Night Vision and Thermal Systems

Infrared LED

An infrared light-emitting diode (infrared LED) is a small device used primarily on electronics which emits light that is on a different wavelength, lower than the visible light. A regular LED is commonly referred to as a small indicator light, which functions as a semi-conductor type of diode. Infrared LED also somehow works in this manner, as well as minimal data transfer between electronic devices (e.g., remote control devices), acts as illuminators for night vision equipments, and several more purposes. From the edge of red wavelength, the infrared wavelength flows around 0.74 micrometers to an approximate standard of 300 micrometers.

The International Commission on Illumination (CIE) recommended the following band classifications, namely: a) Near-Infrared (NIR, IR-A DIN): ranging from 0.75-1.4 μm, is typically used for fiber optics technology and night vision devices; b) Short-wavelength Infrared (SWIR, IR-B DIN): ranging from 1.4-3 μm, is apt for longer distances of telecommunications; c) Mid-wavelenght Infrared (MWIR, IR-C DIN): ranging from 3-8 μm, is used on guided missile technology, working on a 3-5 μm working window of control for seeking heat signatures on target subjects, particularly the jet engine exhaust plume; d) Long-wavelength Infrared (LWIR, IR-C DIN): ranging from 8-15 μm, is identified as the wavelength zone for thermal imaging; and e) Far Infrared (FIR): ranging from 15-1,000 μm, generally used for far-infrared lasers.

On night vision devices released in the market, the Gen 1 rely greatly on ambient lighting instead of infrared stretching from 780nm and 808nm LEDs, but they are large devices which make it difficult to mobilize. The Gen 2 showcases the improved image-intensifier tubes for brighter image resolution, which functions at around 850nm and above. Gen 3 devices uses the photocathode made from gallium arsenide, thus, further improving image quality and works around 940nm.

Because of its capability, IR LEDs had been used for security cameras, for low lighting condition needs. This technological innovation is useful for simple and complex surveillance system and operations, behavioral activities of the environment and people. Watching over from a distance, the Closed-Circuit Television (CCTV) system is universally used, though the technology used varies from model and make. IR cameras are often connection to an analog or digital recording device, Internet Protocol (IP) network technology, and human physical monitoring.

Aside from structure or building surveillance which require a stable mount for the cameras, there were hand held IR cameras released for the sake of portability and mobilization, hence, making it lightweight and less bulky.

Many night vision devices employ infrared illuminators for further visual enhancing especially in low lighting conditions. This has proven to be functional among military operations such as recons and covert operations, as well as law enforcement missions. Its role is to provide proper illumination and acquisition of human and structural targets with varying levels of capacity. In some devices, the process starts from the conversion of ambient light photons into electrons which are further improved by chemical and electrical enhancements, then converted back to the visible light wavelength for human visuals.

The longer the wavelength means lesser visibility of the red glow according to the color spectrum. The red hue ranges around 400-484 THz or 620-750 nm while the infrared wavelength is around 100-430 THz or 700-1mm. This means that there infrared runs at the border of the red wavelength.

This technology somehow poses a health hazard to the eyes due to particular industrial high heat settings. Since infrared is “invisible” to human vision, Infrared protection eye gears should be worn at all times when dealing with this.

Categorised as: Night Vision

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