Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2002-02-21
2004-09-21
Tran, Henry N. (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S212000, C345S690000, C345S691000, C315S169300
Reexamination Certificate
active
06795045
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a driving circuit for a flat panel display device and particularly, to a driving circuit for a flat panel display device which compensates luminosity deviation according to a panel characteristic an organic electroluminescent display device.
2. Description of the Background Art
FIG. 1
is a view showing a conventional driving circuit for an electroluminescent (EL) display device.
As shown in
FIG. 1
, the conventional driving circuit for the organic EL display device includes a current control circuit
2
for supplying constant current I
0
to an organic EL display device
1
and a switching circuit
3
for switching the constant current I
0
supplied from the current control circuit
2
to the organic EL display device
1
.
On the other hand,
FIG. 2
is a view showing a graph of a constant current I
EL
supplied to the organic electroluminescent display device and a voltage of both ends V
EL
of organic electroluminescent display device
1
according to time T. At this time, Ith and Vth designate critical values with which the organic EL display device
1
emits.
Therefore, in the conventional organic EL display device, the switch circuit
3
is turned on for the time of &Dgr;d and the constant current I
EL
is supplied from the current control circuit to the organic EL display device
1
. Accordingly, The voltage V
EL
of both ends of the organic EL display device
1
is increased and when the voltage V
EL
surpasses the critical value, the organic EL display device
1
becomes to emit light. At this time, the luminosity of the light emitted from the organic EL display device
1
is determined by the size of the electric current supplied to the organic EL display device
1
and the time for supplying the current. Namely, for generating light having a uniform luminosity, the size of the electric current supplied to the organic EL display device
1
and the time for supplying the current must be uniform. However, generally, since the light-emitting characteristic of the organic EL display device
1
is differentiated according to the panel, light having a uniform luminosity cannot be generated even if an electric current is supplied uniformly in a predetermined size of the electric current and time for supplying the current. The operation will be described with reference to FIG.
3
.
FIG. 3
is a graph showing luminosity deviation of respective organic EL display devices at the time that luminescence of the respective organic EL display device is ended.
As shown in
FIG. 3
, luminosity deviation according to the organic EL display devices is generated at the time Te that luminescence is ended. The luminosity deviation is generated by circuits dependent upon the panel and to prevent the deviation, individual driving circuits according to the characteristics of the panels must be used. However, generally, since designation of a circuit is manufacturing an integrated semiconductor chip, the manufacturing is difficult and increase the manufacturing cost. Also, in case of using the individual driving circuit, the circuit must be re-designed when the luminosity deviation is generated.
As described above, with the convention art, it was difficult that the manufacturing of the driving circuit of the organic EL display device for preventing the luminosity deviation of the organic EL display device.
Also, with the conventional art, the manufacturing cost increases in manufacturing the driving circuit of the organic EL display device for preventing the luminosity deviation of the organic EL display device.
Also, with the conventional art, the circuit must be redesigned when the luminosity deviation is generated also in case individual driving circuits are used for the organic EL display device.
SUMMARY OF THE INVENTION
Therefore, the present invention provides a driving circuit for a flat panel display device, which can compensate luminosity deviation according to panel characteristics of a flat display device.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a driving circuit for a flat panel display device including a current control circuit for supplying electric current to a panel of a flat display device, a luminescence time detecting circuit for detecting luminescence time of the flat display device and a digital signal processing circuit for controlling the current control circuit on the basis of the luminescence time.
The foregoing and other, features, aspects and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5656892 (1997-08-01), Zimlich et al.
patent: 5719589 (1998-02-01), Norman et al.
patent: 5923309 (1999-07-01), Ishizuka et al.
patent: 6061041 (2000-05-01), Yoshida
patent: 6204834 (2001-03-01), Baker et al.
patent: 6310589 (2001-10-01), Nishigaki et al.
patent: 6465966 (2002-10-01), Konuma
patent: 6509885 (2003-01-01), Hanaki et al.
patent: 6545651 (2003-04-01), Nishigaki et al.
patent: 6646654 (2003-11-01), Takagi
patent: 2002/0000953 (2002-01-01), Masanori
Hong Kuk Tae
Jang Sung Jin
Lee Hong Degerman Kang & Schmadeka
LG Electronics Inc.
Tran Henry N.
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