Scanning actuator and scanning display module

Abstract

The utility model discloses a scanning actuator and a scanning display module, the scanning actuator comprises a fast axis actuating part and a slow axis actuating part, the fast axis actuating part and the slow axis actuating part both extend along the front and back direction, and the fast axis actuating part and the slow axis actuating part are arranged in a folding manner; the fast axis actuating part comprises a first actuating part and a first fast axis resonant beam which are arranged on the left side of the slow axis actuating part, and a second actuating part and a second fast axis resonant beam which are arranged on the right side of the slow axis actuating part; the first fast axis resonant beam and the second fast axis resonant beam are both connected with the slow axis actuating part; under the driving of a fast axis driving signal, the first actuating part and the second actuating part drive the first fast axis resonant beam and the second fast axis resonant beam to deform, so that the fast axis actuating part vibrates in the fast axis direction. According to the scheme, the fast axis actuating part and the slow axis actuating part are arranged in a folded mode, and the size of the scanning actuator can be reduced.

Description

Technical Field

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

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

[0003] A raster FSD scanner generally refers to a device that realizes projection display through raster scanning. The raster scanning device includes two scanning axes that can vibrate in two directions, a fast axis and a slow axis. In order to obtain a large swing amplitude of the slow axis, the slow axis actuator requires a piezoelectric ceramic sheet with a large size, which will increase the volume of the scanning device.

[0004] In some application scenarios, such as wearable devices and in-vehicle projection, etc., it is necessary to minimize the volume of the scanning device as much as possible. Therefore, how to reduce the volume of the scanner is an important issue in the structural design of the scanner. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a scanning actuator and a scanning display module for reducing the volume of the scanner.

[0006] To achieve the above-mentioned utility model purpose, in the first aspect of the embodiment of the utility model, a scanning actuator is provided, which includes a fast axis actuating part and a slow axis actuating part. Both the fast axis actuating part and the slow axis actuating part extend along the front-rear direction, and the fast axis actuating part and the slow axis actuating part are folded; the fast axis actuating part includes a first actuating part and a first fast axis resonant beam arranged on the left side of the slow axis actuating part, and a second actuating part and a second fast axis resonant beam arranged on the right side of the slow axis actuating part; both the first fast axis resonant beam and the second fast axis resonant beam are connected to the slow axis actuating part; under the drive of a fast axis drive signal, the first actuating part and the second actuating part drive the first fast axis resonant beam and the second fast axis resonant beam to generate deformation, so that the fast axis actuating part vibrates in the fast axis direction.

[0007] Optionally, the nonlinear characteristics of the materials used for the first fast axis resonant beam and the second fast axis resonant beam are less than the nonlinear characteristics of the materials used for the first actuating part and the second actuating part.

[0008] Optionally, the materials used for the first actuating part and the second actuating part are piezoelectric materials; the materials used for the first fast axis resonant beam and the second fast axis resonant beam are steel or copper.

[0009] Optionally, under the drive of the fast-axis drive signal, the first fast-axis resonant beam and the second fast-axis resonant beam are in a bending vibration mode.

[0010] Optionally, the resonant frequencies of the first fast-axis resonant beam and the second fast-axis resonant beam in the bending vibration mode are close to the fast-axis drive frequency.

[0011] Optionally, the slow-axis resonant frequency satisfies the following condition: (F pn +F pn+1 ) / 2≈F d ; where F pn and F pn+1 are respectively the slow-axis resonant frequency and the fast-axis resonant frequency closest to the fast-axis drive frequency on the frequency characteristic curve, and F d is the fast-axis drive frequency.

[0012] Optionally, the mass of the slow-axis actuating part is less than or equal to 1 / 2 of the mass of the fast-axis actuating part.

[0013] Optionally, the first actuating part and the first fast-axis resonant beam are arranged in sequence in the front-to-back direction, and the second actuating part and the second fast-axis resonant beam are arranged in sequence in the front-to-back direction.

[0014] Optionally, both the first actuating part and the second actuating part are sheet-like structures, and the first actuating part and the second actuating part are respectively arranged on the outer surfaces of the first fast-axis resonant beam and the second resonant beam.

[0015] Optionally, the first actuating part and the second actuating part are piezoelectric stacked ceramic blocks.

[0016] Optionally, the first fast-axis resonant beam and the second fast-axis resonant beam are connected to the slow-axis actuating part through a fast-slow axis connecting member.

[0017] Optionally, the scanning actuator includes a base, and the fixed ends of the first actuating part and the second actuating part are fixedly connected to the base.

[0018] A second aspect of the embodiments of the present invention provides a scanning display module, including an optical fiber and the scanning actuator as described in the first aspect, and the optical fiber is fixed on the slow-axis actuating part.

[0019] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0020] In the solution of the embodiments of the present invention, the scanning actuator includes a fast-axis actuating part and a slow-axis actuating part arranged in a folded manner. The fast-axis actuating part and the slow-axis actuating part are arranged in a folded manner, which can reduce the volume of the scanning actuator.

[0021] The fast-axis actuating part includes a first actuating part and a second actuating part, which are respectively arranged on both sides of the slow-axis actuating part. The two actuating parts are respectively connected to the slow-axis actuating part through two resonant beams, and the high-frequency vibration amplitude is provided by the two resonant beams. The above solution can alleviate the problem existing in the prior art that due to the non-linear characteristics of the piezoelectric ceramic material itself, the vibrations in the fast and slow axis directions will be coupled, resulting in non-linear trajectories. By avoiding the coupling of vibrations in the fast and slow axis directions, the problem of non-linear trajectories is improved, and the quality of the scanned image is enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings:

[0023] Figure 1 A side view of the scanning actuator provided by an embodiment of the present invention;

[0024] Figure 2 A top view of the scanning actuator provided by an embodiment of the present invention;

[0025] Figure 3 A simulation schematic diagram of the large deformation of the fast-axis resonant beam provided by an embodiment of the present invention;

[0026] Figure 4 A schematic diagram of the impedance curve provided by an embodiment of the present invention;

[0027] Figure 5 A simulation schematic diagram of the bending vibration mode of the slow-axis piezoelectric ceramic sheet in the horizontal direction provided by an embodiment of the present invention;

[0028] Figures 6 - 8 A schematic diagram of the structure of the base provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] Such as Figure 1 And Figure 2As shown, the scanning actuator includes a fast-axis actuator part 10 and a slow-axis actuator part 11. Both the fast-axis actuator part 10 and the slow-axis actuator part 11 extend in the front-rear direction, and the fast-axis actuator part 10 and the slow-axis actuator part 11 are arranged in a folded manner. The fast-axis actuator part 10 includes a first actuator part 101 and a first fast-axis resonant beam 102 disposed on the left side of the slow-axis actuator part 11, and a second actuator part 103 and a second fast-axis resonant beam 104 disposed on the right side of the slow-axis actuator part 11. Both the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104 are connected to the slow-axis actuator part 11. Driven by a fast-axis driving signal, the first actuator part 101 and the second actuator part 103 drive the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104 to deform, causing the fast-axis actuator part 10 to vibrate in the fast-axis direction.

[0031] In an embodiment of the present invention, the first actuator part 101, the second actuator part 103, and the slow-axis actuator part 11 can all be implemented by piezoelectric ceramics. Driven by a fast-axis driving signal, the first actuator part 101 and the second actuator part 103 expand and contract back and forth, and drive the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104 to generate bending deformation by pushing and pulling, swing in the horizontal direction (i.e., the fast-axis direction), and then drive the slow-axis actuator part 11 to vibrate in the horizontal direction, as Figure 3 shown, which is a simulation schematic diagram of large deformation of the fast-axis resonant beam provided by the embodiment of the present invention.

[0032] In an embodiment of the present invention, since both the first actuator part 101 and the second actuator part 103 can be piezoelectric ceramics, the fast-axis driving part 10 includes piezoelectric ceramics and fast-axis resonant beams (including the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104). Driven by the fast-axis driving signal, the fast-axis resonant beam is in a bending vibration mode, and the resonant frequency of the fast-axis resonant beam in the bending vibration mode in the fast-axis direction is close to the fast-axis driving frequency (i.e., the frequency of the fast-axis driving signal), enabling the fast-axis resonant beam to provide the high-frequency vibration amplitude required by the scanning actuator. For vibrating devices, vibration modes include telescopic vibration modes, torsional vibration modes, and bending vibration modes, etc. In this solution, the vibration mode of the fast-axis resonant beam generally refers to the bending vibration mode. In other embodiments, it may also be other types of vibration modes.

[0033] In an embodiment of the present invention, as Figure 1 shown, the first actuator part 101 and the first fast-axis resonant beam 102 can be arranged in the front-to-back direction. Similarly, the second actuator part 103 and the second fast-axis resonant beam 104 can also be arranged in the front-to-back direction. It should be noted that in an embodiment of the present invention, taking the connection end of the fast-axis resonant beam and the slow-axis actuator part 11 as the rear end, the front-to-back direction is Figure 2in the right-to-left direction. In other embodiments, both the first actuating portion 101 and the second actuating portion 103 are sheet-like structures, respectively disposed on the outer surfaces of the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104. For example, the piezoelectric ceramic sheet included in the first actuating portion 101 is pasted on the side surface of the first fast-axis resonant beam 102, and the piezoelectric ceramic sheet included in the second actuating portion 103 is pasted on the side surface of the second fast-axis resonant beam 104. In other embodiments, the first actuating portion 101 and the second actuating portion 103 may also adopt piezoelectric stacked ceramic blocks, so as to effectively increase the driving amplitude of the fast-axis actuating portion 10 and reduce the driving voltage of the fast-axis driving signal.

[0034] In the embodiment of the present invention, the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104 are connected to the slow-axis actuating portion 11 through the fast-slow axis connecting member 13.

[0035] For a scanning actuator, in order to obtain vibration in the fast-axis direction, the fast-axis actuator needs to be connected to the end or the tail of the slow-axis actuator, and the high-frequency vibration mechanical wave generated by the fast-axis actuator will inevitably pass through the slow-axis actuator. If the fast-axis driving frequency is close to the inherent high-order frequency of the piezoelectric ceramic, the slow-axis actuator will resonate. Due to the non-linear characteristics of the piezoelectric ceramic material itself, the vibrations in the fast-axis and slow-axis directions will be coupled, resulting in non-linear trajectories, which will cause problems such as fork and opening asymmetry in the scanned image. Among them, fork means that when displaying an image, the vertical lines are bent and the vertical lines displayed in odd and even rows do not coincide; opening asymmetry means that when displaying an image, at different positions of the slow axis of the scanning trajectory, the closing degree of the fast-axis trajectory is inconsistent, some areas are closed straight lines, and some areas are ellipses.

[0036] In order to alleviate the above problems, the non-linear characteristics of the materials used for the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104 are less than the non-linear characteristics of the materials used for the first actuating portion 101 and the second actuating portion 103. For example, if the first actuating portion 101 and the second actuating portion 103 adopt piezoelectric materials, the non-linear characteristics of the materials used for the fast-axis resonant beam are less than the non-linear characteristics of the piezoelectric materials. For example, the fast-axis resonant beam can adopt a metal material with small non-linearity, such as steel or copper. Similarly, if the first actuating portion 101 and the second actuating portion 103 adopt other types of materials, correspondingly, the non-linear characteristics of the materials used for the fast-axis resonant beam also need to be less than the non-linear characteristics of the above types of materials. In other embodiments, the non-linear characteristics of the materials used for the first fast-axis resonant beam 102 and the second fast-axis resonant beam 104 can also be much less than the non-linear characteristics of the materials used for the first actuating portion 101 and the second actuating portion 103. It should be noted that much less in the embodiments of the present invention generally means that the difference between the two compared objects is more than 10 times.

[0037] In the embodiment of the present utility model, in order to achieve a sufficiently large swing amplitude of the fast axis drive, structural resonance is required to amplify the deformation amount of the piezoelectric ceramic for driving the fast axis. In order to avoid the non-linear influence of the slow axis piezoelectric ceramic, the slow axis piezoelectric ceramic sheet can adopt any one of the following implementation manners or a combination of each implementation manner.

[0038] In a possible implementation manner, the size and mass of the slow axis piezoelectric ceramic sheet can be reduced, so as to reduce the moment of inertia of the slow axis actuating part 11. For example: the mass of the slow axis actuating part 11 can be less than or equal to 1 / 2 of the mass of the fast axis actuating part 10.

[0039] In another possible implementation manner, the size of the slow axis piezoelectric ceramic sheet can be adjusted so that the resonance frequency of the slow axis piezoelectric ceramic sheet is far from the fast axis drive frequency, and the resonance frequency of the slow axis drive part and the fast axis drive frequency satisfy the following conditions, (F pn +F pn+1 ) / 2≈F d , where F d is the fast axis drive frequency, F pn and F pn+1 are respectively a slow axis resonance frequency and a fast axis resonance frequency on the frequency characteristic curve that are closest to the fast axis drive frequency. Next, as Figure 4 shown, taking the frequency characteristic curve as an impedance curve as an example for illustration.

[0040] In the embodiment of the present utility model, the impedance curve can be measured by a corresponding test device (such as an impedance analyzer). During actual operation, the curve within a specific frequency range can be measured by setting the frequency boundary. Generally speaking, within a certain frequency range near the fast axis drive frequency F d , the fast axis actuating part 10 and the slow axis actuating part 11 will generate a frequency response to this F d , and the phenomenon reflected on the impedance curve is that peaks appear on the curve. In the embodiment of the present utility model, F pn and F pn+1 are respectively the slow axis resonance frequency and the fast axis resonance frequency on the frequency characteristic curve that are closest to the fast axis drive frequency.

[0041] As Figure 5 shown, it is the bending vibration mode of the slow axis piezoelectric ceramic sheet in the horizontal direction. The resonance frequency of the slow axis piezoelectric ceramic sheet corresponding to this bending vibration mode is far from the fast axis drive frequency. Therefore, by adjusting parameters such as the size and mass of the slow axis actuating part, so that the resonance frequency of the slow axis actuating part is far from the fast axis drive frequency, it can be realized that when the fast axis actuating part 10 is normally driven, the slow axis actuating part, that is, the slow axis piezoelectric ceramic sheet, will not show the deformation of the bending vibration mode as Figure 5 shown.

[0042] In the embodiment of the present utility model, asFigures 6 - 8 As shown, the scanning actuator includes a base 12, and the fixed ends of the first actuator part 101 and the second actuator part 103 are fixedly connected to the front end of the base 12. The free ends of the first actuator part 101 and the second actuator part 103 are respectively connected to corresponding fast-axis cantilever beams, and the fast-axis cantilever beams are connected to the fixed end of the slow-axis actuator part 11. The base 12 includes Figure 7 the shown main body 121 and Figure 8 the shown upper cover 122. A hole for the optical fiber to pass through is formed at the rear end of the main body 121.

[0043] Based on the same inventive concept, an embodiment of the present invention further provides a scanning display module, which includes an optical fiber and the scanning actuator in the above embodiment. For the setting of the optical fiber, the optical fiber can be fixed to the end face of the slow-axis actuator part, so that the slow-axis actuator part and the fast-axis actuator part jointly drive the optical fiber to swing in space.

[0044] The scanning display module in the embodiment of the present invention can be applied to various scenarios, including but not limited to AR (full English name: Augmented Reality; Chinese name: Augmented Reality) devices, laser TVs, laser projectors, vehicle-mounted projections, etc. In these application scenarios, one scanning display module can be used for projection display, or multiple scanning display modules can be used in cooperation for the display or tiled display of multiple pictures. The present invention does not limit this.

[0045] All the features disclosed in this specification, or all the steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

[0046] Any feature disclosed in this specification (including any additional claims, abstract, and drawings), unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically stated, each feature is only an example of a series of equivalent or similar features.

[0047] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new method or process step or any new combination disclosed.

Claims

1. A scanning actuator, characterized in that, It includes a fast-axis actuator and a slow-axis actuator. Both the fast-axis actuator and the slow-axis actuator extend in the front-rear direction, and the fast-axis actuator and the slow-axis actuator are arranged in a folded manner; the fast-axis actuator includes a first actuator and a first fast-axis resonant beam disposed on the left side of the slow-axis actuator, and a second actuator and a second fast-axis resonant beam disposed on the right side of the slow-axis actuator; both the first fast-axis resonant beam and the second fast-axis resonant beam are connected to the slow-axis actuator; under the drive of a fast-axis drive signal, the first actuator and the second actuator drive the first fast-axis resonant beam and the second fast-axis resonant beam to deform, so that the fast-axis actuator vibrates in the fast-axis direction.

2. The scanning actuator according to claim 1, wherein, The non-linear characteristics of the materials used for the first fast-axis resonant beam and the second fast-axis resonant beam are less than the non-linear characteristics of the materials used for the first actuator and the second actuator.

3. The scanning actuator according to claim 2, characterized in that, The materials used for the first actuator and the second actuator are piezoelectric materials; the materials used for the first fast-axis resonant beam and the second fast-axis resonant beam are steel or copper.

4. The scanning actuator according to claim 1, wherein, The mass of the slow-axis actuator is less than or equal to 1 / 2 of the mass of the fast-axis actuator.

5. The scanning actuator according to claim 1, characterized in that, The first actuator and the first fast-axis resonant beam are arranged in sequence in the front-to-back direction, and the second actuator and the second fast-axis resonant beam are arranged in sequence in the front-to-back direction.

6. The scanning actuator according to claim 1, wherein Both the first actuator and the second actuator are sheet-like structures, and the first actuator and the second actuator are respectively disposed on the outer surfaces of the first fast-axis resonant beam and the second fast-axis resonant beam.

7. The scanning actuator according to claim 1, wherein The first actuator and the second actuator are piezoelectric stacked ceramic blocks.

8. The scanning actuator according to claim 1, wherein The first fast-axis resonant beam and the second fast-axis resonant beam are connected to the slow-axis actuator through a fast-slow axis connecting member.

9. The scanning actuator according to claim 1, wherein The scanning actuator includes a base, and the fixed ends of the first actuator and the second actuator are fixedly connected to the base.

10. A scanning display module, characterized in that, It includes an optical fiber and the scanning actuator according to any one of claims 1-9, and the optical fiber is fixed on the slow-axis actuator.

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