Display device

A display device capable of reducing a non-display area includes a substrate including at least one hole area disposed within an emission area, and at least one blocking hole passing through inorganic insulating films disposed beneath a light emitting element while including upper and lower insulating films made of different materials. Side surfaces of the upper inorganic insulating film exposed through the blocking hole protrude beyond side surfaces of the lower inorganic insulating film exposed through the blocking hole, respectively. Accordingly, it is possible to minimize a bezel area, which is a non-display area, and to disconnect a light emitting stack by the blocking hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Republic of Korea Patent Application No. 10-2018-0145431 filed on Nov. 22, 2018, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND

Field

The present disclosure relates to a display device, and more particularly to a display device capable of reducing a non-display area.

Discussion of the Related Art

An image display device, which renders a variety of information on a screen, is a core technology of the information age. Such an image display device is developing towards enhanced thinness, enhanced lightness, and enhanced portability as well as enhanced performance. In connection with this, a flat display device capable of eliminating disadvantages of heavy and bulky structures of cathode ray tubes (CRTs) is highlighted.

Representative examples of such a flat display device may include a liquid crystal display (LCD) device, a plasma display panel (PDP), an organic light emitting display (OLED) device, an electrophoretic display (ED) device, and the like.

Such a flat display device is employed in various types of appliances such as a television (TV), a monitor and a portable phone, and is being further advanced through addition of a camera, a speaker and a sensor thereto. However, the camera, the speaker, the sensor and the like are disposed in a non-display area of the display device and, as such, a bezel area, which is a non-display area, increases. For this reason, conventional display devices have a problem in that a display area is reduced.

SUMMARY

Accordingly, the present disclosure is directed to a display device that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An object of the present disclosure is to provide a display device capable of reducing a non-display area.

To achieve these objects and other advantages and in accordance with the purpose of the disclosure, as embodied and broadly described herein, a display device includes a substrate including at least one hole area disposed within an emission area, and at least one blocking hole passing through inorganic insulating films disposed beneath a light emitting element while including upper and lower insulating films made of different materials. Side surfaces of the upper inorganic insulating film exposed through the blocking hole protrude beyond side surfaces of the lower inorganic insulating film exposed through the blocking hole, respectively. Accordingly, it may be possible to minimize a bezel area, which is a non-display area, and to disconnect a light emitting stack by the blocking hole.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2, a display device is illustrated. The display device includes an active area AA and a pad area PDA.

A plurality of pads122is formed in the pad area PDA, to supply drive signals to a plurality of signal lines disposed in the active area AA, respectively. Here, each signal line106includes at least one of a scan line SL, a data line DL, a high-voltage (VDD) supply line or a low-voltage (VSS) supply line.

The active area AA includes emission areas EA, a bezel area BA and a hole area HA.

Unit pixels, each of which includes a light emitting element130, are disposed in the emission areas EA, respectively. Each unit pixel may be constituted by red (R), green (G), and blue (B) subpixels, as illustrated inFIG. 1, or may be constituted by red (R), green (G), blue (B), and white (W) subpixels. Each subpixel includes one light emitting element130, and a pixel driving circuit for independently driving the light emitting element130.

The pixel driving circuit includes a switching transistor TS, a driving transistor TD, and a storage capacitor Cst.

The switching transistor TS turns on when a scan pulse is supplied to a corresponding scan line SL. In this state, a data signal supplied to a corresponding data line DL is supplied to the capacitor Cst and a gate electrode of the driving transistor TD via the switching transistor TS.

The driving transistor TD controls current I supplied from a corresponding high-voltage (VDD) supply line to the light emitting element130, in response to the data signal supplied to the gate electrode thereof, thereby adjusting the amount of light emitted from the light emission element130. Even when the switching transistor TS turns off, the driving transistor TD supplies constant current I by a voltage charged in the storage capacitor Cst until a data signal of a next frame is supplied and, as such, the light emission element130maintains emission of light.

FIG. 2illustrates a display device according to a first embodiment of the present disclosure. As illustrated inFIG. 2, the driving transistor TD, which is designated by reference numeral “150”, includes an active layer154disposed on an active buffer layer114, a gate electrode152overlapping with the active layer154under the condition that a gate insulating film116is interposed between the active layer154and the gate electrode152, and a source electrode156and a drain electrode158formed on an interlayer insulating film102while contacting the active layer154.

The active layer154is made of at least one of an amorphous semiconductor material, a polycrystalline semiconductor material, or an oxide semiconductor material. The active layer154includes a channel region, a source region, and a drain region. The channel region overlaps with the gate electrode152under the condition that the gate insulating film116is interposed between the channel region and the gate electrode152and, as such, the channel region is defined between the source electrode156and the drain electrode158. The source region is electrically connected to the source electrode156via a source contact hole124S passing through the gate insulating film116and the interlayer insulating film102. The drain region is electrically connected to the drain electrode158via a drain contact hole124D passing through the gate insulating film116and the interlayer insulating film102.

A multi-buffer layer112and an active buffer layer114are disposed between the active layer154and a substrate101. The multi-buffer layer112functions to delay diffusion of moisture and/or oxygen penetrating into the substrate101. The active buffer layer114performs functions of protecting the active layers154and blocking various kinds of defects propagated from the substrate101. At least one of the multi-buffer layer112, the active buffer layer114, or the substrate101has a multilayer structure.

In this case, the uppermost layer of the multi-buffer layer112contacting the active buffer layer114is made of a material having etching characteristics different from those of the remaining layers of the multi-buffer layer112, the active buffer layer114, and the gate insulating layer116. The uppermost layer of the multi-buffer layer112contacting the active buffer layer114is made of one of SiNxand SiOx. The remaining layers of the multi-buffer layer112, the active buffer layer114, and the gate buffer layer116may be made of the other of SiNxand SiOx. For example, the uppermost layer of the multi-buffer layer112contacting the active buffer layer114is made of SiNx, whereas the remaining layers of the multi-buffer layer112, the active buffer layer114, and the gate buffer layer116are made of SiOx.

The light emitting element130includes an anode132connected to the drain electrode158of the driving transistor (TD)150, at least one light emitting stack134formed on the anode132, and a cathode136formed on the light emitting stack134, to be connected to a low-voltage (VSS) supply line. Here, the low-voltage (VSS) supply line supplies a voltage lower than a high voltage supplied through a high-voltage (VDD) supply line.

The anode132is electrically connected to the drain electrode158of the driving transistor (TD)150exposed through a pixel contact hole126passing through a planarization layer104disposed on the driving transistor (TD)150. The anode132of each subpixel is disposed on the planarization layer104without being covered by a bank138such that at least a part of the anode132is exposed.

When the anode132as described above is applied to a bottom emission type organic light emitting display device, the anode132is constituted by a transparent conductive film made of indium tin oxide (ITO) or indium zinc oxide (IZO). On the other hand, when the anode132is applied to a top emission type organic light emitting display device, the anode132is formed to have a multilayer structure including a transparent conductive film and an opaque conductive film having high reflection efficiency. The transparent conductive film is made of a material having a relatively high work function, for example, indium tin oxide (ITO) or indium zinc oxide (IZO). The opaque conductive film is formed to have a single-layer structure or a multilayer structure including Al, Ag, Cu, Pb, Mo, Ti or an alloy thereof. For example, the anode132is formed to have a structure in which a transparent conductive film, an opaque conductive film and a transparent conductive film are sequentially laminated.

The light emitting stack134is formed by laminating a hole transport layer, a light emitting layer, and an electron transport layer on the anode132in this order or in reverse order.

The cathode136is formed on upper surfaces and side surfaces of the light emitting stack134and the bank138, to face the anode132under the condition that the light emitting stack134is interposed between the anode132and the cathode136.

An encapsulation unit140is formed to prevent penetration of external moisture or oxygen into the light emitting element130, which is weak against moisture or oxygen. To this end, the encapsulation unit140includes a plurality of inorganic encapsulation layers142and146, and an organic encapsulation layer144disposed between adjacent ones of the inorganic encapsulation layers142and146. The inorganic encapsulation layer146is disposed at an uppermost position of the encapsulation unit140. In this case, the encapsulation unit140includes at least one inorganic encapsulation layer142or146and at least one organic layer144. The following description will be given in conjunction with an example in which the encapsulation unit140has a structure including a first inorganic encapsulation layer142and a second inorganic encapsulation layer146, and one organic encapsulation layer144disposed between the first and second inorganic encapsulation layers142and146in accordance with the present disclosure.

The first inorganic encapsulation layer142is formed on the substrate101formed with the cathode136such that the first inorganic encapsulation layer142is disposed closest to the light emitting element130. The first inorganic encapsulation layer142is made of an inorganic insulating material capable of being deposited at low temperature, for example, silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiON) or aluminum oxide (Al2O3). As such, the inorganic encapsulation layer142may be deposited in a low-temperature atmosphere. Accordingly, it may be possible to prevent damage to the light emitting stack134, which is weak in a high-temperature atmosphere during deposition of the first inorganic encapsulation layer142.

The second inorganic encapsulation layer146is formed to cover upper and side surfaces of the organic encapsulation layer144and an exposed upper surface of the first inorganic encapsulation layer142not covered by the organic encapsulation layer144. As a result, upper and lower surfaces of the organic encapsulation layer144are sealed by the first and second inorganic encapsulation layers142and146and, as such, it may be possible to minimize or prevent penetration of external moisture or oxygen into the organic encapsulation layer144or penetration of moisture or oxygen present within the organic encapsulation layer144into the light emitting element130. The second inorganic encapsulation layer146is made of an inorganic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiON) or aluminum oxide (Al2O3).

The organic encapsulation layer144serves as a buffer to buffer stress generated among layers during bending of the organic light emitting display device while enhancing planarization performance. In addition, the organic encapsulation layer144is formed to have a greater thickness than the inorganic encapsulation layers142and146, in order to prevent formation of cracks or pin holes caused by foreign matter. The organic encapsulation layer144is made of an organic insulating material such as acryl resin, epoxy resin, polyimide, polyethylene, or silicon oxycarbide (SiOC).

Upon formation of the organic encapsulation layer144, an outer dam128and an inner dam108are formed in order to restrict flowability of the organic encapsulation layer144.

As illustrated inFIG. 1, at least one outer dam128may be formed to completely enclose the active area AA where light emitting elements130are disposed or may be formed only in an area between the active area AA and the pad area PDA. When a pad area PDA formed with a plurality of pads122is disposed at one side of the substrate101, the outer dam128is disposed only at one side of the substrate101. On the other hand, when pad areas PDA each formed with a plurality of pads122are disposed at opposite sides of the substrate101, respectively, outer dams128are disposed at the opposite sides of the substrate101, respectively. When plural outer dams128are disposed, the outer dams128are disposed in parallel while being spaced apart from one another by a certain distance. By virtue of such an outer dam128, it may be possible to prevent diffusion of the inorganic encapsulation layer144into the pad area PDA.

At least one inner dam108is disposed to completely enclose a substrate hole120disposed in the hole area HA. When plural inner dams108are disposed, the inner dams108are disposed in parallel while being spaced apart from one another by a certain distance. Such an inner dam108is formed to have a single-layer structure or a multilayer structure including layers108a and108b, similarly to the outer dam128. For example, each of the inner dam108and the outer dam128is formed simultaneously with at least one of the planarization layer104, the bank138or a spacer (not shown), using the same material, and, as such, use of an additional mask process and an increase in costs may be prevented. By virtue of such an inner dam108, the organic encapsulation layer144, which may function as a moisture penetration path, may be prevented from being diffused into the hole area HA.

The bezel area BA is disposed between the hole area HA and the emission areas EA disposed adjacent to the hole area HA. In the bezel area BA, the above-described inner dam108, at least one blocking hole110and a through hole170are disposed.

Each blocking hole110is disposed between each inner dam108and the substrate hole120. The blocking hole110is formed to pass through at least one of the multi-buffer layer112, the active buffer layer114, the gate insulating film116, or the interlayer insulating film102having a multilayer structure disposed between the substrate101and the planarization layer104. In this case, the interlayer insulating film102, which has a multilayer structure, includes layers of different inorganic insulating materials alternately laminated between the gate electrode152and the source and drain electrodes156and158. The following description will be given in conjunction with a structure of the interlayer insulating film102in which a second interlayer insulating film102bis interposed between first and third interlayer insulating film102aand102cwhile being made of a material different from those of the first and third interlayer insulating film102aand102cin accordance with the present disclosure, as illustrated inFIG. 3A or 3B.

When the first and third interlayer insulating films102aand102cin the case ofFIG. 3Aare made of SiNx, the second interlayer insulating film102bmay be made of SiOx. In this case, side surfaces of the second interlayer insulating film102bexposed through the blocking hole110may protrude beyond those of the first and third interlayer insulating films102aand102c.Meanwhile, the active buffer layer114and the gate insulating film116contacting the active layer154are made of the same material as the second interlayer insulating film102b,that is, SiOx, in order to prevent diffusion of hydrogen into the active layer154. As such, side surfaces of the active buffer layer114and the gate insulating film116may also protrude beyond those of the first and third interlayer insulating films102aand102c.

Since the side surfaces of the second interlayer insulating film102bexposed through the blocking hole110protrude beyond those of the first and third interlayer insulating films102aand102c,as described above, the first interlayer insulating film102adisposed beneath the second interlayer insulating film102bincludes an undercut.

When the first and third interlayer insulating films102and102cin the case ofFIG. 3Bare made of SiOx, the second interlayer insulating film102bmay be made of SiNx. In this case, side surfaces of the first and third interlayer insulating films102aand102cexposed through the blocking hole110protrude beyond those of the second interlayer insulating film102b.As such, the second interlayer insulating film102bdisposed beneath the third interlayer insulating film102cmay include an undercut.

By virtue of the undercut of the first interlayer insulating film102aillustrated inFIG. 3Aor the undercut of the second interlayer insulating film102billustrated inFIG. 3B, the light emitting stack134and the cathode136are formed to be disconnected without having continuance within the blocking hole110. Accordingly, even when external moisture penetrates along the light emitting stack134disposed near the hole area HA, it may be possible to prevent or delay introduction of the penetrated moisture into the emission area EA by the blocking hole110. In addition, even when static electricity is introduced along the cathode136disposed near the hole area HA, diffusion of the introduced static electricity into the emission area EA may be prevented by the blocking hole110. Furthermore, the blocking hole110exhibits great hardness, as compared to organic insulating materials, and, as such, it may be possible to prevent propagation of cracks into the emission area EA through removal of the inorganic insulating layers114,116, and102, which may easily generate cracks when subjected to bending stress.

Meanwhile, in the case illustrated inFIG. 3A, the side surfaces of the second interlayer insulating film102b(upper inorganic insulating film) protrude beyond those of the first interlayer insulating film102a(lower inorganic insulating film) by about 0.1 to 0.2 μm. On the other hand, in the case illustrated inFIG. 3B, the side surfaces of the third interlayer insulating film102c(upper inorganic insulating film) protrude beyond those of the second interlayer insulating film102b(lower inorganic insulating film) by about 0.1 to 0.2 μm.

When the side surfaces of the upper inorganic insulating film protrude beyond those of the lower inorganic insulating film by less than 0.1 μm, the light emitting stack134and the cathode136are formed without being disconnected. As a result, moisture, static electricity, and cracks may be diffused into the emission area EA along the light emitting stack134.

On the other hand, when the side surfaces of the upper inorganic insulating film protrude beyond those of the lower inorganic insulating film by more than 0.2 μm, the lower inorganic insulating film cannot withstand the weight of the upper inorganic insulating film and, as such, protruding portions of the upper inorganic insulating film may collapse.

An inorganic cover layer148made of an inorganic insulating material is formed on the encapsulation unit140. The inorganic cover layer148seals interfaces among the plural thin films112,114,116,102,142,146,136, and134exposed through the through hole170and, as such, it may be possible to minimize or prevent penetration of external moisture or oxygen into the interfaces of the plural thin films.

The through hole170is formed to pass through a plurality of thin film layers disposed between the substrate101and the inorganic cover layer148. For example, the through hole170is formed to pass through portions of the inorganic insulating layers112,114,116, and102, the light emitting stack134, the cathode136, and the inorganic encapsulation layers142and146disposed in the hole area HA and an area disposed therearound, thereby exposing an upper surface of the substrate101. As the portions of the inorganic insulating layers112,114,116, and102, the light emitting stack134, the cathode136, and the inorganic encapsulation layers142and146are removed by virtue of the through hole170, simplification of a laser trimming process may be achieved.

Since the hole area HA is disposed within the active area AA, the hole area HA may be surrounded by a plurality of subpixels SP disposed in the active area AA. Although the hole area HA is illustrated as having a circular shape, the hole area HA may be formed to have a polygonal shape or an oval shape.

An electronic component including a camera, a speaker, a flash light source or a biometric sensor such as a fingerprint sensor is disposed in the hole area HA. The following description will be given in conjunction with an example in which a camera module160is disposed in the hole area HA in accordance with the present disclosure, as illustrated inFIG. 4.

The camera module160includes a camera lens164and a camera driver162.

The camera driver162is disposed at a lower surface of the substrate101, which is included in a display panel, such that the camera driver162is connected to the camera lens164.

The camera lens164is disposed within the substrate hole120extending from a lower thin film layer (for example, the substrate101or a back plate) disposed at a lowermost position of the active area AA to an upper thin film layer (for example, a polarization plate166) disposed at an uppermost position of the active area AA. Accordingly, the camera lens164is disposed to face a cover glass168. In this case, the substrate hole120is disposed to overlap with the through hole170while having a smaller width than the through hole170. The substrate hole120may be disposed to pass through the substrate101, the inorganic insulating layer148, and the polarization plate166, or may be disposed to pass through the substrate101and the polarization plate166.

As the camera module160is disposed within the active area AA, it may be possible to minimize the bezel area, which is a non-display area of the display device.

FIGS. 5A to 5Care cross-sectional views explaining a method for forming each blocking hole110illustrated inFIG. 3Aaccording to an embodiment of the present disclosure.

As illustrated inFIG. 5A, the substrate101, on which the multi-buffer layer112, the active buffer layer114, the gate insulating film116and the interlayer insulating film102having a multilayer structure are sequentially laminated, is first prepared. Thereafter, a hard mask layer is formed over the entire upper surface of an uppermost layer of the interlayer insulating film102having a multilayer structure. In this case, the hard mask layer is formed to have a single-layer structure or a multilayer structure, using at least one of ITO, MoTi, Mo, or Ti. A photoresist pattern178is then formed on the hard mask layer through a photolithography process using a photomask. A hard mask pattern180is subsequently formed through an etching process using the photoresist pattern178as a mask.

Next, the interlayer insulating film102, the gate insulating film116and the active buffer layer114are primarily etched through a dry etching process using the hard mask pattern180and the photoresist pattern178as a mask, thereby forming each blocking hole110, as illustrated inFIG. 5B. In this case, the first and third interlayer insulating films102aand102cexhibit higher etching rates than the second interlayer insulating film102band, as such, side surfaces of the second interlayer insulating film102bprotrude beyond those of the first and third interlayer insulating films102aand102c.In addition, the photoresist pattern178is removed while reacting with dry etching gas during the dry etching process because the dry etching process is carried out for a long time due to a great depth of each blocking hole110.

Thereafter, the first and third interlayer insulating films102aand102care selectively etched through a wet etching process using the hard mask pattern180as a mask. As a result, the side surfaces of the second interlayer insulating film102bfurther protrude beyond those of the first and third interlayer insulating films102aand102c,as illustrated inFIG. 5C.

Subsequently, the hard mask pattern180is removed through an etching process.

Meanwhile, although formation of each blocking hole110has been described as being carried out through a dry etching process and a wet etching process in the case ofFIGS. 5A to 5C, the blocking hole110may be formed only through a dry etching process without using a wet etching process. That is, after primary dry etching of the first to third interlayer insulating films102a,102b,and102c,the gate insulating film116and the active buffer layer114, the first and third interlayer insulating films102aand102c(or the second interlayer insulating film102b) made of SiNxare selectively secondarily dry-etched. Selective secondary dry etching of the gate insulating film116, the active buffer layer114and the first and third interlayer insulating films102aand102c(or the second interlayer insulating film102b) made of SiNxis achieved by adjusting power used in the secondary dry etching to be lower than that of the primary dry etching.

Meanwhile, each blocking hole110may be formed before or after formation of pixel contact holes126or before or after formation of the source and drain contact holes124S and124D.

FIG. 6is a cross-sectional view illustrating a display device according to a second embodiment of the present disclosure.

The display device illustrated inFIG. 6includes the same constituent elements as those of the display device illustrated inFIG. 2, except that a hard mask pattern180is further included. Accordingly, no detailed description will be given of the same constituent elements for the sake of brevity.

The hard mask pattern180is formed on the uppermost interlayer insulating film102cof the interlayer insulating film102having a multilayer structure, using one of ITO, MoTi, Mo, and Ti, to have a single-layer structure or a multilayer structure. Although the hard mask pattern180is removed in the above-described process ofFIGS. 5A-5C, the hard mask pattern180is left on the substrate101without being removed in this case. For example, a photoresist pattern having a multi-step structure may be formed through a photolithography process using a half-tone mask, and the hard mask pattern180may then be selectively left in an area around each blocking hole110through an etching process using the photoresist pattern having the multi-step structure. Otherwise, the hard mask pattern180may be selectively left in the area around each blocking hole110through an additional mask process after execution of the wet etching process illustrated inFIG. 5C.

In this case, as illustrated inFIG. 7, side surfaces of the hard mask pattern180exposed through each blocking hole110protrude beyond those of the uppermost interlayer insulating film, that is, the third interlayer insulating film102c,by about 0.1 to 0.2 μm. Accordingly, the uppermost interlayer insulating film disposed beneath the hard mask pattern180, that is, the third interlayer insulating film102c,includes a first undercut.

Meanwhile, the first and third interlayer insulating films102aand102care made of materials different from that of the second interlayer insulating film102b.For example, the first and third interlayer insulating films102aand102care made of SiNx, whereas the second interlayer insulating film102bis made of SiOx. In this case, side surfaces of the second interlayer insulating film102bexposed through each blocking hole110protrude beyond those of the first and third interlayer insulating films102aand102c.Accordingly, the first interlayer insulating film102adisposed beneath the second interlayer insulating film102bincludes a second undercut because the side surfaces of the second interlayer insulating film102bexposed through each blocking hole110protrude beyond those of the first and third interlayer insulating films102aand102cby about 0.1 to 0.2 μm.

By virtue of the undercuts of the first and third interlayer insulating films102aand102c,the light emitting stack134and the cathode136are formed to be disconnected without having continuance in each blocking hole110. In this case, since the interlayer insulating film102illustrated inFIG. 6includes the first and second undercuts, it may be possible to reduce failure of disconnection of the light emitting stack134, as compared to the interlayer insulating film102ofFIG. 2including one undercut. As a result, even when external moisture penetrates along the light emitting stack134disposed near the hole area HA, it may be possible to more efficiently prevent or delay introduction of the penetrated moisture into the emission area EA by the blocking hole110. In addition, even when static electricity is introduced along the cathode136disposed near the hole area HA, diffusion of the introduced static electricity into the emission area EA may be more efficiently prevented by the blocking hole110. Furthermore, the blocking hole110exhibits great hardness, as compared to organic insulating materials, and, as such, it may be possible to prevent propagation of cracks into the emission area EA through removal of the inorganic insulating layers114,116and102, which may easily generate cracks when subjected to bending stress.

FIG. 8is a cross-sectional view illustrating a display device according to a third embodiment of the present disclosure.

The display device illustrated inFIG. 8includes the same constituent elements as those of the display device illustrated inFIG. 2, except that a passivation film118is further included. Accordingly, no detailed description will be given of the same constituent elements for the sake of brevity.

The passivation film118is formed between the thin film transistor (TD)150and the anode132. That is, the passivation film118is disposed on the uppermost interlayer insulating film102cof the interlayer insulating film102having a multilayer structure. The passivation film118is made of a material different from that of the third interlayer insulating film102c,which is the uppermost interlayer insulating film. For example, the passivation film118and the second interlayer insulating film102bare made of SiOx, whereas the first and third interlayer insulating films102aand102care made of SiNx. Accordingly, side surfaces of the passivation film118exposed through each blocking hole110protrude beyond those of the third interlayer insulating film102c,as illustrated inFIG. 9, and, as such, the third interlayer insulating film102cdisposed beneath the passivation film118includes a first undercut. In addition, side surfaces of the second interlayer insulating film102bexposed through each blocking hole110protrude beyond those of the first and third interlayer insulating films102aand102cand, as such, the first interlayer insulating film102adisposed beneath the second interlayer insulating film102bincludes a second undercut.

By virtue of the undercuts of the first and third interlayer insulating films102aand102c,the light emitting stack134and the cathode136are formed to be disconnected without having continuance in each blocking hole110. In this case, since the interlayer insulating film102illustrated inFIG. 8includes the first and second undercuts, it may be possible to reduce failure of disconnection of the light emitting stack134, as compared to the interlayer insulating film102ofFIG. 2including one undercut. As a result, even when external moisture penetrates along the light emitting stack134disposed near the hole area HA, it may be possible to more efficiently prevent or delay introduction of the penetrated moisture into the emission area EA by the blocking hole110. In addition, even when static electricity is introduced along the cathode136disposed near the hole area HA, diffusion of the introduced static electricity into the emission area EA may be more efficiently prevented by the blocking hole110. Furthermore, the blocking hole110exhibits great hardness, as compared to organic insulating materials, and, as such, it may be possible to prevent propagation of cracks into the emission area EA through removal of the inorganic insulating layers114,116, and102, which may easily generate cracks when subjected to bending stress.

Meanwhile, although the through hole170has been described as being formed to pass through the inorganic insulating layers112,114,116and102, the light emitting stack134, the cathode136, and the inorganic encapsulation layers142and146disposed between the substrate101and the inorganic cover layer148in accordance with the present disclosure, as illustrated inFIG. 2, the through hole170may be formed to extend only to the first and second inorganic encapsulation layers142and146and the multi-buffer layer112, as illustrated inFIG. 10. That is, since each blocking hole110is formed to pass through portions of the active buffer layer114, the gate insulating film116and the interlayer insulating film102disposed in the hole area HA and the area disposed therearound, the through hole170may be formed to pass through only the first and second inorganic encapsulation layers142and146and the multi-buffer layer112. In this case, side surfaces of the second interlayer insulating film102bexposed through the through hole170protrude beyond side surfaces of the first and third interlayer insulating films102aand102c,or the side surfaces of the first and third interlayer insulating films102aand102cprotrude beyond the side surfaces of the second interlayer insulating film102b.

Since only the first and second inorganic encapsulation layers142and146and the multi-buffer layer112are selectively etched during formation of the through hole170, as described above, it may be possible to simplify the process of forming the through hole170.

As apparent from the above description, the present disclosure provides the following effects.

As the substrate hole, in which a camera module is fitted, is disposed within the active area in accordance with the present invention, it may be possible to minimize the bezel area, which is a non-display area of the display device.

In addition, in accordance with the present disclosure, side surfaces of the upper inorganic insulating film exposed through each blocking hole protrude beyond those of the lower inorganic insulating film, the light emitting stack is disconnected without having continuance in the blocking hole. Accordingly, it may be possible to prevent or delay introduction of external moisture into the emission area by the blocking hole.