Piezoelectric scanning device and scanning display module

Abstract

The utility model discloses a piezoelectric scanning device and a scanning display module. The piezoelectric scanning device comprises a piezoelectric actuator; the constant temperature element is arranged on the surface of the piezoelectric actuator, and the constant temperature element is used for conducting temperature compensation on the piezoelectric actuator in the scanning process of the piezoelectric actuator. According to the scheme, temperature compensation is carried out on the piezoelectric actuator in the scanning process of the piezoelectric actuator through the constant-temperature element arranged on the surface of the piezoelectric actuator, so that the influence of environment temperature change on the characteristics of the piezoelectric actuator is eliminated, and the performance stability of the piezoelectric actuator is ensured.

Description

Technical Field

[0001] The utility model relates to the field of projection display, in particular to a piezoelectric scanning device and a scanning display module. Background Art

[0002] The imaging principle of fiber scanning display (FSD) technology is to use an actuator to drive the optical fiber to move along a predetermined two-dimensional scanning trajectory, and modulate the light source to output the light corresponding to each pixel of the image to be displayed. Then, the light corresponding to each pixel of the image to be displayed is projected one by one onto the projection surface through the optical fiber to form a projection picture.

[0003] In FSD applications, the actuator is usually composed of multiple piezoelectric devices, and the structure is generally complex, resulting in complex frequency characteristics. When the temperature changes, the characteristics of the piezoelectric actuator change nonlinearly, which will cause changes in the projected image and affect the imaging quality. Utility Model Content

[0004] The purpose of the utility model is to provide a piezoelectric scanning device and a scanning display module, which are used to alleviate the technical problem existing in the prior art that when the temperature changes, the characteristic change of the piezoelectric actuator is nonlinear, which will cause the projection picture to change and affect the imaging quality.

[0005] In order to achieve the above-mentioned utility model object, the first aspect of the utility model embodiment provides a piezoelectric scanning device, including:

[0006] Piezoelectric actuators;

[0007] A constant temperature element is arranged on the surface of the piezoelectric actuator, and the constant temperature element is used to perform temperature compensation on the piezoelectric actuator during the scanning process of the piezoelectric actuator.

[0008] Optionally, the piezoelectric actuator is a sheet-like structure, and the constant temperature element is arranged on the upper surface and / or the lower surface of the piezoelectric actuator.

[0009] Optionally, the constant temperature element is a TEC semiconductor device.

[0010] Optionally, the thermostatic element is a heating element.

[0011] Optionally, the heating element is made of a positive temperature coefficient PTC material.

[0012] Optionally, the PTC material is disposed on the surface of the piezoelectric actuator by coating.

[0013] A second aspect of the present invention provides a scanning display module, including:

[0014] A shell and the piezoelectric scanning device as described in the first aspect; the piezoelectric actuator is fixed inside the shell through a supporting structure.

[0015] Optionally, the shell is a vacuum sealing structure.

[0016] Optionally, a heat insulation layer is provided on the outer surface of the shell.

[0017] Optionally, the inner surface of the shell is a mirror surface.

[0018] One or more technical solutions in the embodiments of the present utility model have at least the following technical effects or advantages:

[0019] In the scheme of the embodiment of the utility model, by setting a constant temperature element on the surface of the piezoelectric actuator, the piezoelectric actuator is temperature compensated during the scanning process of the piezoelectric actuator, thereby eliminating the influence of ambient temperature changes on the characteristics of the piezoelectric actuator and ensuring the performance stability of the piezoelectric actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor:

[0021] Figure 1 A schematic diagram of the structure of a piezoelectric scanning device provided in an embodiment of the utility model;

[0022] Figure 2 A system block diagram of a scanning display module provided by an embodiment of the utility model;

[0023] Figure 3 A schematic diagram of a driving circuit of a piezoelectric actuator provided in an embodiment of the utility model;

[0024] Figure 4 A schematic structural diagram of a scanning display module provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] In the embodiment of the utility model, since the actuator part is mainly composed of piezoelectric ceramic PZT, the response characteristics of the scanner will change with changes in environmental conditions such as temperature. The purpose of the utility model is to compensate for the change in the actuator response characteristics caused by changes in external conditions such as temperature. In practical applications, the piezoelectric actuator can also use other piezoelectric materials, and the utility model does not limit this.

[0027] For the scheme using drive signal compensation, complex calibration and other measures are required to obtain the characteristics of the actuator changing with temperature, and then compensate through the drive signal. For the scheme using vibration trajectory detection for compensation, such systems are generally more complex and not friendly to mass production, resulting in high system production costs.

[0028] For the solution in the embodiment of the utility model, Figure 1 As shown, it is a structural schematic diagram of a piezoelectric scanning device, which includes a piezoelectric actuator 11 and a constant temperature element 12; the constant temperature element 12 is arranged on the surface of the piezoelectric actuator 11, and the constant temperature element 12 is used to perform temperature compensation on the piezoelectric actuator 11 during the scanning process of the piezoelectric actuator 11.

[0029] In the above solution, the operating temperature of the piezoelectric actuator 11 is maintained stable by the thermostatic element 12 , thereby eliminating the influence of the ambient temperature change on the characteristics of the piezoelectric actuator 11 and ensuring the performance stability of the piezoelectric actuator 11 .

[0030] In the embodiment of the utility model, the thermostatic element 12 can use TEC semiconductor devices to achieve cooling and heating at the same time. In order to simplify the structure and reduce the volume, materials such as PTC (Positive Temperature Coefficient) can also be used to achieve the heating function to maintain the FSD operating temperature higher than the product's maximum rated operating environment temperature, that is, T fsd =T max +dT, where T fsd is the internal temperature of the device, T max is the maximum rated operating temperature of the device. The value of dT can be selected according to actual needs to maintain T fsd When the temperature is higher than the working environment temperature, the influence of the ambient temperature change on the characteristics of the piezoelectric actuator 11 can be eliminated, thereby ensuring the performance stability of the piezoelectric actuator 11.

[0031] In the embodiment of the utility model, the setting mode of the thermostatic element 12 can be selected according to the different structures of the piezoelectric scanning device. For example, assuming that the piezoelectric actuator 11 is a sheet structure, the thermostatic element 12 can be set on the upper surface or the lower surface of the piezoelectric actuator 11, or on both the upper surface and the lower surface; and when the piezoelectric actuator 11 is a tubular structure, the thermostatic element 12 can be set on the outer surface of the tubular structure or the inner surface of the tubular structure, or on both the inner surface and the outer surface of the tubular structure, and the utility model does not limit this.

[0032] In the embodiment of the present invention, the following control method can be used to perform temperature compensation on the piezoelectric actuator 11 .

[0033] By utilizing the temperature characteristics of the piezoelectric actuator 11 itself, the electrical signals (voltage signal / current signal) at both ends of the piezoelectric actuator 11 after temperature drift are extracted as feedback signals, and the constant temperature element 12 is adjusted based on the feedback signals, thereby performing temperature compensation on the piezoelectric actuator 11.

[0034] When extracting the electrical signal in the driving circuit 13 of the piezoelectric actuator 11 , the voltage signal or the current signal of the piezoelectric ceramic may be extracted as the feedback signal according to different driving modes of the piezoelectric ceramic.

[0035] For example, Figure 2 As shown, the scanning display module includes a driving circuit 13 and a temperature compensation controller 14. Figure 3 As shown, when the LC driving method is adopted, the free end voltage waveform of the piezoelectric actuator 11 can be used as the feedback signal. The FB end voltage signal can be used as the feedback signal. Since the amplitude and phase of the voltage signal at FB will change after the piezoelectric ceramic produces temperature drift, the amplitude and phase of the voltage signal can be used as feedback signals. Furthermore, since the amplitude detection circuit has a simpler structure than the phase detection circuit, the amplitude signal can be selected as the feedback error signal.

[0036] Of course, the current of the piezoelectric ceramic can also be used as the feedback signal. Similarly, the amplitude of the current signal can be selected as the feedback error signal. In the specific implementation process, the current signal can be collected by connecting a sampling resistor in series with the ground terminal of the piezoelectric ceramic.

[0037] In the embodiment of the utility model, when performing temperature compensation, a PID controller can be used as a temperature compensation controller. After the FSD actuator image is initialized correctly, the feedback signal value is extracted and recorded as the signal initial value S0 as the preset value of the PID controller. During the operation of the FSD actuator, the feedback signal St is collected in real time. The PID controller error input value is set to Error = St-S0. In the specific implementation process, a better control effect can be obtained by adjusting the PID parameters, and the preset condition corresponding to the difference Error can be set near 0, thereby achieving real-time and precise temperature compensation.

[0038] In the above scheme, through the built-in temperature adjustment mechanism, the piezoelectric ceramic's own electrical signal is used as the controller error input, which can achieve accurate control of the PZT actuator temperature without adding external sensors and complex circuits, ensuring the performance stability of the piezoelectric actuator 11 in a wide temperature range, and significantly improving the reliability and real-time performance of the piezoelectric actuator 11. In addition, the simplified design in the embodiment of the utility model can also reduce costs, improve the overall efficiency of the system and the flexibility of application.

[0039] In the embodiment of the utility model, the thermostatic element 12 can be a heating element or a cooling element. For the heating element, a positive temperature coefficient PTC material can be used. In the specific implementation process, combined with the PTC driving voltage limit, it can effectively prevent overheating and spontaneous combustion after loss of control. In order to ensure heat transfer efficiency and response speed, the heating element can use a polymer PTC material as a coating, which is directly coated on the surface of the actuator.

[0040] In the embodiment of the utility model, Figure 4 As shown, the housing 10 can adopt an encapsulated heat-insulating structure, the piezoelectric actuator 11 is fixed inside the housing 10 through a support structure 15 with low thermal conductivity, the housing 10 is sealed by a vacuum 18, and the inner wall 16 of the housing can be processed into a mirror surface. A thermostatic element 12 is arranged on the piezoelectric actuator 11, and the thermostatic element 12 can be a PTC heating layer or other cooling element. The outer layer of the housing 10 is provided with a heat-insulating layer 17. In the specific implementation process, the heat-insulating layer 17 can be wrapped with a material with low thermal conductivity.

[0041] In the embodiment of the utility model, the scanning display device can increase the internal and external thermal resistance of the device, reduce the sensitivity of the internal device to the external ambient temperature, reduce the external heat dissipation power, and the device heating power consumption through measures such as vacuum packaging, inner wall 16 reflection, and setting insulation material on the outer shell 10.

[0042] In the embodiments of the utility model, additional limiting protection measures can be added to prevent the device from overheating when out of control. For example, measures such as limiting the maximum power and maximum temperature of the heating element can be adopted. When PTC is used as the heating material, the risk of overheating when out of control can be effectively avoided. Furthermore, when the internal temperature of the device is set to be higher than the maximum rated operating environment temperature, the dual measures of the PTC heating material characteristics ensure that there is no risk of overheating and self-ignition when the device is out of control. In other embodiments, the heating material can also be used in conjunction with a temperature sensor for temperature control.

[0043] Based on the same utility model concept, the utility model embodiment further provides a scanning display module. Various specific methods of the scanning display module have been described in detail in the above-mentioned embodiments of the piezoelectric scanning device, and will not be elaborated here.

[0044] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0045] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0046] The present invention is not limited to the above-mentioned specific implementation modes, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A piezoelectric scanning device, characterized in that: include: Piezoelectric actuators; A constant temperature element is arranged on the surface of the piezoelectric actuator, and the constant temperature element is used to perform temperature compensation on the piezoelectric actuator during the scanning process of the piezoelectric actuator.

2. The piezoelectric scanning device according to claim 1, characterized in that: The piezoelectric actuator is a sheet-like structure, and the constant temperature element is arranged on the upper surface and / or the lower surface of the piezoelectric actuator.

3. The piezoelectric scanning device according to claim 1, characterized in that: The constant temperature element is a TEC semiconductor device.

4. The piezoelectric scanning device according to claim 1, characterized in that: The thermostatic element is a heating element.

5. The piezoelectric scanning device according to claim 4, characterized in that: The material of the heating element is a positive temperature coefficient PTC material.

6. The piezoelectric scanning device according to claim 5, characterized in that: The PTC material is disposed on the surface of the piezoelectric actuator by coating.

7. A scanning display module, characterized in that: include: A housing and a piezoelectric scanning device according to any one of claims 1 to 6; The piezoelectric actuator is fixed inside the housing via a supporting structure.

8. The scanning display module according to claim 7, characterized in that: The shell is a vacuum sealing structure.

9. The scanning display module according to claim 7, characterized in that: The outer surface of the shell is provided with a heat insulation layer.

10. The scanning display module according to claim 7, characterized in that: The inner surface of the shell is a mirror surface.

Images