Thermal Hand Held Imager DFOV

© Brooke Clarke 2015
Thermal Hand Held
          Imager DFOV

Background
Description
    Photos
Patents
Related
Links

Background 

Part of my interest in things optical and IR.  Note Wein's Displacement Law (Wiki) relates the peak wavelength emitted from a black body to it's temperature.
Thus the Sun's surface temperature of 5,500 K translates to a peak wavelength of 550 nm (where human eyes are most sensitive).  Also a human with a 98.6 def F body temperature has a peak emission at 10 um or 10,000 nm in the far infrared so thermal sensors typically work in a wavelength band centered on 10,000nm.

Description

Made by Thorn EMI labeled:
Imager Thermal Hand Held, DFOV (Dual Field of View), Ref: No D0024-5005, Unit No. 5C0/171410/3, Weight 3.9 Kg, Date 8/91.
Mod Record shows 1 & 2 marked.

A green house (Wiki) functions by letting light in but blocking long wavelength IR.  So glass blocks far infrared.  When a person is wearing glasses in a far IR photo they glasses will look black since they block the heat.  So glass lenses can not be used in far infrared optical systems.

The lenses are not glass (you can not see through them) and probably are made from either Germanium (Ge), Chalcogenide glass, Zinc Selenide (ZnSe) or Zinc Sulfide (ZnS).  I expect the lens material was chosen pass the wavelengths that the sensor responds to and block other wavelengths so maximize the signal to noise ratio.

The light output module is marked:  NSN 5855-99-967-3350, PL3 Y-34-4094-20 SK2, MR2-JH-2038.  It has two micro-D 15-pin connectors, one with male pins and one with female sockets.  I think there are two linear arrays of LEDs (Left and Right) inside, so the sensor may have a similar configuration.

The sensor has a micro-D female pin connector with 31 contacts.  So the sensor may have a two line configuration.

The mirror drive motor has three wires, red, black and brown, which is DC power an an index mark to synchronize the signal processing.  One of the small mirror arms has a small mirror that's sensed as the small mirrors go up and down.

    Photos


Fig 1  The objective lens is shiny black.
Thermal
                      Hand Held Imager DFOV
Fig 2 The rubber cup is missing on the eyepiece.  Open box is the battery compartment.
Thermal
                      Hand Held Imager DFOV
Fig 3 Contrast and brightness controls.
Thermal
                      Hand Held Imager DFOV
Fig 4 DFOV (Dual Field of View) switch for wide or narrow
Specialized mount for ???
Thermal
                      Hand Held Imager DFOV
Fig 5 Loop is to hold compressed (air?) bottle for cooling sensor.  The large black knob opens the jaws that hold the pressure tank and when closed push in the tank valve releasing the gas.
Thermal
                      Hand Held Imager DFOV
Fig 6 Cover removed
Cooled sensor tall cylinder at upper left of scanning plate
6-sided mirror motor below sensor
output light source to right of motor
Note the output light path is offset from the input path.
The input centerline matches the sensor scanning mirror
the output centerline matches the light source scanning mirror
Thermal
                      Hand Held Imager DFOV
Fig 7 Optics shown in narrow view mode
Cooled sensor at upper left and mirror motor to it's right.
Thermal
                      Hand Held Imager DFOV
Fig 8 Optics shown in narrow view mode.
Thermal
                      Hand Held Imager DFOV
Fig 9 Optics shown in wide view mode.
Thermal
                      Hand Held Imager DFOV
Fig 10 In wide vide mode the magnification lenses are out of path.
Thermal
                      Hand Held Imager DFOV
Fig 11  Inside cover external power input and fuze.
Thermal
                      Hand Held Imager DFOV
Fig 12 Cover by itself.
Thermal
                      Hand Held Imager DFOV
Fig 13  Electronics board has 14 daughter boards, maybe one for each brightness level.
Thermal
                      Hand Held Imager DFOV
Fig 14 Bottom of scanning plate with 6-sided spinning mirror and two small mirrors for input and output.  The small mirrors move up and down while the 6-sided mirror spins
Thermal
                      Hand Held Imager DFOV
Fig 15  Cooled input sensor at upper left and output light source at lower right.
Thermal
                      Hand Held Imager DFOV
Fig 16 Video of scanning mirror system YouTube

Fig 17 LED visible light output module.
Two rows (left and right)
Thermal
                      Hand Held Imager DFOV
Fig 18 Infrared (IR) two row cryogenic high pressure gas cooled sensor.  Plug covers pinch tube, probably for vacuum around front side of sensor.  Note input window looks like a mirror in visible light.
Thermal
                      Hand Held Imager DFOV Infrared (IR) two row
                      cryogenic high pressure gas cooled sensor.
Fig 19 Infrared (IR) two row cryogenic high pressure gas cooled sensor.  Fitting is for high pressure gas.
Thermal
                      Hand Held Imager DFOV
Fig 20 12 Volt specialized battery
Thermal Hand Held Imager DFOV


Patents

3728545 Infrared imaging apparatus, Honeywell Inc, Apr 17, 1973, 250/334, 348/E03.1 - early mirror scanning, not this device

Related

Optics - optical patents - optical bench
Flashlights
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M18 IR Binoculars - near IR not hot people or car engines
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MD-1 Automatic Astro Compass - also can see stars in the daytime
Astro-Compass for sighting Sun & stars
Periscopic Aircraft Sextant - Sun & stars
NextStar60 - cleaver microcontroller telescope using DC motors and shaft encoders
Orion - 9x63 binoculars - When the objective diameter (63 mm) is divided by the power (9X) if the exit pupil size (7 mm) is around 7 mm then the binocs are designed to be used with night adapted eyes, like for looking at the stars or to see things on the ground you could not see with bare eyes.  I once watched a dear swimming while being chased by a dog just after Sunset.  Although I could not see anything with my bare eyes, I could see fine with a pair of 7X50 binocs.  See my Binoculars page for more on star gazing binocs.
Celestron 8" Telescope with Equatorial wedge and tripod- This model has a clock drive but no computer control.  It's big and heavy, not something you pull out for a quick 5 minute look up.  Would be much better if used with a permanent pier.  It takes quite some time to do a Polar alignment, but when done you can find about anything just using the hour angle and declination scales.
Cloud Detection - as part of weather forecasting like used as part of an automated observatory - depends on far infrared (IR) sky brightness
Hughes Probe Eye infrared (heat) IR viewer - uses compressed gas for cooling
Shadow or Projection Clocks
PVS-4 Starlight Scope
PVS-5A Night Vision Goggles
UAS-4 Infrared Surveillance System, AN/AAS-14 Infrared Detecting Set, MK-898/AAS-14A Optical Filter Kit

Links

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Page created 29 April 2015