freedom in lighting design by tuning the cct with leds, lps 2015, bregenz

The Degrees of Freedom Provided by Modern Methods to Tune CCT and LED WavelengthsWojtek CieplikLED Engin

5th International LED professional Symposium +ExpoLpS 2015 | Sept 22-24, 2015 | Bregenz

Paradigm shift in the lighting industryHuman Centric LightingSmart LightingA smart light engine for human centric lighting designFuture challenges

Outline

Was L&B 2014 a turning point?

it appears that way

Fundamentals of life

as long as we are on earth, some things remain unchanged

MONEY SEXPOWER

AND…

NATURAL LIGHT

Fundamentals of life

as long as we are on earth, some things remain unchanged

to mimic natural light and (or)…

The challenge for the artificial light

Colour sensitive cones = 64% are Red-sensitive, 32% Green and 2% Blue

Human eyes capture radiation through rods and cones and dissect it into 3 components

The challenge for the artificial light

…to make our eye respond to it that way

HCL

Promoting people’s

well-being

People’s concentration,

efficiency, safety

Healing processes

Still not in focus

Challenge for LED

technology

To become multibillion business

Human Centric Lighting = focus on user

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10Dynamic CCT

Colour rendering

Colourconsistency

# of colours

Beam angle

Frequency

DriverLumen output

Control protocol

Smart (sensorics)

Form factor

System costs

Simplicity

HCL (general) Museum Retail

Focus on user Focus on quality

quality depends on the application

Smart lighting demands system approach

all the elements needed maximize user experience

Hardware & software Human factor

Tunable white

User interface

Sensors for touch behaviour & activity

recognition

Light management system

Impact experienced by the users

light source & components

Integrated solutions

Light source Beam quality colour qualityStability

Shadow quality

Directional/non-directional

Array of emitters(low cost, mid power)

Poor colour mixing & tuning

CRI, R9Not so stable

Worst >60⁰, non-directional more glare

COB Poor colour mixing & tuning, limited colour positions

CRI, R9, 2-channelsStable

Good 25~60⁰ reflectors/TIR lens, less glare

Single multi-die emitter

Superior in-source colour mixing, tuning, & optimized colour positions

CRI, R9, multi-wavelength spectrumVery stable

Best 10⁰~55⁰ TIR lensless glare

Choosing optimal light source

according to quality of the beam, colour and shadow

Choosing the optimal light source

according to shadow quality

Choosing optimal white light

following the sun

colour characteristics of artificial sources vary

• White light of equal appearance can be created with different Spectral Power Distributions (SPDs)

• This chart shows the SPDs for four different light sources, all producing 2700K white light with a CRI > 80

Mimic sun: mission impossible?

PHOSPHOR-CONVERTED (Pc) LEDPhosphors convert blue or near-UV light from the LED into white light

COLOUR-MIXED LEDMixing the proper amount of light from red, green and blueLEDs yields white light

HYBRID METHOD LEDA hybrid approach uses both phosphor-converted anddiscrete monochromatic LEDs

Pc vs. RGB vs. hybrid

demands measures

• Colour space map with black body curve – Plank’s Law

• Colour space map with MacAdam’s Ellipses

Benchmarking artificial to natural light

• Fixed White: Blue-Yellow

• Fixed/Dynamic White: RGB

• Linear Dynamic White: CW-WW

• Hybrid Dynamic White: R-mG-CW

can there be only one?

Choosing optimal multi-colour set-up

tunable white light engine, here with 2 features

Hybrid R-mG-CW enables

CRI throughout the CCT range

R in hybrid R-mG-CW enhances

Beware!

limitations of existing colour metrics may be confusing

Source: www.ssl.energy.gov

Beware!


Source: Smithsonian American Art Museum

Market needs colour quality!


Source: Xicato

Calibration

is the key to colour consistency overtime and temperature

Colour consistency for 40 units <2 SDCM in Warm Dim mode

Colour consistency for 40 units <2 SDCM in CCT Tune mode

Warm dimming

brings the emotion and sense of nature

Software solution helps to overcome driver limitations

Noise- and flicker-free Increased no of steps per channel

Deep dimming (<1%) Variable frequency

Increase refresh period as level decrease. Effectively decrease relative min turn off time

Refresh interval randomization Provides better colour mixing

Are we there yet?

no!

Control protocol (0-10V, DMX, DALI, Zigbee, …) Driver (AC / DC, 24/48V, frequency, flicker) Firmware, software Heat management Complexity of the system but simplicity for the user (UX) Total system cost

variety of decisions to make when designing user-driven lighting system is significant

HCL

More continuous

SPD(mimic sun)

Freedom of wavelengths

(460-480nm, UV)

>3 individually addressable

channels

Increased CCT tuning

range (2700-6500K)

More beam angles

(narrower, wider)

HCL is defining LED product roadmaps

LZ7 platform 7x1mm2 dieson AlO (white) 7x7mm substrate

flat lens7 individually addressable coloursemitter-only or emitter-on-board

LED Engin’s roadmap




Designed primarily for versatile wash lights with zoom optics (ENTERTAINMENT)R-G-B-CW-A-C-UV

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Red Green Blue White Amber Cyan UV




Designed primarily for versatile wash lights with zoom optics (ENTERTAINMENT)R-G-B-CW-A-C-UV

A possible die design for HCL could be: R-mG-B(460-480nm)-CW-WW-UV-x

Will this be the next generation platform for HCL?

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Red Green Blue White Amber Cyan UV

Human Centric Lighting will keep enabling crossover of technology, science & art

thank you

Back-up

Paradigm shift in lighting

according to value metrics

` Energy colour quality& stability

Glare(UGR)

Useful light& cost

UX

Energy efficiency(low & mid power emitters)

lm/W CRI, R9Not stable CCTMultiple shadows

Large LESGlare

lux/W lowlux/$ low

Not good

Warm dim/CCT tuning(single multi-die emitter)

lux/W CRI, R9, COAStable CCTNatural shadows

Small LES TIR/ReflectorLess glare

lux/W highlux/$ high

Good

Human centric/connectivity

Sensors, controls, VLC

Natural light like Not visible Very good

Development

of 3 channels is closer to natural light than CW-WW

Spectral power distribution (SPD)

Optics

soul of the dynamic white solution

TIR lenses enable many functions color mixing, also in direct beam define the beam (cut) define shadow quality prevent glare

Promoting people’s

well-being

Design

Materials / Haptics

Sound

Air quality & tempErgonomics

Proximity to nature

LIGHT

Well-being depends on…

Healing processes

Patients are

scared

Daylightis

important

Doctors are

people

Cost isn’teverything

Circadianrhythm

Use the best tech

Designing lighting for healthcare*

* Healthcare Lighting Forum, LuxReview2014 Vol 3, Issue 3

Calibration

is the key to colour consistency overtime

Δu’v’ = 0.007 EnergyStar limit

Calibration

is the key to colour consistency overtime

Background Dimming level and min switching time limited by driver hardware

100~ 200 steps are common per channel Limited per channel minimum to 0.5-1%

Different color ratio will limit the lowest dimming level to ~5%

Solution Enhance lowest dimming level via software Applying algorithms to achieve <1% deep dimming

0.5% deep dimming e-flickering-free and noise-free 20kHz refresh rate Lowest dimming level at timestamp 4:30

Software solution (<1%) Dithering

Turn on and off bit pattern to increase level of dimming Variable frequency

Increase refresh period as level decease. Effectively decease relative min turn off time

Refresh interval randomization Provide better color mixing Decease need of higher frequency

Dimming

Challenges for the industry

Will CRI prevail? Other solutions like GAI or CQS are available but still lack industry agreement

Warranty Industry finds it difficult to make a box of circuitry last five years (see cars, aircrafts)

Dimming compatibility wall dimmer vs. transformer vs. fixture

Blue light discussion It helps to stay alert but can damage retinas

Control protocols on debate Which protocol will be the way for the industry? DALI, DMX (-RDM), Zigbee, EnOcean, KNX, 0-10V, Bluetooth, custom/bespoke?

Low cost integrated solution In-package driver, no cables, connectors

THANK YOU

Wojtek CieplikRegional Sales Director

Lighting OEMs & SpecifiersLED Engin Inc.

[email protected]

mailto:[email protected]

freedom in lighting design by tuning the cct with leds, lps 2015, bregenz

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