Apparatuses, systems, and methods for determining interpupillary distances of head-mounted displays

1. A head-mounted-display system comprising:

a support assembly;

a pair of display assemblies moveably coupled to the support assembly such that the pair of display assemblies are moveable between a plurality of positions corresponding to a plurality of user interpupillary distances, the pair of display assemblies respectively defining separate viewing regions for a user's right and left eyes, each of the pair of display assemblies comprising:

a lens; and

a display screen having a display area that projects image light from a front surface of the display screen toward the lens; and

a detection subsystem comprising:

at least one position sensor that measures emissions from a tracked region located on a back surface or a peripheral side surface of at least one display assembly of the pair of display assemblies; and

a determination module that determines a positional relationship between the pair of display assemblies based on the emissions measured by the at least one position sensor.

2. The head-mounted-display system of claim 1 , wherein the positional relationship between the pair of display assemblies comprises a user interpupillary distance corresponding to a position of the pair of display assemblies with respect to each other.

3. The head-mounted-display system of claim 1 , wherein the at least one position sensor comprises at least one optical sensor that measures quantities of light emitted from the tracked region of the at least one display assembly.

4. The head-mounted-display system of claim 3 , wherein:

the tracked region of the at least one display assembly comprises a tracking opening defined in a back light-blocking layer of the display screen of the at least one display assembly that is disposed opposite the front surface of the display screen of the at least one display assembly; and

a portion of light generated by the display screen passes through the tracking opening.

5. The head-mounted-display system of claim 4 , wherein:

the support assembly comprises a dividing member extending between the display screen of the at least one display assembly and the at least one optical sensor; and

a dividing-member opening is defined in a portion of the dividing member that at least partially overlaps the tracking opening defined in the back light-blocking layer of the display screen of the at least one display assembly.

6. The head-mounted-display system of claim 5 , wherein:

the tracking opening defined in the back light-blocking layer of the display screen of the at least one display assembly extends longitudinally in a first direction parallel to a back surface of the back light-blocking layer; and

the dividing-member opening defined in the dividing member of the support assembly extends longitudinally in a second direction that is nonparallel to the first direction.

7. The head-mounted-display system of claim 3 , further comprising at least one reflective element for reflecting at least a portion of the light emitted from the tracked region of the at least one display assembly toward the at least one optical sensor, wherein the at least one reflective element is disposed outside the pair of display assemblies.

8. The head-mounted-display system of claim 3 , further comprising at least one collimator for directing at least a portion of light emitted from the tracked region of the at least one display assembly toward the at least one optical sensor.

9. The head-mounted-display system of claim 1 , wherein:

the tracked region of the at least one display assembly comprises a magnetic element; and

the at least one position sensor comprises at least one magnetic field sensor that measures a magnetic field emitted by the magnetic element.

10. The head-mounted-display system of claim 9 , wherein the at least one magnetic field sensor comprises a magnetoresistive sensor.

11. The head-mounted-display system of claim 1 , wherein:

the at least one position sensor comprises a plurality of discrete position sensors that each measure the emissions from the tracked region of the at least one display assembly; and

the determination module determines the positional relationship between the pair of display assemblies based on the emissions measured by the plurality of discrete position sensors.

12. The head-mounted-display system of claim 1 , wherein the tracked region of the at least one display assembly is located outside the display area.

13. The head-mounted-display system of claim 1 , wherein the emissions from the tracked region of the at least one display assembly comprise light emitted from a back surface of the display screen of the at least one display assembly that is opposite the front surface of the display screen of the at least one display assembly through which image light is projected.

14. The head-mounted-display system of claim 1 , wherein the at least one position sensor is disposed on a printed circuit board.

15. The head-mounted-display system of claim 1 , further comprising a display adjustment assembly for adjusting positions of the pair of display assemblies with respect to each other.

16. A head-mounted-display device comprising:

a display housing;

a support assembly mounted to the display housing;

a pair of display assemblies moveably coupled to the support assembly such that the pair of display assemblies are moveable between a plurality of positions corresponding to a plurality of user interpupillary distances, the pair of display assemblies respectively defining separate viewing regions for a user's right and left eyes, each of the pair of display assemblies comprising:

a lens; and

a display screen having a display area that projects image light from a front surface of the display screen toward the lens; and

a detection subsystem comprising:

at least one position sensor that measures emissions from a tracked region located on a back surface or a peripheral side surface of at least one display assembly of the pair of display assemblies; and

a determination module that determines a positional relationship between the pair of display assemblies based on the emissions measured by the at least one position sensor.

17. The head-mounted-display device of claim 16 , wherein:

the display housing comprises a viewing opening and an end surface disposed opposite the viewing opening; and

the at least one position sensor is disposed between the tracked region of the at least one display assembly and the end surface of the display housing.

18. A method comprising:

measuring, by at least one position sensor of a detection subsystem, emissions from a tracked region located on a back surface or a peripheral side surface of at least one display assembly of a pair of display assemblies of a head-mounted-display system, the pair of display assemblies moveably coupled to a support assembly such that the pair of display assemblies are moveable between a plurality of positions corresponding to a plurality of user interpupillary distances, the pair of display assemblies respectively defining separate viewing regions for a user's right and left eyes, each of the pair of display assemblies comprising:

a lens; and

a display screen having a display area that projects image light from a front surface of the display screen toward the lens; and

determining, by a determination module, a positional relationship between the pair of display assemblies based on the emissions measured by the at least one position sensor.

19. The method of claim 18 , further comprising:

adjusting, by a display adjustment assembly, positions of the pair of display assemblies with respect to each other;

measuring, by the at least one position sensor of the detection subsystem, additional emissions from the tracked region of the at least one display assembly of the pair of display assemblies disposed in the adjusted positions; and

determining, by the determination module, an adjusted positional relationship between the pair of display assemblies based on the additional emissions measured by the at least one position sensor.

20. The method of claim 18 , wherein the at least one position sensor comprises at least one of an optical sensor and a magnetic field sensor.