Electronic paper display device and afterimage repair method

Abstract

The application provides an electronic paper display device and a residual image repair method, wherein the electronic paper display device comprises a display panel, an acoustic wave transduction array and a control processing unit, the acoustic wave transduction array is integrated on the back plate side of the display panel, in the detection mode, the control processing unit drives the acoustic wave transduction array to emit an ultrasonic detection signal and receive a return signal, extracts a characteristic parameter in the return signal and constructs a return characteristic vector, compares the return characteristic vector with a reference characteristic vector, and realizes residual image identification and repair control operation, so as to apply an ultrasonic repair excitation matched with the abnormal type to an abnormal area, the acoustic wave transduction array is reconstructed into an integrated dual-function module with the functions of active acoustic wave detection and repair excitation application, the timeliness and energy efficiency of residual image elimination are significantly improved, and the power consumption waste caused by invalid driving and the internal structure aging risk of the electronic paper are reduced.

Description

Technical Field

[0001] This invention belongs to the field of electronic paper technology, and particularly relates to an electronic paper display device and a method for repairing image retention. Background Technology

[0002] In the field of display technology, electronic paper, with its outstanding advantages such as low power consumption, paper-like visual effect, and excellent visibility under strong light, is widely used in e-readers, smart office equipment, electronic price tags, automotive displays, industrial instruments, and many other scenarios. As market demands continue to upgrade, electronic paper display technology is gradually developing towards high-speed partial refresh, low-flicker display, and video applications, which also places higher demands on the display quality of electronic paper. However, the problem of image retention remains a key factor restricting the improvement of electronic paper display quality. This problem manifests as the inability to completely eliminate traces of the original image when switching display content after multiple refreshes or long-term display of a fixed pattern, severely affecting the visual experience and limiting the application of electronic paper in high-end display scenarios.

[0003] To address the issue of image retention in electronic paper, various methods have been proposed for image removal, including full-screen refresh, drive waveform optimization, lookup table compensation, and local ultrasonic perturbation. Among these, ultrasonic technology has gained increasing attention for its application in image retention repair. Its working principle involves using piezoelectric transducers to generate mechanical vibrations, local pressure waves, or microfluidic disturbances, which act on the electrophoretic particles inside the electronic paper, reactivating their migration ability, reducing particle aggregation and migration lag, and thus achieving image retention repair. However, existing ultrasonic solutions still have significant technical shortcomings in practical applications. They only use ultrasound as a means of performing the repair, operating in a post-recovery mode, directly triggering ultrasonic perturbation under preset refresh conditions, without the ability to actively sense the state of the electrophoretic particles inside the electronic paper.

[0004] From a technical perspective, existing electronic paper ghosting repair systems still rely on display refresh history, display count, or empirical thresholds to infer the presence and severity of ghosting, failing to directly obtain the true distribution information of electrophoretic particles inside the electronic paper microcup. This indirect inference method easily leads to the inaccurate identification of local ghosting anomalies and inaccurate judgment of repair timing, resulting in problems such as ineffective driving and over-repair. Ineffective driving not only increases the power consumption of electronic paper but also accelerates the aging of the internal structure of electronic paper, shortening the lifespan of the device; while over-repair may cause unnecessary disturbance to the electrophoretic particles in normal display areas, affecting display stability and even exacerbating particle anomalies in some areas. Summary of the Invention

[0005] The purpose of this invention is to provide an electronic paper display device that addresses the problems of low recognition accuracy and untimely repair in traditional electronic paper image restoration methods.

[0006] A first aspect of this invention provides an electronic paper display device, comprising: The display panel includes a microcup electrophoresis layer and a driving layer for driving the microcup electrophoresis layer; An acoustic transducer array is integrated on the back panel side of the display panel. The acoustic transducer array is used to emit ultrasonic detection signals to the microcup electrophoretic layer and receive echo signals returned from inside the microcup electrophoretic layer. Control processing unit, used for: In detection mode, the acoustic transducer array is driven to perform signal transmission and reception, and multiple physical dimension feature parameters are extracted from the echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer, so as to construct an echo feature vector. The echo feature vector is compared with the reference feature vector corresponding to the no-afterimage state to determine whether there is an abnormal particle state in the currently detected area. After determining that there is an abnormal particle state, the repair mode is activated, and a repair driving signal is generated and output to the acoustic transducer array to apply ultrasonic repair excitation that matches the abnormality type to the abnormal area.

[0007] Optionally, the feature parameters of the multiple physical dimensions include at least: Peak amplitude characteristics are used to characterize the reflection intensity of the echo signal; The time-of-flight characteristic is used to characterize the time difference between the arrival time of the main reflected echo in the echo signal and the emission time of the ultrasonic detection signal, so as to reflect the position of the reflective interface inside the microcup electrophoretic layer. The cumulative echo energy characteristic is used to characterize the energy integral of the echo signal within a preset time window, so as to reflect the degree of aggregation of the electrophoretic particles; Echo attenuation characteristics are used to characterize the amplitude attenuation relationship between echoes generated by different reflecting interfaces in the echo signal, so as to reflect the propagation loss of ultrasound in the electrophoretic particle region.

[0008] Optionally, the acoustic transducer array includes multiple piezoelectric transducer units; The control processing unit is further configured to: Addressing scans are performed on multiple piezoelectric transducer units to sequentially obtain independent echo feature vectors for each sub-region of the display panel corresponding to each piezoelectric transducer unit; Based on the deviation between the independent echo feature vector of each sub-region and the corresponding reference feature vector, a two-dimensional afterimage distribution matrix is ​​constructed to mark the spatial location of the sub-regions on the display panel where particle state anomalies exist.

[0009] Optionally, the control processing unit is further configured to: Multiple ultrasonic detection excitation signals of different frequencies are output to the acoustic transducer array in a time-division manner; Echo signals at various frequencies are acquired and processed to construct a multi-frequency acoustic fingerprint containing multi-frequency response features; The multi-frequency acoustic fingerprint is matched with a pre-established acoustic fingerprint database to identify the type of afterimage in the abnormal region. The acoustic fingerprint database stores the mapping relationship between various particle anomaly causes and corresponding standard multi-frequency response modes.

[0010] Optionally, in the repair mode, the control processing unit selects a corresponding target repair strategy from a set of preset differentiated repair strategies based on the identified specific type of afterimage, in order to generate the repair driving signal; The multiple sets of differentiated repair strategies include at least one of the following: The first repair strategy is to generate a high-frequency short pulse group excitation signal to break up the particle aggregation structure. The second repair strategy is to generate a cavitation pulse group excitation signal at a target frequency to strip off the particle layer adsorbed on the wall surface. The third repair strategy is to generate a broadband sweep frequency excitation signal to enhance the mobility of the hysteresis particles. The fourth repair strategy is to generate a low-frequency modulated excitation signal to restore the uniformity of the electric field.

[0011] Optionally, after completing one ultrasonic repair excitation, the control processing unit re-executes the state detection and echo feature vector construction operation under the detection mode on the abnormal area; The newly obtained echo feature vector after repair is compared with the reference feature vector to verify the repair effect. If the deviation still exceeds the preset threshold, the parameters of the repair driving signal are adjusted and the repair excitation is applied again to form a closed-loop self-healing control.

[0012] Optionally, the control processing unit is configured to: In the repair mode, the piezoelectric transducer unit corresponding to the abnormal region and multiple piezoelectric transducers adjacent to the abnormal region work together. The electronic paper display device further includes a phase controller connected to the control processing unit. The phase controller is used to introduce a delay amount into each drive signal selected and output by the control processing unit so that the ultrasonic waves emitted by the multiple piezoelectric transducers are superimposed in phase at the spatial position of the abnormal area to form acoustic energy focusing.

[0013] Optionally, the control processing unit includes: High-voltage drive module, used for controlled output of high-voltage pulse excitation signal; A transceiver switching network is connected to the high-voltage drive module and the acoustic transducer array. The transceiver switching network is used to controllably connect the output terminals of the acoustic transducer array and the high-voltage drive module, or to controllably transmit the echo signal of the acoustic transducer array to the back end. The processing circuit, connected to the transceiver switching network and the high-voltage drive module, is used for: In detection mode, a high-voltage control signal is output to the high-voltage drive module, and a transmit / receive switching signal is output to the transmit / receive switching network to control the acoustic transducer array to perform signal transmission and reception. Multiple physical dimension feature parameters are extracted from the echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer, so as to construct an echo feature vector. The echo feature vector is compared with the reference feature vector corresponding to the no-afterimage state to determine whether there is an abnormal particle state in the currently detected area. After determining that there is an abnormal particle state, the repair mode is activated, and a repair drive signal is generated and output to the high-voltage drive module to apply ultrasonic repair excitation matching the abnormality type to the abnormal area through the high-voltage drive module and the acoustic transducer array.

[0014] Optionally, the control processing unit is configured to: The echo feature vector is compared with the reference feature vector, and a ghost image repair instruction is generated based on the deviation obtained from the comparison. The repair instruction includes the target repair type, target repair coordinates and repair excitation parameters determined according to the comparison deviation mode. According to the repair instruction, the repair mode is activated, and the repair drive signal is synthesized and output.

[0015] A second aspect of this invention provides a method for repairing image retention, applied to an electronic paper display device as described above, the method comprising: In detection mode, the acoustic transducer array is controlled to emit ultrasonic detection signals toward the microcup electrophoretic layer and receive echo signals returned from inside the microcup electrophoretic layer. Multiple physical dimension feature parameters are extracted from the received echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer, so as to construct an echo feature vector. The constructed echo feature vector is compared with the reference feature vector corresponding to the no-afterimage state to determine whether there is an abnormal particle state in the currently detected area. After determining that an anomaly exists, the repair mode is activated, and a repair drive signal is generated and output to the acoustic transducer array to apply ultrasonic repair excitation that matches the type of anomaly to the abnormal area.

[0016] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows: The above-mentioned electronic paper display device includes a display panel, an acoustic transducer array, and a control processing unit. The acoustic transducer array is integrated on the back panel side of the display panel. In the detection mode, the control processing unit drives the acoustic transducer array to emit ultrasonic detection signals and receive echo signals, extracts feature parameters from the echo signals and constructs echo feature vectors, compares the echo feature vectors with reference feature vectors, and realizes afterimage recognition and repair control operations to apply ultrasonic repair excitation matching the type of abnormality to the abnormal area. By reconstructing the acoustic transducer array into an integrated dual-function module with both active acoustic detection and repair excitation application functions, the timeliness and energy efficiency of afterimage elimination are significantly improved, while reducing the power consumption waste caused by ineffective driving and the risk of aging of the internal structure of electronic paper. Attached Figure Description

[0017] Figure 1 A schematic diagram of particles in the normal state of the microcup electrophoretic layer provided in Embodiment 1 of the present invention; Figure 2 A schematic diagram of particles in an abnormal state of a microcup electrophoretic layer provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of the display panel provided in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the control processing unit provided in Embodiment 1 of the present invention; Figure 5 A schematic diagram of the echo signals in the normal region and the afterimage region provided in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the partitioning of the display panel provided in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the structure of the piezoelectric transducer unit provided in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of a first module of the electronic paper display device provided in Embodiment 1 of the present invention; Figure 9This is a schematic diagram of a second module of the electronic paper display device provided in Embodiment 1 of the present invention; Figure 10 This is a circuit diagram of the electronic paper display device provided in Embodiment 1 of the present invention; Figure 11 This is a flowchart illustrating the afterimage repair method provided in Embodiment 2 of the present invention.

[0018] The figures in the diagram are labeled as follows: 100. Display panel; 200. Acoustic transducer array; 300. Control processing unit; 400. Array control logic; 500. Phase controller; 110. Driving layer; 120. Microcup electrophoresis layer; 121. Protective layer; 122. Transparent electrode layer; 123. Microcup array; 210. Piezoelectric transducer unit; 220. Two-dimensional switching matrix; 101. Sub-region; 310. Transceiver switching network; 320. High-voltage drive module; 330. Processing circuit; 331. Transceiver control module; 332. Signal processing module; 333. Comparison and judgment module; 334. Repair drive module; 321. Pulse generator; 322. Buffer driver; 323. High-voltage driver; 324. Power switch; 301. Charge amplifier; 302. Low-noise amplifier; 303. Bandpass filter; 304. Variable gain amplifier module; 305. Envelope detector module; 306. Signal processor; K1, first switch; K2, second switch; C1, first capacitor; C2, second capacitor; C3, third capacitor; HV, positive voltage terminal; Q1, first power switch; Q2, second power switch. Detailed Implementation

[0019] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0020] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] Example 1 Ultrasonic pulse-echo technology has been widely used in materials testing, bioimaging, and structural nondestructive testing. This technology, by analyzing the amplitude, time of flight, spectrum, and scattering characteristics of ultrasonic echoes, can achieve precise perception of the internal state of the object being tested. However, to date, no technology has been introduced into the field of electronic paper afterimage state recognition, and there is no publicly available scheme that utilizes ultrasound to simultaneously achieve both state detection and local repair functions, constructing an internal particle state perception and closed-loop self-recovery system for electronic paper.

[0023] The core of electronic paper's display is a microcup electrophoretic display architecture. The microcup is filled with positively and negatively charged electrophoretic particles and an electrophoretic liquid medium, such as... Figure 1 As shown, under normal display conditions, electrophoretic particles can migrate up and down under the drive of an electric field, thus presenting different grayscale display effects. The formation of image retention, as... Figure 2 As shown, the problem essentially stems from prolonged use or frequent local refreshes, leading to phenomena such as agglomeration, wall adsorption, charge trap accumulation, or migration lag in some electrophoretic particles, altering the particle distribution within the microcup. If low-power ultrasonic echoes can be used to actively acquire the distribution of electrophoretic particles within the microcup, establishing a correlation model between echo parameters and the degree of image retention, enabling the detection, localization, and prediction of image retention areas, and combined with local ultrasonic perturbation or other recovery mechanisms to form a closed-loop control, the ultrasound can be upgraded from a traditional repair actuator to a state-sensing unit, giving the electronic paper the ability to observe its internal state and fundamentally solving the shortcomings of existing technologies. Based on this, this invention proposes an electronic paper display device and image retention repair method, aiming to accurately identify image retention, optimize repair effects, reduce power consumption, and promote the further development of electronic paper display technology.

[0024] In this embodiment, as Figure 3 and Figure 4 As shown, the electronic paper display device includes: The display panel 100 includes a microcup electrophoresis layer 120 and a driving layer 110 for driving the microcup electrophoresis layer 120. The acoustic transducer array 200 is integrated on the back panel side of the display panel 100. The acoustic transducer array 200 is used to transmit ultrasonic detection signals to the microcup electrophoresis layer 120 and receive echo signals returned from inside the microcup electrophoresis layer 120. Control processing unit 300, used for: In detection mode, the acoustic transducer array 200 is driven to perform signal transmission and reception, and multiple physical dimension feature parameters are extracted from the echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer 120, so as to construct the echo feature vector. The echo feature vector is compared with the baseline feature vector corresponding to the state without afterimages to determine whether there is an abnormal particle state in the currently detected area. After determining that there is an abnormal particle state, the repair mode is activated, and a repair driving signal is generated and output to the acoustic transducer array 200 to apply ultrasonic repair excitation that matches the abnormality type to the abnormal area.

[0025] In this embodiment, the electronic paper display device mainly includes a display panel 100, an acoustic transducer array 200, and a control processing unit 300. The components work together to form a complete image retention recognition and self-repair system, and at the same time realize the reconstruction of the acoustic transducer array 200 from a single repair execution unit to an integrated dual-function module.

[0026] The display panel 100 is the core display component of the electronic paper display device, consisting of a microcup electrophoresis layer 120 and a driving layer 110 for driving the microcup electrophoresis layer 120. The microcup electrophoresis layer 120 adopts a microcup electrophoresis display architecture, comprising, from top to bottom, a protective layer 121, a transparent electrode layer 122, a microcup array 123, an electrophoretic medium, and electrophoretic particles. The driving layer 110 is a thin-film transistor driving layer, located below the microcup array 123. A backplate structure covers the outside of the driving layer 110, providing support and protection. The microcup array 123 consists of multiple independent microcups 1231, each microcup 1231 uniformly filled with positively and negatively charged electrophoretic particles and an electrophoretic liquid medium. Driven by an electric field, the electrophoretic particles migrate up and down along the direction of the electric field, achieving different gray levels through differences in particle distribution. Under normal display conditions, electrophoretic particles can quickly respond to changes in the electric field, complete migration, and stabilize at the target position. However, with increased usage time or frequent local refresh operations, some electrophoretic particles may exhibit phenomena such as aggregation, wall adsorption, charge trap accumulation, or migration lag. These abnormal states will change the acoustic impedance, scattering intensity, and interface reflection characteristics inside the microcup 1231, thereby forming a ghost image area.

[0027] The acoustic transducer array 200 is integrated into the back panel of the display panel 100 and is tightly bonded to the back panel via an adhesive layer. In an optional embodiment, the acoustic transducer array 200 adopts a PZT ultrasonic array structure, consisting of multiple independent piezoelectric transducer units 210, which has both ultrasonic transmission and reception functions. This eliminates the need for additional independent transmission and reception devices, effectively simplifying the system structure and reducing hardware costs. The acoustic transducer array 200 is configured to transmit ultrasonic detection signals to the microcup electrophoresis layer 120 and receive echo signals returned from inside the microcup electrophoresis layer 120. The transmission frequency of the ultrasonic detection signal can be flexibly adjusted according to detection requirements; the default initial detection frequency is 1MHz. The echo signal carries information about the distribution state of electrophoretic particles inside the microcup electrophoresis layer 120.

[0028] The control processing unit 300 is the control component of the entire electronic paper display device. It is connected to the acoustic transducer array 200 and is used to control the working mode of the acoustic transducer array 200, process echo signals, and perform afterimage recognition and repair control operations. The control processing unit 300 integrates a high-voltage drive module 320, a transceiver switching network 310, and a processing circuit 330. The processing circuit 330 can be equipped with functional units such as a transceiver control module 331, a signal processing module 332, a comparison and judgment module 333, and a repair drive module 334. These units work together to achieve orderly switching between detection mode and repair mode.

[0029] In detection mode, the transceiver control module 331 of the processing circuit 330 can control the high-voltage drive module 320 to output a high-voltage pulse excitation signal and control the transceiver switching network 310 to transmit and receive signals, thereby driving the acoustic transducer array 200 to perform the transmission of ultrasonic detection signals and the reception of echo signals. Specifically, the high-voltage drive module 320 outputs a high-voltage pulse excitation signal to the acoustic transducer array 200, driving the piezoelectric transducer unit 210 in the acoustic transducer array 200 to generate ultrasonic mechanical vibration. The ultrasonic waves pass through the drive layer 110 in the form of longitudinal waves and enter the microcup electrophoresis layer 120, where they are reflected and scattered at the microcup wall, the electrophoretic particle group, and the interfaces of each layer, forming echo signals. Figure 5 As shown, due to the different particle distribution states within the normal region and the afterimage region, their corresponding acoustic impedance, scattering intensity, and interface emission characteristics also differ, resulting in significant changes in the echo signal. The acoustic transducer array 200 converts the received echo signal into a weak charge signal and transmits it to the processing circuit 330.

[0030] The signal processing module 332 of the processing circuit 330 processes the weak charge signal and extracts feature parameters of multiple physical dimensions to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer 120, thereby constructing an echo feature vector. The echo feature vector can reflect the distribution state, migration state, and interface reflection state of electrophoretic particles inside the electronic paper from multiple dimensions, providing accurate data support for subsequent image retention recognition.

[0031] Subsequently, the comparison and judgment module 333 of the processing circuit 330 compares the constructed echo feature vector with the reference feature vector corresponding to the image-free state, and determines whether there is an abnormal particle state in the currently detected area based on the comparison result. The reference feature vector is constructed by collecting echo signals from each area in the image-free state during the factory calibration stage of the electronic paper, extracting the corresponding feature parameters, and storing it in a non-volatile memory connected to the control processing unit 300.

[0032] When the comparison and judgment module 333 determines that there is an abnormal particle state in the current detection area, the control processing unit 300 immediately starts the repair mode. The repair drive module 334 of the processing circuit 330 generates and outputs a repair drive signal to the high-voltage drive module 320 according to the abnormality type, so as to apply ultrasonic repair excitation matching the abnormality type to the abnormal area through the high-voltage drive module and the acoustic transducer array 200. Unlike the blind ultrasonic disturbance in the prior art, the ultrasonic repair excitation in this embodiment is generated based on the previously detected internal abnormality state information, which can accurately act on the abnormal area and avoid causing invalid disturbance to the normal display area.

[0033] Specifically, when comparing and determining that the peak amplitude of the echo signal decreases, the echo energy weakens, the time-of-flight shifts, or the attenuation characteristics abnormally increase, it is determined that there is a risk of ghosting or particle agglomeration anomaly in the current detection area. The repair drive module 334 outputs a high-frequency short pulse group excitation signal to disperse the agglomeration structure by enhancing particle vibration. If local interface echo enhancement is detected accompanied by time-of-flight shift, it is determined to be a wall adsorption anomaly. A cavitation pulse group excitation signal at the target frequency is output to release particle adsorption through local micro-perturbation. If the overall particle response is slow and the low-frequency energy increases, it is determined to be a migration hysteresis anomaly. A broadband sweep frequency excitation signal is output to promote the particles to regain their migration ability. When the random fluctuation of the echo signal increases and the noise floor rises, it is determined to be a charge trap ghosting. At this time, a low-frequency modulation signal with alternating polarity is output to restore the local electric field uniformity.

[0034] After the repair stimulus is applied, the control processing unit 300 will switch back to the detection mode, re-acquire the echo signal of the repair area, construct a new echo feature vector and compare it with the reference feature vector to verify the repair effect, forming a closed-loop self-healing control. When the echo feature recovers to the range of the reference feature vector, the repair is determined to be complete; if there is still an abnormality, the corresponding repair strategy will continue to be executed. By forming a closed-loop mechanism of ultrasonic detection-feature extraction-image classification-local repair-echo verification, the automatic detection and self-recovery of image retention in the electronic paper display device is realized.

[0035] Furthermore, by reconstructing the acoustic transducer array 200 into an integrated dual-function module that combines active acoustic detection and repair excitation application, a fundamental shift has been achieved from indirect inference based on visual differences or empirical thresholds to direct quantitative measurement based on internal physical state signals. This enables the detection of particle state anomalies before the afterimage appears at the visual level, significantly improving the timeliness and energy efficiency of afterimage elimination, while reducing power consumption waste caused by ineffective driving and the risk of aging of the internal structure of electronic paper.

[0036] The feature parameters can be specifically defined according to the characteristics of the microcup electrophoretic layer 120 and different afterimage states. In an optional embodiment, the feature parameters in multiple physical dimensions include at least: Peak amplitude characteristics are used to characterize the reflection intensity of the echo signal; Time-of-flight characteristics are used to characterize the time difference between the arrival time of the main reflected echo in the echo signal and the emission time of the ultrasonic detection signal, so as to reflect the position of the reflection interface inside the microcup electrophoretic layer 120. The cumulative echo energy characteristic is used to characterize the energy integral of the echo signal within a preset time window, so as to reflect the degree of aggregation of electrophoretic particles. Echo attenuation characteristics are used to characterize the amplitude attenuation relationship between echoes generated at different reflecting interfaces in the echo signal, so as to reflect the propagation loss of ultrasound in the electrophoretic particle region.

[0037] In this embodiment, the feature parameters of multiple physical dimensions include at least peak amplitude features, time-of-flight features, cumulative echo energy features, and echo attenuation features. Each feature parameter reflects the particle state inside the microcup electrophoretic layer 120 from different perspectives, complementing each other and providing a highly discriminative data foundation for the accurate identification of afterimage types.

[0038] Peak amplitude characteristics are used to characterize the reflection intensity of echo signals. The extraction process is as follows: The signal processing module 332 of the control processing unit 300 performs envelope detection processing on the received echo signal, extracts the envelope curve of the echo signal, and then uses a peak detection algorithm to filter out the maximum amplitude value from the envelope curve. This maximum amplitude value is the peak amplitude characteristic. In the normal display area, the electrophoretic particles inside the microcup are uniformly distributed, the acoustic impedance is consistent, and the reflection intensity of the echo signal is stable. However, in areas with particle anomalies, phenomena such as particle aggregation and wall adsorption change the acoustic impedance inside the microcup, causing changes in the reflection intensity of the echo signal, resulting in a significant increase or decrease in the peak amplitude characteristic. For example, in particle aggregation areas, the presence of a large number of particle aggregates leads to enhanced ultrasonic scattering, decreased reflection intensity, and a peak amplitude characteristic value lower than in normal areas. In wall adsorption-type anomaly areas, a fixed particle layer forms near the sidewall of the microcup, which enhances ultrasonic reflection, resulting in a peak amplitude characteristic value higher than in normal areas.

[0039] The time-of-flight characteristic (TOF) is used to characterize the time difference between the arrival time of the main reflected echo and the emission time of the ultrasonic detection signal, reflecting the position of the reflection interface inside the microcup electrophoretic layer 120. The extraction process is as follows: the signal processing module 332 records the emission time of the ultrasonic detection signal and simultaneously monitors the reception status of the echo signal. When the peak value of the main reflected echo is detected, the arrival time of that peak value is recorded. The difference between the two times is the TOF. Under normal display conditions, the electrophoretic particles inside the microcup are evenly distributed, and the reflection interfaces are mainly at the bottom and top of the microcup, with the TOF value remaining stable within a fixed range. When particle anomalies occur, the position of the reflection interface shifts, causing deviations in the TOF value. For example, in wall-adsorption type anomaly areas, particles adsorb onto the sidewall of the microcup, forming new reflection interfaces and shortening the TOF value; in migration hysteresis type anomaly areas, particles cannot migrate normally to the target position, causing the reflection interface position to shift downwards and prolonging the TOF value.

[0040] The cumulative echo energy characteristic is used to characterize the energy integral of the echo signal within a preset time window, reflecting the degree of aggregation of electrophoretic particles. The preset time window is set to match the frequency of the ultrasonic detection signal and the thickness of the electronic paper, ensuring coverage of all valid echo signals. The signal processing module 332 performs integration calculations on the echo signals within the preset time window, and the result is the cumulative echo energy characteristic. The higher the degree of aggregation of electrophoretic particles, the greater the scattering loss of ultrasound during propagation, the weaker the energy of the echo signal, and the lower the cumulative echo energy characteristic value. Therefore, by observing the changes in the cumulative echo energy characteristic, the aggregation state of electrophoretic particles inside the microcup can be directly reflected, providing a key basis for the identification of particle aggregation anomalies.

[0041] Echo attenuation characteristics are used to characterize the amplitude attenuation relationship between echoes generated by different reflecting interfaces in the echo signal, reflecting the propagation loss of ultrasound in the electrophoretic particle region. The extraction process is as follows: the signal processing module 332 identifies the echo peaks generated by different reflecting interfaces in the echo signal, calculates the ratio of the amplitude difference between two adjacent echo peaks to the previous echo peak, and this ratio is the echo attenuation characteristic. In the normal display area, the propagation loss of ultrasound in the electrophoretic particle region is stable, and the echo attenuation characteristic value remains within a fixed range. When particle anomalies occur, the propagation loss changes, and the echo attenuation characteristic value becomes abnormal. For example, in the migration hysteresis anomaly region, the particle migration ability decreases, leading to an increase in the propagation loss of ultrasound and an increase in the echo attenuation characteristic value; in the charge trap anomaly region, the charge traps accumulated inside the electronic paper affect the charged state of the electrophoretic particles, causing random fluctuations in the echo signal, and the echo attenuation characteristic value also shows irregular changes.

[0042] By extracting the characteristic parameters that are differently affected by the four physical processes of particle aggregation state, wall adsorption state, and migration lag state, respectively, an echo feature vector is constructed: F

[0043] in, Indicates the peak amplitude characteristics of the echo. Indicates the time-of-flight characteristics of ultrasound. Indicates the characteristics of echo energy. This indicates the echo attenuation characteristics. These characteristics can reflect the distribution, migration, and interface reflection states of electrophoretic particles inside the electronic paper display device from different dimensions.

[0044] The constructed echo feature vector can reflect the distribution, migration, and interface reflection states of electrophoretic particles inside the electronic paper display device from different dimensions. This solves the problem that existing technologies rely on a single-dimensional echo indicator with limited information and cannot effectively distinguish abnormal particle states caused by different physical factors, significantly reducing the false judgment rate of afterimage recognition. Simultaneously, the control processing unit 300 can normalize each feature parameter, unifying the value range of each feature parameter to between 0 and 1. This avoids the impact of differences in the dimensions of the feature parameters on the comparison effect between the echo feature vector and the reference feature vector, further improving the accuracy of the comparison.

[0045] In order to achieve precise spatial positioning and restoration of the afterimage area, in one optional embodiment, such as Figure 6 and Figure 7 As shown, the acoustic transducer array 200 includes multiple piezoelectric transducer units 210; The control processing unit 300 is also used for: Addressing scans are performed on multiple piezoelectric transducer units 210 to sequentially obtain the independent echo feature vector of the sub-region 101 of the display panel 100 corresponding to each piezoelectric transducer unit 210; Based on the deviation between the independent echo feature vector of each sub-region 101 and the corresponding reference feature vector, a two-dimensional afterimage distribution matrix is ​​constructed to mark the spatial location of the sub-region 101 in the display panel 100 where there is an abnormal particle state.

[0046] In this embodiment, the acoustic transducer array 200 includes multiple independent piezoelectric transducer units 210, which are arranged in an array. The arrangement can be flexibly adjusted according to the size of the electronic paper. Common arrangements are grid-like arrangements of 16×16, 32×32 or 64×64, ensuring that each piezoelectric transducer unit 210 corresponds to an independent sub-region 101 in the electronic paper display area.

[0047] The control processing unit 300 is configured to perform addressing scans on multiple independent piezoelectric transducer units 210 to sequentially acquire the independent echo feature vector of the sub-region 101 corresponding to each piezoelectric transducer unit 210. During the addressing scan, the control processing unit 300 sends an address signal to the acoustic transducer array 200 through the array control logic 400 to select the target piezoelectric transducer unit 210, while placing all other piezoelectric transducer units 210 in a high-impedance isolation state to avoid signal crosstalk. The scanning order can be selected as row scanning, column scanning, or block scanning according to actual needs. In an optional embodiment, row scanning is used. The control processing unit 300 first scans all sub-regions 101 in the first row, then scans the second row, and so on, until the echo acquisition and feature vector construction of the entire display panel 100 are completed.

[0048] During the scanning process, each piezoelectric transducer 210 and its corresponding sub-region 101 acquires an independent echo feature vector. The control processing unit 300 compares the independent echo feature vector of each sub-region 101 with the reference feature vector of the corresponding sub-region 101 and calculates the deviation of each feature parameter. If the deviation of the echo feature vector of a certain sub-region 101 from the reference feature vector exceeds a preset threshold, it is determined that there is a particle state anomaly in that sub-region 101. Subsequently, based on the anomaly determination results of each sub-region 101, the control processing unit 300 constructs a two-dimensional afterimage distribution matrix to mark the spatial location of the sub-region 101 with the particle state anomaly.

[0049] The two-dimensional afterimage distribution matrix is ​​a two-dimensional matrix structure. Each coordinate point in the matrix corresponds to an actual detection sub-region 101 on the display panel 100. The value represents the degree of abnormality of the sub-region 101; the larger the value, the more severe the particle state abnormality of the sub-region 101. Specifically, the control processing unit 300 quantizes the deviation of each sub-region 101, fills the quantized value into the corresponding coordinate position of the two-dimensional afterimage distribution matrix, and marks the sub-regions 101 with abnormalities, forming a clear spatial distribution map of afterimage regions. For example, if the quantized deviation value of a certain sub-region 101 is 85, exceeding the preset threshold of 60, then the sub-region 101 is determined to be abnormal, and is marked as 85 at the corresponding position in the two-dimensional afterimage distribution matrix, intuitively reflecting the severity of the abnormality in that region.

[0050] By constructing an array addressing scan and a two-dimensional afterimage distribution matrix, the control processing unit 300 achieves precise spatial positioning of the afterimage area, solving the problems of existing technologies that cannot identify local afterimages on the whole screen and can only perform indiscriminate global refresh, resulting in long repair time, high power consumption, and unnecessary disturbance to the normal display area.

[0051] Furthermore, by precisely narrowing the target area for repair from the entire screen to the coordinates of the lesion, direct coordinates and boundary information are provided for subsequent detailed local repair. This also allows staff to intuitively understand the particle state distribution on the display panel 100, providing data support for subsequent maintenance and optimization. In addition, the control processing unit 300 updates the two-dimensional afterimage distribution matrix in real time. After each detection, the matrix data is updated based on the new detection results to ensure the timeliness and accuracy of afterimage area positioning.

[0052] Different types of afterimages respond differently to ultrasonic waves of different frequencies. For example, particle agglomeration regions contain a large number of particle aggregates, making high-frequency ultrasound more prone to scattering and attenuation during propagation, resulting in a significant decrease in echo energy above 1.5 MHz. Wall-adsorption type afterimages mainly manifest as a fixed particle layer forming near the sidewall of the microcup, and are more sensitive to mid-frequency ultrasound reflection. Migration-hysteresis type afterimages are more characterized by changes in overall fluid damping, which have a more significant impact on the propagation characteristics of low-frequency ultrasound. Therefore, relying solely on a single frequency echo is insufficient to accurately distinguish the causes of afterimages, while multi-frequency detection can generate a more discernible set of features.

[0053] Therefore, in an optional embodiment, the control processing unit 300 is further configured to: Multiple ultrasonic detection excitation signals of different frequencies are output to the acoustic transducer array at 200 minutes. Echo signals at various frequencies are acquired and processed to construct a multi-frequency acoustic fingerprint containing multi-frequency response features; Multi-frequency acoustic fingerprints are matched with a pre-established acoustic fingerprint database to identify the type of afterimage in abnormal regions. The acoustic fingerprint database stores the mapping relationship between various particle anomaly causes and corresponding standard multi-frequency response modes.

[0054] In this embodiment, the control processing unit 300 is configured to output multiple ultrasonic detection excitation signals of different frequencies to the acoustic transducer array 200 in a time division manner. Common detection frequencies include 500kHz, 1MHz, 1.5MHz and 2MHz. The ultrasonic detection excitation signals of each frequency are transmitted sequentially at a preset interval, for example, the transmission interval is 50ms, to avoid mutual interference between ultrasonic signals of different frequencies.

[0055] The control processing unit 300 sequentially drives the acoustic transducer array 200 to emit ultrasonic detection excitation signals of different frequencies according to a preset timing sequence. After each frequency of ultrasonic wave enters the microcup electrophoresis layer 120, it forms a corresponding echo, which is received by the acoustic transducer array 200 and converted into a weak charge signal before being transmitted to the control processing unit 300. The signal processing module 332 of the control processing unit 300 processes the echo signals at each frequency separately, extracting the peak amplitude characteristics, time-of-flight characteristics, cumulative echo energy characteristics, and echo attenuation characteristics at each frequency, thereby constructing a multi-frequency acoustic fingerprint containing multi-frequency response characteristics.

[0056] Multi-frequency acoustic fingerprints are multi-dimensional feature vector structures that contain the values ​​of various feature parameters at different frequencies, reflecting the comprehensive response of the particle distribution state inside the electronic paper to ultrasound at different frequencies. Different types of afterimages respond differently to ultrasound at different frequencies, which is the core basis for constructing multi-frequency acoustic fingerprints to achieve accurate afterimage type identification. For example, in particle agglomeration regions, there are a large number of particle aggregates, and high-frequency ultrasound is more easily scattered and attenuated during propagation, resulting in a significant decrease in echo energy above 1.5MHz; wall adsorption type afterimages mainly manifest as a fixed particle layer forming near the sidewall of the microcup, which is more sensitive to mid-frequency ultrasound reflection, and the echo peak value in the 1MHz to 1.5MHz frequency band will be significantly enhanced; migration hysteresis type afterimages are more manifested as changes in overall fluid damping, which have a more significant impact on the propagation characteristics of low-frequency ultrasound, and the echo tail in the frequency band below 500kHz will increase; charge trap type afterimages will cause random fluctuations in echoes in all frequency bands, accompanied by an increase in noise floor.

[0057] The control processing unit 300 matches the constructed multi-frequency acoustic fingerprint with a pre-established acoustic fingerprint database to identify the specific type of afterimage in the abnormal region. The acoustic fingerprint database stores the mapping relationship between various particle anomaly causes and corresponding standard multi-frequency response modes, and is stored in a non-volatile memory connected to the control processing unit 300. Each standard mode in the acoustic fingerprint database is a multi-dimensional feature vector matrix constructed based on the peak amplitude variation, spectral energy distribution, echo attenuation rate, and phase change characteristics of samples of different regions and different afterimage causes collected at multiple different frequencies during the factory calibration stage of the electronic paper display device.

[0058] During the matching process, the control processing unit 300 uses a similarity algorithm to calculate the similarity between the real-time multi-frequency acoustic fingerprint and each standard multi-frequency response pattern in the acoustic fingerprint database. The ghosting type corresponding to the standard pattern with the highest similarity is the specific ghosting type of the current abnormal region.

[0059] When the echo energy in the high-frequency band decreases significantly while the low-frequency band changes little, the control processing unit 300 determines it to be a particle agglomeration type of afterimage; when the mid-frequency reflection peak increases and is accompanied by a local time-of-flight shift, the control processing unit 300 determines it to be a wall adsorption type of afterimage; when the low-frequency echo tail increases and the overall response is delayed, the control processing unit 300 determines it to be a migration hysteresis type of afterimage; when the echoes in each frequency band exhibit random fluctuations and are accompanied by a rise in the noise floor, the control processing unit 300 determines it to be a charge trap type of afterimage.

[0060] If the similarity is lower than the preset threshold, the type of afterimage in the current abnormal area is determined to be unknown. The control processing unit 300 will issue an alarm signal and record the multi-frequency acoustic fingerprint of the area to facilitate subsequent supplementation and optimization of the acoustic fingerprint database.

[0061] This embodiment solves the problem of overlapping acoustic features of different afterimage causes under single-frequency detection, which makes it impossible to effectively distinguish specific afterimages, by matching multi-frequency acoustic fingerprints with an acoustic fingerprint database. It achieves accurate classification of afterimage types, providing the most critical information for subsequent repair strategies, effectively avoiding feature overlap between different afterimages and improving classification accuracy.

[0062] Correspondingly, when the type of afterimage is determined, different repair strategies and different excitation signals can be selected. In an optional embodiment, the control processing unit 300, in the repair mode, selects a set of corresponding target repair strategies from a set of preset differentiated repair strategies based on the identified specific type of afterimage, so as to generate a repair driving signal. Among them, the multiple sets of differentiated repair strategies include at least one of the following: The first repair strategy is to generate a high-frequency short pulse group excitation signal to break up the particle aggregation structure. The second repair strategy is to generate a cavitation pulse group excitation signal at a target frequency to strip off the particle layer adsorbed on the wall surface. The third repair strategy is to generate a broadband sweep frequency excitation signal to enhance the mobility of the hysteresis particles. The fourth repair strategy is to generate a low-frequency modulated excitation signal to restore the uniformity of the electric field.

[0063] In this embodiment, in the repair mode, the control processing unit 300 selects a corresponding target repair strategy from a set of preset differentiated repair strategies based on the specific type of the identified afterimage, so as to generate a repair driving signal and drive the acoustic transducer array 200 to apply ultrasonic repair excitation.

[0064] Multiple preset differentiated repair strategies are stored in the storage module of the control processing unit 300, including at least a first repair strategy, a second repair strategy, a third repair strategy, and a fourth repair strategy. Each repair strategy corresponds to a different type of afterimage, and the parameters of its repair driving signal are significantly different to ensure the targeted nature of the repair effect.

[0065] The first repair strategy corresponds to particle clustering afterimages. Its core is to generate a high-frequency short pulse group excitation signal to break up the particle cluster structure. The frequency of the high-frequency short pulse group excitation signal can be set to 1.0MHz to 2MHz, the pulse width to 10μs to 20μs, and the peak-to-peak voltage to 30V to 60V. Through the shear force generated by high-frequency mechanical vibration, the adsorption force between particles is broken up, and the migration ability of the particles is reactivated.

[0066] The second repair strategy addresses wall-adsorption-type residual images. Its core is generating a cavitation pulse group excitation signal at a target frequency to strip away the particle layer adsorbed on the wall. The frequency of the cavitation pulse group excitation signal can be set to 300kHz-800kHz, with a period of 5ms to 10ms and a peak-to-peak voltage of 40V to 80V. This frequency range can generate a cavitation effect in the electrophoretic liquid medium inside the microcup, forming tiny cavitation bubbles. When these cavitation bubbles burst, they generate local high pressure and microjets, which act on the particle layer adsorbed on the microcup sidewall, releasing the adsorption relationship between the particles and the sidewall, allowing the particles to redisperse in the electrophoretic liquid medium. Simultaneously, the control processing unit 300 adjusts the amplitude and excitation time of the cavitation pulse group excitation signal according to the severity of wall adsorption; the higher the adsorption severity, the larger the excitation amplitude and the longer the excitation time.

[0067] The third repair strategy corresponds to the hysteresis-type afterimage. Its core is to generate a broadband swept-frequency excitation signal to enhance the mobility of the hysteresis particles. The broadband swept-frequency excitation signal has a sweep frequency range of 200kHz to 2MHz, a sweep period of 500ms, and a peak-to-peak voltage of 30V to 60V. By applying ultrasonic excitation at different frequencies to the hysteresis particles, the steady state of the particles is disrupted, promoting the particles to regain their mobility and restore their response to the electric field.

[0068] The fourth repair strategy corresponds to charge trap type afterimages. The control processing unit 300 will generate a low-frequency modulation excitation signal with alternating polarity. The frequency can be set to 500Hz or below, the duty cycle is 50%, the period is 2s-5s, and the peak-to-peak voltage is 50V to 80V. Combined with the alternating change of electric field polarity, the uniformity of the local electric field is restored, and the accumulation of charge traps is eliminated.

[0069] By directly binding the identified cause type of afterimage to the physical action mode of the repair signal, the control processing unit 300 can avoid using ineffective repair methods that cannot eradicate specific afterimages. This solves the problem that existing ultrasonic repair methods, which cannot determine the cause, can only use a single, indiscriminate perturbation mode, resulting in low repair efficiency or repair failure.

[0070] Meanwhile, the control processing unit 300 controls the acoustic transducer array 200 to apply ultrasonic repair excitation only to the abnormal area based on the location of the abnormal area marked by the two-dimensional afterimage distribution matrix, so as to avoid disturbing the normal display area, further improve the repair efficiency and reduce the repair power consumption.

[0071] In order to achieve closed-loop self-repair, in an optional embodiment, the control processing unit 300, after completing one ultrasonic repair excitation, re-executes the state detection and echo feature vector construction operation in the detection mode on the abnormal area. The newly obtained echo feature vector after repair is compared with the reference feature vector to verify the repair effect. If the deviation still exceeds the preset threshold, the parameters of the repair driving signal are adjusted and the repair excitation is applied again to form a closed-loop self-healing control.

[0072] In this embodiment, after the control processing unit 300 completes the application of an ultrasonic repair excitation, it immediately re-executes the state detection and echo feature vector construction operation in the detection mode on the abnormal area. Through the same set of acoustic transducer array 200 and its subsequent signal processing links, it is reused as the judge unit for the verification of the repair effect, forming a closed-loop control path of detection-repair-verification.

[0073] Specifically, after applying the ultrasonic repair excitation, the control and processing unit 300 immediately switches to detection mode, drives the acoustic transducer array 200 to emit ultrasonic detection signals to the repaired abnormal area, receives and processes the echo signals, extracts multi-dimensional feature parameters, and constructs a new echo feature vector after repair. Subsequently, the control and processing unit 300 performs a second comparison between the new echo feature vector obtained after repair and the reference feature vector, calculates the deviation of each feature parameter, and verifies the repair effect based on the deviation. If the deviation does not exceed a preset threshold, it indicates that the repair effect meets the standard, and the repair is judged to be successful. The control and processing unit 300 records the repair completion information, including the repair area, afterimage type, repair parameters, repair time, etc., for subsequent traceability and optimization.

[0074] If the deviation still exceeds the preset threshold, it indicates insufficient repair. The control processing unit 300 will adjust the parameters of the repair drive signal and apply the repair excitation again. The parameter adjustment is based on the deviation pattern between the new echo characteristic vector and the reference characteristic vector. For example, if the peak amplitude characteristic is still lower than the reference value, it indicates that the particle aggregation or wall adsorption problem has not been completely resolved. The control processing unit 300 will appropriately increase the amplitude and excitation time of the high-frequency short pulse group excitation signal or cavitation pulse group excitation signal. If the time-of-flight characteristic still has a deviation, it indicates that the particle migration ability has not been fully restored. The control processing unit 300 will adjust the sweep range and sweep period of the broadband sweep excitation signal. After the adjustment is completed, the control processing unit 300 applies the ultrasonic repair excitation again and repeats the above verification process until the deviation between the repaired echo characteristic vector and the reference characteristic vector exceeds the preset threshold.

[0075] If the deviation still fails to meet the preset requirements after multiple adjustments of parameters and application of repair stimuli, the control processing unit 300 determines that there is a hardware fault in the abnormal area, such as microcup breakage or electrophoresis liquid medium leakage. At this time, the control processing unit 300 will issue an alarm signal to remind the staff to carry out maintenance, so as to avoid power waste and damage to the internal structure of electronic paper caused by ineffective repair.

[0076] By adopting a closed-loop self-healing control mechanism, the problem of lack of real-time feedback in existing open-loop repair schemes, which cannot ensure that the particle anomaly has been completely resolved in this round of repair, is solved. This avoids repeated ghosting caused by insufficient repair, as well as the waste of normal pixels and system energy caused by over-repair, and ensures high reliability and automation of the repair process.

[0077] Furthermore, to avoid the problem of repair energy being spatially dispersed and causing sidelobe interference to the normal region, in an optional embodiment, the control processing unit 300 is used to: In the repair mode, the piezoelectric transducer 210 corresponding to the abnormal area and multiple piezoelectric transducers 210 adjacent to the abnormal area work together. like Figure 8 As shown, the electronic paper display device also includes a phase controller 500, which is connected to the control processing unit 300. The phase controller 500 is used to introduce a delay amount into the drive signals selected and output by the control processing unit 300, so that the ultrasonic waves emitted by the multiple piezoelectric transducers 210 are superimposed in phase at the spatial position of the abnormal area to form sound energy focusing.

[0078] In this embodiment, in the repair mode, the control processing unit 300 controls the piezoelectric transducer 210 corresponding to the abnormal area and multiple piezoelectric transducers 210 adjacent to the abnormal area to work together. By configuring the phase controller 500, an independent delay is introduced for each selected drive signal, so that the ultrasonic wavefronts emitted by multiple piezoelectric transducers 210 are superimposed in phase at the spatial position of the abnormal area to form acoustic energy focusing.

[0079] Specifically, the control processing unit 300 first determines the piezoelectric transducer 210 corresponding to the target abnormal region and the adjacent piezoelectric transducer 210 that need to work together, based on the location of the abnormal region marked by the two-dimensional afterimage distribution matrix. The number of adjacent piezoelectric transducer 210 is flexibly adjusted according to the size of the abnormal region, usually from 3 to 8. Subsequently, the control processing unit 300 sends an address signal to the array control logic 400 to select the target piezoelectric transducer 210 and the adjacent piezoelectric transducer 210, while placing the other piezoelectric transducer 210 in a high-impedance isolation state.

[0080] The electronic paper display device also includes array control logic 400, which can be a decoder, controller, etc. Array control logic 400 receives the address signal output by the control processing unit 300 and outputs a corresponding drive signal to the corresponding high-voltage analog switch in the two-dimensional switch matrix 220. Each high-voltage analog switch is connected to and controls an independent piezoelectric transducer unit 210. A phase controller 500 is cascaded between the array control logic 400 and the drive channel of the two-dimensional switch matrix 220, used to configure independent delay amounts for each selected drive signal. The delay amount is calculated based on the distance between each piezoelectric transducer unit 210 and the target abnormal region; the greater the distance, the greater the delay amount, ensuring that the ultrasonic waves emitted by each piezoelectric transducer unit 210 can reach the target abnormal region simultaneously, achieving wavefront in-phase superposition. For example, if the distance between a certain adjacent piezoelectric transducer 210 and the target abnormal area is 0.5 mm farther than the target piezoelectric transducer 210, and the propagation speed of ultrasound in the electrophoretic liquid medium is 1500 m / s, then the delay of the driving signal of the adjacent piezoelectric transducer 210 is 0.5 mm / 1500 m / s ≈ 0.33 μs.

[0081] Through precise delay control by the phase controller 500, the ultrasonic waves emitted by multiple piezoelectric transducers 210 form a focused ultrasonic beam in the target anomalous area. The energy density of the focused ultrasonic beam is several times that of ordinary ultrasonic excitation, which can more effectively handle stubborn particle agglomeration or wall adsorption. At the same time, because the acoustic energy is concentrated in the target anomalous area, it can minimize interference with the particle state inside the microcup in the adjacent non-anomalous area, and avoid the appearance of new particle anomalies in the normal display area.

[0082] By employing acoustic energy focusing technology, the problem of spatial dispersion of repair energy and sidelobe interference in normal areas when directly driving a single or entire transducer unit is solved, significantly improving the repair effect without increasing the overall transmission power.

[0083] The acoustic transducer array 200 may further include a two-dimensional switch matrix 220, where each intersection of the two-dimensional switch matrix 220 is a high-voltage analog switch, and each high-voltage analog switch is connected to and controls an independent piezoelectric transducer unit 210. The high-voltage analog switches can be fabricated using high-voltage switching transistors, which have the characteristics of high withstand voltage, low on-resistance, and fast response speed, and can meet the control requirements of ultrasonic transmission and reception.

[0084] The two-dimensional switch matrix 220 adopts a row-column addressing structure, including multiple row control lines and multiple column control lines. The intersection of the row control lines and column control lines connects to high-voltage analog switches, and the output terminal of each high-voltage analog switch is connected to a piezoelectric transducer unit 210. In detection mode or repair mode, the control processing unit 300 sends an address signal to an array control logic 400 to control the high-voltage analog switches in the corresponding rows and columns of the two-dimensional switch matrix 220 to conduct, select a unique target piezoelectric transducer unit 210, and place all other piezoelectric transducer units 210 in a high-impedance isolation state.

[0085] Specifically, after receiving the address signal sent by the control processing unit 300, the array control logic 400 decodes the address signal to generate row control signals and column control signals. The row control signals are used to control the on and off of the high-voltage analog switches in the corresponding row, and the column control signals are used to control the on and off of the high-voltage analog switches in the corresponding column. When the high-voltage analog switches in a certain row and a certain column are simultaneously turned on, the corresponding piezoelectric transducer unit 210 is selected and establishes a connection with the high-voltage drive module 320 or the signal processing module 332; the high-voltage analog switches in other rows and columns are all in the off state, and the corresponding piezoelectric transducer units 210 are placed in a high-impedance isolation state to avoid signal crosstalk.

[0086] By employing a two-dimensional cross-point switch matrix based on address decoding to manage multiple piezoelectric transducer units 210 in the array, time-division multiplexing connection of a single common transceiver bus to any transducer unit is achieved. This solves the problem of massive hardware scale, drastically increased system complexity and cost caused by configuring a complete high-voltage transmitting module and low-noise receiving front-end for each independent transducer unit in the array. Simultaneously, strictly placing non-working units in a high-impedance isolation state effectively avoids crosstalk between channels, ensuring the signal-to-noise ratio and purity of the echo signal during single-point detection. Furthermore, the two-dimensional switch matrix 220 has a simple structure, is easy to control, and can adapt to different numbers of piezoelectric transducer units 210, possessing good compatibility and scalability.

[0087] In repair mode, the control processing unit 300 controls the two-dimensional switch matrix 220 to synchronously select a group of adjacent transducer units centered on the piezoelectric transducer unit 210 in the target abnormal area. At the same time, the phase controller 500, which is cascaded between the array control logic 400 and the drive channel of the two-dimensional switch matrix 220, configures an independent delay for the drive signal of each unit in the group of adjacent transducer units.

[0088] The control processing unit 300 first determines the location of the target abnormal region based on the two-dimensional afterimage distribution matrix, calculates the number and location of adjacent transducer units to be selected, and sends a control signal containing the addresses of the target transducer unit and adjacent transducer units to the array control logic 400. The array control logic 400 decodes the control signal, generates multiple row control signals and column control signals, controls the high-voltage analog switches in the corresponding rows and columns of the two-dimensional switch matrix 220 to conduct synchronously, selects the target transducer unit and adjacent transducer units, and establishes a connection between these transducer units and the high-voltage drive module 320.

[0089] The phase controller 500 receives the delay control signal sent by the control processing unit 300 and configures an independent delay amount for each drive signal based on the distance between each selected transducer unit and the target anomalous region. The delay control signal contains the delay parameters of each selected transducer unit. After the phase controller 500 performs delay processing on each drive signal according to the delay parameters, it transmits the signal to the drive channel of the two-dimensional switch matrix 220 to drive the corresponding piezoelectric transducer unit 210 to emit ultrasonic waves. Through precise delay control, the ultrasonic waves emitted by each selected transducer unit achieve wavefront in-phase superposition in the target anomalous region, forming acoustic energy focusing.

[0090] In detection mode, the control processing unit 300 controls the two-dimensional switch matrix 220 through the array control logic 400 to sequentially select individual piezoelectric transducer units 210 for addressing and scanning. At this time, the phase controller 500 is in a sleep state and does not participate in signal processing. When it is necessary to switch to the repair mode and focus acoustic energy, the control processing unit 300 wakes up the phase controller 500 and simultaneously controls the two-dimensional switch matrix 220 to synchronously select multiple transducer units, realizing the coordinated operation of the two.

[0091] By cascading the phase control function after the array gating logic, it is possible to directly call the same set of switch matrix hardware for multi-point synchronous driving and apply precise phase control, while maintaining the original scanning and detection function that relies solely on single-point addressing via the switch matrix. This achieves hardware reuse for both detection and focusing / repair modes. It solves the problem of needing to add a separate multi-channel excitation array and synchronous control system for acoustic energy focusing / repair, achieving high-precision localized energy delivery while minimizing hardware expansion costs and system control complexity.

[0092] The pre-established acoustic fingerprint database can be stored in a non-volatile memory connected to the control processing unit 300. The non-volatile memory uses flash memory chips, which have the characteristics of large storage capacity, fast read and write speed, and no data loss when power is off, and can meet the storage requirements of the acoustic fingerprint database.

[0093] The standard patterns in the acoustic fingerprint database are multi-dimensional feature vector matrices constructed based on the peak amplitude variation, spectral energy distribution, echo attenuation rate, and phase change characteristics of samples from different regions and different types of afterimage formation at multiple different frequencies during the factory calibration stage of electronic paper display devices.

[0094] The specific operation process of the factory calibration stage is as follows: First, select multiple electronic paper display devices of the same model as calibration samples to simulate different particle abnormal states, including particle aggregation type, wall adsorption type, migration lag type, charge trap type, etc. Set different severity levels for each abnormal state to ensure the diversity of calibration samples.

[0095] Subsequently, ultrasonic detection signals at multiple frequencies (500 kHz, 1 MHz, 1.5 MHz, and 2 MHz) were emitted to different regions of each calibration sample. Echo signals at each frequency were acquired, and peak amplitude variation, spectral energy distribution, echo attenuation rate, and phase change characteristics were extracted to construct a multi-dimensional feature vector. For calibration samples without afterimages, echo signals at different regions and frequencies were also acquired to construct a standard multi-frequency response pattern for the afterimage-free state, serving as a baseline feature. The constructed multi-dimensional feature vectors for different afterimage causes and severity levels were then processed, normalized, and stored in non-volatile memory to form an acoustic fingerprint database.

[0096] To improve the versatility and robustness of the acoustic fingerprint database, the factory calibration stage also considers factors such as differences in production processes and material batch fluctuations, selecting electronic paper display devices from different batches as calibration samples to ensure that the acoustic fingerprint database can be adapted to different batches of products.

[0097] Meanwhile, the acoustic fingerprint database has an expandable function. The control processing unit 300 can record multi-frequency acoustic fingerprints of unknown types of afterimages encountered during actual detection. Staff can use special debugging tools to supplement these unknown types of multi-frequency acoustic fingerprints into the acoustic fingerprint database, continuously improve the content of the acoustic fingerprint database, and improve the accuracy of afterimage type recognition.

[0098] By modeling and storing the responses of various known ghosting causes at different frequencies based on the specific physical structure and material characteristics of the equipment during the factory calibration phase, a dedicated fingerprint reference standard was established. This solves the problem of model mismatch and decreased classification accuracy that may occur when using a general model to match the real-time echo characteristics of the target machine during on-site testing due to differences in production processes or material batch fluctuations. Using a pre-established dedicated benchmark database as the basis for judgment ensures high accuracy in ghosting type classification and robust consistency across devices.

[0099] The control processing unit 300 can employ corresponding control modules, switch switching modules, etc., such as Figure 4 and Figure 9 As shown, in an optional embodiment, the control processing unit 300 includes: High-voltage drive module 320 is used for controlled output of high-voltage pulse excitation signal; The transceiver switching network 310 is connected to the high-voltage drive module 320 and the acoustic transducer array 200. The transceiver switching network 310 is used to controllably connect the output terminals of the acoustic transducer array 200 and the high-voltage drive module 320, or to controllably transmit the echo signal of the acoustic transducer array 200 to the back end. Processing circuit 330, connected to transceiver switching network 310 and high-voltage drive module 320, is used for: In detection mode, a high-voltage control signal is output to the high-voltage drive module 320, and a transmit / receive switching signal is output to the transmit / receive switching network 310 to control the acoustic transducer array 200 to perform signal transmission and reception. Feature parameters of multiple physical dimensions are extracted from the echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer 120, so as to construct the echo feature vector. The echo feature vector is compared with the baseline feature vector corresponding to the state without afterimages to determine whether there is an abnormal particle state in the currently detected area. After determining that there is an abnormal particle state, the repair mode is activated, and a repair drive signal is generated and output to the high-voltage drive module 320 to apply ultrasonic repair excitation matching the abnormality type to the abnormal area through the high-voltage drive module 320 and the acoustic transducer array 200.

[0100] In this embodiment, the control processing unit 300 includes a high-voltage drive module 320, a transceiver switching network 310, and a processing circuit 330, such as... Figure 9 As shown, the processing circuit 330 can be equipped with functional units such as a transceiver control module 331, a signal processing module 332, a comparison and judgment module 333, and a repair drive module 334. Each unit works in concert to achieve orderly switching between detection mode and repair mode.

[0101] The transceiver control module 331 is used to control the switching state of the transceiver switching network 310. The transceiver switching network 310 is constructed using a high-speed analog switch, which has the characteristics of fast switching speed and high isolation, and can meet the requirements of ultrasonic transceiver switching.

[0102] In an alternative embodiment, such as Figure 10 As shown, the transmit / receive switching network 310 includes a first switch K1, a second switch K2, and a second capacitor C2. The first switch K1 constitutes a transmit switch, and the second switch K2 constitutes a receive switch. The first switch K1 and the second switch K2 are connected to the output terminal of the high-voltage drive module 320. When the first switch K1 is turned on, it connects the acoustic transducer array 200 and the output terminal of the high-voltage drive module 320. When the second switch K2 is turned on, it connects the acoustic transducer array 200 and the input terminal of the signal processing module 332. During the transmission period of the ultrasonic detection signal, the transceiver control module 331 sends a control signal to the transceiver switching network 310, controlling the transceiver switching network 310 to connect the acoustic transducer array 200 to the output terminal of a high-voltage drive module 320 and disconnect it from the signal processing module 332. At this time, the high-voltage pulse excitation signal output by the high-voltage drive module 320 is transmitted to the acoustic transducer array 200 through the transceiver switching network 310, driving the acoustic transducer array 200 to transmit the ultrasonic detection signal. The duration of the transmission period is determined according to the pulse width and frequency of the ultrasonic detection signal to ensure that the ultrasonic detection signal can be transmitted completely.

[0103] During the reception period for the echo signal, the transceiver control module 331 sends a control signal to the transceiver switching network 310, controlling the transceiver switching network 310 to connect the acoustic transducer array 200 to the input terminal of the signal processing module 332 and disconnect it from the high-voltage drive module 320. At this time, the echo signal received by the acoustic transducer array 200 is converted into a weak charge signal and transmitted to the signal processing module 332 through the transceiver switching network 310 for subsequent signal processing. The duration of the reception period is determined based on the propagation distance of the ultrasonic detection signal and the thickness of the electronic paper to ensure coverage of all valid echo signals.

[0104] The transceiver control module 331 achieves time-division duplex operation by precisely controlling the switching between the transmission and reception periods, thus preventing the high-voltage pulse signal from the high-voltage drive module 320 from damaging the signal processing module 332. At the same time, it effectively isolates the residual noise of the transmission path from affecting the weak received signal, ensuring the signal-to-noise ratio of the echo signal acquisition.

[0105] By setting up a high-speed switching transceiver network 310 at the physical link layer and making the control processing unit 300 strictly follow the time-division duplex transmission and reception periods for logical control, safe multiplexing of two functions—high-voltage high-power signal transmission and weak charge signal reception—is achieved on the same physical connection channel. This solves the problem that directly connecting high-energy transmission circuits and high-sensitivity receiving circuits in parallel on the same piezoelectric transducer can lead to damage to the receiving front end due to high-voltage pulse breakdown.

[0106] In an optional embodiment, the high-voltage drive module 320 includes a pulse generator 321, a buffer driver 322, a high-voltage driver 323, and a power switch 324 connected in sequence. The power switch 324 includes a first power switch Q1 and a second power switch Q2 connected in series between the positive voltage terminal HV and the ground terminal. The connection node of the first power switch Q1 and the second power switch Q2 constitutes the output terminal of the high-voltage drive module 320. The control terminals of the first power switch Q1 and the second power switch Q2 are connected to the high-voltage driver 323. The pulse generator 321 generates an excitation pulse of a set frequency, which is amplified by the buffer driver 322 and then sent to the high-voltage drive module 320. The high-voltage driver 323 uses the first power switch Q1 and the second power switch Q2 to generate a high-voltage excitation signal, and drives the acoustic transducer array 200 to emit ultrasonic waves through the transceiver switching network 310. After the emission is completed, the transceiver switching network 310 enters the receiving mode, and the acoustic transducer array 200 converts the received echo signal into a weak charge signal.

[0107] Meanwhile, the high-voltage driver 323 can be connected to the repair drive module 334 of the processing circuit 330 and receive drive control signals. The high-voltage driver 323 adjusts the frequency and amplitude of the amplified laser pulse according to the drive control signals and switches to output matching high-voltage excitation signals.

[0108] The signal processing module 332 includes a third capacitor C3, a charge amplifier 301, a low-noise amplifier 302 cascaded after the charge amplifier 301, and a bandpass filter 303 with an adjustable center frequency. All components work together to process weak charge signals.

[0109] The third capacitor C3 is used to receive weak charge signals and perform DC blocking. The charge amplifier 301 receives the weak charge signals from the acoustic transducer array 200 during the receiving period and converts them into voltage signals. Its gain is determined by the feedback capacitor. The amplitude of the weak charge signals output by the acoustic transducer array 200 is typically in the pC range and cannot be directly processed. The charge amplifier 301 converts the charge signals into voltage signals through the charging and discharging action of the feedback capacitor. The conversion gain can be adjusted by adjusting the capacitance of the feedback capacitor to ensure that the amplitude of the converted voltage signal meets the requirements of subsequent processing. Simultaneously, the charge amplifier 301 features high input impedance and low output impedance, effectively reducing signal loss.

[0110] The low-noise amplifier 302 is used to amplify the voltage signal output from the charge amplifier 301 with low noise, further increasing the signal amplitude while suppressing noise interference. The low-noise amplifier 302 is fabricated using a low-noise operational amplifier, which can flexibly adjust its gain according to the intensity of the echo signal, ensuring that the amplified signal amplitude remains stable within a suitable range and avoiding signal saturation or insufficient amplitude. The bandwidth of the low-noise amplifier 302 is adapted to the frequency of the ultrasonic detection signal, effectively preserving the characteristic information of the echo signal.

[0111] A bandpass filter 303 with an adjustable center frequency is used to filter the signal amplified by the low-noise amplifier 302 to remove noise signals outside the current operating center frequency of the acoustic transducer array 200, including environmental noise and broadband circuit noise. The center frequency of the bandpass filter 303 can be flexibly adjusted according to the frequency of the current ultrasonic detection signal or the frequency of the repair excitation signal, enabling precise filtering of noise signals in non-target frequency bands and improving the signal-to-noise ratio of the echo signal. The bandpass filter 303 adopts an active filter structure, featuring good filtering effect and strong out-of-band rejection capability.

[0112] The signal processing module 332, through the cascaded processing of charge amplifier 301, low-noise amplifier 302, and bandpass filter 303, solves the problem that the effective signal directly obtained from the piezoelectric transducer output is extremely weak and easily submerged in background noise, making it difficult to extract fine echo features such as time of flight and energy. The cascaded signal conditioning chain ensures that even under the harsh conditions of weak scattering from deep particles, the back-end signal processing module 332 can still obtain a clean signal source with a high signal-to-noise ratio, guaranteeing the accuracy of feature parameter extraction and afterimage recognition.

[0113] After the echo signal enters the signal processing module 332, the signal processing module 332 may further include a variable gain amplification module 304, an envelope detection module 305, and a signal processor 306. The echo signal undergoes time gain compensation through the variable gain amplification module 304 to compensate for attenuation differences during ultrasound propagation. Subsequently, the echo envelope information is extracted by the envelope detection module 305 and output to the signal processor 306. The signal processor 306 further performs peak detection, time-of-flight calculation, and energy statistical analysis to construct an echo feature vector. The echo feature vector can reflect the distribution, migration, and interface reflection states of electrophoretic particles inside the electronic paper from multiple dimensions, providing accurate data support for subsequent afterimage recognition.

[0114] Subsequently, the comparison and judgment module 333 of the processing circuit 330 compares the constructed echo feature vector with the reference feature vector corresponding to the image-free state, and determines whether there is an abnormal particle state in the currently detected area based on the comparison result. The reference feature vector is constructed by collecting echo signals from each area in the image-free state during the factory calibration stage of the electronic paper, extracting the corresponding feature parameters, and storing it in a non-volatile memory connected to the control processing unit 300.

[0115] When the comparison and judgment module 333 determines that there is an abnormal particle state in the current detection area, the processing circuit 330 immediately starts the repair mode. The repair drive module 334 of the processing circuit 330 generates and outputs a repair drive signal to the high voltage driver 323 according to the abnormality type, and outputs an ultrasonic excitation signal to the acoustic transducer array 200 through the high voltage driver 323 to apply ultrasonic repair excitation that matches the abnormality type to the abnormal area.

[0116] Furthermore, to avoid the problem that the control processing unit 300 initiates indiscriminate perturbation based solely on an anomaly flag, in an optional embodiment, the control processing unit 300 is configured to: The echo feature vector is compared with the reference feature vector, and a ghost image repair instruction is generated based on the deviation obtained from the comparison. The repair instruction includes the target repair type, target repair coordinates and repair excitation parameters determined according to the comparison deviation mode. According to the repair command, the repair mode is started, and the repair drive signal is synthesized and output.

[0117] In this embodiment, the control processing unit 300 is configured to compare the echo feature vector with the reference feature vector and generate a ghost image repair instruction based on the deviation obtained from the comparison. The repair instruction includes the target repair type, target repair coordinates and repair excitation parameters determined according to the comparison deviation mode. The control processing unit 300 starts the repair mode according to the repair instruction, synthesizes and outputs the repair drive signal.

[0118] The comparison and judgment module 333 of the control processing unit 300 compares the real-time echo feature vector with the reference feature vector, calculates the deviation of each feature parameter, and determines the target repair type based on the magnitude and pattern of the deviation. For example, if the peak amplitude feature deviation is -30% and the cumulative echo energy feature deviation is -25%, the target repair type is determined to be particle aggregation type; if the peak amplitude feature deviation is +20% and the time-of-flight feature deviation is -5ns, the target repair type is determined to be wall adsorption type. Simultaneously, the comparison and judgment module 333 determines the target repair coordinates based on the two-dimensional afterimage distribution matrix, clarifying the specific location of the abnormal area that needs repair.

[0119] The determination of the repair excitation parameters is based on the target repair type and the severity of the anomaly. The repair drive module 334 of the control processing unit 300 retrieves the corresponding basic repair parameters from a preset repair parameter library according to the target repair type, and then adjusts the basic repair parameters according to the severity of the anomaly to generate the final repair excitation parameters. The repair excitation parameters include ultrasonic frequency, pulse width, duty cycle, excitation amplitude, and excitation time. For example, for a high-severity particle aggregation anomaly, the basic repair parameters are a frequency of 1.8 MHz, a pulse width of 15 μs, and a duty cycle of 15%. The adjusted repair excitation parameters are a frequency of 1.9 MHz, a pulse width of 20 μs, a duty cycle of 20%, an increase in excitation amplitude of 20%, and an extension of excitation time of 30%.

[0120] The control processing unit 300 integrates the target repair type, target repair coordinates, and repair excitation parameters to generate a residual image repair command. The repair command uses a standardized data format to facilitate transmission and parsing between modules within the control processing unit 300. Subsequently, the control processing unit 300 initiates the repair mode according to the repair command. The repair drive module 334 synthesizes a repair drive signal based on the repair excitation parameters and drives the acoustic transducer array 200 to apply ultrasonic repair excitation to the abnormal area corresponding to the target repair coordinates through the array control logic 400 and the two-dimensional switch matrix 220.

[0121] By generating afterimage repair instructions containing multi-dimensional information, intelligent decision-making is achieved between anomaly detection and the execution of target physical actions. This solves the problem of indiscriminate perturbation being initiated based solely on an anomaly flag, creating a clear and programmable quantitative mapping relationship between repair actions and internal state deviation patterns. This provides an intermediate decision-making layer for achieving fine-grained control of automatically adjusting repair energy or strategies based on the severity of the anomaly. This fills the gap in intelligent decision-making between anomaly detection and the execution of target physical actions, enabling the system to make decisions on demand and further improving the accuracy and efficiency of repair.

[0122] In an optional embodiment, the electronic paper display device also has an electronic paper display lifespan prediction function. By long-term collection of echo characteristic data from various regions of the electronic paper, the state change trend of electrophoretic particles is analyzed to establish an electronic paper display lifespan prediction model. The control processing unit 300 periodically records the echo characteristic vectors of each detection region, calculates the rate of change of characteristic parameters, and, combined with parameters such as the usage time of the electronic paper, refresh count, and environmental conditions, predicts the display lifespan of each region of the electronic paper. If the particle state change rate of a certain region exceeds a preset threshold, the control processing unit 300 determines that the region has an aging risk, issues an aging warning signal, and reminds staff to handle it in time to avoid display failures caused by aging. The display lifespan prediction function can realize the health management of electronic paper, extend the overall service life of electronic paper, and reduce usage costs.

[0123] The electronic paper display device also features restoration effect statistics and optimization functions. The control processing unit 300 automatically records relevant data for each restoration, including the restoration area, afterimage type, restoration parameters, restoration time, and afterimage severity scores before and after restoration, constructing a restoration effect database. Through data analysis of the restoration effect database, the restoration effects of different afterimage types and restoration parameters are summarized, and the restoration parameter database and adaptive adjustment model are optimized to further improve restoration effect and efficiency. For example, analysis reveals that a 1.8MHz ultrasonic frequency is optimal for restoring particle agglomeration afterimages on a certain type of electronic paper. This parameter can be updated to the restoration parameter database, providing better parameter selection for subsequent restorations.

[0124] Furthermore, the electronic paper display device also features a self-diagnostic function, capable of real-time monitoring of the operating status of each module in the system, including the transmission and reception status of the acoustic transducer array 200, the output status of the high-voltage drive module 320, and the signal processing and computation status of the processing circuit 330. If a fault is detected in a module, such as no excitation signal output from the acoustic transducer array 200 or no signal input from the processing circuit 330, the control processing unit 300 will automatically issue a fault alarm signal and locate the faulty module and cause through a fault self-diagnosis program, while attempting fault self-recovery. For example, if a fault is detected in a piezoelectric transducer unit 210, the control processing unit 300 will automatically switch to the backup transducer unit to ensure the normal operation of detection and repair work; if the fault cannot be self-recovered, the control processing unit 300 will record the fault information and remind personnel to carry out maintenance. The fault self-diagnosis function can improve the reliability of the system and reduce interruptions in image retention detection and repair caused by system faults.

[0125] This invention has a wide range of applications, including various electronic paper display devices such as e-readers, smart office equipment, electronic shelf labels, automotive displays, industrial instruments, and smart home appliances. In the field of e-readers, it effectively solves the problem of image retention caused by prolonged reading, improving the reading experience. In the field of electronic shelf labels, it can adapt to the need for frequent price updates, preventing image retention from affecting the clarity of the price display. In the field of industrial instruments, it ensures the accuracy of displayed data, avoiding misreading caused by image retention. Furthermore, it can be extended to other electrophoretic display devices, demonstrating promising application prospects.

[0126] Example 2 A second aspect of this invention provides a method for image retention repair, applied to the electronic paper display device described above, such as... Figure 11 As shown, the methods for repairing image retention include: S10. In detection mode, control the acoustic transducer array 200 to transmit ultrasonic detection signals to the microcup electrophoretic layer 120 and receive echo signals returned from inside the microcup electrophoretic layer 120. S20. Extract feature parameters of multiple physical dimensions from the received echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer 120, so as to construct an echo feature vector. S30. Compare the constructed echo feature vector with the baseline feature vector corresponding to the no-afterimage state to determine whether there is an abnormal particle state in the currently detected area. S40. After determining that an abnormality exists, the repair mode is started, and a repair drive signal is generated and output to the acoustic transducer array 200 to apply ultrasonic repair excitation that matches the type of abnormality to the abnormal area.

[0127] In detection mode, the transceiver control module 331 drives the acoustic transducer array 200 to transmit ultrasonic detection signals and receive echo signals. Specifically, the control processing unit 300 controls the high-voltage drive module 320 to output a high-voltage pulse excitation signal to the acoustic transducer array 200, driving the piezoelectric transducer unit 210 in the acoustic transducer array 200 to generate ultrasonic mechanical vibration. The ultrasonic waves pass through the TFT driving layer 110 in the form of longitudinal waves and enter the microcup electrophoresis layer 120. Reflection and scattering occur at the microcup wall, the electrophoretic particle group, and the interfaces of each layer, forming echo signals. The acoustic transducer array 200 converts the received echo signals into weak charge signals.

[0128] The weak charge signal is processed to extract feature parameters of multiple physical dimensions characterizing the distribution state of electrophoretic particles inside the microcup electrophoretic layer 120, thereby constructing an echo feature vector. The echo feature vector reflects the distribution, migration, and interface reflection states of electrophoretic particles inside the electronic paper from multiple dimensions, providing accurate data support for subsequent image retention detection. Subsequently, the comparison and judgment module 333 compares the constructed echo feature vector with the baseline feature vector corresponding to the image-free state, and determines whether there is an abnormal particle state in the currently detected area based on the comparison result. The baseline feature vector is constructed by collecting echo signals from various areas in the image-free state during the electronic paper's factory calibration stage, extracting the corresponding feature parameters, and is stored in a non-volatile memory connected to the control processing unit 300.

[0129] When it is determined that there is an abnormal particle state in the current detection area, the repair mode is activated. The repair drive module 334 generates and outputs a repair drive signal to the acoustic transducer array 200 according to the abnormality type, so as to apply ultrasonic repair excitation that matches the abnormality type to the abnormal area.

[0130] Unlike the blind ultrasonic disturbances in existing technologies, the ultrasonic repair excitation in this embodiment is generated based on previously detected internal abnormal state information, which can accurately act on the abnormal area and avoid causing invalid disturbances to the normal display area.

[0131] Specifically, if the anomaly is determined to be particle aggregation type, a high-frequency short pulse group excitation signal is output; if the anomaly is determined to be wall adsorption type, a cavitation pulse group excitation signal at the target frequency is output; if the anomaly is determined to be migration hysteresis type, a broadband sweep frequency excitation signal is output.

[0132] After the repair stimulus is applied, switch back to the detection mode, re-acquire the echo signal of the repair area, construct a new echo feature vector and compare it with the benchmark feature vector to verify the repair effect and form a closed-loop self-healing control.

[0133] By reconstructing the acoustic transducer array 200 into an integrated dual-function module that combines active acoustic detection and repair excitation, a fundamental shift has been achieved from indirect inference based on visual differences or empirical thresholds to direct quantitative measurement based on internal physical state signals. This enables the detection of particle state anomalies before the afterimage appears at the visual level, significantly improving the timeliness and energy efficiency of afterimage elimination, while reducing power consumption waste caused by ineffective driving and the risk of aging of the internal structure of electronic paper.

[0134] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. An electronic paper display device, characterized in that, include: The display panel includes a microcup electrophoresis layer and a driving layer for driving the microcup electrophoresis layer; An acoustic transducer array is integrated on the back panel side of the display panel. The acoustic transducer array is used to emit ultrasonic detection signals to the microcup electrophoretic layer and receive echo signals returned from inside the microcup electrophoretic layer. Control processing unit, used for: In detection mode, the acoustic transducer array is driven to perform signal transmission and reception, and multiple physical dimension feature parameters are extracted from the echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer, so as to construct an echo feature vector. The echo feature vector is compared with the reference feature vector corresponding to the no-afterimage state to determine whether there is an abnormal particle state in the currently detected area. After determining that there is an abnormal particle state, the repair mode is activated, and a repair driving signal is generated and output to the acoustic transducer array to apply ultrasonic repair excitation that matches the abnormality type to the abnormal area. The acoustic transducer array includes multiple piezoelectric transducer units; The control processing unit is further configured to: Addressing scans are performed on multiple piezoelectric transducer units to sequentially obtain independent echo feature vectors for each sub-region of the display panel corresponding to each piezoelectric transducer unit; Based on the deviation between the independent echo feature vector of each sub-region and the corresponding reference feature vector, a two-dimensional afterimage distribution matrix is ​​constructed to mark the spatial location of the sub-regions of the display panel where particle state anomalies exist. The control processing unit is used for: In the repair mode, the piezoelectric transducer unit corresponding to the abnormal region and multiple piezoelectric transducers adjacent to the abnormal region work together. The electronic paper display device further includes a phase controller connected to the control processing unit. The phase controller is used to introduce a delay amount into each drive signal selected and output by the control processing unit so that the ultrasonic waves emitted by the multiple piezoelectric transducers are superimposed in phase at the spatial position of the abnormal area to form acoustic energy focusing.

2. The electronic paper display device as described in claim 1, characterized in that, The feature parameters of the multiple physical dimensions include at least: Peak amplitude characteristics are used to characterize the reflection intensity of the echo signal; The time-of-flight characteristic is used to characterize the time difference between the arrival time of the main reflected echo in the echo signal and the emission time of the ultrasonic detection signal, so as to reflect the position of the reflection interface inside the microcup electrophoretic layer. The cumulative echo energy characteristic is used to characterize the energy integral of the echo signal within a preset time window, so as to reflect the degree of aggregation of the electrophoretic particles; Echo attenuation characteristics are used to characterize the amplitude attenuation relationship between echoes generated by different reflecting interfaces in the echo signal, so as to reflect the propagation loss of ultrasound in the electrophoretic particle region.

3. The electronic paper display device as described in claim 2, characterized in that, The control processing unit is further configured to: Multiple ultrasonic detection excitation signals of different frequencies are output to the acoustic transducer array in a time-division manner; Echo signals at various frequencies are acquired and processed to construct a multi-frequency acoustic fingerprint containing multi-frequency response features; The multi-frequency acoustic fingerprint is matched with a pre-established acoustic fingerprint database to identify the type of afterimage in the abnormal region. The acoustic fingerprint database stores the mapping relationship between various particle anomaly causes and corresponding standard multi-frequency response modes.

4. The electronic paper display device as described in claim 3, characterized in that, In the repair mode, the control processing unit selects a corresponding target repair strategy from a set of preset differentiated repair strategies based on the identified specific type of afterimage, in order to generate the repair driving signal. The multiple sets of differentiated repair strategies include at least one of the following: The first repair strategy is to generate a high-frequency short pulse group excitation signal to break up the particle aggregation structure. The second repair strategy is to generate a cavitation pulse group excitation signal at a target frequency to strip off the particle layer adsorbed on the wall surface. The third repair strategy is to generate a broadband sweep frequency excitation signal to enhance the mobility of the hysteresis particles. The fourth repair strategy is to generate a low-frequency modulated excitation signal to restore the uniformity of the electric field.

5. The electronic paper display device as described in claim 4, characterized in that, After completing one ultrasonic repair excitation, the control processing unit re-executes the state detection and echo feature vector construction operations under the detection mode on the abnormal area. The newly obtained echo feature vector after repair is compared with the reference feature vector to verify the repair effect. If the deviation still exceeds the preset threshold, the parameters of the repair driving signal are adjusted and the repair excitation is applied again to form a closed-loop self-healing control.

6. The electronic paper display device according to any one of claims 1 to 5, characterized in that, The control processing unit includes: High-voltage drive module, used for controlled output of high-voltage pulse excitation signal; A transceiver switching network is connected to the high-voltage drive module and the acoustic transducer array. The transceiver switching network is used to controllably connect the output terminals of the acoustic transducer array and the high-voltage drive module, or to controllably transmit the echo signal of the acoustic transducer array to the back end. The processing circuit, connected to the transceiver switching network and the high-voltage drive module, is used for: In detection mode, a high-voltage control signal is output to the high-voltage drive module, and a transmit / receive switching signal is output to the transmit / receive switching network to control the acoustic transducer array to perform signal transmission and reception. Multiple physical dimension feature parameters are extracted from the echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer, so as to construct an echo feature vector. The echo feature vector is compared with the reference feature vector corresponding to the no-afterimage state to determine whether there is an abnormal particle state in the currently detected area. After determining that there is an abnormal particle state, the repair mode is activated, and a repair drive signal is generated and output to the high-voltage drive module to apply ultrasonic repair excitation matching the abnormality type to the abnormal area through the high-voltage drive module and the acoustic transducer array.

7. The electronic paper display device as claimed in claim 6, characterized in that, The control processing unit is used for: The echo feature vector is compared with the reference feature vector, and a ghost image repair instruction is generated based on the deviation obtained from the comparison. The repair instruction includes the target repair type, target repair coordinates and repair excitation parameters determined according to the comparison deviation mode. According to the repair instruction, the repair mode is activated, and the repair drive signal is synthesized and output.

8. A method for repairing image retention, applied to an electronic paper display device as described in any one of claims 1 to 7, characterized in that, The image restoration method includes: In detection mode, the acoustic transducer array is controlled to emit ultrasonic detection signals toward the microcup electrophoretic layer and receive echo signals returned from inside the microcup electrophoretic layer. Multiple physical dimension feature parameters are extracted from the received echo signal to characterize the distribution state of electrophoretic particles inside the microcup electrophoretic layer, so as to construct an echo feature vector. The constructed echo feature vector is compared with the reference feature vector corresponding to the no-afterimage state to determine whether there is an abnormal particle state in the currently detected area. After determining that an anomaly exists, the repair mode is activated, and a repair drive signal is generated and output to the acoustic transducer array to apply ultrasonic repair excitation that matches the type of anomaly to the abnormal area.

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