WP2: Gloss - xD Reflect2nde progress meeting of xDReflect MIKES — Espoo, Finland — 23th June 2014 WP2: Gloss Solid angle of illumination and detection (T3) Specular peak area (T4)

2nde progress meeting of xDReflect

MIKES — Espoo, Finland — 23th June 2014 1

Leader : Gaël Obein, LNE-CNAM ([email protected])

WP2: Gloss


MIKES — Espoo, Finland — 23th June 2014

WP2: Gloss

Solid angle of illumination and

detection (T3)

Specular peak area

(T4)

Full BRDF (T2)

Roughness (T5)

ISO/ASTM (T6)

Artefacts (T1)

T1: Manufacturing of the gloss artefacts T2: Measurements of the BRDF of the samples T3: Traceability of facilities for specular peaks measurements T4: Measurement of the specular peak area T5: Measurement of the roughness T6: Measurement of the specular gloss T7: Proposal for a gloss measurement



Selected Deliverables

D 2.1.1 Physical gloss scale of at least 40 artefacts CNAM Artefact févr-14

D 2.1.2

KUL D1.1

Document outlining the logistics and measurements to be made with

the gloss standards CNAM

PTB, INRIM,

CSIC, SP,

CMI, KUL

Document févr-14

2.2.1

KUL D2.1

Luminous BRDF of the artefacts measured: 5 incident angles, at

least 6 in-plane angles, at least 4 out-of-plane geometries CNAM KUL

Dataset,

Report août-14

D 2.2.2

KUL D2.2


least 6 in-plane angles, at least 4 out-of-plane geometries KUL Dataset août-14

D 2.2.4

KUL D2.3 Publication on the BRDF measurements on the gloss scale CNAM KUL Conf paper oct-14

D 2.3.1

KUL D3.1

Luminous BRDF for 3 directions of illuminations measured with small

solid angles, on 2 glossy samples KUL

CNAM PTB

INRIM CSIC

CMI SP

Dataset mar-15

D 2.4.1 Luminous BRDF for 3 directions of illumination , restricted around the

specular direction, on the black gloss artefact CNAM Dataset mai-14

D 2.4.2 Report on the evolution of the shape of the specular peak according

to the roughness and the geometry of illumination CNAM Report juil-14

D 2.5.1

Roughness of the selected 6 artefacts using a metrology atomic force

microscope, a roughness profilometer, a coherent white-light

interferometer and a confocal microtopograph

SP Dataset mai-14

D 2.5.2. Roughness measurements of the 6 selected artefact using an optical

roughmeter based on angle-resolved scattering theory CNAM Dataset mar-14

D 2.5.3 Publication on the different type of roughness for the sample of the

gloss scale, using a multiscale approach SP CNAM Publication juil-14



Selected Deliverables

D 2.1.1 Physical gloss scale of at least 40 artefacts CNAM Artefact févr-14

D 2.1.2

KUL D1.1

Document outlining the logistics and measurements to be made with

the gloss standards CNAM

PTB, INRIM,

CSIC, SP,

CMI, KUL

Document févr-14

2.2.1

KUL D2.1


least 6 in-plane angles, at least 4 out-of-plane geometries CNAM KUL

Dataset,

Report août-14

D 2.2.2

KUL D2.2


least 6 in-plane angles, at least 4 out-of-plane geometries KUL Dataset août-14

D 2.2.4

KUL D2.3 Publication on the BRDF measurements on the gloss scale CNAM KUL Conf paper oct-14

D 2.3.1

KUL D3.1

Luminous BRDF for 3 directions of illuminations measured with small

solid angles, on 2 glossy samples KUL

CNAM PTB

INRIM CSIC

CMI SP

Dataset mar-15

D 2.4.1 Luminous BRDF for 3 directions of illumination , restricted around the

specular direction, on the black gloss artefact CNAM Dataset mai-14

D 2.4.2 Report on the evolution of the shape of the specular peak according

to the roughness and the geometry of illumination CNAM Report juil-14

D 2.5.1

Roughness of the selected 6 artefacts using a metrology atomic force

microscope, a roughness profilometer, a coherent white-light

interferometer and a confocal microtopograph

SP Dataset mai-14

D 2.5.2. Roughness measurements of the 6 selected artefact using an optical

roughmeter based on angle-resolved scattering theory CNAM Dataset mar-14

D 2.5.3 Publication on the different type of roughness for the sample of the

gloss scale, using a multiscale approach SP CNAM Publication juil-14

Task 2.2 : Measurements of the BRDF of the

samples

Task 2.3 : Improvement of the traceability of

reference facilities for specular peak

measurements on gloss artefacts

Jan Audenaert

Light&Lighting Laboratory

www.lichttechnologie.be



6

• Purpose: determination of the luminous BRDF (ill. A) outside of the specular

reflection direction

• 8 samples received from CNAM (8/8 measured):

o B R1 n1 G3

o B R1 n2 G1

o B R2 n2 G1

o G R1 n2 G2

o G R1 n2 G3

o W R1 n2 G1

o W R1 n2 G3

o B R1 n1 G2

B = Black, W = White, G = Grey

n1 = 1.53, n2 = 1.47

R = Roughness scale G = gloss scale

Task 2.2 : Measurements of the BRDF of the samples

6



• Sample preparation (ASTM E2387):

o Set fiducial mark for X-axis (aligned with XB)

o Mark incident position

• Sample alignment using incident beam:

o If possible use Fresnel reflection (G2, G3, G4)

o Else align with mirror on back of sample (G1)

Noticed that sample case and sample surface are not 100%

parallel


samples

7



• Predefined measurement geometries:

o 5 incident angles

o For each incident angle, 9 scatter directions

45 measurements per sample


samples

8

θi (°) ϕi (°) θs(°) ϕs(°)

0 - 5 0

20 180 20 0

45 180 45 0

60 180 60 0

75 180 75 0

45 45

45 135

45 225

45 315



• Measurement setup:

o Xe light source

o High dynamic range ~6 decades

o Incident beam diameter ~ 1.3 cm

o Detector aperture diameter = 2.54 cm

o Dark signal corrected

o Correction for long term drift of Xe light source output

o Detector connected to ccd:

spectral measurements

Allows to calculate luminous BSDF as illuminated by illuminant A (requirements

from CNAM)

o Parameters used during measurement:

• Averaged over 3 measurements

• Maximum integration time of 30 seconds


samples

9




samples

10

0,010

0,100

1,000

10,000

100,000

1000,000

0,000 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000

BSD

F[1

/sr]

scatter angle [°]

G R1 n2 G2 Angle of incidence [°] 0.000

Angle of incidence [°] 20.000




0,010

0,100

1,000

10,000

100,000

1000,000

0,000 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000

BSD

F [1

/sr]

scatter angle [°]

G R1 n2 G3

Angle of incidence [°] 0.000Angle of incidence [°] 20.000Angle of incidence [°] 45.000Angle of incidence [°] 60.000Angle of incidence [°] 75.000




samples

11

• Remarks:

o Some bulk scattering present within the samples

Will affect measurement comparison (differences in

FOV of detector, incident light beam size, …)

• Large differences with CNAM measurements are

expected for the glossy samples (G2->G4) in the

specular reflection direction, due to aperture and detector

convolution



Task 2.3 : Improvement of the traceability of reference

facilities for specular peak measurements on gloss artefacts

12

• Finite incident light beam and detector aperture size

Limit instrument signature effect with deconvolution algorithm



Task 2.3 : Improvement of the traceability of reference

facilities for specular peaks measurements on gloss

artefacts

13

• 2 Samples chosen by CNAM:

o Incident angles and scatter directions to be determined



Laboratoire commun de métrologie LNE-CNAM

Task 2.4

Specular peak Characterization



CNAM gonioreflectometer: spatial line principle

(q, f) (X, Y)

Fourier optics

Mobile ring

Conoscopic

detection

Illumination

QTH lamp

Sample

holder

512 x 512 pixels

ccd matrix

1°



Determination of the present resolution of our Gonio

180°



Samples measurements

Effect of the incidence angle over the specular peak

qi Apparatus

function



Effect of the refractive index over the specular peak

Black n1 Black n2

Drefractive indices =0.06



How to measure mat samples?

By composing several pictures from the conoscope, according to an hexagonal system :

Beware !

- The morphology of the conoscope area in the Fourier plane is altered.

- We are not dealing with proper circles.

- The length parameter of the hexagonal system has to be adapted to propose a

sufficient level of redundancy

Excessive length parameters : Deformation (exaggerated)



Thank you for your attention



Task 2.5: Measurement of the roughness and of

the topography of the samples (SP, CNAM)

(Start Feb 14, End Jul 14)

Deliverables:

2.5.1 Roughness of the selected 6 artefacts using …(various methods) - SP

2.5.2 Roughness of the 6 selected artefact using an optical roughmeter

based on angle-resolved scattering theory - CNAM

2.5.3 Publication on the different type of roughness for the sample of the

gloss scale, using a multiscale approach - SP, CNAM

“Relationship of Roughness and Topography to Gloss using a multiscale

approach”



Instrumentation – overview

• Vertical Scanning White Light

Interferometer

• Roughness profilometer

• Atomic Force Microscope (AFM)

• Confocal microtopograph

• Angle resolved scatterometer

(CNAM)



l=635nm

23 June 2014 24

xDReflect meeting, Espoo

The scattered light intensity can be measured as a function of (x,y,q)

Incidence angle q0 : fixed (48°)

Detection angle q : varied by moving the detection arm in the incidence plane

Position(x ; y) : varied by means of a motion controller

Principle of the Angle Resolved Scatterometer



Angle Resolved Scatterometer

Scattered light mapping

Power Spectral Density

RMS Roughness

POWER SPECTRAL DENSITY (PSD) Square modulus of the Fourier Transform of the surface profile Roughness spectrum

Position (x,y) : fixed

Detection angle q : varied

The scattered light intensity is measured as a function of q Iscat=f(q)

The PSD is deduced and fitted to determine the rms roughness d

Laser @ 635 nm

Spot size 500 µm

Resolution 0.1 nm



Selected samples

• Different roughness type (R1, R2 and R3)

• Different gloss levels (G1, G3 and G4)

• Two different refractive indices (n1 and n2)

R2n2G3

R1n2G3



R1n1G1 CSI 50 160x120µm

CSI 50 40x40µm

AFM

AFM

(nm) CSI

(nm)

Sq 260 145

Sa 214 111

Pq 400 nm



R1n2G1

CSI 10 820x620µm CSI 50 160x120µm

CSI 50 40x40µm

AFM

(nm) CSI

(nm)

Sq 353 254

Sa 286 204

AFM 40x40µm



R1n2G3 CSI 50 160x120µm

CSI 50 40x40µm AFM

AFM

(nm) CSI

(nm)

Sq 66 68

Sa 54 51

Pq 150 nm



R2n2G3

CSI 50 160x120µm

CSI 50 40x40µm AFM

AFM

(nm) CSI

(nm)

Sq 35 96

Sa 29 83

Pq 250 nm



R3n1G4

AFM CSI 50 40x40µm

Pq 5 nm

Sq 15 nm

Sq 2 nm

CSI 50 160x120µm



R3n2G4

CSI 50 160x120µm

CSI 50 40x40µm

CSI 10 820x620µm

AFM

Sq 2 nm

Sq 7 nm



Comparison fine details - R3n1G4 and R3n2G4

R3n1G4

R3n2G4



2.7

PSD comparison

RA ≠ RB nA = nB GA=GB

RA=RB nA=nB GA≠GB

RA=RB nA ≠ nB GA=GB

RA=RB nA ≠ nB GA=GB

Data: S. Bouhtiyya – Z. Silvestri



Roughness determination

35

Ro

ug

hn

ess (

nm

)

Roughness determined on f=[0,1 - 2,7µm-1]

Roughness (

nm

)

Samples

Roughness determined on two spatial frequencies domains

1: f = 0.1 – 1 µm-1

2: f =1 - 2,7 µm-1

Data: S. Bouhtiyya – Z. Silvestri



Comparison scatterometer - CSI

0

20

40

60

80

100

120

140

160

Native Si [Si] R3 n1 G4 [Si] R3 n2 G4 [Si] R2 n2 G3 [Si] R1 n2 G3 [Si] R1 n1 G1 [Si] R1 n2 G1

Ro

ug

hn

ess (

nm

)

Samples

Roughness determined on f=[0,1 - 2,7µm-1]

0

50

100

150

200

250

300

350

400

450

500

R3n1G4 R3n2G4 R2n2G3 R1n2G3 R1n1G1 R1n2G1

Sq

(n

m)

RMS Roughness Sq from CSI 160x120 µm

Documents

WP2: Gloss - xD Reflect2nde progress meeting of xDReflect MIKES — Espoo, Finland — 23th June 2014 WP2: Gloss Solid angle of illumination and detection (T3) Specular peak area (T4)