The Life and Times of the LED . . .

and why it ain’t that Simple

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

Until … this came along

In 1907, Henry Joseph Round discovered the principle of the semi-

conductor – but no one knew what to do with it.

In 1927, Oleg V. Losev, in the USSR published a

paper on light emission using Silicon Carbide

(carborundum).

No one outside of the USSR read it for thirty

years.

LED technology kicked-off in 1961 when Bob

Baird and Gary Pittman, working for Texas

Instruments developed the infra-red LED – by

‘accident’.

Their LED was built using s substrate of Gallium

Arsenide GaAs – a compound still is

commercial use in LED technology.

It is classed as a carcinogen in California

Gallium Nitride. (GaN)

. . . while the dust from GaN is an irritant to

skin, eyes and lungs, it is non-toxic and bio-

compatible in its bulk form.

. . . and the preferred source of Gallium is

Trimethylgallium, which has the tendency is catch fire on contact with air.

Its also a by-product of bauxite mining.

This is bauxite mining . . .

. . . in Guyana

though this is the Guyana

that we get told about

and bauxite makes aluminium . . .

. . . oh, oh

Anyway: eventually we got this …

Which became these … amongst many others

And which has introduced us to a whole new world of l ighting opportunit ies …

Bulbs:

Ref

lect

or

(light)(heat)

LEDs: 90°-140° viewing angle

(light)

(heat)

(light)

The fundamental dif ferences:– Directionality of generated

l ight• Omni-directional vs.

directional

– Means of evacuating generated heat

• Convection vs. conduction

Here’s the thing …

LED technology introduced us to a whole new way of looking at our old famil iar fr iends …

But the LED has also changed the shape of l ighting

This is a conventional (energy-saving) CFL downlight

And this is a comparable LED downlight

Lightweight structure with minimal metalwork

Almost 50% of the weight of the downlight is in the aluminium heatsink mounted on the back

whereas the working part is very small indeed

whereas the working part is very small indeed

But what happens when we want to get rid of i t?

But how do we get r id of it?

Electronic waste is the fastest-growing part of the world’s garbage stream. Improperly disposed of, the lead, mercury and other toxic materials inside e-waste can leak from landfills.

75% of the aluminium produced since the 19th century is still in use. The demand for aluminium is set to increase from 40M tonnes to 70M tonnes by 2020, over two-thirds of that demand will have to come from primary sources,

But how do we get r id of it?

For every ton of aluminum produced, the process generates approximately 24 kg of waste. In most cases it’s only partially reused and the rest of cases it’s discharged, contributing to the problem of saturation in landfills

A lot of exported e-waste ends up in Guiyu, China, where peasants heat circuit boards over coal fires to recover lead, while others use acid to burn off bits of gold. Guiyu has the highest level of cancer-causing dioxins in the world and elevated rates of miscarriages.

SO … what do we want from the LED?

Much of what the l ighting designer wants is

consistency across all of the available sources

….

But can the LED deliver on

Energy eff iciency ?

Colour quality ?

Light performance ?

Much of what the l ighting designer wants is

consistency across all of the available sources

….

And what about ….

Cost effectiveness ?

Long l ife expectancy ?

Much of what the l ighting designer wants is

consistency across all of the available sources

….

But can the LED deliver on

Energy eff iciency ?

Colour quality ?

Light delivery ?

Cost effectiveness ?

Long l ife expectancy ?

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

Energy eff iciency

Energy eff iciency

LED light quality is varied – much of it poor.

The commercial market for LEDs is enormous and the most profitable f ixtures 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 f irst basic research in the late 1940’sFound a JND (Just Noticeable Difference) in color varied stat ist ically 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

How good a l ight beam does the LED produce?

This performance factor is often ignored.

typical tungsten halogen a good LED

Light performance

Light performance

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

•80 + modules have a 20% higher eff icacy

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

Light performance

Light performance

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

Cost effectiveness is more than energy eff icacy.

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

Cost effectiveness

Cost effectiveness

Ø Halogen, 3khrs life and 16 replacementsØ CFL / CMH, 12khrs life and 4

replacementsØ LED, 50khrs life and 1 replacement

Cumulative maintenance required over 50khrs

LED technology comes at a price.

There is a commercial balance that has to be achieved re. cost v. l i fe to justify energy savings.

Long l ife expectancy

Long life expectancy

Long life expectancy

The answer is certainly

YES the LED can deliver on all these issues …

Energy eff iciency

Colour quality

Light delivery

Cost effectiveness

Long l ife expectancy

But not every LED …….. Sorry.

Thank you for your t ime