Presentation given at the EUROLED conference in February 2013

A Lighting Designers view on LED Technology

In the beginning was the FLAME …

which came at quite a price …

It began simply enough

gained a solid

reputation

threatened a

species

became draught-proofed

achieved a brighter future

got turned upside-down in

the process

But it was still

just a flame in a bulb

And then there was the lightning …

The long light had arrived

With all kinds of results

and scale

and story-telling

Until energy started costing

more than was

comfortable

Meanwhile, there were new frontiers …

The point source had been a dream

Because designers wanted CONTRO

L

and once that idea took hold …

it took on enormous

influence …

… for good or ill

Until …

and this …

became this …

Bulbs:

Ref

lect

or

(light)(heat)

LEDs: 90°-140° viewing angle

(light)

(heat)

(light)

The fundamental differences:

– Directionality of generated light

•Omni-directional vs. directional

– Means of evacuating generated heat

•Convection vs. conduction

LED technology introduced us to a whole new way of looking at our old familiar friends …

But which also introduced us to a whole new world of lighting opportunities …

So … what DO we want from the LED?

Much of what the lighting designer wants is

consistency across all of the available

sources ….

But can the LED deliver on

Much of what the lighting designer wants is

consistency across all of the available

sources ….

But can the LED deliver on

Energy efficiency ?

Much of what the lighting designer wants is

consistency across all of the available

sources ….

But can the LED deliver on

Energy efficiency ?

Long life expectancy ?

Much of what the lighting designer wants is

consistency across all of the available

sources ….

But can the LED deliver on

Energy efficiency ?

Long life expectancy ?

Colour quality ?

Much of what the lighting designer wants is

consistency across all of the available

sources ….

But can the LED deliver on

Energy efficiency ?

Long life expectancy ?

Colour quality ?

Cost effectiveness ?

Much of what the lighting designer wants is

consistency across all of the available

sources ….

But can the LED deliver on

Energy efficiency ?

Long life expectancy ?

Colour quality ?

Cost effectiveness ?

Light delivery ?

The benchmark for energy efficiency is provided by Building Regulations: Part L.

Energy efficiency

Energy efficiency

LED technology comes at a price.

There is a commercial balance that has to be achieved

re. cost v. life to justify energy savings.

Long life expectancy

Long life expectancy

Long life expectancy

LED light quality is varied – much of it poor.

The commercial market for LEDs is enormous and the most profitable fixtures are the ones that can

be bought cheap and sold dear.

Poor colour is a major factor in that cheapness.

Colour quality

Colour quality

SunlightSpectral Power Distribution(~100 numbers)

CIE 1931Chromaticity (xy or HSB)(2-3 numbers)

Black Body CurveColor Temperature(1 number)

Colour quality

David MacAdam – a scientist at Kodak – performed the first basic research in the late 1940’sFound a JND (Just Noticeable Difference) in color varied statistically by observer, size, and orientation in CIE 1931

Colour quality

• CIE 1931 diagram, focused on the 3000K point.

• Data points represent color points of approximately 1000 XSM 3080-01 modules, manufactured in January 2009. All units produced are shown.

• All modules are within 3 MacAdam Ellipses

• 99% of the modules are within 2 MacAdam Ellipses

Cost effectiveness is more than energy efficacy.

The cost of an LED fixture supports the overall performance of its Longevity and its Colour Quality.

Cost effectiveness

Cost effectiveness

Ø Halogen, 3khrs life and 16 replacements

Ø CFL / CMH, 12khrs life and 4 replacements

Ø LED, 50khrs life and 1 replacement

Cumulative maintenance required over 50khrs

How good a light beam does the LED produce?

This performance factor is often ignored.

typical tungsten halogen a good LED

Light delivery

Light delivery

•By using different phosphor mixes CRIs of 80+ or 95+ are available

•80 + modules have a 20% higher efficacy

•90+ modules have industry best colour-rendering properties, including vivid red portrayal (R9>90)

Light delivery

Light delivery

Ra R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15

Standard XSM 81 80 85 89 81 78 80 86 66 16 64 79 58 81 93 75

Artist Series XSM 98 98 99 98 98 98 97 98 98 96 99 98 88 98 98 98

Typical IR coated Halogen Dichroic 98 98 99 99 99 98 98 99 97 92 97 98 97 98 99 97

Typical Compact Metal Halide 82 90 94 69 82 81 81 87 71 27 59 62 55 93 78 88

Typical Compact Fluorescent 87 91 93 86 91 89 90 88 70 17 76 91 81 93 92 81

Light delivery

Ra R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15

Standard 81 80 85 89 81 78 80 86 66 16 64 79 58 81 93 75

Artist 98 98 99 98 98 98 97 98 98 98 99 98 88 98 98 98

The answer is certainly

YES the LED can deliver on all these issues …

Energy efficiency

Long life expectancy

Colour quality

Cost effectiveness

Light delivery

But not every LED …….. Sorry.

Thank you for your time