OPTICAL DEVICE AND TUNING UNIT FOR THE OPTICAL DEVICE

Abstract

An optical device is suggested, which comprises a container (2) enclosing an internal space (3), wherein the internal space (3) is filled with a transparent liquid (4), and wherein the container (2) comprises a transparent bottom (5) and a transparent and elastically deformable membrane (6) opposing said bottom (5) such that the liquid (4) is arranged between the membrane (6) and the bottom (5), a circumferential lens shaping element (10) connected to the membrane (6) so that a circumferential edge of the lens shaping element (10) defines a central area (8) of the membrane (6) so that light can pass through the container (2) via the central area (8) and the bottom (5), wherein the lens shaping element (10) is deformable and comprises a plurality of actuation points (11), wherein in each of the actuation points (11) the lens shaping element (10) is moveably mounted with respect to the transparent bottom (5) by a bearing means (12) and wherein at least one actuation point (11) is displaceable with respect to the transparent bottom (5).

Claims

1. An optical device (1), particularly an ophthalmic device, comprising: a container (2) enclosing an internal space (3), wherein the internal space (3) is filled with a transparent liquid (4), and wherein the container (2) comprises a transparent bottom (5) and a transparent and elastically deformable membrane (6) opposing said bottom (5) such that the liquid (4) is arranged between the membrane (6) and the bottom (5), a circumferential lens shaping element (10) connected to the membrane (6) so that a circumferential edge of the lens shaping element (10) defines a central area (8) of the membrane (6) so that light can pass through the container (2) via the central area (8) and the bottom (5), wherein the lens shaping element (10) is deformable and comprises a plurality of actuation points (11), wherein in each of the actuation points (11) the lens shaping element (10) is moveably mounted with respect to the transparent bottom (5) by a bearing means (12) and wherein at least one actuation point (11) is displaceable with respect to the transparent bottom (5).

2. An optical device (1) according to claim 1, wherein a deformation of the lens shaping element (10) and the membrane (6) in the central area (8) is adjustable by a relative displacement of at least one actuation point (11) with respect to at least another actuation point (11).

3. An optical device according to claim 1, comprising an optical axis (9), along which the light passes through the container (2) via the central area (8) and the transparent bottom (5), wherein the bearing means (12) each comprise a longitudinal axis (14), which is parallel to the optical axis (9), and wherein the bearing means (12) each are configured to adjustably guide the lens shaping element (10) along its respective longitudinal axis (14) in each of the actuation points (11).

4. An optical device (1) according to claim 3, wherein the bearing means (12) each comprise at least one screw element (13), wherein the screw element (13) is rotatably mounted with respect to the transparent bottom (5) and a rotation of the screw element (13) causes a displacement of the corresponding actuation point (11) along the longitudinal axis (14) of the respective bearing means (12).

5. An optical device (1) according to claim 4, wherein each screw element (13) is moveably mounted along the longitudinal axis (14) of the respective bearing means (12) and wherein each screw element (13) comprises a screw tip, which is designed to transmit a displacement motion of the screw element (13) to the corresponding actuation point (11) of the lens shaping element (10).

6. An optical device (1) according to claim 4, wherein each screw element (13) is non-moveable along the longitudinal axis (14) of its respective bearing means (12) and wherein each screw element (13) comprises a threaded radial surface, which is designed to transmit a displacement motion of the screw element (12) to the corresponding actuation point (11) of the lens shaping element (10), preferably via a spindle nut.

7. An optical device (1) according to claim 1, wherein the amount of actuation points (11) is at least five and the actuation points (11) are distributed along the perimeter of the lens shaping element (10) such that the relative displacement of at least one actuation point (11) with respect to the at least another actuation point (11) causes the central area (8) to be shaped according to a Zernike polynomial with a radial degree greater than zero, particularly comprising at least one of the modes Z.sub.2.sup.0, Z.sub.1.sup.−1, Z.sub.1.sup.1, Z.sub.2.sup.−2, Z.sub.2.sup.2.

8. Tuning unit (15) for an optical device according to claim 1, comprising at least one actuator (16), which is arranged to interact with the lens shaping element (10) in at least one of its actuation points (11) and/or its bearing means (12) and is configured to adjust the lens shaping element (10) and the membrane (6) in the central area (8) of the optical device (1) by a relative displacement of at least one actuation point (11) with respect to the transparent bottom and/or with respect to another actuation point (11).

9. Tuning unit (15) for an optical device (1) according to claim 4, comprising at least one actuator with a drive and a screwdriver (16), wherein the drive is configured to propel the screwdriver (16) in a rotary motion around a longitudinal axis and wherein the screwdriver (16) and at least one screw element (13) of the optical device (1) comprise corresponding mechanical interfaces so that the rotary motion of the screwdriver (16) is transmittable to the screw element (13) and wherein the displacement of an actuation point (11) is adjustable as a function of the rotary motion of the screwdriver (16).

10. Tuning unit (15) according to claim 9, comprising a controller unit (17), which is connected to the drive by means of signal transmission and wherein a dataset is available in the controller unit (17) or the optical device (1), which dataset represents a targeted tuning state of the screw element (13) and/or an information corresponding thereto and wherein the controller unit (17) is configured to control the drive to propel the screwdriver (16) in order to displace the screw element (13) from an initial tuning state to the targeted tuning state.

11. Tuning unit (15) according to claim 10, wherein the initial tuning state is represented by a rotation angle and/or a screwing height of the screw element (13) and/or a position of the lens shaping element (10) and the tuning unit (15) comprises a sensor means (18,19) to detect the initial tuning state and to transmit the initial state to the controller unit.

12. Tuning unit (15) according to claim 11, wherein the controller unit (17), the drive and the sensor means (18) at least partially define a feedback loop, wherein the sensor means (18) is configured to detect an actual tuning state of the screw element (13) and/or the position of lens shaping element (10) during a tuning process and to transmit an actual tuning state to the controller unit (17), which is designed to control the drive as a function of the initial tuning state and/or the actual tuning state and/or the targeted tuning state.

13. Tuning unit (15) according to claim 12, wherein the controller unit (17) and the drive are configured to set the initial tuning state of the screw element (13) by tuning the screw element (13) into an end position.

14. Tuning unit (15) according to claim 11, wherein the sensor means (18,19) is configured to determine an actual deformation of the central area (6) and/or a corresponding information thereto and the controller unit (17) is configured to transform the actual deformation of the central area (17) in at least one tuning state of one of the screw elements (13).

15. Tuning unit (15) according to claim 14, comprising at least a calibration pattern (20) and at least an image sensor (19) that are arrangeable in a transmissive and/or a reflective arrangement with respect to the optical device (1), and wherein the image sensor (19) is connected to the controller unit (17) by means of signal transmission and the controller unit (17) is configured to identify the actual deformation of the central area (8) as a function of image data.

16. Tuning unit (15) according to claim 9, with a plurality of actuators, each comprising a drive and a screwdriver (16), which are arranged according to the actuation points (11) of the lens shaping element (10), and which each are designed to interact with all actuation points (11) and/or bearing means (12) of the optical device (1) simultaneously.

17. Optical system comprising an optical device (1), particularly an ophthalmic device, with a container (2) enclosing an internal space (3), wherein the internal space (3) is filled with a transparent liquid (4), and wherein the container (2) comprises a transparent bottom (5) and a transparent and elastically deformable membrane (6) opposing said bottom (5) such that the liquid (4) is arranged between the membrane (6) and the bottom (5), a circumferential lens shaping element (10) connected to the membrane (6) so that a circumferential edge of the lens shaping element (10) defines a central area (8) of the membrane (6) so that light can pass through the container (2) via the central area (8) and the bottom (5), wherein the lens shaping element (10) is deformable and comprises a plurality of actuation points (11), wherein in each of the actuation points (11) the lens shaping element (10) is moveably mounted with respect to the transparent bottom (5) by a bearing means (12) and wherein at least one actuation point (11) is displaceable with respect to the transparent bottom (5), the optical system further comprising a tuning unit (15) with at least one actuator (16), which is arranged to interact with the lens shaping element (10) of the optical device (1) in at least one of its actuation points (11) and/or its bearing means (12) and is configured to adjust the lens shaping element (10) and the membrane (6) in the central area (8) of the optical device (1) by a relative displacement of at least one actuation point (11) with respect to the transparent bottom and/or with respect to another actuation point (11), wherein the optical device (1) and the tuning unit (15) are connectable to each other and in a connected state of the optical device (1) and the tuning unit (15), the tuning unit (15) is configured to change at least one optical property of the optical device (1), particularly by an interaction between the at least one actuator (16) with the at least one actuation point (11) and/or the bearing means (12).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG. 1 shows an embodiment of an optical device according to the invention in side view;

[0049] FIG. 2A shows the embodiment of the optical device according to the invention in top view;

[0050] FIG. 2B shows another embodiment of an optical device according to the invention in top view;

[0051] FIG. 3 shows the embodiment of the optical device with an embodiment of a tuning unit according to the invention in side view;

[0052] FIG. 4 shows another embodiment of an optical device according to the invention with another embodiment of a tuning unit according to the invention in side view;

[0053] FIG. 5 shows another embodiment of an optical device according to the invention with another embodiment of a tuning unit according to the invention in side view.

DETAILED DESCRIPTION

[0054] For better understanding, the reference numerals as used in FIGS. 1 to 5 are listed below.

TABLE-US-00001 1 Optical device 2 Container 3 Internal space 4 Transparent liquid 5 Transparent bottom 6 Membrane 7 Lateral wall 8 Central area 9 Optical axis 10 Lens shaping element 11 Actuation point 12 Bearing means 13 Screw element 14 Longitudinal axis 15 Tuning unit 16 Screwdriver 17 Controller unit 18 Sensor means 19 Image sensor 20 Calibration pattern

[0055] FIG. 1 shows an optical device 1 that may be used in a wearable virtual reality (VR-) device. When wearing such a VR-device, the optical device 1 may be arranged between a screen of the VR-device and a human eye and allows to correct an aberration of a human eye. Therefore, such a VR-device is particularly useful for people with a visual impairment that is usually corrected with glasses. Glasses are very uncomfortable to wear when using a known VR-device. By correcting said aberration, the optical device 1 provides an overall good user experience when wearing said VR-device since high quality VR-images can be experienced without wearing glasses or the like.

[0056] The optical device 1 as shown in FIG. 1 comprises a container 2 enclosing an internal space 3, wherein the internal space 3 is filled with a transparent liquid 4. The container 2 comprises a transparent bottom 5 and a transparent and elastically deformable membrane 6. The membrane 6 is arranged opposed to the transparent bottom 5 such that the liquid 4 is enclosed between the transparent bottom 5 and the membrane 6. A lateral wall 7 is configured to be a sealing member that encloses the internal space 3 between the membrane 6 and the transparent bottom 5.

[0057] The optical device 1 has an optical axis 9, along which the light passes through the container 2. The optical device 1 is designed in a way that a central area 8 of the membrane 6, which is enclosed by a lens shaping element 10, can be displaced with regard to the transparent bottom 5 or be deformed in order to change the optical properties of the optical device 1 and to influence the path of light that passes through the optical device 1.

[0058] In order to deform or to adjust the central area 8 relative to the transparent bottom, the circumferential lens shaping element 10 is arranged between the membrane 6 and the lateral wall 7. The lens shaping element 9 comprises a plurality of actuation points 11, that are evenly distributed along its perimeter. The actuation points 11 are configured in a way that they each are mechanically connected to a respective bearing element 12 of the optical device 1 and can each be displaced, if required, along a longitudinal axis 13 of a respective bearing element 12, which runs parallel to the optical axis 9 of the optical device 1.

[0059] According to the embodiment that is shown in FIG. 1, the bearing elements 12 each comprise a screw element 13 that is rotatably mounted with respect to the transparent bottom 5. A rotation of one of the screw elements 13 causes a displacement of the corresponding actuation point 11 along the longitudinal axis 14 of the bearing element 12. The screw elements 13 are mounted such that they are non-moveable along the longitudinal axis 14, however are rotatable around said longitudinal axis 14. A rotation of one screw element 13 causes a displacement of the corresponding actuation point 11 of the lens shaping element 10.

[0060] The lens shaping element 10 is designed to delimit the central area 8 of the membrane 6. A uniform displacement of all actuation points 11, the membrane 6 and thus also the central area 8 are uniformly adjusted in a piston movement with regard to the transparent bottom 5. A displacement of a single actuation point 11 is achieved by rotation of the corresponding screw element 13 and may lead to a deformation of the central area 8 as a function of the displacement of the actuation points 11.

[0061] The actuation points 11 are arranged in a way, that their displacement allows the central area 8 of the membrane 6 to be shaped according to a Zernike polynomial with a degree greater than zero. More particularly, the central area 8 of the membrane 6 may be shaped according to a Zernike polynomial with a mode Z.sub.2.sup.0. For this purpose, the actuation points 11 can be displaced evenly parallel to the optical axis 9 of the optical device 1, which affects the pressure in the transparent liquid 4. This leads to a convex shape of the central area 8 in order to defocus.

[0062] Alternatively, the central area 8 of the membrane 6 may be shaped according to a Zernike polynomial with a mode Z.sub.1.sup.−1. With regard to the coordinate system shown in FIG. 1, mode Z.sub.1.sup.−1 represents a tilt of the central area of the central area 8 around the y-axis. Furthermore, the central area 8 can be shaped according to a Zernike polynomial with a mode Z.sub.1.sup.1 that represents a tilt of the central area 8 around the x-axis. Furthermore, modes Z.sub.2.sup.−2 and Z.sub.2.sup.2 are adjustable, which correspond to oblique and vertical astigmatism respectively.

[0063] FIG. 2A and 2B show different possible embodiments of the optical device 1 according to FIG. 1.

[0064] According to a first possible embodiment, which can be seen in FIG. 2A, the optical device 1 has a substantially circular contour. The lens shaping element 10 is also circular, so that the central area 8 of the membrane 6 is limited accordingly.

[0065] According to a second possible embodiment, which can be seen in FIG. 2B, the optical device 1 has an oval contour. According to another embodiment, which is not shown here, the contour may also be polygonal, or freeformed such that the shape of the optical device 1 is adapted to the visual field of the human eye.

[0066] FIG. 3 shows a tuning unit 15 for the optical device 1 as shown in FIGS. 1 and 2A or 2B. The tuning unit 15 is configured as a smart screwdriver, which is arranged to interact with the screw elements 13 in order to displace at least one of the actuation points 11 and is configured to adjust a deformation of the lens shaping element 9 and the central area 8 of the membrane 6 by a relative displacement of at least one actuation point 11 with respect to the transparent bottom 5.

[0067] The tuning unit 15 comprises a drive (not shown) and a screwdriver 16, wherein the drive is configured to propel the screwdriver 16 in a rotary motion around a longitudinal axis and wherein the screwdriver 16 and at least one screw element 13 of the optical device 1 comprise corresponding mechanical interfaces so that the rotary motion of the screw driver 16 is transmittable to the screw element 13 and wherein the displacement of an actuation point 11 is adjustable as a function of the rotary motion of the screwdriver 16.

[0068] The tuning unit 15 is arranged to identify the screw element 13 it is attached to and at least the targeted tuning state for the screw element 13 in order define a desired shape of the central area 6.

[0069] The screw element 13 can be identified as a function of the spatial position of the screw element 13 relative to a reference point (not shown) of the tuning unit 15 or within the optical device 1. An information storage unit (not shown) can be configured to store information about the last set position of the screw elements 13 and can be read before a tuning process and used as the basis for a further tuning.

[0070] The screw driver 13 may comprise a read-write-unit (not shown) configured to read and rewrite information stored in the information storage unit of the optical device. More particularly, it is possible to write a number of turns or an angle of rotation or a comparable information in the storage unit after the completion of the screwdriving operation.

[0071] Alternatively, each screw element 13 may have an information storage unit (not shown), such as an RFID tag, in which an identification number or comparable information regarding the identity of the screw element 13 is stored. The screwdriver 16 may comprise an RFID read-write-unit configured to detect the ID number of the screw element 13 before the start of the screwdriving operation and to write a number of turns or an angle of rotation or comparable information on the RFID tag of the screw element 13 after the completion of the screwdriving operation. Additionally or alternatively, an initial tuning state of the screw element 13 can be set by the screw driver 16, by tuning the screw element 13 into an end position. Starting from this end position, the screw element 13 can be rotated until a targeted position is reached.

[0072] FIG. 4 shows another tuning unit 15 with a plurality of screwdrivers 16. The tuning unit 15 comprises a controller unit 17, which is connected to the drives (not shown) of the screwdrivers 16 by means of signal transmission and wherein a dataset is available in the controller unit 17. The dataset represents a targeted tuning state of the screw elements of the optical device 1 and wherein the controller unit 14 is configured to control the drives (not shown) to propel the screwdrivers 16 in order to set each of the screw elements 13 from an initial tuning state to the targeted tuning state. In this embodiment, the initial tuning state is represented by a rotation angle and a screwing height of the screwing element and the tuning unit 15 comprises a sensor means 18 to detect the initial tuning state and to transmit the initial state to the controller unit 17.

[0073] The sensor means 18 are configured as contactless sensors that allow to determine the rotation angle and a screwing height of one screwing element 13 each. Alternatively or additionally, the sensor means 18 can be configured to measure the height of the lens shaping element 10 or a section of its periphery. The height of the lens shaping element 10 or a section of its periphery can particularly be measured with respect to a reference point that is defined by a geometrical feature of the optical device 1, e.g. a housing or frame element (not shown).

[0074] The controller unit 14, the drive (not shown) and the sensor means 15 at least partially define a feedback loop, wherein the sensor means 15 are each configured to detect an actual tuning state of the screw element 13 during a tuning process and to transmit an actual tuning state to the controller unit 17, which is designed to control the drive (not shown) as a function of the initial tuning state, the actual tuning state and the targeted tuning state.

[0075] FIG. 5 shows another tuning unit 15 with a plurality of screwdrivers 16. The tuning unit 15 comprises an image sensor 19 and a calibration pattern 20. The optical device 1 is arranged between the image sensor 19 and the calibration pattern 20. The calibration pattern 20 can comprise a surface structure or printing, which can be detected by means of the image sensor 19 on the opposite side of the optical device 1. The sensor 19 may also be configured as a wavefront sensor, that allows to determine the shape of the central area 8 of the membrane 6.

[0076] Depending on the position of the central area 8 or its position relative to the transparent bottom 5, the surface structure or the printing of the calibration pattern 20 which is detected by the image sensor 19 is deviated with respect to the optical axis in accordance to the optical properties of the optical device 1. By measuring the calibration pattern 20 through the optical device 1 using the image sensor 19, image data is obtained that is compared with the nominal structure or printing of the calibration pattern 20. This can be done by using digital image processing methods. A mathematical model, which is created analytically or experimentally, allows to convert the deviations between the image data of the sensor means 19 and the nominal structure or printing of the calibration pattern 20 to at least one position of one actuation points 11 with respect to the transparent bottom 5 and/or relative to another actuation point 11. Accordingly, the mathematical model is used to calculate at least one targeted position of an actuation point 11 with respect to the transparent bottom 5 and/or relative to another actuation point 10 that needs to be set, in order to adjust the curvature of the central area 8 of membrane 6 in a desired manner.