JPH0798247A - Optical device - Google Patents

Abstract

PURPOSE:To provide an optical device which is less affected by the position fluctuation and inclination fluctuation of an object to be detected and can discriminate the type of the object to be detected and detect its presence or absence. CONSTITUTION:An LED 3 is laid out inside an enclosure 1 as a light emitting means for emitting light to an object 2 to be detected and light emitted from the LED 3 is projected from the oblique direction for the object 2 to be detected. Projection light emitted to the object 2 to be detected is reflected by the object 2 to be detected and is received by a light reception means which is laid out inside the enclosure 1. The light reception means is constituted of a polarization beam splitter 4 and first and second photodetector 5 and 6. The polarization beam splitter 4 reflects S polarization constituents out of reflection light entering in oblique direction on the surface of the polarization beam splitter 4 and then projects it to the first photodetector 5. Also, P polarization constituent is transmitted through the polarization beam splitter 4 and is projected to the second light reception element 6.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Various means have been proposed as means for detecting the type or presence / absence of a detected object.
As a typical example, the projection light from the light emitting means is projected onto the surface of the object to be detected, and the reflected light is received by the light receiving means to detect the property of the object to be detected. There has been proposed an object type discrimination or presence / absence detection device.

FIG. 38 shows, as an example, the basic principle of a conventional surface state detecting device. Projection light from, for example, an LEDa as a light emitting means is incident obliquely on the surface of an object b to be detected. To be done. A first light receiving element c as a light receiving means for receiving the specular reflection component from the detected object b and a second light receiving element d for receiving the scattered reflection component are provided, and the first and second The electric outputs from the respective light receiving elements c and d are compared.

According to the surface state detecting device shown in FIG. 14, when the surface of the object b to be detected is smooth, the amount of light incident on the first light receiving element c is the amount of light entering the second light receiving element d. Relative to Further, 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 condition of the detected object b can be detected by the ratio of the electrical outputs from the first and second light receiving elements c and d.

[0005]

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

Further, in the conventional detection device, although the difference in surface roughness of the surface of the object to be detected can be discriminated, it is not possible to discriminate the kind of the object to be detected (for example, smooth surface metal and glass surface). However, there is a problem that the application range of the surface state detection device is narrow.

The present invention has been made paying attention to such a point, and it is less affected by the position variation and the inclination variation of the detected object, and the surface state of the detected object as well as the detected object An object of the present invention is to provide an optical device capable of detecting the difference in material and discriminating the type of an object and detecting the presence or absence of the object.

[0008]

An optical device according to claim 1, which is formed to achieve the above object, comprises, for example, an LED as a light emitting means for emitting light to an object to be detected,
In an optical device including a light receiving unit that receives light from a light emitting unit that reflects, transmits, or is partially scattered by the detected object, the light receiving unit is the light from the detected object or the light receiving unit. It is characterized in that a plurality of polarization components of the light partially scattered by the detection object are separately received.

According to another aspect of the optical device of the present invention, the light receiving means is mainly P, out of reflected light from the object to be detected, transmitted light, or light partially scattered by the object to be detected.
The polarized light component and mainly the S polarized light component are individually received.

According to another aspect of the optical device of the present invention, the light receiving means is mainly P out of reflected light from the object to be detected, transmitted light, or light partially scattered by the object to be detected.
It is characterized by comprising a plurality of light receiving elements including a light receiving element which receives a polarized light component and a light receiving element which mainly receives an S polarized light component.

An optical device according to a fourth aspect is characterized in that the light receiving means has a plurality of light receiving elements arranged in one package.

An optical device according to a fifth aspect of the invention is characterized in that the light receiving means is formed by dividing one chip into a plurality of light receiving elements.

An optical device according to a sixth aspect is characterized in that the light receiving element is an optical fiber.

An optical device according to a seventh aspect is characterized in that the light emitted from the light emitting means is incident on the surface of the object to be detected in an oblique direction.

The optical device described in claim 8 is characterized in that the incident angle of the light emitted from the light emitting means with respect to the object to be detected is 50 degrees or more.

An optical device according to a ninth aspect is characterized in that the incident angle of the light emitted from the light emitting means with respect to the detected object is in the vicinity of the Brewster angle.

An optical device according to a tenth aspect is characterized in that the light emitted from the light emitting means near the optical axis is emitted substantially perpendicularly to the surface of the object to be detected. .

In the optical device according to the eleventh aspect of the present invention, the light emitting means and the light receiving means are present in different housings, and when there is no object to be detected, the light from the light emitting means is directly received by the light receiving means. It is characterized by

In the optical device according to the twelfth aspect, the light from the light emitting means is obliquely incident on the surface of the object to be detected,
The light receiving means is characterized by receiving the light transmitted through the detected object.

The optical device according to the thirteenth aspect is characterized in that the light receiving means is arranged at a position for receiving the specular reflection component from the detected object.

According to a fourteenth aspect of the present invention, the light emitting means is characterized in that the light intensity of the P-polarized component and the light intensity of the S-polarized component emitted to the object to be detected are substantially equal.

According to a fifteenth aspect of the present invention, in the light emitting means, the light emitted to the object to be detected is mainly P-polarized component or mainly S-polarized component.

In the optical device according to the sixteenth aspect, the light emitting means includes a light emitting element and light emitted from the light emitting element.
It is characterized in that it is mainly composed of a P-polarized component or a polarizer that mainly extracts an S-polarized component.

An optical device according to a seventeenth aspect is characterized in that the light emitted from the light emitting means is applied to the object to be detected through the collimating means by an optical lens.

The optical device according to the eighteenth aspect is characterized in that the light emitted from the light emitting means is applied to the object to be detected as divergent light or convergent light through the optical lens.

In the optical device according to the nineteenth aspect of the invention, the light receiving means separately receives a plurality of reflected light from the object to be detected, transmitted light, or light partially scattered by the object to be detected. It is composed of an element, a light receiving element, and an analyzer which is disposed between the object to be detected and mainly extracts light of different polarization directions from light from the object to be detected or light partially scattered by the object to be detected. It is characterized by

In the optical apparatus according to the twentieth aspect of the invention, the light receiving means separately receives a plurality of reflected light from the object to be detected, transmitted light, or light partially scattered by the object to be detected. An element, a light-receiving element, and a detection object, which are arranged between the detection object and reflected light, transmitted light, or light partially scattered by the detection object, are mainly used as P-polarized components, respectively. It is characterized in that it is mainly composed of a polarization beam splitter for separating it into S-polarized components.

In the optical device according to the twenty-first aspect, the light receiving means separately receives the reflected light from the detected object, the transmitted light, or the light partially scattered by the detected object. Which is arranged between the element, the light receiving element and the object to be detected, and which is mainly reflected by the object to be detected, transmitted light, or light partially scattered by the object to be detected is mainly a P-polarized component and Is disposed between the polarization beam splitter and the object to be detected, and the reflected beam from the object to be detected, the transmitted light, or the light partially scattered by the object to be detected is converged. It is characterized by being configured with an optical lens.

An optical device according to a twenty-second aspect is characterized in that the polarization beam splitter has a small incident angle dependency of reflectance in a desired incident angle range.

The optical device according to the twenty-third aspect is characterized in that the polarization beam splitter is formed by forming a dielectric multilayer film including a dielectric or a metal film on the surface of a parallel plate.

The optical device according to the twenty-fourth aspect is characterized in that the center value of the incident angle range of the light to the polarization beam splitter is near the Brewster angle.

In the optical apparatus according to the twenty-fifth aspect, the polarization beam splitter reflects the S-polarized component, and the light-receiving element that receives the S-polarized component is present closer to the detected object than the light-receiving element that receives the P-polarized component. Is characterized by.

In the optical device according to the twenty-sixth aspect, in the light receiving means, when at least the surface of the object to be detected is made of a transparent or semitransparent substance, reflected light from the front and back surfaces of the transparent or semitransparent substance is used. It is characterized by comprising a plurality of light receiving elements for respectively receiving light.

In the optical device according to the twenty-seventh aspect, the non-parallel light is incident on the light receiving means, the light receiving means is provided with an opening, and the size of the opening is small near the light emitting means and far away from the light emitting means. Characterized by being large.

In the optical device according to the twenty-eighth aspect, when the object to be detected does not exist, the light receiving means receives the reflected light from the light emitting element which reflects the background object, and the surface of the background object is made of a material containing at least a dielectric. Is characterized in that.

According to a twenty-ninth aspect of the invention, in the optical device according to the twenty-ninth aspect, when there is no object to be detected, the light receiving means receives the reflected light from the light emitting element which reflects the background object, and the background object emits at least the light emitted from the light emitting means. It is characterized in that the portion hit by is a uniform shape or a uniform material.

In the optical apparatus according to the thirtieth aspect, the optical apparatus sets a determination threshold value by sensing a part or all of several kinds of detected objects which should be determined at a predetermined timing or when a command is given. It is characterized by automatic setting or automatic correction.

According to a thirty-first aspect of the present invention, in the optical device, the presence or absence of the object to be detected is determined by the ratio, sum, difference, difference / sum of the amounts of light of different polarization components received by the plurality of light receiving elements,
Alternatively, it is characterized by judging the type.

An optical device according to a thirty-second aspect of the invention is characterized by determining whether or not the detected object is a transparent body.

The optical device described in (33) is characterized in that the object to be detected is paper or film, and at least the type thereof is discriminated.

An optical device according to a thirty-fourth aspect is characterized in that the presence or absence of gloss on the surface of the object to be detected is determined.

An optical device according to a thirty-fifth aspect is characterized in that it is determined whether or not a foreign matter is attached to the surface of the object to be detected, or whether or not the foreign matter is attached to the background object. To do.

An optical device set forth in (36) is characterized by determining whether or not the surface of the detected object is cloudy.

An optical device according to a thirty-seventh aspect is characterized in that it is determined whether or not water droplets are attached to the detected object, or whether or not frost is attached to the background object. .

An optical device according to a thirty-eighth aspect is characterized in that it is determined whether or not frost is attached to the detected object, or whether or not water droplets are attached to the background object.

The optical device described in Item 39 is characterized in that the object to be detected is a suspended matter or particles in the air.

[0047]

In the optical device having the above structure, light is emitted from the light emitting element such as an LED as the light emitting means to the object to be detected, and the light reflected, transmitted or scattered by the object to be detected is mainly P The polarized light component and mainly the S polarized light component are individually received by the light receiving means. The P-polarized light component and the S-polarized light component which are orthogonal to each other are individually received and the light-receiving outputs thereof are compared to each other, whereby the change in the output ratio of the two light-receiving elements with respect to the position change and the tilt change of the detected object can be reduced. Stable detection ability of the surface state is exhibited. Further, even for objects having the same surface roughness, it is possible to determine the type of the object to be detected (for example, a transparent body and a metal having a smooth surface) due to the difference in material, and the detection capability is increased.

Further, the light emitted from the light emitting means to the object to be detected is mainly formed into either the P-polarized component or the S-polarized component, so that the surface condition of the object to be detected (smooth surface or rough surface) It is possible to increase the detection capability of).

[0049]

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

FIG. 1 is a first embodiment showing the basic concept of the optical device of the present invention. In the housing 1, for example, an LED 3 as a light emitting means for emitting light to the object 2 to be detected is provided. The light emitted from the LED 3 is arranged so as to be obliquely projected onto the detected object 2. Detected object 2
The projection light emitted to is reflected by the object 2 to be detected and is received by the light receiving means arranged in the housing 1. This light receiving means is composed of a polarizing beam splitter 4 which is one of polarizers, and first and second light receiving elements 5 and 6. The polarization beam splitter 4 has a parallel plate made of a transparent glass material as a substrate, and a dielectric multilayer film including a dielectric or a metal film is formed on a surface of an incident side of reflected light from the detected object 2. The reflected light that is incident from an oblique direction is split into two polarized light components that are orthogonal to each other. That is, the S-polarized component is reflected on the surface of the polarization beam splitter 4 and projected on the first light receiving element 5. Further, the P-polarized component is transmitted through the parallel plate base made of a transparent glass material and projected on the second light receiving element 6.

In the above structure, when the object 2 to be detected is a transparent body, the reflectance of the S-polarized component on the object 2 to be detected is higher than the reflectance of the P-polarized component. Further, when the surface of the object to be detected 2 is rough, the reflectances of the both polarization components are substantially equal. Therefore, the two light receiving elements 5,
By taking the ratio of the outputs from 6, it is possible to determine whether or not the detected object 2 is a transparent body, and also when the surface of the transparent body (glass) becomes cloudy or when water drops adhere. The surface state can be detected by the same principle.

At this time, even if the position of the object to be detected 2 slightly changes or the inclination slightly changes, the light amounts of the S-polarized component and the P-polarized component incident on the two light-receiving elements 5 and 6 are the same. There is little change in the ratio of the outputs of the two light receiving elements 5 and 6, and thus stable detection is guaranteed.

FIG. 2A shows the configuration of the second embodiment of the present invention, which is an example of a transmission type detection device in which a light projecting portion and a light receiving portion are separated. The light emitted from the LED 3 is obliquely incident on and transmitted through the object 2 to be detected, and, like the first embodiment, splits the transmitted light into two polarized light components orthogonal to each other. .

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

In addition, as in the case of the first embodiment, even if a foreign substance adheres to the surface of the transparent body, its surface condition can be detected.

FIG. 2 (b) is a sectional view when the detected object 2 is a PET bottle.

FIG. 3 is a third embodiment to which the second embodiment is applied, and the semiconductor laser LD3a is used so as to mainly emit P-polarized light or S-polarized light from the light emitting portion.
Then, this light is received by the two light receiving elements 5 and 6 in the light receiving section.
The light is received by, but when the detected object 2 does not exist,
There is almost no output from one light-receiving element that receives P- or S-polarized light, but an object 201 that scatters light in this optical path (rain, snow, fog, or foreign matter smaller than the beam diameter, or a rough surface) If there is a transparent body, the outputs of the two light receiving elements 5 and 6 change, and the presence thereof can be detected.

The fourth embodiment shown in FIG. 4 shows, as an example of the light receiving means, a state in which the light receiving element chips are housed in one package. In this, the independent light receiving element chips constituting the first and second light receiving elements 5 and 6 are molded with a transparent plastic material to form a package 7. When molding each light receiving element chip with a plastic material, the output electrodes 8 of each light receiving element chip are led out at both ends thereof.

In the fifth embodiment shown in FIG. 5, as another example of the light receiving means, one light receiving element chip is divided into two, and the first and second light receiving elements 5 and 6 are formed respectively. Similar to the example of FIG. 4, the package 7 is formed by molding with a transparent plastic material. Further, when the light receiving element chip is molded with the plastic material, the divided output electrodes 8 of the light receiving elements 5 and 6 are simultaneously molded and led out to both ends of the package 7.

The sixth embodiment shown in FIGS. 6 and 7 is an example in which the light receiving elements are optical fibers 61 and 62. By configuring the part for amplifying or calculating the output from the light receiving element by another unit, the size of the light receiving part can be made as small as possible, and the restrictions on the place to mount this device can be reduced.
Reference numeral 63 in the figure is a polarizer that polarizes the light emitted from the LED 3.

In addition, in the configuration of 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 component and the light amount of the S-polarized component, and as the light emitting means used in this case, , LE with almost equal amounts of light emitted from both polarization components
It is preferable to use D. However, as in the case of determining the surface roughness such as the presence or absence of gloss on the surface of the detected object 2, when it is determined whether or not the polarized component is preserved when reflected by the detected object, 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. Further, instead of the semiconductor laser, as in the seventh embodiment shown in FIG.
A configuration may be adopted in which a polarizer 10 that transmits light in one polarization direction is provided for the LED 3 that emits P- and S-polarized light.

In particular, when discriminating a transparent substance such as glass as the object to be detected, it is preferable to determine the incident angle a1 from the light emitting means to the object to be detected as follows. That is, FIG. 9 shows the angular dependence of the reflectance of glass. The vertical axis in FIG. 9 represents the reflectance, and the horizontal axis represents the incident angle a1 of the light from the light emitting means with respect to the detected object, that is, the glass surface. And Rs shows the reflectance of the S polarization component by glass, and Rp has shown the reflectance of the P polarization component similarly.

As shown in FIG. 9, when the incident angle a1 is 50 to 60 degrees, the ratio of the reflectance of the S-polarized component and the reflectance of the P-polarized component, that is, Rs / Rp becomes the largest. As shown in the figure, Rp = 0 when the incident angle a1 of the light from the light emitting means with respect to the glass surface is 56.3 degrees (= aB). This aB
Is generally called the Brewster angle. Therefore, the incident angle a1 of the light from the light emitting means with respect to the glass surface is 40
If the positional relationship between the light emitting element as the light emitting means and the glass surface is set so as to be approximately 65 degrees, it is possible to determine the transparent body (glass body) with high sensitivity.

The eighth embodiment shown in FIG. 10 shows the basic concept of another embodiment of the optical device of the present invention. In the structure shown in FIG. 10, an optical lens 12 is arranged between the light emitting element 3 and the object 2 to be detected, and the collimating means by the optical lens 12 improves the utilization efficiency of the light emitted from the light emitting element 3. It was done. Further, a second optical lens 13 is provided between the detected object 2 and the light receiving means.
Are arranged, and the reflected light is converged by the second optical lens 13. The polarization beam splitter 4 disposed in the convergent path of the reflected light mainly causes S
The polarized light component is received as reflected light by the first light receiving element 5, and the P polarized light component is mainly received as transmitted light by the second light receiving element 6. In the example shown in FIG. 10, since the polarization beam splitter 4 is arranged in the convergent path of the reflected light, it is preferable to use one having a small incident angle dependency.

With this configuration, it is possible to increase the utilization efficiency of reflected light, and it is possible to comprehensively increase the detection sensitivity of the object to be detected.

Next, a ninth embodiment shown in FIG. 11 is shown in FIG.
In the configuration shown in FIG. 3, the light emitted from the light emitting element 3 is radiated to the detected object 2 as gentle divergent light via the first optical lens 12. A second optical lens 13 is arranged between the object 2 to be detected and the light receiving means as in the example of FIG. 10, and the reflected light is converged by the second optical lens 13.

With this structure, the output ratio of the two light receiving elements 5 and 6 does not fluctuate with respect to the position fluctuation or the tilt fluctuation of the object to be detected 2, and a stable detection capability is exhibited.

In FIG. 11, the light emitted from the light emitting element 3 may be radiated to the detected object 2 via the first optical lens 12 as gently convergent light. In this case, as in the case shown in FIG. 10, it is possible to increase the utilization efficiency of the light emitted from the light emitting element 3.

FIG. 12 shows a tenth embodiment of the construction for detecting the surface condition. From LED3, L
The ED light is emitted as polarized light through the polarizer 10. In this case, the LED 3 is used as a semiconductor laser and the polarizer 10 is used.
You may put on. Light in the vicinity of the optical axis of the light slightly diverged and emitted from the LED 3 is made to enter the detected object 2 substantially vertically. Then, the light receiving means is arranged so as to be able to receive the regular reflection light reflected by the detected object 2.

At this time, if the surface of the object 2 to be detected is flat, the polarized component of the light emitted from the LED 3 is stored and reflected, and if the surface is rough, it is diffusely reflected on the surface. For example, when the surface is a rough surface without preserving the polarized light, the light receiving amounts of the two light receiving elements 5 and 6 are substantially the same. Therefore, the surface state of the detected object 2 can be determined.

The eleventh embodiment shown in FIG. 13 includes a plurality of light receiving elements 5 and 6 for individually receiving the reflected light from the detected object 2, the light receiving elements 5 and 6 and the detected object 2. It is composed of analyzers 20 and 21 which are disposed in between and which mainly extract reflected light in different polarization directions from reflected light from the detected object 2.

Each of the analyzers 2 in this example
Reference numerals 0 and 21 are for separating the reflected light from the object 2 to be detected into two polarized lights having a relation orthogonal to each other.
Mainly transmits the S-polarized component, and the analyzer 21 mainly transmits the P-polarized component. Therefore, the detected object 2 can be discriminated based on the ratio of the polarized light components irradiated on the light receiving elements 5 and 6 as in the case of FIG.

In the example of FIG. 13, the analyzers 20 and 21 which mainly transmit the S-polarized component and the P-polarized component are
Although an example is shown in which the light receiving elements 5 and 6 and the object to be detected 2 are arranged, for example, instead of the analyzers 20 and 21, a polarization beam splitter (separating and extracting S polarization component and P polarization component, respectively) (Not shown) may be used. Further, in FIG. 13, the detected object 2 and the analyzer 20 are
, And between the detected object 2 and the analyzer 21, or between the analyzers 20 and 21 and the light receiving elements 5 and 6, respectively, an optical lens that converges the reflected light from the detected object 2 (not shown). It is possible to increase the detection sensitivity of the detected object by arranging (). Also in this case, instead of the analyzers 20 and 21, a polarization beam splitter (not shown) that separates and extracts the S polarization component and the P polarization component may be used.
When the polarization beam splitter is used in this way, the polarization beam splitter is arranged in the converging path of the reflected light, and therefore it is preferable to use the one having a small incident angle dependency.

The twelfth embodiment shown in FIG. 14 is an example using the concept of the eleventh embodiment in the configuration of FIG. 2 and using an optical fiber as a light receiving element.

According to this structure, the fibers are arranged in the moving direction of the object 2 to be detected, so that the moving direction can be detected by detecting the presence or absence of the object (including the transparent body).

As in the eleventh embodiment, the analyzers 20, 2 are
Instead of 1, the polarization beam splitter 4 may be used, or an optical lens may be arranged between the object to be detected 2 and the analyzers 20 and 21, or between the analyzers 20 and 21 and the light receiving elements 5 and 6, respectively. However, it is also possible to increase the detection sensitivity of the detected object 2.

The thirteenth embodiment shown in FIG. 15 shows an example of a surface state detecting device suitable when at least the surface of the object 2 to be detected is made of a transparent or translucent material. In this example, a plurality of light receiving elements for individually receiving the reflected light from the front surface and the back surface of the transparent or semitransparent substance are provided. That is,
When a glass plate is taken as an example of the object to be detected 2, the reflected light from the surface 2a of the glass plate is received by the first polarization beam splitter 4a, and the S-polarized component which is the reflected light of the first polarization beam splitter 4a. Is received by the first element 30a of the first divided light receiving element 30. The P-polarized light component, which is the transmitted light of the first polarization beam splitter 4a, is received by the second element 30b of the first split light-receiving element 30.

Similarly, the reflected light from the back surface 2b of the glass plate is received by the second polarization beam splitter 4b, and the S-polarized component which is the reflected light of the second polarization beam splitter 4b is divided into the second split. Light is received by the first element 31a of the light receiving element 31. The P-polarized light component, which is the transmitted light of the second polarization beam splitter 4b, is received by the second element 31b of the second split light-receiving element 31. Then, the first divided light receiving element 30
It is possible to detect the state of the surface of the glass plate by taking the output ratio of the first element 30a and the second element 30b. Further, by taking the output ratio of the first element 31a and the second element 31b of the second divided light receiving element 31, it is possible to detect the state of the back surface of the glass plate.

With this configuration, it becomes possible to detect the state of the object 2 to be detected, that is, the front and back surfaces of the glass plate, simultaneously and individually. This can detect the degree of fogging on the surface of the glass plate, that is, the inside,
It is possible to simultaneously detect the adhered state of water drops on the back surface of the glass plate, that is, on the outside.

FIG. 16 shows a case in which the presence / absence of the object 2 is detected and the type is discriminated by the ratio of the outputs from the light receiving element 5 receiving the P-polarized component and the light receiving element 6 receiving the S-polarized component as shown in FIG. FIG. 14 is a block diagram of a circuit part of FIG.

FIG. 17 is a block diagram according to the fourteenth embodiment in the case of detecting or discriminating with the signal of the difference / sum of the two polarization components.

When the discrimination is made by the difference signal, the divider is opened to connect the points A and C. When the discrimination is made by the sum signal, the divider is opened and the points B and C are made. It is configured to connect dots.

Reference numerals 71 and 72 shown in FIGS.
Is an amplifier, 73 is a divider, 74 and 75 are subtractors, and 76 is a discriminator.

FIG. 19 shows a characteristic example of the polarization beam splitter according to the 15th embodiment. As shown in FIGS. 10 and 11, when the polarization beam splitter 4 is arranged in the convergent optical path between the lenses 12 and 13 and the light receiving elements 5 and 6, the characteristics of the polarization beam splitter 4 are that it enters the polarization beam splitter. If the reflectance or the transmittance is not substantially constant for light of any incident angle, for example, the P-polarized light component is received by the light receiving element 5 that should receive the S-polarized light component, and the detection accuracy deteriorates.

When no optical lens is used as shown in FIG.
In order to prevent the reflected light from the detected object 2 from entering the one of the light receiving elements 5 and 6 without being transmitted or reflected by the polarization beam splitter 4, the light receiving means has an opening as shown in FIG. It is necessary to provide 81. By providing the opening 81, the light reflected by the detected object 2 and incident on the light receiving means is limited, and the light incident on the polarization beam splitter 4 is also limited to some extent. However, as shown in FIG. Compared with the specularly reflected light shown by the diagonal line, the diffusely reflected light shown in FIG. 6 is incident on the polarization beam splitter 4 in a wider incident angle range. , 6 will be received by the light-receiving element 5 or 6 and should not be detected or discriminated correctly. Therefore, it is a necessary condition that the incident angle dependence of the reflectance or the transmittance of the polarization beam splitter 4 is small as shown in FIG.

As in the sixteenth embodiment shown in FIG. 20, in the case where the lens is not used, as described above, in order to prevent the light reflected by the object 2 to be detected from passing through or reflecting the PBS 4, Alternatively, an opening 81 is provided in order to receive only specularly reflected light as much as possible. In this case,
If the light receiving element 5 that receives the S-polarized light component is located on the detected object 2 side (the side closer to the opening 81), the volume of the entire device can be reduced.

That is, as shown in FIG. 21, it is assumed that the PBS 'splits the light incident at the central incident angle θ ₁ into P-polarized light and S-polarized light. At this time, considering that both the specular reflection light and the diffuse reflection light reflected by the object to be detected 2 are transmitted or reflected by the PBS 4 to be received by the light receiving elements 5 and 6, a,
Although it is necessary to bring the opening or the wall of the housing to the positions b and c, when this is configured as shown in FIG.
a, b, and c are located at d, e, and f, respectively, and the volume of the device is greatly different even if the same element is used. In the case of FIG. 22, the distance from the detected object 2 is increased, so that the light utilization efficiency is also reduced. .

In the configuration shown in FIG. 20, in the case of discriminating between the detected objects 2 (for example, discriminating the kind of paper), the ratio of the P-polarized component and the S-polarized component contained in the reflected light is small, the photodetector In 5 and 6, the opening 81 is provided so as not to receive the diffusely reflected light as much as possible, and the light entering the light receiving elements 5 and 6 is limited.
In consideration of the distance to the device, the size of the opening 81 is the same as in the seventeenth embodiment shown in FIGS. 23A and 23B, and the light reflected by the detected object 2 passes through the opening 81. According to the beam diameter of the regular reflection light at this time, if the portion near the LED 3 is made small and the portion far from the LED 3 is made large, the regular reflection light can be efficiently received.

Here, the solid line is the range of the specular 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 distant position, and the dotted line is the positive range when the detected object 2 approaches. This is the range of the reflection component, and the range of the dotted line in the opening 81 is smaller than the range of the solid line, so the opening 81 is formed accordingly.

The object 2 to be detected has a structure as shown in FIG.
When there is no light, the light emitted from the LED 3 is
It is assumed that the flat or cylindrical background objects 91 and 92 are reflected and are received by the optical device 93 having the light receiving elements 5 and 6 as in the eighteenth embodiment shown in FIGS.

At this time, if the background objects 91 and 92 are made of metal, the polarization directions of the light from the LEDs 3 are stored in the light receiving elements 5 and 6 when the object 2 to be detected does not exist, so that 2 The ratio of the two received light amounts is almost the same. (Because the LED 3 emits randomly polarized light). Therefore, when the paper 94 or the like which is almost diffused and reflected as the detected object 2, the ratio of the two received light amounts becomes substantially the same, and therefore the distinction is lost and another calculation is required.

Therefore, the background pedestals 91 and 92 are shown in FIG.
Choose a dielectric 95 (eg glass) as shown in
As shown in FIG. 26, by applying a paint 97 to the metal 96 to make the reflectances of the P-polarized component and the S-polarized component different, the above-described detection can be performed by the same calculation.

Further, when this apparatus moves on the object 2 to be detected and detects the edge thereof to determine the size, posture, positional deviation, etc. of the object 2 to be detected, in the part where the apparatus is sensing If there is a change in the material or surface state of the backgrounds 91 and 92, accurate edge detection becomes impossible, and even if the detected object 2 is a transparent body, even the detection may become indistinguishable.

Now, a threshold automatic setting procedure will be described as a nineteenth embodiment. When an automatic tuning command is issued or at a predetermined timing (for example, when the power is turned on or for a certain period of time), the threshold value is automatically adjusted or corrected in the following procedure.

In the first procedure, the objects to be detected are sensed by the user in a predetermined order, or the sensing device or a device equipped with the sensing device is sensed in order from the part stocked therein. The optimum threshold value is set based on the output signal of the device. In the second procedure, a limited object to be detected, which is relatively difficult to discriminate, is sensed in the same manner as in the first procedure, and an optimum threshold value is set from the output signal of the device.

The twentieth embodiment shown in FIG. 28 shows an application example of the detection device. In the example shown in FIG. 28, in a printing machine such as a printer or a copier (other word processors, plotters, fax machines, recorders, etc.), is the print target (detected object) 2 stored in the paper tray 2 paper? The example shown is used to detect whether it is an OHP film, that is, whether it is a transparent body or an opaque substance, or to detect the type of paper (plain paper, thermal paper, coated paper).

The detecting device A is arranged above the paper tray, discriminates the object to be printed, and adjusts and sets the mechanical parameters of the conveying path, the printing method, the printing density and the like for the printing process.

In addition, this detecting device
It may be arranged (not shown) in the conveyance path, the object to be printed may be discriminated, and the above-mentioned parameters may be adjusted and set.

FIG. 29 shows an example in which the detection device A of the present invention as the paper discriminating device is attached to the print head B to adjust the parameters of the printing process according to the type of paper to be printed. is there.

Since the printer is attached to the print head B, the size of the paper can be determined by detecting the edge of the paper.
Optimal printing is possible by detecting the posture and position shift.

The twenty-first embodiment shown in FIG. 30 shows another application example of the detection apparatus of the present invention. This Figure 30
In the example shown in FIG.
It is arranged above to detect the degree of fogging of the windshield 41. That is, it is possible to detect the degree of fogging by detecting the presence or absence of gloss on the surface of the windshield 41 on the inside of the vehicle, and when fogging of a predetermined amount or more occurs, the air conditioner is automatically operated. ,
It can be controlled to activate the dehumidification function. In addition to cars, it can also be applied to the detection of fog in windows of homes and buildings, or in mirrors.

Further, as shown in FIG. 31, when the detection device A detects whether or not water droplets are attached to the surface of the windshield 41 (outside the vehicle body), and it is determined that water droplets of a predetermined amount or more are attached. Can be controlled to automatically operate the wind wiper.

It is also possible to detect a change in the intensity of light entering from the outside of the windshield 41 and automatically control the light to be turned on and off with a predetermined illuminance as a threshold value.

Furthermore, a twenty-second embodiment shown in FIG. 32 shows another application example of the detection apparatus of the present invention.
In the example shown in FIG. 32, the detection device A for detecting the surface state of the radiator 51 of the air conditioner outdoor unit 50 is arranged in the immediate vicinity of the radiator 51. That is, whether or not frost is attached to the surface of the radiator 51 is detected, and the operating state of the air conditioner outdoor unit 50 is automatically controlled.

Similarly, it can be applied to control the operating state by detecting frost attached to the radiator of the refrigerator. With the same principle, as a twenty-third embodiment, for example, it is possible to provide a function of notifying the user by detecting the dust attached to the fan, or a function of automatically removing the dust, or cleaning. It is also possible to realize efficient operation by detecting the clogging of the filter inside the machine due to dust and providing a function to notify the user.

As a twenty-fourth embodiment, the foreign matter inspecting apparatus in the manufacturing line has the same principle, that is, the configuration shown in FIG. 11 or 12, the LED 3 emits polarized light, and there is no foreign matter on the object. At this time, the polarized light is preserved and is received by the light receiving elements 5 and 6, but if there is a foreign substance on the object, diffuse reflection is performed there, so that the polarized light is spilled,
The outputs from the light receiving elements 5 and 6 change, and foreign matter can be detected. Based on such a principle, it is possible to improve the function by attaching the detection device to a device used in a semiconductor manufacturing process such as a mask aligner.

In the twenty-fifth embodiment shown in FIG. 33, the detection device A detects the road surface condition to perform the optimum control of the ABS (anti-lock brake system) and the suspension, the hardness of the brake, the steering wheel or the accelerator. , Is an example of adjusting the transmission condition.

This is the reverse principle of the twenty-fourth embodiment. With the structure as shown in FIGS. 1 and 11, polarized light is reflected and reflected on an ordinary road surface, but when the road surface is wet with rain, the polarized light is preserved and reflected. It is detected that the ratio of doing it increases. This makes it possible to realize a safer vehicle (control).

As another application, by attaching this device to the end of the car (around the bottom of the door), the center line is detected, and when the car is running out of the center line due to sleep etc. It has a function to inform people and realizes safe driving.

As a twenty-sixth embodiment utilizing the fact that a transparent body can be detected by the structure shown in FIG. 11, FIG.
As shown in FIG. 5, it is applied to detect the presence or absence of the transparent sheet or the transparent film D in the production line C, or the transparent film packaged in the product.

In the detection device of the present invention, by adopting the structure as shown in FIG. 11, for example, it is possible to determine the type of the dielectric material based on the difference in the refractive index and the surface state. It is possible.

Therefore, as the twenty-seventh embodiment, an application example as a color mark sensor, a color copying machine having a color check function, or an inspection machine of a coating apparatus can be considered.

As a twenty-eighth embodiment to which the inspection apparatus of the present invention is capable of discriminating between paper quality and ink quality, as a twenty-eighth embodiment, it is possible to discriminate bills in a CD, ATM vending machine, etc. Conceivable.

FIG. 36 shows a bill insertion slot F of such an apparatus E.
In this example, the detection device A of the present invention is arranged to perform bill discrimination.

The twenty-ninth embodiment shown in FIG. 37 is an application example as a device for measuring the film thickness of a liquid. In the configuration as shown in FIG. 11, light is emitted from the LED 3 to the rough surface,
When the light receiving elements 5 and 6 are configured to receive specular reflection light and diffuse reflection light, the ratio of receiving specular reflection light and diffuse reflection light changes depending on the film thickness of the liquid G. The film thickness is detected by changing the amount of light received at. This allows offset printing, for example,
It can be used as a device to keep the thickness of the dampening water adhered to a constant level and realize beautiful printing.

[0116]

As described above, according to the optical device of the present invention, the light emitting means for emitting light to the object to be detected and the light from the light emitting means reflected, transmitted or diffused by the object to be detected are provided. The light receiving means is configured to receive the P-polarized component and the S-polarized component, respectively, of the light from the object to be detected separately. The output ratio of the light receiving element for the P and S polarization components does not fluctuate with respect to fluctuations, and stable surface state detection capability is exhibited. Further, since the ratio of the P and S polarized components is detected, even if an object has the same surface roughness as the conventional one, the type of the object to be detected (for example, a transparent body and a metal having a smooth surface) Etc.) can be discriminated, and its detection capability is increased.

Further, according to the optical device of the present invention, as the light emitting means, mainly the P-polarized component or the S-polarized component is selected and projected on the object to be detected.
It is possible to further increase the ability to detect the surface state (smooth surface or rough surface) of the detected object. Furthermore, a transmission type configuration as shown in FIGS. 2 and 3 is also possible, and various detection methods according to the property of the detection object and the environment in which the device is attached are possible.

[Brief description of drawings]

FIG. 1 is a side view showing a basic configuration according to a first embodiment of an optical device of the present invention.

FIG. 2 is a side view showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a side view showing a configuration of a third exemplary embodiment of the present invention.

FIG. 4 is a perspective view of a fourth embodiment showing a specific example of a light receiving element used in the optical device shown in FIGS.

5 is a perspective view of a fifth embodiment showing another specific example of the light receiving element used in the optical device shown in FIGS. 1 to 3. FIG.

FIG. 6 is a side view showing a configuration of a sixth exemplary embodiment of the present invention.

FIG. 7 is a side view showing another configuration of the sixth exemplary embodiment of the present invention.

FIG. 8 is a side view of a seventh embodiment showing another configuration of the light emitting section used in the optical device shown in FIGS.

FIG. 9 is a characteristic diagram showing a reflection characteristic of a transparent material.

FIG. 10 is a side view showing a basic configuration of an eighth embodiment of the present invention.

FIG. 11 is a side view showing a basic configuration of a ninth embodiment of the present invention.

FIG. 12 is a side view showing a basic configuration of a tenth embodiment of the present invention.

FIG. 13 is a side view showing a basic configuration of an eleventh embodiment of the present invention.

FIG. 14 is a side view showing a basic configuration of a twelfth embodiment of the present invention.

FIG. 15 is a side view showing a basic configuration of a thirteenth embodiment of the present invention.

FIG. 16 is a block diagram showing a configuration of a circuit unit according to a fourteenth embodiment of the present invention.

17 is a block diagram showing a configuration of a modified example of the circuit unit shown in FIG.

FIG. 18 is a side view showing the basic configuration of a fifteenth embodiment of the present invention.

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

FIG. 20 is a vertical sectional view showing a specific configuration of the sixteenth embodiment of the present invention.

FIG. 21 is an optical path diagram of a seventeenth example showing an example of the optical path in the configuration shown in FIG.

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

FIG. 23 is an explanatory diagram showing the shape of the opening shown in FIG. 20.

FIG. 24 is a perspective view showing an arrangement according to an eighteenth embodiment of an example of a background object provided in the optical device of the present invention.

FIG. 25 is a perspective view showing the arrangement of another example of the background object provided in the optical device of the present invention.

FIG. 26 is a side view showing an example of an improved configuration of the background object shown in FIG. 24.

27 is a perspective view showing another example of the improved configuration of the background object shown in FIG. 24. FIG.

FIG. 28 is a perspective view showing an application example of a twentieth embodiment of the optical device of the present invention.

FIG. 29 is a perspective view showing another application example of the twentieth embodiment of the optical device of the present invention.

FIG. 30 is a perspective view showing an application example of the optical device according to the 21st embodiment of the present invention.

FIG. 31 is a side view showing another application example of the twenty-first embodiment of the optical device of the present invention.

FIG. 32 is a perspective view showing an application example of the optical device according to the 22nd embodiment of the present invention.

FIG. 33 is a perspective view showing an application example of the optical device according to the twenty-fifth embodiment of the present invention.

FIG. 34 is a perspective view showing an application example of the optical apparatus according to the 26th embodiment of the present invention.

FIG. 35 is a perspective view showing another application example of the twenty-sixth embodiment of the optical device of the present invention.

FIG. 36 is a perspective view showing an application example of the optical device according to the 28th embodiment of the present invention.

FIG. 37 is a side view showing an application example of the optical device according to the 29th embodiment of the present invention.

FIG. 38 is a basic conceptual diagram showing the configuration of an example of a conventional optical device.

[Explanation of symbols]

 1 Case 2 Object to be detected 3 Light emitting element (light emitting means) 4 Polarization beam splitter 5 Light receiving element (light receiving means) 6 Light receiving element (light receiving means) 7 Package 8 Output electrode 10 Polarizer 12 Optical lens 13 Optical lens 20 Analyzer 21 Analyzer 61,62 Optical fiber 81 Opening 91,92 Background object

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hironobu Kiyomoto 10 Odoron-cho, Hanazono Doudocho, Ukyo-ku, Kyoto-shi, Kyoto

Claims (39)

[Claims] 1. A light emitting means for emitting light to a detected object, and a light receiving means for receiving any light from the light emitting means reflected, transmitted through the detected object, or partially scattered by the detected object. In the optical device for detecting the type of an object or detecting the presence or absence of the object, the light receiving unit separates a plurality of polarization components from the light from the object to be detected or the light partially scattered by the object to be detected. An optical device characterized by receiving light into. 2. The light receiving means is mainly a P-polarized light component and mainly S-polarized light, out of the reflected light from the object to be detected, the transmitted light or the light partially scattered by the object to be detected.
The optical device according to claim 1, wherein the polarized component and the polarized component are individually received. 3. The light receiving element, wherein the light receiving means mainly receives a P-polarized light component of the reflected light from the detected object, the transmitted light, or the light partially scattered by the detected object. 3. The optical device according to claim 1, further comprising a plurality of light receiving elements including a light receiving element that mainly receives the S-polarized component. 4. The optical device according to claim 1, wherein the light receiving unit has a plurality of light receiving elements arranged in one package. 5. The optical device according to claim 1, wherein the light receiving unit is formed by dividing one chip into a plurality of light receiving elements. 6. The optical device according to claim 1, wherein the light receiving element is an optical fiber. 7. The optical device according to claim 1, wherein the light emitted from the light emitting means is configured to enter the surface of the object to be detected in an oblique direction. apparatus. 8. The optical device according to claim 7, wherein the incident angle of the light emitted from the light emitting means with respect to the detected object is 50 degrees or more. 9. The optical device according to claim 7, wherein the incident angle of the light emitted from the light emitting means with respect to the detected object is in the vicinity of the Brewster angle. 10. The light emitted from the light emitting means in the vicinity of the optical axis is emitted substantially perpendicularly to the surface of the object to be detected. The optical device according to item 1. 11. The light emitting means and the light receiving means are provided in different housings, and when the detected object is not present, the light from the light emitting means is directly received by the light receiving means. The optical device according to any one of claims 1 to 6 or 10. 12. The light from the light emitting means is obliquely incident on the surface of the detected object, and the light receiving means receives the light transmitted through the detected object. The optical device according to. 13. The optical device according to claim 1, wherein the light receiving unit is arranged at a position for receiving a regular reflection component from the detected object. 14. The light emitting means according to claim 1, wherein the light intensity of the P-polarized component and the light intensity of the S-polarized component emitted to the object to be detected are substantially equal to each other. The optical device described. 15. The light emitting means according to claim 1, wherein the light emitted to the object to be detected is mainly P-polarized component or mainly S-polarized component. Optical device. 16. The light emitting means comprises a light emitting element and a polarizer for extracting mainly a P polarized component or an S polarized component of light emitted from the light emitting element. The optical device according to any one of claims 1 to 15. 17. The optical device according to claim 1, wherein the light emitted from the light emitting unit is applied to the detected object through a collimating unit including an optical lens. 18. The light emitted from the light emitting means is applied to the detected object as gentle divergent light or convergent light via the optical lens. The optical device described. 19. The light receiving means, and a plurality of light receiving elements for separately receiving any one of reflected light from the detected object, transmitted light, and light partially scattered by the detected object; It is arranged between an element and the detected object, and is composed of an analyzer that mainly extracts light of different polarization directions from the light from the detected object or the light partially scattered by the detected object. The optical device according to any one of claims 1 to 18, characterized in that: 20. A plurality of light receiving elements, wherein the light receiving means separately receives any of reflected light from the detected object, transmitted light, or light partially scattered by the detected object; The light, which is disposed between the element and the object to be detected, is either the reflected light from the object to be detected, the transmitted light, or the light partially scattered by the object to be detected, is mainly a P-polarized component and a light. The optical device according to any one of claims 1 to 18, wherein the optical device is composed of a polarization beam splitter that separates the S polarization component into an S polarization component. 21. A plurality of light receiving elements, wherein the light receiving unit separately receives any one of reflected light from the detected object, transmitted light, and light partially scattered by the detected object; The light, which is disposed between the element and the object to be detected, is either the reflected light from the object to be detected, the transmitted light, or the light partially scattered by the object to be detected, is mainly a P-polarized component and And a polarization beam splitter that separates the S polarization component into the S polarization component and between the polarization beam splitter and the object to be detected, and reflected light from the object to be detected, transmitted light, or partially scattered by the object to be detected. 3. An optical lens for converging light, which is characterized in that
0. The optical device according to any one of 0. 22. The optical device according to claim 20, wherein the polarization beam splitter has a small incident angle dependence of reflectance in a desired incident angle range. 23. The polarization beam splitter is characterized in that a dielectric multilayer film including a dielectric or a metal film is formed on a surface of a parallel plate.
The optical device according to claim 1. 24. The optical device according to claim 20, wherein the center value of the incident angle range of light on the polarization beam splitter is in the vicinity of the Brewster angle. 25. The polarization beam splitter reflects an S-polarized component, and the light-receiving element that receives the S-polarized component is located closer to the object to be detected than the light-receiving element that receives the P-polarized component. Item 25. The optical device according to any one of Items 20 to 24. 26. The light receiving means separately receives reflected light from the front surface and the back surface of the transparent or semitransparent substance, respectively, when at least the surface of the detected object is made of a transparent or semitransparent substance. The optical device according to any one of claims 1 to 9 or 13 to 25, characterized in that the optical device comprises a plurality of light receiving elements. 27. Non-parallel light is incident on the light receiving means,
27. The light receiving means comprises an opening, and the size of the opening is small in a portion close to the light emitting means and large in a portion far from the light emitting means. Optical device. 28. When the object to be detected does not exist, the light receiving means receives the reflected light from the light emitting element that reflects the background object, and the surface of the background object is made of a material containing at least a dielectric. Claims 1 to 10, characterized in that
Alternatively, the optical device according to any one of 13 to 27. 29. When the object to be detected does not exist, the light receiving unit receives the reflected light from the light emitting element that reflects the background object, and the background object is at least a portion where the light emitted from the light emitting unit is applied. 29. The optical device according to any one of claims 1 to 10 or 13 to 28, wherein is an uniform shape or a uniform material. 30. The optical device is provided with a predetermined timing,
30. The threshold value for determination is automatically set or automatically corrected by sensing a part or all of several types of detected objects to be determined when a command is issued. The optical device. 31. The optical device determines the presence or absence of a detected object or the type of the detected object based on any of the ratio, sum, difference, difference / sum of the amounts of light of different polarization components received by the plurality of light receiving elements. The optical device according to any one of claims 1 to 30, wherein: 32. The optical device according to claim 1, wherein it is determined whether or not the detected object is a transparent body. 33. The optical device according to claim 1, wherein the detected object is paper or film, and at least the type thereof is discriminated. 34. The optical device according to claim 1, wherein the presence or absence of gloss on the surface of the detected object is determined. 35. The method according to claim 1, wherein it is determined whether or not foreign matter is attached to the surface of the detected object, or whether or not foreign matter is attached to the background object. The optical device according to claim 1. 36. The optical device according to claim 1, wherein it is determined whether or not the surface of the detected object is cloudy. 37. The method according to claim 1, wherein it is determined whether water droplets are attached to the detected object or whether frost is attached to the background object.
31. The optical device according to any one of 1 to 31. 38. The method according to claim 1, wherein it is determined whether frost is attached to the detected object or whether water droplets are attached to the background object. The optical device according to. 39. The optical device according to claim 1, wherein the detected object is a suspended matter or particles in the air.