Infrared (IR) sunglasses are an emerging form of protective eyewear that protects eyes from the longer infrared wavelengths (IR) emitted by the sun. The long wavelengths of IR are not visible to the human eye, but humans can sense them by feeling heat from them.
In addition to blocking ultraviolet rays, infrared lenses also absorb harmful high-frequency blue light. They are available in a variety of styles to meet the needs of all people, including Marshall Protocol (MP) patients, who have a sensitive iris and need to wear sunglasses or prescription glasses to reduce their photosensitivity symptoms.
The lenses are made from chalcogenide glass, which is a glass that uses metals or semi-metals instead of silicon to make it more opaque to IR radiation. These chalcogenide glasses are a lot less expensive than other IR crystalline materials and can be moulded to create glasses with optical designs.
They are a bit more difficult to manufacture than standard glasses because they require a different moulding process, but they are gaining ground in the industry as a material solution for many new applications.
One example is a new type of night vision goggles that use infrared technology to help low-vision people navigate the world. The goggles feature tiny crystals that can receive and combine infrared rays from the environment with laser rays to “upconvert” them into a form that the eye can perceive.
Another infrared-sensitive application of chalcogenide glasses is thermal imaging, which involves measuring the temperature of objects using an infrared camera. This can be done by heating a glass rod preform up to the appropriate temperature, then drawing it into an optical fibre that is clad with a special IR-absorbing material.
These IR-absorbing materials are typically a mixture of chalcogens and semi-metals like niobium, tantalum, or tungsten. They are a good choice for a wide range of thermal imaging applications because they offer a higher degree of transparency and have a lower cost than crystalline materials such as single-crystal germanium.
They also have an impressive coefficient of thermal expansion, which means they expand or contract less than other common glasses when heated or cooled. This property makes them ideal for making the lenses that power IR cameras, which must be flexible enough to bend without breaking.
The glasses also have a unique ability to reflect the flash of a digital camera, keeping the computer from being able to detect the face in photos and videos taken with the camera. This is particularly useful for people who don’t want to take their picture with a flash, or those who are in a low-light situation.
There are some models of chalcogenide glasses that are available on the market, but the most popular are ones designed for arc welders. These glasses block IR radiation from the light coming off the arc welder and are a lot more durable than standard IR-blocking glasses. They are available in several shades and will suit a wide range of light-to-medium welding jobs.