Patent ID: 12225757

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Referring toFIGS.1and2, a display device is illustrated. The display device includes an active area AA and a pad area PDA.

As illustrated inFIGS.1and2, the pad area PDA is formed with a plurality of pads122to supply drive signals to a plurality of signal lines106disposed in the active area AA, respectively. 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 (VS S) supply line.

Each pad122is made of the same material as a corresponding one of the signal lines106each including at least one of the scan line SL, the data line DL, the high-voltage (VDD) supply line or the low-voltage (VS S) supply line disposed in the active area AA, while being disposed on the same layer as the corresponding signal line106. Each pad122is exposed through a pad contact hole124passing or extending through an organic cover layer112, to contact a signal transmission film (not shown) connected to a driving circuit (not shown).

The active area AA includes pixel areas PA, a bezel area BA and a hole area HA.

Unit pixels, each of which includes a light emitting element130, are disposed in the pixel areas PA, 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.

The light emitting element130includes an anode132connected to the drain electrode of the driving transistor TD, 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 disposed on a planarization layer104without being covered by a bank138such that 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 first and second inorganic encapsulation layers142and146, and one organic encapsulation layer144disposed between the first and second inorganic encapsulation layers142and146.

The first inorganic encapsulation layer142is formed on the substrate101formed with the cathode136such that the first inorganic encapsulation layer142is disposed most adjacent 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. 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 dam118and an inner dam108are formed in order to restrict flowability of the organic encapsulation layer144.

As illustrated inFIG.1, at least one outer dam118may be formed to completely surround the active area AA where light emitting elements130are disposed or may be formed in an area between the active area AA and the pad area PDA. When a pad area PDA formed with pad electrodes designated by reference numeral “122” is disposed at one side of the substrate101, the outer dam128is disposed at one side of the substrate101. On the other hand, when pad areas PDA each formed with pad electrodes122are disposed at opposite sides of the substrate101, respectively, outer dams118are 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 organic encapsulation layer144into the pad area PDA.

At least one inner dam108is disposed to completely surround a second through 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 layers108aand108b, similarly to the outer dam118. For example, each of the inner dam108and the outer dam118is formed concurrently with at least one of the planarization layer104, the bank128or 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 BA is disposed between the hole area HA and the pixel areas PA disposed adjacent to the hole area HA. In the bezel area BA, the above-described inner dam108, at least one blocking groove110, the organic cover layer112, an inorganic cover layer114and a first through hole170are disposed.

The blocking groove110is formed to pass through an inorganic insulating layer102including at least one of a multi-buffer layer, an active buffer layer, a gate insulating film, an interlayer insulating film or a passivation film disposed between the substrate101and the planarization layer104. In this case, side surfaces of the inorganic insulating layer102exposed through the blocking groove110are formed to have a reversed taper shape such that the side surfaces form an acute angle or a right angle with respect to a lower surface of the inorganic insulating layer102exposed through the blocking groove110. By virtue of such a blocking groove110, each of the light emitting stack134and the cathode136is disconnected without having continuance during formation thereof. Accordingly, even when external moisture penetrates along the light emitting stack134disposed near the hole area HA, introduction of the penetrated moisture into the pixel area PA may be prevented or delayed by the blocking groove110. In addition, even when static electricity is introduced along the cathode136disposed near the hole area HA, diffusion of the introduced static electricity into the pixel area PA may be prevented by the blocking groove110. Furthermore, the blocking groove110exhibits 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 layer102, which may easily generate cracks when subjected to bending stress.

The organic cover layer112is formed on the encapsulation unit140, using a photosensitive insulating material, and, as such, a separate stripping process is unnecessary upon formation of the organic cover layer112. For example, the organic cover layer112is made of a photoacryl material.

As illustrated inFIG.2, the organic cover layer112is disposed on the inorganic encapsulation layer146such that side surfaces of plural thin film layers exposed through the first through hole170are maintained in an exposed state. For example, the plural thin film layers include at least one of the inorganic insulating layer102, the light emitting stack134, the cathode136or the inorganic encapsulation layer142or146. In this case, the organic cover layer112does not contact the light emitting stack134and, as such, it may be possible to prevent penetration of moisture into the light emitting stack134via the organic cover layer112.

In addition, the organic cover layer112is disposed on side and upper surfaces of the inorganic encapsulation layer146, to cover side surfaces of the plural thin film layers102,134,136,142and146exposed through the first through hole170, as illustrated inFIG.3A. In this case, the organic cover layer112illustrated inFIG.3Aprotects the light emitting stack134because the organic cover layer112is formed to cover side surfaces of the light emitting stack134.

As illustrated inFIG.3A, the organic cover layer112may be formed in areas PA, BA and PDA except for the hole area HA, or may be formed in the bezel area BA and the pad area PDA. In this case, the organic cover layer112illustrated inFIGS.2,3A and3Bis formed to enclose the hole area HA and, as such, overlaps with at least one of the blocking groove110or the inner dam108.

The inorganic cover layer114is formed on the organic cover layer112, using an inorganic insulating material. The inorganic cover layer114is disposed on upper and side surfaces of the organic cover layer112disposed in the active area AA. The organic cover layer112and interfaces among the thin films112,146,142,136,134,102and101are sealed by the inorganic cover layer114and, as such, it may be possible to minimize or prevent penetration of external moisture or oxygen into the organic cover layer112and the interfaces.

The first through hole170is formed not to overlap with the organic cover layer112while passing or extending through the plural thin film layers disposed between the substrate101and the organic cover layer112. For example, the first through hole170is formed to pass through portions of the inorganic insulating layer102, the light emitting stack134, the cathode136and the inorganic encapsulation layers142and146disposed in the hole area HA and the area disposed therearound, thereby exposing the upper surface of the substrate101. In this case, the first through hole170is formed through a dry etching process using the organic cover layer112as a mask. By virtue of the first through hole170, portions of the inorganic insulating layer102, the light emitting stack134, the inorganic encapsulation layers142and146, etc., disposed in the hole area HA are removed and, as such, 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, 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 second through hole120, which extends 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 second through hole120is disposed to overlap with the first through hole170while having a smaller width than the first through hole170. The second through hole120may be disposed to pass through the substrate101, the inorganic cover layer114and 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 to5Eare cross-sectional views explaining a method for manufacturing an organic light emitting display device according to a first embodiment of the present disclosure, that is, the organic light emitting display device illustrated inFIG.2.

In detail, the multi-buffer layer and the active buffer layer included in the organic insulating layer102are formed on the substrate101, as illustrated inFIG.5A. Here, the substrate101is made of a plastic material having flexibility, to be bendable. For example, the substrate101is made of polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyethersulfone (PES), polyarylate (PAR), polysulfone (PSF), or cyclic-olefin copolymer (COC). The multi-buffer layer may be formed over the entirety of the substrate101. The multi-buffer layer may provide an environment capable of more stably realizing thin film formation while enabling more effective execution of various processes before execution of a main display panel fabrication process. The multi-buffer layer may include one of a first layer including SiO2and a second layer including SiNx, or may be formed to have a structure in which the first layer and the second layer are sequentially laminated in this order or reverse order. The active buffer layer is an inorganic insulating layer enabling more stable formation of an active layer of thin film transistors (not shown), and may include SiO2.

Thereafter, the active layer is formed on the active buffer layer through a photolithography process and an etching process. The gate insulating film, which is included in the inorganic insulating layer102, is then formed over the active layer. The gate electrode is then formed on the gate insulating film through a photolithography process and an etching process. Subsequently, the interlayer insulating film, which is included in the inorganic insulating layer102is formed. The interlayer insulating film is then patterned through a photolithography process and an etching process, thereby forming source and drain contact holes (not shown), through which the active layer is exposed. Thereafter, the interlayer insulating film, the gate insulating film and the active buffer layer are patterned through a photolithography process and an etching process, thereby forming the blocking groove110, through which the upper surface of the multi-buffer layer is exposed. At this time, a portion of the multi-buffer layer may also be patterned in accordance with the etching process and, as such, a side surface of the multi-buffer layer may be exposed through the blocking groove110.

Subsequently, the source and drain electrodes (not shown), the signal lines106and the pad electrodes112are formed through a photolithography process and an etching process. The planarization layer104and the anode132are then sequentially formed through a photolithography process and an etching process. Subsequently, the bank138, the inner dam108and the outer dam128are concurrently formed through a photolithography process and an etching process using the same mask.

Thereafter, the organic light emitting layer134and the cathode136are sequentially formed on the substrate101formed with the bank138through a deposition process using a shadow mask, as illustrated inFIG.5B. In this case, the light emitting stack134and the cathode136are disconnected without having continuance by the blocking groove110. Next, at least one inorganic encapsulation layer (the inorganic encapsulation layers142and146in the illustrated case) and at least one organic encapsulation layer (the organic encapsulation layer144in the illustrated case) are laminated over the cathode136, thereby forming the encapsulation unit140. In this case, the organic encapsulation layer144is formed in an area, except for the hole area HA and the pad area PDA, by virtue of the inner dam108and the outer dam118.

Thereafter, a photosensitive inorganic insulating material is coated over the entire upper surface of the substrate101formed with the encapsulation unit140. The coated photosensitive inorganic insulating material is then patterned through a photolithography process using a halftone mask, thereby forming the organic cover layer112, as illustrated inFIG.5C. In this case, the organic cover layer112is formed not to cover a portion of the uppermost inorganic encapsulation layer145disposed in the hole area HA such that the portion is exposed, while covering upper surfaces of the pad electrodes122.

Thereafter, portions of the inorganic encapsulation layers142and146, the cathode136, the light emitting stack134and the inorganic insulating film102disposed on the substrate101are removed through a dry etching process using the organic cover layer112as a mask, thereby forming the first through hole170, as illustrated inFIG.5D. In this case, the first through hole170is patterned through the dry etching process using the organic cover layer112as a mask and, as such, a separate photoresist pattern is unnecessary. In this regard, a stripping process for removal of such a photoresist pattern is unnecessary. Furthermore, it may be possible to prevent penetration of moisture into interfaces among the plural thin films112,142,146,136,134and102caused by a stripping solution used in a stripping process.

Thereafter, the pad contact holes124are formed by removing portions of the organic cover layer112disposed on the pad electrodes112through an ashing process.

Meanwhile, although the case in which the pad contact holes124and the first through hole170are concurrently formed through a single mask process using a halftone mask has been illustratively described, each pad contact hole124and the first through hole170may be formed through separate mask processes, respectively.

Subsequently, an inorganic insulating material is deposited over the entire upper surface of the substrate101formed with the pad contact holes124and the first through hole170, thereby forming the inorganic cover layer114, as illustrated inFIG.5E. The substrate101, the inorganic cover layer114and the polarization film designated by reference numeral “166” inFIG.4are patterned through a laser trimming process, thereby forming the second through hole120.

As apparent from the above description, in the present disclosure, the first through hole170for preventing continuance of the light emitting stack134is formed through a dry etching process using the organic cover layer112made of a material not requiring a stripping process as a mask. Accordingly, it may be possible to prevent damage to the light emitting stack134caused by a stripping process.

In addition, the second through hole120is formed by removing a desired portion of the substrate101through a laser trimming process after formation of the first through hole170achieved in accordance with removal of the portions of the plural thin film layers disposed in the hole area HA through a dry etching process. Accordingly, portions of the thin films to be removed through the laser trimming process may be minimized and, as such, physical impact generated during the laser trimming process may be minimized.

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

The organic light emitting display device illustrated inFIG.6includes the same constituent elements as those of the organic light emitting display device illustrated inFIG.2, except that a touch sensor is further included. Accordingly, no detailed description will be given of the same constituent elements.

The touch sensor includes a plurality of touch electrodes152, and a plurality of bridges154connecting the touch electrodes152.

The touch electrodes152may be constituted by a transparent conductive film made of ITO or IZO, may be constituted by a mesh metal film having a mesh structure, or may be constituted by a transparent conductive film as described above and a mesh metal film disposed over or beneath the transparent conductive film. Here, the mesh metal film is formed to have a mesh structure, using at least one conductive layer made of Ti, Al, Mo, MoTi, Cu, Ta or ITO while exhibiting better conductivity than the transparent conductive film. For example, the mesh metal film may be formed to have a triple-layer structure of Ti/Al/Ti, MoTi/Cu/MoTi, or Ti/Al/Mo.

One of each bridge154and each touch electrode152is disposed on the organic cover layer112, whereas the other of each bridge154and each touch electrode152is disposed on a touch insulating film158. That is, although each touch electrode152and each bridge154illustrated inFIG.6have been described in conjunction with the case in which each touch electrode152is disposed on the touch insulating film158, and each bridge154is disposed on the organic cover layer112, each bridge154may be disposed on the touch insulating film158, and each touch electrode152may be disposed on the organic cover layer112.

The touch insulating film158includes touch contact holes156each electrically connecting corresponding ones of the bridges154and the touch electrodes152. The touch insulating film158is made of the same material as the inorganic cover layer114, to be integrated with the inorganic cover layer114. Upon formation of the touch contact holes156passing or extending through the touch insulating film158, the portion of the inorganic cover layer114disposed in the hole area HA may also be removed. As such, the second through hole120is formed during execution of a laser trimming process such that the second through hole120passes through the substrate101and the polarization plate166. Further a third through hole310may be formed that extends through the touch insulating film158as shown inFIGS.6and7. In this case, it may be possible to prevent generation of cracks in the inorganic cover layer114caused by physical impact generated during execution of the laser trimming process or propagation of the generated cracks into the pixel areas PA. In some embodiments, the third through hole310extending through the touch insulating film158overlaps with the second through hole120from a plan view as shown inFIGS.6and7.

In addition, at least one of the touch buffer film148and the touch insulating film158disposed beneath the touch sensor (152and154) may be made of the same material as the inorganic cover layer114, to be integrated with the inorganic cover layer114, as illustrated inFIG.7. In this case, the inorganic cover layer114may be formed to have a multilayer structure.

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

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

In addition, the through hole, which prevents continuance of the light emitting stack, is formed through an etching process using an organic cover layer made of a material not requiring a stripping process as a mask. Accordingly, it may be possible to prevent damage to the light emitting stack caused by a stripping process.

It will be apparent to those skilled in the art that various modifications and variations can be made to the various embodiments of the present disclosure without departing from the spirit or scope of the present disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

The various embodiments described above can be combined to provide further embodiments.

These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.