Piezoelectric film partition dynamic focusing system and method for intelligent glasses

Abstract

The invention discloses a piezoelectric film partition dynamic focusing system and method for intelligent glasses. The piezoelectric film partition dynamic focusing system comprises an optical modulation layer, a sensing layer, a control engine, a hybrid driving layer and a closed loop verification module. The optical modulation layer is integrated with an N * M piezoelectric film array, each subarea is provided with an independent electrode and a gradient thickness structure, and intervals are filled with low-modulus insulating polymers. The sensing layer is used for acquiring fixation point, diopter, temperature and head movement information of a wearer; and the control engine executes voltage mapping, temperature drift compensation and resonance suppression according to the sensing data, and drives the hybrid driving layer to complete deformation and displacement compensation. And the closed-loop verification module outputs a defocusing error in real time and feeds back a correction voltage. According to the invention, high-response, low-power-consumption and stable dynamic focusing is realized, and the visual adaptability is improved.

Description

Technical Field

[0001] This invention relates to the field of smart glasses technology, and in particular to a piezoelectric thin film zoned dynamic focusing system and method for smart glasses. Background Technology

[0002] With the rapid development of smart wearable devices, smart glasses, as an important component of augmented reality (AR), virtual reality (VR), and human-computer interaction (HCI) platforms, are gradually moving from laboratory products to the consumer market. Focusing capability, as one of the key performance indicators affecting wearer visual comfort and interactive experience, has become an important research direction for smart glasses systems. Currently, some technical solutions have attempted to achieve zoom functionality by introducing liquid crystal lenses, liquid lenses, and MEMS lenses, but they generally suffer from the following problems: 1. Slow focusing response speed: Liquid crystal lenses rely on an electric field to rearrange liquid crystal molecules to complete focus adjustment. The response time is usually tens to hundreds of milliseconds, which is difficult to meet the dynamic focusing requirements when the eye moves quickly and the gaze point switches. 2. Complex system integration: Liquid lenses require high-precision packaging control and liquid cavity structure, which makes integration difficult and hinders their promotion in lightweight devices such as eyeglasses. 3. Insufficient focusing accuracy and stability: Existing technologies are generally unable to achieve high-resolution dynamic focusing for eye movement positions. Especially when the wearer moves quickly, there are temperature fluctuations or device resonance interference, the focus control accuracy decreases and the visual error increases. 4. Energy consumption and lagging control algorithms: Although some schemes based on continuously deformable materials (such as electroactive polymers) or global piezoelectric films have certain deformation capabilities, their control strategies rely on centralized computing and cannot respond in real time to partitioned optical compensation and temperature drift errors.

[0003] Therefore, existing smart glasses focusing systems still have significant technical shortcomings in terms of real-time performance, stability, energy efficiency, and adaptability. There is an urgent need for a new focusing solution with high response speed, dynamic controllability of zones, strong anti-interference ability, and closed-loop feedback correction to improve the visual interaction quality of smart glasses in complex usage environments. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a piezoelectric thin film zoned dynamic focusing system and method for smart glasses, which achieves high response, low power consumption, and stable dynamic focusing, thereby improving visual adaptability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a piezoelectric thin film zoned dynamic focusing system for smart glasses, comprising: An optical modulation layer includes a transparent substrate and an integrated N×M piezoelectric thin film array. The piezoelectric thin film array includes multiple piezoelectric partitions, each of which has an independent electrode and a gradient thickness structure. A laser-cut microgroove is provided between adjacent independent electrodes, and the laser-cut microgroove is filled with an insulating polymer with an elastic modulus of <1 GPa. The sensing layer, physically connected to the edge of the optical modulation layer, includes: The eye-tracking module projects a scanning beam onto the retina of the smart glasses wearer via an infrared MEMS micromirror and receives the reflected light spot to calculate the coordinates of the gaze point and the refractive power. Temperature sensor array, used to detect and obtain zone temperature data; The motion detection module is used to collect the head motion acceleration spectrum of the wearer of the smart glasses; The control engine, connected to the sensing layer via a digital bus, includes: The dynamic partition mapping unit is used to output an initial voltage mapping table and displacement compensation amount for the target partition based on the gaze point coordinates and the refractive power, and to generate a displacement compensation instruction based on the displacement compensation amount. The initial voltage mapping table contains the initial voltage. The hysteresis temperature drift compensation unit is used to input the initial voltage, the zone temperature data and the historical deformation direction mark into a preset voltage correction formula to generate a voltage correction value, and then generate a voltage correction command based on the voltage correction value. A hybrid driving layer, mechanically coupled to the bottom of the optical modulation layer and connected to the control engine via a digital bus, includes: A piezoelectric actuator, with its output terminal electrically connected to each of the independent electrodes, is used to drive a thin film to produce localized deformation according to the voltage correction command. MEMS micro-displacement platform, used to perform displacement compensation according to the displacement compensation command; The control engine also includes a resonance suppression unit, used to dynamically adjust the driving frequency of the piezoelectric actuator during the voltage driving process according to the acceleration spectrum of the head movement; The closed-loop verification module, connected to the control engine, includes a phase detection pixel array distributed at the edge of the optical modulation layer, used to output the defocus error and feed it back to the hysteresis temperature drift compensation unit to trigger secondary voltage correction.

[0006] Furthermore, the depth of the laser-cut microgroove is 35% ± 2% of the thickness of the piezoelectric partition, the inclination angle of the groove wall of the laser-cut microgroove is in the range of 85°-88°, and the insulating polymer filled in it is polydimethylsiloxane doped with 15wt% titanium dioxide nanoparticles, and the elastic modulus of the insulating polymer is 0.8 ± 0.1 GPa.

[0007] Furthermore, the formula for calculating the displacement compensation amount is configured as follows: ; in, This indicates the displacement compensation amount. This indicates the refractive power at the fixation point. This represents the deformation gradient of the target partition. This represents the magnitude of the temperature gradient in the target zone.

[0008] Furthermore, the voltage correction formula is as follows: ; in, This indicates the corrected voltage value. This represents the initial voltage. This represents the temperature data of the partition. This indicates the preset calibration temperature. Indicates the direction of historical deformation. Used to reflect the hysteresis effect This indicates the acceleration of piezoelectric film deformation.

[0009] Furthermore, when the resonance suppression unit detects that the energy integral E in the 40-60Hz frequency band is greater than 0.3g² / Hz, it switches the driving frequency to 55Hz or 45Hz, with a switching response time of ≤2ms. Where E represents the integral value of vibration energy in the 40-60Hz frequency band, with the unit being g² / Hz, and g represents the acceleration due to gravity.

[0010] Furthermore, the formula for calculating the defocus error of the phase detection pixel array is configured as follows: ; in, This indicates the defocus error. This represents the detection phase difference of the i-th photodiode. This indicates the preset reference phase difference.

[0011] Furthermore, when the hysteresis temperature drift compensation unit performs secondary voltage correction, it receives the defocusing error and the partition identifier corresponding to the piezoelectric partition; The piezoelectric partition satisfies When, an emergency correction flag is generated for that partition. At that time, a periodic correction flag is generated; During emergency correction, based on the partition temperature data, the historical deformation direction markers, and the defocusing error, the voltage is updated using an incremental formula, which is configured as follows: ; During the periodic correction process, in the next driving cycle, the corresponding value in the initial voltage mapping table is updated using the defocus error as input. The voltage value; If the same piezoelectric zone triggers three consecutive emergency corrections, the piezoelectric film corresponding to that piezoelectric zone is determined to be abnormal, and the system switches to the adjacent zone compensation mode.

[0012] Furthermore, the calculation of the refractive power satisfies: ; in, This indicates the refractive power at the fixation point. This represents the ellipticity of the reflected light spot. This represents the entropy of the light intensity distribution of the reflected light spot. This represents the proportion of light intensity in the k-th pixel region. This indicates the total number of pixel regions.

[0013] Furthermore, when the piezoelectric actuator drives the target partition, the bias voltage of the adjacent partitions satisfies: ; in, This refers to the bias voltage applied to adjacent partitions. This indicates the peak value of the PWM drive voltage in the high-voltage region.

[0014] A piezoelectric thin film zoned dynamic focusing method for smart glasses, applied to the aforementioned piezoelectric thin film zoned dynamic focusing system for smart glasses, comprising: Step S1: The eye-tracking module projects a scanning beam onto the retina of the smart glasses wearer through an infrared MEMS micromirror and receives the reflected light spot to calculate the coordinates of the gaze point and the refractive power. Step S2: The temperature sensor array detects and obtains the zoned temperature data, and the motion detection module collects the head motion acceleration spectrum of the smart glasses wearer. Step S3: The dynamic partition mapping unit outputs an initial voltage mapping table and displacement compensation amount for the target partition based on the gaze point coordinates and the refractive power, and generates a displacement compensation command based on the displacement compensation amount. The initial voltage mapping table contains the initial voltage. Step S4: The hysteresis temperature drift compensation unit inputs the initial voltage, the zone temperature data and the historical deformation direction mark into a preset voltage correction formula to generate a voltage correction value, and then generates a voltage correction command based on the voltage correction value. Step S5: The piezoelectric actuator drives the thin film to produce local deformation according to the voltage correction command, the MEMS micro-displacement platform performs displacement compensation according to the displacement compensation command, and the resonance suppression unit dynamically adjusts the driving frequency of the piezoelectric actuator in the voltage driving process according to the acceleration spectrum of the head motion. In step S6, the closed-loop verification module outputs the defocus error and feeds it back to the hysteresis temperature drift compensation unit to trigger a secondary voltage correction.

[0015] The beneficial effects of this invention are: (1) High-precision dynamic focusing: By dividing the piezoelectric thin film array into multiple micro-partitions with independent electrode control, combined with gaze point positioning information, fine focusing of the wearer's field of vision area is achieved, improving visual clarity and interactive response speed.

[0016] (2) It has the ability to compensate for temperature drift and magnetic hysteresis: By introducing a magnetic hysteresis temperature drift compensation unit, integrating temperature data, historical deformation state and voltage mapping, it can realize the focal length stability control under environmental changes, which significantly improves the adaptability and reliability of the system.

[0017] (3) Suppressing resonance interference: By dynamically adjusting the driving frequency of the piezoelectric actuator through the resonance suppression unit, the mechanical resonance caused by the wearer's head movement can be effectively suppressed, ensuring image stability during focusing.

[0018] (4) Supports closed-loop self-correction: The system can automatically adjust the voltage according to the defocus error by using a closed-loop verification module composed of a phase detection pixel array, thereby achieving precise feedback control and improving the overall focusing accuracy and adaptive capability.

[0019] (5) Fast response speed and low power consumption: Based on the piezoelectric driving principle, the response speed is far superior to that of liquid crystal or liquid lens systems. At the same time, energy consumption is reduced by local focusing in partitioned areas, making it suitable for continuous operation in daily wear scenarios. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the piezoelectric thin film zoned dynamic focusing system for smart glasses in this invention; Figure 2 This is a flowchart of the steps of the piezoelectric thin film partitioned dynamic focusing method for smart glasses in this invention.

[0021] Reference numerals: 1. Optical modulation layer; 2. Sensing layer; 3. Eye tracking module; 4. Temperature sensing array; 5. Motion detection module; 6. Control engine; 61. Dynamic partition mapping unit; 62. Hysteresis temperature drift compensation unit; 63. Resonance suppression unit; 7. Hybrid driving layer; 71. Piezoelectric actuator; 72. MEMS micro-displacement platform; 8. Closed-loop verification module. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Identical components are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom surface," "top surface," "inner," and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0023] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a piezoelectric thin film zoned dynamic focusing system for smart glasses, capable of achieving high response, low power consumption, and stable dynamic focusing, thereby improving visual adaptability, including: Optical modulation layer 1, disposed in the lens area of ​​the smart glasses, includes a transparent substrate and an N×M piezoelectric thin film array integrated thereon. The piezoelectric thin film array is divided into multiple piezoelectric zones, each zone having an independent electrode and a gradient thickness structure to achieve controllable deformation within the region. Laser-cut microgrooves are provided between each electrode, and the microgrooves are filled with an insulating polymer with an elastic modulus of less than 1 GPa for electrical insulation and deformation buffering.

[0024] Sensing layer 2, installed inside the frame and connected to the edge of optical modulation layer 1, includes the following components: Eye-tracking module 3: It projects a scanning beam onto the wearer's retina through an infrared MEMS micromirror and receives the reflected light spot. Based on the echo data, it calculates the coordinates of the current gaze point and the corresponding refractive information.

[0025] Temperature sensing array 4: Attached to the edge region of the piezoelectric thin film array, it monitors the temperature of each zone in real time and provides temperature drift compensation data.

[0026] Motion detection module 5: integrates a three-axis accelerometer and gyroscope to collect the wearer's head motion state and obtain the resonance trend through spectrum analysis.

[0027] Control engine 6, located inside the temple, is electrically connected to sensing layer 2 and drive layer, and includes: Dynamic partition mapping unit 61: Based on the gaze point coordinates and refractive information obtained from eye tracking, determine the target focusing area and output the initial voltage mapping table and displacement compensation amount of the area; Hysteresis temperature drift compensation unit 62: Inputs the initial voltage, real-time temperature data and historical deformation direction into the voltage correction model, and outputs the corrected voltage value; Resonance suppression unit 63: Based on the spectral analysis results of head motion, dynamically adjust the driving frequency of piezoelectric actuator 71 to avoid system resonance; Voltage and displacement control module: Sends correction voltage and displacement compensation commands to hybrid drive layer 7.

[0028] Hybrid driving layer 7, which is in close contact with the back side of optical modulation layer 1, includes: Piezoelectric actuator 71: Connected to the independent electrodes of each zone, it drives the corresponding piezoelectric zone to undergo local deformation according to the correction voltage command, thereby realizing the local curvature adjustment of the lens; MEMS Micro-displacement Platform 72: Performs fine adjustments to the overall or partial lens position according to displacement compensation commands to compensate for mechanical errors or structural disturbances.

[0029] The closed-loop verification module 8 includes a phase detection pixel array embedded in the edge region of the optical modulation layer 1. It is used to detect the phase deviation of the current image, output the defocus error, and feed it back to the hysteresis temperature drift compensation unit 62 for secondary voltage correction, thereby realizing closed-loop focusing.

[0030] Working principle of Example 1: The motion tracking module acquires the gaze point position and required refractive power in real time; the dynamic partition mapping unit 61 in the control engine 6 determines the piezoelectric partition that needs to be focused and generates the corresponding initial voltage; the temperature sensor array 4 collects the ambient temperature and, in conjunction with the historical deformation state, the hysteresis temperature drift compensation unit 62 generates a correction voltage; the head motion detection module 5 outputs the acceleration spectrum, which is used by the resonance suppression unit 63 to adjust the piezoelectric drive frequency; the piezoelectric actuator 71 drives the corresponding piezoelectric partition film to deform according to the correction voltage, changing the local curvature of the lens and completing real-time focusing; if there is a focal length deviation, the phase detection pixel array feeds back the error signal, triggering a second voltage correction, thus forming a closed-loop control.

[0031] This embodiment features rapid response, zone control, anti-interference, and closed-loop precision functions, effectively improving the wearer's visual clarity and comfort under different viewing angles and dynamic environments.

[0032] Preferably, in this embodiment, the depth of the laser-cut microgroove is 35%±2% of the thickness of the piezoelectric partition, the inclination angle of the microgroove wall is in the range of 85°-88°, and the insulating polymer it is filled with is polydimethylsiloxane doped with 15wt% titanium dioxide nanoparticles, and the elastic modulus of the insulating polymer is 0.8±0.1GPa.

[0033] Specifically, in this embodiment, when the overall thickness of the piezoelectric partition is 10 μm, the depth of the laser microgroove is controlled within the range of 3.3 μm to 3.7 μm. This depth ratio achieves good electrical insulation while avoiding excessive weakening of the mechanical strength of the piezoelectric film; The inclination angle of the microgroove walls is set between 85° and 88° to optimize filler penetration and structural support strength. This inclination angle range effectively controls the cross-sectional shape of the microgroove, improves polymer filling uniformity, and prevents dielectric breakdown caused by edge voids or stress concentration.

[0034] The interior of the laser-cut microgroove is filled with a modified elastic insulating material, which is polydimethylsiloxane (PDMS) doped with 15 wt% titanium dioxide (TiO2) nanoparticles. This composite material has both excellent flexibility and high dielectric insulation properties, and can provide a certain morphology recovery force during the micro-deformation of the piezoelectric partition, which helps to stabilize the morphology of the microgroove region.

[0035] The elastic modulus of the filler polymer is controlled at 0.8±0.1 GPa to ensure that it can buffer stress during local deformation of the piezoelectric zone without hindering the normal deformation of the film layer, while improving the fatigue life and stability of the overall system.

[0036] Through the above structural optimization, the laser-cut microgroove design in this embodiment significantly improves the electrical isolation, mechanical integrity, and focusing repeatability of the piezoelectric thin film array, thereby enhancing the system's reliability and optical consistency in long-term dynamic use scenarios.

[0037] Preferably, the formula for calculating the displacement compensation is configured as follows: ; in, This indicates the amount of displacement compensation. Indicates the refractive power at the fixation point. This represents the deformation gradient of the target partition. This represents the magnitude of the temperature gradient in the target zone. The exponential term is used to dynamically adjust the gradient sensitivity to avoid displacement distortion caused by temperature changes.

[0038] Specifically, in this embodiment, the calculation method integrates optical focusing requirements with thermal-deformation coupling characteristics to ensure that the compensation amount is highly matched with the actual physical state, thereby improving the dynamic focusing accuracy.

[0039] Preferably, the voltage correction formula is: ; in, Indicates the corrected voltage value. Indicates the initial voltage. This indicates the current partition temperature data. This indicates the preset calibration temperature. Indicates the direction of historical deformation. Used to reflect the hysteresis effect This represents the deformation acceleration of the piezoelectric film, which is the second-order deformation of the piezoelectric film per unit time, i.e., the deformation acceleration, and is used to compensate for the inertial offset caused by high-speed dynamic focusing.

[0040] Specifically, in this embodiment, the modified model effectively integrates the effects of thermal drift, hysteresis memory characteristics, and dynamic inertia factors, enabling the system to maintain high stability and high-precision output even when rapidly switching gaze points.

[0041] Preferably, the resonance suppression unit 63 performs a fast Fourier transform (FFT) on the acceleration signal collected by the motion detection module 5 to calculate the energy integral in the 40–60 Hz frequency band. When the energy integral E in the 40–60 Hz frequency band is detected to be greater than 0.3 g² / Hz, the system determines that the current head movement or external vibration may cause structural resonance. The control engine 6 automatically switches the driving frequency of the piezoelectric actuator 71 to 55 Hz or 45 Hz to avoid the resonance frequency point. The switching response time is ≤2 ms, ensuring that the focusing drive process is not affected by resonance. Where E represents the integral value of vibration energy in the 40-60Hz frequency band, with the unit being g² / Hz, and g represents the acceleration due to gravity.

[0042] Specifically, in this embodiment, a mechanism for rapid identification and avoidance of resonant frequency bands is implemented to enhance the robustness of the system and prevent the wearer from experiencing focusing deviations or image blurring during strenuous exercise.

[0043] Example 2, refer to Figure 2 This is the second embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a closed-loop focusing system integrating error identification and dynamic correction mechanisms. It is suitable for high-precision operation of piezoelectric thin-film zoned dynamic focusing systems in complex environments, and includes: The formula for calculating the defocus error of the phase detection pixel array is configured as follows: ; in, Indicates defocus error. This represents the detection phase difference of the i-th photodiode. The preset reference phase difference is obtained by calibrating the system under optimal focusing conditions.

[0044] Specifically, in this embodiment, the optical phase difference of the target area is detected by a phase detection pixel array disposed at the edge of the optical modulation layer, and the phase detection pixel array includes four photodiodes. The defocus error calculation method can quickly quantify the degree of defocus in the area, adapting to the focus error identification requirements under dynamic gaze changes.

[0045] The hysteresis temperature drift compensation unit 62 receives the defocus error value corresponding to each piezoelectric zone and performs the following two correction mechanisms based on its amplitude: Urgent fix: Piezoelectric zoning is now satisfied. At that time, an emergency correction label is generated for that partition; During the emergency correction process, based on zone temperature data, historical deformation direction indicators, and defocusing error, the voltage is updated using an incremental formula, configured as follows: ; If the same piezoelectric zone triggers three consecutive emergency corrections, the piezoelectric film corresponding to that piezoelectric zone is determined to be abnormal, and the system switches to the compensation mode for the adjacent zone.

[0046] Periodic correction: when At that time, a period correction flag is generated. During the period correction process, in the next driving cycle, the corresponding value in the initial voltage mapping table is updated using the defocus error as input. The voltage value, to the corresponding triplet in the initial voltage mapping table. The above settings can be used to correct the defocus error and ensure that the focal length accuracy is maintained during long-term use.

[0047] Preferably, the refractive power is calculated by the eye-tracking module 3 based on the reflected light spot image detected and its shape and light intensity distribution, according to the following formula: ; in, Indicates the refractive power at the fixation point. The ellipticity of the reflected light spot is represented by its eccentricity. The entropy represents the intensity distribution of the reflected light spot. This represents the proportion of light intensity in the k-th pixel region. This method, which integrates geometric features and statistical optical properties, effectively improves the resolution and robustness of diopter detection, representing the total number of pixel regions.

[0048] Preferably, to avoid the electric field interference generated when driving a certain target piezoelectric zone from affecting adjacent areas, this system introduces a reverse bias voltage to adjacent zones, calculated as follows: ; in, This represents the bias voltage applied to adjacent partitions. This indicates the peak value of the PWM drive voltage in the high-voltage region.

[0049] Specifically, in this embodiment, the strategy can effectively suppress electric field coupling and micro-mechanical resonance, and improve the spatial separation of the overall focusing control.

[0050] Working principle of Example 2: In actual use, when the wearer's gaze direction changes: the eye-tracking module 3 obtains the current gaze point coordinates and calculates the refractive power through the reflected light spot image; the control engine 6 updates the focusing target area accordingly and issues the initial drive voltage; after focusing, the phase detection pixel array located at the edge of the lens measures the phase deviation of the focusing area and calculates it; the compensation module performs emergency or periodic correction according to the error level and switches to adjacent partitions when necessary; if the system detects an abnormality in a piezoelectric area, it activates adjacent areas to perform deformation relay; at the same time, the adjacent partitions are biased to isolate interference and ensure the stability of the focusing process; the whole system forms a closed-loop self-feedback control path to achieve high-precision, low-error dynamic real-time focusing.

[0051] A piezoelectric thin film zone dynamic focusing method for smart glasses, applied to the aforementioned piezoelectric thin film zone dynamic focusing system for smart glasses, with reference to... Figure 2 ,include: Step S1: The eye-tracking module 3 projects a scanning beam onto the retina of the smart glasses wearer through an infrared MEMS micromirror and receives the reflected light spot to calculate the coordinates of the gaze point and the refractive power. In step S2, the temperature sensor array 4 detects the zoned temperature data, and the motion detection module 5 collects the head motion acceleration spectrum of the smart glasses wearer. Step S3: The dynamic partition mapping unit 61 outputs the initial voltage mapping table and displacement compensation amount of the target partition according to the gaze point coordinates and the refractive power, and generates a displacement compensation command according to the displacement compensation amount. The initial voltage mapping table contains the initial voltage. In step S4, the hysteresis temperature drift compensation unit 62 inputs the initial voltage, the zone temperature data and the historical deformation direction mark into a preset voltage correction formula to generate a voltage correction value, and then generates a voltage correction command based on the voltage correction value. In step S5, the piezoelectric actuator 71 drives the thin film to produce local deformation according to the voltage correction command, the MEMS micro-displacement platform 72 performs displacement compensation according to the displacement compensation command, and the resonance suppression unit 63 dynamically adjusts the driving frequency of the piezoelectric actuator 71 in the voltage driving process according to the acceleration spectrum of the head motion. In step S6, the closed-loop verification module 8 outputs the defocus error and feeds it back to the hysteresis temperature drift compensation unit 62 to trigger a secondary voltage correction.

[0052] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A piezoelectric thin film zoned dynamic focusing system for smart glasses, characterized in that, include: An optical modulation layer (1) includes a transparent substrate and an integrated N×M piezoelectric thin film array. The piezoelectric thin film array includes multiple piezoelectric partitions, each of which has an independent electrode and a gradient thickness structure. A laser-cut microgroove is provided between adjacent independent electrodes. The laser-cut microgroove is filled with an insulating polymer with an elastic modulus of <1 GPa. The sensing layer (2), physically connected to the edge of the optical modulation layer (1), includes: The eye-tracking module (3) is used to project a scanning beam onto the retina of the smart glasses wearer through an infrared MEMS micromirror and receive the reflected light spot to calculate the coordinates of the gaze point and the refractive power. Temperature sensing array (4) is used to detect and obtain partition temperature data; The motion detection module (5) is used to collect the head motion acceleration spectrum of the wearer of the smart glasses; The control engine (6), connected to the sensing layer (2) via a digital bus, includes: The dynamic partition mapping unit (61) is used to output the initial voltage mapping table and displacement compensation amount of the target partition according to the gaze point coordinates and the refractive power, and generate a displacement compensation instruction according to the displacement compensation amount. The initial voltage mapping table contains the initial voltage. The hysteresis temperature drift compensation unit (62) is used to input the initial voltage, the partition temperature data and the historical deformation direction mark into a preset voltage correction formula to generate a voltage correction value, and then generate a voltage correction command based on the voltage correction value. A hybrid driving layer (7), mechanically coupled to the bottom of the optical modulation layer (1) and connected to the control engine (6) via a digital bus, includes: The piezoelectric actuator (71) has its output terminal electrically connected to each of the independent electrodes and is used to drive the thin film to produce local deformation according to the voltage correction command. MEMS micro-displacement platform (72) is used to perform displacement compensation according to the displacement compensation command; The control engine (6) also includes a resonance suppression unit (63) for dynamically adjusting the driving frequency of the piezoelectric actuator (71) during the voltage driving process according to the acceleration spectrum of the head movement; The closed-loop verification module (8) is connected to the control engine (6) and includes a phase detection pixel array distributed on the edge of the optical modulation layer (1). It is used to output the defocus error and feed it back to the hysteresis temperature drift compensation unit (62) to trigger the secondary voltage correction.

2. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 1, characterized in that: The depth of the laser-cut microgroove is 35% ± 2% of the thickness of the piezoelectric zone, the inclination angle of the groove wall is in the range of 85°-88°, and the insulating polymer filled in it is polydimethylsiloxane doped with 15wt% titanium dioxide nanoparticles, and the elastic modulus of the insulating polymer is 0.8 ± 0.1 GPa.

3. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 1, characterized in that: The formula for calculating the displacement compensation amount is configured as follows: ; in, This indicates the displacement compensation amount. This indicates the refractive power at the fixation point. The deformation gradient of the target partition is shown. The target zone temperature gradient amplitude is shown.

4. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 1, characterized in that: The voltage correction formula is as follows: ; in, This indicates the corrected voltage value. This represents the initial voltage. This represents the temperature data of the partition. This indicates the preset calibration temperature. Indicates the direction of historical deformation. Used to reflect the hysteresis effect This indicates the acceleration of piezoelectric film deformation.

5. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 1, characterized in that: When the resonance suppression unit detects that the energy integral E in the 40-60Hz frequency band is greater than 0.3g² / Hz, it switches the driving frequency to 55Hz or 45Hz, with a switching response time of ≤2ms. Where E represents the integral value of vibration energy in the 40-60Hz frequency band, with the unit being g² / Hz, and g represents the acceleration due to gravity.

6. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 4, characterized in that: The formula for calculating the defocus error of the phase detection pixel array is configured as follows: ; in, This indicates the defocus error. This represents the detection phase difference of the i-th photodiode. This indicates the preset reference phase difference.

7. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 6, characterized in that: When the hysteresis temperature drift compensation unit performs secondary voltage correction, it receives the defocusing error and the partition identifier corresponding to the piezoelectric partition. The piezoelectric partition satisfies When, an emergency correction flag is generated for that partition. At that time, a periodic correction flag is generated; During emergency correction, based on the partition temperature data, the historical deformation direction markers, and the defocusing error, the voltage is updated using an incremental formula, which is configured as follows: ; During the periodic correction process, in the next driving cycle, the corresponding value in the initial voltage mapping table is updated using the defocus error as input. The voltage value; If the same piezoelectric zone triggers three consecutive emergency corrections, the piezoelectric film corresponding to that piezoelectric zone is determined to be abnormal, and the system switches to the adjacent zone compensation mode.

8. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 1, characterized in that: The calculation of the refractive power satisfies: ; in, The refractive power at the fixation point is shown. This represents the ellipticity of the reflected light spot. This represents the entropy of the light intensity distribution of the reflected light spot. This represents the proportion of light intensity in the k-th pixel region. This indicates the total number of pixel regions.

9. The piezoelectric thin film zoned dynamic focusing system for smart glasses according to claim 1, characterized in that: When the piezoelectric actuator drives the target partition, the bias voltage of the adjacent partitions satisfies: ; in, This refers to the bias voltage applied to adjacent partitions. This indicates the peak value of the PWM drive voltage in the high-voltage region.

10. A piezoelectric thin film zoned dynamic focusing method for smart glasses, applied to the piezoelectric thin film zoned dynamic focusing system for smart glasses according to any one of claims 1-9, characterized in that, include: Step S1, the eye-tracking module (3) projects a scanning beam onto the retina of the smart glasses wearer through an infrared MEMS micromirror and receives the reflected light spot to calculate the coordinates of the gaze point and the refractive power; Step S2, the temperature sensing array (4) detects the partition temperature data, and the motion detection module (5) collects the head motion acceleration spectrum of the smart glasses wearer; Step S3, the dynamic partition mapping unit (61) outputs the initial voltage mapping table and displacement compensation amount of the target partition according to the gaze point coordinates and the refractive power, and generates a displacement compensation instruction according to the displacement compensation amount. The initial voltage mapping table contains the initial voltage. Step S4, the hysteresis temperature drift compensation unit (62) inputs the initial voltage, the partition temperature data and the historical deformation direction mark into the preset voltage correction formula to generate a voltage correction value, and then generates a voltage correction command based on the voltage correction value; In step S5, the piezoelectric actuator (71) drives the thin film to produce local deformation according to the voltage correction command, the MEMS micro-displacement platform (72) performs displacement compensation according to the displacement compensation command, and the resonance suppression unit (63) dynamically adjusts the driving frequency of the piezoelectric actuator (71) in the voltage driving process according to the acceleration spectrum of the head motion. In step S6, the closed-loop verification module (8) outputs the defocus error and feeds it back to the hysteresis temperature drift compensation unit (62) to trigger the secondary voltage correction.

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