Murata Manufacturing Co Ltd developed a sensor device using a highly transparent organic piezoelectric film.
The film has the following three characteristics. First, its piezoelectric output constant is as high as 180 x 10-3Vm/N (g31 conversion). Second, its light transmittance is 98% or higher (according to the internal haze measurement). Third, it does not have pyroelectricity. Its dielectric constant is 2.5.
Murata will start to ship samples of a displacement sensor and touch panel that use the newly-developed piezoelectric film in the spring and fall of 2012, respectively. The film is targeted at smartphones, tablet computers, portable game consoles, etc, which require intuitive user interfaces.
To have pyroelectricity, existing piezoelectric films cannot detect temperature and bend/twist separately. But Murata developed a highly transparent piezoelectric substance that does not have pyroelectricity in collaboration with Kansai University and Mitsui Chemicals Inc.
Furthermore, by applying the new piezoelectric film, it developed the "Leaf Grip Remote Controller," a remote that enables to control a TV by bending or twisting the remote, and the "Touch Pressure Pad," a touch panel that can measure pressure strength.
Leaf Grip Remote Controller
The Leaf Grip Remote Controller uses two piezoelectric films: one for detecting bends and the other for detecting twists. It is a new type of remote that can be operated by bending and twisting a plate. Equipped with photoelectric cells, whose dye emits electrons when receiving light, the remote can be operated without a battery.
Touch Pressure Pad
The Touch Pressure Pad is a touch panel to be connected to a PC, etc. Its piezoelectric film does not have pyroelectricity and does not generate voltage just by being touched by hand. Therefore, its detection error is small, Murata said.
Also, the touch panel can not only detect vertical and horizontal finger movements but also measure pressure strength. For example, it is possible to enlarge an image at a high speed by pressing the panel firmly and at a low speed by pressing it lightly.
Murata will exhibit and demonstrate those devices at CEATEC Japan 2011, which will take place from Oct 4, 2011, in Chiba Prefecture, Japan. It has applied for about 30 patents related to the new material and devices.