Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
2002-07-25
2004-06-01
Philogene, Haissa (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C345S204000
Reexamination Certificate
active
06744216
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to display devices, and in particular, to a method for arranging column and row drive lines in a display screen and a method for driving the lines.
2. Description of the Related Art
FIGS. 15A and 15B
show the structure of a liquid crystal panel (display device) of the related art. Driving circuits for the liquid crystal panel are typically large in physical size and may require modifications so as to avoid extending the overall physical size of the liquid crystal panel. Thus, to realize a high-definition and small liquid crystal panel, as shown in
FIGS. 15A and 15B
, the driving circuits for the data lines are divided into upper driving circuits
101
d
and lower driving circuits
101
e
, disposed on two opposite sides, namely, the upper and lower sides of the display screen
101
a.
FIG. 16
is an enlarged illustration of portion B of the display screen
101
a
shown in
FIG. 15A. A
first group of alternate ones of the data lines Y
1
to Y
480
in the display screen
101
a
are routed to the upper side of the display screen
101
a
. The remainder (i.e., the second group of alternate ones of the data lines Y
1
to Y
480
) are routed to the lower side of the display screen
101
a
. Hence, data lines leading to the upper side are connected to the upper driving circuits
101
d
, and data lines leading to the lower side are connected to the lower driving circuits
101
e
. Both driving circuits
101
d
and
101
e
are disposed on a single wiring plate P
101
and are connected to the display screen
101
a
by the wiring plate P
101
.
By disposing the data lines Y
1
to Y
480
to lead as shown in the configuration in
FIG. 16
, dot inversion can be realized. The polarities of drive voltages applied to liquid crystal displays are typically reversed many times per second to prevent any deterioration of image quality resulting from dc stress. Dot inversion, which is also known as spatial dot inversion, refers to the technique whereby the polarities of driving voltages applied to adjacent dots in the display screen
101
a
are inverted. By using this technique, spatial frequency can be increased and picture quality having minimized flickering can be obtained. The dot inversion can be realized, for example, by using a driving voltage output from the upper driving circuit
101
d
as a positive polarity, using a driving voltage output from the lower driving circuit
101
e
as a negative polarity, and performing polarity inversion for each line or each field. This operation is made possible by adding a line-inverting driving circuit to a one-sided driving circuit.
FIG. 17
is a block diagram showing the detailed structure of a display device of the related art. This display device includes a display screen
101
a
, an upper driving circuit
101
d
, a lower driving circuit
101
e
, and a scramble circuit
101
g
. The upper driving circuit
101
d
includes a digital-to-analog (D/A) conversion circuit SHU
12
for providing analog output signals to pixels Ga
1
and Ga
2
of the display screen
101
a
, a D/A conversion circuit SHU
34
for providing analog output signals to pixels Ga
3
and Ga
4
of the display screen
101
a
, a D/A conversion circuit SHU
56
for providing analog output signals to pixels Ga
5
and Ga
6
, etc. The lower driving circuit
101
e
includes a D/A conversion circuit SHD
12
for providing analog output signals to pixels Ga
1
and Ga
2
of the display screen
101
a
, a D/A conversion circuit SHD
34
for providing analog output signals to pixels Ga
3
and Ga
4
of the display screen
101
a
, a D/A conversion circuit SHD
56
for providing analog output signals to pixels Ga
5
and Ga
6
, etc. The display screen
101
a
in
FIG. 17
illustrates the pixels Ga
1
, Ga
2
, Ga
3
, etc., for only one line, and only data lines connected to dots constituting these pixels. Other data lines and pixel lines are omitted from the illustration for clarity purposes.
In order that the display screen
101
a
of the liquid crystal panel may show images in their natural colors, a scramble circuit
101
g
is required. Such a circuit changes the order of display data to be sent to the upper driving circuit
101
d
and the lower driving circuit
101
e
to correspond to the arrangement of color filters in the display screen
101
a
. Separate sets of bus lines are required to send display data from the scramble circuit
101
g
to the upper driving circuit
101
d
, and from the scramble circuit
101
g
to the lower driving circuit
101
e.
FIG. 18
is a timing chart for the display device of the related art. The chart shows the relationships among input data RD, GD, and BD for the scramble circuit
101
g
, display data UA, UB, and UC which are received by the upper driving circuit
101
d
after being transmitted from the scramble circuit
101
g
, and display data DA, DB, and DC which are received by the lower driving circuit
101
e
after being transmitted from the scramble circuit
101
g
. The scramble circuit
101
g
rearranges the order of the input data RD, GD, and BD to an order corresponding to the arrangement of color filters in the display screen
101
a.
To display an image properly on a display screen of a liquid display panel, i.e., so that the image natural colors are shown properly, the order of display data to be sent to driving circuits on two opposite sides of the display screen must be rearranged to the order corresponding to the arrangement of color filters in the display screen. To accomplish this, separate sets of display-data-bus lines must be formed on each of the two sides (e.g., an upper side and a lower side). This requires wiring areas for the bus lines on both sides, thus hindering size reduction of the display device.
In addition, since a scramble circuit generally includes logic circuits, logic circuits for the bus lines are required on both sides of the display screen. Furthermore, integrated circuits including scramble circuits of the above type require output pins for the bus lines on both sides of the display screen. This not only hinders reduction in the size of the display device, but also increases the display device cost.
Also, during inspection of the liquid crystal panel to diagnose problems found in a displayed picture, a portion causing the problem must be specified. Thus, in order to pinpoint the problem to one of the two sets of data lines leading to both sides of the display screen, driving of one set of data lines may be stopped.
In a structure in which data lines leading from a scramble circuit are connected in an alternating fashion to one of two sides of a display screen, as in the related art, when driving of data lines on one side is stopped, the data output from the driving circuits differs, depending on the which of the two driving circuits is involved. For example, if driving of data lines to an upper side driving circuit is stopped, black display data are output instead of, for example, a normally white liquid crystal panel. When a driving circuit on the lower side of the display screen is stopped, a stripe state occurs in which G, R, B, G, R, B, . . . are displayed on every other line. Accordingly, it is difficult to determine which side has a problem. Even if the side having the problem is determined, it is difficult to further localize the problem. For example, it is difficult to determine which data line from the side has a problem.
SUMMARY OF THE INVENTION
The present invention is made in view of the above-described problems, and it is an object of the present invention to provide a small, inexpensive display device which doesn't require a scramble circuit for scrambling display data to be sent to driving circuits on two sides of the display screen of the display device, and which displays natural color pictures.
It is another object of the present invention to provide a small, inexpensive display device that includes a reduced number of display-data-bus lines for sending display data to driving circuits.
It is another object of the present invention t
Fujiyoshi Tatsumi
Saito Junichi
Yamada Yukimitsu
A Minh D
Alps Electric Co. ,Ltd.
Beyer Weaver & Thomas
Philogene Haissa
LandOfFree
Display device requiring no scramble circuit 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 device requiring no scramble circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Display device requiring no scramble circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3359899