KR20170066935A - Integrated microlens array on glass for high output light efficiency of OLED and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an improvement of the external light efficiency of an organic electroluminescent device, and includes two electrodes (a first electrode and a second electrode) formed on a substrate on which the microlenses are integrated, including a microlens integrated on the opposite side of the substrate, , Forming between the electrodes
And an organic light emitting diode (OLED) including an organic semiconductor layer formed thereon to improve the external light emitting efficiency.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode (OLED)

The present invention relates to a structure for improving the performance of an organic electroluminescent device, specifically, for improving external light emitting efficiency. A microlens is used for improving the external luminous efficiency, and the microlens is directly integrated on the glass substrate. abandonment

The electroluminescent device is easy to manufacture and has a high advantage in terms of its luminescence and power consumption, and has been applied to point light sources and surface light sources. In particular, PDPs and LCDs have been attracting attention as next generation display information devices. In addition, the organic layer deposited between the two electrodes

When a transparent substrate bent to a thickness of nm is applied, a flexible display device can be realized.

An organic electroluminescent device is fabricated by depositing or depositing a specific organic semiconductor material between a first electrode and a second electrode formed on a transparent substrate. This process enables the production of point and surface light sources through a single process that extends on a single substrate.

Discloses the characteristics of a conventional organic electroluminescent device and its preferable application. U.S. Patent No. 6,168,282, issued to Chien on January 2, 2001, for example). In this case, an organic electroluminescent device applied for illumination has been disclosed, but it is difficult to apply the organic electroluminescent device effectively because of limited light emission in organic semiconductors. In order to achieve this, efforts have been made to improve the optical efficiency by arranging the organic light emitting diode (OLED) formed on the substrate and the microlens on the opposite side of the substrate on which the organic light emitting diode is formed by applying a conventional micromachining and semiconductor pattern forming process. This is because the process of forming the organic light emitting diode (OLED) and the process of forming the microlens are separately performed on the substrate, and the process of joining them after the two processes increases the complexity and limits the mass production. .

The present invention provides a novel method for improving the external luminous efficiency of an organic electroluminescent device.

According to the present invention, an organic electroluminescent device composed of a microlens array integrated on a substrate, and an organic light emitting diode formed on the substrate on which the microlenses are arranged corresponds to the above-described requirement of the present invention.

The present invention provides a simple process as a process for applying conventional semiconductor and micromachining techniques, and lowers the cost.

It is still another object of the present invention to provide a method that can be applied to the formation of optical lines and other structures for transmission in accordance with the present invention.

Other objects and features of the present invention will become more apparent from the following detailed description.

A microlens structure is directly formed on a glass substrate to be applied as a substrate of an organic electroluminescent device by applying a semiconductor and a micromachining process to improve the external light efficiency of the organic electroluminescent device, The organic electroluminescent device having improved external light efficiency is provided.

The structure of a basic organic electroluminescent device includes two electrodes, for example, an organic layer disposed between a first electrode for injecting holes and a second electrode for injecting electrons, that is, a hole injecting layer, a hole formed in the hole injecting layer Transport layer, a light-emitting layer formed on the hole-injecting layer, an electron-transporting layer formed on the light-emitting layer, and a buffer layer formed on the electron-transporting layer. The substrate is preferably a transparent glass substrate, and a bent substrate can be applied using a thin glass substrate. In order to improve the characteristics of the organic electroluminescent device, addition and insertion of other functional organic materials are not excluded. The light efficiency of the organic electroluminescent device varies greatly according to the characteristics of the organic semiconductor to be applied and the transmittance of the substrate. For example, when an organic semiconductor constituting a light emitting layer is applied to a fluorescent organic semiconductor, its efficiency is up to 25%, and the efficiency is even smaller considering the loss of light reflection, refraction and the like inside the organic semiconductor. Other methods of improving the internal light efficiency, such as using a special organic semiconductor layer and applying a small amount of additive for energy transfer, have been applied, but ultimately, external factors such as light reflection and refraction inside the semiconductor Many are real.

A microlens is formed on the opposite side of the substrate to improve the external light efficiency of the organic electroluminescent device including the organic light emitting diode formed on the transparent glass substrate. Micro

The formation of the lens focuses light that is refracted outward to improve the efficiency thereof, and enables application to a point light source or a surface light source. In addition, there are various techniques for forming microlenses in which light can not pass due to the size of the barrier between the pixel and the pixel. For example, after forming a mold for a lens, a transparent polymer may be used

There is a method of forming a lens structure and joining to a fabricated organic electroluminescent device, a method of forming a transparent polymer for forming a semiconductor pattern on a glass substrate into a circular shape or another model, and then thermally reformation, The process of the organic electroluminescent device is repeated.

It is complicated because it is formed by different processes, and then it is joined afterwards, which is disadvantageous in that the unit price is increased.

Also, the process of joining the lenses is complicated and has a disadvantage in that productivity is lowered in mass production.

The present invention relates to a substrate (1) for an organic electroluminescence device,

A method of forming the lens 300 is provided. That is, in order to overcome the disadvantages of the prior art described above and to achieve a device having improved external light efficiency, a microlens structure is directly formed on a glass substrate using a conventional semiconductor process and a micromachining process

do. A substrate for an organic light emitting diode is a process before forming an organic light emitting diode, and a microlens pattern is formed using a photolithography process. That is, a microlens-shaped pattern is formed on the glass substrate by using a polymer (preferably a thick photoresist) as an etching mask. Thereafter, the microlenses are formed through direct etching, and the microlenses formed are substrates for the organic light emitting diodes, which are applied to substrates on which microlenses specified by the present invention are integrated. An organic light emitting diode is then formed on the opposite side of the substrate.

A conventional etching solution (preferably a buffered-oxide-etchant) is used as the etching of the glass substrate, and the glass substrate is isotropically etched into the etching solution to form a microlens.

The size of the integrated microlens of the present invention can form a desired lens structure with a size as large as a semiconductor process and can be reduced by using a basic semiconductor process and equipment.

As another example of the present invention, it is possible to form a photonic crystal as a diffraction and filter and a transmission path on a substrate on which a microlens is formed. Conventional photonic crystals use an expensive and complicated process of E-beam lithography, which makes it impossible to apply a relatively large area and increases the unit price. For this purpose, a transparent oxide inorganic thin film (preferably SiO2, TiO2), which is mainly used for forming a photonic crystal, is formed as a single layer or a thin film on the lens of the substrate surface on which the microlenses of the present invention are integrated

Forming a first electrode, forming an organic light emitting diode including an organic semiconductor layer and a second electrode,

It is possible to form the conventional photonic crystal as described above in an easier process. The thickness of the etch mask is proportional to the thickness of the etch mask, so that the etch mask is made of a photonic crystal of a desired size using metal and polymers used in general semiconductor processing

This is possible.

The organic electroluminescent device of the present invention provides a method of directly forming a microlens structure for preventing light loss for high external light efficiency on a substrate, thereby providing an organic electroluminescent device with improved light efficiency.

According to the present invention, since the conventional semiconductor process and equipment are used, the increase of the unit price is prevented, the process time is shortened, and the simple process is enabled.

Further, according to the present invention, the microlens structure integrated on the substrate is usefully applied to form other object structures.

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Claims (6)

A first electrode layer formed on the substrate,
A hole injection layer formed on the first electrode,
A hole transport layer formed on the hole injection layer,
A light emitting layer formed on the hole transporting layer,
An electron transport layer formed on the light emitting layer,
And a second electrode layer formed on the electron transport layer
And a microlens structure integrated on an opposite surface of the substrate of the organic electroluminescent device. The organic electroluminescent device according to claim 1, wherein the size of the integrated microlens ranges from 1 to 100 [mu] m. The organic electroluminescent device according to claim 1, comprising a photonic crystal formed using a structure of microlenses integrated on the substrate. 4. The organic electroluminescent device according to claim 3, wherein the size of the photonic crystal ranges from 10 nm to 100 mu m. A first electrode layer formed on the substrate; a hole injection layer formed on the first electrode;
A hole transport layer formed on the hole injection layer,
A light emitting layer formed on the hole transporting layer,
An electron transport layer formed on the light emitting layer,
And a second electrode layer formed on the electron transport layer
On the opposite surface of the substrate of the organic electroluminescent device
And an integrated micro-lens structure. 6. The organic electroluminescent device manufacturing method according to claim 5, wherein the size of the integrated microlens ranges from 1 m to 100 m