murakami - Avian Optics and Spectroscopy Group

Color Research Laboratory
11-3 Kachidoki 3-Chome Chuo-Ku Tokyo 104 Japan
Tel: +81 3 3532 3011
Fax: +81 3 3532 2056
GSP-1 Main
System Overview
The colour and surface appearance of materials illustrated by pearlescent paint, changes
depending on the incident and viewing angles of the light.. This phenomenon is commonly called
the “Flop Effect”.
The GCMS-3 GonioSpectrophotometric Colour Measurement System permits the user to
automatically vary the incident and viewing angles over a broad range, thus building a multi-angle
reflectance profile for the specimen under evaluation.
The system comprises the GSP-1 Optical Measurement Unit operated in conjunction with
GCMS-Win Software running on a Windows™-based PC. The GSP-1 optical sensor features a
true dual-beam design wherein the reflectance from the specimen is compared continuously
against that of a reference plate. This offers very high stability and measurement precision. This
facility also provides automatic correction for the variation in intensity, and the area of illumination
/ viewing, as a consequence of rotating the specimen in the light path. The GSP-1 features a highspeed detection system to derive spectral information, which reduces the measurement time
particularly at high angular resolutions.
The GCMS-Win Software is an interractive package allowing the user to create defined setups to
speed up routine and repetitive tests. In each named setup, the measurement mode, incident
angle and receiving angle range may be entered with a selection of spectral and tristimulus data
tables, and a wide range of graphical displays illustrating the colorimetric distribution.
Avian Group USA/ P.O. Box 822/Wilmington.Ohio 45177 USA
Ph: 937-655-8767/Fx:937-655-8765
Page 1
Data may be readily transferred from GCMS-Win into other Windows-based software applications
such as spreadsheets, for further analysis. Data is captured from the GSP-1 sensor unit and
stored in spectral form which enables the user to alter the colour scale, illuminant and observer
function retrospectively, without the need to re-measure the sample.
The software automatically detects a connection to the GSP-1 and if not present, enters “data
recall” mode – data files stored in the PC may be re-opened for further processing and display.
The GCMS-3 is suitable for evaluating the angular colour and lightness distribution of a wide
range of materials including:
Pearl-mica and metallic paints
Anodised and metallised coatings and inks
Hair treatments – colorants and conditioners
Coated Glass
Retro-reflective, coated and pearl-effect textiles
Lquid-crystal displays
Avian Group USA/ P.O. Box 822/Wilmington.Ohio 45177 USA
Ph: 937-655-8767/Fx:937-655-8765
Page 2
GSP-1 Optical Measurement Unit – Principle of Operation
The sample to be measured (5) is clamped into place on the sample stage with manuallyadjustable tilt (“flapping”) angle (3). This stage accepts samples up to 195 x 220 mm and has a
broad aperture to allow a wide range of incident and viewing angles. Fine adjustment of the
flapping angle can be made by the micrometer assembly (4). During calibration, the sample is
replaced by a barium sulphate-coated white standard plate.
The reference white plate (6), similarly barium sulphate-coated, is positioned in its receptacle and
remains in place throughout routine measurements.
The entire sample platform (2) rotates in accordance with the parameter settings made in the
software, between limits of -80° and +80° from the normal (perpendicular to the sample plane).
The lamp housing (1) incorporates a single tungsten halogen source lamp which is divided into
two identical beams via mirrors, lenses and heat filters. The sample beam (1S) and reference
beam (1R) exit through apertures. The lamp housing rotates on the same axis as the sample
platform to provide a variable incident angle, again within the range of ± 80° from the normal.
The light reflected from the sample, and that from the reference white plate enter the sample
receptor (7S) and reference receptor (7R) respectively. Each beam is directed to the fixed
detection system via a mirror and through a beam chopper assembly. The chopper alternately
directs the reference beam and the sample beam to the monochromator via a lens system.
The light from the monochromator is dispersed into each wavelength via a diffraction grating and
then is photoelectrically converted by the elements of a photodiode array. The electrical signals
are amplified by a wavelenth-independent amplifier, transformed to digital signals by an A/D
converter, and then transmitted to the PC via a GP-IB IEEE interface for processing into the userselected colour scales and displays.
Avian Group USA/ P.O. Box 822/Wilmington.Ohio 45177 USA
Ph: 937-655-8767/Fx:937-655-8765
Page 3
The raw data comprises spectral reflectance and angular locus of the lamp housing and sample
stage relative to the fixed detector.
In the case of highly-reflective or glossy sample surfaces, the light reflected from the sample
close to the specular angle may approach the saturation level of the detection system. To
counteract this, the sample and reference receptors incorporate a filter wheel. A series of neutraldensity (mesh) filters are automatically introduced into the receptor light path until the detection
system is no longer light-saturated. The reflectance data is then compensated by the
transmittance of the appropriate filter used.
Below is a functional schematic:
Filter wheel
Fixed Detector Housing
Flapping angle δ°
angle R°
angle I °
Diode Array
Reference plate
(barium sulphate)
Lamp housing /
beam splitter
Setting I° + R°
Sample Stage and Lamp
Housing Common
Rotational Axis
Avian Group USA/ P.O. Box 822/Wilmington.Ohio 45177 USA
Ph: 937-655-8767/Fx:937-655-8765
Page 4
Setting R°
GSP-1 Optical Sensor Unit
Measurement System
Dual-Beam Optics with Reference Plate
Light Source
12V 100W Halogen Lamp
Lamp Life
1000 hrs Nominal
Concave Diffraction Grating
Silicon Photodiode Array
Wavelength Range
390 – 730 nm
Wavelength Interval
10 nm
Spectral Bandpass
approx. 10 nm
Wavelength Accuracy
± 1 nm @ 560nm
Wavelength Repeatability
± 0.1 nm
Measurement Ranges:
Incident (illumination) Angle
- 80º to + 80º
Receiving (viewing) Angle
- 80° to + 80°
(except when incident angle + receiving angle ≤ 12° as lamp housing obstructs receptor)
Angular Accuracy
within ± 0.5°
Angular Resolution
0.1° (resolution of absolute encoder)
Viewed Area
approx. 8 x 16 mm at 0° receiving angle
approx. 8 x 94mm at 80° receiving angle
(with flapping angle = 0°)
Aperture Angles:
Source image angle
Receptor aperture
± 1.05° in plane of measurement
± 2.10° perpendicular to plane of measurement
± 1° in circle
Neutral Density Filter Range
Reduces sample to 30, 10, 3, 1, 0.3, 0.1, or 0.03%
Measurement Duration
approx. 3 seconds per angle increment
Measurement Accuracy
within ± 0.5%
0.05% SD ( white tile measured 45°/0° at 560nm)
Dimensions (mm) / Weight
566 (W) x 972 (D) x 922 (H) / 86kg
Power Requirements
100V AC, 50/60 Hz, 4A (for Europe, 220 - 240V AC,
1KVA transformer recommended)
Computer Interface
GP-IB (PC) F by Contec Ltd
Avian Group USA/ P.O. Box 822/Wilmington.Ohio 45177 USA
Ph: 937-655-8767/Fx:937-655-8765
Page 5
GCMS-Win Software
Tool Bar Functions
Begin, Pause or Continue Measurement Sequence
Select and Configure Colour Scales and Graphical Displays
Begin Screen Output of Measured or Stored Data
Print Pre-Selected Display Windows
Manually Store Data in User-Specified File
Menu Functions
Colour Difference
Measurement menu
Open Saved Data File, Save Setups, File Conversion, Quit
Global , Screen Display, Printer, Sensor and Calibration Data
Selecting Product Standards
Execute using White Reference Tile, Enter New Cal. Tile Data.
Measurement Mode selection
R-Scan - Incident and Inclination (Flapping) angles fixed
I -Scan - Receiving and Flapping angles fixed
F-Scan – Incident and Receiving angles fixed
Selection of
Incident angle or range and increment size
Receiving angle or range and increment size
Flapping angle or range and increment size
Saving as Named Measurement Setup
Tile, Cascade, Arrange
Lamp Setup and Diagnostic Functions
Colorimetric Calculations
Spectral Reflectance
Colour Scales
Observer Functions
Radiance Factor (%) , 10nm Intervals, 390 – 730 nm
CIE XYZ, CIE L*a*b*,C*ab, h* ab, Yxy,Hunter Lab, CIE L*U*V*, AN-40
A, C, D65, D50, D55, D75, F
2°, 10°
Tabular and Graphical Displays
Data Tables
Spectral Distribution v. Angle ( I, R, F )
Tristimulus Data (user-defined)
(auto or manual scaling)
Spectral Distribution v. Angle ( 2-D )
Spectral Distribution v. Angle ( 3-D )
L,a,b Change v. Angle ( 2-D )
ab Chromaticity Change v. Angle ( 3-D animated )
xy Chromaticity Change v. Angle ( 2-D )
Optional Data v. Angle ( 2-D , XY and Polar )
( Right-hand mouse button opens COPY / PASTE menu selection to other Windows applications )
Computer Requirements
Pentium™ 433 or higher
64Mb Ram or higher
100Mb free hard disk space
17in SVGA monitor or larger recommended, > 32,000 colours
1 free ISA / PCI card slot
Windows™ 95 or 98 (NT4.0 in future)
Avian Group USA/ P.O. Box 822/Wilmington.Ohio 45177 USA
Ph: 937-655-8767/Fx:937-655-8765
Page 6
Examples of GCMS-Win Screen Displays
Avian Group USA/ P.O. Box 822/Wilmington.Ohio 45177 USA
Ph: 937-655-8767/Fx:937-655-8765
Page 7
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