Guide IR516FB Thermal Binoculars - Shattered lens - teardown & rebuild project

[Fraser]

I spotted a faulty Thermal ‘Binocular’, or more accurately, Bi-Ocular on eBay a while ago.
The seller stated that it was a Guide IR516B and I got interested as that model offers 800x600 pixel real thermal resolution. Sadly some investigation revealed that the unit is, in fact, the Guide IR516FB model and that additional ‘F’ makes all the difference ! The IR516FB has a resolution of 384x288 physical pixels, so not so interesting to me. The seller lowered the price but the unit remained unsold (not surprising really). I made a sensible (condition related) offer today and the unit is now on its way to me 

This is likely a project for when I have caught up on my backlog of other work but I thought I would share some pictures here to show the state of this unit and discuss options to return it to operation. It will come as no surprise that the whole lens assembly that sits in front of the microbolometer will need to be changed. The smashed objective element renders the current assembly scrap. This is a pity as this unit has a motorised auto focus capability and is fitted with a powerful lens.

I will document the teardown and plans for modifying this IR516FB unit here in case anyone else faces a similar smashed objective situation and wants to rebuild a unit into a working thermal camera. I am happy to discuss this unit and the options for repairing it if anyone wishes to post to this thread. It will likely end up as some sort of Frankenstein’s Monster 

The unit is equipped with a 384x288 25um pixel VOx microbolometer with 50fps refresh and it uses high resolution OLED eyepieces to display the imagery. Both picture capture and and video recording is supported. Not a bad unit for observation and security applications. The IR516A and B models were designed for military applications but I believe the FB model is a civilian variant.

Fraser

[lowimpedance]

Well Im all for 'Frankensteining' useful kit back to life, so I certainly would be interested in seeing the results. 
BTW, pardon the noob question, but whats the purpose of the capped port at the front ?

[Fraser]

The capped port on the front is the battery bay. The IR516FB unit uses Li-Ion batteries similar to those of Sony Camcorders.
Interestingly, the IR516A/B Military versions use two individual Li-Ion 18650 cells rather than a custom battery pack. This may be a military use requirement in order to ensure availability of replacement cells as the 18650 size are so common. The unit is waterproof to IP67 (1m submersion in water for 30 minutes) so the battery bay has a waterproof seal and large round bayonet mount cover.

[Fraser]

I attach the Guide IR516B model User Manual. This is the military variant with higher resolution, but otherwise very similar to the IR516FB model.
I could not find the user manual for the FB variant but my unit does come with a paper manual.

The IR516F model was available with two lens powers. The FA model has a 60mm lens and the FB model is equipped with an 80mm lens, both have motorized auto focus. It is a pity that my units 80mm lens is scrap, but then if it was not smashed, I could not have afforded to buy the unit 

Fraser

[RRtheone]

It certainly looks like a machine that is in "bad shape." I’ve seen this model for sale before—it goes for around $900-$1,000 （Guide IR516B）. Its large lens is very appealing and is probably its most valuable component, but unfortunately, the one on this unit is shattered.

Judging by the color of the shattered edge, the lens probably uses pure germanium.

[Fraser]

RRtheone,

Yes, this is the lower resolution FB model. I would have liked the 800x600 resolution of the IR516B but I got this unit for its scrap value as a project so I cannot complain. It is just something that caught my eye as a little project to enjoy working on The unit will never be as good as when it left the factory, but then it will not be used in a demanding role.

Fraser

[Fraser]

The Guide IR516FB arrived today and has been given an initial test and inspection.

I was pleased to find thathe unit is operational, with the main issue being the smashed Germanium lens. When buying a thermal camera of this genre with a smashed lens there is always the possibility that other serious faults exist within the unit. In this case it appears that I was fortunate as the menu system works fine and there is thermal sensitivity to my hand waving in front of the lens. 

The attached images show the condition in which the IR516FB was received. Considering its was likely made around 2014 it is in very good cosmetic condition with only the odd paint chip here and there. There is evidence of a fall event on the side of the lens barrel in the form of chipped paint, but no distortion of the aluminium alloy. the Germanium Objective has clearly been shattered when the unit was dropped onto gravel or rough terrain. There is even some mud in the lens aperture ! I do like it when the failure history of a unit can be established by physical evidence 

The remaining Germanium lens fragments needed to be removed as soon as possible so I used a lens retaining ring wrench to release the fragments from the outer edge of the lens. The Germanium lens was mounted using a silicone RTV but did not have a shock absorbing mounting system, hence the transmission of the shock wave from the outside of the lens barrel to the brittle Germanium lens. The lens retaining ring unscrewed without jamming so the lens barrel remains undistorted by the impact.

With regard to the original lens fitted to the IR516FB, it was a 80mm F0.8 that delivered a 6.87x5.15 degree FOV. Whilst this may be useful for long range observation, the minimum focus distance of around 20m would limit use for closer targets. With a powerful lens it can be difficult to hand hold the unit for a steady image. With this in mind, I am considering installing a lower power lens that is better suited to my needs. current options include a Raytheon 25mm F1.0 lens that was designed for the Raytheon 300D camera that had a 320x240 50um BST sensor array. Coupling this to the 384x288 25um pixel array would provide a decent FOV whilst maintaining some long range capability. I am also considering a 47mm lens that was designed for a 320x240 25um pixel microbolometer. The final decision on a replacement lens assembly will be made once I have studied the IR516FB design.

The case of the IR516FB is of all aluminium alloy construction and appears to be assembled through the front as there are screws located through the front panel. The investigation into the design and construction of the unit will follow as and when spare time permits.

Fraser

[Fraser]

The smashed Germanium objective lens.

[Fraser]

Removal of the Germanium fragments from the lens.

The second lens element is intact but has three maks on its surface. The IR516FB has motorized focus and I expected this lens element to move as the focus was changed. It did not appear to move during testing. There are other ways to set the focus in an optical system and this will be revealed once the unit is disassembled.

The recovered Germanium from the lens weighs 53g so the complete lens would likely have weighed approximately 200g. The Germanium may go to recycling as it has some residual value.

[Fraser]

Detail of the battery installation in the IR516FB

The battery pack is simple and basically just two 18650 cells in a plastic casing. The IR516FB battery has just two battery contacts, so there is no temperature monitoring.

[Fraser]

The IR516FB has been disassembled for an initial internal inspection.

What I found was a well made thermal imaging core mounted to the rear of an 80mm lens assembly, that is, in turn, mounted into the front panel using 6 screws. The lens is equipped with motorised focus that moves the rear element. Quality Swiss MAXON motors and gearboxes are used for the focus and FFC flag functions. End stop micro switches are visible on the barrel of the lens and these are activated by a brass spigot that is part of the rear lens holder. The unit does not test its end stop switches at boot, unlike my FLIR PM series, so it would be possible to delete the motorised focus function completely without causing a system error at boot. The aluminium lens barrel is effectively the chassis on which the thermal imaging core is mounted. Any replacement alternative lens would need to be grafted into that original lens barrel or a new core mounting arrangement created. The Microbolometer appears to be a ULIS PICO384.

An issue was discovered during the inspection. White silicone RTV was used on the connections of the focus end stop switches. This RTV had bridged from one switch to the FFC flag arm so would have been acting against movement of the arm since the unit was built. Whether this caused any issues for the previous owner is not known, but the Maxon motor associated with the FFC event would have had to overcome that additional physical resistance to rotation. The silicone RTV bridge has now been removed.   

The wiring inside the IR516FB is functional, but not very neat or properly managed. Loose cable runs hang around inside the casing and this is not as would be found in a military product where cables are well managed to avoid chafing or flex induced fatigue.

The two eyepieces have individual OLED panels and driver PCB's There is no inter-pupil distance adjustment on this unit. A diopter adjuster is present on the eyepieces.

The casing has a sensor and red window adjacent to the left eyepiece. the purpose of this sensor is not currently known, but it could be the face proximity detector that is mentioned in the IR516B user manual. If it is, it is not currently activated as the eyepieces are on all of the time, and not just when the users face is present at the eyepieces. I shall investigate this further at a later date.

I see no reason why a new, alternative, lens cannot be grafted into the IR516FB, but it will take some planning and work to achieve a useable system. This is a long term project to keep me entertained so I am in no great hurry.

Fraser

[Fraser]

Disassembly continued..... The thermal imaging core, motors and focus end stop switches.

The Microbolometer appears to be a ULIS PICO384.

[Fraser]

Whist looking at the photos that I have just uploaded, I noticed another quality control issue with the unit.

A core related ribbon cable has been broken out into individual conductors. One of the conductors is exposed and could short to metal parts with unknown consequences. This will be fixed to avoid such a risk. The adapted grey ribbon cable is anything but elegant and a better cabling solution should have been devised.

[Fraser]

Worthy of note when looking at the IR516 thermal scope/camera design is the fixed distance between the two eyepieces. There is no adjustment possible for the users specific inter-pupillary distance. This is a significant oversight on the part of the designer as it forces the users eyes to adjust to the fixed inter-pupillary distance and can cause eye muscle strain. In use I found that I initially saw two overlapping eyepiece images that gradually converged into a single image as my eyes and brain dealt with the inter-pupillary distance mismatch. More modern designs of binoculars//bi-ocular thermal imaging systems have adjustable eyepiece inter-pupillary distance. I may modify the IR516FB to offer some adjustment of the distance between the eyepieces.

I attach pictures of the IR516 with its fixed eyepiece design, and the newer TN630 that has adjustable eyepiece inter-pupillary distance.