JPH0452830Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a movement direction detection device that optically detects the movement direction of a movable member, and for example, detects the rotation direction of a capstan motor or reel motor in a tape recorder. used for detection.

[Summary of the idea]

The present invention uses a photodetector with a structure in which one light-emitting element and two light-receiving elements are housed and arranged in a common package in a moving direction detection device that optically detects the rotational direction of a motor. Therefore, it is possible to reliably detect the direction of relative movement between the photodetector and the reflecting plate on which a striped reflection pattern with a predetermined repeating pitch is formed.

[Conventional technology]

Conventionally, a moving direction detecting device that optically detects the rotational direction of a motor, etc., uses two optical devices facing a reflection pattern 41 of a predetermined repeating pitch provided on a rotating body 40, as shown in FIG. 4, for example. A configuration in which sensors 42 and 43 are arranged is generally known, and as shown in FIG. The direction of rotation of the rotating body 40 is detected by reading the detection output Sb of the other optical sensor 43 and determining whether the value is logical "H" or logical "L".

Furthermore, the detection output of one of the optical sensors 42 and 43 in the moving direction detection device is used to measure the repetition period and detect the rotational speed of the rotating body 40.

Note that each of the optical sensors 42 and 43 is as follows:
For example, as shown in FIG. 6, a light emitting diode 45 and a phototransistor 46 housed in a package 47 are used.

[Problem that the invention attempts to solve]

By the way, in conventional movement direction detection devices, in order to reliably determine the movement direction of a rotating body based on the detection outputs of two optical sensors, there is a phase difference of 90 degrees in electrical angle between each detection output. It is necessary to adjust the installation position of each optical sensor, especially,
If an attempt is made to increase the number of waves output per revolution to increase the speed detection accuracy, it will take a great deal of effort to adjust the placement positions of the two optical sensors.

Therefore, in view of the above-mentioned conventional problems, the present invention is capable of reliably detecting the direction of movement without requiring any effort to adjust the placement position of the optical sensor even when using a reflection pattern with fine repeating pitches. It is an object of the present invention to provide a moving direction detection device having a novel configuration.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention arranges two light-receiving elements apart by a predetermined distance D, and also arranges one light-emitting element between the two light-receiving elements. A photodetector comprising an element and a light emitting element housed in a common package;
Along the arrangement direction of each element constituting the photodetector, the length D/N is the distance D divided by an integer N.
and a reflector plate formed with a striped reflection pattern of a repeating pitch P other than the above, and the direction of relative movement between the photodetector and the reflector plate is detected based on each photodetection output from the two light receiving elements. It is characterized by what it did.

[Effect]

In the movement direction detecting device according to the present invention, the reflected light from a reflection pattern of a predetermined repeating pitch is detected by a photodetector having one light emitting element arranged between two light receiving elements. The direction of relative movement between the patterned reflector and the photodetector is detected. The two light-receiving elements and the one light-emitting element have a fixed mutual positional relationship within the photodetector package, and there is no need to perform positional adjustment when installing the photodetector.

〔Example〕

Hereinafter, one embodiment of the moving direction detection device according to the present invention will be described in detail with reference to the drawings.

The movement direction detecting device of the embodiment shown in FIGS. 1 to 3 is designed to detect the rotational direction of a capstan motor, and is designed to detect the rotational direction of a capstan motor. a photodetector 20 installed so as to face a radial striped reflection pattern that repeats a white pattern 11 and a black pattern 12 formed on the reflection plate 10; a signal processing circuit 30 that performs signal processing on the detection output from the device 20;
It is composed of.

In this embodiment, as schematically shown in the cross-sectional view of FIG.
A common package 24 includes two phototransistors 21 and 22 and a light emitting diode 23 arranged as a light emitting element between the two phototransistors 21 and 22. The package 24 has light guide windows 24a, 24b, and 24c formed in portions corresponding to the phototransistors 21 and 22 and the light emitting diode 23, respectively, and detects light from the light emitting diode 23 through the light guide window 24c. The above reflector plate 10
and the reflected light is transmitted to each of the light guide windows 24a,
24b, each of the phototransistors 21,
The light is guided to the light receiving portion of 22. In this embodiment, the light reflected by the reflection plate 10 of the detection light emitted by the light emitting diode 23 disposed between the two phototransistors 21 and 22 separated by a distance D is transferred to the two phototransistors 21 and 22.
, the phototransistor 21,
As shown in FIG. 1, the reflection position of the detection light detected by the detector 22 by the reflecting plate 10 is separated by a distance of D/2.

Further, the photodetector 20 is mounted on the reflection plate 10.
The white pattern 11 and the black pattern are arranged at a repeating pitch P that is twice the distance D, that is, 2D, along the arrangement direction of each element, that is, the two phototransistors 21 and 22 and one light emitting diode 23. A striped reflection pattern repeating pattern 12 is formed.

Further, the photodetector 20 is connected to a signal processing circuit 30 as shown in the circuit diagram of FIG.

That is, the two phototransistors 2
1, 22, each collector terminal 21c, 22c is connected to the power supply terminal 31, each emitter terminal 21e, 22e is connected to each base of transistor 32, 33, and resistor 34, 35
is grounded through. Further, the light emitting diode 23 has its anode terminal 23a connected to the power supply terminal 31 via a resistor 36, and its cathode terminal 23k grounded. Further, each of the transistors 32 and 33 has one collector connected to the data input terminal of the D-type flip-flop 39, and the other collector connected to the clock input terminal of the D-type flip-flop 39. It is connected to the power supply terminal 31 via resistors 37 and 38, and each emitter is grounded.

In the embodiment configured as described above, the reflecting plate 10
Due to the relative movement between the light detector 20 and the photodetector 20, the phase becomes an advanced phase or a delayed phase depending on the direction of the relative movement, with a period T corresponding to the repetition pitch P of the striped reflection pattern formed on the reflection plate 10. Detection outputs having a phase difference of 90° are obtained from each phototransistor 21, 22 of the photodetector 20. The D-type flip-flop 39 of the signal processing circuit 30 is supplied with each detection output obtained from each of the phototransistors 21 and 22, and the D-type flip-flop 39 receives the data input that is supplied to the data input terminal via the transistor 32, that is, one of the phototransistors. 2
The reflection plate 10 and A Q output of a logical value corresponding to the direction of relative movement with respect to the photodetector 20 is output. In this embodiment, the D-type flip-flop 39 includes the reflector 10 and the photodetector 2.
If the direction of relative movement with respect to 0 is, for example, the direction of arrow A shown in FIG. 3, a Q output of logic "L" will be obtained, and if the direction of relative movement with respect to arrow B is the direction of arrow B, a Q output of logic "H" will be obtained. In addition, in FIG. 3, to indicates that the photodetector 20 is at the center position shown by a thick solid line with respect to the reflector 10, and a thin line moving in the direction of arrow A from the center position to indicates The position indicated by ta is indicated by ta, and the position indicated by a thin line moved in the direction of arrow B from the central position to is indicated by tb.

In this embodiment, two phototransistors 2
By using the photodetector 20 in which one light emitting diode 23 is arranged between the phototransistors 1 and 22, the photodetector 20 is installed with the distance D between the phototransistors 21 and 22 always kept constant. Therefore, by detecting the light reflected by the reflection pattern of the predetermined repeating pitch P formed on the reflection plate 10 with the photodetector 20, the relative movement between the reflection plate 10 and the photodetector 20 can be detected. Direction can be detected reliably. Furthermore, the moving direction detecting device of this embodiment does not require adjustment of the arrangement positions of the respective constituent elements of the photodetector 20, that is, the two phototransistors 21 and 22 and the one light emitting diode 23. is easy.

In this embodiment, two phototransistors 21 and 22 constituting the photodetector 20 are
Reflector plate 10 formed with a striped reflection pattern with a repeating pitch P that is twice the installation interval D, that is, 2D.
Each of the phototransistors 21 and 22 is
Detection outputs having a phase difference of 90° from each other are obtained, but in principle, the repetition pitch P of the striped reflection pattern of the reflection plate 10 is determined by setting the installation interval D of the phototransistors 21 and 22 to an integer N. Any length other than the length divided by D/N is sufficient.

[Effect of idea]

As is clear from the description of the embodiments described above, in the moving direction detecting device according to the present invention, a reflection pattern with a predetermined repeating pitch is detected using a photodetector in which one light emitting element is arranged between two light receiving elements. It is possible to reliably detect the direction of relative movement between the reflective plate provided with the reflective pattern and the photodetector by detecting the reflected light by Since the mutual positional relationship of the photodetector is fixed within the package, there is no need to adjust the position when installing the photodetector.
Easy to assemble.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing the main structure of an embodiment of the moving direction detection device according to the present invention, and FIG. 2 is a circuit diagram showing the electrical structure of the above embodiment. FIG. 3 is a timing chart showing the operation of the above embodiment. FIG. 4 is a schematic perspective view showing the configuration of a conventional example of a moving direction detection device, and FIG.
The figure is a timing chart showing the operation of the conventional example, and FIG. 6 is a sectional view schematically showing the structure of the optical sensor used in the conventional example. 10...Reflector, 11...White pattern, 12...
...Black pattern, 20...Photodetector, 21, 22...
...Phototransistor, 23...Light emitting diode, 30...Signal processing circuit, 39...D type flip-flop.

Claims (1)

[Claims for Utility Model Registration] Two light-receiving elements are arranged at a predetermined distance D, and one light-emitting element is arranged between the two light-receiving elements, and the light-receiving element and the light-emitting element are arranged. A photodetector housed in a common package, and a length D/divide the distance D divided by an integer N along the arrangement direction of each element constituting the photodetector.
and a reflecting plate formed with a striped reflection pattern with a repeating pitch P other than N, and detects the direction of relative movement between the photodetector and the reflecting plate based on each photodetection output from the two photodetectors. A moving direction detection device characterized by: