Light transmitting power adjusting method

Abstract

The invention discloses a light emission power adjusting method of an optical detection device. The optical detection device is used for emitting an optical signal for detection. The light emission power adjusting method is used for adjusting the light emission power of an optical signal emitted by an optical detection device, and comprises the following steps: obtaining ambient light information of a scene where the optical detection device is located; determining an adaptive light transmitting power value according to the obtained ambient light information; and adjusting the light emission power of the optical detection device according to the adaptive light emission power value.

Description

[0001] This application is a divisional application of the invention patent application with the application date of September 22, 2021, application number 202111104763.7, and invention name “A method for adjusting optical transmission power”. Technical Field

[0002] The present application relates to the field of photoelectric sensing technology, and more specifically, to a method for adjusting light emission power of an optical detection device. Background Art

[0003] The principle of Time of Flight (TOF) measurement is to calculate the distance of an object, or depth, by measuring the flight time of a light signal in space. Due to its advantages such as long sensing distance, high accuracy and low energy consumption, it is widely used in consumer electronics, unmanned driving, AR / VR and other fields.

[0004] The optical detection device using the TOF principle includes a transmitting module and a receiving module. The transmitting module is used to transmit a light signal into space. The receiving module is used to receive the light signal returned from the object and calculate the distance of the object based on the time required from the transmission to the reception of the light signal.

[0005] However, in order to distinguish the sensing light signal returned by the object from the background noise caused by the ambient light, it is often necessary to let the transmitting module transmit the light signal to the space at a higher transmission power to ensure that enough sensing light signals returned from the object can be received even under relatively harsh ambient light conditions. Therefore, the transmitting module needs to maintain a higher level of light transmission power during operation, which will increase the overall power consumption of the TOF device on the one hand, and shorten the device life of the transmitting module on the other hand. Summary of the invention

[0006] In view of this, the present invention provides a method for adjusting the light emission power of an optical detection device which can improve the problems of the prior art.

[0007] The embodiment of the present application provides a method for adjusting the optical transmission power of an optical detection device, wherein the optical detection device is used to transmit an optical signal for detection. The method for adjusting the optical transmission power is used to adjust the optical transmission power of the optical signal transmitted by the optical detection device, and comprises the following steps:

[0008] Obtaining ambient light information of a scene where the optical detection device is located;

[0009] Determine an adapted light emission power value according to the obtained ambient light information; and

[0010] The light emission power of the optical detection device is adjusted according to the adapted light emission power value.

[0011] In an embodiment of the present invention, the optical detection device is preset with an adjustment lookup table, the adjustment lookup table includes a correspondence between ambient light information and an adapted light emission power value, and the step of determining the adapted light emission power value according to the obtained ambient light information includes the following sub-steps:

[0012] Obtaining ambient light information through light sensing sensors; and

[0013] According to the obtained ambient light information, the light emission power value adapted thereto is read from the adjustment look-up table.

[0014] In an embodiment of the present invention, the step of obtaining ambient light information of the scene where the optical detection device is located includes the following sub-steps:

[0015] The optical detection device receives the light signal and outputs a corresponding sensing signal;

[0016] The optical detection device counts and statistics the sensing signals generated in different time bins of the receiving period to form a statistical histogram;

[0017] Relevant ambient light information is obtained through the statistical histogram.

[0018] In an embodiment of the present invention, the step of determining the adapted light emission power value according to the obtained ambient light information comprises the following sub-steps:

[0019] A relationship between the light emission power of the optical detection device and the ambient light information is preset; and

[0020] The adapted light emission power is obtained according to the above preset relationship and the obtained ambient light information.

[0021] In an embodiment of the present invention, the sensing signal count generated by the received photons of the ambient light forms the noise background in the statistical histogram, a part of the light signal emitted by the optical detection device is reflected back by an object in the space to form a sensing light signal, and the sensing signal count generated by the received photons of the sensing light signal is superimposed on the noise background to form a signal peak in which the sensing signal count is higher than the sensing signal count of the adjacent time bin, and the light signal emitted at the light emission power P in the preset time window t w The sensing signal count average value Ns of the sensing light signal generated within satisfies the relationship (1): Among them, A is a fixed coefficient, P is the light emission power of the light signal, γ is the reflectivity of the object, h represents Planck's constant, c represents the speed of light, λ represents the wavelength of light, M represents the number of photosensitive pixels used for sensing, D is the lens entrance pupil radius, d represents the distance of the object, and θ l is the lens transmittance, θ fis the filter transmittance, ε represents the photon-triggered avalanche probability of the photosensitive pixel, FF represents the fill factor, N is the number of light signal emissions in a detection frame, and the light emission power P of the emitted light signal is adjusted according to the relationship (1) so that the Ns in the formed statistical histogram satisfies the relationship (2): Among them, α is the confidence factor, which represents the credibility of the signal peak being higher than the noise background, σ s+n is the preset time window t w The standard deviation of the sensing signal counts generated by the photons of the internal ambient light and the photons of the sensing light signal, σ n is the preset time window t w The standard deviation of the sensing signal count generated by the photons of the internal ambient light, Nn is the average value of the sensing signal count generated by the sensed photons of the ambient light, Nn is obtained as the ambient light information through the statistical histogram, and the range of the light emission power value P of the adapted light signal is determined by the relationship (1) and the relationship (2).

[0022] In an embodiment of the present invention, the confidence factor α can be adjusted according to the application scenario, and the light emission power value adapted to the ambient light information and the confidence factor α in the current scene is obtained according to the adjusted relationship (1), relationship (2) and the statistical histogram.

[0023] In an embodiment of the present invention, the method may further include the steps of:

[0024] Preset a total value threshold range of the optical detection device;

[0025] Sending at least two groups of optical signals with different optical transmission powers respectively;

[0026] Different statistical histograms are formed correspondingly under different optical signal transmission powers;

[0027] Obtaining actual total values ​​of the sensing signals of all time bins in the statistical histogram;

[0028] Comparing the actual total value of the sensing signal in the statistical histograms respectively obtained under different light emission powers with a preset total value threshold range; and

[0029] According to the comparison result, a light emission power value adapted to the current ambient light information is selected.

[0030] In an embodiment of the present invention, the step of emitting at least two groups of optical signals with different optical transmission powers is specifically: continuously emitting multiple optical signals with a first optical transmission power as a first group of optical signals, and continuously emitting multiple optical signals with a second optical transmission power as a second group of optical signals, wherein the first optical transmission power is greater than the second optical transmission power.

[0031] In an embodiment of the present invention, the step of comparing the actual total value of the sensing signal in the statistical histogram obtained under different optical emission powers with the preset total value threshold range is specifically: comparing the first actual total value measured corresponding to the first group of optical signals and the second actual total value measured corresponding to the second group of optical signals with the preset total value threshold range respectively.

[0032] In an embodiment of the present invention, the step of selecting a light emission power value adapted to the current ambient light information based on the above-mentioned comparison result is specifically: selecting the first light emission power or the second light emission power corresponding to the first actual total value or the second actual total value within a preset total value threshold range as the adapted light emission power.

[0033] In an embodiment of the present invention, if the first actual total value and the second actual total value are both within a preset total value threshold range, the optical transmission power corresponding to the first actual total value and the second actual total value that is closest to the middle value of the total value threshold range is selected as the adapted optical transmission power.

[0034] In an embodiment of the present invention, if the first actual total value and the second actual total value are both within a preset total value threshold range, a smaller second optical transmit power is selected as the adapted optical transmit power.

[0035] The optical emission power adjustment method of the optical detection device provided in the present application can adjust the optical emission power of the emission module according to the ambient light conditions in the scene, so that the emission power of the optical signal can be appropriately reduced in the scene with weak ambient light, thereby reducing the power consumption of the optical detection device, increasing the life of the light source, and improving the stability of the entire system.

[0036] Additional aspects and advantages of the embodiments of the present application will be given in the following description, and some will become apparent from the following description, or will be learned through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of functional modules of an optical detection device provided by an embodiment of the present application applied to an electronic device;

[0038] Figure 2 yes Figure 1 A schematic diagram of functional modules of the optical detection device;

[0039] Figure 3 is a schematic diagram of the relationship between different signals of the optical detection device provided in an embodiment of the present application;

[0040] Figure 4is a schematic diagram of functional modules of an optical device provided by another embodiment of the present application applied to an electronic device;

[0041] Figure 5 is a schematic diagram of functional modules of an optical detection device provided in one embodiment of the present application;

[0042] Figure 6 is a schematic diagram of functional modules of an optical detection device provided by another embodiment of the present application;

[0043] Figure 7 is a schematic structural diagram of an optical detection device provided by an embodiment of the present application applied to an electronic device;

[0044] Figure 8 is a schematic structural diagram of an optical detection device provided by another embodiment of the present application applied to an electronic device;

[0045] Fig. 9 is a statistical histogram of a sensing signal of the optical detection device provided in an embodiment of the present application;

[0046] Fig.10 yes Figure 5 Schematic diagram of the relationship between the signal peak fluctuation and the noise background fluctuation;

[0047] Fig.11 is a schematic diagram of functional modules of an optical detection device provided by another embodiment of the present application;

[0048] Fig.12 is a schematic diagram of a signal peak that satisfies a Gaussian distribution in a statistical histogram of an optical detection device provided in an embodiment of the present application;

[0049] Fig.13 is a schematic diagram of a signal peak showing an avalanche pile-up effect in a statistical histogram of an optical detection device provided in an embodiment of the present application;

[0050] Fig.14 It is a schematic diagram of functional modules of an optical detection device provided in another embodiment of the present application.

[0051] Fig.15 It is a flowchart of the steps of a method for adjusting the light emission power of an optical detection device provided in one embodiment of the present application.

[0052] Fig.16 yes Fig.15 A step-by-step flowchart of an embodiment of step S102 in FIG.

[0053] Fig.17 yes Fig.15 A step-by-step flowchart of an embodiment of step S101 in FIG.

[0054] Fig.18 yes Fig.15 A step-by-step flowchart of another embodiment of step S102 in FIG.

[0055] Fig.19 It is a flowchart of the steps of a method for adjusting the light emission power of an optical detection device provided in another embodiment of the present application. Specific embodiments

[0056] In the specific description of the embodiments of the present application, it should be understood that when a substrate, sheet, layer or pattern is referred to as being "on" or "under" another substrate, another sheet, another layer or another pattern, it may be "directly" or "indirectly" on another substrate, another sheet, another layer or another pattern, or one or more intermediate layers may also exist. For the purpose of clarity, the thickness and size of each layer in the drawings of the specification may be exaggerated, omitted or schematically indicated. In addition, the size of the elements in the drawings does not fully reflect the actual size.

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] The disclosure below provides many different embodiments or examples to implement different structures of the present application. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0059] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0060] Further, described features, structures can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that, without one or more of the specific details, or adopting other structures, components, etc., it is also possible to put the technical scheme of the present application into practice. In other cases, known structures or operations are not shown or described in detail to avoid blurring the present application.

[0061] An embodiment of the present application provides a method for adjusting the optical transmission power of an optical detection device, wherein the optical detection device is used to transmit an optical signal for detection. The optical transmission power adjustment method is used to adjust the optical transmission power of the optical signal transmitted by the optical detection device, and comprises the following steps:

[0062] Obtaining ambient light information of a scene where the optical detection device is located;

[0063] Determine an adapted light emission power value according to the obtained ambient light information; and

[0064] The light emission power of the optical detection device is adjusted according to the adapted light emission power value.

[0065] Optionally, in some embodiments, the optical detection device emits a light signal into space to detect relevant sensing information of an object in space, such as but not limited to: a combination of one or more of the depth information, distance information, proximity information, etc. of the object. The light signal may be, for example, a light pulse with a preset frequency. At least part of the emitted light signal is reflected by an object in space and returned to form a sensing light signal.

[0066] Optionally, in some embodiments, the sensing signal may be an electrical signal. Alternatively, the sensing signal may be other signals, such as a magnetic signal, depending on the photon conversion principle of the receiving module.

[0067] Optionally, the optical signal received by the optical detection device may include the sensed optical signal. The optical signal received by the receiving module may also include other optical signals that are not emitted by the optical detection device or are not reflected by an object, such as photons in ambient light or optical signals emitted by other light sources in the scene except the optical detection device.

[0068] An embodiment of the present application also provides an electronic device, including the optical detection device. The electronic device implements the corresponding function based on the sensing information obtained by the optical detection device. The sensing information is, for example, one or more of the related information such as proximity information, depth information, distance information, etc. of an object in space. Among them, the related information can be used to determine whether there is an object approaching, 3D modeling, face recognition, automatic driving, machine vision, monitoring, drone control, augmented reality (AR) / virtual reality (VR), simultaneous localization and mapping (SLAM) and other fields, and the present application does not limit this. The optical detection device can be, for example, a laser radar, which can be used to obtain depth information or distance information of objects in the scene to assist in realizing automatic driving control of the car.

[0069] Hereinafter, embodiments in which the optical detection device is applied to electronic equipment will be described in detail with reference to the accompanying drawings.

[0070] Figure 1 It is a schematic diagram of functional modules of the optical detection device 10 provided in an embodiment of the present application applied to an electronic device 1 .

[0071] Figure 2 It is a schematic diagram of the functional modules of the optical detection device 10 provided in an embodiment of the present application.

[0072] Reference Figure 1 and Figure 2 , the electronic device 1 includes an optical detection device 10, which is used to measure the object 2 in the space using the principle of light flight time measurement to obtain corresponding information of the object 2, such as but not limited to: one or more of proximity information, depth information, distance information, etc. The electronic device 1 may also include an application module 20, and the application module 20 may implement related functions based on the corresponding sensing information of the object 2 obtained, such as but not limited to: judging whether the object 2 appears within a preset range in front of the electronic device 1 based on the proximity information of the object 2; or controlling the electronic device 1 to avoid obstacles based on the distance information of the object 2; or performing 3D modeling, face recognition, and realizing machine vision based on the depth information of the object 2.

[0073] 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 a light signal into space and receive a sensed light signal reflected by an object 2 in space. The time difference between the emission of the light signal and the reception of the sensed light signal is called the flight time t. The depth information of the object 2 is obtained by calculating the distance traveled by the light signal during the above flight time. Where c is the speed of light.

[0074] Optionally, in some other embodiments, the optical detection device 10 may 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 light signal and the received sensing light signal.

[0075] In the following embodiments of the present application, the optical detection device 10 is mainly described as a DTOF measurement device as an example.

[0076] Optional, such as Figure 2 As shown, the optical detection device 10 includes a transmitting module 12, a receiving module 14, a light sensing sensor 16 and a control module 18. The transmitting module 12 is used to transmit a light signal into space, at least part of the transmitted light signal is reflected back by an object 2 in the space to form a sensing light signal, at least part of the sensing light signal is received by the receiving module 14, and the reflected sensing light signal carries corresponding information of the object 2, such as depth information, distance information, proximity information, etc.

[0077] The emission module 12 includes a light emitting unit 120 and a modulation element 124. The light emitting unit 120 is used to emit a light signal. The modulation element 124 is used to modulate the light signal emitted by the light emitting unit 120 to form a light signal that can be used for sensing and project it into the space. Optionally, the light signal emitted by the emission module 12 is, for example but not limited to, a speckle pattern or a flood beam.

[0078] Optionally, in some embodiments, the modulation element 124 is, for example, a diffuser or a light homogenizer, which is used to homogenize the light signal emitted by the light-emitting unit 120 to form a floodlight beam.

[0079] Optionally, in some embodiments, the modulation element 124 is, for example, a diffractive optical element (DOE), which is used to replicate the light signal emitted by the light emitting unit 120 and expand and arrange it within a preset field of view angle range to form a speckle pattern. The speckle pattern can be regularly arranged, irregularly arranged, or randomly arranged.

[0080] By duplicating the light signal emitted by the light emitting unit 120 through the DOE, the light signal emitted to the object 2 is composed of a plurality of duplicated light signals, which is beneficial to expanding the field of view angle range of the optical detection device 10 and improving the sensing effect.

[0081] Optionally, in some embodiments, the modulation element 124 may be other suitable types of beam modulation elements, such as but not limited to a microlens array, etc., which is not limited in the present application.

[0082] Optionally, in some embodiments, the transmitting module 12 may further include other suitable optical elements, for example, a lens (not shown) is provided on the path of the light signal emitted from the light emitting unit 120, and the lens may be provided between the light emitting unit 120 and the modulating element 124, and is used to collimate or converge the light signal emitted by the light emitting unit 120 before transmitting it to the modulating element 124. The lens may be a combination of multiple single lenses.

[0083] It should be understood that the embodiment of the present application does not specifically limit the wavelength range of the optical signal emitted by the light emitting unit 120. Optionally, the optical signal emitted by the light emitting unit 120 may be, for example, visible light, infrared light, near infrared light, ultraviolet light, etc.

[0084] Optionally, in some embodiments, the light emitting unit 120 may include a single light source or multiple light sources. The multiple light sources may be, for example, a light source array arranged regularly or irregularly. If the light emitting unit 120 is a vertical cavity surface emitting laser (VCSEL for short, also translated as vertical resonant cavity surface emitting laser), the light emitting unit 120 may include a semiconductor substrate and a VCSEL array die composed of multiple VCSEL light sources arranged on the semiconductor substrate.

[0085] Optionally, in some embodiments, the light source of the light emitting unit 120 may be, for example, an edge emitting laser (EEL), a light emitting diode (LED), a laser diode (LD), etc. The edge emitting laser may be a Fabry Perot (FP) laser, a distributed feedback (DFB) laser, and an electro-absorption modulated laser (EML), which is not limited in the embodiments of the present application.

[0086] Optionally, in some embodiments, the receiving module 14 may include an image sensor 140. The image sensor 140, for example, includes a single photosensitive pixel 142 or a pixel array composed of a plurality of photosensitive pixels 142, and the pixel array is used to receive the sensing light signal reflected by the object 2 to obtain relevant sensing information, such as but not limited to the depth information of the object 2.

[0087] Optionally, in some embodiments, the photosensitive pixel 142 is, for example, a single photon avalanche diode (SPAD), an avalanche photodiode (APD), a photodiode, 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.

[0088] Optionally, in some embodiments, the receiving module 14 may further include a readout circuit (not shown) composed of one or more of a signal amplifier, a time-to-digital converter (TDC), an analog-to-digital converter (ADC), etc. connected to the image sensor 140. Optionally, the readout circuit may also be partially or fully integrated in the image sensor 140.

[0089] Optionally, the receiving module 14 may further include a lens unit 144, which may be used to receive the sensing light signal reflected from the object 2, and collimate or converge the sensing light signal and transmit it to the photosensitive pixel 142 on the image sensor 140. The lens unit 144 may be a combination of multiple single lenses.

[0090] Optionally, the optical detection device 10 can detect relevant information based on the time-of-flight principle. The transmitting module 12 and the receiving module 14 are arranged side by side and adjacent to each other, and the distance between the transmitting module 12 and the receiving module 14 can range from 2 millimeters (mm) to 20 mm, for example. It can be understood that in some embodiments, the transmitting module 12 transmits and the receiving module 14 receives both optical signals, and 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 light signals, and the receiving module 14 includes a light incident surface for receiving light signals. 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 incident surface of the receiving module 14 face the same side of the optical detection device 10.

[0091] Optionally, the control module 18 can be used to control the emission of the light emitting unit 120 in the emission module 12, for example, it can be used to control the frequency of the emitted light signal, the position of the light source lit at different times, the light power of the light source, etc. Optionally, in some embodiments, the control module 18 includes an emission control unit 180, and the emission control unit 180 is used to control the light emitting unit 120 to emit a light signal to space at a preset frequency, and the light signal is, for example, a light pulse with a preset frequency.

[0092] like Figure 3 As shown, in some embodiments, the emission control unit 180 can control the light emitting unit 120 to emit a light signal according to an emission control signal with a preset frequency. It can be understood that the emission control signal can be a drive signal applied to the drive circuit of the light emitting unit 120. Optionally, the emission control signal can be a series of control pulse signals, such as a square wave pulse signal. The control pulse signal includes alternating high-level segments and low-level segments. The light emitting unit 120 is controlled to continuously emit light into the space in the high-level segment and stop emitting light in the low-level segment, thereby emitting the corresponding light signal. Thus, within the timing corresponding to the high-level segment, the light emitting unit 120 continuously emits a light signal into the space, and at least part of the light signal can be reflected back from the object 2 in the space.

[0093] It is understandable that the frequency of the optical signal can be set according to the detection range of the optical detection device 10. For example, one emission cycle of the optical signal includes a light-emitting segment and an extinguishing segment, and the light-emitting unit 120 continuously emits the optical signal in the light-emitting segment and stops emitting light in the extinguishing segment. The emission cycle of the optical signal needs to be greater than the maximum flight time corresponding to the detection range, so that the optical signal emitted in one emission cycle can effectively detect the object 2 within the detection range.

[0094] Optionally, in some embodiments, part or all of the functional units of the control module 18 may be integrated into the transmitting module 12 .

[0095] Optionally, in some embodiments, the control module 18 may further include a receiving control unit 182. The receiving control unit 182 may be used to control the receiving module 14 to synchronously turn on the receiving sensor at the start time of each emission cycle of the optical signal to sense the returned photons. Thus, the receiving module 14 has a receiving cycle corresponding to the emission cycle of the optical signal, the start time of the receiving cycle corresponds to the start time of the emission cycle, and the end time of the receiving cycle corresponds to the end time of the emission cycle. Optionally, in some embodiments, the start time of the receiving cycle is synchronized with the start time of the emission cycle, and the end time of the receiving cycle is synchronized with the end time of the emission cycle.

[0096] Specifically, in some embodiments, the receiving control unit 182 is used to control the photosensitive pixel 142 to synchronously start sensing photons at the start of each emission cycle of the light signal. The photosensitive pixel 142 is, for example, a SPAD, which can only sense a single photon in a receiving cycle. Once the SPAD is triggered by a single photon in a receiving cycle, an avalanche effect will be formed to generate a corresponding sensing signal. The SPAD after the avalanche needs to be quenched and reset to restore the bias voltage to above the breakdown voltage so as to sense the photon again in the next receiving cycle. Based on the above characteristics, the SPAD can sense a photon of the returned sensing light signal in a receiving cycle to generate a corresponding sensing signal. It is understandable that the SPAD may not be able to sense photons in a receiving cycle and does not generate a corresponding sensing signal, but regardless of whether the photon can be sensed, the SPAD will be reset before the end of a receiving cycle to restart sensing the received photons at the beginning of the next receiving cycle.

[0097] Optionally, in some embodiments, part or all of the functional units of the control module 18 may be integrated into the receiving module 14 .

[0098] Optionally, the light sensor 16 can be used to sense the ambient light information of the scene where the optical detection device 10 is located, and the ambient light information includes but is not limited to the wavelength, light intensity, color temperature, etc. of the ambient light. One or more different photosensitive channels are arranged on the path of the light sensor receiving the ambient light, and the light sensor 16 includes filters and photoelectric conversion elements corresponding to different photosensitive channels to correspond to the ambient light information of different wavelength ranges in the sensed ambient light. Optionally, the photosensitive channel can include a combination of one or more of the visible light full spectrum channel (Clear), the red light channel (Red), the green light channel (Green), the blue light channel (Blue) and the wide spectrum channel (Wide). The filter of the visible light full spectrum channel transmits light in the visible light band, the filter of the red light channel transmits light in the red light band, the filter of the green light channel transmits light in the green light band, the filter of the blue light channel transmits light in the blue light band, and the filter of the wide spectrum channel transmits light in the visible light and infrared light bands. The light sensor 16 can provide the spectral information of each channel (CRGBW) and obtain the corresponding ambient light information accordingly.

[0099] Optionally, the photosensitive channel of the light sensor 16 may also include an infrared light channel (IR). The light sensor 16 may directly obtain information related to infrared light or near-infrared light in the scene as ambient light information through the infrared light channel. Alternatively, the light sensor 16 may also obtain information related to infrared light or near-infrared light as ambient light information by subtracting information from the full spectrum channel from information obtained from the wide spectrum channel, thereby eliminating the need to set up an infrared light channel.

[0100] Optionally, the control module 18 may further include a power adjustment unit 184, which may be used to adjust the light emission power of the light emitting unit 120. For example, but not limited to, the power adjustment unit 184 may adjust the light emission power of the light emitting unit 120 according to the ambient light information sensed by the light sensor 16, such as the ambient light intensity, so that the emission power of the optical signal is as small as possible while adapting to the ambient light of the current scene.

[0101] Optionally, in some embodiments, the power adjustment unit 184 can adjust the light emission power of the entire light emitting unit 120 by correspondingly changing the light emission power of individual light sources. Alternatively, the power adjustment unit 184 can adjust the light emission power of the entire light emitting unit 120 by changing the number of light sources on the light emitting unit 120 that emit light, for example: starting a smaller number of light sources to work and emit light at a lower light emission power, and starting a larger number of light sources to work and emit light at a higher light emission power.

[0102] Optionally, in some embodiments, the optical detection device 10 is preset with an adjustment lookup table, which includes a correspondence between ambient light information and light emission power values, which can be obtained by calibrating the light emission power adapted to different ambient light scenes of the optical detection device 10. The adjustment lookup table can be set in advance according to the calibration and stored in the storage medium 30 of the optical detection device 10 or the electronic device 1 for reading.

[0103] Optionally, in some embodiments, the ambient light information may be an ambient light intensity value. The adjustment lookup table includes a correspondence between ambient light intensity values ​​and adapted light emission power values, and the light emission power value of the optical detection device 10 adapted thereto may be determined according to the sensed ambient light intensity value. It is understandable that, in some other embodiments, the adjustment lookup table may also include a correspondence between light emission power values ​​and other ambient light information, such as color temperature, wavelength, etc. The power adjustment unit 184 may determine the light emission power value adapted to the scene according to the ambient light information obtained by the light sensing sensor 16 and the correspondence in the adjustment lookup table.

[0104] Optionally, the power adjustment unit 184 can obtain the ambient light intensity value of the scene through the light sensing sensor 16, and then read the adjustment lookup table according to the ambient light intensity value to determine the corresponding adapted light emission power value, and then adjust the light emission power of the light-emitting unit 120 according to the determined light emission power value, so that the emission power of the optical signal can be appropriately reduced in the scene with weak ambient light, thereby reducing the power consumption of the optical detection device 10, increasing the life of the light source, and improving the stability of the entire system.

[0105] In some embodiments, Figure 4 As shown, the light sensing sensor 16 can be integrated on the transmitting module 12. For example, the transmitting module 12 may include a light emitting unit 120, a light sensing sensor 16 and a control module 18. The light emitting unit 120 is used to transmit a light signal to the space, and at least part of the transmitted light signal will be reflected from the object 2 in the space to form a sensing light signal. The light sensing sensor 16 is used to detect ambient light information in the space. The control module 18 adjusts the transmission power of the light signal transmitted by the light emitting unit 120 to the space according to the ambient light information detected by the light sensing sensor 16. Optionally, the light sensing sensor 16 can be packaged together with the light source on the light emitting unit 120 in a package. Alternatively, the light sensing sensor 16 can also be packaged separately from the light source on the light emitting unit 120 to form different individuals.

[0106] In some embodiments, Figure 5As shown, the light sensing sensor 16 can be integrated on the receiving module 14. For example, the receiving module 14 may include an image sensor 140 and a light sensing sensor 16. Optionally, the light sensing sensor 16 and the photosensitive pixels 142 on the image sensor 140 may be formed on the same semiconductor substrate. Alternatively, the light sensing sensor 16 and the photoelectric sensor 140 may be packaged together in a package. Alternatively, the light sensing sensor 16 and the image sensor 140 may be packaged as separate individuals. It can be understood that in these embodiments, the control module 18 may be integrated in the transmitting module 12, or may not be integrated in the transmitting module 12 but be arranged in other parts of the optical detection device 10.

[0107] Optionally, in some embodiments, the light sensor 16 may also be disposed on the electronic device 1 equipped with the optical detection device 10. For example, if the electronic device 1 is a mobile phone, the light sensor 16 may be disposed at the top middle of the front of the mobile phone; or, the light sensor 16 may be disposed on a camera module (not shown) on the back of the mobile phone.

[0108] like Figure 6 As shown, in some embodiments, the electronic device 1 includes a display screen 40, and the light sensor 16 can be arranged below the display screen 40, and the light sensor 16 can sense the ambient light information outside the electronic device 1 through the display screen 40. Further, optionally, the electronic device 1 can also include a fingerprint sensor 50, and the fingerprint sensor 50 is also arranged below the display screen 40 and forms a fingerprint sensing area on the outer surface of the electronic device 1. The fingerprint sensor 50 can detect the fingerprint of the finger in contact with the fingerprint sensing area. The light sensor 16 and the fingerprint sensor 50 are arranged side by side below the display screen 40, and the orthographic projection of the light sensor 16 on the outer surface of the electronic device 1 is located in the fingerprint sensing area. The optical detection device 10 can be arranged side by side with the display screen 40, or it can be arranged below the display screen 40. It can be understood that the electronic device 1 can also include a cover glass 60, and the cover glass 60 can be arranged above or outside the display screen 40. Optionally, in some embodiments, the electronic device 1 is a mobile phone, and the optical detection device 10 can be set in the middle position of the top of the front of the mobile phone; or, the optical detection device 10 can also be set on the camera module (not shown) on the back of the mobile phone.

[0109] like Figure 7As shown, in some embodiments, the electronic device 1 includes an outer cover plate 70, and the light sensor 16 is disposed below the outer cover plate 70, and senses ambient light information outside the electronic device 1 through the outer cover plate 70. Specifically, the electronic device 1 is, for example, a smart door lock, and the outer cover plate 70 is a panel of the smart door lock. The light sensor 16 can be disposed below the panel and sense ambient light information outside the smart door lock through the panel.

[0110] Optionally, in some embodiments, the optical detection device 10 may be disposed below the outer cover plate 70, and the flight time measurement may be performed through the outer cover plate 70. Alternatively, the optical detection device 10 may be disposed side by side with the outer cover plate 70 or may be passed through a through hole provided on the outer cover plate 70, so that the flight time measurement of the external object 2 may be performed directly without passing through the outer cover plate 70.

[0111] It can be understood that if the light sensing sensor 16 can also be set at other positions on the electronic device 1 except the optical detection device 10, optionally, a special interface can be set on the optical detection device 10 to connect with the light sensing sensor 16 in the electronic device 1 to obtain ambient light information, or the optical detection device 10 can also read the ambient light information measured by the light sensing sensor 16 through the microcontroller (Micro-Controller Unit, MCU) on the electronic device 1.

[0112] Optionally, in some embodiments, the optical signal emitted by the light emitting unit 120 is infrared light or near infrared light, and the wavelength range may be: 700nm to 2000nm, for example: 850nm, 905nm, 940nm, 1064nm, 1550nm, etc. The light sensing sensor 16 may be used to sense the light intensity of infrared light or near infrared light in the scene where the optical detection device 10 is located. The power adjustment unit 184 of the control module 18 adjusts the optical signal emission power of the light emitting unit 120 according to the light intensity of infrared light or near infrared light in the sensed scene.

[0113] Optionally, in some embodiments, the optical detection device 10 may further include a processing module 15. The processing module 15 is used, for example, to determine the depth information or distance information of the object based on the time difference between the emission time of the light signal and the sensing time of the sensing light signal. However, it is not limited thereto. In other embodiments, the processing module 15 may also obtain relevant sensing information based on the received sensing light signal and other suitable detection principles.

[0114] Optional, such as Figure 1 As shown, the processing module 15 can be integrated into the optical detection device 10. Alternatively, Figure 8As shown, the processing module 15 may also be disposed at other locations in the electronic device 1 other than the optical detection device 10. For example, the processing module 15 may be a main control module of the electronic device 1, which is not limited in the present application. Figure 1 As shown, the light sensing sensor 16 can be integrated into the optical detection device 10. Alternatively, as shown in Figure 8 As shown, the light sensing sensor 16 may also be disposed at other locations in the electronic device 1 except the optical detection device 10 , and this application does not limit this.

[0115] Please also read Figure 2 , 3 And 9, 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 can divide the receiving cycle into multiple time bins starting from the starting moment, and each time bin corresponds to a preset time interval Δt. Optionally, the time interval Δt corresponding to each time bin is equal. Optionally, the time interval Δt can be the minimum time interval Δt that the TDC can distinguish. It can be understood that the time difference between each time bin and the starting moment of the receiving cycle can be used as a timestamp of the time bin. The timing unit 150 can also be used to calculate the time difference between the moment of the sensing signal generated by the optical signal received by the receiving module 14 within a receiving cycle and the starting moment of the receiving cycle, as a timestamp of the sensing signal.

[0116] Optionally, in some embodiments, the counting unit 152 may be used to perform cumulative counting in a time bin with a corresponding time bin according to the timestamp of the sensing signal, that is, to add one to the number of sensing signals with the same timestamp that have been counted in the time bin. It is understandable that, for an embodiment using SPAD as the photosensitive pixel 142, a photosensitive pixel 142 can only receive a single photon of the light signal and generate a corresponding sensing signal in each receiving cycle, thereby accumulating one in one of the many time bins, or failing to receive any photon and not generating a sensing signal, thereby not accumulating in any time bin.

[0117] It can be understood that the optical signal received by the receiving module 14 may include a sensing light signal emitted from the transmitting module 12 and reflected by the object 2 in the space, and may also include other light signals that are not emitted by the transmitting module 12 or reflected by the object 2, for example: photons of ambient light or light signals emitted by other light sources in the scene other than the transmitting module 12.

[0118] Optionally, in some embodiments, the statistical unit 154 can be used to count the number of sensing signals accumulated in each corresponding time bin in multiple receiving cycles to generate a corresponding statistical histogram. The abscissa of the statistical histogram represents the timestamp of each corresponding time bin, and the ordinate of the statistical histogram represents the accumulated sensing signal count value in each corresponding time bin. Optionally, the statistical unit 154 can be a histogram circuit.

[0119] During the sensing process, a large number of ambient light photons will also be received by the receiving module 14 to generate corresponding sensing signal counts. The probability of these ambient light photons being sensed and leaving counts in each time bin tends to be the same, forming the noise background (Noise Level) of the sensing data. In scenes with high ambient light intensity, the average level of the noise background measured is correspondingly high, and in scenes with low ambient light intensity, the average level of the noise background measured is correspondingly low. On this basis, the photons of the sensing light signal emitted from the transmitting module 12 and reflected by the object 2 are sensed by the receiving module 14, and the corresponding sensing signal counts generated will be superimposed on the noise background, so that the sensing signal counts of the time bin corresponding to the sensed sensing light signal will be significantly higher than the sensing signal counts of other time bins, thereby forming a corresponding signal peak. It can be understood that the counting height of the signal peak will be affected by factors such as the light emission 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 will be affected by factors such as the width of the emitted light signal, the time jitter of the SPAD and TDC, etc. Thus, the timestamp t0 of the time bin corresponding to the signal peak is the flight time of the sensed sensing light signal, which can be used to calculate the depth information or distance information of the object 2. It can be understood that the processing module 15 can also include a sensing information calculation unit 156. The sensing information calculation unit 156 can be used to obtain relevant sensing information of the object 2 in space according to the timestamp t0 of the signal peak determined by the statistical histogram.

[0120] It is understandable that, according to the above sensing principle, the timestamp t0 of the sensed light signal reflected from the object 2 is calculated from the start time of the receiving cycle, that is, from the start time of the light signal emission cycle. Therefore, it is impossible to distinguish the specific moment in the light segment of the emission cycle from which the sensed sensing light signal is emitted, which will cause a certain degree of detection error. The above error can be reduced by shortening the duration of the light segment in the emission cycle. Optionally, in some embodiments, the duration of the light segment in the emission cycle of the light signal can range from 500 picoseconds (picosecond, ps) to 500 nanoseconds (nanosecond, ns), for example, it can be: 500ps, 600ps, 800ps, 1ns, 20ns, 50ns, 100ns, 200ns, etc.

[0121] Optionally, in some embodiments, the light signal emitted by the light emitting unit 120 with the light emission power P is within the preset time window t w The sensing signal count average value Ns of the sensing light signal generated within can be calculated using the following relationship (1):

[0122]

[0123] Among them, A is a fixed coefficient, P is the optical transmission power value of the optical signal, γ is the reflectivity of object 2, h represents Planck's constant, c represents the speed of light, λ represents the wavelength of light, M represents the number of SPADs, D is the lens entrance pupil radius, d represents the distance of object 2, and θ l is the lens transmittance, θ f is the filter transmittance, ε represents the probability of SPAD photons triggering avalanche, FF represents the fill factor, and N is the number of light signal emissions in a detection frame. In order to make the count statistically significant, the number of light signals emitted in a detection frame ranges from tens of thousands to millions.

[0124] The value of the reflectivity γ of the object 2 can be preset. Optionally, the value range of the object reflectivity γ is, for example, 8% to 95%. In some embodiments, the object reflectivity γ can be, for example, 10%.

[0125] The value of the distance d of the object 2 can be preset. Optionally, the object distance d can be the maximum value of the effective distance measurement range calibrated by the optical detection device 10 before leaving the factory. Alternatively, the object distance d can be the initial measurement value of the actual distance of the object currently detected by the optical detection device 10, and the optical detection device 10 can adjust the light emission power value P according to the initial measurement value of the actual distance of the object.

[0126] The photons of ambient light and the photons of the sensing light signal reflected from the object 2 have a certain probability of being received by the photosensitive pixel 142 of the receiving module 14. The type of the photosensitive pixel 142 can be SPAD, and then leave a sensing signal count in the corresponding time bin. The photons of ambient light and the photons of the sensing light signal both satisfy the Poisson distribution as discrete random probability events. Assuming that in each time bin, the mathematical expectation value of the count of the sensed photons of ambient light is Nn, and the mathematical expectation value of the count of the sensed photons of the sensing light signal is Ns, then Nn is the average value of the sensing signal count under the noise background, and Ns is the average value of the sensing signal count when the photons of the sensing light signal are sensed and superimposed on the noise background. Fig.10 As shown, the actual value Nn` of the sensing signal count of the noise background and the actual value Ns` of the sensing signal count of the sensing light signal actually calculated in a single time bin satisfy the Poisson distribution, and there will be a certain range of numerical fluctuations around the average value Nn of the sensing signal count of the noise background and the average value Ns of the sensing signal count of the sensing light signal, respectively. Assume that the standard deviations of the fluctuations are σn and σs, respectively. In order to accurately find the signal peak, the actual value Nn`+Ns` of the sensing signal count of the time bin where the signal peak is located needs to be higher than the actual value Nn` of the sensing signal count of the time bin where the noise background is located in order to be effectively identified. Therefore, it is necessary to make the fluctuation low value of the actual value of the signal peak count (Nn+Ns)-(σ s+n ) can be more likely to be higher than the fluctuation high value of the actual count value of the noise background (Nn+σ n ), according to the above conditions, the optical transmission power P of the optical signal transmitted by the transmitting module 12 can be adjusted according to the relationship (1) so that the Ns in the formed statistical histogram satisfies the relationship (2):

[0127]

[0128] Among them, α is the confidence factor, which represents the credibility of the signal peak being higher than the noise background, σ s+n is the preset time window t w The standard deviation of the count rate of the sensing signal generated by the photons of the internal ambient light and the photons of the sensing light signal, σ n is the preset time window t w The standard deviation of the count rate of the sensing signal generated by the photons of the internal ambient light. Nn is the preset time window t w The average value of the sensing signal counts generated by the photons of the ambient light sensed within the time window, Nn, as the ambient light information, can be obtained through the statistical histogram, and Ns is the preset time window t w Optionally, the preset time window t wIt can be a time interval represented by a time bin or multiple unspecified time bins, and the corresponding average value Nn of the sensing signal count of the noise background can be obtained by calculating the preset time window t w The actual value Nn` of the sensing signal count under the noise background of each of the multiple time bins within is obtained by averaging.

[0129] The higher the light emission power of the optical signal, the higher the average value Ns of the sensed sensing signal count of the sensed sensing optical signal. The higher the intensity of the ambient light, the larger the average value Nn of the sensed sensing signal count of the noise background. It can be seen from the relationship (2) that the light emission power of the adapted optical signal is directly related to the intensity of the ambient light. When the ambient light intensity is greater, the average value Nn of the sensing signal count of the noise background is also greater. If the light emission power of the optical signal remains unchanged, the confidence factor α satisfying the relationship (2) will become smaller, thereby affecting the accuracy of peak finding during the detection process. Therefore, when the ambient light intensity is greater, the optical detection device 10 also needs to increase the light emission power of the optical signal to maintain the signal-to-noise ratio of the statistical histogram. When the light emission power of the light emitting unit 120 is fixed, the light emission power needs to be preset to be larger to meet the harsh scene with greater ambient light intensity. However, this will cause a waste of light emission power in the scene with weak ambient light, and it is also easy to reduce the life of the light source, increase the heat generation of the entire system and the instability of the system.

[0130] Substitute the above relationship (1) into the relationship (2), and then use the statistical histogram obtained by the statistical unit 154 to determine the preset time window t w According to the determined average value Nn of the sensing signal counts of the noise background, the light emission power value range adapted to the ambient light information of the current scene can be obtained through equations (1) and (2). Thus, the power adjustment unit 184 of the control module 18 can adjust the light emission power of the light signal emitted by the light emitting unit 120 according to the adapted light emission power value P obtained above.

[0131] like Fig.11 As shown, in some embodiments, the control module 18 may further include a power calculation unit 186, which is used to obtain a light emission power value P adapted to the ambient light information in the current scene according to the above-mentioned relationship (1), relationship (2) and statistical histogram. It can be understood that in this case, the power calculation unit 186 can obtain the noise background count average Nn representing the ambient light information from the statistical histogram, and the light sensing sensor 16 can be omitted.

[0132] Optionally, in some embodiments, the accuracy of the optical detection device 10 can be adjusted to be suitable for scenarios with different detection accuracy requirements. Optionally, the accuracy of the optical detection device 10 can be reflected by the size of the confidence factor α in the relationship (2). The larger the confidence factor α, the higher the credibility of the measurement result of the optical detection device 10, and the smaller the confidence factor α, the lower the credibility of the measurement result of the optical detection device 10. Therefore, under the premise that other conditions remain unchanged, if the confidence factor α is reduced, the optical emission power of the optical signal is also reduced accordingly, and if the confidence factor α is increased, the optical emission power of the optical signal is also increased accordingly.

[0133] Optionally, in some embodiments, if the confidence factor α is adjusted, the power calculation unit 186 can obtain the light emission power value range that matches the ambient light information and the confidence factor α of the current scene according to the adjusted relationship (1), relationship (2) and the statistical histogram, and the power adjustment unit 184 adjusts the light emission power of the light emitting unit 120 according to the recalculated light emission power value range. Optionally, in some other embodiments, an adjustment lookup table including the relationship between the confidence factor α, the ambient light information and the light emission power value can be preset by calibration, and if the confidence factor α is adjusted, the power adjustment unit 184 can adjust the light emission power of the light emitting unit 120 according to the above adjustment lookup table.

[0134] Optionally, the control module 18 can obtain the ambient light information in the current scene through the statistical histogram, and then determine the corresponding adapted light emission power value according to the ambient light information, and then adjust the light emission power of the light-emitting unit 120 according to the determined light emission power value, so that the light emission power of the optical signal can be appropriately reduced in the scene with weak ambient light, thereby reducing the power consumption of the optical detection device 10, increasing the life of the light source, and improving the stability of the entire system.

[0135] The photons of the sensing light signal reflected from the object 2 satisfy the Gaussian distribution as a discrete random probability event accumulated over time, such as Fig.12 As shown in FIG. 1 , the count values ​​in the time bins on the left and right sides of the signal peak of the statistical histogram satisfying the Gaussian distribution will present a distribution shape that gradually increases toward the signal peak. Since the SPAD can only sense a single photon in one receiving cycle, when the optical detection device 10 is too close to the object 2 or the light emission power is relatively too strong, the return photons with a longer flight time will be submerged by the return photons with a shorter flight time, resulting in an avalanche pile-up effect, such as Fig.13As shown in the figure, a signal peak with a total value significantly higher than the normal level will appear in the statistical histogram, but the count value in the time bin after the signal peak is significantly reduced, thus not satisfying the Gaussian distribution. The avalanche accumulation effect will cause the actual measured statistical histogram to be distorted, and the flight time measurement result will also be smaller. Fig.14 As shown, in some embodiments, the optical detection device 10 may be preset with a total value threshold range, and the control module 18 may also include a comparison unit 188, which may compare the actual total values ​​of all time bins in the statistical histogram with the preset total value threshold range. If the actual total value is greater than the maximum end value of the preset total value threshold range, the light emission power is reduced by the power adjustment unit 184, and if the actual total value is lower than the minimum end value of the preset total value threshold range, the light emission power is increased by the power adjustment unit 184. If the actual total value is within the preset total value threshold range, it means that the current light emission power is appropriate and does not need to be adjusted. It can be understood that in this case, the power adjustment unit 184 of the control module 18 can adjust the light emission power of the light emitting unit 120 according to the judgment result of the comparison unit 188, and the light sensing sensor 16 can be omitted.

[0136] Optionally, in some embodiments, the preset total value threshold range is, for example: (0.008N, 0.5N), where N is the number of receiving cycles for statistics, that is, the number of light signals emitted by the corresponding light-emitting unit 120. It is understandable that, in order to have statistical significance, in an effective detection process, the number of receiving cycles can be, for example, tens of thousands to millions. An effective detection process can also be defined as a detection frame, and the number of light signals continuously emitted by the light-emitting unit 120 in a detection frame corresponds to tens of thousands to millions. It is understandable that the preset total value threshold range can also be other values, such as: (0.01N, 0.1N), (0.007N, 0.4N), (0.02N, 0.6N), etc.

[0137] Optionally, in some embodiments, the control module 18 may also control the light-emitting unit 120 to emit at least two groups of light signals at different light emission powers, for example, to continuously emit multiple light signals at a first light emission power as a first group of light signals, and to continuously emit multiple light signals at a second light emission power as a second group of light signals. The first light emission power is greater than the second light emission power. It is understandable that the at least two groups of light signals may be emitted within one detection frame or may be emitted within different detection frames. The comparison unit 188 of the control module 18 compares the first actual total value measured corresponding to the first group of light signals and the second actual total value measured corresponding to the second group of light signals with a preset total value threshold range, and selects a light emission power adapted to the current ambient light information according to the above comparison result.

[0138] Optionally, in some embodiments, if one of the first actual total value and the second actual total value is within a preset total value threshold range, the power adjustment unit 184 may select the first optical transmission power or the second optical transmission power corresponding to the first actual total value or the second actual total value within the preset total value threshold range as the adapted optical transmission power.

[0139] Optionally, in some embodiments, if the first actual total value and the second actual total value are both within a preset total value threshold range, the power adjustment unit 184 may select the optical transmission power corresponding to the first actual total value and the second actual total value that is closest to the middle value of the total value threshold range as the adapted optical transmission power.

[0140] Optionally, in some embodiments, if the first actual total value and the second actual total value are both within a preset total value threshold range, the power adjustment unit 184 may also select a smaller second optical transmission power as the adapted optical transmission power.

[0141] It can be understood that if the first actual total value and the second actual total value are both outside the preset total value threshold range, the control module 18 can control the light emitting unit 120 to continuously emit multiple optical signals as the third group of optical signals at the third optical transmission power, and to continuously emit multiple optical signals as the fourth group of optical signals at the fourth optical transmission power. The third optical transmission power can be less than the first optical transmission power and greater than the fourth optical transmission power, and the fourth optical transmission power can be greater than the second optical transmission power. The comparison unit 188 of the control module 18 compares the third actual total value measured corresponding to the third group of optical signals and the fourth actual total value measured corresponding to the fourth group of optical signals with the preset total value threshold range, and selects the optical transmission power suitable for the current ambient light information according to the above comparison results. The third actual total value and the fourth actual total value can be selected with reference to the selection method of the first actual total value and the second actual total value, and so on, until at least one actual total value that meets the preset total value threshold range is found, and the corresponding optical transmission power is used as the basis for adjusting the optical transmission power of the light emitting unit 120.

[0142] It can be understood that the selection of the third optical emission power and the fourth optical emission power may depend on the difference between the corresponding measured first actual total value and the second actual total value and the end value of the total value threshold range. If it is larger than the larger end value of the total value threshold range, the corresponding optical emission rate power is adjusted down; if it is smaller than the smaller end value of the total value threshold range, the corresponding optical emission power is adjusted up. In principle, this is to ensure that the measured actual total value is within the preset total value threshold range.

[0143] Optionally, in some embodiments, all or part of the functional units in the control module 18 and / or the processing module 15 may be firmware solidified in the storage medium 30 or computer software code stored in the storage medium 30. The control module 18 and the processing module 15 are executed by one or more corresponding processors (not shown) to control related components to implement corresponding functions. The processors include, but are not limited to, application processors (AP), central processing units (CPU), microcontrollers (MCU), etc. The storage medium 30 includes, but is not limited to, flash memory, electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), hard disk, etc.

[0144] Optionally, in some embodiments, the processor and / or storage medium 30 may be disposed in the optical detection device 10, for example, integrated on the same circuit board as the transmitting module 12 or the receiving module 14. Optionally, in some other embodiments, the processor and / or storage medium 30 may also be disposed at other locations of the electronic device 1, for example, on the main circuit board of a mobile phone.

[0145] Optionally, in some embodiments, some or all of the functional units of the control module 18 and / or the processing module 15 may also be implemented by hardware, for example, by any one of the following technologies or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It is understandable that the above-mentioned hardware for implementing the functions of the control module 18 and / or the processing module 15 may be arranged in the optical detection device 10, for example, integrated on the same circuit board as the photoelectric sensor 140 or the light source. The above-mentioned hardware for implementing the functions of the control module 18 and / or the processing module 15 may also be arranged at other locations of the electronic device 1, for example, on the main board of the mobile phone.

[0146] Compared with the prior art, the optical detection device 10 of the present application can adjust the optical emission power of the optical signal adapted to the current scene, so as to reduce power consumption as much as possible while ensuring the detection effect, extend the service life of the light source, reduce the heat generation of the optical detection device 10, and improve the stability of the optical detection device 10.

[0147] like Fig.15 As shown, the embodiment of the present application also provides a method for adjusting the optical transmission power of an optical detection device 10, wherein the optical detection device 10 is used to transmit an optical signal into space, and obtain relevant sensing information of the object 2 by sensing the sensing optical signal reflected back by the object 2 in the space, such as depth information, distance information, or proximity information. The optical transmission power adjustment method can be used to adjust the optical transmission power of the optical signal transmitted by the optical detection device 10, and the optical transmission power adjustment method includes the following steps:

[0148] Step S101, obtain the ambient light information of the scene where the optical detection device 10 is located. The ambient light information includes but is not limited to the wavelength, light intensity, color temperature, etc. of the ambient light. It is understandable that the part of the ambient light with the same wavelength as the optical signal will interfere with the emitted optical signal. Optionally, in some embodiments, the optical signal is infrared light or near-infrared light, and correspondingly, the ambient light information obtained is the relevant information of the infrared light or near-infrared light part in the ambient light.

[0149] Step S102: determining an adapted light emission power value according to the obtained ambient light information.

[0150] Step S103: adjusting the optical transmission power according to the adapted optical transmission power value.

[0151] Optionally, in some embodiments, the light sensor 16 may be used to obtain the relevant information of the ambient light in step S101. The light sensor may include one or more different photosensitive channels, and the photosensitive channel includes a filter that transmits light of a corresponding wavelength range and a corresponding photoelectric conversion element. Optionally, the photosensitive channel includes one or more of a visible light full spectrum channel (Clear), a red light channel (Red), a green light channel (Green), a blue light channel (Blue) and a wide spectrum channel (Wide). The filter of the visible light full spectrum channel transmits light of the visible light band, the filter of the red light channel transmits light of the red light band, the filter of the green light channel transmits light of the green light band, the filter of the blue light channel transmits light of the blue light band, and the filter of the wide spectrum channel transmits light of the visible light and infrared light bands. The light sensor 16 may provide the spectral information of each of the above channels (CRGBW), and derive the corresponding ambient light information accordingly.

[0152] Optionally, the photosensitive channel of the light sensor 16 may also include an infrared light channel (IR). The light sensor 16 may directly obtain information related to infrared light or near-infrared light in the scene as ambient light information through the infrared light channel. Alternatively, the light sensor 16 may also obtain information related to infrared light or near-infrared light as ambient light information by subtracting information from the full spectrum channel from information obtained from the wide spectrum channel, thereby eliminating the need to set up an infrared light channel.

[0153] Correspondingly, if Fig.16 As shown, in some embodiments, step S102 includes the following sub-steps:

[0154] Step S1021, preset an adjustment lookup table of optical emission power. Specifically, the adjustment lookup table is established by calibrating the optical emission power adapted by the optical detection device 10 in different ambient light scenes, and the adjustment lookup table includes the correspondence between ambient light information and the adapted optical emission power value.

[0155] Step S1022, obtaining ambient light related information through a light sensing sensor. Optionally, the ambient light related information may be the light intensity of the ambient light.

[0156] Step S1023, reading the light emission power value adapted to the ambient light information from the adjustment lookup table according to the obtained ambient light information.

[0157] Optionally, in some embodiments, the ambient light information of the scene can be obtained by forming a statistical histogram in step S101. Fig.17 As shown, in some embodiments, step S101 may include the following sub-steps:

[0158] Step S1011, generating a sensing signal, the optical detection device 10 receives the photons of the ambient light and the photons of the sensing light signal and outputs a corresponding sensing signal. Optionally, the sensing signal may be an electrical signal. Alternatively, the sensing signal may also be other signals, such as a magnetic signal, depending on the conversion principle of the receiving module for photons.

[0159] Step S1012, forming a statistical histogram, the optical detection device 10 counts and counts the sensing signals generated in different time bins of the receiving cycle to form a statistical histogram, and the statistical histogram can be used to obtain the flight time corresponding to the sensing light signal to obtain the relevant sensing information of the object 2. Among them, a large number of ambient light photons will also be received by the receiving module 14 to generate corresponding sensing signal counts, and the probability of these ambient light photons being sensed and leaving counts in each time bin tends to be the same, forming a noise background of the sensing data, and the counts generated by the photons of the sensing light signal are superimposed on the noise background to form a signal peak in which the sensing signal count is higher than the sensing signal count of the adjacent time bin. In a scene with a high ambient light intensity, the average level of the noise background measured is correspondingly higher, and in a scene with a low ambient light intensity, the average level of the noise background measured is correspondingly lower.

[0160] Step S1013, obtain relevant ambient light information through a statistical histogram. Optionally, the ambient light information of the scene can be obtained through the noise background of each time bin in the statistical histogram, for example: the light intensity of the ambient light. The photons of the ambient light and the photons of the sensing light signal both satisfy the Poisson distribution as discrete random probability events. Assuming that in each time bin, the mathematical expectation value of the count of the sensed photons of the ambient light is Nn, and the mathematical expectation value of the count of the sensed photons of the sensing light signal is Ns, then Nn is the count average of the noise background, and Ns is the count average of the effective sensing photons superimposed on the noise background when the photons of the sensing light signal are sensed. Therefore, Nn obtained through the statistical histogram can reflect the ambient light information in the scene where the optical detection device 10 is currently located.

[0161] Correspondingly, if Fig.18 As shown, in some embodiments, step S102 may also include the following sub-steps:

[0162] Step S1024, presetting a relationship between the light emission power of the optical detection device 10 and the ambient light information. Specifically, in some embodiments, the light emission power P of the optical signal is within a preset time window t w The average value Ns of the number of photons generated within the receiving module that can be effectively sensed by the receiving module satisfies the relationship (1): Where A is a fixed coefficient, P is the optical transmission power of the optical signal, γ is the reflectivity of the object, h represents Planck's constant, c represents the speed of light, λ represents the wavelength of light, M represents the number of photosensitive pixels used by the receiving module for sensing, D is the lens entrance pupil radius, d represents the distance of the object, and θ l is the lens transmittance, θ f is the filter transmittance, ε represents the photon-triggered avalanche probability of the photosensitive pixel, FF represents the fill factor, and N is the number of light signal transmissions in a detection frame. The light transmission power P of the transmitted light signal is adjusted so that Ns in the statistical histogram formed satisfies the relationship (2): Among them, α is the confidence factor, which represents the credibility of the signal peak being higher than the noise background, σ s+n is the preset time window t w The standard deviation of the counts of the sensing signal generated by the photons of the internal ambient light and the photons of the sensing light signal, σ n is the preset time window t w The standard deviation of the counts of the sensing signal generated by the photons of the internal ambient light, Nn is the preset time window t w The average count value of the photons of the ambient light sensed within the time window, Nn, can be determined by the statistical histogram, and Ns is the preset time window t w It is understandable that, in other embodiments, other relationship expressions related to the ambient light information and the light emission power may be preset to calculate the adaptive light emission power.

[0163] Step S1025, obtain the light transmission power value adapted to the obtained ambient light information, for example, the adapted light transmission power can be obtained according to the above preset relationship and the obtained ambient light information. Specifically, in some embodiments, the above relationship (1) is substituted into the relationship (2), and then the preset time window t is determined from the statistical histogram. w The count average value Nn of the noise background within the time window can be substituted into the relationship (1) and the relationship (2) to obtain the optical transmission power value range of the adapted optical signal. w It can be the sum of the time intervals represented by one or more unspecified time bins, and the corresponding count average Nn of the noise background can be the time window tw The average value of the actual noise background count Nn.

[0164] Optionally, in some embodiments, the confidence factor α can be adjusted according to the application scenario, and the power calculation unit 186 can obtain the light emission power value range adapted to the ambient light in the current scene according to the adjusted relationship (1), relationship (2) and statistical histogram, and the power adjustment unit 184 adjusts the light emission power of the light emitting unit 120 according to the recalculated light emission power value range. Optionally, in some other embodiments, an adjustment lookup table including the relationship between the confidence factor α, ambient light information and the light emission power value can be preset by calibration. If the confidence factor α is adjusted, the power adjustment unit 184 can adjust the light emission power of the light emitting unit 120 according to the above adjustment lookup table. Therefore, when calculating the adapted light emission power value, step S1025 can be calculated according to the adjusted confidence factor α.

[0165] Optionally, in some embodiments, Fig.19 As shown, the steps may also include:

[0166] Step S100, at least two groups of optical signals are respectively transmitted with different optical transmission powers. For example, a plurality of optical signals are continuously transmitted with a first optical transmission power as a first group of optical signals, and a plurality of optical signals are continuously transmitted with a second optical transmission power as a second group of optical signals. The first optical transmission power is greater than the second optical transmission power.

[0167] Correspondingly, the step S1012 forms corresponding different statistical histograms at different light emission powers. The step S1013 obtains the actual total value of all time bins in the statistical histogram as the ambient light information. Specifically, the actual total value of the corresponding different statistical histograms is obtained as the ambient light information.

[0168] Correspondingly, the step S102 may include the following sub-steps:

[0169] Step S1026 , presetting a total count value threshold range of the optical detection device 10 .

[0170] Step S1027 , comparing the actual total value of the statistical histogram obtained under different optical transmission powers with the preset total value threshold range.

[0171] Step S1028: selecting a light transmission power adapted to the current ambient light information according to the above comparison result.

[0172] It is understandable that the total value threshold range can be preset before the optical detection device 10 leaves the factory.

[0173] Optionally, in some embodiments, a first actual total value measured corresponding to the first group of optical signals and a second actual total value measured corresponding to the second group of optical signals are respectively compared with a preset total value threshold range, and a first optical transmission power or a second optical transmission power corresponding to the first actual total value or the second actual total value within the preset total value threshold range is selected as the adapted optical transmission power.

[0174] Optionally, in some embodiments, a first actual total value measured corresponding to the first group of optical signals and a second actual total value measured corresponding to the second group of optical signals are respectively compared with a preset total value threshold range; if the first actual total value and the second actual total value are both within the preset total value threshold range, the optical transmission power corresponding to the first actual total value and the second actual total value that is closest to the middle value of the total value threshold range is selected as the adapted optical transmission power.

[0175] Optionally, in some embodiments, a first actual total value measured corresponding to the first group of optical signals and a second actual total value measured corresponding to the second group of optical signals are respectively compared with a preset total value threshold range; if the first actual total value and the second actual total value are both within the preset total value threshold range, a smaller second optical transmission power is selected as the adapted optical transmission power.

[0176] It should be understood that the various parts 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, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0177] It should be noted that those skilled in the art can understand that, without paying any creative work, part or all of the embodiments of the present application, as well as part or all of the deformation, replacement, change, splitting, combination, expansion, etc. of the embodiments should be considered to be covered by the inventive ideas of the present application and belong to the protection scope of the present application.

[0178] Any reference in this specification to "one embodiment," "an embodiment," "an example embodiment," etc., indicates that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application. Such phrases appearing in different places in this specification do not necessarily all refer to the same embodiment. In addition, when a particular feature or structure is described in conjunction with any embodiment, it is claimed that it is within the skill of those skilled in the art to implement such feature or structure in conjunction with other embodiments of these embodiments.

[0179] The orientation or positional relationship indicated by "length", "width", "up", "down", "left", "right", "front", "rear", "back", "front", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. that may appear in the specification of this application is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Similar numbers and letters represent similar items in the drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present application, the meaning of "multiple" or "multiple" is at least two or two, unless otherwise clearly and specifically defined. In the description of this application, it is also necessary to explain that, unless otherwise clearly specified and limited, "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0180] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The terms used in the claims should not be understood to limit the invention to the specific embodiments disclosed in this specification. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for adjusting the light emission power of an optical detection device, wherein the optical detection device is used to emit a light signal for detection, characterized in that: The optical transmission power adjustment method is used to adjust the optical transmission power of an optical signal transmitted by an optical detection device, and comprises the following steps: Obtaining ambient light information of a scene where the optical detection device is located; Determine an adapted light emission power value according to the obtained ambient light information; and adjusting the light emission power of the optical detection device according to the adapted light emission power value; The step of obtaining the ambient light information of the scene where the optical detection device is located includes the following sub-steps: The optical detection device receives the light signal and outputs a corresponding sensing signal; The optical detection device counts and statistics the sensing signals generated in different time bins of the receiving cycle to form a statistical histogram; Obtaining relevant ambient light information through the statistical histogram; The step of determining the adapted light emission power value according to the obtained ambient light information comprises the following sub-steps: A relationship between the light emission power of the optical detection device and the ambient light information is preset; and The adapted light emission power is obtained according to the above preset relationship and the obtained ambient light information.

2. The optical transmission power adjustment method according to claim 1, characterized in that: The sensing signal count generated by the received photons of the ambient light forms the noise background in the statistical histogram. A part of the light signal emitted by the optical detection device is reflected back by the object in the space to form a sensing light signal. The sensing signal count generated by the received photons of the sensing light signal is superimposed on the noise background to form a signal peak whose sensing signal count is higher than the sensing signal count of the adjacent time bin. The light signal emitted at the light emission power P is within the preset time window t w The average value N of the sensing signal count of the sensing light signal generated within s Satisfies the relationship (1): Among them, A is a fixed coefficient, P is the light emission power of the light signal, γ is the reflectivity of the object, h represents Planck's constant, c represents the speed of light, λ represents the wavelength of light, M represents the number of photosensitive pixels used for sensing, D is the lens entrance pupil radius, d represents the distance of the object, θ1 is the lens transmittance, θ f is the filter transmittance, ε represents the photon-triggered avalanche probability of the photosensitive pixel, FF represents the fill factor, N is the number of light signal emissions in a detection frame, and the light emission power P of the emitted light signal is adjusted according to the relationship (1) so that the N in the statistical histogram formed is s Satisfies the relationship (2): Among them, α is the confidence factor, which represents the credibility of the signal peak being higher than the noise background, σ s+n is the preset time window t w The standard deviation of the sensing signal counts generated by the photons of the internal ambient light and the photons of the sensing light signal, σ n is the preset time window t w The standard deviation of the sensing signal counts generated by the photons of the internal ambient light, N n is the preset time window t w The average value of the sensing signal counts generated by the photons of ambient light sensed within, N n As the ambient light information is obtained through the statistical histogram, the range of the light emission power value P of the adapted optical signal is determined by equations (1) and (2).

3. The optical transmission power adjustment method according to claim 2, characterized in that: The confidence factor α can be adjusted according to the application scenario, and the light emission power value adapted to the ambient light information in the current scene and the confidence factor α can be obtained according to the adjusted relationship (1), relationship (2) and the statistical histogram.

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