A 3D structured light projector and a 3D structured light module

Abstract

The present invention discloses a 3D structured light projector and a 3D structured light module, the 3D structured light projector includes a power supply conversion module, a bucket-type energy storage module, a constant current drive control module and a laser projection module; the power supply conversion module is used to perform a voltage boost process on an external voltage input signal; the bucket-type energy storage module is used to store electric energy when the power supply conversion module is discharged, and release the electric energy to the constant current drive control module when the power supply conversion module is charged; by controlling the charging and discharging frequency of the power supply conversion module, a constant voltage boost output signal is provided to the constant current drive control module; the constant current drive control module is used to perform a constant current process on the constant voltage boost output signal, obtain a constant current output signal, and provide it to the laser projection module. The projector reduces the power supply demand of the laser projection module for the external voltage, improves the output peak optical power of the laser projection module, makes the scattered spot energy projected on the target object higher, and improves the outdoor depth test performance.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of three-dimensional imaging technology, and in particular to a 3D structured light projector and a 3D structured light module. Background Art

[0002] 3D structured light technology is widely used in face payment, indoor service robots and other fields due to its high precision and strong anti-counterfeiting performance. The 3D structured light module includes a structured light projector and an infrared receiving camera. The structured light projector projects a speckle with a certain characteristic pattern onto the target object. The speckle pattern reflected by the target object is collected by the infrared receiving camera, and the depth information of the target object can be calculated based on the principle of triangulation.

[0003] However, due to the limitations of the driving power supply and light source power, the existing structured light projector has a relatively small projected light power, generally less than 2W. When used outdoors, when the sunlight is strong, especially in scenes with a long measurement distance, such as scenes greater than 0.5m, the speckle in the collected infrared image is basically annihilated in the background light, resulting in inaccurate depth value measurement, and in severe cases, the depth value cannot be calculated. This also makes it impossible to apply 3D structured light modules to some common outdoor application scenarios, such as lawn mowers, outdoor robots, etc., limiting the application areas of structured light. Therefore, how to solve the integrity and accuracy of 3D structured light module imaging under strong outdoor light is a major problem currently faced. Summary of the invention

[0004] The embodiments of the present invention provide a 3D structured light projector and a 3D structured light module, which process the external voltage to obtain a stable high-amplitude constant current, effectively improve the output peak light power of the laser projection module, make the scattered light energy projected on the target object higher, and effectively improve the outdoor depth test performance.

[0005] In a first aspect, an embodiment of the present invention provides a 3D structured light projector, including a power supply conversion module, a bucket-type energy storage module, a constant current drive control module and a laser projection module;

[0006] The power supply conversion module is used to perform voltage boost processing on the external voltage input signal;

[0007] The bucket-type energy storage module is electrically connected to the power supply conversion module and the constant current drive control module respectively. The bucket-type energy storage module is used to store electric energy when the power supply conversion module is discharged, and release electric energy to the constant current drive control module when the power supply conversion module is charged; by controlling the charging and discharging frequency of the power supply conversion module, a constant boost output signal is provided to the constant current drive control module; wherein the bucket-type energy storage module includes a first capacitor, and the capacitance range of the first capacitor is 1500-5000 μF;

[0008] The constant current drive control module is electrically connected to the laser projection module, and is used to perform constant current processing on the constant boost output signal to obtain a constant current output signal, and provide the constant current output signal to the laser projection module; wherein the constant current output signal includes a pulse form and a DC form;

[0009] The laser projection module is used to project a structured light spot pattern onto a target object.

[0010] In a second aspect, an embodiment of the present invention further provides a 3D structured light module, comprising an infrared receiving camera and a 3D structured light projector as described in any one of the first aspects.

[0011] The embodiment of the present invention provides a 3D structured light projector and a 3D structured light module, which includes a power supply conversion module, a bucket-type energy storage module, a constant current drive control module and a laser projection module; the power supply conversion module is used to boost the external voltage input signal; the bucket-type energy storage module is electrically connected to the power supply conversion module and the constant current drive control module respectively, and the bucket-type energy storage module is used to store electric energy when the power supply conversion module is discharged, and release the electric energy to the constant current drive control module when the power supply conversion module is charged; by controlling the charging and discharging frequency of the power supply conversion module, a constant boost output signal is provided to the constant current drive control module; wherein, the bucket-type energy storage module includes a first capacitor, and the capacitance range of the first capacitor is 1500-5000μF; the constant current drive control module is electrically connected to the laser projection module, and the constant current drive control module is used to perform constant current processing on the constant boost output signal, obtain a constant current output signal, and provide it to the laser projection module; wherein, the constant current output signal includes a pulse form and a DC form; the laser projection module is used to project a structured light spot pattern onto a target object. The 3D structured light projector uses a power supply conversion module and a bucket-type energy storage module to process the external voltage, and provides a constant boost output signal to a constant current drive control module. The constant current drive control module performs constant current processing on the constant boost output signal to obtain a stable high-amplitude constant current, supporting the pulse power supply with a pulse width of hundreds of microseconds to milliseconds required by the laser projection module, effectively reducing the laser projection module's demand for external voltage. The external voltage can choose to use a universal USB power supply, which can convert the conventional power supply input with a voltage of 5V and a current of less than 1A into a large current constant current power supply output with an adjustable current range of 0-20A, which is then provided to the laser projection module, thereby increasing the output peak light power of the laser projection module, making the scattered spot energy projected on the target object higher, and improving the outdoor depth test performance to facilitate adaptation to more application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1is a schematic structural diagram of a 3D structured light projector provided by an embodiment of the present invention;

[0013] Figure 2 It is a schematic diagram of the circuit structure of a power supply conversion module and a bucket-type energy storage module provided in an embodiment of the present invention;

[0014] Figure 3 It is a circuit structure diagram of a constant current drive control module and a laser projection module provided by an embodiment of the present invention;

[0015] Figure 4 is a structural schematic diagram of a laser projection module provided by an embodiment of the present invention;

[0016] Figure 5 is a schematic diagram of the cross-sectional structure of a planar array laser provided by an embodiment of the present invention;

[0017] Figure 6 This is a schematic diagram of the spot distribution of a planar array laser in combination with an optical element module provided by an embodiment of the present invention;

[0018] Figure 7 is a schematic diagram of light spot distribution of another area array laser equipped with an optical element module provided by an embodiment of the present invention;

[0019] Figure 8 is a structural schematic diagram of an optical collimation unit provided by an embodiment of the present invention;

[0020] Fig. 9 yes Figure 8 Schematic diagram of distortion parameters of the optical collimation element shown;

[0021] Fig.10 yes Figure 8 The schematic diagram of the scattered spot size of the optical collimator at various image heights at 1m is shown;

[0022] Fig.11 yes Figure 8 A schematic diagram of relative illumination of the optical collimation element shown;

[0023] Fig.12 This is a schematic diagram of spot distribution of another planar array laser in combination with an optical element module provided by an embodiment of the present invention;

[0024] Fig.13 is a schematic structural diagram of another 3D structured light projector provided by an embodiment of the present invention;

[0025] Fig.14 yes Fig.13 A schematic diagram of the spatial distribution of the light spot area projected by the 3D structured light projector is shown;

[0026] Fig.15 yes Fig.13 Another schematic diagram of the spatial distribution of the light spot area projected by the 3D structured light projector is shown. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0028] Figure 1 is a schematic diagram of a 3D structured light projector provided by an embodiment of the present invention. Figure 1 As shown, the 3D structured light projector includes a power supply conversion module 10, a bucket-type energy storage module 20, a constant current drive control module 30 and a laser projection module 40; the power supply conversion module 10 is used to boost the external voltage input signal; the bucket-type energy storage module 20 is electrically connected to the power supply conversion module 10 and the constant current drive control module 30 respectively, and the bucket-type energy storage module 20 is used to store electric energy when the power supply conversion module 10 is discharged, and release electric energy to the constant current drive control module 30 when the power supply conversion module 10 is charged; by controlling the charging and discharging frequency of the power supply conversion module 10, A constant boost output signal is provided to the constant current drive control module 30; wherein, the bucket-type energy storage module 20 includes a first capacitor C1, and the capacitance range of the first capacitor C1 is 1500-5000μF; the constant current drive control module 30 is electrically connected to the laser projection module 40, and the constant current drive control module 30 is used to perform constant current processing on the constant boost output signal to obtain a constant current output signal, and provide it to the laser projection module 40; wherein, the constant current output signal includes a pulse form and a DC form; the laser projection module 40 is used to project a structural light spot pattern onto the target object.

[0029] First of all, it should be noted that 3D structured light projectors are generally used in low-power electronic devices or portable devices. Due to the power supply limitation of the device, the external voltage input signal is generally a conventional signal with a voltage of 5V, a current of less than 2A, and a power of less than 10W. The external voltage input signal can be converted into a constant current signal of less than 2A by a constant current drive chip. If the constant current signal of less than 2A is directly provided to the laser projection module 40, the projected light power of the laser projection module 40 will be relatively small, generally less than 2W, which is not conducive to the calculation of the depth value and the integrity and accuracy of the imaging. That is, the external voltage input signal cannot meet the power supply requirements of the laser projection module 40. Therefore, based on the above technical problems, the present embodiment sets a power supply conversion module 10, a bucket-type energy storage module 20 and a constant current drive control module 30 to pre-process the external voltage input signal, and then provide it to the laser projection module 40. In this way, the amplitude and stability of the constant current output signal output to the laser projection module 40 can be effectively improved, thereby increasing the output peak light power of the laser projection module 40.

[0030] Specifically, the 3D structured light projector includes a power conversion module 10, a bucket-type energy storage module 20, a constant current drive control module 30 and a laser projection module 40. Among them, the power conversion module 10 can boost the external voltage input signal to obtain a boosted output signal. Exemplarily, the external voltage input signal can be output by a constant voltage source that provides lower voltage and current, and the external voltage input signal can be output by a conventional USB power supply. Exemplarily, the external voltage input signal can be a conventional input with a voltage of 5V, a current of <2A, and a power of <10W. In other words, one end of the power conversion module 10 can receive the external voltage input signal, the power conversion module 10 can convert the external voltage input signal into a voltage signal with a higher amplitude for output, and the other end of the power conversion module 10 can output the corresponding boosted output signal. Exemplarily, the amplitude of the boosted output signal can be 1.4-12 times the amplitude of the external voltage input signal. In this way, the setting of the power conversion module 10 can effectively reduce the power supply demand of the laser projection module 40 for the external voltage. The external voltage can be powered by a universal USB, which can be adapted to more application scenarios.

[0031] The bucket-type energy storage module 20 is electrically connected to the power conversion module 10. The bucket-type energy storage module 20 can store electric energy when the power conversion module 10 is discharged, and release electric energy to the constant current drive control module 30 when the power conversion module 10 is charged. The bucket-type energy storage module 20 can output a constant boost output signal to ensure the normal operation of the constant current drive control module 30 and the conversion of the constant current output signal. In this embodiment, the process of converting the external voltage input signal in the power conversion module 10 into a boost output signal can be understood as a charging process, and the process of transmitting the boost output signal converted by the power conversion module 10 to the bucket-type energy storage module 20 can be understood as a discharging process. In addition, during the charging and discharging process of the power conversion module 10, the final boost output signal can be adjusted to be constant by reasonably controlling the charging and discharging frequency of the power conversion module 10, that is, providing a constant boost output signal for the constant current drive control module 30. In addition, the bucket-type energy storage module 20 can also store and filter the received boost output signal to ensure that the bucket-type energy storage module 20 itself outputs a constant boost output signal, which is then transmitted to the constant current drive control module 30. Exemplarily, the bucket-type energy storage module 20 can adopt a large-capacity energy storage circuit such as capacitor energy storage. Optionally, the bucket-type energy storage module 20 includes a first capacitor C1, which can achieve the function of large-capacity energy storage. The first capacitor C1 can release a power electrical signal of up to 14W for the constant current drive control module 30 for a long time, and the first capacitor C1 can also smooth the fluctuation of the constant voltage output signal and reduce ripple. Among them, the capacitance range of the first capacitor C1 is 1500-5000μF. Exemplarily, the ideal value of the capacitance of the first capacitor C1 can refer to the formula C=R f ×C f ×Ln(E / Vt) / t, where R f is the equivalent impedance of the rear end load of the first capacitor C1, C f is the equivalent capacitive reactance of the rear-end load of the first capacitor C1, E is the energy required for the rear-end load of the first capacitor C1 to work, and Vt is the voltage value across the first capacitor C1, which changes with time t. Afterwards, the capacitance of the first capacitor C1 can be adjusted to a fluctuation range that includes the ideal value by measuring parameters such as line loss and ESR of the actual circuit.

[0032] The constant current drive control module 30 is electrically connected to the bucket-type energy storage module 20 and the laser projection module 40, respectively. In this way, one end of the constant current drive control module 30 can receive the constant boost output signal output by the bucket-type energy storage module 20, and the constant current drive control module 30 can perform constant current processing on the constant boost output signal, so that the constant boost output signal is converted into a constant current output signal, and the other end of the constant current drive control module 30 can output the constant current output signal and provide it to the laser projection module 40 to ensure the normal implementation of the working process of the laser projection module 40 projecting the structured light spot pattern to the target object. Among them, the constant current output signal includes a pulse form and a DC form, that is, the constant current drive control module 30 can convert the constant boost output signal into a constant current output signal in a DC form, and can also convert the constant boost output signal into a constant current output signal in a pulse form. Exemplarily, the amplitude range of the constant current output signal can be 2-20A. Exemplarily, the constant current output signal in pulse form can be 1ms, 30Hz. Exemplarily, the power supply range of the constant current drive control module 30 output to the laser projection module 40 can be 6W-60W. Exemplarily, under the action of the stable high-amplitude constant current output signal in this embodiment, the output peak optical power range of the laser projection module 40 can be 0-18W.

[0033] According to the technical solution in the embodiment of the present invention, the 3D structured light projector adopts a power supply conversion module and a bucket-type energy storage module to process the external voltage, and provides a constant boost output signal to a constant current drive control module. The constant current drive control module performs constant current processing on the constant boost output signal to obtain a stable high-amplitude constant current, supporting the pulse power supply with a pulse width of hundreds of microseconds to milliseconds required by the laser projection module, effectively reducing the power supply demand of the laser projection module for the external voltage. The external voltage can choose to use a universal USB power supply, which can convert the conventional power supply input with a voltage of 5V and a current of less than 1A into a large current constant current power supply output with an adjustable current range of 0-20A, which is then provided to the laser projection module, thereby increasing the output peak light power of the laser projection module, making the scattered spot energy projected on the target object higher, and improving the outdoor depth test performance, so as to adapt to more application scenarios.

[0034] Optionally, Figure 2 is a schematic diagram of the circuit structure of a power supply conversion module and a bucket-type energy storage module provided in an embodiment of the present invention, such as Figure 1 and Figure 2As shown, the power supply conversion module 10 includes a DC-DC converter U1, a first inductor L1, a first diode D1, a first resistor R1 and a second resistor R2; the DC-DC converter U1 includes a first input terminal VIN1, a switch control terminal SW, a first sampling terminal FB and an enable control terminal EN; the first input terminal VIN1 receives an external voltage input signal, and the first input terminal VIN1 is electrically connected to one end of the first inductor L1, the other end of the first inductor L1 is respectively electrically connected to the switch control terminal SW and the positive electrode of the first diode D1, the cathode of the first diode D1 is respectively electrically connected to one end of the first resistor R1 and the input end of the bucket-type energy storage module 20, the other end of the first resistor R1 is respectively electrically connected to the first sampling terminal FB and one end of the second resistor R2, the other end of the second resistor R2 is grounded, and the output end of the bucket-type energy storage module 20 is electrically connected to the enable control terminal EN.

[0035] Specifically, the power supply conversion module 10 includes a DC-DC converter U1, a first inductor L1, a first diode D1, a first resistor R1 and a second resistor R2. The bucket-type energy storage module 20 includes a first capacitor C1. Among them, the first input terminal VIN1 of the DC-DC converter U1 can receive an external voltage input signal, one end of the first inductor L1 is electrically connected to the first input terminal VIN1, and the other end of the first inductor L1 is electrically connected to the switch control terminal SW. The first inductor L1 can realize the functions of electric energy storage and electric energy release, and the switch control terminal SW is also electrically connected to an external controller. The external controller can control the switch control terminal SW to be in an on state or an off state, thereby correspondingly regulating the first inductor L1 to be in an electric energy storage state or an electric energy release state. The positive electrode of the first diode D1 is electrically connected to one end of the first inductor L1, and the negative electrode of the first diode D1 is electrically connected to one end of the first resistor R1 and one end of the first capacitor C1, respectively. In this way, the first diode D1 can act as a rectifier during the process of the power conversion module 10 releasing electric energy, allowing the current to flow in only one direction (from the power conversion module 10 to the bucket-type energy storage module 20). In addition, the first diode D1 can also prevent the current from flowing in the reverse direction to the first inductor L1 during the process of the bucket-type energy storage module 20 releasing electric energy, thereby affecting the charging process of the first inductor L1.

[0036] In addition, one end of the first resistor R1 is electrically connected to the cathode of the first diode D1, the other end of the first resistor R1 is electrically connected to the first sampling terminal FB and one end of the second resistor R2 respectively, and the other end of the second resistor R2 is grounded. In this way, the first resistor R1 and the second resistor R2 constitute a resistor voltage divider, and the first sampling terminal FB can detect the divided voltage of the second resistor R2 and compare it with the preset sampling voltage range set inside the DC-DC converter U1. If the voltage detected by the first sampling terminal FB does not meet the preset sampling voltage range, the DC-DC converter U1 can ensure the output of the required constant boost output signal through internal adjustment.

[0037] Further, the output end of the bucket-type energy storage module 20 is electrically connected to the enable control end EN. In other words, one end of the first capacitor C1 is also electrically connected to the enable control end EN, that is, the constant boost output signal can also be input into the DC-DC converter U1 to control the opening and closing of the DC-DC converter U1. In this way, directly connecting the constant boost output signal to the enable control end EN can delay the circuit soft start time, and there is no need to use an external voltage input signal to directly connect to the enable control end EN, but to allow the external voltage input signal to pass through the first inductor L1, the first diode D1, the first capacitor C1 and other electronic devices before connecting to the enable control end EN. The amplitude rise time of the constant boost output signal is combined with the internal soft start characteristics of the DC-DC converter U1, the circuit soft start time is extended, the startup process is smoother, and the longer soft start time can more effectively reduce the current impact at startup. In addition, it can also reduce the thermal stress and mechanical stress borne by the power supply and load at startup, which helps to improve the reliability and life of the system; the heat generated during startup is more evenly distributed to avoid the generation of local hot spots. Furthermore, by linking the constant boost output signal with the enable control terminal EN, a more advanced power management strategy can be implemented, for example, the DC-DC converter U1 can be started only under certain conditions. Furthermore, the circuit design can be simplified, no external enable signal is required, and the number of required external components can be reduced.

[0038] A specific process analysis example is that when the DC-DC converter U1 is not turned on, the switch control terminal SW is in a disconnected state, and the external voltage input signal is sequentially provided to the constant current drive control module 30 through the first inductor L1, the first diode D1, and the first capacitor C1. At this time, the constant boost output signal at the output end of the bucket-type energy storage module 20 can be understood as changing from a low level state to a high level state, and the high level state is connected to the enable control terminal EN, and the DC-DC converter U1 is turned on. Afterwards, the switch control terminal SW can be controlled by an external controller to switch between the on state and the off state. For example, when the switch control terminal SW is in the on state, the external voltage input signal can be input to the first inductor L1, and will not continue to be input to the first diode D1 behind the first inductor L1. The first inductor L1 can store electric energy, that is, the first inductor L1 is charged under the action of the external voltage input signal. At the same time, the first capacitor C1 can release the stored electric energy to the following constant current drive control module 30 and the laser projection module 40. The constant boost output signal size has a voltage output with a higher amplitude. When the switch control terminal SW is in the off state, the first inductor L1 induces a voltage in the same direction as the external voltage in order to prevent the reduction of the current. The two voltages can be superimposed to effectively increase the amplitude of the constant boost output signal. On the one hand, the external voltage input signal and the first inductor L1 can both charge the first capacitor C1, so that the first capacitor C1 stores electric energy. On the other hand, it can also supply power to the following constant current drive control module 30 and the laser projection module 40. It can be understood that the switch control terminal SW is switched between the on state and the off state, and the first inductor L1 switches between charging and discharging. In this way, the purpose of the constant boost output signal having an amplitude greater than the amplitude of the external voltage input signal is achieved, that is, the boost effect is achieved. In addition, the setting of the first inductor L1 can also smooth the fluctuation of the external voltage input signal, reduce ripples, and provide stable working conditions for the DC-DC converter U1. In addition, the voltage amplitude of the constant boost output signal can be changed by controlling the duty cycle of the switch control terminal SW in the on state (the ratio of the time when the switch control terminal SW is in the on state to the periodic switching time of the switch control terminal SW). For example, the higher the duty cycle of the switch control terminal SW in the on state, the higher the voltage amplitude of the constant boost output signal.

[0039] Also, it should be noted that the combined use of the first inductor L1 and the first capacitor C1 can provide the constant current drive control module 30 with a relatively long period of high-power stable power supply, so as to maintain a period of pulse width lighting time under high power conditions. For example, when the output peak optical power of the laser projection module 40 is ≥4W, the pulse width of the constant current output signal in the form of a pulse can last for 0.1-10ms. Also, it should be noted that the current change of the first inductor L1 has inertia and cannot immediately respond to transient changes in the load. The large-capacity bucket-type first capacitor C1 can be quickly discharged or charged to cope with transient load requirements and reduce transient voltage drops or overshoots. In addition, the first capacitor C1 can also be used as a protection element. For example, in the event of a short circuit or overload, the first capacitor C1 can absorb abnormal currents to protect the entire circuit and adjacent electronic components from damage.

[0040] Optionally, continue to refer to Figure 2 The power supply conversion module 10 further includes a third capacitor C3, one end of the third capacitor C3 is electrically connected to the first input terminal VIN1 of the DC-DC converter U1, and the other end of the third capacitor C3 is grounded. The third capacitor C3 can filter the external voltage input signal to obtain a stabilized voltage output signal, and provide it to the DC-DC converter U1. The third capacitor C3 can smooth the fluctuation of the external voltage input signal and reduce noise and ripple.

[0041] Optionally, continue to refer to Figure 2 The power supply conversion module 10 further includes a seventh resistor R7 and a fourth capacitor C4, one end of the seventh resistor R7 is electrically connected to the output end of the bucket-type energy storage module 20, the other end of the seventh resistor R7 is electrically connected to one end of the fourth capacitor C4 and the enable control end EN, respectively, and the other end of the fourth capacitor C4 is grounded. The seventh resistor R7 and the fourth capacitor C4 can smooth the fluctuation of the constant boost output signal, reduce noise and ripple, and ensure the control stability of the opening and closing of the DC-DC converter U1.

[0042] Optionally, Figure 3 is a circuit structure diagram of a constant current drive control module and a laser projection module provided by an embodiment of the present invention, such as Figure 1 and Figure 3As shown, the constant current drive control module 30 includes a constant current drive chip U2, a sampling unit 31, a first PMOS tube Q1, a first NMOS tube Q2 and a second inductor L2; the constant current drive chip U2 includes a second input terminal VIN2, a second sampling terminal SNS, a first switch regulation terminal DRVH and a second switch regulation terminal DRVL; the second input terminal VIN2 is electrically connected to the output end of the bucket-type energy storage module 20, one end of the sampling unit 31, and the source S of the first PMOS tube Q1, respectively, the second sampling terminal SNS is electrically connected to the other end of the sampling unit 31 and the positive electrode of the laser projection module 40, the negative electrode of the laser projection module 40 is electrically connected to one end of the second inductor L2, the other end of the second inductor L2 is electrically connected to the drain D of the first PMOS tube Q1 and the drain D of the first NMOS tube Q2, the gate G of the first PMOS tube Q1 is electrically connected to the first switch regulation terminal DRVH, the gate G of the first NMOS tube Q2 is electrically connected to the second switch regulation terminal DRVL, and the source S of the first NMOS tube Q2 is grounded.

[0043] Specifically, the constant current drive control module 30 includes a constant current drive chip U2, a sampling unit 31, a first PMOS tube Q1, a first NMOS tube Q2, and a second inductor L2. Among them, the output end of the bucket-type energy storage module 20 is electrically connected to the second input end VIN2 of the constant current drive chip U2 and the source S of the first PMOS tube Q1, respectively, then the constant boost output signal output by the bucket-type energy storage module 20 can be transmitted to the constant current drive chip U2 and the first PMOS tube Q1, that is, the constant current drive chip U2 and the first PMOS tube Q1 can both receive the constant boost output signal, and the constant current drive chip U2 and the first PMOS tube Q1 cooperate with each other to play a role in voltage division and stabilizing the output current. Exemplarily, the second input end VIN2 can be electrically connected to one end of the first capacitor C1 in the bucket-type energy storage module 20, so as to achieve Figure 2 The circuit diagram shown is Figure 3The electrical connection relationship of the circuit diagram shown in FIG. 4 is shown in FIG. 4 . For example, the second input terminal VIN2 can be understood as a power supply pin, which provides the constant current drive chip U2 with the power required for operation and ensures the stability of the power supply. In addition, the second input terminal VIN2 is also electrically connected to one end of the sampling unit 31, the second sampling terminal SNS is electrically connected to the other end of the sampling unit 31, and the second sampling terminal SNS is also electrically connected to the positive electrode of the laser projection module 40. Then, the constant current driving chip U2 can detect the voltage drop at both ends of the sampling unit 31 through the second sampling terminal SNS, and calculate the current flowing through the sampling unit 31. In addition, the constant current driving chip U2 can also compare the detected voltage drop with the reference voltage to internally adjust the switching frequency of the first switch control terminal DRVH and the second switch control terminal DRVL. Since the gate G of the first PMOS tube Q1 is electrically connected to the first switch control terminal DRVH, and the gate G of the first NMOS tube Q2 is electrically connected to the second switch control terminal DRVL, the on-off frequency of the first PMOS tube Q1 and the first NMOS tube Q2 is correspondingly adjusted to adjust the output current, that is, a constant current output signal, to ensure that the constant current is output to the laser projection module 40. Exemplarily, the sampling unit 31 may be the eighth resistor R8, and the high-side current detection technology is used to accurately control the amplitude of the constant current output signal by detecting the voltage drop on the eighth resistor R8 connected in series between the bucket-type energy storage module 20 and the second sampling terminal SNS, thereby reducing the influence of ground wire noise or ground wire rebound on the current detection accuracy. In addition, the high-side current detection technology is used to reduce the use of the ground wire loop, thereby reducing the influence of the ground wire loop on the overall electromagnetic compatibility, reducing electromagnetic interference, and improving the utilization rate of the circuit routing.

[0044] It should also be noted that the first PMOS tube Q1 and the first NMOS tube Q2 are turned on or off simultaneously, that is, the first switch control terminal DRVH and the second switch control terminal DRVL work alternately to facilitate voltage conversion. When the first switch control terminal DRVH controls the first PMOS tube Q1 to be turned off, the second switch control terminal DRVL controls the first NMOS tube Q2 to be turned on synchronously, and the constant current output signal input from the positive electrode of the laser projection module 40 is transmitted to one end of the second inductor L2 through the negative electrode of the laser projection module 40. The second inductor L2 can store electrical energy, that is, the constant current output signal charges the second inductor L2. Furthermore, when the first switch regulation terminal DRVH controls the first PMOS tube Q1 to be turned on, the second switch regulation terminal DRVL controls the first NMOS tube Q2 to be turned off synchronously, and the second inductor L2 can also be electrically connected to the bucket-type energy storage module 20 through the first PMOS tube Q1. That is, in a specific embodiment, the second inductor L2 is electrically connected to the first capacitor C1 through the first PMOS tube Q1. At this time, when the second inductor L2 is discharged, the first capacitor C1 can be charged, which further saves electric energy and improves the overall electric energy utilization rate of the 3D structured light projector in this embodiment.

[0045] In addition, it can be understood that the circuit structure of the first PMOS tube Q1, the first NMOS tube Q2 and the second inductor L2 in the present embodiment is designed using synchronous rectification technology and freewheeling technology, and ultra-low on-resistance MOS tubes (first PMOS tube Q1, first NMOS tube Q2) are used to replace high on-resistance diodes. The greater the impedance, the higher the forward voltage drop, thereby reducing switching losses and improving the conversion efficiency of the entire circuit. In addition, the switching operations of the first PMOS tube Q1 and the first NMOS tube Q2 are more coordinated, and they switch states (on or off) almost at the same time, reducing the rate of change of current and voltage, that is, reducing the sudden change of current and voltage, thereby reducing electromagnetic interference (EMI) and noise generated during high-speed switching.

[0046] To sum up, the direction of electric energy flow in the constant current drive control module 30 is that the constant boost output signal output from the output end of the bucket-type energy storage module 20 is input to the constant current drive chip 21, the sampling unit 31, the first PMOS tube Q1, the first NMOS tube Q2 and the second inductor L2 of the constant current drive control module 30, wherein the acquisition of the voltage drop across the sampling unit 31 can be beneficial to timely regulation of the output current, and correspondingly adjust the switching frequency of the first switch regulation end DRVH and the second switch regulation end DRVL to transmit the required constant current output signal with a stable amplitude to the positive electrode of the laser projection module 40.

[0047] Optionally, continue to refer to Figure 3The constant current drive control module 30 also includes a digital-to-analog conversion modulation unit 32; the constant current drive chip U2 also includes an analog dimming input terminal ADIM; the digital-to-analog conversion modulation unit 32 is electrically connected to the analog dimming input terminal ADIM, and the digital-to-analog conversion modulation unit 32 is used to convert an external PWM input signal into a preset analog voltage output signal to adjust the amplitude of the constant current output signal.

[0048] Specifically, the constant current output signal includes a direct current form and a pulse signal. In this embodiment, a digital-to-analog conversion modulation unit 32 is additionally provided, and the digital-to-analog conversion modulation unit 32 is electrically connected to the analog dimming input terminal ADIM of the constant current driver chip U2. The digital-to-analog conversion modulation unit 32 can convert the external PWM input signal into a preset analog voltage output signal, and transmit it to the constant current driver chip U2. The constant current driver chip U2 can perform internal adjustments according to the received analog voltage output signal to change the amplitude of the output constant current output signal, and the corresponding output pulse form of the constant current output signal. Exemplarily, the digital-to-analog conversion modulation unit 32 can convert the digital signal of the external PWM input signal into an analog signal, that is, the digital-to-analog conversion modulation unit 32 can realize the level conversion function, converting the voltage of the input digital signal (exemplarily, 3.3V) into the voltage range of the analog signal required by the analog dimming input terminal ADIM (exemplarily, 0.5-3V), and output it to the analog dimming input terminal ADIM. It can be understood that after the digital-to-analog conversion modulation unit 32 converts the digital signal into an analog signal, it is provided to the constant current driver chip U2. The analog signal is used to control the output of the constant current output signal corresponding to the constant current driver chip U2, and a smooth current output can be obtained. If the digital signal is directly used to control the output of the constant current output signal corresponding to the constant current driver chip U2, the current waveform obtained is a pulse output. The analog dimming method (analog signal input to the analog dimming input terminal ADIM) can modulate a smoother current waveform compared to the pulse dimming method (digital signal input to the analog dimming input terminal ADIM), which is conducive to the generation of a stable constant current output signal, and the analog dimming input terminal ADIM receives an analog signal and can change continuously, thereby realizing fine adjustment of the projection brightness of the laser projection module 40. That is, the external PWM input signal is conducive to the precise control of the analog dimming input terminal ADIM, and the final signal reaching the analog dimming input terminal ADIM is a relatively stable analog voltage signal. In addition, it should be noted that the digital signal can be a PWM signal, which can perform multi-functional adjustments. It can control the constant current output signal corresponding to the constant current driver chip U2 (by controlling the duty cycle of the PWM signal, and correspondingly changing the size of the analog signal received by the analog dimming input terminal ADIM of the constant current driver chip U2, thereby changing the current size output to the laser projection module 40), and can control the pulse width of the pulse form of the constant current output signal output by the constant current driver chip U2 by controlling the presence or absence of the PWM signal, thereby obtaining a high constant current pulse output.

[0049] Further, continue to refer to Figure 3The digital-to-analog conversion modulation unit 32 includes a second NMOS transistor Q3, a third NMOS transistor Q4, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a plurality of sixth resistors R6 and a plurality of second capacitors C2; the digital-to-analog conversion modulation unit 32 also includes a PWM control signal input terminal and an external voltage signal input terminal; the gate G of the second NMOS transistor Q3 is electrically connected to the PWM control signal input terminal, the drain D of the second NMOS transistor Q3 is electrically connected to one end of the third resistor R3 and one end of the fourth resistor R4, and the source S of the second NMOS transistor Q3 is electrically connected to the PWM control signal input terminal. The gate G of the third NMOS tube Q4 is electrically connected to the other end of the third resistor R3, the drain D of the third NMOS tube Q4 is electrically connected to one end of the fifth resistor R5, the source S of the third NMOS tube Q4 is grounded, the other end of the fifth resistor R5 is electrically connected to the other end of the fourth resistor R4 and the external voltage signal input end respectively, and each sixth resistor R6 is sequentially connected in series between the drain D of the third NMOS tube Q4 and the analog dimming input end ADIM, one end of the second capacitor C2 is electrically connected to one end of the sixth resistor R6, and the other end of the second capacitor C2 is grounded.

[0050] Specifically, the digital-to-analog conversion modulation unit 32 includes a PWM control signal input terminal and an external voltage signal input terminal, wherein the external PWM input signal inputted by the PWM control signal input terminal is high and low level alternately changed, and the high and low levels in the external PWM input signal described in this embodiment are relative, and only represent the amplitude comparison of two level signals in the external PWM input signal, and are not limited. A specific process analysis example is that when the external PWM input signal inputted by the PWM control signal input terminal is high level, the gate voltage of the second NMOS tube Q3 is greater than the source voltage of the second NMOS tube Q3, and the gate voltage of the third NMOS tube Q4 is less than the source voltage of the third NMOS tube Q4, then the second NMOS tube Q3 is turned on, and the third NMOS tube Q4 is turned off, and the external voltage inputted by the external voltage signal input terminal can charge the RC circuit composed of the sixth resistor R6 and the second capacitor C2, and the RC circuit can also filter out the high frequency signal in the digital-to-analog conversion modulation unit 32, reduce the ripple, improve the linearity of the signal, and provide a preset analog voltage output signal for the analog dimming input terminal ADIM, so as to adjust the amplitude of the constant current output signal accordingly. When the external PWM input signal input to the PWM control signal input terminal is at a low level, the gate voltage of the second NMOS tube Q3 is less than the source voltage of the second NMOS tube Q3, and the gate voltage of the third NMOS tube Q4 is greater than the source voltage of the third NMOS tube Q4, then the second NMOS tube Q3 is turned off, the third NMOS tube Q4 is turned on, and the RC circuit composed of the sixth resistor R6 and the second capacitor C2 can be discharged, and continue to provide a preset analog voltage output signal for the analog dimming input terminal ADIM. In this way, the constant current drive chip U2 can process the received constant boost output signal according to the preset analog voltage output signal to change the output amplitude of the constant current output signal and provide it to the laser projection module 40. For example, the voltage output to the analog dimming input terminal ADIM can be controlled by controlling the duty cycle of the high level in the external PWM input signal input to the PWM control signal input terminal (the ratio of the high level in the external PWM input signal input to the time of the cycle). The higher the duty cycle, the higher the voltage output to the analog dimming input terminal ADIM, thereby controlling the amplitude of the constant current output signal output to the laser projection module 40.It should also be noted that, in this embodiment, the second NMOS tube Q3 and the third NMOS tube Q4 are both N-type MOS tubes, and the digital-to-analog conversion modulation unit 32 adopts the coordination of the second NMOS tube Q3 and the third NMOS tube Q4 being turned on or off to convert the external PWM input signal input by the PWM control signal input terminal into an analog signal output, and the MOS tube has a small impedance and a small switching loss. In addition, a low-voltage MOS tube can be selected, and the driving circuit matched with the low-voltage driving characteristics can be simpler, reducing external components and costs. In fact, a P-type MOS tube can also be used to achieve the same level conversion effect, which will not be repeated in this embodiment.

[0051] In addition, the digital-to-analog conversion modulation unit 32 includes a plurality of sixth resistors R6 and a plurality of second capacitors C2, and each of the sixth resistors R6 is sequentially connected in series between the drain D of the third NMOS tube Q4 and the analog dimming input terminal ADIM, one end of the second capacitor C2 is electrically connected to one end of the sixth resistor R6, and the other end of the second capacitor C2 is grounded. It can be understood that the plurality of sixth resistors R6 and the plurality of second capacitors C2 can form a multi-stage RC circuit in series (which can be understood as an integral low-pass filter circuit, which is the lowest cost DA digital-to-analog conversion circuit at present, effectively reducing the circuit cost), and any of the sixth resistors R6 and the second capacitor C2 adjacent thereto is a first-stage RC circuit therein. Exemplarily, the present embodiment here only takes three sixth resistors R6 and three second capacitors C2 as examples for drawing and explanation, and the three-stage RC circuit formed can be beneficial for converting the external PWM input signal inputted by the PWM control signal input terminal into a corresponding analog voltage output signal.

[0052] Furthermore, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 play the role of voltage division and current limiting, which can ensure the normal conduction or cutoff of the second NMOS transistor Q3 and the third NMOS transistor Q4. Figure 3 , the digital-to-analog conversion modulation unit 32 also includes a ninth resistor R9 and a tenth resistor R10, one end of the ninth resistor R9 is electrically connected to the PWM control signal input terminal, the other end of the ninth resistor R9 is electrically connected to the gate G of the second NMOS tube Q3 and one end of the tenth resistor R10, respectively, and the other end of the tenth resistor R10 is electrically connected to the source S of the second NMOS tube Q3. The setting of the ninth resistor R9 and the tenth resistor R10 can also play a role in voltage division and current limiting, ensuring the normal conduction or cutoff of the second NMOS tube Q3. Of course, the digital-to-analog conversion modulation unit 32 can also include other resistance elements to ensure the normal conduction or cutoff of the second NMOS tube Q3 and the third NMOS tube Q4, and this embodiment will not be described one by one.

[0053] Optionally, continue to refer to Figure 3The constant current drive control module 30 also includes a fifth capacitor C5, one end of which is electrically connected to the output end of the bucket-type energy storage module 20 and the second input end VIN2 of the constant current drive chip U2, and the other end of the fifth capacitor C5 is grounded. The fifth capacitor C5 can filter the received constant boost output signal, smooth the boost voltage, and reduce the noise and ripple of the boost voltage.

[0054] Optionally, continue to refer to Figure 3 The constant current drive control module 30 further includes a sixth capacitor C6, one end of which is electrically connected to the second sampling terminal SNS of the constant current drive chip U2 and the positive electrode of the laser projection module 40, and the other end of which is electrically connected to the negative electrode of the laser projection module 40 and one end of the second inductor L2. The sixth capacitor C6 can filter the received constant current output signal, smooth the constant current, and reduce the noise and ripple of the constant current.

[0055] In summary, this embodiment can process the external voltage input signal through the circuit design of the power supply conversion module 10, the bucket-type energy storage module 20 and the constant current drive control module 30, so as to avoid the problem that the voltage, current, power and other parameters of the external voltage input signal are too small, and the external voltage input signal is directly output to the laser projection module 40, resulting in the laser projection module 40 The projection light power is too small, which in turn leads to the depth value measurement and calculation of the laser projection module 40 is limited. It can be understood that in order to further improve the output peak light power of the laser projection module 40, the internal component structure of the laser projection module 40 can also be designed to avoid the inherent performance limitation of the planar array laser 41 inside the laser projection module 40 (the oxidation aperture of the light-emitting hole is generally <11μm), resulting in a sudden drop in the photoelectric conversion efficiency as the input current increases, and even if the input current is increased, the output peak light power of the planar array laser 41 cannot be increased. The specific analysis is as follows.

[0056] Optionally, Figure 4 is a schematic diagram of the structure of a laser projection module provided by an embodiment of the present invention. Figure 1 and Figure 4 As shown, the laser projection module 40 includes a planar array laser 41 and an optical element module; the planar array laser 41 is used to emit a laser beam; the optical element module is located on the propagation path of the laser beam, and the optical element module is used to collimate and diffract the laser beam to project a structured light spot pattern.

[0057] Exemplarily, the area array laser 41 can select a high-power area array laser 41, whose output peak optical power range is ≥4W, so that the speckle energy projected on the target object is higher, effectively improving the outdoor depth test performance.

[0058] Optionally, the optical element module includes an optical collimation unit 42 and an optical diffraction unit 43, which are sequentially located on the propagation path of the laser beam emitted by the planar array laser 41, wherein the optical collimation unit 42 can collimate the laser beam to obtain a collimated laser beam, and the optical diffraction unit 43 can diffract the collimated laser beam to obtain a diffracted laser beam, that is, to replicate the diffused structural spot pattern with a larger field of view angle.

[0059] Optionally, Figure 5 is a schematic diagram of a cross-sectional structure of a planar array laser provided by an embodiment of the present invention, such as Figure 5 As shown, the surface array laser 41 includes a plurality of light-emitting holes, that is, the surface array laser 41 can be composed of a series of light-emitting hole arrays, which are pseudo-randomly distributed. Exemplarily, the surface array laser 41 can be a VCSEL (vertical cavity surface emitter), and the output light wavelength of the surface array laser 41 can be infrared light. Figure 5 The planar array laser 41 shown includes an N-type electrode 411, a substrate layer 412, an N-type DBR (distributed Bragg reflector) 413, an active layer 414, an oxide layer 415, a P-type DBR (distributed Bragg reflector) 416, and a P-type electrode 417. When a constant current output signal is provided to the planar array laser 41, when the current is provided to the N-type electrode 411 and the P-type electrode 417 for injection, electrons are injected from the N-type electrode 411, and holes are injected from the P-type electrode 417. The injected electrons and holes are recombined in the active layer 414 to generate photons, and the generated photons are reflected back and forth between the N-type DBR 413 and the P-type DBR 416, and are further amplified when passing through the active layer 414 to form a laser beam. Since the reflectivity of the P-type DBR 416 is relatively low, some photons escape from its upper surface to form the output of the laser beam. Furthermore, the oxide layer 415 is usually made of AlGaAs (aluminum gallium arsenide) material. The function of the oxide layer 415 is to limit the area of ​​the current injection region and only allow the current to be injected into the active layer 414 through a specific aperture. The current injection region can be understood as Figure 5 The area corresponding to the oxidation aperture OA shown. In addition, it can be understood that Figure 5 The active layer 414 shown has only one layer. In some embodiments, the active layer 414 can be multiple layers. Compared with the single-layer active layer 414, the multiple-layer active layer 414 can further improve the energy amplification factor of the laser beam passing through the active layer 414, improve the PCE (photoelectric conversion efficiency) output by the array laser 41, and achieve a higher output peak optical power at a smaller current.

[0060] It should be noted that, in order to project a light spot with a certain spot density, the existing planar array laser 41 needs to integrate more light-emitting holes in a smaller light-emitting area, such as 0.25 mm 2More than 200 light-emitting holes are integrated in the light-emitting area. The spacing between these light-emitting holes is small. Generally, the minimum spacing pitch between the light-emitting holes is ≤28um, and the oxidation aperture OA of the light-emitting holes is also affected by the minimum spacing pitch between the light-emitting holes. Generally, the oxidation aperture OA is <11um. At this time, the optimal working current of the array laser 41 is <2A, and the divergence angle of the array laser 41 is <22°. When the power supply current continues to increase, the energy density per unit area of ​​the active layer 414 surges, and the heat accumulation of the light-emitting holes will lead to: 1) PCE (power conversion efficiency, that is, the value of the output optical power divided by the input electrical power) drops sharply and fails to reach the required target output power; 2) The temperature of the active layer 414 is too high, which seriously affects the life and reliability of the device; 3) The increase in the temperature of the active layer 414 will cause the refractive index of the material to change, thereby affecting the laser mode and beam quality, resulting in an increase in the beam divergence angle. In addition, the value of the minimum pitch between the light-emitting holes and the value of the oxidation aperture OA of the light-emitting holes need to be set within a certain range. The existing planar array laser 41 also has the situation that the value of the minimum pitch between the light-emitting holes and the value of the oxidation aperture OA of the light-emitting holes are set unreasonably, which will lead to: 1) the divergence angle of the planar array laser 41 becomes larger. The larger the divergence angle, the larger the projected scattered spot area. Under the same energy, the larger the scattered spot area, the lower the energy density, which is not conducive to depth calculation; 2) the uniformity of the light output energy of a single light-emitting hole of the planar array laser 41 becomes worse, and the energy attenuation of the central beam is serious, which is not conducive to depth calculation; 3) the scattered spot density of the planar array laser 41 is reduced, and the number of light-emitting holes integrated on the same light-emitting area is small, which will affect the depth measurement accuracy; 4) the area size corresponding to the effective light-emitting area of ​​the planar array laser 41 becomes larger, which greatly increases the cost and is not conducive to the design of subsequent optical element modules. That is, the existing planar array laser 41 cannot meet the use requirements for outdoor applications.

[0061] Therefore, based on the above technical problems, the present embodiment optionally includes a plurality of light-emitting holes, the minimum spacing between the light-emitting holes is pitch; and 35 μm ≤ pitch ≤ 50 μm, and / or, the oxidation aperture of each light-emitting hole is OA, and 15 μm ≤ OA ≤ 30 μm; and / or, the effective light-emitting area of ​​the surface array laser 41 is S, and 0.35 mm 2 ≤S≤1mm 2, the effective light-emitting area S of the surface array laser 41 can be understood as the product of the center distance between the upper and lower edge light-emitting holes and the center distance between the left and right edge light-emitting holes of the surface array laser 41. In this way, more than 200 light-emitting holes are integrated in the effective light-emitting area, and the divergence angle of the surface array laser 41 (the divergence angle is defined here as the angle of the light beam where the energy drops to the highest energy 1 / e2) is finally in the range of ≤30°, and the output peak optical power range of the surface array laser 41 is ≥4W. In other words, this embodiment provides a reasonable design of the effective light-emitting area S of the surface array laser 41, the minimum pitch between the light-emitting holes, and the oxidation aperture OA of the light-emitting holes, so that the surface array laser 41 outputs a laser beam with a target optical power and divergence angle. For example, the oxidation aperture OA of the light-emitting holes can be increased by increasing the minimum pitch between the light-emitting holes. Thus, by setting the minimum pitch between the light-emitting holes to be ≥15 μm, the oxidation aperture OA of the light-emitting holes can be increased to at least 15 μm, which greatly increases the area of ​​current injection of the active layer 414 and reduces the energy density per unit area. The overall output power of the planar array laser 41 can be increased by increasing the injection current. Thus, by improving the oxidation aperture OA of the light-emitting holes, the output light power is increased and the divergence angle is compressed, so that the projected scattered spot energy meets the outdoor depth test requirements; by improving the minimum pitch between the light-emitting holes, the overall heat dissipation performance and reliability are improved; as many light-emitting holes as possible are set on a smaller effective light-emitting area, while taking into account the effective light-emitting area and the distribution density of the light-emitting holes. On the one hand, a larger speckle density is conducive to the accuracy of depth calculation, and on the other hand, a smaller effective light-emitting area can reduce the overall material cost; even when used under strong outdoor light, the scattered spot energy projected on the object by the planar array laser 41 can be higher than the ambient light, and the depth calculation of the structured light is more accurate.

[0062] Figure 6 FIG. 1 is a schematic diagram of a spot distribution of a planar array laser in combination with an optical element module provided by an embodiment of the present invention. Figure 6 As shown, the planar array laser 41 can be understood as the existing planar array laser 41, the first minimum pitch pitch1 between the light-emitting holes is ≤28μm, the first oxidation aperture OA1 of the light-emitting holes is ≤11μm, and the divergence angle is ≤22°. After passing through the existing optical element module, it is replicated into a speckle pattern with a larger field of view. Figure 6 The optical collimation unit 42 (F number (the inverse of the relative aperture) ≥ 2.4, the diameter of the maximum imaging circle (the circular imaging range that the lens can clearly image) ≤ 0.9 mm) and the optical diffraction unit 43 (the replication order is M×N, and M=N=2) in the optical element module are used as examples for drawing and explanation.

[0063] Figure 7 FIG. 1 is a schematic diagram of a spot distribution of another planar array laser in combination with an optical element module provided by an embodiment of the present invention. Figure 7 As shown, the planar array laser 41 can be understood as the planar array laser 41 of this embodiment, the second minimum pitch between the light-emitting holes is pitch2, and 35μm≤pitch2≤50μm, the second oxidation aperture OA2 of the light-emitting hole is 15μm≤OA2≤30μm, and the divergence angle is ≤30°. The light spot diagram projected after passing through the existing optical element module can clearly show that: 1) The F number of the optical collimation unit 42 in the existing optical element module is relatively large. When the divergence angle of the planar array laser 41 is ≥2×arcsin(1 / 2F), the light emitted by the planar array laser 41 cannot be fully collimated by the optical collimation unit 42 to be projected as a light spot, and part of the light beam will be emitted from the optical collimation unit 42 as stray light, such as Figure 7 As shown in M, stray light will serve as background light and noise in the speckle pattern, affecting the signal-to-noise ratio of the speckle pattern and ultimately affecting the accuracy of depth calculation; 2) The imaging circle size of the optical collimation unit 42 in the existing optical element module is small. When the edge light-emitting hole of the array laser 41 exceeds the imaging circle position, part of the light beam emitted by the edge light-emitting hole of the array laser 41 cannot be collimated by the optical collimation unit 42, and will also be emitted from the optical collimation unit 42 as stray light, further reducing the signal-to-noise ratio of the speckle pattern. In addition, the energy emitted from the edge point is significantly lower than that from the center point, such as Figure 7 The energy of the projected edge scattered spot B1 is obviously lower than that of the central scattered spot A1, which affects the uniformity of the speckle and ultimately reduces the depth calculation accuracy; 3) The optical collimation unit 42 in the existing optical element module is matched with the surface array laser 41 in this embodiment, and the aberration is large, so that the scattered spot area after collimation by the optical collimation unit 42 is significantly increased. Although the energy of the entire scattered spot is increased, the scattered spot energy density is reduced (scattered spot energy density = scattered spot energy / scattered spot area), which also affects the depth calculation accuracy; 4) The focal length of the optical collimation unit 42 in the existing optical element module is small. After the large-sized surface array laser 41 passes through the optical collimation unit 42, the output field angle is large, the speckle pattern area is large, and the projected speckle density is reduced (compared with Figure 6 and Figure 7 , in the projected speckle pattern, Figure 7 The number of scattered spots per unit area is less than Figure 6 The number of scattered spots per unit area in the image affects the depth calculation.

[0064] Therefore, based on the above technical problems, this embodiment provides an optical collimation unit 42, so that the reciprocal of the relative aperture of the optical collimation unit 42 is F number, and F number ≤ 1.9; and / or, the maximum imaging circle diameter of the optical collimation unit 42 is R, and R ≥ 1mm; and / or, the focal length of the optical collimation unit 42 is L, and L ≥ 4mm; and / or, the relative illumination of the optical collimation unit 42 is RI, and RI ≥ 94%. The optical collimation unit 42 is matched with the surface array laser 41 provided in this embodiment, so that the surface array laser 41 can obtain a small size and a better uniformity of scattered spots after being collimated by the optical collimation unit 42, which greatly improves the energy density and brightness of the scattered spots projected by the surface array laser 41. The laser light emitted by the surface array laser 41 is collimated by the optical collimation unit 42 as much as possible, and can be compatible with a larger area of ​​the surface array laser 41.

[0065] Optionally, Figure 8 is a schematic structural diagram of an optical collimation unit provided by an embodiment of the present invention, such as Figure 8 As shown, the optical collimation unit 42 includes a first lens 421, a second lens 422 and a third lens 423 with a common optical axis, and the first lens 421, the second lens 422 and the third lens 423 are sequentially located on the propagation path of the laser beam emitted by the area array laser 41. Among them, the area array laser 41 is the object side, and the target object is the image side. Exemplarily, in order to reduce the overall cost of the optical collimation unit 42, the first lens 421, the second lens 422 and the third lens 423 are all made of plastic. Exemplarily, the first lens 421 has a positive optical focal length, and its object side surface is a convex surface and the image side surface is a concave surface. The second lens 422 has a positive optical focal length, and its object side surface is a concave surface and the image side surface is a convex surface. The third lens 423 has a positive optical focal length, and its object side surface is a concave surface and the image side surface is a convex surface. Exemplarily, the first lens 421, the second lens 422 and the third lens 423 are all even-order aspherical lenses, which can effectively correct various aberrations, reduce the design difficulty of the optical collimation unit 42 and the number of lenses used, and the surface shape of the even-order aspherical lens is smoother and easier to manufacture.

[0066] Optionally, continue to refer to Figure 8 , the refractive index of at least two of the first lens 421, the second lens 422 and the third lens 423 is greater than 1.6. Exemplarily, the refractive index of the second lens 422 and the third lens 423 are both greater than 1.6. In this way, by reasonably matching the refractive index of each lens material, it is beneficial to correct the aberration of the optical collimation unit 42 and improve the imaging quality of the optical collimation unit 42. The use of a high refractive index lens can reduce the design difficulty of the optical collimation unit 42 and compress the volume of the optical collimation unit 42.

[0067] Optionally, continue to refer to Figure 8, the first lens 421 needs to satisfy the condition 0.5<r1<r2<2, where r1 represents the radius of curvature of the object side of the first lens 421, and r2 represents the radius of curvature of the image side of the first lens 421. In this way, by setting a smaller radius of curvature, the light collecting ability of the first lens 421 can be improved, allowing a light beam with a larger angle and object height to be emitted through the first lens 421. In addition, by constraining the surface relationship between the object side and the image side of the first lens 421, it is beneficial to the processing and manufacturing of the lens, and at the same time, the tolerance sensitivity can be reduced.

[0068] Optionally, continue to refer to Figure 8 , the second lens 422 needs to satisfy the condition -2<r3<r4<-0.5, where r3 represents the radius of curvature of the object side of the second lens 422, and r4 represents the radius of curvature of the image side of the second lens 422. In this way, by setting a smaller radius of curvature, the light collecting ability of the second lens 422 can be improved, allowing more light emitted from the first lens 421 to pass through the second lens 422. In addition, by constraining the surface relationship between the object side and the image side of the second lens 422, it is beneficial to the processing and manufacturing of the lens, and at the same time, the tolerance sensitivity can be reduced. In addition, the object side of the second lens 422 is set as a concave surface, which can effectively reconcile the field curvature, distortion and other aberrations generated by the first lens 421, and reduce the size of the projected light spot.

[0069] Optionally, continue to refer to Figure 8 , the third lens 423 needs to satisfy the conditions r5<r6<0, and 0.6<r6 / r5<1, where r5 represents the curvature radius of the object side of the third lens 423, and r6 represents the curvature radius of the image side of the third lens 423. In this way, by constraining the surface relationship between the object side and the image side of the third lens 423, it is beneficial to the processing and manufacturing of the lens, and at the same time, the tolerance sensitivity can be reduced, allowing more light emitted from the second lens 422 to pass through the third lens 423, and the object side of the third lens 423 is set to be a concave surface, which further compresses the field curvature, distortion and other aberrations generated by the first lens 421 and the second lens 422, and further reduces the size of the projected light spot.

[0070] Optionally, continue to refer to Figure 8 , the first lens 421, the second lens 422 and the third lens 423 need to satisfy the condition 1<d23 / d12<2, and f1<f3, where d12 represents the distance between the first lens 421 and the second lens 422, d23 represents the distance between the second lens 422 and the third lens 423, f1 represents the focal length of the first lens 421, and f3 represents the focal length of the third lens 423. This condition limits the ratio of the first lens 421 and the third lens 423, expands the aperture of the beam incident to the third lens 423, averages the proportion of different object heights passing through the optical collimating element 32, and improves the brightness uniformity of the scattered spot projection.

[0071] In addition, optionally, continue to refer to Figure 8 The optical collimating element 32 also includes an aperture, which is located on the propagation path of the light beam emitted by the third lens 423.

[0072] According to the conditions satisfied by the first lens 421 , the second lens 422 and the third lens 423 , this embodiment provides a preferred embodiment. Figure 8 The half height of the area array laser 41 (which can also be understood as a light-emitting object surface) shown is 0.7 mm (full height is 1.4 mm), and the divergence angle of the light source point (object point) of the area array laser 41 is 34°. Figure 8 The light propagation path shown is a schematic diagram of a laser beam with a divergence angle of 34° emitted by a light source point with an object height of 0.7 mm passing through the first lens 421, the second lens 422 and the third lens 423 in sequence. It can be clearly seen that the optical collimating element 32 can fully collimate the large-size and large-divergence laser beam. And, Table 1 is Figure 8 A schematic diagram of relevant parameters of each lens in the optical collimation element is shown. Fig. 9 yes Figure 8 Schematic diagram of distortion parameters of the optical collimation element shown, Fig. 9 As shown, it can be seen that the distortion is <0.34%. Fig.10 yes Figure 8 The schematic diagram of the scattered spot size of the optical collimator at different image heights at 1m is shown. Fig.10 As shown, it can be seen that the spot size is less than 0.34 mm. Fig.11 yes Figure 8 The relative illumination diagram of the optical collimation element is shown in FIG. Fig.11 As shown in Table 2, the relative illumination of the whole image is > 97.9%. Figure 8 The optical characteristic simulation schematic diagram of the optical collimating element is shown. In this way, the present embodiment provides a reasonable setting of the relevant parameters of the first lens 421, the second lens 422 and the third lens 423, constrains the curvature radius and the optical focal length of each lens, and the spacing relationship between each lens, ensures that the optical collimating unit 42 has a strong light receiving ability, makes the optical collimating unit 42 have a higher relative illumination, reduces the size of the projected scattered spot, and improves the uniformity of the projected speckle. The collimation degree of the optical collimating unit 42 is very small, and can collimate the light source point with a large divergence angle and a large spot size into a smaller scattered spot for emission.

[0073] Table 1

[0074] Surface type Curvature radius (mm) Thickness(mm) Material refractive index First lens object side even aspherical surface 1.08 1.21 1.54 The first lens image side even aspherical surface 1.36 0.9 1.54 Second lens object side even aspherical surface -1.6 0.71 1.64 Second lens image side even aspherical surface -1.2 1.18 1.64 The third lens side even aspherical surface -1.77 0.82 1.64 The third lens image side even aspherical surface -1.59 0.18 1.64

[0075] Table 2

[0076] Simulation value Overall effective focal length f 4.5mm The focal length of the first lens is f1 4mm The focal length of the third lens is f3 9.35mm d23 / d12 1.31 Relative Illuminance RI ＞97.9％ F-number 1.71 Divergence angle 34° Maximum imaging circle diameter R 1.4mm Field of view FOV 17.7°

[0077] Fig.12FIG. 1 is a schematic diagram of a spot distribution of another planar array laser in combination with an optical element module provided by an embodiment of the present invention. Fig.12 As shown, the area array laser 41 can be understood as the area array laser 41 of this embodiment, the second minimum pitch between the light-emitting holes is pitch2, and 35μm≤pitch2≤50μm, and the second oxidation aperture OA2 of the light-emitting holes is 15μm≤OA2≤30μm. After passing through the optical element module (optical collimation unit 42 and optical diffraction unit 43) of this embodiment, the light spot pattern projected can obviously be seen to obtain a speckle pattern with a larger field of view, and the signal-to-noise ratio of the speckle pattern is not affected, and the depth calculation accuracy is not affected.

[0078] Optionally, continue to refer to Figure 4 The optical collimating unit 42 and the optical diffraction unit 43 can also be replaced by a super lens, which has the collimating function of the optical collimating unit 42 and the replicating and diffusing function of the optical diffraction unit 43. This embodiment is only an example and will not be described in detail.

[0079] In another specific embodiment, the 3D structured light projector includes a power conversion module 10, a bucket-type energy storage module 20, a constant current drive control module 30 and at least one laser projection module 40, and each laser projection module 40 is electrically connected to the constant current drive control module 30 respectively. Fig.13 is a schematic diagram of the structure of another 3D structured light projector provided by an embodiment of the present invention. Fig.13 As shown, the number of laser projection modules 40 in the 3D structured light projector can be two, and the two laser projection modules 40 are electrically connected to the constant current drive control module 30 respectively, and the projection spot areas of the two laser projection modules 40 are spliced ​​into a larger spot area. It can be understood that the two laser projection modules 40 used in this embodiment can further improve the projection area of ​​the spot structure diagram and enhance the energy of the projected scattered spots, so that the overall 3D structured light projector can measure more depth information at a farther distance, and improve the measurement accuracy of the entire projection surface, further improve the energy density of each scattered spot in the speckle diagram, and solve the problem of inaccurate or missing depth measurement due to the low energy of the projected edge scattered spots. In addition, illustratively, the number of laser projection modules 40 in the 3D structured light projector can also be more than two, and this embodiment is only an example and is not limited here.

[0080] Fig.14 yes Fig.13 A schematic diagram of the spatial distribution of the light spot area projected by the 3D structured light projector is shown in FIG. Fig.13 and Fig.14As shown, one of the laser projection modules 40 can project a speckle pattern corresponding to area 41, and the other laser projection module 40 can project a speckle pattern corresponding to area 42. Areas 41 and 42 are adjacently arranged, and there may be a partially overlapping area. For example, the two laser projection modules 40 can be driven to illuminate at intervals, and the two corresponding infrared images can be fused to obtain a speckle pattern for calculating the depth, and then the depth calculation can be performed. Since there are two laser projection modules 40, the number of speckles that need to be set for each laser projection module 40 is only half of the original number. In this way, under the same driving current, the energy of a single speckle projected by a single laser projection module 40 becomes larger (almost twice the original number). Secondly, some edge speckles in the projected speckle can be located at the center of the receiving field of view, such as spot A2, which was originally a relatively edge point in the speckle projected by the corresponding laser projection module 40, but it is located at the center of the receiving field of view. In this way, the problem of low energy (or low energy density) of edge speckles caused by the relative illumination of the infrared receiving camera is effectively solved.

[0081] Fig.15 yes Fig.13 Another schematic diagram of the spatial distribution of the light spot area projected by the 3D structured light projector is shown in FIG. Fig.13 and Fig.15 As shown, one of the laser projection modules 40 can project a speckle pattern of area 43, and the other laser projection module 40 can project a speckle pattern of area 44. Area 43 can be understood as the central area of ​​the projection field of view, and area 44 can be understood as the edge area of ​​the projection field of view. Exemplarily, the two laser projection modules 40 can be driven to illuminate at intervals, and the two corresponding infrared images can be fused to obtain a final speckle pattern for calculating the depth, and then the depth calculation can be performed. In this process, the driving current of the laser projection module 40 corresponding to area 44 can be set to be greater than or equal to the driving current of the laser projection module 40 corresponding to area 43, so that the energy of the edge area of ​​the projected speckle is higher than the energy of the center area, and the speckle energy of the edge area is higher than the speckle energy projected by a single laser projection module 40, which can also well balance the jitter problem caused by the infrared receiving camera, so that the measurement of the entire imaging field of view is more accurate.

[0082] Based on the same inventive concept, an embodiment of the present invention further provides a 3D structured light module. The 3D structured light module includes an infrared receiving camera and a 3D structured light projector as provided in any one of the embodiments of the present invention. Among them, the 3D structured light projector can project a structured light spot pattern to the target object, and the infrared receiving camera can receive the infrared speckle pattern reflected back by the target object. Therefore, the 3D structured light module provided by the embodiment of the present invention has the corresponding beneficial effects of the 3D structured light projector provided by the embodiment of the present invention, which will not be repeated here. Exemplarily, the 3D structured light module can be an electronic device such as a functional robot, which is not limited by the embodiment of the present invention.

[0083] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A 3D structured light projector, characterized in that: It includes a power supply conversion module, a bucket-type energy storage module, a constant current drive control module and a laser projection module; The power supply conversion module is used to perform voltage boost processing on the external voltage input signal; The bucket-type energy storage module is electrically connected to the power supply conversion module and the constant current drive control module respectively. The bucket-type energy storage module is used to store electric energy when the power supply conversion module is discharged, and release electric energy to the constant current drive control module when the power supply conversion module is charged; by controlling the charging and discharging frequency of the power supply conversion module, a constant boost output signal is provided to the constant current drive control module; wherein the bucket-type energy storage module includes a first capacitor, and the capacitance range of the first capacitor is 1500-5000 μF; The constant current drive control module is electrically connected to the laser projection module, and is used to perform constant current processing on the constant boost output signal to obtain a constant current output signal, and provide the constant current output signal to the laser projection module; wherein the constant current output signal includes a pulse form and a DC form; The laser projection module is used to project a structured light spot pattern onto a target object.

2. The 3D structured light projector according to claim 1, characterized in that: The power supply conversion module includes a DC-DC converter, a first inductor, a first diode, a first resistor and a second resistor; The DC-DC converter comprises a first input terminal, a switch control terminal, a first sampling terminal and an enable control terminal; The first input terminal receives the external voltage input signal, and the first input terminal is electrically connected to one end of the first inductor, the other end of the first inductor is electrically connected to the switch control terminal and the positive electrode of the first diode respectively, the negative electrode of the first diode is electrically connected to one end of the first resistor and the input end of the bucket-type energy storage module respectively, the other end of the first resistor is electrically connected to the first sampling terminal and one end of the second resistor respectively, the other end of the second resistor is grounded, and the output end of the bucket-type energy storage module is electrically connected to the enable control terminal.

3. The 3D structured light projector according to claim 1, characterized in that: The constant current drive control module includes a constant current drive chip, a sampling unit, a first PMOS tube, a first NMOS tube and a second inductor; The constant current driving chip includes a second input terminal, a second sampling terminal, a first switch regulating terminal and a second switch regulating terminal; The second input end is electrically connected to the output end of the bucket-type energy storage module, one end of the sampling unit, and the source of the first PMOS tube, respectively; the second sampling end is electrically connected to the other end of the sampling unit and the positive electrode of the laser projection module, respectively; the negative electrode of the laser projection module is electrically connected to one end of the second inductor, and the other end of the second inductor is electrically connected to the drain of the first PMOS tube and the drain of the first NMOS tube, respectively; the gate of the first PMOS tube is electrically connected to the first switch regulation end, the gate of the first NMOS tube is electrically connected to the second switch regulation end, and the source of the first NMOS tube is grounded.

4. The 3D structured light projector according to claim 3, characterized in that: The constant current drive control module also includes a digital-to-analog conversion modulation unit; the constant current drive chip also includes an analog dimming input terminal; The digital-to-analog conversion modulation unit is electrically connected to the analog dimming input terminal, and is used to convert an external PWM input signal into a preset analog voltage output signal to adjust the amplitude of the constant current output signal.

5. The 3D structured light projector according to claim 4, characterized in that: The digital-to-analog conversion modulation unit includes a second NMOS tube, a third NMOS tube, a third resistor, a fourth resistor, a fifth resistor, a plurality of sixth resistors and a plurality of second capacitors; the digital-to-analog conversion modulation unit also includes a PWM control signal input terminal and an external voltage signal input terminal; The gate of the second NMOS tube is electrically connected to the PWM control signal input terminal, the drain of the second NMOS tube is electrically connected to one end of the third resistor and one end of the fourth resistor respectively, the source of the second NMOS tube is grounded, the gate of the third NMOS tube is electrically connected to the other end of the third resistor, the drain of the third NMOS tube is electrically connected to one end of the fifth resistor, the source of the third NMOS tube is grounded, the other end of the fifth resistor is electrically connected to the other end of the fourth resistor and the external voltage signal input terminal respectively, and each of the sixth resistors is sequentially connected in series between the drain of the third NMOS tube and the analog dimming input terminal, one end of the second capacitor is electrically connected to one end of the sixth resistor, and the other end of the second capacitor is grounded.

6. The 3D structured light projector according to claim 1, characterized in that: The laser projection module includes an array laser and an optical element module; The planar array laser is used to emit a laser beam; The optical element module is located on the propagation path of the laser beam, and is used to perform collimation and diffraction processing on the laser beam to project the structured light spot pattern; Wherein, the planar array laser includes a plurality of light-emitting holes; The minimum spacing between the light-emitting holes is pitch, and 35 μm ≤ pitch ≤ 50 μm; And / or, the oxidation aperture of the light-emitting hole is OA, and 15 μm≤OA≤30 μm; And / or, the effective light emitting area of ​​the planar array laser is S, and 0.35mm 2 ≤S≤1mm 2 .

7. The 3D structured light projector according to claim 6, characterized in that: The optical element module comprises an optical collimation unit and an optical diffraction unit, and the optical collimation unit and the optical diffraction unit are sequentially located on the propagation path of the laser beam; The optical collimation unit is used to collimate the laser beam to obtain a collimated laser beam; The optical diffraction unit is used to perform replication and diffusion processing on the collimated laser beam to obtain the structured light spot pattern; Wherein, the reciprocal of the relative aperture of the optical collimation unit is the F number, and the F number is ≤1.9; And / or, the maximum imaging circle diameter of the optical collimation unit is R, and R ≥ 1 mm; And / or, the focal length of the optical collimation unit is L, and L ≥ 4 mm; And / or, the relative illumination of the optical collimation unit is RI, and RI≥94%.

8. The 3D structured light projector according to claim 7, characterized in that: The optical collimation unit comprises a first lens, a second lens and a third lens on a common optical axis, wherein the first lens, the second lens and the third lens are sequentially located on a propagation path of the laser beam; The refractive index of at least two of the first lens, the second lens and the third lens is greater than 1.6; and / or, the first lens satisfies the condition 0.5<r1<r2<2, wherein r1 represents the radius of curvature of the object side surface of the first lens, and r2 represents the radius of curvature of the image side surface of the first lens; And / or, the second lens satisfies the condition -2<r3<r4<-0.5, wherein r3 represents the radius of curvature of the object side of the second lens, and r4 represents the radius of curvature of the image side of the second lens; And / or, the third lens satisfies the conditions r5<r6<0, and 0.6<r6 / r5<1, wherein r5 represents the radius of curvature of the object side surface of the third lens, and r6 represents the radius of curvature of the image side surface of the third lens.

9. The 3D structured light projector according to claim 8, characterized in that: The first lens, the second lens and the third lens satisfy the condition 1<d23 / d12<2, and f1<f3, wherein d12 represents the distance between the first lens and the second lens, d23 represents the distance between the second lens and the third lens, f1 represents the focal length of the first lens, and f3 represents the focal length of the third lens.

10. The 3D structured light projector according to claim 1, characterized in that: There are two laser projection modules, and the two laser projection modules are electrically connected to the constant current drive control module respectively. The projection spot areas of the two laser projection modules are spliced ​​into a larger spot area.

11. A 3D structured light module, characterized in that: It comprises an infrared receiving camera and a 3D structured light projector as described in any one of claims 1-10.

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