JPS587515A - Distance measuring device - Google Patents

Abstract

PURPOSE:To make it possible to perform highly accurate distance measurement, by arranging a light receiving region restricting means in front of a light receiving means, making its position variable, and equalizing the size of the projected image with the size of the light receiving region. CONSTITUTION:A variable mask 8 is arranged in front of the light receiving element 5. The light projecting axis and the light receiving axis are aligned by adjusting the apperture of the mask. The focal point surface of a light receiving lens 4 is located in the vicinity of the mask 8, and the lens 4 receives the light from a constant range 7 on an object 1. As a result, the excellent signal can be always received by simple adjustment, regardless of the dispersion of the light receiving element, degradation in attaching accuracy, and the like. Thus the highly accurate distance measurement is always performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an active distance measuring device. Various types of distance measuring devices have been proposed in the past. One of them is an active 11° field distance in which an energy projection source (e.g., an infrared light emitting diode and a light emitting lens) and an energy receiver (e.g., a silicon light receiving element and a light receiving lens) are arranged at predetermined intervals by applying the principle of so-called triangulation. The device is advantageous in that it is less sensitive to the shape of the object 09'.

For example, the applicant's %II @ 54-140562
As disclosed in the publication, the method of moving the light source or light receiving part is extremely useful because it enables high-precision distance measurement with a simple configuration, but as has been pointed out, The fact that the light emitting element and the light receiving element are the same size is called superposition. However, when light emitting diodes, which are generally used as a light source in a method such as the one described above, are manufactured in large quantities, there is no difference in size. occurs, and if this variation is left as it is, it will cause a decrease in accuracy. On the other hand, if elements are selected in order to prevent this, the cost will increase.

This light source #4 is a round type designed with attention to the stiffness.The light receiving area limiting means is installed in front of the light receiving means, and by making this variable, the light emitting element go and light receiving area O
The aim is to realize a low-cost, high-precision distance measuring device with the same size.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. Figure 1 shows the basic configuration of an embodiment of the active distance measuring device according to the present invention. A light source such as a smoked infrared light emitting diode, 2 is a condensing lens placed in front of the light source, and the light source 30 has a light emitting part near its focal plane, which forms an image 1Ii(1) on p1 object l. is formed. ・5 is a light receiving element such as a silicon photodiode, 8 is a mask with a variable aperture as a variable light receiving area limiting means placed just in front of it, and 4 is a light receiving lens placed in front of it.
The dotting is done in the vicinity of the mask 8 in a certain area 7 on the object 1.
When the light 113 is moved in the direction of the arrow along 1,000 mK including the emitting optical axis and the receiving optical axis and scanned over the light receiving range 7, the light receiving element 5VcFi mask Reflected light enters through 8 and generates an electrical signal. At this time, the distance between lens 4 and object l is L1
The distance between both lenses 2 and 4 is D, and the deflection angle of the light 63 is -
In the case of Toshimaru, it is given by L"tan#.

At this time, the waveform of the signal light incident on the light receiving element 5 is $183.
As shown in WA, if the peak of this waveform is detected, the emitting and receiving optical axes will match, that is, the angle θ mentioned above can be found.
Object distance can be detected @In this case, if the size of the emitted image and the received image are different on the object plane, the beak becomes flat as shown in the signal waveform al14 above, and noise etc. Due to the influence of By aligning the receiving optical axes well, a good signal as shown in Figure 3 can be obtained with simple adjustment, and high precision can be achieved regardless of the uneven alignment of the P1 receiving bulkhead 5 and deterioration of Kjl attachment accuracy. C) 14 distances can be carried out. Figure 5 shows details of an example of a mask 80 placed just before the light receiving element 5. Reference numeral 11.12 is a mask plate, which is attached to a part of the light receiving element holder (not shown). It is fixed and rotatably supported on a round shaft 13, and is engaged with a pin 14a at the tip of an adjustment lever 1412) at the long extending portions 11m and 121, respectively.Adjustment lever 14t1 also includes a light receiving element holder, etc., not shown. The tail end has a notch 14b for adjustment and a length for engaging with a screw 16 for fixation.
5146. In such a configuration, the - joint lever 14 can be cut in the notch 14b K at the tail end thereof by, for example, a screwdriver uniform O tool according to the engagement of its length @1i14c with the screw 16. By moving the bottle 14m up and down as shown by the middle arrow, the mask plate 11 is connected to the long grooves 1111m and 12m of the bottle 14m.
．． 12 is relatively displaced, thereby changing the size of the aperture formed, and thus the light receiving area of the light receiving element 5 can be adjusted. Of course, the lever 14 can be fixed by firmly screwing in the screw 16 at an appropriate position.

In addition, as a modification of the present invention, for example, by adjusting the position of the mask O with respect to the light receiving element, 7 lines between the light receiving element and the light emitting element may be obtained. This was done by moving the light emitting element or the light receiving element, which resulted in a complicated mechanism and problems with the handling of lead wires, etc. However, by using the present invention, alignment can be achieved extremely easily with a simple mechanism. i of
! 1 adjustment is possible.

As described in detail above, according to the present invention, the light emitting area of the light emitting means and the light receiving area of the photoreceiver 1IRe) can be well matched with a very simple configuration and a very simple adjustment. Therefore, when there are unavoidable variations in the light-receiving means, distance measurement is very easy even when the accuracy of the projection and light-receiving means is degraded. Since it is possible to maintain accuracy, it is possible to obtain a high-performance distance measuring device at extremely low cost, and the effect of this type of active mofs* device is enormous.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment o11 of the active glue distance device according to the present invention.
A schematic diagram showing the ring configuration, 2nd @ is an OII formula diagram to explain distance measurement *ll with the configuration in Figure 1, and Figure 3 shows a good projection image by the light projecting means and the light receiving area of the light receiving means. 4 is a diagram showing a model of the output waveform of the light receiving means when they coincide with each other. FIG. FIG. 5 is a diagram showing a model of the output waveform. FIG. 5 is a diagram showing a specific example of a mask as a means for receiving a light receiving area of 2g. 3--Light source as light projecting means, 2... Light projecting lens,
5.--Light-receiving element as light-receiving means, 4--Lens for light-receiving, 8--O masks 11, 12 as light-receiving area limiting means
-・Mask plate, 14-・Adjustment lever.

Claims (1)

[Claims] (1) In a nine-active distance measuring device comprising a light projecting means and a light receiving means arranged at a predetermined distance apart, a variable limiting means is provided in front of the light receiving means for limiting the light receiving area. A distance measuring device according to claim 1(1), comprising 92 blades with the limiting means rotating about the same axis.