A method of optical transmit power adjustment

Abstract

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

Description

[0001] This application is a divisional application of the invention patent application filed on September 22, 2021, with application number 202111104763.7 and invention title "A Method for Adjusting Light Emission Power". Technical Field

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

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

[0004] An optical detection device utilizing the Time-of-Flight (TOF) principle includes a transmitting module and a receiving module. The transmitting module emits light signals into space. The receiving module receives light signals reflected from an object and calculates the distance to the object based on the time required for the light signal to travel from emission to reception.

[0005] However, in order to distinguish the sensor light signal returned by an object from the background noise caused by ambient light, the transmitting module often needs to emit light signals into space at a high transmission power to ensure that enough sensor light signals returned by the object can be received even under relatively harsh ambient light conditions. Therefore, the transmitting module needs to maintain a high level of light transmission power during operation, which increases the overall power consumption of the TOF device and shortens the device lifespan of the transmitting module. 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 that can improve the problems of the prior art.

[0007] This application provides a method for adjusting the optical emission power of an optical detection device, wherein the optical detection device is used to emit optical signals for detection. The method for adjusting the optical emission power of the optical detection device to emit optical signals includes the following steps:

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

[0009] Determine the appropriate optical emission power value based on the obtained ambient light information; and

[0010] Adjust the optical emission power of the optical detection device according to the appropriate optical emission power value.

[0011] In an embodiment of the present invention, the optical detection device is pre-set with an adjustment lookup table, which includes the correspondence between ambient light information and the appropriate optical emission power value. The step of determining the appropriate optical emission power value based on the obtained ambient light information includes the following sub-steps:

[0012] Ambient light information is obtained through a light sensor; and

[0013] Based on the obtained ambient light information, the appropriate light emission power value is read from the adjustment lookup 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 optical signals and outputs corresponding sensing signals;

[0016] The optical detection device counts and statistically analyzes the sensing signals generated in the bin at different times of the receiving cycle to form a statistical histogram.

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

[0018] In an embodiment of the present invention, the step of determining the appropriate optical emission power value based on the obtained ambient light information includes the following sub-steps:

[0019] The relationship between the optical emission power of the optical detection device and the ambient light information is preset to a certain formula; and

[0020] The appropriate light emission power is derived based on the aforementioned preset formula and the obtained ambient light information.

[0021] In an embodiment of the present invention, the photon count of ambient light received forms the noise background in the statistical histogram. A portion of the light signal emitted by the optical detection device is reflected back by objects in space to form a sensing light signal. The photon count of the sensing light signal received is superimposed on the noise background to form a signal peak where the sensing signal count is higher than the sensing signal count of adjacent time bins. The light signal emitted with light emission power P is within a preset time window t. w The average value of the sensor signal count Ns of the sensor light signal generated inside satisfies the relationship (1): Where 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 entrance pupil radius of the lens, d represents the distance to the object, and θ l For lens transmittance, θ fLet ε represent the transmittance of the filter, FF represent the photon-triggered avalanche probability of the photosensitive pixel, FF represent the fill factor, and N represent the number of times the light signal is emitted within a detection frame. The light emission power P of the emitted light signal is adjusted according to the relationship (1) so that Ns in the formed statistical histogram satisfies the relationship (2): Where α is the confidence factor, representing the confidence level that the signal peak is above the noise background, and σ s+n It is the preset time window t w The standard deviation σ of the number of photons generated by the photons of ambient light and the photons of the sensed light signal n It is the preset time window t w The standard deviation of the photon-generated sensing signal count of the ambient light is Nn, which is the average value of the photon-generated sensing signal count of the ambient light. Nn is obtained as ambient light information through the statistical histogram. The range of the light emission power value P of the adapted light signal is determined by relation (1) and relation (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 that matches the ambient light information and confidence factor α in the current scenario can be obtained according to the adjusted relation (1), relation (2) and statistical histogram.

[0023] In embodiments of the present invention, the following steps may also be included:

[0024] The total numerical threshold range of the optical detection device is preset;

[0025] At least two sets of optical signals are emitted with different optical emission powers;

[0026] Different statistical histograms are generated for different optical signal transmission powers;

[0027] Obtain the actual total value of the sensed signals for all time bins in the statistical histogram;

[0028] Compare the actual total values ​​of the sensed signals in the statistical histograms obtained at different optical emission powers with a preset total value threshold range; and

[0029] Based on the comparison results above, select the light emission power value that matches the current ambient light information.

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

[0031] In an embodiment of the present invention, the step of comparing the actual total value of the sensed signal in the statistical histograms obtained under different light emission powers with a preset total value threshold range specifically involves comparing the first actual total value measured using the first set of light signals and the second actual total value measured using the second set of light signals with the preset total value threshold range.

[0032] In an embodiment of the present invention, the step of selecting an optical emission power value that is compatible with the current ambient light information based on the above comparison results specifically involves selecting a first optical emission power or a second optical emission power corresponding to a first actual total value or a second actual total value that is within a preset total value threshold range as the compatible optical emission power.

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

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

[0035] The optical emission power adjustment method of the optical detection device provided in this 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, extending the life of the light source, and improving the stability of the entire system.

[0036] Additional aspects and advantages of embodiments of this application will be set forth in the description which follows, and in part will be obvious from the description or may be learned by practice of embodiments of this application. Attached Figure Description

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

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

[0039] Figure 3 This is a schematic diagram showing the relationship between different signals of the optical detection device provided in the embodiments of this application;

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

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

[0042] Figure 6 This is a functional module diagram of an optical detection device provided in another embodiment of this application;

[0043] Figure 7 This is a schematic diagram of the structure of an optical detection device provided in an embodiment of this application applied to an electronic device;

[0044] Figure 8 This is a schematic diagram of the structure of an optical detection device provided in another embodiment of this application applied to an electronic device;

[0045] Figure 9 This is a statistical histogram of the sensing signal provided by the optical detection device in the embodiments of this application;

[0046] Figure 10 yes Figure 5 A schematic diagram illustrating the relationship between mid-signal peak fluctuations and noise background fluctuations;

[0047] Figure 11 This is a functional module diagram of an optical detection device provided in another embodiment of this application;

[0048] Figure 12 This is a schematic diagram of signal peaks satisfying a Gaussian distribution in the statistical histogram of the optical detection device provided in the embodiments of this application;

[0049] Figure 13 This is a schematic diagram of the signal peaks exhibiting the avalanche accumulation effect in the statistical histogram of the optical detection device provided in the embodiments of this application;

[0050] Figure 14 This is a schematic diagram of the functional modules of an optical detection device provided in another embodiment of this application.

[0051] Figure 15 This is a flowchart of the steps of a method for adjusting the light emission power of an optical detection device provided in an embodiment of this application.

[0052] Figure 16 yes Figure 15 A step-by-step flowchart of one embodiment of step S102.

[0053] Figure 17 yes Figure 15 A step-by-step flowchart of one embodiment of step S101.

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

[0055] Figure 19 This 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 this application. Specific Implementation

[0056] In the detailed description of the embodiments of this application, it should be understood that when a substrate, sheet, layer, or pattern is referred to as being "on" or "under" another substrate, sheet, layer, or pattern, it can be "directly" or "indirectly" on the other substrate, sheet, layer, or pattern, or one or more intermediate layers may also be present. For clarity, the thickness and size of each layer in the accompanying drawings may be exaggerated, omitted, or schematically represented. Furthermore, the sizes of the elements in the drawings do not perfectly reflect their actual sizes.

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0058] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or reference letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

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

[0060] Furthermore, the described features and structures can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application may be practiced without one or more of the specific details, or by employing other structures, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring this application.

[0061] This application provides a method for adjusting the optical emission power of an optical detection device, the optical detection device being used to emit optical signals for detection. The optical emission power adjustment method is used to adjust the optical emission power of the optical signal emitted by the optical detection device, and includes the following steps:

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

[0063] Determine the appropriate optical emission power value based on the obtained ambient light information; and

[0064] Adjust the optical emission power of the optical detection device according to the appropriate optical emission power value.

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

[0066] Optionally, in some embodiments, the sensing signal can be an electrical signal. Alternatively, the sensing signal can also 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 sensing 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 back by an object, such as photons in ambient light or optical signals emitted by other light sources in the scene besides the optical detection device.

[0068] Embodiments of this application also provide an electronic device, including the aforementioned optical detection device. The electronic device performs corresponding functions based on sensing information obtained by the optical detection device. The sensing information may be one or more of the following: proximity information, depth information, distance information, and other relevant information about objects in space. This relevant information can be used, for example, to determine if an object is approaching, in fields such as 3D modeling, facial recognition, autonomous driving, machine vision, monitoring, drone control, augmented reality (AR) / virtual reality (VR), and simultaneous localization and mapping (SLAM), and this application does not limit its application to these areas. The optical detection device may be, for example, a lidar, which can be used to obtain depth or distance information of objects in a scene to assist in the autonomous driving control of a vehicle.

[0069] Hereinafter, embodiments of the optical inspection device applied to electronic devices will be described in detail with reference to the accompanying drawings.

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

[0071] Figure 2 This is a schematic diagram of the functional modules of the optical detection device 10 provided in the embodiments of this application.

[0072] Reference Figure 1 and Figure 2 The electronic device 1 includes an optical detection device 10, used to measure an object 2 in space using the time-of-flight measurement principle to obtain relevant information about the object 2, such as, but not limited to, one or more of the following: proximity information, depth information, and distance information. The electronic device 1 may also include an application module 20, which can perform related functions based on the obtained sensing information of the object 2, such as, but not limited to: determining whether an object 2 is present within a preset range in front of the electronic device 1 based on its proximity information; controlling the electronic device 1 to avoid obstacles based on the distance information of the object 2; or performing 3D modeling, facial recognition, and 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 sensing light signal reflected by an object 2 in space. The time difference between emitting the light signal and receiving the sensing light signal is called the time of flight t. The depth information of the object 2 is obtained by calculating the distance traveled by the light signal during the aforementioned time of flight. 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 embodiments described below, the optical detection device 10 is mainly used as a DTOF measurement device for illustration.

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

[0077] The emitting module 12 includes a light-emitting unit 120 and a modulation element 124. The light-emitting unit 120 is used to emit light signals. The modulation element 124 is used to modulate the light signals emitted by the light-emitting unit 120 to form light signals that can be used for sensing and to project them into the space. Optionally, the light signals emitted by the emitting module 12 may be, for example, but not limited to, speckle patterns or floodlight beams.

[0078] Optionally, in some embodiments, the modulation element 124 is, for example, a diffuser or a homogenizer, 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), used to replicate the light signal emitted by the light-emitting unit 120 and expand its arrangement within a preset field of view to form a speckle pattern. The speckle pattern can be regularly arranged, irregularly arranged, or randomly arranged, etc.

[0080] By replicating the light signal emitted by the light-emitting unit 120 through the DOE, the light signal emitted to the object 2 is composed of multiple replicated light signals, which helps to expand the field of view of the optical detection device 10 and improve the sensing effect.

[0081] Optionally, in some embodiments, the modulation element 124 can be other suitable beam modulation element types, such as, but not limited to, microlens arrays, etc., which are not limited in this application.

[0082] Optionally, in some embodiments, the transmitting module 12 may also include other suitable optical elements, such as a lens (not shown) disposed in the path of the light signal emitted from the light-emitting unit 120. The lens may be disposed between the light-emitting unit 120 and the modulation element 124 to collimate or converge the light signal emitted by the light-emitting unit 120 before transmitting it to the modulation element 124. The lens may be a combination of multiple single lenses.

[0083] It should be understood that the embodiments of this application do not specifically limit the wavelength range of the light signal emitted by the light-emitting unit 120. Optionally, the light 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. These multiple light sources may, for example, be a regularly arranged or irregularly arranged array of light sources. If the light-emitting unit 120 is a vertical-cavity surface-emitting laser (VCSEL), 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 also be a light source in the form of an edge-emitting laser (EEL), a light-emitting diode (LED), or a laser diode (LD). The edge-emitting laser may be a Fabry-Perot (FP) laser, a distributed feedback (DFB) laser, or an electro-absorption modulated (EML) laser; this application does not limit the specific type of laser used.

[0086] Optionally, in some embodiments, the receiving module 14 may include an image sensor 140. The image sensor 140 may include, for example, a single photosensitive pixel 142 or a pixel array composed of multiple photosensitive pixels 142, the pixel array being 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, one or more of a single-photon avalanche diode (SPAD), an avalanche photodiode (APD), a photodiode, and 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 the following devices connected to the image sensor 140: a signal amplifier, a time-to-digital converter (TDC), and an analog-to-digital converter (ADC). Optionally, the readout circuit may also be partially or wholly integrated into the image sensor 140.

[0089] Optionally, the receiving module 14 may further include a lens unit 144, which can be used to receive the sensing light signal reflected from the object 2, and collimate or converge the sensing light signal before transmitting 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 the distance between them can range from, for example, 2 mm to 20 mm. It is understood that in some embodiments, both the transmitting module 12 and the receiving module 14 transmit optical signals, and the distance between them refers to the distance between the optical axes of their respective optical systems. The transmitting module 12 includes a light-emitting surface for emitting optical signals, and the receiving module 14 includes a light-incident surface for receiving optical 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, to control the frequency of the emitted light signal, the position of the light source lit at different times, and the luminous power of the light source. Optionally, in some embodiments, the control module 18 includes an emission control unit 180, which is used to control the light-emitting unit 120 to emit a light signal into space at a preset frequency, such as 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 light signals according to a emission control signal with a preset frequency. It is understood that the emission control signal can be a drive signal applied to the driving 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 and low-level segments. The light-emitting unit 120 is controlled to continuously emit light into space during the high-level segment and stops emitting light during the low-level segment, thereby emitting the corresponding light signal. Thus, within the time sequence corresponding to the high-level segment, the light-emitting unit 120 continuously emits light signals into space, and at least a portion of the light signals can be reflected back from the object 2 in space.

[0093] It is understood 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. The light-emitting unit 120 continuously emits the optical signal during the light-emitting segment and stops emitting light during 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, some 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 can be used to control the receiving module 14 to synchronously activate the receiving sensor at the beginning of each transmission cycle of the optical signal to sense the returned photons. Thus, the receiving module 14 has a receiving cycle corresponding to the transmission cycle of the optical signal, the start time of the receiving cycle corresponding to the start time of the transmission cycle, and the end time of the receiving cycle corresponding to the end time of the transmission cycle. Optionally, in some embodiments, the start time of the receiving cycle is synchronized with the start time of the transmission cycle, and the end time of the receiving cycle is synchronized with the end time of the transmission cycle.

[0096] Specifically, in some embodiments, the receiving control unit 182 is used to control the photosensitive pixel 142 to synchronously begin sensing photons at the beginning of each transmission cycle of the optical signal. The photosensitive pixel 142 is, for example, a SPAD. A SPAD can only sense a single photon in one receiving cycle. Once a SPAD is triggered by a single photon in one receiving cycle, an avalanche effect occurs, generating a corresponding sensing signal. After the avalanche, the SPAD needs to be quenched and reset to restore the bias voltage above the breakdown voltage so that it can sense photons again in the next receiving cycle. Based on the above characteristics, a SPAD can sense one photon of the returned sensing optical signal and generate a corresponding sensing signal in one receiving cycle. It is understood that a SPAD may also fail to sense a photon in one receiving cycle and thus not generate a corresponding sensing signal. However, regardless of whether a photon is sensed, the SPAD will be reset before the end of one receiving cycle so that it can resume sensing the received photons at the beginning of the next receiving cycle.

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

[0098] Optionally, the photosensor 16 can be used to sense ambient light information of the scene where the optical detection device 10 is located. This ambient light information includes, but is not limited to, the wavelength, intensity, and color temperature of the ambient light. One or more different photosensitive channels are provided along the path through which the photosensor receives ambient light. The photosensor 16 includes filters and photoelectric conversion elements corresponding to different photosensitive channels to sense ambient light information in different wavelength ranges. Optionally, the photosensitive channel may include one or more combinations 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 visible light, the filter of the red light channel transmits red light, the filter of the green light channel transmits green light, the filter of the blue light channel transmits blue light, and the filter of the wide-spectrum channel transmits both visible and infrared light. The light sensor 16 can provide spectral information for each of the above channels (CRGBW) and thereby derive the corresponding ambient light information.

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

[0100] Optionally, the control module 18 may further include a power adjustment unit 184, which can 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 can 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 light 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 emitting light on the light-emitting unit 120, for example, activating fewer light sources to emit light at lower light emission power and activating more light sources to emit light at higher light emission power.

[0102] Optionally, in some embodiments, the optical detection device 10 is pre-set with an adjustment lookup table, which includes the correspondence between ambient light information and light emission power values. This table can be obtained by calibrating the optical detection device 10 to adapt to different ambient light scenarios with appropriate light emission power. The adjustment lookup table can be pre-set according to calibration and stored in the storage medium 30 of the optical detection device 10 or electronic device 1 for retrieval.

[0103] Optionally, in some embodiments, the ambient light information can be an ambient light intensity value. The adjustment lookup table includes the correspondence between ambient light intensity values ​​and suitable light emission power values, which can be used to determine the light emission power value of the optical detection device 10 that is compatible with the sensed ambient light intensity value. It is understood that in other embodiments, the adjustment lookup table may also include the correspondence between light emission power values ​​and other ambient light information, such as color temperature and wavelength. The power adjustment unit 184 can determine the light emission power value compatible with the scene based on the ambient light information obtained by the light 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 sensor 16, then read the adjustment lookup table according to the ambient light intensity value to determine the corresponding suitable 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 light signal emission power can be appropriately reduced in the scene with weak ambient light, thereby reducing the power consumption of the optical detection device 10, improving the life of the light source, and improving the stability of the entire system.

[0105] In some embodiments, such as Figure 4 As shown, the light sensor 16 can be integrated onto the transmitting module 12. For example, the transmitting module 12 may include a light-emitting unit 120, a light sensor 16, and a control module 18. The light-emitting unit 120 is used to emit light signals into space, and at least a portion of the emitted light signals is reflected back from the object 2 in space to form a sensing light signal. The light sensor 16 is used to detect ambient light information in space. The control module 18 adjusts the emission power of the light-emitting unit 120 to emit light signals into space based on the ambient light information detected by the light sensor 16. Optionally, the light sensor 16 and the light source on the light-emitting unit 120 can be packaged together in a single package. Alternatively, the light sensor 16 and the light source on the light-emitting unit 120 can be packaged separately to form different components.

[0106] In some embodiments, such as Figure 5As shown, the light sensor 16 can be integrated onto the receiving module 14. For example, the receiving module 14 may include an image sensor 140 and a light sensor 16. Optionally, the light sensor 16 and the photosensitive pixels 142 on the image sensor 140 can be formed on the same semiconductor substrate. Alternatively, the light sensor 16 and the photosensitive sensor 140 can be packaged together in a single package. Alternatively, the light sensor 16 and the image sensor 140 can be packaged separately. It is understood that in these embodiments, the control module 18 can be integrated into the transmitting module 12, or it can be disposed in other parts of the optical detection device 10 instead of being integrated into the transmitting module 12.

[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 center of the front of the mobile phone; or, the light sensor 16 may be disposed on the 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 disposed below the display screen 40. The light sensor 16 can sense ambient light information outside the electronic device 1 through the display screen 40. Further, optionally, the electronic device 1 may also include a fingerprint sensor 50, which is also disposed 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 fingerprints of fingers that come into contact with the fingerprint sensing area. The light sensor 16 is disposed side-by-side with the fingerprint sensor 50 below the display screen 40, and the orthographic projection of the light sensor 16 onto the outer surface of the electronic device 1 is located within the fingerprint sensing area. The optical detection device 10 can be disposed side-by-side with the display screen 40 or below the display screen 40. It is understood that the electronic device 1 may also include a cover glass 60, which can be disposed 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 disposed at the top center of the front of the mobile phone; or, the optical detection device 10 can also be disposed 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, sensing 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, the outer cover plate 70 is the panel of the smart door lock, and 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 time-of-flight 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 through a through hole in the outer cover plate 70, thereby allowing the time-of-flight measurement of the external object 2 to be performed directly without passing through the outer cover plate 70.

[0111] It is understood that if the light sensor 16 can also be set in other locations on the electronic device 1 besides the optical detection device 10, the optical detection device 10 can optionally be provided with a dedicated interface to connect with the light 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 sensor 16 through the micro-controller (MCU) on the electronic device 1.

[0112] Optionally, in some embodiments, the light signal emitted by the light-emitting unit 120 is infrared or near-infrared light, with a wavelength range of 700nm to 2000nm, such as 850nm, 905nm, 940nm, 1064nm, 1550nm, etc. The light sensor 16 can be used to sense the intensity of infrared 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 light signal emission power of the light-emitting unit 120 according to the sensed intensity of infrared or near-infrared light in the 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 or distance information of an 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 to this; 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, as... Figure 8As shown, the processing module 15 can also be located in other positions in the electronic device 1 besides the optical detection device 10. For example, the processing module 15 can be the main control module of the electronic device 1, and this application does not limit this. Optionally, such as Figure 1 As shown, the light sensor 16 can be integrated into the optical detection device 10. Alternatively, as... Figure 8 As shown, the light sensor 16 can also be located in other positions in the electronic device 1 besides the optical detection device 10, and this application does not limit this.

[0115] Please refer to the following: Figure 2 , 3 In some embodiments, the processing module 15 may include a timing unit 150, a counting unit 152, and a statistics unit 154. The timing unit 150 can divide the reception period into multiple time blocks starting from the start time, each time block corresponding to a preset time interval Δt. Optionally, the time interval Δt corresponding to each time block is equal. Optionally, the time interval Δt can be the smallest time interval Δt that the TDC can resolve. It is understood that the time difference between each time block and the start time of the reception period can be used as the timestamp of that time block. 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 reception period and the start time of that reception period, as the timestamp of the sensing signal.

[0116] Optionally, in some embodiments, the counting unit 152 can be used to accumulate counts within time bins with corresponding timestamps based on the timestamp of the sensing signal, that is, to increment the number of sensing signals with the same timestamp already counted in that time bin by one. It is understood that, for embodiments using SPADs as photosensitive pixels 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, thus accumulating the count in one of the many time bins, or it may not receive any photons and therefore not generate a sensing signal, thus not accumulating the count in any time bin.

[0117] It is understood that the light signal received by the receiving module 14 may include the sensing light signal emitted from the transmitting module 12 and reflected back by the object 2 in the space, or it may include other light signals that are not emitted by the transmitting module 12 or reflected back by the object 2, such as 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 statistics unit 154 can be used to count the cumulative number of sensed signals in each corresponding time bin within multiple receiving periods to generate a corresponding statistical histogram. The horizontal axis of the statistical histogram represents the timestamp of each corresponding time bin, and the vertical axis represents the cumulative count of sensed signals in each corresponding time bin. Optionally, the statistics unit 154 can be a histogram circuit.

[0119] During the sensing process, a large number of ambient light photons are also received by the receiving module 14, generating corresponding sensing signal counts. The probability of these ambient light photons being sensed and leaving a count in each time bin tends to be the same, constituting the noise level of the sensing data. In scenarios with high ambient light intensity, the average level of the measured noise level is correspondingly higher; in scenarios with low ambient light intensity, the average level of the measured noise level is correspondingly lower. Based on this, the sensing signal counts generated by the receiving module 14 when photons of the sensing light signal emitted from the transmitting module 12 and reflected back by the object 2 are sensed are superimposed on the noise level, making the sensing signal count in the time bin corresponding to the sensed sensing light signal significantly higher than the sensing signal counts in other time bins, thus forming a corresponding signal peak. It is understood that the count height of the signal peak is 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; the width of the signal peak is affected by factors such as the width of the emitted light signal, the time jitter of SPAD and TDC. Therefore, the timestamp t0 of the time bin corresponding to the signal peak is the time of flight of the sensed light signal, which can be used to calculate the depth or distance information of object 2. It is understood that the processing module 15 may also include a sense information calculation unit 156. The sense information calculation unit 156 can be used to derive the relevant sensed information of object 2 in space based on the timestamp t0 of the signal peak determined by the statistical histogram.

[0120] Understandably, based on the aforementioned sensing principle, the timestamp t0 of the sensed light signal reflected from object 2 is calculated from the start of the receiving cycle, which is also the start of the light signal emission cycle. Therefore, it is impossible to determine exactly which moment in the emission cycle the sensed light signal was emitted from, leading to a certain degree of detection error. This error can be reduced by shortening the duration of the emission segment within the emission cycle. Optionally, in some embodiments, the duration of the emission segment in the light signal emission cycle can range from 500 picoseconds (ps) to 500 nanoseconds (ns), for example: 500 ps, ​​600 ps, ​​800 ps, ​​1 ns, 20 ns, 50 ns, 100 ns, 200 ns, etc.

[0121] Optionally, in some embodiments, the light-emitting unit 120 emits a light signal with light emission power P within a preset time window t. w The average value of the sensor signal count Ns generated within the sensor light signal can be calculated using the following formula (1):

[0122]

[0123] Where A is a fixed coefficient, P is the light emission power of the light 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 entrance pupil radius of the lens, d represents the distance to object 2, and θ l For lens transmittance, θ f ε represents the transmittance of the filter, FF represents the probability of SPAD photon-triggered avalanche, FF represents the fill factor, and N represents the number of light signal emissions within a detection frame. To make the count statistically meaningful, the number of light signal emissions within a detection frame ranges from tens of thousands to millions.

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

[0125] The distance d of the object 2 can be preset. Optionally, the object distance d can be the maximum value of the effective ranging range calibrated by the optical detection device 10 at the factory. Alternatively, the object distance d can be an initial measurement 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 of the actual distance of the object.

[0126] Photons of ambient light and photons of the sensed light signal reflected from object 2 have a certain probability of being received by the photosensitive pixel 142 of the receiving module 14. The photosensitive pixel 142 can be of SPAD type, thus leaving a sensed signal count in the corresponding time bin. Both the photons of ambient light and the photons of the sensed light signal, as discrete random probability events, follow a Poisson distribution. Assuming that in each time bin, the expected value of the number of ambient light photons sensed is Nn, and the expected value of the number of sensed light signal photons sensed is Ns, then Nn is the average sensed signal count against the noise background, and Ns is the average sensed signal count superimposed on the noise background when the photons of the sensed light signal are sensed. Figure 10 As shown, the actual values ​​of the noise background sensing signal count Nn` and the actual values ​​of the sensing light signal count Ns` within a single time bin follow a Poisson distribution, exhibiting numerical fluctuations around the average values ​​of the noise background sensing signal count Nn and the average values ​​of the sensing light signal count Ns, respectively. Assume the standard deviations of these fluctuations are σn and σs, respectively. To accurately identify the signal peak, the actual value of the sensing signal count Nn`+Ns` in the time bin containing the signal peak needs to be higher than the actual value of the sensing signal count Nn` in the time bin containing the noise background to be effectively identified. Therefore, the fluctuation of the actual value of the signal peak count needs to be minimized to (Nn+Ns)-(σs). s+n The fluctuation high value (Nn+σ) is more likely to be higher than the actual count value under noise background. n According to the above conditions, the optical emission power P of the transmitted optical signal of the transmitting module 12 can be adjusted according to the relation (1) so that Ns in the formed statistical histogram satisfies the relation (2):

[0127]

[0128] Where α is the confidence factor, representing the confidence level that the signal peak is above the noise background, and σ s+n It is the preset time window t w The standard deviation of the count rate of the sensing signal generated by the photons of ambient light and the photons of the sensing light signal, σ n It is the preset time window t w The standard deviation of the count rate of the sensor signal generated by photons from indoor ambient light. Nn is the preset time window t. w The average count of the sensing signal generated by the photons of the sensed ambient light is Nn, which, as ambient light information, can be obtained from the statistical histogram. Ns is the preset time window t. w The average count of the sensing signal generated by the photons of the sensed light signal sensed within the window. Optionally, the preset time window t wThe time interval can be represented by one time bin or multiple unspecified time bins, and the corresponding average value Nn of the sensed signal count on the noise background can be obtained by applying a preset time window t. w The actual value Nn` of the noise background sensing signal count of each of the multiple time-division boxes is averaged to obtain the result.

[0129] The higher the light emission power of the light signal, the higher the average value of the sensed signal count Ns. The higher the intensity of the ambient light, the higher the average value of the sensed signal count Nn against the noise background. As can be seen from equation (2), the light emission power of the adapted light signal is directly related to the intensity of the ambient light. When the intensity of the ambient light is greater, the average value of the sensed signal count Nn against the noise background is also greater. If the light emission power of the light signal remains unchanged, the confidence factor α that satisfies equation (2) will become smaller, thereby affecting the accuracy of peak finding during the detection process. Therefore, when the intensity of the ambient light is greater, the optical detection device 10 also needs to increase the light emission power of the light 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 relatively large to meet the harsh scenarios with high ambient light intensity. However, this will waste the light emission power in weak ambient light scenarios, and will also easily reduce the lifespan of the light source, increase the heat generation of the entire system, and increase the instability of the system.

[0130] Substituting the above relation (1) into relation (2), and then using the statistical histogram obtained by the statistical unit 154 to determine the preset time window t. w The average value Nn of the sensing signal count against the background noise can be used to derive the range of light emission power values ​​that are compatible with the ambient light information of the current scene using equations (1) and (2). Therefore, the power adjustment unit 184 of the control module 18 can adjust the light emission power of the light-emitting unit 120 based on the adapted light emission power value P obtained above.

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

[0132] Optionally, in some embodiments, the accuracy of the optical detection device 10 can be adjusted to suit scenarios with different detection accuracy requirements. Optionally, the accuracy of the optical detection device 10 can be reflected in the magnitude of the confidence factor α in equation (2). The larger the confidence factor α, the higher the reliability of the measurement results of the optical detection device 10; the smaller the confidence factor α, the lower the reliability of the measurement results of the optical detection device 10. Thus, under the premise that other conditions remain unchanged, a decrease in the confidence factor α will correspondingly reduce the optical emission power of the optical signal, and an increase in the confidence factor α will correspondingly increase the optical emission power of the optical signal.

[0133] Optionally, in some embodiments, if the confidence factor α is adjusted, the power calculation unit 186 can derive a range of light emission power values ​​that are compatible with the ambient light information and confidence factor α of the current scene based on the adjusted relational formulas (1) and (2) and the statistical histogram. The power adjustment unit 184 then adjusts the light emission power of the light-emitting unit 120 according to the recalculated range of light emission power values. Optionally, in other embodiments, an adjustment lookup table including the relationship between the confidence factor α, ambient light information, and light emission power values ​​can be preset by calibration. If the confidence factor α is adjusted, the power adjustment unit 184 can readjust 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 ambient light information in the current scene through the statistical histogram, then determine the corresponding adaptive 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 light signal can be appropriately reduced in the scene with weak ambient light, thereby reducing the power consumption of the optical detection device 10, improving the life of the light source, and improving the stability of the entire system.

[0135] The photons of the sensed light signal reflected back from object 2, as discrete random probability events, cumulatively follow a Gaussian distribution over time, such as... Figure 12 As shown, the count values ​​in the time bins of the statistical histogram that follows a Gaussian distribution will gradually increase towards the signal peak. Since a SPAD can only sense a single photon in one reception cycle, when the optical detection device 10 is too close to the object 2 or the light emission power is relatively too strong, the longer-flight-time returning photons will be overwhelmed by the shorter-flight-time returning photons, resulting in a pile-up effect. Figure 13As shown, this is reflected in the statistical histogram by a signal peak with a total value significantly higher than normal, but the count values ​​in the time bins following the signal peak decrease significantly, thus not conforming to a Gaussian distribution. The avalanche accumulation effect distorts the actual measured statistical histogram, and the measured time of flight is also underestimated. Figure 14 As shown, in some embodiments, the optical detection device 10 may have a preset total value threshold range, and the control module 18 may further include a comparison unit 188. The comparison unit 188 can compare the actual total value 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 value of the preset total value threshold range, the light emission power is reduced by the power adjustment unit 184; if the actual total value is lower than the minimum 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 indicates that the current light emission power is appropriate and no adjustment is needed. 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 based on the judgment result of the comparison unit 188, and the light 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 statistical analysis, i.e., the number of light signals emitted by the corresponding light-emitting unit 120. It is understood that, for statistical significance, the number of receiving cycles in a single effective detection process can range from tens of thousands to millions. A single effective detection process can also be defined as a detection frame, in which 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 understood 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 can also control the light-emitting unit 120 to emit at least two sets of light signals at different light emission powers. For example, multiple light signals can be continuously emitted at a first light emission power as the first set of light signals, and multiple light signals can be continuously emitted at a second light emission power as the second set of light signals. The first light emission power is greater than the second light emission power. It is understood that the at least two sets of light signals can be emitted within one detection frame or in different detection frames. The comparison unit 188 of the control module 18 compares the first actual total value measured using the first set of light signals and the second actual total value measured using the second set of light signals with a preset total value threshold range, and selects a light emission power adapted to the current ambient light information based on the comparison results.

[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 emission power or the second optical emission 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 emission power.

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

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

[0141] Understandably, if both the first and second actual total values ​​are outside the preset total value threshold range, the control module 18 can control the light-emitting unit 120 to continuously emit multiple light signals at a third light emission power as a third set of light signals, and at a fourth light emission power as a fourth set of light signals. The third light emission power can be less than the first light emission power but greater than the fourth light emission power, and the fourth light emission power can be greater than the second light emission power. The comparison unit 188 of the control module 18 compares the third actual total value measured using the third set of light signals and the fourth actual total value measured using the fourth set of light signals with the preset total value threshold range. Based on the comparison results, it selects the appropriate light emission power for the current ambient light information. The selection method for the first and second actual total values ​​can be referenced to select the third and fourth actual total values, and so on, until at least one actual total value that meets the preset total value threshold range is found. The corresponding light emission power is then used as the basis for adjusting the light emission power of the light-emitting unit 120.

[0142] It is understood that the selection of the third and fourth optical emission powers can be determined based on the difference between the first and second actual total values ​​and the end value of the total value threshold range. If the difference is greater than the larger end value of the total value threshold range, the corresponding optical emissivity power is reduced; if the difference is smaller than the smaller end value of the total value threshold range, the corresponding optical emission power is increased. 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 processing module 15 may be firmware embedded in the storage medium 30 or computer software code stored in the storage medium 30. The control module 18 and processing module 15 are executed by one or more corresponding processors (not shown) to control related components to achieve corresponding functions. The processors are, for example, but not limited to, application processors (AP), central processing units (CPU), microcontrollers (MCUs), 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 disks, etc.

[0144] Optionally, in some embodiments, the processor and / or storage medium 30 may be disposed within 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 other embodiments, the processor and / or storage medium 30 may also be disposed in other locations of the electronic device 1, such as on the main circuit board of a mobile phone.

[0145] Optionally, in some embodiments, some or all functional units of the control module 18 and / or processing module 15 may also be implemented in hardware, for example, by any one or a combination of the following techniques: discrete logic circuits having logic gates for implementing logic functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc. It is understood that the hardware used to implement the functions of the control module 18 and / or processing module 15 may be located within the optical detection device 10, for example, integrated on the same circuit board as the photoelectric sensor 140 or the light source. The hardware used to implement the functions of the control module 18 and / or processing module 15 may also be located in other locations on the electronic device 1, for example, on the motherboard of a mobile phone.

[0146] Compared with the prior art, the optical detection device 10 of this application can adjust the light emission power of the emitted light signal to match the current scene, so as to reduce power consumption as much as possible, extend the 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 while ensuring the detection effect.

[0147] like Figure 15 As shown in the illustration, this application also provides a method for adjusting the light emission power of an optical detection device 10. The optical detection device 10 is used to emit light signals into space and obtain relevant sensing information of the object 2, such as depth information, distance information, or proximity information, by sensing the sensing light signals reflected back from an object 2 in space. The light emission power adjustment method can be used to adjust the light emission power of the light signals emitted by the optical detection device 10, and the light emission power adjustment method includes the following steps:

[0148] Step S101: Obtain 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, and color temperature of the ambient light. It is understood that the portion of the ambient light with the same wavelength as the emitted light signal will interfere with the emitted light signal. Optionally, in some embodiments, the light signal is infrared or near-infrared light; correspondingly, the obtained ambient light information is related to the infrared or near-infrared portion of the ambient light.

[0149] Step S102: Determine the appropriate light emission power value based on the obtained ambient light information.

[0150] Step S103: Adjust the optical emission power according to the adapted optical emission power value.

[0151] Optionally, in some embodiments, ambient light information can be obtained in step S101 using a light sensor 16. The light sensor may include one or more different photosensitive channels, each including a filter that transmits light within a corresponding wavelength range and a corresponding photoelectric conversion element. Optionally, the photosensitive channel may include one or more of a visible full-spectrum channel (Clear), a red channel (Red), a green channel (Green), a blue channel (Blue), and a wide-spectrum channel (Wide). The filter of the visible full-spectrum channel transmits visible light, the filter of the red channel transmits red light, the filter of the green channel transmits green light, the filter of the blue channel transmits blue light, and the filter of the wide-spectrum channel transmits both visible and infrared light. The light sensor 16 can provide spectral information for each of the above channels (CRGBW) and thereby derive corresponding ambient light information.

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

[0153] Correspondingly, such as Figure 16 As shown, in some embodiments, step S102 includes the following sub-steps:

[0154] Step S1021: Preset an adjustment lookup table for optical emission power. Specifically, an adjustment lookup table is established by calibrating the optical emission power adapted to different ambient light scenarios of the optical detection device 10. The adjustment lookup table includes the correspondence between ambient light information and the adapted optical emission power value.

[0155] Step S1022: Obtain relevant information about ambient light through a light sensor. Optionally, the relevant information about ambient light may be the light intensity of the ambient light.

[0156] Step S1023: Read the appropriate light emission power value from the adjustment lookup table based on the obtained ambient light information.

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

[0158] In step S1011, a sensing signal is generated. The optical detection device 10 receives photons from ambient light and photons from the sensing light signal and outputs a corresponding sensing signal. Optionally, the sensing signal can be an electrical signal. Alternatively, the sensing signal can be other signals, such as a magnetic signal, depending on the photon conversion principle of the receiving module.

[0159] Step S1012: A statistical histogram is formed. The optical detection device 10 counts and statistically analyzes the sensing signals generated in different time slots of the receiving period to form a statistical histogram. The statistical histogram can be used to obtain the time of flight corresponding to the sensing light signal to obtain relevant sensing information of the object 2. A large number of ambient light photons are also received by the receiving module 14, generating corresponding sensing signal counts. The probability of these ambient light photons being sensed and leaving a count in each time slot tends to be the same, forming a noise background in the sensing data. The counts generated by the photons of the sensing light signal are superimposed on the noise background to form a signal peak where the sensing signal count is higher than that of the adjacent time slot. In scenarios with high ambient light intensity, the average level of the measured noise background is correspondingly higher; in scenarios with low ambient light intensity, the average level of the measured noise background 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 from the noise background of each time bin in the statistical histogram, such as the intensity of the ambient light. Both the photons of the ambient light and the photons of the sensed light signal are discrete random probability events that follow a Poisson distribution. Assuming that the expected value of the number of sensed photons of the ambient light in each time bin is Nn, and the expected value of the number of sensed photons of the sensed light signal is Ns, then Nn is the average count of the noise background, and Ns is the average count of the effective sensed photons superimposed on the noise background. Therefore, Nn obtained through the statistical histogram can reflect the ambient light information in the current scene of the optical detection device 10.

[0161] Correspondingly, such as Figure 18 As shown, in some embodiments, step S102 may further include the following sub-steps:

[0162] Step S1024: Preset the 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 light signal is within a preset time window t. w The average count Ns of photons generated internally and effectively sensed by the receiving module satisfies the relationship (1): Where 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 by the receiving module for sensing, D is the entrance pupil radius of the lens, d represents the distance to the object, and θ l For lens transmittance, θ f Let ε represent the transmittance of the filter, FF represent the photon-triggered avalanche probability of the photosensitive pixel, FF represent the fill factor, and N represent the number of light signal emissions within a detection frame. The light emission power P of the emitted light signal is adjusted so that Ns in the resulting statistical histogram satisfies equation (2): Where α is the confidence factor, representing the confidence level that the signal peak is above the noise background, and σ s+n It is the preset time window t w The standard deviation, σ, of the count of photons from ambient light and the photons from the sensed light signal. n It is the preset time window t w The standard deviation of the count of the sensing signal generated by the photons of the indoor ambient light, where Nn is the preset time window t. w The average count of photons of ambient light sensed within the space, Nn, can be determined using the statistical histogram, where Ns is a preset time window t. w The average count of photons of the sensed light signal sensed within the sensor. It is understood that in other embodiments, other pre-defined relationships related to ambient light information and light emission power can be used to calculate the adaptive light emission power.

[0163] Step S1025: Obtain the light emission power value that matches the obtained ambient light information. For example, the matching light emission power can be obtained based on the above-mentioned preset relationship and the obtained ambient light information. Specifically, in some embodiments, the above-mentioned relationship (1) is substituted into relationship (2), and then the preset time window t is determined from the statistical histogram. w The average count Nn of the noise background can be used to substitute the average count Nn of the noise background into equations (1) and (2) to obtain the range of optical emission power values ​​for the suitable optical signal. Optionally, the preset time window t w It can be the sum of time intervals represented by one or more unspecified time bins, and the corresponding average count Nn of the noise background can be the time window t.w 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. The power calculation unit 186 can calculate the range of light emission power values ​​adapted to the ambient light in the current scenario based on the adjusted relation (1), relation (2), and statistical histogram. The power adjustment unit 184 then adjusts the light emission power of the light-emitting unit 120 according to the recalculated range of light emission power values. Optionally, in other embodiments, an adjustment lookup table including the relationship between the confidence factor α, ambient light information, and light emission power values ​​can be preset by calibration. If the confidence factor α is adjusted, the power adjustment unit 184 can readjust the light emission power of the light-emitting unit 120 according to the above adjustment lookup table. Thus, step S1025 can calculate the adapted light emission power value based on the adjusted confidence factor α.

[0165] Optionally, in some embodiments, such as Figure 19 As shown, it may also include the following steps:

[0166] In step S100, at least two sets of optical signals are emitted with different optical emission powers. For example, multiple optical signals are continuously emitted at a first optical emission power as the first set of optical signals, and multiple optical signals are continuously emitted at a second optical emission power as the second set of optical signals. The first optical emission power is greater than the second optical emission power.

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

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

[0169] Step S1026: Preset the total numerical threshold range of the optical detection device 10.

[0170] Step S1027: Compare the actual total values ​​of the statistical histograms obtained under different light emission powers with the preset total value threshold range.

[0171] Step S1028: Select the light emission power that matches the current ambient light information based on the comparison results above.

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

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

[0174] Optionally, in some embodiments, the first actual total value measured using the first set of optical signals and the second actual total value measured using the second set of optical signals are compared with a preset total value threshold range. If both the first actual total value and the second actual total value are within the preset total value threshold range, the optical emission power corresponding to the one of the first actual total value and the second actual total value that is closest to the median value of the total value threshold range is selected as the adapted optical emission power.

[0175] Optionally, in some embodiments, the first actual total value measured using the first set of optical signals and the second actual total value measured using the second set of optical signals are compared with a preset total value threshold range. If both the first actual total value and the second actual total value are within the preset total value threshold range, the smaller second optical emission power is selected as the adapted optical emission power.

[0176] It should be understood that various parts of the embodiments of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in storage medium 30 and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0177] It should be noted that those skilled in the art will understand that, without creative effort, all or part of the embodiments of this application, as well as all or part of the modifications, substitutions, alterations, splits, combinations, extensions, etc., of the embodiments should be considered to be covered by the inventive concept of this application and fall within the protection scope of this application.

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

[0179] The terms "length," "width," "upper," "lower," "left," "right," "front," "rear," "back," "front," "vertical," "horizontal," "top," "bottom," "inner," and "outer" that may appear in this application specification are based on the orientations or positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing the embodiments of this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Similar reference numerals and letters in the drawings denote similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this application, "multiple" or "a plurality of" means at least two or more, unless otherwise explicitly specified. In the description of this application, it should also be noted that, unless otherwise explicitly specified and limited, "setting," "installation," and "connection" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0180] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The terminology used in the claims should not be construed as limiting the invention to the specific embodiments disclosed in this specification. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of adjusting optical transmission power of an optical detection apparatus for transmitting an optical signal for detection, the method comprising: determining a first optical transmission power of the optical detection apparatus; determining a second optical transmission power of the optical detection apparatus; and adjusting the first optical transmission power to the second optical transmission power. The light emission power adjustment method is used for adjusting the light emission power of the optical detection device, which comprises the following steps: obtaining the ambient light information of the scene where the optical detection device is located; determining the 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; wherein the step of obtaining the ambient light information of the scene where the optical detection device is located comprises the following steps: the optical detection device receives the light signal and outputs the corresponding sensing signal; the optical detection device counts the sensing signals generated in different time bins of the receiving period to form a statistical histogram; obtaining the related 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 steps: presetting the relationship between the light emission power of the optical detection device and the ambient light information; and obtaining the adapted light emission power according to the above preset relationship and the obtained ambient light information; The sensing signal counts generated by the photons of the ambient light form a noise background in the statistical histogram. Part of the light signals emitted by the optical detection device is reflected back by the object in the space to form a sensing light signal. The sensing signal counts generated by the photons of the sensing light signal are superimposed on the noise background to form a signal peak with sensing signal counts higher than the sensing signal counts of adjacent time bins. The average value N of the sensing signal counts of the sensing light signal generated by the light signals emitted at a preset light emission power P within a preset time window t w The average value N of the sensing signal counts of the sensing light signal generated by the light signals emitted at a preset light emission power P within a preset time window t s The relationship (1) is satisfied: ， Wherein, A is a fixed coefficient, P is the optical signal light emission power, γ is the reflectivity of the object, h represents the Planck constant, c represents the speed of light, λ represents the light wavelength, M represents the number of photosensitive pixels 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 trigger avalanche probability of the photosensitive pixel, FF represents the fill factor, N is the emission times of the optical signal in a detection frame, and the light emission power P of the emitted optical signal is adjusted according to the relationship formula (1) so that the N s satisfies the relationship formula (2): ， wherein a is a confidence factor representing the confidence of the signal peak being above the noise floor, and s+n is the standard deviation of the sensed signal counts produced by the photons of the ambient light within the preset time window t w is the standard deviation of the sensed signal counts produced by the photons of the ambient light within the preset time window t n is the standard deviation of the sensed signal counts produced by the photons of the ambient light within the preset time window t w is the standard deviation of the sensed signal counts produced by the photons of the ambient light within the preset time window t n is the average of the sensed signal counts produced by the photons of the sensed ambient light within the preset time window t w is the average of the sensed signal counts produced by the photons of the sensed ambient light within the preset time window t n The range of the adapted light signal light emission power value P is determined by the relationship (1) and the relationship (2) as the ambient light information is obtained by the statistical histogram.

2. The optical transmit power adjustment method of claim 1, wherein, the confidence factor α is adjusted according to the application scene, 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.

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