Signal feedback method, readable storage medium and scanning display device

Abstract

The application discloses a signal feedback method, a readable storage medium and a scanning display device. A driving circuit of a scanning display device comprises a piezoelectric actuator, an inductor and a voltage source. The method comprises the following steps: acquiring a driving frequency and a frequency characteristic curve of the piezoelectric actuator; the frequency characteristic curve comprises at least one resonance peak; detecting a voltage amplitude-frequency curve of the inductor and a voltage amplitude-frequency curve of the piezoelectric actuator in a frequency interval near the resonance peak; and selecting a voltage signal between the inductor and the piezoelectric actuator as a feedback signal based on the driving frequency of the piezoelectric actuator, the voltage amplitude-frequency curve of the inductor and the voltage amplitude-frequency curve of the piezoelectric actuator. By selecting the voltage signal between the piezoelectric actuator and the inductor as the feedback signal, the technical problem of increasing the volume, power consumption, cost and production and assembly complexity of the scanner module caused by the additional sensor is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of scanning display, in particular to a signal feedback method, a readable storage medium and a scanning display device. BACKGROUND

[0002] The imaging principle of fiber scanning display (FSD) is that a fiber scanner drives a fiber to move along a predetermined two-dimensional scanning trajectory, and modulates the light output by a light source corresponding to each pixel point of an image to be displayed, and then the light corresponding to each pixel point of the image to be displayed is projected one by one onto a projection surface by the fiber to form a projection picture.

[0003] In the projection display process, it is necessary to accurately control the scanning trajectory of the scanner. In the prior art, the scanner feedback control is generally realized by adding an external sensor to measure the vibration of the scanner or the fiber. For example, the scanner deformation is measured, the scanner vibration information is measured through a magnetic field, an electric field, or the image content projected by the scanner is detected through an optical device. These schemes all need to add additional sensors, which will inevitably increase the volume, power consumption, cost of the scanner module, and the production and assembly complexity. SUMMARY

[0004] The purpose of the present application is to provide a signal feedback method, a readable storage medium and a scanning display device, which can solve the technical problems that the feedback control schemes in the prior art all need to add additional sensors, which will increase the volume, power consumption, cost of the scanner module, and the production and assembly complexity.

[0005] In order to achieve the above-mentioned application purpose, the first aspect of the embodiment of the present application provides a signal feedback method applied to a scanning display device, wherein the driving circuit of the scanning display device includes a piezoelectric actuator, an inductor connected in series with the piezoelectric actuator, and a voltage source; and the method comprises the following steps:

[0006] obtaining the driving frequency and the frequency characteristic curve of the piezoelectric actuator; the frequency characteristic curve includes at least one resonance peak;

[0007] detecting the voltage amplitude-frequency curve of the inductor and the voltage amplitude-frequency curve of the piezoelectric actuator in the frequency range near the resonance peak;

[0008] selecting the voltage signal across the inductor or the piezoelectric actuator as the feedback signal based on the driving frequency of the piezoelectric actuator, the voltage amplitude-frequency curve of the inductor, and the voltage amplitude-frequency curve of the piezoelectric actuator.

[0009] Optionally, based on the driving frequency of the piezoelectric actuator, the voltage amplitude-frequency curve of the inductor and the voltage amplitude-frequency curve of the piezoelectric actuator, the voltage signal across the inductor or the piezoelectric actuator is selected as the feedback signal, comprising:

[0010] calculating the slope of the voltage amplitude-frequency curve of the inductor at the driving frequency of the piezoelectric actuator, and the slope of the voltage amplitude-frequency curve of the piezoelectric actuator at the driving frequency of the piezoelectric actuator;

[0011] if the corresponding slope of the voltage amplitude-frequency curve of the inductor is greater than the corresponding slope of the voltage amplitude-frequency curve of the piezoelectric actuator, the voltage signal across the inductor is selected as the feedback signal;

[0012] if the corresponding slope of the voltage amplitude-frequency curve of the inductor is less than the corresponding slope of the voltage amplitude-frequency curve of the piezoelectric actuator, the voltage signal across the piezoelectric actuator is selected as the feedback signal.

[0013] Optionally, the frequency characteristic curve comprises an impedance curve or a frequency response curve.

[0014] Optionally, when the scanning display device is in a working state, the piezoelectric actuator forms an LC resonance circuit with the inductor as a capacitor; the resonance frequency of the LC resonance circuit is greater than the resonance frequency of the piezoelectric actuator, the resonance frequency of the optical fiber and the driving frequency of the driving signal output by the voltage source.

[0015] The second aspect of the embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize the steps of the method of the first aspect.

[0016] The third aspect of the embodiment of the present application provides a scanning display device, comprising a scanning display device, a processor and a computer readable storage medium.

[0017] The driving circuit of the scanning display device comprises a piezoelectric actuator, an inductor connected in series with the piezoelectric actuator and a voltage source.

[0018] The computer readable storage medium stores a computer program, and the program is executed by a processor to realize the steps of the method of the first aspect.

[0019] The one or more technical solutions in the embodiment of the present application have at least the following technical effects or advantages:

[0020] In the scheme of the embodiment of the present application, the scanning display device is driven by LC resonance, and when the scanning display device is in the working state, the voltage signal across the piezoelectric actuator or the inductor is selected as the feedback signal, thereby avoiding the additional sensor, and relieving the technical problems of increasing the volume, power consumption, cost, and production and assembly complexity of the scanner module caused by the additional sensor. The scheme can realize the feedback control of the scanner without additional sensors, ensure that the display image of the scanner does not change when the external working conditions change, and reduce the volume and weight of the feedback part of the scanner display module, and reduce the power consumption and cost of the scanner display module. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 A possible LC resonance driving circuit provided by the embodiment of the present application is shown in the schematic diagram;

[0023] Figure 2 A possible LC resonance driving circuit provided by the embodiment of the present application is shown in the schematic diagram;

[0024] Figure 3 A possible LC resonance driving circuit provided by the embodiment of the present application is shown in the schematic diagram;

[0025] Figure 4 A possible LC resonance driving circuit provided by the embodiment of the present application is shown in the schematic diagram;

[0026] Figure 5 A possible LC resonance driving circuit provided by the embodiment of the present application is shown in the schematic diagram;

[0027] Figure 6 A possible LC resonance driving circuit provided by the embodiment of the present application is shown in the schematic diagram. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0029] Please refer to Figure 1 ,Figure 1 The schematic diagram of the piezoelectric driving circuit structure provided by the embodiment of the present application. In the embodiment of the present application, the scanning display device adopts LC resonance driving, and the voltage signal between the piezoelectric actuator or the inductor is taken as the feedback signal.

[0030] The piezoelectric driving circuit structure comprises two parts, namely a driving circuit and a detection circuit. The driving circuit comprises a piezoelectric actuator C1, an inductor L1 connected in series with the piezoelectric actuator C1, and a voltage source V1. When the scanning display device is in the working state, the piezoelectric actuator C1 forms an LC resonance loop as a capacitor with the inductor L1; the detection circuit is used for collecting the voltage signal between the piezoelectric actuator or the inductor as the feedback signal, and the signal led out from the FB end is the voltage signal between the piezoelectric ceramics.

[0031] In the embodiment of the present application, the piezoelectric actuator C1 is mainly composed of piezoelectric ceramics, and the inverse piezoelectric effect of the piezoelectric ceramics is used to convert the electrical signal into mechanical vibration. Taking the optical fiber scanning display device as an example, the optical fiber is fixed on the piezoelectric actuator, the optical fiber fixed on the piezoelectric actuator is driven to vibrate through the vibration of the piezoelectric actuator, and the image scanning is realized through the light emission of the optical fiber.

[0032] For the scanning display device of the grid format scanning mode, the piezoelectric actuator comprises two actuating parts, which respectively provide X-axis direction driving and Y-axis direction driving. Generally, the Y-axis direction driving frequency is less than the X-axis direction driving frequency, therefore, the two actuating parts can also be respectively called slow axis (Y-axis) actuating part and fast axis (X-axis) actuating part, and the optical fiber scans according to the grid format track under the synergistic action of the vibrations generated by the two actuating parts. Therefore, for the grid format scanning mode, the two actuating parts can be respectively regarded as two driving axes of the optical fiber scanning display device. Since the fast axis track is amplified by the resonance of the optical fiber, it is more susceptible to external influences, and responds to the track change, which leads to the change of the display image and the display abnormality, such as the change of the fast axis swing, the picture ellipse, the picture squareness, the odd-even line coincidence degree and the like, which will cause the image display abnormality. Therefore, for the grid format scanning mode, the feedback control of the fast axis direction vibration is generally required.

[0033] For the scanning display device of the Lissajous scanning mode or the spiral scanning mode, the X-axis and Y-axis scanning tracks are both amplified by the resonance of the optical fiber, therefore, the feedback control of the vibrations of the optical fiber in two directions is required.

[0034] In the embodiment of the present application, the piezoelectric actuator can be the X-axis actuating part or the Y-axis actuating part, the feedback signal is directly sampled from the driving circuit, and there is no need to lead out the feedback signal lead from the piezoelectric actuator, the signals of the X-axis and Y-axis will not be coupled, and the X-axis and Y-axis can be independently controlled, so that the signal decoupling processing is not required.

[0035] In the embodiment of the present application, within the working temperature range of the scanner, the LC resonant circuit resonant frequency f lc is required to be greater than the actuator resonant frequency f p , the optical fiber resonant frequency f f and the driving frequency f d .

[0036] Due to the change of temperature, the piezoelectric ceramic response characteristics will change, the impedance curve and the frequency response curve of the piezoelectric ceramic will be shifted. The LC resonant circuit resonant frequency f lc , the actuator resonant frequency f p , and the optical fiber resonant frequency f f will also change. For the scanning display device, the driving frequency of the piezoelectric actuator is determined by the display requirements of the scanning display device, therefore, the position relationship between the driving frequency f d and the resonance peak of the impedance curve / frequency response curve will change, and it is required to ensure that f d always remains on one side of the resonance peak of the impedance curve / frequency response curve.

[0037] The impedance curve is obtained by sweeping the frequency of the alternating voltage signal applied to the piezoelectric ceramic, measuring the amplitude and phase of the current waveform, and then calculating the impedance curve and the frequency response curve. The piezoelectric ceramic is driven by an alternating voltage signal to produce deformation and drive the overall vibration. The vibration mode of the piezoelectric ceramic changes with the frequency, and the stress distribution inside the ceramic also changes, resulting in changes in the internal charge distribution under the action of the piezoelectric effect, and ultimately resulting in changes in the driving current. Therefore, the impedance curve and the frequency response curve measured by the impedance analyzer can reflect the mechanical vibration frequency response characteristics.

[0038] As shown in Figure 2 and Figure 3 , in the LC series resonant circuit, near the resonance peak of the impedance curve, the inductance and capacitance voltage frequency curve is shown. Figure 2 The inductance voltage amplitude-frequency curve a and the loop total current amplitude-frequency curve b, Figure 3 The capacitance voltage frequency curve c and the loop total current amplitude-frequency curve d.

[0039] As shown in Figure 2 and Figure 3 , the inductance voltage amplitude-frequency curve a has a high slope on the left side of the resonance peak, and the capacitance voltage amplitude-frequency curve c has a high slope on the right side. When used as a feedback signal, high signal sensitivity is required, therefore, the curve slope should be as high as possible. Therefore, the voltage signal across the piezoelectric actuator or the inductance can be selected as the feedback signal according to the driving frequency of the piezoelectric actuator. As shown in Figure 4 , the flowchart of the signal feedback method provided in the embodiment of the present application includes the following steps.

[0040] In step 401, the driving frequency of the piezoelectric actuator and the frequency characteristic curve are obtained; the frequency characteristic curve includes at least one resonance peak; wherein the driving frequency of the piezoelectric actuator is determined by the display requirement of the scanning display device, and the frequency characteristic curve includes an impedance curve or a frequency response curve.

[0041] In step 402, the voltage amplitude-frequency curve of the inductor and the voltage amplitude-frequency curve of the piezoelectric actuator are detected in the frequency interval near the resonance peak.

[0042] In step 403, based on the driving frequency of the piezoelectric actuator, the voltage amplitude-frequency curve of the inductor and the voltage amplitude-frequency curve of the piezoelectric actuator, the voltage signal across the inductor or the piezoelectric actuator is selected as the feedback signal.

[0043] As shown in Figure 2 and Figure 3 , at the driving frequency of the piezoelectric actuator, the slope of the inductor voltage amplitude-frequency curve and the slope of the capacitor voltage amplitude-frequency curve are calculated, and then the voltage signal across the element with higher curve slope is selected as the feedback signal, so as to improve the signal sensitivity. For example, if the voltage amplitude-frequency curve of the inductor corresponds to a higher slope at the driving frequency of the piezoelectric actuator, the voltage signal across the inductor is selected as the feedback signal. If the voltage amplitude-frequency curve of the capacitor corresponds to a higher slope at the driving frequency of the piezoelectric actuator, the voltage signal across the piezoelectric actuator is selected as the feedback signal.

[0044] In a possible implementation, when the scanning display device is driven, the capacitor C is replaced by the piezoelectric ceramic of the driving shaft of the scanning display device. When the temperature changes, the equivalent capacitance of the driving electrode of the scanning display device changes with the temperature, and the voltage signal across the capacitor C can be selected as the feedback signal. Correspondingly, the driving frequency needs to be selected on the right side of the LC resonance peak.

[0045] When the voltage signal across the capacitor C is selected as the feedback signal, the connection mode of the LC circuit is as shown in Figure 1 The inductor L1 is on the upper end of the capacitor C1, and the signal led out from the FB end is the voltage across the piezoelectric ceramic. After being divided, the signal is directly sent to the detection circuit. Since the signal amplitude is large, an amplification circuit is not needed in the embodiment of the present application.

[0046] If C is on the upper end of L, the signal needs to be led out in the mode as shown in Figure 5 Since the driving voltage of the piezoelectric ceramic is high, a sampling circuit with high-voltage differential input is needed.

[0047] When the voltage signal across the inductor L is selected as the feedback signal, the connection mode of the LC circuit is as shown in Figure 6As shown, the inductor L2 is at the lower end of the capacitor C2, and the signal from the FB terminal is the voltage across the inductor, which is directly sent to the detection circuit after being divided.

[0048] Next, the feedback control process in the embodiment of the application is described.

[0049] The first possible implementation

[0050] In a small temperature range, the impedance curve and the frequency response curve of the scanning display device are scanned, and the change of the frequency response curve is mainly a whole translation, so that the feedback control can be realized in the following manner. First, the scanner is initialized, and the initial value of the feedback signal is recorded, then, during the operation of the scanning display device, the amplitude and phase of the feedback signal are sampled in real time, the error between the amplitude and phase of the real-time sampled feedback signal and the initial value of the feedback signal is calculated, and the error is sent to the PID controller to adjust the amplitude and phase of the driving signal respectively.

[0051] The second possible implementation

[0052] The feedback control is realized through temperature calibration, and when the control accuracy of the scanning display device is high, the non-linear change of the impedance curve and the frequency response curve of the scanner needs to be considered.

[0053] When the temperature range is too large, the impedance curve of the piezoelectric actuator may change slightly, which is reflected in the change of the slope of the resonance peak. When the range of the driving voltage applied to the piezoelectric actuator is too large, the frequency response curve of the piezoelectric ceramic of the scanning display device will also have a non-linear change. Therefore, the scanning display device can be controlled in feedback in the following manner.

[0054] First, the scanner is initialized at different temperatures, and the amplitude and phase of the driving voltage and the amplitude and phase of the feedback signal are recorded.

[0055] Taking the amplitude of the feedback signal as the independent variable and the driving voltage as the dependent variable, the fitting function F vd (v fb ) is obtained.

[0056] Taking the amplitude of the driving voltage as the independent variable and the phase of the feedback signal as the dependent variable, the fitting function F θ (v d ) is obtained.

[0057] When the amplitude feedback control is performed, the amplitude of the feedback signal is collected, and the error e=F vd (v fb ) is calculated, where e is the error value, V vd is the current driving voltage, and V fb is the initial value of the driving voltage. d , V d is the current driving voltage, and V fbFor the feedback signal amplitude, then, the error e is sent into the PID controller to realize the amplitude feedback control.

[0058] When the phase feedback control is performed, the feedback signal phase is collected and brought into the function F θ (v d ), to calculate the error e θ = θ - F θ (v d ), where e θ is the error value, V d is the current driving voltage, and θ is the feedback signal phase. Then, e θ is sent into the PID controller to realize the amplitude feedback control.

[0059] Based on the same inventive concept, the embodiments of the present application also provide a scanning display device, which comprises the circuit structure and the processor as described in the above embodiments, and the processor is used to receive the feedback signal collected by the detection circuit and correct the driving signal output by the voltage source according to the feedback signal. The specific correction process has been described in the feedback control flow in the above embodiments, and thus will not be described in detail herein.

[0060] All features disclosed in this specification, and / or all steps of any methods or processes disclosed, can be combined in any combination, except combinations where at least some of the features and / or steps are mutually exclusive.

[0061] Any feature disclosed in this specification, unless stated otherwise, can be replaced by any equivalent or other technically feasible feature, or any technically feasible combination of features. That is, unless stated otherwise, each feature is merely one example of a range of equivalent or similar features.

[0062] The present application is not limited to the specific embodiments described above. The present application extends to any novel one, or any novel combination, of the features disclosed in this specification, and to any novel method or process disclosed, or any novel step of any novel method or process disclosed, or any novel combination of steps.

Claims

1. A signal feedback method applied in a scanning display device, characterized in that, The driving circuit of the scanning display device comprises a piezoelectric actuator, an inductor connected in series with the piezoelectric actuator, and a voltage source; the method comprises: acquiring a driving frequency of the piezoelectric actuator and a frequency characteristic curve of the piezoelectric actuator; the frequency characteristic curve comprises at least one resonance peak; detecting a voltage amplitude-frequency curve of the inductor and a voltage amplitude-frequency curve of the piezoelectric actuator in a frequency range near the resonance peak; selecting a voltage signal across the inductor or the piezoelectric actuator as a feedback signal based on the driving frequency of the piezoelectric actuator, the voltage amplitude-frequency curve of the inductor, and the voltage amplitude-frequency curve of the piezoelectric actuator.

2. The method of claim 1, wherein, The selecting of the voltage signal across the inductor or the piezoelectric actuator as the feedback signal based on the driving frequency of the piezoelectric actuator, the voltage amplitude-frequency curve of the inductor, and the voltage amplitude-frequency curve of the piezoelectric actuator comprises: calculating a slope of the voltage amplitude-frequency curve of the inductor at the driving frequency of the piezoelectric actuator, and a slope of the voltage amplitude-frequency curve of the piezoelectric actuator at the driving frequency of the piezoelectric actuator; if the corresponding slope of the voltage amplitude-frequency curve of the inductor is greater than the corresponding slope of the voltage amplitude-frequency curve of the piezoelectric actuator, selecting the voltage signal across the inductor as the feedback signal; if the corresponding slope of the voltage amplitude-frequency curve of the inductor is less than the corresponding slope of the voltage amplitude-frequency curve of the piezoelectric actuator, selecting the voltage signal across the piezoelectric actuator as the feedback signal.

3. The method of claim 2, wherein, The frequency characteristic curve comprises an impedance curve or a frequency response curve.

4. The method of claim 1, wherein, When the scanning display device is in a working state, the piezoelectric actuator forms an LC resonance circuit with the inductor as a capacitor; the resonance frequency of the LC resonance circuit is greater than the resonance frequency of the piezoelectric actuator, the resonance frequency of the optical fiber, and the driving frequency of the driving signal output by the voltage source.

5. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the steps of the method of any one of claims 1-4.

6. A scanning display device, characterized by The scanning display device, the processor, and the computer readable storage medium are included; The driving circuit of the scanning display device comprises a piezoelectric actuator, an inductor connected in series with the piezoelectric actuator, and a voltage source; The computer readable storage medium stores a computer program, which is executed by the processor to implement the steps of the method of any one of claims 1-4.

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