U.S. patent application number 11/302179 was filed with the patent office on 2006-07-27 for methods and apparatus for sterilization of air and objects.
This patent application is currently assigned to Safe Haven, Inc.. Invention is credited to John Robert Berry, Lambert Darryl Berry.
Application Number | 20060165563 11/302179 |
Document ID | / |
Family ID | 33555493 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060165563 |
Kind Code |
A1 |
Berry; Lambert Darryl ; et
al. |
July 27, 2006 |
Methods and apparatus for sterilization of air and objects
Abstract
An air purification system that uses laser beams (40) to purify
air. A laser beam (42) is set to sweep across the interior of a box
(20) that is open at two ends to the flow of air. The laser beam
(42) is of sufficient strength to destroy or neutralize any dust
particles, pollen, pathogens, allergens, aor gasses that are
present in the flow of air through the box (20). An air baffle box
(80) is utilized at each end of the box with the air flow to
prevent the laser beam from escaping from the box.
Inventors: |
Berry; Lambert Darryl;
(Coronado, CA) ; Berry; John Robert; (Coronado,
CA) |
Correspondence
Address: |
GRAYBEAL, JACKSON, HALEY LLP
155 - 108TH AVENUE NE
SUITE 350
BELLEVUE
WA
98004-5901
US
|
Assignee: |
Safe Haven, Inc.
|
Family ID: |
33555493 |
Appl. No.: |
11/302179 |
Filed: |
December 12, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/US04/18772 |
Jun 14, 2004 |
|
|
|
11302179 |
Dec 12, 2005 |
|
|
|
10640477 |
Aug 11, 2003 |
|
|
|
PCT/US04/18772 |
Jun 14, 2004 |
|
|
|
60478231 |
Jun 12, 2003 |
|
|
|
Current U.S.
Class: |
422/121 |
Current CPC
Class: |
A61L 9/18 20130101; A61L
2/08 20130101 |
Class at
Publication: |
422/121 |
International
Class: |
A61L 9/18 20060101
A61L009/18 |
Claims
1. An air sterilization apparatus comprising: a body defining
chamber, at least two openings through which a volume of air may
travel, and an orifice; a source of collimated light energy adapted
for producing a plurality of discrete wavelength ranges operatively
directed to emit energy through the orifice and into the chamber;
and control means for modulating the total energy exposure of the
volume of air to the energy emission from the source of collimated
light energy.
2. The apparatus of claim 1 wherein the control means modulates the
velocity of the volume of air.
3. The apparatus of claim 1 wherein the control means modulates the
energy output of the source of collimated light energy.
4. The apparatus of claim 1 wherein the control means modulates the
dispersion characteristics of the emitted collimated light
energy.
5. The apparatus of claim 1 wherein the chamber comprises a
plurality of walls reflective of the collimated light energy, and
wherein at least some walls are one of planar, curved or
irregular.
6. The apparatus of claim 5 wherein at least some walls are movable
upon actuation.
7. The apparatus of claim 1 further comprising at least one light
baffle to prevent the unintentional escapement of collimated light
energy from the chamber.
8. The apparatus of claim 1 wherein the emitted light energy is
moved prior to entering the chamber.
9. The apparatus of claim 1 wherein the source of collimated light
energy is a laser.
10. The apparatus of claim 9 wherein the wavelength of light energy
is in the infrared spectrum.
11. The apparatus of claim 1, further comprising an enclosure
having a sealable interior environment and an environment control
system comprising a duct for communicating air from a first
location exposed to an exterior environment to a second location
exposed to an interior environment where the first opening of the
chamber is in communication with the exterior environment and the
second opening is in communication with the interior
environment
12. The apparatus of claim 1 further comprising a self-contained
power source for at least operation of the source of collimated
light energy
13. The apparatus of claim 12 wherein the power source is one of a
power generator, a battery, or a fuel cell.
14. An object sterilization apparatus comprising: a body defining
chamber, at least one opening through which an object may pass and
an orifice; a source of collimated light energy for producing at
least one discrete wavelength of energy operatively directed to
emit energy through the orifice and into the chamber; support means
for supporting the object once placed inside the enclosure; and
control means for modulating the total energy exposure of the
object to the energy emission from the source of collimated light
energy.
Description
CROSS-REFERENCE To RELATED APPLICATION
[0001] This is a continuation-in-part application that claims
benefit, under 35 USC .sctn.120, of co-pending International
Application PCT/US2004/018772 filed on 14 Jun. 2004, designating
the United States, which claims priority benefits under 35 USC
.sctn.119 to U.S. CIP Patent Applications No. 60/478,231, filed 12
Jun. 2003 and application Ser. No. 10/640,477 filed 11 Aug. 2003,
which applications are incorporated herein by reference.
BACKGROUND OF THE INVENTION
DESCRIPTION OF THE PRIOR ART
[0002] Sterilization of air and objects has been a common
requirement for environments having such requirements. For example,
both aspects are required for hospital surgical rooms. The practice
of dentistry usually does not require a sterile environment, but it
does require the use of sterile dental tools. The state of the art
discloses numerous devices and methods for achieving these
objectives. However, the inventions of the prior art are limited to
fixed installations, and are not considered portable nor adapted to
use for object sterilization regimens.
[0003] Recent world developments and increased concern over
biological weapons has created a need for field deployable
structures that provide a safe heaven from biological pathogens as
well as aerosols and suspended particulates. Conventional
technology is directed primarily towards filtration methods for
removing the above-noted micro objects. However, filtration has its
limits: cost, size, efficacy, etc.
[0004] Another environment that requires filtration in a sealable
environment are aircraft in general, and commercial pressurized
aircraft in particular. In this environment, a significant
percentage of the cabin and cockpit air is recycled. Biological
pathogens as well as aerosols and suspended particulates should be
removed or reduced in order to minimize the effects of these
micro-objects on passengers and professional staff. However, the
filtration units on most aircraft do not provide the optimal level
of filtration, and it is common to be exposed to undesirable
micro-objects, e.g., bacterial or viruses, from either interior
sources or exterior sources.
[0005] Object sterilization has been primarily limited to use of
heat and optionally pressure to sterilize objects, particularly for
use in surgical environments. The tools subject to such
sterilization fortunately are tolerant of the sterilization
environment, however, the sterilization environment limits the type
of tools that may be used for surgical procedures. As noted above,
the prior art with respect to laser sterilization has been
primarily directed to the sterilization of mediums within enclosed
vessels, as opposed to the sterilization of objects within the
vessel.
SUMMARY OF THE INVENTION
[0006] The invention is directed to methods and apparatus for
sterilization of air and objects using collimated light of
proscribed frequencies (wavelengths), energy densities and
durations. The methods broadly encompass directing at least one
beam, and in larger applications of embodiments of the invention
beams from multiple discrete sources, emitted from a laser or
equivalent source of non-ionizing collimated electromagnetic
radiation towards a target volume and irradiating the volume for a
sufficient period. The duration of radiation exposure depends, in
part, upon the residency period of objects within the volume, the
intensity and/or energy density of the radiation, the frequency or
frequencies of the radiation, and other variables that will be
described in more detail below.
[0007] In one series of embodiments, the invention is optimized to
affect relatively small objects suspended in an air stream.
Throughout this patent, this embodiment is referenced as an air
sterilization apparatus. These relatively small objects comprise
microbes, viruses, particulates, and other micro-objects. The air
sterilization apparatus comprises a chamber having an inlet end and
an outlet end wherein air is introduced into the chamber at the
inlet end and is permitted to exit therefrom through the outlet
end. The chamber also defines a substantially transparent orifice
through which at least one beam of collimated electromagnetic
radiation can pass into the chamber. The orifice may be an opening
or may be an opening fitted with a material substantially
transparent to the at least one beam.
[0008] The chamber further has an interior surface, which may be
curvilinear, rectilinear or combinations thereof. Furthermore, a
portion or the entire interior surface may have various
characteristics including highly reflective properties, surface
undulations (linear or curvilinear) or features to assist in beam
scattering or intended beam redirection. Moreover, the interior
surface may be rigid or flexible. If flexible, the surface may be
acted upon by a force (mechanical, electrical or pneumatic) to
cause deflection thereof. In certain embodiments, the deflection is
cyclical and characterized as a vibration. Optional optical baffles
prevent continued propagation of beam energy outside the confines
of the chamber, or may be positioned within the functional portion
of the chamber to increase distribution of radiation energy and/or
modify air transport characteristics.
[0009] The at least one beam of collimated electromagnetic
radiation is characterized as having at least one discrete
frequency or wavelength and preferably a plurality of wavelengths
chosen to have particular efficacy at neutralizing the suspended
micro-objects. The plurality of discrete wavelength ranges may be
serially delivered to the chamber or may be simultaneously
delivered. Neutralization includes destruction of the micro-object,
functional disruption of the micro-object (as used herein, function
disruption has particular applicability to rendering pathogens
inactive or substantially biologically harmless), and vaporization
of the micro-object. As used herein, "discrete wavelength" refers
to a single wavelength and adjacent wavelengths within a small
range thereof, e.g., those within about 1% of the primary
wavelength.
[0010] The introduced at least one beam of collimated
electromagnetic radiation can be a single beam of energy. In such
an embodiment, the energy density of the beam can be diffused
throughout the chamber by modifying the interior surface of the
chamber to effect the desired beam diffusion or redirection.
Alternatively, the introduced at least one beam of collimated
electromagnetic radiation can be multiple beams of energy. In such
an embodiment, a single beam is either divided into a plurality of
beams prior to entering the chamber, with each beam having a unique
angle of incidence when entering the chamber, or a single beam is
optically redirected prior to entering the chamber such that each
beam redirection results in the entering beam has a unique angle of
incidence when entering the chamber. The former can be accomplished
by passing the beam through a beam splitter or diffractive element,
while the later can be accomplished by passing the beam through or
reflecting the beam off a movable element. Alternative means for
distributing the at least one beam include selectively removing the
cladding from a fiber optic or periphery of a light pipe to permit
partial escapement of any energy within the fiber or light pipe.
Those persons skilled in the art will appreciate that the geometry
of such material removal will create unique dispersion
characteristics that may be matched to the particular environment
in which the dispersion is desired.
[0011] The source of the at least one beam of collimated
electromagnetic radiation is preferably a laser having a power
output sufficient for achieving the intended purpose of the
apparatus and methods. The laser may be of the continuous wave or
pulsed type, with many preferred embodiments employing a pulsed
type for reasons well known to those skilled in the art. Depending
upon the energy density for a given application, a 10 watt CO.sub.2
laser emitting radiation in the infrared region may be sufficient,
or higher power and/or additional lasers may be employed. Again,
the wavelength of the laser or ultimately emitted beam(s) is
selected based upon the target species identified for
neutralization.
[0012] To ensure that air having exited the air sterilization
apparatus has been appropriately treated, various embodiments of
this series may employ a particulate matter feedback arrangement.
The feedback arrangement preferably comprises a backscatter
detector operatively exposed to the air stream during or after
treatment by the invention, and to either a portion of the at least
one beam of collimated electromagnetic radiation or a separate
source such as an optical wavelength laser. The detector, commonly
at least one photovoltaic element, is positioned to either receive
backscattered light or transmitted light, depending upon the mode
of implementation, created by the interaction of suspended matter
in the air stream with the radiation. By transforming the modulated
signal output of the detector into discernable data, a
determination can be made regarding the efficacy of the air
sterilization apparatus for the parameters being employed. If, for
example, the resulting data indicates an unacceptably high level of
suspended matter exists, or if the feedback arrangement can discern
particle characteristics and such data indicate the presence of
undesired matter, the operational parameters of the apparatus can
be modified to address the undesired conditions. Such adjustable
parameters may be the air stream velocity which affects the
residency of an air mass within the apparatus, the intensity or
energy density of the at least one beam, pulse width of the at
least one beam if variable, beam scattering parameters and so on.
In addition or alternatively thereto, an air stream redirector or
damper can be activitated to return the undesired air stream back
to the input of the apparatus for further treatment, this option
being employed when the feedback arrangement is located after the
exposure cavity of the apparatus.
[0013] In certain embodiments of this series, the air sterilization
apparatus is portable, i.e., not integrated with or part of a
permanent or semi-permanent structure (non-deployable assets). In
these embodiments, the apparatus may further comprise an air
handler, e.g., a blower having an air displacement element and a
motor, and the outlet of the chamber is adapted to fluidly couple
with a portable structure such as a container or other
transportable rigid structure, or couple with errectable structures
such as hazardous materials tents, field medical tents and related
medical temporary structures, neonatal care tents, burn recovery
tents, and other inflatable tents. Preferably, either type of
structure is relatively sealable from an external environment
whereby the apparatus provides sterilized air to the interior of
the structure and further creates/maintains some level of positive
pressure within the structure relative to the environment's
atmospheric pressure adjacent to the structure, thus minimizing the
undesirable ingress of unconditioned air. The apparatus can be
discrete from the structure whereby only a duct or similar air
transport conduit is used to operative link the apparatus to the
structure, or the apparatus can be integrated with the structure
whereby the outlet of the chamber is directly exposed to the
interior space of the structure. The optional air handler can be
located either upstream or downstream of the apparatus, depending
upon design considerations.
[0014] With respect to portable air sterilization apparatus, it may
be desirable to have the apparatus operate off grid. In these
embodiments, the apparatus further comprises a power source. The
power source may comprise a power generator utilizing an internal
or external combustion engine to provide mechanical energy to a
suitable electrical generator, the power source may be a battery
(rechargeable or not), or the power source may be a fuel cell. For
critical applications such as military or first responder
environments, fuel cells provide a convenient and reliable means
for providing the necessary power to operate even high power lasers
and optionally air handlers.
[0015] In certain embodiments of this series, the apparatus is
integrated into vehicle platforms such as land vehicles, water
craft and aircraft. These vehicle platforms are chosen due to their
intrinsically controlled internal environment. Using an aircraft
platform as an example, the air sterilization apparatus is placed
preferably downstream of any air conditioning packs that may be
present on the aircraft, otherwise as close to the external air
intake(s) as possible. The chamber inlet end and outlet end are
operative coupled to the main air flow such that all air to be
delivered to the interior areas of the aircraft, e.g., cabin and
cockpit, must necessarily pass through the apparatus. Power for the
apparatus is obtained from the aircraft power harness, taking into
account obvious requirements for voltage and load matching. Upon
activation of the apparatus, all air being delivered to the
interior areas of the aircraft is subjected to sterilization.
Moreover, if intelligently integrated into the aircraft
environmental controls, recirculated air is also subjected to
re-sterilization thereby addressing issues of contamination
originating from within the interior areas of the aircraft. Similar
integration approaches can be taken with respect to other vehicle
platforms, however, only those with controlled environments will
particularly benefit from the sterilization benefits of the
apparatus.
[0016] In another series of embodiments, the invention is optimized
to affect relatively large objects suspended in a chamber.
Throughout this patent, this embodiment is referenced as an object
sterilization apparatus. The object sterilization apparatus
comprises a chamber having a sealable orifice wherein objects of
interest can be introduced and removed by a user. Disposed in the
chamber are means for temporarily positioning the object(s) to be
sterilized in the chamber. The chamber also defines a window
through which at least one beam of collimated electromagnetic
radiation can pass into the chamber. The window may be an opening
or preferably may be an opening in which a material substantially
transparent to the at least one beam is located. Alternatively, the
source of radiation can be disposed within the chamber, thereby
eliminating the requirement for a window or other transmissive
means.
[0017] The chamber further has an interior surface, which may be
curvilinear, rectilinear or combinations thereof. Furthermore, a
portion or the entire interior surface may have various
characteristics including highly reflective properties, surface
undulations (linear or curvilinear) or features to assist in beam
scattering or intended beam redirection. Moreover, the interior
surface may be rigid or flexible. If flexible, the surface may be
acted upon by a force (mechanical, electrical or pneumatic) to
cause deflection thereof. In certain embodiments, the deflection is
cyclical and characterized as a vibration.
[0018] The at least one beam of collimated electromagnetic
radiation is characterized as having at least one discrete
frequency or wavelength and preferably a plurality of wavelengths
chosen to have particular efficacy at neutralizing the suspended
micro-objects. The plurality of discrete wavelength ranges may be
serially delivered to the chamber or may be simultaneously
delivered. Neutralization includes destruction of the micro-object,
functional disruption of the micro-object (as used herein, function
disruption has particular applicability to rendering pathogens
inactive or substantially biologically harmless), and vaporization
of the micro-object. As used herein, "discrete wavelength" refers
to a single wavelength and adjacent wavelengths within a small
range thereof, e.g., those within about 1% of the primary
wavelength.
[0019] The introduced at least one beam of collimated
electromagnetic radiation can be a single beam of energy. In such
an embodiment, the energy density of the beam can be diffused
throughout the chamber by modifying the interior surface of the
chamber to effect the desired beam diffusion or redirection.
Alternatively, the introduced at least one beam of collimated
electromagnetic radiation can be multiple beams of energy. In such
an embodiment, a single beam is either divided into a plurality of
beams prior to entering the chamber, with each beam having a unique
angle of incidence when entering the chamber, or a single beam is
optically redirected prior to entering the chamber such that each
beam redirection results in the entering beam has a unique angle of
incidence when entering the chamber. The former can be accomplished
by passing the beam through a beam splitter or difractive element,
while the later can be accomplished by passing the beam through or
reflecting the beam off a movable element. Alternative means for
distributing the at least one beam include selectively removing the
cladding from a fiber optic or periphery of a light pipe to permit
partial escapement of any energy within the fiber or light pipe.
Those persons skilled in the art will appreciate that the geometry
of such material removal will create unique dispersion
characteristics that may be matched to the particular environment
in which the dispersion is desired.
[0020] The source of the at least one beam of collimated
electromagnetic radiation is preferably a laser having a power
output sufficient for achieving the intended purpose of the
apparatus and methods. The laser may be of the continuous wave or
pulsed type, with many preferred embodiments employing a pulsed
type for reasons well known to those skilled in the art. Depending
upon the energy density for a given application, a 10 watt CO.sub.2
laser emitting radiation in the infrared region may be sufficient,
or higher power and/or additional lasers may be employed. Again,
the wavelength of the laser or ultimately emitted beam(s) is
selected based upon the target species identified for
neutralization.
[0021] The means for temporarily positioning an object in the
chamber preferably comprises a substantially transparent platform
for receiving the object, the degree of transparency being a
function of the nature of the introduced electromagnetic radiation,
e.g., its frequency and energy density. In this manner, the object
to be sterilized is optically coupled to the at least one beam, and
is subject to direct and/or reflected energy thereof. Alternative
means for temporarily positioning an object in the chamber comprise
substantially transparent clamps, tongs or other similar
compressive devices. Note that the requirement for transparency
only applies to those portions of the means that would otherwise
interfere with the object's exposure to the beam.
[0022] To enhance the exposure of objects in the chamber to the
radiation, the objects may be moved therein such as by carousel,
conveyor, gantry, or other movable support platform. By moving
objects in the chamber, portions of the objects that might
otherwise be occluded from exposure thereto are repositioned to
locations that optimize exposure. Moreover, by moving the objects
through the exposure chamber, continuous process apparatus can be
constructed where objects are introduced in one end and exit in a
sterilized state at another end, much as with the air stream in the
air sterilization apparatus.
[0023] While many embodiments of the object sterilization apparatus
will use site-available power, this apparatus too can be modified
to operate off grid. Therefore, alternative power sources for
operation include a power generator utilizing an internal or
external combustion engine to provide mechanical energy to a
suitable electrical generator, a battery (rechargeable via, e.g., a
solar array or not), or a fuel cell. For remote applications such
sterilization operations in remote areas in third world countries,
fuel cells provide a convenient and reliable means for providing
the necessary power to operate even high power lasers; ubiquitously
available methanol or ethanol can be used to power the
apparatus.
[0024] Heretofore, the object sterilization apparatus comprised a
chamber with only one sealable opening. However, certain
applications may require mass object or continuous object
sterilization operations. In such situations, the chamber can be
modified to have a first opening and a second opening, and the
means for temporarily positioning an object in the chamber
comprises a movable conveyor portion utilizing a transparent belt
or linked tread whereby objects can be introduced on the conveyor
portion at the first opening and removed therefrom at the second
opening. Because the object sterilization apparatus does not rely
upon heat and/or pressure, the openings can be in communication
with the external environment, with beam energy being attenuated by
the use of an optical curtain that permits the conveyor and objects
to exit the influence of the at least one beam prior to removal of
the objects from the chamber. The conveyor portion may be motorized
or hand operated, e.g., hand-wound torsion spring with escapement
for moving conveyor portion. In an alternative arrangement, a
"slide" is employed wherein the object to be sterilized is placed
on an upper end of the slide via the first opening and permitted to
move by the force of gravity to a lower end of the slide, which is
proximate to the second opening of the chamber. During the transit,
the object is exposed to the at least one beam and thereby
sterilized. As with the previously described embodiments of this
series, the slide is constructed of a material substantially
transparent to the beam.
[0025] Applications for the object sterilization apparatus are
primarily directed to those applications in which a hand tool or
other similarly sized object is to undergo sterilization. Thus,
reusable medical and dental instruments may be placed in the object
sterilization apparatus and exposed to the at least one beam. After
a predetermined time period (dependent upon the nature of the
object placed in the apparatus), the object is removed from the
apparatus in a sterilized state. A benefit of the object
sterilization apparatus over that of a conventional autoclave is
that there is no "warm up" period; the apparatus is instantly
available for sterilization procedures. Another benefit is that the
object can be removed very quickly from the apparatus after
sterilization unlike an autoclave; the surface of the instrument
either reflects the energy or very briefly may absorb a portion of
the energy without appreciable heating of the instrument. Moreover,
because of the limited duration for energy transfer to the
instrument, instruments traditionally unsuitable for autoclave
sterilization can be used and sterilized.
[0026] In still another series of embodiments, the at least one
beam of collimated electromagnetic radiation is directed into a
light pipe or fiber optic bundle of low attenuation material such
as zinc selenide. Suitable dispersion features are created in the
pipe or bundle so as to emit the radiation in at least a partially
lateral direction. This probe embodiment find particular utility
for sterilizing holly cylindrical bodies such as endoscopes and the
like, where radiation would otherwise be prevented from entering
for example, when exposed to the object sterilization
apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic perspective view of a first air
sterilization apparatus embodiment utilizing a rotating optic
element to create numerous beams of energy in a chamber;
[0028] FIG. 2 is a schematic perspective view of a second air
sterilization apparatus embodiment utilizing a beam diverging
element to create a single "fan" of energy in a chamber;
[0029] FIG. 3 is a perspective view of a light baffle to permit
movement of air from one end thereof to another end, but attenuate
laser energy; and
[0030] FIG. 4 is a schematic perspective view in cross section of
an object sterilization apparatus embodiment utilizing a beam
diverging element to create a single "fan" of energy in a chamber
and a slidable transparent tray to receive objects to be
sterilized.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] The following discussion is presented to enable a person
skilled in the art to make and use the invention. Various
modifications to the preferred embodiments will be readily apparent
to those skilled in the art, and the generic principles herein may
be applied to other embodiments and applications without departing
from the spirit and scope of the present invention as defined by
the appended claims. Thus, the present invention is not intended to
be limited to the embodiments shown, but is to be accorded the
widest scope consistent with the principles and features disclosed
herein.
[0032] As described above, the invention is broadly characterized
as a ported chamber into which at least one beam of collimated
light energy is directed. The two embodiment series described below
are functionally related. The air sterilization apparatus of FIGS.
1-2 have two openings for accepting air and delivering air while
the object sterilization apparatus has only one, which is sealable.
Furthermore, in the illustrated embodiments a 10 or 25 watt laser
is used. The laser, sold by Synrad, Inc. under the "Series 48"
designation, is a pulsed CO.sub.2 laser emitting infrared
collimated energy in the 10.60 micron range, and is FDA approved.
Operational control of the laser (duty cycle and intermittent
control) is preferably carried out by a personal computer
operatively linked to the laser via a serial data cable interface
provided on the lasers.
[0033] For embodiments requiring multiple wavelength light, any
known means for shifting the native frequency or frequencies of the
laser can be employed. Such shifting can be done sequentially over
time (serial shifting), or the beam can be split and the resulting
plurality of beams shifted as appropriate (parallel shifting). The
selection of desired frequencies is dependent, in large part, upon
the operational criteria of the apparatus, e.g., if the target of
the sterilization process is biologic pathogens, then a certain
suite of frequencies (wavelengths) are selected over other
frequencies that are targeted to inorganic micro-objects. The
selection of various wavelengths for each type of targeted
micro-objects is well within the knowledge of those persons skilled
in the art and will not be repeated here.
[0034] Turning then to FIG. 1, a first air sterilization apparatus
embodiment utilizing a rotating optic element to create numerous
beams of energy in a chamber is schematically shown. Apparatus 10
comprises chamber 20, which includes a plurality of exterior walls
26 that define first end 22 and second end 24 (thereby defining a
longitudinal axis between these two ends) as well as window 30.
Chamber 20 may be normal at all wall intersections or may be formed
to diverge from first end 22 to second end 24, thus aiding in beam
propagation. While not shown in this schematic representation, ends
22 and 24 are preferably adapted to integrate into the structure to
which apparatus 10 is intended, as will be described below.
[0035] Interior walls 28 are preferably highly reflective of
entering laser beam 42 so that beam 42 is repeatedly reflected
within the volume defined by interior walls 28. The material used
to achieve high reflectivity is chosen in view of the wavelength of
the laser beam, however, surface treatments to interior walls 28 to
facilitate propagation of the beam include forming linear and/or
non-linear ridges and troughs at selected angles to the
longitudinal dimension of the chamber; convex protrusions (faceted,
smooth or combinations thereof); concave dimples (faceted, smooth
or combinations thereof); regular protrusions and/or dimples;
irregular protrusions and/or dimples; and smooth surfaces. The
objective to surface treatments is to maximize at least one of the
energy density within a particular volume within the chamber or
total exposure time for any micro-object within the chamber as it
traverses it.
[0036] FIG. 1 shows beam-type laser 40 directing beam 42 towards
beam redirector 50. Beam redirector is shown schematically as
comprising high speed stepper motor 52 to which optic element 54,
constructed to include a suitable reflective material, is mounted
via shaft 56. Redirected beam 42' then enters chamber 20 via
transparent window 30, and repeatedly reflects within the interior
of chamber 20. In operation, element 54 rotates so that a variety
of entrance incident angles are created by beam 42', thereby
distributing energy within chamber 20. To prevent errant
reflection, controller 70 interfaces with laser 40 to switch it on
and off in synchronicity with the operation of motor 52, which is
also operatively linked to controller 70 in well known ways. In
this manner, beam 42 is only presented to element 54 when
redirected beam 42' is certain to pass through window 30. When
coupled to a source of moving air, air entering first end 22 is
exposed to laser beam energy prior to passing out of chamber 20 via
second end 24.
[0037] In the event that a different dispersion pattern is desired,
the configuration of the apparatus in FIG. 2 may be used. Chamber
20 remains essentially the same although the reflective properties
of interior walls 28 may be modified in view of the unique
variables introduced through the use of this embodiment. In this
embodiment, a beam expanding or diverging element is used to create
a line as opposed to a point. The result is a "fan" of beam energy
44, which is again reflected many times within the volume of
chamber 20. While not shown in this embodiment, moving optics can
be employed to cause movement of beam 44, although the nature of
the beam decreases the need for a sweeping action, other factors
being equal.
[0038] To limit unintentional egress of beam energy from chamber
20, a pair of optic baffles such as shown in FIG. 3 may be used.
Housing 80 provides suitable support for a plurality of offset
baffles 82, which permit air flow thereby but occlude any direct or
indirect beam from exiting chamber 20. Baffles 82 can be
constructed from any suitable material that absorbs and/or reflects
beam energy. If the baffles absorb the energy, it may also be
desirable to include means for cooling the baffles if the air flow
rate is insufficient for the task.
[0039] FIG. 4 schematically illustrates the adaptation of the
embodiment shown in FIG. 2 into an object sterilization apparatus.
Here, first end 22 (shown in phantom) is closed and includes
another interior wall 28. Tray 90 is supported by guides 94 present
in opposing lateral walls 28. Optional mechanics translate tray 90
to provide maximum exposure of any object placed thereon to beam
44.
* * * * *