Organic light-emitting display device having an encapsulating substrate of high thermal conductivity

An organic light-emitting display device including an encapsulating layer covering a light-emitting element and an encapsulating substrate on the encapsulating layer is provided. The organic light-emitting display device may include metal particles which are dispersed on an outer surface of the encapsulating substrate having a high thermal conductivity, so that damage of the light-emitting element due to external impact may be prevented. And, the organic light-emitting display device may include a capping layer covering the metal particles, so that the surface roughness due to the metal particles may be reduced.

This application claims the priority benefit of Korean Patent Application No. 10-2017-0127392, filed on Sep. 29, 2017, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND

Technical Field

The present disclosure relates to an organic light-emitting display device including an encapsulating substrate having a high thermal conductivity to rapidly emit heat generated in a light-emitting element and/or a driving circuit to the outside.

Discussion of the Related Art

Generally, an electronic appliance, such as a monitor, a TV, a laptop computer and a digital camera, include a display device to realize an image. For example, the display device may include a liquid crystal display device and/or an organic light-emitting display device.

The organic light-emitting display device may include a light-emitting element. The light-emitting element may generate light realizing a specific color. For example, the light-emitting element may include a first electrode, a light-emitting layer and a second electrode, which are sequentially stacked.

The organic light-emitting display device may present external moisture from permeating to the light-emitting element. For example, the organic light-emitting display device may include an encapsulating layer covering the light-emitting element, and an encapsulating substrate disposed on the encapsulating layer.

The light-emitting element and a driving circuit controlling the light-emitting element may generate heat during an operation of realizing an image. The light-emitting layer may be very vulnerable to heat. Thus, the organic light-emitting display device must rapidly emit heat generated in the light-emitting element and/or the driving circuit to the outside. For example, the organic light-emitting display device may include the encapsulating substrate formed of a material having a relatively high thermal conductivity, such as aluminum (Al).

However, since the material having a high thermal conductivity may have a relatively low rigidity, the light-emitting element of the organic light-emitting display device may be damaged by an external impact. In order to prevent damage of the light-emitting element due to the external impact, the organic light-emitting display device may increase a thickness of the encapsulating substrate or add additional layer for reinforcing rigidity on the encapsulating substrate, but the overall thickness of the organic light-emitting display device may be increased.

SUMMARY

Accordingly, embodiments of the present invention are directed to an organic light-emitting display device that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An aspect of the present disclosure is to provide an organic light-emitting display device capable of having high heat radiation efficiency, and preventing damage of a light-emitting element due to an external impact.

Another aspect of the present disclosure is to provide an organic light-emitting display device capable of complementing the rigidity of an encapsulating substrate with minimizing the increase of the overall thickness.

To achieve these objects and other aspects of the inventive concepts, as embodied and broadly described herein, an organic light-emitting display device comprises a light-emitting element on a device substrate. An encapsulating layer is disposed on the light-emitting element. An encapsulating substrate is disposed on the encapsulating layer. A metal coating layer is disposed on the encapsulating substrate. The metal coating layer includes metal particles dispersed on an outer surface of the encapsulating substrate. A capping layer is disposed on the metal coating layer.

A surface of the capping layer opposite to the encapsulating substrate may be a flat surface.

The metal particles may be a magnetic material.

The magnetic material may be one of iron (Fe), nickel (Ni) and cobalt (Co).

The capping layer may be extended on a side surface of the encapsulating substrate.

The capping layer may include a region being in direct contact with the side surface of the encapsulating substrate.

The capping layer may include an organic insulating material.

The encapsulating substrate may include aluminum.

DETAILED DESCRIPTION

Hereinafter, details related to the above objects, technical configurations, and operational effects of the embodiments of the present invention will be clearly understood by the following detailed description with reference to the drawings, which illustrate some embodiments of the present invention. Here, the embodiments of the present invention are provided in order to allow the technical spirit of the present invention to be satisfactorily transferred to those skilled in the art, and thus the present invention may be embodied in other forms and is not limited to the embodiments described below.

In addition, the same or extremely similar elements may be designated by the same reference numerals throughout the specification, and in the drawings, the lengths and thickness of layers and regions may be exaggerated for convenience. It will be understood that, when a first element is referred to as being “on” a second element, although the first element may be disposed on the second element so as to come into contact with the second element, a third element may be interposed between the first element and the second element.

Here, terms such as, for example, “first” and “second” may be used to distinguish any one element with another element. However, the first element and the second element may be arbitrary named according to the convenience of those skilled in the art without departing the technical spirit of the present invention.

The terms used in the specification of the present invention are merely used in order to describe particular embodiments, and are not intended to limit the scope of the present invention. For example, an element described in the singular form is intended to include a plurality of elements unless the context clearly indicates otherwise. In addition, in the specification of the present invention, it will be further understood that the terms “comprises” and “includes” specify the presence of stated features, integers, steps, operations, elements, components, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or combinations.

Embodiment

FIG. 1is a view schematically showing an organic light-emitting display device according to an embodiment of the present invention.FIG. 2is an enlarged view of P region inFIG. 1.

Referring toFIGS. 1 and 2, the organic light-emitting display device according to the embodiment of the present invention may include a device substrate100. The device substrate100may include an insulating material. The device substrate100may include a transparent material. For example, the device substrate100may include glass or plastic.

The device substrate100may include a display area AA and a non-display area NA. The non-display area NA may be disposed outside the display area AA. For example, the non-display area NA may include an edge of the device substrate100.

A thin film transistor200may be disposed on the display area AA of the device substrate100. For example, the thin film transistor200may include a semiconductor pattern210, a gate insulating layer220, a gate electrode230, an interlayer insulating layer240, a source electrode250and a drain electrode260.

The semiconductor pattern210may be disposed close to the device substrate100. The semiconductor pattern210may include a semiconductor material. For example, the semiconductor pattern210may include amorphous silicon or poly-silicon. The semiconductor pattern210may be an oxide semiconductor. For example, the semiconductor pattern210may include IGZO.

The semiconductor pattern210may include a source region, a drain region and a channel region. The channel region may be disposed between the source region and the drain region. The conductivity of the channel region may be lower than the conductivities of the source region and the drain region. For example, the source region and the drain region may include a conductive impurity.

The gate insulating layer220may be disposed on the semiconductor pattern210. A size of the gate insulating layer220may be smaller than a size of the semiconductor pattern210. For example, the gate insulating layer220may overlap with the channel region of the semiconductor pattern210.

The gate insulating layer220may include an insulating material. For example, the gate insulating layer220may include silicon oxide and/or silicon nitride. The gate insulating layer220may include a high-K material. For example, the gate insulating layer220may include hafnium oxide (HfO) or titanium oxide (TiO). The gate insulating layer220may have a multi-layer structure.

The gate electrode230may be disposed on the gate insulating layer220. For example, the gate electrode230may overlap the channel region of the semiconductor pattern210. The gate electrode230may be insulated from the semiconductor pattern210by the gate insulating layer220. For example, a side surface of the gate electrode230may be vertically aligned with a side surface of the gate insulating layer220.

The gate electrode230may include a conductive material. For example, the gate electrode230may include a metal, such as aluminum (Al), chrome (Cr), molybdenum (Mo) and tungsten (W).

The interlayer insulating layer240may be disposed on the semiconductor pattern210and the gate electrode230. The interlayer insulating layer240may be extended beyond the semiconductor pattern210. For example, a side surface of the semiconductor pattern210may be covered by the interlayer insulating layer240.

The interlayer insulating layer240may include an insulating material. For example, the interlayer insulating layer240may include silicon oxide.

The source electrode250may be disposed on the interlayer insulating layer240. The source electrode250may be electrically connected to the source region of the semiconductor pattern210. For example, the source electrode250may overlap with the source region of the semiconductor pattern210. The interlayer insulating layer240may include a contact hole partially exposing the source region of the semiconductor pattern210.

The source electrode250may include a conductor material. For example, the source electrode250may include a metal, such as aluminum (Al), chrome (Cr), molybdenum (Mo) and tungsten (W). The source electrode250may include a material different from the gate electrode230.

The drain electrode260may be disposed on the interlayer insulating layer240. The drain electrode260may be electrically connected to the drain region of the semiconductor pattern210. The drain electrode260may be spaced away from the source electrode250. For example, the drain electrode250may overlap with the drain region of the semiconductor pattern210. The interlayer insulating layer240may further include a contact hole partially exposing the drain region of the semiconductor pattern210.

The drain electrode260may include a conductive material. For example, the drain electrode260may include a metal, such as aluminum (Al), chrome (Cr), molybdenum (Mo) and tungsten (W). The drain electrode260may include a material different from the gate electrode230. The drain electrode260may include a material same as the source electrode250.

A buffer layer110may be disposed between the device substrate100and the thin film transistor200. For example, the buffer layer110may be disposed between the device substrate100and the semiconductor pattern210. The buffer layer110may include an insulating material. For example, the buffer layer110may include silicon oxide.

A lower passivation layer120may be disposed on the thin film transistor200. The lower passivation layer120may prevent damage of the thin film transistor200due to external impact and moisture. For example, the lower passivation layer120may be extended beyond the source electrode250and the drain electrode260. The lower passivation layer120may be in direct contact with the interlayer insulating layer240at the outside of the source electrode250and the drain electrode260. The lower passivation layer120may include an insulating material. The lower passivation layer120may include a material different from the interlayer insulating layer240. For example, the lower passivation layer120may include silicon nitride.

An over-coat layer130may be disposed on the lower passivation layer120. The over-coat layer130may remove a thickness difference due to the thin film transistor200. For example, an upper surface of the over-coat layer130opposite to the device substrate100may be a flat surface.

The over-coat layer130may include an insulating material. The over-coat layer130may include a material different from the lower passivation layer120. The over-coat layer130may include a material having a relatively high fluidity. For example, the over-coat layer130may include an organic insulating material.

A light-emitting element300may be disposed on the over-coat layer130. The light-emitting element300may generate light realizing a specific color. For example, the light-emitting element300may include a first electrode310, a light-emitting layer320and a second electrode330, which are sequentially stacked.

The first electrode310may be disposed close to the over-coat layer130. The light-emitting element300may be controlled by the thin film transistor200. For example, the first electrode310may be electrically connected to the drain electrode260of the thin film transistor200. For example, the lower passivation layer120may include a lower contact hole120hexposing at least portion of the drain electrode260. The over-coat layer130may include an upper contact hole130hoverlapping with the lower contact hole120h. The first electrode310may be extended along a side wall of the lower contact hole120hand a side wall of the upper contact hole130h.

The first electrode310may include a conductive material. The first electrode310may include a transparent material. For example, the first electrode310may be a transparent electrode formed of a transparent material, such as ITO and IZO.

The light-emitting layer320may generate light having luminance corresponding to a voltage difference between the first electrode310and the second electrode330. For example, the light-emitting layer320may include an emitting material layer (EML) having an emission material. The emission material may be an organic material.

The light-emitting layer320may have a multi-layer structure in order to increase luminous efficiency. For example, the light-emitting layer320may further include at least one of a hole injection layer (HIL), a hole transporting layer (HTL), an electron transporting layer (ETL) and an electron injection layer (EIL).

The second electrode330may include a conductive material. The second electrode330may include a material different from the first electrode310. For example, the second electrode330may include a metal having a high reflectance, such as aluminum (Al). Thus, in the organic light-emitting display device according to the embodiment of the present invention, the light generated by the light-emitting layer320may be emitted to the outside through the device substrate100.

In the organic light-emitting display device according to the embodiment of the present invention, a plurality of light-emitting elements300may be disposed on the device substrate100. Each of the light-emitting elements300may be driven, independently. For example, the first electrode310of each light-emitting element300may be separated from the first electrodes210of adjacent light-emitting elements300. A bank insulating layer140may be disposed between the first electrodes310of adjacent light-emitting elements300. The bank insulating layer140may cover an edge of the first electrode310. The light-emitting layer320and the second electrode330may be disposed on a portion of the first electrode310exposed by the bank insulating layer140.

The bank insulating layer140may include an insulating material. For example, the bank insulating layer140may include an organic insulating material. The bank insulating layer140may include a material different from the over-coat layer130.

The portion of the first electrode310exposed by the bank insulating layer140may be spaced away from the thin film transistor200. For example, the bank insulating layer140may overlap the thin film transistor200. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the light traveling toward the device substrate100from the light-emitting element300may be not blocked by the thin film transistor200.

The second electrode330may be extended on the bank insulating layer140. For example, the second electrode330may be extended on a side surface of the bank insulating layer140, a side surface of the over-coat layer130, and a side surface of the lower passivation layer120, which are disposed close to the non-display area NA of the device substrate100. Thus, the organic light-emitting display device according to the embodiment of the present invention may prevent the permeation of the external moisture through the insulating layers stacked between the device substrate100and the second electrode330, and a boundary between adjacent insulating layers.

A color filter400may be disposed between the device substrate100and the light-emitting element300. For example, the color filter400may be disposed between the lower passivation layer120and the over-coat layer130. The thickness difference due to the color filter400may be removed by the over-coat layer130. The color filter400may change a color realized by the light which is emitted from the light-emitting element300. For example, the light-emitting layer320may generate light realizing white color, and the color filter400may realize blue color, red color or green color using the light generated by the light-emitting layer320. The color filter400may have a horizontal width larger than the portion of the first electrode310which is exposed by the bank insulating layer140. Thus, in the organic light-emitting display device according to the embodiment of the present invention, light leakage may be prevented.

An encapsulating layer500may be disposed on the light-emitting element300. The encapsulating layer500may prevent damage of the light-emitting element300due to the external impact and moisture. The encapsulating layer500may be extended on the non-display area NA of the device substrate100. For example, the light-emitting element300may be covered by the encapsulating layer500, completely.

The encapsulating layer500may have a multi-layer structure. For example, the encapsulating layer500may include a lower encapsulating layer510and an upper encapsulating layer520disposed on the lower encapsulating layer510. The light-emitting element300may be covered by the lower encapsulating layer510. The upper encapsulating layer520may include moisture-absorbing particles500p. The moisture-absorbing particles500pmay include a moisture-absorbing material. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the stress applied to the light-emitting element300due to the expansion of the moisture-absorbing particles500pmay be relieved by the lower encapsulating layer510.

The lower encapsulating layer510and the upper encapsulating layer520may include an insulating material. The lower encapsulating layer510and the upper encapsulating layer520may include an adhesive material. The lower encapsulating layer510and the upper encapsulating layer520may include a material which does not require a curing process. For example, the lower encapsulating layer510and the upper encapsulating layer520may include an olefin-based material. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the degradation of the light-emitting layer320due to a process of forming the lower encapsulating layer510and the upper encapsulating layer520may be prevented. The upper encapsulating layer520may include a material different from the lower encapsulating layer510. Therefore, in the organic light-emitting display device according to the embodiment of the present invention, the relief of the stress by the lower encapsulating layer510may be performed, efficiently.

The organic light-emitting display device according to the embodiment of the present invention is described that the encapsulating layer500is in direct contact with the light-emitting element300. However, the organic light-emitting display device according to another embodiment of the present invention may further include an upper passivation layer disposed between the light-emitting element300and the lower encapsulating layer510. The upper passivation layer may prevent the damage of the light-emitting element300due to the external impact and moisture. The upper passivation layer may include an insulating material. The upper passivation layer may have multi-layer structure. For example, the upper passivation may have a structure in which an organic layer formed of an organic insulating material is disposed between inorganic layers formed of an inorganic insulating material.

An encapsulating substrate600may be disposed on the encapsulating layer500. The encapsulating substrate600may be in direct contact with the encapsulating layer500. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the encapsulating substrate600may be coupled to the device substrate100on which the thin film transistor200and the light-emitting element300are formed, by the encapsulating layer500.

The encapsulating substrate600may overlap the display area AA and the non-display area NA of the device substrate100. A size of the encapsulating substrate600may be larger than a size of the encapsulating layer500. For example, a lower surface of the encapsulating substrate600facing the device substrate100may include an edge exposed by the encapsulating layer500. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the defect due to misalignment of the upper encapsulating layer520may be prevented. The size of the encapsulating substrate600may be smaller than a size of the device substrate100. For example, a side surface of the encapsulating substrate600may be disposed between a side surface of the device substrate100and a side surface of the encapsulating layer500.

The encapsulating substrate600may include a material different from the device substrate100. The encapsulating substrate600may provide the radiation path of heat generated in the light-emitting element300and/or the thin film transistor200during an operation of realizing an image. For example, the encapsulating substrate600may include a metal having a relatively high thermal conductivity, such as aluminum (Al).

A metal coating layer700may be disposed on an outer surface of the encapsulating substrate600opposite to the encapsulating layer500. The metal coating layer700may include metal particles700mdispersed on the outer surface of the encapsulating substrate600. That is, in the organic light-emitting display device according to the embodiment of the present invention, the outer surface of the encapsulating substrate600may be coated by the metal particles700m. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the rigidity of the encapsulating substrate600may be compensated with minimizing the increase of the overall thickness. The encapsulating substrate600including the outer surface coated by the metal particles700mmay be harder than a structure in which an additional compensating layer is formed on the encapsulating substrate600. Also, the metal particles700mdispersed on the outer surface of the encapsulating substrate600may have a thermal conductivity higher than the additional compensating layer formed on the encapsulating substrate600. Therefore, in the organic light-emitting display device according to the embodiment of the present invention, the damage of the light-emitting element300due to the external impact may be prevented with minimizing the degree of reducing the thermal conductivity of the encapsulating substrate600. Thereby, in the organic light-emitting display device according to the embodiment of the present invention, the heat radiation efficiency and the reliability may be improved.

A capping layer800may be disposed on the metal coating layer700. The capping layer800may include an insulating material. The capping layer800may cover the metal particles700m. For example, the capping layer may include an organic insulating material having a relatively high fluidity. For example, the capping layer800may include the same material as the over-coat layer130. A surface of the capping layer800opposite to the encapsulating substrate600may be a flat surface. For example, the surface of the capping layer800may be parallel with the outer surface of the encapsulating substrate600. Since the capping layer800includes a material having a high fluidity, a space between the metal particles700mmay be filled by the capping layer800. The capping layer800may include an adhesive material. For example, the capping layer800may include a material same as the lower encapsulating layer510. The capping layer800may include an olefin-based material. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the surface roughness due to the metal particles700mmay be reduced. Therefore, in the organic light-emitting display device according to the embodiment of the present invention, damage due to a rough surface may be prevented.

The metal particles700mmay include a magnetic material. For example, the metal particles700mmay include a ferromagnetic material, such as iron (Fe), nickel (Ni) and cobalt (Co). Thus, in the organic light-emitting display device according to the embodiment of the present invention, the encapsulating substrate600may be moved by jig including a magnetic plate. That is, in the organic light-emitting display device according to the embodiment of the present invention, the location of the encapsulating substrate600may be easily adjusted during a process of coupling the device substrate100and the encapsulating substrate600. And, in the organic light-emitting display device according to the embodiment of the present invention, the surface roughness may be reduced by the capping layer800, so that damage of the encapsulating substrate600and/or the device substrate100due to a process of attaching or detaching the encapsulating substrate600by the transfer jig, may be prevented. Also, in the organic light-emitting display device according to the embodiment of the present invention, the process of attaching or detaching the encapsulating substrate600to the transfer jig may be simplified, so that the process time for coupling the device substrate100and the encapsulating substrate600may be reduced. Therefore, in the organic light-emitting display device according to the embodiment of the present invention, the damage of the light-emitting element300due to the external impact may be prevented with the increase of the process efficiency.

Accordingly, the organic light-emitting display device according to the embodiment of the present invention may including a metal coating layer700including metal particles700mand a capping layer800covering the metal particles700mwhich are sequentially stacked on the outer surface of the encapsulating substrate600having a high thermal conductivity, so that the rigidity of the encapsulating substrate600may be compensated with minimizing the increase of the overall thickness and the degradation of the thermal conductivity efficiency. Also, in the organic light-emitting display device according to the embodiment of the present invention, the process efficiency may be improved by the metal particles700mhaving a magnetic material and the capping layer800. Thus, in the organic light-emitting display device according to the embodiment of the present invention, the heat radiation efficiency, the process efficiency and the reliability may be increased.

The organic light-emitting display device according to the embodiment of the present invention is described that the capping layer800is only disposed on the outer surface of the encapsulating substrate600. However, in the organic light-emitting display device according to another embodiment of the present invention, the capping layer800may be extended on a side surface600sof the encapsulating substrate600, as shown inFIG. 3. For example, the capping layer800may include a region801being in direct contact with the side surface600sof the encapsulating substrate600. Thus, in the organic light-emitting display device according to another embodiment of the present invention, the metal particles may be dispersed on the side surface600sof the encapsulating substrate600, partially. That is, in the organic light-emitting display device according to another embodiment of the present invention, the process margin for dispersing the metal particles on the outer surface of the encapsulating substrate600may be increased. Thereby, in the organic light-emitting display device according to another embodiment of the present invention, the heat radiation efficiency, the process efficiency and the reliability may be increased, efficiently.

In the result, the organic light-emitting display device according to the embodiments of the present invention may include a metal coating layer including metal particles dispersed on an outer surface of an encapsulating substrate, and a capping layer on the metal coating layer. Thus, in the organic light-emitting display device according to the embodiments of the present invention, the rigidity of the encapsulating substrate having a high thermal conductivity may be increase by the metal particles. And, in the organic light-emitting display device according to the embodiments of the present invention, the surface roughness due to the metal particles may be reduced by the capping layer. Therefore, in the organic light-emitting display device according to the embodiments of the present invention, the heat radiation efficiency and the reliability may be improved.