Handwritten character input device

• US 4,723,836 A
• Filed: 10/10/1984
• Issued: 02/09/1988
• Est. Priority Date: 10/26/1983
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kono, Yoshio, Inoue, Yukihiro
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Lewis, David
• Application Number:
  US06/659,419
• Time in Patent Office: 1,217 Days
• Field of Search: 340/707, 340/708, 340/784, 350/331 R, 350/338, 350/332-334
• US Class Current: 349/12
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A handwritten character input device includes an opaque tablet or digitizer for inputting a handwritten character or figure into an apparatus. The tablet is of an electromagnetic induction type. The tablet is positioned under a liquid crystal display panel and an aluminum-evaporated film reflector is provided for the liquid crystal display. Preferably, the aluminum-evaporated film reflector is as thick as 1.0 micron or less. A conductive shield plate may be further provided between the tablet and a driving circuit substrate for the liquid crystal display panel. This shield plate serves to magnetically isolate the tablet from the driving substrate.

Claims

1. A handwritten character input device comprising:

exciting means for exciting and inputting character information by hand-writing a character;

electromagnetic induction tablet means, responsive to said exciting means, for sensing the character inputted by said exciting means, said electromagnetic induction tablet being opaque;

liquid crystal display panel means, responsive to the detection of said electromagnetic induction tablet means, for displaying the inputted character; and

an aluminum-evaporated film reflector serving to reflect radiation toward said liquid crystal display panel means, said aluminum-evaporated film reflector being disposed between said liquid cyrstal display panel and said electromagnetic induction tablet means and having a thickness of 1.0 micron or less;

wherein said exciting means comes in contact with a first top side of said liquid crystal display means with said electromagnetic induction tablet means being positioned beneath a second, bottom side of said liquid crystal display means.

2. The device of claim 1, further comprising:

a substrate carrying driving circuitry that drives said liquid crystal display panel means; and

a conductive shield plate positioned between said electromagnetic induction table means and said substrate.

3. The device of claim 1 wherein said liquid crystal display panel means comprises:

a first polarizer, forming said first top side of said liquid crystal display panel means;

a first glass substrate and a second glass substrate disposed beneath said first polarizer, and sealing a liquid crystal layer; and

a second polarizer, disposed beneath said first and second glass substrates, forming said second bottom side of said liquid crystal display panel means.

4. The device of claim 3 wherein said first polarizer has a thickness of approximately 200 microns, said first and second substrates each have a thickness of approximately 0.7 millimeters and said second polarizer and said aluminum evaporated film reflector have a combined thickness of approximately 230 microns.

5. The device of claim 3 further comprising:

driving means for activating said liquid crystal display means, said driving means being disposed on a third substrate, said third substrate being positioned such that said electromagnetic induction table means is between said liquid crystal display panel means and said third substrate; and

a conductive shield plate disposed between said third substrate and said electromagnetic induction tablet means.