Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
2001-04-12
2002-06-04
Vu, David H. (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C315S169100, C345S060000, C345S055000, C345S067000, C345S076000, C345S074100
Reexamination Certificate
active
06400094
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for driving an AC (alternating current) type plasma display panel and more particularly to the method for driving the AC-type plasma display panel which is effective in driving a scanning/sustaining separation three-electrode AC-type plasma display panel.
The present application claims priority of Japanese Patent Application No.2000-110936 filed on Apr. 12, 2000, which is hereby incorporated by reference.
2. Description of the Related Art
Generally, a plasma display panel (hereinafter, referred to as a PDP) incorporates many features in that it can be made thin, it can comparatively easily display a large screen, it can provide a wide-range viewing angle, it can provide a high response speed or a like. Therefore, in recent years, it is used for a wall-mounted television, public display plate or a like in a form of a flat display device. The PDP can be classified, by operation mode, into two groups; one being a DC (direct current)-type PDP adapted to be operated with its electrode being exposed to discharge space (that is, to discharge gas) and in a direct current discharging condition and another being an AC-type PDP adapted to be operated with its electrode coated with dielectric layers and without its electrode being directly exposed to discharging gas and in an alternating current discharging condition. In the DC-type PDP, discharge occurs while a voltage is being applied. In the AC-type PDP, discharge is sustained by changing a polarity of a voltage to be applied. Moreover, in the AC-type PDP, e number of electrodes contained in one cell is two or three.
Configurations and driving method of a conventional three-electrode AC-type PDP are described below.
FIG. 7
is a cross-sectional view of one example of a cell used for a conventional PDP. The conventional three-electrode AC-type PDP includes a front substrate
20
and a rear substrate
21
both of which are placed opposite to each other, a plurality of scanning electrodes
22
each being disposed between the front substrate
20
and the rear substrate
21
, a plurality of common electrodes
23
and a plurality of data electrodes
29
and display cells (described later in
FIG. 8
) each being disposed at each of intersections of each of the scanning electrodes
22
and each of the common electrodes
23
and each of the data electrodes
29
. As the front substrate
20
, a glass substrate or a like is used. Each of the scanning electrodes
22
and each of the common electrodes
23
are placed at a specified interval. On these scanning electrodes
22
and common electrodes
23
is formed a transparent dielectric layer
24
. On the transparent dielectric layer
24
is formed a protecting layer
25
made up of MgO (Magnesium oxide) or a like adapted to protect the transparent dielectric layer
24
from discharging. On the other hand, as the rear substrate
21
, a glass substrate or a like is used. Each of the data electrodes
29
is so mounted as to be orthogonal to each of the scanning electrodes
22
and to each of the common electrodes
23
. On the data electrodes
29
is formed a white dielectric layer
28
. On the white dielectric layer
28
is formed a phosphor layer
27
. Between front substrate
20
and rear substrate
21
is placed a partition wall (not shown) at a specified interval in parallel to a face of paper in which
FIG. 7
is shown. The partition wall is used to secure discharge space
26
and to demarcate pixels. The discharge space
26
is filled, in a sealed manner, with mixed gas such as He (Helium), Ne (Neon), Xe (Xenon) or a like, as discharge gas to be used for discharge. The conventional three-electrode AC-type PDP having such configurations as described above is disclosed in SID (Society for Information Display) 98 DIGEST (P279-281, May, 1998).
FIG. 8
is a plan view of the conventional three-electrode AC-type PDP. As shown in
FIG. 8
, at each of intersections of each electrode Si (i=1 to m) making up the scanning electrodes
22
and each electrode Ci (i=1 to m) making up the common electrode
23
and each electrode Dj (1 to n) making up the data electrode
29
, each of display cells
31
is disposed. These display cells
31
are placed in a matrix form.
Next, a conventional method for driving a PDP will be described below. As the method for driving the PDP, a scanning/substaining separation method (ADS method) in which a scanning period and a sustaining period are separated is in the present mainstream. However, this method requires a plurality of sub-fields (SF) for displaying a gray shade and also requires the scanning period for each of the SFs. Therefore, if the number of gray scales or the number of scanning lines is increased, the scanning period forms an increasing proportion of one field and, as a result, the sustaining period forms a decreasing proportion of the one field, causing low luminance in display. To solve this problem, an alternative method for driving the PDP by which the gray shade can be displayed by one time scanning without using such SFs is proposed. The method of this type for driving the PDP is disclosed, for example, in Japanese Patent Application Laid-open No. Hei 9-81073.
The scanning/sustaining separation method will be described.
FIG. 6
is a diagram showing waveforms explaining driving operations of the conventional three-electrode AC-type PDP. One field
1
is made up of three periods including a preliminary discharge period
2
, a scanning period
3
and a sustaining period
4
.
First, the preliminary discharge period
2
will be described. A preliminary discharge pulse
5
with positive polarity is applied to the common electrode
23
and a preliminary discharge pulse
6
with negative polarity is applied to the scanning electrode
22
. This enables resetting of irregularity caused by light emitting conditions in a pre-field period, in a state in which wall charges occur at a final stage of a pre-SF and enables initialization and, at a same time, this causes all pixels to be forcedly discharged, thus providing a priming effect which induces subsequent writing discharge to occur at a lower voltage. Since this preliminary discharge pulse
5
causes all pixels to be discharged, a voltage of the preliminary discharge pulse
5
has to be higher than those of a scanning pulse and sustaining pulse.
Moreover, though, in the example shown in
FIG. 6
, both the preliminary discharge pulses
5
and
6
are applied once with same timing, in some cases, two kinds of pulses each having a different role are applied, that is, a priming pulse to cause all pixels to be discharged and priming effects to be implemented is applied after a sustainment extinguishing pulse to cause the state of the pre-field to be reset has been applied. At this point, in some cases, a different sustainment extinguishing pulse is applied not only once but also two or more numbers of times.
Furthermore, though, in the example shown in
FIG. 6
, to extinguish the wall charge produced by the preliminary discharge, a self-extinguishing process by using a fall of each of the preliminary discharge pulses
5
and
6
is employed, in some cases, a preliminary discharge extinguishing pulse is applied to extinguish these wall charges separately. In some cases, the preliminary discharge extinguishing pulse is also applied not only once but also two or more numbers of times.
Moreover, in some cases, these pulses are applied to other electrodes. In any case, the wall charge on the dielectric layer produced by the preliminary discharge is extinguished or is controlled to be proper in quantity.
Next, the scanning period
3
is described below. During the scanning period
3
, the scanning pulse
8
is applied sequentially to each of electrodes (S
1
to Sm) making up the scanning electrode
22
. At the same time when the scanning pulse
8
is applied, a data pulse
9
is applied, in a manner so as to correspond to a display pattern, to each of electrodes (D
1
to Dm) making up the data electrode
29
. The data
NEC Corporation
Vo Tuyet T.
Vu David H.
Young & Thompson
LandOfFree
Method for driving AC-type plasma display panel 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 for driving AC-type plasma display panel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for driving AC-type plasma display panel will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2959322