Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Light emitting device and electric device using the same

a technology of light emitting devices and electric devices, applied in static indicating devices, organic semiconductor devices, instruments, etc., can solve problems such as hard to generate noise, deterioration of luminance, and major problems of reliability of devices, and achieve the effect of improving conductivity

Inactive Publication Date: 2005-05-19
SEMICON ENERGY LAB CO LTD
View PDF19 Cites 24 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0020] Then, the object of the invention is to improve the alternating current drive method of the organic light emitting element capable of relaxing the luminance deterioration and preventing short circuits in the initial driving period more than before and to prevent the device from being destroyed by dielectric breakdown in a long term. In addition, the object is to provide a light emitting device with reduced luminance deterioration and excellent yields by combining the alternating current drive means and the organic light emitting element.
[0021] Moreover, the object is to provide an electric device excellent in long time reliability more than before by manufacturing the electric device with the use of the light emitting device.
[0032] Besides, the invention is characterized in that a layer containing a conductive polymer compound is disposed between the organic compound layer and the first electrode, or between the organic compound layer and the second electrode. Particularly, in view of improving the conductivity, the layer containing the conductive polymer compound preferably further has an acceptor or a donor for the conductive polymer. Also in this case, the conductivity of the layer containing the conductive polymer compound is preferably 10−10 S / cm or greater.

Problems solved by technology

Further, since the organic light emitting device is a carrier-injecting type light emitting device, it can be driven by DC voltage, and is hard to generate noise.
However, the reliability of the device can be a major problem of such a light emitting device.
With respect to the reliability, the luminance being deteriorated over time is a particularly conspicuous problem, and a considerable improvement is needed.
However, when the luminance is being reduced over time, the current efficiency (the ratio of the luminance to the current density) itself is being reduced compared with the initial driving period.
In other words, since the leakage current not contributing to light emission is increased, it is likely to destroy the element by dielectric breakdown with the voltage smaller than Vb in the long term.
However, in the long view, the possibility of dielectric breakdown emerges even in the reverse bias voltage Vr where the element was not supposed to be destroyed by dielectric breakdown in the initial driving period.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Light emitting device and electric device using the same
  • Light emitting device and electric device using the same
  • Light emitting device and electric device using the same

Examples

Experimental program
Comparison scheme
Effect test

embodiments

Embodiment 1

[0073] In the embodiment, in a organic light emitting element in which a polymer compound producing light emission was applied as an organic compound layer and a layer including a conductive polymer compound was disposed between an anode and the organic compound layer, luminance deterioration was measured in the constant voltage alternating current drive (the drive in which both the forward bias and the reverse bias are set to a fixed voltage).

[0074]FIG. 5 shows a device structure. First, an aqueous solution of 1.3 wt % of PEDOT / PSS was applied to a glass substrate 501 deposited with ITO of a thickness of 110 nm as an anode 502, and the substrate was baked at a temperature of 100° C. for one hour to form a layer 503 containing a conductive polymer compound. The film thickness was formed to be about 30 nm.

[0075] Subsequently, the substrate was vacuum-baked at a temperature of 80° C. for three minutes, and a toluene solution of 0.16 g of poly(p-phenylene vinylene) deriva...

embodiment 2

[0080] In this embodiment, the same device as Embodiment 1 was fabricated, and the reliability of the device was measured as the driving conditions were slightly varied. The constant voltage alternating current drive was performed where a forward bias was 3.8 [V], a reverse bias was 1.4 [V], a duty ratio was 50%, and a frequency was 600 Hz (the initial luminance at this time was about 300 cd / cm2). The result is shown by Plot AC in FIG. 7. About 60% of the initial luminance was maintained even after about 700 hours passed.

embodiment 3

[0083] An example of a passive matrix light emitting device is shown in Embodiment 3 as an example of a light emitting device disclosed by the present invention. A top view thereof is shown in FIG. 8A, and a cross sectional diagram of FIG. 8A cut along a line P-P′ is shown in FIG. 8B. In addition, element structures of the organic light emitting element can be various, the compositions such as ones shown in Embodiments 2 and 3 may be adapted.

[0084] Reference numeral 801 denotes a substrate in FIG. 8A, and glass is used for the substrate here. A plastic material also can be used; as the plastic material, polyimide, polyamide, acrylic resin, epoxy resin, PES (polyether sulfile), PC (polycarbonate), PET (polyethylene terephthalate), or PEN (polyethylene naphthalate), which are in a plate shape, or a film shape can be used.

[0085] Reference numeral 802 denotes a scanning line (anode) made from an oxide conductive film, and an indium tin oxide (ITO) is used in Embodiment 3. Further, ref...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The purpose of the present invention is to provide a light emitting device using an organic light emitting element and allowed to be driven stably with long lifetime. In a light emitting device having an organic light emitting device provided with an organic compound layer for obtaining light emission by applying a voltage between a first electrode and a second electrode, and means for applying a forward bias for emitting light from the organic light emitting device and a reverse bias of reverse polarity to the forward bias, the maximum voltage Vf of the forward bias is higher than the maximum voltage Vr of the reverse bias in an alternating current cycle formed of the forward bias and the reverse bias. At this time, the Vr is preferably a quarter of the Vf or higher than that. Additionally, the time Tr to apply the reverse bias in the alternating current cycle is preferably equal to or longer than the time Tf to apply the forward bias.

Description

BACKGROUND OF THE INVENTION [0001] 1. Filed of the Invention [0002] The present invention relates to an organic light emitting device having an anode, a cathode, and a layer containing organic compounds in which luminescence can be obtained by applying an electronic field (hereafter referred to as organic compound layer). The present invention particularly relates to an organic light emitting element having a longer drive life than that of conventional ones, and a light emitting device using the organic light emitting element. [0003] 2. Description of the Related Art [0004] An organic light emitting element is an element which emits light when an electronic field is applied. A luminescence mechanism thereof has been said: applying a voltage to an organic compound layer interposed between electrodes, electrons injected from a cathode and positive holes injected from an anode recombine together at a center of luminescence in the organic compound layer to form excited molecules; energy...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): H05B44/00
CPCG09G3/3216G09G3/3225H05B33/0896G09G2320/043H01L2251/564G09G2310/0256H05B45/60Y02B20/30H10K71/841
Inventor SEO, SATOSHINAKASHIMA, HARUEYAMAZAKI, SHUNPEI
Owner SEMICON ENERGY LAB CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com