Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2001-10-30
2004-05-25
Wu, Xiao (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S211000
Reexamination Certificate
active
06741226
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for driving a plasma display and to a plasma display and more particularly to the method for driving the plasma display which is capable of avoiding an increase in costs for manufacturing the plasma display by omitting use of a costly forced-discharging circuit which is made possible by detecting, while power is off, a drop in a voltage fed from a main high-voltage power source and by changing a method of driving an X driver to cause an electric charge being left in an auxiliary high-voltage power source to be discharged, and to the plasma display.
The present application claims priority of Japanese Patent Application No. 2000-331184 filed on Oct. 30, 2000, which is hereby incorporated by reference.
2. Description of the Related Art
FIG. 4
is a diagram of a functional block explaining a conventional plasma display. In
FIG. 4
, there are provided an X driver
14
, a signal control circuit
16
, a voltage detecting circuit
17
, a forced discharging circuit
18
, contacts
21
,
22
,
23
, and
24
, lines for transmitting signals
31
,
32
, and
33
, capacitors C
1
and C
2
, a diode D
1
, ground potential terminals GND, a MOSFET M
3
(Metal Oxide Semiconductor Field Effect Transistor), resistors R
1
, R
2
, and R
3
, an auxiliary high-voltage power source Vp and a main high-voltage power source Vs.
In the conventional plasma display as shown in
FIG. 4
, when any preventive measure against sequences in which power from a low-voltage power source Vcc (not shown), the main high-voltage power source Vs, and the auxiliary high-voltage power source Vp is turned OFF is not taken while the power is OFF, if the power from the low voltage power source Vcc (not shown) is turned OFF before the power from the main high-voltage power source Vs and auxiliary high-voltage power source Vp is turned OFF, a gate potential of a MOSFET (for example, a MOSFET M
1
and a MOSFET M
2
making up the X driver
14
) being used in a high-voltage system reaches a level of floating, which causes a feed through current to flow in the MOSFET M
1
and the MOSFET M
2
due to noises or a like and also causes the MOSFET M
1
and the MOSFET M
2
to be damaged, in some cases. Conventionally, in order to protect circuits in a high-voltage system, a forced discharging circuit is provided to the main high-voltage power source Vs and the auxiliary high-voltage power source Vp and the power from the main high-voltage power source Vs and from the auxiliary high-voltage power source Vp is turned OFF before the power from the low-voltage power source Vcc (not shown) is turned OFF.
In the conventional method, as described above, to protect circuits in the high-voltage system, the forced discharging circuit
18
made up of the MOSFET M
3
and the resistor R
3
is provided. A drain of the MOSFET M
3
is connected to the auxiliary high-voltage power source Vp, its gate is connected to the line for transmitting signals
33
and the resistor R
3
is connected between the contact
24
and the ground potential terminal GND.
Moreover, a drain of the MOSFET M
1
is connected through the contact
21
and the diode D
1
to the auxiliary high-voltage power source Vp and the capacitor C
1
, its gate is connected to the signal control circuit
16
line for transmitting signals
31
and its source is connected to a drain of the MOSFET M
2
.
The drain of the MOSFET M
2
is connected through the contact
22
to the source of MOSFET Ml and the capacitor C
2
and its gate is connected to the line for transmitting signals
32
, and its source is connected to the ground potential terminal GND.
The voltage detecting circuit
17
is mounted so as to detect a voltage at the contact
23
disposed between the resistor R
1
connected to the main-high voltage power source Vs and the resistor R
2
connected to the ground potential terminal GND.
FIG. 5
is a timing chart explaining operations of the conventional plasma display of FIG.
4
. In
FIG. 5
, “T
1
” indicates a first time, “T
2
” indicates a second time, “T
5
” indicates a fifth time and “T
6
” indicates a sixth time.
Referring to
FIG. 5
, in the conventional plasma display, when the power is turned OFF at the first time T
1
, a voltage fed from the main high-voltage power source Vs (see
FIG. 4
) begins to drop and, when a voltage at the contact
23
reaches a predetermined voltage set by the voltage detecting circuit
17
at the second time T
2
, the voltage detecting circuit
17
operates to output to the line for transmitting signals
33
. When the signal
33
goes high, the forced discharging circuit
18
operates and the voltage fed from the auxiliary high-voltage power source Vp becomes 0 (zero) at the fifth time T
5
. Then, after a lapse of the time set at a time when the power is turned OFF, at the sixth time T
6
(T
6
>T
5
), the voltage fed from the low-voltage power source Vcc (not shown) is lowered to 0 (zero) volts.
However, in the conventional method, since the forced discharging circuit
18
is introduced and the power from the main high-voltage power source Vs and the auxiliary high-voltage power source Vp is turned OFF before the power from the low-voltage power source Vcc (not shown) is turned OFF, though the damage in the MOSFET M
1
and the MOSFET M
2
can be avoided, introduction of an expensive forced discharging circuit causes manufacture of a PDP (Plasma Display Panel) to be costly.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the present invention to provide a method for driving a plasma display which is capable of avoiding an increase in costs for manufacturing the plasma display by detecting a drop in a voltage fed from a main high-voltage while power is OFF and by changing a method for driving an X driver to cause an electric charge being residual in an auxiliary high-voltage power source to be discharged, thereby enabling an omission of use of a costly forced discharging circuit, and to provide the above plasma display.
According to a first aspect of the present invention, there is provided a method for driving a plasma display including a power source used to produce power from a low-voltage power source and a main high-voltage power source and a display section having a plasma display panel, an X driver and a Y driver each being used to drive the plasma display panel, a signal control circuit, a voltage detecting circuit used to detect a voltage fed from the main high-voltage power source and an auxiliary high-voltage power source, the method including:
a step of detecting a state of power-off by using the voltage detecting circuit used to detect a voltage fed from the main high-voltage power source while power is off and operating the X driver or the Y driver used to drive the plasma display panel to discharge electrical charges being left in the auxiliary high-voltage power source.
In the foregoing, a preferable mode is one that wherein includes a step of detecting a drop in a voltage fed from the main high-voltage power source while power is off and changing a method of driving the X driver to discharge the electrical charges being left in the auxiliary high-voltage power source.
Also, a preferable mode is one that wherein includes a step of detecting a drop in a voltage fed from the main high-voltage power source while power is off and changing a method of driving the Y driver to discharge the electrical charges being left in the auxiliary high-voltage power source.
Also, a preferable mode is one that wherein includes:
a step of stopping a supply of power fed from the main high-voltage power source and the auxiliary high-voltage power source when power is turned off at a first time and maintaining a voltage by using electrical charges being left in a capacitor for smoothing mounted in the main high-voltage power source and the auxiliary high-voltage power source;
a step of causing the voltage detecting circuit to operate to output a first signal when a voltage fed from the main high-voltage power source drops and a voltage at a first c
NEC Corporation
Wu Xiao
Young & Thompson
LandOfFree
Method of driving plasma display and plasma display does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of driving plasma display and plasma display, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of driving plasma display and plasma display will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3265831