Computer graphics processing and selective visual display system – Display driving control circuitry – Intensity or color driving control
Reexamination Certificate
1998-11-04
2003-12-02
Wu, Xiao (Department: 2674)
Computer graphics processing and selective visual display system
Display driving control circuitry
Intensity or color driving control
C345S698000, C345S215000, C345S098000
Reexamination Certificate
active
06657640
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image display apparatus.
2. Related Background Art
In recent years, as the image information amount of a personal computer increases, the display monitor has a higher resolution and a larger number of gradation levels, and processes various composite information such as TV information. With the advent of monitors such as a liquid crystal display and a plasma display other than a CRT, image information is often digitized and processed.
FIG. 13
is a block diagram showing an image display apparatus using a liquid crystal panel as an image display unit.
Referring to
FIG. 13
, the image display apparatus comprises an input terminal
1
for an analog video signal, an A/D converter
2
, an image processing unit
3
for processing a digital image and converting it to a signal suitable for the liquid crystal panel, a D/A converter
4
, an image memory
5
used to process an image by the image processing unit
3
, an input terminal
6
for a video signal synchronizing signal, and a drive pulse generator
7
for generating various drive and control pulses from the synchronizing signal. Pulses from the drive pulse generator
7
serve as control pulses for the A/D converter
2
, D/A converter
4
, and image processing unit
3
, and a drive pulse for an image display unit
8
. The analog signal converted by the D/A converter
4
serves as an image input signal for the image display unit
8
.
FIG. 14
is a circuit diagram showing the arrangement of the liquid crystal panel as an example of the image display unit
8
. Referring to
FIG. 14
, a shift register (HSR)
9
functions as a horizontal scanning circuit and receives a start pulse (&phgr;HST)
10
and a horizontal shift clock (&phgr;HCK)
11
. A shift register (VSR)
12
functions as a vertical scanning circuit and receives a start pulse (&phgr;VST)
13
and a vertical shift clock (&phgr;VCK)
14
. The liquid crystal panel further comprises a video signal input terminal
15
, a common signal line
36
, a vertical signal line
17
, transfer switches
16
and
19
made up of MOS transistors, a gate line
18
, a liquid crystal cell
20
, a capacitor
21
for holding the charge, and a liquid crystal counter electrode (common electrode)
22
.
Input video signals are sequentially selected by the horizontal shift register (HSR)
9
and transferred to the vertical signal lines
17
via the transfer switches
16
. At this time, the vertical shift register (VSR)
12
selects a given gate line
18
. Accordingly, a transfer switch
19
of a specific pixel selected as a matrix by the horizontal shift register (HSR)
9
and the vertical shift register (VSR)
12
is selected. The liquid crystal cell
20
and capacitor
21
are charged with the potential of the video signal of the specific pixel with respect to the potential of the counter electrode
22
, thereby performing pixel display.
Along with the development of recent device technology, the number of pixels and the number of gradation levels in image display devices such as the liquid crystal panel greatly increase, and the data amount processed in the image display apparatus also increases. For example, the data amount is 5.5 Mbits/frame in VGA class (640×480 pixels and three R, G, B colors of 6-bit precision), 18.9 Mbits/frame in XGA class (1,024×768×8 bits×three colors), and 31.5 Mbits/frame in SXGA class (1,280×1,024×8 bits×three colors). As the resolution and the number of gradation levels increase, the cost of the memory occupies a large proportion of the total cost.
However, the frame memory of a conventional image display apparatus, which has an amount necessary for the resolution of the image display unit, is mounted on the same board as the image processing unit. When an upgraded product having a larger number of display pixels is to be manufactured, a board
26
(dotted region in
FIG. 13
) for mounting a memory in size corresponding to the resolution of a new image display unit must be redesigned. The design load and uncommon components increase the cost.
Also, the board cannot be commonly used between a single-function product having only a frame memory, and an advanced-function product having a picture-in-picture function, a frame dividing function, and the like using many memories.
SUMMARY OF THE INVENTION
It is an object of the present invention to realize the lineup of a plurality of grades of products at a low cost by sharing the region except for the memory which occupies a large proportion of the total cost and by attaining a memory expandable arrangement in increasing the resolution and the number of functions in the display.
To achieve the above object, according to the present invention, there is provided an image display apparatus having image processing means for processing a digital signal, data memory means for storing data corresponding to at least one frame of an image, and image display means for displaying the image on the basis of an image signal from the image processing means, wherein the data memory means can be dismounted.
According to the present invention, there is provided an image display apparatus having image processing means for processing a digital signal, data memory means for storing data corresponding to at least one frame of an image, and image display means based on an image signal from the image processing means, wherein at least part of the data memory means can be added/removed.
According to the present invention, a non-data-memory means such as the image processing unit other than the data memory means can be shared by a plurality of products having different resolutions, different numbers of gradation levels, or different functions in the image display means. The development cost of the product can be reduced to easily realize cost reduction. The memory is divided in correspondence with divisional driving unique to the image display means, and part of the memory is dismounted or added/removed to simplify the system arrangement.
The present invention is applicable to any image display apparatus involving digital image processing such as a transmission or reflecting display, liquid crystal display, or display using FED (Field Emission Device) or SCE (Surface Conductive Emission Device), or PDP (Plasma Display Panel).
REFERENCES:
patent: 5200863 (1993-04-01), Orii
patent: 5557691 (1996-09-01), Izuta
patent: 5724155 (1998-03-01), Saito
patent: 5790193 (1998-08-01), Ohmori
patent: 6145046 (2000-11-01), Jones
patent: 6147708 (2000-11-01), Suzuki et al.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Wu Xiao
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