Shape changing optical device for ophthalmic testing devices
The present invention relates to An optical device ( 1 ), particularly for an ophthalmic device, comprising: a container ( 2 ) enclosing an internal space ( 3 ) of the container ( 2 ), wherein the internal space ( 3 ) is filled with a transparent liquid (L), and wherein the container ( 2 ) comprises a transparent bottom ( 21 ) and a transparent and elastically deformable membrane ( 22 ) opposing said bottom ( 21 ) such that the liquid (L) is arranged between the membrane ( 22 ) and the bottom ( 21 ), a deformable annular lens shaping element ( 4 ) connected to the membrane ( 22 ) so that a circumferential edge ( 41 ) of the lens shaping element ( 4 ) defines a central area ( 23 ) of the membrane ( 22 ) so that light can pass through the container ( 2 ) via the central area ( 23 ) and the bottom ( 21 ), wherein in a non-deformed state said edge ( 41 ) lies in a plane, and an adjustable spherical power and an adjustable cylindrical power, wherein for adapting the cylindrical power of the optical device ( 1 ), the lens shaping element ( 4 ) is configured to be bent out of said plane (P).
1. An optical device, comprising:
a container enclosing an internal space of the container, wherein the internal space is filled with a transparent liquid, and wherein the container comprises a transparent bottom and a transparent and elastically deformable membrane opposing said bottom such that the liquid is arranged between the membrane and the bottom,
a deformable annular lens shaping element connected to the membrane so that a circumferential edge of the deformable annular lens shaping element defines a central area of the membrane so that light can pass through the container via the central area and the bottom, wherein in a non-deformed state said edge lies in a plane, and
an adjustable spherical power and an adjustable cylindrical power, wherein for adapting the cylindrical power of the optical device, the deformable annular lens shaping element is configured to be bent out of said plane,
wherein the optical device comprises an actuator system that is configured to bend the deformable annular lens shaping element out of the plane in order to adjust the cylindrical power,
the actuator system is configured to displace a plurality of points of the deformable annular lens shaping element along an optical axis of the optical device to bend the deformable annular lens shaping element out of the plane in order to adjust the cylindrical power,
the actuator system comprises a plurality of actuators, wherein each actuator is configured to displace one of the points, and
each actuator comprises a mover that is movable towards the deformable annular lens shaping element along the optical axis of the optical device by means of the actuator, wherein each mover is configured to push against the associated point of the deformable annular lens shaping element via a point contact.
2. The optical device according to claim 1 , wherein for adapting the cylindrical power of the optical device, the deformable annular lens shaping element is configured to be bent out of said plane so that said edge of the deformable annular lens shaping element coincides with a cylindrical surface.
3. The optical device according to claim 1 , wherein the optical device comprises an adjustable prismatic power.
4. The optical device according to claim 1 , wherein the bottom forms an elastically deformable second membrane, and wherein the optical device comprises an annular second lens shaping element connected to the elastically deformable second membrane so that a circumferential edge of the annular second lens shaping element defines a central area of the elastically deformable second membrane.
5. The optical device according to claim 4 , wherein the annular second lens shaping element is a deformable annular second lens shaping element, wherein in a non-deformed state said edge of the deformable annular second lens shaping element defines a further plane, wherein for adapting the cylindrical power of the optical device, the deformable annular second lens shaping element is configured to be bent out of said further plane.
6. The optical device according to claim 4 , wherein the annular second lens shaping element is rigid.
7. The optical device according to claim 4 , wherein the transparent and elastically deformable membrane forms a shell having a nondimensional tension parameter k smaller than 5, wherein
the nondimensional tension parameter k is defined as
k
=
N
0
a
2
D
where No is the initial in plane radial tension load, a is the radius of the circular membrane and D is the bending stiffness.
8. The optical device according to claim 4 , wherein the actuator system is configured to tilt the lens shaping elements with respect to one another to adjust the prismatic power of the optical device.
9. The optical device according to claim 1 , wherein the optical device comprises a transparent optical element arranged between the membrane and the bottom such that the internal space is divided into two separate regions, and wherein the optical device comprises a flexible first lateral wall and a flexible second lateral wall, wherein the first lateral wall connects the lens shaping element to the optical element, and wherein the second lateral wall connects the optical element to the bottom.
10. The optical device according to claim 1 , wherein said points are distributed along the periphery of the deformable annular lens shaping element.
11. The optical device according to claim 1 , wherein said plurality of points (S1, . . . . S6) comprises at least five points or; six points.
12. The optical device according to claim 1 , wherein said points are equidistantly spaced along the periphery of the deformable annular lens shaping element.
13. The optical device according to claim 1 , wherein the actuator system is configured to displace the points along the optical axis of the optical device to adjust the spherical power of the optical device.
14. The optical device according to claim 1 , wherein the actuator system is configured to displace points of the deformable annular lens shaping element such that the lens shaping element is tilted with respect to the optical axis of the optical device to adjust the prismatic power of the optical device.
15. The optical device according to claim 1 , wherein each actuator comprises a mover that is movable towards or away from the deformable annular lens shaping element along the optical axis of the optical device by means of the actuator, wherein each mover is configured to push against or pull on an associated point of the deformable annular lens shaping element, and wherein each actuator comprises a spring element configured to exert a restoring force on the associated point of the deformable annular lens shaping element, wherein the deformable annular lens shaping element is coupled via a point contact to the respective mover and ene of: coupled via an opposing point contact to the respective spring element, or integrally formed with the respective spring element.
16. The optical device according to claim 15 , wherein the respective spring element is supported on the bottom of the container, or the respective spring element is supported on a lateral wall.
17. The optical device according to claim 15 , wherein the respective spring element is a coil spring or a leaf spring.
18. The optical device according to claim 15 , wherein the respective spring element is arranged in the internal space and immersed in the liquid, or the respective spring element is arranged outside the internal space of the container.