhibited. Further, the type of the detected object (for example, a transparent body and a metal having a smooth surface) can be determined from the difference in the material, and the detection capability is increased.

According to the bill discriminating device of the present invention, the light is emitted to the detected object and the reflected light reflected on the detected object, the scattered light partially scattered, or the detected object is reflected. The transmitted light transmitted through is received by a light receiving means having an opening, and one of the received light is converted into a P-polarized component and S
Separate into polarized light components, receive the separated P and S polarized light components, convert them to electrical signals, and determine the type of banknote based on the converted electrical signals corresponding to the P and S polarized components. As a result, bills can be reliably discriminated, and discrimination of bills using a CD, an ATM vending machine or the like, particularly discrimination of a fake bill, can be performed.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a basic configuration of an optical device for explaining a basic concept of the present invention.

FIG. 2 is a side view showing another example of the basic configuration of the optical device for explaining the basic concept of the present invention.

FIG. 3 is a side view showing another configuration example of the light emitting unit used in the optical device shown in FIGS. 1 and 2;

FIG. 4 is a characteristic diagram showing reflection characteristics of a transparent material.

FIG. 5 is a side view showing a basic configuration of an optical device to which the present invention is applied.

6 is a characteristic diagram of the polarization beam splitter shown in FIG.

FIG. 7 is a longitudinal sectional view showing a specific configuration of the optical device of FIG. 5;

8 is an optical path diagram showing an example of an optical path in the configuration shown in FIG.

9 is an optical path diagram showing another example of the optical path in the configuration shown in FIG.

FIG. 10 is an explanatory view showing the shape of the opening shown in FIG. 5;

FIG. 11 is a perspective view showing a bill discriminating apparatus to which the present invention is applied.

FIG. 12 is a block diagram illustrating a configuration of a circuit unit using the optical device of FIG. 5;

FIG. 13 is a block diagram showing a configuration of a modification of the circuit section shown in FIG.

FIG. 14 is a diagram showing a configuration of an example of a conventional optical device.
You.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Detected object 3 Light emitting element (light emitting means) 4 Polarizing beam splitter 5 Light receiving element (light receiving means) 6 Light receiving element (light receiving means) 81 Aperture A detector

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hironobu Kiyomoto Examiner Emi Tanabe in Omron Co., Ltd. 10 at Hanazono Todocho, Ukyo-ku, Kyoto-shi, Kyoto (56) References JP-A-63-52284 (JP, A) JP-A-5-133811 (JP, A) JP-A-5-26725 (JP, A) JP-A-1-305340 (JP, A) JP-A-59-228128 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01J 1/00-1/60

Claims (2)

(57) [Claims] An emission unit that emits light to an object to be detected, and light emitted by the emission unit is reflected light reflected on the object to be detected, or scattered light partially scattered, or Light receiving means having an opening for receiving the transmitted light transmitted through the object to be detected, non-parallel light is incident on the opening, and the size of the opening is small at a portion close to the emitting means; An optical device characterized in that it is large in a portion far from the means. 2. An emitting means for emitting light to an object to be detected, and light emitted by the emitting means is reflected light reflected on the object to be detected, or scattered light partially scattered, or A light receiving unit having an opening for receiving the transmitted light transmitted through the detected object; and a discriminating unit for discriminating the type of a bill from the light received by the light receiving unit. A separating unit that separates any one of the P-polarized component and the S-polarized component, and a plurality of photoelectric conversion units that receive the P-polarized component and the S-polarized component separated by the separating unit and convert the received light into an electric signal. , Non-parallel light is incident on the opening, and the size of the opening is
Small in the portion close to the emitting means and far from the emitting means
The bill is characterized in that the discriminating means performs discrimination based on the electric signals corresponding to the P-polarized light component and the S-polarized light component, which are received by the photoelectric conversion means and converted into electric signals. Discriminator.