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Method for prolonging service life of OLED light-emitting device through AC driving

A technology of AC drive and light-emitting devices, which is applied in the direction of electroluminescence light source, light source, electric light source, etc., can solve the problems of device brightness attenuation, current reduction, device temperature rise, etc., to prevent the accumulation of charges and reduce the heat generation time , The effect of extending the lighting life

Inactive Publication Date: 2016-07-20
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, under DC drive, the heat generation time of the device increases, which will cause the temperature of the device to rise. Excessive heat energy may change the stability of the organic film, the interface stress of the electron transport layer and the hole transport layer, and cause the current flow of the mixed surface. Reduced, or the interface between the electron transport layer and the metal cathode is damaged and detached, so that some interfaces are not covered by the cathode, and electrons cannot enter this part to recombine with holes to emit light, so black spots are generated, and the brightness of the device is attenuated

Method used

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  • Method for prolonging service life of OLED light-emitting device through AC driving
  • Method for prolonging service life of OLED light-emitting device through AC driving
  • Method for prolonging service life of OLED light-emitting device through AC driving

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Experimental program
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Effect test

Embodiment 1

[0022] see Figure 1-Figure 4 , the method of the present invention to prolong the service life of OLED light-emitting devices by AC driving, adopts four lighting circuits, including six green OLED devices 1, 2, 3, 4, 5, and 6 with the same device structure. The six green OLED devices 1, 2, 3, 4, 5, and 6 are respectively connected to four lighting circuits, and the four circuits are driven by different drives, namely DC drive, sine wave, square wave and pulse wave AC drive, The DC drive has only one loop, the sine wave AC drive has two loops, branch A and B, the square wave AC drive has two loops, branch C and D, and the pulse wave AC drive has only one loop.

[0023] The DC drive circuit is only connected to one device 3 , the positive pole of the DC power supply is connected to the anode of the device 3 , and the negative pole of the DC power supply is connected to the cathode of the device 3 . The AC drive adopts a sine wave, two branches A and B are respectively connecte...

Embodiment 2

[0025] The experiment uses green OLED devices packaged and stored at room temperature. DC circuits such as figure 2 As shown, using the DC output signal on the aging tester, the life aging tester can measure the aging of multiple OLED devices, and record the changes of the driving voltage and luminous brightness with time of the OLED device under the DC driving condition for a long time through the computer data acquisition system. The half-life of the OLED is calculated or measured based on the change.

[0026] Connect six OLED devices into DC and AC drive circuits. When AC is driven, the AC signal output by the signal source. Adjust the brightness of the device. After the film is turned on, let the DC drive and the AC drive start to accelerate aging at a similar brightness. Open the test interface of the aging meter, record the real-time brightness of the OLED, and obtain a comparison chart of the OLED brightness decay curves of the DC drive and the AC drive. .

[0027]...

Embodiment 3

[0031] It adopts square wave AC drive, the frequency is 50Hz, and the device connection method is as follows image 3 shown. Since the first embodiment already has the life data under DC driving, in order to avoid waste, the test will not be repeated here. When the square-wave AC drive is used, after the film is turned on, let the DC drive and the AC drive start to accelerate aging at a similar brightness, open the test interface, record the real-time brightness of the OLED, and obtain a comparison chart of the OLED brightness decay curves of the DC drive and the AC drive, like Image 6 Show.

[0032] Image 6 The three curves in the middle correspond to No. 3, 4, and 5 devices, No. 3 devices are driven by DC, and No. 4 and No. 5 devices are driven by square waves. The data analysis is the same as above, the life of device 4 is 987h, and the life of device 5 is 1081h, so the average life of the device under the square wave drive is 1034h, which is 1.37 times of the life un...

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Abstract

The invention discloses a method for prolonging service life of OLED light-emitting devices through AC driving. The method comprises the steps that: six OLED light-emitting devices are connected into a DC driving circuit and an AC driving circuit, under DC driving, the OLED light-emitting devices are always in a working state, the produced heat cannot be dissipated effectively; and under AC driving, whether it is sinusoidal wave, square wave or impulse wave with 30% positive duty ratio, the waves operate along with the alternation of periods, thus heat production time is shortened, heat dissipation is facilitated, the temperature of the devices is relatively low, organic light-emitting materials can be effectively protected, the aging of the materials can be slowed down, the service life can be prolonged, and the cost can be reduced. The AC driving circuit is more suitable in the mains supply application occasions with the frequency of 50Hz when compared with the DC driving circuit, does not need to be added with other circuits for carrying out energy conversion links such as rectification, voltage transformation and current transformation, and reduces electric energy loss.

Description

technical field [0001] The invention relates to the technical field of OLED illumination and display, in particular to a method for prolonging the service life of an OLED light-emitting device by replacing DC drive with AC drive. Background technique [0002] Organic electroluminescent devices (OLEDs) have become a research hotspot in the field of optoelectronic displays due to their excellent properties such as active light emission, wide viewing angle, uniform image quality, sensitive response, easy colorization, high brightness, rich colors, and easy fabrication. Moreover, organic electroluminescent devices not only have great potential in the field of display, but also have great room for development in solid-state lighting. However, we still lack a deep understanding of the factors that affect its stability and the aging mechanism. Relevant studies have shown that the stability of OLED is related to many factors, such as device structure, organic materials, electrode m...

Claims

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Application Information

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IPC IPC(8): H05B33/08H05B44/00
CPCH05B45/60Y02B20/30
Inventor 朱文清翟光胜俞静婷肖腾钱冰洁柯根水陶媛
Owner SHANGHAI UNIV
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