19 p benitez

SMS freeforms P. Benítez1,2, J.C.Miñano1,2, R. Mohedano2 1

UPM, Spain 2 LPI, USA

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Index • • • • • •

Introduction SMS 3D design process Example 1: Automotive headlamp Example 2: Color mixing collimator Example 3: Imaging Conclusions Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Design problems in Nonimaging Optics •

Bundle coupling: Source and target ray bundles are given.

Maximum coupling efficiency is required. o o o o o

•

Collimators Condenser optics for a projector Light injection into an optical fiber Radiation sensors Photovoltaic concentrator

E(source) ≈ E(target)

Prescribed illuminance: The source ray bundle and the output illuminance distribution on the target are given. o o o o

Automotive headlights Street lights E(source) << E(target) RGB color mixing E = etendue = “size” of the ray bundle (in phase space) Backlights Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Why freeforms in Nonimaging Optics?

• When source, target or volumetric constrains are nonsymmetric, symmetric solutions don’t work • Freeforms give you more degrees of freedom • Freeforms allow for fewer surfaces and parts because they can perform multiple functions

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Design problems in Nonimaging Optics Prescribed illuminance

D. Michaelis et al., SPIE Vol. 7059, (2008) Pablo BenĂ­tez et al.

E(source) << E(target)

Spanish Optical Designersâ&#x20AC;&#x2122; Meeting, Oct 3, 2013

Design problems in Nonimaging Optics Bundle coupling

P. Benitez et al., “Squeezing the etendue”, in Illumination Engineering, (Wiley 2013) Pablo Benítez et al.

E(source) ≈ E(target)

Spanish Optical Designers’ Meeting, Oct 3, 2013

Design problems in Nonimaging Optics Prescribed illuminance

E(source) << E(target) Pablo Benítez et al.

Bundle coupling

E(source) ≈ E(target)

Spanish Optical Designers’ Meeting, Oct 3, 2013

Design methods in Nonimaging Optics 1. String method (1960’s) 2. Flow line method (1970’s) 3. Taylored Edge-ray method (1980’s) 4. Poisson bracket method (1980’s) 5. Lorentz geometry method (1990’s)

2D 2D and 3D

6. Point-source Differential Equation methods (1960’s) 7. Numerical optimization methods (1990’s) 8. Simultaneous Multiple Surface (SMS) method (1990’s) 2D = rotational or linear symmetry 3D = freeform Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 8

Index • • • • • •

Introduction SMS 3D design process Example 1: Automotive headlamp Example 2: Color mixing collimator Example 3: Imaging Conclusions Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

The SMS 3D • The method solves a partial functional differential equation • One full curve in one of the surfaces can be chosen (to partially control a third wavefront pair)

WFi1

optical path length L1

WFi2

optical path length L2

2 free-form optical surfaces

WFo2

WFo1

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 10

Input data

Input wavefronts

Output wavefronts

• Input wavefronts • Ouput wavefronts • Choose L1 & L2 • Type of surfaces (e.g., XX)

X = metallic reflection

R = refraction

I = total internal reflection

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 11

SMS - Chain

Input wavefronts

Output wavefronts

• Select P0 and N0

We choose P0 on the primary mirror Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 12

SMS - Chain

Input wavefronts

Output wavefronts

• Select P0 and N0 • Calculate P1 that matches L1

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 13

SMS - Chain

Input wavefronts

Output wavefronts

• Select P0 and N0 • Calculate P1 that matches L1 • Calculate P2 that matches L2 • Repeat the process for P3, P4, etc.

• Go back to the initial point P0, then calculate the points P-1, P-2, etc.

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 14

SMS - Ribs

Seed Rib

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 15

SMS - Skinning

Seed Patch

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 16

Index • • • • • •

Introduction SMS 3D design process Example 1: Automotive headlamp Example 2: Color mixing collimator Example 3: Imaging Conclusions Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Example 1: Low beam headlamp design It is a prescribed illuminance problem     

Specs defined by regulations (ECE, SAE) Typically 20 min/ max test points/ fields Gradient Specifications Homogeneity Car producer additional specifications

Horizontal Spread

Low glare values

Gradient/Cut-off

Elbow/ Shoulder Hotspot

Low foreground

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 18

Projected images of the source

Source

Pinholes

Images

HL Optical System

Screen at 25 m

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Projected images of the source

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Single freeform vs SMS freeforms H

H V V H H V V

Single freeform surface • Design controls the position of ONE point of the source image • It does NOT control its size, shape and rotation

SMS freeform surfaces • Design controls THREE points of the source image • Therefore, it DOES control its size, shape and rotation.

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 21

Freeform RXI automotive headlamp Seed rib

Spines Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 22

Freeform RXI automotive headlamp

Measured efficiencies: • 84% HB (Al mirror; AR coatings) • 75% LB (Al mirror; no AR coatings) US 7,460,985 & International patents pending Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 23

Freeform RXI automotive headlamp

Jewel Eye™ LED headlamps of the 2014 Acura RLX

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 24

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 25

Index • • • • • •

Introduction SMS 3D design process Example 1: Automotive headlamp Example 2: Color mixing collimator Example 3: Imaging Conclusions Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Unwanted effects

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013 27

Example 2: Color mixing collimator It is bundle coupling and prescribed illuminance problem

y

z

x

freeform collimator Pablo BenĂ­tez et al.

Spanish Optical Designersâ&#x20AC;&#x2122; Meeting, Oct 3, 2013

The metal-less Grooved-RXI 32 mm

1.3 mm

Two Total internal reflections at both groove sides

Pablo BenĂ­tez et al.

Spanish Optical Designersâ&#x20AC;&#x2122; Meeting, Oct 3, 2013

Statement of the problem WFB WFA

Groove edge line

r t

r vo r vi Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

D. Grabovičkić, et al.

Opt. Express 19, (2011)

Color Mixing V-groove back surface

LEDs

1.25 mm

h -h

R

G

G

B

0.1 mm

Analysed with

Metal-less RXI, true colour far field pattern

Conventional RXI, true colour far field pattern

Pablo BenĂ­tez et al.

Spanish Optical Designersâ&#x20AC;&#x2122; Meeting, Oct 3, 2013

Color Temperature & dimming LEDs

V-groove back surface

1.25 mm WW

CW

CW

NW

0.1 mm

Analysed with

Metal-less RXI, true colour far field pattern

Conventional RXI, true colour far field pattern

Pablo BenĂ­tez et al.

Spanish Optical Designersâ&#x20AC;&#x2122; Meeting, Oct 3, 2013

Prototypes

grooved RXI

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Measurements

LED

LED On

LED Off Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Measurements Simulated intensity distribution

Measured intensity distribution

• Measured maximum intensity 22 cd/lm (29 cd/lm simulated) • Measured efficiency (in ±20º)= 96% of simulated value Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Index • • • • • •

Introduction SMS 3D design process Example 1: Automotive headlamp Example 2: Color mixing collimator Example 3: Imaging Conclusions Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Application of SMS method in Imaging SMS 2D (rotational optics)

SMS 3D (free form optics)

Image plane

Up to 6 aspheres

Up to 2 free-forms

J. Infante, PhD dissertation, 2013

L. Wang, PhD dissertation, 2012

Pablo BenĂ­tez et al.

Spanish Optical Designersâ&#x20AC;&#x2122; Meeting, Oct 3, 2013

Advantage of freeforms

J.C. Miñano et al., OSA freeform incubator meeting, Washington D.C. (2011)

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Imaging with high aspect ratio SMS lens

SMS lens + optimization

F.Duerr et al., Opt.Express 20,10839–10846(2012)

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Imaging with high aspect ratio Optimised rotatonal lens RMS < 11 µm

SMS lens + optimization RMS < 6 µm

F.Duerr et al., Opt.Express 20,10839–10846(2012)

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Index • • • • • •

Introduction SMS 3D design process Example 1: Automotive headlamp Example 2: Color mixing collimator Example 3: Imaging Conclusions Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Conclusions • SMS 3D design method allows for designing two freeform surfaces using up to three wavefront pairs.

• SMS 3D controls size and orientation of source projected.

• SMS 3D can handle prescribed illuminance and boudle cupling problems with extended sources, including color mixing • SMS freeforms are also excellent starting points for optimizations Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

LEGAL NOTICE Devices shown in this presentation are protected by the following US Patents and US and International Patents pending: 6,639,733; 2001069300; CA2402687; 2003282552; 6,896,381; 20040246606; 20050086032; 200501295; PCT publication WO/2007/016363

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Thank you!

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Design problems in Nonimaging Optics Prescribed illuminance

D. Michaelis et al., SPIE Vol. 7059, (2008)

Bundle coupling

P. Benitez et al., “Squeezing the etendue”, in Illumination Engineering, (Wiley 2013)

Pablo Benítez et al.

Spanish Optical Designers’ Meeting, Oct 3, 2013

Design problems in Nonimaging Optics Prescribed illuminance

E(source) << E(target) Pablo Benítez et al.

Bundle coupling

E(source) ≈ E(target)

Spanish Optical Designers’ Meeting, Oct 3, 2013