Position detecting device and display device

Patent metadata

Field	Value
Publication number	US-9001084-B2
Application number	US-96090707-A
Country	US
Kind code	B2
Filing date	Dec 20, 2007
Priority date	Dec 25, 2006
Publication date	Apr 7, 2015
Grant date	Apr 7, 2015

Abstract

A position detecting device usable with a display having a display-surface side and a rear-surface side opposite to the front side is provided. The position detecting device includes a position indicator, a detector, and a driving coil. The detector is provided on the display-surface side of the display and is configured to detect signals transmitted from the position indicator. The driving coil is provided on the rear-surface side of the display and is configured to supply electric current to the position indicator.

First claim

What is claimed is:

1. A position detecting device usable with a display having a front side and a rear side opposite to the front side, said position detecting device comprising:
a position indicator for transmitting position-indicating signals;
a position detector for disposing on the front side of the display, said position detector comprising a plurality of first conductive elements that comprise a transparent conductive member for extending across the display to detect said position-indicating signals transmitted from said position indicator, the first conductive elements having a first resistance; and
a driving coil for disposing below the rear side of the display and comprising a second conductive element having a second resistance which is lower than said first resistance of said first conductive element so as to transmit a position-indicator driving signal to said position indicator and thereby induce a current in said position indicator; and
wherein said position indicator comprises a resonant circuit for electromagnetic interaction with said driving coil to induce the current in said position indicator; and
wherein said position detector comprises a plurality of detection coils forming a grid for extending across the display, and wherein said driving coil is operable to transmit a first signal to said position indicator to induce a current in said resonant circuit thereof, and said resonant circuit is operable to transmit a second signal to said detection coils for position detection; and
wherein said driving coil is driven constantly so that said first signal and said second signal are transmitted simultaneously.

2. The position detecting device according to claim 1 , wherein said position detector comprises an electromagnetic induction-type detection coil.

3. The position detecting device according to claim 1 , wherein a current position of said position indicator is detected by comparing received signal strengths of said detection coils.

4. The position detecting device according to claim 1 , wherein said driving coil comprises a plurality of driving coils arrayed across the rear side of the display.

5. The position detecting device according to claim 1 , wherein said driving coil is wound around the rear side of the display repeatedly, said driving coil having a first portion wound around a center of the display and a second portion wound around a periphery of the display.

6. The position detecting device according to claim 1 , wherein said driving coil comprises a first coil wound around a center of the display and a second coil, different from said first coil, wound around a periphery of the display.

7. The position detecting device according to claim 1 , further comprising:
a second driving coil for disposing wound around a periphery of the front side of the display, said driving coil and said second driving coil being driven simultaneously to transmit signals to said position indicator.

8. A position detecting device usable with a display having a front side and a rear side opposite to the front side, said position detecting device comprising:
a position indicator for transmitting position-indicating signals;
a position detector for disposing on the front side of the display, said position detector comprising a plurality of first conductive elements that comprise a transparent conductive member for extending across the display to detect said position-indicating signals transmitted from said position indicator, the first conductive elements having a first resistance; and

a driving coil for disposing below the rear side of the display and comprising a second conductive element having a second resistance which is lower than said first resistance of said first conductive element so as to transmit a position-indicator driving signal to said position indicator and thereby induce a current in said position indicator and;
wherein said driving coil comprises a single driving coil wound spirally along the rear side of the display, said driving coil crossing back and forth along the rear side of the display several times.

9. A display device, comprising:
a display panel having a front display-surface side and a rear-surface side opposite the front display-surface side;
a position detecting device operably associated with said display panel, said position detecting device including
a position indicator for transmitting position-indicating signals; a position detector provided on said front display-surface side of said display panel, said position detector comprising a plurality of first conductive elements that comprise a transparent conductive member extending across the display to detect said position-indicating signals transmitted from said position indicator, the first conducive elements having a first resistance; and
a driving coil provided below said rear-surface side of said display panel and comprising a second conductive element having a second resistance which is lower than said first resistance of said first conductive element so as to transmit a position-indicator driving signal to said position indicator and thereby induce a current in said position indicator; and
wherein said driving coil comprises a single driving coil wound spirally along said rear surface side of said display panel, said driving coil crossing back and forth along said rear surface side several times.

10. The display device according to claim 9 , wherein:
said position detector comprises a plurality of detection coils forming a grid across said front display surface side of said display panel; and
said position indicator comprises a resonant circuit for electromagnetic interaction with said driving coil and said detection coils; and
said driving coil transmits a first signal to said position indicator to induce a current in said resonant circuit, and said resonant circuit transmits a second signal to said detection coils for position detection.

11. The display device according to claim 9 , wherein said driving coil is wound around said rear surface side of said display panel repeatedly, said driving coil having a first portion wound around a center of said display panel and a second portion wound around a periphery of said display panel.

12. The display device according to claim 9 , wherein said driving coil is provided below a center portion and a peripheral portion of said display.

Assignees

• Yamamoto Sadao
• Wacom Co Ltd

Inventors

• Yamamoto Sadao

Classifications

• G06F3/041

  Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means · CPC title

• G06F3/046 Primary

  by electromagnetic means · CPC title