Distance measuring device using frequency-disturbed pulse

Abstract

A distance measuring device according to the present embodiment may comprise: a control unit; a current supply unit; a light source unit; a light distribution unit; a light targeting unit; and a light processing unit and may measure a distance by using a frequency-disturbed pulse. Lights of different frequencies may be generated by supplying a reference current and a pulse current to a light source according to a signal of the control unit of an embodiment. The generated lights may be distributed and emitted to a target, and the light processing unit may receive the reflection light and convert the reflection light into an electrical signal. The control unit may derive the distance between the light targeting unit and the target through a time difference between the alternating current components adjacent to each other.

Description

Distance measuring device using frequency-disturbed pulses

[0001] The present invention relates to a distance measuring device using frequency-disturbed pulses.

[0002] Conventional Time of Flight (ToF) distance measuring devices can determine the distance to a target based on the time difference between the light emitted toward the target and the light reflected from the target. However, because the intensity of the light reflected from the target is very small compared to the intensity of the light emitted toward the target, the accuracy of distance measurement is reduced, or it is difficult to measure the distance to a distant target.

[0003] In addition, a general FMCW (Frequency Modulated Continuous Wave) distance measuring device can measure the distance between a target and a LiDAR (Light Detection And Ranging) by mixing the frequency of light irradiated toward the target and the frequency of light reflected from the target to measure the beat frequency. In this case, the light irradiated toward the target in a general FMCW distance measuring device may have a sawtooth pattern frequency that gradually increases over time.

[0004] In general FMCW-type distance measuring devices, if the maximum value of the sawtooth pattern frequency is set too high, the photodetector or photoamplifier may have difficulty operating normally.

[0005] In addition, conventional FMCW-type distance measuring devices may experience reduced accuracy in distance measurement because they are sensitive to changes in optical frequency depending on the surrounding environment of the light source.

[0006] In addition, since conventional FMCW distance measuring devices must use very expensive high-speed Fourier transforms, the price of the distance measuring device may increase.

[0007] Regarding background technology, there is Korean registered patent KR10-2097247-0000.

[0008] The distance derivation device using frequency-disturbed pulses according to an embodiment of the present invention is intended to improve upon the problems of ToF-type distance measuring devices and FMCW-type distance measuring devices.

[0009] The problems of this application are not limited to those mentioned above, and other problems not mentioned will be clearly understood by a person skilled in the art from the description below.

[0010] A distance measuring device using frequency-disturbed pulses according to one aspect of the present invention comprises a control unit, a current supply unit, a light source unit, a light distribution unit, a light targeting unit, and a light processing unit. The current supply unit supplies a reference current and a pulse current greater than the reference current to the light source unit over time according to a control signal of the control unit. The light source unit outputs a measurement light composed of a light of a first frequency output according to the supply of the reference current and a light of a second frequency different from the first frequency output according to the supply of the pulse current. The light distribution unit distributes the measurement light into a first distributed light and a second distributed light. The light targeting unit receives the first distributed light and outputs a target light toward a target, collects reflected light reflected from the target, and outputs a received light. The light processing unit processes the second distributed light and the received light to output an electrical signal in which a DC component and an AC component flow over time. The AC component of the electrical signal is a third frequency corresponding to the difference between the first frequency and the second frequency. The control unit has the above-mentioned distance between the light targeting unit and the target through the time difference between the adjacent alternating current components.

[0011] The current supply unit includes a first current source, a second current source, a pulse generator, and a switching unit, wherein the first current source supplies the reference current to the light source unit according to a control signal of the control unit, the second current source outputs the modulation current according to a control signal of the control unit, the pulse generator applies the pulse signal to the switching unit according to a control signal of the control unit, and the switching unit switches according to the pulse signal to supply the modulation current, and the reference current and the modulation current can be combined to form the pulse current.

[0012] The above light processing unit includes an optical coupling unit and a light detection unit, wherein the optical coupling unit combines the input second distributed light and the received light and divides the intensity of the combined light according to a set ratio to output it, and the light detection unit processes the combined light output from the optical coupling unit to output the electrical signal.

[0013] The above photodetector includes a first photodiode and a second photodiode, and the anode terminal of the first photodiode, the cathode terminal of the second photodiode, and the output terminal of the photodetector are electrically connected so that the electrical signal is output through the output terminal of the photodetector, and the first photodiode is irradiated with combined light output from one output terminal of the optical coupling unit, and the second photodiode can be irradiated with combined light output from another output terminal of the optical coupling unit.

[0014] The above-described photodetector includes a photodiode, a DC component detector, and an AC component detector, and the anode end of the photodiode, one end of the DC component detector, and one end of the AC component detector are electrically connected to each other so that the electrical signal is output through the other end of the AC component detector, and the photodiode may be irradiated with coupled light output from one output end of the optical coupling unit.

[0015] The above DC component detection unit includes an inductor, and the above AC component detection unit includes a capacitor; the anode terminal of the photodiode, one end of the inductor, and one end of the capacitor are electrically connected to each other so that the electrical signal is output through the other end of the capacitor, and the other end of the inductor may be grounded.

[0016] The control unit includes a signal amplifier, an envelope detector, a decision circuit, and a controller. The signal amplifier amplifies the electrical signal of the optical processing unit, the envelope detector detects the envelope of the AC component of the amplified electrical signal, the decision circuit derives a pulse wave by synchronizing the detected envelope with a reference clock, and the controller can derive the distance of the target through the time difference between adjacent pulse waves corresponding to the time difference.

[0017] The control unit may include a signal amplifier that amplifies the electrical signal of the optical processing unit, a bandpass filter that performs bandpass filtering on the amplified electrical signal and outputs the AC component, a frequency counter that counts the frequency of the AC component output from the bandpass filter module, a comparator that compares the frequency output from the frequency counter with a reference frequency and outputs an error between the frequency output from the frequency counter and the reference frequency, and a controller that outputs the reference frequency and outputs a control signal to the second current source to control the current magnitude according to the error.

[0018] A distance measuring device using a frequency-disturbed pulse according to one aspect of the present invention further includes an optical delay line that delays the propagation of the first distributed light output from the optical distribution unit by a delay time, and the delay time may be greater than the time width of the pulse of the first distributed light having the second frequency.

[0019] The above light targeting unit includes a light circulator and a target unit, and the light circulator receives a first distributed light through an input port and outputs it to the target unit through a common port, and receives reflected light incident through the target unit from the common port and outputs it to a light processing unit through an output port.

[0020] In addition to the method using the above-mentioned optical circulator, the optical targeting unit can be configured in various forms, such as physically separating transmission and reception or adjusting polarization.

[0021] A distance measuring device using frequency-disturbed pulses according to an embodiment of the present invention can improve the problems of ToF-type distance measuring devices and FMCW-type distance measuring devices by modulating the frequency of light according to pulses generated through changes in the magnitude of the current of a semiconductor laser.

[0022] The effects of the present application are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description below.

[0023] FIG. 1 shows a distance measuring device using frequency-disturbed pulses according to an embodiment of the present invention.

[0024] Figure 2 shows various waveform changes of a distance measuring device using frequency-disturbed pulses according to an embodiment of the present invention.

[0025] Figure 3 shows the change in frequency according to the temperature and current magnitude of the semiconductor laser.

[0026] Figures 4 and 5 show examples of the configuration of the light processing unit.

[0027] Figure 6 shows the signal processing process of the control unit.

[0028] Figure 7 shows an example of the internal configuration of the control unit.

[0029] Figures 8 and 9 are drawings for explaining optical delay lines.

[0030] Figure 10 shows another example of the configuration of the optical targeting unit.

[0031] The best mode for carrying out the invention is described together with the modes for carrying out below.

[0032] Embodiments of the present invention will be described in detail below with reference to the attached drawings. However, it will be readily apparent to those skilled in the art that the attached drawings are provided merely to facilitate the disclosure of the content of the present invention, and that the scope of the present invention is not limited to the scope of the attached drawings.

[0033] Furthermore, the terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0034] In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0035] FIG. 1 shows a distance measuring device using frequency-disturbed pulses according to an embodiment of the present invention. As shown in FIG. 1, the distance measuring device using frequency-disturbed pulses according to an embodiment of the present invention (hereinafter, distance measuring device) includes a control unit (110), a current supply unit (130), a light source unit (150), a light distribution unit (170), a light targeting unit (190), and a light processing unit (210).

[0036] As illustrated in FIG. 2 (a), the current supply unit (130) supplies a reference current and a pulse current greater than the reference current to the light source unit (150) over time according to the control signal of the control unit (110).

[0037] The light source unit (150) outputs measurement light. It consists of light of a first frequency output according to the supply of a reference current and light of a second frequency different from the first frequency output according to the supply of a pulse current.

[0038] The light source unit (150) may include a laser diode. The cathode end of the laser diode may be electrically connected to a first current source (131) to be described later, and the anode end of the laser diode may be electrically connected to a power source.

[0039] The light distribution unit (170) distributes the measurement light into a first distribution light and a second distribution light.

[0040] The light distribution unit (170) distributes the measurement light incident from the light source unit (150) to output a first distributed light and a second distributed light, and the intensity of the first distributed light may be greater than the intensity of the second distributed light. The first distributed light is irradiated onto a target through the light targeting unit (190), which will be described later, and at this time, since the intensity of the reflected light reflected from the target is reduced, the intensity of the first distributed light may be greater than the intensity of the second distributed light.

[0041] The light distribution unit (170) can be connected to an optical fiber through which the measurement light emitted from the light source unit (150) passes. The light distribution unit (170) can be connected to the light targeting unit (190) and the light processing unit (210) via an optical fiber.

[0042] The light targeting unit (190) receives the first distributed light and outputs the target light toward the target, and collects the reflected light reflected from the target and outputs the received light.

[0043] The optical targeting unit (190) may include an optical transmission unit (195) and an optical collecting unit (197). The optical transmission unit (195) may irradiate target light toward a target by having a first distributed light incident thereon, and the optical collecting unit (197) may collect reflected light reflected from the target. The optical transmission unit (195) and the optical collecting unit (197) may be equipped with lenses, etc., for transmitting target light and collecting reflected light. Received light may pass through an optical fiber connected to the optical collecting unit (197) and the optical processing unit (210).

[0044] Although not illustrated in FIG. 1, an optical amplification unit may be additionally provided between the optical distribution unit (170) and the optical targeting unit (190). The optical amplification unit can amplify the first distributed light and output it to the optical targeting unit (190). As the intensity of the target light and reflected light increases with the amplification of the first distributed light, the optical processing unit (210) can process the received light relatively easily.

[0045] As illustrated in Figures 2 (b) and (c), the light processing unit (210) processes the second distributed light and the received light to output an electrical signal in which a direct current component and an alternating current component flow over time, and the alternating current component of the electrical signal has a third frequency corresponding to the difference between the first frequency and the second frequency.

[0046] The control unit (110) derives the distance between the light targeting unit (190) and the target through the time difference (Td) between adjacent alternating current components. That is, the time difference (Td) is 2R / c, since it is the time it takes for light to travel back and forth to the target. At this time, R is the distance to the target, and c may correspond to the speed of light.

[0047] As described above, the distance measuring device according to the embodiment of the present invention derives the distance to a target through the time difference (Td) of adjacent alternating current components, so it may not include a fast Fourier transform.

[0048] The distance measuring device according to an embodiment of the present invention can be configured more simply because it modulates the frequency through a change in the magnitude of the current, rather than using a frequency that increases in a sawtooth pattern like a general FMCW distance measuring device.

[0049] The distance measuring device according to an embodiment of the present invention uses an alternating current component of a third frequency corresponding to the difference between a first frequency and a second frequency, so it can be relatively less affected by the intensity of reflected light.

[0050] As illustrated in FIG. 1, the current supply unit (130) may include a first current source (131), a second current source (133), a pulse generator (135), and a switching unit (137).

[0051] As illustrated in FIG. 2 (a), the first current source (131) can supply a reference current to the light source unit (150) according to a control signal from the control unit (110). One end of the first current source (131) can be electrically connected to the light source unit (150), and the other end of the first current source (131) can be electrically connected to the control unit (110). At this time, the control unit (110) can control the amount of current by providing a control signal to the other end of the first current source (131) to regulate the amount of current of the first current source (131).

[0052] The second current source (133) can output a modulated current according to a control signal from the control unit (110). One end of the second current source (133) is electrically connected to the switching unit (137), and the other end of the second current source (133) can be electrically connected to the control unit (110).

[0053] The first current source (131) and the second current source (133) may be direct current sources, and accordingly, the reference current and the modulation current may be direct currents.

[0054] The pulse generator (135) can apply a pulse signal to the switching unit (137) according to a control signal from the control unit (110). One end of the pulse generator (135) can be electrically connected to the switching unit (137), and the other end of the pulse generator (135) can be electrically connected to the control unit (110).

[0055] The switching unit (137) can supply a modulated current by switching according to a pulse signal. One end of the switching unit (137) is electrically connected to the second current source (133), the other end of the switching unit (137) is electrically connected to the pulse generator (135), and yet another end of the switching unit (137) can be electrically connected to the light source unit (150).

[0056] During the time that the pulse signal provided by the pulse generator (135) is maintained, the reference current and the modulation current are combined according to the supply of the modulation current to form a pulse current, and the pulse current can be applied to the light source (150).

[0057] Accordingly, as shown in FIG. 2 (a), while a pulse signal is applied to the switching unit (137), a pulse current in which the reference current and the modulation current are combined can be supplied to the light source unit (150).

[0058] In FIG. 1, the pulse generator (135) is shown as a separate block distinct from the control unit (110), but it may be integrated into the control unit (110).

[0059] As shown in FIG. 3, the frequency of light emitted from the laser diode of the light source (150) can be increased in proportion to the magnitude of the current applied to the laser diode.

[0060] In the distance measuring device of the present invention, the magnitude of the current applied to the light source unit (150) in the pulse section of FIG. 2 is increased, so that the frequency of light in the pulse section can be greater than the frequency of light in the non-pulse section.

[0061] As such, the distance measuring device according to the embodiment of the present invention can measure distance by modulating the frequency of light through a change in the magnitude of the direct current applied to the light source unit (150). Accordingly, the distance measuring device according to the embodiment of the present invention may not use a frequency that changes according to the sawtooth pattern used in the general FMCW method.

[0062] As illustrated in FIG. 1, the light processing unit (210) may include a light coupling unit (211) and a light detection unit (213).

[0063] The optical coupling unit (211) can combine the second distributed light received from the light distribution unit (170) and the received light incident from the light targeting unit (190), and output the intensity of the combined light divided according to a set ratio. The optical coupling unit (211) may be a 2x2 coupler, and the set ratio may be 5:5, but the present invention is not limited thereto.

[0064] The photodetector (213) can process the combined light output from the photocoupler (211) to output an electrical signal. At this time, the electrical signal may consist of a direct current component and an alternating current component that flow over time, such as a waveform as shown in (c) of FIG. 2.

[0065] At this time, the DC component is formed when the frequencies of the second distributed light and the received light are the same, and the AC component can be formed when the frequencies of the second distributed light and the received light are different from each other.

[0066] Since the received light is reflected from the target, the pulse interval of the received light may be delayed by Td from the pulse interval of the second distributed light. The distance measuring device of the present invention can derive the distance to the target through Td.

[0067] As such, the distance measuring device of the present invention derives Td through the difference in frequency, thereby resolving the difficulty of distance measurement caused by the decrease in the intensity of light reflected from the target in the general ToF method.

[0068] As illustrated in FIG. 1, the photodetector (213) may include a first photodiode (PD1) and a second photodiode (PD2).

[0069] The anode terminal of the first photodiode (PD1), the cathode terminal of the second photodiode (PD2), and the output terminal of the photodetector (213) are electrically connected so that an electrical signal can be output through the output terminal of the photodetector (213).

[0070] Additionally, the first photodiode (PD1) may be irradiated with combined light output from one output terminal of the optical coupling unit (211), and the second photodiode (PD2) may be irradiated with combined light output from another output terminal of the optical coupling unit (211).

[0071] 2P in Fig. 4 R and 2P LO P1 and P2 may correspond to the power of the reflected light and the power of the second distributed light, respectively, input to the optical coupling unit (211). P1 and P2 are the output power of the optical coupling unit (211), respectively.

[0072] If the light distribution ratio in the optical coupler is 50:50, then P1 and P2 are equal to the following mathematical formulas 1 and 2.

[0073] [Mathematical Formula 1]

[0074]

[0075]

[0076] [Mathematical Formula 2]

[0077]

[0078] Here f R - f LO is the difference between the first frequency and the second frequency, i.e., the third frequency f b It may correspond to. Also, (φ R - φ LO ) is the phase difference.

[0079] When the power of the reflected light is very small compared to the power of the second distributed light and the phase difference is ignored, Equations 1 and 2 are approximately equal to the following Equations 3 and 4.

[0080] [Mathematical Formula 3]

[0081]

[0082]

[0083] [Mathematical Formula 4]

[0084]

[0085]

[0086] When light corresponding to P1 and P2 is supplied to the first photodiode (PD1) and the second photodiode (PD2), the currents I1 and I2 flowing through the first photodiode (PD1) and the second photodiode (PD2) are given by the following mathematical formulas 5 and 6.

[0087] [Mathematical Formula 5]

[0088]

[0089]

[0090] [Mathematical Formula 6]

[0091]

[0092]

[0093] In mathematical formulas 5 and 6, R1 and R2 are conversion factors for converting power into current.

[0094] Accordingly, the output current I of the photodetector (213) TIA It is equal to the following mathematical formula 7.

[0095] [Mathematical Formula 7]

[0096]

[0097] Since the optical coupler outputs the combined light intensity by dividing it into 50:50, the conversion factors R1 and R2 have the same value, and accordingly, the output current of the photodetector (213) is as shown in the following mathematical formula 8.

[0098] [Mathematical Formula 8]

[0099]

[0100]

[0101] As can be seen from mathematical equation 8, the output current of the photodetector (213), that is, the electrical signal output by the photoprocessing unit (210), is the difference (f) between the first frequency and the second frequency. b It can be seen that it changes according to the third frequency.

[0102] Accordingly, as illustrated in Figures 2 (b) and (c), the area of ​​the overlap between the second distributed light and the received light that overlaps at the first frequency becomes a DC component because there is no difference in frequency, and the area of ​​the overlap between the first frequency and the second frequency becomes an AC component because there is a difference in frequency.

[0103] The photodetector (213) may have a different configuration from that of FIG. 1 and FIG. 4. That is, as shown in FIG. 5, the photodetector (213) may include a photodiode (PD), a DC component detector (2131), and an AC component detector (2133).

[0104] The anode end of the photodiode (PD), one end of the DC component detection unit (2131), and one end of the AC component detection unit (2133) are electrically connected to each other so that an electrical signal can be output through the other end of the AC component detection unit (2133).

[0105] The photodiode (PD) can be irradiated with combined light output from one output terminal of the optical coupling unit (211).

[0106] The power of light irradiated onto a single photodiode is of Equation 3 explained earlier is. Mathematical Equation 3 is P LO a direct current component called and It can be composed of alternating current components.

[0107] The DC component detection unit (2131) can detect the DC component of Equation 3 and send it to ground. The AC component detection unit (2133) can detect the AC component of Equation 3. I of FIG. 5 AC Is , and this is the I explained earlier TIA It may correspond to. Here, R is a conversion factor for converting optical power into current in a photodiode.

[0108] In FIG. 5, a 2x2 optical coupling unit (211) is shown, and in this case, the coupling light output from the other output terminal of the optical coupling unit (211) can be blocked. Also, a 2x1 optical coupling unit (211) may be used instead of the 2x2 optical coupling unit (211).

[0109] The DC component detection unit (2131) includes an inductor, and the AC component detection unit (2133) may include a capacitor. The anode terminal of the photodiode (PD), one end of the inductor, and one end of the capacitor are electrically connected to each other so that an electrical signal is output through the other end of the capacitor, and the other end of the inductor may be grounded.

[0110] In the case of capacitors, AC components can be detected because their impedance for AC components is smaller than their impedance for DC components. Additionally, in the case of inductors, DC components can be detected because their impedance for DC components is smaller than their impedance for AC components.

[0111]

[0112] As illustrated in FIG. 7, the control unit (110) may include a signal amplifier (111), an envelope detector (113), and a decision circuit unit (114). For convenience of illustration, FIG. 8 illustrates a partial configuration of a distance measuring device according to an embodiment of the present invention.

[0113] As illustrated in FIG. 6 (a) and (b), the signal amplifier (111) amplifies the electrical signal of the optical processing unit, and the envelope detector (113) can detect the envelope of the AC component of the amplified electrical signal. The decision circuit unit (114) can derive a pulse wave by synchronizing the envelope with the clock. The reference clock can be input from the controller (121) to the decision circuit unit (114).

[0114] The controller (121) can derive the distance of the target through the time difference between adjacent pearl spas corresponding to the previously described time difference (Td).

[0115] The signal amplifier (111) may include a preamplifier module and a limiting amplifier module. The limiting amplifier module can amplify the voltage to a digital voltage level.

[0116] The control unit (110) can perform synchronization of the reference clock and the pulse wave using a D-flip-flop and derive the time difference (Td) by counting the number of reference clocks between adjacent pulse waves.

[0117] As illustrated in FIG. 7, the control unit (110) may include a signal amplifier (111), a bandpass filter (115), a frequency counter (117), a comparator (119), and a controller (121).

[0118] The signal amplifier (111) can amplify the electrical signal of the light processing unit.

[0119] As illustrated in (e) of FIG. 2, the bandpass filter (115) can output an alternating current component by performing bandpass filtering on the amplified electrical signal. That is, the bandpass filter (115) can receive the amplified electrical signal and pass a third frequency band, which is the difference between the first frequency and the second frequency.

[0120] The frequency counter (117) can count the frequency of the alternating current component output from the bandpass filter (115).

[0121] The comparator (119) can compare the frequency output from the frequency counter (117) with the reference frequency and output the difference between the frequency output from the frequency counter (117) and the reference frequency.

[0122] The controller (121) outputs a reference frequency and can output a control signal to the second current source (133) to control the current magnitude according to the difference. Accordingly, the third frequency can be maintained constant by changing the magnitude of the second current to correct the difference.

[0123] As illustrated in FIGS. 8 and 9, a distance measuring device according to an embodiment of the present invention delays the progression of a first distributed light output from a light distribution unit (170) by a delay time (t D It may further include an optical delay line (230) that delays by ) amount. FIG. 8 shows only a part of a distance measuring device according to an embodiment of the present invention for the convenience of illustration.

[0124]

[0125] The optical delay line (230) may include a rolled optical fiber, and the first distributed light may be delayed by the time it passes through the optical delay line (230).

[0126] The use of such an optical delay line (230) is intended to prevent the pulse of the second distributed light and the pulse of the received light from overlapping at least partially. That is, when the optical targeting unit (190) and the target are excessively close, the pulse of the second distributed light output from the optical distribution unit (170) and the pulse of the received light through the optical targeting unit (190) may overlap, as shown in the upper part of FIG. 9.

[0127] In this way, if the pulses overlap even partially, the distance measurement to the target may not be accurate. The optical delay line (230) has a delay time (t D By delaying the propagation of light by ) amount, the superposition of pulses can be prevented.

[0128] At this time, as shown in the lower part of FIG. 9, the delay time (t D ) is the time width (t) of the pulse of the first divided light having the second frequency. pulse It can be greater than ). Unlike the present invention, as illustrated in the middle of FIG. 9, the delay time (t D ) is the above time width (t pulse If it is smaller than ), the overlap between pulses may not be resolved due to the time delay.

[0129] Accordingly, the control unit (110) has a time difference (t) between adjacent pulses. pulse +t D After deriving the distance through ), the delay time (t) from the derived result D The distance to the target can be derived by subtracting the distance based on ).

[0130]

[0131] FIG. 10 shows another example of the configuration of the light targeting unit (190). FIG. 10 shows only a part of the configuration of the distance measuring device according to an embodiment of the present invention for the convenience of illustration.

[0132] The light targeting unit (190) may include a light circulator (191) and a target unit (193). The light circulator (191) receives a first distributed light through an input port and outputs it to the target unit (193) through a common port, and receives reflected light received through the target unit (193) from the common port and outputs it to the light processing unit (210) through an output port.

[0133] Accordingly, the structure of the light targeting unit (190) shown in Fig. 1 can be simplified.

[0134] As described above, embodiments according to the present invention have been examined. It is obvious to those skilled in the art that, in addition to the embodiments described above, the present invention may be embodied in other specific forms without departing from its spirit or scope. Therefore, the embodiments described above should be regarded as illustrative rather than restrictive, and accordingly, the present invention is not limited to the description above but may be modified within the scope of the appended claims and their equivalents.

[0135] The above embodiment is industrially available as it is possible to repeat the implementation.

Claims

1. It includes a control unit, a current supply unit, a light source unit, a light distribution unit, a light targeting unit, and a light processing unit, The current supply unit supplies a reference current and a pulse current greater than the reference current to the light source unit over time according to a control signal of the control unit, and The light source unit outputs a measurement light composed of light of a first frequency output according to the supply of the reference current and light of a second frequency different from the first frequency output according to the supply of the pulse current, and The light distribution unit above distributes the measurement light into a first distributed light and a second distributed light, and The above light targeting unit receives a first distributed light and outputs a target light toward a target, collects reflected light reflected from the target and outputs a received light, and The light processing unit processes the second distributed light and the received light to output an electrical signal in which a direct current component and an alternating current component flow over time, and the alternating current component of the electrical signal has a third frequency corresponding to the difference between the first frequency and the second frequency. A distance measuring device using frequency-disturbed pulses, characterized in that the control unit derives the distance between the optical targeting unit and the target through the time difference between adjacent alternating current components.

2. In Paragraph 1, The above current supply unit includes a first current source, a second current source, a pulse generator, and a switching unit, and The first current source supplies the reference current to the light source according to the control signal of the control unit, and The second current source outputs the modulation current according to the control signal of the control unit, and the pulse generator applies the pulse signal to the switching unit according to the control signal of the control unit. The above switching unit switches according to the pulse signal to supply the modulation current, and A distance measuring device using a frequency-disturbed pulse, characterized in that the above reference current and the above modulation current are combined to form the above pulse current.

3. In Paragraph 1 or 2, The above-mentioned light processing unit includes a light coupling unit and a light detection unit, and The above optical coupling unit combines the input second distributed light and the received light, divides the intensity of the combined light according to a set ratio, and outputs it. A distance measuring device using frequency-disturbed pulses, characterized in that the above-mentioned photodetector processes the combined light output from the above-mentioned photocoupler and outputs the above-mentioned electrical signal.

4. In Paragraph 3, The above photodetector includes a first photodiode and a second photodiode, and The anode terminal of the first photodiode, the cathode terminal of the second photodiode, and the output terminal of the photodetector are electrically connected so that the electrical signal is output through the output terminal of the photodetector. The first photodiode is irradiated with combined light output from one output terminal of the optical coupling unit, and A distance measuring device using frequency-disturbed pulses, characterized in that the second photodiode is irradiated with combined light output from another output terminal of the optical coupling unit.

5. In Paragraph 3, The above photodetector includes a photodiode, a DC component detector, and an AC component detector, and The anode terminal of the photodiode, one end of the DC component detector, and one end of the AC component detector are electrically connected to each other, and the electrical signal is output through the other end of the AC component detector. A distance measuring device using frequency-disturbed pulses, characterized in that the photodiode is irradiated with combined light output from one output terminal of the optical coupling unit.

6. In Paragraph 5, The above DC component detector includes an inductor, and the above AC component detector includes a capacitor, The anode terminal of the photodiode, one end of the inductor, and one end of the capacitor are electrically connected to each other, and the electrical signal is output through the other end of the capacitor. A distance measuring device using frequency-disturbed pulses, characterized in that the other end of the above-mentioned inductor is grounded.

7. In Paragraph 1, The above control unit includes a signal amplifier, an envelope detector, a decision circuit, and a controller, and The above signal amplifier amplifies the electrical signal of the above light processing unit, and the above envelope detector detects the envelope of the alternating current component of the amplified electrical signal, and The above decision circuit unit derives a pulse wave by synchronizing the detected envelope with a reference clock, and A distance measuring device using frequency-disturbed pulses, characterized in that the controller derives the distance of the target through the time difference between adjacent pulse waves corresponding to the time difference.

8. In Paragraph 2, The above control unit The signal amplifier that amplifies the electrical signal of the above-mentioned light processing unit, A bandpass filter that outputs the AC component by performing bandpass filtering on the amplified electrical signal, A frequency counter for counting the frequency of the AC component output from the bandpass filter module above, A comparator that compares the frequency output from the frequency counter with the reference frequency and outputs the difference between the frequency output from the frequency counter and the reference frequency, A controller that outputs the above reference frequency and outputs a control signal to the second current source for controlling the current magnitude according to the above difference. A distance measuring device using frequency-disturbed pulses characterized by including 9. In Paragraph 1, It further includes an optical delay line that delays the propagation of the first distributed light output from the above-mentioned optical distribution unit by a delay time, and A distance measuring device using a frequency-disturbed pulse, characterized in that the above delay time is greater than the time width of the pulse of the first distributed light having the second frequency.

10. In Paragraph 1, The above light targeting unit includes a light circulator and a target unit, and The above light circulator is The first distributed light is received through the input port and output to the target unit through the common port, and A distance measuring device using frequency-disturbed pulses, characterized by receiving reflected light incident through the target section from the common port and outputting it to the light processing section through the output port.

11. In Paragraph 1, The first distributed light is amplified in the light amplification unit located between the light distribution unit and the light targeting unit and output to the light targeting unit, A distance measuring device using frequency-disturbed pulses characterized by increasing the intensity of target light and reflected light so that the light processing unit can process the received light relatively easily.

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