Augmented reality device for adjusting focus region according to direction of user's view and operating method of the same

1. An augmented reality (AR) device comprising:

a plurality of first variable focus lenses and a plurality of second variable focus lenses, wherein each of the plurality of first variable focus lenses and each of the plurality of second variable focus lenses is an electrically tunable liquid crystal lens;

a plurality of waveguides, wherein each of the plurality of waveguides is disposed between the plurality of first variable focus lenses and the plurality of second variable focus lenses;

a plurality of eye trackers configured to obtain a left eye vector by tracking a direction of a left eye of a user of the AR device and a right eye vector by tracking a direction of a right eye of the user of the AR device;

a display module configured to project light of a virtual image toward the plurality of waveguides; and

one or more processors configured to:

determine a first focus adjustment region of a first left eye variable focus lens among the plurality of first variable focus lenses based on the left eye vector

determine a third focus adjustment region of a first right eye variable focus lens among the plurality of first variable focus lenses based on the right eye vector,

obtain a gaze point based on the left eye vector and the right eye vector,

adjust a refractive power of the first focus adjustment region and a refractive power of the third focus adjustment region based on the gaze point, and

based on the adjusted refractive power of the first focus adjustment region and the adjusted refractive power of the third focus adjustment region, adjust a refractive power of a second focus adjustment region of a second left eye variable focus lens among the plurality of second variable focus lenses and a refractive power of a fourth focus adjustment region of a second right eye variable focus lens among the plurality of second variable focus lenses.

2. The AR device of claim 1 , further comprising a memory storing a program comprising one or more instructions,

wherein the one or more processors are further configured to perform operations by executing the one or more instructions of the program stored in the memory.

3. The AR device of claim 1 , wherein when the user wears the AR device, the first left eye variable focus lens is disposed at a position spaced apart from the left eye of the user by a first distance, and the second left eye variable focus lens is disposed at a position spaced apart from the left eye of the user by a second distance,

wherein the second distance is greater than the first distance.

4. The AR device of claim 1 , wherein the one or more processors are further configured to control to apply a control voltage that generates a phase modulation profile relating to a position corresponding to the first focus adjustment region to the first left eye variable focus lens, and, based on the applied control voltage, adjust the refractive power of the first focus adjustment region by changing an angle at which liquid crystal molecules arranged at a position of the first focus adjustment region are arranged among liquid crystal molecules of the first left eye variable focus lens.

5. The AR device of claim 1 , further comprising a depth sensor configured to measure a depth value of a real world object disposed at the gaze point,

wherein the one or more processors are further configured to obtain the measured depth value of the real world object from the depth sensor and adjust the refractive power of the first focus adjustment region based on the measured depth value so as to adjust a focal length of a virtual object which is a partial region of the virtual image.

6. The AR device of claim 1 , wherein the one or more processors are further configured to adjust the refractive power of the second focus adjustment region to be the same as the refractive power of the first focus adjustment region in a direction opposite to a direction of the refractive power of the first focus adjustment region.

7. The AR device of claim 1 , wherein the one or more processors are further configured to determine the second focus adjustment region based on the left eye vector such that the first focus adjustment region and the second focus adjustment region are aligned in a direction of the left eye vector.

8. The AR device of claim 1 , wherein a size of the first focus adjustment region is determined based on a size of a virtual object that is a partial region of the virtual image output through a left eye waveguide.

9. The AR device of claim 1 , wherein a size of the second focus adjustment region is determined based on a size of a virtual object that is a partial region of the virtual image output through a left eye waveguide and a spaced distance between the first left eye variable focus lens and the second left eye variable focus lens.

10. The AR device of claim 1 , wherein a plurality of a first focus adjustment regions are provided on the first left eye variable focus lens, and

wherein the one or more processors are further configured to adjust refractive powers focus adjustment regions such that different vergences are formed according to the focus adjustment regions, the focus adjustment regions comprising at least one of the first focus adjustment region, the second focus adjustment region, the third focus adjustment region, and the fourth focus adjustment region.

11. An augmented reality (AR) device comprising:

a plurality of first variable focus lenses and a plurality of second variable focus lenses, wherein each of the plurality of first variable focus lenses and each of the plurality of second variable focus lenses is an electrically tunable liquid crystal lens;

a plurality of waveguides, wherein each of the plurality of waveguides is disposed between the plurality of first variable focus lenses and the plurality of second variable focus lenses;

a plurality of eye trackers configured to obtain a left eye vector by tracking a direction of a left eye of an user of the AR device and a right eye vector by tracking a direction of a right eye of the user of the AR device;

a display module configured to project light of a virtual image toward the plurality of waveguides; and

one or more processors configured to:

determine a first focus adjustment region of a first left eye variable focus lens among the plurality of first variable focus lenses based on the left eye vector obtained from the plurality of eye trackers and determine a third focus adjustment region of a first right eye variable focus lens among the plurality of first variable focus lenses based on the right eye vector,

obtain a gaze point based on the left eye vector and the right eye vector,

adjust a refractive power of the first focus adjustment region and a refractive power of the third focus adjustment region based on the gaze point,

to change a focal length of a real world object, adjust a refractive power of a second focus adjustment region of a second left eye variable focus lens among the plurality of second variable focus lenses and a refractive power of a fourth focus adjustment region of a second right eye variable focus lens among the plurality of second variable focus lenses, and

independently adjust the refractive power of the second focus adjustment region and the refractive power of the fourth focus adjustment region regardless of the refractive power of the first focus adjustment region and the refractive power of the third focus adjustment region.

12. An operating method of an augmented reality (AR) device, the operating method comprising:

obtaining a left eye vector by tracking a direction of a left eye using a first eye tracker and obtaining a right eye vector by tracking a direction of a right eye using a second eye tracker;

determining a first focus adjustment region of a first left eye variable focus lens based on the obtained left eye vector and determining a third focus adjustment region of a first right eye variable focus lens based on the obtained right eye vector;

obtaining a gaze point based on the left eye vector and the right eye vector,

adjusting a refractive power of the first focus adjustment region and a refractive power of the third focus adjustment region based on the gaze point;

based on the adjusted refractive power of the first focus adjustment region and the adjusted refractive power of the third focus adjustment region, adjusting a refractive power of a second focus adjustment region of a second left eye variable focus lens and a refractive power of a fourth focus adjustment region of a second right eye variable focus lens; and

projecting light of a virtual image toward a waveguide using a display module.

13. The operating method of claim 12 , wherein the adjusting the refractive power of the first focus adjustment region and the refractive power of the third focus adjustment region comprises:

applying a control voltage that generates a phase modulation profile relating to a position corresponding to the first focus adjustment region to the first left eye variable focus lens; and

based on the applied control voltage, adjusting the refractive power of the first focus adjustment region by changing an angle at which liquid crystal molecules arranged at a position of the first focus adjustment region are arranged among liquid crystal molecules of the first left eye variable focus lens.

14. The operating method of claim 12 , wherein the adjusting of the refractive power of the first focus adjustment region and the refractive power of the third focus adjustment region comprises:

measuring a depth value of a real world object disposed on the gaze point using a depth sensor; and

adjusting the refractive power of the first focus adjustment region based on the measured depth value so as to adjust a focal length of a virtual object which is a partial region of the virtual image.

15. The operating method of claim 12 , wherein the adjusting of the refractive power of the second focus adjustment region and the refractive power of the fourth focus adjustment region comprises: adjusting the refractive power of the second focus adjustment region such that the second focus adjustment region forms a vergence in a direction opposite to a direction of an adjusted vergence of the first focus adjustment region and adjusting the refractive power of the fourth focus adjustment region such that the fourth focus adjustment region forms a vergence in a direction opposite to a direction of an adjusted vergence of the third focus adjustment region.

16. The operating method of claim 15 , wherein the adjusting of the refractive power of the second focus adjustment region and the refractive power of the fourth focus adjustment region comprises:

adjusting the refractive power of the second focus adjustment region to be the same as adjusted refractive power of the first focus adjustment region in a direction opposite to a direction of the adjusted refractive power of the first focus adjustment region.

17. The operating method of claim 12 , further comprising determining the second focus adjustment region based on the left eye vector such that the first focus adjustment region and the second focus adjustment region are aligned in a direction of the left eye vector.

18. The operating method of claim 12 , wherein a size of the first focus adjustment region is determined based on a size of a virtual object that is a partial region of the virtual image output through the waveguide.

19. The operating method of claim 12 , wherein a size of the second focus adjustment region is determined based on a size of a virtual object that is a partial region of the virtual image output through the waveguide and a spaced distance between the first left eye variable focus lens and the second left eye variable focus lens.

20. A non-transitory computer readable recording medium storing a program for executing the operating method of claim 12 .