Night vision goggles work by allowing the user to see in low-light conditions, and they achieve this through different methods. According to the provided reference, there are primarily three types:
Types of Night Vision Goggles
| Type | Description | Light Source |
|---|---|---|
| Image Intensifiers | Amplify existing ambient light, such as moonlight or starlight. | Existing |
| Thermal Imagers | Detect heat signatures and create an image based on temperature differences. | Emitted |
| Active Illumination | Create their own light, typically in the infrared spectrum, which is not visible to the naked eye. | Created |
Image Intensifiers
- How they work: These goggles collect the few photons of light available in low-light conditions and then amplify these photons.
- Process: The incoming light passes through a lens and hits a photo-cathode, which converts light photons into electrons. These electrons are then multiplied by an electron multiplier, and then the intensified electrons hit a phosphor screen which emits light creating the intensified image.
- Example: These are the most common type and are used in various applications such as military, law enforcement, and recreational uses.
Thermal Imagers
- How they work: These goggles detect infrared radiation (heat) emitted by objects.
- Process: The infrared radiation is focused onto an infrared detector. This detector creates a heat map based on temperature differences. The image is displayed on a screen.
- Example: Useful for detecting living beings or objects that have a heat signature, regardless of lighting conditions.
Active Illumination
- How they work: These goggles create their own light source, typically in the infrared range, that then is used to illuminate the environment.
- Process: They utilize an infrared light-emitting diode (LED) to flood the field of view with infrared light. The reflected infrared light is then detected by the goggle and creates an image.
- Example: Frequently used in very dark conditions or when other light sources aren't sufficient to use existing light.
Summary of Night Vision Goggles
In short, night vision goggles use several different technologies to make environments visible in low-light. They either amplify existing light, detect heat signatures, or create their own light, depending on their design and application.
