Spectral Power Distribution (SPD) of Household LEDs: The 450nm Blue Spike

True 'white' LEDs do not exist in semiconductor physics. To produce white illumination economically, manufacturers utilize Phosphor-Converted LEDs (pc-LEDs):

1. A semiconductor diode chip composed of Indium Gallium Nitride (InGaN) emits a narrow, extraordinarily intense monochromatic beam of high-energy blue photons at $\lambda = 450\text{--}455\ \text{nm}$.
2. The chip is encapsulated in epoxy mixed with a Cerium-doped Yttrium Aluminum Garnet (YAG:Ce) phosphor.
3. The phosphor absorbs roughly 60% of the blue photons and re-emits them via Stokes-shift fluorescence as a broad, low-energy yellow-green band (500–650 nm).

When the unabsorbed 450 nm blue light mixes with the secondary yellow fluorescence, the human eye perceives 'white' light. However, an optical spectroradiometer reveals a massive, unnatural 'Blue Cyanosis Spike' towering over the rest of the spectrum.

The ratio of blue spike to broad phosphor emission determines the bulb's Correlated Color Temperature (CCT):

• 2,700K (Warm White): Thicker phosphor layer; blue spike is attenuated, though still present. Best for evening bedrooms.
• 4,000K (Neutral Office White): Moderate blue spike; widely installed in modern commercial workplaces.
• 6,500K (Cool Daylight White, ubiquitous in Indian homes & offices): Minimal phosphor coating; the 450 nm blue spike is massive and punishing, saturating human ipRGCs with daytime wakefulness signals well into the night.

Natural sunlight and incandescent bulbs provide continuous photobiomodulative near-infrared (NIR, 700–900 nm) photons that energize retinal mitochondrial repair enzymes. Modern LEDs emit 0% near-infrared light. The eye receives pure high-energy visible stimulation with zero biological recovery photons.

Wearing ELLASUV BluePro Spectacles indoors attenuates the 450nm artificial spike, softening the harsh LED spectrum to mimic comfortable natural daylight.