Claims
- 1. A silicon micromechanical weight sensor comprising:a first conducting electrode; a second conducting electrode displaced at a distance from said first conducting electrode; a plurality of suspension means elastically suspending said first conducting electrode; a pan surface for receiving an object to be weighed and applying weight to said first conducting electrode; means for maintaining a constant distance between said first conducting electrode and said second conducting electrode by applying an electrical signal thereto and generating a weight signal based on the applied signal; at least one of said first conducting electrode and said second conducting electrode being divided into a plurality of partial areas so that said electrical signal for maintaining a constant distance is applied to each partial area separately in order to maintain said first and second conducting electrodes in a parallel arrangement.
- 2. The silicon micromechanical weight sensor according to claim 1, wherein said means for maintaining a constant distance includes means for detecting the distance between said first and second conducting electrodes.
- 3. The silicon micromechanical weight sensor according to claim 1, wherein said first conducting electrode and said second conducting electrode are essentially planar.
- 4. The silicon micromechanical weight sensor according to claim 1, wherein said means for maintaining said constant distance includes a tuned AC bridge with an AC signal source feeding the bridge, a differential circuit detecting the balance of the bridge, a first branch being formed from stable components, another branch including capacitive components, an output from the differential circuit being applied to a summing point to impose a voltage between the electrodes and generating a feedback voltage indicative of the measured weight.
- 5. The silicon miromechanical weight sensor according to claim 4, wherein the capacitive components include fixed capacitive components and a capacitor formed by said first conducting electrode and said second conducting electrode.
- 6. The silicon micromechanical weight sensor according to claim 1, wherein said second conducting electrode is fixed.
- 7. The silicon micromechanical weight sensor according to claim 1, wherein said plurality of partial areas form radial sectors.
Priority Claims (2)
Number |
Date |
Country |
Kind |
981458 |
Jun 1998 |
FI |
|
982832 |
Dec 1998 |
FI |
|
Parent Case Info
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/FI99/00538 which has an International filing date of Jun. 18, 1999, which designated the United States of America.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/FI99/00538 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO99/67605 |
12/29/1999 |
WO |
A |
US Referenced Citations (9)
Foreign Referenced Citations (1)
Number |
Date |
Country |
3426165 |
Apr 1985 |
DE |