KR20170133732A - Flexible Substrate And Array Substrate Including The Same - Google Patents

Abstract

The present invention relates to a flexible substrate and an array substrate including the same. According to the present invention, a flexible display apparatus including the array substrate can be provided by providing the array substrate including the flexible substrate. Also, damages of the flexible substrate or a pad electrode when reworking a module can be prevented by providing the flexible substrate having a protrusion at an edge thereof and the array substrate including the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible substrate and an array substrate including the flexible substrate.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a flexible substrate and an array substrate including the same, and more particularly, to a flexible substrate capable of module rework without damage and an array substrate including the flexible substrate.

An organic light emitting diode display device, which is one of a flat panel display (FPD), has high luminance and low operating voltage characteristics. In addition, since it is a self-luminous type that emits light by itself, it has a large contrast ratio, can realize an ultra-thin display, can realize a moving image with a response time of several microseconds (μs), has no viewing angle limit, And it is driven with a low voltage of 5 to 15 V direct current, so that it is easy to manufacture and design a driving circuit.

In addition, the fabrication process of the organic light emitting diode display device is very simple because it is a deposition process and an encapsulation process.

Organic light emitting diode display devices having such characteristics are classified into a passive matrix type and an active matrix type.

For example, in the active matrix method, a thin film transistor (TFT), which is a switching element for turning on / off a pixel region, is located for each pixel region, and a driving thin film transistor is connected to a switching TFT, And an organic light emitting diode (OLED).

 At this time, the first electrode connected to the driving thin film transistor is turned on / off in the pixel region unit, and the second electrode facing the first electrode serves as a common electrode, Thereby forming the organic light emitting diode.

In the active matrix system having such a constitutional characteristic, the voltage applied to the pixel region is charged in the storage capacitor StgC, and power is applied until the next frame signal is applied, Continue to run for one screen without. Accordingly, since the same luminance is exhibited even when a low current is applied, an active matrix type organic light emitting diode (OLED) display device is mainly used since it has advantages of low power consumption, high definition, and large size.

On the other hand, in order to maximize the flexibility of the organic light emitting diode display device, a plastic substrate having a thickness of about 10 μm to 200 μm has been used as a base. When an organic light emitting diode display device is manufactured using such a plastic substrate having high flexibility, there arises a problem that it is difficult to maintain a flat state on a stage and to use between unit process lines due to the flexible nature of the plastic substrate. Therefore, after bonding a plastic substrate to a separate carrier substrate, components such as driving TFTs are formed on a plastic substrate, and the carrier substrate is removed to complete an organic light emitting diode display device having excellent flexibility.

 1A to 1D are schematic cross-sectional views illustrating a process of manufacturing an organic light emitting diode display device using a conventional flexible substrate and a module rework process.

First of all, as shown in FIG. 1A, a hydrogenated (hydrogenated) carrier substrate 5 having a characteristic that hydrogen gas is generated by laser beam irradiation on a carrier substrate 5 made of a glass material capable of laser beam transmission, Amorphous silicon (a-Si: H) is deposited to form the laser ablation layer 7.

Next, as shown in Fig. 1B, the plastic substrate 11 is formed by coating liquid plastic on the ablation layer 7 and continuously performing heat treatment.

Next, as shown in FIG. 1C, a plurality of gates and data lines (not shown) and switching and driving thin film transistors (not shown) are formed on the plastic substrate 11, An organic light emitting diode E including a first electrode 47 connected to a drain electrode (not shown) of the transistor DTr, an organic light emitting layer 55, and a second electrode 58 is formed. Then, a protective sheet 80 is attached to protect the organic light emitting diode E.

Next, a driving integrated circuit (IC) 83 is connected to a gate and a data pad portion provided with a gate and a data pad electrode (not shown) in a non-display area NA outside the display area AA, A flexible printed circuit board (FPCB) 82 is mounted.

The plurality of ICs of the driving circuit unit are typically electrically connected to the gate and data pad portions of the display panel by a TCP (Tape Carrier Package) mounting method or a COG (chip on glass) mounting method. A module rework process is performed when a defect occurs due to an integrated circuit failure, a TCP defect, or a bonding defect after the FPCB (flexible printed circuit board) 82 provided with the driving IC 83 is mounted The integrated circuit mounted thereon is separated and a new integrated circuit is attached or the integrated circuit after the defect correction is mounted again.

That is, as shown in FIG. 1D, when a module rework process is performed, damage to the substrate, the metal wiring, or the device occurs. Particularly, in the case of a flexible display using a plastic substrate, damage to the flexible substrate due to a module rework process largely occurs.

The present invention attempts to solve the problem of damage to a pad electrode or a flexible substrate by a module rework process.

In order to achieve the above-described object, the present invention provides a flexible substrate including a base having a first thickness and a projection positioned on the base at a first edge.

In addition, the second to fourth edges may be flexible substrates having the first thickness.

The protrusions may be flexible substrates having a plurality of protrusions spaced apart from each other.

The flexible substrate may be a flexible substrate having a thickness of 8 mu m to 10 mu m at the base and a thickness of 16 mu m to 20 mu at the first edge.

Each of the base and the protrusions may be formed of a material selected from the group consisting of polyethylene terephthalate, polyester, PC, PI, PEN, polyetheretherketone (PEEK), polyarylate (PAR) a flexible substrate made of any one of polycylicolefin, polynorbornene, polyethersulphone (PES), and cycloolefin polymer (COP).

According to another aspect of the present invention, there is provided a liquid crystal display device comprising: a flexible substrate; a gate wiring and a data line crossing each other on the flexible substrate and the flexible substrate; One pad electrode and a thin film transistor located in the pixel and connected to the gate line and the data line, and a pixel electrode connected to the thin film transistor.

The array substrate may further include a second pad electrode connected to the other end of the gate line and the data line and positioned on the protrusion.

The present invention can provide a flexible display device including the array substrate including the flexible substrate.

In addition, the present invention provides a flexible substrate having protrusions at the edges and an array substrate including the flexible substrate, thereby preventing damages to the flexible substrate or the pad electrode during module rework.

1A to 1D are schematic cross-sectional views illustrating a process of manufacturing an organic light emitting diode display device using a conventional flexible substrate and a module rework process.
2 is a circuit diagram for one subpixel of the organic light emitting diode display device
3A to 3K are schematic cross-sectional views illustrating a manufacturing process and a module rework process of an organic light emitting diode display device according to an embodiment of the present invention.
4A to 4E are schematic views showing a manufacturing process of a flexible substrate of the present invention.
5A to 5F are schematic views showing a manufacturing process of a flexible substrate of the present invention.
6A to 6G are schematic cross-sectional views of a flexible substrate according to an embodiment of the present invention.
FIGS. 7 and 8 are photographs showing the occurrence of damages caused by a module rework process as a comparative example.

Hereinafter, preferred embodiments of a flexible substrate and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

2 is a circuit diagram for one subpixel P of the organic light emitting diode display device.

As shown, each subpixel P of the organic light emitting diode display device includes a switching thin film transistor STr, a driving thin film transistor DTr, a storage capacitor StgC, and an organic light emitting diode E .

A data line DL is defined by defining a subpixel P in a second direction that intersects the first direction and a gate line GL is formed in a first direction. And a power supply line PL for applying a power supply voltage is formed.

 In addition, a switching thin film transistor STr is formed at a portion where the data line DL and the gate line GL cross each other, and the sub pixel P is electrically connected to the switching thin film transistor STr A driving thin film transistor DTr is formed.

At this time, the driving thin film transistor DTr is electrically connected to the organic light emitting diode E. That is, the drain electrode of the driving thin film transistor DTr is connected to the organic light emitting diode E, and the source electrode of the driving thin film transistor DTr is connected to the power supply line PL. At this time, the power supply line PL transfers a power supply voltage to the organic light emitting diode E. A storage capacitor StgC is formed between the gate electrode and the source electrode of the driving thin film transistor DTr.

Therefore, when a signal is applied through the gate line GL, the switching thin film transistor STr is turned on and the signal of the data line DL is transmitted to the gate electrode of the driving thin film transistor DTr, The light is emitted from the organic light emitting diode E because the thin film transistor DTr is turned on. At this time, when the driving thin film transistor DTr is turned on, the level of a current flowing from the power supply line PL to the organic light emitting diode E is determined, the storage capacitor StgC can maintain a constant gate voltage of the driving thin film transistor DTr when the switching thin film transistor STr is turned off, The level of the current flowing through the organic light emitting diode E can be kept constant until the next frame even if the switching thin film transistor STr is turned off.

Hereinafter, a flexible substrate according to an embodiment of the present invention and a manufacturing method thereof will be described

FIGS. 3A to 3K are schematic cross-sectional views illustrating a fabrication process and a module rework process of an organic light emitting diode to which a flexible substrate according to an embodiment of the present invention is applied.

 A region where the driving thin film transistor is formed in each pixel region P in the display region is defined as a driving region DA, and a region where the switching thin film transistor is formed is defined as a switching region (not shown).

First, as shown in Figs. 3A and 3B, flexible substrates 110 and 111 having protrusions 111 at their edges are formed on a carrier substrate 105 made of glass. For example, a display area NA, a non-display area NA, and a pixel area P are defined in the base 110 and a protrusion 111 is formed at the edge of the non-display area NA of the base 110 do. That is, the protrusion 111 is formed in a region to which the FPCB is to be attached.

In the present invention, the base 110 and the protrusions 111 may be made of polyethylene terephthalate (PET), polyester, PC (Polycarbonate), PI (polyimide), PEN (polyethylene naphthalate) , PAR (polyarylate), PCO (polycyclic olefin), polynorbornene, PES (polyethersulphone), and COP (cycloolefin polymer).

Figs. 4 and 5 are schematic cross-sectional views showing a manufacturing process of the flexible substrate of the present invention.

Hereinafter, the process of forming the flexible substrates 110 and 111 having the protruding portions 111 will be described in detail as a polyimide (hereinafter referred to as PI) as an example.

The processes for forming the flexible substrates 110 and 111 having the protrusions 111 are a one step process and a two step process.

4A to 4E are views showing a process of forming the flexible substrates 110 and 111 having the projections 111 in a single step process.

4A to 4C, PI is coated on the entire surface of the carrier substrate 105 to form a base 110. PI is formed on the edge except for the finishing coating area where the nozzle is positioned at the edge of the base 110, Lt; / RTI > Next, the base 110 and the protrusions 111 are formed by performing the heat treatment.

Thereafter, array elements (not shown) such as TFTs are formed and the carrier substrate 105 is separated, as shown in Figs. 4D and 4E, Thereby completing the array substrate. The carrier substrate 105 and the flexible substrates 110 and 111 can be separated from each other by, for example, laser beam (LB) irradiation.

FIGS. 5A to 5F are views showing a process of forming the flexible substrates 110 and 111 having the projections 111 in a two step process.

As shown in FIGS. 5A and 5B, PI is coated on the entire surface of the carrier substrate 105, and then a flat base 110 is formed by heat treatment.

Next, as shown in FIGS. 5C and 5D, the protrusions 111 are formed on the base 110 by applying the PI corresponding to the edges except the non-coated region and heat-treating them.

5D and FIG. 5F, the carrier substrate 105 is separated to separate the flexible substrate (not shown) having the protrusion 111 at the edge of the base 110 110, < RTI ID = 0.0 > 111). ≪ / RTI > The carrier substrate 105 and the flexible substrates 110 and 111 can be separated from each other by, for example, laser beam (LB) irradiation.

The thickness of the base 110 of the flexible substrate may be 8 um to 10 um and the thickness of the edges of the flexible substrates 110 and 111 having the protrusion 111 may be 16 um to 20 um.

By forming the protruding portion 111 at the edge as described above, the peel strength is increased at the edge of the flexible substrate, so that the gate pad electrode 181 and the data pad Thereby preventing the electrodes (not shown) and the flexible substrates 110 and 111 from being damaged.

Although it is not shown in the drawing, it is also possible to use an inorganic material such as silicon oxide (SiO 2) to facilitate separation of the base 110 and the carrier substrate 105 before forming the plastic layer on the carrier substrate 105 SiO 2) or silicon nitride (SiN x) is deposited on the entire surface of the carrier substrate 105 to form a bonding relaxed layer (not shown).

Next, as shown in Fig. 3C, a gate wiring (not shown) and a data wiring 130 which cross the interlayer insulating film 123 and define the pixel region P are formed on the flexible substrates 110 and 111, (Not shown) spaced apart from the gate wiring (not shown) or the data wiring 130. The gate wiring (not shown) and the data wiring 130 are connected to one ends of the gate wiring A pad electrode 181 and a data pad electrode (not shown) are formed on the protrusion 111.

A switching thin film transistor (not shown) connected to the gate wiring (not shown) and the data wiring 130 is connected to the switching region in each pixel region P surrounded by the gate wiring (not shown) and the data wiring 130 And a driving thin film transistor DTr connected to the switching thin film transistor (not shown) and the power source wiring (not shown) is formed in the driving region DA.

More specifically, a semiconductor layer 113 is formed on the base 110. For example, amorphous silicon is deposited to form an amorphous silicon layer (not shown), and the amorphous silicon layer is crystallized into a polysilicon layer (not shown) by irradiation with a laser beam or heat treatment. Thereafter, a mask process is performed to pattern the polysilicon layer (not shown) to form a semiconductor layer 113 in a pure polysilicon state.

Next, silicon oxide (SiO 2) is deposited on the semiconductor layer 113 of pure polysilicon to form a gate insulating layer 116. A first metal layer (not shown) is deposited on the gate insulating layer 116 by depositing a metal material such as aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, And a mask process is performed to form a gate electrode 120 corresponding to a central portion of the semiconductor layer 113.

At this time, a gate wiring (not shown) connected to a gate electrode (not shown) formed in a switching region (not shown) of the gate electrode 120 and extending in one direction and a gate electrode (181).

Next, the gate electrode 120 is doped with impurities at both ends of the semiconductor layer 113 by doping an impurity, that is, a trivalent element or a pentavalent element, using a blocking mask. Therefore, the semiconductor layer 113 includes the first region 113a of the polysilicon and the second region 113b which is located on both sides of the first region 113a and doped with the impurity.

Next, a semiconductor layer contact hole 125 exposing the second region 113b is formed on a substrate 110 having a semiconductor layer 113 divided into first and second regions 113a and 113b. For example, an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiO2) is deposited on the entire surface of the flexible substrate 110 or 111 on which the semiconductor layer 113 is formed to form an interlayer insulating film 123 on the entire surface The semiconductor layer contact hole 125 exposing the second region 113b may be formed by simultaneously or collectively patterning the interlayer insulating layer 123 and the lower gate insulating layer 116 by performing a mask process.

Thereafter, a metal material such as aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, chromium (Cr), and molybdenum (Mo) is deposited on the interlayer insulating layer 123, And the source and drain electrodes 133 and 136 are formed in contact with the second region 113b through the semiconductor layer contact hole 125 by patterning.

A data line 130 connected to a source electrode (not shown) formed in the switching region (not shown) on the interlayer insulating layer 123 and intersecting the gate line (not shown) to define a pixel region P (Not shown) spaced apart from the data line 130 and arranged side by side. Also, a data pad electrode (not shown) is formed which is connected to the end of the data line 130 and is located in the non-display area NA.

At this time, the semiconductor layer 113, the gate insulating layer 116, the gate electrode 120, the interlayer insulating layer 123, and the source and drain electrodes 133 and 136 are connected to the driving thin film transistor DTr And a switching thin film transistor (not shown) having substantially the same structure as the driving thin film transistor DTr is formed in the switching region (not shown).

Next, as shown in FIG. 3D, an inorganic insulating material such as silicon oxide (SiO2) or silicon nitride (SiNx) is deposited on the source and drain electrodes 133 and 136, or an organic insulating material such as photo- a passivation layer 140 is formed by applying a photo acryl or benzocyclobutene (BCB) and patterning to form a drain contact hole 143 for exposing the drain electrode 136 of the driving thin film transistor DTr do.

Next, as shown in FIG. 3E, indium-tin-oxide (ITO) or indium-zinc-oxide (IZO), which is a transparent conductive material having a relatively high work function value, is deposited and patterned on the passivation layer 140, A first electrode 147 is formed which contacts the drain electrode 136 of the driving thin film transistor DTr through a drain contact hole 143. The first electrode 147 may serve as an anode of the organic light emitting diode.

On the other hand, the first electrode 147 may have a double layer structure of a metal layer having a reflection characteristic and a transparent conductive material layer. For example, the metal layer may be made of any one of aluminum (Al), aluminum alloy (AlNd), and silver (Ag).

Next, as shown in FIG. 3F, a bank 150 is formed on the first electrode 147. For example, the bank 150 is formed by coating an organic insulating material such as photo acryl or benzocyclobutene (BCB) and patterning it. The bank 150 may overlap each edge of the first electrode 147 with the edge of each pixel region P

Next, as shown in FIG. 3G, an organic light emitting layer 155 is formed on the first electrode 147. Although the organic light emitting layer 155 has a single layer structure in the drawing, a hole injection layer, a hole transporting layer, an emitting material layer (light emitting material layer) ), An electron transporting layer (an electron transporting layer), and an electron injection layer (a multilayer structure).

Next, as shown in FIG. 3H, a second electrode 158 is formed on the organic light emitting layer 155. For example, a metal material having a relatively low work function value such as aluminum (Al), aluminum alloy (AlNd), silver (Ag), magnesium (Mg), gold (Au), aluminum- The second electrode 158 may be formed on the entire surface of the display area AA by depositing any one of the silver (Ag) -galline (MgAg). The second electrode 158 may serve as a cathode.

At this time, the first electrode 147, the organic light emitting layer 155, and the second electrode 158, which are sequentially stacked in each pixel region P, form an organic light emitting diode E.

Next, as shown in FIG. 3I, a protective film 170 is formed on the organic light emitting diode (E).

Next, as shown in FIG. 3J, the gate electrode 181 of the non-display area NA outside the display area AA exposed to the outside of the protective film 170 in a state where the protective film 170 is attached, A flexible printed circuit board (FPCB) 182 provided with a driving IC 183 is attached to a gate and a data pad portion provided with a data pad electrode (not shown). At this time, although not shown, a drive circuit board (not shown) is attached to the end of the FPCB 182.

For example, when a defect occurs in the FPCB 182, a module rework process is performed to separate the FPCB 182 from the flexible substrate as shown in FIG. 3K.

In the present invention, a protrusion 111 is formed in a portion where a flexible printed circuit board (FPCB) 182 provided with a driving IC 183 is to be mounted so that the driving IC 183 is provided when the module re- The damage to the gate pad electrode 181 or the data pad electrode (not shown) or the flexible substrate 110 or 111 is minimized or prevented even if the flexible printed circuit board (FPCB) 182 is removed. That is, damage to the gate pad electrode 181 or the data pad electrode (not shown) or the flexible substrate 110 or 111 by the module rework process can be minimized or prevented.

Although the organic light emitting diode display device is shown as an example in the embodiment of the present invention, it can be extended to all display devices, for example, a liquid crystal display device or an electrophoretic display device in which a flexible substrate is used.

6A to 6G show various forms of the flexible substrates 110 and 111 having the projections 111 at the edges as an embodiment of the present invention.

6A to 6E show a case where the protrusion 111 is formed in the shape of a bar on the edge, and FIGS. 6F and 6G show a case where the plurality of protrusions 111 are formed in a shape in which the protrusions 111 are spaced apart from each other .

As shown in FIG. 6A, in the flexible substrate including the base 110 in which the first to fourth edges are defined, the protrusion 111 is formed only on the first edge.

Thus, the flexible substrate has a first thickness at the central portion and second to fourth edges, and a second thickness at the first edge that is greater than the first thickness.

Referring to FIG. 6B, in the flexible substrate including the base 110 in which the first to fourth edges are defined, the protrusions 111 are formed at the first and third edges opposite to each other.

Thus, the flexible substrate has a first thickness at the center and at the second and fourth edges, and a second thickness at the first and third edges that is greater than the first thickness.

Referring to FIG. 6C, in the flexible substrate including the base 110 in which the first to fourth edges are defined, the protrusion 111 is formed at two adjacent edges, that is, the first and fourth edges.

Thus, the flexible substrate has a first thickness at the center and at the second and third edges and a second thickness at the first and fourth edges that is greater than the first thickness.

6D, in the flexible substrate including the base 110 in which the first to fourth edges are defined, the protrusion 111 is formed at the adjacent three edges, i.e., the first, second, and fourth edges.

Thus, the flexible substrate has a first thickness at the central portion and the third edge, and a second thickness at the first, second and fourth edges greater than the first thickness.

Referring to FIG. 6E, protrusions 111 are formed on all four edges of base 1110. Thus, the flexible substrate has a first thickness at the center and a second thickness at four edges that is greater than the first thickness.

Meanwhile, as shown in FIGS. 6F and 6G, a plurality of protrusions 111 may be formed on the edge of the base 110 so as to be spaced apart from each other. Since the gate pad electrode (or the data pad electrode) formed at the edge of the base 110, that is, the non-display area of the flexible substrate, are spaced apart from each other, the protrusion 111 is formed only in a portion where a plurality of gate pad electrodes are formed .

In such a case, the flexible substrate has a concave-convex cross section at the edge.

7 and 8 show, as a comparative example, a photograph showing whether a damage has occurred to the gate pad electrode 181 or the data pad electrode (not shown) or the flexible substrate 110 or 111 by the module rework process to be.

As shown in Fig. 7, when a flexible substrate having a single thickness is used, the metal wiring of the lower end portion may be torn off. Therefore, when a module for a module rework process is separated, a module rework process is performed by damaging the gate pad electrode 181 or the data pad electrode (not shown) or the flexible substrate (not shown) It can not proceed smoothly.

8, when the flexible substrates 110 and 111 including the protruding portion 111 and having a larger edge than the center are used, the FPCB (FPCB) provided with the driving IC 183, the module rework process can be smoothly performed because the gate pad electrode 181 or the data pad electrode (not shown) or the flexible substrate 110 or 111 is not damaged even if the flexible printed circuit board 182 is removed. And can save cost and time.

Further, in the present invention, since the projection 111 is formed at the edge of the non-display area NA, the optical characteristics of the display area AA are maintained.

105: carrier substrate 110: base
113: semiconductor layer 113a: first region
113b: second region 116: gate insulating film
120: gate electrode 123: interlayer insulating film
125: semiconductor layer contact hole 133: source electrode
136: drain electrode 140: protective layer
143: drain contact hole 147: first electrode
155: organic light emitting layer 158: second electrode
170: protective film 111:
181: gate pad electrode P: pixel region
182: FPCB 183: IC
AA: display area NA: non-display area
ALA: Array Element and Organic Light Emitting Diode
DTr: driving thin film transistor E: organic light emitting diode

Claims (7)

A base having a first thickness;
And a protrusion located on the base at a first edge.
The method according to claim 1,
And the second to fourth edges have the first thickness.
The method according to claim 1,
And a plurality of the protrusions are arranged apart from each other.
The method according to claim 1,
Wherein the flexible substrate has a thickness of 8 um to 10 um at the base and a thickness of 16 um to 20 um at the first edge.
The method according to claim 1,
Each of the base and the protrusions may be formed of a material selected from the group consisting of PET (polyethylene terephthalate), polyester, PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate), PEEK (polyether ether ketone) ), A polynorbornene, a polyethersulphone (PES), and a cycloolefin polymer (COP).
A flexible board according to any one of claims 1 to 5;
A gate wiring and a data wiring crossing each other on the flexible substrate to define a pixel;
A first pad electrode connected to one end of the gate line and the data line and positioned on the protrusion;
A thin film transistor located in the pixel and connected to the gate wiring and the data wiring;
And a pixel electrode connected to the thin film transistor.
The method according to claim 6,
And a second pad electrode connected to the other end of the gate line and the data line and positioned on the protrusion.

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