Computer graphics processing and selective visual display system – Display peripheral interface input device
Reexamination Certificate
1996-08-06
2001-03-13
Hjerpe, Richard A. (Department: 2674)
Computer graphics processing and selective visual display system
Display peripheral interface input device
C345S033000, C345S034000, C345S111000, C345S182000, C345S182000, C345S182000, C345S504000, C345S519000
Reexamination Certificate
active
06201529
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display apparatus and a method of driving the same, and, more particularly, to a liquid crystal display apparatus which displays color images using the birifringence of a liquid crystal.
2. Description of the Related Art
A liquid crystal display (LCD) panel for a color LCD apparatus generally has a liquid crystal (LC) cell, a pair of polarization plates sandwiching the LC cell, and a back light (illumination light source) located outside one of the polarization plates. The LC cell comprises a pair of transparent substrates with transparent electrodes formed on the opposing surfaces of the transparent substrates, and a liquid crystal sandwiched between the transparent substrates. One of the transparent substrates is provided with a color filter.
Conventional LCD apparatuses are driven by enabling or disabling the drive voltage to be applied between the opposing transparent electrodes to control the alignment state of the liquid crystal and causing the light from the back light to transmit or not to transmit through the LCD panel. When passing the color filter, the light from the back light is colored to the color of that color filter, thereby displaying a color image.
The light transmittance of the color filter is low, so that the conventional color LCD apparatus suffers a large light loss at the color filter, making the display darker.
In a reflection type LCD apparatus which employs a reflector in place of the back light, in particular, the incident light is absorbed by the color filter twice, before and after it is reflected at the reflector. This absorption darkens the display. It is therefore difficult to employ a color-filter using a color LCD panel in the reflection type LCD apparatus.
Under these circumstances, there has recent been developed an electrically controlled birifringence (ECB) type LCD apparatus which can display color images without using any color filter.
Since this ECB type LCD apparatus employs a different coloring method from that of the LCD apparatuses using a color filter, it cannot be driven directly by using an RGB signal which is used to drive an ordinary color LCD device using a color filter. Accordingly, the conventional ECB type LCD apparatus disregards color information and uses luminance information to provide the two-color (ON and OFF) display.
As another possible approach, the applied voltage may be altered in accordance with a display color which is specified by an RGB signal. This method, however, requires a process of temporarily developing a display image in a frame buffer and then changing the applied voltage according to the display color. This method therefore needs a relatively large-capacity frame buffer and involves complex data processing.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a liquid crystal display apparatus and a method of driving the same which accomplish multi-color display without a color filter.
It is another object of the present invention to provide a liquid crystal display apparatus and a method of driving the same by which display color is selectable pixel by pixel in the liquid crystal display apparatus.
It is further object of the present invention to provide a liquid crystal display apparatus and a method of driving the same which accomplish gradation (color) display without a large frame buffer.
To achieve the above objects, a liquid crystal display apparatus according to a first aspect of the present invention is a liquid crystal display apparatus for displaying different colors in accordance with an applied voltage which changes a liquid crystal retardation, said apparatus comprising:
a first display area having a display area of m-rows and n-columns for displaying a plurality of characters formed with a plurality of dot-shaped segments;
a second display area for displaying an image formed with a plurality of arbitrarily-shaped segments; and
drive means for specifying display positions, character type and character colors with respect, to the first display area, and for specifying display colors of each arbitrarily-shaped segment with respect to the second display area.
Said drive means comprises:
character code storage means, comprising a character code memory having a memory-area of m-rows and n-columns corresponding to said first display area, for storing character codes in association with the display positions of said characters on said first display area;
character color data storage means, comprising a character color data memory having a memory area of m-rows and n-columns, for storing display color data of characters in association with an address of each character code stored in said character code storage means;
display color designation means for displaying each character on said first display area in a color corresponding to the stored display color data;
image color data storage means, comprising an image color memory whose memory bits correspond to bits representing the arbitrarily-shaped segments and image color data of the image to be formed, for storing image color data corresponding to each segment to be displayed on said second display area; and
image color designation means for displaying each segment on said second display area in a color corresponding to the stored image color data.
Said image color data storage means stores each bits of said image color data: (i) at relatively same positions in adjoining memory areas of said image color memory, or (ii) in adjoining positions in a memory area of said image color memory after dividing said image color data.
At least one of said character color data storage means and said image color data storage means stores p-bit display color data for designating any of 2
p
colors, where p is a positive integer; and
said display color designation means and said image color designation means convert said p-bit display color data into q-bit display color data where q is a positive integer having a value representing an effective value of the applied voltage necessary for the display color designated by said p-bit display color data, and comprise drive pulse width setting means for setting a pulse width of a drive voltage to be applied to the liquid crystal based on said q-bit display color data.
To further achieve the above objects, a method of driving a liquid crystal display apparatus according to a second aspect of the present invention is a method of driving a liquid crystal display apparatus for displaying different colors in accordance with applied voltages which change a liquid crystal retardation, said liquid crystal display apparatus including a first display area having a display area of m-rows and n-columns for displaying a plurality of characters formed with a plurality of dot-shaped segments, and a second display area for displaying an image formed with a plurality of arbitrarily-shaped segment, said method comprising the steps of:
designating an address in a character code memory having a memory area of m-rows and n-columns corresponding to display position of a character on the first display area;
storing character code data of said character at said designated address in said character code memory with respect to the first display area;
storing display color attribute data of the character in a display color data memory having a memory area of m-rows and n-columns in accordance with the address of the character code stored in said character code memory with respect to the first display area;
storing image color attribute data corresponding to each segment in an image color memory whose memory bits correspond to bits representing arbitrarily-shaped segments and image color data of an image with respect to the second display areas; and
generating segment drive signals in accordance with each stored color attribute data with respect to the first and second display areas.
Said step of storing image color attribute data comprises storing each bit of said image color attribute data: (i) in bits at relative
Casio Computer Co. Ltd.
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Hjerpe Richard A.
Tran Henry N.
LandOfFree
Liquid crystal display apparatus and method of driving the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid crystal display apparatus and method of driving the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal display apparatus and method of driving the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499516