JPS63269002A - Apparatus for detecting position of body - Google Patents

Abstract

PURPOSE:To detect the position of a body, by operationally processing the light blocking phenomenon, which is generated by scanning one laser beam by a rotary mirror to reflect the same from the reflecting part provided to the peripheral surface of a detection area and projecting the reflected beam on the body, and the light blocking phenomenon detected by a beam receiving means. CONSTITUTION:The beam path of the laser beam L of a beam emitting element LD changes by the angle of rotation of a mirror 3. Beam L1 is reflected by the reflecting mirror 4 provided to the peripheral surface of an area 1 to reach a beam receiving element group PD 3 and beam L2 reaches a beam receiving group PD 4 and beam L3 directly goes to a beam receiving element group PD 4 but it is blocked by a body 5 and groups PD 3, 4 are arranged at the predetermined positions on the peripheral surface of the area 1 at arbitrary angles in an arbitrary number so as to continuously output the sum signal of the groups during the projection of the beams L1-L3. The laser beam L1 is blocked by the body 5 in the area 1 and the sum signal of a terminal 6 reduces (first beam blocking phenomenon). The laser beam L3 is blocked so as to provide time difference from the laser beam L1 and the sum signal of the terminal 6 reduces (second beam blocking phenomenon). The position of the body can be calculated by performing operational processing using both output signals corresponding to each other and, by this constitution, the number of beam emitting and receiving elements are reduced to make it possible to detect the position of the body.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an object position detection device configured to be able to detect the position of a light-blocking object within a specific area.

<Prior Art> As an example of a conventional position detection device for a light blocking object, a large number of light receiving element groups PDI are provided on two opposing sides of a rectangular detection area Z shown in FIG.

PD2 is arranged, and light emitting elements LDI, LD2 . LD3 and LD4 are arranged, and the diffused light from the light emitting elements LDI and LD2 is configured so that all of the light receiving element group PD2 arranged facing the light emitting elements LDI and LD2 can receive the light, and The light emitting element LD3. The diffused light from the LD4 is also configured to be received by all of the light receiving element groups PDI arranged facing the LD4, and when a light blocking object exists within the rectangular detection area Z, this light blocking object A system has been put into practical use in which the position of a light-shielding object is detected based on the position of each light-receiving element in a group of light-receiving elements in which a light-shielding phenomenon occurs in correspondence with the position of the light-shielding object.

<Problems to be Solved by the Invention> Although the object position detecting device of the prior art has considerably fewer light-emitting elements than the conventional one, it still uses a large number of light-receiving elements. Furthermore, since the number of light emitting elements is reduced, the light from one light emitting element is supplied to a large number of light receiving elements, and it is therefore necessary to use a light emitting element with a large radiation angle. Therefore, the amount of light received by each light emitting element is small, which limits the position detection ability (detection area, detection resolution, and reliability).

Means for Solving the Problems> In order to solve the problems as described above, the present invention provides a means for solving the above-mentioned problems when there is a light-shielding object having a light-shielding property within the detection area.
The position detection device detects the position of the light-blocking object, and includes scanning means using a rotating mirror disposed at a predetermined position on the circumferential surface of a detection area that sequentially deflects and scans light emitted from one light source. , a first light-shielding phenomenon caused by projecting the light scanned by the scanning means onto a light-shielding object via a reflection means disposed at a predetermined position on the circumferential surface of the detection area; As a light-receiving means for detecting a second light-shielding phenomenon caused by directly projecting light onto the light-shielding object, light-receiving elements are disposed at a predetermined interval on a peripheral surface of the detection area so as to face and diagonally face the reflection means. and a detection means for detecting the position of the light-blocking object based on signals corresponding to the first and second light-blocking phenomena detected by the light-receiving means. The present invention provides a position detection device.

<Operation> The object position detection device as described above scans the light beam scanned by a scanning means using a rotating mirror that sequentially deflects and scans the light emitted from one light source, onto the peripheral surface of the detection area. Detecting a first light shielding phenomenon caused by projecting the light onto a light shielding object through a reflection means disposed at a predetermined position and a light beam scanned by the scanning means, and facing and diagonally facing the reflection means. Detection is performed by computationally processing signals corresponding to the first and second light shielding phenomena detected by a light receiving means in which a plurality of light receiving elements are arranged at predetermined intervals on the circumferential surface of the detection area. The position of a light-blocking object within the area can be detected.

<Example> FIG. 1 shows an example of the object position detection device of the present invention, in which 1 is a detection area of a light-blocking object, 2 is a collimating lens on which light is projected from a light emitting element LD, and 3 is a collimating lens. A rotating mirror having a mirror surface 3a onto which the transmitted light beam L is projected; M is a motor that rotates this rotating mirror and is equipped with a rotating pulse generator; 4 is a reflecting means disposed on the peripheral surface of the detection area 1; A fixed reflector, 5 is the detection area 1
A light-shielding object inside, PD3, is a light-receiving element group in which a plurality of light-receiving elements are arranged at predetermined intervals on the circumferential surface of the detection area 1 so as to face the reflecting mirror 4, and PD4 is located diagonally to the reflecting mirror 4. This is a light-receiving element group in which a plurality of light-receiving elements are arranged at a predetermined interval on the circumferential surface of the detection area 1 so as to face each other.

The light emitted from the light emitting element LD is collimated by the collimator lens 2, and then rotated in a predetermined direction (in the example, in the direction of the arrow) by a motor M disposed at a predetermined position on the circumferential surface of the detection area 1. While the rotating mirror 3 receives the light beam L, the light beam L is sequentially scanned in the rectangular detection area 1 by the rotating mirror 3.

The optical path of the light beam L scanned by the rotating mirror 3 can be roughly divided into three types depending on the rotation angle of the rotating mirror 3.

That is, the light beam L following the first optical path is reflected by a reflecting mirror 4 disposed at a predetermined position on the circumferential surface of the detection area 1, and is projected onto the light receiving element group PD3.

The light beam L2 following the second optical path is reflected by the reflecting mirror 4 similarly to the light beam L1 and is projected onto the light receiving element group PD4.

The light beam L3 following the third optical path is directly projected onto the photodetector group PD4.

The light receiving element groups PD3 and PD4 receive the light beam L.
1 to L3 are being projected, the light receiving element group PD3,
They are arranged at predetermined positions on the circumferential surface of the detection area l at arbitrary numbers and angles so that the phase signal of the PD 4 is outputted continuously to the output terminal 6 without interruption.

When a light-blocking object 5 exists within the rectangular detection area 1, the light beam 1 that has been scanned by the rotating mirror 3 and projected onto the light receiving element PD3n of the light receiving element group PD3
is blocked by this light-blocking object 5, and the sum signal output to the output terminals 6 of the photodetector groups PD3 and PD4 decreases (first light-blocking phenomenon).

On the other hand, while the scanning of the light beam is progressing sequentially by the rotating mirror 3, the light receiving element PD4n of the light receiving element group PD4 is
The light beam L3 that was being projected is also blocked with a time difference from the light beam 1, and the phase signal output to the output terminal 6 decreases in the same way as the first light blocking phenomenon (second blocking phenomenon).

The position of the light-blocking object 5 within the detection area 1 can be detected by processing the signals output from the output terminal 6 corresponding to the first and second light-blocking phenomena as described above.

Furthermore, the principle of determining the positional coordinates of the light-shielding object 5 will be explained using FIG. 2. In FIG. 2, Pl is the scanning base point of the rotating mirror 3 that scans the light beam L, P2 is the virtual image point of the scanning base point P1 created by the reflecting mirror 4, P3 is the position where the light blocking object 5 is present, and SL is a reference line connecting the scanning base point P1 and the virtual image point P2.

When a light-shielding object 5 exists at a position P3 in the rectangular detection area l, the reference position of the rotating pulse generator of the motor M is set on the reference line SL, and the rotating mirror 3 scans toward the reflecting mirror 4. When the light beam L1 reflected by the reflecting mirror 4 is projected onto the light-shielding object 5, the light receiving element PD3
The light incident on n is blocked, and the phase signals of the light receiving element groups PD3 and PD4 obtained at the output terminal 6 of the sum signal decrease (first light blocking phenomenon). For example, the angle between the reference line SL (which outputs one pulse signal per rotation) and the light beam L1 is θ1. L1
゛ is virtual image light with respect to the light beam L1, and this virtual image light L
The angle θ1' between L' and the reference line SL is equivalent to the angle θ1.

On the other hand, when the light beam L3, which has been sequentially scanned by the rotating mirror 3, is directly projected onto the light-blocking object 5, the light incident on the light-receiving element PD4n is blocked, and the light-receiving element groups PD3 and PD4 are again The sum signal decreases (second shading phenomenon).

Reference line SL of the rotating pulse generator and light beam L3 at that time
If the angle between the
The coordinates (x, y) of the scanning base point P1. Assuming a triangle connecting the position P3 of the light-blocking object 5 and the virtual image point P2, with the reference line SL as the axis and the scanning base point P1 as the locus origin, one side and two corners touching this side in the triangle, that is, Distance a from scanning base point P1 to virtual image point P2 and angles θ1' (θ1), θ2
It is determined by the following formula.

Therefore, how to obtain the angles θ1 and θ2 will be explained with reference to FIGS. 3 to 5. In FIG. 4, 6 indicates each light receiving element group P.
D3. 7 is a rotation pulse generator provided in the motor M; 8 is a gate circuit; 9 is a phase signal output terminal of PD 4;
is an amplifier circuit, 1o is a waveform shaping circuit, 11 is an inverter,
12 is a multi-by-break circuit, and 13 is an arithmetic circuit.

FIG. 3 shows the output signal waveforms of each of the circuits described above, and FIG. 5 shows details of the gate circuit 8.

The rotational pulse output as shown in FIG. 3(A) outputted from the rotational pulse generator 7 provided in the motor M is
By entering the analog switch 14 of the gate circuit 8 configured as shown in the figure, the current from the power supply 15 flows through the diode 16 and charges the capacitor 17.
A gate signal as shown in FIG. 3(E) is obtained and reaches the gate terminal 19.

On the other hand, the photodetector group PD3. The sum signal of PD4 is amplified by an amplifier. This amplified signal (B) is converted into a shaped pulse signal as shown in (C) in FIG. 3 by the waveform shaping circuit 10, and is converted into an inverted signal as shown in (D> in FIG. 3) by the inverter 11. The pulse signals 11-1 and 11-2 of the inverted signal <D) are signals corresponding to the first and second light shielding phenomena. And this inverted signal (D)
When the pulse signal 11-1 enters the analog switch 18 of the gate circuit 8, the charge stored in the capacitor 17 is discharged, and the gate output signal becomes zero as shown in FIG. 3(E).

At the same time that the pulse signal 11-1 of the inverted signal (D) enters the gate circuit 8, the multivibrator circuit 12 also outputs a signal as shown in (F) in FIG.
It stops when the pulse signal 11-2 of D> is output. In other words, the gate output signal (E) output from the gate circuit 8 is the time required for the first light shielding phenomenon to occur after the rotation pulse output signal (A) is output.
Gate output signal (E) and multi-by-break circuit 1
The sum of the two output signals (F) is the time required for the second light shielding phenomenon to occur. During the above two times, the arithmetic circuit 13
Angle θ1 in the figure. It can be determined as the angle of the rotating mirror 3 corresponding to θ2 (this angle corresponds to half of θ1° and θ2, respectively).

<Effects of the Invention> As explained above, the present invention converts the light emitted from one light emitting element into parallel light and sequentially scans the detection area using a rotating mirror, so there is little change in the received light intensity. , it is possible to configure an object position detection device in which the number of light emitting elements and light receiving elements is reduced.

[Brief explanation of the drawing]

1 is a configuration diagram of the object position detection device of the present invention, FIG. 2 is an explanatory diagram of object position detection in this object position detection device, FIG. 3 is a timing chart of each signal of the detection circuit, and FIG. 4 is a block diagram of a detection circuit, FIG. 5 is a block diagram of a gate circuit, and FIG. 6 is an example of a conventional object position detection device.LD...Light emitting element, PD3, PD4...Light receiving element Group, PD3n, PD4n-light receiving element, M-...motor, 1
...Detection area, 2...Collimating lens, 3-...
rotating mirror, 3a...mirror surface, 4...reflecting mirror, 5...light-shielding object, 6--output terminal for phase signal of light-receiving element group;

Claims (1)

[Claims] A position detection device that detects the position of a light-blocking object when a light-blocking object exists in a detection area,
A scanning means using a rotating mirror disposed at a predetermined position on the circumferential surface of the detection area to sequentially deflect and scan the light emitted from one light source; A first light-shielding phenomenon occurs when the light is projected onto a light-shielding object via a reflecting means arranged at a predetermined position of the light-shielding object, and a second light-shielding phenomenon occurs when the light scanned by the scanning means is directly projected onto the light-shielding object. As a light receiving means for detecting light blocking phenomena,
A plurality of light receiving elements are disposed at predetermined intervals on the peripheral surface of the detection area so as to face and diagonally face the reflecting means, and the first and second light blocking phenomena detected by the light receiving means are An object position detection device comprising: a detection means for detecting the position of the light-blocking object based on a corresponding signal.