Electromagnetic digitizer and distortion-free LCD

• US 20030025677A1
• Filed: 07/19/2002
• Published: 02/06/2003
• Est. Priority Date: 07/24/2001
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Yamamoto, Sadao, Namura, Takashi, Chikami, Toshihide, Iwamoto, Naohisa
• Granted Patent: US 6,906,694 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

An input/output device is disclosed that includes a digitizer with an LCD mounted thereon and a protective layer mounted directly on the LCD to minimize the parallax errors that have heretofore occurred when a protective layer was mounted in a spaced relation from an LCD. The LCD is a fringe field switching (FFS) LCD which does not distort when pressure is applied to its upper surface through the directly connected protective layer.

Claims

1. A device comprising:

an FFS LCD including a top panel having a writing surface;

a stylus; and

a position detector operably connected to said LCD for detecting a position of said stylus on said writing surface and creating an image on said LCD at a location corresponding to said position.

2. The device of claim 1 wherein said position detector comprises a digitizer.

3. The device of claim 2 wherein said digitizer comprises an electromagnetic digitizer.

4. The device of claim 1 wherein said top panel comprises a layer of acrylic.

5. The device of claim 1 wherein said top panel comprises a layer of polycarbonate.

6. The device of claim 1 wherein said LCD includes a polarizer having a top face, said top panel comprises a sheet of material having a bottom face, and said polarizer top face is in face-to-face engagement with said top panel bottom face.

7. A device comprising:

an FFSLCD;

a flexible sheet of material having a bottom face and a top face comprising a writing surface mounted over said LCD and spaced therefrom by a first distance, said sheet of material having a deflection distance greater than said first distance; and

a position detector operably connected to said LCD for detecting a position of a stylus on said writing surface and creating an image on said LCD at a location corresponding to said position.

8. A method of manufacturing a device comprising the steps of:

providing an FFS LCD having a top surface;

attaching a protective layer of material having a writing surface directly to said LCD top surface;

operably connecting a position detector to said LCD for detecting a position of a stylus on said writing surface and creating an image on said LCD corresponding to said position.

9. An input/output device comprising:

a digitizer;

an FFS LCD having a first side connected to said digitizer and a second side; and

a protective layer of material comprising a writing surface mounted directly to said LCD second side.

10. The input output device of claim 9 wherein said protective layer comprises a layer of acrylic.

11. The input output device of claim 9 wherein said protective layer comprises a layer of polycarbonate.

12. The input/output device of claim 9 wherein said LCD second side comprises a polarizer having a top face and wherein said protective layer of material comprises a top surface comprising said writing surface and a bottom surface, said bottom surface being in face-to-face engagement with said polarizer top face.

13. The input/output device of claim 9 wherein said digitizer comprises an electromagnetic digitizer.

14. The input/output device of claim 9 wherein said protective layer is removably attached to said LCD second side.

15. An input/output device comprising:

a digitizer; and

an FFS LCD mounted on said digitizer and having a top layer, wherein said top layer comprises a writing surface for a digitizer stylus.

16. The input/output device of claim 15 wherein said LCD includes, a polarization filter and wherein said top layer comprises said polarization filter.

17. The input/output device of claim 15 wherein said digitizer comprises an electromagnetic digitizer.

18. An input/output device comprising:

an electromagnetic digitizer;

an FFS LCD mounted on said digitizer; and

a protective layer of material, selected from the group consisting of acrylic and polycarbonate, forming a writing surface removably mounted over said LCD and spaced therefrom by a gap having a width;

wherein said protective layer is resiliently deflectable by a deflection distance greater than the width of said gap when pressure is applied to said protective layer.

19. A method of manufacturing an input/output device comprising the steps of:

providing a digitizer;

mounting an FFS LCD on said digitizer;

attaching a protective layer of material directly to said LCD;

connecting said digitizer to said LCD such that a stylus having a tip moving across said protective layer will be detected by said digitizer and such that an image will be formed on said LCD beneath said stylus tip.

20. The input/output device of claim 19 wherein the step of providing a digitizer comprises the step of providing an electromagnetic digitizer.