JP2009110876A - Movable part position detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a movable part position detection system capable of detecting in high precision a movement position of the movable part brought to different positions. <P>SOLUTION: The movable part position detection system includes a detecting means to detect the different movement positions of the movable part as a detection object and this detecting means has a light emitting element and a light receiving element arranged mutually facing each other and a shading plate which is arranged between these light emitting element and light receiving element and is interlocked with the movable part. The shading plate includes transmission openings of different opening area corresponding to the movement positions of the movable part and a reference opening of a prescribed opening area different from the transmission openings is installed between the transmission openings corresponding to these movement positions. Then, the shading plate is made to stop and move in moderation at the position of the reference opening between the transmission openings together with the movable part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a movable part position detection system that can detect the movement position of a movable part brought to a different position with high accuracy.

Conventionally, it is composed of a plurality of switches combined in multiple stages, such as a vehicle combination switch, and has a large number of mechanical switching contacts. Therefore, in many cases, the structure is complicated and the number of parts is large. Therefore, it is necessary to constantly pay attention to the wear and the poor contact of the contact portion.
Therefore, in order to solve the inconvenience resulting from such a mechanical structure, a contactless and non-contact type combination switch has been recently proposed with fewer mechanical contacts.

For example, in the combination switch disclosed in Patent Document 1, a shield plate that blocks light from the light emitting element is attached to the front surface of the photosensor, and the value of the photosensor is read by moving the shield plate according to the movement of the lever. The position of the lever is detected.
That is, since the shielding plate disposed at the tip of the lever rotates at an angle corresponding to the pivoting angle of the lever, the amount of light blocked by the shielding plate changes in multiple stages, thereby The output changes in multiple stages and multi-value switching is performed.

  On the other hand, in Patent Document 2, by changing the light path between the light guide plate and the shielding plate, the lever position is detected by switching the output to a plurality of optical sensors.

JP-A-8-273492 Japanese Patent Laid-Open No. 11-306925

However, in Patent Document 1,
(1) Since the amount of light is changed by the shielding plate, if a large number of detection positions are provided, the change in the amount of light becomes small, and the detection accuracy decreases. That is, as shown in FIG. 6, if the detection width is narrow, the accuracy is lowered due to the influence of noise and temperature characteristics, which causes malfunction.
(2) The detection accuracy varies depending on the temperature characteristics of the light detection element, and a large number of detection positions cannot be provided. Although it is possible to make the temperature characteristics of the light detecting elements uniform on the light emitting side and the light receiving side, an increase in cost is inevitable.
Furthermore, Patent Document 2 requires a large number of light receiving elements.
The present invention has been proposed in order to improve the above-described problems. By adopting a new light-shielding method, light is shielded at adjacent detection positions due to the presence of a large number of detection positions. It is an object of the present invention to provide a movable part position detection system that can detect with high accuracy without a decrease in detection accuracy due to a small difference in light quantity.

  In order to solve the above-described problem, the invention according to claim 1 includes a detection unit that detects different movement positions of the movable portion as a detection target, and the detection unit includes a light-emitting element and a light-receiving element arranged to face each other. And a light-shielding plate disposed between the light-emitting element and the light-receiving element and interlocking with the movable part. The light-shielding plate has transmission apertures having different opening areas corresponding to the moving position of the movable part. In addition, a reference opening having a predetermined opening area different from that of the transmission opening is provided between the transmission openings corresponding to these moving positions, and the light shielding plate together with the movable part is located at the position of the reference opening between the transmission openings. It is characterized in that it is configured to stop / move in moderation.

  As a result, each reference opening can be used as a reference by moderatingly stopping / moving the light shielding plate together with the movable portion at the position of the reference opening between the transmission openings. Each moving position of the movable part can be reliably captured.

  According to a second aspect of the present invention, there is provided detection means for detecting different moving positions of the movable part as a detection target, and the detection means and the light-emitting element arranged so as to face each other and interlock with the movable part Element and a light-shielding plate disposed between the light-emitting element and the light-receiving element. The light-shielding plate is provided with transmission openings having different opening areas corresponding to the moving position of the movable part. A reference opening having a predetermined opening area different from that of the transmission opening is provided between the transmission openings corresponding to the moving position, and the light emitting element and the light receiving element together with the movable part are positioned between the transmission openings. It is characterized in that it is configured to stop / move in moderation.

  Accordingly, the light emitting element and the light receiving element together with the movable part can be stopped / moved modestly at the position of the reference opening between the transmission openings, so that each reference opening can be used as a reference. Therefore, each moving position of the corresponding movable part can be reliably captured.

Hereinafter, a movable part position detection system according to the present invention will be described with reference to the accompanying drawings showing preferred embodiments.
FIG. 1 schematically shows detection means 1 in the movable part position detection system. The detection means 1 detects different movement positions of a movable part (not shown) as a detection target.
In addition, the movable part is assumed to be an operation means provided with a known moderation mechanism, for example, an operation lever of a combination switch, or an operation means for outputting a state signal and positioning it for operation control by positioning in multiple stages.
The detecting means 1 has a configuration in which a light emitting element 2 and a light receiving element 3 arranged to face each other, and a light shielding plate 4 interlocking with a movable portion is disposed between the light emitting element 2 and the light receiving element 3.
The light shielding plate 4 is provided with a transmissive opening 5 having a different opening area so that the amount of transmitted light varies according to the position of the movable part. That is, the light-shielding plate 4 is provided with a rectangular transmission opening 5 having a different opening area at each position (a, b, c, d, e, f, g, h, i, j) of the movable part. (See FIG. 3).

The light-emitting element 2 and the light-receiving element 3 arranged to face each other transmit light emitted from the light-emitting element 2 (LED 2) through the transmission opening 5 of the light-shielding plate 4, and the transmitted light is received by the light-receiving element 3 (phototransistor). A well-known photosensor circuit PC (see FIG. 2) is configured to receive in 3) and output as a corresponding detection voltage signal.
Then, the detection voltage signal obtained by the photosensor circuit PC is subjected to predetermined signal processing as will be described later, and as shown in FIG. 4, the transmission opening 5 formed in the light shielding plate 4 shown in FIG. The output voltage waveform is obtained corresponding to the positions (a, b, c, d, e, f, g, h, i, j).
This means that if the opening area of the transmissive opening 5 is appropriately set, the amount of transmitted light can be adjusted, and an output voltage specifying the detection position can be obtained.
Here, for example, at the position a, the output voltage Va is maximum (the amount of transmitted light is maximum), and at the adjacent position b, the output voltage Vb is significantly different from the output voltage Va at the position a. . Further, a reference opening Ho having a predetermined opening area is provided between the detection position a and the adjacent detection position b so that a predetermined output voltage Vo can be obtained.
Further, in the subsequent positions (c, d, e, f, g, h, i, j) of the transmission openings 5 formed in the light shielding plate 4, the output voltages at adjacent positions are discrete. In addition, a reference opening Ho having a predetermined opening area is provided between the detection positions so that a predetermined output voltage Vo can be obtained.

  The light shielding plate 4 is positioned and connected to a movable portion provided with a moderation mechanism so as to be stopped / moved moderately at the position of the reference opening Ho between the transmission openings 5.

Next, FIG. 5 is a block diagram showing a schematic configuration of the movable part position detection system according to the present invention.
In other words, this movable part position detection system is obtained by performing signal processing (detection voltage filtering, voltage amplification or attenuation, analog-digital conversion) on the detection voltage signal relating to the transmitted light amount obtained by the photosensor circuit PC. Based on the output voltages Va to Vj, a determination process described later is performed in the determination circuit, and a signal relating to the detection position is output. Note that the output signal applied to the detection position may be any of serial, analog, and parallel outputs.

Although the description of the specific configuration of the determination circuit is omitted, it is conceivable to perform the following steps based on the output voltage shown in FIG.
First, based on the output voltage Vo at the reference opening Ho from the output voltages Va to Vj at each detection position and the output voltage Vo at the reference opening Ho between the detection positions, detection is made based on whether the output voltage is high or low. It is possible to determine the position and specify the detection position using each voltage value as a criterion. Note that each output voltage shown in FIG. 4 is adjusted for the determination value of each output voltage in consideration of the influence of the temperature and use environment on the phototransistor 3 which is a light receiving element in the photosensor circuit PC.
For example, the output voltage Va should originally be output at the detection position a, but even if, for example, Vc is output depending on the environment, the output voltage Vo ′ can be obtained in a state where the movable portion is stopped. The detected voltage is corrected to Va ′ (= Vc).
If the output value is high (for example, detection position a to detection position b) or the output value is low (for example, detection position d to detection position e), the detection position has changed by one. It is possible to determine.

In the movable part position detection system as described above, when the movable part (operation lever) is moved by a switch operation, the light shielding plate 4 is interlocked. The light shielding plate 4 is moderately stopped / moved at the position of the reference opening Ho between the transmission openings 5 by a moderation mechanism provided in the movable part.
Thereby, in the optical path from the light emitting element 2 to the light receiving element 3 in the photosensor circuit PC, the transmission openings 5 from the detection position a to the detection position e of the light shielding plate 4 are respectively provided across the reference opening Ho. Transmitted light is incident on the light receiving element 3 in accordance with the position of the transmission opening 5 of the light shielding plate 4.
Then, the photosensor circuit PC can output a detection voltage signal corresponding to the amount of transmitted light.

The detected voltage signal from the photosensor circuit PC is subjected to signal processing (output voltage filtering, voltage amplification or attenuation, analog-digital conversion) in the movable part position detection system, and as shown in FIG. Voltages Va to Vj are obtained.
In the determination circuit, whether the output voltage is high based on the output voltage Vo at the reference opening Ho from the output voltages Va to Vj at each detection position and the output voltage Vo at the reference opening Ho between the detection positions. It is possible to determine the detection position when the value is low and specify the detection position using the output voltage Vo at each reference opening Ho as a determination reference. In addition, each output voltage shown in FIG. 4 can adjust the judgment value of each output voltage in consideration of the influence of the temperature and use environment on the phototransistor 3 which is a light receiving element in the photosensor circuit PC.
In the determination circuit, one detection position is detected due to a change such as a low output value (for example, detection position a to detection position b) or a low output value (for example, detection position d to detection position e). It is possible to determine that it has changed.

As described above, in the present invention, the light shielding plate 4 is provided with the transmission openings 5 having different opening areas corresponding to the moving positions of the movable parts, and the transmission openings 5 are adjacent to the transmission openings. Since the aperture areas are greatly different between the five, the amount of transmitted light varies discretely even at adjacent detection positions, so high-precision detection is possible without being affected by noise or temperature characteristics. Is possible.
Further, the light shielding plate 4 together with the movable portion stops modestly at the reference opening Ho between the transmission openings 5, and corrects the detection voltage that is a specific position based on the detection voltage at the reference opening Ho. Therefore, malfunctions can be suppressed regardless of the operating environment.

As mentioned above, although an example was given and demonstrated about the movable part position detection system concerning this invention, this invention can also be comprised as follows.
That is, the light shielding plate 4 does not move back and forth in the optical path from the light emitting element 2 to the light receiving element 3 in the photosensor circuit PC in conjunction with the movable part, but the light emitting element 2 and the light receiving in the photosensor circuit PC. The element 3 side may be interlocked with the movable part.

  According to the present invention, as a new light shielding method, the light shielding plate is provided with transmission openings having different opening areas corresponding to the movement positions of the movable parts, and between the transmission openings corresponding to the movement positions. By providing a reference opening having a predetermined opening area different from that of the transmission opening and stopping / moving the light shielding plate together with the movable part at the position of the reference opening between the transmission openings, Detection position does not cause a decrease in detection accuracy due to a small difference in the amount of light to be shielded between adjacent detection positions, and at a specific position with reference to the detection voltage at the reference opening. Since it is possible to correct the detected voltage that is considered to be present, malfunction can be suppressed regardless of the operating environment.

It is a typical perspective view which shows an example of the detection means in the movable part position detection system concerning this invention. It is a circuit diagram which outputs the detection signal by the detection means shown in FIG. 1 as a detection voltage signal. It is a typical perspective view which showed the arrangement | positioning relationship between the light receiving element and the shielding board in the detection means shown in FIG. It is a graph which shows the relationship between the detection position of a movable part, and the output voltage value corresponding to the detection position. It is a block diagram which shows schematic structure of the movable part position detection system concerning this invention. It is the graph which showed an example of the relationship between the detection position of an operation lever, and a detection output signal for demonstrating the inconvenience at the time of detecting the position of an operation lever with the conventional detection method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Detection means 2 Light emitting element 3 Light receiving element 4 Light-shielding plate 5 Transmission opening part Ho Reference | standard opening part PC Photo sensor circuit

Claims (2)

Comprising a detecting means for detecting different moving positions of the movable part as a detection target;
The detection means includes a light emitting element and a light receiving element arranged to face each other, and a light shielding plate arranged between the light emitting element and the light receiving element and interlocked with the movable part,
The light shielding plate is provided with a transmission opening having a different opening area corresponding to the moving position of the movable part, and
Between the transmission openings corresponding to these movement positions, a reference opening having a predetermined opening area different from the transmission openings is provided,
The movable part position detection system, wherein the light shielding plate is stopped and moved modestly at the position of the reference opening between the transmission openings together with the movable part. Comprising a detecting means for detecting different moving positions of the movable part as a detection target;
The detection means includes a light emitting element and a light receiving element arranged to face each other and interlocked with the movable portion, and a light shielding plate arranged between the light emitting element and the light receiving element,
The light shielding plate is provided with a transmission opening having a different opening area corresponding to the moving position of the movable part, and
Between the transmission openings corresponding to these movement positions, a reference opening having a predetermined opening area different from the transmission openings is provided,
The movable part position detection system characterized in that the light emitting element and the light receiving element together with the movable part are configured to stop / move modestly at the position of the reference opening between the transmission openings.

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