See-through digitizer with clear conductive grid

• US 5,381,160 A
• Filed: 10/30/1991
• Issued: 01/10/1995
• Est. Priority Date: 09/27/1991
• Status: Expired due to Term

• Current Assignee: Einstruction Gtco Holdings, LLC
• Original Assignee: CalComp, Inc. (Martin Marietta Corporation)
• Inventors: Landmeier, Waldo L.
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): GOON, GIN F
• Application Number:
  US07/784,929
• Time in Patent Office: 1,168 Days
• Field of Search: 340/712, 340/784 I, 340/707, 340/706, 178/18, 178/19, 345/87, 345/100, 345/102, 345/104, 345/173-183
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A combined display and electromagnetic digitizing input device for pen-driven computers. There is a graphics display panel having a viewing surface and a back surface. A first grid of parallel transparent conductors for connection to electromagnetic digitizing electronics to sense the location of an electromagnetic stylus is disposed over one of the surfaces. A second grid of parallel transparent conductors for connection to the electromagnetic digitizing electronics is disposed over the first grid of parallel transparent conductors electrically insulated therefrom and perpendicular thereto. The two grids are constructed of flexible transparent substrates carrying a plurality of transparent indium tin oxide conductors thereon. For improved performance, shielding is provided in the form of a sheet of a transparent conductive material connected to ground potential disposed below the grids of conductors as well as a sheet of a metal foil disposed across the extents of the grids of conductors. Viewing of the display panel or backlighting of the display panel can take place through the grids depending on the display panel employed.

Claims

1. A combined display and cordless electromagnetic digitizing input device for a computer comprising:

a) a graphics display panel having a viewing surface and a non-viewing back surface;

b) a cordless electromagnetic digitizing input device comprising,

b1) a first grid of parallel transparent conductors including means for connection to electromagnetic digitizing electronics to sense the location of an electromagnetic stylus in a first axis of a coordinate system associated therewith disposed over said back surface, said first grid of parallel transparent conductors comprising a first flexible transparent substrate carrying a plurality of first transparent indium tin oxide conductors thereon, and

b2) a second grid of parallel transparent conductors including means for connection to said electromagnetic digitizing electronics to sense the location of said electromagnetic stylus in a second axis of said coordinate system associated therewith disposed over said first grid of parallel transparent conductors electrically insulated therefrom and perpendicular thereto, said second grid of parallel transparent conductors comprising a second flexible transparent substrate carrying a plurality of second transparent indium tin oxide conductors thereon;

c) a backlighting panel disposed adjacent said electromagnetic digitizing input device for backlighting said graphics display panel through said electromagnetic digitizing input device; and

,

d) a sheet of a transparent conductive material connected to ground potential disposed between said electromagnetic digitizing input device and said backlighting panel for shielding the electrostatic interference.

2. The combined display and cordless electromagnetic digitizing input device for a computer of claim 1 and additionally comprising:

a sheet of a metal foil disposed under said display panel and said electromagnetic digitizing input device across the extents of said first grid of parallel transparent conductors and said second grid of parallel transparent conductors and said backlighting panel.

3. In a combined display and cordless electromagnetic digitizing input device for a computer having a graphics display panel with a viewing surface and a back surface opposite the viewing surface, and a backlighting panel disposed adjacent said digitizing input device for backlighting said graphics display panel through said digitizing input device, a transparent grid wire assembly for electromagnetic positional determination of a stylus in a coordinate system associated with the display panel comprising:

a) a first grid of parallel transparent conductors including means for connection to electromagnetic digitizing electronics to sense the location of the stylus in a first axis of the coordinate system disposed over the back surface, said first grid of parallel transparent conductors comprising a first flexible transparent substrate carrying a plurality of first transparent indium tin oxide conductors thereon;

b) a second grid of parallel transparent conductors including means for connection to said electromagnetic digitizing electronics to sense the location of the stylus in a second axis of the coordinate system disposed over said first grid of parallel transparent conductors electrically insulated therefrom and perpendicular thereto, said second grid of parallel transparent conductors comprising a second flexible transparent substrate carrying a plurality of second transparent indium tin oxide conductors thereon; and

,

c) a sheet of a transparent conductive material connected to ground potential disposed over said second grid of parallel transparent conductors and adjacent to the backlighting panel for shielding the electrostatic interference.

4. The transparent grid wire assembly of claim 3 additionally comprising:

a sheet of a metal foil disposed behind the backlighting panel across the extents of said first grid of parallel transparent conductors and said second grid of parallel transparent conductors.

5. In a combined display and cordless electromagnetic digitizing input device for a computer having a graphics display panel with a viewing surface and a back surface opposite the viewing surface, a transparent grid wire assembly to be positioned over the back surface for subsequent electromagnetic positional determination of a stylus in a coordinate system associated with the display panel comprising:

a) a first flexible transparent substrate disposed over the back surface, carrying a plurality of first transparent indium tin oxide conductors thereon comprising a first grid of parallel transparent conductors, and including means for connection to electromagnetic digitizing electronics to sense the location of the stylus in a first axis of the coordinate system;

b) a second flexible transparent substrate adhesively attached to said first flexible transparent substrate, carrying a plurality of second transparent indium tin oxide conductors thereon comprising a second grid of parallel transparent conductors perpendicular to said first grid of parallel transparent conductors, and including means for connection to said electromagnetic digitizing electronics to sense the location of the stylus in a second axis of the coordinate system; and

,

c) a sheet of a transparent conductive material connected to ground potential disposed over said second grid of parallel transparent conductors for shielding the electrostatic interference whereby backlighting of the graphics display panel by a backlighting panel takes place through said sheet of a transparent conductive material, said first flexible transparent substrate, and said second flexible transparent substrate.

6. The transparent grid wire assembly of claim 5 and additionally comprising:

a sheet of a metal foil disposed behind said backlighting panel across the extents of said first grid of parallel transparent conductors and said second grid of parallel transparent conductors.