Small form-factor pressure sensor passages

• US 9,498,161 B1
• Filed: 10/16/2015
• Issued: 11/22/2016
• Est. Priority Date: 10/16/2015
• Status: Active Grant

• Current Assignee: Fitbit, Inc. (Alphabet Inc.)
• Original Assignee: Fitbit, Inc. (Alphabet Inc.)
• Inventors: Martino, Samuel Paul, Sunden, Lindsey Michelle, Hong, Jung Ook, Yuen, Shelten Gee Jao, Francisco, Michael Joseph
• Primary Examiner(s): ALLEN, ANDRE J
• Application Number:
  US14/885,817
• Time in Patent Office: 403 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0257 using atmospheric pressure
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: G01C 5/06 by using barometric means

Abstract

Passages for communicating ambient air to a pressure sensor within a housing are provided; such passages may have particular cross-sectional characteristics that result in higher-quality pressure data having less noise than may be obtained used passages having other cross-sectional characteristics.

Claims

1. A wearable biometric monitoring device, comprising:

a pressure sensor;

a housing that includes a first vent; and

a first passage in the housing, wherein;

the first passage provides a first path from the first vent to the pressure sensor,

the first passage has a first cross-section in a plane perpendicular to the first path at at least a first point along the first path,

the first cross-section has a first dimension in a first direction and a second dimension in a second direction orthogonal to the first direction, and

the first dimension is at least one and a half times as large as the second dimension.

2. The wearable biometric monitoring device of claim 1, wherein the first dimension is 2 mm or more.

3. The wearable biometric monitoring device of claim 1, wherein the first direction is tangent to the average exterior surface of the housing at a location closest to the first point.

4. The wearable biometric monitoring device of claim 1, wherein the first dimension is between 2 mm and 4 mm and the second dimension is between 0.3 mm and 1 mm.

5. The wearable biometric monitoring device of claim 1, wherein the first path has a path length of at least 2 mm.

6. The wearable biometric monitoring device of claim 1, wherein the first dimension is greater than 1 mm.

7. The wearable biometric monitoring device of claim 1, wherein the first passage allows air external to the wearable biometric monitoring device to travel from the first vent to the pressure sensor.

8. The wearable biometric monitoring device of claim 1, wherein:

a portion of an exterior surface of the housing forms a recess, and

the first vent is located in the recess.

9. The wearable biometric monitoring device of claim 8, wherein:

the recess is located in the exterior surface of the housing such that the exterior surface of the housing immediately surrounding the recess is adjacent to, and faces towards, a person'"'"'s skin when the wearable biometric monitoring device is worn,

the housing further includes;

a second passage, and

a second vent that is located on the exterior surface of the housing in a location that is not adjacent to, and does not face towards, the person'"'"'s skin when the wearable biometric monitoring device is worn;

the second passage provides a second path from the recess to the second vent,

the second passage allows air pressure external to the wearable biometric monitoring device to travel from the second vent to the recess,

the second passage has a second cross-section in a plane perpendicular to the second path at at least a second point along the second path,

the second cross-section has a third dimension in a third direction and a fourth dimension in a fourth direction orthogonal to the third direction, and

the third dimension is at least one and a half times as large as the fourth dimension.

10. The wearable biometric monitoring device of claim 9, wherein the recess is configured to allow pressure to travel between the first passage to the second passage even when the wearable biometric monitoring device is worn by the person and the exterior surface of the housing immediately surrounding the recess is thereby covered by the person'"'"'s skin.

11. The wearable biometric monitoring device of claim 9, wherein:

the recess includes a protrusion within the recess,

a gap exists between the protrusion and the sidewalls of the recess,

the gap has a gap depth defined by either a height of the protrusion or a depth of the recess and a gap width defined by an offset distance between the sidewalls and the protrusion, and

the gap depth is at least one and a half times as large as the gap width.

12. The wearable biometric monitoring device of claim 9, wherein the second path is straight.

13. The wearable biometric monitoring device of claim 9, wherein the second path follows a 2-dimensional curve in a plane normal to the first direction.

14. The wearable biometric monitoring device of claim 9, wherein:

the housing includes a housing body and a cover piece,

the second vent is located on the cover piece, and

the first passage and the second passage are, at least in part, defined by surfaces of the housing body and the cover piece when the cover piece is assembled to the housing body.

15. The wearable biometric monitoring device of claim 14, wherein the first path follows an interior surface of the cover piece.

16. The wearable biometric monitoring device of claim 1, wherein the first dimension is at least one and a half times the second dimension for the first cross-section at first points located along at least 90% of the first path.

17. The wearable biometric monitoring device of claim 1, wherein the first cross-section varies in shape, size, or dimension along at least a portion of the first path.

18. The wearable biometric monitoring device of claim 1, wherein the first path is straight.

19. The wearable biometric monitoring device of claim 1, wherein the first path follows a 2-dimensional curve in a plane normal to the first direction.

20. The wearable biometric monitoring device of claim 1, wherein the first cross-section is substantially rectangular.

21. The wearable biometric monitoring device of claim 1, wherein the first cross-section is rectangular with internal fillets.

22. The wearable biometric monitoring device of claim 1, wherein:

the housing includes a second vent,

the first vent is located at a first location on an outer surface of the housing,

the second vent is located at a second location on the outer surface of the housing,

the first passage provides a first path from the second vent to the pressure sensor,

the first passage allows air external to the wearable biometric monitoring device to travel from the first vent to the pressure sensor, and

the first passage allows air external to the wearable biometric monitoring device to travel from the second vent to the pressure sensor.

23. The wearable biometric monitoring device of claim 22, wherein the first dimension is at least three times as large as the second dimension.

24. The wearable biometric monitoring device of claim 22, wherein:

the housing includes a housing body and a cover piece,

the first passage is, at least in part, defined by surfaces of the housing body and the cover piece when the cover piece is assembled to the housing body,

the first vent extends through the cover piece,

the second vent extends through the cover piece or the housing body, and

the first location is located such that the first vent is not facing into a person'"'"'s skin when the wearable biometric monitoring device is worn.

25. A wearable biometric monitoring device, comprising:

a pressure sensor; and

a housing, the housing including;

a pressure sensor plenum volume in fluidic communication with the pressure sensor,

a first passage, with a first vent on an exterior surface of the housing, that allows air pressure external to the wearable biometric monitoring device to travel from the first vent to the pressure sensor,

a second passage, with a second vent on the exterior surface of the housing, that allows air pressure external to the wearable biometric monitoring device to travel from the second vent to the pressure sensor,

a third passage, with a third vent on the exterior surface of the housing, that allows air pressure external to the wearable biometric monitoring device to travel from the third vent to the pressure sensor, and

a fourth passage, with a fourth vent on the exterior surface of the housing, that allows air pressure external to the wearable biometric monitoring device to travel from the fourth vent to the pressure sensor, wherein;

the first passage extends away from the pressure sensor plenum volume in a first direction,

the second passage extends away from the pressure sensor plenum volume in a second direction,

the third passage extends away from the pressure sensor plenum volume in a third direction,

the fourth passage extends away from the pressure sensor plenum volume in a fourth direction,

the first passage has a first dimension in a third direction and a corresponding second dimension in a fourth direction orthogonal to the third direction,

the second passage has a third dimension in a fifth direction and a corresponding fourth dimension in a sixth direction orthogonal to the fifth direction,

the third passage has a fifth dimension in a seventh direction and a corresponding sixth dimension in a eighth direction orthogonal to the seventh direction,

the fourth passage has a seventh dimension in a ninth direction and a corresponding eighth dimension in a tenth direction orthogonal to the ninth direction,

two or more of the first dimension, the third dimension, the fifth dimension, and the seventh dimension are within ±

10% of each other, and

two or more of the second dimension, the fourth dimension, the sixth dimension, and the eighth dimension are within ±

10% of each other.

26. The wearable biometric monitoring device of claim 25, wherein the first passage, the second passage, the third passage, and the fourth passage all have substantially circular cross-sections with cross-sectional areas of less than 1 square millimeter.

27. The wearable biometric monitoring device of claim 25, wherein:

the first direction and the second direction are parallel paths within the housing, and

the third direction and the fourth direction are parallel paths within the housing.

28. The wearable biometric monitoring device of claim 25, wherein one or more of the first passage, the second passage, the third passage, and the fourth passage have a semicircular cross-section.

29. The wearable biometric monitoring device of claim 25, wherein more than one of the first direction, the second direction, the third direction, and the fourth direction are parallel with one another.

30. The wearable biometric monitoring device of claim 25, wherein:

three or more of the first dimension, the third dimension, the fifth dimension, and the seventh dimension are within ±

10% of each other; and

three or more of the second dimension, the fourth dimension, the sixth dimension, and the eighth dimension are within ±

10% of each other.