Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2001-12-21
2004-06-01
Awad, Amr (Department: 2675)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S690000, C345S102000, C362S030000
Reexamination Certificate
active
06744416
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a field sequential liquid crystal display apparatus.
2. Description of the Related Art
A field sequential liquid crystal display apparatus has a construction in which a liquid crystal layer is sandwiched between a pair of front and rear substrates. Electrodes are formed on the opposing inner surfaces of these substrates. This apparatus comprises a liquid crystal display device, a plurality of light-emitting elements, and an illuminating unit. The liquid crystal display device forms a plurality of display elements which control the transmission of a light beam in a region where the electrodes of the pair of front and rear substrates oppose each other. The light-emitting elements are arranged at the back of this liquid crystal display device and emit light beams having a plurality of unit colors (e.g., three colors of red, green, and blue). The illuminating unit allows these unit-color light beams emitted by the light-emitting elements to enter the liquid crystal display device from the back side. To display an arbitrary color by temporal color mixing of a plurality of unit colors in the apparatus having this configuration, unit-color image data signals corresponding to these unit colors are sequentially supplied to the liquid crystal display device in each field for displaying one of these unit colors. During the period of one frame composed of a plurality of continuous fields, equal in number to the unit colors, for sequentially displaying different unit colors, the unit-color image data are sequentially written in the display elements of the liquid crystal display device. In addition, in accordance with this sequential write of the unit-color image data, the light-emitting elements of the plurality of unit colors are sequentially turned on. In this way, a color image (full-color image or multi-color image) is displayed.
In this field sequential liquid crystal display apparatus, the liquid crystal display device need not be equipped with any color filter, so there is no color absorption by the color filter. Also, this apparatus displays a color image by sequentially writing unit-color image data into all the display elements of the liquid crystal display device. Therefore, the apparatus can display bright, high-resolution color images compared to a liquid crystal display apparatus in which color filters of a plurality of colors corresponding to individual display elements of a liquid crystal display device are alternately arranged.
In the above field sequential liquid crystal display apparatus, one frame for forming one image is made up of three fields which display three colors, red, green, and blue. That is, one field for displaying one color is ⅓ of one frame, so data corresponding to one color must be written in and displayed by the liquid crystal display device in one field. Therefore, the liquid crystal display device is required to have high-speed response characteristics.
Accordingly, as the liquid crystal display device used in the field sequential liquid crystal display apparatus, the use of a liquid crystal display device using a ferroelectric liquid crystal capable of high-speed response, or a liquid crystal display device having a liquid crystal layer in which liquid crystal molecules are bent, has been proposed.
Unfortunately, in the liquid crystal display device using a ferroelectric liquid crystal, it is difficult to obtain uniaxial alignment in which liquid crystal molecules are evenly aligned in one direction. In the liquid crystal display device having a liquid crystal layer in which liquid crystal molecules are bent, it is difficult to obtain a liquid crystal layer in which liquid crystal molecules are stably, evenly aligned. In either case, no liquid crystal display device having stable operating characteristics and high-speed response characteristics can be obtained.
Also, the field sequential liquid crystal display apparatus always displays a color image by sequentially writing unit-color image data into the display elements of the liquid crystal display device, and sequentially turning on a plurality of light-emitting elements of the illuminating unit in accordance with this data write. This increases the number of times of data write for causing the liquid crystal display device to display one image. Since this raises the field frequency and the frequency of each signal, the power consumption also increases.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a field sequential liquid crystal display apparatus using a liquid crystal display device having stable operating characteristics and high-speed response characteristics.
To achieve the above object, the present invention is achieved by the use of a liquid crystal display device having a liquid crystal layer which is sandwiched, with the liquid crystal molecules being aligned in one direction, between a pair of substrates having electrodes formed on them, and in which the tilt angle the liquid crystal molecules make with the substrates changes in accordance with an electric field applied between the electrodes, or by the use of a homogeneous type liquid crystal display device in which liquid crystal molecules are aligned in one direction.
It is another object of the present invention to provide a field sequential liquid crystal display apparatus capable of transmission display using a illuminating light beam from an illuminating unit of the display apparatus, and reflection display using external light from the external environment of a display device, and to provide a field sequential liquid crystal display apparatus which reduces the power consumption. This object can be achieved by placing a reflecting member on the side of a liquid crystal layer of the liquid crystal display device away from the side opposite to an observer, and using a controller capable of freely turning on and off the illuminating unit.
To achieve the above objects, a liquid crystal display apparatus according to a first aspect of the present invention comprises a liquid crystal display device including a pair of opposing substrates, electrodes formed to oppose each other on opposing inner surfaces of the pair of substrates, and a liquid crystal layer sandwiched between the pair of substrates with liquid crystal molecules being aligned in one direction, of which the tilt angle to the inner surfaces of the substrates changes in accordance with an electric field applied between the electrodes, in which a display element for controlling transmission of a light beam is formed by at least one region in which the electrodes oppose each other; an illuminating unit is placed on one side of the liquid crystal display device to display an arbitrary color by mixing a plurality of unit colors, the illuminating unit selectively emitting light beams having the plurality of unit colors and irradiating the liquid crystal display device with the light beams having the plurality of unit colors; and a controller sequentially supplies to the liquid crystal display device a plurality of display signals corresponding to the light beams having the plurality of unit colors emitted by the illuminating unit, in each period during which one unit color of the light beams having the plurality of unit colors is displayed, and which causes the illuminating unit to selectively emit a light beam having a unit color corresponding to the display signal in each period.
In this invention according to the first aspect, the liquid crystal display device of the field sequential liquid crystal display apparatus has the liquid crystal layer which is sandwiched with the liquid crystal molecules being aligned in one direction, and in which the tilt angle the liquid crystal molecules make with the substrates changes in accordance with an electric field applied between the electrodes. Since the structure of the liquid crystal layer is simple, the liquid crystal molecules are evenly and stably aligned. Consequently, stable operating characteristi
Aoki Hisashi
Mizutani Yasushi
Wakai Haruo
Yamauchi Shingo
Awad Amr
Casio Computer Co. Ltd.
Frishauf Holtz Goodman & Chick P.C.
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