Article published on juin 2008Laser environments
Virtual vision ensures 100% safety
Laser protection goggles that filter out all wavelengths and energy levels while maintaining clear visibility: a CEA/DAM* team has achieved this using a virtual vision device equipped with two miniature cameras. The device can be adapted for other applications, such as arc welding.
Jean-François Demonchy,
researcher at CEA/DAM, has
designed the invention based
on innovative technologies. The
invention (patent application
in progress) combines various
elements (virtual vision goggles,
miniature CCD cameras, headband,
audio and video connectors)
to offer a 100% safe solution for
persons working in laser environments.
It can be extended to other
hostile luminous environments.
'No conventional laser goggles
cover all wavelengths and energy
levels', recalls Jean-François
Demonchy. 'When a laboratory
comprises several laser systems,
two or even three different pairs
of goggles need to be used'. In
addition, such goggles must be
regularly tested to ensure optimal
efficiency.
With virtual vision, these disadvantages
are eliminated. The scene
is no longer viewed directly with
the eye. Instead, it is retransmitted
by two CCD cameras located in
the upper part of the device and
displayed on an integrated screen.
'The equipment chosen provides
a high-resolution and large-size
image, equivalent to a 40-inch
screen viewed from a distance of
2 meters', explains Jean-François
Demonchy.
Another advantage of virtual vision
is that the laser beam remains
visible whereas, by definition,
filtering goggles cause it to 'disappear',
along with much of the
visible spectrum. Such situations
may lead workers to remove their
protective goggles, a reflex action
that all safety managers actively
discourage (for example, when
performing adjustments requiring
fine alignment of the laser beam!).
With virtual vision, there is no
longer a reason for this to happen.
The cameras can be selected to
reproduce wavelengths invisible
to the human eye, such as infrared
wavelengths, and thereby extend
the scope of application to other
work environments potentially
harmful to the eyes.
The CEA team perfecting the device
is currently completing a second
prototype. Light (200 grams),
powered by a lithium-ion battery
with 5 hours of autonomy, it will
be used routinely in the Megajoule
laser facility laboratories near
Bordeaux: 'After optimisation, we should achieve a cost equivalent
to or slightly higher than that of
conventional filtering goggles',
explains Jean-François Demonchy,
'But our device will replace several
goggles and will require no maintenance,
whereas filter quality tests
alone are very expensive'.
The CEA team is currently searching
for a partner for the industrialisation
and marketing phase.
Moreover, the invention can serve
as the basis for more sophisticated
functions: image transfer to a
control centre for monitoring
delicate operations, display of a
procedure or virtual scene superposed
on the screen (augmented
reality) to assist an operator, etc.
Not to mention situations such
as arc welding, where the glare
would no longer compromise sight
quality.
* Military applications division
