DENO LED Lighting

Is violet-excited high CRI LED lighting better than a normal blue-chip white LED?

For colour accuracy, yes — for energy use, no. A violet-excited LED uses a roughly 405 nm die to pump a three-phosphor blend, so the 420-500 nm region a 450 nm blue chip leaves as a spike followed by a dip is filled in. You pay for it in efficacy: 80-110 lm/W instead of 130-150 lm/W. If the lighting is being judged by eye, choose violet; if the watts are being counted, a blue-pump Ra 95 board is still the better engineering answer.

How the two excitation architectures differ

A conventional white LED is a 450 nm blue die under a yellow YAG phosphor. Part of the blue passes through untouched, which is why the SPD shows a tall narrow spike at 450 nm followed by a dip around 480–500 nm before the broad phosphor hump. A violet-excited LED moves the pump down to roughly 405 nm, below the visible-sensitivity peak, and converts almost all of it through a three-phosphor blend of blue, green and red emitters.

The result is a smoother curve with no dominant spike, which is why violet-excited boards hold R9 above 90 without the red-phosphor overload that skews gamut on blue-pump designs. The cost is Stokes loss: converting 405 nm photons to 600 nm costs more energy than converting 450 nm photons, so efficacy lands 25–35% lower at the same drive current.

Choosing between them on a real project

Use violet excitation when the lighting is doing colour work — display cases, product photography, dermatology, premium retail — and when the connected load is small enough that the efficacy penalty is not a compliance issue. Use blue-pump Ra 95 for large connected loads, ErP-labelled products and anything where watts per metre must stay inside a project energy budget.

Both architectures are available on the same DENO FPCB stack-ups, in the same widths, densities and IP classes, so the decision is a die-and-phosphor choice rather than a different product family. Mixed schemes are common: violet-excited tape inside display joinery, blue-pump high-efficacy tape in the surrounding cove.

Industry references and standards

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