Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1997-12-23
2002-01-29
Jankus, Almis R. (Department: 2675)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S062000, C345S066000, C345S067000
Reexamination Certificate
active
06342873
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to plasma display devices, and more particularly to a surface discharge type plasma display device having an electrode configuration and a circuitry configuration which are capable of suppressing the occurrence of radiation of electromagnetic field by a plurality of high voltage pulses which form driving waveforms.
2. Prior Art
Plasma display device is one of flat display devices and an emissive type display device. And it has been expected as a display device which may realize a large-scale wall mounting TV because this plasma display may be easily manufactured using thick film technology at relatively low costs. In regard to this plasma display, discharge cells corresponding to display pixels are arranged in a matrix form to selectively discharge a discharge cell for exciting a phosphor with luminous ultraviolet rays, thereby providing three primary colors of red, green and blue. There are a DC type plasma display in which electrodes are exposed in a discharge space and an AC type plasma display in which electrodes are isolated from the discharge space. It is generally known that the AC type plasma display has a longer life time because of the isolation of electrodes from discharge space as stated above. In the AC type plasma display, there are an opposed-electrode type plasma display configured by facing electrodes to each other, and a surface discharge type plasma display having surface discharge electrodes which are configured by arranging electrodes in parallel on one substrate as disclosed in Japanese Unexamined Patent Publication No. 4-332430. Among them, the surface discharge type plasma display is generally considered to be the most suitable for large scale color display because it has a wide memory margin, high brightness and emissive efficiency.
FIG. 4
shows a block diagram of a system configuration of a conventional surface discharge type plasma display device. This display device is similar to the surface discharge type plasma display shown in the article titled “Driving method of 40-inch type full-color ACPDP” in the Japanese monthly magazine “Monthly Display” (pp. 46-50, April, 1996).
According to a block diagram of a drive unit, this conventional surface discharge type plasma display comprises a plasma display panel
15
, a data driver
16
, a sustaining driver
17
, a scanning driver
18
, a scanning pulse generator circuit
19
and a mixer
20
.
Display data and control signal from outside of the device are appropriately converted by an interface circuit, and supplied to a data driver
16
, a sustaining driver
17
and a scanning driver
18
(the interface circuit is not shown in the block diagram).
FIG. 5
shows a schematic cross sectional view as an example of one pixel of a surface discharge type plasma display panel used in the above device. The panel comprises an insulative substrates
1
,
2
, a transparent scanning electrode
3
, a transparent sustaining electrode
4
, trace electrodes
5
,
6
, a data electrode
7
, a dielectric layers
12
,
14
, a protective layer
13
, a phosphor
11
and a plurality of ribs
9
. A numeral
8
designates a discharge gas space. In the figure, though the ribs
9
are not depicted in detail, the striped ribs are formed to be transverse with the scanning electrode
3
and sustaining electrode
4
to separate pixels and keep the space between insulative substrates
1
and
2
. Furthermore, metal electrodes (trace electrodes
6
,
7
) are laminated on both of the scanning electrode
3
and the sustaining electrode
4
to decrease the resistance thereof.
FIG. 6
shows schematic views of driving pulse trains of said surface discharge type plasma display panel. On the scanning electrodes
3
corresponding to the rows of matrix displays, pulse trains SC
1
, SC
2
, SC
3
, SCn (“n” is an integer in response to the number of lines) are applied in the order from the above. Pre-discharge pulses or priming pulses, scanning pulses, sustaining pulses B of the pulse train (SCn) to be applied to the scanning electrode
3
are generated by a high voltage pulse generator
19
for the scanning electrodes
3
, and its timings are controlled by the signal of interface with a scanning driver
18
. The sustaining electrodes
4
paired with scanning electrodes
3
are connected in common and a sustaining pulse trains SUS are applied thereto. The priming pulse and the sustaining pulse A of the pulse train (SUS) to be applied to the sustaining electrodes
4
are generated by a high voltage pulse generator
17
for the sustaining electrodes
4
. Since the priming pulses and the sustaining discharge pulses A, B are applied at the same time to all scanning electrodes
3
and to all sustaining electrodes
4
, it is required that withstand voltage is high, voltage is large and ON-resistance is low. Thus, a circuit is configured with discrete parts such as FETs and resistors. On the other hand, scanning pulses (Vw) are applied to the scanning electrodes
3
respectively at different timings, and accordingly, the number of circuits should be the same as that of the scanning electrodes
3
. Therefore, IC with high withstand voltage is used to superimpose scanning pulses by using diode circuit in a mixer
20
and apply them to the scanning electrodes
3
. Furthermore, IC with high withstand voltage is used because data electrodes
7
need to be applied data pulses independently according to the display data.
The reason for using ICs with high withstand voltage is that since the scanning electrodes
3
and the data electrodes
7
are driven independently, a lot of circuits are required, and since output electric current is relatively small, integration is enabled and the drive circuit may be cost down.
The driving pulse trains SUS, SCn and DATA are divided respectively into a pre-discharge (priming) period Tp, write-in discharge (addressing) period Tw and sustaining discharge period Ts, respectively. The priming period Tp applies priming pulses between the scanning electrodes
3
and the sustaining electrodes
4
to generate discharge and to crease charged particles and excitation particles such as ions and electrons as well as to control wall charges on the scanning electrodes
3
, sustaining electrodes
4
and data electrodes
7
with fixed amounts, thereby serving to stabilize the discharge of the addressing period Tw.
During the priming period Tp, all scanning electrodes
3
are applied with the scanning pulses successively, and write-in discharges are generated, in relation with the data electrodes
7
, by means of data pulse to be applied in accordance with the display data, thereby serving to address the display data as the wall charges.
During the sustaining discharge period Ts, the sustaining pulses A shown in
FIG. 6
are applied to the scanning electrodes
3
while the sustaining pulses B shown in
FIG. 6
are applied to the sustaining electrodes
4
, thereby sustaining the display discharge. Thus, the write-in discharge is created only in the pixel issuing luminescence according to the display data between the scanning electrodes
3
and the data electrodes
7
so as to form the wall charges on the protective layer
13
on the side of the scanning electrodes
3
. Based on this information, the discharge is sustained between the scanning electrodes
3
and the sustaining electrodes
4
to obtain desired luminescence. The display is performed by exciting selectively the red, green and blue phosphors
11
by ultraviolet rays created by the sustaining discharge.
Since surface discharge type plasma display panel uses the ultraviolet rays generated by discharging as mentioned above, it requires high voltage pulse trains of such frequency of several hundred kHz having a value of wave height of around several hundred voltages, and further it requires relatively high power. In the sustaining discharge period, therefore, the sustaining pulses B are applied to the scanning electrodes
3
as shown in
FIG. 6
, while the sustaining pulses A is applied to the sustaining
Nunomura Keiji
Ueoka Mitsuo
Awad Amr
Jankus Almis R.
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