JPH063111A - Measuring apparatus of distance - Google Patents

Abstract

(57) [Summary] [Purpose] To be able to determine whether the distance is closer or farther than the range. [Structure] A light emitting element 30 and a light projecting lens 32 project measuring light onto an object whose distance is to be measured. A light receiving element 34 is provided beside the light emitting element 30 to detect the presence or absence of reflected light from an object at the closest distance. Reflected light from an object at a normal distance enters a light receiving element 38 including a line sensor via a light receiving lens 36. Next to the light receiving element 38, a light receiving element 40 for receiving the reflected light from an object closer than the distance measuring range is arranged. The determination circuit 42 determines whether the distance is closer or farther than the distance measuring range based on the output states of the light receiving elements 34, 38, 40, and causes the display circuit 44 to display.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device for projecting light on an object and measuring the distance to the object by the light reflected and returned.

[0002]

2. Description of the Related Art FIG. 4 shows an optical system of a conventional example of such a light projection type distance measuring device. In FIG. 4, 10 is a light emitting element, 12 is a light projecting lens, 14 is a light receiving lens, and 16 is a light receiving element composed of a line sensor in which a plurality of photoelectric conversion elements are linearly arranged in a direction away from the light emitting element 10. .
The light receiving lens 14 and the light receiving element 16 are arranged laterally apart from the light emitting element 10 and the light projecting lens 12 by a predetermined distance. Reference numerals 18, 20, 22, and 24 are reflecting objects positioned on the light projection optical axis as distance measuring objects. The object 18 is located at the closest position, the object 20 is located at the short range end of the range measurement range, the object 22 is located within the range range measurement, and the object 24 is located at the far range end of the range range measurement. To do.

The light projected by the light emitting element 10 and the light projecting lens 12 is reflected by the objects 18, 20, 22, 24 and enters the light receiving element 16 via the light receiving lens 14. The incident position of the reflected light from each of the objects 18, 20, 22, 24 on the light receiving element 14 is determined by the object 18, 20, 22, 2
Depends on distance to 4. Based on the principle of triangulation, the distance to the objects 18, 20, 22, 24 can be easily obtained.

[0004]

However, in the above-described conventional example, an object outside the measurable range or out of the range such as an object too close (for example, object 18) or an object too far away (for example, object 24) is used. The reflected light is not clearly detected by the light receiving element 16. In such a case, there is a problem that it is not possible to determine whether the objects 18 and 24 reflecting the projection light are near or far.

An object of the present invention is to provide a distance measuring device that solves such a problem.

[0006]

A distance measuring apparatus according to the present invention includes a light projecting optical system for projecting measuring light onto an object whose distance is to be measured, and a light projecting optical system disposed beside the light projecting optical system at a predetermined distance. A distance measuring device comprising a light receiving optical system for receiving reflected light from a distance measuring object, and measuring the distance to the distance measuring object by the incident position of the reflected light in the light receiving optical system. A first light receiving element for receiving the reflected light incident on the system is provided in the light projecting optical system, and a second light receiving element for receiving the reflected light from the object closer to the distance-measurable near end is provided in the light receiving optical system. It is characterized by that.

[0007]

With the first and second light receiving elements, it is possible to know that the projected light is reflected by an object closer to the distance measuring range than the near end. If no output is obtained from the light receiving means for determining the distance of the light receiving optical system or the first and second light receiving elements, a reflecting object is present on the projection optical axis within the measurable range. Since it does not exist, it is possible to detect such a state in which measurement is not possible or measurement is not necessary, and it is possible to avoid unnecessary operation and power consumption.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of an embodiment of the present invention. Reference numeral 30 denotes a light emitting element that emits projected light, and 32 denotes a light projecting lens. 34 are arranged. 36 is a light receiving lens,
Reference numeral 38 is a light receiving element including a line sensor in which a plurality of photoelectric conversion elements are arranged on a straight line in a direction away from the light emitting element 30. A front view of the light receiving element 38 is shown in FIG. In FIG. 3, 38a is a line sensor and 38b is a light receiving window. A light receiving element 40 facing the light receiving lens 36 is arranged on the side of the light receiving element 38 which is remote from the light emitting element 30. The light receiving elements 34 and 40 are composed of a single photoelectric conversion element.

Reference numeral 42 is a judgment circuit for judging the distance from the outputs of the light receiving elements 34, 38, 40 to the object, and whether or not the reflecting object is within the distance measuring range. Reference numeral 44 is a judgment result by the judgment circuit 42 ( This is a display circuit for displaying an object distance, or distance measurement by short distance or long distance).

FIG. 2 shows a ray diagram for distance measurement in FIG. Four
Reference numerals 8, 50, 52 and 54 are reflective objects positioned on the light projection optical axis as distance measurement objects. The object 48 is located at the closest position, the object 50 is located near the near range end of the range-finding range, the object 52 is located within the range range, and the object 54 is near the far range end of the range range. Located in. Reference numeral 30a denotes a light projecting optical axis formed by the light projecting element 30 and the light projecting lens 32.
8a and 48b are reflected light from the object 48, and 50a and
52a and 54a are light reflected by the objects 50, 52 and 54, respectively.

That is, the reflected light 48 from the nearest object 48
Of a and 48b, the reflected light 48a toward the light receiving lens 36
Has a too large incident angle and does not enter either of the light receiving elements 38 and 40. However, the reflected light 48b is reflected by the projection lens 3
It is incident on the light receiving element 34 via 2.

The reflected light 50a from the object 50 located near the near-distance end of the measurable range enters the light receiving element 38 or the light receiving element 40 through the light receiving lens 36. Light receiving element 3
When incident on 8, the distance can be measured and the light receiving element 40
When the object 50 is incident on, the object 50 is located outside the range in which the distance can be measured, and the display circuit 44 displays that fact, as will be described later.

The reflected light 52a from the object 52 located within the distance measuring range passes through the light receiving lens 36 and the light receiving element 38.
Incident on. The distance can be measured by the incident position on the light receiving element 38. Further, the reflected light 54a from the object 54 located near the far end of the distance measuring range is incident on the light receiving element 38 via the light receiving lens 36, and similarly, the distance can be measured by the incident position on the light receiving element 38. .

When there is no reflecting object within the distance measuring range, or when the reflecting object is located far beyond the distance measuring range, the reflected light does not enter any of the light receiving elements 34, 38, 40. .

In this way, the output states of the light receiving elements 34, 38, 40 change according to the distance to the object that reflects the projected light. The determination circuit 42 includes the light receiving elements 34, 38, 40.
Whether or not the reflective object is located within the distance-measurable range is determined based on the presence or absence of the output, and if the reflective object is located within the distance-measurable range, the distance is determined. Specifically, the determination circuit 42
When the light receiving element 38 outputs a signal, the distance is determined by determining that the reflecting object is within the distance measuring range regardless of whether the light receiving elements 34 and 40 output, and the display circuit 44
To display the distance. When the light receiving element 34 outputs a signal when the light receiving element 38 does not output a signal,
A short-distance warning is displayed by the display circuit 44, and the light receiving element 4
When 0 outputs a signal, the display circuit 44 displays a warning indicating that the distance is the shortest distance. When no signal is output from any of the light receiving elements 34, 38, 40, the display circuit 44 displays a warning that there is no reflecting object on the projection optical axis within the measurable range.

[0017]

As can be easily understood from the above description, according to the present invention, the reason why distance measurement is impossible can be distinguished and judged. Therefore, even though distance measurement is impossible, distance measurement is not continued, and unnecessary operation and power consumption can be avoided.
Coordination with other devices becomes easy.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a projected light ray diagram of the present embodiment.

FIG. 3 is a front view of a light receiving element 38 of this embodiment.

FIG. 4 is a projection light beam diagram of a conventional example.

[Explanation of symbols]

10: Light emitting element 12: Light emitting lens 14: Light receiving lens 16: Light receiving element 18, 20, 22, 24: Reflecting object 30: Light emitting element 30a: Light emitting optical axis 32: Light emitting lens 34: Light receiving element 36: Light receiving lens 38: light receiving element 38a: line sensor 38b: light receiving window 40:
Light receiving element 42: Judgment circuit 44: Display circuit 48, 5
0, 52, 54: reflective objects 48a, 48b, 50a,
52a, 54a: reflected light

Claims (1)

[Claims] 1. A light projecting optical system for projecting measuring light onto an object of a distance measuring object, and a light receiving device which is arranged beside the light projecting optical system at a predetermined distance and receives reflected light from the object of the distance measuring object. A first light receiving device for receiving a reflected light incident on a light projecting optical system, the distance measuring device comprising an optical system and measuring a distance to an object of a distance measurement target by an incident position of the reflected light in the light receiving optical system. A distance measuring device, wherein an element is provided in a light projecting optical system, and a second light receiving element for receiving reflected light from an object closer to a distance-measurable near end is provided in the light receiving optical system.