US 6,650,308 B2Granted

Organic EL display device and method for driving the same

AssigneeNEC Corporation

InventorShingo Kawashima

Life of this patent

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Abstract

Organic EL elements are arranged in a matrix pattern. A column of organic EL elements are connected by their anodes to each data line. A row of organic EL elements are connected by their cathodes to each scanning line. In a data line driving circuit, a signal current source is connected to each data line, and each signal current source is connected to a power source. In a scanning line driving circuit switches are connected to each scanning line, with one end of each switch being connected to the power source, and the other end thereof being connected to the ground. The data lines are commonly connected to a Zener diode of a voltage retaining circuit via switches. A capacitor is connected in parallel to the Zener diode. The potential retained by the Zener diode is as high a potential as possible such that it is determined to be a black level of each color.

Claims20

Dependent claims

An organic EL display device, comprising:

a plurality of organic EL elements arranged in a matrix pattern;
a plurality of scanning lines each connected to a row of the organic EL elements;
a plurality of data lines each connected to a column of the organic EL elements;
a scanning line driving circuit for successively scanning said scanning lines;
a data line driving circuit for applying a driving current to a selected data line in synchronization with the scanning operation of said scanning line driving circuit;
a Zener diode capable of retaining a voltage in a range for a black level of said organic EL elements;
a switch provided between each of said data lines and said Zener diode for either commonly connecting said data lines to said Zener diode or disconnecting said data lines from one another and from said Zener diode;
and
a control circuit for turning on all of the switches to connect all of the data lines to one another and to the Zener diode when the scanning operation by said scanning line driving circuit proceeds from one scanning line to the next scanning line.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/962,114Filed 26 Sep 2001
Priority: JP 2000-29749828 Sep 2000
Published: US 2002/0036605 A128 Mar 2002
Granted: 18 Nov 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G09G 3/3216
Organic, e.g. using organic light-emitting diodes [OLED]: using a passive matrix
G09G 2310/0251
Details of the generation of driving signals: precharge or discharge of pixel before applying new pixel voltage
G09G 2310/0256
Control of polarity reversal in general, other than for liquid crystal displays: with the purpose of reversing the voltage across a light emitting…
G09G 2320/043
Maintaining the quality of display appearance: preventing or counteracting the effects of ageing