KR100592272B1 - Electroluminescent display device - Google Patents

Abstract

The present invention, a thin film transistor layer formed on one surface of the substrate; An insulating layer formed on one surface of the thin film transistor layer; And a pixel layer including a first electrode layer and a second electrode layer disposed on the insulating layer, and an electroluminescent part disposed therebetween, wherein the pixel layer includes: the insulating layer below the first electrode layer; A reflective layer is disposed on at least a portion of the region excluding the via hole of the layer, and an auxiliary conductive layer disposed below the reflective layer, wherein the auxiliary conductive layer extends to the via hole, wherein the first electrode layer and the auxiliary conductive layer are formed. And the layer is in direct contact with at least a portion of at least the adjacent portion of the via hole.

Description

Electroluminescence display device

1A is a schematic plan view of an organic electroluminescent display device according to the prior art,

FIG. 1B is an enlarged view of a portion “A” taken along line I-I of FIG. 1A, FIG.

2A is a schematic plan view of an organic electroluminescent display device according to an embodiment of the present invention;

FIG. 2B is a partially enlarged view of symbol “B” of FIG. 2A;

FIG. 2C is a partial cross sectional view taken along line II-II of FIG. 2B;

FIG. 2D is a partially enlarged view of symbol “C” of FIG. 2C;

3 is a schematic cross-sectional view of an organic electroluminescent display device according to another embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

110 substrate 120 buffer layer

130 ... semiconductor active layer 140 ... gate insulation layer

150 ... gate electrode 160 ... intermediate layer

170 Source / drain electrodes 180a, b ... protective layer

181a, b ... via hole 300 ... driven power supply line

310 driving line 400 second electrode layer

410 ... electrode power supply line 500 ... vertical drive circuit

600 ... horizontal drive circuit 800 ... sealed

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device, and more particularly, to a flat panel display device capable of increasing a screen aperture ratio and preventing luminance unevenness due to voltage drop in a display area.

In displaying an image, many kinds of display apparatuses are used. In recent years, various flat panel display apparatuses are used to replace conventional cathode ray tubes, that is, cathode ray tubes (CRTs). Such flat panel display apparatuses may be classified into an emissive type and a non-emissive type according to a light emitting form. Self-luminous display devices include flat CRTs, plasma display panel devices, vacuum fluorescent display devices, field emission display devices, and inorganic / organic electroluminescent display devices. a luminescent display device and the like, and a non-luminescent display device includes a liquid crystal display device. Among them, the organic electroluminescent device is a self-luminous device that does not need a separate light emitting device such as a backlight, and is a flat display device that has been in the spotlight in recent years for low power and high efficiency operation and blue light emission.

An organic electroluminescent display device utilizes a phenomenon in which electrons and holes injected through a cathode and an anode are recombined to form an exciton in an organic thin film, and light of a specific wavelength is generated by energy from the formed excitons. It is a self-luminous display device. The organic electroluminescent display device can be driven at low voltage, has a light weight, thinness, a wide viewing angle, and a fast response speed.

The organic electroluminescent portion of such an organic electroluminescent display element is composed of a first electrode as an anode formed on a substrate, an organic light emitting portion, and a second electrode as a cathode. The organic light emitting unit includes an organic light emitting layer (EML), in which holes and electrons recombine to form excitons and light is generated. In order to improve the light emission efficiency, holes and electrons should be more smoothly transported to the organic light emitting layer. For this purpose, an electron transport layer (ETL) may be disposed between the cathode and the organic light emitting layer, and a hole transport layer may be disposed between the anode and the organic light emitting layer. A hole transport layer (HTL) may be disposed, and a hole injection layer (HIL) may be disposed between the anode and the hole transport layer, and an electron injection layer (EIL, electron injction) between the cathode and the electron transport layer. layer) may be arranged.

On the other hand, organic electroluminescent display devices are classified into passive matrix (PM) type and passive matrix active matrix (AM) type according to the driving method. In the passive matrix type, the anode and the cathode are simply arranged in columns and rows, respectively, so that the cathode is supplied with a scanning signal from a row driving circuit. At this time, only one row of the plurality of rows is selected. In addition, a data signal is input to each pixel in the column driving circuit. On the other hand, the active matrix type is a thin film transistor (TFT) to control the input signal for each pixel is suitable for processing a large amount of signals are used as a display device for implementing a video.

FIG. 1A is a plan view of an active matrix type organic electroluminescent display device commonly used, and FIG. 1B is a partial cross-sectional view taken along the line I-I of FIG. 1A.

The illustrated active matrix organic electroluminescent display device has a predetermined display area 20 including an organic electroluminescent element on a transparent insulating substrate 11, and a sealing member (not shown), such as a metal cap, has a display area ( Sealed by seal 80 to seal 20). The display area 20 is composed of a plurality of pixels through an organic electroluminescent device including a thin film transistor, and a plurality of driving lines VDD and 31 are disposed in the display area 20. The driving power is connected to the terminal area 70 through the driving power wiring part 30 outside the display area 20 to supply driving power to the display area 20.

As shown in FIG. 1B, a thin film transistor layer 10a is formed on one surface of the substrate 11 to apply an electrical signal to the electroluminescent part constituting the display area 20, and includes an electroluminescent part thereon. The pixel layer 10c is formed, and the insulating layer 10b is interposed between the thin film transistor layer 10a and the pixel layer 10c.

Electrical communication between the thin film transistor layer 10a and the pixel layer 10c is performed in the via hole formed in the insulating layer 10b. FIG. 1C is an enlarged partial cross-sectional view of a portion denoted by reference numeral "A" in FIG. 1B. A first insulating layer 18a is formed on the drain electrode 17b, and a second insulating layer 18b is formed on the upper portion of the drain electrode 17b, and via holes 18'a and b are formed in each insulating layer.

In the case of the top emission type electroluminescent display device, a reflective layer 19b is formed under the first electrode layer 19a for supplying an electrical signal to the electroluminescent unit 19c constituting the display area 20 (see FIG. 1A). They are formed to extend to the via hole in the form of a double layer, thereby making electrical communication with the drain electrode 17b of the thin film transistor layer 10a.

In the case of a top emission type in which the first electrode layer 19a is used as the anode electrode layer, typically, the first electrode layer 19a mainly uses a transparent conductive oxide material such as ITO having a large work function, and Al is used as the reflective layer 19b. Alternatively, a reflective layer such as AlNd or the like is used. Between the first electrode layer made of ITO or the like and the metallic reflective layer made of a material such as AlNd, electrical conductivity is inhibited by the interfacial oxide layer therebetween, and the electrical conductivity is transmitted from the drain electrode 17b. Interfering with the signal being transmitted to the electroluminescent part disposed in the open area by the pixel defining layer 19d of the display area, the screen quality may be degraded, such as lowering or uneven brightness of the display area. .

In addition, in the case of the first electrode layer, in order to improve the color coordinates and resonance effects of light emitted from the organic electroluminescent part interposed between the first electrode layer and the second electrode layer, the first electrode layer formed of ITO or the like has a considerably small thickness. shall. In this case, when the first electrode layer is extended in the via hole for electrical communication between the pixel layer and the thin film transistor layer, partial step disconnection of the first electrode layer may not occur due to sufficient step coverage, thereby causing the first electrode layer. It may be accompanied by a problem of deterioration of the screen quality such as luminance deterioration and non-uniformity due to the reduction of the current delivered to the organic electroluminescent portion in close contact with the.

The present invention provides an electroluminescent display device and a method of manufacturing the same that can improve the screen quality through the enhancement of the brightness and color by facilitating electrical communication between the thin film transistor layer and the pixel layer.

In order to achieve the above object, according to one aspect of the invention,

A thin film transistor layer formed on one surface of the substrate;

An insulating layer formed on one surface of the thin film transistor layer; And

And a pixel layer including a first electrode layer and a second electrode layer disposed on the insulating layer, and an electroluminescent unit disposed therebetween.

The pixel layer includes:

A reflective layer disposed under the first electrode layer and disposed in at least a portion of a region excluding the via hole of the insulating layer;

An auxiliary conductive layer disposed below the reflective layer is further included,

The auxiliary conductive layer extends to the via hole, and the first electrode layer and the auxiliary conductive layer directly contact at least a portion of the via hole adjacent to each other.

According to another aspect of the invention, the auxiliary conductive layer is provided with an electroluminescent display device, characterized in that the metal layer.

According to another aspect of the invention, the metal layer, Mo, W, Ag, Au, Pd, Ni, Cu, Ta, TiN provides an electroluminescent display device characterized in that it comprises at least one material.

According to another aspect of the present invention, the metal layer is provided with an electroluminescent display device, characterized in that made of the same material as the source / drain electrode of the thin film transistor layer.

According to another aspect of the present invention, the first electrode layer extends to the via hole, and a direct contact portion of the first electrode layer and the auxiliary conductive layer includes the via hole portion. do.

According to another aspect of the present invention, the first electrode layer provides a electroluminescent display device, characterized in that the transparent conductive oxide layer.

According to another aspect of the invention, the first electrode layer is composed of ITO, the thickness provides a electroluminescent display device, characterized in that 10 ~ 300Å.

According to another aspect of the invention, the thickness of the auxiliary conductive layer is 300 kPa to 5000 kPa provides an electroluminescent display device.

According to another aspect of the present invention, a thin film transistor layer on one surface of a substrate; Insulating layer; And a pixel layer comprising a first electrode layer, a second electrode layer, and an electroluminescent part disposed therebetween, the method of manufacturing an electroluminescent display device comprising:

Forming a via hole in the insulating layer for electrical communication between the pixel layer and the thin film transistor layer;

Forming the auxiliary conductive layer formed on one surface of the insulating layer and extending to the via hole;

Forming a reflective layer on one surface of the auxiliary conductive layer, the reflective layer having an area smaller than that of the auxiliary conductive layer;

And forming a first electrode layer in at least a portion of the via hole adjacent to the auxiliary conductive layer to directly contact the auxiliary conductive layer.

According to yet another aspect of the present invention, there is provided a method of manufacturing an electroluminescent display device, wherein the first electrode layer extends to the via hole in the first electrode layer forming step.

According to another aspect of the present invention, in the auxiliary conductive layer forming step, a method of manufacturing an electroluminescent display device using the same material as the source / drain electrode of the thin film transistor layer as the auxiliary conductive layer forming material. To provide.

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

2A is a schematic plan view of an organic electroluminescent display device as an example of a flat panel display device according to an embodiment of the present invention.

As shown in FIG. 2A, a display area 200 in which a light emitting device such as an organic electroluminescent display device is disposed on one surface of the substrate 110 is applied along an outer side of the display area 200 to encapsulate the substrate 110 and an encapsulation material. A sealing part 800 for sealing a substrate (not shown) and a terminal area 700 in which various terminals are disposed are provided.

A driving power supply line 300 for supplying driving power to the display area 200 is disposed between the display area 200 and the sealing part 800. 2A is an example of the present invention, but the arrangement of the driving power supply line is not limited thereto, but the driving power supply line 300 may be improved by supplying uniform driving power throughout the display area. Is preferably formed to surround the display area.

The driving power supply line 300 is connected to the driving line 310, and the driving line 310 is disposed across the display area 200 and is disposed below the passivation layer 180 (see FIG. 2C). , See FIG. 2C).

In addition, the vertical / horizontal driving circuit units 500 and 600 are disposed outside the display area 200. The vertical driving circuit part 500 may be a scan driving circuit part for applying a scan signal to the display area 200, and the horizontal driving circuit part 600 may be a data driving circuit part for applying a data signal to the display area 200. In some cases, they may be disposed outside the sealing area in the form of an external IC or COG.

On the other hand, outside the display area 200, an electrode power supply line 410 for supplying electrode power to the display area 200 is disposed, which is formed on the display area 200, for example, a second surface formed Electrical communication is achieved through an electrode layer and via holes 430 such as an insulating layer formed therebetween.

The driving power supply line 300, the electrode power supply line 410, the horizontal / vertical driving circuit units 500, 600, and the like are connected to the terminals 320, 420, 520, and 620 for the respective components through wirings. Consists of, and makes electrical communication with the terminal portion 700 disposed outside the sealing area.

The organic electroluminescent device constituting the display area 200 will be described with reference to FIGS. 2B and 2C, but the encapsulation substrate, the sealing thin film layer, and the like are omitted for clarity. FIG. 2B schematically shows one pixel of the display area, indicated by reference B of FIG. 2A. 2B illustrates one pixel having a structure including two top gate type thin film transistors and one capacitor, which is only an example for describing the present invention and the present invention is not limited thereto.

The gate electrode 55 of the first thin film transistor TFT1 that determines whether to select the pixel extends from the scan line to which the scan signal is applied. When an electrical signal such as a scan signal is applied to the scan line, the data signal input through the data line is transferred from the source electrode 57a of the first thin film transistor TFT1 to the semiconductor active layer 53 of the first thin film transistor TFT1. ) Is transferred to the drain electrode 57b of the first thin film transistor TFT1.

The extension 57c of the first thin film transistor TFT1 drain electrode 57b is connected to the first electrode 58a of the capacitor, and the other end of the first thin film transistor TFT2 is a driving thin film transistor TFT2. The gate electrode 150 of FIG. 2C is formed, and the second electrode of the capacitor is electrically connected to the driving line 310 (see FIG. 2A).

2C is a partial cross-sectional view taken along the line II-II of FIG. 2B. In the case of the second thin film transistor TFT2, as shown in FIG. 2C, a thin film transistor layer, such as the second thin film transistor TFT2, is formed on one surface of the substrate 110. The semiconductor active layer 130 of the second thin film transistor TFT2 is formed on the buffer layer 120 formed on one surface of the substrate 110. The semiconductor active layer 130 may be composed of an amorphous silicon layer or may be composed of a polycrystalline silicon layer. Although not shown in detail in the drawing, the semiconductor active layer 130 includes a source and a drain region doped with N + or P + type dopants and a channel region. The thin film transistor including the semiconductor active layer 130 may be formed of an organic semiconductor. Various configurations are possible, such as can be made.

The gate electrode 150 of the second thin film transistor is disposed on the semiconductor active layer 130. The gate electrode 150 may be formed in consideration of adhesion to an adjacent layer, surface planarity and processability of the stacked layer, and the like. It is preferably formed of a material such as MoW, Al / Cu, but is not limited thereto.

A gate insulating layer 140 is disposed between the gate electrode 150 and the semiconductor active layer 130 to insulate them. An interlayer 160 as an insulating layer is formed on the gate electrode 150 and the gate insulating layer 140 as a single layer and / or a plurality of layers, and the source / drain of the second thin film transistor TFT2 is formed thereon. The electrodes 170a and b are formed, and the source / drain electrodes 170a and b may be formed of a metal such as MoW and the like, and may be formed later to achieve smoother ohmic contact with the semiconductor active layer 130. It may be heat treated.

On top of the source / drain electrodes 170a, b are passivation layers 180a, b as insulating layers, which may consist of passivation layers and / or planarization layers for protecting and / or planarizing the underlying layers. In the protective layers 180a and b according to an embodiment of the present invention, as shown in FIG. 2C, after forming the first protective layer 180a using an inorganic material such as SiNx, BCB (benzocyclobutene) is formed thereon. ) Or the second protective layer 180b formed of an organic material layer such as acrylic, but is not limited thereto, and may be formed in a single layer or may be formed in multiple layers.

A pixel layer including a first electrode layer 190, a second electrode layer 400, and an electroluminescence unit 192 disposed therebetween is formed on the thin film transistor layer, that is, on the passivation layers 180a and b. .

Once the protective layers 180a and b are formed, the via holes 181a and b are formed in the respective protective layers 180a and b. In some cases, the via holes are formed in the protective layer. May be formed collectively. The pixel layer is in electrical communication with the thin film transistor layer through the via holes 181a and b formed in the protective layers 180a and b as the insulating layer.

Thereafter, an area including the pixel opening 194 defined by the pixel defining layer 191 (see FIG. 2C) formed on the passivation layer 180b is later formed on the passivation layer 180a and b. The conductive layer 195 is formed. The auxiliary conductive layer 195 extends to the via hole 181b formed in the protective layer 180b. The auxiliary conductive layer 195 is in electrical communication with the source / drain electrodes 170a and b through the via hole 181b. .

After the auxiliary conductive layer 195 is formed, the pixel opening 194 is a region including the corresponding region, and a reflective layer 193 is formed on one surface of the auxiliary conductive layer 195, and the first electrode layer 190 is formed thereon. Is formed. The reflective layer 193 formed on one surface of the auxiliary conductive layer 195 is a conductive reflective layer such as Al, AlNd, Cr, Ti, or the like.

FIG. 2D is an enlarged partial cross-sectional view of symbol “C” of FIG. 2C. As shown in FIG. 2D, the auxiliary conductive layer 195 extending to the via hole 181b directly contacts the first electrode layer 190 at at least a portion of the adjacent portion of the via hole 181b. The first electrode layer 190 preferably has a structure covering the reflective layer 193. Therefore, it is preferable that the first electrode layer 190 covers the reflective layer 193 so that the first electrode layer 190 and the auxiliary conductive layer 195 surround the reflective layer 193.

Meanwhile, the auxiliary conductive layer 195 directly contacting the first electrode layer 190 may be formed of various conductive materials. For example, the auxiliary conductive layer 195 may be formed of a metal layer. The metal layer may be composed of a metal layer including one or more of materials such as Mo, W, Ag, Au, Pd, Ni, Cu, Ta, TiN, MoW, and the like.

Since the auxiliary conductive layer 195 extends to the via hole 181b and is in electrical communication with the source / drain electrodes 170a and b, when the auxiliary conductive layer 195 is formed of a metal layer, the auxiliary conductive layer 195 In order to solve a problem such as an increase in contact resistance occurring between dissimilar metals at the contact surface between the source and the drain electrodes 170a and b, the auxiliary conductive layer 195 is the same as the source / drain electrodes 170a and b. It is preferably formed of a material.

On the other hand, as shown in FIG. 3, the first electrode layer 190 covering the reflective layer 193 extends to the via hole 181b so as to secure excellent conductivity by increasing the contact area with the auxiliary conductive layer 195. It is desirable to form a direct contact area between the first electrode layer 190 and the auxiliary conductive layer 195. In addition, the first electrode layer 190 may be formed of a transparent conductive oxide layer, for example, a transparent conductive oxide such as ITO. When the first electrode layer 190 is formed of ITO, the first electrode layer 190 may be formed through the pixel opening 194. It is preferable that the thickness of the first electrode layer 190 is 10 kPa to 300 kPa to obtain an appropriate color coordinate and improved resonance effect of the emitted light and to perform an appropriate function as the first electrode layer.

In addition, the auxiliary conductive layer 195 should have an appropriate thickness in order to prevent a disconnection that may occur when the auxiliary conductive layer 195 extends to the via hole 181b and to prevent a decrease in yield due to excessive increase in process time. However, it is preferable that it is 300 kV to 5000 kV.

On the other hand, after the first electrode layer 190 is formed, the pixel defining layer 191 is formed on the passivation layer 180b to the region except the pixel opening 194. An organic electroluminescence unit 192 including an emission layer may be disposed on one surface of the first electrode layer 190 through the pixel opening 194, and the second electrode layer 400 may be formed on the entire surface thereof.

The organic electroluminescent unit 192 may be formed of a low molecular or polymer organic film. When the low molecular organic film is used, a hole injection layer (HIL), a hole transport layer (HTL), and an organic light emitting layer (EML) An emission layer, an electron transport layer (ETL), and an electron injection layer (EIL) may be formed by stacking a single or a complex structure, and the usable organic material may be copper phthalocyanine (CuPc: copper). phthalocyanine), N, N-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl-benzidine: NPB A variety of materials can be applied, including tris-8-hydroxyquinoline aluminum (Alq3). These low molecular weight organic films are formed by the vacuum deposition method.

In the case of the polymer organic film, the structure may include a hole transporting layer (HTL) and an organic light emitting layer (EML). In this case, PEDOT is used as the hole transporting layer, and polyvinylvinylene (PPV) and polyflu as the light emitting layer. Polymeric organic materials such as orene (Polyfluorene) are used, and various configurations are possible, such as being formed by screen printing or inkjet printing.

The second electrode layer 400 as a cathode is deposited on the top of one surface of the organic light emitting unit 192, and the second electrode layer 400 is not limited to this type of front deposition, and depending on the type, Al / Ca, It may be formed of a material such as ITO, Mg-Ag, or the like, may be formed of a plurality of layers instead of a single layer, and may be further provided with an alkali or alkaline earth metal fluoride layer such as LiF. Can be.

The above embodiments are examples for describing the present invention, but the present invention is not limited thereto. That is, although the above embodiments have been described with respect to the organic electroluminescent display device, various modifications can be considered within the scope including the configuration of the present invention, such that the present invention can be sufficiently applied to the inorganic electroluminescent display device within the scope of the present invention.

The present invention as described above has the following effects.

First, by not extending the reflective layer to the via hole, the auxiliary conductive layer extending to the via hole while preventing luminance decrease due to a decrease in the current supplied to the electroluminescent part due to the contact resistance generated between the reflective layer and the first electrode layer. By transmitting an electrical signal to the first electrode layer by solving the problem of pixel defects caused by disconnection of the first electrode layer, it is possible to improve the overall screen quality of the electroluminescent display device.

Second, according to the present invention, the electrical communication between the thin film transistor layer and the pixel layer is made through the auxiliary conductive layer, thereby increasing the degree of freedom in controlling the thickness of the first electrode layer, thereby improving the screen quality due to the improvement of color coordinates and the resonance effect.

Third, the present invention can reduce the contact resistance that may occur during electrical communication between the pixel layer and the source / drain electrodes by forming the auxiliary conductive layer, preferably a metal layer of the same material as the source / drain electrodes.

Fourth, the present invention takes the structure surrounding the reflective layer and / or extends the first electrode layer to the via hole, thereby increasing the direct contact area between the auxiliary conductive layer and the first electrode layer, thereby facilitating the electrical signal from the thin film transistor layer. The brightness may be improved by transferring the light to the electroluminescent unit.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (11)

A thin film transistor layer formed on one surface of the substrate; An insulating layer formed on one surface of the thin film transistor layer; And And a pixel layer including a first electrode layer and a second electrode layer disposed on the insulating layer, and an electroluminescent unit disposed therebetween. The pixel layer includes: A reflective layer disposed under the first electrode layer and disposed in at least a portion of a region excluding the via hole of the insulating layer; An auxiliary conductive layer disposed below the reflective layer is further included, The auxiliary conductive layer extends to the via hole, wherein the first electrode layer and the auxiliary conductive layer are in direct contact with at least a portion of the via hole adjacent to at least a portion thereof. The method of claim 1, The auxiliary conductive layer is an electroluminescent display device, characterized in that the metal layer. The method of claim 2, The metal layer is an electroluminescent display device comprising at least one of Mo, W, Ag, Au, Pd, Ni, Cu, Ta, TiN. The method of claim 2, And the metal layer is made of the same material as the source / drain electrodes of the thin film transistor layer. The method of claim 1, The first electrode layer extends to the via hole, and the direct contact portion of the first electrode layer and the auxiliary conductive layer includes the via hole portion. The method of claim 1, The first electrode layer is a transparent conductive oxide layer, characterized in that the electroluminescent display device. The method of claim 1, And the first electrode layer is made of ITO and has a thickness of 10 kPa to 300 kPa. The method of claim 1, And the thickness of the auxiliary conductive layer is 300 kPa to 5000 kPa. A thin film transistor layer on one surface of the substrate; Insulating layer; And a pixel layer comprising a first electrode layer, a second electrode layer, and an electroluminescent part disposed therebetween, the method of manufacturing an electroluminescent display device comprising: Forming a via hole in the insulating layer for electrical communication between the pixel layer and the thin film transistor layer; Forming the auxiliary conductive layer formed on one surface of the insulating layer and extending to the via hole; Forming a reflective layer on one surface of the auxiliary conductive layer, the reflective layer having an area smaller than that of the auxiliary conductive layer; And forming a first electrode layer in direct contact with the auxiliary conductive layer in at least a portion of the via hole adjacent portion. The method of claim 9, And forming the first electrode layer up to the via hole in the first electrode layer forming step. The method of claim 9, And forming the auxiliary conductive layer using the same material as the source / drain electrode of the thin film transistor layer as the auxiliary conductive layer forming material.

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