Patent Publication Number: US-2023157400-A1

Title: Positioning and stabilising structure and system incorporating same

Description:
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. 
     CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Australian Provisional Application No. 2020900953, filed Mar. 27, 2020, U.S. application Ser. No. 16/865,480, filed May 4, 2020, and U.S. application Ser. No. 16/865,526, filed May 4, 2020, each of which is incorporated herein by reference in its entirety. 
     FIELD OF THE TECHNOLOGY 
     The present technology relates to a positioning and stabilising structure to hold a head-mounted display unit and an associated head-mounted display assembly including a display unit and positioning and stabilising structure. The present technology finds particular application in the use of virtual reality head-mounted displays and is herein described in that context. However, it is to be appreciated that the present technology may have broader application and may be used in other head-mounted display arrangements including augmented reality displays. 
     BACKGROUND OF THE TECHNOLOGY 
     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. 
     Virtual reality head-mounted displays enable a user to have a fully immersive experience of a virtual environment and have broad application in fields such as communications, training, medical and surgical practice, engineering and video gaming. 
     Virtual reality head-mounted displays typically are provided as a system or assembly that includes a display unit which is arranged to be held in an operational position in front of a user&#39;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&#39;s face. The user interface structure may extend about the display and define a viewing opening to the display. The user interface structure may engage with the user&#39;s face and include a cushion for user comfort and/or be light sealing to cut ambient light from the display. 
     To hold the display unit in its correct operational position, the head-mounted display system further comprises a positioning and stabilising structure that is disposed on the user&#39;s head. In the past, these positioning and stabilising structures have been formed from straps or expandible rigid structures that are typically applied to the user&#39;s 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&#39;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 positioning and stabilising structure are often heavy and difficult to clean, which further limit the comfort and usability of the system. 
     Thus, there is a need for an improved system that does not suffer from the above-mentioned drawbacks. 
     BRIEF SUMMARY OF THE TECHNOLOGY 
     An aspect of the present technology relates to a positioning and stabilising structure for a head-mounted display unit including a rear support structure arranged, in use, to contact regions of the user&#39;s head, and opposing temporal connectors that are disposed on opposing sides of the user&#39;s head in use, and extending along the temporal regions of the user&#39;s head in use, to interconnect the rear support structure to the display unit. 
     In some forms, the rear support structure includes a hoop having an occipital portion and a parietal portion. In some forms, the hoop or at least one of the occipital and parietal portions may be resiliently extensible along at least a portion of its length. In some forms, the hoop is flexible along at least a portion of its length. In some forms, where the rear support structure is a hoop, the occipital portion may extend low on the user&#39;s head such that it resists upward movement (as a result of its location in contact with the occipital region of the head) and as such provides an anchor for the system. In some forms, the hoop is orientated in a generally upright plane (such upright plane including, as an example, the coronal plane). 
     In some forms, the rear support structure is disposed posterior to the otobasion superior of the user. 
     In some forms, the temporal connectors are rigid along at least a portion of their length. In some forms, the temporal connectors each comprise a temporal arm having an anterior end connected to the display unit and a posterior end connected to the rear support structure. In some forms, the temporal arm is rigid. In some forms, the posterior end of the temporal arm is disposed posterior to the otobasion superior of the user. 
     In some forms, at least one of the temporal connectors further comprises an adjustment mechanism for adjustment of the positioning and stabilising structure to fit different size heads. In some forms, the adjustment mechanism is disposed at the connection between the posterior end of the temporal arm and the rear support structure. 
     In some forms, the rear support structure comprises a connection tab that connects to the temporal arm, and the adjustment mechanism allows for adjustment of the effective length of the connection tab. In some forms, a posterior end of the temporal arm incorporates an eyelet that is arranged to receive the connection tab, the adjustment mechanism comprising a releasable fastening arrangement to fasten the connection tab to the temporal arm. In some forms, the releasable fastening arrangement may be arranged to secure a free end of the connection tab back onto a proximal portion of the connection tab. The releasable fastening arrangement may take other forms, such as clips or retainers that allow a friction, interference, snap or other mechanical fixing arrangement. 
     In some forms, the positioning and stabilising structure may further include a forehead support connector that extends generally in the direction of the sagittal plane and connects the rear support structure to a superior edge region of the display unit. In some forms, the forehead support connector may comprise a strap. In some forms, the strap of the forehead support connector may be resiliently extensible along at least a portion of its length. In some forms, the strap of the forehead support connector may be flexible along at least a portion of its length. 
     In some forms, the forehead support connector may further include an adjustment mechanism for adjustment of the positioning and stabilising structure to fit different size heads. In some forms, the adjustment mechanism may adjust the effective length of the strap of the forehead support connector when the forehead support connector is in that form. 
     In some forms, the forehead support connector further comprises a forehead support rigidiser that provides rigidification to a portion of the forehead support connector. In some forms, the forehead support rigidiser provides rigidification to a portion of the forehead support connector located along the frontal region of the user&#39;s head. The extent and positioning of the forehead support rigidiser may assist in correct positioning of the display unit and relieve pressure being applied to the zygomatic bone of the user. In some forms, the forehead support rigidiser may be adjustable (angularly or translational) on other components of the forehead support connector, such as the strap of the forehead support connector, to allow fine positioning of the head-mounted display unit and assist in improving user comfort and fit. 
     In some forms, the positioning and stabilising structure further includes additional rigidisers which may bridge the rear support structure and the temporal connectors. In some forms, these additional rigidisers may assist in controlling the movement of the display unit about the rear support structure to further stabilise and support the system. In some forms, these additional rigidisers may limit hinging movement at the connection of the temporal connectors to the rear support structure. In some forms, these additional rigidisers may also extend through along the occipital region of the rear support structure to further anchor the display unit in its correct operational position. In some forms, these additional rigidisers may be adjustable (angularly or translational) on other components of the forehead support connector to further assist in comfort, adjustability, and fit. 
     In some forms, the positioning and stabilising structure may allow for upward, e.g., superior, pivoting movement of the display unit to allow for movement of the display unit to a non-operational position without removal of the positional and stabilising structure (e.g., flip-up version). In some forms, this pivoting arrangement may provide a release mechanism at the forehead support connector and/or provide limited hinging regions at the temporal connectors. 
     The positioning and stabilising structure in any form described above may be incorporated in a hood or other head wear either integrated therein or releasably connected thereto. The positional and stabilising structure may also include other components integrated therein such as audio, tactile (haptic) stimulation or feedback. 
     An aspect of the present technology relates to a head-mounted display system including a head-mounted display unit and a positioning and stabilising structure structured and arranged to hold the head-mounted display unit in an operational position over a user&#39;s face in use. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user&#39;s head and at least one connector structured and arranged to interconnect the rear support structure to the head-mounted display unit. The rear support structure is in the form of a hoop comprising an occipital portion configured and arranged engage the user&#39;s head along the occipital bone (e.g., along a portion of the occipital bone adjacent a junction where the neck muscles attach to the occipital bone) in use. 
     An aspect of the present technology relates to a positioning and stabilising structure to hold a head-mounted display unit in an operational position over a user&#39;s face. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user&#39;s head and at least one connector structured and arranged to interconnect the rear support structure to the head-mounted display unit. The rear support structure is in the form of a hoop comprising an occipital portion configured and arranged engage the user&#39;s head along the occipital bone (e.g., along a portion of the occipital bone adjacent a junction where the neck muscles attach to the occipital bone) in use. 
     An aspect of the present technology relates to a positioning and stabilising structure to hold a head-mounted display unit in an operational position over a user&#39;s face. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user&#39;s head and opposing temporal connectors structured and arranged to interconnect the rear support structure to the head-mounted display unit. The opposing temporal connectors are adapted to be disposed on opposing sides of the user&#39;s head and extend along the temporal regions of the user&#39;s head. The rear support structure is in the form of a hoop comprising an occipital portion configured and arranged engage the user&#39;s head along the occipital bone (e.g., along a portion of the occipital bone adjacent a junction where the neck muscles attach to the occipital bone) in use. 
     An aspect of the present technology relates to a head-mounted display system including a head-mounted display unit and a positioning and stabilising structure structured and arranged to hold the head-mounted display unit in an operational position over a user&#39;s face in use. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user&#39;s head and at least one connector structured and arranged to interconnect the rear support structure to the head-mounted display unit. At least the rear support structure comprises a textile material configured to conform to the posterior regions of the user&#39;s head. 
     An aspect of the present technology relates to a positioning and stabilising structure to hold a head-mounted display unit in an operational position over a user&#39;s face. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user&#39;s head and at least one connector structured and arranged to interconnect the rear support structure to the head-mounted display unit. At least the rear support structure comprises a textile material configured to conform to the posterior regions of a user&#39;s head. 
     An aspect of the present technology relates to a head-mounted display system including a head-mounted display unit and a positioning and stabilising structure structured and arranged to hold the head-mounted display unit in an operational position over a user&#39;s face in use. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user&#39;s head and opposing temporal connectors structured and arranged to interconnect the rear support structure to the head-mounted display unit, the opposing temporal connectors adapted to be disposed on opposing sides of the user&#39;s head and extend along the temporal regions of the user&#39;s head. At least the rear support structure comprises a textile material configured to conform to the posterior regions of the user&#39;s head. 
     An aspect of the present technology relates to a positioning and stabilising structure to hold a head-mounted display unit in an operational position over a user&#39;s face. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user&#39;s head and opposing temporal connectors structured and arranged to interconnect the rear support structure to the head-mounted display unit, the opposing temporal connectors adapted to be disposed on opposing sides of the user&#39;s head and extend along the temporal regions of the user&#39;s head. At least the rear support structure comprises a textile material configured to conform to the posterior regions of the user&#39;s head. 
     An aspect of the present technology relates to a positioning and stabilising structure to hold a head-mounted display unit in an operational position over a user&#39;s face. The positioning and stabilising structure includes a rear support structure adapted to contact regions of a user&#39;s head and at least one connector or strap structured and arranged to interconnect the rear support structure to the head-mounted display unit. 
     The positioning and stabilizing structure and/or the head-mounted display unit may be configured to help distribute contact forces from more sensitive regions of the user&#39;s face (forehead, upper cheeks below the eyes) to regions that are better suited to oppose a force applied. For example, the rear support structure may be sufficiently flexible to evenly and snugly engage the rear of the user&#39;s head, e.g., anchor on the occipital bone but above the neck muscles, and/or have increased rigidity in one or more portions to better support the load of the head-mounted display unit in a comfortable and sustainable manner. For example, the rear support structure may be made of a strap material (e.g., textile) that is breathable and flexible to allow it to adjust to the shape and/or size of the user&#39;s head, where certain parts of the strap material may be rigidized and/or a rigid portion added (e.g., sewn, laminated, clipped, inserted into a pocket, overmolded, and/or ultrasonically welded into place) to help maintain stability and offset a portion of the force applied to a portion of the patient&#39;s face via the head-mounted display unit. 
     In an example, the positioning and stabilizing structure and/or the head-mounted display unit may be configured to cooperatively work together to reduce the force applied to the patient&#39;s forehead and/or cheek bones, by effectively transferring those forces to the rear support and/or to the at least one connector or strap(s), and/or by simply distributing the forces from the head-mounted display unit more evenly along the head-mounted display unit and/or the rear support structure and/or the at least one connector or strap(s). This is done in a way that adds comfort and/or stability, e.g., to prevent the head-mounted unit from sliding down the user&#39;s face/forehead. 
     Another aspect of the present technology relates to a head mounted-display system or assembly including a positional and stabilising structure in any form described above, and a display unit connected thereto. 
     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 in various manners and also constitute additional aspects or sub-aspects of the present technology. 
     Other features of the technology will be apparent from consideration of the information contained in the following detailed description, abstract, drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG.  1 A  is a side view of a head with several features of surface anatomy identified including otobasion superior and otobasion inferior. The approximate location of the Frankfort horizontal is indicated. The coronal plane is also indicated. Also indicated are the directions superior &amp; inferior, and anterior &amp; posterior. 
         FIG.  1 B  shows a front view of the bones of a skull including the frontal, nasal and zygomatic bones. 
         FIG.  1 C  shows a lateral view of a skull with the outline of the surface of a head, as well as several muscles. Exemplary bones shown include frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal, temporal and occipital. 
         FIGS.  2 A to  2 C  are respective side, front and top views of a head-mounted display assembly in-use according to a first example of the present technology. 
         FIG.  2 D  is a cross-sectional view of a temporal arm of the head-mounted display assembly of  FIGS.  2 A to  2 C  according to an example of the present technology. 
         FIG.  2 E  is a cross-sectional view of a temporal arm of the head-mounted display assembly of  FIGS.  2 A to  2 C  according to another example of the present technology. 
         FIGS.  3 A to  3 C  are respective side, front and top views of a head-mounted display assembly in-use according to a second example of the present technology. 
         FIGS.  4 A to  4 C  are respective side, front and top views of a head-mounted display assembly in-use according to a third example of the present technology. 
         FIG.  5    is a side view of a head-mounted display assembly in-use according to a fourth example of the present technology. 
         FIGS.  6 A to  6 C  are respective side, rear and top views of a head-mounted display assembly in-use according to a variation of the fourth example of the present technology. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY 
     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. 
     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. 
       FIGS.  2 A to  2 C  show a support for a head-mounted display system or assembly  10  according to a first example of the present technology. The head-mounted display system  10  comprises a head-mounted display unit  12 , and a positioning and stabilising structure  14  (also referred to as a support and stabilising structure) to maintain or hold the display unit  12  in an operational position over a user&#39;s face in use. 
     The display unit  12  includes a user interface structure  13  constructed and arranged to be in opposing relation with the user&#39;s face. The user interface structure  13  extends about a display contained by the display unit housing  22 . The user interface structure  13  may extend about the display and define a viewing opening to the display. The user interface structure  13  extends around the user&#39;s eyes, and may engage (e.g., light sealing) with the user&#39;s face, e.g., along the user&#39;s nose, cheeks and/or forehead. 
     As described below, the head-mounted display system according to examples of the present technology is structured and arranged to provide a balanced system, i.e., not overly tight at any singular point along the user&#39;s head and/or face, while providing a perception of complete sealing around the user&#39;s eyes, i.e., to provide complete immersion in the use of virtual reality head-mounted displays. That is, the head-mounted display system according to examples of the present technology provides a more even fit that is structured and arranged to distribute pressure over more of the user&#39;s head to lessen hot spots or localised stress points. 
     Also, the head-mounted display system according to examples of the present technology comprises soft and flexible (e.g., elastic) materials (e.g., breathable material, e.g., textile-foam composite) structured and arranged to allow more conformity to the user&#39;s head and cushioning for comfort. In addition, the head-mounted display system according to examples of the present technology comprises simple adjustment mechanisms to facilitate adjustment while on the user&#39;s head and allow a wide fit range. 
     In the illustrated example of  FIGS.  2 A to  2 C , the positioning and stabilising structure  14  comprises a rear support structure  16  (also referred to as a rear support hoop) adapted to contact regions of a user&#39;s head (e.g., positionable at a crown of the user&#39;s head) and at least one connector structured and arranged to interconnect the rear support structure  16  to the head-mounted display unit  12 . In the illustrated example, the at least one connector comprises opposing temporal connectors  18  disposed on respective sides of the user&#39;s head that interconnect the rear support hoop  16  to respective posterior edge regions  20  of the display unit housing  22  of the display unit  12 , and a forehead support connector  24  that extends across the frontal bone of the user to interconnect the rear support hoop  16  with a superior edge region  21  of the display unit housing  22 . However, it should be appreciated that more or less connectors may be provided to interconnect the rear support structure  16  to the head-mounted display unit  12 . 
     Each of the opposing temporal connectors  18  comprises a temporal arm  26 . Each temporal arm  26  includes an anterior end  28  mounted to the respective posterior edge region  20  of the display unit housing  22  and a posterior end  30  that forms part of a releasable coupling to connect the temporal arm  26  to the rear support hoop  16 . 
     Each temporal arm  26  comprises a rigidiser  32 , a textile component  34  and a tab  36  arranged at the posterior end  30  for connecting to the rear support hoop  16 . In an example, a portion of each of the temporal arms  26 , in-use, is in contact with a region of the user&#39;s head proximal to the otobasion superior, i.e., above the user&#39;s ear. In an example, the temporal arms  26  are arranged in-use to run generally along or parallel to the Frankfort Horizontal plane of the head and superior to the zygomatic bone, i.e., above the user&#39;s cheek bone. 
     In one form, the rigidiser  32  may be encapsulated within the textile component  34  of each temporal arm  26 . For example,  FIG.  2 D  shows an example of the textile component  34  in the form of a cover configured to encapsulate the rigidiser  32 . In this example, the textile component  34  includes a face contacting side arranged on one side of the rigidiser  32  that can provide a soft, face contacting surface  35  adapted to contact the patient&#39;s face in use. In some alternative forms, the rigidiser  32  may be stitched or otherwise attached (e.g., overmolded) to the textile component  34 , or the textile component can be made of materials that can be selectively rigidised by heat treatment (e.g., heat treatment). For example,  FIG.  2 E  shows an example of the textile component  34  attached to a face contacting side of the rigidiser  32  that can provide a soft, face contacting surface  35  adapted to contact the patient&#39;s face in use. In an example, the textile component  34  may comprise a textile material or a textile-foam composite (e.g., breathable material, e.g., multi-layered construction including an outer textile layer and an inner foam layer) to provide a soft support for the rigidiser  32  to cushion against the user&#39;s head for optimised comfort. The rigidiser  32  can allow each temporal arm  26  to retain an in-use shape and configuration when not worn by a user. Advantageously, maintaining the temporal arms  26  in the in-use state prior to use may prevent or limit distortion whilst the user is donning the positioning and stabilising structure  14  and allow a user to quickly fit or wear the display system  10 . 
     In an example, the rigidiser  32  can be made from a rigid material, e.g., hytrel (thermoplastic polyester elastomer). As such, the rigidiser  32  (or the temporal connector  18  or the temporal arm  26 ) is rigid along at least a portion of its length. The rigid nature, i.e., inextensibility, of the rigidiser  32  of each temporal arm  26  limits the magnitude of elongation or deformation of the temporal arm  26  while in-use. Advantageously, this configuration enables a more effective, i.e., direct, translation of tension through the temporal arm  26 . In an example, the rigidiser  32  may be more rigid than the rear support hoop  16  and/or connection straps  42  (e.g., formed from an elastic and/or textile material). Consequently, the temporal arm  26  of each opposing temporal connector  18  may be more rigid than the other parts of the positioning and stabilising structure  14 , such as more rigid than the rear support hoop  16  and/or connection straps  42 . The temporal arm  26  (or temporal connector  18 ) may be more rigid along at least a portion of its length than the other parts of the positioning and stabilising structure  14 , such as more rigid than the rear support hoop  16  and/or connection straps  42 . For example, in contrast to the rigidiser  32  (or the temporal connector  18  or the temporal arm  26 ), the rear support hoop  16  and/or connection straps  42  may be stretchable to a desired length, i.e., resiliently extensible along at least a portion of its length. 
     In an example, the rigidiser  32  may be structurally rigid or stiff to resist bending deformation vertically up and down alongside the user&#39;s face, but may allow bending deformation towards and away from the user&#39;s face (e.g., to adjust for varying facial width). In an example, the rigidiser  32  may be structurally rigid or stiff to resist deformation under twisting. In an example, the rigidiser  32  may be structurally rigid or stiff to maintain a preformed shape. 
     In an example, the rigidiser  32  forms a lever-arm, i.e., a means to pivot, about the rear support hoop  16 . Advantageously, the rear support hoop  16  can provide an anchor point for the positioning and stabilising structure  14 . The rigidiser  32  may articulate about the anchor point of the rear support hoop  16  to enable the forehead support connector  24  to raise or lower the position of the display unit  12  relative to the user&#39;s nose. Advantageously, this configuration can minimise the magnitude of clamping pressure to stabilise the display unit  12  on the user&#39;s head. 
     In an example, the thickness and/or width of the temporal arm  26  may vary along at least a portion of its length, e.g., temporal arm  26  may include wider and thinner sections along its length to facilitate connection and to distribute load. 
     In the illustrated example, the rear support structure or hoop  16  is in the form of a hoop having a ring-like form (similar to the ring-like form of rear support hoop  316  shown in the  FIG.  6 B  example) and is arranged to have a three-dimensional contour curve to fit or conform to the shape of the rear of the user&#39;s head, e.g., a user&#39;s crown. The rear support hoop  16  comprises a parietal portion or parietal strap portion  38 , adapted to be in proximity to the parietal bone of the user&#39;s head in use, and an occipital portion or occipital strap portion  40 , adapted to be in proximity to the occipital bone of the user&#39;s head in use. In an example, the occipital portion  40  is preferably arranged along a portion of the occipital bone in use, e.g., along a portion of the occipital bone adjacent or near a junction where the neck muscles attach, and the parietal portion  38  is preferably arranged rearward of the coronal plane in use. In an example, the occipital portion  40  is adapted to be positioned along a portion of the occipital bone just above a junction where the neck muscles attach to the occipital bone. The junction may also be referred to as the external occipital protuberance (EOP). However, the exact location of the occipital portion  40  on the user&#39;s head may vary depending on the size and shape of the user&#39;s head with which it is being used, e.g., the occipital portion  40  may be positioned adjacent to, just above, or just below a portion of the occipital bone where the neck muscles attach. In an example, the occipital portion  40  may be arranged beneath or underneath the occipital bone near the junction where the neck muscles attach. This hoop-like arrangement (e.g., circular or ovular or part circular/oval or C-shaped) of the rear support hoop  16  anchors the positioning and stabilising structure  14  around the rear or rear bump of the user&#39;s head, which provides an effective support structure to hold weight (i.e., the display unit) at the front of the user&#39;s head. The rear support hoop  16  may be formed from an elastic material, which elasticity may be used to stretch the hoop and securely hold the rear support hoop  16  in position. 
     The rear support hoop  16  further comprises opposing connection straps or tabs  42 . The straps  42  are adjustable and operate to change the distance between the rear support hoop  16  and the display unit housing  22  of the display unit  12 . Each of the straps  42 , in use, is threaded through an eyelet  44  in the tab  36  of a respective temporal arm  26 . The length of each strap  42  through the tab  36  of a respective temporal connector  18  may be adjusted by pulling more or less of the strap  42  through a respective eyelet  44 . The strap  42  may be secured to itself after passing through the eyelet  44  in the tab  36 , for example, with hook-and-loop fastening means, which allows fine or micro adjustment of the straps for comfort and fit (e.g., tightness). Therefore, the distance between the rear support hoop  16  and the display unit housing  22  may be adjusted to fit around different head sizes. Such adjustable strap arrangement also allows adjustment while the system is on the user&#39;s head, e.g., user can pull straps  42  to posteriorly tighten. 
     In an example, the thickness and/or width of the rear support hoop  16  and/or the straps  42  may vary along at least a portion of its length. For example, the rear support loop  16  may include wider and thinner sections along its length, e.g., wider sections adjacent the straps  42  to facilitate connection to the temporal arms  26  and to distribute load. Also the straps  42  may be thinner along it free end to facilitate threading through the eyelet  44  in the respective temporal arm  26 . 
     In an example, the rear support hoop  16  is orientated in a generally vertical direction, i.e., arranged in a vertical plane generally parallel to the coronal plane. This arrangement of the rear support hoop  16  appropriately orients the rear support hoop  16  at the crown of the user&#39;s head to support the transverse, i.e., horizontal, tension applied by the connection straps  42  and support the weight of the display unit  12 , in-use, at the anterior of the user&#39;s head. 
     The rear support hoop  16  and connection straps  42  may be formed from an elastic and/or textile material to assist conforming to the shape of a user&#39;s head, e.g. rear support hoop  16  and connection straps  42  provide stretch capacity. Also, such elastic material at the back of the user&#39;s head may allow easier lifting of the display unit  12  away from the user&#39;s face in use, e.g., move the display unit  12  away from the user&#39;s eyes to talk to someone while the positioning and stabilising structure  14  remains on the user&#39;s head. For example, the support hoop  16  may be a neoprene material, or other textile-foam composite (e.g., breathable material, e.g., multi-layered construction including at an outer textile layer and an inner foam layer), or spacer fabric. Advantageously, textiles can provide a soft support structure to stabilise the display unit  12  on a user&#39;s head and allow the positioning and stabilising structure  14  to cushion against the user&#39;s head for optimised comfort. 
     The forehead support connector  24  of the positioning and stabilising structure  14  comprises a forehead support strap  48  arranged to run generally along or parallel to the sagittal plane of the user&#39;s head. The forehead support strap  48  is adapted to connect between the superior edge region  21  of the display unit housing  22  and the parietal portion  38  of the rear support hoop  16 . In an example, the strap  48  can be non-adjustably connected, e.g., welded, to the parietal portion  38 , and the strap  48  can be adjustably connected to the display unit housing  22  by an adjustment mechanism  50 . 
     The forehead support strap  48  is adjustable to enable dimensional control of the forehead support connector  24 . As best shown in  FIG.  2 C , an end portion or tab portion  54  of the forehead support strap  48 , in use, is threaded through a forehead support hole  52  in the superior edge region  21  of the display unit  12 . The forehead support strap  48  may be secured to itself after passing through the hole  52  in the display unit  12 , for example, with hook-and-loop fastening means, which allows fine or micro adjustment of the straps for comfort and fit (e.g., tightness). In an example, the forehead support strap  48  may comprise a similar material to rear support hoop  16  and/or the connection straps  42 , e.g., textile-foam composite (e.g., breathable material, e.g., multi-layered construction including at an outer textile layer and an inner foam layer). 
     The forehead support connector  24  supports the weight of the display unit  12 . The length of the forehead support strap  48  between the superior edge region  21  of the display unit  12  and the parietal portion  38  of the rear support hoop  16  may be adjusted by pulling more or less of the strap  48  through the hole  52 . Therefore, the forehead support strap  48  is able to be adjusted to raise or lower the position of the display unit  12  relative to the user&#39;s nose, e.g., adjust to angle or lift the display unit  12  relative to the user&#39;s face. Advantageously, this adjustment can move the display unit housing  22  away from the user&#39;s nose to relieve pressure felt on the face, nose, and/or cheeks. The forehead support connector  24  secures the display unit  12  in position so that the display unit does not slide downwards or laterally on the user&#39;s head. 
     In an example, the thickness and/or width of the forehead support strap  48  may vary along at least a portion of its length, e.g., forehead support strap  48  may include wider and thinner sections along its length to facilitate connection and to distribute load. 
     In an example, the adjustment mechanism  50  is positioned, in use, out of contact with a user&#39;s frontal bone region. 
     In an alternative example, the positioning and stabilising structure  14  does not include a forehead support connector  24 /forehead support strap  48 , e.g., see example of  FIGS.  4 A to  4 C . 
       FIGS.  3 A to  3 C  show a support for a head-mounted display system or assembly  110  according to a second example of the present technology. In  FIGS.  3 A to  3 C , like reference numerals denote similar or like parts to  FIGS.  2 A to  2 C  with the addition of 100 to allow distinguishing between examples, e.g., display unit  112 , user interface structure  113 , positioning and stabilizing structure  114 , rear support hoop  116 , temporal connector  118 , posterior edge region  120 , display unit housing  122 , forehead support connector  124 , temporal arm  126 , parietal portion  138 , occipital portion  140 , connection straps  142 , forehead support strap  148 , adjustment mechanism  150 , forehead support hole  152 , end portion  154 . Referring to  FIG.  3 C , the forehead support connector  124  may further comprise a forehead support rigidiser  156 . The forehead support rigidiser  156  can provide further stabilisation and support for the display unit  112  above the user&#39;s nose and cheeks, i.e., relieve pressure on the user&#39;s nose and cheeks. The forehead support rigidiser  156  can be connected to the superior edge region  121  and form at least part of the forehead support hole  152  to receive an end portion or tab portion  154  of the forehead support strap  148  for dimensional adjustment of the positioning and stabilising structure  114 . As illustrated the forehead support strap  148  is arranged beneath the forehead support rigidiser  156  for comfort and load distribution. 
     In some forms, the adjustment mechanism  150  may further comprise an angle adjustment mechanism (not shown) for easy lifting of the visor from an in-use position to a stowed position, i.e., not in-use. 
     In an example, the system may be structured and arranged to redistribute one or more components from the display unit to the positioning and stabilizing structure, e.g., to redistribute weight from the display unit to the positioning and stabilizing structure. For example, the forehead support rigidiser  156  and/or forehead support strap  148  may be used to at least partially support one or more non-location essential electrical components, e.g., batteries, hard drive storage, to shift weight from the front of the user&#39;s head to a more central location, i.e., to counterbalance weight of the display unit. In alternative examples, one or more components from the display unit may be at least partially supported by the rear support hoop  116  and/or temporal connectors  118  to redistribute weight. 
       FIGS.  4 A to  4 C  show a support for a head-mounted display system or assembly  210  according to a third example of the present technology. In  FIGS.  4 A to  4 C , like reference numerals denote similar or like parts to  FIGS.  2 A to  2 C  with the addition of 200 to allow distinguishing between examples, e.g., display unit  212 , user interface structure  213 , positioning and stabilizing structure  214 , rear support hoop  216 , temporal connector  218 , posterior edge region  220 , display unit housing  222 , temporal arm  226 , parietal portion  238 , occipital portion  240 , connection straps  242 . In the third example, the support for a head-mounted display assembly  210  does not comprise a forehead support, i.e., the display unit  212  is supported by a positioning and stabilizing structure  214  without any forehead support connector or forehead support straps. 
       FIG.  5    shows a support for a head-mounted display system or assembly  310  according to a fourth example of the present technology. In  FIG.  5   , like reference numerals denote similar or like parts to  FIGS.  2 A to  2 C  with the addition of 300 to allowing distinguishing between examples, e.g., display unit  312 , user interface structure  313 , positioning and stabilizing structure  314 , rear support hoop  316 , temporal connector  318 , display unit housing  322 , forehead support connector  324 , temporal arm  326 , rigidiser  332 , parietal portion  338 , occipital portion  340 , forehead support strap  348 . In the fourth example, the support for a head-mounted display system  310  comprises opposing temporal connectors  318  each having a temporal arm  326  with an extended rigidiser  358 . Each extended rigidiser  358  may extend from the respective temporal arm  326  to the rear support hoop  316  to enhance support of the display unit  312 , in use. Each extended rigidiser  358  may extend along a portion of the rear support hoop  316  and may extend into one or both of the parietal portion  338  and the occipital portion  340 . For example, each extended rigidiser  358  may comprise a Y-shaped form as shown in  FIG.  5    that extends into both the parietal portion  338  and the occipital portion  340 . Alternatively, each extended rigidiser  358  may only extend into one of the parietal portion  338  and the occipital portion  340 , e.g., only extend along the occipital portion  340  as shown in  FIG.  6 A  discussed below. In the example of  FIG.  5   , the parietal and occipital portions of the extended arms of the rigidiser  358  are provided along the parietal portion  338  and occipital portion  340  of the rear support hoop  316  positioned proximal to the parietal and occipital bones of the user&#39;s head to support respective portions of the rear support hoop  316 . 
     The extended rigidisers  358  increase the length of the temporal connectors  318  so as to increase the lever-arm moment created about the rear support hoop  316 . In use, the larger lever-arm extends the moment of inertia further rearward of the user&#39;s head when compared the first and second examples. Advantageously, this can provide more comfort to the user by decreasing the tension applied to the forehead support connector  324  to support the display unit  312 . 
     Additionally, the extended arms of the rigidiser  358  may provide a more even distribution of pressure on the user&#39;s head under the weight of the display unit  312  and any clamping force applied by tension induced in the positioning and stabilising structure  314 . 
     The extended arms of the rigidiser  358  can help prevent the rear support hoop  316  of the positioning and stabilising structure  314  from translating vertically upwards on the user&#39;s head when tensioning the forehead support connector  324 . The extended arms of the rigidiser  358  can more effectively secure the occipital portion  340  of the rear support hoop  316  along the corresponding occipital bone (e.g., along a portion of the occipital bone adjacent a junction where the neck muscles attach to the occipital bone) of the user&#39;s head. 
       FIGS.  6 A to  6 C  show a variation of the fourth example in  FIG.  5   . In this example, each of the temporal arms  326  comprises a biased extended rigidiser  360 . Each biased extended rigidiser  360  may extend from the respective temporal arm  326  to the occipital portion  340  of the rear support hoop  316 , i.e., to generally take a J-shaped form, so as to enhance support of the display unit  312 , in use. 
     The biased extended rigidisers  360  extend along a portion of the occipital bone, e.g., along a portion of the occipital bone adjacent a junction where the neck muscles attach to the occipital bone, to securely anchor the positioning and stabilising structure  314  so as to support the display unit  312  above the user&#39;s nose and cheek. 
     As best shown in  FIGS.  6 A and  6 B , medial and temporal adjustment mechanisms  362 ,  364  may be provided to the temporal arms  326  and the biased extended rigidisers  360 . The medial adjustment mechanism  362  can be mounted about the medial region of the occipital portion between opposed arms of the biased extended rigidisers  360 . In an example, the medial adjustment mechanism  362  may be in the form of a strap threaded through opposing holes  363  in respective posterior ends  368  of the opposing arms of the biased extended rigidisers  360  (see  FIG.  6 B ). The distance between the opposing arms of the rigidisers  360  can be controlled by pulling more or less of the strap  362  through the holes  363 . 
     The temporal adjustment mechanism  364  can be disposed on the temporal arm  326 , along the temporal region of the user&#39;s head. The temporal adjustment mechanism  364  can be adjustable and operate to change the distance between the biased extended rigidisers  360  and the display unit housing  322 . 
     The above-described head-mounted display systems provide alternative examples of the present technology structured and arranged to enhance comfort, fit range, usability, system architecture, use in a medical environment, and manufacturability. 
     The head-mounted display systems according to examples of the present technology provide enhanced comfort with minimised facial markings and pain from prolonged use. For example, comfort may be achieved by providing universal load distribution in which load is optimised on all contact surfaces by avoiding or minimising load on areas prone to discomfort and redistributing this load to areas able to comfortably bare the load, e.g., avoid or minimise load on the nasal bridge and sides of the nose and apply or redistribute this load to the top and/or rear of the head. Also, comfort may be achieved by providing regional load distribution in which load is evenly distributed by design and material selection in regions of the face where contact is unavoidable, e.g., contact points around the eyes may comprise compliant materials that evenly distribute load and avoid pain points/facial marking. In addition, comfort may be achieved by minimising weight as less weight in the overall system leads to less tension to position and maintain the system in the right configuration. In this regard, the head-mounted display systems according to examples of the present technology provide a minimalist design (e.g., low profile) to achieve fit range, comfort, and correct configuration, e.g., componentry optimised to minimize size and number of components to achieve function and use of robust and lightweight materials. 
     The head-mounted display systems according to examples of the present technology provide enhanced fit range or universal fit without trading off comfort, usability and cost. For example, fit range may be achieved by providing adjustability with geometry and material selection and adjustment mechanism. The components of the positioning and stabilising structure are designed and materials may be selected to provide desired force versus displacement, e.g., straps may stretch to a desired length under a predetermined force. The adjustment mechanism provides simplicity as sizing of the positioning and stabilising structure and associated straps may be manually adjusted and set, and componentry can be minimised while maximising ease of use, e.g., single handed adjustment of straps and alternative use of magnetic clips for connection. Also, the adjustment mechanism provides minimal size and weight which reduces the bulk of adjustment mechanisms with optimal materials and minimal components. Further, enhanced fit range may be achieved by anthropometrics in which adjustment range may be designed to fit the optimal anthropometric range of the desired market. 
     The head-mounted display systems according to examples of the present technology provide enhanced usability with low-touch simple set up solutions and low dexterity threshold solutions. For example, low-touch set up may be achieved with self-adjusting solutions including stretchable materials or simple mechanical actuation where only a few minor adjustments may be necessary for correct fit. Also, the system may include adjust and lock solutions to facilitate usability (i.e., set and forget), e.g., mechanisms to guide adjustment (e.g., magnets) and locking mechanisms to set adjustment (e.g., clips). Further, the system provides ease of use so that it is capable of adjustment when worn by a user with low-dexterity and/or minimal vision. 
     The head-mounted display systems according to examples of the present technology provide enhanced system architecture which optimises componentry location such that it minimises cost while maximising comfort, fit range and usability. For example, the system may provide enhanced weight distribution in which electrical and/or mechanical components are positioned in ideal locations from a comfort perspective. Also, the system may comprise modularity such that components may be selected or upgraded based on user preference, e.g., electrical component, face contacting cushions, straps, and/or ear buds may be selected based on preference. 
     The head-mounted display systems according to examples of the present technology enhance use in a medical environment. For example, the system may be biocompatible and/or cleanable with materials selected that are cleanable for re-use in a medical environment and/or pass biocompatibility requirements. 
     The head-mounted display systems according to examples of the present technology enhance manufacturability by providing mass producible solutions at low cost while maintaining high quality and functionality. 
     In the claims which follow and in the preceding description of examples of the present technology, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various examples of the present technology. 
     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 or examples. 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. 
     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. 
     REFERENCE SIGNS LIST 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Feature Item 
                 Number 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 head-mounted display system 
                 10 
               
               
                   
                 display unit 
                 12 
               
               
                   
                 user interface structure 
                 13 
               
               
                   
                 positioning and stabilising structure 
                 14 
               
               
                   
                 rear support hoop 
                 16 
               
               
                   
                 temporal connectors 
                 18 
               
               
                   
                 posterior edge region 
                 20 
               
               
                   
                 superior edge region 
                 21 
               
               
                   
                 display unit housing 
                 22 
               
               
                   
                 forehead support connector 
                 24 
               
               
                   
                 temporal arm 
                 26 
               
               
                   
                 anterior end 
                 28 
               
               
                   
                 posterior end 
                 30 
               
               
                   
                 rigidiser 
                 32 
               
               
                   
                 textile component 
                 34 
               
               
                   
                 face contacting surface 
                 35 
               
               
                   
                 tab 
                 36 
               
               
                   
                 parietal portion 
                 38 
               
               
                   
                 occipital portion 
                 40 
               
               
                   
                 connection straps 
                 42 
               
               
                   
                 eyelet 
                 44 
               
               
                   
                 forehead support strap 
                 48 
               
               
                   
                 adjustment mechanism 
                 50 
               
               
                   
                 forehead support hole 
                 52 
               
               
                   
                 tab portion 
                 54 
               
               
                   
                 head-mounted display system 
                 110 
               
               
                   
                 display unit 
                 112 
               
               
                   
                 user interface structure 
                 113 
               
               
                   
                 positioning and stabilising structure 
                 114 
               
               
                   
                 rear support hoop 
                 116 
               
               
                   
                 temporal connector 
                 118 
               
               
                   
                 posterior edge region 
                 120 
               
               
                   
                 superior edge region 
                 121 
               
               
                   
                 display unit housing 
                 122 
               
               
                   
                 forehead support connector 
                 124 
               
               
                   
                 temporal arm 
                 126 
               
               
                   
                 parietal portion 
                 138 
               
               
                   
                 occipital portion 
                 140 
               
               
                   
                 connection straps 
                 142 
               
               
                   
                 forehead support strap 
                 148 
               
               
                   
                 adjustment mechanism 
                 150 
               
               
                   
                 forehead support hole 
                 152 
               
               
                   
                 tab portion 
                 154 
               
               
                   
                 forehead support rigidiser 
                 156 
               
               
                   
                 head-mounted display system 
                 210 
               
               
                   
                 display unit 
                 212 
               
               
                   
                 user interface structure 
                 213 
               
               
                   
                 positioning and stabilising structure 
                 214 
               
               
                   
                 rear support hoop 
                 216 
               
               
                   
                 temporal connector 
                 218 
               
               
                   
                 posterior edge region 
                 220 
               
               
                   
                 display unit housing 
                 222 
               
               
                   
                 temporal arm 
                 226 
               
               
                   
                 parietal portion 
                 238 
               
               
                   
                 occipital portion 
                 240 
               
               
                   
                 connection straps 
                 242 
               
               
                   
                 head-mounted display system 
                 310 
               
               
                   
                 display unit 
                 312 
               
               
                   
                 user interface structure 
                 313 
               
               
                   
                 positioning and stabilising structure 
                 314 
               
               
                   
                 rear support hoop 
                 316 
               
               
                   
                 temporal connectors 
                 318 
               
               
                   
                 temporal connector 
                 318 
               
               
                   
                 display unit housing 
                 322 
               
               
                   
                 forehead support connector 
                 324 
               
               
                   
                 temporal arm 
                 326 
               
               
                   
                 rigidiser 
                 332 
               
               
                   
                 parietal portion 
                 338 
               
               
                   
                 occipital portion 
                 340 
               
               
                   
                 forehead support strap 
                 348 
               
               
                   
                 extended rigidiser 
                 358 
               
               
                   
                 biased extended rigidiser 
                 360 
               
               
                   
                 medial adjustment mechanism 
                 362 
               
               
                   
                 holes 
                 363 
               
               
                   
                 temporal adjustment mechanism 
                 364 
               
               
                   
                 posterior ends 
                 368