The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 05, 1990
Filed:
Sep. 01, 1988
Kyung T Park, Berwyn, PA (US);
Pennwalt Corporation, Philadelphia, PA (US);
Abstract
An electrostatic image display apparatus which uses piezoelectric film to enable a user to form images on a screen. The apparatus is contained within a housing. Supported within the housing is a common electrode. A layer of piezoelectric film is separated a distance from the common electrode by a suspension medium. The suspension medium contains electrially charged pigmented particles, the color of which contrasts with the color of the suspension medium. The housing has an opening for applying localized pressure to one surface of the piezoelectric film. In addition, the apparatus has a source for energizing the common electrode to a preselected electric potential. By applying a force or infrared energy to an area of the piezoelectric film a charge accumules on the inner surface of the film, directly under the point of application of the force. This charge attracts the electrically charged pigmented particles in the suspension medium which are visible through the film and create an image display.