Patent Application
20180175321
The present disclosure relates to transparent organic light emitting diodes (OLEDs), and, more particularly, to a transparent OLED and a method for manufacturing the same.
With the increasing demands for electronic products and the improvements in lighting application technology, organic light-emitting diodes (OLEDs) technology is developing rapidly. Display devices or lighting fixtures using OLEDs, having the advantages of self-luminescent, fast response, high color saturation etc., coupled with simple processes and lower costs, have gradually become the mainstream on the market.
Among these, transparent OLEDs are able to achieve transparent display without the need for backlights. The light emitting principle behind this is a glass substrate, used as the base, being sequentially provided with a transparent electrode (ITO; anode), an organic light emitting layer and a metal electrode (cathode) thereon; when power is supplied to the transparent electrode and the metal electrode at an appropriate voltage, holes from the anode and electrons from the cathode are combined in the organic light emitting layer to produce photons, which may produce primary colors such as red, green and blue, depending on the materials of the organic light emitting layer used. Therefore, this type of transparent OLED in which the light source capable of passing through the transparent electrode or the metal electrode can be applied to smart handheld devices (such as transparent mobile phones or tablets), display windows (such as jewelry display cabinets, refrigerators, department store windows), cars (such as transparent display car windows), advertising billboards and many other fields. Currently, this new type of transparent OLEDs has become a main research area driven by the large market demands in the foreseeable future.
Referring to
To this end, there is a need in the industry for an improvement on the low transmittance of the conventional transparent OLED due to the metal cathode.
The present disclosure provides a transparent organic light emitting diode (OLED), in which a metal cathode is coated only on the surface of an organic light emitting layer on transparent anodes but not the remaining areas to reduce the coating area of the metal cathode and improve the light transmittance.
In order to achieve the above and other objectives, the present disclosure provides a transparent organic light emitting diode (OLED), which may include: a transparent substrate; transparent anodes arranged at an interval on the transparent substrate and bridged by an insulating layer; at least an isolation pillar provided above the insulating layer; an organic light emitting layer coated on the surfaces of the transparent anodes and the isolation pillars; and a metal cathode coated on the surface of the organic light emitting layer on the transparent anodes. When light passes through the transparent OLED, only the areas where the metal cathode is coated will affect the light transmittance, and the rest of the areas not coated with the metal cathode may maintain a better transmittance. By reducing the coating area of the metal cathode, the transparent OLED is able to increase its transmittance accordingly.
In one embodiment, the insulating layer and the isolation pillars are made of transparent or semi-transparent resins.
The present disclosure further provides a method for manufacturing a transparent OLED, which may include: providing a transparent substrate; forming transparent anodes at an interval on the transparent substrate; forming an insulating layer between the transparent anodes; disposing at least an isolation pillar above the insulating layer; forming an organic light emitting layer on the surfaces of the transparent anodes and the isolation pillars; and coating a metal cathode on the surface of the organic light emitting layer on the transparent anodes by using a mask.
The present disclosure further provides another method for manufacturing a transparent OLED, which may include: providing a transparent substrate; forming transparent anodes at an interval on the transparent substrate; forming an insulating layer between the transparent anodes; disposing at least an isolation pillar above the insulating layer; forming an organic light emitting layer on the surfaces of the transparent anodes and the isolation pillars; coating a metal cathode on the surface of the organic light emitting layer on the transparent anodes and on the surfaces of the isolation pillars; and removing the isolation pillars.
The present disclosure further provides another method for manufacturing a transparent OLED, which may include: providing a transparent substrate; forming transparent anodes at an interval on the transparent substrate; forming an insulating layer between the transparent anodes; forming an organic light emitting layer on the transparent anodes; and coating a metal cathode on the surface of the organic light emitting layer on the transparent anodes by using a mask.
The present disclosure can be more fully understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings, wherein:
The following illustrative embodiments are provided to illustrate the disclosure of the present disclosure, these and other advantages and effects can be apparently understood by those in the art after reading the disclosure of this specification. The present disclosure can also be performed or applied by other different embodiments. The details of the specification may be on the basis of different points and applications, and numerous modifications and variations can be devised without departing from the spirit of the present disclosure.
Referring to
The transparent anodes (e.g., Indium Tin Oxide (ITO)) 10 are arranged at an interval on the transparent substrate and bridged by an insulating layer made of a transparent or semi-transparent resin, such as polyimide (PI) 11. Isolation pillars 110 made of transparent or semi-transparent resin are then provided above the insulating layer 11.
In the first embodiment, the insulating layer 11 and the isolation pillars 110 can be made of a transparent resin including poly methyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), or polyethylene terephthalate (PET or PETE) having a transmittance of 80% or more for visible light having wavelengths in the range from 400 nm to 800 nm, or a semi-transparent resin including polypropylene (PP) or polyamide (PA) having a transmittance between 50%-85% for visible light having wavelengths in the range from 400 nm to 800 nm.
The organic light emitting layer 20 is coated on the surfaces of the transparent anodes 10 and the isolation pillars 110.
The metal cathode 30, which can be made of a metal material, is coated on the surface of the organic light emitting layer 20 on the transparent anodes 10.
As shown in
In existing transparent OLEDs, since the isolation pillars 110 are provided between the transparent anodes 10, the isolation pillars 110 occupy a considerable amount of area of a transparent OLED. If a full-screen coating of the metal cathode is used, as is the case in the prior art, in which the surfaces of both the organic light emitting layer and the isolation pillars are coated with the metal cathode, transmittance of light passing through the areas of the transparent anodes 10 and the isolation pillars 110 will be reduced due to the presence of the metal cathode 30.
On the contrary, in the transparent OLED in accordance with the first embodiment of the present disclosure, the metal cathode 30 is only provided on the surface of the organic light emitting layer 20 on the transparent anodes 10, not on the surface of the organic light emitting layer 20 on the isolation pillars 110. Therefore, the transmittance of the transparent OLED according to the present disclosure, when compared with that of the conventional transparent OLED, is only affected where the first light source L1 is passing through the surface of the organic light emitting layer 20 on the transparent anodes 10 on which the metal cathode 30 is provided, and the second light source L2 is capable of maintaining a better transmittance. In general, the overall transmittance of the transparent OLED is greatly improved by reducing the coating area of the metal cathode 30.
Referring to
As shown in
Moreover, referring to
The transparent anodes (e.g., ITO) 10 are arranged at an interval on the transparent substrate and bridged by an insulating layer made of transparent or semi-transparent resin such as polyimide (PI) 11.
In the second embodiment, the insulating layer 11 can be made of a transparent resin including poly methyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), or polyethylene terephthalate (PET or PETE) having a transmittance of 80% or more for visible light having wavelengths in the range from 400 nm to 800 nm, or a semi-transparent resin including polypropylene (PP) or polyamide (PA) having a transmittance between 50%-85% for visible light having wavelengths in the range from 400 nm to 800 nm.
The organic light emitting layer 20 is coated on the surfaces of the transparent anodes 10.
The metal cathode 30, which can be made of a metal material, is coated on the surface of the organic light emitting layer 20 on the transparent anodes 10.
As shown in
In the transparent OLED in accordance with the second embodiment of the present disclosure, the metal cathode 30 is only provided on the surface of the organic light emitting layer 20 on the transparent anodes 10. Therefore, the transmittance of the transparent OLED according to the present disclosure, when compared with that of the conventional transparent OLED, is only affected where the first light source L1 is passing through the surface of the organic light emitting layer 20 on the transparent anodes 10 on which the metal cathode 30 is provided, and the second light source L2 is capable of maintaining a better transmittance.
In summary, the difference between the second embodiment and the first embodiment is that the second embodiment lacks the isolation pillars 110. However, in the first and the second embodiments, the same technical feature exists, in which the metal cathode 30 in only coated on the surface of the organic light emitting layer 20 on the transparent anodes 10, but not on the remaining areas. By reducing the coating area of the metal cathode 30, the transmittance of light can be increased.
Referring to
In the above method, the isolation pillars are first disposed and then removed. Therefore, the finished transparent OLED will not have any isolation pillars. In an alternative, after step S83, i.e., after an insulating layer being formed between the transparent anodes, the next step for forming the isolation pillars is skipped, and, instead, an organic light emitting layer is formed on the transparent anodes as shown in step S88. Finally, a metal cathode is formed on the surface of the organic light emitting layer on the transparent anodes using a mask to complete the manufacturing of the transparent OLED, as shown in step S89.
The transparent OLED formed in the above alternative has no isolation pillars. In summary, the metal cathode can be formed on only the surface of the organic light emitting layer on the transparent anodes through the use of mask or by forming and subsequently removing the isolation pillars. As shown in
The foregoing descriptions of the detailed embodiments are only illustrated to disclose the features and functions of the present disclosure and not restrictive of the scope of the present disclosure. It should be understood to those in the art that all modifications and variations according to the spirit and principle in the disclosure of the present disclosure should fall within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 105219225 | Dec 2016 | TW | national |
