Color Filtering using Polystyrene Microspheres Sachin Mehta Reno Nevada

1. Revolutionary Color
Filtering Using Fluorescent
Polystyrene Beads
Brian Gallaspy Alan Pham
Huayu Zhou Sachin Mehta
Reno, Nevada

2. Introduction
• Using solutions polystyrene beads of the following colors: red, blue, and green
we will print 5mm x 5mm squares on glass cover slips. We were previously
printing on photo-paper, but Alan here will discuss more about that and why we
made this change.
• Various combinations will be printed—layer on top of layer. For example, some
of the combinations:
• Red Blue Green
Red Green Red
Green OR Red OR Blue
Green Blue
• These combinations, when analyzed using Photo-Luminescence
Spectrometer from Ocean Optics, will result in different spectrums and
wavelengths.
• The variable is the amount of layers of a certain color we put in a
sample.
• These wavelengths will then be plotted on the C.I.E Chromaticity
Diagram System.

3. • These molecules are
capable of absorbing
energy from photons (UV,
vis.)
• Energy is absorbed by
electron moving to
unstable “excited state”
• When the electron
relaxes to its ground state,
energy is released as a
photon corresponding to
the difference in energy
between the excited &
ground state.
Photoluminescence
• Molecules that fluoresce
contain conjugated π-
bonds
• This means that the
molecule has a structure
that has alternating single
and double bonds
• This structure allows
electrons to be shared
throughout the whole
molecule, and energy
states that are conducive
to fluorescence.

4. Fluorescent Polystyrene Microspheres
• Polystyrene is a widely
used polymer of the
monomer styrene.
• It can be made into
spheres ranging from
1μm – 1mm.
• Upon these spheres,
fluorescent
compounds are
attached. http://www.lifetechnologies.com/us/en/home/life-science/cell-analysis/qdots-microspheres-
nanospheres/fluorescent-microspheres.html

5. C.I.E 1931 Color Space
 Links physical pure colors
(wavelengths) & perceived color
of the human eye
 Three ‘primary’ colors—red, blue,
and green
 Characterizes colors by a
luminance parameter Y and a
two-coordinate x,y system—
which specifies any single point
on the chromaticity diagram to
the right
 The various color combinations
printed one on top of another will
allow us to develop our own
Chromaticity Color Triangle
http://www.color-theory-phenomena.nl/10.03.htm

6. Coordinates of Pure White
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/cie.html
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/photom.html#c2

7. Methodology
 The data points from the PLS
will then be inputted into a
Matlab Program to yield a
charted color map with the
color’s specific coordinates.
 After obtaining data
coordinates from multiple
samples we applied
multivariate regression to
obtain a ratio analysis.
 With the newly obtained
ratios, it was then possible to
mix the respective amounts of
polystyrene beads to try and
achieve the desired
coordinates for the color white
x, y = (1/3, 1/3).
 Using the Dimatix 2D inkjet
printer, multiple layers of the
fluorescent microspheres are
printed onto a glass slide.
 Varying layers of the three
different fluoresced
microspheres will yield a unique
respective position on the C.I.E
Color Space.
 Each sample will then be
analyzed with the assistance of
Dr. Zhou, and a Photo-
Luminescence Spectrometer by
Ocean Optics.

8. Results – Pure Color Blue
Matlab Output of Chromaticity of Blue Polystyrene Microspheres

9. Results – Pure Color Green
Matlab Output of Chromaticity of Green Polystyrene Microspheres

10. Results – Pure Color Red
Matlab Output of Chromaticity of Red Polystyrene Microspheres

11. Results – Data Set I

12. Sample # 3 Analysis – 8 Green Layers
and 1 Red Layer
Matlab Output of Chromaticity of Most Precise Sample from Data
Set I

13. Results – Data Set II

14. Sample # 12 Analysis – 5 Red Layers, 10
Green Layers, & 5 Blue Layers
Matlab Output of Chromaticity of Most Precise Sample from Data
Set II

15. Unforeseen Problems
- For first attempts in data selection we
implemented 1 in x 1 in cut cover class.
• These slides were un-treated and not
cleansed—leaving us to question the
validity of our samples.
• Thickness of these glass slides were 1.2 mm
which brought extraneous light into our
samples when analyzing using the Photo-
Luminescence Spectrometer.
- Printer temperature settings had
to be adjusted in order to obtain
most reliable printing.
- Waveform manipulation was not
constant for each time we
printed. For example, after
changing out the printer
cartridge to another solution of
polystyrene beads we would not
obtain proper printing.
- Nozzle Clogging—sometimes
leaving us with only one nozzle
to work with. This added on
extra, and wasted time, that
could have been used to
perform more valuable analyses.

16. Applications
 The color white, as we know it, is
not in the true sense white.
 It lacks “purity”– in regards to
being at the exact coordinates of
(1/3, 1/3).
 Major research is taking place as
we speak to obtain this pure color
and leading companies such as
Samsung and Sony are at the
forefront.
 Determining the exact ratio of
blue : red : green would make it
possible to advance optics,
engineering, and technology.
http://www.venturelighting.com/naturalwhite/naturalwhite_faqs.html

17. Thank you!
Now we will
leave the floor
open to any
questions!