The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 01, 1994
Filed:
Jun. 19, 1992
Shizuki Sakurai, Nagoya, JP;
Tomio Nagata, Chiryu, JP;
Shiro Kuwahara, Anjo, JP;
Osamu Tabata, Aichi, JP;
Susumu Sugiyama, Nagoya, JP;
Toyoda Koki Kabushiki Kaisha, Kariya, JP;
Kabushiki Kaisha Toyota Chuo Kenkyusho, Aichi, JP;
Abstract
A digital capacitive sensing device comprises: a reference capacitor having a reference capacitance unaffected by a force to be measured; a reference pulse signal generating circuit which generates a reference pulse signal of a frequency corresponding to the reference capacitance; a sensing capacitor having capacitance variable according to the magnitude of the force; a measuring pulse signal generating circuit having a construction similar to that of the reference pulse signal generating circuit and capable of generating a measuring pulse signal of a frequency corresponding to the capacitance of the sensing capacitor; and a differential arithmetic circuit which adds the number of pulses of the reference pulse signal in a predetermined time interval to a set value and subtracts the number of pulses of the measuring pulse signal in a predetermined time interval from the set value. The reference pulse signal generating circuit is capable of compensating a zero point temperature characteristic of a detection value, and the measuring pulse signal generating circuit is capable of compensating a detection sensitivity temperature characteristic.