Lens based on human visual system, video see-through apparatus employing the lens, and method of designing the lens
A lens includes at least one lens element configured to interface with a user's pupil along an optical-axis direction from a side of the user's pupil to a side of a display surface. The at least one lens element defines an aperture stop that is configured to be at least a portion of an area for facing the user's pupil. The aperture stop defines a plurality of sub-stop areas corresponding to a plurality of gaze directions within an entire viewing angle of the user with respect to the optical-axis direction. An orientation of the plurality of sub-stop areas are based on a human visual system.
1 . A lens comprising:
at least one lens element configured to interface with a user's pupil along an optical-axis direction from a side of the user's pupil to a side of a display surface,
wherein the at least one lens element includes an aperture stop that is configured to be at least a portion of an area for facing the user's pupil,
wherein the aperture stop includes a plurality of sub-stop areas corresponding to a plurality of gaze directions within an entire viewing angle of the user with respect to the optical-axis direction,
wherein each of the plurality of sub-stop areas corresponds to a first gaze direction of 0°, a second gaze direction of 10°, and a third gaze direction of 20°, respectively, by eye rotation, and
wherein an orientation of the plurality of sub-stop areas are based on a human visual system.
2 . The lens of claim 1 , wherein a radial width of each sub-stop area with respect to the optical-axis direction is based on a human pupil size.
3 . The lens of claim 1 , wherein each of the plurality of sub-stop areas is rotationally symmetrical about an optical axis in the optical-axis direction.
4 . The lens of claim 1 , wherein the plurality of sub-stop areas comprise a first sub-stop area and a second sub-stop area that partially overlap each other in a direction perpendicular to the optical-axis direction.
5 . The lens of claim 1 , wherein each of the plurality of sub-stop areas includes a sub-field range which is determined based on a change in visual acuity according to a human corneal eccentricity.
6 . The lens of claim 5 , wherein the sub-field range is allocated within an angular range of ±9° corresponding to a macular range in each of the plurality of gaze directions.
7 . The lens of claim 5 , wherein the sub-field range is nine degrees.
8 . The lens of claim 1 , wherein a central sub-stop area of the plurality of sub-stop areas corresponds to a front gaze direction to provide the entire viewing angle.
9 . The lens of claim 1 , wherein a size of an entire stop area of the stop surface is based on a total rotation angle (α) of a human eye.
10 . The lens of claim 1 ,
wherein the at least one lens element comprises a first lens element, a second lens element, and a third lens element, and
wherein the first lens element, the second lens element, and the third lens element are oriented sequentially along the optical-axis direction.
11 . The lens of claim 10 , wherein at least one surface of each of the first lens element, the second lens element, and the third lens element comprises a polarization-selective reflection layer.
12 . The lens according to claim 1 , wherein an aspherical shape of the lens is optimized to have modulation values that exceed a predetermined optical performance value in a preset range of spatial frequencies in a central area of the lens according to each of the plurality of gaze directions of each of the plurality of sub-stop areas.
13 . A head-mounted display (HMD) apparatus comprising:
an electronic display configured to display an image; and
a lens comprising at least one lens element configured to interface with a user's pupil along an optical-axis direction from a side of the user's pupil to a side of a display surface,
wherein the at least one lens element includes an aperture stop that is configured to be at least a portion of an area for facing the user's pupil,
wherein the aperture stop includes a plurality of sub-stop areas corresponding to a plurality of gaze directions with respect to the optical-axis direction,
wherein each of the plurality of sub-stop areas corresponds to a first gaze direction of 0°, a second gaze direction of 10°, and a third gaze direction of 20°, respectively, by eye rotation.
14 . A method of making a lens including at least one lens element configured to interface with a user's pupil along an optical-axis direction from a side of the user's pupil to a side of a display surface, the method comprising:
setting at least a portion of an area of the lens facing the user's pupil as an aperture stop;
dividing the aperture stop into a plurality of sub-stop areas corresponding to a plurality of gaze directions within an entire viewing angle of the user with respect to the optical-axis direction;
allocating a plurality of sub-field ranges to the plurality of sub-stop areas, respectively; and
optimizing each sub-stop area based on a corresponding gaze direction,
wherein each of the plurality of sub-stop areas corresponds to a first gaze direction of 0°, a second gaze direction of 10°, and a third gaze direction of 20°, respectively, by eye rotation.
15 . The method of claim 14 , wherein a radial width of each of the plurality of sub-stop areas with respect to the optical-axis direction is based on a human pupil size.
16 . The method of claim 14 , wherein each of the plurality of sub-stop areas is rotationally symmetrical about an optical axis in the optical-axis direction.
17 . The method of claim 14 , wherein the plurality of sub-stop areas comprise a first sub-stop area and a second sub-stop area that partially overlap each other in a direction perpendicular to the optical-axis direction.
18 . The method of claim 14 , wherein each of the plurality of sub-stop areas includes the sub-field range which is determined based on a change in visual acuity according to a human corneal eccentricity.
19 . The method of claim 18 , wherein the sub-field range is allocated within an angular range ±9° corresponding to a human macula range in each of the plurality of gaze directions.
20 . The method of claim 14 ,
wherein the at least one lens element comprises a first lens element, a second lens element, and a third lens element, and
wherein the first lens element, the second lens element, and the third lens element are oriented sequentially along the optical-axis direction.
21 . The method of claim 20 , wherein at least one surface of each of the first lens element, the second lens element, and the third lens element includes a polarization-selective reflection layer.