A method for adjusting the emission of optical signals

Abstract

The present application provides a method for adjusting the emission of optical signals, including the following steps: emitting at least two first optical signals; respectively modulating the phases of the first optical signals to obtain corresponding at least two second optical signals and projecting them into space; and adjusting the light concentration degree of the second optical signals on an object according to the detection data obtained in a detection scene to be adapted to the detection scene.

Description

Technical Field

[0001] This application belongs to the technical field of optical detection, and particularly relates to a transmitting module, an optical detection device, and an electronic device. Background Art

[0002] The principle of Time of Flight (TOF) measurement is to calculate the distance of an object by measuring the flight time of an optical signal in space, or in other words, three-dimensional information such as the depth of the object surface. Due to the advantages of long sensing distance, high precision, low energy consumption, etc. of TOF measurement, it is widely used in fields such as consumer electronics, driverless, AR / VR, etc.

[0003] An optical detection device using the TOF principle includes a transmitting module and a receiving module. The transmitting module is used to emit an optical signal into space, and the receiving module receives the carrier-bearing optical signal returned from the object and senses the three-dimensional information of the object according to the time required for the carrier-bearing optical signal to travel from transmission to reception.

[0004] However, currently, the power and phase of the optical signal emitted by the optical detection device are usually fixed and non-adjustable. The emission parameters of the optical signal need to be designed according to the measurement requirements for the farthest distance within the ranging range. This results in a large part of the optical emission power being wasted in the scenario of close-range sensing, which is not conducive to the battery life of the optical detection device and will also shorten the device life of the transmitting module. Summary of the Invention

[0005] In view of this, this application provides a method for adjusting the emission of an optical signal that can improve the problems of the prior art.

[0006] In a first aspect, this application provides a method for adjusting the emission of an optical signal, including the following steps: emitting at least two first optical signals; modulating the phases of the respective first optical signals to obtain corresponding at least two second optical signals and projecting them into space; and adjusting the light concentration of the second optical signals on the object to be adapted to the detection scenario according to the detection data obtained in the detection scenario.

[0007] In an embodiment of the present application, the step of adjusting the light intensity concentration of the second optical signal on an object according to the detection data obtained in the detection scenario to be adapted to the detection scenario includes the following sub-steps: receiving the returned optical signal and outputting a corresponding sensing signal; accumulating and counting the sensing signal within a corresponding time bin to generate a corresponding statistical histogram; comparing the highest sensing signal count value of the highest signal peak in the statistical histogram with a preset count threshold range; when the highest sensing signal count value is less than the first count threshold, controlling the phase modulation of the first optical signal to increase the light intensity concentration of the second optical signal on the object, where the first count threshold is the lower limit value of the count threshold range; when the highest sensing signal count value is greater than the second count threshold, controlling the phase modulation of the first optical signal to decrease the light intensity concentration of the second optical signal on the object, where the second count threshold is the upper limit value of the count threshold range; and when the highest sensing signal count value is within the count threshold range, controlling the phase modulation of the first optical signal to maintain the light intensity concentration of the second optical signal on the object unchanged.

[0008] In an embodiment of the present application, the step of adjusting the light intensity concentration of the second optical signal on an object according to the detection data obtained in the detection scenario to be adapted to the detection scenario further includes the following sub-steps: if the highest sensing signal count value obtained after maximizing the light intensity concentration of the second optical signal projected on the object is still less than the first count threshold, increasing the light emission power of the first optical signal; and if the highest sensing signal count value obtained after minimizing the light intensity concentration of the second optical signal projected on the object is still greater than the second count threshold, decreasing the light emission power of the first optical signal.

[0009] In an embodiment of the present application, it further includes the step of: if the second optical signal is adjusted to project a pattern with a non-uniform light intensity distribution on the object, adjusting the emission direction of the second optical signal to change the position of the bright area of the pattern projected by the second optical signal on the object, so that the bright area of the projected pattern can scan and cover the entire object.

[0010] In an embodiment of the present application, a microelectromechanical system galvanometer or an optical phased array is used to adjust the direction of the emitted second optical signal.

[0011] In an embodiment of the present application, the direction of emitting the second optical signal is adjusted by a mechanical rotation method.

[0012] In an embodiment of the present application, the phase of different light beams in the first optical signal is modulated by a nano-optical chip, a liquid crystal optical phase modulator or an optical waveguide phase modulator.

[0013] In an embodiment of the present application, the phase change amount before and after modulation of each beam of the first optical signal is adjusted to correspondingly change the pattern projected by each beam of the second optical signal on the object. The pattern includes a dot matrix spot pattern, a linear array stripe pattern, or a floodlight pattern. The light concentration degrees of different patterns from high to low are: dot matrix spot pattern, linear array stripe pattern, and floodlight pattern.

[0014] In an embodiment of the present application, the at least two beams of the second optical signal obtained correspondingly are coherent light with each other.

[0015] In an embodiment of the present application, the at least two beams of the second optical signal obtained correspondingly are incoherent light with each other.

[0016] Advantages of the present application:

[0017] Under the condition that the optical emission power remains unchanged, the light concentration degree of the pattern projected by the second optical signal beam on the object is preferentially adjusted by modulating the phase of the first optical signal beam emitted, so that the emitted second optical signal can meet the requirements of different detection scenarios, and the overall power consumption of the optical detection device is reduced.

[0018] Although multiple embodiments, including their variations, are disclosed, other embodiments of the present disclosure will be apparent to those skilled in the art from the following detailed description of the illustrative embodiments of the present disclosure shown and described. It will be recognized that the present disclosure can be modified in various obvious aspects, and all modifications will not depart from the spirit and scope of the present disclosure. Accordingly, the drawings and the detailed description are to be regarded as illustrative in nature and not restrictive. Description of the Drawings

[0019] The features and advantages of the present invention will become more apparent by referring to the accompanying drawings and describing its exemplary embodiments in detail.

[0020] Figure 1 Schematic diagram of the functional modules of an electronic device provided in an embodiment of the present application;

[0021] Figure 2 For Figure 1 Schematic diagram of the functional modules of an embodiment of the optical detection device described in

[0022] Figure 3 For Figure 2 Schematic diagram of the functional modules of an embodiment of the emission module described in

[0023] Figure 4 For Figure 2 Schematic diagram of the functional modules of another embodiment of the emission module described in

[0024] Figure 5 For Figure 2Schematic diagram of the functional modules of another embodiment of the emission module described in

[0025] Figure 6 is Figures 3 - 5 Schematic diagram of the structure of an embodiment of the phase modulation element described in

[0026] Figure 7 is Figure 2 Schematic diagram of the functional modules of an embodiment of the receiving module described in

[0027] Figure 8 is Figure 2 Schematic diagram of the functional modules of an embodiment of the control module described in

[0028] Figure 9 Schematic diagram of the relationship between different signals of the optical detection device provided by the embodiment of the present application

[0029] Figure 10 is Figure 1 Schematic diagram of the functional modules of another embodiment of the optical detection device described in

[0030] Figure 11 Schematic diagram of the functional modules of the electronic device provided by another embodiment of the present application

[0031] Figure 12 is Figure 10 and Figure 11 Schematic diagram of the functional modules of an embodiment of the processing module described in

[0032] Figure 13 Statistical histogram of the optical detection device provided by the embodiment of the present application

[0033] Figure 14 is Figure 1 Schematic diagram of the functional modules of another embodiment of the optical detection device described in

[0034] Figure 15 is Figure 14 Schematic diagram of the structure of another embodiment of the beam scanning element described in

[0035] Figure 16 Flowchart of the steps of the optical signal emission adjustment method provided by an embodiment of the present application

[0036] Figure 17 is Figure 16 Sub - step flowchart of an embodiment of step S103 described in

[0037] Figure 18 Flowchart of the steps of the optical signal emission adjustment method provided by another embodiment of the present application Specific embodiment

[0038] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application. In the description of the present application, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity or arrangement order of the indicated technical features. Thus, the technical features defined with "first" and "second" may explicitly or implicitly include one or more of the described technical features. In the description of the present application, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0039] In the description of the present application, it should be noted that unless otherwise clearly specified or limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a communication with each other; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0040] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, only the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In addition, the present application may reuse reference numerals and / or reference letters in different examples. This reuse is for the purpose of simplifying and clearly presenting the present application and does not itself indicate a specific relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and materials provided in the following description of the present application are only examples for implementing the technical solution of the present application, but those of ordinary skill in the art should realize that the technical solution of the present application can also be implemented by other processes and / or other materials not described below.

[0041] Furthermore, the described features and structures can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to enable a full understanding of the embodiments of the present application. However, those skilled in the art should realize that even without one or more of the specific details, or by using other structures, components, etc., the technical solution of the present application can still be practiced. In other cases, well-known structures or operations are not shown or described in detail to avoid obscuring the key points of the present application.

[0042] Embodiments of the present application provide a method for adjusting the emission of optical signals, including the following steps: emitting at least two first optical signals; modulating the phases of each of the first optical signals to obtain corresponding at least two second optical signals and projecting them into space; and adjusting the light intensity concentration of the second optical signals on an object according to the detection data obtained in the detection scenario to be adapted to the detection scenario.

[0043] Optionally, in some embodiments, the at least two first optical signals and the corresponding at least two second optical signals are coherent light. For example: having the same polarization state, substantially the same frequency or frequency range, and maintaining a stable phase difference during propagation, etc. Thus, the at least two second optical signals can form interference enhancement regions and interference cancellation regions with stable distributions in space. The part of the object located in the interference enhancement region will form a bright region with a higher light intensity. The part of the object located in the interference cancellation region will form a dark region with a weaker light intensity. It can be understood that the distribution positions of the interference enhancement region and the interference cancellation region can be adjusted by changing the initial phases between different beams of the second optical signals, so that the pattern projected by the second optical signals on the object can be correspondingly adjusted. For example: when the position of the object coincides with the positions of the interference enhancement region and the interference cancellation region, the second optical signals can form an alternating bright and dark dot matrix spot pattern or a linear array stripe pattern on the object, that is, in this case, the light intensity projected by the second optical signals on the object is non-uniformly distributed, and the light energy is concentrated in the local region corresponding to the interference enhancement region; when the object is located at a position outside the interference enhancement region and the interference cancellation region, the second optical signals form a floodlight pattern with a uniformly distributed light intensity on the object.

[0044] Optionally, in some other embodiments, the at least two second optical signals can be mutually incoherent light. For example: having different polarization states or the phase difference during propagation changing continuously. Thus, the at least two second optical signals projected into space cannot form interference enhancement regions and interference cancellation regions with stable distributions in space. In this case, the second optical signals form a floodlight pattern with a uniformly distributed light intensity on the object.

[0045] Optionally, in some embodiments, the projected second optical signals can be used to sense sensing information related to the depth information, distance information, proximity information, etc. of an object in space. The second optical signals can be, for example, optical pulses with a preset frequency. Among them, at least part of the emitted second optical signals are reflected by an object in space to form a signal-bearing optical signal. The signal-bearing optical signal can reflect sensing information related to the depth information, distance information, proximity information, etc. of the object, and the relevant sensing information of the object can be obtained by receiving and analyzing the signal-bearing optical signal.

[0046] Embodiments of the present application further provide an optical detection device, which includes a transmitting module, a receiving module, and a processor that use the optical signal emission adjustment method described above. The receiving module is configured to receive an optical signal and output a corresponding sensing signal, and the processing module obtains relevant sensing information according to the sensing signal generated by the receiving module, such as, but not limited to, obtaining one or more of the depth information, distance information, and proximity information of the object.

[0047] Optionally, the optical detection device can perform detection of relevant information based on the time-of-flight principle. The transmitting module and the receiving module are arranged adjacent to each other side by side, and the value range of the distance between the transmitting module and the receiving module can be, for example, 2 millimeters (mm) to 20 mm. It can be understood that in some embodiments, both the optical signal emitted by the transmitting module and the optical signal received by the receiving module are optical signals, and the distance between the transmitting module and the receiving module refers to the distance between the optical axes of their respective optical systems. The transmitting module includes a light-emitting surface that emits an optical signal, and the receiving module includes a light-incident surface that receives an optical signal. When the transmitting module and the receiving module are arranged side by side, the light-emitting surface of the transmitting module and the light-incident surface of the receiving module face the same side of the optical detection device.

[0048] It can be understood that, in addition to the carrier optical signal, the optical signal received by the receiving module may also include other optical signals that are not emitted by the transmitting module or reflected back by an object, such as: optical signals of ambient light or optical signals emitted by other light sources in space, etc.

[0049] Optionally, the sensing signal can be an electrical signal, which is obtained by photoelectric conversion of the received optical signal. Optionally, the sensing signal can also be other types of signals, such as a magnetic signal, depending on the conversion principle of the receiving module for the optical signal.

[0050] Embodiments of the present application further provide an electronic device, which includes the optical detection device. The electronic device realizes corresponding functions according to the sensing information obtained by the optical detection device. The sensing information is, for example, one or more of relevant information such as proximity information, depth information, and distance information of an object in space. Among them, the depth information can be used, for example, in fields such as 3D modeling, face recognition, autonomous driving, machine vision, monitoring, drone control, augmented reality (AR) / virtual reality (VR), simultaneous localization and mapping (SLAM), etc., and the present application does not limit this. The proximity information is used, for example, to determine whether an object is approaching, etc.

[0051] The optical detection device described above can be, for example, a lidar, which can be used to obtain depth information or distance information of objects in space. The lidar is applied, for example, in fields such as intelligent driving vehicles, intelligent driving aircraft, 3D printing, VR, AR, service robots, etc. Taking an intelligent driving vehicle as an example, a lidar is set in the intelligent driving vehicle. The lidar can scan the surrounding environment by quickly and repeatedly emitting laser beams to obtain point cloud data reflecting the morphology, position, and motion of one or more objects in the surrounding environment. Specifically, the lidar emits laser beams to the surrounding environment and receives the echo beams reflected by each object in the surrounding environment. By calculating the time delay (i.e., flight time) between the emission time of the laser beam and the return time of the echo beam, the position information of each object is determined. At the same time, the lidar can also determine the angle information describing the spatial orientation of the laser beam. By combining the position information of each object and the angle information of the laser beam, a three-dimensional map including each object in the scanned surrounding environment is generated, and the intelligent driving of the driverless vehicle can be guided using this three-dimensional map.

[0052] Hereinafter, embodiments in which the optical detection device is applied to an electronic device will be described in detail with reference to the accompanying drawings.

[0053] Figure 1 It is a schematic diagram of the functional modules of the optical detection device 10 provided by an embodiment of the present application applied to the electronic device 1. Figure 2 It is a schematic diagram of the functional modules of the optical detection device 10 provided by an embodiment of the present application.

[0054] Refer to Figure 1 and Figure 2 As shown in FIGS. and, the electronic device 1 includes an optical detection device 10. The optical detection device 10 can detect an object 2 in space to obtain corresponding information of the object 2, such as but not limited to: one or more of the proximity information of the object 2, the depth information of the surface of the object 2, and the distance information of the object 2 in space.

[0055] The electronic device 1 may further include an application module 20. The application module 20 can implement related functions according to the obtained corresponding sensing information of the object 2, such as but not limited to: determining whether an object 2 appears within a preset range in front of the electronic device 1 according to the proximity information of the object 2; or controlling the electronic device 1 to avoid obstacles according to the distance information of the object 2; or implementing 3D modeling, face recognition, machine vision, etc. according to the depth information of the surface of the object 2.

[0056] Optionally, in some embodiments, the optical detection device 10 is, for example, a Direct Time of Flight (DTOF) measurement device. The DTOF measurement device 10 can perform depth information sensing based on the direct time of flight detection principle. For example, the DTOF measurement device 10 can emit an optical signal into space and receive the signal-bearing optical signal formed by reflection from an object 2 in the space. The time difference between the moment when the optical signal is emitted and the moment when the signal-bearing optical signal is received is called the time of flight t. The depth information of the object 2 is obtained by calculating the distance traveled by the optical signal during the above time of flight. Where c is the speed of light.

[0057] Optionally, in some other embodiments, the optical detection device 10 can also be an Indirect Time of Flight (ITOF) measurement device. The ITOF measurement device 10 performs depth information sensing based on the indirect time of flight detection principle. The ITOF measurement device 10 obtains the depth information of the object 2 by calculating the phase difference between the emitted optical signal and the received signal-bearing optical signal.

[0058] In the following embodiments of the present application, the optical detection device 10 is mainly described by taking the DTOF measurement device as an example.

[0059] Optionally, as Figure 2 shown, the optical detection device 10 includes a transmitting module 12, a receiving module 14, and a control module 18. The transmitting module 12 is configured to emit an optical signal into space to detect relevant information of an object in the space. At least part of the optical signals will be reflected back by the object 2 in the space to form a signal-bearing optical signal. The signal-bearing optical signal carries relevant sensing information of the object 2, such as, but not limited to: the depth information of the surface of the object 2, the distance information of the object 2 in the space, the proximity information of the object 2, etc. At least part of the signal-bearing optical signal can be received by the receiving module 14 to obtain the sensing information of the object 2. The receiving module 14 is configured to receive the returned optical signal and output a corresponding sensing signal. The received optical signal includes the optical signal of the ambient light and the signal-bearing optical signal. The sensing signal is converted from the received optical signal.

[0060] Optionally, as Figure 3As shown, in some embodiments, the emission module 12 includes a light-emitting part 120 and a phase modulation element 122. The light-emitting part 120 is configured to emit at least two first optical signals. The phase modulation element 122 is configured to receive the first optical signals and correspondingly output at least two second optical signals. Among them, the phase modulation element 122 obtains the corresponding second optical signals by modulating the phases of the first optical signals. The initial phase of each second optical signal when projected into space depends on the phase change amount of the corresponding first optical signal before and after being modulated by the phase modulation element 122. Thus, the interference situation of the second optical signals in space can be adjusted by the phase modulation of the corresponding first optical signals by the phase modulation element 122. The energy distribution of the second optical signals in space changes correspondingly with the change of the interference situation of the second optical signals in space. For example, for the same preset position in space, if the preset position is located in the interference enhancement area and the interference cancellation area of the second optical signals, the energy distribution of the second optical signals at this preset position will be concentrated in the interference enhancement area. If the interference situation of the second optical signals changes such that the preset position is outside the interference enhancement area and the interference cancellation area of the second optical signals, correspondingly, the energy distribution of the second optical signals at this preset position will change from the non-uniform distribution concentrated in the interference enhancement area to a uniform distribution. It can be understood that on the premise that the optical emission power is the same and the divergence angle of the optical emission is the same, the illumination power density per unit area of the second optical signals when the energy is non-uniformly distributed is greater than that when the energy is uniformly distributed, but the illuminated area of the second optical signals when the energy is non-uniformly distributed is smaller than that when the energy is uniformly distributed.

[0061] Optionally, the light emitting part 120 may include a light emitter 123 and a beam splitting element 125. The light beam emitted by the light emitter 123 is split into at least two first optical signals by the beam splitting element 125. Optionally, the light emitter 123 may be a light source in the form of a Vertical Cavity Surface Emitting Laser (VCSEL, also translatable as vertical resonant cavity surface emitting laser), an Edge Emitting Laser (EEL), a Light Emitting Diode (LED), a Laser Diode (LD), etc. Among them, the edge emitting laser may be a Fabry Perot (FP) laser, a Distributed Feedback (DFB) laser, an Electro-absorption Modulated (EML) laser, etc., and the embodiments of the present application do not limit this. It can be understood that the light emitting part 120 may include only a single light emitter 123, or may include a light emitter array composed of multiple light emitters 123.

[0062] It should be understood that the embodiments of the present application do not specifically limit the wavelength or wavelength band range of the first optical signal emitted by the light emitter 123. Optionally, the optical signal emitted by the light emitter 123 may be, for example, visible light, infrared light, near infrared light, ultraviolet light, etc.

[0063] Optionally, in some embodiments, at least two of the first optical signals are coherent light, for example: having the same polarization state, the same wavelength or wavelength band range, the same initial phase, etc.

[0064] Optionally, in some embodiments, at least two of the first optical signals may be polarized light.

[0065] Optionally, as Figure 4 shown, the light emitting part 120 may further include a collimating element 121. The collimating element 121 may be disposed between the beam splitting element 125 and the phase modulation element 122. The collimating element 121 is configured to collimate the light beams of the first optical signals formed by beam splitting by the beam splitting element 125, so as to reduce the influence on the accuracy of phase modulation caused by the overlapping of different light beams of the first optical signals during propagation. The collimating element 121 is, for example but not limited to, a collimating lens or a collimating lens group.

[0066] Optionally, in some other embodiments, the collimating element 121 may also be omitted, and the light beam emitted by the light emitter 123 is split into at least two first optical signals by the beam splitting element 125 and then directly received by the phase modulation element 122.

[0067] Optionally, as Figure 5 shown, the emission module 12 may further include a beam expanding element 124. The beam expanding element 124 is configured to expand the second optical signal beam output by the phase modulation element 122. For example, in some embodiments, the phase modulation element 122 includes an incident light side 1220 and an output light side 1224. The incident light side 1220 faces the light emitting portion 120 to receive the first optical signal emitted by the light emitting portion 120, and the beam expanding element 124 is disposed on the output light side 1224 of the phase modulation element 122 to expand the second optical signal output by the phase modulation element 122. It can be understood that after the beam expanding element 124 expands the second optical signal beam, the coherence between the beams of the second optical signal can still be maintained without change. After being expanded by the beam expanding element 124, the divergence angle of the beam of the second optical signal increases, so that the irradiation range of the second optical signal is expanded.

[0068] Optionally, in some other embodiments, the beam expanding element 124 may also be omitted. The second optical signal emitted by the phase modulation element 122 may also be directly projected into space without passing through the beam expanding element 124.

[0069] The phase modulation element 122 is configured to be able to modulate the phases of the respective first optical signals to obtain corresponding second optical signals, and the initial phases of the corresponding second optical signals output can be adjusted by changing the phase change amounts of the respective first optical signals.

[0070] Optionally, in some embodiments, the phase modulation element 122 includes at least two optical channels, and each of the first optical signals propagates in a corresponding optical channel. The phase of a light beam is positively correlated with the optical path of the light in the medium. By changing the optical path of the light beam, the phase of the light beam can be adjusted. According to Fermat's principle, the optical path s can be calculated using the following formula:

[0071]

[0072] where m is the number of layers of the optical path passing through a homogeneous medium, n i and l i are the refractive index of the i-th layer of the medium and the length of the optical path, respectively. Thus, the phase modulation element 122 can modulate the phase of the first optical signal beam propagating in the corresponding optical channel by adjusting the optical path length that the first optical signal beam passes through in the corresponding optical channel and / or the refractive index of the corresponding optical path. As Figure 6As shown, in some embodiments, the phase modulation element 122 includes at least a first optical channel 1221, a second optical channel 1222, and a third optical channel 1223. The first optical channel 1221 includes at least three segments of media with refractive indices n11, n12, and n13 respectively. The second optical channel 1222 includes at least three segments of media with refractive indices n21, n22, and n23 respectively. The third optical channel 1223 includes at least three segments of media with refractive indices n31, n32, and n33 respectively.

[0073] Optionally, different optical channels of the phase modulation element 122 are independent of each other, and the light beams propagating in different optical channels do not interfere with each other. For example, in some embodiments, the phase modulation element 122 has the same number of optical channels as the number of light beams of the first optical signal, and each beam of the first optical signal propagates in a corresponding optical channel of the phase modulation element 122 for phase modulation.

[0074] Optionally, in some embodiments, the phase modulation element 122 can change the refractive index of the optical channel through a modulation signal to modulate the phase of the light beam passing through it. For example, the modulation signal can be an electrical signal or a magnetic signal, and the refractive index of the medium of the optical channel is changed by applying an electrical signal or a magnetic signal to the optical channel. It can be understood that the phase modulation element 122 can apply a unified modulation signal to each optical channel to achieve phase modulation. Alternatively, each optical channel can also be divided into multiple segments, and the phase modulation element 122 applies independent modulation signals to each segment on an optical channel respectively to achieve precise control of the modulated phase.

[0075] In an alternative embodiment of the present application, the phase modulation element 122 can be, for example, various different types of optical phase modulators such as a nano-optical chip, a liquid crystal optical phase modulator, and an optical waveguide phase modulator.

[0076] The phase modulation element 122 is configured to receive a modulation control signal and issue a modulation signal to a corresponding optical channel according to the received modulation control signal to control the phase modulation of the light beam propagating in the corresponding optical channel. The light beam of the first optical signal forms the light beam of the second optical signal after being modulated by the phase modulation element 122 and is projected into space. Optionally, in some embodiments, the phase modulation of the first optical signal by the phase modulation element 122 may not change with time, that is, at least within a preset period of time, the phase change amount of the light beam of the first optical signal after being modulated by the phase modulation element 122 is the same, so that the initial phases of the light beams of the second optical signal are the same or maintain a stable phase difference when projected outward. Thus, different light beams of the second optical signal are coherent light with each other and can form a stable interference distribution in space, such as including an interference enhancement region and an interference cancellation region. In this case, if the object 2 is just located at the positions of the interference enhancement region and the interference cancellation region in space, the light beams of the second optical signal will project an interference pattern of light and dark stripes on the object 2.

[0077] It can be understood that by adjusting the phase change amount of the first optical signal modulated by the phase modulation element 122, the interference distribution of the second optical signal in space can be correspondingly changed. For example, the positions, sizes and shapes of the interference enhancement region and the interference cancellation region can be correspondingly changed. Thus, the interference pattern projected by the light beam of the second optical signal on the object 2 also changes accordingly, such as being adjusted from a dot matrix spot pattern to a linear array stripe pattern. The dot matrix spot pattern corresponds to the case where the interference enhancement region is spot-shaped. The linear array stripe pattern corresponds to the case where the interference enhancement region is slender stripe-shaped. The linear array stripe pattern can also be understood as being formed when the adjacent interference enhancement regions are connected to each other to form a slender stripe shape after the interference enhancement region gradually expands from a dot shape. Since the total projected light energy is conserved, the interference distribution of the second optical signal in space will affect the distribution of its light energy density in space. The more concentrated the interference distribution is, the higher the light energy density in the interference enhancement region is, that is, the higher the light power density per unit area is. For example: the light energy distribution of the dot matrix spot pattern is more concentrated than that of the linear array stripe pattern. Thus, on the premise of the same light emission power and the same light emission divergence angle, the light energy density at the spot when projecting the dot matrix spot pattern is higher than the light energy density at the bright stripe when projecting the linear array stripe pattern.

[0078] It can be understood that in some other embodiments, by performing phase modulation on the projected light beam, the emission module 12 can also project other types of patterns on the object 2, not limited to the dot matrix spot pattern and the linear array stripe pattern.

[0079] It can be understood that the interference enhancement regions and interference cancellation regions formed by the second optical signal in space may also be discontinuously distributed, that is, the light waves of different light beams of the second optical signal do not always exactly enhance or cancel each other in space. As a result, the second optical signal will form a floodlight illumination with a uniform light intensity distribution at positions other than the interference enhancement regions and interference cancellation regions, and project a floodlight pattern on the object 2 located at this position. The light energy of the second optical signal is uniformly distributed within the floodlight illumination region, such that the light energy density of the second optical signal within the floodlight illumination region is lower than the light energy density within the interference enhancement region where the light is concentrated. For example: the light energy density of the second optical signal within the floodlight illumination region is lower than the light energy density at the bright fringes when projecting a line array fringe pattern, and even lower than the light energy density at the light spots when projecting a dot matrix light spot pattern.

[0080] The emission module 12 phase-modulates the first optical signal through the phase modulation element 122 to adjust the energy distribution of the projected second optical signal on the object 2. Thus, without increasing the optical emission power, the local illumination power density on the object 2 can be increased by adjusting the energy distribution of the second optical signal on the object 2. For example, the illumination power density at the light spots when the emission module 12 projects a dot matrix light spot pattern on the object 2 is relatively high, the illumination power density at the bright fringes when projecting a line array fringe pattern on the object 2 is the second highest, and the illumination power density within the floodlight illumination region formed on the object 2 is relatively low.

[0081] Optionally, in some other embodiments, the phase modulation of the first optical signal by the phase modulation element 122 may also vary with time, that is, the phase change amount of the light beam of the first optical signal after being modulated by the phase modulation element 122 varies with time, so that the initial phase of the light beam of the second optical signal also continuously varies with time when projecting outward. Thus, different light beams of the second optical signal are mutually incoherent light and cannot form a stable interference distribution in space. In this case, the second optical signal can also form a floodlight illumination with a uniform light intensity distribution in the projection space, thereby being able to project a floodlight pattern on the object 2.

[0082] Optionally, as Figure 7 shown, in some embodiments, the receiving module 14 may include a photoelectric sensor 140. The photoelectric sensor 140 includes, for example, a single photosensitive pixel 142 or a pixel array composed of multiple photosensitive pixels 142. The pixel array is used to receive the carrier optical signal reflected by the object 2 to obtain sensing information related to the object 2, such as but not limited to the depth information of the surface of the object 2, the distance information of the object 2, the proximity information of the object 2, etc.

[0083] Optionally, in some embodiments, the photosensitive pixel 142 may include a single-photon avalanche diode (SPAD), an avalanche photodiode (APD), a silicon photomultiplier (SiPM), and / or other suitable photoelectric conversion elements. For example but not limited to, each photosensitive pixel 142 may include a single SPAD and / or a combination of multiple SPADs.

[0084] Optionally, in some embodiments, the receiving module 14 may further include a readout circuit (not shown in the figure) composed of one or more of devices such as a signal amplifier, a time-to-digital converter (TDC), and an analog-to-digital converter (ADC) connected to the photoelectric sensor 140. Optionally, the readout circuit may also be partially or fully integrated in the photoelectric sensor 140.

[0085] Optionally, the receiving module 14 may further include a lens unit 144, which can be used to collimate or converge the carrier optical signal reflected back from the object 2 and then transmit it to the photosensitive pixel 142 on the photoelectric sensor 140. The lens unit 144 may be a combination of multiple single lenses.

[0086] Optionally, the optical detection device 10 may be used to detect relevant information based on the time-of-flight principle. The transmitting module 12 and the receiving module 14 are arranged adjacent to each other side by side. The value range of the distance between the transmitting module 12 and the receiving module 14 may be, for example, 2 millimeters (mm) to 20 mm. It can be understood that in some embodiments, both the signal transmitted by the transmitting module 12 and the signal received by the receiving module 14 are optical signals. The distance between the transmitting module 12 and the receiving module 14 refers to the distance between the optical axes of their respective optical systems. The transmitting module 12 includes a light-emitting surface for emitting an optical signal, and the receiving module 14 includes a light-receiving surface for receiving an optical signal. When the transmitting module 12 and the receiving module 14 are arranged side by side, the light-emitting surface of the transmitting module 12 and the light-receiving surface of the receiving module 14 face the same side of the optical detection device 10.

[0087] Optionally, the control module 18 may be used to control the situation of the light-emitting part 120 in the transmitting module 12 emitting an optical signal. For example, it can be used to control the wavelength of the emitted optical signal, the position of the light-emitting body 123 that emits light in a time-division manner on the light-emitting part 120, the optical emission power of the light-emitting body 123, etc. Optionally, as Figure 8As shown, in some embodiments, the control module 18 includes a transmission control unit 180 configured to control the transmission module 12 to emit the second optical signal into space at a preset frequency. The second optical signal may be, for example, an optical pulse having a preset frequency.

[0088] Please refer to Figure 8 and Figure 9 , in some embodiments, the transmission control unit 180 may send a transmission control signal to the light emitting part 120 to control the light emitting part 120 to emit an optical signal. It can be understood that the transmission control signal may be a drive signal applied to the drive circuit of the light emitting part 120. Optionally, the transmission control signal may be a series of control pulse signals having a preset frequency, such as a square wave pulse signal. The control pulse signal includes alternately appearing high level segments and low level segments. The light emitting part 120 is lit and continuously emits light into space during the high level segments, and stops emitting light during the low level segments, thereby emitting an optical pulse having a corresponding preset frequency as the first optical signal. The phase modulation element 122 performs phase modulation on the first optical signal and then projects the corresponding second optical signal into space. Thus, within the time sequence corresponding to the high level segments, the transmission module 12 continuously emits the second optical signal into space, and at least part of the second optical signal can be reflected back from the object 2 in space to form the signal-bearing optical signal.

[0089] It can be understood that the emission frequency of the second optical signal can be set according to the detection range of the optical detection device 10. For example: one emission cycle of the second optical signal includes a light emitting segment and an extinguishing segment. The transmission module 12 continuously emits the second optical signal during the light emitting segment and stops emitting light during the extinguishing segment. The emission cycle of the second optical signal needs to be greater than the maximum flight time corresponding to the detection range, so as to enable the second optical signal emitted within one emission cycle to effectively detect the object 2 within the detection range.

[0090] Optionally, in some embodiments, some or all of the functional units of the control module 18 may be integrated in the transmission module 12.

[0091] Optionally, in some embodiments, the control module 18 may further include a reception control unit 182. The reception control unit 182 can be used to control the reception module 14 to synchronously turn on the photoelectric sensor 140 at the start moment of each emission cycle of the second optical signal, so as to sense the returned photons. Thus, the reception module 14 has a reception cycle corresponding to the emission cycle of the second optical signal. The start moment of the reception cycle corresponds to the start moment of the emission cycle, and the end moment of the reception cycle corresponds to the end moment of the emission cycle. Optionally, in some embodiments, the start moment of the reception cycle is synchronized with the start moment of the emission cycle, and the end moment of the reception cycle is synchronized with the end moment of the emission cycle.

[0092] Specifically, in some embodiments, the reception control unit 182 is used to control the photosensitive pixel 142 to synchronously start sensing the returned photons at the start moment of each emission cycle of the second optical signal. The photosensitive pixel 142 is, for example, a SPAD. A SPAD can only sense a single photon within one reception cycle. Once the SPAD is triggered by a single photon within one reception cycle, an avalanche effect will be formed to generate a corresponding sensing signal. After the avalanche, the SPAD needs to be quenched and reset to restore the bias voltage above the breakdown voltage to sense photons again in the next reception cycle. Based on the above characteristics, a SPAD can generate a corresponding sensing signal in response to a returned photon within one reception cycle. It can be understood that the SPAD may not be able to respond to photons within one reception cycle and thus not generate a corresponding sensing signal. However, whether it can respond to photons or not, the SPAD will be reset before the end of one reception cycle to start sensing the received photons again at the beginning of the next reception cycle.

[0093] Optionally, in some embodiments, some or all of the functional units of the control module 18 may be integrated in the reception module 14.

[0094] Optionally, as Figure 10 shown, in some embodiments, the optical detection device 10 may further include a processing module 15. The processing module 15 is, for example, configured to determine the distance information of the object 2 according to the time difference between the emission moment of the second optical signal and the moment when the received carrier optical signal is sensed. However, it is not limited thereto. In other embodiments, the processing module 15 may also obtain relevant sensing information according to the received carrier optical signal and based on other suitable detection principles.

[0095] Optionally, as Figure 11 shown, in some other embodiments, the processing module 15 may also be disposed at other positions in the electronic device 1 other than the optical detection device 10. For example, the processing module 15 may be disposed on the main board of the electronic device 1. The present application does not make any limitation thereto.

[0096] As Figure 12 shown, in some embodiments, the processing module 15 may include a timing unit 150, a counting unit 152, and a statistical unit 154. The timing unit 150 may divide the reception period into a plurality of time bins starting from the start time, where each time bin corresponds to a preset time interval Δt. Optionally, the time intervals Δt corresponding to each time bin are equal. Optionally, the time interval Δt may be the minimum time interval Δt that the TDC can resolve. It can be understood that the time difference between each time bin and the start time of the reception period can be used as the time stamp of the time bin. The timing unit 150 is further configured to calculate the time difference between the moment when the reception module 14 generates a sensing signal in response to the received photons during the reception period and the start time of the reception period, so as to use it as the time stamp of the sensing signal.

[0097] Optionally, in some embodiments, the counting unit 152 is configured to perform cumulative counting within the time bin with the corresponding time stamp according to the time stamp of the sensing signal, that is, add one to the number of sensing signals with the same time stamp that have been counted in the time bin. It can be understood that for embodiments using SPAD as the photosensitive pixel 142, one SPAD can only generate a sensing signal in response to a single photon during each reception period, so it is cumulatively incremented by one in one of the numerous time bins. Or, the SPAD may not receive any photons and thus not generate a sensing signal, so it is not cumulatively counted in any time bin.

[0098] Optionally, as Figure 13 shown, in some embodiments, the statistical unit 154 may be configured to count the number of sensing signals accumulated in each corresponding time bin during a plurality of reception periods to generate a corresponding statistical histogram. Among them, the abscissa of the statistical histogram represents the time stamps of each corresponding time bin, and the ordinate of the statistical histogram represents the count value of the sensing signals accumulated in each corresponding time bin. Optionally, the statistical unit 154 may be a histogram circuit.

[0099] During the sensing process, a large number of photons of ambient light are also received by the receiving module 14, generating corresponding sensing signal counts. The probability that these photons of ambient light are sensed and leave counts in each time bin tends to be the same, constituting the noise background (Noise Level) of the detection scenario. In a scenario with a higher ambient light intensity, the measured average level of the noise background is correspondingly higher; in a scenario with a lower ambient light intensity, the measured average level of the noise background is correspondingly lower. On this basis, the sensing signal counts corresponding to the carrier light signal reflected from the object 2 are superimposed on the noise background, making the sensing signal counts in the time bin corresponding to this carrier light signal significantly higher than those in other time bins, thereby forming corresponding signal peaks. It can be understood that the counting height of the signal peak is affected by factors such as the emission optical power of the light source, the reflectivity of the object 2, and the detection range of the optical detection device 10, and the width of the signal peak is affected by factors such as the width of the emitted optical signal, the time jitter of the SPAD and the TDC. Thus, the time stamp t0 of the time bin corresponding to the highest signal peak with the highest sensing signal count is the flight time of the carrier light signal reflected from the object 2, and the depth information or distance information of the object 2 can be calculated based on this. It can be understood that the processing module 15 may further include a sensing information calculation unit 156. The sensing information calculation unit 156 may be configured to calculate the relevant sensing information of the object 2 in space according to the time stamp t0 of the signal peak determined by the statistical histogram.

[0100] It can be understood that according to the above sensing principle, calculating the time stamp t0 of the carrier light signal reflected from the object 2 starts timing from the start moment of the receiving cycle, that is, from the start moment of the second optical signal emission cycle. Thus, it is impossible to distinguish at which specific moment in the light emission segment of the emission cycle the sensed carrier light signal is emitted, resulting in a certain degree of detection error, which can be reduced by shortening the duration of the light emission segment in the emission cycle. Optionally, in some embodiments, the value range of the duration of the light emission segment in the emission cycle of the second optical signal may be from 500 picoseconds (ps) to 500 nanoseconds (ns), for example, it may be: 500 ps, 600 ps, 800 ps, 1 ns, 20 ns, 50 ns, 100 ns, or 200 ns, etc.

[0101] Photons of the ambient light and photons of the signal-carrying optical signal reflected from the object 2 both have a certain probability of being received by the photosensitive pixels 142 of the receiving module 14, and then leaving a sensing signal count in the corresponding time bin. When the ambient light intensity is high, the noise background level of the sensing signal count in the statistical histogram is also correspondingly high, and the sensing signal count generated by the signal-carrying optical signal reflected from the object 2 is more likely to be submerged in the noise background caused by the ambient light. Therefore, it is necessary to correspondingly increase the light illumination power density of the second optical signal on the object 2 to increase the sensing signal count value generated by the signal-carrying optical signal, so that the signal peak can protrude more obviously from the noise background caused by the ambient light, thereby improving the accuracy and confidence of peak searching in the detection process. However, if the light emission power of the light emitting unit 120 is directly increased, it will increase the power consumption of the optical detection device 10. In this case, as described above, the phase modulation element 122 can be used to modulate the phase of the first optical signal to change the pattern projected by different light beams of the second optical signal on the object 2, so as to increase the light illumination power density of the second optical signal per unit area of the object 2 and increase the sensing signal count generated by the signal-carrying optical signal reflected from the object 2.

[0102] Optionally, in some embodiments, the optical detection device 10 may preset a counting threshold range, which includes a first counting threshold and a second counting threshold. The first counting threshold is the lower limit value of the counting threshold range, and the second counting threshold is the upper limit value of the counting threshold range. If the highest sensing signal count value corresponding to the highest signal peak is less than the first counting threshold, it indicates that the signal-carrying optical signal reflected from the object 2 is insufficient, and it is necessary to increase the light illumination power density of the second optical signal per unit area of the object 2. If the highest sensing signal count value corresponding to the highest signal peak is greater than the second counting threshold, it indicates that the signal-carrying optical signal reflected from the object 2 is redundant, and it is necessary to reduce the light illumination power density of the second optical signal per unit area of the object 2. If the highest sensing signal count value corresponding to the highest signal peak is within the counting threshold range, it indicates that the quantity of the signal-carrying optical signal reflected from the object 2 is appropriate, and the light illumination power density of the second optical signal per unit area of the object 2 can be maintained.

[0103] Correspondingly, as Figure 8As shown, the control module 18 may further include a phase modulation unit 183, which is configured to output a corresponding modulation control signal according to the comparison between the highest sensed signal count value and the count threshold range to control the phase modulation element 122 to modulate the phase of the first optical signal. For example: when the highest sensed signal count value is less than the first count threshold, a first modulation control signal is output, and the phase modulation element 122 is configured to receive the first modulation control signal and output a corresponding modulation signal to modulate the phase of the first optical signal, so as to improve the light illumination concentration of the projected second optical signal on the object 2. When the highest sensed signal count value is greater than the second count threshold, a second modulation control signal is output, and the phase modulation element 122 is configured to receive the second modulation control signal and output a corresponding modulation signal to modulate the phase of the first optical signal, so as to reduce the light illumination concentration of the projected second optical signal on the object 2. It can be understood that the light illumination concentration of the second optical signal on the object 2 can be defined according to the area size of the illuminated area of the second optical signal on the object 2. For example: the smaller the area of the illuminated area, the higher the light illumination concentration and the higher the light power density; the larger the area of the illuminated area, the lower the light illumination concentration and the lower the light power density.

[0104] Optionally, in some embodiments, the light illumination concentrations from high to low may be: dot matrix spot pattern, linear array stripe pattern, and floodlight pattern. It can be understood that the adjustment of the light illumination concentration of the second optical signal projected by the phase modulation element 122 on the object 2 can be carried out across levels. For example, it can be directly switched between the dot matrix spot pattern and the floodlight pattern.

[0105] It can be understood that if the distance of the object 2 is relatively far or the ambient light noise level is relatively high, the second optical signal projected by the emission module 12 on the object 2 will be relatively weak, resulting in insufficient carrier-bearing optical signal reflected back by the object 2. The technical solution provided by the present application can improve the light illumination concentration of the second optical signal on the object 2 through the phase modulation of the phase modulation element 122 without increasing the light emission power of the emission module 12, so as to correspondingly increase the probability that the reflected carrier-bearing optical signal is received by the photosensitive pixel 142 and enhance the signal peak intensity.

[0106] It can be understood that if the distance of the object 2 is relatively close or the ambient light noise level is relatively low, the second optical signal projected by the emission module 12 onto the object 2 will be relatively strong, resulting in a relatively excessive carrier-bearing optical signal reflected back by the object 2. The technical solution provided in this application can reduce the illumination concentration of the second optical signal on the object 2 through the phase modulation of the phase modulation element 122 without changing the optical emission power of the emission module 12, so as to reduce the interference caused by the excessive carrier-bearing optical signal to the detection. At the same time, it can increase the illuminated area of the second optical signal on the object 2 and improve the detection efficiency and frame rate.

[0107] Optionally, in some embodiments, the counting threshold range can be a counting range stored in advance and related to the ambient light noise level, and the ambient light noise level can be embodied as the ambient light intensity, for example. Specifically, a relationship table between the counting threshold range and the ambient light noise level is preset and stored. During detection, the optical detection device 10 senses the ambient light noise level around it and obtains the corresponding counting threshold range according to the ambient light noise level.

[0108] Optionally, in some embodiments, the ambient light noise level can be obtained according to the statistical histogram generated during the detection process. Specifically, during the detection process, the receiving module 14 generates a statistical histogram of the sensed signal counts in response to the photons of the ambient light and the photons of the carrier-bearing optical signal reflected back from the object 2. In addition to the highest signal peak with the highest sensed signal count and a few other time bins with relatively large sensed signal counts in the statistical histogram, the sensed signal counts in most of the time bins are relatively close and the count values are small. The sensed signal counts in these time bins reflect the ambient light noise level. The average value of the sensed signal counts in these time bins or the average value multiplied by a correlation coefficient is used as the ambient light noise level value, and then the corresponding counting threshold range can be obtained accordingly.

[0109] Thus, the phase modulation unit 183 can generate a corresponding modulation control signal according to the currently detected statistical histogram and feedback and output it to the phase modulation element 122, so that the phase modulation element 122 can modulate the second optical signal according to the modulation control signal, realizing an autonomous dynamic adjustment to the optimal emission state that conforms to the actual detection scenario.

[0110] Optionally, in some other embodiments, in addition to being automatically adjusted according to the obtained feedback of the highest sensed signal count value, the modulation control signal can also be manually adjusted through user intervention, so that the emission module 12 projects a second optical signal pattern adapted to the detection scenario on the object 2.

[0111] It can be understood that if the second optical signal emitted by the emission module 12 projects a pattern with a non-uniform light intensity distribution on the object 2, such as a dot matrix light spot pattern or a linear array stripe pattern, the depth information or distance information of the dark area on the object 2 that is not illuminated by the second optical signal cannot be effectively sensed, resulting in a reduction in the sensing accuracy of the object 2. Therefore, as Figure 14 shown, in some embodiments, the optical detection device 10 may further include a beam scanning element 17. The beam scanning element 17 may be configured to adjust the emission direction of the second optical signal so that the bright area positions of the pattern projected by the second optical signal on the object 2 can illuminate different parts of the object 2. Thus, even if the projected pattern has a non-uniform light intensity distribution, the second optical signal can still scan and irradiate different parts of the object 2 to reduce the missing sensing information caused by the lack of the returned carrier optical signal in the parts of the object 2 that are not irradiated by the second optical signal, thereby improving the detection accuracy of the optical detection device 10 for the object 2.

[0112] Optionally, the beam scanning element 17 may adjust the direction of the second optical signal emitted by the emission module 12 in an optical manner. For example, in some embodiments, the beam scanning element 17 may be a micro-electro-mechanical system (MEMS) galvanometer, which may be configured to reflect the second optical signal emitted by the emission module 12 to different angles by deflecting a micro-mirror. Or, in some embodiments, the beam scanning element 17 may be an optical phased array (OPA), which adjusts the propagation angle of the second optical signal by controlling the wavefront direction formed by different light beams in the second optical signal.

[0113] Optionally, as Figure 15 shown, the beam scanning element 17 may also adjust the direction of the second optical signal emitted by the emission module 12 in a mechanical rotation manner. For example, in some embodiments, the beam scanning element 17 is configured as a mechanical structure that drives the emission module 12 to rotate, thereby changing the direction of the second optical signal emitted by the emission module 12. It can be understood that the embodiments of the present application do not limit the rotational degrees of freedom of the beam scanning element 17.

[0114] It can be understood that in some other embodiments, the beam scanning element 17 may also be disposed inside the emission module 12. For example, the emission module 12 includes a light emitting portion 120, a phase modulation element 122, and a beam scanning element 17. The beam scanning element 17 may be disposed on the side where the phase modulation element 122 outputs the second optical signal to optically adjust the emission direction of the second optical signal. Alternatively, the beam scanning element 17 is a mechanical mechanism for rotating the light emitting portion 120 and the phase modulation element 122.

[0115] It can be understood that if the light power density projected by the emission module 12 onto the object 2 does not meet the requirements, and the measured maximum sensing signal count value corresponding to the highest signal peak has exceeded the preset count threshold range, for example: greater than the second count threshold which is the upper limit of the preset count threshold range or less than the first count threshold which is the lower limit of the preset count threshold range. In such a case, the control module 18 may keep the light emission power of the light emitting portion 120 unchanged and preferentially adjust the light concentration projected onto the object 2 through the phase modulation of the phase modulation element 122.

[0116] It can be understood that in some embodiments, after the phase modulation element 122 has maximally adjusted the light concentration projected onto the object 2, the second optical signal emitted still cannot adapt to the detection scenario. For example: the maximum sensing signal count value obtained after the phase modulation element 122 has maximally increased the light concentration of the second optical signal projected onto the object according to the received first modulation control signal is still less than the first count threshold, or the maximum sensing signal count value obtained after the phase modulation element 122 has maximally decreased the light concentration of the second optical signal projected onto the object according to the received second modulation control signal is still greater than the second count threshold. In such a case, the control module needs to adjust the light emission power of the light emitting portion 120 so that the emitted second optical signal adapts to the detection scenario. To this end, as Figure 8 shown, in some embodiments, the control module 18 may further include a power adjustment unit 184, and the power adjustment unit 184 may be configured to adjust the light emission power of the light emitting portion 120. Optionally, the power adjustment unit 184 may adjust the light emission power of the entire light emitting portion 120 by correspondingly changing the light emission power of a single light emitter 123. Alternatively, the power adjustment unit 184 may adjust the light emission power of the entire light emitting portion 120 by changing the number of light emitters 123 that emit light on the light emitting portion 120. For example: when a lower light emission power is required, a smaller number of light emitters 123 are activated to emit light, and when a higher light emission power is required, a larger number of light emitters 123 are activated to emit light.

[0117] Specifically, in some embodiments, when the second light signal projected by the transmitting module 12 forms a dot matrix light spot pattern on the object 2, if the measured highest sensing signal count value is still less than the first counting threshold at the lower limit of the preset counting threshold range, the power adjustment unit 184 outputs a first power adjustment signal, and the light-emitting unit 120 receives the first power adjustment signal to increase the light emission power.

[0118] Similarly, in some embodiments, when the second light signal projected by the transmitting module 12 forms a floodlight pattern on the object 2, if the measured highest sensing signal count value is still greater than the second counting threshold at the upper limit of the preset counting threshold range, the power adjustment unit 184 outputs a second power adjustment signal, and the light-emitting unit 120 receives the second power adjustment signal to reduce the light emission power.

[0119] Therefore, the technical solution provided by the present application can reduce the emission of optical signals that meet the current scene by changing the optical emission power as much as possible under the premise of meeting the detection accuracy requirements. On the one hand, it can reduce the power consumption of the optical detection device 10, and on the other hand, it also provides an emission adjustment method of the emission module 12 that can adapt to more different detection scenes.

[0120] It is understandable that there may be multiple objects 2 at different distances in the space. If the light signal emission state of the entire emission module 12 is adjusted only according to one of the objects 2, it is likely that it cannot be adapted to other objects 2 at different distances. To this end, in some embodiments, the emission module 12 may include multiple light-emitting units 120, which correspond to multiple objects 2 at different distances in the space. Each light-emitting unit 120 projects multiple beams of the second light signal to the corresponding object 2. The emission of different light-emitting units 120 can be independently controlled, so that the parameters such as the light emission power, initial phase, and emission frequency of each light-emitting unit 120 projecting the second light signal can be adjusted in the aforementioned manner, so that each light-emitting unit 120 can meet the detection requirements related to the environment and the distance of the corresponding object 2. Optionally, in some other embodiments, if the emission module 12 includes only one uniformly controlled light-emitting unit 120, the optical detection device 10 can also adjust the emission of the light-emitting unit 120 for objects 2 at different distances in the space in turn and perform corresponding information detection.

[0121] Combination of the above Figures 1 to 14 , describes in detail the device embodiment of the present application, and the following is combined with Figure 15 , Figure 16 and Figure 17 The method embodiment of the present application is described in detail. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment, so the contents not described in detail can refer to the description of the previous device embodiment.

[0122] Figure 15 It shows a method for adjusting the emission of an optical signal provided by an embodiment of the present application, which can be used to adjust the optical signal emission mode of the optical detection device 10. The optical detection device 10 is configured to emit an optical signal into space and obtain relevant sensing information of the object 2 by sensing the carrier optical signal reflected by the object 2 in space, such as depth information, distance information, or proximity information, etc. The method for adjusting the emission of the optical signal can be used to adjust the way the optical detection device 10 emits the optical signal, and the method for adjusting the emission of the optical signal includes the following steps:

[0123] Step S101: Emit at least two first optical signals. The first optical signal can be, for example, visible light, infrared light, near-infrared light, or ultraviolet light, etc. Optionally, in some embodiments, at least two of the first optical signals can be coherent light with each other, for example: having the same polarization state, the same wavelength or wavelength band range, and the same initial phase. Optionally, in some embodiments, at least two of the first optical signals can also be incoherent light. Optionally, in some embodiments, at least two of the first optical signals can be polarized light.

[0124] Optionally, in some embodiments, the at least two first optical signals can be obtained by splitting a single light beam by a beam splitting element 125.

[0125] Step S102: Modulate the phases of the respective first optical signals to obtain corresponding at least two second optical signals and project them into space.

[0126] It can be understood that by adjusting the phase change amount before and after modulation of each first optical signal, the pattern projected by each second optical signal on the object can be correspondingly changed. The pattern includes a dot matrix spot pattern, a linear array stripe pattern, or a floodlight pattern. The light intensity concentrations of different patterns are different, from high to low are: dot matrix spot pattern, linear array stripe pattern, and floodlight pattern. It can be understood that the adjustment of the light intensity concentration of the second optical signal projected on the object 2 can be carried out across levels, for example, it can be directly switched between the dot matrix spot pattern and the floodlight pattern.

[0127] Thus, without changing the optical emission power of the first optical signal, by adjusting the phase change amount before and after modulation of each first optical signal, the light intensity concentration of the pattern projected by the second optical signal beam on the object can be correspondingly adjusted, so that the emitted second optical signal can meet the requirements of different detection scenarios and reduce the overall power consumption of the optical detection device.

[0128] Optionally, in some embodiments, the phase change amount of the corresponding light beam can be adjusted by changing the optical path of the light beam. According to Fermat's principle, the optical path s can be calculated using the following formula:

[0129]

[0130] where m is the number of layers that the optical path passes through the homogeneous medium, and n i and l i are respectively the refractive index of the i-th layer of the medium and the length of the optical path. Thus, the phase of the first optical signal can be modulated by adjusting the lengths of the optical paths that each beam of the first optical signal passes through and / or the refractive indices of the corresponding optical paths.

[0131] Optionally, in some embodiments, the modulation of the phases of at least two beams of the first optical signal may not change with time, that is, the phase change amounts of the beams of the first optical signal after modulation are the same at least within a preset period of time, so that the initial phases of the beams of the second optical signal are the same or maintain a stable phase difference when projecting outward. Thus, the at least two beams of the second optical signal obtained correspondingly are coherent light with each other and can form a stable interference distribution in space, such as including stable interference enhancement regions and interference cancellation regions. In this case, if the object 2 is just located at the positions where the interference enhancement regions and the interference cancellation regions are located in space, the beams of the second optical signal will project an interference pattern of light and dark on the object 2.

[0132] Optionally, in some other embodiments, the modulation of the phases of at least two beams of the first optical signal may also change with time, that is, the phase change amounts of the beams of the first optical signal after modulation change with time, so that the initial phases of the beams of the second optical signal also change with time when projecting outward. Thus, the at least two beams of the second optical signal obtained correspondingly are non-coherent light with each other and cannot form a stable interference distribution in space. In this case, the second optical signal forms a floodlight illumination with a uniform light intensity distribution in the projection space, so as to be able to project a floodlight pattern on the object 2.

[0133] Optionally, in some embodiments, the phases of different beams in the first optical signal can be modulated by various different types of optical phase modulators such as nano-optical chips, liquid crystal optical phase modulators, and optical waveguide phase modulators.

[0134] Step S103, adjust the light concentration of the second optical signal on the object according to the detection data obtained in the detection scene to be adapted to the detection scene. Optionally, the light concentration of the second optical signal on the object can be adjusted by controlling the phase modulation of each beam of the first optical signal.

[0135] As Figure 16 shown, in some embodiments, the step S103 may include the following sub-steps:

[0136] Step S1031, receive the returned optical signal and output a corresponding sensing signal, where the sensing signal is converted from the received optical signal. At least a part of the second optical signal projected into the space is reflected by an object in the space to form a returned signal-bearing optical signal. The signal-bearing optical signal carries relevant sensing information of the object 2, such as but not limited to: depth information of the surface of the object 2, distance information of the object 2 in the space, proximity information of the object 2, etc. The received optical signal includes photons of ambient light and photons of the signal-bearing optical signal.

[0137] Step S1032, accumulate and count the sensing signals within the corresponding time bin to generate a corresponding statistical histogram.

[0138] The reception period of the optical signal corresponds to the emission period of the second optical signal. Optionally, in some embodiments, the start time of the reception period is synchronized with the start time of the emission period, and the end time of the reception period is synchronized with the end time of the emission period. Divide the reception period into multiple time bins starting from the start time, where each time bin corresponds to a preset time interval Δt. Optionally, the time intervals Δt corresponding to each time bin are equal. Optionally, the time interval Δt is the minimum time interval Δt that the TDC can resolve. It can be understood that the time difference between each time bin and the start time of the reception period can be used as the time stamp of the time bin.

[0139] Calculate the time difference between the moment when the sensing signal is generated in response to the received optical signal during the reception period and the start time of the reception period, and use it as the time stamp of the sensing signal. Accumulate and count according to the time stamp of the sensing signal in the time bin with the corresponding time stamp, that is, add one to the number of sensing signals with the same time stamp that have been counted in the time bin.

[0140] It can be understood that, in some embodiments, the SPAD acts as the photosensitive pixel 142 to receive the returned optical signal and output the corresponding sensing signal. A single SPAD can only respond to a single photon to generate a sensing signal during each reception period, so it accumulates and adds one in one of the many time bins. Or, the SPAD may not receive any photons and thus does not generate a sensing signal, so it does not accumulate in any time bin.

[0141] Statistically count the number of sensing signals accumulated in each corresponding time bin during multiple reception periods to generate a corresponding statistical histogram. In the statistical histogram, the time bin corresponding to the moment when the signal-bearing optical signal is sensed becomes the highest signal peak with the highest sensing signal count value.

[0142] Step S1033, compare the highest sensed signal count value of the highest signal peak in the statistical histogram with a preset count threshold range.

[0143] Optionally, in some embodiments, the count threshold range may be a count range pre-stored and related to the ambient light noise level, and the ambient light noise level may be embodied as, for example, the ambient light intensity. Specifically, a relationship table between the count threshold range and the ambient light noise level is preset and stored. During detection, the optical detection device 10 senses the ambient light noise level around it and obtains the corresponding count threshold range according to the ambient light noise level.

[0144] Optionally, in some embodiments, the ambient light noise level may be obtained from the statistical histogram generated during the detection process. Specifically, during the detection process, the receiving module 14 generates a statistical histogram of the sensed signal counts in response to the photons of the ambient light and the photons of the carrier signal light reflected from the object 2. Except for the highest signal peak with the highest sensed signal count and a few other time bins with relatively high sensed signal counts in the statistical histogram, the sensed signal counts in most of the time bins are relatively close and the count values are small. The sensed signal counts in these time bins reflect the ambient light noise level. Take the average of the sensed signal counts in these time bins or multiply the average by a correlation coefficient as the ambient light noise level value, and then the corresponding count threshold range can be obtained accordingly.

[0145] Step S1034, when the highest sensed signal count value is less than the first count threshold, control the phase modulation of the first optical signal to increase the light illumination concentration of the second optical signal on the object, where the first count threshold is the lower limit value of the count threshold range.

[0146] It can be understood that if the distance of the object 2 is relatively far or the ambient light noise level is relatively high, the second optical signal projected on the object 2 will be relatively weak, resulting in insufficient carrier signal light reflected from the object 2. The technical solution provided by the present application can increase the light illumination concentration of the second optical signal on the object 2 by modulating the phase of the first optical signal without increasing the optical emission power of the second optical signal, so as to correspondingly increase the probability that the reflected carrier signal light is received by the photosensitive pixel 142 and enhance the signal peak intensity.

[0147] Step S1035, when the highest sensed signal count value is greater than the second count threshold, control the phase modulation of the first optical signal to reduce the light illumination concentration of the second optical signal on the object, where the second count threshold is the upper limit value of the count threshold range.

[0148] It can be understood that if the distance of the object 2 is relatively close or the ambient light noise level is relatively low, the second light signal projected onto the object 2 will be relatively strong, resulting in a relatively excessive carrier-bearing optical signal reflected back by the object 2. The technical solution provided in this application can reduce the illumination concentration of the second light signal on the object 2 by phase modulating the first light signal without changing the optical emission power of the emission module 12, so as to reduce the interference caused by the excessive carrier-bearing optical signal to the detection. At the same time, it can increase the illuminated area of the second light signal on the object 2 and improve the detection efficiency and frame rate.

[0149] Step S1036, when the highest sensed signal count value is within the counting threshold range, control the phase modulation of the first light signal to keep the illumination concentration of the second light signal on the object unchanged.

[0150] Step S1037, if the highest sensed signal count value obtained after maximizing the illumination concentration of the second light signal projected onto the object is still less than the first counting threshold, increase the optical emission power of the first light signal.

[0151] Specifically, in some embodiments, when the second light signal projects a dot matrix light spot pattern on the object 2, if the measured highest sensed signal count value is still less than the first counting threshold which is the lower limit of the pre-designed counting threshold range, increase the optical emission power of the first light signal.

[0152] Step S1038, if the highest sensed signal count value obtained after minimizing the illumination concentration of the second light signal projected onto the object is still greater than the second counting threshold, decrease the optical emission power of the first light signal.

[0153] Specifically, in some embodiments, when the second light signal projects a floodlight pattern on the object 2, if the measured highest sensed signal count value is still greater than the second counting threshold which is the upper limit of the pre-designed counting threshold range, decrease the optical emission power of the first light signal.

[0154] Optionally, as Figure 17 shown, in some embodiments, the optical signal emission adjustment method further includes the steps:

[0155] Step S104, if the second light signal is adjusted to project a pattern with a non-uniform light intensity distribution on the object 2, adjust the emission direction of the second light signal to change the position of the bright area of the pattern projected by the second light signal on the object, so that the bright area of the projected pattern can scan and cover the entire object.

[0156] Optionally, in some embodiments, the direction of the emitted second optical signal may be adjusted optically. For example, in some embodiments, a microelectromechanical system (MEMS) galvanometer is used to reflect the second optical signal to different angles. Alternatively, an optical phased array (OPA) is used to adjust the propagation angle of the second optical signal by controlling the direction of the wavefront formed by different light beams in the second optical signal.

[0157] Optionally, in some embodiments, the direction of the emitted second optical signal may also be adjusted by mechanical rotation. For example, a rotating mechanism is used to drive the emission module 12 that emits the second optical signal to rotate to change the direction of the emitted second optical signal. It can be understood that the embodiments of the present application do not limit the degrees of freedom of rotation.

[0158] It should be understood that each part of the embodiments of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in the storage medium 30 and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits with logic gate circuits for implementing logic functions on data signals, application-specific integrated circuits with suitable combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0159] It should be noted that those skilled in the art can understand that, without creative efforts, part or all of the embodiments of the present application, as well as the deformations, substitutions, changes, splits, combinations, expansions, etc. of part or all of the embodiments, should be considered to be covered by the inventive concept of the present application and belong to the protection scope of the present application.

Claims

1. A method for adjusting the emission of an optical signal, characterized in that, It includes the following steps: Emit at least two first optical signals; Modulate the phases of the respective first optical signals to obtain corresponding at least two second optical signals and project them into space; And Adjust the light concentration of the second optical signal on the object according to the detection data obtained in the detection scene to be adapted to the detection scene; Among them, the step of adjusting the light concentration of the second optical signal on the object according to the detection data obtained in the detection scene to be adapted to the detection scene includes the following sub-steps: Receive the returned optical signal and output a corresponding sensing signal; Accumulatively count the sensing signal within the corresponding time bin to generate a corresponding statistical histogram; compare the highest sensing signal count value of the highest signal peak in the statistical histogram with a preset count threshold range; When the highest sensing signal count value is less than the first count threshold, control the phase modulation of the first optical signal to increase the light concentration of the second optical signal on the object, where the first count threshold is the lower limit value of the count threshold range; When the highest sensing signal count value is greater than the second count threshold, control the phase modulation of the first optical signal to reduce the light concentration of the second optical signal on the object, where the second count threshold is the upper limit value of the count threshold range; and when the highest sensing signal count value is within the count threshold range, control the phase modulation of the first optical signal to keep the light concentration of the second optical signal on the object unchanged.

2. The method for adjusting the emission of an optical signal according to claim 1, characterized in that, The step of adjusting the light concentration of the second optical signal on the object according to the detection data obtained in the detection scene to be adapted to the detection scene further includes the following sub-steps: If the highest sensing signal count value obtained after maximizing the light concentration of the second optical signal projected on the object is still less than the first count threshold, increase the light emission power of the first optical signal; and If the highest sensing signal count value obtained after minimizing the light concentration of the second optical signal projected on the object is still greater than the second count threshold, reduce the light emission power of the first optical signal.

3. The method for adjusting the emission of an optical signal according to claim 1, characterized in that, It further includes the step: if the second optical signal is adjusted to project a pattern with a non-uniform light intensity distribution on the object, then adjust the emission direction of the second optical signal to change the position of the bright area of the pattern projected by the second optical signal on the object, so that the bright area of the projected pattern can scan and cover the entire object.

4. The method for adjusting the emission of an optical signal according to claim 3, characterized in that, Use a microelectromechanical system galvanometer or an optical phased array to adjust the direction of the projected second optical signal.

5. The method for adjusting the emission of an optical signal according to claim 3, characterized in that, Use a mechanical rotation method to adjust the direction of the projected second optical signal.

6. The method for adjusting the emission of an optical signal according to claim 1, characterized in that, Modulate the phases of different beams in the first optical signal through a nano-optical chip, a liquid crystal optical phase modulator or an optical waveguide phase modulator.

7. The method for adjusting the emission of an optical signal according to claim 1, characterized in that, By adjusting the phase change amount before and after the modulation of each first optical signal, correspondingly change the patterns projected by each second optical signal on the object. The patterns include dot matrix spot patterns, linear array stripe patterns or floodlight patterns. The light concentration of different patterns from high to low is: dot matrix spot patterns, linear array stripe patterns and floodlight patterns.

8. The method for adjusting the emission of an optical signal according to claim 1, characterized in that, The corresponding at least two second optical signals are coherent light with each other.

9. The method for adjusting the emission of an optical signal according to claim 1, characterized in that, The obtained at least two second optical signals are mutually incoherent light.

Images