Magnetic interpupillary distance adjustment

1. A system for interpupillary distance (IPD) adjustment comprising:

a first nonmoving component;

a sliding assembly comprising a button; and

a pair of magnets, wherein a first magnet of the pair of magnets is coupled to the sliding assembly;

wherein:

the pair of magnets are configured to exert a magnetic force, in a first direction, on the sliding assembly to press the sliding assembly against the first nonmoving component to lock the sliding assembly to the first nonmoving component; and

the sliding assembly is configured to, when the button of the sliding assembly is pushed by a force in a second direction opposite the first direction of the magnetic force, disengage with the first nonmoving component and become slidable with respect to the first nonmoving component.

2. The system of claim 1 , further comprising a second nonmoving component, wherein:

the sliding assembly is positioned between the first nonmoving component and the second nonmoving component;

a second magnet of the pair of magnets is coupled to the second nonmoving component; and

like poles of the first magnet and the second magnet face each other, wherein the magnetic force repels the sliding assembly towards the first nonmoving component.

3. The system of claim 2 , wherein the first magnet and the second magnet are configured such that, when the force in the second direction is below a threshold value, the sliding assembly and the second nonmoving component is separated by an air gap.

4. The system of claim 2 , wherein:

the first nonmoving component includes a slot;

a first part of the button is received in the slot; and

a second part of the button extends above the first nonmoving component through the slot,

wherein the sliding assembly, the first nonmoving component, and the second nonmoving component are configured such that, when a top surface of the button aligns with a top circumference of the slot, the sliding assembly and the second nonmoving component is separated by an air gap.

5. The system of claim 1 , further comprising a gear, wherein:

the sliding assembly further comprises a gear rack; and

the gear meshes with the gear rack of the sliding assembly and is rotatable by a movement of the gear rack of the sliding assembly.

6. The system of claim 5 , wherein:

the gear is coupled to a display assembly; and

rotating the gear by the movement of the gear rack of the sliding assembly causes a movement of the display assembly for the IPD adjustment.

7. The system of claim 1 , wherein:

the sliding assembly further comprises a friction pad;

the first nonmoving component comprises a surface with a plurality of teeth; and

the magnetic force presses the friction pad against the plurality of teeth to lock the sliding assembly to the first nonmoving component.

8. The system of claim 7 , wherein the friction pad comprises a material with an elasticity greater than a threshold value.

9. The system of claim 1 , wherein the pair of magnets comprises at least one of a permanent magnet or a electromagnet.

10. The system of claim 1 , wherein at least one of the pair of magnets has an elongated shape.

11. The system of claim 1 , wherein:

a second magnet of the pair of magnets is coupled to the first nonmoving component; and

opposite poles of the first magnet and the second magnet face each other, wherein the magnetic force attracts the sliding assembly to the first nonmoving component to lock the sliding assembly.

12. The system of claim 1 , wherein the sliding assembly is configured to be slidable in a direction different from the second direction after the button is pressed by the force in the second direction.

13. An optical device comprising:

one or more display assemblies; and

an interpupillary distance (IPD) adjustment system coupled to the one or more display assemblies, the IPD adjustment system comprising:

a first nonmoving component;

a sliding assembly comprising a button; and

a pair of magnets, wherein a first magnet of the pair of magnets is coupled to the sliding assembly;

wherein:

the pair of magnets are configured to exert a magnetic force, in a first direction, on the sliding assembly to press the sliding assembly against the first nonmoving component to lock the sliding assembly to the first nonmoving component; and

the sliding assembly is configured to, when the button of the sliding assembly is pushed by a force in a second direction opposite the first direction of the magnetic force, disengage with the first nonmoving component and become slidable with respect to the first nonmoving component.

14. The optical device of claim 13 , wherein:

the IPD adjustment system further comprises a second nonmoving component;

the sliding assembly is positioned between the first nonmoving component and the second nonmoving component;

a second magnet of the pair of magnets is coupled to the second nonmoving component; and

like poles of the first magnet and the second magnet face each other, wherein the magnetic force repels the sliding assembly towards the first nonmoving component.

15. The optical device of claim 14 , wherein the first magnet and the second magnet are configured such that, when the force in the second direction is below a threshold value, the sliding assembly and the second nonmoving component is separated by an air gap.

16. The optical device of claim 13 , wherein:

the sliding assembly further comprises a friction pad, the friction pad comprising a layer of an elastic material;

the first nonmoving component comprises a surface with a plurality of teeth; and

the magnetic force presses the friction pad against the plurality of teeth to lock the sliding assembly to the first nonmoving component.

17. The optical device of claim 13 , wherein:

a second magnet of the pair of magnets is coupled to the first nonmoving component; and

opposite poles of the first magnet and the second magnet face each other, wherein the magnetic force attracts the sliding assembly to the first nonmoving component to lock the sliding assembly.

18. The optical device of claim 13 , wherein:

the sliding assembly further comprises a gear rack;

the IPD adjustment system further comprises a gear, the gear coupled to the one or more display assemblies and meshed with the gear rack of the sliding assemble; and

the gear is rotatable by a movement of the gear rack of the sliding assembly to cause a movement of the one or more display assemblies for adjusting an IPD of the optical device.

19. A method for adjusting an interpupillary distance of an optical device, the method comprising:

pressing, by a pair of magnets, a sliding assembly against a first nonmoving component of an interpupillary distance (IPD) adjustment system to engage the sliding assembly with the first nonmoving component;

in response to pressing the sliding assembly by a user, disengaging the sliding assembly from the first nonmoving component; and

applying, by the pair of magnets, a magnetic repulsion force or a magnetic attraction force on the sliding assembly to prevent the sliding assembly being pressed from contacting a second nonmoving component.

20. The method of claim 19 , further comprising:

in response to sliding the sliding assembly relative to the first nonmoving component by the user, causing a rotation of a gear meshed with a gear rack on the sliding assembly, wherein the rotation of the gear causes a movement of a display assembly to adjust the IPD.