Blackled

Blackled is a term used in electronics to describe infrared-emitting light-emitting diodes (LEDs) whose encapsulation is intentionally tinted dark, giving the component a black or charcoal appearance even when powered. The tinting acts as a spectral filter, intended to suppress visible light while allowing infrared radiation to pass, typically in the common infrared wavelengths around 850 to 940 nanometers.

Construction and characteristics

The underlying LED die and circuitry are similar to standard infrared LEDs; the difference lies in the encapsulating material. The smoked or black epoxy or silicone filter reduces visible emission and can influence the perceived brightness by altering the optical path. Packages include through-hole and surface-mount variants, with typical forward voltages in the range of about 1.2 to 1.8 volts depending on the device. Beam patterns can be wide or focused, depending on the lens design.

Applications

Blackleds are used in applications where infrared emission needs to be less conspicuous to human observers. Common uses include remote-control transmitters, security and surveillance equipment, proximity and contactless sensing, and nighttime illumination for optics and cameras where visible light leakage would be undesirable.

Advantages and limitations

The primary advantage is reduced visible-light leakage, which can minimize glare and improve IR signal integrity in dark environments. Limitations may include slightly lower overall light output due to filtering, potential cost implications, and the need to verify compatibility with existing IR receivers, which rely on specific spectral sensitivities.

See also

Infrared LED; Remote control technology; Photonics.