CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No. 63/371,688 filed on August 17, 2022, entitled “SMARTGLASSES TWO-DIMENSIONAL (2D) HINGE WITH ASYMMETRIC VERTICAL DEFLECTIONS,” the disclosure of which is incorporated herein in its entirety.

TECHNICAL FIELD

[0002] This description relates in general to head mounted wearable devices, and in particular, to head mounted wearable computing devices including a display device.

BACKGROUND

[0003] Eyewear in the form of glasses may be worn by a user to, for example, provide for vision correction, reduce the effect of sunlight and/or glare, provide a measure of safety, and the like. These types of eyewear are typically somewhat flexible and/or deformable, so that the eyewear can be manipulated to comfortably fit the user. In some situations, an ophthalmic technician may manipulate rim portions and/or arm portions of a frame of the eyewear, for example, through cold working the frame and/or heating and re-working the frame, to adjust the eyewear to meet the needs of a particular user. In some situations, this re-working of the frame may occur over time, through continued use/wearing of the eyewear by the user. Manipulation in this manner, due to the flexible and/or deformable nature of the material of the frame and/or the lenses of the eyewear, may provide a comfortable fit while still maintaining ophthalmic alignment between the eyewear and the user. In a situation in which the eyewear is a head mounted wearable device including display capability and processing/computing capability, such as, for example, smart glasses, this type of flexibility and/or deformation in the frame may cause inconsistent alignment of the display, or misalignment of the display. Inconsistent alignment, or misalignment of the display can result in inconsistent alignment, or misalignment, of content output by the display, relative to an eye box, or a field of view of the user. This may cause visual discomfort, particularly in the case of a binocular display. SUMMARY

[0004] A head mounted wearable device, in accordance with implementations described herein, includes dual axis hinge mechanisms coupling arm portions to a front frame portion of a frame of the head mounted wearable device. The dual axis hinge mechanism is operable in a first mode providing for rotation of the arm portions about a first axis of rotation, and in a second mode providing for rotation of the arm portions about a second axis of rotation. The dual axis hinge mechanism incorporates a torque control feature that reduces or substantially eliminates the transfer of loads, for example torque loads, from the arm portions into the front frame portion of the frame due to deflection of one or both of the arm portions. A frame of a head mounted wearable device including the dual axis hinge mechanism, in accordance with implementations described herein, allows for deflection of the arm portions with respect to the front frame portion, without the transfer of loads to the front frame portion. This avoids twisting or bending of the front frame portion, allowing the front frame portion to maintain its initial, at-rest state. [0005] In some aspects, the techniques described herein relate to a head mounted wearable device, including a frame, including a front frame portion; at least one arm portion coupled to the front frame portion; and a hinge mechanism rotatably coupling the at least one arm portion to the front frame portion, wherein in a first mode of operation, the hinge mechanism provides for rotation of the at least one arm portion about a first axis of rotation; and in a second mode of operation, the hinge mechanism provides for rotation of the at least one arm portion about a second axis of rotation. Tn particular, the hinge mechanism is configured to provide for rotation of the arm portions about a first axis of rotation and about a second axis of rotation, the orientation of the first axis of rotation being different from the orientation of the second axis of rotation. For example, the first axis runs essentially vertically (when the head mounted wearable device is worn by a user with straight head position). The second axis may extend obliquely or perpendicular to the first axis.

[0006] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein the hinge mechanism includes a first hinge device rotatably coupling the at least one arm portion to the front frame portion about the first axis of rotation; and a second hinge device rotatably coupling the at least one arm portion to the front frame portion about the second axis of rotation, wherein the second hinge device defines a torque control feature of the hinge mechanism that controls a load transferred from the at least one arm portion to the front frame portion in response to a deflection of the at least one arm portion.

[0007] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein the first hinge device and the second hinge device are independently operable, the first hinge device being operable in the first mode of operation of the hinge mechanism, and the second hinge device being operable in the second mode of operation of the hinge mechanism.

[0008] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein, in a first position of the at least one arm portion, a mating surface of the at least one arm portion abuts a mating surface of the front frame portion, defining a stopping mechanism that restricts movement of the at least one arm portion in a first rotational direction of the at least one arm portion about the second axis of rotation, and in a second position of the at least one arm portion, the at least one arm portion is rotated away from the front frame portion in a second rotational direction about the second axis of rotation, such that mating surface of the at least one arm portion is separated from the mating surface of the front frame portion, in response to a deflection force applied to the at least one arm portion.

[0009] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein the second axis of rotation is substantially orthogonal to the first axis of rotation.

[0010] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein the at least one arm portion includes a first arm portion and a second arm portion, and wherein the hinge mechanism includes a first hinge mechanism rotatably coupling the first arm portion to a first end portion of the front frame portion about the first axis of rotation; and a second hinge mechanism rotatably coupling the second arm portion to a second end portion of the front frame portion about the second axis of rotation.

[0011] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein, in the second mode of operation, the first arm portion is positioned in a first position by the first hinge mechanism in response to a force applied to the first arm portion, and the second arm portion is positioned in a second position by the second hinge mechanism in response to the force applied to the first arm portion, wherein the positioning of the second arm portion by the second hinge mechanism is asymmetric to the positioning of the first arm portion by the first hinge mechanism in response to the force applied to the first arm portion. For example, the positioning of the second arm portion by the second hinge mechanism is asymmetric to the positioning of the first arm portion by the first hinge mechanism with respect to a symmetry plane which extends through a middle portion of the front frame portion and essentially perpendicular to the front frame portion.

[0012] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein, in the second mode of operation, in response to a force applied the first arm portion in a first direction, the first arm portion is configured to rotate in a first rotational direction about the second axis of rotation of the first hinge mechanism, such that the first arm portion is displaced in the first direction; and the second arm portion is configured to rotate in a second rotational direction about the second axis of rotation of the second hinge mechanism, with rotation of the second arm portion in the second rotational direction restricted by a stopping mechanism defined by a mating surface of the second arm portion abutting a mating surface of the front frame portion.

[0013] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein, in response to a deflection force exerted on one of the first arm portion or the second arm portion, at least one of the first arm portion or the second arm portion rotates about the second axis of rotation. The deflection force is not transferred to the front frame portion in response to the rotation of at least one or the first arm portion or the second arm portion.

[0014] In some aspects, the techniques described herein relate to a head mounted wearable device, wherein the first axis of rotation is a vertical axis of rotation, in the first mode of operation, the first hinge mechanism and the second hinge mechanism provide for horizontal rotation of the first arm portion and the second arm portion relative to the front frame portion to open and close the frame, the second axis of rotation is a horizontal axis of rotation, and in the second mode of operation, the first hinge mechanism and the second hinge mechanism are independently operable to provide for vertical rotation of the first arm portion and the second arm portion relative to the front frame portion.

[0015] In some aspects, the techniques described herein relate to a head mounted wearable device, further including a display device coupled in or on the frame and configured to output augmented reality content at at least one lens portion held in the front frame portion of the frame. [0016] In some aspects, the techniques described herein relate to a hinge mechanism for a head mounted wearable device, in particular, a head mounted wearable device as described herein, the hinge mechanism including a first hinge device rotatably coupling at least one arm portion to a front frame portion of a frame of the head mounted wearable device; and a second hinge device rotatably coupling the at least one arm portion to the front frame portion, and providing for rotation of the at least one arm portion relative to the front frame portion about a second axis of rotation, wherein in a first mode, the first hinge device provides for rotation of the at least one arm portion relative to the front frame portion about a first axis of rotation, and in a second mode, the second hinge device provides for rotation of the at least one arm portion relative to the front frame portion about a second axis of rotation in response to a deflection force applied to the at least one arm portion, the second axis of rotation being substantially orthogonal to the first axis of rotation.

[0017] In some aspects, the techniques described herein relate to a hinge mechanism, wherein the at least one arm portion includes a first arm portion and a second arm portion, and wherein the hinge mechanism includes a first hinge mechanism rotatably coupling the first arm portion to a first end portion of the front frame portion about the first axis of rotation; and a second hinge mechanism coupling the second arm portion to a second end portion of the front frame portion about the second axis of rotation, and in the second mode, the first arm portion is positioned in a first position by the first hinge mechanism in response to a force applied to the first arm portion, and the second arm portion is positioned in a second position by the second hinge mechanism in response to the force applied to the first arm portion, wherein the positioning of the second arm portion by the second hinge mechanism is asymmetric to the positioning of the first arm portion by the first hinge mechanism in response to the force applied to the first arm portion.

[0018] In some aspects, the techniques described herein relate to a hinge mechanism, wherein the first axis of rotation is a vertical axis of rotation, and in the first mode, the first hinge mechanism and the second hinge mechanism provide for horizontal rotation of the first arm portion and the second arm portion relative to the front frame portion to open and close the frame, and the second axis of rotation is a horizontal axis of rotation, and in the second mode, the first hinge mechanism and the second hinge mechanism are independently operable to provide for vertical rotation of the first arm portion and the second arm portion relative to the front frame portion.

[0019] In some aspects, the techniques described herein relate to a hinge mechanism, wherein, in a first position of the at least one arm portion, a mating surface of the at least one arm portion abuts a mating surface of the front frame portion, defining a stopping mechanism that restricts movement of the at least one arm portion in a first rotational direction of the at least one arm portion about the second axis of rotation, and in a second position of the at least one arm portion, the at least one arm portion is rotated away from the front frame portion about the second axis of rotation, in a second rotational direction, such that mating surface of the at least one arm portion is separated from the mating surface of the front frame portion, in response to a deflection force applied to the at least one arm portion.

[0020] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 A illustrates an example head mounted wearable device worn by a user.

[0022] FIG. IB is a front view, and FIG. 1C is a rear view, of the example head mounted wearable device shown in FIG. 1 A.

[0023] FIG. 2 illustrates an example system for durability testing of eyewear.

[0024] FIG. 3 A is a schematic perspective view, FIG. 3B is a schematic top view, and FIG 3C is a schematic side view, of a sample head mounted wearable device in an at-rest state. [0025] FIG. 4A is a schematic perspective view, FIG. 4B is a schematic top view, and FIG 4C is a schematic side view, of the sample head mounted wearable device shown in FIGs. 3A-3C, in a flexed state.

[0026] FIG. 5 illustrates a distribution of yield stress in a sample frame having a rigid front frame portion, after durability testing.

[0027] FIGs. 6A is a top view of the sample frame shown in FIGs. 3A-4C, illustrating moment forces generated in response to deflection of an arm portion of the sample frame.

[0028] FIG. 6B is a graph of moment forces as a function of deflection angle of the arm portion of the sample frame.

[0029] FIG. 7A is a perspective view of an example frame of an example head mounted wearable device. [0030] FTG. 7B is a first schematic side view, and FIG 7C is a second schematic side view, of an example dual axis hinge mechanism the example frame shown in FIG. 7A.

[0031] FIG. 7D is a schematic side view of the example frame shown in FIGs. 7A-7C, in response to a first deflection force exerted on an arm portion of the example frame.

[0032] FIG. 7E is a schematic side view of the of the example frame shown in FIGs. 7A- 7C, in response to a second deflection force applied to an arm portion of the example frame.

[0033] FIG. 8A is a first schematic side view, and FIG. 8B is a second schematic side view, illustrating operation of an example dual axis hinge mechanism in response to a force exerted on one arm portion of an example frame.

[0034] FIG. 9A is a first schematic side view, and FIG. 9B is a second schematic side view, illustrating operation of an example dual axis hinge mechanism in response to a force applied to one arm portion of an example frame.

DETAILED DESCRIPTION

[0035] This disclosure relates to mechanisms for eyewear, and in particular, for eyewear including display capability and/or computing/processing capability, that allow for flexibility in some portions of the eyewear, while maintaining rigidity in other portions of the eyewear.

Rigidity in some portions of the eyewear, such as, for example, a front frame portion of a frame of the eyewear, may maintain display alignment to, in turn, maintain integrity of content output by a display device of the eyewear, and maintain visual comfort for the user. That is, rigidity in the front frame portion of the eyewear may maintain alignment of content output by the display device within a field of view of the user. In some examples, rigidity in the front frame portion of the eyewear may maintain alignment of content within an eye box coincident with one or both lenses of the eyewear.

[0036] A head mounted wearable device, in accordance with implementations described herein, includes hinge mechanisms coupling arm portions, including a first arm portion and a second arm portion, with a corresponding end portion of the front frame portion of the frame of the head mounted wearable device. In some examples, each of the hinge mechanisms is a dual axis hinge mechanism that is operable in a first mode and a second mode. In the first mode of operation, the hinge mechanism provides for rotation of the arm portion about a first axis of rotation. Tn the second mode of operation, the hinge mechanism provides for rotation of the arm portion about a second axis of rotation. In some examples, the hinge mechanism includes a first hinge device and a second hinge device. In some examples, the first hinge device provides for a rotating movement of the arm portion about the first axis of rotation, and the second hinge device provides for a rotating movement of the arm portion about the second axis of rotation. In some examples, the second axis of rotation is substantially orthogonal to the first axis of rotation. In some examples, each of the hinge mechanisms includes a torque control feature that reduces or substantially eliminates the transfer of loads, for example torque loads, from the arm portions into the front frame portion of the frame due to deflection of one or both of the arm portions. In some examples, the torque control feature is defined by the second hinge mechanism. A frame of a head mounted wearable device including hinge mechanisms, in accordance with implementations described herein, coupling the first and second arm portions to the front frame portion of the frame, allow for deflection of the arm portions with respect to the front frame portion. In some examples, the hinge mechanism allows for the deflection of the arm portions independent from an opening and closing rotation motion of the arm portions with respect to the front frame portion of the frame.

[0037] Eyewear, or glasses, are typically somewhat flexible and/or deformable, so that the eyewear can be manipulated to adapt to a particular head size and/or shape, a particular arrangement of features, a preferred pose of the eyewear on the face of the user, a position of the eyewear on the nose of the user, and the like, to provide a comfortable fit for the user. The flexible or deformable characteristics of the material of the frame of the eyewear may allow the eyewear to be customized (i.e., by a user and/or by a technician) to fit a particular user, while still maintaining the functionality of the eyewear. Similarly, the flexible or deformable characteristics of the material of the frame of the eyewear may allow the eyewear to maintain its functionality over time. For example, deformation (bending, flexing, twisting and the like) over time due to wear, use and the like may cause permanent deformation of the frame that, in many instances, will not affect the functionality of the eyewear.

[0038] The ability to flex, or deform and maintain functionality as described above may be designed into traditional ophthalmic eyewear, such that deformation and/or flex and/or twist in the frame does not adversely affect functionality of the eyewear such as, for example, vision correction. In a situation in which the eyewear is in the form of smart glasses that include a display device, as well as other electronic components (for example, to support computing/processing capability), flex or deformation of the frame may not provide the desired structural support for electronic components coupled to and/or housed in the frame. Similarly, flex or deformation of the frame of a pair of smart glasses may not provide for and/or maintain the alignment of content output by the display device with an eye box and/or output coupler that would otherwise ensure that the content is visible to the user.

[0039] FIG. 1A illustrates a user wearing an example head mounted wearable device 100. The example head mounted wearable device 100 shown in FIG. 1A is in the form of smart glasses, or augmented reality glasses, including display capability and computing/processing capability, for purposes of discussion and illustration. The principles to be described herein may be applied to other types of eyewear, both with and without display capability and/or computing/processing capability. FIG. IB is a front view, and FIG. 1C is a rear view, of the example head mounted wearable device 100 shown in FIG. 1A.

[0040] As shown in FIGs. 1A-1C, the example head mounted wearable device 100 includes a frame 190. The frame 190 includes a front frame portion 102 defined by rim portions

103 surrounding respective optical portions in the form of lenses 107, with a bridge portion 109 connecting the rim portions 103. Arm portions 105 are coupled, for example, pivotably or rotatably coupled, to the front frame portion 102 by hinge portions 110 at the respective rim portion 103. In some examples, the lenses 107 may be corrective/prescription lenses. In some examples, the lenses 107 may be an optical material including glass and/or plastic portions that do not necessarily incorporate corrective/prescription parameters.

[0041] In some examples, a display device 104 is coupled in a portion of the frame 190 to output content for viewing by the user at one or both of the lens(es) 107. An eye box may extend toward one or both of the lens(es) 107, for output of content at an output coupler 144 at which content output by the display device 104 is visible to the user. In some examples, the output coupler 144 is substantially coincident with the lens(es) 107. In some examples, the display device 104 includes a see-through near-eye display. For example, the display device

104 may be configured to project light from a display source onto a portion of teleprompter glass functioning as a beamsplitter seated at an angle (e.g., 30-45 degrees). The beamsplitter may allow for reflection and transmission values that allow the light from the display source to be partially reflected while the remaining light is transmitted through. Such an optic design may allow a user to see both physical items in the world, for example, through the lenses 107, next to content (for example, digital images, user interface elements, augmented reality content, virtual content, and the like) output by the display device 104. In some implementations, waveguide optics may be used to output content by the display device 104. [0042] In some examples, the head mounted wearable device 100 includes at least one gaze tracking device 120. The at least one gaze tracking device 120 may include at least one sensor 125 to detect and track eye gaze direction and movement. Data captured by the sensor(s) 125 may be processed to detect and track gaze direction and movement as a user input. In some examples, the head mounted wearable device 100 includes multiple gaze tracking devices 120 to track gaze direction and movement of both eyes of the user.

[0043] In some examples, the head mounted wearable device 100 can also include an audio output device 106 (such as, for example, one or more speakers), an illumination device 108, a sensing system 111, a control system 112, at least one processor 114, and an outward facing image sensor 116, or camera. In some examples, the sensing system 111 includes various sensing devices and the control system 112 includes various control system devices including, for example, one or more processors 114 operably coupled to the components of the control system 112. In some examples, the control system 112 includes a communication module providing for communication and exchange of information between the head mounted wearable device 100 and other external devices.

[0044] In some examples, at least some portions of the frame 190 are made of rigid materials and/or components. Rigidity in these portion(s) of the frame 190 maintains alignment of content output by the display device(s) 104 and/or accommodates electronic components included in and/or coupled to the frame 190. In some examples, the frame 190 may be designed to provide some amount of flexure in certain portions of the frame 190, to allow the frame 190 to be comfortably worn by a variety of users. Some degree of flexure in certain portions of the frame 190 may allow the head mounted wearable device 100 (in the form of smart glasses as shown in this example) to also include the functionality of traditional ophthalmic eyewear. Including the functionality of traditional ophthalmic eyewear (in a head mounted wearable device 100 in the form of smart glasses) requires that the frame 190 meet established standards for flexure in ophthalmic eyewear, while also providing the rigidity in remaining portions of the frame 190 necessary to maintain alignment of the display device(s) 104 and/or support for the electronic components. In order to include the functionality of traditional ophthalmic eyewear, the frame 190 is held to similar standards for durability to that of traditional ophthalmic eyewear, including response to deformation due to repeated flexure over time.

[0045] FIG. 2 illustrates an example system 290 for assessing the durability of a frame over time, through repeated cycles of deformation. The repeated cycles of deformation may include, for example, twisting motion, flexing motion, bending motion, pivoting motion and the like. If the frame 190 of the example head mounted wearable device 100 in the form of smart glasses described above with respect to FIGs. 1 A-1C is to also include the functionality of traditional ophthalmic eyewear, then the frame 190 will be expected to meet similar standards, while still providing the rigidity needed to maintain display alignment and/or structural support for the electronic components.

[0046] In FIG. 2, a sample frame 200 is mounted on the example system 290. FIGs. 3A- 3C illustrate the sample frame 200 prior to being subjected to durability testing and validation by the example system 290. In particular, FIG. 3A is a perspective view, FIG. 3B is a top view, and FIG. 3C is a side view of the sample frame 200 in an at-rest state, prior to testing and validation using the example system 290. FIGs. 4A-4C illustrate the sample frame 200 during durability testing by the example system 290. In particular, FIG. 4A is a perspective view, FIG. 4B is a top view, and FIG. 4C is a side view of the sample frame 200 is in a flexed, or deformed, state, during testing.

[0047] As shown in FIGs. 3 A-4C, the sample frame 200 includes a first rim portion 203 A and a second rim portion 203B connected by a bridge portion 209. A first lens 207A is coupled in the first rim portion 203 A, and a second lens 207B is coupled in the second rim portion 203B. The first rim portion 203 A, the second rim portion 203B, and the bridge portion 209 define a front frame portion 202 of the sample frame 200. A first arm portion 205A is rotatably coupled to the front frame portion 202 (at the first rim portion 203 A) by a first hinge portion 210A. A second arm portion 205B is rotatably coupled to the front frame portion 202 (at the second rim portion 203B) by a second hinge portion 210B.

[0048] During testing, the sample frame 200 may be subjected to various different types of motion. For example, in one mode of testing, the end portion of one or both of the arm portions 205 A, 205B may be subjected to an arcuate motion, for example, in the direction of the arrow A shown in FIG. 2, for a set number of cycles. This arcuate motion may simulate, for example, the flexing, or spreading, of the arm portions 205A, 205B to accommodate a head width, an ear position, a nose position, and the like, of a particular user, over time. In some examples, the arcuate motion may be a circular motion. In some examples, the arcuate motion may have set parameters defining, for example, an amount of horizontal displacement, an amount of vertical displacement, and the like of respective end portions of the arm portions 205A, 205B. During the application of this arcuate motion, the arm portions 205A, 205B may be coupled to a support structure of the system 290 at an intermediate location along the length of the arm portions 205A, 205B, so that there is substantially no translation along the X-axis, substantially no rotation about the Y-axis, and limited rotation at the bridge portion 209 about the Z-axis. At completion of the set number of cycles, the sample frame 200 may be considered to have been validated if the sample frame 200 meets previously set criteria that are indicative of a desired level of reliability or durability of the sample frame 200 over time. In some examples, the set criteria may include, for example, that the sample frame 200 is free of fractures, that the sample frame 200 has not deformed by greater than a set amount or magnitude from its original configuration, that the arm portions 205A, 205B can support the weight of the sample frame 200 in the open position, and other such criteria.

[0049] In the example shown in FIG. 2, the sample frame 200 is mounted on the system 290 so that the end portion of the first arm portion 205 A of the sample frame 200 is subjected to the circular motion in the direction of the arrow A. Application of the circular motion as described above may cause flexure in the sample frame 200, from the essentially at-rest configuration shown in FIGs. 3A-3C, to the configuration shown in FIGs. 4A-4C. In particular, as shown in FIGs. 4A and 4C, application of a force at the end of the first arm portion 205A and the resulting circular motion at the end of the first arm portion 205A has caused movement, or deflection, of the first arm portion 205A in the direction of the arrow B, and movement, or deflection, of the second arm portion 205B in the direction of the arrow C. Movement, or deflection, of the first and second arm portions 205A, 205B in response to the force and corresponding movement of the end of the first arm portion 205A as shown in FIG. 4A can produce some level of twist in the front frame portion 202, as shown in FIGs. 4B and 4C. In this particular example, this movement, or deflection, of the first and second arm portions 205A, 205B in response to this applied force has caused a rearward deflection of the first rim portion 203A and the first lens 207 A, and a forward deflection of the second rim portion 203B and the second lens 207B. As the first arm portion 205A is cycled (i.e., through rotation of the end portion thereof as a force is applied in the direction of the arrow A), movement of the arm portions 205A, 205B will alternate in an up-down pattern until completion of the cycling. Similarly, in response to the cycling of the first arm portion 205A, deflection of the first and second rim portions 203 A, 203B will alternate in a forward-rear deflection pattern and corresponding twisting of the front frame portion 202 until completion of the cycling.

[0050] In traditional ophthalmic eyewear, the frame may be flexible enough so as to not exceed the yield strength of the frame material. In some examples, traditional ophthalmic eyewear includes spring hinges between the front frame portion and the arm portions to provide additional flexibility. This may allow these types of frames to meet or exceed the set testing criteria described above. However, in the head mounted wearable device 100 described above with respect to FIGs. 1A-1C (including display capability and processing/computing capability, and the various associated electronic components), deformation, even elastic deformation, at the front frame portion 102 (i.e., between the first and second rim portions 103 and the first and second lenses 107) is necessarily essentially zero to maintain display alignment. That is, even if the front frame portion 102 were to return to its original configuration after flexure, the time during which the front frame portion 102 is twisted, or flexed, will disrupt the output of the display device 104 and cause visual discomfort. While rigidity of the front frame portion 102 may address this issue, allowing the front frame portion 202 to maintain its initial, undeformed state, this additional rigidity of the front frame portion 102 will result in higher stresses applied to the front frame during the type of durability testing described with respect to FIG. 2, and may result in a compromised, or broken frame 190. This type of result (i.e., compromised, or broken frame 190) will preclude the incorporation of traditional ophthalmic functionality into the head mounted wearable device 100 including display capability and processing/computing capability. FIG. 5 illustrates a sample frame 200A including a rigid front frame portion that has undergone the durability testing described above with respect to FIGS. 2-4C. In FIG. 5, the darkened areas of the rim portion indicate areas of the rim portion that have exceeded the yield strength of the material.

[0051] Accordingly, a head mounted wearable device, in accordance with implementations described herein, includes hinge mechanisms at the rotatable coupling of the arm portions to the front frame portion that incorporate a torque control feature. Hinge mechanisms, in accordance with implementations described herein, provide for some amount of flexibility to accommodate deflections of the arm portions that are typically accommodated in traditional ophthalmic eyewear by a standard hinge (which provides compliance in one axis) and/or a flexible frame. A hinge mechanism including a torque control feature, in accordance with implementations described herein, may provide for compliance in multiple axes, to decrease or substantially eliminate loads, for example, torque loads, into the front frame portion generated by larger deflections. That is, torque loads generated due to deflection of the arm portions are not transmitted to the front frame portion due to the action of the hinge mechanism. A hinge mechanism, in accordance with implementations described herein, is operable in a first mode and a second mode to provide for compliance in multiple axes. In the first mode of operation, the arm portion is rotatable about a first axis of rotation of the multiple axes. In the second mode of operation, the arm portion is rotatable about a second axis of rotation of the multiple axes, to define the torque control feature. In some examples, movement of a first arm portion of the frame is asymmetric to movement of a second arm portion of the frame in response to a deflection force applied to one of the first arm portion or the second arm portion. As illustrated in the schematic diagram shown in FIG. 6A, and the graph shown in FIG. 6B, for a deflection of the arm portion 105 in the amount of an angle 0, a moment M is generated at the corresponding hinge portion 110. When using a typical spring hinge to couple the arm portion 105 to the front frame portion 102, the moment M generated at the hinge portion 110 (and transmitted at least in part to the front frame portion 102) follows a substantially linear path as the deflection angle 0 increases, as shown in FIG. 6B. In contrast, hinge mechanisms including torque control features, in accordance with implementations described herein, may cause the moment M generated at the hinge portion 110 to dissipate, and approach zero, even as the deflection angle 0 increases. [0052] In some examples, a hinge mechanism, and in particular, a dual-axis hinge mechanism, in accordance with implementations described herein, provides for compliance in multiple axes, such that loads generated due to deflection of at least one arm portion of the frame are not transmitted to the front frame portion of the frame. In this manner, a rigidity of the front frame portion can be maintained, a twisting or bending of the front frame portion, which would cause misalignment of visual content output by the display device, can be avoided, and the initial, or at-rest configuration of the front frame portion can be maintained. In this manner, a relative position of a first rim portion/lens portion and a second rim portion/lens portion of the front frame portion as originally intended can be maintained, thus maintaining alignment for binocular output of visual content.

[0053] FIG. 7 A illustrates the frame 190 of the example head mounted wearable device 100. The example frame 190 includes the front frame portion 102 defined by a first rim portion 103A/first lens portion 107 A, and a second rim portion 103B/second lens portion 107B, with the bridge portion 109 extending therebetween. A first arm portion 105 A is coupled to the first rim portion 103A by a first hinge mechanism 700A at a first hinge portion 110A. A second arm portion 105B is coupled to the second rim portion 103B by a second hinge mechanism 700B at a second hinge portion HOB. The first hinge mechanism 700 A and the second hinge mechanism 700B may each be dual axis hinge mechanisms that provide for the rotation of the first and second arm portions 105 A, 105B about two axes. In a first mode of operation, the first and second hinge mechanisms 700A, 700B provide for rotation of the first and second arm portions 105A, 105B about a first axis of rotation to, for example, perform an opening and closing movement of the arm portions 105 A, 105B with respect to the front frame portion 102 of the frame 190. In a second mode of operation, the first and second hinge mechanisms 700A, 700B provide for rotation of the first and second arm portions 105 A, 105B about a second axis of rotation to, for example, provide for compliance in response to deflection of the first arm portion 105 A and/or the second arm portion 105B, such that torque loads experienced at the arm portions 105A, 105B are not transferred to the front frame portion 102 of the frame 190. The dual axis nature of the first and second hinge mechanisms 700 A, 700B provides torque control features that absorb or re-direct loads generated due to deflection of the first and/or second arm portions 105 A, 105B, so that those loads are not transferred to the front frame portion 102 and cause twisting or bending of the front frame portion 102, while also providing for the pivoting, or rotation, of the arm portions 105 A, 105B with respect to the front frame portion 102 in the opening and closing of the frame 190.

[0054] FIGs. 7B and 7C are schematic, side views, of a portion of the example head mounted wearable device 100 including the first and second hinge mechanisms 700 A, 700B. In some examples, a configuration of the first hinge mechanism 700A at the first hinge portion 110A is substantially the same as a configuration of the second hinge mechanism 700B at the second hinge portion 110B of the frame 190. Thus, the first and second hinge mechanisms 700 A, 700B may, at times hereinafter be referred to as the hinge mechanism 700, simply for purposes of discussion and illustration.

[0055] FIG. 7B is a first side view, and FIG. 7C is a second side view, of the example frame 190 shown in FIG. 7A. In FIGs. 7B and 7C, the frame 190 is in an open position, for example, a fully open position, in which the first and second arm portions 105 A, 105B have been rotated away from the front frame portion 102 of the frame 190, for example, about an axis Y (i.e., an axis YA and an axis YB), so that the frame 190 can be positioned on the head of a user. In this example, the hinge mechanism 700 includes a first hinge device 710 that provides for operation in a first mode, in which the arm portions 105 rotate about a first axis Y (i.e., an axis YA and an axis YB) between the open position relative to the front frame portion 102 of the frame 190 shown in FIGs. 7A-7C, and the closed position of the arm portions 105 against the front frame portion 102 of the frame 190. The example hinge mechanism 700 includes a second hinge device 720 that provides for operation in a second mode, in which the arm portions 105 rotate about a second axis X (i.e., and axis XA and an axis XB). The operation of the second hinge device 720 of the hinge mechanism 700, and rotation of one or both of the arm portions 105 about the respective second axis X may define a torque control feature.

[0056] In the example arrangement illustrated in FIGs. 7A-7C, the first hinge device 710 is provided in a shoulder portion 122 of the front frame portion 102 of the frame 190 (i.e., a first shoulder portion 122A extending from the first rim portion 103 A, and a second shoulder portion 122B extending from the second rim portion 103B). The first hinge device 710 provides for rotation of the arm portions 105 (i .e., the first arm portion 105 A and the second arm portion 105B) with respect to the front frame portion 102. The first hinge device 710 provides for rotation of the arm portions 105 about an axis Y (i.e., an axis YA at the first hinge portion 110A, and an axis YB at the second hinge portion 110B). The axis Y is oriented vertically (in the example orientation shown in FIGs. 7B and 7C), such that rotation of the arm portions 105 about the axis Y moves the arm portions 105 horizontally (in the example orientation shown in FIGs. 7B and 7C).

[0057] In the example arrangement shown in FIGs. 7B and 7C, the second hinge device 720, defining the torque control feature, is coupled between the shoulder portion 122 and the arm portion 105 (i.e., between the first shoulder portion 122A and the first arm portion 105A, and between the second shoulder portion 122B and the second arm portion 105B). The second hinge device 720 provides for relative rotation of the arm portion 105 and the respective shoulder portion 122 of the front frame portion 102 about an axis X (i.e., rotation of the first arm portion 105A relative to the first shoulder portion 122A about an axis XA, and rotation of the second arm portion 105B relative to the second shoulder portion 122B about an axis XB). The axis X is oriented substantially horizontally (in the example orientation shown in FIGs. 7B and 7C), such that rotation of each arm portion 105 relative to the respective shoulder portion 122 of the front frame portion 102 results in a vertical displacement of the arm portion 105. In particular, in this example, the second hinge device 720 of the first hinge mechanism 700A rotatably couples a lower end portion of the first arm portion 105 A and a lower end portion of the first shoulder portion 122A of the front frame portion 102 of the frame 190. Similarly, in this example, the second hinge device 720 of the second hinge mechanism 700B rotatably couples a lower end portion of the second arm portion 105B and a lower end portion of the second shoulder portion 122B of the front frame portion 102 of the frame 190. In this example, the second axis of rotation X (i.e., the axis of rotation XA and the axis of rotation XB) is positioned at a central portion of the respective second hinge device 720, at the respective lower end portions of the shoulder portions 122 and the arm portions 105.

[0058] In FIGs. 7A-7C, the example frame 190 is in an open, at-rest configuration, in which little to no force is imparted on the arm portions 105, and little to no deflection is experienced at the arm portions 105. In this arrangement, a mating surface 715 of the shoulder portion 122 of the front frame portion 102 abuts a mating surface 725 of the corresponding arm portion 105. In some examples, the mating surface 715 of the shoulder portion 122 and the mating surface 725 of the arm portion 105 define a stopping mechanism that restricts rotation, for example, further rotation, of the arm portion 105.

[0059] In this arrangement, a force, for example, a force in the direction of the arrow Fl shown in FIG. 7D, causes deflection of the arm portion 105 in the direction of the arrow DI. In particular, a force applied to the arm portion 105 in the direction of the arrow F l causes the arm portion 105 to rotate about the X axis, moving the mating surface 725 of the arm portion 105 away from the mating surface 715 of the shoulder portion 122 of the front frame portion 102. In this example, the second hinge device 720, and second axis of rotation X, is at corresponding lower end portions of the arm portion 105 and the shoulder portion 122 of the front frame portion 102. Thus, the force applied in the direction of the arrow Fl causes upper end portions of the arm portion and the shoulder portion 122 to separate and rotate about the axis X at the lower end portions of the arm portion 105 and the shoulder portion 122. In the example shown in FIG. 7D, torque loads associated with the force applied to the arm portion 105 and the resulting deflection of the arm portion 105 are not transferred to the front frame portion 102 of the frame 190.

Rather, the rotation of the arm portion 105 relative to the front frame portion 102 facilitated by the second hinge device 720 of the hinge mechanism 700 reduces or substantially eliminates the transfer of the resulting torque loads from the arm portion 105 to the front frame portion 102 of the frame 190. Thus, the second hinge device 720 of the example hinge mechanism 700 defines a torque control feature of the hinge mechanism 700 that reduces or substantially eliminates the transfer of loads from the arm portion 105 to the front frame portion 102, thus reducing or substantially eliminating any resulting twisting or bending of the front frame portion 102 of the frame 190 due to the deflection of the arm portion 105.

[0060] In this arrangement, the arm portion 105 is restricted from rotating about the axis X in response to a force applied to the arm portion 105 in the direction of the arrow F2 shown in FIG. 7E. That is, the abutting mating surfaces 715, 725 of the shoulder portion 122 and the arm portion 105 define a stopping mechanism. This stopping mechanism may restrict rotation of the arm portion 105 about the axis X beyond the at-rest, aligned position of the arm portion 105 and the shoulder portion 122 of the front frame portion 102 of the frame 190. Thus, further rotation of the arm portion 105 in the direction of the arrow F2, and movement of the arm portion 105 in the direction of the arrow D2 (i.e., upward vertical movement in the example orientation shown in FIG. 7E) relative to the shoulder portion 122, beyond the aligned, at-rest position, is restricted by the stopping mechanism defined by the abutting mating surfaces 715, 725.

[0061] As described above, the dual axis hinge mechanism 700 allows for vertical deflection of the arm portion 105 at the hinge mechanism 700, and in particular, at the second hinge device 720 defining the torque control feature. In particular, the dual axis hinge mechanism 700 allows for deflection of the arm portion 105 in a first vertical direction. As also described above, the dual axis hinge mechanism 700 may restrict (further) rotation, and deflection of the arm portion 105 in a second vertical direction. In some examples, rotation of the arm portion 105 in the direction of the arrow Fl (and resulting deflection in the direction DI) may be substantially unconstrained, while rotation of the arm portion 105 in the direction of the arrow F2 (and resulting deflection in the direction DI) is restricted or limited. In some examples, action of the first hinge mechanism 700A at the first hinge portion 110A of the frame 190 may be axisymmetric from the action of the second hinge mechanism 700B at the second hinge portion HOB of the frame 190.

[0062] FIG. 8A is a first side view, and FIG. 8B is a second side view, of the example frame 190, in a condition in which one of the arm portions 105, and in this particular example, the first ami portion 105 A, experiences deflection from the at-rest position shown in FIGs. 7A- 7C. The deflection of the first arm portion 105 A may be caused by, for example, a relative position of the ear(s) and/or nose of the user, positioning of one or both of the arm portions 105 on the ear of the user, a head width of the user, and the like. In the example shown in FIGs. 8A and 8B, a deflection force is exerted on the first arm portion 105A. This deflection force causes rotation of the first arm portion 105 A, about the axis XA, in the direction of the arrow Fl, facilitated by the second hinge device 720 of the first hinge mechanism 700A in the first hinge portion 110A of the frame 190. The deflection force and rotation of the first arm portion 105 A about the axis XA causes a vertical displacement, i.e., a downward vertical displacement, of the first arm portion 105 A in the direction of the arrow DI, as shown in FIG. 8A. In this example, the second arm portion 105B remains in a fixed position, i.e., at the original, at-rest position. In the original, at-rest position, the mating surface 715 of the second shoulder portion 122B abuts the mating surface 725 of the second arm portion 105B, such that the abutting mating surfaces 715, 725 define a stopping mechanism that restricts (further) rotation of the second arm portion 105B. In this example, the action of the second arm portion 105B is somewhat asymmetric to the action of the first arm portion 105 A in response to the deflection force exerted on the first arm portion 105 A. The loads, for example, torque loads, associated with the deflection of the first arm portion 105 A are not transferred into the front frame portion 102 of the frame 190, but rather, absorbed or dissipated due to the rotation of the first arm portion 105A about the axis XA. Accordingly, the front frame portion 102 of the frame 190 experiences little to no bending or twisting due to the deflection of the first arm portion 105 A, and the front frame portion 102 remains in its original, undeformed state.

[0063] FIG. 9A is a first side view, and FIG. 9B is a second side view, of the example frame 190, in a condition in which one of the arm portions 105, and in this particular example, the first arm portion 105 A, experiences deflection from the at-rest position shown in FIGs. 7A- 7C. In the example shown in FIGs. 9A and 9B, a deflection force is applied to the first arm portion 105A. In this example, the deflection force is an upward force applied to the first arm portion 105A, in the direction of the arrow F2, corresponding to a rotation of the first arm portion in the direction of the arrow F2, and a vertical displacement of the first arm portion 105 A in the direction of the arrow D2. In this example, rotation of the first arm portion 105A in the direction of the arrow F2 relative to the first shoulder portion 122A, about the axis XA, is restricted, or limited, due to the abutting mating surfaces 715, 725 of the first shoulder portion 122A and the first arm portion 105A defining a stopping mechanism. Instead, this deflection force in the direction of the arrow F2 causes a tilting of the front frame portion 102 of the frame 190, as shown in FIGs. 9 A and 9B.

[0064] In response to the tilting of the front frame portion 102 of the frame 190, the second shoulder portion 122B of the frame rotates, about the axis XB, relative to the second arm portion 105B, as shown in FIG. 9B. Relative rotation of the second arm portion 105B and the second shoulder portion 122B in this manner provides for compliance in response to the deflection force applied at the first arm portion 105 A. In this example, the action of the second arm portion 105B is somewhat asymmetric to the action of the first arm portion 105 A in response to the deflection force applied to the first arm portion 105 A. Thus, in this example, loads, for example torque loads, are not transferred from either the first arm portion 105 A or the second arm portion 105B to the front frame portion 102 of the frame 190, and the front frame portion 102 does not experience twisting or bending which would otherwise produce misalignment of display content. In this example, the front frame portion 102 of the frame 190 may experience some slight tilting, but the first rim portion 103A/first lens portion 107A and the second rim portion 103B/second lens portion 107B maintain their relative positions, with the front frame portion 102 in its original, undeformed state, to thus maintain display integrity.

[0065] In the examples described above with respect to FIGs. 8A-8B, and 9A-9B, the mirrored deflection profiles of the first arm portion 105 A and the second arm portion 105B produce an axisymmetric response, and axisymmetric movement of the first arm portion 105 A and the second arm portion 105B in response to a deflection force exerted on one of the arm portions 105. This axisymmetric action of the first arm portion 105A and the second arm portion 105B is enabled by the example dual axis hinge mechanism 700 coupling each of the arm portions 105 to a respective end of the front frame portion 102 of the example frame 190. The ability of the arm portions 105 to rotate about a first axis (for example, a vertical axis) and a second axis (for example, a horizontal axis) provide for compliance in two dimensions, and allow loads, for example torque loads, generated due to deflection forces exerted at the arm portions 105 to be dissipated or absorbed, and not transferred into the front frame portion 102 of the frame 190. This, in turn, maintains display alignment, and integrity of the display content output by the display device 104, particularly in a binocular display arrangement.

[0066] The example implementations described above illustrate various different hinge mechanisms including torque limiting features, or torque control features, in accordance with implementations described herein, which may provide for rotatable coupling of a rim portion 103/front frame portion 102 and an arm portion 105 of a frame 190 of a head mounted wearable device 100 including display capability and/or processing/computing capability. The principles described above can be similarly applied to the rotatable coupling of the rim portion/front frame portion and the arm portions of other types of ophthalmic eyewear.

[0067] Specific structural and functional details disclosed herein are merely representative for purposes of describing example implementations. Example implementations, however, may be implemented in many alternate forms and should not be construed as limited to only the implementations set forth herein.

[0068] The terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting of the implementations. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including," when used in this specification, specify the presence of the stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

[0069] It will be understood that when an element is referred to as being "coupled," "connected," or "responsive" to, or "on," another element, it can be directly coupled, connected, or responsive to, or on, the other element, or intervening elements may also be present. In contrast, when an element is referred to as being "directly coupled," "directly connected," or "directly responsive" to, or "directly on," another element, there are no intervening elements present. As used herein the term "and/or" includes any and all combinations of one or more of the associated listed items.

[0070] Spatially relative terms, such as "beneath," "below," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature in relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the term "below" can encompass both an orientation of above and below. The device may be otherwise oriented and the spatially relative descriptors used herein may be interpreted accordingly.

[0071] Example implementations of the concepts are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized implementations (and intermediate structures) of example implementations. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example implementations of the described concepts should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. Accordingly, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example implementations.

[0072] It will be understood that although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a "first" element could be termed a "second" element without departing from the teachings of the present implementations. [0073] Unless otherwise defined, the terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these concepts belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0074] While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover such modifications and changes as fall within the scope of the implementations. It should be understood that they have been presented by way of example only, not limitation, and various changes in form and details may be made. Any portion of the apparatus and/or methods described herein may be combined in any combination, except mutually exclusive combinations. The implementations described herein can include various combinations and/or subcombinations of the functions, components, and/or features of the different implementations described.