Ideal Star Inc.

Daikin Industries, Ltd.

Other

Hiroji Ohigashi

Kenji Omote

Meiten Koh

Yuuki Kuwajima

Takashi Kanemura

Tetsuhiro Kodani

Eri Mukai

Tsurugi Samezawa

An object of the present invention is to improve the piezoelectricity of a PVT having the VDF ratio of 82 to 90% represented by a copolymer, in which copolymerization of vinylidene fluoride VDF and trifluoroethylene TrFe is 85 versus 15 (this is written as PVT85/15, and which is excellent in resistance to deformation, and heat resistance, etc. And therefore, it is also to obtain a piezoelectric film having piezoelectricity exceeding a PVT of less than 82 mol % of VDF represented by a PVT75/25, which conventionally shows the highest piezoelectricity, and a method of producing the same. A piezoelectric film is made of a mixture of two kinds (for example, a first copolymer is PVT85/15 and a second copolymer is PVT75/25) having different polymerization ratios of vinylidene fluoride VDF and trifluoroethylene TrFE.

Piezoelectric film and method for producing same

A piezoelectric film which is better in heat and deformation resistant properties than those in the prior art is provided along with a method of manufacture. The film is a piezoelectric film that is composed of a copolymer of vinylidene fluoride and trifluoroethylene, the copolymer having a content of vinylidene fluoride in a range of not less than 82 mol % and not more than 86 mol % and having a molecular weight not less than 600,000. The piezoelectric film is subjected to a heat treatment for crystallization of the copolymer at a temperature ranging from not less than 140&#xb0; C. to not more than 150&#xb0; C., and is thereby caused to develop piezoelectric property. The piezoelectric film further has a heat resistance of not less than 140&#xb0; C. and a breaking distortion of not less than 8% and not more than 55%, and an excellent deformation resistant property.

Piezoelectric film and process for producing same

A transparent piezoelectric sheet-with-a-frame includes a transparent piezoelectric sheet and a frame covering a peripheral edge portion of the transparent piezoelectric sheet. The transparent piezoelectric sheet includes one transparent piezoelectric film including an organic polymer, one first transparent plate electrode placed on a first main surface of the transparent piezoelectric film and having a first transparent plate electrode portion, and one second transparent plate electrode placed on a second main surface of the transparent piezoelectric film and having a second transparent plate electrode portion. An outline of the second transparent plate electrode portion is positioned inside an outline of the first transparent plate electrode portion as seen in a plan view. The outline of the first transparent plate electrode portion completely coincides with the frame, and the outline of the second transparent plate electrode portion does not at all coincide with the frame as seen in the plan view.

Transparent piezoelectric sheet-with-A-frame, touch panel, and electronic device each having the transparent piezoelectric sheet

A transparent piezoelectric sheet includes a quadrilateral-shaped transparent piezoelectric film and a first transparent plate electrode. The quadrilateral-shaped transparent piezoelectric film includes an organic polymer. The quadrilateral-shaped transparent piezoelectric film has entire main surfaces that are piezoelectric. The first transparent plate electrode is layered on part of a first main surface of the main surfaces of the transparent piezoelectric film. One to three sides of the four sides of the quadrilateral shape of the transparent piezoelectric film and area(s) of the first main surface adjacent thereto are not covered by the first transparent plate electrode.

Transparent piezoelectric sheet, and transparent piezoelectric sheet-with-a-frame, touch panel, and electronic device each having the transparent piezoelectric sheet

Growing community of inventors

Sendai, Japan

Hiroji Ohigashi