Source: http://www.google.com/patents/US7343811?dq=5,222,134
Timestamp: 2014-09-22 01:25:21
Document Index: 403948778

Matched Legal Cases: ['art 24', 'art 25', 'arts 24', 'arts 24', 'art 25', 'art 24', 'art 24', 'art 32', 'art 32']

Patent US7343811 - Sensor and guide wire assembly - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsThe invention relates to a sensor (23) adapted for a sensor and guide wire assembly for intravascular measurements in a living body, wherein the sensor (23) comprises a pressure sensitive part (24) and an electronic part (25), said pressure sensitive part (24) comprising a first chip (26) provided with...http://www.google.com/patents/US7343811?utm_source=gb-gplus-sharePatent US7343811 - Sensor and guide wire assemblyAdvanced Patent SearchPublication numberUS7343811 B2Publication typeGrantApplication numberUS 11/359,761Publication dateMar 18, 2008Filing dateFeb 23, 2006Priority dateFeb 24, 2005Fee statusPaidAlso published asDE602006011380D1, EP1695659A1, EP1695659B1, US7263894, US20050268724, US20060207335Publication number11359761, 359761, US 7343811 B2, US 7343811B2, US-B2-7343811, US7343811 B2, US7343811B2InventorsLars Tenerz, Leif SmithOriginal AssigneeRadi Medical Systems AbExport CitationBiBTeX, EndNote, RefManPatent Citations (18), Non-Patent Citations (2), Referenced by (2), Classifications (25), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetSensor and guide wire assemblyUS 7343811 B2Abstract The invention relates to a sensor (23) adapted for a sensor and guide wire assembly for intravascular measurements in a living body, wherein the sensor (23) comprises a pressure sensitive part (24) and an electronic part (25), said pressure sensitive part (24) comprising a first chip (26) provided with at least one pressure sensitive device (27) and at least one piezoelectric element (35), and said electronic part (25) comprising a second chip (28) provided with at least one electric circuit, and wherein said pressure sensitive part (24) and electronic part (25) are spatially separated from each other and are electrically connected with at least one electrical lead (29).
the pressure sensitive part and the electronic part being spatially separated from each other and are electrically connected with at least one electrical lead and wherein the pressure sensitive part and the electronic part are attached to a flexible insulating board.
7. A sensor according to claim 1, wherein the element is a piezoelectric element.
8. A sensor and guide wire assembly being adapted for intravascular measurements in a living body and comprising a sensor, wherein the sensor comprises a pressure sensitive part and an electronic part;
said pressure sensitive part comprising a first chip provided with at least one pressure sensitive device and at least one piezoelectric, piezoresistive or piezocapacitive element;
9. A sensor and guide wire assembly according to claim 8, wherein at least one electrical connection line is arranged at the board to electrically connect the pressure sensitive part and the electronic part to each other.
10. A sensor and guide wire assembly according to claim 9, wherein the electronic part is arranged at a proximal portion of the sensor and guide wire assembly.
11. A sensor and guide wire assembly according to claim 9, wherein the electronic part is arranged in an external unit outside the living body.
FIELD OF THE INVENTION The present invention relates generally to sensor and guide wire assemblies, in which a sensor is mounted at the distal end of a guide wire for intravascular measurements of physiological variables in a living body, and in particular to the design and arrangement of the sensor.
BACKGROUND OF THE INVENTION Sensor and guide wire assemblies in which a sensor is mounted at the distal end of a guide wire are known. In U.S. Pat. No. Re. 35,648, which is assigned to the present assignee, an example of such a sensor and guide wire assembly is disclosed, where a sensor guide comprises a sensor element, an electronic unit, a signal transmitting cable connecting the sensor element to the electronic unit, a flexible tube having the cable and the sensor element disposed therein, a solid metal wire (also called a core wire), and a coil attached to the distal end of the solid wire. The sensor element comprises a pressure sensitive device, e.g. a membrane, with piezoresistive elements connected in a Wheatstone bridge-type of arrangement mounted thereon. An exemplifying electrical circuit arrangement can also be found in the present applicant's U.S. Pat. No. 6,343,514. As an alternative, the pressure sensitive device can also be in the form of a resonant structure, as is disclosed in the present applicant's U.S. Pat. Nos. 6,182,513 and 6,461,301. Instead of using cables to connect a sensor element to an electronic unit, other ways of receiving sensor signals can be employed. U.S. Pat. Nos. 6,615,067 and 6,692,446, which are assigned to the present assignee, disclose sensor systems for signal transmission via body tissues and passive biotelemetry, respectively.
In the U.S. application Ser. No. 10/611,661, which is assigned to the present assignee, a principally different solution is presented. Here it is the design of the sensor element itself�rather than the mounting arrangement and design of the core wire�that provides the resistance against bending artefacts. According to Ser. No. 10/611,661, a sensor element comprises a mounting base, which provides for the desired cantilevered mounting of the sensor element.
SUMMARY OF THE INVENTION These objects are achieved by a sensor and a sensor and guide wire assembly according to the independent claim(s). Preferred embodiments are set forth in the dependent claim(s).
A sensor and guide wire assembly comprises a sensor which, according to the prior art, is in the form of a generally rectangular and rather thin sensor chip with a pressure sensitive device provided thereon. The pressure sensitive device can be in the form of a membrane, which covers a small cavity in the upper side at a first end portion of the sensor chip and which has piezoresistive elements mounted thereon. According to the invention, this first portion is spatially separated from a second part of the sensor. A sensor thereby comprises a pressure sensitive part, which has a pressure sensitive device, such as a membrane, provided thereon, and at least one piezoresistive element mounted on the membrane. The second part of the sensor is also referred to as the electronic part, and includes, in a first embodiment of the invention, at least one electric circuit including at least one electric resistor and connection pads. In other embodiments of the invention, the electronic part can comprise a printed circuit with electronic logic and different signal processing elements. In a sensor and guide wire assembly, the first and second parts are spatially separated with, for example, a few millimeters and are electrically connected with at least one electric lead. The length of the pressure sensitive part�which is the part of a sensor that is potentially sensitive to bending artefacts�can thereby be reduced, which, in turn, makes it less sensitive to such bending artefacts. The length of the electronic part can, on the other hand, be increased, if this is desirable in order to incorporate more functionality in the electronic circuitry arranged thereon. Another advantage with physical division of the sensor in an electronic part and a pressure sensitive part is that these two parts easily can be manufactured by different techniques and even by different manufacturers.
The two parts are then electrically connected during the assembly of the sensor and guide wire assembly.
FIG. 4 illustrates a cross sectional view of the pressure sensor according to a preferred embodiment the present invention.
DETAILED DESCRIPTION OF THE INVENTION For better understanding of the context in which a sensor according to the present invention is going to be used, a sensor and guide wire assembly 1 of a conventional design is illustrated in FIG. 1. The sensor guide 1 comprises a hollow tube 2, a core wire 3, a first coil 4, a second coil 5, a jacket or sleeve 6, a dome-shaped tip 7, a sensor element 8, and one or several electrical leads 9. The proximal end of the first coil 4 is attached to the distal end of the hollow tube 2, while the distal end of the first coil 4 is attached to the proximal end of the jacket 6. The proximal end of the second coil 5 is connected to the distal end of the jacket 6, and the dome-shaped tip 7 is attached to the distal end of the second coil 5. The core wire 3 is at least partly disposed inside the hollow tube 2 such that the distal portion of the core wire 3 extends out of the hollow tube 2 and into the second coil 5. The sensor element 8 is mounted on the core wire 3 at the position of the jacket 6, and is through the electrical leads 9 connected to an electronic unit (not shown in the figure). The sensor element 8 comprises a pressure sensitive device in the form of a membrane 10 (not visible in the figure), which through an aperture 11 in the jacket 6 is in contact with a medium, such as blood, surrounding the distal portion of the sensor guide 1. As is well known in the art, the dimensions as well as other properties of guide wires adapted for introduction into the artery can vary considerable based on the type of procedure being performed, the particular patient, etc. The corresponding ranges of dimensions are also applicable to a sensor guide whose distal end is provided with a sensor element. In one conventional design of a sensor guide like the sensor guide 1 shown in FIG. 1, the diameter of the tube 2 is about 0.014 inches (0.36 mm) and the dimensions of element 8 are 1340�180�100 μm (length�width�height).
Although not shown in the figure, the sensor element 8 further comprises an electrical circuitry, which in a Wheatstone bridge-type of arrangement is connected to one or several piezoresistive elements provided on the membrane 10. As is well known in the art, a certain pressure exerted on the membrane 10 from the surrounding medium will thereby correspond to a certain stretching or deflection of the membrane 10 and thereby to a certain resistance of the piezoresistive elements mounted thereon and, in turn, to a certain output from the sensor element 8. It should therefore be clear that it is highly preferable that this output from the sensor element 8 does not change due to factors that are not related to a real change in the physical properties of the surrounding medium. As was mentioned above, one such factor is so-called bending artefacts, the source of which is that a bending of the sensor guide 1 is transferred to a deformation of the membrane 10. Here, the discussion above about piezoresistive elements coupled in a Wheatstone bridge-type of arrangement should only be seen as an illustrative exemplification; in short, the basic problem to be solved by the present invention is that a pressure sensitive device, such as a membrane, may be influenced by a bending of a sensor guide.
Another preferred embodiment is schematically illustrated in FIG. 4 showing a cross-sectional view of the pressure sensor. In the figure the pressure sensitive part 24 and the electronic part 25 are attached at a flexible insulating board 60. One or many electrical connection lines 62 are arranged at the board electrically connecting the two parts 24 and 25 to each other. These lines may e.g. be metallized strips at the surface of the board. The board is in turn attached to the core wire preferably in a recess in accordance with the above described embodiment. Communication between the two parts 24, 25 and an external unit, and power supply of the two parts, may be arranged by conventional electrical connections or wirelessly or a combination of electrical leads and wireless communication. This is schematically illustrated by the double-arrow 64.
The electronic part 25 may include all the different kind of circuitry, e.g. described in connection with the other embodiments, e.g. integrated CMOS, piezoelectric crystal connected to a piezocapacitive sensor at the sensor part 24, a temperature sensor, preferably based upon piezotechnology.
By using a board according to this embodiment it is considered that two main advantages are achieved. Firstly, the pressure sensitive part 24 is very efficiently protected against bending artefacts by the inherent flexibility of the board, and secondly, the electrical connection may be arranged in a very practical way, which reduces the manufacturing cost.
Furthermore, these advantages are also achieved if only the sensor part is arranged at the board 60. In that case the electronic part may be arranged at the core wire a predetermined distance from the board, alternatively the electronic part is arranged at a proximal portion of the sensor and guide wire assembly or even in an external unit outside the living body.
The external half 51 of the Wheatstone bridge comprises a first resistance 52 and a second resistance 53. The first resistance 52 is by an electrical lead 54 a connected to the connection pad 40 a of the electronic part 32, while another electrical lead 54 b connects the second resistance 53 to the connection pad 40 c. A positive excitation voltage E+is applied over the resistances 52 and 53, while a negative excitation voltage E−is applied directly to the connection pad 40 b of the electronic part 32. A voltage difference S (i.e. a signal), which represents the resistance of the piezoresistive element 35 and thereby the pressure that the surrounding medium exerts on the membrane 34, can thereby be obtained between the electrical leads 54 a and 54 b. It should, once again, be emphasized that the circuit arrangement described above is only an exemplifying arrangement. It is, for example, possible to provide a full Wheatstone bridge in a sensor according to the invention. In that case, the pressure sensitive part could comprise a piezoresistive element as described above, whereas the electronic part would include at least three resistors. In another arrangement, the pressure sensitive part could include also pressure insensitive resistors. A particular advantage with the present invention is the enhanced possibility to provide a more complex electrical circuit at an electronic part of a sensor. In that case, more sophisticated components, such as operational amplifiers, could be provided to improve the signal characteristics from the sensor. It is in particular possible that the electronic part comprises commercially available standard electronics, which, e.g., is provided as integrated circuits with the so-called CMOS technology. With a more sophisticated electrical circuit arrangement at the sensor side, the number of leads that connect a sensor to an external unit can be reduced, and even reduced to zero if a wireless signal transmission is employed. A wireless signal transmission is, for example, discussed in the above referenced patents. It is also possible to replace the piezoresistive element of the pressure sensitive part with another type of piezoelectrical component, for example a capacitive device which could be provided on the underside of a membrane and at the bottom of a recess, which is covered by that membrane, such that the capacitance of the capacitive device depends on the deflection of the membrane. The pressure sensitive device could also comprise a vibrating or resonating structure, whose vibration or resonance frequency is dependent on the pressure exerted by the ambient medium.
Although the present invention has been described with reference to a specific embodiment, also shown in the appended drawings, it will be apparent for those skilled in the art that many variations and modifications can be done within the scope of the invention as described in the specification and defined with reference to the claims below. It is, for example, possible to dispose an electronic part and a pressure sensitive part of a sensor in separate recesses in a core wire which is arranged inside a sensor and guide wire assembly. The invention can be used for intravascular measurements of other types of physiological variables such as temperature or flow, and is further applicable to direct as well as indirect measurements of such physiological variables.
Also, features of the above-described embodiment may be combined with features of the U.S. patents and patent applications discussed in the background section above as well as with features of U.S. provisional applications 60/577,197 (filed Jun. 7, 2004 by Lars Tenerz and Sauli Tulkki) and 60/605,170 (filed Aug. 30, 2004 by Sauli Tulkki). The entire contents of all of these patents and applications are incorporated herein by reference.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS1344758Sep 22, 1919Jun 29, 1920Donnelly JohnWindow-screenUS4463336 *Jun 24, 1983Jul 31, 1984United Technologies CorporationUltra-thin microelectronic pressure sensorsUS5029479 *Aug 15, 1988Jul 9, 1991Imo Industries, Inc.Differential pressure transducersUS5132658 *Apr 19, 1990Jul 21, 1992Sensym, Inc.Micromachined silicon potentiometer responsive to pressureUS6112598Jun 18, 1996Sep 5, 2000Radi Medical Systems AbPressure sensor and guide wire assembly for biological pressure measurementsUS6167763Apr 12, 2000Jan 2, 2001Radi Medical Systems AbPressure sensor and guide wire assembly for biological pressure measurementsUS6182513Dec 23, 1998Feb 6, 2001Radi Medical Systems AbResonant sensor and method of making a pressure sensor comprising a resonant beam structureUS6279402 *May 4, 2000Aug 28, 2001Applied Materials, Inc.Device for measuring pressure in a chamberUS6343514Jan 30, 1997Feb 5, 2002Radi Medical Systems AbCombined flow, pressure and temperature sensorUS6461301Mar 19, 2001Oct 8, 2002Radi Medical Systems AbResonance based pressure transducer systemUS6495908 *Oct 9, 2001Dec 17, 2002Siliconware Precision Industries, Co., Ltd..Multi-chip semiconductor packageUS6615067Mar 20, 2001Sep 2, 2003Radi Medical Systems AbMethod and device for measuring physical characteristics in a bodyUS6692446Mar 20, 2001Feb 17, 2004Radi Medical Systems AbPassive biotelemetryUS20030018273Sep 19, 2002Jan 23, 2003Jomed Inc.Guidewire with pressure and temperature sensing capabilitiesUS20050000294Jul 2, 2003Jan 6, 2005Radi Medical Systems AbSensor and guide wire assemblyUS20050011272Jul 18, 2003Jan 20, 2005Radi Medical Systems AbSensor and guide wire assemblyUSRE35648Jul 13, 1995Nov 4, 1997Radi Medical Systems AbSensor guide construction and use thereofEP1530028A1Jul 1, 2004May 11, 2005Festo CorporationMultiple technology flow sensor* Cited by examinerNon-Patent CitationsReference1C. Li et al., "Polymer Flip-Chip Bonding of Pressure Sensors on Flexible Kapton Film for Neonatal Catheters," Proceedings of IEEE, Oct. 24-27, 2004, pp. 749-752.2F. Sauser et al., "Pressure Microsensing Catheters for Neonatal Care," Sensors, Proceedings of IEEE, Oct. 24-27, 2004; pp. 1476-1479.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7967761Dec 1, 2006Jun 28, 2011Radi Medical Systems AbSensor and guide wire assemblyUS7994618 *Nov 14, 2006Aug 9, 2011Infineon Technologies AgSensor module and method for manufacturing same* Cited by examinerClassifications U.S. Classification73/756, 600/585International ClassificationA61M25/09, A61B5/0215, G01L9/00, G01L7/00, A61B5/00Cooperative ClassificationH01L2224/48091, H01L2224/48137, A61B5/6851, G01L9/06, A61B5/0215, A61M25/09, A61M2025/0166, G01L9/0022, A61M2025/09083, G01L19/142, G01L19/147European ClassificationA61B5/68D1F, G01L19/14C, G01L19/14E, G01L9/00A10E, G01L9/06, A61M25/09, A61B5/0215Legal EventsDateCodeEventDescriptionSep 8, 2011FPAYFee paymentYear of fee payment: 4May 30, 2006ASAssignmentOwner name: RADI MEDICAL SYSTEMS AB, SWEDENFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TENERZ, LARS;SMITH, LEIF;REEL/FRAME:017923/0792Effective date: 20060403RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google