JP3763013B2 - Wide range detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a position detector that detects a precise position over a wide range by capturing a modulated laser beam diffused by transmission or reflection with a light receiving unit made of a plurality of semiconductors.
[ 0002 ]
[Prior art]
Conventionally, in vertical building, leveling, gradient standardization, straight line, etc. in indoor construction such as walls, pillars, floors, ceilings, and renovation work, laser beams can be visually recognized. Is used. On the other hand, since the laser beam is not visible in the daytime work outdoors in the bright surroundings, the purpose is to set the position in civil works such as construction work, civil engineering work (foundation work, land parcels, leveling, gutters, piping, etc.) As for, the beam by a laser beam is hardly utilized .
[ 0003 ]
However, in order to enable outdoor use, there is a method in which a laser beam is modulated and a laser beam is detected by a sensor . As the method, a semiconductor element is directly irradiated with a light beam, the semiconductor element is finely divided, and the position is detected by capturing the light beam with a number of high-sensitivity optical detectors provided for each of the semiconductor elements. Some have a four- divided element or a central electrode, and have electrodes on the left and right to detect the position of the light spot using the resistance difference between the left and right.
[ 0004 ]
When the modulated laser beam is captured by a semiconductor, the following problems and requirements arise.
(1) The center of the laser beam can be obtained accurately.
(2) In order to expand the working range, the beam of the laser beam is expanded to about 90 to 160 degrees, but the signal is weak and further decreases significantly with distance from the light source, so the dynamic range of the signal Therefore, not only about 60 dB or more is required, but almost the same center indication accuracy is required regardless of signal strength.
(3) Since it is easy to see in indoor use, in order to improve its workability, the laser beam is focused as a thin beam with a focal point of several millimeters, but the width of the beam goes farther away. Even if it is 2 to 3 mm in the vicinity, it becomes 30 mm or more in the distance, so the center indication accuracy cannot be ensured. In particular, since it is necessary to determine a position several tens of meters away as in outdoor work, in such a case, even if the beam width of the laser beam changes (regardless of distance), the center instruction is almost equivalent. Accuracy is required.
[ 0005 ]
[Problems to be solved by the invention]
Even if the beam width of the laser beam changes (regardless of the distance) in the outdoor work in the construction work, civil engineering work (foundation work, land division, leveling, gutter, piping, etc.) It is an object of the present invention to provide a wide-range position detector that can accurately obtain equivalent center indication accuracy and can efficiently perform a positioning operation.
[ 0006 ]
[Means for Solving the Problems]
The wide range position detector according to the present invention is:
In a position detector that includes a light receiving unit made of a plurality of semiconductors divided symmetrically in the left and right or / and up and down arranged in a laser irradiation region and that captures a modulated laser beam diffused by transmission or reflection by the light receiving unit ,
A light amount-voltage conversion circuit set to output the amount of modulated laser beam captured by the plurality of semiconductors as an AC signal, and to output an AC signal of the same value when the amount of light is the same intensity,
AC amplification means for amplifying each AC signal output from the light amount-voltage conversion circuit;
Compression means for compressing the dynamic range of each AC signal;
Rectifying means for converting each AC signal into a DC signal,
Differential amplification means for inputting each DC signal and outputting a difference between the input DC signals;
A differential output by the differential amplification means is input, and when the differential output is input, a window comparator that outputs a value determined by the width of the center width instruction voltage;
Inversion amplification means for changing the width of the center width indicating voltage of the window comparator to the strength of the DC signal by changing the center width indicating voltage given to the window comparator by the sum of each DC signal;
Cognitive means capable of audiovisual recognition corresponding to the output from the window comparator ;
It is characterized by comprising.
[ 0007 ]
【The invention's effect】
According to the wide range position detector according to the present invention configured as described above, the differential output by the differential amplifying means is input to the window comparator, and this is output at a value determined by the threshold width, and output. In response to the difference value, the alarm is reported at least at the equivalent position, so the beam can be viewed indoors as well as outdoor work where the beam is not visible. However, even if the beam width of the laser beam changes (regardless of distance), visual or auditory perception can be achieved, and almost equivalent center indication accuracy can be accurately obtained. In addition, the threshold width given to the window comparator is changed by the sum of the output from the rectifier and the inverting amplification means, so that the threshold width follows the signal strength. Therefore, the center indication accuracy is constant regardless of the strength of the signal.
[ 0008 ]
Accordingly, it is possible to provide a wide-range position detector that can perform operations such as positioning of a vertical line and a horizontal line by the irradiated light extremely efficiently.
[ 0009 ]
Example 1
A configuration circuit of a first embodiment of the wide range detector according to the present invention will be described with reference to FIG.
[ 0010 ]
First, a semiconductor PD ₁ in which a light beam from a laser light source set at a predetermined position is divided into two in the vertical direction of the phenomenon using the internal photoelectric effect (photovoltaic effect and photoconductive phenomenon) of a semiconductor (photodiode, etc.) _, This is detected by PD ₂ and connected to the light quantity-voltage conversion circuit (A ₁ ) (A ₂ ), and the voltage output at the same signal input is set equal.
[ 0011 ]
The output AC signals (modulated) are converted into DC signals by the AC amplifiers (A ₃ ) (A ₄ ), filters (A ₅ ) (A ₆ ) and rectifiers (A ₇ ) (A ₈ ). To the differential amplifier (A ₉ ) . The differential output from the differential amplifier (A ₉ ) is input to the window comparators (A ₁₀ ) (A ₁₁ ) . When a differential output is input, the window comparators (A ₁₀ ) and (A ₁₁ ) output a value determined by the width (threshold width) of the center width instruction voltages E ₁ to E ₂ .
[ 0012 ]
Corresponding to the output value from the window comparator (A ₁₀ ) (A ₁₁ ), _{one of} LED ₁ , LED ₂ , and LED ₃ is turned on under the control of the display driver or audio driver (U ₁ ) . LED ₃ is lit when the output value from the window comparator (A ₁₀₎ (A ₁₁₎ is zero value, in the case of positive value or a negative value, because the center of the vertical line is biased to either the left and right LED ₁ , LED ₂ lights up so that you can visually recognize which direction is biased . An operator manipulates the position of the position detector so that the LED ₃ is lit.
[ 0013 ]
When a vertical line is emitted using the wide-range position detector according to the first embodiment configured as described above, although not shown in the figure, for example, it is separated from a laser light source (hereinafter referred to as a vertical line irradiation unit) set at a predetermined position. Align the aiming mark of the semiconductor (photodiode PD _{1 ,} PD ₂ ) with the laser beam from the vertical line irradiation unit facing the target direction, and the laser irradiation position is LED ₁ , LED ₂ , the LED ₃ as a guide, rotated adjust the vertical line irradiation unit above LED ₃ is turned on, by determining the turn-on position of the LED ₃ as a line or a point of interest, positioning of the vertical line is accurately visually .
[ 0014 ]
Therefore, even if it is an outdoor work where the beam width of the laser beam is not visible, or at a position several tens of meters away, even if the beam width of the laser beam changes (regardless of distance) , Positioning work can be performed efficiently.
[ 0015 ]
If an extension line is required, move the light receiving unit (D) to the required distance from the laser irradiation unit and move it to find the position where LED ₃ lights up to determine the exact position on the extension line. To do.
[ 0016 ]
As shown in FIG. 2, the actual light input state is such that the intensity of light energy input to the semiconductors (photodiodes PD ₁ and PD ₂ ) divided in the left and right directions is PD ₁ > PD ₂ , PD ₁ >> PD When LED is ₂ , LED ₁ is lit. When PD ₁ << PD ₂ and PD ₁ <PD ₂ , LED ₂ is lit. When PD ₁ = PD ₂ , LED ₃ is lit. As a result, accurate positioning can be performed by searching for the position where the LED ₃ is lit.
[ 0017 ]
In this case, since only the output of the differential amplifier (A ₉ ) is truly zero when PD ₁ = PD ₂ , it is very difficult to install in a very narrow range during actual work. As described above, the output of the differential amplifier (A ₉ ) is input to the window comparator (A ₁₀ ) (A ₁₁ ), where the output is output within the range determined by the center width indicating voltages E ₁ and E _2. Therefore, the width E _{1 to} E ₂ of the center width instruction voltage may be set to a width that does not hinder practical use.
[ 0018 ]
When setting the horizontal reference line required for height positioning, use the horizontal line irradiation unit instead of the vertical line irradiation unit, and receive light so that the semiconductors PD ₁ and PD ₂ are vertically symmetrical. Similar to the case where the unit (D) is used to irradiate the vertical line, the light receiving unit (D) is used for the reference mark even in outdoor work where the laser beam is not visible. After fixing the LED ₃ of the unit (D) to the lighting range, find the height at which the LED ₃ lights up for each of the multiple light receiving units (D) arranged in the vertical direction, and the same height as the reference height Thus, the positioning of the horizontal line at a predetermined height is accurate, and therefore, it is possible to contribute to the efficient progress of the positioning operation.
[ 0019 ]
In any of the above cases, positioning was possible with an extremely high accuracy of ± 0.5 mm at a distance or height of 2.5 m and 10 m.
[ 0020 ]
(Example 2)
Wherein in the circuit of the light receiving unit (D) in Example 1, are window comparator (A ₁₀₎ (A ₁₁₎ to a given center width command voltage E ₁ ~ E ₂ of the width (the width of the threshold value) is constant . When the position of the laser beam changes with respect to PD ₁ and PD ₂ , the output per unit moving distance also becomes weak, and the center indication accuracy changes depending on the perspective .
[ 0021 ]
Therefore, as shown in FIG. 3, the circuit of the light receiving unit (D) according to the second embodiment has a width (threshold value) of the center width instruction voltages E _{3 to} E ₄ given to the window comparators (A ₁₀ ) (A ₁₁ ). Of the output from the rectifiers (A ₇ ) (A ₈ ) and the inverting amplifiers (A ₁₂ ) (A ₁₃ ) . That is, the width (threshold width) of the center width instruction voltages E ₃ to E ₄ is made to follow the strength of the signal. As a result, the center indication accuracy is constant regardless of the strength of the signal .
[ 0022 ]
Example 3
The beam width of the laser beam varies depending on the position of the determined focal point, but the degree of spread with respect to the distance changes, but once set, the ratio does not change. For example, if 2 mm at 5 m, 4 mm at 10 m, and 8 mm at 20 m, this is a change in distance and beam width, and at the same time, it can be treated as a correlation between light output and beam width. Therefore, the width (threshold width) of the center width command voltages E _{3 to} E ₄ may be controlled by (E _{3 to} E ₄ ) = (input light) ² .
[ 0023 ]
Therefore, in the wide-range position detector according to the third embodiment, as shown in the circuit of the light receiving unit (D) in FIG. 4, when the same signal is input to the X and Y inputs, the multiplication is such that the output is X × Y. Output to the window comparators (A ₁₀ ) and (A ₁₁ ) by means of inverting amplifiers (A ₁₂ ) and (A ₁₃ ) equipped with a circuit (U ₂ ).
[ 0024 ]
With the above circuit configuration, the beam width of the laser beam increases as the distance from the light source increases, but the center width instruction voltages E _{3 to} E ₄ controlled by the circuit of the light receiving unit (D) in the second embodiment. Can be further reduced in inverse proportion to the distance, so that the center indication accuracy can be the same regardless of the beam width.
[ 0025 ]
Further, the change in the beam width of the laser beam means that the energy density in the position detection direction in FIG. 2 changes and the output of the differential amplifier (A ₉ ) per unit movement amount also changes. For example, if the beam width is 1 mm and the output of the differential amplifier (A ₉ ) changes by ± 1 V when the beam width is 2 mm, if the beam width is 2 mm, the differential amplifier (A ₉ ) This is because the output does not change by ± 1V.
[ 0026 ]
(Example 4)
Furthermore, although not shown in the drawings, when the width of the light receiving unit (D) in the position detection direction of the semiconductors PD ₁ and PD ₂ or the width of the light input opening with respect to the semiconductors (PD ₁ and PD ₂ ) is made smaller than the beam width Since the light output decreases in inverse proportion to the beam width, calculating the ratio when the distance is 10 m is set to 1, the beam width, which is a variable, is automatically set to a ratio proportional to the distance. For the optical input, the ratio of the center width instruction voltage E ₃ to the ratio of the width (threshold width) of the center width instruction voltages E _{1 to} E ₂ to be controlled is combined with the fact that the ratio can be made inversely proportional to the distance. Since a result is obtained in which E ₄ is a ratio of the square of the light input ratio and the detection accuracy can be made extremely excellent, this is disclosed as Example 4.
[ 0027 ]
(Example 5)
In each of the first to fourth embodiments, the case where a two-part semiconductor (PD ₁ , PD ₂ ) is used has been described. In this case, as apparent from FIG. 5, the beam width of the laser beam is the semiconductor. Even when PD ₁ and PD ₂ are in the diagonal direction, PD ₁ = PD ₂ and LED ₃ in the case of a vertical line may be lit, so the light receiving unit (D) itself has a level indicator such as a bubble tube, It is necessary to provide a tilt sensor (S) such as a horizontal axis sensor and adjust the position while confirming this to avoid misrecognition.
[ 0028 ]
In such a case, as shown in FIG. 5, the semiconductor PD ₁ , PD ₂ , PD ₃ , PD ₄ can be obtained by using a semiconductor that is symmetrically divided into left and right and up and down as the light receiving unit (D). PD ₂ + PD ₃ = PD ₁ + PD ₄ unless the center of the beam width of the laser beam is on the diagonal passing through the semiconductor intersection. Therefore, accurate positioning work is required without using a bubble tube. The circuit of the light receiving unit (D) is configured according to the circuit of each of the above embodiments. In this case, it is not limited to the above four divisions, and may be five divisions or more, but is preferably a sufficient division or less from the viewpoint of cost and the like, and the circuit is configured in accordance with the four division circuit.
[ 0029 ]
In addition, although the circuit control of the light receiving unit (D) can be performed by analog calculation, the circuit becomes complicated. As shown in FIG. 6, each input is input to the CPU after A / D conversion, and the light intensity is , Beam width calculation, threshold value determination, horizontal beam and vertical beam identification, tilt sensor beam tilt instructions are all softwareized and output by the display driver, LED ₁ , LED ₂ , LED ₃ (left side) LED ₄ , LED ₅ , LED ₆ (left tilt, horizontal, right tilt) LED ₇ , LED ₈ (vertical line input, horizontal line input) are preferably lit.
[ 0030 ]
According to the wide range position detectors according to the first to fifth embodiments described above, the intensity ratio of the signal output from the voltage conversion circuit for the light amount of the laser beam captured by the light receiving unit at the short distance and the long distance is the beam width. Considering the spread, angle, etc., the maximum is expected to be about 10,000: 1, and this intensity ratio can be directly input to the linear amplifier for amplification processing, but at the same time, special consideration is required for each circuit.
[ 0031 ]
For example, when the change in signal strength is large, it is necessary to consider using a normal AGC (automatic gain adjustment) circuit as shown in FIG. This circuit amplifies the signal from the filters (A ₅ ) and (A ₆ ) by a gain control amplifier (A ₁₄₀ ), rectifies it, and then uses a comparison / feedback circuit to increase the gain corresponding to the small and large output signals. Although it is configured by a circuit that secures a signal at a certain level by raising and lowering it, it is unavoidable that a time constant exists in the circuit itself because it involves rectification and feedback.
[ 0032 ]
In the following embodiments according to the present invention, considering that the wide-range position detector according to the first to fifth embodiments becomes an unstable output state from a minute output to a high accuracy due to a constant change of the parts used, Wide range position detector that uses compression means that essentially does not require a feedback circuit, compresses the dynamic range of the signal so that the output level does not change significantly, and increases the speed and followability of the signal. It is what.
[ 0033 ]
Although compression is possible with various functions, in the conversion example in which the output from the voltage conversion circuit is input to the logarithmic conversion circuit, the difference in input versus output from the linear amplifier is as follows.
Input Linear (proportional) output (V) Logarithmic output 1 1 1
1/10 1/10 0.8
1/100 1/100 0.6
1/1000 1/1000 0.4
1/10000 1/10000 0.2
[ 0034 ]
As is clear from this example, linear (proportional) output requires very little to high accuracy, but logarithmic output requires few feedback levels and is easy to handle. AC signal that is a wide-range position detector that compresses the dynamic range of the signal so that the output level does not change greatly, and improves the signal speed and good tracking performance. The sixth embodiment, the seventh embodiment, the eighth embodiment in which rectification and compression are simultaneously performed in the rectifier circuit, and the ninth embodiment in which compression is performed after direct current conversion will be described in order.
[ 0035 ]
(Example 6)
As shown in FIG. 8, the wide range position detector according to the sixth embodiment includes an AC amplifier (A ₃ ) (A ₄ ) and filters (A ₅ ) (A ₆ ) in the configuration circuit of FIG. 1 shown as the first embodiment. In between, the logarithmic compressor (A ₁₄ ) (A ₁₅ ) that compresses the dynamic range of the AC signal is interposed to compress the dynamic range of the signal and increase the speed of the signal so that the output level does not change greatly. The description of the other parts of the circuit overlaps with the description of the first embodiment and is omitted. FIG. 9 shows an example of a circuit (AD8307) of logarithmic compressors (A ₁₄ ) (A ₁₅ ) as AC signal compression means interposed between the AC amplification means and the rectification means.
[ 0036 ]
(Example 7)
As shown in FIG. 10, the wide range position detector according to the seventh embodiment removes noise when the logarithmic compressors (A ₁₄ ) (A ₁₅ ) for compressing the dynamic range of the AC signal are interposed in the sixth embodiment. In consideration , the filters (A ₁₆ ) (A ₁₇ ) and the gain adjusting means (A ₁₈ ) (A ₁₉ ) are installed between the filters (A ₅ ) (A ₆ ) and the rectifiers (A ₇ ) (A ₈ ). A connection is interposed.
[ 0037 ]
(Example 8)
As shown in FIG. 11, the wide range position detector according to the eighth embodiment amplifies the AC signal output from the light amount-voltage conversion circuit (A ₁ ) (A ₂ ) by the AC amplifier (A ₃ ) (A ₄ ). Filter (A ₅ ) (A ₆ ), which is converted into a DC signal by rectifier means, and the dynamic range of the signal is compressed by a logarithmic compressor (A ₁₄ ) (A ₁₅ ), and then differential amplification a broad position detector which is adapted to enter the differential output by means window comparator, the filter (a ₅₎ with respect to the output from (a _6), the rectifier and simultaneously logarithmic compressor compression (a ₁₄₎ (a ₁₅ ).
[ 0038 ]
As a logarithmic compressor (A ₁₄ ) (A ₁₅ ) in this case, as shown in FIG. 12, a circuit composed of a combination of a buffer, a diode and a smoothing capacitor is used, which is a forward current at the PN junction of the diode − The forward voltage shows a logarithmic characteristic, and the larger the signal, the more the amplitude is compressed in the positive direction, and the fact that the signal does not appear because the current does not flow at the negative amplitude.
[0039]
Example 9
As shown in FIG. 13, the wide-range position detector according to the ninth embodiment uses an AC amplifier (A ₃ ) to output an AC signal output from the light amount-voltage conversion circuit (A ₁ ) (A ₂ ) as shown in FIG. ) (A ₄ ), a filter (A ₅ ) (A ₆ ), and a rectifier (A ₇ ) (A ₈ ), and then converting the DC signal dynamic range to a logarithmic compressor (A ₁₄ ) (A ₁₅ ), And the differential output from the differential amplifier (A ₉ ) measures the value of the amount to be controlled by the control system, and continuously compares the amount with the target value (A ₁₀ ) ( This is input to A ₁₁ ) and output with a value determined by the threshold width.
[ 0040 ]
The logarithmic compressors (A ₁₄ ) and (A ₁₅ ) are examples of DC signal compression means, and are the same as the logarithmic compression circuit (ICL8048) shown in FIG. This is the same as the other embodiments in that the signal is compressed so as not to change greatly, and the speed of the signal is increased and the followability is good, and the description of each part of the other circuits overlaps the description of the third embodiment. Omitted.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram of a wide-range position detector according to a first embodiment.
FIG. 2 is a diagram illustrating an actual light input state to the light receiving unit (D) of the wide-range position detector according to the first embodiment.
3 is a circuit configuration diagram of a wide range position detector according to Embodiment 2. FIG.
4 is a circuit configuration diagram of a wide range position detector according to Embodiment 3. FIG.
FIG. 5 is a diagram illustrating an actual light input state to the light receiving unit (D) of the wide-range position detector according to the fifth embodiment.
FIG. 6 is a block circuit diagram of a four-divided semiconductor and CPU processing.
FIG. 7 is a normal AGC (automatic gain adjustment) circuit.
FIG. 8 is a circuit configuration diagram of a wide range position detector according to a sixth embodiment.
FIG. 9 shows a circuit (AD8307) of a logarithmic compressor (A ₁₄ ) (A ₁₅ ) which is an example of AC signal compression means.
FIG. 10 is a circuit configuration diagram of a wide range position detector according to a seventh embodiment.
FIG. 11 is a circuit configuration diagram of a wide range position detector according to an eighth embodiment.
FIG. 12 is a circuit diagram including a combination of a buffer, a diode, and a smoothing capacitor used as compression means.
FIG. 13 is a circuit configuration diagram of a wide range position detector according to a ninth embodiment.
FIG. 14 shows a circuit (ICL8048) of a logarithmic compressor (A ₁₄ ) (A ₁₅ ) which is an example of DC signal compression means.
[Explanation of symbols]
PD _{1 to} PD ₄ photodiodes
(D) Receiver unit
(A ₁ ) (A ₂ ) Light quantity-voltage conversion circuit
(A ₃ ) (A ₄ ) AC amplifier
(A ₅ ) (A ₆ ) Filter
(A ₇ ) (A ₈ ) Rectifier
(A ₉ ) Differential amplifier
(A ₁₀ ) (A ₁₁ ) Window comparator
(U ₁ ) Audio driver
(U ₂ ) multiplier
(A ₁₂ ) (A ₁₃ ) Inverting amplifier
(A ₁₄ ) (A ₁₅ ) Logarithmic compressor
(A ₁₆ ) (A ₁₇ ) Filter
(A ₁₈ ) (A ₁₉ ) Gain adjustment means

Claims (1)

In a position detector that includes a light receiving unit made of a plurality of semiconductors divided symmetrically in the left and right or / and up and down arranged in a laser irradiation region and that captures a modulated laser beam diffused by transmission or reflection by the light receiving unit ,
A light amount-voltage conversion circuit set to output the amount of modulated laser beam captured by the plurality of semiconductors as an AC signal, and to output an AC signal of the same value when the amount of light is the same intensity,
AC amplification means for amplifying each AC signal output from the light amount-voltage conversion circuit;
Compression means for compressing the dynamic range of each AC signal;
Rectifying means for converting each AC signal into a DC signal,
Differential amplification means for inputting each DC signal and outputting a difference between the input DC signals;
A differential output by the differential amplification means is input, and when the differential output is input, a window comparator that outputs a value determined by the width of the center width instruction voltage;
Inversion amplification means for changing the width of the center width indicating voltage of the window comparator to the strength of the DC signal by changing the center width indicating voltage given to the window comparator by the sum of each DC signal;
Cognitive means capable of audiovisual recognition corresponding to the output from the window comparator ;
A wide-range position detector characterized by comprising:

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