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Browse Prior Art Database

Three-Point Touch Control System

IP.com Disclosure Number: IPCOM000039268D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Callaway, MB: AUTHOR [+3]

Abstract

A touch panel spaced from a CRT display is mounted by three spaced piezoelectric transducers each including a preload force compressing the transducers before the panel is touched. Fig. 1 is a partial cross-sectional view of a display and touch screen mounted by piezoelectric transducers. Fig. 2 is a front view of the screen and CRT. As shown in the figures, a display 1, which is preferably a cathode ray tube (CRT), has a touch screen 2 mounted at a spaced location from the face of the display, supported at three points by piezoelectric transducers 3, 4, 5. The transducers 3, 4, 5 are arranged to form an isosceles triangle. The touch screen 2 is, in its preferred embodiment, a flexible screen which is carried on a frame (Image Omitted) member 6 which is in engagement with the piezoelectric transducer 3.

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Three-Point Touch Control System

A touch panel spaced from a CRT display is mounted by three spaced piezoelectric transducers each including a preload force compressing the transducers before the panel is touched. Fig. 1 is a partial cross-sectional view of a display and touch screen mounted by piezoelectric transducers. Fig. 2 is a front view of the screen and CRT. As shown in the figures, a display 1, which is preferably a cathode ray tube (CRT), has a touch screen 2 mounted at a spaced location from the face of the display, supported at three points by piezoelectric transducers 3, 4, 5. The transducers 3, 4, 5 are arranged to form an isosceles triangle. The touch screen 2 is, in its preferred embodiment, a flexible screen which is carried on a frame

(Image Omitted)

member 6 which is in engagement with the piezoelectric transducer 3. The frame member 6 is also urged into contact with the transducer by a spring 7 which provides a preload force or a negative normal force on the frame 6 and the transducer 3 before the panel is touched. This preload allowed a touch outside of the triangle formed by connecting the three piezoelectric transducers 3, 4, 5 to be effectively sensed by a reduction in the preload or at least one transducer and its position to be recorded. U. S. Patent 4,355,202 and IBM Technical Disclosure Bulletin 29, 3171-3172 (December 1986) provide further details of the touch panel technology.

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