Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1999-01-25
2001-11-20
Saras, Steven (Department: 2675)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S103000
Reexamination Certificate
active
06320567
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to display devices, and more particularly to large-screen projection display apparatus incorporating a thin display panel for use in producing an image of high resolution for projection onto a viewing screen. The invention also relates to active-matrix color liquid crystal display devices for use in color image projector systems.
2. Description of the Prior Art
Conventionally, display devices using a liquid crystal display (LCD) panel are well known for use in large-screen color image projector systems. The display devices of this type are designed to produce a picture image for display on an associated viewing screen by modulation of light rays using the optical characteristics of liquid crystal materials as sealed in the LCD panel. The presently available LCD display devices come with a display area consisting of an array of rows and columns of picture elements or “pixels” as organized into a planar matrix form; for example, a matrix of 640 by 480 dots having a horizontal array of 640 pixels and vertical array of 480 pixels.
Typically, the LCD display devices are driven in such a manner that information bits are written at respective pixels arrayed in a matrix while sequentially scanning the same causing the liquid crystal at an intended pixel to change in optical response characteristic to finally attain display of a picture image on the screen.
One prior known LCD display scheme on an associated screen is illustrated in
FIG. 5
, which is of an active-matrix LCD panel with a matrix of m×n pixels, where “m” and “n” are integers. The display operation thereof is as follows. Information is first written into a selected pixel at the upper left address (0, 0) in the uppermost row on the display screen. Then, information is written into its adjacent pixel at a successive address (1, 0). Such writing of information will be sequentially performed with respect to the remaining pixels in the first row while these are being subject to scanning.
After completion of information writing for the first row of pixels, similar write operation is then sequentially carried out with respect to the following, second row of pixels. In this way, the sequential write operation will be repeated up to the final pixel row on the LCD screen of FIG.
5
. In the information write procedure formation of one display image is terminated upon completion of information write with respect to the “last” pixel with address (m, n) as located at the lower right corner of the display screen. A resultant one-screen image is called the “frame.” Typically, this frame will be rewritten or “refreshed” on the screen for thirty times per second.
To attain the aforesaid simple sequential write operation for LCD display, peripheral driver circuitry (generally integrated on an IC chip) is employed which serves to store data representative of every horizontal line image and to supply such stored one-line scan image data to a corresponding part of active-matrix region with each horizontal line as a unit. This display drive technique is known as the “line sequence” scheme in the art.
As a further advanced arrangement, an LCD display device is known which incorporates an active-matrix region(s) and associative peripheral driver circuits, all of which are integrated on a single substrate that may be made of silicon, glass, or the like. This may enable accomplishment of reduction in thickness and in size, resulting in a decrease in manufacturing cost. However, the prior art is encountered with a serious problem in that the operation frequency is extraordinarily increased forcing the peripheral circuits to operate at higher rate accordingly. In other words, as the operation frequency required for associative horizontal scanning controller circuits becomes equivalent to (m×n×30) Hz, it is required that the controllers operate at extra high speed. By way of example, in the case of a 640×480 dot active-matrix region, it should be required that the horizontal scan controller operate at approximately 10 MHz rate or higher in order to achieve successful horizontal scanning of the active-matrix region.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a new and improved display device avoiding one or more problems as faced with the prior art.
It is another object of the invention to provide an improved display device capable of reducing the operation frequency without adversely affecting the quality of an image displayed.
It is yet another object of the invention to provide an improved large-screen projection display apparatus incorporating integrated peripheral circuitry capable of reducing the operation frequency without having to degrading displayable images in quality.
It is still another object of the invention to provide an improved active matrix-based LCD panel for use in projecting an image of high resolution on a large screen having a set of peripheral driver circuits integrated on a substrate, capable of decreasing the operation frequency while permitting achievement of enhanced image quality as displayed on the screen.
In accordance with one aspect of the instant invention, a display apparatus includes at least two active matrix regions for formation of an image, first and second horizontal scan controller circuits for providing horizontal scan controls to the active matrix regions respectively, and a vertical scan controller circuit for providing vertical scanning control in common to the active matrix regions. The active matrix regions, the horizontal scan controllers and the common vertical scan controller are all integrated together on the same substrate. Certain images being formed in the active matrix regions are superimposed with each other for production of a resultant image to be projected onto an associated viewing screen, wherein the first and second horizontal scan controllers are specifically arranged such that these operate at a decreased frequency being equivalent in value to half the inherent horizontal scan frequency of an image for projection.
In one illustrative embodiment drawn to the above features, six (two by three) separate active matrix regions for definition of RGB color images therein are disposed on the principal plane of a substrate, which regions are organized into a first group of three active matrix regions and a second group of three regions. In some occasions where monochrome images are to be displayed, or in situations that a color image is to be formed for display in a single active matrix region by use of an associative color filter assembly, a decreased number—two (2)—of active matrix regions are permissible for use therein.
In accordance with another aspect of the invention, the number of active matrix regions being subject to different horizontal scanning control may be increased up to any integer “m” more than 2.
More specifically, a display apparatus includes a substrate, integrated circuitry on the substrate including a prescribed number—i.e., “m”—-of active matrix regions for formation of an image, m horizontal scan controller circuits for performing horizontal scan controls with respect to the active matrix regions respectively, and a vertical scan controller circuit for providing common vertical scan control for the m active matrix regions. Respective images in the m active matrix regions are then superimposed with each other to generate and issue the resulting superimposed image for projection. Importantly, the m horizontal scan controllers operate at a specifically selected frequency that is equivalent to 1/m of the inherent horizontal scan frequency of an image for projection on the display screen.
A common principle for the two aspects of the invention is that a respective one of the horizontal scan controllers is arranged to operate at a specific timing that is different from that of any one of the others. In the both, it may alternatively be arranged that an optical shutter mechanism is employed enabling selection of a res
Hirakata Yoshiharu
Teramoto Satoshi
Alphonse Fritz
Fish & Richardson P.C.
Saras Steven
Semiconductor Energy Laboratory Co. Ltd
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