Ultra miniature pressure sensor

• US 6,976,965 B2
• Filed: 09/19/2002
• Issued: 12/20/2005
• Est. Priority Date: 09/02/1994
• Status: Expired due to Fees

• Current Assignee: Volcano Corporation (Koninklijke Philips N.V.)
• Original Assignee: Volcano Corporation (Koninklijke Philips N.V.)
• Inventors: Ortiz, John E., Obara, Robert Z., Corl, Paul D.
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US10/247,043
• Publication Number:
  US 20030040674A1
• Time in Patent Office: 1,188 Days
• Field of Search: 600/486, 600/488
• US Class Current: 600/486
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61M 2025/0002 with a pressure sensor at the distal end
• CPC Class Codes: A61M 2025/09008 having a balloon
• CPC Class Codes: A61M 2025/09083 having a coil around a core
• CPC Class Codes: A61M 25/09 Guide wires
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 19/149 of immersion sensor, e.g. where the sensor is immersed in the measuring medium or for in vivo measurements, e.g. by using catheter tips
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm

Abstract

A guide wire having pressure sensing capabilities for measuring the pressure of liquid in a vessel comprising a flexible elongate member and having proximal and distal extremities and having an outside diameter of 0.018″ or less. The distal extremity of said flexible elongate member is adapted to be disposed in the liquid in said vessel. A housing is carried by the flexible elongate member and has a diameter substantially the same as the diameter of the flexible elongate member. The housing has a space therein with a pressure sensor mounted in the space in the housing. The pressure sensor has a diaphragm that is sensitive to changes of pressure in the liquid in the vessel. The diaphragm is rectangular in shape and is bordered by a rim surrounding the well. A backing plate is formed of an insulating material bonded to the crystal and serves to reinforce the rim of the crystal of semiconductor material. The backing plate has a cavity therein underlying the diaphragm and is in substantial registration with the diaphragm. The cavity serves to provide a pressure reference.

Claims

1. A pressure sensor apparatus comprising:

a guidewire;

a sensor housing having an external wall, a lumen, and a hole in the external wall extending from an external surface of the sensor housing to the lumen and being open to ambient fluid, the sensor housing disposed near a distal extremity of the guidewire;

a first coil disposed proximally from the sensor housing;

a second coil comprising a radiopaque material and disposed distally from the sensor housing; and

a solid state pressure sensor having a pressure sensitive region located at or near one end thereof, the solid state pressure sensor mounted within the sensor housing such that the pressure sensitive region projects into the lumen of the sensor housing without contacting the external wall of the sensor housing and such that a portion of the pressure sensitive region is disposed opposite the hole and is in fluid communication with the ambient fluid via the hole.

2. The pressure sensor apparatus of claim 1, wherein the solid state pressure sensor is mounted within the sensor housing using an elastic medium.

3. The pressure sensor apparatus of claim 2, wherein the elastic medium is an epoxy.

4. The pressure sensor apparatus of claim 1, wherein the pressure sensitive region includes a pressure sensitive diaphragm.

5. The pressure sensor apparatus of claim 1, wherein the guidewire has an outside diameter of 0.018″

or less.

6. The pressure sensor apparatus of claim 1, wherein the solid state pressure sensor comprises a diaphragm structure supported by a base plate.

7. The pressure sensor apparatus of claim 1, further comprising a core wire extending from a proximal extremity of the guidewire, through the sensor housing, and to the distal extremity of the guidewire.

8. The pressure sensor apparatus of claim 7, wherein the core wire comprises a tapered distal extremity.

9. The pressure sensor apparatus of claim 1, wherein the lumen is filled with a viscous fluid.

10. The pressure sensor apparatus of claim 9, wherein the viscous fluid comprises an oil.

11. The pressure sensor apparatus of claim 9, wherein the hole has a diameter configured to hold the viscous fluid within the lumen and prevent bleeding of the viscous fluid into the ambient fluid.

12. The pressure sensor apparatus of claim 1, wherein the hole has a diameter of approximately 5 mils or less.

13. The pressure sensor apparatus of claim 1, comprising a temperature sensitive resistor disposed on a distal extremity of the guidewire.