|
SureFire Superior Technology
SureFire
illumination tools are the finest in the
world—compact, rugged, powerful, reliable,
efficient. Engineered for maximum
performance and precision manufactured, they
produce optimal beams — brilliant light with
no rings, hot spots, or shadows. That's why
people whose lives may depend on having
enough light when they need it, such as
military, emergency, and police personnel
and outdoors professionals, rely on SureFire.
Anodized Aluminum Alloy Construction
SureFire's aluminum-body WeaponLights are
machined from a high-strength
aerospace-grade alloy, making them extremely
resistant to damage from impact, crushing,
or bending, and allowing them to be made as
small and light as possible without
sacrificing strength. Note: Some of our
lights are made of Nitrolon—see following
section.
SureFire's
Multi-axis Computer Numerically Controlled
lathes ensure precision-machined
components.SureFire's aluminum-body
WeaponLights and flashlights are protected
by a finish called anodizing. The anodizing
process (from anode, the positive side of an
electrical circuit) uses electricity and a
chemical bath to "grow" a layer of aluminum
oxide on an aluminum surface. Aluminum oxide
is the second-hardest substance known to
man, exceeded only by diamond, and certain
anodized finishes can be made extremely
hard, such as the Mil-A-8625 Type III Class
2 military specification finish that
SureFire uses.
Nitrolon®
Some flashlights are made of relatively
cheap polymers (plastics) such as ABS.
SureFire's polymer WeaponLight and
flashlight bodies are made of Nitrolon, a
proprietary high-strength, non-conductive,
impact-resistant, glass-filled polyamide
nylon polymer. "Glass-filled" means that the
polymer matrix has been mixed with fine
glass fibers that add rigidity, abrasion
resistance, and increased stability at
higher temperatures.
Light Output: Candlepower vs. Lumens
The human eye responds most strongly to
light nearest the 560 nanometer wavelength,
which is a yellow-green color. Some
manufacturers dramatize light output
measurements by using candlepower units.
They can get away with this because light
measurement terminology is unfamiliar to
most people. But the basic concepts can be
explained as follows: The science of
measuring light with respect to its effect
on the human eye—which responds differently
according to the wavelength, or color, of
that light—is called photometry. Photometry
includes measuring light intensity in a
particular direction (in units of
candlepower or candelas) and total light
energy in a particular situation (measured
in lumens).
With
illumination tools, a candlepower
measurement doesn't necessarily indicate
total light output. To illustrate this,
imagine representing a flashlight's total
light output as a bag of sugar. If you pour
the sugar onto a table to form a cone and
measure the cone's height (representing the
brightest part of the flashlight beam as
measured in candlepower), you still wouldn't
know the total weight of the sugar
(representing the total light output as
measured in lumens). Conversely, if we shake
the table so that the cone settles and
becomes rounded, the sugar's weight (lumens)
would be the same but the height (brightest
part of the beam) has been lowered and
spread out.
Now take
half the sugar from the demonstration above
and put it inside a narrow conical container
taller than the loose conical piles we made
earlier. Even though this narrow cone's
height (candlepower measurement) is greater
than the previous cones, it contains only
half the sugar (lumens). Reflectors and
lenses are analogous to that conical
container because they can create a light
beam with a high-candlepower "hot spot" that
sounds good in advertisements but tells
nothing about total light output or light
distribution within the beam.
SureFire
uses integrating sphere photometers to
measure the total lumen output of our
illumination tool's, weighted with respect
to human eye response. Other manufacturers
have begun to follow our lead.
For the
record, a lumen is 1/4 π of the total photon
(light) flux emitted by a one-candela
source. One candela is the luminous
intensity of a source whose radiant
intensity is 1/683rd of a watt of
monochromatic light of wavelength 550
nanometers per steradian. A steradian is a
conical figure, or solid angle, whose
intersection with a unit sphere covers one
unit area. Got it?
Xenon/Halogen
Incandescent Lamps
Identical non-SureFire
miniature lamps.
Left lamp is unused,
right lamp shows
tungsten deposits
after several hours
of use. Incandescent
lamps produce light
by using electricity
to heat a small
coiled tungsten
metal wire, which is
enclosed within a
glass "bulb" filled
with special gases,
to a high
temperature — around
2,500 to 3,000
degrees Celsius — at
which point the wire
glows white-hot. The
miniature
incandescent lamps
that SureFire uses
in its WeaponLights
and flashlights are
not typical
off-the-shelf
products. They are
state-of-the-art
devices with the
following features:
Custom Filaments —
The incandescent
lamps ("light
bulbs") used in our
WeaponLights and
flashlights are
designed around a
specific power
supply, light
output, and runtime.
Filament performance
varies according to
wire diameter,
filament length,
filament coil
diameter, total
coils, and
coil-to-coil
proximity. Finally,
the finished
filament must
withstand the
vibration and
G-forces produced by
firearms.
SureFire MN21 lamp,
showing heavy duty
high-output
filament. Xenon Gas
— The high
temperature of the
lamp filament causes
tungsten atoms to
"boil off" and
migrate to the
cooler glass wall of
a lamp, where they
condense to form a
dark light-blocking
layer. Adding a
high-pressure inert
gas inhibits
tungsten boil-off,
which reduces the
rate of tungsten
atom deposition and
lengthens the
operating life of
the lamp. The gas
also permits
increased filament
operating
temperature, which
in turn increases
light output for a
given power
consumption rate.
Argon and krypton
are often used as
the inert fill
gases, but they
don't work as well
as xenon. Although
xenon is much more
expensive, SureFire
uses it exclusively
to provide optimum
lamp performance.
Halogens — To
maximize their
operating life and
light output, some
SureFire lamps
contain a
proprietary mix of
halogens, a family
of elements that
includes fluorine,
chlorine, bromine,
and iodine. Inside a
functioning
incandescent lamp,
tungsten atoms boil
off the filament,
migrate toward the
cooler areas near
the lamp wall, and
combine with halogen
atoms to form a
tungsten halide
vapor. This vapor
migrates back to the
lamp filament, where
high temperature
breaks it down again
into tungsten and
halogen atoms. The
tungsten atoms are
re-deposited on the
filament and the
oxygen and halogen
migrate back toward
the bulb wall to
re-combine with new
boiled-off tungsten
atoms. This
continuous process,
called the halogen
cycle, keeps the
lamp's glass walls
comparatively clean
of light-blocking
tungsten deposits.
Incandescent lamps
produce a broad
spectrum of light
(including infrared)
and can be made to
have a high maximum
lumen output, but
they are
comparatively
inefficient users of
power, and their
lumen output level
is effectively
non-adjustable.
Light-Emitting
Diodes (LEDs)
LED diagram
compliments of
Lumileds Lighting
LLC. An LED (the
acronym for
Light-Emitting
Diode) is a
semiconductor "chip"
that converts
electrical energy
directly into light.
An LED is called a
solid-state light
source because it
has no gas or liquid
components, as do
other light sources.
The LEDs in SureFire
flashlights consists
of the emitter chip
mounted on a solid
base; the chip is
attached to
electrical leads
(wires) that conduct
power to it, and it
is encased in a
clear polymer that
is shaped to either
focus or disperse
the LED's light in
the desired manner.
LEDs generally emit
light within a
narrow spectral
band. In order to
produce white light,
which consists of
the entire visible
spectrum combined
(or nearly so, as
far as the human eye
can discern), we use
LEDs that emit
near-ultraviolet
blue light that
strikes an upper
layer of phosphors.
These phosphors
absorb the blue
light and re-emit
white light, in much
the same manner that
fluorescent light
tubes produce white
light.
LEDs possess some
tremendous
advantages over
incandescent lamps.
First, LEDs can last
thousands of hours
versus less than
fifty hours for
high-output
incandescent lamps.
Second, Photo
showing flat surface
of high-output LED
and surrounding
micro-textured
reflector.because
LEDs are very robust
in construction, and
have no mechanically
delicate parts such
as glass bulbs,
filaments, or
filament supports,
they are extremely
resistant to
vibration and shock,
making them
well-suited for the
combat environment
or for mounting on
firearms. Third,
LEDs produce
virtually no
invisible infrared
radiation, as
opposed to
incandescent lamps,
which emit over 85%
of their output as
infrared, and
therefore LEDs are
much more efficient
in producing light
than incandescent
lamps — an important
factor for
battery-operated
flashlights. And
fourth, they will
emit light over a
wide range of power
input making LEDs
the natural choice
for
adjustable-output
light sources.
As noted above,
there are currently
some disadvantages
to LED light
sources. First, most
LEDs emit forward
from a flat surface,
necessitating more
complex reflectors
and lenses to
produce desirable
beam
characteristics.
Second, because LEDs
are susceptible to
damage from
overheating they
have certain thermal
design requirements.
Therefore,
continuous-use LED
sources currently
have a practical
limit of less than
150 lumens. Third,
LEDs are difficult
to manufacture
without some
variance in lumen
output and color.
For this reason,
they are tested and
sorted by the
manufacturer into
different "bins"
according to output
and color. SureFire
minimizes such
product variability
by purchasing LEDs
only from the
highest-quality
bins.
Electronic Power
Regulation —
SureFire's LED
illumination tools
contain a rugged,
sealed electronic
power regulator that
supervises the
operation of the LED
(with the exception
of the A2 Aviator,
in which the xenon
lamp is regulated).
This circuitry
assesses battery
output, monitors
system performance,
and controls power
supplied to the LED.
Power regulation
provides a more
consistent light
output for the
useable life of the
batteries. Although
any LED may continue
to produce
negligible light
output for up to
several hundred
hours, the amount of
useful light
produced is of a
shorter duration.
Power regulation
circuitry reduces
the amount of
negligible output
and increases the
overall duration of
useful light output.
HID Lamps
High Intensity
Discharge (HID)
lamps do not use a
tungsten filament,
as do incandescent
lamps. Instead they
use a clear quartz
capsule (an "arc
tube") having
electrodes at either
end containing
high-pressure xenon
gas and additional
chemical components.
When sufficient
voltage is applied
to the electrodes
the gas inside the
tube is heated and
ionized, enabling it
to conduct
electricity in the
form of an "arc"
(basically a
sustained electrical
spark), and causing
it to emit light.
When functioning,
pressure inside the
arc tube rises to
several times
atmospheric
pressure.
HID lamps are both
extremely bright and
extremely efficient
— for an equal power
input they produce
more than twice the
lumens of a tungsten
incandescent lamp —
and their operating
life is also several
times that of
comparable
incandescent lamps.
An additional
benefit: since they
have no filament to
break or burn out
they are extremely
resistant to
mechanical shock and
vibration. However,
they are
comparatively large,
requires a
substantial power
source to operate,
and their lumen
output level is
effectively
non-adjustable.
|
|
Electronic
Power Regulation
SureFire's LED
illumination
tools contain a
rugged, sealed
electronic power
regulator that
supervises the
operation of the
LED (with the
exception of the
A2 Aviator, in
which the xenon
lamp is
regulated). This
circuitry
assesses battery
output, monitors
system
performance, and
controls power
supplied to the
LED. Power
regulation
provides a more
consistent light
output for the
usable life of
the batteries.
Although any LED
may continue to
produce
negligible light
output for up to
several hundred
hours, the
amount of useful
light produced
is of a shorter
duration. Power
regulation
circuitry
reduces the
amount of
negligible
output and
increases the
overall duration
of useful light
output.
Beam Pattern
and Reflector
Design
Many flashlights
produce beams
with dark spots
and rings.
SureFire
flashlights and
WeaponLights
produce smooth,
pre-focused
beams. This
"beam pattern"
determines an
illumination
tool's
suitability for
tactical use. It
includes light
distribution, or
the way the
beam's light is
apportioned from
the center
outward, and
irregularities,
such as dark
spots, hot
spots, and
rings.
Irregularities
are caused by
imprecise
reflectors,
improperly
surfaced
reflectors,
filament support
leg shadows, or
"adjustable
focusing" that
only re-arranges
the beam's
defects.
Many
illumination
tools exhibit
inferior beam
character. When
directed at
night on people,
objects, or
surfaces, they
can produce a
view that is
confusing,
misleading, or
even alarming.
For example,
dark or bright
spots in a
moving beam can
be mistaken for
moving objects;
bright rings
tend to seize
our attention.
Hard-edged
beams, like
those of
theatrical
spotlights, can
lack the
surrounding
light necessary
for peripheral
vision. Closeup
photo shows
beam-smoothing
micro-texture on
a SureFire
reflector. This
latter effect
worsens under
stress, when the
brain
concentrates on
central images.
A further
problem occurs
when a
hard-edged beam
causes people
and objects to
appear suddenly
out of the dark,
provoking an
instinctive
startle response
that can trigger
a weapon.
SureFire
reflectors are
designed to
produce optimum
beam character.
Made from CNC-machined
aluminum instead
of stamped metal
or molded
plastic, they
exhibit superior
strength, heat
transfer
capabilities,
and geometric
exactness, the
latter
permitting
precise
placement of
lamp filaments
inside the
reflector —
within .005" of
optimum.
Additionally,
SureFire
reflector
surfaces are
covered with
tiny ripples
that reflect
light at
slightly
different
angles,
smoothing out
beam
irregularities
and producing a
bright central
area surrounded
by a gradually
diminishing
corona. This
sort of beam is
perfect for
tactical
applications
because it
clearly
illuminates the
main object of
interest while
providing enough
light for the
observer's
peripheral
vision.
Tempered
Pyrex® Windows
With
Anti-Reflective
Coatings
On illumination
tools, the
transparent
covering that
protects the
reflector and
lamp from debris
and water is
called the
window (not
"lens").
SureFire
WeaponLight
windows — and
those of most
SureFire
flashlight
models — are
made of
tempered, coated
Pyrex glass, as
explained below.
Pyrex — Pyrex
glass is
essentially
ordinary glass
with boron
added, which
gives it two
desirable
properties: it
melts at a
higher
temperature and
has a much
smaller
coefficient of
expansion. In
illumination
tools, the
latter quality
helps resist
cracking when
one part of the
window is heated
more than
another, as when
an illumination
tool is turned
on, or when it
is suddenly
cooled, as when
splashed with
water.
Tempering —
After performing
any cutting,
shaping, and
drilling
required to
achieve its
final shape, a
piece of glass
is tempered by
heating it above
the annealing
point (about
1,100°F) and
then quickly
cooling it with
forced air. The
resulting
surface
compression
stresses give
the piece
several times
the structural
strength of
common
slow-cooled, or
annealed, glass.
Anti-reflective
Coating — The
windows of
SureFire
illumination
tools have a
thin coating of
material that
reduces
reflection
losses at the
glass surface,
which increases
the net lumen
output of the
WeaponLight or
flashlight.
|
|
Total
Internal
Reflection
Lenses
Many SureFire
illumination
tools use a
total internal
reflection (TIR)
lens that is
precision molded
from a special
cyclo-olefin
polymer. The
lens surrounds
the LED,
gathering
virtually all of
its light, which
it reflects and
refracts forward
in an
exceptionally
tight beam that
cannot be
duplicated with
a reflector.
Lithium
Batteries
As a commitment
to our customers
and products,
SureFire sells
its own brand of
quality 123-type
lithium
batteries at a
very low price.
Our WeaponLights
and
non-rechargeable
flashlights use
these lithium
batteries
because of their
advantages over
alkaline
batteries. These
advantages are:
Shelf Life —
Lithium
batteries can be
stored 10 years
and still supply
up to 90% of
their power.
Alkaline
batteries have a
significantly
shorter shelf
life.
Temperature
Tolerance —
Lithium
batteries
function over a
wide temperature
range (-60° to
80°C, or -76°F
to 176°F),
although power
is reduced at
the extremes. In
contrast,
alkaline
batteries
function poorly
below freezing
and at higher
temperatures.
The temperature
tolerance of
lithium
batteries also
benefits their
shelf life.
Storing alkaline
batteries at
higher
temperatures can
kill them in a
few months, but
lithium
batteries stored
for years at
similar
temperatures can
still function
effectively.SF
123A Lithium
Batteries
Power Density —
For a given size
(volume),
lithium
batteries
produce much
more power than
alkaline
batteries. For
example, given
same-sized
batteries and
the same power
load, it would
take about 2.5
alkaline
batteries to
match the power
output of one
lithium battery.
Weight — For a
given size
(volume) lithium
batteries weigh
about half as
much as alkaline
batteries. For
example, an
alkaline battery
the size of a
SureFire SF123
battery would
weigh about
twice as much.
Voltage —
Terminal voltage
for lithium
batteries is 3
volts compared
to 1.5 for
alkaline
batteries.
Voltage
Maintenance — A
lithium battery
maintains fairly
constant voltage
for up to 95% of
its life,
depending on
discharge rate.
At moderate to
high discharge
rates, alkaline
battery voltage
drops rapidly
due to internal
battery
resistance,
which wastes
power. The large
reaction area
provided by a
lithium
battery's
wound-plate
construction
provides very
low internal
resistance,
ideal for high
current loads.
Shock
Isolation and
Protection
Certain SureFire
illumination
tools, such as
our Special
Operations
Series
flashlights,
feature
shock-isolated
lamp assemblies.
This shock
isolation acts
much like the
suspension in an
automobile,
using springs
and dampers to
help prevent
external forces
from damaging
lamp parts —
particularly
filaments.
Additionally, a
machined-in
barrier prevents
batteries from
slamming forward
into the lamp
assembly. Note:
SureFire
illumination
tools that use
LED light
sources don't
need shock
isolation
because LEDs are
inherently
resistant to
shock and
vibration
damage.
For
exceptionally
hard-recoiling
weapons such as
12-gauge
shotguns and
larger caliber
rifles, where
batteries may be
damaged by
slamming
together,
SureFire
recommends our
special
shock-resistant
battery sticks.
These consist of
two, three, or
four batteries
assembled inside
a heat-shrunk
polymer sleeve,
with each
battery
physically
separated from
the others by a
load-bearing
fiber washer,
but electrically
connected by a
welded metal
conductor. For
low-recoiling
weapons, such as
5.56mm
self-loading
rifles, standard
SureFire SF123
batteries
function
perfectly.
|
|
Modularity
A fundamental
benefit for
users of
SureFire
illumination
tools is
modularity. This
means that many
components can
be used on
different
product models,
and that certain
product models
can be
reconfigured
with available
accessories to
meet changing
needs.
|
|
|