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Infrared Block - Visible Pass Filters
Filters for blocking select infrared wavelength ranges. IR blocking filters
are almost essential for colour imaging.
BP550 –
NIR-UV Block/Visible Pass - all color applications where filtering
is not provided with the camera's sensor
|
Model |
Transmission |
Features |
Suitable
for |
BP550 |
Passes 410-690nm
Reflects 350-400nm and 710-1550nm |
• Will effectively pass all visible light without
“discolouring” the image • Second surface is
anti-reflection coated for improved transmission and elimination of
glare and ghost images. • Heat-resistant coatings |
• All colour applications where filtering
is not provided with the camera's sensor • Use in full colour,
white light applications where either infrared or ultraviolet light
(or both) may be present |
The single substrate, hard-coated BP550 filter is designed for use
in full colour, white light applications where either infrared or
ultraviolet light (or both) may be present. Because of the steep
cut-off of these undesired wavelengths, a BP550 will effectively
pass all visible light without “discoloring” the image.
While colour rendition is greatly improved, this filter also serves
as a dust cover, protecting lens surfaces and internal threads.
BP550 reflects UV (below 400nm) and IR (now blocks 700-1550 nm)
wavelengths. The material does not auto-fluoresce but is somewhat
angle-of-incidence sensitive, exhibiting typical "blue-shifting";
it is designed for 0°-30° applications. Because it's a very
broad bandpass filter, the shifting at longer wavelengths usually
does not effect peak performance.
These filters features extended infrared rejection out to approximately
1550nm, resulting in significantly more heat removal in many applications
when compared to standard commercial “hot mirrors.”
The second surface is anti-reflection coated for improved transmission
and elimination of glare and ghost images.
The material used is a low-expansion glass and can withstand extremely
high temperatures. Coatings are known to be one of the most heat
resistant made anywhere and are used in the most demanding lighting
applications. The coating can also be supplied on fused quartz or
fused silica if extremely high temperatures are a problem. Again,
the substrate will fail before the coating does in such cases.
This filter is offered with a normal thickness of 2mm, but can
also be supplied 1mm thick. |
(left)
Straight digital colour image. (right) True visible colour is achieved
by eliminating the UV and IR wavelengths |
SP645 –
Mid-Red/NIR Dichrioc Block – best IR/mid-red block |
|
Model |
Transmission |
Features |
Suitable
for |
SP645 |
Passes 380-640nm
Reflects 650-1065nm |
•IR Blocking averages better than 99.99% from 675-900nm |
• Assembly immediately above a CCD or CMOS
• Blocking bright glow of hot metals, glass etc. |
The single substrate, hard-coated SP645 filter blocks much of the
red and near infrared (IR) portions of the spectrum. Substrate glass
is 1mm thick, as it is often the filter of choice for camera manufacturers
for assembly immediately above a CCD or CMOS sensor.
Depending on the spectral response of a given camera, many camera
manufacturers feel they achieve a much better colour balance when
they are able to not only block the IR, but much of the red portion
of the visible spectrum as well and this filter offers a superior
better-than-99.99% from 675-900nm. Additionally, the transition
at the cut-off point is particularly steep, making the SP645 filter
excellent value.
Certain machine vision filters can also be used to block the bright
glow of hot metals, glass and other material. Shortpass filters
allow light up to a specific wavelength to pass through while blocking
all light at higher wavelengths. This useful feature permits, for
example, the viewing of hot rolled steel to see certain temperature
areas while not blinding the system from the brighter, hotter areas. |
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SP675 – Deep Red/NIR Dichrioc Block – best IR/deep red
block |
|
Model |
Transmission |
Features |
Suitable
for |
SP675 |
• Passes 380-670nm
• Reflects 680-1080nm |
• Blocks some of the red and near-IR •
Steep cut-off point at transition |
• Assembling immediately above a CCD or CMOS
sensor |
The
single substrate, hard-coated SP675 filter blocks some of the
red and near infrared (IR) portions of the spectrum. Substrate
glass is 1mm thick, as it is often the filter of choice for camera
manufacturers for assembly immediately above a CCD or CMOS sensor.
IR blocking of the SP675 is superior – averaging better
than 99.99% from 700-925nm – and the transition at the cut-off
point is particularly steep providing both high-performance and
excellent value.
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SP700
– Hot Mirror/NIR Dichroic Block – standard IR block,
for use with monochrome cameras
|
Model |
Transmission |
Features |
Suitable
for |
SP700 |
•
Passes 410-690nm
• Reflects 350-400nm and 710-1550nm |
• Multi-layer, visible-optimized,
anti-reflection coating on the rear surface of the filter to improve
transmission and eliminate glare. • An "extended
hot mirror" that continues its IR blocking
capability out to 1550nm - |
• Broad visible wavelength transmission
and complete infrared blocking over the sensitivity range of all
monochrome cameras • Use as a heat-rejection filter |
The
single substrate, hard-coated SP700 is the filter normally recommended
for broad visible wavelength transmission and complete infrared
blocking over the sensitivity range of all monochrome cameras.
In fact, near-IR blocking extends much farther – to 1550nm
and beyond.
SP700 can be used as a heat-rejection filter. The substrate material
is Borofloat, a low-expansion glass similar to Pyrex. This material
comes in various thicknesses and is supplied with a multi-layer,
visible-optimized, anti-reflection coating on the rear surface
of the filter to improve transmission and eliminate glare.
The infrared spectrum is usually defined as starting at 700nm.
Depending on the spectral response of any given camera, some camera
manufacturers feel they achieve much better colour balance when
they are able to block ALL of the IR. Some of the deep red portion
of the visible spectrum is also affected. IR blocking over the
720-1075nm range is better than or equivalent to that of any standard
IR blocking filter in use by most camera manufacturers.
The SP700 continues its IR blocking capability out to 1550nm
- an "extended hot mirror" that most filter manufacturers
will not offer for camera applications, as a camera's sensor usually
has no sensitivity in this extended range. |
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SP730
– Hot Mirror/NIR Colourless Block – standard IR blocking,
for use with colour cameras
|
Model |
Transmission |
Features |
Suitable
for |
SP730 |
Passes 370-725nm
Reflects 735-1100nm |
• Excellent colour rendition due to no attenuation of the
visible spectrum • Small portion of near-IR and UV are
passed to insure that no deep blue or deep red wavelengths are sacrificed
|
• Standard IR blocking, for use
with colour cameras where the camera is not supplied with an infrared
blocking filter. • Blocking the bright glow of hot metals,
glass and other material |
The single substrate,
hard-coated SP730 filter is suggested for colour imaging applications
where the camera is not supplied with an infrared blocking filter.
Also known as a "crystal clear" hot mirror because
there is no attenuation of the visible spectrum, the results are
excellent color rendition. A very small portion of near-IR and
UV are passed to insure that no deep blue or deep red wavelengths
are sacrificed.
This dichroic filter is hard-coated on a low expansion glass,
therefore heat resistance is excellent.
The infrared spectrum is usually defined as starting at 700nm.
Depending on the spectral response of any given camera, some camera
manufacturers feel they achieve a much better colour balance when
they are able to pass ALL of the visible light to which their
colour camera is sensitive. The deep red portion of the visible
spectrum is essentially not affected, thus the 50% point for this
IR blocker is at 730nm. Infrared blocking over the 750-1100nm
range is better than or equivalent to that of any standard IR
blocking filter in use by most camera manufacturers. Average visible
transmission exceeds 95%.
Certain machine vision filters can also be used to block the
bright glow of hot metals, glass and other material. Shortpass
filters allow light up to a specific wavelength to pass through
while blocking all light at higher wavelengths. This useful feature
permits, for example, the viewing of hot rolled steel to see certain
temperature areas while not blinding the system from the brighter,
hotter areas.
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