JP2001272206A - Object position measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object position measuring apparatus, which enables highly accurate measurement of the position of an object with a simple structure in a type which measures the position of the object utilizing an optical sensor. SOLUTION: The base structure of the object position measuring apparatus comprises a sensor unit 1, which transmits scanning light to a measuring area to detect the position of an object in the measuring area, bases on the reception state of the reflected light and a reflection part 23, which enables recurrent reflection of the scanning light transmitted from the sensor unit 1. The sensor unit 1 has a stably laser light scanning part 10, which makes a laser light scan with a fixed amplitude using a resonance type mirror to be sent to the reflection part 2, a received waveform processing part 30 to detect the light or the like recurrently reflected by the reflection part 2 and an object position detecting part 50 to detect the position of the object in the measuring area, based on information pertaining to the direction of scanning light at a stable laser light scanning part 20 and the received waveform at the received waveform processing part 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the position of an object using an optical sensor, and more particularly, to scanning light emitted from a light source using a resonance type mirror and receiving the reflected light. The present invention relates to an object position measurement device that performs measurement based on a state.

[0002]

2. Description of the Related Art As a conventional object position measuring apparatus, for example, an apparatus described in Japanese Patent Application Laid-Open No. 9-51969 is known. This conventional apparatus forms an optical sensor net by arranging a plurality of pairs of a light emitter (light emitting element) and a light receiver (photodiode) in the horizontal and vertical directions.
Detecting that the optical axis is blocked by passing an object,
It detects the passage timing and position of an object.

For example, in an apparatus described in Japanese Patent Application Laid-Open No. 11-63916, light projected from one side is reflected to an object, and the object is detected by receiving the reflected light. Technology has been proposed.

Further, for example, in a hit ball determination sensor described in Japanese Patent Application Laid-Open No. Hei 7-31711, a flat light beam emitted from a laser line marker is converted into a light receiver group arranged over a light receiving range in a spreading direction thereof. There is disclosed a technique for measuring a passing position of an object by receiving light and detecting light blocking caused by passing of the object.

[0005]

However, the conventional object position measuring device as described above needs to provide a large number of light emitters and light receivers according to the size of the area for measuring the passing position of the object. There is a problem that the device configuration becomes complicated.

[0006] Specifically, Japanese Patent Application Laid-Open No. 9-51969 describes the above.
In each of the devices described in Japanese Patent Application Laid-Open No. 11-63916 and Japanese Patent Application Laid-Open No. 11-63916, it is necessary to arrange a plurality of light emitters and a plurality of light receivers according to the measurement area. Also, JP-A-7-3
In the device described in Japanese Patent No. 1711, only one light emitting device is required on the light emitting side for one measurement area, but it is necessary to arrange a plurality of light receiving devices corresponding to the measurement resolution on the light receiving side. Was.

The present invention has been made in view of the above problems, and has as its object to provide an object position measuring device capable of measuring the position of an object with high accuracy by a simple configuration.

[0008]

In order to achieve the above object, an object position measuring apparatus according to the present invention irradiates a movable mirror with light emitted from a light source and scans a predetermined measurement area with a scanning light. Light scanning means for generating light, light reflection means arranged to face the light scanning means, and capable of retroreflecting the scanning light sent from the light scanning means, and arranged near the light scanning means A light receiving unit that receives the light retroreflected by the light reflecting unit; a light scanning direction of the light scanning unit; and a light receiving state in the measurement area based on a change in a light receiving state of the light receiving unit. And an object detecting means for detecting the position of the object.

In this configuration, the light from the light source is reflected by the movable mirror and is transmitted from the light scanning means to the light reflecting means so as to scan the inside of the measurement area. The scanning light that has reached a required portion of the light reflecting means is retroreflected in a direction substantially along the incident direction, and is received by a light receiving means arranged near the light scanning means. When an object is present in the measurement area, the light receiving state of the light receiving means changes when the scanning light reaches the position of the object. Therefore, the change in the light receiving state and the scanning angle at that time are monitored by the object detecting means. The position (direction) of the object in the measurement area
Will be detected. Thus, one light source and one light source
With a simple configuration using two light receiving means, it becomes possible to measure the position of an object in a required measurement area.

It is preferable that the optical scanning means of the object position measuring device uses a resonant mirror driven by using an electromagnetic force as a movable mirror. Specifically, this resonance type mirror is provided with a mirror and a coil on the surface of a movable plate pivotally supported via a torsion bar, while a magnetic field is applied to a coil portion parallel to the axial direction of the torsion bar. May be provided, and the coil may be supplied with an alternating current for driving the movable plate to swing the movable plate.

With this configuration, the light from the light source is periodically scanned according to the swing of the resonance mirror.
Further, as a specific configuration of the object position measuring device, the light scanning means scans light from the light source on a straight line, and the light reflection means scans light emitted from the light scanning means. A retroreflection unit may be provided at the center of the scanning range excluding both ends of the scanning range. Alternatively, the light reflecting means may include a retroreflecting part arranged at each end of the scanning range with respect to the scanning range of the light transmitted from the optical scanning means.

With this configuration, the light receiving state of the light receiving means greatly changes between when the scanning light is located at both ends of the linear scanning range and when it is located at the center. That is, when the retroreflecting portion of the light reflecting means is arranged at the center of the scanning range, most of the scanned light is retroreflected by the light receiving means unless an object exists in the measurement area. The light is received. On the other hand, when the retroreflectors are arranged at both ends of the scanning range, when light is scanned at both ends of the scanning range or an object position in the measurement area, the reflected light is received by the light receiving means. Become so.

[0013] In the object position measuring device in which the retroreflective section is arranged as described above, the light scanning means generates light in response to light from the light source being scanned at one end of a scanning range. Based on a change in the light receiving state of the light receiving means, has a scanning origin detection unit that identifies the origin of the periodic optical scanning,
The object detection unit detects an object existing in the measurement area based on an elapsed time after the scanning light has passed through the scanning origin specified by the scanning origin detection unit and a change in a light receiving state of the light receiving unit. The scanning angle corresponding to the position may be detected.

In such a configuration, based on the change in the light receiving state that occurs when light is scanned at both ends of the scanning area, the time when one end is scanned with light is specified as the scanning origin, and the scanning origin is determined. The position of the object in the measurement area is detected based on the elapsed time after passing.

In addition, the light scanning means of the above-described object position measuring device monitors the light scanning range based on the light receiving state of the light receiving means, and drives the resonance type mirror so that the scanning range becomes constant. An automatic amplitude adjuster for controlling the state may be provided.

In this configuration, the scanning range of the light emitted from the optical scanning means is automatically controlled to be constant, so that the position of the object can be measured stably. The object position measuring device has a plurality of sensor units each including the optical scanning unit, the light receiving unit, and the object detecting unit, and the sensor units each include a scanning range of scanning light overlapping each other. Calculating means for calculating the coordinates of the object in the measurement area based on the position of the object detected by at least two of the plurality of sensor units; You may make it comprise.

In this configuration, the object in the measurement area is detected by at least two of the plurality of sensor units, and the positions (directions) of the objects detected by the sensor units are combined. , The coordinates of the object in the measurement area can be calculated.

Further, as a specific configuration of the above-mentioned object position measuring device, there are first and second light reflecting means opposed to a reflecting surface, and two or more light reflecting means are provided so as to face the first light reflecting means. Disposing the sensor unit, disposing the two or more sensor units facing the second light reflecting means,
A planar measurement area may be formed between the first and second light reflecting means.

Further, the object position measuring device using a plurality of sensor units has first and second light reflecting means and third and fourth light reflecting means which are opposed to the reflecting surface. Two or more sensor units are arranged so as to face one light reflecting means, and two or more sensor units are arranged so as to face the second light reflecting means, and the first and second light reflecting means are arranged. A first measurement area is formed between the two, and two or more sensor units are arranged so as to face the third light reflection means, and two or more sensor units are arranged so as to face the fourth light reflection means. A sensor unit is arranged to form a planar second measurement area between the third and fourth light reflection means, and the first measurement area and the second measurement area are
The position of the object and the passage time of the object calculated with respect to the first measurement area, and the position and the object of the object calculated with respect to the second measurement area, which are arranged substantially in parallel at a predetermined interval. Based on the time of passage
Information on the moving state of the object may be calculated.

In such a configuration, the position of the moving object is detected in each of the first measurement area and the second measurement area together with each passing time, and by combining the detection results in each measurement area, the movement of the moving object is determined. It becomes possible to calculate information on the moving state such as the direction and speed of the moving object.

Further, with respect to each sensor unit of the object position measuring device using a plurality of sensor units, each of the sensor units sends out scanning light modulated at a different frequency from each other, and outputs the scanning light modulated by the light receiving means. It is desirable to identify whether or not it is the reflected light of the scanning light transmitted by itself based on the modulation frequency. Alternatively, the light reflecting means may be arranged such that a normal direction of the reflecting surface is at an angle to a scanning plane formed by the scanning light.

With this configuration, mutual interference between the sensor units can be avoided, and more accurate object position measurement can be performed. In addition, for each sensor unit of the above-described object position measuring device, it is preferable that the tangent value of the scanning angle be set in advance in each object detecting means as angle data.

In such a configuration, the tangent of the scanning angle (ta)
n) By setting the value in the object detection means in advance, the calculation processing of the coordinates in the calculation means can be performed only by addition, subtraction, multiplication and division of the tan value, thereby enabling high-speed calculation processing.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of the object position measuring device according to the first embodiment. Also,
FIG. 2 is a perspective view showing an appearance of the object position measuring device of FIG.

In FIG. 1 and FIG. 2, the present object position measuring device is, for example, a sensor unit 1 for measuring the position of an object by receiving reflected return light of scanning light sent to the outside.
And a reflection unit 2 as light reflection means, and a sensor unit 1
And a display unit 4 for displaying the measurement result to the outside. However, FIG.
Here, illustration of the control unit 3 and the display unit 4 is omitted.

The sensor unit 1 has a stable laser beam scanning section 10 as an optical scanning section, a light receiving waveform processing section 30 as a light receiving section, an object position detecting section 50 as an object detecting section, and a sensor control section 70.

The laser beam stable scanning section 10 has a function of scanning the laser beam stably in accordance with the measurement range of the object. Specifically, a laser beam emitted from a semiconductor laser 11 as a light source is scanned by the optical scanning unit 12 and transmitted to the reflecting unit 2. The semiconductor laser 11 is a general light source that generates laser light of a required wavelength, and is driven by an output signal from a laser modulation control unit 13.
The laser modulation control unit 13 generates a laser drive signal synchronized with the clock signal CLK from the crystal oscillator OS. This laser drive signal is modulated at a preset frequency, and is output to the semiconductor laser 11 in response to a laser lighting instruction from the sensor control unit 70. The above-described crystal oscillator OS has a constant cycle T _CLK (frequency f _CLK = 1 / T
_CLK ) is generated.

Although not shown, the optical scanning section 12 includes a movable mirror for scanning laser light from the semiconductor laser 11 and a driving circuit for the movable mirror. As the movable mirror, for example, a resonance type mirror driven by using an electromagnetic force is suitable. Specifically, it is preferable to use a semiconductor galvanomirror manufactured by using the micromachining technology previously proposed by the present applicant (JP-A-7-175).
005 and JP-A-7-218857).

Here, the basic configuration of the semiconductor galvanometer mirror will be briefly described. For example, as shown in FIG. 3, a semiconductor galvanometer mirror includes a torsion bar 102 and a torsion bar 10 inside a silicon substrate 101.
And the movable plate 103 supported by the silicon substrate 10
1, a planar coil 104 is provided on the upper surface of the movable plate 103, and a mirror 105 is provided at a substantially center surrounded by the planar coil 104. The silicon substrate 101 is mounted on a frame-shaped insulating substrate 106. Place. The permanent magnet 107 is arranged so that the N pole and the S pole face each other on the opposite side surface of the silicon substrate 101. Reference numeral 108 in the figure
Are electrode terminals electrically connected to the planar coil 104.

This semiconductor galvanomirror has an electrode terminal 1
When an alternating current flows from 08 to the planar coil 104, an electromagnetic force acts on both ends of the movable plate 103 in accordance with Fleming's left-hand rule, and the movable plate 103 periodically swings around the torsion bar 102 in the direction of the arrow in the figure. Move. The frequency of the alternating current is set to the resonance frequency of the galvanometer mirror (for example, 1.5 k
Hz), the swing angle of the movable plate 103 can be increased with a small input.

If the above-described semiconductor galvanometer mirror is used as the optical scanning unit 12 and the optical system is designed so that the laser beam from the semiconductor laser 11 is irradiated on the mirror 105, the swinging operation of the movable plate 103 causes The laser beam is scanned at a required deflection angle.

The driving circuit for driving the resonance mirror of the optical scanning unit 12 includes a scanning frequency clock signal from the scanning frequency generation unit 14, an amplitude instruction signal from the automatic amplitude adjustment unit 17, and a signal from the sensor control unit 70. An optical scanning instruction signal is provided, and a drive signal for the resonant mirror is generated according to these signals.

The scanning frequency generating unit 14 is provided, for example, in FIG.
As shown in (A), it is composed of a counter 14A, a comparator 14B and a level inversion circuit 14C. In the scanning frequency generator 14, as shown in FIG. 4B, the counter 14A counts up in synchronization with the clock signal CLK output from the crystal oscillator OS, and the count value C
When 0 reaches a predetermined set value E0, a half cycle pulse signal is output from the comparator 14B. This half-period pulse signal is
The count value C0 is sent to the counter 14A to be reset, and is also input as a clock signal to the level inversion circuit 14C configured using a flip-flop. In the level inverting circuit 14C, the output level is alternately inverted to high or low in synchronization with the half-period pulse signal, and a scanning frequency clock signal close to the resonance frequency of the mirror of the optical scanning unit 12 is generated. The scanning cycle of the scanning frequency clock signal is 2 × E0 × T _CLK , and the scanning frequency is 1 / ｛2
× E0 × (1 / f _CLK )}.

The automatic amplitude adjusting section 17 is an amplitude of the laser beam scanned by the optical scanning section 12 (scanning range of the laser beam).
Is to generate an amplitude instruction signal for controlling so as to be constant at a required value. The circuit configuration of the automatic amplitude adjuster 17 is, for example, as disclosed in Japanese Patent Application No. 11-110
It is preferable to apply the technology proposed in -348856.

FIG. 5 is a block diagram showing an example of a circuit configuration of the automatic amplitude adjusting section 17 to which the above-mentioned prior application is applied. The automatic amplitude adjustment unit 17 illustrated in FIG. 5 is roughly divided into a small amplitude detection unit 210, a deviation detection unit 220, and an amplitude compensation unit 230. The small-amplitude detection unit 210 includes a first counter 211, a first comparator 212, and an OR circuit 213.

The first counter 211 has a scanning origin detecting unit 1
6 is enabled (a state in which count-up is permitted) in response to the signal from 6, the count is increased by the clock signal CLK from the crystal oscillator OS, and the count value C 1 is output to the first comparator 212.

The first comparator 212 has a first counter 211
Is compared with a preset set value E1, and when the count value C1 reaches the set value E1 (C1
= E1), the high-level output signal is sent to the OR circuit 213 and the amplitude compensator 230. The setting value E1 will be described later. The OR circuit 213 outputs the output signal of the first comparator 212 and the inverter 201 from the scanning origin detection unit 16.
And outputs a signal for resetting the count value C1 of the first counter 211 to 0 by performing a logical sum operation on the signal transmitted through Upon receiving the output signal from the OR circuit 213, the first counter 211 is reset.

The deviation detecting section 220 has, for example, a second counter 221, a second comparator 222, and a delay pulse generating circuit 223. The second counter 221 is enabled according to a signal sent from the scanning origin detecting unit 16 via the inverter 201, counts up by the clock signal CLK from the crystal oscillator OS, and compares the count value C2 with the second comparator. 222. Second comparator 2
22 compares the magnitude relationship between the count value C2 of the second counter 221 and a preset set value E2, and sends an output signal according to the comparison result to the amplitude compensator 230. In addition,
The setting value E2 and the output signal of the second comparator 222 will be described later.

The delay pulse generation circuit 223 synchronizes with the clock signal CLK from the crystal oscillator OS, and
It generates a delayed pulse signal DP2 that rises two counts after the fall of the output signal from 01 and outputs the delayed pulse signal DP2 to the second counter 221. Upon receiving this delay pulse signal DP2, the count value C2 of the second counter 221 is reset.

The amplitude compensator 230 includes, for example, a third counter 231, an OR circuit 232, and AND circuits 233 and 23.
4, 236, 237 and a delay pulse generation circuit 235.

The third counter 231 has an AND circuit 236
Is counted up by the output signal from
The countdown is performed by the output signal from the D circuit 237, and an amplitude instruction signal indicating a drive current set value determined according to the count value is sent to the optical scanning unit 12. The AND circuit 236 performs an AND operation on the output signal from the OR circuit 232 and the adjustment / detection mode signal from the sensor control unit 70, and outputs a signal that causes the third counter 231 to count up. The OR circuit 232 performs a logical OR operation on the output signal of the first comparator 212 of the small amplitude detector 210 and the output signal of the AND circuit 233, and outputs the result of the logical sum operation to the AND circuit 236.
Send to The AND circuit 233 is connected to the second
The comparator 222 logically combines the high-level output signal output when the count value C2 has not reached the set value E2 (C2 <E2) and the delay pulse signal DP3 output from the delay pulse generation circuit 235. The product operation is performed, and the result is transmitted to the OR circuit 232.

The AND circuit 237 performs a logical product operation of the output signal from the AND circuit 234 and the adjustment / detection mode signal, and outputs a signal for causing the third counter 231 to count down. The AND circuit 234 outputs a high-level output signal output from the second comparator 222 of the deviation detection unit 220 when the count value C2 has reached the set value E2 (C2> E2), and a delay pulse generation circuit. The logical AND operation is performed on the delayed pulse signal DP3 output from the 235 and the result is output to the AND circuit 237.

The delay pulse generation circuit 235 synchronizes with the clock signal CLK from the crystal oscillator OS and
A delay pulse signal DP3 which rises one clock delay from the fall of the output signal from 01 is generated, and the delay pulse signal DP3 is output to the AND circuits 233 and 234, respectively.

The amplitude of the laser beam scanned by the optical scanning unit 12 is controlled to a required constant value in accordance with the amplitude instruction signal output from the automatic amplitude adjusting unit 17 having the above configuration.

For example, as shown in FIG. 6, the scanning delay signal generating section 15 includes a low-pass filter constituted by using a resistor 15A and a capacitor 15B, and a comparator 15C for determining the level of a signal passing through the low-pass filter.
It is composed of In the scanning delay signal generating section 15,
The rising and falling edges of the scanning frequency clock signal generated by the scanning frequency generation unit 14 are dulled by a low-pass filter, and are divided into two values by a comparator 15C, thereby generating a delayed signal obtained by delaying the scanning frequency clock signal.

As shown in FIG. 7, for example, the scanning origin detecting section 16 includes inverters 16A and 16C and an AND circuit 16
B. In the scanning origin detecting section 16, the AND signal of the delay signal from the scanning delay signal generating section 15 and the signal obtained by inverting the output signal from the light receiving waveform processing section 30 by the inverter 16A are calculated by an AND circuit 16B. Is inverted by the inverter 16C. This inverter 1
The output signal of 6C is a signal indicating only the interruption on the scanning origin side among the interruptions of the reflected light generated at the upper end portion and the lower end portion of the reflection section 2, respectively. It is sent to the unit 50.

The light receiving waveform processing section 30 has, for example, a condenser lens 31 and a light receiving section 32. The condenser lens 31
The light retroreflected by the reflector 2 is focused on the light receiving surface of the light receiver 32. As the condenser lens 31, for example, a Fresnel lens or the like is preferably used. Although not shown, the light receiving section 32 includes a light receiving element, an amplification circuit, a detection circuit, and the like. The light receiving element receives the reflected light condensed by the condenser lens 31 and converts it into an electric signal, and the light receiving signal is amplified to a required level by an amplifier circuit. The detection circuit demodulates a modulated component of the received light based on an output signal from the amplification circuit. Then, based on the detected modulated component, it is determined whether or not the received reflected light is the reflected return light of the laser light sent from the optical scanning unit 12. If it is determined that the reflected light is the reflected return light, the received light waveform is changed. The output signal is output to the scanning origin detection unit 16 and the object position detection unit 50.

The object position detecting section 50 includes, for example, a counter reset signal generating section 51, an address counter 52, an RO
M53, a detection signal processing unit 54 and a detection position temporary holding unit 55.

The counter reset signal generator 51 includes an OR circuit 51A and an inverter 5 as shown in FIG.
1B and an AND circuit 51C. In the counter reset signal generation unit 51, the OR / detection mode signal from the sensor control unit 70 and the reset enable signal from the ROM 53 are ORed by the OR circuit 51A. The AND signal of the output signal from the origin detection unit 16 and the signal inverted by the inverter 51B is calculated by the AND circuit 51C. The operation result of the AND circuit 51C is stored in an address counter 52.
Is sent to the address counter 52 as a counter reset signal for resetting the count value of the counter.

The address counter 52 generates an address for reading data from the ROM 53, and counts up in synchronization with a clock signal CLK from the crystal oscillator OS. This count-up operation is performed in both the adjustment mode and the detection mode, which will be described later, and the count value is reset according to the counter reset signal from the counter reset signal generation unit 51.

The ROM 53 includes a table indicating a relationship between an address (time) and an angle, which will be described later, a flag indicating a period during which an object is detected in one cycle of optical scanning, and reception of reflected light on the scanning origin side. A flag indicating a period for detecting the absence is set in advance. And this ROM 53 is
According to the address output from the address counter 52, a signal indicating the angle data is output to the detection position temporary holding unit 55, and the object detection enable signal is output to the detection signal processing unit 54.
And outputs a reset enable signal to the counter reset signal generation unit 51. Note that the object detection enable signal is a signal that is output when the scanning position (angle) of the laser beam is within an area where the object can be measured.

The detection signal processing section 54 comprises, for example, an AND circuit 54A as shown in FIG. In the detection signal processing unit 54, the object detection enable signal from the ROM 53 and the light reception waveform from the light reception unit 32 are converted into an AND circuit 54.
By performing a logical product operation at A, a change in the received light waveform due to the presence of an object in the measurement area is determined. AND circuit 54A
Is output to the detection position temporary holding unit 55 as an object detection signal.

The detection position temporary holding unit 55 is, for example, as shown in FIG.
Are composed of latch circuits 55A and 55B, an inverter 55C, and an averaging circuit 55D. In the detection position temporary holding unit 55, the angle data sequentially sent from the ROM 53 is input to each of the latch circuits 55A and 55B. The latch circuit 55A holds the angle data at the rising edge of the object detection signal from the detection signal processing unit 54, and the latch circuit 55A holds the angle data at the falling edge of the object detection signal. Then, by averaging the angle data held by the latch circuits 55A and 55B by the averaging circuit 55D, angle data corresponding to the detected center position of the object is generated and output to the sensor control unit 70.

The sensor control unit 70 generates a laser lighting instruction signal, an optical scanning instruction signal, and an adjustment / detection mode signal in response to a command from the control unit 3.
The angle data output from the detection position temporary holding unit 55 is sent to the control unit 3.

The reflector 2 is composed of, for example, a support 2A and a retroreflector 2B as a retroreflector (FIG. 2). The retroreflective plate 2B is a general member having a reflective surface in which most of the reflected light is due to retroreflection. In this case, the retroreflector 2B is attached to a predetermined position on the surface of the support 2A facing the sensor unit 1. . Note that retroreflection means reflection in which reflected light is selectively returned in a direction substantially along the optical path of incident light over a wide incident angle.

The control unit 3 generates a signal for controlling the operation of the sensor unit 1 in response to a control command input from the outside or the like, and displays information on the object position measured by the sensor unit 1 on the display unit 4. Generate a signal to be displayed. Here, the case where the display unit 4 is provided and the measurement result is visually displayed has been described, but the measurement result is not limited to the display but can be externally displayed by a known output method.

Next, the operation of the object position measuring device having the above configuration will be described. First, the operation of the object position measuring device in the adjustment mode will be described. The adjustment mode is a mode for preparing a state in which the position of an object can be measured, for example, at startup.

In this apparatus, as shown in FIG.
The arrangement of the sensor unit 1 and the reflection unit 2 is such that the direction of the laser beam when the resonant mirror of the optical scanning unit 12 is stopped is positioned at the center of the retroreflective plate 2B in the scanning direction. It shall be set in advance. In this embodiment, the deflection angle (scanning angle) of the resonance type mirror is θ, and when the laser beam reaches one end (the lower end in FIG. 2) of the scanning range, the scanning origin (0 °) is set. the angle when it reaches the upper end) in FIG. 2, theta _max.

In the above setting, when there is no laser lighting instruction and light scanning instruction from the sensor control unit 70 and the semiconductor laser 11 is turned off and the resonant mirror is stopped, the light is reflected by the light receiving unit 32. Since no light is received, the output signal level of the light receiving section 32 becomes low as shown in the upper part of FIG.

When a signal for modulating the semiconductor laser 11 is output from the laser modulation control unit 13 in response to the laser lighting instruction from the sensor control unit 70, the resonance type mirror is stopped and the semiconductor laser 11 is stopped. Lights up,
The laser beam reflected by the retroreflector 2B is continuously received by the light receiving section 32, and the output signal level of the light receiving section 32 becomes a high level as shown in the middle part of FIG.

When the optical scanning section 12 receives an optical scanning instruction from the sensor control section 70, the scanning frequency generating section 14
The resonant mirror is driven according to the scanning frequency clock signal output from. Then, as the amplitude (scanning range) of the laser beam increases, the output signal level of the light receiving unit 32 changes to a low level once every half cycle of the resonance type mirror as shown in the lower part of FIG. The waveform is as follows. This is because the scanning of the laser beam deviates from both ends of the retroreflective plate and is not retroreflected, and the light receiving portion 32 stops receiving the reflected light.

It is known that the timing at which the light receiving waveform of the light receiving section 32 becomes low level varies according to the relationship between the frequency of the scanning frequency clock signal (drive frequency) and the resonance frequency of the mirror. This is because the mirror of the optical scanning unit 12 operates by resonance.

Specifically, as shown in FIGS. 12A to 12C, when the mirror is driven at a frequency higher than the resonance frequency, when the scanning frequency clock signal is at the low level,
The output of the light receiving section 32 becomes low level. On the other hand, when the mirror is driven at a frequency lower than the resonance frequency, when the scanning frequency clock signal is at a high level, the output of the light receiving unit 32 is at a low level.

In this apparatus, as will be described later, when the laser beam reaches the scanning origin, the measurement processing of the object position is reset. Therefore, the low-level output of the light receiving section 32 is output from the scanning origin side ( It is necessary to determine whether the signal is generated on the 0 ° side) or on the opposite side (θ _max side) based on the scanning frequency clock signal. However, when the relationship between the output level of the light receiving unit 32 and the scanning frequency clock signal fluctuates as described above, it becomes difficult to determine the scanning origin side.

Therefore, in this apparatus, a scanning delay signal generating section 15 as shown in FIG. 6 is provided to generate a scanning delay signal, and the scanning delay signal and the output level of the light receiving section 32 are used to generate a scanning delay signal. The scanning origin detection unit 16 shown in FIG.
The light receiving waveform on the scanning origin side is detected.

More specifically, when the scanning frequency clock signal passes through the low-pass filter of the scanning delay signal generator 15, a dull waveform signal as shown in FIG. The level is determined by the comparator 15C of the signal generation unit 15 to obtain the signal shown in FIG.
A scanning delay signal having a waveform as shown in FIG. It is desirable that the amount of delay in the scanning delay signal generating section 15 be about 1/4 cycle of the scanning frequency clock signal. The scanning origin detection unit 16 determines the scanning origin side when both the above-mentioned scanning delay signal and the signal obtained by inverting the light receiving waveform are at the high level, and the scanning origin side receiving light as shown in FIG. A signal indicating a waveform is output. FIG.
The signal waveform of (F) shows a waveform corresponding to the case where the drive frequency is higher than the resonance frequency.

When the scanning origin detection process is performed as described above, the control for keeping the amplitude of the laser beam at a predetermined constant value is performed using the scanning origin side received light waveform output from the scanning origin detecting unit 16. This is performed by the automatic amplitude adjusting unit 17.

FIG. 13 is a flowchart showing a specific operation of the automatic amplitude adjusting section 17. In FIG. 13, when the operation of the automatic amplitude adjustment unit 17 is started, first, in step 10 (indicated by S10 in the figure, the same applies hereinafter), the first
To the third counters 211, 221, 231 are reset, respectively. In step 20, it is determined whether the retroreflection light of the laser beam is received by the light receiving unit 32, that is, whether the light receiving waveform sent via the scanning origin detecting unit 16 is at a high level. . When it is determined that the reflected light is received, in step 30, the count value C1 of the first counter 211 is set to:
+1 according to the clock signal CLK from the crystal oscillator OS
The count is incremented, and the routine proceeds to step 40.

In step 40, the count value C 1 of the first counter 211 is set to the set value E in the first comparator 212.
It is determined whether or not 1 has been reached. This set value E1 is
For example, the count value is set to a value corresponding to about 1.5 times the resonance cycle of the mirror. First counter 211
When the count value C1 reaches the set value E1, it is determined that the laser light is turned on and the amplitude of the laser light is insufficient, and the process proceeds to step 50. On the other hand, if the count value C1 has not reached the set value E1, the process returns to step 20 and the above processing is repeated.

In step 50, the count value C1 of the first counter 211 is reset. At the same time, in step 60, a process of increasing the amplitude of the laser beam is performed. Specifically, a high-level output signal is output from the first comparator 212, and the output signal is output to the amplitude compensator 23.
0 is sent to the OR circuit 232. In the OR circuit 232,
In response to the input of the high-level signal from the first comparator 212, a high-level output signal is sent to the AND circuit 236. A high-level signal corresponding to the adjustment mode is input to the AND circuit 236, and a high-level output signal is sent to the third counter 231. Third counter 23
1 counts up upon receiving a high-level output signal from the AND circuit 236, thereby increasing the amplitude of the scanning light to 1
An instruction to increase the level is sent to the optical scanning unit 12. As a result, the magnitude of the driving current supplied to the resonant mirror of the optical scanning unit 12 increases by one level, and the driving state is adjusted so that the amplitude of the scanning light increases.

If it is determined in step 20 that no reflected light is received, the process proceeds to step 70, where the time when the light receiving waveform on the scanning origin side is at the low level is measured. Specifically, in step 70, the output signal from the inverter 201 goes high every mirror resonance cycle, so that the count value C of the first counter 211
It is reset before 1 reaches the set value E1 (set to about 1.5 times the resonance period). At the same time, in step 80, the second counter 221 receiving the high-level output signal from the inverter 201 switches to the enable state and counts up by +1 according to the clock signal CLK from the crystal oscillator OS. Then, in step 90, it is determined whether or not the retroreflected light of the laser light is received by the light receiving unit 32. If it is determined that the reflected light is received, the process proceeds to step 100. On the other hand, if it is determined that no reflected light is received,
Returning to step 80, the above operation is repeated. When the semiconductor laser 11 is not turned on, it is determined that there is no light reception in the above step 90.
Until 1 lights up, the operations of steps 80 and 90 are repeated.

Here, the above steps 70 to 90
The principle of the time measurement performed in the above will be briefly described. FIG. 14 shows an output signal (showing a light receiving waveform on the scanning origin side) from the scanning origin detection unit 16 and a delay pulse signal DP.
2 is a diagram showing an example of a signal waveform of DP3 together with a locus (upper stage) of a laser beam retroreflected by a reflection unit 2. FIG.

As shown in FIG. 14, when the laser beam to be scanned reaches outside the lower end of the retroreflective plate 2B (point [1]),
The light reception waveform changes from high level to low level. Then, while the laser light is scanned from [1] to [2] on the surface of the support 2A where the retroreflection plate 2B is not provided, the received light waveform is at a low level. The time during which the low level is maintained is n counts corresponding to the count value synchronized with the clock signal CLK (corresponding to the count value C2 of the second counter 21).
_Is n · T _CLK .

When the laser beam reaches the point [2] and the received light waveform changes to a high level, the rising edges thereof are detected by the delay pulse generation circuits 223 and 235, respectively.
In an actual circuit, the light receiving waveform from the scanning origin detecting unit 16 is inverted by the inverter 201 and is supplied to the delay pulse generating circuits 223 and 235.
The falling of the output signal from the delay pulse generation circuit 2
23, 235.

A delay pulse signal DP3 which rises one count delay (n + 1 count) from the rise of the received light waveform is generated by the delay pulse generation circuit 235, and a delay pulse signal DP3 which rises two count delays (n + 2 counts) is It is generated by the delay pulse generation circuit 223.

Next, at step 100, the second comparator 2
At 22, the count value C2 corresponding to the time when the light reception waveform on the scanning origin side is at the low level is compared with the set value E2. The set value E2 is set corresponding to the time when the light receiving waveform on the scanning origin side is at a low level when the amplitude of the scanning light reaches a predetermined required amplitude. Therefore, when the count value C2 is equal to the set value E2 (C2 = E2), it is determined that the required amplitude is obtained, and when the count value C2 is smaller than the set value E2 (C2 <E2), When the amplitude is determined to be insufficient and the count value C2 is larger than the set value E2 (C
In 2> E2), it is determined that the amplitude is too large.

If it is determined that the amplitude of the scanning light is insufficient (C2 <E2), the process proceeds to step 110, where the high-level output signal is sent from the second comparator 222 to the amplitude compensator 230.
Is sent to the AND circuit 233. On the other hand, if it is determined that the amplitude of the scanning light is too large (C2> E2),
Proceeding to step 120, the high level output signal is
The signal is sent from the comparison unit 222 to the AND circuit 234 of the amplitude compensation unit 3. The delay pulse signal DP3 from the delay pulse generation circuit 235 is input to each of the AND circuits 233 and 234, and when both the output signal from the second comparator 222 and the delay pulse signal DP3 become high level. ,
A high-level output signal is output from each of the AND circuits 233 and 234.

The delay pulse signal DP3 becomes high level after the light receiving waveform on the scanning origin side has changed from low level to high level as shown in FIG. During the counting operation, AN
A high-level signal is not output from the D circuits 233 and 234, and amplitude deviation compensation is performed after the determination of the time when the light receiving waveform on the scanning origin side is at the low level is completed.

When a high-level output signal is output from the AND circuit 233, the output signal is input to the OR circuit 232, and a high-level signal is output from the OR circuit 232. Further, the output signal from the OR circuit 232 is an AN to which a high-level signal indicating the adjustment mode is input.
The signal is sent to the D circuit 236, and a high-level signal is output from the AND circuit 236. Thereby, the third counter 23
1 is counted up, and the driving current supplied to the resonance type mirror of the optical scanning unit 12 is increased by one level, and the driving state is adjusted so that the scanning amplitude of the laser light is increased. Then, in step 130, the second counter 2
After the count value C2 of 21 is reset, the process proceeds to step 20 described above, and the same processing is repeated.

On the other hand, when a high-level signal is output from the AND circuit 234, the output signal is sent to the AND circuit 237 to which the high-level signal indicating the adjustment mode is input, and the high-level signal is output from the AND circuit 237. Is output. Thereby, the third counter 231 counts down, and the magnitude of the driving current supplied to the resonant mirror of the optical scanning unit 12 is reduced by one level, and the driving state is adjusted so that the amplitude of the laser light is reduced. Is done. Then, after the count value C2 of the second counter 221 is reset in step 130, the process proceeds to step 20 described above, and the same processing is repeated. If it is determined in step 100 that the count value C2 is equal to the set value E2, the process proceeds to step 130.

Steps 10 to 13 as described above
A series of processing of 0 is repeatedly executed by the automatic amplitude adjustment unit 17 while the adjustment mode is selected by the adjustment / detection mode signal. As a result, the laser beam is stably scanned at a required amplitude.

Next, the operation of the object position measuring apparatus in the detection mode will be described. The detection mode is a mode in which the position of the object is actually measured. In the present apparatus, when the adjustment / detection mode signal from the sensor control unit 70 indicates the detection mode, the object position detection unit 50 based on the output signal from the scanning origin detection unit 16 and the light reception waveform from the light reception unit 32.
, An object position detection process is executed. In the object position detection unit 50, first, an address counter 52
Is generated by the counter reset signal generation unit 51.

FIG. 15 shows the counter reset signal generator 5.
FIG. 3 is a timing chart illustrating the operation of FIG. In the counter reset signal generation section 51 having the configuration as shown in FIG. 8 described above, the sensor control section 70 as shown in FIG.
Is sent to the OR circuit 51A, and a reset enable signal from the ROM 53 as shown in FIG. 15B is input to the OR circuit 51A. The reset enable signal from the ROM 53 is a signal that goes high when an address corresponding to a reset enable flag preset in the ROM 53 is sent from the address counter 52 to the ROM 53.

When the adjustment / detection mode signal indicates the high-level adjustment mode, the output signal of the OR circuit 51A is at the high level regardless of the reset enable signal from the ROM 53, as shown in FIG. Fixed to As a result, corresponding to the received light waveform inverted by the inverter 51B as shown in FIG.
The counter reset signal shown in FIG.
Output from In the adjustment mode, only the interruption of the light reception outside both ends of the retroreflective plate 2B has no factor for setting the light reception waveform to the low level, so that the counter reset signal is generated based on the light reception waveform on the scanning origin side. On the other hand, when the adjustment / detection mode signal indicates a low-level detection mode, the reset enable signal from the ROM 53 and the light-receiving waveform on the scanning origin side inverted by the inverter 51B both become high-level. Only a high-level counter reset signal is generated. In other words, in the detection mode, the light reception is interrupted when an object is detected in addition to the light interruption on the scanning origin side. However, the address counter 52 is not reset by such light interruption when the object is detected.

In the address counter 52, the crystal oscillator O
The value of the address transmitted to the ROM 53 is counted up in accordance with the clock signal CLK from S, and the count value is reset by the above-mentioned counter reset signal when the laser beam passes the scanning origin.

FIG. 16 is a timing chart for explaining the operation of the object position detector 50 in the detection mode. In the detection mode, a signal indicating a light receiving waveform as shown in FIG. 16A is sent from the light receiving unit 32 to the object position detecting unit 50, and a low level light receiving waveform corresponding to the scanning origin side changes to a high level. The address counter 52 is reset as shown in FIG. RO receiving the address output from address counter 52
In M53, a reset enable signal as shown in FIG. 16C is output to the counter reset signal generator 51, and an object detection enable signal as shown in FIG. 16D is output as the detection signal. The object detection enable signal is a signal that goes high when an address corresponding to an object detection enable flag preset in the ROM 53 is sent from the address counter 52 to the ROM 53. Specifically, the timing at which the scanning light can be surely reflected by the retroreflector 2B, that is, from immediately after the rising of the interruption of light reception on the scanning origin side to immediately before the falling of the interruption of light reception on the opposite side to the scanning origin, And immediately after the rising of the interruption of light reception on the opposite side of the scanning origin,
It is set so that a high-level object detection enable signal is output when an address corresponding to immediately before the falling of the interruption of light reception on the scanning origin side is received.

In the ROM 53, the angle data corresponding to the address from the address counter 52 is sequentially output to the detection position temporary holding unit 55. This angle data is
Based on the time when the laser beam scanned with the required amplitude passes through the scanning origin, the data corresponding to the scanning angle is RO.
This is preset in M53.

Here, the relationship between the address output from the address counter and the scanning angle of the laser beam will be described. Generally, the deflection angle (scan angle) θ of the resonance type mirror
Changes with time in a sin waveform as shown in FIG. Therefore, the scanning angle θ at time t when the resonance cycle of the mirror is T is expressed by the following equation (1).

[0089]

(Equation 1)

Here, n is the address value (n = 0, 1, 2,..., M) of the address counter 52, and T _CLK is the period of the clock signal CLK output from the crystal oscillator OS. The maximum scanning angle θ _max is defined as follows: X is the distance from the reflection surface of the resonance mirror to the reflection unit 2, and Y is the maximum amplitude of the scanning light on the reflection unit 2, and θ _max = tan ^−1.
It is a constant determined by (Y / X).

In the detection signal processing section 54 receiving the object detection enable signal from the ROM 53, the AND circuit 54A calculates the logical product of the object detection enable signal and the signal indicating the light reception waveform output from the light reception section 32. As a result, an object detection signal having a high level is generated as shown in FIG. 16E in response to the interruption of light reception by only the object, and the object detection signal is output to the detection position temporary holding unit 55.

In the detection position temporary holding section 55, the ROM 53
From the detection signal processing unit 5
The latch circuits 55A and 55B respectively latch (hold the state) based on the high-level object detection signal from the control circuit 4. Here, the latch circuit 55A and the latch circuit 55
At A, the angle data at the rise and fall of the object detection signal is latched, respectively. Then, the average value of the latched angle data is calculated by the averaging circuit 55, and the angle corresponding to the center position of the object is obtained.

The position information of the object calculated by the detection position temporary holding unit 55 is sent to the control unit 3 via the sensor control unit 70. In control unit 3,
A signal for controlling the display unit 4 is generated in accordance with information from the sensor control unit 70. Thereby, the position information of the object measured by the sensor unit 1 is displayed on the display unit 4.

As described above, according to the object position measuring device of the first embodiment, the scanning origin is detected while controlling the amplitude of the scanning light to be constant using one light emitter and one light receiver. Since the object is measured based on the passage timing of the scanning origin, the position (direction) of the object in the scanning area can be measured with high speed and high accuracy by using a simpler configuration than the conventional device. Becomes possible.

Next, a second embodiment of the present invention will be described. In the first embodiment described above, since the position of the object is measured using one sensor unit 1, the direction of the object present in the measurement area can be detected at high speed and with high accuracy. Was. In the second embodiment, a case will be described in which the position (horizontal / vertical coordinates) of an object in a measurement area can be specified by combining a plurality of sensor units.

FIG. 18 is a block diagram showing a functional configuration of the object position measuring device according to the second embodiment. Also,
FIG. 19 is a perspective view showing the appearance of the apparatus shown in FIG. 18 and 19, the present object position measuring device includes, for example, four sensor units 1A, 1B, 1C, and 1D.
A reflection unit 2a for reflecting each scanning light transmitted from the sensor units 1A and 1B;
The control unit 300 includes a reflecting unit 2b that reflects each scanning light transmitted from C and 1D, and a control unit 300 that performs operation control of each of the sensor units 1A to 1D and arithmetic processing of an object position. Here, the reflection parts 2a, 2b
Correspond to the first and second light reflecting means, and the control unit 300 has a function corresponding to the calculating means.

Each of the sensor units 1A to 1D has the same configuration as the sensor unit 1 used in the first embodiment, and each of the sensor control units 70 is connected to the control unit 300.

Each of the reflectors 2a and 2b has the same configuration as the reflector 2 used in the first embodiment. Here, as shown in FIG. 19, the sensor units 1A and 1B are attached to the support of the reflector 2a, and the sensor units 1C and 1D are attached to the support of the reflector 2b. In addition, each sensor unit 1A-1D in this invention
Is not limited to the above.

The control unit 300 includes, for example,
CPU 301, I / O interface 302, and C
ROM 303 and RAM 304 connected to PU 301
And consisting of Each of the sensor units 1A to 1D is connected to the I / O interface 302,
Data is exchanged with the communication device 301 and the first
The display unit 4 similar to that of the embodiment is also connected,
Display control of the measurement result is performed.

In the object position measuring device having the above-described configuration, in accordance with each signal of the laser lighting instruction, the optical scanning instruction, and the adjustment / detection mode output from the control unit 300, the same as in the first embodiment described above. Is performed in each of the sensor units 1A to 1D. The measurement results of the sensor units 1A to 1D are sent to the CPU 3 via the I / O interface 302.
01 is sent.

In the CPU 301, each of the sensor units 1A to 1A is operated in accordance with an arithmetic program stored in the ROM 303.
Using the measurement result from D, the position of the object in the measurement area is obtained. Here, as shown in FIG.
A rectangular measurement area formed by each scanning range of the four sensor units 1A to 1D has four small areas AB and C.
D, AC, and BD are classified, and the position of the object is calculated using the measurement results from two sensor units corresponding to each small area.

Specifically, when the object is present in the small area AB as shown in FIG. 20, the measurement result of the sensor unit 1A (scan angle θ _A corresponding to the position of the object) and the measurement result of the sensor unit 1A ( Using the angle θ _B ), the coordinates (x, y) of the object within the measurement area are calculated. Note that FIG.
As indicated by 0, here, the distance from each sensor unit to the opposing retroreflective plate is X, and the length of the retroreflective plate in the scanning direction of the laser light is Y.

The coordinates (x, x) of the object existing in the small area AB
The relationship between y) and the angles θ _A and θ _B can be expressed by the following equations (2) and (3). y = x · tan θ _B (2) Y−y = x · tan θ _A (3) By substituting the equation (2) into the equation (3), the x coordinate of the object is expressed by the following equation (4). expressed.

Y−x · tan θ _B = x · tan θ _A Y = x · (tan θ _A + tan θ _B ) x = Y / (tan θ _A + tan θ _B ) (4) By rearranging by substituting the relationship, the y coordinate of the object is expressed by the following equation (5).

Y = Y · tan θ _B / (tan θ _A + tan θ _B ) (5) Therefore, the object is detected by the sensor units 1A and 1B, and the angles θ _A and θ _B indicating the directions are sent to the CPU 301. In this case, the coordinates of the object are calculated using the relationship of the above equations (4) and (5). Then, the calculated coordinate information of the object is displayed on the display unit 4 connected to the CPU 301 via the I / O interface 302, for example.

Further, as shown in FIG.
D, the coordinates (x, y) of the object in the measurement area are obtained using the measurement result (angle θ _C ) of the sensor unit 1C and the measurement result (angle θ _D ) of the sensor unit 1D.
Is calculated. The coordinates (x, y) of the object and the angles θ _C , θ _D
Can be expressed by the following equations (6) and (7).

Y = (X−x) · tan θ _D (6) Y−y = (X−x) · tan θ _C (7) Based on the equations (6) and (7), the small area When the x coordinate and the y coordinate of the object are obtained in the same manner as in the case of AB, the following equations (8) and (9) are obtained.

X = XY / (tan θ _C + tan θ _D ) (8) y = Y · tan θ _D / (tan θ _C + tan θ _D ) (9) Further, as shown in FIG. If there is, the measurement result of the sensor unit 1A (angle θ _A ) and the measurement result of the sensor unit 1C (angle θ _C )
Is used to calculate the coordinates (x, y) of the object in the measurement area. The relationship between the coordinates (x, y) of the object and the angles θ _A , θ _C can be expressed by the following equations (10) and (11).

Y−y = X · tan θ _A (10) Yy = (X−x) · tan θ _C (11) Based on the equations (10) and (11), the small area AB
When the x coordinate and the y coordinate of the object are obtained in the same manner as in the case of, the following expressions (12) and (13) are obtained.

X = X · tan θ _C / (tan θ _A + tan θ _C ) (12) y = Y−X · tan θ _A · tan θ _C / (tan θ _A + tan θ _C ) (13) In addition, as shown in FIG. When the object exists in the small area BD, the measurement result of the sensor unit 1B (angle θ _B ) and the measurement result of the sensor unit 1D (angle θ _D )
Is used to calculate the coordinates (x, y) of the object in the measurement area. The relationship between the coordinates (x, y) of the object and the angles θ _B and θ _D can be expressed by the following equations (14) and (15).

Y = X · tan θ _B (14) y = (X−x) · tan θ _D (15) Based on the equations (14) and (15), the above-described small area AB
When the x and y coordinates of the object are obtained in the same manner as in the case of, the following expressions (16) and (17) are obtained.

X = X · tan θ _D / (tan θ _B + tan θ _D ) (16) y = X · tan θ _B · tan θ _D / (tan θ _B + tan θ _D ) (17) As described above, the four sensor units are provided. When the direction of the object is detected in any two of 1A to 1D, the coordinates (x, y) of the object are calculated using the above calculation formula for the corresponding small area.

When an object is located at the boundary of a small area, its direction is measured by two or more sensor units. In such a case, for example, priorities may be set for four small areas, and the calculation processing may be performed for an area with a high priority. Further, for example, the coordinates may be calculated for each small area, and the results may be averaged.

When the position of an object is calculated using the above-described calculation formula, the RO of each of the sensor units 1A to 1D is calculated.
It is desirable to set a tangent value (tan θ) of the scanning angle θ corresponding to the address as the angle data previously stored in the M53. By doing so, the CPU 30
The coordinate calculation executed in step 1 is performed by each of the sensor units 1A to 1A.
Since only the addition, subtraction, multiplication, and division of tan θ sent from D are performed, there is an advantage that high-speed arithmetic processing can be performed.

As described above, according to the second embodiment, for example, a rectangular measurement area is formed using the four sensor units 1A to 1D, and the scanning indicating the direction of the object detected by at least two sensor units is performed. By calculating the angle θ, the horizontal and vertical coordinates in the measurement area of the object can be measured at high speed and with high accuracy.

In the above-described second embodiment, a configuration using four sensor units has been described. However, the present invention calculates the coordinates of an object in a measurement area by combining two or more sensor units. Is possible.
For example, in the case of using two sensor units, a portion where the scanning range of each sensor unit overlaps becomes a measurement region, and the coordinates of an object located in the measurement region can be calculated.

When a plurality of sensor units are used in combination, care must be taken so that no mutual interference occurs between the sensor units. In particular,
For example, a situation as shown in FIG. 24 is assumed. That is, the retroreflective plate 2B basically has the property of reflecting most of the laser light emitted from the sensor unit in the incident direction, but some of the laser light is reflected on the glossy surface of the retroreflective plate. The light is reflected like a normal mirror, and there is a possibility that the laser light emitted from the sensor unit 1A is directed to the sensor unit 1B as indicated by the solid line arrow in the side view of FIG. Therefore, if the laser light from the sensor unit 1A is received by the sensor unit 1B at the moment when the sensor unit 1B is capturing the object, the object may not be actually detected.

In order to cope with the mutual interference between the sensor units as described above, for example, the modulation frequency of the laser beam and the detection frequency corresponding thereto may be different for each sensor unit. The laser light emitted from each sensor unit is modulated mainly to distinguish it from disturbance light, but by changing the modulation frequency for each sensor unit, mutual interference between sensor units Can be avoided.

Further, for example, the normal direction of the reflection surface of the retroreflection plate 2B is arranged at an angle to the scanning plane formed by the scanning light, that is, as shown in FIG. On the other hand, a method of arranging the retroreflective plate 2B by inclining outward (inclination angle α) is also effective. By doing so, even if the laser light emitted from one sensor unit is specularly reflected by the retroreflective plate 2B, the reflected light is deflected by an angle 2α as shown in the top view of FIG. Since the light propagates, the light is not received by the other sensor unit, and mutual interference between the sensor units can be avoided.

Next, a third embodiment of the present invention will be described. In the second embodiment described above, the horizontal and vertical coordinates of the object in the measurement area are measured using four sensor units. In the third embodiment, an object position measuring device capable of measuring the position, moving direction, and average speed of a moving object will be described.

FIG. 26 is a perspective view showing the main configuration of an object position measuring apparatus according to the third embodiment. As shown in FIG. 26, the present object position measuring device substantially separates first and second measurement areas F1 and F2 formed in the same manner as in the above-described second embodiment by a predetermined distance L. It has a configuration arranged in parallel. However, FIG.
1 and F2, and only the reflecting portions 2a, 2b, 2c and 2d located at both ends of the respective measurement areas F1 and F2.
The display of a total of eight sensor units located at the four corners of each of the measurement areas F1 and F2, and the control units that perform the operation control of each sensor unit and the arithmetic processing of the position of the object and the like are omitted.

In the object position measuring apparatus having the above-described configuration, assuming that the object moves from the measurement area F1 to the measurement area F2 as shown by, for example, a thick arrow in FIG. Operation is performed.

First, as the object passes through the measurement area F1, as in the case of the above-described second embodiment,
The horizontal and vertical coordinates (x
₁ , y ₁ ) are calculated and stored by the control unit. In the present apparatus, the time when the object passes through the measurement area F1 is also measured and stored in the control unit.
Further, when the object passes through the measurement area F2, the horizontal and vertical coordinates (x ₂ , y ₂ ) of the object in the measurement area F2 are calculated by the control unit in the same manner as in the above-described second embodiment. are stored together with the passage time t _2.

In the control unit, the passing coordinates (x ₁ ,
Using y ₁ ), (x ₂ , y ₂ ) and the time t (= t ₂ −t ₁ ) required for the movement between the measurement areas F1 and F2, the moving direction vector and the average velocity of the object are obtained. Specifically, the moving direction vector of the object is (x ₂ −x ₁ , y ₂ −y ₁ ,
L). The average velocity v of the object is given by
Is calculated by the equation (18) shown below.

[0125]

(Equation 2)

As described above, according to the third embodiment, the two measurement areas F1 and F2 formed using four sensor units and the like are arranged at a predetermined distance from each other, and the respective measurement areas F1 and F2 are arranged. By measuring and processing the passing position and passing time of the object in, the position, direction, and average speed of the moving object can be measured with high accuracy using a simple configuration.

Such a device is suitable for use in estimating, for example, the moving direction, speed, and flight distance of a ball used in various ball games. Further, for example, the present invention can be applied to an application in which it is installed on a runway or the like of an airfield to estimate a takeoff and landing angle and a speed of an aircraft. However, the application of the object position measuring device according to the present invention is not limited to the above.

In the first to third embodiments described above, the configuration is described in which the retroreflective plate is arranged at the center portion excluding the both ends with respect to the scanning range of the scanning light. It is also possible to arrange the retroreflectors only at both ends of the scanning range and to prevent the scanning light from being retroreflected at the center. In this case, it is possible to perform the same handling as in the above-described embodiments by inverting the relationship between the high level and the low level of the light receiving waveform in the light receiving unit. However, the detection of the object in the measurement area is determined by receiving the scanning light reflected by the object by the light receiving unit, and therefore, it is necessary to use a light receiving unit having high light receiving sensitivity.

In the first to third embodiments described above, the laser beam is scanned on a straight line, but the present invention is not limited to this. For example, a light emitting diode or the like may be used as a light source, and an application in which a movable mirror is two-dimensionally driven to extend a scanning range is also possible.

[0130]

As described above, the object position measuring apparatus of the present invention scans light from a light source using a movable mirror and sends it to a measurement area, and retroreflects the scanning light with light reflecting means. The light receiving means detects the position of the object in the measurement area based on the change in the light receiving state. And it becomes possible to measure with high precision.

Further, by forming a measurement region using a plurality of sensor units and using the detection results of the objects in at least two sensor units in combination, the coordinates of the object in the measurement region can be calculated. This makes it possible to more accurately measure the position of the object with a simple configuration.

Further, the first measurement area and the second measurement area are arranged substantially in parallel at a predetermined interval, the position of the moving object is detected along with the passing time in each measurement area, and the detection results are combined. By using this, it is also possible to calculate the moving direction and speed of the object.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment according to the present invention.

FIG. 2 is a perspective view showing an appearance of the first embodiment.

FIG. 3 is an exploded view showing a configuration example of a semiconductor galvanometer mirror used in the first embodiment.

FIG. 4 is a diagram showing a scanning frequency generation unit according to the first embodiment, in which (A) is a block diagram showing a configuration example and (B).
FIG. 4 is a diagram showing waveforms of respective parts.

FIG. 5 is a block diagram illustrating a configuration example of an automatic amplitude adjusting unit according to the first embodiment;

FIG. 6 is a circuit diagram showing a configuration example of a scanning delay signal generator of the first embodiment;

FIG. 7 is a circuit diagram showing a configuration example of a scanning origin detecting unit according to the first embodiment;

FIG. 8 is a circuit diagram illustrating a configuration example of a counter reset signal generation unit according to the first embodiment;

FIG. 9 is a circuit diagram illustrating a configuration example of a detection signal processing unit according to the first embodiment;

FIG. 10 is a circuit diagram illustrating a configuration example of a detection position temporary holding unit according to the first embodiment;

FIG. 11 is a diagram for explaining the output of the light receiving unit when the device is activated in the first embodiment.

FIG. 12 is a diagram illustrating an operation of detecting a scanning origin in the first embodiment.

FIG. 13 is a flowchart showing a specific operation of the automatic amplitude adjustment unit in the first embodiment.

FIG. 14 is a diagram showing an example of a light receiving waveform on the scanning origin side and a waveform example of a delay pulse signal together with a locus of retroreflected light in the first embodiment.

FIG. 15 is a diagram illustrating an operation of a counter reset signal generation unit in the first embodiment.

FIG. 16 is a diagram illustrating an operation of the object position detection unit in the detection mode in the first embodiment.

FIG. 17 is a diagram showing a time change with respect to a deflection angle of a general resonance type mirror.

FIG. 18 is a block diagram showing a functional configuration of a second embodiment according to the present invention.

FIG. 19 is a perspective view showing the appearance of the second embodiment.

FIG. 20 is a view showing a case where an object is a small area A in the second embodiment;
FIG. 9 is a diagram for explaining a case where the data exists in B.

FIG. 21 is a view showing a case where an object is a small area C in the second embodiment;
FIG. 9 is a diagram for explaining a case where the data exists in D.

FIG. 22 is a view showing a case where an object is a small area A in the second embodiment;
FIG. 9 is a diagram for explaining a case where the data exists in C.

FIG. 23 shows a case where the object is a small area B in the second embodiment.
FIG. 9 is a diagram for explaining a case where the data exists in D.

FIG. 24 is a diagram illustrating mutual interference between two sensor units.

25 is a diagram illustrating a configuration example capable of avoiding the mutual interference in FIG. 24; It is a perspective view which shows a principal part structure.

FIG. 26 is a perspective view showing a configuration of a main part of a third embodiment according to the present invention.

[Explanation of symbols]

 1, 1A to 1D: Sensor unit 2, 2a to 2d: Reflecting unit 2A: Support column 2B: Retroreflector 3,300: Control unit 4: Display unit 10: Laser beam stable scanning unit 11: Semiconductor laser 12: Optical scanning unit DESCRIPTION OF SYMBOLS 13 ... Laser modulation control part 14 ... Scan frequency generation part 15 ... Scan delay signal generation part 16 ... Scan origin detection part 17 ... Amplitude automatic adjustment part 30 ... Light receiving waveform processing part 31 ... Condenser lens 32 ... Light receiving part 50 ... Object position Detecting section 51: Counter reset signal generating section 52: Address counters 53, 303 ROM 54: Detection signal processing section 55: Temporary detection position holding section 70: Sensor control section 301: CPU 302: I / O interface 304: RAM

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2F065 AA01 DD02 DD19 FF02 FF41 GG06 GG23 HH04 HH15 JJ01 JJ05 JJ15 LL13 LL16 LL62 MM16 NN08 QQ11 QQ23 QQ25 QQ51 5J084 AA04 AA10 AB17 AD06 BA04 BA05 BA05 BA04 CA52 CA53 DA01 DA02 DA08 EA04 EA31 FA03

Claims (14)

[Claims] An optical scanning means for irradiating a movable mirror with light emitted from a light source to generate scanning light for scanning a predetermined measurement area; and an optical scanning means arranged to face the optical scanning means; Light reflecting means capable of retroreflecting the scanning light sent from the scanning means; light receiving means arranged near the light scanning means for receiving light retroreflected by the light reflecting means; Object detecting means for detecting a position of an object present in the measurement area based on a scanning direction of light in a scanning means and a change in a light receiving state in the light receiving means. Object position measurement device. 2. The object position measuring apparatus according to claim 1, wherein said optical scanning means uses a resonance type mirror driven by utilizing an electromagnetic force as said movable mirror. 3. The resonance type mirror is provided with a mirror and a coil on a surface of a movable plate pivotally supported via a torsion bar, and a magnetic field is applied to a coil portion parallel to the axial direction of the torsion bar. Magnetic field generating means for acting
The object position measuring device according to claim 2, further comprising a structure for supplying an alternating current for driving the movable plate to the coil to swing the movable plate. 4. The light scanning means scans the light from the light source in a straight line, and the light reflection means scans both ends of the scanning range with respect to the scanning range of the light sent from the light scanning means. The object position measuring device according to any one of claims 1 to 3, further comprising a retroreflective portion disposed at a central portion excluding the portion. 5. The light scanning means scans the light from the light source on a straight line, and the light reflection means scans both ends of the scanning range with respect to the scanning range of the light sent from the light scanning means. A retroreflective section disposed on each of the sections.
3. The object position measuring device according to any one of 3. 6. The optical scanning means according to claim 1, wherein said light scanning means periodically changes the light receiving state of said light receiving means in response to the scanning of the light from said light source to one end of a scanning range. A scanning origin detection unit that identifies an origin of optical scanning; the object detection unit includes: an elapsed time after the scanning light passes through the scanning origin specified by the scanning origin detection unit; and a light receiving state of the light receiving unit. The object position measuring apparatus according to claim 4, wherein a scanning angle corresponding to a position of an object existing in the measurement area is detected based on the change of the object position. 7. An object position measuring apparatus according to claim 6, wherein said object detecting means sets angle data relating to a scanning angle corresponding to said elapsed time in advance. 8. An amplitude automatic adjustment for monitoring a light scanning range based on a light receiving state of the light receiving means and controlling a driving state of the resonance type mirror so that the scanning range becomes constant. The object position measuring device according to claim 1, further comprising a unit. 9. A plurality of sensor units each including the light scanning unit, the light receiving unit, and the object detection unit, and the light reflection unit is configured such that each of the sensor units includes a scanning range of scanning light overlapping each other. An arithmetic unit configured to calculate a coordinate of an object in the measurement area based on a position of the object detected by at least two object detection units of the plurality of sensor units. The object position measuring apparatus according to claim 1, wherein the object position is measured. 10. A light-reflecting device comprising: a first light-reflecting means facing a reflecting surface; and two or more sensor units arranged to face the first light-reflecting means; 10. The object position measuring device according to claim 9, wherein two or more sensor units are arranged to face each other, and a planar measurement area is formed between the first and second light reflecting means. . 11. A sensor comprising a first and a second light reflecting means and a third and a fourth light reflecting means opposed to a reflecting surface, wherein two or more of said sensors are opposed to said first light reflecting means. A unit is arranged and faces the second light reflecting means.
One or more of the sensor units are arranged to form a planar first measurement area between the first and second light reflecting means, and two or more of the sensors are arranged to face the third light reflecting means. A unit is arranged and faces the fourth light reflecting means.
Two or more sensor units are arranged to form a planar second measurement area between the third and fourth light reflecting means, and the first measurement area and the second measurement area are separated by a predetermined distance. The position of the object and the passage time of the object calculated for the first measurement area, and the position of the object and the passage time of the object calculated for the second measurement area 10. The object position measuring device according to claim 9, wherein information on a moving state of the object is calculated based on the information. 12. Each of the sensor units transmits scanning light modulated at a different frequency from each other, and determines whether or not each of the sensor units is reflected light of the scanning light transmitted by itself based on the modulation frequency of the light received by the light receiving means. The object position measuring apparatus according to claim 9, further comprising: a unit for identifying the object position. 13. The light reflection means according to claim 9, wherein a normal direction of the reflection surface is arranged at an angle to a scanning plane formed by the scanning light. An object position measuring device according to any one of the above. 14. The object position according to claim 9, wherein a tangent value of the scanning angle is set in advance in each of the object detecting means as angle data in each of the sensor units. Measuring device.