Full Spectrum LEDs

Conventional white LEDs use a blue emitting semiconductor chip. Only part of its light is converted into green and red by a phosphor layer; the unconverted blue remains in the spectrum as a narrow-band peak.

The TRI-R technology used in SunLike LEDs works with a violet emitting chip instead. Its radiation is fully converted into red, green and blue by a dedicated phosphor mix.

• No unconverted chip emission in the spectrum and therefore no dominant blue peak
• No pronounced gap in the cyan range around 480 to 500 nm
• The pump chip emits in the short-wave visible range (violet); for UV-sensitive applications, the short-wave limit of the spectral distribution in the datasheet is what counts

The difference lies less in the Ra value itself than in the shape of the spectrum. Standard LEDs achieve their Ra value across eight unsaturated test colours. Saturated colours, above all R9 (strong red), often drop off considerably.

• Standard LED, Ra 80: highest efficacy, R9 frequently below 20, clearly visible blue peak
• High-CRI LED, Ra 90: more red phosphor, but the blue peak remains
• Full spectrum LED, Ra 95 to 97: gap-free spectrum, high R9 and TM-30 values

In practice this means that skin tones, textiles, paint finishes, food and metal surfaces can be assessed in their true colour rather than merely illuminated adequately.

Ra alone describes the quality of a full spectrum only incompletely. The following metrics are also relevant for the design:

• R9 – rendering of saturated red, decisive for skin, wood, food and textiles
• TM-30-20 with Rf and Rg – colour fidelity and colour saturation across 99 test colours instead of eight; full spectrum LEDs typically reach Rf values above 90 with Rg close to 100. The values for the specific variant are given in the datasheet.
• CQS – additionally evaluates colour saturation and observer preference
• Chromaticity spread in SDCM or MacAdam ellipses – SunLike COB are binned to 3-step; relevant as soon as several light emitting surfaces are visible side by side
• Correlated colour temperature – SunLike LEDs are available from 2700 K to 6500 K

A violet pump chip and full phosphor conversion mean a larger Stokes shift, that is more heat loss per lumen generated. Full spectrum LEDs therefore sit inherently below the luminous efficacy of high-efficiency Ra 80 types.

• 3030S-SunLike: approx. 104 to 139 lm/W
• 3030B-SunLike: approx. 95 to 111 lm/W
• MJT COB SunLike: approx. 81 to 109 lm/W

For the design this means: size the thermal management and the driver for the higher power demand if the same illuminance is to be achieved as with standard LEDs. Current values per part number are listed in the product table on this page.

Not across the board – they distribute the short-wave content differently. The narrow-band peak around 450 nm is absent because no unconverted chip emission remains in the spectrum. How much blue radiation is emitted in total still depends on colour temperature and illuminance.

• Short-wave light is scattered more strongly within the eye. An even spectrum therefore appears higher in contrast and less glaring.
• Photobiological safety, that is the blue light hazard, must always be assessed on the finished luminaire in accordance with EN/IEC 62471 – not on the basis of the LED technology alone.
• The CIE points out in its position statement that blue light hazard exposure limits are similar for white light sources at comparable colour temperature, incandescent lamps included.

Yes, with one important qualification: the melanopic effect follows the circadian rhythm through the sensitivity of the ipRGCs peaking around 490 nm and results from the entire spectrum. A missing blue peak alone does not make an LED melatonin-friendly.

• What matters is the melanopic daylight efficacy ratio (mel-DER) according to CIE S 026, not the course of individual peaks
• Time-of-day concepts require colour temperature and intensity control; SunLike LEDs cover 2700 K to 6500 K for this purpose
• Planning references are DIN SPEC 67600 and EN 12464-1

The actual advantage of the full spectrum is that the daylight-like spectral shape is retained across the entire colour temperature range.

Wherever colour carries information or light acts on people over long periods:

• Quality assurance and visual inspection – colour deviations, surface defects and material transitions become visible without spectral gaps
• Medical technology and life science – assessment of skin tones, tissue and samples
• Museums, retail and hospitality – exhibits, goods and food in their original colour
• Offices, educational facilities and interiors – even light over long periods of use
• Horticultural lighting – the PAR range from 400 to 700 nm is covered continuously; for pure yield optimisation, however, dedicated horticulture LEDs are superior in µmol/J

Full spectrum LEDs are less worthwhile wherever only lumens per watt and lumens per euro count, for example in street, high-bay or emergency lighting.

Three package families cover the majority of applications:

• 3030S-SunLike – mid-power SMD, 3 × 3 × 0.75 mm, variants around 0.2 W and 1 W, 120° beam angle, luminous efficacy up to approx. 139 lm/W
• 3030B-SunLike – SMD 3 × 3 × 0.6 mm with 3 V and 6 V variants (typically 65 mA and 150 mA respectively), 120° beam angle
• MJT COB SunLike – chip-on-board from 13.5 × 13.5 mm to 28 × 28 mm, 500 to over 4,000 lm, Vf approx. 35 V, 115° beam angle

As a rule of thumb: use mid-power LEDs for wide-area, low-glare lighting with many light points, and COB for directional lighting with reflector or lens optics, where a small, defined light emitting surface is required.

Full spectrum LEDs are used like high-quality standard LEDs, but because of their higher power dissipation per lumen they react more sensitively to tight thermal management.

• Junction temperature: Tj max. 125 °C; the design is based on the Tc measurement point defined in the datasheet, not on ambient temperature
• Thermal resistance: SunLike COB are around 0.7 K/W from junction to solder point – the heat sink determines luminous flux, chromaticity and lifetime
• Chromaticity stability: 3-step MacAdam ex works; drift over lifetime is phosphor-related and strongly temperature-dependent
• Lifetime: always derive L70 and L90 values from LM-80 measurement data with TM-21 extrapolation for the actual Tj and the actual drive current
• Driving: constant current operation; for dimming, PWM is preferable because the chromaticity remains stable across the dimming range