JPH064249Y2 - Optical distance measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical distance measuring device that irradiates an object to be measured with a light beam and uses the reflected light to measure the distance to the object to be measured.

BACKGROUND ART Conventionally, there is an optical distance measuring device of this type as shown in FIG. That is, the light projecting element 1 and the light projecting lens system 2 form a light projecting means for projecting a light beam onto the measured object 3, and the light receiving lens system receives the reflected light of the light spot formed on the measured object 3. The light receiving means is formed by the light receiving element 5 including the four and one-dimensional position detecting elements. The light receiving means is arranged on the side of the light projecting means at a predetermined interval, and the light spot is imaged on the light receiving element 5. .
The light spot imaged on the light receiving element 5 moves as a ′ → b ′ → c ′ in FIG. 3 when the measured object 3 moves a → b → c in FIG. It has become. That is, the distance from the measured object 3 becomes clear by knowing the position of the light spot on the light receiving element 5. The light receiving element 5 is a one-dimensional position detecting element (for example, a PSD element manufactured by Hamamatsu Photonics KK) that detects the position of the light spot as described above, and outputs the output currents i ₁ and i corresponding to the position of the light spot. Outputs ₂ (opposite currents). Both output currents i ₁ and i ₂ output from the light receiving element 5 are input to the subtractor 6 and the adder 7, respectively (v ₁ −
v ₂ ) and (v ₁ + v ₂ ) are calculated. After that, by calculating (v ₁ −v ₂ ) / (v ₁ + v ₂ ) using the divider 8, a voltage value corresponding to the distance can be obtained regardless of the amount of received light. That is, triangulation distance measurement is performed, and FIG. 4 is a diagram showing the relationship between the output of the divider 8 and the distance. As is clear from this figure, the distances a, b, c of the measured object 3 are obtained corresponding to the outputs a ″, b ″, c ″ of the divider 8. Therefore, this divider By setting the comparator 9 in the subsequent stage of 8,
It is possible to easily determine whether the measured object 3 is closer or farther than d _T , and for example, the object detection signal V _O indicating that the measured object 3 exists within the predetermined distance d _T. Is output to the output terminal O ₂ via the output circuit 12. That is, in FIG. 4, if the threshold voltage _VT is set by the threshold voltage setting circuit 9a, the distance of the measured object 3 based on the set distance d _T is determined and the determination result is output. ing. The output of the divider 8 is output to the output terminal O ₁ via the analog output circuit 11 as a distance measurement signal V ₁ (DC voltage according to distance). Furthermore, the output of the adder 7 is input to the light-reception level determination circuit 12, and the light-reception level determination means 12 determines whether the amount of received light is excessive or the amount of received light is excessively small, and the determination result is obtained. The abnormality determination signals Vb and Vd are output to the output terminals O ₃ and O ₄ via the output circuit 13 and the determination result is displayed on the display circuit 14. That is, when the amount of received light is greater than the preset bright level, it is determined that the light receiving amplifier is saturated and the accurate distance is not measured, and the excessive determination signal Vb is output via the output terminal O _3. At the same time, the light emitting diode L ₁ is turned on. On the other hand, when the amount of received light is smaller than the preset dark level, it is determined that the calculation accuracy of the divider 8 is lowered and an accurate distance is not measured. Output the underdetermination signal Vd via the output terminal O ₄ , and
The light emitting diode L ₂ is turned on to display that effect. However, in such a conventional example, the light reception level determination circuit 12 outputs the determination results of the received light amount to the output terminals O ₃ and O ₄ , respectively, but the distance measurement signal Vl is output. Output terminal O ₁
Through the output terminals O ₃ and O ₄ which are different from
Since each d is output, the user can
_In the case of monitoring the distance measurement signal Vl output from _{No. 1} , it is necessary to constantly monitor the abnormality determination signals Vb and Vd output from the other output terminals O ₃ and O ₄ to perform logical processing. There is a problem that the output wiring to the device becomes complicated and the configuration of the logic circuit in the signal processing circuit becomes complicated. Further, since the output terminals O ₁ , O ₂ , O ₃ , and O ₄ are provided corresponding to the respective output signals, there is a problem that the occupied space of the output terminal portion becomes large and the size cannot be reduced.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to simplify the output wiring to the signal processing circuit and the circuit configuration of the signal processing circuit, and to provide the number of outputs. An object of the present invention is to provide an optical distance measuring device that can reduce the number of devices and can be easily downsized.

DISCLOSURE OF THE INVENTION (Embodiment 1) FIG. 1 shows an embodiment of the present invention, in which a light projecting means for projecting a light beam onto an object 3 to be measured and a predetermined side surface of the light projecting means. A light receiving unit which is arranged at a distance to receive the reflected light from the measured object 3; a distance measuring circuit 10 which measures the distance to the measured object 3 based on the position of the light spot received by the light receiving unit; The light receiving level determination circuit 12 for determining whether the amount is too large or too small, and the distance measuring signal Vl output as a voltage level signal from the distance measuring circuit 10 and the abnormality output from the light receiving level determining circuit 12. In the same optical distance measuring device as in the conventional example in which the determination signals Vb and Vd are output via the output terminals, a common output terminal O ₁ for outputting the distance measurement signal Vl and the abnormality determination signals Vb ′ and Vd ′ is provided. Provided and received light level Circuit 1
When the abnormality determination signals Vb and Vd are output from the output terminal 2, the signal switching circuit 15 that stops the output of the distance measurement signal Vl and outputs the abnormality determination signals Vb 'and Vd' is provided, and the abnormality determination signals Vb 'and Vd'
Is set to a predetermined voltage outside the voltage level fluctuation range of the distance measurement signal Vl. In the embodiment, since the voltage level fluctuation range of the distance measurement signal Vl is + 5V to -5V, the abnormality determination signal Vb ′ And Vd ′ are + 10V (excessive determination signal Vb),
It is set to -10 V (underdetermination signal Vd). Note that other configurations and operations are the same as those of the conventional example.

The operation of the embodiment will be described below. Now, the amount of light received by the light receiving means is within the normal range, and the adder 7
When the output is within the preset range, the light receiving level determination circuit 12 does not output the abnormality determination signals Vb and Vd, so that the signal switching circuit 15 outputs the distance measurement signal Vl output from the divider 8. Is output to the common output terminal O ₁ via the analog output circuit 11, and the operation is exactly the same as the conventional example. On the other hand, when the amount of light received by the light receiving means deviates from the normal range and the output of the adder 7 becomes larger or smaller than the preset range, the light receiving level judgment circuit 12 judges that it is excessive. The signal Vb or the underdetermination signal Vd is output, and the signal switching circuit 15 stops the output of the distance measurement signal Vl output from the divider 8 and outputs the abnormality determination signals Vb ', Vd' (+ 10V or -10).
V) via the analog output circuit 11 to the common output terminal O ₁
It is designed to output from.

Therefore, the signal processing circuit on the user side can determine whether or not the distance measuring operation is normally performed only by measuring the signal level of the common output terminal O ₁ , and when no abnormality occurs, that is, the output signal voltage. Is + 5V to -5V
In this case, the output signal voltage can be processed as the distance measurement signal Vl, and the output wiring to the signal processing circuit and the circuit configuration of the signal processing circuit can be simplified. The common output terminal O ₁ of the ranging signal Vl and the abnormality determination signal Vb ', Vd' so is output, it is possible to reduce the number of terminals as compared with the prior art, is less occupied space of the output terminal portion Therefore, the size can be easily reduced.

(Embodiment 2) FIG. 2 shows another embodiment, in which a signal switching circuit 15a added with an OR circuit OR for calculating the logical sum of the abnormality determination signals Vb and Vd output from the light receiving level determination circuit 12 is shown. Provided, when any of the abnormality determination signals Vb, Vd are obtained,
The abnormality determination signal Vbd having a predetermined voltage (for example, +10 V) is output from the common output terminal O ₁ , and other configurations and operations are the same as those in the first embodiment.

[Advantage of the Invention] As described above, the present invention provides a light projecting means for projecting a light beam to an object to be measured and a light reflected from the object to be measured, which is arranged at a side of the light projecting means at a predetermined interval. Consists of a light-receiving means for receiving light, a distance-measuring circuit for measuring the distance to the object to be measured based on the position of the light spot received by the light-receiving means, and a light-receiving level judgment circuit for judging whether the amount of received light is excessive or excessive In the optical distance measuring device, the distance measurement signal output as a voltage level signal from the distance measurement circuit and the abnormality determination signal output from the light receiving level determination circuit are output via the output terminals. A common output terminal for outputting the distance measurement signal and the abnormality determination signal is provided, and when the abnormality determination signal is output from the light receiving level determination circuit, the output of the distance measurement signal is stopped and the abnormality determination signal is output. A signal switching circuit is provided, and the abnormality determination signal is set to a predetermined voltage outside the voltage level fluctuation range of the distance measurement signal.
Since the distance measurement signal and the abnormality determination signal are output via the common output terminal, the output wiring to the signal processing circuit and the circuit configuration of the signal processing circuit can be simplified, and the number of terminals can be reduced, and the size is small. Even if the distance measurement signal and the abnormality determination signal are output from the common output terminal, the abnormality determination signal generated when the amount of received light is too large or too small is The voltage of the abnormality determination signal does not overlap with the voltage variation range of the distance measurement signal because it is set to a predetermined voltage outside the voltage level variation range of, and the distance measurement signal and the abnormality determination signal can be determined only by the voltage level. This has the effect of being able to reliably identify.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an essential part of one embodiment of the present invention, FIG. 2 is a block circuit diagram of an essential part of another embodiment, FIG. 3 is a block circuit diagram of a conventional example, and FIG. FIG. 1 is a light projecting element, 2 is a light projecting lens system, 3 is an object to be measured, 4
Is a light receiving lens system, 5 is a light receiving element, 10 is a distance measuring circuit, 12
Is a light receiving level determination circuit, and O ₁ is an output terminal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shintaro Yamamoto, 1048 Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works, Ltd. (72) Mao Asai, 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works, Ltd. (56) ) References JP-A-62-81520 (JP, A) Actually developed Shou 60-143306 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A light projecting means for projecting a light beam onto an object to be measured, a light receiving means arranged at a side of the light projecting means at a predetermined interval to receive reflected light from the object to be measured, and a light receiving means. It consists of a distance measuring circuit that measures the distance to the object to be measured based on the position of the light spot received at, and a light receiving level determination circuit that determines whether the received light amount is too large or too small. In the optical distance measuring device that outputs the distance measurement signal output as a signal of the corresponding voltage level and the abnormality determination signal output from the light receiving level determination circuit through the output terminal, the distance measurement signal and the abnormality determination signal In addition to providing a common output terminal for outputting, the signal switching circuit that stops the output of the distance measurement signal and outputs the abnormality determination signal when the abnormality determination signal is output from the received light level determination circuit is provided. Optical distance measuring apparatus characterized by setting the constant signal to a voltage level variation range of a predetermined voltage ranging signal.