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High Resolution CRT Display Overlay for Probe Position Determination

IP.com Disclosure Number: IPCOM000038914D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Dickerson, JA: AUTHOR [+2]

Abstract

An improved CRT overlay is described which makes use of the piezoelectric effect produced when a stress (force) is applied to polyvinylidene fluoride film in a direction perpendicular to the film. A stylus (i.e., ballpoint pen) or finger will serve as the source of stress. Other applications exist, for example, in robotics for tactile sensing (Image Omitted) and flat surface object recognition. Typical piezoelectric film (e.g., type "KF" from Kureha Corp.) is fabricated with top and bottom surface lines of metallized aluminum. For the CRT display overlay application, metallized indium-tin oxide is used because it is a transparent conductor. Fig. 1 illustrates in simplistic form a layout for touch panel 1 carried on an electronic circuit board 2 which carries appropriate scan logic (Fig. 2).

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High Resolution CRT Display Overlay for Probe Position Determination

An improved CRT overlay is described which makes use of the piezoelectric effect produced when a stress (force) is applied to polyvinylidene fluoride film in a direction perpendicular to the film. A stylus (i.e., ballpoint pen) or finger will serve as the source of stress. Other applications exist, for example, in robotics for tactile sensing

(Image Omitted)

and flat surface object recognition. Typical piezoelectric film (e.g., type "KF" from Kureha Corp.) is fabricated with top and bottom surface lines of metallized aluminum. For the CRT display overlay application, metallized indium-tin oxide is used because it is a transparent conductor. Fig. 1 illustrates in simplistic form a layout for touch panel 1 carried on an electronic circuit board 2 which carries appropriate scan logic (Fig. 2). Artwork for top and bottom surfaces of the film is illustrated at 3 and 4. The artwork shown is enlarged for illustration only. Thin film photolithography is used to etch the top and bottom artwork pattern. Line widths of 0.010" and spaces of 0.0065" are suitable. The two sets of lines at 3 and 4 have an X-Y orientation. This configuration (preferably 320 lines x 320 lines) yields a total of 102,400 intersections. Each intersection contains an isolated piezoelectric cell, such as 6 (Fig. 2). Each cell is a switchable (when stress is applied) voltage source. For very light pressures applied with a ballpoint pe...