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Protective Materials Over LEDs –and Associated Optical Effects

Presented by Jake Steinbrecher • Dow Performance SiliconesStrategies In Light, February 13, 2018

Why Can’t We Just Have “White” Light?

2

Paul AndreauPhoto: ® 2008 Artists Rights Society (ARS), New York / ADAGP, Paris

Benefits of Protective Materials - Conformal Coatings

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4000K test part with DOWSIL™ 1-2577 Low VOC Conformal Coating

Silicone, Acrylic, Urethane

• Protect against environmental ingress, corrosion, etc.

• Thin layer provides little impact on light quality

Protective Materials – Conformal Coatings

4

4000K Test Part, No Material4000K Test Part with DOWSIL™ 1-2577

Low VOC Conformal Coating

Benefits of Protective Materials - Encapsulants

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4000K test part with DOWSIL™ EI-1184 Encapsulant

• Protect against environmental ingress, corrosion, etc.

• Impact protection

Silicone, Acrylic, Urethane

Protective Materials - Encapsulants

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4000K Test Part, No Material4000K Test Part with DOWSIL™

EI-1184 Optical Encapsulant

Benefits of Protective Materials - Molded Lens

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4000K test part with DOWSIL™ MS-1002 Moldable Silicone

Silicone, PC, PMMA

• Protect against environmental ingress (when sealed)

• Impact protection• Little impact on light quality

Protective Materials - Molded Lens

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4000K Test Part, No Material4000K Test Part with DOWSIL™

MS-1002 Moldable Silicone

Lens design courtesy of:

Disadvantages of Protective Materials

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Effects on Light Quality• Color shift• Lumen depreciation

Cost

Test parts, using DOWSIL™ 1-2577 Low VOC Conformal Coating, DOWSIL™ EI-1184 Encapsulant , and DOWSIL™ MS-1002 Moldable Silicone

4000K3000K

5000K HOK International, Photo: Farid Khayrulin

Protective Materials – Effects on Light QualityTypical LED Package

Blue rays from the LED chip will:1) Go to air through silicone encapsulant material (RI 1.53)2) Hit phosphor particles and emit rays with other spectrum (e.g. yellow, red)

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Phosphor Silicone Encapsulant(RI 1.53)

Reflector CupLED Chip

1

2

Air (RI 1.00)

Protective Materials – Effects on Light QualityTypical LED Package

Blue rays from the LED chip may:3. Reflect at the interface of silicone encapsulant and air, due to Total Internal

Reflection (TIR). In this example, the critical angle θ1 is equal to sin-1 (1/1.53), which is 40.8 degrees. Any rays that hit this interface with an angle bigger than 40.8 degrees will be reflected, and may interact further with phosphor particles.

11

Phosphor Silicone Encapsulant(RI 1.53)

Reflector CupLED Chip

1

23

Air (RI 1.00)

Protective Materials – Effects on Light QualityTypical LED Package + Protective Material(s)

Blue rays from the LED chip may:4. Have a better chance of escaping at the interface of silicone encapsulant and

protective material due to TIR. In this example, the critical angle θ1 is equal to sin-1

(1.41/1.53), which is 67 degrees. This leads to more blue light rays escaping and less interaction with phosphor, leading to increased color temperature.

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PhosphorSilicone Encapsulant(RI 1.53)

Reflector CupLED Chip

1

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Air (RI 1.00) Silicone Protective Material (RI ~1.41)

Protective Materials –DOWSIL™ 1-2577 Low VOC Conformal Coating

133000K, 4000K , and 5000K test parts with

DOWSIL™ 1-2577 Low VOC Conformal Coating

2000

2500

3000

3500

4000

4500

5000

5500

3000K 4000K 5000K

Cor

rela

ted

Col

or T

empe

ratu

re (º

K)

LED Linear Type

DOWSIL™ 1-2577 Low VOC Conformal Coating, Effects on Correlated Color Temperature

BareCoated

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

3000K 4000K 5000K

Lum

inou

s Fl

ux (l

umen

s)

LED Linear Type

DOWSIL™ 1-2577 Low VOC Conformal Coating, Effects on Luminous Flux

BareCoated

Protective Materials –DOWSIL™ EI-1184 Optical Encapsulant

143000K, 4000K, and 5000K test parts with DOWSIL™ EI-1184 Optical Encapsulant

0.0020.0040.0060.0080.00

100.00120.00140.00

3000K 4000K 5000K

Lum

inou

s Fl

ux (l

umen

s)

LED Linear Type

DOWSIL™ EI-1184 EncapsulantEffects on Luminous Flux

Bare

Encapsulant

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

3000K 4000K 5000K

Lum

inou

s Fl

ux (l

umen

s)

LED Linear Type

DOWSIL™ EI-1184 EncapsulantEffects on Luminous Flux

Bare

Encapsulant

2000

3000

4000

5000

6000

7000

8000

9000

3000K 4000K 5000KCor

rela

ted

Col

or T

empe

ratu

re (º

K)

LED Linear Type

DOWSIL™ EI-1184 EncapsulantEffects on Correlated Color Temperature

Bare

Encapsulant

Protective Materials –DOWSIL™ MS-1002 Moldable Silicone

153000K, 4000K, and 5000K test parts with DOWSIL™ MS-1002 Moldable Silicone

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

3000K 4000K 5000K

Lum

inou

s Fl

ux (l

umen

s)

LED Linear Type

DOWSIL™ MS-1002 Moldable SiliconeEffects on Luminous Flux

Bare

Lens

2000250030003500400045005000550060006500

3000K 4000K 5000KCor

rela

ted

Col

or T

empe

ratu

re (º

K)

LED Linear Type

DOWSIL™ MS-1002 Moldable SiliconeEffects on Correlated Color Temperature

Bare

Lens

DOWSIL™ Protective Materials – Effects at 3000K

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0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

Bare DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

Lum

inou

s Fl

ux (l

umen

s)

Luminous Flux

DOWSIL™ Protective Materials – Effects at 3000K

17

0.00

500.00

1000.00

1500.00

2000.00

2500.00

3000.00

3500.00

4000.00

4500.00

Bare DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

Cor

rela

ted

Col

or T

empe

ratu

re (º

K)

Correlated Color Temperature

DOWSIL™ Protective Materials – Effects at 3000K

18

0.00E+00

5.00E-04

1.00E-03

1.50E-03

2.00E-03

2.50E-03

3.00E-03

350 450 550 650 750 850

Spec

tral

Flux

Wavelength (nm)

Spectral Flux

Bare

DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

DOWSIL™ Protective Materials – Effects at 4000K

19

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

Bare DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

Lum

inou

s Fl

ux (l

umen

s)

Luminous Flux

DOWSIL™ Protective Materials – Effects at 4000K

20

0.00

1000.00

2000.00

3000.00

4000.00

5000.00

6000.00

Bare DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

Cor

rela

ted

Col

or T

empe

ratu

re (º

K)

Correlated Color Temperature

DOWSIL™ Protective Materials – Effects at 4000K

21

0.00E+00

5.00E-04

1.00E-03

1.50E-03

2.00E-03

2.50E-03

3.00E-03

350 450 550 650 750 850

Spec

tral

Flux

Wavelength (nm)

Spectral Flux

Bare

DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

DOWSIL™ Protective Materials – Effects at 5000K

22

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

Bare DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

Lum

inou

s Fl

ux (l

umen

s)

Luminous Flux

DOWSIL™ Protective Materials – Effects at 5000K

23

0.00

1000.00

2000.00

3000.00

4000.00

5000.00

6000.00

7000.00

8000.00

9000.00

Bare DOWSIL™ 1-2577 Low VOC Conformal Coating

DOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

Cor

rela

ted

Col

or T

empe

ratu

re (º

K)

Correlated Color Temperature

DOWSIL™ Protective Materials – Effects at 5000K

24

0.00E+00

5.00E-04

1.00E-03

1.50E-03

2.00E-03

2.50E-03

3.00E-03

3.50E-03

4.00E-03

4.50E-03

350 450 550 650 750 850

Spec

tral

Flux

Wavelength (nm)

Spectral Flux

Bare

DOWSIL™ 1-2577 Low VOC Conformal CoatingDOWSIL™ EI-1184 Encapsulant

DOWSIL™ MS-1002 Moldable Silicone

DOWSIL™ Protective Materials

DOWSIL™ 1-2577 Low VOC Conformal Coating• Minimally effects Luminous Flux and CCT

― But, provides the least amount of protection above bare components

DOWSIL™ EI-1184 Optical Encapsulant• Provides significant protection above

bare components ― But, reduces Luminous Flux and increases CCT

DOWSIL™ MS-1002 Moldable Silicone• Slightly increases Luminous Flux and CCT

― And, provides significant protection above bare components

25Ingarden & Ewy Architekci; Arata Isozaki & Associates Photo: Wojciech Wandzel

ThankYou

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Form No. 11-3883-01 26686