The present invention is further described in the detail description which follows, in reference to the noted plurality of drawings, by way of non-limiting examples of preferred embodiments of the present invention, in which like characters represent like elements throughout the several views of the drawings, and wherein:
The present invention will be described below with reference to the embodiments shown in the drawings.
The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.
The endoscope system may include an endoscope 10, a processor 30, and a monitor 40. The endoscope 10 may be detachably connected to the processor 30, and a suitable optical fiber, such as a single-mode optical fiber 12, extends through the endoscope 10. A monitor 40 is connected to the processor 30.
A laser unit 32 is provided in the processor 30, and is configured to emit a laser beam. Irradiated light enters an incident surface 121 of the optical fiber 12. The optical fiber 12 is configured to guide or direct the light from the proximal end to the distal end 10A of the endoscope 10. Light passing through the optical fiber 12 exits from the tip portion of the endoscope 10, so that an observed portion or surface is illuminated. Light reflected off the observed portion or surface enters a plurality of photo-detectors 14, and image-pixel signals are successively read from the photo-detectors 14 to by an image signal processing circuit 34 in the processor 30. In the image signal processing circuit 34, the signals are subjected to various processes to generate image signals. The generated image signals are fed to the monitor 40, so that the object image is displayed on the monitor 40. A controller 36 controls a piezoelectric actuator 16 provided at the distal end 10A of the endoscope 10.
In the distal end 10A of the endoscope 10, a 2-D piezoelectric actuator 16 is disposed and mounted to the fixed plate 17. The optical fiber 12 may extend through the actuator 16 and the distal end 12A of the optical fiber 12 may be held by the actuator 16. As shown in
The distal end 12A of the optical fiber 12 may project from the actuator 16 so that the distal end 12A becomes a fixed-free cantilever. The actuator 16 may be of any suitable type, such as a tube-shaped piezoelectric actuator. Further, such a piezoelectric actuator 16 may be composed of any suitable type of piezoelectric materials, such as PZT. The piezoelectric actuator 16 may be deformed by an inverse piezoelectric effect, thereby two-dimensionally driving the distal end 12A of the optical fiber 12. Namely, the piezoelectric actuator 16 may vibrate the distal end 12A along two axes perpendicular to each other while modulating or amplifying amplitudes of the vibration, so as to scan the distal tip portion 12P in spiral patterns. Thus, light irradiated from the distal tip 12P via the lens 19 may be scanned over the observed portion in the spiral pattern(s).
Light reflected from the observed portion passes through the lens 19 and the plurality of photo-detectors 14 collects the reflected light. Consequently, signals corresponding to the detected light are read from the photo-detectors 14 in a time-series, and are fed to the image signal processing circuit 34 shown in
The single-mode optical fiber 12 may be formed of any suitable material, such as a silica core and silica cladding. Further, a suitable covering may also be provided, for example a metallic or plastic covering, such as nylon sheet. The diameter D of the optical fiber 12 may be set to a range between a few hundred microns and a few millimeters. The optical fiber 12 has an etched-region 12D, in which the cross-sectional area or diameter is reduced. The tip portion 12P of the optical fiber 12 is not etched and remains at the diameter D. The etched-region may be configured by the fabricating process described below. Reducing the diameter at the etched-region 12D enables the distal end 12A of the optical fiber 12 to vibrate in the second resonance mode (See
With reference to
The pattern-formed silicon wafer 50 may be subjected to a development process and an etching process, such as an anisotropy-etching process. In this manner, a groove RB configured to support the distal end 12A of the optical fiber 12 is formed on the area RA. The groove RB may be of any suitable shape, such as a V-shaped groove. After the etching process, the silicon wafer 50 may be subjected to a deep reactive ion etching (RIE) process from the back surface, so that an aperture 52 is formed through the wafer 50. The aperture 52 may be of any suitable shape, such as rectangular, and divides the groove RB into a groove R1 and a groove R2. The groove R1 is configured to support the tip portion 12P of the optical fiber 12, and the groove R2 is configured to support a remaining distal end portion 12A of the optical fiber 12. The dimensions of the aperture 52 may correspond to those of the etched-region 12D of the optical fiber 12.
A fiber holder can also be configured to hold a plurality of optical fibers 12 for batch fabrication. In this regard, a silicon wafer 50 may include a plurality of parallel grooves RB for holding a plurality of parallel optical fibers 12. Further, a plurality of optical fibers 12 may extend across a single aperture 52 of a silicon wafer 50. Alternatively, a separate aperture 52 may be provided in the silicon wafer 50 for each of the grooves RB and optical fibers 12.
The distal end 12A of the optical fiber 12 may be coated with any suitable material, such as a metal material, for example chromium, by any suitable process, such as vapor deposition or sputtering. Two silicon wafers 50′ manufactured by the process shown in
The optical fiber 12 fastened to the fiber-holder 60 may be exposed, such as by immersion, in a suitable metal etchant, such as a chromium etchant. In this manner the chromium coating the etching portion (to be formed into the etched-region 12D) is etched and removed from the etching portion of the optical fiber (see
Subsequently, the optical fiber 12 fastened to the fiber-holder 60 may be exposed, such as by immersion, in a suitable etching solution 71, as shown in
A suitable actuator, such as a linear actuator (not shown), may be connected to the optical fiber 12 to enable the optical fiber 12, and particularly the distal end 12A, to be shifted or reciprocated along its longitudinal axis during exposure to the etching solution.
The optical fiber 12 may be exposed (or immersed) in the vessel 70 such that part of the etching portion (to be formed into the etched-region 12D) is located in the etchant 74. Further, the optical fiber 12 may be gradually and intermittently moved along the longitudinal direction so as to form a required profile of the etched-region 12D, or the total of the distal end 12A. As shown in
After the etching process, the optical fiber 12 may be detached from the actuator. Then the optical fiber 12 may be detached from the holder 60 in a suitable manner, such as by using resist stripper or sulfuric acid. To remove the chromium covering the optical fiber 12, the optical fiber 12 may be exposed, such as by immersion in chromium etchant. Thus, the fabricated optical fiber 12 may be completed, as shown in
In this way, the distal end 12A of the optical fiber 12 is gripped between the fiber-holder 60, which is composed of the two silicon wafers 50′ and has the aperture 52, and is fastened or clamped to the fiber-holder 60 by using the adhesive agent 53. The optical fiber 12 is immersed into the etching solution 71 with the etchant 74. The fiber-holder 60 functions as a weight or load during the etching process, and the fiber-holder 60 has symmetry or balance with respect to the held optical fiber 12. Therefore, the optical fiber 12 is stable while the distal end 12A is submerged in the etching solution 71, and the distal end 12A including the tip portion 12P does not vibrate or swing (even if the etchant solution 71 is disturbed during immersion of the optical fiber 12 in the etching solution, such as by moving the optical fiber 12 along the longitudinal direction). Thus, the operator can precisely or correctly measure the diameter “d” and the length “LD” of the etched-region 12D and the profile of the etched-region 12D during the etching process. Consequently, the distal end 12A of the optical fiber 12 is finely and precisely configured so as to realize the vibration in the second resonant mode.
Further, since the etched-region 12D is exposed through the aperture 52 to the exterior of the fiber-holder 60, and the tip portion 12P is sealed within the fiber-holder 60, the cross-sectional area of the optical fiber 12 is reduced at only the etched-region 12D, and the other portion, especially the cross-sectional area of the tip portion 12P, is not reduced while submerging the optical fiber 12 in the etching solution and moving the optical fiber 12 along the longitudinal direction.
As for the etching solution 71, another suitable etchant can be used instead of the HF acid solution. Further, another suitable etch-proof solvent can be used instead of fluorinated oil, and another suitable organic solvent can be used instead of iso-octane solvent. Further, the etching solution 71 may consist of only etchant, or any other suitable combination of solutions. Another suitable metallic or plastic material can be used to coat the optical fiber, instead of chromium.
Optionally, the position of the optical fiber 12 in the vessel 70 may be fixed throughout the etching process. In this case, the depth of the etchant layer 74 may be varied or adjusted to control the etching process. An optional profile of the optical fiber can be realized by the etching process according to the present embodiment. Therefore, the profile of the etched-region that allows the optical fiber to vibrate in first resonant mode or multi-resonant mode (for example, third resonant mode) can be determined. Further, another optical fiber, such as multi-mode optical fiber, can be used in the etching process.
Optionally, the optical fiber can be fastened to the fiber-holder using another method instead of adhesion. Optionally, a fiber-holder that is not etched by the etching solution, and that is capable of sealing the optical fiber, can be utilized, instead of the fiber-holder 60 described above. For example, a one-piece fiber-holder having a long and narrow hole can be prepared in advance, and the optical fiber can be installed into the hole and fasten to the fiber-holder. The configuration of the fiber-holder may be defined such that the etched-region is exposed outside of the fiber-holder. Also, a fiber-holder composed of another material, such as sapphire, which is impervious and resist-durable to the etchant solution, can be used, instead a fiber-holder composed of silicon wafer. In the case of sapphire, the fiber-holder can be manufactured by a sandblasting. The present invention can also be implemented in other applications other than endoscopy, such as microscopy and confocal microscopy. Finally, it will be understood by those skilled in the arts that the foregoing description is of preferred embodiments of the device, and that various changes and modifications may be made to the present invention without departing from the spirit and scope thereof.
It is further noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to a preferred embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.
The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.
One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.
The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
Although the invention has been described with reference to several exemplary embodiments, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified. Rather, the above-described embodiments should be construed broadly within the spirit and scope of the present invention as defined in the appended claims. Therefore, changes may be made within the metes and bounds of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the invention in its aspects.