Portable microscopes are used for circuit board inspection, as seen here using 20 magnification. Image
courtesy of Celestron.
configuration enhances the microscope’s
capabilities, he said. “We can actually
create oblique lighting with the touch of
a button to help create shadows to capture
the texture on the surface.”
Upon closer inspection
The portability of handheld microscopes
plays a key role in their use for product inspection and quality assurance. In the case
of work done at NASA’s Langley Research
Center in Hampton, Va., portability and
depth of field were important reasons for
using a Keyence handheld microscope.
Margaret Holloman, a NASA quality
assurance specialist, was charged with
determining the exact profile of a nose
cone studded with a large number of
flush-mounted pressure gauges. Engineers
wanted the instruments to gather data in
flight and needed to know the relationship
of each gauge to its surroundings.
The situation demanded certain capabilities, Holloman said. “Making noncontact
measurements as well as being able to
take 3-D images was crucial.”
A conventional microscope couldn’t
handle the approximately 3-ft-wide by 6-ft-
long wedge-shaped nose cone. In addition,
a standard microscope lacks the depth of
field necessary for the angled point of view
required to determine heights accurately. So
Holloman modified a heavy-duty camera
tripod and mounted a handheld microscope
on it, thereby obtaining the needed 3-D
measurements. She also captured a permanent record of the depth and contour of
each pressure gauge and its relationship
to its surroundings.
Although the nose cone project is done,
the system is still in use, with the depth of
field an important advantage. “There are
times that researchers request complex
geometries be measured on a wide variety
of flight hardware,” Holloman said.
A final example of handheld microscopy
comes from Celestron. Known as a telescope maker, Celestron entered the
microscope market with a new line of products last year, part of an effort to increase
the company’s revenues in this area. One of
the items was a handheld microscope capable of 150 magnification. It has a 1.3-
megapixel digital camera and connects to a
computer through a USB port.
Unlike some other handheld microscopes, Celestron’s products are aimed
at consumers and hobbyists. Some of the
uses there include inspection of coins,
stamps and other collectibles. There are
also both formal and informal educational
uses for these handheld microscopes. As
with similar products, Celestron’s devices
have found application in industrial settings, noted Alan Hale, the company’s vice
president of product development.
At Celestron itself, occasional problems
with a circuit board have led to an examination using the company’s own products.
In those cases, the portability of the microscope was important in that the inspection
could occur in place.
Equally important, though, was the device’s ability to make the information visible. It thereby rendered something that was
physically small, but that in manufacturing
was having a large impact, big enough for a
group to diagnose and fix. Recalling the situation, Hale said, “We’ve had three or four
engineers standing around, looking at this
thing on the screen.”