KR102417453B1 - FOgranic Light Emitting Diode Display - Google Patents

Abstract

The present invention relates to an organic light emitting diode display. The organic light emitting diode display device according to the present invention includes a substrate, a barrier film, a dam, a sink hole, and a particle preventing layer. The substrate includes a display area and a non-display area surrounding the display area. The barrier film is bonded to the substrate by means of a pressure-sensitive adhesive. The dam is disposed along the edge of the barrier film in the non-display area on the substrate. The sink hole is disposed on the surface of the substrate adjacent to the dam. And the particle prevention layer is applied in the inner region of the dam, the height of the part adjacent to the dam is lower than the height of the other parts, and is surface-bonded with the pressure adhesive.

Description

Organic Light Emitting Diode Display {FOgranic Light Emitting Diode Display}

The present invention relates to an organic light emitting diode display. In particular, the present invention relates to a dam and sink that maintains a particle preventing layer bonding with an adhesive (or a sealant) to have a flat surface and to be applied within a certain area in bonding the organic light emitting device substrate and the barrier substrate in a surface sealing method. It relates to an organic light emitting diode display having a hole.

Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of a cathode ray tube, have been developed. Such flat panel displays include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electro-luminescence device (EL). etc.

1 is a plan view showing the structure of an organic light emitting diode display device (OLED) using a thin film transistor as an active element according to the prior art. FIG. 2 is a cross-sectional view taken along the cut line I-I' in FIG. 1 , and is a cross-sectional view illustrating a structure of an organic light emitting diode display according to the related art.

1 and 2 , an organic light emitting diode display is formed on a thin film transistor substrate, a thin film transistor substrate on which an organic light emitting diode (OLE) driven in connection with the thin film transistors ST and DT is formed. and a barrier substrate BF bonded to the seal member FS therebetween. The thin film transistor substrate includes a switching thin film transistor ST formed on a transparent substrate SUB, a driving thin film transistor DT connected to the switching thin film transistor ST, and an organic light emitting diode OLE connected to the driving thin film transistor DT. do.

On the glass substrate SUB, the switching thin film transistor ST is formed at the intersection of the gate line GL and the data line DL. The switching thin film transistor ST functions to select a pixel. The switching thin film transistor ST includes a gate electrode SG branching from the gate line GL, a semiconductor layer SA, a source electrode SS, and a drain electrode SD. In addition, the driving thin film transistor DT serves to drive the anode electrode ANO of the pixel selected by the switching thin film transistor ST. The driving thin film transistor DT includes a gate electrode DG connected to the drain electrode SD of the switching thin film transistor ST, a semiconductor layer DA, a source electrode DS connected to the driving current line VDD, and a drain and an electrode DD. The drain electrode DD of the driving thin film transistor DT is connected to the anode electrode ANO of the organic light emitting diode.

2 illustrates a thin film transistor having a top gate structure as an example. In this case, the semiconductor layer SA of the switching thin film transistor ST and the semiconductor layer DA of the driving thin film transistor DT are first formed on the substrate SUB, and a gate electrode is formed on the gate insulating film GI covering the substrate SUB. The fields SG and DG are formed to overlap the central portions of the semiconductor layers SA and DA. In addition, the source electrodes SS and DS and the drain electrodes SD and DD are connected to both sides of the semiconductor layers SA and DA through contact holes. The source electrodes SS and DS and the drain electrodes SD and DD are formed on the intermediate insulating layer IN covering the gate electrodes SG and DG.

In addition, on the outer periphery of the display area in which the pixel area is disposed in the substrate SUB, a gate pad GP formed at one end of each gate line GL, and a data pad DP formed at one end of each data line DL. ), and a driving current pad VDP formed at one end of each driving current line VDD is disposed. Since the gate pad GP and the data pad DP are formed on different layers, defects may occur due to a step difference. In order to solve this step defect, the gate pad GP is exposed by patterning the insulating layer IN covering the gate pad GP, and the same material as the data pad DP is used on the insulating layer IN to apply the same material as the data pad DP to the gate pad GP. It is preferable to further form a gate intermediate pad (GPI) connected thereto.

A passivation layer PAS is applied over the entire substrate SUB on which the switching thin film transistor ST and the driving thin film transistor DT are formed. In addition, contact holes exposing the gate intermediate pad GPI, the data pad DP, the driving current pad VDP, and the drain electrode DD of the driving thin film transistor DT are formed. A planarization layer PL is applied on the display area of the substrate SUB. A contact hole exposing the drain electrode DD of the driving thin film transistor DT is formed by patterning the planarization layer PL. Meanwhile, the planarization layer PL is patterned so that portions of the gate intermediate pad GPI and the data pad GP are completely exposed. The planarization layer PL functions to uniform the roughness of the substrate surface in order to apply the organic material constituting the organic light emitting diode in a smooth planar state.

An anode electrode ANO contacting the drain electrode DD of the driving thin film transistor DT through a contact hole is formed on the planarization layer PL. In addition, even at the outer periphery of the display area in which the planarization layer PL is not formed, the gate is disposed on the gate intermediate pad GPI, the data pad DP, and the driving current pad VDP exposed through the contact holes formed in the passivation layer PAS. A pad terminal GPT, a data pad terminal DPT, and a driving current pad terminal VDPT are respectively formed. In the display area, a bank BA is formed on the substrate SUB except for the pixel area.

An encapsulant FS (or a real material) is applied to the entire surface of the thin film transistor substrate having the structure as described above, and the barrier substrate BF is bonded through the encapsulant FS as a medium. That is, it is preferable that the thin film transistor substrate and the barrier substrate BF are completely sealed and bonded using an encapsulant FS interposed therebetween. The gate pad GP, the gate pad terminal GPT, and the data pad DP and the data pad terminal DPT are exposed to the outside of the barrier substrate BF and are connected to an externally installed device through various connection means.

After completing the thin film transistor substrate, an encapsulant FS is applied on the inner surface. In particular, it is preferable to apply the encapsulant FS only to a location spaced apart from the edge of the barrier substrate BF by a predetermined distance inward.

After aligning the thin film transistor substrate and the barrier substrate BF, the barrier substrate BF is pressed to adhere to the thin film transistor substrate. After the encapsulant FS interposed between the bonded substrates (the barrier substrate and the thin film transistor substrate) is cured and the pressing force is removed, the thin film transistor substrate and the barrier substrate BF are formed by the encapsulant FS as a medium. It has a cotton-sealed structure.

The organic light emitting diode display device described above has a structure in which the data pads DP and the gate pads GP are exposed to the outside of the barrier substrate BF. A data driver and an integrated circuit of the gate driver may be attached here. In this structure, the area in which the driving unit corresponding to the non-display area is mounted occupies a relatively large area.

Recently, a narrow bezel display device in which the area of the non-display area is narrowed has been developed. In this case, the gate driver is formed directly on the substrate SUB without separately mounting the gate driver. At this time, the encapsulant FS is not damaged only when the encapsulant FS is accurately applied.

In addition, the substrate SUB is being developed as a flexible display device by forming a film with high flexibility instead of a rigid glass substrate. In particular, the flexible display device is often bent during use. The encapsulant should not be damaged by such bending stress. To this end, the edges of the encapsulant must be uniformly cured.

When the barrier substrate BF is bonded to the lower substrate using only a cotton encapsulant, there is a limit in preventing the encapsulant from penetrating external particles or air into the interior. As in the prior art, when the bezel area is wide and the non-display area around the display area has a large area, it is possible to block external particles, air, etc. to some extent with only a cotton encapsulant. However, a new structure is needed to develop an organic light emitting diode display suitable for the trend of becoming thinner in order to realize a narrow bezel area and a flexible display. In the prior art, a structure capable of having a surface encapsulation structure while preventing the penetration of external particles or moisture has not been proposed, so the prior art cannot be directly applied to the structures of various organic light emitting diode display devices.

An object of the present invention is to overcome the above problems, and in an organic light emitting diode display in which an organic light emitting diode substrate and a barrier film are bonded, a particle preventing layer for preventing penetration of impurities such as external moisture and air provide more In particular, there is provided an organic light emitting diode display having a dam for maintaining the particle preventing layer without cracks in a predetermined area. Another object of the present invention is to provide an organic light emitting diode display having a sink hole that prevents the particle preventing layer from protruding upward from the boundary surface of a dam or applied beyond the dam. Another object of the present invention is to provide an organic light emitting diode display capable of maintaining a uniform surface of the particle preventing layer without cracks, preventing moisture and air from permeating, and maintaining a constant display quality.

In order to achieve the object of the present invention, an organic light emitting diode display device according to the present invention includes a substrate, a barrier film, a dam, a sink hole, and a particle preventing layer. The substrate includes a display area and a non-display area surrounding the display area. The barrier film is bonded to the substrate by means of a pressure-sensitive adhesive. The dam is disposed along the edge of the barrier film in the non-display area on the substrate. The sink hole is disposed on the surface of the substrate adjacent to the dam. And the particle prevention layer is applied in the inner region of the dam, the height of the part adjacent to the dam is lower than the height of the other parts, and is surface-bonded with the pressure adhesive.

In one example, the sink hole has the shape of a trench disposed along the dam.

For example, in the sink hole, a plurality of well shapes having any one of planar shapes such as a triangle, a square, a hexagon, a circle, and an oval are disposed along the dam.

For example, the well-shaped sink holes have different sizes and shapes and are disposed with different distribution densities.

For example, the sink hole includes a first sink hole and a second sink hole. The first sink hole is disposed on a surface adjacent to the dam at a predetermined distance inwardly. In addition, the second sink hole is disposed on an adjacent surface spaced apart from the dam by a predetermined distance to the outside.

As an example, the pressure adhesive is interposed between the dam and the particle blocking layer while filling the space generated by the height difference of the particle blocking layer applied inside the dam.

For example, the organic light emitting diode display further includes a driving element and a base line. The driving element is disposed on the outer periphery of the display area. The base line extends from the outside of the dam to the inside of the dam on one side of the non-display area and is disposed to surround the driving element.

For example, the organic light emitting diode display device further includes a buffer layer, a thin film transistor, a passivation layer, a planarization layer, an anode electrode, a bank, an organic light emitting layer and a cathode electrode, and a spacer. The buffer layer covers the entire surface of the substrate. The thin film transistor is disposed in the display area on the buffer layer. The protective film covers the entire surface of the substrate on the thin film transistor. The planarization film covers the surface of the display area on the protective film. The anode electrode is connected to the thin film transistor on the planarization film. The bank defines a light emitting area at the anode electrode. The organic light emitting layer and the cathode electrode are laminated with the anode electrode on the bank. And the spacer is arranged on the bank.

For example, the dam is formed by stacking at least one of a planarization film, a bank, and a spacer. The first sink hole is formed by penetrating the passivation layer and the buffer layer covering the substrate, and being recessed to a predetermined depth in the upper surface of the substrate.

In addition, the organic light emitting diode display according to the present invention includes a substrate, a dam, and a sink hole. The sink hole is disposed except for an area in which wiring crossing the dam is disposed. The dam is disposed along a side of the substrate outside the display area of the substrate. The sink hole is disposed along the dam between the dam and the display area.

For example, the display device may further include a ground line disposed on an outer periphery of the display area, wherein the sink hole is disposed between the dam and the ground line.

In one example, the sink hole has the shape of a trench continuously disposed along the dam.

In one example, the sink hole includes a first trench sink hole and a second trench sink hole. The first trench sink hole has a first width and a first length is continuous along the dam. The second trench sink hole is disposed along the dam with a second width and a second continuous length.

For example, the first trench sink hole and the second trench sink hole are disposed to be separated from each other in at least one of a width direction and a length direction of the dam.

For example, in the sink hole, a plurality of well shapes having any one of planar shapes such as a triangle, a square, a hexagon, a circle, and an oval are disposed along the dam in the longitudinal direction of the dam.

For example, a plurality of sink holes having a well shape on a plane figure are disposed in the width direction of the dam.

In one example, it further includes an external sink hole disposed on the outside of the dam, wherein the external sink hole has a different depth from the sink hole.

The organic light emitting diode display device according to the present invention includes a particle blocking layer to prevent impurity particles from penetrating into the display area from the outside. In addition, on the thin film transistor substrate, by including a dam at a position corresponding to the edge of the barrier substrate attached thereon, the particle preventing layer is controlled to be applied stably in a certain area. In bonding the barrier substrate and the thin film transistor substrate through a pressure adhesive and a particle barrier layer, the particle barrier layer is cured in a predetermined area without cracking in the predetermined area. In addition, a sink hole formed by recessing a portion of the substrate is provided inside the dam. Accordingly, due to the particle blocking layer protruding near the dam or overflowing beyond the dam, it is prevented that the surface of the particle blocking layer becomes non-uniform. By bonding the barrier substrate to the thin film transistor substrate while maintaining a uniform surface of the particle blocking layer, display quality can be maintained uniformly over the entire surface of the substrate.

1 is a plan view showing the structure of an organic light emitting diode display using a thin film transistor as an active element according to the prior art;
FIG. 2 is a cross-sectional view taken along the cut line I-I' in FIG. 1 and showing the structure of an organic light emitting diode display according to the related art;
3 is a plan view showing a schematic structure of an organic light emitting diode display device according to a first embodiment of the present invention.
4 is an enlarged plan view of a portion indicated by a circle A in FIG. 3;
5 is a cross-sectional view showing the structure of the organic light emitting diode display according to the first embodiment of the present invention taken along the cut line II-II' in FIG. 4;
6A and 6B are cross-sectional views schematically illustrating a process of bonding a barrier film on a thin film transistor substrate;
7 is a plan view showing a schematic structure of an organic light emitting diode display device according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view showing the structure of an organic light emitting diode display according to a second embodiment of the present invention taken along the cut line III-III' in FIG. 7;
9A to 9C are plan enlarged views illustrating the shape of a sink hole having a trench shape.
10A to 10C are plan enlarged views illustrating the shape of a sink hole having a well shape.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals refer to substantially identical elements throughout. In the following description, if it is determined that a detailed description of known content or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the component names used in the following description may be selected in consideration of ease of writing the specification, and may be different from the component names of the actual product.

<First embodiment>

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 3 to 5 . 3 is a plan view showing a schematic structure of an organic light emitting diode display device according to a first embodiment of the present invention. 4 is an enlarged plan view of a portion indicated by a circle A in FIG. 3 . 5 is a cross-sectional view showing the structure of the organic light emitting diode display according to the first embodiment of the present invention, taken along the cut line II-II' in FIG. 4 .

First, a schematic structure of an organic light emitting diode display device according to the present invention will be described with reference to FIG. 3 . The organic light emitting diode display according to the present invention includes a lower substrate SUB and a barrier film BF. The barrier film BF and the lower substrate SUB are bonded to each other via a surface encapsulant PSA. In the case of a flexible organic light emitting diode display, the lower substrate SUB is made of a film material having excellent flexibility. The barrier film BF is made of a film material for protecting display elements formed on the lower substrate SUB.

The organic light emitting diode display is divided into a display area AA and a non-display area NA. The display area AA is an area for directly displaying video information expressed by the display device, and is disposed in the center of the display device. The non-display area NA is disposed on the periphery of the display area AA and does not perform a display function, but is an area in which necessary elements are disposed. An organic light emitting diode and thin film transistors for driving the organic light emitting diode are formed in the display area AA. In the non-display area NA, a gate driving device GIP, a square device EIP, and a data driving device DIC necessary to perform a display function are disposed. The gate driving element GIP and the square element EIP may be simultaneously formed with the thin film transistor of the display area AA. Meanwhile, the data driving element DIC may be attached to one side of the display device.

The ground line GND is disposed to surround the display area AA and the driving elements GIP and EIP disposed around the display area AA. The ground line GND may be branched from the data driving device DIC. A dam DM is disposed outside the ground line GND. The dam DM is disposed to completely surround the display area AA. A sink hole SH is disposed directly inside the dam DM. The sink hole SH is disposed to surround the display area AA like the dam DM. In particular, the sink holes SH may be discontinuously disposed.

The dam DM is disposed at a position spaced apart from the edge of the barrier film BF by a predetermined distance inward. The dam DM functions to control the particle blocking layer PCL for protecting the display elements formed on the lower substrate SUB from externally penetrating particles (moisture or air) to be stably positioned within a predetermined area. . The dam DM allows the particle blocking layer PCL to be applied while being confined within a certain area, and to maintain a uniform thickness. In FIG. 3 , the particle blocking layer PCL is stably applied to the inner space of the dam DM. The sink hole SH is disposed at a position immediately adjacent to the dam DM in the inner space of the dam DM. The sink hole SH prevents the particle blocking layer PCL from overflowing or protruding upward in the vicinity of the dam DM.

For example, the particle blocking layer (PCL) is applied in a high-density liquid-like state. When the material of the dam (DM) has hydrophobicity, the particle blocking layer (PCL) rises up at the part in contact with the dam (DM). There may be cases where it goes up. That is, the coated surface of the particle blocking layer PCL may not be flat, and the height of the edge portion adjacent to the dam DM may be higher than the central portion. The sink hole SH is formed on the inner surface of the lower substrate SUB adjacent to the dam DM to induce the surface of the particle blocking layer PCL adjacent to the dam DM to be applied at a slightly lower height than the other portions.

The data driver DIC is disposed on one side, for example, an upper side of the lower substrate SUB. In particular, the data driver DIC may be attached to the lower substrate SUB as an integrated circuit device. The gate driver GIP is disposed on one side, for example, a left side of the lower substrate SUB. The square element EIP is disposed on the other side of the lower substrate SUB, for example, on the right side. The gate driver GIP and the tetragonal element EIP may also be made as a direct circuit element and attached to the lower substrate SUB. Alternatively, in order to narrow the widths of the left and right non-display areas NA, display elements may be directly formed in the non-display area NA in the process of forming the display elements in the display area AA. 3 shows the latter case.

Hereinafter, the structure of the organic light emitting diode display according to the first embodiment of the present invention will be described in detail with further reference to FIGS. 4 and 5 . The organic light emitting diode display according to the first embodiment of the present invention includes a lower substrate SUB, and a barrier film BF surface-bonding the lower substrate SUB.

Thin film transistors ST and DT and organic light emitting diode OLE are formed in display area AA of lower substrate SUB. The display area AA includes a plurality of pixel areas PA defined by crossing the data line DL and the driving current line VDD connected to the data driver DIC and the gate line GL connected to the gate driver GIP. ) are arranged in a matrix manner. In each pixel area PA, the switching thin film transistor ST, the driving thin film transistor DT connected to the switching drain electrode SD, and the organic light emitting diode OLE connected to the driving drain electrode DD are formed.

In the non-display area NA, gate driving thin film transistors formed simultaneously with the switching and driving thin film transistors ST and DT are formed. A planarization layer PL is coated on the thin film transistor of the gate driver GIP and the switching and driving thin film transistors ST and DT. An anode electrode ANO is formed in the pixel area PA on the planarization layer PL. A bank BA is coated on the lower substrate SUB on which the anode electrode ANO is formed.

In the bank BA, an opening defining a light emitting area in the anode ANO is formed. An organic light emitting layer OL and a cathode electrode CAT are successively stacked on the bank BA. An organic light emitting diode OLE formed by laminating an anode ANO, an organic light emitting layer OL, and a cathode CAT is formed in the opening formed in the bank BA in the pixel area PA.

A ground line GND is disposed outside the gate driver GIP. The ground line GND may be formed of any one of metal materials disposed in the display area AA. 5 illustrates a case in which the gate electrodes SG and DG are formed of the same material. A passivation layer PAS covers the surface of the lower substrate SUB on which the ground wiring GND, the gate driver GIP, and the thin film transistors ST and DT are formed. The planarization layer PL and the bank BA may be applied only to the display area AA.

The barrier substrate BF is bonded to the lower substrate SUB on which the display elements are completed. In this case, spacers SP may be further formed on the bank BA to make the bonding interval constant. A particle blocking layer PCL is filled between the barrier substrate BF and the lower substrate SUB to prevent moisture and air from penetrating into the display device from the outside. The particle blocking layer (PCL) is made of a thermosetting organic material.

After the particle blocking layer PCL is applied to the surface of the lower substrate SUB, the barrier film BF is bonded. Since the particle blocking layer PCL is not uniformly pushed, the thickness of the particle blocking layer PCL may not be uniform at the edge portion. Alternatively, the edge of the particle blocking layer (PCL) may not form a straight line and may create a jagged boundary line. Due to this non-uniformity, a crack may occur at the edge of the particle blocking layer PCL, and external moisture or air may penetrate into the display area AA through the crack. As a result, the particle blocking layer PCL may not function properly, and the lifespan of the display device may be shortened or display quality of the display device may be deteriorated.

In order to prevent this problem, a dam DM is formed in a portion corresponding to a slightly inner side of the edge of the barrier film BF in the lower substrate SUB. The dam DM is preferably formed by stacking the planarization layer PL, the bank BA, and/or the spacer SP. Accordingly, the height of the dam DM may be substantially similar to the height of the uppermost layer of the spacer SP in the display area AA. That is, the height of the dam DM may be approximately equal to or slightly lower than the bonding interval between the lower substrate SUB and the barrier film BF.

The particle blocking layer PCL applied to the surface of the lower substrate SUB is stably applied inside the area defined by the dam DM, and uniform surface flatness can be maintained during bonding with the barrier film BF. . Accordingly, cracks and/or lifting with other material layers that may occur due to non-uniform boundary lines or non-uniform thicknesses at the edges of the particle blocking layer PCL do not occur. That is, it is possible to fundamentally block the starting points of the path through which particles or air and/or moisture from the outside can penetrate.

However, in some cases, the particle blocking layer PCL may exceed the dam DM. When the particle blocking layer PCL passes over the dam DM, cracks may occur, and the cracks may propagate to the particle blocking layer PCL applied inside the dam DM. The propagation of these defects can create pathways for external moisture or air to penetrate.

Alternatively, even if the particle blocking layer PCL does not exceed the dam DM, it may be hardened by protruding above the height of the dam DM at the inner boundary of the dam DM. In the case of protruding upward from the boundary portion of the dam DM, the surface of the barrier film BF is not smooth but uneven after bonding with the barrier film BF. As a result, when the display device displays video information, light leakage or color distortion may occur due to this uneven edge.

As such, it is necessary to ensure that the height of the particle blocking layer PCL at the edge portion of the dam DM can be applied at a stable height lower than that of the dam DM. In the present invention, a sink hole SH is further provided at an inner lower portion of the dam DM. The sink hole SH may be formed by removing the passivation layer PAS, the intermediate insulating layer IN, and the buffer layer BF. If necessary, a deeper sink hole SH may be formed by further removing a partial thickness of the lower substrate SUB in the depth direction.

Due to the sink hole SH, the particle blocking layer PCL may have a height slightly recessed downward near the dam DM. When the barrier film BF is bonded in this state, the particle blocking layer PCL may have a stable height without overflowing or protruding. In particular, when a bonding force is applied from the outer surface of the barrier film BF toward the lower substrate SUB, the surface of the particle blocking layer PCL may be uniformly maintained. In this state, thermal curing is performed to cure the particle blocking layer (PCL). A pressure-sensitive adhesive PSA is applied to the lower surface of the barrier film BF. Accordingly, by pressing the barrier film BF, it is completely in close contact with the upper surface of the particle blocking layer PCL.

The sink hole SH may be formed in a continuous trench shape along the dam DM. Alternatively, the shape on a plan view may have a polygonal shape such as a triangle, a square, and a hexagon, or a shape such as a circle and an ellipse, and may be formed in a well shape having a predetermined depth. When the sink hole SH has a well shape, a plurality of sink holes SH may be disposed at intervals along the dam DM. An interval at which the sink holes SH are disposed may be uniformly disposed or may be irregularly disposed. As another method, in the case of forming the well-shaped sink holes SH, the sink holes SH may have different sizes and may be arranged at irregular intervals.

The sink hole SH may be formed by etching even a part of the lower substrate SUB. In this case, the sink hole SH cannot be formed in the portion where the wiring crosses. For example, on the side where the data driver DIC is disposed, the ground line GND passes across the dam DM. It is preferable that the sink hole SH be disposed in such a place to avoid the ground wiring GND. In this case, it is preferable to dispose well-shaped sink holes SH on the right and left sides of the ground wiring GND, respectively, and the spacing may be different from the spacing of the sink holes SH disposed elsewhere. In addition, in the portion where the data lines DL are disposed, several wires may be disposed in a group. When a sufficient space is secured between the wire group and the wire group, a sink hole SH is selectively formed in the space. can be formed

Hereinafter, in order to explain the functions of the dam DM and the sink hole SH in more detail, a process of bonding the lower substrate SUB and the barrier film BF will be described. 6A and 6B are cross-sectional views schematically illustrating a process of bonding a barrier film on a thin film transistor substrate.

Referring to FIG. 6A , a particle blocking layer PCL is coated on the lower substrate SUB on which the thin film transistors ST and DT, the organic light emitting diode OLE, the dam DM, and the sink hole SH are formed. The particle blocking layer PCL has a uniform height in the inner space of the dam DM, and is in a stable coating state. In particular, the particle blocking layer PCL has a slightly lower height than the other portions (the central portion of the substrate) in the portion adjacent to the dam DM in which the sink hole SH is formed. The height difference is indicated by a dotted line.

The particle blocking layer PCL is applied to a thickness corresponding to the bonding interval between the barrier film BF to be bonded later and the lower substrate SUB. For example, it is applied to about the height of the spacer SP. The dam DM may be formed using only the spacer SP, or may be stacked with the bank BN or the planarization layer PL. Accordingly, the height of the dam DM is almost similar to the height of the spacer SP, but may be slightly lower. Accordingly, the height of the particle blocking layer PCL applied to the display area AA is higher than that of the dam DM. However, the height of the particle blocking layer PCL near the dam DM in which the sink hole SH is disposed has a slightly lower height than that of the dam DM. That is, near the dam DM, the particle blocking layer PCL is applied with a height that does not exceed the dam DM. In this state, the particle blocking layer (PCL) is cured in a heat treatment process.

6B , the barrier film BF is aligned with the lower (thin film transistor) substrate SUB. On the lower surface of the barrier film BF, a pressure adhesive PSA is applied to the entire surface. The pressure adhesive (PSA) has a flattening property, so that when it is bonded on a stepped surface, it can achieve bonding while filling the step by pressing the bonding force. The barrier film (BF) is bonded to the particle blocking layer (PCL) so as to be surface-adhesive. When pressed with a certain amount of cohesive force, the pressure adhesive (PSA) fills the space caused by the difference in height between the central and edge parts generated on the upper surface of the particle blocking layer (PCL), and the barrier film (BF) with the particle blocking layer (PCL) Make it into a cohesive state. As a result, as shown in FIG. 5 , the barrier film BF is completely surface-bonded with the lower substrate SUB via the particle blocking layer PCL and the pressure adhesive PSA.

In the organic light emitting diode display, it is being developed as a product that is thinner, lighter, has little bezel area, or can be freely bent. In order to realize a lighter and no bezel area, driving elements may be formed simultaneously with the display element. In this case, when bonding the thin film transistor substrate and the barrier film, a surface bonding structure using a surface encapsulant may be used to secure a large bonding area.

It is necessary to control the particle barrier layer to have the correct borders within the correct area and to maintain a uniform thickness. To this end, in the present invention, a dam is formed in a region close to the edge of the barrier film bonded to the thin film transistor substrate. The dam controls the particle prevention layer to be applied stably within a certain area. By providing the dam, the particle-preventing layer is stably applied in a certain area with a precise boundary rim. In this case, if the particle barrier layer protrudes upward near the dam or is severe, it may pass over the dam. To prevent this, in the first embodiment of the present invention, a sink hole is further provided on the inner lower surface of the dam in the lower substrate. Thereby, the particle barrier layer is applied so as to have a slightly lower height than the other parts near the dam. As a result, it is also possible to prevent the particle barrier layer from going over the dam or from protruding upward in the vicinity of the dam.

In the above description, the relationship between the dam and the sink hole has been mainly described. In the present invention, the sink hole may be formed in various shapes. Hereinafter, various shapes and arrangements of the sink hole will be described in detail with reference to the drawings.

9A to 9C are plan enlarged views illustrating the shape of a sink hole having a trench shape. First, referring to FIG. 9A , as the simplest structure, the sink hole SH has a constant width and has a trench shape continuously formed along the length direction of the dam DM. The trench-shaped sink hole SH may form a single body connected as a whole in the same way as the dam DM. In some cases, the driving element may be disposed outside the dam DM, so that a wiring such as the ground line GND may extend from the driving element across the dam DM. In this case, since the dam DM is disposed thereon, it may be disposed to have a continuous length over all surfaces of the substrate SUB. However, when the sink hole SH is formed by being recessed to the substrate SUB, the wiring may be damaged. Accordingly, the sink hole SH cannot be formed in a predetermined area, for example, a portion through which the ground line GND passes. In this case, it is preferable to separate the sink hole SH in the longitudinal direction of the dam DM.

Referring to FIG. 9B , it is preferable that the sink hole SH have a sufficient area to lower the height of the particle blocking layer PCL from the edge portion. In particular, there may be a portion in which the sink hole SH cannot be formed in a portion such as a portion through which wiring passes. In this part, the width of the sink hole SH formed around it may be formed to be wider. For example, the sink hole SH has a first width along the dam DM and has a second width and a second length along the first trench sink hole TH1 and the dam DM, which are formed to be continuous with the first length. The second trench sink hole TH2 may be continuously disposed. The first trench sink hole TH1 and the second trench sink hole TH2 may be disposed separately from each other in the longitudinal direction of the dam DM, or may be connected as a single body.

Referring to FIG. 9C , the sink hole SH may have the shape of two trenches arranged to be separated in the width direction of the dam DM. For example, the first trench sink hole TH1 having a first width and the second trench sink hole TH1 having a first width are disposed adjacent to the dam DM and spaced a predetermined distance apart from the first trench sink hole TH1 in the width direction of the dam DM. It may include a first trench sink hole TH1 having a width and formed in the longitudinal direction of the dam DM. In this case, the first width and the second width may have the same width or different widths. In addition, while the entire first trench sink hole TH1 is formed to have a constant width, the second trench sink hole TH2 has a different width in a specific portion determined to be necessary to effectively lower the edge height of the particle blocking layer PCL. It can also be formed to have

10A to 10C are plan enlarged views illustrating the shape of a sink hole having a well shape. First, referring to FIG. 10A , when the sink hole SH is formed in a well shape, when viewed from a plan view, the sink hole SH may have any one shape among polygons such as a triangle, a square, and a hexagon. Alternatively, it may have a planar shape such as an ellipse or a circle. As shown in FIG. 10A , the sink hole SH having a well shape is not continuously formed like a trench, but several individual sink holes SH are arranged along the dam DM. In this case, the manner in which the sink holes SH are arranged may be varied. For example, sink holes SH having the same shape and the same size may be disposed along the dam DM at regular intervals.

Also, as shown in FIG. 10B , sink holes SH having a well shape may be disposed at non-uniform intervals. In particular, the distribution density of the sink holes SH may be higher in a region through which the ground wiring GND where the sink hole SH is not formed, compared to other regions.

Alternatively, as shown in FIG. 10C , two or a plurality of sink holes SH having a well shape may be arranged adjacent to each other in the width direction of the dam DM. That is, the sink holes SH may be arranged in two or more rows along the longitudinal direction of the dam DM. Of course, even in this case, the distribution density of the sink holes SH may be arranged differently for each area.

<Second embodiment>

In the first embodiment, a thin film transistor substrate having a sink hole formed on the surface of the substrate inside the dam is proposed. In the first embodiment, the dam and sink hole function to prevent the particle barrier layer from being applied beyond the dam. However, in an actual process, in particular, in the case of a thin film transistor substrate in which the bezel area is minimized, it is quite difficult to accurately limit the particle barrier layer to the inner space of the dam. The second embodiment proposes a thin film transistor substrate having a structure in which the bezel area is minimized and the bezel area is prevented from being widened due to the overflowed particle prevention layer even if a part of the particle blocking layer is applied beyond the dam.

Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8 . 7 is a plan view showing a schematic structure of an organic light emitting diode display device according to a second embodiment of the present invention. FIG. 8 is a cross-sectional view showing the structure of an organic light emitting diode display according to a second embodiment of the present invention, taken along the cut line III-III' in FIG. 7 .

The organic light emitting diode display device according to the second embodiment of the present invention has substantially the same basic configuration as that of the first embodiment. Accordingly, the same components are denoted by the same reference numerals. In addition, a description of the same configuration as that of the first embodiment will be omitted herein.

A general structure includes a lower substrate SUB, and a barrier film BF surface-bonding the lower substrate SUB. The barrier substrate BF is bonded to the lower substrate SUB on which the display elements are completed. In this case, spacers SP may be further formed on the bank BA to make the bonding interval constant. A particle blocking layer PCL is filled between the barrier substrate BF and the lower substrate SUB to prevent particles, moisture, and air from penetrating into the display device from the outside. The particle blocking layer (PCL) is made of a thermosetting organic material.

After the particle blocking layer PCL is applied to the surface of the lower substrate SUB, the barrier film BF is bonded. Since the particle blocking layer PCL is not uniformly pushed, the thickness of the particle blocking layer PCL may not be uniform at the edge portion. Alternatively, the edge of the particle blocking layer (PCL) may not form a straight line and may create a jagged boundary line. Due to this non-uniformity, a crack may occur at the edge of the particle blocking layer PCL, and external moisture or air may penetrate into the display area AA through the crack. As a result, the particle blocking layer PCL may not function properly, and the lifespan of the display device may be shortened or display quality of the display device may be deteriorated.

In order to prevent this problem, a dam DM is formed in a portion corresponding to a slightly inner side of the edge of the barrier film BF in the lower substrate SUB. The dam DM is preferably formed by stacking the planarization layer PL, the bank BA, and/or the spacer SP.

As described in the first embodiment, it is necessary to apply the particle blocking layer PCL at a stable height lower than that of the dam DM at the edge of the dam DM. In the present invention, a first sink hole SH1 is provided at an inner lower portion of the dam DM. The first sink hole SH1 may be formed by removing the passivation layer PAS, the intermediate insulating layer IN, and the buffer layer BF. If necessary, a portion of the lower substrate SUB may be further removed to form the first sink hole SH1 .

Due to the first sink hole SH1 , the particle blocking layer PCL may have a height slightly recessed downward near the dam DM. When the barrier film BF is bonded in this state, the particle blocking layer PCL may have a stable height without overflowing or protruding. In particular, when a bonding force is applied from the outer surface of the barrier film BF toward the lower substrate SUB, the surface of the particle blocking layer PCL may be uniformly maintained. In this state, thermal curing is performed to cure the particle blocking layer (PCL). A pressure-sensitive adhesive PSA is applied to the lower surface of the barrier film BF. Accordingly, by pressing the barrier film BF, it is completely in close contact with the upper surface of the particle blocking layer PCL.

In addition, a second sink hole SH2 is further provided at an outer lower portion of the dam DM. Like the first sink hole SH1 , the second sink hole SH2 may be formed by removing the passivation layer PAS, the intermediate insulating layer IN, the buffer layer BF, and the like. If necessary, a portion of the lower substrate SUB may be further removed to form the second sink hole SH2 .

The first and second sink holes SH1 and SH2 may be formed in a continuous trench shape along the dam DM. Alternatively, it may be formed in a rectangular, hexagonal, circular, oval, or polygonal well shape, and these wells may be disposed at intervals along the dam DM. The first and second sink holes SH1 and SH2 may be formed by etching even a portion of the lower substrate SUB. Therefore, it cannot be formed in the portion where the wiring crosses. For example, the first and second sink holes SH1 and SH2 may not be formed on the upper side where the data driver DIC is disposed. If necessary, the first and second sink holes SH1 and SH2 may be selectively formed only in portions in which a sufficient space is secured between the wiring and the wiring.

The second sink hole SH2 is formed so that, when the particle blocking layer PCL is partially applied to the outside beyond the dam DM, the overflowing particle blocking layer PCL does not extend to an area far away from the dam DM. will be. When a portion of the particle blocking layer (PCL) applied in the structure without the second sink hole (SH2) is cured while crossing the dam (DM), the particle blocking layer (PCL) may be exposed to a considerable distance outside the dam (DM). .

However, when the second sink hole SH2 is formed on the surface of the substrate SUB adjacent to the outside of the dam DM, the overflowing particle blocking layers PCL are impregnated into the second sink hole SH2 . Therefore, even if the particle blocking layer PCL is applied beyond the dam DM, it does not extend far from the dam DM. A dotted line in FIG. 8 indicates an area in which the particle blocking layer PCL applied beyond the dam DM is extended when the second sink hole SH2 does not exist. As indicated by the solid line, when there is the second sink hole SH2, since the particle blocking layer PCL exists only up to the second sink hole SH, the area where the particle blocking layer PCL is exposed can be minimized. have. This also helps to minimize the bezel area.

Here, the second sink hole SH2 serves to prevent the particle blocking layer PCL beyond the dam DM from excessively extending to the outside of the substrate SUB, and does not need to be very deep. Accordingly, it may be sufficient to form the second sink hole SH2 by removing the buffer layer BUF, the insulating layers GI and IN, and the passivation layer PAS applied on the substrate SUB. Of course, if necessary, the substrate SUB may be formed by further recessing a part of the depth.

Also, the shapes of the first and second sink holes SH1 and SH2 may have various shapes as described in the first embodiment. Also, the arrangement method may be variously distributed as described in the first embodiment.

Those skilled in the art from the above description will be able to see that various changes and modifications can be made without departing from the technical spirit of the present invention. Accordingly, the present invention should not be limited to the contents described in the detailed description, but should be defined by the claims.

ST: switching thin film transistor DT: driving thin film transistor
SG: switching gate electrode DG: driving gate electrode
SS: switching source electrode DS: driving source electrode
SD: switching drain electrode DD: driving drain electrode
SA: switching semiconductor layer DA: driving semiconductor layer
GL: gate wiring DL: data wiring
VDD: drive current wiring GP: gate pad
DP: Data Pad GPT: Gate Pad Terminal
DPT: data pad terminal VDP: drive current pad
VDPT: drive current pad terminal GPH: gate pad contact hole
DPH: data pad contact hole VPH: drive current pad contact hole
GI: gate insulating film IN: insulating film
PAS: protective film PL: planarization film
OL: organic light-emitting layer OLE: organic light-emitting diode
FS: Seal BF: Barrier Film
DM: Dam SH: Sink Hole

Claims (18)

a substrate including a display area and a non-display area surrounding the display area;
a barrier film bonded to the substrate with a cotton encapsulant as a medium;
a dam disposed along an edge of the barrier film in the non-display area on the substrate;
a sink hole disposed on a surface of the substrate adjacent to the dam; and
It enters the sink hole in the inner region of the dam and is applied so that the height of the portion adjacent to the dam is lower than the height of the other portions, and comprising a particle preventing layer bonded to the cotton encapsulant,
The sink hole is
a first sink hole disposed on a surface adjacent to the dam by a predetermined distance inward; and
and a second sink hole disposed on a surface adjacent to the dam by a predetermined distance to the outside.
The method of claim 1,
The sink hole is
An organic light emitting diode display having a trench shape disposed along the dam.
The method of claim 1,
The sink hole is
An organic light emitting diode display in which a plurality of well shapes having any one of planar shapes such as a triangle, a square, a hexagon, a circle, and an oval are disposed along the dam.
4. The method of claim 3,
The well-shaped sink holes are
Organic light emitting diode display devices with different sizes and shapes and different distribution densities.
delete The method of claim 1,
The cotton encapsulant,
An organic light emitting diode display device in which the barrier film is interposed between the dam and the particle blocking layer while filling a space generated by a height difference between the particle blocking layers applied inside the dam.
The method of claim 1,
a driving element disposed on an outer periphery of the display area; and
a base line extending from the outside of the dam to the inside of the dam at one side of the non-display area and disposed to surround the driving element;
The sink hole is
An organic light emitting diode display device disposed to be spaced apart from the ground line by a predetermined distance in a portion where the base line crosses the dam.
The method of claim 1,
The substrate is
a buffer layer covering the entire surface of the substrate;
a thin film transistor disposed in the display area on the buffer layer;
a protective film covering the entire surface of the substrate on the thin film transistor;
a planarization layer covering a surface of the display area on the passivation layer;
an anode electrode connected to the thin film transistor on the planarization layer;
a bank defining a light emitting region in the anode electrode;
an organic light emitting layer and a cathode electrode stacked with the anode electrode on the bank; and
The organic light emitting diode display device further comprising a spacer disposed on the bank.
9. The method of claim 8,
The dam is
at least one of the planarization layer, the bank, and the spacer is stacked;
The sink hole is
An organic light emitting diode display device penetrating through the passivation layer and the buffer layer covering the substrate and recessed to a predetermined depth in the upper surface of the substrate.
Board;
a dam disposed along a side of the substrate outside the display area of the substrate;
a sink hole disposed along the dam between the dam and the display area; and
It enters the sink hole in the inner region of the dam and is applied so that the height of the portion adjacent to the dam is lower than the height of the other portions, and includes a particle preventing layer bonded to a cotton encapsulant,
The sink hole is disposed except for an area in which a wiring crossing the dam is disposed,
The organic light emitting diode display device further comprising an external sink hole disposed outside the dam.
11. The method of claim 10,
The sink hole is disposed adjacent to the dam.
11. The method of claim 10,
Further comprising a base line disposed on the outer periphery of the display area,
The sink hole is disposed between the dam and the ground line.
11. The method of claim 10,
The sink hole is
An organic light emitting diode display having a trench shape continuously disposed along the dam.
11. The method of claim 10,
The sink hole is
a first trench sink hole having a first width and a first length continuous along the dam; and
and a second trench sink hole having a second width and a second length continuous along the dam.
15. The method of claim 14,
The first trench sink hole and the second trench sink hole are disposed to be separated from each other in at least one of a width direction and a length direction of the dam.
11. The method of claim 10,
The sink hole is
An organic light emitting diode display device in which a plurality of wells having any one of planar shapes such as a triangle, a square, a hexagon, a circle, and an oval are disposed along the dam in a longitudinal direction of the dam.
17. The method of claim 16,
An organic light emitting diode display in which a plurality of sink holes having a well shape on the planar figure are disposed in a width direction of the dam.
11. The method of claim 10,
The external sink hole has a depth different from that of the sink hole.

Images