Browse Prior Art Database

Passive Workstation Touch Panel

IP.com Disclosure Number: IPCOM000103610D
Original Publication Date: 1993-Jan-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Williams, DD: AUTHOR

Abstract

Described is a hardware implementation utilizing a passive CCD low-power touch panel. The panel features a CCD array and a reference surface to sense touch points so as to provide high-resolution and high-speed access.

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This is the abbreviated version, containing approximately 75% of the total text.

Passive Workstation Touch Panel

       Described is a hardware implementation utilizing a
passive CCD low-power touch panel.  The panel features a CCD array
and a reference surface to sense touch points so as to provide
high-resolution and high-speed access.

      Fig. 1 shows a diagram of the touch panel components.  Touch
area 10 is positioned between horizontal lens 11 and corresponding
reference surface 12 on the horizontal side and vertical lens 13 and
corresponding reference surface 14 on the vertical side.  Horizontal
lens 11 is focused on horizontal reference surface 12 and horizontal
CCD detector 15.  Vertical lens 13 is also focused on vertical
reference surface 14 and vertical CCD detector 16.

      Fig. 2 shows a diagram of the CCD touch detection elements.
The CCD detector stores an image of the light level reflected from
the reference surface.  The stored image is clocked by means of clock
17 through CCD 15, or 16, one element at a time into level detector
18.  The output of level detector 18 produces signal 19 which
indicates whether the light level at the clocked point is at the
reference level or is different. Signal 19 can then be used to
determine if one or more points are obscured in the touch area.  The
reference surface can be either light or dark, but not grey.  The
touch point is determined by a contrast difference between the touch
object and the reference surface.

      Regarding the touch point resolution, the CCD array...