Manufacturing of LED Optical Functional Structures and 3D … · 2017. 10. 21. · USA VEECO K465i...

2014 Optical Functional Structures for LEDs SCUT

Manufacturing of LED Optical Functional

Structures and 3D Packaging Technology for LEDs

Pro. Yong Tang


Outline

1.Background

2.Technical problems in optical

functional structures

3.Trends of optical structure

manufacturing

1.Light extraction structures

2.Light-controlling structures

3.Key equipments

4.Conclusions


How to accelerate the development of LEDs?

—Optical functional structure manufacturing

1. Background

Chip Level Package Level Product Level

Key problem

CREE DA1400,with light

functional structure

Luminas LEDs, with wafer

level phosphor coating

PHILIPHS lightings,

with freeform remote

phosphor lens

Optical functional structures


Optical functional structure categorization

•Light extraction structures——Improve light output and enhance luminous efficiency. •Light-controlling structures——Control the path of light and distribute the energy.

1. Background

ALight extraction

structures

ALight-controlling

structures


•Patterned Sapphire Substrate（图形化衬底）

•Surface Texturing（表面粗化）

•Chip Shaping（芯片形状优化）

•Packaged plate structure（封装基板结构）

•3D Package (集成式三维封装)

2. Technical problem in optical functional structures

2.1 Light extraction structures


Schematic and SEM of PPS

Patterned Sapphire Substrate（图形化衬底）

Compared with the flat substrate, PSS can improve the

luminous efficiency of LED chips by over 40%. It has been a

popular method in high power LED chips.


Surface texturing（表面粗化）

Periodically textured LED chips

Surface texturing to enhance the light extraction

Digital Modeling

Digital modeling of the texture is a

possible way to investigate the

relationship between the structures

and optical performance.


Chip Shaping （形状化芯片结构）

Chip shaping to enhance light extraction

The method is simple and

feasible in the LED industry.

Principle of chip shaping to enhance light extraction


Chip Shaping （形状化芯片结构）

Chip shaping can reduce energy loss due to totally internal reflection, and improve

luminous efficiency. SCUT has applied diamond cutting methods to chip shaping and

improved the luminous efficiency by >20%.

V-cut structures on surface of CREE DA 1000 Light output of CREE DA 1000

LED chips

V-cut array structures on DA chip

Light output of DA chip with V-cut Array structures

Simulations of the angular distribution of CREE DA 1000

LED chips

Simulations of the angular distribution of V-cur Array DA chips


Packaged Plate Structure

30 453 2

452

o oc cp

o cc p

n < 1.41

n ≥ 1.41 22.5°~45°

Expression of the optimized patterned

structures

n = 1.41

Traditional integrated planar light source PLS integrated planar light source

Case 1 Case 2

LED chips LED chips

Left limit light

Right limit light

Left limit light

Right limit light

Escape cone


Calculations

Simulations

Experiments

Consistent

The light output power has been

enhanced by 41.07%, when the inclination angle is

45°.

Improve the light output

efficiency by：

1）changing the second

incidence angle

2）reducing heat buildup

Packaged Plate Structure


3D Package (集成式三维封装)

1）Low chip density 2）Light-absorption between chips 3）Half-peak-side angle <1800

Flat packaged structure

3D packaged structure

(a) (b)

Light 1 Light 2

Chip height h = 150 μm

Sub-plane number N P

lan

e ef

fect

ive

gro

wth

fa

cto

r η

3'

Optimized plane number N=3



Compared with flat packaged structure

Luminous Flux: 45% ↑ Lumen density: 18 Times

Full space intensity angular distribution

Half-peak-side angle=2X120°

LED chips leadframe

silicone

x direction

y direction

Power (W)

Lu

min

ou

s F

lux

(lm

)

3D package

3D package

Flat package

Flat package

Lu

min

ou

s ef

fici

ency

(lm

/W)


(a) (b) Traditional halogen lamp

automobile headlights 3D packaged LEDs

automobile headlights


3D package can effectively substitute traditional halogen lamp and apply to the automobile headlights. The brightness under 15W can compete 60W halogen lamp.


•Freeform Lenses （自由曲面光控结构）

•Micro Lens Array（微透镜阵列）

2.2 light-controlling structures



Freeform Lenses （自由曲面光控结构）

The use of the freeform lenses light controlling stuctures can make the illuminance

distribution more uniform in the space. The traditional design method is inefficient and

experiential dependent. The new energy-negative feedback method is suitable for the high

power LEDs.

With the increasing of the light source dimension, the light spot has a trend to be out of control

Manually adjust by experience

Reduce the experiential dependence

EFFL arithmetic for lens design

Input the illuminance distribution error into the arithmetic

Spot radius (normalized units)

Illu

min

ati

on

(n

orm

ali

zed

un

its)



22

11

max

1

001

2 ( ) 2 ( )sin

2 ( )sin2 ( )

nx

i ix

i

nR

i i

i

k f x xdx I d

I dk f x xdx

Design of freeform lenses for multi-chip packaged LEDs

Modified freeform lens

Original freeform lens


Illu

min

atio

n (

nor

mal

ized

unit

s)

Energy concentration area

计算透镜自

由曲面

计算新的能

量守恒公式

输出点文件

开始

结束

建立扩展光源

照明模型

Monte Carlo

光线追迹计算非均匀

能量分布

函数

是否满足

设计要求否是

注：

虚线框采用点光源自由曲面透镜算

法。

Begin

End

Yes No

Calculate freeform lens

Monte Carlo Ray Trace

Satisfy design requirement or not

Output point file

Calculate the non-uniform

energy distribution function

Establish extended illumination model

Note: The process surrounded by a dashed box uses a point-source freeform lens algorithm

calculate the new energy conservation

equation


Illu

min

atio

n (

norm

aliz

ed u

nit

s)

)(2 xfE

)()( 2211 xfkxfkE



(b) 1st generation (a) Before optimation

(c) 5th generation (d) 10th generation

(e) 15th generation (f)18th generation

Spot radio R1(mm)

En

ergy /

are

a (n

orm

aliz

ed u

nit

s) Optimized times

LED Package

LED Package

LED Package

LED Package



Spot radius of 3D packaging lighting system R1(cm)

Illu

min

ance E

v（

norm

alized u

nit

s）

Height 2m

Height 1.75m

Height 1.5m


Micro Lens Array（微透镜阵列）

SEM image of nano-imprint micro lens array thin film

Micro lens array on the COB surface SEM image of micron micro lens array structure

Principle of micro lens array to enhance light extraction

Micro lens array can enhance the luminous efficiency and fine control the path of the emitted light. It can improve the light quality especially the CCT angular distributions.


2.3 Key equipments for optical structure manufacturing

•Metal Organic Chemical Vapor Deposition

（金属有机气相沉积装备）

•Photo-etching Equipments （光刻装备）

•Plasma Etching Equipments（等离子蚀刻装备）

•High Speed Cutting Equipments（高速精密切割装备）

•High Pressure Molding Equipments (高压力模塑装备)



MOCVD（金属有机气相沉积装备)

USA VEECO K465i MOCVD German AIXTRON G5 MOCVD

Application：Grow buffer layer on sapphire substrate, P-GaN、MQW、N-GaN etc. The most expensive equipment for LED industry. Status: monopolized by USA VEECO, German AIXTRON. In China, more than 20 companies devote to investigation and has made some prototypes.


Application： Transfer the graphics on the mask to the photoresist coated wafer

German SUSS MicroTec-MA100/150e Gen2 USA ABM-ABM/6/350/NUV/DCCD/M Korea MIDAS-MDA-400M

NO.45 Research Institute of CETC BA-401A

The Institute of Optics And Electronics Chinese Academy of

Science SURE-2000SA

Status：The exposure accuracy and the system stability from inland supplier is still not enough.

Photo etching Equipment（光刻装备）


Application：Plasma etching the wafer after exposure, forming circuits or special pattern on the wafer.

Status ： The sub-surface quality control is difficult and the process need a long time.

China Taiwan FULIN Technology

iDE200-Etcher

China North Microelectronics

ELEDE 330 ICP

Plasma Etching Equipment（等离子蚀刻装备）


Application：

•Manufacture light extraction enhancement structure on

the chip surface

Technical requirements：

•High-speed dicing （Speed>40000rpm）

•Diamond composite cutting tools

•Ultra-hard & brittle materials machining

Advantage：

•High efficiency，can process hard and brittle

materials

•Accurate processing section；

•High surface quality；

Status ：almost blank inland

Hard and brittle materials micromachining equipment

High Speed Cutting Equipment（高速精密切割装备）

Ultra-high-speed precision cutting equipment


Application： Molding freeform lenses or micro lens array. Status： The key parameter is the utilization of encapsulant material. The utilization of high pressure molding equipment abroad is almost 100%, and only 85%-90% inland.

Japan TOWA

PMC1040-S

Sumitomo Heavy Industries, Ltd.

SY-COMP

High Pressure Molding Equipment (高压力模塑装备)


Photonic crystal ：Enhance the light output power by the specific band-gap of photonic crystal.

Difficulties：Lack of low cost & large area nano fabrication methods.

Photonic crystal structure by triangle complex drilling

"Pyre" photonic crystal structure

Photonic crystal structure with honeycomb array

Photonic crystal structure with

a columnar array

3. Development trend of optical functional structures


Industrial production of optical functional structures by mechanical methods

3. Development trend of optical functional structures

Industrial production


4. Conclusions

Optical functional structures for LEDs

Trend of optical structure manufacturing

1.Light extraction structures

2.Light-controlling structures

3.Key equipments

Functional structures by mechanical methods


Thank You!

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Manufacturing of LED Optical Functional Structures and 3D … · 2017. 10. 21. · USA VEECO K465i...

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