JPH06102351A - Photoelectric detector - Google Patents

Abstract

PURPOSE:To provide a photoelectric detector using a reflection photo interrupter which has extremely less influence on the reflection factor of a detectee and has a high ratio of S/N to allow high-precision positional detection of the detectee by injecting projected light passed through an appropriate detected light passage, as only part of projected light from the projection area of the reflection photo interrupter, to the receiving area. CONSTITUTION:A photoelectric detector consists of a reflection member 5 which is opposed to a reflection interrupter 1 in its field of view to form a detected light passage L through which projected light from a projection area 2 is injected to a receiving area in association and a light passage restricting means 7 which is arranged in a space between the projection area 2 and the receiving area 3 to be extended from the projection plane 2a and the receiving plane 3a to the view side to prevent the injection of the projected light from others than the detected light passage L to the receiving area 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric detection device for detecting the position of an object to be detected by using a reflection type photo interrupter.

[0002]

2. Description of the Related Art Hitherto, various photoelectric detection devices for detecting the position of an object to be detected by using a reflection type photo interrupter have been proposed or put into practical use.
For example, it is extremely common to have a structure as shown in the schematic sectional view of FIG.

In FIG. 4, a reflection type photo interrupter 1 is provided with a light projecting portion 2 made of, for example, a light emitting diode and a light receiving portion 3 made of, for example, a phototransistor, and is supported by a mounting member 4. The light projecting unit 2 and the light receiving unit 3 share the field of view and are arranged in parallel.

The reflecting member 5 is arranged so as to face the reflective photo interrupter 1 in the visual field.

That is, when nothing is present between the reflecting member 5 and the reflection type photo interrupter 1, the reflecting surface 5a reflects the light projected from the light projecting surface 2a of the light projecting section 2. It is arranged so as to be guided to the light receiving surface 3a of the light receiving section 3. In other words, the reflection member 5 cooperates with the reflection type photo interrupter 1 to form the detection optical path L shown by the one-dot chain line in the figure.

The object 6 to be detected is a reflection type photo interrupter 1.
And the reflecting member 5, and moves in the direction of arrow A, for example. Further, the detection object 6 is formed with translucent slits 6a and 6b through which light can pass.

The operation of detecting the position of the object 6 to be detected in the photoelectric detection device constructed as described above will be briefly described below.

First, assuming that the initial state is the state shown in FIG. 4, that is, a part of the object 6 to be detected crosses the entire detection optical path L, in this initial state, the light projected from the light projecting section 2 is projected. Is blocked by the object 6 to be detected, and therefore, if the reflectance of the object 6 is set to be small, it can be considered that the light projection does not reach the light receiving portion 3.

On the other hand, the object 6 moves in the direction of arrow A,
When the light transmitting slit 6a or 6b reaches the detection light path L, the light projected from the light projecting section 2 passes through the light transmitting slit 6a or 6b and is reflected by the reflecting surface 5a of the reflecting member 5,
The light receiving portion 3 passes through the light transmitting slit 6a or 6b again.
Will be incident on.

The light receiving section 3 is composed of, for example, a phototransistor, and in such a case, incidence of light projection on the light receiving section 3 is detected as an electrical output that is an ON operation of the phototransistor.

Therefore, the transparent slit 6a or 6
If the size of b is set in consideration of the position to be detected by the detected object 6, the detection optical path L, that is, the light projected from the light projecting unit 2 is reflected when the detected object 6 is at the position to be detected. The optical path that is reflected by the member 5 and reaches the light receiving unit 3 is not blocked. Therefore, the output of the light receiving unit 3 can detect when the detected body 6 is at the position to be detected by the above setting.

In other words, when the body 6 to be detected starts moving, the detection optical path L is formed by the light transmitting slits 6a, 6 of the body 6 to be detected.
b is opened and closed, and the translucent slits 6a and 6b are connected to the detection optical path L.
The detection optical path L is formed every time when the light beam passes through. For this reason, light is projected into the light receiving unit 3 in a pulsed manner, and the light receiving unit 3 generates a pulse output each time the translucent slits 6a and 6b pass through the detection optical path L, whereby the object to be detected is detected. It is possible to detect when 6 is at the position to be detected.

Needless to say, two or more light-transmitting slits 6a and 6b may be provided in the illustrated example depending on the number of pieces of position information to be detected by the object 6.

[0014]

The general example of the photoelectric detecting device using the reflection type photo interrupter has been described above. Is based on the difference in reflectance between the reflection surface of the reflection member and the surface of the detection target that blocks the detection optical path.

That is, it is assumed that an object having a reflectance of 0% is not usually present. Therefore, considering the diffusion and scattering of the light projected from the light projecting section or the distance to the object and the reflectance, the reflectance is small. Even when the detected object is set and the detection optical path is blocked as shown in FIG. 4, the light incident on the light receiving portion is present. Actually, based on the difference between the output level of the light receiving part by the incident light in such a state and the output level of the light receiving part when the light is projected through the light-transmitting slit, the detected object as described above is detected. The position detection operation is being performed.

However, as is well known, the light intensity is inversely proportional to the square of the distance. Therefore, even if there is a large difference in the reflectance between the object to be detected and the reflecting member, the S / N ratio of the photoelectric detecting device will be examined. However, there is a disadvantage that a desired detection operation cannot be expected if the positional relationship among the reflective photo interrupter, the reflecting member, and the detected object is slightly different from the set positional relationship.

That is, the degree of freedom in the arrangement of the reflection type photo interrupter, the reflection member and the like is extremely small, and as a result, the position detection accuracy of the photoelectric detection device cannot be made highly accurate.

Further, the above-mentioned inconvenience has a greater influence in the case of development with a plurality of objects to be detected, and in order to put it into practical use, it is necessary to pay more attention to the arrangement accuracy of the reflection type photo interrupter, the reflection member and the like. Had some inconveniences.

The present invention has been made in consideration of the above points, and has a high S / N ratio, and thus a photoelectric detection device using a reflection type photo interrupter capable of highly accurately detecting the position of the object to be detected. The purpose is to provide.

[0020]

A photoelectric detection device according to the present invention comprises a reflection type photo interrupter, a reflection member, and an optical path restricting means, and the reflection type photo interrupters are arranged side by side so as to share a field of view. It is composed of a light section and a light receiving section, and detects whether the light projected from the light projecting section is reflected by an object in the field of view and received by the light receiving section. Placed opposite each other in the field of view,
It cooperates with a reflective photointerrupter to form a detection optical path in its field of view that causes the light emitted from the light projecting section to enter the light receiving section, and the optical path regulation means is provided between the light projecting section and the light receiving section. Are arranged in the space of each of the light projecting surface and the light receiving surface so as to extend to the field of view side, and prevent the incident light from entering the light receiving section from other than the detection optical path. It is configured to be positioned between the interrupter and the reflecting member via an optical path restricting means, and to block the detection optical path so as to detect the object to be detected.

[0021]

Since the photoelectric detection device according to the present invention is configured as described above, the light projected from the light projecting portion is reflected by the reflecting member, that is, detected, when the object to be detected is not in the detection optical path. It reaches the light receiving portion through the inside of the optical path.

Further, when the object to be detected is present in the detection optical path, the light projected from the light projecting portion does not reach the reflecting member, that is, the detection optical path is blocked and does not reach the light receiving portion.

At this time, the reflectance of the object to be detected is 0%.
Considering that the light is not diffused and the light is diffused and scattered, light that is reflected by the object to be detected and is about to enter the light receiving portion is generated, but such light does not form a detection light path,
Therefore, the light receiving portion is hardly controlled by the control and regulation by the optical path regulating means.

That is, according to the photoelectric detection device of the present invention, even if the reflectance of the object to be detected is high to some extent, unnecessary light reaching the light receiving portion when the detection optical path is blocked is controlled and restricted by the optical path restricting means. Therefore, it is possible to reliably detect the time when the detection optical path is blocked.

To put it more drastically, the photoelectric detection device according to the present invention is based on the difference in reflectance between the reflection surface of the reflection member and the surface of the detection object that blocks the detection optical path in the light reception detection operation by the conventional light receiving section. In contrast to this, the light receiving detection operation by the light receiving unit can be performed regardless of the difference in reflectance between the detected object and the reflecting member.

Therefore, the S / N ratio of the photoelectric detection device can be increased, and therefore the degree of freedom in arrangement of the reflection type photo interrupter, the reflection member, etc. can be greatly increased.
Further, the position detection accuracy of the photoelectric detection device can be made highly accurate.

[0027]

1 is a schematic sectional view showing an embodiment of a photoelectric detection device according to the present invention. In the figure, elements having the same reference numerals as those in FIG. 4 have the same function.

In FIG. 1, 7 is a light projecting section 2 and a light receiving section 3.
In the space X between the light emitting surface 2a and the light receiving surface 3
The present embodiment shows an optical path restricting means which is disposed so as to extend from a toward the visual field side, that is, downward in FIG. 1, and which prevents the projection of light from the light projecting section 2 from entering the light receiving section 3 from other than the detection optical path L. In, the light-shielding wall is integrally formed with the mounting member 4.

The position detecting operation of the detected object 6 in the photoelectric detecting device according to the present invention will be described below. However, only the optical path restricting means 7 is different from the configuration of the conventional example shown in FIG. Performs the same operation as the above-mentioned conventional example.

First, in the state shown in FIG. 1 in which a part of the object to be detected 6 crosses the entire detection optical path L, the light projecting section 2
Since the light emitted from the object 6 is blocked by the object 6 to be detected and the detection optical path L via the reflecting member 5 is not formed, if the reflectance of the object 6 is set to be small as in the prior art example, the above-mentioned light is emitted. Can be regarded as not reaching the light receiving unit 3.

However, as described above, considering that the reflectance of the object to be detected is not 0% and the diffusion and scattering of the projected light are considered, it is unnecessary to reflect the object to be detected 6 and to enter the light receiving portion. Light is generated.

However, in the photoelectric detection device according to the present invention, only the light passing through the detection optical path L formed by the cooperation of the reflection type photo interrupter 1 and the reflection member 5 is received by the light receiving portion 3.
Is provided with an optical path restricting means 7 for controlling the light projection from the light projecting section 2 so as to be incident on the light receiving section 3, in other words, controlling so that light passing through other than the detection optical path L does not enter the light receiving section 3. It is needless to say that the light does not form the detection optical path L. As a result, the unnecessary light is controlled and regulated by the optical path regulating means 7, and specifically, the optical path regulating means 7 is also directed toward the light receiving section 3. Therefore, the light receiving unit 3 can hardly be reached.

That is, the photoelectric conversion device according to the present invention is
Since the optical path restricting means 7 can control and restrict the arrival of unnecessary light to the light receiving portion when the detection optical path L is blocked, the time when the detection optical path L is blocked can be detected with an extremely high S / N ratio. In other words, it is possible to reliably detect the interruption of the detection optical path L without being greatly affected by the reflectance of the detected body 6.

On the other hand, the object 6 moves in the direction of arrow A,
When the light-transmitting slit 6a or 6b reaches the detection light path L, the light projected from the light-projecting portion 2 passes through the light-transmitting slit 6a or 6b and is reflected by the reflecting surface 5a of the reflecting member 5 as in the conventional example. , Passes through the light-transmitting slit 6a or 6b again and enters the light-receiving unit 3.

Therefore, as in the prior art example, the incidence of the projected light on the light receiving portion 3 is detected as an electrical output, and the size of the light transmitting slit 6a or 6b is taken into consideration in the position to be detected by the object 6 to be detected. If set, the time when the detected body 6 is at the position to be detected can be detected by the output of the light receiving unit 3.

In other words, when the body 6 to be detected starts moving, the detection optical path L is formed by the light-transmitting slits 6a, 6a of the body 6 to be detected.
It is opened and closed by b. Therefore, the light receiving part 3 is provided with the light transmitting slit 6
Each time a and 6b pass through the detection optical path L, a pulse output is generated, which makes it possible to detect when the detected body 6 is at the position to be detected.

The light-transmitting slits 6a and 6b are 2 depending on the number of pieces of position information to be detected by the object 6 as in the case of the conventional example.
It is needless to say that more than one piece may be provided, and the optical path restricting means 7 provided integrally with the mounting member 4 may have an independent structure if necessary, or may be integrated with the reflection type photo interrupter 1. Alternatively, it goes without saying that they may be formed non-integrally.

FIG. 2 is a schematic cross-sectional view showing another embodiment of the photoelectric detection device according to the present invention. In the figure, elements having the same reference numerals as those in FIG. 1 have the same function.

As is apparent from FIG. 2, this embodiment is an example in which the optical path regulating means 7 in the previous embodiment is further integrated with the mounting member 4.

The optical path restricting means 7 in this embodiment is constructed by utilizing the thickness of the mounting member 4.

That is, in the previous embodiment, the optical path regulating means 7
In consideration of the regulation area of the detection optical path L, the mounting member 4 is integrally formed as a special light shielding wall, but in the present embodiment, the mounting member 4 having a thickness in consideration of the regulation area in advance.
Is selected, and the insertion holes 4a and 4b to be the optical path are formed.

Therefore, it can be considered that the manufacturing of the mounting member 4 including the optical path restricting means 7 is more advantageous than the previous embodiment in terms of cost and strength.

The detection operation of the object 6 and its S
With respect to the / N ratio, the same action and effect as those of the above-described embodiment can be obtained, and the description thereof will be omitted.

FIG. 3 is a schematic sectional view showing still another embodiment of the photoelectric detection device according to the present invention. In the figure, the elements having the same reference numerals as those in FIGS. 1 and 2 have the same functions.

This embodiment is effective when there are, for example, two objects to be detected, and as is apparent from FIG. 3, unlike the previous embodiment, it has an appropriate opening 8a, and the optical path is restricted. The diaphragm member 8 is arranged between the means 7 and the reflecting member 5.

Therefore, the detection optical path La for causing the light projected from the light projecting section 2 to enter the light receiving section 3 in the present embodiment has the reflection type photo interrupter 1, the reflecting member 5 and the diaphragm member 8.
Are formed by cooperating with each other. That is, in the detection optical path La, the reflecting member 5 reflects the light projected from the light projecting unit 2 supplied through the opening 8 a of the diaphragm member 8 and again enters the light receiving unit 3 through the opening 8 a of the diaphragm member 8. It will be an optical path.

Further, the first object 6A is the optical path regulating means 7
And the diaphragm member 8 between the second detection object 6B and the diaphragm member 8
And the reflection member 5.

Hereinafter, this point will be described in detail. In the case of this embodiment, since a plurality of objects to be detected are to be detected, looking at the relationship between the optical path restricting means 7 and the objects to be detected, the relationship between the first object 6A and the optical path restricting means 7 is Although the same as the previous two embodiments, the relationship between the second detected object 6B and the optical path restricting means 7 is different from the previous two embodiments.

That is, since there are a plurality of objects to be detected, the second object 6B is inevitably arranged at a position away from the optical path regulating means 7.

Therefore, the control and regulation of unnecessary light when the first detection object 6A interrupts the detection light path La is the same as in the previous two embodiments, but the second detection object 6B detects the detection light path La. It is conceivable that the unnecessary light is controlled and regulated at the time of blocking, because the distance from the optical path restricting unit 7 is increased, the blocking of unnecessary light becomes insufficient.

However, in this embodiment, the diaphragm member 8 having an appropriate opening 8a is arranged between the optical path restricting means 7 and the reflecting member 5, and the second object 6B is arranged between the diaphragm member 8 and the reflecting member. It is configured so that it is located between the five.

For this reason, the optical path restricting means 7 is moved from the diaphragm member 8.
The light existing on the side cannot reach the second detection object 6B or the reflecting member 5 unless it passes through the opening 8a, and the light existing on the reflecting member 5 side of the diaphragm member 8 passes through the opening 8a. Unless it passes through, the light cannot be incident on the light receiving unit 3.

Therefore, the generation of unnecessary light and the incidence on the light receiving section 3 when the detection optical path La is blocked by the second object 6B are generated and incident through the action of the diaphragm member 8 described above. By setting the shape of the opening 8a of the diaphragm member 8 in consideration of the formation of the detection optical path La, the generation of the unnecessary light, and the state of incidence on the light receiving portion 3, the optical path restricting means is separated from the optical path restricting means 7. Therefore, the inconvenience that the unnecessary light is blocked by 7 can be improved to a practical level.

As a result, the detection operation of the first and second detection objects 6A and 6B in this embodiment is the basic operation, that is, the operation of detecting whether or not the detection optical path La is interrupted is the same as the above-mentioned two. The operation is similar to that of the embodiment, and S
As for the / N ratio, a sufficiently high S / N ratio can be obtained as in the above-described two embodiments.

In this embodiment also, the translucent slit 6 is used.
The number of a and 6b to be formed and the form of the optical path restricting means 7 can be variously developed as in the conventional example.

[0056]

As described above, the photoelectric detection device according to the present invention allows the light projecting section to allow only the light passing through the detection optical path formed by the cooperation of the reflection type photo interrupter and the reflecting member to enter the light receiving section. Since it is configured to include an optical path restricting unit that restricts the projection of light from, the arrival of unnecessary light at the time of blocking the detection optical path L to the light receiving unit can be controlled and restricted significantly, and as a result, the detection optical path is blocked. It has an effect that time can be detected with an extremely high S / N ratio.

In other words, it is possible to reliably detect the interruption of the detection optical path without being greatly affected by the reflectance of the object to be detected, and the degree of freedom in arranging the reflection type photo interrupter, the reflection member, etc. is relatively high. As a result, the position detection accuracy of the photoelectric detection device can be made extremely high.

Further, since the diaphragm member having an appropriate opening is arranged between the optical path restricting means and the reflecting member, and the object to be detected is positioned between the diaphragm member and the reflecting member, the object to be detected is located. Even in the case of the development of a plurality of devices, it is possible to detect a plurality of objects to be detected with an extremely high S / N ratio, and therefore the position detection accuracy of the photoelectric detection device can be made extremely high.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a photoelectric detection device according to the present invention.

FIG. 2 is a schematic cross-sectional view showing another embodiment of the photoelectric detection device according to the present invention.

FIG. 3 is a schematic sectional view showing still another embodiment of the photoelectric detection device according to the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of a conventional photoelectric detection device.

[Explanation of symbols]

 1 Reflective Photointerrupter 2 Light Emitting Unit 3 Light Receiving Unit 4 Mounting Member 5 Reflecting Member 6 Detected Object 7 Optical Path Restricting Means 8 Aperture Member

Claims (3)

[Claims] 1. A reflection type photo interrupter, a reflection member, and an optical path regulating means, wherein the reflection type photo interrupter comprises a light projecting portion and a light receiving portion which are arranged in parallel so as to share a field of view. Is to detect whether or not the light emitted from the object is reflected by an object in the field of view and received by the light receiving unit, and the reflecting member is arranged to face the reflective photointerrupter and the field of view of the reflective photointerrupter. The optical path regulating means cooperates to form a detection optical path in the field of view for causing the light emitted from the light projecting section to enter the light receiving section, and the optical path restricting means is provided between the light projecting section and the light receiving section. It is placed in the space from the light-projecting surface and the light-receiving surface to the field of view side to prevent the light from entering the light-receiving part from other than the detection optical path of the light projection. To the detected light A photoelectric detector for detecting operation of the object to be detected by blocking the. 2. The photoelectric detection device according to claim 1, wherein the optical path restricting means is a restricting wall formed on the mounting portion for mounting the reflective photo interrupter by utilizing the thickness of the mounting member. 3. A reflection type photo interrupter, a reflection member, an optical path restricting means, and a diaphragm member, and the reflection type photo interrupter comprises a light emitting section and a light receiving section which are arranged in parallel so as to share a field of view. , Is for detecting whether the light projected from the light projecting part is reflected by an object in the field of view and received by the light receiving part, and the reflecting member is arranged opposite to the reflective photo interrupter in the field of view, and the optical path The regulating means is arranged in the space between the light projecting portion and the light receiving portion, and extends from the respective light projecting surface and the light receiving surface toward the field of view, and the diaphragm member is disposed between the optical path regulating means and the reflecting member. The reflecting member, the reflection-type photo interrupter, and the diaphragm member cooperate with each other to form a detection optical path that reflects the light projected from the light projecting unit supplied through the diaphragm member and makes it enter the light receiving unit through the diaphragm member. The optical path control means is formed below the detection optical path of the light projection. Prevents from entering the light receiving portion from the first detected body between the diaphragm member and the optical path control means,
A photoelectric detection device that performs a detection operation of the first and second detection objects by arranging the second detection object between the diaphragm member and the reflection member and blocking the detection optical paths respectively.