Airway adaptor with optical pressure transducer and method of manufacturing a sensor component

• US 20070273887A1
• Filed: 05/22/2007
• Published: 11/29/2007
• Est. Priority Date: 05/25/2006
• Status: Active Grant

• Current Assignee: RIC INVESTMENTS LLC (Respironics Incorporated)
• Original Assignee: RIC INVESTMENTS LLC (Respironics Incorporated)
• Inventors: Russell, James T.
• Granted Patent: US 7,554,666 B2
• Time in Patent Office: Days
• US Class Current: 356/450
• CPC Class Codes: A61M 16/08 Bellows; Connecting tubes having means for taking samples G01N1/22; Water traps; Patient circuits
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• CPC Class Codes: A61M 16/0866 Passive resistors therefor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2016/102 Measuring a parameter of the content of the delivered gas
• CPC Class Codes: G01B 2290/25 Fabry-Perot in interferometer, e.g. etalon, cavity
• CPC Class Codes: G01B 9/02023 Indirect probing of object, e.g. via influence on cavity or fibre
• CPC Class Codes: G01F 1/38 the pressure or differential pressure being measured by means of a movable element, e.g. diaphragm, piston, Bourdon tube or flexible capsule
• CPC Class Codes: G01F 1/383 with electrical or electro-mechanical indication
• CPC Class Codes: G01F 1/40 Details of construction of the flow constriction devices
• CPC Class Codes: G01L 9/0077 for measuring reflected light

Abstract

An airway adapter that comprises a housing and a pressure transducer. The housing comprises a flow path having a first end and a second end, a first pressure port that communicates with the flow path, and a second pressure port that communicates with the flow path. The first pressure port is spaced apart from the second pressure port. The flow restriction is disposed in the flow path between the first and second pressure ports that creates a pressure differential therebetween. The pressure transducer generates a signal that reflects the differential pressure created by the flow restriction between the first and second pressure ports, wherein the pressure transducer comprises an optical interferometer.

Claims

1. An airway adapter comprising:

(a) a housing comprising;

(i) a flow path,

(ii) a first pressure port that communicates with the flow path, and

(iii) a second pressure port that communicates with the flow path, wherein the first pressure port is spaced apart from the second pressure port;

(b) a flow restriction disposed in the flow path between the first and second pressure ports and that creates a pressure differential therebetween; and

(c) a pressure transducer that generates a signal that reflects the differential pressure created by the flow restriction between the first and second pressure ports, wherein the pressure transducer comprises an optical interferometer.

2. The airway adaptor of claim 1, further comprising:

a detection chamber disposed within the flow path, the detection chamber having a pair of transmissive windows comprising a material at least partially transmissive for a selected wavelength, such that, during operation, a beam of radiation of the selected wavelength passes through the windows and traverses the detection chamber to be detected by a photodetector, the detected radiation being useable for measuring a constituent of a gas flowing through the detection chamber.

3. The airway adaptor of claim 2, wherein the flow restriction includes differences in cross sectional area between the detection chamber and one or more other portions of the flow path.

4. The airway adaptor of claim 1, further comprising a channel formed within the housing that runs from the first pressure port to the second pressure port, wherein at least a portion of the pressure transducer is disposed within the channel.

5. The airway adaptor of claim 4, wherein the pressure transducer further comprises a diaphragm disposed in the channel to substantially seal the first pressure port from the second pressure port such that the pressure differential between the first pressure port and the second pressure port causes a deformation of the diaphragm, and wherein the signal generated by the pressure transducer that reflects the pressure differential created by the flow restriction between the first and second pressure ports comprises a signal generated by the optical interferometer that reflects the deformation of the diaphragm.

6. The airway adaptor of claim 5, further comprising a transmissive window formed in a wall of the channel, wherein the optical interferometer comprises:

(i) a source that emits electromagnetic radiation through the transmissive window formed in the wall of the channel toward the diaphragm, and

(ii) a photodector that receives electromagnetic radiation from the diaphragm through the transmissive window formed in the wall of the channel, and wherein the signal generated by the optical interferometer that reflects the deformation of the diaphragm comprises a signal generated by the photodetector that reflects one or more characteristics of the electromagnetic radiation received by the photodetector.

7. The airway adaptor of claim 6, wherein one or more characteristics of the electromagnetic radiation comprise an intensity of the electromagnetic radiation and/or a phase of the electromagnetic radiation.

8. The airway adaptor of claim 1, wherein the first pressure port comprises a member constructed and arranged to reduce ingress of moisture from the flow path into the channel.

9. The airway adaptor of claim 5, wherein the diaphragm is disposed at the first pressure port or the second pressure port.

10. An airway adapter comprising:

(a) a housing comprising;

(i) a flow path,

(ii) a first pressure port that communicates with the flow path, and

(iii) a second pressure port that communicates with the flow path, wherein the first pressure port is spaced apart from the second pressure port;

(b) a pressure transducer that generates a signal that reflects a pressure differential created between the first pressure port and the second pressure port; and

(c) a channel formed within the housing that communicates the first pressure port with the second pressure port, wherein the pressure transducer comprises a diaphragm disposed within the housing and communicating with the channel, the channel being formed proximate to an outer surface of the flow path.

11. The airway adaptor of claim 10, wherein the channel is substantially parallel to the flow path.

12. The airway adaptor of claim 10, wherein the channel is directly adjacent to the outer surface of the flow path.

13. The airway adaptor of claim 10, further comprising a flow restriction disposed in the flow path between the first pressure port and the second pressure port to create the pressure differential.

14. An airway adaptor as in claim 10, further comprising a member constructed and arranged to reduce ingress of moisture from the passage into the channel, wherein the member is disposed proximate to the first pressure port.

15. An airway adaptor as in claim 10, wherein the channel is integrally molded as part of the housing.

16. An airway adaptor as in claim 10, wherein the diaphragm forms a portion of a boundary of the flow path.

17. A method of manufacturing an interferometer comprising:

coating a substrate with a first layer of a first material, the first layer being at least partially transmissive and at least partially reflective for electromagnetic radiation within a wavelength range;

coating the first layer with a layer of photoresist;

coating the layer of photoresist with a second layer of a second material, the second layer being substantially reflective for electromagnetic radiation with the wavelength range;

exposing the photoresist to patterned electromagnetic radiation, the patterned electromagnetic radiation having a wavelength within the wavelength range; and

wherein the photoresist exposed to electromagnetic radiation is developed to form one or more spacers; and

removing undeveloped photoresist from between the first layer and the second layer such that the spacers support the first layer and the second layer apart from one another to create a space between the first layer and the second layer.

18. The method of claim 17, further comprising coating the second layer of material with a diaphragm material.

19. The method of claim 17, further comprising cutting the substrate into a plurality of sensor elements, each sensor element comprising a portion of the substrate that was exposed to an exposure beam of electromagnetic radiation during the step of exposing the photoresist.

20. The method of claim 17, wherein the layer of photoresist has a thickness equal to nλ

/4+λ

/8, where n is an odd integer and λ

is the selected wavelength.

21. The method of claim 17, further comprising, prior to the step of coating the substrate with a first layer, processing the substrate so that it is substantially flat.

22. The method of claim 17, wherein the first material is aluminum and the first layer has an optical reflectivity between about 40% and about 60% for electromagnetic radiation with the selected wavelength.

23. The method of claim 17, wherein the second material comprises one of chromium or aluminum.

24. The method of claim 17, wherein the first material and the second material are the same material.