Passive driving method for organic light emitting diodes

A light-emitting diode, passive drive technology, applied to instruments, static indicators, etc., can solve the problems of insufficient brightness and predicted value, current waste, parasitic capacitance charging, etc., and achieve the effect of shortening charging time, reducing rising time, and increasing rising rate

Inactive Publication Date: 2004-07-07
RITDISPLAY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] When an OLED pixel is turned on, if each segment is driven by a constant current circuit, because of the capacitive effect of the OLED itself, part of the current will be wasted to charge the parasitic capacitance. Moreover, it takes a long time for the voltage difference across the organic light-emitting diode to reach the potential required for driving. At the same time, because the light output of the organic light-emitting diode is proportional to the current input, the effect of parasitic capacitance will lead to insufficient brightness and predictive value.

Method used

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  • Passive driving method for organic light emitting diodes
  • Passive driving method for organic light emitting diodes
  • Passive driving method for organic light emitting diodes

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Embodiment 1

[0031]Please refer to FIG. 4, which is a schematic diagram of the passive driving circuit of the organic light emitting diode according to the first embodiment of the present invention. In FIG. 4, for the convenience of description, only a diagram of the relationship between one of the light-emitting diodes and the pre-charging circuit of the entire organic light-emitting diode array is shown. Those familiar with this technology know how to integrate into an entire organic light-emitting diode array.

[0032] As shown in FIG. 4, a pre-charging circuit 40 is electrically coupled to the anode of the organic light emitting diode 30. The anode of the organic light emitting diode 30 is connected to a fixed current source I and a voltage source V through the switch device 32. pp , And its cathode is connected to a reverse bias voltage V or ground GND through another switching device 34. When the organic light-emitting diode 30 is to be lit, the switching device 32 is turned off to allow...

Embodiment 2

[0041] Please refer to FIG. 6(A), which is a schematic diagram of a passive driving circuit of an organic light emitting diode according to a second embodiment of the present invention. In FIG. 6(A), for the convenience of description, only a diagram of the relationship between one of the light-emitting diodes and the pre-charging circuit of the entire organic light-emitting diode array is shown. Those familiar with this technology can know how to integrate an entire organic light-emitting diode In the array.

[0042] The difference between the second embodiment and the first embodiment is that the reference voltage V ref the design of. The functions and connections of the comparator 54 and the switching device 52 are the same as those of the first embodiment, and the description will not be repeated here, but only the reference voltage part will be described.

[0043] In the first embodiment, the reference voltage V ref It is adjusted and changed externally, so the reference volt...

Embodiment 3

[0050] Please refer to FIG. 7(A), which is a schematic diagram of a passive driving circuit of an organic light emitting diode according to a third embodiment of the present invention. In FIG. 7(A), for the convenience of explanation, only a diagram of the relationship between one of the light-emitting diodes and the pre-charging circuit of the entire organic light-emitting diode array is shown. Those familiar with this technology can know how to integrate an entire organic light-emitting diode In the array.

[0051] In both the first embodiment and the second embodiment, a fixed precharge voltage value is used to adjust the precharge time; that is, the precharge voltage V in FIG. 6(A) and FIG. 7(A) pp It is a fixed value. However, under this structure, the actual precharge time cannot be controlled, but is automatically controlled through a feedback mechanism. Therefore, when the uniformity of the anode voltage output is required to be very high, especially when the pulse-width-m...

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Abstract

The present invention is a passive organic LED activating method. The method comprises the steps: starting to apply a voltage to the organic LED to increase its anode potential; detecting the anode potential of the organic LED; comparing the detected anode potential with a reference voltage; performing a pre-charging process to the organic LED through its anode using a voltage source if the anode potential is lower than the reference voltage; the pre-charging process is stopped when the anode potential of the organic LED reaches the predetermined reference voltage. The reference voltage can be a fixed external voltage, or can be obtained dynamically by sampling dynamically the outputting potentials of a fixed current source using a sampling holding circuit.

Description

Technical field [0001] The present invention relates to a driving method of an organic light emitting diode, in particular to a driving method of a passive organic light emitting diode. Background technique [0002] In order to meet the diversified trend of information equipment, the demand for flat panel displays (FPD) is becoming more and more urgent, and in today’s global market trend towards lighter, thinner, shorter and power-saving, cathode ray tube (CRT) type Displays have gradually been replaced by flat-panel displays. The technologies currently used in FPD mainly include the following: plasma display, liquid crystal display, electroluminescent display, light emitting diode (LED), vacuum fluorescent display (vacuum fluorescent display), field emission display (field emission display), electrochromic display (electrochromic display) and organic light emitting diode display (organic LED display), etc. [0003] The types of organic light-emitting diode displays can be divide...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09G3/3208
Inventor 吴居凡
Owner RITDISPLAY
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