CN111670378A

CN111670378A - Light emitting device, distance measuring device and mobile platform

Info

Publication number: CN111670378A
Application number: CN201980005426.7A
Authority: CN
Inventors: 黄森洪; 马亮亮; 刘祥
Original assignee: SZ DJI Technology Co Ltd
Current assignee: SZ DJI Technology Co Ltd
Priority date: 2019-01-09
Filing date: 2019-01-09
Publication date: 2020-09-15
Also published as: WO2020142947A1

Abstract

A light emitting device comprises a power supply, a laser emitter (1), a charging circuit, a tank circuit and a control circuit, wherein the control circuit is used for cutting off the connection between the laser emitter (1) and the tank circuit in a first period, and the charging circuit is used for charging the tank circuit in at least part of the first period; the control circuit is also used for conducting the connection between the laser transmitter (1) and the energy storage circuit in a second time period, so that the energy storage circuit supplies power to the laser transmitter (1) to enable the laser transmitter (1) to emit a light pulse signal until the output current of the capacitor (C1) is lower than the threshold current of the laser transmitter (1); the first and second periods are alternated so that the laser emitter (1) emits a sequence of laser pulses, the light emitting device ensuring an output value in accordance with a prescribed value for human eye safety. A ranging apparatus including the light emitting apparatus and a mobile platform including the ranging apparatus are also provided.

Description

Light emitting device, distance measuring device and mobile platform

Technical Field

The invention relates to the technical field of circuits, in particular to a light emitting device, a distance measuring device and a mobile platform.

Background

In the fields of laser radar, laser ranging and the like, because products are directly used in real life scenes, laser has the risk of directly emitting into human eyes, and therefore, the Access Emission Limit (AEL) specifies that the laser Emission cannot exceed the energy value specified by safety, so that the human body cannot be injured even if the laser is emitted into the human eyes. Further, any device has the possibility of failure, so that the damage to a human body is reduced as much as possible to avoid the failure of the device or the control of a system. Therefore, AEL requires that the laser emission energy also not exceed the safety-specified value when a single failure of the system occurs.

The invention designs a laser emission scheme which accords with the safety regulation of human eyes, and meanwhile, when a system has single fault, the protection circuit can ensure that the laser energy does not exceed the safety regulation value.

Disclosure of Invention

A first aspect of the present invention provides a light emitting device comprising: the laser power supply comprises a power supply, a laser transmitter, a charging circuit, an energy storage circuit and a control circuit, wherein the power supply is connected with the charging circuit and is used for charging the charging circuit for at least part of time; the energy storage circuit is respectively connected with the laser transmitter and the charging circuit, the energy storage circuit comprises at least one capacitor, and the charging circuit comprises at least one inductor; the control circuit is used for cutting off the connection between the laser transmitter and the energy storage circuit in a first time period, and the charging circuit is used for charging the energy storage circuit in at least part of the time period of the first time period; the control circuit is further used for conducting connection between the laser transmitter and the energy storage circuit in a second time interval, so that the energy storage circuit supplies power to the laser transmitter, the laser transmitter emits light pulse signals until the output current of the capacitor is lower than the threshold current of the laser transmitter; the first time period and the second time period alternate such that the laser emitter emits a sequence of laser pulses.

Further, the energy stored by the at least one capacitor has a preset upper limit value.

Further, the control circuit comprises a first switch circuit and a drive circuit connected with the first switch circuit; the driving circuit is used for controlling the first switching circuit to cut off the connection between the laser transmitter and the energy storage circuit according to the first driving signal in the first time interval; the driving circuit is further used for controlling the first switching circuit to conduct the connection between the laser transmitter and the energy storage circuit according to the second driving signal in the second time interval.

Further, the power source charges the charging circuit for at least a portion of the duration of the second period.

Further, during the at least part of the duration of the second period, a first loop including the power supply, the charging circuit, and the first switch circuit connected in series with each other is turned on.

Further, during the second period, a second loop circuit including the tank circuit, the laser transmitter, and the first switch circuit connected in series with each other is turned on.

Further, the first loop also includes the laser transmitter.

Further, the laser transmitter is not located on the first loop.

Further, the light emitting device further includes a second switching circuit between the charging circuit and the tank circuit.

Further, the second switch circuit is located on the first loop and used for conducting the power supply, the charging circuit and the first switch circuit in the second time period.

Further, the second switch circuit is used for conducting the connection between the charging circuit and the energy storage circuit in the first time interval, and disconnecting the connection between the charging circuit and the energy storage circuit when the charging circuit completes energy storage of the energy storage circuit.

Further, the light emitting device further includes a third switching circuit between the charging circuit and the energy storage circuit.

Further, the third switch circuit is configured to disconnect the charging circuit and the tank circuit during the second period.

Further, the third switch circuit is used for conducting the charging circuit and the energy storage circuit in the first period, and the third switch circuit is switched off when the charging circuit finishes storing energy to the energy storage circuit.

Further, the third switch circuit is a third diode.

Further, the second switch circuit is a first diode.

Further, the laser transmitter includes a laser diode; the first end of the laser diode is connected with the energy storage circuit, and the second end of the laser diode is connected with the first end of the first switch circuit; the driving circuit is connected with the second end of the first switch circuit, wherein the driving circuit controls the first switch circuit; and the third end of the first switch circuit is connected with the ground.

Further, the charging circuit further comprises at least one resistor connected to the inductor for limiting the current of the charging circuit.

Further, the charging circuit further comprises a resistor, a voltage calibration source and a triode.

Furthermore, one end of a resistor in the current limiting circuit is connected to the power supply, and the other end of the resistor is connected to the voltage calibration source.

Furthermore, the first end of the triode is connected to the power supply, the second end of the triode is connected to the other end of the resistor of the current limiting circuit, and the third end of the triode is connected to the at least one capacitor.

Furthermore, a first end of the voltage calibration source is connected to a resistor in the current limiting circuit and a second end of the triode, a second end of the voltage calibration source is connected to an input end of the laser transmitter, and a third end of the voltage calibration source is connected to a third end of the triode.

Furthermore, one end of the at least one capacitor is connected to the charging circuit, and the other end of the at least one capacitor is grounded.

Further, the light emitting device further includes a second diode, one end of the second diode is connected to the charging circuit, and the other end is grounded.

Further, the light emitting device further comprises a voltage boosting circuit, and the voltage boosting circuit is used for boosting the input voltage to adapt to the requirements of different laser emitters.

In a second aspect, an embodiment of the present invention further provides a distance measuring apparatus, including: the light emitting device of the first aspect, configured to sequentially emit a laser pulse signal; the photoelectric conversion circuit is used for receiving at least part of optical signals reflected by an object from the laser pulse signals emitted by the light emitting device and converting the received optical signals into electric signals; the sampling circuit is used for sampling the electric signal from the photoelectric conversion circuit to obtain a sampling result; and the arithmetic circuit is used for calculating the distance between the object and the distance measuring device according to the sampling result.

Further, the number of the light emitting devices and the number of the photoelectric conversion circuits are respectively at least 2; each photoelectric conversion circuit is used for receiving at least part of optical signals reflected by the object from the laser pulse signals emitted by the corresponding light emitting device and converting the received optical signals into electric signals.

Further, the laser ranging device further comprises a scanning module; the scanning module is used for changing the transmission direction of the laser pulse signal and then emitting the laser pulse signal, and the laser pulse signal reflected back by the object enters the photoelectric conversion circuit after passing through the scanning module.

Furthermore, the scanning module comprises a driver and a prism with uneven thickness, and the driver is used for driving the prism to rotate so as to change the laser pulse signals passing through the prism to be emitted in different directions.

Furthermore, the scanning module comprises two drivers and two prisms which are arranged in parallel and have uneven thickness, and the two drivers are respectively used for driving the two prisms to rotate in opposite directions; and laser pulse signals from the laser emitting device sequentially pass through the two prisms and then change the transmission direction to be emitted.

In a third aspect, an embodiment of the present invention further provides a mobile platform, where the mobile platform includes any one of the light emitting devices described in the first aspect and a platform body, and the distance measuring device is installed on the platform body.

Further, the mobile platform includes at least one of an unmanned aerial vehicle, an automobile, and a remote control car.

The invention provides a laser emission scheme which accords with human eye safety regulations by providing the light emitting device, the distance measuring device and the mobile platform, and when a system has a single fault, a circuit in the device can ensure that a laser radiation value does not exceed a safety value, thereby ensuring the use safety of the laser device.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic view of a connection mode of a laser transmitter provided in the prior art;

fig. 2 is a schematic view of a first embodiment of a laser transmitter provided by the present invention;

FIG. 3 is a schematic diagram of a first embodiment of the present invention showing the path of an NMOS transistor during conduction;

FIG. 4 is a schematic diagram of a path of an NMOS transistor in a first embodiment of the present invention when it is turned off;

FIG. 5 is a schematic view of a second embodiment of a laser transmitter provided in the present invention;

FIG. 6 is a schematic view of an alternative to the second embodiment of the laser transmitter of the present invention;

FIG. 7 is a schematic diagram of a second embodiment of the present invention showing an NMOS transistor failing in short circuit;

FIG. 8 is a schematic diagram of the open failure of C1 in a second embodiment provided by the present invention;

FIG. 9 is a schematic illustration of a second embodiment of the present invention in the event of a C1 short failure;

FIG. 10 is a schematic diagram of D1 open circuit failure in a second embodiment provided by the present invention;

FIG. 11 is a schematic diagram of D1 short circuit failure in a second embodiment provided by the present invention;

FIG. 12 is a schematic diagram of an L1 open circuit failure in a second embodiment provided by the present invention;

FIG. 13 is a schematic diagram of L1 short circuit failure in a second embodiment provided by the present invention;

FIG. 14 is a schematic illustration of R1 open circuit failure in a second embodiment provided by the present invention;

FIG. 15 is a schematic illustration of R1 short circuit failure in a second embodiment of the present invention;

fig. 16 is a schematic view of a third embodiment of a laser transmitter provided by the present invention;

FIG. 17 is a schematic diagram of an inductor charging path when an NMOS transistor is turned on according to a third embodiment of the present invention;

FIG. 18 is a schematic diagram of a capacitor charging path when the NMOS transistor is turned off in the third embodiment of the present invention;

FIG. 19 is a schematic diagram illustrating the paths of the inductor charging and the capacitor discharging when the NMOS transistor is turned on according to the third embodiment of the present invention;

FIG. 20 is a schematic diagram of an NMOS transistor open circuit failure in a third embodiment of the present invention;

FIG. 21 is a schematic diagram of a third embodiment of the present invention showing an NMOS transistor short-circuit failure;

FIG. 22 is a schematic diagram of D2 open circuit failure in a third embodiment provided by the present invention;

FIG. 23 is a schematic diagram of D2 short circuit failure in a third embodiment provided by the present invention;

FIG. 24 is a schematic block diagram of a ranging apparatus provided in an embodiment of the present invention;

FIG. 25 is a schematic diagram of an embodiment of a distance measuring device using coaxial optical paths according to embodiments of the present invention;

FIG. 26 is a schematic view of a fourth embodiment provided by the present invention;

FIG. 27 is a schematic illustration of a fifth embodiment provided by the present invention;

FIG. 28 is a current flow diagram in a fifth embodiment provided by the present invention;

fig. 29 is a timing control diagram in the fifth embodiment provided by the present invention.

Description of the reference numerals

1 pulse laser diode 2 pulse signal 3 drive

4 boost circuit 5 current limiting circuit

100, 200 distance measuring device 201 detected object 202 scanning module

110 transmit circuit 103, 203 transmitter

120 receive circuit 104, 204 collimating element

130 sampling circuit 105, 205 detector

140 arithmetic circuit 206 optical path changing element 207 optical time-of-flight

150 control circuit 210 ranging module 209 axis

160, 202 scanning module 214 first optical element 215 second optical element

117, 216 drivers 119, 219 collimate the beam

211,213 light 212 back light 218 controller

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the existing solution adopts a light emitting device of a pulse driving design, which includes a power supply, a light source and a control circuit, wherein the power supply is VCC _ LD, the light source is a pulse laser diode, the control circuit includes a driving circuit and a switching circuit NMOS, when a pulse signal is at a high level, the driving circuit drives and outputs a high voltage and a large current, rapidly turns on an NMOS tube, a cathode of the pulse laser diode is grounded, an anode is connected to the power supply VCC _ LD, a voltage difference exists, the laser diode is turned on to emit light, when the pulse signal is at a low level, the NMOS tube is turned off, and thus the laser diode is also turned off. Therefore, by controlling the duty ratio and the frequency of the pulse signal, the duration and the frequency of the light emission of the laser diode can be controlled, and the radiation quantity of the laser diode can be further controlled.

Then for a particular laser diode selection, the luminous energy is determined by the following factors: (1) the light emitting duration of the single pulse laser diode correspondingly controls the duty ratio or pulse width of the pulse signal; (2) the working frequency of the laser diode in unit time corresponds to the frequency of the control pulse signal; (3) the peak power of the laser diode correspondingly controls the working voltage VCC _ LD. The duty ratio or the pulse width of the control pulse signal determines the length of the light emitting time of the single pulse laser diode, the larger the duty ratio or the pulse width is, the larger the light emitting energy is, and conversely, the smaller the duty ratio or the pulse width is, the smaller the light emitting energy is, the frequency of the control pulse signal determines the working frequency of the laser diode in unit time, the higher the signal frequency is, the larger the light emitting energy is, the lower the signal frequency is, the smaller the light emitting energy is, the control working voltage determines the peak power of the laser diode, the higher the control working voltage is, the larger the light emitting energy is, the lower the control working voltage is, and the smaller the light emitting energy is. However, this solution has the problem that if there is a single failure in the system, for example: (1) bug exists on software, and the pulse width of the pulse signal is too large; (2) the NMOS tube is failed and is directly short-circuited; (3) when the (1) th fault occurs, the pulse width is too large, so that the light emitting time of the laser diode is too long, the total radiant quantity exceeds a preset value and exceeds a specified value of human eye safety, when the (2) th fault occurs, the MOS tube fails, so that the laser diode is always in a light emitting state, the total radiant quantity exceeds the preset value and exceeds the specified value of human eye safety, and when the (3) th fault occurs, the power supply voltage is too high, so that the laser power is too large and exceeds the specified value of human eye safety, so that the laser diode can emit light with the radiant quantity or the light emitting power exceeding the specified value of human eye safety to hurt human eyes as long as one of the three conditions occurs.

The laser emitting device of the present invention includes: the laser power supply comprises a power supply, a laser transmitter, a charging circuit, an energy storage circuit and a control circuit, wherein the power supply is connected with the charging circuit and is used for charging the charging circuit for at least part of time; the energy storage circuit is respectively connected with the laser transmitter and the charging circuit, the energy storage circuit comprises at least one capacitor, and the charging circuit comprises at least one inductor; the control circuit is used for cutting off the connection between the laser transmitter and the energy storage circuit in a first time period, and the charging circuit is used for charging the energy storage circuit in at least part of the time period of the first time period; the control circuit is further used for conducting connection between the laser transmitter and the energy storage circuit in a second time interval, so that the energy storage circuit supplies power to the laser transmitter, the laser transmitter emits light pulse signals until the output current of the capacitor is lower than the threshold current of the laser transmitter; the first time period and the second time period alternate such that the laser emitter emits a sequence of laser pulses.

The power supply comprises a supply end of VCC _ HV and a booster circuit. The laser transmitter includes a laser diode. The charging circuit comprises an inductor, and in other alternative embodiments, the charging circuit comprises an inductor and a resistor, wherein the number of the inductors can be selected according to the condition of the system, and exemplarily, one inductor can be selected, and two or more inductors can also be selected. The energy storage circuit comprises capacitors, wherein the number of the capacitors can be selected according to the condition of the system, and exemplarily, one capacitor can be selected, and two or more capacitors can be selected. The control circuit, including transistors, may illustratively be selected from bipolar transistors or field effect transistors.

Wherein the power supply is connected to the charging circuit for charging the charging circuit for at least a portion of the duration; the energy storage circuit comprises a capacitor, and the capacitor is respectively connected with the laser transmitter and the charging circuit; the control circuit comprises a switching circuit, which comprises a transistor, which may be an NMOS or PMOS transistor, for example, and is used to disconnect the laser emitter from the energy storage circuit for a first period of time, that is, the transistor is in an off state, during at least a part of the first period of time, the charging circuit is used to charge the energy storage circuit, and when the transistor is in the off state, the inductor charges the capacitor, but the charging process is not always performed in the off state of the transistor, and the charging process may be performed only for a part of the period of time; the control circuit is further used for conducting connection between the laser transmitter and the energy storage circuit in a second time interval, so that the energy storage circuit supplies power to the laser transmitter, the laser transmitter emits light pulse signals until the output current of the capacitor is lower than the threshold current of the laser transmitter, namely the transistor is in a conducting state, in the second time interval, the laser diode is conducted with the capacitor, and the capacitor supplies power to the laser diode, so that the laser diode emits the light pulse signals; the first time interval and the second time interval are alternately carried out, so that the laser emitter emits a laser pulse sequence, the transistor is alternately switched off and switched on, no optical signal is emitted by the laser diode in the state that the transistor is switched off, and the optical pulse sequence is emitted by the laser diode in the state that the transistor is switched on and the optical pulse signal is emitted by the laser diode.

Exemplarily, a first embodiment of the present invention is shown in fig. 2, which shows a first structural schematic diagram of a laser emitting device, including a pulsed laser diode 1, a pulsed signal 2, a driver 3, a voltage boost circuit 4, a charging circuit, a tank circuit, a control circuit, and so on. The charging circuit comprises an inductor L1, the control circuit comprises a switch circuit, specifically an NMOS tube and a diode D1, and the energy storage circuit comprises a capacitor C1. In other embodiments, the switching circuit may be selected as another transistor, the diode D1 may be selected as a schottky diode, and the charging circuit may include more than two inductors, and the tank circuit may include more than two capacitors.

In the laser transmitter shown in fig. 2, the circuit operation of fig. 4 is described as follows with reference to fig. 3: 1) the initial state capacitor C1 is charged to be consistent with the power supply voltage VCC _ HV; 2) when the NMOS tube is conducted, the capacitor C1 discharges, the pulse laser diode emits light, at the moment, the D1 is conducted, and the inductor L1 is charged through a loop of the NMOS tube; as shown in fig. 3, when the NMOS transistor is turned on, the capacitor C1 discharges along the path shown in the figure, the pulsed laser diode correspondingly emits light, and since the NMOS transistor is in the on state, the first loop and the second loop are both in the on state, the first loop includes the power supply, the inductor L1, the diode D1, the pulsed laser diode and the NMOS transistor, and the second loop includes the capacitor C1, the pulsed laser diode and the NMOS transistor, when the NMOS transistor is turned on, the first loop is in the on state, so that the inductor L1 can be charged through the loop, and the second loop is also in the on state, and the capacitor C1 discharges through the path shown in fig. 3, so that the pulsed laser diode emits light; 3) when the NMOS tube is cut off, the current of the inductor L1 cannot change suddenly, so that the capacitor C1 is charged through the D1, and a charging process similar to boost is carried out; when the current of the inductor L1 is 0, the charging is finished, and the D1 is in an off state; referring to fig. 4 specifically, when the NMOS transistor is turned off, since the current of the inductor L1 cannot change abruptly, it is maintained at a relatively stable current level, the output current charges the capacitor C1 through the D1, the charging path is as the path shown in fig. 4, 4) repeats the processes of 2) and 3) in sequence, so that the laser diode emits a laser pulse sequence, each time step 2) is performed, the laser diode emits one laser pulse, and then the next step 2) is performed by charging with step 3).

In a first time interval, the NMOS tube is in a cut-off state, the step 1) is carried out in the first time interval, in a second time interval, the NMOS tube is in a conducting state, the step 2) is carried out, the capacitor supplies power to the laser diode to enable the laser diode to emit light, meanwhile, the power supply, the inductor, the diode, the laser diode and the switch circuit are also conducted, the power supply can charge the inductor, the first time interval and the second time interval are alternately carried out, then the first time interval is continued, the step 3) is carried out, the NMOS tube is in the cut-off state, the inductor charges the capacitor through the diode, when the current in the inductor is 0, the charging is finished, then the second time interval is continued, and the laser pulse sequence is emitted.

As can be seen from the first embodiment of the laser emitting device, the boosted voltage value can be controlled by controlling the output of the boost circuit 4, the conduction time of the inductor L1 and the NMOS transistor, and thus the charging energy of the capacitor can be controlled, and finally the light emitting energy of the pulsed laser diode can be controlled, and the light emitting energy of the laser diode depends on the charging energy of the capacitor. Therefore, under the condition that the power supply voltage VCC _ HV and the inductor L1 are not changed, the longer the NMOS transistor is turned on, the higher the voltage of the capacitor C1 is, the larger the charging energy is, and the higher the laser light emitting energy is. The light emitting energy is adjustable mainly to compensate individual difference, temperature change, aging attenuation difference and the like of devices, so that different laser diodes can output uniform laser pulses. In addition, since the inductor L1 stores energy when the NMOS transistor is turned on, the voltage of the capacitor C1 is higher than VCC _ HV after the capacitor C1 is charged by the inductor L1, and the effect of low-voltage input and high-voltage energy storage can be realized because the capacitor D1 is turned off in the reverse direction. Because the charging voltage of the capacitor C1 is higher, a capacitor with smaller capacitance value can be used, the discharging time is shorter, the light emitting time of the laser diode is shorter, and the pulse is narrower. Under the condition of unchanged luminous energy, the pulse is narrower, and a longer detection distance can be realized.

Optionally, in other embodiments of the first embodiment, the laser emitting device further comprises another diode, illustratively D2 shown in fig. 2, for grounding the L1, one end of which is connected to the inductor L1 and the other end of which is grounded.

Alternatively, the first embodiment includes a booster circuit between the power supply and the charging circuit. However, in other embodiments, the boosting circuit 4 may not be included, and the process of charging the inductor itself may be a boosting process, for example, and may be partially substituted for the boosting circuit.

Exemplarily, a second embodiment of the laser emitting device of the present invention is shown in fig. 5. Unlike the embodiment shown in fig. 2, in the embodiment shown in fig. 5, a current limiting circuit 5 is added to the charging circuit. When the NMOS transistor is accidentally shorted, the inductor L1 is equivalent to a conducting wire, and VCC _ HV directly excites the pulsed laser diode to emit light continuously, which may exceed the light emission energy specified by the safety of human eyes. Adding a current limiting circuit to the charging circuit can avoid this. In one example, the charging circuit and the current limiting circuit are arranged in series.

In one example, the current limiting circuit 5 includes at least one resistor. For example, as shown in fig. 5, the current limiting circuit includes resistors R1, R2. Optionally, resistors R1, R2 are arranged in series with the inductor L1. The operation of the circuit in the embodiment of fig. 5 corresponds to the operation of the circuit in the embodiment of fig. 2, wherein R1 and R2 can be directly replaced by a resistor. For another example, as shown in fig. 6, the current limiting circuit includes R1, R2, R3, R4, T1, and D4, where D4 is a voltage calibration source, T1 is a transistor, one end of a resistor R1 is connected to a power supply, the other end is connected to a common terminal of a first end of the voltage calibration source D4 and a second end of the transistor T1, one end of a resistor R2 is connected to the power supply, the other end is connected to a first end of the transistor T1, resistors R3 and R4 are connected in series, one end is connected to a third terminal of the transistor T1, the other end is connected to an inductor L1, the first end of the voltage calibration source D4 is connected to a common terminal of the resistor R1 and the second end of the transistor T1, the second end is connected to an inductor L1, and the third end is connected to a third terminal of the transistor T. The current limiting circuit in fig. 6 can better solve the problem that when an NMOS tube is accidentally shorted, the inductor L1 is equivalent to a lead, and then VCC _ HV directly excites the pulsed laser diode to continuously emit light, thereby exceeding the light-emitting energy specified by human eye safety, and ensuring the safety of the laser emitting device.

Referring to fig. 5, fig. 7-15 show that when a single failure occurs in the current limiting circuit implemented by resistors, the light emitting energy of the laser diode still does not exceed the specified value for human eye safety.

As shown in fig. 7, which shows that in the second embodiment shown in fig. 5, the NMOS transistor is failed and shorted, and the voltage dividing with the resistors R1 and R2 ensures that the voltage across the laser diode 1 is very small as long as the resistances of the resistors R1 and R2 are designed to be relatively large, and the current flowing through the laser diode 1 is smaller than the threshold current of light emission, so that the laser diode 1 is ensured not to continuously emit light, and the light emission energy of the laser diode is ensured not to exceed the specified value of human eye safety.

As shown in fig. 8, which shows that in the second embodiment shown in fig. 5, the energy storage circuit C1 fails to open, when the NMOS transistor is turned on, the resistances of the resistors R1 and R2 are designed, and the current flowing through the laser diode 1 is smaller than the threshold current of light emission, so that the light emission cannot be conducted, and the light emission energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As shown in fig. 9, which shows the second embodiment shown in fig. 5, the energy storage circuit C1 is short-circuited in failure, and both ends of the laser diode are GND, so that the laser diode cannot be turned on to emit light, thereby ensuring that the light-emitting energy of the laser diode does not exceed the specified value for human eye safety.

As shown in fig. 10, in the second embodiment shown in fig. 5, the diode D1 is failed to open, the energy storage capacitor C1 cannot be charged, and the laser diode cannot emit light, so that the light energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As shown in fig. 11, which shows that in the second embodiment shown in fig. 5, the diode D2 is failed and short-circuited, the charging voltage of the capacitor will be stabilized at VCC _ HV, and the stored energy will be reduced, so that the light-emitting energy will be reduced, and it can be ensured that the light-emitting energy of the laser diode will not exceed the specified value for human eye safety.

As shown in fig. 12, it is shown that in the second embodiment shown in fig. 5, the inductor L1 is opened, and the energy storage capacitor C1 cannot be charged, so that the laser diode cannot emit light, and the light-emitting energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As shown in fig. 13, which shows that in the second embodiment shown in fig. 5, the inductor L1 fails to short circuit, the charging voltage of the capacitor is not greater than VCC _ HV, the stored energy is reduced, and the light-emitting energy is reduced, so that the light-emitting energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As shown in fig. 14, in the second embodiment shown in fig. 5, a resistor R1 or R2 string is single fail open, and the energy storage capacitor C1 cannot be charged, so that the laser diode cannot emit light, and the light emitting energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As shown in fig. 15, in the second embodiment shown in fig. 5, the resistor R1 or R2 string is a single failure short circuit, so that the circuit can still work normally without affecting the light-emitting energy of the laser diode, and the light-emitting energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

It is worth noting that the resistor R1 is connected in series with the resistor R2, and the effect of single failure is consistent, so fig. 15 illustrates the problem with R1 as an example.

Optionally, in other embodiments of the second embodiment, the laser emitting device further includes another diode, for example, D2 shown in fig. 5 and fig. 6, for grounding the L1, one end of which is connected to the inductor L1, and the other end of which is grounded.

Alternatively, the second embodiment includes a booster circuit between the power supply and the charging circuit. However, in other embodiments, the boosting circuit 4 may not be included, and the process of charging the inductor itself may be a boosting process, for example, and may be partially substituted for the boosting circuit.

A third embodiment of the laser emitting device of the present invention is shown in fig. 16, and in the second embodiment of the laser emitting device, in order to ensure that the light emitting energy of the safety regulation is not exceeded when the single device fails, a current limiting circuit is introduced, but if a resistive device exists in the circuit, the energy is consumed, so that the energy efficiency of the whole laser emitting device is low. Therefore, the third embodiment of the laser transmitter is a further preferred embodiment, and the second embodiment is further improved, reducing the power consumption of the current limiting circuit.

In the laser transmitter shown in fig. 16, the circuit operation thereof will be described below with reference to fig. 17 to 19: in the initial state, the NMOS transistor is turned on, and the inductor L1 charges to store energy, which is shown in fig. 17 specifically, when the NMOS transistor is turned on, the power supply charges the inductor L1, and the charging path is shown in the path in fig. 17; when the NMOS transistor is turned off, the current of the inductor L1 cannot suddenly change, so that the capacitor C1 is charged through the D2, a charging process similar to boost is performed, when the current of the inductor L1 is 0, the charging is finished, and the D2 is turned off, as shown in fig. 18 specifically, when the NMOS transistor is turned off, the current cannot suddenly change due to the characteristic of the inductor L1, so that the capacitor C1 is charged through the diode D2, the charging process is similar to the boost process, as time goes on, the current of the current L1 is slowly reduced, when the current is reduced to 0, the charging is finished, and at this time, the D2 is turned off; when the NMOS transistor is turned on, the capacitor C1 discharges, the pulsed laser diode emits light, at this time, D1 is turned on, and the inductor L1 charges through the loop of the NMOS transistor, as shown in fig. 19, when the NMOS transistor is turned on, the capacitor C1 discharges along the illustrated path, the pulsed laser diode emits light accordingly, and since the NMOS transistor is in the on state, the first loop circuit is turned on and the second loop circuit is both in the on state, the first loop circuit includes the power supply, the inductor L1, the diode D1, and the NMOS transistor, the second loop circuit includes the capacitor C1, the pulsed laser diode, and the NMOS transistor, and when the NMOS transistor is turned on, the first loop circuit is in the on state, so that the inductor L1 can be charged through the loop circuit, and the second loop circuit is also in the on state, and the capacitor C1 discharges through the path illustrated in fig. 19, so that the pulsed laser diode; and (3) repeating the processes of 2) and 3) in sequence, so that the laser diode emits a laser pulse sequence, and executing the step 2) each time, and then charging by using the step 3) to ensure the execution of the next step 2).

As can be seen from the third embodiment of the laser emitting device, the boosted voltage value can be controlled by controlling the conduction time of the inductor L1 and the MOS transistor, and thus the charging energy of the capacitor can be controlled, and finally the light emitting energy of the pulsed laser diode can be controlled; under the condition that the supply voltage VCC and the inductor L1 are not changed, the longer the MOS tube conduction time is, the higher the voltage of the capacitor C1 is, the larger the charging energy is, and the higher the laser light-emitting energy is. The light emitting energy is adjustable mainly to compensate individual difference, temperature change, aging attenuation difference and the like of devices, so that different laser diodes can output uniform laser pulses.

In addition, since the inductor L1 stores energy when the MOS transistor is turned on, the voltage of the capacitor C1 is higher than VCC _ HV after the capacitor C1 is charged by the inductor L1, and the effects of low-voltage input and high-voltage energy storage can be achieved because the capacitors D1 and D2 are turned off in the opposite directions. A further advantage of the third embodiment is that a lower voltage input can be achieved, i.e., the voltage of VCC can be very low, similar to the effect of the second embodiment of the laser emitting device.

Referring to fig. 16, fig. 20-23 show that when a single failure occurs in the analyzing circuit, the light-emitting energy of the laser diode is still guaranteed not to exceed the specified value for human eye safety. Considering that a certain analysis has been made in the second embodiment, the effect of the failure is similar for the same components in the third embodiment, and therefore, we discuss the failure of only NMOS and D2 for the third embodiment of the laser emitting device.

As shown in fig. 20, it shows that in the third embodiment shown in fig. 16, the NMOS transistor fails to open, the laser diode and the capacitor cannot form a discharge circuit, and therefore the laser diode cannot emit light, so as to ensure that the light-emitting energy of the laser diode does not exceed the specified value for human eye safety.

As shown in fig. 21, it is shown that in the third embodiment shown in fig. 16, when the NMOS transistor fails and is shorted, the inductor L1 and the MOS transistor form a loop, which is always turned on and cannot store energy to the capacitor C1, so that the laser diode cannot emit light, and the light-emitting energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As shown in fig. 22, which shows that in the third embodiment shown in fig. 16, the diode D2 is open and the capacitor C1 cannot be charged to store energy, so that the laser diode cannot emit light, and the light-emitting energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As shown in fig. 23, which shows that in the third embodiment shown in fig. 16, the diode D2 is short-circuited, the discharge path of the capacitor C1 does not pass through the laser diode, so that the laser diode cannot emit light, and the light-emitting energy of the laser diode can be ensured not to exceed the specified value for human eye safety.

As the failure or short circuit of each element can not cause the output of the light emitting device to exceed the safety value, the circuit can effectively ensure that the output of the light emitting device conforms to the safety regulation of human eyes.

Optionally, in other embodiments of the third embodiment, the laser emitting device further includes another diode for grounding L1, one end of which is connected to the inductor L1, and the other end of which is grounded, and the diode for grounding the inductor is not shown in the corresponding drawings of the third embodiment.

Optionally, in other implementation manners of the second embodiment, the laser emitting device further includes a voltage boost circuit. Which is used for boosting the output of the power supply and has one end connected to the power supply and the other end connected to the inductor, the diode for boosting the output of the power supply is not shown in the figures corresponding to the third embodiment.

In the foregoing first embodiment, the second embodiment and the third embodiment, wherein the energy stored in the energy storage circuit has a preset upper limit value, it can be ensured that the light-emitting energy of the laser diode has the preset upper limit value, and further ensured that the radiation value of the laser diode does not exceed the safety value. Compared with the prior art, the light emitting device provided by the invention can achieve a laser emitting scheme meeting the human eye safety regulation, and when a system has a single fault, the circuit in the device can ensure that the laser radiation value does not exceed the safety regulation value, thereby ensuring the use safety of the laser device.

A fourth embodiment of the present invention is schematically shown in fig. 26, which shows a schematic structural diagram of a laser emitting apparatus, including a pulsed laser diode 1, a pulse signal 2, a charging circuit, a tank circuit, a control circuit, and the like. The charging circuit comprises an inductor L1, the control circuit comprises a switch circuit, specifically a PMOS tube Q1 and a diode D1, and the energy storage circuit comprises a capacitor C1. In other embodiments, the switching circuit may be selected as another transistor, the diode D1 may be selected as a schottky diode, and the charging circuit may include more than two inductors, and the tank circuit may include more than two capacitors.

In the laser emitting device shown in fig. 26, 1) the initial state capacitor C1 is charged to coincide with the power supply voltage; 2) when the PMOS tube is conducted, the capacitor C1 discharges, the pulse laser diode emits light, at the moment, the D1 is conducted, and the inductor L1 is charged through a loop of the PMOS tube; when the PMOS tube is conducted, the capacitor C1 discharges, the pulse laser diode correspondingly emits light, and because the PMOS tube is in a conducting state, the first loop circuit and the second loop circuit are both in a conducting state, the first loop circuit comprises a power supply, an inductor L1, a diode D1, the pulse laser diode and the PMOS tube, the second loop circuit comprises a capacitor C1, a pulse laser diode and a PMOS tube, when the PMOS tube is conducted, the first loop circuit is in a conducting state, therefore, the inductor L1 can be charged through the loop circuit, the second loop circuit is also in a conducting state, and the capacitor C1 discharges, so that the pulse laser diode emits light; 3) when the PMOS tube is cut off, the current of the inductor L1 cannot change suddenly, so that the capacitor C1 is charged through the D1; when the current of the inductor L1 is 0, the charging is finished, and the D1 is in an off state; 4) and (3) repeating the processes of 2) and 3) in sequence alternately, so that the laser diode emits a laser pulse sequence, and step 2) is executed each time, and then the laser diode emits one laser pulse, and then the next step 2) is executed by utilizing the step 3) for charging.

In the first time period, the PMOS tube is in a cut-off state, the step 1) is carried out in the first time period, in the second time period, the PMOS tube is in a conducting state, the step 2) is carried out, the capacitor supplies power to the laser diode to enable the laser diode to emit light, meanwhile, the power supply, the inductor, the diode, the laser diode and the switch circuit are also conducted, the power supply can charge the inductor, the first time period and the second time period are alternately carried out, then the first time period is continued, the step 3) is carried out, the PMOS tube is in the cut-off state, the inductor charges the capacitor through the diode, when the current in the inductor is 0, the charging is finished, then the second time period is continued, and the laser pulse sequence is emitted.

A fifth embodiment of the present invention is schematically shown in fig. 27, which shows a schematic diagram of a structure of a laser emitting apparatus, including a pulsed laser diode 1, a pulse signal 2, a charging circuit, a tank circuit, a control circuit, a reset circuit, and the like. The charging circuit comprises an inductor L1, the control circuit comprises a switch circuit, specifically a PMOS tube Q1 and a diode D1, the energy storage circuit comprises a capacitor C1, and the reset circuit comprises a switch circuit for resetting the voltage on the capacitor C1. In other embodiments, the switching circuit may be selected as another transistor, the diode D1 may be selected as a schottky diode, and the charging circuit may include more than two inductors, and the tank circuit may include more than two capacitors.

Fig. 28 is a current flow diagram in the fifth embodiment provided by the present invention, in which it is shown that in the laser transmitter shown in fig. 27, 1) the initial-state capacitance C1 is charged to coincide with the power supply voltage; 2) when the PMOS tube is conducted, the capacitor C1 discharges, the pulse laser diode emits light, at the moment, the D1 is conducted, and the inductor L1 is charged through a loop of the PMOS tube; when the PMOS tube is conducted, the capacitor C1 discharges, the pulse laser diode correspondingly emits light, and because the PMOS tube is in a conducting state, the first loop circuit and the second loop circuit are both in a conducting state, the first loop circuit comprises a power supply, an inductor L1, a diode D1 and the PMOS tube, the second loop circuit comprises a capacitor C1, the pulse laser diode and the PMOS tube, when the PMOS tube is conducted, the first loop circuit is in a conducting state, therefore, the inductor L1 can be charged through the loop circuit, the second loop circuit is also in a conducting state, and the capacitor C1 discharges to enable the pulse laser diode to emit light; 3) when the PMOS tube is cut off, the current of the inductor L1 cannot change suddenly, so that the capacitor C1 is charged through D1 and D2; when the current of the inductor L1 is 0, the charging is finished, and D1 and D2 are in a cut-off state; 4) and (3) repeating the processes of 2) and 3) in sequence alternately, so that the laser diode emits a laser pulse sequence, and step 2) is executed each time, and then the laser diode emits one laser pulse, and then the next step 2) is executed by utilizing the step 3) for charging.

Fig. 29 is a timing control diagram in a fifth embodiment of the present invention, in which a relationship between a control signal of a reset circuit and a control signal of the control circuit is shown, the reset circuit includes a switch circuit connected to both ends of a capacitor C1 for resetting a voltage across a capacitor C1. According to the time sequence control relationship, the reset circuit is reset once when the control circuit is opened once, namely, the reset circuit resets the voltage on the energy storage circuit, namely the capacitor C1 before and/or after the laser emitter emits light pulses, so that the finally obtained voltage on the capacitor can be controlled, the laser diode can be ensured not to exceed a preset value when the laser diode discharges, and the output of the laser diode is ensured not to exceed the safety value. The RESET circuit comprises a switch circuit RESET, which is connected to two ends of the capacitor C1 and is used for resetting the voltage on the capacitor C1, the signal of the RESET circuit is located inside the switch signal of the control circuit, when the control circuit opens the first switch circuit, the capacitor C1 discharges rapidly, the laser diode emits light pulses, namely, in the time period from t0 to t1, the pulse emits, at the time, the RESET circuit RESETs at t1, so that the voltage on the capacitor C1 is RESET, at the time, the RESET circuit RESETs the capacitor C1 after the laser transmitter emits the pulses, and the RESET is located before the next laser transmitter emits the light pulses, namely, before the time t3, the laser transmitter emits the next light pulses at the time t3, so that the RESET operation of the RESET circuit is located after the emission of the current light pulses and before the next light pulses are emitted.

The energy stored in the tank circuit has a preset upper limit, as shown in fig. 2 to 7, fig. 10, and C1 in the first to fifth embodiments shown in fig. 26 to 28.

The control circuit comprises a first switch circuit and a drive circuit connected with the first switch circuit; the driving circuit is used for controlling the first switching circuit to cut off the connection between the laser transmitter and the energy storage circuit according to the first driving signal in the first time interval; the driving circuit is further used for controlling the first switching circuit to conduct the connection between the laser transmitter and the energy storage circuit according to the second driving signal in the second time interval. The NMOS transistor in the first embodiment to the third embodiment, or the PMOS transistor in the fourth embodiment or the fifth embodiment.

Wherein the power supply charges the charging circuit for at least a portion of the duration of the second period, and the power supply charges the inductor L1 for at least a portion of the duration of the period, such as the period in which the control circuit is turned on in embodiments one through five. For example, see the charging path of fig. 3.

Wherein a first loop comprising the power supply, the charging circuit, and the first switching circuit connected in series with each other is turned on for the at least a portion of the duration of the second period. Exemplarily, in the first embodiment, as shown in fig. 3, the first loop includes a power supply, an inductor L1, and an NMOS transistor, and the loop constitutes the first loop. Illustratively, as shown in fig. 26, the first loop includes a power supply, an inductor L1, and a PMOS transistor, and the loop constitutes the first loop.

Wherein, in the second period, a second loop circuit including the tank circuit, the laser transmitter, and the first switch circuit connected in series with each other is turned on. Exemplarily, in the first embodiment, as shown in fig. 3, the second loop circuit includes the capacitor C1, the laser diode 1, and the NMOS transistor, and the loop circuit constitutes the second loop circuit. Illustratively, as shown in fig. 26, the second loop circuit includes a capacitor C1, a laser diode 1, and a PMOS transistor, and the loop circuit constitutes the second loop circuit.

Wherein the first loop further comprises the laser transmitter. Illustratively, as in the laser diode 1 of fig. 3 and 26.

Wherein the laser transmitter is not located on the first loop. Exemplarily, the laser diode 1 is not located on the first loop as in the embodiments shown in fig. 16 and 17.

Wherein the light emitting device further comprises a second switching circuit between the charging circuit and the tank circuit. Illustratively diode D1 as shown in fig. 3, and illustratively diode D1 as shown in fig. 26. Which all constitute a second switching circuit.

Wherein the second switch circuit is located on the first loop and is used for conducting the power supply, the charging circuit and the first switch circuit in the second period. Such as diode D1 shown in fig. 3, and illustratively, diode D1 shown in fig. 26. All located on the first loop for conducting the power supply, inductor L1 and the transistor switch.

The second switch circuit is used for conducting the connection between the charging circuit and the energy storage circuit in the first time interval, and disconnecting the connection between the charging circuit and the energy storage circuit when the charging circuit finishes storing energy to the energy storage circuit. Such as diode D1 shown in fig. 3, and illustratively, diode D1 shown in fig. 26. Which all constitute a second switching circuit for switching on the connection of the inductor L1 and the capacitor C1 during the first period, due to its unidirectional conduction, the connection of the inductor L1 and the capacitor C1 is disconnected after the energy storage of the capacitor C1 is completed.

Wherein the light emitting device further comprises a third switching circuit between the charging circuit and the energy storage circuit. Illustratively, diode D2 of the embodiment shown in fig. 16 and 17.

Wherein the third switch circuit is configured to disconnect the charging circuit and the tank circuit during the second period. Illustratively, diode D2 of the embodiment shown in fig. 16 and 17. Which each constitute a third switching circuit for disconnecting the inductance L1 and the capacitance C1 during the second period, which disconnects the connection during the second period due to its unidirectional conducting action.

The third switch circuit is used for conducting the charging circuit and the energy storage circuit in the first period, and is switched off when the charging circuit finishes storing energy for the energy storage circuit. Illustratively, diode D2 of the embodiment shown in fig. 16, 17 and 27. Which each constitute a third switch circuit for switching on the connection of the inductance L1 and the capacitance C1 during the first period, the connection of the inductance L1 and the capacitance C1 is disconnected after the energy storage of the capacitance C1 is completed, due to its unidirectional conduction.

Wherein the third switching circuit is a third diode. Illustratively, diode D2 of the embodiment shown in fig. 16, 17 and 27.

Wherein the second switch circuit is a first diode. Exemplarily, as the diode D1 in the first to fifth embodiments.

Wherein the laser transmitter comprises a laser diode; the first end of the laser diode is connected with the energy storage circuit, and the second end of the laser diode is connected with the first end of the first switch circuit; the driving circuit is connected with the second end of the first switch circuit, wherein the driving circuit controls the first switch circuit; and the third end of the first switch circuit is connected with the ground. Illustratively, in the first embodiment, the first terminal of the laser diode is connected to the inductor L1, the second terminal is connected to the driving circuit 3, the driving circuit 3 controls the NMOS transistor, and the NMOS transistor has a ground terminal.

Wherein the charging circuit further comprises at least one resistor connected to the inductor for limiting the current of the charging circuit. Illustratively, as in the first embodiment, R1 and R2 in fig. 5.

The charging circuit further comprises a resistor, a voltage calibration source and a triode. Illustratively, resistors R1-R4, a voltage calibration source, and a transistor T1 in fig. 6.

One end of a resistor in the current limiting circuit is connected to the power supply, and the other end of the resistor is connected to the voltage calibration source. Illustratively, resistor R1 in fig. 6 has one end connected to the power supply and the other end connected to the voltage calibration source and transistor T1.

The first end of the triode is connected with the power supply, the second end of the triode is connected with the other end of the resistor of the current limiting circuit, and the third end of the triode is connected with the at least one capacitor. Illustratively, in fig. 6, the transistor T1 has a first terminal connected to the power supply, a second terminal connected to the resistor R1, and a third terminal connected to the capacitor C1.

The first end of the voltage calibration source is connected to the resistor in the current limiting circuit and the second end of the triode, the second end of the voltage calibration source is connected to the input end of the laser transmitter, and the third end of the voltage calibration source is connected to the third end of the triode. Illustratively, as the voltage calibration source in fig. 6, the first terminal is connected to the resistor R1 and the second terminal of the transistor T1, the second terminal is connected to the input terminal of the laser diode 1, and the third terminal is connected to the third terminal of the transistor T1.

One end of the at least one capacitor is connected to the charging circuit, and the other end of the at least one capacitor is grounded. Illustratively, the capacitor C1 in the first to fifth embodiments has one end connected to the inductor L1 and the other end connected to ground.

The light emitting device further comprises a second diode, one end of the second diode is connected to the charging circuit, and the other end of the second diode is grounded. Illustratively, in the embodiment shown in fig. 2-14, one end of the second diode D2 is connected to the inductor L1, and the other end is connected to ground.

The light emitting device further comprises a boosting circuit, and the boosting circuit is used for boosting the input voltage to adapt to the requirements of different laser emitters. Illustratively, in the embodiments shown in fig. 2-14, a BOOST circuit BOOST is included for boosting the input voltage.

The circuit also comprises a reset circuit. Illustratively, as shown in fig. 27 and 28, a reset circuit is included.

The reset circuit comprises a switch circuit which is connected to two ends of the energy storage circuit and is used for resetting the voltage on the energy storage circuit. Illustratively, as shown in fig. 27 and 28, the RESET circuit includes a switch circuit RESET connected to two ends of the capacitor C1 for resetting the voltage on the capacitor C1.

Wherein the reset circuit resets the voltage on the tank circuit before and/or after the laser transmitter transmits a light pulse. Illustratively, as shown in fig. 29, the RESET circuit includes a switch circuit RESET, which is connected across the capacitor C1, for resetting the voltage on the capacitor C1, the signal of the reset circuit is located inside the switch signal of the control circuit, when the control circuit opens the first switching circuit, the capacitor C1 discharges rapidly, the laser diode emits a light pulse, i.e., during the time period t0 to t1, a pulse is sent out, at which time a reset is made at time t1, so that the voltage on the capacitor C1 is reset, at which time, after the laser transmitter emits a pulse, the capacitor C1 is reset, and this reset is preceded by the next laser transmitter pulse, i.e., prior to time t3, at time t3, the laser transmitter will begin transmitting the next light pulse, therefore, the reset operation of the reset circuit is located after this light pulse emission and before the next light pulse emission.

In another embodiment, the present invention further provides a distance measuring device, including any one of the light emitting devices described in the first aspect; the receiving circuit is used for receiving at least part of optical signals reflected by the object from the optical pulse signals emitted by the light emitting device and converting the received optical signals into electric signals; the sampling circuit is used for sampling the electric signal from the receiving circuit to obtain a sampling result; and the arithmetic circuit is used for calculating the distance between the object and the distance measuring device according to the sampling result. Further, the number of the light emitting devices is at least 2.

In another embodiment, an embodiment of the present invention further provides a mobile platform, where the mobile platform includes any one of the distance measuring devices described in the second aspect and a platform body, and the distance measuring device is installed on the platform body. Further, the mobile platform includes at least one of a manned vehicle, an unmanned vehicle, an automobile, a robot, and a remote control car.

The light emitting device provided by each embodiment of the invention can be applied to a distance measuring device, and the distance measuring device can be electronic equipment such as a laser radar, laser distance measuring equipment and the like. In one embodiment, the ranging device is used to sense external environmental information, such as distance information, orientation information, reflected intensity information, velocity information, etc. of environmental targets. In one implementation, the ranging device may detect the distance of the probe to the ranging device by measuring the Time of Flight (TOF), which is the Time-of-Flight Time, of light traveling between the ranging device and the probe. Alternatively, the distance measuring device may detect the distance from the probe to the distance measuring device by other techniques, such as a distance measuring method based on phase shift (phase shift) measurement or a distance measuring method based on frequency shift (frequency shift) measurement, which is not limited herein.

For ease of understanding, the following describes an example of the ranging operation with reference to the ranging apparatus 100 shown in fig. 24.

As shown in fig. 24, the ranging apparatus 100 may include a transmitting circuit 110, a receiving circuit 120, a sampling circuit 130, and an operation circuit 140.

The transmit circuitry 110 may transmit a sequence of light pulses (e.g., a sequence of laser pulses). The receiving circuit 120 may receive the optical pulse train reflected by the detected object, perform photoelectric conversion on the optical pulse train to obtain an electrical signal, process the electrical signal, and output the electrical signal to the sampling circuit 130. The sampling circuit 130 may sample the electrical signal to obtain a sampling result. The arithmetic circuit 140 may determine the distance between the distance measuring device 100 and the detected object based on the sampling result of the sampling circuit 130.

Optionally, the distance measuring apparatus 100 may further include a control circuit 150, and the control circuit 150 may implement control of other circuits, for example, may control an operating time of each circuit and/or perform parameter setting on each circuit, and the like.

It should be understood that, although the distance measuring device shown in fig. 24 includes a transmitting circuit, a receiving circuit, a sampling circuit and an arithmetic circuit for emitting a light beam to detect, the embodiment of the present application is not limited thereto, and the number of any one of the transmitting circuit, the receiving circuit, the sampling circuit and the arithmetic circuit may be at least two, and the at least two light beams are emitted in the same direction or in different directions respectively; the at least two light paths may be emitted simultaneously or at different times. In one example, the light emitting chips in the at least two transmitting circuits are packaged in the same module. For example, each transmitting circuit comprises a laser emitting chip, and die of the laser emitting chips in the at least two transmitting circuits are packaged together and accommodated in the same packaging space.

In some implementations, in addition to the circuit shown in fig. 24, the distance measuring apparatus 100 may further include a scanning module 160 for changing the propagation direction of at least one laser pulse sequence emitted from the emitting circuit.

Here, a module including the transmission circuit 110, the reception circuit 120, the sampling circuit 130, and the operation circuit 140, or a module including the transmission circuit 110, the reception circuit 120, the sampling circuit 130, the operation circuit 140, and the control circuit 150 may be referred to as a ranging module, which may be independent of other modules, for example, the scanning module 160.

The distance measuring device can adopt a coaxial light path, namely the light beam emitted by the distance measuring device and the reflected light beam share at least part of the light path in the distance measuring device. For example, at least one path of laser pulse sequence emitted by the emitting circuit is emitted by the scanning module after the propagation direction is changed, and the laser pulse sequence reflected by the detector is emitted to the receiving circuit after passing through the scanning module. Alternatively, the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance measuring device and the reflected light beam are transmitted along different optical paths in the distance measuring device. FIG. 25 shows a schematic diagram of one embodiment of a distance measuring device of the present invention employing coaxial optical paths.

The ranging apparatus 200 comprises a ranging module 210, the ranging module 210 comprising an emitter 203 (which may comprise the transmitting circuitry described above), a collimating element 204, a detector 205 (which may comprise the receiving circuitry, sampling circuitry and arithmetic circuitry described above) and a path-altering element 206. The distance measuring module 210 is configured to emit a light beam, receive return light, and convert the return light into an electrical signal. Wherein the emitter 203 may be configured to emit a sequence of light pulses. In one embodiment, the transmitter 203 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the emitter 203 is a narrow bandwidth beam having a wavelength outside the visible range. The collimating element 204 is disposed on an emitting light path of the emitter, and is configured to collimate the light beam emitted from the emitter 203, and collimate the light beam emitted from the emitter 203 into parallel light to be emitted to the scanning module. The collimating element is also for converging at least a portion of the return light reflected by the detector. The collimating element 204 may be a collimating lens or other element capable of collimating a light beam.

In the embodiment shown in fig. 25, the transmit and receive optical paths within the distance measuring device are combined by the optical path changing element 206 before the collimating element 104, so that the transmit and receive optical paths can share the same collimating element, making the optical path more compact. In other implementations, the emitter 103 and the detector 105 may use respective collimating elements, and the optical path changing element 206 may be disposed in the optical path after the collimating elements.

In the embodiment shown in fig. 25, since the beam aperture of the light beam emitted from the emitter 103 is small and the beam aperture of the return light received by the distance measuring device is large, the optical path changing element can adopt a small-area mirror to combine the emission optical path and the reception optical path. In other implementations, the optical path changing element may also be a mirror with a through hole, wherein the through hole is used for transmitting the outgoing light from the emitter 203, and the mirror is used for reflecting the return light to the detector 205. Therefore, the shielding of the bracket of the small reflector to the return light can be reduced in the case of adopting the small reflector.

In the embodiment shown in fig. 25, the optical path changing element is offset from the optical axis of the collimating element 204. In other implementations, the optical path altering element may also be located on the optical axis of the collimating element 204.

The ranging device 200 also includes a scanning module 202. The scanning module 202 is disposed on the outgoing light path of the distance measuring module 210, and the scanning module 102 is configured to change the transmission direction of the collimated light beam 219 emitted by the collimating element 204, project the collimated light beam to the external environment, and project the return light beam to the collimating element 204. The return light is converged by the collimating element 104 onto the detector 105.

In one embodiment, the scanning module 202 may include at least one optical element for altering the propagation path of the light beam, wherein the optical element may alter the propagation path of the light beam by reflecting, refracting, diffracting, etc., the light beam. For example, the scanning module 202 includes a lens, mirror, prism, galvanometer, grating, liquid crystal, Optical Phased Array (Optical Phased Array), or any combination thereof. In one example, at least a portion of the optical element is moved, for example, by a driving module, and the moved optical element can reflect, refract, or diffract the light beam to different directions at different times. In some embodiments, multiple optical elements of the scanning module 202 may rotate or oscillate about a common axis 209, with each rotating or oscillating optical element serving to constantly change the direction of propagation of an incident beam. In one embodiment, the multiple optical elements of the scanning module 202 may rotate at different rotational speeds or oscillate at different speeds. In another embodiment, at least some of the optical elements of the scanning module 202 may rotate at substantially the same rotational speed. In some embodiments, the multiple optical elements of the scanning module may also be rotated about different axes. In some embodiments, the multiple optical elements of the scanning module may also rotate in the same direction, or in different directions; or in the same direction, or in different directions, without limitation.

In one embodiment, the scanning module 202 includes a first optical element 214 and a driver 216 coupled to the first optical element 214, the driver 216 configured to drive the first optical element 214 to rotate about the rotation axis 209, such that the first optical element 214 redirects the collimated light beam 219. The first optical element 214 projects the collimated light beam 219 into different directions. In one embodiment, the angle between the direction of the collimated beam 219 after it is altered by the first optical element and the rotational axis 109 changes as the first optical element 214 is rotated. In one embodiment, the first optical element 214 includes a pair of opposing non-parallel surfaces through which the collimated light beam 219 passes. In one embodiment, the first optical element 214 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, the first optical element 114 comprises a wedge prism that refracts the collimated beam 119.

In one embodiment, the scanning module 202 further comprises a second optical element 215, the second optical element 215 rotating around a rotation axis 209, the rotation speed of the second optical element 215 being different from the rotation speed of the first optical element 214. The second optical element 215 is used to change the direction of the light beam projected by the first optical element 214. In one embodiment, the second optical element 115 is coupled to another driver 217, and the driver 117 drives the second optical element 215 to rotate. The first optical element 214 and the second optical element 215 may be driven by the same or different drivers, such that the first optical element 214 and the second optical element 215 rotate at different speeds and/or turns, thereby projecting the collimated light beam 219 into different directions in the ambient space, which may scan a larger spatial range. In one embodiment, the controller 218 controls the

drivers

216 and 217 to drive the first optical element 214 and the second optical element 215, respectively. The rotation speed of the first optical element 214 and the second optical element 215 can be determined according to the region and the pattern expected to be scanned in the actual application. The

drives

216 and 217 may include motors or other drives.

In one embodiment, the second optical element 115 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, second optical element 115 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, second optical element 115 comprises a wedge angle prism.

In one embodiment, the scan module 102 further comprises a third optical element (not shown) and a driver for driving the third optical element to move. Optionally, the third optical element comprises a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element comprises a prism having a thickness that varies along at least one radial direction. In one embodiment, the third optical element comprises a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or rotational directions.

Rotation of the optical elements in the scanning module 202 may project light in different directions, such as the directions of

light

211 and 213, thus scanning the space around the ranging device 200. When the light 211 projected by the scanning module 202 hits the detected object 201, a part of the light is reflected by the detected object 201 to the distance measuring device 200 in the direction opposite to the projected light 211. The return light 212 reflected by the detected object 201 passes through the scanning module 202 and then enters the collimating element 204.

The detector 205 is placed on the same side of the collimating element 204 as the emitter 203, and the detector 205 is used to convert at least part of the return light passing through the collimating element 204 into an electrical signal.

In one embodiment, each optical element is coated with an antireflection coating. Optionally, the thickness of the antireflection film is equal to or close to the wavelength of the light beam emitted by the emitter 103, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is coated on a surface of a component in the distance measuring device, which is located on the light beam propagation path, or a filter is arranged on the light beam propagation path, and is used for transmitting at least a wave band in which the light beam emitted by the emitter is located and reflecting other wave bands, so as to reduce noise brought to the receiver by ambient light.

In some embodiments, the transmitter 203 may include a laser diode through which laser pulses in the order of nanoseconds are emitted. Further, the laser pulse reception time may be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this manner, the ranging apparatus 200 can calculate TOF using the pulse reception time information and the pulse emission time information, thereby determining the distance of the object 201 to be detected to the ranging apparatus 200.

The distance and orientation detected by ranging device 200 may be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like. In an embodiment, the distance measuring device of the embodiment of the invention can be applied to a mobile platform, and the distance measuring device can be installed on a platform body of the mobile platform. The mobile platform with the distance measuring device can measure the external environment, for example, the distance between the mobile platform and an obstacle is measured for the purpose of avoiding the obstacle, and the external environment is mapped in two dimensions or three dimensions. In certain embodiments, the mobile platform comprises at least one of an unmanned aerial vehicle, an automobile, a remote control car, a robot, a camera. When the distance measuring device is applied to the unmanned aerial vehicle, the platform body is a fuselage of the unmanned aerial vehicle. When the distance measuring device is applied to an automobile, the platform body is the automobile body of the automobile. The vehicle may be an autonomous vehicle or a semi-autonomous vehicle, without limitation. When the distance measuring device is applied to the remote control car, the platform body is the car body of the remote control car. When the distance measuring device is applied to a robot, the platform body is the robot. When the distance measuring device is applied to a camera, the platform body is the camera itself.

Technical terms used in the embodiments of the present invention are only used for illustrating specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the use of "including" and/or "comprising" in the specification is intended to specify the presence of stated features, integers, steps, operations, elements, and/or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below, if any, are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. The embodiments described herein are further intended to explain the principles of the invention and its practical application and to enable others skilled in the art to understand the invention.

The flow chart described in the present invention is only an example, and various modifications can be made to the diagram or the steps in the present invention without departing from the spirit of the present invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted or modified. It will be understood by those skilled in the art that all or a portion of the above-described embodiments may be practiced and equivalents thereof may be resorted to as falling within the scope of the invention as claimed.

Claims

A light emitting device, comprising: the laser power supply comprises a power supply, a laser transmitter, a charging circuit, an energy storage circuit and a control circuit, wherein the power supply is connected with the charging circuit and is used for charging the charging circuit for at least part of time;

the energy storage circuit is respectively connected with the laser transmitter and the charging circuit, the energy storage circuit comprises at least one capacitor, and the charging circuit comprises at least one inductor;

the control circuit is used for cutting off the connection between the laser transmitter and the energy storage circuit in a first time period, and the charging circuit is used for charging the energy storage circuit in at least part of the time period of the first time period;

the control circuit is further used for conducting connection between the laser transmitter and the energy storage circuit in a second time interval, so that the energy storage circuit supplies power to the laser transmitter, the laser transmitter emits light pulse signals until the output current of the capacitor is lower than the threshold current of the laser transmitter;

the first time period and the second time period alternate such that the laser emitter emits a sequence of laser pulses.
The light emitting device of claim 1, wherein the energy stored by the tank circuit has a preset upper limit.
The light-emitting device according to claim 1, wherein the control circuit includes a first switch circuit, and a drive circuit connected to the first switch circuit;

the driving circuit is used for controlling the first switching circuit to cut off the connection between the laser transmitter and the energy storage circuit according to the first driving signal in the first time interval;

the driving circuit is further used for controlling the first switching circuit to conduct the connection between the laser transmitter and the energy storage circuit according to the second driving signal in the second time interval.
The light emitting device of claim 3, wherein the power source charges the charging circuit for at least a portion of the duration of the second period of time.
The light emitting device according to claim 4, wherein a first loop circuit including the power supply, the charging circuit, and the first switch circuit connected in series with each other is turned on for the at least part of the duration of the second period.
The light emitting device according to claim 4 or 5, wherein a second loop circuit including the tank circuit, the laser transmitter, and the first switch circuit connected in series with each other is turned on in the second period.
The light emitting apparatus of claim 5, wherein the first loop further comprises the laser emitter.
The light emitting device of claim 5, wherein the laser emitter is not located on the first loop.
The light emitting device according to any one of claims 3-5, 7, and 8, further comprising a second switching circuit between the charging circuit and the tank circuit.
The light emitting device according to claim 9, wherein the second switch circuit is provided on the first loop circuit to turn on the power supply, the charging circuit and the first switch circuit during the second period.
The light emitting device according to claim 9, wherein the second switch circuit is configured to turn on the connection between the charging circuit and the energy storage circuit during the first period, and turn off the connection between the charging circuit and the energy storage circuit when the charging circuit completes energy storage of the energy storage circuit.
The light emitting device according to any one of claims 1 to 5, 7, 8, 10 and 11, further comprising a third switching circuit between the charging circuit and the energy storage circuit.
The light emitting device according to claim 12, wherein the third switch circuit is configured to disconnect the charging circuit and the tank circuit during the second period.
The light emitting device according to claim 12, wherein the third switch circuit is configured to turn on the charging circuit and the energy storage circuit during the first period, and turn off the third switch circuit when the charging circuit completes storing energy in the energy storage circuit.
The light-emitting device according to claim 13 or 14, wherein the third switch circuit is a third diode.
The light-emitting device according to any one of claims 9, wherein the second switch circuit is a first diode.
The light-emitting device of claim 3, wherein the laser emitter comprises a laser diode;

the first end of the laser diode is connected with the energy storage circuit, and the second end of the laser diode is connected with the first end of the first switch circuit;

the driving circuit is connected with the second end of the first switch circuit, wherein the driving circuit controls the first switch circuit;

and the third end of the first switch circuit is connected with the ground.
The light emitting device of claim 1, wherein the charging circuit further comprises at least one resistor coupled to the inductor for limiting a current of the charging circuit.
The light emitting device of claim 18, wherein the charging circuit further comprises a resistor, a voltage calibration source, and a transistor.
The light emitting device of claim 19, wherein the resistor in the current limiting circuit has one end connected to the power supply and another end connected to the voltage calibration source.
The light emitting device of claim 19, wherein the transistor has a first terminal coupled to the power supply, a second terminal coupled to the other terminal of the resistor of the current limiting circuit, and a third terminal coupled to the at least one capacitor.
The light emitting device of claim 19, wherein the voltage calibration source has a first terminal coupled to a resistor in the current limiting circuit and a second terminal of the transistor, a second terminal coupled to the input of the laser emitter, and a third terminal coupled to a third terminal of the transistor.
The light emitting device according to claim 1, wherein one end of the at least one capacitor is connected to the charging circuit, and the other end is grounded.
The light emitting device according to claim 1, further comprising a second diode, one end of the second diode being connected to the charging circuit and the other end being grounded.
The light emitting device of claim 1, further comprising a voltage boost circuit for boosting an input voltage to accommodate different requirements of the laser emitter.
The light emitting device according to claim 1, further comprising a reset circuit.
The light emitting device of claim 26, wherein the reset circuit comprises a switching circuit coupled across the tank circuit for resetting the voltage across the tank circuit.
A light emitting device according to claim 26 or 27, wherein the reset circuit resets the voltage across the tank circuit before and/or after a light pulse is emitted by the laser emitter.
A ranging apparatus, comprising:

the light emitting device according to any one of claims 1 to 28, for sequentially emitting laser pulse signals;

the photoelectric conversion circuit is used for receiving at least part of optical signals reflected by an object from the laser pulse signals emitted by the light emitting device and converting the received optical signals into electric signals;

the sampling circuit is used for sampling the electric signal from the photoelectric conversion circuit to obtain a sampling result;

and the arithmetic circuit is used for calculating the distance between the object and the distance measuring device according to the sampling result.
The ranging apparatus as claimed in claim 29, wherein the number of the light emitting means and the number of the photoelectric conversion circuits are at least 2, respectively;

each photoelectric conversion circuit is used for receiving at least part of optical signals reflected by the object from the laser pulse signals emitted by the corresponding light emitting device and converting the received optical signals into electric signals.
A ranging device as claimed in claim 29 or 30 wherein the laser ranging device further comprises a scanning module;

the scanning module is used for changing the transmission direction of the laser pulse signal and then emitting the laser pulse signal, and the laser pulse signal reflected back by the object enters the photoelectric conversion circuit after passing through the scanning module.
The range finder device of claim 31, wherein the scanning module comprises a driver and a prism with non-uniform thickness, and the driver is configured to rotate the prism to change the laser pulse signal passing through the prism to exit in different directions.
A ranging device as claimed in claim 32 wherein the scanning module comprises two drivers and two prisms of non-uniform thickness arranged in parallel, the two drivers being respectively used for driving the two prisms to rotate in opposite directions;

and laser pulse signals from the laser emitting device sequentially pass through the two prisms and then change the transmission direction to be emitted.
A mobile platform, comprising:

a ranging apparatus as claimed in any of claims 29 to 33; and

the platform body, range unit's light emitting device installs on the platform body.
The mobile platform of claim 34, wherein the mobile platform comprises at least one of an unmanned aerial vehicle, an automobile, and a robot.