Measurement of moisture content in skin
First Claim
1. A method for measuring the moisture content in skin, comprising:
- contacting the skin with three electrodes, wherein at least one measuring electrode is placed on the skin where the moisture has to be measured and the remaining two electrodes on the skin adjacent thereto;
applying a periodic voltage with a frequency of less than 50 kHz to the electrodes; and
measuring the susceptance in the skin under at least one electrode.
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Abstract
In order to measure the moisture content in skin, especially in the keratinous layer (stratum corneum), at least two electrodes are employed, at least one of which electrodes is placed on the skin where moisture has to be measured, the electrodes are supplied with a periodic voltage with a frequency of less than 50 kHz, and the susceptance in the keratinous layer is measured beneath the electrode or electrodes. In an apparatus for measuring the moisture content in skin three electrodes are employed, a periodic voltage being applied to two of these. The susceptance is measured below one of the electrodes, uninfluenced by the other electrodes, the measurement thus being truly monopolar.
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Citations
14 Claims
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1. A method for measuring the moisture content in skin, comprising:
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contacting the skin with three electrodes, wherein at least one measuring electrode is placed on the skin where the moisture has to be measured and the remaining two electrodes on the skin adjacent thereto; applying a periodic voltage with a frequency of less than 50 kHz to the electrodes; and measuring the susceptance in the skin under at least one electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for performing a method for measuring the moisture content in skin, especially in the keratinous layer (stratus corneum), wherein three electrodes are used, wherein at least one electrode is the measurement electrode and is adapted to be placed on the skin where the moisture has to be measured, and wherein a periodic voltage with a frequency of less than 50 kHz is applied to the electrodes, wherein the apparatus comprises:
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a measuring electrode and first and second remaining electrodes, wherein the second remaining electrode is connected to an inverting input and the first remaining electrode to the output of an operational amplifier, the operational amplifier'"'"'s non-inverting input being connected to a sine voltage output of an oscillator; and wherein the measuring electrode is connected via an inverting input of a transresistance amplifier to an input of a synchronous rectifier, the synchronous rectifier'"'"'s reference input being connected to a cosine voltage output of the oscillator, whereby a susceptance signal is obtained on the output of the synchronous rectifier as a measurement signal from the measuring electrode. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification