Improving Lidar Signal Reflection using Functional Black ... · have developed Lidar angle...

Improving Lidar Signal Reflection using Functional Black Pigments

Color Reformulation Case Study

Contributors:Mike CrosbyScott Swain

Andre BendoDr, Paul Brown

Dr. Thomas FreyMichael Jakobi

Project Background

� At the 2016 Focus On Coatings Under Study conference, Ford challenged their coatings supply chain to improve both the solar and Lidar reflectivity of future production colors.

� Beyond potential auxiliary CAFE credits from higher TSR, the improvement of Lidar reflectivity would facilitate object detection and safety within future autonomous vehicle environments.

� Traditional carbon blacks strongly absorb in lidar’s NIR signal range.

� This study evaluates the impact of replacing traditional carbon black with functional black pigments in various coating layers on Lidar signal response.

2

Color Selection for Study

Color Selection Criteria� X<20% TSR� Remaining program life� Varied hues & lightness� Varied pigment types & loadings

3

Chart courtesy of: Ford Motor Company presentation, FOCUS 2016

Pigment % weight

PV 29 9.57P.Bk. 7 4.56PR 179 43.81

Fe2O3 Mica 23.73Fe2O3 Alumina 15.89

Fe2O3 Aluminum 2.45100

Pigment % weight

PB 60 64.92P.Bk. 7 7.55PB 15:1 8.15

Aluminum (18µ S$) 19.38100

Burgundy Velvet TCM7356 GRTEWHA R3

Color P/B = 0.20Hide = 16.5µ

Blue Jeans MetallicM7291 DDVEWHA N1


MagneticM7325 FM6EWHA J7


Pigment % weight

PB 60 2.30P.Bk 7 12.77PV 19 1.74

Alu+SiO2 (33µ CF) 25.75PB 15:3 0.45

TiO2 Mica 30.76Aluminum (18µ S$) 26.24

100

Basecoat Layer Control Pigmentation(All over Titanium Grey Primer)

4

� Variable: Loading of each Black Pigment to achieve Visual hiding

– 6hr Skandex pigment dispersion for uniform comparison– Carbon Black FW200 as Control– Paliogen® Black L 0086 NIR transparent perylene– Lumogen® Black K 0087 NIR transparent perylene– Sicopal® Black L 0095 NIR reflective mixed metal oxide

� System: E-coated steel panels, OEM SB Titanium primer / HSSB basecoats� Spray: Pneumatic� Color Match assessed but this was not the primary concern

Project Parameters

� Evaluate the contribution of each paint layer to Lidar signal response parameters. � Constant Parameters: Film Build, Visual Hiding, P/B ratio, Ratio of colored pigments

5

Pigment in: Primer_Basecoat

Deep Red Perylene Mica Shade Improved Lidar response from functional black pigments

Pigment % weight

PV 29 9.57P.Bk. 7 4.56PR 179 43.81

Fe2O3 Mica 23.73Fe2O3 Alumina 15.89

Fe2O3 Aluminum 2.45100

6

Spec

trop

hoto

met

er

Mea

sure

d To

tal

Carbon Black Control 19%

Reflective Black in BC 43%

Transparent Blacksin BC & Primer 51%

Common Lidar wavelengths

Burgundy Velvet – Encouraging resultsCarbon Black

Control

7

K 0087 Transparent

Black

• Total Lidar reflection doubled.

• TSR more than doubled, exceeding the 20% TSRCAFE target. Solar heat lamp evaluation confirmeda 20°F/15% reduction in heat build up.

• Color match goal, was very good.∆E’ = 0.8 for K0087 & 1.9 for L0086 even without altering non black pigment ratios at same P/B.

• But what about real world Lidar system visibility /signal reflection? It’s more complicated…

Burg Control: Burgundy Velvet TC 4.6% 15 19Burg 0086:0086 8.7% 31 51Burg 0086:0087 8.7% 30 51Burg 0086:0095 17.3% 29 43

Black PigmentationPrimer : Basecoat

Black Pigment Load for same

opacity

Total Solar Reflectance

%

Total 905nm Reflectance

(multi-angle) %

Lidar Specular & Diffuse Reflection Considerations• Traditional Lidar system point cloud density decreases with distance.

At 150 -200 meters away perhaps only a few Lidar points will hit surfaces of an oncoming vehicle. These are distances where 0.6g deceleration decisions could be made.

• Car surfaces are not flat and the points at which Lidar beams hit an object are rarely oriented at a perfect face angle. This is why both diffuse and specular reflections is important.

• Reflection from distant points on a target object must have sufficient returnsignal strength so the Lidar system can differentiate object presence fromambient NIR noise.

Lidar Source

Incident light

Diffusereflection

Specularreflection

8

• A Spectrophotometer measures total combined specular & diffuse NIR reflectance using a diffuse spherical collector dome to give a single reading from a panel at face orientation.

• OEMs recognizing point density erosion at distance & object incidence angle variance due to complex object geometries have developed Lidar angle dependent measurement methods.

• Ford historically used a 32 channel rotary Lidar unit to record 905 nm Lidar reflectance of painted panels rotated from 0º face to 30º & 60º flop angles.

• While increased reflectance is always welcome, a minimum 10% reflectivity at all angles is desired for object

‘visibility’ in various orientations & ambient conditions.

• For the colors studied, the high 0º specular reflectance was not an issue. It was at 30º & 60º flop angles at which lower diffuse signal return was inadequate for good object detection against ambient background NIR noise.

Pictures courtesy of: Ford Motor Company, FOCUS 2016

What should be measured? Signal reflection at various angles.

9

‘Conventional’ System (Primer + Basecoat + Clearcoat)

Sample1905nm Total Reflectance

2Lidar Aspecular Reflectance

Panel Angle 0° Panel Angle 30° Panel Angle 60°

Conventional formulation 19 % 70 % 4 % 1.5 %

Lidar managed formulation 51 % (2.7x) 98 % (1.4x) 27 % (6.8x) 17 % (11.3x)

1Measured using Perkin Elmer Lambda 950 Spectrophotometer (spherical collector)2Measured using Velodyne 32 channel Lidar system

Improving Lidar response through pigment formulation

Deep Red Mica Shade

10

Burgundy Velvet – Perylene / Mica / PV 19 ShadeResults and Comments� Replacement of carbon blacks with functional blacks dramatically

improved Lidar reflectance at all angles, exceeding targets.� The optimal Lidar formulation used transparent black L0086 in both the

basecoat and primer. � A base-coat only solution using reflective L0095 also exceeded reflectivity

targets.� TSR dramatically improved and Color match was very good considering only

black pigments were changed. � Carbon black even at low loading strongly absorbs the Lidar NIR signal.� A “fleet-wide functional primer-only solution” appears unfeasible. � Many automotive organic pigments are NIR transparent & can be used

over reflective primers.

11

Primer_Basecoat

Pigment % weight

PB 60 64.92P.Bk. 7 7.55PB 15:1 8.15

Aluminum (18µ S$) 19.38100

Blue Jeans MetallicM7291 DDVEWHA N1


Deep Blue indanthrone metallic shadeImproved Lidar response from functional black pigments

12

Blue Control: Blue Jeans Metallic 7.6 18 24Blue 0087:0086 14 26 40Blue 0087:0087 14 27 43Blue 0087:0095 14.9 26 38



opacity %

Total Solar Reflectance %


(multi-angle) %


Sample1Reflectance

905nm



Conventional formulation 24 % 75 % 5 % 2 %

Lidar managed formulation 43 % (1.8x) 88 % (1.2x) 18 % (3.6x) 8 % (4.0x)

1Measured using Perkin Elmer Lambda 950 Spectrophotometer2Measured using Lidar system


Medium-Dark Indanthrone Blue Metallic Shade

13

Blue Jeans – Indanthrone blue aluminum metallic Results and Comments

� Functional blacks improved Lidar response at all angles with problematic flop reflectance increasing by 360-400%.

� Reflective black L 0095 in the basecoat had highest 30º result but the transparent L 0086 BC provided the best critical 60º result falling just shy of target.

� In a bell spray production environment, lower flake alignment could further increase 60º reflectivity.

� Functional black formulations exceeded TSR targets. � Color match was not the goal but ∆E’ <2.0 vs initial 8% FW200 load with just one

PB 15 shading component this color position should be achievable.� Natural and synthetic micas tend to scatter NIR better on flop than aluminums,

therefore improving reflectance in flop. � Use of interference white or blue mica may improve flop reflectance in this 20%

aluminum S$ flake styling.

14

Primer_Basecoat

Deep Grey BasecoatInfluence of black pigment selection on Lidar performance

Pigment % weight

PB 60 2.30P.Bk. 7 12.77PV 19 1.74

Alu+SiO2 (33µ CF) 25.75PB 15:3 0.45

TiO2 Mica 30.76Aluminum (18µ S$) 26.24

100

Hide = 16.5µ

MagneticM7325 FM6EWHA J7

Color P/B = 0.081

15

Grey Control: Magnetic 12.8 27 29Grey 0086:0086 34.5 37 52Grey 0087:0087 22.7 40 55Grey 0087:0095 76.7 29 34



opacity %

Total Solar Reflectance %


(multi-angle) %


Sample1Reflectance

905nm



Conventional formulation 29% 85% 5% 1%

Lidar managed formulation 52% 100% (1.2x) 25% (5.0x) 14% (14.0x)



Bluish Medium Grey Effect Shade

16

Magnetic Grey – Dark Grey Aluminum Metallic■ Results and ►Pigment Formulation Commentary

� High loading of reflective black L 0095 in the basecoat and primer improved the problematic flop by 500-1400% to exceed all reflectance targets.

� Given the high aluminum (52%) and carbon black (13%) in the control, color varied substantially from control ∆E’ 2.6. Formulation optimization would be required.

� Aluminum effects tend to provide high reflectance in face but weaker reflectance on flop. Separate study finds that equivalently sized iron oxide colored Si$ and cornflake pigments (like Paliocrom) perform up to their naked aluminum counterparts.

� Aluminums are good radar reflectors for target objects but are poor radar transmitters so care is needed when coating radar emission / collection windows.

� Reformulating some aluminum with white micas should improve Lidar flop reflectance and improve radar transmission in similar stylings.

17

18

Titanium Grey Primer

Sample1Reflectance

905nm



Conventional formulation 21% 38% 26% 22%

Lidar managed formulation 49% 78% (2.0x) 57% (2.2x) 46% (2.1x)



Bluish Medium Grey Effect ShadeMedium

Grey Primer

Summary - Lidar Functional Formulation Conclusions� Using functional black pigments to replace carbon black in basecoats will

dramatically improve a color’s Lidar response. � Functional blacks also dramatically improved solar reflectance, potentially offering

benefits for future two tone roofs or hoods. � Lidar visible coatings are currently achievable in most color spaces with

appropriate pigment selection early in the design cycle. � The optimal choice of functional black pigments depends on color position

and reflectivity of other colored and effect pigments in the formulation. � For the automotive colors studied, Lidar reflectivity at flop angles was the

most challenging and necessitated angle dependent measurement. � Many organic pigments are NIR transparent & but inorganic transparency varies

widely.� Micas tend to provide better flop response than aluminums and colored

aluminums perform similarly to silver aluminums.

19

� Technical Support services including:– Color match assistance for existing and concept colors– Optimal functional pigment selection based on substrate, coating stack, and color– Predictive Lidar response modeling based on potential pigment formulations– Angle-dependent Lidar reflection measurement capability by end of 2019

� Industry leading in Lidar functional black pigments including transparent and reflective black pigments.

� Broadest range of pigments with known Lidar characteristics including:– Highest chroma organic pigments (which are largely transparent)– Numerous Inorganic chemistries (which vary depending on chemistry)– Iron oxide and interference pearlescent pigments based on synthetic or

natural mica, sourced at our wholly owned mine in Hartwell, USA.– Iron oxide coated aluminum effect pigments

How can BASF Colors & Effects support my Lidar functional styling developments?

20

For more information or support, please contact us…

AmericasBASF Colors & Effects USA LLC 24710 West Eleven Mile Road Southfield, MI 48034 USA

[email protected]

[email protected]

EMEABASF Colors & Effects GmbHAn der Rheinschanze 167059 Ludwigshafen Germany

[email protected]

[email protected]

Asia PacificBASF Colors & Effects Shanghai Ltd.No 300, Jiang Xin Sha Road 200137 Shanghai China

[email protected]@basf.com

21

Improving Lidar Signal Reflection using Functional Black ... · have developed Lidar angle...

Documents

Transcript of Improving Lidar Signal Reflection using Functional Black ... · have developed Lidar angle...