Patent Application
20240081633
The present disclosure relates generally to miniaturized optical imaging and illuminating systems, apparatus, and devices. More specifically, this disclosure presents methods, systems, apparatuses, and devices to realize miniaturized medical imaging based on the optical endoscopic catheter including the Optical Coherence Tomography, Raman Spectroscopy, and/or Fluorescence Spectroscopy techniques.
Accurate diagnosis and treatment of diseases in luminal organs such as the coronary arteries, the pulmonary airways, and the gastrointestinal tract are difficult due to the inaccessibility of lesions, particularly in in-vivo cases. This is the main drive behind the miniaturization of optical imaging and illuminating (for therapeutic purposes) systems. One of the commonly used imaging systems is the endoscopic optical coherence tomography (OCT) catheter. In a typical endoscopic catheter, optical power is delivered via an optical fiber to the distal end of the catheter and then it is re-directed and focused into the tissue via several cascaded optical components. Two common approaches of re-directing and focusing the light are based on (i) graded-index (GRIN) lenses and prisms and (ii) angle polished ball lenses. In the former, the GRIN lens focuses the light and then the prism re-directs the light toward the tissue (in the radial direction, relative to the length of fiber) where one needs to perform imaging and/or light illumination. The latter can be seen as a prism and a lens integrated into one device, where the angle polished facet section re-directs (often by 90 degrees) the light coming from the fiber toward the lens, and the lens focuses the light into a tissue. In the case of imaging, scattered light from the tissue is collected by the same lens and re-directed toward the fiber via angle polished facet. Then the fiber delivers this light to a post-processing system (often to an interferometric arm and detectors) for processing and forming images. The endoscopic catheter (including fiber and other optical components attached to it) is moved back and forth and rotated along its axis (e.g., about a longitudinal axis which runs the length of the fiber) to reconstruct a 3D image of the scene (e.g., tissue).
This summary is provided to introduce a selection of embodiments in a simplified form. Embodiments will be described in further detail below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is this summary intended to be used to limit the claimed subject matter's scope.
According to some embodiments, an apparatus for dynamically controlling propagation directions and shape of light (e.g., focusing, expanding/condensing the beam width, coupling in and out of substrate), sorting light based on its properties (e.g., polarization, angle, and/or wavelength) is disclosed.
In an aspect, an optical system is disclosed. The optical system includes a substrate having a first surface and a second surface, and a first reflector disposed on the substrate and configured to receive light. The light includes at least one of a first wavelength of light and a second wavelength of light. The first reflector is configured to reflect the first wavelength of light along a first light path toward a first diffractive lens and to transmit the second wavelength of light toward a second reflector. The second reflector is configured to reflect the second wavelength of light along a second light path toward a second diffractive lens.
In another aspect, an optical system is disclosed having a substrate with a first surface and a second surface, and a collimator configured to receive and collimate input light. The input light includes at least one of a first wavelength of light and a second wavelength of light. A first reflector is configured to reflect the first wavelength of light toward a first diffractive lens and to transmit the second wavelength of light toward a second reflector. The second reflector is configured to reflect the second wavelength of light toward a second diffractive lens.
The majority of embodiments include a light source, optical fiber, diffractive optical components (e.g., diffractive lens, diffractive gratings, metasurface-based lenses, metasurface-based grating), refractive optical elements (e.g., mirror, wavelength selective mirror, partial mirror, substrate) and/or liquid crystals (LC), thin films, and polarization films (e.g., polarization reflector, absorptive polarizer, half waveplate, quarter waveplate) to control, shape, sort, and guide light toward a desired direction and ultimately focus it into an object for imaging and/or illumination. Further, embodiments may include at least one optical source, at least one sensor, and at least one control module. The control module may control, tune, and adjust the functionality of each component depending on feedback from the sensor or from a user. The functionality of some components can be dynamically changed by applying an electric voltage and/or current or by changing the properties of impinging light (e.g., polarization, wavelength, angle). Further, the polarization state of light may be linear, circular, elliptical, random, unpolarized, or any arbitrary combination of them.
The methods disclosed here may include a step of receiving, using a communication device or sensor, feedback data from at least one sensor, or image processing software. Using this feedback, the control module may adjust the functionality of one or more components, and/or change the wavelength, polarization, or other properties of the input light to improve or adjust the performance of the system/device for imaging and/or illuminating purposes.
Both the foregoing summary and the following Detailed Description provide examples and are explanatory only. Accordingly, the foregoing summary and the following Detailed Description should not be considered to be restrictive. In addition to those set forth herein, further features or variations may be provided. For example, embodiments may be directed to various feature combinations and sub-combinations described in the Detailed Description.
The accompanying drawings presented in this disclosure partially constitute the disclosure and illustrate different embodiments. The incorporated drawings may contain representations of various copyrights and trademarks owned by the Applicant. All rights to various trademarks and copyrights represented herein are vested in and the property of the Applicant. The Applicant retains and reserves all rights in their trademarks and copyrights included herein, and grants permission to reproduce the material only in connection with reproduction of the granted patent and for no other purposes.
Furthermore, the drawings may contain captions and/or text that may explain certain embodiments of the present disclosure. These text and captions are included for non-limiting, explanatory, and illustrative purposes of certain embodiments described in the present disclosure.
Embodiments of the present invention are described more fully hereinafter with reference to the accompanying drawings; however, alternative configurations and embodiments are also possible without departing from the scope of the present application. Thus, the present application should not be construed as limited to the embodiments set forth herein. Rather, the illustrated and described embodiments are provided as examples to convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity.
It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another region, layer, or a section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present disclosure.
As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “compromising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”.
Throughout this disclosure, the term “arbitrary” may be used herein to describe of being any material, shape, size, features, order, type or kind, orientation, position, quantity, components, and arrangements of components with single and/or combinations of components that may allow the present disclosure or that specific component to fulfill the objectives, function, and intents of the present invention or that specific component/system within the invention.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
By way of introduction, conventional optical illuminating and imaging systems as described previously have various drawbacks. For example, systems that rely on GRIN and ball lenses suffer from significant optical aberration including spherical aberration and astigmatism, which degrade the imaging resolution. Although one can mitigate these aberrations by cascading several lenses similar to microscope objective lenses, the large size and high cost of systems with multiple lenses render this approach expensive and impractical.
Besides the low imaging resolution, refractive-based lenses (e.g., spherical lenses) have limited functionality. They cannot perform polarization-resolved imaging or multispectral imaging, and their focal lengths are fixed (i.e., cannot be adjusted or changed). Furthermore, these lenses should be cascaded with other bulky optical components such as prisms to perform imaging in the radial direction (e.g., orthogonal to fiber length in fiber-based endoscope), which hinders further miniaturization of the imaging system. Because most of the fiber-based endoscope designs are based on the finite/finite conjugate design (point to point focusing and imaging, fiber core to focal spot, and vice versa) the optical path error (e.g., due to fabrication tolerances) between the fiber and lens not only can cause aberration and reduce the resolving power but also can change the effective focal length of the imaging system. Due to its solid nature, using a prism makes it very difficult to place any other component between the fiber and the lens, thereby limiting the functionality of the whole system. For example, it may be very hard to control or sort the light, which is transmitted between fiber and lens via a prism, based on its polarization and/or wavelength. Also, both refractive lenses and prisms are passive optical components without adjustability, which prevents the optical system from being tuned or dynamically operated. In this disclosure, several systems and methods are described that address these problems and shortcomings.
The present disclosure describes devices, apparatuses, and systems to facilitate light control for imaging and illuminating purposes in a compact and small form-factor. Further, the present disclosure describes various methods to enable multi-zoom imaging, multi-spectral imaging, and polarization-resolved imaging. Further, the present disclosure relates generally to multi-functional small form-factor optical systems to focus light into tissue/organs for imaging and illumination via an optical fiber and stack of miniaturized optical components and devices. Optical components and devices can be based on diffractive optics, metasurfaces, and refractive optics and/or combinations thereof.
In the present disclosure, diffractive components (e.g., gratings, lenses) include arbitrary arrays of subwavelength scatterer, resonator, and/or nanostructures. These scatterers, resonators, and/or nanostructures may be referred to herein as building blocks. Building blocks can individually or collectively control one or more basic properties of light such as phase, amplitude, polarization, spatial and temporal profile, the direction of propagation, angle of rays, or combinations of these properties at the same time. For example, diffractive lenses are very thin lenses that can focus, diverge or converge the impinging light. Incoming light can have arbitrary profile and/or angular distribution. In general, diffractive gratings diffract impinging light to one or several different orders (e.g., ±1, ±2, ±3, etc.) depending on the design parameters (e.g., pitch and/or pattern) of the gratings. Diffractive axicons can generate Bessel beams of different orders (e.g., Jo, Ji, etc.). Bessel beams have unique non-diffractive properties where light can stay focused for an extended distance compared to other counterparts such as diffractive lenses. Diffractive components' building blocks may be made of materials including semiconductors (e.g., amorphous silicon, polycrystalline silicon, silicon carbide, gallium nitride, gallium phosphide), crystals (e.g., silicon, lithium niobate, diamond), dielectrics (e.g., silicon dioxide, silicon nitride, aluminum oxide, hafnium oxide, titanium dioxide, indium oxide), polymers (e.g., photoresist, PMMA), metals (e.g., silver, aluminum, gold), two-dimensional (2D) materials (e.g., graphene, boron nitride), phase change materials (e.g., chalcogenide, vanadium dioxide) or any mixtures or alloys thereof.
In the present disclosure, metasurfaces are advanced forms of diffractive components and may be referred to as meta-gratings (gratings based on metasurface designs), meta-lenses (lenses based on metasurface designs), and meta-hologram (holograms based on metasurface designs). These metasurfaces are multifunctional flat components with engineered dispersive, polarization, and angular responses and may be fabricated using various approaches such as optical lithography, deep-ultraviolet lithography, electron beam lithography, nanoimprinting, reactive ion etching, electron beam deposition, sputtering, plasma-enhanced deposition, atomic layer deposition, and any combination of the aforementioned processes with any arbitrary orders. Metasurface building blocks may be made of similar materials mentioned above for diffractive components.
Throughout the present disclosure, “optical fiber,” which may also be referred to herein as just “fiber,” may refer to a flexible, transparent fiber made by drawing glass (silica) or plastic, or other materials. Optical fibers referred to herein may include single-mode fiber, multimode fiber, photonic crystal fiber, and any other special-purpose fiber. Fiber may be connected to a bare ferrule, or connector comprising ferrule. Ferrule type may be a ferrule connector (“FC”), Lucent connector, angle polished connector (“APC”), physical contact (“PC”) connector, Ultra-Physical Contact (UPC), or any combination of them. Other connectors may be used without departing from the scope of the present disclosure. The ferrule can be made of glass, ceramic, plastic, or any other materials. Fiber connectors can be FC, PC, APC, subscriber connector (“SC”), or any combination thereof. The ferrule may be customized with arbitrary shapes and sizes. The operating wavelength of fiber can be Ultra-Violet (UV), visible, Near Infrared (NIR), Short-Wave Infrared (SWIR), or/and longer or shorter wavelengths. Fibers can have a protective layer, or may be enclosed with other plastic tubes, polymer tubes, glass tubes, and/or torque coils. Different types of tubes (e.g., plastic, polymer, glass) generally are used as a protective enclosure for optical systems and devices. A torque coil is used to transfer torque to the optical system (e.g., the imaging/illuminating probe) for rotation and thus performs radial imaging/illuminating.
In the present disclosure, the term “optical source” refers to a coherent, partially coherent, or incoherent light source that may be based on any technology such as, but not restricted to, swept-source laser, light-emitting diodes (LEDs), edge-emitting semiconductor laser diodes, vertical-cavity surface-emitting lasers (VCSELs), supercontinuum sources, superluminescent diodes, white light sources, and halogen lamps. The wavelength of the light source may be in deep-UV, UV, visible, NIR, SWIR, mid-infrared, or far-infrared ranges depending on the application of the catheter (for example, for imaging, or therapeutic applications wavelength may be different). The light may be delivered as pulses of energy (e.g., pulse laser) or as a Continuous Wave (CW).
Throughout the present disclosure, the term “color filter” refers to a device that selectively transmits or reflects light of different colors (i.e., wavelengths). Color filters can be based on various mechanisms such as absorption (e.g., using a dye, pigment, plasmonic particles, metallic nanostructures), interference (e.g., thin-film, subwavelength grating, Mie resonance structure, plasmonic and metallic nanostructure), or diffraction (e.g., reflective or transmission grating). In this disclosure, a mirror may refer to a device that reflects incident light. The reflectivity of the mirror can be smaller or larger than 10%, smaller or larger than 25% smaller or larger than 75%, or smaller than 100%. The reflectivity of the mirror may be a function of light wavelength, polarization, and/or its angle of incidence.
Throughout the present disclosure, the imaging sensor may refer to any arbitrary imaging and sensing technologies to detect or capture light intensity or other light properties such as phase, angle, polarization, and wavelength. Some examples of such arbitrary imaging and sensing technologies include complementary-symmetry metal-oxide-semiconductor (CMOS), charge-coupled device (CCD), intensified charge-coupled device (ICCD), scientific CMOS (sCMOS), avalanche diode (AD), time-of-flight (ToF), Schottky diodes or any other light or electromagnetic sensing mechanism operating at deep-UV, visible, SWIR, NIR, far-infrared and/or other wavelengths.
Further, the present disclosure describes a hybrid approach based on refractive optics, diffractive optics, metasurface, and other flat optical technology (e.g., polarizers, waveplates, quarter waveplates, half-wave plates, mirrors, reflectors, partial reflectors, and color filters). The dynamic capability of various optical systems described herein may be enabled by including components configured to achieve electro-optic (e.g., by injecting carrier) or thermo-optic (e.g., by local heating) effects. Other mechanisms and devices such as LC may also be used to provide adjustability within optical systems. The dynamic capability may significantly enhance the performance and flexibility of optical systems. The multifunctional nature of cascaded planar components enables such dynamic systems to satisfy small form-factors necessary for in-vivo medical applications. The main focus of the present disclosure is on enabling small form-factor, reconfigurable, high-performance optical systems for medical imaging, diagnostic, and therapeutic purposes.
Throughout the present disclosure, dynamic components or design or in general the adjective “dynamic” as used herein may refer to components or designs having function, performance, and properties that can be adjusted over time by selectively changing the properties of light (e.g., polarization, wavelength, intensity) in response to one or more of an external optical, thermal, electrical, or mechanical signal.
Simulations in this disclosure are performed using ray-tracing methods considering the law of reflection, refraction, and diffraction. For all simulations described and illustrated herein, each ray is assumed to have a single wavelength with a very small bandwidth for sake of simplicity. It is important to note that in experiments and in a real device, rays (e.g., input light) may have considerable bandwidth which may be smaller or larger than 10 nm, smaller larger than 25 nm, smaller or larger than 50 nm, smaller or larger than 100 nm. In some embodiments, the bandwidth is between approximately 50 nm and approximately 100 nm.
In the endoscopic catheter 100, the OIIS 101 comprises two wavelength-selective reflectors (“WSR”) 104a and 104b, two diffractive gratings 106a and 106b, and two diffractive lenses 107a and 107b disposed on or in or otherwise supported by a substrate 105. Substrate 105 may be made of materials including glass (e.g., fused silica, Pyrex, high index glass, quartz), semiconductors (e.g., amorphous silicon, polycrystalline silicon, silicon carbide, gallium nitride, gallium phosphide), crystals (e.g., sapphire silicon, lithium niobate, diamond), dielectrics (e.g., silicon dioxide, silicon nitride, aluminum oxide, hafnium oxide, titanium dioxide, indium oxide), polymers (e.g., photoresist, PMMA). Here, for exemplary purposes, a glass substrate is considered. One or more of diffractive lenses 107a, 107b may be replaced with Fresnel lenses, metasurface-based lenses, and/or refractive lenses (e.g., spherical lenses, aspherical lenses, free-form lenses). The WSRs 104a and 104b may be disposed on a first surface 105a. The WSRs may be positioned at an angle (e.g., approximately 37 degrees, 45 degrees, or 50 degrees) relative to the first surface 105a. The reflection value of WSR for the desired wavelength may be smaller or larger than 95%, smaller or larger than 90%, and smaller or larger than 80%, smaller or larger than 70% while allowing other wavelengths to pass through with a maximum transmission value smaller or larger than 95%, smaller or larger than 90%, smaller or larger than 80%, smaller or larger than 70%. In some embodiments, the reflection value of WSR for the desired wavelength may be between approximately 80% and approximately 95%. In some embodiments, the transmission value of WSR for the desired wavelength may be between approximately 80% and approximately 95%. The first diffractive lens 107a may also be disposed on the first surface 105a in between the two WSRs 104a and 104b. The two diffractive gratings 106a and 106b as well as the second diffractive lens 107b may be disposed on a second surface 105b opposite the first surface 105a of the substrate. The first and second surfaces 105a and 105b may be substantially parallel or may have an angle relative to each other. This angle can be smaller or larger than 5 degrees, smaller or larger than 10 degrees. The first and second surfaces 105a and 105b may be planar and substantially parallel to each other. The positions, sizes, and shapes of each component on the substrate 105 may be selected to receive and direct light in a specific way, as will be discussed herein below with respect to
For applications where the endoscopic catheter 100 is used for optical coherence tomography, the operating wavelength (i.e., the wavelength of light received by the OIIS) may be in the NIR or SWIR regions (e.g., wavelengths between 800 nm to 1700 nm). Such wavelengths advantageously allow for the penetration of light into the tissue for depth imaging and illumination. For systems using wavelengths in the range of approximately 800 nm to approximately 1700 nm, diffractive lenses can include an array of silicon nanostructures on a glass substrate. Silicon has a high refractive index (e.g., refractive index n>3) and negligible material loss in this wavelength range. Thus, silicon nanostructures on a glass substrate may enable the low-loss and strong light-nanostructures interaction necessary to make high-efficiency and high-performance flat devices and components.
In the ray-tracing simulation shown in
Rays 108a reflected by WSR 104a enter substrate 105 substantially perpendicular to the first surface 105a. The rays 108a travel through the substrate 105 toward the second surface 105b on which is disposed the diffractive grating 106a. The diffractive grating 106a is sized and positioned to intercept the rays 108a, accounting for a small amount of light divergence that may occur. The diffractive grating 106a diffracts the rays 108a into angles larger than the Total Internal Reflection (TIR) angle of the substrate. Diffracted light bounces off of the first surface 105a due to TIR and travels toward second diffractive grating 106b disposed on the second surface 105b. The second diffractive grating 106b is designed to diffract light such that, after the diffraction event, the light travels through the substrate 105 at an angle substantially perpendicular to the first and second surfaces 105a and 105b. A diffractive lens 107a is positioned on the first surface 105a such that it receives light diffracted from the second diffractive grating 106b. Diffractive lens 107a may be sized to account for an increase in divergence of the light rays 108a as they traveled through the optical system. The diffractive lens 107a focuses rays 108a into a diffraction-limited spot at a focal length (e.g., f1=0.9 mm) relative to the first surface 105a of the substrate 105. Here, the focal length of 0.9 mm is selected for exemplary purposes and the focal length may be smaller or larger than 1 mm, smaller or larger than 5 mm, smaller or larger than 10 mm without departing from the scope of the present disclosure.
Referring to
Notably, diffractive lenses may have chromatic aberration whereby changing the wavelength of input light causes the focal spot size to become larger than the diffraction limit, and focusing efficiency degrades. However, in the catheter 100, each of the diffractive lenses 107a and 107b can be designed for a particular operating wavelength (e.g., 1300 nm and 800 nm, respectively). This enables each diffractive lens to achieve optimal performance in terms of imaging resolution and focusing efficiency. One other important point about endoscopic catheter 100 is that the light exiting the fiber facet 102 is diverging. By controlling the optical path length that light travels before reaching the diffractive lens, the beam waist may also be controlled. The longer the light travels, the larger the beam waist becomes. Therefore, for a fixed focal length (or working distance of the lenses) the numerical aperture (“NA”) of the OIIS may also be controlled, assuming the beam waist is equal to the diameter of the lens used to focus the light. Another advantage of having two focal spots (on top and bottom of OIIS) is to increase the imaging speed and/or frame rate. Generally, OIIS rotates along the fiber axis (X-direction) to perform 3D imaging. Having focal spots on top and bottom, one may perform full radial imaging by rotating the OIIS 180 degree (rather than 360 degrees). In other words, top lens 107a forms an image of the top half-circle, and bottom lens 107b forms the bottom half-circle. By stitching these two images using, for example, image post-processing software, one may reconstruct the full image by only rotating OIIS 101 through 180 degrees which can enhance the speed of imaging. In another scenario where OIIS 101 rotates 360 (degrees), the frame rate may be doubled by combing images captured by the top and bottom lenses 107a and 107b.
In addition to using the OIIS 101 to image a surrounding environment as discussed above, the same OIIS 101 may be utilized for illumination of the surrounding environment (e.g., therapeutic purposes). A therapeutic protocol may require the use of multiple different wavelengths of light, for example, light having wavelengths in the UV or visible wavelength range. Depending on the particular wavelengths to be used, other materials, such as titanium dioxide or hafnium dioxide (with negligible absorption loss in these wavelength ranges and relatively high refractive index of n=˜2.5), may be used to form one or more of the components, such as the diffractive gratings or diffractive lenses. The titanium dioxide or hafnium dioxide components may be better suited to assembly on a different type of substrate depending on operating wavelength.
The number of spectral channels and achievable focal lengths can be increased by stacking more WSRs and other components along the X-direction as shown in
An achromatic lens 210, which may be based on metasurface design or an achromatic refractive lens, may be used to collimate rays 208a-d of all different wavelengths. After being collimated by the achromatic lens 210, the rays 208a-d encounter a series of wavelength selective reflectors that are positioned at an angle (e.g., approximately 45 degrees) relative to a first surface 205a of a substrate 205. Each of the WSRs may be configured to reflect or transmit light associated with different wavelengths. The rays 208a-d encounter a first WSR 204a after being collimated by achromatic lens 210. The WSR 204a is designed to reflect rays 208a through substrate 205 towards the first diffractive lens 207a, which may be disposed on a second surface 205b opposite a first surface 205a. The first diffractive lens 207a focuses the rays 208a at a first focal length. For example, the first focal length may be approximately 0.5 mm. The three other spectral channels (i.e., the second, third, and fourth rays 208b-d) pass through WSR 204a and continue unperturbed toward the second WSR 204b.
WSR 204b is designed to reflect rays 208b through the substrate 205 toward a second diffractive lens 207b which focuses the rays 208b at a second focal length (e.g., approximately 1 mm). WSR 204b allows rays 208c-d to pass through toward WSR 204c without interruption. WSR 204c is configured to reflect rays 208c centered at the third wavelengths toward a third diffractive lens 207c. The rays 208c are focused by the corresponding diffractive lens 207c at a third focal length (e.g., approximately 1.5 mm). WSR 204c allows rays 208d to pass through without interruption. Finally, the rays 208d corresponding with the fourth spectral channel reach mirror 209 and are re-directed toward the diffractive grating 206a. In some embodiments, a fourth WSR configured to reflect rays 208d may be used in place of a mirror.
Rays 208d are diffracted by a first diffractive grating 206a such that the diffracted rays 208a travel at angles larger than the TIR of the substrate; therefore, the rays 208d are reflected inside of the substrate when they encounter the first surface 205a of the substrate 205. The rays 208d traveling in TIR encounter a second diffractive grating 206b that again diffracts the rays 208d. Specifically, the diffractive grating 206b diffracts rays 208d toward the diffractive lens 207d to be focused at a fourth focal length (e.g., approximately 2 mm).
Utilizing gratings (e.g., diffractive gratings 206a and 206b) provides an extra degree of freedom in directing and shaping light in a small form-factor. For example, using two diffractive gratings, rays 208d may be focused from the top of the substrate (i.e., the first surface 205a), whereas other rays (i.e., rays 208a-c) are all focused below the substrate (i.e., from the second surface 205b). In the embodiment illustrated in
The diffractive grating 306a diffracts and spatially separates rays of different wavelengths as shown in
In the OIIS 301a, the input light (e.g., ray 308a) is spatially sorted according to the different spectral channels utilizing the dispersive response of grating 306a. Other parameters, such as the thickness of the substrate 305, may also be used as a design variable in separating the different spectral channels. While diffractive lenses are described with respect to OIIS 301a, refractive lenses may be used instead of the diffractive lens without changing the functionality of the OIIS 301a.
OIIS 301a can perform imaging in the three spectral channels described, and the focal length of the system can be controlled by changing the input wavelength. For example, multiplexed input light will filter through the system as described above resulting in three light beams of different wavelengths focused at different focal lengths. Alternatively, if imaging is desired at only one of the available focal lengths, input light having a wavelength associated with that particular focal length may be provided to the OIIS 301a. While three spectral channels and associated focal lengths are described, additional channels and focal lengths may be included within the OIIS without departing from the scope of the present disclosure.
Light projected by the OIIS 301a may be reflected or otherwise scattered by a surrounding environment (e.g., an organ or tissue). At least a portion of the reflected or scattered light may be captured by the OIIS 301a via the same light paths used to deliver light to the surrounding environment but moving in the opposite direction. For example, reflected light having a first spectral channel may be captured by the diffractive lens 307b, diffracted by diffractive gratings 306b and 306a, reflected by mirror 309, shaped (e.g., converged) by diffractive lens 307a, and coupled into the fiber 302 for transmission back to an imaging system (not shown). Reflected light having second and third spectral channels may follow a similar pattern where the light moves through the light path toward the fiber for image capture. Such light-capturing capabilities are shared by all embodiments disclosed herein.
Another OIIS 301b with similar functionality is illustrated in
While specific wavelengths and focal lengths are provided as examples for purpose of description, one of skill in the art will appreciate that other wavelengths and/or focal lengths may be selected without departing from the scope of the present disclosure.
Embodiments illustrated in
In the ray-tracing simulation shown in
Rays 408c take a different path toward a second fiber 402b via diffractive grating 406b, a second PSR 413b, and diffractive lens 407c. The PSR 413b is oriented in such a way (e.g., at approximately 45 degrees relative to the second surface 405b) that it reflects light rays 408c toward a fiber at an angle (e.g., to a direction approximately 0 degrees relative to the second surface 405b). In some embodiments, the PSR 413b only reflects light having a polarization P2 in order to prevent any stray P1 light from entering the P2 light pathway at the fiber. To further reduce the likelihood of any P1 polarization light incoupling to the P2 pathway, an absorptive polarizer 414b may be applied to a back surface of PSR 413b. The absorptive polarizer ensures that if there is any other polarization component than intended polarization, it will be absorbed to prevent it from continuing to propagate through the system along the incorrect pathway. A similar absorptive polarizer component 414a may be used on the PSR 413a to absorb stray P2 polarization light within the P1 polarization light pathway. The polarization direction of the absorptive polarizers is orthogonal to the corresponding PSRs that they are stacked against. In some embodiments, PSR 413b and absorptive polarizer 414b may be replaced by a single metallic or dielectric mirror without departing from the scope of the present disclosure. In some embodiments, the PSR 413a and absorptive polarizer 414a may also be replaced with a single metallic or dielectric mirror.
The OIIS 401a is capable of performing polarization-resolved imaging since OIIS 401a spatially separates two orthogonal polarizations of light coming from the imaged object and sends them to two fibers which will be eventually received by a processing module that may include a camera or optical sensors (not shown here) to form images. In some embodiments, the P1 and P2 polarizations of light may be coupled into two different fiber cores within a single fiber.
Another embodiment capable of polarization-resolved imaging is shown in
In addition to reducing the number of components on the OIIS 401b, the number of components within the endoscopic catheter 400b may be reduced by replacing the two fiber configurations used in 400a with one fiber having two cores in 400b. The system can be further simplified by grouping PSRs 413a, 413b and absorptive polarizers 414a, 414b. This embodiment is shown in
Another alternative embodiment for polarization-resolved imaging is shown
Another embodiment for polarization-resolved imaging is shown in
Rays 408b coupled out of the second fiber 402b are collimated by the diffractive lens 407b and are reflected by PSR 413b toward the diffractive grating 406b. An absorptive polarizer 414b may be included on the PSR 413b as shown. The rays 408b are diffracted by diffractive gratings 406b and 406c toward PSG 412. The PSG 412 allows rays 408b (i.e., rays having P2 polarization) to pass through undisturbed. The rays 408b combine with rays 408a and are focused by diffractive lens 407c at a focal length (e.g., a focal length of 0.4 mm). Rays 408a with orthogonal polarization (e.g., P1 polarization), relative to 408b, couple out of bottom fiber 402a and are collimated by diffractive lens 407a. The rays 408a are re-directed toward diffractive lens 407c via PSR 413a, diffractive grating 406a, and PSG 412. PSR 413a may include an absorptive polarizer 414a disposed thereon. PSG 412 is configured to diffract light having polarization P1; thus, rays 408a are diffracted by PSG 412 toward the diffractive lens 407c where they are focused at the focal length along with rays 408b. Due to the reciprocity of the system 400e when collecting light for imaging, each ray scattered by the imaged object is sorted based on polarization and is coupled to a corresponding fiber core. The light collected in both fiber cores is sent to the image processing module (not shown) to perform polarization-resolved imaging.
Turning to
A second portion of the rays 508a (e.g., a second spectral channel with wavelength centered at, for example, 1300 nm) from the bottom core 503a passes through WSR 504a and 504b undisturbed. This second portion of the rays 508a are reflected by WSR 504c toward diffractive grating 506c which in turn diffracts the rays toward PSG 512b. PSG 512b diffracts the second portion of rays 508a toward a diffractive lens 507d which focuses the light at a second focal length (e.g., a focal length of 0.5 mm). Similarly, a second portion (e.g., a second spectral channel with wavelength centered at, for example, 1300 nm) of the rays 508b from the top core 503b passes through WSR 504b undisturbed. The second portion of rays 508b impinge on WSR 504d where they are reflected toward the substrate 505 and a diffractive grating 506d disposed thereon. The diffractive grating 506d diffracts the second portion of rays 508b toward PSG 512b which in turn diffracts the light toward diffractive lens 507d. The diffractive lens 507d outcouples and focuses the light at the second focal length.
Thus, the OIIS 501a is capable of performing polarization-resolved imaging at two different focal lengths, where the focal length of the imaging is controlled by the center wavelength of the spectral channel of the input light. Additional fiber cores, diffractive lenses, WSRs, PSGs, and diffractive gratings may be added in sequence to the system to increase the number of spectral channels and associated focal lengths.
Rays 508b from the second core 503b pass through a diffractive lens 507d and a polarizer 514b. The polarizer 514b causes the rays 508b to have a second polarization (e.g., P2 polarization). The diffractive lens 507c and polarizer 514a are separated from the diffractive lens 507d and polarizer 514b by a spacer 515. A first portion of the rays 508b (e.g., P2 polarization, spectral channel centered at 1100 nm) are reflected by WSR 504b toward the PSG 512a. PSG 512a permits the P2 polarized first portion of rays 508b to pass therethrough where it impinges on diffractive lens 507a. The light is focused at the first focal length. A second portion of rays 508b (e.g., P2 polarization, spectral channel centered at 1300 nm) passes through the WSR 504b and are reflected by WSR 504d toward second PSG 512b. The PSG 512b permits the P2 polarized second portion of rays 508b to pass therethrough toward the diffractive lens 507b. Diffractive lens 507b focuses the second portion of rays 508b at the second focal length.
The number of components in the endoscopic catheter can be further reduced using the embodiment shown in
Rays 508b from the second fiber core 503b travel through a diffractive lens 507d and polarizer 514b where they are polarized with a second polarization (e.g., P2 polarization) opposite of the first polarization. The light impinges on the first WSR 504a where a first portion (e.g., spectral channel centered at 1100 nm) is reflected toward the PSG 512a which is configured to transmit light with polarization P2. Thus, the first portion of rays 508b passes through PSG 512a undisturbed toward diffractive lens 507a where it is focused at the first focal length. A second portion of rays 508b (e.g., spectral channel centered at 1300 nm) passes through the WSR 504a and is reflected by the second WSG 504b toward the second PSG 512b. PSG 512b is configured to transmit light with polarization P2, thus, the second portion of rays 508b passes through the PSG 512b undisturbed toward diffractive lens 507b. The lens 507b focuses the second portion of rays 508b at the second focal point. Light reflected from the environment (e.g., a surrounding tissue) enters the OIIS 501c via diffractive lenses 507a, 507b and travels in reverse through the light pathways described above for imaging purposes.
Referring now to
Rays exiting the second fiber 502b follows a separate but similar path. Rays 508b, including light centered at the first and second spectral channels, pass through diffractive lens 507d and polarizer 514b where they are approximately collimated and polarized with a second polarization (e.g., P2 polarization), respectively. Light at the first spectral channel is reflected by WSR 504c where it is diffracted by diffractive grating 506c on the second substrate 505d. Diffractive grating 506c diffracts the light toward diffractive grating 506e which diffracts the light out of the second substrate 505d toward PSG 512a. The first spectral channel of light rays 508b may exit the second substrate 505d traveling substantially perpendicular to and aligned with PSG 512a. Because this light is P2 polarized, it transmits through PSG 512a toward diffractive lens 507b where it is focused, along with the first spectral channel of rays 508a, at the first focal point. The second spectral channel of rays 508b passes through WSR 504c where they are reflected by WSR 504d configured to reflect light at the second spectral channel. The light is diffracted by diffractive grating 506d on the second substrate 505d toward diffractive grating 506f which diffracts light having the second polarization P2. The second spectral channel of light then exits the second substrate approximately perpendicular to and aligned with PSG 512b, which is configured to transmit light having second polarization P2 toward the diffractive lens 507c where it is focused, along with the second spectral channel of rays 508a, at the second focal length. Spacer 515 is placed between first substrate 505c and second substrate 505d to facilitate their assembly and angular alignment. In the system 500d, first substrate 505c and second substrate 505d are substantially parallel.
As discussed with prior embodiments, the system 500d is a reciprocal system and is configured to capture light scattered or reflected by the surrounding environment (e.g., tissues and organs). Reflected or scattered light enters the system OIIS 501d through diffractive lenses 507b, 507c and travels in reverse through the light paths described above. Thus, light having a first polarization P1 at the first and second spectral lengths is captured by first fiber 502a, and light having a second polarization P2 at the first and second spectral lengths is captured by second fiber 502b. In the first fiber 502a, light at the first spectral channel is focused at the first focal length and light at the second spectral channel is focused at the second focal length. Similarly, in the second fiber 502b, light at the first spectral channel is focused at the first focal length and light at the second spectral channel is focused at the second focal length.
In 3-dimensional medical imaging, depth information is very important for diagnosis and/or treatment. Generally, in an OCT system, resolution in the radial direction (e.g., depth into tissues of a luminal organ along the optical axis of the OIIS) is determined by the interferometry process; however, collection efficiency of OIIS depends at least in part on the depth of focus of the OIIS. Collection efficiency is defined as how much of the signal (i.e., light scattered by the tissue) at different depths can be collected by OIIS and sent to the image processing module to form images and perform analysis. However, there is a trade-off between lateral resolution (e.g., imaging resolution in the plane perpendicular to the optical axis) and its depth of focus. For example, if the NA of the OIIS increases, it focuses light to a smaller spot that may result in higher lateral resolution. However, increasing the NA also generally results in the reduction of depth of focus. Three embodiments configured to extend the depth of focus while maintaining high lateral resolution are described.
A catheter system 600a is shown in
A fiber 602 (for simplicity the ferrule which holds fiber 602 is not shown here) receives two spectral channels from the source (not shown) wherein the first spectral channel is centered at a first wavelength (e.g., 800 nm) and a second spectral channel is centered at a second wavelength (e.g., 1300 nm). The first and second spectral channels are included in rays 608 illustrated exiting the fiber 602 toward a diffractive lens 607. In some embodiments, one of the spectral channels (e.g., the second spectral channel) is roughly collimated by diffractive lens 607 while the other spectral channel (e.g., the first spectral channel) is shaped toward a more collimated beam but is not collimated. The difference in light shaping between the two spectral channels may occur because diffractive lens 607 is designed to collimate one spectral channel, while rays at the other spectral channel will not be perfectly collimated by the diffractive lens due to chromatic dispersion. Both spectral channels contain two orthogonal polarizations (e.g., P1 and P2 polarization). The rays 608 having the first spectral channel are reflected by WSR 604a designed to reflect the first spectral channel and transmit the second spectral channel. The reflected rays travel toward a first PSDL 616a on the substrate 605. The first PSDL 616a is configured to focus a portion of the first spectral channel having polarization P1 (as illustrated by solid lines) at first focal length (e.g., f1=1.2 mm) and is configured to focus a portion of the first spectral channel having polarization P2 (as illustrated by dotted lines) at a second focal length (e.g., f2=0.8 mm). Focusing light centered at the same spectral channel at both first and second focal lengths extends the depth of focus of OIIS 601a at the spectral channel. Light that is scattered by the imaged object may be captured more efficiently by the OIIS 601a if it is within a certain distance (depth of focus of each focal point) of either the first or second focal length. Depth of focus (DOF) can be defined as follows:
where n is the refractive index of the medium, λ is the wavelength of light, and NA is the numerical aperture. This DOF value determines the distance in the vicinity of the focal spot along the optical axis where the image stays focus. In an OIIS with two focal lengths, by appropriate design of parameters (e.g., wavelength, numerical aperture), it may be beneficial to have a DOF of each focal spot overlap such that the OIIS has an extended depth of focus which goes beyond what is conventionally possible.
The second spectral channel passes through WSR 604a undisturbed and is reflected toward a second PSDL 616b by a second WSR 604b. Rays with P1 polarization (as illustrated by dashed lines) are focused at a third focal length (e.g., f3=0.5 mm) and rays having P2 polarization (as illustrated by dash-dotted lines) are focused at a fourth focal length (e.g., f4=0.3 mm). As discussed above with respect to the first and second focal lengths, being able to use collected light within a range of the third and fourth focal lengths extends the depth of focus of OIIS 601a at the second spectral channel.
In an OCT imaging system or any other type of imaging system, excitation light (e.g., light delivered to a surrounding environment such as tissue) may have substantial bandwidth meaning that it is not a single wavelength with very narrow bandwidth. The excitation light may come from LEDs, swept-source laser, VCSELs, supercontinuum sources, superluminescent diodes, any other type of light source with adjustable center wavelength and/or tunable bandwidth. By designing diffractive lenses with tailored chromatic dispersion, the broad bandwidth of input light may be used to extend the depth of focus of an OIIS system. The focal length of each diffractive lens is assumed to be a function of wavelength as related in Equation 2:
In Equation 2, f is the focal length, C is a constant, λ is the wavelength, and m is an integer value. Referring now to
In this example, first and second rays with wavelength 900 nm and 1100 nm are reflected toward the diffractive lens 607a by the WSR 604a. The WSR 604a may be positioned at an angle (e.g., approximately 45 degrees) with respect to a top surface of the substrate 605 such that reflected rays enter the substrate approximately perpendicular to the top surface. The diffractive lens 607a is a normal diffractive lens where m=1 in Equation 2. Therefore, lens 607a focuses the first and second rays at first and second focal lengths (e.g., f1=0.611 mm and f2=0.5 mm), respectively, thereby expanding the depth of focus of OIIS 601b at the first and second spectral channels. Third and fourth rays (e.g., rays with wavelengths of 1200 nm and 1400 nm, respectively) pass through WSR 604a and are reflected by a second WSR 604b toward super-dispersive diffractive lens 617. The focal lengths of this super-dispersive diffractive lens 617 follow Equation 2 with m=3. With a super-dispersive diffractive lens, a larger focal length shift is achieved by changing the wavelength. This effect is illustrated in the ray-tracing simulation where the third ray is focused at a third focal length (e.g., 1.588 mm at wavelength 1200 nm) and the fourth ray is focused at a fourth focal length (e.g., 1 mm at wavelength 1400 nm). Thus, the super-dispersive diffractive lens may be used to further expand the depth of focus of OIIS 601b at the third and fourth spectral channels.
Referring now to
Third and fourth rays pass through second WSR 604a undisturbed. Third rays are reflected by third WSR 604c and while fourth rays pass through third WSR 604c and are reflected by fourth WSR 604d. Third rays are focused by third axicon 618c having a third NA (e.g., NA3=0.5) and a fourth axicon 618d having a fourth NA (e.g., NA4=0.8), respectively. With increasing NA, the depth of the focal spot is reduced, and resolution is increased. Overall, the depth of focus of OIIS 601c is increased by utilizing one or more axicons for focusing. One or more depths of focus may be selected for imaging by changing the spectral channel of the input signal; thus, the OIIS 601c provides adjustable depth of focus and NA.
In the catheter system 700a shown in
Initially, the system 700a is described having the LCG 719a in an OFF state. Rays 708 are diffracted by diffraction grating 706a toward the OFF LCG 719a. The OFF LCG 719a diffracts the rays 708 toward diffractive lens 707a where they are focused at a first focal length (e.g., a focal length of 0.5 mm). This is the end of the light path when LCG 719a is off.
In a second scenario wherein the LCG 719a is ON, rays 708 are diffracted by diffractive grating 706a toward the LCG 719a and do not interact with LCG 719a. Instead, the rays 708 are reflected by the top surface of the substrate 705 due to TIR. After reflecting from the top surface 705a, the rays 708 reach a second LCG 719b. When the second LCG 719b is OFF, rays 708 are diffracted toward diffractive lens 707b where they are focused at a second focal length (e.g., a focal length of 1.5 mm). This is the end of the light path when LCG 719a is on and LCG 719b is off.
In a third scenario, both LCG 719a and LCG 719b are ON; thus, the rays 708 will not interact with either of the first and second LCGs 719a, 719b. Rays 708 propagate through the substrate 705 in TIR until they reach the second diffractive grating 706b. After being diffracted by the grating 706b, rays 708 are focused by diffractive lens 707c at a third focal length (e.g., a focal length of 3 mm).
By switching LCGs ON and OFF, the OIIS 701a can be reconfigured such that light is emitted (and may also be collected via reciprocity of the system) at a desired focal length. In some embodiments, three discrete focal lengths of (e.g., 0.5 mm, 1 mm, and 3 mm) can be achieved. One of skill in the art will appreciate that the number of achievable focal lengths can be increased or decreased by cascading more or fewer LCGs, respectively, along with other appropriate components (e.g., diffractive gratings and/or diffractive lenses designed to have selected focal lengths).
Initially, the light path will be described with respect to a first scenario (illustrated with solid lines) wherein the first LCHWP 720a is in the OFF state. When in the OFF state, the LCHWP 720a acts as a Half Waveplate (HWP) and changes the incoming linearly polarized rays into their orthogonal state (e.g., P2 polarization). The rays interact with a first Polarization-Selective Reflector (“PSR”) 713a. All PSRs in the system (e.g., 713a, 713b, 713c, 713d) are co-polarized with the absorptive polarizer 714, meaning that if the linearly polarized rays 708 pass through 714, the rays 708 will also pass through the PSRs. In this example, the absorptive polarizer 714 transmits rays with P1 polarization; PSRs transmit P1 polarized rays and reflect P2 polarized rays. Because rays 708 passing through the first LCHWP 720a in the OFF state switch polarization (e.g., switch from P1 to P2 polarization), the rays will be reflected by PSR 713a toward a diffractive lens 707a disposed on the substrate 705. The lens 707a focuses the rays 708 at a first focal length (e.g., a focal length of 0.25 mm).
In a second scenario, the first LCHWP 720a is in ON state and the second LCHWP 720b is in OFF state. In this case, after passing through 720a rays 708 do not change polarization (e.g., remain at P1 polarization) and pass through PSR 713a after which they reach second LCHWP 720b. In the OFF state, LCHWP 720b acts as a HWP that switches the polarization of rays (e.g., from P1 to P2 polarization). Therefore, rays 708 passing through OFF LCHWP 720b are reflected by PSR 713b toward the diffractive lens 707b where they are focused at a second focal length (e.g., a focal length of 0.5 mm). Similarly, by turning ON first and second LCHWPs 720a, 720b and turning the LCHWP 720c OFF, rays are re-directed toward diffractive lens 707c and are focused at a third focal length (e.g., a focal length of 0.75 mm).
The last scenario is when the first three LCHWPs 720a-c are in the ON state and the fourth LCHWP 720d is in the OFF state. Polarization of rays 708 is switched by the fourth LCHWP 720d and rays 708 are reflected by PSR 713d toward diffractive lens 707d where they are focused at a fourth focal length (e.g., a focal length of 1 mm). Thus, by turning ON and OFF selected LCHWP, rays 708 may be directed to a particular diffractive lens thereby focusing light at a selected focal length. While the OIIS 701b is capable of focusing light at four discrete values (e.g., focal lengths of 0.25 mm, 0.5 mm, 0.75 mm, and 1 mm), more or fewer focal lengths may be achieved by adding or removing one or more LCHWP, PSR, and diffractive lenses.
Fourth LCHWP 720d is shown disposed at an angle (e.g., approximately 45 degrees) relative to the fourth PSR 713d while first, second, and third LCHWPs 720a-c are disposed at an angle equal to that of the first, second, and third PSRs 713a, 713b, and 713c, respectively. The angle of LCHWPs relative to the PSR can be adjusted while achieving similar results depending on the design of LCHWP. In an alternative embodiment, the fourth LCHWP 720d may be removed and PSR 713d may be reoriented in such a way that the PSR 713d (e.g., the final PSR in the series) is cross-polarized relative to absorptive polarizer 714. The resulting OIIS has similar functionality to that of OIIS 701b, but with one fewer component. Similar to other embodiments disclosed herein, this configuration may be combined with other embodiments described herein to add more functionalities such as polarization resolved imaging or multispectral imaging.
Referring now to
Referring to
If the state of LCHWP 720a remains ON and LCHWP 720c is turned OFF, the polarization of the rays 708 will be switched to the orthogonal state (e.g., P2 polarization) by the LCHWP 720c before interacting with PSDL 716a. Because PSDL focuses light differently depending on polarization of the light, PSDL 716a will focus the P2 polarized rays 708 at a second focal length (e.g., f2=0.5 mm) that is different from the first focal length. PSDL 716a is designed in such a way that it focuses P1 polarization light at focal distance f1 and P2 polarization light at focal distance f2. P1 and P2 are two arbitrary chosen orthogonal states of linear polarization, but they may alternatively be circular or elliptical polarization while achieving an OIIS with the same functionality as OIIS 701c.
In a second scenario, LCHWP 720a is turned OFF, thereby causing the polarization of incoming rays 708 to switch into the orthogonal state (e.g., P2 polarization). P2 polarized rays 708 will pass through the PSR 713a and reach PSR 713b. The PSR 713b is oriented cross-polarized relative to PSR 713a; therefore, PSR 713b reflects the P2 polarized rays toward LCHWP 720b. When the LCHWP 720b is ON, it does not change the polarization of rays 708 (e.g., rays 708 maintain P2 polarization). The PSDL 716b will focus these rays at a third focal length (e.g., f3=0.75 mm). However, when LCHWP 720b is turned OFF, the LCHWP 720b will switch the polarization of impinging rays. Therefore, when LCHWP 720b is OFF, rays 708 switch to P1 polarization and PSDL 716b will focus the P1 polarized rays 708 at a fourth focal length (e.g., f4=1 mm) that is different from the third focal length. Thus, by appropriately changing the ON/OFF status of each LCHWP in the system and by utilizing polarization-selective diffractive lenses whose focal length is dependent on the polarization of incoming rays, an OIIS is achieved which has reconfigurable focal length using one or more input electric signals to the LCHWP components.
An OIIS with reconfigurable focal length is advantageous for depth imaging. In particular, an adjustable focal length can be used to obtain the best imaging quality at the depth of interest. In the case of illumination, the focal length may be selected to achieve the maximum intensity of light at a certain depth of tissue for therapeutic purposes or any other applications, such as tissue ablation or other laser surgical applications.
Integration of a sensor/detector 827 on the OIIS platform, which may receive feedback from the imaging/illuminating scene, is also contemplated herein. One example of a sensor is a depth sensor to measure the distance of the object to be imaged (e.g., an organ or tissue) from an OIIS to accordingly adjust its focal length or any other parameters. The adjustments may be made manually based on readings from the depth sensor or may be controlled automatically by a control module (not shown). Various electrical traces to one or more components in the OIIS, such as sensors, or electrically actuated LC-based components, may be included on substrates or other components within the OIIS. These traces are omitted from illustrations for clarity.
The components included in OIIS 801a or 801b may have an arbitrary angle with the substrate 805 as shown in
In
The foregoing description and figures are illustrative of various embodiments of the present invention and are not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been specifically described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this disclosure. Accordingly, many different embodiments stem from the above description and the drawings.
This application is a continuation-in-part of International Application No. PCT/US2022/029301, “Methods And Apparatus For Reconfigurable Optical Endoscopic Catheter,” filed May 13, 2022; which claims priority to U.S. Provisional Patent Application Ser. No. 63/189,053, “Methods and Apparatus for Reconfigurable Optical Endoscopic Catheter,” filed May 14, 2021. The subject matter of all of the foregoing is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63189053 | May 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2022/029301 | May 2022 | US |
| Child | 18508852 | US |
