Learn About Starlight Technology
Night Vision Types
Night vision devices utilize three primary technologies: digital night vision, starlight technology, and thermal imaging. Both starlight technology and digital night vision amplify available light, while thermal imaging detects heat. These technologies produce different results and vary in design, cost, and image quality. This article focuses on starlight technology, the most prevalent type of night vision device. When we refer to "night vision" in this article, we mean starlight (image-enhancement) technology.
The night vision industry has seen significant growth over the past decade. Initially developed for military use, the technology has become increasingly popular and affordable for consumers. However, the most advanced designs are still restricted for export and only available within the US.
Definition (Starlight Technology)
Starlight technology, often synonymous with night vision, relies on amplifying available light. It does not function in complete darkness without a built-in infrared (IR) illuminator. The IR illuminator emits near-infrared light, invisible to the human eye but usable by the night vision device to illuminate the scene.
Night vision devices are categorized into three generations (Generation 1, 2, and 3), representing levels of design sophistication, image quality, cost, and capability. Although the basic components and technology remain largely consistent, the advancements in each generation significantly enhance performance.
A common misconception is that night vision devices function like binoculars by collecting light and focusing it directly into the eyes. Instead, they operate more like camcorders, converting available light into electrons, amplifying these electrons, and projecting them onto a screen that converts them back into a visible image viewed through an eyepiece.
Starlight Technology Design
Objective Lens: The front of the device features a conventional objective lens that captures ambient light and some near-infrared light. This lens focuses incoming light onto a photocathode at the front end of the image intensifier tube, which is adjustable for focusing at different distances, similar to binoculars.
Image-Intensifier Tube: The photocathode converts photons of light into electrons, which are then accelerated and amplified. In Generation 1 devices, this process can cause significant edge distortions. Starting with Generation 2, a microchannel plate (MCP) was introduced to address this issue. The MCP, a glass disk with millions of microscopic holes, multiplies and accelerates the electrons, greatly enhancing image quality.
Power Supply: This component powers the device and the display, sending pulses of electricity to accelerate the electrons within the image intensifier tube. A quiet buzz in Generation 1 units is normal and typically not a cause for concern.
Phosphorus Screen: Accelerated electrons strike a green phosphorus screen, converting them back into photons to create the final image. Green phosphorus is used because the human eye can discern more shades of green than any other color, which is why night vision images appear green.
Eyepiece: The eyepiece allows you to view the image projected onto the phosphorus screen. It is adjustable for focus, similar to a diopter adjustment on binoculars, ensuring sharp image clarity for different users.
Infrared (IR) Illuminator: This built-in feature emits a beam of near-infrared light, enabling the device to function in complete darkness by providing the necessary illumination.
Conclusion
Night vision devices encompass three main technologies: starlight technology, digital night vision, and thermal imaging. Starlight technology is the most popular among consumers due to its ability to amplify available light. These devices cannot function in total darkness without an IR illuminator. The basic components of starlight technology night vision devices include an objective lens, image-intensifier tube, phosphorus screen, eyepiece, and power supply, working together to enhance and project visible images in low-light conditions.
