Patent Description:
Imaging systems can be used to present visual information to a user. For example, an imaging system can include an optical component that projects images onto an imaging surface, such that one or more users can view the image. In some cases, imaging systems can be incorporated into a head-mounted display device to present visual information in a more immersive manner. For example, head-mounted displays can be used to present visual information for virtual reality (VR) or augmented reality (AR) systems.

<CIT> discloses an optical coupler for coupling to a rotating catheter has a housing with a rotatable distal face and a stationary proximal face. The distal face has an eccentric port and a central port. A lens is disposed inside the housing to intercept a rotating collection beam emerging from the eccentric port and to re-direct the collection beam to a focus proximal to the lens as the collection beam rotates. A beam re-director disposed between the lens and the distal face is oriented to direct a delivery beam toward the central port.

The invention is directed to an apparatus according to claim <NUM>. Further developments are according to dependent claims <NUM>-<NUM>.

The invention is also directed to an apparatus according to claim <NUM>. A further development of the invention is according to claim <NUM>.

The invention is also directed to an apparatus according to claim <NUM>.

In general, a fiber scanned display (FSD) device projects images onto an imaging surface by directing a time-modulated light pattern through an optical fiber while vibrating the optical fiber tip. For instance, a FSD device can vibrate an optical fiber using an actuator, such that the tip of the optical fiber travels along or "scans" a predictable predefined pattern or path (e.g., a spiral). As the tip of the optical fiber scans the pattern, modulated light is transmitted through the optical fiber, such that light is emitted from the tip of the optical fiber in a spatially-dependent manner. Accordingly, images can be spatially "scanned" onto an imaging surface by continuously vibrating the optical fiber while transmitting a sequence of light pulses into the optical fiber.

An example FSD device <NUM> is shown schematically in <FIG>. The FSD device <NUM> includes several radiation sources 102a-c configured to emit light (e.g., a red laser, a green laser, and a blue laser, respectively). The radiation sources 102a-c are optically coupled to a first waveguide <NUM> (e.g., a red-green-blue (RGB) combiner), such that light emitted by each of the radiation sources is combined. The combined light from the first waveguide <NUM> is relayed by a second waveguide <NUM> (e.g., a single mode optical fiber) optically coupled to the first waveguide <NUM>. In turn, the light from the second waveguide <NUM> is emitted from its tip <NUM> (e.g., a cantilevered fiber tip).

The emitted light passes through a lens assembly <NUM> that focuses the emitted light onto an image plane <NUM>. As the light is being emitted, the waveguide tip <NUM> is scanned along one or more axes by an actuator <NUM> (e.g., a piezoelectric tube actuator), such that the emitted light is projected according to a scan pattern along the image plane <NUM> (e.g., a spiral). As a result, a scanned image (e.g., a spiral-scanned image) is formed on the image plane <NUM>.

As shown in <FIG>, the waveguide tip <NUM> can be scanned by imparting a force onto the waveguide <NUM> using the actuator <NUM>. The waveguide <NUM> is flexible, causing the waveguide tip <NUM> to defect by an angle α relative to the longitudinal axis <NUM> of the actuator <NUM>. Operation of the actuator <NUM> can be selectively regulated to deflect the waveguide tip <NUM> along one or more axes orthogonal to axis <NUM>, such that the waveguide tip <NUM> scans a particular predefined pattern.

The intensity of light emitted by the radiation sources 102a-c is modulated so that the light is coupled into the waveguide <NUM> as a sequence of pulses. The FSD device <NUM> coordinates the pulse sequence with the actuation of the waveguide tip <NUM> such that light is selectively emitted from the waveguide tip <NUM> in a spatially-dependent manner so as to form an image. For example, as the actuator <NUM> is continuously scanning the waveguide tip <NUM> according to a predictable predefined pattern, the radiation sources 102a-c each can selectively emit light and/or regulate the intensity of light emission according to that pattern and in sufficiently short time intervals, such that the sequentially formed light pattern on the image plane <NUM> appears as an image to the user. This can be useful, for example, to depict objects, shapes, and/or patterns on the image plane <NUM>. Further still, the radiation sources can also emit light in according to a dynamic pattern, such as a sequence of different images are projected onto the image source over time (e.g., to impart a sense of motion, such as in a video sequence, on the image plane <NUM>).

As shown in <FIG>, the FSD device <NUM> includes a drive module <NUM> that coordinates the operation of the actuator <NUM> and the operation of the radiation sources 102a-c. For instance, the drive module <NUM> can generate a drive signal to the actuator <NUM> to control the actuation of the actuator <NUM> (e.g., such that the actuator <NUM> causes the waveguide tip <NUM> to scan a predictable predefined pattern). The drive module <NUM> can also generate a pixel modulation signal to regulate the output of the radiation sources 102a-c in accordance with the actuation of the actuator <NUM>. The drive signal and the pixel modulation signal can be transmitted simultaneously to the actuator <NUM>, such that pixels are formed at specific spatial locations along the image plane <NUM>.

As an example, a drive signal can be modulated in accordance with the exemplary pattern shown in plot <NUM> of <FIG>, such that the signal constitutes a sinusoidal drive signal that is amplitude modulated over time. The drive signal can include a sinusoidal signal portion that drives one scan axis of actuator <NUM>, as well as a second sinusoidal signal portion that drives a second scan axis. The second sinusoidal drive signal is phase-shifted relative to the first drive signal portion, such that the waveguide tip <NUM> sweeps through a circular scan pattern. The sinusoidal drive signal can be amplitude modulated over time to dilate and contract this circular scan pattern to form an area-filling spiral scan pattern. A simplified scan pattern <NUM> is shown in <FIG>. Similarly, the pixel modulation signal can be generated in accordance with the scan pattern <NUM>, such that pixels are formed at specific spatial locations along the scan pattern <NUM>.

In some cases, multiple FSD devices can be used in conjunction (e.g., in a twodimensional array) to increase the quality of the projected image. As an example, multiple FSD devices can be implemented in an array to increase the resolution of projected images, increase the pixel density of projected images, and/or to increase the frame rate by which images are projected).

Implementations of the FSD device <NUM> can be used in a variety of imaging applications. For example, in some cases, FSD devices <NUM> implemented in a head mounted display device. One or more FSD devices <NUM> can be used to project images onto eyepieces positioned over a user's eyes, such that they are within the user's field of view. In some cases, FSD devices <NUM> can be implemented as a part of a "virtual reality" system or an "augmented reality" system to present images in a visually immersive manner.

As described with respect to <FIG>, an actuator <NUM> imparts a force onto the waveguide <NUM>, such that the waveguide tip <NUM> is scanned along one or more axes according to a predictable predefined pattern. This can be implemented by mechanically coupling the actuator <NUM> to the waveguide <NUM> using a mechanical joint <NUM>.

<FIG> and <FIG> show a perspective view (<FIG>) and a cross-sectional view (<FIG>) of an example actuator <NUM>, an example waveguide <NUM>, and an example mechanical joint <NUM>. For ease of illustration, portions of the actuator <NUM> have been omitted. <FIG> show the mechanical joint <NUM> according to a front perspective view (<FIG>), a rear perspective view (<FIG>), a cross-sectional view (<FIG>), and a top view (<FIG>).

The actuator <NUM> extends along a longitudinal axis <NUM>. The actuator <NUM> has a tube-like configuration, and includes an outer wall <NUM> encircling a hollow inner channel <NUM>. The actuator <NUM> has a circular or substantially circular cross-section. In some cases, the actuator <NUM> is a piezoelectric tube actuator.

The waveguide <NUM> is threaded through the inner channel <NUM> of the actuator <NUM>, and extends along the longitudinal axis <NUM>. The waveguide <NUM> is mechanically coupled to the actuator <NUM> via the mechanical joint <NUM>, such that a force induced by actuator <NUM> (e.g., due to vibrations generated by the actuator <NUM> along its outer wall <NUM>) is coupled to the waveguide <NUM>. The waveguide <NUM> can be an optical fiber (e.g., a single mode optical fiber).

The mechanical joint <NUM> includes a neck portion <NUM>, a collar portion <NUM>, and a flexural element portion <NUM>. In some cases, the mechanical joint <NUM> can be implemented as an integral component. In some cases, the mechanical joint <NUM> can be constructed from two or more discrete components.

The neck portion <NUM> is configured to attach to waveguide <NUM>, such that the mechanical joint and the waveguide <NUM> are mechanically coupled. In some cases, the neck portion <NUM> can be mechanically and/or chemically attached to the waveguide <NUM>. For example, the neck portion <NUM> can be attached to the waveguide <NUM> through metallization or diffusion. As another example, the neck portion <NUM> can be attached to the waveguide <NUM> through the use of urethanes, epoxies, or nanoparticles.

The neck portion <NUM> extends along the longitudinal axis <NUM>. The neck portion <NUM> has a tube-like configuration, and includes an outer wall <NUM> encircling a hollow inner channel <NUM>.

The inner channel <NUM> is dimensioned to receive the waveguide <NUM>. In some cases, the cross-sectional shape of the inner channel <NUM> can be identical or substantially identical as that of the waveguide <NUM>. For example, if the cross-sectional shape of the waveguide <NUM> is circular or substantially circular, the inner channel <NUM> also can be have a circular or substantially circular cross-section. In some cases, the diameter of the inner channel <NUM> can be substantially the same as the diameter of the waveguide <NUM>, such that the waveguide <NUM> securely contacts an inner surface <NUM> of the outer wall <NUM> facing the longitudinal axis <NUM> (e.g., through a friction fit).

In some cases, the neck portion <NUM> can include one or more slots along the outer wall <NUM>. For example, as shown in <FIG>, the neck portion <NUM> can include several slots <NUM> that extend through the outer wall <NUM>. Each slot <NUM> can each extend partially or entirely along the neck portion <NUM>. The slots <NUM> can be beneficial, for example, in facilitating flexure of the mechanical joint <NUM>. As shown in <FIG>, the slots <NUM> can be evenly azimuthally spaced about the longitudinal axis <NUM>. Although four slots <NUM> are shown in <FIG> and <FIG>, in practice, the neck portion <NUM> can include any number of slots (e.g., one, two, three, or more slots), or no slots at all.

The collar portion <NUM> is configured to mechanically couple to the actuator <NUM>. The collar portion <NUM> extends along the longitudinal axis <NUM>. The collar portion <NUM> has a tube-like configuration, and includes an outer wall <NUM> encircling a hollow inner channel <NUM>.

The inner channel <NUM> is dimensioned to receive the actuator <NUM>. In some cases, the cross-sectional shape of the inner channel <NUM> can be identical or substantially identical as that of the actuator <NUM>. For example, the if the cross-sectional shape of the actuator <NUM> is circular or substantially circular, the inner channel <NUM> also can be have a circular or substantially circular cross-section. In some cases, the diameter of the inner channel <NUM> can be substantially the same as the diameter of the actuator <NUM>, such that the actuator <NUM> securely contacts an inner surface <NUM> of the outer wall <NUM> facing the longitudinal axis <NUM> (e.g., through a friction fit). In some cases, the diameter of the inner channel <NUM> can be larger than the diameter of the actuator <NUM>, such that a gap region <NUM> is defined between the inner surface <NUM> of the outer wall <NUM> and the actuator <NUM>.

In some cases, the collar portion <NUM> can include one or more slots along the outer wall <NUM>. For example, as shown in <FIG> and <FIG>, the collar portion <NUM> can include several slots <NUM> that extend through the outer wall <NUM>. Each slot <NUM> can each extend partially or entirely along the collar portion <NUM>. The slots <NUM> can be beneficial, for example, in facilitating flexure of the mechanical joint <NUM>. Although four slots <NUM> are shown in <FIG> and <FIG>, in practice, the collar portion <NUM> can include any number of slots (e.g., one, two, three, or more slots), or no slots at all.

The flexural element portion <NUM> is configured to mechanically couple the neck portion <NUM> to the collar portion <NUM>, such that forces imparted onto the collar portion <NUM> (e.g., due to vibrations generated by the actuator <NUM>) are coupled to the neck portion <NUM>. In some cases, portions of flexural element portion <NUM> or an entirety of the flexural element portion <NUM> can bend with respect to the neck portion <NUM> and/or the collar portion <NUM>, such that the neck portion <NUM> and the collar portion <NUM> are not rigidly coupled together.

The flexural element portion <NUM> can include various structures extending between the neck portion <NUM> and the collar portion <NUM>. For example, as shown in FIGS. 2A-2D and 3A-3D, the flexural element portion <NUM> can include an annular portion <NUM> (e.g., a flange or rim) and beam <NUM> extending between and interconnecting the neck portion <NUM> and the collar portion <NUM>. Although four beams <NUM> are shown in <FIG>, <FIG>, and <FIG>, in practice, the flexural element portion <NUM> any number of beam <NUM> (e.g., one, two, three, or more slots). In some cases, the flexural element portion <NUM> can have no beams at all, and the annular portion <NUM> alone can extend along from the neck portion <NUM> to the collar portion <NUM>. Further still, in some cases, the flexural element portion <NUM> does not include an annular portion <NUM> at all (e.g., each of the beams <NUM> can extend from the neck portion <NUM> directly to the collar portion <NUM>). Other configurations also can be used to vary the stiffness of the flexural element portion <NUM>.

In some cases, the mechanical joint <NUM> can be rotationally symmetric about the longitudinal axis <NUM>. In some cases, the mechanical joint <NUM> can have at least four-fold rotational symmetry about the longitudinal axis <NUM>.

In some cases, the mechanical joint <NUM> can have directionally dependent stiffness. For example, referring to <FIG>, the mechanical joint <NUM> can have a first translational stiffness kz with respect to the longitudinal axis <NUM> (i.e., the z-axis), a second translational stiffness kx with respect to the x-axis, and a third translational stiffness ky with respect to the y-axis (where the x, y, and z axes refer to the axes of a Cartesian coordinate system). The first translational stiffness kz can be different than each of the second translational stiffness kx and the third translational stiffness ky. For example, the first translational stiffness kz can be greater than each of the second and third translational stiffnesses kx and ky. Further, in some cases, the second translational stiffness kx and the third translational stiffness ky can be substantially the same.

Further, the mechanical joint <NUM> can have a first rotational stiffness kθx about the x-axis, a second rotational stiffness kθy about the y-axis. The first and second rotational stiffnesses kθx and kθy can be substantially the same, and each rotational stiffness can be less than the first transitional stiffness kz.

This combination of stiffnesses can be useful, for example, as it enables the mechanical joint <NUM> to couple force from the actuator <NUM> uniformly with respect to the x-y plane, such that the waveguide <NUM> less likely to exhibit directionally-dependent bias with respect to the x-y plane during operation of the actuator <NUM>. Thus, the waveguide <NUM> is more likely to travel along a predictable predefined scan pattern, thereby improving the projected image quality. Further, as the first translation stiffness kz is relatively large, the waveguide <NUM> is less along to translate along the z-axis, while still enabling it vibrate with respect to the x and y axes.

Further still, in some cases, the stiffnesses can be modified to vary the behavior of the waveguide <NUM> (e.g., to increase or decrease the deflection angle of the waveguide tip <NUM> during operation of the actuator <NUM> and/or to change the natural or resonant frequency of the waveguide tip <NUM> during operation). Thus, the performance of the FSD device <NUM> can be adjusted by modifying the stiffnesses of the mechanical joint <NUM>. In some cases, the mechanical joint <NUM> enables the waveguide tip <NUM> to scan a pattern at a frequency of approximately <NUM> to <NUM> and to achieve a diametral deflection between <NUM> and <NUM> (e.g., the tip <NUM> of traverses a circular or substantially circular path having a diameter between <NUM> and <NUM>). Other performance characteristics are also possible, depending on the implementation.

As examples, in some cases, a typical radial translation stiffness can be between <NUM> N/mm and <NUM> N/mm, with a buckling mode stiffness between <NUM> N/mm and <NUM> N/mm. In some cases, a typical axial translation stiffness can be between <NUM> N/mm and <NUM> N/mm, with a buckling mode stiffness between <NUM> N/mm and <NUM> N/mm. In some cases, a typical rotational stiffness can be between <NUM> N*mm/Rad and <NUM> N*mm/Rad, with a buckling mode stiffness between <NUM> N*mm/Rad and <NUM> N*mm/Rad.

In some cases, each slot <NUM> can be radially aligned with a corresponding slot <NUM> and a corresponding beam <NUM>. For example, as shown in <FIG> and <FIG>, a first slot 220a, a first slot 230a, and a first beam 234a are each disposed at a first radial direction 402a with respect to the longitudinal axis <NUM>. Further, a second slot 220b, a second slot 230b, and a second beam 234b are each disposed at a second radial direction 402b with respect to the longitudinal axis <NUM>. Further, a third slot 220c, a third slot 230c, and a third beam 234c are each disposed at a third radial direction 402c with respect to the longitudinal axis <NUM>. Further, a fourth slot 220d, a fourth slot 230d, and a fourth beam 234d are each disposed at a fourth radial direction 402d with respect to the longitudinal axis <NUM>.

Further, the directions can be evenly azimuthally spaced around the longitudinal axis <NUM>. For example, as shown in <FIG> and <FIG>, the radial directions 236a-d are azimuthally spaced in <NUM>° increments with respect to the longitudinal axis <NUM>.

In some cases, the radial directions 236a-d can each align with a respective piezoelectric element of the actuator <NUM>. For instance, in the example shown in <FIG>, the actuator <NUM> includes four lines of piezoelectric elements (e.g., piezo-ceramic elements) that are evenly azimuthally spaced about the longitudinal axis <NUM>, and electrode plates disposed between adjacent piezoelectric elements (due to the perspective view of <FIG>, only two piezoelectric elements 404a and 404b, and three electrode plates 406a-c are shown). As shown in <FIG>, the first radial direction 402a can be radially aligned with a first piezoelectric element 404a, and the second radial direction 402b can be radially aligned with a second piezoelectric element 404b. Similarly, the third radial direction 402c and the fourth radial direction 402d can each be radially aligned with a third piezoelectric element and a fourth piezoelectric element, respectively.

This configuration can be useful, for example, to define the axes of motion of the FSD device <NUM> and/or to reduce directionally-dependent bias with respect to the x-y plane during operation of the actuator <NUM>.

Although an example configuration of a mechanical joint <NUM> is shown in <FIG>, <FIG>, <FIG>, and <FIG>, this is merely an illustrative example. In practice, the configuration of a mechanical joint can differ, depending on the application (e.g., to accommodate differently sized actuators and/or waveguides, to provide different stiffness properties, to provide different waveguide deflection characteristics, etc.).

As an example, <FIG> show another mechanical joint <NUM>. <FIG> shows a perspective view of the mechanical joint <NUM>, <FIG> shows a top view of the mechanical joint <NUM>, and <FIG> shows a cross-sectional view of the mechanical joint <NUM> along the plane A.

The mechanical joint <NUM> is similar in some respects to the mechanical joint <NUM>. For example, the mechanical joint <NUM> includes a neck portion <NUM>, a collar portion <NUM>, and a flexural element portion <NUM>. The neck portion <NUM> is configured to mechanically couple to a waveguide (e.g., the waveguide <NUM>) through a mechanical and/or chemical attachment between them. Further, the collar portion <NUM> is configured to mechanically couple to an actuator (e.g., the actuator <NUM>). Further, the flexural element portion <NUM> is configured to mechanically couple the neck portion <NUM> to the collar portion <NUM>, such that forces imparted onto the collar portion <NUM> (e.g., due to vibrations generated by an actuator) are coupled to the neck portion <NUM>.

The flexural element portion <NUM> also includes an annular portion <NUM> (e.g., a flange or rim) extending between and interconnecting the neck portion <NUM> and the collar portion <NUM>. A number of slots can be defined on the annular portion <NUM>. For example, as shown in <FIG>, three slots <NUM> can be defined on the annular portion <NUM>, each extending spirally outward from the neck portion <NUM>. The slots <NUM> can be rotationally symmetrically defined about the longitudinal axis <NUM> of the mechanical joint <NUM> (e.g., each slot <NUM> can be rotationally offset from an adjacent slot <NUM> by <NUM>°). Although three slots <NUM> are shown in <FIG>, this is merely an illustrative example. In practice, a mechanical joint can include any number of slots <NUM> (e.g., one, two, three, four, or more).

Further, as shown in <FIG>, the slots <NUM> are confined within a notional circle B. In practice, the size of the circle B can differ, such that the slots <NUM> occupy a greater or lesser area of the annular portion <NUM>.

Further, as shown in <FIG> and <FIG>, the mechanical joint <NUM> also includes a hub step structure <NUM>. The hub step structure <NUM> extends outward from the flexural element portion <NUM>, and encircles the neck portion <NUM>, forming a step or indentation <NUM>. The hub step structure <NUM> can be useful, for example, in providing additional stiffness to the mechanical joint <NUM>.

<FIG> show another example mechanical joint <NUM>. <FIG> shows a perspective view of the mechanical joint <NUM>, <FIG> shows a top view of the mechanical joint <NUM>, and <FIG> shows a cross-sectional view of the mechanical joint <NUM> along the plane A.

The mechanical joint <NUM> also includes a hub step structure <NUM>. The hub step <NUM> structure includes several finger structures <NUM>, each extending outward from the flexural element portion <NUM>. For example, as shown in <FIG> and <FIG>, the mechanical joint <NUM> can include eight finger structures <NUM> that protrude from the flexural element portion <NUM> and encircle the neck portion <NUM>. The finger structures <NUM> can be rotationally symmetrically disposed about the longitudinal axis <NUM> of the mechanical joint <NUM> (e.g., each finger structure <NUM> can be rotationally offset from an adjacent finger structure <NUM> by <NUM>°). Although either finger structures <NUM> shown in <FIG>, this is merely an illustrative example. In practice, a mechanical joint can include any number of finger structures <NUM> (e.g., one, two, three, four, or more).

Further, the finger structure <NUM> form a step or indentation <NUM>. In a similar manner as described with respect to <FIG>, the hub step structure <NUM> can be useful, for example, in providing additional stiffness to the mechanical joint <NUM>.

<FIG> show another example mechanical joint <NUM>. <FIG> shows a perspective view of the mechanical joint <NUM>, <FIG> shows a top view of the mechanical joint <NUM>, and <FIG> shows a cross-sectional view of the mechanical joint <NUM> along the plane D.

The mechanical joint <NUM> includes a neck portion <NUM>, a collar portion <NUM>, and a gimbal structure <NUM>. The neck portion <NUM> is configured to mechanically couple to a waveguide (e.g., the waveguide <NUM>) through a mechanical and/or chemical attachment between them. Further, the collar portion <NUM> is configured to mechanically couple to an actuator (e.g., the actuator <NUM>).

Further, the gimbal structure <NUM> is configured to mechanically couple the neck portion <NUM> to the collar portion <NUM>, such that forces imparted onto the collar portion <NUM> (e.g., due to vibrations generated by an actuator) are coupled to the neck portion <NUM>. The gimbal structure <NUM> includes a ring <NUM>, inner beams <NUM> mechanically coupling the ring <NUM> to the neck portion <NUM>, and outer beams <NUM> mechanically coupling the ring <NUM> to the collar portion <NUM>.

As shown in <FIG>, the ring <NUM> is ovular in shape, and is centered about a longitudinal axis <NUM> of the mechanical joint <NUM>. The inner beams <NUM> extend inward from the inner periphery of the ring <NUM> along the major axis <NUM> of the ring <NUM>. The outer beams <NUM> extend outward from the outer periphery of the ring <NUM> along the minor axis <NUM> of the ring <NUM>. Further, the major axis <NUM> is orthogonal to the minor axis <NUM>. Thus, the inner beams <NUM> and the outer beams <NUM> are rotationally from one another by <NUM>°.

The gimbal structure <NUM> enables the neck portion <NUM> to rotate with respect to the collar portion <NUM> substantially about two discrete axes of rotation (e.g., about the major axis <NUM> and about the minor axis <NUM>). For example, as the ring <NUM> is mechanically coupled to the collar portion <NUM> through the outer beams <NUM>, the ring <NUM> can rotate relative to the collar portion <NUM> about minor axis <NUM>. This rotation, in turn, similarly rotates the neck portion <NUM> relative to the collar portion <NUM> about the minor axis <NUM>. Further, as the ring <NUM> is mechanically coupled to the neck portion <NUM> through the inner beams <NUM>, the neck portion <NUM> can rotate relative to the ring <NUM> about the major axis <NUM>.

This arrangement confines the movement of the neck portion <NUM> relative to the collar portion <NUM> along a discrete number of rotational axes. This can be useful, for example, in improving the operational characteristics of the mechanical joint (e.g., by eliminating or otherwise reducing errant movement along other axes of rotation).

Although example mechanical joints are depicted herein, it is understood that they are not necessarily drawn to scale. In practice, the dimensions of each structure of a mechanical joint can vary, depend on the application. As examples, various dimensions of a mechanical joint are described below. However, it is understood that, in practice, other dimensions are also possible.

In some cases, an inner diameter of a collar portion can be between <NUM> and <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>). In some cases, an outer diameter of a collar portion can be between <NUM> and <NUM> (e.g., <NUM>, <NUM> <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>).

In some cases, an inner diameter of a neck portion can be between <NUM> and <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>). In some cases, an outer diameter of a neck portion can be <NUM> or less (e.g., <NUM>, <NUM>, <NUM>, and <NUM>).

In some cases, an inner diameter of a hub step structure can be between <NUM> and <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>). In some cases, a diametrical thickness of a hub step structure can be between <NUM> and <NUM> (e.g., <NUM> and <NUM>).

In some cases, a thickness of a flexural element portion can be between <NUM> and <NUM> (e.g., <NUM> and <NUM>).

In some cases, a thickness of an inner beam of a gimbal structure (e.g., in a direction orthogonal to the longitudinal axis of the mechanical joint) can be between <NUM> and <NUM> (e.g., <NUM> and <NUM>). In some cases, a thickness of an outer beam of a gimbal structure (e.g., in a direction orthogonal to the longitudinal axis of the mechanical joint) can be between <NUM> and <NUM> (e.g., <NUM> and <NUM>). In some cases, the length of an outer beam of a gimbal structure (e.g., in another direction orthogonal to the longitudinal axis of the mechanical joint) can be between <NUM> and <NUM> (e.g., <NUM> and <NUM>).

In some cases, a thickness of a spirally extending slot defined along a flexural element portion can be between <NUM> and <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>). In some cases, spirally extending slots can be parametrically defined by the equations: x(t) = (A<NUM> + B<NUM> * T * π/<NUM>) * (cos (T * π/<NUM>)/ <NUM> and y(t) = (A<NUM> + B<NUM> * T * π/<NUM>) * (sin (T * π/<NUM>)/<NUM>, where <NUM> ≤ T ≤ θf. A<NUM> can be between <NUM> and <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>). B<NUM> can be between <NUM> and <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>). θf can be between <NUM> and <NUM>° (e.g., <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°).

Further, although various structures are depicted herein, it is understood that various features can be combined onto a single mechanical joint, and/or excluded from a mechanical joint. As an example, a mechanical joint can include one or more of spirally extending slots defined on a flexural element portion (e.g., as shown in <FIG>), a hub step structure (e.g., as shown in <FIG> and <FIG>), a hub step structure having finger structures (e.g., as shown in <FIG>), a gimbal structure (e.g., as shown in <FIG>), slots defined on a collar portion (e.g., as shown in <FIG>), slots defined on a neck portion (e.g., as shown in <FIG>), or any combination thereof.

A mechanical joint can be constructed using various materials. For example, in some cases, the mechanical joint can be constructed, either partially or entirely, of silicon. In some cases, the mechanical joint can be construed using a crystalline silicon (e.g., silicon having a (<NUM>) crystal structure) and/or an amorphous silicon. In some cases, the mechanical joint can be constructed using one or more layers of silicon and/or one or more layers of an electrically insulative material (e.g., silicon dioxide).

In some cases, a mechanical joint can be construed using semiconductor microfabrication techniques. A simplified example in shown in <FIG>.

As an example, <FIG> shows a cross-sectional view of a wafer <NUM>. The wafer <NUM> includes a device layer <NUM> (e.g., a layer of silicon), a buried oxide layer <NUM> (e.g., a layer of silicon dioxide), and a handle layer <NUM> (e.g., a layer of silicon). These layers can be formed, for example, by depositing each of the layers in succession onto a substrate (e.g., using oxidation, physical vapor deposition, chemical vapor deposition, electroplating, spin casting, or other layer deposition techniques).

One or more features can be defined on the wafer <NUM> by selectively adding and/or removing material from the wafer <NUM>. For example, as shown in <FIG>, material can be etched from the wafer <NUM> to define channels <NUM>.

Material from the wafer <NUM> can be added and/or removed in such a way that the remaining material forms the mechanical joint. For example, as shown in <FIG>, material can be selectively removed along the periphery of the wafer <NUM>, such that a substantially cylindrical portion of the wafer <NUM> remains, forming the outer periphery of the outer wall <NUM> of the collar portion <NUM> of the mechanical joint <NUM>. Further, material can be selectively removed along the interior of the wafer <NUM> to define the inner channels <NUM> and <NUM>. In a similar manner, additional material can be removed from the wafer <NUM> to define each of the other structures of the mechanical joint <NUM>. As an example, wafer <NUM> can be etched using photolithography techniques (e.g., wet etching or dry etching, such as reactive-ion-etching and deep-reactive-ion etching).

Producing a mechanical joint using microfabrication techniques can provide various benefits. For example, in some cases, mechanical joints can be constructed precisely and consistently, and thus may be suitable for use in variation-specific applications (e.g., in imaging systems that may be highly sensitive to the properties of a mechanical joint, such as FSD devices). Further, mechanical joints can be readily mass produced. Further still, the design of mechanical joints can be readily modified and implemented, and thus can be readily used in a variety of different applications.

Although an example microfabrication process is shown <FIG>, this is merely a simplified example. In practice, other microfabrication techniques can be used to product a mechanical joint and/or to produce mechanical joints having different structural features that those shown herein. For example, similar techniques can also be used to form any other mechanical joint described herein (e.g., the mechanical joints <NUM>, <NUM>, and <NUM>).

Claim 1:
An apparatus, comprising:
an optical fiber (<NUM>);
an actuator (<NUM>) configured to generate a force to vary an orientation of a first end (<NUM>) of the optical fiber (<NUM>); and
a joint (<NUM>, <NUM>, <NUM>, <NUM>) mechanically coupling the actuator (<NUM>) to the optical fiber (<NUM>), wherein the joint (<NUM>, <NUM>, <NUM>, <NUM>) is configured to couple the force generated by the actuator (<NUM>) to the optical fiber (<NUM>), and wherein the joint (<NUM>, <NUM>, <NUM>, <NUM>) comprises:
a neck (<NUM>, <NUM>, <NUM>, <NUM>) extending along an axis (z, <NUM>, <NUM>, <NUM>, <NUM>), the optical fiber (<NUM>) being threaded through an aperture extending along the axis (z, <NUM>, <NUM>, <NUM>, <NUM>) through the neck (<NUM>, <NUM>, <NUM>, <NUM>), wherein the optical fiber (<NUM>) is attached to the joint (<NUM>, <NUM>, <NUM>, <NUM>) at a surface of the neck (<NUM>, <NUM>, <NUM>, <NUM>) facing the axis (z, <NUM>, <NUM>, <NUM>, <NUM>),
a collar (<NUM>, <NUM>, <NUM>, <NUM>) extending along the axis (z, <NUM>, <NUM>, <NUM>, <NUM>), wherein the actuator (<NUM>) is mechanically attached to the joint (<NUM>, <NUM>, <NUM>, <NUM>) at an inner surface (<NUM>) of the collar (<NUM>, <NUM>, <NUM>, <NUM>) facing the axis, and
a flexural element (<NUM>, <NUM>, <NUM>) extending radially from the neck (<NUM>, <NUM>, <NUM>, <NUM>) to the collar (<NUM>, <NUM>, <NUM>, <NUM>),
wherein the joint (<NUM>, <NUM>, <NUM>, <NUM>) has a first stiffness (kz) with respect to the axis (z, <NUM>, <NUM>, <NUM>, <NUM>), a second stiffness (kx) with respect to a first radial direction (x, 402a), and a third stiffness (ky) with respect to a second radial direction (y, 402b) orthogonal the first radial direction (x, 402a), and
wherein the first stiffness (kz) is greater than the second stiffness (kx) and the third stiffness (ky).