Fat Finger Syndrome Solution Found
with Finite Element Analysis
Samsung employs realistic simulation to
design mobile device keypads for fewer typos
by: Soo Hyun Park
Anyone who’s ever typed on a computer
keyboard or mobile device keypad has
experienced this: While aiming for one letter,
you hit a different one on a nearby key. The result? Poor spelling, mangled messaging, an email you
never should have sent.
As electronic devices and instrumentation
become increasingly compact, the
search for a cure for “fat finger syndrome,” as it is known in the industry, is becoming ever
more urgent. Flat touch screens operated by pressure sensors may be taking over tablet computers and smart phones, but
keypads and keyboards are still widely
used in many electronic devices. Desktop computers,
laptops, some cell phones, remote controls, and appliances, such as washing machines and
dryers, all still rely on the touch of
a finger on a spring-loaded key.
At the Global Production Technology Center
of Samsung Co., Ltd. in Suwon, Korea,
engineers strive to stay ahead of the trends toward tinier keys and denser key
layouts with each new model. “We are working to make products both smaller and
easier to use,” says Soo Hyun Park, Manufacturing Core Technology Team, Global
Production Technology Center at Samsung, “so we want to reduce
the amount of mistyping that can occur on
the more compact keypads.”
Samsung engineers decided to delve deeper
into the fat finger phenomenon by examining the physics behind keystrokes,
finger pressure, and strike angle to
determine what can go wrong and how to
make it happen less often. “Since keyboards will remain widely in use for the foreseeable future,
we will continue to study the physical
user interface to better understand the ergonomics of human-device interaction,” says Park. Using
Abaqus finite element analysis (FEA), they were able to cut mistyping errors
from 35% to 7% with an intermediate prototype model of a QWERTY keypad, so
named for the sequence of letters that run left to right on a standard type-key
layout.
Realistic simulation of the interaction
between human fingertips and device keys enabled Park’s team to identify the
variables that lead to mistyping. “By systematically modifying the relevant
design parameters, we could see which keypad configurations led to the least
number of typing errors,” he says.