JPS63157003A - Position detecting device for body - Google Patents

Abstract

PURPOSE:To simplify the constitution of the whole detecting device by deflecting and scanning light emitted by a light source successively by a scanning means. CONSTITUTION:The light emitted by the light emitting element LD is collimated by a collimator lens 1 into parallel light, which is projected on mirror surfaces 2' of a rotary mirror 2 which is driven by a motor M to rotate in a specific direction. While this mirror 2 photodetects the light beam L, the beam L is scanned sequentially in a rectangular detection area 4. Then a light beam L1 in the optical path of the beam L is reflected by the reflecting mirror 3, projected on a light guide LG1, and incident on a photodetecting element PD1. A light beam L2, on the other hand, is reflected by the mirror 3 and incident directly on a photodetecting element PD2, and a light beam L3 is also reflected by the mirror 3, projected on a light guide LG2, and incident on the element PD2. Further, a light beam L4 is projected directly on the light guide LG2 and incident on the element PD2. Then those photodetecting elements processes signals corresponding to a detected light shield phenomenon to detect the position of a light shielding body.

Description

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

<Prior Art> As an example of a conventional light-blocking object position detection device, a rectangular detectability I421 shown in FIG. 10 has a large number of light-receiving element names 106. A light emitting device LDI is arranged at each of the four corners of the rectangular detection area 21.

LD2. LD3. LD4 is arranged, and the light emitting elements LD1. L
The diffused light from D2 is configured so that all of the light receiving element group PD7 arranged facing the light emitting elements LO1 and LD2 receive the light, and the light emitting elements LD3.1D4
The light receiving element group PD6 is configured so that all of the light receiving element groups PD6 can receive the diffused light, and when a light-blocking object exists within the rectangular detection area 21, a light-blocking phenomenon occurs depending on the position of the light-blocking object. A system has been put into practical use in which the position of a light-blocking object is detected based on the position of each light-receiving element in a group of light-receiving elements.

<Problems to be Solved by the Invention> Although the position detection device for a light-blocking object according to the above-mentioned prior art has considerably fewer light-emitting elements than before, 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. For this reason, the amount of light received by each light-receiving 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 above-mentioned problems, the present invention provides a position detection 9i that detects the position of a light-blocking object when the object exists within the detection area. a scanning means for sequentially deflecting and scanning the light emitted from the light source; a first light blocking phenomenon caused by projecting the light scanned by the scanning means onto a light blocking object via a reflecting means; a light-receiving means for detecting a second light-shielding phenomenon caused by directly projecting the light scanned by the scanning means onto the light-shielding object; The present invention provides an object position detection device including a detection means for detecting the position of the light blocking object based on a signal corresponding to a second light blocking phenomenon.

Effect> A first light shielding phenomenon caused by the object position detecting device as described above causes the light scanned by the scanning means to be projected onto the light shielding object via the reflecting means; and a second light-blocking phenomenon caused by directly projecting the scanned light onto the light-blocking object, by calculating and processing signals corresponding to the first and second light-blocking developments detected by the light receiving means. , the position of the light blocking object can be detected.

<Example> FIG. 1 shows an example of the object position detection device of the present invention.
LD is a light emitting element, 1 is a collimating lens, 2 is a rotating mirror,
2' is the mirror surface of a rotating mirror, M is a motor equipped with a rotating pulse generator, is a light beam, 3 is a fixed anti-114 mirror,
Reference numeral 4 indicates a detection area for a light-blocking object, PO1 and PO2 are light receiving elements, and LG1 and LG2 are light guides that are light guiding members.

After the light emitted from the light emitting element LD is made into parallel light by the collimating lens 1, the light is turned into parallel light by a motor M provided at a predetermined position.
The light beam L is projected onto the mirror surface 2' of the rotating mirror 2 which is rotationally driven in a predetermined direction (counterclockwise in the embodiment), and while the rotating mirror 2 receives the light beam L, the light beam L has a rectangular shape. The detection area 4 is sequentially scanned.

The optical path of the light beam L scanned by the rotating mirror 2 can be roughly divided into four types depending on the rotation angle of the rotating mirror 2.

The light beam L1 following the first optical path is reflected by the reflection IJI3 disposed at a predetermined position, and is reflected by the light guide LG1.
is projected on. This light guide LG1, as shown in FIG.
-1' to a predetermined light-receiving element PDI, the light beam L1' projected onto the light guide LG1 in FIG. The light is incident on the light receiving element PD1.

The light beam L2 following the second optical path is reflected by the reflecting mirror 3 in the same way as the light beam L1, and directly enters the light receiving element PD2.

The light beam L3 following the third optical path is also the light beam L1. L2
Similarly, it is reflected by reflection vA3 and projected onto light guide LG2. As shown in FIG. 3, this light guide LG2 has minute reflecting surfaces R2 and R3 formed alternately, and a light beam L3' projected onto the light guide LG2.
is reflected by the reflective surface R3 and enters the light receiving element PD2.

The light beam L4 (L4') following the fourth optical path is directly projected onto the light guide LG2, and is directed to the light receiving element PD2 by R2 (FIG. 3).

Next, when a light-blocking object 6 exists in the rectangular detection area 4, the principle of determining the positional coordinates of the light-blocking object 6 will be explained with reference to FIG. In FIG. 4, Pl is the scanning base point of the rotating mirror 2 that scans the light beam L, P2 is the virtual image point of the scanning base point P1 created by the reflection 13, P3 is the position where the light blocking object 6 is present, and 5 is the scanning base point. This is a reference line connecting P1 and virtual image point P2.

When the light-shielding object 6 exists at the position P3 of the rectangular detection area 1114, the reference position of the rotation pulse generator of the motor M is set to the above li! The light beam L5 set on the mirror 15 and scanned toward the anti-tA mirror 3 by the rotation 112 is reflected 1
When reflected at t3 and projected onto the light-blocking object 6, the light that was incident on the light-receiving element PDI via the light guide LGI is blocked, and the light-receiving element P obtained at the sum signal output terminal 7 is blocked.
The sum signal of D1 and PO2 decreases (first shading phenomenon). At that time, the reference line 5 of the rotation pulse generator (for example, outputs one pulse signal per rotation) of the motor M and the light beam L
Let θ1 be the angle formed with 5. L5' is the light beam L5
The angle θ1' between this virtual image light 15' and the reference line 5 is equivalent to the angle θ1.

On the other hand, when the light beam 6 that has been sequentially scanned by the rotating mirror 2 is directly projected onto the light-blocking object 6, the light that was incident on the light-receiving element PD2 via the light guide LG2 is blocked and re-entered. The sum signal of the light receiving elements PD1 and PO2 decreases (second light shielding phenomenon).

If the angle between the reference line 5 of the rotating pulse generator and the light beam beam 6 at that time is θ2, the coordinates (x, y) of the position P3 of the light-shielding object 6 are determined by scanning with the reference line 5 in the figure as the base. Assuming a triangle connecting the reference point P1, the position P3 of the light-blocking object 6, and the virtual image point P2, and taking the filler line 5 as the axis,
When the scanning base point P1 is taken as the coordinate origin, one side and the two corners touching this side in the triangle mentioned above, that is, the distance a and the angle θ1' (θ1〉, θ) from the scanning base point P1 to the virtual image point P2.
2, it can be found by the following formula.

Therefore, the angle θ1. How to obtain θ2 will be explained with reference to FIGS. 5 to 7. In FIG. 6, reference numeral 7 indicates a phase signal output terminal A of each light-receiving element, 8 indicates a rotating pulse generator provided in the motor M, 9 indicates a gate circuit, 10 indicates an amplifier circuit, 11 indicates a waveform shaping circuit, and 12 indicates a 13 is a multivibrator circuit, and 14 is an arithmetic circuit.

FIG. 5 shows the output signals of each of the circuits described above, and FIG. 7 shows details of the gate circuit 9.

The rotational pulse output as shown in FIG. 5(A) outputted from the rotational pulse generator 8 provided in the motor M is
By entering the analog switch 15 of the gate circuit 9 configured as shown in the figure, the current from the power supply 16 flows through the diode 17 and charges the condenser 18, so that the gate signal @ (E) (see Figure 5) is 19 and gate terminal 20
reach.

On the other hand, the photodetector PD1. The sum signal of PD2 is amplified by an amplifier 10. This amplified signal ([3) becomes a shaped pulse signal (C) (see FIG. 5) by the waveform shaping circuit 11, and becomes an inverted signal (D>) by the inverter 12. The pulse signal 12 of this inverted signal (D) -1.12-2
are signals corresponding to the first and second light shielding phenomena described above. Then, when the pulse signal 12-1 of the inverted signal (D) enters the analog switch 19 of the gate circuit 9, the electric charge charged in the capacitor 18 drops, and the gate signal (E) becomes zero.

At the same time that the pulse signal 12-1 of the inverted signal (D) enters the gate circuit 9, the signal @F is also output from the multivibrator circuit 13, and the pulse signal 12-2 of the inverted signal is output, thereby stopping the signal. do. In other words, this gate output (E) is the time required for the first light blocking phenomenon to occur after the rotation pulse signal (A) is output, and the sum of the gate output E and the output (F) of the multivibrator circuit 13 is This is the time required for the second light blocking phenomenon to occur. The above two times are the paralysis circuit 14, and the angle θ1. The angle of the rotating mirror 2 corresponding to θ2 (however, this angle is G1°G2
(equivalent to half of each).

FIGS. 8 and 9 are modified examples in the case where the configuration example of FIG. 1 cannot be used due to changes in the detection area or the like. Figure 8 shows the light guide in Figure 3 with reflective surfaces R2 and R like G2.
3 (light beams L3' and 14' with considerably different scanning angles)
If it is not possible to form a reflective surface (formed on the same plane) for guiding the light to a predetermined light receiving element PD2, the reflective surface R
2. Light guide LG2-1 as if R3 were formed separately. This is an example in which the LG2-2 is arranged in a direction perpendicular to the plane of the paper in FIG. 3, and light beams with extremely different scanning angles are guided to the light receiving element.

In FIG. 9, LG3. LG4. LG5 is a light guide, and PO2, PO2, PO2-1° PO2-2 is a light receiving element. Fig. 9 shows a case where the detection area 4 expands in the configuration example shown in Fig. 1 and the reflectance of the light guide LG1. This is an example of increasing the number of light guides and light receiving elements to maintain light receiving efficiency (the area of the reflecting surface of the light guide becomes smaller).

<Effects of the Invention> As explained above, in the present invention, since the light emitted from one light emitting element is converted into parallel light and scanned, there is little change in the light intensity no matter where the light is received. Therefore, one light guide and light receiving element can receive scanned light over a wide range, so that not only the number of light emitting elements and light receiving elements but also the configuration of the entire detection device can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an object position detection device according to the present invention;
3 and 3 are detailed diagrams of the light guide, which is a light guide member, FIG. 4 is an explanatory diagram of object position detection, FIG. 5 is a timing chart of each signal of the detection circuit, and FIG. 6 is a diagram of the detection circuit.
Figure 7 is a block diagram of the gate circuit, Figure 8 is a diagram showing a modification of the light guide, Figure 9 is a diagram showing a modification of this position detection device, and Figure 10 is a diagram showing a modification of the conventional position detection device. This is an example of an object position detection device. LD...Light emitting element, PDl, PO2, PO2゜PO2
, PO2-1, PO2-2...light receiving element, LGl, L
G2...Light guide as a light guide member, M...Motor, 1...Collimating lens, 2... Rotating mirror, 2'
... Mirror surface of rotating mirror, 3... Reflecting mirror, 4... Detection area, 6... Light blocking object. Patent Applicant: Victor Japan Co., Ltd. Agent: Yuki Omata
Tomonosuke Araki Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 - Figure 9 Figure 10

Claims (4)

[Claims] (1) A position detection device that detects the position of a light-blocking object when the object exists within the detection area,
a scanning means that sequentially deflects and scans the light emitted from the light source;
A first light blocking phenomenon occurs when the light scanned by the scanning means is projected onto the light blocking object via the reflecting means, and a first light blocking phenomenon occurs when the light scanned by the scanning means is directly projected onto the light blocking object. and a detection means that detects the position of the light-blocking object based on signals corresponding to the first and second light-blocking phenomena detected by the light-receiving unit. A device for detecting the position of an object. (2) The object position detecting device according to claim 1, wherein the scanning means is a rotating mirror. (3) As a light receiving means for receiving the light scanned by the scanning means and detecting a light blocking phenomenon caused by a light blocking object,
An object position detecting device according to claim 1, comprising one or more light receiving elements and one or more light guiding members that guide and receive light to the light receiving elements. (4) A patent in which the detection means for detecting the position of the light-blocking object is configured such that a calculation circuit calculates the position coordinates of the object based on the signal corresponding to the light-blocking phenomenon detected by the light-receiving means and the rotational position of the rotating mirror. An object position detection device according to claim 1.