Positioning, stabilising, and interfacing structures and system incorporating same

Abstract

A positioning and stabilising structure for a head-mounted display system comprising: a pair of lateral portions, wherein: each lateral portion comprises a respective one of a pair of arm connection portions each configured to be connected to a respective one of a pair of arms extending posteriorly from a display unit housing on respective sides of the user's head; and each lateral portion comprises a rigidised portion being stiffer than one or more adjacent portions; wherein each rigidised portion comprises a first portion located within a frontal strap portion, a second portion located within a parietal strap portion and a third portion located within a occipital strap portion.

Description

POSITIONING, STABILISING, AND INTERFACING STRUCTURES AND SYSTEM INCORPORATING SAME

[0001] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in Patent Office patent files or records, but otherwise reserves all copyright rights whatsoever.1 CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Australian Patent Application No. 2024901116 filed 19 April 2024, Australian Patent Application No. 2024901509 filed 22 May 2024, Australian Patent Application No. 2024902627 filed 23 August 2024, and Australian Patent Application No. 2024904091 filed 10 December 2024, the entire contents of each of which is hereby incorporated by reference.2 BACKGROUND OF THE TECHNOLOGY2.1 FIELD OF THE TECHNOLOGY

[0003] The present technology relates generally to head mounted displays, positioning and stabilizing structures, user interfacing structures, and other components for use in head mounted displays, associated head-mounted display assemblies and systems including a display unit and positioning and stabilizing structure, interfacing structures and or components, and methods. The present technology finds particular application in the use of immersive reality head mounted displays and is herein described in that context. It is to be appreciated that the present technology may have broader application and may be used in any type of headmounted display arrangement including, but not limited to, virtual reality displays, augmented reality displays, and / or mixed reality displays.2.2 DESCRIPTION OF THE RELATED ART

[0004] It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.2.2.1 Immersive Technology

[0005] An immersive technology refers to technology that attempts to replicate or augment a physical environment through the means of a digital or virtual environment by creating a surrounding sensory feeling, thereby creating a sense of immersion.

[0006] In particular, an immersive technology provides the user visual immersion, and creates virtual objects and / or a virtual environment. The immersive technology may also provide immersion for at least one of the other five senses.2.2.2 Virtual Reality

[0007] Virtual reality (VR) is a computer-generated three-dimensional image or environment that is presented to a user. In other words, the environment may be entirely virtual. Specifically, the user observes an electronic screen in order to observe virtual or computer generated images in a virtual environment. Since the created environment is entirely virtual, the user may be blocked and / or obstructed from interacting with their physical environment (e.g., they may be unable to hear and / or see the physical objects in the physical environment that they are currently located).

[0008] The electronic screen may be supported in the user’s line of sight (e.g., mounted to the user’s head). While observing the electronic screen, visual feedback output by the electronic screen and observed by the user may produce a virtual environment intended to simulate an actual environment. For example, the user may be able to look around (e.g., 360°) by pivoting their head or their entire body, and interact with virtual objects observable by the user through the electronic screen. This may provide the user with an immersive experience where the virtual environment provides stimuli to at least one of the user’ s five senses, and replaces the corresponding stimuli of the physical environment while the user uses the VR device. Typically, the stimuli relates at least to the user’s sense of sight (i.e., because they are viewing an electronic screen), but other senses may also be included. The electronic screens are typically mounted to the user’s head so that they may be positioned in close proximity to the user’s eyes, which allows the user to easily observe the virtual environment.

[0009] The VR device may produce other forms of feedback in addition to, or aside from, visual feedback. For example, the VR device may include and / or be connected to a speaker in order to provide auditory feedback. The VR device may also include tactile feedback (e.g., in the form of haptic response), which may correspond to the visual and / or auditory feedback. This may create a more immersive virtual environment, because the user receives stimuli corresponding to more than one of the user’s senses.

[0010] While using a VR device, a user may wish to limit or block ambient stimulation. For example, the user may want to avoid seeing and / or hearing the ambient environment in order to better process stimuli from the VR device in the virtual environment. Thus, VR devices may limit and / or prevent the user’s eyes from receiving ambient light. In some examples, this may be done by providing a seal against the user’s face. In some examples, a shield may be disposed proximate to (e.g., in contact or close contact with) the user’s face, but may not seal against the user’s face. In either example, ambient light may not reach the user’s eyes, so that the only light observable by the user is from the electronic screen.

[0011] In other examples, the VR devices may limit and / or prevent the user’s ears from hearing ambient noise. In some examples, this may be done by providing the user with headphones (e.g., noise cancelling headphones), which may output sounds from the VR device and / or limit the user from hearing noises from their physical environment. In some examples, the VR device may output sounds at a volume sufficient to limit the user from hearing ambient noise.

[0012] In any example, the user may not want to become overstimulated (e.g., by both their physical environment and the virtual environment). Therefore, blocking and / or limiting the ambient from stimulating the user assists the user in focusing on the virtual environment, without possible distractions from the ambient.

[0013] Different types of VR devices are described below. Generally, a single VR device may include at least two different classifications. For example, the VR device may be classified by its portability and by how the display unit is coupled to the rest of the interface. These classifications may be independent, so that classification in one group (e.g., the portability of the unit) does not predetermineclassification into another group. There may also be additional categories to classify VR devices, which are not explicitly listed below.2.2.2.1 Portability2.2.2.1.1 Fixed Unit

[0014] In some forms, a VR device may be used in conjunction with a separate device, like a computer or video game console. This type of VR device may be fixed, since it cannot be used without the computer or video game console, and thus locations where it can be used are limited (e.g., by the location of the computer or video game console).

[0015] Since the VR device can be used in conjunction with the computer or video game console, the VR device may be connected to the computer or video game console. For example, an electrical cord may tether the two systems together. This may further “fix” the location of the VR device, since the user wearing the VR device cannot move further from the computer or video game console than the length of the electrical cord. In other examples, the VR device may be wirelessly connected (e.g., via Bluetooth, Wi-Fi, etc.), but may still be relatively fixed by the strength of the wireless signal.

[0016] The connection to the computer or video game console may provide control functions to the VR device. The controls may be communicated (i.e., through a wired connector or wirelessly) in order to help operate the VR device. In examples of a fixed unit VR device, these controls may be necessary in order to operate the display screen, and the VR device may not be operable without the connection to the computer or video game console.

[0017] In some forms, the computer or video game console may provide electrical power to the VR device, so that the user does not need to support a battery on their head. This may make the VR device more comfortable to wear, since the user does not need to support the weight of a battery.

[0018] The user may also receive outputs from the computer or video game console at least partially through the VR device, as opposed to through a television or monitor, which may provide the user with a more immersive experience while usingthe computer or video game console (e.g., playing a video game). In other words, the display output of the VR device may be substantially the same as the output from a computer monitor or television. Some controls and / or sensors necessary to output these images may be housed in the computer or video game console, which may further reduce the weight that the user is required to support on their body.

[0019] In some forms, movement sensors may be positioned remote from the VR device, and connected to the computer or video game console. For example, at least one camera may face the user in order to track movements of the user’s head. The processing of the data recorded by the camera(s) may be done by the computer or video game console, before being transmitted to the VR device. While this may assist in weight reduction of the VR device, it may also further limit where the VR device can be used. In other words, the VR device must be in the sight line of the camera(s).2.2.2.1.2 Portable Unit

[0020] In some forms, the VR device may be a self-contained unit, which includes a power source and sensors, so that the VR device does not need to be connected to a computer or video game console. This provides the user more freedom of use and movement. For example, the user is not limited to using the VR device near a computer or video game console, and could use the VR device outdoors, or in other environments that do not include computers or televisions.

[0021] Since the VR device is not connected to a computer or video game console in use, the VR device is required to support all necessary electronic components. This includes batteries, sensors, and processors. These components add weight to the VR device, which the user must support on their body. Appropriate weight distribution may be needed so that this added weight does not increase discomfort to a user wearing the VR device.

[0022] In some forms, the electrical components of the VR device are contained in a single housing, which may be disposed directly in front of the user’s face, in use. This configuration may be referred to as a “brick.” In this configuration, the center of gravity of the VR device without the positioning and stabilizing structure is directly in front of the user’s face. In order to oppose the moment created by the force of gravity, the positioning and stabilizing structure coupled to the brick configuration mustprovide a force directed into the user’s face, for example created by tension in headgear straps. While the brick configuration may be beneficial for manufacturing (e.g., since all electrical components are in close proximity) and may allow interchangeability of positioning and stabilizing structures (e.g., because they include no electrical connections), the force necessary to maintain the position of the VR device (e.g., tensile forces in headgear) may be uncomfortable to the user. Specifically, the VR device may dig into the user’s face, leading to irritation and markings on the user’s skin. The combination of forces may feel like “clamping” as the user’s head receives force from the display housing on their face and force from headgear on the back of their head. This may make a user less likely to wear the VR device.

[0023] As VR and other mixed reality devices may be used in a manner involving vigorous movement of the user’ s head and / or their entire body (for example during gaming), there may be significant forces / moments tending to disrupt the position of the device on the user’s head. Simply forcing the device more tightly against the user’s head to tolerate large disruptive forces may not be acceptable as it may be uncomfortable for the user or become uncomfortable after only a short period of time.

[0024] In some forms, electrical components may be spaced apart throughout the VR device, instead of entirely in front of the user’s face. For example, some electrical components (e.g., the battery) may be disposed on the positioning and stabilizing structure, particularly on a posterior contacting portion. In this way, the weight of the battery (or other electrical components) may create a moment directed in the opposite direction from the moment created by the remainder of the VR device (e.g., the display). Thus, it may be sufficient for the positioning and stabilizing structure to apply a lower clamping force, which in turn creates a lower force against the user’s face (e.g., fewer marks on their skin). However, cleaning and / or replacing the positioning and stabilizing structure may be more difficult in some such existing devices because of the electrical connections.

[0025] In some forms, spacing the electrical components apart may involve positioning some of the electrical components separate from the rest of the VR device. For example, a battery and / or a processor may be electrically connected, but carried separately from the rest of the VR device. Unlike in the “fixed units” described above,the battery and / or processor may be portable, along with the remainder of the VR device. For example, the battery and / or the processor may be carried on the user’s belt or in the user’s pocket. This may provide the benefit of reduced weight on the user’s head, but would not provide a counteracting moment. The tensile force provided by the positioning and stabilizing structure may still be less than the “brick” configuration, since the total weight supported by the head is less.2.2.2.2 Display Connection2.2.2.2.1 Integrated Display Screen

[0026] In some forms, the display screen is an integral piece of the VR device, and generally cannot be detached or removed from the rest of the VR device.

[0027] The display screen may be fixed within a housing, and protected from damage. For example, the display screen may be completely covered by the housing, which may reduce the occurrence of scratches. Additionally, integrating display screen with the rest of the VR device eliminates the occurrence of losing the display screen.

[0028] In these forms, the display screen functions purely as an immersive technology display. The vast majority of “fixed units” will include an integrated display screen. “Portable units” may include an integrated display screen, or may include a removable display screen (described below).2.2.2.2.2 Removable Display screen

[0029] In some forms, the display screen is a separate structure that can be removed from the VR device, and used separately.

[0030] In some forms, a portable electronic device (e.g., a cell phone) may be selectively inserted into a housing of the VR device. The portable electronic device may include most or all of the sensors and / or processors, and may create a virtual environment through a downloadable app.

[0031] Portable electronic devices are generally light weight, and may not require the positioning and stabilizing structure to apply a large force to the user’s head.2.2.3 Augmented Reality

[0032] In some forms, augmented reality (AR) is a computer-generated three- dimensional image or environment that is presented to a user.

[0033] While similar to VR, AR differs in that the virtual environment created at least in part by the electronic screen is observed in combination with the user’s physical environment. In other words, AR creates virtual objects in order to alter and / or enhance the user’s physical environment with elements of a virtual environment. The result of AR is a combined environment that includes physical and virtual objects, and therefore an environment that is both physical and virtual.

[0034] For example, images created by the electronic screen may be overlayed into the user’s physical environment. Only a portion of an AR combination environment presented to the user includes virtual objects. Thus, the user may wish to continue to receive ambient stimulation from their physical environment while using an AR device (e.g., in order to continue to observe the physical or non-virtual component of the combination environment).

[0035] Since AR may be used with the user’s physical environment, an AR device may not be electrically connected, or otherwise tethered, to a computer or video game console. Instead the AR device may include a battery, or other power source. This may provide the user with the greatest freedom of movement, so that they can explore a variety of physical environments while using the AR device.

[0036] This key difference between VR and AR may lead to different types of wearable electronic screens. As described above, a user of a VR device may wish to block ambient light, so the housing of the electronic screen may be opaque in order to limit or prevent ambient light from reaching the user. However, the user of an AR device may want to see the virtual environment blended with their actual environment. The electronic screen in an AR device may be similarly supported in front of the user’s eyes, but, screens in AR devices may be transparent or translucent, and the screens may not be supported by an opaque housing (or opaque material may not substantially obstruct the user’s line of sight). This may allow the user to continue receiving ambient stimulation, where the virtual environment is simultaneously present. Notwithstanding, some VR devices that do not have a transparent screenthrough which the user can see their real world surroundings may be configurable for AR by acquiring real-time video of the user’s real- world surroundings from the user’s perspective (e.g., with cameras on the display housing) and displaying it on the display screen.

[0037] Additionally, a person using an AR device may be more mobile than a person using a VR device (e.g., because an AR user can see their physical environment and / or are not tethered to a computer or video game console). Thus, a person using an AR device may wish to wear the device for an extended period of time, while also moving around (e.g., walking, running, biking, etc.). Including components, like batteries, on the AR device may make the AR device uncomfortable for the user’s head and / or neck, and may discourage the user from wearing the AR device for long periods of time.2.2.4 Mixed Reality

[0038] Mixed reality (MR) is similar to AR but may be more immersive because the MR device may provide the user more ways to interact with virtual objects or environment than an AR device. The virtual reality in MR may also be overlayed and / or blended with the user’s physical environment. Unlike AR however, a user may be able to interact with the virtual environment akin to what occurs in VR. In other words, while AR may present only a computer generated image in the physical environment, MR may present the user with the same or similar computer generated image but allow for interaction with the image in the physical environment (e.g., using a hand to “grab” an object produced virtually). Thus, the virtual environment may further merge with a physical environment so that the combined environment better replicates an actual environment.2.2.5 Head-Mounted Display Interface

[0039] A head-mounted display interface enables a user to have an immersive experience of a virtual environment and have broad application in fields such as communications, training, medical and surgical practice, engineering, and video gaming.

[0040] Different head-mounted display interfaces can each provide a different level of immersion. For example, some head-mounted display interfaces can providethe user with a total immersive experience. One example of a total immersive experience is virtual reality (VR). The head-mounted display interface can also provide partial immersion consistent with using an AR device.

[0041] VR head-mounted display interfaces typically are provided as a system that includes a display unit which is arranged to be held in an operational position in front of a user’s face. The display unit typically includes a housing containing a display and a user interface structure constructed and arranged to be in opposing relation with the user’s face. The user interface structure may extend about the display and define, in conjunction with the housing, a viewing opening to the display. The user interfacing structure may engage with the face and include a cushion for user comfort and / or be light sealing to block ambient light from the display. The headmounted display system further comprises a positioning and stabilizing structure that is disposed on the user’s head to maintain the display unit in position.

[0042] Other head-mounted display interfaces can provide a less than total immersive experience. In other words, the user can experience elements of their physical environment, as well as a virtual environment. Examples of a less than total immersive experience are augmented reality (AR) and mixed reality (MR).

[0043] AR and / or MR head-mounted display interfaces are also typically provided as a system that includes a display unit which is arranged to be held in an operational position in front of a user’s face. Likewise, the display unit typically includes a housing containing a display and a user interface structure constructed and arranged to be in opposing relation with the user’s face. The head-mounted display system of the AR and / or MR head-mounted display is also similar to VR in that it further comprises a positioning and stabilizing structure that is disposed on the user’s head to maintain the display unit in position. However, AR and / or MR head-mounted displays do not include a cushion that totally seals ambient light from the display, since these less than total immersive experience require an element of the physical environment. Instead, head-mounted displays in augmented and / or mixed allow the user to see the physical environment in combination with the virtual environment.

[0044] In any types of immersive technology, it is important that the headmounted display interface is comfortable in order to allow the user to wear the head-mounted display for extended periods of time. Additionally, it is important that the display is able to provide changing images with changing position and / or orientation of the user’ s head in order to create an environment, whether partially or entirely virtual, that is similar to or replicates one that is entirely physical.2.2.5.1 Interfacing structure

[0045] The head-mounted displays may include a user interfacing structure. Since it is in direct contact with the user’s face, the shape and configuration of the interfacing portion can have a direct impact on the effectiveness and comfort of the display unit.

[0046] The design of a user interfacing structure presents a number of challenges. The face has a complex three-dimensional shape. The size and shape of noses and heads varies considerably between individuals. Since the head includes bone, cartilage and soft tissue, different regions of the face respond differently to mechanical forces.

[0047] One type of interfacing structure extends around the periphery of the display unit and is intended to seal against the user’s face when force is applied to the user interface with the interfacing structure in confronting engagement with the user’s face. The interfacing structure may include a pad made of a polyurethane (PU). With this type of interfacing structure, there may be gaps between the interfacing structure and the face, and additional force may be required to force the display unit against the face in order to achieve the desired contact.

[0048] The regions not engaged at all by the user interface may allow gaps to form between the facial interface and the user’s face through which undesirable light pollution may ingress into the display unit (e.g., particularly when using virtual reality). The light pollution or “light leak” may decrease the efficacy and enjoyment of the overall immersive experience for the user. In addition, previous systems may be difficult to adjust to enable application for a wide variety of head sizes. Further still, the display unit and associated stabilizing structure may often be relatively heavy and may be difficult to clean which may thus further limit the comfort and useability of the system.

[0049] Another type of interfacing structure incorporates a flap seal of thin material positioned about a portion of the periphery of the display unit so as toprovide a sealing action against the face of the user. Like the previous style of interfacing structure, if the match between the face and the interfacing structure is not good, additional force may be required to achieve a seal, or light may leak into the display unit in-use. Furthermore, if the shape of the interfacing structure does not match that of the user, it may crease or buckle in-use, giving rise to undesirable light penetration.

[0050] A user interface may be partly characterised according to the design intent of where the interfacing structure is to engage with the face in-use. Some interfacing structures may be limited to engaging with regions of the user’s face that protrude beyond the arc of curvature of the face engaging surface of the interfacing structure. These regions may typically include the user’s forehead and cheek bones. This may result in user discomfort at localised stress points. Other facial regions may not be engaged at all by the interfacing structure or may only be engaged in a negligible manner that may thus be insufficient to increase the translation distance of the clamping pressure. These regions may typically include the sides of the user’s face, or the region adjacent and surrounding the users nose. To the extent to which there is a mismatch between the shape of the users’ face and the interfacing structure, it is advantageous for the interfacing structure or a related component to be adaptable in order for an appropriate contact or other relationship to form.2.2.5.2 Positioning and stabilizing

[0051] To hold the display unit in its correct operational position, the headmounted display system further comprises a positioning and stabilizing structure that is disposed on the user’s head. These structures may be responsible for providing forces to counter gravitational forces of the head-mounted display and / or interfacing structure. In the past these structures have been formed from expandable rigid structures that are typically applied to the head under tension to maintain the display unit in its operational position. Such systems have been prone to exert a clamping pressure on the user’s face which can result in user discomfort at localised stress points. Also, previous systems may be difficult to adjust to allow wide application head sizes. Further, the display unit and associated stabilizing structure are often heavy, difficult to clean which further limit the comfort and useability of the system.

[0052] Certain other head mounted display systems may be functionally unsuitable for the present field. For example, positioning and stabilizing structures designed for ornamental and visual aesthetics may not have the structural capabilities to maintain a suitable pressure around the face. For example, an excess of clamping pressure may cause discomfort to the user, or alternatively, insufficient clamping pressure on the users’ face may not effectively seal the display from ambient light.

[0053] Certain other head mounted display systems may be uncomfortable or impractical for the present technology. For example, if the system is used for prolonged time periods.

[0054] As a consequence of these challenges, some head mounted displays suffer from being one or more of obtrusive, aesthetically undesirable, costly, poorly fitting, difficult to use, and uncomfortable especially when worn for long periods of time or when a user is unfamiliar with a system. Wrongly sized positioning and stabilizing structures can give rise reduced comfort and in turn, shortened periods of use.

[0055] Therefore, an interfacing portion of a user interface used for the fully immersive experience of a virtual environment are subject to forces corresponding to the movement of a user during the experience.2.2.5.3 Materials

[0056] Materials used in head mounted display assemblies have included dense foams for contacting portions in the interfacing structures, rigid shells for the housings, and positioning and stabilizing structures formed from rigid plastic clamping structures. These materials have various drawbacks including not permitting the skin covered by the material to breath, being inflexible, difficult to clean and to prone trapping bacteria. As a result, products made with such material may be uncomfortable to wear for extended periods of time, causes skin irritation in some individuals and limit the application of the products.3 BRIEF SUMMARY OF THE TECHNOLOGY

[0057] The present technology may be directed toward providing positioning and stabilizing structures used in the supporting, stabilizing, mounting, utilizing, and / orsecuring of a head-mounted display having one or more of improved comfort, cost, efficacy, ease of use and manufacturability.

[0058] A first aspect of the present technology relates to apparatuses used in the supporting, stabilizing, mounting, utilizing, and / or securing of a head-mounted display.

[0059] Another aspect of the present technology relates to methods used in the supporting, stabilizing, mounting, utilizing, and / or securing of a head-mounted display.

[0060] Another aspect is a positioning and stabilizing structure for a headmounted display that comprising a rear (or posterior) support structure (or portion) arranged, in use, to contact a posterior region of the user’s head.

[0061] In some forms, the posterior support portion or at least a portion thereof is disposed posterior of the otobasion superior of the user.

[0062] In some forms, the posterior support portion is biased into contact with the occipital region of the user.

[0063] In some forms, the positioning and stabilizing structure further comprises opposing connectors that are disposed on opposing sides of, and extending along the temporal regions of, the user’s head to interconnect the posterior support portion to the head-mounted display unit. In some forms the positioning and stabilising structure comprises an anterior support portion connecting the posterior support portion to the head-mounted display unit.

[0064] The present technology may also be directed toward providing interfacing structures used in the supporting, cushioning, stabilizing, positioning, and / or sealing a head-mounted display in opposing relation with the user’s face.

[0065] Another aspect relates to apparatuses used in the supporting, cushioning, stabilizing, positioning, and / or sealing a head-mounted display in opposing relation with the user’s face.

[0066] Another aspect relates to methods used in supporting, cushioning, stabilizing, positioning, and / or sealing a head-mounted display in opposing relation with the user’s face.

[0067] Another aspect of the present technology relates to a head-mounted display system, comprising: a head-mounted display unit comprising a display unit housing comprising a display; and an interfacing structure constructed and arranged to engage the user’s face in use; and a positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a pair of arms attached in use to the display unit housing on respective sides thereof, the arms extending posteriorly from the display unit housing; a parietal strap portion configured to engage the user’s head at a region overlying the parietal bones of the user’s head in use, the parietal strap portion being connected to each of the pair of arms; wherein the parietal strap portion is semi-rigid to resist bending in superior and inferior directions in use; wherein the parietal strap portion comprises a predetermined shape whereby, on each lateral side of the user’s head, the parietal strap portion curves superiorly away from each of the arms.

[0068] A positioning and stabilising structure for a head-mounted display system, the head-mounted display system comprising a head-mounted display unit comprising a display unit housing comprising a display, the positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a parietal strap portion configured to engage the user’s head at a region overlying the parietal bones of the user’s head in use, the parietal strap portion being connected to each one of a pair of arms extending posteriorly in use from the display unit housing on respective sides thereof;wherein the parietal strap portion is semi-rigid to resist bending in superior and inferior directions in use; wherein the parietal strap portion comprises a predetermined shape whereby, on each lateral side of the user’s head, the parietal strap portion curves superiorly away from each of the arms.

[0069] In examples:• the parietal strap portion comprises a pair of anterior portions each connected to a respective one of the pair of arms, and a posterior portion connected to the anterior portions and configured to engage the region overlying the parietal bones of the user’s head;• the posterior portion of the parietal strap portion is formed at least partially from foam;• the posterior portion of the parietal strap portion comprises a textile covering;• the posterior portion of the parietal strap portion is constructed to have a predetermined curved shape;• the posterior portion of the parietal strap portion is dome shaped;• the posterior portion of the parietal strap portion is wider in a medial portion thereof than at lateral ends thereof;• the parietal strap portion is adjustable in length;• one or both of the anterior portions are moveable with respect to the posterior portion to adjust the length of the parietal strap portion;• one or both of the anterior portions are able to slide in the length direction of the posterior portion to extend from or retract into the posterior portion;• the parietal strap portion comprises one or more counterweights;• the parietal strap portion comprises a pair of counterweights, each spaced from and located on opposing sides of the mid-sagittal plane of the user’s head in use; the positioning and stabilising structure comprises a frontal strap portion constructed and arranged to engage the user’ s head in use in a region overlying the frontal bone of the user’s head;• the positioning and stabilising structure comprising a band strap portion constructed and arranged to encircle the user’s head in use, the band strap portion overlying the user’s forehead and forming an occipital strap portion constructed and arranged to engage a region of the user’s head overlying or lying inferior to the occipital bone in use;• the band strap portion is elastically extendable in length;• the band strap portion has an unextended length which is selectively adjustable;• the band strap portion comprises an occipital pad positioned in use to engage the region of the user’s head overlying or lying inferior to the occipital bone;• the occipital pad is formed from an elastomeric material;• the occipital pad is formed from foam;• the occipital pad comprises a textile outer layer;• lateral portions of the band strap portion are held apart from each other by the parietal strap portion prior to donning of the head-mounted display system by the user;• the band strap portion passes between two layers of the parietal strap portion on each lateral side of the user’s head in use;• the frontal strap portion comprises a forehead pad configured to engage the user’s forehead;• the forehead pad is formed at least partially from an elastomeric material;• the forehead pad is formed at least partially from a foam material;• the forehead pad is formed at least partially from a textile material;• the forehead pad comprises an elastomeric user-contacting surface;• the forehead pad is provided to the band strap portion;• the forehead pad is attached to the head-mounted display unit and the band strap portion overlies the forehead pad or engages the user’s forehead superior to the forehead pad;• the forehead pad comprises a frame and a cushion attached to the frame;• the frame of the forehead pad is attached to the head-mounted display unit;• the head-mounted display system comprises an interfacing structure connected to the display unit housing and constructed and arranged to engage the user’s face in use around a periphery of the user’s eye region;• the interfacing structure is constructed and arranged to engage sphenoid regions, cheek regions and the forehead region of the user’s face;• the head-mounted display system comprises a frontal connector constructed and arranged to connect between the frontal strap portion of the positioning and stabilising structure and each of the arms to support at least some weight of the head-mounted display unit in use via the arms;• the frontal connector comprises a pair of lateral portions each extending towards and attaching to a respective one of the arms;• the frontal connector is attached to a forwardmost portion of the each of the arms;• the positioning and stabilising structure comprises a top strap portion constructed and arranged to engage superior surfaces of the user’s head and connecting between the parietal strap portion and the frontal strap portion of the positioning and stabilising structure and / or the head-mounted display unit;• the top strap portion is constructed and arranged to connect between the parietal strap portion and the band strap portion;• the top strap portion is substantially aligned with the user’s mid-sagittal plane;• the parietal strap portion is connected to the occipital strap portion;• the positioning and stabilising structure comprises a posterior support portion engaging the user’s head in the region overlying the parietal bones and in the region overlying or lying inferior to the occipital bone;• the parietal support portion partially forms the posterior support portion;• the posterior support portion is connected to the occipital strap portion;• the occipital strap portion is connected to the posterior support portion by passing through one or more guides provided to the posterior support portion;• the posterior support portion is annular in shape;• the posterior support portion is formed from foam and / or textile materials;• the posterior support portion is thermoformed;• the posterior support portion is constructed to have a predetermined curved shape;• the predetermined curved shape of the posterior support portion comprises curvature in two orthogonal directions;• the posterior support portion comprises a superior portion and an inferior portion separated by a hinge region on each side of the posterior support portion, each hinge region constructed and arranged to encourage bending to occur at the hinge region;• the hinge region is constructed to have greater extensibility than the superior portion and the inferior portion of the posterior support portion;• the parietal strap portion comprises a cable routed therethrough;• the cable is routed between two layers of the parietal strap portion;• the band strap portion comprises a cable routed therethrough; and / or• the cable is routed between two layers of the band strap portion.

[0070] A positioning and stabilising structure for a head-mounted display system, the head-mounted display system comprising a head-mounted display unit comprising a display unit housing comprising a display, the positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a band strap portion constructed and arranged to encircle the user’s head in use, the band strap portion being connected to each one a pair of arms extending posteriorly in use from the display unit housing on respective sides thereof, the band strap portion forming: a frontal strap portion constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head; and an occipital strap portion configured to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use; a pair of rigidisers provided to respective lateral sides of the occipital strap portion, each rigidiser fixedly connected to a respective one of the pair of arms in use.

[0071] In examples: each of the rigidisers curves inferiorly away from the respective arm;• each of the rigidisers comprises a posterior end;• each of the rigidisers curves medially proximate the respective posterior end;• the respective posterior ends of the rigidisers are spaced apart in use;• each rigidiser is provided internally to the occipital strap portion;• the occipital strap portion is formed at least partially from foam;• the occipital strap portion comprises one or more textile outer layers;• the occipital strap portion is adjustable in length;• the occipital strap portion comprises a pair of anterior portions located on respective lateral sides of the user’s head in use and a posterior portion connecting the anterior portions of the occipital strap portion;• the posterior portion of the occipital strap portion comprises an unextended length that is selectively adjustable;• the posterior portion of the occipital strap portion is elastically extendable;• the positioning and stabilising structure comprises a parietal strap portion constructed and arranged to engage the user’ s head in use in a region overlying the parietal bones of the user’s head;• the parietal strap portion is connected to the band strap portion;• the parietal strap portion is formed at least partially from foam;• the parietal strap portion comprises one or more textile outer layers;• the parietal strap portion is adjustable in length;• the parietal strap portion comprises a pair of anterior portions located on respective lateral sides of the user’s head in use and a posterior portion connecting the anterior portions of the parietal strap portion;• the posterior portion of the parietal strap portion comprises an unextended length that is selectively adjustable;• the posterior portion of the parietal strap portion is elastically extendable;• the frontal strap portion of the positioning and stabilising structure is connected the head-mounted display unit in use to support at least some weight of the head-mounted display unit;• the head-mounted display system comprises a frontal connector constructed and arranged to connect between the frontal strap portion of the positioning and stabilising structure and each of the arms to support at least some weight of the head-mounted display unit in use via the arms;the frontal connector comprises a pair of lateral portions each extending towards and attaching to a respective one of the arms; and / or the frontal connector is attached to a forwardmost portion of the each of the arms.

[0072] In further examples:• the positioning and stabilising structure comprises a parietal strap portion constructed and arranged to engage the user’ s head in use in a region overlying the parietal bones of the user’s head; wherein the occipital strap portion comprises a pair of anterior portions located on respective lateral sides of the user’s head in use and a posterior portion connecting the anterior portions of the occipital strap portion, and wherein the parietal strap portion comprises a pair of anterior portions located on respective lateral sides of the user’s head in use and a posterior portion connecting the anterior portions of the parietal strap portion;• each anterior portion of the occipital strap portion is integrally formed with a respective one of the anterior portions of the parietal strap portion; and / or• each anterior portion of the occipital strap portion is integrally formed with the frontal strap portion.

[0073] Another aspect of the present technology relates to a head-mounted display system, comprising: a head-mounted display unit comprising a display unit housing comprising a display; and an interfacing structure constructed and arranged to engage the user’s face in use; and a positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a pair of arms attached in use to the display unit housing on respective sides thereof, the arms extending posteriorly from the display unit housing;a band strap portion constructed and arranged to encircle the user’s head in use, the band strap portion being connected to each of the pair of arms in use, the band strap portion forming: a frontal strap portion constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head; and an occipital strap portion configured to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use; a pair of rigidisers provided to respective lateral sides of the occipital strap portion, each rigidiser fixedly connected to a respective one of the pair of arms in use.

[0074] A positioning and stabilising structure for a head-mounted display system, the head-mounted display system comprising a head-mounted display unit comprising a display unit housing comprising a display, the positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a pair of lateral portions each constructed and arranged to be positioned on a respective lateral side of the user’s head in use, wherein: each lateral portion comprises a respective one of a pair of arm connection portions each configured to be connected to a respective one of a pair of arms extending posteriorly from the display unit housing on respective sides of the user’s head; and each lateral portion comprises a rigidised portion being stiffer than one or more adjacent portions; a frontal strap portion formed at least partially by the lateral portions, the frontal strap portion being constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head; 1a parietal strap portion formed at least partially by the lateral portions, the parietal strap portion constructed and arranged to engage the user’s head at a region overlying the parietal bones of the user’s head in use; an occipital strap portion formed at least partially by the lateral portions, the occipital strap portion constructed and arranged to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use; wherein each rigidised portion comprises a first portion located within the frontal strap portion, a second portion located within the parietal strap portion and a third portion located within the occipital strap portion.

[0075] In examples:• the lateral portions are able to conform to the shape of the user’s head;• in each rigidised portion, the first portion, the second portion and the third portion of said rigidised portion are all able to flex with respect to each other;• in each lateral portion, the respective rigidised portion extends from proximate the respective arm connection portion into each of the frontal strap portion, the parietal strap portion and the occipital strap portion;• each arm connection portion is constructed and arranged to fixedly connect to the respective one of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arm with respect to the arm connection portion;• the arm connection portions are constructed and arranged to fixedly connect to respective arms of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arms with respect to the rigidised portions;• in use, the positioning and stabilising structure is able to support substantially the entire weight of the head-mounted display unit via the arm connection portions;• the arm connection portions are constructed and arranged to form snap fit connections with the arms extending from the display unit housing;• each lateral portion is at least partially formed in a layered construction;• the layered construction comprises a user-facing layer facing the user’s head in use and a rigidiser on the opposite side of the user-facing layer to the user’s head in use, the rigidiser forming the rigidised portion of the respective lateral portion and constructed and arranged to stiffen the respective lateral portion in the rigidised portion;• the user-facing layer comprises a textile material forming a user-facing surface;• the user-facing layer comprises a laminate comprising a foam layer and the textile material;• the rigidiser is formed from a polymer material;• the rigidiser is formed by injection moulding;• the rigidiser is formed in a non-planar shape and imparts a three-dimensional curved shape to the respective lateral portion;• the three-dimensional curved shape imparted to the lateral portions approximates curvature of a head surface that each lateral portion engages in use;• the rigidiser is able to flex away from the non-planar shape in use to conform to the shape of the user’s head;• the layered construction comprises a non-user facing layer on an opposite side of the rigidiser to the user-facing layer;• the non-user facing layer comprises a textile material forming a non-user facing surface;• the non-user facing layer comprises a laminate comprising a foam layer and the textile material;• regions of the lateral portion not occupied by the rigidiser are formed at least partially by the user-facing layer and the non-user facing layer;• the layered construction comprises at least one stiffening layer proximate the arm connection portion;• the stiffening layer surrounds the arm connection portion;• the stiffening layer overlaps with the rigidiser;• the layered construction comprises two stiffening layers, the two stiffening layers overlapping with the rigidiser, a portion of the rigidiser being between the two stiffening layers;• each of the at least one stiffening layer comprises a stiffening mesh;• the frontal strap portion is adjustable in length;• the frontal strap portion comprises a first portion extending from one of the lateral portions, the first portion passing through an opening provided to the other of the lateral portions and being secured back to itself;• the parietal strap portion is adjustable in length;• the parietal strap portion comprises a first portion extending from one of the lateral portions, the first portion passing through an opening provided to the other of the lateral portions and being secured back to itself;• the occipital strap portion is adjustable in length;• the occipital strap portion comprises a first portion extending from one of the lateral portions, the first portion passing through an opening provided to the other of the lateral portions and being secured back to itself;• the parietal strap portion is constructed and arranged to support one or more counterweights;• the parietal strap portion is constructed and arranged to support a pair of counterweights, each spaced from and located on opposing sides of the mid- sagittal plane of the user’s head in use;• the lateral portions are constructed and arranged to support the pair of counterweights in the parietal strap portion;• the one or more counterweights are configured to attach to the parietal strap portion with a hook-and-loop connection;• the occipital strap portion is constructed and arranged to support one or more counterweights;• the occipital strap portion is constructed and arranged to support a pair of counterweights, each spaced from and located on opposing sides of the mid- sagittal plane of the user’s head in use;• the lateral portions are constructed and arranged to support the pair of counterweights in the occipital strap portion;• the one or more counterweights are configured to attach to the occipital strap portion with a hook-and-loop connection.

[0076] A positioning and stabilising structure for a head-mounted display system, the head-mounted display system comprising a head-mounted display unit comprising a display unit housing comprising a display, the positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a pair of lateral portions each constructed and arranged to be positioned on a respective lateral side of the user’s head in use, wherein: each lateral portion comprises a respective one of a pair of arm connection portions each configured to be connected to a respective one of a pair of arms extending posteriorly from the display unit housing on respective sides of the user’s head; and each lateral portion comprises a rigidised portion being stiffer than one or more adjacent portions; a frontal strap portion formed at least partially by the lateral portions, the frontal strap portion being constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head; a parietal strap portion formed at least partially by the lateral portions, the parietal strap portion constructed and arranged to engage the user’s head at a region overlying the parietal bones of the user’s head in use; an occipital strap portion formed at least partially by the lateral portions, the occipital strap portion constructed and arranged to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use; wherein each arm connection portion is constructed and arranged to fixedly connect to the respective one of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arm with respect to the arm connection portion.

[0077] In examples:• the arm connection portions are constructed and arranged to fixedly connect to respective arms of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arms with respect to the rigidised portions;• in use, the positioning and stabilising structure is able to support substantially the entire weight of the head-mounted display unit via the arm connection portions;• the arm connection portions are constructed and arranged to form snap fit connections with the arms extending from the display unit housing;• each rigidised portion comprises a first portion located within the frontal strap portion, a second portion located within the parietal strap portion and a third portion located within the occipital strap portion;• the lateral portions are able to conform to the shape of the user’s head;• in each rigidised portion, the first portion, the second portion and the third portion of said rigidised portion are all able to flex with respect to each other;• in each lateral portion, the respective rigidised portion extends from proximate the respective arm connection portion into each of the frontal strap portion, the parietal strap portion and the occipital strap portion.

[0078] In examples of any of the above aspects:• the interfacing structure comprises a cushion and a face engaging flange constructed and arranged to be provided around a periphery of an eye region of the user’s face and configured to engage the user’s face in use, the face engaging flange being flexible and resilient, the face engaging flange at least partially covering the cushion; and / or• the interfacing structure comprises a pair of cheek portions configured to engage the user’ s cheeks in use, a forehead portion configured to engage the user’s forehead in use, and a pair of sphenoid portions located on respective lateral sides of the interfacing structure connecting between the forehead portion and the cheek portions and configured to engage the user’s head proximate the sphenoid bone.

[0079] Another form of the present technology comprises a head mounted display system for a person comprising: a head-mounted display unit comprising a display; a control system for operation of the head-mounted display system; and a positioning and stabilizing structure configured to configured to hold the head-mounted display unit anterior to a user’s eyes such that the display is viewable by the user in use. The positioning and stabilising structure may be according any one of the above aspects.

[0080] The head-mounted display system may be helmet mounted, may be configured for virtual reality display, may be configured for augmented reality display, may be configured for mixed reality display.

[0081] In some examples: a) the head mounted display apparatus further comprises a light shield; b) the light shield is constructed and arranged to substantially obstruct in use the receipt of ambient light upon an eye region of the person; c) the light shield is configured for use in virtual reality display; d) the head-mounted display system comprises an interfacing structure constructed and arranged to contact in use an eye region of the person’s face; e) the interfacing structure is constructed from foam, silicone, and / or gel; f) the interfacing structure is constructed from a light absorbing material; and / or g) the interfacing structure is configured to function as a light shield.

[0082] In some examples: a) the head mounted display apparatus further comprises a sound system; b) a left ear transducer; and / or c) a right ear transducer.

[0083] In some examples: a) the head-mounted display unit comprises a binocular display unit; and / or b) the positioning and stabilizing structure is configured to maintain the binocular display unit in an operation position in use.

[0084] In some examples: a) the control system comprises a visual display controller and at least one battery; b) the at least one battery includes a first battery and a second battery; c) the first battery is a lower power system battery configured to power an RT clock; d) the second battery is a main battery; e) a battery supportconfigured to retain the battery; f) the battery support is connected to the positioning and stabilizing structure using a tether; g) an orientation sensor configured to sense the orientation of the person’s head in use; and / or h) a control support system.

[0085] In some examples: a) the positioning and stabilising structure comprises a frontal support portion configured to contact a region overlying a frontal bone of the person’s head; and / or (b) the positioning and stabilising structure comprises a length adjustment mechanism for adjusting a length of a portion of the positioning and stabilising structure.

[0086] Another aspect of one form of the present technology is a positioning and stabilizing structure that is constructed with a shape which is complementary to that of an intended wearer.

[0087] Another aspect of one form of the present technology is an interfacing structure that is constructed with a shape which is complementary to that of an intended wearer.

[0088] An aspect of one form of the present technology is a method of manufacturing apparatus.

[0089] An aspect of certain forms of the present technology is a positioning and stabilizing structure that is easy to use, e.g., by a person who has limited dexterity, vision or by a person with limited experience in using a head-mounted display.

[0090] An aspect of certain forms of the present technology is an interfacing structure that is easy to use, e.g., by a person who has limited dexterity, vision or by a person with limited experience in using a head-mounted display.

[0091] The methods, systems, devices and apparatus described may be implemented so as to improve the functionality of a head-mounted display, such as an electronic display or computer. Moreover, the described methods, systems, devices and apparatus can provide improvements in the technological field of virtual reality, augmented reality, and / or mixed reality.

[0092] Of course, portions of the aspects may form sub-aspects of the present technology. Also, various ones of the sub-aspects and / or aspects may be combined invarious manners and also constitute additional aspects or sub-aspects of the present technology.

[0093] Other features of the technology will be apparent from consideration of the information contained in the following detailed description, abstract, drawings and claims.4 BRIEF DESCRIPTION OF THE DRAWINGS

[0094] The present technology is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements including:4.1 HEAD-MOUNTED DISPLAY SYSTEMS

[0095] Fig. 1A shows a system including a user 100 wearing a head-mounted display system 1000, in the form of a face-mounted, virtual reality (VR) headset, displaying various images to the user 100. The user is standing while wearing the head-mounted display system 1000.

[0096] Fig. IB shows a system including a user 100 wearing a head-mounted display system 1000, in the form of a floating virtual reality (VR) headset, displaying various images to the user. The user is sitting while wearing the display interface 100.

[0097] Fig. 1C shows a system including a user 100 wearing a head-mounted display system 1000, in the form of a floating augmented reality (AR) headset, displaying various images to the user. The user is standing while wearing the headmounted display system 1000.4.2 DISPLAY SYSTEM AND FACIAL ANATOMY

[0098] Fig. 2A shows a view of a human upper airway including the nasal cavity, nasal bone, lateral nasal cartilage, greater alar cartilage, nostril, lip superior, lip inferior, larynx, hard palate, soft palate, oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

[0099] Fig. 2B is a front view of a face with several features of surface anatomy identified including the lip superior, upper vermilion, lower vermilion, lip inferior,mouth width, endocanthion, a nasal ala, nasolabial sulcus and cheilion. Also indicated are the directions superior, inferior, radially inward and radially outward.

[0100] Fig. 2C is a side view of a head with several features of surface anatomy identified including glabella, sellion, pronasale, subnasale, lip superior, lip inferior, supramenton, nasal ridge, alar crest point, otobasion superior and otobasion inferior. Also indicated are the directions superior & inferior, and anterior & posterior.

[0101] Fig. 2D is a further side view of a head. The approximate locations of the Frankfort horizontal and nasolabial angle are indicated. The coronal plane is also indicated.

[0102] Fig. 2E shows a base view of a nose with several features identified including naso-labial sulcus, lip inferior, upper Vermilion, naris, subnasale, columella, pronasale, the major axis of a naris and the midsagittal plane.

[0103] Fig. 2F shows a side view of the superficial features of a nose.

[0104] Fig. 2G shows subcutaneal structures of the nose, including lateral cartilage, septum cartilage, greater alar cartilage, lesser alar cartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue, frontal process of the maxilla and fibrofatty tissue.

[0105] Fig. 2H shows a medial dissection of a nose, approximately several millimeters from the midsagittal plane, amongst other things showing the septum cartilage and medial crus of greater alar cartilage.

[0106] Fig. 21 shows a front view of the bones of a skull including the frontal, nasal and zygomatic bones. Nasal concha are indicated, as are the maxilla, and mandible.

[0107] Fig. 2J shows a lateral view of a skull with the outline of the surface of a head, as well as several muscles. The following bones are shown: frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal, temporal and occipital. The mental protuberance is indicated. The following muscles are shown: digastricus, masseter, sternocleidomastoid and trapezius.

[0108] Fig. 2K shows an anterolateral view of a nose. The following bones are shown: frontal, supraorbital foramen, nasal, septal cartilage, lateral cartilage, orbit and infraorbital foramen.

[0109] Fig. 2L shows another front view of the face with several features of surface anatomy identified including the epicranius, the sphenoid, the nasal ridge, the outer and inner cheek regions, the zygomatic arch, and the alar crest.

[0110] Fig. 2M shows another side view of the face with several features of surface anatomy identified including the epicranius, the sphenoid, the nasal ridge, the outer and inner cheek regions, the zygomatic arch, and the alar crest.4.3 SHAPE OF STRUCTURES

[0111] Fig. 3A shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a positive sign, and a relatively large magnitude when compared to the magnitude of the curvature shown in Fig. 3B.

[0112] Fig. 3B shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a positive sign, and a relatively small magnitude when compared to the magnitude of the curvature shown in Fig. 3A.

[0113] Fig. 3C shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a value of zero.

[0114] Fig. 3D shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a negative sign, and a relatively small magnitude when compared to the magnitude of the curvature shown in Fig. 3E.

[0115] Fig. 3E shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a negative sign, and a relatively large magnitude when compared to the magnitude of the curvature shown in Fig. 3D.

[0116] Fig. 3F shows the surface of a structure, with a one dimensional hole in the surface. The illustrated plane curve forms the boundary of a one dimensional hole.

[0117] Fig. 3G shows a cross-section through the structure of Fig. 3F. The illustrated surface bounds a two dimensional hole in the structure of Fig. 3F.

[0118] Fig. 3H shows a perspective view of the structure of Fig. 3F, including the two dimensional hole and the one dimensional hole. Also shown is the surface that bounds a two dimensional hole in the structure of Fig. 3F.

[0119] Figs. 3L3J shows a seal forming structure. An exterior surface of the cushion is indicated. An edge of the surface is indicated. A path on the surface between points A and B is indicated. A straight-line distance between A and B is indicated. Two saddle regions and a dome region are indicated.

[0120] Fig. 3K illustrates a left-hand rule.

[0121] Fig. 3L illustrates a right-hand rule.

[0122] Fig. 3M shows a left ear, including the left ear helix.

[0123] Fig. 3N shows a right ear, including the right ear helix.

[0124] Fig. 30 shows a right-hand helix.4.4 HEAD-MOUNTED VIRTUAL REALITY DISPLAY

[0125] Fig. 4A shows a front perspective view of a head-mounted display interface in accordance with one form of the present technology.

[0126] Fig. 4B shows a rear perspective view of the head-mounted display of Fig. 4A.

[0127] Fig. 4C shows a perspective view of a positioning and stabilizing structure used with the head-mounted display of Fig. 4A.

[0128] Fig. 4D shows a front view of a user’s face, illustrating a location of an interfacing structure, in use.4.5 HEAD-MOUNTED AUGMENTED REALITY DISPLAY

[0129] Fig. 5A shows a front perspective view of a head-mounted display interface in accordance with one form of the present technology.

[0130] Fig. 5B shows a side view of the head-mounted display interface of Fig. 5A.4.6 CONTROLS

[0131] Fig. 6 shows a schematic view of a control system of one form of the present technology.4.7 POSITIONING AND STABILISING STRUCTURES

[0132] Fig. 7A shows a side view of a head-mounted display system according to another example of the present technology.

[0133] Fig. 7B shows a side view of a head-mounted display system according to another example of the present technology.

[0134] Fig. 7C shows a side view of a head-mounted display system according to another example of the present technology.

[0135] Fig. 7D shows a side view of a head-mounted display system according to another example of the present technology.

[0136] Fig. 7E shows a side view of a head-mounted display system according to another example of the present technology.

[0137] Fig. 7Fshows a perspective view of a positioning and stabilising structure for a head-mounted display system according to another example of the present technology.

[0138] Fig. 7G shows a side view of a lateral portion of the positioning and stabilising structure shown in Fig. 7F.

[0139] Fig. 7H shows a cross section view through section A- A as labelled in Fig. 7G.

[0140] Fig. 71 shows an exploded view of the lateral portion shown in Fig. 7G.

[0141] Fig. 7J shows a side view of the lateral portion shown in Fig. 7G with certain portions indicated.

[0142] Fig. 7K shows a side view of a rigidiser of the lateral portion shown in Fig. 7G.

[0143] Fig. 7L shows a side view of a first lateral portion of the positioning and stabilising structure shown in Fig. 7F.

[0144] Fig. 7M shows a side view of a second lateral portion of the positioning and stabilising structure shown in Fig. 7F.

[0145] Fig. 7N shows a perspective view of the positioning and stabilising structure shown in Fig. 7F with counterweights attached.

[0146] Fig. 70 shows a side view of a head-mounted display system including the positioning and stabilising structure shown in Fig. 7F when worn by a user.5 DETAILED DESCRIPTION OF EXAMPLES OF THETECHNOLOGY

[0147] Before the present technology is described in further detail, it is to be understood that the technology is not limited to the particular examples described herein, which may vary. It is also to be understood that the terminology used in this disclosure is for the purpose of describing only the particular examples discussed herein, and is not intended to be limiting.

[0148] The following description is provided in relation to various examples which may share one or more common characteristics and / or features. It is to be understood that one or more features of any one example may be combinable with one or more features of another example or other examples. In addition, any single feature or combination of features in any of the examples may constitute a further example.

[0149] In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in theclaims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure.5.1 IMMERSIVE TECHNOLOGIES

[0150] Immersive technologies may present a user with a combination of a virtual environment and the user’s physical environment, or the real world. The user may interact with the resulting immersive or combined reality.

[0151] The device immerses the user by augmenting or replacing stimuli associated with one of the user’s five senses with a virtual stimuli. Typically this is a virtual stimuli, although there could be additional stimuli that augment or replace stimuli associated with one of the additional four senses.

[0152] In some forms, a particular immersive technology may present a user with a combination of a virtual environment and the user’s environment. At least a portion of the resulting environment may include a virtual environment. In some examples, the entire resulting environment may be a virtual environment (e.g., meaning the user’s environment may be block from view or otherwise obstructed). In other forms, at least a portion of the user’s physical environment may still be visually observable.

[0153] In some forms, the user may use different types of immersive technologies, which may include, but are not limited to, virtual reality (VR), augmented reality (AR), or mixed reality (MR). Each type of immersive technology may present the user with a different environment and / or a different way to interact with the environment.

[0154] In some forms, a display system may be used with each type of immersive technology. A display screen of the display system may provide a virtual environment component to the combination environment (i.e., the combination of the virtual and user’s environments). In certain forms, the display screen may be an electronic screen.

[0155] In at least some types of immersive technologies (e.g., VR, AR, MR, etc.), positioning and stabilizing the electronic screen may be useful in operating a respective device. For example, the user may desire the electronic screen to be positioned close enough to their eyes to allow for easy viewing, but far enough away so as not to cause discomfort. Additionally, the electronic screen may need to be spaced far enough away so that users may simultaneously wear corrective lenses, like glasses. In addition, users may seek to maintain the orientation of the electronic screen relative to their eyes. In other words, users who walk, or otherwise move, while using these devices may not want the device to bounce or otherwise move on their head (e.g., particularly relative to their eyes), as this may cause dizziness and / or discomfort to the user. Therefore, these devices may be supported snuggly against the user’s head in order to limit relative movement between the user’s eyes and the device.

[0156] In one form, the present technology comprises a method for using a VR device comprising supporting the device on the user’s head proximate to at least one of the user’ s eyes, and within the user’ s line of sight.

[0157] In certain examples of the present technology, a head-mounted display unit is supported in front of both of the user’s eyes in order to block, obstruct, and / or limit ambient light from reaching the user’s eyes.

[0158] Any features disclosed below in the context of a device configured for VR are to be understood as being applicable to devices configured for AR, unless the context clearly requires otherwise. Likewise features disclosed below in the context of a device configured for AR are to be understood as being applicable to devices configured for VR, unless the context clearly requires otherwise. For the avoidance of doubt, a feature disclosed in the context of a device that does not have a transparent display, through which the user can view the real world, is to be understood as being applicable to a device having such a transparent display unless the context clearly requires otherwise. Likewise a feature disclosed in the context of a device that has a transparent display, through which the real-world can be viewed, is to be understood to be applicable to a device in which the display is electronic and through which the real- world cannot be viewed directly through a transparent material.5.2 VIRTUAL REALITY DISPLAY SYSTEM

[0159] As shown in Figs. 4A and 4B, a display apparatus, display system, display interface or head-mounted display system 1000 in accordance with one aspect of the present technology comprises the following functional aspects: an interfacing structure 1100, a head-mounted display unit 1200, and a positioning and stabilizing structure 1300. In some forms, a functional aspect may provide one or more physical components. In some forms, one or more physical components may provide one or more functional aspects. The head-mounted display unit 1200 may comprise a display. In use, the head-mounted display unit 1200 is arranged to be positioned proximate and anterior to the user’s eyes, so as to allow the user to view the display.

[0160] In other aspects, the head-mounted display system 1000 may also include a display unit housing 1205, an optical lens 1240, a controller 1270, a speaker 1272, a power source 1274, and / or a control system 1276. In some examples, these may be integral pieces of the head-mounted display system 1000, while in other examples, these may be modular and incorporated into the head-mounted display system 1000 as desired by the user.5.2.1 Head-mounted Display Unit

[0161] The head-mounted display unit 1200 may include a structure for providing an observable output to a user. Specifically, the head-mounted display unit 1200 is arranged to be held (e.g., manually, by a positioning and stabilizing structure, etc.) in an operational position in front of a user’s face.

[0162] In some examples, the head-mounted display unit 1200 may include a display screen 1220, a display unit housing 1205, an interfacing structure 1100, and / or an optical lens 1240. These components may be permanently assembled in a single head-mounted display unit 1200, or they may be separable and selectively connected by the user to form the head-mounted display unit 1200. Additionally, the display screen 1220, the display unit housing 1205, the interfacing structure 1100, and / or the optical lens 1240 may be included in the head-mounted display system 1000, but may not be part of the head-mounted display unit 1200.5.2.1.1 Display Screen

[0163] Some forms of the head-mounted display unit 1200 include a display, for example a display screen - not shown in Fig. 4B, but provided within the display housing 1205. The display screen may include electrical components that provide an observable output to the user.

[0164] In one form of the present technology, a display screen provides an optical output observable by the user. The optical output allows the user to observe a virtual environment and / or a virtual object.

[0165] The display screen may be positioned proximate to the user’s eyes, in order to allow the user to view the display screen. For example, the display screen may be positioned anterior to the user’s eyes. The display screen can output computer generated images and / or a virtual environment.

[0166] In some forms, the display screen is an electronic display. The display screen may be a liquid crystal display (LCD), or a light emitting diode (LED) screen.

[0167] In certain forms, the display screen may include a backlight, which may assist in illuminating the display screen. This may be particularly beneficial when the display screen is viewed in a dark environment.

[0168] In some forms, the display screen may extend wider a distance between the user’s pupils. The display screen may also be wider than a distance between the user’s cheeks.

[0169] In some forms, the display screen may display at least one image that is observable by the user. For example, the display screen may display images that change based on predetermined conditions (e.g., passage of time, movement of the user, input from the user, etc.).

[0170] In certain forms, portions of the display screen may be visible to only one of the user’s eyes. In other words, a portion of the display screen may be positioned proximate and anterior to only one of the user’s eyes (e.g., the right eye), and is blocked from view from the other eye (e.g., the left eye).

[0171] In one example, the display screen may be divided into two sides (e.g., a left side and a right side), and may display two images at a time (e.g., one image on either side).

[0172] Each side of the display screen may display a similar image. In some examples, the images may be identical, while in other examples, the images may be slightly different.

[0173] Together, the two images on the display screen may form a binocular display, which may provide the user with a more realistic VR experience. In other words, the user’s brain may process the two images from the display screen 1220 together as a single image. Providing two (e.g., un-identical) images may allow the user to view virtual objects on their periphery, and expand their field of view in the virtual environment.

[0174] In certain forms, the display screen may be positioned in order to be visible by both of the user’s eyes. The display screen may output a single image at a time, which is viewable by both eyes. This may simplify the processing as compared to the multi-image display screen.5.2.1.2 Display Housing

[0175] In some forms of the present technology as shown in Figs. 4A and 4B, a display unit housing 1205 provides a support structure for the display screen, in order to maintain a position of at least some of the components of the display screen relative to one another, and may additionally protect the display screen and / or other components of the head-mounted display unit 1200. The display unit housing 1205 may be constructed from a material suitable to provide protection from impact forces to the display screen. The display unit housing 1205 may also contact the user’s face, and may be constructed from a biocompatible material suitable for limiting irritation to the user.

[0176] A display unit housing 1205 in accordance with some forms of the present technology may be constructed from a hard, rigid or semi-rigid material, such as plastic.

[0177] In certain forms, the rigid or semi-rigid material may be at least partially covered with a soft and / or flexible material (e.g., a textile, silicone, etc.). This may improve biocompatibility and / or user comfort because the at least a portion of the display unit housing 1205 that the user engages (e.g., grabs with their hands) includes the soft and / or flexible material.

[0178] A display unit housing 1205 in accordance with other forms of the present technology may be constructed from a soft, flexible, resilient material, such as silicone rubber.

[0179] In some forms, the display unit housing 1205 may have a substantially rectangular or substantially elliptical profile. The display unit housing 1205 may have a three-dimensional shape with the substantially rectangular or substantially elliptical profile.

[0180] In certain forms, the display unit housing 1205 may include a superior face 1230, an inferior face 1232, a lateral left face 1234, a lateral right face 1236, and an anterior face 1238. The display screen 1220 may be held within the faces in use.

[0181] In certain forms, the superior face 1230 and the inferior face 1232 may have substantially the same shape.

[0182] In one form, the superior face 1230 and the inferior face 1232 may be substantially flat, and extend along parallel planes (e.g., substantially parallel to the Frankfort horizontal in use).

[0183] In certain forms, the lateral left face 1234 and the lateral right face 1236 may have substantially the same shape.

[0184] In one form, the lateral left face 1234 and the lateral right face 1236 may be curved and / or rounded between the superior and inferior faces 1230, 1232. The rounded and / or curved faces 1234, 1236 may be more comfortable for a user to grab and hold while donning and / or doffing the head-mounted display system 1000.

[0185] In certain forms, the anterior face 1238 may extend between the superior and inferior faces 1230, 1232. The anterior face 1238 may form the anterior most portion of the head-mounted display system 1000.

[0186] In one form, the anterior face 1238 may be a substantially planar surface, and may be substantially parallel to the coronal plane, while the head-mounted display system 1000 is worn by the user.

[0187] In one form, the anterior face 1238 may not have a corresponding opposite face (e.g., a posterior face) with substantially the same shape as the anterior face 1238. The posterior portion of the display unit housing 1205 may be at least partially open (e.g., recessed in the anterior direction) in order to receive the user’s face.

[0188] In some forms, the display screen is permanently integrated into the headmounted display system 1000. The display screen may be a device usable only as a part of the head-mounted display system 1000.

[0189] In some forms, the display unit housing 1205 may enclose the display screen, which may protect the display screen and / or limit user interference (e.g., moving and / or breaking) with the components of the display screen.

[0190] In certain forms, the display screen may be substantially sealed within the display unit housing 1205, in order to limit the collection of dirt or other debris on the surface of the display screen, which could negatively affect the user’s ability to view an image output by the display screen. The user may not be required to break the seal and access the display screen, since the display screen is not removable from the display unit housing 1205.

[0191] In some forms, the display screen is removably integrated into the headmounted display system 1000. The display screen may be a device usable independently of the head-mounted display system 1000 as a whole. For example, the display screen may be provided on a smart phone, or other portable electronic device.

[0192] In some forms, the display unit housing 1205 may include a compartment. A portion of the display screen may be removably receivable within the compartment. For example, the user may removably position the display screen in the compartment. This may be useful if the display screen performs additional functions outside of the head-mounted display unit 1200 (e.g., is a portable electronic device like a cellphone). Additionally, removing the display screen from the display unit housing 1205 may assist the user in cleaning and / or replacing the display screen.

[0193] Certain forms of the display housing include an opening to the compartment, allowing the user to more easily insert and remove the display screen from the compartment. The display screen may be retained within the compartment via a frictional engagement.

[0194] In certain forms, a cover may selectively cover the compartment, and may provide additional protection and / or security to the display screen 1220 while positioned within the compartment.

[0195] In certain forms, the compartment may open on the superior face. The display screen may be inserted into the compartment in a substantially vertical direction while the display interface 1000 is worn by the user.5.2.1.3 Interfacing Structure

[0196] As shown in Figs. 4A and 4B, some forms of the present technology include an interfacing structure 1100 is positioned and / or arranged in order to conform to a shape of a user’s face, and may provide the user with added comfort while wearing and / or using the head-mounted display system 1000.

[0197] In some forms, the interfacing structure 1100 is coupled to a surface of the display unit housing 1205.

[0198] In some forms, the interfacing structure 1100 may extent at least partially around the display unit housing 1205, and may form a viewing opening. The viewing opening may at least partially receive the user’s face in use. Specifically, the user’s eyes may be received within the viewing opening formed by the interfacing structure 1100.

[0199] In some forms, the interfacing structure 1100 in accordance with the present technology may be constructed from a biocompatible material.

[0200] In some forms, the interfacing structure 1100 in accordance with the present technology may be constructed from a soft, flexible, and / or resilient material.

[0201] In certain forms, the interfacing structure 1100 in accordance with the present technology may be constructed from silicone rubber and / or foam.

[0202] In some forms, the interfacing structure 1100 may contact sensitive regions of the user’s face, which may be locations of discomfort. The material forming the interfacing structure 1100 may cushion these sensitive regions, and limit user discomfort while wearing the head-mounted display system 1000.

[0203] In certain forms, these sensitive regions may include the user’s forehead. Specifically, this may include the region of the user’s head that is proximate to the frontal bone, like the Epicranius and / or the glabella. This region may be sensitive because there is limited natural cushioning from muscle and / or fat between the user’s skin and the bone. Similarly, the ridge of the user’s nose may also include little to no natural cushioning.

[0204] In some forms, the interfacing structure 1100 may comprise a single element. In some embodiments the interfacing structure 1100 may be designed for mass manufacture. For example, the interfacing structure 1100 may be designed to comfortably fit a wide range of different face shapes and sizes.

[0205] In some forms, the interfacing structure 1100 may include different elements that overlay different regions of the user’s face. The different portions of the interfacing structure 1100 may be constructed from different materials, and provide the user with different textures and / or cushioning at different regions.5.2.1.3.1 Light Shield

[0206] Some forms of the head-mounted display system 1000 may include a light shield that may be constructed from an opaque material and can block ambient light from reaching the user’s eyes. The light shield may be part of the interfacing structure 1100 or may be a separate element. In some examples the interfacing structure 1100 may form a light shield by shielding the user’s eyes from ambient light, in addition to providing a comfortable contacting portion for contact between the head-mounted display 1200 and the user’s face. In some examples a light shield may be formed from multiple components working together to block ambient light.

[0207] In certain forms, the light shield can obstruct ambient light from reaching an eye region, which may be formed on regions of the Epicranius, the user’s sphenoid, across the outer cheek region between the sphenoid to the left or right zygomatic arch, over the zygomatic arch, across the inner cheek region from the zygomatic arches towards the alar crests, and on the users’ nasal ridge inferior to the sellion to enclose a portion of the users’ face therebetween.

[0208] In one form, the light shield may not contact the user’s face around its entire perimeter. For example, the light shield may be spaced from the user’s nasal rigid. The width of this spacing may be substantially small, so as to substantially limit the ingress of ambient light. However, the user’s nasal ridge may be sensitive and easily irritated. Thus, avoiding direct contact with the user’s nasal ridge may improve user comfort while wearing the head-mounted display system 1000.

[0209] In certain forms, the light shield may be a portion of the display unit housing 1205, and may be integrally or removably coupled to the display unit housing 1205. In one form, if the display unit housing 1205 is usable with a display screen outputting AR or MR, and VR, the light shield may be removable from the display unit housing 1205, and only coupled to the display unit housing 1205 while using VR.5.2.1.3.1.1 Seal-forming structure

[0210] As shown in Fig. 4D, in one form of the present technology, the interfacing structure 1100 acts as a seal-forming structure, and provides a target sealforming region. The target seal-forming region is a region on the seal-forming structure where sealing may occur. The region where sealing actually occurs- the actual sealing surface- may change within a given session, from day to day, and from user to user, depending on a range of factors including but not limited to, where the display unit housing 1205 is placed on the face, tension in the positioning and stabilizing structure 1300, and / or the shape of a user’s face.

[0211] In one form the target seal-forming region is located on an outside surface of the interfacing structure 1100.

[0212] In some forms, the light shield may form the seal-forming structure and seal against the user’s face.

[0213] In certain forms, the entire perimeter of the light shield or interfacing structure 1100 may seal against the user’s skin, and can block ambient light from reaching an eye region. The eye region may be formed on regions of the Epicranius, the user’s sphenoid, across the outer cheek region between the sphenoid to the left or right zygomatic arch, over the zygomatic arch, across the inner cheek region from the zygomatic arches towards the alar crests, and on the users’ nasal ridge inferior to the sellion to enclose a portion of the users’ face therebetween.

[0214] When acting as a seal-forming structure, the light shield or interfacing structure 1100 may contact sensitive areas the user’s face, like the user’s nasal ridge. This contact may entirely prevent the ingress of ambient light. Sealing around the entire perimeter of the display unit housing 1205 may improve performance of the head-mounted display system 1000. Additionally, biocompatible materials may be selected so that direct contact with the user’s nasal ridge does not significantly reduce user comfort while wearing the head-mounted display system 1000.

[0215] In certain forms of the present technology, a system is provided comprising more than one interfacing structure 1100, each being configured to correspond to a different size and / or shape range. For example the system may comprise one form of interfacing structure 1100 suitable for a large sized head, but not a small sized head and another suitable for a small sized head, but not a large sized head. The different interfacing structures 1100 may be removable and replaceable so that different users with different sized heads may use the same headmounted display system 1000.

[0216] In some forms, the seal-forming structure may be formed on regions of the Epicranius, the user’s sphenoid, across the outer cheek region between the sphenoid to the left or right zygomatic arch, over the zygomatic arch, across the inner cheek region from the zygomatic arches towards the alar crests, and on the users’ nasal ridge inferior to the sellion to enclose a portion of the users’ face therebetween. This defined region may be an eye region.

[0217] In certain forms, this may seal around the user’s eyes. The seal created by the seal-forming structure or interfacing structure 1100 may create a light seal, in order to limit ambient light from reaching the user’s eyes.5.2.1.3.2 Material Biocompatibility

[0218] Biocompatible materials are considered to be materials that undergo a full evaluation of their biological responses, relevant to their safety in use, according to ISO 10993-1 standard. The evaluation considers the nature and duration of anticipated contact with human tissues when in-use. In some forms of the present technology, the materials utilised in the positioning and stabilizing structure and interfacing structure may undergo at least some of the following biocompatibility tests: Cytotoxicity - Elution Test (MeM Extract): ANSVAAMVISO 10993-5; Skin Sensitisation: ISO 10993-10; Irritation: ISO 10993-10; Genotoxicity - Bacterial Mutagenicity Test: ISO 10993-3; Implantation: ISO 10993-6.5.2.1.4 Optical Lenses

[0219] As shown in Fig. 4B, at least one lens 1240 may be disposed between the user’s eyes and the display screen 1220. The user may view an image provided by the display screen 1220 through the lens 1240. The at least one lens 1240 may assist in spacing the display screen 1220 away from the user’s face to limit eye strain. The at least one lens 1240 may also assist in better observing the image being displayed by the display screen 1220.

[0220] In some forms, the lenses 1240 are Fresnel lenses.

[0221] In some forms, the lens 1240 may have a substantially frustoconical shape. A wider end of the lens 1240 may be disposed proximate to the display screen 1220, and a narrower end of the lens 1240 may be disposed proximate to the user’s eyes, in use.

[0222] In some forms, the lens 1240 may have a substantially cylindrical shape, and may have substantially the same width proximate to the display screen 1220, and proximate to the user’s eyes, in use.

[0223] In some forms, the at least one lens 1240 may also magnify the image of the display screen 1220, in order to assist the user in viewing the image.

[0224] In some forms, the head-mounted display system 1000 includes two lenses 1240 (e.g., binocular display), one for each of the user’s eyes. In other words, each of the user’s eyes may look through a separate lens positioned anterior to therespective pupil. Each of the lenses 1240 may be identical, although in some examples, one lens 1240 may be different than the other lens 1240 (e.g., have a different magnification).

[0225] In certain forms, the display screen 1220 may output two images simultaneously. Each of the user’s eyes may be able to see only one of the two images. The images may be displayed side-by-side on the display screen 1220. Each lens 1240 permits each eye to observe only the image proximate to the respective eye. The user may observe these two images together as a single image.

[0226] In some forms, the posterior perimeter of each lens 1240 may be approximately the size of the user’s orbit. The posterior perimeter may be slightly larger than the size of the user’s orbit in order to ensure that the user’s entire eye can see into the respective lens 1240. For example, the outer edge of the each lens 1240 may be aligned with the user’s frontal bone in the superior direction (e.g., proximate the user’s eyebrow), and may be aligned with the user’s maxilla in the inferior direction (e.g., proximate the outer cheek region).

[0227] The positioning and / or sizing of the lenses 1240 may allow the user to have approximately 360° of peripheral vision in the virtual environment, in order to closely simulate the physical environment.

[0228] In some forms, the head-mounted display system 1000 includes a single lens 1240 (e.g., monocular display). The lens 1240 may be positioned anterior to both eyes (e.g., so that both eyes view the image from the display screen 1220 through the lens 1240), or may be positioned anterior to only one eye (e.g., when the image from the displace screen 1220 is viewable by only one eye).5.2.1.4.1 Lens Mounting

[0229] The lenses 1240 may be coupled to a spacer positioned proximate to the display screen 1220 (e.g., between the display screen 1220 and the interfacing structure 1100), so that the lenses 1240 are not in direct contact with the display screen 1220 (e.g., in order to limit the lenses 1240 from scratching the display screen 1220).

[0230] For example, the lenses 1240 may be recessed relative to the interfacing structure 1100 so that the lenses 1240 are disposed within the viewing opening. In use, each of the user’s eyes are aligned with the respective lens 1240 while the user’s face is received within the viewing opening (e.g., an operational position).

[0231] In some forms, the anterior perimeter of each lens 1240 may encompass approximately half of the display screen 1220. A substantially small gap may exist between the two lenses 1240 along a center line of the display screen 1220. This may allow a user looking through both lenses 1240 to be able to view substantially the entire display screen 1220, and all of the images being output to the user.

[0232] In certain forms, the center of the display screen 1220 (e.g., along the center line between the two lenses 1240) may not output an image. For example, in a binocular display (e.g., where each side of the display screen 1220 outputs substantially the same image), each image may be spaced apart on the display screen 1220. This may allow two lenses 1240 to be positioned in close proximity to the display screen 1220, while allowing the user to view the entirety of the image displayed on the display screen 1220.

[0233] In some forms, a protective layer 1242 may be formed around at least a portion of the lenses 1240. In use, the protective layer 1242 may be positioned between the user’s face and the display screen 1220.

[0234] In some forms, a portion of each lens 1240 may project through the protective layer 1242 in the posterior direction. For example, the narrow end of each lens 1240 may project more posterior than the protective layer 1242 in use.

[0235] In some forms, the protective layer 1242 may be opaque so that light from the display screen 1220 is unable to pass through. Additionally, the user may be unable to view the display screen 1220 without looking through the lenses 1240.

[0236] In some forms, the protective layer 1242 may be non-planar, and may include contours that substantially match contours of the user’s face. For example, a portion of the protective layer 1242 may be recessed in the anterior direction in order to accommodate the user’s nose.

[0237] In certain forms, the user may not contact the protective layer 1242 while wearing the head-mounted display system 1000. This may assist in reducing irritation from additional contact with the user’s face (e.g., against the sensitive nasal ridge region).5.2.1.4.2 Corrective Lenses

[0238] In some examples, additional lenses may be coupled to the lenses 1240 so that the user looks through both the lens 1240 and the additional lens in order to view the image output by the display screen 1220.

[0239] In some forms, the additional lenses are more posterior than the lenses 1240, in use. Thus, the additional lenses are positioned closer to the user’s eyes, and the user looks through the additional lenses before looking through the lenses 1240.

[0240] In some forms, the additional lenses may have a different magnification than the lenses 1240.

[0241] In some forms, the additional lenses, may be prescription strength lenses. The additional lenses may allow a user to view the display screen 1220 without glasses, which may be uncomfortable to wear while using the head-mounted display system 1000. The additional lenses may be removable so that users that do not require the additional lenses may still clearly view the display screen 1220.5.2.2 Positioning and stabilizing structure

[0242] As shown in Figs. 4A and 4B, the display screen 1220 and / or the display unit housing 1205 of the head-mounted display system 1000 of the present technology may be held in position in use by the positioning and stabilizing structure 1300.

[0243] To hold the display screen 1220 and / or the display unit housing 1205 in its correct operational position, the positioning and stabilizing structure 1300 is ideally comfortable against the user’s head in order to accommodate the induced loading from the weight of the display unit in a manner that minimise facial markings and / or pain from prolonged use. There is also need to allow for a universal fit without trading off comfort, usability and cost of manufacture. The design criteria may include adjustability over a predetermined range with low-touch simple set up solutions that have a low dexterity threshold. Further considerations include cateringfor the dynamic environment in which the head-mounted display system 1000 may be used. As part of the immersive experience of a virtual environment, users may communicate, i.e., speak, while using the head-mounted display system 1000. In this way, the jaw or mandible of the user may move relative to other bones of the skull. Additionally, the whole head may move during the course of a period of use of the head-mounted display system 1000. For example, movement of a user’s upper body, and in some cases lower body, and in particular, movement of the head relative to the upper and lower body.

[0244] In one form the positioning and stabilizing structure 1300 provides a retention force to overcome the effect of the gravitational force on the display screen 1220 and / or the display unit housing 1205.

[0245] In one form of the present technology, a positioning and stabilizing structure 1300 is provided that is configured in a manner consistent with being comfortably worn by a user. In one example the positioning and stabilizing structure 1300 has a low profile, or cross-sectional thickness, to reduce the perceived or actual bulk of the apparatus. In one example, the positioning and stabilizing structure 1300 comprises at least one strap having a rectangular cross-section. In one example the positioning and stabilizing structure 1300 comprises at least one flat strap.

[0246] In one form of the present technology, a positioning and stabilizing structure 1300 is provided that is configured so as not to be too large and bulky to prevent the user from comfortably moving their head from side to side.

[0247] In one form of the present technology, a positioning and stabilizing structure 1300 comprises a strap constructed from a laminate of a textile usercontacting layer, a foam inner layer and a textile outer layer. In one form, the foam is porous to allow moisture, (e.g., sweat), to pass through the strap. In one form, a skin contacting layer of the strap is formed from a material that helps wick moisture away from the user’s face. In one form, the textile outer layer comprises loop material to engage with a hook material portion.

[0248] In certain forms of the present technology, a positioning and stabilizing structure 1300 comprises a strap that is extensible, e.g., resiliently extensible. For example the strap may be configured in use to be in tension, and to direct a force todraw the display screen 1220 and / or the display unit housing 1205 toward a portion of a user’s face, particularly proximate to the user’s eyes and in line with their field of vision. In an example the strap may be configured as a tie.

[0249] In one form of the present technology, the positioning and stabilizing structure 1300 comprises a first tie, the first tie being constructed and arranged so that in use at least a portion of an inferior edge thereof passes superior to an otobasion superior of the user’s head and overlays a portion of a parietal bone without overlaying the occipital bone.

[0250] In one form of the present technology, the positioning and stabilizing structure 1300 includes a second tie, the second tie being constructed and arranged so that in use at least a portion of a superior edge thereof passes inferior to an otobasion inferior of the user’s head and overlays or lies inferior to the occipital bone of the user’s head.

[0251] In one form of the present technology, the positioning and stabilizing structure 1300 includes a third tie that is constructed and arranged to interconnect the first tie and the second tie to reduce a tendency of the first tie and the second tie to move apart from one another.

[0252] In certain forms of the present technology, a positioning and stabilizing structure 1300 comprises a strap that is bendable and e.g., non-rigid. An advantage of this aspect is that the strap is more comfortable against a user’ s head.

[0253] In certain forms of the present technology, a positioning and stabilizing structure 1300 comprises a strap constructed to be breathable to allow moisture vapour to be transmitted through the strap,

[0254] In certain forms of the present technology, a system is provided comprising more than one positioning and stabilizing structure 1300, each being configured to provide a retaining force to correspond to a different size and / or shape range. For example the system may comprise one form of positioning and stabilizing structure 1300 suitable for a large sized head, but not a small sized head, and another. Suitable for a small sized head, but not a large sized head.

[0255] In some forms, the positioning and stabilizing structure 1300 may include cushioning material (e.g., a foam pad) for contacting the user’s skin. The cushioning material may provide added wearability to the positioning and stabilizing structure 1300, particularly if positioning and stabilizing structure 1300 is constructed from a rigid or semi-rigid material.5.2.2.1 Temporal Connectors

[0256] As shown in Fig. 4C, some forms of the head-mounted display system 1000 or positioning and stabilizing structure 1300 include temporal connectors 1250, each of which may overlay a respective one of the user’s temporal bones in use. A portion of the temporal connectors 1250, in-use, are in contact with a region of the user’s head proximal to the otobasion superior, i.e., above each of the user’s ears. In some examples, temporal connectors are strap portions of a positioning and stabilising structure 1300. In other examples, temporal connectors are arms of a head-mounted display unit 1200. In some examples a temporal connector of a head-mounted display system 1000 may be formed partially by a strap portion (e.g., a lateral strap portion 1330) of a positioning and stabilising structure 1300 and partially by an arm 1210 of a head-mounted display unit 1200.

[0257] The temporal connectors 1250 may be lateral portions of the positioning and stabilizing structure 1300, as each temporal connector 1250 is positioned on either the left or the right side of the user’s head.

[0258] In some forms, the temporal connectors 1250 may extend in an anterior- posterior direction, and may be substantially parallel to the sagittal plane.

[0259] In some forms, the temporal connectors 1250 may be coupled to the display unit housing 1205. For example, the temporal connectors 1250 may be connected to lateral sides of the display unit housing 1205. For example, each temporal connector 1250 may be coupled to a respective one of the lateral left face 1234 and the lateral right face 1236.

[0260] In certain forms, the temporal connectors 1250 may be pivotally connected to the display unit housing 1205, and may provide relative rotation between each temporal connector 1250, and the display unit housing 1205.

[0261] In certain forms, the temporal connectors 1250 may be removably connected to the display unit housing 1205 (e.g., via a magnet, a mechanical fastener, hook and loop material, etc.).

[0262] In some forms, the temporal connectors 1250 may be arranged in-use to run generally along or parallel to the Frankfort Horizontal plane of the head and superior to the zygomatic bone (e.g., above the user’s cheek bone).

[0263] In some forms, the temporal connectors 1250 may be positioned against the user’s head similar to arms of eye-glasses, and be positioned more superior than the anti-helix of each respective ear.

[0264] In some forms, the temporal connectors 1250 may have a generally elongate and flat configuration. In other words, each temporal connector 1250 is far longer and wider (direction from top to bottom in the paper plane) than thick (direction into the paper plane).

[0265] In some forms, the temporal connectors 1250 may each have a three- dimensional shape which has curvature in all three axes (X, Y and Z). Although the thickness of each temporal connector 1250 may be substantially uniform, its height varies throughout its length. The purpose of the shape and dimension of each temporal connector 1250 is to conform closely to the head of the user in order to remain unobtrusive and maintain a low profile (e.g., not appear overly bulky).

[0266] In some forms, the temporal connectors 1250 may be constructed from a rigid or semi-rigid material, which may include plastic, hytrel (thermoplastic polyester elastomer), or another similar material. The rigid or semi-rigid material may be self- supporting and / or able to hold its shape without being worn. This can make it more intuitive or obvious for users to understand how to use the positioning and stabilizing structure 1300 and may contrast with a positioning and stabilizing structure 1300 that is entirely floppy and does not retain a shape. Maintaining the temporal connectors 1250 in the in-use state prior to use may prevent or limit distortion whilst the user is donning the positioning and stabilizing structure 1300 and allow a user to quickly fit or wear the head-mounted display system 1000.

[0267] In certain forms, the temporal connectors 1250 may be rigidizers, which may allow for a more effective (e.g., direct) translation of tension through the temporal connectors 1250 because rigidizers limit the magnitude of elongation or deformation of the arm while in-use.

[0268] In certain forms, the positioning and stabilizing structure 1300 may be designed so that the positioning and stabilizing structure 1300 springs ‘out of the box’ and generally into its in-use configuration. In addition, the positioning and stabilizing structure 1300 may be arranged to hold its in-use shape once out of the box (e.g., because rigidizers may be formed to maintain the shape of some or part of the positioning and stabilizing structure 1300). Advantageously, the orientation of the positioning and stabilizing structure 1300 is made clear to the user as the shape of the positioning and stabilizing structure 1300 is generally curved much like the rear portion of the user’s head. That is, the positioning and stabilizing structure 1300 is generally dome shaped.

[0269] In certain forms, a flexible and / or resilient material may be disposed around the rigid or semi-rigid material of the temporal connectors 1250. The flexible material may be more comfortable against the user’s head, in order to improve wearability and provide soft contact with the user’s face. In one form, the flexible material is a textile sleeve at is permanently or removably coupled to each temporal connector 1250.

[0270] In one form, a textile may be over-moulded onto at least one side of the rigidizer. In one form, the rigidizer may be formed separately to the resilient component and then a sock of user contacting material (e.g., Breath-O-Prene™) may be wrapped or slid over the rigidizer. In alternative forms, the user contacting material may be provided to the rigidizer by adhesive, ultrasonic welding, sewing, hook and loop material, and / or stud connectors.

[0271] In some forms, the user contacting material may be on both sides of the rigidizer, or alternatively may only be on the user contacting side (e.g., the user contacting side) of the rigidizer to reduce bulk and cost of materials.

[0272] In some forms, the temporal connectors 1250 are constructed from a flexible material (e.g., a textile), which may be comfortable against the user’s skin, and may not require an added layer to increase comfort.5.2.2.2 Posterior support portion

[0273] As shown in Fig. 4C, some forms of the positioning and stabilizing structure 1300 may include a posterior support portion 1350 for assisting in supporting the display screen 1220 and / or the display unit housing 1205 (shown in Fig. 4B) proximate to the user’s eyes. The posterior support portion 1350 may assist in anchoring the display screen and / or the display unit housing 1205 to the user’s head in order to appropriately orient the display screen proximate to the user’ s eyes.

[0274] In some forms, the posterior support portion 1350 may be coupled to the display unit housing 1205 via the temporal connectors 1250.

[0275] In certain forms, the temporal connectors 1250 may be directly coupled to the display unit housing 1205 and to the posterior support portion 1350.

[0276] In some forms, the posterior support portion 1350 may have a three- dimensional contour curve to fit to the shape of a user’s head. For example, the three- dimensional shape of the posterior support portion 1350 may have a generally round three-dimensional shape adapted to overlay a portion of the parietal bone and the occipital bone of the user’s head, in use.

[0277] In some forms, the posterior support portion 1350 may be a posterior portion of the positioning and stabilizing structure 1300. The posterior support portion 1350 may provide an anchoring force directed at least partially in the anterior direction.

[0278] In certain forms, the posterior support portion 1350 is the inferior-most portion of the positioning and stabilizing structure 1300. For example, the posterior support portion 1350 may contact a region of the user’s head between the occipital bone and the trapezius muscle. The posterior support portion 1350 may hook against an inferior edge of the occipital bone (e.g., the occiput). The posterior support portion 1350 may provide a force directed in the superior direction and / or the anterior direction in order to maintain contact with the user’s occiput.

[0279] In certain forms, the posterior support portion 1350 is the inferior-most portion of the entire head-mounted display system 1000. For example, the posterior support portion 1350 may be positioned at the base of the user’s neck (e.g., overlaying the occipital bone and the trapezius muscle more inferior than the user’s eyes) so that the posterior support portion 1350 is more inferior than the display screen 1220 and / or the display unit housing 1205.

[0280] In some forms, the posterior support portion 1350 may include a padded material, which may contact the user’s head (e.g., overlaying the region between the occipital bone and the trapezius muscle). The padded material may provide additional comfort to the user, and limit marks caused by the posterior support portion 1350 pulling against the user’s head.5.2.2.3 Forehead Support

[0281] Some forms of the positioning and stabilizing structure 1300 may include a forehead support or frontal support portion 1360 configured to contact the user’s head superior to the user’s eyes, while in use. The positioning and stabilising structure 1300 shown in Fig. 5B includes a forehead support 1360. In some examples the positioning and stabilising structure 1300 shown in Fig. 4A may include a forehead support 1360. The forehead support 1360 may overlay the frontal bone of the user’s head. In certain forms, the forehead support 1360 may also be more superior than the sphenoid bones and / or the temporal bones. This may also position the forehead support 1360 more superior than the user’s eyebrows.

[0282] In some forms, the forehead support 1360 may be an anterior portion of the positioning and stabilizing structure 1300, and may be disposed more anterior on the user’s head than any other portion of the positioning and stabilizing structure 1300. The posterior support portion 1350 may provide a force directed at least partially in the posterior direction.

[0283] In some forms, the forehead support 1360 may include a cushioning material (e.g., textile, foam, silicone, etc.) that may contact the user, and may help to limit marks caused by the straps of the positioning and stabilizing structure 1300. The forehead support 1360 and the interfacing structure 1100 may work together in order to provide comfort to the user.

[0284] In some forms, the forehead support 1360 may be separate from the display unit housing 1205, and may contact the user’s head at a different location (e.g., more superior) than the display unit housing 1205.

[0285] In some forms, the forehead support 1360 can be adjusted to allow the positioning and stabilizing structure 1300 to accommodate the shape and / or configuration of a user’s face.

[0286] In some forms, the temporal connectors 1250 may be coupled to the forehead support 1360 (e.g., on lateral sides of the forehead support 1360). The temporal connectors 1250 may extend at least partially in the inferior direction in order to couple to the posterior support portion 1350.

[0287] In certain forms, the positioning and stabilizing structure 1300 may include multiple pairs of temporal connectors 1250. For example, one pair of temporal connectors 1250 may be coupled to the forehead support 1360, and one pair of temporal connectors 1250 may be coupled to the display unit housing 1205.

[0288] In some forms, the forehead support 1360 can be presented at an angle which is generally parallel to the user’s forehead to provide improved comfort to the user. For example, the forehead support 1360 may position the user in an orientation that overlays the frontal bone, and is substantially parallel to the coronal plane. Positioning the forehead support substantially parallel to the coronal plane can reduce the likelihood of pressure sores which may result from an uneven presentation.

[0289] In some forms, the forehead support 1360 may be offset from a rear support or posterior support portion that contacts a posterior region of the user’s head (e.g., an area overlaying the occipital bone and the trapezius muscle). In other words, an axis along a rear strap would not intersect the forehead support 1360, which may be disposed more inferior and anterior than the axis along the rear strap. The resulting offset between the forehead support 1360 and the rear strap may create moments that oppose the weight force of the display screen 1220 and / or the display unit housing 1205. A larger offset may create a larger moment, and therefore more assistance in maintaining a proper position of the display screen 1220 and / or the display unit housing 1205. The offset may be increased by moving the forehead support 1360closer to the user’s eyes (e.g., more anterior and inferior along the user’s head), and / or increasing the angle of the rear strap so that it is more vertical.5.2.2.4 Adjustable Straps

[0290] As shown in Fig. 4C, portions of the positioning and stabilizing structure 1300 may be adjustable, in order to impart a selective tensile force on the display screen 1220 and / or the display unit housing 1205 in order to secure a position of the display screen 1220 and / or the display unit housing 1205.

[0291] In some forms, the display unit housing 1205 may include at least one loop or eyelet 1254 (as shown in Fig. 4B), and at least one of the temporal connectors 1250 may be threaded through that loop, and doubled back on itself. The length of the temporal connector 1250 threaded through the respective eyelet 1254 may be selected by the user in order to adjust the tensile force provided by the positioning and stabilizing structure 1300. For example, threading a greater length of the temporal connector 1250 through the eyelet 1254 may supply a greater tensile force.

[0292] In some forms, at least one of the temporal connectors 1250 may include an adjustment portion 1256 and a receiving portion 1258 (as shown in Fig. 4C). The adjustment portion 1256 may be positioned through the eyelet 1254 on the display unit housing 1205, and may be coupled to the receiving portion 1258 (e.g., by doubling back on itself). The adjustment portion 1256 may include a hook material, and the receiving portion 1258 may include a loop material (or vice versa), so that the adjustment portion 1256 may be removably held in the desired position. In some examples, the hook material and the loop material may be Velcro.

[0293] In certain forms, adjusting the position of the adjustment portion 1256 relative to the receiving portion 1258 may apply a posterior force to the display screen 1220 and / or the display unit housing 1205, and increase or decrease a sealing force of the light shield against the user’s head (e.g., when the light shield acts as a sealforming structure).

[0294] In certain forms, the adjustment portion 1256 may be constructed from a flexible and / or resilient material, which may conform to a shape of the user’s head and / or may allow the adjustment portion to be threaded through the eyelet 1254. For example, the adjustment portion(s) 1256 may be constructed from an elastic textile,which may provide an elastic, tensile force. The remainder of the temporal connectors 1250 may be constructed from the rigid or semi-rigid material described above (although it is contemplated that additional sections of the temporal connectors 1250 may also be constructed from a flexible material).5.2.2.4.1 Top Strap

[0295] In some forms, the positioning and stabilizing structure 1300 may include a top strap portion, which may overlay a superior region of the user’s head. The headmounted display system 1000 shown in Fig. 1A has a top strap portion, for example.

[0296] In some forms, the top strap portion may extend between an anterior portion of the head-mounted display system 1000 and a posterior region of the headmounted display system 1000.

[0297] In some forms, the top strap portion may be constructed from a flexible material, and may be configured to compliment the shape of the user’s head.

[0298] In certain forms, the top strap portion may be connected to the display unit housing 1205. For example, the top strap portion may be coupled to the superior face 1230. The top strap portion may also be coupled to the display unit housing 1205 proximate to a posterior end of the display unit housing 1205.

[0299] In certain forms, the top strap portion may be coupled to the forehead support 1360. For example, the top strap portion may be coupled to the forehead support 1360 proximate to a superior edge. The top strap portion may be connected to the display unit housing 1205 through the forehead support 1360.

[0300] In some forms, the top strap portion may be connected to the posterior support portion 1350. For example, the top strap portion may be connected proximate to a superior edge of the posterior support portion 1350.

[0301] In some forms, the top strap portion may overlay the frontal bone and the parietal bone of the user’s head.

[0302] In certain forms, the top strap portion may extend along the sagittal plane as it extends between the anterior and posterior portions of the head-mounted display system 1000.

[0303] In certain forms, the top strap portion may apply a tensile force oriented at least partially in the superior direction, which may oppose the force of gravity.

[0304] In certain forms, the top strap portion may apply a tensile force oriented at least partially in the posterior direction, which may pull the interfacing structure 1100 toward the user’s face (and supply a portion of the sealing force when the light shield acts as a seal-forming structure).

[0305] In some forms, the top strap portion may be adjustable in order to impart a selective tensile force on the display screen 1220 and / or the display unit housing 1205 in order to secure a position of the display screen 1220 and / or the display unit housing 1205.

[0306] In certain forms, the display unit housing 1205 and / or the forehead support 1360 (as the case may be) may include at least one loop or eyelet 1254, and the top strap portion may be threaded through that eyelet 1254, and doubled back on itself. The length of the top strap portion threaded through the eyelet 1254 may be selected by the user in order to adjust the tensile force provided by the positioning and stabilizing structure 1300. For example, threading a greater length of the top strap portion through the eyelet 1254 may supply a greater tensile force.

[0307] In some forms, the top strap portion may include an adjustment portion and a receiving portion. The adjustment portion may be positioned through the eyelet 1254, and may be coupled to the receiving portion (e.g., by doubling back on itself). The adjustment portion may include a hook material, and the receiving portion may include a loop material (or vice versa), so that the adjustment portion may be removably held in the desired position. In some examples, the hook material and the loop material may be Velcro.5.2.2.5 Rotational Control

[0308] In some forms, the display unit housing 1205 and / or the display screen 1220 may pivot relative to the user’s face while the user has donned the positioning and stabilizing structure. This may allow the user to see the physical environment while still wearing the user interface 1100. This may be useful for users who want to take a break for viewing the virtual environment, but do not wish to doff the positioning and stabilizing structure 1300.

[0309] In some forms, a pivot connection 1260 may be formed between a superior portion of the display unit housing 1205 and the positioning and stabilizing structure 1300. For example, the pivot connection 1260 may be formed on the superior face 1230 of the display unit housing 1205.

[0310] In certain forms, the pivot connection 1260 may be coupled to the forehead support 1360. The display unit housing 1205 may be able to pivot about an inferior edge of the forehead support 1360.

[0311] In one form, the temporal connectors 1250 may be coupled to the forehead support 1360 in order to allow the display unit housing 1205 to pivot.

[0312] In some forms, the pivot connection 1260 may be a ratchet connection, and may maintain the display unit housing 1205 in a raised position without additional user intervention.5.2.3 Controller

[0313] As shown in Fig. 6, some forms of the head-mounted display system 1000 include a controller 1270 that can be engageable by the user in order to provide user input to the virtual environment and / or to control the operation of the head-mounted display system 1000. The controller 1270 can be connected to the head-mounted display unit 1200, and provide the user the ability to interact with virtual objects output to the user from the head-mounted display unit 1200.5.2.3.1 Handheld Controller

[0314] In some forms, the controller 1270 may include a handheld device, and may be easily grasped by a user with a single hand.

[0315] In certain forms, the head-mounted display system 1000 may include two handheld controllers. The handheld controllers may be substantially identical to one another, and each handheld controller may be actuatable by a respective one of the user’s hands.

[0316] In some forms, the user may interact with the handheld controller(s) in order to control and / or interact with virtual objects in the virtual environment.

[0317] In some forms, the handheld controller includes a button that may be actuatable by the user. For example, the user’s fingers may be able to press the button while grasping the handheld controller.

[0318] In some forms, the handheld controller may include a directional control (e.g., a joystick, a control pad, etc.). The user’s thumb may be able to engage the directional control while grasping the handheld controller.

[0319] In certain forms, the controller 1270 may be wirelessly connected to the head-mounted display unit 1200. For example, the controller 1270 and the headmounted display unit 1200 may be connected via Bluetooth, Wi-Fi, or any similar means.

[0320] In certain forms, the controller 1270 and the head-mounted display unit 1200 may be connected with a wired connection.5.2.3.2 Fixed Controller

[0321] In some forms, at least a portion of the controller 1270 may be integrally formed on the display unit housing 1205.

[0322] In some forms, the controller 1270 may include control buttons that are integrally formed on the display unit housing 1205. For example, the control buttons may be formed on the superior face 1230 and / or the inferior face 1232, so as to be engageable by the user’s fingers when holding the user’s palm rests against the lateral left or right face 1234, 1236 of the display unit housing 1205. Control buttons may also be disposed on other faces of the display unit housing 1205.

[0323] In some forms, the user may interact with the control buttons in order to control at least one operation of the head-mounted display system 1000. For example, the control button may be an On / Off button, which may selectively control whether the display screen 1220 is outputting an image to the user.

[0324] In certain forms, the control buttons and the head-mounted display unit 1200 may be connected with a wired connection.

[0325] In some forms, the head-mounted display system 1000 may include both the handheld controller and the control buttons.5.2.4 Speaker

[0326] With reference to Fig. 6, in some forms the head-mounted display system 1000 includes a sound system or speakers 1272 that may be connected to the headmounted display unit 1200 and positionable proximate to the user’s ears in order to provide the user with an auditory output.

[0327] In some forms, the speakers 1272 may be positionable around the user’s ears, and may block or limit the user from hearing ambient noise.

[0328] In certain forms, the speakers 1272 may be wirelessly connected to the head-mounted display unit 1200. For example, the speakers 1272 and the headmounted display unit 1200 may be connected via Bluetooth, Wi-Fi, or any similar means.

[0329] In some forms, the speaker 1272 includes a left ear transducer and a right ear transducer. In some forms, the left and right ear transducers may output different signals, so that the volume and or noise heard by the user in one ear (e.g., the left ear) may be different than the volume and or noise heard by the user in the other ear (e.g., the right ear).

[0330] In some forms, the speaker 1272 (e.g., the volume of the speaker 1272) may be controlled using the controller 1270.5.2.5 Power Source

[0331] With reference to Fig. 6, some forms of the head-mounted display system 1000 may include an electrical power source 1274 can provide electrical power to the head-mounted display unit 1200 and any other electrical components of the headmounted display system 1000.

[0332] In certain forms, the power source 1274 may include a wired electrical connection that may be coupled to an external power source, which may be fixed to a particular location.

[0333] In certain forms, the power source 1274 may include a portable battery that may provide power to the head-mounted display unit 1200. The portable battery may allow the user greater mobility than compared to a wired electrical connection.

[0334] In certain forms, the head-mounted display system 1000 and / or other electronic components of the head-mounted display system 1000 may include internal batteries, and may be usable without the power source 1274.

[0335] In some forms, the head-mounted display system 1000 may include the power source 1274 in a position remote from the head-mounted display unit 1200. Electrical wires may extend from the distal location to the display unit housing 1205 in order to electrically connect the power source 1274 to the head-mounted display unit 1200.

[0336] In certain forms, the power source 1274 may be coupled to the positioning and stabilizing structure 1300. For example, the power source 1274 may be coupled to a strap of the positioning and stabilizing structure 1300, either permanently or removably. The power supply 1274 may be coupled to a posterior portion of the positioning and stabilizing structure 1300, so that it may be generally opposite the display unit housing 1205 and / or the head-mounted display unit 1200. The weight of the power source 1274, and the weight of the head-mounted display unit 1200 and the display unit housing 1205 may therefore be spread throughout the head-mounted display system 1000, instead of concentrated at the anterior portion of the headmounted display system 1000. Shifting weight to the posterior portion of the headmounted display system 1000 may limit the moment created at the user’s face, which may improve comfort and allow the user to wear the head-mounted display system 1000 for longer periods of time.

[0337] In certain forms, the power source 1274 may be supported by a user distal to the user’s head. For example, the power source 1274 may connected to the headmounted display unit 1200 and / or the display unit housing 1205 only through an electrical connector (e.g., a wire). The power source 1274 may be stored in the user’s pants pocket, on a belt clip, or a similar way which supports the weight of the power source 1274. This removes weight that the user’s head is required to support, and may make wearing the head-mounted display system 1000 more comfortable for the user.

[0338] In some forms, the head-mounted display unit 1200 may include the power source 1274. For example, the display unit 1220 may be a cell phone, or other similar electronic device, which includes an internal power source 1274.5.2.6 Control System

[0339] With reference to Fig. 6, some forms of the head-mounted display system 1000 include a control system 1276 that assists in controlling the output received by the user. Specifically, the control system 1276 can control visual output from the display screen 1220 and / or auditory output from the speakers 1272.

[0340] In some forms, the control system 1276 may include sensors that monitor different parameters (e.g., in the physical environment), and communicates measured parameters to a processor. The output received by the user may be affected by the measured parameters.

[0341] In some forms, the control system 1276 is integrated into the headmounted display unit 1200. In other forms, the control system 1276 is housed in a control system support 1290 that is separate from, but connected to (e.g., electrically connected to) the head-mounted display unit 1200.5.2.6.1 Power Source

[0342] In some forms, the control system 1276 may be powered by the power source 1274, which may be at least one battery used for powering components of the control system 1276. For example, sensors of the control system 1276 may be powered by the power source 1274.

[0343] In some forms, the at least one battery of the power source 1274 may be a low power system battery 1278 and a main battery 1280.

[0344] In certain forms, the low power system battery 1278 may be used to power a real time (RT) clock 1282 of the control system 1276.5.2.6.1.1 Integrated Power Support Portion

[0345] In some forms, a battery support portion 1288 may support the low power system battery 1278 and / or the main battery 1280. The battery support portion 1288 may be directly supported on the head-mounted display system 1000.

[0346] In some forms, the battery support portion 1288 may be disposed within the display unit housing 1205.

[0347] In some forms, the battery support portion 1288 may be disposed on the positioning and stabilizing structure 1300. For example, the battery support portion 1288 may be coupled to the posterior support portion 1350. The weight of the headmounted display system 1000 may be better balanced around the user’s head. One form of a battery support portion 1288 is a battery pack housing, which will be described in more detail herein.5.2.6.1.2 Remote Power Support Portion

[0348] In some forms, a battery support portion 1288 may support the low power system battery 1278 and / or the main battery 1280. The battery support portion 1288 may be coupled to the user independently of the positioning and stabilizing structure 1300 and / or the display unit housing 1205 (e.g., it may be coupled via a belt clip). The battery support portion 1288 also may be supported remote from the user’s body (e.g., if the head-mounted display system 1000 receives power from a computer or video game console). A tether may couple the battery support portion 1288 to the control system 1276 and / or other electronics. The positioning of the battery support portion may improve comfort for the user, since the weight of the low power system battery 1278 and / or the main battery 1280 are not supported by the user’s head.5.2.6.2 Orientation Sensor

[0349] In some forms, the control system 1276 includes an orientation sensor 1284 that can sense the orientation of the user’s body. For example, the orientation sensor 1284 may sense when the user rotates their body as a whole, and / or their head individually. In other words, the orientation sensor 1284 may measure an angular position (or any similar parameter) of the user’s body. By sensing the rotation, the sensor 1284 may communicate to the display screen 1220 to output a different image.

[0350] In some examples, an external orientation sensor may be positioned in the physical environment where the user is wearing the head-mounted display system 1000. The external position sensor may track the user’s movements similar to the orientation sensor 1284 described above. Using an external orientation sensor may reduce the weight required to be supported by the user.5.2.6.2.1 Camera

[0351] In some forms, the control system 1276 may include at least one camera, which may be positioned to view the physical environment of the user.

[0352] In some forms, the orientation sensor 1284 is a camera, which may be configured to observe the user’s physical environment in order to determine the orientation of the user’s head (e.g., in what direction the user’s head has tilted).

[0353] In some forms, the orientation sensor 1284 includes multiple cameras positioned throughout the head-mounted display system 1000 in order to provide a more complete view of the user’s physical environment, and more accurately measure the orientation of the user’s head.

[0354] In some forms, the cameras 1284 are coupled to the anterior face 1238 of the display unit housing 1205. The cameras 1284 may be positioned in order to in order to provide a “first-person” view.

[0355] In certain forms, the display screen 1220 may display the user’s physical environment by using the cameras 1284, so that the user may feel as though they are viewing their physical environment without assistance from the head-mounted display system 1000 (i.e., the first person view). This may allow the user to move around their physical environment without removing the head-mounted display system 1000.

[0356] In one form, virtual objects may be displayed while the display screen 1220 is displaying the user’s physical environment. The cameras 1284 may allow the head-mounted display system 1000 to operate as an MR device. The control system 1276 may include a control to switch operation between a VR device and an MR device.5.2.6.3 Eye Sensor

[0357] In some forms, the control system 1276 may include an eye sensor that can track movement of the user’s eyes. For example, the eye sensor may be able to measure a position of at least one of the user’s eyes, and determine which direction at least one of the user’s eyes are looking.

[0358] In some forms, the control system 1276 may include two eye sensors.Each sensor may correspond to one of the user’s eyes.

[0359] In some forms, the eye sensors may be disposed in or proximate to the lenses 1240.

[0360] In some forms, the eye sensors may measure an angular position of the user’s ears in order to determine the visual output from the display screen 1220.5.2.6.4 Processing System

[0361] In some forms, the control system 1276 includes a processing system that may receive the measurements from the various sensors of the control system 1276.

[0362] In some forms, the processing system may receive measurements recorded by the orientation sensor 1284 and / or the eye sensors. Based on these measured values, the processor can communicate with the display screen 1220 in order to change the image being output. For example, if the user’s eyes and / or the user’s head pivots in the superior direction, the display screen 1220 may display a more superior portion of the virtual environment (e.g., in response to direction from the processing system).5.3 AUGMENTED REALITY DISPLAY INTERFACE

[0363] As shown in Figs. 5A and 5B, a display apparatus or head-mounted display system 1000 in accordance with one aspect of the present technology comprises the following functional aspects: a display screen 1220 configured for augmented reality, a display unit housing 1205, and a positioning and stabilizing structure 1300. In some forms, a functional aspect may provide one or more physical components. In some forms, one or more physical components may provide one or more functional aspects. In use, the display screen 1220 is arranged to be positioned proximate and anterior to the user’s eyes, so as to allow the user to view the display screen 1220.

[0364] In other aspects, the head-mounted display system 1000 may also include an interfacing structure 1100, a controller 1270, a speaker 1272, a power source 1274, and / or a control system 1276. In some examples, these may be integral pieces of thehead-mounted display system 1000, while in other examples, these may be modular and incorporated into the head-mounted display system 1000 as desired by the user.5.4 POSITIONING AND STABILISING STRUCTURES

[0365] Figs. 7A-7O show positioning and stabilising structures 1300 and headmounted display systems 1000 comprising positioning and stabilising structures 1300. The positioning and stabilising structures 1300 disclosed herein may be constructed and arranged in particular for use in head-mounted display systems 1000 for use in VR, MR or AR, for example. It is to be understood that the positioning and stabilising structures 1300 and head-mounted display systems 1000 described herein, or individual features thereof, may be applied in any of VR, MR, AR or other artificial reality. The head-mounted display system 1000 may otherwise have any of the features, configurations, aspects, functions and the like as described elsewhere herein.

[0366] The head-mounted display systems 1000 according to examples of the present technology, such as those that are described with reference to Figs. 7A-7O, may comprise a head-mounted display unit 1200 comprising a display unit housing 1205. The display unit housing 1205 may comprise a display. The display may be as described elsewhere herein or as known in the art. The head-mounted display unit 1200 may comprise an interfacing structure 1100 connected to the display unit housing 1205 and constructed and arranged to engage the user’s face in use.

[0367] Positioning and stabilising structures 1300 according to examples of the present technology, such as those that are shown in Figs. 7A-7O are constructed and arranged to hold the head-mounted display unit 1200 in an operable position on the user’s head in use (e.g., such that the display is positioned in a viewing position anterior to the user’s eyes and such that the interfacing structure 1100 engages the user’s face to form a light seal, such as at least in forehead, sphenoid and cheek regions of the user’s face).

[0368] The interfacing structure 1100 may be configured to engage the user’s face around a periphery of the user’s eyes in use. The interfacing structure 1100 may be configured to engage the sides of the user’s face lateral of the user’s eyes and engage the user’s forehead in use. In some examples the interfacing structure 1100 may engage the user’s cheeks, the sides of the user’s face lateral of the user’s eyesand the user’s forehead. In some forms, the interfacing structure 1100 may engage the user’s face at regions overlying the user’s nose, maxilla, zygomatic bones, sphenoid bones and frontal bones. The interfacing structure 1100 may engage the user’s face in regions shown in Fig. 4D, for example.

[0369] In some examples, the interfacing structure 1100 may comprise a face engaging flange, membrane, flap or the like (not shown) structured and arranged to be provided around a periphery of an eye region of the user’s face and configured to engage the user’s face in use. The face engaging flange may be flexible and resilient. In some examples, the face engaging flange is formed from an elastomeric material, for example silicone or TPE. In some examples the interfacing structure 1100 comprises a cushion (not visible in the drawings). The cushion may be at least partially covered by the face engaging flange. The cushion may be formed from foam, silicone, gel or another suitable cushion material or structure constructed to behave as a cushion. In some examples, the interfacing structure 1100 comprises a cushion but no face engaging flange.

[0370] The interfacing structure 1100 may be configured to engage the user’s face and resist compression when the head-mounted display unit 1200 is fastened securely to the user’s face, while remaining comfortable to the user. The cushion (if present) may contribute to the resilience of the interfacing structure 1100. The interfacing structure 1100 may comprise a pair of cheek portions 1140 configured to engage the user’s cheeks in use, a forehead portion 1175 configured to engage the user’s forehead in use, and a pair of sphenoid portions 1170 located on respective lateral sides of the interfacing structure connecting between the forehead portion and the cheek portions and configured to engage the user’s head proximate the sphenoid bone.

[0371] In some examples, the interfacing structure 1100 comprises a nasal portion 1180 between the cheek portions 1140, as shown in Fig. 4. The nasal portion 1180 may be configured to engage the user’s nose in use and may be configured to at least partially block light from reaching the user’s eyes from the user’s nose region (e.g., block light travelling via a path proximate the surfaces of the user’s nose). The nasal portion 1180 may for example be configured to engage anterior, superior and / orlateral surfaces of the user’s nose in use. The nasal portion 1180 may be attached to the cheek portions 1140.

[0372] In some examples, such as the examples shown in Figs. 7A-7O the headmounted display system 1000 comprises a pair of arms 1210 connected in use (e.g., fixedly attached or removably connected) to respective lateral sides of the display unit housing 1205 (e.g., to the housing and / or a pair of lateral support arms on the housing). The arms 1210 may be constructed and arranged to project posteriorly from the display unit housing 1205 on respective lateral sides of the user’s head in use. Anterior portions of the arms 1210 may include a connector (e.g., snap-fit connector, pin connection or the like) to facilitate removeable connection to the display unit housing 1205. In other examples the arms 1210 may not be separable from the display unit housing 1205.

[0373] The arms 1210 may be configured to resist bending about one or more axes and may therefore be described as rigidised or at least semi-rigid (i.e., semi-rigid or rigid). Rigidised portions of a positioning and stabilising structure 1300 or strap thereof may be rigidised if they are stiffened so as to be able to transfer forces other than tension to another portion of the positioning and stabilising structure 1300 or strap thereof, for example by providing resistance to bending or compression forces. The arms 1210 may comprise a textile outer layer and may be rigidised to be substantially rigid. In some examples the arms 1210 may comprise a substantially rigid component covered in a textile layer (e.g., textile on both sides or textile on one side). In some examples only a user-facing side of the arms 1210 comprises a textile layer.

[0374] In some examples each arm 1210 is at least partially covered by a textile sleeve. In some particular examples each arm 1210 is encapsulated within a textile sleeve. Partially or fully covering the arms 1210 may provide for comfortable contact between the arm 1210 and the user’s head, may be aesthetically pleasing, may provide for a perception of comfort and may conceal or protect other components provided to the arms 1210, such as electronics, sensors, transducers or the like, or wiring running along an arm 1210 to a posterior battery pack or any other components.

[0375] The arms 1210 may be pivotably attached to the display unit housing 1205, which may advantageously allow the angle of head-mounted display unit 1200 to be adjusted to suit the user’s particular anatomy. Rigidised parietal strap portion connected to arms

[0376] Figs. 7A-7D show examples of head-mounted display systems 1000. In each of these examples the head-mounted display system 1000 comprises a positioning and stabilising structure 1300 comprising a pair of arms 1210. The arms 1210 may be attached in use to a display unit housing 1205 on respective sides thereof. As illustrated, the arms 1210 extend posteriorly from the display unit housing 1205.

[0377] The positioning and stabilising structure 1300 in each of these examples also comprises a parietal strap portion 1310 configured to engage the user’s head at a region overlying the parietal bones of the user’s head in use. As illustrated, the parietal strap portion 1310 is connected to each of the pair of arms 1210 in these examples. The parietal strap portion 1310 may be rigidised, e.g. it may be semi-rigid to resist bending in superior-inferior directions in use. The parietal strap portion 1310 may also resist extension along its length (although may be selectively adjustable in length by the user).

[0378] The arms 1210 and parietal strap portion 1310 may together with the head-mounted display unit 1200 form a rigidised loop encircling the lateral sides and posterior of the user’s head. The arms 1210 and parietal strap portion 1310 may resist superior and inferior bending and resist tension, to support at least some of the weight of the head-mounted display unit 1200 and to hold it securely on the user’s head. However, the parietal strap portion 1310 may be constructed to be able to wrap comfortably around the user’s head in use. The parietal strap portion 1310 may for example have a thin cross section, and may be formed from a material that allows for medial / lateral bending.

[0379] In some forms of the present technology, the parietal strap portion 1310 comprises a predetermined shape whereby, on each lateral side of the user’s head, the parietal strap portion 1310 curves superiorly away from each of the arms 1210. Advantageously, this enables the parietal strap portion 1310 to engage a partiallysuperior-facing surface region of the user’s head, instead of engaging a surface region behind the user’s head that faces only a substantially posterior direction. This may provide for good comfort when the user lies down facing up, as the bulk of the parietal strap portion 1310 is at least partially out of the way of the centre of the posterior of the user’s head. Additionally, or alternatively, this may provide for good stability when the user lies down facing up, as less force from the pillow or surface on which the user is lying may be applied to the parietal strap portion 1310. Such forces could otherwise be transferred through to the arms 1210 and to the head-mounted display unit 1200, tending to force it out of engagement with the user’s face.

[0380] In the illustrated examples in Figs. 7A-7D, the parietal strap portion 1310 comprises a pair of anterior portions 1311 each connected to a respective one of the pair of arms 1210, and a posterior portion 1312 connected to the anterior portions 1311 and configured to engage the region overlying the parietal bones of the user’s head. The posterior portion 1312 of the parietal strap portion 1310 may be formed at least partially from foam. In other examples the parietal strap portion 1310 may be formed at least partially from an elastomeric material such as silicone, TPE or the like. In some examples the posterior portion 1312 of the parietal strap portion 1310 comprises a textile covering.

[0381] In the illustrated examples, the posterior portion 1312 of the parietal strap portion 1310 is constructed to have a predetermined curved shape. The posterior portion 1312 of the parietal strap portion 1310 may be dome shaped. Advantageously, a dome shape, e.g. curvature in two orthogonal directions to at least partially correspond to the shape of the user’s head, may provide for good engagement of the parietal strap portion 1310 to the user’s head. In particular, in comparison to a strap that is curved in only one direction, or not curved at all, a dome shape may spread the force between the strap and the user’s head out more evenly over the entire area of the strap. In the illustrated examples, the posterior portion 1312 of the parietal strap portion 1310 is wider in a medial portion thereof than at lateral ends thereof.

[0382] The parietal strap portion 1310 may be adjustable in length. In some examples, one or both of the anterior portions 1311 are moveable with respect to the posterior portion 1312 to adjust the length of the parietal strap portion 1310. For example, one or both of the anterior portions 1311 may be able to slide in the lengthdirection of the posterior portion 1312 to extend from or retract into the posterior portion 1312. In some examples the extension / retraction is controlled by the user pushing / pulling the portions together or apart between indexed positions. In other examples a dial adjustment mechanism 1390 as shown in Fig. 7A is provided to the parietal strap portion 1310.

[0383] In some examples the parietal strap portion 1310 comprises one or more counterweights 1386. In the example shown in Fig. 7B, the parietal strap portion 1310 comprises a pair of counterweights 1386, each spaced from and located on opposing sides of the mid-sagittal plane of the user’s head in use. Advantageously, providing two counterweights 1386 to both sides of the parietal strap portion 1310 may result in better stability than one larger counterweight 1386 centrally as the head-mounted display system 1000 may be less likely to wobble due to inertia during side movements. The parietal strap portion 1310 is an advantageous location for the counterweights 1386 as the counterweights 1386 are able to be spaced as far back as possible, allowing for less weight overall to achieve a particular counterbalancing moment to the head-mounted display system 1000.

[0384] The positioning and stabilising structure 1300 may comprise a frontal strap portion 1394 constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head. Advantageously, the frontal strap portion 1394 and the parietal strap portion 1310 may be spaced apart in the anterior- posterior directions by a spacing less than the anterior-posterior length of the user’s head. This means that together they fit to and engage partially superior-facing surfaces of the user’s head, so as support some, or most, of the weight of the headmounted display system 1000. Other systems relying on a single strap engaging a posterior-facing surface of the user’s head may rely predominantly on the strap and display unit “clamping” the user’s head, which may require greater forces on the user’s head and therefore may be uncomfortable and / or cause facial marking.

[0385] In the examples shown in Figs. 7A-7D, the positioning and stabilising structure 1300 comprises a band strap portion 1380 constructed and arranged to encircle the user’s head in use. The band strap portion 1380 may overlie the user’s forehead, and may form an occipital strap portion 1320 constructed and arranged toengage a region of the user’s head overlying or lying inferior to the occipital bone in use.

[0386] The band strap portion 1380 may be elastically extendable in length. For example, the band strap portion 1380 may be formed from an elastic material, such as an elastic textile material. In some examples, the band strap portion 1380 has an unextended length which is selectively adjustable by the user, for example by an adjustable buckle or an eyelet combined with a hook and loop fastening connection. The band strap portion 1380 may be selectively adjustable in length by the user and then, after adjustment, may also be elastically extendable in response to tension.

[0387] In some examples, the band strap portion 1380 comprises an occipital pad positioned in use to engage the region of the user’s head overlying or lying inferior to the occipital bone. The occipital pad may be formed by, as examples, an elastomeric material (e.g. silicone or TPE), foam, and / or a textile material. In some examples, the occipital pad has a textile outer layer.

[0388] In the examples shown in Figs. 7A-7D, lateral portions of the band strap portion 1380 are held apart from each other by the parietal strap portion 1310 prior to donning of the head-mounted display system 1000 by the user. The parietal strap portion 1310 and the arms 1210 to which it is attached may be rigidised and therefore hold a laterally spaced-out shape, which may in turn hold the lateral portions of the band strap portion 1380 apart from each other. This may provide for good usability as the band strap portion 1380 is held in an open configuration ready to fit over the user’s head. The band strap portion 1380 may pass between two layers of the parietal strap portion 1310 on each lateral side of the user’s head in use.

[0389] The frontal strap portion 1394 in some examples comprises a forehead pad 1395 configured to engage the user’s forehead, as shown in Figs. 7A-7D. In various examples, the forehead pad 1395 may formed from one or more of an elastomeric material (e.g. silicone, TPE or the like), foam and / or a textile material. The forehead pad 1395 may comprise an elastomeric user-contacting surface, which may advantageously provide for high friction between the forehead pad 1395 and the user’s forehead, to help support weight of the head-mounted display unit 1200. In other example, the forehead pad 1395 may comprise an inner foam portion, whichmay provide compliance and cushioning, and a textile outer layer, which may provide a comfortable feel on the user’s face and an aesthetically pleasing appearance.

[0390] In some examples, the forehead pad 1395 is provided to the band strap portion 1380, as shown in Figs. 7B-7D. In other examples the forehead pad 1395 is attached to the head-mounted display unit 1200 and the band strap portion 1380 overlies the forehead pad 1395 or engages the user’s forehead superior to the forehead pad 1395. As shown in Fig. 7A, the band strap portion 1380 overlies the forehead pad 1395. Advantageously, this may help achieve good engagement between the forehead pad 1395 and the forehead.

[0391] In some examples, forehead pad 1395 comprises a frame and a cushion attached to the frame. The frame of the forehead pad 1395 may be attached to the head-mounted display unit 1200. In such examples the forehead pad 1395 may support or suspend the display unit housing 1205 anterior to the user’s face in use and the head-mounted display unit 1200 may not engage the user’s face around a periphery of the user’s eye region, allowing the user to maintain some sight of their surroundings through peripheral vision. This configuration is shown in Fig. 7A. The forehead pad 1395 may form the interfacing structure 1100 in this configuration.

[0392] In other examples, such as those shown in Figs. 7B-7E, the head-mounted display system 1000 comprises an interfacing structure 1100 connected to the display unit housing and constructed and arranged to engage the user’s face in use around a periphery of the user’s eye region. The interfacing structure 1100 may be constructed and arranged to engage sphenoid regions, cheek regions and the forehead region of the user’s face.

[0393] In the example shown in Fig. 7B, the head-mounted display system 1000 comprises a frontal connector 1345 constructed and arranged to connect between the frontal strap portion 1394 of the positioning and stabilising structure 1300 and each of the arms 1210 to support at least some weight of the head-mounted display unit 1200 in use via the arms 1210. The frontal connector 1345 may be particularly advantageous when the head-mounted display unit 1200 does not otherwise have any dedicated means for connection to straps at a medial and superior location of the user’s forehead in use. The frontal connector 1345 may comprise a pair of lateralportions each extending towards and attaching to a respective one of the arms 1210. The frontal connector 1345 may be attached to a forwardmost portion of the each of the arms 1210. Advantageously, this may avoid the frontal connector 1345 urging the arms 1210 medially into uncomfortable contact with the user’s face, or at least reduce the severity of such an effect. The frontal connector 1345 may be Y-shaped, wishbone shaped or the like.

[0394] In the example shown in Fig. 7C, the positioning and stabilising structure 1300 comprises a top strap portion 1340 constructed and arranged to engage superior surfaces of the user’s head and connecting between the parietal strap portion 1310 and the frontal strap portion 1394 of the positioning and stabilising structure 1300 and / or the head-mounted display unit 1200. In the example shown in Fig. 7C, the top strap portion 1340 is constructed and arranged to connect between the parietal strap portion 1310 and the band strap portion 1380. The top strap portion 1340 may be substantially aligned with the user’s mid-sagittal plane. The top strap portion 1340 may connect to the parietal strap portion 1310 and frontal strap portion 1394 or head-mounted display unit 1200 by magnetic, buckle, hook and loop, or sewn connections, by way of examples only.

[0395] In some examples, the parietal strap portion 1310 is connected to the occipital strap portion 1320. As shown in Fig. 7D for example, the positioning and stabilising structure 1300 comprises a posterior support portion 1350 engaging the user’s head in the region overlying the parietal bones and in the region overlying or lying inferior to the occipital bone. In this example, the parietal strap portion 1310 partially forms the posterior support portion 1350. The posterior support portion 1350 may be connected to the occipital strap portion 1320. For example, the occipital strap portion 1320 may be connected to the posterior support portion 1350 by passing through one or more guides provided to the posterior support portion 1350. The posterior support portion 1350 may be annular in shape.

[0396] In various example, the posterior support portion 1350 may be formed from foam and / or textile materials. In some examples, the posterior support portion 1350 comprises an inner foam layer a textile outer layer. In some examples, the posterior support portion is thermoformed. The posterior support portion 1350 may be constructed to have a predetermined curved shape. As one example, thepredetermined curved shape of the posterior support portion 1350 comprises curvature in two orthogonal directions. Advantageously, this may provide for good engagement with the user’s head and may provide for even distribution of force.

[0397] In some examples, such as is shown in Fig. 7D, the posterior support portion 1350 comprises a superior portion and an inferior portion separated by a hinge region 1314 on each side of the posterior support portion 1350, each hinge region constructed and arranged to encourage bending to occur at the hinge region (e.g. instead of elsewhere in the posterior support portion 1350). This controlled bending at the hinge region 1314 may advantageously facilitate good engagement of the posterior support portion 1350 with complex curvature of the user’s head. In some examples, the hinge region 1314 may be constructed to have greater extensibility than the superior portion and the inferior portion of the posterior support portion 1350.This may advantageously, allow the posterior support portion 1350 to accommodate a wide range of head shapes and sizes. The superior portion of the posterior support portion 1350 may at least partially form the parietal strap portion 1310 and the inferior portion of the posterior support portion 1350 may at least partially form the occipital strap portion 1320. The hinge regions 1314 may be formed by thermoforming, e.g. the hinge regions 1314 may be thermoformed details in the posterior support portion 1350. For example, the hinge regions 1314 may be formed thinner, by thermoforming, than the adjacent portions of the posterior support portion 1350, to provide greater flexibility at the hinge regions 1314. Alternatively, sewing may be used to create a seam along which the posterior support portion 1350 may tend to bend.

[0398] In some examples, one or more portions of the positioning and stabilising structure 1300 may house a cable, such as a power cable, earphone cable or the like. In some examples, the parietal strap portion 1310 comprises a cable routed therethrough. The cable may be routed between two layers of the parietal strap portion 1310. In other examples, the band strap portion 1380 comprises a cable routed therethrough. The cable may be routed between two layers of the band strap portion 1380.5.4.1 Rigidised occipital strap portion connected to arms

[0399] Fig. 7E shows a head-mounted display system 1000 according to a further example of the present technology. The head-mounted display system 1000 may comprise a head-mounted display unit 1200 comprising a display unit housing 1205, and may further comprise an interfacing structure 1100, all as described elsewhere. The head-mounted display system 1000 may further comprise a positioning and stabilising structure 1300 constructed and arranged to hold the head-mounted display unit 1200 in an operable position on the user’s head in use. The positioning and stabilising structure 1300 may comprise a pair of arms 1210 attached in use to the display unit housing 1205 on respective sides thereof. The arms 1210 may extend posteriorly from the display unit housing 1205. There are various similarities between the example shown in Fig. 7E and any of the examples shown in Figs. 7A-7D and Figs. 7F-7O. Not all of these similarities or shared features will be repeated in the description of the example shown in Fig. 7E. The features described with reference to one example are to be understood to be applicable to any other example, unless context requires otherwise.

[0400] In the example shown in Fig. 7E, the positioning and stabilising structure 1300 comprises a band strap portion 1380 constructed and arranged to encircle the user’s head in use. The band strap portion 1380 may be connected to each of the pair of arms 1210 in use. In this example, the band strap portion 1380 forms a frontal strap portion 1394 and an occipital strap portion 1320. The frontal strap portion 1394 may be constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head. The occipital strap portion 1320 may be configured to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use.

[0401] In the Fig. 7E example, the positioning and stabilising structure 1300 further comprises a pair of rigidisers 1323 provided to respective lateral sides of the occipital strap portion 1320. Each rigidiser 1323 may be fixedly connected to a respective one of the pair of arms 1210 in use. That is, the rigidisers 1323 may be unable to rotate with respect to the arms 1210. This may advantageously allow at least some of the weight of the head-mounted display unit 1200 to be transferred to and supported by the posterior of the user’s head.

[0402] As shown in Fig. 7E, each of the rigidisers 1323 curves inferiorly away from the respective arm 1210 in this example. Each of the rigidisers 1323 also comprises a posterior end. The rigidisers 1323 in this particular example do not connect to each other posterior to the user’s head. Each of the rigidisers 1323 may curve medially proximate the respective posterior end. This may advantageously assist in transferring some of the weight of the head-mounted display unit 1200 to the posterior surfaces of the user’s head and may also advantageously, help resist riding up of the occipital strap portion 1320 in use, as the rigidisers 1323 curve medially into good engagement with partially inferior-facing surfaces of the posterior of the user’s head. The respective posterior ends of the rigidisers 1323 may be spaced apart in use. This may leave an unrigidised portion between the rigidisers 1323 which may help with donning the head-mounted display system 1000 and / or allow for length adjustability of the occipital strap portion 1320.

[0403] Each rigidiser 1323 may be provided internally to the occipital strap portion 1320. In some examples, the occipital strap portion 1320 is formed at least partially from foam. The occipital strap portion 1320 may comprise one or more textile outer layers. In some examples the thickness of the occipital strap portion 1320, formed mostly by the thickness of the foam, may be 8mm.

[0404] The occipital strap portion 1320 may be adjustable in length. In the example shown in Fig. 7E, the occipital strap portion 1320 comprises a pair of anterior portions 1324 located on respective lateral sides of the user’s head in use and a posterior portion 1325 connecting the anterior portions 1324 of the occipital strap portion 1320. In this example, the posterior portion 1325 of the occipital strap portion 1320 comprises an unextended length that is selectively adjustable, for example by being connected to one or both of the anterior portions 1324 by buckles allowing for length adjustment of the posterior portion 1325. In this example, the posterior portion 1325 is elastically extendable, which may facilitate easy donning and doffing. In this example the anterior portions 1324 of the occipital strap portion 1320 may have a thickness of 8mm. The posterior portion 1325 of the occipital strap portion 1320 may be thinner and / or more elastically extendable than the anterior portions 1324 and may have a thickness of 4mm.

[0405] In the example shown in Fig. 7E, the positioning and stabilising structure 1300 further comprises a parietal strap portion 1310 constructed and arranged to engage the user’s head in use in a region overlying the parietal bones of the user’s head. The parietal strap portion 1310 is connected to the band strap portion 1380 in this example.

[0406] In some examples, the parietal strap portion 1310 is formed at least partially from foam. The parietal strap portion 1310 may comprise one or more textile outer layers. In some examples the thickness of the parietal strap portion 1310, formed mostly by the thickness of the foam, may be 8mm.

[0407] The parietal strap portion 1310 may be adjustable in length. In the example shown in Fig. 7E, the parietal strap portion 1310 comprises a pair of anterior portions 1311 located on respective lateral sides of the user’s head in use and a posterior portion 1312 connecting the anterior portions 1311 of the parietal strap portion 1310. In this example, the posterior portion 1312 of the parietal strap portion 1310 comprises an unextended length that is selectively adjustable, for example by being connected to one or both of the anterior portions 1311 by buckles allowing for length adjustment of the posterior portion 1312. In this example, the posterior portion 1312 is elastically extendable, which may facilitate easy donning and doffing. In this example the anterior portions 1311 of the parietal strap portion 1310 may have a thickness of 8mm. The posterior portion 1312 of the parietal strap portion 1310 may be thinner and / or more elastically extendable than the anterior portions 1311 and may have a thickness of 4mm.

[0408] Length adjustment of the parietal strap portion 1310 and / or occipital strap portion 1320 may advantageously allow the positioning and stabilising structure 1300 to fit a wide range of head shapes and sizes well (e.g. comfortably and securely).

[0409] In some examples, the frontal strap portion 1394 of the positioning and stabilising structure 1300 is connected the head-mounted display unit 1200 in use to support at least some weight of the head-mounted display unit 1200. As shown in Fig. 7E the frontal strap portion 1394 of the positioning and stabilising structure 1300 is connected to the head-mounted display unit 1200 by a frontal connector 1345. In thisexample the frontal connector 1345 comprises a strap portion connected directly to the head-mounted display unit 1200, for example to the display unit housing 1205.

[0410] In other examples, the frontal connector 1345 may be constructed and arranged to connect between the frontal strap portion 1394 of the positioning and stabilising structure 1300 and each of the arms 1210 to support at least some weight of the head-mounted display unit 1205 in use via the arms 1210. This type of frontal connector 1345 is described herein with reference to Fig. 7B.

[0411] In other examples, there may be no frontal connector 1345.

[0412] In the example shown in Fig. 7E, each anterior portion 1324 of the occipital strap portion 1320 is integrally formed with a respective one of the anterior portions 1311 of the parietal strap portion 1310. Also in this example, each anterior portion 1324 of the occipital strap portion 1320 is integrally formed with the frontal strap portion 1394. That is, in the Fig. 7E example, the frontal strap portion 1394, the anterior portions 1324 of the occipital strap portion 1320 and the anterior portions 1311 of the parietal strap portion 1310 are all integrally formed, for example cut from a foam and textile laminated sheet, with rigidisers 1323 inserted into the anterior portions 1324 of the occipital strap portion 1320. In other examples, any one or more of these portions may be formed separately from some or all of the other portions.5.4.2 Rigidised Lateral Portions

[0413] Figs. 7F-7O show a positioning and stabilising structure 1300 according to another example of the present technology. The positioning and stabilising structure 1300 is for a head-mounted display system 1000 comprising a head-mounted display unit 1200 comprising a display unit housing 1205 comprising a display. The head-mounted display unit 1200 and components thereof such as a display unit housing 1205 and arms 1210 are not shown in Figs. 7F-7O but may be as described elsewhere herein. Fig. 7E shows a head-mounted display unit 1200 comprising a display unit housing 1205 having arms 1200. The positioning and stabilising structure 1300 shown in Figs. 7F-7O is intended to be used to support a similar head-mounted display unit 1200 on the user’s head, optionally without a frontal connector 1345. That is, the positioning and stabilising structure 1300 may support the head-mounted display unit 1200 solely via arms 1210 extending posteriorly from a display unithousing 1205 of the head-mounted display unit 1200). For example, the positioning and stabilising structure 1300 may be constructed and arranged to hold the headmounted display unit 1200 in an operable position on the user’s head in use.

[0414] The positioning and stabilising structure 1300 may comprise a pair of lateral portions 1301 each constructed and arranged to be positioned on a respective lateral side of the user’s head in use. In this example, each lateral portion 1301 comprises a respective one of a pair of arm connection portions 1335 each configured to be connected to a respective one of a pair of arms 1210 extending posteriorly from the display unit housing 1205 on respective sides of the user’s head. For example, the arm connection portions 1335 may be constructed and arranged to form snap fit connections with the arms 1210 extending from the display unit housing 1200. That said, any suitable manner of connection is to be understood to be applicable. The arm connection portions 1335 as shown in Figs. 7F-7O comprise an opening which is configured to connect to the arms 1210 of the head-mounted display unit 1200. The opening may receive a clip portion attachable to the arms 1210. Different clip portions may be installed in the openings of the arm connection portions 1335 to allow for connection to different head-mounted display units 1200. The openings forming the arm connection portions 1335 in this example are square, which may help resist rotation of the components received in the opening. As will be described, the lateral portions 1301 may advantageously be configured to fixedly connect with arms 1210 of a head-mounted display unit 1200 so as to prevent rotation of the arms 1210 with respect to the lateral portions 1301. This may advantageously facilitate the positioning and stabilising structure 1300 to support the weight of the head-mounted display unit 1200 solely via the arms 1205 without a strap connection to the top of the headmounted display unit 1200 and, in some forms of the technology, without engagement of the head-mounted display unit 1200 against the user’s face. In other examples, the openings in the arm-connection portions 1335 may be other non-circular shapes (hexagon, squircle, oval, rectangle) or may be circular but may include a feature (e.g. a keyed connection) to prevent rotation of the arms 1210 or the component within the opening that the arms 1210 connect to.

[0415] With reference to Fig. 7F and 70 in particular, the positioning and stabilising structure 1300 may comprise multiple portions configured to engage theuser’s head in different regions. The positioning and stabilising structure 1300 may comprise a frontal strap portion 1394 formed at least partially by the lateral portions 1301, the frontal strap portion 1394 being constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head. The positioning and stabilising structure 1300 may comprise a parietal strap portion 1320 formed at least partially by the lateral portions 1301, the parietal strap portion 1320 being constructed and arranged to engage the user’s head at a region overlying the parietal bones of the user’s head in use. Additionally, the positioning and stabilising structure 1300 may comprise an occipital strap portion 1320 formed at least partially by the lateral portions 1301, the occipital strap portion 1320 constructed and arranged to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use.

[0416] Each lateral portion 1301 may further comprise a rigidised portion 1309 (identified in Fig. 7J, having a shape similar to the shape of the rigidiser 1305, which will be described). The rigidised portion 1309 may be stiffer than one or more adjacent portions. In some examples the rigidised portion 1309 is rigidised by a rigidiser provided to or within the lateral portion 1301. Figs. 7J and 7K, which show a lateral portion 1301 and a rigidiser 1305, respectively. In this example, the rigidiser 1305 is within the lateral portion 1301, as will be described in more detail. The rigidiser 1305 may be a component that at least partially rigidises the lateral portion 1301 and the ridigised portion 1309 of the lateral portion 1301 may be the portion of the lateral portion 1301 that is rigidised and which may be rigidised at least partially by the rigidiser 1305.

[0417] With reference to Figs. 7J and 7K, each rigidised portion 1309 of the lateral portion 1301 in this example comprises a first portion 1305a located within the frontal strap portion 1394, a second portion 1305b located within the parietal strap portion 1310 and a third portion 1305c located within the occipital strap portion 1320. The rigidised portion 1309 may be partially within each of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320. The rigidised portion 1309 may advantageously hold the shape of the positioning and stabilising structure 1300 and may advantageously position each of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 in the correctgeneral location on the user’s head in use during donning of the head-mounted display system 1000.

[0418] In some examples of the present technology, the lateral portions 1301 are able to conform to the shape of the user’s head. Advantageously, this allows the lateral portions 1301 to fit snugly, securely and comfortably to the user’s head in use, despite a portion of each lateral portion 1301 being rigidised. In each rigidised portion 1309, the first portion 1305a, the second portion 1305b and the third portion 1305c of said rigidised portion 1309 are all able to flex with respect to each other. For example, each of the first portion 1305a, the second portion 1305b and the third portion 1305c are able to flex independently of the others. Advantageously, this facilitates the lateral portion 1301 conforming to the user’s head and having the ability to flex to fit to a wide range of head shapes and sizes. The three portions of the rigidised portion 1309 are able to flex medially to engage the user’s head and substantially match the user’s head curvature. In each lateral portion 1301, the respective rigidised portion 1309 may extend from proximate the respective arm connection portion 1335 into each of the frontal strap portion 1394, the parietal strap portion 1310 and the occipital strap portion 1320. This arrangement may advantageously provide for force transfer from the arm connection portion 1335 to all of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320.

[0419] With reference to Figs. 7 J, 7K and 70, each rigisider 1305 may comprise a central portion 1307 substantially central with respect to the shape of the rigidiser 1305. The central portion 1307 may be located superior to and substantially aligned with the user’s ear in use. Each rigidiser 1305 may comprise a portion extending from the central portion 1307 in an anterosuperior direction in use. This portion may extend into the frontal strap portion 1394 in use and may partially form the first portion 1305a of the rigidised portion 1309 of the lateral portion 1301. Additionally or alternatively, each rigidiser 1305 may comprise a portion extending from the central portion 1307 in a posterosuperior direction in use. This portion may extend into the parietal strap portion 1310 in use and may partially form the second portion 1305b of the rigidised portion 1309 of the lateral portion 1301. Additionally or alternatively, each rigidiser 1305 may comprise a portion extending from the central portion 1307 in a posteroinferior direction in use. This portion may extend into the occipital strapportion 1320 in use and may partially form the third portion 1305c of the rigidised portion 1309 of the lateral portion 1301.

[0420] Each arm connection portion 1335 may be constructed and arranged to fixedly connect to the respective one of the pair of arms 1210 extending posteriorly from the display unit housing 1205 substantially without permitting rotation of the respective arm with respect to the arm connection portion 1335. This may advantageously facilitate the arm connection portion 1335 to resist moments applied by the arm 1210 to support the weight of the head-mounted display unit 1200. In particular, the arm connection portions 1335 are constructed and arranged to fixedly connect to respective arms 1210 of the pair of arms 1210 extending posteriorly from the display unit housing 1205 substantially without permitting rotation of the respective arms 1210 with respect to the rigidised portions 1309. In some forms of the present technology, the positioning and stabilising structure 1300 is able to support substantially the entire weight of the head-mounted display unit 1200 via the arm connection portions 1335. This may advantageously facilitate the head-mounted display unit 1200 to be supported in an in-use position without the need to be in contact with the user’s face.

[0421] Some prior art head-mounted display systems may rely on headgear straps pulling a head-mounted display unit against the user’s face (e.g. in a posterior direction) to hold it in position. That is, the headgear and display unit may “clamp” the user’s head to remain in place. This may be uncomfortable for the user, especially for a long period of use. The positioning and stabilising structure 1300 and headmounted display system 1000 of the present technology may advantageously support the weight of the head-mounted display unit 1200 via the arms 1210 and strap portions of the positioning and stabilising structure 1300 such that the head-mounted display unit 1200 does not need to be pulled hard against the user’s face. This may provide for highly stable and yet more comfortable head-mounted display system 1000, at least for longer periods, than some prior art systems.5.4.2.1 Layers of the lateral portions

[0422] In some examples of the present technology, each lateral portion 1301 is at least partially formed in a layered construction. Figs. 7G and 7H illustrate the layered construction in one example. The layered construction in this examplecomprises a user-facing layer 1302 facing the user’s head in use. In this example, a rigidiser 1305 is provided on the opposite side of the user-facing layer 1302 to the user’s head in use. In this example the rigidiser 1305 at least partially forms the rigidised portion 1309 of the lateral portion 1301 to which it is provided. The rigidiser 1305 is constructed and arranged to stiffen the respective lateral portion 1301 within the rigidised portion 1309. In use, much or all of the user-facing layer 1302 will engage and contact the user’s head. The user-facing layer 1302 may comprise a textile material forming a user-facing surface (e.g. an inward / medially facing surface). In some examples, the user-facing layer 1302 comprises a laminate comprising a foam layer and the textile material. This may provide for a comfortable feeling and aesthetically pleasing positioning and stabilising structure 1300. In some examples, the foam layer is formed from PU foam, but may also be formed from any other suitable foam. The textile material may be Nylon or a combination of Nylon and elastane, or may be formed from any other suitable textile material(s) such as polyester or polypropylene, by way of example only.

[0423] The ridigiser 1305 may be formed from a polymer material and may for example be formed by injection moulding. For example, the rigidser 1305 may be formed from Nylon or PCABS. In some examples the rigidisers 1305 are formed from a thermoplastic material. In some examples the rigidisers 1305 may be formed from a thermoplastic elastomer, such as Hytrel, by way of example only. In the illustrated example, the rigidiser 1305 is formed (e.g. moulded) in a non-planar shape and imparts a three-dimensional curved shape to the respective lateral portion 1301. The three-dimensional curved shape imparted to the lateral portions 1301 may approximate the curvature of a head surface that each lateral portion 1301 engages in use. This may reduce the amount of deformation required in each lateral portion 1301 during fitting, which may provide for a comfortable fit. However, the rigidiser 1305 is able to flex away from the non-planar shape in use to conform to the shape of the user’s head. This may provide for a comfortable fit across a wide range of users.

[0424] In the example shown in Figs. 7F-7O, each rigidiser 1305 is constructed and arranged to resist bending towards directions parallel to the sagittal plane of the user’s head (e.g. superior, inferior, anterior and posterior) in use more so than towards directions normal to the sagittal plane of the user’s head (e.g. medial and lateral) inuse. As shown in Fig. 71 for example, the rigidiser 1305 is thin in comparison to its width and height. Each of the portions of the rigidiser 1305 corresponding to each of the first portion 1305a, the second portion 1305b and the third portion 1305c of the rigidised portion 1309 are therefore readily able to bend towards medial and lateral directions due to the thin cross section providing little resistance to bending towards these directions. The other dimension of the cross section of each rigidiser 1305, which may be considered a width or height dimension and which resists bending towards the superior, inferior, anterior or posterior directions in use, is much larger than the thickness and therefore provides much more resistance to bending. The result is a rigidiser 1305 that is readily able to conform to the shape of user’s head in use to lock the positioning and stabilising structure 1300 in place on the user’s head, while also supporting weight of the head-mounted display unit 1200 due to resistance to bending towards directions parallel to the sagittal plane of the user’s head in use.

[0425] As shown in Figs. 7H and 71, the layered construction comprises a nonuser facing layer 1303 on an opposite side of the rigidiser 1305 to the user-facing layer 1302. The non-user facing layer 1303 may face away from the user’s head in use. The non-user facing layer 1303 may comprise a textile material forming a nonuser facing surface (e.g. an outward / laterally facing surface). In some examples, the non-user facing layer 1303 comprises a laminate comprising a foam layer and the textile material. This may provide for a comfortable feeling and aesthetically pleasing positioning and stabilising structure 1300. In some examples, the foam layer is formed from PU foam or any other suitable foam. The textile material may be Nylon, a combination of Nylon and elastane, or any other suitable textile material. The non- user facing layer 1303 may be formed from the same material as the user-facing layer 1302. In some examples the non-user facing layer 1303 may be formed from a different material to the user-facing layer 1302.

[0426] In the illustrated example, regions of the lateral portion 1301 not occupied by the rigidiser 1305 are formed at least partially by the user-facing layer 1302 and the non-user facing layer 1303. In the illustrated example, because the user-facing layer 1302 and non-user facing layer 1303 comprise foam layers, the user is unable to feel, or unlikely to notice, the edges of the rigidiser 1305 in use. In other examples,the user-facing layer 1302 and non-user facing layer 1303 comprise a gel, a spacer fabric, an elastomer or other cushioning material.

[0427] As shown in Figs. 7G-7J, the layered construction comprises at least one stiffening layer 1304 proximate the arm connection portion 1335. In this example the stiffening layer 1304 surrounds the arm connection portion 1335. This may advantageously stiffen the arm connection portion 1335, facilitating resistance against movement of the arms 1210 in use with respect to the positioning and stabilising structure 1300. The arm connection portion 1335 may overlap with the rigidiser 1305 (shown in Fig. 7H). Advantageously, this may facilitate transfer of forces to the rigidised portion 1309, facilitating the positioning and stabilising structure 1300 as a whole to resist rotation or other movement of the arms 1210. In the illustrated example, as shown in Fig. 7H, the layered construction may comprise two stiffening layers 1304. The two stiffening layers 1304 overlap with the rigidiser 1305 with a portion of the rigidiser 1305 being between the two stiffening layers. In this example, each stiffening layer 1304 may comprise a stiffening mesh. In other examples, any suitable stiffening structure may be applied, such as a thick film or moulded rigidiser, as examples only.

[0428] In the example shown in Figs. 7F-7O, each rigidiser 1305 comprises a recessed portion 1306 (see Fig. 7K). The recessed portion 1306 may reduce the width and / or height of the rigidiser 1305 proximate the arm connection portion 1335, for example to provide space for the opening in the illustrated example. In other examples of the present technology, the rigidiser 1305 in each lateral portion 1301 may surround the arm connection portion 1335. In further examples, the rigidiser 1305 may define the arm connection portion 1335 or an opening forming the arm connection portion 1335. In such examples the rigidiser 1305 may comprise an opening at least partially defining the arm connection portion 1335. In some examples the arms 1210 may connect directly to the rigidiser 1305.

[0429] In some examples, the positioning and stabilising structure 1300 may be constructed to guide a cable connected to the head-mounted display unit 1200, such as a power cable or signal cable, along a predetermined path, such as along the occipital strap portion 1320. The occipital strap portion 1320 may comprise a guide configured to receive the cable and direct it in a posteroinferior direction along the occipital strapportion 1320. The guide may be a clip, a loop of material, a sleeve or other component constructed to receive or attach to a cable so as to hold the cable in place.5.4.2.2 Adjustable strap portions

[0430] One or more of the strap portions of the positioning and stabilising structure 1300 may be adjustable in length.

[0431] In some examples, the frontal strap portion 1394 is adjustable in length. Figs. 7L and 7M show the two lateral portions 1301 separately. In the example shown in Figs. 7F, 7L and 7M, the frontal strap portion 1394 comprises a first portion 1394a extending from one of the lateral portions 1301, the first portion 1394a passing through an opening 1394b provided to the other of the lateral portions 1301 and being secured back to itself.

[0432] In some examples, the parietal strap portion 1310 is adjustable in length. In the illustrated example, the parietal strap portion 1310 comprises a first portion 1310a extending from one of the lateral portions 1301, the first portion 1310a passing through an opening 1310b provided to the other of the lateral portions 1301 and being secured back to itself.

[0433] In some examples, the occipital strap portion 1320 is adjustable in length. In the illustrated example, the occipital strap portion 1320 comprises a first portion 1320a extending from one of the lateral portions 1301, the first portion 1320a passing through an opening 1320b provided to the other of the lateral portions 1301 and being secured back to itself.

[0434] The lateral portion 1301 shown in Fig. 7L has eyelets forming openings (e.g. 1394b, 1310b, 1320b) to receive strap portions (1394a, 1310a, 1320a) attached to the lateral portion 1301 shown in Fig. 7M. The eyelets may be formed from stainless steel, a polymer material or any other suitable material. Each of the first portions 1394a, 1310a and / or 1320a may be constructed to form a hook-and-loop connection with itself, respectively. The end of each first portion 1394a, 1310a and / or 1320a may comprise a portion having a hook material configured to attach to a non-user facing layer of itself formed from a loop material (e.g. a textile material).

[0435] In other examples, any one or more of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 may comprise domes, magnets, a sliding buckle, a ladderlock buckle, a dial adjustment mechanism or any other suitable adjustment feature providing for selective adjustment of the effective length of the strap portion. In further examples any one or more of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 may not be selectively adjustable in length and may instead be elastically extendable to automatically adjust in length to fit the user’s head. Further still, in other examples any one or more of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 may not be adjustable in length.

[0436] Advantageously, the ability for all of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 to be adjusted enables the positioning and stabilising structure 1300 to fit snugly and securely to a wide range of user head shapes and sizes. Furthermore, the positioning and stabilising structure 1300 being securely but comfortably locked to the shape of the user’s head may advantageously facilitate the positioning and stabilising structure 1300 to resist rotation of the arms 1210, thereby supporting much, or all, of the weight of the headmounted display unit 1200 in use. This may advantageously reduce the amount of force with which the head-mounted display unit 1200 needs to be pulled against the user’s face, to achieve stability in use.

[0437] Another aspect of some forms of the present technology is that, one or more of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 may comprise rigidised lateral portions separated by a non-rigidised medial portion. The positioning and stabilising structure 1300 shown in Figs. 7F-7O has this aspect. Each of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 is formed at its lateral ends by a respective one of the rigidised portions 1309 of the lateral portions 1301 and is formed between its lateral ends by non-rigidised strap portion (e.g. the first portions 1394a, 1310a and 1320a, which are not rigidised). The lack of rigid connection within the positioning and stabilising structure 1300 of one lateral portion 1301 to the other lateral portion 1301 means that the lateral portions 1301 are able to move medially and laterally with respect to each other to adjust to the width of the user’s head (the arms 1210 attachedto the head-mounted display unit 1200 may also move or flex medially / laterally as required). Then, the three limbs of the rigidised portions 1309 (e.g. the portions of each rigidised portion 1309 that form the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320) are able to flex independently to fit well to the local curvature of the user’s head at or proximate the frontal, parietal and occipital bones. In other examples, one or more of the frontal strap portion 1394, parietal strap portion 1310 and occipital strap portion 1320 may be rigidised along its full length from one lateral portion 1301 to the other lateral portion 1301.5.4.2.3 Counterweights

[0438] Fig. 7N shows a positioning and stabilising structure 1300 according to another example of the present technology. In this example the parietal strap portion 1310 is constructed and arranged to support one or more counterweights 1386.

[0439] As illustrated, the parietal strap portion 1310 is constructed and arranged to support a pair of counterweights 1386, each spaced from and located on opposing sides of the mid-sagittal plane of the user’s head in use. The lateral portions 1301 may be constructed and arranged to support the pair of counterweights 1386 in the parietal strap portion 1310. The counterweights 1386 may be provided to the portion of the lateral portion 1301 that forms part of the parietal strap portion 1310. The one or more counterweights 1386 may be configured to attach to the parietal strap portion 1310 with a hook-and-loop connection. For example, each counterweight 1386 may be provided with hook material configured to form a hook-and-loop connection with the loop material forming the non-user facing layer 1303 of the lateral portion 1301.

[0440] Also as illustrated in Fig. 7N, the occipital strap portion 1320 is constructed and arranged to support a pair of counterweights 1386, each spaced from and located on opposing sides of the mid-sagittal plane of the user’s head in use. The lateral portions 1301 may be constructed and arranged to support the pair of counterweights 1386 in the occipital strap portion 1320. The counterweights 1386 may be provided to the portion of the lateral portion 1301 that forms part of the occipital strap portion 1320. The one or more counterweights 1386 may be configured to attach to the occipital strap portion 1320 with a hook-and-loop connection. For example, each counterweight 1386 may be provided with hook material configured toform a hook-and-loop connection with the loop material forming the non-user facing layer 1303 of the lateral portion 1301.

[0441] The counterweights 1386 may advantageously counter some of the weight of the head-mounted display unit 1200 transferred to the positioning and stabilising structure 1300 via the arms 1210. The counterweights 1386 may advantageously shift the overall centre of mass of the head-mounted display system 1000 posteriorly, closer to the user’s neck or centre of the head (e.g. mid-coronal plane), which may reduce or prevent the weight of the head-mounted display unit 1200 from pulling the user’s head anteriorly and inferiorly. The counterweights 1386 are provided in pairs on each of the parietal strap portion 1310 and occipital strap portion 1320, which may provide for more stability than a single but twice as heavy counterweight 1386 provided at the posterior-most point of each strap portion (e.g. in the mid-sagittal plane). Counterweights 1386 are advantageously provided to both the parietal strap portion 1310 and occipital strap portion 1320 to allow the overall weight of the counterweights to be adjusted but removing the two counterweights 1386 on one of the parietal strap portion 1310 or occipital strap portion 1320, or removing all, depending on preference, neck strength and / or to vary cheek or forehead pressure (moving counterweights from one of the parietal strap portion 1310 and the occipital strap portion 1320 to the other may allow the user to switch between more cheek pressure or more forehead pressure, when the head-mounted display unit 1200 engages the users cheeks and forehead). Additionally, four smaller counterweights 1386 rather than one large counterweight allows the weight to be well spread out on the back of the user’s head. The counterweights 1386 may be formed from any suitable heavy material and may be overmoulded with a soft material, e.g. an elastomer.5.5 CLEANING

[0442] In some forms, the head-mounted display system 1000 or at least a portion thereof, is designed to be used by a single user, and cleaned in a home of the user, e.g., washed in soapy water, without requiring specialised equipment for disinfection and sterilisation. Specifically, the positioning and stabilizing structure 1300 and the interfacing structure 1100 are designed to be cleaned, as they are both in direct contact with the user’s head.

[0443] In some other forms, the components of the positioning and stabilizing structure 1300 and interfacing structure 1100 are used in labs, clinics and hospitals wherein a single head-mounted display may be reused on multiple persons or used during medical procedures. In each of the labs, clinics and hospitals the head-mounted displays, or relevant components thereof, can be reprocessed and be exposed to, for example, processes of thermal disinfection, chemical disinfection and sterilisation. As such, the design of the positioning and stabilizing structure and interfacing structure may need to be validated for disinfection and sterilisation of the mask in accordance with ISO 17664.

[0444] Materials may be chosen to withstand reprocessing. For example, robust materials may be used in the positioning and stabilizing structure 1300 to withstand exposure to high level disinfection solutions and agitation with a brush. Further, some components of the positioning and stabilizing structure are separable, and in-use may be disconnected to improve the reprocessing efficacy.

[0445] In some examples, the interfacing structure 1100 may, in use, be in contact with the user’s head and therefor may become dirty (e.g., from sweat). The interfacing structure 1100 may be designed to be removed from the display unit housing 1205, to provide the ability to remove it for cleaning and / or replacement. It may be desirable to wash the interfacing structure 1100 while not getting the positioning and stabilizing structure 1300 wet. Alternatively or in addition, the positioning and stabilizing structure 1300 may be dirty from contact with the user’s head, and may be removed for cleaning and / or replacement independently of the interfacing structure 1100. In either case, this may be facilitated by allowing these components to disconnect for such a purpose.

[0446] In some examples, a cover (e.g., constructed from a textile, silicone, etc.) may be removably positioned over the interfacing structure and can be removed to be cleaned and / or replaced after each use. The cover may allow the interface structure 3400 to remain fixed to the display unit housing 1205, and still provide a surface that can be easily cleaned after being used.5.6 EXTERNAL COMPUTER

[0447] In some forms, the head-mounted display system 1000 (e.g., VR, AR, and / or MR) may be used in conjunction with a separate device, like a computer or video game console. For example, the display interface may be electrically connected to the separate device.

[0448] In some forms, at least some processing for the head-mounted display system 1000 may be performed by the separate device. The separate device may include a larger and / or more powerful processor than could be comfortably supported by the user (e.g., the processor of the separate device may be too heavy for the user to comfortably support on their head).6 GLOSSARY

[0449] For the purposes of the present technology disclosure, in certain forms of the present technology, one or more of the following definitions may apply. In other forms of the present technology, alternative definitions may apply.6.1 GENERAL

[0450] Ambient. In certain forms of the present technology, the term ambient will be taken to mean (i) external of the display interface and / or user, and (ii) immediately surrounding the display interface and / or user.

[0451] For example, ambient light with respect to a display interface may be the light immediately surrounding the user, e.g., the light in the same and / or adjacent room as a user, and / or natural light from the sun.

[0452] In certain forms, ambient (e.g., acoustic) noise may be considered to be the background noise level in the room where a user is located, other than for example, noise generated by the display device or emanating from speakers connected to the display device. Ambient noise may be generated by sources outside the room.

[0453] Leak'. The word leak will be taken to be an unintended exposure to light. In one example, leak may occur as the result of an incomplete seal between a display unit and a users’ face.

[0454] Noise, radiated (acoustic): Radiated noise in the present document refers to noise which is carried to the user by the ambient air. In one form, radiated noise may be quantified by measuring sound power / pressure levels of the object in question according to ISO 3744.

[0455] User: A person operating the display interface and / or viewing images provided by the display interface. For example, the person may be wearing, donning, and / or doffing the display interface..6.1.1 Materials

[0456] Silicone or Silicone Elastomer: A synthetic rubber. In this specification, a reference to silicone is a reference to liquid silicone rubber (LSR) or a compression moulded silicone rubber (CMSR). One form of commercially available LSR is SILASTIC (included in the range of products sold under this trademark), manufactured by Dow Corning. Another manufacturer of LSR is Wacker. Unless otherwise specified to the contrary, an exemplary form of LSR has a Shore A (or Type A) indentation hardness in the range of about 35 to about 45 as measured using ASTM D2240

[0457] Polycarbonate: a thermoplastic polymer of Bisphenol-A Carbonate.6.1.2 Mechanical properties

[0458] Resilience: Ability of a material to absorb energy when deformed elastically and to release the energy upon unloading.

[0459] Resilient: Will release substantially all of the energy when unloaded. Includes e.g., certain silicones, and thermoplastic elastomers.

[0460] Hardness: The ability of a material per se to resist deformation (e.g., described by a Young’s Modulus, or an indentation hardness scale measured on a standardised sample size).• ‘Soft’ materials may include silicone or thermo-plastic elastomer (TPE), and may, e.g., readily deform under finger pressure.• ‘Hard’ materials may include polycarbonate, polypropylene, steel or aluminium, and may not e.g., readily deform under finger pressure.

[0461] Stiffness (or rigidity) of a structure or component'. The ability of the structure or component to resist deformation in response to an applied load. The load may be a force or a moment, e.g., compression, tension, bending or torsion. The structure or component may offer different resistances in different directions. The inverse of stiffness inflexibility.

[0462] Floppy structure or component: A structure or component that will change shape, e.g., bend, when caused to support its own weight, within a relatively short period of time such as 1 second.

[0463] Rigid structure or component'. A structure or component that will not substantially change shape when subject to the loads typically encountered in use. An example of such a use may be setting up and maintaining a user interface in sealing relationship.

[0464] As an example, an I-beam may comprise a different bending stiffness (resistance to a bending load) in a first direction in comparison to a second, orthogonal direction. In another example, a structure or component may be floppy in a first direction and rigid in a second direction.6.2 MATERIALS

[0465] Closed-cell foam'. Foam comprising cells that are completely encapsulated, i.e., closed cells.

[0466] Elastane'. A polymer made from polyurethane.

[0467] Elastomer. A polymer that displays elastic properties. For example, silicone elastomer.

[0468] Ethylene-vinyl acetate (EVA)'. A copolymer of ethylene and vinyl acetate.

[0469] Fiber. A filament (mono or poly), a strand, a yam, a thread or twine that is significantly longer than it is wide. A fiber may include animal-based material such as wool or silk, plant-based material such as linen and cotton, and synthetic material such as polyester and rayon. A fiber may specifically refer to a material that can be interwoven and / or interlaced (e.g., in a network) with other fibers of the same or different material.

[0470] Foam-. Any material, for example polyurethane, having gas bubbles introduced during manufacture to produce a lightweight cellular form.

[0471] Neoprene-. A synthetic rubber that is produced by polymerization of chloroprene. Neoprene is used in trade products: Breath-O-Prene.

[0472] Nylon-. A synthetic polyamide that has elastic properties and can be used, for example, to form fibres / filaments for use in textiles.

[0473] Open-cell foam: Foam comprising cells, i.e., gas bubbles that aren’t completely encapsulated, i.e., open cells.

[0474] Polycarbonate: a typically transparent thermoplastic polymer of Bisphenol-A Carbonate.

[0475] Polyethylene: A thermoplastic that is resistant to chemicals and moisture.

[0476] Polyurethane (PU): A plastic material made by copolymerizing an isocyanate and a polyhydric alcohol and, for example, can take the form of foam (polyurethane foam) and rubber (polyurethane rubber).

[0477] Semi-open foam: Foam comprising a combination of closed and open(encapsulated) cells.

[0478] Silicone or Silicone Elastomer: A synthetic rubber. In this specification, a reference to silicone is a reference to liquid silicone rubber (LSR) or a compression moulded silicone rubber (CMSR). One form of commercially available LSR is SILASTIC (included in the range of products sold under this trademark), manufactured by Dow Corning. Another manufacturer of LSR is Wacker. Unless otherwise specified to the contrary, an exemplary form of LSR has a Shore A (or Type A) indentation hardness in the range of about 35 to about 45 as measured using ASTM D2240.

[0479] Spacer Fabric: A composite construction comprised of two outer textile substrates joined together and kept apart by an intermediate layer of monofilaments.

[0480] Spandex: An elastic fibre or fabric, primarily comprised of polyurethane. Spandex is used in trade products: Lycra.

[0481] Textile-. A material including at least one natural or artificial fiber. In this specification, a textile may refer to any material that is formed as a network of interwoven and / or interlaced fibers. A type of textile may include a fabric, which is constructed by interlacing the fibers using specific techniques. These include weaving, knitting, crocheting, knotting, tatting, tufting, or braiding. Cloth may be used synonymously with fabric, although may specifically refer to a processed piece of fabric. Other types of textiles may be constructed using bonding (chemical, mechanical, heat, etc.), felting, or other nonwoven processes. Textiles created through one of these processes are fabric-like, and may be considered synonymous with fabric for the purposes of this application.

[0482] Thermoplastic Elastomer (TPE)-. Are generally low modulus, flexible materials that can be stretched at room temperature with an ability to return to their approximate original length when stress is released. Trade products that use TPE include: Hytrel, Dynaflex, Medalist

[0483] Thermoplastic Polyurethane (TPU)-. A thermoplastic elastomer with a high durability and flexibility.6.3 MECHANICAL PROPERTIES

[0484] Resilience: Ability of a material to absorb energy when deformed elastically and to release the energy upon unloading.

[0485] Resilient: Will release substantially all of the energy when unloaded. Includes e.g., certain silicones, and thermoplastic elastomers.

[0486] Hardness: The ability of a material per se to resist deformation (e.g., described by a Young’s Modulus, or an indentation hardness scale measured on a standardised sample size).• ‘Soft’ materials may include silicone or thermo-plastic elastomer (TPE), and may, e.g., readily deform under finger pressure.• ‘Hard’ materials may include polycarbonate, polypropylene, steel or aluminium, and may not e.g., readily deform under finger pressure.

[0487] Stiffness (or rigidity) of a structure or component: The ability of the structure or component to resist deformation in response to an applied load. The load may be a force or a moment, e.g., compression, tension, bending or torsion. The structure or component may offer different resistances in different directions.

[0488] Floppy structure or component: A structure or component that will change shape, e.g., bend, when caused to support its own weight, within a relatively short period of time such as 1 second.

[0489] Rigid structure or component: A structure or component that will not substantially change shape when subject to the loads typically encountered in use.6.4 ANATOMY

[0490] The following definitions correspond references identified in Figs. 1-2.6.4.1 Anatomy of the face

[0491] Ala: the external outer wall or "wing" of each nostril (plural: alar)

[0492] Alare: The most lateral point on the nasal ala.

[0493] Alar curvature (or alar crest) point'. The most posterior point in the curved base line of each ala, found in the crease formed by the union of the ala with the cheek.

[0494] Auricle: The whole external visible part of the ear.

[0495] (nose) Bony framework: The bony framework of the nose comprises the nasal bones, the frontal process of the maxillae and the nasal part of the frontal bone.

[0496] Bridge (nasal): The nasal bridge is the midline prominence of the nose, extending from the Sellion to the Pronasale.

[0497] (nose) Cartilaginous framework: The cartilaginous framework of the nose comprises the septal, lateral, major and minor cartilages.

[0498] Cheilion: A point located at the corner of the mouth.

[0499] Columella: the strip of skin that separates the nares and which runs from the pronasale to the upper lip.

[0500] Columella angle: The angle between the line drawn through the midpoint of the nostril aperture and a line drawn perpendicular to the Frankfort horizontal while intersecting subnasale.

[0501] Endocanthion: The point at which the upper and lower eyelids meet, proximal to the Sellion.

[0502] Epicranius: The Epicranius, or frontal belly, refers to structures that cover the cranium.

[0503] External occipital protuberance-. A protuberance on the outer surface of the occipital bone.

[0504] Frankfort horizontal plane-. A line extending from the most inferior point of the orbital margin to the left tragion. The tragion is the deepest point in the notch superior to the tragus of the auricle.

[0505] Glabella: Located on the soft tissue, the most prominent point in the midsagittal plane of the forehead.

[0506] Interpupillary Distance-. The distance between the centres of the pupils of the eyes.

[0507] Lateral nasal cartilage: A generally triangular plate of cartilage. Its superior margin is attached to the nasal bone and frontal process of the maxilla, and its inferior margin is connected to the greater alar cartilage.

[0508] Lip, inferior (labrale inferius): A point on the face between the mouth and supramenton, lying in the median sagittal plane.

[0509] Lip, superior (labrale superius): A point on the face between the mouth and nose, lying in the median sagittal plane.

[0510] Greater alar cartilage: A plate of cartilage lying below the lateral nasal cartilage. It is curved around the anterior part of the naris. Its posterior end isconnected to the frontal process of the maxilla by a tough fibrous membrane containing three or four minor cartilages of the ala.

[0511] Nares (Nostrils)'. Approximately ellipsoidal apertures forming the entrance to the nasal cavity. The singular form of nares is naris (nostril). The nares are separated by the nasal septum.

[0512] Naso-labial sulcus or Naso -labial fold'. The skin fold or groove that runs from each side of the nose to the comers of the mouth, separating the cheeks from the upper lip.

[0513] Naso-labial angle: The angle between the columella and the upper lip, while intersecting subnasale.

[0514] Otobasion inferior: The lowest point of attachment of the auricle to the skin of the face.

[0515] Otobasion superior: The highest point of attachment of the auricle to the skin of the face.

[0516] Pronasale: the most protruded point or tip of the nose, which can be identified in lateral view of the rest of the portion of the head.

[0517] Philtrum: the midline groove that runs from lower border of the nasal septum to the top of the lip in the upper lip region.

[0518] Pogonion: Located on the soft tissue, the most anterior midpoint of the chin.

[0519] Ridge (nasal): The nasal ridge is the midline prominence of the nose, extending from the Sellion to the Pronasale.

[0520] Sagittal plane: A vertical plane that passes from anterior (front) to posterior (rear). The midsagittal plane is a sagittal plane that divides the body into right and left halves.

[0521] Sellion: Located on the soft tissue, the most concave point overlying the area of the frontonasal suture.

[0522] Septal cartilage (nasal): The nasal septal cartilage forms part of the septum and divides the front part of the nasal cavity.

[0523] Subalare: The point at the lower margin of the alar base, where the alar base joins with the skin of the superior (upper) lip.

[0524] Subnasal point: Located on the soft tissue, the point at which the columella merges with the upper lip in the midsagittal plane.

[0525] Supramenton: The point of greatest concavity in the midline of the lower lip between labrale inferius and soft tissue pogonion.

[0526] Superciliary arch: A protuberance of the frontal bone above the eye.

[0527] Temporalis muscle: A muscle in the temporal fossa that serves to raise the lower jaw.

[0528] Temporomandibular joint: A freely moveable joint between the temporal bone and mandible that allows for the opening, closing, protrusion, retraction, and lateral movement of the mandible.

[0529] Vermillion, upper: A red part of the lips covered with stratified squamous epithelium which is in continuity with the oral mucosa of the gingivolabial groove.6.4.2 Anatomy of the skull

[0530] Frontal bone: The frontal bone includes a large vertical portion, the squama frontalis, corresponding to the region known as the forehead.

[0531] Lateral cartilage: Portion of cartilage lateral of the Septal cartilage and inferior to the Nasal bones.

[0532] Mandible: The mandible forms the lower jaw. The mental protuberance is the bony protuberance of the jaw that forms the chin.

[0533] Masseter minor: A lower portion of the Masseter muscle of which raises the lower jaw.

[0534] Maxilla'. The maxilla forms the upper jaw and is located above the mandible and below the orbits. The frontal process of the maxilla projects upwards by the side of the nose, and forms part of its lateral boundary.

[0535] Nasal bones: The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, the "bridge" of the nose.

[0536] Nasion: The intersection of the frontal bone and the two nasal bones, a depressed area directly between the eyes and superior to the bridge of the nose.

[0537] Occipital bone: The occipital bone is situated at the back and lower part of the cranium. It includes an oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal. The curved plate behind the foramen magnum is the squama occipitalis.

[0538] Orbit: The bony cavity in the skull to contain the eyeball.

[0539] Parietal bones: The parietal bones are the bones that, when joined together, form the roof and sides of the cranium.

[0540] Septal cartilage: Cartilage of the nasal septum.

[0541] Sphenoid bone: A wedge shaped bone of the base of the cranium.

[0542] Supraorbital foramen: An opening in the inferior bone of the orbit for the passage of the Supraorbital nerve, artery and vein.

[0543] Temporal bones: The temporal bones are situated on the bases and sides of the skull, and support that part of the face known as the temple.

[0544] Trapezius minor: A triangular- shaped superficial muscle of the upper back.

[0545] Zygomatic bones: The face includes two zygomatic bones, located in the upper and lateral parts of the face and forming the prominence of the cheek.6.5 USER INTERFACE

[0546] Frame-. Frame will be taken to mean a display housing unit that bears the load of tension between two or more points of connection with a headgear and / or a hoop. The frame may seal against the user’s face in order to limit and / or prevent the ingress and / or egress of light.

[0548] Hoop-. Hoop will be taken to mean a form of positioning and stabilizing structure designed for use on a head. For example the hoop may comprise a collection of one or more struts, ties and stiffeners configured to locate and retain a user interface in position on a users’ face for holding a display unit in an operational position in front of a user’s face. Some ties are formed of a soft, flexible, elastic material such as a laminated composite of foam and fabric / textile. In some forms, the term headgear may be synonymous with the term hoop.

[0549] Membrane-. Membrane will be taken to mean a typically thin element that has, preferably, substantially no resistance to bending, but has resistance to being stretched.

[0550] Seal'. May be a noun form ("a seal") which refers to a structure, or a verb form (“to seal”) which refers to the effect. Two elements may be constructed and / or arranged to ‘seal’ or to effect ‘sealing’ therebetween without requiring a separate ‘seal’ element per se.

[0551] Shell-. A shell will be taken to mean a curved, relatively thin structure having bending, tensile and compressive stiffness. For example, a curved structural wall of a mask may be a shell. In some forms, a shell may be faceted. In some forms a shell may be airtight. In some forms a shell may not be airtight.

[0552] Stiffener. A stiffener will be taken to mean a structural component designed to increase the bending resistance of another component in at least one direction.

[0553] Strut: A strut will be taken to be a structural component designed to increase the compression resistance of another component in at least one direction.

[0554] Swivel (noun): A subassembly of components configured to rotate about a common axis, preferably independently, preferably under low torque. In one form, the swivel may be constructed to rotate through an angle of at least 360 degrees. In another form, the swivel may be constructed to rotate through an angle less than 360 degrees.

[0555] Tie (noun): A structure designed to resist tension.6.6 SHAPE OF STRUCTURES

[0556] Products in accordance with the present technology may comprise one or more three-dimensional mechanical structures, for example a mask cushion or an impeller. The three-dimensional structures may be bounded by two-dimensional surfaces. These surfaces may be distinguished using a label to describe an associated surface orientation, location, function, or some other characteristic. For example a structure may comprise one or more of an anterior surface, a posterior surface, an interior surface and an exterior surface. In another example, a seal-forming structure may comprise a face-contacting (e.g., outer) surface, and a separate non-facecontacting (e.g., underside or inner) surface. In another example, a structure may comprise a first surface and a second surface.

[0557] To facilitate describing the shape of the three-dimensional structures and the surfaces, we first consider a cross-section through a surface of the structure at a point, p. See Fig. 3A to Fig. 3E, which illustrate examples of cross-sections at point p on a surface, and the resulting plane curves. Figs. 3A to 3E also illustrate an outward normal vector at p. The outward normal vector at p points away from the surface. In some examples we describe the surface from the point of view of an imaginary small person standing upright on the surface.6.6.1 Curvature in one dimension

[0558] The curvature of a plane curve at p may be described as having a sign (e.g., positive, negative) and a magnitude (e.g., 1 / radius of a circle that just touches the curve at p).

[0559] Positive curvature: If the curve at p turns towards the outward normal, the curvature at that point will be taken to be positive (if the imaginary small personleaves the point p they must walk uphill). See Fig. 3A (relatively large positive curvature compared to Fig. 3B) and Fig. 3B (relatively small positive curvature compared to Fig. 3A). Such curves are often referred to as concave.

[0560] Zero curvature: If the curve at p is a straight line, the curvature will be taken to be zero (if the imaginary small person leaves the point p, they can walk on a level, neither up nor down). See Fig. 3C.

[0561] Negative curvature: If the curve at p turns away from the outward normal, the curvature in that direction at that point will be taken to be negative (if the imaginary small person leaves the point p they must walk downhill). See Fig. 3D (relatively small negative curvature compared to Fig. 3E) and Fig. 3E (relatively large negative curvature compared to Fig. 3F). Such curves are often referred to as convex.6.6.2 Curvature of two dimensional surfaces

[0562] A description of the shape at a given point on a two-dimensional surface in accordance with the present technology may include multiple normal crosssections. The multiple cross-sections may cut the surface in a plane that includes the outward normal (a “normal plane”), and each cross-section may be taken in a different direction. Each cross-section results in a plane curve with a corresponding curvature. The different curvatures at that point may have the same sign, or a different sign.Each of the curvatures at that point has a magnitude, e.g., relatively small. The plane curves in Figs. 3A to 3E could be examples of such multiple cross-sections at a particular point.

[0563] Principal curvatures and directions: The directions of the normal planes where the curvature of the curve takes its maximum and minimum values are called the principal directions. In the examples of Fig. 3 A to Fig. 3E, the maximum curvature occurs in Fig. 3A, and the minimum occurs in Fig. 3E, hence Fig. 3A and Fig. 3E are cross sections in the principal directions. The principal curvatures at p are the curvatures in the principal directions.

[0564] Region of a surface: A connected set of points on a surface. The set of points in a region may have similar characteristics, e.g., curvatures or signs.

[0565] Saddle region: A region where at each point, the principal curvatures have opposite signs, that is, one is positive, and the other is negative (depending on the direction to which the imaginary person turns, they may walk uphill or downhill).

[0566] Dome region: A region where at each point the principal curvatures have the same sign, e.g., both positive (a “concave dome”) or both negative (a “convex dome”).

[0567] Cylindrical region: A region where one principal curvature is zero (or, for example, zero within manufacturing tolerances) and the other principal curvature is non-zero.

[0568] Planar region: A region of a surface where both of the principal curvatures are zero (or, for example, zero within manufacturing tolerances).

[0569] Edge of a surface: A boundary or limit of a surface or region.

[0570] Path: In certain forms of the present technology, ‘path’ will be taken to mean a path in the mathematical - topological sense, e.g., a continuous space curve from / (0) to / (I) on a surface. In certain forms of the present technology, a ‘path’ may be described as a route or course, including e.g., a set of points on a surface. (The path for the imaginary person is where they walk on the surface, and is analogous to a garden path).

[0571] Path length: In certain forms of the present technology, ‘path length’ will be taken to mean the distance along the surface from / (0) to / (I), that is, the distance along the path on the surface. There may be more than one path between two points on a surface and such paths may have different path lengths. (The path length for the imaginary person would be the distance they have to walk on the surface along the path).

[0572] Straight-line distance: The straight-line distance is the distance between two points on a surface, but without regard to the surface. On planar regions, there would be a path on the surface having the same path length as the straight-line distance between two points on the surface. On non-planar surfaces, there may be no paths having the same path length as the straight-line distance between two points.(For the imaginary person, the straight-line distance would correspond to the distance ‘as the crow flies’.)6.6.3 Space curves

[0573] Space curves: Unlike a plane curve, a space curve does not necessarily lie in any particular plane. A space curve may be closed, that is, having no endpoints. A space curve may be considered to be a one-dimensional piece of three-dimensional space. An imaginary person walking on a strand of the DNA helix walks along a space curve. A typical human left ear comprises a helix, which is a left-hand helix, see Fig. 3M. A typical human right ear comprises a helix, which is a right-hand helix, see Fig. 3N. Fig. 30 shows a right-hand helix. The edge of a structure, e.g., the edge of a membrane or impeller, may follow a space curve. In general, a space curve may be described by a curvature and a torsion at each point on the space curve. Torsion is a measure of how the curve turns out of a plane. Torsion has a sign and a magnitude. The torsion at a point on a space curve may be characterised with reference to the tangent, normal and binormal vectors at that point.

[0574] Tangent unit vector (or unit tangent vector): For each point on a curve, a vector at the point specifies a direction from that point, as well as a magnitude. A tangent unit vector is a unit vector pointing in the same direction as the curve at that point. If an imaginary person were flying along the curve and fell off her vehicle at a particular point, the direction of the tangent vector is the direction she would be travelling.

[0575] Unit normal vector: As the imaginary person moves along the curve, this tangent vector itself changes. The unit vector pointing in the same direction that the tangent vector is changing is called the unit principal normal vector. It is perpendicular to the tangent vector.

[0576] Binormal unit vector: The binormal unit vector is perpendicular to both the tangent vector and the principal normal vector. Its direction may be determined by a right-hand rule (see e.g., Fig. 3L), or alternatively by a left-hand rule (Fig. 3K).

[0577] Osculating plane: The plane containing the unit tangent vector and the unit principal normal vector. See Figures 3K and 3L. no

[0578] Torsion of a space curve: The torsion at a point of a space curve is the magnitude of the rate of change of the binormal unit vector at that point. It measures how much the curve deviates from the osculating plane. A space curve which lies in a plane has zero torsion. A space curve which deviates a relatively small amount from the osculating plane will have a relatively small magnitude of torsion (e.g., a gently sloping helical path). A space curve which deviates a relatively large amount from the osculating plane will have a relatively large magnitude of torsion (e.g., a steeply sloping helical path). With reference to Fig. 30, since T2>T1, the magnitude of the torsion near the top coils of the helix of Fig. 30 is greater than the magnitude of the torsion of the bottom coils of the helix of Fig. 30

[0579] With reference to the right-hand rule of Fig. 3M, a space curve turning towards the direction of the right-hand binormal may be considered as having a righthand positive torsion (e.g., a right-hand helix as shown in Fig. 30). A space curve turning away from the direction of the right-hand binormal may be considered as having a right-hand negative torsion (e.g., a left-hand helix).

[0580] Equivalently, and with reference to a left-hand rule (see Fig. 3K), a space curve turning towards the direction of the left-hand binormal may be considered as having a left-hand positive torsion (e.g., a left-hand helix). Hence left-hand positive is equivalent to right-hand negative.6.6.4 Holes

[0581] A surface may have a one-dimensional hole, e.g., a hole bounded by a plane curve or by a space curve. Thin structures (e.g., a membrane) with a hole, may be described as having a one-dimensional hole. See for example the one dimensional hole in the surface of structure shown in Fig. 3F, bounded by a plane curve.

[0582] A structure may have a two-dimensional hole, e.g., a hole bounded by a surface. For example, an inflatable tyre has a two dimensional hole bounded by the interior surface of the tyre. In another example, a bladder with a cavity for air or gel could have a two-dimensional hole. In a yet another example, a conduit may comprise a one-dimension hole (e.g., at its entrance or at its exit), and a two-dimension hole bounded by the inside surface of the conduit. See also the two dimensional hole through the structure shown in Fig. 3H, bounded by a surface as shown.Ill6.7 OTHER REMARKS

[0583] Unless the context clearly dictates otherwise and where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limit of that range, and any other stated or intervening value in that stated range is encompassed within the technology. The upper and lower limits of these intervening ranges, which may be independently included in the intervening ranges, are also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the technology.

[0584] Furthermore, where a value or values are stated herein as being implemented as part of the technology, it is understood that such values may be approximated, unless otherwise stated, and such values may be utilized to any suitable significant digit to the extent that a practical technical implementation may permit or require it.

[0585] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present technology, a limited number of the exemplary methods and materials are described herein.

[0586] When a particular material is identified as being used to construct a component, obvious alternative materials with similar properties may be used as a substitute. Furthermore, unless specified to the contrary, any and all components herein described are understood to be capable of being manufactured and, as such, may be manufactured together or separately.

[0587] It must be noted that as used herein and in the appended claims, the singular forms "a", "an", and "the" include their plural equivalents, unless the context clearly dictates otherwise.

[0588] All publications mentioned herein are incorporated herein by reference in their entirety to disclose and describe the methods and / or materials which are thesubject of those publications. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present technology is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.

[0589] The terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.

[0590] The subject headings used in the detailed description are included only for the ease of reference of the reader and should not be used to limit the subject matter found throughout the disclosure or the claims. The subject headings should not be used in construing the scope of the claims or the claim limitations.

[0591] Although the technology herein has been described with reference to particular examples, it is to be understood that these examples are merely illustrative of the principles and applications of the technology. In some instances, the terminology and symbols may imply specific details that are not required to practice the technology. For example, although the terms "first" and "second" may be used, unless otherwise specified, they are not intended to indicate any order but may be utilised to distinguish between distinct elements. Furthermore, although process steps in the methodologies may be described or illustrated in an order, such an ordering is not required. Those skilled in the art will recognize that such ordering may be modified and / or aspects thereof may be conducted concurrently or even synchronously.

[0592] It is therefore to be understood that numerous modifications may be made to the illustrative examples and that other arrangements may be devised without departing from the spirit and scope of the technology.

Claims

7 CLAIMS1. A positioning and stabilising structure for a head-mounted display system, the head-mounted display system comprising a head-mounted display unit comprising a display unit housing comprising a display, the positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a pair of lateral portions each constructed and arranged to be positioned on a respective lateral side of the user’s head in use, wherein: each lateral portion comprises a respective one of a pair of arm connection portions each configured to be connected to a respective one of a pair of arms extending posteriorly from the display unit housing on respective sides of the user’s head; and each lateral portion comprises a rigidised portion being stiffer than one or more adjacent portions; a frontal strap portion formed at least partially by the lateral portions, the frontal strap portion being constructed and arranged to engage the user’ s head in use in a region overlying the frontal bone of the user’s head; a parietal strap portion formed at least partially by the lateral portions, the parietal strap portion constructed and arranged to engage the user’s head at a region overlying the parietal bones of the user’s head in use; and an occipital strap portion formed at least partially by the lateral portions, the occipital strap portion constructed and arranged to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use; wherein each rigidised portion comprises a first portion located within the frontal strap portion, a second portion located within the parietal strap portion and a third portion located within the occipital strap portion.

2. The positioning and stabilising structure of claim 1, wherein the lateral portions are able to conform to the shape of the user’s head.

3. The positioning and stabilising structure of claim 1 or claim 2, wherein in each rigidised portion, the first portion, the second portion and the third portion of said rigidised portion are all able to flex with respect to each other.

4. The positioning and stabilising structure of any one of claims 1-3, wherein in each lateral portion, the respective rigidised portion extends from proximate the respective arm connection portion into each of the frontal strap portion, the parietal strap portion and the occipital strap portion.

5. The positioning and stabilising structure of any one of claims 1-4, wherein each arm connection portion is constructed and arranged to fixedly connect to the respective one of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arm with respect to the arm connection portion.

6. The positioning and stabilising structure of any one of claims 1-4, wherein the arm connection portions are constructed and arranged to fixedly connect to respective arms of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arms with respect to the rigidised portions.

7. The positioning and stabilising structure of any one of claims 1-6, wherein in use, the positioning and stabilising structure is able to support substantially the entire weight of the head-mounted display unit via the arm connection portions,8. The positioning and stabilising structure of any one of claims 1-7, wherein the arm connection portions are constructed and arranged to form snap fit connections with the arms extending from the display unit housing.

9. The positioning and stabilising structure of any one of claims 1-8, wherein each lateral portion is at least partially formed in a layered construction.

10. The positioning and stabilising structure of claim 9, wherein the layered construction comprises a user-facing layer facing the user’s head in use and a rigidiser on the opposite side of the user-facing layer to the user’s head in use, the rigidiser forming the rigidised portion of the respective lateral portion and constructed and arranged to stiffen the respective lateral portion in the rigidised portion.

11. The positioning and stabilising structure of claim 10, wherein the rigidiser is formed in a non-planar shape and imparts a three-dimensional curved shape to the respective lateral portion.

12. The positioning and stabilising structure of claim 11, wherein the three- dimensional curved shape imparted to the lateral portions approximates curvature of a head surface that each lateral portion engages in use.

13. The positioning and stabilising structure of claim 11 or claim 12, wherein the rigidiser is able to flex away from the non-planar shape in use to conform to the shape of the user’s head.

14. The positioning and stabilising structure of any one of claims 10-13, wherein the layered construction comprises a non-user facing layer on an opposite side of the rigidiser to the user-facing layer.

15. The positioning and stabilising structure of claim 14, wherein regions of the lateral portion not occupied by the rigidiser are formed at least partially by the user-facing layer and the non-user facing layer.

16. The positioning and stabilising structure of any one of claims 10-15, wherein the layered construction comprises at least one stiffening layer proximate the arm connection portion.

17. The positioning and stabilising structure of claim 16, wherein the stiffening layer surrounds the arm connection portion.

18. The positioning and stabilising structure of claim 16 or claim 17, wherein the stiffening layer overlaps with the rigidiser.

19. The positioning and stabilising structure of any one of claims 16-18, wherein the layered construction comprises two stiffening layers, the two stiffening layers overlapping with the rigidiser, a portion of the rigidiser being between the two stiffening layers.

20. The positioning and stabilising structure of any one of claims 16-19, wherein each of the at least one stiffening layer comprises a stiffening mesh.

21. The positioning and stabilising structure of any one of claims 1-20, wherein the frontal strap portion is adjustable in length.

22. The positioning and stabilising structure of claim 21, wherein the frontal strap portion comprises a first portion extending from one of the lateral portions, the first portion passing through an opening provided to the other of the lateral portions and being secured back to itself.

23. The positioning and stabilising structure of any one of claims 1-22, wherein the parietal strap portion is adjustable in length.

24. The positioning and stabilising structure of claim 23, wherein the parietal strap portion comprises a first portion extending from one of the lateral portions, the first portion passing through an opening provided to the other of the lateral portions and being secured back to itself.

25. The positioning and stabilising structure of any one of claims 1-24, wherein the occipital strap portion is adjustable in length.

26. The positioning and stabilising structure of claim 25, wherein the occipital strap portion comprises a first portion extending from one of the lateral portions, the first portion passing through an opening provided to the other of the lateral portions and being secured back to itself.

27. The positioning and stabilising structure of any one of claims 1-26, wherein the parietal strap portion is constructed and arranged to support one or more counterweights.

28. The positioning and stabilising structure of claim 27, wherein the parietal strap portion is constructed and arranged to support a pair of counterweights, each spaced from and located on opposing sides of the mid-sagittal plane of the user’s head in use.

29. The positioning and stabilising structure of claim 27 or claim 28, wherein the lateral portions are constructed and arranged to support the pair of counterweights in the parietal strap portion.

30. The positioning and stabilising structure of any one of claims 27-29, wherein the one or more counterweights are configured to attach to the parietal strap portion with a hook-and-loop connection.

31. The positioning and stabilising structure of any one of claims 1-30, wherein the occipital strap portion is constructed and arranged to support one or more counterweights.

32. The positioning and stabilising structure of claim 31, wherein the occipital strap portion is constructed and arranged to support a pair of counterweights, each spaced from and located on opposing sides of the mid-sagittal plane of the user’s head in use.

33. The positioning and stabilising structure of claim 31 or claim 32, wherein the lateral portions are constructed and arranged to support the pair of counterweights in the occipital strap portion.

34. The positioning and stabilising structure of claim 33, wherein the one or more counterweights are configured to attach to the occipital strap portion with a hook-and-loop connection.

35. A positioning and stabilising structure for a head-mounted display system, the head-mounted display system comprising a head-mounted display unit comprising a display unit housing comprising a display, the positioning and stabilising structure constructed and arranged to hold the head-mounted display unit in an operable position on the user’s head in use, the positioning and stabilising structure comprising: a pair of lateral portions each constructed and arranged to be positioned on a respective lateral side of the user’s head in use, wherein: each lateral portion comprises a respective one of a pair of arm connection portions each configured to be connected to a respective one of a pair of arms extending posteriorly from the display unit housing on respective sides of the user’s head; and each lateral portion comprises a rigidised portion being stiffer than one or more adjacent portions; a frontal strap portion formed at least partially by the lateral portions, the frontal strap portion being constructed and arranged to engage the user’s head in use in a region overlying the frontal bone of the user’s head; a parietal strap portion formed at least partially by the lateral portions, the parietal strap portion constructed and arranged to engage the user’s head at a region overlying the parietal bones of the user’s head in use; and an occipital strap portion formed at least partially by the lateral portions, the occipital strap portion constructed and arranged to engage the user’s head at a region overlying or lying inferior to the occipital bone of the user’s head in use; wherein each arm connection portion is constructed and arranged to fixedly connect to the respective one of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arm with respect to the arm connection portion.

36. The positioning and stabilising structure of claim 35, wherein the arm connection portions are constructed and arranged to fixedly connect torespective arms of the pair of arms extending posteriorly from the display unit housing substantially without permitting rotation of the respective arms with respect to the rigidised portions.

37. The positioning and stabilising structure of claim 35 or claim 36, wherein in use, the positioning and stabilising structure is able to support substantially the entire weight of the head-mounted display unit via the arm connection portions.

38. The positioning and stabilising structure of any one of claims 35-37, wherein the arm connection portions are constructed and arranged to form snap fit connections with the arms extending from the display unit housing.

39. The positioning and stabilising structure of any one of claims 35-38, wherein each rigidised portion comprises a first portion located within the frontal strap portion, a second portion located within the parietal strap portion and a third portion located within the occipital strap portion.

40. The positioning and stabilising structure of any one of claims 35-39, wherein the lateral portions are able to conform to the shape of the user’s head.

41. The positioning and stabilising structure of any one of claims 35-40, wherein in each rigidised portion, the first portion, the second portion and the third portion of said rigidised portion are all able to flex with respect to each other.

42. The positioning and stabilising structure of any one of claims 35-41, wherein in each lateral portion, the respective rigidised portion extends from proximate the respective arm connection portion into each of the frontal strap portion, the parietal strap portion and the occipital strap portion.

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