Cleanroom lights are special light fixtures that are specially designed so that they do not allow particulates to enter the cleanroom thru the light fixture. Depending on what class the cleanroom light fixture is being used for different features are added.

• Gasket seal on lens
• Gaskets on screws
• Stainless steel screws
• Air tight light fixture assembly
• Painted steel, painted aluminum, and stainless steel housings
• Tear drop light for 100% HEPA coverage ceilings
• Chemical resistance
• Impact resistant lenses
• Flat panel fixture
• Explosion proof fixture
• Colored film filters

The cleanroom industry shifted from fluorescent cleanroom light fixtures to LED (semiconductor Light Emitting Diode) cleanroom light fixtures around 2014.

LED cleanroom light fixtures advantages of fluorescent cleanroom light fixtures included:

• 50% lower energy consumption
• Introduce less heat into the cleanroom
• No longer need to replace light tubes
• Eliminated ballast as point of failure
• Equivalent cost by 2018
• Adjustable light strength

Cleanroom LED lights are available in different colors. 3500K, 4000K and 5000K are the most common colors available. The number refers to how warm or cool the color of the light appears.

• 3000K is warm yellow
• 4000K is neutral white
• 5000K is blue-white color. Small details are visible best at this wavelength. This is the most common LED color for cleanroom lights.

The intensity of cleanroom lights is measured in lumens or footcandles. Typical LED 2x4 flat panel lights deliver anywhere from 3000 to 5000 lumens. Depending upon the manufacturing or inspection process in cleanroom users typically specify sufficient lumens to achieve 75 to 100 foot candles per square foot.

Semiconductor manufacturers who use photolithography processes use special amber cleanroom lights to avoid wavelengths that can expose the photoresist. Historically, special amber tubes were placed over the fluorescent light bulbs to block the undesirable wavelengths.

Advances in LED technology have allowed manufacture of special LEDs that do not emit the undesirable wavelengths. This eliminates the need for the amber film on cleanroom lights but the film is still used on the windows of these cleanrooms. 

Summary: The cleanroom industry transitioned from fluorescent cleanroom lighting to LED cleanroom lighting around 2015. LED cleanroom lights used less power, dissipated less heat, and are similar cost. Important characteristics of LED cleanroom lights include: cleanroom classification, wavelength of light, and intensity.