Tunable acoustic gradient lens with axial conformity section

Abstract

Tunable acoustic gradient lens (TAG lens) (170A - F) comprising the following: a controllable sound wave generating element (220); a light-refracting fluid (250); a lens housing (210) surrounding a housing cavity (CC), wherein: a working volume (OPV) of the refractive fluid (250) is contained in the housing cavity (CC) and the controllable sound wave generating element (220) is arranged within the lens housing around an optical path (OPATH) passing through the working volume (OPV), wherein an axial direction of the TAG lens (170A - F) is defined as parallel to an optical axis (OA) of the optical path (OPATH); and the working volume (OPV) of the light-refracting fluid (250) to change its refractive index along the optical path (OPATH) in response to the application of a sound wave by the sound wave generating element (220) in accordance with how the TAG lens (170A - F) is controlled, is capable of providing a periodically modulated optical power variation for the TAG lens (170A - F) when a periodic drive signal is applied to the sound wave generating element (220); and the lens housing (210) comprises the following: a casing wall section (CWP) that generally extends along the axial direction, and first and second housing end sections (CEPt, CEPb) extending generally transversely to the axial direction, each housing end section (CEPt, CEPb) comprising a centrally located window configuration (WCFt, WCFb) comprising a window (214t, 214b) mounted along the optical path (OPATH) in a window mounting section (WMPt, WMPb) and a housing end termination section (CERt, CERb) that is at least partially aligned with and sealed to the housing wall section (CWP), where: Each window mounting section (WMPt, WMPb) has a total axial window mounting dimension (OWMDt, OWMDb) defined between two parallel window mounting boundary planes perpendicular to the optical axis (OPATH), which coincide with the most distant inner and outer surfaces of that window mounting section (WMPt, WMPb), respectively; and Each housing end section (CEPt, CEPb) further comprises a respective improved axial conformity section (ACPt, ACPb) which is coupled and thus sealed between its associated window mounting section (WMPt, WMPb) and housing end liner section (CERt, CERb) and holds its associated window mounting section (WMPt, WMPb) in place and is configured to improve an axial deflection amplitude of its associated window mounting section (WMPt, WMPb) relative to its associated housing end liner section (CERt, CERb) when the periodic drive signal is applied to the sound wave generating element (220), wherein: in each housing end section (CEPt, CEPb) its corresponding improved axial conformity section (ACPt, ACPb) comprises a first reduced thickness region (RTR1t, RTR1b) characterized by a reduced material thickness (RMT1t, RMT1b) along the axial direction which is at most 75% of the total axial window mounting dimension (OWMDt, OWMDb) of its associated window mounting section (WMPt, WMPb) and which extends around its associated window mounting section (WMPt, WMPb) over an angle of intersection of at least 270 degrees around the optical axis (OA).

Description

BACKGROUND Technical area

[0001] This disclosure relates to tunable acoustic gradient lenses and, in particular, to the application of tunable acoustic gradient lenses in variable focal length lens systems used for inspection and dimensional metrology. Description of the state of the art

[0002] Various types of variable focal length (VFL) optical systems can be used for observing and precision measuring surface heights and can be incorporated into a microscope and / or a precision machine vision inspection system, for example, as disclosed in U.S. Patent US 9,143,647 B2, which is hereby incorporated in its entirety by reference. In short, a VFL lens is capable of capturing multiple images at multiple focal lengths. One type of known VFL lens is a tunable sound gradient lens (“TAG” lens), which creates a lensing effect using sound waves in a fluid medium. The sound waves can be directed by applying an electric field with a TAG lens resonant frequency to a vibrating element (e.g., a vibrating element).A piezoelectric tube surrounding the fluid medium is used to generate a time-varying density and refractive index profile within the lens fluid, thereby modulating its optical power and, consequently, the focal length or effective focal point position of the visual system. A TAG lens can be used to modulate a focal point position at a resonant frequency of up to several hundred kHz, i.e., at high speed. Such a lens can be more fully understood by referring to the teachings in the article "High speed varifocal imaging with a tunable acoustic gradient index of refraction lens" (Optics Letters, Vol. 33, No. 18, September 15, 2008) and in U.S. patents US 8,194,307 B2, US 9,213,175 B2, and US 9,256,009 B2, all of which are hereby incorporated in full by reference. Tunable acoustic gradient index lenses and associated controllable signal generators are available, for example from TAG Optics, Inc., from Princeton, New Jersey.

[0003] Limitations in the optical performance (e.g., focal range) and / or operational stability of a TAG lens can correspondingly limit the performance of a system incorporating the TAG lens. Such limitations may be less critical for simple imaging applications (where the primary purpose is, for example, observation). However, in metrology systems (e.g., microscope systems, where a TAG lens is precisely calibrated to correlate a specific optical performance (or focal distance) with a specific phase of the resonance cycle), such limitations can be relatively critical with respect to the precision and range for performing specific inspection and dimensional metrology functions of the system. For such applications, a configuration that provides improvements in the optical performance (e.g., focal range) and / or operational stability of a TAG lens would be desirable. SUMMARY

[0004] This summary is provided to introduce, in a simplified form, a selection of concepts that are further described in detail below. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of protection of the claimed subject matter.

[0005] A tunable acoustic gradient lens (TAG lens) is created, comprising a controllable acoustic wave generator, a refractive fluid, and a lens housing surrounding a housing cavity. A working volume of the refractive fluid is contained within the housing cavity, and the controllable acoustic wave generator is arranged within the lens housing around an optical path traversing the working volume. An axial direction of the TAG lens is defined as parallel to an optical axis OA of the optical path.The working volume of the refractive fluid is capable of changing its refractive index along the optical path in response to the application of a sound wave by the sound wave generating element, in accordance with how the TAG lens is controlled to provide a periodically modulated variation in optical power to the TAG lens when a periodic drive signal is applied to the sound wave generating element. In various implementations, the TAG lens is included as part of a vision system, and the control of the TAG lens to provide a periodically modulated variation in optical power to the TAG lens accordingly provides a variation in focal distance for the vision system.

[0006] In various implementations, the lens housing wall section generally extends in the axial direction, and there are first and second housing end sections that generally extend transversely to the axial direction. Each housing end section includes a centrally located window configuration comprising a window mounted along the optical path in a window mounting section, and a housing end flange section that is at least partially aligned with and sealed to the housing wall section. Each window mounting section has an entire axial window mounting dimension (along the axial direction) defined between two parallel window mounting boundary planes that are perpendicular to the optical axis and that coincide with the farthest inner and outer surfaces of that window mounting section, respectively.According to the principles disclosed herein, each housing end section further comprises a respective enhanced axial conformance section that is coupled and thus sealed between its associated window mounting section and housing end frame section, and that holds its associated window mounting section in place and is configured to improve the axial deflection amplitude of its associated window mounting section relative to its associated housing end frame section when the periodic drive signal is applied to the sound wave generating element. In each housing end section, its respective enhanced axial conformance section comprises a first region of reduced thickness (which in some implementations, for example,(corresponding to an annular groove in a housing end section), characterized by a reduced material thickness along the axial direction, which is at most 75% of the total axial window mounting dimension of its associated window mounting section. The first region of reduced thickness generally extends around its associated window mounting section over a section angle of at least 270 degrees about the optical axis. In various implementations, the first region of reduced thickness may have a general annular shape and extend over a section angle in the range of 270 to 360 degrees. The inventors have found that such a configuration improves the focal area and / or operational stability (e.g.,The stability of the focal range and / or the stability of the resonant frequency associated with the periodic drive signal of the TAG lens is improved, thus maintaining the stability and precision of its optical performance and / or focal distance calibration relative to the phase of its periodic drive signal. All such improvements, however small, are critical for enhancing the utility and precision of TAG lens-based measurement systems.

[0007] In some implementations, the first area of ​​reduced thickness may be characterized by a reduced material thickness along the axial direction that is at most 65% or at most 55% (or less) of the total axial window bracket dimension of its associated window installation section.

[0008] In some implementations, the first reduced-thickness region may include a first recessed surface that is equal in area to or larger than the first reduced-thickness region and that is recessed along the axial direction relative to an adjacent surface of its associated housing end section, thus limiting the reduced material thickness of the first reduced-thickness region along the axial direction. The first recessed surface may include a surface portion of a groove formed in the material of a housing end section. In some implementations, the TAG lens has a generally cylindrical shape, and the groove formed in the housing end section material may have a general annular shape.

[0009] In various implementations, the first recessed surface of each housing end section can be located in either an outer or an inner surface of that housing end section. Similarly, in various implementations, a second recessed surface of each housing end section can be located in either an outer or an inner surface of that housing end section. In some implementations, if the first recessed surface is located in an inner surface, then the second recessed surface is located in an outer surface, or if the first recessed surface is located in an inner surface, then the second recessed surface is located in an outer surface. However, such implementations are merely examples and are not limiting.

[0010] In some implementations, in each housing end section, its associated housing end frame section includes sections that define a bearing surface plane that is nominally perpendicular to the optical axis, and all outer surfaces of its associated window mounting section are recessed along the axial direction relative to the bearing surface plane by a distance along the axial direction that is greater than the improved axial deflection amplitude of that associated window mounting section.

[0011] In some implementations, at least one housing end section may include its associated housing end-mount section containing a mounting surface around its periphery configured to receive a mounting element (e.g., a mounting clamp) that exerts a force on the mounting surface along a radial direction perpendicular to the optical axis. The at least one housing end section may further include a radial load isolation configuration comprising at least one radial load receiving channel or radial conformance bending element extending over a section angle of at least 270 degrees around the optical axis and located between its mounting surface and the first region of reduced thickness of its associated improved axial conformance section along the radial direction.In various implementations, the TAG lens can have a generally cylindrical shape, the first area of ​​reduced thickness can be an annular area, and the receiving channel for radial loading can have an annular groove formed in an outer end face of this at least one housing end section.

[0012] In some implementations, at least the improved axial conformity section and the window configuration for each housing end section are configured according to the various principles disclosed herein to provide a TAG lens resonant mode that includes axial displacement of the window mounting section relative to its associated housing end mounting section, wherein the resonant bandwidth of this resonant mode, as specified by the amplitude of the axial displacement of the window mounting section relative to its associated housing end mounting section, includes the frequency of the periodic drive signal applied to the sound wave generating element. Brief description of the multiple views of the drawings Fig. Figure 1 is a block diagram of an optical imaging section and a control system section of an imaging / inspection system that includes a TAG lens; Fig. Figure 2 is a diagram of a cross-section of a TAG lens containing known features that include a standing sound wave generated at resonance within it; Fig. Figure 3 is a diagram of a cross-section of a TAG lens with a first exemplary implementation of a lens housing, which includes a first exemplary implementation of the use of a section for improved axial conformity in each housing end section; Fig. Figure 4 is a diagram of a cross-section of a TAG lens with a second exemplary implementation of a lens housing, which includes a second exemplary implementation of the use of a section for improved axial conformity in each housing end section; Fig. Figure 5 is a diagram of cross-sections of a TAG lens with a third exemplary implementation of a lens housing, which includes a third exemplary implementation of the use of a section for improved axial conformity in combination with an isolation configuration for radial loading in each housing end section; and Fig. 6A and Fig. 6B are diagrams of an isometric and a top view of the in Fig. 5 TAG lenses shown, which contain a generic implementation of an external reservoir configuration. DETAILED DESCRIPTION

[0013] The description of the Fig. 1 and Fig. Section 2 provides a brief background on the various operating principles and applications of a TAG lens in a workpiece inspection system. To supplement this brief background with more in-depth explanations and understanding, various aspects of such operating principles and applications are described in greater detail in the references cited above and in U.S. patents US 9,930,243 B2; US 9,736,355 B1; and US 7,627,162 B2, all of which are hereby incorporated in full by reference.

[0014] Fig. Figure 1 is a block diagram of an imaging / inspection system 10, which includes an optical imaging system 105, a light source 130, a workpiece table 110, and a control system section 101. In various implementations, the imaging / inspection system 10 can be adapted to a machine vision host system or used as a standalone system and can be operated according to the principles disclosed herein and in the incorporated references. The imaging / inspection system 10, which includes the optical imaging system 105, the light source 130, and the workpiece table 110, can generally be controlled by the control system section 101 to image or inspect a workpiece 20.

[0015] The optical imaging system 105 includes an image detector 160 (e.g., a camera), one or more field lenses 150 (e.g., containing an interchangeable lens), and a TAG lens 170A. The control system section 101 may include system manager circuits / routines 125 that can control an input / output interface 139, and image manager circuits / routines 180. A host system or various individual display devices or input devices, or the like, may be connected to the input / output interface 139. In some implementations, the workpiece table 110 may include an (optional) motion control system that moves the workpiece relative to the optical imaging system 105.In such implementations, the system manager circuits and routines 125 may include a workpiece program generator and execution unit (not shown) that operates the motion control system and other features of the imaging / inspection system 10 to automatically inspect the workpiece 20, as disclosed in the incorporated references. As in . Fig. As shown in Figure 1, the imaging manager circuits / routines 180 contain or control an illumination control interface 132, a camera control interface 162, and a TAG lens control interface 172. The TAG lens control interface 172 may contain or be associated with a tag lens control unit (e.g., in a section of the imaging manager circuits / routines 180), which controls circuits and / or routines for controlling various image exposures synchronized with the periodic focal position modulation provided by the TAG lens 170A. In some implementations, the TAG lens control interface 172 and a tag lens control unit may be merged and / or indistinguishable. The lighting control interface 132 can, for example, control the selection, power, on / off switch and stroboscopic pulse time, if applicable, for corresponding lighting sources (e.g., the lighting source 130).In some implementations, the illumination control interface 132 may include an exposure (stroboscopic) timing unit or may otherwise provide stroboscopic timing signals (e.g., for the illumination source 130) so that it provides an image exposure stroboscopic timing synchronized with a desired phase time of the TAG lens focal position modulation. The camera control interface 162 may, for example, control the camera configuration, exposure time, data output, and the like, if applicable. In some implementations, the camera control interface 162 may include a timing unit so that the camera image exposure time is synchronized with a desired phase time of the TAG lens focal position modulation and / or an illumination time.Each of these components, as well as the additional components described below, can be interconnected by one or more data / control buses and / or application programming interfaces, or by direct connections between the different elements.

[0016] As described in more detail below, an optical imaging path OPATH (along the optical axis OA) comprises various optical components that convey the workpiece imaging light 155 from the workpiece 20 to the image detector 160. For example, the field lens 150, the TAG lens 170A, and the image detector 160 can all be arranged such that their optical axes are aligned on the same optical axis OA, which intersects the surface of the workpiece 20. However, it should be understood that this implementation is only exemplary and not limiting. More generally, the optical imaging path OPATH can include mirrors and / or other optical elements and can take any form that functions to image the workpiece 20 using an image detector (e.g., the image detector 160) according to known principles.In the implementation shown, the optical imaging path OPATH contains the TAG lens 170A and can be used to image and / or measure a surface of a workpiece 20 using one or more workpiece image exposures.

[0017] As briefly described above, the optical power of the TAG lens 170A changes continuously at a high frequency in response to the resonant drive signal (e.g., as input on a signal line 171 from a TAG lens control interface 172 of the control system section 101). The effective focal position EFP changes accordingly. In various implementations, the drive signal is a sinusoidal AC voltage signal at a resonant frequency of the operation of the TAG lens 170A. A focal length Df corresponding to an effective focal position EFP is available at a corresponding time, or "phase time," during the sinusoidal change in the optical power of the TAG lens 170A. The nominal or "mean" effective focal position can be considered to be the (fixed) focal length of the field lens 150 (e.g.,a lens) is, in combination with the TAG lens, in a state where its optical power is zero. The illumination source 130 or the image detector 160 can be "sampled" at a specific phase or "phase time" of the resonance cycle to obtain an image exposure focused at a corresponding effective focal point position or focal point distance. The source light 134 is reflected or passed on as the workpiece light 155, and the workpiece light used for imaging passes through the field lens 150 and the TAG lens 170A and is collected by the image detector 160 (e.g., a camera). A workpiece image exposure containing the image of the workpiece 20 is captured by the image detector 160 and output to a signal line 161 to the imaging manager circuitry / routines 180 (e.g., via a camera control interface 162).In various implementations, the image detector 160 can be a known charge-coupling element (CCD) image sensor or another form of camera and can receive an incident image IMG and can output a detected image DIMG, which has a predetermined signal shape, to the imaging manager circuit / routines 180.

[0018] Known contrast-based focal point analysis methods can be used to analyze the resulting image(s) and determine whether they are in focus, and / or can be used in the system manager circuits and routines 125 or the imaging manager circuits / routines 180 to adjust the stroboscopic phase time to provide an “auto-focus” operation that delivers a focused image of the workpiece 20. Alternatively or additionally, such contrast-based focal point analysis methods can be used to identify an image with the best focal point from a group of images acquired at a corresponding group of known phase times and to output this phase time value with the “best focal point”.Z-height calibration data (at the effective focal point position) can be used, which refers to corresponding Z-heights or effective focal point positions at corresponding phase times with "best focal point". Thus, the surface height coordinate of an imaged surface section of a workpiece 20 can be determined based on the phase time assigned to its image with "best focal point". Therefore, the optical imaging system 105 and / or the imaging / inspection system 10 can be used to measure the workpiece 20 by scanning it or to measure the profile, if desired. Various aspects of such measurement processes are described in more detail in the included references.

[0019] Based on the foregoing description, with regard to the optical performance and / or focal range and / or operational stability (e.g., the stability of the focal range and / or the stability of the resonant frequency associated with the periodic drive signal) of a TAG lens, it is understood that improved performance and / or stability of any of these characteristics can enhance the overall performance of an imaging system or other system incorporating the TAG lens and / or increase precision when used in a metrology system. A TAG lens configuration exhibiting specific known features is described below with reference to Fig. 2 described in more detail. Configurations according to the principles disclosed herein, which provide improvements in the performance and / or stability of a TAG lens, are described below with reference to the Fig. 3 to 6 are described in more detail.

[0020] Fig. Figure 2 is a diagram of a cross-sectional view of a TAG lens 170B, which incorporates special known features. The TAG lens 170B includes a lens housing 210, which comprises a housing end section 210A (also referred to as a housing end section CEPt) and a combined housing wall / housing end section 210B. As shown in Figure 2, the housing wall / housing end section 210A is a cross-sectional view of a TAG lens 170B, which incorporates special known features. Fig. As shown in Figure 2, the combined housing wall / housing end section 210B comprises a housing end section CEPb and a housing wall section CWP. The lens housing 210 surrounds the housing cavity CC. The TAG lens 170B further includes a controllable sound wave generating element 220 and a refractive fluid 250. As shown in Fig. Figure 2 shows that a housing cavity CC of the lens housing 210 contains a working volume OPV of the refractive fluid 250, and the sound wave generating element 220 (e.g., a piezoelectric vibrator) is arranged inside the lens housing 210 around an optical path OPATH that passes through the working volume OPV. In various implementations (e.g., as shown here), the lens housing 210 can be a hollow cylindrical housing, and the controllable sound wave generating element 220 can be a hollow cylindrical piezoelectric vibrator installed on the interior of the lens housing 210.

[0021] According to a convention used here, the suffix "t" generally indicates a feature of the "upper" housing end section CEPt, and the suffix "b" generally indicates a feature of the "lower" housing end section CEPb. It should be understood that the use of "upper" and "lower" is only for convenience, to distinguish one housing end section from another in the various descriptions of figures. Generally, a TAG lens can be used in an inverted or rotated position, if desired.

[0022] In various alternative implementations, the lens housing 210 can have other shapes (e.g., a hollow hexagonal shape or a square shape, etc.). In various implementations, the controllable sound wave generating element 220 can be supported by spacers 260, 261, and 262 (e.g., O-rings used only for mechanical support, made of an elastomer, etc.). In various implementations, one or more spacers can be arranged between an outer circumferential surface 230 of the controllable sound wave generating element 220 and the inner circumferential surface of a cavity wall 215 of the lens housing 210 (e.g., to form a space SP1). Similarly, one or more spacers 261 can be arranged between a top surface 231 of the controllable sound wave generating element 220 and an upper inner surface 217t of the lens housing 210 (e.g.,to form an intermediate space SP2), and one or more spacers 262 can be arranged between a bottom surface 232 of the controllable sound wave generating element 220 and a lower inner surface 217b of the lens housing 210 (e.g. to form an intermediate space SP3).

[0023] In various implementations, the controllable sound wave generating element 220 vibrates in a radial direction due to a control signal (e.g., an alternating voltage applied between the outer circumferential surface 230 and the inner circumferential surface 240). In various implementations, the control signal is supplied via a signal line (e.g., the signal line 171 of Fig. 1, as provided by the TAG lens control interface 172 of the control system section 101) and applied to the sound wave generating element 220 via the electrical connecting element 225.

[0024] In various implementations, the control signal (which includes, for example, an alternating voltage) provided on signal line 171 can be tuned to a resonant frequency that produces a standing sound wave W in the refractive fluid 250 on the inside of the controllable sound wave generating element 220 (i.e., within the section of the housing cavity enclosed by the inner circumferential surface 240). In such a case, when the controllable sound wave generating element 220 is vibrated as indicated by the representative vibration arrows VA, a standing sound wave W is generated in the refractive fluid 250 (i.e., concentric circular wave regions are created where the refractive index increases and decreases). It is understood that the standing sound wave W produces a density gradient that provides a refractive index distribution approximately corresponding to the standing sound wave W.The middle section of this refractive index distribution, represented as the optical path OPATH between the vertical dashed lines, can be used for imaging.

[0025] As mentioned above, the housing cavity CC (as formed, for example, by the inner circumferential surface of the cavity wall 215 and the inner surfaces 217t and 217b) is filled with the refractive fluid 250. In various implementations, the refractive fluid 250 can be added to the housing cavity CC through one or more inlet / outlet openings (which, for example, include an inlet / outlet opening 211), which are then sealed. In various implementations, under desired operating conditions, the entire controllable sound wave generating element 220 is immersed in the refractive fluid 250, so that the cavity within the hollow cylindrical controllable sound wave generating element 220 (i.e., as surrounded by the inner circumferential surface 240) is filled with the refractive fluid 250.The vertical slots or channels 219 and radial slots or channels 218 in the lens housing 210 allow the refractive fluid 250 to flow past the various spacers (e.g., O-rings) to surround the outer circumferential surface 230 of the sound wave generating element 220 during and after filling. In contrast to the space SP1, which extends around the entire outer circumferential surface of the sound wave generating element 220, the radial and vertical channels 218 and 219 are discrete channels (e.g., horizontal and vertical slots formed by drilling or other processes in the lens housing 210). The light-refracting fluid 250 can flow from the cavity within the inner circumferential surface 240 into the radial channel(s) 218 ​​and through the spaces SP (e.g., the spaces SP1 and SP3) formed by the spacers (e.g.,The spacers 260 and 262) are produced and flow into the vertical channel(s) 219. In this way, the refractive fluid 250 can also fill the spaces SP1, SP2, and SP3 between the sound wave generating element 220 and the inner circumferential surface of the cavity wall 215 and the upper and lower inner surfaces 217t and 217b of the housing cavity CC of the lens housing 219, in order to surround the exterior of the sound wave generating element 220. The TAG lens 170B also includes upper and lower windows 214t and 214b, which are arranged on and sealed against the upper and lower sections of the housing cavity CC, respectively. The optical path OPATH, passing through the center of the TAG lens 170B (e.g. centered along the optical axis OA), passes through the upper and lower windows 214t and 214b.

[0026] It is clear that the resonant frequency briefly described above is a property of the overall system. As more precisely described in the concurrently pending and jointly assigned U.S. patent application US 2019 / 0369300A1, application no. 16 / 000,319, entitled “External Reservoir Configuration For Tunable Acoustic Gradient Lens,” filed on June 5, 2018 (hereinafter the '319 application'), which is hereby incorporated in full by reference, the resonant frequency may be sensitive to variations in factors such as temperature and / or pressure and / or mechanical stresses. The lens effect characteristics of the resulting standing sound wave W may similarly be sensitive to variations in such factors. Therefore, the TAG lens 170B may be affected by the operating condition used to obtain the aforementioned calibration data (the data determining the effective focal point position EFP or optical power vs.Phase-time values ​​are used to create and vary, and as a result, height measurement errors may occur. The resulting errors may be small, but they are significant for precision measurement applications. The various principles and configurations disclosed in the 319 application are aimed both at reducing the variations of the aforementioned control factors and at reducing variations due to the motion and / or inadequacy of a previously known and used type of compressible element IGV / ICE or the like.

[0027] Regarding the compressible element IGV / ICE, a configuration in Fig. 2 is represented by the dashed outlines, which represent an approximate cross-section of an annular compressible element intended to be held in a corresponding annular recess. The annular compressible element IGV / ICE has been known to be a desired gas volume or a closed-cell foam element or the like. It is noted that the annular recess, shown to correspond to the annular compressible element IGV / ICE, was known to have dimensions based only on those considered desirable for the compressible element IGV / ICE. In general, known annular compressible elements IGV / ICE have been inadequate for their intended purpose, as disclosed in the 319 application, and therefore their dimensions have not had a specific range of values ​​or adjustment.Accordingly, the ring-shaped recess, which is shown to correspond to the ring-shaped compressible element IGV / ICE, is as shown in . Fig. Figure 2 is shown only as a schematic representation for illustrative purposes (e.g., as explained in the '319 application). Similarly, the dimensions of the recess shown in surface 216t of the housing end section CEPt, which is shown in Fig. Figure 2 shows no specific value range or adjustment. One purpose of such a recess was to allow the fluid to fill the housing cavity CC more easily and / or cleanly through the inlet / outlet opening 211. Accordingly, the recess shown, located in the surface 216t of the housing end section CEPt in Fig. Figure 2 is only a schematic representation.

[0028] In contrast to the various ring-shaped recesses found further down in the Fig. As shown in Figures 3-6B, the dimensions of the various recesses shown are not specified or significant in the sense disclosed herein, and their function is not directed towards influencing the axial conformity of the housing end section CEPt (210A). For the avoidance of confusion, it is to be understood, as described elsewhere herein, that the individual radial slots 218, shown in the dashed outline in Fig. Figure 2 shows thin radial flow channels under the spacer 262 and no annular recess. The desirability of providing improved axial conformity of the housing end section CEPt was unknown prior to its disclosure here, and the dimensions and placement of recesses in CEP end sections from the prior art are merely incidental and not significant in this respect.

[0029] As described in the 319 application, in order to achieve an improved configuration that also eliminates and renders redundant the annular compressible element IGV / ICE and its corresponding annular recess, the housing cavity CC can be replaced by a flow channel FLC (e.g., as in the Fig. 3, Fig. 4 and Fig. 4 shown here) to a configuration of an external reservoir 280 (e.g. as in the Fig. 6A and Fig. 6B shown here), which contains a deformable external fluid reservoir containing a reserve volume of the refractive fluid 250. The flow channel FLC allows the refractive fluid 250 to flow back and forth between the housing cavity CC and the deformable external fluid reservoir in accordance with the expansion and contraction of the refractive fluid (e.g., due to temperature changes), which has particular advantages for addressing various problems as described in the '319 application.

[0030] As below with reference to the Fig. As described in more detail in Figure 3-6B, several principles aimed at improving the optical performance of a TAG lens are revealed here. Regarding optical performance, as described above, the optical lensing effect of a TAG lens 170 can be achieved by the cyclic compression of the refractive fluid 250 (e.g., silicone oil) by the vibrating motion of the sound wave generating element 220 (e.g., a piezoelectric cylinder). When the refractive fluid 250 experiences a change in pressure, there is a corresponding change in the refractive index of the refractive fluid 250, which produces a change in the optical performance of the TAG lens 170 (e.g., in some implementations, most importantly near the mean optical axis OA of the TAG lens 170).In various implementations, the optical performance can be proportional to the integral of the compression of the refractive fluid 250 along the length of the optical axis OA, so that higher average peak compression of the refractive fluid 250 along the full length of the optical axis OA of the lens can lead to higher / improved optical performance.

[0031] As a brief overview of the configurations of Fig. In various implementations, 3-6B allows for greater compression of the refractive fluid 250 by causing the sound wave generating element 220 to vibrate with a larger mean displacement along its entire length along the optical axis OA. The lens housing 210 acts to contain the refractive fluid 250, to keep the sound wave generating element 220 aligned with the optical axis OA, and to provide a structure for mounting the TAG lens 170 in an optical system (in which, for example, the lens housing 210, and in particular the housing end sections CEP, are clamped or otherwise attached to support structures or other components in an optical system, etc.). The sound wave generating element 220 is connected to the lens housing 210 by the light-refracting fluid 250 as well as the spacers 260, 261 and 262 (e.g. O-rings used for mechanical bearing, made of an elastomer, etc.).), which are positioned along the side and upper and lower edges of the sound wave generating element 220, are mechanically coupled. In various implementations, in order for the sound wave generating element 220 to achieve large displacements, it may be desirable for the lens housing 210 to vibrate and / or deflect in a mode that assists the movement of the sound wave generating element 220 as it compresses the refractive fluid 250 along the optical axis OA.

[0032] As below with reference to the Fig. As described in more detail in 3-6B, the inventors have determined that for a central section (e.g., a window configuration WCF) of one or both housing end section(s) CEP, it is desirable to deflect slightly along the axial direction in response to the movement of the sound wave generating element 220 and the associated fluid pressures, so that the window configuration WCF, instead of acting as a rigid resistance to the movement of the sound wave generating element 220, can move slightly (e.g., with an improved axial deflection on the order of a few tens to a few hundred nanometers) in conjunction with the movement of the sound wave generating element 220 (e.g., to enhance the movement / vibration and increase the overall amplitude of the movement / vibration of the sound wave generating element 220).As described in more detail below, in various implementations such movement and the corresponding effects can be achieved by incorporating an improved axial conformity section (ACP) into one or preferably both housing end sections (CEPt and CEPb) (e.g., as in ). Fig. 3 and Fig. 4) can be activated / enlarged / improved. As mentioned above, various implementations may also include a configuration of an external reservoir (e.g., in accordance with the lessons of the '319 filing) (e.g., as in the Fig. 6A and Fig. 6B shown).

[0033] With reference to any of the various configurations described here (e.g., with reference to any of the TAG lenses 170C-170F of the Fig. 3-6B) In some implementations, it may be desirable to match the mass and stiffness of one or both window configurations WCF and their associated improved axial conformance section(s) ACP with the rest of the overall TAG lens system so that the system naturally supports the movement / vibration of the sound wave generating element 220 at a frequency (or frequencies) used to drive the TAG lens 170. In various implementations, the window configuration WCF and / or the axial conformance section ACP supporting it may be configured to have a resonant frequency that responds at least partially to the operating frequency of the TAG lens 170. With regard to such considerations, it may be desirable in various implementations to specify a size or mass of the window configuration WCF (which, for example,to tune / utilize the relative size of the window 214, which interacts with the configuration stiffness of the axial conformance section ACP to achieve a desirable deflection / vibration amplitude of the window configuration WCF along the axial direction (e.g. for a given drive frequency).In various implementations, according to a design method, at least the Improved Axial Conformity Section (ACP) and the Window Configuration Function (WCF) for each housing end section (CEP) are configured to provide a resonant mode of the TAG lens that includes axial displacement of the window mounting section relative to its associated housing end section. The resonant bandwidth of this mode, as specified by the amplitude of the axial displacement of the window mounting section relative to its associated housing end section, includes the frequency of the periodic drive signal applied to the sound wave generating element. In general, the disclosed implementations can desirablely provide an efficient resonant system that achieves a high mean displacement / movement / vibration of the sound wave generating element 220 (e.g., with minimal input electrical energy, etc.).

[0034] Fig. Figure 3 is a diagram of a cross-section of a TAG lens 170C with a first exemplary implementation of a lens housing 210, which includes a first exemplary implementation of the use of an improved axial conformance section (ACP) in each housing end section (CEP). It is to be understood that elements that are in Fig. 3 and Fig. 2. Items that are similarly numbered or designated may have an analogous or identical function and / or configuration and may be understood by analogy with the preceding description, unless otherwise indicated by the description or context. Therefore, only significant differences and / or new features are precisely described below. This numbering scheme for indicating elements that have an analogous function and / or configuration is also applied to the following Fig. 4-6B applied. In some cases, reference marks for obviously similar or identical elements in later figures are omitted to avoid visual clutter and to more clearly indicate new or different elements introduced in those later figures. Such similar or identical elements may be recognized in the various figures and may be understood by analogy to the earlier description, unless otherwise indicated by the description or context.

[0035] Similar to the TAG lenses 170A and 170B, the TAG lens 170C from Fig. 3 the controllable sound wave generating element 220 and the refractive fluid 250, wherein the lens housing 210 surrounds the housing cavity CC. The working volume OPV of the refractive fluid 250 is contained within the housing cavity CC, and the controllable sound wave generating element 220 is arranged within the lens housing 210 around the optical path OPATH, which passes through the working volume OPV. The working volume OPV of the refractive fluid 250 is capable of changing its refractive index along the optical path OPATH in response to the application of a sound wave by the sound wave generating element 220, in accordance with how the TAG lens 170C is controlled, to provide a periodically modulated optical power variation for the TAG lens 170C when a periodic drive signal is applied to the sound wave generating element.As described above, in various implementations the TAG lens 170C can be included as part of a vision system 10, and the control of the TAG lens 170C to provide a periodically modulated variation of the optical power for the TAG lens 170C accordingly provides a focal distance variation for the vision system 10.

[0036] As described in more detail below, a primary difference from the TAG lens 170B is... Fig. 2, that the TAG lens 170C from Fig. 3 includes an improved axial conformance section ACPb in the housing end section CEPb and an improved axial conformance section ACPt in the housing end section CEPt, as described in more detail below. The TAG lenses shown here may have a general cylindrical shape, and many of the features briefly described below may be understood as being represented as cross-sections of partially or fully annular regions, with similarly marked identifiers to the left and right of a TAG lens shown (e.g., CERt in Fig. 3) are understood to refer to diametrically opposed sections of the same “ring-shaped” area or feature.

[0037] The lens housing comprises a housing wall section CWP, which generally extends along the axial direction, and upper and lower housing end sections CEPt and CEPb, which generally extend transversely to the axial direction. The upper housing end section CEPt comprises a centrally located window configuration WCFt, which includes a window 214t mounted along the optical path OPATH in a window mounting section WMPt (corresponding approximately to the specified bracket), and a housing end termination section CERt (corresponding approximately to the specified brackets) that is at least partially aligned with and sealed to the housing wall section CWP, e.g., by fastening and sealing at the intermediate junction according to known methods.Similarly, the lower housing end section CEPb comprises a centrally located window configuration WCFb, which includes a window 214b fitted along the optical path OPATH in a window mounting section WMPb (corresponding approximately to the bracket shown), and a housing end termination section CERb (corresponding approximately to the brackets shown) that is at least partially aligned with and sealed to the housing wall section CWP, e.g. by being integrally formed with the housing wall section CWP and connected to it at the dashed lines 299.

[0038] Each window mounting section WMPt (or WMPb) has a total axial window mounting dimension OWMDt (or OWMDb) defined between two parallel window mounting boundary planes perpendicular to the optical axis, each coinciding with the furthest inner and outer surfaces of that window mounting section.

[0039] The upper housing end section CEPt further comprises a corresponding improved axial conformity section ACPt (corresponding approximately to the brackets shown), which is coupled between and sealed with its associated window mounting section WMPt and housing end liner section CERt (e.g., by being integrally formed with them, as shown), holds its associated window mounting section WMPt in place, and is configured to improve the deflection amplitude in the axial direction of its associated window mounting section WMPt relative to its associated housing end liner section CERt when the periodic drive signal is applied to the sound wave generating element 220.Similarly, the lower housing end section CEPb further comprises a corresponding improved axial conformity section ACPb (corresponding approximately to the brackets shown) which is coupled between and sealed with its associated window mounting section WMPb and housing end enclosure section CERb (e.g., by being integrally formed with them, as shown), holds its associated window mounting section WMPb in place, and is configured to improve the axial deflection amplitude of its associated window mounting section WMPb relative to its associated housing end enclosure section CERb when the periodic drive signal is applied to the sound wave generating element 220.

[0040] According to the principles disclosed herein, in each housing end section CEPt (or CEPb), its corresponding improved axial conformity section ACPt (or ACPb) comprises a first reduced-thickness region RTR1t (or RTR1b) characterized by a reduced material thickness RMT1t (or RMT1b) along the axial direction, which is at most 75% of the total axial window mounting dimension OWMDt (or OWMDb) of its associated window mounting section WMPt (or WMPb), and which extends around its associated window mounting section over an angle of intersection of at least 270 degrees about the optical axis (as shown, for example, more clearly in Figures 6A and 6B). Generally, for the best optical performance of a TAG lens, it is preferable for an improved axial conformity section to have axial symmetry and to intersect at an angle of 360 degrees. Due to practical considerations (e.g.,However, due to connecting elements and / or installation considerations, etc., this may not be possible in all implementations. In such implementations, an "incomplete" or compromised section for improved axial conformity that does not extend over a full 360 degrees may still provide some of the benefits described here.

[0041] It may be desirable for the window mounting sections to be relatively thick (e.g., 8 millimeters or more) across all axial window mounting dimensions OWMDt and OWMDb to provide a relatively rigid and protective support for the fragile windows 214t and 214b and their associated seals on the window mounting sections WMPt and WMPb. If an improved axial conformity section is included in each housing end section CEPt and CEPb, the inventors have determined that improved operation of the TAG lens can be obtained if the reduced material thickness RMT1t (or RMT1b) is reduced to at most 75% of the total axial window mounting dimension OWMDt (or OWMDb). In some implementations, it may be more advantageous if the reduced material thickness RMT1t (or RMT1b) is reduced to a maximum of 65% or a maximum of 55% of the total axial window bracket dimension OWMDt (or OWMDb).This can be influenced, for example, by the width and / or shape of the first reduced-thickness region RTR1t (or RTR1b), the presence of more than one axial thickness-reducing feature or groove in the improved axial conformance section ACPt (or ACPb), and so on. It is understood that a TAG lens operates at a frequency of several tens or several hundred kHz, and a relatively stiff and stable lens structure at such frequencies is both necessary and desirable. It is understood that "improved conformance" is thus a relative term intended to be associated with improving the axial deflection amplitude of the window mounting sections WMPt and WMPb on the order of several tens to several hundred nanometers at the TAG lens operating frequency (compared to previously known TAG lens structures) according to the principles disclosed and claimed herein.

[0042] In the Fig. In the implementation shown in Figure 3, each housing end section CEPt (or CEPb) comprises a first recessed surface RS1t (or RS1b) that is equal in area to or larger than its corresponding first reduced-thickness area and is recessed along the axial direction relative to an adjacent surface of its associated housing end section CEPt (or CEPb), and that limits the reduced material thickness of its corresponding first reduced-thickness area RTR1t (or RTR1b) along the axial direction. Fig. In the specific implementation shown in Figure 3, the first recessed surface RS1t (RS1b) is a planar surface parallel to the opposite surface 216t (217b), and is therefore co-surface with its corresponding first region of reduced thickness. It is understood that in other embodiments, the first recessed surface (e.g., analogous to RS1t or RS1b) may comprise a curved or chamfered surface, if desired. In such a case, the first recessed surface may be larger than the corresponding first region of reduced thickness, with only the deeper portions of the first recessed surface being able to satisfy the condition requiring that its corresponding first region of reduced thickness has a thickness that is at most 75% of the associated total axial window bracket dimension.Furthermore, it should be understood that, depending on the shape or profile of the first recessed surface, different sections of the first reduced-thickness area may have different material thicknesses. It is understood that, provided that the different material thicknesses of any such sections are at most 75% of the associated total axial window support dimension (e.g., the total axial window support dimension OWMDt or OWMDb), then such sections meet the criteria outlined above, which relate to the definition and requirements of an improved axial conformity section ACPt or ACPb according to the principles disclosed herein.

[0043] In the Fig. In the implementation shown in Figure 3, the housing end section CEPt (or CEPb) comprises a window mounting section WMPt (or WMPb), a housing end rim section CERt (or CERb), and an improved axial conformance section ACPt (or ACPb), all formed in a single continuous piece of material, with the first recessed surface RS1t (or RS1b) comprising a surface portion of a groove formed in the single continuous piece of material. In the implementation shown, the TAG lens 170C can have a generally cylindrical shape (e.g., as in the Fig. 6A and Fig. 6B), and the groove formed in the single continuous piece of material may be an annular groove (extending, for example, around all or most of 360 degrees). However, it is understood that in various other implementations of any configuration according to the principles disclosed herein, the different elements of a CEPt (or CEPb) housing end section may be formed as individual elements and joined by weld, braze, or other known methods to form a functional housing end section, if desired. In the Fig. In the implementation shown in Figure 3, the first recessed surface RS1t is located in the inner surface 217t of the housing end section CEPt, and the first recessed surface RS1b is located in the outer surface 216b of the housing end section CEPb. However, such a configuration is only exemplary and not limiting. More generally, a first recessed surface can be located in either an inner or an outer surface in a housing end section.

[0044] As in Fig. Figure 3 shows that in various implementations, a TAG lens 170 (e.g., 170C) can be mounted in an optical system, wherein the lens housing 210 abuts other components of the optical system at the lower and / or upper ends of the lens housing 210 on a bearing surface plane ASP of the housing end section CEPt and / or CEPb to provide a specified or known gap along the axial direction for optical design purposes. A bearing surface plane ASP is also shown in the Fig. 6A and Fig. Figure 6B shows that, in accordance with principles disclosed herein, all outer surfaces of a window mounting section WMPt or WMPb of an associated window configuration WCFt or WCFb can be recessed along the axial direction relative to the bearing surface plane ASP by a distance along the axial direction greater than the amplitude of the enhanced axial deflection of that window mounting section. Such a configuration allows the window configuration WCFt or WCFb to move / vibrate / deflection (e.g., in resonance with the sound wave generating element 220) relative to the housing end-mount section CERt or CERb without contacting any mating surfaces that may adjoin the bearing surface plane ASP.

[0045] As in Fig. Figure 3 shows that a TAG lens 170 (e.g., 170C) can contain a flow channel FLC that allows the refractive fluid 250 to flow into a configuration of an external reservoir (e.g., the configuration of the external reservoir 280, as shown in the Fig. 6A and Fig. (shown in 6B) flows back and forth in a sealed system, which has advantages for addressing specific problems, as described in the '319 application included above. In the example implementation of Fig. 3. The illustrated flow channel FLC comprises a tube TB that may extend between the lens housing 210C (which extends, for example, into a reservoir exchange channel REC) and an external reservoir configuration, and through which the refractive fluid 250 can flow back and forth between the housing cavity CC and the external reservoir configuration. One or more sealing elements SL (e.g., sealing rings) may be included (e.g., arranged around the tube TB and to seal the connection between the lens housing 210 and the external reservoir configuration) to ensure the sealed containment of the refractive fluid 250. Other aspects associated with the flow channel FLC and an external reservoir configuration can be understood by reference to the 319 application.

[0046] Fig. Figure 4 is a diagram of a cross-section of a TAG lens 170D with a second exemplary implementation of a lens housing 210, which includes a second exemplary implementation of the use of an improved axial conformity section ACPt in the housing end section CEPt. The various features of the TAG lens 170D, which are described above in the TAG lens configurations (e.g., in Fig. 2 and Fig. 3) items that are similarly numbered or illustrated may be understood as similar or analogous to their counterparts described above, unless otherwise stated below.

[0047] As in Fig. As shown in Figure 4, the improved axial conformance section ACPt in the housing end section CEPt further includes a second recessed surface RS2t located in an outer surface 216t of the housing end section CEPt. The second recessed surface RS2t is recessed along the axial direction relative to an adjacent surface (e.g., surface 216t) of its associated housing end section and extends around its associated window mounting section WMPt at an angle of intersection of at least 270 degrees about the optical axis. In some implementations, it may be desirable for both the first and second recessed surfaces RS1t and RS2t to extend at an angle of intersection of 360 degrees about the optical axis to provide the best possible aberration-free optical performance.

[0048] In the Fig. In the implementation shown in Figure 4, the second recessed surface RS2t is configured such that it is aligned with a portion of the first recessed surface RS1t along the axial direction, and the second recessed surface RS2t limits the reduced material thickness of a portion of the first reduced-thickness region RTR1t along the axial direction (e.g., the portion that is in Fig. (3 shown dimension SEP). Thus, it can be understood that one section of the first reduced-thickness region RTR1t has a material thickness RMT1t that is at most 75% of the total axial window mount dimension OWMDt, and another section of the first reduced-thickness region RTR1t has a material thickness SEP that is less than the material thickness RMT1t. In general terms, it can be understood that such a configuration allows more design freedom for configuring the improved axial conformance section. For example, the implementation shown further increases the axial conformance of the improved axial conformance section ACPt of the TAG lens 170D relative to the improved axial conformance section ACPt of the TAG lens 170C, which is shown in Fig. Figure 3 shows this. It also changes the location of the neutral bending axis of the improved axial conformity section ACPt of the TAG lens 170D so that it is aligned closer to the center of mass of its associated window mounting section WMPt, which can be useful for reducing undesirable asymmetric (e.g., torsional) resonance mode shapes or the like. The in Fig. The implementation shown in Figure 4 is merely exemplary and not limiting. In other implementations, a second recessed surface can be configured analogously to the second recessed surface RS2t sp, such that it is fully aligned with the first recessed surface RS1t along the axial direction (so that its corresponding reduced material thickness is everywhere equal to dimension SEP), or it can be configured so that it is not aligned with any part of the first recessed surface RS1t along the axial direction. In the latter configuration, the separation distance SEP can be defined as the dimension or distance along the axial direction between the first and second planes, which are perpendicular to the optical axis OA and which, respectively, coincide with the most distant recessed sections of the first and second recessed surfaces.In some such configurations, the inventors have determined that it may be advantageous if the separation distance SEP is at most 55% of the total axial window mounting dimension OWMDt of the associated window installation section WMPt.

[0049] Fig. Figure 4 shows an installation area MSt that extends around the periphery of the housing end section CEPt on its associated housing end enclosing section CERt (except in the vicinity of the electrical connecting element 225 and its associated cover). Fig. Figure 4 also shows a mounting surface MSb that extends around the periphery of the housing end section CEPb on its associated housing end cap section CERb. In various implementations, a TAG lens may include one or both of these mounting surfaces. The mounting surface MSt (or MSb) may be configured to accommodate a mounting element that exerts a force on the mounting surface MSt (or MSb) along the radial direction (e.g., a compression mounting clip coupled to the mounting surface). It is understood that the force exerted by such a mounting element may stress or deform the housing end cap section CERt (or CERb) or the entire housing end section CEPt (or CEPb) in a manner that differs from the system calibration conditions, is unstable over time, and / or changes due to variations in operating temperature, and the like.Such instability is detectable in the resulting optical measurements (e.g. measurement deviation in the micrometer range) when a TAG lens is used in a precision measurement system.

[0050] It is to be understood that, although the second recessed surface RS2t is only in the upper housing end section CEPt in Fig. As shown in Figure 4, this implementation is only exemplary and not limiting. In various implementations, the first recessed surface of each housing end section can be located in either an outer or an inner surface of that housing end section. In various implementations, a second recessed surface of each housing end section can be located in either an outer or an inner surface of that housing end section. In some implementations, if the first recessed surface is located in an inner surface, then the second recessed surface is located in an outer surface, or if the first recessed surface is located in an inner surface, then the second recessed surface is located in an outer surface.These and other implementations, which include additional recessed surfaces in an improved axial conformity (ACP) section, are possible according to the principles disclosed and claimed herein.

[0051] The inventors have determined that, in addition to its function in the improved axial conformity section ACPt, the second recessed surface RS2t, located in an outer surface 216t of the housing end section CEPt, as shown in Fig. As shown in Figure 4, it can have a second function, acting as a radial load isolation configuration RSIC, located along the radial direction between the housing end-mount section CERt (which contains the mounting surface MSt) and the first reduced-thickness area RTR1t of the improved axial conformity section ACPt. According to one type of explanation or description, the groove or channel associated with the second recessed surface RS2t can be considered a radial load receiving channel RSAC, which allows a very small load (e.g.,Radial deflections or “rolling” of the adjacent housing end section CERt are at least partially absorbed or isolated, so that the load that would otherwise be transferred to stress or distort the relatively conformal Improved Axial Conformity Section ACPt, or other structures of the housing end section CEPt that are radially within the radial load receiving channel RSAC, is significantly reduced. This results in more stable operation of the TAG Lens 170D and is synergistic with the use of Improved Axial Conformity Sections ACP as disclosed here.In summary, according to an alternative description of the TAG lens 170D, which highlights the isolation configuration for radial load RISC, in one implementation the TAG lens 170D comprises a generally cylindrical shape, and its first area of ​​reduced thickness RTR1t can be an annular area, and it includes an isolation configuration for radial load RSIC located along the radial direction between the housing end framing section CERt and the first area of ​​reduced thickness RTR1t of the improved axial conformity section ACPt.In particular, in the implementation shown, the isolation configuration for radial load RSIC includes the receiving channel for radial load RSAC, which is an annular groove (corresponding to the second recessed surface RS2t) formed in an outer surface 216t of the housing end section CEPt and located along the radial direction between the housing end enclosing section CERt and the first reduced thickness area RTR1t of the improved axial conformity section ACPt.

[0052] Based on the above brief description and / or explanation, it can be seen that the isolation configuration for radial load RSIC, which is described in Fig. The configuration shown in section 4 is only exemplary and not limiting. The isolation configuration for radial loading RSIC, which is shown in Fig. As shown in Figure 4, the radial isolation configuration is located along the radial direction between the housing end-mount section CERt and the first reduced-thickness region RTR1t of the improved axial conformance section ACPt. However, for a TAG lens such as those disclosed here, which includes a mounting surface MS as briefly described above, a radial load isolation configuration RSIC can more generally be located in a housing end-mount section CEP at any desired location along the radial direction between its mounting surface MS and the first reduced-thickness region RTR1 of its improved axial conformance section ACP. In various implementations, a housing end-mount section containing a mounting surface MS around its periphery (e.g.,(as briefly described above), comprising a radial load isolation configuration RISC, which includes at least one radial load receiving channel RSAC or radial conformance bending element RCBE (described further below) extending over a section angle of at least 270 degrees about the optical axis OA and extending along the radial direction between its mounting surface MS and the first reduced-thickness region RTR1 of its associated enhanced axial conformance section ACP. An alternative radial load isolation configuration conforming to the description briefly described above is disclosed below.

[0053] Fig. Figure 5 is a diagram of cross-sections of a TAG lens 170E with a third exemplary implementation of a lens housing 210, which includes a third exemplary implementation of the use of an improved axial conformance section (ACP) in each housing end section (CEP) in combination with a radial load isolation configuration (RISC) that can be used in one or both housing end sections (CEP). The majority of the elements and features in the housing end sections (CEPt) and (CEPb) shown in Figure 5 are Fig. The 5 shown are similar to those in Fig. The four shown examples can be understood similarly. Therefore, only the significant differences are described below, which are shown in the examples shown. Fig. The 5 shown isolation configurations for radial loading are assigned to RISC.

[0054] As in Fig. Figure 5 shows that the isolation configuration for radial loading RISC comprises a radial loading isolation channel RSAC and a radial conformance bending element RCBE, each of which is to be understood as extending over a section angle of at least 270 degrees around the optical axis. It is to be understood that in some implementations the radial conformance bending element RCBE may comprise a continuous section around the section angle, or in other implementations it may comprise a group of sections RCBE' that extend around the section angle as a group (e.g., as in the Fig. 6A and Fig. (shown in Figure 6B). The radial load isolation channel RSAC and / or the radial conformance bending element RCBE are each located in a housing end section CEPt (or CEPb) between the mounting surface MS and the first reduced-thickness region of its associated improved axial conformance section ACPt (or ACPb) along the radial direction. In the implementation shown, the TAG lens 170E can have a generally cylindrical shape, and its first reduced-thickness regions RTR1t and RTR1b can be annular regions, and the radial load reception channel RASC can include an annular groove formed in an outer surface of the housing end section CEPt or CEPb.In particular, the annular groove forming the receiving channel for radial load RASC is located in the housing end enclosing section CERt or CERb and is configured to form an inner wall of the adjacent bending element for radial conformity RCBE, which has a general annular shape or configuration (as in the . Fig. 6A and Fig. 6B shown) and has an outer peripheral surface which is the mounting surface MSt or MSb.

[0055] It is to be understood that according to a type of explanation or description analogous to the above in relation to Fig. 4. Briefly shown is the ring-shaped groove that forms the receiving channel for radial loading RASC in Fig. The configuration 5 allows a very small load (e.g., radial deflections or “rolling”) of the adjacent radial conformance bending element RCBE to be at least partially absorbed or isolated, so that the load that would otherwise be transferred to stress or distort the relatively conformal enhanced axial conformance section ACP or other structures of the housing end section CEP that are radially within the radial load receiving channel RSAC is significantly reduced. This results in more stable operation of the TAG lens 170E and is synergistic with the use of enhanced axial conformance sections ACP as disclosed here.

[0056] Fig. 6A and Fig. Figure 6B are isometric and top-view diagrams of a TAG 170F lens, which is substantially similar to or the same as that shown in Figure 6B. Fig. The TAG lens 170E shown in Figure 5 includes a generic implementation of an external reservoir configuration 280, which can be understood based on the disclosure contained in the aforementioned 319 application. Therefore, the Fig. 6A and Fig. Figure 6B, without further description, can be understood as illustrative diagrams containing different views of various similarly numbered elements and features described here with reference to previous figures.

[0057] Although the improved axial conformity (ACP) sections briefly described above achieved improved axial conformity through reduced-thickness configurations that modified and reduced their geometric section properties to decrease axial stiffness, it is understood that a similar result can be achieved by reducing the elastic modulus of an ACP section without necessarily reducing its thickness along the axial direction. For example, it is known that a part such as, e.g.,A housing end section (CEP) can be manufactured from 3D-printed and sintered metal powders to provide a desired porosity level in a desired area, as disclosed, for example, in US patent applications US 2006 / 0 211 802 A1 and / or US 2010 / 0 137 990 A1 or similar, all of which are incorporated herein by reference. It is known that the elastic modulus of a metal material can be very roughly proportional to its density if the density is achieved by a manufacturing technique that provides a practical and desired percentage of porosity, according to known methods.Thus, when using such manufacturing techniques in an implementation according to the principles disclosed herein, in each housing end section at least its corresponding improved axial conformity section comprises a material region of a metal composition containing a porosity that reduces its mean density to at most 75% of its non-porous density, extending around its associated window installation section over an angle of intersection of at least 270 degrees about the optical axis. For descriptive purposes, it is to be understood that such an improved axial conformity section may have a shape or projection along the axial direction that approximates the shape of the various recessed surfaces disclosed herein, but it need not contain a recessed surface because its conformity is improved by its reduced material modulus rather than its cross-section.It is understood that its porosity or density may be relatively uniform in some implementations, or it may be graduated along the axial or radial direction in others. The use of a reduced-density porous material need not be limited to the Improved Axial Conformance (ACP) sections—it can be used in part or all of the Housing End Section (CEP), if desired.

[0058] Although preferred implementations of the present disclosure have been presented and described, numerous variations of the presented and described arrangements of features and workflows will be apparent to a person skilled in the art based on this disclosure. Various alternative forms may be used to implement the principles disclosed herein. In addition, the various implementations described above may be combined to create further implementations. All US patents and US patent applications referenced in this specification are fully incorporated herein by reference. Aspects of the implementations may be modified, if necessary, to incorporate concepts from the various patents and applications to create yet more implementations.

[0059] These and other modifications may be made to the implementations in light of the detailed description above. In general, the terms used in the following claims should not be interpreted as limiting the claims to the specific implementations disclosed in the specification. Rather, they should be interpreted as encompassing all possible implementations based on the principles and doctrines disclosed herein, together with the full range of equivalents to which such claims are entitled.

Claims

[1] Tunable sound gradient lens (TAG lens) (170A - F) comprising the following: a controllable sound wave generating element (220); a light-refracting fluid (250); a lens housing (210) surrounding a housing cavity (CC), wherein: a working volume (OPV) of the refractive fluid (250) is contained in the housing cavity (CC) and the controllable sound wave generating element (220) is arranged within the lens housing around an optical path (OPATH) passing through the working volume (OPV), wherein an axial direction of the TAG lens (170A - F) is defined as parallel to an optical axis (OA) of the optical path (OPATH); and the working volume (OPV) of the light-refracting fluid (250) to change its refractive index along the optical path (OPATH) in response to the application of a sound wave by the sound wave generating element (220) in accordance with how the TAG lens (170A - F) is controlled, is capable of providing a periodically modulated optical power variation for the TAG lens (170A - F) when a periodic drive signal is applied to the sound wave generating element (220); and the lens housing (210) comprises the following: a casing wall section (CWP) that generally extends along the axial direction, and first and second housing end sections (CEPt, CEPb) extending generally transversely to the axial direction, each housing end section (CEPt, CEPb) comprising a centrally located window configuration (WCFt, WCFb) comprising a window (214t, 214b) mounted along the optical path (OPATH) in a window mounting section (WMPt, WMPb) and a housing end termination section (CERt, CERb) that is at least partially aligned with and sealed to the housing wall section (CWP), where: Each window mounting section (WMPt, WMPb) has a total axial window mounting dimension (OWMDt, OWMDb) defined between two parallel window mounting boundary planes perpendicular to the optical axis (OPATH), which coincide with the most distant inner and outer surfaces of that window mounting section (WMPt, WMPb), respectively; and Each housing end section (CEPt, CEPb) further comprises a respective improved axial conformity section (ACPt, ACPb) which is coupled and thus sealed between its associated window mounting section (WMPt, WMPb) and housing end liner section (CERt, CERb) and holds its associated window mounting section (WMPt, WMPb) in place and is configured to improve an axial deflection amplitude of its associated window mounting section (WMPt, WMPb) relative to its associated housing end liner section (CERt, CERb) when the periodic drive signal is applied to the sound wave generating element (220), wherein: in each housing end section (CEPt, CEPb) its corresponding improved axial conformity section (ACPt, ACPb) comprises a first reduced thickness region (RTR1t, RTR1b) characterized by a reduced material thickness (RMT1t, RMT1b) along the axial direction which is at most 75% of the total axial window mounting dimension (OWMDt, OWMDb) of its associated window mounting section (WMPt, WMPb) and which extends around its associated window mounting section (WMPt, WMPb) over an angle of intersection of at least 270 degrees around the optical axis (OA). [2] TAG lens (170A - F) according to claim 1, wherein in each housing end section (CEPt, CEPb) the first area of ​​reduced thickness (RTR1t, RTR1b) is characterized by a reduced material thickness (RMT1t, RMT1b) along the axial direction, which is at most 65% of the total axial window mounting dimension (OWMDt, OWMDb) of its associated window mounting section (WMPt, WMPb). [3] TAG lens (170A - F) according to claim 1, wherein in each housing end section (CEPt, CEPb) the first area of ​​reduced thickness (RTR1t, RTR1b) is characterized by a reduced material thickness (RMT1t, RMT1b) along the axial direction, which is at most 55% of the total axial window mounting dimension (OWMDt, OWMDb) of its associated window mounting section (WMPt, WMPb). [4] TAG lens (170A - F) according to claim 1, wherein in each housing end section (CEPt, CEPb) the first reduced thickness region (RTR1t, RTR1b) comprises a first recessed surface (RS1t, RS1b) which is equal in area to or greater than the first reduced thickness region (RTR1t, RTR1b) and which is recessed along the axial direction relative to an adjacent surface of its associated housing end section (CEPt, CEPb) and which limits the reduced material thickness of the first reduced thickness region along the axial direction. [5] TAG lens (170A - F) according to claim 4, wherein at least one of the housing end sections (CEPt, CEPb) comprises a window mounting section (WMPt, WMPb), a housing end framing section (CERt, CERb) and an improved axial conformity section (ACPt, ACPb), all formed in a single continuous piece of material, wherein the first recessed surface (RS1t, RS1b) comprises a surface section of a groove formed in the single continuous piece of material. [6] TAG lens (170A - F) according to claim 5, wherein the TAG lens (170A - F) has a general cylindrical shape and the groove formed in the single continuous piece of material is an annular groove. [7] TAG lens (170A - F) according to claim 4, wherein the first recessed surface (RS1t, RS1b) of at least one housing end section (CEPt, CEPb) is located in an inner surface (217t, 217b) of this housing end section (CEPt, CEPb). [8] TAG lens (170A - F) according to claim 7, wherein the improved axial conformity section (ACPt, ACPb) of at least one housing end section (CEPt, CEPb) comprising the first recessed surface (RS1t, RS1b) located in its inner surface (217t, 217b), further comprising a second recessed surface (RS2t, RS2b) located in an outer surface (216t, 216b) of this housing end section (CEPt, CEPb), wherein the second recessed surface (RS2t, RS2b) is recessed along the axial direction relative to an adjacent surface of its associated housing end section (CEPt, CEPb) and extends around its associated window mounting section (WMPt, WMPb) over a cutting angle of at least 270 degrees around the optical axis (OA). [9] TAG lens (170A - F) according to claim 8, wherein the second recessed surface (RS2t, RS2b) is one of the following: configured to be aligned along the axial direction at least on a portion of the first recessed surface (RS1t, RS1b), and the second recessed surface (RS2t, RS2b) limits the reduced material thickness (RMT1t, RMT1b) of at least a portion of the first reduced thickness area (RTR1t, RTR1b) along the axial direction; or configured not to be aligned with any part of the first recessed surface (RS1t, RS1b) along the axial direction, and a separation distance (SEP) along the axial direction between first and second planes, which respectively coincide with the most distant recessed sections of the first (RS1t, RS1b) and second recessed surfaces (RS2t, RS2b), is at most 55% of the total axial window mounting dimension (OWMDt, OWMDb) of its associated window mounting section (WMPt, WMPb). [10] TAG lens (170A - F) according to claim 8, wherein the first (RS1t, RS1b) and the second recessed surface (RS2t, RS2b) comprise annular recessed surfaces, each extending over a 360-degree angle of intersection around the optical axis (OA). [11] TAG lens (170A - F) according to claim 1, wherein in each housing end section (CEPt, CEPb) its associated housing end framing section (CERt, CERb) comprises sections defining a bearing surface plane (ASP) that is nominally perpendicular to the optical axis (OA), and all outer surfaces of its associated window mounting section (WMPt, WMPb) are recessed along the axial direction relative to the bearing surface plane (ASP) by a distance along the axial direction that is greater than the improved axial deflection amplitude of this associated window mounting section (WMPt, WMPb). [12] TAG lens (170A - F) according to claim 1, wherein; in at least one housing end section (CEPt, CEPb) its associated housing end framing section (CERt, CERb) contains a mounting surface (MSt, MSb) around its periphery configured to receive a mounting element that exerts a force on the mounting surface (MSt, MSb) along a radial direction perpendicular to the optical axis (OA); and This at least one housing end section (CEPt, CEPb) further comprises a radial isolation configuration for radial loading (RSIC) comprising at least one radial loading receiving channel (RSAC) or radial conformity bending element (RCBE) extending over a section angle of at least 270 degrees around the optical axis (OA) and located between its mounting surface (MS) and the first reduced thickness region (RTR1t, RTR1b) of its associated enhanced axial conformity section (ACPt, ACPb) along the radial direction. [13] TAG lens (170A - F) according to claim 12, wherein: the TAG lens (170A - F) has a generally cylindrical shape; the first region of reduced thickness (RTR1t, RTR1b) is an annular region; and The radial loading channel (RASC) comprises an annular groove formed in an outer surface of this at least one housing end section. [14] TAG lens (170A - F) according to claim 13, wherein the annular groove forming the receiving channel for radial loading (RASC) is one of the following: is located between the housing end framing section (CERt, CERb) and the first reduced thickness area (RTR1t, RTR1b); or is located in the housing end enclosing section (CERt, CERb) and is configured to form an inner wall of an adjacent bending element for radial conformity (RCBE) which has a ring shape and an outer peripheral surface which is the mounting surface (MSt, MSb). [15] TAG lens (170A - F) according to claim 1, wherein at least the improved axial conformity section (ACPt, ACPb) and the window configuration (WCFt, WCFb) of each housing end section (CEPt, CEPb) are configured such that a resonance mode of the TAG lens (170A - F) comprises the axial displacement of the window mounting section (WMPt, WMPb) relative to its associated housing end framing section (CERt, CERb), wherein the resonance bandwidth of this resonance mode, as specified by the amplitude of the axial displacement of the window mounting section (WMPt, WMPb) relative to its associated housing end framing section (CERt, CERb), includes the frequency of the periodic drive signal applied to the sound wave generating element (220). [16] Tunable sound gradient lens (TAG lens) (170A - F) comprising the following: a controllable sound wave generating element (220); a light-refracting fluid (250); a lens housing (210) surrounding a housing cavity (CC), wherein: a working volume (OPV) of the refractive fluid (250) is contained in the housing cavity (CC) and the controllable sound wave generating element (220) is arranged within the lens housing (210) around an optical path (OPATH) passing through the working volume (OPV), wherein an axial direction of the TAG lens (170A - F) is defined as parallel to an optical axis (OA) of the optical path (OPATH); and the working volume (OPV) of the refractive fluid (250) to change its refractive index along the optical path (OPATH) in response to the application of a sound wave by the sound wave generating element (220) in accordance with how the TAG lens is controlled, is capable of providing a periodically modulated optical power variation for the TAG lens (170A - F) when a periodic drive signal is applied to the sound wave generating element (220); and the lens housing (210) comprises the following: a casing wall section (CWP) that generally extends along the axial direction, and first and second housing end sections (CEPt, CEPb) extending generally transversely to the axial direction, each housing end section (CEPt, CEPb) comprising a centrally located window configuration (WCFt, WCFb) comprising a window (214t, 214b) mounted along the optical path (OPATH) in a window mounting section (WMPt, WMPb) and a housing end termination section (CERt, CERb) that is at least partially aligned with and sealed to the housing wall section (CWP), where: Each housing end section (CEPt, CEPb) further comprises a respective improved axial conformity section (ACPt, ACPb) which is coupled and thus sealed between its associated window installation section (WMPt, WMPb) and housing end liner section (CERt, CERb) and holds its associated window installation section (WMPt, WMPb) in place and is configured to improve an axial deflection amplitude of its associated window installation section (WMPt, WMPb) relative to its associated housing end liner section (CERt, CERb) when the periodic drive signal is applied to the sound wave generating element (220), wherein: in each housing end section (CEPt, CEPb) at least its corresponding improved axial conformity section (ACPt, ACPb) comprises a material area of ​​a metal composition containing a porosity that reduces its mean density to at most 75% of its non-porous density, and which extends around its associated window mounting section (WMPt, WMPb) over a section angle of at least 270 degrees around the optical axis (OA).

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