Secure method for device configured to emit high intensity light

Abstract

Some disclosed devices include a light source system, a target detection system; and a control system configured to communicate with the light source system and the target detection system. The control system may also be configured to receive target detection data from the target detection system, estimate the presence or absence of the biological target based at least in part on the target detection data, and enable or disable the light source system based at least in part on the estimate of the presence or absence of the biological target. For example, if a biological target is detected, the control system may enable the light source system.

Description

[0001] Priority Claim

[0002] This application claims priority to U.S. Patent Application No. 18 / 057,484, filed on November 21, 2022, entitled "Safety Method for Devices Configured to Emit High Intensity Light", which is incorporated herein by reference for all purposes. Technical Field

[0003] The present invention generally relates to methods, devices, and systems for protecting people from unexpected exposure to high-intensity light, such as protecting people's eyes from lasers. Background Art

[0004] A variety of different sensing technologies and algorithms are being implemented in devices for various biometric and biomedical applications, including health and wellness monitoring. Some such devices use high-intensity light, such as lasers. Improved methods, devices, and systems are desired for protecting people from unexpected exposure to high-intensity light, such as for protecting people's eyes from lasers. Summary of the Invention

[0005] The systems, methods, and devices of the present disclosure each have some aspects, no single one of which is solely responsible for the desired attributes disclosed herein.

[0006] An innovative aspect of the subject matter described in the present disclosure can be implemented in a device. The device can include a light source system, a target detection system, and a control system configured to communicate with the light source system and the target detection system. In some embodiments, a mobile device (such as a wearable device, a cellular phone, etc.) can be or can include at least a part of the device.

[0007] The control system can include one or more general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or combinations thereof. The control system can be configured to receive target detection data from the target detection system. The control system can be configured to estimate the presence or absence of a biological target at least in part based on the target detection data. The control system can be configured to enable or disable the light source system at least in part based on the estimate of the presence or absence of the biological target.

[0008] In some examples, the light source system can include one or more lasers or laser diodes. According to some examples, the light source system can include one or more light-emitting diodes.

[0009] According to some examples, the control system can be further configured to control the light source system to emit one or more light pulses towards a biological target, and perform one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses. In some such examples, the device can include an ultrasonic receiver system, and the control system can be further configured to receive an ultrasonic receiver signal from the ultrasonic receiver system, where the ultrasonic receiver signal corresponds to the ultrasound caused by one or more responses of the biological target to the one or more light pulses. In some such examples, the control system can be further configured to provide a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof, at least in part based on the ultrasonic receiver signal.

[0010] In some examples, the target detection system can include a touch sensor system, a force sensing system, one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, an optical sensor system, one or more cameras, or a combination thereof. According to some examples in which the target detection system includes an optical sensor system, the control system can be further configured to control the intensity of the light emitted by the light source system, at least in part based on the optical sensor data from the optical sensor system.

[0011] According to some examples, the target detection system can include a liveness detection system. In some such examples, the liveness detection system can include a heart pulse detection system. In some such examples, the heart pulse detection system can include a camera system, an ultrasonic pulse detection system, a light pulse detection system, a photoacoustic pulse detection system, a photoplethysmography system, a microphone system, a ballistocardiogram sensor system, or a combination thereof.

[0012] In some examples, the target detection system can be configured to generate a first instance of target detection data at a first time and a second instance of target detection data at a second time. In some such examples, the time interval between the first time and the second time can be a target detection latency period. According to some such examples, the target detection latency period can be less than the pulse repetition frequency of the light source system.

[0013] Other innovative aspects of the subject matter described in this disclosure can be implemented in a method. The method can involve a control system receiving target detection data from a target detection system. The method can involve the control system estimating the presence or absence of a biological target at least in part based on the target detection data. The method can involve the control system enabling or disabling a light source system at least in part based on the estimate of the presence or absence of the biological target.

[0014] In some examples, the method can involve the control system controlling the light source system to emit one or more light pulses towards the biological target and performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses. In some examples, the method can involve the control system receiving an ultrasound receiver signal from an ultrasound receiver system, the ultrasound receiver signal corresponding to ultrasound caused by one or more responses of the biological target to the one or more light pulses. In some examples, the method can involve the control system providing a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof at least in part based on the ultrasound receiver signal.

[0015] According to some examples, the method can involve the target detection system generating a first instance of target detection data at a first time and a second instance of target detection data at a second time. In some such examples, the time interval between the first time and the second time can be a target detection delay period. According to some examples, the target detection delay period can be less than the pulse repetition frequency of the light source system.

[0016] Some or all of the methods described herein can be performed by one or more devices according to instructions (e.g., software) stored on a non-transitory medium. Such a non-transitory medium can include memory devices such as those described herein, including but not limited to random access memory (RAM) devices, read only memory (ROM) devices, etc. Thus, some innovative aspects of the subject matter described in this disclosure can be implemented in one or more non-transitory media having software stored thereon. The software can include instructions for controlling one or more devices to perform one or more of the disclosed methods.

[0017] According to some such examples, the method can involve the control system receiving target detection data from the target detection system. The method can involve the control system estimating the presence or absence of the biological target at least in part based on the target detection data. The method can involve the control system enabling or disabling the light source system at least in part based on the estimate of the presence or absence of the biological target.

[0018] In some examples, a method can involve a control system controlling a light source system to emit one or more light pulses towards a biological target and performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses. In some examples, a method can involve a control system receiving an ultrasonic receiver signal from an ultrasonic receiver system, the ultrasonic receiver signal corresponding to ultrasound caused by one or more responses of a biological target to one or more light pulses. In some examples, a method can involve a control system providing a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof based at least in part on the ultrasonic receiver signal.

[0019] According to some examples, a method can involve a target detection system generating a first instance of target detection data at a first time and a second instance of target detection data at a second time. In some such examples, the time interval between the first time and the second time can be a target detection delay period. According to some examples, the target detection delay period can be less than the pulse repetition frequency of the light source system.

[0020] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following drawings may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A An example of a blood pressure monitoring device based on Photoplethysmography (PPG) is shown.

[0022] Figure 1B An example of a blood pressure monitoring device based on photoacoustic plethysmography, which may be referred to herein as PAPG, is shown.

[0023] Figure 2 A block diagram shows example components of a device according to some disclosed implementations.

[0024] Figure 3 A flowchart shows examples of some disclosed operations.

[0025] Figure 4A An example of a Range-Gate Window (RGW) selected to receive sound waves emitted from different depth ranges is shown.

[0026] Figure 4B An example of multiple acquisition time delays selected to receive sound waves emitted from different depths is shown.

[0027] Figure 5A , Figure 5B and Figure 5C An example of a device configured to receive sound waves emitted from different depths is shown.

[0028] Figure 6 Examples of Heart Rate Waveform (HRW) features that may be extracted according to some embodiments are shown.

[0029] Figure 7 An example of a device that may be used in a system for estimating blood pressure based at least in part on Pulse Transit Time (PTT) is shown.

[0030] Figure 8 A cross-sectional side view of a diagrammatic representation of a portion of an artery 800 through which a pulse 802 propagates is shown.

[0031] Figure 9A An example ambulatory monitoring device designed to be worn around the wrist is shown in accordance with some embodiments.

[0032] Figure 9B An example ambulatory monitoring device 900 designed to be worn around a finger is shown in accordance with some embodiments.

[0033] Figure 9C An example ambulatory monitoring device 900 is shown that is designed to be placed on an earbud in accordance with some embodiments.

[0034] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION

[0035] For purposes of describing aspects of the present invention, the following description is directed to certain embodiments. However, those of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. Some of the concepts and examples provided in this disclosure are particularly applicable to blood pressure monitoring applications. However, some embodiments can also be applicable to other types of biosensing applications, as well as other fluid flow systems. The described embodiments can be implemented in any device, apparatus, or system that includes the devices disclosed herein. In addition, it is contemplated that the described embodiments can be included in or associated with a variety of electronic devices, such as but not limited to: mobile phones, cellular phones supporting multimedia Internet, mobile TV receivers, wireless devices, smart phones, smart cards, wearable devices such as bracelets, armbands, wristbands, rings, headbands, patches, etc., Bluetooth devices, personal data assistants (PDAs), wireless email receivers, handheld or portable computers, netbooks, notebooks, smartbooks, tablet computers, printers, copiers, scanners, fax devices, global positioning system (GPS) receivers / navigators, cameras, digital media players, gaming consoles, wristwatches, clocks, calculators, television monitors, flat panel displays, electronic reading devices (e.g., e-readers), mobile health devices, computer monitors, automotive displays (including odometer and speedometer displays, etc.), cockpit controls and / or displays, camera view displays (such as the display of a rearview camera in a vehicle), building structures, microwave ovens, refrigerators, stereo systems, cassette recorders or players, DVD players, CD players, VCRs, radios, portable memory chips, washing machines, dryers, washer / dryers, parking meters, vehicle doors, automatic or semi-automatic vehicles, drones, Internet of Things (IoT) devices, etc. Accordingly, these teachings are not intended to be limited to the specific embodiments depicted and described with reference to the accompanying drawings; rather, these teachings have broad applicability, which will be apparent to those of ordinary skill in the art

[0036] In recent years, a variety of different devices for biometric and biomedical applications, including health and wellness monitoring, biometric authentication, etc., have appeared on the market. Some such devices use high-intensity light, such as lasers. For example, some health monitoring systems and some biometric authentication systems may use high-intensity light for live detection, such as for heart pulse detection. Some devices can be configured to use high-intensity light for blood oxygen estimation, heart rate monitoring, blood pressure monitoring, etc. Some such devices can use high-intensity light for blood pressure monitoring based on photoplethysmogram (PPG) or photoacoustic plethysmogram (PAPG).

[0037] Compared with previously deployed devices such as cuff - based or catheter - based blood pressure measurement devices, this non - invasive device has various advantages. However, many of these devices are sold to the general public rather than medical professionals. As a result, there is an increased possibility of misuse or careless use, which may potentially cause high - intensity light (such as a laser) to be directed at a person's eyes or other vulnerable areas (such as a pet's eyes). This can cause discomfort or, in some cases, eye injury.

[0038] Some disclosed devices include a light source system, a target detection system; and a control system. The control system can be configured to receive target detection data from the target detection system and estimate the presence or absence of a biological target at least in part based on the target detection data. The control system can be configured to enable or disable the light source system at least in part based on the estimated presence or absence of the biological target. For example, if a biological target is detected, the control system can enable the light source system.

[0039] Certain embodiments of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. Some embodiments are configured to mitigate the risk of eye injury that might otherwise be caused by devices using high - intensity light (such as a laser). Some such embodiments can also save power by enabling the light source system only when a biological target is in place.

[0040] Figure 1A An example of a blood pressure monitoring device based on photoplethysmogram (PPG) is shown. Figure 1A Examples of arteries, veins, arterioles, venules, and capillaries of the circulatory system are shown, including those within finger 115. In Figure 1A the example shown, an electrocardiogram (ECG) sensor detects a proximal arterial pulse near the heart 116. Some examples of measuring the pulse transit time (PTT) based on the arterial pulse measured by two sensors are described below. In some embodiments, one of the sensors can be an ECG sensor.

[0041] According to Figure 1A the example shown, a light source including one or more lasers or light - emitting diodes (LEDs) emits light (in some examples, green, red, and / or near - infrared (NIR) light) that penetrates the tissue of finger 115 in the illuminated area. The reflections from these tissues detected by a photodetector can be used to detect volume changes in the blood corresponding to the heart rate waveform in the illuminated area of finger 115.

[0042] As Figure 1AAs shown in the heart rate waveform diagram 118, the capillary heart rate waveform 119 has a different shape and phase shift relative to the arterial heart rate waveform 117. In this simple example, the detected heart rate waveform 121 is a combination of the capillary heart rate waveform 119 and the arterial heart rate waveform 117. In some instances, the response of one or more other blood vessels can also be part of the heart rate waveform 121 detected by a PPG-based blood pressure monitoring device. The PPG-based blood pressure monitoring device is not optimal because the PPG superimposes data corresponding to the blood volume of all the illuminated blood vessels, and each in the blood vessels exhibits different and time-shifted blood volume changes.

[0043] Nonetheless, there are many deployed PPG-based blood pressure monitoring devices. Many such devices are configured to emit high-intensity light, such as lasers. Thus, such devices can be advantageously modified to implement the methods disclosed herein to mitigate risks such as eye injury that might otherwise be caused by such devices.

[0044] Figure 1B An example of a blood pressure monitoring device based on photoacoustic volume plethysmography is shown, which may be referred to herein as PAPG. Figure 1B is shown in connection with Figure 1A the same example of arteries, veins, arterioles, venules, and capillaries within the finger 115 shown in. In some examples, Figure 1B the light source shown in may be or may include one or more light-emitting diodes, one or more laser diodes, etc. In this example, as Figure 1A shown, the light source emits light (in some examples, green, red, and / or near-infrared (NIR) light) that penetrates the tissue of the finger 115 in the illuminated area.

[0045] In Figure 1B the example shown, the blood vessels (and the components of the blood itself) are heated by the incident light from the light source and emit sound waves. In this example, the emitted sound waves include ultrasonic waves. According to this embodiment, the acoustic emissions are detected by an ultrasonic receiver, which is a piezoelectric receiver in this example. The photoacoustic emissions from the illuminated tissue detected by the piezoelectric receiver can be used to detect volume changes corresponding to the heart rate waveform in the blood in the illuminated area of the finger 115. Although some of the shown illuminated tissue areas deviate from the areas shown as generating photoacoustic emissions, this is merely for illustrative convenience. It should be understood that the actually illuminated tissue will be those that generate photoacoustic emissions. Additionally, it can be understood that the maximum level of photoacoustic emissions generally occurs along the same axis as the maximum level of illumination. In some examples, the ultrasonic receiver can be an instance of the receiver system 202 described below with reference to Figure 2

[0046] Figure 1Aa PPG-based system and Figure 1B an important difference between the PAPG-based method is that Figure 1B the acoustic waves shown in Figure 1A travel much slower than the reflected light waves shown in Figure 1B Therefore, depth discrimination based on the arrival time of the acoustic waves shown in Figure 1A is possible, while depth discrimination based on the arrival time of the light waves shown in

[0047] may be impossible. This depth discrimination allows some of the disclosed embodiments to isolate the acoustic waves received from different blood vessels.

[0048] According to some such examples, this depth discrimination allows the arterial heart rate waveform to be distinguished from the venous heart rate waveform and other heart rate waveforms. Therefore, blood pressure estimation using the PAPG method based on depth discrimination is generally more accurate than blood pressure estimation using the PPG method.

[0048] A PAPG-based blood pressure monitoring device can be configured to emit high-intensity light, such as a laser. Therefore, such a device can be advantageously modified to implement the methods disclosed herein to reduce the risk of eye injury that might otherwise be caused by such a device.

[0049] Figure 2 FIG. shows a block diagram of an example component of a device according to some disclosed embodiments. In this example, device 200 includes a light source system 204, a target detection system 205, and a control system 206. Although Figure 2 not shown in Figure 2 , device 200 may include a substrate. Some embodiments of device 200 may include a receiver system 202, an interface system 208, and / or a display system 210.

[0050] This disclosure presents various examples of the receiver system 202, some of which may include an ultrasonic receiver system, an optical receiver system, or a combination thereof. In some embodiments that include an ultrasonic receiver system, the ultrasonic receiver and the ultrasonic transmitter may be combined in an ultrasonic transceiver. In some examples, the receiver system 202 may include a piezoelectric receiver layer, such as a PVDF polymer layer or a PVDF-TrFE copolymer layer. In some embodiments, a single piezoelectric layer may be used as an ultrasonic receiver. In some embodiments, other piezoelectric materials may be used in the piezoelectric layer, such as aluminum nitride (AlN) or lead zirconate titanate (PZT). In some examples, the receiver system 202 may include an array of ultrasonic transducer elements, such as an array of piezoelectric micromachined ultrasonic transducers (PMUTs), an array of capacitive micromachined ultrasonic transducers (CMUTs), etc. In some such examples, the piezoelectric receiver layer, the PMUT elements in a single-layer PMUT array, or the CMUT elements in a single-layer CMUT array may be used as both ultrasonic transmitters and ultrasonic receivers. According to some examples, the receiver system 202 may be or may include an ultrasonic receiver array. In some examples, the device 200 may include one or more independent ultrasonic transmitter elements. In some such examples, the ultrasonic transmitter may include an ultrasonic plane wave generator.

[0051] In some examples, the light source system 204 may include an array of light-emitting diodes. In some embodiments, the light source system 204 may include one or more laser diodes. According to some embodiments, the light source system 204 may include one or more vertical-cavity surface-emitting lasers (VCSELs). In some embodiments, the light source system may include one or more neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers. In some examples, the light source system 204 may be configured to emit a plurality of light pulses at a pulse repetition frequency between 10 Hz and 100 kHz.

[0052] According to some embodiments, the light source system may include at least one infrared, red, green, blue, white, or ultraviolet light-emitting diode. In some embodiments, the light source system 204 may include one or more laser diodes. For example, the light source system 204 may include at least one infrared, red, green, blue, white, or ultraviolet laser diode.

[0053] In some embodiments, the light source system 204 can be configured to emit light of various wavelengths, which can be selected to trigger acoustic wave emission mainly from a specific type of material. For example, since hemoglobin in blood strongly absorbs near-infrared light, in some embodiments, the light source system 204 can be configured to emit light of one or more wavelengths in the near-infrared range to trigger acoustic wave emission of hemoglobin. However, in some examples, the control system 206 can control the wavelength of the light emitted by the light source system 204 to preferentially induce acoustic waves in blood vessels, other soft tissues, and / or bones. For example, an infrared (IR) light-emitting diode LED can be selected and short pulses of IR light are emitted to irradiate a portion of the target object, and acoustic wave emission is generated and then detected by the receiver system 202. In another example, an IR LED and a red LED or other colors, such as green, blue, white, or ultraviolet (UV), can be selected and short pulses of light are emitted sequentially from each light source, and an ultrasonic image is obtained after light is emitted from each light source. In other embodiments, one or more light sources of different wavelengths can emit sequentially or simultaneously to generate acoustic emissions that can be detected by an ultrasonic receiver. Image data from the ultrasonic receiver can be combined to determine the location and type of materials in the target object, and the image data is obtained using light sources of different wavelengths and at different depths in the target object (e.g., varying RGD). Image contrast can occur when materials in the body generally absorb different wavelengths of light differently. When materials in the body absorb a specific wavelength of light, they can heat up differentially and generate acoustic wave emission with a sufficiently short pulse of light of sufficient intensity. Depth contrast can be obtained with light of different wavelengths and / or with different intensities of light at each selected wavelength. That is, continuous images can be obtained at a fixed RGD (which can correspond to a fixed depth in the target object) with varying light intensity and wavelength to detect materials and their locations within the target object. For example, hemoglobin, blood glucose, or blood oxygen in blood vessels within a target object such as a finger can be photoacoustically detected.

[0054] According to some embodiments, the light source system 204 can be configured to emit optical pulses with a pulse width less than about 100 nanoseconds. In some embodiments, the optical pulses can have a pulse width between about 10 nanoseconds and about 500 nanoseconds or greater. According to some examples, the light source system can be configured to emit a plurality of optical pulses at a pulse repetition frequency between 10 Hz and 100 kHz. Alternatively or additionally, in some embodiments, the light source system 204 can be configured to emit a plurality of optical pulses at a pulse repetition frequency between about 1 MHz and about 100 MHz. Alternatively or additionally, in some embodiments, the light source system 204 can be configured to emit a plurality of optical pulses at a pulse repetition frequency between about 10 Hz and about 1 MHz. In some examples, the pulse repetition frequency of the optical pulses can correspond to the acoustic resonance frequency of the ultrasonic receiver and the substrate. For example, a set of four or more optical pulses can be emitted from the light source system 204 at a frequency corresponding to the resonance frequency of the resonant acoustic cavity in the sensor stack, allowing for the build-up of received ultrasonic waves and higher composite signal intensity. In some embodiments, the light source system 204 can include a light source for detecting filtered light or light of a specific wavelength of a selected material. In some embodiments, the light source system can include light sources such as the red, green, and blue LEDs of a display, which can be enhanced with light sources of other wavelengths (such as IR and / or UV) and light sources of higher optical power. For example, a high-power laser diode or an electronic flash unit (e.g., an LED or a xenon flash unit) with or without a filter can be used for short-term illumination of a target object.

[0055] In this example, the device 200 includes a target detection system 205. The target detection system 205 can be configured to provide target detection data to the control system 206. The control system 206 can be configured to detect or estimate the presence of a biological target (such as a finger, wrist, or ear) at least in part based on the target detection data.

[0056] The specific components or assemblies of the target detection system 205 can vary according to specific embodiments. According to some examples, the target detection system 205 can be or can include a touch sensor system. The touch sensor system (if present) can be or can include a resistive touch sensor system, a surface capacitive touch sensor system, a projected capacitive touch sensor system, a surface acoustic wave touch sensor system, an infrared touch sensor system, any other suitable type of touch sensor system, or a combination thereof.

[0057] In some examples, the target detection system 205 can be or can include a force sensor system. The force sensor system (if present) can be or can include a piezoresistive sensor, a capacitive sensor, a thin film sensor (e.g., a polymer-based thin film sensor), other types of suitable force sensors, or a combination thereof. If the force sensor system includes a piezoresistive sensor, the piezoresistive sensor can include silicon, metal, polysilicon, glass, or a combination thereof. In some embodiments, the ultrasonic fingerprint sensor and the force sensor system can be mechanically coupled. In some such examples, the force sensor system can be integrated into the circuitry of the ultrasonic fingerprint sensor.

[0058] According to some examples, the target detection system 205 can be or can include one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, or a combination thereof.

[0059] In some examples, the target detection system 205 can be or can include an optical sensor system, one or more cameras, or a combination thereof. According to some examples in which the target detection system 205 includes an optical sensor system, the control system 206 can be configured to control the intensity of the light emitted by the light source system 204 at least in part based on optical sensor data from the optical sensor system.

[0060] According to some examples, the target detection system 205 can be or can include a liveness detection system. In some such examples, the target detection system 205 can include a heart pulse detection system. According to some examples, the heart pulse detection system can include a camera system, an ultrasonic pulse detection system, a light pulse detection system, a photoacoustic pulse detection system, a photoplethysmogram system, a microphone system, a ballistocardiogram sensor system, or a combination thereof. In some such examples, such as the ultrasonic pulse detection system, the light pulse detection system, the photoacoustic pulse detection system, and the photoplethysmogram system examples, the target detection system 205 can include at least a portion of the receiver system 202, the light source system 204, or a combination thereof, although the receiver system 202, the light source system 204, and the target detection system 205 are Figure 2 shown as separate blocks.

[0061] In some examples, the target detection system 205 can be configured to generate a first instance of target detection data at a first time and a second instance of target detection data at a second time. The time interval between the first time and the second time can be referred to herein as the target detection latency period. In some examples, the target detection latency period can be less than the pulse repetition frequency of the light source system 204.

[0062] The control system 206 may include one or more general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or combinations thereof. The control system 206 may also include (and / or be configured to communicate with) one or more memory devices, such as one or more random access memory (RAM) devices, read-only memory (ROM) devices, etc. Thus, the apparatus 200 may have a memory system including one or more memory devices, although the memory system is not shown in Figure 2 the figure. The control system 206 may be configured to receive and process data from the receiver system 202, for example, as described below. If the apparatus 200 includes an ultrasound transmitter, the control system 206 may be configured to control the ultrasound transmitter. In some embodiments, the functions of the control system 206 may be divided among one or more controllers or processors, such as a dedicated sensor controller and an application processor of a mobile device.

[0063] As described elsewhere herein, the control system 206 may be configured to control the light source system 204 at least in part based on target detection data from the target detection system 205. In some such examples, the control system 206 may be configured to estimate the presence or absence of a biological target at least in part based on the target detection data. In some such examples, the control system 206 may be configured to enable or disable the light source system at least in part based on the estimate of the presence or absence of the biological target.

[0064] In some embodiments, the control system may be configured to select light of one or more wavelengths for a plurality of light pulses. For example, because hemoglobin in blood strongly absorbs near-infrared light, in some embodiments, the control system may be configured to select light of one or more wavelengths in the near-infrared range to trigger acoustic emission of hemoglobin. According to some examples, the control system may be configured to select the light intensity associated with one or more selected wavelengths. For example, the control system may be configured to select light of one or more wavelengths and the light intensity associated with each selected wavelength to generate acoustic emission from one or more parts of a target object. In some examples, the control system may be configured to select light of one or more wavelengths to evaluate one or more characteristics of a target object, such as evaluating the blood oxygen level.

[0065] Some embodiments of apparatus 200 may include interface system 208. In some examples, interface system 208 may include a wireless interface system. In some embodiments, interface system 208 may include one or more interfaces between a user interface system, one or more network interfaces, control system 206, and memory system and / or one or more interfaces between control system 206 and one or more external device interfaces (e.g., ports or application processors). According to some examples in which interface system 208 is present and includes a user interface system, the user interface system may include a microphone system, a haptic feedback system, a voice command system, one or more displays, or a combination thereof.

[0066] According to some examples, apparatus 200 may include display system 210, and display system 210 includes one or more displays. For example, display system 210 may include one or more LED displays, such as one or more Organic LED (OLED) displays.

[0067] Apparatus 200 may be used in a variety of different scenarios, many examples of which are disclosed herein. For example, in some embodiments, a mobile device may include apparatus 200. In some embodiments, a wearable device may include apparatus 200. The wearable device may be, for example, a bracelet, an armband, a wristband, a watch, a ring, a headband, or a patch.

[0068] Figure 3 FIG. is a flowchart showing examples of some disclosed operations. Figure 3 The blocks (and the blocks of other flowcharts provided herein) may be performed, for example, by Figure 2 apparatus 200 of or a similar apparatus. Like other methods disclosed herein, Figure 3 the methods outlined in may include more or fewer blocks than indicated. In addition, the blocks of the methods disclosed herein are not necessarily performed in the order indicated. In certain cases, Figure 3 one or more of the blocks shown in may be performed simultaneously.

[0069] In this example, block 305 involves receiving target detection data from a target detection system by a control system. According to some examples, the target detection system may be an instance of target detection system 205, and the control system may be an instance of control system 206. In some examples, block 305 may involve receiving touch sensor data from a touch sensor system. According to some examples, block 305 may involve receiving force sensor data from a force sensor system. In some examples, block 305 may involve receiving data or receiving corresponding data from one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, an optical sensor system, one or more cameras, or a combination thereof.

[0070] In some examples, block 305 can involve receiving liveness data from a liveness detection system. According to some examples, block 305 can involve receiving heart pulse data from a heart pulse detection system.

[0071] According to this embodiment, block 310 involves estimating the presence or absence of a biological target by the control system based at least in part on the target detection data. The estimation of block 310 can vary according to a particular embodiment. The estimation of block 310 can vary according to a particular type or multiple particular types of the target detection data received from the target detection system. If the target detection data includes only force sensor data, then in some examples, the estimation of block 310 can involve assuming that the force sensor data corresponds to a biological target pressed on the device 200 in the area of the force sensor. If the target detection data includes only data from or corresponding to one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, etc., then in some examples, the estimation of block 310 can involve assuming that depending on whether the switch is closed or open, a wristband, a finger band, etc. has or has not been attached to the biological target.

[0072] If the target detection data includes only touch sensor data, then in some examples, the estimation of block 310 can involve assuming that the touch sensor data corresponds to a biological target touching the device 200 in the area of the touch sensor. However, if the target detection data includes touch sensor data from a touch sensor array, then the estimation of block 310 can involve determining the area corresponding to the touch sensor data. In some examples, block 310 can involve estimating whether the area corresponds to the shape and size of a finger or other digit.

[0073] If the target detection data includes optical sensor data, camera data, etc., then in some examples, the estimation of block 310 can involve estimating whether the image data, camera data, etc. from the optical sensor corresponds to a finger or other digit, a wrist, a person's ear, or other biological target. If the target detection data involves liveness data from a liveness detection system, then in some examples, the estimation of block 310 can involve estimating whether an object on or near the device near the liveness detection system is part of a living being.

[0074] According to some examples, the estimation of block 310 can involve estimating the position of a biological target with reference to at least a portion of a light source system. For example, if a portion of the light source system is configured to emit high-intensity light, such as a laser pulse, block 310 can involve estimating whether the biological target is placed on a portion of the device 200 corresponding to the portion of the light source system configured to emit high-intensity light. In some such examples, block 310 can involve estimating whether the biological target covers an area corresponding to the portion of the light source system configured to emit high-intensity light such that the high-intensity light is less likely to be directed towards the human eye or other vulnerable areas.

[0075] In this example, block 315 involves enabling or disabling the light source system by a control system and at least in part based on an estimate of the presence or absence of the biological target. According to some examples, if it is estimated in block 310 that the biological target is close to a portion of the device 200 corresponding to at least a portion of the light source system, block 315 can involve enabling the light source system. According to some examples, if it is estimated in block 310 that the biological target is covering a portion of the device 200 corresponding to the portion of the light source system configured to emit high-intensity light, block 315 can involve enabling the light source system. In some examples, if it is estimated in block 310 that the biological target is not close to a portion of the device 200 corresponding to at least a portion of the light source system, block 315 can involve disabling the light source system.

[0076] According to some examples, method 300 can involve (e.g., by a control system) controlling the light source system to emit one or more light pulses towards the biological target. In some such examples, method 300 can involve performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses. In some examples, method 300 can involve the control system receiving an ultrasound receiver signal corresponding to ultrasound caused by one or more responses of the biological target to the one or more light pulses from an ultrasound receiver system. According to some examples, method 300 can involve the control system providing a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof at least in part based on the ultrasound receiver signal.

[0077] According to some examples, a control system can be configured to discriminate between a venous heart rate waveform and an arterial heart rate waveform by obtaining a depth discrimination signal. According to some such examples, receiving a signal from a piezoelectric receiver involves obtaining a depth discrimination signal by applying first through Nth acquisition time delays and receiving first through Nth signals during first through Nth acquisition time windows, each of the first through Nth acquisition time windows occurring after a corresponding one of the first through Nth acquisition time delays, where N is an integer greater than 1. The control system can be configured to determine at least in part a first subset of detected heart rate waveforms and a second subset of detected heart rate waveforms based on the depth discrimination signal.

[0078] According to some examples, a control system can be configured to distinguish between a venous heart rate waveform and an arterial heart rate waveform by obtaining a depth discrimination signal. Figure 4A An example of a range-gated window (RGW) selected to receive acoustic waves emitted from a series of different depths is shown. The acquisition time delay or range-gated delay (labeled “RGD” in Figure 4B is measured starting from the start time t1 of the photoexcitation signal 405 shown in graph 400. For example, the RGD can be selected to correspond to the time it takes for a photoacoustic emission to reach the receiver from the shallowest target of interest, e.g., as described below with reference to Figure 5A and Figure 5B . Thus, the RGD can depend on the particular arrangement of the device used to receive the photoacoustic emission, including the thickness of the layer between the target object and the receiver and the speed of sound in the layer between the target object and the receiver. Graph 401 depicts the time after the RGD during which the emitted acoustic waves can be received and sampled by an ultrasonic receiver during the acquisition time window (also referred to as the range-gated window or range-gated width) of the RGW. In some embodiments, the RGW can be 10 microseconds. Other embodiments can have larger or smaller RGWs.

[0079] In some examples, a depth discrimination signal can be obtained by a process of dividing the acoustic waves received during the RGW into a plurality of small time windows. Each of the time windows can correspond to a depth range within the target object from which the acoustic waves are received. In some examples, the depth range or thickness of each layer can be 0.5 millimeters. Assuming a speed of sound of 1.5 millimeters / microsecond, each 0.5 - millimeter layer will correspond to a time slot of approximately 0.33 microseconds. However, the depth range can vary according to a particular embodiment.

[0080] According to some alternative examples, receiving the signal from the piezoelectric receiver involves obtaining a depth-discriminated signal by applying first to Nth acquisition time delays, and receiving the first to Nth signals during first to Nth acquisition time windows, each of the first to Nth acquisition time windows occurring after a corresponding one of the first to Nth acquisition time delays, where N is an integer greater than 1. The control system may be configured to determine a first subset of detected heart rate waveforms and a second subset of detected heart rate waveforms based at least in part on the depth-discriminated signal.

[0081] Figure 4B Examples are shown in which multiple acquisition time delays are selected to receive acoustic waves emitted from different depths. In these examples, the acquisition time delays (which are Figure 4B Each of the delays (denoted as range gate delays or RGD) is a time t from the start of the optical excitation signal 405 shown in the graph 400. l The graph 410 depicts an emitted acoustic wave (the received wave (1) is one example) which may be received by the ultrasound sensor array at an acquisition time delay RGD1 and sampled during an acquisition time window (also referred to as a range gate window or range gate width) of RGW1. Such an acoustic wave will typically emanate from a relatively shallow portion of a target object that is close to or positioned on a platen of a biometric system.

[0082] Graph 415 depicts a transmitted sound wave (received wave (2) is one example) received by the ultrasound sensor array at acquisition time delay RGD2 (where RGD2>RGD1) and sampled during acquisition time window RGW2. Such sound waves will typically emanate from a relatively deeper portion of the target object.

[0083] Graph 420 depicts the transmitted acoustic wave (the received wave (n) is one example) delayed by RGD at the acquisition time n (RGD n >RGD2>RGD1) is received and nThe range gate width is sampled during the acquisition time window of the target object. Such sound waves will typically emanate from a deeper portion of the target object. The range gate delay is typically an integer multiple of the clock period. For example, a clock frequency of 128 MHz has a clock period of 7.8125 nanoseconds, while the RGD can range from less than 10 nanoseconds to more than 2000 nanoseconds. Similarly, the range gate width can also be an integer multiple of the clock period, but is typically much shorter than the RGD (e.g., less than about 50 nanoseconds) to capture the return signal while maintaining good axial resolution. In some embodiments, the acquisition time window (e.g., RGW) can be between 175 nanoseconds and 320 nanoseconds or more. In some examples, the RGW can be more or less nanoseconds, for example, in the range of 25 nanoseconds to 1000 nanoseconds.

[0084] Figure 5A , Figure 5B and Figure 5C An example of a device configured to receive sound waves emitted from different depths is shown. Figures 5A - 5C The device shown is Figure 2 As with other embodiments shown and described herein, Figures 5A - 5C The types of elements, arrangements of elements, and dimensions of elements shown in the drawings are shown as examples only.

[0085] According to these examples, the apparatus 200 includes an ultrasound receiver, which is an example of a receiver system 202, a light source system 204 (which may include an LED in some examples), an object detection system 505, and a control system ( Figures 5A - 5C In these examples, the target detection system 505 is referenced Figure 2 An example of the target detection system 205 is described. Figure 5A , the device 200 includes a beam splitter 501 on a side 502 on which the light source system 204 is mounted. In this example, a finger 506 rests on an adjacent surface 504 of the device 200 and is detected by an object detection system 505. According to this example, the object detection system 505 provides object detection data to the control system indicating that the finger 506 is in contact with the surface 504. Based on the object detection data, the control system estimates that a biological target is present on the surface 504 and enables the light source system 204.

[0086] Figure 5A 506. For this and other embodiments, the range gate delay can be selected, for example, to correspond to the time required for the photoacoustic emission to reach the receiver from the shallowest target of interest. For example, in one configuration of the device 200 using a 12.7 mm beam splitter between the finger 506 and the ultrasound receiver 202 (Figure 5A In the RX), the finger surface signal will arrive in the time it takes for the acoustic wave to travel through the entire beam splitter. Using the acoustic velocity of borosilicate glass of 5500 m / s as the approximate acoustic velocity of the beam splitter, where the size of the beam splitter is 12.7 mm, this time becomes 12.7 mm / 5500 m / s or 2.3 microseconds. Thus, a range gating delay of 2.3 microseconds corresponds to the surface of finger 506. For example, to travel 1 mm into finger 506, using the acoustic velocity of tissue now at 1.5 mm / microsecond, this time becomes 1 mm / 1.5 mm / microsecond or approximately 0.67 microseconds. Thus, a range gating delay of approximately 2.97 microseconds (2.3 microseconds + 0.67 microseconds) will cause the ultrasonic receiver 202 to start sampling the acoustic waves reflected from a depth of approximately 1 mm below the outer surface of finger 506.

[0087] Figure 5B An acoustic signal corresponding to the photoacoustic emission of tissue (e.g., blood and blood vessels) within finger 506 caused by light entering finger 506 is shown. In Figure 5B the example shown, the acoustic signals originate from different depths (depths 508a, 508b, and 508c) within finger 506. Thus, the travel times t1, t2, and t3 from depths 508a, 508b, and 508c to the ultrasonic receiver 202 are also different: in this example, t3 > t2 > t1. Thus, multiple acquisition time delays can be selected to receive the acoustic waves emitted from depths 508a, 508b, and 508c, for example, as shown in Figure 4B and as described above.

[0088] In Figure 5C the embodiment shown, the positions of the light source system 204 and the receiver system 202 are reversed compared to the positions shown in Figure 5A According to this embodiment, the device 200 includes a translucent light guide 510 through which light from the light source system 204 can pass. In this embodiment, the ultrasound generated within finger 506 is reflected by the air / light guide interface towards the receiver system 202. In this example, finger 506 rests on the adjacent surface 504 of the device 200 and is detected by the target detection system 505. According to this example, the target detection system 505 provides target detection data to the control system indicating that finger 506 is in contact with surface 504. Based on the target detection data, the control system estimates the presence of a biological target on surface 504 and enables the light source system 204.

[0089] Figure 6 An example of the heart rate waveform (HRW) features that can be extracted according to some embodiments is shown. Figure 6The horizontal axis represents time, and the vertical axis represents signal amplitude. The cardiac period is indicated by the time between adjacent peaks of the HRW. The systolic and diastolic time intervals are indicated below the horizontal axis. During the systolic phase of the cardiac cycle, as the pulse propagates along the artery through a particular location, the arterial wall expands according to the pulse waveform and the elastic properties of the arterial wall. Along with the expansion is a corresponding increase in the volume of blood at the particular location or region, and along with the increase in the volume of blood is a related change in one or more characteristics in the region. Conversely, during the diastolic phase of the cardiac cycle, the blood pressure in the artery decreases and the arterial wall contracts. Along with the contraction is a corresponding decrease in the volume of blood at the particular location, and along with the decrease in the volume of blood is a related change in one or more characteristics in the region.

[0090] Figure 6 The HRW features shown in are related to the widths of the systolic and / or diastolic portions of the HRW curve at different "heights" represented as a percentage of the maximum amplitude. For example, the SW50 feature is the width of the systolic portion of the HRW curve at a "height" of 50% of the maximum amplitude. In some embodiments, the HRW features used for blood pressure estimation may include some or all of the SW10, SW25, SW33, SW50, SW66, SW75, DW10, DW25, DW33, DW50, DW66, and DW75 HRW features. In other embodiments, additional HRW features may be used for blood pressure estimation. In some instances, such additional HRW features may include the sum and ratio of SW and DW at one or more "heights", e.g., (DW75+SW75), DW75 / SW75, (DW66+SW66), DW66 / SW66, (DW50+SW50), DW50 / SW50, (DW33+SW33), DW33 / SW33, (DW25+SW25), DW25 / SW25, and / or (DW10+SW10), DW10 / SW10. Other embodiments may use other HRW features for blood pressure estimation. In some instances, such additional HRW features may include sums, differences, ratios, and / or other operations based on more than one "height", such as (DW75+SW75) / (DW50+SW50), (DW50+SW50) / (DW10+SW10), etc.

[0091] Figure 7An example of a device in a system that can be used to estimate blood pressure based at least in part on Pulse Transit Time (PTT) is shown. As with other figures provided herein, the number, type, and arrangement of elements are presented by way of example only. According to this example, system 700 includes at least two sensors. In this example, system 700 includes at least an electrocardiogram sensor 705 and a device 710 configured to be mounted on the finger of a person 701. In this example, device 710 is or includes a device configured to perform at least some of the PAPG methods disclosed herein. For example, device 710 may be or may include Figure 2 device 200 or a similar device.

[0092] As represented in graph 720, PAT includes two components, the Pre-Ejection Period (PEP) (the time required to convert an electrical signal into a mechanical pumping force and isovolumetric contraction to open the aortic valve) and PTT. The start time of PAT can be estimated based on the QRS complex—the electrical signal characteristic of the electrical stimulation of the ventricle. As shown in graph 720, in this example, the start of the Pulse Arrival Time (PAT) can be calculated based on the R-wave peak measured by electrocardiogram sensor 705, and the end of PAT can be detected via the analysis of the signal provided by device 710. In this example, it is assumed that the end of PAT corresponds to the intersection between the tangent of the local minimum detected by device 710 and the tangent of the maximum slope / first derivative of the sensor signal after the time of the minimum.

[0093] There are many known algorithms for blood pressure estimation based on PTT and / or PAT, some of which are summarized in Table 1 of Sharma, M., et al., "Cuffless and Continuous Blood Pressure Monitoring: A Review of Methods" ("Sharma"), in Technologies 2017, 5, 21 by the Multidisciplinary Digital Publishing Institute (MDPI), and which is described in the corresponding text on pages 5-10 of Sharma, both of which are incorporated herein by reference.

[0094] Other embodiments of system 700 may not include electrocardiogram sensor 705. In some such embodiments, a device 715 configured to be mounted on the wrist of a person 701 may be or may include a device configured to perform at least some of the PAPG methods disclosed herein. For example, device 715 may be or may include Figure 2Device 200 or a similar device. According to some such examples, device 715 may include a light source system and two or more ultrasonic receivers. Examples are described below with reference to FIGS. 17A - 17C. In some examples, device 715 may include at least one ultrasonic receiver array.

[0095] Figure 8 A cross-sectional side view showing a graphical representation of a portion of artery 800 through which pulse 802 propagates. Figure 8 The boxed arrows in show the direction of blood flow and pulse propagation. As shown, the propagating pulse 802 causes strain in the arterial wall 804, which manifests in the form of an expansion of the diameter (and thus cross-sectional area) of the arterial wall - referred to as "distension". The spatial length L of the actual propagating pulse along the artery (in the direction of blood flow) is typically comparable to the length of the limb, such as the distance from the subject's shoulder to the subject's wrist or finger, and is typically less than 1 meter (m). However, the length L of the propagating pulse can vary from subject to subject and, for a given subject, can vary significantly over time depending on various factors. The spatial length L of the pulse generally decreases with increasing distance from the heart until the pulse reaches the capillaries.

[0096] As described above, some particular embodiments relate to devices, systems, and methods for estimating blood pressure or other cardiovascular characteristics based on an estimate of an arterial dilation waveform. Unless otherwise indicated, the terms "estimate," "measure," "calculate," "infer," "derive," "evaluate," "determine," and "monitor" may be used interchangeably herein, as appropriate. Similarly, derivatives of the roots of these terms may also be used interchangeably, as appropriate; for example, the terms "to estimate," "to measure," "to calculate," "to infer," and "to determine" may also be used interchangeably herein. In some embodiments, the Pulse Wave Velocity (PWV) of a propagating pulse may be estimated by measuring the Pulse Transit Time (PTT) of the pulse as it propagates from a first physical location along an artery to a second, more distal physical location along the artery. It should be understood that this PTT is different from the PTT described above with reference to FIG. 15. However, either version of the PTT may be used for the purpose of blood pressure estimation. Assuming that the physical distance ΔD between the first physical location and the second physical location is determinable, the PWV may be estimated as the quotient of the physical spatial distance ΔD traveled by the pulse divided by the time (PTT) it takes for the pulse to traverse the physical spatial distance ΔD. Generally, a first sensor located at the first physical location is used to determine the start time (also referred to herein as the "first temporal location") at which the pulse arrives at or propagates through the first physical location. A second sensor at the second physical location is used to determine the end time (also referred to herein as the "second temporal location") at which the pulse arrives at or propagates through the second physical location and continues through the remainder of the arterial branch. In such an example, the PTT represents the time distance (or time difference) between the first temporal location and the second temporal location (start time and end time).

[0097] The fact that the arterial dilation waveform measurements are performed at two different physical locations means that the estimated PWV inevitably represents an average over the entire path distance ΔD through which the pulse propagates between the first physical location and the second physical location. More specifically, the PWV generally depends on a number of factors, including the density ρ of the blood, the stiffness E (or conversely, the elasticity) of the arterial wall, the arterial diameter, the thickness of the arterial wall, and the blood pressure. Because the arterial wall elasticity and the baseline resting diameter (e.g., the diameter at the end of ventricular diastole) vary significantly throughout the arterial system, the PWV estimate obtained from PTT measurements is an inherent average (averaged over the entire path length ΔD between the two locations where the measurements are performed).

[0098] In traditional methods for obtaining PWV, the start time of a pulse has been obtained at the heart using an electrocardiogram (ECG) sensor that detects electrical signals from the heart. For example, the start time can be estimated based on the QRS complex, which is the electrical signal signature of the electrical stimulation of the heart ventricles. In this method, a different sensor located at a second location (e.g., a finger) is typically used to obtain the end time of the pulse. As will be understood by those of ordinary skill in the art, there are many arterial discontinuities, branches, and variations along the entire path length from the heart to the finger. Along each segment of the entire path length from the heart to the finger, the PWV can vary by as much as or more than an order of magnitude. Therefore, PWV estimation based on such a long path length is unreliable.

[0099] In various embodiments described herein, a PTT estimate is obtained based on measurements associated with arterial dilation signals (also referred to as "arterial dilation data" or more generally as "sensor data"), which are obtained by each of a first arterial dilation sensor 806 and a second arterial dilation sensor 808 located respectively near a first physical location and a second physical location along an artery of interest. In some particular embodiments, the first arterial dilation sensor 806 and the second arterial dilation sensor 808 are advantageously positioned near the first physical location and the second physical location between which arterial properties of the artery of interest, such as wall elasticity and diameter, can be considered or assumed to be relatively constant. In this way, the PWV calculated based on the PTT estimate is more representative of the actual PWV along a particular segment of the artery. In turn, the blood pressure P estimated based on the PWV is more representative of the true blood pressure. In some embodiments, the magnitude of the separation distance ΔD between the first arterial dilation sensor 806 and the second arterial dilation sensor 808 (and thus the distance between the first location and the second location along the artery) can range from about 1 centimeter (cm) to several tens of centimeters - long enough to distinguish the pulse arriving at the first physical location from the pulse arriving at the second physical location, but close enough to provide sufficient assurance of arterial consistency. In some specific embodiments, the distance ΔD between the first arterial dilation sensor 806 and the second arterial dilation sensor 808 can range from about 1 cm to about 30 cm, and in some embodiments, is less than or equal to about 20 cm, and in some embodiments, is less than or equal to about 10 cm, and in some specific embodiments, is less than or equal to approximately 5 cm. In some other embodiments, the distance ΔD between the first arterial dilation sensor 806 and the second arterial dilation sensor 808 can be less than or equal to 1 cm, for example, about 0.1 cm, about 0.25 cm, about 0.5 cm, or about 0.75 cm. As a reference, a typical PWV can be about 15 meters per second (m / s). Using a dynamic monitoring device in which the first arterial dilation sensor 806 and the second arterial dilation sensor 808 are separated by a distance of about 5 cm, and assuming a PWV of about 15 m / s implies a PTT of about 3.3 milliseconds (ms).

[0100] The magnitude of the distance ΔD between the first arterial dilation sensor 806 and the second arterial dilation sensor 808 can be pre-programmed respectively into a memory within the monitoring device incorporating the sensors (e.g., such as the memory of the control system 206 referred to above or a memory configured to communicate with the control system 206). As will be understood by those of ordinary skill in the art, in such an embodiment, the spatial length L of the pulse can be greater than the distance ΔD from the first arterial dilation sensor 806 to the second arterial dilation sensor 808. Thus, although Figure 2 described above, the spatial length L of the pulse can be greater than the distance ΔD from the first arterial dilation sensor 806 to the second arterial dilation sensor 808. Thus, althoughFigure 8 The illustrated pulse 802 shown in FIG. has a spatial length L equivalent to the distance between the first arterial dilation sensor 806 and the second arterial dilation sensor 808, but in reality each pulse can typically have a spatial length L that is even much larger (e.g., about an order of magnitude or more) than the distance ΔD between the first arterial dilation sensor 806 and the second arterial dilation sensor 808.

[0101] Sensing Architecture and Topology

[0102] In some embodiments of the dynamic monitoring device disclosed herein, both the first arterial dilation sensor 806 and the second arterial dilation sensor 808 are sensors of the same sensor type. In some such embodiments, the first arterial dilation sensor 806 and the second arterial dilation sensor 808 are the same sensors. In such embodiments, each of the first arterial dilation sensor 806 and the second arterial dilation sensor 808 utilizes the same sensor technology, which has the same sensitivity to the arterial dilation signal caused by the propagating pulse, and has the same time delay and sampling characteristics. In some embodiments, each of the first arterial dilation sensor 806 and the second arterial dilation sensor 808 is configured for photoacoustic plethysmogram (PAPG) sensing, for example, as disclosed elsewhere herein. Some such embodiments include a light source system and two or more ultrasonic receivers, which can be Figure 2 instances of the light source system 204 and the receiver system 202. In some embodiments, each of the first arterial dilation sensor 806 and the second arterial dilation sensor 808 is configured for ultrasonic sensing by transmitting ultrasonic signals and receiving the corresponding reflections. In some alternative embodiments, each of the first arterial dilation sensor 806 and the second arterial dilation sensor 808 can be configured for impedance plethysmography (IPG) sensing, also known as bioimpedance sensing in biomedical scenarios. In various embodiments, regardless of the type of sensor utilized, each of the first arterial dilation sensor 806 and the second arterial dilation sensor 808 broadly functions to capture and provide arterial dilation data indicative of the arterial dilation signal, which is generated by the propagation of the pulse in the portion of the artery located near the respective sensor. For example, the arterial dilation data can be provided to the processor in the form of a voltage signal, which is generated or received by the sensor based on the ultrasonic signal or impedance signal sensed by the respective sensor.

[0103] As described above, during the systolic phase of the cardiac cycle, when the pulse propagates along the artery through a specific location, the arterial wall expands according to the pulse waveform and the elastic properties of the arterial wall. Along with the expansion is a corresponding increase in the volume of blood at the specific location or region, and along with the increase in the volume of blood is a related change in one or more characteristics in the region. Conversely, during the diastolic phase of the cardiac cycle, the blood pressure in the artery decreases, and the arterial wall contracts. Along with the contraction is a corresponding decrease in the volume of blood at the specific location, and along with the decrease in the volume of blood is a related change in one or more characteristics in the region.

[0104] In the context of bioimpedance sensing (or impedance plethysmography), the blood in the artery has a greater electrical conductivity than the surrounding or adjacent skin, muscle, fat, tendon, ligament, bone, lymph, or other tissues. The susceptance (and dielectric constant) of the blood also differs from that of other types of surrounding or nearby tissues. When the pulse propagates through a specific location, the corresponding increase in the volume of blood at the specific location results in an increase in electrical conductivity (and more generally, an increase in admittance, or equivalently a decrease in impedance). Conversely, during the diastolic phase of the cardiac cycle, the corresponding decrease in the volume of blood at the specific location results in an increase in resistivity (and more generally, an increase in impedance, or equivalently a decrease in admittance).

[0105] Bioimpedance sensors typically operate by applying an electrical excitation signal of an excitation carrier frequency to the region of interest via two or more input electrodes and detecting an output signal via two or more output electrodes. In some more specific embodiments, the electrical excitation signal is a current signal injected into the region of interest via the input electrodes. In some such embodiments, the output signal is a voltage signal representative of the voltage response of the tissue in the region of interest to the applied excitation signal. The detected voltage response signal is affected by the different electrical properties (in some instances time-varying electrical properties) of the various tissues through which the injected excitation current signal passes. In some embodiments in which the bioimpedance sensor is operable to monitor blood pressure, heart rate, or other cardiovascular characteristics, the detected voltage response signal is modulated by the time-varying impedance (or conversely, admittance) amplitude and phase of the underlying artery, which fluctuates in synchrony with the user's heartbeat, as described above. To determine various biometric characteristics, information in the detected voltage response signal is typically demodulated from the excitation carrier frequency component using various analog or digital signal processing circuits, which may include passive and active components.

[0106] In some examples incorporating an ultrasonic sensor, the measurement of arterial dilation can involve introducing ultrasound into a limb, finger, etc., e.g., directed at an artery via one or more ultrasonic transducers. Such an ultrasonic sensor is also configured to receive waves that are at least partially reflective of the introduced wave. The reflected waves can include scattered waves, specularly reflected waves, or both scattered and specularly reflected waves. The reflected waves provide information about the arterial wall and thus information about arterial dilation. In some alternative embodiments, light can be introduced into a limb, finger, etc., directed at an artery, and ultrasound generated by biological tissue in response to the light can be received by an ultrasound receiver system.

[0107] In some embodiments, regardless of the type of sensors used for the first arterial dilation sensor 806 and the second arterial dilation sensor 808, both the first arterial dilation sensor 806 and the second arterial dilation sensor 808 can be arranged, assembled, or otherwise included within a single housing of a single dynamic monitoring device. As described above, the housing and other components of the monitoring device can be configured such that when the monitoring device is secured or otherwise physically coupled to a subject, the first arterial dilation sensor 806 and the second arterial dilation sensor 808 are in contact with or near the user's skin at a first location and a second location, respectively, the first location and the second location being separated by a distance ΔD, and in some embodiments, along a segment of an artery along which various arterial characteristics can be assumed to be relatively constant. In various embodiments, the housing of the dynamic monitoring device is a wearable housing, or is incorporated into or integrated with a wearable housing. In some specific embodiments, the wearable housing includes (or is connected to) a physical coupling mechanism for removably and non-invasively attaching to the user. The housing can be formed using any of a variety of suitable manufacturing processes, including injection molding and vacuum forming, etc. Additionally, the housing can be made of any of a variety of suitable materials, including but not limited to plastics, metals, glass, rubber, and ceramics, or combinations of these or other materials. In certain embodiments, the housing and the coupling mechanism are capable of full dynamic use. In other words, some embodiments of the wearable monitoring devices described herein are non-invasive, non-physically inhibiting, and generally do not restrict the unrestrained movement of the subject's arm or leg, such that cardiovascular characteristics, such as blood pressure, can be continuously or periodically monitored even when the subject is moving or otherwise engaged in physical activity. Thus, the dynamic monitoring device facilitates and enables long-term wear and monitoring (e.g., over days, weeks, or a month or longer without interruption) of one or more biometric characteristics of interest to obtain a better portrait of these characteristics over an extended duration, and generally, a better portrait of the user's health.

[0108] In some embodiments, the dynamic monitoring device can be positioned around a user's wrist with a strap or band similar to a watch or a fitness / activity tracker. Figure 9A An example dynamic monitoring device 900 designed to be worn around the wrist according to some embodiments is shown. In this example, the dynamic monitoring device 900 is Figure 2 an instance of the device 200. In the example shown, the monitoring device 900 includes a housing 902 integrally formed with, coupled to, or otherwise integrated with the band 904. In some instances, the first arterial dilation sensor 906 and the second arterial dilation sensor 908 can each include portions of the receiver system 202 and the light source system 204 described above with reference to Figure 2 In this example, the dynamic monitoring device 900 is coupled around the wrist such that the first arterial dilation sensor 906 and the second arterial dilation sensor 908 within the housing 902 are each positioned along a segment of the radial artery 910 (note that the sensors are typically hidden from the perspective of the outer or external surface of the housing facing the subject when the monitoring device is coupled to the subject, but are exposed on the inner surface of the housing to enable the sensors to obtain measurements from the underlying artery through the subject's skin). Also as shown, the first arterial dilation sensor 906 and the second arterial dilation sensor 908 are separated by a fixed distance ΔD. In some other embodiments, the dynamic monitoring device 900 can be similarly designed or adapted to be positioned around the forearm, upper arm, ankle, calf, thigh, or finger (collectively referred to hereinafter as "limb") using a strap or band.

[0109] According to this example, the dynamic monitoring device 900 includes target detection system components 905a and 905b, each of which is Figure 2 an instance of the target detection system 205. In this example, the target detection system component 905a is configured to provide target detection data to a control system (not shown) indicating whether the band 904 is fastened. In some examples, the target detection system component 905a can be or can include one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, or a combination thereof.

[0110] In this example, the target detection system component 905b is configured to provide target detection data to the control system indicating whether an object (such as a person's wrist) is close to the housing 902. In some examples, the target detection system component 905b can be or can include a touch sensor system, a force sensor system, an optical sensor system, one or more cameras, or a combination thereof. According to some examples, the first arterial dilation sensor 906, the second arterial dilation sensor 908, or both can include components of the target detection system 205. In some such examples, the first arterial dilation sensor 906, the second arterial dilation sensor 908, or both can include a touch sensor system, a force sensor system, an optical sensor system, one or more cameras, or a combination thereof.

[0111] According to some examples in which the target detection system component 905b (or other components of the target detection system 205) includes an optical sensor system, the control system can be configured to control the intensity of the light emitted by the light source system 204 at least in part based on optical sensor data from the optical sensor system. As described above, in this example, the first arterial dilation sensor 906 and the second arterial dilation sensor 908 each include portions of the receiver system 202 and the light source system 204 described above Figure 2 Therefore, in some examples in which the target detection system component 905b (or other components of the target detection system 205) includes an optical sensor system, the control system can be configured to control the intensity of the light emitted by the first arterial dilation sensor 906, the second arterial dilation sensor 908, or both at least in part based on optical sensor data from the optical sensor system.

[0112] Figure 9B An example dynamic monitoring device 900 designed to be worn around a finger according to some embodiments is shown. In some instances, the first arterial dilation sensor 906 and the second arterial dilation sensor 908 can each include portions of the receiver system 202 and the light source system 204 described above Figure 2 Therefore, in some examples in which the target detection system component 905b (or other components of the target detection system 205) includes an optical sensor system, the control system can be configured to control the intensity of the light emitted by the first arterial dilation sensor 906, the second arterial dilation sensor 908, or both at least in part based on optical sensor data from the optical sensor system.

[0113] According to this example, the dynamic monitoring device 900 includes target detection system components 905a and 905b, each of which is an Figure 2 instance of the target detection system 205. In this example, the target detection system component 905a is configured to provide target detection data to a control system (not shown) indicating whether the strap 904 is fastened. In some examples, the target detection system component 905a can be or can include one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, or a combination thereof.

[0114] In this example, the target detection system component 905b is configured to provide target detection data to the control system indicating whether an object (such as a finger or other digit) is close to the housing 902. In some examples, the target detection system component 905b may be or may include a touch sensor system, a force sensor system, an optical sensor system, one or more cameras, or a combination thereof. According to some examples, the first arterial dilation sensor 906, the second arterial dilation sensor 908, or both may include components of the target detection system 205. In some such examples, the first arterial dilation sensor 906, the second arterial dilation sensor 908, or both may include a touch sensor system, a force sensor system, an optical sensor system, one or more cameras, or a combination thereof.

[0115] According to some instances in which one or more of the target detection system components 905b (or other components of the target detection system 205) include an optical sensor system, the control system may be configured to control the intensity of the light emitted by the light source system 204 at least in part based on the optical sensor data from the optical sensor system. As described above, in this example, the first arterial dilation sensor 906 and the second arterial dilation sensor 908 each include portions of the receiver system 202 and the light source system 204 described above Figure 2 Therefore, in some examples in which one or more of the target detection system components 905b (or other components of the target detection system 205) include an optical sensor system, the control system may be configured to control the intensity of the light emitted by the first arterial dilation sensor 906, the second arterial dilation sensor 908, or both at least in part based on the optical sensor data from the optical sensor system.

[0116] In some other embodiments, the dynamic monitoring device disclosed herein may be positioned on the area of interest of the user without using a strap or band. For example, the first arterial dilation sensor 906 and the second arterial dilation sensor 908, as well as other components of the monitoring device, may be encapsulated in a housing that is fixed to the skin of the area of interest of the user using an adhesive or other suitable attachment mechanism (such as a "patch" monitoring device).

[0117] Figure 9C An example dynamic monitoring device 900 designed to be placed on an earbud is shown according to some embodiments. According to this example, the dynamic monitoring device 900 is coupled to the housing of the earbud 920. In some instances, the first arterial dilation sensor 906 and the second arterial dilation sensor 908 may each include portions of the receiver system 202 and the light source system 204 described above Figure 2 described.

[0118] According to this example, the dynamic monitoring device 900 includes a target detection system component 905b, which isFigure 2 An example of the target detection system 205. In this example, the target detection system component 905b is configured to provide target detection data to the control system, indicating whether an object, such as a human ear, is close to the housing 902. In some examples, the target detection system component 905b may be or may include a touch sensor system, a force sensor system, an optical sensor system, one or more cameras, or a combination thereof.

[0119] Example embodiments are described in the following numbered clauses:

[0120] 1. An apparatus, comprising: a light source system; a target detection system; and a control system configured to communicate with the light source system and the target detection system, the control system further configured to: receive target detection data from the target detection system; estimate the presence or absence of a biological target at least in part based on the target detection data; and enable or disable the light source system at least in part based on the estimate of the presence or absence of the biological target.

[0121] 2. The apparatus according to clause 1, wherein the light source system includes one or more lasers or laser diodes.

[0122] 3. The apparatus according to clause 1 or clause 2, wherein the light source system includes one or more light emitting diodes.

[0123] 4. The apparatus according to any one of clauses 1-3, wherein the control system is further configured to control the light source system to emit one or more light pulses towards the biological target and perform one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses.

[0124] 5. The apparatus according to clause 4, further comprising an ultrasonic receiver system, wherein the control system is further configured to receive an ultrasonic receiver signal corresponding to the ultrasound caused by one or more responses of the biological target to the one or more light pulses from the ultrasonic receiver system.

[0125] 6. The apparatus according to clause 5, wherein the control system is further configured to provide a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof at least in part based on the ultrasonic receiver signal.

[0126] 7. The apparatus according to any one of clauses 1-6, wherein the target detection system includes a touch sensor system, a force sensor system, one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, an optical sensor system, one or more cameras, or a combination thereof.

[0127] 8. The apparatus according to clause 7, wherein the target detection system includes an optical sensor system, and wherein the control system is further configured to control the intensity of the light emitted by the light source system at least in part based on the optical sensor data from the optical sensor system.

[0128] 9. The apparatus according to any one of clauses 1-8, wherein the target detection system includes a living body detection system.

[0129] 10. The apparatus according to clause 9, wherein the living body detection system includes a heart pulse detection system.

[0130] 11. The apparatus according to clause 10, wherein the heart pulse detection system includes a camera system, an ultrasonic pulse detection system, a light pulse detection system, a photoacoustic pulse detection system, a photoplethysmogram system, a microphone system, a ballistocardiogram sensor system, or a combination thereof.

[0131] 12. The apparatus according to any one of clauses 1-11, wherein the target detection system is configured to generate a first instance of target detection data at a first time and a second instance of target detection data at a second time, and wherein the time interval between the first time and the second time is a target detection delay period.

[0132] 13. The apparatus according to clause 12, wherein the target detection delay period is less than the pulse repetition frequency of the light source system.

[0133] 14. An apparatus comprising: a light source system; a target detection system; and a control member for: receiving target detection data from the target detection system; estimating the presence or absence of a biological target at least in part based on the target detection data; and enabling or disabling the light source system at least in part based on the estimation of the presence or absence of the biological target.

[0134] 15. The apparatus according to clause 14, wherein the light source system includes one or more lasers or laser diodes.

[0135] 16. The apparatus according to clause 14 or clause 15, wherein the light source system includes one or more light emitting diodes.

[0136] 17. The apparatus according to any one of clauses 14-16, wherein the control member includes a member for controlling the light source system to emit one or more light pulses towards the biological target and performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses.

[0137] 18. The apparatus according to clause 17 further includes an ultrasonic receiver system, wherein the control member includes a member for receiving an ultrasonic receiver signal corresponding to ultrasonic waves caused by one or more responses of the biological target to the one or more light pulses from the ultrasonic receiver system.

[0138] 19. The apparatus according to clause 18, wherein the control member includes a member for providing a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof at least partially based on the ultrasonic receiver signal.

[0139] 20. The apparatus according to any one of clauses 14 - 19, wherein the target detection system includes a touch sensor system, a force sensor system, one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, an optical sensor system, one or more cameras, or a combination thereof.

[0140] 21. A method of controlling a light source system, comprising: receiving, by a control system, target detection data from a target detection system; estimating, by the control system, the presence or absence of a biological target at least partially based on the target detection data; and enabling or disabling, by the control system and at least partially based on the estimation of the presence or absence of the biological target, the light source system.

[0141] 22. The method according to clause 21 further includes controlling, by the control system, the light source system to emit one or more light pulses towards the biological target and performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses.

[0142] 23. The method according to clause 22 further includes receiving, by the control system, an ultrasonic receiver signal corresponding to ultrasonic waves caused by one or more responses of the biological target to the one or more light pulses from the ultrasonic receiver system.

[0143] 24. The method according to clause 23 further includes providing, by the control system, a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof at least partially based on the ultrasonic receiver signal.

[0144] 25. The method according to any one of clauses 21 - 24 further includes generating, by the target detection system, a first instance of target detection data at a first time and a second instance of target detection data at a second time, and wherein the time interval between the first time and the second time is a target detection delay period.

[0145] 26. The method according to clause 25, wherein the target detection delay period is less than the pulse repetition frequency of the light source system.

[0146] 27. One or more non - transitory media having instructions stored thereon for controlling one or more devices to perform a method of controlling a light source system, the method comprising: receiving, by a control system, target detection data from a target detection system; estimating, by the control system, the presence or absence of a biological target based at least in part on the target detection data; and enabling or disabling, by the control system and at least in part based on the estimate of the presence or absence of the biological target, the light source system.

[0147] 28. The one or more non - transitory media according to clause 27, wherein the method further comprises controlling, by the control system, the light source system to emit one or more light pulses towards the biological target and performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses.

[0148] 29. The one or more non - transitory media according to clause 28, wherein the method further comprises receiving, by the control system, an ultrasonic receiver signal corresponding to ultrasonic waves caused by the one or more responses of the biological target to the one or more light pulses from an ultrasonic receiver system.

[0149] 30. The one or more non - transitory media according to clause 29, wherein the method further comprises providing, by the control system, a photoacoustic imaging function, a photoacoustic - based blood pressure estimation function, a photoacoustic - based authentication process, or a combination thereof based at least in part on the ultrasonic receiver signal.

[0150] 31. The one or more non - transitory media according to any one of clauses 27 - 30, wherein the method further comprises generating, by the target detection system, a first instance of target detection data at a first time and a second instance of target detection data at a second time, and wherein the time interval between the first time and the second time is a target detection latency period.

[0151] 32. The one or more non - transitory media according to clause 31, wherein the target detection latency period is less than the pulse repetition frequency of the light source system.

[0152] As used herein, the phrase "at least one" in a list of items refers to any combination of those items, including a single member. For example, "at least one of a, b, or c" is intended to cover a, b, c, a - b, a - c, b - c, and a - b - c

[0153] The various illustrative logical, logical blocks, modules, circuits, and algorithmic processes described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. The interchangeability of hardware and software has been generally described in terms of functionality and illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0154] The hardware and data processing apparatus for implementing or executing the various illustrative logical, logical blocks, modules, and circuits described in connection with the aspects disclosed herein can be realized using a general purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions disclosed herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, particular processes and methods may be performed by circuitry specific to a given function.

[0155] In one or more aspects, the described functionality can be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and structural equivalents thereof, or any combination thereof. Embodiments of the subject matter described in this specification can also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage medium for execution by, or to control the operation of, a data processing apparatus.

[0156] If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium (e.g., a non-transitory medium) or transmitted on the computer-readable medium. The processes of the methods or algorithms disclosed herein can be implemented as processor-executable software modules, which can be placed on a computer-readable medium. Computer-readable media includes computer storage media and communication media including any medium that can transfer a computer program from one place to another. The storage media can be any available media accessible by a computer. By way of example and not limitation, non-transitory media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer. Likewise, any connection can be properly termed a computer-readable medium. Disk and optical disks used herein include compact disk (CD), laser disk, optical disk, digital versatile disk (DVD), floppy disk, and Blu-ray disk, where disks typically reproduce data magnetically, while optical disks utilize lasers to optically reproduce data. Combinations of the above should also be included within the scope of computer-readable media. Additionally, operations of a method or algorithm can be placed as code and instruction(s) of one or any combination or set of code and instructions on a machine-readable medium and computer-readable medium, which can be incorporated into a computer program product.

[0157] Various modifications to the embodiments described in this disclosure may be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the claims, principles, and novel features disclosed herein. The term "exemplary" is used herein, if at all, only to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or better than other embodiments.

[0158] Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination within a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented separately or in any suitable sub-combination in multiple embodiments. Additionally, although features may have been described above as acting in certain combinations and even initially claimed as such, one or more features from the claimed combination can in some cases be deleted from the combination, and the claimed combination can be directed to a sub-combination or a variant of the sub-combination.

[0159] Similarly, although the operations are depicted in the drawings in a particular order, it should not be understood that such operations are required to be performed in the particular order shown or in sequential order, or that all of the illustrated operations are required to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Additionally, the separation of various system components in the above-described embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Moreover, other embodiments are within the scope of the following claims. In some cases, the acts recited in the claims can be performed in a different order and still achieve the desired result.

[0160] It should be understood that, unless the features in any particular described embodiment are explicitly identified as being incompatible with each other, or the surrounding context implies that they are mutually exclusive and not readily combinable in a complementary and / or supportive sense, the overall consideration and anticipation of the present disclosure may selectively combine the particular features of these complementary embodiments to provide one or more comprehensive but slightly different technical solutions. Accordingly, it will be further understood that the above description is given by way of example only, and modifications in details may be made within the scope of the present disclosure.

[0161] Various modifications to the embodiments described in the present disclosure may be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Accordingly, the following claims are not intended to be limited to the embodiments shown herein, but are intended to be accorded the widest scope consistent with the present disclosure, the principles disclosed herein, and novel features.

[0162] Furthermore, certain features described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments. Additionally, although features may have been described above as acting in certain combinations and even initially claimed as such, one or more features from the claimed combination may in some cases be deleted from the combination, and the claimed combination may be directed to a sub-combination or a variant of the sub-combination.

[0163] Similarly, although the operations are depicted in a particular order in the drawings, it should not be construed that such operations are required to be performed in the particular order shown or in sequential order, or that all of the operations shown are required to achieve the desired result. Additionally, the drawings may schematically depict one or more example processes in the form of a flowchart. However, other operations not depicted may be incorporated into the example processes schematically shown. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the operations shown. Further, the various operations described and shown may themselves include and commonly involve multiple sub-operations. For example, each of the operations described above may itself involve the execution of a process or algorithm. Additionally, in some embodiments, the various operations described and shown may be combined or performed in parallel. Similarly, the separation of the various system components in the above-described embodiments should not be construed as requiring such separation in all embodiments. Accordingly, other embodiments are also within the scope of the following claims. In some cases, the acts recited in the claims may be performed in a different order and still achieve the desired result.

Claims

1. A device, comprising: A light source system; A target detection system; And A control system configured to communicate with the light source system and the target detection system, the control system further configured to: Receive target detection data from the target detection system; Estimate the presence or absence of a biological target at least in part based on the target detection data; and Enable or disable the light source system at least in part based on the estimate of the presence or absence of the biological target.

2. The device according to claim 1, wherein, The light source system includes one or more lasers or laser diodes.

3. The apparatus according to claim 1, wherein, The light source system includes one or more light emitting diodes.

4. The apparatus according to claim 1, wherein The control system is further configured to control the light source system to emit one or more light pulses towards the biological target and perform one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses.

5. The apparatus according to claim 4, further comprising an ultrasonic receiver system, wherein, The control system is further configured to receive an ultrasonic receiver signal corresponding to ultrasonic waves caused by the one or more responses of the biological target to the one or more light pulses from the ultrasonic receiver system.

6. The apparatus according to claim 5, wherein, The control system is further configured to provide photoacoustic imaging functions, photoacoustic-based blood pressure estimation functions, photoacoustic-based authentication processes, or a combination thereof at least in part based on the ultrasonic receiver signal.

7. The device according to claim 1, wherein, The target detection system includes a touch sensor system, a force sensor system, one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, an optical sensor system, one or more cameras, or a combination thereof.

8. The apparatus according to claim 7, wherein, The target detection system includes an optical sensor system, and wherein the control system is further configured to control the intensity of the light emitted by the light source system at least in part based on optical sensor data from the optical sensor system.

9. The device according to claim 1, wherein, The target detection system includes a living body detection system.

10. The apparatus according to claim 9, wherein, The living body detection system includes a heart pulse detection system.

11. The device according to claim 10, wherein, The heart pulse detection system includes a camera system, an ultrasonic pulse detection system, a light pulse detection system, a photoacoustic pulse detection system, a photoplethysmogram system, a microphone system, a ballistocardiogram sensor system, or a combination thereof.

12. The device according to claim 1, wherein, The target detection system is configured to generate a first instance of target detection data at a first time and a second instance of target detection data at a second time, and wherein the time interval between the first time and the second time is a target detection delay period.

13. The device according to claim 12, wherein, The target detection delay period is less than the pulse repetition frequency of the light source system.

14. A device, comprising: A light source system; A target detection system; And A control member for: Receiving target detection data from the target detection system; Estimating the presence or absence of a biological target at least in part based on the target detection data; And Enabling or disabling the light source system at least in part based on the estimate of the presence or absence of the biological target.

15. The device according to claim 14, wherein The light source system includes one or more lasers or laser diodes.

16. The device according to claim 14, wherein, The light source system includes one or more light emitting diodes.

17. The device according to claim 14, wherein The control component includes components for controlling the light source system to emit one or more light pulses towards the biological target and performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses.

18. The apparatus according to claim 17, further comprising an ultrasonic receiver system, wherein, The control component includes components for receiving, from the ultrasonic receiver system, ultrasonic receiver signals corresponding to the ultrasound caused by the one or more responses of the biological target to the one or more light pulses.

19. The device according to claim 18, wherein, The control component includes equipment for providing a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof, at least partially based on the ultrasonic receiver signals.

20. The apparatus according to claim 14, wherein, The target detection system includes a touch sensor system, a force sensor system, one or more mechanical switches, one or more electrical switches, one or more magnetic switches, one or more magnets configured for electrical continuity, an optical sensor system, one or more cameras, or a combination thereof.

21. A method of controlling a light source system, comprising: receiving, by a control system, target detection data from a target detection system; estimating, by the control system, the presence or absence of a biological target at least partially based on the target detection data; and enabling or disabling, by the control system and at least partially based on the estimation of the presence or absence of the biological target, the light source system.

22. The method according to claim 21, further comprising controlling, by the control system, the light source system to emit one or more light pulses towards the biological target and performing one or more types of biosensing functions, biometric functions, or a combination thereof based on one or more responses of the biological target to the one or more light pulses.

23. The method according to claim 22, further comprising receiving, by the control system, from an ultrasonic receiver system, ultrasonic receiver signals corresponding to the ultrasound caused by the one or more responses of the biological target to the one or more light pulses.

24. The method according to claim 23, further comprising providing, by the control system, a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or a combination thereof, at least partially based on the ultrasonic receiver signals.

25. The method according to claim 21, further comprising generating a first instance of target detection data by the target detection system at a first time and generating a second instance of target detection data at a second time, and wherein, The time interval between the first time and the second time is a target detection delay period.

26. The method according to claim 25, wherein, The target detection delay period is less than the pulse repetition frequency of the light source system.

27. One or more non-transitory media having instructions stored thereon for controlling one or more devices to perform a method of controlling a light source system, the method comprising: receiving, by a control system, target detection data from a target detection system; estimating, by the control system, the presence or absence of a biological target at least partially based on the target detection data; and enabling or disabling, by the control system and at least partially based on the estimation of the presence or absence of the biological target, the light source system.

28. One or more non-transitory media according to claim 27, wherein, The method further includes controlling, by the control system, the light source system to emit one or more light pulses towards the biological target, and performing one or more types of biosensing functions, biometric functions, or combinations thereof based on one or more responses of the biological target to the one or more light pulses.

29. One or more non-transitory media according to claim 28, wherein, The method further includes receiving, by the control system, from the ultrasound receiver system an ultrasound receiver signal corresponding to ultrasound caused by the one or more responses of the biological target to the one or more light pulses.

30. One or more non-transitory media according to claim 29, wherein, The method further includes providing, by the control system, a photoacoustic imaging function, a photoacoustic-based blood pressure estimation function, a photoacoustic-based authentication process, or combinations thereof, at least partially based on the ultrasound receiver signal.

31. One or more non-transitory media according to claim 27, wherein, The method further includes generating, by the target detection system, a first instance of target detection data at a first time and a second instance of target detection data at a second time, and wherein a time interval between the first time and the second time is a target detection delay period.

32. One or more non-transitory media according to claim 31, wherein, The target detection delay period is less than a pulse repetition frequency of the light source system.

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