JPS6362123A - Object discriminator by light reflection - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device for recognizing an object based on light reflected from the object. In particular, this type of device that recognizes objects based on reflected light from objects can identify objects that are transported on an object transport path or the like.

[Prior Art] A conventional device of this kind for recognizing an object using reflected light from the object has a light source and a photoelectric switch, and an optical system of the photoelectric switch, for example, when discriminating between two types of objects. The focal length of the object was determined, and two types of objects were distinguished based on the size of the output of the photoelectric switch at that time.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional device that recognizes an object using reflected light from the object, the detection element of the optical system of the photoelectric switch varies depending on the focal length. The distance to the detection element must be set with high precision, and the positioning groove is expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The purpose is to provide a discrimination device.

[Means for Solving the Problems] An object discrimination device based on light reflection according to the present invention includes: a light source that illuminates an object to be discriminated; a photo-electric detection means comprising an optical system means and a light receiving element; and a relative distance changing means for changing the distance between the photo-electric detecting means, and an output determining means for determining the output state of the photo-electric detecting means.

[Function] In the present invention, the object to be determined is illuminated by a light source, the brightness of the illuminated object to be determined is measured by a photo-electric detection means consisting of an optical system means and a light receiving element, and furthermore, a relative distance changing means is used. Then, the distance between the object to be determined and the photo-electric detection means is changed, and the output state of the reflected light from the object to be determined by the photo-electric detection means is observed.

The object to be determined can be identified by determining when the output of the photo-electrical detection means is above or below a predetermined output state.

[Example] Fig. 1 is a sectional view showing a groove path of an object discriminating device by light reflection according to an embodiment of the present invention, and Fig. 2 is a cross-sectional view showing a groove path of an object discriminating device by light reflection according to an embodiment of the present invention. An explanatory diagram showing the state of use when installed in a route, FIG. 3 is a circuit diagram of the object discrimination circuit based on light reflection of the embodiment shown in FIG. 2, and FIG. 4 is a circuit diagram of the embodiment shown in FIG. 3. FIG. 5 is a timing chart of control by the object discrimination circuit based on light reflection, and FIG. 5 is an output characteristic diagram of the photo-electric detection means.

In FIG. 2, a main roller conveyor 11 consisting of a plurality of rollers 13 transports an object 10 from left to right in FIG. Note that the object 10 is an object to be discriminated from the perspective of an object discriminating device based on light reflection, and therefore will be described below as an object to be discriminated 10. A sub-roller conveyor 12 consisting of a plurality of rollers 14 selects from the main roller conveyor 11 only those objects 10 having low reflectance and transports them from left to right in FIG. 2. The emitter ST and the light receiver SR constitute a light-responsive switch, and the tip of the object to be determined 10 is placed at a predetermined position, that is, the position where the course of the object to be determined 10 with low reflectance is changed.
This is to detect the arrival of 0. The hydraulic cylinder SL consists of a cylinder part CY and a piston rod PS,
A head portion HD is attached to the opposite side of the cylinder portion CY of the piston rod PS, and constitutes a relative distance changing means for changing the distance between the object to be discriminated 10 and the photo-electric detection means to be described later. There is. Then, the object to be determined 10
When the reflectance of It slides on the common roller 15 of the conveyor 12.

Further, the head portion HD attached to the opposite side of the cylinder portion CY of the piston rod PS has the structure shown in FIG. 1, and has the circuit configuration shown in FIG. .

In FIG. 1, a light-emitting element LED such as a light-emitting diode is attached to the main body housing MH of the head HD, and the light emitted from the light-emitting element LED is illuminated by a projection lens LT as approximately parallel or convergent light rays. The light is projected onto the discrimination object 10.

The filter FT selects the wavelength of the light projected at this time. These light emitting elements LED and light projection lens LT
, or the light emitting element LED, the projection lens LT, and the filter FT constitute a light source unit that illuminates the object to be determined 10.

Further, the reflected light projected from the light source means and reflected by the object to be determined 10 is transmitted through the filter FR and the light receiving lens L.
The light is received by a light receiving element PH such as a phototransistor via R. The filter FR and the light receiving lens LR are
It has the same function as the light source means. The filter FR and the light receiving lens LR constitute an optical system means.

Further, the optical system means and the light receiving element constitute photo-electric detection means.

The light source means, optical system means and photo-electric detection means are
It is built into the main body housing MH of the head HD,
Further, its input/output is similarly incorporated into a built-in circuit board CA, and electrical and mechanical connections with the outside are made through a connector CO.

In FIG. 3, the light emitting element LED is connected in series with a current limiting resistor R1, and the output voltage Vc of a constant voltage circuit (not shown) is
It emits light upon receiving c. The light receiving element PH is connected to the object to be determined 1.
0, it is detected as a change in the voltage drop across resistor R2, and the voltage drop across resistor R2 is detected by the inverting amplifier AM
It is input to the comparator COMP via P. Further, one terminal of the comparator COMP is connected to a threshold voltage setting potentiometer PM connected in series with a resistor R3.
The threshold voltage yth, which is the voltage at the connection point between the two terminals, is input. Then, the output of the comparator COMP is inputted via an OR gate to a retrigger type monostable multivibrator RMM which outputs monostable output in a retrigger type. The output of the retrigger type monostable multivibrator RMM is connected to a hydraulic switching valve VL that controls opening and closing of the hydraulic cylinder SL via a valve drive circuit VD. Note that a pull-up resistor R4 is connected to the output of the comparator COMP. In addition, the OR gate OR triggers the monostable multivibrator MM by the output of the light receiver SR constituting the photoresponsive switch when the tip of the object to be determined 10 is detected, and the monostable multivibrator MM obtained thereby The output of MM is input.

The object discrimination device based on light reflection according to the embodiment of the present invention configured as described above operates as follows.

The object to be determined 10 is being transported by the main roller conveyor 11 from left to right in FIG. At this time, the tip of the object to be determined 10 is a light projector ST that constitutes a photoresponsive switch.
and receiver SR, and move between emitter ST and receiver SR.
When the optical coupling state of Trigger vibrator RMM. The output C of the retrigger type monostable multivibrator RMM has a predetermined pulse width T as shown in FIG. Note that the output C' of the retrigger type monostable multivibrator RMM is the output when triggered only by the output pulse b of the monostable multivibrator MM. The pulse width T is the hydraulic switching valve V.
L is opened and hydraulic pressure is supplied to the hydraulic cylinder SL. Within this time, the head portion HD of the piston rod PS has reached a sufficient distance to pass through the receiving focus of the reflected light from the object to be determined 10. , and the head portion HD is the object to be determined 1
Move a distance shorter than the distance it touches 0. During this time, the light emitting element LED emits light by the output of the constant voltage power supply circuit, and the light is projected onto the object to be determined 10 via the light projecting lens LT and filter FT. The reflected light from the object to be determined 10 is
The light is received by a light receiving element PH such as a phototransistor via a filter FR and a light receiving lens LR. Therefore, the reflected light from the object to be determined 10 detected by the light receiving element PH is detected as a change in the voltage drop across the resistor R2, and the voltage drop across the resistor R2 is changed by the inverting amplifier AMP.
The characteristics are as shown in the output characteristic diagram of the light-amount detection means shown in FIG. Therefore, when the output d of the inverting amplifier AMP is higher than the threshold voltage vth at the connection point voltage with the potentiometer PM, the output of the comparator COMP is "H" (high level).
The retrigger type monostable multivibrator RMM is triggered at the falling edge of the signal, and the output C of the retrigger type monostable multivibrator RMM becomes an output with a pulse width of less than the predetermined pulse width of 2T, as shown in Figure 4. Become. During this pulse width time, the hydraulic switching valve VL is opened and hydraulic pressure is supplied to the hydraulic cylinder 3m, so that the head HD of the piston rod PS presses the object 10 to be discriminated and transfers the object 10 to be discriminated. Route main roller conveyor 1
1 to the sub-roller conveyor 12 side.

As described above, the object discrimination device based on light reflection of this embodiment includes a light source means consisting of a light emitting element LED, a light projecting lens LT, and a filter FT for illuminating the object to be discriminated 10, and a filter FR and a light receiving lens LR. and a relative distance changing means such as a piston rod PS of a hydraulic cylinder SL that changes the distance between the object to be determined 10 and the light amount detecting means. , an inverting amplifier AMP for amplifying the output of the light-receiving element PH for determining the output state of the light quantity detecting means, and an output discriminating means consisting of a converre 900 MP for discriminating against a predetermined threshold value.

However, in the above embodiment, the light source means for illuminating the object to be determined includes a light emitting element LED, a projection lens LT, and a filter FT.
When carrying out the present invention, the light emitting element LED is not limited to elements such as light emitting diodes, and general lighting lamps can be used. Furthermore, the filter FT can be omitted depending on the type of light emitting element LED or illumination lamp. In addition, when using a light source with a lens such as a light emitting element LED or other lamp,
The light projecting lens LT can be omitted. However, it is necessary to use a filter F or a light emitting element L of a specific wavelength.
In the case of using an ED, the influence of disturbance can be removed by protecting the projection lens LT and selecting its wavelength.

When the relative distance to the object to be determined changes, the light source means for illuminating the object to be determined normally becomes brighter in inverse proportion to the square of the distance. Try to get parallel or convergent rays,
It is designed to eliminate changes in brightness due to distance, and its characteristics are that the peak value at the focal point of the light receiving lens LR can be increased, and the change in output is increased in response to changes in reflectance. be able to. Incidentally, in the case of a convergent light beam, when the relative distance to the object to be determined changes, the position of illumination by the light source means changes.

Further, in the above embodiment, the light source means, the optical system means, and the light amount detection means are built into the main body housing MH of the head HD and are integrally formed. The means can be external. In this case, it is desirable that the change in the distance between the light source and the object to be determined is such that the degree of change in the brightness of the object to be determined is small.

In other words, the distance between the light source and the object to be determined is increased, and one or more light sources are moved forward t2 to such an extent that the brightness of the object to be determined does not change even when the distance to the object to be determined changes slightly. desirable. Of course, ceiling lighting may also be used.

In the above embodiment, a light beam consisting of an optical system means and a light receiving element is used.
As the amount detection means, a filter FR and a light receiving lens LR are used.
The filter FR has an optical system means consisting of a light receiving element PH and a photoelectric detection means consisting of a light receiving element PH.The filter FR, like the former filter FT, protects the light receiving lens LR and suppresses the influence of disturbance by selecting its wavelength. In addition, the characteristics of the light receiving element PH can be matched. The light-receiving lens LR sets the focus at a predetermined distance, and its output characteristic is to obtain the peak value of the light-receiving element PH.The light-receiving lens LR is coated to have the function of a filter FR. In this case, filter FR can be omitted. Even if the former filter FT is omitted, the effect can be improved by using the filter FR.

In addition, as the light receiving element PH, a phototransistor, c
It is possible to use photosensitive elements such as ds, photodiodes, etc.

In the above embodiment, the relative distance changing means for changing the distance between the object to be discriminated and the photo-electric detection means changes the relative distance between the two by changing the arm length of the piston rod PS of the hydraulic cylinder SL. However, when carrying out the present invention, the object to be determined 10 is transported by means of transporting the object to be determined, such as the main roller conveyor 11.
transferred in the direction of the electricity detection means or in the direction opposite to the photo-electricity detection means;
It is also possible to utilize the relative distance change at this time.

Further, the hydraulic cylinder SL may be replaced with a rack and pinion gear. Note that when the hydraulic cylinder SL is used as in this embodiment, the driving force is large, and in addition to the discrimination of the object to be discriminated 10, it is also possible to discriminate the object to be discriminated 10.
It can also be used to change the direction of movement. In addition, in the case where the relative distance changing means for changing the distance between the object to be discriminated and the photo-electric detection means is configured using a rack and a pinion gear, the arm length of the rack can be adjusted arbitrarily by means of rotating the pinion gear. can be controlled.

In the above embodiment, as output discrimination means for determining the output state of the photo-electrical detection means, an inverting amplifier AMP amplifies the output of the light receiving element PH, and a comparator C discriminates the output from a predetermined darkness value.
Although it is composed of an OMP or the like, the output of the light receiving element PH may be digitally processed by a microcomputer via an A/D converter. Naturally, digital processing may be performed using a microcomputer with a built-in A/D converter. Further, the comparison means is not limited to the comparator COMP, and a comparison circuit capable of setting a threshold value such as a Schmitt circuit, an operational amplifier, or a differential amplifier can be used.

Further, this comparison means may be configured to output a signal to the light receiving element PH only when the brightness is equal to or higher than a predetermined brightness.

In the above embodiment, only the change in reflectance of the object to be determined is explained, but by selecting the type of filter,
It can also be used to determine the color of an object to be determined.

[Effects of the Invention] As described above, the object discrimination device by light reflection of the present invention includes a light source means for illuminating the object to be discriminated, a photo-electric detection means comprising an optical system means and a light receiving element, and the object to be discriminated. The apparatus is equipped with a relative distance changing means for changing the distance between the photo-electric detecting means, and an output discriminating means for determining the output state of the photo-electric detecting means. By changing the distance between the detection means, it is determined whether the output exceeds a predetermined threshold value and the object to be discriminated is discriminated. Therefore, the object to be discriminated and the detection element of the optical system are There is no need to set the distance to a predetermined distance with high precision. Therefore, the device can be made inexpensive.

By changing the distance between the object to be discriminated and the photo-electric detection means, it is determined whether the output is equal to or greater than a predetermined threshold, which facilitates the discrimination of moving objects. .

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of an object discrimination device based on light reflection according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the structure of an object discrimination device based on light reflection according to an embodiment of the present invention arranged on an object transport path. FIG. 3 is a circuit diagram of the object discrimination circuit based on light reflection of the embodiment shown in FIG. 2, and FIG.
The timing chart of the control by the object discrimination circuit based on light reflection of the first embodiment shown in the figure is shown, and FIG. 5 is an output characteristic diagram of the photo-electric detection means. In the figure, 10: object to be determined, 11: main roller conveyor, 12: sub roller conveyor, S = light emitter, sR: light receiver, SL: hydraulic cylinder, LED: light emitting element, PH: light receiving element. In addition, in the figures, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (7)

[Claims] (1) A light source means for illuminating the object to be discriminated, a photo-electric detection means consisting of an optical system means and a light receiving element, and a relative distance changing means for changing the distance between the object to be discriminated and the photo-electric detection means. and an output determining means for determining the output state of the photo-electrical detecting means. (2) Light reflection according to claim 1, characterized in that the light source means for illuminating the object to be determined, and the photo-electric detection means consisting of an optical system means and a light receiving element are integrally formed. object discrimination device. (3) The light source means for illuminating the object to be determined, the photo-electric detection means consisting of the optical system means and the light receiving element are integrally formed and attached to the piston rod of the relative distance changing means. An object discrimination device based on light reflection according to claim 1. (4) According to any one of claims 1 to 3, the photo-electric detection means comprising the optical system means and the light receiving element comprises a filter, a lens, and the light receiving element. Object discrimination device based on light reflection. (5) Any one of claims 1 to 4, wherein the relative distance changing means for changing the distance between the object to be determined and the photo-electric detection means is a hydraulic cylinder. 1. An object discrimination device based on light reflection according to item 1. (6) The relative distance changing means for changing the distance between the object to be determined and the photo-electric detection means comprises a rack and a pinion gear. An object discrimination device based on light reflection according to any one of the above. (7) Claims 1 to 4, characterized in that the relative distance changing means for changing the distance between the object to be determined and the photo-electric detection means comprises means for transporting the object to be determined. An object discrimination device based on light reflection according to any one of the items.