Computer graphics processing and selective visual display system – Display peripheral interface input device – Touch panel
Reexamination Certificate
2001-02-08
2003-09-30
Nguyen, Chanh (Department: 2675)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Touch panel
C178S018050
Reexamination Certificate
active
06628269
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a touch panel input device, and in particular, to a touch panel input device which is disposed in a display section including a liquid-crystal device (LCD) and in which a coordinate signal is sensed using a change in a position depressed by a finger (fingertip), a pen or the same in association with a content displayed on the display section and the coordinate signal thus sensed is inputted to a device connected to the touch panel input device.
DESCRIPTION OF THE PRIOR ART
A touch panel input devices of prior art include a touch panel of transparent resistive film type.
FIG. 1
shows in a cross-sectional view a configuration of the touch panel using transparent resistive films
500
of the prior art.
The touch panel
500
shown in
FIG. 1
includes a transparent film
51
, a first transparent resist film
52
, a second transparent resistive film
53
, a glass substrate
54
, and a dot spacers
55
disposed over an upper surface of the second transparent resistive film
53
with a fixed gap therebetween.
The transparent film
51
includes a flexible transparent film member constituting a surface section of the touch panel
500
. The film
51
includes, for example, a transparent plastic film such as polyethylene terephthalate (PET). The film
51
has a flexibility enough to easily bend or to easily change its form when depressed by a finger or a pen.
The first transparent resistive film
52
includes a transparent conductive film made of, for example, indium tin oxide (ITO) or SnO
2
. The film
52
is arranged entirely on a lower surface of the transparent film
51
and has nearly a uniform thickness. When the film
51
is pushed by a finger, the film
52
is distorted together with the film
51
.
The second transparent resistive film
53
includes, like the first transparent resistive film
52
, a transparent conductive film made of the above-mentioned same materials. The film
53
is arranged throughout on an upper surface of the glass substrate
54
, which will be described later, and has nearly a uniform thickness.
The glass substrate
54
forms a bottom section of the touch panel. The film
53
having a uniform thickness is disposed entirely on an upper surface of the glass substrate
54
.
The dot spacers
55
prevent the first transparent resistive film
52
on the transparent film
51
from being brought into contact with the second transparent resistive film
53
arranged on the glass substrate
54
in an no-input state of the panel
500
. Additionally, density of dot spacers
55
determines magnitude of pressure required to bring the transparent resistive film
52
into contact with the transparent resistive film
53
.
FIG. 2
shows in a cross-sectional view a state of the touch panel
500
using transparent resistive films of the prior art in which the panel is depressed by a touch panel pen or a fingertip of a user.
When the user pushes, by his or her finger or a pen, the transparent film
51
on the upper surface side of the touch panel
500
, the films
51
an
52
are rendered to a distorted state as shown in FIG.
2
.
The film
51
on the upper surface side of the touch panel
500
is bent by pressure of the pen or a fingertip, and the first transparent resistive film
52
makes contact with the second transparent resistive film
53
. The films
52
and
53
are set to an electrically conductive state. By sensing the conductive state, the panel
500
detects an event of depression on the film
51
.
FIG. 3
shows constitution of a sensor circuit to sense an input coordinate position in a touch panel using transparent resistive films of the prior art. The position sensor senses a pair of coordinates (input coordinates) of a contact point between the films
52
and
53
.
The input coordinate sensor of the touch panel shown in
FIG. 3
includes a first transparent resistive film
601
, a second transparent resistive film
602
, a first resistor
603
schematically shown on the first film
601
, a second resistor
604
schematically shown on the second film
602
, analog switches
605
to
608
, and analog-to-digital (A/D) converters
609
and
610
.
Although each of the resistors
603
and
604
includes one resistor having an ordinary contour in
FIG. 3
, the resistor actually has a planar shape, namely, a transparent resistive film like the first and second transparent resistive films
601
.
The first resistor
603
(first transparent resistive film
601
) has two electrodes respectively connected to the analog switches
605
and
606
. The switches
605
and
606
are coupled with a power source voltage V and ground, respectively.
The second resistor
604
(second transparent resistive film
602
) includes two electrodes linked with the analog switches
607
and
608
, respectively. Connected to the switches
607
and
608
are a power source voltage V and ground, respectively.
In
FIG. 3
, the first and second transparent resistive films
601
and
602
are fixed or laminated onto each other such that the electrodes
605
and
606
of the film
601
are vertical to the electrodes
607
and
608
of the film
602
. The first and second electrodes
603
and
604
are respectively coupled with the A/D converters
609
and
610
.
Referring to the input coordinate sensing circuit shown in
FIG. 3
, description will a given of operation to sense a contact point, namely, a pair of coordinates associated with actual depression on the touch panel. Assume tat the transparent film
51
of the touch panel
500
is depressed at a position by a fingertip or a pen of the user, for example, as shown in FIG.
2
and the upper
52
and lower films
53
are brought into contact with each other at the depressed position.
FIG. 4
shows a first configuration of a state of the input coordinate sensor in which the touch panel is in the state of FIG.
2
. When the user pushes a particular point on the touch panel in the situation of
FIG. 4
, the sensor conducts control operation to drive switches thereof to enter a subsequent state.
As a result of the control operation of the switches, a linear potential distribution is formed on the first resistor
603
ranging from a voltage V (volt) to 0 (volt) in a direction as indicated by an arrow mark a as shown in FIG.
4
.
In
FIG. 4
, an arrow mark b designates a point (to be referred to as a “contact point” herebelow) at which the first and second transparent resistive films
601
and
602
come in contact with each other. By reading a value indicated by the A/D converter
609
in this state, an electric potential at the contact point indicated by the arrow mark b on the second resistor
604
can be detected. Since the potential is linearly distributed on the second resistor
604
ranging from a voltage V (volt) to 0 (volt), the obtained potential tells distance of the point from the electrode c in the direction of the arrow mark a. When the direction is aligned to that of an x axis of the coordinate system, the obtained value represents an x coordinate value.
FIG. 5
shows a second construction of a state of the input coordinate sensor associated with the state of the touch panel in FIG.
2
. In response to depression at a particular point on the touch panel in the state shown in
FIG. 4
, the sensor controls its switches to enter a next state.
As shown in
FIG. 5
, the control operation of the switches causes a linear potential to ve linearly distributed on the first resistor
603
ranging from a voltage V(volt) to 0(volt) in a direction as designate by an arrow mark d.
In
FIG. 5
, an arrow mark b indicates a point (a contact point) between the first and second transparent resistive films
601
and
602
. By sensing a value resultant from the A/D converter
610
in this situation, potential at the contact point indicated by the arrow mark b on the first resistor
603
can be detected. Also distributed on the first resistor
603
is a linear potential ranging from a voltage V (volt) to 0 (volt), the potential represents distance of the point from the electrode e in the direction
NEC Corporation
Nguyen Chanh
Whitham Curtis & Christofferson, P.C.
LandOfFree
Touch panel input device capable of sensing input operation... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Touch panel input device capable of sensing input operation..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Touch panel input device capable of sensing input operation... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3048565