Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Patent
1997-10-21
2000-08-01
Saras, Steven J.
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
345 75, 345211, G09G 322
Patent
active
060973595
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a field emission element under use of cold-cathode and electric field, and more particularly to a cell driving device of a field emission display (hereinafter, called it "FED") which is capable of providing a gray level over a predetermined scale to a pixel by regulating the amount of current supplied to a cathode.
BACKGROUND ART
A cathode-ray tube (CRT) is a vacuum tube of a particular structure, which is useful to a various of electronic apparatus called a general display such as a television receiver, an oscilloscope, and a computer monitor. The original function of the CRT is to convert information included in an electric input signal into optical beam energy, and then to visibly display the electric input signal.
In the CRT, the electrons emitted from the thermionic cathode are focused and accelerated through focusing and accelerating electrodes. Also, the electronic beam deflects from a deflection coil on axes of the vertical or horizontal direction and then impacts upon a fluorescent film coated on a face plate of the cathode-ray tube to thereby display a predetermined picture.
The input signal having information to be displayed is provided to a plurality of grids and cathodes. However, since beam current called gamma characteristic is a non-linear function of control voltage, the more complicated compensating circuit should be disposed between the input signal and the plurality of grids to provide linear display intensity.
During the last several years, the trend is moving from a plate display toward development of a non-thermionic cathode, i.e., a field emission array.
The use of the field emission cathode array, instead of the conventional thermionic cathode in the CRT provides some merits. In particular, the use of the field emission cathode enables current density to be very high and lengthens the life of the CRT by eliminating a heat element.
However, according to the field emission cathode, the emission amount of electron for the input signal can be more non-linearly changed than in the thermionic cathode, so that there should be a more complicated compensating circuit in the field emission cathode.
In order to solve such a problem, here are two cell driving devices of the FED, one of which is based on a passive matrix addressing method disclosed in U.S. Pat. No. 5,103,145 and proposed by Doran. The other is based on an active matrix addressing method disclosed in U.S. Pat. No. 5,306,862 and proposed by Parker.
According to the U.S. Pat. No. 5,103,145, the cell driving device of the FED in accordance with the passive matrix addressing method converts an input signal into a digital signal and increases linearly the emission amount of the electron by increasing the number of cathodes driven depend upon a logic value of the digital signal. In this case, more gray levels are implemented by the number of cathodes. Thus, it is difficult to embody the gray levels over a predetermined limitation because there could be a limited number of cathodes to be installed in an occupying area of the cell.
In addition, the cell driving device of the FED in accordance with the passive matrix addressing method employs a voltage driving method which permits the electron to be emitted by voltage differential between the cathode and a gate. However, in this case, the current for voltage is non-linearly changed. Therefore, a problem may arise in that it is difficult to accurately regulate the amount of electrons emitted, from the cathode,
In contrast, the cell driving device of the FED according to the active matrix addressing method disclosed in the U.S. Pat. No. 5,300,862 is intended to drive pixels of high electric field under use of both an integrated circuit consisting of CMOS or NMOS transistors and an input signal at a low voltage. In addition, the cell driving device of the FED according to the active matrix addressing method uses a MOS transistor at a high voltage as a scan and a data switch in order to drive the cathode arranged in 9 row lines and 8 colum
REFERENCES:
patent: 5103145 (1992-04-01), Doran
patent: 5157309 (1992-10-01), Parker et al.
patent: 5210472 (1993-05-01), Casper et al.
patent: 5300862 (1994-04-01), Parker et al.
patent: 5457356 (1995-10-01), Parodos
patent: 5644195 (1997-07-01), Browning
patent: 5786795 (1998-07-01), Kishino et al.
patent: 5847515 (1998-12-01), Lee et al.
Her Gun Mu
Hyun Chang Ho
Kwon Oh Kyong
Na Young Sun
Alphonse Fritz
Orion Electric Co. Ltd.
Saras Steven J.
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