Patent Application
20100026456
1. Field
Embodiments of the invention relate to the field of radio frequency identification (RFID), and more specifically, to radio frequency identification of RFID tags that are located close to an RFID receiver while rejecting RFID tags that are slightly further away.
2. Background
Robotic surgical systems allow surgeons to perform minimally invasive surgery using endoscopic instruments that are controlled by robotic manipulators. Such systems may allow a more intuitive use of the instruments by translating camera views and surgeon hand movements to correspond to what the surgeon would expect in an open surgery.
Typically a robotic surgical system provides a small number of robotic manipulators, perhaps three or four, to which a variety of surgical instruments may be attached. The surgical instruments may be changed during the course of a surgery. The robotic manipulators are typically wrapped with a sterile drape that provides a sterile barrier between the robotic manipulators and the attached surgical instruments.
The robotic surgical system may need to know the identity of the attached instruments so the system can provide the appropriate translation of the camera views and surgeon hand movements. The system may provide information about the identity of the attached instruments to the surgeon to maintain awareness of the current configuration of the system. In some cases, the instruments may be capable of attachment in more than one orientation. The robotic surgical system may need to know the orientation of the attached instruments so the system can provide the appropriate translation of the camera views and surgeon hand movements.
It would be desirable to provide identification of a surgical instrument attached to a surgical robot and separated by a sterile barrier. It would also be desirable to provide the orientation of the surgical instrument.
A radio frequency identification (RFID) tag is embedded on a surgical instrument and a radio frequency identification (RFID) reader is provided on a surgical robot to allow identification of the attached surgical instrument. The RFID tag includes an RFID circuit assembly, a first pot core half, and a first toroidal wire coil that fits within the first pot core half and is electrically coupled to the RFID circuit assembly to modulate received radio frequency (RF) energy. The RFID reader includes an RFID transceiver circuit, a second pot core half, and a second toroidal wire coil that fits within the second pot core half and is electrically coupled to the transceiver circuit to transmit RF energy and receive modulated RF energy from the first wire coil only when the first pot core half is substantially aligned with and proximate to the second pot core half.
Other features and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below.
The invention may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention by way of example and not limitation. In the drawings, in which like reference numerals indicate similar elements:
In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known devices, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.
The robotic surgical instruments 102, 104, 106, 108, 110 are detachably coupled to surgical robots on the patient side cart 100. The surgical robots may provide motive forces to the surgical instruments to position them and to operate end effectors on the instruments. The surgical robots may receive information from the instruments such as the amount of force being applied by the instrument. In particular, the patient side cart 100 may support an endoscopic camera system 102, 104.
The endoscopic camera system includes a camera 102 and an endoscope 104. The camera may be located on the non-sterile side of the sterile barrier. The camera may include image sensors, focusing optics, and light sources. The endoscope 104 may be coupled to a mating portion 210 of the camera 102 with the sterile barrier separating them. The camera 102 may provide two image ports 213, 214 that are coupled to the image sensors to form stereoscopic images. The camera 102 may provide illumination from the light sources at the two light ports 211, 212.
The endoscope 104 includes a shaft 200 that can be inserted through an incision to place a distal end 202 of the endoscope 104 adjacent a surgical site. The endoscope 104 may provide a passive extension of the camera 102 into the surgical site. Lenses at the distal end 202 of the endoscope 104 may relay surgical images to camera ports 223, 224 that are coupled to the image ports 213, 214 on the camera 102. Light from the light ports 211, 212 on the camera 102 may be coupled to light receivers 221, 222 on the endoscope 104. Light pipes may convey the light from the light receivers 221, 222 to the distal end 202 of the endoscope to illuminate the surgical site.
A radio frequency identification (RFID) tag 225 is embedded on the proximal end 220 of the surgical instrument 104. A radio frequency identification (RFID) reader is provided within the endoscopic camera 102 to allow identification of the attached endoscope 104 from its RFID tag 225. The RFID tag 225 and an antenna 215 of the RFID reader are of a unique construction to allow the antenna and/or tag to be embedded in a metal structure that may be used to form the mating portion 210 of the camera 102 and/or the proximal end 220 of the endoscope 104. The structure of the RFID tag 225 and antenna 215 permit reliable operation in what may be an electrically noisy environment. For example, there may be electrical interference created by high voltage discharges from electrocautery devices in close proximity to the RFID tag 225.
The RFID tag 225 of the present invention includes a toroidal wire coil 302 that fits within half of a pot core 310. The pot core half 310 has a cylindrical base 306 with a cylindrical center pole 308 and a cylindrical outer pole 304 extending from a first side of the base. The pot core half 310 may be constructed of ferrite or other material with a high magnetic permeability that does not maintain a significant magnetic field when an external field is removed. The toroidal wire coil 302 fits within the outer pole 304 of the pot core and around the center pole 308. The toroidal wire coil 302 may be potted in the pot core half 310.
The two ends 402, 404 of the toroidal wire coil 302 are electrically coupled to an RFID circuit assembly 406 to modulate received radio frequency (RF) energy. The RFID circuit assembly 406 is powered by the received RF energy. The RFID circuit assembly 406 is configured to encode identification information in the transmitted RF energy by load modulation which may allow the surgical robot to identify the surgical instrument and confirm that it is attached. The two ends 402, 404 of the toroidal wire coil 302 may extend through one or more gaps 408 in an outer pole of the pot core half 310 as shown in
The pot core half 310 of the RFID tag 225 and the pot core half 700 of the RFID antenna 215 will be configured with the open faces 300, 702 adjacent one another and separated by no more than a small distance, typically about 0.05 inch and generally less than 0.15 inch, such that a sterile barrier may be placed between them. The adjacent coils 302, 706 will be largely enclosed by the bases 306, 704 and outer poles 304, 714 of the two pot core halves 310, 700 which may shield the coils from nearby electrical interference. The substantial alignment of the poles of the two pot core halves 310, 700 may increase the electrical coupling of the adjacent coils 302, 706 and increase the signal strength while decreasing the noise coupling to improve the signal to noise ratio.
In some applications the surgical instrument 104, 106, 108, 110 may be installed in more than one orientation. For example, the endoscope 104 illustrated in
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. The description is thus to be regarded as illustrative instead of limiting.
