U.S. patent application number 11/031443 was filed with the patent office on 2005-06-09 for directional coupler sensor.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Gartstein, Vladimir, Kerr, Kendal William, McCurdy, Jim Allen, Meyer, Herman William, Sherman, Faiz Feisal.
Application Number | 20050120779 11/031443 |
Document ID | / |
Family ID | 29736320 |
Filed Date | 2005-06-09 |
United States Patent
Application |
20050120779 |
Kind Code |
A1 |
Sherman, Faiz Feisal ; et
al. |
June 9, 2005 |
Directional coupler sensor
Abstract
A directional coupler sensor is provided for measuring the
moisture content of a substrate, such as hair. The sensor
incorporates a high frequency directional coupler having a pair of
generally parallel plates defining a coupling gap therebetween. A
high frequency signal generator generates an electromagnetic field
across the gap with the substrate placed across the coupling gap.
The coupled power relates to the moisture content of the substrate.
A pressure sensor is provided to ensure that the desired
compactness of the substrate across the coupling gap is achieved to
obtain accurate, reliable and consistent results.
Inventors: |
Sherman, Faiz Feisal; (West
Chester, OH) ; Gartstein, Vladimir; (Cincinnati,
OH) ; Kerr, Kendal William; (Okeana, OH) ;
Meyer, Herman William; (Cincinnati, OH) ; McCurdy,
Jim Allen; (Liberty Township, OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Assignee: |
The Procter & Gamble
Company
|
Family ID: |
29736320 |
Appl. No.: |
11/031443 |
Filed: |
January 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11031443 |
Jan 7, 2005 |
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10442503 |
May 21, 2003 |
|
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|
6854322 |
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60387474 |
Jun 10, 2002 |
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Current U.S.
Class: |
73/73 |
Current CPC
Class: |
A46B 17/00 20130101;
A45D 24/10 20130101; A45D 7/00 20130101; A45D 2044/007 20130101;
G01N 22/04 20130101; G01N 33/4833 20130101; A45D 44/00
20130101 |
Class at
Publication: |
073/073 |
International
Class: |
G01N 005/02 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. A sensor for measuring health of hair, comprising: a directional
coupler having a pair of generally parallel first and second strips
defining a coupling gap therebetween; and a high frequency signal
generator electrically coupled to said first strip and operable to
couple power to said second strip with the hair placed across said
coupling gap to thereby generate a coupled power signal in said
second strip having an amplitude related to health of the hair.
10. The sensor of claim 9 wherein the amplitude of said coupled
power signal is related to moisture content of the hair.
11. The sensor of claim 9 wherein the amplitude of said coupled
power signal is related to smoothness of the hair.
12. The sensor of claim 9 wherein the amplitude of said coupled
power signal is related to shine of said hair.
13. The sensor of claim 9 wherein the amplitude of said coupled
power signal is related to absence of frigility of the hair.
14. The sensor of claim 9 wherein the amplitude of said coupled
power signal is related to absence of fissuring of the hair.
15. The sensor of claim 9 wherein the amplitude of said coupled
power signal is related to absence of cuticular breakdown of the
hair.
16. The sensor of claim 9 further comprising a hair clamping device
supporting said directional coupler and said high frequency signal
generator, said clamping device being operable to apply a packing
pressure to the hair across said coupling gap.
17. The sensor of claim 16 further comprising a pressure sensor
supported by said hair clamping device and operable to generate a
signal related to the packing pressure applied by said hair
clamping device to the hair.
18. The sensor of claim 17 wherein said hair clamping device
comprises a pair of pivoted jaws each terminating at a remote end
thereof in a handle, wherein said directional coupler is supported
by one of said jaws and said pressure sensor is supported by said
other jaw in juxtaposition to said directional coupler.
19. The sensor of claim 9 wherein said high frequency signal
generator is operable to generate a forward power signal in said
first strip and a reverse power signal in said second strip.
20. The sensor of claim 19 further comprising a mixer circuit
electrically coupled to said first and second strips and operable
to receive said forward power signal from said first strip and said
reverse power signal from said second strip to thereby generate an
output voltage signal having a value related to health of the
hair.
21. A hair care appliance for use in grooming hair, comprising: an
elongated body portion terminating in a handle; at least one hair
styling member supported by said elongated body portion and
operable to engage the hair to effect the grooming thereof; a
directional coupler supported adjacent said hair styling member and
having a pair of generally parallel first and second strips
defining a coupling gap therebetween; and a high frequency signal
generator electrically coupled to said first strip and operable to
couple power to said second strip with the hair placed across said
coupling gap to thereby generate a coupled power signal in said
second strip having an amplitude related to health of the hair.
22. The sensor of claim 21 wherein the amplitude of said coupled
power signal is related to moisture content of the hair.
23. The sensor of claim 21 wherein the amplitude of said coupled
power signal is related to smoothness of the hair.
24. The sensor of claim 21 wherein the amplitude of said coupled
power signal is related to shine of said hair.
25. The sensor of claim 21 wherein the amplitude of said coupled
power signal is related to absence of frigility of the hair.
26. The sensor of claim 21 wherein the amplitude of said coupled
power signal is related to absence of fissuring of the hair.
27. The sensor of claim 21 wherein the amplitude of said coupled
power signal is related to absence of cuticular breakdown of the
hair.
28. The sensor of claim 21 further comprising a hair clamping
device associated with said elongated body portion and supporting
said directional coupler, said clamping device being operable to
apply a packing pressure to the hair across said coupling gap.
29. The sensor of claim 28 further comprising a pressure sensor
supported by said hair clamping device and operable to generate a
signal related to the packing pressure applied by said hair
clamping device to the hair.
30. The sensor of claim 29 wherein said hair clamping device
comprises a fixed base member supporting said directional coupler
and a movable clamp member supporting said pressure sensor in
juxtaposition to said directional coupler.
31. The sensor of claim 21 wherein said high frequency signal
generator is operable to generate a forward power signal in said
first strip and a reverse power signal in said second strip.
32. The sensor of claim 31 further comprising a mixer circuit
electrically coupled to said first and second strips and operable
to receive said forward power signal from said first strip and said
reverse power signal from said second strip to thereby generate an
output voltage signal having a value related to health of the
hair.
33. A method for measuring moisture content of a substrate,
comprising: generating an electromagnetic field through the
substrate; measuring the reactance of the substrate in response to
the electromagnetic field; and determining the moisture content of
the substrate from the measured reactance.
34. The method of claim 33 wherein the electromagnetic field is
generated by a high frequency signal source electrically coupled to
a directional coupler having a pair of generally parallel first and
second strips defining a coupling gap therebetween.
35. The method of claim 34 wherein the substrate is placed across
the coupling gap.
36. The method of claim 34 wherein the high frequency signal source
operates in the RF frequency range.
37. The method of claim 34 wherein the high frequency signal source
operates in the microwave frequency range.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/387,474, filed Jun. 10, 2002.
FIELD OF THE INVENTION
[0002] The present invention relates generally to measurement
sensors and, more particularly, to a sensor for measuring a
property of a substrate, such as the internal and external moisture
content of biological systems such as hair.
BACKGROUND OF THE INVENTION
[0003] Human hair is made up of a complex protein called
alpha-keratin. Protein molecules of the hair are arranged in
organized patterns and are held together by weak bonds, such as
hydrogen, saline and hydrophobic bonds, and stronger ionic bonds
and sulphur bridges. These bonds lend stiffness or rigidity to the
hair and enable styling of the hair with waves and curls as these
bonds are broken and then re-established in different orientations
through the styling process. As is known, styling of hair may be
accomplished by breaking the bonds by adding energy to the hair,
such as by heat with a curling iron or blow dryer, or by getting
the hair wet or damp. When the hair is wet or damp and the hydrogen
bonds are broken, the hair becomes elastic and can be stretched and
given a particular form since the position of the keratin chains
has been altered. As the hair dries, the bonds reform in different
places, maintaining the hair in its new shape. Blow-drying or
setting assists in controlling the styling process so that, once
dry, the hair will retain the form it has been given.
[0004] Hair is hydroscopic and permeable so it will absorb water
from the environment. Under normal conditions, water accounts for
about 12% to 15% of the composition of hair. Normal hair can absorb
more than 30% of its own weight in water. If the hair is damaged,
this percentage can approach 45%, however damaged hair has less
ability to retain water within the hair fibers which gives hair its
healthy appearance. As more water is absorbed within the hair fiber
due to humidity or prior damage, the hydrogen bonds may loosen so
that the hair has a decreased ability to maintain its set.
[0005] During styling, if the hair is too wet, it will not hold its
shape and water must be removed before styling will be effective.
Conversely, when the hair is too dry, the hydrogen bonds will have
already been formed and poor styling will result since the keratin
chains cannot be repositioned and set. It has previously been
determined that optimum styling results may be achieved when the
moisture of hair is in the range of approximately 30-40% by weight.
It is thus desirable to be able to tell when to begin styling
(i.e., when moisture in the hair is in a range of 30-40%) to obtain
the optimum styling results.
[0006] Likewise, it is also important to know when to stop styling
hair which has been wetted to break the hydrogen bonds. If the hair
is too dry, it will not be flexible and potential damage of the
hair may result when styling is continued. It has been determined
that the process of drying hair exhibits two stages which are
relevant to styling. In a primary drying stage, water is evaporated
from the outside of the hair fibers and no styling benefit is
achieved. In a secondary drying stage, water from inside the hair
fibers is diffused to the environment. It is during this transition
to the secondary drying stage when optimum styling of hair may be
achieved. A moisture level of about 30% is a balance between
providing enough water to disrupt the hydrogen bonds to allow the
hair to shape and not enough water that must be removed for the
hydrogen bonds to be reformed.
[0007] Moisture sensing devices have been developed in the past to
determine the moisture level in hair, and have relied on various
techniques including resistance and capacitance measurements to
obtain the desired indication. However, these methods only work
well for a known cross sectional quantity and density of the hair
being measured. As the hair density or compactness is varied, these
measurement techniques fail. Additionally, these techniques rely
primarily on the moisture content outside of the hair fiber for the
measurement, and do not have the ability to accurately measure
moisture content within hair fibers as well.
[0008] Thus, there is a need for a sensing device which can
accurately and reliably determine the moisture content of a
substrate, such as hair, including moisture both inside and outside
of the hair fiber.
SUMMARY OF THE INVENTION
[0009] The present invention overcomes the foregoing and other
shortcomings and drawbacks of moisture sensors and methods of
determining moisture content heretofore known. While the invention
will be described in connection with certain embodiments, it will
be understood that the invention is not limited to these
embodiments. On the contrary, the invention includes all
alternatives, modifications and equivalents as may be included
within the spirit and scope of the present invention.
[0010] In accordance with the principles of the present invention a
directional coupler sensor is provided for measuring the moisture
content of a substrate, such as hair. As the moisture content of a
substrate increases, so does its effective relative electrical
impedance. The sensor of the present invention is designed to
measure the relative impedance of a substrate, and from that
measurement, the moisture content of the substrate can be
determined.
[0011] The sensor of the present invention incorporates a high
frequency directional coupler having a pair of generally parallel
strips that define a coupling gap therebetween. A high frequency
signal generator is electrically coupled to one of the strips and
generates an electromagnetic field across the coupling gap to
couple power to the other strip with the substrate placed across,
i.e., generally normal to the longitudinal axis of, the coupling
gap. The signal generator is preferably operable to generate
signals in the VHF to UHF frequency ranges, although other
frequency ranges are possible as well. The VHF frequency range is
between about 30 MHz and 300 MHz, and the UHF frequency range is
between about 300 MHz and about 3 GHz. The signal generator
generates a coupled power signal in the coupled strip that has an
amplitude related to the impedance, and therefore the moisture
content of the substrate placed across the coupling gap.
[0012] In accordance with another aspect of the present invention,
a pressure sensor is provided to ensure a proper packing pressure
of the substrate placed across the coupling gap. The pressure
sensor incorporates a film transducer in one embodiment that
generates an output voltage signal that varies with the packing
pressure applied to the substrate placed across the coupling gap.
The measurement of the moisture content of the substrate is
triggered upon the crossing of a pre-set pressure threshold. This
ensures that the desired compactness of the substrate placed across
the coupling gap is achieved to obtain accurate, reliable and
consistent results. Alternatively, the packing consistency can be
achieved by a mechanical system as well. The features and
objectives of the present invention will become more readily
apparent from the following Detailed Description taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and, together with a general description of the
invention given above, and the detailed description given below,
serve to explain the invention.
[0014] FIG. 1 is a functional block diagram of a directional
coupler sensor in accordance with the principles of the present
invention;
[0015] FIG. 2A is a circuit representation of a high frequency
signal generator for use in the sensor of FIG. 1 in accordance with
one embodiment of the present invention;
[0016] FIG. 2B is a circuit representation of a directional coupler
for use in the sensor of FIG. 1 in accordance with one embodiment
of the present invention;
[0017] FIG. 2C is a circuit representation of a moisture content
detector for use in the sensor of FIG. 1 in accordance with one
embodiment of the present invention;
[0018] FIG. 2D is a circuit representation of a pressure sensor for
use in the sensor of FIG. 1 in accordance with one embodiment of
the present invention;
[0019] FIG. 2E is a circuit representation of a voltage regulator
for use in the sensor of FIG. 1 in accordance with one embodiment
of the present invention;
[0020] FIG. 3 is a top plan view of the sensor of FIG. 1 shown
integrated onto a printed circuit board;
[0021] FIG. 3A is a cross-sectional view taken along line 3A-3A of
FIG. 3;
[0022] FIG. 4 is a perspective view of a directional coupler sensor
system in accordance with one embodiment of the present
invention;
[0023] FIG. 4A is an enlarged front elevational view of a hair
clamping device for use in the sensor system of FIG. 4,
illustrating the clamping device in an open position to receive
hair in the device;
[0024] FIG. 4B is a view similar to FIG. 4A, illustrating the
clamping device in a closed position to clamp hair in the
device;
[0025] FIGS. 5A and 5B are side elevational views of a hair brush
incorporating the directional coupler sensor of the present
invention;
[0026] FIG. 6 is a graph illustrating the relationship between
output voltage of the directional coupler sensor and relative
humidity for various switches of hair;
[0027] FIG. 7 is a graph illustrating the relationship between
moisture content of hair by weight and relative humidity of hair;
and
[0028] FIG. 8 is a graph illustrating the relationship between
output voltage of the directional coupler sensor and pressure
applied to pack the hair.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] Referring now to the Figures, and to FIGS. 1 and 2A-2E in
particular, a directional coupler sensor 10 is shown in accordance
with the principles of the present invention. For the sake of
simplicity, the sensor 10 will be described herein in connection
with measuring the moisture content of hair. However, it will be
appreciated by those of ordinary skill in the art that the present
invention has use in a wide variety of applications and is
therefore not limited to the analysis of hair or the measurement of
moisture content in a substrate. Rather, the sensor 10 of the
present invention is readily adaptable to analyze a wide variety of
substrates and to measure different moisture related properties of
those substrates as will be readily appreciated by those of
ordinary skill in the art.
[0030] For example, in the measurement of the moisture content of a
substrate, the sensor 10 of the present invention operates under
the principle that as the moisture content of a substrate
increases, so does its effective relative electrical impedance. As
will be described in greater detail below, the sensor 10 is
designed to measure the relative impedance of a substrate, and from
that measurement, the moisture content of the substrate can be
determined. The moisture content value may be presented on a visual
display, indicated through a user-perceptible audible tone and/or
used as a control signal to control a function of a device.
[0031] As shown in FIGS. 1, 2A-2E, 3 and 3A, the sensor 10
incorporates a high frequency directional coupler 12 having a pair
of generally parallel strips 14a and 14b that define a coupling gap
16 therebetween. In one embodiment of the present invention, the
parallel strips 14a, 14b are supported on an FR4 printed circuit
board 18 (FIGS. 3 and 3A) having a ground plane 20 formed on a
lower surface of the board 18. In one embodiment of the present
invention, the height "h" of the PCB 18 is 0.062 in., each strip
14a, 14b has a width "w" of 0.15 in. and a length "l" of 0.350 in.,
and the coupling gap 16 has a gap distance "s" of 0.020 in. Of
course, it will be appreciated by those of ordinary skill in the
art that other dimensions of the PCB 18, strips 14a, 14b and gap 16
are possible as well depending on a particular application as will
be described in detail below.
[0032] A high frequency signal generator 22 is electrically coupled
to strip 14a and is operable to generate an electromagnetic field
across the coupling gap 16 that couples power to strip 14b with the
substrate placed across, i.e., generally normal to the longitudinal
axis of, the coupling gap 16 in a packed manner as will be
described in detail below. The signal generator 22 generates a
coupled power signal in the coupled strip 14b that has an amplitude
related to the impedance, and therefore the moisture content, of
the substrate placed across the coupling gap 16. The signal
generator 22 is phase locked to a crystal reference 24 (FIG. 2A) to
maintain frequency and therefore measurement accuracy, stability
and repeatability and has an adjustable power 26. The signal
generator 22 is preferably operable to generate signals in the VHF
to UHF frequency ranges, i.e., between about 30 MHz and about 3
GHz, although other frequency ranges are possible as well. In
accordance with one embodiment of the present invention, the signal
generator 22 may operate at about 1 GHz, such as at about 915 MHz,
since it is contemplated that the water content of a substrate may
be most accurately determined by its measured impedance in the near
GHz range.
[0033] In accordance with one aspect of the present invention, the
sensor 10 utilizes the reverse power coupling variation of the high
frequency directional coupler 12 to measure the change in the
impedance of the material placed across the coupling gap 16. As the
substrate is packed across the coupling gap 16, the directional
coupler 12 becomes mismatched, and this mismatch causes a monotonic
increase in the reverse power coupling of the directional coupler
12 as the impedance across the gap 16 is increased as the result of
increased moisture content of the material. The amplitude of the
reversed power in the reflected power leg 28 (FIGS. 1 and 2B) from
strip 14b is generally a direct measure of the impedance, and hence
the moisture content, of the substrate placed across the coupling
gap 16. As will be described in detail below, the moisture content
of the substrate, i.e., its water content by weight, can be
determined from the measured impedance of the sample.
[0034] Further referring to FIGS. 1 and 2A-2E, the forward power
signal from strip 14a is electrically coupled to one port of a
mixer 30 through a forward power leg 32 (FIGS. 1 and 2B) and an
attenuator 34. For example, the forward power signal may be
attenuated to about -10 dBm by the attenuator 34. The coupled power
signal from strip 14b is phase shifted by phase shifter 36 and is
electrically coupled to another port of the mixer 30 through the
reflected power leg 28. The mixer 30 may act as a coherent receiver
in that it is most responsive to coupled signals that are in phase
with the forward power signal. The phase shifter 36 assures the
proper phase coherence of the reflected power signal relative to
the forward power signal for the mixer 30 to produce the maximum
discernable mixer output. With the mixer forward power set to the
appropriate level through the adjustable power 26, the output of
the mixer 30 monotonically increases with an increase in the
reflected coupled power. The mixer 30 demodulates or reduces to DC
base band the value of the coupled power though the directional
coupler 12. The DC output of the mixer 30 is filtered and amplified
by amplifier 38 to produce a measurable output voltage that is
related to the moisture content of the substrate placed across the
gap 16. The amplifier 38 includes an adjustable gain 40 and an
adjustable DC offset 42.
[0035] Referring now to FIGS. 4, 4A and 4B, use of the sensor 10 to
determine the moisture content of hair will now be described in
connection with a hair moisture sensor system 44. Hair moisture
sensor system 44 may be used by a professional salon, for example,
to quickly, accurately and reliably indicate to a stylist when the
moisture content of a customer's hair is in the range of
approximately 30-40% by weight so that the optimum styling results
may then be achieved.
[0036] As shown in FIGS. 4A and 4B, a hair clamping device 46 is
provided having pivoted jaws 48 and 50 that each terminate in a
handle 52 that may be easily grasped and manipulated by the
stylist. The jaws 48 and 50 may be biased to an open position as
shown in FIG. 4A so that a bundle of hair 54 is readily received
between the jaws 48, 50 and is oriented with the hair fibers 54
extending across, i.e., generally normal to the longitudinal axis
of, the coupling gap 16 of the directional coupler 12 which is
supported by jaw 50. As shown in FIG. 8, it has been determined
that the packing pressure of C 5 the hair 54 across the coupling
gap 16 is important to ensure reliability in the moisture content
measurement. With low packing density below about three (3) lbs.,
i.e., a packing density in the pressure region 56, the output
voltage signal of the mixer 30 may be unstable due to insufficient
packing density of the hair fibers 54 across the coupling gap 16.
At higher packing pressures above about seven (7) lbs., i.e., a
packing density in the pressure region 58, the output voltage
signal of the mixer 30 begins to fluctuate as the hair fibers 54
will exhibit the result of difference in packing density across the
coupling gap 16. At these higher pressures, excess moisture is also
quickly expelled resulting in unreliable lower readings. It has
been determined that packing pressures in the range of about three
(3) lbs. to about six (6) lbs., i.e., a packing pressure in the
pressure region 60, provides an output voltage signal from the
mixer 30 that is stable to produce reliable and repeatable
measurements of the moisture content.
[0037] In accordance with another aspect of the present invention,
as shown in FIGS. 1, 2D, 4A and 4B, a pressure sensor 62
incorporating a film pressure transducer 64, is supported by the
jaw 48 in juxtaposition to the directional coupler sensor 12. The
pressure transducer 64 is operable to generate an output voltage
signal that varies with the packing pressure applied to the hair 54
placed across the coupling gap 16. As shown in FIGS. 1 and 2D, the
output voltage signal from the pressure transducer 64 is amplified
by amplifier 66 having an adjustable gain 68 and DC offset 70, and
that amplified output voltage signal is either provided directly at
the output of the pressure sensor 62 through jumper 72, or it is
applied as an input to a comparator 74 through jumper 76. A trigger
voltage corresponding to a desired trigger pressure is set as a
reference voltage 77 to the comparator 74. The measurement of the
moisture content is triggered upon the crossing of the pre-set
pressure threshold 77. This ensures that the desired compactness of
the hair fibers 54 placed across the coupling gap 16 is achieved to
obtain accurate, reliable and repeatable results. It will be
understood by those of ordinary skill in the art that packing
consistency can be achieved by a mechanical system (not shown) as
well without departing from the spirit and scope of the present
invention.
[0038] With reference to FIGS. 1 and 4, the measured signal from
the sensor 10, and the trigger signal or pressure signal from the
pressure sensor 62, are electrically coupled through a cable 78 to
a processing system 80, such as a conventional PC or laptop
computer. The processing system 80 is operable to convert the
measurement signal generated by the sensor 10 into a moisture
content value that may be presented on the display 82 of the system
80. As described in detail above, the measurement signal is
triggered in response to the trigger signal generated by the
pressure sensor 62. One or multiple measurements signals may be
taken in response to the trigger signal.
[0039] Referring now to FIGS. 6 and 7, the amplified output voltage
of the sensor 10 is calibrated by first subjecting multiple
switches of hair to a known moisture content via the use of
relative humidity. The sensor 10 is then used to generate a
measurement signal for each switch of hair at the various relative
humidities, as shown in FIG. 6. Since hair exhibits a generally
linear relationship between moisture content by weight and relative
humidity as shown in FIG. 7, the processing system 80 is operable
to convert the amplified output voltage of the sensor 10 into a
value representing the moisture content by weight of the hair using
a look-up table or algorithm. Since the water absorption capability
of damaged hair and healthy hair will differ, the sensor 10 of the
present invention may be used to provide a signal that is generally
related to the health of the hair. Generally, the health of hair is
characterized by such factors as smoothness, shine, absence of
frigility, absence of fissuring and absence of cuticular breakdown.
As each of these factors is directly or indirectly related to the
moisture content of the hair, the sensor 10 of the present
invention is able to provide an accurate and reliable indication of
the health of measured in vivo or in vitro hair.
[0040] The sensor 10 of the present invention provides a consumer
friendly self-assessment tool that permits a consumer to
periodically measure the general health of the consumer's hair.
Based on these measurements, the consumer is able to take
corrective actions as necessary which tend to improve the health of
the consumer's hair. These actions may include changing hair care
products, changing hair styling techniques, or both, so that the
general health of the consumer's hair can be consistently monitored
and improved. The sensor 10 also provides a useful monitoring tool
to hair stylists and hair technicians as well.
[0041] In accordance with another aspect of the present invention,
as shown in FIGS. 5A and 5B, the sensor 10 is incorporated into a
hair care product, such as a brush 84, used for grooming hair. The
brush 84 includes an elongated body portion 86 terminating in a
handle 88. Bristles 90 extend in a conventional manner from the
body portion 86 of the brush 84 to enable grooming of the hair. In
accordance with the principles of the present invention, as shown
in FIG. 3, the signal generator 22, mixer 30, voltage regulator 92
(FIG. 2E) and electronics of the pressure sensor 62 are all
integrated onto the PCB board 18 which is supported on a fixed base
94 of a hair clamping device 96 (FIGS. 5A and 5B). The fixed base
94 positions the directional coupler 12 near the bristles 90 so
that measurements are easily taken while the hair is being brushed.
The hair clamping device 96 includes a spring biased clamp member
98 that positions the pressure transducer 64 in juxtaposition to
the directional coupler 12. A lever 100 is operatively connected to
the movable clamp member 98 to enable a user to clamp hair across
the coupling gap 16 when a sensor measurement is desired by moving
the clamp member 98 toward the fixed base 94 as shown in FIG. 5B.
The hair brush 84 may include LED's, and/or produce an audible
signal, to provide an indication to the user about the moisture
condition, health or other condition of the hair based on the
sensor measurement. While not shown, in will be appreciated that
the sensor 10 of the present invention may be incorporated into
other hair care products as well, such as a comb, curling iron, or
similar hair care product that preferably engages the user's hair
during grooming to provide a measurement of the moisture content,
health or other status of the hair based on the sensor
measurement.
[0042] The directional coupler sensor 10 of the present invention
is well suited to measure the moisture content, health or other
condition of hair since it possesses sensitivity to variations in
impedance in close proximity, such as about 0.1 in., to the
surfaces of the strips 14a and 14b. The height of this effective
measurement probing depth from the surfaces of the strips 14a, 14b
is a function of the electromagnetic field that couples the strips
14a and 14b. The height of the measurement probing depth may be
changed for a particular application by changing the height of the
PCB 18, the dielectric constant of the PCB 18, the dimensions of
the strips 14a, 14b, the coupling gap distance "s", and/or the
power supplied by the signal generator 22. By varying any or all of
these parameters, the height of the coupling field can be altered
to thereby change the effective measurement probing depth.
[0043] It is contemplated that sensor 10 may comprise multiple
directional couplers 12 electrically coupled to at least one signal
generator 22 to measure the respective moisture content of multiple
substrates in accordance with the principles described in detail
above. It is further contemplated that at least two of the multiple
directional couplers 12 may have different effective measurement
probing depths by varying one or more of the parameters described
in detail above.
[0044] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention.
[0045] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
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