Breaking NEWz you can UzE...
compiled by Jon Stimac
Technology Aids State Police in Charge
PRESS & SUN BULLETIN, NY
- Apr 6, 2007 ...using new fingerprint technology available
to them, state police determined within 30 minutes that the mans
DAILY RECORD, UK -
2007 ...police will soon have access to
fingerprint technology able to help bring crooks to justice within
Tellers Finger Band-Aid Bandit
FOX TAMPA BAY, FL
- Apr 4,
2007 ...he left no fingerprints because the bandit covered
his fingertips with Band-Aids...
Pollen Makes it Hard for Police to Get Fingerprints
SARASOTA-HERALD TRIBUNE, FL
- Apr 2, 2007
...the heavy pollen across the Southeast this spring is giving
criminals a helping hand...
Recent CLPEX Posting Activity
containing new posts
Moderated by Steve Everist and Pat Wertheim
Idea on blind verification
Becky 3139 Fri Apr 06, 2007 1:16 am
Pollen impedes finding prints
L.J.Steele 270 Thu Apr 05, 2007 5:08 pm
Daubert Debate in MD
L.J.Steele 1892 Tue Apr 03, 2007 11:25 pm
Looking up old posts
Stephany Louk-Denney 152 Tue Apr 03, 2007 8:42 pm
ACE-V In The SOP
Charles Parker 866 Tue Apr 03, 2007 8:31 pm
Michele Triplett 744 Mon Apr 02, 2007 4:04 pm
Thomas Taylor 296 Sun Apr 01, 2007 10:23 pm
UPDATES ON CLPEX.com
updates on the website this week.
we continued a series on U.S. patents related to
latent print examination.
we continue this series
with a patent application involving a sustaining cyanoacrylate fume
Cyanoacrylate Fume Applicator
Authored by Walter Nichols; et al.
What is claimed is:
1. A fingerprint detection apparatus, comprising: a liquid source containing
a solution which upon
vaporization and contact with a surface to be inspected can provide an image
of a fingerprint; a flow
passage in fluid communication with the liquid source; a valve operable to
control flow of liquid from
the liquid source to the flow passage; a heater arranged to heat the
solution in the flow passage into a
gaseous state; and an optional switch operable to activate the valve and the
heater such that solution
flowing through the flow passage is vaporized and directed outwardly from
2. The fingerprint detection apparatus of claim 1, wherein the flow passage
comprises a capillary tube
having a maximum diameter of 0.01 to 10 mm.
3. The fingerprint detection apparatus of claim 2, wherein the capillary
tube comprises a metal tube and
the heater comprises a section of the capillary tube which is heated by
resistance heating thereof.
4. The fingerprint detection apparatus of claim 1, wherein the apparatus
includes a receptacle receiving
the liquid source and the liquid source is a replaceable cartridge.
5. The fingerprint detection apparatus of claim 1, wherein the apparatus
includes the switch and a power
supply, the switch being operable to open the valve and connect the power
supply to the heater.
6. The fingerprint detection apparatus of claim 1, wherein liquid source
includes a spring biased plunger
operable to force liquid out of the liquid source.
7. The fingerprint detection apparatus of claim 1, wherein the heater
comprises a layer of resistance
heating material located along the flow passage.
8. The fingerprint detection apparatus of claim 5, wherein the power supply
comprises at least one
battery and a voltage regulator, the voltage regulator being operable to
supply a selected voltage to the
9. The fingerprint detection apparatus of claim 1, wherein the solution
comprises a cyanoacrylate
10. A method of using the fingerprint detection apparatus of claim 1,
comprising flowing the solution
through the flow passage while heating the flow passage with the heater,
forming a vapor by vaporizing
the solution, and directing the vapor onto a surface to be inspected.
11. The method of claim 10, wherein the solution comprises a cyanoacrylate
12. The method of claim 11, wherein the cyanoacrylate solution comprises a
mixture of cyanoacrylate
monomer and a solvent.
13. The method of claim 12, wherein the cyanoacrylate solution comprises 1
to 20% by volume of the
14. The method of claim 10, further comprising pressing the switch to open
the valve and activate the
15. The method of claim 10, further comprising replacing the liquid source
with a replaceable cartridge
containing a cyanoacrylate solution.
16. The method of claim 10, wherein the solution is supplied to the flow
passage by pressurizing the
17. The method of claim 10, further comprising forming an image of a latent
fingerprint by reacting the
vapor with organic compounds of the fingerprint.
18. The method of claim 10, wherein the solution includes a soluble
fluorescent dye and the method
includes generating a fluorescent vapor which is directed at the surface to
19. The method of claim 10, wherein the apparatus is a portable hand held
apparatus and the method
includes holding the apparatus in a user's hand while directing the vapor at
the surface to be inspected.
20. The method of claim 10, wherein the flow passage is a capillary sized
passage having a maximum width
of 0.01 to 10 mm or transverse area of 8.times.10.sup.-5 to 80 mm.sup.2.
 1. Field of the Invention
 The present invention is directed generally to making latent
fingerprints visible and
semipermanent. More specifically, the present invention is related to a
method and apparatus for
vaporizing a liquid cyanoacrylate composition that polymerizes upon contact
with the fingerprint.
 2. Background Information
 It is known that cyanoacrylate can be used to develop fingerprints
through a polymerization
reaction in which cyanoacrylate vapor contacts a latent fingerprint.
Chemicals in the fingerprint cause
the polymerization of the cyanoacrylate resulting in an enhanced visual
image of the print.
 U.S. Pat. Nos. 5,424,092; 5,348,759; 5,342,645; 4,613,515; 4,550,041;
4,461,235; and 4,407,842
relate to apparatus and methods for developing latent fingerprints using
cyanoacrylate. U.S. Pat. Nos.
4,700,657; 4,461,235 and 4,294,383 disclose closed fingerprint detection
systems using cyanoacrylate.
U.S. Pat. Nos. 5,462,597 and 5,395,445 disclose methods for detecting
fingerprints on skin.
 The '092 and '759 patents, for example, disclose a housing containing
a thermally stable porous
material that is impregnated with a liquid cyanoacrylate, which is allowed
to cure. A portable heating
device such as a propane torch can be used to vaporize the cyanoacrylate,
which is propelled toward the
object to be tested by the torch exhaust.
 The '515, '041 and '235 patents disclose a method and apparatus
whereby vapors are generated from
a thin film of a storage stable cyanoacrylate monomer composition that has
been complexed to render the
composition substantially non-flowable. An envelope package for the monomer
composition may be peeled
open to expose the inner surfaces coated with a film of the composition.
 The methods and apparatus described above are slow to display the
fingerprints and, in some
instances, require that the target area be placed in a sealed container.
Accordingly, there is a need for
a portable, rapid, simple and safe method for rendering latent fingerprints
SUMMARY OF THE INVENTION
 The invention relates to a fingerprint detection apparatus comprising
(a) a liquid source
containing a solution, such as a cyanoacrylate solution, which upon
vaporization and contact with a
surface to be inspected can provide an image of a fingerprint; (b) a flow
passage in fluid communication
with the liquid source; (c) a valve operable to control flow of liquid from
the liquid source to the flow
passage; (d) a heater arranged to heat the solution in the flow passage into
a gaseous state; and (e) an
optional switch operable to activate the valve and the heater such that
solution flowing through the flow
passage is vaporized and directed outwardly from the apparatus.
 The flow passage preferably comprises a capillary tube, such as a
metal tube, having a maximum
diameter of 0.01 to 10 mm or the flow passage comprises a capillary sized
opening of any configuration
having a maximum width of 0.01 to 10 mm or transverse area of
8.times.10.sup.-5 to 80 mm.sup.2. The
heater can comprise a section of the capillary tube which is heated by
resistance heating thereof or the
heater can comprise a layer of resistance heating material located along the
 The apparatus may include a receptacle for receiving the liquid
source such as a replaceable
cartridge. For delivery of the liquid, the liquid source can include a
spring biased plunger operable to
force liquid out of the liquid source.
 The apparatus may further include a power supply, the switch being
operable to open the valve and
connect the power supply to the heater. The power supply may comprise at
least one battery and a voltage
regulator, the voltage regulator being operable to supply a selected voltage
to the heater.
 The cyanoacrylate solution may comprise a mixture of cyanoacrylate
monomer and a solvent and may
comprise 1 to 20% by volume of the cyanoacrylate monomer. The solution can
also include a soluble
fluorescent dye that can generate a fluorescent vapor that is directed at
the surface to be inspected.
 The invention also relates to a method of using the fingerprint
detection apparatus comprising (a)
flowing the solution through the flow passage while heating the flow passage
with the heater; (b) forming
a vapor by vaporizing the solution; and (c) directing the vapor onto a
surface to be inspected.
 The apparatus can be used as a portable hand held apparatus that can
be held in a user's hand
while directing the vapor at the surface to be inspected by using the switch
to open the valve and
activate the heater. The solution can be supplied to the flow passage by
pressurizing the liquid source.
Furthermore, the liquid source can comprise a replaceable cartridge
containing a cyanoacrylate solution.
An image of a latent fingerprint can be formed by allowing the vapor to
react with organic compounds of
BRIEF DESCRIPTION OF THE DRAWING FIGURES
 Various features and advantages of the invention will become apparent
from the following detailed
description of preferred embodiments in connection with the accompanying
drawing in which like numerals
designate like elements and in which:
 FIG. 1 is a cross-sectional view of an apparatus useful for carrying
out a preferred method in
accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Fingerprints can fall into one of several different classifications,
e.g. visible, impression, and
latent. Investigators typically seek to obtain a portable, permanent copy of
a fingerprint, such as a
photograph. Visible fingerprints can be photographed directly, and
impression fingerprints can usually be
photographed under special lighting conditions. Latent fingerprints,
however, which are invisible to the
eye, are difficult to photograph.
 Cyanoacrylate fuming is a chemical technique for making latent
fingerprints visible. Latent
fingerprints are composed of several chemicals exuded through pores in the
fingertips that are left on
objects which are touched. The primary component of latent fingerprints is
water, which will evaporate
after a fairly short period of time. The solid components of latent
fingerprints, however, can remain on
a surface for a much longer period of time. These other components include
organic compounds like amino
acids, glucose, lactic acid, peptides, ammonia, riboflavin, and
isoagglutinogens as well as inorganic
chemicals like potassium, sodium, carbon trioxide, and chlorine.
 Cyanoacrylates can react with the moisture in the air and the traces
of amino acids, fatty acids,
and proteins in a latent fingerprint to produce a visible, sticky white
material that forms along the
ridges of the fingerprint and visually enhances the fingerprint. Exposure of
gaseous cyanoacrylate to the
fingerprint in the presence of atmospheric humidity can trigger the
reaction. When cyanoacrylate monomer
contacts the fingerprint, it can polymerize by anionic vinyl polymerization,
which is a type of vinyl
polymerization that is begun in the presence of an initiator. Water from the
air or trace amounts of
moisture on the surface to be tested can serve as the initiator. The
resulting image can be photographed
directly or following further enhancement.
 For example, after developing the fingerprint image by exposing the
latent print to cyanoacrylate
vapor, the image of the fingerprint may not be easy to photograph. The
chemical deposits left by the
reaction with the cyanoacrylate are white and may provide insufficient
contrast for an effective
photograph, particularly if the background surface is also white. To enhance
imaging, different colored
dusts, which will cling to the cyanoacrylate residue, may be brushed onto
the image of the fingerprint.
 Referring to FIG. 1, there is shown an exemplary apparatus 10 for
rendering latent fingerprints
detectable. The apparatus comprises a reservoir 20 that contains a volume of
cyanoacrylate solution 30. A
spring-loaded piston 40 or other suitable pressurizing arrangement maintains
the solution in the
reservoir under pressure. Upon loading of a reservoir 20 in the apparatus
10, spring 50 is compressed
such that piston 40 provides a pressurizing force on movable plunger 70 of
the reservoir. Thus, solution
is removed from the reservoir 20 due to pressure of piston 40 on plunger 70.
The apparatus includes valve
80, which provides fluid communication between the reservoir 20 and an inlet
90a of a capillary flow
passage in the form of a capillary tube 90 via connections 80a and 80b. The
outlet end of the capillary
tube 90b is open to atmosphere. The capillary tube 90 is preferably made of
stainless steel, but can be
any electrically conductive material. Alternatively, the flow
passage can be in a non-electrically conductive material and heated by a
heater arrangement extending
along the flow passage. The valve 80 is preferably activated by an on/off
switch 130 which allows the
user to control the flow of the solution from the reservoir into the flow
 The apparatus also comprises a voltage regulator 100. The use of the
voltage regulator allows the
apparatus to be made economically by obviating more expensive control
circuitry. That is, the voltage
regulator supplies stepped down power from a power source to the heated flow
passage when the on/off
switch 130 opens valve 80. The voltage regulator can be a 3-10 V in/2 V out
regulator; however, persons
with ordinary skill in the art will recognize that the input and output
voltages of the voltage regulator
can be selected to accommodate other parameters of the apparatus, such as
the resistivity of the heater
and/or the desired temperature of the flow passage during operation.
 The input to the voltage regulator is connected to a battery pack
110, which supplies DC power to
the voltage regulator. The battery pack can comprise, for example, four 1.2
V rechargeable Ni-MH "AA"
batteries. The output to the voltage regulator is connected to connecting
wires 120a, 120b via on/off
switch 130, which is normally off. The connecting wires are, in turn,
connected to spaced-apart locations
along the capillary tube, preferably the anterior and posterior ends of the
capillary tube 90a, 90b. When
the switch 130 is turned "on" the voltage regulator supplies sufficient
power to the capillary tube to
cause resistance heating of the capillary tube and vaporization of the
liquid supplied to the capillary
 Connecting wires 120a, 120b can be attached to the exterior of the
capillary tube using any
suitable electrical connection, such as solder, weld, braze or a mechanical
connection such as a clamping
arrangement. The application of a voltage across the connecting wires causes
the temperature of the
capillary tube between the connecting wires to increase due to resistance
heating of the tube. It will be
appreciated by those skilled in the art that the temperature of the
capillary tube is a function of the
distance, d, between the connecting wires, the resistivity and cross
sectional area of the capillary
tube, as well as the applied voltage. Thus, both the temperature and
temperature distribution across the
capillary tube can be adjusted to provide optimized vaporization of the
cyanoacrylate solution as it
passed through the capillary tube.
 Advantageously, the heating of the capillary tube by the application
of a constant voltage is
nearly instantaneous. Likewise, the capillary tube cools very rapidly when
the voltage is removed. Thus,
there is very little incubation or heat-up time needed before the apparatus
is ready for use.
 In order to vaporize the cyanoacrylate solution, the capillary tube
is preferably brought to a
temperature above the boiling point ("bp") of the solution. For a
cyanoacrylate (bp .about.55.degree. C.)
and propylene carbonate (bp .about.242.degree. C.) solution, for example,
the temperature of the
capillary tube is from between about 240 to 270.degree. C., preferably
250.degree. C. Because liquid
flows through the capillary tube while it is heated, the temperature of the
capillary tube can be
maintained in a desired temperature range.
 The switch 130 activates valve 80 such that the valve opens when
switch 130 is turned on when "on"
and the valve closes when switch 130 is turned "off".
 The apparatus can be enclosed in housing 140, which has an opening
145 at the distal end of the
apparatus to allow the vaporized solution to exit the capillary tube and be
applied to the object or
surface to be tested. The housing 140 can be formed of any suitable material
such as plastic or metal.
The housing can keep hot surfaces of the apparatus 10 from coming into
contact with the user or other
 In operation, when switch 130 is turned "on" the voltage regulator
supplies power to the capillary
to be 90, which causes the capillary tube to be heated. Also, when switch
130 is turned "on" the valve 80
is opened such that solution 30 flows from reservoir 20 into the capillary
tube 90 where it vaporizes as
it passes through the capillary tube. The cyanoacrylate vapor as it emerges
from the capillary tube can
be directed at the area to be tested and as the vapor comes into contact
with latent fingerprint residue
the cyanoacrylate polymerizes to expose an image of the print.
 When switch 130 is closed, valve 80 closes and the supply of power to
the capillary tube is turned
off. Thus, when switch 130 is closed, solution flow through the capillary
tube is stopped and the
capillary tube is allowed to cool.
 The reservoir can be of any suitable volume, such as from 2 to 10 ml,
though it will be
appreciated that larger volumes may be desirable for certain applications.
Preferably the reservoir is a
replaceable cartridge with a seal at one end and which is punctured to allow
flow of liquid into the
valve 80 when the cartridge is inserted into a mating receptacle in the
housing 140. The capillary tube
can be any suitable size and dimensions. The inner diameter of the capillary
tube can be from between
about 0.004 to 0.010 inches and the outer diameter of the capillary tube can
be from between about 0.008
to 0.02 inches. For example, the capillary tube can be about 40 mm long and
have inner and outer
diameters of about 0.006 inches and 0.012 inches, respectively. The
capillary tube can have a diameter of
0.01 and to 10 mm, preferably 0.05 to 1 mm, and more preferably 0.1 to 0.5
mm and a preferred length of
50 to 200 times the width to provide a flow passage of capillary size.
Alternatively, the capillary passage can be of circular or non-circular
cross section and defined by a
transverse cross sectional area of the passage which can be
8.times.10.sup.-5 to 80 mm.sup.2, preferably
2.times.10.sup.-3 to 8.times.10.sup.-1 mm.sup.2 and more preferably
 The liquid flow rate of the cyanoacrylate solution through valve 80
and the capillary tube 90 is
controlled by the viscosity of the solution, the force of the spring 50 and
the inner diameter of the
capillary tube. Preferably, the solution flow rate can be from between about
1 .mu.l/sec to 10 .mu.l/sec.
Thus, by way of example, for a solution flow rate of 2 .mu.l/sec, a 2 ml
reservoir can hold sufficient
solution for approximately 17 minutes of operation.
 The directed vapor that exits the capillary tube can afford an
efficient use of the consumable
cyanoacrylate solution. Furthermore, latent fingerprints that come into
contact with the vaporized
solution become visible to the eye in a very short time. Latent fingerprints
are preferably visible in as
little time as 10-15 seconds. The visible fingerprints can either be
photographed directly or lifted
after application of powder. Thus, the apparatus and method of the invention
can provide an economically
efficient way to detect latent fingerprints.
 A preferred cyanoacrylate solution comprises a mixture of liquid
cyanoacrylate monomer and a
suitable solvent stored in the reservoir. A solvent such as propylene
carbonate prevents the
cyanoacrylate from solidifying or polymerizing in the liquid phase. Liquid
phase storage of the
cyanoacrylate is convenient and capillary tube vaporization of cyanoacrylate
can produce an efficient
vapor that is directed at the area to be tested. Furthermore, unlike pure
cyanoacrylate, the mixture of
the invention does not bond to skin, which can make it easier to use.
 The preferred monomers are cyanoacrylate esters and many are
commercially available as "instant"
adhesives, e.g. Loctite.RTM. Product 420, which is a low viscosity ethyl
cyanoacrylate adhesive. The
cyanoacrylate monomers have the general formula: CH.sub.2.dbd.C(CN)(COOR.-
sub.1) wherein R.sub.1
represents a hydrocarbyl or substituted hydrocarbyl group such as a straight
chain or branched chain
alkyl group having 1 to 12 carbon atoms (which may be substituted with a
halogen atom or an alkoxy
group), a straight chain or branched chain alkene group having 2 to 12
carbon atoms, a straight chain or
branched chain alkyne group having 2 to 12 carbon atoms, a cycloalkyl group,
or an aryl group.
 The cyanoacrylate vapors are most suitably generated from the
monomers. This may be done at
ambient pressure. Cyanoacrylate ester monomers are preferred because of
their ready availability, better
known handling properties and low depolymerization temperatures.
 The cyanoacrylate esters used in the invention can be any suitable
monomer such as methyl
2-cyanoacrylate; ethyl 2-cyanoacrylate; propyl 2-cyanoacrylate; butyl
2-cyanoacrylate; methoxyethyl 2-cyanoacrylate; ethoxyethyl 2-cyanoacrylate;
2-cyanoacrylate; cyclohexyl 2-cyanoacrylate; ethoxycarbonylmethyl
2-cyanoacrylate; and trifluoroethyl
 In addition to propylene carbonate, other suitable solvents can be
used, such as dimethyl
carbonate; diethyl carbonate; ethylene carbonate; diphenyl carbonate;
diethylene glycol bis(allyl
carbonate); 1,3 propanediol bis(allyl carbonate); 1,4 butanediol bis(allyl
carbonate); triethylene glycol
bis(allyl carbonate); trichloroethylene; and acetone. The cyanoacrylate
solution can contain from between
about 1 and 20% by volume, preferably 5 to 15%, and most preferably 10%
cyanoacrylate, with the balance
 It will be appreciated by those skilled in the art that the
development of latent fingerprints can
be accelerated by directing an increased amount of the cyanoacrylate vapor
at the target area. By using
the apparatus of the invention, the development of latent prints can take as
little time as 5 to 25
seconds. The apparatus of the invention provides an economical, safe,
convenient and portable means of
detecting latent fingerprints.
 According to a further embodiment, a soluble fluorescent dye can be
added to the cyanoacrylate
solution. Thus, the apparatus of the invention can generate fluorescent
vapor. When latent fingerprints
are developed using the fluorescent cyanoacrylate vapor, they can be
rendered visible by subsequent
exposure to an ultraviolet light source.
 The fingerprint detection method can be used to create very good
quality fingerprint images on
substantially non-porous surfaces like metal, glass and plastic; and
satisfactory fingerprint images can
be created on porous surfaces.
 Although the present invention has been described in connection with
thereof, it will be appreciated by those skilled in the art that additions,
deletions, modifications, and
substitutions not specifically described may be made without departing from
the spirit and scope of the
invention as defined in the appended claims.
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