Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1999-12-09
2002-11-19
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C315S169400
Reexamination Certificate
active
06483488
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a display apparatus, wherein an electrooptic layer is driven by the use of plasma to select pixels, and to a method of driving the display apparatus.
BACKGROUND OF THE INVENTION
In recent years, various display apparatuses are available. Among them are display apparatuses having a PDP (Plasma Display Panel), display apparatuses having a TFT (Thin-Film Transistor) liquid crystal display, and display apparatuses having a plasma-addressing liquid crystal display (hereinafter called PALC display). The PALC display apparatus, in particular, attracts attention, because it can provide a large screen.
FIG. 1
shows the basic structure of the PALC display apparatus.
As shown in
FIG. 1
, the PALC display apparatus comprises a liquid crystal layer
101
made of electrooptic material, plasma chambers
102
, and a thin dielectric sheet
103
that is made of glass or the like. The layer
101
opposes the chambers
102
, with the sheet
103
interposed between it and the chambers
102
.
The plasma chambers
102
are defined by a plurality of parallel grooves
105
made in a surface of a glass substrate
104
. The chambers
102
are filled with gas that can be ionized. A pair of electrodes
106
and
107
, which extend parallel to each other, is provided in each of the grooves
105
. The electrodes
106
and
107
of each pair are an anode A and a cathode K, which ionize the gas in the plasma chamber
102
, thereby generating discharge plasma.
The liquid crystal layer
101
is held between the dielectric sheet
103
and a transparent substrate
108
. Transparent electrodes
109
are provided on that surface of the transparent substrate
101
which opposes the liquid crystal layer
101
. The transparent electrodes
109
extend at right angles to the grooves
105
that define the plasma chambers
102
. The intersections of the plasma chambers
102
and the transparent electrodes
109
correspond to pixels.
In this display apparatus, the plasma chambers, in which plasma discharge is effected, are sequentially scanned, and a signal voltage is applied to the transparent electrodes
109
contacting the liquid crystal layer
101
as the plasma chambers are thus scanned. As a result, the pixels hold the signal voltage, thereby driving the liquid crystal layer
101
.
Each groove
105
, or each plasma chamber
102
, corresponds to one scanning line. The chamber
102
is divided into discharge regions, which define unit-scanning spaces.
FIG. 2
is a schematic representation of the PALC display apparatus, illustrating the arrangement of the transparent electrodes
109
, anode electrodes A and cathode electrodes K.
The transparent electrodes
109
are connected to a transparent electrode driving section, which comprises a data driver circuit
110
and an output amplifiers
111
. The analog voltage output from each amplifier
111
is supplied as a liquid-crystal drive signal.
The cathode electrodes K
1
to Kn are connected to a cathode driving section, which comprises a data strobe circuit
112
and output amplifiers
113
. More specifically, the cathode electrodes K
1
to Kn are connected to the output amplifiers
113
, respectively. Each output amplifier
113
outputs a pulse voltage, which is applied, as a data strobe signal, to the corresponding cathode electrode. A reference voltage (i.e., ground voltage) is applied to all anode electrodes A
1
to An.
The anode electrodes A and the cathode electrodes K are connected as is illustrated in FIG.
3
.
The display apparatus has a scanning control circuit
114
, which is connected to the data driver circuit
110
and data strobe circuit
112
. The scanning control circuit
114
serves to display an image on the entire screen of the display apparatus. The circuit
114
is designed to adjust the functions of the data driver circuit
110
and data strobe circuit
112
in order to designate addresses of lines, one after another, for all columns of pixels in the liquid crystal layer
101
.
In the display apparatus, the liquid crystal layer
101
operates as a capacitor for sampling the analog voltage applied to the transparent electrodes
109
. The discharge plasma generated in the plasma chambers
102
operates as a sampling switch. As the layer
101
and the plasma so operate, the display apparatus displays images.
In the PALC display apparatus, the plasma channels may be sequentially scanned, from the uppermost one to the lowermost one, and the liquid-crystal drive signal may be supplied to the liquid crystal layer
102
(more specifically, to the transparent electrodes
109
) as the plasma channels are so scanned. In this case, plasma discharge takes place between the anode electrodes A, on the one hand, and the cathode electrodes K, on the other, as is illustrated in FIG.
4
.
FIG. 5
shows the waveform of the liquid-crystal drive signal supplied to the transparent electrodes
109
in this case. The numbers identifying the anode electrodes A and cathode electrodes K in
FIG. 4
indicate the order in which the anode electrodes and the cathode electrodes are arranged in the same column. Each letter x in
FIG. 4
shows the position where plasma discharge occurs between one cathode electrode K and the corresponding anode electrode A. The numbers added to the letters x represents the order in which the plasma discharge takes place.
For instance, plasma discharge occurs at position x
1
between the cathode electrode K
1
and the anode electrode A
1
, and at position x
2
between the cathode electrode K
2
and the anode electrode A
2
. Similarly, plasma discharge takes place at position xm between the cathode electrode Km and the anode electrode Am, at position xm+1 between the cathode electrode Km+1 and the anode electrode Am+1, and a position xm+2 between the cathode electrode Km+2 and the anode electrode Am+2.
In
FIG. 5
, LCm is the waveform of the liquid-crystal drive signal that is supplied to the transparent electrodes
109
arranged in the horizontal direction. L
1
to L
9
in
FIG. 5
indicate the times at which horizontal scanning is performed. In the case illustrated in
FIGS. 4 and 5
, the anode electrodes A are always at a constant potential (0 V), while the potentials of, for example, the cathode electrodes Km, Km+1 and Km+2 are switched between 0 V and −400 V, thereby to cause discharge in these plasma channels.
The manufacturing costs of the drive circuit incorporated in the PALC display apparatus is high. It is therefore difficult for the PALC display apparatus to avail commercially. The manufacturing costs of the drive circuit is high for two reasons. Primarily, the drive circuit has many output terminals. Secondly, the drive voltages output from these output terminals are high. In a PALC display apparatus of VAG (Video Graphics Array) standard, which has image resolution of 640×480 pixels, the drive circuit needs to have 480 discharge output terminals to achieve the switching of the cathode electrodes. In addition, the drive voltage output from each output terminal may amount to 400 V in some cases.
SUMMARY OF THE INVENTION
The present invention has been made in view of the foregoing. The object of the invention is to provide a PALC display apparatus that can be manufacture at low cost and display images of high quality, and to provide a method of driving the PALC display apparatus.
According to the invention, there is provided a display apparatus which comprises: a first electrode layer having a plurality of first electrodes extending substantially parallel to one another; a second electrode layer having a plurality of second electrodes extending substantially parallel to one another, each composed of at least one pair of discharge electrodes, and arranged with the second electrodes opposing the first electrodes and extending to the first electrodes; and electrooptic layer provided between the first electrode layer and the second electrode layer and substantially contacting the first electrode layer, to be driven by said at least one pair of d
Piziali Jeff
Shalwala Bipin
Sonnenschein Nath & Rosenthal
Sony Corporation
LandOfFree
Display apparatus and method of driving the display apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Display apparatus and method of driving the display apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Display apparatus and method of driving the display apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2991869