Head-mounted display adjustable to accommodate different head and face sizes

Abstract

To provide a head-mounted display (HMD) adjustable to accommodate different head sizes, face shapes, and eye spacings.SOLUTION: An HMD includes an interpupillary distance (IPD) adjustment mechanism that includes a double biasing assembly for smooth, controlled adjustment of the spacing between lens tubes. The HMD includes a field of view (FOV) adjustment mechanism that includes first and second gear assemblies connected via a connecting rod to allow uniform adjustment of the spacing between lenses and a user's face. The HMD includes a swappable face gasket, a swappable visor, a removable head strap, and a modular accessory compartment for further customizations to the HMD.SELECTED DRAWING: Figure 5A

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a PCT application claiming priority to U.S. Patent Application No. 16 / 850,426, filed April 16, 2020, which claims priority to U.S. Provisional Patent Application No. 62 / 837,662, filed April 23, 2019. Applications Nos. 16 / 850,426 and 62 / 837,662 are incorporated herein by reference in their entireties. [Technical Field]

[0002] [Background technology] Head-mounted displays are used in a variety of fields, including engineering, medicine, the military, and video games. In some cases, head-mounted displays may present information or images to a user as part of a virtual reality or augmented reality environment. As an example, a user may wear a head-mounted display while playing a video game to immerse the user in a virtual environment.

[0003] Conventional head-mounted displays have insufficient or no adjustment to accommodate different head sizes, face shapes, and eye spacing. As a result, some users may find it difficult to wear a head-mounted display comfortably. For example, if the lens barrel is horizontally misaligned with the user's eyes, the scene presented on the head-mounted display may be only partially visible to the user. If the display panel is too close or too far from the user's eyes, the user's field of view (FOV) may not be optimized. Therefore, conventional head-mounted displays may not be able to adapt to different users. Adjustable head-mounted displays tend to be difficult and / or inconvenient to adjust due to crude adjustment mechanisms, which do not provide an optimal level of comfort and frustrate users. [Brief explanation of the drawings]

[0004] The detailed description will now be described with reference to the accompanying drawings, in which the leftmost digit(s) of a reference number identifies the figure in which the reference number first appears. The same or similar reference numbers in different figures indicate similar or identical items.

[0005] [Figure 1] 1 illustrates a front perspective view of an exemplary head-mounted display (HMD) with the visor shown exploded from the HMD to reveal a modular accessory compartment, according to one embodiment of the present disclosure.

[0006] [Figure 2] 2 illustrates a front perspective view of the front portion of the HMD of FIG. 1 according to one embodiment of the present disclosure.

[0007] [Figure 3A] 2 illustrates a rear perspective view of the exemplary HMD of FIG. 1 in a configuration in which the head strap of the HMD is attached to the main unit of the HMD, according to one embodiment of the disclosure.

[0008] [Figure 3B] 3A illustrates an exemplary HMD in a configuration in which the head strap is detached from the HMD.

[0009] [Figure 4] 2 illustrates a rear perspective view of the main unit of the exemplary HMD of FIG. 1 with the face gasket disconnected from the main unit, according to one embodiment of the present disclosure.

[0010] [Figure 5A] 5A illustrates a partial front and bottom view of the exemplary HMD of FIG. 1 with a front portion of the HMD housing removed to reveal components of the interpupillary distance (IPD) adjustment mechanism, and with the IPD adjustment mechanism adjusted to a first end of its adjustment range, according to one embodiment of the present disclosure.

[0011] [Figure 5B]5A illustrates the exemplary HMD shown in FIG. 5A, but with the IPD adjustment mechanism adjusted to the second end of the adjustment range in FIG. 5B.

[0012] [Figure 6A] 6A illustrates a partial rear and bottom view of the exemplary HMD of FIG. 1 with the lens barrels spaced apart by the maximum distance of the IPD adjustment range of FIG. 6A, according to one embodiment of the present disclosure.

[0013] [Figure 6B] 6A illustrates an exemplary HMD, with the lens barrels spaced apart by the minimum distance of the IPD adjustment range in FIG. 6B.

[0014] [Figure 7A] 7A illustrates a partial front perspective view of the exemplary HMD of FIG. 1 with a portion of the HMD housing removed to reveal components of the field of view (FOV) adjustment mechanism, with the FOV adjustment mechanism adjusted to a first end of its adjustment range, according to one embodiment of the present disclosure.

[0015] [Figure 7B] 7A illustrates the exemplary HMD shown in FIG. 7A, but with the FOV adjustment mechanism adjusted to the second end of the adjustment range in FIG. 7B.

[0016] [Figure 8] 8 illustrates a front perspective view of the exemplary HMD of FIG. 1, and illustrates an exemplary location of a discreet spectrally transmissive window within the housing of the HMD, according to one embodiment of the disclosure.

[0017] [Figure 9] 1 is a flowchart of an exemplary process for manufacturing a housing of an HMD having at least one spectrally transmissive window, according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0018] As described above, head-mounted displays (HMDs) have a wide range of applications and may need to accommodate various head sizes, face shapes, and eye spacing among different users. However, conventional HMDs offer little or no adjustment to accommodate different users. For example, in conventional HMDs, the distance between the lens barrels may be fixed, or if adjustable, the adjustment mechanism may be difficult or inconvenient to operate, especially while wearing the HMD. In conventional HMDs, the distance between the user's face and the display panel (or lenses) may be fixed, or if adjustable, the adjustment mechanism may be difficult or inconvenient to operate, especially while wearing the HMD.

[0019] This specification describes, among other things, techniques and systems, including HMDs, for adjusting the spacing between a pair of lens barrels of the HMD to accommodate users with various interpupillary distances (IPDs). For example, the HMD may include a rod connected to an intermediate frame of the HMD and a pair of lens barrels connected to the rod (e.g., via a pair of movable frames connected to the pair of lens barrels), with each lens barrel / movable frame movable along the rod in both directions (e.g., in a first direction toward the left side of the HMD or a second direction toward the right side of the HMD). The HMD may also include an actuator accessible from outside the housing of the HMD, and a movable elongated member connected to the actuator and the intermediate frame. A first biasing member connected to the movable elongated member and the intermediate frame is configured to resist movement of the movable elongated member in the direction of travel of the elongated member. A rotatable gear coupled to the intermediate frame and disposed between the pair of lens barrels / movable frames engages the movable elongated member, and a pair of second biasing members coupled to the rod are configured to physically bias the pair of lens barrels / movable frames toward the rotatable gear (e.g., by physically biasing the pair of movable frames against a pair of helical protrusions extending from the faces of the rotatable gear).

[0020] Also described herein are, among other things, technologies and systems, including HMDs, for adjusting the distance between a user's face and the lenses of the HMD to adjust the field of view (FOV) and / or eye relief to accommodate different users. For example, the HMD may include a pair of lens assemblies coupled to a first portion of the HMD. An actuator disposed on a first side of the HMD may be accessible from outside the housing of the HMD, and a pair of gear assemblies disposed on an opposite side of the HMD may be coupled to a second portion of the HMD connected by a connecting rod and movable relative to the first portion of the HMD. One of the gear assemblies is disposed on the first side and coupled to the actuator, such that actuation of the actuator causes the pair of gear assemblies to move the second portion of the HMD relative to the first portion of the HMD.

[0021] Also described herein are, among other things, electronic devices (e.g., HMDs) having a housing made of a spectrally transparent material configured to allow a specific spectrum of electromagnetic radiation to pass therethrough. An exterior surface of the housing may be coated with a spectrally non-transparent material configured to block a specific spectrum of electromagnetic radiation, and one or more locations on the exterior surface are devoid of the spectrally non-transparent material to provide one or more spectrally transparent windows on the housing. One or more spectrally specific components (e.g., sensors, beacons, etc.) may be disposed inside the housing behind the one or more spectrally transparent windows.

[0022] A process for manufacturing an electronic device (e.g., an HMD) having at least one window that allows a specific spectrum of electromagnetic radiation to pass through the at least one window may include forming a housing for the electronic device from a first material configured to allow a specific spectrum of electromagnetic radiation to pass therethrough, painting an exterior surface of the housing with a second material configured to block the specific spectrum of electromagnetic radiation, and removing the second material from at least one location on the exterior surface to create the at least one window. In some embodiments, the specific spectrum is the IR spectrum.

[0023] The present disclosure provides a general understanding of the principles of structure, function, manufacture, and use of the systems and methods disclosed herein. One or more examples of the present disclosure are illustrated in the accompanying drawings. Those skilled in the art will understand that the systems and methods specifically described herein and illustrated in the accompanying drawings are non-limiting embodiments. Features illustrated or described in connection with one embodiment, including between systems and methods, can be combined with features of other embodiments. Such modifications and variations are intended to be within the scope of the appended claims.

[0024] FIG. 1 illustrates a front perspective view of an exemplary head-mounted display (HMD) 100 (sometimes referred to herein as a “wearable display,” “VR headset,” “AR headset,” or “headset”), with a visor 106 shown exploded from the HMD 100 to reveal a modular accessory compartment 102. The HMD 100 may include a front portion (or main unit) positioned in front of or above a user's eyes to render images output by an application (e.g., a video game). In some cases, the application may run on a computing device (e.g., a personal computer (PC), game console, etc.) associated with and / or communicatively coupled to the HMD 100. In some cases, the HMD 100 may not rely on an external computing device and may execute applications and render corresponding images using onboard components (e.g., logic, hardware, memory, processor (e.g., central processing unit (CPU), graphics processing unit (GPU), etc.), battery, etc.). The HMD 100 may be configured to output a series of images (frames) that are viewed by a user through an optical system within the HMD 100, causing the user to perceive the images as if immersed in a virtual reality (VR) or augmented reality (AR) environment.

[0025] The HMD 100 may include a visor 106 that is replaceable or interchangeable with other types of visors. The visor 106 may be of a customized shape, and the visor 106 may include customized materials and / or customized artwork (e.g., coloring, stickers, markings, holes, surface features, etc.). A user can interchange the visor 106 with a different visor to change the appearance or appearance of the HMD 100 on the front of the HMD 100. Different users who use the HMD 100 may have their own customized visor 106, which allows the user to remove the existing visor 106 and replace it with their own customized visor. The visor 106 may be removably attached to the front of the HMD 100 in any suitable manner, such as by a magnetic coupling mechanism (e.g., a magnet on the front of the HMD 100 that couples to a corresponding magnet on the visor 106), a hook-and-loop fastener (e.g., Velcro®), a pin, a screw, a hook, a snap / press-fit mechanism, an adhesive, or any suitable type of fastener.

[0026] When attached to the HMD 100, the visor 106 may cover the compartment 102 (sometimes referred to herein as the “modular accessor compartment 102”). The compartment 102 may be of any suitable shape. FIG. 1 illustrates a rectangular compartment 102 that is recessed a distance in front of the HMD 100. The compartment 102 may include a port 104, such as a universal serial bus (USB) port 104, that is electrically connected to components on a printed circuit board (PCB) within the housing of the HMD 100. The port 104 may allow a user to connect modular accessories to the HMD 100 to provide further customization to the user of the HMD 100. For example, a light(s) (e.g., a light-emitting diode (LED)) may be connected to the port 104, which may provide power to the light to turn it on. These lights may be disposed within the compartment 102 behind the visor 106, which may be made of an optically transparent material (e.g., clear or colored plastic) to provide customized lighting effects for the HMD 100. The visor 106 may be any suitable color, and when the visor 106 covers the lights within the compartment 106 connected via the port 104, the visor 106 may be illuminated to provide a customized visual appearance. In some embodiments, a display (e.g., a liquid crystal display (LCD)) may be connected to the port 104 and disposed within the compartment 102 to render images on the display while the HMD 100 is worn by a user. In other scenarios, auxiliary camera(s) may be connected to the port 104 and disposed within the compartment 102. In some embodiments, auxiliary and / or backup computer processing resources (e.g., processing, storage, power, etc.) may be connected via the port 104 to augment the processing power, storage capacity, and / or battery life of the HMD 100.

[0027] FIG. 2 illustrates a front perspective view of the front portion of HMD 100 of FIG. 1 , according to one embodiment of the present disclosure. As shown in FIG. 2 , HMD 100 may include one or more forward-facing cameras 200(1) and / or 200(2). While FIG. 2 illustrates an embodiment with two forward-facing cameras 200, including first camera 200(1) and second camera 200(2), any suitable number of forward-facing cameras 200 may be utilized. The forward-facing cameras 200 may be used for any suitable purpose, such as optical tracking, pass-through imaging (e.g., projecting an image of the real-world environment onto HMD 100, such as by projecting a real-world image on top of a VR scene), obstacle detection (e.g., detecting objects in the real-world environment and possibly alerting the user of a potential collision with such objects), recording video of the environment during gameplay, etc. The forward-facing camera 200 may be located in any suitable location on the HMD 100, such as on the front of the HMD 100 towards the bottom of the HMD 100 (e.g., the bottom half of the HMD 100), as shown in FIG.

[0028] FIG. 3A illustrates a rear perspective view of the example HMD 100 of FIG. 1 in a configuration in which the head strap 300 of the HMD 100 is attached to the main unit 302 of the HMD 100, according to one embodiment of the disclosure. FIG. 3B illustrates the example HMD 100 shown in FIG. 3A, except in a configuration in which the head strap 300 is detached from the main unit 302 of the HMD 100. The head strap 300 may be removed to replace or interchange the head strap 300 with a different head strap 300. Extended use of the HMD 100 may cause the material of certain portions of the head strap 300 to absorb body odor, and as a result, a user may wish to remove the head strap 300 from time to time to "air out" the head strap 300, clean the head strap 300, replace the head strap 300 with a new head strap, etc. In some cases, a user may desire to interchange or replace head strap 300 with a different type of head strap (e.g., one having different features such as different headphones, different adjustment mechanisms, etc.), which provides further customization of HMD 100 for different users.

[0029] 3B, head strap 300 can be removed by removing actuator 304 (e.g., a rotatable knob) located on the side of HMD 100 to access one or more screws 310(1) or similar fasteners. Removal of actuator 304 can be achieved in any suitable manner, such as by forcibly pulling actuator 304 outward to remove it from mounting pin 308(1). Mounting pin 308(1) can be inserted through a main opening in a portion of head strap 300, while one or more screws 310(1) can be threaded into one or more corresponding openings 306(1) in a portion of head strap 300 to secure head strap 300 to main unit 302. A user can unscrew screw(s) 310(1) and then slide a portion of head strap 300 off mounting pin 308(1) to remove one side of head strap 300 from the corresponding side of main unit 302. On the opposite side of main unit 302, there may be one or more screws (e.g., similar to screw 310(1)) threaded into one or more corresponding openings 306(2) in another portion of head strap 300 to secure head strap 300 to main unit 302 on the opposite side of main unit 302. A user can unscrew these screws from the opposite side of main unit 302 to remove the other side of head strap 300, and thus the entire head strap 300, from main unit 302. 3B also shows a belt loop 312 on the top of the main unit 302 of the HMD 100, which is configured to receive the top member of the head strap 300 by looping the top member through the belt loop 312 and securing the top member of the head strap 300 to the belt loop 312 itself. The fastening mechanism for the top member of the head strap 300 may be any suitable mechanism, such as a hook-and-loop fastener (e.g., Velcro®), a snap, or the like. In this manner, the head strap 300 is removable and can be reattached at will by the user.

[0030] 4 illustrates a rear perspective view of the main unit 302 of the exemplary HMD 100 of FIG. 1 with a face gasket 400 detached from the main unit 302, according to one embodiment of the present disclosure. The face gasket 400 may be removably attached to the main unit 302 of the HMD 100 in any suitable manner, such as by a magnetic coupling mechanism, hook-and-loop fastener(s) (e.g., Velcro®), pins, screws, hooks, a snap / press-fit mechanism, adhesive, or any suitable type of fastener. FIG. 4 illustrates one embodiment in which the face gasket 400 is removably coupled to the main unit 302 using a magnetic coupling mechanism(s). For example, a plurality of first magnetic elements 402(1)-(4) (e.g., metal screws) disposed on the rear of the main unit 302 may couple with a plurality of second magnetic elements 404(1)-(4) (404(1) and 404(2) are not shown in FIG. 4 ) disposed on the front of the face gasket 400. In this manner, the face gasket 400 may be easily and conveniently fixed to the rear of the main unit 302 or detached from the rear of the body unit 302. The face gasket 400 may be padded on the rear to provide a comfortable fit when the HMD 100 is worn. As mentioned above, long-term use of the HMD 100 may result in the materials of certain components, such as the face gasket 400, absorbing body odor. As a result, a user may desire to remove face gasket 400 from time to time to "air out" face gasket 400, clean face gasket 400, replace face gasket 400 with a new face gasket, etc. In some embodiments, a user may desire to interchange or replace face gasket 400 with a different type of face gasket (e.g., one having different features, profiles, contours, etc.), thereby allowing for even further customization of HMD 100 for different users.

[0031] 5A illustrates partial front and bottom views of the exemplary HMD 100 of FIG. 1 , with a front portion of the HMD housing removed to reveal components of an interpupillary distance (IPD) adjustment mechanism, with the IPD adjustment mechanism adjusted to a first end of its adjustment range in FIG. 5A and to a second end of its adjustment range in FIG. 5B , in accordance with one embodiment of the present disclosure. The IPD adjustment mechanism of HMD 100 allows adjustment of the horizontal spacing between a pair of lens barrels of HMD 100. FIGS. 6A and 6B illustrate exemplary lens barrels 600(1) and 600(2) (sometimes referred to herein as “lens assemblies”) that can be moved closer together or farther apart using the IPD adjustment mechanism to decrease or increase the horizontal spacing between the lens barrels, respectively. In particular, the IPD adjustment mechanism described herein is convenient to operate while wearing HMD 100, can be operated using a single hand or finger, and includes a dual biasing assembly to provide smooth, controlled operation of the IPD adjustment mechanism throughout its adjustment range, allowing fine adjustment of the distance between lens barrels 600(1) and 600(2) to accommodate the user's IPD, among other things.

[0032] As shown in FIGS. 5A and 5B , the IPD adjustment mechanism may include an actuator 500. The actuator 500 may be located on (or within) the bottom of the HMD 100 toward the right or left half of the HMD 100. While the actuator 500 may be implemented in any suitable manner (e.g., a rotatable knob, a lever, a depressible button that toggles between adjustment positions, etc.), the actuator 500 shown in FIGS. 5A and 5B includes a knob that is slidable (or otherwise movable) within a channel 502 defined in the housing of the HMD 100. The actuator 500 is configured to be actuated by a user of the HMD 100 to adjust the spacing between lens barrels 600(1) and 600(2) (as illustrated in FIGS. 6A and 6B ). Thus, the actuator 500 is accessible from outside the housing of the HMD 100. 5A and 5B, moving the actuator 500 to a first end of the channel 502 (e.g., as shown in FIG. 5A) maximizes the horizontal distance (or spacing) between the pair of lens barrels 600 of the HMD 100. Moving the actuator 500 to a second end of the channel 502 opposite the first end of the channel 502 (e.g., as shown in FIG. 5B) minimizes the horizontal distance (or spacing) between the pair of lens barrels 600 of the HMD 100. In this manner, a user with a smaller IPD can adjust the knob toward the second end of the channel 502 (as shown in FIG. 5B), while a user with a larger IPD can adjust the knob toward the first end of the channel 502 (as shown in FIG. 5A). Markings can be provided on the exterior surface of the HMD housing along the channel 502 to indicate to the user that the horizontal spacing between the lens barrels 600 is adjustable. The actuator 500 and channel 502 are located on either the right or left half of the HMD 100, so that on the bottom of the HMD 100, a user can easily and conveniently slide the actuator 500 within the channel 502 using their right or left thumb (e.g., a single hand) to adjust the spacing between the lens barrels 600.The location of the actuator 500 and the channel 502, along with the ease of operation of the actuator 500 and the channel 502, allow a user to adjust the spacing of the lens barrels 600 with a single hand and to do so while wearing the HMD 100, such that the user does not have to take off the HMD 100 or hold the HMD 100 with two hands while adjusting the spacing of the lens barrels 600. This allows a user to more quickly achieve optimal spacing of the lens barrels 600, since they can wear the HMD 100 while adjusting the spacing of the lens barrels 600 and determine in real time which position of the actuator 500 is optimal for them.

[0033] The IPD adjustment mechanism may include components inside the housing of the HMD 100 that enable smooth and effortless operation of the IPD adjustment mechanism. For example, an end of an actuator 500, inside the HMD housing, may be coupled to a movable elongated member 504 at a first end of the elongated member 504. As shown in FIGS. 5A and 5B , the elongated member 504 may be oriented horizontally and adjacent the bottom of the HMD 100. However, it should be understood that other orientations of the elongated member 504 are possible. A channel or slot may be defined in the elongated member 504 adjacent the end of the elongated member 504 coupled to the actuator 500, and an anchor 506 attached to the mid-frame of the HMD 100 may extend through the channel / slot of the elongated member 504 to enable the elongated member 504 to translate bidirectionally (e.g., in a first or second horizontal direction when the HMD 100 is oriented upright) throughout the adjustment range of the IPD adjustment mechanism. In this manner, the elongated member 504 is connected to the intermediate frame of the HMD 100 but is movable in both directions.

[0034] A first end of the first biasing member 508 may be coupled to a first end of the elongated member 504, and a second end of the first biasing member 508 may be coupled to an intermediate frame of the HMD 100. Here, the first end of the elongated member 504 (coupled to the first biasing member 508) is farthest from the actuator 500, while the second end of the elongated member 504 is closest to the actuator 500. The second end of the first biasing member 508 may be attached to the intermediate frame of the HMD 100 at a point closer to the actuator 500 than the first end of the elongated member 504 is relative to the actuator 500. In this manner, the first biasing member 508 is configured to physically bias the elongated member 504 in the horizontal direction by applying a biasing force to the elongated member 504 that resists movement of the elongated member 504 in the direction of travel of the elongated member 504. In the example of Figures 5A and 5B, as the actuator 500 moves from the left end of the channel 502 to the right end of the channel 502 (from the perspective of Figures 5A and 5B), the elongated member 504 translates in a rightward direction of travel, and the first biasing member 508 resists the rightward movement of the elongated member 504 due to a biasing force applied to the elongated member 504 in the leftward direction. In some embodiments, the first biasing member 508 is a spring, and the biasing force of the spring against the elongated member 504 increases as the elongated member 504 moves further and further in the rightward horizontal direction (from the perspective of Figures 5A and 5B). This biasing force from the first biasing member 508 provides a smooth, rather than jerky, sliding motion of the actuator 500 within the channel 502 when a user slides the actuator 500 within the channel 502. Additionally or alternatively, one or more friction members may help resist movement of the actuator 500 within the channel 502, making the movement smoother and more controlled and making it easier to fine-tune the IPD adjustment.

[0035] The elongated member 504 may include a plurality of teeth spanning at least a portion of the elongated member 504 on a top side thereof. The teeth of the elongated member 504 engage with teeth of a rotatable gear 510 (sometimes referred to herein as a “helical gear”) mounted on a shaft on the mid-frame of the HMD 100. The gear 510 may be disposed between a pair of movable frames 516(1) and 516(2) connected to a pair of lens barrels 600 at or near the center of the HMD 100. The gear 510 may include a face having a pair of helical protrusions 512(1) and 512(2) extending from the face of the gear 510. A rod 514 (sometimes referred to herein as a “sliding rod”) may be connected to the mid-frame of the HMD 100. The sliding rod 514 may be oriented horizontally (when the HMD 100 is oriented upright) and may span substantially the width of the HMD 100. As described above, each lens barrel 600 of the pair of lens barrels 600 may be coupled to a corresponding movable frame 516 within the HMD housing, and each movable frame 516 may include a wing member 518 that protrudes from the underside of the movable frame 516 coupled to the sliding rod 514 (e.g., by the sliding rod 514 passing through an opening in the wing member 518). In this manner, the pair of lens barrels 600 may be coupled to the rod 514 via the movable frame 516. As shown in FIG. 5A , each wing member 518 may also include a protrusion 519 that extends horizontally from the wing member 518 toward the gear 510. A protrusion 519 extending from wing member 518 engages one of helical protrusions 512 extending from the face of gear 510. For example, a first protrusion 519(1) may extend from wing member 518(1) and engage with helical protrusion 512(1), while a second protrusion 519(2) may extend from wing member 518(2) and engage with helical protrusion 512(2).

[0036] A pair of second biasing members 520(1) and 520(2) may be coupled to slide rod 514. For example, second biasing member 520 may comprise a spring mounted on slide rod 514 and positioned between a stop 522 on slide rod 514 and a wing member 518 of each movable frame 516. Figures 5A and 5B show first stop 522(1) and second biasing member 520(1) between first stop 522(1) and wing member 518(1), as well as second stop 522(2) and second biasing member 520(2) between second stop 522(2) and wing member 518(2). Each of the second biasing members 520 may be fixed in position relative to the sliding rod 514 at one end of the second biasing member 520 (e.g., a stop 522 on the sliding rod 514), and the second biasing member 520 may apply a biasing force to a corresponding wing member 518 coupled to the sliding rod 514, the biasing force being applied in a direction toward the gear 510 such that a protrusion 519 extending horizontally from the wing member 518 is physically biased against a corresponding helical protrusion 512 extending from the face of the gear 510. Because the movable frame 516 is movable bidirectionally along the rod 514 between the left and right sides of the HMD 100, the movable frame 516, and therefore the lens barrel 600 coupled to the movable frame 516, moves in response to actuation of the actuator 500.

[0037] As shown in FIGS. 5A and 5B , a user can slide IPD adjustment mechanism actuator 500 within channel 502, thereby translating elongated member 504 in a first direction (e.g., rightward from the perspective of FIGS. 5A and 5B ). Teeth of elongated member 504 engaging teeth of gear 510 causes gear 510 to rotate. In the first rotational direction of gear 510, helical protrusion 512 extending from the face of gear 510 exerts a force on protrusions 519 extending from wing members 518 of movable frame 516, causing movable frame 516 (and thus lens barrels 600) to move farther apart, increasing the spacing between lens barrels 600 (as shown in FIG. 5A ). In a second rotational direction of gear 510, the pair of second biasing members 520 exert a biasing force on wing members 518 of movable frame 516, causing movable frame 516 (and thus lens barrels 600) to move closer together, decreasing the spacing between lens barrels 600 (as shown in FIG. 5B ). This is due in part to helical protrusions 512 on gear 510 spiraling inward from respective points on the circumference of gear 510 to respective points closer to the center of gear 510 than respective points on the circumference.

[0038] In particular, as the movable frames 516 (and thus the lens barrel 600) move farther apart, the pair of second biasing members 520 resists movement of the movable frames 516 in the direction of each movable frame's 516's respective travel. This ensures that when a user slides the actuator 500 within the channel 502, the sliding movement of the actuator 500 within the channel 502 is smooth and controlled, rather than jerky. Thus, the first biasing member 508 and the pair of second biasing members 520 move together to enable smooth and controlled sliding movement of the actuator 500 within the channel 502, allowing the user to easily fine-tune the IPD adjustment, even while wearing the HMD 100. Additionally or alternatively, one or more friction members can help resist movement of the actuator 500 within the channel 502, making the movement smoother and making it easier to fine-tune the IPD adjustment. Opposing biasing and / or friction members allow actuator 500 to move within channel 502 to any position within channel 502 as desired by the user, and when the user removes their finger from actuator 500, actuator 500 remains stationary at its current position within channel 502.

[0039] As illustrated in FIGS. 6A and 6B, actuation of actuator 500 causes a corresponding adjustment of the spacing between lens barrels 600 of HMD 100. For example, as shown in FIG. 6A, moving actuator 500 to a first end of channel 502 maximizes the horizontal distance (spacing) between lens barrel 600(1) and lens barrel 600(2). The lens barrels 600 may be substantially horizontally aligned. As shown in FIG. 6B, moving actuator 500 to a second end of channel 502 minimizes the horizontal distance (spacing) between lens barrel 600(1) and lens barrel 600(2). An intermediate spacing may be achieved by moving actuator 500 to an intermediate position within channel 502. In this sense, the actuator 500 can move in a smooth, continuous motion along the channel 502, as opposed to discrete "clicks" between multiple adjustment positions, and the user will experience bidirectional resistance in either direction that the actuator 500 moves due to the dual biasing assembly described herein.

[0040] FIG. 7A illustrates a partial front perspective view of the exemplary HMD 100 of FIG. 1 , with a portion of the HMD housing removed to reveal components of the field of view (FOV) adjustment mechanism, in FIG. 7A , with the FOV adjustment mechanism adjusted to a first end of its adjustment range. FIG. 7B shows the FOV adjustment mechanism adjusted to a second end of its adjustment range. The FOV adjustment mechanism illustrated in FIGS. 7A and 7B allows adjustment of the distance between the user's face and the lens or lens barrel 600 (or display panel) of the HMD 100. This field of view (FOV) adjustment mechanism (sometimes referred to herein as an “eye relief adjustment mechanism”) is, among other things, convenient to operate while wearing the HMD, can be operated using a single hand, and smoothly adjusts (e.g., increases or decreases) the distance between the lens of the HMD 100 and the user's face over an adjustment range. The FOV adjustment mechanism may include an actuator 304 disposed on a first side (of two sides, i.e., the right and left sides) of the HMD 100. Generally, the actuator 304 is configured to be actuated by a user of the HMD 304, and therefore the actuator 304 is accessible from outside the HMD housing.

[0041] Although the actuator 304 is shown in FIGS. 7A and 7B as a rotatable actuator (e.g., a rotatable knob), the actuator 304 may include any suitable adjustable element, including, but not limited to, a dial, a lever, a wheel, and / or a slider (or slidable knob). The actuator 304 may be located where the head strap 300 is adjacent to the main unit 302 of the HMD 100. The actuator 304 may be actuated (e.g., rotated) through an adjustment range such that actuation (e.g., rotation) in a first direction to a first end of the adjustment range minimizes the distance (or spacing) between the lenses and the user's face, and actuation (e.g., rotation) in a second direction opposite the first direction to a second end of the adjustment range maximizes the distance (or spacing) between the lenses and the user's face. In this manner, the FOV and / or eye relief may be optimized for different users. Markings can be provided on the exterior surface of the HMD housing around or on the actuator 304 to indicate to the user that the spacing between the lenses and the user's face is adjustable. Because the actuator 304 is located on one side (e.g., the right or left side) of the HMD 100, the user can easily and conveniently actuate the actuator 304 using their right or left hand (e.g., a single hand) to adjust the spacing between the lenses and the user's face. The location of the actuator 304, along with the ease of operation of the actuator 304, allows the user to adjust the FOV and / or eye relief with a single hand and to do so while wearing the HMD 100, so that the user does not have to take off the HMD 100 or hold the HMD 100 with two hands while adjusting the FOV and / or eye relief. This allows the user to more quickly achieve the optimal FOV and / or eye relief because they can wear the HMD 100 while adjusting the FOV and / or eye relief and determine in real time which position of the actuator 304 is optimal for them.

[0042] The FOV adjustment mechanism includes components within the housing of the HMD 100 that enable uniform, smooth, controlled, and / or effortless operation of the FOV adjustment mechanism. In addition to being rotatable, the actuator 304 (e.g., a rotatable knob) may be depressible between a first position and a second position by depressing the actuator 304, much like a depressible button. A biasing member may bias the actuator 304 outward relative to the HMD 100 such that, when a user is not depressing the actuator 304, the actuator 304 is physically biased to a first position in which the actuator 304 is extended (i.e., not depressed). When the actuator 304 is extended, a protrusion (or tooth) engages with one of a plurality of detents within the actuator 304, thereby locking the actuator 304 in the sense that it prevents the actuator 304 from rotating in either direction (clockwise or counterclockwise) throughout the adjustment range. A user can move the actuator 304 to a second position in which the actuator 304 is depressed, thereby unlocking the actuator 304 by disengaging the protrusions from the detents inside the actuator 304. In this second position, while depressing the actuator 304, the user can rotate the actuator 304 to adjust the spacing between the lens and the user's face as needed. Upon releasing the actuator 304 or relieving pressure on the actuator 304, a biasing member inside the actuator 304 physically biases the actuator 304 to the extended first position, engaging the protrusions with the detents, thereby locking the actuator 304 in place (rotationally). This locking mechanism prevents undesired adjustment of the spacing between the lens and the user's face, such as during gameplay, when a user wants the FOV and / or eye relief to remain fixed in a desired position.

[0043] The actuator 304 can cause rotation of a pair of gear assemblies on either side of the HMD 100, which are connected by a connecting rod 706. The pair of gear assemblies can adjust the lenses closer to or farther from the user's face. Specifically, the main unit 302 of the HMD 100 can include a first portion coupled to the lens barrel 600 and a second portion movable relative to the first portion. For example, the second portion of the HMD 100 can be a portion of the main unit 302 that is closer to (e.g., in contact with) the user's face while the user is wearing the HMD 100. Referring briefly to FIG. 3B , this second portion 314 is a portion of the main unit 302 on which the actuator 304 is disposed. The first portion 316 of the HMD 100 can be a portion of the main unit 302 that is farther from (e.g., not in contact with) the user's face while the user is wearing the HMD 100. For example, the first portion 316 of the HMD 100 may include, but is not limited to, a lens barrel 600, a display panel, a PCB having electrical components mounted thereon, etc. These first and second portions of the HMD 100 are movable bidirectionally and relative to one another by rotational actuation of the actuator 304.

[0044] A first gear assembly, disposed on the same side of the HMD 100 as the actuator 304, may be coupled to the actuator 304 and to both the first portion 316 of the HMD 100 and the second portion 314 of the HMD 100, which are movable bidirectionally and relative to each other. The first gear assembly may include a first rotatable gear 702(1) having teeth that engage with teeth on the elongated member 700(1). The teeth on the elongated member 700(1) may be disposed on a top side of the elongated member 700(1). The elongated member 700(1) may be oriented such that the elongated member 700(1) extends in a direction from the back of the HMD 100 to the front of the HMD 100. Elongated member 700(1) may be coupled to or engage actuator 304, and elongated member 700(2) may also be coupled to a second portion 314 of HMD 100, which is closer to the user's face than a first portion 316 of HMD 100. Because elongated member 700(1) is coupled to second portion 314 of HMD 100, when actuator 304 rotates, elongated member 700(1) translates forward or backward, causing second portion 314 of HMD 100 (the portion closer to the user's face) to translate forward or backward relative to first portion 316 of HMD 100 (the portion farther from the user's face, including the lenses, display, and PCB).

[0045] The elongated member 700(1) may also include teeth that engage with teeth of a first gear 702(1), which is mounted on a shaft on the mid-frame of the HMD 100. The first gear 702(1) of the first gear assembly engages with a second rotatable gear 704(1) of the first gear assembly, which is coupled to a rod 706 (sometimes referred to herein as a “connecting rod”). The connecting rod 706 may be coupled to the mid-frame of the HMD, which may be oriented horizontally and span substantially the width of the HMD 100. The connecting rod 706 also connects the first gear assembly to a second gear assembly, which is disposed on a second side of the HMD 100 opposite the first side of the HMD 100 on which the first gear assembly is disposed. Rotation of the second gear 704(1) of the first gear assembly causes a corresponding rotation of the connecting rod 706.

[0046] The second gear assembly may include a third rotatable gear coupled to the connecting rod 706, much like the second gear 704(1) of the first gear assembly is connected to the connecting rod 706 at the opposite end of the rod 706. Rotation of the connecting rod 706 causes corresponding rotation of this third gear of the second gear assembly. This third gear of the second gear assembly engages with a fourth rotatable gear of the second gear assembly, which is much like the first gear 702(1) of the first gear assembly. Thus, the fourth gear of the second gear assembly may similarly be mounted on a shaft on the mid-frame of the HMD 100. Teeth of the fourth gear engage with teeth of the second elongated member 700(2) of the second gear assembly. This second elongated member 700(2) may also have teeth on the top side of the elongated member 700(2), and the elongated member 700(2) of the second gear assembly may similarly be attached to the second portion 314 (the portion closer to the user's face) of the HMD 100, which is movable relative to the first portion 316 of the HMD 100 (the portion farther from the user's face, including the lenses, display, and PCB), except that the second elongated member 700(2) is connected to the second portion 314 of the HMD 100 on an opposite side of the second portion 314 compared to the side on which the first elongated member 700(1) is connected to the second portion 314 of the HMD 100.

[0047] Thus, when actuator 304 rotates, both elongated members 700(1) and 700(2) of their respective gear assemblies translate forward or backward, depending on the direction of rotation of actuator 304, thereby causing first and second portions of HMD 100 to translate in opposite directions relative to one another, thereby adjusting the FOV and / or eye relief. For example, first portion 316 of HMD 100 (the portion farther from the user's face, including the lens, display, and PCB) may move relative to second portion 314 of HMD 100 (the portion closer to the user's face) in a first direction away from second portion 314 or in a second direction toward second portion 314. By controlling the movement of these HMD portions using elongated members 700(1) and 700(2) on opposite sides of HMD 100 connected by connecting rod 706, the first and second portions of HMD 100 can translate uniformly relative to one another without any wobble (or racking) of these portions when translating bidirectionally forward or backward. This smooth and uniform adjustment provided by the FOV (or eye relief) adjustment mechanism allows for convenient operation by a user using a single hand while wearing HMD 100.

[0048] FIG. 8 illustrates a front perspective view of the exemplary HMD 100 of FIG. 1 , illustrating exemplary locations of unobtrusive spectrally transmissive windows 800(1)-(N) (collectively 800, where N is any integer) within the housing of the HMD 100, according to one embodiment of the disclosure. In some embodiments, multiple corresponding spectrally specific sensors are mounted inside the HMD housing behind the spectrally transmissive windows 800, as indicated by the dashed lines behind each window 800. The sensors within the HMD housing are sensitive to light in specific spectrums. In some embodiments, the spectrally transmissive windows 800 are infrared (IR) transmissive windows, and the spectrally specific sensors positioned behind the windows 800 are IR sensors (i.e., sensors configured to detect light in the IR spectrum). While the examples herein relate primarily to IR-transmissive windows and IR sensors, it should be understood that any reference herein to "IR-transmissive" can be replaced with "spectral-transmissive" for spectrums other than the IR spectrum, and "IR sensors" can be replaced with "spectral-specific sensors" to describe sensors configured to detect electromagnetic radiation in spectrums other than the IR spectrum. Furthermore, in place of sensors, multiple corresponding spectrum-specific beacons can be mounted inside the HMD housing behind the spectrally-transmissive window 800, with the beacons configured to emit light (electromagnetic radiation) of specific spectrums.

[0049] Thus, the HMD 100 can include a housing made of a spectrally transparent (IR-transparent) material, where the exterior surface of the housing is coated with an IR-opaque material and one or more locations on the exterior surface are devoid of the IR-opaque material, the location(s) corresponding to the window 800. One or more spectrally specific sensors (and / or beacons) can be disposed behind the housing at one or more locations corresponding to the window 800. In some embodiments, the exterior surface of the HMD housing is also coated with a spectrally transparent coating that covers the spectrally opaque material and one or more locations on the exterior surface that are devoid of the spectrally opaque material. Any suitable IR-transparent and IR-opaque materials known to those skilled in the art can be used herein to create the IR-transparent window 800 that allows electromagnetic radiation (light) in the IR spectrum to pass therethrough. For example, the IR-opaque material can include acrylic or paint configured to block electromagnetic radiation in the IR spectrum. The base material of the HMD housing can be IR-transparent polycarbonate plastic.

[0050] The thickness of the housing at the location(s) of the window(s) 800 may be thinner than the thickness of the remainder of the HMD housing. In this manner, if a sensor is mounted on the inner surface of the HMD housing directly behind the window 800, the sensor can be moved closer to the outer surface of the HMD housing, minimizing the size of the window 800. Thus, the size of each spectrally transmissive window 800 may be configurable based on the tolerances for installing the corresponding sensor behind the spectrally transmissive window 800. In some embodiments, a spectrally specific sensor is mounted inside the HMD housing behind the corresponding spectrally transmissive window 800 using an adhesive. The spectrally transmissive window 800 may be configured to filter (or block) electromagnetic radiation in at least one spectrum (e.g., the visible spectrum) while allowing electromagnetic radiation in a particular spectrum (e.g., light in the IR spectrum) to pass through the window 800.

[0051] As shown in FIG. 8 , multiple spectrally transmissive windows 800 may be provided on the housing of the HMD 100. At least some of the multiple spectrally transmissive windows 800 may be located on the front of the HMD 100, along the top of the HMD 100, along the bottom of the HMD 100, and / or along one or more sides of the front of the HMD 100. As shown in FIG. 8 , at least some of the windows 800 may be located on the top of the HMD 100, the bottom of the HMD 100, and / or on one or more sides of the HMD 100. Covering the HMD 100 in this manner provides optimal tracking using an optical tracking system that may include one or more beacons that emit electromagnetic radiation of a specific spectrum. For example, one or more beacons positioned within the environment of the HMD 100 may sweep a beam of IR light (e.g., a fan beam) across the play space, and an IR sensor disposed inside the HMD housing behind the IR-transmissive windows 800 may detect the beam sweep and, in some cases, detect a synchronization pulse emitted by the optical tracking system.

[0052] The processes described herein are described as a collection of blocks in a logical flow graph that represent a sequence of operations. The order in which the operations are described is not intended to be construed as a limitation, and any some of the described blocks may be combined in any order and / or in parallel to implement the process.

[0053] A process for manufacturing an HMD housing including a plurality of spectrally transmissive windows 800 may include forming an HMD housing made of a spectrally transmissive material (e.g., IR-transmissive polycarbonate plastic) at 902. As indicated by sub-block 904, forming the housing may include injection molding the HMD housing using injection molding techniques.

[0054] At 906, material can be removed from the inner surface of the HMD housing where the spectrally transmissive window 800 will be created. This removal of material reduces the thickness of the HMD housing only where the spectrally specific sensor (and / or beacon) will be positioned (e.g., worn), thereby allowing the sensor / beacon to be closer to the outer surface of the HMD housing when positioned (e.g., worn) next to the inner surface of the HMD housing behind the spectrally transmissive window 800. In this manner, positioning the sensor closer to the outer surface allows for a sensor field of view (FOV) having a particular angular range to be achieved while minimizing the size of the spectrally transmissive window 800. In some embodiments, removing material from the inner surface creates a recess in the HMD housing where the sensor / beacon will be positioned (e.g., worn). Removing material from the inner surface of the HMD housing also allows for the outer surface to remain flat and smooth (as opposed to creating a recess in the outer surface of the HMD housing).

[0055] At 908, the exterior surface of the HMD housing can be painted with a spectrally opaque material (e.g., coating the exterior surface of the housing with an IR-opaque film), which can include painting substantially the entire exterior surface of the HMD housing to cover the exterior surface with the spectrally opaque material.

[0056] At 910, the spectrally non-transparent material may be selectively removed from the exterior surface at locations where sensors / beacons are mounted behind. This creates spectrally transmissive windows 800 within the HMD housing. As indicated by sub-block 912, the selective material removal may include using laser etching techniques to remove the spectrally non-transparent material. In some embodiments, circular portions of the spectrally non-transparent material are removed to create circular spectrally transmissive windows 800 (sometimes referred to herein as "openings") within the HMD housing. In some embodiments, at block 910, a photolithography process may be used to remove the spectrally non-transparent material from the exterior surface at the locations of the sensors / beacons. In some embodiments, removing the spectrally opaque material in block 910 may include placing stickers on the exterior surface of the HMD housing in locations where spectrally transmissive window 800 will be created before block 908, then painting the exterior surface of the HMD housing with the spectrally opaque material in block 908, and removing the sticker to selectively remove the spectrally opaque material where the sticker was located to create spectrally transmissive window 800 in block 910. In some embodiments, a fixture having a pattern of pins may be moved before block 908 to a position where the pins will contact the exterior surface of the HMD housing, and while the pins are in contact with the exterior surface, painting the exterior surface of the HMD housing with the spectrally opaque material in block 908, and removing the pins from the HMD housing in block 910 to selectively "remove" the spectrally opaque material where the pins were located to create spectrally transmissive window 800 in those locations.Yet another method of creating a spectrally transmissive window 800 may be to apply an oleophobic coating onto the HMD housing in a particular pattern before block 908, and then in block 908 paint the exterior surface of the HMD housing with a spectrally non-transmissive material, at which point the spectrally non-transmissive material adheres to portions of the exterior surface that do not include the oleophobic coating and does not adhere to portions of the exterior surface that are coated with the oleophobic coating.

[0057] At 914, after removing the spectrally non-transparent material at selected locations, the exterior surface of the HMD housing can be painted with a spectrally transparent coating (e.g., a hard, clear coating material (or film) that is IR transparent) to create an HMD housing with a smooth exterior and a spectrally transparent window 800 that is nearly invisible to the naked eye, even in broad daylight. In dark environments, the spectrally transparent window 800 is at least unnoticeable, if not visible, to the naked eye, and the exterior surface of the HMD housing has a smooth appearance.

[0058] The disclosed process for manufacturing an HMD housing including multiple spectrally-transparent windows 800 is more cost-effective than manufacturing a similar HMD housing using a so-called “duplex” injection molding process, which involves fabricating a majority of the HMD housing from IR-non-transparent plastic and fabricating a small portion of the HMD housing from IR-transparent plastic to create a window over an IR sensor mounted inside the HMD housing. In contrast, the disclosed manufacturing process for creating spectrally-transparent (e.g., IR-transparent) windows 800 on an HMD housing involves using a general spectrally-transparent material as the base material for the HMD housing and then coating a majority of the HMD housing with a spectrally non-transparent material, which is more cost-effective compared to the duplex process for manufacturing an HMD housing including multiple spectrally-transparent windows 800. Because the HMD housing is made from a spectrally-transparent material, some light of a specific spectrum (e.g., IR light, if the specific spectrum is the IR spectrum) may pass through the spectrally-transparent window 800 to the underlying sensor, while some light of the specific spectrum may be internally reflected within the HMD housing itself. As a result, some light of a particular spectrum received through one spectrally transmissive window 800(1) may reach a nearby sensor (e.g., a sensor behind window 800(2)) due to these internal reflections. To mitigate the effect of internally reflected light of a particular spectrum on nearby spectrum-specific sensors, the spectrally transmissive material used as the base material of the HMD housing can be modified with an additive material that makes the HMD housing slightly more absorbing of light of a particular spectrum (e.g., slightly more IR absorbing), thereby reducing the degree of internal reflection.

[0059] Another method for manufacturing an HMD housing including multiple spectrally transmissive windows involves using a so-called "in-mold label." For example, a spectrally transmissive ink (e.g., an IR-transmissive ink) can be printed onto a plastic sheet in a specific pattern corresponding to the positioning of the spectrally transmissive windows on the HMD housing to be formed, the sheet with the printed spectrally transmissive ink thereon can be thermoformed into the desired shape of the HMD housing, and then a spectrally non-transmissive material can be overmolded onto the thermoformed sheet to create an HMD housing with spectrally transmissive windows. Yet another method for manufacturing an HMD housing including multiple spectrally transmissive windows involves a so-called "laser direct structuring" technique. For example, the HMD housing can be injection molded, a laser beam can be used to create a recessed pattern in the HMD housing, and a metallization process can plate metal over the recessed pattern in the HMD housing to create the spectrally transmissive windows in the HMD housing.

[0060] As described above, the thickness of the HMD housing at the location of the spectrally transmissive window 800 can be made as thin as possible (e.g., by using a subtractive manufacturing process that removes material from the inner surface of the HMD housing at these locations), while the remainder of the HMD housing can maintain a greater thickness to provide rigidity to the HMD housing. Having locally thinned portions of the HMD housing where the spectrally specific sensors / beacons are located means that the sensors can be positioned closer to the outer surface of the HMD housing, which reduces the amount of refraction and optical artifacts when light of a particular spectrum passes through the spectrally transmissive window 800. Because the sensors / beacons disposed behind the window 800 can be used in an optical tracking system that tracks the orientation of the HMD 100 as it moves within the volume, the reduced refraction and optical artifacts mean that more accurate spectrally specific (e.g., IR) beam sweep windows are achieved. Furthermore, the size of the spectrally transmissive window can limit the angular range over which each spectrally specific sensor receives light of a particular spectrum and / or the angular range over which a spectrally specific beacon can emit light of a particular spectrum. In some embodiments, the spectrally transmissive windows 800 are sized so that the sensor receives and / or the beacon emits light of a particular spectrum over an angular range of about 120 degrees. The goal may be to make the size of each spectrally transmissive window 800 as small as possible (e.g., for aesthetic purposes) without unduly restricting the angular range over which the sensor receives and / or the beacon emits light of a particular spectrum. In some embodiments, the diameter of an individual spectrally transmissive window may be in the range of 4 millimeters to 7 millimeters, or in the range of 6 millimeters to 6.5 millimeters.

[0061] It should be understood that optical tracking of the HMD 100 is just one example use of the spectrally specific sensors / beacons and spectrally transmissive window 800 described herein. For example, a spectrally specific camera (e.g., an IR camera) could be mounted internally within the HMD housing and below the spectrally transmissive window so as to remain unobtrusive when the HMD 100 is fully assembled. Such a camera could be a tracking camera or any other type of sensor configured to detect electromagnetic radiation in a particular spectrum.

[0062] The above can also be understood in light of the following provisions: 1. A head-mounted display (HMD), A rod connected to the intermediate frame of the HMD; a first movable frame coupled to the rod and the first lens barrel, the first movable frame being movable along the rod in a first direction toward the left side of the HMD or a second direction toward the right side of the HMD; a second movable frame coupled to the rod and the second lens barrel, the second movable frame being bidirectionally movable along the rod in a first direction or a second direction; an actuator on the bottom of the HMD, the actuator configured to be actuated by a user of the HMD; a movable elongated member coupled to the actuator and the intermediate frame, the movable elongated member being bidirectionally movable in a first direction or a second direction; a first biasing member coupled to the movable elongated member and the intermediate frame, the first biasing member configured to physically bias the movable elongated member in at least one of a first direction or a second direction; a rotatable gear coupled to the intermediate frame and disposed between the first and second movable frames, the rotatable gear engaging the movable elongated member; a second biasing member coupled to the rod, the second biasing member configured to physically bias the first moveable frame against a first helical protrusion extending from a face of the rotatable gear; a third biasing member coupled to the rod, the third biasing member configured to physically bias the second movable frame against a second helical protrusion extending from a face of the rotatable gear; A head-mounted display (HMD) in which actuation of the actuator causes movement of the movable elongated member in one of a first direction or a second direction, rotating a rotatable gear and moving the first movable frame and the second movable frame in opposite directions to adjust the spacing between the first lens barrel and the second lens barrel. 2. The HMD of clause 1, wherein the actuator comprises a knob that is slidable within a channel defined in a housing of the HMD. 3. The HMD of clause 1, wherein the actuator is located on at least one of the right half of the HMD or the left half of the HMD. 4. An HMD as described in clause 1, wherein the first helical protrusion and the second helical protrusion spiral inward from respective points on the circumference of the rotatable gear to respective points closer to the center of the rotatable gear than the respective points on the circumference. 5. the first movable frame includes a first wing member protruding from a back side of the first movable frame, the first wing member including a first opening; a first movable frame coupled to the rod by passing the rod through a first opening in the wing member; the second movable frame includes a second wing member protruding from a back side of the second movable frame, the second wing member including a second opening; 10. The HMD of claim 1, wherein a second movable frame is coupled to the rod by passing the rod through a second opening in the wing member. 6. A head-mounted display (HMD), a pair of lens barrels including a first lens barrel and a second lens barrel; A rod connected to the intermediate frame of the HMD; a pair of movable frames connected to the pair of lens barrels, the pair of movable frames being movable along the rod in a first direction toward the left side of the HMD or a second direction toward the right side of the HMD; an actuator accessible from outside the housing of the HMD; a movable elongated member coupled to the actuator and the intermediate frame; a first biasing member coupled to the movable elongated member and the intermediate frame, the first biasing member configured to resist movement of the movable elongated member in a direction of advancement of the elongated member; a rotatable gear coupled to the intermediate frame and disposed between the pair of movable frames, the rotatable gear engaging the movable elongated member; a pair of second biasing members connected to the rod, the pair of second biasing members configured to physically bias the pair of movable frames against a pair of helical protrusions extending from a face of the rotatable gear, a head-mounted display (HMD). 7. The HMD of clause 6, wherein the actuator comprises a knob slidable within a channel defined in a housing of the HMD. 8. The HMD of clause 6, wherein the actuator is located on at least one of the right half of the HMD or the left half of the HMD. 9. The HMD of clause 6, wherein a pair of helical protrusions spiral inward from respective points on the periphery of the rotatable gear to respective points closer to the center of the rotatable gear than the respective points on the periphery. 10. Each movable frame of the pair of movable frames includes a wing member protruding from a rear side of the movable frame, the wing member including an opening; 7. The HMD of clause 6, wherein the rod passes through an opening in a wing member of each movable frame. 11. An HMD as described in clause 10, wherein the pair of second biasing members are springs disposed on a rod, each spring extending between a stop connected to the rod and a corresponding one of the pair of movable frames' wing members. 12. The HMD of clause 6, wherein the movable elongate member is coupled to the intermediate frame by anchors that extend through channels defined in the movable elongate member. 13. A wearable display, a rod connected to an intermediate frame of the wearable display; a pair of movable frames coupled to the pair of lens assemblies and movable along the rod in a first direction toward the left side of the wearable display or a second direction toward the right side of the wearable display; an actuator accessible from outside the housing of the wearable display; a movable elongated member coupled to the actuator and the intermediate frame; a first biasing member coupled to the movable elongated member and the intermediate frame, the first biasing member configured to resist movement of the movable elongated member in a direction of advancement of the elongated member; a rotatable gear coupled to the intermediate frame and disposed between the pair of movable frames, the rotatable gear engaging the movable elongated member and having a face, a pair of helical projections extending from the face of the rotatable gear; a pair of second biasing members connected to the rod, the pair of second biasing members configured to physically bias the pair of movable frames against the pair of spiral protrusions. 14. The wearable display of clause 13, wherein the actuator comprises a knob movable within a channel defined in a housing of the wearable display. 15. A wearable display as described in clause 14, wherein movement of the knob toward a first end of the channel minimizes the spacing between a pair of lens assemblies, and movement of the knob toward a second end of the channel maximizes the spacing. 16. The wearable display of clause 13, wherein the actuator is located on at least one of the right half of the wearable display or the left half of the wearable display. 17. Each movable frame of the pair of movable frames includes a wing member protruding from a rear side of the movable frame, the wing member including an opening; 14. The wearable display of clause 13, wherein the rod passes through an opening in a wing member of each movable frame. 18. A wearable display as described in clause 17, wherein the pair of second biasing members are springs arranged on a rod, each spring extending between a stop connected to the rod and a wing member of a corresponding one of the pair of movable frames. 19. A wearable display as described in clause 13, wherein the movable elongate members are coupled to the intermediate frame by anchors extending through channels defined in the movable elongate members. 20. A wearable display as described in clause 13, wherein the first biasing member is a spring connected to a first end of the movable elongate member that is farthest from the actuator, and the spring is connected to the intermediate frame at a point closer to the actuator than the point at which the first end of the movable elongate member is connected to the actuator. 21. A head-mounted display (HMD), a pair of lens barrels coupled to a first portion of the HMD; an actuator disposed on a first side of the HMD, the actuator configured to be actuated by a user of the HMD; a first gear assembly disposed on a first side of the HMD and coupled to the actuator, the first portion of the HMD, and the second portion of the HMD, wherein the second portion of the HMD is bidirectionally movable relative to the first portion of the HMD; a second gear assembly disposed on a second side of the HMD opposite the first side of the HMD and coupled to the first portion of the HMD and the second portion of the HMD; a rod connecting the first gear assembly to the second gear assembly; A head-mounted display (HMD) in which actuation of an actuator causes movement of a first portion of the HMD relative to a second portion of the HMD in a first direction away from the second portion of the HMD or a second direction toward the second portion of the HMD. twenty two. the first gear assembly includes a first elongated member coupled to the second portion of the HMD and to the actuator, the first elongated member being bidirectionally movable in a first direction or a second direction; An HMD as described in clause 21, wherein the second gear assembly comprises a second elongated member connected to a second portion of the HMD, the second elongated member being movable bidirectionally in either the first direction or the second direction. twenty three. the first gear assembly further comprising a first rotatable gear and a second rotatable gear; a first elongated member engaged with the first rotatable gear; a first rotatable gear engaged with a second rotatable gear; a second rotatable gear coupled to the rod; the second gear assembly further comprising a third rotatable gear and a fourth rotatable gear; a third rotatable gear coupled to the rod; the third rotatable gear engages the fourth rotatable gear; 23. The HMD of clause 22, wherein a fourth rotatable gear engages the second elongated member. twenty four. the first elongated member having a first plurality of teeth on a top side of the first elongated member, the first plurality of teeth engaging teeth of the first rotatable gear; 23. An HMD as described in clause 22, wherein the second elongated member has a second plurality of teeth on a top side of the second elongated member, the second plurality of teeth engaging with the teeth of the fourth rotatable gear. 25. The HMD of clause 21, wherein the actuator is a rotatable knob. 26. the rotatable knob is depressible between a first position in which the rotatable knob is not depressed and a second position in which the rotatable knob is depressed; the rotatable knob is physically biased to a first position by a biasing member; the protrusion engages the detent to prevent the rotatable knob from rotating while the rotatable knob is in the first position; 26. The HMD of clause 25, wherein the rotatable knob is rotatable while the rotatable knob is in the second position such that the protrusion does not engage the detent or a different detent. 27. A head-mounted display (HMD), a pair of lens assemblies coupled to a first portion of the HMD; an actuator disposed on a first side of the HMD, the actuator being accessible from outside the housing of the HMD; A head-mounted display (HMD) comprising: a pair of gear assemblies disposed on opposite sides of the HMD, connected by a connecting rod, and coupled to a second part of the HMD that is movable relative to the first part of the HMD, wherein the gear assembly of the pair of gear assemblies disposed on the first side is further coupled to an actuator. 28. a gear assembly disposed on the first side, the gear assembly including a first elongated member coupled to the second portion of the HMD and the actuator, the first elongated member being bidirectionally movable in a first direction from the front of the HMD toward the rear of the HMD or in a second direction from the rear of the HMD toward the front of the HMD; An HMD as described in clause 27, wherein the second gear assembly comprises a second elongated member connected to a second portion of the HMD, the second elongated member being movable bidirectionally in either the first direction or the second direction. 29. the first gear assembly further comprising a first rotatable gear and a second rotatable gear; a first elongated member engaged with the first rotatable gear; a first rotatable gear engaged with a second rotatable gear; a second rotatable gear coupled to the connecting rod; the second gear assembly further comprising a third rotatable gear and a fourth rotatable gear; a third rotatable gear coupled to the connecting rod; the third rotatable gear engages the fourth rotatable gear; 29. The HMD of clause 28, wherein a fourth rotatable gear engages the second elongated member. 30. the first elongated member having a first plurality of teeth on a top side of the first elongated member, the first plurality of teeth engaging teeth of the first rotatable gear; 29. An HMD as described in clause 28, wherein the second elongated member has a second plurality of teeth on a top side of the second elongated member, the second plurality of teeth engaging with the teeth of the fourth rotatable gear. 31. The HMD of clause 27, wherein the actuator is a rotatable knob. 32. the rotatable knob is depressible between a first position in which the rotatable knob is not depressed and a second position in which the rotatable knob is depressed; the rotatable knob is physically biased to a first position by a biasing member; the protrusion engages the detent to prevent the rotatable knob from rotating while the rotatable knob is in the first position; 32. The HMD of clause 31, wherein while the rotatable knob is in the second position, the rotatable knob is rotatable such that the protrusion does not engage the detent or a different detent. 33. A wearable display, a pair of lens assemblies coupled to a first portion of the wearable display; a rotatable knob disposed on a first side of the wearable display, the rotatable knob being accessible from outside a housing of the wearable display; A wearable display comprising: a pair of gear assemblies disposed on opposite sides of the wearable display, connected by a connecting rod, and coupled to a second part of the wearable display that is movable relative to the first part of the wearable display, wherein the gear assembly of the pair of gear assemblies disposed on the first side is further coupled to a rotatable knob. 34. a gear assembly disposed on the first side, the gear assembly including a first elongated member coupled to the second portion of the wearable display and the rotatable knob, the first elongated member being bidirectionally movable in a first direction from the front of the wearable display toward the rear of the wearable display or in a second direction from the rear of the wearable display toward the front of the wearable display; A wearable display as described in clause 33, wherein the second gear assembly comprises a second elongated member connected to a second portion of the wearable display, the second elongated member being movable bidirectionally in either the first direction or the second direction. 35. the first gear assembly further comprising a first rotatable gear and a second rotatable gear; a first elongated member engaged with the first rotatable gear; a first rotatable gear engaged with a second rotatable gear; a second rotatable gear coupled to the connecting rod; the second gear assembly further comprising a third rotatable gear and a fourth rotatable gear; a third rotatable gear coupled to the connecting rod; the third rotatable gear engages the fourth rotatable gear; 35. The wearable display of clause 34, wherein a fourth rotatable gear engages the second elongate member. 36. the first elongated member having a first plurality of teeth on a top side of the first elongated member, the first plurality of teeth engaging teeth of the first rotatable gear; A wearable display as described in clause 34, wherein the second elongated member has a second plurality of teeth on a top side of the second elongated member, the second plurality of teeth engaging with teeth of the fourth rotatable gear. 37. A wearable display as described in clause 33, wherein the second portion of the wearable display is closer to the user's face when the user is wearing the wearable display, and the first portion of the wearable display is farther from the user's face when the user is wearing the wearable display. 38. the rotatable knob is depressible between a first position in which the rotatable knob is not depressed and a second position in which the rotatable knob is depressed; 34. The wearable display of clause 33, wherein the rotatable knob is physically biased to the first position by a biasing member. 39. the protrusion engages the detent to prevent the rotatable knob from rotating while the rotatable knob is in the first position; 39. A wearable display as described in clause 38, wherein while the rotatable knob is in the second position, the rotatable knob is rotatable such that the protrusion does not engage the detent or a different detent. 40. A wearable display as described in clause 33, wherein the distance between the user's face and the pair of lens assemblies of the wearable display is adjustable using a rotatable knob while the user is wearing the wearable display, without the user having to actuate any additional actuators. 41. A head-mounted display (HMD), a housing made of an infrared (IR) transparent material, an exterior surface of the housing coated with an IR non-transparent material, and one or more locations on the exterior surface devoid of the IR non-transparent material to provide one or more IR transparent windows on the housing; and one or more IR sensors disposed inside the housing behind one or more IR-transparent windows. 42. The HMD of clause 41, wherein the exterior surface is coated with an IR-transparent coating that substantially covers the IR-opaque material and one or more locations on the exterior surface that are devoid of the IR-opaque material. 43. An HMD as described in clause 41, wherein the thickness of the housing at one or more locations is less than the thickness of the remainder of the housing. 44. An HMD as described in clause 41, wherein one or more IR sensors are mounted on the interior surface of the housing behind one or more locations on the exterior surface. 45. An HMD as described in clause 41, wherein one or more locations on the exterior surface devoid of IR non-transparent material are circular in shape so as to provide a circular IR-transparent window within the housing. 45. An HMD as described in clause 41, wherein the housing is a housing for a main unit of the HMD, and the housing includes a plurality of IR-transparent windows. 46. ​​An HMD as described in clause 45, wherein at least some of the IR-transparent windows are located on the front of the HMD. 47. A method of manufacturing a head mounted display (HMD) having at least one window that allows electromagnetic radiation of a particular spectrum to pass through the at least one window, the method comprising: forming a housing for the HMD from a first material configured to allow a particular spectrum of electromagnetic radiation to pass therethrough; painting an exterior surface of the housing with a second material configured to block a particular spectrum of electromagnetic radiation; and removing the second material from at least one location on the exterior surface. 48. The method of clause 47, wherein removing the second material comprises laser etching the second material away from the exterior surface. 49. The method of clause 47, further comprising removing material from the inner surface of the housing behind at least one location on the outer surface to reduce the thickness of the housing at the at least one location. 50. The method of clause 47, further comprising coating the exterior surface with the first material or a third material configured to allow a particular spectrum of electromagnetic radiation to pass therethrough. 51. The method of clause 47, wherein forming the housing includes injection molding the housing. 52. The method of clause 47, further comprising mounting at least one sensor configured to detect electromagnetic radiation of a particular spectrum on the interior surface of the housing behind at least one location on the exterior surface. 53. The method of clause 47, further comprising mounting at least one beacon configured to emit electromagnetic radiation of a particular spectrum on the interior surface of the housing behind at least one location on the exterior surface. 54. The method of clause 47, wherein the specific spectrum is an infrared (IR) spectrum. 55. The method of clause 54, wherein the first material comprises IR transparent polycarbonate plastic. 56. a housing made of a spectrally transparent material configured to allow a particular spectrum of electromagnetic radiation to pass therethrough, wherein an exterior surface of the housing is coated with a spectrally non-transparent material configured to block the particular spectrum of electromagnetic radiation, and one or more locations on the exterior surface are devoid of the spectrally non-transparent material to provide one or more spectrally transparent windows on the housing; and one or more spectrally specific components disposed inside the housing behind one or more spectrally transmissive windows. 57. An electronic device as described in clause 56, wherein the exterior surface is coated with a spectrally non-transparent material and a spectrally transparent coating that substantially covers one or more locations on the exterior surface that are devoid of the spectrally non-transparent material. 58. The electronic device of clause 56, wherein the one or more spectrum-specific components are at least one of a sensor that detects electromagnetic radiation in a particular spectrum or a beacon that emits electromagnetic radiation in a particular spectrum. 59. An electronic device as described in clause 56, in which the thickness of the housing at one or more locations is less than the thickness of the remainder of the housing. 60. The electronic device of clause 56, wherein the specific spectrum is the infrared (IR) spectrum.

[0063] (Conclusion) Although various examples and embodiments are described individually herein, the examples and embodiments can be combined, rearranged, and modified to arrive at other variations within the scope of the present disclosure. Additionally, while the present subject matter has been described in language specific to structural features and / or methodological acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claims.

Claims

1. A head-mounted display (HMD), a rod connected to an intermediate frame of the HMD; a first movable frame coupled to the rod and a first lens barrel, the first movable frame being movable in both directions along the rod; a second movable frame coupled to the rod and a second lens barrel, the second movable frame being movable in both directions along the rod; an actuator on the bottom of the HMD, the actuator configured to be actuated by a user of the HMD; a movable elongated member coupled to the actuator and the intermediate frame, the movable elongated member being bidirectionally movable in a first direction or a second direction; a first biasing member coupled to the movable elongated member and the intermediate frame, the first biasing member configured to physically bias the movable elongated member in at least one of the first direction or the second direction; a rotatable gear coupled to the intermediate frame and disposed between the first movable frame and the second movable frame, the rotatable gear engaging the movable elongated member; a second biasing member coupled to the rod, the second biasing member configured to physically bias the first movable frame against the rotatable gear; and a third biasing member coupled to the rod, the third biasing member configured to physically bias the second movable frame against the rotatable gear; a head-mounted display (HMD) wherein actuation of the actuator causes movement of the movable elongated member in one of the first direction or the second direction, rotating the rotatable gear and moving the first movable frame and the second movable frame in opposite directions to adjust the spacing between the first lens barrel and the second lens barrel.

2. The HMD of claim 1 , wherein the actuator comprises a knob slidable within a channel defined in a housing of the HMD.

3. The HMD of claim 1 , wherein the actuator is located on at least one of a right half of the HMD or a left half of the HMD.

4. The rotatable gear is a first helical projection extending from a face of the rotatable gear; a second helical projection extending from the face of the rotatable gear; the second biasing member is configured to physically bias the first movable frame against the first helical protrusion; The HMD of claim 1 , wherein the third biasing member is configured to physically bias the second movable frame against the second helical protrusion.

5. 5. The HMD of claim 4, wherein the first spiral protrusion and the second spiral protrusion spiral inward from respective points on the circumference of the rotatable gear to respective points closer to a center of the rotatable gear than the respective points on the circumference.

6. A head-mounted display (HMD), a rod connected to an intermediate frame of the HMD; a pair of lens barrels connected to the rod, each of the lens barrels being movable in both directions along the rod; an actuator accessible from outside the housing of the HMD; a movable elongated member coupled to the actuator and the intermediate frame; a first biasing member coupled to the movable elongated member and the intermediate frame, the first biasing member configured to resist movement of the movable elongated member in a direction of advancement of the elongated member; a rotatable gear coupled to the intermediate frame and disposed between the pair of lens barrels, the rotatable gear engaging the movable elongated member; a pair of second biasing members connected to the rod, the pair of second biasing members configured to physically bias the pair of lens barrels toward the rotatable gear.

7. The HMD of claim 6 , wherein the actuator comprises a knob slidable within a channel defined in the housing of the HMD.

8. The HMD of claim 6 , wherein the actuator is located on at least one of the right half of the HMD or the left half of the HMD.

9. the pair of lens barrels are connected to the rod via a pair of movable frames; the rotatable gear includes a pair of helical projections extending from a face of the rotatable gear; The HMD of claim 6, wherein the pair of second biasing members are configured to physically bias the pair of movable frames against the pair of spiral protrusions, thereby physically biasing the pair of lens barrels toward the rotatable gear.

10. Each movable frame of the pair of movable frames includes a wing member protruding from a back side of the movable frame, the wing member including an opening; The HMD of claim 9 , wherein the rod passes through the opening in the wing member of each movable frame.

11. 11. The HMD of claim 10, wherein the pair of second biasing members are springs disposed on the rod, each spring extending between a stop connected to the rod and the wing member of a corresponding one of the pair of movable frames.

12. The HMD of claim 6 , wherein the movable elongate members are coupled to the intermediate frame by anchors that extend through channels defined in the movable elongate members.

13. A wearable display, a rod connected to an intermediate frame of the wearable display; a pair of lens assemblies coupled to the rod and movable bidirectionally along the rod; an actuator accessible from outside a housing of the wearable display; a movable elongated member coupled to the actuator and the intermediate frame; a first biasing member coupled to the movable elongated member and the intermediate frame, the first biasing member configured to resist movement of the movable elongated member in a direction of advancement of the elongated member; a rotatable gear coupled to the intermediate frame and disposed between the pair of lens assemblies, the rotatable gear engaging the movable elongated member; a pair of second biasing members connected to the rod, the pair of second biasing members configured to physically bias the pair of lens assemblies toward the rotatable gear.

14. The wearable display of claim 13 , wherein the actuator comprises a knob movable within a channel defined in the housing of the wearable display.

15. 15. The wearable display of claim 14, wherein movement of the knob toward a first end of the channel minimizes the spacing between the pair of lens assemblies, and movement of the knob toward a second end of the channel maximizes the spacing.

16. The wearable display of claim 13 , wherein the actuator is located on at least one of a right half of the wearable display or a left half of the wearable display.

17. the pair of lens assemblies are connected to the rod via a pair of movable frames, each of the pair of movable frames includes a wing member protruding from a back side of the movable frame, the wing member including an opening; The wearable display of claim 13 , wherein the rod passes through the opening in the wing member of each movable frame.

18. 18. The wearable display of claim 17, wherein the pair of second biasing members are springs disposed on the rod, each spring extending between a stop connected to the rod and the wing member of a corresponding one of the pair of movable frames.

19. the pair of lens assemblies are connected to the rod via a pair of movable frames; the rotatable gear includes a pair of helical projections extending from a face of the rotatable gear; The wearable display of claim 13, wherein the pair of second biasing members are configured to physically bias the pair of movable frames against the pair of spiral protrusions, thereby physically biasing the pair of lens assemblies toward the rotatable gear.

20. The wearable display of claim 13, wherein the first biasing member is a spring connected to a first end of the movable elongate member that is farthest from the actuator, and the spring is connected to the intermediate frame at a point closer to the actuator than the point at which the first end of the movable elongate member is connected to the actuator.

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