Computer graphics processing and selective visual display system – Display driving control circuitry
Reexamination Certificate
1997-04-02
2001-06-05
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Display driving control circuitry
C345S055000, C345S082000
Reexamination Certificate
active
06243082
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention includes a display apparatus and a display method and, more particularly, a flat panel display apparatus and a flat panel display method. The invention is also concerned with a display apparatus constructed of a plurality of display devices disposed in the same vertical plane, suitable for a display panel for displaying characters, graphics, patterns, etc. Further, the invention pertains to a display method used in this type of display apparatus.
2. Description of the Related Art
Display apparatuses, such as display panels, can be categorized into large-sized display apparatuses for outdoor use, such as displays for traffic signs, guide signs, public relations, advertisement, time, date, etc., and small and medium-sized display apparatuses, such as monitors for machines used in offices, such as personal computers and word processors, and vehicle-loaded display panels. One type of such a known display apparatus is constructed using electro-optical conversion devices as display devices.
The display apparatuses of this electro-optical conversion type include flat panel display apparatuses and solid-state pixel display apparatuses, such as liquid crystal displays (LCD), plasma display panels (PDP), and electroluminescence displays (ELD). The flat panel display apparatus is constructed of a plurality of very minute display devices disposed in a plane in a two-dimensional matrix form and are operable according to the following dot sequential driving method. Only the very minute display devices located at the activated rows and columns are driven for a short period of time, and such activated rows and columns are sequentially shifted to adjacent display devices, which are then driven for a short period of time. This operation can be continuously repeated to form an image with a minimal number of drivers.
According to this method, the individual display devices are sequentially driven in a time-division manner. Accordingly, one display device forming each pixel is activated only for a short period of time allocated in a time-division manner to perform a display operation by means such as emitting light. Then, after a lapse of a certain period of given time, the light goes off.
FIG. 18
is a block diagram of the above conventional type of flat panel display apparatus.
FIG. 19
is a chart illustrating an image signal input into the flat panel display apparatus shown in FIG.
18
. An explanation will now be given of the known flat panel display apparatus with reference to
FIGS. 18 and 19
.
A flat panel display apparatus generally indicated by
51
has a pixel matrix
52
, a high-frequency gate driver
53
and a high-frequency signal driver
54
, both of which select one of the display devices arranged in rows and columns forming the pixel matrix
52
and excite the selected device, and a controller
55
to supply a display signal to both the drivers
53
and
54
.
Input into the controller
55
are an image signal Vd and horizontal/vertical synchronizing signals. The image signal Vd is formed of pixel signals arranged, as illustrated in
FIG. 19
, in the order of a column, row, and frame in a chronological order.
FIG. 19
shows that one frame image is constituted of 14 columns and 16 rows. For example, if a first frame image is represented as shown in
FIG. 3
, the image signal positioned at the fifth row and fourth column is on, while the adjacent image signal located at the fifth row and fifth column is off. Then, if a second frame image is indicated as illustrated in
FIG. 5
, the image signal located at the fifth row and fourth column is turned off, while the adjacent image signal at the fifth row and fifth column is turned on.
The image signal Vd, which is modulated by the pixel signals of all the pixels arranged in matrix form, as noted above, has a high frequency ranging from several MHz to several dozens of MHz. Hitherto, images are displayed in such a manner that the high-frequency gate driver
53
and the high-frequency signal driver
54
send output signals to the individual display devices and drive them based on an input high-frequency image signal.
Since the frequency of the image signal rises to as high as several dozens of MHz, the individual display devices are turned on or off in a very short period of time, i.e., the excitation (for example, luminous) period for each display device is extremely short. Accordingly, it is necessary that both the drivers
53
and
54
activate or inactivate a relatively large drive current in a short period of time.
This aspect will be described in greater detail. For example, in a SVGA-specification driver LSI, driving at lower voltages as low as 3.3 V is being promoted due to electromagnetic noise caused by a high-frequency signal input into the driver LSI.
Further, as terminals are mounted on only one side of a panel in response to a higher-definition panel and a narrower-framed module, a driving operation is inevitably performed by using only one side of the panel, thereby increasing the frequency of a signal into the driver LSI. More specifically, although a driving operation is conventionally performed by use of comb-like terminals extended from both upper and lower sides of a panel, all the terminals are now formed only on the upper side of a panel. This makes it possible to reduce the frame area by an amount equal to the lower side of the panel. Because of the construction of a single-sided-driving display apparatus, nearly half of the frame area can be reduced, but on the other hand, the increased frequency band increases the burden on the driver. Additionally, the dot clock speed should be increased in order to achieve high resolution.
The input frequency of a VGA-specification (640 by 480 pixels) single-sided-driving TFT panel having a 26-cm diagonal dimension (10.4 model), which is the mainstream of notebook personal computers, is as high as 25 MHz. Further, the input frequency of a SVGA-specification (800 by 600 pixels) single-sided-driving TFT panel is even as high as 40 MHz, which sharply increases electromagnetic noise. If a XGA-specification (1024 by 768 pixels) single-sided-driving TFT panel is employed, the input frequency even reaches as high as 65 MHz, thereby further increasing electromagnetic noise, causing a serious problem. As a consequence, some measures must be taken in the overall drive circuit of a liquid crystal panel, for example, a smoothly formed input waveform is implemented, to reduce electromagnetic noise.
Another type of conventional display apparatus, which is an electro-mechanical type, has been developed or proposed. As an example of the above type of apparatus, a large-sized display apparatus for outdoor use or a medium-sized display apparatus, such as the one disclosed in Japanese Patent Publication No. 57-31147, is proposed. This display apparatus is constructed, as shown in
FIG. 20
, in the following manner. A cage-like rotary display unit
151
formed of a synthetic resin material has side faces
152
and
153
opposedly facing each other on which display surfaces of different colors, for example, red and white, are formed. This display unit
151
is rotated by a motor
154
so as to position either of the side faces
151
or
152
on the upper side of
FIG. 20
in response to the on or off state of pixels, so that the red or white color can be visually recognized.
Moreover, a small-sized display apparatus, such as the one disclosed in Japanese Patent Publication No. 61-58835, is configured, as shown in
FIG. 21
, in the following manner. A movable segment
61
provided for part of a rotatable permanent magnet
62
masks a colored display plate
60
in accordance with the rotation of the permanent magnet
62
. Accordingly, desired numerical and characters can be displayed by an unmasked portion of the display plate
60
. The permanent magnet
62
is rotated by magnetization of an electromagnet
64
achieved by supplying power to a magnetization coil
63
.
More specifically, the electromagnet
64
is magnetized by a
Nguyen Jimmy H.
Shalwala Bipin
Sonnenschein Nath & Rosenthal
Sony Corporation
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