Computer graphics processing and selective visual display system – Display peripheral interface input device – Light pen for fluid matrix display panel
Reexamination Certificate
1997-05-27
2001-05-22
Saras, Steven (Department: 2675)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Light pen for fluid matrix display panel
C345S100000, C345S099000, C348S556000
Reexamination Certificate
active
06236388
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image display system utilizing an active-matrix-type liquid-crystal panel or the like as a display. More particularly, the present invention relates to an image display system capable of appropriately displaying image signals having different resolution standards.
2. Description of the Related Art
Referring to
FIG. 6
, an example of a conventional active-matrix-type display panel will be described briefly. As shown in the figure, this display panel comprises a driving substrate
101
, a counter substrate
102
, and an electro-optic material
103
held between the driving substrate
101
and the counter substrate
102
. As the electro-optic material
103
, liquid crystal is widely used. A screen section
104
and a peripheral circuit section are integrated on the driving substrate
101
. The peripheral circuit section (unnumbered) is divided into a vertical scanning circuit
105
and a horizontal scanning circuit
106
. Further, terminal sections
107
for external connection are formed on the upper end of the driving substrate
101
. The terminal section
107
is connected to the vertical scanning circuit
105
and the horizontal scanning circuit
106
via wiring
108
. Meanwhile, a counter electrode (not shown) is formed entirely on the inner surface of the counter substrate
102
. Gate lines
109
along the row direction and signal lines
110
along the column direction are formed on the screen section
104
. The gate lines
109
are connected to the vertical scanning circuit
105
, and the column signal lines
110
are connected to the horizontal scanning circuit
106
. Pixels formed of pixel electrodes
111
and thin-film transistors
112
are integrated in the intersection portions of the vertical scanning circuit
105
and the horizontal scanning circuit
106
. The vertical scanning circuit
105
includes a transferring stage for transferring a vertical start signal in sequence which is input from an external source in synchronization with a vertical clock signal which is input similarly from an external source, and selects in sequence the rows of pixels provided on the screen section
104
. The horizontal scanning circuit
106
also includes a transferring stage which operates in response to a control signal, such as a horizontal start signal or a horizontal clock signal, which is input from an external source, and distributes image signals supplied from an external source in sequence to the columns of pixels and writes the image signals into selected pixels.
Image signals supplied from an external source have various standards concerning resolution. Examples of standards for television video signals include NTSC and PAL standards. It is assumed that the screen section of the display panel shown in
FIG. 6
has a pixel array conforming to the NTSC standard. In cases where video signals of, for example, a PAL standard, are displayed on this display panel, conventionally, scanning line conversion of PAL video signals is performed so as to perform what is commonly called thinning-out driving of pixel rows. For this purpose, a field memory for temporarily storing video signals is required. Further, in cases where video signals conforming to a normal standard such that the aspect ratio of the screen section is determined at 4:3 are displayed on a display panel conforming to a wide standard such that the aspect ratio is determined at 16:9, a method has already been conceived in which aspect conversion from 16:9 to 4:3 is performed by causing both the left and right end portions of the screen section to be displayed in black. Furthermore, in recent years, an active-matrix-type display panel has been applied to displays for computer graphics. In this case also, a personal computer outputs image signals having various resolution standards. However, image signals output from a personal computer are signals previously formed in units of dots. If scanning line conversion similar to that of television video signals is performed in conformance with the resolution standard, what is commonly called moire occurs on the screen. More specifically, if the sampling timing of image signals shifts in terms of phase from the data array in dot units during the scanning line conversion process, phase differences of a relatively large cycle occur in the pixel array of the screen, and these phase differences appear as moire. Therefore, in order to suppress moire, it is necessary to cause the resolution of image signals supplied from the personal computer or the like to coincide with the pixel array provided on the screen of the display panel. In this case, if image signals (e.g., image signals of a VGA standard) having a relatively low resolution are displayed on a display panel designed for image signals (e.g., image signals of a SVGA standard) having a relatively high resolution, pixels to which image signals are not written remain in the peripheral portion of the screen, causing a blank area to occur. In order to improve the appearance of the screen, it is preferable that the blank area which is other than the display area be displayed black. Conventionally, to make such a black display, black display dot data is inserted among the image signals beforehand. For the purpose of performing such image signal processing, a field memory or a frame memory is required in the components of the image display system, causing problems in that the system configuration becomes complex and the cost is increased.
SUMMARY OF THE INVENTION
To these ends, according to one aspect of the present invention, there is provided an image display system, comprising: a driver for supplying a plurality of types of image signals having different resolution standards and a black signal independent of these image signals; a display panel having incorporated therein a screen formed of pixels arrayed in a matrix, a vertical scanning circuit provided with a first transferring stage for selecting the rows of the pixels in sequence, a horizontal scanning circuit provided with a second transferring stage for distributing image signals supplied from the driver in sequence to columns of the pixels and writing the image signals into selected pixels, and a horizontal auxiliary circuit for distributing a black signal supplied from the driver to columns of the pixels and writing the black signal into selected pixels; a timing generator for supplying a control signal to each circuit of the display panel according to the resolution of the image signals supplied from the driver in order to control the operation thereof; and first selector switches of the first transferring stage, which selector switches are incorporated within the vertical scanning circuit and cause the display area to change in accordance with the control signal.
Preferably, the first selector switch writes a black signal into the rows of pixels included in the upper and lower portions of the blank area of the display area during the vertical blanking period of the image signals.
Preferably, the horizontal scanning circuit has incorporated therein second selector switches of the second transferring stage, which selector switches cause the display area to change in accordance with the control signal.
Preferably, the second selector switch writes a black signal into the columns of pixels included on the right and left sides of the blank area when the black signal independent of the image signals is supplied from the driver.
Preferably, the display panel uses a liquid crystal as an electro-optic material.
According to another aspect of the present invention, there is provided a method of driving an image display apparatus comprising a screen formed of pixels arrayed in a matrix, a vertical scanning circuit provided with a first transferring stage for selecting the rows of the pixels in sequence, a horizontal scanning circuit provided with a second transferring stage for distributing image signals in sequence to columns of the pixels and writing the image signals into selected pixels, a
Hayashi Yuji
Iida Masayuki
Awad Amr
Kananen Ronald P.
Rader Fishman & Grauer
Saras Steven
Sony Corporation
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