| JP2000258274 | PRESSURE SENSOR FOR PAPER SHEET COUNTER |
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| JP02293635 | OPTICAL FIBER SENSOR FOR MEASURING THREE PARAMETERS SYSTEM THEREOF |
SPELDRICH, Jamie W. (17 East Roosevelt Street, Freeport, IL, 61032, US)
CLAIMS
1. A pressure sensor mounted in a housing on a PC board, comprising: a housing; a PC board having a pressure sensor mounted thereon; and a pedestal positioned between said housing and said PC board, said pedestal having a first end mounted on said housing and a second end bonded to said pressure sensor, said pedestal having a central column forming said second end, said central column having a central opening for communication between said sensor and said housing and an opening on the outside of said central column isolating said pedestal from said PC board.
2. The device of claim 1, which further includes sealing means between said housing and said first end of said pedestal.
3. The device of claim 2, wherein said sealing means is an "o" ring seal.
4. The device of claim 1, wherein said central column is cylindrical and said opening on the outside of said column is an annular space.
5. The device of claim 4, wherein said device further includes a pressure sensor cover mounted over said sensor and attached thereto by clamp means.
6. The device of claim 1, which further includes a pressure sensor support mounted between said sensor and said central column, wherein said second end is bonded to said pressure sensor using an adhesive.
7. A pressure sensor mounted in a housing on a PC board, comprising: housing means for mounting a PC board; a PC board having a pressure sensor mounted thereon; and pedestal means for mounting said sensor and positioned between said housing means and said PC board, said pedestal means having a first end mounted on said housing and a second end bonded to said pressure sensor, said pedestal means having a central column means for isolating said pedestal means from said PC board, said central column means forming said second end, said central column means having a central opening for communication between said sensor and said housing means and an opening on the outside of said central column means isolating said pedestal means from said PC board.
9. In a pressure sensor mounted in a housing on a PC board, having a housing and a PC board having a pressure sensor mounted thereon, the improvement comprising: a pedestal positioned between said housing and said PC board, said pedestal having a first end mounted on said housing and a second end bonded to said pressure sensor, said pedestal having a central column forming said second end, said central column having a central opening for communication between said sensor and said housing and an opening on the outside of said central column isolating said pedestal from said PC board.
10. The device of claim 9, which further includes sealing means between said housing and said first end of said pedestal and wherein said sealing means is an "o" ring seal. |
PRESSURE SENSOR STRESS ISOLATION PEDESTAL
FIELD OF THE INVENTION
The present invention relates to pressure sensors. More particularly, the present invention relates to MEMS types pressure sensors that are sensitive to mechanical and thermal stress.
BACKGROUND OF THE INVENTION
There are many different elements that are attached to PC boards and other electronic devices. Often these devices function as designed and offer no problems. Other times, however, mechanical and/or thermal stress has an adverse affect on the sensor and the output is no longer reliable. For example, MEMS type pressure sensors are quite sensitive to mechanical and thermal stress. This stress induces a shift in the null output.
Accordingly, one advantage of the present invention is to provide a device which minimizes or eliminates mechanical and/or thermal stress on sensors, particularly on sensors mounted on PC boards.
Another advantage of the present invention is to provide a means for mounting the sensor that isolates the sensor from the PC board to reduce or eliminate stress from the PC board to the sensor. Other advantages will appear hereinafter.
SUMMARY OF THE INVENTION
It has now been discovered that the above and other advantages of the present invention may be obtained in the following manner. In its simplest form, the present invention comprises an improvement in the way a pressure sensor is mounted in a housing.
The invention includes a pedestal positioned in the housing to isolate the pressure sensor from mechanical and thermal shock. The pedestal includes a central column wherein the central column has a central opening to permit communication between the sensor and the pressure source. The pressure sensor is attached to the first end of the central column with an adhesive bond. An opening on the outside of said central column isolated the pedestal from the circuit board and housing structure and prevents transmission of mechanical and thermal stress.
The central column is preferably square in shape. The central opening is a cylinder and the opening on the outside of the column is square recess.
The device preferably may include a pressure sensor cover mounted over the sensor and attached thereto by an adhesive.
The device may also be incorporated into a housing with a seal placed between the housing and the first end of the pedestal. A preferred sealing means is an "o" ring seal. An alternative means of sealing is adhesive.
The device may also a pressure sensor support mounted between the sensor and the central column, wherein the second end is bonded to the pressure sensor using an adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the invention, reference is hereby made to the drawings, wherein like numbers refer to like elements, and in which: FIGURE 1 is a sectioned side elevational view of one embodiment of the present invention; and
FIGURE 2 is an alternative embodiment with o-ring seal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in the drawings, the device of this invention, 10 generally, illustrate a housing 23 which mounts the sensor 13 on sensor support 15 using adhesive 29 placed on the central column 21 of housing 23. As can be seen, the central column 21 of housing 23 is square, having a center hole for communication between the sensor and pressure source, The central portion of housing 23 also have recesses 31 which isolate stress from housing 23 and PC board 11. Recess 31 is a square annular space around the square central column 21.
Figure 2 shows an alternative embodiment in which elements from Figure 1 are incorporated into a second level structure. A circuit board 11 includes a pressure sensor 13 as part of the function of the circuit board. The sensor 13 is placed on a sensor support 15, of conventional design. A cover 17 is attached over the sensor by adhesively bonding cover 17 to the device in the direction of arrow 21. Cover 17 also has a vent area 19, as is also conventional in design.
The present invention makes use of a pedestal 23 to isolate the sensor from outside stresses such as from the PC board or when the whole device is moved. Pedestal 23 is mounted with seal 25 on housing 27. A preferred seal is an "O" ring seal. While particular embodiments of the present invention have been illustrated and described, it is not intended to limit the invention, except as defined by the following claims.
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