METHOD AND SYSTEM FOR DETERMINING AT LEAST ONE OPTICAL PROPERTY OF A VISUAL AID FOR A PERSON

Abstract

The present invention relates to a method for determining at least one optical property of a visual aid (e.g. eyeglasses) for a person, the method comprising the steps of: Observation of a test pattern (T) by the person through an tunable lens (20, 21) of a virtual reality (VR) and/or augmented reality (AR) headset (2) worn by the person, the tunable lens (20, 21) being positioned in front of an eye of the person, and adjusting at least one optical property of the tunable lens (20, 21) so that the person perceives the test pattern (T) as being sharp, or adjusting at least one optical property of the tunable lens (20, 21) until a sensor device (30, 31) detects accommodation of the eye of the person to the test pattern (T).

Claims

1. A method for determining an optimal value of an optical property for a visual aid for a person, the method comprising the steps of: a) providing a virtual reality and/or augmented reality headset comprising a tunable lens, b) Observation of a test pattern by the person through the tunable lens, and c) Adjusting an optical property of the tunable lens to an optimal value, wherein an image of the test pattern perceived by the person is changed by adjusting said optical property

2. The method according to claim 1, wherein step c) further comprises that the person adjusts the optical property to an optimal value, or a sensor device detects an optimal value of the optical property.

3. The method according to claim 1, wherein adjusting the optical property comprises changing a shape of a surface of the tunable lens by means of an actuator.

4. The method according to claim 1, wherein the optical property of the tunable lens is one of: sphere power, cylinder power, cylinder angle, prism power, prism angle.

5. The method according to claim1 , wherein the optical property of the tunable lens is sphere power, and step c) further comprises adjusting, as a further optical property, the cylinder angle of the tunable lens with the tunable lens comprising a predefined cylinder power until the optimal value of the cylinder angle is selected or detected.

6. The method according to claim 5, wherein step c) further comprises adjusting, as a further optical property, the cylinder power of the tunable lens until the optimal value of the cylinder power is selected or detected, wherein the cylinder angle is at the selected or detected optimal value.

7. The method according to claim 6, wherein step c) further comprises adjusting, as a further optical property, the prism angle of the tunable lens with the tunable lens comprising a predefined prism power until the optimal value of the prism angle is selected or detected.

8. The method according to claim 7, wherein step c) further comprises adjusting, as a further optical property, the prism power of the tunable lens with the prism angle being set to the optimal value of the prism angle.

9. The method according to claim 1, wherein the method further comprises the step of d) fabricating the visual aid, the visual aid comprising the optimal value of the respective optical property.

10. The method according to claim 1, the method further comprising the step of: d1) transmitting the optimal value of the respective optical property to a manufacturing device for optical elements, and d2) fabricating optical elements having the optimal value of the respective optical property, and particularly integrating the optical elements in a visual aid.

11. The method according to claim 9, wherein step d) comprises transmitting the optimal value of the respective optical property via a computer network.

12. A computer program comprising instructions which, when the computer program is executed on a computer cause the computer to conduct the method according to claim 1.

13. A system for determining at least one optical property of a visual aid for a person, the system comprising a VR and/or AR headset configured to be worn by the person, the VR and/or AR headset comprising a tunable lens configured to be positioned in front of an eye of the person when the VR and/or AR headset is worn by the person, wherein the tunable lens is adjustable to adjust at least one optical property of the tunable lens, and the system comprises an input device configured to be operated by the person to adjust the tunable lens and therewith the at least one optical property, and/or wherein the system comprises a sensor device, wherein the sensor device is configured to detect accommodation of said eye and to provide data based on the detected accommodation, wherein the system is configured to control adjusting of the tunable lens and therewith of the property based on said data.

14. The system according to claim 13, wherein the system comprises at least one display, the display configured to display the test pattern, wherein particularly the at least one display is comprised by the VR and/or AR headset.

15. The system according to claim 13, wherein the system comprises an actuator configured to change a shape of a surface of the tunable lens to adjust said at least one optical property.

16. The system according to claim 13, wherein said at least one optical property is one of: sphere power, cylinder power, cylinder angle, prism power, prism angle.

17. The system according to claim 13, wherein the system comprises a computer configured to transmit the at least one optical property to a remote server via a computer network.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Further features and advantages of the present inventions as well as embodiments of the present invention shall be described in the following with reference to the Figures, wherein

[0093] FIG. 1 shows an embodiment of a system according to the present invention for determining at least one optical property of an eyeglass for a person,

[0094] FIGS. 2A-2C show different examples of test patterns that can be used in the system and method according to the present invention,

[0095] FIG. 3 shows an embodiment of a lens shaping element of a tunable lens of the system,

[0096] FIG. 4 shows a process of changing optical properties of a tunable lens of the system by deforming a surface of the tunable lens using an actuator on points distributed along a periphery of the shaping element,

[0097] FIG. 5 shows a flow chart of an embodiment of the method according to the present invention,

[0098] FIG. 6 shows an example of an interface of the system allowing a user to select different options of the system and method regarding eye training.

[0099] FIG. 7 shows an embodiment of a display of the headset comprising light guides; and

[0100] FIG. 8 shows a further embodiment of a display of the headset comprising light guides.

DETAILED DESCRIPTION

[0101] FIG. 1 shows an embodiment of a system 1 according to the present invention for determining at least one optical property of a visual aid for a person (e.g. of an eyeglass for a person). As indicated in FIG. 1, the system 1 comprises a VR and/or AR headset 2 configured to be worn by the person, the VR and/or AR headset 2 comprising at least one tunable lens 20 configured to be positioned in front of an eye of the person when the VR and/or AR headset is worn by the person. Preferably, the headset 2 comprises a further tunable lens 21 for the other eye of the person. Particularly, the first tunable lens 20 may be arranged in front of the right eye of the person while the further or second lens 21 may be arranged in front of the left eye of the person.

[0102] Particularly, the respective tunable lens 20, 21 is adjustable to adjust at least one optical property of the respective tunable lens 20, 21 so that the person perceives a test pattern T observed through the respective tunable lens 20, 21 as being sharp. Particularly, test patterns T such as shown in FIGS. 2A to 2C can be used. Other suitable images may also be used. Particularly, the eyes can be examined separately, with the non-examined eye e.g. being closed, covered or otherwise separated from the optical path (e.g. by means of a shutter of the headset 2). Separate examination is particularly done for cylinder and sphere, while both eyes are considered in conjunction regarding prism.

[0103] Furthermore, the system 1 can comprise a sensor device 30, 31, the tunable lens(es) 20, 21 being configured to be adjusted to adjust a corresponding optical property of the respective lens 20, 21 until the sensor device 30, 31 detects accommodation of the respective eye of the person to the test pattern T observed through the respective tunable lens 20, 21. Particularly, the sensor device 30, 31 can comprise two cameras 30, 31, each camera 30, 31 being configured to monitor one eye of the person so that the left and right eye can be monitored separately. Particularly, accommodation of the respective eye can be detected by adjusting the corresponding optical property of the associated tunable lens 20, 21 in a continuous fashion (or in small successive increments) while observing the eye in questions of the person with the corresponding sensor device, particularly with the respective camera 30, 31, wherein the test pattern T is considered to be perceived as a sharp image by the person in case the lens of the eye under examination of the person stops changing its form at a certain value of the optical property. This can be inferred by automatically analyzing images of the lens of the eye acquired with the associated camera 30, 31. Such an analysis can be carried out by a computer 7 of the system 1 indicated in FIG. 1. The computer 7 can be any suitable computer such as a desktop computer, a laptop, a tablet or a smart phone (FIG. 1 depicts a selection of such computers although only one computer may be present in the system). It is also conceivable to have a computer 7 being integrated into the headset 2.

[0104] Furthermore, the headset 2 preferably comprises a display 80, 81 for each eye. In case of a VR headset 2, each display 80, 81 can be positioned in front of the respective eye when the VR headset 2 is worn for displaying information such as the test pattern T to the person. The respective tunable lens 20, 21 can then be arranged between the respective display 80, 81 and the respective eye. In case the headset 2 is an AR headset the respective display 80, 81 can be formed by the respective tunable lens 20, 21, i.e. by projecting information onto a surface of the respective tunable lens.

[0105] Particularly, as shown in FIGS. 7 and 8, in case of an AR headset 2, the respective display 80, 81 can be transparent. Particularly, for an AR headset 2 the display 80, 81 can comprise a transparent carrier 130 comprising light guides 13, each light guide 13 representing a pixel of the display 80, 81 via which augmented reality can be presented to the person (in case of VR, the respective display does not need to be transparent). Further, as shown in FIG. 7, the surface of the tunable lens 20, 21 facing away from the person can be formed by the carrier 130 comprising the light guides 13. Alternatively, said surface can be formed by a separate transparent plate 12. A lens shaping element 4 can be connected to the carrier 130 (FIG. 7) or to the plate 12 (FIG. 8) via a bellows 11 or another suitable structure. The lens shaping element 4 can be changed in its shape and/or position using an actuator 10. Particularly, the respective tunable lens 20, 21 and carrier 13 and particularly plate 12 can be held by a frame 15. Further, in AR, the test pattern T can also be displayed via a separate display of the computer 7 or can be a physical object observed by the person through the tunable lens(es) 20, 21 of the headset 2.

[0106] The system 1 can be used to conduct the method according to the present invention for determining at least one optical property of a visual aid (e.g. eyeglass) for a person (e.g. so as to automatically generate an eyeglass prescription for the person) comprising the steps of: [0107] a) Observation of the test pattern T by the person through a tunable lens 20, 21 of the headset 2 worn by the person, the tunable lens being 20, 21 positioned in front of an eye of the person, and [0108] b) Adjusting at least one optical property of the tunable lens 20, 21 so that the person perceives the test pattern as being sharp or [0109] Adjusting at least one optical property of the tunable lens 20, 21 until the sensor device 30, 31 detects accommodation of the eye of the person to the test pattern T.

[0110] Particularly, according to an embodiment, a complete set of optical properties, as can be required by an eyeglass prescription, can be inferred by means of the embodiment of the method shown in FIG. 5.

[0111] According to a first step 200, the test pattern T (such as e.g. shown in FIGS. 2A to 2C) is displayed by the VR and/or AR headset 2 or via an external display (e.g. of computer 7).

[0112] Thereafter, in step 201 the sphere power of the tunable lens 20 is tuned while it is checked 202 which value of the sphere power results in a best perception of the test pattern T. This optimal value of the sphere power is stored.

[0113] Thereafter, in step 203 the cylinder angle is tuned for a pre-defined small cylinder power while it is checked 204 which value of the cylinder angle results in a best perception of the test pattern T. This optimal value of the cylinder angle is stored.

[0114] Thereafter, in step 205 the cylinder power of the tunable lens 20 is tuned (with the cylinder angle assuming the optimal value) while it is checked 206 which value of the cylinder power results in a best perception of the test pattern T. This optimal value of the cylinder power is stored.

[0115] Thereafter, in step 207 the prism angle is tuned for a pre-defined small prism power (e.g. ±0.5) while it is checked 208 which value of the prism angle results in a best perception of the test pattern T. This optimal value of the prism angle is stored.

[0116] Thereafter, in step 209 the prism power of the tunable lens 20 is tuned (with the prism angle assuming the optical value) while it is checked 210 which value of the prism power results in a best perception of the test pattern T. This optimal value of the prism power is stored.

[0117] In step 211 the visual aid/eyeglass prescription can be derived from the stored optimal values of the optical properties.

[0118] Finally, in step 212 the visual aid (e.g. eyeglasses) can be fabricated according to the measured optimal values of the optical properties (e.g. from the derived eyeglass prescription). The optimal values (e.g. eyeglass prescription) may be send to a manufacturer M, a manufacturing device M, or an optician using computer 7 via a computer network N such as the internet (e.g. via e-mail or via an upload to a website of a manufacturer). The optimal values or prescription may also be printed out and taken to a manufacturer or optician for obtaining the visual aid (e.g. eyeglasses).

[0119] Furthermore, as indicated in FIG. 3, for adjusting the individual optical property of the respective tunable lens 21, here e.g. for the left eye of the person, so as to particularly give the lens 21 a desired sphere power, cylinder power, prism power, cylinder angle and prism angle), the respective tunable lens 21 can comprise a fluidic volume V, a flexible membrane 5 and a shaping element 4, wherein the membrane 5 delimits the fluidic volume V on one side, and wherein the shaping element 4 is attached to the membrane 5. Further, particularly, the shaping element 4 surrounds an optically active region of the membrane 5, wherein the shaping element 4 is arranged and configured to alter said at least one optical property of the tunable lens 20, 21 by being deflected by means of an actuator 10. This changes the shape of the surface of said active region of membrane 5 and therewith—depending on the deflection—the addressed optical properties (cf. also FIGS. 7 and 8)

[0120] Particularly, FIG. 3 shows the shaping element 4 of the respective tunable lens 20, 21 in a top view along the optical axis z of the respective tunable lens 20, 21 (cf. also FIG. 1). The shaping element 4 preferably comprises a non-circular ring shape, and an inner edge of the shaping element 4 defines a non-circular contour 41.

[0121] Particularly, the shaping element 4 extends within an imaginary circumcircle 40. The circumcircle 41 is a circle surrounding the shaping element 4, in particular the contour 40, within the main extension plane of the shaping element 4, wherein the circumcircle 41 has the smallest radius possible. Particularly, a lateral distance d between the circumcircle 41 and the contour 40 varies along a perimeter U of the shaping element 4. The lateral distance d is measured along the radius R the circumcircle 41. The shaping element 4 can further have a width w which varies along the perimeter U of the shaping element 4. The width w is measured in a direction along the radius R of the circumcircle 41.

[0122] Particularly, by way of deflection of the lens shaping element 4, one of, a selection of or all of the following optical properties: sphere power, cylinder power, prism power, cylinder angle, prism angle, can be adjusted.

[0123] In this regard, sphere power (abbreviated as SPH) indicates the amount of lens power, measured in diopters of focal length. The deflection of the membrane for sphere is equal in all meridians of the tunable lens. The shaping element 4 is configured to alter the lens power by a definable deformation of the membrane.

[0124] Cylinder power (abbreviated as CYL) indicates the lens power for astigmatism of the tunable lens 21. The membrane 5 has a non-spherical surface shape for generating cylinder power. In particular, for generating cylinder power the membrane has a shape so that along a first meridian the membrane has no added curvature, and along a second meridian the membrane 5 has the maximum added curvature, wherein the first meridian and the second meridian extend perpendicular with respect to each other. The shaping element is deformable to alter the curvature of the membrane 5 along the second meridian.

[0125] Cylinder angle describes the angle of the first meridian, which has no added curvature to correct astigmatism. In other words, the cylinder angle is the angle of the first lens meridian that is 90 degrees away from the second meridian, wherein the second meridian contains the cylinder power. The cylinder angle is defined with an angle from 1° to 180°. The shaping element 4 is deformable to alter the cylinder axis from 1° to 180° angle.

[0126] Furthermore, prism power is the amount of prismatic power of the tunable lens 21, measured in prism diopters (“p.d.” or a superscript triangle). Prism power is indicated in either metric or fractional English units (0.5 or ½, for example). Prism corresponds to a tilt of the membrane's 5 surface with respect to the optical axis z. Prism power defines the absolute of the angle by which the membrane's 5 surface is tilted. The shaping element 4 may be deformable to alter the prism power.

[0127] Prism angle is the direction of prismatic power of the tunable lens 21. The prism angle indicates the angle of the meridian around which the surface of the tunable lens is tilted with respect to the optical axis. The prism angle may extend along any meridian. The prism angle may be defined by an angle from 1° to 360°. The shaping element may be deformable to alter the prism angle from 1° to 360°.

[0128] Preferably, as indicated in the embodiment shown in FIG. 4, the tunable lens 21 comprises at least five actuation points, wherein at each actuation point there is a deflection point 42, a retention point 43 or both. Preferably, the tunable lens 21 comprises at least six actuation points, highly preferred at least eight actuation points. At the actuation points 42, 43 the deflection force 51 and/or the retention force 61 is transferred to the shaping element 4. In particular, at the actuation point 42, 43 the position of the shaping element 4 along the optical axis z is definable by the deflection force 51 and/or the retention force 61. For example, the actuation points 42, 43 are discrete points, wherein the shaping element 4 adapts its position along the optical axis z to the deflection of the neighboring actuation points 42, 43.

[0129] Particularly, at the retention points 43, the shaping element 4 can be connected to a mount 9 (such as a frame) via a rigid connection or via a spring, wherein an actuator 10 can be configured to exert a force at the respective actuation point along the optical axis z, wherein these forces can be independent from one another and can be individually adjusted. Particularly, the actuator can be an actuator system that comprise multiple actuators at each actuation point (e.g. based on shape memory alloys, piezo actuators etc.) to deflect the shaping element 4 at the respective actuation point by a predefined travel. in

[0130] Particularly, FIG. 4 shows the shaping element 4 in a specific tuned state in a schematic perspective view. The deflection points 42 and the retention points 43 are arranged along the perimeter U spaced apart from one another. Alternatively, at least some of the retention points 42 and some of the deflection points 41 may coincide. Furthermore, also shown is the deflection force 51 and the retention force 61 applied to the respective points 42, 43.

[0131] Finally, as indicated in FIG. 6, the system 1 according to the present invention may also be employed for eye training. Particularly, a user interface of computer 7 shown in FIG. 1 may be configured to display to the user a menu for selecting training options, such as “freely programmable exercises” 70, “Pre-programmed exercises” 71, and an “automatic progress tracking” 72 of the eye training performed by the person.