Conventional red light, such as lights found on traffic signaling systems, and infrared light, a non-visible beam commonly found in security cameras, are often mixed up by consumers. To shine light on this issue, the lights are not the same and come with contrasting applications and builds.
Visibility and Wavelengths
The main difference between red light and infrared light is visibility. Red light can be seen and is easily distinguishable – like blue or orange light. An example of this is a red beam emitted by a forklift LED safety light. The compact lamp creates a clear and visible red boundary zone around the vehicle, which warns nearby pedestrians and workers about ongoing forklift operations in the area.
By comparison, infrared light is non-visible. One cannot detect infrared beams without special equipment. An example of a device that incorporates infrared lamps is a security camera. Infrared light is used for night-vision capabilities, allowing operators to monitor locations discreetly after sunset, without illuminating the area.
On a visible spectrum scale, red light can be found near infrared, at a range of 620 nm to 750 nm. Infrared ranges between 700 nm to 1mm, which is the start of the non-visible beams on the chart. Microwaves (1mm to 1 meter) and radio waves (1 meter to 100,000 km) come after infrared and are also non-visible.
Generating Red and Infrared Light
Traditionally, red light, as well as other light colors, is generated using films or colored lenses. In the era of incandescent lighting, this was a common practice. What you get is a white light that is ‘filtered’ to emit a red light. Although the method works, there are some drawbacks with the technique. Breaking the lens or ripping the film causes inconsistencies in the colored light beam being projected.
LEDs are capable of generating red light without a colored lens or film. Instead, the diode is colored, which results in a more saturated, full red color. LED lights with colored features typically incorporate red, green and blue colors (RGB) in the module. Mixtures of the colors can be leveraged to create numerous combinations. For operators, this method of generating red light is better, since it offers more control of the exact color during projection.
When generating infrared light using LEDs, the unit must be capable of operating within the infrared spectrum. An advantage of infrared LEDs is their solid-state builds, allowing the luminaries to be used in rugged environments with minimal risk of failure due to tampering or rough contact.
Uses and Applications
Because the lights are composed differently, their applications vary as well. Red lights are applicable to signaling in industrial facilities, such as warehouses and delivery bays. On a mainstream level, people may improve the creation and release of melatonin through exposure to red light, resulting in comfortable and consistent sleeping patterns. This technique is very helpful for individuals suffering from jetlag or work night shifts. Blue light has an opposite effect on people, causing individuals to stay awake and alert during exposure.
Plant growth stimulation in indoor commercial farms may also use red light to promote photosynthesis. A combination of red and blue light is required for balanced growth, with a ratio of 95 percent red light and five percent blue light (for lettuce, based on a study from NASA).
Red light is applicable to hunting nocturnal animals, such as coyote. In application, a hunter may use a red LED spotlight to scan the area for creatures in the field. Because red light is considerably dimmer, compared to white light, the animals are less likely to get spooked. A low to moderate light setting is recommended to prevent spooking.
On the other hand, infrared light is useful for nighttime monitoring (as mentioned earlier). This type of light is also utilized in automatic number plate recognition protocols at tollway systems, which allows operators to streamline the detection of license plates during collection. Moreover, infrared illuminators support vehicle counting and classification processes for transportation groups worldwide. In the field of biometrics, infrared may be applied to boost the accurateness of facial recognition devices.
Other uses for infrared light includes the following:
- Thermography: monitoring temperatures in real-time from a safe distance
- Heat signature tracking: military, missile guidance systems
- Artifact analysis and verification: detecting inconsistencies in paintings/pottery
- Weather tracking: overseeing the development of cloud formations