Impedance detector, in particular for radiosonde operation and process for manufacture of an impedance detector

• US 5,553,495 A
• Filed: 09/16/1994
• Issued: 09/10/1996
• Est. Priority Date: 09/29/1993
• Status: Expired due to Term

• Current Assignee: Vaisala OY
• Original Assignee: Vaisala OY
• Inventors: Paukkunen, Ari, Ponkala, Jorma
• Primary Examiner(s): Noland, Thomas P.
• Assistant Examiner(s): WIGGINS, JOHN DAVID
• Application Number:
  US08/307,057
• Time in Patent Office: 725 Days
• Field of Search: 73/335.03, 73/29.05, 73/29.02, 73/335.04, 73/29.01, 29/825, 29/25.42, 427/79, 427/80, 324/664, 324/689
• US Class Current: 73/335.03
• CPC Class Codes: G01D 5/2405 by varying dielectric
• CPC Class Codes: G01K 7/343 the dielectric constant of which is temperature dependant
• CPC Class Codes: G01N 27/225 by using hygroscopic materials
• CPC Class Codes: H01G 13/00 Apparatus specially adapted for manufacturing capacitors; Processes specially adapted for manufacturing capacitors not provided for in groups H01G4/00 - H01G11/00
• CPC Class Codes: Y10T 29/435 Solid dielectric type
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

An impedance detector, in particular for radiosonde operation. The detector comprises a substrate (10 . . . 10E) made of an insulating material, onto which substrate the electrode and contact patterns (11, 11a, 13) necessary for the formation and connecting of the detector impedance have been applied. Between the detector impedance electrodes (11,13), there is an active film (12), whose impedance values are a function of the physical quantity measured by means of the detector. The substrate of the detector is an oblong core filament (10;10B;10C;10D;10E) of an insulating material, onto and around which core filament both electrodes (11,13) and such active insulating film (12) have been applied. Also, a novel process is described for the manufacture of such impedance detector.

Claims

1. Impedance detector, in particular for radiosonde operation, which detector comprises a substrate (10 . . . 10E) made of an insulating material, onto which substrate the electrode and contact patterns (11, 11a, 13) necessary for the formation and connecting of the detector impedance electrodes (11, 13) have been applied, and in which detector between the detector impedance electrodes (11, 13) there is an active film (12) whose impedance values are a function of the physical quantity measured by means of the detector, characterized in that:

the substrate of the detector is an oblong core filament (10;

10B;

10C;

10D;

10E) of an insulating material, onto and around which core filament said electrodes (11,13) and said active insulating film (12) have been applied;

the core filament (10C) of the detector is made of dielectric ceramic glass, which operates as the dielectric for the measurement of the temperature of the detector;

in connection with said core (10B), contact patterns or equivalent are provided, between which the temperature-dependent capacitance can be measured, and;

the outer layer (16) of the core filament (10C) is selected from the group consisting of a glass layer and another insulating layer (FIG. 4C).

2. Process for the manufacture of an impedance detector, characterized in that the process comprises a combination of the following steps (a), (b), (c), and (d) carried out in the given sequence:

(a) onto the continuous core filament (10;

10B;

10C;

10D;

10E) of insulating material, conductive bottom electrodes (11) are vapour-deposited at a certain mutual axial distance (L₀) from one another;

(b) the continuous core filament (10) obtained in the step (a) is coated with a material active in the measurement of impedance;

(c) the continuous core filament (10) obtained in the step (b) is coated with conductive surface electrodes (13), which are placed at least partly facing the gaps (L₀) between said bottom electrodes (11) and at least partly facing the bottom electrodes (11), and

(d) the continuous detector filament (100) obtained from the step (c) is cut off into pieces to make the impedance detectors.

3. Process as claimed in claim 2, characterized in that said steps (a) and (b) are carried out by reeling the core filament (10) from a starting reel (28a,30a) onto an arrival reel (28b,30b).

4. Process as claimed in claim 2, characterized in that the continuous detector filament (10) obtained from the step (c) is cut off into detectors at the bottom electrodes (11), preferably substantially at their middle, and that contact areas (11a) are uncovered in a peeling or etching process at the ends of said bottom electrodes (11), and electric connectors (19) of the detector are connected to said contact areas, preferably by means of an electrically conductive adhesive.

5. Process as claimed in claim 2, characterized in that the continuous detector filament (10) is cut off into detectors at the gaps between the bottom electrodes (11) and the surface electrodes (13) free from said electrodes (11, 13).

6. Process of manufacture as claimed in claim 2 characterized in that the making of the bottom electrodes (11) in accordance with the step (a) takes place so that the core filament (10) is reeled from a starting reel (28a) onto an arrival reel (28b) stepwise through a mask part (21).

7. Process of manufacture as claimed in claim 2, characterized in that the coating in accordance with the step (b) of the core filament (10) that is provided with bottom electrodes (11) takes place so that the core filament (10) is passed from a starting reel (30a) onto an arrival reel (30b) through a basin (31) that contains a coating-agent solution (PL) or melt or through an equivalent crucible for drawing through, preferably at an invariable speed, whereupon the coated core filament (10) is, if necessary, passed through a drying step (33) placed before the arrival reel (30b) (FIG. 8).

8. Process of manufacture as claimed in claim 2, characterized in that the continuous core filament (10) that is used in the step (a) is manufactured by in its interior and/or on said filament placing a resistor wire (14;

14A, 14B;

14C), and that the core filament that has been manufactured in the steps mentioned above is coated with a layer of insulating material (16).

9. Process of manufacture as claimed in claim 2, characterized in that, in the process, the glass core (10b) is made of dielectric glass, which is fitted as the dielectric of the capacitor used in capacitive measurement of temperature in the detector.