JPH0850178A - Optical wave range finder - Google Patents

Abstract

PURPOSE:To provide an optical wave range finger in which the measuring precision can be improved with a simple structure. CONSTITUTION:The emitted light 3 generated by an emitting means 2 is reflected by a reflecting means arranged in a measuring point, and the reflected light 6 is damped by an optical quantity damping means 4 and received by a light receiving means 5 to measure the distance of the measuring point. The optical quantity damping means 4 has rotating filter plates 10, 101, 102 having a plurality of unit filters 111-118 differed in light damping factor provided in the circumferential direction, and the rotating filter plates 10, 101, 102 are arranged on the optical path of the reflected light 6 in such a manner as to be rotatable around a rotating axial line 12 substantially parallel to the optical path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rangefinder, and in particular,
The present invention relates to a lightwave rangefinder using lightwaves.

[0002]

2. Description of the Related Art A light-wave rangefinder irradiates light (laser light, LED light, etc.) from a light emitting means to a prism arranged at a measurement point, and a phase delay of reflected light reflected and returned by the prism. Is a device that automatically detects the distance from the point where the lightwave rangefinder is placed to the measurement point, and is indispensable for surveying work.

This phase delay divides the light whose brightness is modulated at a constant frequency into reference light and emitted light. The reference light is guided to a light receiving element in the optical distance measuring device, and the emitted light is reflected by a prism to be reflected light. The light is received by the light receiving element, the phase of the reflected light is compared with that of the reference light, and the phase delay is obtained. In that case, since the measurement accuracy is improved by comparing the reference light and the reflected light with the same light amount level, it is desirable that the light intensity of the reflected light and the light intensity of the reference light match.

However, since the emitted light such as laser light and LED light is not a perfect parallel light flux, the emitted light spreads as the measurement point becomes distant and the traveling distance of the emitted light increases. Therefore, the light intensity of the reflected light incident on the light distance measuring device decreases as the measurement point becomes distant, and the light intensity of the reflected light does not match the light intensity of the reference light.

Therefore, in the prior art, the light quantity attenuating means 100 as shown in FIG. 3 is arranged in front of the light receiving element 102, and the light receiving element 102 receives light by adjusting the light intensity of the reflected laser light.

To briefly explain this, the light quantity attenuating means 100 has a rotary filter plate 101, and the reflected laser light 104 reflected by the prism and incident on the optical rangefinder is the rotary filter plate 101. The transmitted light 105 that is incident on the rotary filter plate 101 is incident on the light receiving element 102.

The rotary filter plate 101 is constructed so that the amount of light attenuation gradually changes in the circumferential direction.
_The motor 107 is configured to rotate about the rotation axis 108 via ₁ , 106 ₂ , and 106 ₃ .

A CPU 109 is connected to the light receiving element 102, and the CPU 109 is a motor controller 11
The rotary filter plate 101 is connected to the motor 107 via 0, and the rotary filter plate 101 is rotationally controlled by the motor 107 so that the amount of the transmitted light 105 incident on the light receiving element 102 becomes constant.

However, it is not easy to manufacture a filter whose attenuation factor gradually changes in the circumferential direction. Moreover, the gradual change rate of the attenuation rate is often different for each production lot, and the quality is not constant.

Further, it is necessary that the portion irradiated with the reflected light 104 does not move across the portion of the rotary filter plate 101 having the largest attenuation rate and the portion having the smallest attenuation rate. Therefore, the gear 106 ₃ is provided with a stopper, the gear 106 ₁ and the motor 107 are connected through a slip mechanism 111, and the rotary filter plate 101 is configured so as not to rotate more than one rotation. Had to be complicated.

[0011]

SUMMARY OF THE INVENTION The present invention was created in view of the disadvantages of the prior art described above, and an object of the present invention is to provide an optical distance measuring device having a simple structure and capable of improving measurement accuracy.

[0012]

In order to solve the above problems, the invention according to claim 1 is a light emitting means for emitting emitted light, and a light quantity attenuating means for transmitting and attenuating the light quantity of the irradiated light. A light receiving unit is provided, and the emitted light is reflected by a reflecting unit arranged at a measuring point to become a reflected light, and the reflected light is attenuated by the light amount attenuating unit and received by the light receiving unit, An optical distance measuring instrument for measuring a distance, wherein the light amount attenuation means has a rotary filter plate provided with a plurality of unit filters having different light attenuation rates along the circumferential direction. Is disposed on the optical path of the reflected light so as to be rotatable about a rotation axis substantially parallel to the optical path, and attenuates the reflected light according to an attenuation rate of the unit filter in a portion irradiated with the reflected light. Claim 2 characterized by the above-mentioned. The mounted invention is the optical distance measuring device according to claim 1, wherein the rotary filter plate has a plurality of rotating filter plates, and each rotating filter plate is provided on an optical path of the reflected light and around a rotation axis substantially parallel to the optical path. The unit filters that are rotatably arranged independently of each other and that compose each of the rotary filter plates are selected from the plurality of rotary filter plates and select the unit filters one by one. It is characterized in that the total of the optical attenuation rates is different from the total of the optical attenuation rates of the unit filters of other combinations, and the invention according to claim 3 is the invention according to claim 1 or claim 2. The optical distance measuring instrument described above is characterized by further comprising rotation control means for rotating the filter plate so that the amount of light received by the light receiving means becomes a predetermined amount.

[0013]

The light emitted from the light emitting means is reflected by the reflecting means arranged at the measuring point to be reflected light, and the reflected light is received.
The phase delay is detected by comparing with the reference light, and the distance of the measuring point is obtained from the phase delay.

At this time, a light amount attenuating means is arranged so as to intersect with the optical path of the reflected light, and the light amount of the reflected light is attenuated into a transmitted light whose light intensity is almost equal to that of the reference light, and the transmitted light is received by the light receiving means. Receive light.

The light quantity attenuating means has a rotary filter plate provided with a plurality of unit filters having different light attenuation rates along the circumferential direction, and the rotary filter plate is provided on the optical path of the reflected light. Since they are arranged, if the size of the spot of reflected light is made smaller than the size of the unit filter, the reflected light is applied to one unit filter.

Further, since the rotary filter plate is arranged so as to be rotatable about a rotation axis which is substantially parallel to the optical path of the reflected light, when the rotary filter plate is rotated, the rotary filter plate can be adjusted according to the amount of the reflected light. A unit filter having an attenuation factor can be irradiated with the reflected light.

Furthermore, when a plurality of the rotary filter plates are prepared and the unit filters constituting the rotary filter plates are selected one by one from the rotary filter plates and combined,
It is configured such that the sum of the light attenuation rates of the unit filters associated with the combination and the value of the sum of the light attenuation rates of the unit filters associated with other combinations are different, and each rotary filter plate reflects the reflection. By arranging on the optical path of light so as to be rotatable independently of each other around a rotation axis that is substantially parallel to the optical path, it is possible to set many types of optical attenuation rates with a small number of unit filters.

Further, if rotation control means for rotating the filter plate is provided so that the amount of light received by the light receiving means becomes a predetermined amount, the amount of light received by the light receiving means is automatically set to an optimum value. can do.

[0019]

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

FIG. 1 is a block diagram of a lightwave distance measuring device according to an embodiment of the present invention. The lightwave distance measuring device includes a light emitting means 2 for generating an emitted light 3 and a light quantity of the irradiated light. A light amount attenuating means 4 for transmitting and attenuating, and a light receiving means 5 are provided.

When the emitted light 3 is reflected by a reflecting means (not shown) arranged on the measurement point, it becomes reflected light 6. The reflected light 6 enters the light quantity attenuating means 4, and becomes the transmitted light 7 with the light quantity attenuated and is received by the light receiving means 5.

The light quantity attenuating means 4 has a rotary filter plate 10 and comprises eight unit filters 11 _{1 to} 11 _8.
Are provided along the circumferential direction.

The light attenuation rates of the _eight unit filters 11 _{1 to} 11 ₈ are set such that the light attenuation rates increase in that order, and the unit filter 11 ₁ having the smallest attenuation rate has 0 dB, and the light attenuation rate has the highest. big unit filter 11 ₈ rate is such that 42 dB, and is configured to attenuation factor one by 6dB increases.

A motor 13 is attached to the rotary filter plate 10.
Is mounted by the motor 13 so as to be rotatable about a rotation axis 12 which is substantially parallel to the optical path.

The motor 13 is connected to a CPU 14 which is rotation control means, and the CPU 14 is connected to the light receiving means 5.

The rotary filter plate 10 is arranged on the optical path of the reflected light 6, and the amount of the reflected light 6 is
According to the light attenuation rate of the unit filter of the irradiated part,
Since the light is attenuated and incident on the light receiving means 5, the CPU 1
4 rotates the rotary filter plate 10 according to the light amount of the transmitted light 7 received by the light receiving means 5 and automatically adjusts the light amount of the transmitted light 7 so as to match the light amount of the reference light. Control.

Explaining this control, for example, first, the unit filter 11 ₁ is positioned on the optical path of the reflected light 6, and the light quantity of the reflected light 6 is measured. Next, the light amount and the light amount of the reference light are compared, and the CPU 14 rotates the motor 13 so that the light amount of the reflected light 6 becomes substantially equal to the light amount of the reference light. The rotary filter 10 is rotated so that a unit filter having a corresponding attenuation factor is located on the optical path of the reflected light 6. Specifically, for example, when the quantity of the reflected light 6 is 24 dB stronger than the quantity of the reference light serving as the reference, the unit filter 11 ₅ having an attenuation rate of 24 dB is located on the optical path of the reflected light 6. As described above, the rotary filter plate 10 is rotated so that the light amount of the transmitted light 7 and the light amount of the reference light coincide with each other.

FIG. 2 is a view for explaining an embodiment in which the light amount attenuating means has a plurality of rotating filter plates provided with a plurality of unit filters having different light attenuating rates as described above along the circumferential direction. FIG.

Referring to FIG. 2, in the light quantity attenuating means, two rotary filter plates 10 ₁ and 10 ₂ are arranged on the optical path of the reflected light 19 so as to be rotatable about the same rotation axis 18. The reflected light 19 is first reflected by the rotary filter plate 1
The transmitted light 20 is attenuated by 0 ₁ and then by the rotary filter plate 10 ₂ .

The rotary filter plate 10 ₁ is composed of eight unit filters 15 ₁ to 15 ₈ , and the rotary filter plate 10 ₂ is composed of eight unit filters 16 _{1 to} 16 ₈ , and The value obtained by summing the light attenuation rates of the two unit filters located on the optical path of the light 19 is the light attenuation rate of the light amount attenuation means.

The unit filters 15 ₁ to 15 ₈ are constructed so that the optical attenuation rate is sequentially increased by ₈ dB from 0 dB to 56 dB, and the unit filters 16 _{1 to} 16 ₈ are respectively changed from 0 dB to 0 dB. The optical attenuation rate is sequentially increased by 1 dB up to 7 dB.

The total number of the unit filters of the rotary filter plates 10 ₁ and 10 ₂ is 16, but a total of 64 combinations in which one unit filter can be selected from the rotary filter plates 10 ₁ and 10 _2. And from 0 dB to 63 dB
It is possible to obtain up to 64 different light attenuation factors. Therefore,
When 64 unit filters are provided on one rotary filter plate, the rotary filter plate becomes large and the entire apparatus becomes large.
Since 64 optical attenuation factors are set for 0 ₁ and 10 ₂ , the device can be downsized.

The rotary filter plates 10 ₁ , 10 ₂
Need not necessarily rotate about the same rotation axis, and any rotation filter plate may rotate about different rotation axes as long as they are located on the optical path of the reflected light 6.

[0034]

According to the present invention, it is possible to obtain an optical wave range finder having a simple structure and capable of improving measurement accuracy.

Further, it is easy to control the rotary filter plate.

[Brief description of drawings]

FIG. 1 is an embodiment of the present invention.

FIG. 2 is another example of the light amount attenuation means of the present invention.

FIG. 3 Prior art

[Explanation of symbols]

2 ... Light emitting means 3 ... Emitted light 4 ... Light amount attenuating means 5 ... Light receiving means 6, 19 ... Reflected light 7, 20 ...
... Transmitted light 12, 18 ... Rotation axis 10, 10 ₁ , 10 ₂ ... Rotation filter plate 11 _{1 to} 11 ₈ , 15 ₁ to 15 ₈ , 16 _{1 to} 16 ₈ ... Unit filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuyuki Matsumoto 260-63 Yanagicho, Hase, Atsugi, Kanagawa Prefecture Sokia Atsugi Factory (72) Inventor, Koji Sasaki 260-63, Yanagicho, Hase, Atsugi, Kanagawa Prefecture Stock Company Sokia Atsugi Factory

Claims (3)

[Claims] 1. A light emitting means for emitting emitted light, a light quantity attenuating means for transmitting and attenuating the light quantity of the emitted light, and a light receiving means, wherein the emitted light is a reflecting means arranged at a measuring point. Is a light wave rangefinder that measures the distance of a measurement point by attenuating the reflected light by the light amount attenuating means and receiving the light by the light receiving means, and the light amount attenuating means The rotary filter plate has a plurality of unit filters having different attenuation factors along the circumferential direction, and the rotary filter plate is provided on the optical path of the reflected light, around a rotation axis line substantially parallel to the optical path. An optical distance measuring device, which is rotatably arranged in the above position and attenuates the reflected light according to an attenuation rate of the unit filter in a portion irradiated with the reflected light. 2. A plurality of the rotary filter plates, each rotary filter plate being arranged on the optical path of the reflected light so as to be rotatable independently of each other around a rotation axis line substantially parallel to the optical path, The unit filters that make up the rotary filter plate are
When the unit filters are selected one by one from the plurality of rotary filter plates and combined, the total of the optical attenuation rates of the combined unit filters is different from the total of the optical attenuation rates of the unit filters of other combinations. The optical rangefinder according to claim 1, wherein the optical rangefinder is provided. 3. The rotation control means for rotating the filter plate so that the amount of light received by the light receiving means becomes a predetermined amount, and a rotation control means is provided. Lightwave rangefinder.