Organic light-emitting display apparatus

An organic light-emitting display apparatus may include a substrate; a thin-film transistor (TFT) disposed on the substrate, and having an active layer, a gate electrode, a source electrode and a drain electrode; a signal line formed on the same layer as the source electrode and the drain electrode; a first insulating layer covers the signal line, the source electrode, and the drain electrode; a pixel electrode formed on the first insulating layer, and electrically connected to the TFT; a pixel-defining layer formed on the first insulating layer, includes an opening exposing the pixel electrode; an intermediate layer formed on the pixel electrode, and includes a light-emitting layer; and an opposite electrode formed on the intermediate layer. The intermediate layer is formed on the pixel-defining layer so as to overlap with the signal line.

CLAIM OF PRIORITY

This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on the 13thof Jun. 2011 and there duly assigned Serial No. 10-2011-0057006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to one or more embodiment of an organic light-emitting display apparatus.

2. Description of the Related Art

In general, a flat display device is largely classified into a light-emitting type and a light-receiving type. Light-emitting type display devices include flat cathode ray tubes, plasma display panels, electroluminescent display devices, light-emitting diode display devices, or the like. Light-receiving type display devices include liquid crystal displays (LCDS) or the like. Among these display devices, electroluminescent display devices have advantages such as wide viewing angles, excellent contrast, and rapid response speeds, thus drawing attention to the electroluminescent display device as a next-generation display apparatus. Electroluminescent display devices may be an organic electroluminescent device or an inorganic electroluminescent device (e.g., organic light emitting display devices) according to the material forming a light-emitting layer.

The organic electroluminescent device is a self-emission display which performs electrical excitation of an organic fluorescent compound and emits light. The organic electroluminescent device allows driving at a low voltage, facilitates preparation of a thin film, and provides wide viewing angles and rapid response speeds, thereby drawing attention as a next-generation display apparatus which may solve problems with an LCD.

The organic electroluminescent device includes a light-emitting layer, which is formed of an organic material, between an anode electrode and a cathode electrode. In the organic electroluminescent device, as a positive electrode voltage and a negative electrode voltage are respectively applied to the anode electrode and the cathode electrode, a hole injected from the anode electrode moves to the light-emitting layer via a hole transport layer (HTL) and an electron moves from the cathode electrode to the light-emitting layer via a electron transport layer (ETL). Thus, an electron and a hole recombine at the light-emitting layer to thus generate an exciton.

When the excitons are changed from an excitation state to a ground state, fluorescent molecules of the light-emitting layer emit light, thus forming an image. A full-color organic electroluminescent device is formed to include a pixel which displays three colors including red, green and blue, thereby implementing full colors.

In such an organic electroluminescent device, a pixel-defining layer is formed on both edges of the anode electrode. Then, a predetermined opening is formed in the pixel-defining layer, and a light-emitting layer and a cathode electrode are sequentially formed on a surface of the anode electrode which is exposed by the opening.

SUMMARY OF THE INVENTION

One or more aspects of the present invention provide an organic light-emitting display apparatus in which a parasitic capacitance at a wiring is reduced.

According to an aspect of the present invention, there is provided an organic light-emitting display apparatus which may include a substrate; a thin-film transistor (TFT) which is disposed on the substrate and includes an active layer and a gate electrode which are insulated from each other, and a source electrode and a drain electrode which are electrically connected to each other; a signal line formed on the same layer as the source electrode and the drain electrode; a first insulating layer which covers the signal line, the source electrode, and the drain electrode; a pixel electrode which is formed on the first insulating layer and is electrically connected to the TFT; a pixel-defining layer which is formed on the first insulating layer and includes an opening exposing the pixel electrode; an intermediate layer which is formed on the pixel electrode and includes a light-emitting layer; and an opposite electrode which is formed on the intermediate layer. The intermediate layer may be formed on the pixel-defining layer so as to overlap with the signal line.

The first insulating layer, the pixel-defining layer, and the intermediate layer may be disposed between the signal line and the opposite electrode.

The intermediate layer may be formed on the pixel electrode, may extend over a side of the pixel electrode so as to correspond to the signal line, and may be formed on the pixel-defining layer.

A second insulating layer may be formed between the gate electrode and the source and drain electrodes, and the signal line, the source electrode and the drain electrode may be formed on the second insulating layer.

The neighboring intermediate layers may overlap with each other and may be disposed on the pixel-defining layer which corresponds to the signal line.

The intermediate layer may include a first common layer, the light-emitting layer, and a second common layer which are sequentially stacked, the first common layer and the second common layer may be commonly formed on the pixel-defining layer and the pixel electrode, and the light-emitting layer may be formed on the pixel electrode so as to extend to the pixel-defining layer which corresponds to the signal line.

The first common layer may include a hole injection layer (HIL) and a hole transport layer (HTL) which are sequentially stacked.

The second common layer may include an electron transport layer (ETL) and an electron injection layer (EIL) which are sequentially stacked.

According to another aspect of the present invention, there is provided an organic light-emitting display apparatus which may include a substrate; a thin-film transistor (TFT) which is disposed on the substrate and includes an active layer and a gate electrode which are insulated from each other, and a source electrode and a drain electrode which are electrically connected to each other; a signal line formed on the same layer as the source electrode and the drain electrode; a pixel electrode which is formed on the same layer as the gate electrode and is electrically connected to the TFT; a pixel-defining layer which covers the signal line, the source electrode and the drain electrode, and which includes an opening exposing the pixel electrode; an intermediate layer which is formed on the pixel electrode and includes a light-emitting layer; and an opposite electrode which is formed on the intermediate layer. The intermediate layer may be formed on the pixel-defining layer so as to overlap with the signal line.

The pixel-defining layer and the intermediate layer may be disposed between the signal line and the opposite electrode.

The intermediate layer may be formed on the pixel electrode, may extend from a side of the pixel electrode so as to correspond to the signal line, and may be formed on the pixel-defining layer.

The first insulating layer may be formed between the active layer and the gate electrode, the pixel electrode may be formed on the first insulating layer, and a second insulating layer may be formed between the gate electrode and the source and drain electrodes, and the signal line, the source electrode and the drain electrode may be formed on the second insulating layer.

The neighboring intermediate layers may overlap with each other and may be disposed on the pixel-defining layer which corresponds to the signal line.

The intermediate layer may include a first common layer, the light-emitting layer, and a second common layer which are sequentially stacked, the first common layer and the second common layer may be commonly formed on the pixel-defining layer and the pixel electrode, and the light-emitting layer may be formed on the pixel electrode so as to extend to the pixel-defining layer which corresponds to the signal line.

The first common layer may include a hole injection layer (HIL) and a hole transport layer (HTL) which are sequentially stacked.

The second common layer may include an electron injection layer (EIL) and an electron transport layer (ETL) which are sequentially stacked.

DETAILED DESCRIPTION OF THE INVENTION

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

FIG. 1is a schematic cross-sectional view of an organic light-emitting display apparatus according to an embodiment of the present invention.

Referring toFIG. 1, the organic light-emitting display apparatus according to an embodiment of the present invention may include a substrate10, a thin-film transistor (TFT), a pixel electrode61, an intermediate layer62, an opposite electrode63, and a signal line60. The TFT may include an active layer52, a gate electrode54, a source electrode56, and a drain electrode57.

Specifically, the substrate10may be formed of transparent glass having silicon dioxide (SiO2) as a main component. However, the substrate10is not limited thereto, and it may also be formed of transparent plastic. The transparent plastic for forming the substrate10may be one selected from the group of insulating organic materials consisting of polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelene naphthalate (PEN), polyethyelene terephthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propionate (CAP).

A buffer layer11may be formed on the substrate10. The buffer layer11may provide a flat surface on the substrate10and prevents penetration of moisture and foreign substances into the substrate10.

The active layer52may be formed on the buffer layer11. The active layer52may be formed of an inorganic semiconductor or an organic semiconductor. The active layer52includes source and drain areas52band52c, respectively. The source and drain areas52band52c, respectively, are doped with an n-type or p-type impurity. The active layer52also may include a channel area52afor connecting the source and drain areas52band52c, respectively.

The organic semiconductor forming the active layer52may include a polymer organic material such as a polythiophene and a derivative thereof, a poly(p-phenylene vinylene) (PPV) and a derivative thereof, a poly(para-phenylene) (PPP) and a derivative thereof, a polythiophene vinylene and a derivative thereof, and a polythiophene-heterocyclic aromatic copolymer and a derivative thereof. The organic semiconductor may include a low-molecular weight organic material such as oligoacene of a pentacene, a tetracene, and a naphthalene and a derivative thereof, oligothiophene of alpha-5-thiophene and alpha-6-thiophene and a derivative thereof, phthalocyanine including or not including a metal and a derivative thereof, pyromellitic dianhydride and a derivative thereof, pyromellitic diimide and a derivative thereof, perylenetetracarboxylic dianhydride and a derivate thereof, and perylenetetracarboxylic diimide and a derivative thereof.

The active layer52is covered by a gate insulating layer13. The gate electrode54may be formed on the gate insulating layer13. The gate electrode54may be formed so as to cover an area corresponding to the channel area52aof the active layer52. The gate electrode54may be formed of a metal or a metal alloy such as gold (Au), silver (Ag), copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), aluminum (Al), an aluminum-neodymium (Al:Nd) alloy, or a molybdenum tungsten (Mo:W) alloy. However, the gate electrode54is not limited thereto, and may include various conductive materials. The gate electrode54may be connected to a gate line (not illustrated) which transmits ON and OFF signals to the TFT. The active layer52and the gate electrode54may be insulated from each other by the gate insulating layer13.

A second insulating layer14is formed to cover the gate electrode54. The source electrode56and the drain electrode57may be formed on the second insulating layer14. The source electrode56and the drain electrode57may be connected to the source area52band the drain area52c, respectively, of the active layer52through a contact hole formed in the gate insulating layer13and the second insulating layer14.

The source electrode56and the drain electrode57may be formed of Au, Ag, Pd, Pt, Ni, rhodium (Rh), ruthenium (Ru), iridium (Ir), or osmium (Os). Besides these materials, the source electrode56and the drain electrode57may also be formed of two or more metal alloys using Al, molybdenum (Mo), an Al:Nd alloy, or a MoW alloy. However, the source electrode56and the drain electrode57are not limited thereto, and may be formed of other materials.

The signal line60may be formed on the second insulating layer14on which the source electrode56and the drain electrode57are formed. The signal line60is connected to the TFT and may transmit a signal from outside. The signal line60may be formed of the same material as the source electrode56and the drain electrode57. Thus, the signal line60, the source electrode56and the drain electrode57may be formed simultaneously by using one patterning process.

A first insulating layer15may be formed so as to cover the signal line60, the source electrode56and the drain electrode57. The first insulating layer15may be formed of inorganic materials such as silicon dioxide (SiO2), silicon nitride (SiNx), and the like, or organic materials such as acryl, polyimide, Benzocyclobutene (BCB), and the like.

The pixel electrode61may be formed on the first insulating layer15. The pixel electrode61may be connected to the drain electrode57through a via-hole. The pixel electrode61may be formed of a transmission electrode or a reflective electrode.

When the pixel electrode61is a transmission electrode, the pixel electrode61includes indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium oxide (In2O3). When the pixel electrode61is a reflective electrode, the pixel electrode61is formed by forming a reflective layer using at least one material consisting of Ag, magnesium (Mg), Al, Pt, Pd, Au, Ni, neodymium (Nd), Ir, chrome (Cr), and a combination thereof, and then forming a layer on the reflective layer using ITO, IZO, ZnO, or In2O3.

In the current embodiment, the drain electrode57is connected to the pixel electrode61. However, the present invention is not limited thereto, and the source electrode56may be connected to the pixel electrode61.

A pixel-defining layer70may be formed on the first insulating layer15. The pixel-defining layer70contains various insulating materials and includes an opening exposing a predetermined area of the pixel electrode61. The intermediate layer62may be formed on the exposed pixel electrode61. The opposite electrode63may be formed on the intermediate layer62. The intermediate layer62may also be formed on an area70aof the pixel-defining layer70which corresponds to the signal line60, as well as on the pixel electrode61, as described below.

The intermediate layer62includes a light-emitting layer (not illustrated). The light-emitting layer may emit light when a voltage is applied to the pixel electrode61and the opposite electrode63.

When the light-emitting layer of the intermediate layer62is formed of a low-molecular weight organic material, a hole transport layer (HTL) and a hole injection layer (HIL) are disposed between the light-emitting layer and the pixel electrode61, and an electron transport layer (ETL) and an electron injection layer (EIL) are disposed between the light-emitting layer and the opposite electrode63. Besides these layers, other layers may be disposed as necessary. Various organic materials that may be used include copper phthalocyanine (CuPc), N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), tris-8-hydroxyquinoline aluminum (Alq3), and the like.

When the light-emitting layer of the intermediate layer62is formed of a polymer organic material, the HTL may be included between the light-emitting layer and the pixel electrode61. The HTL may be formed of poly-(2,4)-ethylene-dihydroxy thiophene (PEDOT) or polyaniline (PANI). Organic materials that may be used include polymer organic materials such as PolyPhenylene Vinylene (PPV), Polyfluorene, and the like.

The opposite electrode63is formed to cover all pixels. The opposite electrode63may be a transmission electrode or a reflective electrode.

When the opposite electrode63is a transmission electrode, the opposite electrode63is formed by stacking a layer which is formed of lithium (Li), calcium (Ca), lithium-fluoride-calcium (LiF/Ca), lithium-fluoride-aluminum (LiF/Al), Al, Ag, Mg or a combination thereof and a transmissive conductive layer which is formed of ITO, IZO, ZnO, or In2O3. When the opposite electrode63is a reflective electrode, the opposite electrode63includes Li, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg, or a combination thereof.

In the current embodiment, the pixel electrode61and the opposite electrode63are assumed to be an anode electrode and a cathode electrode, respectively. However, the present invention is not limited thereto, and the polarity of the pixel electrode61and the polarity of the opposite electrode63may be the opposite thereto. Furthermore, materials forming the pixel electrode61and the opposite electrode63are illustrative examples of the invention. Thus, other materials may be used to form the pixel electrode61and the opposite electrode63.

A sealing member (not illustrated) may be disposed on the opposite electrode63. The sealing member (not illustrated) is formed to protect the intermediate layer62and other layers from external moisture or oxygen. The sealing member (not illustrated) is formed of a transparent material. The sealing member (not illustrated) may also be formed in a multi-layer structure in which glass, plastic, or organic and inorganic materials overlap.

The opposite electrode63, which is a common electrode, is formed on an entire surface of the substrate10. The signal line60is disposed below the opposite electrode63. Therefore, a parasitic capacitance is generated between the opposite electrode63and the signal line60. The parasitic capacitance may deteriorate the performance of the organic light-emitting display apparatus, for example, a signal delay.

According to an embodiment of the present invention, the intermediate layer62is formed to extend on the pixel-defining layer70on an area corresponding to the signal line60, thus decreasing the parasitic capacitance generated between the opposite electrode63and the signal line60. That is, the intermediate layer62is formed on the pixel electrode61and extends from a side of the pixel electrode61to the pixel-defining layer70so as to overlap with the signal line60. Referring toFIG. 1, the intermediate layer62may also be formed on the area70aof the pixel-defining layer70which corresponds to the signal line60. Accordingly, the first insulating layer15, the pixel-defining layer70, and the intermediate layer62are interposed between the signal line60and the opposite electrode63. Besides, a parasitic capacitance at the first insulating layer15, a parasitic capacitance at the pixel-defining layer70, and a parasitic capacitance at the intermediate layer62are connected in series. Accordingly, the entire parasitic capacitance between the signal line60and the opposite electrode63may be reduced, thus minimizing deterioration of characteristics of the TFT.

FIG. 2is a schematic cross-sectional view of an organic light-emitting display apparatus according to another embodiment of the present invention.

Referring toFIG. 2, the organic light-emitting display apparatus according to another embodiment of the present invention may include a substrate10, a TFT, pixel electrodes61aand61b, intermediate layers62aand62b, an opposite electrode63, and a signal line60. The TFT may include an active layer52, a gate electrode54, a source electrode56, and a drain electrode57.

The organic light-emitting display apparatus illustrated inFIG. 2differs from the organic light-emitting display apparatus ofFIG. 1in terms of disposition of the intermediate layers62aand62b. Referring toFIG. 2, the neighboring intermediate layers62aand62bmay overlap with each other and may be disposed on an area70aof a pixel-defining layer70which corresponds to the signal line60. The intermediate layer62ais disposed on the pixel electrode61a, and the intermediate layer62bis disposed on the pixel electrode61bwhich is disposed to the left of the pixel electrode61a. The intermediate layers62aand62bare disposed on the pixel electrodes61aand61b, respectively, and extend over a side of the pixel electrodes61aand61b, respectively, on the area70aof the pixel-defining layer70. Thus, on the area70aof the pixel-defining layer70, the intermediate layer62amay be disposed below the intermediate layer62b. In the organic light-emitting display apparatus illustrated inFIG. 2, a first insulating layer15, the pixel-defining layer70, the intermediate layer62a, and the intermediate layer62bare sequentially interposed between the signal line60and the opposite electrode63, thus minimizing an overall parasitic capacitance.

FIG. 3is a schematic cross-sectional view of an organic light-emitting display apparatus according to another embodiment of the present invention.

Referring toFIG. 3, the organic light-emitting display apparatus according to another embodiment of the present invention may include a substrate10, a TFT, pixel electrodes61aand61b, intermediate layers62aand62b, an opposite electrode63, and a signal line60a. The TFT may include an active layer52, a gate electrode54, a source electrode56, and a drain electrode57.

The organic light-emitting display apparatus illustrated inFIG. 3differs from the organic light-emitting display apparatus ofFIG. 1in terms of the structure and disposition of the intermediate layers62aand62b. Referring toFIG. 3, the intermediate layer62amay include a first common layer621, a light-emitting layer622a, and a second common layer623. The intermediate layer62bmay include the first common layer621, a light-emitting layer622b, and the second common layer623. Like the opposite electrode63, the first common layer621and the second common layer623are commonly formed on an entirety of the pixel defining layer70and an entirety of the pixel electrodes61aand61bover an entire surface of the substrate10. However, the light-emitting layers622aand622bmay be formed on the pixel layers61aand61b, respectively, between the first common layer621and the second common layer623. The first common layer may be formed of a HTL and a HIL. The second common layer623may be formed of an ETL and an EIL.

The light-emitting layers622aand622bmay be formed so as to extend to an area70aof the pixel-defining layer70which corresponds to the signal line60a. That is, the light-emitting layer622a, which is formed on the pixel electrode61a, may extend over a side of the pixel electrodes61aon the area70aof the pixel-defining layer70which corresponds to the signal line60a. Thus, a first insulating layer15, the pixel-defining layer70, the first common layer612, the light-emitting layer622a, and the second common layer623are interposed between the signal line60aand the opposite electrode63, thus minimizing an overall parasitic capacitance between the signal line60aand the opposite electrode63.

FIG. 4is a schematic cross-sectional view of an organic light-emitting display apparatus according to another embodiment of the present invention.

Referring toFIG. 4, the organic light-emitting display apparatus according to another embodiment of the present invention may include a substrate110, a TFT, a pixel electrode114, an intermediate layer118, an opposite electrode119, and a signal line160. The TFT may include an active layer212, first and second gate electrodes214and215, respectively, a source electrode216b, and a drain electrode216a.

A buffer layer111may be formed so as to provide a flat surface on the substrate101and prevent penetration of moisture and foreign substances into the substrate110.

The active layer212of the TFT may be formed on the buffer layer111. The active layer212may be formed of a semiconductor which includes amorphous silicon or crystalline silicon. The active layer212may include source and drain areas121band121a, respectively, which are doped with an ion impurity, and a channel area121c.

On the active layer212, the first gate electrode214and the second gate electrode215, which include a transparent conductive material, may be sequentially formed at a location which corresponds to the channel area121cof the active layer212, with a first insulating layer113interposed therebetween.

The source and drain electrodes216band216a, respectively, connected to the source and drain areas121band121a, respectively, of the active layer212, are formed on the first and second gate electrodes214and215, respectively, with a second insulating layer115interposed therebetween. A pixel-defining layer117may be formed on the second insulating layer115so as to cover the source and drain electrodes216band216a, respectively.

A first pixel electrode114, which is formed of the same material as the first gate electrode214, and a second pixel electrode116, which is formed of the same material as the second gate electrode215and which is located on edges of the first pixel electrode114, are sequentially formed on the substrate110, the buffer layer111and the first insulating layer113.

The current embodiment illustrates a structure in which the second pixel electrode116is located on edges of the first pixel electrode114. However, the present invention is not limited thereto, and may also include a structure in which the second pixel electrode116is not on the first pixel electrode114.

An opposite electrode119may be included at a location which faces the first pixel electrode114. The intermediate layer118, which includes a light-emitting layer (not illustrated), may be formed between the first pixel electrode114and the opposite electrode119.

A light-emitting layer of the intermediate layer118may be formed of a polymer organic material or a low-molecular weight organic material. When the light-emitting layer of the intermediate layer118is formed of a low-molecular weight organic material, a hole transport layer (HTL) and a hole injection layer (HIL) are disposed between the light-emitting layer and the pixel electrode114, and an electron transport layer (ETL) and an electron injection layer (EIL) are disposed between the light-emitting layer and the opposite electrode119. Besides these layers, other layers may be stacked as desired. Various organic materials, such as copper phthalocyanine (CuPc), N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), and tris-8-hydroxyquinoline aluminum(Alq3), may be used.

When the light-emitting layer of the intermediate layer118is formed of a polymer organic material, the HTL as well as the light-emitting layer may be included. The HTL may be formed by using PEDOT or PANI. Organic materials that may be used include polymer organic materials, such as PPV, Polyfluorene, and the like.

The opposite electrode119may be deposited on the intermediate layer118as a common electrode. In the case of the organic light-emitting display apparatus according to the current embodiment, the first and second pixel electrodes114and116, respectively, may be used as anode electrodes, and the opposite electrode119may be used as a cathode electrode, or vice versa.

The opposite electrode119may be formed as a reflective electrode which includes a reflective material. The opposite electrode119may include at least one material from the group consisting of Ag, Mg, Li, Ca, LiF/Ca, and LiF/Al.

When the opposite electrode119is included as a reflective electrode, light emitted from the intermediate layer118is reflected by the opposite electrode119, penetrates the first pixel electrode114which is formed of a transparent conductive material, and is emitted toward the substrate110.

A sealing member (not illustrated) may be disposed on the opposite electrode119. The sealing member (not illustrated) is formed to protect the intermediate layer118and other layers from external moisture or oxygen. The sealing member (not illustrated) is formed of a transparent material. The sealing member (not illustrated) may also be formed in a multi-layer structure in which glass, plastic, or organic and inorganic materials overlap.

In the current embodiment, the intermediate layer118is formed so as to extend to the pixel-defining layer117, thus minimizing a parasitic capacitance generated between the opposite electrode119and the signal line160. That is, the intermediate layer118may be formed on the pixel electrode114and may extend from a side of the pixel electrode114to the pixel-defining layer117so as to overlap with the signal line160. Referring toFIG. 4, the intermediate layer118may also be formed on an area117aon the pixel-defining layer117which corresponds to the signal line160. Accordingly, the pixel-defining layer117and the intermediate layer118are interposed between the signal line160and the opposite electrode119, and a parasitic capacitance at the pixel-defining layer117and a parasitic capacitance at the intermediate layer118are connected in series with each other, thereby minimizing an entire parasitic capacitance between the signal line160and the opposite electrode119. Therefore, deterioration of characteristics of the TFT may be minimized.

FIG. 5is a schematic cross-sectional view of an organic light-emitting display apparatus according to another embodiment of the present invention.

Referring toFIG. 5, the organic light-emitting display apparatus may include a substrate110, a TFT, pixel electrodes114aand114b, intermediate layers118aand118b, an opposite electrode119, and a signal line160. The TFT may include an active layer212, gate electrodes214and215, a source electrode216b, and a drain electrode216a.

The organic light-emitting display apparatus illustrated inFIG. 5differs from the organic light-emitting display apparatus ofFIG. 4in terms of disposition of the intermediate layers118aand118b. Referring toFIG. 5, the neighboring intermediate layers118aand118bmay overlap with each other at an area117aof a pixel-defining layer117which corresponds to the signal line160. The intermediate layer118ais disposed on the pixel electrode114a, and the intermediate layer118bis disposed on the pixel electrode114bwhich is disposed to the left of the pixel electrode114a. The intermediate layers118aand118bare disposed on the pixel electrodes114aand114b, respectively, and extend over a side of the pixel electrodes114aand114b, respectively, at the area117aof the pixel-defining layer70. Thus, at the area117aof the pixel-defining layer117, the intermediate layer118amay be disposed below the intermediate layer118b. In the organic light-emitting display apparatus illustrated inFIG. 5, the pixel-defining layer117, the intermediate layer118aand the intermediate layer118bare sequentially interposed between the signal line160and the opposite electrode119, thus decreasing an entire parasitic capacitance.

FIG. 6is a schematic cross-sectional view of an organic light-emitting display apparatus according to another embodiment of the present invention.

Referring toFIG. 6, the organic light-emitting display apparatus according to the present embodiment of the present invention may include a substrate110, a TFT, pixel electrodes114aand114b, intermediate layers118aand118b, an opposite electrode119, and a signal line160. The TFT may include an active layer212, gate electrodes214and215, a source electrode216b, and a drain electrode216a.

The organic light-emitting display apparatus illustrated inFIG. 6differs from the organic light-emitting display apparatus ofFIG. 4in terms of structure and disposition of the intermediate layers118aand118b. Referring toFIG. 6, the intermediate layer118aincludes a first common layer1181, a light-emitting layer1182a, and a second common layer1183. The intermediate layer118bmay include the first common layer1181, a light-emitting layer1182b, and the second common layer1183. Like the opposite electrode119, the first common layer1181and the second common layer1183are commonly formed on an entirety of the pixel-defining layer117and an entirety of the pixel electrodes114aand114bover an entire surface of the substrate110. However, the light-emitting layers1182aand1182bare formed on the pixel electrodes114aand114b, respectively, between the first common layer1181and the second common layer1183.

The first common layer1181may be formed of a HTL and a HIL. The second common layer1183may be formed of an ETL and an EIL.

The light-emitting layers1182aand1182bmay be formed to extend on an area117aof the pixel-defining layer117which corresponds to the signal line160. That is, the light-emitting layer1182a, which is formed on the pixel electrode114a, may extend over a side of the pixel electrode114aand may be formed on the area117aof the pixel-defining layer117which corresponds to the signal line160. Thus, the pixel-defining layer117, the first common layer1181, the light-emitting layer1182a, and the second common layer1183are interposed between the signal line160and the opposite electrode119, thus minimizing an overall parasitic capacitance between the signal line160and the opposite electrode119.

According to embodiments of the present invention, a parasitic capacitance of an organic light-emitting display apparatus may be reduced.