JP4161460B2

JP4161460B2 - Bioimpedance measurement device

Info

Publication number: JP4161460B2
Application number: JP08330899A
Authority: JP
Inventors: 弘文乾; 洋一黒木; 加寿子粟屋; 恭宏河本
Original assignee: Matsushita Electric Works Ltd
Current assignee: Panasonic Electric Works Co Ltd
Priority date: 1999-03-26
Filing date: 1999-03-26
Publication date: 2008-10-08
Anticipated expiration: 2019-03-26
Also published as: JP2000271101A

Description

【０００１】
【発明の属する技術分野】
本発明は、生体に高周波電流を流して生体のインピ−ダンスを測定し、生体のインピ−ダンスと、身体や体重等の身体条件から体内の体脂肪量を算出する体脂肪量計等の生体のインピ−ダンスを測定する装置に関するものである。
【０００２】
【従来の技術】
一般に体内の脂肪量を測定する方法としては、両手間など身体の末端間のインピ−ダンスを４端子法で生体インピ−ダンスを測定し、身長や体重など身体の情報から体内脂肪量を算出する方法が提案されている。
【０００３】
図８は、従来の生体インピ−ダンス測定装置の構成を示すブロック図である。生体インピ−ダンスの測定は、５０ｋＨｚの正弦波を発信器１から発生させ、この正弦波の電圧を電圧−電流変換手段２によって定電流化する。この定電流を生体に接触する電極３ａ、３ｂ間から生体に電流を流す。そして、前記電極３ａ、３ｂ間の電圧を差動増幅器４で取りだし、フィルタ回路などで波形を整形して整流器５で直流変換した後，ＡＤ変換器６でアナログ値をＡＤ変換してデジタル数値としてマイクロコンピュ−タからなる演算部７に伝達される。この演算部７は電圧信号から生体インピ−ダンスを算出している。
【０００４】
生体インピ−ダンスＺは生体電流Ｉと電極電圧Ｖとの関係において、Ｚ＝Ｖ／Ｉが成り立ち、電流Ｉが一定の時に電極電圧Ｖを検出することにより、生体インピ−ダンスＺを求めることができる。前記生体インピ−ダンスＺと身長や体重等の身体情報から体内の脂肪量を算出している。
【０００５】
【発明が解決しようとする課題】
前記従来の構成の生体インピ−ダンス測定装置は、定電流源が温度等の環境により変化した場合、この定電流の変化が生体インピ−ダンスの測定誤差の要因となっている。前記定電流源を定常値にするために、外部環境変動の低減や定電流源の精度向上等に多大な労力を要するものであった。
【０００６】
本発明は前記従来の課題を解決するもので、測定時の生体電流を検出して温度等の環境に影響されない精度の高い測定ができる生体インピ−ダンス測定装置を提供するものである。
【０００７】
【課題を解決するための手段】
本発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段を備えたものである。
【０００８】
上記手段において、電流検出抵抗で生体に流れる電流を検出して電流値を求めるので、温度等の外部環境に影響されない精度の高い測定をすることができる。
【０００９】
【発明の実施の形態】
本発明の請求項１に記載の発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、抵抗電圧検出手段と生体電圧検出手段の信号を差動増幅する差動増幅手段と、電極間を短絡するスイッチを備えたものである。
【００１０】
上記形態において、高周波電圧発生手段の電圧を電圧−電流変換手段で定電流化する。この定電流が電流検出抵抗と電極を介して生体に流れ、この電流によって発生した電流検出抵抗の電圧と電極間の電圧から演算手段は生体インピ−ダンスを算出する。従って、生体インピ−ダンスを算出するのに、常に電流検出抵抗の抵抗から生体に流れる電流を検出して行っているので、生体インピ−ダンス測定の精度を高められる。また、スイッチを閉じている場合は定電流が流れることにより発生した電流検出抵抗だけの電圧Ｖｏ１と、スイッチを開いている場合は定電流が電流検出抵抗と電極を介して生体に流れることにより発生した電圧Ｖｏ２との差を差動増幅器で検出し、この検出信号から演算手段は生体インピ−ダンスを演算する。従って、生体インピ−ダンスを演算するのに、常に測定時の電流Ｉ、前記電圧Ｖｏ１、電圧Ｖｏ２から生体に流れる電流を検出して行っているので、生体インピ−ダンス測定の精度を高められる。
【００１１】
また、請求項２に記載した発明は、請求項１記載において電流検出抵抗を短絡するスイッチを備えたものである。
【００１２】
上記形態において、スイッチを閉じている場合は定電流が電極を介して流れることにより発生した生体の電極間の電圧Ｖｏ１と、スイッチを開いている場合は電流検出抵抗と電極を介して生体に定電流が流れることにより、発生した電圧Ｖｏ２との差を差動増幅器で検出し、この検出信号から演算手段は生体インピ−ダンスを演算する。従って、生体インピ−ダンスを演算するのに、常に測定時の電流Ｉ、前記電圧Ｖｏ１、電圧Ｖｏ２から生体に流れる電流を検出して行っているので、生体インピ−ダンス測定の精度を高められる。
【００１３】
また、請求項３に記載した発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、電流検出抵抗と電極間との電圧を検出する電圧検出手段と、電流検出抵抗を短絡するスイッチを備えたものである。
【００１４】
上記形態において、スイッチを閉じている場合は、定電流が電極を介して生体に流れることによって発生した生体の電極間の電圧Ｖｏ１と、スイッチを開いている場合は定電流が電流検出抵抗と電極を介して生体に流れることによって発生した電圧の和の電圧Ｖｏ１とから演算手段は生体インピ−ダンスを演算する。従って、生体インピ−ダンスを演算するのに、常に測定時の電流Ｉ、前記電圧Ｖｏ１、電圧Ｖｏ２から生体に流れる電流を検出して行っているので、生体インピ−ダンス測定の精度を高められる。
【００１５】
また、請求項４に記載の発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、電流検出抵抗と電極間との電圧を検出する電圧検出手段と、電極間を短絡するスイッチを備えたものである。
【００１６】
上記形態において、スイッチを閉じている場合は定電流が流れることにより発生した電流検出抵抗だけの電圧Ｖｏ１と、スイッチが開いている場合は定電流が流れることによって発生した電流検出抵抗と生体の電極間との電圧の和の電圧Ｖｏ２から演算手段は生体インピ−ダンスを演算する。従って、生体インピ−ダンスを演算するのに、常に測定時の電流Ｉ、前記電圧Ｖｏ１、電圧Ｖｏ２から生体に流れる電流を検出して行っているので、生体インピ−ダンス測定の精度を高められる。
【００１７】
また、請求項５に記載した発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、抵抗値が電流検出抵抗と異なる抵抗と、この抵抗を前記電流検出抵抗に並列に接続するスイッチを備えたものである。
【００１８】
上記形態において、スイッチを閉じている場合は、定電流が電流検出抵抗、抵抗と電極間に流れることによって発生した電流検出抵抗と抵抗の並列回路の電圧Ｖｏ２と、スイッチを開いている場合は定電流が電流検出抵抗だけの電圧Ｖｏ１の差電圧と、電極を介して定電流が流れることより発生した生体の電極間の電圧から演算手段は生体インピ−ダンスを演算する。従って、生体インピ−ダンスを演算するのに、常に測定時の電流Ｉ、前記電圧Ｖｏ１、電圧Ｖｏ２から生体に流れる電流を検出して行っているので、生体インピ−ダンス測定の精度を高められる。
【００１９】
また、請求項６に記載した発明は、請求項１〜請求項５のいずれか１項に記載の生体電圧検出手段の信号により電極が生体に接触したことを検知する電極接触検知手段を備えたものである。
【００２０】
上記形態において、電極接触検知手段は生体電圧検出手段から信号を得て生体への電極の接触度を検知する。従って、測定回数を繰り返すことにより生体インピ−ダンス測定の精度を高められる。
【００２１】
【実施例】
以下本発明生体インピ−ダンス測定装置につき、図１〜図７を参照して説明する。
【００２２】
（参考例１）
図１は、生体インピ−ダンス測定装置の参考例１の発明を示すブロック図である。この生体インピ−ダンス測定装置は、５０ｋＨｚの正弦波を発生させる高周波電圧発生手段１０と、この高周波電圧発生手段１０の電圧を電流に変換する電圧−電流変換手段１１と、生体に接触する電極１２ａ，１２ｂと、この電極１２ａ，１２ｂに流れる電流を検出する電流検出抵抗１３と、この電流検出抵抗１３の電圧を検出する抵抗電圧検出手段１４と、前記電極１２ａ，１２ｂ間の生体の電圧を検出する生体電圧検出手段１５と、この生体電圧検出手段１５と前記抵抗電圧検出手段１４の信号から生体のインピ−ダンスを演算する演算手段１５を備えたものである。
【００２３】
上記参考例１において、高周波電圧発生手段１０の電圧を電圧−電流変換手段１１が定電流化する。この電流は、生体に接触している電極１２ａ，１２ｂ間に、前記電流を検出するための電流検出抵抗１３を介して流れる。電極１２ａ、１２ｂは、身体の左手と右手に接触して両手間に電流が流れる。この電流が流れることにより発生する生体の電極１２ａ，１２ｂ間の電圧を、生体電圧検出手段１５が検出する。また同様にして電流検出抵抗１３間に発生する電圧を、抵抗電圧検出手段１４が検出する。この検出した両電圧を読み込んで演算手段１６は生体インピ−ダンスＺを演算するのである。すなわち、抵抗電圧検出手段１４の検出した電圧Ｖｒと、電流検出抵抗１３の抵抗値Ｒから生体に流れる電流Ｉを常に求める。この電流Ｉを用いて生体電圧Ｖｚから生体インピ−ダンスを求めることができる。
【００２４】
特に本参考例１では、生体インピ−ダンス測定時の電流Ｉを常に検出して生体インピ−ダンスを演算するので、精度の高い生体インピ−ダンスの測定装置を実現できる。
【００２５】
なお、参考例１では、高周波電圧発生手段１０の周波数に５０ｋＨｚを用いたが、１０ｋＨｚから５００ｋＨｚ等の周波数でも同様の効果が得られ、単一周波数に限られるものではない。
【００２６】
（実施例１）
図２は、生体インピ−ダンス測定装置の実施例１を示すブロック図である。この生体インピ−ダンス測定装置は、電極間を短絡するスイッチと演算手段の入力側に差動増幅器を設けた点が参考例１と異なるだけで、それ以外の同一構成および作用効果を奏する部分には同一符号を付して詳細な説明を省略し、異なる点を中心に説明する。
【００２７】
１７は演算手段１６の入力側に接続した差動増幅器で、抵抗電圧検出手段１４と生体電圧検出手段１５との信号を差動増幅する。１８は電極１２ａ、１２ｂ間を短絡するスイッチである。
【００２８】
上記実施例１において、スイッチ１８を閉じ場合は、電圧−電流変換手段１１からの定電流は電流検出抵抗１３、電極１２ａ、スイッチ１８、電極１２ｂと流れ、差動増幅器１７への電圧Ｖｏ１は抵抗電圧検出手段１４の検出した電圧Ｖｒが出力される。この電圧Ｖｏ１より生体に流れる電流Ｉを演算して求める。次に、スイッチ１８を開いた場合、定電流は電流検出抵抗１３、電極１２ａ、生体、電極１２ｂと流れ、差動増幅器１７への電圧Ｖｏ２は、生体電圧検出手段１５の検出した電圧Ｖｚから抵抗電圧検出手段１４の検出した電圧Ｖｒとの差の電圧が出力される。そして、抵抗電圧検出手段１４と生体電圧検出手段１５から出力された電圧による差動増幅器１７からの信号で演算手段１６は生体インピ−ダンスＺを求める。すなわち、前記電圧Ｖｏ２から電圧Ｖｏ１を引き算して生体電圧Ｖｚを求める。この生体電圧Ｖｚと前記電流Ｉを用いて生体インピ−ダンスを求めることができる。
【００２９】
以上のように実施例１によれば、常に前記電圧Ｖｏ２、電圧Ｖｏ１、測定時の電流Ｉから生体インピ−ダンスＺを決定するようにしているため、定電流の変動の影響を低減でき、測定精度の高い生体インピ−ダンス装置を実現できる。
【００３０】
（実施例２）
図３は、生体インピ−ダンス測定装置の実施例２を示すブロック図である。この生体インピ−ダンス測定装置は、実施例１の電極間を短絡するスイッチを、電流検出抵抗を短絡するスイッチに変えた点が実施例１と異なるだけで、それ以外の同一構成および作用効果を奏する部分には同一符号を付して詳細な説明を省略し、異なる点を中心に説明する。１９は電流検出抵抗１３を短絡するスイッチである。
【００３１】
上記実施例２において、スイッチ１９を閉じた場合は、電圧−電流変換手段１１からの定電流は電流検出抵抗１３をバイパスしてスイッチ１９、電極１２ａ、生体、電極１２ｂと流れ、差動増幅器１７への電圧Ｖｏ１は生体電圧検出手段１５の検出した電圧Ｖｚが出力される。次に、スイッチ１９を開いた場合は、定電流は電流検出抵抗１３、電極１２ａ、生体、電極１２ｂと流れ、差動増幅器１７への電圧Ｖｏ２は、生体電圧検出手段１５の検出した電圧Ｖｚから抵抗電圧検出手段１４の検出した電圧Ｖｒとの差の電圧が出力される。そして、抵抗電圧検出手段１４と生体電圧検出手段１５から出力された電圧による差動増幅器１７からの信号により演算手段１６は生体インピ−ダンスＺを求める。すなわち、電圧Ｖｏ２から電圧Ｖｏ１を引き算して抵抗電圧Ｖｒが得られ、この電圧Ｖｒより生体に流れる電流Ｉを演算して求めている。そして、前記電圧Ｖｏ１である生体電圧Ｖｚと前記電流Ｉを用いて生体インピ−ダンスＺを求めることができる。
【００３２】
以上のように実施例２によれば、常に前記電圧Ｖｏ２、電圧Ｖｏ１、測定時の電流Ｉから生体インピ−ダンスＺを決定するようにしているため、定電流の変動の影響を低減でき、測定精度の高い生体インピ−ダンス装置を実現できる。
【００３３】
（実施例３）
図４は、生体インピ−ダンス測定装置の実施例３を示すブロック図である。この生体インピ−ダンス測定装置は、電流検出抵抗と電極間の電圧を検出する電圧検出手段と、電流検出抵抗を短絡するスイッチを設けた点が参考例１と異なるだけで、それ以外の同一構成および作用効果を奏する部分には同一符号を付して詳細な説明を省略し、異なる点を中心に説明する。
【００３４】
２０は電流検出抵抗１３と電極１２ａ，１２ｂの直列回路の電圧を検出する電圧検出手段で、２１は電流検出抵抗１３を短絡するスイッチである。
【００３５】
上記実施例３において、スイッチ１９を閉じた場合は、電圧−電流変換手段１１からの定電流は電流検出抵抗１３をバイパスしてスイッチ２１、電極１２ａ、生体、電極１２ｂと流れ、電圧検出手段２０への電圧Ｖｏ１は、生体間の電圧Ｖｚが出力される。次に、スイッチ２１を開いた場合は、定電流は電流検出抵抗１３、電極１２ａ、生体、電極１２ｂと流れ、電圧検出手段２０への電圧Ｖｏ２は、生体間の電圧Ｖｚと電流検出抵抗１３の電圧Ｖｒとの和の電圧が出力される。そして、電圧検出手段２０を介し前記両方の出力電圧を受けた演算手段１６は生体インピ−ダンスＺを求める。すなわち、前記電圧Ｖｏ２から電圧Ｖｏ１を引くことにより、電流検出抵抗１３の電圧Ｖｒが得られ、この電圧Ｖｒより生体に流れる電流Ｉを演算して求めている。そして、前記電圧Ｖｏ１である生体電圧Ｖｚと前記電流Ｉを用いて生体インピ−ダンスＺを求めることができる。
【００３６】
以上のように実施例３によれば、常に前記電圧Ｖｏ１、電圧Ｖｏ２、測定時の電流Ｉから生体インピ−ダンスＺを決定するようにしているため、定電流の変動の影響を低減でき、測定精度の高い生体インピ−ダンス装置を実現できる。
【００３７】
（実施例４）
図５は、生体インピ−ダンス測定装置の実施例４を示すブロック図である。この生体インピ−ダンス測定装置は、実施例３の電流検出抵抗を短絡するスイッチを、電極間を短絡するスイッチに変えた点が実施例３と異なるだけで、それ以外の同一構成および作用効果を奏する部分には同一符号を付して詳細な説明を省略し、異なる点を中心に説明する。２２は電極１２ａ、１２ｂ間を短絡するスイッチである。
【００３８】
上記実施例４において、スイッチ２２を閉じた場合は、電圧−電流変換手段１１からの定電流は電流検出抵抗１３、電極１２ａ、スイッチ２２、電極１２ｂと流れ、電圧検出手段２０への電圧Ｖｏ１は、電流検出抵抗１３の電圧Ｖｒが出力される。この電圧Ｖｏ１より生体に流れる電流Ｉを演算して求める。次に、スイッチ２２を開いた場合は、定電流は電流検出抵抗１３、電極１２ａ、生体、電極１２ｂと流れ、電圧検出手段２０への電圧Ｖｏ２は、生体間の電圧Ｖｚと電流検出抵抗１３の電圧Ｖｒとの和の電圧が出力される。そして、前記両方の出力電圧を受けた電圧検出手段２０からの信号で演算手段１６は生体インピ−ダンスＺを求める。すなわち、前記電圧Ｖｏ２から電圧Ｖｏ１を引くことにより、生体電圧Ｖｚが得られ、この電圧Ｖｚと前記電流Ｉを用いて生体インピ−ダンスＺを求めることができる。
【００３９】
以上のように実施例４によれば、常に前記電圧Ｖｏ１、電圧Ｖｏ２、測定時の電流Ｉから生体インピ−ダンスＺを決定するようにしているため、定電流の変動の影響を低減でき、測定精度の高い生体インピ−ダンス装置を実現できる。
【００４０】
（実施例５）
図６は、生体インピ−ダンス測定装置の実施例５を示すブロック図である。この生体インピ−ダンス測定装置は、電流検出抵抗と並列に、抵抗とスイッチの直列回路を設けた点が参考例１と異なるだけで、それ以外の同一構成および作用効果を奏する部分には同一符号を付して詳細な説明を省略し、異なる点を中心に説明する。
【００４１】
２３は抵抗値が電流検出抵抗１３と異なる抵抗で、直列に接続したスイッチ２４を介して電流検出抵抗１３と並列結線している。
【００４２】
上記実施例５において、スイッチ２４を開いた場合は、電圧−電流変換手段１１からの定電流は電流検出抵抗１３、電極１２ａ、生体、電極１２ｂと流れ、抵抗電圧検出手段１４への電圧Ｖｏ１は、電流検出抵抗１３の電圧Ｖｒ１が出力される。また、スイッチ２４を閉じた場合は、定電流が電流検出抵抗１３と抵抗２３に分流し、更に電極１２ａ、生体、電極１２ｂと流れ、抵抗電圧検出手段１４への電圧Ｖｏ２は、電流検出抵抗１３と抵抗２３の並列抵抗による電圧が出力される。この前記両方の電圧Ｖｏ１とＶｏ２を受けた抵抗電圧検出手段１４の信号で演算手段１６は生体に流れる電流Ｉを演算して求めている。
【００４３】
一方、生体電圧検出手段１５には、生体電圧Ｖｚが出力される。この生体電圧Ｖｚと前記電流Ｉを用いて演算手段１６は生体インピ−ダンスＺを求めることができる。
【００４４】
以上のように実施例５によれば、２値の電流検出抵抗の電圧から測定時の電流Ｉの相関式を算出して、生体インピ−ダンスＺを決定するようにしているため、定電流の変動の影響を低減でき、測定精度の高い生体インピ−ダンス装置を実現できる。
【００４５】
（実施例６）
図７は、生体インピ−ダンス測定装置の実施例６を示すブロック図である。この生体インピ−ダンス測定装置は、電極接触検知手段を設けた点が実施例１と異なるだけで、それ以外の同一構成および作用効果を奏する部分には同一符号を付して詳細な説明を省略し、異なる点を中心に説明する。
【００４６】
２５は生体電圧検知手段１５の信号により電極１２ａ、１２ｂが生体に接触したことを検知する電極接触検知手段である。
【００４７】
上記実施例６において、電極１２ａ、１２ｂを生体に接触させると、生体電圧検知手段１５が前記電極間の電圧を検出し、この電圧レベルで電極接触検知手段２５が電極１２ａ，１２ｂの接触度を判定する。すなわち、電極１２ａ，１２ｂが生体に接触不十分の場合、生体と電極１２ａ，１２ｂ間に接触抵抗が発生し、生体電圧検知手段１５の出力電圧は高くなる。また、電極１２ａ，１２ｂが生体に確実に接触した場合、所定の生体インピ−ダンスによる電圧値となる。つまり、電極接触検知手段２５が、所定の電圧範囲にあることを判定して、生体インピ−ダンスの測定を開始することができる。そして、設定の回数繰り返すことによって複数の測定結果が得られ、これを処理することによりデ−タの精度を向上できるものである。
【００４８】
なお、上記実施例６において、電極の生体との接触を検知するのに電極接触検知手段２５は、電極１２ａ、１２ｂ間の生体電圧検知手段１５の信号を用いているが、電流検出抵抗１３の抵抗電圧検知手段１４の信号を用いても同様の効果が得られるものである。
【００４９】
【発明の効果】
以上のように本発明の請求項１に記載の発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、抵抗電圧検出手段と生体電圧検出手段の信号を差動増幅する差動増幅手段と、電極間を短絡するスイッチを備えたもので、スイッチの開閉による生体に流れる電流を電流検出抵抗により検出して生体インピ−ダンスＺを演算しているため、定電流の変動の影響を低減でき、測定精度の高い装置を実現できる。
【００５０】
また、請求項２に記載した発明は、請求項１記載において電流検出抵抗を短絡するスイッチを備えたもので、スイッチの開閉による生体に流れる電流を電流検出抵抗により検出して生体インピ−ダンスＺを演算しているため、定電流の変動の影響を低減でき、測定精度の高い装置を実現できる。
【００５１】
また、請求項３に記載した発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、電流検出抵抗と電極間との電圧を検出する電圧検出手段と、電流検出抵抗を短絡するスイッチを備えたもので、スイッチの開閉による生体に流れる電流を電流検出抵抗により検出して生体インピ−ダンスＺを演算しているため、定電流の変動の影響を低減でき、測定精度の高い装置を実現できる。
【００５２】
また、請求項４に記載の発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、電流検出抵抗と電極間との電圧を検出する電圧検出手段と、電極間を短絡するスイッチを備えたもので、スイッチの開閉による生体に流れる電流を電流検出抵抗により検出して生体インピ−ダンスＺを演算しているため、定電流の変動の影響を低減でき、測定精度の高い装置を実現できる。
【００５３】
また、請求項５に記載した発明は、高周波電圧発生手段と、この高周波電圧発生手段の電圧を電流に変換する電圧−電流変換手段と、生体に接触する電極と、この電極に流れる電流を検出する電流検出抵抗と、この電流検出抵抗の電圧を検出する抵抗電圧検出手段と、前記電極間の生体の電圧を検出する生体電圧検出手段と、この生体電圧検出手段と前記抵抗電圧検出手段の信号から生体のインピ−ダンスを算出する演算手段と、抵抗値が電流検出抵抗と異なる抵抗と、この抵抗を前記電流検出抵抗に並列に接続するスイッチを備えたもので、スイッチの開閉による生体に流れる電流を電流検出抵抗により検出して生体インピ−ダンスＺを演算しているため、定電流の変動の影響を低減でき、測定精度の高い装置を実現できる。
【００５４】
また、請求項６に記載した発明は、請求項１〜請求項５のいずれか１項に記載の生体電圧検出手段の信号により電極が生体に接触したことを検知する電極接触検知手段を備えたもので、生体への電極の接触度を検知して自動的に測定を開始できる。
【図面の簡単な説明】
【図１】本発明の参考例１における生体インピ−ダンス測定装置を示すブロック図
【図２】同実施例１における生体インピ−ダンス測定装置を示すブロック図
【図３】同実施例２における生体インピ−ダンス測定装置を示すブロック図
【図４】同実施例３における生体インピ−ダンス測定装置を示すブロック図
【図５】同実施例４における生体インピ−ダンス測定装置を示すブロック図
【図６】同実施例５における生体インピ−ダンス測定装置を示すブロック図
【図７】同実施例６における生体インピ−ダンス測定装置を示すブロック図
【図８】従来例における生体インピ−ダンス測定装置を示すブロック図
【符号の説明】
１０高周波電圧発生手段
１１電圧−電流変換手段
１２ａ電極
１２ｂ電極
１３電流検出抵抗
１４抵抗電圧検出手段
１５生体電圧検出手段
１６演算手段
１７差動増幅器
１８スイッチ
１９スイッチ
２０電圧検出手段
２１スイッチ
２２スイッチ
２３抵抗
２４スイッチ
２５電極接触検知手段[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a living body such as a body fat meter that measures the impedance of a living body by applying a high-frequency current to the living body and calculates the body fat mass in the body from the body impedance and body conditions such as body weight. The present invention relates to an apparatus for measuring the impedance.
[0002]
[Prior art]
  In general, as a method for measuring the amount of fat in the body, the impedance between the ends of the body, such as between both hands, is measured by a four-terminal method, and the amount of fat in the body is calculated from the body information such as height and weight. A method has been proposed.
[0003]
  FIG. 8 is a block diagram showing a configuration of a conventional biological impedance measuring apparatus. In the measurement of the biological impedance, a sine wave of 50 kHz is generated from the transmitter 1 and the voltage of this sine wave is converted to a constant current by the voltage-current conversion means 2. This constant current is passed through the living body from between the electrodes 3a and 3b that are in contact with the living body. Then, the voltage between the electrodes 3a and 3b is taken out by the differential amplifier 4, the waveform is shaped by a filter circuit or the like, converted into direct current by the rectifier 5, and then converted from analog values to digital values by the AD converter 6. The data is transmitted to the calculation unit 7 composed of a microcomputer. The calculation unit 7 calculates the biological impedance from the voltage signal.
[0004]
  The biological impedance Z can be obtained by detecting the electrode voltage V when the current I is constant when Z = V / I in the relationship between the biological current I and the electrode voltage V. it can. The amount of fat in the body is calculated from the body impedance Z and body information such as height and weight.
[0005]
[Problems to be solved by the invention]
  In the living body impedance measuring apparatus having the conventional configuration, when the constant current source changes due to an environment such as temperature, the change in the constant current causes a measurement error of the living body impedance. In order to set the constant current source to a steady value, a great deal of labor is required for reducing external environmental fluctuations and improving the accuracy of the constant current source.
[0006]
  The present invention solves the above-mentioned conventional problems, and provides a living body impedance measuring device capable of detecting a living body current at the time of measurement and performing highly accurate measurement without being affected by an environment such as temperature.
[0007]
[Means for Solving the Problems]
  The present invention includes a high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with a living body, a current detection resistor for detecting a current flowing through the electrode, Resistance voltage detection means for detecting the voltage of the current detection resistor, biological voltage detection means for detecting the voltage of the living body between the electrodes, and the impedance of the living body from the signals of the biological voltage detection means and the resistance voltage detection means It is provided with the calculating means to calculate.
[0008]
  In the above means, since the current value is obtained by detecting the current flowing through the living body with the current detection resistor, it is possible to perform highly accurate measurement that is not affected by the external environment such as temperature.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
  According to the first aspect of the present invention, the high-frequency voltage generating means, the voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, the electrode in contact with the living body, and the current flowing through the electrode A current detecting resistor for detecting, a resistance voltage detecting means for detecting a voltage of the current detecting resistor, a living body voltage detecting means for detecting a living body voltage between the electrodes, a living body voltage detecting means and the resistance voltage detecting means; Calculation means for calculating impedance of living body from signalA differential amplifying means for differentially amplifying signals from the resistance voltage detecting means and the biological voltage detecting means, and a switch for short-circuiting the electrodes.It is a thing.
[0010]
  In the above embodiment, the voltage of the high frequency voltage generating means is made constant by the voltage-current converting means. The constant current flows to the living body through the current detection resistor and the electrode, and the calculation means calculates the living body impedance from the voltage of the current detection resistor generated by this current and the voltage between the electrodes. Therefore, the calculation of the living body impedance is performed by always detecting the current flowing through the living body from the resistance of the current detection resistor, so that the accuracy of the living body impedance measurement can be improved.. In addition, when the switch is closed, the voltage Vo1 is generated only by the current detection resistor generated by the constant current flowing. When the switch is opened, the constant current flows to the living body through the current detection resistor and the electrode. The difference from the detected voltage Vo2 is detected by a differential amplifier, and the calculation means calculates the biological impedance from this detection signal. Accordingly, the calculation of the living body impedance is always performed by detecting the current flowing through the living body from the current I at the time of measurement, the voltage Vo1, and the voltage Vo2. Improve impedance measurement accuracy.
[0011]
  Claims2The invention described in claim 11In the description, a switch for short-circuiting the current detection resistor is provided.
[0012]
  In the above embodiment, when the switch is closed, the voltage Vo1 between the living body electrodes generated by a constant current flowing through the electrode, and when the switch is opened, the current is fixed to the living body via the current detection resistor and the electrode. When the current flows, the difference from the generated voltage Vo2 is detected by a differential amplifier, and the calculation means calculates the biological impedance from this detection signal. Accordingly, since the biological impedance is calculated by always detecting the current I flowing during measurement and the current flowing through the living body from the voltage Vo1 and the voltage Vo2, the accuracy of the biological impedance measurement can be improved.
[0013]
  Claims3The invention described inA high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means When,A voltage detection means for detecting the voltage between the current detection resistor and the electrode and a switch for short-circuiting the current detection resistor are provided.
[0014]
  In the above embodiment, when the switch is closed, the voltage Vo1 between the living body electrodes generated when a constant current flows to the living body through the electrode, and when the switch is opened, the constant current is the current detection resistor and the electrode. The calculating means calculates the living body impedance from the voltage Vo1 of the sum of the voltages generated by flowing into the living body via the. Accordingly, since the biological impedance is calculated by always detecting the current I flowing during measurement and the current flowing through the living body from the voltage Vo1 and the voltage Vo2, the accuracy of the biological impedance measurement can be improved.
[0015]
  Claims4The invention described inA high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means When,A voltage detection means for detecting a voltage between the current detection resistor and the electrode and a switch for short-circuiting the electrodes are provided.
[0016]
  In the above embodiment, when the switch is closed, the voltage Vo1 of only the current detection resistor generated by the constant current flowing, and when the switch is open, the current detection resistor and the biological electrode generated by the constant current flowing The computing means computes the biological impedance from the voltage Vo2 which is the sum of the voltages between the two. Accordingly, since the biological impedance is calculated by always detecting the current I flowing during measurement and the current flowing through the living body from the voltage Vo1 and the voltage Vo2, the accuracy of the biological impedance measurement can be improved.
[0017]
  Claims5The invention described inA high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means When,A resistor having a resistance value different from that of the current detection resistor and a switch for connecting the resistor in parallel with the current detection resistor are provided.
[0018]
  In the above embodiment, when the switch is closed, a constant current flows between the current detection resistor, the resistor and the electrode, and the voltage Vo2 of the parallel circuit of the current detection resistor and the resistor is generated. The computing means computes the biological impedance from the voltage difference between the voltage Vo1 whose current is only the current detection resistor and the voltage between the biological electrodes generated by the constant current flowing through the electrodes. Accordingly, since the biological impedance is calculated by always detecting the current I flowing during measurement and the current flowing through the living body from the voltage Vo1 and the voltage Vo2, the accuracy of the biological impedance measurement can be improved.
[0019]
  Claims6The invention described in claim 1 to claim 15The electrode contact detection means which detects that the electrode contacted the living body by the signal of the biological voltage detection means described in any one of the above.
[0020]
  In the said form, an electrode contact detection means detects a contact degree of the electrode to a biological body by obtaining a signal from a biological voltage detection means. Therefore, the accuracy of the biological impedance measurement can be improved by repeating the number of measurements..
[0021]
【Example】
  Hereinafter, the biological impedance measuring apparatus of the present invention will be described with reference to FIGS.
[0022]
  (referenceExample 1)
  FIG. 1 shows a biological impedance measuring apparatus.reference1 is a block diagram showing the invention of Example 1. FIG. This living body impedance measuring apparatus includes a high frequency voltage generating means 10 that generates a 50 kHz sine wave, a voltage-current converting means 11 that converts the voltage of the high frequency voltage generating means 10 into a current, and an electrode 12a that contacts the living body. , 12b, a current detection resistor 13 for detecting the current flowing through the electrodes 12a, 12b, a resistance voltage detection means 14 for detecting the voltage of the current detection resistor 13, and a living body voltage between the electrodes 12a, 12b. And a calculating means 15 for calculating the impedance of the living body from the signals of the living body voltage detecting means 15 and the resistance voltage detecting means 14.
[0023]
  the abovereferenceIn Example 1, the voltage-current converting means 11 makes the voltage of the high-frequency voltage generating means 10 constant. This current flows between the electrodes 12a and 12b in contact with the living body via the current detection resistor 13 for detecting the current. The electrodes 12a and 12b are in contact with the left and right hands of the body, and a current flows between both hands. The biological voltage detection means 15 detects the voltage between the biological electrodes 12a and 12b generated by the flow of this current. Similarly, the resistance voltage detection means 14 detects the voltage generated between the current detection resistors 13. The calculation means 16 calculates the biological impedance Z by reading both detected voltages. That is, the current I flowing through the living body is always obtained from the voltage Vr detected by the resistance voltage detector 14 and the resistance value R of the current detection resistor 13. By using this current I, the biological impedance can be obtained from the biological voltage Vz.
[0024]
  Especially booksreferenceIn Example 1, since the living body impedance is calculated by always detecting the current I during the living body impedance measurement, a highly accurate living body impedance measuring apparatus can be realized.
[0025]
  In addition,referenceIn Example 1, 50 kHz is used as the frequency of the high-frequency voltage generating means 10, but the same effect can be obtained even at a frequency of 10 kHz to 500 kHz, and the frequency is not limited to a single frequency.
[0026]
  (Example1)
  FIG. 2 shows an embodiment of a biological impedance measuring device.1FIG. This bioimpedance measuring device is characterized in that a switch for short-circuiting the electrodes and a differential amplifier are provided on the input side of the arithmetic means.referenceOnly the differences from Example 1 will be described, with the same reference numerals assigned to other parts having the same configuration and operational effects, and detailed description thereof omitted.
[0027]
  Reference numeral 17 denotes a differential amplifier connected to the input side of the arithmetic means 16, which differentially amplifies signals from the resistance voltage detection means 14 and the biological voltage detection means 15. Reference numeral 18 denotes a switch for short-circuiting the electrodes 12a and 12b.
[0028]
  Example above1When the switch 18 is closed, the constant current from the voltage-current conversion means 11 flows through the current detection resistor 13, the electrode 12a, the switch 18, and the electrode 12b, and the voltage Vo1 to the differential amplifier 17 is the resistance voltage detection means 14. The detected voltage Vr is output. The current I flowing through the living body is calculated from this voltage Vo1. Next, when the switch 18 is opened, a constant current flows through the current detection resistor 13, the electrode 12 a, the living body, and the electrode 12 b, and the voltage Vo 2 to the differential amplifier 17 is resistance from the voltage Vz detected by the living body voltage detection means 15. A difference voltage from the voltage Vr detected by the voltage detection means 14 is output. Then, the computing means 16 obtains the biological impedance Z by the signal from the differential amplifier 17 based on the voltages output from the resistance voltage detecting means 14 and the biological voltage detecting means 15. That is, the biological voltage Vz is obtained by subtracting the voltage Vo1 from the voltage Vo2. The bioelectrical impedance can be obtained using the bioelectric voltage Vz and the current I.
[0029]
  Examples as above1Since the living body impedance Z is always determined from the voltage Vo2, the voltage Vo1, and the current I at the time of measurement, the influence of the fluctuation of the constant current can be reduced and the living body impedance with high measurement accuracy. A device can be realized.
[0030]
  (Example2)
  FIG. 3 shows an embodiment of a biological impedance measuring device.2FIG. This living body impedance measuring apparatus is1The point that changed the switch that short-circuits between the electrodes to the switch that short-circuits the current detection resistor is an example1The other parts having the same configuration and operational effects are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be mainly described. A switch 19 short-circuits the current detection resistor 13.
[0031]
  Example above2When the switch 19 is closed, the constant current from the voltage-current conversion means 11 bypasses the current detection resistor 13 and flows through the switch 19, the electrode 12a, the living body, and the electrode 12b, and the voltage Vo1 to the differential amplifier 17 is supplied. The voltage Vz detected by the biological voltage detection means 15 is output. Next, when the switch 19 is opened, a constant current flows through the current detection resistor 13, the electrode 12 a, the living body, and the electrode 12 b, and the voltage Vo 2 to the differential amplifier 17 is determined from the voltage Vz detected by the living body voltage detecting means 15. A difference voltage from the voltage Vr detected by the resistance voltage detection means 14 is output. Then, the computing means 16 obtains the biological impedance Z based on signals from the differential amplifier 17 based on the voltages output from the resistance voltage detecting means 14 and the biological voltage detecting means 15. That is, the resistance voltage Vr is obtained by subtracting the voltage Vo1 from the voltage Vo2, and the current I flowing through the living body is calculated from the voltage Vr. Then, the living body impedance Z can be obtained using the living body voltage Vz which is the voltage Vo1 and the current I.
[0032]
  Examples as above2Since the living body impedance Z is always determined from the voltage Vo2, the voltage Vo1, and the current I at the time of measurement, the influence of the fluctuation of the constant current can be reduced and the living body impedance with high measurement accuracy. A device can be realized.
[0033]
  (Example3)
  FIG. 4 shows an embodiment of a biological impedance measuring device.3FIG. This biological impedance measuring device is provided with a voltage detection means for detecting a voltage between the current detection resistor and the electrode, and a switch for short-circuiting the current detection resistor.referenceOnly the differences from Example 1 will be described, with the same reference numerals assigned to other parts having the same configuration and operational effects, and detailed description thereof omitted.
[0034]
  Reference numeral 20 denotes voltage detection means for detecting the voltage of the series circuit of the current detection resistor 13 and the electrodes 12a and 12b, and reference numeral 21 denotes a switch for short-circuiting the current detection resistor 13.
[0035]
  Example above3When the switch 19 is closed, the constant current from the voltage-current conversion unit 11 bypasses the current detection resistor 13 and flows through the switch 21, the electrode 12a, the living body, and the electrode 12b, and the voltage Vo1 to the voltage detection unit 20 is detected. Outputs a voltage Vz between the living bodies. Next, when the switch 21 is opened, the constant current flows through the current detection resistor 13, the electrode 12 a, the living body, and the electrode 12 b, and the voltage Vo 2 to the voltage detection means 20 is the voltage Vz between the living body and the current detection resistor 13. A voltage summed with the voltage Vr is output. Then, the calculation means 16 that has received both the output voltages via the voltage detection means 20 obtains the biological impedance Z. That is, the voltage Vr of the current detection resistor 13 is obtained by subtracting the voltage Vo1 from the voltage Vo2, and the current I flowing through the living body is calculated from the voltage Vr. Then, the living body impedance Z can be obtained using the living body voltage Vz which is the voltage Vo1 and the current I.
[0036]
  Examples as above3Since the living body impedance Z is always determined from the voltage Vo1, the voltage Vo2, and the current I at the time of measurement, the influence of the fluctuation of the constant current can be reduced and the living body impedance with high measurement accuracy. A device can be realized.
[0037]
  (Example4)
  FIG. 5 shows an embodiment of a biological impedance measuring device.4FIG. This living body impedance measuring apparatus is3The switch that short-circuited the current detection resistor of the circuit was changed to a switch that short-circuited the electrodes.3The other parts having the same configuration and operational effects are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be mainly described. A switch 22 short-circuits between the electrodes 12a and 12b.
[0038]
  Example above4When the switch 22 is closed, the constant current from the voltage-current conversion unit 11 flows through the current detection resistor 13, the electrode 12a, the switch 22, and the electrode 12b, and the voltage Vo1 to the voltage detection unit 20 is the current detection resistor. 13 voltage Vr is output. The current I flowing through the living body is calculated from this voltage Vo1. Next, when the switch 22 is opened, the constant current flows through the current detection resistor 13, the electrode 12 a, the living body, and the electrode 12 b, and the voltage Vo 2 to the voltage detection means 20 is the voltage Vz between the living body and the current detection resistor 13. A voltage summed with the voltage Vr is output. Then, the calculation means 16 obtains the biological impedance Z based on the signals from the voltage detection means 20 that have received both the output voltages. That is, the biological voltage Vz is obtained by subtracting the voltage Vo1 from the voltage Vo2, and the biological impedance Z can be obtained using the voltage Vz and the current I.
[0039]
  Examples as above4Since the living body impedance Z is always determined from the voltage Vo1, the voltage Vo2, and the current I at the time of measurement, the influence of the fluctuation of the constant current can be reduced and the living body impedance with high measurement accuracy. A device can be realized.
[0040]
  (Example5)
  FIG. 6 shows an embodiment of a biological impedance measuring device.5FIG. This biological impedance measuring device is provided with a series circuit of a resistor and a switch in parallel with the current detection resistor.referenceOnly the differences from Example 1 will be described, with the same reference numerals assigned to other parts having the same configuration and operational effects, and detailed description thereof omitted.
[0041]
  Reference numeral 23 denotes a resistor having a resistance value different from that of the current detection resistor 13, and is connected in parallel to the current detection resistor 13 through a switch 24 connected in series.
[0042]
  Example above5When the switch 24 is opened, the constant current from the voltage-current conversion means 11 flows through the current detection resistor 13, the electrode 12a, the living body, and the electrode 12b, and the voltage Vo1 to the resistance voltage detection means 14 is the current detection resistance. 13 voltage Vr1 is output. When the switch 24 is closed, a constant current is shunted to the current detection resistor 13 and the resistor 23, and further flows to the electrode 12a, the living body, and the electrode 12b, and the voltage Vo2 to the resistance voltage detection means 14 is And a voltage due to the parallel resistance of the resistor 23 is output. The calculating means 16 calculates and obtains the current I flowing through the living body based on the signal of the resistance voltage detecting means 14 that has received both the voltages Vo1 and Vo2.
[0043]
  On the other hand, the biological voltage detection unit 15 outputs the biological voltage Vz. Using this biological voltage Vz and the current I, the calculation means 16 can determine the biological impedance Z.
[0044]
  Examples as above5According to the above, since the correlation equation of the current I at the time of measurement is calculated from the voltage of the binary current detection resistor and the biological impedance Z is determined, the influence of the fluctuation of the constant current can be reduced, A biological impedance apparatus with high measurement accuracy can be realized.
[0045]
  (Example6)
  FIG. 7 shows an embodiment of a biological impedance measuring device.6FIG. This living body impedance measuring apparatus is different from the first embodiment only in that an electrode contact detecting means is provided, and other parts having the same configuration and operational effects are denoted by the same reference numerals and detailed description thereof is omitted. However, the differences will be mainly described.
[0046]
  Reference numeral 25 denotes an electrode contact detection means for detecting that the electrodes 12a and 12b have contacted the living body based on a signal from the biological voltage detection means 15.
[0047]
  Example above6When the electrodes 12a and 12b are brought into contact with the living body, the living body voltage detecting means 15 detects the voltage between the electrodes, and the electrode contact detecting means 25 determines the degree of contact between the electrodes 12a and 12b at this voltage level. That is, when the electrodes 12a and 12b are not sufficiently in contact with the living body, contact resistance is generated between the living body and the electrodes 12a and 12b, and the output voltage of the living body voltage detecting means 15 is increased. Further, when the electrodes 12a and 12b are surely in contact with the living body, the voltage value is determined by a predetermined living body impedance. That is, the electrode contact detection means 25 can determine that the voltage is within a predetermined voltage range, and can start measuring the biological impedance. A plurality of measurement results can be obtained by repeating the set number of times, and the accuracy of the data can be improved by processing these results.
[0048]
  The above example6The electrode contact detection means 25 uses the signal of the biological voltage detection means 15 between the electrodes 12a and 12b to detect the contact of the electrode with the living body, but the resistance voltage detection means 14 of the current detection resistor 13 The same effect can be obtained even if a signal is used.
[0049]
【The invention's effect】
  As described above, the invention according to claim 1 of the present invention is the high frequency voltage generating means, the voltage-current converting means for converting the voltage of the high frequency voltage generating means into current, the electrode in contact with the living body, and the electrode A current detection resistor that detects a current flowing through the electrode, a resistance voltage detection unit that detects a voltage of the current detection resistor, a biological voltage detection unit that detects a biological voltage between the electrodes, the biological voltage detection unit, and the resistance Calculation means for calculating impedance of living body from signal of voltage detection meansA differential amplifying means for differentially amplifying signals of the resistance voltage detecting means and the biological voltage detecting means, and a switch for short-circuiting the electrodesWithSince the current impedance Z is calculated by detecting the current flowing through the living body due to the opening and closing of the switch by the current detection resistor, the influence of the fluctuation of the constant current can be reduced, and a device with high measurement accuracy can be realized..
[0050]
  Claims2The invention described in claim 11In the description, a switch for short-circuiting the current detection resistor is provided, and the current flowing through the living body due to opening and closing of the switch is detected by the current detection resistor and the living body impedance Z is calculated. It can be reduced and a device with high measurement accuracy can be realized.
[0051]
  Claims3The invention described inA high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means When,A voltage detection means for detecting a voltage between the current detection resistor and the electrode, and a switch for short-circuiting the current detection resistor. A current flowing through the living body due to opening and closing of the switch is detected by the current detection resistor and the living body impedance. Since Z is calculated, the influence of constant current fluctuations can be reduced, and a device with high measurement accuracy can be realized.
[0052]
  Claims4The invention described inA high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means When,A voltage detection means for detecting the voltage between the current detection resistor and the electrode and a switch for short-circuiting between the electrodes, and a current flowing through the living body due to opening and closing of the switch is detected by the current detection resistor and the living body impedance Z Therefore, the influence of constant current fluctuations can be reduced, and a device with high measurement accuracy can be realized.
[0053]
  Claims5The invention described inA high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means When,A resistor having a resistance value different from that of the current detection resistor, and a switch for connecting the resistor in parallel with the current detection resistor. The current detection resistor detects the current flowing through the living body by opening and closing the switch, and the living body impedance. Since Z is calculated, the influence of constant current fluctuations can be reduced, and a device with high measurement accuracy can be realized.
[0054]
  Claims6The invention described in claim 1 to claim 15It is equipped with electrode contact detection means for detecting that the electrode is in contact with the living body according to the signal from the biological voltage detection means described in any one of the above, and automatically measures by detecting the degree of contact of the electrode with the living body Can start.
[Brief description of the drawings]
FIG. 1 of the present inventionreferenceThe block diagram which shows the bioelectrical impedance measuring apparatus in Example 1
FIG. 2 Example1Block diagram showing a biological impedance measuring device
FIG. 3 Example2Block diagram showing a biological impedance measuring device
FIG. 4 Example3Block diagram showing a biological impedance measuring device
FIG. 5 Example4Block diagram showing a biological impedance measuring device
FIG. 6 Example5Block diagram showing a biological impedance measuring device
FIG. 7 Example6Block diagram showing a biological impedance measuring device
FIG. 8 is a block diagram showing a biological impedance measuring apparatus in a conventional example.
[Explanation of symbols]
  10 High frequency voltage generation means
  11 Voltage-current conversion means
  12a electrode
  12b electrode
  13 Current detection resistor
  14 Resistance voltage detection means
  15 Biological voltage detection means
  16 Calculation means
  17 Differential amplifier
  18 switches
  19 switch
  20 Voltage detection means
  21 switch
  22 switch
  23 Resistance
  24 switch
  25 Electrode contact detection means

Claims

A high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means And a bioelectrical impedance measuring device comprising: differential amplifying means for differentially amplifying signals from the resistance voltage detecting means and the bioelectric voltage detecting means; and a switch for short-circuiting the electrodes .

Vivo according to claim 1, further comprising a switch for short-circuiting the current detection resistor Inpi - dancing measuring device.

A high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means And a bioelectrical impedance measuring device comprising: voltage detection means for detecting a voltage between the current detection resistor and the electrode; and a switch for short-circuiting the current detection resistor .

A high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means And a bioelectrical impedance measuring device comprising: voltage detecting means for detecting a voltage between the current detection resistor and the electrode; and a switch for short-circuiting the electrodes .

A high-frequency voltage generating means, a voltage-current converting means for converting the voltage of the high-frequency voltage generating means into a current, an electrode in contact with the living body, a current detecting resistor for detecting a current flowing through the electrode, and a current detecting resistor Resistance voltage detection means for detecting a voltage, biological voltage detection means for detecting the voltage of the living body between the electrodes, and calculation means for calculating the impedance of the living body from signals of the biological voltage detection means and the resistance voltage detection means And a resistor having a resistance value different from that of the current detection resistor, and a switch for connecting the resistor in parallel with the current detection resistor .

The living body impedance measuring device according to any one of claims 1 to 5 , further comprising an electrode contact detecting unit configured to detect that the electrode is in contact with the living body based on a signal from the living body voltage detecting unit .