You might recognize TDK from their D-C180 audio cassette, VHS-C video cassettes, or their recordable DVDs. Nowadays, TDK is creating some very interesting technology that many people might not be aware of that they use every day.
In this article, we will break down two piezo actuators, devices that convert an electrical signal into an accurately controlled physical displacement.
EPCOS PowerHap™ Actuators
With TDK's unrivaled performance of force, speed, and response time, the PowerHap Actuators can provide an unprecedented quality of haptic feedback. The PowerHap utilizes multilayer piezo plates with migration-free copper inner electrodes. The actuators can be driven with relatively low operating voltages up to 60 V or 120 V, depending on the type. When the actuator is activated, the piezo plates only expand a nominal amount in the z-axis.
Due to the constant volume of the piezoelectric effect, however, the plate contacts simultaneously in both the x- and y-axis. An interesting addition to the new component is that it utilizes cymbals on both sides of the piezo plate as levers which allow the contraction in the z-axis to be amplified to a factor of 15.
Below are some of the key technical data on the PowerHap Actuator line.
|Type||Dimensions [mm]||Rated Voltage [V]||Expected acceleration* [g]||Max. Force [N]||Max. displacement [µm]|
|2.5G||9.0 x 9.0 x 1.25||0 to 60||2.5||5||35|
|7G||12.7 x 12.7 x 1.9||0 to 120||7||10||65|
|15G||26 x 26 x 2.4||0 to 120||15||20||>200|
* 100 gram load (data courtesy of TDK)
- Large displacement
- High acceleration
- High force
- Low insertion height
- Fast response time
- integrated sensor functionality
- RoHS-compatible PZT (lead zirconium titanate) ceramic
- Copper inner electrodes
- Titanium cymbals for displacement amplification
- Contains SVHC substance 12626-81-2
TDK is focusing on enhancing the sensory experience of Human-Machine Interfaces (HMIs) as well as engaging a full range of tactile sensitivity. Generally speaking, there are three well-known technologies that are used in haptic HMIs: eccentric rotary mass (ERM), linear resonant actuators (LRA), and piezo disks and benders.
Of the three, PowerHap provides the fastest response time of <1ms, with a low energy consumption of 1 mJ to 8 mJ, depending on the type. Focusing on the later of the three mentioned, there's a very broad application spectrum; PowerHap Actuator's main applications are vehicles, smartphones and tablets, household appliances, ATMs and vending machines, game controllers, and industrial equipment and medical devices.
Using Automotive vehicles as an example, piezoelectric actuators could be incorporated several different ways. The very precise mechanical movement the actuator provides is called a stroke; a stroke could be used to finely adjust mirrors and lenses as well as other components. The PowerHap could be used in pumps to control flow or even trigger a hydraulic valve.
TDK also has a PiezoHapt Actuator - PHU series that are very suitable for touch panels and displays. Utilizing piezo actuators that provide superior haptic feedback would help provide a larger dimension of usage in touchscreen devices as well as improving HMI interactions. Another large use would be to help assist the visually impaired navigate through various touchscreen displays.