JP2000298017A - Multi-beam photoelectric sensor and method for mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive multi-beam photoelectric sensor the size of which is reduced to a relatively small size while the sensor is enabled to detect a wide range of objects in a plurality of directions even when the objects move by forming light beams in a plurality of directions. SOLUTION: A multi-beam photoelectric sensor forms a plurality of light beams by passing light rays from a plurality of light emitting elements 11a-11c through a light emitting optical system 12. The sensor converges the light spots formed on objects 3a-3c when the objects 3a-3c are respectively irradiated with the light beams on the light receiving surface of a light receiving element 21 through a light receiving optical system 22 and finds the distances to the objects 3a-3c based on the output of the element 21. The light emitting elements 11a-11c are arranged perpendicularly to the moving directions of the received light spots and also to the optical axis of the light receiving optical system 22 in accordance with the distances to the objects 3a-3c. In addition, the width of the light receiving surface of the light receiving element 21 is set to such a size or larger that the received light spots can be formed on the light receiving surface correspondingly to all light beams.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a light spot on an object by irradiating the object with a light beam, and for changing the line of sight of the light spot from the light receiving element through a light receiving optical system to the output of the light receiving element. More particularly, the present invention relates to a multi-beam photoelectric sensor that obtains a distance to an object based on the line-of-sight direction using the principle of baseline length triangulation and a mounting method thereof.

[0002]

2. Description of the Related Art A distance measuring photoelectric sensor having a configuration shown in FIG. 9 has been known. This photoelectric sensor forms a light spot on the object 3 by irradiating the object (including a person) 3 with a light beam from the light projecting means 1 and the light receiving means 2
Object 3 based on the line-of-sight direction when seeing a light spot from
In addition to generating a distance signal corresponding to the distance up to, the magnitude of a distance signal and a threshold value defining the distance are compared to detect the presence or absence of the object 3 in a predetermined distance range.

The light projecting means 1 includes a light projecting element 11 using a light emitting diode or a laser diode, and generates a light beam by passing a light output of the light projecting element 11 through a light projecting optical system 12. Here, a light emitting diode is used. The light projecting element 11 emits light intermittently at a period defined by the output of the oscillation circuit 10 given through the drive circuit 13.

On the other hand, the light receiving means 2 includes a light receiving element 21 capable of obtaining an output corresponding to the position of the center of gravity of the light quantity distribution on the light receiving surface. As the light receiving element 21, a PSD, a photodiode array, a two-division photodiode, or the like can be used. A light receiving optical system 22 for converging a light beam is disposed in front of the light receiving surface of the light receiving element 21, and receives a light spot formed on the object 3 by irradiation of a light beam from the light projecting means 1 through the light receiving optical system 22. The light is converged on the light receiving surface of the element 21. The line-of-sight direction in which the light spot is viewed from the light receiving element 21 through the center of the light receiving optical system 22 changes according to the distance to the object 3 in the light beam irradiation direction as shown in FIG. Since the light receiving optical system 22 converges the light spot on the light receiving surface of the light receiving element 21, the position of the center of gravity of the light amount distribution on the light receiving surface of the light receiving element 21 (hereinafter referred to as the light receiving spot) changes according to the change in the line-of-sight direction. Will be. That is, the position of the light receiving spot on the light receiving surface of the light receiving element 21 changes according to the distance to the object 3.

Here, it is assumed that a two-division photodiode is used as the light receiving element 21. This light receiving element 21 has two photodiodes 21a, 2a as shown in FIG.
1b are arranged side by side, and the ratio changes according to the position of the light receiving spot on the light receiving surface (the vertical axis in FIG. 10 indicates the light receiving amount, and the center of the light amount distribution becomes the light receiving spot).
It is configured to obtain two current outputs. The direction in which the photodiodes 21a and 21b are arranged may be any direction as long as the movement of the light receiving spot according to the distance to the object 3 can be detected, and is usually a plane including the optical axis of the light projecting optical system 12 and the light receiving optical system 22. And in a direction perpendicular to the optical axis of the light receiving optical system.

Now, it is assumed that the optical axes of the light projecting optical system 12 and the light receiving optical system 22 are parallel, and the center of the light projecting optical system 12 and the center of the light receiving optical system 22 are located on the same plane. .
The distance between the centers of the light projecting optical system 12 and the light receiving optical system 22 is defined as a base length BL, and the plane including the center of the light projecting optical system 12 and the center of the light receiving optical system 22 and the light receiving surface of the light receiving element 21 It is assumed that they are arranged in parallel at a distance S.
Further, the distance from the center of the light projecting optical system 12 to the center of the light receiving surface of the light receiving element 21 in the direction connecting the center of the light projecting optical system 12 and the center of the light receiving optical system 22 is BLD. Assuming that the distance from the center of the light projecting optical system 12 to the object 3 when the light receiving spot is formed at the center of the light receiving surface of the light receiving element 21 is L, the relationship BL: L = (BLD-BL): S is obtained. From this state, when the object 3 comes closer by the distance ΔL, the position of the light receiving spot on the light receiving surface of the light receiving element 21 becomes Δ
If it moves by x, BL: (L−ΔL) = (BL
D−BL + Δx): S is obtained. Therefore, when ΔL is represented using Δx, ΔL = ΔxL / (BL
D−BL−Δx).

On the other hand, as shown in FIG. 10, it is assumed that the current output from the light receiving element 21 is i1, i2, and the current i1 increases when the object 3 approaches, and the light receiving spot in the direction to increase the current i1 If the moving direction of is x direction,
It is known that Δx = k · (i1-i2) where k is a proportional constant. Therefore, the distance to the object 3 is L
Is the reference position, and the displacement from the reference position is ΔL.
Then, ΔL becomes a function of (i1-i2), and the displacement Δ
If L is on the short distance side, the difference (i
1-i2) increases.

By using the above relationship, the object 3 is determined based on the currents i1 and i2 output from the light receiving element 21.
You can know the distance to. Since the output of the light receiving element 21 is the current i1, i2, the current-voltage converters 23a, 23
3b, voltages V1, V2 proportional to currents i1, i2
The difference (V1−V2) between the two voltages V1 and V2 is obtained by the subtractor 24. Since the voltage difference (V1-V2) is proportional to the current difference (i1-i2), the displacement ΔL is a function of the voltage difference (V1-V2). Therefore, when the voltage difference (V1-V2) is compared with the threshold value in the comparator 25 using the reference voltage output from the reference voltage generation circuit 26 as a threshold value, the distance to the object 3 is determined to be within the specified distance range. Can be determined. Here, when the object 3 exists within the reference distance (set distance) L, the comparator 2
The threshold value is set so that the output of No. 5 becomes L level. That is, if the threshold is Vth, V1−V2 ≧
The comparator 25 is configured so that the output of the comparator 25 becomes L level at Vth. In the above example, the light receiving element 2
Since i1 ≒ i2 when a light receiving spot is formed near the center of the light receiving surface of No. 1, if it is detected that the object 3 exists within the distance range up to the reference distance L, the threshold value Vth is It may be set to almost 0.

The output of the comparator 25 is taken out through an output circuit 27. Here, since the light emitting element 11 emits light intermittently due to the output of the oscillation circuit 10, the output of the light receiving element 21 other than the light emitting period of the light emitting element 11 becomes noise. Therefore, in the output circuit 27, the oscillation circuit 10
The output of the comparator 25 is taken out in synchronization with the light emission period of the light projecting element 11 using the output of (1). In the above configuration, the current-voltage conversion circuits 23a and 23b, the subtractor 24, and the comparator 2
5. The calculation means is constituted by the reference voltage generation circuit 26 and the output circuit 27.

As described above, if the object 3 exists within the reference distance L, the output becomes L level. Therefore, if the reference distance L is set appropriately, it is determined whether the object 3 exists within the reference distance L. Can be obtained. In order to change the reference distance L, the arrangement of each member may be changed so as to change the base line length BL, the distance BLD, or the distance S, or the threshold value Vth provided to the comparator 25 may be changed.

[0011]

In a distance-measuring type photoelectric sensor that determines the presence or absence of the object 3 based on the distance to the object 3 as in the above-described photoelectric sensor, a light beam is applied to the object 3. The distance can be measured only in a narrow range where the light beam is irradiated. In the case of an object 3 having irregularities, the measured distance differs depending on which part of the object 3 is irradiated with the light beam. , It is difficult to accurately determine the distance to the object 3 with good reproducibility. In addition, in the above-described example, since the irradiation direction of the light beam is fixed, it is impossible to determine the distance to the object 3 or the distance to the moving object 3 in a plurality of directions.

In order to solve this kind of problem, it is conceivable to provide a plurality of sets of the light projecting means 1 and the light receiving means 2 in one body, but if such a configuration is adopted, the body becomes large. In addition, compared with the case where a plurality of sets of the light projecting means 1 and the light receiving means 2 are simply provided, there is a problem that the cost is increased by the amount of the body.

Instead of providing a plurality of sets of the light projecting means 1 and the light receiving means 2, it is conceivable to provide a plurality of sets of the light projecting elements 11 and the light receiving elements 21 and share a circuit portion. Relative position relationship between each pair of the light emitting element 11 and the light receiving element 21 (in short, the light emitting element 11 and the light receiving element 12
Are required to be arranged so as to be equal to each other, and a high accuracy is required for mounting the plural sets of the light projecting element 11 and the light receiving element 21, and the cost is increased due to precision management. Occurs.

This configuration is disclosed in Japanese Patent Laid-Open No. 9-274839.
Japanese Patent Application Laid-Open Publication No. H11-157210 discloses an arrangement in which a light projecting means is a multi-beam light source and a plurality of light receiving elements sharing a light receiving optical system are arranged as light receiving means. However, the distance range for judging the presence or absence of an object is mainly determined by the position of the light receiving element, as is clear from the above description of the principle. Therefore, when a plurality of light receiving elements are arranged as described in the above publication, The distance range has to be adjusted for each light receiving element, which results in high cost due to accuracy control.

The present invention has been made in view of the above circumstances, and has as its object to form a light beam in a plurality of directions to detect an object in a wide range or to detect an object in a plurality of directions. Another object of the present invention is to provide a relatively small and low-cost multi-beam photoelectric sensor that can detect a moving or moving object. An object of the present invention is to provide a mounting method of a multi-beam photoelectric sensor that can be combined.

[0016]

According to a first aspect of the present invention, there is provided a light projecting means having a plurality of light projecting elements and forming a plurality of light beams from each of the light projecting elements through a light rain projection optical system. A light receiving means for forming a light receiving spot by converging a light spot formed on the object when each light beam is irradiated on the object through a light receiving optical system to a light receiving surface of a light receiving element, and receiving light according to the position of the light receiving spot Calculating means for determining the presence or absence of an object within a set distance range based on the output value of the element, and projecting the light on one straight line in a plane orthogonal to the direction in which the light receiving spot moves in accordance with the distance to the object. The optical elements are arranged, and the width dimension of the light receiving element in the direction in which the light projecting elements are arranged is set to be equal to or larger than a dimension capable of forming a light receiving spot on the light receiving surface corresponding to all light beams.

According to a second aspect of the present invention, in the first aspect of the present invention, the light emitting means causes each light emitting element to emit light alternatively.

According to a third aspect of the present invention, in the first aspect of the present invention, the light emitting means selectively emits light from each of the light emitting elements, and the arithmetic means determines a light emitting period of each light emitting element. It is provided with a decoder that separates and outputs the different outputs.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the light projecting means scans the light beam by causing each of the light projecting elements to emit light cyclically, and the arithmetic means comprises: A decoder that separates the determination results of the light emission periods and extracts them as different outputs, and a data latch that temporarily holds at least outputs corresponding to a plurality of both ends at the scanning range of the light beam among the outputs of the decoders,
And two AND circuits for respectively outputting the logical product of the judgment results held by the data latch corresponding to each of a plurality of lines at both ends in the scanning range of the light beam.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, a substrate on which each of the light emitting elements and the light receiving elements is mounted is provided, and each of the light emitting elements and the light receiving elements is housed and projected. Providing a pair of grooves on the substrate, one side edge of which is parallel to the direction in which the optical elements are arranged,
The light emitting element and the light receiving element are fixed in the grooves in such a manner that they are in contact with the one side edges of the respective grooves.

According to a sixth aspect of the present invention, there is provided the mounting method of the multi-beam photoelectric sensor according to the fifth aspect, wherein the light projecting element and the light receiving element are brought into contact with the one side edge of the groove by tilting the substrate. The light-emitting element and the light-receiving element are mounted on the substrate in a state where they are in contact with each other.

According to a seventh aspect of the present invention, in the first to fourth aspects of the present invention, a substrate on which each of the light emitting element and the light receiving element is mounted is provided, and the light emitting element and the light receiving element and one of the substrates are convex. A concave portion for positioning the light emitting element and the light receiving element on the substrate by engaging with the convex portion.

According to an eighth aspect of the present invention, in the first to fourth aspects of the present invention, a substrate on which each of the light emitting elements and the light receiving elements is mounted is provided, and each of the light emitting elements and the light receiving elements is flip-chip mounted on the substrate. Is what is being done.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) In this embodiment, as shown in FIG. 1A, a light projecting means 1 having a structure capable of projecting a plurality of light beams is used. The light receiving element 21 used for the light receiving means 2 is an object 3a to 3c
Is characterized in that it has a long light receiving surface in a direction orthogonal to the direction in which the light receiving spot moves in accordance with the distance of.

This will be described more specifically. In the illustrated example, the light projecting means 1 includes three light projecting elements 11a, 11b, and 11c each composed of a light emitting diode array.
“c” forms light beams in mutually different directions using the light projection optical system 12 in common. However, the three light beams are formed so as to be included in the same plane. In other words,
The light projecting elements 11a to 11c are arranged on a straight line (this direction is defined as the y direction).

On the other hand, the light receiving means 2 uses, as the light receiving element 21, a two-division photodiode in which two photodiodes are arranged in a direction orthogonal to a plane including the three light beams described above (hereinafter referred to as an x direction). ing. The light receiving surface of the light receiving element 21 is arranged so as to be orthogonal to the optical axis of the light receiving optical system 22 as in the conventional configuration. Also, the light receiving element 21
The light receiving surface is longer than the conventional light receiving element 21 in the direction (y direction) parallel to the plane including the three light beams described above. That is, when the three light beams are applied to the objects 3a to 3c within the target distance range, the light receiving spots corresponding to the light spots formed on all the objects 3a to 3c are formed on the light receiving surface. The size and position of the light receiving surface of the light receiving element 21 in the y direction are set.

In the present embodiment, the base line length BL explaining the principle is the same as the center of the light projecting optical system 12 and the light receiving optical system 22.
In this embodiment, the distance BLD is the distance between the straight line on which the light projecting elements 11a to 11c are arranged and the center of the light receiving element 21 in the x direction. With this relationship, it can be handled in the same manner as when only one light emitting element is used.

That is, the light projecting elements 11a to 11c and the light receiving element 21 are connected to a circuit constituting a calculating means as shown in FIG. Each of the light emitting elements 11a to 11c is selectively selected by a changeover switch SW1, and three light emitting elements 1a to 11c are selected.
1a to 11c emit light cyclically. That is, the light beam is scanned in one direction. The changeover switch SW1 is controlled by the changeover circuit 14, and the changeover circuit 14 operates based on the drive signal generated by the drive circuit 13 based on the output of the oscillation circuit 10. Here, the light output from each of the light projecting elements 11 a to 11 c is modulated by the output frequency of the oscillation circuit 10. The oscillation circuit 10 has a selection switch S
It is possible to select whether or not to receive an external trigger by turning on and off W2. When the state of receiving an external trigger is selected, the oscillation circuit 10 operates only when a trigger signal is input from outside. The oscillation circuit 10 controls a power supply circuit 28 for supplying power to a circuit that processes an output signal of the light receiving element 21.

The output of the light receiving element 21 is processed in the same manner as in the conventional configuration. That is, the two output signals of the light receiving element 21 which are current outputs are input to the current / voltage converters 23a and 23b, respectively, and are converted into voltage values. Then, the two current-voltage converters 2
The outputs of 3a and 23b are input to a differential amplifier as a subtractor 24, and a voltage difference corresponding to a current difference between two outputs of the light receiving element 21 is obtained. As described above, the light emitting elements 11a to 11
Since c is modulated by the output from the oscillation circuit 10, the output of the subtractor 24 is an alternating current. Therefore, the DC component is removed from the output of the subtracter 24 by the capacitor C, and amplification is performed by the AC amplifier 29. The output of the AC amplifier 29 is input to the comparator 25 and is compared with a reference voltage output from the reference voltage generation circuit 26 as a threshold.

Here, among the currents i1 and i2 (see FIG. 10) output from the light receiving element 21, the objects 3a to 3c
It is assumed that the current i1 increases on the short distance side from the reference distance L, and the voltage difference corresponding to i1-i2 is obtained in the subtractor 24. It is also assumed that the output of the comparator 25 is set to the H level when the output voltage of the AC amplifier 29 becomes lower than the reference voltage output from the reference voltage generation circuit 26.

Under this condition, when the objects 3a to 3c are located farther than the reference distance L, the output of the subtractor 24 becomes negative, and the output of the comparator 25 becomes H level with respect to this output. If the reference voltage output from the reference voltage generation circuit 26 is set, the comparator 25 determines whether the objects 3a to 3c are located farther or shorter than the reference distance L.
Can be known by the output of Other configurations and operations are the same as those of the conventional configuration.

In the configuration of this embodiment, the light emitting element 11a
11c are caused to emit light cyclically because the light receiving element 21
If a plurality of light receiving spots are formed on the light receiving surface, the position of the center of gravity of the light receiving spot cannot reflect the distance between the individual objects 3a to 3c. Further, since the output of the comparator 25 treats the individual light beams without discrimination, when the object 3a to 3c exists within the reference distance L with respect to any of the detection beams, The output goes low. That is, each of the objects 3a is formed by using three light beams.
As a result, an output corresponding to the logical sum of the results of determining the distances up to 3c is obtained. In other words, the objects 3a to 3a are formed in a relatively wide range formed by the three light beams.
It is possible to determine whether 3c is within a predetermined distance range.

In the configuration shown in FIG. 1B, the outputs of the current / voltage converters 23a and 23b are input to the subtractor 24.
The subtracter 24 may be used after the outputs of the current-voltage converters 23a and 23b are logarithmically amplified. Here, the output voltages of the current-voltage converters 23a and 23b are V1 and V, respectively.
Assuming that V2 is 2, V1-V2 is obtained in the configuration in which the outputs of the current-voltage converters 23a and 23b are input to the subtractor 24. However, when logarithmic amplification is performed, logV1-logV2 = log
(V1 / V2) will be obtained. This value is also the object 3a
Since the distances from 3a to 3c are reflected, it is possible to determine whether or not the objects 3a to 3c are within the predetermined distance range only by comparing the reference voltage with the comparator 25. Further, if logarithmic amplification is performed, the dynamic range required in the subsequent stage can be reduced. Further, the output logic of the comparator 25 can be reversed. That is, the output of the comparator 25 is set to H for the objects 3a to 3c within the reference distance L.
The level may be set.

In this embodiment, three light emitting elements 11
Although a to 11c are used, the number of light projecting elements is not particularly limited, and the technical idea of the present invention can be applied if there are a plurality of light projecting elements. Further, in the above example, an example in which the light emitting elements 11a to 11c emit light cyclically has been described, but all the light emitting elements 11a to 11c may emit light simultaneously. In this case, the position of the center of gravity of the light receiving spot changes depending on the number of light beams applied to the object 3 even if the distance to the object 3 is equal. Therefore, the distance to the object 3 cannot be known. It is possible to determine whether the object 3 exists within a predetermined distance range. That is, all the light projecting elements 11a to 11c
Are emitted at the same time, the area for detecting the object 3 can be expanded.

(Second Embodiment) In the first embodiment, the output of the comparator 25 is not individually distinguished for a plurality of light beams, but in the present embodiment, the comparator 25 is provided for each light beam. The output of is distinguished and taken out. Therefore, as shown in FIG.
A decoder 30 is provided on the output side of the comparator 25 in order to output the output of the comparator 25 to another path in synchronization with the light emission of 1c. The decoder 30 is controlled by the changeover circuit 14 in synchronization with the changeover switch SW1, and is configured to divide the output of the comparator 25 into three paths. That is, the decoder 3
0 is each light emitting element 1 selected by the changeover switch SW1.
It has a function of outputting the output of the comparator 25 from different terminals during the light emission periods 1a to 11c.

According to this configuration, the judgment result of the comparator 25 corresponding to each light beam can be individually taken out.
It is possible to extract a result of determination as to whether or not the objects 3a to 3c exist within a predetermined distance range for each light beam.
Other configurations and operations are the same as those of the first embodiment.

(Third Embodiment) This embodiment is similar to FIG.
As shown in the figure, a data latch 31a which latches the output of the decoder 30 in the configuration of the second embodiment.
To 31c, and AND circuits 32a and 32b for outputting the logical product of the outputs of the data latches 31a to 31c corresponding to each pair of adjacent light beams.
That is, if an object within a predetermined distance range is detected by two adjacent light beams, it is considered that the object has moved in one direction in a plane where the light beam is formed within the predetermined distance range. be able to.

For example, assuming that a person (considered an object) passes through a corridor, the distance to the object is almost constant and the moving direction is almost constant. Detection of presence or absence and the direction of movement may be required. The present embodiment can be used for such a purpose. That is, if the object moves in the y direction in the first embodiment, when an object is detected for two adjacent light beams among the three light beams, the two light beams are detected. It can be considered that the object has moved from the side where the beam is set to the side where the remaining one light beam is set.

In the configuration shown in FIG. 3, when an output (H level) is obtained in one of the two AND circuits 32a and 32b, the AND circuit 32a, 32A,
It can be determined that the object has moved from the side corresponding to 32b toward the other. For example, assume that the output corresponding to the leftmost light beam in FIG. 1A corresponds to the data latch 31a, the output corresponding to the central light beam corresponds to the data latch 31b, and the output corresponding to the rightmost light beam corresponds to the data latch 31c. Then, when an output is obtained from the AND circuit 32a, it means that the object has moved from left to right,
When an output is obtained from the AND circuit 32b, it means that the object has moved from right to left. The time during which the data latches 31a to 31c invert the output is set to a certain time according to the moving speed of the object to be detected. Here, when the AND circuits 32a and 32b are set to the positive logic, the outputs of the data latches 31a to 31c need only be set to the H level for a certain period of time. The L level may be set only for the time.

In this embodiment, the case where three light beams are formed has been described. However, in the case where four or more light beams are formed, the moving direction is calculated from the logical product of outputs of two light beams at both ends. Should be determined. Also, as shown in FIG. 4, it is possible to take out a signal corresponding to the moving direction with one output by binarizing the outputs of the AND circuits 32a and 32b. That is, each AND circuit 32
switch elements SWa and S
Wb are connected, and when an output (H level) is obtained from each of the AND circuits 32a and 32b, the other AND circuit 32
a, 32b, each switch element SWa, S
Wb is turned off. The output of the AND circuit 32b connected to one switch SWb is taken out through the inverting circuit 33. This inverting circuit 33
Are commonly connected to the output terminal T together with the switch element SWa. Each of the switch elements SWa and SWb is configured to be turned off when an output is not obtained from the connected AND circuits 32a and 32b. That is, when both switch elements SWa and SWb are off, the output becomes high impedance.

Therefore, when no object is present and no output is obtained from both AND circuits 32a and 32b, the output terminal T becomes high impedance. FIG.
In (a), when an object moves rightward and an output is obtained from the AND circuit 32a, the signal from the output terminal T becomes H level, and when the object moves leftward and an output is obtained from the AND circuit 32b, the output terminal is output. The signal from T goes to L level. Other configurations and operations are the same as those of the second embodiment.

In order to improve the determination accuracy in each of the above embodiments, the light projecting elements 11a to 11c are arranged in a straight line, and the direction in which the light projecting elements 11a to 11c are arranged and the width direction of the light receiving element 21 are set. Parallel placement is required. In other words, unless the distance between each of the light projecting elements 11a to 11c and the light receiving element 21 in the x direction described in the first embodiment is equal, the dimension BLD described in the conventional configuration is different for each of the light projecting elements 11a to 11c. Will vary. If the dimension BLD varies, the reference distance L corresponding to the light beam formed by each of the light projecting elements 11a to 11c varies.

Therefore, as shown in FIG.
A three-dimensional wiring board 40 on which the light receiving elements 21 are mounted is provided with a groove 41 for arranging the light projecting elements 11a to 11c and a groove 42 for arranging the light receiving element 21. As the three-dimensional wiring substrate 40, for example, an MID substrate is used. At least one side edge of each of the grooves 41 and 42 is a straight line parallel to each other. Therefore,
Each of the light emitting elements 11a to 11c and the light receiving element 21 are attached to the grooves 41, 42 in such a manner that the light emitting elements 11a to 11c and the light receiving elements 21 are in contact with the linear portions of the side edges parallel to each other in the grooves 41, 42, respectively. 11c are arranged in a straight line, and the light receiving element 21
It is possible to prevent the distance from the target from varying. In other words, if this configuration is adopted, the positional accuracy between the light projecting elements 11a to 11c and the light receiving element 21 can be reduced in the groove 4
It is possible to increase the processing accuracy to form the first and second 42.

If the light projecting elements 11a to 11c and the light receiving element 21 are mounted on the three-dimensional wiring board 40 in the following procedure, the light projecting elements 11a to 11c and the light receiving element 21 are located on the side edges of the grooves 41 and 42. The work of mounting in the abutted state is facilitated. That is, the light emitting elements 11a to 11a
By tilting the three-dimensional wiring board 40 as shown in FIG. 6 in a state in which the light-receiving elements 1c and the light-receiving elements 21 are inserted into the respective grooves 41, 42, the light-projecting elements 11a to 11c and the light-receiving elements The light emitting element 11 is brought into contact with the light emitting element 11 using an adhesive material such as silver paste.
a to 11 c and the light receiving element 21 are fixed to the three-dimensional wiring board 40. If such a procedure is adopted, the light emitting element 11a
11c and the light receiving element 21 can be prevented from varying.

Light projecting elements 11a to 11c and light receiving element 2
As shown in FIG. 7, the alignment between 1 and the three-dimensional wiring board 40 is performed by forming a convex portion 43 on one side and providing a concave portion (may be a hole) 44 engaging with the convex portion 43 on the other side. You may. In the illustrated example, a projection 43 is formed on the bottom surface of each of the grooves 41 and 42 formed on the three-dimensional wiring board 40, and the light projecting element 11 is formed.
Positioning is performed by forming a concave portion 44 in the light receiving elements 21a to 11c. Even with this configuration, variation in the distance between the light emitting elements 11a to 11c and the light receiving element 21 can be suppressed.

As a structure for positioning the light emitting elements 11a to 11c and the light receiving element 21, as shown in FIG.
5 can also be employed. That is, the light emitting elements 11 a to 11 c and the light receiving element 21 are mounted on the circuit board 45 using the solder balls (or solder bumps) 46. If this mounting technique is adopted, when the solder ball 46 is melted, the light emitting elements 11a to 11c and the light receiving element 21 are automatically aligned with the circuit pattern formed on the circuit board 45 by a self-alignment effect due to surface tension. Therefore, the positioning of the light emitting elements 11a to 11c and the light receiving element 21 can be performed with a precision of forming a circuit pattern. That is, even if such a mounting method is adopted, the light emitting elements 11a to 11a
Variations in the distance between 1c and the light receiving element 21 can be suppressed.

[0047]

According to the first aspect of the present invention, there is provided a light projecting means having a plurality of light projecting elements and forming a plurality of light beams from each light projecting element through a heavy rain light projecting optical system; A light receiving means for forming a light receiving spot by converging a light spot formed on the object when light is irradiated on the object through a light receiving optical system to a light receiving surface of the light receiving element, and an output value of the light receiving element according to a position of the light receiving spot Calculating means for judging the presence or absence of an object within a distance range set based on the distance, and the light emitting elements are arranged on one straight line in a plane orthogonal to the direction in which the light receiving spot moves according to the distance to the object. The width dimension of the light receiving element in the direction in which the light projecting elements are arranged is set to be greater than or equal to a dimension capable of forming a light receiving spot on the light receiving surface corresponding to all the light beams. Extensive because it forms a beam It is possible to detect objects in multiple directions, detect objects in multiple directions, and detect moving objects. In addition, each light emitting element shares one light emitting optical system and one light receiving element In this case, the light emitting device is relatively inexpensive than the light receiving device, so that the light emitting device is inexpensive and lower in cost as compared with the case where a plurality of light receiving devices are provided. In addition, if a plurality of light-receiving elements are provided, it is necessary to perform alignment of each light-receiving element, which is troublesome. However, when providing a plurality of light-emitting elements, only the arrangement direction needs to be considered. Matching is relatively easy.

According to a second aspect of the present invention, in the first aspect of the present invention, the light projecting means selectively emits light from each of the light projecting elements, and irradiates each light beam individually. Detection becomes possible.

According to a third aspect of the present invention, in the first aspect of the present invention, the light emitting means selectively emits light from each of the light emitting elements, and the calculating means separates the determination result of the light emitting period of each light emitting element. It is equipped with a decoder that takes out as a different output, and can scan the light beam and separate and extract the distance to the object corresponding to the light beam in each direction,
It is possible to detect the direction in which the object exists.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the light projecting means scans the light beam by causing each light projecting element to emit light cyclically, and the calculating means executes the light emitting period of each light projecting element. A data latch for temporarily holding at least outputs corresponding to a plurality of outputs at both ends in a scanning range of the light beam among the outputs of the decoder, and a light beam. And two AND circuits for respectively outputting the logical product of the judgment results held by the data latch corresponding to each of a plurality of lines at both ends in the scanning range. It is possible to know the direction in which the object has entered depending on whether or not is obtained. That is, if the object moves in the direction in which the light beam is scanned, the moving direction can be known.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, a substrate on which each of the light emitting elements and the light receiving elements is mounted is provided, and each of the light emitting elements and the light receiving elements is housed and projected. A pair of grooves having one side edge parallel to the direction in which the optical elements are arrayed are provided on the substrate, and the light projecting element and the light receiving element are respectively in contact with one side edge of each groove in the groove. Since the light projecting element and the light receiving element are positioned by the groove, the light projecting element and the light receiving element can be accurately positioned with the processing accuracy of the groove.

According to a sixth aspect of the present invention, there is provided the mounting method of the multi-beam type photoelectric sensor according to the fifth aspect, wherein the light projecting element and the light receiving element are brought into contact with one side edge of the groove by tilting the substrate. In this state, since the light emitting element and the light receiving element are mounted on the substrate, it is easy to make the light emitting element and the light receiving element abut on one side edge of the groove.

According to a seventh aspect of the present invention, in the first to fourth aspects of the present invention, a substrate on which each of the light emitting element and the light receiving element is mounted is provided, and a projection is provided on one of the light emitting element and the light receiving element and the substrate. And a concave portion for positioning the light emitting element and the light receiving element on the substrate by engaging with the convex portion is provided on the other side, and the light emitting element and the light receiving element and the substrate are accurately positioned by the concave and convex engagement. be able to.

According to an eighth aspect of the present invention, in the first to fourth aspects of the present invention, a substrate on which each light emitting element and the light receiving element are mounted is provided, and each light emitting element and the light receiving element are flip-chip mounted on the substrate. Therefore, when each of the light emitting element and the light receiving element is mounted on the substrate, the light emitting element and the light receiving element can be mounted in a state where the light emitting element and the light receiving element are aligned with the substrate by a self-alignment effect due to the surface tension of the solder.
As a result, the light emitting element and the light receiving element can be accurately positioned with the accuracy of the circuit pattern formed on the substrate.

[Brief description of the drawings]

1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is a perspective view showing an optical system, and FIG. 1B is a block diagram.

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a block diagram showing a third embodiment of the present invention.

FIG. 4 is a block diagram showing another configuration example of the above.

5A and 5B show a mounting state of a light projecting element and a light receiving element in the present invention, wherein FIG. 5A is a front view and FIG. 5B is a sectional view.

FIG. 6 is a diagram showing a mounting process of the above.

7A and 7B show another mounting state of the light emitting element and the light receiving element according to the present invention, wherein FIG. 7A is a front view and FIG. 7B is a sectional view.

FIG. 8 is a side view showing still another mounting state of the light emitting element and the light receiving element in the present invention.

FIG. 9 is a schematic configuration diagram showing a conventional example.

FIG. 10 is a diagram illustrating the principle of a light receiving element used in the light emitting element;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light projecting means 2 light receiving means 3 object 3 a to 3 c object 11 a to 11 c light projecting element 12 light projecting optical system 21 light receiving element 22 light receiving optical system 30 decoder 31 a to 31 c data latch 32 a, 32 b AND circuit 40 three-dimensional wiring board 41, 42 Groove 43 Convex 44 Concave 45 Circuit board 46 Solder ball

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[Procedure amendment]

[Submission Date] January 11, 2000 (2000.1.1)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

[0016]

[Means for Solving the Problems] of claim 1 the invention comprises a light projecting means for forming a plurality of light beams through each light emitting element or al projecting optical system comprises a plurality of light emitting devices, each A light receiving means for forming a light receiving spot by converging a light spot formed on the object when the light beam is irradiated onto the object through a light receiving optical system to a light receiving surface of the light receiving element; and a light receiving element corresponding to the position of the light receiving spot. Calculating means for determining the presence or absence of an object within a set distance range based on the output value, and a light emitting element on one straight line in a plane orthogonal to the direction in which the light receiving spot moves according to the distance to the object Are arranged, and the width dimension of the light receiving element in the direction in which the light projecting elements are arranged is set to be equal to or larger than a dimension capable of forming a light receiving spot on the light receiving surface corresponding to all light beams.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction contents]

[0047]

[Effect of the Invention] The invention of claim 1 includes a light projecting means for forming a plurality of light beams through each light emitting element or al projecting optical system comprises a plurality of light emitting devices, each light beam is the object A light receiving means for forming a light receiving spot by converging a light spot formed on an object when irradiated on the light receiving surface of the light receiving element through a light receiving optical system, and based on an output value of the light receiving element according to the position of the light receiving spot Calculating means for determining the presence or absence of an object within the set distance range, the light emitting elements are arranged on one straight line in a plane orthogonal to the direction in which the light receiving spot moves according to the distance to the object, The width dimension of the light receiving element in the direction in which the light projecting elements are arranged is set to be equal to or larger than a dimension capable of forming a light receiving spot on the light receiving surface corresponding to all the light beams. Wide range of things because they form It is possible to detect objects in multiple directions and to detect moving objects. In addition, each light emitting element shares one light emitting optical system and only one light receiving element is provided. Is relatively small,
Further, since the light projecting element is generally less expensive than the light receiving element, there is an advantage that the light emitting element is inexpensive and lower in cost than a case where a plurality of light receiving elements are provided. In addition, if a plurality of light-receiving elements are provided, it is necessary to perform alignment of each light-receiving element, which is troublesome. However, when providing a plurality of light-emitting elements, only the arrangement direction needs to be considered. Matching is relatively easy.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01S 5/026 H01S 3/18 616 F term (Reference) 2F112 AA07 BA02 BA10 DA02 DA15 DA26 DA32 EA05 EA11 FA01 GA01 5F041 CB22 DA83 DC81 EE11 FF16 5F049 MA01 NB07 RA02 RA07 TA03 TA11 5F073 AB02 AB25 BA09

Claims (8)

[Claims] 1. A light projecting means having a plurality of light projecting elements and forming a plurality of light beams from each light projecting element through a heavy rain light projecting optical system, and when each light beam is irradiated on an object. A light receiving means for forming a light receiving spot by converging a light spot formed on an object to a light receiving surface of the light receiving element through a light receiving optical system, and a distance range set based on an output value of the light receiving element according to the position of the light receiving spot Calculating means for determining the presence or absence of an object in the light emitting element, the light emitting elements are arranged on one straight line in a plane orthogonal to the direction in which the light receiving spot moves according to the distance to the object, and the light emitting elements are arranged A width dimension of the light receiving element in a direction to be set is set to be equal to or larger than a dimension capable of forming a light receiving spot on a light receiving surface corresponding to all light beams. 2. The multi-beam photoelectric sensor according to claim 1, wherein said light emitting means causes each light emitting element to emit light alternatively. 3. The light-emitting device according to claim 1, wherein the light-emitting device selectively emits light from each of the light-emitting devices, and the calculating device includes a decoder that separates the determination result of the light-emitting period of each light-emitting device and outputs the result as a different output. 2. The multi-beam photoelectric sensor according to claim 1, wherein: 4. The light projecting means scans a light beam by causing each light projecting element to emit light cyclically, and the calculating means separates the judgment result of the light emitting period of each light projecting element and outputs a different output signal. A data latch that temporarily holds outputs corresponding to at least a plurality of both ends in the light beam scanning range among outputs of the decoder, and a plurality of both ends in the light beam scanning range 2. The multi-beam photoelectric sensor according to claim 1, further comprising: two AND circuits each outputting a logical product of the determination results held by the data latch corresponding to the above. 5. A substrate on which each of the light emitting element and the light receiving element is mounted, wherein each of the light emitting element and the light receiving element is housed, and one side edge along a direction in which the light emitting elements are arranged is parallel to each other. And a pair of grooves formed on the substrate, wherein the light projecting element and the light receiving element are fixed in the grooves so as to abut against the one side edge of each groove, respectively. Item 5. A multi-beam photoelectric sensor according to any one of Items 4. 6. The mounting method of a multi-beam photoelectric sensor according to claim 5, wherein the light projecting element and the light receiving element are brought into contact with the one side edge of the groove by tilting the substrate. Mounting a light emitting element and a light receiving element on the substrate. 7. A light-emitting element by providing a substrate on which each light-emitting element and light-receiving element are mounted, providing a projection on one of the light-emitting element, light-receiving element and the substrate, and engaging with the projection. 5. The multi-beam photoelectric sensor according to claim 1, wherein a concave portion for positioning a light receiving element on the substrate is provided on the other side. 8. A substrate on which each light emitting element and light receiving element are mounted, wherein each light emitting element and light receiving element are flip-chip mounted on the substrate.
The multi-beam photoelectric sensor according to claim 4.