JPH08122056A - Optical range-finding sensor - Google Patents

Abstract

PURPOSE: To perform the detection in a wide range by reducing the error due to the side deviation of an object to be detected by performing a relatively simple improvement. CONSTITUTION: A light emitting part 11 and a light reception part 14 are provided in the horizontal direction. The light emitting part 11 consists of a light emitting element 12 and a beam stopping-down lens 13, the emission beams are regulated by the beam stopping-down lens 13, an application area 18 for a detection object 17 is made thin. The light reception part 14 consists of a cylindrical lens 15 and a position detection element 16 and the cylindrical lens 15 leads the reflection light from an arbitrary position of an application area 18 to the position detection element 16. The position detection element 16 outputs a signal corresponding to the distance between the sensor and the detection object 17 according to the incidence position in the longitudinal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a triangulation type optical distance measuring sensor.

[0002]

2. Description of the Related Art As a conventional triangulation type optical distance measuring sensor, there is one shown in FIG. In FIG. 9, reference numeral 1 is a light emitting portion including a light emitting element 2 and a lens 3, 4 is a light receiving portion including a lens 5 and a light receiving element (position detecting element: PSD) 6, and 7 is a detection object. When the light emitted from the light emitting unit 1 is applied to the detection object 7 and the reflected light from the detection object 7 is incident on the light receiving element 6 of the light receiving unit 4, the incident positions are the detection object 7 and the optical distance measuring sensor. The distance between the sensor and the detected object is measured by utilizing the fact that the distance changes depending on the distance. That is, next to a ₁ is the incident position of the light receiving element 6 when the detection object 7 is in the 7a, next b ₁ is incident position when the detection object 7 is in 7b, until the detected object in accordance with a change in the incident position To measure the distance.

In the above-mentioned conventional optical distance measuring sensor, it is necessary to make the emission beam diameter small (the spot diameter small). The reason is as follows.

When the emission beam diameter is large, the measurement error becomes large when the detected object is small.

As shown in FIG. 10, when the detected object 7 shifts in the lateral direction with respect to the sensor, the sensor output changes, causing an error. That is, if the detected object 7 is not displaced, the incident position is a ₂ , but since the detected object 7 is laterally displaced, the incident position is a ₃ and the detection distance is longer than it actually is.

The above problems can be solved by reducing the emission beam diameter.

However, when the diameter of the emission beam is reduced, the area irradiated by the emission beam is narrowed and the area where the detection object is detected is also narrowed. When the detection object deviates from the emission axis of the sensor, the detection object is detected. It's gone.

In order to solve such a problem, conventionally, as shown in FIG. 11, a plurality of light emitting parts 1a, 1b,
A method has been proposed in which 1c are arranged side by side in the lateral direction, and these light emitting portions are made to emit light in a time series to widen the detection area.

Further, as shown in FIG. 12, a plurality of light receiving portions 4a and 4b are provided, and a signal due to the light incident on these plurality of light receiving portions is subjected to a correlative process to obtain an error due to lateral displacement of the detected object 7. A method of correcting the is proposed.

[0010]

In the method of enlarging the detection area as shown in FIG. 11 and the method of correcting the error due to the lateral displacement of the detected object as shown in FIG. 12, a plurality of light emitting parts and a plurality of light emitting portions are used. Needing a light-receiving part, which complicates the control circuit and the signal processing circuit, which not only increases the cost but also increases the size of the sensor. There was a problem that axis alignment and positioning were difficult.

The present invention was devised in view of the above circumstances, and while only making a relatively simple improvement, the error due to the lateral displacement of the detected object is reduced, and the area is wide. The purpose is to enable detection.

[0012]

According to the optical distance measuring sensor of claim 1 of the present invention, the light emitted from the light emitting portion is applied to the detection object, the reflected light from the light is incident on the light receiving portion, and the incident light is input. An optical distance measuring sensor of a triangulation method for measuring a distance to a detection object according to a position, wherein the light emitting section has a shape of a light emission beam narrow in a direction connecting the light emitting section and the light receiving section and It is characterized in that the irradiation area which is wide in the direction perpendicular to the direction and in which the detection object is irradiated by the emission beam is elongated.

An optical distance measuring sensor according to a second aspect of the present invention is the optical distance measuring sensor according to the first aspect, wherein the light receiving section is elongated in a direction connecting the light emitting section and the light receiving section, and the position detecting element. It is characterized in that it is composed of a cylindrical lens arranged at a right angle to the position detection element on the front surface of the element.

[0014]

In the optical distance measuring sensor according to the first aspect, since the irradiation area for the detection object is long and narrow, even if the detection object is slightly laterally displaced or the detection object is small, the irradiation area is large. Since a part or a part hits the detection object, the error of the measurement distance due to the lateral displacement of the detection object becomes sufficiently small. In other words, this means that the detection area for the detection object is expanded. In addition, making the emission beam elongated as described above is a relatively simple improvement, and not only suppresses cost increase and sensor size increase, but also uses general control circuits and signal processing circuits. You may

In the optical distance measuring sensor of the second aspect, the light reflected from any part of the wide irradiation area is made incident on the light receiving portion by passing through the cylindrical lens. Since the position detecting element arranged at right angles to the cylindrical lens is used as the light receiving element, the reflected light from any part of the irradiation area or the reflected light from the entire irradiation area can be detected in the longitudinal direction of the position detecting element. It will be incident on the same position.

[0016]

Embodiments of the optical distance measuring sensor according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing a schematic structure of an optical distance measuring sensor of the embodiment. The light emitting unit 11 includes a light emitting element 12 such as a light emitting diode (LED) and a beam diaphragm lens 13 arranged in front of the light emitting element 12. Light receiving unit 1 arranged on the lateral side of the light emitting unit 11.
4 is a position detecting element (PSD) 16 as a light receiving element
And a cylindrical lens 15 arranged in front of the position detecting element 16. Reference numeral 17 is a detected object.

Beam stop lens 13 in light emitting section 11
As shown in FIG. 2, has a narrow directivity when viewed in the direction of FIG. 2A and has a wide directivity when viewed in the direction of FIG.
That is, when viewed in the direction of FIG. 3A, the light-emitting beam from the light-emitting element 12 is condensed by the condensing action of the lens, so that the light-emitting beam is narrowed into substantially parallel rays and emitted. When viewed in the direction of FIG. 2B, the emitted light beam is hardly condensed, and the directivity of the single light emitting element can be obtained. That is, as shown in FIG. 1, the shape of the beam emitted from the beam diaphragm lens 13 is narrow in the direction connecting the light emitting unit 11 and the light receiving unit 14 and wide in the direction perpendicular to the direction, and the detected object 17 The irradiation area 18 is sufficiently elongated.
In this case, by using the light emitting element 12 having a relatively wide directivity, the irradiation area 18 can be made sufficiently elongated.

The structure of the light emitting portion 11 for obtaining the elongated irradiation area 18 may be as shown in FIG. This uses a concave lens 19 and a slit plate 20. Reference numeral 20a is an elongated rectangular slit hole formed in the slit plate 20.

When viewed from the direction shown in FIG. 2B, the light beam emitted from the light emitting element 12 is diffused by the concave lens 19 and the slit hole 2
Emits through a wide portion of 0a. As a result, it is possible to obtain a wider directivity than that of the light emitting element alone. When viewed in the direction (a) of the figure, a part of the emission beam diffused by the concave lens 19 is blocked by the slit plate 20, and the remaining beam is emitted through the narrow portion of the slit hole 20a. This results in a flat fan-shaped beam. If the light emitting element 12 having a relatively wide directivity is used, the concave lens 19 may be omitted and the slit plate 20 may be omitted.
The elongated irradiation area 18 can be obtained only by itself.

Alternatively, as shown in FIG. 4, the light emitting element 1
The 2 itself may have a directivity for emitting a light emission beam for obtaining the elongated irradiation area 18. In this case, the lens and the slit plate can be omitted.

Further, as shown in FIG. 1, the position detecting element 1
6 is arranged so as to be elongated in the direction connecting the light emitting portion 11 and the light receiving portion 14, and the cylindrical lens 15 is arranged on the front surface of the position detecting element 16 at a right angle to the position detecting element 16. Cylindrical lens 15
Transmits the reflected light as shown in FIGS. 5 (a) and 5 (b), which allows the detected object 1 to be transmitted as shown in FIG.
7 in any position of the irradiation area 18 (A point B
The reflected light can be received by the position detecting element 16 (at a point or at other positions), and the light receiving position is the same in the longitudinal direction of the position detecting element 16 regardless of whether it is at the point A or at the point B. .

As described above, since the irradiation area 18 for the detection object 17 is long and narrow, even if the detection object 17 laterally shifts in the direction of the arrow in FIG. 1 or the detection object 17 is small, the irradiation area 18 is small. If a part of the object hits the object to be detected, the reflected light from the object will always be present, and the position detecting element 1 will pass through the cylindrical lens 15.
6 can be made incident.

Detecting object 17 on which irradiation area 18 is formed
Is closer to the sensor, the incident position on the position detecting element 16 is farther from the light emitting unit 11, and the farther the detection object 17 is from the sensor, the incident position on the position detecting element 16 is closer to the light emitting unit 11. Thereby, the distance between the sensor and the detected object 17 can be measured.

[Example 1 of use] As shown in FIG. 7, the optical distance measuring sensors S configured as described above are attached to a plurality of positions on the rear portion of the automobile 30. Each sensor S has a flat fan-shaped irradiation area 18. When an obstacle 31 enters the irradiation area 18 and the distance between the sensor S and the obstacle 31 becomes a predetermined value or less, an alarm sound is emitted. The driver who hears this alarm sound stops the backward movement of the automobile 30 and avoids the collision with the obstacle 31. Instead of sounding an alarm sound, you may blink the warning lamp,
The distance to the detected object may be displayed on an indicator or a monitor by the sensor output.

Compared with the conventional example in which the diameter of the emission beam is narrowed down, the conventional example has a narrow detection area, so that a protruding object or a pole-shaped obstacle is difficult to detect, and a sensor is required for reliable detection. It is necessary to provide a large number of without gaps and to have a mechanism to move the sensor left and right,
If this is the case, the cost will be high and the appearance will be impaired.

Compared with this, when the optical distance measuring sensor S of this embodiment is used, the number of sensors is small, which is advantageous in terms of cost. It is effective as a back sensor when entering a garage. Distance sensors between cars and sidewalks and other obstacles during parallel parking, sensors to prevent front and rear cars from colliding, and to avoid collisions with obstacles such as parking in narrow parking lots and turning back on narrow roads. It can be effectively used as a sensor.

[Use Example 2] As shown in FIG. 8, the optical distance measuring sensor S is attached to the automatic transport robot 32. The presence or absence of the obstacle 33 in the moving direction or its surroundings and the distance are detected, and when the distance is less than or equal to a predetermined value, an alarm sound is emitted or a warning lamp is blinked. When the distance becomes too small, the movement of the automatic transfer robot 32 is automatically stopped.

[Other Example of Use] A wash basin that automatically detects when the hand is put out and automatically supplies water.

An air dryer for a toilet that detects the hand when it is put out and blows out warm air.

In all of these, the irradiation area of the sensor is fan-shaped, so that the position where the hand is placed may be rough.

An automatic vending machine that detects a human body and emits a sound such as “Welcome to you”.

A sensor for opening and closing an automatic door.

Security sensor.

An ON / OFF sensor for the screen of a word processor.

A sensor for turning on / off the power of the copying machine.

A sensor for adjusting the volume of AV equipment.

A sensor for adjusting the air flow of the fan.

[0039]

According to the optical distance measuring sensor of the first aspect, since the irradiation area for the detection object is long and narrow, even if the detection object is laterally displaced or the detection object is small, the irradiation area is small. Since at least a part of the incident light impinges on the detection object and the reflected light is incident on the light receiving portion, the error in the measurement distance due to the lateral displacement of the detection object can be sufficiently reduced. The elongated shape of the emission beam is a relatively simple improvement, and not only does the cost increase and the size increase of the sensor be suppressed, but general control circuits and signal processing circuits can be adopted.

According to the optical distance measuring sensor of claim 2,
The light reflected from any part of the wide irradiation area is made incident on the light receiving portion by passing through the cylindrical lens. Since the position detecting element arranged at right angles to the cylindrical lens is used as the light receiving element, the reflected light from any part of the irradiation area or the reflected light from the entire irradiation area can be detected in the longitudinal direction of the position detecting element. The light can be made incident on the same position, and the distance measuring operation can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an optical distance measuring sensor according to an embodiment of the present invention.

2A and 2B are a front view and a side view showing the shape and operation of the beam diaphragm lens in the example.

FIG. 3 is a front sectional view and a side sectional view showing another embodiment of a light emitting unit.

FIG. 4 is a perspective view showing still another embodiment of the light emitting unit.

5A and 5B are a front view and a side view showing the shape and operation of the cylindrical lens in the example.

FIG. 6 is a perspective view showing operations of a cylindrical lens and a position detection element.

7A and 7B are a side view and a plan view showing a usage example 1 of the optical distance measuring sensor.

FIG. 8 is a side view showing a second usage example of the optical distance measuring sensor.

FIG. 9 is a front view showing a conventional optical distance measuring sensor.

FIG. 10 is an explanatory diagram of a defect of the conventional optical distance measuring sensor.

FIG. 11 is a front view showing another conventional optical distance measuring sensor.

FIG. 12 is a front view showing still another conventional optical distance measuring sensor.

[Explanation of symbols]

 11 ... Light emitting part 12 ... Light emitting element 13 ... Beam diaphragm lens 14 ... Light receiving part 15 ... Cylindrical lens 16 ... Position detecting element (light receiving element) 17 ... Detecting object 18 ... Elongated irradiation area 19 ... Concave lens 20 ... Slit plate 20a ... Slit hole

Claims (2)

[Claims] 1. A triangulation type optical measuring system for irradiating a detection object with light emitted from a light emitting section, making reflected light from the light incident on a light receiving section, and measuring the distance to the detection object according to the incident position. In the distance sensor, the shape of the light emitting beam from the light emitting unit is narrow in a direction connecting the light emitting unit and the light receiving unit and wide in a direction perpendicular to the direction, and an irradiation area irradiated with a detection object by the light emitting beam. An optical distance measuring sensor characterized by being elongated. 2. A light-receiving part is composed of a position detecting element arranged in a slender shape in a direction connecting the light-emitting part and the light-receiving part, and a cylindrical lens arranged on the front surface of the position detecting element at right angles to the position detecting element. The optical distance measuring sensor according to claim 1, wherein the optical distance measuring sensor is configured.