JP2018169196A - Measurement device, printer, and electronic apparatus - Google Patents

Abstract

To provide a measurement device which can make a highly accurate measurement.SOLUTION: The measurement device includes: a first semiconductor laser emitting a first laser light; a second semiconductor laser emitting a second laser light; a first driving unit for operating the first semiconductor laser so that there alternately come periods when the wavelength of the first laser light continuously and monotonously increases and periods when the wavelength of the first laser light continuously and monotonously decreases; and a second driving unit for operating the second semiconductor laser so that the respective phases of the variations in the wavelengths of the second laser light and the first laser light will be reverse phases, the first and second semiconductor lasers being located on the same substrate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a measurement device, a printer, and an electronic device.

  2. Description of the Related Art As a measuring device that measures the distance to a measurement target and the speed of the measurement target using laser light in a non-contact manner, a device using a self-coupling effect is known. The self-coupling effect is a phenomenon in which the output of the light source increases or decreases due to the interference between the return light returned from the light source scattered by the laser light irradiated to the measurement target from the light source and the output light of the light source.

  For example, in Patent Document 1, as a light source, a first semiconductor laser that emits a first laser beam to a measurement target and a second laser beam that emits a second laser beam to the measurement target in parallel with the first laser beam are disclosed. A semiconductor laser is disclosed.

JP 2009-14701 A

  Here, the device characteristics of the semiconductor laser vary depending on the use environment and changes with time. In addition, the device characteristics of the semiconductor laser may differ due to variations (manufacturing variations) caused by the manufacturing process.

  In the measurement apparatus of Patent Document 1, when the difference in device characteristics between the first semiconductor laser and the second semiconductor laser used as the light source is large, an error is included in obtaining the distance and speed from the signal due to the self-coupling effect. As a result, measurement cannot be performed with high accuracy.

  One of the objects according to some aspects of the present invention is to provide a measuring apparatus capable of measuring with high accuracy. Another object of some aspects of the present invention is to provide a printer and an electronic apparatus including the measuring device.

The measuring device according to the present invention is
A first semiconductor laser that emits a first laser beam irradiated to a measurement object;
A second semiconductor laser that emits a second laser beam applied to the measurement object;
The first semiconductor laser is operated such that a period in which the wavelength of the first laser light continuously increases monotonously and a period in which the wavelength of the first laser light continuously decreases monotonously exists. One drive unit;
A second driving unit that operates the second semiconductor laser such that the phase of fluctuation of the wavelength of the second laser light and the phase of fluctuation of the wavelength of the first laser light are opposite to each other;
A first beat signal corresponding to interference light generated by a self-coupling effect caused by the first laser light emitted from the first semiconductor laser and the return light of the first laser light from the measurement target; A first detector for outputting a signal;
A second beat signal corresponding to interference light generated by a self-coupling effect caused by the second laser light emitted from the second semiconductor laser and the return light of the second laser light from the measurement target; A second detector for outputting a signal;
A calculation unit that obtains at least one of a distance to the measurement object and a speed of the measurement object based on the first signal and the second signal;
Including
The first semiconductor laser and the second semiconductor laser are provided on the same substrate.

  In such a measuring apparatus, the difference in device characteristics between the first semiconductor laser and the second semiconductor laser can be reduced. Therefore, such a measuring apparatus can perform measurement with high accuracy.

In the measuring device according to the present invention,
The first detection unit includes a first photodiode,
The second detection unit includes a second photodiode,
The first semiconductor laser, the second semiconductor laser, the first photodiode, and the second photodiode may be provided on the same substrate.

  In such a measuring apparatus, the apparatus can be reduced in size.

In the measuring device according to the present invention,
The first detection unit and the second detection unit have a common photodiode,
The first semiconductor laser, the second semiconductor laser, and the common photodiode may be provided on the same substrate.

  In such a measuring device, the configuration of the device can be simplified. Furthermore, in such a measuring apparatus, the apparatus can be reduced in size.

In the measuring device according to the present invention,
A condensing lens on which the first laser light and the second laser light are incident may be included.

  Since such a measuring apparatus has a condensing lens on which the first laser light and the second laser light are incident, compared with a case where a condensing lens is provided for each of the first semiconductor laser and the second semiconductor laser. Thus, the aperture of the condenser lens can be increased. Therefore, the laser light scattered by the measurement target can be efficiently captured, and the amount of return light incident on the first semiconductor laser and the amount of return light incident on the second semiconductor laser can be increased.

In the measuring device according to the present invention,
A distance between the first semiconductor laser and the measurement object along the chief ray of the first laser light; and the second semiconductor laser and the measurement object along the chief ray of the second laser light. The distance between may be equal.

  In such a measuring apparatus, the process for obtaining the distance to the measurement object and the speed of the measurement object can be facilitated.

In the measuring device according to the present invention,
A distance between the first semiconductor laser and the measurement object along the chief ray of the first laser light; and the second semiconductor laser and the measurement object along the chief ray of the second laser light. The distance between may be different.

In such a measuring apparatus, the distance between the first semiconductor laser and the measurement target along the chief ray of the first laser beam, and the second semiconductor laser and the measurement target along the chief ray of the second laser beam. The degree of freedom of arrangement of the first semiconductor laser and the second semiconductor laser with respect to the condensing lens is higher than that in the case where the distance between them is equal.

In the measuring device according to the present invention,
It straddles the optical path of the first laser light between the first semiconductor laser and the condenser lens and the optical path of the second laser light between the second semiconductor laser and the condenser lens. Including a beam splitter arranged to
The beam splitter reflects a part of the first laser beam emitted from the first semiconductor laser toward the first detection unit, and outputs a part of the second laser beam emitted from the second semiconductor laser. The part may be reflected toward the second detection part.

  In this manner, in the measurement apparatus, the first laser beam can be incident on the first detection unit while irradiating the measurement target with the first laser beam, and the second laser is irradiated while the measurement target is irradiated with the second laser beam. Light can be incident on the second detector.

In the measuring device according to the present invention,
A first condenser lens on which the first laser beam emitted from the first semiconductor laser is incident;
A second condenser lens on which the second laser light emitted from the second semiconductor laser is incident;
May be included.

  Such a measuring apparatus can perform measurement with high accuracy.

In the measuring device according to the present invention,
On the optical path of the first laser light between the first semiconductor laser and the first condensing lens, and on the optical path of the second laser light between the second semiconductor laser and the second condensing lens And a beam splitter arranged to straddle,
The beam splitter reflects a part of the first laser beam emitted from the first semiconductor laser toward the first detection unit, and outputs a part of the second laser beam emitted from the second semiconductor laser. The part may be reflected toward the second detection part.

  In this manner, in the measurement apparatus, the first laser beam can be incident on the first detection unit while irradiating the measurement target with the first laser beam, and the second laser is irradiated while the measurement target is irradiated with the second laser beam. Light can be incident on the second detector.

In the measuring device according to the present invention,
The first semiconductor laser and the second semiconductor laser may be surface emitting lasers.

  In such a measuring device, it is possible to produce a self-coupling effect while reducing the size of the device.

The printer according to the present invention is
Any one of the measurement devices described above is included.

  Such a printer can include a measuring device capable of measuring with high accuracy.

The electronic device according to the present invention is
Any one of the measurement devices described above is included.

  Such an electronic device can include a measuring device capable of performing highly accurate measurement.

The figure which shows the structure of the measuring device which concerns on 1st Embodiment. The figure for demonstrating the self-coupling effect. The graph which shows the drive current of a 1st semiconductor laser. The graph which shows the time change of the wavelength of a 1st laser beam. The graph which shows the output signal of a 1st detection part. The graph which shows a 1st beat signal. The graph which shows the time change of a self-coupling frequency. The graph which shows the drive current of a semiconductor laser. The graph which shows the self-coupling frequency f1, the self-coupling frequency f2, and the average value fa. Sectional drawing which shows a semiconductor laser and a photodiode typically. The figure which shows the structure of the measuring device which concerns on 2nd Embodiment. The figure for demonstrating the output signal of a photodiode. The figure which shows the structure of the measuring device which concerns on 3rd Embodiment. The figure which shows the structure of the measuring device which concerns on 4th Embodiment. The graph which shows the self-coupling frequency f1-f4 and these average value fa. The figure which shows the structure of the measuring device which concerns on 5th Embodiment. FIG. 10 is a perspective view illustrating a schematic configuration inside a printer according to a sixth embodiment. Sectional drawing which shows schematic structure inside the printer which concerns on 6th Embodiment. The figure which shows typically the robot system which concerns on 7th Embodiment. The functional block diagram of the electronic device which concerns on 8th Embodiment. FIG. 14 is a diagram illustrating an example of the appearance of a smartphone that is an example of an electronic apparatus. FIG. 6 is a diagram illustrating an example of an appearance of an arm-mounted portable device that is an example of an electronic device. The top view which shows a motor vehicle typically as a moving body which concerns on 9th Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. First embodiment 1.1. Configuration of Measuring Device First, the measuring device according to the first embodiment will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a measurement apparatus 100 according to the first embodiment.

  The measuring apparatus 100 functions as a distance meter that measures the distance D from the measurement object O using the self-coupling effect of the semiconductor laser. The measuring device 100 also functions as a speedometer that calculates the speed of the measuring object O using the self-coupling effect of the semiconductor laser. Note that the speed of the measuring object O measured by the measuring apparatus 100 is the speed of the measuring object O when the distance D is constant. By using the measuring device 100, at least one of the distance D to the measuring object O and the speed of the measuring object O can be measured.

  The measuring object O is not particularly limited as long as it can reflect laser light, and may be any of gas, liquid, and solid.

As shown in FIG. 1, the measurement apparatus 100 includes a first semiconductor laser 12, a second semiconductor laser 22, a beam splitter 30, a first detection unit 40, a second detection unit 50, and a first drive unit 60. And a second drive unit 70 and a calculation unit 80. The measuring device 100 further includes a condenser lens 2.

  The first semiconductor laser 12 is a surface emitting laser. The first semiconductor laser 12 is, for example, a vertical cavity surface emitting laser (VCSEL). A vertical cavity surface emitting laser is preferable as a light source of the measuring apparatus 100 because mode hops are unlikely to occur.

  The second semiconductor laser 22 is a surface emitting laser. The second semiconductor laser 22 is, for example, a vertical cavity surface emitting laser.

  The first semiconductor laser 12 and the second semiconductor laser 22 are provided on the same substrate (substrate 101). The first semiconductor laser 12 and the second semiconductor laser 22 are, for example, a distance (shortest distance) between the first semiconductor laser 12 and the measurement object O and a distance (shortest distance) between the second semiconductor laser 22 and the measurement object O. The distance) is equal. The distance D to the measurement object O is a distance (shortest distance) between the first semiconductor laser 12 (or the second semiconductor laser 22) and the measurement object O.

  The first laser light L1 emitted from the first semiconductor laser 12 and the second laser light L2 emitted from the second semiconductor laser 22 are incident on the condenser lens 2. That is, the condenser lens 2 is a condenser lens common to the first semiconductor laser 12 and the second semiconductor laser 22.

  The condensing lens 2 condenses the first laser light L1 and the second laser light L2 on the measurement object O. The condensing lens 2 condenses the first laser light L1 and the second laser light L2 at different positions of the measuring object O. Here, condensing light means collecting light in one place or in one direction.

  The first semiconductor laser 12 and the second semiconductor laser 22 are disposed outside the optical axis OA of the condenser lens 2. For example, the first semiconductor laser 12 and the second semiconductor laser 22 are disposed in the same plane orthogonal to the optical axis OA. The first semiconductor laser 12 and the second semiconductor laser 22 are arranged at symmetrical positions with respect to the optical axis OA in the plane. The traveling direction of the first laser light L1 emitted from the condenser lens 2 and the traveling direction of the second laser light L2 emitted from the condenser lens 2 are not parallel.

  The principal ray M1 of the first laser beam L1 and the principal ray M2 of the second laser beam L2 intersect each other. The principal ray M1 of the first laser light L1 and the principal ray M2 of the second laser light L2 are symmetric with respect to the optical axis OA of the condenser lens 2. The chief ray M1 of the first laser beam L1 and the chief ray M2 of the second laser beam L2 are inclined with respect to the measurement object O. The magnitude of the inclination angle of the principal ray M1 of the first laser beam L1 with respect to the measurement object O is equal to the magnitude of the inclination angle of the principal ray M2 of the second laser beam L2 with respect to the measurement object O. The distance D1 between the first semiconductor laser 12 and the measurement object O along the principal ray M1 of the first laser light L1, and the second semiconductor laser 22 and the measurement object O along the principal ray M2 of the second laser light L2. The distance D2 between the two is equal. The principal ray is a ray that goes out from a point outside the optical axis OA and passes through the center of the stop of the optical system (the center of the condenser lens 2).

  The condensing lens 2 captures a part of the first laser light L1 scattered by the measuring object O and makes it incident on the first semiconductor laser 12 as the first return light R1. Similarly, the condenser lens 2 captures a part of the second laser light L2 scattered by the measuring object O and makes it incident on the second semiconductor laser 22 as the second return light R2.

  In the first semiconductor laser 12, a phenomenon occurs in which the first laser light L1 and the first return light R1 interfere with each other and the output of the first laser light L1 increases or decreases. This phenomenon is called “self-coupling effect”. Similarly, in the second semiconductor laser 22, a phenomenon (self-coupling effect) in which the output of the second laser light L2 increases or decreases due to interference between the second laser light L2 and the second return light R2.

  The first drive unit 60 operates the first semiconductor laser 12. The first drive unit 60 outputs a drive signal for operating the first semiconductor laser 12. The drive signal is a drive current supplied to the first semiconductor laser 12.

  The first driving unit 60 repeats the first laser beam L1 so that the period in which the wavelength of the first laser beam L1 continuously increases and the period in which the wavelength of the first laser beam L1 continuously decreases monotonously exist. The semiconductor laser 12 is operated. For example, in the period in which the wavelength monotonously increases, the first driving unit 60 operates the first semiconductor laser 12 so that the wavelength increases at a constant change rate with respect to time. In addition, the first driving unit 60 operates the first semiconductor laser 12 so that the wavelength decreases at a constant change rate with respect to time during the period in which the wavelength monotonously decreases. The length of the period in which the wavelength of the first laser light L1 continuously increases monotonically is equal to the length of the period in which the wavelength of the first laser light L1 continuously decreases monotonously.

  The second drive unit 70 operates the second semiconductor laser 22. The second drive unit 70 outputs a drive signal (drive current) for operating the second semiconductor laser 22.

  The second driving unit 70 repeats the second laser beam L2 so that the period in which the wavelength of the second laser beam L2 continuously increases monotonously and the period in which the wavelength of the second laser beam L2 continuously decreases monotonously exist. The semiconductor laser 22 is operated. The length of the period in which the wavelength of the second laser light L2 continuously increases monotonically is equal to the length of the period in which the wavelength of the second laser light L2 continuously decreases monotonously. The second drive unit 70 operates the second semiconductor laser 22 so that the phase of the wavelength variation of the second laser light L2 and the phase of the wavelength variation of the first laser light L1 are in opposite phases. That is, the second driving unit 70 repeatedly has a period in which the wavelength of the second laser light L2 continuously increases monotonously and a period in which the wavelength of the second laser light L2 continuously decreases monotonously, and The second semiconductor laser 22 is operated so that the phase of the fluctuation is opposite in phase to the fluctuation of the wavelength of the first laser light L1.

  The beam splitter 30 is disposed between the first semiconductor laser 12 and the second semiconductor laser 22 and the condenser lens 2. More specifically, the beam splitter 30 is provided on the optical path of the first laser light L1 between the first semiconductor laser 12 and the condenser lens 2 and between the second semiconductor laser 22 and the condenser lens 2. It arrange | positions so that it may straddle on the optical path of 2 laser beam L2. Two beam splitters may be prepared, and the beam splitters may be disposed on the optical path of the first laser light L1 and the optical path of the second laser light L2, respectively.

  The beam splitter 30 reflects a part of the first laser light L1 emitted from the first semiconductor laser 12 toward the first detection unit 40. The beam splitter 30 transmits the remainder of the first laser light L1 emitted from the first semiconductor laser 12. Similarly, the beam splitter 30 reflects part of the second laser light L <b> 2 emitted from the second semiconductor laser 22 toward the second detection unit 50. The beam splitter 30 transmits the remainder of the second laser light L2 emitted from the second semiconductor laser 22.

The first detection unit 40 is configured to include a first photodiode 42. The first detector 40 receives the first laser light L1 from the beam splitter 30 and outputs a current signal corresponding to the received light intensity. Accordingly, the first detection unit 40 increases or decreases in intensity due to interference light generated by the self-coupling effect between the first laser light L1 and the first return light R1 (that is, interference between the first laser light L1 and the first return light R1). A current signal (first signal) including a waveform (first beat signal) corresponding to the first laser beam L1 which is beat light is output. The waveform of the first signal is a waveform in which the waveform similar to the drive current (drive signal) of the first semiconductor laser 12 and the waveform of the first beat signal due to the self-coupling effect are superimposed.

  The second detection unit 50 includes a second photodiode 52. The second detection unit 50 receives the second laser light L2 from the beam splitter 30, and outputs a current signal corresponding to the received light intensity. Therefore, the intensity of the second detection unit 50 increases or decreases due to interference light generated by the self-coupling effect between the second laser light L2 and the second return light R2 (that is, interference between the second laser light L2 and the second return light R2). A current signal (second signal) including a waveform (second beat signal) corresponding to the second laser light L2) which is beat light is output. The waveform of the second signal is a waveform in which the waveform similar to the drive current (drive signal) of the second semiconductor laser 22 and the waveform of the second beat signal due to the self-coupling effect are superimposed.

  The calculation unit 80 includes current-voltage conversion circuits 82a and 82b, filter circuits 84a and 84b, counting circuits 86a and 86b, and a calculation device 88.

  The current-voltage conversion circuit 82a converts the current signal output from the first detection unit 40 into a voltage signal. As a result, a voltage signal including the first beat signal due to the self-coupling effect can be obtained. This voltage signal has a waveform in which a waveform similar to the drive current of the first semiconductor laser 12 and the waveform of the first beat signal are superimposed.

  The filter circuit 84a removes a waveform component similar to the drive current of the first semiconductor laser 12 from the voltage signal output from the current-voltage conversion circuit 82a. Thereby, the first beat signal can be extracted.

  The counting circuit 86a counts the number of peaks (waves) of the first beat signal.

  The current-voltage conversion circuit 82b converts the current signal output from the second detection unit 50 into a voltage signal. Thereby, a voltage signal including the second beat signal due to the self-coupling effect can be obtained. This voltage signal has a waveform in which a waveform similar to the drive current of the second semiconductor laser 22 and the waveform of the second beat signal are superimposed.

  The filter circuit 84b removes a waveform component similar to the drive current of the second semiconductor laser 22 from the voltage signal output from the current-voltage conversion circuit 82b. Thereby, the second beat signal can be extracted.

  The counting circuit 86b counts the number of peaks (waves) of the second beat signal.

  The computing device 88 calculates the distance D1 (or distance D2, where distance D1 = distance D2) based on the counting result in the counting circuit 86a and the counting result in the counting circuit 86b, and the distance D from the measuring object O. And the speed of the measuring object O is calculated. The arithmetic device 88 is constituted by, for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and the like, and performs arithmetic processing according to various programs stored in a storage device (not shown).

1.2. Next, the measurement principle of the measurement device 100 will be described. FIG. 2 is a diagram for explaining the self-coupling effect.

  The output of the first laser light L1 increases or decreases due to the interference between the first return light R1 scattered by the measurement object O and returned to the first semiconductor laser 12 and the output light of the first semiconductor laser 12. (Self-bonding effect).

  In the first semiconductor laser 12, since the temperature increases and the resonator length increases by increasing the drive current, the wavelength increases. Utilizing this phenomenon, the wavelength of the first laser light L1 is periodically changed using the waveform of the drive current of the first semiconductor laser 12 as a triangular wave.

  FIG. 3 is a graph showing the drive current of the first semiconductor laser 12. As shown in FIG. 3, the driving current of the first semiconductor laser 12 repeatedly has a period in which the current continuously increases monotonously and a period in which the current continuously decreases monotonously. In the period in which the current monotonously increases, the current increases at a constant rate with respect to time. In the period in which the current monotonously decreases, the current decreases at a constant rate with respect to time. The length of the period in which the current continuously increases monotonically is equal to the length of the period in which the current continuously decreases monotonously. The drive current of the first semiconductor laser 12 is, for example, a triangular wave.

  When the first semiconductor laser 12 is operated in a region where the relationship between the drive current of the first semiconductor laser 12 and the wavelength of the first laser light L1 is linear, the waveform of the time change of the wavelength of the first laser light L1 is the drive It has the same waveform as the current.

  FIG. 4 is a graph showing the time change of the wavelength of the first laser beam L1.

  Similar to the waveform of the drive current shown in FIG. 3, the fluctuation of the wavelength of the first laser beam L1 has a period T1 in which the wavelength continuously increases monotonously and a period T2 in which the wavelength continuously decreases monotonously. It becomes a triangular wave.

  When the wavelength of the first laser beam L1 is varied, the output of the first laser beam L1 increases due to the self-coupling effect when the resonance condition is satisfied. Therefore, if the waveform of the wavelength variation of the first laser beam L1 is a triangular wave as shown in FIG. 4, the output (intensity) of the first laser beam L1 changes periodically. Therefore, a beat signal (first beat signal) that is a minute increase / decrease in the output of the laser beam due to resonance appears in the output signal of the first detection unit 40.

  FIG. 5 is a graph showing an output signal of the first detection unit 40 (first photodiode 42).

  As shown in FIG. 5, the output signal of the first detection unit 40 has a waveform in which the waveform similar to the drive current of the first semiconductor laser 12 and the waveform of the first beat signal are superimposed.

  FIG. 6 is a graph showing the first beat signal.

  As described above, the peak of the first beat signal (self-coupled signal) occurs due to an increase in the output of the first laser beam L1 due to the self-coupling effect when the resonance condition is satisfied. Therefore, the number of peaks (self-coupled signal) of the first beat signal corresponds to the number of wavelengths that satisfy the resonance condition, and the number increases as the distance D1 increases. Therefore, the distance D1 can be measured from the number of peaks of the first beat signal.

Here, the distance D1 is constant, the first laser beam L1 to the wavelength of the first laser beam L1 when interference satisfies the resonance condition of the first return beam R1 to the wavelength lambda ₁ and wavelength lambda ₂ (see FIG. 2 )
, When the wavelength lambda ₁ is changed by the wavelength lambda ₂ to the time interval Delta] t, the self-coupling frequency (beat frequency) fc of the first laser beam L1 at a certain time (moment) is represented by the following formula (1) .

fc = 4 × D1 × ((1 / λ ₁ ) − (1 / λ ₂ )) / Δt (1)
The self-coupling frequency fc is the frequency of the beat signal.

By measuring the relationship between the drive current of the first semiconductor laser 12 and the oscillation wavelength (the wavelength of the first laser beam L1) in advance and creating a table or the like, the wavelength λ ₁ and the wavelength λ ₂ at the time interval Δt are prepared. Can be requested. Therefore, the distance D1 can be calculated from the above equation (1) by measuring the self-coupling frequency fc.

  FIG. 7 is a graph showing the time change of the self-coupling frequency.

When the first semiconductor laser 12 is operated with a triangular wave driving current shown in FIG. 3, the self-coupling frequency fc slightly fluctuates (fluctuates) in accordance with the driving current waveform (triangular wave). Even if the oscillation wavelength of the first semiconductor laser 12 changes linearly with respect to the drive current, _(the reciprocal 1 / lambda ₂ wavelength lambda ₂₎ reciprocal 1 / lambda ₁ of the wavelength lambda ₁ for does not change linearly, self-binding The frequency fc fluctuates according to the time change of the drive current (oscillation wavelength). If the self-coupling frequency fc fluctuates, the measurement accuracy of the distance D1 deteriorates.

  With respect to such a problem, in the measurement apparatus 100, the phase of the fluctuation of the wavelength of the second laser light L2 emitted from the second semiconductor laser 22 is opposite to the phase of the fluctuation of the wavelength of the first laser light L1. The second semiconductor laser 22 is operated so as to be in phase.

  FIG. 8 is a graph showing the drive current I1 of the first semiconductor laser 12 and the drive current I2 of the second semiconductor laser 22.

  As shown in FIG. 8, the drive current I2 of the second semiconductor laser 22 has an opposite phase to the drive current I1 of the first semiconductor laser 12. Thereby, the wavelength variation of the second laser light L2 has an opposite phase to the wavelength variation of the first laser light L1.

  FIG. 9 is a graph showing the self-coupling frequency f1 obtained by detecting the first laser light L1, the self-coupling frequency f2 obtained by detecting the second laser light L2, and the average value fa.

  As shown in FIG. 9, the fluctuation of the self-coupling frequency f2 and the fluctuation of the self-coupling frequency f1 are in opposite phases. Therefore, this fluctuation is reduced by calculating the average value fa (= (f1 + f2) / 2) of the self-coupling frequency f2 and the self-coupling frequency f1. Therefore, a more accurate self-coupling frequency can be obtained. In addition, since the average value fa has a small variation at any moment, measurement can be performed at an arbitrary time.

  The distance D1 (or distance D2) can be calculated from the self-coupling frequency obtained in this manner using the above equation (1). And the distance D with the measuring object O is computable from the distance D1 (or distance D2).

Here, when the measuring object O is moving (however, the distance D is constant), the frequency of the return light from the measuring object O slightly changes (Doppler shift) due to the Doppler effect. The change in frequency due to the Doppler shift is proportional to the velocity of the measuring object O. Therefore, the speed of the measuring object O can be calculated by obtaining the difference between the self-coupling frequency when the measuring object O is stationary and the self-coupling frequency when the measuring object O is moving.

1.3. Operation of Measuring Device Next, the operation of the measuring device 100 will be described.

  The first drive unit 60 supplies the drive current I1 shown in FIG. 8 to the first semiconductor laser 12 so that the wavelength of the first laser light L1 continuously monotonously increases and the wavelength of the first laser light L1 is The first semiconductor laser 12 is operated so that there is a continuous monotonically decreasing period.

  The first laser light L1 emitted from the first semiconductor laser 12 is condensed by the condenser lens 2, irradiated onto the measurement object O, and scattered by the measurement object O. Part of the scattered first laser light L1 is incident on the first semiconductor laser 12 through the condenser lens 2 as the first return light R1. In the first semiconductor laser 12, the first return light R1 and the first laser light L1 interfere with each other, and the output of the first laser light L1 increases or decreases. A part of the first laser light L1 emitted from the first semiconductor laser 12 is reflected by the beam splitter 30 and enters the first detection unit 40.

  The first detection unit 40 receives the first laser light L1 and outputs a current signal corresponding to the received light intensity (see FIG. 5). The output signal of the first detection unit 40 has a waveform in which a waveform similar to the drive current of the first semiconductor laser 12 and the waveform of the first beat signal are superimposed.

  The current signal output from the first detection unit 40 is converted into a voltage signal by the current-voltage conversion circuit 82a. The filter circuit 84a removes a waveform component similar to the drive current of the first semiconductor laser 12 from the voltage signal output from the current-voltage conversion circuit 82a. As a result, a first beat signal is obtained (see FIG. 6). The counting circuit 86a counts the number of peaks (self-coupled signal) of the first beat signal at the time interval Δt.

  The second drive unit 70 supplies the drive current I2 shown in FIG. 8 to the second semiconductor laser 22, and the phase of the wavelength variation of the second laser beam L2 and the phase of the wavelength variation of the first laser beam L1 are detected. The second semiconductor laser 22 is operated so as to have an opposite phase.

  The processes of the second detection unit 50, the current-voltage conversion circuit 82b, the filter circuit 84b, and the counting circuit 86b are the same as the processes of the first detection unit 40, the current-voltage conversion circuit 82a, the filter circuit 84a, and the counting circuit 86a, respectively. The same is done.

The arithmetic unit 88 calculates an average value fa between the self-coupling frequency f1 based on the counting result in the counting circuit 86a and the self-coupling frequency f2 based on the counting result in the counting circuit 86b (see FIG. 9). Then, the distance D1 is calculated based on the average value fa. Specifically, the arithmetic unit 88 reads a table indicating the relationship between the drive current and the oscillation wavelength from a storage device (not shown) to obtain the wavelengths λ ₁ and λ ₂ . Then, the distance D1 is calculated by substituting the average value fa, the wavelength λ ₁ , the wavelength λ ₂ , and the time interval Δt as the self-coupling frequency fc into the above formula (1). The computing device 88 reads information on the tilt angle of the principal ray M1 of the first laser beam L1 with respect to the measurement object O from the storage device, and calculates the distance D from the calculated distance D1.

  Further, the arithmetic device 88 acquires a self-coupling frequency (average value fa) when the measuring object O is stationary and a self-coupling frequency (average value fa) when the measuring object O is moving. Then, the computing device 88 calculates the speed of the measuring object O based on the self-coupling frequency when the measuring object O is stationary and the self-coupling frequency when the measuring object O is moving.

1.4. Configuration of First Semiconductor Laser, Second Semiconductor Laser, First Detection Unit, and Second Detection Unit Next, the first semiconductor laser 12, the second semiconductor laser 22, the first photodiode 42, and the second photodiode 52 will be described. The configuration will be described. FIG. 10 is a cross-sectional view schematically showing the first semiconductor laser 12, the second semiconductor laser 22, the first photodiode 42, and the second photodiode 52.

  The first semiconductor laser 12, the second semiconductor laser 22, the first photodiode 42, and the second photodiode 52 are provided on the same substrate (substrate 101) as shown in FIG.

  The substrate 101 is, for example, an n-type GaAs substrate. The substrate 101 is not limited to a GaAs substrate, and may be another semiconductor substrate.

  The first semiconductor laser 12 is provided on the substrate 101. The first semiconductor laser 12 includes a first mirror layer 102, an active layer 103, a second mirror layer 104, a current confinement layer 105, a contact layer 106, an insulating layer 107, a first electrode 108, a second electrode, And an electrode 109.

The first mirror layer 102 is provided on the substrate 101. The first mirror layer 102 is, for example, a distributed Bragg reflection (DBR) mirror in which n-type Al _0.12 Ga _0.88 As layers and n-type Al _0.9 Ga _0.1 As layers are alternately stacked. It is. The active layer 103 is provided on the first mirror layer 102. The active layer 103 is, for example, a multiple quantum well in which three layers of a quantum well structure composed of an i-type In _0.06 Ga _0.94 As layer and an i-type Al _0.3 Ga _0.7 As layer are stacked. (MQW) structure. The second mirror layer 104 is provided on the active layer 103. The second mirror layer 104 is, for example, a distributed Bragg reflection type (DBR) in which p-type Al _0.12 Ga _0.88 As layers and p-type Al _0.9 Ga _0.1 As layers are alternately stacked. ) Mirror.

  The current confinement layer 105 is provided between the first mirror layer 102 and the second mirror layer 104. The current confinement layer 105 is an insulating layer in which an opening is formed.

  The contact layer 106 is provided on the second mirror layer 104. The contact layer 106 is, for example, a p-type GaAs layer.

  A part of the first mirror layer 102, the active layer 103, the second mirror layer 104, the current confinement layer 105, and the contact layer 106 constitute a columnar portion. The side surface of the columnar part is covered with an insulating layer 107. The insulating layer 107 is, for example, a polyimide resin.

  The first electrode 108 is provided on the contact layer 106. The shape of the first electrode 108 is a ring shape. The second electrode 109 is provided on the first mirror layer 102.

  The second mirror layer 104, the active layer 103, and the first mirror layer 102 constitute a vertical resonator type pin diode. When a forward voltage of a pin diode is applied between the first electrode 108 and the second electrode 109, recombination of electrons and holes occurs in the active layer 103, and light emission occurs. The light generated in the active layer 103 reciprocates between the first mirror layer 102 and the second mirror layer 104 (multiple reflection), and stimulated emission occurs at that time, and the intensity is amplified. When the optical gain exceeds the optical loss, laser oscillation occurs, and the first laser light L1 is emitted from the upper surface of the contact layer 106 in the vertical direction. That is, the first laser light L1 is emitted in the direction of the normal to the upper surface of the substrate 101.

  The first photodiode 42 is provided on the substrate 101. The first photodiode 42 includes a first contact layer 110, a light absorption layer 112, a second contact layer 114, an insulating layer 115, a third electrode 116, and a fourth electrode 118.

  The first contact layer 110 is provided on the substrate 101. The first contact layer 110 is, for example, an n-type GaAs layer. The light absorption layer 112 is provided on the first contact layer 110. The light absorption layer 112 is, for example, an i-type GaAs layer. The second contact layer 114 is provided on the light absorption layer 112. The second contact layer 114 is a p-type GaAs layer.

  A part of the first contact layer 110, the light absorption layer 112, and the second contact layer 114 constitute a columnar portion. The side surface of the columnar part is covered with an insulating layer 115. The insulating layer 115 is, for example, a polyimide resin.

  The third electrode 116 is provided on the second contact layer 114. The shape of the third electrode 116 is a ring shape. The fourth electrode 118 is provided on the first contact layer 110.

  The first contact layer 110, the light absorption layer 112, and the second contact layer 114 constitute a pin diode. The first laser beam L1 incident on the second contact layer 114 is incident on the light absorption layer 112. As a result of a part of the incident light being absorbed by the light absorption layer 112, photoexcitation occurs in the light absorption layer 112, and electrons and holes are generated. Therefore, the magnitude of the current is proportional to the intensity of light incident on the light absorption layer 112. That is, the intensity of the first laser light L1 can be known from the magnitude of the current flowing through the first photodiode 42.

  The configuration of the second semiconductor laser 22 is the same as the configuration of the first semiconductor laser 12 described above, and a description thereof is omitted. The configuration of the second photodiode 52 is the same as the configuration of the first photodiode 42, and the description thereof is omitted.

  An element separation unit 4 is provided between the elements. In the illustrated example, the element isolation unit 4 includes the first semiconductor laser 12 and the first photodiode 42, the first photodiode 42 and the second semiconductor laser 22, and the second semiconductor laser 22 and the second photo diode. They are respectively provided between the diodes 52. The element isolation unit 4 electrically isolates each element. The element isolation part 4 is a groove provided in the substrate 101.

  In the measuring apparatus 100, the first photodiode 12 and the second semiconductor laser 22 having a small difference in device characteristics (preferably the same device characteristics) and a first photodiode having a small difference in device characteristics (preferably the same device characteristics). 42 and the second photodiode 52 are used. As a result, the signal obtained by detecting the first laser light L1 emitted from the first semiconductor laser 12 by the first photodiode 42 and the second laser light L2 emitted from the second semiconductor laser 22 are converted into the second photo. Matching (matching) with a signal obtained by detection by the diode 42 can be improved, and fluctuations in the self-coupling frequency f1 and fluctuations in the self-coupling frequency f2 can be canceled. As a result, the self-coupling frequency can be obtained with high accuracy.

Here, the device characteristics of the semiconductor laser vary depending on the use environment and changes with time. In addition, the device characteristics of the semiconductor laser may differ due to variations (manufacturing variations) caused by the manufacturing process. For example, if the thickness of the active layer 103 varies during the manufacturing process, the device characteristics of the semiconductor laser also vary. First semiconductor laser 12
By providing the second semiconductor laser 22 and the second semiconductor laser 22 on the same substrate, it is possible to reduce the difference in device characteristics due to the use environment and the change over time of the first semiconductor laser 12 and the second semiconductor laser 22, and the difference in device characteristics due to manufacturing variations. Can be reduced.

  For example, when the relationship between the injection current and the oscillation wavelength differs between the first semiconductor laser 12 and the second semiconductor laser 22, the phase of the wavelength variation of the first laser light L1 and the wavelength variation of the second laser light L2 It is difficult to control the first semiconductor laser 12 and the second semiconductor laser 22 so that their phases are opposite to each other. Therefore, there is a case where the fluctuation of the self-coupling frequency f1 and the fluctuation of the self-coupling frequency f2 cannot be canceled and the self-coupling frequency cannot be obtained with high accuracy. In the measurement apparatus 100, as described above, the difference in device characteristics between the first semiconductor laser 12 and the second semiconductor laser 22 can be reduced. Therefore, in the measurement apparatus 100, the first semiconductor laser 12 and the second semiconductor laser can be easily reversed so that the phase of the wavelength variation of the first laser beam L1 and the phase of the wavelength variation of the second laser beam L2 are opposite to each other. 22 can be controlled, and the self-coupling frequency can be obtained with high accuracy.

  Even when the first semiconductor laser 12 and the second semiconductor laser 22 are provided on the same substrate, when the distance between the first semiconductor laser 12 and the second semiconductor laser 22 is large, the first semiconductor laser 12 is used. The difference between the device characteristics of the first semiconductor laser 12 and the second semiconductor laser 22 is larger than when the distance between the first semiconductor laser 22 and the second semiconductor laser 22 is small. Therefore, the distance (shortest distance) between the first semiconductor laser 12 and the second semiconductor laser 22 is preferably 200 μm or more and 300 μm or less. Thereby, the difference in device characteristics between the first semiconductor laser 12 and the second semiconductor laser 22 can be further reduced.

  In the illustrated example, the first photodiode 42 is arranged between the first semiconductor laser 12 and the second semiconductor laser 22, but the first semiconductor laser 12 and the second semiconductor laser 22 are adjacent to each other. You may arrange in. Thereby, the distance between the 1st semiconductor laser 12 and the 2nd semiconductor laser 22 can be made small, and the difference of the device characteristic of the 1st semiconductor laser 12 and the 2nd semiconductor laser 22 can be made smaller.

  Similar to the semiconductor laser described above, the device characteristics of the photodiode vary depending on the usage environment and changes over time. In addition, the device characteristics of the photodiode may differ due to variations (manufacturing variations) caused by the manufacturing process. For example, if the thickness of the light absorption layer 112 varies in the manufacturing process, the device characteristics of the photodiode also vary. By providing the first photodiode 42 and the second photodiode 52 on the same substrate, it is possible to reduce the difference in fluctuations in device characteristics due to the usage environment of the first photodiode 42 and the second photodiode 52 and changes over time, and manufacturing variations. The difference in device characteristics due to can be reduced.

  In addition, even when the first photodiode 42 and the second photodiode 52 are provided on the same substrate, when the distance between the first photodiode 42 and the second photodiode 52 is large, the first photodiode 42 is provided. The difference in device characteristics between the first photodiode 42 and the second photodiode 52 is larger than when the distance between the first photodiode 42 and the second photodiode 52 is small. In the illustrated example, the second semiconductor laser 22 is disposed between the first photodiode 42 and the second photodiode 52, but the first photodiode 42 and the second photodiode 52 are disposed adjacent to each other. May be. Thereby, the distance between the 1st photodiode 42 and the 2nd photodiode 52 can be made small, and the difference of the device characteristic of the 1st photodiode 42 and the 2nd photodiode 52 can be made smaller.

1.5. Features The measuring device 100 has the following features, for example.

  The measuring apparatus 100 includes a first semiconductor laser 12 and a second semiconductor laser 22, and the second drive unit 70 determines the phase of the wavelength variation of the second laser light L 2 and the wavelength of the first laser light L 1. The second semiconductor laser 22 is operated so that the phase of the fluctuation is opposite to the phase. Therefore, in the measuring apparatus 100, the fluctuation of the self-coupling frequency f2 and the fluctuation of the self-coupling frequency f1 are in opposite phases. Therefore, in the measuring apparatus 100, the fluctuation of the self-coupling frequency f1 and the fluctuation of the self-coupling frequency f2 can be canceled, and the influence of the fluctuation generated in the self-coupling frequency can be reduced. As a result, the measuring apparatus 100 can obtain a higher-accuracy self-coupling frequency, and therefore can perform more accurate measurement. In addition, since the average value fa has a small variation at any moment, measurement can be performed at an arbitrary time.

  In the measuring apparatus 100, the first semiconductor laser 12 and the second semiconductor laser 22 are provided on the same substrate (substrate 101). Therefore, the difference in device characteristics between the first semiconductor laser 12 and the second semiconductor laser 22 can be reduced.

  In the measuring apparatus 100, the first semiconductor laser 12, the second semiconductor laser 22, the first photodiode 42, and the second photodiode 52 are provided on the same substrate (substrate 101). Therefore, in the measuring apparatus 100, the apparatus can be reduced in size.

  The measuring apparatus 100 includes a condenser lens 2 on which the first laser light L1 and the second laser light L2 are incident. Therefore, in the measuring apparatus 100, for example, a lens having a long focal length and a large aperture is used as the condensing lens 2 as compared with a case where a condensing lens is provided for each of the first semiconductor laser 12 and the second semiconductor laser 22. Can do. Therefore, the laser light scattered by the measuring object O can be efficiently captured, and the light quantity of the first return light R1 and the light quantity of the second return light R2 can be increased. As a result, in the measuring apparatus 100, the SN ratio of the first beat signal included in the output signal of the first detection unit 40 and the SN ratio of the second beat signal included in the output signal of the second detection unit 50 can be increased. it can.

  Further, in the measuring apparatus 200, a lens having a long focal length and a large aperture can be used as the condensing lens 2, so that the alignment between the first semiconductor laser 12 and the condensing lens 2 and the second semiconductor laser 22 can be performed. Positioning with the condenser lens 2 is easy. As described above, since the first semiconductor laser 12 and the second semiconductor laser 22 are provided on the same substrate, the first semiconductor laser 12 and the second semiconductor laser 22 are close to each other. Therefore, for example, when a condensing lens is provided for each of the first semiconductor laser 12 and the second semiconductor laser 22, a lens having a short focal length and a small aperture must be used as the condensing lens. Therefore, high accuracy is required for the alignment between the first semiconductor laser 12 and the condenser lens and the alignment between the second semiconductor laser 22 and the condenser lens.

  In the measuring apparatus 100, the distance D1 between the first semiconductor laser 12 and the measurement object O along the principal ray M1 of the first laser light L1, and the second along the principal ray M2 of the second laser light L2. The distance D2 between the semiconductor laser 22 and the measurement object O is equal. Therefore, in the measuring apparatus 100, for example, compared with the case where the distance D1 and the distance D2 are different, the process for obtaining the distance D to the measuring object O and the speed of the measuring object O can be facilitated. That is, in the measuring apparatus 100, the processing of the calculation unit 80 can be facilitated.

In the measurement apparatus 100, the light of the second laser light L2 between the first semiconductor laser 12 and the condensing lens 2 on the optical path of the first laser light L1 and between the second semiconductor laser 22 and the condensing lens 2 is measured. A beam splitter 30 is disposed on the road so as to straddle the road. Therefore, in the measuring apparatus 100, the first laser light L1 is first emitted while the measurement object O is irradiated with the first laser light L1.
The second laser beam L2 can be incident on the detection unit 40 (first photodiode 42) and the second laser beam L2 is irradiated to the measurement object O while the second laser beam L2 is irradiated to the second detection unit 50 (second photodiode 52). Can be made incident.

  In the measuring apparatus 100, the first semiconductor laser 12 and the second semiconductor laser 22 are surface emitting lasers. Therefore, in the measuring apparatus 100, the self-coupling effect can be generated while reducing the size of the apparatus.

2. Second Embodiment Next, a measuring apparatus according to a second embodiment will be described with reference to the drawings. FIG. 11 is a diagram illustrating a configuration of a measurement apparatus 200 according to the second embodiment. Hereinafter, in the measuring apparatus 200, members having the same functions as the constituent members of the measuring apparatus 100 described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the measurement apparatus 100 described above, as shown in FIG. 1, the first detection unit 40 has a first photodiode 42, and the second detection unit 50 has a second photodiode 52.

  On the other hand, in the measuring apparatus 200, as shown in FIG. 11, the first detection unit 40 and the second detection unit 50 have a common photodiode 210.

  In the measuring apparatus 200, the beam splitter 30 reflects part of the first laser light L1 and part of the second laser light L2 toward the photodiode 210. The photodiode 210 receives the first laser light L1 and the second laser light L2 from the beam splitter 30, and outputs a current signal corresponding to the received light intensity.

  The first semiconductor laser 12, the second semiconductor laser 22, and the photodiode 210 are provided on the same substrate (substrate 101). Therefore, the apparatus can be reduced in size. The configuration of the photodiode 210 is the same as the configuration of the first photodiode 42 described above, and a description thereof is omitted.

  FIG. 12 is a diagram for explaining an output signal of the photodiode 210.

The output signal of the photodiode 210 is obtained by superimposing the waveform of the output signal I ₄₂ of the first photodiode 42 (see FIG. 1) and the waveform of the output signal I ₅₂ of the second photodiode 52 (see FIG. 1). It becomes a waveform. Therefore, the waveform similar to the drive current of the first semiconductor laser 12 and the waveform similar to the drive current of the second semiconductor laser 22 cancel each other. Furthermore, the fluctuation component of the self-coupling frequency in the first laser beam L1 and the fluctuation component of the self-coupling frequency in the second laser beam L2 cancel each other. Therefore, it is possible to reduce the influence of fluctuation occurring in the self-coupling frequency, and to obtain a more accurate self-coupling frequency.

The output signal I ₂₁₀ of the photodiode 210 has a waveform in which the waveform of the first beat signal and the waveform of the second beat signal are superimposed.

  The calculation unit 80 includes a current-voltage conversion circuit 202, an FFT (Fast Fourier Transform) circuit 204, and a calculation device 206.

  The current-voltage conversion circuit 202 converts the current signal output from the photodiode 210 into a voltage signal. As a result, a voltage signal including the first beat signal and the second beat signal can be obtained.

  The FFT circuit 204 measures the frequency of the first beat signal and the frequency of the second beat signal from the voltage signal output from the current-voltage conversion circuit 202 using FFT.

  The arithmetic unit 206 calculates the distance D1 (or distance D2) based on the frequency of the first beat signal (self-coupling frequency f1) and the frequency of the second beat signal (self-coupling frequency f2) measured by the FFT circuit 204. Then, the distance D is calculated. In addition, the arithmetic unit 206 calculates the speed of the measuring object O based on the self-coupling frequency when the measuring object O is stationary and the self-coupling frequency when the measuring object O is moving.

  According to the measuring device 200, the same effects as the measuring device 100 described above can be achieved. Furthermore, according to the measuring apparatus 200, the first detection unit 40 and the second detection unit 50 have the common photodiode 210. Therefore, in the measuring device 200, the configuration of the device can be simplified.

3. Third Embodiment Next, a measuring apparatus according to a third embodiment will be described with reference to the drawings. FIG. 13 is a diagram illustrating a configuration of a measurement apparatus 300 according to the third embodiment. Hereinafter, in the measuring apparatus 300, members having the same functions as the constituent members of the measuring apparatuses 100 and 200 described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the measurement apparatus 100 described above, as shown in FIG. 1, the distance D1 between the first semiconductor laser 12 and the measurement object O along the principal ray M1 of the first laser light L1, and the main of the second laser light L2 The distance D2 between the second semiconductor laser 22 and the measuring object O along the light beam M2 was equal.

  On the other hand, in the measuring apparatus 300, as shown in FIG. 13, the distance D1 between the first semiconductor laser 12 and the measurement object O along the principal ray M1 of the first laser light L1, and the second laser light. The distance D2 between the second semiconductor laser 22 and the measurement object O along the principal ray M2 of L2 is different.

  The principal ray M1 of the first laser light L1 and the principal ray M2 of the second laser light L2 are not symmetrical with respect to the optical axis OA of the condenser lens 2. The magnitude of the tilt angle of the chief ray M1 of the first laser beam L1 with respect to the measurement object O is different from the magnitude of the tilt angle of the chief ray M2 of the second laser beam L2 with respect to the measurement target O.

  The output signal of the first photodiode 42 and the output signal of the second photodiode 52 are input to the current-voltage conversion circuit 202. Therefore, the current signal input to the current-voltage conversion circuit 202 is a waveform in which the waveform of the first beat signal and the waveform of the second beat signal are superimposed, as in the measurement apparatus 200 described above (see FIG. 12). .

  In the measurement apparatus 300, the configuration of the calculation unit 80 is the same as that of the measurement apparatus 200. The arithmetic device 206 calculates the distance D1 and the distance D2, respectively, and calculates the distance D to the measuring object O based on at least one of the distance D1 and the distance D2. The distance D may be an average of the distance D calculated from the distance D1 and the distance D calculated from the distance D2, for example. Further, the calculation unit 80 calculates the speed of the measurement object O.

  Although not shown, in the measurement apparatus 300, the first detection unit 40 and the second detection unit 50 may have a common photodiode 210, similarly to the measurement apparatus 200 shown in FIG.

  The measuring device 300 can provide the same operational effects as the measuring device 100 described above. Furthermore, in the measuring apparatus 300, the distance D1 and the distance D2 are different. Therefore, in the measuring apparatus 300, for example, the degree of freedom of arrangement of the first semiconductor laser 12 and the second semiconductor laser 22 with respect to the condenser lens 2 is higher than when the distance D1 and the distance D2 are equal.

4). Fourth Embodiment Next, a measurement apparatus according to a fourth embodiment will be described with reference to the drawings. FIG. 14 is a diagram illustrating a configuration of a measurement apparatus 400 according to the fourth embodiment. Hereinafter, in the measuring device 400, members having the same functions as the constituent members of the measuring devices 100, 200, and 300 described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  The measuring apparatus 100 described above includes two semiconductor lasers (the first semiconductor laser 12 and the second semiconductor laser 22) as shown in FIG.

  In contrast, the measurement apparatus 400 includes four semiconductor lasers (a first semiconductor laser 12, a second semiconductor laser 22, a third semiconductor laser 412, and a fourth semiconductor laser 422) as shown in FIG. Yes.

  As shown in FIG. 14, the measurement device 400 includes a first semiconductor laser 12, a second semiconductor laser 22, a third semiconductor laser 412, a fourth semiconductor laser 422, a beam splitter 30, and a first detection unit 40. The second detection unit 50, the third detection unit 440, the fourth detection unit 450, the first drive unit 60, the second drive unit 70, the third drive unit 460, and the fourth drive unit 470. And an arithmetic unit 80.

  The configurations of the third semiconductor laser 412 and the fourth semiconductor laser 422 are the same as those of the first semiconductor laser 12 described above. The first laser beam L1 emitted from the first semiconductor laser 12, the second laser beam L2 emitted from the second semiconductor laser 22, the third laser beam L3 emitted from the third semiconductor laser 412, and the fourth laser beam The fourth laser light L4 emitted from L4 enters the condenser lens 2. That is, the condensing lens 2 is a condensing lens common to the first semiconductor laser 12, the second semiconductor laser 22, the third semiconductor laser 412, and the fourth semiconductor laser 422.

  The first semiconductor laser 12, the second semiconductor laser 22, the third semiconductor laser 412, and the fourth semiconductor laser 422 are provided on the same substrate (substrate 101). In the illustrated example, for convenience, the first semiconductor laser 12, the second semiconductor laser 22, the third semiconductor laser 412, and the fourth semiconductor laser 422 are shown in a line. In the semiconductor laser 12, the second semiconductor laser 22, the third semiconductor laser 412, and the fourth semiconductor laser 422, the distances between the semiconductor laser and the measuring object O along the principal ray (not shown) are equal to each other. It shall be arranged in.

  The third driving unit 460 operates the third semiconductor laser 412. The third driving unit 460 operates the third semiconductor laser 412 so that the phase of the wavelength variation of the third laser light L3 and the phase of the wavelength variation of the first laser light L1 are shifted by 90 °.

  The fourth drive unit 470 operates the fourth semiconductor laser 422. The fourth driving unit 470 operates the fourth semiconductor laser 422 so that the phase of the wavelength variation of the fourth laser light L4 and the phase of the wavelength variation of the first laser light L1 are shifted by 270 °.

That is, in the measuring apparatus 400, the phase of the wavelength variation of the first semiconductor laser 12, the phase of the wavelength variation of the second semiconductor laser 22, the phase of the wavelength variation of the third semiconductor laser 412,
And the phase of the fluctuation of the wavelength of the fourth semiconductor laser 422 is shifted by 90 ° from each other.

  The beam splitter 30 reflects a part of the first laser light L1 emitted from the first semiconductor laser 12 toward the first detection unit 40, and provides a part of the second laser light L2 emitted from the second semiconductor laser 22. Part is reflected toward the second detection unit 50. The beam splitter 30 further reflects a part of the third laser light L3 emitted from the third semiconductor laser 412 toward the third detection unit 440, and the fourth laser light L4 emitted from the fourth semiconductor laser 422. Is reflected toward the fourth detection unit 450.

  The third detection unit 440 includes a third photodiode 442. The third detection unit 440 generates interference light generated by the self-coupling effect between the third laser light L3 and the third return light R3 (that is, beat light whose intensity increases or decreases due to interference between the third laser light L3 and the third return light R3). Current signal (third signal) including a waveform (third beat signal) corresponding to the third laser beam L3).

  The fourth detection unit 450 includes a fourth photodiode 452. The fourth detection unit 450 includes interference light generated by the self-coupling effect between the fourth laser light L4 and the fourth return light R4 (that is, beat light whose intensity increases or decreases due to interference between the fourth laser light L4 and the fourth return light R4). Current signal (fourth signal) including a waveform (fourth beat signal) corresponding to the fourth laser beam L4).

  The arithmetic unit 80 includes current-voltage conversion circuits 82a, 82b, 82c, and 82d, filter circuits 84a, 84b, 84c, and 84d, counting circuits 86a, 86b, 86c, and 86d, and an arithmetic device 88. .

  The current-voltage conversion circuit 82c, the filter circuit 84c, and the counting circuit 86c perform processing on the output signal of the third detection unit 440 (third photodiode 442). The current-voltage conversion circuit 82d, the filter circuit 84d, and the counting circuit 86d perform processing on the output signal of the fourth detection unit 450 (fourth photodiode 452).

  The arithmetic unit 88 obtains the self-coupling frequency based on the counting result in the counting circuit 86a, the counting result in the counting circuit 86b, the counting result in the counting circuit 86c, and the counting result in the counting circuit 86d, and the measurement object O The distance D and the velocity of the measuring object O are calculated.

  FIG. 15 is obtained by detecting the self-coupling frequency f1 obtained by detecting the first laser light L1, the self-coupling frequency f2 obtained by detecting the second laser light L2, and the third laser light L3. It is a graph which shows self-coupling frequency f3, self-coupling frequency f4 obtained by detecting the 4th laser beam L4, and these average values fa.

  As shown in FIG. 15, the fluctuation of the self-coupling frequency f1, the fluctuation of the self-coupling frequency f2, the fluctuation of the self-coupling frequency f3, and the fluctuation of the self-coupling frequency f4 cancel each other, so that the average value fa ((f1 + f2 + f3 + f4) / In 4), this fluctuation is reduced. Therefore, the measurement accuracy can be further increased by calculating the average value fa by the arithmetic device 88.

In the above description, an example in which the measurement apparatus 400 includes four semiconductor lasers (the first semiconductor laser 12, the second semiconductor laser 22, the third semiconductor laser 412, and the fourth semiconductor laser 422) has been described. You may have the above semiconductor lasers. For example, when the measuring apparatus 400 has n semiconductor lasers, the phase of the wavelength variation of each semiconductor laser may be shifted by 2π / n. Note that n is preferably an even number. This is because when n is an even number, the effect of reducing fluctuations in the self-coupling frequency is greater than when n is an odd number.

  The measuring device 400 can achieve the same effects as the measuring device 100 described above. Furthermore, since the measuring apparatus 400 has four semiconductor lasers (first semiconductor laser 12, second semiconductor laser 22, third semiconductor laser 412, and fourth semiconductor laser 422), two semiconductor lasers (first semiconductor laser). 12 and the second semiconductor laser 22 (see FIG. 1), the measurement accuracy can be further increased.

  Although not shown, in the measurement apparatus 400, the first detection unit 40, the second detection unit 50, the third detection unit 440, and the fourth detection unit 450 have a common photodiode 210 (see FIG. 11). It may be.

  Although not shown, in the measuring apparatus 400, the first semiconductor laser 12, the second semiconductor laser 22, the third semiconductor laser 412, and the fourth semiconductor laser 422 are the semiconductor laser along the principal ray, the measurement object O, and the like. They may be arranged such that the distance between them is different from each other.

5. Fifth Embodiment Next, a measurement apparatus according to a fifth embodiment will be described with reference to the drawings. FIG. 16 is a diagram illustrating a configuration of a measurement device 405 according to the fifth embodiment. Hereinafter, in the measuring device 405, members having the same functions as the constituent members of the measuring devices 100, 200, 300, and 400 described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  The measuring apparatus 100 described above has the condenser lens 2 on which the first laser light L1 and the second laser light L2 are incident, as shown in FIG.

  On the other hand, as shown in FIG. 16, the measuring device 405 is emitted from the first condenser lens 2 a on which the first laser light L <b> 1 emitted from the first semiconductor laser 12 is incident and the second semiconductor laser 22. And a second condenser lens 2b on which the second laser beam L2 is incident.

  The 1st condensing lens 2a condenses the 1st laser beam L1 to the measuring object O. FIG. The first condenser lens 2a may focus the first laser light L1 in one place, or the first laser light L1 may be parallel light. The first semiconductor laser 12 is disposed on the optical axis OA1 of the first condenser lens 2a.

  The 2nd condensing lens 2b condenses the 2nd laser beam L2 on the measuring object O. FIG. The second condenser lens 2b may focus the second laser light L2 in one place, or may use the second laser light L2 as parallel light. The second semiconductor laser 22 is disposed on the optical axis OA2 of the second condenser lens 2b.

  The optical axis OA1 of the first condenser lens 2a and the optical axis OA2 of the second condenser lens 2b are parallel.

  The traveling direction of the first laser light L1 emitted from the first condenser lens 2a and the traveling direction of the second laser light L2 emitted from the second condenser lens 2b are parallel. A distance D1 between the first semiconductor laser 12 and the measuring object O along the optical axis OA of the first laser light L1 is equal to the distance D. Further, the distance D2 between the second semiconductor laser 22 and the measuring object O along the optical axis OA of the second laser light L2 is equal to the distance D.

The first condenser lens 2a captures a part of the first laser light L1 scattered by the measuring object O and makes it incident on the second semiconductor laser 22 as the first return light R1. The second condenser lens 2b captures a part of the second laser light L2 scattered by the measuring object O and makes it incident on the second semiconductor laser 22 as the second return light R2.

  The beam splitter 30 includes a second laser on the optical path of the first laser light L1 between the first semiconductor laser 12 and the first condenser lens 2a, and between the second semiconductor laser 22 and the second condenser lens 2b. It arrange | positions so that it may straddle on the optical path of the light L2. The beam splitter 30 reflects a part of the first laser light L1 emitted from the first semiconductor laser 12 toward the first detection unit 40 (first photodiode 42), and is emitted from the second semiconductor laser 22. A part of the second laser beam L2 is reflected toward the second detection unit 50 (second photodiode 52).

  In the measurement device 405, the configuration of the calculation unit 80 is the same as the configuration of the calculation unit 80 of the measurement device 100. Note that in the measuring device 405, the distance D1 and the distance D2 are equal to the distance D. Therefore, the processing device 88 does not need to calculate the distance D from the distance D1 or the distance D2.

  The measuring device 405 can achieve the same effects as the measuring device 100 described above.

  Furthermore, since the measuring device 405 includes the first condenser lens 2a and the second condenser lens 2b, the degree of freedom in arrangement of the first semiconductor laser 12 and the second semiconductor laser 22 is high. For example, when the condensing lens 2 common to the first semiconductor laser 12 and the second semiconductor laser 22 is provided (see, for example, FIG. 1), the distance between the first semiconductor laser 12 and the second semiconductor laser 22 is the condensing lens. Limited by the size of 2. The measuring device 405 has no such limitation.

  In the measuring device 405, the beam splitter 30 can cause the first laser beam L1 to be incident on the first detection unit 40 while irradiating the measurement target O with the first laser beam L1. The second laser beam L2 can be incident on the second detector 50 while irradiating the two laser beams L2.

  Although not shown, in the measurement device 405, the first detection unit 40 and the second detection unit 50 may have a common photodiode 210 as in the measurement device 200 shown in FIG.

6). Sixth Embodiment Next, a printer (liquid ejection device) according to a sixth embodiment will be described with reference to the drawings. FIG. 17 is a perspective view illustrating a schematic configuration inside a printer 500 according to the sixth embodiment.

  The printer 500 includes a measuring device according to the present invention. Hereinafter, a case where the printer 500 includes the measurement device 100 as a measurement device according to the present invention will be described.

  The printer 500 ejects ink according to image data supplied from an external host computer, thereby forming an ink dot group on a print medium such as paper, and thereby an image (character, character) corresponding to the image data. Inkjet printer that prints graphics (including graphics).

As shown in FIG. 17, the printer 500 includes a moving mechanism 503 that moves (reciprocates) the moving member 502 in the main scanning direction.

  The moving mechanism 503 includes a carriage motor 531 serving as a driving source for the moving member 502, a carriage guide shaft 532 fixed at both ends, a timing belt that extends substantially parallel to the carriage guide shaft 532 and is driven by the carriage motor 531. 533.

  The carriage 524 of the moving member 502 is supported by the carriage guide shaft 532 so as to be able to reciprocate, and is fixed to a part of the timing belt 533. Therefore, when the timing belt 533 travels forward and backward by the carriage motor 531, the moving member 502 is guided by the carriage guide shaft 532 and reciprocates.

  Further, a head unit 520 is provided in a portion of the moving member 502 that faces the print medium P. The head unit 520 is for ejecting ink droplets (droplets) from a large number of nozzles, and is configured to be supplied with various control signals and the like via a flexible cable 590.

  The printer 500 includes a transport mechanism 504 that transports the print medium P on the platen 540 in the sub-scanning direction. The transport mechanism 504 includes a transport motor 541 that is a driving source, and a transport roller 542 that is rotated by the transport motor 541 and transports the print medium P in the sub-scanning direction.

  When the print medium P is conveyed by the conveyance mechanism 504, the head unit 520 ejects ink droplets onto the print medium P, so that an image is formed on the surface of the print medium P.

  FIG. 18 is a cross-sectional view illustrating a schematic configuration inside the printer 500.

  The measuring device 100 is provided as a distance meter for measuring the distance at a portion of the moving member 502 facing the print medium P. The measuring device 100 measures the distance from the print medium P. The measurement result obtained by the measurement apparatus 100 is sent to a control unit (not shown) of the printer 500, and the thickness of the print medium P is calculated from the measurement result. The control unit controls the timing of ejecting ink droplets based on the calculation result of the thickness of the print medium P.

  A casing (not shown) of the printer 500 is provided with a measuring device 100 as a speedometer for measuring the feeding speed (speed in the sub-scanning direction) of the printing medium P at a position facing the printing medium P. Yes. The measuring device 100 measures the feeding speed of the print medium P. The measurement result obtained by the measuring apparatus 100 is sent to the control unit. A control part controls the timing which discharges an ink drop based on this measurement result.

7). Seventh Embodiment Next, a robot system according to a seventh embodiment will be described with reference to the drawings. FIG. 19 is a diagram schematically showing a robot system 600 according to the seventh embodiment.

  The robot system 600 includes a measuring device according to the present invention. Below, the case where the robot system 600 includes the measuring device 100 as a measuring device according to the present invention will be described.

The robot system 600 includes a robot 602 and a control device 604 that controls the operation of the robot 602. The robot system 600 can be used in a manufacturing process for manufacturing “objects” such as precision devices such as watches and mobile phones and parts thereof. In the present embodiment, the case where an object 680 that is a plate-like member having a quadrangular shape in plan view is used as the “object” will be described below as an example.

  The robot 602 in the present embodiment performs an operation of discharging the discharge object 690 to the object 680.

  The robot 602 is, for example, a 6-axis vertical articulated robot. The robot 602 includes a base 610 and a movable part 620. The movable unit 620 includes a robot arm 612 connected to the base 610, a force detection unit 614 provided at the distal end of the robot arm 612, and a dispenser 616 as an end effector provided at the distal end side of the force detection unit 614. (Discharge part). The force detector 614 is a force detector that detects a force or moment applied to the tip of the dispenser 616.

  The dispenser 616 is provided with a measuring device 100. The measuring device 100 functions as a distance meter that measures the distance to the object 680. In the robot system 600, for example, during the operation of the robot 602, the tip of the dispenser 616 with respect to the object 680 can be moved in the vertical direction based on the measurement result of the measurement device 100. That is, in the robot system 600, the position of the tip of the dispenser 616 with respect to the object 680 can be fed back in real time during the operation of the robot 602. Thereby, the robot 602 can perform an appropriate operation on the object 680 based on the output of the measurement apparatus 100.

8). Eighth Embodiment Next, an electronic apparatus according to an eighth embodiment will be described with reference to the drawings. The measuring apparatus according to the present invention can also be applied to electronic devices other than the printer 500 and the robot system 600 described above.

  FIG. 20 is a functional block diagram of an electronic device 1000 according to the eighth embodiment.

  The electronic device 1000 includes a measuring device according to the present invention. Below, the case where the measuring apparatus 100 is included as a measuring apparatus which concerns on this invention is demonstrated.

  The electronic device 1000 further includes an arithmetic processing unit (CPU) 1020, an operation unit 1030, a ROM (Read Only Memory) 1040, a RAM (Random Access Memory) 1050, a communication unit 1060, and a display unit 1070. Note that the electronic device of the present embodiment may have a configuration in which some of the components (each unit) in FIG. 20 are omitted or changed, or other components are added.

  The arithmetic processing unit 1020 performs various types of calculation processing and control processing in accordance with programs stored in the ROM 1040 or the like. Specifically, the arithmetic processing device 1020 performs various processes according to the output signal of the measurement device 100 and the operation signal from the operation unit 1030, the process of controlling the communication unit 1060 to perform data communication with the external device, A process of transmitting a display signal for displaying various information on the display unit 1070 is performed.

  The operation unit 1030 is an input device including operation keys, button switches, and the like, and outputs an operation signal corresponding to an operation by the user to the arithmetic processing device 1020.

  The ROM 1040 stores programs, data, and the like for the arithmetic processing unit 1020 to perform various calculation processes and control processes.

  The RAM 1050 is used as a work area of the arithmetic processing device 1020, and programs and data read from the ROM 1040, data input from the measuring device 100, data input from the operation unit 1030, and the arithmetic processing device 1020 according to various programs. The result of the operation that has been executed is temporarily stored.

  The communication unit 1060 performs various controls for establishing data communication between the arithmetic processing device 1020 and an external device.

  The display unit 1070 is a display device configured by an LCD (Liquid Crystal Display) or the like, and displays various types of information based on a display signal input from the arithmetic processing device 1020. The display unit 1070 may be provided with a touch panel that functions as the operation unit 1030.

  Various electronic devices can be considered as such an electronic device 1000, for example, personal computers (for example, mobile personal computers, laptop personal computers, tablet personal computers), mobile terminals such as smartphones and mobile phones, Digital still cameras, televisions, video cameras, car navigation devices, electronic game devices, game controllers, crime prevention TV monitors, electronic binoculars, medical devices (for example, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic devices) , Electronic endoscope), various measuring instruments, instruments (eg, vehicle, aircraft, ship instruments), flight simulator, head mounted display, motion tracing, motion tracking, motion control Ra, PDR (Pedestrian reckoning), and the like.

  FIG. 21 is a diagram illustrating an example of the appearance of a smartphone that is an example of the electronic apparatus 1000. A smartphone that is the electronic apparatus 1000 includes a button as the operation unit 1030 and an LCD as the display unit 1070.

  FIG. 22 is a diagram illustrating an example of the appearance of an arm-mounted portable device (wearable device) that is an example of the electronic device 1000. The wearable device that is the electronic device 1000 includes an LCD as the display unit 1070. The display unit 1070 may be provided with a touch panel that functions as the operation unit 1030.

  Moreover, the portable device which is the electronic device 1000 includes a position sensor such as a GPS receiver (GPS), and can measure the movement distance and movement locus of the user.

9. Ninth Embodiment Next, a moving body according to a ninth embodiment will be described with reference to the drawings. FIG. 23 is a top view schematically showing an automobile as the moving body 1100 according to the ninth embodiment.

  The moving body according to the present embodiment includes the measuring device according to the present invention. Below, the moving body containing the measuring apparatus 100 is demonstrated as a measuring apparatus which concerns on this invention.

  The measuring apparatus 100 is incorporated in, for example, a collision prevention apparatus for the moving body 1100, and functions as a distance meter that measures the distance from an object (such as an automobile or an obstacle). In the moving body 1100, a warning can be given to the driver or the moving body 1100 can be stopped based on the measurement result of the measuring device 100 during the movement.

The mobile body 1100 according to the present embodiment further includes an engine system, a brake system,
It includes a controller 1120 that performs various controls such as a keyless entry system, a controller 1130, a controller 1140, a battery 1150, and a backup battery 1160. Note that the moving body 1100 according to the present embodiment may be configured such that some of the components (each unit) shown in FIG. 23 are omitted or changed, or other components are added.

  As such a moving body 1100, various moving bodies are conceivable, and examples thereof include automobiles (including electric automobiles), airplanes such as jets and helicopters, ships, rockets, and artificial satellites.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation implementation is possible within the range of the summary of this invention.

  For example, in the first embodiment described above, as illustrated in FIG. 1, the case where the first detection unit 40 includes the first photodiode 42 has been described. However, the first detection unit 40 outputs the first beat signal. It is not limited to a photodiode as long as a signal including the first signal can be output. For example, the first detection unit 40 may output a signal including the first beat signal by measuring the voltage fluctuation of the first semiconductor laser 12. The same applies to the second detection unit 50. The same applies to the third detection unit 440 and the fourth detection unit 450 (see FIG. 14) in the fourth embodiment described above.

  Further, the above-described embodiments and modifications are examples, and the present invention is not limited to these. For example, each embodiment and each modification can be combined as appropriate.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 2 ... Condensing lens, 4 ... Element separation part, 12 ... 1st semiconductor laser, 22 ... 2nd semiconductor laser, 30 ... Beam splitter, 40 ... 1st detection part, 42 ... 1st photodiode, 50 ... 2nd detection , 52 ... second photodiode, 60 ... first drive unit, 70 ... second drive unit, 80 ... calculation unit, 82a ... current-voltage conversion circuit, 82b ... current-voltage conversion circuit, 82c ... current-voltage conversion circuit, 82d ... Current-voltage conversion circuit, 84a ... Filter circuit, 84b ... Filter circuit, 84c ... Filter circuit, 84d ... Filter circuit, 86a ... Counting circuit, 86b ... Counting circuit, 86c ... Counting circuit, 86d ... Counting circuit, 88 ... Calculation device DESCRIPTION OF SYMBOLS 100 ... Measuring device 101 ... Substrate 102 ... First mirror layer 103 ... Active layer 104 ... Second mirror layer 105 ... Current confinement layer 106 ... Contour Layer, 107 ... insulating layer, 108 ... first electrode, 109 ... second electrode, 110 ... first contact layer, 112 ... light absorbing layer, 114 ... second contact layer, 115 ... insulating layer, 116 ... third electrode 118 ... 4th electrode, 200 ... measuring device, 202 ... current-voltage conversion circuit, 204 ... FFT circuit, 206 ... arithmetic unit, 210 ... photodiode, 300 ... measuring device, 400 ... measuring device, 405 ... measuring device, 412 ... third semiconductor laser, 422 ... fourth semiconductor laser, 440 ... third detection unit, 442 ... third photodiode, 450 ... fourth detection unit, 452 ... fourth photodiode, 460 ... third drive unit, 470 ... Fourth drive unit, 500 ... printer, 502 ... moving member, 503 ... moving mechanism, 504 ... transport mechanism, 520 ... head unit, 524 ... carriage, 531 ... ,... Carriage guide shaft, 533... Timing belt, 540... Platen, 541... Transport motor, 542. , 612 ... Robot arm, 614 ... Force detector, 616 ... Dispenser, 620 ... Movable part, 680 ... Object, 690 ... Discharge, 1000 ... Electronic equipment, 1020 ... Arithmetic processing unit, 1030 ... Operation part, 1040 ... ROM 1050 ... RAM, 1060 ... communication unit, 1070 ... display unit, 1100 ... moving body, 1120 ... controller, 1130 ... controller, 1140 ... controller, 1150 ... battery, 1160 ... battery for backup

Claims (12)

A first semiconductor laser that emits a first laser beam irradiated to a measurement object;
A second semiconductor laser that emits a second laser beam applied to the measurement object;
The first semiconductor laser is operated such that a period in which the wavelength of the first laser light continuously increases monotonously and a period in which the wavelength of the first laser light continuously decreases monotonously exists. One drive unit;
A second driving unit that operates the second semiconductor laser such that the phase of fluctuation of the wavelength of the second laser light and the phase of fluctuation of the wavelength of the first laser light are opposite to each other;
A first beat signal corresponding to interference light generated by a self-coupling effect caused by the first laser light emitted from the first semiconductor laser and the return light of the first laser light from the measurement target; A first detector for outputting a signal;
A second beat signal corresponding to interference light generated by a self-coupling effect caused by the second laser light emitted from the second semiconductor laser and the return light of the second laser light from the measurement target; A second detector for outputting a signal;
A calculation unit that obtains at least one of a distance to the measurement object and a speed of the measurement object based on the first signal and the second signal;
Including
The measuring device, wherein the first semiconductor laser and the second semiconductor laser are provided on the same substrate. In claim 1,
The first detection unit includes a first photodiode,
The second detection unit includes a second photodiode,
The measuring device, wherein the first semiconductor laser, the second semiconductor laser, the first photodiode, and the second photodiode are provided on the same substrate. In claim 1,
The first detection unit and the second detection unit have a common photodiode,
The measuring device, wherein the first semiconductor laser, the second semiconductor laser, and the common photodiode are provided on the same substrate. In any one of Claims 1 thru | or 3,
A measuring apparatus including a condenser lens on which the first laser light and the second laser light are incident. In claim 4,
A distance between the first semiconductor laser and the measurement object along the chief ray of the first laser light; and the second semiconductor laser and the measurement object along the chief ray of the second laser light. The distance between is equal to the measuring device. In claim 4,
A distance between the first semiconductor laser and the measurement object along the chief ray of the first laser light; and the second semiconductor laser and the measurement object along the chief ray of the second laser light. The measuring device is different from the distance between. In any one of Claims 4 thru | or 6,
It straddles the optical path of the first laser light between the first semiconductor laser and the condenser lens and the optical path of the second laser light between the second semiconductor laser and the condenser lens. Including a beam splitter arranged to
The beam splitter reflects a part of the first laser beam emitted from the first semiconductor laser toward the first detection unit, and outputs a part of the second laser beam emitted from the second semiconductor laser. A measurement device that reflects a part toward the second detection unit. In any one of Claims 1 thru | or 3,
A first condenser lens on which the first laser beam emitted from the first semiconductor laser is incident;
A second condenser lens on which the second laser light emitted from the second semiconductor laser is incident;
Including a measuring device. In claim 8,
On the optical path of the first laser light between the first semiconductor laser and the first condensing lens, and on the optical path of the second laser light between the second semiconductor laser and the second condensing lens And a beam splitter arranged to straddle,
The beam splitter reflects a part of the first laser beam emitted from the first semiconductor laser toward the first detection unit, and outputs a part of the second laser beam emitted from the second semiconductor laser. A measurement device that reflects a part toward the second detection unit. In any one of Claims 1 thru | or 9,
The measuring device, wherein the first semiconductor laser and the second semiconductor laser are surface emitting lasers.   A printer comprising the measurement device according to claim 1.   An electronic device comprising the measuring device according to claim 1.

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