Thermal Devices PARTS & TYPES

Thermal Devices PARTS & TYPES

Published by Bastian Green & Damon Loats - on 18th Aug 2022

What are the BASIC PARTS of a Thermal?

We start with a rare earth metal (Germanium) objective lens which goes through to a thermal imaging sensor. This is connected to a CPU and within that, the algorithms that take that radiation information that the sensor picks up, translates that into what we can see as an image on a display. Thermal images also have varying power supplies. These can be an internal battery or removable batteries.  Alternatively, a lot of devices will accept an external power supply.

It is important to note that the resolution on the display is based on the resolution of the sensor.  If the sensor can record 640 pixels, then that resolution is projected on the display. However, the displays actually have a HD resolution, so the 640 pixel from the sensor is "blown up" on the display. In other words, the resolution of the display is irrelevant. What matters is the resolution of the sensor, so don’t be fooled by some of the marketing guys who say, “It has a HD display,” or “It has a 4K display”. It doesn’t matter because the image is still generated and processed by the sensor, and therefore the sensor is the limiting unit in your thermal device.

What type of thermals are available?

Handhelds (Monocular& Binocular)

Thermal handheld devices are categorised into monocular and binocular. A monocular is used by only one eye. One disadvantage of a monocular is looking at a bright display at night time, you will night blind that eye. A set of binoculars still only have one objective lens, and the image is displayed through two identical displays for both eyes, but still you are unable to judge distance at night time when looking through a digital binocular device. Some customers struggle just looking through a monocular at night, because you get night blinded in the one eye. We suggest using binoculars but then you can be night blinded in both eyes, which can be an issue and restrict your movement around at night time as opposed to still using a monocular and being able to use one eye to move around. Thermal monoculars are more common and cost effective as opposed to thermal binoculars because there are only a few manufacturers that make binoculars to start with and the cost is much higher, because there are so many parts that need to be duplicated in binoculars.

Riflescopes (Ring & Rail Mounted Styles)

Thermal Riflescopes come in different designs. There is the riflescope looking design which uses traditional scope rings to be mounted to your firearm. Or the traditional rail mounted design where a mount that sits onto a Weaver or Picatinny rail gets attached on the bottom and then attached to your firearm. Some thermals come with a laser range finding unit, and can also have the exact same unit without a laser range finder.  Some units can have laser rangefinders attached later on, like the InfiRay RICO range of riflescopes.

Clip-Ons (Front Attachments)

Thermal clip-ons are thermal devices that attach to the front of your scope. These devices can only attach to a dayscope by using an adapter. These adapters have to be bought for each individual scope you have (see Precise Hunting). So if you have the same exact scope, you can use the same adapter. That said, there are some adapters which work on various different size objective lenses of your day scope (see PSP adapters). However these are very likely to lose zero over time, and are also not as accurate as dedicated adapters for specific sizes. How does it work? You just screw the adapter onto the end of your thermal device, and then attach the adapter to your day scope. You line up your thermal so it is horizontally aligned and then you use (in this case a lever) to tighten it up. When you look through your day scope, you’ll be able to see the image projected by the thermal into the objective lens of your day scope, therefore turning your day scope into a thermal device.

Head Mounted (NVG)

We also have head-mounted thermal devices which through an NVG mount can connect to headgear or a tactical style helmet and be brought down over your eyes and sometimes even use two. The advantage of head mounted thermals is that you have your hands free and most of the time they have a base magnification of 1x, which is exactly like your eyes, so you are able to walk around at night with those devices, therefore covering more land in less time.

Vehicle Mounted (Stabilised vs Non-Stabilised)

You can get a dedicated unit which can be mounted using a magnetic base or suction cups temporarily to the top, or part of a moving vehicle, or permanently using a fixed base and is used primarily as a scanning thermal. Vehicle mounted thermals use WiFi or cables to project the image that they capture onto a display in your vehicle. (see Night Ride Scout models)

Through either a tablet, or a remote control device, you’ll be able to manually control the unit, or have it scan or even in some cases these units have optical lasers that you can see and therefore know which direction the thermal is looking. Some actually have laser range finders built in as well which will then give you the distance to whatever animal, or target, or object you decide to point it at & measure.

There are two different types of vehicle mounted thermals. Ones that are stabilised and ones that aren’t stabilised. The stabilised image while the vehicle is moving around rough terrain, you can still scan and see a nice, still, clear image on the display. Whereas a non-stabilised device you would normally have to stop and scan the actual area and not be doing that while you’re travelling. So in essence, a stabilised device is going to save you time and effectively, money if you’re a contractor, as you cover much more land over the same period of time