Electroactive polymers can now be used in controllers for
gaming devices, allowing users to feel mechanical movements that correspond to
actions in the game.
"The gaming industry is showing tremendous interest to start
introducing this to bring a new level of reality to games," says Dirk
Schapeler, CEO, Artificial Muscle,
Inc. of Sunnyvale, CA.
Gamers can feel dice rolling around, simulating action on a
screen or feel a tactile sensation when a ball hits a wall or falls into the
holes of a labyrinth. The devices are called "haptic" actuators, referring to
sense of tough transferred to a user.
The technology is based on a thin layer of dielectric
polymer film placed between two conductive electrodes. A voltage is applied
across the electrodes, causing the electrodes to attract each other. This triggers
a contraction in thickness and expansion in surface area. The electrical energy
is transformed into mechanical movement without any friction losses, such as
those in electromagnetic motors, enabling the design of highly energy-efficient
Forty-six patents have been issued to cover the technology.
One of the early patents
describes how electroactive polymers can be pre-strained more than 200 percent to
improve conversion from electrical to mechanical energy. The polymers are
pre-strained via mechanical stretching.
The technology was developed by scientists at SRI
International who say they began looking at pre-strained electroactive polymers
because of cost or mechanical limitations with other materials than can transform
electrical energy to mechanical energy. These include piezoelectric ceramics,
such as lead zirconium titanate (PZT).
Key properties for polymers that work well as dielectric
elastomers are high electrical breakdown strength, a low modulus of elasticity for
large or small deformations and a high dielectric constant.
Polymers described as suitable by SRI in another patent
are CF19-2186 silicones from NuSil Technology; HS3 silicones from Dow Corning and
4900 VHB acrylics from 3M Corp.
One of the most common applications for electroactive polymers
is in robots. That's why the technology is often referred to as artificial
muscles. They can also be used as actuators and sensors in other fields, such
as small pumps in medical devices.
SRI spun out its technology into Artificial Muscle Inc. in
2004. The company was acquired by Bayer MaterialScience in March because
commercialization will require development of high-performance film
manufacturing technology, a specialty of Bayer MaterialScience.
About two years ago, Artificial Muscle began to leverage its
technology to create the Reflex brand of haptic actuators which target consumer
electronics including smartphones and other portable electronics, computer
peripherals, gaming controllers, touchpads, POS kiosks, industrial controls and
casino gaming machines.
AMI offers two versions: a Moving Touch Sensor Design and a
Battery Shaker Design. The Moving Touch Sensor Design uses a Reflex HIC
Actuator to provide a direct tactile response to the user by moving the touch
surface. The HIC can be mounted to the back of the touch sensor or the LCD. The
thin profile is designed to add minimal thickness to the LCD and touchscreen
The Battery Shaker Design uses a Reflex HIC Actuator to move
the battery as a mass to provide feedback that can be felt in a user's hand.
This provides the same haptic feedback as the Moving Touch Sensor design, but
does not require the complexity of external moving parts.
"Industry research indicates that gamers place greater value
on haptics in games with more high-fidelity effects per second," Schapeler
says. "With our technology you can do more than just button clicks, you can
create a realistic feeling into games to heighten the user experience."