Bio-Rad eBook - 2019 - 17

Meet the Innovators...
sources-extremely stable. Lasers can suffer from
speckle problems. But the biggest advantage of
LEDs is the sheer amount of power you can get
from these devices. When we started the project, we
didn't know if we could achieve the performance of a
laser scanner, but by the end of the project, everyone
was very happy with the performance comparisons.
Were there other special challenges in developing
this multifunctional imaging system?
With a camera-based imaging system, filtering
is challenging. You have light coming in from all
different angles, you have this big image sensor that
you have to protect from all this stray light. Our firstgeneration product, the older ChemiDoc, used only
one layer of filtering, just a filter in front of the lens.
For this new instrument, we developed what I view
as four different levels of filtering. We have filters
behind the lens, we have a filter in front of the lens,
and lens itself acts as a spatial filter, which filters out
all the highly off-angle light and parasitic light. So
we have a lot more sophisticated filtering in this new
product, and it really is what enabled us to get good
performance in the near-infrared in particular.
How did you source and select the camera
and filter components?
One of the unique requirements for the camera in
this system was our filter positioning. You cannot just
go and get a commercial off-the-shelf camera that
is capable of doing the things we need to do for our
imaging system. Our requirements were complex
enough that we needed to have a custom lens
developed for us.
What benefits did custom camera
development bring?
One of the nice things about going custom was
that we could make the resolution a bit higher than
what we could find from off-the-shelf lenses. We

could also optimize the lens coatings-antireflection
coatings-which is important to get the most light
through the lens. We did some specialty coatings
that you wouldn't find in a standard lens; we coated
the inside of the lens with special black materials
that mitigate some of the parasitic stray light that
can bounce within lenses. It basically helps reduce
the optical background levels that you see. l

Kevin McDonald

Kevin McDonald, PhD, Senior Staff Scientist,
Life Science Research, Bio-Rad Laboratories

"There was always one goal with
the ChemiDoc MP imaging project:
to make the best imaging system in
the world."
What is your role at Bio-Rad?
I'm a cell biologist by training. I've been at
Bio-Rad working on imaging projects since 2001.
In developing imaging systems, we really have to
know what the customer needs are, so I try to
keep my finger on the pulse of all the new

Bio-Rad eBook - 2019

Table of Contents for the Digital Edition of Bio-Rad eBook - 2019