US4451780A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-contact type microdisplacement meter
Assignee: Individual
•
Filing: 1981-09-21
•
Granted: 1984-05-29
•
Expires: 2001-09-21
Abstract
Abstract In a non-contact type microdisplacement meter, two electrodes different in area are confronted with an object under measurement to form two electrostatic capacitances between the object and the electrodes, and the capacitances are coupled to two oscillator circuits, so that a displacement signal is provided as the frequency difference between the oscillator circuit, thereby to measure the very small displacement of the object.
Inventors
- 👤 Hiroomi Ogasawara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:27
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/12; G01B7/02; G01B7/13; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/24; G01D5/241; G01D5/2417
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
169 words
A non-contact type microdisplacement indicating circuit for determining the displacement of an object comprising: a main electrode having an area A M ; an auxiliary electrode having an area A S ; means positioning said main electrode to confront the object at a distance d M , to form therewith a first capacitor having a capacitance C M , which is a function of A M and d M , and positioning said auxiliary electrode to confront the object at a distance d S , to form therewith a second capacitor having a capacitance C S , which is a function of A S and d S ; a first oscillator circuit having said first capacitor incorporated therein as a frequency varying component; a second oscillator circuit having said first capacitor incorporated therein as a frequency varying component; and a mixer coupled to said first and second oscillator circuits for providing a frequency difference signal determined by the difference in the frequencies of said first and second oscillator circuits.
Claim 2
Dependent Claim
169 words
A non-contact type microdisplacement indicating circuit for determining the displacement of an object comprising: a main electrode having an area A M ; an auxiliary electrode having an area A S ; means positioning said main electrode to confront the object at a distance d M , to form therewith a first capacitor having a capacitance C M , which is a function of A M and d M , and positioning said auxiliary electrode to confront the object at a distance d S , to form therewith a second capacitor having a capacitance C S , which is a function of A S and d S ; a first oscillator circuit having said first capacitor incorporated therein as a frequency varying component; a second oscillator circuit having said first capacitor incorporated therein as a frequency varying component; and a mixer coupled to said first and second oscillator circuits for providing a frequency difference signal determined by the difference in the frequencies of said first and second oscillator circuits.
Claim 3
Dependent Claim
22 words
A circuit as claimed in claim 1 in which said positioning means positions said electrodes so that d M =d S .
Claim 4
Dependent Claim
22 words
A circuit as claimed in claim 1 in which said positioning means positions said electrodes so that d M ≠d S .
Claim 5
Dependent Claim
17 words
A circuit as claimed in claim 3 in which d S is greater than d M .
Claim 6
Dependent Claim
14 words
A circuit as claimed in claim 1 in which A M ≠A S .
Claim 7
Dependent Claim
17 words
A circuit as claimed in claim 5 in which A M is greater than A S .
Claim 8
Dependent Claim
23 words
A circuit as claimed in claim 1 further comprising radio transmission means and radio reception means coupling said oscillator circuits to said mixer.
Claim 9
Dependent Claim
26 words
A circuit as claimed in claim 1 further comprising radio transmission means coupled to said mixer for transmitting the frequency difference signal to a radio receiver.
Claim 10
Dependent Claim
19 words
A circuit as claimed in claim 1 in which each of said oscillator circuits comprises a crystal oscillator circuit.
References Cited (Backward Citations)
US3046479A
Cited
US3221256A
Cited
US3764899A
Cited
US4025846A
Cited
US4227182A
Cited
US4112355A
Cited
US4238782A
Cited
US4297634A
Cited
US4347478A
Cited
US4301401A
Cited
US4300093A
Cited
JPS56141512A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-29 | 1987-11-28 | 1988-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-29 | 1991-11-28 | 1992-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-29 | 1995-11-28 | 1996-05-29 | $7700.00 | Window Closed / Lapsed |