Method and application for acoustic detection of optical integrity

Abstract

The present disclosure relates to methods and applications for acoustic detection of optical integrity. The present invention relates to an acousto-optic integrity detection system architecture and method, which can be used to detect the optical integrity of an optical component by detecting discontinuities on and / or in the optical component (e.g., on the optical surface and / or within the body of the optical component). In some examples, integrity detection can be used to ensure the safety compliance of an optical system optionally including a laser. Acoustic integrity detection can utilize a transducer (e.g., a piezoelectric transducer) to transmit ultrasonic waves along the optical surface and / or through the thickness of the optical component. Discontinuities on the optical surface can interact with the transmitted wave, thereby causing attenuation, redirection, and / or reflection of at least a portion of the transmitted wave. After interacting with the discontinuity, a portion of the transmitted wave energy can be measured to determine the location, type, and / or severity of the discontinuity.

Description

Technical Field

[0001] The present application generally relates to the detection of optical integrity, and more particularly to various methods and applications for the acoustic detection of optical integrity. Background Art

[0002] Geometric optical components are currently used to perform optical operations in computing systems. Geometric optical components such as lenses, microlenses, lens arrays, etc. ("refractive optical components", "geometric optical devices", "refractive optical devices") can use non-orthogonal (e.g., greater than or less than ninety degrees) interfaces between materials with different refractive indices to bend incident light and shape light beams. One or more wavy-shaped surfaces can provide near-field and far-field optical performance for computing systems, including compliance (e.g., light / laser eye safety compliance, light / laser skin safety compliance, etc.). Compared with planar optical devices (e.g., diffractive optical devices, metasurface devices, etc.), geometric optical devices have become increasingly popular in consumer electronics due to their low cost, high efficiency, and high performance (to name just a few benefits). To ensure (i.e., substantially ensure) compliance and performance, during active illumination use (e.g., emitting light through geometric optical devices), the optical integrity of geometric optical devices in the illumination system of a computing system must be monitored, including external shape / form, internal refractive index, lamination and mounting, fluid immersion state, etc. However, due to limitations in lithographic patterning on multi-dimensional surfaces with curved / sharp transitions, and due to the thermal expansion of traditional lens array materials (e.g., glass and epoxy resins), traditional integrity detection methods (such as using resistive or capacitive safety traces) cannot be reliably applied to the wavy-shaped surfaces (e.g., convex surfaces) of geometric optical devices. Additionally, for example, direct and indirect optical / imaging detection of lens arrays may not be fully effective / compatible for all uses (e.g., due to imaging resolution), and / or may incur significant additional system costs. Summary of the Invention

[0003] This application relates to system architectures, devices, and methods for acoustic integrity detection (integrity assessment), as well as exemplary applications of system architectures, devices, and methods. For example, time-of-flight (TOF) technology or the attenuation of reflections from an array of obstacles can be used to determine the location of impurities or discontinuities in contact with or integrated into an optical surface. Acoustic integrity detection can utilize one or more transducers (such as piezoelectric transducers) to transmit ultrasonic waves along an optical surface and / or through the thickness of an optical component of an electronic device. As the wave propagates along the optical surface, one or more impurities or discontinuities in contact with or integrated into the optical surface (e.g., scratches, liquid ingress, etc.) can interact with the transmitted wave, causing attenuation, redirection, and / or reflection of at least a portion of the transmitted wave. In some examples, the portion of the transmitted wave energy after interaction with one or more impurities or discontinuities can be measured to determine the presence and / or location of one or more impurities or discontinuities on / in the optical surface of the optical component. For example, one or more transducers (e.g., acoustic transducers) coupled to an optical system (e.g., a lens array) including one or more optical components (e.g., lenses) of a device can be configured to transmit acoustic waves along the optical surface of each lens and / or through the thickness of the lens array, and can receive a portion of the wave reflected back when the acoustic wave encounters a scratch or a water droplet in or in contact with the optical surface. For example, the location of the impurity or discontinuity can be determined based on the amount of time elapsed between the transmission of the wave and the detection of the reflected wave. Acoustic integrity detection can be used in place of other integrity detection techniques (such as the application of resistive and / or capacitive security traces) or in combination with other integrity detection techniques. In some examples, the acoustic integrity detection techniques described herein can be used on the wavy profile surface of a lens in a lens array of a device, which may not be suitable for capacitive or resistive security traces due to the three-dimensional shape of the lens surface. In some examples, the acoustic touch sensing techniques described herein can be used on the surface of a display coupled to a lens array. In some examples, an acoustic integrity detection system can be configured to control the operability of one or more light emitters of an illumination system such that light emission is disabled when an impurity or discontinuity is detected in one or more lenses of the lens array. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figures 1A to 1E An exemplary electronic device that may include an acousto-optic integrity detection system is shown in accordance with an example of the present disclosure.

[0005] Figure 2 An exemplary block diagram of an electronic device including an optical integrity detection system is shown in accordance with an example of the present disclosure.

[0006] Figure 3A An exemplary method for acoustic detection of optical integrity for an optical system is shown in accordance with an example of the present disclosure.

[0007] Figure 3B Illustrates an exemplary process for operating a light emitter based on the optical integrity of an optical system according to an example of the present disclosure.

[0008] Figure 4 Illustrates an exemplary configuration of an acousto-optic integrity detection circuit according to an example of the present disclosure.

[0009] Figures 5A to 5B Illustrates exemplary perspective views of a material stack of an electronic device and a simplified single sheet of the material stack according to an example of the present disclosure, respectively.

[0010] Figures 6A to 6B Illustrates an exemplary configuration of a lens array for mounting one or more acoustic transducers into a material stack of an electronic device according to an example of the present disclosure.

[0011] Figure 7 Illustrates an exemplary detailed side cross-sectional view of one or more acoustic transducers coupled between a display and a lens array according to an example of the present disclosure.

[0012] Figures 8A to 8C Illustrates an exemplary detailed side cross-sectional view of an exemplary configuration of one or more ultrasonic sensing layers forming one or more acoustic transducers coupled to a lens array according to an example of the present disclosure.

[0013] Figures 9A to 9F Illustrates an exemplary signal diagram of an acoustic detection demonstrating the optical integrity of an optical system according to an example of the present disclosure. Detailed Description

[0014] Cross-reference to Related Applications

[0015] This application claims the benefit of U.S. Provisional Application No. 63 / 209,935, filed Jun. 11, 2021, and U.S. Patent Application No. 17 / 664,832, filed May 24, 2022, the entire contents of both of which are incorporated herein by reference for all purposes.

[0016] In the following description of various examples, reference will be made to the accompanying drawings that form a part of the following description and in which specific examples that may be implemented are shown by way of illustration. It should be understood that other examples may be used and structural changes may be made without departing from the scope of the various examples.

[0017] The present disclosure relates to system architectures, devices, and methods for acoustic integrity detection (e.g., optical integrity detection) and exemplary applications of system architectures, devices, and methods. For example, the attenuation of reflections from an array of obstacles can be used to evaluate the optical integrity of the surface (e.g., a curved or wavy profile surface) of an optical component (e.g., a lens) of an optical system (e.g., a microlens array). Acoustic integrity detection can utilize one or more transducers (such as piezoelectric transducers) to transmit ultrasonic waves along an optical surface and / or through the thickness of an electronic device. As the wave propagates along the optical surface, one or more impurities (e.g., cracks, scratches, water ingress, etc.) present in or in contact with the optical surface can interact with the transmitted wave, causing attenuation, redirection, and / or reflection of at least a portion of the transmitted wave. The portion of the transmitted wave energy after interaction with one or more impurities can be measured to determine the optical integrity of the optical surface of the optical component within the device. For example, one or more transducers (e.g., acoustic transducers) coupled to the optical surface of an optical component within a device can be configured to transmit acoustic waves along the optical surface and / or through the thickness of the optical component and can receive a portion of the wave reflected back when the acoustic wave encounters an impurity on and / or in the optical surface. The presence of an impurity can be determined, for example, based on an evaluation (i.e., measurement) of one or more characteristics (such as differences in amplitude or period) of the transmitted wave and the reflected wave. For example, one or more characteristics of the reflected wave can be compared to a baseline acoustic response captured by the transducer (e.g., during an optical test in a factory to confirm the optical safety compliance of a known good optical device). In some examples, the location of an impurity can be determined (e.g., using time-of-flight techniques) based, for example, in part on the amount of time elapsed between the transmission of the wave and the detection of the reflected wave. Acoustic integrity detection can be used in place of other integrity detection techniques (such as the application of resistive and / or capacitive safety traces) or in combination with other integrity detection techniques. In some examples, the acoustic integrity detection techniques described herein can be used on the wavy profile surface of an optical component, which may not be suitable for capacitive or resistive touch sensing due to limitations in lithographic patterns on three-dimensional surfaces with sharp transitions. In some examples, the acoustic integrity detection techniques described herein can be used on the glass or epoxy surface of a lens array. In some examples, an acoustic integrity detection system can be configured to control the light emission of one or more light emitters from an illumination system within a device.

[0018] Figures 1A to 1E An example of a system with a touch screen and an optical component is shown, and the optical component can include an acoustic sensor for detecting impurities in and / or on the optical surface of the optical component of the system. Figure 1AAn exemplary mobile phone 136 is shown, which includes a touch screen 124 and may include an acoustic and optical integrity detection system ("acoustic and optical integrity detection system", "acoustic integrity detection system", "acoustic integrity assessment system") according to an example of the present disclosure. Figure 1B An exemplary digital media player 140 is shown, which includes a touch screen 126 and may include an acoustic integrity detection system according to an example of the present disclosure. Figure 1C An exemplary personal computer 144 is shown, which includes a touch screen 128 and a touchpad 146 and may include an acoustic integrity detection system according to an example of the present disclosure. Figure 1D An exemplary tablet computing device 148 is shown, which includes a touch screen 130 and may include an acoustic integrity detection system according to an example of the present disclosure. Figure 1E An exemplary wearable device 150 (e.g., a watch) is shown, which includes a touch screen 152 and may include an acoustic integrity detection system according to an example of the present disclosure. The wearable device 150 may be coupled to a user via a strap 154 or any other suitable fastener. It should be understood that Figures 1A to 1E The exemplary devices shown are provided as examples, and other types of devices may include an acoustic integrity detection system for detecting the presence of impurities on and / or in the optical surfaces of the optical components of the device. Additionally, although Figures 1A to 1E the devices shown include touch screens, in some examples, the device may also have a non-touch-sensitive display.

[0019] An acoustic sensor may be incorporated into the above system to increase the acoustic integrity detection ability of the optical surface of the optical components of the system. For example, the acoustic sensor may allow the evaluation of impurities on the optical surfaces of one or more lenses in a lens array during the manufacturing stage (e.g., before the final encapsulation of a device including a lens array). In some examples, the above system may include an illumination system that includes one or more light emitters, which may be lasers, light-emitting diodes, vertical-cavity surface-emitting lasers (VSCELs), etc. Thus, for example, the acoustic sensor may allow the evaluation of the optical integrity of the optical components of the optical system of the device before the actuation of one or more emitters to ensure a sufficient amount of optical integrity, thereby contributing to the effective light emission from one or more emitters. As another example, in some examples, the optical surface of the optical component may be enhanced with an acoustic sensor to provide an optical integrity detection ability for detecting water ingress in a humid environment or under conditions where the device may get wet (e.g., exercise, swimming, rain, handwashing, etc.).

[0020] Figure 2An exemplary block diagram of an electronic device including an acousto-optic integrity system according to an example of the present disclosure is shown. In some examples, a lens (within a lens array) 202 of device 200 (which may correspond to devices 136, 140, 144, 148, and 150 described above), i.e., an optical component of the optical system described above, may be coupled to one or more acoustic transducers 204. In some examples, transducer 204 may be a piezoelectric transducer that may vibrate upon application of an electrical signal when acting as a transmitter and generate an electrical signal based on detected vibrations when acting as a receiver. In some examples, transducer 204 may be formed of a transparent piezoelectric ceramic material (e.g., ZnO or AlN) or a transparent piezoelectric polymer material (e.g., PVDF). Similarly, transducer 204 may generate electrical energy as an output when vibrating. In some examples, transducer 204 may be bonded to lens 202 by an adhesive (e.g., a thin layer of rigid epoxy). In some examples, transducer 204 may be disposed on an optical surface by processes such as deposition, lithography, etc. In some examples, transducer 204 may be bonded to a surface using a conductive or non-conductive bonding material. When electrical energy is applied to transducer 204, the electrical energy may cause the transducer to vibrate, and may also cause the surface material in contact with the transducer to vibrate, and the vibrations of the molecules of the surface material may propagate as acoustic waves through the surface material. In some examples, the vibrations of transducer 204 may be used to generate ultrasonic waves at a selected frequency within a wide frequency range (e.g., 20 kHz–800 kHz, 20 kHz - 1 MHz, or other suitable frequency ranges) in the medium of the optical surface of lens 202, and the optical surface of the lens may be glass, plastic (e.g., epoxy resin), etc. It should be understood that other frequencies outside the above exemplary ranges may be used while remaining within the scope of the present disclosure.

[0021] In some examples, the lens 202 (e.g., within a lens array) may also be partially or fully optically coupled to one or more light emitters 220 (e.g., lasers). In some examples, the light emitter 220 is configured to emit light, where the light may propagate through the lens 202, through the transducer 204, and through the touchscreen 208. In some examples, the transducer 204 may also be partially or fully disposed on a portion of the touchscreen 208 (or coupled to a portion of the touchscreen), which may be coupled / integrated into the housing 218. For example, the touchscreen 208 (e.g., a capacitive touchscreen) may include a glass panel (cover glass), and the display area of the touchscreen may be surrounded by a non-display area (e.g., a black border area around the periphery of the display area of the touchscreen). In some examples, the transducer 204 may be partially or fully disposed in the black mask area of the glass panel of the touchscreen 208 (e.g., on the back surface of the glass panel behind the black mask), such that the transducer is invisible (or only partially visible) to the user. In some examples, the transducer 204 may be partially or fully coupled to the display area of the touchscreen 208, such that the transducer 204 is coupled between the touchscreen 208 and the lens 202. In such examples, the transducer 204 may be made of a transparent or partially transparent material (e.g., ZnO, AlN) to allow all or a majority of the light to pass through, e.g., the display area.

[0022] Device 200 may also include an acoustic-optic integrity detection circuit 206. The acoustic-optic integrity detection circuit may include a circuit (e.g., a transmitting circuit) for driving an electrical signal to excite the vibration of the transducer 204, and a circuit (e.g., a receiving circuit) for sensing the electrical signal output by the transducer when the transducer is excited by the received acoustic energy. In some examples, the timing operation of the acoustic integrity detection circuit 206 may optionally be provided by a separate acoustic-optic integrity detection controller 210, which may control the timing of the operation of the acoustic integrity detection circuit 206. In some examples, the integrity detection controller 210 may be coupled between the acoustic integrity detection circuit 206 and the host processor 214. In some examples, the controller function may be integrated with the acoustic integrity detection circuit 206 (e.g., on a single integrated circuit). The output data from the acoustic integrity detection circuit 206 may be output to the host processor 214 for further processing to determine the location, type, and / or severity of impurities on and / or in the lens 202 or display (e.g., touch screen 208) of the device, as will be described in more detail below. In some examples, the processing for determining the location, type, and / or severity of surface impurities may be performed by the acoustic integrity detection circuit 206, the controller 210, or a separate sub-processor (not shown) of the device 200. In some examples, the acoustic detection circuit 206, the controller 210, or a separate sub-processor (not shown) may use the determination of the presence of surface impurities (i.e., the determination based on location, type, and / or severity) to control the light emission (from the light emitter 220).

[0023] In addition to the acoustic integrity detection circuit 206, the device may also include an additional touch circuit 212 and optionally a touch controller (not shown) that may be coupled to the touch screen 208. In some examples including a touch controller, the touch controller may be disposed between the touch circuit 212 and the host processor 214. For example, the touch circuit 212 may be a capacitive or resistive touch sensing circuit and may be used to detect the contact and / or hovering of an object (e.g., a finger, a stylus, etc.) in contact with and / or approaching the touch screen 208, particularly in the display area of the touch screen. Thus, the device 200 may include multiple types of detection circuits (e.g., the touch circuit 212 and the acoustic integrity detection circuit 206) for detecting objects (and their locations) in different areas of the device while detecting impurities in the optical components (lens 202) within the device, as will be described in more detail below. Although described herein as including a touch screen, it should be understood that the touch circuit 212 may be omitted and the touch screen 208 may be replaced with other non-touch-sensitive displays.

[0024] The host processor 214 may receive acoustic output or other touch output (e.g., capacitive output) and perform actions based on the touch output. The host processor 214 may also be connected to the program storage device 216 and the touch screen 208. For example, the host processor 214 may communicate with the touch screen 208 to generate images on the touch screen 208, such as images of a user interface (UI), and may use the touch sensing circuitry 212 to detect touches on or near the touch screen 208, such as touch inputs to the displayed UI. The touch inputs may be used by computer programs stored in the program storage device 216 to perform actions, which may include but are not limited to: moving objects such as a cursor or pointer, scrolling or panning, adjusting control settings, opening files or documents, viewing menus, making selections, executing instructions, operating peripheral devices connected to the host device, answering a telephone call, placing a telephone call, terminating a telephone call, changing the volume or audio settings, storing information related to telephone communications (such as addresses, frequently dialed numbers, incoming calls, missed calls), logging in to a computer or computer network, allowing authorized individuals access to restricted areas of a computer or computer network, loading a user profile associated with the arrangement of a user's preferred computer desktop, allowing access to web content, launching a specific program, encrypting or decrypting messages, etc. The host processor 214 may also perform additional functions that may not be related to touch processing, such as the operation of the acoustic integrity detection circuitry 206 (and in some examples, the acoustic integrity detection controller 210) to detect impurities (such as scratches or water ingress) on or near the lens 202 and / or the operation of the light emitter 220.

[0025] Note that one or more of the functions described herein may be performed by instructions stored in a memory and executed by the touch circuitry 212 and / or the acoustic integrity detection circuitry 206 (or their respective controllers), or stored in the program memory 216 and executed by the firmware of the host processor 214. The firmware may also be stored and / or conveyed within any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device such as a computer-based system, a system including a processor, or other systems that can obtain instructions from and execute the instructions of the instruction execution system, apparatus, or device. In the context of this disclosure, a "non-transitory computer-readable storage medium" can be any medium (excluding signals) that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. Non-transitory computer-readable media memory can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, a portable computer disk (magnetic), random access memory (RAM) (magnetic), read-only memory (ROM) (magnetic), erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc (such as a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW), or flash memory (such as a compact flash card, secure digital card), a USB storage device, a memory stick, etc.

[0026] The firmware may also be propagated within any transmission medium for use by or in connection with an instruction execution system, apparatus, or device such as a computer-based system, a system including a processor, or other systems that can obtain instructions from and execute the instructions of the instruction execution system, apparatus, or device. In the context of this document, a "transmission medium" can be any medium that can convey, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. Transmission-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, or infrared wired or wireless propagation media.

[0027] It should be understood that the device 200 is not limited to Figure 2 the components and configurations shown, but may include other components or additional components in a variety of configurations according to various examples. Additionally, the components of the device 200 may be included within a single device, or may be distributed among multiple devices. Further, it should be understood that the connections between the components are exemplary, and according to the embodiments, different unidirectional or bidirectional connections may be included between the components, regardless of Figure 2 the arrows shown in the configurations.

[0028] Figure 3AAn exemplary method 300 for acoustic detection of optical integrity of an optical system according to an example of the present disclosure is shown. At 302, for example, acoustic energy may be transmitted (e.g., by one or more transducers 204) in the form of ultrasonic waves along or through an optical surface of an optical component of a device. In some examples, the wave may propagate as a compressional wave, a shear horizontal wave, a Rayleigh wave, a Lamb wave, a Love wave, a Stoneley wave, or a surface acoustic wave. Based on the characteristics of the surface material and the mode of energy transmission from the transducer to the optical surface of the optical component, there may also be other propagation modes for transmitting the acoustic energy. In some examples, the optical surface may be formed of glass or epoxy resin (e.g., lens 202), or the surface may be formed of glass or sapphire crystal (e.g., touch screen 208). The transmitted energy may propagate along the surface until it reaches a discontinuity / impurity in the surface, which may cause a portion of the energy to be reflected. In some examples, the discontinuity or impurity may be an irregularity in the surface shape (e.g., a groove or pattern etched into the surface). In some examples, the discontinuity may be a reflective material coupled to the surface (e.g., disposed on the surface). In some examples, water in contact with the surface (e.g., water ingress) may also be a discontinuity. In some examples, a discontinuity may occur at the edge (i.e., end point) of the surface material (e.g., when the ultrasonic wave propagates to the edge of the surface opposite the transducer). In some examples, the lamination of an optical component (e.g., a lens array) of an optical system with a display (e.g., the display of a touch screen) may also be a discontinuity. When the transmitted energy reaches one of the above-described discontinuities, some of the energy may be reflected, and a portion of the reflected energy may be directed to one or more transducers 204.

[0029] At 304, the returned acoustic energy can be received and converted into an electrical signal by one or more transducers 204. At 306, the acoustic sensing system can determine whether one or more impurities or discontinuities are present on and / or in the surface of the optical component, and can further detect the location, type, and / or severity of one or more impurities based on the received acoustic energy. In some examples, the distance of the impurity from the transmission source (e.g., transducer 204) can be determined based on the time of flight between the emission and reception of the reflected energy and the propagation rate of the ultrasonic wave through the material. In some examples, a baseline reflected energy (known from a fully functional and continuous optical surface (i.e., no abnormal / unexpected discontinuities or impurities)) can be compared with the measured value of the reflected energy. As an example, the baseline reflected energy can be determined based on the simulation of the ideal integrity curve of a particular optical surface and component and / or based on the stored integrity curve obtained during the testing of a particular optical surface and component (e.g., stored in a memory). The timing of the measured deviation of the reflected energy from the baseline can be related to the location of the impurity. In some examples, the amplitudes along multiple arcs of the transmitted and received waves can be recorded and processed to reconstruct an amplitude image of each location. Although method 300 generally refers to the reflected wave received by the transducer of the transmitted wave as described above, in some examples, the transmitter function and the receiver function can be separated such that the emission of acoustic energy at 302 and the reception of acoustic energy at 304 may not occur at the same transducer (e.g., one transducer is configured to transmit and one transducer is configured to receive). Exemplary device configurations and measurement timing examples that can be used to implement method 300 will be described in more detail below.

[0030] In some examples, the acousto-optic integrity detection can determine the operability of one or more light emitters 220 such that the emission of light from one or more light emitters 220 depends on the integrity of the optical component. For example, the acousto-optic integrity detection can include a criterion (e.g., indicating optical integrity) of the received acoustic energy that must be met in order for light to be emitted from one or more light emitters. One or more criteria can be referred to herein as optical integrity criteria or integrity criteria. Figure 3B An exemplary process 320 for operating a light emitter based on the optical integrity of an optical system according to an example of the present disclosure is shown. Process 300 can include emitting and receiving acoustic energy as in 302 and 304, as described above with respect to Figure 3AAs described above. At 322, the acousto-optic integrity detection system may use the received acoustic energy and one or more integrity criteria to evaluate optical integrity. In some examples, the detected optical integrity may be represented according to one or more characteristics of the reflected energy (such as quantitative values of amplitude, time of flight, period, etc.), as described above. As described above, these quantitative values may allow the system to determine the location, type, and / or severity of the detected impurities, such that, for example, the optical component may be marked and the detected impurities may be noted (e.g., replaced, fixed, etc.). Additionally or alternatively, for Figure 3B the exemplary process 320 shown in, the detected optical integrity may simply be represented according to whether impurities are detected (e.g., a positive detection or a negative detection). Thus, at 322, the optical integrity detection system may check whether an unexpected discontinuity / impurity is detected and determine whether to enable light emission based on whether an unexpected discontinuity / impurity is detected. It can be understood that this simplified evaluation step may enable a determination of whether light emission can be performed more quickly (compared to the time taken to detect the location, type, and / or severity of the impurities). As shown, if one or more criteria are met (i.e., no impurities are detected), the light emitter 220 is enabled and allowed to emit light (324). Alternatively, if one or more criteria are not met (i.e., one or more impurities are detected), the light emitter 220 is disabled and not allowed to emit light (326).

[0031] It should be understood that Figures 3A to 3B the exemplary processes 300 and 320 shown in may be performed multiple times or several times according to desire or need. For example, the process 320 may be performed each time light is emitted from one or more light emitters 220. Additionally or alternatively, in some examples, the integrity detection process 300 may be performed more than once (e.g., two or three times) to reduce the occurrence of false positives (i.e., false detection of impurities) and / or false negatives (i.e., false detection of no impurities).

[0032] Figure 4 An exemplary configuration of an acousto-optic integrity detection circuit 400 according to an example of the present disclosure is shown. The acoustic integrity detection circuit 400 may include acoustic integrity detection circuits 402-404 and 408-420 (which may correspond to the acoustic integrity detection circuit 206 described above) and control logic 422 (which may correspond to the acoustic integrity detection controller 210 described above). In some examples, the acoustic integrity detection circuit 400 may also optionally include a transducer 406 (which may correspond to the transducer 204 described above). Although Figure 4Although not shown in the figure, in some examples, the acousto-optic integrity detection circuit 400 may optionally further include an optical system, which includes optical components (which may correspond to the lens 202), and an optical emission circuit (which may correspond to the optical transmitter 220 and may include a control circuit for operating the optical transmitter based on the optical integrity detection).

[0033] In some examples, the transmitter 402 may generate an electrical signal for exciting the movement of one or more of the plurality of transducers 406. In some examples, the transmitted signal may be a differential signal, and in some examples, the transmitted signal may be a single-ended signal. In some examples, the transmitter 402 may be a simple buffer, and the transmitted signal may be a pulse (or a burst of pulses at a specific frequency). In some examples, the transmitter 402 may include a digital-to-analog converter (DAC) 402A and an optional filter 402B, which is optionally used to smooth the quantized output of the DAC 402A. In some examples, the characteristics of the transducer itself may provide filtering characteristics, and the filter 402B may be omitted. The DAC 402A may be used to generate any transmit waveform. In some examples, any waveform may pre-distort the transmit signal to equalize the channel. In some examples, the characteristics of each channel may be measured and stored, such as the characteristics of the surface material coupled to the transducer 406, the discontinuities in the surface material, and the reflection characteristics of the optical surface of the optical components of the device. In some examples, the channel characteristics may be measured as a manufacturing step (or a factory calibration step), while in other examples, the characteristics may be measured as a periodic calibration step (i.e., once a month, once a year, etc., depending on the speed at which the channel characteristics are expected to change). In some examples, the channel characteristics may be converted into the transfer function of the channel, and the inverse of the channel transfer function may be used to configure any transmit waveform such that the return signal is equalized (e.g., although the transmitted waveform has a seemingly arbitrary waveform, the return signal may be detected as a pulse or a burst of pulses). In some examples, a single differential pulse may be used as the transmit waveform. For example, a bipolar square pulse (where the voltage applied to the transducer may be both positive and negative) may be used as the transmit waveform, and the bipolar square pulse may be implemented using a single-ended or differential implementation.

[0034] A pair of demultiplexers 404 (e.g., in a differential implementation) can be used to selectively couple the transmitter 402 to one of the transducers 406, which can be the active transducer for a particular measurement step in a cycle. In some examples, the demultiplexer 404 can have a ground connection, and the unselected demultiplexer outputs can be shorted, open, or grounded. As described above, when acoustic energy causes motion in the transducer, the transducer 406 can also generate an output electrical signal. A pair of multiplexers 408 (e.g., in a differential implementation) can be used to select the transducer 406 for coupling to the programmable gain amplifier 410, which is configured to amplify the received signal. In some examples, the same transducer 406 can be coupled to the transmitter 402 through the demultiplexer 404 during the drive mode and to the programmable gain amplifier 410 through the multiplexer 408 during the receive mode. Thus, a single transducer 406 can be used to transmit acoustic energy as well as receive acoustic energy. In some examples, the first transducer can be coupled to the transmitter 402 through the demultiplexer 404, and the second transducer can be coupled to the programmable gain amplifier 410 through the multiplexer 408. For example, the transmit transducer and the receive transducer can be discrete piezoelectric elements, where the transmit transducer can be designed to be driven by a higher voltage (or current) to generate sufficient motion in the transducer 406 to generate acoustic waves in the surface of the device (e.g., device 200 described above), and the receive transducer can be designed to receive the reflected energy with a smaller amplitude. In such an architecture, the transmit-side circuitry (e.g., 402 and 404) can optionally be implemented on a high-voltage circuit, while the receive-side circuitry (e.g., 408 - 420) can optionally be implemented on a separate low-voltage circuit. In some examples, the multiplexer 408 can also be implemented on the high-voltage circuit to properly isolate the remaining receive-side circuitry (e.g., 410 - 420) during the transmission operation of the transmit-side circuitry. Additionally or alternatively, in some examples, the transmit circuit can include an energy recovery architecture that can be used to recover some of the energy required to charge and discharge the transducer. In some examples, the programmable gain amplifier output can be coupled to the gain and offset correction circuit 412. It should be understood that for a single-ended implementation, a single demultiplexer 404 and a single multiplexer 408 can be used, and the inputs to the transmitter 402, the programmable gain amplifier 410, and the gain and offset correction circuit 412 can also be single-ended. However, compared to a single-ended implementation, a differential implementation can provide improved noise suppression.

[0035] In some examples, an acoustic touch sensing circuit can be used in a system that includes a plurality of transmit transducers and one receive transducer. In such examples, demultiplexer 404 may be unnecessary and can be omitted from the acoustic touch sensing circuit. In some examples, an acoustic touch sensing circuit can be used in a system that includes a plurality of receive transducers and one transmit transducer. In such examples, multiplexer 408 may be unnecessary and can be omitted from the acoustic touch sensing circuit.

[0036] In some examples, the output of gain and offset correction circuit 412 can optionally be coupled to one or more analog processing circuits. In some examples, the output of gain and offset correction circuit 412 can be coupled to demodulation circuit 414, which is configured to demodulate the received signal (e.g., by I / Q demodulation). In some examples, the output of gain and offset correction circuit 412 can be coupled to envelope detection circuit 415, which is configured to perform envelope detection on the received signal. In some examples, the output of gain and offset correction circuit 412 can be filtered at filter 416. In some examples, these blocks can be placed in a different order. In some examples, the processing of these analog processing circuits can be performed in the digital domain.

[0037] The received signal, whether the original signal or the signal processed by one or more of demodulation circuit 414, envelope detection circuit 415, or filter 416, can be passed to analog-to-digital converter (ADC) 418 to be converted into a digital signal. In some examples, input / output (I / O) circuit 420 can be used to transfer the received data for processing. In some examples, the output of I / O circuit 420 can be transferred to the host processor of the device, or to an auxiliary processor (sub-processor) separate from the host processor. For example, as shown, the output of I / O circuit 420 can be coupled to processor system-on-chip (SoC) 430, which can include one or more processors. In some examples, processor SoC 430 can include host processor 432 (e.g., an active mode processor) and auxiliary processor 434 (e.g., a low-power processor). In some examples, some digital signal processing (e.g., by acoustic touch sensing circuit 400) can be performed before transferring the data to other processors in the system (e.g., processor SoC 430). Control circuit 422 can be used to control the timing and operation of acoustic integrity detection circuits 402 - 420. In some examples, I / O circuit is used not only for data transfer to processor SoC 430 (e.g., host processor 432), but also for writing to control registers and / or downloading firmware from processor SoC 430.

[0038] As described herein, for example, an optical emission circuit can include a laser driver ( Figure 4(not shown in the figure), the laser driver is configured to drive one or more optical emitters. In some examples, the optical emission circuit may receive an interrupt signal or other control signal to prevent optical emission from an optical system including a laser when an optical impurity is detected (e.g., to ensure safety compliance of the optical system including the laser). In some examples, the control for enabling or disabling the optical emission circuit may be performed by the processor SoC 430 using the output of the I / O circuit 420 (and thus using the output of the transducer 406). In some examples, the control may be provided directly by the I / O circuit 420 without using the processor SoC 430. As discussed herein, the optical emission circuit may receive an indication (or indications) of a detected discontinuity at, on, and / or near a lens (e.g., corresponding to the lens 202) (e.g., via one or more reflections received by one or more of the transducers 406). The control of the optical emission circuit may generate an interrupt signal (e.g., a one-bit message or flag, such as a logic high) received by a laser driver that drives one or more optical emitters, which may cause the one or more optical emitters to abort optical emission (e.g., as shown at 326 in Figure 3B ). Additionally or alternatively, when one or more of the transducers 406 do not detect a discontinuity and a go signal (e.g., a single-bit message or flag, such as a logic low) is received, the optical emission circuit may allow the laser driver / optical emitter to emit light without an interrupt signal (e.g., as shown at 324 in Figure 3B ).

[0039] It should be understood that Figure 4 the configuration is not limited to Figure 4 the components and configurations of Figure 4 but may include other or additional components in various configurations according to various examples. For example, although not explicitly shown for simplicity, Figure 4 the configuration may include an optical emission circuit that may include, for example, a laser driver configured to drive one or more optical emitters 220 and receive an interrupt signal to prevent optical emission (e.g., when an optical impurity is detected), as discussed above. Additionally, some or all of the components 402 - 404 and 408 - 420 may be included in a single circuit or may be divided among multiple circuits while remaining within the scope of the examples of the present disclosure.

[0040] As described herein, various acoustic sensing techniques can be used to detect one or more impurities on, in, or near an optical surface of an optical component, and thereby evaluate the optical integrity of the optical component of an optical system. In some examples, the optical system can be a microlens array (MLA) having one or more lenses, and can interact with an illumination system including one or more light emitters, as disclosed above. One or more acoustic transducers can be coupled to the MLA to evaluate the optical integrity of one or more lenses, and based on this optical integrity, enable or disable one or more light emitters (e.g., operate as a fail-safe for the illumination system), as described below.

[0041] Figures 5A to 5B Exemplary perspective views of a material stack of an electronic device and a simplified single sheet of the material stack according to an example of the present disclosure are shown, respectively. Figure 5A A perspective view of a material stack 520 including an illumination system within an electronic device is shown. As referred to above Figure 2 when described, the electronic device can include a touch screen 208 or other screen (e.g., a non-touch display screen) disposed above one or more lenses 202. As Figure 5A shown, the material stack (also referred to herein as a "stack") can include a display screen that includes a cover glass 521 laminated above a display 522 (e.g., a display layer where display circuits such as light-emitting diodes, organic light-emitting diodes, etc. can be disposed). As shown, the stack 520 can also include an MLA 523 coupled (e.g., laminated or deposited) below the display 522, and finally one or more transducers 524 and / or acoustic integrity detection circuits 506 coupled to the MLA 523 using an adhesive 519. As described above, the transducers 524 and / or acoustic integrity detection circuits 506 can be configured to generate acoustic waves / ultrasonic waves (e.g., shear horizontal waves) and receive the reflected acoustic waves. As will be described below, the acoustic waves can propagate through the MLA 523 to detect impurities or discontinuities that may be present in or on one or more lenses of the MLA 523.

[0042] As described above, the electronic device can include an illumination system that utilizes the MLA 523. As Figure 5A shown, the illumination system can include a collimator 525 and one or more light emitters 527. Although not shown, a driver can be configured to drive one or more light emitters 527, and the collimator 525 can collimate the light beams emitted from one or more light emitters 527. The driver can be coupled to, for example Figure 2communicates with the acousto-optic integrity detection circuit 206 and / or the acousto-optic integrity detection controller 210 shown. As described herein, one or more light emitters 527 (e.g., which may be lasers) may be configured to selectively emit light 529. As shown by way of example, the light 529 emitted from the one or more light emitters 527 may be directed through a collimator 525, which may include, for example, a display wiring hole, such that the light 529 may be refracted by the MLA 523 through the display 522 to achieve a high-power user-facing illumination function (e.g., far-field illumination for facial recognition capabilities), among other possibilities. Impurities or discontinuities (such as scratches, water ingress, or delaminated connections (e.g., between the MLA and the display)) present in or on the MLA 523 may impede or prevent the light 529 (and thus the optical power) from being effectively illuminated through the display 522. As will be discussed in more detail later, the ultrasonic transducer 524 and the acoustic integrity detection circuit 506 may provide an effective and reliable integrated detection method for evaluating the optical integrity of the MLA 523, so as to enable higher optical power to be output from the one or more emitters 527 and thus improve device performance.

[0043] Figure 5B is shown in a simplified configuration Figure 5A A perspective view of a single sheet 520A of the material stack is shown. As described above, an electronic device having a touch screen or other non-touch display screen may include a cover glass 521, a display 522, and an MLA 523, which are arranged in a material stack structure in a recess of the electronic device. As Figure 5B shown, Figure 5B a single sheet 520A of the material stack 520 may protrude a lens 530 of one or more lenses of the MLA 523. As an example, the MLA 523 may be an array of lenses of any suitable number and arrangement (e.g., 12×30 lenses, 15×35 lenses, 10×24 lenses, etc.). As shown, the lens 530 may be coupled to the display 522 via an adhesive layer 528 (e.g., an epoxy layer, a pressure-sensitive adhesive, etc.). As described herein, an adhesive layer (e.g., the adhesive layer 528 or a portion of the adhesive layer 519) may couple the transducer 524 and / or the acoustic integrity detection circuit 506 ( Figure 5B not shown in) to the display 522 and / or the MLA 523 (and thus to the lens 530). As described in more detail below, the transmission of sound waves and the reception of reflected sound waves may allow for the evaluation of the optical surfaces of one or more lenses (e.g., the lens 530) of the MLA 523 for any impurities or discontinuities.

[0044] Figures 6A to 6BAn exemplary configuration of a lens array 623 for mounting one or more acoustic transducers 624 and / or an acoustic integrity detection circuit 606 into a material stack of an electronic device according to an example of the present disclosure is shown. As discussed above with reference to Figures 5A to 5B As discussed above, one or more transducers 624 and / or an acoustic integrity detection circuit 606 can be coupled to the MLA 623 such that ultrasonic waves generated by one or more transducers 624 can propagate through one or more lenses of the MLA 623, and the reflected ultrasonic waves can be received by one or more transducers 624. As discussed herein, a variety of mounting configurations can be used to effectively couple the transducer 624 and / or the acoustic integrity detection circuit 606 to the MLA 623. Figures 6A to 6B Also shown is a cover glass 621 (e.g., corresponding to cover glass 521), a portion of the housing 618 (e.g., corresponding to a portion of the housing 518), a collimator 625 (e.g., corresponding to collimator 525), and light 629 (e.g., corresponding to light 529) emitted by a light emitter (not shown), and details thereof are not repeated for brevity.

[0045] Figure 6A A first exemplary configuration for mounting the transducer 624 and / or the acoustic integrity detection circuit 606 to the MLA 623 is shown. As Figure 6A shown, the transducer 624 and / or the acoustic integrity detection circuit 606 optionally overlap a portion of the bottom surface of the MLA 623. In some examples, the transducer 624 is coupled between the MLA 623 and the display 622, and one or more transducers can be implemented in one or more ultrasonic sensing layers 631. In some such examples, the acoustic integrity detection circuit 606 (e.g., corresponding to the acoustic integrity detection circuit 206 and / or the acoustic integrity detection circuit 400) can be coupled to the MLA 623 using an adhesive 619 (e.g., corresponding to the adhesive 519). As shown, the transducer can be implemented in one or more ultrasonic sensing layers 631 adhered to the display 622 via an adhesive layer 628 (e.g., corresponding to Figure 5B the adhesive layer 528 in Figure 7 discussed in more detail. For example, the acoustic integrity detection circuit can be configured to generate sound waves, detect reflected sound waves, and / or process reflected sound waves. In some examples, the transducer 624 and / or the acoustic integrity detection circuit 606 can be mounted on one side of the MLA 623 (e.g., the right side of the MLA 623 (as Figure 6Aas shown), or mounted on the left side of the MLA 623). Alternatively, in some examples, the transducer 624 and / or the acoustic integrity detection circuit 606 can be mounted on both sides of the MLA 623 as needed or desired (e.g., the right and left sides on the lower side of the MLA 623). For example, multiple transducers can improve the detection and / or localization of impurities or discontinuities in one or more lenses of the MLA 623.

[0046] Figure 6B FIG. shows a second exemplary configuration for mounting the transducer 624 and / or the acoustic integrity detection circuit 606 to the MLA 623. As Figure 6B shown, the transducer 624 and / or the acoustic integrity detection circuit 606 is optionally adjacent to a portion of one side of the MLA 623 such that the transducer 624 and / or the acoustic integrity detection circuit 606 is coupled between the MLA 623 and the display 622. In some examples, the transducer 624 and / or the acoustic integrity detection circuit 606 can be coupled to the MLA 623 and the display 622 using an adhesive 619. In some examples, the transducer can be implemented in one or more ultrasonic sensing layers 631 that are adhered to the display 622 via an adhesive layer 628 (e.g., corresponding to Figure 5B the adhesive layer 528 in Figure 7 discussed in more detail. For example, the acoustic integrity detection circuit can be configured to generate sound waves, detect the reflected waves, and / or process the reflected sound waves. In some examples, the transducer 624 and / or the acoustic integrity detection circuit 606 can be mounted on one side of the MLA 623 (e.g., the right side of the MLA 623), as Figure 6B shown, or mounted on the left side of the MLA 623. Alternatively, in some examples, one or more transducers 624 and / or the acoustic integrity detection circuit 606 can be mounted on both sides of the MLA 623 as needed or desired (e.g., the right and left sides). For example, multiple transducers can improve the detection and / or localization of impurities or discontinuities in one or more lenses of the MLA 623.

[0047] It should be understood that, as described above, either or both of the above transducer and / or acoustic integrity detection circuit mounting structures can achieve effective transmission of sound waves and reception of the reflected sound waves for integrity detection. However, there may be cases where the transducer functions are separated, and one configuration may be superior to the other, such as for ease of integration and / or reducing manufacturing costs.

[0048] As described herein, a sound transducer and / or an acoustic integrity detection circuit can be coupled to a display and / or a lens array within a material stack of an electronic device. In some examples, the sound transducer can be coupled between a display and / or a lens array within the material stack of the electronic device. The sound transducer can be configured to generate and transmit acoustic waves through one or more lenses of the lens array such that any impurities and defects present in or on the one or more lenses will be captured by the reflected waves received by the sound transducer (e.g., via a change in wave characteristics). Figure 7 FIG. shows an exemplary detailed side cross-sectional view of an acoustic integrity detection component 760 (including one or more transducers and an acoustic integrity detection circuit) coupled between a display 722 and a lens array 723 according to an example of the present disclosure. As described herein, by way of example, the material layers and support circuits forming the one or more sound transducers and / or the acoustic integrity detection circuit can be provided in a variety of configurations.

[0049] As Figure 7 shown in the detailed cross-sectional view of, by way of example, the acoustic integrity detection component 760 (e.g., also referred to herein as an optical integrity sensor or an integrity sensing system) can include one or more material sub-layers arranged in a stacked manner. In some examples, as Figure 7 shown, the acoustic integrity detection component 760 can include a substrate (e.g., a glass substrate) on which one or more transducers can be provided. As Figure 7 shown in the detailed view of, the corresponding sub-layer forming the one or more transducers 724 can be represented by, for example, one or more ultrasonic sensing layers 731. As described in more detail with reference to Figures 8A to 8C the one or more ultrasonic sensing layers 731 can include discrete sub-layers of electrodes and piezoelectric materials, e.g., each transducer is formed by a segment of piezoelectric material and two electrodes. As described above, various configurations of the one or more ultrasonic sensing layers 731 can be provided to form the one or more transducers. In some examples, the ultrasonic sensing layer can be provided only on top of the substrate 734 (e.g., a glass substrate), as shown by the upper ultrasonic sensing layer 731A. In some examples, the ultrasonic sensing layer can be provided only on the bottom side of the substrate 734, as shown by the lower ultrasonic sensing layer 731B. In some examples, the ultrasonic sensing layer can be provided on both the top and bottom of the substrate 734, as shown by the ultrasonic sensing layer 731 (e.g., the upper ultrasonic sensing layer 731A and the lower ultrasonic sensing layer 731B).

[0050] In a first configuration, according to some examples, an upper ultrasonic sensing layer 731A disposed on top of a substrate 734 allows the use of acoustic waves to inspect / evaluate the integrity of the bottom surface of the display 722 (e.g., adjacent to the upper ultrasonic sensing layer 731A), which may be particularly useful for detecting discontinuities such as delamination (e.g., delamination of the substrate 734 from the display 722 due to adhesive failure of the epoxy resin layer 733A). In a second configuration, according to some examples, a lower ultrasonic sensing layer 731B disposed on the bottom of the substrate 734 allows the use of acoustic waves to inspect the integrity of the top surface of the MLA 723 and the surfaces of the lenses 730A - 730C of the MLA 723, which is particularly useful for detecting discontinuities such as lens scratches, ingress of liquid in contact with one or more lens surfaces, and delamination (e.g., delamination of the top surface of the MLA 723 from the substrate 734 due to adhesive failure of the epoxy resin layer 733B). In a third configuration, according to some examples, ultrasonic sensing layers 731 disposed on the top and bottom of the substrate 734 allow the use of acoustic waves to inspect the integrity of both the bottom surface of the display 722 and the top surface of the MLA 723, as well as the respective integrity of the lenses 730A - 730C of the MLA 723. Thus, the number and arrangement of the ultrasonic sensing layers 731 can be selected according to one of the above configurations to inspect the optical integrity of various optical surfaces within the material stack of the electronic device based on the above considerations.

[0051] In some examples, such as in the Figures 5A to 6B material stack shown, the substrate 734 is not provided. In some such examples, the substrate 734 can be removed so that a single ultrasonic sensing layer can be formed directly on top of the MLA 723 (e.g., on the flat surface of the MLA 723, as similarly shown by the lower ultrasonic sensing layer 731B). The single ultrasonic sensing layer can then be directly coupled to the display 722 (via an adhesive layer, such as an epoxy resin layer 733A) such that the ultrasonic sensing layer is disposed between the display 722 and the MLA 723 (e.g., in direct contact with the display and the MLA). In this way, acoustic waves can be used to inspect the integrity of the bottom surface of the display 722 and the respective surfaces of the lenses 730A - 730C of the MLA 723 in order to detect abnormal discontinuities such as lens scratches, liquid ingress, and delamination (e.g., delamination of the top surface of the MLA 723 from the bottom surface of the display 722).

[0052] As Figure 7As shown, the acoustic integrity detection component 760 can be coupled to the display and the MLA using the adhesive epoxy resin layers 733A and 733B, which can be disposed along the bottom surface of the display 722 and along the top surface of the MLA 723, respectively. Thus, one or more transducers (e.g., formed by one or more ultrasonic sensing layers 731) can be coupled to the display 722 and / or one or more transducers can be coupled to the MLA 723. It should be understood that in some examples, depending on the configuration of the ultrasonic sensing layer, the epoxy resin layers 733A and 733B can directly contact one or more surfaces of the substrate 734. It should also be understood that the adhesive epoxy resin layers 733A and 733B can include additional or alternative materials for coupling the transducers to the display 722 and / or the MLA 723. Additionally, as shown, the ultrasonic sensing layer 731 can be electrically connected to the acoustic integrity detection circuit 706 (e.g., corresponding to Figure 2 in 206) using, for example, a suitable number of conductive vias 735 (e.g., metal vias). It should be understood that Figure 7 the number of conductive vias 735 shown is merely an example, and a greater or lesser number (e.g., two, three, seven, ten, etc.) of conductive vias 735 can be provided. It should also be understood that although the vias 735 are shown, any suitable electrical connection (e.g., electrically wound wire, wire bonding, or cable) can also be used. The acoustic integrity detection circuit 706 can be coupled to a flexible circuit (e.g., flexible printed circuit board) 732, which can be electrically connected to the acousto-optic integrity detection controller (e.g., corresponding to Figure 2 in 210) or other processing circuit. In some examples, one or more lenses of the microlens array (e.g., lenses 730A - 730C) can be formed of a suitable material such as glass or plastic, which can be selected based on the application and other constraints such as temperature.

[0053] As described above, the acoustic transducer 724 can include one or more ultrasonic sensing layers (e.g., 731) that form the transducer, from which ultrasonic waves can be transmitted to detect / check the integrity of one or more surfaces within the material stack of the electronic device associated with the optical system. As described above, one or more ultrasonic sensing layers can include additional sublayers, such as including an electrode layer and / or a piezoelectric layer. Figures 8A to 8C An exemplary detailed side cross-sectional view of an exemplary configuration of one or more ultrasonic sensing layers forming one or more acoustic transducers coupled to the lens array 823 according to an example of the present disclosure is shown.

[0054] As described above with reference to Figure 7 In some examples, the material stack of the electronic device can include a substrate (e.g., glass substrate) 834. Also as described above, one or more ultrasonic sensing layers 831 (e.g., Figure 7The 731) can be disposed on one or both sides of a glass substrate (e.g., 734). In some examples, the first ultrasonic sensing layer and the second ultrasonic sensing layer are disposed on the top and bottom sides of the substrate 834, as Figure 8A shown. For example, Figure 8A shows an upper ultrasonic sensing layer 831A disposed on top of the substrate 834 and a lower ultrasonic sensing layer 831B disposed below the substrate 834. In some examples, the ultrasonic sensing layer 831 is disposed on one side. For example, Figures 8B to 8C shows an ultrasonic sensing layer 831 disposed on top of the substrate 834. As Figures 8A to 8C shown, the substrate 834 can be coupled to the top (e.g., flat) surface of the MLA 823 via an epoxy adhesive layer 833, as described above. Although not shown in Figures 8A to 8C , an additional adhesive layer can be disposed on top of the upper ultrasonic sensing layer 831A, or the ultrasonic sensing layer 831 can be disposed on top of the substrate to couple one or more transducers to the display.

[0055] As described above and as Figures 8A to 8C shown in the detailed view of, one or more ultrasonic sensing layers (e.g., 831, 831A, 831B) can each include a plurality of electrode layers and one or more piezoelectric layers. Various configurations of the electrode layers and the piezoelectric layers can be used to form one or more transducers. Figure 8A shows an exemplary detailed cross-sectional view of a first configuration of a plurality of electrode layers 836A - 836D, 837A - 837B and one or more piezoelectric layers 838A - 838D according to an example of the present disclosure.

[0056] As Figure 8A shown, the first ultrasonic sensing layer 831A and the second ultrasonic sensing layer 831B can be disposed on the top and bottom surfaces of the substrate 834 (e.g., corresponding to Figure 7 the ultrasonic sensing layer 731) in. In some examples, in Figure 8AIn the first configuration shown in the detailed view, a plurality of electrode layers and a plurality of piezoelectric layers may be provided within the first ultrasonic sensing layer 831A and the second ultrasonic sensing layer 831B. For example, referring to the first ultrasonic sensing layer 831A, a first electrode layer 836A, a second electrode layer 836B, and a third electrode layer 837A may be provided, where the first electrode layer 836A, the second electrode layer 836B, and the third electrode layer 837A are optically transparent or semi-transparent electrodes (e.g., composed of ITO, metal mesh, silver nanowires, etc.). In this first configuration, the first electrode layer 836A may be configured as a receiver electrode (Rx electrode), the second electrode 836B may be configured as a transmitter electrode (Tx electrode), and the third electrode layer 837A may be configured as a ground electrode. Additionally, a first piezoelectric layer 838A and a second piezoelectric layer 838B (e.g., constructed of ZnO or AlN) may be provided, where the first piezoelectric layer 838A is disposed between the ground electrode layer 837A and the RX electrode (e.g., the first electrode layer 836A), and the second piezoelectric layer 838B is disposed between the ground electrode layer 837A and the Tx electrode (e.g., the second electrode layer 836B). The first piezoelectric layer 838A, the first electrode layer 836A, and the ground electrode layer 837A may form a first receiver transducer 824A configured to receive reflected acoustic waves; the second piezoelectric layer 838B, the second electrode layer 836B, and the ground electrode layer 837A may form a transmitter transducer 824B configured to transmit acoustic waves. As described herein, in some examples, the first electrode layer 836A and the second electrode layer 836B may include a plurality of electrodes such that transducer arrays 824A and / or transducer arrays 824B may be formed.

[0057] As Figure 8AAs shown, the second ultrasonic sensing layer 831B may be disposed between the substrate 834 and the MLA 823. In some examples, as shown, the second ultrasonic sensing layer 831B may include an array of transducers 824C and 824D disposed across the bottom surface of the substrate 834. As shown, the fourth electrode layer 836C, the fifth electrode layer 836D, and the sixth electrode layer 837B may be optically transparent or translucent electrodes (e.g., ITO, metal mesh, etc.). As shown, the fourth electrode layer 836C may be pixelated such that a plurality of patterned first electrodes (e.g., Rx electrodes) are provided, including a first receiver electrode pixel 836C-a, a second receiver electrode pixel 836C-b, and a third receiver electrode pixel 836C-c. Similarly, as shown, the fifth electrode layer 836D may be pixelated such that a plurality of patterned second electrodes (e.g., Tx electrodes) are provided, including a first transmitter electrode pixel 836D-a, a second transmitter electrode pixel 836D-b, and a third transmitter electrode pixel 836D-c. As shown, the second ultrasonic sensing layer 831B may further include a third piezoelectric layer 838C and a fourth piezoelectric layer 838D, which are respectively disposed between the ground electrode layer 837B and the fourth and fifth electrode layers 836C-836D. In this example, the plurality of patterned first electrodes 836C-a-836C-c may be configured to share the third piezoelectric layer 838C, and the plurality of patterned second electrodes 836D-a-836D-c may be configured to share the fourth piezoelectric layer 838D, so as to generate a first transducer array 824C and a second transducer array 824D, wherein a receiver-configured transducer of the first transducer array and a transmitter-configured transducer of the second transducer array are formed above the corresponding lenses of the MLA 823. For example, the receiver electrode pixels 836C-a–836C-c of the fourth electrode layer 836C, the third piezoelectric layer 838C, and the ground electrode layer 837B may form an array of receiver transducers 824C, each receiver transducer being configured to receive reflected acoustic waves; and the transmitter electrode pixels 836D-a–836D-c of the fifth electrode layer 836D, the fourth piezoelectric layer 838D, and the ground electrode layer 837B may form an array of transmitter transducers 824D, each transmitter transducer being configured to transmit acoustic waves. In this way, each lens 830A-830C of the MLA 823 may be provided with a corresponding pair of receiver-configured transducers and transmitter-configured transducers, which are configured to individually detect the integrity of the corresponding lens by transmitting ultrasonic waves and receiving one or more corresponding reflections from the corresponding lens.

[0058] Continuing to refer to the first configuration of the electrodes and piezoelectric layers described above and Figure 8A shown, acoustic waves transmitted from the first ultrasonic sensing layer 831A may be used to detect the display (e.g., corresponding to Figure 7The optical surface of the display 722) therein. The emitter transducer 824B formed by the second electrode 836B and the second piezoelectric layer 838B (and the shared ground electrode layer 837A) can transmit acoustic waves upward to the display (not shown) and generate detectable reflections from the bottom surface of the display. For example, the receiver transducer 824A formed by the first electrode 836A and the first piezoelectric layer 838A (and the ground electrode layer 837A) can receive the energy from the reflected wave. As described herein, the presence of impurities or abnormal discontinuities (e.g., due to delamination) along the bottom surface of the display can cause changes in the transmitted acoustic waves, and such changes can be detected in the reflected acoustic waves received at the receiving transducer 824A (e.g., based on changes in the amplitude, time of flight, period, etc. of the received signal compared to the baseline signal). Thus, when the optical system involves the bottom surface of the display (e.g., Figure 7 the display 722 therein, through which light from the light emitter passes), the integrity of the optical system can be evaluated by transmitting ultrasonic waves and receiving one or more corresponding reflections.

[0059] Similarly, the optical surfaces of the exemplary lenses 830A - 830C of the MLA 823 can be probed using acoustic waves transmitted from the second ultrasonic sensing layer 831B. For example, an array of emitter transducers 824D formed by a plurality of patterned second electrodes 836D-a–836D-c and the fourth piezoelectric layer 838D (and the ground electrode layer 837B) can each transmit acoustic waves through the substrate 834 and generate detectable reflections from each lens of the MLA 823. An array of receiver transducers 824C formed by a plurality of patterned first electrodes 836C-a–836C-c and the third piezoelectric layer 838C (and the ground electrode layer 837B) can receive the energy from the reflected wave. The presence of impurities or abnormal discontinuities in any of the lenses 830A - 830C of the MLA 823 can cause changes in the transmitted acoustic waves, and such changes can be detected in the reflected acoustic waves received at the array of receiving transducers 824C (e.g., based on changes in the amplitude, time of flight, period, etc. of the received signal compared to the baseline signal). Additionally, the presence of impurities or abnormal discontinuities on the top surface of the MLA 823 (e.g., due to delamination) can cause changes in the transmitted acoustic waves, and such changes can be detected in the reflected acoustic waves. Thus, the integrity of the lenses (e.g., lenses 830A - 830C) and the top surface of the MLA 823 can be evaluated by transmitting one or more ultrasonic waves and receiving one or more corresponding reflections.

[0060] It should be understood that Figure 8AThe configuration of the multiple electrode layers and the multiple piezoelectric layers within the exemplary material stack can be changed as needed or desired. For example, the first ultrasonic sensing layer 831A can alternatively be arranged as an array disposed across the top surface of the substrate 834 and be configured similarly to the second ultrasonic sensing layer 831B. As another example, the second ultrasonic sensing layer 831B can alternatively be implemented without pixelated electrodes and be configured similarly to the first ultrasonic sensing layer 831A. As another example, the exemplary configurations of the first ultrasonic sensing layer 831A and the second ultrasonic sensing layer 831B can be switched such that the first ultrasonic sensing layer 831A is a pixelated array while the second ultrasonic sensing layer 831B is not a pixelated array. In some examples, the piezoelectric material and / or the ground electrode can also be divided into multiple segments, with each transducer having discrete segments. Additionally or alternatively, the transducers configured as transmitters and receivers can use separate ground electrodes instead of sharing a common ground electrode. Additionally or alternatively, the transducer functions of the transmitter and receiver pairs can be combined into one transducer (e.g., as described with reference to Figure 8C .

[0061] Figure 8B FIG. shows an exemplary detailed cross-sectional view of a second configuration of multiple electrode layers 836A - 836B, 837 and one or more piezoelectric layers 838A - 838B according to an example of the present disclosure. As Figure 8B shown, an ultrasonic sensing layer 831 can be provided on the top surface of the substrate 834 (e.g., as shown by the upper ultrasonic sensing layer 731A in Figure 7 previously).

[0062] In some examples, at Figure 8BIn the second configuration shown in the detailed view, the ultrasonic sensing layer 831 may be provided as an array disposed across the top surface of the substrate 834. The first electrode layer 836A, the second electrode layer 836B, and the third electrode layer 837 may be optically transparent or translucent electrodes (e.g., ITO, metal mesh, etc.). The first electrode layer 836A may be pixelated to form a plurality of patterned first electrodes (e.g., Rx electrodes), including a first receiver electrode pixel 836A-a, a second receiver electrode pixel 836A-b, and a third receiver electrode pixel 836A-c. Similarly, the second electrode layer 836B may be pixelated to form a plurality of patterned second electrodes (e.g., Tx electrodes), including a first transmitter electrode pixel 836B-a, a second transmitter electrode pixel 836B-b, and a third transmitter electrode pixel 836B-c. The third electrode layer 837 may be configured as a ground electrode layer. As shown, the ultrasonic sensing layer 831 may also include a first piezoelectric layer 838A and a second piezoelectric layer 838B, which are disposed on opposite sides of the ground electrode layer 837. In this example, the plurality of patterned first electrodes 836A-a - 836A-c, the first piezoelectric layer 838A, and the ground electrode form a transducer in a receiver configuration. The plurality of patterned second electrodes 836B-a - 836B-c, the second piezoelectric layer 838B, and the ground electrode form a transducer in a transmitter configuration. As shown, the first transducer array 824A and the second transducer array 824B may be formed by one receiver-configuration transducer and one transmitter-configuration transducer formed above the respective lenses of the MLA 823. In a manner similar to that referenced Figure 8A As described, the corresponding receiver transducer and transmitter transducer pairs may be configured to individually detect the optical integrity of the respective lenses (through the substrate 834) by transmitting ultrasonic waves and receiving one or more corresponding reflections from the respective lenses.

[0063] It should be understood that Figure 8B the configuration of the multiple electrode layers and multiple piezoelectric layers within the exemplary material stack may be changed as needed or desired. For example, the ultrasonic sensing layer 831 may not be pixelated and may be configured similarly to Figure 8A the first ultrasonic sensing layer 831A shown. As another example, the ultrasonic sensing layer 831 may alternatively be disposed on the bottom surface of the substrate 834 (e.g., as shown by the lower ultrasonic sensing layer 731B in Figure 7 ). In some examples, the piezoelectric material and / or the ground electrode may also be divided into multiple segments, with each transducer having a discrete segment. Additionally or alternatively, the transducers configured as transmitters and receivers may use separate ground electrodes instead of sharing a common ground electrode.

[0064] As referenced above Figures 8A to 8BAs described, one or more ultrasonic sensing layers (e.g., ultrasonic sensing layers 831A - 831B, 831) may include a plurality of piezoelectric layers (e.g., a first piezoelectric layer 838A, a second piezoelectric layer 838B, a third piezoelectric layer 838C, etc.), where some transducers are configured for separate transmitter or receiver functions. Additionally or alternatively, in some examples, one or more ultrasonic sensing layers may include a single piezoelectric layer (as described below) to form a transducer that can be configured to perform both transmitter and receiver functions. Figure 8C Exemplary detailed cross - sectional view showing a third configuration of a plurality of electrode layers 836A - 836B and one or more piezoelectric layers 838 according to an example of the present disclosure. As Figure 8C shown, the ultrasonic sensing layer 831 may be disposed on the top surface of the substrate 834 (e.g., as shown by the upper ultrasonic sensing layer 731A in Figure 7 previously).

[0065] In some examples, in the third configuration shown in the detailed view of Figure 8C , the ultrasonic sensing layer 831 may be disposed across the top surface of the substrate 834 and may include two electrode layers and one piezoelectric layer. For example, a first electrode layer 836A and a second electrode layer 836B may be provided, where the first electrode layer 836A and the second electrode layer 836B are optically transparent or semi - transparent electrodes. The first electrode layer 836A and / or the second electrode layer may be pixelated. As shown, Figure 8C it includes a first electrode 836A - a, a second electrode 836A - b, a third electrode 836A - c, a fourth electrode 836B - a, a fifth electrode 836B - b, and a sixth electrode 836B - c. Additionally, a single piezoelectric layer 838 may be provided, where the single piezoelectric layer 838 is disposed between the first electrode layer 836A and the second electrode layer 836B. In this example, the plurality of patterned first electrodes 836A - a - 836A - c, the plurality of patterned second electrodes 836B - a - 836B - c, and the piezoelectric layer 838 may form an array of transducers 824, each transducer formed above a corresponding lens of the MLA 823, where each transducer may operate in a transmit configuration to generate ultrasonic waves and then in a receive configuration to receive ultrasonic wave reflections. Transducers configured in this way can be used to individually detect the optical integrity of the corresponding lenses by transmitting ultrasonic waves and receiving one or more corresponding reflections (e.g., through the substrate 834) from the corresponding lenses.

[0066] It should be understood that Figure 8C the configuration of the plurality of electrode layers and the plurality of piezoelectric layers within the exemplary material stack may be changed as needed or desired. For example, although the two electrode layers in Figure 8Care all shown as pixelated, but one of the electrode layers (e.g., the ground layer) may not be pixelated. In some examples, the ultrasonic sensing layer 831 may not be pixelated and is configured similarly to Figure 8A the first ultrasonic sensing layer 831A shown, but incorporates the transmitter and receiver functions of the transducer implemented with a single piezoelectric layer 838. As another example, the ultrasonic sensing layer 831 may alternatively be disposed on the bottom surface of the substrate 834 (e.g., as shown by the lower ultrasonic sensing layer 731B in Figure 7 ). As another example, the ultrasonic sensing layer 831 having a single piezoelectric layer 838 may be disposed on both the top and bottom surfaces of the substrate 834 (e.g., as shown by the ultrasonic sensing layer 731 in Figure 7 ). In some examples, the piezoelectric material may also be divided into multiple segments, with each transducer having a discrete segment.

[0067] As described above, in the Figure 8A and Figure 8B first and second configurations, one or more sub-layers may include two piezoelectric layers within the respective ultrasonic sensing layer, where the first piezoelectric layer (e.g., 838A) may form the receiver transducer and the second piezoelectric layer (e.g., 838B) may form the transmitter transducer. The separation of the transmitter piezoelectric layer and the receiver piezoelectric layer can reduce crosstalk because the excitation / vibration of the transmitter piezoelectric layer (e.g., the second piezoelectric layer 836B) (which may be at a high voltage (e.g., 1V)) can be separate and thus independent of the generation of vibrations by the receiver piezoelectric layer (e.g., the first piezoelectric layer 836A). Specifically, when transmitting sound waves over a short distance (e.g., when the total thickness of the layer between the ultrasonic sensing layer and the layer of interest (such as the lens of the MLA 823) is relatively small), separating the transmitter transducer and the receiver transducer may be beneficial because the crosstalk between the transmitted sound wave and the reflected sound wave may be relatively low and / or negligible, thereby allowing the detection of changes in the reflected wave. In some examples, the short distance may refer to a distance less than or equal to three times the wavelength of the ultrasonic energy in the intermediate layer between the transducers, and the discontinuity points where the reflection of interest is generated (e.g., at the interface of the laminated layers, at the surface of the MLA 823, etc.). In some examples, the wavelength of the ultrasonic energy in the intermediate layer can be calculated based on the frequency of the transmitted ultrasonic energy and the speed of the ultrasonic energy in the intermediate layer. Having the transmitter and receiver functions in a shared transducer may have relatively low functional reliability over a short distance because the shared functional transducer receives a portion of the energy emitted by the transmitter as crosstalk between the transmitter transducer and the receiver transducer (e.g., due to ringing caused by excitation masking reflections).

[0068] In some examples, the substrate 834 may be omitted such that the ultrasonic sensing layer may be disposed directly on top of the MLA 823 (e.g., on the flat surface of the MLA 823, as similarly shown for the lower ultrasonic sensing layer 731B in Figure 7 ).

[0069] As discussed herein, one or more transducers coupled between a display and an optical system (e.g., a lens array) may be configured to generate ultrasonic waves that propagate to one or more optical components (e.g., lenses) of the optical system and receive the reflected ultrasonic waves from one or more optical surfaces (e.g., lens surfaces) of the optical components for evaluating the optical integrity of the optical system. As described above, in the case where the transmitted ultrasonic waves encounter one or more impurities or discontinuities, one or more characteristics of the reflected ultrasonic waves may change (compared to the transmitted ultrasonic waves). One or more impurities or discontinuities may be any impurity or discontinuity present on, in, and / or near the optical surface of the corresponding optical component. One or more characteristics of the reflected ultrasonic waves may be analyzed and processed (e.g., by Figure 2 the acoustic integrity detection circuit 206 and / or the controller 210 in

[0070] ) to determine the location, type, and / or severity of one or more impurities or discontinuities.

[0071] Figures 9A to 9F An exemplary signal diagram showing the acoustic detection of the optical integrity of a demonstration optical system according to an example of the present disclosure is shown. It should be noted that Figures 9A to 9F the exemplary signal diagram shown represents what is representative of being generated by Figures 8A to 8CThe reflected signals (e.g., analog signals) received by one or more transducers in one or more exemplary configurations. It should be understood that the graph titles of the signal graphs (e.g., "Top Sensor, RX Layer", "Top Sensor, TX Layer", "Bottom Sensor, RX Layer", "Bottom Sensor, TX Layer") may correspond to a configuration including an ultrasonic sensing layer and three electrode layers (e.g., 836A, 836B, and 837A), each ultrasonic sensing layer having two piezoelectric layers (e.g., Figure 8A 838A and 838B in

[0072] Figures 9A to 9F Exemplary signal graphs 940A - 940L of impurities at the analog MLA detected according to the disclosed acoustic integrity detection method are shown. As Figures 9A to 9F shown, as indicated by legend 941, the signal graphs show a baseline signal 942 (e.g., corresponding to the signal of the measurement of the acoustic energy at each transducer in the absence of impurities / unexpected discontinuities) and a reflected signal 943 (e.g., corresponding to the signal of the acoustic energy at each transducer in the presence of impurities / unexpected discontinuities), represented, for example, as voltage (in microvolts [μV]) versus time (in nanoseconds [ns]). In some examples, the reflected signal 943 can be compared with the baseline signal 942, and the deviation of one or more features of the reflected signal from the baseline signal can indicate a defect. It should be understood that for Figures 9A to 9F all the corresponding signal graphs shown, the corresponding baseline signals 942 of the upper ultrasonic sensing layer and the lower ultrasonic sensing layer can be the same.

[0073] In some examples, the correlation between the reflected signal 943 and the baseline signal 942 can be calculated, and when the correlation drops below a threshold, impurities can be detected. In some examples, the magnitude squared of the difference between the reflected signal 943 and the baseline signal 942 (e.g., an energy metric) can be calculated, and when the calculated value exceeds a threshold, impurities can be detected. In some examples, defects can be detected based on the appearance of new peaks in the reflected signal 943 that do not appear in the baseline signal 942. It should be understood that the above are exemplary comparison means between the reflected signal 943 and the baseline signal 942, but other variations of features (e.g., changes in oscillation frequency, phase, amplitude, etc.) can also be used.

[0074] Figures 9A to 9BShows a simulation of delaminated impurities. Generally, delaminated impurities can be detected at any location within the stack, including but not limited to, between the cover glass 721 and the display 722, inside the display 722, at the adhesive layer 733A at the bottom of the display, between the adhesive layer 733A at the bottom of the display and the ultrasonic transducer in the ultrasonic sensing layer 731 (above the substrate 734), between the ultrasonic transducer in the ultrasonic sensing layer 731 (below the substrate 734) and the adhesive layer 733B above the MLA 723, and between the adhesive layer 733B and the MLA 723. Figures 9A to 9B Shows a simulation of delamination of the MLA 723 at the epoxy resin layer 733B. Signal diagrams 940A and 940B may correspond to transducers in the upper ultrasonic sensing layer ("top sensors"), and signal diagrams 940C and 940D may correspond to transducers in the lower ultrasonic sensing layer ("bottom sensors").

[0075] As Figures 9A to 9B shown, the bottom transducer in the transmit configuration (e.g., corresponding to transducer 824D), as indicated by the maximum signal amplitude that appears in signal diagram 940D during the initial period 944A, and as the distance of the corresponding transducer from the excitation transducer (e.g., transducer 824D) increases, the amplitudes at the corresponding times in signal diagrams 940C, 940B, and 940A decrease. For some of the initial periods 944A - 944D in signal diagrams 940A - 940D, the baseline signal 942 and the reflected signal 943 may be the same or substantially the same, such that the two signals continuously overlap or substantially overlap during the initial periods 944A - 944D (e.g., for each of the signal diagrams 940A - 940D, which may have different durations). Then, after the initial period 944, the relative peaks (e.g., peak 945) and valleys (e.g., valley 954) of the reflected signal 943 begin to deviate from the peaks and valleys of the baseline signal 942. The reflected signal (or reflected signals from multiple transducers) from one of the transducers can be used to identify the presence of delaminated impurities (e.g., based on a threshold decrease in correlation with the baseline or an increase in the squared magnitude of waveform deviation).

[0076] In some examples, the presence of delaminated impurities at a specified location within a stack can be determined. For example, the location of the impurities can be determined based on the amount of time between the transmission of an acoustic wave and the detection of a deviation in the reflected signal by a transducer pair (the time after the initial period 944). For example, in signal diagram 940A, additional oscillations that do not appear in the baseline signal can be detected in the reflected signal starting from valley 954. This time (sometimes referred to as the time of flight (TOF)) can be used, along with the propagation speed of the acoustic wave in the surface medium (e.g., glass or epoxy), which can be a known quantity or can be measured empirically, to determine the distance between the transducer and the impurity. Thus, the location of the delaminated impurity can be located so that corrective action can be taken when applicable (e.g., repair the delamination damage, discard the unit, disable or compensate for the operation of the optical system). It should be noted that in some examples, multiple different TOF measurements can be determined for the multiple signal diagrams 940A - 940D shown in Figures 9A to 9B . In such examples, averaging (or some other mathematical operation) can be performed to generate, for example, the approximate location of the delaminated impurity within the stack.

[0077] In some examples, the reflected signals can be compared within a specific time window defined based on the propagation speed of the acoustic energy / ultrasonic energy and the distance between a specific location and the transducer configured in the transmit configuration and / or the distance between the specific location and the transducer configured in the receive configuration and / or the distance between the specific location and the transducer configured in the receive configuration, to detect a deviation from the baseline signal within the specific window, thereby detecting delamination at the corresponding location within the stack. It should be understood that different time windows can be examined in a similar manner to detect delamination in other regions of the stack.

[0078] Figures 9C to 9D Exemplary signal diagrams 940E - 940H showing simulated damaged microlens array impurities detected according to the disclosed acoustic integrity detection method are shown. Figures 9E to 9F Exemplary signal diagrams 940I - 940L showing simulated water ingress impurities detected according to the disclosed acoustic integrity detection method are shown. In a manner similar to that described with respect to Figures 9A to 9B , the bottom sensor in the transmit configuration can generate an excitation signal, and signal diagrams 940E - 940L show the reflected signals 943 and the baseline signals 942 of the top and bottom sensors in the receive and transmit configurations.

[0079] For the initial periods 944E - 944L in signal diagrams 940E - 940L (which can have different durations), the baseline signal 942 and the reflected signal 943 can be the same or substantially the same, and then the reflected signal 943 can deviate from the baseline signal 942. This observed change between the reflected signal 943 and the baseline 942 can be used in a manner similar to that described with respect to Figures 9A to 9BDetect the presence and / or location of defects in a similar manner. For example, the correlation or magnitude squared of the difference between the reflected signal and the baseline signal (e.g., energy metric) can be used to detect deviations from the baseline. A threshold deviation from the baseline typically indicates the presence of a defect.

[0080] In some examples, different defects can be distinguished based on the amount and / or manner of the deviation. For example, as Figures 9E to 9F shown, the water ingress impurity simulation shows that, for example, the correlation between the baseline and the reflected signal is higher compared to the correlation with lens impurities and / or delamination impurities. Similarly, as Figures 9C to 9D shown, the MLA impurity simulation shows that, for example, the correlation between the baseline and the reflected signal is higher compared to the correlation with delamination impurities. Thus, one or more different thresholds can be determined empirically and used to classify impurities into different categories. Additionally or alternatively, the time-of-flight difference can be used to distinguish different defects based on their position in the stack. For example, windows of interest corresponding to different layers in the stack can be defined and analyzed to detect whether a deviation occurs within the window of interest for delamination at a corresponding position in the stack, lens defects at the position of the MLA, or water ingress at the position between the MLA and the light emitter.

[0081] Although Figures 9A to 9F shows a simulation in which the bottom sensor is excited, it should be understood that another sensor (e.g., the top sensor) can be alternatively excited. In some examples, the detection of different defects / impurities can be based on the excitation of different sensors. For example, the bottom sensor can be excited to detect delamination in the lower half of the stack, and the top sensor can be excited to detect delamination in the upper half of the stack (e.g., above the substrate).

[0082] In some examples, as discussed above, the location of the impurity can be determined. In some examples, damage to one or more specific lenses, delamination of the layers on one or more specific lenses, and / or water ingress on one or more specific lenses can be detected based on the location. In some such examples, these local impurities can be repaired. In some such examples, these local impurities can be used to disable some of the light emitters with an optical path passing through one of these local impurities, while other light emitters can continue to operate or remain enabled. In some examples, all light emitters can be disabled regardless of the location of the defect.

[0083] As referred to Figure 2 above, by a transducer (e.g., Figure 2The frequency of the ultrasonic waves generated in (e.g., 204) can be high (e.g., greater than 100 kHz) and can be selected from a frequency range such as from 20 kHz to 800 kHz (or another frequency range). Operating the transducer at a high frequency can help ensure that one or more impurities or discontinuities that may be present in the corresponding optical component or on the corresponding optical component or in other layers in the stack can be reliably detected and evaluated at a short distance (e.g., the material thickness is less than or equal to 300 μm) and independently of other potential factors such as temperature variations. Alternatively, for example, the use of a low frequency can result in a reduced resolution of the reflection (compared to high-frequency excitation), which generally enables the detection of impurities or discontinuities but may make it more difficult to reliably detect and evaluate one or more characteristics of the reflection (and thus less likely to determine the impurity location, type, and / or severity).

[0084] As described with respect to Figure 3B the detection of impurities can determine whether light can be emitted within the light illumination system (e.g., from the light emitter 527 in FIG. 5). As discussed above, in some examples, detecting an impurity can prevent light emission ( Figure 3B e.g., 335 in), while not detecting an impurity can enable light to be emitted ( Figure 3B e.g., 330 in). As described, this determination can be made regardless of the details of the impurity (i.e., location, type, and severity). However, in some examples, even when an impurity is detected, light emission can still be enabled, which can be based on details of the optical integrity, as outlined above. For example, detecting one or more severe impurities (such as a broken or missing lens) or delamination of the lens array from the display may indicate that light emission from one or more light emitters will be optically obstructed beyond an acceptable level. However, detecting one or more less severe impurities (such as a minor scratch or almost negligible water ingress) may indicate that light emission is still possible without significantly hindering the operation of the device. Thus, the acoustic integrity detection method can be configured to enable light emission from one or more light emitters based on determining that the corresponding impurity determined by its severity (and / or location and / or type) does not impair or significantly affect the operation of the device.

[0085] For example, referring back to Figure 2, the host processor 214 may be configured to receive and process signal data corresponding to one or more changes in the reflected ultrasonic waves received by one or more ultrasonic transducers (e.g., full reflection data may be transmitted from the transducer and / or the acousto-optic integrity detection circuit 206 to the host processor). Thus, the host processor 214 may be configured to determine the location, type, and / or severity of one or more impurities, and thereby make a determination as to whether to enable light emission, as described above. Additionally, in some examples, the optical power of the emitted light (e.g., laser) may be reduced as needed to compensate for the optical power that may be lost due to impurities or discontinuities. In some examples, the host processor may provide control signals to the optical system to enable or disable light emission and / or modify the light emission. In some examples, as described herein, the host processor may provide a single-bit message or flag to enable or disable the optical driver (e.g., logic low or logic high). In some examples, the host processor may provide multiple bits to separately control different optical drivers and / or control parameters of the light emission (e.g., intensity). In some examples, the control signals from the host processor may be provided to the optical driver via the acousto-optic integrity detection circuit 206.

[0086] Although the host processor described herein is configured to process signal data and provide control signals, in some examples, some or all of these functions may be provided by the acousto-optic integrity detection circuit 206. In some examples, the acousto-optic integrity detection circuit 206 may process the signal data to determine the location, type, and / or severity of the impurities, and the host processor may generate control signals based on the location, type, and / or severity of the impurities. In some examples, the acousto-optic integrity detection circuit 206 may use the location, type, and / or severity of the impurities to generate control signals. In some examples, the acousto-optic integrity detection circuit 206 may provide the location, type, and / or severity of the impurities to a processor or sub-processor that may be configured to control light emission.

[0087] In some examples, the disclosed acoustic integrity detection system and method may additionally or alternatively be configured to monitor the optical characteristics of the light emitted from one or more light emitters. As an example, when light (e.g., laser) propagates through the lens of the MLA, through one or more transducers, and through the display layer, the piezoelectric layers of one or more transducers (of the ultrasonic sensing layer) may heat up (due to the material properties of the piezoelectric layer (e.g., the pyroelectric properties of ZnO)). As the piezoelectric layers heat up, the piezoelectric layers may each generate a voltage proportional to the temperature of the corresponding layer. Thus, the generated voltage may be measured (continuously) to monitor the temperature of the piezoelectric layers, such that the light intensity of the light propagating through the lens of the MLA can be evaluated. For example, the evaluation of the light intensity of the laser may thus enable the monitoring and evaluation of the optical power transmitted / output from one or more light emitters.

[0088] Accordingly, as described herein, one advantage of the disclosed acoustic integrity detection system and method is that impurities or discontinuities in the geometric optical components of an optical system can be reliably detected and evaluated, which can enable the geometric optical components to be corrected, replaced, and / or repaired. One advantage of the disclosed acoustic integrity detection system and method is that impurities or discontinuities in the optical components of an optical system can be effectively and reliably detected, which can enable the illumination system to be controlled for safe and efficient light emission within the device. One advantage of the disclosed acoustic integrity detection system and method is that an illumination system having a geometric optical device such as a microlens array (e.g., a non-planar optical device) has fault protection, which can achieve higher light power emission and thus greater device performance. One advantage of the disclosed acoustic integrity detection system and method is that due to the low cost and high-performance output of the geometric optical device and the integration of fault protection of the geometric optical device, a high-power illumination system can be provided for the device at a lower cost, which can help prevent situations of light power loss. One advantage of the disclosed acoustic integrity detection system and method is that since a reliable acoustic integrity detection system can be provided for the geometric optical device of the device, product compliance can be significantly improved in the field and thus user safety can be improved.

[0089] Accordingly, in accordance with the above, some examples of the present disclosure relate to an electronic device. The electronic device may include: a display; a lens array including one or more lenses; and one or more ultrasonic transducers coupled between the lens array and the display. The one or more ultrasonic transducers may be configured to generate one or more ultrasonic waves propagating to the lens array and receive one or more reflections of the ultrasonic waves from the lens array.

[0090] Additionally or alternatively, in some examples, the electronic device may further include a processor communicatively coupled to the one or more ultrasonic transducers. The processor may be configured to: use the one or more reflections of the ultrasonic waves to determine the integrity of an optical system including the lens array.

[0091] Additionally or alternatively, in some examples, determining the integrity of the optical system may include: detecting one or more characteristics of the one or more reflections of the ultrasonic waves; and comparing the one or more characteristics of the one or more reflections with one or more predefined thresholds.

[0092] Additionally or alternatively, in some examples, the one or more characteristics of the one or more reflections may include peaks, valleys, wavelengths, amplitudes, or periods.

[0093] Additionally or alternatively, in some examples, the electronic device may further include: one or more light emitters disposed below the lens array. The one or more light emitters may be configured to emit light. The light emitted by the one or more light emitters may be configured to propagate through the one or more lenses of the lens array, through the one or more ultrasonic transducers coupled to the lens array, and / or through the display.

[0094] Additionally or alternatively, in some examples, the one or more light emitters may include one or more lasers.

[0095] Additionally or alternatively, in some examples, the electronic device may further include: a processor coupled to the one or more transducers. The processor may be configured to: enable the one or more light emitters to emit light based on determining that the one or more reflections satisfy one or more integrity criteria, and disable the one or more light emitters from emitting light based on determining that the one or more reflections fail to satisfy the one or more integrity criteria. Additionally or alternatively, in some examples, enabling the one or more light emitters to emit light may include generating a first control signal (e.g., from the host processor or the acousto-optic integrity detection circuit) and transmitting the first control signal to a driver configured to drive the one or more light emitters. Additionally or alternatively, in some examples, disabling the one or more light emitters from emitting light includes generating a second control signal different from the first control signal (e.g., from the host processor or the acousto-optic integrity detection circuit) (e.g., using different logic levels or different bits on separate one or more lines or on one or more shared lines), and transmitting the second control signal to the driver.

[0096] Additionally or alternatively, in some examples, the one or more lenses of the lens array may include glass or epoxy resin.

[0097] Additionally or alternatively, in some examples, the one or more transducers may include: a first piezoelectric layer; a first electrode layer disposed on one side of the first piezoelectric layer; and a second electrode layer disposed on a second side of the first piezoelectric layer opposite the first side of the first piezoelectric layer.

[0098] Additionally or alternatively, in some examples, the one or more transducers may include: a second piezoelectric layer; and a third electrode layer. The second electrode layer may be disposed on a first side of the second piezoelectric layer and the third electrode layer may be disposed on a second side of the second piezoelectric layer opposite the first side of the second piezoelectric layer. The second electrode layer may be configured as a ground electrode.

[0099] Additionally or alternatively, in some examples, the electronic device may further include: a first adhesive layer between the display and the one or more transducers; and a second adhesive between the one or more transducers and the lens array.

[0100] Additionally or alternatively, in some examples, the electronic device may further include a substrate disposed between the lens array and the one or more transducers. The one or more transducers may be formed on the substrate.

[0101] Some examples of the present disclosure relate to a method for detecting optical integrity. The method may include: at an electronic device including a display, a lens array including one or more lenses, and one or more ultrasonic transducers coupled between the lens array and the display: generating one or more ultrasonic waves that propagate from the one or more transducers to the lens array; receiving one or more reflections of the ultrasonic waves from the lens array; and using the one or more reflections of the ultrasonic waves to determine the integrity of an optical system including the lens array.

[0102] Additionally or alternatively, in some examples, determining the integrity of the optical system may include: detecting one or more characteristics of the one or more reflections of the ultrasonic waves; and comparing the one or more characteristics of the one or more reflections with one or more predefined thresholds.

[0103] Additionally or alternatively, in some examples, the one or more characteristics of the one or more reflections may include peaks, valleys, wavelengths, amplitudes, or periods.

[0104] Additionally or alternatively, in some examples, the electronic device may further include: one or more light emitters disposed below the lens array. The one or more light emitters may be configured to emit light. The light emitted by the one or more light emitters may be configured to propagate through the one or more lenses of the lens array, through the one or more ultrasonic transducers coupled to the lens array, and / or through the display.

[0105] Additionally or alternatively, in some examples, the method may further include: enabling the one or more light emitters to emit light based on determining that the one or more reflections meet one or more integrity criteria; and disabling the one or more light emitters from emitting light based on determining that the one or more reflections fail to meet the one or more integrity criteria.

[0106] Additionally or alternatively, in some examples, the one or more transducers of the electronic device may include: a first piezoelectric layer; a first electrode layer disposed on one side of the first piezoelectric layer; and a second electrode layer disposed on a second side of the first piezoelectric layer opposite the first side of the first piezoelectric layer.

[0107] Additionally or alternatively, in some examples, the one or more transducers of the electronic device may include: a second piezoelectric layer; and a third electrode layer. The second electrode layer may be disposed on a first side of the second piezoelectric layer and the third electrode layer may be disposed on a second side of the second piezoelectric layer opposite the first side of the second piezoelectric layer. The second electrode layer may be configured as a ground electrode.

[0108] Some examples of the present disclosure relate to a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium may store instructions that, when executed by an electronic device including a display, one or more light emitters, a lens array including one or more lenses, one or more ultrasonic transducers coupled between the lens array and the display, and processing circuitry, may cause the electronic device to perform any of the methods described above.

[0109] Although the examples of the present disclosure have been described fully with reference to the accompanying drawings, it should be noted that various changes and modifications will become apparent to those skilled in the art. It should be understood that such changes and modifications are considered to be included within the scope of the examples of the present disclosure as defined by the appended claims.

Claims

1. An electronic device, comprising: A display; A lens array; One or more ultrasonic transducers coupled between the lens array and the display; And A detection circuit, wherein the detection circuit is configured to excite the one or more ultrasonic transducers to generate one or more ultrasonic waves that propagate to the lens array, and the detection circuit is configured to receive one or more reflections of the one or more ultrasonic waves from the lens array.

2. The electronic device according to claim 1, further comprising: A processor in communication with the one or more ultrasonic transducers, the processor being configured to: Use the one or more reflections of the one or more ultrasonic waves to determine the integrity of an optical system including the lens array.

3. The electronic device according to claim 2, wherein determining the integrity of the optical system comprises: Detect one or more characteristics of the one or more reflections of the one or more ultrasonic waves; And Compare the one or more characteristics of the one or more reflections with one or more predefined thresholds.

4. The electronic device according to claim 3, wherein the one or more features of the one or more reflections include peaks, valleys, wavelengths, amplitudes, or periods.

5. The electronic device according to claim 2, further comprising: One or more light emitters disposed below the lens array, the one or more light emitters being configured to emit light; Wherein the light emitted by the one or more light emitters is configured to propagate through one or more lenses of the lens array, through the one or more ultrasonic transducers coupled to the lens array, and through the display.

6. The electronic device according to claim 5, wherein the one or more light emitters include one or more lasers.

7. The electronic device according to claim 5, further comprising: A processor, the processor being coupled to the one or more ultrasonic transducers and being configured to: Enable the one or more light emitters to emit light based on determining that the one or more reflections meet one or more integrity criteria; And Disable the one or more light emitters from emitting light based on determining that the one or more reflections fail to meet the one or more integrity criteria.

8. The electronic device according to claim 1, wherein one or more lenses of the lens array include glass or epoxy resin.

9. The electronic device according to claim 1, wherein the one or more ultrasonic transducers include: A first piezoelectric layer; A first electrode layer disposed on a first side of the first piezoelectric layer; And A second electrode layer disposed on a second side of the first piezoelectric layer opposite the first side of the first piezoelectric layer.

10. The electronic device according to claim 9, wherein the one or more ultrasonic transducers include: A second piezoelectric layer; And A third electrode layer, wherein the second electrode layer is disposed on a first side of the second piezoelectric layer, and the third electrode layer is disposed on a second side of the second piezoelectric layer opposite the first side of the second piezoelectric layer, and wherein the second electrode layer is configured as a ground electrode.

11. The electronic device according to claim 1 further comprises: A first adhesive layer between the display and the one or more ultrasonic transducers; And A second adhesive between the one or more ultrasonic transducers and the lens array.

12. The electronic device according to claim 10 further comprises: A substrate disposed between the lens array and the one or more ultrasonic transducers, wherein the one or more ultrasonic transducers are formed on the substrate.

13. A method comprising: At an electronic device including a display, a lens array, and one or more ultrasonic transducers coupled between the lens array and the display: Generate one or more ultrasonic waves that propagate from the one or more ultrasonic transducers to the lens array; Receive one or more reflections of the one or more ultrasonic waves from the lens array; And Use the one or more reflections of the one or more ultrasonic waves to determine the integrity of an optical system including the lens array.

14. The method according to claim 13, wherein determining the integrity of the optical system comprises: Detect one or more characteristics of the one or more reflections of the one or more ultrasonic waves; And Compare the one or more characteristics of the one or more reflections with one or more predefined thresholds.

15. The method according to claim 14, wherein the one or more features of the one or more reflections comprise peaks, valleys, wavelengths, amplitudes or periods.

16. The method according to claim 13, wherein the electronic device further comprises: One or more light emitters disposed below the lens array, the one or more light emitters being configured to emit light; Wherein the light emitted by the one or more light emitters is configured to propagate through one or more lenses of the lens array, through the one or more ultrasonic transducers coupled to the lens array, and through the display.

17. The method according to claim 16 further comprises: Enable the one or more light emitters to emit light based on determining that the one or more reflections meet one or more integrity criteria; And Disable the one or more light emitters from emitting light based on determining that the one or more reflections fail to meet the one or more integrity criteria.

18. The method according to claim 13, wherein the one or more ultrasonic transducers of the electronic device comprise: A first piezoelectric layer; A first electrode layer disposed on a first side of the first piezoelectric layer; And A second electrode layer disposed on a second side of the first piezoelectric layer opposite the first side of the first piezoelectric layer.

19. The method according to claim 18, wherein the one or more ultrasonic transducers of the electronic device comprise: A second piezoelectric layer; And A third electrode layer, wherein the second electrode layer is disposed on a first side of the second piezoelectric layer, and the third electrode layer is disposed on a second side of the second piezoelectric layer opposite the first side of the second piezoelectric layer, and wherein the second electrode layer is configured as a ground electrode.

20. A non-transitory computer-readable storage medium storing instructions that, when executed by an electronic device including a display, one or more light emitters, a lens array, one or more ultrasonic transducers coupled between the lens array and the display, and a processing circuit, cause the electronic device to: generate one or more ultrasonic waves propagating from the one or more ultrasonic transducers to the lens array; receive one or more reflections of the one or more ultrasonic waves from the lens array; Enable the one or more light emitters to emit light based on determining that the one or more reflections meet one or more integrity criteria; And Disable the one or more light emitters from emitting light based on determining that the one or more reflections fail to meet the one or more integrity criteria.

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