Scanning actuator and scanning display module

Abstract

The invention discloses a scanning actuator and a scanning display module. The scanning actuator comprises a base, a fast axis actuating part, an adapter and a slow axis actuating part which are sequentially arranged from back to front. The adapter is connected with the base through a middle beam; the rear end of the slow shaft actuating part is connected with the adapter; the fast axis actuating part comprises a first piezoelectric actuating part and a second piezoelectric actuating part which are arranged on the two sides of the middle beam. The first piezoelectric actuating part and the second piezoelectric actuating part can synchronously and reversely stretch out and draw back in the front-back direction. And the first piezoelectric actuating part and the second piezoelectric actuating part are respectively hinged with the adapter. When the scanning actuator vibrates, force in the front-back direction can be transmitted between the fast axis actuating part and the slow axis actuating part in a hinged mode, transmission of torsional force is limited, and therefore the coupling problem between the fast axis and the slow axis is relieved, the phenomenon that odd-row vertical lines and even-row vertical lines of a scanning track are split is avoided, and the projection display quality is improved.

Description

Technical Field

[0001] This invention relates to the field of projection display, and more particularly to a scanning actuator and a scanning display module. Background Technology

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

[0003] A grid-based FSD scanner generally refers to a device that achieves projection display through grid scanning. In general, the fast axis of a grid-based FSD scanner is directly connected to the slow axis. Regardless of whether the fast axis is located at the tail, end, or integral part of the slow axis, it is difficult to avoid the influence of the reaction force generated by the large-amplitude vibration of the slow axis on the vibration characteristics of the fast axis, which leads to the coupling problem between the fast and slow axes. When displaying grid images, the odd and even vertical lines of the scanning trajectory will fork. Summary of the Invention

[0004] The purpose of this invention is to provide a scanning actuator and a scanning display module to alleviate the influence of the reaction force generated by the large amplitude vibration of the slow axis of the existing grid-type FSD scanner on the vibration characteristics of the fast axis, which leads to the fast-slow axis coupling problem.

[0005] To achieve the above-mentioned objective, a first aspect of the present invention provides a scanning actuator, comprising a base, a fast-axis actuating part, a transition member, and a slow-axis actuating part arranged sequentially in a rear-to-front direction; the transition member is connected to the base via an intermediate beam; the rear end of the slow-axis actuating part is connected to the transition member; the fast-axis actuating part includes a first piezoelectric actuating part and a second piezoelectric actuating part disposed on both sides of the intermediate beam; the first piezoelectric actuating part and the second piezoelectric actuating part are capable of synchronously retracting in opposite directions in a front-to-back direction; the first piezoelectric actuating part and the second piezoelectric actuating part are respectively hinged to the transition member.

[0006] Optionally, the hinge method between the first piezoelectric actuator and the second piezoelectric actuator and the adapter is a point contact hinge.

[0007] Optionally, the first piezoelectric actuator and the second piezoelectric actuator are respectively connected to the adapter via steel balls, forming a spherical hinge at the connection point.

[0008] Optionally, the contact area at the connection between the first piezoelectric actuator and the adapter is smaller than the cross-sectional area of ​​the main body of the first piezoelectric actuator, thereby reducing the contact area between the first piezoelectric actuator and the adapter; the contact area at the connection between the second piezoelectric actuator and the adapter is smaller than the cross-sectional area of ​​the main body of the second piezoelectric actuator, thereby reducing the contact area between the second piezoelectric actuator and the adapter, so as to reduce the equivalent torsional stiffness at each connection and form an approximately spherical hinge.

[0009] Optionally, through grooves are provided on both sides of the intermediate beam near the adapter, such that the thickness of the beam at the groove is less than the thickness of the main body of the intermediate beam, forming a flexible hinge structure.

[0010] Optionally, the first piezoelectric actuator and the second piezoelectric actuator do not contact the intermediate beam.

[0011] Optionally, the rear end of the fast shaft actuator is connected to the base.

[0012] Optionally, the slow-axis actuation part is a piezoelectric sheet structure.

[0013] A second aspect of the present invention provides a scanning display module, including an optical fiber and a scanning actuator as described in the first aspect, wherein the optical fiber is fixed to the front end of the slow axis actuator.

[0014] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0015] In this embodiment of the invention, the scanning actuator includes a base, a fast-axis actuation part, an adapter, and a slow-axis actuation part. The adapter is connected to the base via a central beam. The rear end of the slow-axis actuation part is connected to the adapter. The fast-axis actuation part includes a first piezoelectric actuation part and a second piezoelectric actuation part disposed on both sides of the central beam. The first and second piezoelectric actuation parts are capable of synchronously retracting in opposite directions along the front-rear direction. The first and second piezoelectric actuation parts do not contact the central beam. The first and second piezoelectric actuation parts are respectively hinged to the adapter. When the scanning actuator vibrates, the hinged connection allows the fast-axis actuation part and the slow-axis actuation part to transmit forces along the front-rear direction and restricts the transmission of torsional forces, thereby alleviating the coupling problem between the fast and slow axes, preventing the odd and even vertical lines of the scanning trajectory from forking, and improving the projection display quality. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0017] Figure 1 A side view of a scanning actuator provided in an embodiment of the present invention;

[0018] Figure 2 A top view of a scanning actuator provided in an embodiment of the present invention;

[0019] Figure 3 This is a side view of the fast shaft actuator and the intermediate beam provided in an embodiment of the present invention;

[0020] Figure 4 This is a top view of the fast shaft actuator and the intermediate beam provided in an embodiment of the present invention;

[0021] Figure 5 A side view of a scanning actuator with a groove on the intermediate beam provided in an embodiment of the present invention;

[0022] Figure 6 A top view of a scanning actuator with a groove on the intermediate beam provided in an embodiment of the present invention;

[0023] Figure 7 A side view of the intermediate beam provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figures 1-4As shown, an embodiment of the present invention provides a scanning actuator, including a base 100, a fast-axis actuation part, a connector 102, and a slow-axis actuation part 103 arranged sequentially from back to front; the connector 102 is connected to the base 100 via an intermediate beam 104; the rear end of the slow-axis actuation part 103 is connected to the connector 102; the fast-axis actuation part includes a first piezoelectric actuation part 1010 and a second piezoelectric actuation part 1011 disposed on both sides of the intermediate beam 104; the first piezoelectric actuation part 1010 and the second piezoelectric actuation part 1011 do not contact the intermediate beam 104; the first piezoelectric actuation part 1010 and the second piezoelectric actuation part 1011 are respectively hinged to the connector 102.

[0026] Driven by the driving signal, the first piezoelectric actuator 1010 and the second piezoelectric actuator 1011 can synchronously extend and retract in opposite directions along the front-back direction, causing the front end of the fast axis actuator to vibrate at a high frequency in the horizontal left-right direction. Driven by the driving signal, the front end of the slow axis actuator 102 vibrates at a low frequency in the vertical direction. During the vibration of the scanning actuator, the fast axis actuator and the slow axis actuator 103 can transmit forces in the front-back direction through a hinge, while restricting the transmission of torsional forces.

[0027] In the above solution, since the first piezoelectric actuator 1010 and the second piezoelectric actuator 1011 are respectively hinged to the adapter 102, the fast axis actuator and the slow axis actuator 103 only transmit force in the front-back direction (axial direction) and do not transmit torsional force, thereby alleviating the coupling problem between the fast and slow axes (i.e., between the fast axis actuator and the slow axis actuator 103), avoiding the bifurcation of the odd and even vertical lines of the scanning trajectory, and thus improving the projection display quality.

[0028] In this embodiment of the invention, the rear end of the quick-axis actuator is connected to the base 100. The connection method between the front end of the quick-axis actuator and the adapter 102 includes, but is not limited to, the following connection methods.

[0029] In a first possible implementation, the hinge between the first piezoelectric actuator 1010 and the adapter 102 can be a point contact hinge. Similarly, the hinge between the second piezoelectric actuator 1011 and the adapter 102 can also be a point contact hinge.

[0030] In a second possible implementation, the first piezoelectric actuator 1010 and the second piezoelectric actuator 1011 are respectively connected to the adapter 102 via steel balls, forming a spherical hinge at the connection point. In this embodiment of the invention, the steel balls can be removed to further simplify the structure.

[0031] In a third possible implementation, the equivalent torsional stiffness of the structure at the connection point can be reduced by decreasing the contact area between the fast-axis actuator and the adapter 102, thus creating an approximate spherical hinge effect. Specifically, the contact area at the connection between the first piezoelectric actuator 1010 and the adapter 102 is smaller than the cross-sectional area of ​​the main body of the first piezoelectric actuator 1010, thereby reducing the contact area between the first piezoelectric actuator and the adapter. Similarly, the contact area at the connection between the second piezoelectric actuator 1011 and the adapter 102 is smaller than the cross-sectional area of ​​the main body of the second piezoelectric actuator 1011, thereby reducing the contact area between the second piezoelectric actuator 1011 and the adapter 102. This reduces the equivalent torsional stiffness of the structure at each connection point, thereby achieving an approximate spherical hinge effect.

[0032] In the fourth possible implementation, such as Figures 5-7 As shown, through grooves 105 are provided on both sides of the intermediate beam 104 near the adapter 102, so that the thickness of the beam at the groove 105 is less than the thickness of the main body of the intermediate beam 104. By reducing the thickness of the intermediate beam, the equivalent torsional stiffness of the structure is reduced, so that the torsional stiffness of the slow axis vibration plane is much higher than that of the fast axis vibration plane, thereby achieving the effect of an approximate flexible hinge structure.

[0033] In this embodiment of the invention, the rear end of the slow axis actuation part 103 is connected to the adapter 102. The slow axis actuation part 103 is a piezoelectric sheet structure, including a double piezoelectric sheet structure, a single piezoelectric sheet structure, or a piezoelectric stacked structure, etc.

[0034] In this embodiment of the invention, the adapter 102 is hinged so that it can only twist on the vibration plane of the fast shaft actuator, restricting it from twisting in other directions, especially on the vibration plane of the slow shaft actuator 103. In this way, when the slow shaft actuator 103 vibrates, the torsional reaction force at the root of the slow shaft actuator 103 is restricted by the connecting hinge and cannot be transmitted to the fast shaft actuator, thereby avoiding changes in the frequency characteristics of the fast shaft actuator due to changes in external stress, thus preventing fast and slow shaft coupling.

[0035] In the above solution, in addition to effectively reducing or eliminating the transmission of the root reaction force to the fast axis actuator when the slow axis actuator 103 vibrates, it can also reduce the transmission of the non-horizontal torsion of the fast axis actuator to the slow axis actuator 103 due to device tolerance, thereby reducing or eliminating the vertical line forking of the scanning trajectory caused by the fast and slow axis coupling problem.

[0036] In this embodiment of the invention, a preload screw can be added to the tail of the fast shaft actuator to eliminate end face misalignment caused by machining and assembly errors, increase preload force, and improve the output of piezoelectric materials (such as piezoelectric ceramics).

[0037] Based on the same inventive concept, this embodiment of the invention also provides a scanning display module, including an optical fiber and the scanning actuator in the above embodiment. Regarding the arrangement of the optical fiber, the end face of the slow axis actuator is fixed to the optical fiber, and the optical fiber is not rigidly fixed to the adapter and the fast axis actuator.

[0038] The scanning display module in this invention can be applied to various scenarios, including but not limited to AR (Augmented Reality) devices, laser TVs, laser projectors, vehicle-mounted projectors, etc. In these application scenarios, one scanning display module can be used for projection display, or multiple scanning display modules can be used in concert to display or splice multiple images. This invention does not limit this.

[0039] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0040] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0041] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A scanning actuator, characterized in that, The device includes a base, a fast-axis actuation part, an adapter, and a slow-axis actuation part arranged sequentially from back to front. The adapter is connected to the base via a central beam. The rear end of the slow-axis actuation part is connected to the adapter. The fast-axis actuation part includes a first piezoelectric actuation part and a second piezoelectric actuation part disposed on both sides of the central beam. The first and second piezoelectric actuation parts are capable of synchronously retracting in opposite directions in the front-back direction. The first and second piezoelectric actuation parts are respectively hinged to the adapter.

2. The scanning actuator as claimed in claim 1, characterized in that, The first piezoelectric actuator and the second piezoelectric actuator are hinged to the adapter in a point contact manner.

3. The scanning actuator as described in claim 2, characterized in that, The first piezoelectric actuator and the second piezoelectric actuator are respectively connected to the adapter via steel balls, forming a spherical hinge at the connection point.

4. The scanning actuator as claimed in claim 1, characterized in that, The contact area at the connection between the first piezoelectric actuator and the adapter is smaller than the cross-sectional area of ​​the main body of the first piezoelectric actuator, thereby reducing the contact area between the first piezoelectric actuator and the adapter; the contact area at the connection between the second piezoelectric actuator and the adapter is smaller than the cross-sectional area of ​​the main body of the second piezoelectric actuator, thereby reducing the contact area between the second piezoelectric actuator and the adapter, so as to reduce the equivalent torsional stiffness at each connection and form an approximately spherical hinge.

5. The scanning actuator as claimed in claim 1, characterized in that, The intermediate beam has through grooves on both sides near the adapter, so that the thickness of the beam at the groove is less than the thickness of the main body of the intermediate beam, forming a flexible hinge structure.

6. The scanning actuator as claimed in claim 1, characterized in that, The first piezoelectric actuator and the second piezoelectric actuator do not contact the intermediate beam.

7. The scanning actuator as claimed in claim 1, characterized in that, The rear end of the fast shaft actuator is connected to the base.

8. The scanning actuator as claimed in claim 1, characterized in that, The slow-axis actuation part is a piezoelectric sheet structure.

9. A scanning display module, characterized in that, It includes an optical fiber and a scanning actuator as described in any one of claims 1-8, wherein the optical fiber is fixed to the front end of the slow axis actuator.

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