sms design method in 3d geometry: examples and applications

1

SMS design methodin 3D geometry:

examples and applicationsPablo Benítez, J.C. Miñano,

J. Blen, R. Mohedano, J. Chaves, O. Dross,M. Hernández, J.L. Álvarez, W. Falicoff

Light Prescriptions Innovators LLC

2

INDEX

Introduction

Statement of the problem

Design procedure

Examples

Application example: illumination

Conclusions

3

Free-form optics introduce degrees of freedom to solve nonimaging and imaging design problems with no symmetric solutions

Present manufacturing technology allows for free-form surfaces with high precision

Few nonimaging design tools are available:

• Most of them for punctual sources• All of them for only 1 free-form surface

INTRODUCTION

4

The SMS3D method designs simultaneously 2 free-form surfaces, which allows the control of extended sources

First example (SPIE’99): sharp-edge imaging lens that showed the perfect imaging of two object points in 3D

INTRODUCTION

5

B’


INTRODUCTION

First example (SPIE’99): sharp-edge imaging lens that showed the perfect imaging of two points in 3D

A’

y

zx

edge

B

A

6


First example (SPIE’99): sharp-edge imaging lens that showed the perfect imaging of two object points in 3D

INTRODUCTION

Last developments (here, SPIE’03): Generalization of the SMS3D*, with application to non-imaging design problems

*patent pending

7

STATEMENT OF THE PROBLEM

1 free-form optical surface

(Cartesian Oval)optical path length L

WFi

WFo2WFo

n=1

n=1.5

8

STATEMENT OF THE PROBLEM

2 free-form optical surfaces

optical path length L1

optical path lengths L2

WFi1

WFo2WFo1

WFi2

9

DESIGN PROCEDURE

N0SMS chain

n=1

n=1

n>1

• Choose L1 & L2

• Select P0 and N0

• Calculate P1 that matches L2

WFi2

WFo2

P0

P1

10

DESIGN PROCEDURE

P0

N0

N1

P2

N2

P-2

P-4

P-1 P-3

P4P6

P8

P3P5P7

P9

spines

SMS chain

P1

11

DESIGN PROCEDURE

R0 R-2R-4

R-3R-1

R1R3

R5

R2R4R6

R8

R7

R9

τN0

M

Seed rib R0

SMS ribs

Ribs & Spines = Surface skeleton

12

DESIGN PROCEDURE

R0

R1

R2R-2

R-4

R-1R-3

R4R6

R8

R3R5R7

R9

SMS ribs

Ribs & Spines = Surface skeleton

13

R1R3

R2

Σ0

Σ1

Σ2

Σ-2

Σ7 Σ-1

Σ-3

Σ4 Σ6 Σ8

Σ3 Σ5

Si

So

R0

R1

R2 R-2

R-4

R-1 R-3

R4 R6

R8

R3 R5

R7

R9

DESIGN PROCEDURE

SMS skinningSMS ribs

SMS spines

14

DESIGN PROCEDURE

2. SMS spine with WF1 & WF3

WFi1WFi2

2 free-form optical surfaces

WFo2WFo1

WFi3

WFo3

Seed rib R0

Seed rib selection criterion: 1. Geometrically constrained by application

Full coupling of WF1

and WF2

Coupling of WF3

along the seed rib

15

WFo1WFo2

WFo3

5 deg5 deg

EXAMPLES

Two mirror design (XX)

WFi2 WFi1

WFi3

1 mm

1 mm

SMS seed rib

16

EXAMPLES

Two mirror design (XX)WFo1WFo2

WFo3

5 deg5 deg

WFo1

WFo3

WFo2

10 deg5 deg

WFo3

5 deg

10 deg

WFo1WFo2

17

EXAMPLES


30°

WFo1WFo2

WFo3

5 deg5 deg

WFo1

WFo2

WFo3

5 deg

5 deg

18

EXAMPLES

Two mirror design (XX)WFo1WFo2

WFo3

5 deg5 deg

WFo1WFo2

WFo3

5 deg 5 deg

19

EXAMPLES


5 deg5 deg

5 deg 5 deg

20

RXI 3D

EXAMPLES

The RXI design

RXI 2D*mirror

mirror

α

*US patent application 09/810,959 in allowance

21

EXAMPLES

The RXI design

Lambertian emitterAperture aspect ratio W:H= 3:2Flashed area/Rectangle area = 93%Collection efficiency = 98%

H

W

D

Compactness D/W ≅ 1/3

22

V

H

APPLICATION: ILLUMINATION

Advantages versus 1 free-form reflector designs in automotive front lighting

Source Pinholes Images

HL Optical System

Screen at 25 m

23

V

H

V

H


1 free-form reflector

Filament source image

Advantages versus 1 free-form reflector designs in automotive headlamps

α αα

24

V

H

V

H


Critical for low luminance sources (as LED’s)

1 free-form reflectorFilament

source image

Lost flux!


2 SMS free-forms

V

H

25

Designs simultaneously 2 free-form surfaces, which allows the control of 2 wavefronts and partially a third one

Can lead to ultracompact devices with high efficiency, shape controlled shape, minimum area and maximum tolerances

Presently being applied to automotive headlights designs. Imaging applications being explored

Next objective: 3 free-form SMS surfaces

CONCLUSIONS

The SMS3D…

26

THE END

27

EXAMPLES

Wi2

Wi1

y

x

z

Seed rib R0 (arc of circumference)

Wo2Wo1


28

EXAMPLES

Seed rib R0(arc of circumference)

y

x

z

Ribs & Spines


29

90%

92%

94%

96%

98%

100%

50% 60% 70% 80% 90% 100%

Flashed area (%)C

olle

ctio

n ef

ficie

ncy

(%)

Rotational RXI

RXI3D

EXAMPLES

The RXI design

Aspect ratio = 3:2Flashed area/Rectangle area = 93%Collection efficiency = 98%

> 30%

>30% area reduction to produce a given intensity

This limit also applies for 1 free-form surface!

30


The higher control (sizes, rotation) of source image projection provides

Exit aperture shape controlled without efficiency lossHigher efficiencyIncreased tolerances to source displacements

Critical for low luminance sources (as LED’s)


31


Advantages vs 1 free-form surface illumination designs:

1. Smaller aperture area when the maximum intensity is prescribed.

2. Better control of the device contour

3. Further area reduction for patterns non-adapted to source shape

Far-field area to illuminate 2 SMS free-forms1 free-form refractive surface

LED imageprojected from 1 point of the exit aperture

Potential area reduction: up to aspect ratio

32


Potential advantages vs 1 free-form designs:

3. Higher control (sizes, rotation) of source image projection

Critical for low luminance sources (as LED’s) and limited area ⇒ big source projected imagesExit aperture shape controlled without efficiency lossHigher tolerances to source displacements for a given exit area

4. Simultaneous prescriptions of the far-field intensity and near-field illuminance can be achieved

33

• LPI has designed 3D SMS head lamps (incandescent and LED) that worked exceptionally well: Compact, efficient and with high intensity.

SMS in 3D: Free-Form Optics

Raytrace of SMS HL, incandescent, SAE Low Beam

sms design method in 3d geometry: examples and applications

Documents