PATENT DOCUMENT

Publication Number: US-11782288-B2
Application Number: US-202017021387-A
Country: US
Kind Code: B2

Title: Head-mounted device with adjustment mechanism

Abstract:
A head-mounted device includes a first device portion and a second device portion. A first coupler portion of the first device portion is connectable to a second coupler portion of the second device portion to define a connected position in which the first device portion is connected to the second device portion and a disconnected position in which the first device portion is disconnected from the second device portion. A second adjuster portion of the second device portion causes a first adjuster portion of the first device portion to move a first optical module and a second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position.

Claims:
What is claimed is: 
     
       1. A head-mounted device, comprising:
 a first device portion that includes:
 a primary housing, 
 a first optical module, 
 a second optical module, 
 a first coupler portion that is connected to the primary housing, and 
 a first adjuster portion that is operable to move the first optical module and the second optical module with respect to the primary housing, the first adjuster portion including a first contact surface; and 
 
 a second device portion that includes:
 a secondary housing, 
 a face cushion that is connected to the secondary housing, 
 a second coupler portion that is connected to the secondary housing, and 
 a second adjuster portion that is operable to move the first optical module and the second optical module with respect to the primary housing, the second adjuster portion including a second contact surface, 
 
 wherein the first coupler portion of the first device portion is connectable to the second coupler portion of the second device portion to define a connected position in which the first device portion is connected to the second device portion and a disconnected position in which the first device portion is disconnected from the second device portion, and 
 wherein movement of the first device portion and the second device portion from the disconnected position to the connected position causes the second contact surface to engage the first contact surface to transfer a force from the second contact surface to the first contact surface to cause movement of the first adjuster portion and a corresponding movement of the first optical module and the second optical module. 
 
     
     
       2. The head-mounted device of  claim 1 , wherein the contact surfaces of the second adjuster portion are located laterally outward relative to the first optical module and the second optical module. 
     
     
       3. The head-mounted device of  claim 1 , wherein the contact surfaces of the second adjuster portion are located laterally inward relative to the first optical module and the second optical module. 
     
     
       4. The head-mounted device of  claim 1 , wherein the second adjuster portion includes a wedge that engages the first adjuster portion to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     
     
       5. The head-mounted device of  claim 1 , wherein the second adjuster portion includes annular contact surfaces that engage the first optical module and the second optical module to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     
     
       6. The head-mounted device of  claim 1 , wherein the first adjuster portion includes a rail, wherein the first optical module and the second optical module are slidably mounted on the rail. 
     
     
       7. The head-mounted device of  claim 1 , wherein the first adjuster portion includes springs that define an initial position for the first optical module and the second optical module in the disconnected position. 
     
     
       8. The head-mounted device of  claim 1 , wherein the first adjuster portion includes cams that cause movement of the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     
     
       9. The head-mounted device of  claim 1 , wherein the second adjuster portion includes stop surfaces that allow the first optical module and the second optical module to move to an adjusted position in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     
     
       10. The head-mounted device of  claim 1 , wherein the first adjuster portion includes a first group of magnetic connector components, the second adjuster portion includes a second group of magnetic connector components, and magnetic attraction of the first group of magnetic connector components to the second group of magnetic connector components causes the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     
     
       11. The head-mounted device of  claim 1 , wherein the first optical module and the second optical module are connected to the primary housing by an elastic support structure. 
     
     
       12. The head-mounted device of  claim 1 , wherein the first adjuster portion includes pneumatic actuators. 
     
     
       13. The head-mounted device of  claim 1 , wherein the first adjuster portion allows manual adjustment of the first optical module and the second optical module, and the second adjuster portion includes stop surfaces. 
     
     
       14. The head-mounted device of  claim 1 , wherein the first adjuster portion includes flexible connectors that are operable to move the first optical module and the second optical module, the flexible connectors are tensioned when the head-mounted device is worn by a user, and second adjuster portion includes stop surfaces. 
     
     
       15. The head-mounted device of  claim 1 , wherein the first adjuster portion includes a gross adjustment stage and a fine adjustment stage. 
     
     
       16. A head-mounted device, comprising:
 a first device portion that includes:
 a primary housing, 
 a first optical module, 
 a second optical module, 
 a first adjuster portion that is operable to move the first optical module and the second optical module with respect to the primary housing; and 
 
 a second device portion that includes:
 a secondary housing, 
 a second adjuster portion that is operable to move the first optical module and the second optical module with respect to the primary housing, 
 
 wherein the first device portion is connectable to the second device portion to define a connected position and a disconnected position, and 
 wherein the second adjuster portion includes a wedge that engages the first adjuster portion to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
 
     
     
       17. The head-mounted device of  claim 16 , wherein the wedge includes contact surfaces that engage contact surfaces of the first adjuster portion to cause the first adjuster portion to move the first optical module and the second optical module. 
     
     
       18. A head-mounted device, comprising:
 a first device portion that includes:
 a first optical module, 
 a second optical module, 
 a first adjuster portion that is operable to move the first optical module and the second optical module; and 
 
 a second device portion that includes:
 a second adjuster portion that is operable to move the first optical module and the second optical module, 
 
 wherein the first device portion is connectable to the second device portion to define a connected position and a disconnected position, and 
 wherein the second adjuster portion includes stop surfaces configured to engage the first optical module and the second optical module to cease movement of the first optical module and the second optical module at an adjusted position in response to movement of the first device portion and the second device portion from the disconnected position to the connected position, wherein positions of the stop surfaces on the second adjuster portion are adjustable to change the adjusted position. 
 
     
     
       19. The head-mounted device of  claim 17 , wherein the contact surfaces of the wedge are located laterally outward relative to the first optical module and the second optical module. 
     
     
       20. The head-mounted device of  claim 17 , wherein the contact surfaces of the wedge are located laterally inward relative to the first optical module and the second optical module. 
     
     
       21. The head-mounted device of  claim 17 , wherein the second adjuster portion includes stop surfaces that allow the first optical module and the second optical module to move to an adjusted position in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     
     
       22. The head-mounted device of  claim 18 , wherein the second adjuster portion includes contact surfaces that engage contact surfaces of the first adjuster portion to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     
     
       23. The head-mounted device of  claim 22 , wherein the contact surfaces of the second adjuster portion are located laterally outward relative to the first optical module and the second optical module. 
     
     
       24. The head-mounted device of  claim 22 , wherein the contact surfaces of the second adjuster portion are located laterally inward relative to the first optical module and the second optical module. 
     
     
       25. The head-mounted device of  claim 18 , wherein the second adjuster portion includes a wedge that engages the first adjuster portion to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/900,895, filed on Sep. 16, 2019, the content of which is hereby incorporated by reference herein in its entirety for all purposes. 
    
    
     FIELD 
     The present disclosure relates generally to the field of head-mounted devices. 
     BACKGROUND 
     Head-mounted devices that display computer-generated reality content include display devices and optics that guide light from the display devices to a user&#39;s eyes. Typically, two lenses are included to display slightly different images to each of the user&#39;s eyes in accordance with stereoscopic vision techniques. An adjustment mechanism may be included to allow the user to change the distance between the two lenses so that the lenses are approximately aligned with respect to the user&#39;s eyes. 
     SUMMARY 
     A first aspect of the disclosure is a head-mounted device that has a first device portion and a second device portion. The first device portion includes a primary housing, a first optical module, a second optical module, a first coupler portion that is connected to the primary housing, and a first adjuster portion that is operable to move the first optical module and the second optical module with respect to the primary housing. The second device portion includes a secondary housing, a face cushion that is connected to the secondary housing, a second coupler portion that is connected to the secondary housing, and a second adjuster portion that is operable to move the first optical module and the second optical module with respect to the primary housing. The first coupler portion of the first device portion is connectable to the second coupler portion of the second device portion to define a connected position in which the first device portion is connected to the second device portion and a disconnected position in which the first device portion is disconnected from the second device portion. The second adjuster portion causes the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the second adjuster portion includes contact surfaces that engage contact surfaces of the first adjuster portion to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. In some implementations of the head-mounted device according to the first aspect of the disclosure, the contact surfaces of the second adjuster portion are located laterally outward relative to the first optical module and the second optical module. In some implementations of the head-mounted device according to the first aspect of the disclosure, the contact surfaces of the second adjuster portion are located laterally inward relative to the first optical module and the second optical module. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the second adjuster portion includes a wedge that engages the first adjuster portion to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the second adjuster portion includes annular contact surfaces that engage the first optical module and the second optical module to cause the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion includes a rail, wherein the first optical module and the second optical module are slidably mounted on the rail. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion includes springs that define an initial position for the first optical module and the second optical module in the disconnected position. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion includes cams that cause movement of the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the second adjuster portion includes stop surfaces that allow the first optical module and the second optical module to move to an adjusted position in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion includes a first group of magnetic connector components, the second adjuster portion includes a second group of magnetic connector components, and magnetic attraction of the first group of magnetic connector components to the second group of magnetic connector components causes the first adjuster portion to move the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first optical module and the second optical module are connected to the primary housing by an elastic support structure. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion includes pneumatic actuators. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion allows manual adjustment of the first optical module and the second optical module, and the second adjuster portion includes stop surfaces. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion includes flexible connectors that are operable to move the first optical module and the second optical module, the flexible connectors are tensioned when the head-mounted device is worn by a user, and second adjuster portion includes stop surfaces. 
     In some implementations of the head-mounted device according to the first aspect of the disclosure, the first adjuster portion includes a gross adjustment stage and a fine adjustment stage. 
     A second aspect of the disclosure is a head-mounted device that includes a first device portion and a second device portion. The first device portion includes a primary housing, electrical components located in the primary housing, and a first coupler portion that is connected to the primary housing. The second device portion includes a secondary housing, a first optical module that is in the secondary housing, a second optical module that is in the secondary housing, a face cushion that is connected to the secondary housing, a second coupler portion that is connected to the secondary housing, and an adjustment assembly that is operable to move the first optical module and the second optical module with respect to the secondary housing. The first coupler portion of the first device portion is connectable to the second coupler portion of the second device portion to define a connected position in which the first device portion is connected to the second device portion and a disconnected position in which the first device portion is disconnected from the second device portion. 
     In some implementations of the head-mounted device according to the second aspect of the disclosure, the first optical module and the second optical module each include a display device and an optical system. 
     In some implementations of the head-mounted device according to the second aspect of the disclosure, the electrical components of the first device portion include a processor, a memory, a storage device, a communications device, sensors, and a power source. 
     In some implementations of the head-mounted device according to the second aspect of the disclosure, adjustment assembly includes an interpupillary distance adjustment stage, a vertical adjustment stage, and an eye relief adjustment stage. 
     A third aspect of the disclosure is a head-mounted device that includes a first device portion and a second device portion. The first device portion includes a primary housing, a first optical module, a second optical module, a first coupler portion that is connected to the primary housing, and an adjustment assembly that is operable to move the first optical module and the second optical module with respect to the primary housing. The second device portion includes a secondary housing, a face cushion that is connected to the secondary housing, a second coupler portion that is connected to the secondary housing, and an adjustment indicator. The first coupler portion of the first device portion is connectable to the second coupler portion of the second device portion to define a connected position in which the first device portion is connected to the second device portion and a disconnected position in which the first device portion is disconnected from the second device portion. The adjustment assembly moves the first optical module and the second optical module in response to movement of the first device portion and the second device portion from the disconnected position to the connected position using information obtained from the adjustment indicator of the second device portion. 
     In some implementations of the head-mounted device according to the second aspect of the disclosure, the information obtained from the adjustment indicator includes information describing an interpupillary distance setting. 
     In some implementations of the head-mounted device according to the second aspect of the disclosure, the adjustment indicator includes an information storage device and transmits the information to the adjustment assembly using wireless communication. 
     In some implementations of the head-mounted device according to the second aspect of the disclosure, the adjustment indicator includes indicia that are readable by the adjustment assembly. In some implementations of the head-mounted device according to the second aspect of the disclosure, the adjustment assembly is configured to read the indicia by obtaining images of the indicia. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram that shows an example of a hardware configuration for a head-mounted device that includes a first device portion and a second device portion. 
         FIG.  2    is an illustration that shows an example implementation of a left optical module of the first device portion of the head-mounted device. 
         FIG.  3    is a top-down cross-section illustration that shows a first example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  4    is a top-down cross-section illustration that shows the first example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  5    is a top-down cross-section illustration that shows a second example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  6    is a top-down cross-section illustration that shows the second example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  7    is a top-down cross-section illustration that shows a third example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  8    is a top-down cross-section illustration that shows the third example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  9    is a top-down cross-section illustration that shows a fourth example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  10    is a top-down cross-section illustration that shows the fourth example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  11    is a top-down cross-section illustration that shows a fifth example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  12    is a top-down cross-section illustration that shows the fifth example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  13    is a top-down cross-section illustration that shows a sixth example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  14    is a top-down cross-section illustration that shows the sixth example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  15    is a top-down cross-section illustration that shows a seventh example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  16    is a top-down cross-section illustration that shows the seventh example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  17    is a top-down cross-section illustration that shows an eighth example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  18    is a top-down cross-section illustration that shows the eighth example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  19    is a top-down cross-section illustration that shows a ninth example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  20    is a top-down cross-section illustration that shows the ninth example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  21    is a top-down cross-section illustration that shows a tenth example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  22    is a top-down cross-section illustration that shows the tenth example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  23    is a top-down cross-section illustration that shows an eleventh example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  24    is a top-down cross-section illustration that shows the eleventh example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  25    is a top-down cross-section illustration that shows an eleventh example of a head-mounted device with a first device portion and a second device portion of the head-mounted device shown in a disconnected position. 
         FIG.  26    is a top-down cross-section illustration that shows the eleventh example of the head-mounted device with the first device portion and the second device portion of the head-mounted device shown in a connected position. 
         FIG.  27    is a side view illustration that shows an adjustment assembly for IPD adjustment, vertical adjustment, and eye relief adjustment. 
         FIG.  28    is a side view illustration that shows an adjustment assembly for fine and gross adjustment. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure herein relates to head-mounted devices that are used to show computer-generated reality (CGR) content to users. The head-mounted devices that are described herein include adjustable components that allow features of the device to be adjusted to specific users. The adjustable components may include an interpupillary distance (IPD) adjustment mechanism that is operable to change the distance between the optical axes along which content is displayed to the left and right eyes of the user, such as by shifting the locations of optical modules that correspond to the user&#39;s left and right eyes or by shifting the locations of lenses that are included in the optical modules that correspond to the user&#39;s left and right eyes. The adjustable components may include an eye relief adjustment mechanism that is operable to change the distance between the optical modules and the user&#39;s eyes. Other adjustable components may be included. 
     In the implementations that are described herein, a head-mounted device includes a first device portion and a second device portion. The first device portion is shared by multiple users, and may include optical modules, sensors, processors, and/or other components. The second device portion is user-specific. In some implementations, the second device portion is connected to the first device portion, adjustable components of the first device portion are adjusted in dependence on settings that are controlled by features of the second device portion. The features of the second device portion may be, as examples, physical features, magnetic features, visible indicators, invisible indicators, information encoded in any format, and/or other features that are carried by the second device portion in a manner that can control adjustment of the adjustable components of the first device portion. 
       FIG.  1    is a block diagram that shows an example of a hardware configuration for a head-mounted device  100 . The head-mounted device  100  is intended to be worn on the head of a user and includes components that are configured to display content to the user. Components that are included in the head-mounted device  100  may be configured to track motion of parts of the user&#39;s body, such as the user&#39;s head and hands. Motion tracking information that is obtained by components of the head-mounted device can be utilized as inputs that control aspects of the generation and display of the content to the user, so that the content displayed to the user can be part of a CGR experience in which the user is able to view and interact with virtual environments and virtual objects. As will be explained further herein, CGR experiences include display of computer-generated content independent of the surrounding physical environment (e.g., virtual reality), and display of computer generated content that is overlaid relative to the surrounding physical environment (e.g., augmented reality). 
     In the illustrated example, the head-mounted device  100  includes a first device portion  102  and a second device portion  104 . The first device portion  102  is intended to be shared by multiple users. The second device portion  104  is not intended to be shared by multiple users, and instead, the second device portion  104  is intended to be user-specific. The first device portion  102  and the second device portion  104  include features that allow them to be securely connected to one another during use of the head-mounted device  100  by a specific user, and then disconnected from one another in preparation for use of the head-mounted device  100  by a different user. The second device portion  104  also includes features that cause adjustment of one or more adjustable components that are included in the first device portion  102 . 
     The first device portion  102  of the head-mounted device  100  may include a primary housing  106 , a support structure  108 , a first coupler portion  110 , a first adjuster portion  112 , a processor  114 , a memory  116 , a storage device  118 , a communications device  120 , sensors  122 , a power source  124 , a left optical module  126 , and a right optical module  128 . These components may be permanently connected portions of the first device portion  102  that are not intended to be disconnected from one another during the course of normal use of the head-mounted device  100 . 
     The primary housing  106  is a structure that supports various other components that are included in the first device portion  102  of the head-mounted device  100 . The primary housing  106  may have a size and shape that corresponds generally to the width of an average person&#39;s head. The primary housing  106  may have a height that corresponds generally to the distance between an average person&#39;s forehead and cheek bones such that it extends above and below the average person&#39;s orbital cavities. In one implementation, the primary housing  106  may be an enclosure that some or all of the components of the first device portion  102  are contained in. 
     The support structure  108  of the first device portion  102  is connected to the primary housing  106  of the first device portion  102 . The support structure  108  is a component or collection of components that function to secure the head-mounted device  100  in place with respect to the user&#39;s head so that the head-mounted device  100  is restrained from moving with respect to the user&#39;s head and maintains a comfortable position during use. The support structure  108  can be implemented using rigid structures, elastic flexible straps, or inelastic flexible straps. As one example, the support structure  108  may be a strap or may include multiple straps that are connected to the primary housing  106  of the first device portion  102  and which define a goggles-type support configuration that supports the head-mounted device  100  with respect to the head of the user. As another example, the support structure  108  may include a rigid structure that is connected to the primary housing  106  of the first device portion  102  to define a halo-type support configuration that supports the head-mounted device  100  with respect to the head of the user. 
     The first coupler portion  110  is a component or assembly that is included in the first device portion  102  of the head-mounted device  100 . The first coupler portion  110  allows connection of the first device portion  102  to the second device portion  104  of the head-mounted device  100 . 
     The first adjuster portion  112  is a component or assembly that is included in the first device portion  102  of the head-mounted device  100 . The first adjuster portion  112  allows adjustment of one or more components that are included in the first device portion  102  of the head-mounted device  100  in response to connection of the second device portion  104  to the first device portion  102 , as will be explained herein. The first adjuster portion  112  may include, for example, components that support the left optical module  126  and the right optical module  128  such that they are able to move. Examples of such components include rails, springs, linkages, elastic structures, magnets, and pneumatic elements. 
     The processor  114  is a device that is operable to execute computer program instructions and is operable to perform operations that are described by the computer program instructions. The processor  114  may be implemented using one or more conventional devices and/or more or more special-purpose devices. As examples, the processor  114  may be implemented using one or more central processing units, one or more graphics processing units, one or more application specific integrated circuits, and/or one or more field programmable gate arrays. The processor  114  may be provided with computer-executable instructions that cause the processor  114  to perform specific functions. The memory  116  may be one or more volatile, high-speed, short-term information storage devices such as random-access memory modules. 
     The storage device  118  is intended to allow for long term storage of computer program instructions and other data. Examples of suitable devices for use as the storage device  118  include non-volatile information storage devices of various types, such as a flash memory module, a hard drive, or a solid-state drive. 
     The communications device  120  supports wired or wireless communications with other devices. Any suitable wired or wireless communications protocol may be used. 
     The sensors  122  are components that are incorporated in first device portion  102  of the head-mounted device  100  to generate sensor output signals to are used as inputs by the processor  114  for use in generating CGR content, as will be described herein. The sensors  122  include components that facilitate motion tracking (e.g., head tracking and optionally handheld controller tracking in six degrees of freedom). The sensors  122  may also include additional sensors that are used by the device to generate and/or enhance the user&#39;s experience in any way. The sensors  122  may include conventional components such as cameras, infrared cameras, infrared emitters, depth cameras, structured-light sensing devices, accelerometers, gyroscopes, and magnetometers. The sensors  122  may also include biometric sensors that are operable to physical or physiological features of a person, for example, for use in user identification and authorization. Biometric sensors may include fingerprint scanners, retinal scanners, and face scanners (e.g., two-dimensional and three-dimensional scanning components operable to obtain image and/or three-dimensional surface representations). Other types of devices can be incorporated in the sensors  122 . The information that is generated by the sensors  122  is provided to other components of the head-mounted device  100 , such as the processor  114 , as inputs. 
     The sensors  122  may also include sensing components that are operable to determine the position of the left optical module  126  and the right optical module  128 . This allows content to be generated for the left optical module  126  and the right optical module  128  in dependence on their current positions after they are adjusted. As an example, the sensors  122  may include position encoders of any type that are configured to measure any or all of IPD, eye relief, and vertical position for the left optical module  126  and the right optical module  128 . Although shown as being incorporated in the first device portion  102 , the sensing components that are operable to determine the position of the left optical module  126  and the right optical module  128  could instead be included in the second device portion  104 . 
     The power source  124  is located in the primary housing  106  of the first device portion  102  of the head-mounted device  100  and supplies electrical power to components of the head-mounted device  100 . In some implementations, the power source  124  is a wired connection to electrical power. In some implementations, the power source  124  may include a battery of any suitable type, such as a rechargeable battery. In implementations that include a battery, the head-mounted device  100  may include components that facilitate wired or wireless recharging. 
     The left optical module  126  and the right optical module  128  are assemblies that function to show images to the user. The left optical module  126  and the right optical module  128  are included in the first device portion  102  and are connected to and supported by the primary housing  106  of the first device portion  102 . The left optical module  126  displays a first image that is intended to be seen by the user&#39;s left eye and which may be referred to herein as a left-eye image. The right optical module  128  displays a first image that is intended to be seen by the user&#39;s right eye and which may be referred to herein as a right-eye image. By allowing display of the left-eye image and the right-eye image as separate images, the left optical module  126  and the right optical module  128  facilitate display of stereoscopic images to the user, such that the user may perceive the displayed images as a three-dimensional representation of a CGR environment. 
     The second device portion  104  may include a secondary housing  130 , a face cushion  132 , a second coupler portion  134 , a second adjuster portion  136 , and vision correction lenses  138 . 
     The secondary housing  130  is a structure that supports various other components that are included in the second device portion  104  of the head-mounted device  100 . The secondary housing  130  may have a size and shape that corresponds generally to the width of an average person&#39;s head. The secondary housing  130  may have a height that corresponds generally to the distance between an average person&#39;s forehead and cheek bones such that it extends above and below the average person&#39;s orbital cavities. In one implementation, the secondary housing  130  may be a frame or enclosure that some or all of the components of the second device portion  104  are connected to or contained in. 
     The face cushion  132  is connected to the secondary housing  130  and is located at areas around a periphery of the secondary housing  130  where contact with the user&#39;s face is likely. The face cushion  132  functions to conform to portions of the user&#39;s face to allow the support structure  108  of the first device portion  102  to be tensioned to an extent that will restrain motion of the head-mounted device  100  with respect to the user&#39;s head. The face cushion  132  may also function to reduce the amount of light from the physical environment around the user that reaches the user&#39;s eyes. The face cushion  132  may contact areas of the user&#39;s face, such as the user&#39;s forehead, temples, and cheeks. The face cushion  132  may be formed from a compressible material, such as open-cell foam or closed cell foam, so that the head-mounted device  100  may be held securely with respect to the user&#39;s head without discomfort. 
     The second coupler portion  134  is a component or assembly that is included in the second device portion  104  of the head-mounted device  100 . The second coupler portion  134  allows connection of the first device portion  102  to the second device portion  104  of the head-mounted device  100 . The second coupler portion  134  is connectable to the first coupler portion  110  of the first device portion  102  to connect the first device portion  102  to the second device portion  104 . 
     The first coupler portion  110  and the second coupler portion  134  allow the first device portion  102  and the second device portion  104  to be moved between a disconnected position and a connected position. In the disconnected position, the first coupler portion  110  and the second coupler portion  134  are not engaged with each other and the first device portion  102  is not connected to (i.e., disconnected from) the second device portion  104 . In the connected position, the first coupler portion  110  and the second coupler portion  134  are engaged with each other and the first device portion  102  is connected to the second device portion  104 . 
     As one example, the first coupler portion  110  and the second coupler portion  134  may be physical connection structures such as surfaces that define a friction fit or complementary mechanical elements, such as hooks, catches, latches, snaps, etc. As another example, the first coupler portion  110  and the second coupler portion  134  may include magnetic connection structures (e.g., a group of magnets connectable to a group of ferromagnetic elements). The first coupler portion  110  or the second coupler portion  134  may, in some implementations, include a release mechanism, such as a button that causes disengagement of the first coupler portion  110  and the second coupler portion  134  when depressed. 
     In some implementations, the first coupler portion  110  and the second coupler portion  134  may be configured to separate in response to application of force above a threshold to the head-mounted device (e.g., by separation of a friction fit or magnetic connection). Application of force above a threshold may occur, for example, if the head-mounted device  100  is dropped. By separation of the first coupler portion  110  and the second coupler portion  134 , the second device portion  104  is released from the first device portion  102 . As will be explained further herein, position adjustment for the left optical module  126  and the right optical module  128  is set by connection of the second device portion  104  to the first device portion  102 . When the second device portion  104  is released the first device portion  102 , the left optical module  126  and the right optical module  128  may move relative to the primary housing  106  of the first device portion  102  as opposed to being fixed in place. Motion of the left optical module  126  and the right optical module  128  cushions them against damage (e.g., during a fall) by allowing the adjustment components (e.g., springs) to absorb energy. 
     The second adjuster portion  136  is a component or assembly that is included in the second device portion  104  of the head-mounted device  100 . The second adjuster portion  136  is operable to cause adjustment of one or more components that are included in the first device portion  102  of the head-mounted device  100  in response to connection of the second device portion  104  to the first device portion  102 , as will be explained herein. As an example, the first adjuster portion  112  of the first device portion  102  may include a moveable component, and connection of the second device portion  104  to the first device portion  102  may engage the second adjuster portion  136  of the second device portion  104  with the first adjuster portion  112  of the first device portion  102  to cause movement of the first adjuster portion  112 . In another example, the optical module locations may be readily adjusted by virtue of malleability of certain features of the second device portion  104 , and the structure is fixed in place once adjustments are complete. As examples, low temperature plastics or magnetorheological fluid can be used. Additional examples of the structure and operation of the first adjuster portion  112  and the second adjuster portion  136  will be described in detail herein. 
     The vision correction lenses  138  are user-specific lenses intended to correct the user&#39;s vision (e.g., prescription lenses). The vision correction lenses  138  may be permanently connected to the secondary housing  130  of the second device portion  104  or may be removably connected (connectable and disconnectable) to the secondary housing  130  of the second device portion  104 . 
     In some implementations, the vision correction lenses  138  may define a field of view that is user-specific. The field of view may be a predetermined user-selected field of view if the vision correction lenses  138  are permanently connected to the secondary housing  130 . The field of view may be changeable by replacing lenses if the vision correction lenses  138  are removably connected to the secondary housing  130 . 
     In some implementations, the vision correction lenses  138  may define a binocular overlap that is user-specific. The binocular overlap may be a predetermined user-selected binocular overlap if the vision correction lenses  138  are permanently connected to the secondary housing  130 . The binocular overlap may be changeable by replacing lenses if the vision correction lenses  138  are removably connected to the secondary housing  130 . 
     In the description above, the support structure  108  is part of the first device portion  102  and is connected to the primary housing  106 . It should be understood that the support structure  108  can instead be part of the second device portion  104  and be connected to the secondary housing  130  of the second device portion  104 . For example, the support structure  108  may have a goggles-type strap configuration that is connected to the secondary housing  130  of the second device portion  104  or the support structure may have a halo-type configuration having one or more rigid structures that are connected to the secondary housing  130  of the second device portion  104 . 
     The two-part architecture of the head-mounted device  100  allows for customization of other aspects of the second device portion  104  in addition to setting optical module positions upon connection of the second device portion  104  to the first device portion  102 . As one example, the face cushion  132  may be customized for the user. In one implementation, the face cushion  132  may be head-molded to the contours of the user&#39;s face. In another implementation, loss of calibration between the lens and display of either of the left optical module  126  and the right optical module  128  may be corrected by changes to the second device portion  104 , which may be performed using a calibration fixture. 
       FIG.  2    is an illustration that shows an example implementation of the left optical module  126  of the first device portion  102  of the head-mounted device  100 . The configuration shown and described for the left optical module  126  can also be used to implement the right optical module  128 . In the illustrated example, the left optical module  126  includes an optical module housing  240 , a display device  242 , and an optical system  244 . 
     The display device  242  is connected to the optical module housing  240  and functions to display content to the user. The display device  242  is a light-emitting display device, such as a video display of any suitable type, that is able to output images in response to a signal that is received from the processor  114 . The display device  242  may be of the type that selectively illuminates individual display elements according to a color and intensity in accordance with pixel values from an image. As examples, the display device may be implemented using a liquid-crystal display (LCD) device, a light-emitting diode (LED) display device, a liquid crystal on silicon (LCoS) display device, an organic light-emitting diode (OLED) display device, or any other suitable type of display device. The display device  242  may include multiple individual display devices (e.g., two display screens or other display devices arranged side-by-side in correspondence to the user&#39;s left eye and the user&#39;s right eye). 
     The optical system  244  is connected to the optical module housing  240  is associated with the display device  242  such that light emitted by the display device  242  is incident upon components (e.g., lenses) of the optical system  244 . Thus, the optical system  244  is optically coupled to the display device  242  such that is directs light from the display device toward the user&#39;s eye. The optical system  244  is connected to the optical module housing  240  such that portions of the optical system  244  (e.g., lenses) are positioned adjacent to the user&#39;s eye. The optical system  244  directs the emitted light from the display device  242  to the user&#39;s eyes. In the illustrated example, the optical system  244  is configured isolate the emitted light from environmental light (e.g., as in a virtual reality type system). In alternative implementations, the optical system  244  may be configured to combine the emitted light with environmental light such that a spatial correspondence is established between the emitted light and the environmental light (e.g., as in an augmented reality type system). The optical system  244  may include one or more lenses, reflectors, polarizers, filters, optical combiners, and/or other optical components. 
       FIG.  3    is a top-down cross-section illustration that shows a first example of a head-mounted device  300  with a first device portion  302  and a second device portion of the head-mounted device  300  shown in a disconnected position.  FIG.  4    is a top-down cross-section illustration that shows the first example of the head-mounted device  300  with the first device portion  302  and the second device portion  304  of the head-mounted device  300  shown in a connected position. 
     The head-mounted device  300  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  300 . 
     The first device portion  302  of the head-mounted device  300  includes a primary housing  306 , a first coupler portion  310 , a first adjuster portion  312 , a left optical module  326 , and a right optical module  328 . The second device portion  304  of the head-mounted device  300  includes a secondary housing  330 , a face cushion  332 , a second coupler portion  334 , and a second adjuster portion  336 . An opening  331  is formed in the secondary housing  330  to allow visibility of the left optical module  326  and the right optical module  328  when the head-mounted device  300  is worn by a user. Other components may be included in the first device portion  302  and the second device portion  304  of the head-mounted device  300 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  312  and the second adjuster portion  336  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  326  and an optical axis of the right optical module  328  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  312  is an assembly that includes a rail  351  and springs  352 . The rail  351  may be located in the primary housing  306  and fixed with respect to the primary housing  306 . The left optical module  326  and the right optical module  328  are connected to the rail  351  and supported with respect to the rail  351  to allow lateral (side-to-side) sliding of the left optical module  326  and the right optical module  328  with respect to the rail  351  and with respect to the primary housing  306 . The rail  351  may be any structural element that allows the left optical module  326  and the right optical module  328  to be mounted to it in a manner that allows sliding. The rail  351  may be a single structure or may include multiple structures. Sliding motion of the left optical module  326  and the right optical module  328  with respect to the rail includes sliding of the left optical module  326  and the right optical module  328  toward one another to decrease the IPD and sliding of the left optical module  326  and the right optical module  328  away from one another to increase the IPD. 
     The springs  352  define an initial position for the left optical module  326  and the right optical module  328  in the disconnected position. The springs  352  resist movement of the left optical module  326  and the right optical module  328  in a laterally outward direction with respect to the rail  351  and urge the left optical module  326  and the right optical module  328  toward each other in a laterally inward direction. In the illustrated implementation, the springs  352  are compression springs that are located laterally outward from the left optical module  326  and the right optical module  328 . In an alternative implementation, the springs  352  may be replaced by one or more springs that have a different configuration and are likewise configured to resist movement of the left optical module  326  and the right optical module  328  in a laterally outward direction with respect to the rail  351  and urge the left optical module  326  and the right optical module  328  toward each other in a laterally inward direction. For example, the springs  352  could be replaced by one or more tension springs that are located between the left optical module  326  and the right optical module  328  and which are configured to urge the left optical module  326  and the right optical module  328  laterally inward. 
     The first adjuster portion  312  also includes a first contact surface  353  and a second contact surface  354 . The first contact surface  353  is formed on or connected to the left optical module  326  at laterally inward location relative to the left optical module  326 . The second contact surface  354  is formed on or connected to the right optical module  328  at laterally inward location relative to the right optical module  328 . Thus, the first contact surface  353  and the second contact surface  354  are located laterally between the left optical module  326  and the right optical module  328 . In the illustrated example, the first contact surface  353  and the second contact surface  354  are inclined such that force applied in a longitudinal (front-to-back) direction causes the left optical module  326  and the right optical module  328  to move laterally outward with respect to each other. 
     The second adjuster portion  336  also includes a wedge structure that is defined by a first contact surface  355  and a second contact surface  356 . The first contact surface  355  and the second contact surface  356  are formed on or connected to the secondary housing  330  of the second device portion  304 . As an example, the first contact surface  355  and the second contact surface  356  may define a wedge that serves as a structural rib that also supports the face cushion  332 . 
     In the illustrated example, the first contact surface  355  and the second contact surface  356  of the second device portion  304  are inclined in a wedge shaped configuration such that they are configured to engage the first contact surface  353  and the second contact surface  354  of the first device portion  302  during connection of the second device portion  304  to the first device portion  302  to move the left optical module  326  and the right optical module  328  laterally away from each other. Thus, in the disconnected position, the left optical module  326  and the right optical module  328  are positioned laterally inward relative to the primary housing  306  (e.g., toward a lateral center of the primary housing  306 ), and in the connected position that the left optical module  326  and the right optical module  328  have been moved laterally away from each other as a result of engagement of the first contact surface  355  and the second contact surface  356  of the second adjuster portion  336  with the first contact surface  353  and the second contact surface  354  of the first adjuster portion  312 . 
     The second device portion  304  is connectable to and disconnectable from the first device portion  302  by engagement and disengagement of the first coupler portion  310  of the first device portion  302  with the second coupler portion  334  of the second device portion  304 . Connection and disconnection of the first coupler portion  310  and the second coupler portion  334  allows movement of the first device portion  302  and the second device portion  304  between the disconnected position ( FIG.  3   ) and the connected position ( FIG.  4   ). As previously described, the first coupler portion  310  and the second coupler portion  334  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  336  of the second device portion  304  is configured to cause the left optical module  326  and the right optical module  328  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  304  to the first device portion  302 . Several similarly configured second device portions may be made for use with the first device portion  302 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  302  with their own user-specific instance of the second device portion  304 . 
       FIG.  5    is an illustration that shows a second example of a head-mounted device  500  with a first device portion  502  and a second device portion of the head-mounted device  500  shown in a disconnected position.  FIG.  6    is an illustration that shows the second example of the head-mounted device  500  with the first device portion  502  and the second device portion  504  of the head-mounted device  500  shown in a connected position. 
     The head-mounted device  500  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  500 . 
     The first device portion  502  of the head-mounted device  500  includes a primary housing  506 , a first coupler portion  510 , a first adjuster portion  512 , a left optical module  526 , and a right optical module  528 . The second device portion  504  of the head-mounted device  500  includes a secondary housing  530 , a face cushion  532 , a second coupler portion  534 , and a second adjuster portion  536 . An opening  531  is formed in the secondary housing  530  to allow visibility of the left optical module  526  and the right optical module  528  when the head-mounted device  500  is worn by a user. Other components may be included in the first device portion  502  and the second device portion  504  of the head-mounted device  500 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  512  and the second adjuster portion  536  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  526  and an optical axis of the right optical module  528  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  512  is an assembly that includes a rail  551  and a spring  552 . The rail  551  may be located in the primary housing  506  and fixed with respect to the primary housing  506 . The left optical module  526  and the right optical module  528  are connected to the rail  551  and supported with respect to the rail  551  to allow lateral (side-to-side) sliding of the left optical module  526  and the right optical module  528  with respect to the rail  551  and with respect to the primary housing  506 . The rail  551  may be any structural element that allows the left optical module  526  and the right optical module  528  to be mounted to it in a manner that allows sliding. The rail  551  may be a single structure or may include multiple structures. Sliding motion of the left optical module  526  and the right optical module  528  with respect to the rail includes sliding of the left optical module  526  and the right optical module  528  toward one another to decrease the IPD and sliding of the left optical module  526  and the right optical module  528  away from one another to increase the IPD. 
     The spring  552  define an initial position for the left optical module  526  and the right optical module  528  in the disconnected position. The spring  552  resists movement of the left optical module  526  and the right optical module  528  in a laterally inward direction with respect to the rail  551  and urges the left optical module  526  and the right optical module  528  away from each other in a laterally outward direction. In the illustrated implementation, the spring  552  is a compression spring that is located laterally inward relative to and between the left optical module  526  and the right optical module  528 . In an alternative implementation, the spring  552  may be replaced by one or more springs that have a different configuration and are likewise configured to resist movement of the left optical module  526  and the right optical module  528  in a laterally inward direction with respect to the rail  551  and urge the left optical module  526  and the right optical module  528  away from each other in a laterally outward direction. For example, the spring  552  could be replaced by tension springs that are each located laterally outward from one of the left optical module  526  or the right optical module  528  and which are configured to urge the left optical module  526  and the right optical module  528  laterally outward toward side walls of the primary housing  506 . 
     The first adjuster portion  512  also includes a first contact surface  553  and a second contact surface  554 . The first contact surface  553  is formed on or connected to the left optical module  526  at laterally outward location relative to the left optical module  526 . The second contact surface  554  is formed on or connected to the right optical module  528  at a laterally outward location relative to the right optical module. In the illustrated example, the first contact surface  553  and the second contact surface  554  are inclined such that force applied in a longitudinal (front-to-back) direction causes the left optical module  526  and the right optical module  528  to move laterally inward with respect to each other. 
     The second adjuster portion  536  also includes two wedge structures that are defined by a first contact surface  555  and a second contact surface  556 . The first contact surface  555  is formed on or connected to the secondary housing  530  near a left lateral side of the secondary housing  530 . The second contact surface  556  is formed on or connected to the secondary housing  530  near a right lateral side of the secondary housing  530 . In the illustrated example, the first contact surface  555  and the second contact surface  556  of the second device portion  504  are inclined inward toward each other such that they are configured to engage the first contact surface  553  and the second contact surface  554  of the first device portion  502  during connection of the second device portion  504  to the first device portion  502  to move the left optical module  526  and the right optical module  528  laterally toward from each other. Thus, in the disconnected position, the left optical module  526  and the right optical module  528  are positioned laterally outward relative to the primary housing  506  (e.g., away from a lateral center of the primary housing  506  and near the lateral side walls of the primary housing  506 ), and in the connected position that the left optical module  526  and the right optical module  528  have been moved laterally toward each other as a result of engagement of the first contact surface  555  and the second contact surface  556  of the second adjuster portion  536  with the first contact surface  553  and the second contact surface  554  of the first adjuster portion  512 . 
     The second device portion  504  is connectable to and disconnectable from the first device portion  502  by engagement and disengagement of the first coupler portion  510  of the first device portion  502  with the second coupler portion  534  of the second device portion  504 . Connection and disconnection of the first coupler portion  510  and the second coupler portion  534  allows movement of the first device portion  502  and the second device portion  504  between the disconnected position ( FIG.  5   ) and the connected position ( FIG.  6   ). As previously described, the first coupler portion  510  and the second coupler portion  534  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  536  of the second device portion  504  is configured to cause the left optical module  526  and the right optical module  528  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  504  to the first device portion  502 . Several similarly configured second device portions may be made for use with the first device portion  502 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  502  with their own user-specific instance of the second device portion  504 . 
       FIG.  7    is an illustration that shows a third example of a head-mounted device  700  with a first device portion  702  and a second device portion of the head-mounted device  700  shown in a disconnected position.  FIG.  8    is an illustration that shows the third example of the head-mounted device  700  with the first device portion  702  and the second device portion  704  of the head-mounted device  700  shown in a connected position. 
     The head-mounted device  700  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  700 . 
     The first device portion  702  of the head-mounted device  700  includes a primary housing  706 , a first coupler portion  710 , a first adjuster portion  712 , a left optical module  726 , and a right optical module  728 . The second device portion  704  of the head-mounted device  700  includes a secondary housing  730 , a face cushion  732 , a second coupler portion  734 , and a second adjuster portion  736 . Openings  731  are formed in the secondary housing  730  to allow visibility of the left optical module  726  and the right optical module  728  when the head-mounted device  700  is worn by a user. Other components may be included in the first device portion  702  and the second device portion  704  of the head-mounted device  700 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  712  and the second adjuster portion  736  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  726  and an optical axis of the right optical module  728  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  712  is an assembly that includes a rail  751  and springs  752 . The rail  751  may be located in the primary housing  706  and fixed with respect to the primary housing  706 . The left optical module  726  and the right optical module  728  are connected to the rail  751  and supported with respect to the rail  751  to allow lateral (side-to-side) sliding of the left optical module  726  and the right optical module  728  with respect to the rail  751  and with respect to the primary housing  706 . The rail  751  may be any structural element that allows the left optical module  726  and the right optical module  728  to be mounted to it in a manner that allows sliding. The rail  751  may be a single structure or may include multiple structures. Sliding motion of the left optical module  726  and the right optical module  728  with respect to the rail includes sliding of the left optical module  726  and the right optical module  728  toward one another to decrease the IPD and sliding of the left optical module  726  and the right optical module  728  away from one another to increase the IPD. 
     The springs  752  define an initial position for the left optical module  726  and the right optical module  728  in the disconnected position. The springs  752  resist lateral movement of the left optical module  726  and the right optical module  728  relative to a neutral position. As an example, the neutral position may be a position in which the IPD is between a minimum IPD value and a maximum IPD value. In the illustrated implementation, the springs  752  include a compression spring that is located laterally between the left optical module  726  and the right optical module  728  as well as compression springs that are located laterally outward from the left optical module  726  and the right optical module  728 . In an alternative implementation, the spring  752  may be replaced by one or more springs that have a different configuration and are likewise configured to resist lateral movement of the left optical module  726  and the right optical module  728  away from a neutral position. 
     The first adjuster portion  712  also includes a first contact surface  753  and a second contact surface  754 . The first contact surface  753  is an annular surface (e.g., a first annular contact surface) formed on or connected to the left optical module  726  such that it extends around the left optical module  726  and defines an outward facing surface that is inclined relative to the longitudinal direction (e.g., front-rear direction that generally corresponds to the optical axes of the optical modules). The second contact surface  754  is an annular surface (e.g., a second annular contact surface) formed on or connected to the right optical module  728  such that it extends around the right optical module  728  and defines an outward facing surface that is inclined relative to the longitudinal direction (e.g., front-rear direction that generally corresponds to the optical axes of the optical modules). 
     The second adjuster portion  736  also includes a first contact surface  755  and a second contact surface  756 . The first contact surface  755  is formed on or connected to the secondary housing  730  and is an annular structure that includes an inward facing inclined surface that generally corresponds to and is complementary to the position and geometry of the first contact surface  753  of the first adjuster portion  712  of the first device portion  702 . The second contact surface  756  is formed on or connected to the secondary housing  730  and is an annular structure that includes an inward facing inclined surface that generally corresponds to and is complementary to the position and geometry of the second contact surface  754  of the first adjuster portion  712  of the first device portion  702 . 
     The first contact surface  755  and the second contact surface  756  of the second device portion  704  are configured to engage the first contact surface  753  and the second contact surface  754  of the first device portion  702  during connection of the second device portion  704  to the first device portion  702  to move the left optical module  726  and the right optical module  728  laterally in dependence on an offset between the first contact surface  755  and the second contact surface  756  of the second device portion  704  with respect to the first contact surface  753  and the second contact surface  754  of the first device portion  702 . Thus, connecting the second device portion  704  to the first device portion  702  causes engagement of the first contact surface  755  of the second device portion  704  with the first contact surface  753  of the left optical module  726 , which shifts the position of the left optical module  726  into alignment with the first contact surface  755  of the second device portion  704 . Connecting the second device portion  704  to the first device portion  702  also causes engagement of the second contact surface  756  of the second device portion  704  with the second contact surface  754  of the right optical module  728 , which shifts the position of the right optical module  728  into alignment with the second contact surface  756  of the second device portion  704 . Due to the annular nature of the contact surfaces, this configuration may also be used to drive vertical adjustment of the left optical module  726  and the right optical module  728  in implementations that include a vertical position adjustment stage for the left optical module  726  and the right optical module  728 , as will be explained further herein. 
     The second device portion  704  is connectable to and disconnectable from the first device portion  702  by engagement and disengagement of the first coupler portion  710  of the first device portion  702  with the second coupler portion  734  of the second device portion  704 . Connection and disconnection of the first coupler portion  710  and the second coupler portion  734  allows movement of the first device portion  702  and the second device portion  704  between the disconnected position ( FIG.  7   ) and the connected position ( FIG.  8   ). As previously described, the first coupler portion  710  and the second coupler portion  734  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  736  of the second device portion  704  is configured to cause the left optical module  726  and the right optical module  728  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  704  to the first device portion  702 . Several similarly configured second device portions may be made for use with the first device portion  702 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  702  with their own user-specific instance of the second device portion  704 . 
       FIG.  9    is a top-down cross-section illustration that shows a fourth example of a head-mounted device  900  with a first device portion  902  and a second device portion of the head-mounted device  900  shown in a disconnected position.  FIG.  10    is a top-down cross-section illustration that shows the fourth example of the head-mounted device  900  with the first device portion  902  and the second device portion  904  of the head-mounted device  900  shown in a connected position. 
     The head-mounted device  900  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  900 . 
     The first device portion  902  of the head-mounted device  900  includes a primary housing  906 , a first coupler portion  910 , a first adjuster portion  912 , a left optical module  926 , and a right optical module  928 . The second device portion  904  of the head-mounted device  900  includes a secondary housing  930 , a face cushion  932 , a second coupler portion  934 , and a second adjuster portion  936 . An opening  931  is formed in the secondary housing  930  to allow visibility of the left optical module  926  and the right optical module  928  when the head-mounted device  900  is worn by a user. Other components may be included in the first device portion  902  and the second device portion  904  of the head-mounted device  900 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  912  and the second adjuster portion  936  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  926  and an optical axis of the right optical module  928  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  912  is an assembly that includes a rail  951  and springs  952 . The rail  951  may be located in the primary housing  906  and fixed with respect to the primary housing  906 . The left optical module  926  and the right optical module  928  are connected to the rail  951  and supported with respect to the rail  951  to allow lateral (side-to-side) sliding of the left optical module  926  and the right optical module  928  with respect to the rail  951  and with respect to the primary housing  906  (e.g., the left optical module  926  and the right optical module  928  are slidably mounted to the rail  951 ). The rail  951  may be any structural element that allows the left optical module  926  and the right optical module  928  to be mounted to it in a manner that allows sliding. The rail  951  may be a single structure or may include multiple structures. Sliding motion of the left optical module  926  and the right optical module  928  with respect to the rail includes sliding of the left optical module  926  and the right optical module  928  toward one another to decrease the IPD and sliding of the left optical module  926  and the right optical module  928  away from one another to increase the IPD. 
     The springs  952  define an initial position for the left optical module  926  and the right optical module  928  in the disconnected position. The springs  952  resist movement of the left optical module  926  and the right optical module  928  in a laterally outward direction with respect to the rail  951  and urge the left optical module  926  and the right optical module  928  toward each other in a laterally inward direction. In the illustrated implementation, the springs  952  are compression springs that are located laterally outward from the left optical module  926  and the right optical module  928 . In an alternative implementation, the springs  952  may be replaced by one or more springs that have a different configuration and are likewise configured to resist movement of the left optical module  926  and the right optical module  928  in a laterally outward direction with respect to the rail  951  and urge the left optical module  926  and the right optical module  928  toward each other in a laterally inward direction. For example, the springs  952  could be replaced by one or more tension springs that are located between the left optical module  926  and the right optical module  928  and which are configured to urge the left optical module  926  and the right optical module  928  laterally inward. 
     The first adjuster portion  912  also includes a first cam  953  and a second cam  954 . The first cam  953  is located in the primary housing  906  adjacent to the left optical module  926  and is positioned at a laterally inward location relative to the left optical module  926 . The second cam  954  is located in the primary housing  906  adjacent to the right optical module  928  and is positioned at a laterally inward location relative to the right optical module  928 . A similar configuration could be implemented with the first cam  953  and the second cam  954  positioned laterally outward from the left optical module  926  and the right optical module  928 . The first cam  953  and the second cam  954  are each arranged around a rotation axis (e.g., an axle) and the distance between the rotation axis and the outer periphery of each of the first cam  953  and the second cam  954  varies between a minimum distance and a maximum distance. 
     The second adjuster portion  936  also includes a first engaging structure  955  and a second engaging structure  956 . The first engaging structure  955  and the second engaging structure  956  are formed on or connected to the secondary housing  930  of the second device portion  904 . In the illustrated example, the first engaging structure  955  and the second engaging structure  956  are protruding members that are configured to engage the first cam  953  and the second cam  954  and thereby cause rotation of the first cam  953  and the second cam  954  as the second device portion  904  is moved into the connected position with respect to the first device portion  902 . To cause rotation of the first cam  953  and the second cam  954 , any suitable configuration can be used for the first engaging structure  955  and the second engaging structure  956 , such as a high-friction engaging surface or a gear track. When the first cam  953  and the second cam  954  rotate, they engage the left optical module  926  and the right optical module  928 , which changes the distance between the rotation axes of each of the first cam  953  and the second cam  954  with respect to the left optical module  926  and the right optical module  928  in accordance with the geometric configuration of the outer periphery of the first cam  953  and the second cam  954 . 
     The first cam  953  and the second cam  954  are examples of mechanical amplifiers in that they are operable to shift the position of the left optical module  926  and the right optical module  928  by a distance that is greater than the length of the effective mechanical stroke of the first engaging structure  955  and the second engaging structure  956  as they enter the primary housing  906  of the first device portion  902  and engage the first cam  953  and the second cam  954 . Other types of mechanical amplifiers can be used in a similar configuration in place of the first cam  953  and the second cam  954 . Examples of mechanical amplifiers include levers, cam tracks, four bar linkages, etc. 
     The second device portion  904  is connectable to and disconnectable from the first device portion  902  by engagement and disengagement of the first coupler portion  910  of the first device portion  902  with the second coupler portion  934  of the second device portion  904 . Connection and disconnection of the first coupler portion  910  and the second coupler portion  934  allows movement of the first device portion  902  and the second device portion  904  between the disconnected position ( FIG.  9   ) and the connected position ( FIG.  10   ). As previously described, the first coupler portion  910  and the second coupler portion  934  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  936  of the second device portion  904  is configured to cause the left optical module  926  and the right optical module  928  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  904  to the first device portion  902 . Several similarly configured second device portions may be made for use with the first device portion  902 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  902  with their own user-specific instance of the second device portion  904 . 
       FIG.  11    is an illustration that shows a fifth example of a head-mounted device  1100  with a first device portion  1102  and a second device portion of the head-mounted device  1100  shown in a disconnected position.  FIG.  12    is an illustration that shows the fifth example of the head-mounted device  1100  with the first device portion  1102  and the second device portion  1104  of the head-mounted device  1100  shown in a connected position. 
     The head-mounted device  1100  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  1100 . 
     The first device portion  1102  of the head-mounted device  1100  includes a primary housing  1106 , a first coupler portion  1110 , a first adjuster portion  1112 , a left optical module  1126 , and a right optical module  1128 . The second device portion  1104  of the head-mounted device  1100  includes a secondary housing  1130 , a face cushion  1132 , a second coupler portion  1134 , and a second adjuster portion  1136 . An opening  1131  is formed in the secondary housing  1130  to allow visibility of the left optical module  1126  and the right optical module  1128  when the head-mounted device  1100  is worn by a user. Other components may be included in the first device portion  1102  and the second device portion  1104  of the head-mounted device  1100 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  1112  and the second adjuster portion  1136  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  1126  and an optical axis of the right optical module  1128  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  1112  is an assembly that includes a rail  1151 , springs  1152 , a first releasable locking structure  1153 , and a second releasable locking structure  1154 . The rail  1151  may be located in the primary housing  1106  and fixed with respect to the primary housing  1106 . The left optical module  1126  and the right optical module  1128  are connected to the rail  1151  and supported with respect to the rail  1151  to allow lateral (side-to-side) sliding of the left optical module  1126  and the right optical module  1128  with respect to the rail  1151  and with respect to the primary housing  1106 . The rail  1151  may be any structural element that allows the left optical module  1126  and the right optical module  1128  to be mounted to it in a manner that allows sliding. The rail  1151  may be a single structure or may include multiple structures. Sliding motion of the left optical module  1126  and the right optical module  1128  with respect to the rail includes sliding of the left optical module  1126  and the right optical module  1128  toward one another to decrease the IPD and sliding of the left optical module  1126  and the right optical module  1128  away from one another to increase the IPD. 
     The springs  1152  define an initial position for the left optical module  1126  and the right optical module  1128  in the disconnected position. The springs  1152  resists movement of the left optical module  1126  and the right optical module  1128  in a laterally outward direction with respect to the rail  1151  and urges the left optical module  1126  and the right optical module  1128  toward from each other in a laterally inward direction. In the illustrated implementation, the springs  1152  is a compression springs that are located laterally outward relative to the left optical module  1126  and the right optical module  1128 . In an alternative implementation, the spring  1152  may be replaced by one or more springs that have a different configuration and are likewise configured to resist movement of the left optical module  1126  and the right optical module  1128  in a laterally outward direction with respect to the rail  1151  and urge the left optical module  1126  and the right optical module  1128  toward from each other in a laterally inward direction. For example, the springs  1152  could be replaced by a tension spring that is located between the left optical module  1126  and the right optical module  1128  and which are configured to urge the left optical module  1126  and the right optical module  1128  laterally inward toward a lateral center of the primary housing  1106 . 
     The first adjuster portion  1112  also includes the first releasable locking structure  1153  and the second releasable locking structure  1154 . The first releasable locking structure  1153  and the second releasable locking structure  1154  engageable with the left optical module and the right optical module  1128  to hold them at a laterally outward position near the lateral side walls of the primary housing  306  and against the force applied by the springs  1152  (e.g., the springs  1152  are held in a compressed position). The first releasable locking structure  1153  and the second releasable locking structure  1154  are any type of device that is configured to hold the left optical module  1126  and the right optical module  1128  in the laterally outward position when the first device portion  1102  and the second device portion  1104  are in the disconnected position. As examples, the first releasable locking structure  1153  and the second releasable locking structure  1154  may be or include latches, hooks, magnetic elements, etc. The first releasable locking structure  1153  and the second releasable locking structure  1154  are configured to be released, such as by user operation of a switch or by engagement of a part of the second device portion  304  during movement from the disconnected position to the connected position. 
     The second adjuster portion  1136  also includes a first stop surface  1155  and a second stop surface  1156  that control movement of the left optical module  1126  and the right optical module  1128  to allow the left optical module  1126  and the right optical module  1128  to move to an adjusted position. The first stop surface  1155  and the second stop surface  1156  are positioned (fixed or adjustably) on the secondary housing  1130  at locations that correspond to a desired IPD between the left optical module  1126  and the right optical module  1128 . Upon connection of the second device portion  1104  to the first device portion  1102 , the first releasable locking structure  1153  and the second releasable locking structure  1154  are operated to release the left optical module  1126  and the right optical module  1128 , causing them to move laterally inward under the forces applied by the springs  1152  until the left optical module  1126  reaches and engages the first stop surface  1155  and the right optical module  1128  reaches and engages the second stop surface  1156 . Engagement with the first stop surface  1155  and the second stop surface  1156  ceases inward movement of the left optical module  1126  and the right optical module  1128 , thereby setting the IPD according to the locations of the first stop surface  1155  and the second stop surface  1156 . 
     The second device portion  1104  is connectable to and disconnectable from the first device portion  1102  by engagement and disengagement of the first coupler portion  1110  of the first device portion  1102  with the second coupler portion  1134  of the second device portion  1104 . Connection and disconnection of the first coupler portion  1110  and the second coupler portion  1134  allows movement of the first device portion  1102  and the second device portion  1104  between the disconnected position ( FIG.  11   ) and the connected position ( FIG.  12   ). As previously described, the first coupler portion  1110  and the second coupler portion  1134  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  1136  of the second device portion  1104  is configured to cause the left optical module  1126  and the right optical module  1128  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  1104  to the first device portion  1102 . Several similarly configured second device portions may be made for use with the first device portion  1102 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  1102  with their own user-specific instance of the second device portion  1104 . 
       FIG.  13    is an illustration that shows a sixth example of a head-mounted device  1300  with a first device portion  1302  and a second device portion of the head-mounted device  1300  shown in a disconnected position.  FIG.  14    is an illustration that shows the sixth example of the head-mounted device  1300  with the first device portion  1302  and the second device portion  1304  of the head-mounted device  1300  shown in a connected position. 
     The head-mounted device  1300  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  1300 . 
     The first device portion  1302  of the head-mounted device  1300  includes a primary housing  1306 , a first coupler portion  1310 , a first adjuster portion  1312 , a left optical module  1326 , and a right optical module  1328 . The second device portion  1304  of the head-mounted device  1300  includes a secondary housing  1330 , a face cushion  1332 , a second coupler portion  1334 , and a second adjuster portion  1336 . Openings  1331  are formed in the secondary housing  1330  to allow visibility of the left optical module  1326  and the right optical module  1328  when the head-mounted device  1300  is worn by a user. Other components may be included in the first device portion  1302  and the second device portion  1304  of the head-mounted device  1300 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  1312  and the second adjuster portion  1336  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  1326  and an optical axis of the right optical module  1328  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  1312  is an assembly that includes a rail  1351  and springs  1352 . The rail  1351  may be located in the primary housing  1306  and fixed with respect to the primary housing  1306 . The left optical module  1326  and the right optical module  1328  are connected to the rail  1351  and supported with respect to the rail  1351  to allow lateral (side-to-side) sliding of the left optical module  1326  and the right optical module  1328  with respect to the rail  1351  and with respect to the primary housing  1306 . The rail  1351  may be any structural element that allows the left optical module  1326  and the right optical module  1328  to be mounted to it in a manner that allows sliding. The rail  1351  may be a single structure or may include multiple structures. Sliding motion of the left optical module  1326  and the right optical module  1328  with respect to the rail includes sliding of the left optical module  1326  and the right optical module  1328  toward one another to decrease the IPD and sliding of the left optical module  1326  and the right optical module  1328  away from one another to increase the IPD. 
     The springs  1352  define an initial position for the left optical module  1326  and the right optical module  1328  in the disconnected position. The springs  1352  resist lateral movement of the left optical module  1326  and the right optical module  1328  relative to a neutral position. As an example, the neutral position may be a position in which the IPD is between a minimum IPD value and a maximum IPD value. In the illustrated implementation, the springs  1352  include a compression spring that is located laterally between the left optical module  1326  and the right optical module  1328  as well as compression springs that are located laterally outward from the left optical module  1326  and the right optical module  1328 . In an alternative implementation, the spring  1352  may be replaced by one or more springs that have a different configuration and are likewise configured to resist lateral movement of the left optical module  1326  and the right optical module  1328  away from a neutral position. 
     The first adjuster portion  1312  of the first device portion  1302  also includes a first group of magnetic connector components  1353  (magnetic and/or ferromagnetic components) and a second group of magnetic connector components  1354  (magnetic and/or ferromagnetic components). The first group of magnetic connector components  1353  includes one or more magnetic connector components that are connected to the left optical module  1326 . The second group of magnetic connector components  1354  includes one or more magnetic connector components that are connected to the right optical module  1328 . 
     The second adjuster portion  1336  of the second device portion  1304  includes a first group of magnetic connector components  1355  (magnetic and/or ferromagnetic components) and a second group of magnetic connector components  1356  (magnetic and/or ferromagnetic components). The first group of magnetic connector components  1355  includes one or more magnetic connector components that are connected to the secondary housing  1330  of the second device portion  1304  and positioned around the opening  1331  in general correspondence to the position of the left optical module  1326  and the first group of magnetic connector components  1353  of the first adjuster portion  1312  of the first device portion  1302 . The second group of magnetic connector components  1356  includes one or more magnetic connector components that are connected to the secondary housing  1330  of the second device portion  1304  and positioned around the opening  1331  in general correspondence to the position of the right optical module  1328  and the second group of magnetic connector components  1354  of the first adjuster portion  1312  of the first device portion  1302 . 
     The first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  of the second device portion  1304  are configured to shift the position of the left optical module  1326  and the right optical module  1328  by magnetic attraction with respect to the first group of magnetic connector components  1353  and the second group of magnetic connector components  1354  of the first adjuster portion  1312  during connection of the second device portion  1304  to the first device portion  1302 . Thus, the left optical module  1326  and the right optical module  1328  are moved laterally in dependence on an offset between the first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  of the second device portion  1304  with respect to the first group of magnetic connector components  1353  and the second group of magnetic connector components  1354  of the first device portion  1302 . Thus, connecting the second device portion  1304  to the first device portion  1302  shifts the position of the left optical module  1326  and the right optical module  1328  in dependence on the locations of the first group of magnetic connector components  1355  and the second first group of magnetic connector components  1356  to set the IPD based on the configuration of the second adjuster portion  1336  of the second device portion  1304 . 
     In some implementations, the second device portion  1304  is configured according to a predetermined IPD setting by placing the first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  of the second device portion  1304  at locations corresponding to the desired IPD setting during manufacture of the second device portion  1304 . 
     In other implementations, the IPD setting of the second device portion is user configurable. As one example, the first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  of the second device portion  1304  may be connectable and disconnectable to the secondary housing  1330  by mechanical connectors such as snaps, buttons, friction connectors, screws, bolts, or other connectors to allow the user to change the locations of the first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  to set a desired IPD setting. As another example, the first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  of the second device portion  1304  may include electropermanent magnets that can be changed from a first polarity to a second polarity (i.e., reversing the polar orientation of the magnetic field) by applying a magnetic field (e.g., by application of a current to a wire wound around part of the electropermanent magnet). By changing the polarities of certain components from the first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  of the second device portion  1304 , the IPD setting can be changed. 
     connectable and disconnectable to the secondary housing  1330  by mechanical connectors such as snaps, buttons, friction connectors, screws, bolts, or other connectors to allow the user to change the locations of the first group of magnetic connector components  1355  and the second group of magnetic connector components  1356  to set a desired IPD setting. 
     The second device portion  1304  is connectable to and disconnectable from the first device portion  1302  by engagement and disengagement of the first coupler portion  1310  of the first device portion  1302  with the second coupler portion  1334  of the second device portion  1304 . Connection and disconnection of the first coupler portion  1310  and the second coupler portion  1334  allows movement of the first device portion  1302  and the second device portion  1304  between the disconnected position ( FIG.  13   ) and the connected position ( FIG.  14   ). As previously described, the first coupler portion  1310  and the second coupler portion  1334  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  1336  of the second device portion  1304  is configured to cause the left optical module  1326  and the right optical module  1328  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  1304  to the first device portion  1302 . Several similarly configured second device portions may be made for use with the first device portion  1302 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  1302  with their own user-specific instance of the second device portion  1304 . 
       FIG.  15    is an illustration that shows a seventh example of a head-mounted device  1500  with a first device portion  1502  and a second device portion of the head-mounted device  1500  shown in a disconnected position.  FIG.  16    is an illustration that shows the seventh example of the head-mounted device  1500  with the first device portion  1502  and the second device portion  1504  of the head-mounted device  1500  shown in a connected position. 
     The head-mounted device  1500  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  1500 . 
     The first device portion  1502  of the head-mounted device  1500  includes a primary housing  1506 , a first coupler portion  1510 , a first adjuster portion  1512 , a left optical module  1526 , and a right optical module  1528 . The second device portion  1504  of the head-mounted device  1500  includes a secondary housing  1530 , a face cushion  1532 , a second coupler portion  1534 , and a second adjuster portion  1536 . Openings  1531  are formed in the secondary housing  1530  to allow visibility of the left optical module  1526  and the right optical module  1528  when the head-mounted device  1500  is worn by a user. Other components may be included in the first device portion  1502  and the second device portion  1504  of the head-mounted device  1500 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  1512  and the second adjuster portion  1536  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  1526  and an optical axis of the right optical module  1528  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  1512  is an assembly that includes an elastic support structure  1551 . The elastic support structure  1551  is connected to the primary housing  1506  of the first device portion  1502  and is also connected to the left optical module  1526  and the right optical module  1528 . The elastic support structure  1551  supports the left optical module  1526  and the right optical module  1528  in a neutral position relative to the primary housing  1506  of the first device portion  1502 . The elastic support structure  1551  is able to deform relative to the neutral position in response to external forces (e.g., by stretching and contracting), which allows the left optical module  1526  and the right optical module  1528  to move laterally (side-to-side direction) to allow for IPD adjustment, to move longitudinally (front-to-back direction) for eye relief adjustment, and/or to move vertically (up and down direction). When the external forces are released, the elastic nature of the elastic support structure  1551  urges the left optical module  1526  and the right optical module  1528  back to the neutral position. 
     The elastic support structure  1551  is a single-piece or multi-piece structure that is formed by a flexible and elastic material. As examples, the elastic support structure  1551  may be formed from synthetic rubber, silicone, or any other suitable flexible and elastic material. In the illustrated implementation, the elastic support structure  1551  is a sheet of flexible and elastic material that has its outer periphery mounted to the primary housing  1506  of the first device portion  1502 , and includes apertures through which the left optical module  1526  and the right optical module  1528  extend, and at which they are connected to the elastic support structure  1551 . In another implementation, the elastic support structure  1551  includes multiple bands or cords that extends between the primary housing  1506  and each of the left optical module  1526  and the right optical module  1528 . 
     The first adjuster portion  1512  of the first device portion  1502  also includes a first group of magnetic connector components  1553  (magnetic and/or ferromagnetic components) and a second group of magnetic connector components  1554  (magnetic and/or ferromagnetic components). The first group of magnetic connector components  1553  includes one or more magnetic connector components that are connected to the left optical module  1526 . The second group of magnetic connector components  1554  includes one or more magnetic connector components that are connected to the right optical module  1528 . 
     The second adjuster portion  1536  of the second device portion  1504  includes a first group of magnetic connector components  1555  (magnetic and/or ferromagnetic components) and a second group of magnetic connector components  1556  (magnetic and/or ferromagnetic components). The first group of magnetic connector components  1555  includes one or more magnetic connector components that are connected to the secondary housing  1530  of the second device portion  1504  and positioned around the opening  1531  in general correspondence to the position of the left optical module  1526  and the first group of magnetic connector components  1553  of the first adjuster portion  1512  of the first device portion  1502 . The second group of magnetic connector components  1556  includes one or more magnetic connector components that are connected to the secondary housing  1530  of the second device portion  1504  and positioned around the opening  1531  in general correspondence to the position of the right optical module  1528  and the second group of magnetic connector components  1554  of the first adjuster portion  1512  of the first device portion  1502 . 
     The first group of magnetic connector components  1555  and the second group of magnetic connector components  1556  of the second device portion  1504  are configured to shift the position of the left optical module  1526  and the right optical module  1528  by magnetic attraction with respect to the first group of magnetic connector components  1553  and the second group of magnetic connector components  1554  of the first adjuster portion  1512  during connection of the second device portion  1504  to the first device portion  1502 . Thus, the left optical module  1526  and the right optical module  1528  are moved laterally, longitudinally, and/or vertically by expansion and contraction of the elastic support structure  1551  in dependence on an offset between the first group of magnetic connector components  1555  and the second group of magnetic connector components  1556  of the second device portion  1504  with respect to the first group of magnetic connector components  1553  and the second group of magnetic connector components  1554  of the first device portion  1502 . Thus, connecting the second device portion  1504  to the first device portion  1502  shifts the position of the left optical module  1526  and the right optical module  1528  in dependence on the locations of the first group of magnetic connector components  1555  and the second first group of magnetic connector components  1556  to set the IPD based on the configuration of the second adjuster portion  1536  of the second device portion  1504 . 
     The second device portion  1504  is connectable to and disconnectable from the first device portion  1502  by engagement and disengagement of the first coupler portion  1510  of the first device portion  1502  with the second coupler portion  1534  of the second device portion  1504 . Connection and disconnection of the first coupler portion  1510  and the second coupler portion  1534  allows movement of the first device portion  1502  and the second device portion  1504  between the disconnected position ( FIG.  15   ) and the connected position ( FIG.  16   ). As previously described, the first coupler portion  1510  and the second coupler portion  1534  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  1536  of the second device portion  1504  is configured to cause the left optical module  1526  and the right optical module  1528  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  1504  to the first device portion  1502 . Several similarly configured second device portions may be made for use with the first device portion  1502 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  1502  with their own user-specific instance of the second device portion  1504 . 
       FIG.  17    is an illustration that shows an eighth example of a head-mounted device  1700  with a first device portion  1702  and a second device portion of the head-mounted device  1700  shown in a disconnected position.  FIG.  18    is an illustration that shows the eighth example of the head-mounted device  1700  with the first device portion  1702  and the second device portion  1704  of the head-mounted device  1700  shown in a connected position. 
     The head-mounted device  1700  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  1700 . 
     The first device portion  1702  of the head-mounted device  1700  includes a primary housing  1706 , a first coupler portion  1710 , a first adjuster portion  1712 , a left optical module  1726 , and a right optical module  1728 . The second device portion  1704  of the head-mounted device  1700  includes a secondary housing  1730 , a face cushion  1732 , a second coupler portion  1734 , and a second adjuster portion  1736 . An opening  1731  is formed in the secondary housing  1730  to allow visibility of the left optical module  1726  and the right optical module  1728  when the head-mounted device  1700  is worn by a user. Other components may be included in the first device portion  1702  and the second device portion  1704  of the head-mounted device  1700 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  1712  and the second adjuster portion  1736  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  1726  and an optical axis of the right optical module  1728  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  1712  is an assembly that includes a rail  1751  and pneumatic actuators  1753 . The rail  1751  may be located in the primary housing  1706  and fixed with respect to the primary housing  1706 . The left optical module  1726  and the right optical module  1728  are connected to the rail  1751  and supported with respect to the rail  1751  to allow lateral (side-to-side) sliding of the left optical module  1726  and the right optical module  1728  with respect to the rail  1751  and with respect to the primary housing  1706 . The rail  1751  may be any structural element that allows the left optical module  1726  and the right optical module  1728  to be mounted to it in a manner that allows sliding. The rail  1751  may be a single structure or may include multiple structures. Sliding motion of the left optical module  1726  and the right optical module  1728  with respect to the rail includes sliding of the left optical module  1726  and the right optical module  1728  toward one another to decrease the IPD and sliding of the left optical module  1726  and the right optical module  1728  away from one another to increase the IPD. 
     The pneumatic actuators  1753  control movement of the left optical module  1726  and the right optical module  1728  on the rail  1751 . As an example, the pneumatic actuators  1753  may be piston-cylinder actuators that are controlled to extend and retract using valves to supply pressurized air from an air source for extension and to release pressurized air for retraction. In the illustrated example, the pneumatic actuators  1753  include a first pneumatic actuator that is connected to the left optical module  1726  to move the left optical module  1726  along the rail  1751  and a second pneumatic actuator that is connected to the right optical module  1728  to move the right optical module  1728  along the rail  1751 . 
     The second adjuster portion  1736  also includes a first stop surface  1755  and a second stop surface  1756 . The first stop surface  1755  and the second stop surface  1756  are positioned (fixed or adjustably) on the secondary housing  1730  at locations that correspond to a desired IPD between the left optical module  1726  and the right optical module  1728 . Upon connection of the second device portion  1704  to the first device portion  1702 , the pneumatic actuators  1753  are operated to extend and move the left optical module  1726  and the right optical module  1728  laterally inward until the left optical module  1726  reaches and engages the first stop surface  1755  and the right optical module  1728  reaches and engages the second stop surface  1756 . Engagement with the first stop surface  1755  and the second stop surface  1756  ceases inward movement of the left optical module  1726  and the right optical module  1728 , thereby setting the IPD according to the locations of the first stop surface  1755  and the second stop surface  1756 . 
     The second device portion  1704  is connectable to and disconnectable from the first device portion  1702  by engagement and disengagement of the first coupler portion  1710  of the first device portion  1702  with the second coupler portion  1734  of the second device portion  1704 . Connection and disconnection of the first coupler portion  1710  and the second coupler portion  1734  allows movement of the first device portion  1702  and the second device portion  1704  between the disconnected position ( FIG.  17   ) and the connected position ( FIG.  18   ). As previously described, the first coupler portion  1710  and the second coupler portion  1734  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  1736  of the second device portion  1704  is configured to cause the left optical module  1726  and the right optical module  1728  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  1704  to the first device portion  1702 . Several similarly configured second device portions may be made for use with the first device portion  1702 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  1702  with their own user-specific instance of the second device portion  1704 . 
       FIG.  19    is an illustration that shows a ninth example of a head-mounted device  1900  with a first device portion  1902  and a second device portion of the head-mounted device  1900  shown in a disconnected position.  FIG.  20    is an illustration that shows the ninth example of the head-mounted device  1900  with the first device portion  1902  and the second device portion  1904  of the head-mounted device  1900  shown in a connected position. 
     The head-mounted device  1900  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  1900 . 
     The first device portion  1902  of the head-mounted device  1900  includes a primary housing  1906 , a first coupler portion  1910 , a first adjuster portion  1912 , a left optical module  1926 , and a right optical module  1928 . The second device portion  1904  of the head-mounted device  1900  includes a secondary housing  1930 , a face cushion  1932 , a second coupler portion  1934 , and a second adjuster portion  1936 . An opening  1931  is formed in the secondary housing  1930  to allow visibility of the left optical module  1926  and the right optical module  1928  when the head-mounted device  1900  is worn by a user. Other components may be included in the first device portion  1902  and the second device portion  1904  of the head-mounted device  1900 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  1912  and the second adjuster portion  1936  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  1926  and an optical axis of the right optical module  1928  to be adjusted between a minimum IPD and a maximum IPD. 
     The first adjuster portion  1912  allows manual adjustment of the position of the left optical module  1926  and the right optical module  1928 . In the illustrated example, the first adjuster portion  1912  is an assembly that includes a rail  1951  and adjuster knobs  1953   a  that turn lead screws  1953   b . The rail  1951  may be located in the primary housing  1906  and fixed with respect to the primary housing  1906 . The left optical module  1926  and the right optical module  1928  are connected to the rail  1951  and supported with respect to the rail  1951  to allow lateral (side-to-side) sliding of the left optical module  1926  and the right optical module  1928  with respect to the rail  1951  and with respect to the primary housing  1906 . The rail  1951  may be any structural element that allows the left optical module  1926  and the right optical module  1928  to be mounted to it in a manner that allows sliding. The rail  1951  may be a single structure or may include multiple structures. Sliding motion of the left optical module  1926  and the right optical module  1928  with respect to the rail includes sliding of the left optical module  1926  and the right optical module  1928  toward one another to decrease the IPD and sliding of the left optical module  1926  and the right optical module  1928  away from one another to increase the IPD. 
     The adjuster knobs  1953   a  and the lead screws  1953   b  control movement of the left optical module  1926  and the right optical module  1928  on the rail  1951 . One of the adjuster knobs  1953   a  and a corresponding one of the lead screws  1953   b  is connected to the left optical module  1926  to move the left optical module  1926  laterally when the corresponding one of the adjuster knobs  1953   a  is turned by the user. One of the adjuster knobs  1953   a  and a corresponding one of the lead screws  1953   b  is connected to the right optical module  1928  to move the right optical module  1928  laterally when the corresponding one of the adjuster knobs  1953   a  is turned by the user. The adjuster knobs  1953   a  may include clutches that slip in response to a predetermined amount of resistance (e.g., applied torque exceeds a maximum torque value) to stop motion when motion is resisted (e.g., by a stop surface). 
     The second adjuster portion  1936  also includes a first stop surface  1955  and a second stop surface  1956 . The first stop surface  1955  and the second stop surface  1956  are positioned (fixed or adjustably) on the secondary housing  1930  at locations that correspond to a desired IPD between the left optical module  1926  and the right optical module  1928 . Upon connection of the second device portion  1904  to the first device portion  1902 , the adjuster knobs  1953   a  are operated to move the left optical module  1926  and the right optical module  1928  laterally inward until the left optical module  1926  reaches and engages the first stop surface  1955  and the right optical module  1928  reaches and engages the second stop surface  1956 . Engagement with the first stop surface  1955  and the second stop surface  1956  ceases inward movement of the left optical module  1926  and the right optical module  1928  (e.g., by slipping of clutches included in the adjuster knobs  1953   a ), thereby setting the IPD according to the locations of the first stop surface  1955  and the second stop surface  1956 . 
     The second device portion  1904  is connectable to and disconnectable from the first device portion  1902  by engagement and disengagement of the first coupler portion  1910  of the first device portion  1902  with the second coupler portion  1934  of the second device portion  1904 . Connection and disconnection of the first coupler portion  1910  and the second coupler portion  1934  allows movement of the first device portion  1902  and the second device portion  1904  between the disconnected position ( FIG.  19   ) and the connected position ( FIG.  20   ). As previously described, the first coupler portion  1910  and the second coupler portion  1934  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  1936  of the second device portion  1904  is configured to cause the left optical module  1926  and the right optical module  1928  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  1904  to the first device portion  1902 . Several similarly configured second device portions may be made for use with the first device portion  1902 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  1902  with their own user-specific instance of the second device portion  1904 . 
       FIG.  21    is an illustration that shows a tenth example of a head-mounted device  2100  with a first device portion  2102  and a second device portion of the head-mounted device  2100  shown in a disconnected position.  FIG.  22    is an illustration that shows the tenth example of the head-mounted device  2100  with the first device portion  2102  and the second device portion  2104  of the head-mounted device  2100  shown in a connected position. 
     The head-mounted device  2100  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  2100 . 
     The first device portion  2102  of the head-mounted device  2100  includes a primary housing  2106 , a first coupler portion  2110 , a first adjuster portion  2112 , a left optical module  2126 , and a right optical module  2128 . The second device portion  2104  of the head-mounted device  2100  includes a secondary housing  2130 , a face cushion  2132 , a second coupler portion  2134 , and a second adjuster portion  2136 . An opening  2131  is formed in the secondary housing  2130  to allow visibility of the left optical module  2126  and the right optical module  2128  when the head-mounted device  2100  is worn by a user. Other components may be included in the first device portion  2102  and the second device portion  2104  of the head-mounted device  2100 , including components that were described with respect to the head-mounted device  100 . 
     The first adjuster portion  2112  and the second adjuster portion  2136  cooperate to define an IPD adjustment assembly. The IPD adjustment assembly allows a distance between an optical axis of the left optical module  2126  and an optical axis of the right optical module  2128  to be adjusted between a minimum IPD and a maximum IPD. 
     In the illustrated example, the first adjuster portion  2112  is an assembly that includes a rail  2151 , springs  2152 , and flexible connectors  2153 . The rail  2151  may be located in the primary housing  2106  and fixed with respect to the primary housing  2106 . The left optical module  2126  and the right optical module  2128  are connected to the rail  2151  and supported with respect to the rail  2151  to allow lateral (side-to-side) sliding of the left optical module  2126  and the right optical module  2128  with respect to the rail  2151  and with respect to the primary housing  2106 . The rail  2151  may be any structural element that allows the left optical module  2126  and the right optical module  2128  to be mounted to it in a manner that allows sliding. The rail  2151  may be a single structure or may include multiple structures. Sliding motion of the left optical module  2126  and the right optical module  2128  with respect to the rail includes sliding of the left optical module  2126  and the right optical module  2128  toward one another to decrease the IPD and sliding of the left optical module  2126  and the right optical module  2128  away from one another to increase the IPD. 
     The springs  2152  define an initial position for the left optical module  2126  and the right optical module  2128  in the disconnected position. The springs  2152  are located laterally outward from each of the left optical module  2126  and the right optically module  2128  to urge the left optical module  2126  and the right optical module  2128  laterally inward and to resist laterally outward movement of the left optical module  2126  and the right optical module  2128 . In the illustrated example, the springs  2152  are compression springs, but different numbers of springs and/or types of springs may be used instead to similar effect. 
     The flexible connectors  2153  are flexible elements that are each connected to one of the left optical module  2126  and the right optical module  2128 , and are also connected to or are part of the support structure that secures the head-mounted device  2100  to the user&#39;s head. As an example, the flexible connectors  2153  may be, or may be connected to, end portions of a headband that supports the head-mounted device  2100 . When the user wears the head-mounted device  2100 , the support structure is extended and applies tension to the flexible connectors  2153 , which causes the left optical module  2126  and the right optical module  2128  to move laterally outward in opposition to the forces applied by the springs  2152 . 
     In the illustrated example, the flexible connectors  2153  are shown as part of the first device portion  2102 , by extending into to the primary housing  2106  of the first device portion  2102  and being directly connected to the left optical module  2126  and the right optical module  2128 . In an alternative implementation, the flexible connectors  2153  (and thus the support structure that secures the head-mounted device  2100  to the user&#39;s head) could be part of the second device portion  2104 , in which case the flexible connectors  2153  would be indirectly connected to the left optical module  2126  and the right optical module  2128  by components located in the second device portion  2104 . 
     The second adjuster portion  2136  also includes a first stop surface  2155  and a second stop surface  2156 . The first stop surface  2155  and the second stop surface  2156  are positioned (fixed or adjustably) on the secondary housing  2130  at locations that correspond to a desired IPD between the left optical module  2126  and the right optical module  2128 . The first stop surface  2155  and the second stop surface  2156  are located laterally outward from the left optical module  2126  and the right optical module  2128  when no tension is applied to the flexible connectors  2153 . When tension is applied to the flexible connectors  2153 , the left optical module  2126  and the right optical module  2128  move laterally outward until the left optical module  2126  reaches and engages the first stop surface  2155  and the right optical module  2128  reaches and engages the second stop surface  2156 . Engagement with the first stop surface  2155  and the second stop surface  2156  ceases outward movement of the left optical module  2126  and the right optical module  2128 . 
     The second device portion  2104  is connectable to and disconnectable from the first device portion  2102  by engagement and disengagement of the first coupler portion  2110  of the first device portion  2102  with the second coupler portion  2134  of the second device portion  2104 . Connection and disconnection of the first coupler portion  2110  and the second coupler portion  2134  allows movement of the first device portion  2102  and the second device portion  2104  between the disconnected position ( FIG.  21   ) and the connected position ( FIG.  22   ). As previously described, the first coupler portion  2110  and the second coupler portion  2134  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     The second adjuster portion  2136  of the second device portion  2104  is configured to cause the left optical module  2126  and the right optical module  2128  of the first device portion to move to a specific lateral spacing with respect to each other in the connected position, which corresponds to a specific IPD that is therefore set by connection of the second device portion  2104  to the first device portion  2102 . Several similarly configured second device portions may be made for use with the first device portion  2102 , and each of the several similarly configured device portions may have a differently configured second adjuster portion (by a fixed configuration or adjustable configuration) that corresponds to a specific IPD. This allows each of several users to use the first device portion  2102  with their own user-specific instance of the second device portion  2104 . 
       FIG.  23    is an illustration that shows an eleventh example of a head-mounted device  2300  with a first device portion  2302  and a second device portion of the head-mounted device  2300  shown in a disconnected position.  FIG.  24    is an illustration that shows the eleventh example of the head-mounted device  2300  with the first device portion  2302  and the second device portion  2304  of the head-mounted device  2300  shown in a connected position. 
     The head-mounted device  2300  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  2300 . 
     The first device portion  2302  of the head-mounted device  2300  includes a primary housing  2306 , electronic components  2307 , and a first coupler portion  2310 . The second device portion  2304  of the head-mounted device  2300  includes a left optical module  2326 , a right optical module  2328 , a secondary housing  2330 , a face cushion  2332 , a second coupler portion  2334 , and an IPD adjustment assembly  2336 . Other components may be included in the first device portion  2302  and the second device portion  2304  of the head-mounted device  2300 , including components that were described with respect to the head-mounted device  100 . 
     The electronic components  2307  may include components described with respect to the first device portion  102  of the head-mounted device  100 . As an example, the electronic components may include components equivalent to the processor  114 , the memory  116 , the storage device  118 , the communications device  120 , the sensors  122 , and/or the power source  124  of the first device portion  102  of the head-mounted device  100 . When the first device portion  2302  is connected to the second device portion  2304  some or all of these components are electrically connected, by a wired connection or a wireless connection, to the left optical module  2326  and the right optical module  2328  to cause display of content. 
     The IPD adjustment assembly  2336  allows a distance between an optical axis of the left optical module  2326  and an optical axis of the right optical module  2328  to be adjusted between a minimum IPD and a maximum IPD. The IPD adjustment assembly is located in the secondary housing  2330  of the second device portion  2304  and adjustment is not dependent on connection of the second device portion  2304  to the first device portion  2302 . 
     The IPD adjustment assembly  2336  includes mechanical or electrical adjustment components that move the left optical module  2326  and the right optical module  2328  to change the lateral spacing between them. In the illustrated example, the IPD adjustment assembly  2336  includes rails that support the optical modules, and lead screws that cause motion of the optical modules when rotated by electric motors. Other configurations can be used. 
     The second device portion  2304  is connectable to and disconnectable from the first device portion  2302  by engagement and disengagement of the first coupler portion  2310  of the first device portion  2302  with the second coupler portion  2334  of the second device portion  2304 . Connection and disconnection of the first coupler portion  2310  and the second coupler portion  2334  allows movement of the first device portion  2302  and the second device portion  2304  between the disconnected position ( FIG.  23   ) and the connected position ( FIG.  24   ). As previously described, the first coupler portion  2310  and the second coupler portion  2334  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
       FIG.  25    is an illustration that shows an eleventh example of a head-mounted device  2500  with a first device portion  2502  and a second device portion of the head-mounted device  2500  shown in a disconnected position.  FIG.  26    is an illustration that shows the eleventh example of the head-mounted device  2500  with the first device portion  2502  and the second device portion  2504  of the head-mounted device  2500  shown in a connected position. 
     The head-mounted device  2500  may be implemented in the manner described with respect to the head-mounted device  100  except as stated otherwise herein, and the description of the head-mounted device  100  and its components from  FIGS.  1 - 2    is hereby incorporated by reference in the description of the head-mounted device  2500 . 
     The first device portion  2502  of the head-mounted device  2500  includes a primary housing  2506 , a first coupler portion  2510 , an IPD adjustment assembly  2512 , a left optical module  2526 , and a right optical module  2528 . The second device portion  2504  of the head-mounted device  2500  includes a secondary housing  2530 , a face cushion  2532 , a second coupler portion  2534 , and an adjustment indicator  2536 . An opening  2531  is formed in the secondary housing  2530  to allow visibility of the left optical module  2526  and the right optical module  2528  when the head-mounted device  2500  is worn by a user. Other components may be included in the first device portion  2502  and the second device portion  2504  of the head-mounted device  2500 , including components that were described with respect to the head-mounted device  100 . 
     The IPD adjustment assembly  2512  allows a distance between an optical axis of the left optical module  2526  and an optical axis of the right optical module  2528  to be adjusted between a minimum IPD and a maximum IPD. The IPD adjustment assembly  2512  is located in the primary housing  2506  of the first device portion  2502 . Adjustment is not dependent on mechanical interaction during connection of the second device portion  2504  to the first device portion  2502 . Instead, the IPD adjustment assembly  2512  determines positions for the left optical module  2526  and the right optical module  2528  based on information provided by the adjustment indicator  2536  that is included in the second device portion  2504 , as will be explained. 
     The IPD adjustment assembly  2512  includes electrical adjustment components that move the left optical module  2526  and the right optical module  2528  to change the lateral spacing between them. In the illustrated example, the IPD adjustment assembly  2512  includes a rail  2551  that supports the left optical module  2526  and the right optical module  2528 , and lead screws  2552  that cause motion of the left optical module  2526  and the right optical module  2528  when rotated by electric motors  2553 . Other configurations can be used. 
     The IPD adjustment assembly  2512  also includes an adjustment controller  2554  that controls operation of the electric motors  2553  or other prime mover that drives adjustment of the IPD setting. The IPD adjustment controller may be a computing device or other control device that receives information describing an IPD setting from the adjustment indicator  2536  of the second device portion  2504  and causes movement of the left optical module  2526  and the right optical module  2528  in accordance with the information in response to connection of the second device portion  2504  to the first device portion  2502 . 
     In one implementation, the adjustment indicator  2536  includes an information storage device and transmits information to the adjustment controller  2554  using wireless communication, for example, in accordance with radio-frequency identification techniques and standards, near field communication techniques and standards, or any other suitable wireless data transmission techniques and standards. In one implementation, the adjustment indicator  2536  includes indicia that are readable by the adjustment controller  2554 , such as by obtaining images of visible markings (e.g., a bar code or QR code) that are included in the adjustment indicator, or by obtaining images or otherwise perceiving non-visible markings, such as infrared indicators that are included in the adjustment indicator  2536 . Other techniques can be used. 
     The second device portion  2504  is connectable to and disconnectable from the first device portion  2502  by engagement and disengagement of the first coupler portion  2510  of the first device portion  2502  with the second coupler portion  2534  of the second device portion  2504 . Connection and disconnection of the first coupler portion  2510  and the second coupler portion  2534  allows movement of the first device portion  2502  and the second device portion  2504  between the disconnected position ( FIG.  25   ) and the connected position ( FIG.  26   ). As previously described, the first coupler portion  2510  and the second coupler portion  2534  may be physical connection structures, magnetic connection structures, or other types of connection structures. 
     When the second device portion  2504  is connected to the first device portion  2502 , the adjustment controller  2554  determines the correct settings for IPD adjustment and/or other adjustments using information obtained from the adjustment indicator  2536 . The adjustment controller  2554  then controls movement of the left optical module  2526  and the right optical module  2528  according to the obtained information. 
       FIG.  27    is a side view assembly that shows an adjuster assembly  2760  that is configured to adjust the position of an optical module  2726  for IPD adjustment, vertical adjustment, and eye relief adjustment. The adjuster assembly  2760  may be included in any of the head-mounted devices described with respect to  FIGS.  1 - 26   , for example as a part of the first device portion of those devices, and used in connection with the left and right optical modules of those devices. 
     The adjuster assembly  2760  includes a first adjustment stage  2761 , a second adjustment stage  2762 , and a third adjustment stage  2763 . Movement of the optical module  2726  may be performed using mechanical or electrical adjusters as described elsewhere herein. 
     The first adjustment stage  2761  is an IPD adjustment stage that allows the optical module  2726  to move laterally. In the illustrated example, the first adjustment stage  2761  includes rails  2751   a  that are connected to a device housing (not shown) and a first carriage  2753   a  that slides on the rails. Other components may be included per the description of the first adjuster portion  112  or the first adjuster portions described in  FIGS.  3 - 26   . 
     The second adjustment stage  2762  is a vertical adjustment stage that allows the optical module  2726  to move vertically. In the illustrated example, the second adjustment stage  2762  includes rails  2751   b  that are fixedly connected to the first carriage  2753   a , a second carriage  2753   b  that slides on the rails  2751   b , and springs  2752   b  that bias the second carriage  2753   b  to a desired initial position relative to the first carriage  2753   a . Other components may be included per the description of the first adjuster portion  112  or the first adjuster portions described in  FIGS.  3 - 26   . 
     The third adjustment stage  2763  is an eye-relief adjustment stage that allows the optical module  2726  to move longitudinally (toward and away from the user). In the illustrated example, the third adjustment stage  2763  includes rails  2751   c  that are fixedly connected to the second carriage  2753   b , a third carriage  2753   c  that slides on the rails  2751   c , and springs  2752   c  that bias the third carriage  2753   c  to a desired initial position relative to the second carriage  2753   b . The optical module  2726  is connected to the third carriage  2753   c . Other components may be included per the description of the first adjuster portion  112  or the first adjuster portions described in  FIGS.  3 - 26   . 
       FIG.  28    is a side view assembly that shows an adjuster assembly  2860  that is configured to adjust the position of an optical module  2826  for IPD adjustment using gross and find adjustment. The adjuster assembly  2860  may be included in any of the head-mounted devices described with respect to  FIGS.  1 - 22   , for example as a part of the first device portion of those devices, and used in connection with the left and right optical modules of those devices. 
     The adjuster assembly  2860  includes a gross adjustment stage  2861  and a fine adjustment stage  2862 . 
     The gross adjustment stage  2861  may be implemented according to the first adjuster portion of any of the implementations shown in  FIGS.  1 - 22    to mechanically adjust the position of the optical module  2826  in response to connection of a second device portion to a first device portion in a two part head-mounted device. In the illustrated example, the gross adjustment stage includes a rail  2851 , springs  2852  that position the optical module  2826  on the rail  2851  absent an external force, and a first carriage  2853   a  that slides on the rail  2851  and is moved by the springs  2852 . 
     The fine adjustment stage  2862  is configured to be controlled independent of the gross adjustment stage  2861  and has a small range of travel. In the illustrated example, the fine adjustment stage  2862  is electronically controlled in that it moves a second carriage  2853   b  along a lead screw  2854  using electric motors  2855 . The lead screw  2854  and electric motors  2855  are connected to the first carriage  2853   a  and the second carriage  2853   b  is connected to the optical module  2826 . 
     In some implementations, fine adjustment can be performed using very small actuators in lieu of the electric motors  2855  shown in the illustrated example. In one implementation, piezoelectric actuators are used. In another example, resonant frequency-based actuators are used. 
     A physical environment refers to a physical world that people can sense and/or interact with without aid of electronic systems. Physical environments, such as a physical park, include physical articles, such as physical trees, physical buildings, and physical people. People can directly sense and/or interact with the physical environment, such as through sight, touch, hearing, taste, and smell. 
     In contrast, a computer-generated reality (CGR) environment refers to a wholly or partially simulated environment that people sense and/or interact with via an electronic system. In CGR, a subset of a person&#39;s physical motions, or representations thereof, are tracked, and, in response, one or more characteristics of one or more virtual objects simulated in the CGR environment are adjusted in a manner that comports with at least one law of physics. For example, a CGR system may detect a person&#39;s head turning and, in response, adjust graphical content and an acoustic field presented to the person in a manner similar to how such views and sounds would change in a physical environment. In some situations (e.g., for accessibility reasons), adjustments to characteristic(s) of virtual object(s) in a CGR environment may be made in response to representations of physical motions (e.g., vocal commands). 
     A person may sense and/or interact with a CGR object using any one of their senses, including sight, sound, touch, taste, and smell. For example, a person may sense and/or interact with audio objects that create three-dimensional or spatial audio environment that provides the perception of point audio sources in three-dimensional space. In another example, audio objects may enable audio transparency, which selectively incorporates ambient sounds from the physical environment with or without computer-generated audio. In some CGR environments, a person may sense and/or interact only with audio objects. 
     Examples of CGR include virtual reality and mixed reality. 
     A virtual reality (VR) environment refers to a simulated environment that is designed to be based entirely on computer-generated sensory inputs for one or more senses. A VR environment comprises a plurality of virtual objects with which a person may sense and/or interact. For example, computer-generated imagery of trees, buildings, and avatars representing people are examples of virtual objects. A person may sense and/or interact with virtual objects in the VR environment through a simulation of the person&#39;s presence within the computer-generated environment, and/or through a simulation of a subset of the person&#39;s physical movements within the computer-generated environment. 
     In contrast to a VR environment, which is designed to be based entirely on computer-generated sensory inputs, a mixed reality (MR) environment refers to a simulated environment that is designed to incorporate sensory inputs from the physical environment, or a representation thereof, in addition to including computer-generated sensory inputs (e.g., virtual objects). On a virtuality continuum, a mixed reality environment is anywhere between, but not including, a wholly physical environment at one end and virtual reality environment at the other end. 
     In some MR environments, computer-generated sensory inputs may respond to changes in sensory inputs from the physical environment. Also, some electronic systems for presenting an MR environment may track location and/or orientation with respect to the physical environment to enable virtual objects to interact with real objects (that is, physical articles from the physical environment or representations thereof). For example, a system may account for movements so that a virtual tree appears stationery with respect to the physical ground. 
     Examples of mixed realities include augmented reality and augmented virtuality. 
     An augmented reality (AR) environment refers to a simulated environment in which one or more virtual objects are superimposed over a physical environment, or a representation thereof. For example, an electronic system for presenting an AR environment may have a transparent or translucent display through which a person may directly view the physical environment. The system may be configured to present virtual objects on the transparent or translucent display, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. Alternatively, a system may have an opaque display and one or more imaging sensors that capture images or video of the physical environment, which are representations of the physical environment. The system composites the images or video with virtual objects, and presents the composition on the opaque display. A person, using the system, indirectly views the physical environment by way of the images or video of the physical environment, and perceives the virtual objects superimposed over the physical environment. As used herein, a video of the physical environment shown on an opaque display is called “pass-through video,” meaning a system uses one or more image sensor(s) to capture images of the physical environment, and uses those images in presenting the AR environment on the opaque display. Further alternatively, a system may have a projection system that projects virtual objects into the physical environment, for example, as a hologram or on a physical surface, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. 
     An augmented reality environment also refers to a simulated environment in which a representation of a physical environment is transformed by computer-generated sensory information. For example, in providing pass-through video, a system may transform one or more sensor images to impose a select perspective (e.g., viewpoint) different than the perspective captured by the imaging sensors. As another example, a representation of a physical environment may be transformed by graphically modifying (e.g., enlarging) portions thereof, such that the modified portion may be representative but not photorealistic versions of the originally captured images. As a further example, a representation of a physical environment may be transformed by graphically eliminating or obfuscating portions thereof. 
     An augmented virtuality (AV) environment refers to a simulated environment in which a virtual or computer-generated environment incorporates one or more sensory inputs from the physical environment. The sensory inputs may be representations of one or more characteristics of the physical environment. For example, an AV park may have virtual trees and virtual buildings, but people with faces photorealistically reproduced from images taken of physical people. As another example, a virtual object may adopt a shape or color of a physical article imaged by one or more imaging sensors. As a further example, a virtual object may adopt shadows consistent with the position of the sun in the physical environment. 
     There are many different types of electronic systems that enable a person to sense and/or interact with various CGR environments. Examples include head-mounted systems, projection-based systems, heads-up displays (HUDs), vehicle windshields having integrated display capability, windows having integrated display capability, displays formed as lenses designed to be placed on a person&#39;s eyes (e.g., similar to contact lenses), headphones/earphones, speaker arrays, input systems (e.g., wearable or handheld controllers with or without haptic feedback), smartphones, tablets, and desktop/laptop computers. A head-mounted system may have one or more speaker(s) and an integrated opaque display. Alternatively, a head-mounted system may be configured to accept an external opaque display (e.g., a smartphone). The head-mounted system may incorporate one or more imaging sensors to capture images or video of the physical environment, and/or one or more microphones to capture audio of the physical environment. Rather than an opaque display, a head-mounted system may have a transparent or translucent display. The transparent or translucent display may have a medium through which light representative of images is directed to a person&#39;s eyes. The display may utilize digital light projection, OLEDs, LEDs, uLEDs, liquid crystal on silicon, laser scanning light source, or any combination of these technologies. The medium may be an optical waveguide, a hologram medium, an optical combiner, an optical reflector, or any combination thereof. In one embodiment, the transparent or translucent display may be configured to become opaque selectively. Projection-based systems may employ retinal projection technology that projects graphical images onto a person&#39;s retina. Projection systems also may be configured to project virtual objects into the physical environment, for example, as a hologram or on a physical surface. 
     As described above, one aspect of the present technology is the gathering and use of data available from various sources to adjust features of a head-mounted device. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, twitter ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, a user profile may be established that stores adjustment related information that allows the head-mounted device to be adjusted for a user upon connection of the user-specific second device portion to the first device portion. Accordingly, use of such personal information data enhances the user&#39;s experience. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of storing a user profile to allow adjustment of features of a head-mounted device, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In another example, users can select not to provide data regarding usage of specific applications. In yet another example, users can select to limit the length of time that data is maintained or entirely prohibit the development of a profile. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an app that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, adjustments may be performed using purely mechanical means or using information that is stored only on the device (e.g., on the second device portion).

Metadata:
Filing Date: 20200915
Publication Date: 20231010
Grant Date: 20231010
Priority Date: 20190916
Inventors: MIRABELLA, ANNA V.
LIN, WEY-JIUN
TAO, Jia
ZIMMERMAN, AIDAN N.
SAUERS, JASON C.
MONTEVIRGEN, ANTHONY S.
GALLAHER, ANDREW
HOBSON, Phil M.
JO, YOONHOO
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B30/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B7/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B30/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B27/0176", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0134", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B27/0172", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/0176", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B2027/0181", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/002", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 74869507