Night vision devices, as a product of the combination of optical and electronic technology, are widely used in various outdoor scenarios such as military reconnaissance, wilderness exploration, law enforcement and security, and wildlife observation. Many people have a common question when they first use night vision devices: why does the imaging of night vision devices mostly show green instead of other colors? In fact, this phenomenon is not accidental, but the result of multiple technological choices and physiological research working together. This article will analyze in depth why night vision devices are green from three perspectives: human visual characteristics, optoelectronic enhancement principles, and industry technical standards. Combining BINOCK's practical experience in optical equipment development, it will help readers fully understand this phenomenon.

The Relationship Between Human Visual Perception and Green Sensitivity

The human visual system has differential sensitivity to light of different wavelengths. According to the research of the International Commission on Illumination (CIE), the human eye mainly relies on visual rod cells for imaging under low light conditions, and rod cells are most sensitive to light sources with wavelengths between 500-550 nanometers, which corresponds to the green spectrum (Kalloniatis&Luu, 2007).

Compared to red or blue imaging, green is easier for the human eye to recognize and distinguish details in low light environments. This means that in the same environment, if the image is displayed in green, users can obtain higher resolution, faster response speed, and a longer comfortable viewing experience. In other words, green is not a random choice, but the best visual solution that is highly compatible with human physiological structure.

The Working Principle of Photoelectric Enhancement Tube and Green Fluorescent Screen

The core component of night vision goggles is the Image Enhancer Tube. Its basic working principle includes the following steps:

• Photon conversion into electrons: The faint light entering the night vision device first hits the photocathode and is converted into electrons. This is the step of converting photons into electrons.
• Electron multiplication: Electrons are multiplied in a microchannel plate (MCP) to form a sufficiently strong electron current.
• Electron impact on fluorescent screen: The enhanced electron flow hits the fluorescent screen (Phosphorus Screen) and is then converted into a visible light image.

In the selection of fluorescent screen materials, the optoelectronic industry generally uses P222 green fluorescent powder, whose emission peak falls exactly in the green light band that is most sensitive to the human eye. This not only ensures brightness and clarity, but also effectively reduces visual fatigue caused by long-term use. Therefore, the green screen is both the result of technology selection and the optimal solution for user experience.

The Balance Between Green and Visual Fatigue

From a long-term usage perspective, night vision devices are widely used in outdoor environments for continuous operations, such as military patrols, nighttime searches, or wildlife detection. If the image appears white or blue, although it may appear bright for a short period of time, it can easily lead to visual fatigue or even temporary blurred vision.

The green image provides a compromise solution:

• Adequate brightness, able to recognize details;
• Moderate contrast to avoid excessive glare;
• After prolonged use, the eyes can still maintain a high level of comfort.

Therefore, green is regarded as the best ergonomic choice for night vision equipment and has gradually become an international industry standard.

Technological Evolution and Establishment of Green Standards

In the development of night vision technology, green display was not initially adopted. The first generation of night vision devices in the 1940s had white gray imaging and limited resolution. With the emergence of second and third generation night vision devices, the performance of photoelectric enhancement tubes has been improved, and the introduction of green fluorescent screens has significantly improved imaging quality and human-machine adaptability.

At present, mainstream night vision devices generally use green imaging technology. Although White Phosphorus Technology (WPT) has emerged in recent years, with images closer to black and white photos, green remains a stable and reliable mainstream choice in most military and professional fields. BINOCK also uses green imaging in product development to ensure users receive clear and durable visual experiences in complex environments.

BINOCK's Professional Practice and Industry Applications

As a professional manufacturer of optical and night vision equipment, BINOCK deeply understands the scientific logic and user value behind the green imaging of night vision devices. In the actual research and development process, the company has made technological optimizations in the following areas:

• Fluorescent screen optimization: Select high-quality green fluorescent materials to ensure a balance between image brightness and contrast.
• Optical design: By using multi-layer coating technology to enhance light transmittance, green imaging becomes purer.
• Application scenario verification: Conduct extensive field testing in military exercises, field exploration, security duty and other scenarios to ensure the reliability and comfort of the equipment.

These experiences not only reflect BINOCK's research and development capabilities, but also provide practical references for the night vision equipment industry.

Why Night Vision are Green?

The green image of night vision goggles is not accidental, but the result of the combined effects of human visual characteristics, optoelectronic enhancement technology, and industry standards. Green imaging can maximize the sensitivity of the human eye in low light, while reducing visual fatigue and providing protection for long-term work.

From a scientific research perspective, this is the best practice at the intersection of optics and physiology; From an application perspective, green night vision images have become an international standard. As a professional enterprise in the industry, BINOCK will continue to explore and innovate in optical materials and imaging technology, committed to providing clearer, more reliable, and comfortable night vision solutions for global users.