Infrared scopes, also known as thermal scopes, work by detecting infrared radiation (heat) emitted by objects and converting that information into a visible image on a display. Here's a breakdown of the process:
1. Infrared Radiation Detection:
- All objects above absolute zero emit infrared radiation. The hotter an object, the more infrared radiation it emits.
- The scope's objective lens, made of materials like germanium or silicon, focuses the incoming infrared radiation onto a thermal sensor. Unlike regular glass, these materials are transparent to infrared light.
2. Thermal Sensor:
- The thermal sensor, or microbolometer, is a grid of tiny, heat-sensitive resistors (bolometers).
- Each bolometer absorbs the infrared radiation focused on it, causing its temperature to rise.
- The change in temperature alters the electrical resistance of the bolometer.
3. Signal Processing:
- The changes in resistance of each bolometer are measured and converted into electrical signals.
- These signals are then processed by the scope's internal electronics, creating a temperature map of the scene.
4. Image Display:
- The processed signal is sent to a digital display, usually a small LCD or OLED screen within the scope.
- The display assigns different colors or shades of gray to represent different temperature levels. Hotter objects are typically shown in brighter colors, while cooler objects appear darker. This creates a visual representation of the heat signatures in the scene.
5. Reticle Overlay and User Adjustments:
- A reticle (crosshair) is electronically overlaid onto the thermal image, allowing the user to aim.
- Users can typically adjust settings like brightness, contrast, polarity (white-hot or black-hot), and zoom to optimize the image for different environmental conditions and target distances.
In Summary: Thermal scopes detect heat, translate it into a visual image, and overlay a reticle to allow for aiming in low-light or no-light conditions.
