CN116615682A - Reducing effects in surface flattening variations caused by the formation of multiple focal points in a deformable lens - Google Patents
Reducing effects in surface flattening variations caused by the formation of multiple focal points in a deformable lens Download PDFInfo
- Publication number
- CN116615682A CN116615682A CN202280006848.8A CN202280006848A CN116615682A CN 116615682 A CN116615682 A CN 116615682A CN 202280006848 A CN202280006848 A CN 202280006848A CN 116615682 A CN116615682 A CN 116615682A
- Authority
- CN
- China
- Prior art keywords
- lenslet
- lenslets
- auxiliary
- optical
- optical system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
A (refocusable) lens system is accommodated, the lens system comprising a plurality of elastically deformable lenslets arranged in sequence along an optical axis, and the lens system having an optical power that is varied by varying the degree of flattening of the contact areas between the constituent lenslets in response to a variation in the force axially applied to the lens by an external element that is connected to or forms part of the lens system housing and/or the lenslet support element. Methods for operating a lens system in a manner that reduces optical wavefront errors introduced by a refocusing process, thereby improving imaging characteristics of the lens system.
Description
Cross Reference to Related Applications
The present patent application claims priority and benefit from U.S. provisional patent application Ser. No. 63/140,195, filed on month 21 of 2021, and Ser. No. 63/196,327, filed on month 3 of 2021. The disclosure of each of these provisional applications is incorporated herein by reference.
Technical Field
The present invention relates to a refocusable lens system, and in particular to an elastically deformable multi-lens system configured to continuously change its effective focal length due to axial partial flattening (flattening) or flattening (applanation) of the surfaces of the constituent lenses (lenslets) of such a system. Such multi-lens systems may be used as imaging lenses and/or objectives in various applications of opto-mechanical systems.
Prior Art
Those skilled in the art will readily appreciate that a refocusable lens system is an operable imaging system that is configured to operate by changing its optical power as a result of forming and/or changing the flattened (flattened or even flat) contact surface area between the surfaces of the individual elastically deformable constituent lenslets (constituent lenslets) of the lens system. Examples of such refocusable lens systems are discussed (e.g., in U.S. Pat. Nos. 9,848,980;10,191,261;10,307,247; international patent application publications WO 2015/134058, WO 2016/022771; the disclosure of each of these patent documents describing the operation of such lens systems is incorporated by reference in its entirety).
At the same time, during at least a portion of the operational transition of such a lens system of the related art (i.e., during the refocusing process, e.g., from a shorter focal length to a longer focal length), such a lens system may operate while undesirably distorting the optical wavefront of light propagating through it (i.e., by introducing wavefront errors), which reduces the quality of the optical image that may otherwise be achieved. One way of illustrating the source of such wavefront errors is to consider the operational transition of a lens system such as a related art multi-lenslet (see U.S.9,848,980 or U.S.10,191,261) from a non-flattened state (or less flattened state) to a fully flattened state (or a state in which the lenslets are flattened to a higher degree) of such a lens system during compression of at least one constituent lenslet relative to the other. Those skilled in the art will readily appreciate that in the non-flattened state, the reference lens system has a shorter focal length (when the mutually facing surfaces of adjacent lenslets of the lens system are unstressed and contact each other at a point on the optical axis). However, in a partially or even fully flattened state, the same lens system has a longer focal length (because substantially all of the contact surface area between the mutually facing surfaces of adjacent lenslets, or at least a significant portion of such surface area, is at least flattened or even flat compared to the surface profile of the same surface in a non-flattened state). For each constituent elastically deformable/mechanically pliable lens or lenslet of the overall lens system that participates in such an operational transition, the area of the flat portion of the corresponding lenslet surface is centered on the optical axis and increases as the flatness increases. At the same time, for each mutually flattened lenslet, such flat (inner axially centered) surface area is defined by the (outer) ring of lenslet surfaces that remain curved. It will be appreciated that the optical portion of the lens system, which operatively includes the flattened portion that constitutes the lenslet surface, generally defines one focal length (and thus optical power) of the system, while the optical portion of the lens system, which operatively includes the outer non-flattened portion that constitutes the lenslet surface, is characterized by different optical powers represented by different values of focal length. The operational transition from one level or degree of lens surface flattening to another level or degree of lens surface flattening actually results in the formation of multiple focal points (for the entire lens system) due to the simultaneous presence of flattened/flattened surface portions and curved surface portions in a given surface of a given constituent lenslet. In other words, during flattening of the constituent lenslets (or, similarly, during reduction of the flattening), there is more than one optical power characteristic in the same lens system that manifests as undesirable wavefront errors introduced by the lens system.
In practice, the optical wavefront distortion nature of the transition between the near and far focus states of the lens system comprehensibly deteriorates the image quality of the best focus (i.e. at the surface lying between the near and far focus polar values and chosen such that the rms spot size of the corresponding spot-diagram) reaches its minimum value), resulting in the refocusable lens system of the related art being diffraction limited substantially only at the extreme values of the given operational transition, where the surfaces making up the lenslets are either not flattened at all or flattened at all. A solution to this operational disadvantage is needed.
SUMMARY
Embodiments of the present invention provide a method for operating an optical system having an optical axis. The method includes the step of transmitting light incident on a front surface of an optical system having a first optical power through two surfaces of a first lenslet and a second lenslet of the composition of the optical system, the two surfaces being coaxial with an optical axis and in contact with each other at a first contact region (region) having a first contact surface area and centered on the optical axis. The method further comprises the steps of: the optical power of the optical system is changed from a first optical power to a second optical power by axially repositioning a first surface of the two surfaces along the optical axis to form a second contact zone between the first surface and the second surface of the two surfaces, the second contact zone having a substantially planar surface and having a second contact surface area different from the first contact surface area.
The method may additionally comprise substantially any combination of steps and/or conditions (a), (b), (c) and (d). Step (a) comprises the following steps: changing the secondary external force to compress the at least one secondary lenslet and a selected one of the composed first and second lenslets against each other along the optical axis or to relax an axial pressure exerted by one of the at least one secondary lenslet and the selected lenslet on the other of the two, thereby changing a flattened contact area between a surface of the at least one secondary lenslet and a surface of the selected lenslet. Alternative or additional step (b) is the following step: at least a portion of a circumferential edge of at least one constituent lenslet of the optical system is shifted along the optical axis while substantially not affecting an axial position of a center of such at least one constituent lenslet. Alternative or additional step/condition (c) is defined by: at least one of the step of changing the optical power of the optical system from the first optical power to the second optical power by repositioning the first surface of the two surfaces axially along the optical axis, and the step of changing the auxiliary external force (i.e., step (a)) includes changing the degree of flattening of the first aspheric surface and/or the second aspheric surface of the two mutually facing surfaces of the constituent lenslets of the optical system. Alternatively or additionally step (d) entails applying a radially directed load to the circumferential edge of at least one component lenslet of the optical system. In at least one implementation of the method, in particular in at least an implementation involving step (b), the process of displacing at least part of the circumferential edge of at least one constituent lenslet of the optical system along the optical axis may comprise a process of displacing at least part of the circumferential edge of at least one of the two immediately adjacent constituent lenslets of the optical system by transmitting an axial force applied to at least one of the two immediately adjacent constituent lenslets to (at least) a target of said circumferential edge using a haptic (haptic) of the two constituent lenslets connected to each other at their ends, or a process of displacing at least part of the circumferential edge of interest of at least one of the two immediately adjacent constituent lenslets of the optical system by applying an axially directed force to one of the first and second regions of the lenslet surface of interest. (where the first and second regions are located at two respective different radial positions of the surface in question.) at least in the case of this particular implementation of the method, the step of transmitting may comprise applying an axial force to a haptic having an annular region with an inner periphery (where the inner periphery defines and is attached to the circumferential edge).
In substantially any embodiment of the method, at least one of the steps of changing the auxiliary external force, displacing, changing the flattening of the first and/or second aspheric surfaces, and applying the radially directed load may be performed substantially simultaneously with the step of changing the optical power of the optical system from the first optical power to the second optical power and/or the process of changing the auxiliary external force. Alternatively or additionally, and in substantially each and any implementation of the method, each step of changing the optical power of the optical system from the first optical power to the second optical power, changing the auxiliary external force, shifting, changing the degree of flattening of the first and/or second aspheric surfaces, and applying the radially directed load may be performed reversibly. Alternatively or additionally, and in essentially each and any embodiment of the method, the step of displacing and/or varying the degree of flattening of the first aspheric surface and/or the second aspheric surface, and/or the step of applying a radially directed load, the respective steps may be performed on only a subset of the constituent lenslets of the optical system, rather than all and/or sequentially (i.e., on a pair-by-pair basis, with one pair being a pair of immediately adjacent constituent lenslets). In one particular case, a subset of lenslets may be defined as every other constituent lenslet that includes all constituent lenslets from the optical system. Alternatively or additionally, and in substantially each and any embodiment employing at least the method of step (a), the method may satisfy at least one of the following conditions: (i) Varying the degree of flattened contact area between the surface of the auxiliary lenslet and the surface of the selected lenslet depends on the degree of varying the auxiliary external force; and (ii) when the at least one auxiliary lenslet and the selected lenslet comprising the first lenslet and the second lenslet are unstressed, the at least one auxiliary lenslet is in contact with the selected lenslet at an axial point of the surface of the at least one auxiliary lenslet; and (iii) the step of varying the auxiliary external force comprises, when the plurality of auxiliary lenslets are not stressed, pressing the plurality of sequences of auxiliary lenslets in contact with each other at respective axial points against the selected lenslets, or relaxing the axial pressure exerted by one of the sequences and the selected lenslets on the other, thereby varying the plurality of flattened contact areas between the plurality of auxiliary lenslet surfaces.
Embodiments of the present invention also provide an optical system having an optical axis and including at least a first lenslet coaxial with the optical axis and having a first front surface and a first rear surface, and a second lenslet coaxially disposed with the first lenslet and having a second front surface and a second rear surface. The optical system (here, when the first lenslet and the second lenslet are unstressed, the first rear surface and the second front surface contact each other at an axial point.) may further comprise: a support structure comprising a first lenslet support element supporting at least a first lenslet and/or a second lenslet support element supporting a second lenslet; a first bearing and/or a second bearing movably connecting the first and/or second lenslet supporting elements with respect to each other and/or the supporting structure, thereby enabling translation of the first and/or second lenslet supporting elements substantially parallel to the optical axis and/or a change in stress applied to at least one of the respective supported first and second lenslets. The change in stress allows for flattening at least one of the first back surface and the second front surface and enables changing a flattened contact area between the first back surface and the second front surface centered on the optical axis by applying a first external force that advances or retracts at least one of the first lenslet supporting element and the second lenslet supporting element relative to the other and/or by applying a second external force to the first lenslet and/or the second lenslet that is vectorized substantially transverse to the optical axis. In addition, the optical system is configured to satisfy one or more of the following requirements (1) to (4). According to claim (1), the support structure further comprises an auxiliary lenslet support element supporting at least one auxiliary lenslet, the auxiliary lenslet being coaxial with the optical axis, and the auxiliary lenslet being in contact with the surface of the selected lenslet only at its axial point when the selected lenslets of the first and second lenslets of the auxiliary lenslet (1550) and optical system are unstressed. (here, the support structure may additionally include an auxiliary bearing that movably connects the auxiliary lenslet support element to the support structure and/or the first lenslet support element and/or the second lenslet support element, such that the auxiliary lenslet support element can be translated relative to the first lenslet support element and/or relative to the second lenslet support element in response to an auxiliary external force to effect a change in the flattened contact area between the surface of the at least one auxiliary lenslet and the surface of the selected lenslet by changing the auxiliary external force to compress the at least one auxiliary lenslet and the selected lenslet against each other along the optical axis, or to relax the axial pressure exerted by the at least one auxiliary lenslet and the selected lenslet on the other, furthermore, here, requirement (2) describes that at least one of the lenslet support elements present in the optical system has corresponding first and second contact regions that cooperate with the respective lenslets of the optical system at two respective different radial positions, and wherein the first and second contact regions are mechanically coupled to each other to transfer a force applied to at least one of the first and second contact regions to the respective lenslet to reversibly displace at least a portion of the circumferential edge of the respective lenslet along the optical axis, while not substantially affecting the axial position of the center of the corresponding lenslet. Claim (3) describes that two immediately adjacent lenslets of the optical system that make up the lenslet comprise respective haptics or finger-like structures extending radially from the circumferential regions of the two immediately adjacent lenslets, the respective haptics being sized to contact each other at their respective ends to transmit an axial force applied to at least one of the two immediately adjacent lenslets to at least a portion of the circumferential edge of the at least one of the two immediately adjacent lenslets to reversibly displace at least said portion along the optical axis while not substantially affecting the axial position of the center of the at least one of the two immediately adjacent lenslets. According to claim (4), at least one of the surfaces of the two immediately adjacent lenslets facing and contacting each other may comprise, in an unstressed state, an aspherical surface centered on the optical axis, and according to claim (5), the support structure may additionally comprise a radial loader device movably supported between an inner loader position and an outer loader position (the inner loader position and the outer loader position being defined at a first radial distance from the optical axis and a second radial distance from the optical axis, respectively, wherein the second radial distance is greater than the first radial distance). (here, a radial loader device is attached to a respective circumferential edge of at least one of the first, second and at least one auxiliary lenslet to apply radially directed forces to such circumferential edge.)
In at least one implementation of the optical system, the support structure may comprise a housing unit defining a hollow thereon, and respective portions of the first, second and at least one auxiliary lenslet may be disposed in the hollow, and respective portions of at least one of the first, second and auxiliary support elements may be sized to be reversibly displaced in the hollow along the optical axis. Alternatively or additionally, the respective portion of at least one of the first, second and auxiliary support elements may comprise a piston, or the surface of the hollow may be threaded, the threads being dimensioned to guide the respective portion of at least one of the first, second and auxiliary support elements.
Alternatively or additionally, and substantially in each implementation of the optical system that at least meets requirement (1), the at least one auxiliary lenslet may comprise a plurality of auxiliary lenslets, such that the optical system comprises a set of four or more constituent lenslets, each constituent lenslet contacting an immediately adjacent constituent lenslet at its axial point when the four or more constituent lenslets are unstressed. Alternatively or additionally, and at least in the case of an embodiment satisfying requirement (2), at least one of the first contact region and the second contact region may be configured as a part of a ring centered on the optical axis. Alternatively or additionally, and at least in the case of an embodiment meeting requirement (3), the haptic or finger-like structure may include respective annular portions, each annular portion having an inner periphery attached to the peripheral edges of respective lenslets of two immediately adjacent lenslets. Alternatively or additionally, and at least in the case of an embodiment meeting requirement (4), the aspheric surface is preferably an oblong aspheric surface.
Those skilled in the art will readily appreciate that embodiments that perform the above-described methods using substantially any embodiment of the optical system described above are also within the scope of the present invention and are so claimed.
Brief Description of Drawings
The invention will be more fully understood by reference to the following detailed description of specific embodiments, taken in conjunction with the accompanying drawings, not to scale, in which:
the invention will be more fully understood by reference to the following detailed description of specific embodiments, taken in conjunction with the accompanying drawings, not to scale, in which:
fig. 1A and 1B illustrate the profiles of two mechanically compliant component lenslets with spherical surfaces of one embodiment of a lens system, calculated using Abaqus FEA software for a stress-free (non-applanation) condition and for a substantially fully applanated condition, respectively. Only half of the lens system is shown with respect to the optical axis OA.
Fig. 2A, 2B, 2C and 2D provide graphs illustrating the variation of surface sag (surface sag) as a function of distance of a particular surface point from the optical axis OA for the surfaces of the lens system of fig. 1A, 1B for several flattening levels.
Fig. 3A includes a graph showing a comparison between changes in power introduced by the process of flattening the mutually facing surfaces of lenslets having a generally spherical surface, which are area-averaged, and changes observed with lenslets having non-spherical surfaces. Fig. 3B includes a graph showing a comparison between changes in wavefront error introduced by the same two pairs of lenslets following the same flattening process.
Fig. 4A, 4B, 4C and 4D include graphs showing changes in surface pit profile caused by axial compression of the lenslets in a pair of lenslets (resulting in changes in lenslet surface flattening) for a pair of lenslets having a spherical surface and for a pair of lenslets having an aspherical surface, corresponding to the graphs of fig. 3A, 3B.
Fig. 5A, 5B present graphs illustrating the variation of area-averaged optical power and wavefront error as a function of flattening of a given pair of mutually facing surfaces (surfaces II and III) of a component lenslet of embodiments of the lens systems of examples 1, 2, and 3, respectively.
Fig. 6 contains a comparison of changes in wavefront error corresponding to changes in area-averaged optical power in different embodiments of the lens systems discussed in this disclosure.
Fig. 7A, 7B schematically illustrate the principle of bending a lenslet of an embodiment of the lens system of the present invention using a supporting annular structure outside the lenslet (fig. 7A) and the stress distribution in the overall lenslet corresponding to such bending (fig. 7B). In this embodiment, the bending process of the lenslets is operationally substantially independent of the flattening process of the lenslets.
Fig. 8A, 8B schematically illustrate the principle of using a structural finger-like feature of a lenslet (fig. 8B) to bend the lenslets of an embodiment of the lens system as compared to a lenslet without such a structural feature. In this embodiment, the bending process is performed substantially simultaneously with and driven by the flattening process of the lenslets.
Fig. 9A, 9B, 9C and 9D schematically illustrate changes in surface depression profile corresponding to different axial compression increments/levels (and thus different flattening levels) of the lenslets having finger-like haptics and configured according to the embodiment of fig. 8B, as compared to changes in surface depression profile of the lenslets 110, 120 having no circumferential torque (torque) induced finger-like haptics and configured according to the embodiment of fig. 8A.
Fig. 10A, 10B provide graphs illustrating, for the embodiments of fig. 8A and 8B, respectively, the change in optical power of a pair of lenslets in contact with each other throughout the lens system and the wavefront error resulting from such a pair as a function of the degree of flattening of the mutually facing surfaces.
Fig. 11A, 11B, 11C, 11D, and 11E provide graphs of Optical Path Difference (OPD) fan-shape (fan) showing several degrees of applanation (represented by several degrees of compression of the lenslet pairs) for the lenslet pairs of examples 1, 2, and 5, each lenslet pair being modified to include finger-like haptics according to the principles illustrated in fig. 8B.
Fig. 12 schematically illustrates the principle of applying an external force (whether radial or anti-radial as shown) to the periphery of selected lenslets of a pair of lenslets of an optical system before, during, or after an incremental change in optical power of the pair of lenslets caused by applying an external force to at least one lenslet along the optical axis.
Fig. 13A, 13B, 13C, and 13D show graphs (maps) representing results of simulating specified axial compression of an example of a pair of lenslets with the Abaqus FEA software under different lateral loading conditions.
Fig. 14A, 14B and 14C provide a qualitative illustration of the process of refocusing the lenslet pairs 110, 120 (of the overall lens system comprising such pairs) by varying the degree of flattening of the surfaces II, III of the lenslets, accompanied by a transverse loading (with radial vector forces applied to the circumferential edges of the lenslets 120) to stretch the lenslets 120 in a direction transverse to the optical axis. 14A, 14B, 14C include a surface map on the left representing the lateral loading type of lenslets 120, and a map on the right representing the identified Zernike aberration terms as a function of the identified different degrees of compression of the pairs 110, 120 (corresponding to different degrees of flattening of surfaces II, III, and thus to different sizes of flat contact areas between the lenslets 110, 120 and different optical powers of the pairs 110, 120).
Fig. 15A and 15B are diagrams showing an embodiment of a zoom lens system including a plurality of elastically deformable constituent lenslets when no flattening is caused by the mutually facing inner surfaces of the system in side and front views.
Fig. 15C and 15D show side and front views of the embodiment of fig. 15A, 15B after the individual constituent lenslet arrays of the embodiment have been axially compressed (i.e., compressed along the optical axis).
Fig. 16A, 16B schematically illustrate an embodiment of a lens system comprising three constituent elastically deformable lenslets.
Generally, the sizes and relative proportions of the elements in the drawings may be set to be different from the actual sizes and relative proportions, in order to suitably facilitate the simplicity, clarity and understanding of the drawings. For the same reason, not all elements that appear in one figure are necessarily shown in another figure.
Detailed Description
In accordance with the inventive concept, the problem of undesired optical wavefront errors introduced by the flattening process of the constituent lenslets of a target mechanically compliant/elastically deformable lens system is solved by (re) configuring the lens system, for example, initially with a large number of constituent lenslets forming the target lens system (or, in the case concerned, increasing the number of constituent lenslets) to have a plurality of sequentially flattened lenslets (each optionally with reduced lens power and reduced distortion errors) that combine to produce the desired power variation of the overall lens system. The idea of the invention stems from the insight that as the thickness of the lenslets decreases, the absolute contribution to the wavefront error introduced by a given composition of lenslets of the overall lens system decreases. Alternatively or additionally, the lens system may be modified by adding at least aspheric terms to the surface profile of at least one of the mutually facing flattened surfaces comprising the lenslets and/or applying compression, torque and other stresses/forces, for example by applying bending moments (also called circumferential edge moments) to the edges of the flattened lenslets and/or by forces oriented along the diameter of the lenslets and thus transverse/perpendicular to the optical axis, whether tensile or compressive, preferably radial vector tensile forces, to minimize transition deformations and resulting wavefront errors/aberrations.
The applicability of the proposed solution to the related technical problem is explained below by considering several related iterations of a mechanically compliant multi-lenslet lens system, in each of which at least one of the two mutually facing surfaces of the immediately adjacent constituent lenslets is in contact with each other in a stationary or steady state (i.e. when the constituent lenslets are under no stress) and is subjected to a process that alters the degree of flattening or flattening of such surfaces. Typically, the process of varying the degree of applanation of a given surface is accomplished by the application of an external force that advances or retracts a structural support element configured to support and/or act on the lenslets with the given surface. Such advancement or retraction may be achieved, for example, through the use of a generic bearing arrangement (or simply bearing), which is generally understood to be relevant to machine elements that limit relative motion to only desired motion (and also preferably reduce friction between moving parts). See, for example, en.wikipedia.org/wiki/bearing_ (mechanical). The design of the bearing may for example provide free linear movement of the moving part or free rotation about a fixed axis; alternatively, it may resist movement by controlling the vector of the normal force exerted on the moving part. Bearings are generally categorized according to the type of operation, the allowed movement or the direction of the load (force) applied to the part. Examples of bearing arrangements that may be used for the purposes discussed in this disclosure include: a linear bearing; a sliding bearing in which one mechanical element, such as a cylinder or piston, is repositioned within another mechanical element, such as a hollow tubular element; a bearing utilizing a pair of threads; a hinge; means for using piezoelectric crystals (connectivity); and a hydraulic system; a servomotor, to name a few. In at least one instance, the bearings discussed herein operate to establish a degree of freedom for a given surface that is substantially parallel to the optical axis. In at least one particular embodiment, the process of varying the degree of applanation of a given lenslet is associated with and caused by a motion that is enabled and/or performed only along the direction of the optical axis.
In varying the degree of applanation, the flattened or flattened area of contact of the body lenslet surface with the immediately adjacent surface of the immediately adjacent lens is varied, thereby providing a change in optical power of the lens system and thus allowing refocusing of the lens system. Optionally, progressive flattening or flattening of at least one surface of the immediately adjacent lenslets is performed as the respective lenslets are axially compressed (using any suitable structural mechanism, such as those examples discussed in, for example, U.S.9,848,980 or U.S.10,191,261). Comparison between figures of merit representing wavefront errors caused by such iterations of the lens system convincingly demonstrates that the structural features introduced in one iteration do reduce the wavefront errors compared to the previous iteration, thereby improving the quality of the optical imaging. The progress of the discussion is as follows. For simplicity, the first to consider is the simplest configuration of a lens system comprising a plurality of compliant lenslets, each lenslet having a conventional, generally spherical surface. The next second lens system structure includes modifications to the profile of the surfaces of the two lenslets facing each other of this first design in that an aspheric term is added to the surface profile (in one particular case, to shape the axial portion of the surface into a prolate aspheric surface portion centered on the optical axis) to reduce the optical aberrations observed during flattening of such a system in response to externally applied forces, as compared to the optical aberrations of the first lens system. In the next step, the dual lenslet system of the first design is compared to a third structure comprising three lenslets, each lenslet having a simple spherical surface, to demonstrate that the optical aberrations introduced during flattening of the system with additional optical lens elements are reduced by the presence of such additional optical lens elements. The concept of using an increased number of constituent lenslets in the design to continue to reduce wavefront aberrations is further proposed, as a lens system comprising seven constituent lenslets will later be examined, indicating that the wavefront error introduced due to the flattening process of the seven lens system is smaller than the wavefront error introduced due to the flattening of the lens system of three lenslets. Based on these demonstrations, one of ordinary skill in the art will readily understand that essentially any increase in the number of constituent lenslets in the overall lens system, whether by adding 1 lenslet, 2 lenslets, 3 lenslets, or N >3 lenslets as compared to the initial first design, necessarily results in a problematic reduction in wavefront error, thereby providing practical support for generalization of the proposed method based on several demonstration examples.
When these different lens system configurations are considered flattened (by introducing axially directed compression of the constituent lenslets, e.g., in the manner discussed in U.S.10,191,261; for this reason, the actual implementation of flattening is not in any substantial detail herein), the average power and optical wavefront aberration over the entire surface area of the lenslets are simulated as the level of compression (i.e., degree of flattening) varies. As will be seen below, compression in the purely axial direction shows that adding an aspherical term to the spherical profile of a given design lenslet surface results in a reduction of the wavefront error peak associated with the process of refocusing the lens system by applanation. Similarly, in pure axial compression, the number of lenslets in the system is increased to M lenslets, M >2, producing the same effect.
Analysis method
In general, it is assumed that the lenslets are made of mechanically compliant (reversibly compressible, elastically deformable) material having a refractive index n=1.5168 and an isotropic elastic modulus e=1.0 kPa (these parameters are similar to those of silicone). The lens design in the unstressed (uncompressed, non-flattened) state was performed in Zemax OpticStudio optical analysis software. Most models were generated in Zemax OpticStudio and a few models were generated in the Abaqus FEA software according to the lens prescription. During the use of Finite Element Algorithm (FEA) to simulate axial compression (applanation) of a lens system, it is assumed that the first and last surfaces of the entire lens system are unchanged in profile by compression, while allowing the intermediate (interior of a given lens system) surfaces that make up the lenslets to be compliant and flattened/flattened. The simulated compression levels are defined as displacement drives at 0% (uncompressed, unstressed state), 10%, 30%, 60% and 100% (fully compressed/flattened) of the maximum sag between lenslet surfaces. The surface profiles at the different compression levels are then derived into data files and processed with Matlab as middleware to parse into corresponding mesh recess data files, which are then imported Zemax OpticStudio to generate spatially deformed (flattened ) lenslet surfaces ready for ray tracing simulation.
The mutual comparative configuration of the lens systems is designed to have a diffraction limit of about 10 diopters of optical power in the uncompressed (non-flattened, unstressed) state and about 1.25 diopters of diffraction limit when fully compressed. The lenslets were designed to have a mechanical diameter of 10.0mm, a center thickness of 2.5mm, and analyzed with an optically transparent aperture diameter of 9.0 mm. The optical performance of each system was analyzed at 550nm, taking into account the object distance of the on-axis object at infinity. The output wavefront aberration is recorded as Root Mean Square (RMS) wavefront error (WFE) Optical Path Difference (OPD) from the ideal/reference wavefront and calculated on an image plane selected to minimize the RMS-OPD-WFE. The total optical power is calculated by calculating the multiple ray trajectories over the transparent aperture area of a given lens system and calculating the average optical power over the transparent aperture area.
For the purposes of this disclosure and the appended claims, and unless explicitly defined otherwise, the terms "optical wavefront" and "wavefront" define a light field surface that contains a collection/locus (locus) of points where the light field has the same phase, as is commonly understood. In this sense, wavefront errors introduced in the operation of the lens system of the related art are those that result in substantial deviations of the optical wavefront from the substantially spherical surface. The term "surface" is used in its technical and scientific sense to refer to the boundary between two media or the boundary of a tangible element or a spatial boundary; it is understood to have a length and a width but no thickness, i.e. the skin of the subject (thickness zero). The term "optically conjugate" and related terms are understood to be defined by the principle of optical reversibility according to which light rays will propagate along an original path if the directions of propagation of the light are opposite. Thus, when referring to two surfaces, these terms are defined by two surfaces whose points are imaged one on the other with a given optical system. If an object is moved to the point occupied by its image, then a new image of the moved object will appear at the object's origin. The point across the optically conjugate surface is referred to and defined as the optically conjugate point.
Terms such as "radius of curvature", "sign of curvature" and related terms are identified with reference to the surface of the lenslet according to mathematical meanings accepted and commonly used in the relevant art. For example, the radius of curvature of a given curve at a point on the curve is typically defined as the radius of the circle closest to the curve at that point. The term curvature refers to the inverse of the radius of curvature. The definition of curvature may be extended to allow the curvature to take on positive or negative values (values with positive or negative signs). This is accomplished by selecting a unit normal vector along the curve, assigning a positive sign to the curvature of the curve if the curve is turned towards the selected normal, and a negative sign if the curve is away from the selected normal. For the purposes of this disclosure and the appended claims, the sign of a given curvature is defined in accordance with this convention. For definitions of these and other mathematical terms, the reader may further refer to standard reference text regarding mathematics, such as, for example, i.n. bronstein, k.a. semedev, reference on Mathematics for Engineers and University Students in 1981, science (or any other version). In one example, according to accepted practice in optics, if the vertex of a curved surface is to the left of its center of curvature, the radius of curvature and the curvature itself have a positive sign; if the vertex is to the right of the center of curvature, the radius of curvature and the curvature itself have a negative sign.
As known in the art, a surface of a lenslet is considered to be substantially spherical when the surface of the lenslet represents a portion of the surface of a sphere, while the term non-spherical surface or similar term generally defines and refers to a surface that is spatially offset from the spherical surface within identified boundaries. See, for example, en.
The terms "flattening", "flattening" and similar terms generally refer to a process or action with the result that the curvature of the surface of the object in question is reduced, i.e. the surface is flattened or flattened (resulting in a curvature of the surface that is at least reduced compared to the initial value of the curvature and/or in a particular case, the surface is substantially flat or planar). The term "congruent" when used with respect to the selected first and second elements designates that these elements overlap at substantially all points when superimposed.
The numbering of the structured surfaces-in describing the order of elements or components in an embodiment of the lens system of the invention or a subset of such systems, the following convention is generally followed herein unless otherwise indicated. In operation and/or upon installation, the order of the surfaces of the sequentially positioned structural elements of the lens assembly, as viewed in the direction of light incident on the lens system from the object, is ascending, wherein these surfaces are referred to as first surface (or surface 1, surface I), second surface (or surface 2, surface II), third surface (or surface 3, surface III), fourth surface (or surface 4, surface IV) and other surfaces (if present). Thus, in general, the surfaces of the structural elements (e.g., individual optical elements) of embodiments of the present invention are numbered starting from the surface corresponding to the front of the lens system and facing or even near the object, and ending at the surface corresponding to the rear of the assembly and near the image plane. Thus, the term "rear" refers to a location in space that is behind the other thing location and implies that one element or object is behind another element or object, as seen from the front of the lens assembly. Similarly, the term "in front of … …" refers to a forward position or location relative to a particular element as viewed from the front of the assembly. As will be appreciated by those skilled in the art, a lens, for example, is configured to receive light (light incident thereon from an ambient medium) through its front surface. As will be readily appreciated by those skilled in the art, when the order of surfaces and/or parameters of individual elements are changed as compared to the specifically discussed configuration, the change in optical characteristics and operation of the lens system may be dramatic and unpredictable and require separate consideration. In other words, any and/or hypothetical change in the orientation of a given lens system and/or its constituent elements (lenslets) relative to incident light may not provide equivalent or similar results in imaging an object as those for which such a given lens system has been configured.
The methods generally relate to the field of optics (such as, for example, objective lenses or lens systems for various imaging applications external to the human or animal body) and, in at least one example, represent non-medical and/or non-therapeutic methods to be performed external to the human or animal body or portion thereof-e.g., methods of adjusting the focal length of a lens system used to form an optical image of a given subject, methods of adjusting the focal length of an optical objective lens.
Example 1: two lenslet series with substantially spherical surfaces
A first contemplated solution consists of a lens system comprising two simple coaxial lenslets (see table 1) whose surfaces II and III facing each other in a stress-free (non-flattened) state are in contact with each other at an axial point (fig. 4A of u.s.10,191,261 provides a schematic reference for such an easy-to-visualize configuration).
Table 1:
| design 1: two lenslets | Radius of curvature: | surface profile: |
| lenslet 1-surface I: | 119.177mm | convex |
| Lenslet 1-surface II: | 785.827mm | convex |
| Lenslet 2-surface III: | 63.952mm | convex |
| Lenslet 2-surface IV: | 166.640mm | concave shape |
Starting from this initial configuration, in which the two constituent lenslets have only contact points on the axis and are not stressed, the lens system is considered to be compressed along the axis, so that progressive mutual flattening of surfaces II and III occurs (in the same technical manner as discussed in U.S.10,191,261), fig. 1A and 1B show the lens system profile for the following states simulated with FEA: an unflattened state (FIG. 1A; there is only a single point of contact P between two lenslets on optical axis OA 104); and a substantially fully compressed (flattened) state of surfaces II and III (fig. 1B), wherein surfaces II and III are considered to contact each other at substantially any radial point. Fig. 2A, 2B, 2C and 2D are graphs showing the variation of surface sag values as a function of separation of a specific surface point from the optical axis OA for several progressively increasing levels of applanation of the surface of such a lens system. Here, the degree of flattening corresponding to "increment 1" is smaller than that corresponding to "increment 2", and the degree of flattening corresponding to "increment 3" is larger than that corresponding to "increment 2". Table 2 summarizes the wavefront errors (RMS OPD WFE) introduced by embodiments of lens systems with different degrees of surface II, III applanation. The degree of applanation is expressed by the level of axial compression of the constituent lenslets, expressed as the percentage of sag between surfaces II and III removed by applanation. (increased% compression may be considered as an increase in area of surfaces II, II in contact with each other). Here, the wavefront errors in the substantially unstressed state of the lens system (0% compression/applanation), the substantially fully applanated state (100% area applanation of surfaces II, II) and several intermediate states are summarized. It can be observed that as the degree of applanation increases gradually, the average power of the lens system decreases (due to the flattening of the lenslets) and the corresponding total wavefront error figure also decreases, also due to the decrease in contribution of such wavefront error to the non-flattened portions that make up the lenslet surfaces.
Table 2:
| design 1 | RMS OPD WFE： | Area average optical power: |
| 0% compression (Zemax only): | 0.0028 wave | 10.04 diopters |
| 10% compression (zemax+fea): | 1.333 wave | 9.04 diopters |
| 30% compression (zemax+fea): | 12.31 wave | 6.86 diopters |
| 60% compression (zemax+fea): | 9.44 wave | 4.02 diopters |
| 100% compression (Zemax only): | 0.0008 wave | 1.28 diopters |
Example 2: two lenslet series with mutually facing aspheric surfaces
To demonstrate how adding an aspheric term to the spatial profile of the surfaces comprising the lenslets of the lens system of example 1 affects wavefront errors that exist during the process of increasing the overall focal length of the lens system (which corresponds to the process of increasing the flattening of the lenslets; or conversely, during the process of decreasing the focal length of the lens system, which corresponds to the process of decreasing the degree of flattening of the lenslets), the modified embodiment of the lens system of example 1 is considered to be adding a corresponding conic term (conic term) to the surface profile of surfaces II, II-see table 3-thereby modifying these surfaces to optically prolate aspheric surfaces as is commonly understood in the art. By analogy with table 1, table 3 describes the unstressed (non-flattened) state of the lens system so modified, in which surfaces II and III facing each other are in contact with each other only at axial points.
Table 3:
here, when the lens system is subjected to axial compression and the surfaces II, III are progressively flattened against each other, as the surfaces flatten at the interface and the asphericity of the surfaces is removed, their surface profile becomes flatter, allowing the system to approach diffraction limited performance over a wider range of flattening conditions, as demonstrated by the wavefront error figures summarized in table 4.
Table 4: wavefront error and area averaged optical power of example 2:
| design 2 | RMS OPD WFE： | Area average optical power: |
| 0% compression (Zemax only): | 0.0032 wave | 10.03 diopters |
| 10% compression (zemax+fea): | 0.9681 wave | 9.08 diopters |
| 30% compression (zemax+fea): | 8.9155 wave | 6.86 diopters |
| 60% compression (zemax+fea): | 7.7089 wave | 3.96 diopters |
| 100% compression (Zemax only): | 0.0008 wave | 1.28 diopters |
From a comparison of the results summarized in tables 2 and 4, one skilled in the art will readily recognize that adding a prolate aspheric term to the surface profile of surfaces II, III of the dual lenslet design substantially reduces residual wavefront errors caused by surfaces II, II that are not fully flattened during increasing or decreasing focal length of the lens system. While only a few discrete levels of flattening wavefront errors are shown (for reasons that it is impractical to show a very large number of flattening steps), it should be appreciated that this trend and the observed trend of reduced wavefront errors due to the configuration of the mutually facing surfaces that make up the lenslets as prolate aspheric surfaces rather than generally spherical surfaces is generally still effective.
With reference to fig. 3A, 3B and 4A, 4B, 4C and 4D, a greater understanding of the advantages provided by the lens system of example 2 may be obtained by comparing additional details of the optical performance of the lens systems of examples 1 and 2. Fig. 3A and 3B are graphs basically showing the results summarized in tables 2 and 4. As expected by the design of example 1, a smooth monotonic transition in area average power from 10.0 diopters to 1.25 diopters was observed when the lens system underwent compression. In the end state of the uncompressed and fully compressed, the amount of optical aberration is also well within the diffraction limited range. When the design of example 1 experiences axial compression (flattening of surfaces II and III), the wavefront aberration increases and peaks at some intermediate amount of compression. Notably, comparing the numerical scale of the x-axis of fig. 4A-4D with the numerical scale of fig. 2A-2D shows that while in example 2 adding an aspheric term to surfaces II, III does not actually affect the physical profile of the surfaces along the entire radius, such addition reduces the amount of wavefront aberration during focal length transitions experienced by the lens system as a result of being compressed (or vice versa as a result of compression being removed).
Example 3: three lenslet series with substantially spherical surfaces
In this example, an embodiment of a mechanically compliant lens system is configured in a similar manner as example 1, except that three component lenslets are used instead of two component lenslets. Fig. 16A and 16B provide a schematic reference to such an easy-to-visualize configuration. Here, an initial pair of lenslets 110, 120 having substantially spherical surfaces is complemented by a secondary lenslet 1630.
The immediately adjacent ones of the lenslets 110, 120, 1630 are shown in physical contact with each other in an unstressed state. In other words, lenslets 110 and 120 contact at axial point O, O ' of surfaces II and III, and lenslets 120, 1630 contact at axial points O ', O ' of surfaces IV and V. The schematic shape of the lenslets 110, 120, 1630 in a stressed state (caused by the application of an axial force to the surface VI towards the surface I, while the lenslets 110 are fixed in the housing harness) corresponding to the increased radius of curvature of the inner surfaces constituting the lenslets 120, 1630 is shown in fig. 16B, where the flattened areas of the inner surfaces II, IV and V are generally designated 1644, schematically and not to scale. (it should be understood that embodiments having more than three sequentially disposed individual component lenslets of the overall lens system will be constructed in a substantially similar manner).
The embodiment of fig. 16A, 16B is configured to have a diffraction limit of about 10 diopters when not flattened and about 1.25 diopters when substantially fully flattened. However, due to the presence of the additional third lenslet, an additional degree of freedom in the design is allowed, which in this example is manifested by a diffraction limit that requires the system to have a prescribed area average optical power (in this example about 5.71 diopters) when only one of the two pairs of mutually facing surfaces that make up the lenslet is fully flattened and the other pair is not. In other words, in such a design, the availability of more than one pair of constituent lenslets, i.e., the pair of lenslets 110 and 120 in which the mutually flattened surfaces are surfaces II and III, and the pair of lenslets 120 and 1630 in which the mutually flattened surfaces are surfaces IV and V, not only provides the opportunity to reduce wavefront errors during the reversible flattening of the lens system, since the total number of constituent lenslets is increased as compared to examples 1 and 2, but also the opportunity to reduce such errors by flattening only every other pair of mutually facing surfaces of the existing constituent lenslet pairs, rather than flattening each pair of mutually facing surfaces within the lens system. It will be appreciated that in practice, in order to control the set amount of compression of only one immediately adjacent pair of lenslets (and thus, the flattening of only one of the available two pairs of mutually facing surfaces that make up the lenslets) independently of and without affecting the remainder of the lens system, the housing, securing mechanism and/or axial compression of the lenslets should allow for reversible securement of the middle of the three lenslets. (in a related design where the number of constituent lenslets exceeds three, the general approach to achieving flattening of a selected pair of mutually facing surfaces independently of flattening of the other mutually facing surfaces would follow the same logic.)
Table 5 shows the prescription parameters for the lens system of example 3 in the unstressed (non-flattened) state.
Table 6: simulation results of wavefront errors introduced by the lens system of example 3 for different flattening states of the mutually facing surfaces of the different pairs that make up the lenslets:
table 7: simulation results of the area-averaged optical power of the lens system of example 3 for different flattened states of the mutually facing surfaces of the different pairs that make up the lenslets:
notably, the addition of additional lenslets to the lens system significantly reduces the peak of the wavefront error as compared to the design of example 1. It should be appreciated that while the design of example 3 adds only one auxiliary constituent lenslet to the overall lens system, this trend and trend of modification remains with the addition of more than one constituent lenslet, as shown in example 4 below. Alternatively or additionally, the increase in the number of constituent lenslets may be combined with a modification of the spatial profile of the surface of at least one of the pair of mutually facing surfaces of the constituent lenslets (as considered in example 2) to further reduce wavefront errors in adjusting/changing the optical power of the lens system.
Example 4: seven lenslet series with substantially spherical surfaces
As will now be appreciated by those skilled in the art, the idea of increasing the number of constituent lenslets in the overall lens system means that in a related embodiment, a plurality of auxiliary lenslets may be added to the base system of example 1 such that the overall optical system includes a set of four or more constituent lenslets, each of which contacts an immediately adjacent constituent lenslet at a respective axial point when the four or more constituent lenslets are unstressed.
The exemplary embodiment takes the idea of increasing the number of constituent lenslets in a mechanically flexible lens system even further (somewhat arbitrarily) to seven lenses to demonstrate that a continued increase in the number of lenslets inevitably results in a reduction of wavefront errors (due to flattening of at least one pair of mutually facing surfaces of the constituent lenslets) during the process of refocusing the lens system between a near focus state (corresponding to the case of no flattening or stress in the lens system) to a far focus state (corresponding to the case of substantially complete flattening and maximum stress in the lens system). In other words, although this embodiment is not shown in the drawings, in contrast to the embodiment of example 1, the overall lens system additionally comprises a sequence of 5 (five) auxiliary lenslets, each of which contacts an immediately adjacent constituent lenslet at a respective axial point when these plurality of auxiliary lenslets are unstressed.
The seven-fold (7 lenslets) model of the lens system of this example was designed according to the same principles as examples 1 and 4: in the unstressed state, the mutually facing surfaces of immediately adjacent lenslets contact each other only at axial points along the optical axis. Each optical surface is considered to be a spherical surface. The parameters of the seven mirrors range from 1.25 diopters when the lens system is fully compressed to 10.0 diopters when the lens system is unstressed. Here, the assumption (which has been considered in example 4) that the sequential compression of the mutually facing surfaces or interfaces between the closely adjacent lenslets is maintained, the surface radius of curvature is selected such that the optical power of the overall lens system progresses in equal steps from interface to interface throughout the applanation process. Here, for simplicity we first make all surfaces substantially planar (a fully flattened lens system), then solve for the radius of curvature (ROC) for the first and last surfaces (surfaces I and XIV), with a total system diopter of 1.25. The ROC values for surfaces I and XIV are then locked. Then, the parameters of the mutually facing surfaces of the last pair of lenslets (final internal interface; surfaces XII and XIII of lenslets 6 and 7) are considered as variables and a solution of total system power of 1.25D and 1.46D is obtained. This process continues until ROC for all 14 surfaces of the lens system is determined. The resulting heptad mirrors are shown in table 8.
Table 8: prescription parameters for the lens system of example 4 for the unstressed (non-flattened) state.
Table 9: simulation results (in Zemax) of the wavefront error introduced by the lens system of example 4 for different flattening conditions of the different pairs of mutually facing surfaces that make up the lenslets:
compressing/flattening each of the pair of mutually facing surfaces of the lenslets with FEA through three test levels (10%, 30% and 60% displacement, as in examples 1 and 3) will result in 18 different simulations. To reduce the number of simulations, only a pair of constituent lenslets of this design is considered. The pair is then transformed by FEA compression analysis similar to examples 1 and 3, and the RMS-OPD-WFE values are approximated by other compression stages having the profile. For the sake of example, a combination of lenslets 1 and 2 is chosen.
Table 10: parameters for lenslets 1 and 2 representing the various inner lenslet pairs of the lens system of example 4 were chosen:
| ROC of front surface of lenslet | ROC of rear surface of lenslet | |
| Lenslet 1 | +90.406mm (surface I) | +121.014mm (surface II) |
| Lenslet 2 | +90.406mm (surface III) | +121.014mm (surface IV) |
| Not flattened: | and (3) completely flattening: | |
| effective focal length: | 335.715mm | 652.912mm |
| optical power: | 2.98D | 1.53D |
| RMS-OPD-WFE： | 0.0028 wave | 0.0018 wave |
In the next step, FEA (10%, 30%, 60% of the total surface pit displacement, corresponding to three flattening levels of surfaces II and III of the lenslets) is performed for three intermediate compression levels of the lenslet 1/lenslet 2 pair. Table 11 shows the quantitative results of FEA at the interface between surfaces II and III.
Table 11:
since the results/demonstrations of several discrete examples 1 to 4 of the lens system demonstrate not only the different number of constituent lenslets, but also the intentional deviation of the surface profiles of the mutually facing surfaces of immediately adjacent lenslets, which deviation was introduced in order to reduce the wavefront error, the person skilled in the art can now generalize the comparison between the designs considered to derive the graph of fig. 6. Here, for generating the 2D curve, for the embodiments of examples 3 and 4, a sequential interface-by-interface compression scheme is assumed.
Embodiments of the present invention surprisingly demonstrate that in embodiments of a compliant lens system, increasing the number of lenslets reduces the peak of wavefront errors introduced by compressing at least one pair of constituent lenslets to flatten the mutually facing surfaces of the pair of lenslets during the refocusing process of the lens system between a near focus state and a far focus state (as compared to the peak of a lens system having a smaller number of constituent lenslets). For example, curve iii represents the change in wavefront error as the system 1600 of fig. 16A, 16B is flattened in two main sequential steps. First, only a pair of immediately adjacent constituent lenslets (e.g., pairs 110, 120) are flattened, which corresponds to the initial power of the non-flattened system 1600 decreasing from the power corresponding to point iii-A of curve iii to the power corresponding to point iii-B of curve iii. In the first stage of flattening, the wavefront error first increases to a value corresponding to the first "peak" of curve iii and then decreases to substantially zero (at point iii-B). The constituent lenslet pairs 120, 1630 are then flattened to planarize the contact area at surfaces IV, V, which corresponds to a further decrease in optical power of the overall system 1600 from optical power corresponding to point iii-B of curve iii to optical power corresponding to point iii-C of curve iii. At this stage of flattening of system 1600, the change in wavefront error also experiences an initial increase (second peak of curve iii) and a subsequent decrease (at endpoint iii-C).
Similarly, upon sequential application of the system of example 4 (not performed simultaneously for all immediately adjacent pairs of lenslets, but one-to-one), the optical power of the system of example 4 decreases from a value corresponding to the initial optical power (for an unpressed system, point iv-a of curve iv) to a value corresponding to the case when all pairs of surfaces that make up the lenslets face each other are substantially fully flattened (see point iv-C). As indicated by the plurality of "peaks" of the portions of curves iii and iv and the "gaps" between these portions of curves iii and iv (in which the wavefront error value is reduced to a minimum), the non-flattened surfaces of the respective lens systems in the resting (unstressed) state may be designed such that a given N lenslet system (N > 2) has a plurality of empty compressed (flattened) states with minimal wavefront error. These empty states correspond to the case where the interface is uncompressed or fully flattened (when a sequential compression scheme is assumed). Alternatively or additionally, the spatial profiles of the mutually flattened and mutually facing surfaces constituting the lenslets may be modified to introduce a prolate aspherical profile in the axial portion of such surfaces, thereby further reducing the wavefront error.
Example 5: the lens system of the multi-lenslet is subjected to torque applied to the lenslet edges such thatSuch lenslet curvature
In a related embodiment, which implementation may be combined with any of the embodiments of the preceding examples, at least one lenslet of a multi-lenslet lens system is refocused by flattening an inner surface of such lens system, suitably utilized or configured to enable a user to apply a moment/torque to a peripheral edge portion of the lenslet to bend the lenslet either simultaneously with the refocusing process of the lens system or before such refocusing or immediately after a degree of refocusing has been achieved. Fig. 7A and 7B present a schematic illustration of a portion of an embodiment 710 of an edge moment actuator (typically configured as a bearing and in this example as a push ring element) in contact with a peripheral portion of a given lenslet 720 of the overall lens system contained/accommodated in a support structure, a portion of which is shown as 730. For simplicity of illustration, only half of the entire device is shown, with push ring 710 having a diameter less than the diameter of support structure element 730. The contact area or zone between push ring element 710 and lenslet 720 is shown as 710A, while the contact area or zone between lenslet support element 730 and lenslet 720 is shown as 730A. (in this configuration, it will be appreciated that contact regions 710A and 730A have a generally annular shape). The contact regions 710A, 730b are located at different radial positions relative to the optical axis 104.
Fig. 7B shows the spatial distribution of bending stresses throughout lenslet 720 as push ring 710 is axially repositioned toward support structure 730, which remains substantially stationary, thereby indicating the mechanical load applied to lenslet 720. In fig. 7B, the device shown in fig. 7A is rotated 90 degrees. (it should be appreciated that in a related embodiment, element 730 may be configured as part of an edge torque actuator, while element 710 may be configured as part of a lenslet support structure—the principle of applying torque to the perimeter of at least one lenslet of the overall lens system is unchanged, regardless of the specifics of the particular implementation of the edge torque actuator.)
Thus, embodiments of the present invention include an optical system, at least one of which has corresponding first and second contact areas or regions that cooperate with respective supported lenslets of the optical system at two respective different radial positions. Such first and second contact regions are preferably mechanically coupled to each other to transfer a force applied to at least one of these regions to the lenslet to reversibly displace at least a portion of the peripheral edge of the lenslet along the optical axis while not substantially affecting the axial position of the lenslet center.
Similarly, fig. 8A and 8B schematically illustrate, in cross-section, an example of a pair 100 of lenslets 110 and 120, respectively, as part of an overall lens system, whose surfaces II and III are partially flattened, and for comparison, a structurally modified pair 800 of lenslets 810, 820 that are otherwise substantially optically identical to lenslets 810, 820, respectively, is illustrated. As shown in fig. 8B, in contrast to fig. 8A, the lenslets 810, 820 now have moment inducing extensions or "fingers" or haptics 810A, 820A that are sized such that when an axially directed force is applied to at least one of the lenslets 810, 820 to refocus the pair 800, the mutually facing ends of the haptics (which are typically in contact with each other in a steady or stress-free configuration when no flattening of either of the lenslets 810, 820 has occurred) push against each other, thereby creating a torque applied to the periphery of at least one of the lenslets 810, 820 and bending at least one of the lenslets 810, 820. This bending effect is created by shifting at least a portion of the circumferential region (circumferential edge) of at least one of the lenslets along the optical axis while not substantially affecting the axial position of the center of the lenslet being bent.
It is appreciated that the haptics 810A, 820A may alternatively be configured rotationally symmetrical with respect to the optical axis 104 in order to provide optimal application of torque to the lenslets. For example, in at least one instance, the haptics 810A, 820A can be sized, as viewed along the optical axis 104, into a ring or band having a substantially annular shape. In this particular embodiment, each of the haptics 810A, 820A has a respective inner perimeter along which the respective haptic is attached to the peripheral edge of the respective lenslet (810 or 820).
Fig. 9A, 9B, 9C, and 9D schematically illustrate the change in surface depression profile corresponding to different axial compression increments a, B, C, and D (different degrees of applanation) of lenslets 810, 820 as compared to the surface depression profile of lenslets 110, 120 without the circumferential torque-inducing haptic/"finger". The comparison between the respective curves of fig. 9A to 9D and the respective curves of fig. 4A to 4D illustrates the difference due to the presence of the circumferential torque applied to the lenslets of example 5.
Fig. 10A, 10B provide graphs showing, respectively, the change in optical power of pairs of lenslets contacting each other throughout the lens system and the resulting wavefront error introduced by such pairs as a function of the degree of flattening of the surfaces facing each other (surfaces II and III in the case of pairs (110, 120) and (810, 820)). Those skilled in the art will readily appreciate that the use of a circumferential torque applied to a lenslet in combination with a refocusing process based on a flattened pair of lenslets results in a reduction of wavefront errors.
As is known in the art, the comparison of Optical Path Difference (OPD) fans for the embodiments of examples 1, 2, and 5 depicted in fig. 11A, 11B, 11C, 11D, and 11E (the latter representing the embodiment of example 1 structurally modified to include moment-inducing haptics/extensions 810A, 820A according to fig. 8B) shows the appearance of reduced wavefront errors (for the different degrees of applanation of the surfaces II, III of the component lenslets of these examples) as a variation of the OPD fans. The following shorthand notation is used herein: 1 = example 1;2 = example 2;5 = example 5.
According to the inventive concept, torque may be applied to at least one point of the circumferential edge of a lenslet of a lens system, and preferably a plurality of points or portions of the edge, and/or such torque application may be achieved before or preferably simultaneously or after incremental flattening of a portion of the respective lens system (and regardless of the number of lenslets in the lens system, and regardless of whether the flattened surface is aspherical or substantially spherical).
Example 6: reducing lens penetration in multiple lenslets by laterally loading constituent lensletsRe-establishment of embodiments of mirror systems
Wavefront errors introduced during focusing
The illustration of this embodiment of the invention is provided on the example of a part of a lens system comprising two constituent lenslets in an unstressed state (steady state, no axially oriented surface flattening forces present) that are in contact with each other at axial points of surfaces II, III facing each other, similar to the case shown in fig. 1A. At least one of the lenslets 110, 120 is then subjected to a lateral load modeled as a radial displacement of at least one designated portion of the lenslet's perimeter/circumferential edge, and in a related embodiment, an opposing portion of the lenslet's perimeter. In practice, various radial displacements of interest may be achieved with radial loader devices (which may be configured as bearings) attached to the circumferential edge/periphery of a lenslet subjected to lateral loading to apply radially directed forces to such circumferential edge. The radial loader device is not explicitly shown in fig. 12, but is referred to as 1210, may be part of the overall support structure of the lens system, and may be arranged to be movably supported between an inner loader position and an outer loader position. (the inner loader position may be defined at a first radial distance from the optical axis and the outer loader position may be defined at a second radial distance from the optical axis. Here, the second radial distance is greater than the first radial distance.) notably, both the radial loader device and the lateral loading caused by operation of such loader device are different from the haptic structure of an intraocular lens (IOL) and the effects caused by operation of such haptics, as discussed in, for example, PCT/US2014/0580318, because the radially directed force applied to the IOL by operation of the haptics provides an adverse additional increase in axial force due to the particular shape of the haptics.
In the specific example of the embodiment of fig. 12, the radial displacement of the lenslet edge caused by the applied lateral load is shown as 50 microns along the x-axis, then 100 microns and 100 microns. In this example, substantially simultaneously with this diametric stretching of the lenslets of pairs 110, 120, pair 110. 120 are axially compressed (as discussed in other examples) to a level that results in 10%, 30% and 60% dishing of the total interface between surfaces II and III of lenslets 110, 120. The concave profile of the lenslet surface was simulated along the x-axis with the Abaqus FEA software (for only one-fourth of the lens elements to reduce simulation complexity). The surface recess profile in the orthogonal direction (along the y-axis) is assumed to be the same as the surface recess profile in the absence of radial load along the corresponding axis. For each level of radial tension F X And each stage of axial compression F Z Given the concave profile Z of a surface Surf Can be expressed as Z Surf (x,y；F X ,F Z )。
Under a transverse/radial load applied along the x-axis, Z can be obtained according to FEA Surf (x，y＝0；F X ，F Z ). Assuming that the profile in the orthogonal unstretched (y-) direction is similar to that of pure axial compression, Z can be obtained Surf (x＝0，y；F X ，F Z )＝Z Surf (x＝0，y；F X ＝0，F Z ). Then, in the next step, the concave profile Z is set along the oblique direction between the x-axis and the y-axis Surf Appropriate interpolation is performed. To perform such interpolation, a concave profile for each of the four basic directions (±x and±y) is first determined. The skilled person will understand that what profile to use for each of the four basic directions (±x and±y) depends on the aberrations we are looking to study: astigmatism, coma, and spherical aberration. For astigmatism, we use the results from the lateral loading FEA for the ± X recess profile and assume that the ± Y recess profile is equal to the profile of the example 1 embodiment. For coma we use the lateral loading FEA results for the +x concave profile and assume that the-X and Y concave profiles are equal to the profile of example 1. For spherical aberration, we use the lateral loading FEA results for all ± X and ± Y pit profiles. Regarding interpolation, consider a pure paraboloid. By converting the concave profile of a given surface to polar coordinates (i.e., according to radial and angular coordinates), the following transformations may be performed:
Z＝Ax 2 +By 2 x＝rcosθ；y＝rsinθ；sin 2 θ＝1-cos 2 θ; and
Z＝(A-B)r 2 cos 2 θ+Br 2
here, it was found that the concavity of the profile of a given surface of the lenslet is substantially linear with the square of the cosine of the angular coordinate. Assuming that the azimuthal characteristics of the lenslets to be modeled are parabolic, such an interpolation scheme (based on the square of the angle cosine) may be used. Fig. 13A, 13B, 13C, and 13D show screen shots of results of simulating the specified axial compression of lenslet pairs 110, 120 with Abaqus FEA software under different conditions: in the absence of lateral loading (fig. 13A), the lateral loading caused an edge displacement of the lenslets of 50 microns (fig. 13C), the lateral loading caused an edge displacement of the lenslets of 100 microns (fig. 13B), and in the case of lateral loading caused an edge displacement of the lenslets of 150 microns.
Fig. 14A, 14B, 14C provide a qualitative illustration of the process of varying the degree of applanation of the surfaces II, III of a pair of lenslets 110, 120 (of the overall lens system comprising such a pair of lenslets) with a lateral loading (with radial vector forces applied to the circumferential edges of the lenslets 120) to stretch the lenslets 120 in a direction transverse to the optical axis OA. 14A, 14B, 14C include a surface plot on the left side of the respective figure representing the lateral load type of lenslet 120, and a plot representing the identified Zernike aberration terms as a function of the different degrees of compression of the identified pair 110, 120 (corresponding to the different degrees of applanation of surfaces II, III, and thus to the different sizes of contact flats between the lenslets 110, 120 and the different optical powers of the pair 110, 120).
Here, described is a Zernike circle polynomial known in the related art (and therefore not discussed in any detail herein), which mathematically describes a 3-D wavefront deviation (i.e., deviation from zero values of the polynomial as a function of the change in radial coordinate ρ and angular coordinate θ) from a plane that can be constructed as its zero mean, i.e., a plane of unit circles, defined as a surface where the sum of the deviations on either side (sign opposite to each other) is equal to zero. Each polynomial describes a particular form of surface deviation; their combination and result in a number of more complex surface shapes that can be fitted to a particular form of wavefront deviation (aberration). As is known in the art, in principle, by including a sufficient number of Zernike polynomials (commonly referred to as terms), any wavefront deformation can be described with a desired degree of accuracy.
The surface curve of fig. 14A shows the case where lateral loading forces are applied to the edges of the lenslets 120 at two diametrically opposed points, for example to stretch the lenslets 120 at these points in two opposite directions perpendicular to the optical axis, while the variation of astigmatism introduced by the pairs 110, 120 is shown in the right-hand graph of fig. 14A. The surface curve of fig. 14B shows the case where the lateral loading force is applied to the edge of the lenslet 120 at only one point (while keeping the lenslet 120 centered on the optical axis), resulting in a unidirectional stretching of the lenslet 120 along its diameter, while the variation in coma introduced by the pairs 110, 120 is presented to the right in fig. 14A. The surface plot of fig. 14C shows the situation when a lateral loading force is applied radially onto the periphery of the lenslet 120 at each point of the periphery of the lenslet 120, thereby causing the lenslet 120 to stretch away from the optical axis in an omni-directional manner, while the spherical aberration introduced by the pairs 110, 120 is shown to the right.
These results obtained by modeling the Zernike aberrations using Zemax demonstrate that by combining/coupling axially directed forces that cause applanation of the lenslet surface with loading forces applied laterally onto the provided optical axis, not only can the identified Zernike aberrations corresponding to the specified lateral loading geometry be changed/managed, but other Zernike aberrations can be changed/managed, with the appropriate lenslet actuator scheme in place.
It will be appreciated that the generally proposed method of operating a lens system comprising a plurality of elastically deformable lenslets to change the optical power (focal length) of such a system by varying the degree of flattening of at least a pair of mutually facing surfaces of the constituent lenslets may incorporate any and/or each additional/auxiliary effect on the constituent lenslets of the system to reduce wavefront errors that would otherwise accompany the refocusing process of the optical system without such additional effect. In these additional actions, at least a predetermined asphericity is added to the spatial profile of the flattened lenslet surface, and/or the same optical system is implemented in a form in which the number of constituent lenslets is significantly increased while otherwise maintaining the optical power of the overall system substantially the same in a stress-free state, and/or the spatial profile of the flattened lenslet is altered by bending the flattened lenslet relative to the optical axis, and/or a radial vector force is applied to at least a portion of the outer circumference of the flattened lenslet to affect the predetermined optical aberration introduced by such lenslet.
In general, each and/or each additional/auxiliary action of bending a lenslet and applying a radial vector force to at least a portion of the outer circumference of the flattened lenslet may generally be performed immediately after, or substantially simultaneously with, or immediately after, an incremental refocusing action that results in an increase in the change in optical power of the system by applying an external force to at least one lenslet of the system along the axis. Each action performed on a lenslet of the overall optical system may be performed with an appropriate corresponding portion of a support structure containing such a lenslet (in at least one case, the support structure may be defined by an overall housing structure at least partially enclosing the optical system) and a computer processor or microprocessor or electronic circuit programmed to apply a stimulus to such a support structure to enable the portion to move/translate in a predetermined direction (axial and/or radial, depending on the implementation details) to thereby apply a respective external force to the lenslet of interest.
Without reference to any particular example of the constituent lenslet series of the embodiments of the monolithic optical system discussed so far, and merely to schematically illustrate one possible implementation of the monolithic system of the present invention, fig. 15A, 15B, 15C, and 15D provide schematic illustrations of side and front views of one embodiment 1500 of a multi-lenslet zoom lens system constructed and operative in accordance with the concepts of the present invention. Generally, the lens system of the present invention includes a sequence (array) of individual lenslets (shown as lenslets 1510, 1520, 1530, 1540) that are sequentially and coaxially disposed about an optical axis (shown here as 1550) within a housing 1560, the housing 1560 having an outer shell defining a hollow volume therein. The front surface of lens 1510 (surface I, not labeled) corresponds to the front of the lens system. Individual lenses 1510, 1520, 1530, and 1540 are disposed in the hollow and supported by a support structure sized to support the lens system (1510, 1520, 1530, 1540) and designated 1562 (but not shown separately from the housing in the figures for simplicity of illustration, alternatively but preferably, support structure 1562 includes individual lenslet support elements, generally designated 1562A, 1562B … 1562N, but also not shown separately from the housing/support structure for simplicity of illustration). The housing 1560 may be provided with suitable stop elements (not shown) at the front 1564 of the housing 1560 to retain the constituent lenslets within the hollow portion of the housing. As shown in the specific example of fig. 15A, every two immediately adjacent lenslets abut each other at a respective axial point such that the mutually facing surfaces of the two immediately adjacent lenslets contact each other at the respective axial point. For example, as shown, surfaces II, III of the system (corresponding to lenses 1510, 1520, respectively) contact at axial point C, while surfaces VI, VII of the system (corresponding to lenses 1530, 1540, respectively) contact at axial point S. For simplicity of illustration, surfaces IV and V of system 1500 (the rear surface of lenslet 1520 and the front surface of lenslet 1530, respectively) are not indicated. The lenslet sets 1530, 1540 may represent a plurality of auxiliary lenslets as mentioned elsewhere in this disclosure. At least one of the pair of mutually contacting surfaces of the lens system 1500 of the present invention may be an aspheric surface in accordance with the concepts of the present invention. For example, at least one of the surfaces II, III may have an aspherical profile about the axis 1550. Lenslets with non-spherical surfaces (or aspheres) are known in the art as lenslets whose surface profile is not part of a sphere or cylinder (i.e., is not part of a sphere or cylinder surface). An aspherical surface profile is generally defined as a function representing the displacement of a surface from an apex at a given distance from the optical axis. Parameters of such a function include radius of curvature and conic constant (or conic parameter) defined at the vertex. The term surface is used to denote a boundary between two media or a boundary or spatial limitation of a tangible element; a surface is understood to be of length and width but not thickness.
At the rear of housing 1560, lenslet support elements and/or bearings, shown as actuation pistons 1570, cooperate (as known in the art) to, for example, allow for application of pressure or axial force to the lenslet sequence due to movement of pistons 1570 along axis 1550. Fig. 15A and 15B illustrate the state of embodiment 1500 when bearing 1570 is in a neutral position defined by axial forces without interaction between the lenslets of the system and the piston surfaces. In these cases, as shown in the front view of fig. 15B, any inner surfaces of the lens system are substantially not flattened or flattened (in other words, each of the constituent lenses 1510, 1520, 1530, and 1540 maintain their original unstressed shape). In operation (and with reference to fig. 15C, 15D), bearing 1570 is actuated along axis 1550-e.g., in the direction indicated by arrow 1574-to apply axially-oriented (oriented along the optical axis) pressure to individual lenses of system 1500. In general, according to the concepts of the present invention, when the lens system comprises at least one auxiliary lenslet (1530, 1540) in addition to the basic pair of first and second lenslets (1510, 1520), the support structure of the optical system comprises an auxiliary bearing that movably connects the auxiliary lenslet support element to the support structure and/or the first and/or second lenslet support element, such that the auxiliary lenslet support element (and thus the respective auxiliary lenslet) can be translated relative to the first and/or second lenslet support element in response to an auxiliary external force, such that the at least one auxiliary lenslet and the selected lenslet are pressed against each other along the optical axis by varying the auxiliary external force, or such that the axial pressure exerted by one of the at least one auxiliary lenslet and the selected lenslet on the other of the two is relaxed, to vary the contact area between the surface of the at least one auxiliary lenslet and the surface of the selected lenslet (the auxiliary lenslet at the axial point with the flattened contact area of the selected lenslet).
It should be understood that rootDepending on the particular design, the support structure in a given optical system may include multiple lenslet support elements and/or corresponding bearings to judiciously apply pressure to any predetermined constituent lenslets of the system, e.g., to the outermost lens 1540 (thereby creating a force F1574 that is directed along the optical axis 1550 and axially compresses the combination of lenses 1510, 1520, 1530, and 1540), or to another lenslet in the system, or to multiple constituent lenslets of the system, but not necessarily all. This generalized concept is represented in fig. 15A, 15B by additional designations 1570A, 1570B … … 1570N, which are intended to represent individual lenslet support elements/bearings, each of which is configured to cooperate with a particular component lenslet of the system to apply a respective axial force 1574A, 1574B … … 1574N. In one particular implementation, for example, bearing 1570 may be configured to apply pressure only to lenslet 1520, thereby axially compressing lenses 1510 and 1520 to planarize or increase the radius of curvature of at least one of the mutually facing surfaces II, III. In another particular case, as in fig. 15A, bearing 1570 is configured to compress the entire set of constituent lenslets of embodiment 1500 by applying an axial force to outermost lenslet 1540 proximate bearing 1570. As a result, at least one of the surfaces of the immediately adjacent lenslets facing each other is deformed according to the strength of the axially applied force caused by the movement of the bearing 1570, as on such surface an axially centered flattened (i.e., centered on the optical axis and flattened compared to the shape of the individual lenslet) region 1580 is formed. The radius of the flattened area 1580 (and thus the surface area of the area 1580) increases with increasing force F and decreases as the strength of the force F decreases. FIG. 15D shows a progression 1580A of such flattened areas 1580, wherein the corresponding radii R i As the force F increases.
It will be appreciated that in one embodiment, the two mutually facing surfaces of two immediately adjacent lenslets are configured to change their curvature at least at the optical axis of the system and/or at the respective regions around the optical axis. In at least one implementation of the system of fig. 15A, 15B, 15C, 15D, the curvature of both surfaces II and III and/or the curvature of both surfaces IV and V and/or the curvature of both surfaces VI and VII may decrease or increase in response to repositioning of piston 1570, depending on the direction of such repositioning relative to the front of lens system 1500. It is appreciated that the planarization process of the at least one axially centered region 1580 comprising the lenslet surface is reversible and repeatable. To this end, the material comprising the lenslets acts as a spring reversing the actuation of the lens in proportion to the decrease in actuation pressure at piston 1570.
In one particular implementation, the housing 1560 may be a cylindrical configuration made of a rigid material (e.g., metal), while the actuation cylinder of the bearing 1570 or the like may be made of an optically transparent material (e.g., polymethyl methacrylate, PMMA) having an elastic modulus of greater than 1000 kPA. The first lenslet 1510 in the lenslet series may also be made rigid with a high elastic modulus (e.g., that of PMMA). The remainder of the inner constituent lenslets (as shown, lenses 1520, 1530, and 1540) may be composed of a softer material with an elastic modulus in the range of 0.1kPa to 100kPa, such as silicone, acrylic, or collagen (collamer). At least one inner surface (such as, for example, surface II and/or surface III and/or surface VI) may be compressed between rigid bearing 1570 and rigid lenslet 1510 as the bearing moves toward the front of system 1500, thereby increasing diameter 2R with the surface i Upper flattening, gradually counteracting the contribution of these surfaces to the power of the overall lens system 1500, as shown in fig. 15C. Optionally but preferably, such deformable surfaces may be sized as aspheres (e.g., prolate aspheres) with such conic constants as to i) increase sphericity of such surfaces as a result of gradual flattening caused by mechanical compression caused by force F starting from the apex of a given surface; ii) minimizing discontinuities in the spatial transition between flattened portions of the surface (centered on axis 1550) and portions of the lenslet surface surrounding such flattened regions, and (iii) minimizing optical aberrations throughout the range of power variations such that the shape of the aspheric surface in question becomes more planar as the mutually facing inner surfaces of the lens system are progressively flattened. Should be treatedAs will be appreciated, for the examples discussed elsewhere in this disclosure, the lenslets 1510, 1520 of the embodiment of fig. 16A may correspond to lenslets 110, 120 may be represented.
A related method of operating a lens system (optical system) comprising a plurality of compliant (elastically deformable) constituent lenslets includes: the process of refocusing the lens system as a result of repositioning the at least one surface of the at least one constituent lenslet along the optical axis during varying degrees of flattening of the inner surface of the at least one constituent lenslet, and is complemented by one or more processing steps whose implementation allows the user to reduce wavefront errors caused by such varying degrees of flattening, as considered in the examples given above. Specifically, an embodiment of a method for operating an optical system having an optical axis includes the steps of (a) transmitting light incident on a front surface of the optical system having a first optical power through two surfaces of a first lenslet and a second lenslet of the composition of the optical system (the lenslets being coaxial with the optical axis and in contact with each other at a first contact zone having a first contact surface area and centered on the optical axis). The method further includes the step (b) of changing the optical power of the optical system from a first optical power to a second optical power by axially repositioning a first surface of the two surfaces along the optical axis to form a second contact zone between the first surface and the second surface of the two surfaces. (here, the second contact region has a substantially flat surface and has a second contact surface area different from the first contact surface area). The method further comprises one or more of the following additional steps: a step (c) of changing the auxiliary external force to compress at least one auxiliary lenslet and a selected lenslet of the composed first and second lenslets against each other along the optical axis or to relax the axial pressure exerted by one of the at least one auxiliary lenslet and the selected lenslet on the other, thereby changing the flattened contact area between the surface of the at least one auxiliary lenslet and the surface of the selected lenslet; and (d) displacing at least a portion of the circumferential edge of at least one constituent lenslet of the optical system along the optical axis while not substantially affecting the axial position of the center of the at least one constituent lenslet. Example 5 provides an alternative but non-limiting embodiment of the related implementation of step (d). Additionally or alternatively, such implementation of the method may be implemented wherein at least one of steps (b) and (c) comprises varying the degree of flattening of the first and/or second aspheric surfaces of the two mutually facing surfaces of the constituent lenslets of the optical system. Furthermore, alternatively or additionally, step (f) of applying a radially directed load to the circumferential edge of at least one component lenslet of the optical system is used together with steps (a) and (b). As described above, the combination of steps (c) and/or (d) and/or (e) and/or (f) with steps (a) and (b) allows the user to reduce the optical wavefront error introduced by the lens system in operation.
Whether or not a particular processor/microprocessor/electronic circuit is shown in the figures (which may be used to control the refocusing operation of the embodiment of the lens system in question), such a microprocessor is controlled by instructions stored in a memory. The memory may be Random Access Memory (RAM), read Only Memory (ROM), flash memory, or any other memory suitable for storing control software or other instructions and data, or a combination thereof. Those skilled in the art will also readily appreciate that instructions or programs defining the functions of the present invention can be delivered to a processor in a variety of forms, including, but not limited to, information permanently stored on non-writable storage media (e.g., a read-only memory device within a computer such as ROM or a device readable by a computer I/O accessory such as a CD-ROM or DVD disk), information variably stored on writable storage media (e.g., a floppy diskette, removable flash memory, and hard disk drive), or information delivered to a computer via a communication medium (including a wired or wireless computer network). Furthermore, while the present invention may be implemented in software, the functions necessary to implement the present invention may alternatively or in part or in whole be implemented using firmware and/or hardware components such as combinational logic, application Specific Integrated Circuits (ASICs), field Programmable Gate Arrays (FPGAs), or other hardware or some combination of hardware, software, and/or firmware components.
For the purposes of this disclosure and the appended claims, the expression of the type "element a and/or element B" has the meaning of covering an embodiment having individual element a, individual element B, or elements a and B joined together, and as such, is intended to be equivalent to "at least one of element a and element B".
Reference throughout this specification to "one embodiment," "an embodiment," "related embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with the "embodiment" is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. It should be understood that no portion of the disclosure, either alone or in combination with the figures, is intended to provide a complete description of all the features of the invention. In this specification, embodiments have been described in a manner that enables a clear and concise description to be written, but it is intended and will be appreciated that the embodiments may be variously combined or separated without departing from the scope of the invention. In particular, it should be understood that all features described herein apply to all aspects of the invention.
When features of the present invention are described in the present disclosure with reference to the corresponding drawings (where like numerals represent the same or similar elements, where possible), the structural elements depicted are generally not to scale and certain components are exaggerated relative to other components for purposes of emphasis and understanding. It should be understood that no single figure is intended to support a complete description of all the features of the invention. In other words, a given drawing typically depicts only some, but not typically all, of the features of the invention. For the purposes of at least simplifying a given drawing and discussion and directing the discussion to particular elements in that drawing, the relevant portions of the disclosure that are given and contain descriptions that refer to that drawing typically do not contain all elements of a particular view or all features that may be present in that view. Those skilled in the art will recognize that the invention may be practiced without one or more of the specific features, elements, components, structures, details, or characteristics, or with other methods, components, materials, and so forth. Thus, although specific details of embodiments of the invention may not necessarily be shown in each drawing describing such embodiments, the presence of such specific details in the drawings may be suggested unless the context of the description otherwise requires. In other instances, well-known structures, details, materials, or operations may not be shown or described in detail in a given drawing to avoid obscuring aspects of the embodiments of the invention in question. Furthermore, the described individual features, structures, or characteristics of the invention may be combined in any suitable manner in one or more additional embodiments.
Furthermore, if a schematic flow chart diagram is included, the depicted order and labeled steps of the logic flow indicate one embodiment of the presented method. Other steps and sequences of steps may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the illustrated method. Without loss of generality, the order in which the process steps or particular methods occur may or may not strictly adhere to the order of the corresponding steps shown.
For the purposes of this disclosure and the appended claims, the use of the terms "substantially," "approximately," "about," and similar terms to refer to a value, element, attribute, or feature at hand is intended to emphasize the recited value, element, attribute, or feature, though not necessarily exactly the same as that described, but nonetheless may be considered as being described by one of ordinary skill in the art for practical purposes. When applied to a particular characteristic or quality descriptor, such terms mean "substantially", "primarily", "equivalent", "substantially", "to a great or significant extent", "most but not necessarily exactly the same", so as to reasonably represent the approximate language and describe the particular characteristic or descriptor, so that its scope will be understood by those of ordinary skill in the art. The use of this term in describing a selected feature or concept does not imply nor provide a basis for any uncertainty, nor add numerical limitations to a particular feature or descriptor. As will be appreciated by those of skill in the art, the actual deviation of such a value, element or property from the exact value, element or property may be varied within the scope defined by experimental measurement errors that are typical when using accepted measurement methods in the art for such purposes. By way of example only, reference to a vector or line or plane being substantially parallel to a reference line or plane should be construed as such vector or line extending along a direction or axis that is the same as or very close to the reference line or plane (angular deviations from the reference direction or axis are considered to be practically typical in the art, e.g. between 0 and 15 degrees, more preferably between 0 and 10 degrees, even more preferably between 0 and 5 degrees, most preferably between 0 and 2 degrees). The term "substantially rigid" when used in reference to a housing or structural element that provides mechanical support for the device in question, generally identifies a structural element that is more rigid than the device that the structural element supports. As another example, the use of the term "substantially planar" with respect to a particular surface means that such surface may have a degree of non-planarity and/or roughness, the size and expression of which are generally understood by those of skill in the art in the particular context at present. For example, the terms "about" and "about," when used in reference to a numerical value, mean a range of plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, and most preferably plus or minus 2% relative to the specified value.
The invention as set forth in the claims appended hereto is intended to be assessed in light of the entirety of the present disclosure, including the features disclosed in the prior art to which reference is made.
List of reference numerals
100. At least a part of the lens system
104. Optical axis
110. 120 lens system composition lenslets
710. 730 bearing/lenslet support element
710A, 730A contact area between bearing/lenslet support element and corresponding lenslet
800. At least a part of the lens system
810. Composition lenslets of 820 lens system
810A, 820A moment inducing extension from lenslet/haptic
1500 optical system
1510. Composition lenslets of 1520, 1530, 1540 optical systems
1550. Optical axis
1560. Shell body
1562. Supporting structure
1562A, 1562B … … 1562N respective lenslet support element
1564 case front
1570. 1570A, 1570B … … 1570N bearing
1574. 1574A, 1574B … … 1574N axially directed forces
1600. At least a part of the lens system
1630. Composition lenslets of lens systems
I. II, III, IV, V, VI, VII, etc.
Claims (16)
1. A method for operating an optical system having an optical axis, the method comprising at least the steps of:
Transmitting light incident on a front surface of an optical system having a first optical power through two surfaces of a first lenslet and a second lenslet of the composition of the optical system, the two surfaces being coaxial with the optical axis and in contact with each other at a first contact zone having a first contact surface area and centered on the optical axis;
changing the optical power of the optical system from the first optical power to a second optical power by axially repositioning a first surface of the two surfaces along the optical axis to form a second contact zone between the first and second surfaces, the second contact zone having a substantially planar surface and having a second contact surface area different from the first contact surface area;
characterized in that the method further comprises at least one of the following steps:
(1a) Changing an auxiliary external force to compress at least one auxiliary lenslet and a selected lenslet of the composed first and second lenslets against each other along the optical axis, or to relax an axial pressure exerted by one of the at least one auxiliary lenslet and the selected lenslet on the other, thereby changing a flattened contact area between a surface of the at least one auxiliary lenslet and a surface of the selected lenslet;
And/or
(1b) Shifting at least a portion of a circumferential edge of at least one of the constituent lenslets of the optical system along the optical axis while not substantially affecting an axial position of a center of the at least one of the constituent lenslets;
and/or
(1c) Wherein at least one of the following comprises a degree of flattening of a first aspheric surface and/or a second aspheric surface of two mutually facing surfaces of a lenslet that alters the composition of the optical system:
the changing the optical power of the optical system from the first optical power to the second optical power by axially repositioning a first surface of the two surfaces along the optical axis, and
said varying said auxiliary external force;
and/or
(1d) A radially directed load is applied to a circumferential edge of at least one of the constituent lenslets of the optical system.
2. The method of claim 1, the alternative (1 b) being characterized by:
at least a portion of a circumferential edge of at least one of the constituent lenslets of the optical system that is shifted along the optical axis includes:
moving at least a portion of a peripheral edge of at least one of two immediately adjacent constituent lenslets of the optical system by transmitting an axial force applied to the at least a portion of the peripheral edge via haptics of the two constituent lenslets connected to each other at their ends, or
Moving at least a portion of a circumferential edge of at least one of two immediately adjacent constituent lenslets of the optical system by applying an axially directed force to one of a first region and a second region of a surface of the at least one lenslet, wherein the first region and the second region are located at two respective different radial positions of the surface.
3. The method of claim 2, wherein the transmitting comprises applying the axial force to a haptic having an annular region with an inner perimeter, wherein the inner perimeter defines the circumferential edge and is attached to the circumferential edge.
4. A method according to any one of claims 1 to 3, wherein at least one of said changing the auxiliary external force, said reversible displacement, said changing the flattening of the first and/or second aspheric surfaces, and said applying a radially directed load is substantially simultaneous with said changing the optical power of the optical system from the first optical power to the second optical power and/or said changing the auxiliary external force.
5. The method of any one of claims 1 to 4, wherein said changing the optical power of the optical system from the first optical power to the second optical power, said changing the auxiliary external force, said shifting, said changing the degree of flattening of the first and/or second aspheric surfaces, and said applying the radially directed load are each performed reversibly.
6. Method according to any one of claims 1 to 5, characterized in that the step of displacing and/or the step of varying the degree of flattening of the first and/or second aspheric surfaces and/or the step of applying a radially directed load, the respective steps being performed only on a subset of the constituent lenslets of the optical system, but not on all constituent lenslets.
7. The method of claim 6, wherein the subset includes every other constituent lenslet from the full constituent lenslets of the optical system.
8. The method according to any one of claims 1-7, the alternative (1 a) being characterized in that:
(8a) The extent to which the flattened contact area between the surface of the auxiliary lenslet and the surface of the selected lenslet is varied depends on the extent to which the auxiliary external force is varied,
And/or
(8b) When the at least one auxiliary lenslet and the selected lenslet are unstressed, the at least one auxiliary lenslet is in contact with the selected lenslet of the constituent first and second lenslets at an axial point of the surface of the at least one auxiliary lenslet,
and/or
(8c) The varying the secondary external force includes pressing a sequence of a plurality of secondary lenslets against the selected lenslet or relaxing an axial pressure exerted by the sequence and the selected lenslet on one another, thereby varying a plurality of flattened contact areas between surfaces of the plurality of secondary lenslets that contact one another at respective axial points when the plurality of secondary lenslets are unstressed.
9. An optical system having an optical axis and comprising at least:
a first lenslet (1510) coaxial with the optical axis (1550) and having a first front surface (I) and a first rear surface (II),
a second lenslet (1520) arranged coaxially with the first lenslet (1510) and having a second front surface (III) and a second rear surface (IV),
wherein the first rear surface (II) and the second front surface (III) are in contact with each other at an axial point on the optical axis when the first lenslet and the second lenslet are unstressed;
A support structure (1562) comprising a first lenslet support element (1562A) supporting the first lenslet (1510) and a second lenslet support element (1562B) supporting the second lenslet (1520),
a first bearing (1570A) and/or a second bearing (1570B) movably connecting the first and/or second lenslet supporting elements with respect to each other and/or the supporting structure such that the first and/or second lenslet supporting elements are capable of translating substantially parallel to the optical axis and/or varying a stress applied to at least one of the respectively supported first and second lenslets, wherein the varying of the stress allows for flattening at least one of the first and second rear surfaces and the second front surface and enables a change in the contact area between the first and second rear surfaces and the central optical axis (2) by applying a first external force pushing or retracting at least one of the first and second lenslet supporting elements (1510, 1520) with respect to the other and/or by applying a second external force vectoring to the first and/or second lenslets (10, 20) substantially transverse to the optical axis,
Characterized in that the optical system satisfies one or more of the following conditions:
(9a) The support structure (1562) further comprises an auxiliary lenslet support element (1562C) supporting at least one auxiliary lenslet (1530) coaxial with the optical axis (1550) and contacting a surface of a selected lenslet of the first and second lenslets of the optical system (1550) only at its axial point when the selected lenslet is unstressed,
wherein the support structure further comprises an auxiliary bearing movably connecting the auxiliary lenslet support element (1562C) to the support structure and/or the first lenslet support element (1562A) and/or the second lenslet support element (1562B), such that a change in the flattened contact area between the surface (V) of the at least one auxiliary lenslet and the surface (IV) of the selected lenslet is enabled in response to an auxiliary external force by changing the auxiliary external force to press the at least one auxiliary lenslet and the selected lenslet against each other along the optical axis or to relax an axial pressure exerted by one of the at least one auxiliary lenslet and the selected lenslet on the other;
Wherein the change in the auxiliary external force flattens the surface of the at least one auxiliary lenslet and/or the surface of the selected lenslet and enables a change in an auxiliary contact surface area between the surface of the at least one auxiliary lenslet (1530) and the surface of the selected lenslet; and/or
(9b) At least one of the lenslet supporting elements (1562A, 1562B, 1563C) present in the optical system has a corresponding first contact region (710A) and a second contact region (730A) that cooperate with a corresponding lenslet (720) of the optical system at two respective different radial positions, and wherein the first contact region (710A) and the second contact region (730A) are mechanically coupled to each other to transfer a force applied to at least one of the first contact region and the second contact region onto the corresponding lenslet (720) to reversibly displace at least a portion of a circumferential edge of the corresponding lenslet along the optical axis while substantially not affecting an axial position of a center of the corresponding lenslet;
and/or
(9c) Two immediately adjacent lenslets (810, 820) of the constituent lenslets of the optical system include respective haptics (810 a,820 a) extending radially from the circumferential regions of the two immediately adjacent lenslets, the respective haptics being sized to contact each other at respective ends thereof to transfer an axial force applied to at least one of the two immediately adjacent lenslets to at least a portion of a circumferential edge of at least one of the two immediately adjacent lenslets to reversibly displace at least the portion along the optical axis while not substantially affecting an axial position of a center of at least one of the two immediately adjacent lenslets;
And/or
(9d) Wherein at least one of the surfaces of the two immediately adjacent lenslets that face and contact each other comprises, in a stress-free state, an aspheric surface centered on the optical axis;
and/or
(9e) Wherein the support structure further comprises a radial loader device movably supported between an inner loader position and an outer loader position, wherein the inner loader position is defined at a first radial distance from the optical axis and the outer loader position is defined at a second radial distance from the optical axis, wherein the second radial distance is greater than the first radial distance,
wherein the radial loader device is attached to respective circumferential edges of at least one of the first lenslet, the second lenslet, and the at least one auxiliary lenslet to apply radially directed forces thereto.
10. The optical system of claim 9, wherein the support structure comprises a housing unit defining a hollow thereon, respective portions of the first lenslet, the second lenslet, and the at least one auxiliary lenslet being disposed in the hollow, and wherein respective portions of at least one of the first support element, the second support element, and the auxiliary support element are sized to reversibly move in the hollow along the optical axis.
11. The optical system of claim 10, wherein the respective portion of at least one of the first support element, the second support element, and the auxiliary support element comprises a piston, or wherein a surface of the hollow is threaded, the threads being sized to guide the respective portion of at least one of the first support element, the second support element, and the auxiliary support element.
12. The optical system according to any one of claims 9 to 11, alternatively (9 a), wherein the at least one auxiliary lenslet comprises a plurality of auxiliary lenslets, such that the optical system comprises a set of four or more constituent lenslets, each constituent lenslet contacting an immediately adjacent constituent lenslet at its axial point when the four or more constituent lenslets are unstressed.
13. The optical system according to any one of claims 9 to 12, alternatively (9 b), wherein at least one of the first contact region (710A) and the second contact region (730A) is at least part of a ring centered on the optical axis (104).
14. Optical system according to one of the preceding claims, alternatively (9 c), characterized in that the haptics comprise respective annular portions, each annular portion having an inner periphery attached to the peripheral edges of respective lenslets of the two immediately adjacent lenslets.
15. Optical system according to one of the preceding claims, alternatively (9 d), characterized in that the aspheric surface is an oblong aspheric surface.
16. Use of an optical system according to one of claims 9 to 15 for performing the method according to one of claims 1 to 8.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US63/140,195 | 2021-01-21 | ||
| US202163196327P | 2021-06-03 | 2021-06-03 | |
| US63/196,327 | 2021-06-03 | ||
| PCT/US2022/013097 WO2022159561A1 (en) | 2021-01-21 | 2022-01-20 | Reducing effects caused by formation of multiple foci in a deformable lens during changes of applanation of surfaces thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116615682A true CN116615682A (en) | 2023-08-18 |
Family
ID=87682342
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280006848.8A Pending CN116615682A (en) | 2021-01-21 | 2022-01-20 | Reducing effects in surface flattening variations caused by the formation of multiple focal points in a deformable lens |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116615682A (en) |
-
2022
- 2022-01-20 CN CN202280006848.8A patent/CN116615682A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7304292B2 (en) | adaptive lens | |
| JP6475156B2 (en) | Improvements to and modifications to deformable membrane assemblies | |
| JP6475834B2 (en) | Macro lens | |
| JP4945558B2 (en) | Intraocular lens for astigmatism | |
| JP2021508854A (en) | Optical design method of imaging system and optical system designed using it | |
| Hasse et al. | Poisson induced bending actuator for soft robotic systems | |
| Liang et al. | Biomimetic optical system using polymer lenses with tunable focus | |
| Nie et al. | Direct design approach to calculate a two-surface lens with an entrance pupil for application in wide field-of-view imaging | |
| CN116615682A (en) | Reducing effects in surface flattening variations caused by the formation of multiple focal points in a deformable lens | |
| EP4062209B1 (en) | Reducing effects caused by formation of multiple foci in a deformable lens during changes of applanation of surfaces thereof | |
| Sieber et al. | Tunable refraction power by mutual rotation of helical lens parts | |
| Du et al. | Bionic optical imaging system with aspheric solid–liquid mixed variable-focus lens | |
| CN109946829A (en) | Zoom is surely as distorting lens zoom face shape design method in Integral imaging system | |
| Genberg et al. | Integrating MD Nastran with optical performance analysis | |
| Zhang et al. | Focus-tunable imaging analyses of the liquid lens based on dielectric elastomer actuator | |
| Genberg et al. | Optical interface for MSC. Nastran | |
| Lemared et al. | Stress mirror polishing for future large lightweight mirrors: design using shape optimization | |
| Ruckert | Improvement of the properties of a variable focus elastic lens by Finite Element optimization | |
| Santiago-Alvarado et al. | Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye | |
| Jaskó et al. | Active array design for FAME: freeform active mirror experiment | |
| Ivaniuk et al. | Augmented reality (AR) display design based on freeform optics | |
| JP2023531381A (en) | Controllable lens actuated via flexion joint | |
| Genberg et al. | Opto-Mechanical I/F for ANSYS | |
| JPS6167014A (en) | Variable aberration lens | |
| Diaz-Gonzalez et al. | Simulation of the optical performance of refractive elements to mimic the human eye focusing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication |