Abstract: Several force sensor assemblies are disposed within a vehicle seat to determine seat loading and assist in safety device activation. Each force sensor assembly has a sealed body filled with a liquid or a gel. A pressure transducer, together with a supporting integrated circuit, is positioned to respond to the pressure of the liquid or gel. Loads are applied to the pressure transducer through the gel by a piston riding within the body. Compressive loads are thereby transformed into a pressure on the sensor and its support electronics, resulting in a low cost, accurate, and durable sensor. The sensor functions well for relatively low loads of less than a few hundred pounds.

Abstract: A capacitive detector for absolute pressure, which comprises a base and a stationary capacitor plate (7) attached onto the base (3). An aneroid capsule (4) is arranged in connection with the base (3) and provided with a mobile capacitor plate area (5, 6) directed towards the base (3) and changing its distance from the stationary capacitor plate (7) by the effect of pressure. A silicon plate (2) is attached onto the base and has membrane-like middle portion (5, 6) acting as a mobile capacitor plate. A plate structure (1) is attached hermetically onto the silicon plate (2) such that the space of the aneroid capsule (4) is located between the plate structure (1) and the silicon plate (2).

Abstract: A capacitive pressure detector, comprising a plate-shaped base (13), a stationary capacitor plate (14) disposed on the base (13), an aneroid capsule (6) arranged in connection with the base (13) and proviced with an area (8) with a mobile capacitor plate facing the stationary capacitor plate (14) and changing its distance from the stationary capacitor disc (14) by the effect of pressure. On the plate-shaped base (13), a silicon plate (5) is disposed, into which a membrane-like middle portion (8) functioning as the mobile capacitor plate has been worked. On the silicon plate (5), a preferably plate-shaped cover structure (12) is hermetically disposed so that a basin space (6) of the aneroid capsule is formed between the cover structure (12) and said middle portion (8).

Abstract: A capacitive pressure detector, which comprises a support plate (5, 6; 19), a stationary capacitor plate (4; 7) disposed on the support plate, (5, 6; 19), and a silicon plate (2; 13) disposed on the support plate (5, 6; 19) so that it surrounds the stationary capacitor plate (4; 7), the middle portion of the silicon plate having been made thinner so that it forms membrane-like structure (3; 16) acting as a mobile capacitor plate. The support plate consists of a silicon layer (6; 21) and of a glass layer (5; 20) attached onto said silicon layer and placed against the silicon plate (2; 13), said glass layer being essentially thinner than the silicon layer. Hence, in the combination plate (5, 6; 20, 21) in this way obtained, owing to the elasticity coefficients and thermal expansion coefficients of the different layers (5 and 6; 20 and 21), the difference in thermal expansion between the combination plate (5, 6; 20, 21) and the silicon membrane (3; 16) is essentially reduced.

Abstract: The present publication describes a capacitive humidity sensor and a method for the manufacture of same. The sensor comprises a substrate (1), first (5) and second bottom electrodes (4), which have been fitted close to each other on the substrate (1), an active layer (7), which fills the area between the first (5) and the second bottom electrodes (4) on the substrate (1) and extends to above the top face of the second electrode (4). According to the invention, the sensor further consists of structures (6) connected to the top face of the first electrode (5), made of a conductive material, and being beam-shaped with an upwardly widening section and being placed side by side, the said structures (6) limiting portions (7) of the active layer between themselves from two sides, and a narrow slot (26) being provided between the top faces of the said structures. Owing to its construction, the sensor is not sensitive to touching.