Patent Application
20170263893
The present disclosure relates to a method of manufacturing a light extraction substrate for an organic light-emitting diode (OLED) device. More particularly, the present disclosure relates to a method of manufacturing a light extraction substrate for an OLED device that can improve the light extraction efficiency of the OLED device, significantly simplify the manufacturing process of the OLED device, and significantly reduce the manufacturing costs and manufacturing time of the OLED device.
Generally, an organic light-emitting diode (OLED) is comprised of an anode, a light-emitting layer, and a cathode. Here, when a voltage is induced between the anode and the cathode, holes from the anode are injected into a hole injection layer, from which holes migrate to an emission layer through a hole transport layer, while electrons from the cathode are injected into an electron injection layer, from which electrons migrate to the emission layer through an electron transport layer. The electrons and the holes that have migrated into the emission layer recombine with each other, thereby generating excitons. When these excitons transit from an excited state to a grounded state, light is emitted.
Organic light-emitting diode display devices including such OLEDs are divided into passive matrix organic light-emitting diode display devices and active matrix organic light-emitting diode display devices according to the driving modes of N×M number of pixels arranged in a matrix pattern utilized thereby.
In the case of active matrix organic light-emitting diode display devices, a pixel electrode defining an emission region and a unit pixel driving circuit for applying an electric current or a voltage to the pixel electrode are disposed in a unit pixel area. The unit pixel driving circuit includes at least two thin-film transistors (TFTs) and a single capacitor to enable the supply of a certain amount of electric current, irrespective of the number of pixels, thereby obtaining a reliable level of luminance. Such active matrix organic light-emitting diode display devices may be adaptable to high resolution and large displays, due to having reduced power consumption.
However, in the case of a planar OLED-based lighting device, at least half of light generated by the light-emitting layer is lost by reflection or absorption inside of or at the boundaries of the diode due to the thin film multilayer structure, instead of exiting forwards. Thus, an additional amount of current must be applied to obtain a desired level of luminance. In this case, however, power consumption may increase, thereby reducing the lifetime of the diode.
To overcome this problem, a technology for forwardly extracting light that would otherwise be lost in the interior or boundaries of an OLED is required. This technology is referred to as light extraction technology. A problem solving scheme based on the light extraction technology is intended to remove any factor that prevents light from traveling forwards, so that that the light is lost inside of or at the boundaries of the OLED, or to disturb the travel of light. In this regard, external light extraction methods and internal light extraction methods are typically used. External light extraction methods are devised to reduce total internal reflection at the boundary between a substrate and the surrounding air by forming textures in the surface of the outermost portion of the substrate or coating the outermost portion with a layer having a different refractive index from the substrate. Internal light extraction methods are devised to reduce a waveguide effect in which light travels along the boundary between layers having different refractive indices and thicknesses instead of traveling forwards through the boundary, by forming surface textures between a substrate and a transparent electrode or forming a coating layer having a different refractive index from the substrate between a substrate and a transparent electrode.
However, conventional light extraction technology or light extraction layer forming methods as described above require the use of complicated processing methods, such as a photolithography, and expensive equipment, which are problematic. Even in the case in which surface textures are formed between the substrate and the transparent electrode, a planarization layer must be additionally formed between the surface textures and the transparent electrode. This consequently results in complicated manufacturing processing, increased manufacturing costs, and increased manufacturing time, which are problematic.
United States Patent Application Publication No. 2012-0049151 (Mar. 1, 2012)
Accordingly, the present disclosure has been made in consideration of the above problems occurring in the related art, and the present disclosure proposes a method of manufacturing a light extraction substrate for an organic light-emitting diode (OLED) device that can improve the light extraction efficiency of the OLED device, significantly simplify the manufacturing process of the OLED device, and significantly reduce the manufacturing costs and manufacturing time of the OLED device.
According to the present disclosure, a method of manufacturing a light extraction substrate for an organic light-emitting diode (OLED) device may include: forming an ion implantation layer within a base to be disposed on a transparent electrode of an OLED by implanting ions into the base through a surface of the base; and forming a void layer including a number of voids within the base by applying heat energy to the ion implantation layer, a refractive index of the number of voids being different from a refractive index of the base, wherein the number of voids are induced by gasification of the ions.
The base may be a transparent substrate formed from a thermally or ultraviolet curable polymeric material, soda-lime glass, or aluminosilicate glass.
In addition, the ions used in the step of forming the ion implantation layer may be formed from at least one selected from a candidate group consisting of H2, Ar, He, and N2.
According to the present disclosure, a method of manufacturing a light extraction substrate for an (OLED) device may include: forming a metal oxide layer on a base, the metal oxide layer being formed from a metal oxide having a first refractive index; forming an ion implantation layer within the metal oxide layer by implanting ions into the metal oxide layer through a surface of the metal oxide layer; and forming a void layer including a number of voids within the metal oxide layer by applying heat energy to the ion implantation layer, the number of voids having a second refractive index, wherein the number of voids are induced by gasification of the ions.
The metal oxide used in the step of forming the metal oxide layer may be one selected from the group consisting of ZnO, Al2O3, TiO2, SnO2, ZrO2, and SiO2.
The ions used in the step of forming the ion implantation layer may be formed from at least one selected from a candidate group consisting of H2, Ar, He, and N2.
An exposed surface of the metal oxide layer may be to be in contact with a transparent electrode of an organic light-emitting diode.
As set forth above, according to the present disclosure, it is possible to induce the formation of voids within a substrate acting as a light extraction layer of an OLED device by implanting ions into the substrate and then applying heat energy to the implanted ions. Since a single substrate can be imparted with two refractive indices, the light extraction efficiency of an OLED device can be improved.
In addition, according to the present disclosure, it is possible to significantly simplify a manufacturing process and significantly reduce manufacturing costs and manufacturing time by forming a number of voids within a substrate by a simple process including ion implantation and heat treatment.
Hereinafter, a method of manufacturing a light extraction substrate for an organic light-emitting diode (OLED) device according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
In the following description, detailed descriptions of known functions and components incorporated herein will be omitted in the case that the subject matter of the present disclosure may be rendered unclear by the inclusion thereof.
As illustrated in
The method of manufacturing a light extraction substrate for an OLED device according to the one embodiment of the present disclosure includes an ion implantation step and a heat treatment step. mom As illustrated in
In the ion implantation step, ions are implanted into the base 110 through one surface of the base 110. Specifically, in the ion implantation step, the ions are implanted to a predetermined depth from the surface of the base 110. When the ions are implanted in this manner, the implanted ions are densely distributed at the predetermined depth within the base 110, thereby forming an ion implantation layer 120, i.e. a layer having a thickness of several hundred nanometers to several micrometers, within the base 110.
In this ion implantation step, ions to be implanted into the base 110 to form the ion implantation layer 120 may be formed using at least one selected from the candidate group consisting of H2, Ar, He, and N2. Here, the ion implantation may be performed using an ion implantation apparatus (not shown).
Subsequently, the heat treatment step is a step of applying heat energy to the ion implantation layer 120. The heat treatment step is also a step of forming a void layer comprised of a number of voids within the base 110, the refractive index of the voids being different from the refractive index of the base 110.
In the heat treatment step, thermal annealing is performed on the base 110 to apply heat energy to the ion implantation layer 120. When the base 110 having the ion implantation layer 120 therewithin is subjected to thermal annealing, heat energy is transferred to the ion implantation layer 120, thereby significantly increasing the mobility of ions of the ion implantation layer 120. At this time, the ions having the increased mobility gather with the adjacent ions, thereby being converted into gas. As illustrated in
As illustrated in
Since the method of manufacturing the light extraction substrate for an OLED device according to the one embodiment of the present disclosure provides a simple process consisting of the ion implantation step and the heat treatment step as described above, the manufacturing process of the light extraction substrate 100 can be significantly simplified and the manufacturing costs and manufacturing time of the light extraction substrate 100 can be significantly reduced.
Since the OLED 10 has the above-described structure, when a forward voltage is induced between the anode 11 and the cathode 13, electrons migrate from the cathode 13 to the emission layer through the electron injection layer and the electron transport layer, while holes migrate from the anode 11 to the emission layer through the hole injection layer and the hole transport layer. The electrons and the holes that have migrated into the emission layer recombine with each other, thereby generating excitons. These excitons transit from an excited state to a ground state, thereby emitting light. The brightness of the emitted light is proportional to the amount of current that flows between the anode 11 and the cathode 13.
When the light extraction substrate 100 manufactured according to the one embodiment of the present disclosure is provided or disposed on the anode 11, or the transparent electrode, of the above-described OLED, the difference in refractive indices between the base 110 and the number of voids 130 can improve the extraction efficiency of light generated by the organic light-emitting layer 12. The number of voids 130 can act to scatter light emitted from the organic light-emitting layer 12 through a variety of paths. This can consequently further improve the light extraction efficiency of the OLED device, so that the OLED device can be driven at a low current level. It is thereby possible to reduce the power consumption of a lighting system or a display device using the OLED 10 as a light source while improving the luminance thereof.
Hereinafter, a method of manufacturing a light extraction substrate for an OLED device according to another embodiment of the present disclosure will be described in detail with reference to
The method of manufacturing the light extraction substrate according to the another embodiment of the present disclosure includes a metal oxide layer forming step, an ion implantation step, and a heat treatment step.
First, as illustrated in
In the metal oxide layer forming step, the metal oxide layer 220 may be formed from one metal oxide selected from among ZnO, Al2O3, TiO2, SnO2, ZrO2, and SiO2.
As illustrated in
The heat treatment step according to the another embodiment of the present disclosure is substantially the same process as the heat treatment step according to the one embodiment of the present disclosure. Thus, the mobility of ions of the ion implantation layer 230 is significantly increased by heat energy, so that the ions form the number of voids 240 within the metal oxide layer 220 in the same mechanism as ions according to the one embodiment of the present disclosure. Here, the number of voids 130 formed may have random sizes and shapes.
As illustrated in
As illustrated in
As set forth above, the method of manufacturing a light extraction substrate for an OLED device manufactured according to the another embodiment of the present disclosure not only can improve the light extraction efficiency of the OLED device, but can also simplify the manufacturing process of the light extraction substrate 200 and significantly reduce the manufacturing costs and manufacturing time of the light extraction substrate 200, using the simple processes of ion implantation and heat treatment, like the one embodiment of the present disclosure.
The foregoing descriptions of specific exemplary embodiments of the present disclosure have been presented with respect to the drawings. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed, and obviously many modifications and variations are possible for a person having ordinary skill in the art in light of the above teachings.
It is intended therefore that the scope of the present disclosure not be limited to the foregoing embodiments, but be defined by the Claims appended hereto and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2014-0118893 | Sep 2014 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2015/009272 | 9/3/2015 | WO | 00 |
