Design Considerations with LED Package Primary Optics · 1. LED package design concepts –...
Transcript of Design Considerations with LED Package Primary Optics · 1. LED package design concepts –...
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Ralph C. Tuttle 2017 DOE SSL R&D Workshop 2 February 2017
Design Considerations with LED Package Primary Optics
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1. LED package design concepts – optimizing light extraction from LEDs. 2. Primary Optics: benefits of a “Flat Lens” vs “Spherical Lens”
3. Applications of “Flat Lens” LEDs in designs.
OUTLINE:
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Light extraction of LEDs is governed by Snell’s Law.
Where n = refractive index of material
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Light Emission into air for InGan LED chips
2.5 sin ϴC = 1.0 sin 90 ϴC = .4 ϴC = 23.6‡
LED Chip n = 2.5 23.6‡
Air n = 1.0
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Silicone: n = 1.5
Silicone Encapsulants (n = 1.4 to >1.5) are used as an index matching medium.
2.5 sin ϴC = 1.5 sin 90 ϴC = .6 ϴC = 36.9‡
LED Chip n = 2.5 36.9‡
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LED Chips are processed to maximize light extraction.
Roughened Surface
Shaped Chip
Micro Lens Patterning
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LED Chip n = 2.5
Silicone: n = 1.4 to 1.55
Silicone is molded in a spherical dome above LED chip. (Increases light output by >10%)
Air n = 1.0
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Spherical Lens vs Flat Lens Packages
XP-L “High Density” LED XP-L “High Intensity” LED
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High Density (Domed) High Intensity (Flat) Footprint 3.5mm X 3.5mm 3.5mm X 3.5mm Package Height 2.7mm 1.0mm Max Current 3A 3A LF @ 1A 450 lumens 405 lumens Efficacy @ 500lm 145 lpw 132 lpw Intensity: Cd @ 1A 100% 188%
LED Package Comparison
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Beam Angle 135° Beam Angle 115°
Far Field Patterns
High Density (Domed) High Intensity (Flat)
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Color over Angle
ΔC
CT
(K)
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XP-L XPL-HI
Optical Source Size
(1.0X) (1.5X)
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3.2 cd/cm2/lumen 7.8 cd/cm2/lumen
Average Surface Luminance per Lumen
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Measured using Carclo 10755R1 TIR optic
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cand
ela
watts
Cd/W for Spherical Lens vs Flat Lens XPL LED
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• 83% smaller and lighter than a PAR38 • Only 8W of system power • 9000 cd
Nano-Punch Track Light Concept – XP-L High Intensity
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XQ-E 1.6mm X 1.6mm
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Domed Lens 173 lumens 281 lx @ 2m
Flat Lens 159 lumens 643 lx @ 2m
Small Diameter (15mm) AAA Flashlight Retrofit (XQ-E)
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Lighting Applications
Non-Directional
Directional
Downlight
Linear
Outdoor/High Bay
Portable
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1. LED package design concepts – optimizing light extraction from LEDs. 2. Primary Optics: benefits of a “Flat Lens” vs “Spherical Lens”
3. Applications of “Flat Lens” LEDs in designs.
OUTLINE:
Is Candela/Watt an appropriate metric of a products efficacy for certain applications?
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