Design Considerations with LED Package Primary Optics · 1. LED package design concepts – optimizing light extraction from LEDs. 2. Primary Optics: benefits of a “Flat Lens”

© 2016 Cree, Inc. All rights reserved © 2016 Cree, Inc. All rights reserved

Ralph C. Tuttle 2017 DOE SSL R&D Workshop 2 February 2017

Design Considerations with LED Package Primary Optics

© 2016 Cree, Inc. All rights reserved

2

Ralph C. Tuttle

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:


3

Ralph C. Tuttle

Light extraction of LEDs is governed by Snell’s Law.

Where n = refractive index of material


4

Ralph C. Tuttle

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


5

Ralph C. Tuttle

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‡


6

Ralph C. Tuttle

LED Chips are processed to maximize light extraction.

Roughened Surface

Shaped Chip

Micro Lens Patterning


7

Ralph C. Tuttle

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


8

Ralph C. Tuttle

Spherical Lens vs Flat Lens Packages

XP-L “High Density” LED XP-L “High Intensity” LED


9

Ralph C. Tuttle

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


10

Ralph C. Tuttle

Beam Angle 135° Beam Angle 115°

Far Field Patterns

High Density (Domed) High Intensity (Flat)


11

Ralph C. Tuttle

Color over Angle

ΔC

CT

(K)


12

Ralph C. Tuttle

XP-L XPL-HI

Optical Source Size

(1.0X) (1.5X)


13

Ralph C. Tuttle

3.2 cd/cm2/lumen 7.8 cd/cm2/lumen

Average Surface Luminance per Lumen


14

Ralph C. Tuttle

Measured using Carclo 10755R1 TIR optic


15

Ralph C. Tuttle

cand

ela

watts

Cd/W for Spherical Lens vs Flat Lens XPL LED


16

Ralph C. Tuttle

• 83% smaller and lighter than a PAR38 • Only 8W of system power • 9000 cd

Nano-Punch Track Light Concept – XP-L High Intensity


17

Ralph C. Tuttle

XQ-E 1.6mm X 1.6mm


18

Ralph C. Tuttle

Domed Lens 173 lumens 281 lx @ 2m

Flat Lens 159 lumens 643 lx @ 2m

Small Diameter (15mm) AAA Flashlight Retrofit (XQ-E)


19

Ralph C. Tuttle

Lighting Applications

Non-Directional

Directional

Downlight

Linear

Outdoor/High Bay

Portable


20

Ralph C. Tuttle

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?


CLICK TO ADD TEXT


Thank You!

[email protected]

Documents

Design Considerations with LED Package Primary Optics · 1. LED package design concepts – optimizing light extraction from LEDs. 2. Primary Optics: benefits of a “Flat Lens”