Patent Application
20220354350
The invention relates to endoscopes, endoscope heads, and manufacturing techniques for endoscope heads. Endoscope heads within the scope of the present invention have particular application in disposable endoscopes.
Observation instruments such as endoscopes are used in medical and other applications to allow a visual inspection of locations that are not readily accessible. For example, endoscopes are used in medical applications to provide a view of an area within a patient's body. An endoscope typically includes an elongated shaft of relatively small diameter extending from a handle to a distal end. An imaging or viewing means included with the endoscope allows a user to obtain a view from the distal end. In many modern endoscopes, the imaging or viewing means includes an electronic imaging device (also referred to herein as an image sensor-based camera) mounted in a distal head at the distal end of the endoscope. Distal head materials are typically limited to materials such as stainless steel, ceramic or polyether ether ketone (PEEK), as these materials are robust enough to withstand the rigors of cleaning and reprocessing, such as hydrogen peroxide gas-plasma sterilization, necessary in the medical industry. The electronic imaging device of such an endoscope, often referred to as a video endoscope or a COTT (chip on the tip) endoscope, collects image data and communicates that data through the shaft and handle ultimately to a processing system that converts the collected data into an image to be displayed on a suitable display device.
To provide the desired illumination for the image to be collected, light may be generated by a light source either contained within the handle or connected thereto and directed through suitable conduits in the shaft (such as optical fibers for example) to the endoscope distal head where the light can be directed as desired through suitable lenses. Alternatively to relying on light conducted through the shaft to the distal end of the endoscope, a suitable light source such as an LED lamp may be placed at the distal head of the endoscope together with the electronic imaging device to provide the required illumination.
In addition to the imaging or viewing arrangement and the illumination arrangement, some endoscopes and similar instruments include a working channel which usually extends from the instrument handle through the elongated shaft to the distal head. This working channel comprises a passageway through which fluids may be introduced into the area under observation during the endoscopic procedure, or through which a suction may be applied. The working channel may also be used to insert tools into the area under observation for performing certain functions in the course of the endoscopic procedure.
The distal head of an endoscope may be constructed as a housing that receives the various components, namely, the electronic imaging device and associated optics and electronics, illumination components, and a portion of the working channel passageway. Although it is necessary to provide room in the distal head housing for the imaging device, illumination components, and working channel, the distal head of the instrument ideally has a cross-sectional dimension that remains as small as possible in order to facilitate insertion into narrow cavities, minimizing the invasiveness of the desired observation and other procedures intended for the instrument. This is true in general, but especially for medical applications. This requirement for a small cross-sectional dimension at the distal head makes fabrication challenging. Not only does the small size make the distal head housing itself more difficult to fabricate, but the small size also complicates the assembly of the various components in the distal head housing.
There remains a need for endoscope distal head structures that can accommodate all of the various endoscope head components desired for a given application and still be fabricated economically in a form that meets applicable size limitations. The desirability for more economical fabrication is particularly important for disposable endoscopes intended for only a single use.
An endoscope distal head (which may be referred to herein simply as a “distal head”) according to one aspect of the present invention includes a distal head housing defining a distal end surface of the distal head and being formed from a light-permeable material that is permeable to light at least within a securing material curing spectrum. The distal head housing defines a working channel tube receiving cavity, a camera receiving cavity, and an illumination light conduit receiving cavity. A working channel tube is secured within the working channel tube receiving cavity, while an image sensor-based camera assembly (which may be referred to as a “camera assembly”) is secured within the camera receiving cavity and an illumination conduit is secured within the illumination light conduit receiving cavity. Each of these components, the working channel tube, the camera assembly, and the illumination light conduit are each secured in their respective receiving cavity with a light-cured securing material that has been cured by exposure to light within the securing material curing spectrum.
The use of the light-permeable material to form the distal head housing allows all of the various components secured to the housing, namely, the working channel tube, camera assembly, and illumination light conduit to be readily secured in place with the light-cured securing material. As described further below, each of the components may be placed in the desired operating position within the respective receiving cavity together with a sufficient amount of light-curable securing material, that is, material that may be cured by exposure to light within the securing material curing spectrum. The light-curable securing material may then be cured, that is, converted to the light-cured securing material by directing light within the securing material curing spectrum through the distal head housing material. Thus, a distal head according to the first aspect of the invention provides additional options for fabrication of the device and these options may be particularly helpful in situations where the transverse dimension of the distal head must be small.
According to another aspect of the invention, an endoscope includes an elongated shaft having a distal end and a proximal end with an endoscope handle connected at the proximal end of the endoscope shaft and a distal head according to the first aspect of the invention connected at the distal end of the endoscope shaft. A working channel tube, camera assembly, and illumination light conduit are each secured in their respective receiving cavity within the distal head housing with light-cured securing material as described above in reference to the first aspect of the invention. The working channel tube extends through the shaft to a working channel access structure of the endoscope handle, while the illumination light conduit extends through the shaft to the endoscope handle where it is operably coupled to an illumination light source usually associated with the endoscope handle. The camera assembly is connected to a power and signal conduit arrangement that extends through the endoscope shaft to an operative connection within the endo scope handle.
Another aspect of the present invention encompasses methods of manufacturing a distal head for an endoscope. Methods according to this aspect of the invention include securing a distal head housing formed from a light-permeable material as described above in an assembly position. These methods then include placing a first endoscope head component such as the above-described camera assembly, working channel, or illumination light conduit in an operating position within a first component cavity within the distal head housing together with a light-curable securing material interposed between a surface of the first component cavity and an outer surface of the first endoscope head component. While the first endoscope head component is maintained in the operating position within the first component cavity with the light-curable securing material, methods according to this aspect of the invention further include directing light within the securing material curing spectrum through the light-permeable material of the distal head housing to the light-curable securing material. The light so directed cures the light-curable securing material to form the light-cured material and thereby secure the first endo scope head component in the operating position within the first component cavity.
Methods according to this third aspect of the invention encompass numerous variations. For example, some methods may include placing multiple different endoscope head components each within a respective component cavity formed in the distal head housing and each with the light-curable securing material interposed between the outer surface of the component and surface of the respective cavity. With multiple endoscope components thus positioned, the light within the securing material curing spectrum may be directed through the light-permeable material of the distal head housing to cure the securing material and thus secure the different components in place simultaneously. It is also possible within the scope of this third aspect of the invention to place a given endo scope head component and direct the appropriate curing light to secure the component in place one component at a time. Still further variations may place and secure a single component in place and place and secure multiple components in place either before or after securing the single component in place.
In implementations of an endoscope distal head according to any of the foregoing aspects of the invention, the light-permeable material from which the distal head housing is formed may be a material that is also permeable to light within a spectrum that includes an operating light spectrum for the camera assembly and the illumination light conduit. In these implementations the distal head may further include an illumination light spread lens located in the distal head housing with an inner face thereof facing and operatively aligned with an illumination light output of the illumination light conduit. Such an illumination light spread lens may comprise a plano-concave lens having a concave side comprising the inner face of the lens. The operating light spectrum for the camera assembly and the illumination light conduit may comprise the visible light spectrum for example.
Implementations of an endoscope distal head according to any of the forgoing aspects of the invention may use a plastic optical fiber as the illumination light conduit. Regardless of the specific form of the illumination light conduit, multiple such conduits may be desirable. In these cases, the distal head housing would include a respective illumination light conduit receiving cavity for each illumination light conduit, and each such conduit may be secured using the light-curable securing material.
The light-curable securing material employed according the any of the forgoing aspects of the invention may comprise a UV-curable epoxy which may be exposed to UV light to form the light-cured securing material. In this case the light-permeable material from which the distal head housing is formed is permeable to the UV spectrum or at least the applicable UV spectrum for the selected epoxy. In implementations where the distal head housing includes integral lenses formed from the light-permeable housing material, using a UV-curable material as the light-curable securing material would require that the light-permeable housing material would be permeable to both the operating light spectrum for given endo scope component and also the UV spectrum or applicable portion thereof.
These and other advantages and features of the invention will be apparent from the following description of representative embodiments, considered along with the accompanying drawings.
Referring to
Endoscope 100 receives electrical operating power through a cable 108. This power may be used to operate electronic components associated with distal head 106. Also, data signals from a camera assembly in distal head 106 may be communicated through appropriate pathways within shaft 101 and handle 102 to cable 108. In particular, a cable including a suitable number of electrical wires may extend from handle 102 through shaft 101 to the camera assembly contained within distal head 106. Data signals from the camera assembly may be communicated through cable 108 to processing equipment (not shown) that processes the image data and drives one or more video monitors to display the images collected at distal head 106.
Those familiar with endoscopic systems will appreciate that endoscope 100 includes a number of features such as controls 110 for controlling the operation of the endoscope and ports for introducing fluids or applying a suction to a working channel included in the endoscope. This particular endoscope shown is a flexible shaft endoscope and also has controls 113 for directing the end of the shaft. Example endoscope 100 includes ports 111 and 112 which are each in communication with a working channel extending from handle 102, through shaft 101, to distal head 106. Port 111 may comprise a coupling to allow a suction to be applied to the working channel or to allow fluids to be applied to the working channel. Port 112 may include an access opening through which an instrument may be inserted into the working channel. This working channel may be formed by a working channel tube which is not shown in
Both
As is common in camera assemblies for endoscopes, camera assembly 208, in addition to cover lens 212, includes camera body 222 and an electronic image sensor package 224 both shown in
Each of the distal head components, the camera assembly 208, each illumination light conduit 204a and 204b, and working channel tube 210 is received in a respective component receiving cavity formed within distal head housing 201. The various component receiving cavities are shown in several of the views but may perhaps most clearly be seen in the transverse section view of
The example distal head housing 201 shown in the drawings includes illumination light spread lenses integrally formed with the distal head housing 201 from the light-permeable material. A spread lens 236a associated with illumination light conduit 204a is best shown in
Each of the endoscope components, camera assembly 208, working channel tube 210, and illumination light conduits 204a and 204b are preferably secured in position within their respective receiving cavity. In accordance with the present invention, at least one such component, and preferably more than one, or all such components are secured in place with light-cured securing material as described above in the summary section. The section view of
The light-cured securing material may comprise a glue, adhesive, or other bonding material that bonds the respective component (camera assembly 208, working channel tube 210, or illumination light conduit 204a or 204b) to the surface forming the respective receiving cavity. The invention is not limited to any particular chemical or physical mechanism for providing the desired securing bond, however, to take advantage of the light-permeable nature of the material from which distal housing 201 is formed, the light-cured securing material according to the present invention is formed from a light-curable material that is cured when subjected to light within a spectrum to which the distal housing material is permeable. This use of light-curable securing material simplifies and reduces the time required to manufacture distal head 106, including enabling the ability for an assembler to visually inspect the assembly as it proceeds within the distal head, improving manufacturing precision thereby, as will be described below in connection with
Referring first to
Regardless of how the component or components are placed in their operating position with the light-curable securing material interposed between the component the respective receiving cavity surface, the method further includes directing light within the securing material curing spectrum through the light-permeable material of distal head housing 201 to the light-curable securing material to cure the material (form the light-cured material) to secure the given component in the desired operating position.
The section view of
Methods according to the present invention are not limited to any particular technique for placing the conduit in the operating position with the light-curable securing material interposed between the required surfaces. The light-curable securing material may be injected into a gap such as gaps 602 and 604 in
In the example distal head housing 201 shown in the figures, the method may include placing each of the components in their respective operating position in their receiving cavity together with the positioned light-curable securing material and then curing that material to secure each of those components in the desired operating position simultaneously. Alternatively, each component may be inserted to the desired operating position and the light-curable securing material placed according to the invention and then cured to secure only that component in its desired operating position. The process may then be repeated for each additional component to be secured in its respective operating position. In other implementations it may be desirable to place a subset comprising two or more of components in their desired operating position together with the light-curable securing material and then that light-curable securing material cured to secure those components. One or more additional components may then be placed and secured with the light-curable securing material. For example, particularly with distal head housing 201 shown in the present figures, in which the receiving cavities for the working channel tube and illumination light conduits are connected (via channels 234a and 234b in
The present invention may employ any light-curable securing material suitable for the given application. The primary requirement for the light-curable securing material is that it must be curable with light in a spectrum to which the distal head housing material is permeable. UV-curable epoxy may be used as the light-curable securing material where the distal head housing is formed from optically transparent polymers, such as acrylic. As discussed throughout the disclosure, these materials offer the distinct advantage over traditional endoscopic distal head materials in that they are transparent. Additionally, these materials are particularly useful when used in disposable endoscopic systems.
Distal head housings made from transparent polymers can be produced with a casting or mold injection process, which is not possible with some conventional materials. Also, the inventive distal heads described herein may be produced by 3D printing or other appropriate techniques. The ability to use these manufacturing techniques enables the integration of illumination spread lenses, discussed above, directly into the distal head, obviating, thereby the difficult process of inserting spread lenses into a machined piece, and enabling the inventive use of POFs as illumination conduits rather than much more expensive conventional optical fibers.
As discussed above, the NA of POF is generally much smaller than that of a conventional fiber bundle, resulting in a much smaller illumination cone. For example, a POF with a typical NA of 0.6 might have an illumination cone of only about 74 degrees, far below the typical endoscopic field of view of from 90-140 degrees. However, the present invention enables, as discussed above, the integration of spread lenses into the distal tip material itself, along with the illumination light conduit receiving cavity. Thus, an integrated spread lens can modify the effective NA of our example POF to 0.95, corresponding to an illumination cone of 145 degrees, making, thereby, the use of POFs practical for illumination conduits. As disposable scopes are single use in nature, they are not need to be required to survive the rigors of repeated chemical cleaning and/or autoclaving, and therefore need not be made from more robust materials such as stainless steel or PEEK. The present invention therefore enables the use of less expensive materials, more conducive to single-use systems, as well as overcomes problems associated with use of non-biocompatible materials, such as POFs.
The example of
As used herein, whether in the above description or the following claims, the terms “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, that is, to mean including but not limited to. Also, it should be understood that the terms “about,” “substantially,” and like terms used herein when referring to a dimension or characteristic of a component indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude variations therefrom that are functionally similar. At a minimum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.
Any use of ordinal terms such as “first,” “second,” “third,” etc., in the following claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another, or the temporal order in which acts of a method are performed. Rather, unless specifically stated otherwise, such ordinal terms are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term).
The term “each” may be used in the following claims for convenience in describing characteristics or features of multiple elements, and any such use of the term “each” is in the inclusive sense unless specifically stated otherwise. For example, if a claim defines two or more elements as “each” having a characteristic or feature, the use of the term “each” is not intended to exclude from the claim scope a situation having a third one of the elements which does not have the defined characteristic or feature.
The above-described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art without departing from the scope of the present invention. For example, in some instances, one or more features disclosed in connection with one embodiment can be used alone or in combination with one or more features of one or more other embodiments. More generally, the various features described herein may be used in any working combination.
