Compact binocular image capture device

A binocular image capture device includes a plurality of stacked circuit boards, a front-facing dual image sensor mounted to a first circuit board of the plurality of stacked circuit boards, and signal conditioning electronics mounted to one or more of the plurality of stacked circuit boards and coupled to receive electrical signals generated by the dual image sensor. The dual image sensor is enclosed in a hermetic housing. In some examples, the hermetic housing may be formed by the first circuit board, a transition ring secured to the first circuit board, and an optics mount secured to the transition ring. In some examples, the hermetic housing may be formed using materials having matching coefficients of thermal expansion. In some examples, the binocular image capture device is enclosed by a shaft, the plurality of stacked circuit boards being stacked along a length of the shaft.

TECHNICAL FIELD

The present disclosure is directed to image capturing devices for conducting an image-guided procedure and more particularly to a compact binocular image capturing device for conducting an image-guided procedure.

BACKGROUND

Medical robotic systems such as teleoperational systems used in performing minimally invasive surgical procedures offer many benefits over traditional open surgery techniques, including less pain, shorter hospital stays, quicker return to normal activities, minimal scarring, reduced recovery time, and less injury to tissue. Consequently, demand for such medical teleoperational systems is strong and growing.

Examples of medical teleoperational systems include the da Vinci® Surgical System and the da Vinci® S™ Surgical System from Intuitive Surgical, Inc., of Sunnyvale, Calif. Each of these systems includes a surgeon's consoler a patient-side cart, a high performance three-dimensional (“3-D”) vision system, and Intuitive Surgical's proprietary EndoWrist® articulating instruments, which are modeled after the human wrist. When added to the motions of manipulators holding the surgical instruments, these articulating instruments allow at least six degrees of freedom of motion to their end effectors, which is comparable to or even greater than the natural motions of open surgery. During the performance of a medical procedure, it is useful to view two or three dimensional live images of the surgical site captured by an image capturing device. The image capturing device is sterilized by an autoclave cleaning process prior to being used during the medical procedure.

Accordingly, it would be advantageous to provide an image capturing device that supports binocular imaging in a compact form factor that is compatible with autoclave cleaning.

SUMMARY

The embodiments of the invention are best summarized by the claims that follow the description.

In some examples, a binocular image capture device may include a plurality of stacked circuit boards, a front-facing dual image sensor mounted to a first circuit board of the plurality of stacked circuit boards, and signal conditioning electronics mounted to one or more of the plurality of stacked circuit boards and coupled to receive electrical signals generated by the dual image sensor. The dual image sensor is enclosed in a hermetic housing.

In some examples, a binocular image capture device may include a first circuit board and a second circuit board arranged in a tombstone configuration such that the second circuit board is mounted to first circuit board at a perpendicular angle, a front-facing dual image sensor mounted to the first circuit board, and signal conditioning electronics mounted to the second circuit board and coupled to receive electrical signals generated by the dual image sensor. The dual image sensor is enclosed in a hermetic housing.

In some examples, a method for assembling a binocular image capture device may include securing a dual image sensor to a first circuit board, securing a signal conditioning electronics to one or more second circuit boards, stacking the first circuit board and the one or more second circuit boards to electrically couple the dual image sensor and the signal conditioning electronics, and sealing the dual image sensor in an autoclave-tolerant hermetic housing.

DETAILED DESCRIPTION

FIG. 1illustrates, as an example, a top view of an operating room in which a medical teleoperational system100is being utilized by a Surgeon20for performing a medical procedure on a Patient40who is lying down on an operating table50. One or more Assistants30may be positioned near the Patient40to assist in the procedure while the Surgeon20performs the procedure teleoperatively by manipulating control devices108,109on a surgeon console10.

In the present example, a bundled unit300of medical devices is inserted through a single entry port150into the Patient40. The bundled unit300may be used in a single-port system. Although the entry port150is a minimally invasive incision in the present example, in the performance of other medical procedures, it may instead be a natural body orifice. The bundled unit300is held and manipulated by a teleoperational arm assembly200(also “arm200”). Although only one teleoperational arm assembly is used in the present example, the medical teleoperational system100is equipped with additional teleoperational arm assemblies128,129which are swung out of the way during the performance of the present medical procedure, because they are not being used.

The console10includes a 3-D monitor104for displaying a 3-D image of a surgical site to the Surgeon, left and right manipulatable control devices108,109, a foot pedal105, and a processor102. The control devices108,109may include any one or more of a variety of input devices such as joysticks, gloves, trigger-guns, hand-operated controllers, or the like. The processor102may be a dedicated computer integrated into the console10or positioned next or near to it, or it may comprise a number of processing or controller components that are distributed in a distributed processing fashion throughout the system100.

The console10is usually located in the same room as the Patient so that the Surgeon may directly monitor the procedure, is physically available if necessary, and is able to speak to the Assistant(s) directly rather than over the telephone or other communication medium. However, it will be understood that the Surgeon can also be located in a different room, a completely different building, or other remote location from the Patient allowing for remote surgical procedures.

As shown inFIG. 3, the bundled unit300may include two surgical instruments or tools338,339and an image capturing device340(also “image capturing unit340”). Each of the surgical tools338,339is associated with one of the control devices108,109. The Surgeon performs a medical procedure by manipulating the control devices108,109so that the processor102causes corresponding movement of their respectively associated surgical tools338,339, while the Surgeon views the surgical site in 3-D on the console monitor104as it is captured by the image capturing device140.

Preferably, control devices108,109will be provided with at least the same degrees of freedom as their associated tools338,339to provide the Surgeon with telepresence, or the perception that the control devices108,109are integral with the tools338,339so that the Surgeon has a strong sense of directly controlling the tools338,339.

Preferably, the monitor104is positioned near the Surgeon's hands so that it will display a projected image that is oriented so that the Surgeon feels that he or she is actually looking directly down onto the operating site. To that end, images of the tools338,339preferably appear to be located substantially where the Surgeon's hands are located.

In addition, the real-time image is preferably projected into a perspective image such that the Surgeon can manipulate the end effectors322,332of the tools338,339through their corresponding control devices108,109as if viewing the workspace in substantially true presence. By true presence, it is meant that the presentation of an image is a true perspective image simulating the viewpoint of an operator that is physically manipulating the tools338,339. Thus, the processor102transforms the coordinates of the tools338,339to a perceived position so that the perspective image is the image that one would see if the image capturing device140was located directly behind the tools338,339.

The processor102performs various functions in the system100. One important function that it performs is to translate and transfer the mechanical motion of control devices108,109to the teleoperational arm assembly200through control signals over bus110so that the Surgeon can effectively manipulate the tools338,339.

Although described as a processor, it is to be appreciated that the processor102may be implemented in practice by any combination of hardware, software and firmware. Also, its functions as described herein may be performed by one unit or divided up among different components, each of which may be implemented in turn by any combination of hardware, software and firmware. Further, although being shown as part of or being physically adjacent to the console10, the processor102may also comprise a number of subunits distributed throughout the system such as in printed circuit boards installed in the patient side cart120and/or the teleoperational arm assemblies128,129,200, as well as, or alternatively to, the console10.

For additional details on the construction and operation of various aspects of a medical teleoperational system such as described herein, see, e.g., commonly owned U.S. Pat. No. 6,493,608 “Aspects of a Control System of a Minimally Invasive Surgical Apparatus,” and commonly owned U.S. Pat. No. 6,671,581 “Camera Referenced Control in a Minimally Invasive Surgical Apparatus,” which are incorporated herein by reference.

FIG. 2illustrates, as an example, a simplified side view (not necessarily to scale or complete) of the teleoperational arm assembly200which is holding the bundled unit300of medical devices. A tool guide270is inserted through the minimally invasive incision comprising the entry port150in the Patient in this example, and coupled to the teleoperational arm assembly200by a guide holder240. The bundled unit300may then be inserted into the Patient through the tool guide270. The teleoperational arm assembly200is mechanically supported by a base201of the patient side cart120.

Links202,203are coupled together and to the base201through horizontal setup joints204,205. The setup joints204,205in this example are passive joints that allow manual positioning of the arm200when their brakes are released. For example, setup joint204allows link202to be manually rotated about axis206, and setup joint205allows link203to be manually rotated about axis207.

Although only two links and two setup joints are shown in this example, more or fewer of each may be used as appropriate in this and other teleoperational arm assemblies in conjunction with the present invention. For example, although setup joints204,205are useful for horizontal positioning of the arm200, additional setup joints may be included and useful for limited vertical and angular positioning of the arm200. For major vertical positioning of the arm200, however, the arm200may also be slidably moved along the vertical axis of the base201and locked in position.

The teleoperational arm assembly200also includes two active joints and a number of gears driven by motors. A yaw joint210allows arm section230to rotate around an axis261, and a pitch joint220allows arm section230to rotate about an axis perpendicular to that of axis261and orthogonal to the plane of the drawing. An interface302comprises mating parts on the carriage245and the proximal end of the bundled unit300such as motor driven gears that actuate movement of the surgical tools338,339and image capturing unit340through conventional joints, cable and pulley systems.

The arm section230is configured so that sections231,232are always parallel to each other as the pitch joint220is rotated by its motor. As a consequence, the bundled unit300may be controllably moved by driving the yaw and pitch motors so as to pivot about the pivot point262, which is generally located through manual positioning of the setup joints204,205so as to be at the point of entry into the Patient. In addition, the bundled unit300is coupled to a carriage245on the arm section230which in turn is coupled to a linear drive mechanism to extend or retract the bundled unit300along its insertion axis263.

Although each of the yaw joint210, pitch joint220and motor driven gears in the carriage245is controlled by an individual joint or gear controller, the controllers may be controlled by a common master/slave control system so that the medical devices of the bundled unit300may be controlled through user (e.g., Surgeon or operator) manipulation of its associated control device.

FIG. 3illustrates, as an example, a perspective view of a distal end of the bundled unit300. The bundled unit300includes removable surgical tools338,339for performing a medical procedure and a removable image capturing unit340for viewing the procedure at a surgical site within a patient. Each of the tools338,339and image capturing unit340extends through a separate lumen formed in an inner core of the bundled unit300. Replacement of one or both of the surgical tools338,339during or in preparation for performing a medical procedure may then be accomplished by the Assistant removing the tool that is no longer needed from its lumen and replacing it with a substitute tool131from a tray60by inserting the substitute tool131in the vacated lumen. Alternatively, if unused lumens are available, an additional tool may be inserted through one of those available lumens without removing any other tools already in place.

The image capturing device340preferably includes a stereoscopic pair of cameras342,343(and/or a single binocular camera) for three-dimensional imaging of the surgical site and an illuminating device344such as a light emitting diode (LED) or a fiber optics bundle carrying light from an external source, to enhance visibility of objects in the captured images. Auxiliary image capturing units, such as an ultrasound probe, may also be provided in available lumens of the bundled unit300for “seeing” into anatomic structures for surgical or diagnostic purposes.

In some embodiments, an overtube310is also included in the bundled unit300for protecting its inner core and the medical devices (i.e., surgical tools and image capturing units) inserted therethrough. The overtube310may be rigid. Alternatively, it may be formed of flexible material or comprise actively and/or passively bendable sections so that the bundled unit300may conform to the shapes of body lumens as it moves therethrough to a surgical site within a patient.

The surgical tools338,339each have a controllably extendable, rotatable, and bendable arm to which their respective end effectors322,332are coupled to by wrist mechanisms323,337. For example, the arm of the surgical tool339comprises three links331,333,335coupled by distal joints334,336. The proximal link335is controllably extendable and retractable along an insertion axis352(which is preferably parallel to the insertion axis263of the bundled unit300), and is controllably rotatable (as shown by rotation angle353) about the insertion axis352. The middle link333, on the other hand, is controllably bendable by distal joint336relative to the link335(as shown by bend angle351), and the distal link331is coupled to the links333,335and bendable by distal joint334so that its bend angle354is in an opposite direction as that of the link333and consequently, keeps links331,335in parallel alignment.

The arm of the surgical tool338is similarly constructed as that of the surgical tool339. Additional details for one example of the wrist mechanisms323,337are provided in commonly owned U.S. Pat. No. 6,817,974 “Surgical Tool Having Positively Positionable Tendon-Actuated Multi-Disk Wrist Joint,” which is incorporated herein by this reference.

The image capturing device340also has a controllably extendable, rotatable, and bendable arm345that facilitates at least insertion/retraction of the image capturing unit340along its insertion axis (which may be parallel to the insertion axis263of the bundled unit300) and pitch motion in order to achieve a sufficient elevation of the image capturing device340“above” the surgical tools338,339so as to properly view them during a surgical procedure. Additional degrees of freedom, such as roll angular movement of the image capturing device340about its insertion axis, may also be provided in order to facilitate additional positioning and orientation capabilities for the image capturing device340. For enhanced maneuverability, the image capturing arm345may also be bendable such as the controllably bendable, rotatable, and extendable arms of the surgical tools338,339.

FIGS. 4A and 4Bare simplified diagrams of a binocular image capturing device400with a front-facing sensor according to some embodiments. According to some embodiments consistent withFIGS. 1-3, image capturing device400may be used to implement image capturing device340of bundled unit300. According to some embodiments, binocular image capturing device400may be used in systems other than bundled unit300. In particular, image capturing device400is well-suited for imaging applications that demand small feature size, ruggedness, and ability to withstand autoclaving. For example, binocular image capture device400may be used in medical instruments such as medical teleoperational systems, and/or handheld endoscopes. While binocular image capture device400may be particularly well-suited for medical imaging applications, binocular image capture device400may also be used in general imaging applications, such as photography and/or video applications of mobile devices.

According to some embodiments, binocular image capture device400includes one or more features that facilitate a small feature size and/or a compact design. In some examples, the diameter ‘d’ of binocular image capture device400may be less than 10 mm. In some examples, the aspect ratio (i.e., the ratio between the length ‘l’ and the diameter ‘d’) of binocular image capture device400may be less than 10:1.

As depicted inFIGS. 4A and 4B, binocular image capturing device400acquires binocular images from a perspective of forward-looking out of a distal end of an elongate device. In some embodiments, the elongate device may be an endoscope capable of being inserted into an anatomical port and/or anatomical passageway for acquiring images during a medical procedure. Consistent with such embodiments, binocular image capturing device400may be positioned at the distal tip of an endoscope.

A shaft410fully or partly encloses components of binocular image capturing device400. In some examples, shaft410may correspond to an 8.8 mm endoscope shaft, in which case the diameter ‘d’ of shaft410is 8.8 mm. More generally, the diameter ‘d’ of shaft410is sufficiently small to accommodate insertion/retraction of binocular image capturing device400through anatomical ports and/or anatomical passageways. According to some embodiments, shaft410may be formed using a rigid tube. In some embodiments, shaft410may be flexible. Although depicted as having a circular cross-section, it is to be understood that the cross-section of shaft410may be ellipsoidal, polygonal, and/or any other suitable shape. In some examples, the diameter and/or the shape of shaft410may vary along the length of shaft410. Although components of binocular image capturing device400are generally disposed within shaft410, some components may protrude from the sides of shaft410and/or out of the distal end of shaft410.

An optional illumination module420provides illumination from the distal end of binocular image capturing device400. In some embodiments, binocular image capturing device400is used to capture scenes with little or no ambient illumination, such as interior anatomical cavities and/or passageways. Consequently, illumination module420serves as the primary source of illumination to the scene in support of image acquisition. In some embodiments, illumination module420may include one or more illumination sources, such as light emitting diodes (LEDs). In some examples, the illumination source may include a ring of LEDs to increase the brightness and uniformity of the illumination. In some embodiments, the illumination source may be external to illumination module420, in which case illumination module may include passive optical components, such as fiber optic lines, lenses, mirrors, and/or the like. For example, illumination module420may include one or more fiber optic lines to route illumination received from the proximal end of binocular image capture device400around the components binocular image capture device400and out the distal end. As depicted inFIGS. 4A and 4B, illumination module420includes two such fiber optic lines disposed on opposite sides of shaft410to provide uniform illumination intensity to the scene.

Binocular optics module430receives illumination (i.e., light and/or other electromagnetic signals) from the scene and projects a pair of images onto a dual image sensor440. Binocular optics module430may include one or more lenses, mirrors, apertures, filters, prisms, polarizers, and/or the like to achieve desired image characteristics (e.g., focal length and/or spectral characteristics). One or more components of binocular optics module430may be adjustable so as to vary the image characteristics (e.g., to vary the focal length).

Dual image sensor440generally includes any device suitable for converting the pair of projected images from binocular optics module430into analog and/or digital electrical signals that retain at least a portion of the information contained in the projected images. According to some examples, dual image sensor440may include a charge coupled device (CCD) sensor, active pixel sensor, complementary metal oxide semiconductor (CMOS) sensor, N-type metal oxide semiconductor (NMOS) sensor and/or the like. According to some embodiments, dual image sensor440may include a single monolithic sensor with dual active areas, and/or may include a plurality of discrete sensors.

In general, it is desirable for the active area of an image sensor, such as dual image sensor440, to be as large as possible to improve image quality. For instance, relative to a small image sensor, a large image sensor may have more pixels for improved resolution and/or larger pixels for improved sensitivity. However, because binocular image capture device400has a small diameter ‘d’ (e.g., 10 mm or less), the space available for an image sensor is generally constrained, particularly in the direction of the diameter. One way to increase the area of an image sensor while satisfying the space constraints of binocular image capture device400is to mount the image sensor in a sideways-facing configuration. In the sideways-facing configuration, one edge of the image sensor lies along the length of binocular image capture device400and therefore is not subject to the diameter constraints. However, the sideways-facing configuration is problematic for several reasons. First, in order to project images onto a sideways-facing image sensor, binocular optics module430is tasked with redirecting light from the distal end of image capture device400by 90 degrees. This generally increases the complexity and/or cost of the binocular optics module430and may degrade image quality. Second, although in some instances a sideways-facing image sensor may be used for monocular imaging applications, the sideways-facing image sensor is even more challenging to integrate in binocular imaging applications. Especially given the space constraints of binocular image capture device400, projecting a pair of images onto a sideways-facing image sensor may involve substantial additional complexity and cost. Thus, a sideways-facing image sensor may not be well-suited for use in binocular image capture device400.

In order to address these challenges, dual image sensor440of binocular image capture device400is configured as a front facing image sensor, with an active area that is oriented towards the distal end of binocular image capture device400. In the front facing configuration, binocular optics module430may be simplified, cheaper, and/or more compact relative to a sideways-facing configuration because the projected images are not redirected by 90 degrees and because there is little additional complexity involved in binocular imaging applications relative to monocular imaging applications.

In order to increase the active area of dual image sensor440in the front-facing configuration while satisfying the diameter constraints of shaft410, the shape of dual image sensor440may be adapted to conform to the cross-sectional shape of shaft410. For example, when shaft410has a circular cross-section, an octagon shape conforms better to shaft410than a rectangular shape. Accordingly, dual image sensor440may have an octagonal shape, as may be formed by sawing or cleaving the corners off of a rectangular sensor.

In some embodiments, dual image sensor440may be disposed in a hermetic housing442. Hermetic housing442protects dual image sensor440from moisture and/or other contaminants. Moreover, hermetic housing442is mechanically robust to the temperature cycles experienced during autoclave cleaning. Although hermetic housing442is depicted as encapsulating dual image sensor440, it is to be understood that other components of binocular image capture device400may also be hermetically sealed in hermetic housing442. Embodiments of hermetic housing442are described in greater detail below with reference toFIGS. 5-7.

In some examples, the electrical signals generated by dual image sensor440have a relatively small signal amplitude. In particular, due to their low amplitude, the electrical signals may not be suitable for transmission over long distances, e.g., from the distal end to the proximal end of a teleoperational arm assembly. Accordingly, dual image sensor is electrically coupled to a conditioning module450, which receives the electrical signals generated by dual image sensor440and converts them for transmission. In some examples, conditioning module450may include signal conditioning electronics including one or more image signal processors (ISPs), amplifiers, analog to digital (A/D) converters, image encoders, and/or the like. In some examples, the output of conditioning module450may be a digital video signal feed. The digital video signal feed (or another signal representation of captured image data) is transmitted out of binocular image capture device400via a connector460. In some examples, connector460is configured to transmit image data and to receive power and/or control signals.

To improve image quality, components of conditioning module450are generally positioned in close physical proximity to dual image sensor440. This prevents or mitigates the degradation of the electrical signals generated by dual image sensor440over long transmission lines. This also facilitates a compact, simple, and robust design. In some examples, an image signal processor of conditioning module450may be disposed on the backside of dual image sensor440(i.e., a “flip-chip” configuration). In some examples, the image signal processor and dual image sensor440may be mounted on opposite sides of a circuit board such that electrical signals generated by dual image sensor440are routed a short distance through the circuit board (e.g., a few mm or less). In some examples, the image signal processor and/or other components of conditioning module450may be mounted in a “tombstone” configuration relative to dual image sensor440, as described in greater detail below with reference toFIGS. 5 and 6. In some examples, conditioning module450may be mounted in a “stacked” configuration relative to dual image sensor440, as described in greater detail below with reference toFIG. 7.

During operation, electronic components of binocular image capture device400(which may include various components of illumination module420, dual image sensor440, conditioning module450, and/or connector460) generate waste heat. A thermal management module470is optionally used to conduct the waste heat away from binocular image capture device400to prevent overheating. In some embodiments, thermal management module470may include a heat sink that is thermally coupled to one or more components of binocular image capture device400. In some examples, the heat sink may be configured to conduct heat in a proximal direction away from binocular image capture device400. In some examples, thermal management module470may include thermally conductive paste applied at various locations throughout binocular image capture device400. However, in some embodiments, binocular image capture device400may not include thermal management module470. Specifically, the compact design of binocular image capture device400may provide sufficient thermal conduction to prevent overheating without a dedicated thermal management module470.

FIGS. 5A and 5Bare simplified diagrams of a binocular image capture device500in a tombstone configuration according to some embodiments. In some embodiments consistent withFIGS. 1-4, binocular image capture device500may be used to implement at least some of the features of binocular image capture device400.

Binocular image capture device500is fully or partially encased by an outer tube502. A pair of fiber optic lines504are potted along upper and lower portions of outer tube502. Although depicted as being located at a distal end of binocular image capture device500for clarity, outer tube502and/or fiber optic lines504may extend along the length of binocular image capture device500. According to some embodiments consistent withFIGS. 1-4, outer tube502and fiber optic lines504may correspond to shaft410and illumination module420, respectively.

A dual image sensor510with an octagonal in-plane shape is disposed in a forward-facing configuration (i.e., oriented towards a distal end of binocular image capture device500). Dual image sensor510is mounted on a circuit board512. According to some embodiments, dual image sensor510may be wire bonded to circuit board512. In some examples, circuit board512may be a ceramic circuit board to provide a temperature and/or moisture resistant backing for dual image sensor510. In some examples, circuit board512may be formed using another material with low (or zero) moisture penetration and/or high thermal conductivity.

A transition ring514is affixed to circuit board512. In some examples, transition ring514may be a kovar ring that is affixed to circuit board512by brazing. In some examples, transition ring514may be formed using another material with a coefficient of thermal expansion (CTE) that matches the CTE of circuit board512and/or that is compatible with processes such as brazing, welding, gluing, and/or the like.

An optics housing516is affixed to transition ring514. In some examples, optics housing516may be a stainless steel housing that is affixed to transition ring514by welding (e.g., laser welding). In some examples, the stainless steel housing may be formed using alloys such as 17-4 stainless steel and/or 440 stainless steel to match the CTE of circuit board512, transition ring514, and/or optical glass. In some examples, optics housing516may enclose binocular optics, such as binocular optics module430. Binocular optics are not depicted inFIGS. 5Aof5B for clarity, but may extend from the distal end of binocular image capture device in some embodiments. According to some embodiments, cover glass518may be affixed to a rim520of transition ring514. For example, cover glass518may be affixed to transition ring514by glue.

According to some embodiments consistent withFIGS. 1-4, circuit board512, ring514, optics housing516, and/or cover glass518may form a hermetically sealed chamber corresponding to hermetic housing442. The hermetically sealed chamber encloses dual image sensor510and/or optical components (e.g., binocular optical module430) disposed within optical housing516. According to some embodiments, the hermetically sealed chamber may be filled with an inert gas (e.g., nitrogen) to reduce or prevent condensation or other contamination of dual image sensor510and/or the optical components contained in optical housing516. Advantageously, the hermetically sealed chamber of binocular image capture device500is formed using materials with matching CTE (e.g., ceramic circuit board512, kovar transition ring514, stainless steel optics housing516, and optical glass used in binocular optics and/or cover glass518) to reduce distortions and/or stress caused by thermal cycling during autoclave cleaning.

A circuit board532may include various signal conditioning electronics, such as an image signal processor530, hosts electronics534, and/or connector536. Image signal processor530is coupled to receive electronic signals from dual image sensor510and generate digital image data based on the received electronic signals. The digital image data (e.g., a digital video feed) is output via connector536. Electronics534may include one or more capacitors, resistors, diodes, oscillators, sensors (e.g. temperature sensors), and/or the like. In some examples, circuit board532may be a ceramic circuit board in order to improve tolerance to autoclave cleaning and/or harsh operating environments such as the human body. In some examples, circuit board532may be an FR-4 circuit board and/or any other suitable type of circuit board.

Circuit board532is mounted to circuit board512in a tombstone configuration. In the tombstone configuration, the edge of circuit board532abuts the backside of circuit board512at a right angle. As depicted inFIGS. 5A and 5B, circuit board532is mounted at approximately the vertical center of circuit board512. In some examples, circuit board532may be rigidly affixed to circuit board512. In some examples, circuit board532may be in direct contact with circuit board512and/or may be glued to circuit board512. According to some embodiments consistent withFIGS. 1-4, the components mounted to circuit board532may correspond to conditioning module450and/or connector460.

A heat sink540is coupled to circuit board532and/or circuit board512via a support member542. Heat sink540configured to sink heat away from electronic components mounted to circuit board532and/or circuit board512. Advantageously, the tombstone configuration provides access to a large surface area on the backside of circuit board532to maximize heat transfer from components mounted to the front side to heat sink540. In some examples, heat sink540may be a copper heat pipe. In general, however, the CTE of copper does not match the CTE of a ceramic circuit board. Accordingly, support member542may be formed using a transition material that matches the CTE of ceramic, such as a Cu—Mo and/or Cu—W alloy. Consistent with such embodiments, support member542may be affixed to circuit board532and/or circuit board512by brazing. According to some embodiments consistent withFIGS. 1-4, heat sink540and/or support member542may correspond to thermal management module470.

FIGS. 6A and 6Bare simplified diagrams of a binocular image capture device600in a tombstone configuration with a flip-chip image signal processor according to some embodiments. According to some embodiments consistent withFIGS. 1-4, binocular image capture device may be used to implement at least some features of binocular image capture device400.

Like binocular image capture device500ofFIGS. 5A and 5B, binocular image capture device600includes a tube602, fiber optic lines604, a dual image sensor610, a circuit board612, a transition ring614with a rim620, an optics housing616, cover glass618, an image signal processor630, a circuit board632, electronics634, a connector636, a heat sink640, and a support member642. In some examples, image signal processor630, electronics634, and/or connector6236may be used as signal conditioning electronics. These features generally correspond to similarly labeled features ofFIGS. 5A and/or 5B.

Unlike image signal processor530, which is mounted to circuit board512, image signal processor630is disposed in a flip-chip configuration on the back side of dual image sensor610. Advantageously, the flip-chip configuration of image signal processor630reduces the distance that electrical signals generated by dual image sensor610propagate to reach image signal processor630, which improves image quality. Moreover, the flip-chip configuration reduces the number of discrete components because the dual image sensor610and image signal processor630are on the same chip. This reduces the complexity of binocular image capture device600. Unlike other approaches to integrate dual image sensor610and image signal processor630on a single chip (e.g., a system-on-chip configuration with dual image sensor610and image signal processor630on the same side of a chip), the flip-chip configuration does not reduce the active area of dual image sensor610.

FIGS. 7A-Eare simplified diagrams of a binocular image capture device700in a stacked configuration according to some embodiments. According to some embodiments consistent withFIGS. 1-4, binocular image capture device may be used to implement at least some features of binocular image capture device400.

Like binocular image capture devices500and600, binocular image capture device700includes a tube702, fiber optic lines704, a dual image sensor710, a circuit board712, a transition ring714with a rim720, an optics housing716, cover glass718, an image signal processor730, a circuit board732, electronics734, a connector736, a heat sink740, and a support member742. In some examples, image signal processor730, electronics734, and/or connector736may be used as signal conditioning electronics. These features generally correspond to similarly labeled features ofFIGS. 5 and 6. As depicted inFIG. 7, image signal processor730is mounted to the back side of circuit board712.FIG. 7depicts several features that are not shown inFIGS. 5 and 6. For example, binocular image capture device700includes a heat sink extension744coupled to heat sink740by a threaded connector746.

FIG. 7depicts circuit boards712and732arranged in a stacked configuration. Optionally, the stacked configuration of circuit boards may include one or more additional circuit boards750to increase the total available circuit board area for components such as electronics734and/or connector736. Advantageously, arranging the circuit boards in a stacked configuration may improve the compactness of binocular image capture device700. Furthermore, although binocular image capture device700is depicted as including heat sink740, the stacked configuration may offer sufficient heat conduction that heat sink740(and associated components such as support member742and heat sink extension744) may be omitted.

To facilitate stacking, circuit boards712,732and/or750may have the same or similar in-plane shape and dimensions. In some examples, circuit boards712,732, and/or750may have aligned bonding pads752to create one or more electrical contacts between adjacent circuit boards. That is, bonding pads on the front or distal side of a particular circuit board are lined up with bonding pads on the back or proximal side of a neighboring circuit board. In some embodiments, portions of the stacked circuit boards may be recessed relative to bonding pads752to form a gap between neighboring circuit boards in which to fit mounted components. Although the stack of circuit boards depicted inFIG. 7includes three circuit boards712,732, and750, it is to be understood that the stack of circuit boards may include any number of circuit boards.

According to some embodiments, adjacent circuit boards in the stack of circuit boards may be directly coupled to one another and/or coupled using an adhesive. Coupling between adjacent circuit boards facilitates heat transfer along the length of the stack of circuit boards, as one or more of the stacked circuit boards may not have a direct connection to heat sink740. In some examples, electrical and/or mechanical contact between bonding pads752of adjacent circuit boards may be formed using solder, conductive epoxy, metal bonding (e.g. brazing, sintering, welding, and/or the like), anisotropic conductive film (ACF), anisotropic conductive paste (ACP), and/or the like.

Additionally or alternatively, adjacent circuit boards in the stack of circuit boards may be separated by gaps, such as air gaps. For example, a gap may be provided to accommodate large devices mounted to a circuit board, to allow the stack to bend, and/or the like. In this regard, the stacked configuration may include stacking circuit boards712,732and/or750in any suitable arrangement with facing planar surfaces, with or without direct physical contact between adjacent circuit boards.

To facilitate hermeticity, mechanical integrity, and/or efficient heat transfer in binocular image capture device700, abutting components of binocular image capture device700may be affixed using brazing (see, e.g., brazed interfaces770) and/or welding (see, e.g., welded interfaces772) techniques. In some examples, welded interfaces772may be laser welded. As depicted inFIG. 7c, examples of brazed interfaces770include the interfaces between heat sink740and support member742; support member742and circuit board750; and circuit board712and transition ring714. Examples of welded interfaces772include the interfaces between transition ring714and optics housing716; optics housing716and binocular optics760; and between optics housing716and endpiece762. The interface between endpiece762and windows764is a soldered interface774. For example, windows764may be affixed to endpiece762using window solder. While specific embodiments have been described, it is to be understood that a variety of other techniques may be used to form interfaces between components, such as glass fritting, epoxy potting, sintering, adhesives, and/or the like.

FIG. 8is a simplified diagram of a method800for fabricating a binocular image capture device according to some embodiments. According to some embodiments consistent withFIGS. 1-7, method800may be used to assemble binocular image capture device400,500,600, and/or700. According to some embodiments, method800may be used to assemble the binocular image capture device in a tombstone configuration consistent withFIGS. 5 and/or 6or in a stacked configuration consistent withFIG. 7. According to some embodiments, the binocular image capture device assembled using method800may be very compact, having a diameter of no more than 10 mm and/or an aspect ratio of no more than 10:1. According to some embodiments, the binocular image capture device assembled using method800may be compatible with autoclave cleaning. For example, components that are sensitive to moisture may be hermetically sealed to withstand steam treatment, and components that abut one another may have matching coefficients of thermal expansion to withstand thermal cycling.

At a process805, a first circuit board and one or more second circuit boards are fabricated. According to some embodiments, the first circuit board and/or the one or more second circuit boards may be ceramic circuit boards. When assembling the binocular image capture device in the stacked configuration, the first circuit board and/or the one or more second circuit boards may have approximately the same in-plane shape and/or dimensions. Moreover, the first circuit board and/or the one or more second circuit boards may have may have aligned bonding pads to allow electrical connections between adjacent circuit boards in the stack. Still further, the first circuit board and/or the one or more second circuit boards may have recessed portions to fit electronic components in the stacked configuration.

At a process810, a transition ring is secured to the first circuit board. According to some embodiments, the transition ring may be a kovar ring with a coefficient of thermal expansion matched to that of ceramic. According to some embodiments, the transition ring may be secured to the first circuit board by brazing.

At a process815, a dual image sensor is secured to the first circuit board. According to some embodiments, the dual image sensor may be a monolithic image sensor with dual active areas. According to some embodiments, the dual image sensor may have an octagonal shape to increase the fill factor relative to a rectangular shape when placed in a circular tube. According to some embodiments, the dual image sensor may be secured to the first circuit board by wire bonding and/or any other suitable integrated circuit packaging technique.

In some examples, the binocular image capture device may include signal conditioning electronics, such as an image signal processor, electronic devices, and/or the like. At a process820, an image signal processor is secured to the first circuit board or the one or more second circuit boards. According to some embodiments, the image signal processor may be disposed on the back side of the dual image sensor in a flip-chip configuration, in which case process820merges with process815(i.e. securing the dual image sensor and the image signal processor is accomplished during the same steps). According to some embodiments, the image signal processor may be secured to the back side of the first circuit board opposite the dual image sensor. Such embodiments may reduce the distance between the image signal processor and the dual image sensor to facilitate low noise operation. According to some embodiments, the image signal processor may be secured to the one or more second circuit boards (i.e., on a different circuit board than the dual image sensor). Although there is a greater distance between image signal processor and the dual image sensor, such embodiments may reduce the distance between the image signal processor and a heat sink to facilitate heat transfer. According to some embodiments, the image signal processor may be secured to the first circuit board or the one or more second circuit boards by wire bonding and/or any other suitable integrated circuit packaging technique.

At a process825, electronic devices are secured to the one or more second circuit boards. According to some embodiments, the electronic devices may include one or more resistors, capacitors, inductors, diodes, sensors (e.g., temperature sensors), oscillators, power converters, and/or the like. According to some embodiments, the electronic devices may supply electrical signals to the dual image sensor and/or the image signal processor (e.g., clock signals and/or power signals). According to some embodiments, the electronic devices may condition electrical signals received from the dual image sensor and/or the image signal processor (e.g., the electronic devices may include one or more amplifiers, filters, level shifters, and/or the like for signal conditioning). According to some embodiments, the electronic devices may be secured to the one or more second circuit boards by soldering, wire bonding, and/or the like.

At a process830, a support member is secured to the one or more second circuit boards. According to some embodiments, the support member may be a copper alloy (e.g., Cu—Mo or Cu—W) to facilitate later connection of a copper heat sink that is not CTE matched with ceramic circuit boards. When assembling the binocular image capture device in the stacked configuration, the support member may be secured to the most proximal circuit board in the stack. When assembling the binocular image capture device in the tombstone configuration, the support member may be secured to the back side of the one or more second circuit boards opposite the electronic devices and/or the image signal processor. According to some embodiments, the support member may be secured to the one or more second circuit boards by brazing.

At a process835, a connector is secured to the one or more second circuit boards. According to some embodiments, the connector may be configured to transmit captured image data and to receive power and/or control signals. When assembling the binocular image capture device in the stacked configuration, the connector may be secured to the most proximal circuit board in the stack. When assembling the binocular image capture device in the tombstone configuration, the connector may be secured at a proximal end of the one or more second circuit boards. According to some embodiments, the connector may be secured to the one or more second circuit boards by soldering.

At a process840, the first circuit board and the one or more second circuit boards are assembled in the stacked configuration or the tombstone configuration. When assembling the binocular image capture device in the stacked configuration, electrical contact between the stacked circuit boards is created by aligning the bonding pads and forming conductive contacts using techniques such as ACF, ACP, solder, sintered metal paste, and/or the like. Adhesive may be applied between adjacent circuit boards to improve mechanical integrity and/or heat transfer along the length of the stacked circuit boards. When assembling the binocular image capture device in the tombstone configuration, the one or more second circuit boards are mounted against the back side of the first circuit board and with a perpendicular orientation relative to the first circuit board.

At a process845, an optics mount is secured to the transition ring. According to some embodiments, the optics mount may include a stainless steel assembly. According to some embodiments, the stainless steel assembly may be formed from a stainless steel alloy with a coefficient of thermal expansion that matches that of ceramic and/or optical glass, such as 17-4 or 440 stainless steel. According to some embodiments, the optic mount may be secured to the transition ring by welding (e.g., laser welding).

At a process850, binocular optics are assembled. According to some embodiments, the binocular optics are aligned to form a pair of images on the dual image sensor to facilitate 3-dimensional imaging applications. According to some embodiments, the binocular optics include a pair of substantially identical optical assemblies to form each of the pair of images. According to some embodiments, the binocular optics are mounted to the optics mount. In some examples, the binocular optics may be mounted within the optics mount and/or may protrude from the optics mount. According to some embodiments, the binocular optics may include cover glass to cover and/or seal the dual image sensor. According to some embodiments, the cover glass may be glued to a rim of the transition ring and/or the optics mount.

At a process855, an end piece is secured to the optics mount. According to some embodiments, the end piece may include a stainless steel assembly with similar material properties to the optics mount. According to some embodiments, the end piece may include windows, such as plated sapphire windows. In some examples, the windows may be soldered to the stainless steel assembly of the end piece. According to some embodiments, the end piece may be secured to the optics mount by welding (e.g., laser welding). According to some embodiments, securing the end piece to the optics mount may cause a hermetic seal to form around the binocular optics and/or the dual image sensor. Consequently, process855may be performed in a purged environment to prevent moisture and/or contaminants from entering the hermetically sealed volume during the assembly process. For example, process855may be performed in an inert gas environment (e.g., nitrogen gas).

At a process860, fiber optics are assembled. According to some embodiments, the fiber optics may be potted along one or more channels running along an upper and lower portion of the binocular image capture device. Consequently, the potted fiber optics may have a hemicylindrical shape bounded by the curved surface of binocular image capture device on one side and the flat surface of the packed components of binocular image capture device on the other.

At a process865, a heat sink is assembled. According to some embodiments, the heat sink may include a copper heat pipe. In some examples, the copper heat pipe may be secured to the support member by brazing and/or by welding. According to some embodiments, the heat sink may include a heat sink extension that is coupled to the copper heat pipe by a threaded attachment.

At a process870, the assembled binocular image capture device of processes805-865is secured to a shaft. According to some embodiments, the shaft may be a metal tube that fully or partly encloses the binocular image capture device. According to some embodiments, the shaft may be an 8.8 mm endoscope shaft. According to some embodiments, the shaft is secured by welding (e.g., laser welding) to one or more portions of the binocular image capture device. For example, the shaft may be welded to the end piece. According to some embodiments, thermally conductive paste may be applied between the shaft and the first ceramic board and/or the one or more second ceramic boards to facilitate heat dissipation through the shaft. Such embodiments may be particularly useful when the binocular image capture device does not include a dedicated heat sink (e.g., when processes830and/or865are omitted from method800).