Apparatus and method for measuring visual acuity by using focus-tunable lens

A method of measuring a visual acuity (VA) by a focus-tunable lens, the method comprising:

• assigning a first optical power to a first lens region and a second optical power that is different from the first optical power to a second lens region, the first lens region and the second lens region being included on a lens surface of the focus-tunable lens;
• displaying a VA measuring image through a first output region and a second output region of an image combiner, which respectively correspond to the first lens region and the second lens region of the focus-tunable lens;
• receiving a first input of a user with respect to the VA measuring image;
• specifying one optical power of the first optical power and the second optical power based on the first input of the user;
• and
• determining a VA of the user based on the specified optical power,
• wherein the focus-tunable lens comprises a first liquid crystal lens comprising a first strip electrode array and divided into a plurality of first zones, and a second liquid crystal lens comprising a second strip electrode array and divided into a plurality of second zones,
• wherein the first strip electrode array comprises a plurality of first strip electrodes having a linear shape extending along a first direction, and the second strip electrode array comprises a plurality of second strip electrodes having a linear shape extending along a second direction perpendicular to the first direction,
• wherein the plurality of first strip electrodes and the plurality of second strip electrodes overlap each other orthogonally,
• wherein method further comprises:
• assigning the first optical power to the first lens region by setting a first voltage profile applied to at least one first strip electrode included in a first zone among the plurality of first zones corresponding to the first lens region and at least one second strip electrode included in a second zone among the plurality of second zones corresponding to the first lens region;
• and
• assigning the second optical power to the second lens region by setting a second voltage profile applied to at least one first strip electrode included in a first zone among the plurality of first zones corresponding to the second lens region and at least one second strip electrode included in a second zone among the plurality of second zones corresponding to the second lens region,
• wherein the assigning of the first optical power and the second optical power to the focus-tunable lens comprises applying a voltage to electrodes of the focus-tunable lens such that the first optical power has a first cylindrical lens optical power with the first direction, placed on the lens surface of the focus-tunable lens, as an axial direction, and the second optical power has a second cylindrical lens optical power with the second direction, placed on the lens surface of the focus-tunable lens and orthogonal to the first direction, as the axial direction based on measuring astigmatism of the user, and
• wherein the measuring of the VA of the user comprises determining an astigmatism direction of the user based on the axial direction of each of the first cylindrical lens optical power and the second cylindrical lens optical power.

A non-transitory computer-readable recording medium for executing a method of measuring a visual acuity (VA) by a focus-tunable lens on a computer, the method comprising:

• assigning a first optical power to a first lens region and a second optical power that is different from the first optical power to a second lens region, the first lens region and the second lens region being included on a lens surface of the focus-tunable lens;
• displaying a VA measuring image through a first output region and a second output region of an image combiner, which respectively correspond to the first lens region and the second lens region of the focus-tunable lens;
• receiving a first input of a user with respect to the VA measuring image;
• specifying one optical power of the first optical power and the second optical power based on the first input of the user;
• and
• determining a VA of the user based on the specified optical power,
• wherein the focus-tunable lens comprises a first liquid crystal lens comprising a first strip electrode array and divided into a plurality of first zones, and a second liquid crystal lens comprising a second strip electrode array and divided into a plurality of second zones,
• wherein the first strip electrode array comprises a plurality of first strip electrodes having a linear shape extending along a first direction, and the second strip electrode array comprises a plurality of second strip electrodes having a linear shape extending along a second direction perpendicular to the first direction,
• wherein the plurality of first strip electrodes and the plurality of second strip electrodes overlap each other orthogonally,
• wherein method further comprises:
• assigning the first optical power to the first lens region by setting a first voltage profile applied to at least one first strip electrode included in a first zone among the plurality of first zones corresponding to the first lens region and at least one second strip electrode included in a second zone among the plurality of second zones corresponding to the first lens region;
• and
• assigning the second optical power to the second lens region by setting a second voltage profile applied to at least one first strip electrode included in a first zone among the plurality of first zones corresponding to the second lens region and at least one second strip electrode included in a second zone among the plurality of second zones corresponding to the second lens region,
• wherein the assigning of the first optical power and the second optical power to the focus-tunable lens comprises applying a voltage to electrodes of the focus-tunable lens such that the first optical power has a first cylindrical lens optical power with the first direction, placed on the lens surface of the focus-tunable lens, as an axial direction, and the second optical power has a second cylindrical lens optical power with the second direction, placed on the lens surface of the focus-tunable lens and orthogonal to the first direction, as the axial direction based on measuring astigmatism of the user, and
• wherein the measuring of the VA of the user comprises determining an astigmatism direction of the user based on the axial direction of each of the first cylindrical lens optical power and the second cylindrical lens optical power.