Method and apparatus for transporting an optical device, gripper for handling an optical device

Abstract

A method for transporting an optical device (350) is provided. The method includes holding the optical device (350) using a gripper (300) having a contactless suspension system (310), the optical device (350) having two major surfaces, such as a first major surface (352) and a second major surface (354). The holding of the optical device (350) includes providing the optical device (350) at an inclination angle (320) using the contactless suspension system (310). The method includes moving the gripper (300) from a first position (412) to a second position (424) to transport the optical device (350) in an inclined orientation. The movement from the first position (412) to the second position (424) includes an acceleration phase (410) and a deceleration phase (420). The method includes controlling the contactless suspension system (310) during at least a portion of the movement from the first position (412) to the second position (424) to adjust a first contactless force acting on the optical device (350). The first contactless force is set to a first value during at least a portion of the acceleration phase (410) and is set to a second value during at least a portion of the deceleration phase (420), the second value being different from the first value.

Description

METHOD AND APPARATUS FOR TRANSPORTING AN OPTICAL DEVICE, GRIPPER FOR HANDLING AN OPTICAL DEVICEFIELD

[0001] Embodiments described herein relate to apparatuses and methods for transporting optical devices. Embodiments described herein specifically relate to grippers for transporting optical devices, more specifically optical devices for augmented reality applications, such as waveguide combiners.BACKGROUND

[0002] Virtual reality is generally considered to be a computer-generated simulated environment in which a user has an apparent physical presence. A virtual reality experience can be generated in 3D and viewed with a head-mounted display (HMD) such as glasses or other wearable display devices that have near-eye display panels as lenses for displaying a virtual reality environment that replaces an actual environment.

[0003] Augmented reality, however, enables an experience in which a user can still see through the display lenses of the glasses or other HMD devices to view the surrounding environment, yet also see images of virtual objects that are generated for display and appear as part of the environment. Augmented reality can include any type of input, such as audio and haptic inputs, as well as virtual images, graphics, and video that enhances or augments the environment that the user experiences. As an emerging technology, augmented reality is accompanied by many challenges and design constraints.

[0004] In order to allow for a computer-generated virtual image to be combined with a real-world image of the environment so as to provide an augmented reality experience, optical combiners may be used. Such optical combiners may involve waveguides that include a substrate having a plurality of optical structures formed thereon. Since the optical structures are small (e.g. nano-sized), fragile structures that are easily damaged or contaminated, the handling of waveguides may be challenging. For example, a fast, automated processing of waveguides can be difficult, thus affecting the overall rate of productivity in the manufacture of display devices for augmented reality applications.

[0005] In light of the above, there is a need for improved systems and methods for handling optical devices such as waveguides for augmented reality applications.SUMMARY

[0006] According to an embodiment, a method for transporting an optical device is provided. The method includes holding the optical device using a gripper having a contactless suspension system, the optical device having two major surfaces. The holding includes providing the optical device at an inclination angle using the contactless suspension system. The method includes moving the gripper from a first position to a second position to transport the optical device in an inclined orientation, the movement from the first position to the second position including an acceleration phase and a deceleration phase. The method includes controlling the contactless suspension system during at least a portion of the movement from the first position to the second position to adjust a first contactless force acting on the optical device, wherein the first contactless force is set to a first value during at least a portion of the acceleration phase and is set to a second value during at least a portion of the deceleration phase, the second value being different from the first value.

[0007] According to a further embodiment, a method for transporting an optical device is provided. The method includes holding the optical device using a gripper having a contactless suspension system, wherein the holding comprises providing the optical device at an inclination angle using the contactless suspension system. The method includes moving the gripper from a first position to a second position to transport the optical device in an inclined orientation. The method includes measuring a position of the optical device while the gripper is moved from the first position to the second position. The method includes controlling the contactless suspension system during at least a portion of the movement of the gripper from the first position to the second position based on the measured position of the optical device.

[0008] According to a further embodiment, an apparatus for transporting an optical device is provided. The apparatus includes a gripper comprising a contactless suspension system arranged to provide the optical device at an inclination angle. The apparatus includes a controller connected to the contactless suspension system. The controller is configured to control the contactless suspension system during at least a portion of a movement of thegripper from a first position to a second position to adjust a first contactless force acting on the optical device. The first contactless force is set to a first value during at least a portion of an acceleration phase of the movement from the first position to the second position and is set to a second value during at least a portion of a deceleration phase of said movement, the second value being different from the first value.

[0009] According to a further embodiment, a gripper for handling an optical device is provided. The gripper includes a tilted or tiltable contactless suspension system. The gripper includes one or more side supports disposed adjacent to an optical device receiving area of the gripper. The gripper includes a position sensor facing the optical device receiving area.

[0010] Embodiments are also directed to apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the disclosure are also directed to methods for operating the described apparatus. The methods for operating the described apparatus include method aspects for carrying out every function of the apparatus.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following:FIGs. 1 (a)-(b) show an example of a waveguide;FIG. 2 shows a waveguide stack including several waveguides;FIG. 3 shows a gripper for handling an optical device according to embodiments described herein;FIG. 4 illustrates a method for transporting an optical device according to embodiments described herein;FIGs. 5-8 illustrate different states of operation of a gripper for handling an optical device according to embodiments described herein;FIG. 9 illustrates a method for transporting an optical device according to embodiments described herein; andFIGs. 10(a)-(b) show an example of a side support included in a gripper according to embodiments described herein.DETAILED DESCRIPTION

[0012] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0013] Embodiments described herein involve optical devices. A device may be considered an optical device if the optical properties of the device are relevant for the method or apparatus in which the device is used. At least a portion of an optical device can be made of a transparent material, such as glass or plastic. Some optical devices may be configured to change the properties, e.g. the propagation direction, of light. For example, an optical device may include optical structures for changing the propagation direction of light. Other optical devices may be unstructured and allow light to pass therethrough substantially unaltered. An optical device as described herein may be an optical device for use in augmented reality applications. An optical device can also be called an optical element. Examples of optical devices include waveguides and transparent cover elements, such as cover glasses, as described herein.

[0014] An optical device as described herein, such as a waveguide or a transparent cover element, can be a thin piece of material. An optical device can be a plate element, including a plate element having a flat surface or a plate element having a curved surface. An opticaldevice can have a first major surface and a second major surface opposite the first major surface. An optical device may be a substantially two-dimensional device, wherein a thickness of the optical device between the first major surface and the second major surface can be much smaller (e.g. 1 % or less) than a dimension, such as a length or width, of the first or second major surface. For example, the thickness of an optical device may be 1 mm or less, 500 pm or less, or 300 pm or less.

[0015] Figs. l(a)-(b) show an exemplary waveguide 10. As shown in Fig. 1(a), the waveguide 10 may include a substrate 110, which may be a thin piece of transparent material, such as glass or plastic. At least one grating structure, such as a grating structure 112 and a grating structure 114, may be disposed on the substrate 110. The waveguide 10 may include an input coupling region 102 defined by the grating structure 112. The waveguide 10 may include an output coupling region 104 defined by the grating structure 114. Light, in particular light corresponding to a virtual, computer-generated image, may be coupled into the waveguide 10 at the input coupling region 102. The light may propagate through the waveguide 10 until the light reaches the output coupling region 104. At the output coupling region 104, the light may exit the waveguide 10. Further, also at the output coupling region 104, light from the external, real -world surroundings may be transmitted through the waveguide 10 (as shown by the dashed line), allowing the user to see a combination of a virtual image and a real -world image. The waveguide 10 may be a waveguide combiner for providing an augmented reality experience to a user.

[0016] Fig. 1(b) shows a grating structure 120 of a waveguide 10 in more detail. The grating structure 120 may be the grating structure 112 or the grating structure 114 shown in Fig. 1(a), and may accordingly serve to provide an input coupling region or an output coupling region of the waveguide 10. The grating structure 120 may be formed on a major surface 12 of the substrate 110. The grating structure 120 may include a plurality of optical structures 122. The optical structures 122 may be configured to change a propagation direction of light incident on the grating structure 120. The optical structures 122 may have dimensions, e.g. width and / or height, that lie in the sub-micron and even nanometer range. The optical structures may be arranged adjacent to each other with a gap in between. As shown in Fig. 1(b), the optical structures 122 may be shaped, for example, as slanted fins.

[0017] The disclosure is not limited to the exemplary waveguide 10 shown in Figs. 1(a)- (b) and applies likewise to other waveguides. For example, a waveguide may have more than two grating structures (e.g. the waveguide may have one or more intermediate regions defined by further grating structures), the arrangement and shape of the optical structures 122 may be different from the example shown in Fig. 1(b), the waveguide may have grating structures disposed on both sides of the waveguide, and so on.

[0018] An optical device as described herein may be a waveguide. The waveguide may include a substrate. The waveguide may include a plurality of optical structures formed on the substrate. The optical structures may have sub-micro-dimensions, e.g. nano-sized dimensions. The plurality of optical structures may form one or more grating structures on the substrate. A waveguide can be a waveguide combiner. A waveguide combiner may be configured for combining a virtual computer-generated image with a real-world image of a surrounding environment. A waveguide may be an augmented reality waveguide combiner.

[0019] In an optical system, such as an augmented reality device, several waveguides may be stacked on top of each other to form a waveguide stack. For example, each waveguide in the waveguide stack may be configured for manipulating light in a respective wavelength range, which is beneficial for providing color images.

[0020] Fig. 2 shows an example of a waveguide stack 200. The waveguide stack 200 may include a cover glass 202a (bottom cover glass), a waveguide 10a, a waveguide 10b, a waveguide 10c and a cover glass 202b (top cover glass) stacked in this order. An adhesive 204a may be disposed between the cover glass 202a and the waveguide 10a. Adhesives 204b, 204c and 204d may be disposed between waveguides 10a and 10b, between waveguides 10b and 10c, and between waveguide 10c and cover glass 202b, respectively. Each of the waveguides lOa-c may be a waveguide as described herein, such as a waveguide 10 shown in Figs. l(a)-(b).

[0021] A cover glass, such as cover glasses 202a-b, may a protective glass. A cover glass may shield a surface of a waveguide adjacent to the cover glass, for example to prevent a grating formed on said surface from being contacted or contaminated. It may be the case that a cover glass has no optical structures, such as a grating.

[0022] An adhesive, such as adhesives 204a-d, may be configured to attach adjacent optical devices of a waveguide stack to each other. For example, adhesive 204a may be configured to attach cover glass 202a to waveguide 10a. An adhesive may be a pressure sensitive adhesive (PSA). An adhesive may be a pre-formed adhesive, such as a pre-formed PSA. An adhesive may have an elongated shape. For example, an adhesive may be an adhesive tape. An adhesive may function as a spacer providing a gap, particularly an air gap, between adjacent optical devices of the waveguide stack. Due to the adhesive, it may be the case that said adjacent optical devices do not contact each other.

[0023] The waveguide stack 200 shown in Fig. 2 includes a total of three waveguides. The disclosure is not limited thereto. A waveguide stack may include 1 or more, 2 or more, or 3 or more waveguides. For example, a waveguide stack may include a total of 2 waveguides stacked between a cover glass 202a and a cover glass 202b. In another example, a waveguide stack may include a single waveguide and a single cover glass.

[0024] Further, instead of cover glasses, transparent cover elements made of materials other than glass may be used in a waveguide stack. Throughout the present disclosure, a cover glass may be replaced by a transparent cover element.

[0025] A waveguide stack may be formed. Forming the waveguide stack may include placing a cover glass 202a on a support, placing an adhesive 204a on the cover glass 202a, placing a waveguide 10a on the adhesive 204a, placing an adhesive 204b on the waveguide 10a, and so on, in this order. Before placing a respective cover glass, waveguide, or adhesive on a preceding component in the (partial) stack, alignment operations may be performed to ensure that the components are correctly positioned within the waveguide stack. In order to provide a high-quality waveguide stack that is suitable for providing a sharp image, a high alignment precision of the different optical devices in a stack is beneficial.

[0026] According to embodiments described herein, an optical device, such as a waveguide, is handled, e.g. picked up, moved, transported, positioned, and the like, by a gripper without contacting the two major surfaces of the optical device. The optical structures on the major surfaces, such as grating structures of a waveguide, are not touched by the gripper during handling, ensuring that the optical structures are not damaged or contaminated. The optical device may be transported by side contact only, i.e., by contactingonly one or more side surfaces of the optical device. Further, embodiments described herein allow optical devices to be transported by a gripper with a high degree of control of the position of the optical device during transportation. Throughout the transportation movement, the position of the optical device relative to the gripper can be determined and controlled very precisely. This is beneficial in any application where the optical device shall be handled by the gripper with high precision, for example in a waveguide stack manufacturing process where multiple optical devices shall be stacked on top of each other with a high degree of alignment accuracy.

[0027] Fig. 3 shows a gripper 300 for handling an optical device 350 according to embodiments described herein.

[0028] A gripper 300 as described herein can be understood as a device configured for lifting an optical device 350 from a surface and transporting the optical device 350 from the surface to another position spaced apart from the surface. The gripper 300 may be positioned over the surface, may pick up the optical device 350 from the surface and may move the optical device 350 to a further surface. The gripper 300 holding the optical device 350 may place the optical device 350 on the further surface.

[0029] The optical device 350 may be a waveguide, a transparent cover element such as a cover glass, or another optical device. According to embodiments, the optical device 350 may be a waveguide comprising a substrate and a plurality of optical structures formed thereon. The plurality of structures may form a grating.

[0030] The optical device 350 may include a first major surface 352 and a second major surface 354 opposite the first major surface 352. The total area of the optical device 350 may be defined by the area of the first major surface 352 or the area of the second major surface 354. The first major surface 352 and the second major surface 354 may have substantially the same area.

[0031] The optical device 350 may have a side surface 356 and / or a side surface 358 between the first major surface 352 and the second major surface 354. A side surface, also called edge surface, of the optical device 350 may be a thin surface extending between the first major surface 352 and the second major surface 354. A side surface may have an areawhich is, for example, 10% or less of the area of the first major surface or the area of the second major surface. Where the optical device 350 is a waveguide, the side surface 356, and likewise the side surface 358, may be a side surface of a substrate of the waveguide extending between two major surfaces of the substrate. The side surfaces 356 and 358 may be two separate side surfaces (e.g. if the optical device 350 has a square shape) or may be two portions of one common side surface (e.g. if the optical device 350 has an elliptic or circular shape).

[0032] The gripper 300 may include a gripper body 302, or gripper head. The gripper body 302 may be disposed above the optical device 350 held by the gripper 300.

[0033] The gripper 300 may include a contactless suspension system 310. The contactless suspension system 310 may be mounted to, or supported by, the gripper body 302. The contactless suspension system 310, or contactless levitation system, may be configured for contactlessly suspending the optical device 350. The term “contactlessly suspending” can be understood in the sense that the optical device 350 is provided in a suspended, or levitated, state, wherein the contactless suspension system 310 does not include a mechanical support carrying the weight of the optical device 350 by means of contact between the mechanical support and the optical device 350. While the optical device 350 is provided in the suspended state by the contactless suspension system 310, it may be the case that there is no contact between the optical device 350 and the contactless suspension system 310. The contactless suspension system 310 may exert a contactless action on the optical device 350 that holds the optical device 350 at a predetermined distance from the contactless suspension system 310, for example a predetermined distance in a direction perpendicular to the first major surface 352 or second major surface 354 of the optical device 350. The contactless suspension system 310 may act on the optical device 350 from above the optical device 350. A contactless suspension system 310 may, for example, include an ultrasonic vibration generator, as described below.

[0034] The fact that the optical device 350 is contactlessly acted upon by the contactless suspension system 310 does not exclude portions of the optical device 350 from being contacted by other parts of the gripper 300. Yet, according to embodiments described herein, the gripper 300 is configured for handling the optical device 350 by side contact only, that is to say, by contacting only one or more side surfaces of the optical device 350, such as theside surface 356. It may be the case that there is no contact between any portion of the gripper 300 and the two major surfaces of the optical device 350.

[0035] The gripper 300 may be configured for providing the optical device 350 at an inclination angle 320, also called tilting angle, with respect to a horizontal plane 330. This may be achieved by arranging the contactless suspension system 310, and possibly the gripper body 302, in a tilted orientation, as shown in Fig. 3.

[0036] The inclination angle 320 may be an adjustable angle. The contactless suspension system 310 may be movable from a horizontal, or non-tilted, orientation to a tilted orientation at the inclination angle 320. The gripper 300 may include an actuator for adjusting the inclination angle 320 and / or for moving the gripper from a horizontal orientation to a tilted orientation. The actuator may be a motor, such as a servo motor.

[0037] Fig. 4 illustrates a method for transporting an optical device 350 according to embodiments described herein.

[0038] According to an embodiment, a method for transporting an optical device 350 is provided. The method includes holding the optical device 350 using a gripper 300 having a contactless suspension system 310, the optical device 350 having two major surfaces, such as a first major surface 352 and a second major surface 354. The holding of the optical device 350 includes providing the optical device 350 at an inclination angle 320 using the contactless suspension system 310. The method includes moving the gripper 300 from a first position 412 to a second position 424 to transport the optical device 350 in an inclined orientation. The movement from the first position 412 to the second position 424 includes an acceleration phase 410 and a deceleration phase 420. The method includes controlling the contactless suspension system 310 during at least a portion of the movement from the first position 412 to the second position 424 to adjust a first contactless force acting on the optical device 350. The first contactless force is set to a first value during at least a portion of the acceleration phase 410 and is set to a second value during at least a portion of the deceleration phase 420, the second value being different from the first value.

[0039] The left-hand side of Fig. 4 shows the gripper 300 holding the optical device 350 in an inclined orientation using the contactless suspension system 310. The gripper 300 is inthe first position 412. The first position 412 may be an initial position of a transportation movement performed by the gripper 300.

[0040] The gripper 300 holding the optical device 350 in an inclined orientation may transport the optical device 350 from the first position 412 to the second position 424. According to embodiments, during at least a portion of the movement from the first position 412 to the second position 424, the optical device 350 may be inclined by 5 degrees or more, particularly 10 degrees or more, or even 15 degrees or more, with respect to a horizontal plane.

[0041] The first position 412 and the second position 424 may be spaced apart from each other by a transportation distance 450. The movement from the first position 412 to the second position 424, also called transportation movement herein, may include a movement in a transportation direction 402. The transportation direction 402 may be an oriented direction from the first position 412 to the second position 424. The transportation direction 402 may be a substantially horizontal direction (allowing deviations from exact horizontality by, e.g., up to 15 degrees) The second position 424 may be spaced apart from the first position 412 with respect to the transportation direction 402.

[0042] The transportation movement of the gripper 300 from the first position 412 to the second position 424 need not be a movement in a single direction and can include movements in different directions. For example, the transportation movement can include an upward movement for picking up the optical device 350 at the first position 412, a substantially horizontal movement for transporting the optical device 350 in the transportation direction 402, a downward movement for putting the optical device 350 down at the second position 424, and the like. The transportation movement from the first position 412 to the second position 424 may include one or more straight portions and / or one or more curved portions.

[0043] The right-hand side of Fig. 4 shows the gripper 300 holding the optical device 350 in an inclined orientation using the contactless suspension system 310. The gripper 300 is in the second position 424. The second position 424 may be a final position of the transportation movement.

[0044] According to embodiments, the optical device 350 may be transported by the gripper 300 without contacting the two major surfaces of the optical device 350.

[0045] According to embodiments, during at least a portion of the movement of the gripper from the first position 412 to the second position 424, a slope of the optical device 350 defined from a trailing edge of the optical device 350 to a leading edge of the optical device 350 may be an upward slope. During said at least a portion, the leading edge may be disposed at a higher vertical position than the trailing edge.

[0046] The notions “trailing edge” and “leading edge” may be defined relative to the movement of the optical device 350 from the first position 412 to the second position 424, particularly relative to the transportation direction 402. The trailing edge may be behind the leading edge as the gripper 300 holding the optical device 350 moves from the first position 412 to the second position 424. In Fig. 4, the trailing edge is disposed at the side surface 356 and the leading edge is disposed at the side surface 358.

[0047] A slope of the optical device 350 can be understood as a slope of at least one of the first major surface 352 and the second major surface 354. The slope of the optical device 350 defined from the trailing edge to the leading edge can be understood as the slope of the optical device 350 when traversing the optical device 350 from the trailing edge to the leading edge (from the side surface 356 to the side surface 358 in Fig. 4). As can be seen in Fig. 4, when traversing the optical device 350 in this manner, the slope in question is an upward slope, since the leading edge (the side surface 358) is at an elevated position with respect to the trailing edge (the side surface 356).

[0048] Transporting the optical device in an inclined orientation wherein the slope is as defined above has the advantage that the position of the inclined optical device during transportation can be accurately controlled by adjusting the first contactless force provided by the contactless suspension system, as described in further detail below.

[0049] The movement of the gripper 300 from the first position 412 to the second position 424 includes an acceleration phase 410. An acceleration phase can be understood as a portion of the transportation movement during which the gripper 300 accelerates, particularly accelerates in the transportation direction 402. At an initial time, the gripper 300 may bestationary in the first position 412. The gripper 300 may move away from the first position 412 towards the second position 424, involving an acceleration of the gripper 300, e.g. an acceleration in the transportation direction 402. The gripper 300 may accelerate from the first position 412 to a first intermediate position 414. That is to say, the acceleration phase 410 may be defined from the first position 412 to the first intermediate position 414. The first intermediate position 414 may be a position between the first position 412 and the second position 424. The first intermediate position 414 may be spaced apart from the first position 412 by a distance, which may be a distance in the transportation direction 402.

[0050] During the acceleration phase 410, the optical device 350 held by the gripper 300 in an inclined orientation may be subject to an effective inertial force due to the inertia of the optical device 350 that is being accelerated. The effective inertial force is proportional to the applied acceleration, so that the effective inertial force can be relatively large even at the start of the transportation movement, e.g. if said movement is an impulsive movement.

[0051] During the acceleration phase 410, the optical device 350 held by the gripper 300 in an inclined orientation may be subject to an air pressure force pushing the optical device 350 in a direction opposite to the transportation movement of the gripper 300. The air pressure force may be caused by the effective air pressure acting on the inclined optical device 350, in particular on the inclined first major surface 352, caused by the movement of the optical device 350 in the transportation direction 402. The air pressure force may be a function of the speed of the gripper 300, and may in particular increase as the speed increases. Further, the air pressure force may depend on the inclination angle of the optical device 350, and may in particular be an increasing function of the inclination angle. In Fig. 4, the air pressure force may act towards the left. The air pressure force may push the optical device 350 towards the contactless suspension system 310. The air pressure force may increase during the acceleration phase, since the gripper 300 speeds up. According to embodiments, the contactless suspension system 310, and particularly the first contactless force, may be controlled during at least a portion of the acceleration phase 410 to compensate for the increasing air pressure force pushing the optical device 350 towards the contactless suspension system 310. The control of the first contactless force may be a real-time control. In some embodiments, the first contactless force may be a contactless repulsive force provided by a sonotrode, i.e. a force pushing the optical device 350 away from the contactlesssuspension system 310. During the acceleration phase 410, the contactless repulsive force may be controlled to be a relatively strong force to counteract the increasing air pressure force. By controlling the contactless repulsive force, the optical device 350 can be maintained at target distance with respect to the contactless suspension system 310 during the acceleration phase 410. An accurate control of the position of the optical device 350 during transportation can be provided.

[0052] The gripper 300 holding the optical device 350 in an inclined orientation may travel from the first intermediate position 414 to a second intermediate position 422, e.g. at a relatively constant speed. The second intermediate position 422 may be a position between the first intermediate position 414 and the second position 424. The second intermediate position 422 may be spaced apart from the second position 424 by a distance, which may be a distance in the transportation direction 402.

[0053] The movement of the gripper 300 from the first position 412 to the second position 424 includes a deceleration phase 420. A deceleration phase can be understood as a portion of the transportation movement during which the gripper 300 decelerates, particularly decelerates in the transportation direction 402. The deceleration phase 420 may be defined from the second intermediate position 422 to the second position 424. At the second position 424, the transportation movement may end. The gripper 300 may come to a standstill at the second position 424.

[0054] During the deceleration phase 420, an effective inertial force may act on the optical device 350 due to the deceleration of the optical device 350 and the inertia of the optical device 350.

[0055] During the deceleration phase 420, the air pressure force pushing the optical device 350 towards the contactless suspension system 310 may decrease, since the gripper slows down. According to embodiments, the contactless suspension system 310, and in particular the first contactless force, may be controlled during at least a portion of the deceleration phase 420 to compensate for the decreasing air pressure force. The control of the first contactless force may be a real-time control. For example, the first contactless force may be a contactless repulsive force provided by a sonotrode. During the deceleration phase 420, the contactless repulsive force may be controlled to be a relatively weak force, since the airpressure force is decreasing. By controlling the contactless repulsive force, the optical device 350 can be maintained at target distance with respect to the contactless suspension system 310 during the deceleration phase 420. An accurate control of the position of the optical device 350 during transportation can be provided.

[0056] According to embodiments, the contactless suspension system 310 may be controlled so that a distance between the optical device 350 and the contactless suspension system 310 remains within a target range during at least one of the acceleration phase 410 and the deceleration phase 420, particularly so that said distance is substantially constant during at least one of the acceleration phase 410 and the deceleration phase 420. Said distance may be controlled to be within a target range, and may particularly be controlled to be substantially constant, throughout substantially the entire transportation movement from the first position 412 to the second position 424.

[0057] Instead of a first contactless force that is repulsive, such as a repulsive force provided by a sonotrode included in the contactless suspension system 310, the first contactless force may be an attractive force, such as a suctioning force provided by a vacuum circuit included in the contactless suspension system 310. If the first contactless force is attractive, said force may be controlled to be relatively weak during the acceleration phase 410 (while, e.g., keeping the repulsive force provided by the sonotrode constant) to compensate for the increasing air pressure force. During the deceleration phase, the attractive contactless force may be controlled to be relatively strong to compensate for the slowdown of the gripper (again, while keeping the repulsive force provided by the sonotrode constant).

[0058] According to embodiments, the first contactless force provided by the contactless suspension system 310 may be a contactless repulsive force, the first value of the first contactless force being larger than the second value of the first contactless force. Alternatively, the first contactless force may be a contactless attractive force, the first value of the first contactless force being smaller than the second value of the first contactless force.

[0059] Fig. 5 shows a gripper 300 according to embodiments described herein. The gripper 300 may be part of an apparatus 500 for transporting an optical device, e.g. a pick-and-place apparatus. The apparatus 500 may include an arm 502 connected to the gripper 300. The apparatus 500 may include an actuator arrangement (not shown) including one or moreactuators, e.g. motors, for moving and positioning the gripper 300. Using the actuator arrangement, at least one of an upward movement, a downward movement, a horizontal movement and an angular movement of the gripper 300 may be provided.

[0060] According to embodiments, the first contactless force provided by the contactless suspension system 310 may be a contactless repulsive force. Alternatively, the first contactless force may be a contactless attractive force. The contactless suspension system 310 may include an ultrasonic vibration generator providing the contactless repulsive force. The contactless suspension system 310 may include a suction circuit providing the contactless attractive force.

[0061] The contactless suspension system 310 may include an ultrasonic vibration generator. The ultrasonic vibration generator may include a sonotrode 514, as shown in Fig.5. The sonotrode 514 may be configured for providing ultrasonic vibrations. The ultrasonic vibrations may result in a contactless repulsive force pushing the optical device away from the contactless suspension system 310, e.g. downward. The ultrasonic vibration generator may include a resonating element 512 (also called vibrating element), such as resonating plate, that may be connected to the sonotrode 514. The resonating element 512 may have a flat surface facing the optical device 350. The resonating element 512 may be configured for transmitting the ultrasonic vibrations created by the sonotrode 514 to an optical device receiving area of the gripper 300. A contactless repulsive force acting on the optical device 350, particularly pushing the optical device downward, may be provided across the area of the flat surface of the resonating element.

[0062] The contactless suspension system 310 may include a suction circuit 520. The suction circuit 520 may include or be a vacuum suction circuit or a suction circuit providing a Bernoulli grip. The suction circuit 520 may be provided, for example, in the resonating element 512. The suction circuit 520 may be configured for providing a suction force, or negative pressure, to attract the optical device 350 towards the contactless suspension system 310. The suction force may be a contactless attractive force, particularly an upward force, acting on the optical device 350. Due to the contactless repulsive force acting on the optical device 350 by means of the ultrasonic vibration generator, an air cushion is created between the ultrasonic vibration generator and the optical device 350, more particularly between theresonating element 512 and the optical device 350, preventing the optical device 350 that is attracted by the suctioning force from contacting the ultrasonic vibration generator.

[0063] By the combination of the (downward) contactless repulsive force provided by the ultrasonic vibration generator and the (upward) contactless attractive force provided by the suction circuit 520, a contactless suspension of the optical device 350 can be provided. The position of the suspended optical device 350 with respect to the contactless suspension system 310 (e.g. the distance between the optical device 350 and the resonating element 512) can be controlled by adjusting at least one of the contactless repulsive force provided by the ultrasonic vibration generator and the contactless attractive force provided by the suction circuit 520.

[0064] Figs. 5-8 and Figs. 9(a)-(g) illustrate different phases of operation of a gripper 300 that may be part of a method of transporting an optical device 350 according to embodiments described herein.

[0065] Fig. 5 and Fig. 9(a) show the gripper 300 in a first phase of operation, before the optical device 350 is held by the gripper 300. In the first phase of operation, it may be the case that the gripper 300 is not performing a transportation movement. The gripper 300 may be in the first position 412. The suction force provided by the suction circuit 520 may be activated to lift the optical device 350 towards the gripper 300, particularly towards the resonating element 512. The optical device 350 may be picked up from a first support surface 912, as shown in Fig. 9(a).

[0066] Fig. 6 shows the gripper 300 in a second phase of operation, which may occur after the first phase of operation. In the second phase of operation, it may be the case that the gripper 300 is not performing a transportation movement. The gripper 300 may be in the first position 412. The optical device 350 may be held by the gripper 300 in a suspended state. A contactless suspension of the optical device 350 may be provided by a combination of the contactless repulsive force provided by the ultrasonic vibration generator and the contactless attractive force provided by the suction circuit 520. The optical device 350 may be held in a horizontal, i.e. non-tilted, orientation. The second phase of operation is not shown in Fig. 9.

[0067] Fig. 7 and Fig. 9(b) show the gripper 300 in a third phase of operation, which may occur after the second phase of operation. In the third phase of operation, it may be the case that the gripper 300 is not performing a transportation movement. The gripper 300 may be in the first position 412. The optical device 350 may be held by the gripper 300 in a suspended state using the contactless suspension system 310. The optical device 350 may be provided at a first inclination angle 710. The optical device 350 may be provided in the first inclination angle 710 by rotating at least a portion of the contactless suspension system 310 (e.g. the resonating element 512) with respect to a rotation axis 590 of the gripper 300.

[0068] According to embodiments, and not limited to the third phase of operation, the optical device 350 may have a side surface 356 between the two major surfaces of the optical device 350. The holding of the optical device 350 may include supporting the side surface 356 by one or more side supports 550 of the gripper 300 while the optical device 350 is provided at an inclination angle, such as the inclination angle 320, the first inclination angle 710 or any other inclination angle described herein. According to embodiments, gravity acting on the optical device 350 that is being provided at the inclination angle causes the side surface 356 of the optical device 350 to be supported by the one or more side supports 550.

[0069] The gripper 300 may include one or more side supports 550. The one or more side supports 550 may be adjacent to an optical device receiving area of the gripper 300, i.e. adjacent to the position of the optical device 350 that is being held in a suspended state by the contactless suspension system 310. The one or more side supports 550 may be adjacent to a lowermost portion of the tilted optical device (e.g. the side surface 356).

[0070] The action of the contactless suspension system 310 on the optical device 350 allows the optical device 350 to be held in a suspended state at a predetermined distance between the optical device 350 and the contactless suspension system 310. Due to the tilted orientation of the optical device 350, gravity acting on the optical device 350 causes the optical device 350 to move downwards along the tilted plane of the optical device 350 (towards the bottom left in Fig. 7). The one or more side supports 550 may support the side surface 356 of the tilted optical device 350, so that a downward movement of the optical device 350 along said tilted plane due to the action of gravity is prevented. The one or more side supports 550 may be arranged for securing, or fixing, a position of the side surface 356of the optical device 350. Due to the action of gravity on the tilted optical device 350, the side surface 356 may abut against the one or more side supports 550.

[0071] It may be the case that the one or more side supports 550 contact neither the first major surface nor the second major surface of the optical device 350. Each side support of the one or more side supports 550 may be shaped to allow for a movement, particularly a sliding movement, of the optical device 350 along a portion of the side support, particularly in a direction substantially perpendicular to the first major surface or second major surface.

[0072] Embodiments described herein provide the advantage that the optical device 350 is held by the gripper 300 in a manner such that the major surfaces of the optical device 350 are not contacted by the gripper 300. Only one or more side surfaces, such as the side surface 356, may be contacted by the gripper 300. If one, or both, major surfaces of the optical device include fragile structures that are easily damaged or contaminated, such as the optical gratings of a waveguide, the gripper 300 according to embodiments described herein can handle such optical devices in a safe manner since the major surfaces are not touched.

[0073] Further, the tilted orientation of the optical device 350, in combination with the one or more side supports 550 that support the side surface 356, allow for an accurate determination and control of the position of the optical device 350 held by the gripper 300. While the optical device 350 is held by the gripper 300 in a tilted orientation, the side surface 356 abuts against the one or more side supports 550, so that the position of the optical device 350 with respect to the one or more side supports 550 may be stationary. Accordingly, the position of the optical device 350 held by the gripper 300 can be determined with high precision. The gripper can move the optical device into a target position with a high degree of control. In light thereof, a high-precision alignment of the optical device 350 can be achieved, which is beneficial, for example, for manufacturing waveguide stacks.

[0074] The first inclination angle 710 may be a relatively small angle. The first inclination angle 710 may be configured for allowing the side surface 356 of the tilted optical device to move into a position abutting against the one or more side supports 550. The first inclination angle 710 may be 10 degrees or less, or 5 degrees or less, with respect to a horizontal plane (said plane being indicated by a dashed horizontal line in Fig. 7). For example, the inclination angle 320 may be about 2-5 degrees.

[0075] Fig. 8 and Fig. 9(c) show the gripper 300 in a fourth phase of operation, which may occur after the third phase of operation. The fourth phase of operation may be part of the transportation movement from the first position 412 to the second position 424. The fourth phase of operation may be the acceleration phase.

[0076] According to embodiments, the optical device 350 may be provided at a first inclination angle 710 using the contactless suspension system 310 before performing the movement from the first position 412 to the second position 424. An orientation of the optical device 350 may be changed from the first inclination angle 710 to a second inclination angle 810. The second inclination angle 810 may be larger than the first inclination angle 710. The optical device 350 may be provided at the second inclination angle 810 during at least a portion of the movement from the first position 412 to the second position 424, such as during at least the acceleration phase 410.

[0077] The optical device 350 may be changed from the first inclination angle 710 to the second inclination angle 810 by rotating at least a portion of the contactless suspension system 310 (e.g. the resonating element 512) with respect to the rotation axis 590.

[0078] The second inclination angle 810 may be larger than the first inclination angle 710. The second inclination angle 810 may be 5 degrees or more, particularly 10 degrees or more, or even 15 degrees or more, with respect to a horizontal plane (said plane being indicated by a dashed horizontal line in Fig. 8). The optical device 350 may be provided at the second inclination angle 810 during at least a portion of the acceleration phase. At the start of the acceleration phase, the second inclination angle 810 may be set to a relatively small value, e.g. 5-10 degrees, to keep the effective inertial force acting on the optical device relatively small. As the gripper speeds up, the second inclination angle 810 may be increased to be relatively large in light of the effective air pressure force acting on the tilted optical device 350 during transportation of the optical device 350, particularly during the acceleration phase 410. By selecting the second inclination angle 810 to be in the aforementioned numerical ranges, a control of the position of the optical device 350 being transported by the gripper 300 can be facilitated and improved. Particularly, it can be ensured that the side surface 356 of the optical device 350, when said optical device is tilted at a second inclination angle 810 angle within said ranges, can remain in contact with the one or more side supports 550 during the transportation movement. An accurate determination and control of the position of theoptical device 350 during transportation from the first position 412 to the second position 424 can be provided.

[0079] During the fourth phase of operation, which may be the acceleration phase 410, the contactless suspension system 310 may be controlled to compensate for the increasing air pressure force pressing the optical device 350 towards the resonating element 512. The contactless repulsive force provided by the sonotrode 514 may be set to the first value during at least a portion of the acceleration phase 410, wherein the first value may be a relatively large value. Therein, the notion of “at least a portion” of the acceleration phase 410 may refer to a time period within the acceleration phase 410 or may even be a single moment in time during the acceleration phase 410. The contactless repulsive force, and more generally the first contactless force as described herein, may be adjusted during the acceleration phase to compensate for the fact that the air pressure force increases as the gripper accelerates. For example, the contactless repulsive force provided by the sonotrode 514 may be increased, e.g. gradually or stepwise, during the acceleration phase as the air pressure force increases. The first contactless force may be set to a plurality of values during the acceleration phase 410, e.g. a plurality of stepwise increasing values, where the first value as described herein is one of said values. The optical device 350 may be held at a substantially constant distance from the resonating element 512 throughout the acceleration phase 410.

[0080] Fig. 9(d) illustrates a fifth phase of operation of the gripper 300, which may occur after the fourth phase of operation. The fifth phase of operation may occur during the transportation movement from the first position 412 to the second position 424, particularly after the acceleration phase 410 and before the deceleration phase 420. The optical device 350 may be provided at a relatively small inclination angle of, for example, 5-10 degrees, so that the air pressure force acting on the optical device can be kept small. The gripper 300 may transport the optical device 350 at a substantially uniform speed. During the fifth phase of operation, which may be a phase of constant transportation speed, the contactless suspension system 310 may be controlled to compensate for the air pressure force pressing the optical device 350 against the resonating element 512. If the gripper 300 moves at a uniform speed, the air pressure force may be substantially constant. The contactless repulsive force provided by the sonotrode 514 may be set to a substantially constant value to ensurethat the optical device 350 remains at a substantially constant distance from the resonating element 512.

[0081] Fig. 9(e) illustrates a sixth phase of operation of the gripper 300, which may occur after the fifth phase of operation. The sixth phase of operation may be the deceleration phase 420. During at least a portion of the deceleration phase, the optical device 350 may be provided at a third inclination angle, which may be larger than the second inclination angle 810 provided in the acceleration phase. During at least a portion of the deceleration phase, it may be convenient to tilt the optical device to a third inclination angle of 45 degrees or more, particularly 50 degrees or more, or even 60 degrees or more. With such angles, the attractive force provided by the suction circuit may have a horizontal component sufficient to prevent the optical device from sliding away. During the sixth phase of operation, which may be the deceleration phase, the contactless suspension system 310 may be controlled to compensate for the decreasing air pressure force resulting from the slowdown of the gripper 300. The contactless repulsive force provided by the sonotrode 514 may be set to the second value during at least a portion of the deceleration phase 420, wherein the second value may be a relatively small value. Therein, the notion of “at least a portion” of the deceleration phase 420 may refer to a time period within the deceleration phase 420 or may even be a single moment in time during the deceleration phase 420. The contactless repulsive force, and more generally the first contactless force as described herein, may be adjusted during the deceleration phase 420 to compensate for the fact that the air pressure force decreases as the gripper slows down. For example, the contactless repulsive force provided by the sonotrode 514 may be decreased, e.g. gradually or stepwise, during the deceleration phase 420 as the air pressure force decreases. The first contactless force may be set to a plurality of values during the deceleration phase 420, e.g. a plurality of stepwise decreasing values, where the second value as described herein is one of said values. The optical device 350 may be held at a substantially constant distance from the resonating element 512 throughout the deceleration phase 420.

[0082] Fig. 9(f) illustrates a seventh phase of operation of the gripper 300, which may occur after the sixth phase of operation, particularly after the transportation movement from the first position 412 to the second position 424 has been completed. The operational state of the gripper 300 may be similar to the operational state shown in Fig. 6. In the seventhphase of operation, it may be the case that the gripper 300 is not performing a transportation movement. The gripper 300 may be in the second position 424. The optical device 350 may be held by the gripper 300 in a suspended state. The optical device 350 may be held in a horizontal, i.e. non-tilted, orientation. The optical device 350 may be changed from an inclination angle that was provided in the sixth phase to a horizontal orientation by rotating at least a portion of the contactless suspension system 310 (e.g. the resonating element 512) with respect to the rotation axis 590.

[0083] Fig. 9(g) illustrates an eight phase of operation of the gripper 300, which may occur after the seventh phase of operation. In the eighth phase of operation, it may be the case that the gripper 300 is not performing a transportation movement. The gripper 300 may be in the second position 424. The suction force provided by the suction circuit 520 may be decreased and / or the contactless repulsive force provided by the sonotrode 514 may be increased to discharge the optical device 350 from the gripper 300. The optical device 350 may be placed in a target position on a second support surface 924.

[0084] The sequence of operations shown in Figs. 5-8 and 9(a)-(g) is exemplary and the disclosure is not limited thereto. In particular, some of the phases of operation described above may be modified or omitted. In one example, the first phase of operation (Figs. 5 and 9(a)) may be modified in the sense that the gripper 300 may be provided in an inclined orientation already before picking up the optical device 350. The optical device 350 may be supported on an inclined surface upon being picked up by the gripper 300. In such an embodiment, the optical device 350 is held by the gripper 300 in an inclined orientation right away. Likewise, after the transportation movement has been completed and the gripper has arrived at the second position 424, the optical device 350 may be kept in an inclined orientation and placed on an inclined support surface, so that the rotation from the second inclination angle to a horizontal orientation (Figs. 9(f)-(g)) may be omitted. In another example, the transition from a horizontal orientation (Fig. 6) to the second inclination angle 810 (Fig. 8) may be performed by a continuous rotation of the gripper, so that the inclination of the optical device at the first inclination angle 710 as shown in Fig. 7 may not be discernable as a separate phase. In yet another example, it may be the case that a phase of constant transportation speed (Fig. 9(d)) is not present, in other words, that the transportation speed of the gripper is adjusted throughout substantially the entire transportation movement.

[0085] Referring again to Figs. 5-8, the gripper 300 may include a sensor 530, particularly a position sensor. The sensor 530 may face an optical device receiving area of the gripper 300. In other words, the sensor 530 may be arranged to face the optical device 350 that is being held by the gripper 300. The sensor 530 may face a major surface of the optical device 350, such as the second major surface 354. The sensor 530 may be configured to measure a position of the optical device 350 that is being held by the gripper 300. The sensor 530 may be configured to measure a position of the optical device 350 with respect to a direction perpendicular to a major surface of the optical device 350. Measuring a position of the optical device 350 may include, for example, measuring a distance from the sensor 530 to the optical device 350, particularly a distance from the sensor 530 to a major surface of the optical device. The sensor 530 may be configured for a contactless position measurement. The position of the optical device 350 may be measured by the sensor 530 without contact between the sensor 530 and the optical device 350. The sensor 530 may be configured for detecting a position of an optical device 350 that is transparent with respect to the visible light spectrum. For example, the sensor 530 may be a laser sensor. The wavelength range of the laser sensor may be a range suitable for detecting a position of an optical device 350 that is transparent with respect to the visible light spectrum.

[0086] Measurement data provided by the sensor 530 may be used for controlling the contactless suspension system 310 during transportation of the optical device 350 by the gripper 300. The control may be a closed-loop control. The sensor 530 may be connected to a controller of the apparatus 500. Position data regarding the position of the optical device 350 that is being held by the gripper 300 (e.g. data regarding a distance from the optical device to the sensor 530) may be transmitted from the sensor 530 to the controller. Based on the position data, the contactless suspension system 310, particularly the first contactless force provided by the contactless suspension system 310, may be controlled. Based on the position data, a position of the optical device 350 with respect to a direction perpendicular to a major surface of the optical device 350 may be controlled by controlling the first contactless force. Based on the position data, a distance from the optical device 350 to the contactless suspension system 310 may be controlled to be within a target range. Said distance may be controlled to be substantially constant. An improved control of the position of the suspended optical device 350 during transportation can be provided.

[0087] For example, during transportation of the optical device 350, particularly during the acceleration phase 410 and / or during the deceleration phase 420, one or more measurements may be performed by the sensor 530. Using data regarding the position of the optical device obtained from said one or more measurements, the contactless suspension system 310 may be controlled to maintain the optical device 350 at a target distance, or within a target distance range, from the contactless suspension system. Said target distance may be controlled to be substantially constant. During the acceleration phase 410, the measurement(s) performed by the sensor 530 may be used (by the controller) to determine that the optical device 350 is pushed towards the contactless suspension system 310, which may happen due to the air pressure force. The measurement(s) may be used to determine that the distance between the optical device 350 and the contactless suspension system 310 is decreasing. In response, the contactless repulsive force provided by the sonotrode 514 may be increased, particularly to compensate for the increasing air pressure force. The optical device 350 can be maintained at a constant distance from the contactless suspension system 310. During the deceleration phase 420, the measurement s) performed by the sensor 530 may be used to determine that the optical device 350 is moving away from the contactless suspension system 310, which may happen due to the decreasing air pressure force. The measurement s) may be used to determine that the distance between the optical device 350 and the contactless suspension system 310 is increasing. In response, the contactless repulsive force provided by the sonotrode 514 may be decreased, particularly to compensate for the decreasing air pressure force. The optical device 350 can be maintained at a constant distance from the contactless suspension system 310.

[0088] The sensor 530 may be part of the gripper 300. The sensor 530 may be isolated from the ultrasonic vibration generator, so that the ultrasonic vibrations do not cause a substantial vibration of the sensor 530. The precision of the position measurements performed by the sensor 530 can be improved.

[0089] According to embodiments, a position of the optical device 350 may be measured while the gripper 300 is moved from the first position 412 to the second position 424. The first contactless force may be controlled based on the measured position of the optical device 350. The position of the optical device 350 may be measured using a sensor 530 that is part of the gripper 300.

[0090] In some embodiments, the sensor 530 may be omitted. The control of the contactless suspension system 310 may be an open-loop control. For example, the control may be based on a pre-determined speed profile of the gripper during the movement from the first position 412 to the second position 424. Based on the speed profile, the first contactless force provided by the contactless suspension system 310 may be adjusted during transportation to ensure that the optical device 350 is maintained at a target distance with respect to the contactless suspension system 310.

[0091] The closed-loop control provided by embodiments having the sensor 530 may be advantageous over an open-loop control without the sensor 530. In the closed-loop case, it is possible to react in real-time to the actual forces acting on the suspended optical device 350 based on the measurements performed by the sensor 530. An improved control can be provided.

[0092] Figs. 10(a)-(b) show an example of the one or more side supports 550. A side support 550 may include two contact portions 1052 that are spaced apart from each other. The contact portions 1052 are arranged to contact a side surface of the optical device, such as side surface 356. By virtue of the contact portions 1052, optical devices having different dimensions can be held by the gripper 300, as illustrated in Fig. 10(a) and Fig. 10(b). The gripper 300 is not limited to one specific shape of the optical device. A universal gripper 300 for handling optical devices with different dimensions is provided.

[0093] According to embodiments, the gripper 300 may be rotatable with respect to a vertical rotation axis. The gripper 300 may be rotatable about the vertical rotation axis, for example by an angle of 180 degrees. For example, the gripper 300 may be rotatable from a first rotational position to a second rotational position. The first rotational position may be the position of the gripper shown in Fig. 5, where the one or more side supports 550 are on the left side of the optical device 350. The second rotational position may be obtained by rotating over 180 degrees, so that the one or more side supports 550 are on the right side of the optical device 350. Such a rotation of the gripper 300 increases the flexibility of the gripper 300, and e.g. allows picking up an optical device 350 from support surfaces that may be inclined in different directions.

[0094] According to a further embodiment, a method for transporting an optical device is provided. The method includes holding the optical device using a gripper having a contactless suspension system, wherein the holding comprises providing the optical device at an inclination angle using the contactless suspension system. The method includes moving the gripper from a first position to a second position to transport the optical device in an inclined orientation. The method includes measuring a position of the optical device while the gripper is moved from the first position to the second position. The method includes controlling the contactless suspension system during at least a portion of the movement of the gripper from the first position to the second position based on the measured position of the optical device. The method may include any operation or combination of operations that is / are part of a method for transporting an optical device as described herein.

[0095] According to a further embodiment, an apparatus for transporting an optical device is provided. The apparatus includes a gripper comprising a contactless suspension system arranged to provide the optical device at an inclination angle. The apparatus includes a controller connected to the contactless suspension system. The controller is configured to control the contactless suspension system during at least a portion of a movement of the gripper from a first position to a second position to adjust a first contactless force acting on the optical device. The first contactless force is set to a first value during at least a portion of an acceleration phase of the movement from the first position to the second position and is set to a second value during at least a portion of a deceleration phase of said movement, the second value being different from the first value. The apparatus may be configured to perform any operation or combination of operations that is / are part of a method for transporting an optical device as described herein.

[0096] According to embodiments, the contactless suspension system includes at least one of an ultrasonic vibration generator and a suction circuit.

[0097] According to embodiments, the gripper may include a sensor for measuring a position of the optical device.

[0098] According to a further embodiment, a gripper for handling an optical device is provided. The gripper includes a tilted or tiltable contactless suspension system. The gripper includes one or more side supports disposed adjacent to an optical device receiving area ofthe gripper. The gripper includes a position sensor facing the optical device receiving area. The gripper may include any aspect or combination of aspects that is / are part of a gripper as described herein.

[0099] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

CLAIMS1. A method for transporting an optical device (350), comprising: holding the optical device using a gripper (300) having a contactless suspension system (310), the optical device having two major surfaces (352, 354), wherein the holding comprises providing the optical device at an inclination angle (320) using the contactless suspension system; moving the gripper from a first position ( 12) to a second position (424) to transport the optical device in an inclined orientation, the movement from the first position to the second position including an acceleration phase (410) and a deceleration phase (420); and controlling the contactless suspension system during at least a portion of the movement from the first position to the second position to adjust a first contactless force acting on the optical device, wherein the first contactless force is set to a first value during at least a portion of the acceleration phase and is set to a second value during at least a portion of the deceleration phase, the second value being different from the first value.

2. The method of claim 1, wherein the optical device is a waveguide (10, lOa-c) comprising a substrate (110) and a plurality of optical structures (122) formed thereon.

3. The method of claim 1 or 2, wherein the optical device is transported by the gripper without contacting the two major surfaces of the optical device.

4. The method of any of the preceding claims, wherein, during at least a portion of the movement of the gripper from the first position to the second position, a slope of the optical device defined from a trailing edge of the optical device to a leading edge of the optical device is an upward slope.

5. The method of any of the preceding claims, wherein: the first contactless force is a contactless repulsive force, the first value of the first contactless force being larger than the second value of the first contactless force; or the first contactless force is a contactless attractive force, the first value of the first contactless force being smaller than the second value of the first contactless force.

6. The method of claim 5, wherein the contactless suspension system comprises at least one of: an ultrasonic vibration generator (514, 512) providing the contactless repulsive force; and a suction circuit (520) providing the contactless attractive force.

7. The method of any of the preceding claims, further comprising: measuring a position of the optical device while the gripper is moved from the first position to the second position, wherein the first contactless force is controlled based on the measured position of the optical device, particularly wherein the position of the optical device is measured using a sensor (530) that is part of the gripper.

8. The method of any of the preceding claims, wherein the optical device has a side surface (356) between the two major surfaces, wherein the holding of the optical device further comprises supporting the side surface by one or more side supports (550) of the gripper while the optical device is provided at the inclination angle.

9. The method of claim 8, wherein gravity acting on the optical device that is being provided at the inclination angle causes the side surface of the optical device to be supportedby the one or more side supports.

10. The method of any of the preceding claims, further comprising: providing the optical device at a first inclination angle (710) using the contactless suspension system before performing the movement from the first position to the second position; and changing an orientation of the optical device from the first inclination angle to a second inclination angle (810), wherein the second inclination angle is larger than the first inclination angle, wherein the optical device is provided at the second inclination angle during at least a portion of the movement from the first position to the second position.

11. A method for transporting an optical device (350), comprising: holding the optical device using a gripper (300) having a contactless suspension system (310), wherein the holding comprises providing the optical device at an inclination angle (320) using the contactless suspension system; moving the gripper from a first position (412) to a second position (424) to transport the optical device in an inclined orientation; measuring a position of the optical device while the gripper is moved from the first position to the second position; and controlling the contactless suspension system during at least a portion of the movement of the gripper from the first position to the second position based on the measured position of the optical device.

12. An apparatus (500) for transporting an optical device (350), comprising: a gripper (300) comprising a contactless suspension system (310) arranged to providethe optical device at an inclination angle (320); and a controller connected to the contactless suspension system, the controller being configured to control the contactless suspension system during at least a portion of a movement of the gripper from a first position (412) to a second position (424) to adjust a first contactless force acting on the optical device, wherein the first contactless force is set to a first value during at least a portion of an acceleration phase (410) of the movement from the first position to the second position and is set to a second value during at least a portion of a deceleration phase (420) of said movement, the second value being different from the first value.

13. The apparatus of claim 12, wherein the contactless suspension system comprises at least one of an ultrasonic vibration generator (512, 514); and a suction circuit (520).

14. The apparatus of claim 12 or 13, wherein the gripper comprises a sensor (530) for measuring a position of the optical device.

15. A gripper (300) for handling an optical device (350), comprising: a tilted or tiltable contactless suspension system (310); one or more side supports (550) disposed adjacent to an optical device receiving area of the gripper; and a position sensor (530) facing the optical device receiving area.

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