U.S. patent application number 11/312911 was filed with the patent office on 2007-06-21 for automatic microfluidic fragrance dispenser.
Invention is credited to Zhiyu Hu.
Application Number | 20070138326 11/312911 |
Document ID | / |
Family ID | 38172347 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070138326 |
Kind Code |
A1 |
Hu; Zhiyu |
June 21, 2007 |
Automatic microfluidic fragrance dispenser
Abstract
A method and apparatus for dispensing fragrance into the air in
the vicinity of the user comprises a liquid reservoir and a
solid-state microfluidic controller actuated by a solid-state
switching device. The microfluidic device is designed to vaporize
or pump the fragrant material into the air and thereby release a
scent under the manipulation of an electrical circuit, which is
preferably battery powered. The entire device consisting of fluid
reservoir, pump or valve, power supply, and electronic controls, is
preferably small enough to be conveniently attached to clothing or
worn by the user. The device may further be contained in a
substantially decorative housing and worn like jewelry. The device
may be pre-programmed to dispense automatically according to a
preset cycle, or it may be adjustable or programmable to some
degree by the user.
Inventors: |
Hu; Zhiyu; (Knoxville,
TN) |
Correspondence
Address: |
ROBERT J. LAUF
998 W. OUTER DRIVE
OAK RIDGE
TN
37830
US
|
Family ID: |
38172347 |
Appl. No.: |
11/312911 |
Filed: |
December 20, 2005 |
Current U.S.
Class: |
239/690 |
Current CPC
Class: |
A61L 9/035 20130101;
A01M 1/2077 20130101; A01M 1/2044 20130101; A01M 1/2038 20130101;
A61L 9/145 20130101 |
Class at
Publication: |
239/690 |
International
Class: |
F23D 11/32 20060101
F23D011/32 |
Claims
1. An apparatus for dispensing fragrances comprising: a fluid
reservoir containing a selected fragrance; a solid-state
microfluidic circuit to control the release of said fragrance from
said reservoir; a solid state switching device configured to
actuate said microfluidic circuit according to a selected program;
and, a power supply configured to provide electric power to operate
said switching device and said microfluidic circuit.
2. The apparatus of claim 1 wherein said selected program comprises
a preset schedule of actuations at selected intervals of time.
3. The apparatus of claim 1 wherein at least one parameter of said
selected program is adjustable by the user.
4. The apparatus of claim 1 wherein said solid state switching
device comprises a device selected from the group consisting of:
application specific integrated circuits and field-programmable
gate arrays.
5. The apparatus of claim 1 wherein said microfluidic circuit
comprises a device selected from the group consisting of: piston
pumps, electrokinetic pumps, peristaltic pumps, dielectric pumps,
valves, check valves, nozzles, heaters, and micromachined fluid
channels.
6. The apparatus of claim 1 wherein said power supply comprises a
device selected from the group consisting of: batteries and
photovoltaic devices.
7. The apparatus of claim 1 wherein said fragrance comprises a
substance selected from the group consisting of: essential oils,
natural plant extracts, natural animal extracts, synthetic esters,
pheromones, and insect repellents.
8. The apparatus of claim 1 wherein said fluid reservoir comprises
a plurality of individual chambers, each containing a different
selected fragrance, and said microfluidic circuit is adapted to
selectably withdraw fluid from said individual chambers.
9. The apparatus of claim 8 wherein said microfluidic circuit is
adapted to withdraw fluids from at least two of said individual
chambers and blend said fluids in a selected ratio whereby a
selected fragrance blend is dispensed.
10. The apparatus of claim 1 further comprising a decorative
housing adapted to allow said apparatus to be worn by the user.
11. A method of dispensing fragrances comprising the steps of:
providing a fluid reservoir containing a selected fragrance;
providing a solid-state microfluidic circuit configured to dispense
said fragrance from said reservoir at a selected rate; providing a
solid-state switching device configured to actuate said
microfluidic circuit for a selected duration at selected times;
and, providing a power supply sufficient to operate said switching
device and said microfluidic circuit, whereby said fragrance may be
withdrawn from said reservoir at a selected rate for vaporization
into the surrounding air.
12. The method of claim 11 wherein said solid state switching
device comprises a device selected from the group consisting of:
application specific integrated circuits and field-programmable
gate arrays.
13. The method of claim 11 wherein said microfluidic circuit
comprises a device selected from the group consisting of: piston
pumps, electrokinetic pumps, peristaltic pumps, dielectric pumps,
valves, check valves, nozzles, heaters, and micromachined fluid
channels.
14. The method of claim 11 wherein said power supply comprises a
device selected from the group consisting of: batteries and
photovoltaic devices.
15. The method of claim 11 wherein said fragrance comprises a
substance selected from the group consisting of: essential oils,
natural plant extracts, natural animal extracts, synthetic esters,
pheromones, and insect repellents
16. The method of claim 11 wherein said fluid reservoir containing
said fragrance is pressurized to an internal pressure greater than
atmospheric and said microfluidic device contains a valve for
controllably releasing said pressurized fluid.
17. A method of dispensing fragrances comprising the steps of:
providing a fluid reservoir containing a selected fragrance, said
fragrance having aromatherapeutic attributes; providing a
solid-state microfluidic circuit configured to dispense said
fragrance from said reservoir at a selected rate; providing a
solid-state switching device configured to actuate said
microfluidic circuit for a selected duration at selected times;
and, providing a power supply sufficient to operate said switching
device and said microfluidic circuit, whereby said fragrance may be
withdrawn from said reservoir at a selected rate for vaporization
into the surrounding air.
18. The method of claim 17 wherein said aromatherapeutic fragrance
comprises an essential oil selected from the group consisting of:
angelica root, anise, Peru balsam, basil, bay, bay laurel, beeswax,
bergamot, mint bergamot, bois-de-rose, boronia, cajeput, cardamom,
carrot seed, cedarwood, chamomile, cinnamon, citronella, clary
sage, clove bud, coriander, cypress, dill, elemi, eucalyptus,
fennel, fir needle, frankincense, galbanum, geranium, rose
geranium, ginger, grapefruit, helichrysum, hyssop, immortelle,
jasmine, juniper berry, kanuka, lavender, lavendin, lemon, lemon
grass, lime, linden blossom, mandarin, manuka, marjoram, may chang,
myrrh, myrtle, neroli, niaouli, nutmeg, oakmoss, olibanum, bitter
orange, sweet orange, oregano, palmarosa, parsley, patchouli, black
pepper, peppermint, pettigrain, Scotch pine, ravensera, rose,
rosemary, rosewood, sandalwood, spearmint, spikenard, spruce,
tagetes, tangerine, tea tree, thyme, tobacco, tuberose, vanilla,
vetiver, violet leaf, yarrow, and ylang-ylang.
19. The method of claim 17 wherein said aromatherapeutic fragrance
further contains a carrier oil selected from the group consisting
of: sweet almond, apricot kernel, avocado, borage, cocoa butter,
evening primrose, grapeseed, hazelnut, jojoba, kukui, macadamia
nut, olive, peanut, pecan, rose hip, sesame, shea butter, and
sunflower.
20. The method of claim 17 wherein said aromatherapeutic fragrance
further contains a solvent selected from the group consisting of:
water, alcohols, and ketones.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention pertains to apparatus and methods for
dispensing fragrances and more particularly to wearable
microfluidic dispensers for releasing controlled amounts of
fragrance compounds at controlled intervals.
[0003] 2. Description of Related Art
[0004] Fragrances and perfumes can be applied onto skin, clothes or
other objects for releasing scent and odor. There are two basic
techniques for perfume application. One is to directly apply
perfume/cologne liquid or concentrate onto the targeted subject.
Another is to pump through a dispenser that vaporizes the perfume
via a fan or atomizes the liquid perfume into many very small mist
droplets by compressed air flow. These application methods have
been around for centuries. The main disadvantages of these methods
include: 1. The scent concentration generally is too strong right
after the application then it becomes weaker over the time. The
user has no control of scent concentration level over time. 2. Many
perfume/cologne are designed in such a way once they are applied
onto skin the user's body heat acts like a vaporizer or scent
dispenser to promote the circulation of odor. The problem is that
same perfume/cologne might react differently on the people's skins,
altering the scent and, in some cases, causing irritation or
allergic reactions. 3. To change the scent from one perfume to
another, one needs to remove the first and apply the new perfume.
This might be impractical because of the time constraints or
restrictions of social circumstances. 4. Chemicals such as alcohol
or aldehyde often are preferred choice of solvent and they are also
the odor carrier of perfume as they evaporate. But they could also
cause skin irritation and other problems. For example, the odor of
these chemicals might interfere with the scent of perfume.
[0005] As used herein, the term "fragrance" includes any natural or
synthetic volatile compounds, solutions, or mixtures that have some
intended olfactory effect in humans or animals. The effect may be
conscious, as in the case of perfume or cologne, or subconscious,
as in the case of pheromones. The compounds may be relatively
undetectable by the user yet have desired masking effects against
the olfactory senses of animals. Examples include so-called insect
repellents as well as scent masking agents for hunters. A further
class of fragrances for which the present invention may be used
includes various scented agents to which medicinal effects have
been attributed, i.e., so-called "aromatherapy" agents.
[0006] Perfume is the term applied to a strong alcoholic solution
of odorants, as opposed to weaker solvents such as toilet waters
and eaux de cologne. Colognes, eaux de toilette, eaux de parfum,
and other "dilute perfumes" have a concentrate content of 3% to 8%
prepared in a 75.degree. to 90.degree. alcohol solution. They
contain perfume oil, water (the presence of water generally
increases the persistence of odors on the skin), and alcohol.
Perfumes generally cover a range of 10% to 35% concentrate with an
alcoholic strength between 85.degree. and 95.degree.. A higher
perfume concentration does not mean higher strength and tenacity;
too high a concentration causes the fragrance to be dull and
non-diffusing. It has been known for some time that perfumes that
had lasting success had similar or identical evaporation
behaviors.
[0007] Natural odorants in perfumery are generally classified into
seven categories: 1. Concrete Oils or "natural flower oils":
Flowers, leaves, and roots are subjected to extraction by
hydrocarbon solvents, which dissolve the waxes containing the
odorous principles from the flowers. The concrete of the flowers
has the appearance of solid wax and is insoluble in water and
alcohol. It is possible to dissolve it by mixing in 95.degree.
alcohol for about a month. Odorous products of the flower are then
obtained. 2. Absolute Oils: Obtained by extracting concretes with
alcohol, then eliminating the alcohol at reduced pressure. The
product obtained is soluble in alcohol and has the consistency of
honey. 3. Essential Oils: Derived from a distillation process
applied to flowers, leaves, stalks, herbs, roots, and certain
fruits. They are the most widely used of all natural perfumery
materials. Some oxidation-prone essential oils are treated on
production site with traces of antioxidants. 4. Essential Oils
Obtained by Expression: Citrus fruits yield essential oil by
squeezing the peels. 5. Isolates etc. from Essential Oils: These
products are midway between natural and synthetic products. 6.
Natural Odorants as Tinctures: Some natural products are used in
the form of tinctures by mixing in 95.degree. alcohol for a period
of time. Examples include animal musk, ambergris, civet, castoreum,
root, and oakmoss. 7. Balsams and Resins: Resin materials found on
trees and plants are extracted with different solvents.
[0008] Synthetic products used in perfumery include the following:
1. Aldehydes, esters, ethers, ketones, and lactones. 2. Methyl
heptin carbonate (MHC), a potent alkyne carbonate used with
restraint and discrimination, has a fresh, penetrating odor used as
an odorant of green, violet-leaf fragrances, when used in 5%
dilution gives excellent, long-lasting effects in violet gardenia,
freesia, and other perfumes. 3. Phenylacetaldehyde gives a pungent
green odor used as constituent of spring flower perfumes, but is
somewhat unstable. 4. Dimethyl acetal gives a characteristically
green odor suggesting fresh wet foliage, useful in woody, mossy,
and certain floral types, and is probably the most frequently used
acetal in perfumery. 5. Ethyl methyl phenyl glycidate is the chief
component of artificial strawberry compounds. 6. Acetates are most
profusely used of all the esters; the most important class of
synthetic odorants produced is the aliphatic aldehydes.
[0009] Several types of dispensers suitable for fragrances have
been known for many years. These include the familiar pump-type
spray bottles and the gas-powered or "aerosol" cans. Both of these
applicators dispense a stream or mist of liquid droplets on demand.
A pump-type dispenser may be refillable or the pump head may be
interchangeable among different reservoir bottles. Aerosol cans are
most often disposable once the contents are exhausted. Other
devices include a container with a porous wick that generally
resembles a felt-tip pen and may be uncapped and dabbed on the
user's skin at desired intervals. Yet another approach for
controlled release of a fragrance or insect repellent involves an
adhesive patch to be worn by the user, the patch having a
multilayer structure intended to release a scent at a controlled
rate (see Fischel-Ghodsian, U.S. Pat. No. 5,071,704).
[0010] An article of jewelry containing a refillable fragrance
dispenser is disclosed by Chin, et al. in U.S. Pat. No. 4,785,642.
The dispenser consists of a capped, cylindrical vial filled with an
absorbent material and having a small hole in the cap, through
which the fragrance escapes by natural evaporation.
[0011] Stationary devices that dispense fragrance into the air are
broadly referred to as "room fresheners". These may be
substantially passive devices in which the desired fragrance is
released by evaporation from a porous wick (see Compton et al.,
U.S. Pat. No. 4,323,193) or from a hydrogel (see Lanzet, U.S. Pat.
No. 2,927,055; Graiver et al., U.S. Pat. No. 4,891,389). The
evaporation rate may be controlled by manually opening or closing
the device, by raising the wick, and so on. These devices may
alternatively contain fans, heating elements, etc. to enhance or
control the release of the selected fragrance.
[0012] A further class of fragrance dispensing devices includes
systems for releasing fragrances, detergents, etc. into a lavatory.
Various means have been described for controlling the release of
these generally liquid substances to minimize waste. Such means
include installing infrared detectors to actuate the device each
time a user approaches or leaves (see, for example, Shieh, U.S.
Pat. No. 5,377,363), electrical switches or hydraulic valves to
actuate the device when the lavatory is flushed, and other means
(see, for example, Stone, U.S. Pat. No. 6,694,534).
OBJECTS AND ADVANTAGES
[0013] Objects of the present invention include the following:
providing an apparatus and method for releasing small, controlled
amounts of volatile compounds; providing a wearable fragrance
dispenser that releases one or more selected fragrances in the
vicinity of the wearer at selected rates or selected intervals;
providing a wearable fragrance dispenser that also serves the
aesthetic function of jewelry; providing a fragrance dispenser that
may be concealed on the person; providing a means for dispensing
selected fragrance compounds near the user without depositing the
fragrance directly on the skin or clothing; and, providing a means
of dispensing controlled doses of aromatherapy agents. These and
other objects and advantages of the invention will become apparent
from consideration of the following specification, read in
conjunction with the drawings.
SUMMARY OF THE INVENTION
[0014] According to one aspect of the invention, an apparatus for
dispensing fragrances comprises: a fluid reservoir containing a
selected fragrance; a solid-state microfluidic circuit to control
the release of the fragrance from the reservoir; a solid state
switching device configured to actuate the microfluidic circuit
according to a selected program; and, a power supply configured to
provide electric power to operate the switching device and the
microfluidic circuit.
[0015] According to another aspect of the invention, a method of
dispensing fragrances comprises the steps of: providing a fluid
reservoir containing a selected fragrance; providing a solid-state
microfluidic circuit configured to dispense the fragrance from said
reservoir at a selected rate; providing a solid-state switching
device configured to actuate the microfluidic circuit for a
selected duration at selected times; and, providing a power supply
sufficient to operate the switching device and the microfluidic
circuit, whereby the fragrance may be withdrawn from the reservoir
for vaporization into the surrounding air at a selected rate.
[0016] According to another aspect of the invention, a method of
dispensing fragrances comprises the steps of: providing a fluid
reservoir containing a selected fragrance, the fragrance having
aromatherapeutic attributes; providing a solid-state microfluidic
circuit configured to dispense the fragrance from the reservoir at
a selected rate; providing a solid-state switching device
configured to actuate the microfluidic circuit for a selected
duration at selected times; and, providing a power supply
sufficient to operate the switching device and the microfluidic
circuit, whereby the fragrance may be withdrawn from the reservoir
at a selected rate for vaporization into the surrounding air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The drawings accompanying and forming part of this
specification are included to depict certain aspects of the
invention. A clearer conception of the invention, and of the
components and operation of systems provided with the invention,
will become more readily apparent by referring to the exemplary,
and therefore non-limiting embodiments illustrated in the drawing
figures, wherein like numerals (if they occur in more than one
view) designate the same elements. The features in the drawings are
not necessarily drawn to scale.
[0018] FIG. 1 is a schematic diagram of one embodiment of the
present invention, in which a solid-state microfluidic device
dispenses a fragrance from a fluid reservoir.
[0019] FIG. 2 is a schematic diagram of an embodiment of the
invention in which the components of a fragrance-dispensing device
are contained within a protective housing.
[0020] FIG. 3 is a schematic diagram of an embodiment of the
invention having a plurality of fluid reservoirs, each containing a
separate fragrance.
[0021] FIG. 4 is a schematic diagram of an embodiment of the
invention adapted to be worn as a pendant.
DETAILED DESCRIPTION OF THE INVENTION
[0022] In its most general form, the invention contains a fluid
reservoir holding a desired fragrance in liquid form. The liquid
may include such ingredients as essential oils, natural or
synthetic odor compounds, esters, phenols, etc., along with
solvents or diluents such as water, alcohol, etc. The fluid
reservoir is connected to a microfluidic control element including
one or more micromachined channels through which the fluid may be
pumped in order to release the scent. A conventional solid-state
controller is provided to actuate the microfluidic control element
at selected intervals in order to maintain the desired level of
fragrance release. A battery or other conventional power source
(such as a photovoltaic cell) is provided to drive the various
elements.
[0023] The foregoing components are preferably combined into a
low-cost, substantially self-contained device or cartridge that may
be disposable when the liquid is exhausted. A decorative housing
unit may be provided to carry the cartridge, thereby doubling as an
item of jewelry such as a necklace, brooch, hair clip, or the like.
In this embodiment, the battery and/or solid-state controller may
be contained in the housing unit, thereby minimizing the cost of
the disposable cartridge element, and in that case the housing unit
will contain electrodes that engage corresponding contacts on the
cartridge. Various conventional means such as keyways, etc., may be
used to ensure that the electrodes and contacts maintain the
necessary alignment to engage properly.
[0024] Some exemplary categories of fluid dispensing technology
include: Pin transfer, needle dispensing, jetting, and spraying.
Pin transfer uses a pin that is dipped into a reservoir of fluid.
The fluid is transferred to the part by touching the pin to surface
of the part. Needle dispensing is one of the more common methods
used in automated fluid dispensing. Material is extruded through a
needle that is held close to the surface of a part. As the needle
is pulled away, the fluid is held to the board by gravity and
surface tension. A variety of devices can be used to extrude the
material through the needle: auger pumps, pneumatic pumps, or
piston pumps.
[0025] Needle dispensing devices may include valves to control the
flow of very low viscosity fluids. Material viscosity from 1 cp
(e.g., water) to over 1,000,000 cp (e.g., thick grease) can be
dispensed with needles.
[0026] Jet dispensing energizes a specific quantity of fluid such
that the kinetic energy of the fluid is used to break the fluid
stream from the nozzle. Viscosities of 1 cp (e.g., water) to over
100,000 cp (e.g., surface mount adhesives) can be jetted with
various mechanisms. Complex fluid rheology is an important factor
in the suitability of a fluid for jetting. Picoliter volumes of low
viscosity materials are widely used in printing technology;
however, fluids used in these applications are generally limited to
specially formulated inks. Jetting of materials likely to be used
for MEMs assemblies, such as adhesives, find a practical limitation
of approximately 3 nanoliters and larger. Diameters of
approximately 250 .mu.m are possible. Many of the limitations of
solid content and filler size of needle dispensing apply to
jetting.
[0027] Jetting fluids can provide some unique advantages. The
energy for breaking the fluid from the nozzle comes from the
kinetic energy of the fluid. Jetting is less sensitive to the gap
between the nozzle and the part. The fluid stream from a jet can be
as small as 100 .mu.m in diameter, allowing fluid to be deposited
in areas that it is not possible to place a needle.
[0028] Dot Dispensing: Large deposits of fluid can be made with
relative ease, so the discussion here will focus on the practical
lower limits available commercially. With pin transfer, fluid
deposits of <1 nanoliter and 100 .mu.m in diameter are possible
with many adhesives. The stability of the processes are difficult
to control since the amount of fluid deposited can vary as fluid
characteristics change. The process requires open containers of
fluid.
EXAMPLE
[0029] The basic elements of the invention are shown schematically
at 10 in FIG. 1. Fragrant liquid 11 is contained within reservoir
12. A microfluidic device 13 receives liquid 11 from reservoir 12.
A control circuit 14 receives power from power source 15, which may
be a battery, photocell, or other suitable device, and applies an
actuating signal to microfluidic device 13 through conductors 17.
The actuating signal causes microfluidic device 13 to dispense a
small droplet 16 of the fragrant liquid.
[0030] As shown in FIG. 1, it is preferable that the droplet 16 is
dispensed to the surface of the device for evaporation, rather than
forcefully ejected as would be the case in a typical ink-jet
printer head. An ink-jet printer head may consume as much as 12 W
of power. Simple dispensing, rather than forceful ejection,
requires significantly less energy and is therefore more suited to
a small, battery-powered device.
[0031] Skilled artisans may construct the inventive device by
routine engineering practices using a number of suitable
components, including the following: Suzuki et al. (Sensors and
Actuators B 2002, 86, pp. 242-250) have described a micropump
system, which could pump liquid at a rate of 2 nl per second with a
1.2 V bias and 0.1 mA current or 0.12 mW. A small fluidic reservoir
could easily be attached to the micropump using conventional
adhesives. Tsai et al. (J. of Microelectromechanical Systems 2002,
11[6], pp. 665-671) have described a thermal-bubble
micronozzle-diffuser pump which is able to pump a very large volume
of liquid at a rate of 4.about.5 gl/min when the driving pulse is
250.about.400 Hz and duty cycle of 5.about.10% with a power
consumption of about 0.5 W. When the system operates at 3 Hz pulse
excitation frequency and the duty cycle of 5%, the average power
consumption is only 50 mW. Commercially available "coin" lithium
batteries (e.g., BRxxxx and CRxxxx series, Panasonic Corp.) have a
power capacity up to 1000 mAh with a weight of a few grams that
could provide enough power to operate the micropump continuously
for more than one and half years.
[0032] From the foregoing description it will be apparent that the
invention overcomes a fundamental limitation of prior fragrance
dispensing approaches, viz., that a particular fragrance might
include several components with differing rates of evaporation. A
dispenser that relies on evaporation from a small orifice (as
disclosed in U.S. Pat. No. 4,785,642) or one that relies on
evaporation from a gel body (as described in U.S. Pat. No.
2,927,055) will invariably display some effect of differential
evaporation. The composition of the fragrant material remaining in
the reservoir will therefore tend to change somewhat with time and
the perceived fragrance will change with it. In the inventive
device, a very small volume of liquid is withdrawn from the
reservoir and completely converted to vapor before a second volume
of fluid is withdrawn. Thus, the bulk composition of the liquid
remaining in the reservoir does not change with time and the
fragrance is therefore more uniform.
[0033] Various approaches exist for manufacturing microfluidic
devices that may be used to carry out Applicant's invention.
Channels of the appropriate size may be etched into glass or
silicon and various strategies may be used to pump the fluid,
including local heating, electroosmotic effects, piezoelectric
actuation, etc. Familiar examples of practical applications of
microfluidic devices include ink-jet printers and various
small-scale chemical reaction devices (see, for example, Ramsey,
U.S. Pat. No. 5,858,195). A general summary of microfluidic
technology and devices is given by Hansen, et al. (Current Opinion
in Structural Biology 2003, 13, pp. 538-544), and Barry, et al.
(Journal of Nanobiotechnology 2004, 2, pp. 2-6), and Erickson et
al. (Analytica Chimica Acta 2004, 5071, pp. 11-26), and Ziaie et
al. (Advanced Drug Delivery Reviews 2004, 56[2], pp. 145-172) and
Malek et al. (Microelectronics Journal 2004, 35[2], pp. 131-143),
and Beebe et al. (Annual Review of Biomedical Engineering 2002, 4,
pp. 261-286) and Darhuber (Annual Review of Fluid Mechanics 2005,
37, pp. 425455). A piston-type pump made by MEMS techniques is
disclosed by Galambos, et al. in U.S. Pat. No. 6,886,916. A
microfabricated electrokinetic pump is disclosed by Corbin, et al.
in U.S. Pat. No. 6,881,039. A pump and passive check valve is
disclosed by Dai, et al. in U.S. Pat. No. 6,874,999. A method of
building peristaltic micropumps using polydimethylsiloxane
multilayer soft lithography is described by Goulpeau, et al.
(Journal of Applied Physics 2005, 98, #044914). An electrokinetic
pump for pumping a liquid including a pumping body having a
plurality of narrow, short and straight pore apertures for
channeling the liquid through the body is described by Corbin, et
al. in U.S. Pat. No. 6,881,039; and by Kopf-Sill, et al. in U.S.
Pat. Nos. 6,524,790; 6,613,512; and 6,703,205. A method of building
a dielectric pump to move fluids which have two dissimilar
dielectric constants from an interface through microchannels is
described by Vacca in U.S. Pat. No. 6,949,176. An apparatus and
method for controlling the delivery of fluids and, in particular,
to the delivery of fluids to a receptor is described by Kane, et
al. in U.S. Pat. No. 6,109,717. Shawgo, et al. (Current Opinion in
Solid State & Materials Science 2002, 6[4], pp. 329-334)
described MEMS-based micropumps and their applications for drug
delivery. Any or all of the foregoing microfluidic devices and
methods may be suitable to use in implementing the present
invention.
[0034] As noted, the device preferably operates in a mode that
avoids the forceful ejection of droplets (in contrast to the
operation of an ink-jet printer, for example). Various elements may
therefore be provided to help convert the pumped fluid to vapor.
For example, a porous layer may be disposed on an outside surface
of the device; the microfluidic element may pump the fluid to this
porous layer, from which it will evaporate in a controlled manner.
Alternatively, a heating element may optionally be provided,
preferably as an integral part of the microfluidic device.
[0035] As discussed in the foregoing example, it is necessary to
provide a means for actuating the microfluidic device, preferably
for a selected duration at some selected time interval. This is
preferably done using a small integrated circuit that contains at
least a timing function and a switching function, and, preferably,
a memory function. Those skilled in the art will appreciate that
many conventional circuits will be suitable for this device, which
may be implemented as an application specific integrated circuit
(ASIC) or as a field-programmable gate array (FPGA) or similar
device and its associated software. The skilled artisan, by
applying routine engineering principles, may therefore select the
most appropriate control circuit 14 based on the choice of
microfluidic device 13, cost and performance objectives, power
consumption, and other considerations. For the control circuit 14,
appropriate time and drive signal could be provided by a
microcontroller such as MAXIM (Dallas Semiconductor, Dallas, Tex.)
DS80xx, DS87xx or DS89xx series. Some of these chips have a
built-in memory and can be programmed by users. Other examples of
suitable microcontrollers are Texas Instruments MSPxx series and
Motorola MC68xx series chips.
[0036] In order for the device to be small and simple to use, it is
generally preferred that the device has a single operating mode,
wherein once activated by the user the device simply releases
fragrance at regular intervals over a predefined time scale.
However, it will be appreciated that a more sophisticated device
can be constructed, whose operating parameters may be
user-programmed over some range. Such user programming may be as
simple as a small multiposition switch (e.g., low-medium-high) that
can select either greater or lesser duration of the individual
actuations or shorter or longer times between actuations. In a more
sophisticated design, a continuous user-programmable controller may
be used. This controller may further contain visual indicators such
as LED elements or an LCD display to indicate various operating
states. Alternatively, the device may be adapted to interact with a
base station (through a temporary electrical connection, wireless
data link, or the like) from which it may download a more
complicated operating profile.
[0037] In many instances it will be preferable to provide a means
such as a vent or check valve in order to allow air to enter the
reservoir 12 to compensate for the volume of fragrant liquid 11
being removed therefrom. A mechanical check valve and air passage
may be fabricated as one component on the microfluidic device 13 or
other conventional venting means may be employed. It will be
appreciated that in some instances it may be practical to
pressurize the reservoir 12 in which case the microfluidic device
13 may be simplified to employ a valve rather than an active
pumping mechanism.
EXAMPLE
[0038] The components indicated schematically in FIG. 1 may be
combined within a housing in order to provide a small,
self-contained, and relatively robust unit as shown schematically
in FIG. 2. An outer housing 21 is provided, which contains spring
mounted battery 15', control circuit 14, reservoir 12, and
fragrance 11. The solid-state fluidic device 13 is located under
reservoir 12 and is protected by a mesh 28, which serves to protect
the surface of the device from damage while allowing the vaporized
fragrance to escape. The mesh may further provide a decorative
function if desired.
EXAMPLE
[0039] The invention may also be adapted to dispense more than one
fragrance as shown generally at 30 in FIG. 3. Three separate
reservoirs 12' contain fluids 11', 11'', and 11'''. As shown in
FIG. 3, the device may be configured so that one multichannel solid
state microfluidic device 13' (driven by control circuit 14)
receives fluids from each of the reservoirs 12'. It will be
appreciated that the microfluidic device 13' may be controlled to
dispense individual fragrances 11', 11'', and 11''' selectively at
various times, to dispense them as separate droplets at the same
time, or to blend them in selected ratios and dispense droplets of
the resulting blended composition. The components may be contained
within housing 21 and protective mesh 28, as in the previous
example.
[0040] It will be apparent to those skilled in the art that this
embodiment may be implemented in many alternative configurations to
achieve substantially the same purpose. For example, one housing
unit may be configured to accept several dispensing cartridges 20,
each with its own microfluidic device 13. The cartridges may be
substantially self-contained, i.e., have individual power supply 15
and control circuit 14. Alternatively, the housing unit may contain
a single power supply 15 with electrical contacts to engage each of
the dispensing cartridges 20. The housing unit may further contain
a single microprocessor or switching device 14 with electrical
contacts to engage each of the microfluidic devices 13.
[0041] It will be further appreciated that although some exemplary
devices are shown with an on-board battery as a preferred power
source, any suitable power source may be used, including
photovoltaic cells, capacitive storage elements, and others. The
device may also be provided with a wire, cable, plug, or jack
arrangement in order to accept power from a larger external power
source. This may be useful, for example, in a device intended for
use in an automobile, wherein power may be supplied via a wire in
the auto's electrical system. Furthermore, the actuating signal
from control circuit 14 may be delivered to microfluidic device 13
via a hard-wired connection or via a wireless link using any
conventional wireless protocol.
[0042] It will be understood that in some instances the housing
unit is intended to be a permanent piece of fine or costume
jewelry, in which the wearer may replace the fragrance-dispensing
unit when it is used up, or to select a different fragrance. In
some cases, the housing unit may be worn for its decorative value
even when fragrance is not being dispensed. Furthermore, it will be
appreciated that the housing unit may provide a degree of
mechanical protection to the cartridge, particularly in the case
where the fluid reservoir is a small glass vial.
EXAMPLE
[0043] Illustrated schematically at 40 in FIG. 4 is an embodiment
of the invention in which fragrance dispenser 41 is adapted with a
chain 42, allowing it to be worn as a necklace. Similarly,
dispenser 41 may be adapted to be attached to, or integral with,
other personal items such as a pin, brooch, hair clip, wristwatch,
telephone handset, and so on.
[0044] In other instances, it may be desirable to make the housing
unit from very inexpensive materials so that the entire item is
disposable once the fragrance has been completely dispensed. The
housing unit may be provided with various conventional means for
attachment to the body or clothing of the user; these means can
include chains, hooks, pins, dips, and the like.
[0045] It will be further appreciated that in some applications the
entire unit may be designed to be fairly unobtrusive during use.
This might be advantageous, for example, in applications where the
device is dispensing pheromones, masking agents, insect repellents,
and the like. The unit may also be configured to fit in a user's
shirt pocket, to accommodate a larger fluid reservoir, larger
battery, etc., as might be desired for steady, long-term use by
outdoorsmen or the military.
[0046] In the aforedescribed situations the device is configured so
that it can be worn on the person. However, it will be appreciated
that because the device is generally compact and self-contained, it
may easily be deployed in other uses and locations. For example, it
may be placed in the ventilation system of an automobile, the air
outlet of an air conditioner, or other convenient location where
the user desires to have a controlled release of fragrance at
selected time intervals.
[0047] As noted earlier, perfumes, colognes, and other fragrant
products are typically mixtures or solutions of numerous chemical
compounds along with solvents and other additives. It will be
understood that the inventive device may be used for dispensing any
and all such mixtures, blends, solutions, or dispersions as are
familiar to those skilled in the art of fragrance production and
use. In the embodiment described in the foregoing examples, it will
be understood that when the apparatus includes several fluid
reservoirs, each of the individual fluids will, in turn, frequently
be a mixture or solution in its own right but it may, in some
cases, be a substantially pure component or concentrate.
[0048] The term aromatherapy describes a branch of holistic or
"traditional" medicine wherein various healing attributes are
associated with particular aromas. The practice of treating
physical or mental problems by the inhalation of specific aromas
has been carried out since ancient times and anecdotal evidence
among practitioners in the art identifies dozens of fragrances
purported to have some value in aromatherapy [see, for example V.
A. Worwood, The Complete Book of Essential Oils and Aromatherapy,
New World Library, 1991]. The materials typically used include
essential oils or extracts of various plants, flowers, herbs,
etc.
EXAMPLE
[0049] The inventive device may be used to dispense fragrances for
aromatherapy treatment. Individual fragrances or combinations of
fragrances may be selected by the user or prescribed by an
aromatherapy practitioner, who may also recommend frequency or
duration of treatment, etc. In this application, the inventive
device offers the advantage that the aromatherapeutic agent is
dispensed efficiently directly in the vicinity of the user, rather
than dispersed into the air to fill a room, for example.
[0050] Some examples of materials that have been offered for
aromatherapy include the following: angelica root, anise, Peru
balsam, basil, bay, bay laurel, beeswax, bergamot, mint bergamot,
bois-de-rose, boronia, cajeput, cardamom, carrot seed, cedarwood,
chamomile, cinnamon, citronella, clary sage, clove bud, coriander,
cypress, dill, elemi, eucalyptus, fennel, fir needle, frankincense,
galbanum, geranium, rose geranium, ginger, grapefruit, helichrysum,
hyssop, immortelle, jasmine, juniper berry, kanuka, lavender,
lavendin, lemon, lemon grass, lime, linden blossom, mandarin,
manuka, marjoram, may chang, myrrh, myrtle, neroli, niaouli,
nutmeg, oakmoss, olibanum, bitter orange, sweet orange, oregano,
palmarosa, parsley, patchouli, black pepper, peppermint,
pettigrain, Scotch pine, ravensera, rose, rosemary, rosewood,
sandalwood, spearmint, spikenard, spruce, tagetes, tangerine, tea
tree, thyme, tobacco, tuberose, vanilla, vetiver, violet leaf,
yarrow, and ylang-ylang. Many literature sources advise caution in
using these materials because many essential oils, in concentrated
form, can be toxic, irritating to the skin and mucous membranes, or
allergenic. The present invention affords a particular advantage in
the administration of such aromas because the method of dispensing
the material effectively precludes direct contact of the fluid with
the user's skin, eyes, or mucous membranes.
[0051] Aromatherapy products also frequently make use of solvents,
such as water or alcohol, as well as "carrier oils" such as sweet
almond, apricot kernel, avocado, borage, cocoa butter, evening
primrose, grapeseed, hazelnut, jojoba, kukui, macadamia nut, olive,
peanut, pecan, rose hip, sesame, shea butter, and sunflower.
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