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US4398541A
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Method and apparatus for measuring moisture content of skin
Assignee: PHARMACONTROL CORP A CORP OF NEW JERSEY
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Filing: 1978-05-25
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Granted: 1983-08-16
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Expires: 1998-05-25
Abstract
Abstract There are disclosed a method and an apparatus for measuring moisture content of skin. The skin surface is illuminated with polarized light incident at the Brewster angle. The degree of polarization of the light refracted within the skin and reflected out is measured. The measurement is a function of the refractive index of the skin which, in turn, is a function of the moisture content. To avoid measurement variations due to such things as skin color, output readings are in the form of a ratio of the reflected polarized light intensity to the reflected total light intensity.
Inventors
- 👤 Peter Pugliese
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:23
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/48; A61B5/4869; A61B5/4875; A61B5/0059; A61B5/44; A61B5/441; A61B5/442; A61B5/443
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
61 words
An apparatus for performing an in vivo measurement of the moisture content of animal or human skin comprising means for directing light toward a skin surface, means for detecting the degree of polarization of the light reflected from said skin surface, and means for determining the moisture content of the skin in accordance with the detected degree of reflected light polarization.
Claim 2
Independent Claim
61 words
An apparatus for performing an in vivo measurement of the moisture content of animal or human skin comprising means for directing light toward a skin surface, means for detecting the degree of polarization of the light reflected from said skin surface, and means for determining the moisture content of the skin in accordance with the detected degree of reflected light polarization.
Claim 3
Dependent Claim
57 words
An apparatus in accordance with claim 1 wherein said determining means includes means for measuring the total light reflected from said skin surface, and means for forming a ratio one of whose factors is proportional to the detected degree of reflected light polarization and the other of whose factors is proportional to the measured total reflected light.
Claim 4
Dependent Claim
13 words
An apparatus in accordance with claim 2 wherein said directed light is polarized.
Claim 5
Dependent Claim
26 words
An apparatus in accordance with claim 3 wherein said directed light is incident at approximately the Brewster angle to the normal line through the skin surface.
Claim 6
Dependent Claim
28 words
An apparatus in accordance with claim 3 wherein said directed light is incident to the normal line through the skin surface at an angle in the range 45°-60°.
Claim 7
Dependent Claim
20 words
An apparatus in accordance with claim 5 wherein the wavelengths in said directed light are in the range 450-700 nanometers.
Claim 8
Dependent Claim
13 words
An apparatus in accordance with claim 1 wherein said directed light is polarized.
Claim 9
Dependent Claim
28 words
An apparatus in accordance with claim 7 wherein said directed light is incident to the normal line through the skin surface at an angle in the range 45°-60°.
Claim 10
Dependent Claim
20 words
An apparatus in accordance with claim 8 wherein the wavelengths in said directed light are in the range 450-700 nanometers.
Claim 11
Dependent Claim
19 words
An apparatus in accordance with claim 1 wherein the wavelengths in said directed light are centered around 700 nanometers.
Claim 12
Dependent Claim
55 words
An in vivo method for measuring the moisture content of animal or human skin comprising the steps of directing light toward a skin surface, detecting the degree of polarization of the light reflected from said skin surface, and determining the moisture content of the skin in accordance with the detected degree of reflected light polarization.
Claim 13
Dependent Claim
55 words
An in vivo method for measuring the moisture content of animal or human skin comprising the steps of directing light toward a skin surface, detecting the degree of polarization of the light reflected from said skin surface, and determining the moisture content of the skin in accordance with the detected degree of reflected light polarization.
Claim 14
Dependent Claim
56 words
A method in accordance with claim 1 wherein said determining step includes the sub-steps of measuring the total light reflected from said skin surface, and forming a ratio one of whose factors is proportional to the detected degree of reflected light polarization and the other of whose factors is proportional to the measured total reflected light.
Claim 15
Dependent Claim
13 words
A method in accordance with claim 12 wherein said directed light is polarized.
Claim 16
Dependent Claim
26 words
A method in accordance with claim 13 wherein said directed light is incident at approximately the Brewster angle to the normal line through the skin surface.
Claim 17
Dependent Claim
28 words
A method in accordance with claim 13 wherein said directed light is incident to the normal line through the skin surface at an angle in the range 45°-60°.
Claim 18
Dependent Claim
20 words
A method in accordance with claim 15 wherein the wavelengths in said directed light are in the range 450-700 nanometers.
Claim 19
Dependent Claim
13 words
A method in accordance with claim 11 wherein said directed light is polarized.
Claim 20
Dependent Claim
28 words
A method in accordance with claim 17 wherein said directed light is incident to the normal line through the skin surface at an angle in the range 45°-60°.
Claim 21
Dependent Claim
20 words
A method in accordance with claim 18 wherein the wavelengths in said directed light are in the range 450-700 nanometers.
Claim 22
Dependent Claim
19 words
A method in accordance with claim 11 wherein the wavelengths in said directed light are centered around 700 nanometers.
Claim 23
Dependent Claim
89 words
An in vivo method for measuring the moisture content of animal or human skin comprising the steps of directing light toward a skin surface, measuring the intensity of light reflected from said skin surface, selectively placing analyzing means in the path of said reflected light to permit the taking of a first measurement indicative of the degree of polarization of said reflected light and the taking of a second measurement indicative of the total reflected light, and determining a ratio whose two factors are said first and second measurements.
Claim 24
Dependent Claim
89 words
An in vivo method for measuring the moisture content of animal or human skin comprising the steps of directing light toward a skin surface, measuring the intensity of light reflected from said skin surface, selectively placing analyzing means in the path of said reflected light to permit the taking of a first measurement indicative of the degree of polarization of said reflected light and the taking of a second measurement indicative of the total reflected light, and determining a ratio whose two factors are said first and second measurements.
Claim 25
Dependent Claim
13 words
A method in accordance with claim 21 wherein said directed light is polarized.
Claim 26
Dependent Claim
26 words
A method in accordance with claim 22 wherein said directed light is incident at approximately the Brewster angle to the normal line through the skin surface.
Claim 27
Dependent Claim
28 words
A method in accordance with claim 22 wherein said directed light is incident to the normal line through the skin surface at an angle in the range 45°-60°.
Claim 28
Dependent Claim
20 words
A method in accordance with claim 24 wherein the wavelengths in said directed light are in the range 450-700 nanometers.
Claim 29
Dependent Claim
19 words
A method in accordance with claim 25 wherein the wavelengths in said directed light are centered around 700 nanometers.
Claim 30
Dependent Claim
19 words
A method in accordance with claim 21 wherein the wavelengths in said directed light are centered around 700 nanometers.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |