Organic light-emitting display panel and encapsulation film each having auxiliary encapsulation layer doped with water absorbing material and manufacturing method thereof

The present invention discloses an organic light-emitting display panel, a manufacturing method thereof, and an encapsulation film thereof. In this invention, an auxiliary encapsulation layer is disposed on an outer side of an inorganic layer, and the auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer. Even if the inorganic layer cracks or peels in the bending region and the boundary region, a channel of water and oxygen generated at a cracked place or a peeling place is blocked by the auxiliary encapsulation layer, thereby ensuring an ability of the encapsulation film to block water and oxygen into an organic light-emitting device.

FIELD OF INVENTION

The present invention is related to the field of organic light-emitting diode (OLED) technology, and specifically to an organic light-emitting display panel, a manufacturing method thereof, and an encapsulation film thereof.

BACKGROUND OF INVENTION

Organic light-emitting display panels have the advantages of low cost, wide viewing angles, high contrast, and flexibility, and has achieved remarkable results in small size products and large size products. It is constantly encroaching on the market share of the liquid crystal displays (LCDs).

An organic light-emitting device is an important portion of the organic light-emitting display panel, but water and oxygen have a great influence on its lifetime. First, water and oxygen easily react with the conductive material of the cathode of the organic light-emitting device. Second, water and oxygen easily react with the hole transport layer and the electron transport layer of the organic light-emitting device, thereby causing the organic light-emitting device to fail. In order to solve these problems, the organic light-emitting display panel of the prior art encapsulates the organic light-emitting device using a thin film encapsulation (TFE) method. The encapsulation film used in the TFE method includes laminated an inorganic layer and an organic layer to prevent the organic light-emitting device from the intrusion of water and oxygen.

However, the encapsulation film used in the current TFE method still has insufficient blocking properties against water and oxygen, especially when it covers a laminated structure or a step, the inorganic layer is easy to crack or peel in the bending region and the boundary region, thereby forming a channel of water and oxygen. Water molecules and oxygen molecules intrude from the channel of water and oxygen generated by the crack of the inorganic layer. Because the organic layer has no ability to block water and oxygen, water molecules and oxygen molecules will quickly pass through the organic layer and then continue to move at the interface of the organic layer and inorganic layer. Water molecules and oxygen molecules keep intruding inward through the channel of water and oxygen generated by the next inorganic layer crack until it intrudes the organic light-emitting device. It can be seen that the crack of the inorganic layer can seriously affect the ability of the encapsulation film to block water molecules and oxygen molecules.

SUMMARY OF INVENTION

When the inorganic layer of the prior art cracks or peels, it will cause a problem that the ability of the encapsulation film to block water and oxygen into the organic light-emitting device is insufficient.

The present invention provides an organic light-emitting display panel including an organic light-emitting device, an inorganic layer, and an auxiliary encapsulation layer encapsulating the organic light-emitting device. The auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer.

The present invention further provides an encapsulation film comprising an inorganic layer, and an auxiliary encapsulation layer. The auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer.

The present invention further provides a manufacturing method of an organic light-emitting display panel, comprising the steps of:

providing a substrate;

forming an organic light-emitting device and an inorganic layer encapsulating the organic light-emitting device on the substrate; and

forming an auxiliary encapsulation layer on an outer surface of the inorganic layer, and the auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer.

In the present invention, the auxiliary encapsulation layer is disposed on the outer side of the inorganic layer, and the auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer. Even if the inorganic layer cracks or peels in the bending region and the boundary region, the channel of water and oxygen generated at the cracked place or the peeling place is blocked by the auxiliary encapsulation layer, thereby ensuring the ability of the encapsulation film to block water and oxygen into the organic light-emitting device.

DETAILED DESCRIPTION

In the present invention, the auxiliary encapsulation layer is disposed on the outer side of the inorganic layer, and the auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer. Even if the inorganic layer cracks or peels in the bending region and the boundary region, the channel of water and oxygen generated at the cracked place or the peeling place is blocked by the auxiliary encapsulation layer, thereby ensuring the ability of the encapsulation film to block water and oxygen into the organic light-emitting device.

Embodiments of the present invention are described detailly below. Examples of the embodiments are shown in the drawings, and units of the same or similar functions are using the same or similar numeral to represent. Embodiments reference to the appended drawings are used to describe and understand the present invention, not to limit the present invention.

In the description of the present invention, it is to be understood that the terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “up,” “down,” “front,” “back,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inside,” “outside,” and the like, indicate orientations or positional relationships, and are based on the orientations or positional relationships shown in the drawings, therefore may not be construed as limits to the present invention.

FIG. 1is a structural diagram of an encapsulation film according to an embodiment of the present invention. Refer toFIG. 1, the encapsulation film100includes a main encapsulation layer110and an auxiliary encapsulation layer120.

When the encapsulation film100covers a protruding structure such as a laminated structure or a step, the top surface of a region of the protruding structure covered by the main encapsulation layer110and the top surface of the other region have a height difference. The top surfaces of the two regions are not aligned. As shown inFIG. 1, it will exist a bending region110aindicated by a cracked line in the figure due to the height difference caused by the covering of the main encapsulation layer110. The main encapsulation layer110in the bending region110ais deformed and easily to crack. In addition, a boundary region110bof the main encapsulation layer110indicated by a cracked line in the figure, which is an interface between the main encapsulation layer110and a substrate200carrying the protruding structure, is easily to peel.

The auxiliary encapsulation layer120covers an outer surface of the main encapsulation layer110, and it at least covers the bending region110aand the boundary region110b. In an embodiment, the auxiliary encapsulation layer120not only covers the bending region110aand the boundary region110b, but also extends outwardly and conforms to a part of the substrate200to achieve coverage of a larger area.

The auxiliary encapsulation layer120is disposed on the bending region110aand the boundary region110bof the main encapsulation layer110which are most likely to crack or peel in encapsulation film100. Even if the main encapsulation layer110cracks or peels in these two regions, the auxiliary encapsulation layer120blocks the channel of water and oxygen generated at the cracked place or the peeling place. In this way, it is ensured that the encapsulation film100still has a strong ability of an encapsulation device to block water and oxygen, which is beneficial to ensure the normal use of the encapsulation device.

In detail, material of the main encapsulation layer110can be an inorganic material selected from the group consisting of silicon nitride, silicon oxynitride, silicon oxide, and aluminum oxide. The existence of the bending region110aallows the main encapsulation layer110to cover the device it protects, and the covered device can have an uneven surface such as a protruded platform structure. In this case, the bending region110acovers a portion having a flat surface of the protected device, and the bending region110acovers the protruded platform structure, thereby realizing the protected device has an adaptive fit and coverage protected by the main encapsulation layer110.

The auxiliary encapsulation layer120can be made of a material having a high step coverage and a good density of film formation such as inorganic material including but not limited to one or more of aluminum oxide, zirconium oxide, and titanium oxide. In an embodiment, the auxiliary encapsulation layer120is made of aluminum oxide, and the auxiliary encapsulation layer120can be formed by an atomic layer deposition (ALD) process. According to the film forming characteristics of various materials, the specific embodiment can also adopt any physical film forming process such as physical vapor deposition (PVD), pulsed laser deposition (PLD), and magnetron sputtering to produce the auxiliary encapsulation layer120. A thickness of the auxiliary encapsulation layer120can be smaller than a thickness of the main encapsulation layer110, and a step coverage of the main package layer110can be smaller than a step coverage of the auxiliary encapsulation layer120.

The step coverage is the cover effect of the encapsulation layer on the structure with a height difference. For example, for the above structure having a height difference, the encapsulation layer covers a upper portion and a lower portion, and the encapsulation layer (for example, the main encapsulation layer110) generates a bending region at an interface between the upper portion and the lower portion. If there does not happens fracture in the bending region and does not forms a complete coverage, the step coverage of the encapsulation layer and material constituting the encapsulation layer is considered to be low; if there is no fracture, the step coverage of the encapsulation layer and material constituting the encapsulation layer is considered to be high.

The auxiliary encapsulation layer120can cover one side of the main encapsulation layer110and is not limited to the outer surface shown inFIG. 1. The present invention can cover the auxiliary encapsulation layer120on an inner surface or both side surfaces of the main encapsulation layer110according to actual applications or requirements.

Depending on different features of the main encapsulation layer110and the auxiliary encapsulation layer120of the encapsulation film100, it can form different features of encapsulated surfaces. The main encapsulation layer110covers entire coverage region, and the auxiliary encapsulation layer120reinforces or fetches up those regions with poor coverage (the bending region110awhich is easily to crack, and the boundary region110bwhich is easily to peel). When the main encapsulation layer110cracks and peel, the auxiliary encapsulation layer120let the encapsulation film100keep a complete film layer to block water molecules and oxygen molecules. Even if the main encapsulation layer110does not crack and peel, the auxiliary encapsulation layer120can reinforce regions on the main encapsulation layer110that could crack or peel, and provide a higher ability of film layer to block water and oxygen on the protected device side. For example, for the auxiliary encapsulation layer120made of aluminum oxide, the ability to block water and oxygen may be between 10−4-10−6g/cm2/day, and the ability to block water and oxygen is very well, and it is ideal for encapsulating the protected device.

The encapsulation film100above can be used in the encapsulation structure of the organic light-emitting display panel to protect components, including the organic light-emitting device. The following is an example of encapsulating an organic light-emitting device, and is described in detail with the drawings.

FIG. 2is a partial sectional structural diagram of an organic light-emitting display panel according to an embodiment of the present invention. Refer toFIG. 2, an organic light-emitting display panel includes an encapsulation film100, a substrate200, and an organic light-emitting device300. The organic light-emitting device300is disposed on the substrate200and located in a pixel region defined by a pixel define layer. The encapsulation film100encapsulates the organic light-emitting device300on the substrate200.

The substrate200is a substrate of the organic light-emitting display panel for carrying various structural layers and electronic components of the organic light-emitting display panel. In order to adapt to a bendable feature of the organic light-emitting display panel, the substrate200can be a flexible board having the bendable feature, and its main compositions include but not limited to a polyimide (PI). Optionally, the substrate200can be covered with a buffer layer having a function of blocking water and oxygen, and main compositions thereof include but not limited to silicon nitride, silicon oxide, silicon oxynitride. In addition, the substrate200can be provided with various switching devices such as thin-film transistor (TFT) for realizing a screen display of the organic light-emitting display panel.

The organic light-emitting device300can include a control circuit layer (also called array circuit layer), an anode, a hole transport layer (HTL), an organic light-emitting layer, an electron transport layer (ETL), and a cathode sequentially disposed on the substrate200.

The encapsulation film100includes a second inorganic layer110(the aforementioned main encapsulation layer110), an auxiliary encapsulation layer120, an organic layer130, and a first inorganic layer140.

The first inorganic layer140covers the cathode of the organic light-emitting device300and the pixel define layer, and the first inorganic layer140further extends to a side of the organic light-emitting device300to encapsulate the organic light-emitting device300on the substrate200.

The organic layer130, which can be made by an ink-jet printing (IJP) process, is disposed on the first inorganic layer140.

The second inorganic layer110covers the organic layer130and further extends to a side of the organic layer130to cover the first inorganic layer140and a portion of the substrate200. The second inorganic layer110, which has a function of blocking water and oxygen, can be made of an inorganic material. Optionally, material and manufacturing process of the second inorganic layer110and the first inorganic layer140can be the same, for example, they all can be made by a chemical vapor deposition (CVD) process.

The organic light-emitting device300and the substrate200have a height difference, and a step coverage of the first inorganic layer140is poor due to a material property of an inorganic material such as silicon nitride, silicon oxide, silicon oxynitride. A thickness of the first inorganic layer140is between 0.5-1.5 μm so that the first inorganic layer140has a large probability to crack at the bending region140awhen it is formed on the organic light-emitting device300, and has a large probability to peel at the boundary region140bcontacted the substrate200. Similarly, the second inorganic layer110has a large probability to crack at the bending region110a, and has a large probability to peel at the boundary region110bcontacted the substrate200.

The auxiliary encapsulation layer120is disposed on an outer surface of the second inorganic layer110, and it at least covers the bending region110aand the boundary region110b. Optionally, refer toFIG. 3, the auxiliary encapsulation layer120surrounds the organic light-emitting device300.

A thickness of the auxiliary encapsulation layer120is between 50-100 nm, and refer toFIG. 3, a width can between 100-200 μm. It can be made of a material having a high step coverage and a good density of film formation such as inorganic material including but not limited to one or more of aluminum oxide, zirconium oxide, and titanium oxide. In a specific embodiment, the auxiliary encapsulation layer120can be formed by an atomic layer deposition process.

Refer toFIGS. 2 and 3, first, an atomic layer deposition process forms an entire surface inorganic layer covering an organic layer130. The entire surface inorganic layer not only covers a bending region110aand a boundary region110b, but also covers top of an organic light-emitting device300. Second, coating a layer of photoresist on the entire surface inorganic layer, and the photoresist completely covers the entire surface inorganic layer. Third, exposing the layer of photoresist with a mask. A light-transmitting region of the mask corresponds to directly above the organic light-emitting device300, thereby exposing the photoresist directly above the organic light-emitting device300. An exposed portion of the photoresist can be removed by development, at the same time, the inorganic layer directly above the organic light-emitting device300is exposed, and an unexposed portion of the photoresist still covers the entire surface of the inorganic layer. Fourth, etching the exposed portion of the inorganic layer to remove the inorganic layer of the exposed portion. Last, ashing and removing a remaining photoresist, and a remaining inorganic layer can be used to obtain the auxiliary encapsulation layer120.

Of course, depending on the feature of material used in an actual implementation, the auxiliary encapsulation layer120can also be formed by any film forming process such as physical vapor deposition, pulsed laser deposition, magnetron sputtering. A thickness of the auxiliary encapsulation layer120can be less than a thickness of the main encapsulation layer110, and a step coverage of the second inorganic layer110can be less than a step coverage of the auxiliary encapsulation layer120.

Depending on different features of the second inorganic layer110and the auxiliary encapsulation layer120, it can form different features of encapsulated surfaces on the organic light-emitting device300. The second inorganic layer110covers entire coverage region, and the auxiliary encapsulation layer120reinforces or fetches up those regions with poor coverage (the bending region110awhich is easily to crack and the boundary region110bwhich is easily to peel). When the second inorganic layer110cracks and peels, the auxiliary encapsulation layer120let the encapsulation film100keep a complete film layer to block water molecules and oxygen molecules. Even if the second inorganic layer110does not crack and peel, the auxiliary encapsulation layer120can reinforce regions on the second inorganic layer110that could crack or peel, and provide a higher ability of film layer to block water and oxygen on a side of the organic light-emitting device300.

Base on a feature of the auxiliary encapsulation layer120, it can also cover the auxiliary encapsulation layer120on an outer surface of the first inorganic layer140. When the auxiliary encapsulation layer120covers the bending region140aand the boundary region140bof the first inorganic layer140, the auxiliary encapsulation layer120can reinforce regions on the first inorganic layer140that could crack or peel. A channel of water and oxygen of the first inorganic layer140at the crack is blocked by the auxiliary encapsulation layer120, thereby further ensuring the ability to block water and oxygen into the organic light-emitting device300.

The auxiliary encapsulation layer120can be made of a transparent material, and it can further cover directly above the organic light-emitting device300.

Keep referring toFIG. 2, in a specific embodiment, at least one of the first inorganic layer140, the organic layer130, the second inorganic layer110, and the auxiliary encapsulation layer120can be doped with a water absorbing material. The water absorbing material can absorb water molecules which are intrude into the first inorganic layer140, the organic layer130, the second inorganic layer110, and the auxiliary encapsulation layer120. The water absorbing material provides a protection for the water molecules, increases the difficulty for the water molecules to reach the organic light-emitting device300, and further improves the ability to block the water molecules.

Material of the water absorbing material include but not limited to calcium oxide having a size scale at the nanometer level, which is nano-sized calcium oxide particles. A concentration of the water absorbing material sequentially increases along a direction from the organic light-emitting device300to a bending region110aand a boundary region110bof the second inorganic layer110. The closer to the region where could crack and peel, the higher the doping concentration of the water absorbing material.

FIG. 4is a flowchart of a manufacturing method of the organic light-emitting display panel according to one embodiment of the present invention. A manufacturing method of an organic light-emitting display panel includes the steps of:

S401: Providing a substrate.

S402: Forming an organic light-emitting device and an inorganic layer encapsulating the organic light-emitting device on the substrate.

S403: Forming an auxiliary encapsulation layer on an outer surface of the inorganic layer, and the auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer.

The manufacturing method of the organic light-emitting display panel disposes the auxiliary encapsulation layer on the outer surface of the inorganic layer, and the auxiliary encapsulation layer at least covers a bending region of the inorganic layer and a boundary region of the inorganic layer. Even if the inorganic layer cracks or peels in the bending region and the boundary region, the channel of water and oxygen generated at the cracked place or the peeling place is blocked by the auxiliary encapsulation layer, thereby ensuring the ability of the encapsulation film to block water and oxygen into the organic light-emitting device.

Further, the manufacturing method of the organic light-emitting display panel for a case that the auxiliary encapsulation layer is formed on an outer surface of a second inorganic layer of the organic light-emitting display panel, please refer toFIG. 5. The manufacturing method of the organic light-emitting display panel includes the steps of:

S501: Providing a substrate.

S502: Forming an organic light-emitting device on the substrate.

S503: Forming a first inorganic layer covering the organic light-emitting device.

S504: Forming an organic layer on the first inorganic layer.

S505: Forming a second inorganic layer covering the organic layer and the first inorganic layer.

S506: Forming an auxiliary encapsulation layer on an outer surface of the second inorganic layer, and the auxiliary encapsulation layer at least covers a bending region of the second inorganic layer and a boundary region of the second inorganic layer.

Although the present invention is shown and described by using one or more implementation manners, a person skilled in the art may conceive equivalent variations and modifications based on reading and understanding of the specification and the accompany drawings. The present invention includes all such variations and modifications, which is only limited by the scope of the appended claims. In particular regard to the various functions performed by the foregoing components (such as elements and resources), terms used to describe such components are intended to correspond to any component (unless indicated otherwise) performing specified functions of the components (for example, the components are equivalent in functions), even though structures of the functions are not equivalent to the disclosed structures of functions in the exemplary implementation manners in the specification shown in the specification. In addition, although specific features of the specification are disclosed with respect to only one of several implementation manners, the features may be combined with one or more other features of other implementation manners that are desirable for and advantageous to a given or specific application. Moreover, for the terms “include”, “have”, “contain” or variations thereof being used in specific implementation manners or claims, the terms are intended to be inclusive in a similar manner to that of the term “comprise”. The specification provides various operations of the embodiments. The sequence of some or all operations described should not be explained as that the operations must be related to the sequence. A person skilled in the art will understand replaceable sequences having benefits of the specification. Moreover, it should be understood that, not all operations are mandatory in every embodiment provided in the specification.

The present invention has been disclosed through preferred embodiments; however, the preferred embodiments are not intended to limit the present invention, and a person of ordinary skill in the art can make various modifications and improvements without departing from the spirit and scope of the present invention; therefore, the protection scope of the present invention should be subject to the scope defined by the claims.