Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1997-07-02
2001-09-11
Brier, Jeffery (Department: 2779)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C315S169400
Reexamination Certificate
active
06288692
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an art for driving a display panel composed of a set of cells that are display elements having a memory function. More particularly, this invention is concerned with a display for achieving interlacing display using an alternating current (AC) type plasma display panel (PDP), and a driving method therefor.
2. Description of the Related Art
The above AC type PDP is designed to sustain discharge by applying a voltage wave alternately to two sustaining electrodes, and to glow for display. The present applicant has disclosed a plasma display for achieving interlacing display in Japanese Patent Application No. 8-194320. A driving method disclosed in the publication features that by selecting a voltage to be applied to X electrodes during addressing, it is selected in which of slits across each of Y electrodes discharge is triggered with discharge occurring between each pair of addressing electrodes and the Y electrodes. Consequently, wall charge can be produced in cells in each slit on the side in which discharge should be sustained. Sustaining pulses that are in phase with each other are applied to pairs of electrodes adjoining slits in which discharge is not induced, thus preventing incorrect discharge. A Y sustaining circuit and X sustaining circuit that are circuits for sustaining discharge are separated from each other and can mutually independently apply pulses for addressing and sustaining operations. In this plasma display, display lines associated with an odd field and even field do not affect each other. Partitions for defining display cells lengthwise need not be placed between each pair of the Y electrodes and X electrode. Consequently, the plasma display panel can enjoy the feature of high definition.
Furthermore, the Japanese Patent Application No. 8-194320 has disclosed a structure in which light-interceptive members are placed in slits, which are not involved in display, in order to prevent deterioration of display contrast deriving from discharge irrelevant to display. In a plasma display, discharge referred to as priming discharge is induced in order to facilitate smooth addressing discharge and sustaining discharge. In a prior art, for example, reset discharge to be carried out during a reset period plays the role of the priming discharge. This kind of priming discharge does not contribute to a display image but deteriorates display contrast. Using the above light-interceptive members, unwanted light irrelevant to display is intercepted.
The employment of the structure disclosed in the Japanese Patent Application No. 8-194320 obviates the necessity of placing partitions in parallel with the Y electrodes and X electrode. The plasma display panel can enjoy the feature of high definition. However, there is a problem that connection between a scan driver serving as a Y electrode selecting circuit and a Y sustaining circuit serving as a discharge sustaining circuit or a Y common driver becomes complex. For solving this kind of problem, the Japanese Patent Application No. 8-194320 has disclosed a display for achieving interlacing display in which two X electrodes are placed across each Y electrode, voltages are applied to the Y electrodes and odd-numbered X electrodes in order to induce discharge during an odd field, and voltages are applied to the Y electrodes and even-numbered X electrodes in order to induce discharge during an even field. A line between each pair of even-numbered and odd-numbered X electrodes is a complete non-display line. However, since no partition is placed, the feature of high definition can be provided. Besides, it is unnecessary to separate Y electrodes into two channels. This is advantageous because connection between a scan driver and Y sustaining circuit and connection between the scan driver and a panel becomes simple.
In the plasma display disclosed in the Japanese Patent Application No. 8-194320, assuming that a large voltage is applied to the Y electrodes and X electrodes for the purpose of full-screen writing during a reset period in the same manner as that in the prior art, when discharge induced is regarded as priming discharge, the priming discharge occurs at the same positions as display cells. As mentioned previously, priming discharge does not contribute to a display image but deteriorates display contrast. It is therefore preferred that light be intercepted. In the display disclosed in the Japanese Patent Application No. 8-194320, priming discharge occurs at the positions of display cells. A light-interceptive member cannot be placed at the positions. In the known display disclosed in the Japanese Patent Application No. 8-194320, there is a problem that display contrast cannot be improved fully.
In the foregoing prior art, reset discharge (priming discharge) occurs even in slits in which discharge is not induced. This leads to deteriorated contrast. In the prior art and others, since priming discharge is induced in display cells, the scale of discharge is as large as that of sustaining discharge. This poses a problem of a large power consumption.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a plasma display capable of preventing deterioration of display contrast deriving from priming discharge and of minimizing a power consumption, and a driving method therefor.
A plasma display of the present invention comprises: a plasma display panel in which first, second, and third electrodes are arranged alternately parallel to one another on a first substrate, and fourth electrodes are placed orthogonally to the first electrodes on the first substrate or a second substrate; a first electrode selection driving circuit for selectively driving the first electrodes; a second electrode driving circuit for driving the second electrodes and; a third electrode driving circuit for driving the third electrodes. In the plasma display, first display cells are formed at intersections between the first electrodes and second electrodes, and the fourth electrodes. Second display cells are formed at intersections between the first electrodes and third electrodes, and the fourth electrodes. The first display cells and second display cells alternately and repeatedly glow for display, thus achieving interlacing display. During a reset period, the second electrode driving circuit and third electrode driving circuit apply voltages to the second and third electrodes respectively so that priming discharge can be induced in third cells. The third cells for priming are formed with the second electrodes and third electrodes.
According to the present invention, priming discharge is induced in the third cells, which are not display cells, between the second and third electrodes. Light-interceptive members can be placed for light interception. Display contrast can therefore be improved. Moreover, since priming discharge is induced in the third cells T
1
that are not display cells, the scale of discharge can be diminished and a power consumption can be minimized.
Furthermore, light-interceptive members are placed in third slits that are gaps between the second and third electrodes.
During a sustaining discharge period, the first electrode selection driving circuit applies a first sustaining discharge pulse to the first electrodes. One of the second electrode driving circuit and third electrode driving circuit applies a sustaining discharge pulse that is out of phase with the first sustaining discharge pulse, and the other one thereof applies a given constant voltage or retains the associated electrodes at high impedance. The potential at slits (cells) in which discharge is not induced becomes less than a minimum discharge sustaining voltage. Incorrect discharge will therefore not occur.
Furthermore, the given constant voltage is substantially half of the voltage of the first sustaining discharge pulse. This is helpful in minimizing the potential at cells in which discharge is not induced.
Furthermore, first slits that are gaps between the first and sec
Asao Shigeharu
Kanazawa Yoshikazu
Koizumi Haruo
Blackman Anthony
Brier Jeffery
Fujitsu Limited
Staas & Halsey , LLP
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