KR102203766B1 - Flexible display device and method of fabricating the same - Google Patents

Abstract

The flexible display device and its manufacturing method of the present invention are formed by forming a heat dissipation layer on a flexible substrate with a conductive film having good thermal conductivity properties or forming a heat dissipation hole in a specific position of the flexible substrate under the channel to release heat generated from the channel to the outside. In order to improve driving failure due to internal heat generation during high temperature driving, the method comprising: providing an auxiliary substrate; Forming a flexible substrate divided into a display area on the auxiliary substrate and a gate in panel (GIP) circuit portion outside the display area; Forming a heat dissipation layer on the flexible substrate; Forming a display panel on the flexible substrate on which the heat dissipation layer is formed; And separating the auxiliary substrate from the display panel.

Description

Flexible display device and its manufacturing method {FLEXIBLE DISPLAY DEVICE AND METHOD OF FABRICATING THE SAME}

The present invention relates to a flexible display device and a method of manufacturing the same, and more particularly, to a flexible display device implemented on a flexible substrate such as plastic and a method of manufacturing the same.

In the recent information society, the importance of display devices as a transmission medium for visual information has been further emphasized, and in order to occupy an important position in the future, it is necessary to meet requirements such as low power consumption, thinner weight, lighter weight and high quality.

The display device includes a cathode ray tube (CRT), an electroluminescence device (EL), a light emitting diode (LED), a vacuum fluorescent display (VFD), Light-emitting type and liquid crystal such as organic light emitting device (OLED), field emission display (FED), plasma display panel (PDP), electrophoresis display device, etc. It can be classified into a non-luminous type that does not emit light itself, such as a liquid crystal display (LCD).

Meanwhile, a flexible display device that is not damaged even when the display device is folded or rolled in is expected to emerge as a new technology in the display device field. Currently, various obstacles exist in the implementation of flexible displays, but with the development of technology, thin film transistor liquid crystal displays, organic light emitting displays, or electrophoretic displays will become mainstream.

Hereinafter, a flexible display device will be described in detail with reference to the drawings.

1A and 1B are photographs illustrating a general flexible display device as an example.

A flexible display device is called a scroll display device. As shown in the drawing, it is implemented on a thin substrate such as plastic so that it is not damaged even when folded or rolled like paper, and is one of the next generation display devices. Currently, it can be made as thin as 1mm or less. A liquid crystal display device and an organic light emitting display device are promising.

A liquid crystal display is a device that expresses an image by using the optical anisotropy of liquid crystals. It has excellent visibility compared to conventional CRTs, and its average power consumption is smaller than that of CRTs of the same screen size, and therefore, it has less heat generation. It is in the spotlight as a display device.

Organic light-emitting display devices have good visibility even in dark places or when external light comes in because the device itself emits light, and its response speed, which is an important criterion for determining the performance of a mobile display device, is fast among existing display devices. You can implement a video. In addition, since the organic light-emitting display device has an ultra-thin design, various mobile devices such as mobile phones can be made slim.

In order to implement such a flexible display device, it is necessary to secure the flexibility of the substrate, and now, to secure the flexibility of the substrate, a plastic flexible substrate is used instead of the existing glass substrate.

In order to implement a flexible display device as described above, a flexible substrate such as a plastic substrate must be used. In general, the plastic substrate is attached to a glass substrate using an adhesive and the processes are performed in order to transport and process the flexible substrate. However, the adhesion process is complicated, and there is a disadvantage in that the occurrence of defects and productivity decrease due to the progress of a number of lamination processes.

Accordingly, recently, a sacrificial layer made of amorphous silicon is interposed between the plastic substrate and the glass substrate, followed by processes to form a display panel, and to separate the glass substrate from the plastic substrate by applying laser release. Are doing.

When the manufactured flexible display device is driven in a high-temperature environment, heat is generated in the channel of the active layer. At this time, in the case of the conventional flexible display device, heat cannot be radiated to the outside, so the temperature in the channel continues to increase, resulting in device characteristics. This fluctuation causes defects such as poor driving and screen abnormalities.

This is because polyimide, which is used as a substrate of a flexible display device, has low thermal conductivity, and thus cannot effectively dissipate heat generated from a channel to the outside.

An object of the present invention is to solve the above-described problem, and to provide a flexible display device and a method of manufacturing the same to improve driving failure due to internal heat generation during high-temperature driving.

In addition, other objects and features of the present invention will be described in the configuration and claims of the invention to be described later.

In order to achieve the above object, a flexible display device according to an exemplary embodiment of the present invention includes: a flexible substrate divided into a display area and a gate in panel (GIP) circuit part outside the display area; A heat dissipation layer formed of a conductive film of copper, aluminum or ITO on the flexible substrate; A buffer layer formed on the flexible substrate on which the heat dissipation layer is formed; And a TFT formed on the flexible substrate on which the buffer layer is formed and including an active layer.

In this case, the heat dissipation layer may have a thickness of 500 Å to 1000 Å.

The heat dissipation layer may be formed on the GIP circuit part and/or the flexible substrate in the display area.

According to another exemplary embodiment of the present invention, a flexible display device includes: a flexible substrate divided into a display area and a GIP circuit unit outside the display area; A TFT formed on the flexible substrate and including an active layer; And a heat dissipation hole formed in the flexible substrate in the region where the active layer is located to dissipate heat generated from the channel of the active layer to the outside.

In this case, the heat dissipation hole may be formed in the flexible substrate with a size corresponding to or larger than that of the active layer thereon.

The heat dissipation hole may be formed not only on the flexible substrate of the display area but also on the flexible substrate of the GIP circuit.

A method of manufacturing a flexible display device according to an embodiment of the present invention includes the steps of providing an auxiliary substrate; Forming a flexible substrate divided into a display area and a GIP circuit portion outside the auxiliary substrate; Forming a heat dissipation layer on the flexible substrate; Forming a display panel on the flexible substrate on which the heat dissipation layer is formed; And separating the auxiliary substrate from the display panel.

In this case, after the sacrificial layer is formed on the surface of the auxiliary substrate, a flexible substrate may be formed on the auxiliary substrate on which the sacrificial layer is formed.

In this case, after the display panel is formed on the flexible substrate, the sacrificial layer may be removed by irradiating a laser.

The heat dissipation layer may be formed of a conductive film of copper, aluminum or ITO.

The heat dissipation layer may be formed on the flexible substrate of the GIP circuit part and/or the display area.

According to another embodiment of the present invention, a method of manufacturing a flexible display device includes: providing an auxiliary substrate; Forming a flexible substrate divided into a display area and a GIP circuit portion outside the auxiliary substrate; Forming a display panel on the flexible substrate; Separating the auxiliary substrate from the display panel; And forming a heat dissipation hole in the flexible substrate from which the auxiliary substrate is separated.

In this case, after the sacrificial layer is formed on the surface of the auxiliary substrate, a flexible substrate may be formed on the auxiliary substrate on which the sacrificial layer is formed.

In this case, after the display panel is formed on the flexible substrate, the sacrificial layer may be removed by irradiating a laser.

The heat dissipation hole may be formed in the flexible substrate in a region where the active layer is located.

In this case, the heat dissipation hole may be formed in the flexible substrate with a size corresponding to or larger than that of the active layer thereon.

In this case, the heat dissipation hole may be formed not only on the flexible substrate of the display area but also on the flexible substrate of the GIP circuit.

As described above, in the flexible display device and its manufacturing method according to an embodiment of the present invention, a heat dissipation layer is formed on the flexible substrate with a conductive film having good heat conduction properties, or a heat dissipation hole is formed at a specific position of the flexible substrate under the channel. Thus, the heat generated from the channel is released to the outside, thereby providing an effect of improving driving failure due to internal heat generation during high temperature driving.

1A and 1B are photographs illustrating a general flexible display device as an example.
2 is a diagram for explaining the principle of light emission of an organic light emitting diode.
3 is a perspective view schematically showing the structure of a flexible display device according to a first embodiment of the present invention.
4 is a perspective view exemplarily showing another structure of the flexible display device according to the first embodiment of the present invention.
5 is a cross-sectional view schematically showing a part of a display area in the flexible display device according to the first embodiment of the present invention.
6 is a cross-sectional view illustrating a structure of a flexible display device according to a first embodiment of the present invention.
7 is a flowchart sequentially showing a method of manufacturing a flexible display device according to the first embodiment of the present invention.
8A to 8G are perspective views sequentially showing a manufacturing process of the flexible display device according to the first embodiment of the present invention.
9 is a cross-sectional view schematically illustrating a part of a display area in a flexible display device according to a second exemplary embodiment of the present invention.
10 is a flowchart sequentially showing a method of manufacturing a flexible display device according to a second embodiment of the present invention.

Hereinafter, preferred embodiments of a flexible display device and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity of description.

When an element or layer is another element or referred to as “on” or “on”, it includes both the case where another layer or other element is interposed in the middle as well as directly above the other element or layer. do. On the other hand, when a device is referred to as "directly on" or "directly on", it indicates that there is no intervening other device or layer in between.

The terms "below, beneath", "lower", "above", "upper", which are spatially relative terms, refer to one element or component as shown in the drawing. It can be used to easily describe the correlation between the and other devices or components. Spatially relative terms should be understood as terms including different directions of the device during use or operation in addition to the directions shown in the drawings. For example, if an element shown in the figure is turned over, an element described as “below” or “beneath” of another element may be placed “above” another element. Accordingly, the exemplary term “below” may include both directions below and above.

The terms used in the present specification are for describing exemplary embodiments, and therefore, are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used in the specification, "comprise" and/or "comprising" refers to the presence of one or more other components, steps, actions and/or elements, and/or elements, steps, actions and/or elements mentioned. Or does not exclude additions.

A flexible display device is one of the next-generation display devices because it is implemented on a thin substrate such as plastic and is not damaged even when folded or rolled like paper. Currently, a liquid crystal display device and an organic light emitting display device are promising.

Hereinafter, a case in which an organic light-emitting display device is applied as a flexible display device is described as an example, but the present invention is not limited thereto.

2 is a diagram for explaining the principle of light emission of an organic light-emitting diode.

As shown in FIG. 2, the organic light emitting display device includes an organic light emitting diode. The organic light emitting diode includes a plurality of organic compound layers 130a, 130b, 130c, 130d, and 130e formed between an anode 118 as a pixel electrode and a cathode 128 as a common electrode.

At this time, the organic compound layers 130a, 130b, 130c, 130d, and 130e are a hole injection layer 130a, a hole transport layer 130b, an emission layer 130c, and electrons. It includes an electron transport layer (130d) and an electron injection layer (electron injection layer) (130e).

When a driving voltage is applied to the anode 118 and the cathode 128, holes passing through the hole transport layer 130b and electrons passing through the electron transport layer 130d are moved to the emission layer 130c to form excitons, As a result, the emission layer 130c emits visible light.

The organic light-emitting display device displays an image by arranging pixels having the organic light-emitting diodes of the above-described structure in a matrix form and selectively controlling the pixels with a data voltage and a scan voltage.

The organic light emitting display device is divided into a passive matrix display device or an active matrix display device using a TFT as a switching device. Among them, the active matrix method selects a pixel by selectively turning on a TFT, which is an active element, and maintains light emission of the pixel with a voltage maintained by a storage capacitor.

The pixels of the active matrix type organic light emitting display device include an organic light emitting diode, a data line and a gate line crossing each other, a switching TFT, a driving TFT, and a storage capacitor.

The switching TFT is turned on in response to a scan pulse from a gate line to conduct a current path between its source electrode and a drain electrode. During the on-time period of the switching TFT, the data voltage from the data line is applied to the gate electrode and the storage capacitor of the driving TFT via the source electrode and the drain electrode of the switching TFT.

The driving TFT controls the current flowing through the organic light emitting diode according to the data voltage applied to its gate electrode. In addition, the storage capacitor stores a voltage between the data voltage and the low-potential power supply voltage, and then keeps the voltage constant for one frame period.

3 is a perspective view exemplarily showing the structure of a flexible display device according to a first embodiment of the present invention, and shows an example of a flexible organic light emitting display device in a state in which a flexible circuit board is fastened to a pad region.

4 is a perspective view illustrating another structure of the flexible display device according to the first embodiment of the present invention.

5 is a cross-sectional view schematically illustrating a part of a display area in the flexible display device according to the first embodiment of the present invention.

6 is a cross-sectional view illustrating a structure of a flexible display device according to a first embodiment of the present invention.

In this case, FIG. 5 shows, for example, one subpixel including a TFT portion and a capacitor formation portion of a top emission type organic light emitting display device using a coplanar-structured TFT. However, the present invention is not limited to the structure and light emission method of the TFT.

3 or 4, the flexible organic light emitting display device according to the first embodiment of the present invention includes a panel assembly 100 that displays a large image and a flexible circuit board 106 connected to the panel assembly 100. ).

The panel assembly 100 includes a TFT substrate 110 in which an active area AA and a pad area are defined, and an encapsulation layer formed on the TFT substrate 110 while covering the display area AA. layer) 120.

In this case, the pad area may be exposed without being covered by the encapsulation layer 120.

As the TFT substrate 110 on which the TFT is formed, a polyimide substrate may be applied as a base substrate (not shown), and a back plate 105 may be attached to the rear surface thereof.

In addition, a polarizing plate (not shown) for preventing reflection of light incident from the outside may be attached on the encapsulation layer 120.

At this time, although not shown, sub-pixels are arranged in a matrix form in the display area AA of the TFT substrate 110, and the sub-pixels are driven in the circuit part CA outside the display area AA. Drive elements and other parts such as scan driver and data driver for the purpose are located.

The circuit unit CA is a gate-in panel (GIP) method in which the scan driver is directly mounted on the TFT substrate 110 using a TFT in accordance with the demand for reduction of bezel and cost reduction of a high-resolution model. Can be applied.

In this case, the flexible display device according to the first embodiment of the present invention is made of a conductive film such as copper, aluminum, ITO having good heat conduction properties on the polyimide substrate of the GIP circuit unit CA and/or the display area AA. It is characterized in that the heat dissipation layers 140 ′ and 140 ″ are formed, and the heat dissipation layers 140 ′ and 140 ″ dissipate heat generated from the channel of the TFT to the outside, thereby improving driving failure due to internal heat generation during high temperature driving You can do it.

The heat dissipation layers 140 ′ and 140 ″ made of the conductive film may vary depending on the material of the conductive film, but may be formed to have a thickness of 500 Å to 1000 Å so as to transmit light.

When the display area AA of the TFT substrate 110 is described in detail with reference to FIGS. 5 and 6, a heat dissipation layer 140 and a buffer layer 111 are formed on a substrate 101 made of an insulating material such as transparent plastic. Is formed, and an active layer 114 is formed thereon.

In this case, as described above, the heat dissipation layer 140 may be formed of a conductive film having good heat conduction characteristics such as copper, aluminum, ITO, and the like, and may be formed to have a thickness of 500 Å to 1000 Å so as to transmit light.

The heat dissipation layer 140 may be formed on the substrate 101 of the GIP circuit portion CA and/or the display area AA.

The active layer 114 includes a channel and may be formed of hydrogenated amorphous silicon, polycrystalline silicon, or an oxide semiconductor.

In addition, a gate insulating film 115a made of a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ) is formed on the active layer 114, and a gate line (not shown) including a gate electrode 112 thereon. And a first sustain electrode 116 is formed.

An inter insulation layer 115b made of a silicon nitride film or a silicon oxide film is formed on the substrate 101 on which the gate line including the gate electrode 112 and the first storage electrode 116 are formed, A data line (not shown), a driving voltage line (not shown), source/drain electrodes 113a and 113b, and a second sustain electrode 117 are formed thereon.

At this time, the second storage electrode 117 overlaps a portion of the first storage electrode 116 under the interlayer insulating layer 115b to form a storage capacitor.

The source/drain electrodes 113a and 113b are electrically connected to the source/drain regions of the active layer 114 through a contact hole.

A protective film 115c made of a silicon nitride film or a silicon oxide film is formed on the substrate 101 on which the data line, the driving voltage line, the source/drain electrodes 113a and 113b, and the second sustain electrode 117 are formed.

A pixel electrode 118 is formed on the TFT substrate 110 configured as described above.

At this time, the pixel electrode 118, which is an anode, is electrically connected to the drain electrode 113b through a contact hole.

A partition 115d is formed on the substrate 101 on which the pixel electrode 118 is formed. At this time, the partition wall 115d surrounds the edge of the pixel electrode 118 like a bank to define an opening, and is made of an organic insulating material or an inorganic insulating material. The partition wall 115d may also be made of a photosensitive material containing a black pigment. In this case, the partition wall 115d serves as a light blocking member.

An organic compound layer 130 is formed on the substrate 101 on which the partition wall 115d is formed.

In this case, the organic compound layer 130 may have a multilayer structure including an auxiliary layer for improving luminous efficiency of the emission layer in addition to the emission layer emitting light. The auxiliary layers include an electron transport layer and a hole transport layer for balancing electrons and holes, and an electron injection layer and a hole injection layer for enhancing injection of electrons and holes.

A common electrode 128 as a cathode is formed on the organic compound layer 130.

In addition, pad electrodes for transmitting electric signals to the scan driver and the data driver are positioned in the pad area of the TFT substrate 110.

The encapsulation layer 120 is formed on the TFT and the organic light emitting diode 130 formed on the TFT substrate 110 to seal and protect the TFT and the organic light emitting diode 130 from the outside.

When this encapsulation layer 120 is described in detail, as an example, a first protective layer 123a, an organic layer 123b, and a secondary protective layer 123c are sequentially formed on the TFT substrate 110 on which the cathode 128 is formed. Is formed.

The primary passivation layer 123a is made of an inorganic insulating layer and thus has poor stack coverage due to a lower TFT step. However, since the organic layer 123b positioned thereon serves as a planarization layer, the secondary passivation layer 123c ) Is not affected by the step difference caused by the lower membrane. In addition, since the organic layer 123b made of a polymer is sufficiently thick, cracks caused by foreign substances may be compensated.

On the front surface of the TFT substrate 110 including the secondary protective layer 123c, a multi-layered protective film 125 is positioned opposite to each other for final sealing, and between the TFT substrate 110 and the protective film 125 A pressure-sensitive adhesive 124 that is transparent and has adhesive properties is interposed therebetween.

An integrated circuit chip (not shown) may be mounted in the pad area of the panel assembly 100 configured as described above in a chip on glass method.

Electronic elements (not shown) for processing driving signals are mounted on the flexible circuit board 106 in a chip on film method, and a connector (not shown) for transmitting an external signal to the flexible circuit board 106 (not shown) City) can be installed.

The flexible circuit board 106 is folded to the rear of the panel assembly 100 so that the flexible circuit board 106 faces the rear surface of the panel assembly 100. That is, in a state in which the encapsulation layer 120 is bonded to the TFT substrate 110 to form the panel assembly 100, the flexible circuit board 106 having a bending portion is attached to the rear surface of the organic light emitting display device through an adhesive layer (not shown). Will be attached.

As described above, in the flexible display device according to the first embodiment of the present invention, a conductive film such as copper, aluminum, or ITO having good heat conduction properties is provided on the substrate 101 of the GIP circuit unit CA and/or the display area AA. By forming the heat dissipation layers 140, 140 ′ and 140 ″ made of, the heat generated in the channel of the TFT is released to the outside, thereby improving driving failure due to internal heat generation during high temperature driving.

Hereinafter, a manufacturing process of the flexible display device according to the first exemplary embodiment constructed as described above will be described in detail with reference to the drawings.

7 is a flowchart sequentially showing a method of manufacturing a flexible display device according to the first embodiment of the present invention.

In addition, FIGS. 8A to 8E are perspective views sequentially illustrating a manufacturing process of the flexible display device according to the first embodiment of the present invention.

As shown in FIG. 8A, in order to manufacture the flexible display device according to the first embodiment of the present invention, first, an auxiliary substrate 150 is provided (S110).

Here, the auxiliary substrate 150 may serve to support the flexible substrate during a display panel process to be described later. In this case, the auxiliary substrate 150 may be a glass substrate or a metal substrate.

Thereafter, as shown in FIG. 8B, a sacrificial layer 155 is formed on the surface of the auxiliary substrate 150 (S120).

In this case, before forming the sacrificial layer 155 on the surface of the auxiliary substrate 150, a buffer layer made of a silicon nitride film may be formed. The buffer layer may serve to fix a flexible substrate to be formed on the auxiliary substrate 150 during a display panel process.

In this case, for example, the sacrificial layer 155 may be formed to a thickness of about 1 μm to 5 μm, preferably about 2 μm.

Next, as shown in FIG. 8C, a flexible substrate 101 is formed on the auxiliary substrate 150 on which the sacrificial layer 155 is formed (S130).

Here, as an example, the flexible substrate 101 may be formed by coating a polyimide resin on the sacrificial layer 155. However, the present invention is not limited thereto, and the flexible substrate 101 may be attached on the auxiliary substrate 150 on which the sacrificial layer 155 is formed.

Next, as shown in FIG. 8D, a predetermined heat dissipation layer 140 is formed on the flexible substrate 101 (S140).

The heat dissipation layer 140 may be formed of a conductive film having good heat conduction properties such as copper, aluminum, ITO, etc., and may be formed to have a thickness of 500 Å to 1000 Å so as to transmit light.

The heat dissipation layer 140 may be formed on the flexible substrate 101 of the GIP circuit part and/or the display area.

Thereafter, as shown in FIG. 8E, a predetermined process is performed on the flexible substrate 101 on which the heat dissipation layer 140 is formed to form the display panel 102 (S150).

Here, the display panel 102 may be any one of a liquid crystal display device, an organic light emitting display device, or an electrophoretic display device.

For example, when the display panel 102 is configured as an organic light emitting display device, a TFT substrate on which a plurality of TFTs are formed is manufactured by performing a predetermined TFT process on the flexible substrate 101. First, the heat dissipation layer 140 A buffer layer and an active layer may be formed on the formed flexible substrate 101.

A gate insulating film made of a silicon nitride film or a silicon oxide film or the like is formed on the flexible substrate 101 including the active layer, and a gate electrode, a gate line, and a sustain electrode may be formed thereon.

An interlayer insulating film made of a silicon nitride film or a silicon oxide film, etc. is formed on the flexible substrate 101 on which the gate electrode, the gate line, and the sustain electrode are formed, and a data line, a driving voltage line, and a source/drain electrode may be formed thereon. .

A protective film made of a silicon nitride film or a silicon oxide film may be formed on the flexible substrate 101 on which the data line, the driving voltage line, and the source/drain electrode are formed.

In addition, a pixel electrode may be formed on the passivation layer.

A partition wall may be formed on the flexible substrate 101 on which the pixel electrode is formed.

An organic compound layer may be formed on the flexible substrate 101 on which the barrier ribs are formed.

In this case, the organic compound layer may have a multilayer structure including an auxiliary layer for improving luminous efficiency of the emission layer in addition to the emission layer emitting light. The auxiliary layers include an electron transport layer and a hole transport layer for balancing electrons and holes, and an electron injection layer and a hole injection layer for enhancing injection of electrons and holes.

A common electrode as a cathode may be formed on the organic compound layer.

An encapsulation layer is formed on the entire surface of the TFT substrate on which the organic light-emitting diode is formed, and a polarizing plate for preventing reflection of light incident from the outside may be attached on the encapsulation layer.

Next, as shown in FIGS. 8F and 8G, the auxiliary substrate 150 is separated from the flexible substrate 101 on which the display panel 102 is formed by irradiating a laser.

As an example, the flexible substrate 101 on which the display panel 102 is formed is vertically inverted and loaded on the table 160 so that the auxiliary substrate 150 faces upward, and then the sacrificial layer 155 is irradiated with a laser from the top. Can be removed (S160). However, the present invention is not limited thereto, and the sacrificial layer 155 may be removed by irradiating a laser under the auxiliary substrate 150 on which the display panel 102 is formed.

In this case, when amorphous silicon is used as the sacrificial layer 155, hydrogen (H ₂ ) is generated inside the sacrificial layer 155 by the laser irradiation, so that the flexible substrate 101 and the auxiliary substrate 150 It is separated (S170).

9 is a cross-sectional view schematically illustrating a part of a display area in a flexible display device according to a second exemplary embodiment of the present invention, illustrating a flexible organic light emitting display device as an example.

In this case, FIG. 9 shows, for example, one subpixel including a TFT portion and a capacitor forming portion of an organic light emitting display device of a top emission type using a coplanar-structured TFT. However, the present invention is not limited to the structure and light emission method of the TFT.

In addition, the flexible display device according to the second embodiment of the present invention illustrated in FIG. 9 is a flexible display according to the first embodiment of the present invention described above, except that a heat radiation hole is formed in the flexible substrate instead of the heat radiation layer. It has substantially the same configuration as the device.

When the display area of the TFT substrate in which the heat dissipation hole is formed is described in detail with reference to FIG. 9, a buffer layer 211 is formed on a substrate 201 made of an insulating material such as transparent plastic, and an active layer 214 is formed thereon. Is formed.

At this time, the substrate 201 may be made of polyimide, and a heat dissipation hole (H) for dissipating heat generated from the channel to the outside is formed at a specific position of the polyimide substrate 201 under the channel. To do.

The polyimide substrate 201 may be formed to have a thickness of about 10 μm to 20 μm, and the heat dissipation hole H may have a size corresponding to or larger than that of the active layer 214 thereon. It is formed in the 201 and can expose the buffer layer 211 thereon.

The heat dissipation hole H may be formed in the substrate 201 of the GIP circuit part as well as the substrate 201 in the display area.

Further, the heat dissipation hole H may have a polygonal shape such as a circle, a triangle, or a rectangle, and one or more heat dissipation holes H may be formed corresponding to one active layer 214.

The active layer 214 includes a channel and may be formed of hydrogenated amorphous silicon, polycrystalline silicon, or an oxide semiconductor.

In addition, a gate insulating film 215a made of a silicon nitride film or a silicon oxide film is formed on the active layer 214, and a gate line (not shown) including a gate electrode 212 and a first storage electrode 216 are formed thereon. ) Is formed.

An interlayer insulating film 215b made of a silicon nitride film or a silicon oxide film is formed on the substrate 201 on which the gate line including the gate electrode 212 and the first sustain electrode 216 are formed, and a data line (not shown) is formed thereon. When), a driving voltage line (not shown), source/drain electrodes 213a and 213b, and a second sustain electrode 217 are formed.

In this case, the second storage electrode 217 overlaps a portion of the first storage electrode 216 under the interlayer insulating layer 215b to form a storage capacitor.

The source/drain electrodes 213a and 213b are electrically connected to the source/drain regions of the active layer 214 through a contact hole.

A protective film 215c made of a silicon nitride film or a silicon oxide film is formed on the substrate 201 on which the data line, the driving voltage line, the source/drain electrodes 213a and 213b, and the second sustain electrode 217 are formed.

A pixel electrode 218 is formed on the TFT substrate 210 constructed in this way.

At this time, the pixel electrode 218, which is an anode, is electrically connected to the drain electrode 213b through a contact hole.

A partition wall 215d is formed on the substrate 201 on which the pixel electrode 218 is formed. In this case, as described above, the partition wall 215d surrounds the edge of the pixel electrode 218 like a weir to define an opening, and is made of an organic insulating material or an inorganic insulating material. The partition wall 215d may also be made of a photosensitive material containing a black pigment. In this case, the partition wall 215d serves as a light blocking member.

An organic compound layer 230 is formed on the substrate 201 on which the partition wall 215d is formed.

In this case, the organic compound layer 230 may have a multi-layered structure including an auxiliary layer for improving luminous efficiency of the emission layer in addition to the emission layer emitting light. The auxiliary layers include an electron transport layer and a hole transport layer for balancing electrons and holes, and an electron injection layer and a hole injection layer for enhancing injection of electrons and holes.

A common electrode 228 as a cathode is formed on the organic compound layer 230.

10 is a flowchart sequentially illustrating a method of manufacturing a flexible display device according to a second exemplary embodiment of the present invention.

First, a predetermined auxiliary substrate is provided (S210).

The auxiliary substrate may serve to support the flexible substrate during a display panel process to be described later. In this case, the auxiliary substrate may be a glass substrate or a metal substrate.

Thereafter, a sacrificial layer is formed on the surface of the auxiliary substrate (S220).

In this case, before forming the sacrificial layer on the surface of the auxiliary substrate, a buffer layer made of a silicon nitride film may be formed. The buffer layer may serve to fix a flexible substrate to be formed on an auxiliary substrate during a display panel process.

In this case, for example, the sacrificial layer may be formed to a thickness of about 1 μm to 5 μm, preferably about 2 μm.

Next, a flexible substrate is formed on the auxiliary substrate on which the sacrificial layer is formed (S230).

Here, as an example, the flexible substrate may be formed by coating a polyimide resin on the sacrificial layer. However, the present invention is not limited thereto, and a flexible substrate may be attached on the auxiliary substrate on which the sacrificial layer is formed.

Next, a display panel is formed by performing a predetermined process on the flexible substrate (S240).

As described above, the display panel may be any one of a liquid crystal display device, an organic light emitting display device, or an electrophoretic display device.

Thereafter, the auxiliary substrate is separated from the flexible substrate on which the display panel is formed by irradiating the laser.

For example, after the flexible substrate on which the display panel is formed is vertically inverted and loaded on a table with the auxiliary substrate facing upward, the sacrificial layer may be removed by irradiating a laser thereon (S250). However, the present invention is not limited thereto, and the sacrificial layer may be removed by irradiating a laser under the auxiliary substrate on which the display panel is formed.

Next, a heat dissipation hole is formed in a specific position of the flexible substrate from which the auxiliary substrate is separated, that is, a region where the active layer is located (S270).

The heat dissipation hole may be formed in the flexible substrate with a size corresponding to or larger than that of the active layer thereon.

Such heat dissipation holes may be formed not only on the flexible substrate of the display area but also on the flexible substrate of the GIP circuit.

Although a number of matters are specifically described in the above description, this should be interpreted as an example of a preferred embodiment rather than limiting the scope of the invention. Therefore, the invention should not be determined by the described embodiments, but should be determined by the claims and equivalents to the claims.

101,201: substrate 111,211: buffer layer
114,214: active layer 140,140',140": heat dissipation layer
H: heat dissipation hole

Claims (17)

delete delete delete delete delete delete delete delete Forming a sacrificial layer made of amorphous silicon on the surface of the auxiliary substrate;
Forming a flexible substrate divided into a display area and a GIP circuit portion outside the auxiliary substrate on which the sacrificial layer is formed;
Forming a display panel on the flexible substrate;
Separating the auxiliary substrate from the flexible substrate by inverting the flexible substrate on which the display panel is formed so that the auxiliary substrate faces upward and removing the sacrificial layer from the top by laser irradiation; And
And forming a heat dissipation hole in the flexible substrate from which the auxiliary substrate is separated. delete delete The method of claim 9, wherein the heat dissipation hole is formed in the flexible substrate in a region where an active layer is located. 13. The method of claim 12, wherein the heat dissipation hole is formed in the flexible substrate with a size corresponding to or larger than that of the active layer thereon. 14. The method of claim 13, wherein the heat dissipation hole is formed not only on the flexible substrate of the display area but also on the flexible substrate of the GIP circuit. A flexible substrate divided into a display area and a GIP circuit part outside the display area;
A TFT formed on the flexible substrate and including an active layer; And
A flexible display device comprising: a heat dissipation hole formed in a flexible substrate in a region where the active layer is positioned to dissipate heat generated from a channel of the active layer to the outside. 16. The flexible display device of claim 15, wherein the heat dissipation hole is formed in the flexible substrate with a size corresponding to or larger than that of the active layer thereon. 16. The flexible display device of claim 15, wherein the heat dissipation hole is formed not only on the flexible substrate of the display area but also on the flexible substrate of the GIP circuit.

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