JPH05118877A - Device for detecting amount of traveling - Google Patents

Abstract

PURPOSE:To enable traveling of a traveling member to be detected with a simple configuration. CONSTITUTION:A slider 5 which consists of acryl resin is provided between a light-projection element 3 and a light-reception element 4 so that it can travel. A groove part 6 with an inclined surface 6a is formed on a surface of the slider 5 at a constant interval. The groove part 6 has the inclined surface 6a and reflects light from the light-projection element 3 in horizontal direction when it is positioned at a detection region between the light-projection element 3 and the light-reception element 4 accompanying traveling of the slider 5. Therefore, since a light path from the light-projection element 3 to the light- reception element 4 is formed intermittently along with traveling of the groove part 6, the groove part 6 and further traveling of the slider 5 can be detected based on a light-reception state of the light-reception element 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving amount detecting device for detecting a moving amount of a moving member which moves between a light emitting element and a light receiving element.

[0002]

2. Description of the Related Art In a rotary encoder, for example, a plurality of slits are radially formed on the outer peripheral side of a circular disk, and a pair of a light emitting element and a light receiving element are arranged so as to sandwich a movement locus of the slits. ing.
According to such a configuration, when the slit moves along with the rotation of the circular disc, the optical path from the light projecting element to the light receiving element is intermittently formed according to the movement of the slit,
A pulsed light receiving signal is output from the light receiving element. Therefore, the amount of movement of the slit and thus the amount of rotation of the circular disk can be detected based on the output state of the detection signal from the light receiving element.

Here, the slits of the above-mentioned circular disk are generally formed by punching with a press or by chemical treatment by etching.

[0004]

By the way, in order to punch a slit with a press, the size of the slit must be set relatively large from the viewpoint of the machining accuracy of the die, and it is difficult to increase the detection resolution. There is a drawback that Further, when the slits are formed by etching, although the width dimension of the slits can be set small and high detection resolution can be obtained, there is a drawback that the cost becomes high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a movement amount detecting device capable of enhancing the detection resolution without increasing the cost.

[0006]

A movement amount detecting device of the present invention is provided with a light projecting element and a light receiving element facing each other, and is movable so as to intersect with an optical axis between the light projecting element and the light receiving element. In addition, a resin-based moving member that allows the light from the light projecting element to pass therethrough is provided, and the surface of the moving member is inclined to reflect the light from the light projecting element to the light receiving element at regular intervals along the moving direction of the moving member. A groove having a surface is formed.

[0007]

The light from the light projecting element reaches the light receiving element through the moving member made of resin. Then, when the moving member moves,
When the groove provided on the moving member also moves and the inclined surface of the groove is located on the optical axis between the light projecting element and the light receiving element, the light from the light projecting element is reflected by the inclined surface and does not reach the light receiving element. .. As a result, the amount of light entering the light receiving element changes according to the movement of the moving member, so that the moving amount of the moving member can be detected based on the light receiving state of the light receiving element. In this case, by forming the groove portion integrally with the moving member,
The groove can be easily formed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
Will be described. In FIG. 3 showing the side of the device,
The support 1 is formed in a hollow shape, a light emitting element 3 made of an LED is arranged on the upper surface of the inner peripheral surface 2, and a light receiving element 4 made of a photodiode or a phototransistor on the lower surface.
Are arranged. Here, the light from the light projecting element 3 is converted into parallel light by a lens (not shown) and applied to the light receiving element 4.

A groove 2a is formed on the inner peripheral surface 2 of the support 1, and a slider 5 as a long flat plate-like moving member is linearly movable in the groove 2a. The slider 5 is formed of a transparent acrylic material, and V-shaped groove portions 6 are formed on the lower surface of the slider 5 at regular intervals (see FIG. 1).

In FIG. 1 showing a longitudinal section of the apparatus, a groove 6 formed in a slider 5 has an inclined surface 6a, and the inclined surface 6a is formed at an angle of 45 ° with respect to the optical axis of the light projecting element 3. Has been done. In this case, the slider 5 is formed by resin molding using a mold, and the groove portion 6 is formed collectively at the time of resin molding. The width dimension of the groove portion 6 and the interval from the end portion of the groove portion 6 to the end portion of the adjacent groove portion 6 are set to exceed the detection region width between the light projecting element 3 and the light receiving element 4.

Hereinafter, the state of light with which the groove 6 is irradiated with the light from the light projecting element 3 will be considered. As shown in FIG. 4, when light is incident on the boundary surface between the medium X and the medium Y, the light is refracted based on Snell's law and reflected light reflected at the same angle with respect to the normal line of the boundary surface. The transmitted light is divided into
Here, the refractive index of the medium X is n1, and the refractive index of the medium Y is n2.
, Where the incident angle is i and the refraction angle is r, the following equation is established according to Snell's law.

[0012]

[Equation 1] When the medium Y is air, n2 is approximately 1, so

[0013]

[Equation 2] Becomes

As the incident angle i shown in FIG. 4 increases, the amount of reflected light increases and the amount of transmitted light decreases. When the incident angle i is set so that the refraction angle r becomes 90 °, the intensity of the transmitted light becomes zero and the light is totally reflected at the boundary surface. At this time, the incident angle is is

[0015]

[Equation 3] Can be shown as Here, when the medium X is acrylic, since the refractive index of acrylic is about 1.5, the incident angle i
s is

[0016]

[Equation 4] Becomes Therefore, when the medium is acrylic, the incident angle i>
The incident light is totally reflected at 42 °.

In FIG. 5 showing the signal processing circuit, a light receiving signal from the light receiving element 4 is amplified by the amplifier 7 and then output to the comparator 8. The comparator 8 compares the signal level of the received light signal with the reference voltage from the voltage generator 9, and outputs a high level signal when the signal level of the received light signal exceeds the reference voltage. In this case, the reference voltage set in the voltage generator 9 is set to 1/2 of the maximum signal level of the received light signal.

Next, the operation of the above configuration will be described. When the slider 5 moves and the detection area between the light projecting element 3 and the light receiving element 4 is located between the groove portions 6 as shown in FIG. 7, the light from the light projecting element 3 passes through the slider 5 and the light receiving element. 4, the light receiving signal from the light receiving element 4 is at the maximum level (period shown by A in FIG. 12).

When the slider 5 moves and a part of the detection area is caught by the groove 6 as shown in FIG. 8, a part of the light from the light projecting element 3 is reflected in the lateral direction by the inclined surface 6a. (See FIG. 6). At this time, since the inclined surface 6a is set to be inclined by 45 ° with respect to the optical axis, the incident angle of light on the inclined surface 6a is 45 °. As a result, due to the relationship between the incident light and the reflected light described above, the light from the light projecting element 3 that reaches the inclined surface 6a is totally reflected at the boundary surface between the slider 5 and the air. Therefore, since the amount of light reaching the light receiving element 4 from the light projecting element 3 decreases in accordance with the movement of the groove portion 6, the signal level of the light receiving signal from the light receiving element 4 decreases in accordance with the movement of the slider 5 (in FIG. 12, (Period indicated by B).

When the slider 5 moves to cover the entire groove 6 with the detection area as shown in FIG. 9, all the light from the light projecting element 3 is reflected by the inclined surface 6a. As a result, the light from the light projecting element 3 is reflected by the groove 6 and does not reach the light receiving element 4, so that the signal level of the light receiving signal from the light receiving element 4 becomes zero level (period shown by C in FIG. 12). ..

When the slider 5 moves and a part of the detection area comes out of the groove 6 as shown in FIG. 10, the light from the light projecting element 3 enters the light receiving element 4, so that The signal level of the light receiving signal from the light receiving element 4 is increased (the period indicated by D in FIG. 12).

When the slider 5 moves and the detection area is completely escaped from the groove portion 6 as shown in FIG. 11, all the light from the light projecting element 3 enters the light receiving element 4, so that the light receiving element 4 The signal level of the received light signal of is the maximum level.

The light receiving signal output from the light receiving element 4 as described above is compared with the reference voltage by the comparator 8 and output as a binarized signal. Therefore, it is possible to detect the movement amount of the groove portion 6 and thus the slider 5 based on the binarized signal output from the comparator 8.

In short, according to the above embodiment, the slider 5 made of transparent acrylic resin is integrally formed with the groove portion 6 having the inclined surface 6a by a die, and the groove portion 6 is moved by the movement of the slider 5. Light emitting element 3 to light receiving element 4
Since the optical path leading up to is formed intermittently, unlike the conventional configuration in which the slit is formed on the rotary plate, the width of the groove portion 6 is set small without increasing the cost, and the detection resolution is increased. You can

FIGS. 13 and 14 show a second embodiment of the present invention, and the signal processing circuit for processing the received light signal is the same and therefore omitted. That is, the rotating disk 11, which is a moving member, is fixed to the rotating shaft 10. The rotating disk 11 is made of transparent acrylic. Here, the rotary disk 11 is formed by resin molding using a metal mold, and a groove portion 12 having an inclined surface is radially integrally formed on the lower surface thereof as shown in FIG. Further, a light projecting element 14 and a light receiving element 15 are arranged on the inner peripheral surface of the support body 13 supporting the rotating shaft 10 so as to face the movement trajectory of the groove 12.

In the case of the second embodiment, the rotating disk 11
When the groove 12 is positioned in the detection area between the light projecting element 14 and the light receiving element 15 with the rotation of, the light emitted from the light projecting element 14 to the light receiving element 15 is reflected by the groove 12 in the lateral direction. The amount of light received by the light receiving element 15 changes accordingly. Therefore, since the pulsed detection signal is output from the comparator 8 based on the light receiving signal from the light receiving element 15, the movement amount of the groove portion 12 and the rotation of the rotary disk 11 based on the detection signal is output as in the first embodiment. The amount can be detected.

FIG. 15 and FIG. 16 show a third embodiment of the present invention. 15 and 16, a ring 17 as a moving member is fixed to the rotating body 16.
The ring 17 is formed by molding a transparent acrylic resin with a mold, and a groove portion 18 having an inclined surface is integrally formed on the outer peripheral surface thereof. Further, a light projecting element 20 and a light receiving element 21 are arranged on a support 19 provided with the ring 16 sandwiched therebetween.

In the case of the third embodiment, when the ring 17 rotates with the rotation of the rotating body 16, the groove portion 18 moves and the optical path from the light projecting element 20 to the light receiving element 21 is intermittently formed. Therefore, the light receiving element 21 outputs a light receiving signal according to the amount of light received. Therefore, as in the first embodiment,
Based on the light receiving signal from the light receiving element 21, the amount of movement of the groove 18 and thus the amount of rotation of the rotating body 16 can be detected.

In each of the above embodiments, the groove is formed in a V shape having two inclined surfaces, but instead of this, FIG.
The groove portion 22 may be formed from one inclined surface 22a as shown in FIG.

[0030]

As is apparent from the above description, according to the movement amount detecting apparatus of the present invention, the light projecting element and the light receiving element are provided so as to face each other, and the optical axis between the light projecting element and the light receiving element is provided. A moving member that is movable so as to intersect and that reflects light from the light projecting element is provided, and light from the light projecting element to the light receiving element is provided on the surface of the moving member at regular intervals along the moving direction of the moving member. Since the groove portion having the inclined surface that reflects light is provided, the excellent effect that the detection resolution can be increased without increasing the cost is achieved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of essential parts showing a first embodiment of the present invention.

FIG. 2 is a bottom view of the main part

FIG. 3 is a plan view of a main part

FIG. 4 is a schematic diagram for explaining the operation.

FIG. 5 is a block diagram showing an electric circuit.

FIG. 6 is an enlarged vertical sectional view of a main part.

FIG. 7 is a view corresponding to FIG. 1 for explaining the operation.

FIG. 8 is a view corresponding to FIG. 1 in different operating states.

FIG. 9 is a view corresponding to FIG. 1 showing different operating states.

FIG. 10 is a view corresponding to FIG. 1 in different operating states.

FIG. 11 is a view corresponding to FIG. 1 in different operating states.

FIG. 12 is a signal waveform diagram showing a light receiving signal and a binarized signal.

FIG. 13 is a vertical cross-sectional view of a main part showing a second embodiment of the present invention.

FIG. 14 is a bottom view of the main part

FIG. 15 is a front view of the essential parts showing the third embodiment of the present invention.

FIG. 16 is a side view of the main part.

FIG. 17 is a view corresponding to FIG. 1 showing another embodiment of the present invention.

[Explanation of symbols]

3 is a light emitting element, 4 is a light receiving element, 5 is a slider (moving member), 6 is a groove portion, 6a is an inclined surface, 11 is a rotating disk (moving member), 14 is a light emitting element, 15 is a light receiving element, 17
Is a ring (moving member), 20 is a light projecting element, and 21 is a light receiving element.

Claims (1)

[Claims] 1. A light projecting element and a light receiving element that are provided so as to face each other, and a light that passes from the light projecting element is movably provided so as to intersect with an optical axis between the light projecting element and the light receiving element. A moving member made of a resin, and a groove portion provided on the surface of the moving member at regular intervals along the moving direction of the moving member and having a sloped surface for reflecting light from the light projecting element to the light receiving element. Characteristic movement amount detection device.