KR102627699B1 - Light detection and ranging system - Google Patents

Abstract

The present invention includes a laser transmitter; a first laser receiver; It includes a second laser receiver, and the laser transmitter includes first to Nth laser diodes that generate pulsed lasers, and the first laser receiver and the second laser receiver each receive an angle of incidence of the reflected beam. first to M photodiodes that detect whether light is received and generate a light reception signal; first to L multiplexers that select and connect one of the first to M photodiodes according to a selection signal; (L = M/N) A LIDAR system is provided, including first to L comparators that generate a low-voltage differential signal with a logic level in response to the light-receiving signal.

Description

LIDAR SYSTEM { LIGHT DETECTION AND RANGING SYSTEM }

The present invention relates to a LiDAR system that detects objects through one or more channels.

LiDAR (Light Detection And Ranging, LiDAR) irradiates a laser beam to a target and then collects the distance to the target, the direction in which the target is located, the speed at which the target moves, the temperature of the target, material distribution, concentration characteristics, and 3D image information. It is a technique that does.

Lidar can be used in various fields such as atmospheric analysis, global environmental observation, urban topographical information analysis, and autonomous driving of cars.

Lidar can be classified into ToF (Time of Flight) and PS (Phase Shift) methods depending on the modulation method of the laser signal. In the ToF method, a laser transmitter emits a pulse signal and then measures the time it takes for it to be reflected from objects within the measurement range and return to the laser receiver, thereby obtaining distance information between the lidar and the objects. The PS method emits a frequency modulated continuous wave and then measures the phase change of the signal reflected from objects within the measurement range and returned to the laser receiver, providing distance information between the lidar and the objects. It is to acquire.

For lidar with these characteristics, there is a need to improve measurement precision and accuracy.

The purpose of the present invention is to provide a multi-channel LIDAR system with improved measurement precision and accuracy.

In order to achieve the above object, the present invention includes a laser transmitter; a first laser receiver; It includes a second laser receiver, and the laser transmitter includes first to Nth laser diodes that generate pulsed lasers, and the first laser receiver and the second laser receiver each receive an angle of incidence of the reflected beam. first to M photodiodes that detect whether light is received and generate a light reception signal; first to L multiplexers that select and connect one of the first to M photodiodes according to a selection signal; (L = M/N) A LIDAR system is provided, including first to L comparators that generate a low-voltage differential signal with a logic level in response to the light-receiving signal.

And, it further includes a control unit, wherein the control unit transmits first to Nth trigger signals to the laser transmitter, and the first to Nth laser diodes respectively correspond to the first to Nth trigger signals, A LIDAR system that generates first to Nth pulse lasers is provided.

In addition, the first to M photodiodes generate first to M light-receiving signals with a first voltage when the reflected beam is received, and a first to M photodiodes with a second voltage when the reflected beam is not received. A LiDAR system is provided that generates 1st to Mth light reception signals.

Then, the control unit initializes the value (k) of the selection signal to 0, then increases the value (k) of the selection signal by 1 at each selection interval, and the increased value (k) of the selection signal is N. If , it is initialized to 0, and the kL+1th to (k+1)th photodiodes are respectively connected to the first to Lth multiplexers, and the first to Lth multiplexers are respectively, A LIDAR system is provided that outputs the kL+1 to (k+1)th light reception signals.

And, when the kL+1 to (k+1)Lth light-receiving signals have the first voltage, the first to Lth comparators respectively have a logic high level. Generate low-voltage differential signals, and when the kL+1 to (k+1)Lth light-receiving signals have the second voltage, generate the first to Lth low-voltage differential signals having a logic low level. Provides a lidar system that generates

And, the control unit calculates the difference between the time of generating the i-th trigger signal and the time of receiving each of the first to L-th low voltage differential signals as (i-1)L+1 to iL-th arrival times. Provides a LiDAR system that calculates (1≤i≤N, i is a natural number).

And, it further includes a power supply unit, wherein the power supply unit supplies power to the first to M photodiodes for a first time before scanning.

And, the first time is 1 μs, providing a LiDAR system.

In addition, the control unit provides a LIDAR system that generates the i-th trigger signal and then receives the first to L-th low voltage differential signals for a second time.

And, the second time is 8.5ns, providing a lidar system.

In addition, the control unit generates the first to Nth trigger signals at third time intervals, generates the Nth trigger signal, and then waits for the third time.

And, the third time is 1 μs, providing a LiDAR system.

And, it further includes a rotation driver, wherein the control unit rotates the rotation driver by the horizontal resolution after the fourth time has elapsed.

And, the fourth time is 30 μs, providing a LiDAR system.

The present invention can improve precision when measuring the distance to an object by including one or more channels. Since the first LiDAR receiver and the second LiDAR receiver can receive the reflected beam of one laser line beam, accuracy can be improved when measuring the distance to an object.

Figure 1a is a block diagram briefly showing a lidar system according to an embodiment of the present invention.
Figure 1B is a block diagram briefly showing the configuration of a laser transmitter in an embodiment of the present invention.
Figure 1C is a block diagram briefly showing the configuration of an optical unit in one embodiment of the present invention.
Figure 1D is a block diagram briefly illustrating the configuration of a first laser receiver in an embodiment of the present invention.
Figure 1e is a perspective view briefly showing the operation of the rotation driving unit in one embodiment of the present invention.
Figure 2 is a flow chart briefly showing the scanning method of the LIDAR system in one embodiment of the present invention.
Figure 3a briefly shows a timing diagram when the LIDAR system scans in the vertical direction, in one embodiment of the present invention.
Figure 3b briefly shows a timing diagram when the LIDAR system scans in the horizontal direction, in one embodiment of the present invention.

The present invention can be implemented with various changes without departing from the spirit, and can have one or more embodiments. In addition, in the present invention, the embodiments described in “specific details for carrying out the invention” and “drawings” are examples for specifically explaining the present invention, and do not limit or limit the scope of the present invention.

Accordingly, what a person skilled in the art of the present invention can easily infer from the “specific details for carrying out the invention” and “drawings” of the present invention shall be interpreted as falling within the scope of the present invention. can do.

In addition, the size and shape of each component shown in the drawings may be exaggerated for description of the embodiment, and do not limit the size and shape of the invention in actual practice.

Unless the terms used in the specification of the present invention are specifically defined, they may have the same meaning as those generally understood by those skilled in the art to which the present invention pertains.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1a is a block diagram briefly showing a lidar system according to an embodiment of the present invention.

The LiDAR system 100 according to an embodiment of the present invention includes a laser transmitter 110, an optical unit 120, a laser receiver 130, a control unit 140, a rotation driver 150, It may include a power supply unit 160.

FIG. 1B is a block diagram briefly illustrating the configuration of the laser transmitter 110 in an embodiment of the present invention.

The laser transmitter 110 can generate a pulse laser and emit the generated pulse laser to the outside of the LIDAR system 100.

The laser transmitter 110 may include a laser diode module 111 and a laser driver module 112.

The laser diode module 111 can generate pulse laser.

The laser diode module 111 receives first to Nth laser generation signals (LDS ₁ to LDS _N ) from the laser driver module 112, respectively, and then generates first to Nth pulse lasers (PL ₁ to LDS N), which are pulse lasers. PL _N ) can be generated and transmitted to the optical unit 120, respectively.

The laser diode module 111 may be a laser diode array. The laser diode module 111 may include N laser diodes (LD ₁ to LD _N ) (N is a natural number) and generate first to N pulse lasers (PL ₁ to PL _N ). For example, the laser diode module 111 may include four laser diodes (LD ₁ to LD ₄ ) and generate first to fourth pulse lasers (PL ₁ to PL ₄ ). And the pulse lasers (PL ₁ to PL _N ) generated for each laser diode (LD ₁ to LD _N ) can each have a power of 75W. Additionally, the interval between the pulse lasers (PL ₁ to PL _N ) may be 30 μm, and the width of the pulse lasers (PL ₁ to PL _N ) may be 280 μm.

The laser driver module 112 may generate first to Nth laser generation signals (LDS ₁ to LDS _N ), which are pulse signals, and then transmit them to the laser diode module 111.

The laser driver module 112 may include a half-bridge gate driver, a GaN FET driver, a logic level MOSFET driver, and a power transistor. The laser driver module 112 may generate pulse signals corresponding to each of the first to N laser diodes (LD ₁ to LD _N ), and generate first to N laser generation signals (LDS ₁ to LDS) that are pulse signals. _N ) can be transmitted to the laser diode module 111. For example, the laser driver module 112 may generate the first to fourth laser generation signals (LDS ₁ to LDS ₄ ) and then transmit them to the laser diode module 111.

The laser driver module 112 receives the first to Nth trigger signals (TRG ₁ to TRG _N ) from the control unit 140, and then generates the first to Nth laser generation signals (LDS ₁ to LDS) in response to the trigger signals. _N ) can be created.

Figure 1C is a block diagram briefly showing the configuration of the optical unit 120 in one embodiment of the present invention.

The optical unit 120 can generate one laser line beam by collecting one or more pulsed lasers, and can focus the reflected beam that is reflected from the object and returned.

The optical unit 120 may include a line lens 121, a first light receiving lens 122, and a second light receiving lens 123.

The line lens 121 receives the first to Nth pulse lasers (PL ₁ to PL _N ) from the laser diode module 111, and then moves in the first direction D1, which is a direction perpendicular to the line lens 121. As a reference, one laser line beam (LLB) formed between the first emission angle (EA ₁ ) and the second emission angle (EA ₂ ) can be generated. For example, the line lens 121 receives the first to fourth pulse lasers (PL ₁ to PL ₄ ) from the laser diode module 111 and then moves them in the second direction (D2) based on the first direction (D1). ) can generate a laser line beam (LLB) that forms a one-dimensional line within a range of 10° in the third direction (D3) and 10° in the third direction (D3). At this time, the first emission angle (EA ₁ ) is 10°, and the second emission angle (EA ₂ ) is -10°. Accordingly, it is possible to measure whether an object or a part of an object is located in an area where one laser line beam (LLB) is irradiated in the vertical direction and the distance to the object or a part of the object.

The first light receiving lens 122 and the second light receiving lens 123 each collect the reflected beam (RB) reflected from the object and returned to the LIDAR system 100, and transmit the light to the first laser receiver 131 and the second laser. It can be transmitted to the receiving unit 132.

FIG. 1D is a block diagram briefly illustrating the configuration of the first laser receiver 131 in an embodiment of the present invention. FIG. 1D representatively shows the configuration of the first laser receiver 131, and the configuration of the second laser receiver 132 may be the same as that of FIG. 1D.

The laser receiver 130 can detect the reception of the reflected beam RB at each incident angle.

The laser receiver 130 may include a first laser receiver 131 and a second laser receiver 132. The first laser receiver 131 and the second laser receiver 132 may include a photo diode module (APD), a multiplexer module (MUX), and a low-voltage differential signal generation module (COMP), respectively.

The photo diode module (APD) can detect whether the reflected beam (RB) reflected from an object and returned to the LiDAR system 100 is received.

The photo diode module (APD) may include M photo diodes (APD ₁ to APD _M ). For example, a photo diode module (APD) may include 16 photo diodes (APD ₁ to APD ₁₆ ).

The first to M photodiodes (APD ₁ to APD _M ) may be located in an array form, and each may detect whether or not light is received according to the incident angle of the reflected beam (RB). The j photodiode (APD _j ) is reflected when the reflected beam RB returns to the LIDAR system 100 within the range of the j incident angle (IA _j ) to the j+1 incident angle (IA _j+1 ). After receiving the beam RB, a jth light-receiving signal RLS _j having a first voltage V1 may be generated. (1≤j≤M, j is a natural number) or the jth photodiode (APD _j ) is a reflected beam (RB) within the range of the jth incident angle (IA _j ) to the j+1th incident angle (IA _j+1 ). If the light is not received, the jth light-receiving signal (RLS _j ) with the second voltage (V2) can be generated. The j photodiode (APD _j ) can transmit the generated j light reception signal (RLS _j ) to the multiplexer module (MUX).

The multiplexer module (MUX) can select the light reception signal received from the photo diode module (APD).

The multiplexer module (MUX) may include L multiplexers (MUX ₁ to MUX _L ). The number (L) of multiplexers (MUX ₁ to MUX _L ) may be the number of photodiodes (APD ₁ to APD _M ) divided by the number (N) of laser diodes (LD ₁ to LD _N ). there is. (L = M/N) For example, a multiplexer module (MUX) may include four multiplexers (MUX ₁ to MUX ₄ ).

The first to M photodiodes (APD ₁ to APD _M ) may be sequentially and cyclically connected to the first to L multiplexers (MUX ₁ to MUX _L ). The first to L photodiodes (APD ₁ to APD _L ) may be connected to the first to L multiplexers (MUX ₁ to MUX _L ), respectively. The L+1 to 2L photodiodes (APD _L+1 to APD _2L ) may be connected to the first to L multiplexers (MUX ₁ to MUX _L ), respectively. The kL+1 to (k+1)L photodiodes (APD _kL+1 to APD _(k+1)L ) may be connected to the first to L multiplexers (MUX ₁ to MUX _L ), respectively. . (0≤k<N, where k is an integer)

For example, when the LiDAR system 100 includes 4 laser diodes (LD ₁ to LD ₄ ), 16 photo diodes (APD ₁ to APD ₁₆ ), and 4 multiplexers (MUX ₁ to MUX ₄ ) , the first to fourth photodiodes (APD ₁ to APD ₄ ) may be connected to the first to fourth multiplexers (MUX ₁ to MUX ₄ ), respectively. The fifth to eighth photodiodes (APD ₅ to APD ₈ ) may be connected to the first to fourth multiplexers (MUX ₁ to MUX ₄ ), respectively. The ninth to twelfth photodiodes (APD ₉ to APD ₁₂ ) may be connected to the first to fourth multiplexers (MUX ₁ to MUX ₄ ), respectively. The 13th to 16th photodiodes (APD ₁₃ to APD ₁₆ ) may be connected to the first to fourth multiplexers (MUX ₁ to MUX ₄ ), respectively.

The first to L multiplexers (MUX ₁ to MUX _L ) may receive a selection signal (SEL) from the control unit 140. The selection signal (SEL) may consist of log ₂ N bits. The operation of sequentially increasing the value of the selection signal (SEL) by 1 from 0 to N-1 and then initializing it back to 0 may be repeatedly performed.

When the value of the selection signal (SEL) is 0, the first to L multiplexers (MUX ₁ to MUX _L ) receive the first to L photo diodes (APD ₁ to APD _L ), respectively. The Lth light reception signal (RLS ₁ to RLS _L ) can be output. When the value of the selection signal (SEL) is 1, the first to L multiplexers (MUX ₁ to MUX _L ) receive each from the L+1 to 2L photodiodes (APD _L+1 to APD _2L ). One L+1 to 2L light-receiving signal (RLS _L+1 to RLS _2L ) can be output. When the value of the selection signal (SEL) is k, the first to L-th multiplexers (MUX ₁ to MUX _L ) are respectively connected to the kL+1 to (k+1)-th photodiodes (APD _kL+1 to The kL _{+1 to (k+1} )L light reception signals (RLS _kL+1 to RLS _{(k+1)L) received from the APD (k+1)L} ) can be output. (0≤k<N, where k is an integer)

For example, when the LiDAR system 100 includes 4 laser diodes (LD ₁ to LD ₄ ), 16 photo diodes (APD ₁ to APD ₁₆ ), and 4 multiplexers (MUX ₁ to MUX ₄ ) , when the value of the selection signal (SEL) is 0, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) receive the first photo diode (APD 1 to APD 4) from the first to fourth photodiodes (APD ₁ to APD ₄ ), respectively. to fourth light-receiving signals (RLS ₁ to RLS ₄ ) can be output. When the value of the selection signal (SEL) is 1, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) receive the fifth to eighth photodiodes (APD ₅ to APD ₈ ), respectively. The eighth light reception signal (RLS ₅ to RLS ₈ ) can be output. When the value of the selection signal (SEL) is 2, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) receive the 9th to 12th photo diodes (APD ₉ to APD ₁₂ ), respectively. The twelfth light reception signal (RLS ₉ to RLS ₁₂ ) can be output. When the value of the selection signal (SEL) is 3, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) receive the 13th to 16th photodiodes (APD ₁₃ to APD ₁₆ ), respectively. The 16th light reception signal (RLS ₁₃ to RLS ₁₆ ) can be output.

The low-voltage differential signal generation module (COMP) can generate a logic level in response to the light-receiving signal selected by the multiplexer module (MUX).

The low-voltage differential signal generation module (COMP) may include L comparators (COMP ₁ to COMP _L ) equal to the number of multiplexers. For example, a low-voltage differential signal generation module (COMP) may include four comparators (COMP ₁ to COMP ₄ ).

The first to L comparators (COMP ₁ to COMP _L ) correspond to the light-receiving signals selected by the first to L multiplexers (MUX ₁ to MUX _L ), respectively, and generate the first to L low voltage differential signals (LVDS ₁₎ . ~ LVDS _L ) can be generated.

When the light-receiving signals each have a first voltage (V1), the first to L comparators (COMP ₁ to COMP _L ) may generate a low-voltage differential signal with a logic high level.

When each light-receiving signal has a second voltage (V2), the first to L comparators (COMP ₁ to COMP _L ) may generate a low-voltage differential signal with a logic low level.

The voltage difference between the low-voltage differential signal with a logic high level and the low-voltage differential signal with a logic low level may be 260 mV to 420 mV. The first to L comparators (COMP ₁ to COMP _L ) generate low-voltage differential signals with small swings, thereby reducing power consumption and increasing transmission speed.

The control unit 140 can control the laser transmitter 110 to generate a pulse laser and the laser receiver 130 to select and sequentially output light-receiving signals.

The control unit 140 may generate N trigger signals (TRG ₁ to TRG _N ) equal to the number of laser diodes (LD ₁ to LD _N ) and then transmit them to the laser driver module 112. For example, the control unit 140 may generate the first to fourth trigger signals TRG ₁ to TRG ₄ and then transmit them to the laser driver module 112.

The first to Nth trigger signals (TRG ₁ to TRG _N ) are signals that control the laser diode module 111 to generate the first to Nth pulse lasers (PL ₁ to PL _N ), respectively. The laser driver module 112 may generate first to Nth laser generation signals ( _LDS1 to _LDSN ) in response to the first to Nth trigger signals ( _TRG1 to TRGN ₎ .

The control unit 140 may change the value of the selection signal SEL according to the driving time. The control unit 140 may increase the value of the selection signal SEL by 1 for each selection interval SI. The control unit 140 may sequentially increase the value of the selection signal SEL by 1 from 0 to N-1 and then repeatedly initialize it to 0.

The control unit 140 generates first to L low voltage differential signals (LVDS ₁ to LVDS _L ) having a logic level corresponding to the light reception signal selected by the multiplexer module (MUX) according to the value of the set selection signal (SEL). ) can be received.

The control unit 140 may calculate the difference between the time the trigger signal is generated and the time the low-voltage differential signal is received as the arrival time. The control unit 140 calculates the difference between the time of generating the i trigger signal (TRG _i ) and the time of receiving each of the first to L low voltage differential signals (LVDS ₁ to LVDS _L ) as (i-1) It can be calculated as the arrival time from L+1 to the iL (TOF _(i-1)L+1 to TOF _iL ).

For example, when the LiDAR system 100 includes 4 laser diodes (LD ₁ to LD ₄ ), 16 photo diodes (APD ₁ to APD ₁₆ ), and 4 multiplexers (MUX ₁ to MUX ₄ ) , the control unit 140 calculates the difference between the time of generating the first trigger signal (TRG ₁ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ). It can be calculated by arrival time (TOF ₁ to TOF ₄ ). The control unit 140 calculates the difference between the time of generating the second trigger signal (TRG ₂ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ), It can be calculated by time (TOF ₅ ~ TOF ₈ ). The control unit 140 calculates the difference between the time of generating the third trigger signal (TRG ₃ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ), It can be calculated by time (TOF ₉ ~ TOF ₁₂ ). The control unit 140 calculates the difference between the time of generating the fourth trigger signal (TRG ₄ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ), reaching the 13th to 16th It can be calculated by time (TOF ₁₃ ~ TOF ₁₆ ).

If the low-voltage differential signal is not received during the second time T2 after generating the trigger signal, the control unit 140 determines that there is no object or part of the object that reflected the pulse laser within the range of the incident angle measured by the photo diode. It can be judged that

That is, after generating the i trigger signal (TRG _i ), if the first to L low voltage differential signals (LVDS ₁ to LVDS _L ) are not received during the second time (T2), the (i-1) It can be determined that there is no object or part of the object that reflected the pulse laser within the range of the incident angle measured by each of the L+1 to iL photodiodes (APD _(i-1)L+1 to APD _iL ).

Figure 1e is a perspective view briefly showing the operation of the rotation driver 150 in one embodiment of the present invention.

The rotation driver 150 can rotate the configuration of the LiDAR system 100.

The rotation driver 150 may include a brushless DC (BLDC) motor. The rotation driver 150 can accommodate the laser transmitter 110, the optical unit 120, and the laser receiver 130, or can be connected to these components and rotate them within the horizontal scan range (HSR). The horizontal displacement angle HDA is the angle difference between the displacement line DL of the rotation driver 150 with respect to the reference line BL in the fourth direction D4. The horizontal scan range (HSR) is an angle range in which the rotation driver 150 can rotate, and may be, for example, 0° to 360°. The horizontal resolution (HR) is the angular interval at which the laser transmitter 110 emits the laser line beam (LLB), and may be, for example, 0.125° to 0.25°. Accordingly, one or more laser line beams (LLBs) are generated per horizontal resolution (HR), allowing detection of objects or parts of objects located in the horizontal scan range (HSR).

The power supply unit 160 may supply power to the components of the LiDAR system 100.

For example, the power supply unit 160 can supply power with a voltage of 74V to the laser diode module 111, and supply power with a voltage of -60V to 170V to the photo diode module (APD), and the control unit ( 140), power with a voltage of 5V can be supplied.

Figure 2 is a flow chart briefly showing the scanning method of the LIDAR system in one embodiment of the present invention. Figure 3a briefly shows a timing diagram when the LIDAR system scans in the vertical direction, in one embodiment of the present invention. Figure 3b briefly shows a timing diagram when the LIDAR system scans in the horizontal direction, in one embodiment of the present invention.

In one embodiment of the present invention, the scanning method (S1 to S12) of the LIDAR system is as follows.

In the description, N refers to the number of trigger signals, laser generation signals, laser diodes, and pulse lasers. M is the number of photodiodes and light-receiving signals. L is the number of multiplexers and low-voltage differential signals and is equal to M/N. In Figures 5 and 6, M is 16, N is 4, and L is 4 as an example.

In the first step (S1), the power supply unit 150 supplies power to the laser receiver 130.

The power supply unit 150 may supply power to the photo diode module (APD) for a first time T1 so that the photo diode module (APD) can receive the reflected beam RB and generate a light-receiving signal, which is an electrical signal. there is. For example, the first time (T1) may be 1 μs.

In the second step (S2), the control unit 140 generates a trigger signal and then transmits it to the laser transmitter 110.

The control unit 140 may generate the ith trigger signal (TRG _i ) and then transmit it to the laser driver module 112. At this time, i is initially set to 1, and increases by 1 when performing the second to tenth steps (S1 to S10) and then performing the second step again. That is, by repeatedly performing the second step (S2), the control unit 140 can sequentially generate the first to Nth trigger signals (TRG ₁ to TRG _N ). After the laser transmitter 110 generates one laser line beam (LLB), i may be initialized to 1.

In the third step (S3), the laser transmitter 110 generates a pulse laser and then transmits it to the optical unit 120.

The laser driver module 112 may generate the i-th laser generation signal (LDS _i ) in response to the i-th trigger signal (TRG _i ) and then transmit it to the laser diode module 111. By repeating the third step (S3), the laser driver module 112 can sequentially generate the first to Nth laser generation signals (LDS ₁ to LDS _N ).

The laser diode module 111 may generate the i-th pulse laser (PL _i ) in response to the i-th laser generation signal (LD _i ) and then transmit it to the line lens 121. By repeating the third step (S3), the laser diode module 111 can sequentially generate first to Nth pulse lasers (PL ₁ to PL _N ).

The fourth step (S4) is a step in which the optical unit 140 refracts the pulse laser and emits it to the outside of the LIDAR system 100.

The line lens 121 may refract the ith pulse laser (PL _i ) and emit it to the outside of the LiDAR system 100 . By repeating the fourth step (S4), the line lens 121 may sequentially emit the first to Nth pulse lasers (PL ₁ to PL _N ).

The fifth step (S5) is a step in which the optical unit 140 receives the reflected beam RB.

The first light receiving lens 122 and the second light receiving lens 123 can each collect the reflected beam RB that is reflected from an object and then transmit it to the photo diode module (APD).

The sixth step (S6) is a step in which the photo diode module (APD) generates a light reception signal.

Each of the L photodiodes can detect whether or not the reflected beam RB is received within the range of the incident angle that it measures, and then generate a light reception signal in response.

The j photodiode (APD _j ) is reflected when the reflected beam RB returns to the LIDAR system 100 within the range of the j incident angle (IA _j ) to the j+1 incident angle (IA _j+1 ). After receiving the beam RB, a jth light-receiving signal RLS _j having a first voltage V1 may be generated.

Alternatively, when the j photodiode (APD _j ) fails to receive the reflected beam (RB) within the range of the j incident angle (IA _j ) to the j+1 incident angle (IA _j+1 ), the second voltage (V2) The jth light reception signal (RLS _j ) with can be generated.

For example, when the first pulse laser (PL1) is reflected by an object and returns, the first photodiode (APD ₁ ) reflects the reflected beam (RB) within the range of the first incident angle (IA ₁ ) to the second incident angle (IA ₂ ). ) is detected, and then the first light reception signal (RLS ₁ ) can be generated. The second photo diode (APD ₂ ) detects whether or not the reflected beam (RB) is received within the range of the second incident angle (IA ₂ ) to the third incident angle (IA ₃ ), and then generates a second light reception signal (RLS ₂ ). can do. The third photo diode (APD ₃ ) detects whether or not the reflected beam (RB) is received within the range of the third incident angle (IA ₃ ) to the fourth incident angle (IA ₄ ) and then generates the third light reception signal (RLS ₃ ). can do. The fourth photo diode (APD ₄ ) detects whether the reflected beam (RB) is received within the range of the fourth incident angle (IA ₄ ) to the fifth incident angle (IA ₅ ) and then generates the fourth light reception signal (RLS ₄ ). can do. When the second pulse laser (PL2) is reflected by the object and returns, the fifth photo diode (APD ₅ ) receives the reflected beam (RB) within the range of the fifth incident angle (IA ₅ ) to the sixth incident angle (IA ₆ ). After detecting the presence or absence, a fifth light receiving signal (RLS ₅ ) can be generated. The sixth photo diode (APD ₆ ) detects whether or not the reflected beam (RB) is received within the range of the sixth incident angle (IA ₆ ) to the seventh incident angle (IA ₇ ), and then generates the sixth light reception signal (RLS ₆ ). can do. The seventh photodiode (APD ₇ ) detects whether or not the reflected beam (RB) is received within the range of the seventh incident angle (IA ₇ ) to the eighth incident angle (IA ₈ ), and then generates the seventh light reception signal (RLS ₇ ). can do. The eighth photo diode (APD ₈ ) detects whether or not the reflected beam (RB) is received within the range of the eighth incident angle (IA ₈ ) to the ninth incident angle (IA ₉ ), and then generates the eighth light reception signal (RLS ₈ ). can do. When the third pulse laser (PL3) is reflected by the object and returns, the ninth photo diode (APD ₉ ) receives the reflected beam (RB) within the range of the ninth incident angle (IA ₉ ) to the tenth incident angle (IA ₁₀ ). After detecting whether or not the light is detected, a ninth light receiving signal (RLS ₉ ) can be generated. The tenth photo diode (APD ₁₀ ) detects whether the reflected beam (RB) is received within the range of the tenth incident angle (IA ₁₀ ) to the eleventh incident angle (IA ₁₁ ), and then generates the tenth light reception signal (RLS ₁₀ ). can do. The 11th photo diode (APD ₁₁ ) detects whether or not the reflected beam (RB) is received within the range of the 11th incident angle (IA ₁₁ ) to the 12th incident angle (IA ₁₂ ), and then generates the 11th light reception signal (RLS ₁₁ ). can do. The twelfth photo diode (APD ₁₂ ) detects whether or not the reflected beam (RB) is received within the range of the twelfth incident angle (IA ₁₂ ) to the thirteenth incident angle (IA ₁₃ ), and then generates the twelfth light reception signal (RLS ₁₂ ). can do. When the fourth pulse laser PL4 is reflected by an object and returns, the 13th photo diode APD ₁₃ receives the reflected beam RB within the range of the 13th incident angle IA ₁₃ to the 14th incident angle IA ₁₄ . After detecting whether or not the light is received, the 13th light receiving signal (RLS ₁₃ ) can be generated. The fourteenth photo diode (APD ₁₄ ) detects whether the reflected beam (RB) is received within the range of the fourteenth incident angle (IA ₁₄ ) to the fifteenth incident angle (IA ₁₅ ) and then generates the fourteenth light reception signal (RLS ₁₄ ). can do. The 15th photo diode (APD ₁₅ ) detects whether or not the reflected beam (RB) is received within the range of the 15th incident angle (IA ₁₅ ) to the 16th incident angle (IA ₁₆ ), and then generates the 15th light reception signal (RLS ₁₅ ). can do. The 16th photo diode (APD ₁₆ ) detects whether the reflected beam (RB) is received within the range of the 16th incident angle (IA ₁₆ ) to the 17th incident angle (IA ₁₇ ), and then generates the 16th light reception signal (RLS ₁₆ ). can do.

By repeating the sixth step (S6), light-receiving signals can be sequentially generated for each of the L photodiodes according to whether or not the reflected beam RB is received. That is, when the i pulse laser (PL _i ) is reflected by an object and returns as a reflected beam (RB), the (i-1)L+1 to iL photodiodes (APD _(i-1)L+1 to APD _iL ) may generate (i-1)L+1 to iL-th light reception signals (RLS _(i-1)L+1 to RLS _iL ), respectively.

The seventh step (S7) is a step in which the control unit 140 sets the value of the selection signal (SEL).

The control unit 140 may set the value of the selection signal (SEL) to i-1 and then transmit it to the first to Lth multiplexers (MUX ₁ to MUX _L ). By repeating the seventh step (S7), the control unit 140 can sequentially increase the value of the selection signal (SEL) from 0 to N-1. And when the value of the selection signal SEL is increased to N, the control unit 140 may initialize it to 0.

The eighth step (S8) is a step in which the multiplexer module (MUX) outputs a light-receiving signal.

According to the value (k) of the selection signal (SEL) set by the control unit 140, the first to L multiplexers (MUX ₁ to MUX _L ) are connected to the kL+1 to (k+1)th ports, respectively. Select the connection with the diode (APD _kL+1 to APD _(k+1)L ), then connect the kL+1 to (k+1)L light receiving signals (RLS _kL+1 to RLS _(k+1)L ). Can be printed. (0≤k<N, where k is an integer)

For example, when the control unit 140 sets the selection signal (SEL) to 0, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) respectively operate the first to fourth photodiodes (APD ₁ to APD) ₄ ), then the first to fourth light receiving signals (RLS ₁ to RLS ₄ ) can be output. When the control unit 140 sets the selection signal (SEL) to 1, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) are connected to the fifth to eighth photodiodes (APD ₅ to APD ₈ ), respectively. After selecting the connection, the fifth to eighth light-receiving signals (RLS ₅ to RLS ₈ ) can be output. When the control unit 140 sets the selection signal (SEL) to 2, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) are connected to the ninth to twelfth photodiodes (APD ₉ to APD ₁₂ ), respectively. After selecting the connection, the 9th to 12th light reception signals (RLS ₉ to RLS ₁₂ ) can be output. When the control unit 140 sets the selection signal (SEL) to 3, the first to fourth multiplexers (MUX ₁ to MUX ₄ ) are connected to the 13th to 16th photodiodes (APD ₁₃ to APD ₁₆ ), respectively. After selecting the connection, the 13th to 16th light reception signals (RLS ₁₃ to RLS ₁₆ ) can be output.

The ninth step (S9) is a step in which the low-voltage differential signal generation module (COMP) generates a logic level in response to the received light signal.

The first to L comparators (COMP ₁ to COMP _N ) correspond to the light reception signals selected by the first to L multiplexers (MUX ₁ to MUX _L ), respectively, and provide a first to L low voltage differential with a logic level. Signals (LVDS ₁ to LVDS _L ) can be generated. The first to L comparators (COMP ₁ to COMP _L ) may transmit the generated first to L low voltage differential signals (LVDS ₁ to LVDS _L ) to the control unit 140, respectively.

By repeating the ninth step (S9), low-voltage differential signals can be sequentially generated by each L comparator in response to the received light signal.

The tenth step (S10) is a step in which the control unit 140 calculates the arrival time.

The control unit 140 may calculate the difference between the time at which the trigger signal is generated and the time at which the low-voltage differential signal is received in the second step (S2) as the arrival time. The control unit 140 calculates the difference between the time of generating the i trigger signal (TRG _i ) and the time of receiving each of the first to L low voltage differential signals (LVDS ₁ to LVDS _L ) as (i-1) It can be calculated as the arrival time from L+1 to the iL (TOF _(i-1)L+1 to TOF _iL ).

For example, the control unit 140 calculates the difference between the time of generating the first trigger signal (TRG ₁ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ). It can be calculated as the fourth arrival time (TOF ₁ to TOF ₄ ). The control unit 140 calculates the difference between the time of generating the second trigger signal (TRG ₂ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ) to reach the fifth to eighth It can be calculated by time (TOF ₅ ~ TOF ₈ ). The control unit 140 calculates the difference between the time of generating the third trigger signal (TRG ₃ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ), It can be calculated by time (TOF ₉ ~ TOF ₁₂ ). The control unit 140 calculates the difference between the time of generating the fourth trigger signal (TRG ₄ ) and the time of receiving each of the first to fourth low voltage differential signals (LVDS ₁ to LVDS ₄ ), reaching the 13th to 16th It can be calculated by time (TOF ₁₃ ~ TOF ₁₆ ).

The second to tenth steps (S2 to S10) may be performed for a second time (T2). For example, the second time (T2) may be 8.5 ns.

If the low-voltage differential signal is not received during the second time T2 after generating the trigger signal, the control unit 140 determines that there is no object or part of the object that reflected the pulse laser within the range of the incident angle measured by the photo diode. It can be judged that

That is, after generating the i trigger signal (TRG _i ), if the first to L low voltage differential signals (LVDS ₁ to LVDS _L ) are not received during the second time (T2), the (i-1) It can be determined that there is no object or part of the object that reflected the pulse laser within the range of the incident angle measured by each of the L+1 to iL photodiodes (APD _(i-1)L+1 to APD _iL ).

The eleventh step (S11) is a step in which the control unit 140 determines whether scanning in the vertical direction is complete.

In the 11th step (S11), it is determined whether the generation of one laser line beam (LLB) in the vertical direction has been completed. The control unit 140 may determine whether all of the first to Nth trigger signals TRG ₁ to TRG _N have been sequentially generated after the third time T3 has elapsed. For example, the third time (T3) may be 1 μs.

When the Nth trigger signal (TRG _N ), which is the last trigger signal, is generated, the control unit 140 may proceed to the next twelfth step (S12).

If not, the control unit 140 may proceed with the second step (S2) again.

The twelfth step (S12) is a step in which the control unit 140 determines whether scanning in the horizontal direction is complete.

The twelfth step (S12) is a step of determining whether scanning has been completed in the horizontal scan range (HSR). When the horizontal displacement angle (HDA) of the rotation driver 150 is smaller than the horizontal scan range (HSR), the control unit 140 controls the rotation driver 150 after the fourth time T4 has elapsed to the horizontal resolution (HR). You can rotate it as much as you want and proceed with the first to eleventh steps (S1 to S11) again. For example, the fourth time (T4) may be 30 μs.

When the horizontal displacement angle (HDA) of the rotation driver 150 exceeds the horizontal scan range (HSR), the control unit 140 may determine that scanning in the horizontal direction has been completed and end the step.

The LIDAR system 100 may generate H laser line beams (LLB) for each horizontal resolution (HR) within the horizontal scan range (HSR) and emit them to the outside. Since one or more photodiodes (APD ₁ to APD _M ) can detect whether or not the reflected beam (RB) is received within the range of the incident angle that it measures, precision can be improved when measuring the distance to an object. In addition, since the first LiDAR receiver 131 and the second LiDAR receiver 132 can receive the reflected beam (RB) for one laser line beam (LLB), when measuring the distance to an object Accuracy can be improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be varied within the scope of the detailed description and accompanying drawings, as long as it does not deviate from the spirit of the present invention and does not impair the effect. It can be implemented by changing it accordingly. It is also natural that such embodiments fall within the scope of the present invention.

100: Lidar system
110: Laser transmitter 111: Laser diode module
112: Laser driver module 120: Optics unit
121: Line lens 122: First light receiving lens
123: second light receiving lens 130: laser receiver
131: first laser receiver 132: second laser receiver
APD ₁ to APD _M : 1st to 1st M photodiodes
MUX ₁ to MUX _L : first to L multiplexers
COMP ₁ to COMP _L : 1st to L comparators
140: Control unit 150: Rotation driving unit
160: power unit

Claims (14)

A laser transmitter; a first laser receiver; It includes a second laser receiver,
The laser transmitter,
It includes first to N laser diodes that generate pulsed lasers,
The first laser receiver and the second laser receiver, respectively,
First to M photodiodes that detect whether light is received according to the incident angle of the reflected beam and generate a light reception signal;
first to L multiplexers that select and connect one of the first to M photodiodes according to a selection signal; (L = M/N)
In response to the light-receiving signal, it includes first to L-th comparators that generate a low-voltage differential signal with a logic level,
Further comprising a control unit,
The control unit transmits first to Nth trigger signals to the laser transmitter,
The first to Nth laser diodes generate first to Nth pulse lasers in response to the first to Nth trigger signals, respectively,
The first to M photodiodes each have,
When receiving the reflected beam, generate first to M light-receiving signals having a first voltage,
Generating first to M light-receiving signals with a second voltage when the reflected beam is not received,
The control unit initializes the value (k) of the selection signal to 0, then increases the value (k) of the selection signal by 1 at each selection interval, and when the increased value (k) of the selection signal is N Initialize to 0,
The kL+1th to (k+1)th photodiodes are respectively connected to the first to Lth multiplexers,
The first to Lth multiplexers output kL+1th to (k+1)th light-receiving signals, respectively.
LIDAR system.
delete delete delete According to claim 1,
The first to L comparators are, respectively,
When the kL+1 to (k+1)Lth light-receiving signals have the first voltage, generate first to Lth low voltage differential signals having a logic high level,
When the kL+1 to (k+1)Lth light-receiving signals have the second voltage, generating the first to Lth low voltage differential signals having a logic low level,
LIDAR system.
According to claim 5,
The control unit calculates the difference between the time of generating the i-th trigger signal and the time of receiving each of the first to Lth low-voltage differential signals as (i-1)L+1 to iLth arrival times, (1≤i≤N, i is a natural number)
LIDAR system.
According to claim 6,
Further including a power supply unit,
The power supply unit supplies power to the first to M photodiodes for a first time before scanning,
LIDAR system.
According to claim 7,
The first time is 1 μs,
LIDAR system.
According to claim 7,
The control unit generates the i th trigger signal and then receives the first to L th low voltage differential signals for a second time,
LIDAR system.
According to clause 9,
wherein the second time is 8.5 ns,
LIDAR system.
According to clause 9,
The control unit generates the first to Nth trigger signals at third time intervals, generates the Nth trigger signal, and then waits for the third time,
LIDAR system.
According to claim 11,
wherein the third time is 1 μs,
LIDAR system.
According to claim 11,
Further comprising a rotary drive unit,
The control unit rotates the rotation drive unit by the horizontal resolution after the fourth time has elapsed,
LIDAR system.
According to claim 13,
wherein the fourth time is 30 μs,
LIDAR system.