Method and system for multi-component linking for fiber optic scanning displays

Abstract

A multi-element fiber scanner for scanning electromagnetic imaging radiation includes: a base having a base plane and a longitudinal axis orthogonal to the base plane; and a first fiber link that passes through the base in a direction parallel to the longitudinal axis. The first fiber link is operably coupled to at least one electromagnetic radiation source. The multi-element fiber scanner also includes a plurality of additional links connected to the base and extending from the base, and a retaining washer disposed at a predetermined distance from the base along the longitudinal axis. The first fiber link and the plurality of fiber links are connected to the retaining washer.

Description

[0001] This application is a divisional application of the patent application with international application number PCT / US2017 / 067982, international application date December 21, 2017, Chinese national application number 201780079676.6, and title “Method and system for multi-component linking for fiber optic scanning display”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62 / 438,415, filed on December 22, 2016, entitled “Method and Systems for Multi-Element Linkage for Fiber Scanning Display,” the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0004] The following conventional U.S. patent applications (including the present application) are filed concurrently, and the entire disclosures of the other applications are incorporated by reference into the present application for all purposes:

[0005] U.S. Patent Application Serial No. 15 / 851,005, filed on December 21, 2017, entitled “METHODS AND SYSTEMS FOR FABRICATION OF SHAPED FIBERELEMENTS FOR SCANNING FIBER DISPLAYS,” (Attorney Docket No. 101782-1060973-002210US);

[0006] U.S. Patent Application Serial No. 15 / 851,049, filed on December 21, 2017, entitled “METHODS AND SYSTEMS FOR FABRICATION OF SHAPED FIBER ELEMENTS USING LASER ABLATION,” (Attorney Docket No. 101782-1060976-002310US); and

[0007] U.S. patent application serial number 15 / 851,317, filed on December 21, 2017, (attorney docket number 101782-1060978-002410US), and entitled “METHODS AND SYSTEMS FOR MULTI-ELEMENT LINKAGE FOR FIBERSCANNING DISPLAY.” Technical Field

[0008] The present invention generally relates to methods and systems related to fiber scanning projection display systems. More specifically, embodiments of the present invention provide methods and systems for multi-element linking that enable scanning optical fibers to oscillate in a plane, in a group of planes, or along an arc. The present invention is suitable for various applications in computer vision and image display systems. Background Art

[0009] Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images, or portions thereof, are presented to a viewer in such a way that they appear real or can be perceived as real. Virtual reality or "VR" scenarios generally involve presenting digital or virtual image information in a manner that is opaque to other actual real-world visual input; augmented reality or "AR" scenarios generally involve presenting digital or virtual image information as an enhancement to a visualization of the real world around the viewer.

[0010] Despite these advances in display technology, there remains a need in the art for improved methods and systems related to augmented reality systems, and particularly display systems. Summary of the invention

[0011] According to an embodiment of the present invention, a multi-element fiber optic scanner for scanning electromagnetic imaging radiation is provided. The multi-element fiber optic scanner includes: a base having a base plane and a longitudinal axis orthogonal to the base plane; and a first fiber optic link, which passes through the base in a direction parallel to the longitudinal axis. The first fiber optic link is operably coupled to at least one electromagnetic radiation source. The multi-element fiber optic scanner also includes a plurality of additional links connected to the base and extending from the base, and a retaining washer arranged at a predetermined distance from the base along the longitudinal axis, wherein the first fiber optic link and the plurality of fiber optic links are connected to the retaining washer. The plurality of additional links can extend from the base in a direction substantially parallel to the longitudinal axis. During operation, the multi-element fiber optic scanner can scan electromagnetic imaging radiation along an axis parallel to the base plane.

[0012] According to another embodiment of the present invention, a method for manufacturing a multi-element fiber scanner is provided. The method includes providing a fiber optic cable having a cladding region and a core, and focusing a laser beam at a series of predetermined locations inside the cladding region of the fiber optic cable. The method also includes creating a plurality of damage sites at predetermined locations, exposing the fiber optic cable to an etchant solution, and preferentially etching the plurality of damage sites to form: a base having a base plane and a longitudinal axis orthogonal to the base plane; a retaining washer disposed a predetermined distance from the base along the longitudinal axis; a first fiber optic link including a core, passing through the base plane and connected to the retaining washer; and a plurality of additional links connected to the base, extending from the base to the retaining washer and connected to the retaining washer.

[0013] As an example, the method may further include rotating the optical fiber cable around the longitudinal axis during the creation of the plurality of damage sites at the predetermined locations. In addition, creating the plurality of damage sites at the predetermined locations may include forming a grid of damage sites, the grid of damage sites may include a plurality of radial through holes passing through the cladding region toward the core. In one embodiment, creating the plurality of damage sites at the predetermined locations includes first creating a first portion of the plurality of damage sites adjacent to the core, and then creating a second portion of the plurality of damage sites adjacent to the periphery of the cladding region. In addition to the optical fiber cladding and the core, the optical fiber cable may include a plurality of sacrificial regions disposed in the cladding region. The plurality of sacrificial regions may be air cavities, or may include a material having a higher etching rate than the cladding region.

[0014] According to a specific embodiment of the present invention, a method for manufacturing a multi-element fiber scanner is provided. The method includes manufacturing a preform including a structural precursor for at least one optical fiber waveguide, an optical fiber support and a sacrificial material, and drawing the preform to form an optical fiber structure. The method also includes exposing the optical fiber structure to an etchant solution and preferentially etching the sacrificial material to form: a base having a base plane and a longitudinal axis orthogonal to the base plane; a retaining washer, which is arranged at a predetermined distance from the base along the longitudinal axis; a first optical fiber link, which includes at least one optical fiber waveguide, passing through the base plane and connected to the retaining washer; and a plurality of optical fiber supports, which are connected to the base, extend from the base to the retaining washer and are connected to the retaining washer.

[0015] According to another specific embodiment of the present invention, a method of operating a multi-element fiber scanner is provided. The method includes providing an electromagnetic radiation source and directing electromagnetic radiation from the source through a first fiber link. The first fiber link passes through a base having a base plane and a longitudinal axis orthogonal to the base plane. The method also includes supporting a retaining washer disposed a predetermined distance from the base along the longitudinal axis. A plurality of additional links connect the base to the retaining washer. The method further includes translating the base in the base plane, translating the retaining washer in a set of planes parallel to the base plane, and scanning the electromagnetic radiation in one or more axes.

[0016] According to a specific embodiment of the present invention, a multi-element fiber optic scanner for scanning electromagnetic imaging radiation is provided. The multi-element fiber optic scanner includes: a base having a base plane and a longitudinal axis orthogonal to the base plane; and a first fiber optic link that passes through the base in a direction parallel to the longitudinal axis. The first fiber optic link is operably coupled to at least one electromagnetic radiation source. The multi-element fiber optic scanner also includes: a plurality of actuating elements that are connected to the base and extend from the base along the longitudinal axis; and a retaining washer that is disposed at a predetermined distance from the base along the longitudinal axis. The plurality of actuating elements can be arranged around the first fiber optic link. The first fiber optic link and the plurality of actuating elements are connected to the retaining washer. During operation, the first fiber optic link is operable to scan electromagnetic imaging radiation along an axis parallel to the base plane.

[0017] According to another specific embodiment of the present invention, a method of operating a multi-axis fiber scanner is provided. The method includes providing an electromagnetic radiation source and directing electromagnetic radiation from the source through a first fiber link. The first fiber link passes through a base having a base plane and a longitudinal axis orthogonal to the base plane. The method also includes supporting a retaining washer disposed at a predetermined distance from the base along the longitudinal axis. A plurality of piezoelectric actuators connect the base to the retaining washer. A first piezoelectric actuator of the plurality of piezoelectric actuators connects one side of the base to one side of the retaining washer. A second piezoelectric actuator of the plurality of piezoelectric actuators connects an opposite side of the base to an opposite side of the retaining washer. The first piezoelectric actuator and the second piezoelectric actuator are located in a scanning plane. The method further includes: actuating a first piezoelectric actuator of the plurality of piezoelectric actuators to reduce a distance from one side of the base to one side of the retaining washer; actuating a second piezoelectric actuator of the plurality of piezoelectric actuators to increase a distance from an opposite side of the base to an opposite side of the retaining washer; and scanning the first fiber link in the scanning plane. As described herein, the method may include alternately actuating a first piezoelectric actuator to decrease or increase a distance at one side between the base and the retaining washer while simultaneously alternatingly actuating a second piezoelectric actuator to increase or decrease a distance at a second side between the base and the retaining washer.

[0018] According to another embodiment of the present invention, a multi-element fiber scanner for scanning electromagnetic imaging radiation is provided. The multi-element fiber scanner includes: a base having a base plane and a longitudinal axis orthogonal to the base plane; and a first fiber link passing through the base in a direction parallel to the longitudinal axis. The first fiber link is operably coupled to at least one electromagnetic radiation source. The multi-element fiber scanner also includes a plurality of motion actuation links connected to the base and extending from the base. Each of the plurality of motion actuation links includes a first piezoelectric element proximate to the base and a second piezoelectric element coupled to the first piezoelectric element at a position away from the base. The multi-element fiber scanner further includes a retaining washer disposed at a predetermined distance from the base along the longitudinal axis. The first fiber link and the second piezoelectric element of each of the plurality of motion actuation links are connected to the retaining washer. During operation, the first piezoelectric element contracts / expands as the second piezoelectric element expands / contracts.

[0019] According to yet another embodiment of the present invention, a multi-element fiber scanner for scanning electromagnetic imaging radiation is provided. The multi-element fiber scanner includes: a base having a support surface defining a base plane, a mounting surface opposite the support surface, and a longitudinal axis orthogonal to the base plane; and a plurality of motion actuators coupled to the support surface of the base. The multi-element fiber scanner also includes a multi-link fiber structure coupled to the mounting surface. The multi-link fiber structure includes a fiber base and a fiber link passing through the fiber base in a direction parallel to the longitudinal axis. The fiber link is operably coupled to at least one electromagnetic radiation source. The multi-link fiber structure also includes: a plurality of motion actuator elements (e.g., piezoelectric actuators) connected to the fiber base and extending from the fiber base along the longitudinal axis; and a retaining washer disposed at a predetermined distance from the fiber base along the longitudinal axis. The fiber link and the plurality of motion actuator elements are connected to the retaining washer.

[0020] Many benefits are achieved by the present invention over conventional techniques. For example, embodiments of the present invention provide methods and systems for scanning a fiber support in a substantially planar manner, thereby providing an image field with a known profile. These and other embodiments of the present invention and their many advantages and features are described in more detail below and in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a simplified perspective view showing a multi-element fiber optic scanner according to an embodiment of the present invention.

[0022] Figure 2 is a simplified diagram showing two scanning positions of a multi-element fiber scanner according to an embodiment of the present invention.

[0023] Figure 3is a simplified diagram showing a multi-element fiber scanner with tilted links according to an embodiment of the present invention.

[0024] Figure 4 is a simplified diagram showing elements of a fiber optic scanning system according to an embodiment of the present invention.

[0025] Figure 5 is a simplified flow chart illustrating a method of manufacturing a multi-element fiber optic scanner according to an embodiment of the present invention.

[0026] Figure 6 is a simplified flow chart illustrating a method of manufacturing a multi-element fiber optic scanner according to another embodiment of the present invention.

[0027] Figure 7 is a simplified flow chart illustrating a method of operating a multi-element fiber optic scanner according to an embodiment of the present invention.

[0028] Fig. 8A is a simplified perspective view showing a multi-axis fiber scanner according to an embodiment of the present invention.

[0029] Figure 8B is a simplified flow chart illustrating a method of operating a multi-axis fiber scanner according to an embodiment of the present invention.

[0030] Fig. 9A is a simplified side view showing a multi-section motion actuation element according to an embodiment of the present invention.

[0031] Fig. 9B is a diagram showing an embodiment of the present invention Fig. 9A A simplified side view of the oscillatory motion of a multi-segment motion actuator is shown.

[0032] Fig. 9C is a diagram showing a method of performing the above-mentioned steps according to an embodiment of the present invention. Fig. 9A A simplified side view of a multi-element fiber optic scanner showing a multi-element motion actuation element.

[0033] Fig.9D is a simplified perspective view of a piezoelectric motion actuator according to an embodiment of the present invention.

[0034] Fig.9E is a simplified end view showing a multi-element motion actuator in accordance with an embodiment of the present invention.

[0035] Fig.9F is a simplified side view showing a multi-section motion actuation structure according to an embodiment of the present invention.

[0036] Fig.10 is a multi-element fiber optic scanner for scanning electromagnetic imaging radiation according to an embodiment of the present invention.

[0037] Fig.11 is a simplified side view of a fiber optic cable and a laser ablation beam according to an embodiment of the present invention.

[0038] Fig.12 is a simplified flow chart illustrating a method of manufacturing a multi-element fiber optic scanner according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] Embodiments of the present invention relate to methods and systems related to fiber scanning projection display systems. More specifically, embodiments of the present invention provide methods and systems for multi-element linking that enable scanning optical fibers to oscillate in a plane or along an arc. The present invention is applicable to various applications in computer vision and image display systems.

[0040] Figure 1 1 is a simplified perspective view showing a multi-element fiber scanner according to an embodiment of the present invention. The multi-element fiber scanner 100 can be used to scan electromagnetic imaging radiation to form an element of a display system. The multi-element fiber scanner includes a base 110, which can also be referred to as an actuator base. The base is disposed in a base plane and can be characterized by a longitudinal axis 112 orthogonal to the base plane.

[0041] The multi-element fiber scanner also includes a retaining collar 130 disposed a predetermined distance D from the base 110 along the longitudinal axis 112. In some embodiments, the retaining collar 130 is parallel to the base and orthogonal to the longitudinal axis. The area between the base 110 and the retaining collar 130 may be referred to as a support portion.

[0042] A first optical fiber link 114 (also referred to as a waveguide) passes through the base in a direction parallel to the longitudinal axis. The first optical fiber link 114 is operably coupled to at least one electromagnetic radiation source (not shown) so that modulated light can be directed through the first optical fiber link while the distal end of the optical fiber tip is mechanically scanned to generate an image, which can then be coupled through a display system. The first optical fiber link can be fixed to the base at the location where it passes through the base, or it can be free to move in the plane of the base. The first optical fiber link passes through a retaining washer and can be fixed to the retaining washer at the location where it passes through the retaining washer, or it can be free to move in the plane of the retaining washer and / or in a direction parallel to the longitudinal axis (i.e., axial direction). In some embodiments, the first optical fiber link passes through the retaining washer in a direction parallel to the longitudinal axis.

[0043] In an alternative embodiment, the first optical fiber link can be replaced by another optical waveguide structure that can be manufactured using a process other than the optical fiber drawing process, for example, using a micro-electromechanical system (MEMS) or micro-opto-electromechanical system (MOEMS) micromachining process. Therefore, molded parts and optical waveguides manufactured using additive manufacturing are included within the scope of the present invention, for example, cantilever structures, channel waveguides, etc. These optical waveguide structures can be made of a variety of materials, including silicon, silicon carbide, silicon oxide, silicon nitride, and combinations thereof, etc.

[0044] In addition to the first fiber link, a plurality of additional links 116 extend from the base. These additional links, which may be made of a glass material, are connected to the base at one end and to a retaining washer at the other end. As a result, the retaining washer is mechanically connected to the additional links. The plane in which the retaining washer is disposed can be considered as one of the planes in the set of motion planes, since the retaining washer oscillates as it moves through the set of planes. Figure 1 In the illustrated embodiment, a plurality of additional links are arranged around the first optical fiber link, but this is not required by the present invention. In other embodiments, the number of additional links and the location of each additional link are modified to suit a particular application. In addition, although Figure 1 The plurality of additional links shown extend from the base in a direction parallel to the longitudinal axis, but as with respect to Figure 3 As more fully described, this is not required by the present invention.

[0045] The additional link may provide only a mechanical function or may also provide an optical function. As an example, the additional link may be replaced with a piezoelectric element that can expand and contract to provide motion actuation. In these embodiments, one or more of the multiple additional links may be operably coupled to at least one electromagnetic radiation source or other electromagnetic radiation source and pass through a base parallel to the longitudinal axis and through a retaining washer. In these embodiments, modulated light may be transmitted through all optical fiber links that provide optical functions. It should be understood that the additional links may be manufactured in various ways and using various materials. Although some embodiments are described based on glass links manufactured from optical fibers, the present invention is not limited to this material or manufacturing method, and other materials and manufacturing processes may be used with respect to the additional links.

[0046] A multi-core fiber scanner provides an array of sources associated with multiple pixels that can be scanned to produce a display image with a multiplied resolution as a function of the number of sources. In some embodiments, one set of additional links is used for mechanical support, and another set is used as an additional light source to supplement the first fiber link. Therefore, embodiments of the present invention include implementations having the following aspects: a single core and mechanical supports (e.g., multiple peripheral supports), multiple cores and mechanical supports, and multiple cores that provide optical and mechanical functions. The mechanical support can be made of glass similar to the first core, or made of other suitable materials with sufficient flexibility and rigidity, including piezoelectric materials, metals, ceramics, polymers, etc. Those of ordinary skill in the art will recognize many variations, modifications, and substitutions.

[0047] In an alternative embodiment, multiple cores terminating at different longitudinal positions may be implemented in conjunction with the fiber scanner described herein. In this embodiment, the depth plane associated with each core may be varied to provide different signals at different depths.

[0048] refer to Figure 1 , the multi-element fiber scanner may also include a piezoelectric actuator 105 mechanically coupled to a base 110. The piezoelectric actuator is operable to translate the base in a base plane, for example, laterally in a direction 107 or in a transverse direction pointing into the plane of the drawing and pointing out of the plane of the drawing. As an example, the piezoelectric actuator 105 (which may also be referred to as a base) may include a plurality of piezoelectric elements that may contract and expand to appropriately produce the desired oscillations in the base. In an embodiment where the base is laterally translated, the first fiber link is scanned laterally in the plane of the drawing, and the electromagnetic imaging radiation is scanned along an axis parallel to the base plane. Light 115 emitted from the first fiber link is shown as light leaving the optical fiber 114.

[0049] Since the additional links are mechanically coupled to each other in the base plane and the plane of the retaining washer, movement of the base in the base plane (e.g., using movement of the piezoelectric actuator 105) will cause movement of the top of the additional link and the retaining washer in a plane group parallel to the plane of the retaining washer.

[0050] Figure 2 is a simplified diagram showing two scanning positions for a multi-element fiber scanner according to an embodiment of the present invention. Figure 2As shown, movement of the base 110 in the base plane will cause the retaining washer 130 to move horizontally (and in some embodiments vertically). Two positions of the retaining washer are shown, showing the ends of an exemplary range of motion. In a center position where the retaining washer is directly above the base, the retaining washer will be separated from the base by a greater vertical distance than in the illustrated position. However, for small angles (e.g., angles less than a few degrees), the change in distance between the base and the retaining washer will be small, resulting in movement of the retaining washer in essentially a single plane (which may be referred to as the plane of motion) parallel to the base plane. Due to the mechanical coupling of the top of the additional link to the retaining washer, the retaining washer remains parallel to the base plane as the additional fiber link tilts and / or bends in response to movement of the base. From an optical standpoint, Figure 2 The shearing motion shown is desirable because the image field associated with the first fiber link can be substantially flat (which is useful in a variety of optical configurations), or curved in a predetermined manner. Figure 2 Additional fiber links are shown, but embodiments of the present invention may utilize other materials and structures for additional links. As an example, MEMS structures may be used to provide the benefits inherent in embodiments of the present invention. Therefore, references to additional links, links, etc. should be understood to include MEMS structures, including but not limited to silicon flexures.

[0051] Figure 3 is a simplified diagram showing a multi-element fiber scanner with tilted links according to an embodiment of the present invention. Figure 3 A base 110 is provided to which the optical fiber links 310 and 312 are mechanically attached. An electromagnetic radiation source 330 (e.g., a diode laser or a light emitting diode) is optically coupled to the first optical fiber link 114. Figure 3 In the illustrated embodiment, the optical fiber link 312 is optically coupled to the electromagnetic radiation source 331. Thus, depending on the implementation, one or more of the plurality of additional links may pass through the base in a direction substantially parallel to the longitudinal axis and may be operably coupled to one or more electromagnetic radiation sources. The optical fiber link 310 extends from the base at an angle θ, and the optical fiber link 312 extends from the base at an opposite angle -θ, such that the two optical fiber links are angled toward the first optical fiber link 114. The optical fiber links 310 and 312 are mechanically coupled to the retaining washer 130. The first optical fiber link 114 may be fixed to the retaining washer, or may be a slip fit in the retaining washer.

[0052] Due to the tilt present in the fiber links 310 and 312, for small angles, e.g., less than about a few degrees, the movement of the retaining washer 130 (and the resulting fiber tip) will follow an arc 320 having a center that coincides with the intersection R of the lines extending from the fiber links. In other words, the radius of curvature of arc 320 is equal to r. Thus, the retaining washer in this configuration translates along a curved arc, which may also be referred to as the oscillating portion of the curve. As the retaining washer oscillates, light from the first fiber link 114 is emitted toward the intersection R at the center of the arc (which may be referred to as the focus). Thus, embodiments of the present invention move the transmitting fiber through a concave image field, such as arc 320, compared to some systems in which the transmitting fiber moves through a convex image field. At large angles, the fiber tip may deviate from arc 320 and such deviations may be compensated for by modifying the optical design. One of ordinary skill in the art will recognize many variations, modifications, and alternatives.

[0053] In an embodiment, each of the optical fiber links 310 and 312, except for the first optical fiber link 114, carries an optical signal, in this example, such that the three cores each emit a light beam, all of which are pointed toward a focal point. Fabrication of the structure can begin with a preform of a structural precursor of the optical fiber link in the form of a cylinder comprising a first material, which is embedded in a larger cylinder of a second material that is more easily etched. To manufacture the structure, a two-step process can be used, in which a first hot drawing process is used to draw the preform in a tapered manner so that the outer or peripheral cores are tilted towards the central core. A subsequent laser ablation / selective etching process can then be used to remove the second material from the pillar areas. Alternatively, Figure 3 The illustrated embodiments may be assembled from discrete components.

[0054] Fiber optic links 114, 310, and 312 may include optical fibers. They may be manufactured using methods known to those skilled in the art, such as thermal stretching. In an embodiment, retaining gasket 130 and / or base 110 include silicon wafers, silicon dioxide wafers, or metal wafers with through holes for fiber optic links. The fiber optic link may be coupled to the retaining gasket or base using adhesives, water glass, fritted glass, or metal bonding. Fritted glass may be applied to the connection as a preform (e.g., annular and surrounding the optical fiber) to facilitate consistent manufacturing. Metals (such as gold) may be deposited on the optical fiber, retaining gasket, and / or base using, for example, an evaporation process. A deformable micro-bump structure may be applied to one of the surfaces to facilitate metal-to-metal bonding under mechanical pressure. Alternatively, heating may be used to form a metal-to-metal bond. In an embodiment, the optical fiber is inserted and bonded to the retaining gasket, and then ground and polished as a unit to ensure coplanar termination of the optical waveguide.

[0055] From an optical point of view, Figure 3The illustrated embodiments provide benefits not obtainable using conventional techniques. Figure 4 is a simplified diagram showing elements of a fiber scanning system according to an embodiment of the present invention. Figure 4 As shown, the projection system includes an electromagnetic radiation source 421 (e.g., a diode laser) optically coupled to a first fiber optic link 415, and a ball lens 410 into which light from the first fiber optic link is directed. The ball lens 410 may be positioned approximately Figure 3 The optical system is arranged at the intersection point or focal point R shown, and a large field of view can be covered when a compact optical system is used. The ball lens can image the light from the optical fiber into the eyepiece of the display system. In addition to the ball lens, other entrance pupils of the optical system can also be used as focal points. As the first fiber link and the retaining washer sweep across the arc 405, the light emitted by the first fiber link is directed to the ball lens or entrance pupil from all oscillation positions 420, 422 and 424. The tilting of the fiber tip toward the ball lens 410 allows the use of optical elements that are less costly than other optical elements required to tilt the fiber tip away from the center as it moves toward the end of the range of motion.

[0056] The structure of the multi-element fiber scanner is suitable for use with the laser ablation and laser engraving techniques described in U.S. Provisional Patent Application Serial No. 62 / 438,408, filed on December 22, 2016, entitled "Methods and Systems for Fabrication of Shaped Fiber Elements Using Laser Ablation," the disclosure of which is incorporated herein by reference. As an example, starting with a multi-core optical fiber preform, the preform can be drawn to form an optical fiber, and laser ablation and etching can be used to remove material from the support portion, leaving the desired optical fiber link. The base and / or retaining plate can be formed from the glass in the original drawn optical fiber.

[0057] Fig.11 1 is a simplified side view of an optical fiber cable and a laser ablation beam according to an embodiment of the present invention. A laser beam is provided and propagates toward a lens 1110, which focuses the laser beam to a focal point 1120 inside a cladding 1115 of an optical fiber 1125. The focusing of the laser beam at the focal point results in the creation of a damage site at the focal point. By rotating the optical fiber along the longitudinal axis of the optical fiber aligned with the core, a series of damage sites can be created at a given radial distance.

[0058] Fig.11Movement of the laser beam and associated optical elements is shown as the laser beam moves longitudinally to a second position so as to form a second focal spot 1130 at a greater distance from the fiber surface. As the fiber rotates about the longitudinal axis, a series of damage sites are created that have a smaller radial distance from the fiber core than the series of damage sites associated with the focal spot 1120. Fig.11 Also shown is a third longitudinal position forming a third focus 1140. Using this process, a substantially continuous series 1150 of damage sites are created, shown in this embodiment by the tapering dashed outline.

[0059] In some embodiments, the lens is moved to adjust the position of the focused spot, while in other embodiments, the power of the lens can be adjusted so that the focal spot moves while the lens remains in substantially the same position. The term is used essentially because of the power change that is usually caused by moving an element inside a lens (e.g., a camera zoom lens).

[0060] As described below, an etching process can be used to preferentially etch along a series of damage sites. Fig.11 In the illustrated embodiment, a tapered fiber profile is formed and portions of the fiber cladding are separated at radial distances greater than a series of damage sites.

[0061] In some embodiments, as light propagates into the optical fiber toward the core, the optical fiber acts as a cylindrical lens in a direction extending into the figure. In the plane of the figure, the optical fiber does not introduce any focusing effect. The cylindrical lens introduced by the optical fiber may adversely affect the size of the focal point of the series 1150 that creates the damage site. Therefore, an astigmatic lens can be incorporated in the optical path along which the laser beam propagates. As an example, a cylindrical lens can be used as an astigmatic lens to introduce correction in a plane extending into the figure to compensate for the focusing caused by the optical fiber. In some embodiments, the astigmatic lens and / or lens 1110 have variable optical parameters so that the amount of astigmatism introduced and / or the focal length can be adjusted during system operation.

[0062] In some embodiments, separate lenses may be combined into a single lens, which may be a multi-element composite lens that both focuses the laser light into the fiber and provides astigmatism pre-correction to compensate for the cylindrical focusing that occurs in the fiber.

[0063] Fig.12 is a simplified flow chart illustrating a method of manufacturing a multi-element fiber optic scanner according to an embodiment of the present invention. Fig.12The described method is applicable to manufacturing various structures described herein, including a multi-element fiber scanner having a base, a retaining washer, a first fiber link including a fiber core and a fiber cladding, and a plurality of additional links coupling the base to the retaining washer. The method 1200 includes providing a fiber optic cable (1210), focusing a laser beam at a predetermined location inside the fiber optic cable (1212), and creating a damage site at the predetermined location (1214).

[0064] The method also includes focusing the laser beam at a series of additional predetermined locations inside the optical fiber cable (1216) and creating a plurality of additional damage sites at the additional predetermined locations (1218). In another embodiment, the damage sites and the additional damage sites define a multi-element structure including a waveguide element and a mechanical support element, such as Figure 1 , Figure 3 , Fig. 8A and Fig.10 As shown in . The mechanical support element may include a base and a retaining washer and a mechanical support coupled between the base and the retaining washer. In an embodiment, the damage site and the additional damage site define a tapered profile having a diameter that decreases as a function of the longitudinal distance toward the optical fiber emitting tip, thereby producing a tapered optical fiber.

[0065] The method further includes exposing the fiber optic cable to an etchant solution (1220), preferentially etching the damage site and a plurality of additional damage sites (1222), and separating a portion of the fiber optic cable to release components of a multi-component fiber scanner (1224). After the preferential etching process, the portion of the structure may include waveguide components, such as one or more optical fiber components having a core and an optical fiber cladding, and a mechanical structure.

[0066] According to embodiments of the present invention, as the laser beam propagates to the focal point / damage site and multiple additional damage sites, the focusing of the light by the optical fiber is compensated by using an astigmatic lens that introduces an amount of focusing equal and opposite to the focusing that occurred as the laser beam propagated through the optical fiber. Since the damage sites will be located at varying depths in the optical fiber cladding, i.e., varying distances from the core, in some embodiments, the corrective lens can be adjusted as the laser light traverses different radial distances in the optical fiber cladding.

[0067] In some embodiments, creating a plurality of additional damage sites at additional predetermined locations may include forming a grid of damage sites in the cladding of the optical fiber cable. For example, in some embodiments, a plurality of radial through holes may pass through the cladding region toward the core. The focus of the laser beam may be controlled so that a first portion of the plurality of additional damage sites is first created near the core (i.e., at a small radial distance from the core) and a second portion of the plurality of additional damage sites is subsequently created at a greater distance from the core (i.e., at a greater radial distance up to the diameter of the cladding region). The technique provides a damage-free material through which the laser beam propagates, reducing or preventing beam quality degradation.

[0068] The core is characterized by a longitudinal axis, and the method may include rotating the optical fiber about the longitudinal axis while creating a plurality of additional damage sites at additional predetermined locations. Fig.11 The optical fiber cable is shown as a substantially uniform material, but the optical fiber cable may include a cladding region and a plurality of sacrificial regions disposed in the cladding region. The plurality of sacrificial regions may include a material having a higher etching rate than the cladding region, or may be an air cavity through which an etchant may flow.

[0069] It should be understood that Fig.12 The specific steps shown provide a specific method for manufacturing a multi-element fiber scanner according to an embodiment of the present invention. According to alternative embodiments, other sequences of steps may also be performed. For example, alternative embodiments of the present invention may perform the steps outlined above in a different order. In addition, Fig.12 The various steps shown may include multiple sub-steps, which may be performed in various orders suitable for the various steps. In addition, additional steps may be added or removed depending on the specific application. One of ordinary skill in the art will recognize many variations, modifications, and substitutions.

[0070] Figure 5 is a simplified flow chart illustrating a method of manufacturing a multi-element fiber scanner according to an embodiment of the present invention. The method 500 of manufacturing a multi-element fiber scanner includes providing an optical fiber cable (510) having a cladding region and a core, focusing a laser beam at a series of predetermined locations inside the cladding region of the optical fiber cable (512), and creating a plurality of damage sites (514) at the predetermined locations. Creating the plurality of damage sites at the predetermined locations may include forming a grid of damage sites, a plurality of radial through holes through the cladding region toward the core, and the like. In one embodiment, the process of creating the plurality of damage sites at the predetermined locations may be by first creating a first portion of the plurality of damage sites near the core, and then creating a second portion of the plurality of damage sites near the periphery of the cladding region.

[0071] The method also includes exposing the optical fiber cable to an etchant solution (516) and preferentially etching a plurality of damage sites (518) to form a base having a base plane and a longitudinal axis orthogonal to the base plane, a retaining washer disposed a predetermined distance from the base along the longitudinal axis, including a fiber core, a first optical fiber link passing through the base plane and connected to the retaining washer, and a plurality of additional optical fiber links connected to the base, extending from the base to the retaining washer and connected to the retaining washer.

[0072] According to an embodiment of the present invention, the method may also include rotating the optical fiber cable around the longitudinal axis during the process of creating multiple damage sites at predetermined positions. In some embodiments, the optical fiber cable can be manufactured so that it includes multiple sacrificial regions arranged in the cladding region, and the sacrificial region is made of a material having a higher etching rate than the cladding region, so that the sacrificial material can be preferentially removed. Alternatively, the sacrificial region may include an air cavity or a combination of a sacrificial material and an air cavity.

[0073] Figure 6 6 is a simplified flow chart showing a method of manufacturing a multi-element fiber scanner according to another embodiment of the present invention. The method 600 of manufacturing a multi-element fiber scanner includes manufacturing a preform (610) including at least one fiber waveguide, a fiber support, and a sacrificial material, and drawing the preform to form a fiber structure (612).

[0074] In the optical fiber drawing process, the optical fiber preform may include a sacrificial region that may include a material having a lower etch resistance than the material used to define the first optical fiber link and the plurality of additional links or other mechanical supports. As an example, the first optical fiber link and the plurality of additional links may be resistant to etching, for example, by sulfuric acid or other suitable etchants, while the sacrificial region may be etched by sulfuric acid, and the sacrificial region may be doped or otherwise provided to reduce its etch resistance (which has an etching rate that depends on the concentration and type of the dopant and the etchant). In various embodiments, the dopant may include one or more of fluorine, fluoride, germanium, boron, phosphorus, gallium, indium, arsenic, and antimony. In some embodiments, the etching rate of the optical fiber link and / or the plurality of additional links may depend on the purity of the glass (e.g., sodium / boron / phosphate content) and whether the glass has been annealed.

[0075] The method also includes exposing the fiber optic structure to an etchant solution (614) and preferentially etching the sacrificial material (616) to form a base having a base plane and a longitudinal axis orthogonal to the base plane, a retaining washer disposed a predetermined distance from the base along the longitudinal axis, including at least one fiber optic waveguide, a first fiber optic link extending through the base plane and connected to the retaining washer and connected to the base, and a plurality of fiber optic supports extending from the base to the retaining washer and connected to the retaining washer.

[0076] During the preferential sacrificial etching process, the base and retaining washer can be masked during the etching process to protect them. In addition to their optical properties, the mechanical properties of the materials can also be selected. Therefore, in some embodiments, the base and retaining washer can be excluded from the laser damage process in order to reduce their sensitivity to etching.

[0077] Figure 7 700 is a simplified flow chart illustrating a method of operating a multi-element fiber scanner according to an embodiment of the present invention. As described below, as the actuator base translates laterally in a base plane, the retaining washer translates laterally in a plane group as it oscillates. For small angles, the fiber tip oscillates in a substantially single plane, which provides a flat image field. In some embodiments, the fiber tip oscillates in a plane group while maintaining the fiber tip in a longitudinal orientation. The method 700 of operating a multi-element fiber scanner includes providing an electromagnetic radiation source (710) and directing electromagnetic radiation from the source through a first fiber link (712). The first fiber link passes through a base having a base plane and a longitudinal axis orthogonal to the base plane.

[0078] The method also includes supporting a retaining washer (714) disposed a predetermined distance from the base along the longitudinal axis. In some embodiments, a plurality of additional links connect the base to the retaining washer. One or more of the plurality of additional links may pass through the base. In this case, the method may include directing electromagnetic radiation from the source (or from another source) through one or more of the plurality of additional links. The electromagnetic radiation may be modulated in intensity to present an image.

[0079] The method further includes translating the base (716) in a base plane, translating a retaining washer (718) in a set of planes parallel to the base plane, and scanning the electromagnetic radiation (720) on one or more axes. In view of the movement of the retaining washer, the present invention includes small angles of movement that are substantially within the plane of the retaining washer. Thus, for these examples, as the retaining washer oscillates laterally, it may move a small amount out of the initial plane in the longitudinal direction at the end of the range of motion. As an example, in some embodiments, the vertical deviation from the initial position of the retaining washer may be in the range of microns to millimeters, for example, 500 μm or greater. As the oscillation angle and range of motion increase, the movement of the retaining washer is limited by the set of planes parallel to the base plane and includes vertical changes as the retaining washer moves laterally and longitudinally. As described herein, because the retaining washer moves in a plane parallel to the base plane, the optical fiber tip is oriented in the longitudinal direction during movement, providing benefits related to the design of optical imaging systems.

[0080] In an embodiment, translating the base in the base plane is performed by actuating the base in a first direction and actuating the base in a second direction orthogonal to the first direction to provide two-dimensional motion.Translating the retaining washer in a set of planes parallel to the base plane may include tilting the plurality of additional links.

[0081] Fig. 8A 800 is a simplified perspective view showing a multi-axis fiber scanner according to an embodiment of the present invention. The multi-element fiber scanner can be used to scan electromagnetic imaging radiation. The multi-element fiber scanner 800 includes a base 110 having a base plane and a longitudinal axis orthogonal to the base plane. The multi-element fiber scanner also includes a first fiber link 114 that passes through the base in a direction parallel to the longitudinal axis. The first fiber link is operably coupled to at least one electromagnetic radiation source (not shown) at a position below the base 110.

[0082] In addition, the multi-element fiber scanner includes a plurality of actuating elements 810 connected to the base 110 and extending from the base along the longitudinal axis (e.g., parallel to the longitudinal axis). The plurality of actuating elements can be independently expanded 812 and retracted 814. Fig. 8A The relative actuating elements 810 shown enable independent scanning of the first fiber link in two directions (e.g., along an x-axis and a y-axis both orthogonal to the longitudinal axis) such that light from the first fiber link can be directed to pixels defining an array parallel to the x-axis and the y-axis and perpendicular to the longitudinal axis (i.e., the z-axis).

[0083] Multiple actuator elements can be fabricated using multiple piezoelectric tube stacks and can be arranged around the first optical fiber link. Additional description of the piezoelectric tube stack is relative to Figure 9A-9F In addition to the mechanical constraint of the base on the retaining washer, the actuating element 810 can be used to control the distance between the base and the retaining washer 130, which is set at a predetermined distance from the base along the longitudinal axis. The first optical fiber link and the plurality of actuating elements are connected to the retaining washer. The first optical fiber link passes through the retaining washer in a direction parallel to the longitudinal axis.

[0084] refer to Fig. 8A, the actuating element may include a first piezoelectric element positioned on a first side of the first optical fiber link and operable to contract / expand, and a second piezoelectric element positioned on a second side of the first optical fiber link opposite to the first side and operable to expand / contract relative to the first piezoelectric element. These movements will cause the retaining washer to tilt around a first axis orthogonal to a line connecting the first piezoelectric element and the second piezoelectric element. In addition, a third piezoelectric element may be positioned on a third side of the first optical fiber link and operable to contract / expand. The third piezoelectric element is paired with a fourth piezoelectric element, which is positioned on a fourth side of the first optical fiber link opposite to the third side and operable to expand / contract relative to the third piezoelectric element. The movement of the third and fourth piezoelectric elements will cause the retaining washer to tilt around a second axis orthogonal to a line connecting the third piezoelectric element and the fourth piezoelectric element.

[0085] Using the actuating elements as described above to operate a multi-element fiber scanner, the first fiber link can be scanned to move the electromagnetic radiation spot along an axis parallel to the base plane. In this embodiment, the scanning function is built into the mechanical support, for example, where a piezoelectric actuator is used as a servo element (e.g., a piston).

[0086] Despite Fig. 8A In the illustrated embodiment the actuator element is shown as cylindrical, but the invention does not require this particular shape and other cross-sections are also within the scope of the invention including rectangular, square, hexagonal, etc. The cross-section of the actuator element may be uniform or non-uniform along the length of the actuator element.

[0087] Figure 8B 850 is a simplified flow chart illustrating a method of operating a multi-axis fiber optic scanner according to an embodiment of the present invention. The method 850 of operating a multi-element fiber optic scanner includes providing an electromagnetic radiation source (860) and directing electromagnetic radiation from the source through a first fiber optic link (862). The first fiber optic link passes through a base having a base plane and along a longitudinal axis orthogonal to the base plane. The method also includes supporting a retaining washer (864) disposed a predetermined distance from the base along the longitudinal axis. A plurality of piezoelectric actuators connect the base to the retaining washer. As shown in FIG. Fig. 8AAs shown, a first piezoelectric actuator of a plurality of piezoelectric actuators connects one side of the base to one side of the retaining washer, and a second piezoelectric actuator of a plurality of piezoelectric actuators connects the opposite side of the base to the opposite side of the retaining washer. The first piezoelectric actuator and the second piezoelectric actuator are located in a scanning plane. In some embodiments, the scanning plane may include a central waveguide / optical fiber, but with the aid of two other actuators, the tip of the optical fiber may not be limited to a plane including the static positions of the two opposing piezoelectric actuators and the central waveguide / optical fiber. Therefore, one mode of operation is to drive the first pair of opposing actuators and the remaining (e.g., two) opposing actuators at the resonant frequency of the optical fiber at a lower frequency that can be associated with the vertical scanning frequency. In another mode of operation, a spiral scanning mode is utilized.

[0088] The method further includes actuating a first piezoelectric actuator of the plurality of piezoelectric actuators to decrease a distance from one side of the base to one side of the retaining washer (866), and actuating a second piezoelectric actuator of the plurality of piezoelectric actuators to increase a distance from an opposite side of the base to an opposite side of the retaining washer (868). In response to the actuations, the method enables scanning of the first optical fiber link in a scanning plane (870).

[0089] Fig. 9A 2 is a simplified side view showing a multi-section motion actuator according to an embodiment of the present invention. Fig. 9A As shown, the multi-section element 905 includes a first piezoelectric element 910 coupled to a second piezoelectric element 912. The multi-section element 905 can be referred to as a piezoelectric tube stack because several piezoelectric elements are stacked to form the element. In some embodiments, the first piezoelectric element 910 is close to the base and the second piezoelectric element 912 is located at a position away from the base. Each piezoelectric element is capable of contracting or expanding, and as Fig. 9A As shown, the piezoelectric elements can be operated so that the lower portion contracts / expands while the upper portion expands / contracts. In some embodiments, each piezoelectric element includes multiple sectors (e.g., 4 sectors) so that one side of each tube can be contracted while the other side is expanded. This mode of operation will produce Fig. 9B The oscillating motion shown.

[0090] Fig. 9B is a diagram showing an embodiment of the present invention Fig. 9A Simplified side view of the oscillatory motion of a multi-segment motion actuator shown. As the first piezoelectric element 910 contracts (920), the second piezoelectric element 912 expands (922), causing the multi-segment motion actuator to assume an S-shape. In the next phase of oscillation, as the first piezoelectric element 910 expands (924), the second piezoelectric element 912 contracts (926), causing the multi-segment motion actuator to assume a second S-shape that mirrors the first S-shape. By alternately expanding / contracting the piezoelectric elements that make up the segment, the multi-segment motion actuator will be as follows Fig. 9B The shown oscillates, forming the shown shape and horizontal mirror image in an alternating manner.

[0091] Fig. 9C is a diagram showing a method of performing the above-mentioned steps according to an embodiment of the present invention. Fig. 9A A simplified side view of a multi-element fiber scanner showing a multi-element motion actuator element. Fig. 9C As shown, the use of a multi-jointed motion element 905 that couples the base 110 to the retaining washer 130 reduces the amount of bending at the locations where the bottom and top of the actuating element connect to the base and retaining washer, respectively. Due to the reduced bending at these points, stress is reduced and life and reliability can be improved. Fig. 9C As shown, the vertical distance (measured in the longitudinal direction) between the retaining washer 130 and the base 110 decreases in the lateral direction as the retaining washer moves horizontally away from the center position. For small oscillations of the retaining washer 130, the movement of the retaining washer will be substantially planar. When the retaining washer moves laterally away from the center, although the longitudinal height can be reduced, the movement is in a plane parallel to the base plane, and the orientation of the retaining washer remains substantially parallel to the base. Because the retaining washer remains parallel to the base plane when it moves, the tip of the optical fiber 940 remains oriented in the longitudinal direction. When designing an optical system to generate an optical fiber image when the optical fiber is scanned, the field curvature associated with the lateral (and longitudinal) movement of the retaining washer can be considered. Fiber scanners with a fiber tip tilted away from the center when the fiber tip moves laterally toward the end point of the range of motion require a larger numerical aperture optical system to effectively collect and image light from the optical fiber. Larger numerical aperture requirements usually lead to larger, more complex and more expensive optical systems. The size of the optical system is an important consideration for the optical system to be integrated into the augmented reality glasses. In contrast, embodiments of the present invention maintain the fiber tip in a longitudinal orientation because the washer is held parallel to the base plane throughout the range of motion. When the tip is tilted at the ends of the range of motion, light can be emitted at steep angles, which can result in a more complex and expensive lens design due to the need to correct for high levels of field curvature and steep angles. Using embodiments of the present invention, maintaining the fiber tip orientation as the fiber is scanned significantly simplifies the complexity and cost of the lens. Those of ordinary skill in the art will recognize many variations, modifications, and alternatives.

[0092] Fig.9D is a simplified perspective view of a piezoelectric motion actuator according to an embodiment of the present invention. Fig.9D The illustrated piezoelectric motion actuator 955 includes four actuation inputs (+X, -X, +Y, and -Y) disposed in a cylindrical housing. A fiber optic cable passes through an aperture 957 and through actuation of the four actuation inputs, the fiber optic cable can be scanned in two dimensions. Fig.9DIn the example, the contraction of the +X actuation input and the expansion of the -X actuation input cause the piezoelectric motion actuator to tilt toward the +X axis. Fig.9D The motion shown is in two dimensions (i.e., along a plane defined by the x-axis and the y-axis), but embodiments can also simultaneously expand or contract all four actuation inputs to contract / expand along the z-axis. Thus, embodiments of the present invention provide motion in the x-direction and the y-direction, as well as using a cylindrical actuator that compresses / expands in the z-direction.

[0093] Apart from Fig.9D In addition to the cylindrical motion actuator shown, the scope of the present invention includes other geometric shapes for the motion actuator. As an example, in an embodiment, the motion actuator includes multiple opposing motion actuator elements (e.g., piezoelectric elements) that operate in conjunction with each other as a multi-element motion actuator. Fig.9E is a simplified end view showing a multi-element motion actuator in accordance with an embodiment of the present invention. Fig.9E The view shown is aligned with the longitudinal axis. Fig.9E As shown, a first motion actuator 962 positioned on one side of a fiber optic cable 960 and a second motion actuator 964 positioned on the opposite side of the fiber optic cable can be contracted / expanded in coordination to move the fiber optic cable in a horizontal plane. A third motion actuator 966 positioned on the third side of the fiber optic cable 960 and a fourth motion actuator 968 positioned on the opposite side of the fiber optic cable can be contracted / expanded in coordination to move the fiber optic cable in a vertical plane. By actuating all four motion actuators, the optical fiber can be scanned in two dimensions to be suitable for projection displays. Fig.9E The illustrated embodiment can provide a lighter system by reducing the piezoelectric mass. Fig.9E In addition to the rectangular geometries shown, other geometries including hexagons, triangles, etc. are also within the scope of the present invention.

[0094] Typically, the actuation inputs are driven with a predetermined phase relationship between the inputs (e.g., 90° out of phase, 180° out of phase, etc.). As an example, to achieve Fig.9D The motion shown, contraction of the +X actuation input and extension of the -X actuation input, can be achieved by driving these actuation inputs with signals that are 180° out of phase with respect to each other. Fig. 9A and Fig. 9C , you can Fig.9D The first piezoelectric element 910 is driven as shown, causing the first element to bend in the +X direction. At the same time, the second piezoelectric element 912 can be driven in the opposite manner, that is, expanding the +X actuation input and contracting the -X actuation input, causing the second element to bend in the -X direction. As a result, the coordinated actuation of these piezoelectric elements can achieve Fig. 9BThus, the phase relationship between the actuation inputs to each element and the phase relationship between the individual elements are controlled to achieve the desired motion.

[0095] Fig.9F 2 is a simplified side view showing a multi-section motion actuation structure according to an embodiment of the present invention. Fig.9F As shown, the piezoelectric structure 979 includes a Fig. 9A The piezoelectric structure 979 can be referred to as a piezoelectric tube stack because in this embodiment two piezoelectric elements (also called piezoelectric motion actuators) are stacked to form the structure. The lower portion of the piezoelectric structure 979 is attached to a fixed base so that the top of the structure can move in response to an electrode drive voltage. Fig. 9A , Fig.9D and Fig.9F compared to, Fig.9D The single piezoelectric element shown will be stacked with a second piezoelectric element to form Fig. 9A and Fig.9F The tube stack shown. For clarity, the actuation input on the outer surface of the piezoelectric element is omitted (see Fig.9D ), and electrodes connected to the actuation input are shown. The interior of the piezoelectric element is metallized and connected to ground. As described herein, four phases are applied to the actuation inputs arranged at 90° orientation relative to each other around the outer surface of the piezoelectric element.

[0096] Although about Fig.9F Tube stacking is discussed, but embodiments of the present invention are not limited to multi-piezoelectric element implementations. In some embodiments, an integral multi-section piezoelectric element having a lower portion and an upper portion can be utilized that is made of an integral piezoelectric tube. According to an alternative embodiment, an optical fiber with modulated light can pass through the piezoelectric structure 979. Thus, these piezoelectric structures can be used not only for mechanical functions, but also for light transmission.

[0097] Signal generator 970 provides an output that is connected to electrodes 973 and 975, which in turn are connected to corresponding actuation inputs (e.g., Fig.9D The signal generator 970 is also connected to a first 90° phase shifter 971 and a second 90° phase shifter 972, which are connected to electrodes 974 and 976, which are in turn connected to corresponding actuation inputs (e.g., Fig.9D Thus, the signal generator and the phase shifter cooperate to provide four phases that are 90° out of phase with respect to each other.

[0098] At the intersection 980 of the first and second piezoelectric elements, the electrodes form a spiral structure that moves the position of the electrodes by 180°. The spiral structure enables the piezoelectric drive electrodes to be interchanged 180° at the intersection 980, which corresponds to the inflection point of the S curve. Therefore, for example, the electrode 974 that contacts the actuation input in area 977 (i.e., the left side of the first piezoelectric element) is offset to contact the actuation input in area 978 (i.e., the right side of the second piezoelectric element). For other electrodes, a similar 180° offset occurs in the electrode position, resulting in the electrode contacting the right / left or front / rear side of the first piezoelectric element also contacting the left / right or rear / front side of the second piezoelectric element. As an example, the phase shift between the electrodes of the first piezoelectric element can be defined as 0° (i.e., front actuation input) of electrode 973, 90° (left actuation input) of electrode 974, 180° (i.e., rear actuation input) of electrode 975, and 270° (i.e., right actuation input) of electrode 976.

[0099] In operation, a field is applied radially from an actuation input on the outer surface of the piezoelectric element to a common ground electrode on the inner surface of the piezoelectric element. Because the left / right and front / back actuation inputs are driven by electrodes that are 180° out of phase, the left / front side of the piezoelectric element is contracted and the right / back side of the piezoelectric element is expanded. Fig.9F In the illustrated embodiment, the presence of the helical structure at intersection 980 causes the opposing actuation inputs on the two piezoelectric elements to respond in the same manner. For example, since the +X actuation input on the first piezoelectric element and the -X actuation input on the second piezoelectric element are connected to the same electrode (e.g., electrode 974), they will contract / expand at the same time. Thus, in response to the voltage present on electrode 974, where region 977 contracts and region 978 contracts, as shown in FIG. Fig. 9B The S-curve operation shown is Fig.9F The electrode drive configuration shown produces. Since the electrodes on opposite sides of the piezoelectric element are 180° out of phase, expansion of the region opposite regions 977 and 978 will facilitate S-curve operation.

[0100] When the voltage applied to the four actuation inputs of each actuation input varies according to time, the free end 981 of the second piezoelectric element may sweep out a circle in a plane perpendicular to the longitudinal direction (ie, the z direction).

[0101] Reference again Fig. 8A and Figures 9A-9F In some embodiments, one or more fiber optic links may be replaced with motion-actuated links, e.g., in combination with Fig. 9AThe multi-section motion actuator element shown. Therefore, an embodiment of the present invention provides a multi-element fiber optic scanner for scanning electromagnetic imaging radiation. The multi-element fiber optic scanner includes: a base having a base plane and a longitudinal axis orthogonal to the base plane; and a first fiber optic link passing through the base in a direction parallel to the longitudinal axis. The first fiber optic link is operably coupled to at least one electromagnetic radiation source.

[0102] The multi-element fiber scanner also includes a plurality of motion actuation links connected to and extending from the base. Each of the plurality of motion actuation links includes a first piezoelectric element proximate to the base and a second piezoelectric element coupled to the first piezoelectric element at a position away from the base. The multi-element fiber scanner further includes a retaining washer disposed a predetermined distance from the base along the longitudinal axis. The first fiber link and the second piezoelectric element of each of the plurality of motion actuation links are connected to the retaining washer.

[0103] Fig.10 The invention is a multi-element fiber scanner for scanning electromagnetic imaging radiation according to an embodiment of the present invention. The multi-element fiber scanner 1000 can be used in a display for scanning electromagnetic imaging radiation and includes a base 1005 having a support surface 1011 (the lower surface of the base 1005) defining a base plane, a mounting surface 1007 opposite the support surface 1011, and a longitudinal axis orthogonal to the base plane. The multi-element fiber scanner also includes a plurality of motion actuators 1009 coupled to the support surface 1011 of the base 1005.

[0104] The multi-link fiber optic structure is coupled to the mounting surface 1007. The multi-link fiber optic structure includes: a fiber optic base 1010, which can be similar to the base 110; and a fiber optic link 1014 that passes through the fiber optic base 1010 in a direction parallel to the longitudinal axis. The fiber optic link 1014 is operably coupled from at least one electromagnetic radiation source (not shown) to the distal end ( Fig.10 perspective view of the top).

[0105] The multi-link optical fiber structure further includes: a plurality of motion actuator elements 1040 (e.g., piezoelectric actuator elements) connected to the optical fiber base 1010 and extending from the optical fiber base 1010 along the longitudinal axis; and a retaining washer 1030 disposed at a predetermined distance from the optical fiber base along the longitudinal axis. The optical fiber links 1014 and the plurality of motion actuator elements 1040 are connected to the retaining washer 1030.

[0106] In an embodiment, one or more of the plurality of motion actuation elements 1040 are replaced with additional links coupled to an electromagnetic radiation source. In addition, multiple additional links coupled to the same or different electromagnetic radiation sources may be utilized to simultaneously output multiple pixels for a multi-pixel display.

[0107] Actuation of the base 1005 using multiple motion actuators 1009 acting as pistons results in tilting of the base about the axis of the base 1005. The tilting may be about a single axis or about multiple axes. In some embodiments, in order to tilt the base and actuate the motion actuator elements to keep the washer tilted, a motion of the fiber optic link is provided, such as oscillation, to direct light emitted from the fiber optic link toward the display screen.

[0108] In some configurations, translation and / or tilting of the retaining washer can provide scanning of the fiber link in a first direction, and tilting of the base can provide scanning of the fiber link in a second direction, which can be orthogonal to the first direction. In an embodiment, the first direction is a fast direction (similar to the horizontal scan of a raster scan display), and the second direction is a slow direction (similar to the vertical scan rate of a raster scan display). As an example, the retaining washer can oscillate in a transverse direction, and the base can tilt in a transverse direction. In addition to the tilting of the base, the base can translate in a longitudinal direction by simultaneously extending / contracting all motion actuators.

[0109] It should also be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes thereto may be suggested by those skilled in the art and are to be included within the spirit and purview of the present application and the scope of the appended claims.

Claims

1. A multi-element fiber optic scanner for scanning electromagnetic imaging radiation, the multi-element fiber optic scanner comprising: a base having a base plane and a longitudinal axis orthogonal to the base plane; an optical fiber link extending through the base in a direction parallel to the longitudinal axis, wherein the optical fiber link is operably coupled to at least one electromagnetic radiation source; a retaining washer disposed along the longitudinal axis at a predetermined distance from the base; The first group of piezoelectric tubes, including: A first piezoelectric tube of the first set of piezoelectric tubes is joined to and extends from the base; and A second piezoelectric tube of the first set of piezoelectric tubes is joined to and extends from the retaining washer; and The second group of piezoelectric tubes, including: A first piezoelectric tube of the second set of piezoelectric tubes is joined to and extends from the base; and a second piezoelectric tube of the second set of piezoelectric tubes is joined to and extends from the retaining washer, Wherein, the optical fiber link passes through the retaining washer in a direction parallel to the longitudinal axis.

2. The multi-element optical fiber scanner according to claim 1, wherein: The first piezoelectric tubes in the first group of piezoelectric tubes and the first piezoelectric tubes in the second group of piezoelectric tubes are aligned with a direction parallel to the longitudinal axis.

3. The multi-element optical fiber scanner according to claim 1, wherein: The first piezoelectric tube in the first group of piezoelectric tubes and the first piezoelectric tube in the second group of piezoelectric tubes are tilted toward the optical fiber link.

4. The multi-element optical fiber scanner according to claim 1, wherein: The at least one electromagnetic radiation source comprises an intensity modulated source.

5. The multi-element optical fiber scanner according to claim 1, wherein: The first set of piezoelectric tubes is located on a first side of the optical fiber link, and the second set of piezoelectric tubes is located on a second side of the optical fiber link opposite the first side.

6. The multi-element fiber optic scanner of claim 5, wherein: The first piezoelectric tube in the first group of piezoelectric tubes and the first piezoelectric tube in the second group of piezoelectric tubes are operable to bend toward a first direction; and At the same time, the second piezoelectric tube in the first group of piezoelectric tubes and the second piezoelectric tube in the second group of piezoelectric tubes are operable to bend toward a second direction opposite to the first direction.

7. The multi-element optical fiber scanner according to claim 6, wherein: The optical fiber link is operable to bend relative to the base toward the first direction while the first piezoelectric tube in the first group of piezoelectric tubes and the first piezoelectric tube in the second group of piezoelectric tubes are bent toward the first direction.

8. The multi-element fiber scanner according to claim 1, wherein: The retaining washer is operable to translate in a set of planes parallel to the base plane.

9. The multi-element fiber scanner of claim 1, wherein: The retaining washer is operable to translate along a curved arc.

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