CN214540232U

CN214540232U - Scanning actuator and optical fiber scanner

Info

Publication number: CN214540232U
Application number: CN202023342624.1U
Authority: CN
Inventors: 不公告发明人
Original assignee: Chengdu Idealsee Technology Co Ltd
Current assignee: Chengdu Idealsee Technology Co Ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-10-29
Anticipated expiration: 2030-12-31

Abstract

The utility model discloses a scanning actuator, including the first actuating part and the second actuating part that connect gradually, the second actuating part includes the piezoceramics base plate, has at least one side to be provided with the drive electrode pair in the left side and the right side of piezoceramics base plate, and the drive electrode pair is including setting up the upper electrode layer on piezoceramics base plate upper surface and setting up the lower electrode layer on piezoceramics base plate lower surface, and the part that the piezoceramics base plate is located between the drive electrode pair polarizes along the vertical direction; the free end of the first actuating part vibrates at least along the vertical direction relative to the fixed end of the first actuating part, and the fixed end of the piezoelectric ceramic substrate is fixedly connected with the free end of the first actuating part. Because the fast axis only has a single-layer piezoelectric ceramic substrate, the single-side expansion or double-side synchronous reverse expansion of the single-layer piezoelectric ceramic substrate only can cause the left and right vibration in the horizontal direction, the vibration component in the vertical direction is extremely small, and extra correction is not needed; the area of the high-frequency driving electrode is reduced, so that the driving power consumption is greatly reduced.

Description

Scanning actuator and optical fiber scanner

Technical Field

The utility model relates to a scanning display technology field especially relates to a scanning actuator and fiber scanner.

Background

Scanning display imaging is a new display technology, and can be used for various display scenes such as projection display, near-eye display and the like.

The scanning display imaging can be realized by a fiber scanner, in addition to a Digital Micromirror Device (DMD) which is widely used at present.

A typical fiber scanner configuration, as shown in fig. 1, mainly includes: a scanning actuator adopting a fast-slow axis structure, and an optical fiber for scanning light. The scanning actuator fixed on the base comprises a slow shaft, an isolation part and a fast shaft in sequence from back to front, wherein the optical fiber scanner does not need to be provided with the isolation part, the slow shaft is used for vibrating at a relatively slow frequency in a first direction (vertical direction, namely the Y-axis direction of a reference coordinate system in figure 1), the fast shaft is used for vibrating at a relatively fast frequency in a second direction (horizontal direction, namely the X-axis direction of the reference coordinate system in figure 1), the vibration of the slow shaft is accumulated on the fast shaft through the isolation part, or the vibration of the slow shaft is directly accumulated on the fast shaft in an embodiment without the isolation part, so that the optical fiber can be driven to perform two-dimensional scanning in the first direction and the second direction, two-dimensional grid type scanning is realized, and an image is projected.

When the optical fiber scanner is used for realizing large-screen display or splicing display, a large number of optical fiber scanners are generally required to work simultaneously, and images emitted by the optical fiber scanners are spliced on a display screen. At this time, a slight increase in power consumption of a single fiber scanner will cause a significant increase in overall power consumption, and thus the equipment cost, the use cost, the heat dissipation requirement and the like are all increased significantly. Therefore, how to reduce the power consumption of a single scanner becomes a technical problem to be solved urgently.

Meanwhile, whether the scanner is easy to manufacture, how consistent the scanner is produced in batches, and whether the scanner is convenient to accurately position and assemble also restrict the imaging quality. To obtain a stable scanning range and accurately control the scanning trajectory, the scanning trajectory of the fiber scanner needs to have precise consistency, and any mounting structure is not firm and has a position error, so that the vibration of the actuator becomes uncontrollable or generates a disordered vibration component. How to avoid uncontrolled or chaotic vibration components is also one of the important factors to improve the quality of the scan.

SUMMERY OF THE UTILITY MODEL

An embodiment of the present invention provides a scan actuator for at least solving the above-mentioned technical problem caused by power consumption rise.

In order to achieve the above object, a first aspect of the present invention provides a scanning actuator, comprising a first actuating portion and a second actuating portion connected in sequence, wherein the second actuating portion comprises a piezoelectric ceramic substrate, a fixed end and a free end are respectively disposed at front and rear ends of the piezoelectric ceramic substrate, a vertical direction is disposed at a thickness direction of the piezoelectric ceramic substrate, a driving electrode pair is disposed at least one of left and right sides of the piezoelectric ceramic substrate, the driving electrode pair comprises an upper electrode layer disposed on an upper surface of the piezoelectric ceramic substrate and a lower electrode layer disposed on a lower surface of the piezoelectric ceramic substrate, a portion of the piezoelectric ceramic substrate between the driving electrode pairs is polarized along the vertical direction, the first actuating portion is driven by a transverse vibration mode in a width direction of the plate structure, equivalent damping is larger, response bandwidth is wider, and nonlinear effect is smaller, when the scanner is manufactured, the frequency matching of the optical fiber and the actuator is easier, the adaptive interval is wider, the yield and the manufacturing efficiency of finished products are improved, and the consistency of the finished products is improved more easily;

the both ends of first actuating portion are stiff end and free end respectively, and the free end of first actuating portion vibrates along the vertical direction at least for its stiff end, the stiff end of piezoceramics base plate and the free end fixed connection of first actuating portion.

In a preferred embodiment, the second actuating part is a fast axis actuator, the first actuating part is a slow axis actuator, and the vibration frequency of the fast axis actuator is much higher than that of the slow axis actuator. The extension direction of the piezoelectric ceramic substrate of the fast axis actuator is parallel to the fast axis vibration direction, no other layer is arranged on two surfaces of the piezoelectric ceramic substrate except an electrode layer, and after the left electrode area and the right electrode area are divided, a single electrode pair is driven or two electrode pairs are driven reversely, so that horizontal vibration is realized. Because the fast axis only has a single-layer piezoelectric ceramic substrate, the single-side expansion of the single-layer piezoelectric ceramic substrate or the synchronous reverse expansion of the two sides only can cause the left and right vibration in the horizontal direction, the vibration component in the vertical direction is extremely small, the fast axis horizontal swing can be realized only by simple driving, and the extra correction is basically not needed. Meanwhile, the area of the high-frequency driving electrode is reduced, so that the capacitance of the driving electrode is reduced, and the driving power consumption is greatly reduced. Compared with the piezoelectric ceramic matrix with the tubular and other special-shaped three-dimensional structures, the flaky piezoelectric ceramic substrate is easier to realize compactness, uniform material, good consistency and high forming precision.

In a preferred embodiment, the second actuating part is a fast axis actuator, the first actuating part is a slow axis actuator, and the vibration frequency of the fast axis actuator is much higher than that of the slow axis actuator.

Optionally, in some embodiments of the present invention, a driving electrode pair is disposed on the left side of the piezoelectric ceramic substrate, the driving electrode pair is not disposed on the right side of the piezoelectric ceramic substrate, the driving electrode pair includes an upper electrode layer disposed on the left side of the upper surface of the piezoelectric ceramic substrate and a lower electrode layer disposed on the left side of the upper surface of the piezoelectric ceramic substrate, the upper electrode layer and the lower electrode layer are disposed opposite to each other, after a driving voltage is applied through the upper electrode layer and the lower electrode layer, the left side of the piezoelectric ceramic substrate is extended or shortened in a horizontal direction under the driving voltage, and when the left side of the piezoelectric ceramic substrate is extended in the horizontal direction under the driving voltage, a free end of the piezoelectric ceramic substrate is horizontally shifted to the right with respect to a fixed end; when the left side of the piezoelectric ceramic substrate is shortened in the horizontal direction by the driving voltage, the free end of the piezoelectric ceramic substrate is horizontally shifted leftward with respect to the fixed end.

In some other embodiments of the present invention, a driving electrode pair is disposed on the right side of the piezoelectric ceramic substrate, the driving electrode pair is not disposed on the left side of the piezoelectric ceramic substrate, the driving electrode pair includes an upper electrode layer disposed on the right side of the upper surface of the piezoelectric ceramic substrate and a lower electrode layer disposed on the right side of the upper surface of the piezoelectric ceramic substrate, the upper electrode layer and the lower electrode layer are disposed opposite to each other, after a driving voltage is applied through the upper electrode layer and the lower electrode layer, the right side of the piezoelectric ceramic substrate is extended or shortened in a horizontal direction under the driving voltage, and when the right side of the piezoelectric ceramic substrate is extended in the horizontal direction under the driving voltage, a free end of the piezoelectric ceramic substrate is horizontally shifted to the left with respect to a fixed end; when the right side of the piezoelectric ceramic substrate is shortened in the horizontal direction by the driving voltage, the free end of the piezoelectric ceramic substrate is horizontally shifted to the right with respect to the fixed end.

In some other embodiments of the present invention, the left side and the right side of the piezoelectric ceramic substrate are both provided with a driving electrode pair, the driving electrode pair on the left side includes a first upper electrode layer disposed on the left side of the upper surface of the piezoelectric ceramic substrate and a first lower electrode layer disposed on the left side of the lower surface of the piezoelectric ceramic substrate, the first upper electrode layer and the first lower electrode layer are oppositely disposed, and after a driving voltage is applied through the first upper electrode layer and the first lower electrode layer, the left side of the piezoelectric ceramic substrate is extended or shortened in the horizontal direction under the driving of the driving voltage;

the right driving electrode pair comprises a second upper electrode layer arranged on the right side of the upper surface of the piezoelectric ceramic substrate and a second lower electrode layer arranged on the right side of the lower surface of the piezoelectric ceramic substrate, the upper electrode layer and the lower electrode layer are arranged oppositely, and after driving voltage is applied through the upper electrode layer and the lower electrode layer, the right side of the piezoelectric ceramic substrate is driven by the driving voltage to extend or shorten along the horizontal direction;

at the same time, the stretching directions of the right side and the left side of the piezoelectric ceramic substrate are opposite, namely when the right side of the piezoelectric ceramic substrate stretches in the horizontal direction under the driving of the driving voltage, the left side of the piezoelectric ceramic substrate shortens in the horizontal direction under the driving of the driving voltage, so that the free end of the piezoelectric ceramic substrate horizontally shifts to the left relative to the fixed end; when the right side of the piezoelectric ceramic substrate is shortened in the horizontal direction by the driving voltage, the left side of the piezoelectric ceramic substrate is elongated in the horizontal direction by the driving voltage, and the free end of the piezoelectric ceramic substrate is horizontally shifted to the right with respect to the fixed end.

Alternatively, the first actuating portion may be any one of a unimorph actuator, a bimorph actuator, a piezoelectric material tube actuator, or a piezoelectric sheet drive actuator.

The piezoelectric material tube actuator comprises a piezoelectric material tube, wherein the outer surface of the piezoelectric material tube is provided with at least one pair of outer electrodes which are symmetrical relative to the axis of the piezoelectric material tube, and the inner surface of the piezoelectric material tube is provided with an inner electrode matched with the outer electrodes. So that when the inner electrode and the outer electrode are connected with an external driving device, the front end of the actuating part vibrates along the corresponding axis.

Each external electrode and each internal electrode of the piezoelectric material tube are connected with an external driving circuit so as to apply an alternating electric field to the piezoelectric material tube through each pair of matched external electrode and internal electrode. The piezoelectric material tube is polarized along the radial direction, each pair of outer electrodes which are symmetrical relative to the axial lead of the piezoelectric material tube and the inner electrodes which correspond to the outer electrodes drive the piezoelectric material tube to stretch in opposite directions at the same moment, namely when one outer electrode and the inner electrode in each pair of outer electrodes drive the piezoelectric material tube positioned in the range of the outer electrode to stretch, the other outer electrode and the inner electrode drive the piezoelectric material tube positioned in the range to synchronously shorten; and vice versa. When one end of the piezoelectric material tube is fixed, the other end of the piezoelectric material tube is a free end, and the synchronous stretching and stretching actions enable the free end of the piezoelectric material tube to vibrate along a direction perpendicular to the axis relative to the fixed end. When the outer surface of the piezoelectric material tube is provided with n pairs of outer electrodes symmetrical with respect to the axis of the piezoelectric material tube, the free end of the piezoelectric material tube may vibrate in n directions perpendicular to the axis with respect to the fixed end. As a preferred embodiment of such an embodiment, n is 1 or 2, and when n is 2, one pair of the outer electrodes symmetric about the axis of the piezoelectric material tube and the corresponding inner electrode drive the free end of the piezoelectric material tube to vibrate in a direction perpendicular to the axis with respect to the fixed end thereof, and the other pair of the outer electrodes symmetric about the axis of the piezoelectric material tube and the corresponding inner electrode drive the free end of the piezoelectric material tube to vibrate in another direction perpendicular to the axis, so that the piezoelectric material tube actuator has a correction function, and the final vibration direction thereof can be freely adjusted to overcome the distortion of the scanning track caused by errors in the mounting, machining and other processes.

As shown in fig. 9, the piezoelectric sheet driving actuator includes a base body having an axial direction as a front-back direction, at least one first piezoelectric sheet extending and retracting in the front-back direction is attached to a surface of the base body at intervals along a circumferential direction, when at least two first piezoelectric sheets are attached to the surface of the base body at intervals along the circumferential direction, any two first piezoelectric sheets may or may not be symmetric with respect to a center of the base body, two ends of the base body in the front-back direction are a fixed end and a free end, respectively, and the extension and retraction of the first piezoelectric sheets drives the free end of the base body to vibrate in a direction perpendicular to the front-back direction with respect to the fixed end. When the two first piezoelectric sheets are symmetrical about the center of the base body, the expansion and contraction directions of the two first piezoelectric sheets which are symmetrical about the center of the base body at any time are opposite, so that the two first piezoelectric sheets jointly drive the base body to vibrate along a direction vertical to the front-back direction; the first piezoelectric sheets, which are not symmetrical with respect to the center of the base, each drive the base to vibrate in a corresponding direction perpendicular to the front-rear direction. The surface of the base body can be provided with only one first piezoelectric sheet or only two first piezoelectric sheets relative to the center of the base body, so that the free end of the base body can vibrate along a direction perpendicular to the front-back direction; at least two first piezoelectric sheets which are not symmetrical about the center of the base body can be arranged, so that the free end of the base body can vibrate along a plurality of directions vertical to the front-back direction, the piezoelectric sheet driving actuator has a correction function, the final vibration direction can be freely adjusted, and the distortion of a scanning track caused by errors in mounting, machining and other processes can be overcome.

The first piezoelectric sheet comprises a piezoelectric material sheet, electrodes are arranged on the surface of the piezoelectric material sheet, which is in contact with the base body, and the surface opposite to the surface of the piezoelectric material sheet, and the piezoelectric material sheet is polarized along the direction perpendicular to the two surfaces, namely the piezoelectric material sheet is polarized along the thickness direction.

The section of the substrate can be any closed figure formed by straight lines and/or curves; for example, the cross section of the substrate can be square, round or oval.

The bimorph actuator comprises a middle isolation sheet extending along the front-back direction, a first piezoelectric material sheet parallel to the middle isolation sheet is arranged on one side of the middle isolation sheet, a second piezoelectric material sheet parallel to the middle isolation sheet is arranged on the other side of the middle isolation sheet, the first piezoelectric material sheet and the second piezoelectric material sheet are both provided with two first surfaces parallel to the middle isolation sheet, and a layer of electrode is uniformly distributed on the first surfaces of the first piezoelectric material sheet and the second piezoelectric material sheet. At this time, the electrodes of the first sheet of piezoelectric material and the second sheet of piezoelectric material may each be connected to an external drive circuit to apply an alternating electric field to the sheets of piezoelectric material through the electrodes. The first sheet of piezoelectric material elongates or shortens under the action of the alternating electric field applied from the electrodes, and the second sheet of piezoelectric material elongates or shortens under the action of the alternating electric field applied from the electrodes, with the directions of expansion and contraction of the first sheet of piezoelectric material and the second sheet of piezoelectric material being opposite at any one time. In some other embodiments, the bimorph actuator may not include a central spacer, but only include the first and second closely-spaced pieces of piezoelectric material, and optionally, as shown, the two pieces of piezoelectric material may share a common electrode, a layer of common electrode may be disposed between the first and second pieces of piezoelectric material, and a layer of electrode may be disposed on the surface of each of the first and second pieces of piezoelectric material to mate with the common electrode.

Because one end of the second actuating part is a fixed end, the synchronous reverse expansion and contraction of the first piezoelectric material sheet and the second piezoelectric material sheet can drive the free end of the actuating part to vibrate along the direction vertical to the middle isolation sheet relative to the fixed end of the actuating part.

The single-piezoelectric-piece actuator comprises a substrate extending in the front-back direction, a third piezoelectric material piece parallel to the substrate is arranged on one side of the substrate, the third piezoelectric material piece is provided with two second surfaces parallel to the substrate, and a layer of electrode is uniformly distributed on the second surfaces of the third piezoelectric material piece. The electrodes of the third patch of piezoelectric material may each be connected to an external drive circuit to apply an alternating electric field to the patches of piezoelectric material through the electrodes. The third sheet of piezoelectric material elongates or contracts under the action of the alternating electric field applied from the electrodes.

Since one end of the second actuator is a fixed end, the expansion and contraction of the third piezoelectric material piece can drive the free end of the actuator to vibrate in a direction perpendicular to the substrate relative to the fixed end of the actuator.

The invention provides a fiber scanner using the scanning actuator, which comprises any one of the scanning actuators and an optical fiber, wherein the optical fiber is fixedly connected with the free end of the first actuating part in a cantilever supporting mode, the light-emitting end of the optical fiber is taken as the front end, the front part of the optical fiber exceeds the free end of the first actuating part to form an optical fiber cantilever, and the part of the optical fiber, which is positioned at the rear side of the optical fiber cantilever, is fixedly connected with the first actuating part.

The motion trail of the free end of the first actuating part relative to the fixed end of the second actuating part is the composition of the vibration trails of the second actuating part and the first actuating part, and the vibration direction of the free end of the second actuating part relative to the fixed end of the second actuating part is perpendicular to the vibration direction of the free end of the first actuating part relative to the fixed end of the first actuating part, so that the fiber cantilever can perform Lissajous type scanning or grid type scanning under the driving of the piezoelectric actuator. Preferably, the natural frequency of the first actuating part is much greater than the natural frequency of the second actuating part, so as to meet the requirements of grid scanning and avoid resonance interference between the second actuating part and the first actuating part.

Further preferably, the scanning actuator and the optical fiber are fixedly packaged in a housing, and a fixed end of the second actuating portion is fixedly connected with the housing. Further optionally, a corresponding lens group (not shown in the figures) is further fixed at the light-emitting end of the package. When the optical fiber scanning device works, the optical fiber scanning device is driven by the electrode to drive the optical fiber cantilever to sweep at a set track and a set frequency, and meanwhile, the end face of the optical fiber cantilever emits light so as to project a corresponding image. The scanning methods herein include, but are not limited to: grid-type scanning, spiral-type scanning, lissajou-type scanning, and the like.

Of course, in some embodiments, the number of scanning fibers is at least one, and may be two or more, and is not limited herein.

The embodiment of the utility model provides an in one or more technical scheme, following technological effect or advantage have at least:

the extension direction of the piezoelectric ceramic substrate of the fast axis actuator is parallel to the fast axis vibration direction, no other layer is arranged on two surfaces of the piezoelectric ceramic substrate except an electrode layer, and after the left electrode area and the right electrode area are divided, a single electrode pair is driven or two electrode pairs are driven reversely, so that horizontal vibration is realized. Because the fast axis only has a single-layer piezoelectric ceramic substrate, the single-side expansion of the single-layer piezoelectric ceramic substrate or the synchronous reverse expansion of the two sides only can cause the left and right vibration in the horizontal direction, the vibration component in the vertical direction is extremely small, the fast axis horizontal swing can be realized only by simple driving, and the extra correction is basically not needed. Meanwhile, the area of the high-frequency driving electrode is reduced, so that the capacitance of the driving electrode is reduced, and the driving power consumption is greatly reduced. Compared with the piezoelectric ceramic matrix with the tubular and other special-shaped three-dimensional structures, the flaky piezoelectric ceramic substrate is easier to realize compactness, uniform material, good consistency and high forming precision.

Drawings

FIG. 1 is a schematic diagram of an exemplary fiber scanner of the prior art;

fig. 2a is a schematic structural diagram of an illustrative scanning display module according to an embodiment of the present invention;

FIG. 2b is a schematic diagram of a fiber scanner in the illustrative scanning display module of FIG. 2 a;

FIG. 3 is a schematic structural diagram of a scanning actuator and a fiber scanner according to the present invention;

fig. 4 is a schematic top view of the scanning actuator of the present invention;

fig. 5 is a schematic structural diagram of an embodiment of a second actuating portion of the scanning actuator according to the present invention;

fig. 6 is a schematic view of a vibration structure of a second actuating portion of the scanning actuator according to the present invention;

fig. 7 is a schematic structural diagram of another embodiment of a second actuating portion of the scanning actuator according to the present invention;

FIG. 8 is a schematic structural diagram of a third embodiment of a second actuating portion of a scanning actuator according to the present invention

Fig. 9 is a schematic structural diagram of an embodiment of a first actuating portion of the scanning actuator according to the present invention;

fig. 10 is a schematic structural diagram of another embodiment of a first actuating portion of a scanning actuator according to the present invention;

fig. 11 is a schematic structural diagram of a third embodiment of a first actuating portion of a scanning actuator according to the present invention;

fig. 12 is a schematic structural diagram of a fourth embodiment of a first actuating portion of a scanning actuator according to the present invention;

fig. 13 is a schematic structural diagram of a fifth embodiment of the first actuating portion of the scanning actuator according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Illustrative scanning display module

As shown in fig. 2a, an illustrative scanning display module according to the present application mainly includes:

the laser system comprises a processor 100, a laser group 110, a fiber scanner 120, a transmission fiber 130, a light source modulation circuit 140, a scanning driving circuit 150 and a beam combining unit 160. Wherein:

the processor 100 may be a Graphics Processing Unit (GPU), a Central Processing Unit (CPU), or other chips or circuits having a control function and an image Processing function, and is not limited in particular.

When the system works, the processor 100 may control the light source modulation circuit 140 to modulate the laser group 110 according to image data to be displayed, where the laser group 110 includes a plurality of monochromatic lasers, and the lasers emit light beams of different colors respectively. As shown in fig. 2a, three-color lasers of Red (R), Green (G) and Blue (B) can be specifically used in the laser group. The light beams emitted by the lasers in the laser group 110 are combined into a laser beam by the beam combining unit 160 and coupled into the transmission fiber 130.

The processor 100 can also control the scan driving circuit 150 to drive the fiber scanner 120 to scan out the light beam transmitted in the transmission fiber 130.

The light beam scanned and output by the fiber scanner 120 acts on a certain pixel point position on the medium surface, and forms a light spot on the pixel point position, so that the pixel point position is scanned. Under the action of the fiber scanner 120, the output end of the transmission fiber 130 scans according to a certain scanning track, so that the light beam moves to the corresponding pixel point position for scanning. During actual scanning, the light beam output by the transmission fiber 130 will form a light spot with corresponding image information (e.g., color, gray scale or brightness) at each pixel location. In a frame time, the light beam traverses each pixel position at a high enough speed to complete the scanning of a frame of image, and because the human eye observes the object and has the characteristic of 'visual residual', the human eye cannot perceive the movement of the light beam at each pixel position but sees a frame of complete image.

With continued reference to FIG. 2b, a specific configuration of the fiber scanner 120 is shown, which includes: an actuator 121, a fiber optic cantilever 122, a lens 123, a scanner enclosure 124, and a fixed component 125. The actuator 121 is fixed in the scanner package 124 by a fixing component 125, the transmission fiber 130 extends at a free end of the actuator 121 to form a fiber suspension 122 (also referred to as a scanning fiber), and when the scanning actuator 121 is driven by a scanning driving signal to vibrate in a vertical direction (the vertical direction is parallel to a Y axis in the reference coordinate system in fig. 2a and 2b, in this embodiment, the vertical direction may also be referred to as a first direction) and a horizontal direction (the horizontal direction is parallel to an X axis in the reference coordinate system in fig. 2a and 2b, in this embodiment, the horizontal direction may also be referred to as a second direction), and the front end of the fiber suspension 122 is driven by the scanning actuator 121 to sweep along a predetermined track and emit a light beam, and the emitted light beam can be scanned and imaged through the lens 123.

It should be noted that, in the embodiment of the present application, the rear end of the scanning actuator refers to an end of the scanning actuator that does not vibrate and is used as a fixed end, and may also be referred to as a fixed end; the front end of the scanning actuator is the other end of the scanning actuator opposite to the rear end, and can also be called as a free end, and is the most significant part of deformation and amplitude on the scanning actuator. The light-emitting end of the optical fiber cantilever may be referred to as a tip end of the optical fiber cantilever or a free end of the optical fiber cantilever. It should be understood that such description is not intended as a limitation on the present application.

The above-mentioned illustrative optical display module is an exemplary one, and in practical applications, the specific architecture of the optical display module is not limited to that shown in fig. 2a and 2b, and may be changed, for example: the light source modulation circuit 140 and the scan driving circuit 150 may be combined into a processing circuit; for another example: the processor 100 may be independent from the optical display module, rather than being a constituent unit in the optical display module, and so on, and for different variations, it is not described in detail here.

As mentioned above, a slight increase in the power consumption of a single fiber scanner will result in a significant increase in the overall power consumption, and therefore the equipment cost, the use cost, the heat dissipation requirement, etc. will all rise significantly. Therefore, how to reduce the power consumption of a single scanner becomes a technical problem to be solved urgently.

Therefore, the embodiment of the present invention provides a scanning actuator, as shown in fig. 3 and fig. 4, which includes a first actuating portion 1 and a second actuating portion 2 connected in sequence, as shown in fig. 5-fig. 8, the second actuating portion 2 includes a piezoelectric ceramic substrate 23, the front and rear ends of the piezoelectric ceramic substrate 23 are respectively a fixed end 21 and a free end 22, the thickness direction of the piezoelectric ceramic substrate 23 is a vertical direction, at least one of the left side and the right side of the piezoelectric ceramic substrate 23 is provided with a driving electrode pair, the driving electrode pair includes an upper electrode layer 24 disposed on the upper surface of the piezoelectric ceramic substrate 23 and a lower electrode layer 25 disposed on the lower surface of the piezoelectric ceramic substrate 23, the portion of the piezoelectric ceramic substrate 23 located between the driving electrode pair is polarized along the vertical direction, the first actuating portion is driven by a transverse vibration mode in the width direction of the plate structure, the equivalent damping is larger, the response bandwidth is wider, the nonlinear effect is smaller, so that the frequency matching of the optical fiber and the actuator is easier and the adaptation interval is wider when the scanner is manufactured, the yield and the manufacturing efficiency of finished products are improved, and the consistency of the finished products is improved more easily;

the both ends of first actuation portion 1 are stiff end 11 and free end 12 respectively, and the free end 11 of first actuation portion 1 vibrates along the vertical direction at least for its stiff end 12, the stiff end 21 of piezoceramics base plate 23 and the free end fixed connection of first actuation portion.

In a preferred embodiment, the second actuating part 2 is a fast axis actuator, the first actuating part 1 is a slow axis actuator, and the vibration frequency of the fast axis actuator is much higher than that of the slow axis actuator. The extension direction of the piezoelectric ceramic substrate 23 of the fast axis actuator is parallel to the fast axis vibration direction and parallel to the slow axis substrate, and meanwhile, no other layer is arranged on two surfaces of the piezoelectric ceramic substrate 23 except electrode layers, and after the left and right electrode areas are divided, a single electrode pair is driven or two electrode pairs are driven reversely, so that horizontal vibration is realized, as shown in fig. 6. Because the fast axis only has the single-layer piezoelectric ceramic substrate 23, the single-side expansion or double-side synchronous reverse expansion of the single-layer piezoelectric ceramic substrate 23 only can cause the left and right vibration in the horizontal direction, the vibration component in the vertical direction is extremely small, the fast axis horizontal swing can be realized only by simple driving, and extra correction is basically not needed. Meanwhile, the area of the high-frequency driving electrode is reduced, so that the capacitance of the driving electrode is reduced, and the driving power consumption is greatly reduced. Compared with the piezoelectric ceramic matrix with the tubular and other special-shaped three-dimensional structures, the flaky piezoelectric ceramic substrate 23 is easier to realize compactness, uniform in material, good in consistency and high in forming precision.

In a preferred embodiment, the second actuating part 2 is a fast axis actuator, the first actuating part 1 is a slow axis actuator, and the vibration frequency of the fast axis actuator 1 is much higher than that of the slow axis actuator 2.

Thus, optionally, in some embodiments of the present invention, as shown in fig. 5, a driving electrode pair is disposed on the left side of the piezoelectric ceramic substrate 23, and a driving electrode pair is not disposed on the right side of the piezoelectric ceramic substrate 23, where the driving electrode pair includes an upper electrode layer 24 disposed on the left side of the upper surface of the piezoelectric ceramic substrate 23 and a lower electrode layer 25 disposed on the left side of the upper surface of the piezoelectric ceramic substrate 23, the upper electrode layer 24 and the lower electrode layer 25 are disposed opposite to each other, after a driving voltage is applied through the upper electrode layer 24 and the lower electrode layer 25, the left side of the piezoelectric ceramic substrate 23 is extended or shortened in a horizontal direction under the driving voltage, and when the left side of the piezoelectric ceramic substrate 23 is extended in the horizontal direction under the driving voltage, the free end 22 of the piezoelectric ceramic substrate 23 is horizontally shifted to the right relative to the fixed end 21; when the left side of the piezoelectric ceramic substrate 23 is shortened in the horizontal direction by the driving voltage, the free end 22 of the piezoelectric ceramic substrate 23 is horizontally shifted leftward with respect to the fixed end 21.

In other embodiments of the present invention, as shown in fig. 7, a driving electrode pair is disposed on the right side of the piezoelectric ceramic substrate 23, and no driving electrode pair is disposed on the left side of the piezoelectric ceramic substrate 23, the driving electrode pair includes an upper electrode layer 24 disposed on the right side of the upper surface of the piezoelectric ceramic substrate 23 and a lower electrode layer 25 disposed on the right side of the upper surface of the piezoelectric ceramic substrate 23, the upper electrode layer 24 and the lower electrode layer 25 are disposed opposite to each other, after a driving voltage is applied through the upper electrode layer 24 and the lower electrode layer 25, the right side of the piezoelectric ceramic substrate 23 is extended or shortened in a horizontal direction under the driving voltage, and when the right side of the piezoelectric ceramic substrate 23 is extended in the horizontal direction under the driving voltage, the free end 22 of the piezoelectric ceramic substrate 23 is horizontally shifted to the left relative to the fixed end 21; when the right side of the piezoelectric ceramic substrate 23 is shortened in the horizontal direction by the driving voltage, the free end 22 of the piezoelectric ceramic substrate 23 is horizontally shifted to the right with respect to the fixed end 21.

In other embodiments of the present invention, as shown in fig. 8, the left and right sides of the piezoelectric ceramic substrate 23 are provided with driving electrode pairs, the driving electrode pair on the left side includes a first upper electrode layer 24 disposed on the left side of the upper surface of the piezoelectric ceramic substrate 23 and a first lower electrode layer 25 disposed on the left side of the lower surface of the piezoelectric ceramic substrate 23, the first upper electrode layer 24 and the first lower electrode layer 25 are disposed opposite to each other, and after a driving voltage is applied through the first upper electrode layer 24 and the first lower electrode layer 25, the left side of the piezoelectric ceramic substrate 23 is driven by the driving voltage to extend or shorten along a horizontal direction;

the right driving electrode pair comprises a second upper electrode layer 24 arranged on the right side of the upper surface of the piezoelectric ceramic substrate 23 and a second lower electrode layer 25 arranged on the right side of the lower surface of the piezoelectric ceramic substrate 23, the upper electrode layer 24 and the lower electrode layer 25 are oppositely arranged, and after driving voltage is applied through the upper electrode layer 24 and the lower electrode layer 25, the right side of the piezoelectric ceramic substrate 23 is extended or shortened along the horizontal direction under the driving of the driving voltage;

at the same time, the expansion and contraction directions of the right and left sides of the piezoelectric ceramic substrate 23 are opposite, that is, when the right side of the piezoelectric ceramic substrate 23 is expanded in the horizontal direction by the driving voltage, the left side of the piezoelectric ceramic substrate 23 is shortened in the horizontal direction by the driving voltage, so that the free end 22 of the piezoelectric ceramic substrate 23 is horizontally shifted to the left with respect to the fixed end 21; when the right side of the piezoelectric ceramic substrate 23 is shortened in the horizontal direction by the driving voltage, the left side of the piezoelectric ceramic substrate 23 is elongated in the horizontal direction by the driving voltage, and the free end 22 of the piezoelectric ceramic substrate 23 is shifted horizontally to the right with respect to the fixed end 21.

Alternatively, the first actuating portion 1 may be any one of a unimorph actuator, a bimorph actuator, a piezoelectric material tube actuator, or a piezoelectric sheet-driven actuator.

As shown in fig. 9, the piezoelectric tube actuator includes a piezoelectric tube 111, an outer surface of the piezoelectric tube 111 is provided with at least one pair of outer electrodes 112 symmetrical with respect to an axial center of the piezoelectric tube 111, and an inner surface of the piezoelectric tube 111 is provided with an inner electrode 113 fitted to the outer electrodes 112. So that the front end of the actuator vibrates along its corresponding axis when the inner electrode 113 and the outer electrode 112 are connected to an external driving device.

Each of the outer electrode 112 and the inner electrode 113 of the piezoelectric material tube 111 is connected to an external driving circuit to apply an alternating electric field to the piezoelectric material tube 111 through each pair of the mating outer electrode 112 and inner electrode 113. The piezoelectric material tube 111 is polarized along the radial direction, each pair of outer electrodes 112 symmetrical with respect to the axial center of the piezoelectric material tube 111 and the corresponding inner electrode 113 drive the piezoelectric material tube 111 to expand and contract in opposite directions at the same time, that is, when one outer electrode 112 and the inner electrode 113 in each pair of outer electrodes 112 drive the piezoelectric material tube 111 located in the range to expand, the other outer electrode 112 and the inner electrode 113 drive the piezoelectric material tube 111 located in the range to synchronously contract; and vice versa. When one end of the piezoelectric material tube 111 is fixed, the other end of the piezoelectric material tube 111 is a free end, and the synchronous extension and contraction causes the free end of the piezoelectric material tube 111 to vibrate in a direction perpendicular to the axis relative to the fixed end. When the outer surface of the piezoelectric material tube 111 is provided with n pairs of outer electrodes 112 symmetrical with respect to the axis of the piezoelectric material tube 111, the free end of the piezoelectric material tube 111 may vibrate in n directions perpendicular to the axis with respect to the fixed end. As a preferred embodiment of such an embodiment, n is 1 or 2, and when n is 2, one pair of the outer electrode 112 symmetric about the axis of the piezoelectric material tube 111 and the corresponding inner electrode 113 drives the free end of the piezoelectric material tube 111 to vibrate in a direction perpendicular to the axis with respect to the fixed end thereof, and the other pair of the outer electrode 112 symmetric about the axis of the piezoelectric material tube 111 and the corresponding inner electrode 113 drives the free end of the piezoelectric material tube 111 to vibrate in another direction perpendicular to the axis, so that the piezoelectric material tube actuator has a correction function, and the final vibration direction thereof can be freely adjusted to overcome the distortion of the scanning track caused by the errors in the mounting, machining and other processes.

As shown in fig. 10, the piezoelectric sheet driving actuator includes a base 221 having an axial direction as a front-back direction, at least one first piezoelectric sheet 222 that expands and contracts in the front-back direction is attached to a surface of the base 221 at intervals in a circumferential direction, when at least two first piezoelectric sheets 222 are attached to the surface of the base 221 at intervals in the circumferential direction, any two first piezoelectric sheets 222 may or may not be symmetric with respect to a center of the base 221, two ends of the base 221 in the front-back direction are a fixed end and a free end, respectively, and the free end of the first piezoelectric sheet 222 that expands and contracts drives the base 221 to vibrate in a direction perpendicular to the front-back direction with respect to the fixed end. When the two first piezoelectric sheets 222 are symmetrical about the center of the base 221, the expansion and contraction directions of the two first piezoelectric sheets 222 symmetrical about the center of the base 221 at any one time are opposite, so that the two first piezoelectric sheets 222 drive the base 221 to vibrate in a direction perpendicular to the front-back direction; the first piezoelectric sheets 222, which are not symmetrical with respect to the center of the base 221, each drive the base 221 to vibrate in a corresponding direction perpendicular to the front-rear direction. The surface of the base 221 may be provided with only one first piezoelectric sheet 222 or only two first piezoelectric sheets 222 with respect to the center of the base 221, so that the free end of the base 221 may vibrate in a direction perpendicular to the front-rear direction; at least two first piezoelectric sheets 222 that are not symmetrical with respect to the center of the base 221 may be provided, so that the free end of the base 221 may vibrate in a plurality of directions perpendicular to the front-rear direction, and the piezoelectric sheet driving actuator may have a correction function, and the final vibration direction thereof may be freely adjusted to overcome distortion of a scanning path due to errors in mounting, machining, and the like.

The first piezoelectric sheet 222 includes a sheet of piezoelectric material, and a surface of the piezoelectric sheet contacting the base 221 and a surface opposite to the surface are both provided with electrodes, and the sheet of piezoelectric material is polarized in a direction perpendicular to the two surfaces, that is, the sheet of piezoelectric material is polarized in a thickness direction.

The cross section of the substrate 221 can be any closed figure formed by straight lines and/or curved lines; for example, the cross section of the substrate 221 may be square, circular or elliptical.

As shown in fig. 11, the bimorph actuator includes a middle spacer 231 extending in the front-rear direction, one side of the middle spacer 231 is provided with a first piezoelectric material piece 232 parallel to the middle spacer 231, the other side of the middle spacer 231 is provided with a second piezoelectric material piece 233 parallel to the middle spacer 231, the first piezoelectric material piece 232 and the second piezoelectric material piece 233 each have two first surfaces parallel to the middle spacer 231, and the first surfaces of the first piezoelectric material piece 232 and the second piezoelectric material piece 233 are each provided with a layer of electrode 234. The electrodes 234 of the first sheet 232 and the second sheet 233 of piezoelectric material may each be connected to an external drive circuit at this time to apply an alternating electric field to the sheets of piezoelectric material through the electrodes 234. The first piezoelectric material piece 232 is elongated or shortened by the alternating electric field applied from the electrode 234, and the second piezoelectric material piece 233 is elongated or shortened by the alternating electric field applied from the electrode 234, and the expansion and contraction directions of the first piezoelectric material piece 232 and the second piezoelectric material piece 233 are opposite at any one time. In some other embodiments, the bimorph actuator may not include a central spacer, but only include the first 232 and second 233 closely adjacent piezoelectric material pieces, as shown in fig. 11, in which case optionally, both piezoelectric material pieces may share a common electrode, as shown in fig. 12.

Since one end of the second actuator 2 is a fixed end, the synchronous reverse expansion and contraction of the first sheet 232 and the second sheet 233 of piezoelectric material drives the free end of the actuator to vibrate in a direction perpendicular to the middle spacer 231 relative to the fixed end thereof.

As shown in fig. 13, the single piezoelectric patch actuator includes a substrate 241 extending in a front-back direction, a third piezoelectric material patch 242 parallel to the substrate 241 is disposed on one side of the substrate 241, the third piezoelectric material patch 242 has two second surfaces parallel to the substrate, and a layer of electrode 243 is disposed on each of the second surfaces of the third piezoelectric material patch. The electrodes 243 of the third sheet 242 of piezoelectric material may each be connected to an external drive circuit to apply an alternating electric field to the sheets of piezoelectric material through the electrodes. The third patch 242 of piezoelectric material elongates or contracts under the influence of the alternating electric field applied from the electrodes.

Since one end of the second actuator 2 is a fixed end, the expansion and contraction of the third piece of piezoelectric material drives the free end of the actuator to vibrate in a direction perpendicular to the substrate relative to the fixed end.

A second aspect of the present invention provides an optical fiber scanner using the scanning actuator, as shown in fig. 3, which includes any one of the scanning actuators and an optical fiber, wherein the optical fiber is fixedly connected to a free end of the first actuating portion 2 in a cantilever-supported manner, a light-emitting end of the optical fiber is used as a front end, a free end of the optical fiber, which is beyond the first actuating portion 2, of the front portion of the optical fiber forms an optical fiber cantilever 3, and a portion of the optical fiber, which is located at the rear side of the optical fiber cantilever 3, is fixedly connected to the first actuating portion 2.

The motion track of the free end of the first actuating part 2 relative to the fixed end of the second actuating part 1 is the composition of the vibration tracks of the second actuating part 1 and the first actuating part 2, and the vibration direction of the free end of the second actuating part 1 relative to the fixed end thereof is perpendicular to the vibration direction of the free end of the first actuating part 2 relative to the fixed end thereof, so that the fiber cantilever 3 can perform lissajous type scanning or grid type scanning under the driving of the piezoelectric actuator. Preferably, the natural frequency of the first actuator 2 is much higher than the natural frequency of the second actuator 1, so as to meet the requirements of grid scanning, and avoid resonance interference between the second actuator 1 and the first actuator 2.

Further preferably, the scanning actuator and the optical fiber are fixedly packaged in the housing 4, and the fixed end of the second actuator 1 is fixedly connected to the housing 4. Further optionally, a corresponding lens group (not shown in the figures) is further fixed at the light-emitting end of the package. When the optical fiber scanning device works, the optical fiber scanning device is driven by the electrode to drive the optical fiber cantilever 3 to sweep at a set track and a set frequency, and meanwhile, the end face of the optical fiber cantilever 3 emits light so as to project a corresponding image. The scanning methods herein include, but are not limited to: grid-type scanning, spiral-type scanning, lissajou-type scanning, and the like.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" or "comprises" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The use of the words first, second, third, etc. do not denote any order, but rather the words are to be construed as names.

All features disclosed in this specification, except features that are mutually exclusive, may be combined in any way.

Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

The present invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification, and to any novel method or process steps or any novel combination of features disclosed.

Claims

1. A scanning actuator is characterized by comprising a first actuating part and a second actuating part which are sequentially connected, wherein the second actuating part comprises a piezoelectric ceramic substrate, the front end and the rear end of the piezoelectric ceramic substrate are respectively a fixed end and a free end, the thickness direction of the piezoelectric ceramic substrate is taken as the vertical direction, at least one of the left side and the right side of the piezoelectric ceramic substrate is provided with a driving electrode pair, the driving electrode pair comprises an upper electrode layer arranged on the upper surface of the piezoelectric ceramic substrate and a lower electrode layer arranged on the lower surface of the piezoelectric ceramic substrate, and the part of the piezoelectric ceramic substrate, which is positioned between the driving electrode pairs, is polarized along the vertical direction; the both ends of first actuating portion are stiff end and free end respectively, and the free end of first actuating portion vibrates along the vertical direction at least for its stiff end, the stiff end of piezoceramics base plate and the free end fixed connection of first actuating portion.

2. A scanning actuator as claimed in claim 1, wherein the second actuating part is a fast axis actuator and the first actuating part is a slow axis actuator, the fast axis actuator having a substantially higher vibration frequency than the slow axis actuator.

3. The scan actuator as claimed in claim 1, wherein the left side of the piezoelectric ceramic substrate is provided with a driving electrode pair, the right side of the piezoelectric ceramic substrate is not provided with the driving electrode pair, the driving electrode pair comprises an upper electrode layer disposed on the left side of the upper surface of the piezoelectric ceramic substrate and a lower electrode layer disposed on the left side of the upper surface of the piezoelectric ceramic substrate, the upper electrode layer and the lower electrode layer are disposed opposite to each other, and the left side of the piezoelectric ceramic substrate is extended or shortened in a horizontal direction by the driving voltage after the driving voltage is applied through the upper electrode layer and the lower electrode layer.

4. The scan actuator as claimed in claim 1, wherein the driving electrode pair is disposed on the right side of the piezoelectric ceramic substrate, the driving electrode pair is not disposed on the left side of the piezoelectric ceramic substrate, the driving electrode pair includes an upper electrode layer disposed on the right side of the upper surface of the piezoelectric ceramic substrate and a lower electrode layer disposed on the right side of the upper surface of the piezoelectric ceramic substrate, the upper electrode layer and the lower electrode layer are disposed opposite to each other, and the right side of the piezoelectric ceramic substrate is extended or shortened in a horizontal direction by the driving voltage after the driving voltage is applied through the upper electrode layer and the lower electrode layer.

5. The scan actuator as claimed in claim 1, wherein the left side and the right side of the piezoelectric ceramic substrate are provided with a driving electrode pair, the driving electrode pair on the left side comprises a first upper electrode layer disposed on the left side of the upper surface of the piezoelectric ceramic substrate and a first lower electrode layer disposed on the left side of the lower surface of the piezoelectric ceramic substrate, the first upper electrode layer and the first lower electrode layer are disposed opposite to each other, and after a driving voltage is applied through the first upper electrode layer and the first lower electrode layer, the left side of the piezoelectric ceramic substrate is extended or shortened in a horizontal direction under the driving of the driving voltage;

at the same time, the expansion and contraction directions of the right side and the left side of the piezoelectric ceramic substrate are opposite.

6. The scan actuator of claim 1, wherein the first actuating portion is a unimorph actuator or a bimorph actuator,

the single-piezoelectric-piece actuator comprises a substrate extending in the front-back direction, a third piezoelectric material piece parallel to the substrate is arranged on one side of the substrate, the third piezoelectric material piece is provided with two second surfaces parallel to the substrate, and a layer of electrode is uniformly distributed on the second surfaces of the third piezoelectric material piece;

the bimorph actuator comprises a middle spacer extending along the front-back direction, a first piezoelectric material sheet parallel to the middle spacer is arranged on one side of the middle spacer, a second piezoelectric material sheet parallel to the middle spacer is arranged on the other side of the middle spacer, the first piezoelectric material sheet and the second piezoelectric material sheet are both provided with two first surfaces parallel to the middle spacer, a layer of electrode is uniformly distributed on the first surfaces of the first piezoelectric material sheet and the second piezoelectric material sheet,

or the bimorph actuator comprises a first piezoelectric material sheet and a second piezoelectric material sheet which are tightly attached, a layer of common electrode is arranged between the first piezoelectric material sheet and the second piezoelectric material sheet, and a layer of electrode matched with the common electrode is arranged on the surfaces of the first piezoelectric material sheet and the second piezoelectric material sheet.

7. The scan actuator as claimed in claim 1, wherein the first actuating portion is a piezo tube actuator, the piezo tube actuator includes a piezo tube, an outer surface of the piezo tube is provided with at least one pair of outer electrodes symmetrical with respect to an axial center of the piezo tube, and an inner surface of the piezo tube is provided with inner electrodes matching with the outer electrodes.

8. The scan actuator of claim 1, wherein the first actuating portion is a piezoelectric tube actuator or a piezoelectric sheet driving actuator, the piezoelectric sheet driving actuator includes a base body having an axial direction as a front-back direction, and at least one first piezoelectric sheet extending and contracting in the front-back direction is attached to a surface of the base body at intervals along a circumferential direction.

9. An optical fiber scanner, comprising a scanning actuator according to any one of claims 1 to 8, and an optical fiber, wherein the optical fiber is fixedly connected with the free end of the first actuating portion in a cantilever-supported manner, the free end of the optical fiber, which is beyond the light-emitting end of the optical fiber, is used as a front end, a fiber cantilever is formed by the front portion of the optical fiber, and the portion of the optical fiber, which is located at the rear side of the fiber cantilever, is fixedly connected with the first actuating portion.

10. The fiber optic scanner of claim 9, wherein the scanning actuator and the fiber are fixedly housed in a housing, and a fixed end of the second actuator portion is fixedly connected to the housing.