Generation – Night vision spotting scopes have been around for many years and are categorized by the term “generation.” Each substantial advancement in night vision technology establishes a new night vision scope generation. Here are some terms that you should understand:
Generation 0: The original night vision devices were created by the United States Army and utilized in World War II and the Korean War. These night vision devices use active or projected infrared light. An infrared illuminator is attached to the night vision devices and projects a beam of near-infrared light (similar to the beam of a normal flashlight, although invisible to the naked eye) which reflects off objects and bounces back to the lens of the night vision devices.
Generation 1: The next generation of night devices moved away from projected infrared light to use ambient light provided by the moon and stars to augment the normal amounts of reflected infrared light in the environment. Unfortunately, this also means that these night vision devices do not work well on cloudy or moonless nights. Since it uses the same image-intensifier tube technology as Generation 0, image distortion and short tube life are still a problem.
Generation 2: Major improvements were made to the image-intensifier tube which resulted in improved resolution, performance and reliable for these night vision devices. The biggest gain was in the ability to see in extremely low light conditions, such as a moonless night. This increased sensitivity is due to the addition of a micro-channel plate (MCP) to the image-intensifier tube. Since the MCP actually increases the number of electrons instead of just accelerating the original ones, the images are significantly less distorted and brighter than previous generation of night vision devices.
Generation 3: Even though there are no substantial technology change from Generation 2, these Generation 3 night vision devices have better resolution and sensitivity because the photocathode is manufactured using gallium arsenide, which greatly improves the efficiency of converting photons to electrons. Additionally, the MCP is coated with an ion barrier, which reduces the background noise and thereby enhancing the signal to noise ratio, resulting in a dramatic increase in the life of the image-intensifier tube.
Generation 4: Generally known as “filmless and gated” technology, this advancement in night vision technology provides a significant overall improvement in both low and high-level light environments. The removal of the ion barrier from the MCP, which was added in Generation 3 technology, actually allows more electrons to reach the amplification stage so that the images are significantly less distorted and brighter. The addition of an automatic gated power supply system allows the photocathode voltage to switch on and off rapidly, thereby enabling the night vision devices to instantly respond to a fluctuation in lighting conditions. This critical capability allows the night vision devices to immediately respond and compensate for any extreme changes in lighting environments. Generation 4 devices are typically reserved for professional use.