Why don't we have a glass sheet or secondary lens under our LEDs like every other LED grow light?
We eliminated the glass for efficiency. Every time light transitions from one material to another, such as air to glass, some of the light is lost due to refraction. It does not matter how "clear" the materials are, if they have a different index of refraction, some of the light will be lost at the boundary between the two materials. For typical glass sheets, or acrylic or glass secondary lenses, this loss is 8-10% of the total light output even when completely clean. By using LEDs with glass primary lenses (which help to harvest more light from the LED's silicon), we have been able to eliminate secondary protective layers, giving our lights a 10% boost in efficiency.
It is important to note that we specially-treat our LEDs and LED boards to ensure the LEDs are protected and can be safely exposed. It is not safe- for you or the grow light- to remove the protective glass from other LED grow lights!