Organic Light-Emitting Diode Display Device

Abstract

To provide an organic light emitting diode display device.SOLUTION: An organic light emitting diode display device comprises: a substrate; a first voltage line and a second voltage line on the substrate; a first scan line and a second scan line which are sequentially provided in plan view on the substrate; a data line which crosses the first scan line and the second scan line; a first thin film transistor which is connected to the second scan line and the data line and in a periphery of the second scan line; a second thin film transistor which is connected to the first thin film transistor; an OLED which is connected to the first voltage line and the second thin film transistor; a third thin film transistor which is connected to the second thin film transistor, the OLED and the second scan line and in the periphery of the second scan line; a fourth thin film transistor which is connected to the second thin film transistor and the third thin film transistor and in a periphery of the first scan line; and a storage capacitor element which is connected to the second thin film transistor and on an opposite side of the first scan line with respect to the second scan line.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an organic light-emitting display device. [Background technology]

[0002] An organic light-emitting display device comprises two electrodes and an organic light-emitting layer located between them. Electrons injected from one electrode and holes injected from the other electrode combine in the organic light-emitting layer to form excitons, which then emit light by releasing energy.

[0003] Such an organic light emitting display device includes a plurality of pixels each including an organic light emitting diode (OLED) as a self-emitting element, and each pixel includes a plurality of thin film transistors and a capacitor for driving the OLED. The plurality of thin film transistors basically includes a switching thin film transistor and a driving thin film transistor.

[0004] For fast switching, the switching thin film transistor forms a thin gate insulating film between the gate electrode and the semiconductor layer. Since the gate insulating film of the driving thin film transistor, which is formed in the same layer as the switching thin film transistor, is also thin, the driving range of the gate voltage applied to the gate electrode of the driving thin film transistor is narrowed. Therefore, it is difficult to control the magnitude of the gate voltage (Vgs) of the driving thin film transistor to achieve a wide range of gray levels. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been devised to solve the above-mentioned problems of the background art, and relates to an organic light emitting display device capable of expressing a wide range of gray scales by widening the driving range of a driving thin film transistor. [Means for solving the problem]

[0006] An organic light emitting display device according to an embodiment of the present invention includes a substrate, scan lines formed on the substrate for transmitting scan signals, data lines and drive voltage lines crossing the scan lines for transmitting data signals and drive voltages, respectively, switching thin film transistors connected to the scan lines and the data lines, a driving thin film transistor connected to a switching drain electrode of the switching thin film transistor, and an organic light emitting diode connected to a driving drain electrode of the driving thin film transistor, wherein a driving semiconductor layer of the driving thin film transistor may be curved.

[0007] The semiconductor device may further include a first gate insulating layer covering the driving semiconductor layer, and a storage capacitor formed on the first gate insulating layer and overlapping the driving semiconductor layer.

[0008] The storage capacitor may include a first storage storage plate formed on the first gate insulating layer and overlapping the driving semiconductor layer, a second gate insulating layer covering the first storage storage plate, and a second storage storage plate formed on the second gate insulating layer and overlapping the first storage storage plate.

[0009] The driving semiconductor layer may include a plurality of bent portions.

[0010] The driving semiconductor layer may include a plurality of first extension portions extending in a first direction and a plurality of second extension portions extending in a second direction different from the first direction, and the bent portion may connect the first extension portions and the second extension portions.

[0011] The display device may further include a compensation thin film transistor that compensates for a threshold voltage of the driving thin film transistor and is connected to the driving thin film transistor.

[0012] The organic light emitting diode may further include an emission control thin film transistor that is turned on in response to an emission control signal transmitted through an emission control line to transmit a driving voltage from the driving thin film transistor to the organic light emitting diode, and the emission control thin film transistor may be located between a driving drain electrode of the driving thin film transistor and the organic light emitting diode.

[0013] The compensation source electrode of the compensation thin film transistor and the emission control source electrode of the emission control thin film transistor may be connected through a transistor connection part, and the storage capacitor may extend to overlap the transistor connection part.

[0014] The driving semiconductor layer may extend to overlap the transistor connection portion.

[0015] The transistor connection part may be formed in the same layer as the data line, and may be connected to the compensation source electrode and the light-emitting control source electrode through a contact hole formed in the interlayer insulating film.

[0016] The driving semiconductor layer may further include a branch portion branching from the bent portion.

[0017] The storage capacitor may extend to overlap the branch portion.

[0018] The driving semiconductor layer may include a first path semiconductor layer connected to the compensation thin film transistor and a second path semiconductor layer connected to the light-emitting control thin film transistor, and the length of the first path semiconductor layer may be shorter than the length of the second path semiconductor layer.

[0019] The storage capacitor may extend to overlap the first path semiconductor layer and the second path semiconductor layer.

[0020] The compensation thin film transistor may further include an interlayer insulating film covering the second storage capacitor plate, a connecting member formed on the interlayer insulating film and connected to the first storage capacitor plate through a contact hole formed in the second gate insulating film and the interlayer insulating film, and a passivation film covering the interlayer insulating film and the connecting member, wherein the connecting member is connected to a compensation drain electrode of the compensation thin film transistor.

[0021] The scan lines may be formed in the same layer as the first storage capacitor plates, and the data lines and the driving voltage lines may be formed in the same layer as the connecting members.

[0022] The driving voltage line may be connected to the second storage capacitor plate through a contact hole formed in the interlayer insulating layer.

[0023] The light emitting element may further include an operation control thin film transistor that is turned on by a light emitting control signal transmitted by the light emitting control line to transmit the driving voltage to the driving thin film transistor, and the operation control thin film transistor may be located between the driving voltage line and a driving source electrode of the driving thin film transistor.

[0024] The pixel may further include an initialization thin film transistor that is turned on by a previous scan signal previously transmitted through a scan line and transmits an initialization voltage transmitted through an initialization voltage line to a driving gate electrode of the driving thin film transistor, the initialization thin film transistor being located between the initialization voltage line and the driving gate electrode of the driving thin film transistor.

[0025] The light-emitting element may further include a bypass thin film transistor that bypasses a portion of the driving current transmitted by the driving thin film transistor in response to a bypass control signal transmitted by a bypass control line, and the bypass thin film transistor may be located between the initialization voltage line and an emission control drain electrode of the emission control thin film transistor.

[0026] According to another embodiment of the present invention, an organic light emitting display device includes a substrate, scan lines and initialization voltage lines formed on the substrate for transmitting scan signals and initialization voltages, respectively, data lines and driving voltage lines crossing the scan lines for transmitting data signals and driving voltages, respectively, switching thin film transistors connected to the scan lines and the data lines, a driving thin film transistor connected to a switching drain electrode of the switching thin film transistor, an organic light emitting diode connected to a driving drain electrode of the driving thin film transistor, an emission control thin film transistor positioned between the driving drain electrode of the driving thin film transistor and the organic light emitting diode, and a bypass thin film transistor positioned between the initialization voltage line and an emission control drain electrode of the emission control thin film transistor, wherein the bypass thin film transistor may bypass a portion of a driving current transmitted by the driving thin film transistor in response to a bypass control signal transmitted by a bypass control line.

[0027] The driving semiconductor layer of the driving thin film transistor may be curved.

[0028] The semiconductor device may further include a first gate insulating layer covering the driving semiconductor layer, and a storage capacitor formed on the first gate insulating layer and overlapping the driving semiconductor layer.

[0029] The storage capacitor may include a first storage storage plate formed on the first gate insulating layer and overlapping the driving semiconductor layer, a second gate insulating layer covering the first storage storage plate, and a second storage storage plate formed on the second gate insulating layer and overlapping the first storage storage plate.

[0030] The driving semiconductor layer may include a plurality of bent portions, and the driving semiconductor layer may include a plurality of first extension portions extending in a first direction and a plurality of second extension portions extending in a second direction different from the first direction, and the bent portions may connect the first extension portions and the second extension portions.

[0031] The display device may further include a compensation thin film transistor connected to the driving thin film transistor, for compensating for a threshold voltage of the driving thin film transistor.

[0032] The compensation thin film transistor may further include an interlayer insulating film covering the second storage capacitor plate, a connecting member formed on the interlayer insulating film and connected to the first storage capacitor plate through a contact hole formed in the second gate insulating film and the interlayer insulating film, and a passivation film covering the interlayer insulating film and the connecting member, wherein the connecting member is connected to a compensation drain electrode of the compensation thin film transistor.

[0033] The scan lines may be formed in the same layer as the first storage capacitor plates, and the data lines and driving voltage lines may be formed in the same layer as the connecting members.

[0034] The driving voltage line may be connected to the second storage capacitor plate through a contact hole formed in the interlayer insulating layer. [Effects of the Invention]

[0035] According to the present invention, by forming a driving semiconductor layer including a plurality of bends, the driving channel region of the driving semiconductor layer can be formed long, thereby widening the driving range of the gate voltage applied to the driving gate electrode.

[0036] Therefore, since the driving range of the gate voltage is wide, the magnitude of the gate voltage can be changed to more precisely control the gray scale of the light emitted from the organic light emitting diode (OLED), thereby increasing the resolution of the OLED display and improving the display quality.

[0037] In addition, in order to secure the area of ​​the storage capacitor reduced by the driving semiconductor layer having the bent portion, the storage capacitor is formed overlapping the driving semiconductor layer, thereby ensuring sufficient storage capacitance even at high resolution.

[0038] Furthermore, by forming the length of the first path semiconductor layer connected to the compensation thin film transistor shorter than the length of the second path semiconductor layer connected to the light-emitting control thin film transistor, unevenness in low gradation can be prevented. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is an equivalent circuit diagram of one pixel of an organic light-emitting display device according to a first embodiment of the present invention. [Figure 2] 2 is a diagram illustrating the positions of a plurality of thin film transistors and capacitors in the organic light emitting display device according to the first embodiment of the present invention; FIG. [Figure 3] 2 is a detailed layout diagram of one pixel of the organic light emitting display device according to the first embodiment of the present invention; FIG. [Figure 4] 4 is a cross-sectional view of the organic light-emitting display device of FIG. 3 taken along line IV-IV. [Figure 5] 4 is a cross-sectional view of the organic light-emitting display device of FIG. 3 taken along line VV. [Figure 6] 10 is an enlarged layout view of a driving thin film transistor of an organic light emitting display device according to a second embodiment of the present invention. FIG. [Figure 7] FIG. 10 is a layout diagram of an organic light emitting display device according to a third embodiment of the present invention. [Figure 8] 10 is an enlarged layout view of a driving thin film transistor of an organic light emitting display device according to a fourth embodiment of the present invention. FIG. [Figure 9] 10 is an enlarged layout diagram of a driving thin film transistor of an organic light emitting display device according to a fifth embodiment of the present invention. FIG. [Figure 10] FIG. 10 is an equivalent circuit diagram of one pixel of an organic light-emitting display device according to a sixth embodiment of the present invention. [Figure 11] FIG. 10 is a layout diagram of an organic light emitting display device according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention may be embodied in various different forms and should not be construed as limited to the embodiments set forth herein.

[0041] In order to clearly explain the present invention, parts that are not necessary for the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0042] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown.

[0043] In the drawings, the thicknesses of various layers and regions are exaggerated to clearly show them. Also, in the drawings, the thicknesses of some layers and regions are exaggerated for the convenience of explanation. When a layer, film, region, plate, or other portion is said to be "on" another portion, this does not only mean that it is "directly on" the other portion, but also includes the case where another portion exists between them.

[0044] Furthermore, throughout the specification, when a part "comprises" a certain element, this does not mean excluding other elements, but rather includes the other elements, unless otherwise specified. Furthermore, throughout the specification, the term "on" means being located above or below the target part, and does not necessarily mean being located above the direction of gravity.

[0045] Hereinafter, an organic light emitting display device according to a first embodiment of the present invention will be described in detail with reference to FIGS.

[0046] FIG. 1 is an equivalent circuit diagram of one pixel of an organic light emitting display device according to a first embodiment of the present invention.

[0047] As shown in FIG. 1, one pixel of the organic light emitting display device according to the first embodiment of the present invention includes a plurality of signal lines 121, 122, 123, 124, 171, 172, a plurality of thin film transistors (T1, T2, T3, T4, T5, T6) connected to the plurality of signal lines, a storage capacitor (Cst), and an organic light emitting diode (OLED).

[0048] The thin film transistors include a driving thin film transistor (T1), a switching thin film transistor (T2), a compensation thin film transistor (T3), an initialization thin film transistor (T4), an operation control thin film transistor (T5), and an emission control thin film transistor (T6).

[0049] The signal lines include a scan line 121 for transmitting a scan signal (Sn), a previous scan line 122 for transmitting a previous scan signal (Sn-1) to the initialization thin film transistor (T4), an emission control line 123 for transmitting an emission control signal (En) to the operation control thin film transistor (T5) and the emission control thin film transistor (T6), a data line 171 crossing the scan line 121 for transmitting a data signal (Dm), a driving voltage line 172 for transmitting a driving voltage (ELVDD) and formed approximately parallel to the data line 171, and an initialization voltage line 124 for transmitting an initialization voltage (Vint) for initializing the driving thin film transistor (T1).

[0050] The gate electrode (G1) of the driving thin film transistor (T1) is connected to one end (Cst1) of the storage capacitor (Cst), the source electrode (S1) of the driving thin film transistor (T1) is connected to the driving voltage line 172 via the operation control thin film transistor (T5), and the drain electrode (D1) of the driving thin film transistor (T1) is electrically connected to the anode of the organic light emitting diode (OLED) via the emission control thin film transistor (T6). The driving thin film transistor (T1) receives a data signal (Dm) through the switching operation of the switching thin film transistor (T2) and supplies a driving current (Id) to the organic light emitting diode (OLED).

[0051] The gate electrode (G2) of the switching thin film transistor (T2) is connected to the scan line 121, the source electrode (S2) of the switching thin film transistor (T2) is connected to the data line 171, and the drain electrode (D2) of the switching thin film transistor (T2) is connected to the source electrode (S1) of the driving thin film transistor (T1) and also connected to the driving voltage line 172 via the operation control thin film transistor (T5). The switching thin film transistor (T2) is turned on by the scan signal (Sn) transmitted through the scan line 121 and performs a switching operation of transmitting the data signal (Dm) transmitted to the data line 171 to the source electrode of the driving thin film transistor (T1).

[0052] The gate electrode (G3) of the compensation thin film transistor (T3) is connected to the scan line 121, and the source electrode (S3) of the compensation thin film transistor (T3) is connected to the drain electrode (D1) of the driving thin film transistor (T1) and also to the anode of the organic light emitting diode (OLED) via the emission control thin film transistor (T6). The drain electrode (D3) of the compensation thin film transistor (T3) is connected to one end (Cst1) of the storage capacitor (Cst), the drain electrode (D4) of the initialization thin film transistor (T4), and the gate electrode (G1) of the driving thin film transistor (T1). The compensation thin film transistor (T3) is turned on by the scan signal (Sn) transmitted through the scan line 121 to connect the gate electrode (G1) and drain electrode (D1) of the driving thin film transistor (T1) to each other, thereby diode-connecting the driving thin film transistor (T1).

[0053] The gate electrode (G4) of the initialization thin film transistor (T4) is connected to the previous scan line 122, the source electrode (S4) of the initialization thin film transistor (T4) is connected to the initialization voltage line 124, and the drain electrode (D4) of the initialization thin film transistor (T4) is connected to one end (Cst1) of the storage capacitor (Cst), the drain electrode (D3) of the compensation thin film transistor (T3), and the gate electrode (G1) of the driving thin film transistor (T1). The initialization thin film transistor (T4) is turned on by the previous scan signal (Sn-1) transmitted through the previous scan line 122 to transmit the initialization voltage (Vint) to the gate electrode (G1) of the driving thin film transistor (T1) and perform an initialization operation to initialize the voltage of the gate electrode (G1) of the driving thin film transistor (T1).

[0054] The gate electrode (G5) of the operation control thin film transistor (T5) is connected to the light emitting control line 123, the source electrode (S5) of the operation control thin film transistor (T5) is connected to the driving voltage line 172, and the drain electrode (D5) of the operation control thin film transistor (T5) is connected to the source electrode (S1) of the driving thin film transistor (T1) and the drain electrode (S2) of the switching thin film transistor (T2).

[0055] The gate electrode (G6) of the emission control thin film transistor (T6) is connected to the emission control line 123, the source electrode (S6) of the emission control thin film transistor (T6) is connected to the drain electrode (D1) of the driving thin film transistor (T1) and the source electrode (S3) of the compensation thin film transistor (T3), and the drain electrode (D6) of the emission control thin film transistor (T6) is electrically connected to the anode of the organic light emitting diode (OLED). The operation control thin film transistor (T5) and the emission control thin film transistor (T6) are simultaneously turned on by the emission control signal (En) transmitted through the emission control line 123, and the driving voltage (ELVDD) is transmitted to the organic light emitting diode (OLED), causing a driving current (Id) to flow through the organic light emitting diode (OLED).

[0056] The other end (Cst2) of the storage capacitor (Cst) is connected to the driving voltage line 172, and the cathode of the organic light emitting diode (OLED) is connected to the common voltage (ELVSS). As a result, the organic light emitting diode (OLED) receives the driving current (Id) from the driving thin film transistor (T1) and emits light to display an image.

[0057] Hereinafter, a specific operation process of one pixel of the organic light emitting display device according to the first embodiment of the present invention will be described in detail.

[0058] First, during the initialization period, a low level previous scan signal (Sn-1) is supplied through the previous scan line 122. Then, the initialization thin film transistor T4 is turned on in response to the low level previous scan signal (Sn-1), and an initialization voltage (Vint) is applied from the initialization voltage line 124 to the gate electrode of the driving thin film transistor T1 through the initialization thin film transistor T4, and the driving thin film transistor T1 is initialized by the initialization voltage (Vint).

[0059] Thereafter, during the data programming period, a low level scan signal (Sn) is supplied through the scan line 121. As a result, the switching thin film transistor (T2) and the compensation thin film transistor (T3) are turned on in response to the low level scan signal (Sn).

[0060] At this time, the driving thin film transistor T1 is diode-connected by the turned-on compensation thin film transistor T3 and is forward-biased.

[0061] Then, a compensation voltage (Dm+Vth, where Vth is a negative value) that is reduced by the threshold voltage (Vth) of the driving thin film transistor (T1) based on the data signal (Dm) supplied from the data line 171 is applied to the gate electrode of the driving thin film transistor (T1).

[0062] The drive voltage (ELVDD) and the compensation voltage (Dm+Vth) are applied to both ends of the storage capacitor (Cst), and a charge corresponding to the voltage difference between both ends is stored in the storage capacitor (Cst). After this, the light emitting control signal (En) supplied from the light emitting control line 123 during the light emitting period changes from high level to low level. As a result, during the light emitting period, the operation control thin film transistor (T5) and the light emitting control thin film transistor (T6) are turned on by the low level light emitting control signal (En).

[0063] Subsequently, a driving current (Id) is generated due to the voltage difference between the gate electrode voltage of the driving thin film transistor (T1) and the driving voltage (ELVDD), and the driving current (Id) is supplied to the organic light-emitting diode (OLED) through the light-emitting control thin film transistor (T6). During the light-emitting period, the gate-source voltage (Vgs) of the driving thin film transistor (T1) is maintained at (Dm + Vth) - ELVDD by the storage capacitor (Cst). According to the current-voltage relationship of the driving thin film transistor (T1), the driving current (Id) is proportional to the square of the source-gate voltage minus the threshold voltage (Dm - ELVDD)². Therefore, the driving current (Id) is determined regardless of the threshold voltage (Vth) of the driving thin film transistor (T1).

[0064] Now, the detailed structure of the pixel of the organic light-emitting display device shown in FIG. 1 will be described in detail with reference to FIGS. 2 to 5 together with FIG.

[0065] Figure 2 is a diagram schematically illustrating the positions of a plurality of thin film transistors and capacitors in an organic light emitting display device according to a first embodiment of the present invention. Figure 3 is a detailed layout diagram of one pixel in an organic light emitting display device according to a first embodiment of the present invention. Figure 4 is a cross-sectional view of the organic light emitting display device of Figure 3 taken along line IV-IV. Figure 5 is a cross-sectional view of the organic light emitting display device of Figure 3 taken along line VV.

[0066] As shown in FIGS. 2 to 5, a pixel of the organic light emitting display device according to the first embodiment of the present invention includes scan lines 121, previous scan lines 122, emission control lines 123, and initialization voltage lines 124 that are formed along the row direction and apply scan signals (Sn), previous scan signals (Sn-1), emission control signals (En), and initialization voltages (Vint), respectively, and also includes data lines 171 and driving voltage lines 172 that intersect with the scan lines 121, previous scan lines 122, emission control lines 123, and initialization voltage lines 124 and apply data signals (Dm) and driving voltages (ELVDD) to the pixel, respectively.

[0067] The pixel also includes a driving thin film transistor (T1), a switching thin film transistor (T2), a compensation thin film transistor (T3), an initialization thin film transistor (T4), an operation control thin film transistor (T5), an emission control thin film transistor (T6), a storage capacitor (Cst), or an organic light emitting diode (OLED) 70.

[0068] The driving thin film transistor (T1), switching thin film transistor (T2), compensation thin film transistor (T3), initialization thin film transistor (T4), operation control thin film transistor (T5), and light-emitting control thin film transistor (T6) are formed along the semiconductor layer 131, which is formed to have various curved shapes. The semiconductor layer 131 is made of polysilicon and includes a channel region that is not doped with impurities, and source and drain regions that are doped with impurities on both sides of the channel region. Here, the impurities vary depending on the type of thin film transistor, but can be N-type or P-type impurities. Such semiconductor layers include a driving semiconductor layer 131a formed in the driving thin film transistor (T1), a switching semiconductor layer 131b formed in the switching thin film transistor (T2), a compensation semiconductor layer 131c formed in the compensation thin film transistor (T3), an initialization semiconductor layer 131d formed in the initialization thin film transistor (T4), an operation control semiconductor layer 131e formed in the operation control thin film transistor (T5), and an emission control semiconductor layer 131f formed in the emission control thin film transistor (T6).

[0069] The driving thin film transistor (T1) includes a driving semiconductor layer 131a, a driving gate electrode 125a, a driving source electrode 176a, and a driving drain electrode 177a. The driving semiconductor layer 131a is curved. The driving semiconductor layer 131a includes a plurality of first extensions 31 extending in a first direction, a plurality of second extensions 32 extending in a second direction different from the first direction, and a plurality of bent portions 33 connecting the first extensions 31 and the second extensions 32. Therefore, the driving semiconductor layer 131a may be arranged in a zigzag shape. The driving semiconductor layer 131a shown in FIGS. 2 and 3 includes three first extensions 31, two second extensions 32, and four bent portions 33. Therefore, the driving semiconductor layer 131a is arranged in a zigzag shape.

[0070] By forming the driving semiconductor layer 131a including the plurality of bent portions 33 in this manner, the driving semiconductor layer 131a can be formed long in a narrow space. Therefore, the driving channel region 131a1 of the driving semiconductor layer 131a can be formed long, and the driving range of the gate voltage applied to the driving gate electrode 125a is wide. Therefore, since the driving range of the gate voltage is wide, the magnitude of the gate voltage can be changed to more precisely control the gray scale of light emitted from the organic light emitting diode (OLED), thereby increasing the resolution of the OLED display and improving display quality.

[0071] The driving semiconductor layer 131a may have various shapes such as "S", "M", and "W" by arranging the first extension 31, the second extension 32, and the bent portion 33 in various ways.

[0072] FIG. 6 is an enlarged layout view of a driving thin film transistor of an organic light emitting display device according to a second embodiment of the present invention.

[0073] As shown in FIG. 6, the driving semiconductor layers 131a may be arranged in an "S" shape.

[0074] Meanwhile, the driving source electrode 176a corresponds to the driving source region 176a doped with impurities in the driving semiconductor layer 131a, and the driving drain electrode 177a corresponds to the driving drain region 177a doped with impurities in the driving semiconductor layer 131a. A storage capacitor Cst is formed on and overlaps the driving gate electrode 125a.

[0075] The storage capacitor Cst includes a first storage storage plate 125a and a second storage storage plate 127 disposed with a second gate insulating layer 142 therebetween. Here, the driving gate electrode 125a also functions as the first storage storage plate 125a, and the second gate insulating layer 142 serves as a dielectric. The storage capacitance is determined by the charge stored in the storage capacitor Cst and the voltage between the two storage plates 125a and 127.

[0076] The first storage capacitor plate 125a is formed in a rectangular shape, separated from adjacent pixels, and is formed in the same layer and made of the same material as the scan line 121, the previous scan line 122, the emission control line 123, the switching gate electrode 125b, the compensation gate electrode 125c, the operation control gate electrode 125e, and the emission control gate electrode 125f.

[0077] The second storage capacitor plate 127 is connected to an adjacent pixel and is formed in the same layer as the initialization voltage line 124 using the same material.

[0078] In this way, in order to secure the area of ​​the storage capacitor reduced by the driving semiconductor layer 131a having the bent portion, the storage capacitor is formed overlapping the driving semiconductor layer 131a, thereby making it possible to secure the storage capacitance even at high resolution.

[0079] The switching thin film transistor T2 includes a switching semiconductor layer 131b, a switching gate electrode 125b, a switching source electrode 176b, and a switching drain electrode 177b. The switching source electrode 176b is a portion protruding from the data line 171, and the switching drain electrode 177b corresponds to a switching drain region 177b doped with impurities in the switching semiconductor layer 131b.

[0080] The compensation thin film transistor T3 includes a compensation semiconductor layer 131c, a compensation gate electrode 125c, a compensation source electrode 176c, and a compensation drain electrode 177c, where the compensation source electrode 176c corresponds to the compensation source region 176c doped with impurities in the compensation semiconductor layer 131c, and the compensation drain electrode 177c corresponds to the compensation drain region 177c doped with impurities in the compensation semiconductor layer 131c. The compensation gate electrode 125c forms a separate dual gate electrode 25 to prevent leakage current.

[0081] The initialization thin film transistor T4 includes an initialization semiconductor layer 131d, an initialization gate electrode 125d, an initialization source electrode 176d, and an initialization drain electrode 177d. The initialization drain electrode 177d corresponds to an initialization drain region 177d doped with impurities in the initialization semiconductor layer 131d. The initialization source electrode 176d is connected to the initialization voltage line 124 through an initialization connection line 78. One end of the initialization connection line 78 is connected to the initialization voltage line 124 through a contact hole 161 formed in the second gate insulating film 142 and the interlayer insulating film 160, and the other end of the initialization connection line 78 is connected to the initialization source electrode 176d through the contact hole 161 formed in the gate insulating film 141, the second gate insulating film 142, and the interlayer insulating film 160.

[0082] The operation control thin film transistor T5 includes an operation control semiconductor layer 131e, an operation control gate electrode 125e, an operation control source electrode 176e, and an operation control drain electrode 177e. The operation control source electrode 176e is a part of the driving voltage line 172, and the operation control drain electrode 177e corresponds to an operation control drain region 177e doped with impurities in the operation control semiconductor layer 131e.

[0083] The light-emission control thin film transistor (T6) includes an light-emission control semiconductor layer 131f, an light-emission control gate electrode 125f, an light-emission control source electrode 176f, and an light-emission control drain electrode 177f. The light-emission control source electrode 176f corresponds to the light-emission control source region 176f doped with impurities in the light-emission control semiconductor layer 131f.

[0084] One end of the driving semiconductor layer 131a of the driving thin film transistor T1 is connected to the switching semiconductor layer 131b and the compensation semiconductor layer 131c, and the other end of the driving semiconductor layer 131a is connected to the operation control semiconductor layer 131e and the emission control semiconductor layer 131f. Therefore, the driving source electrode 176a is connected to the switching drain electrode 177b and the operation control drain electrode 177e, and the driving drain electrode 177a is connected to the compensation source electrode 176c and the emission control source electrode 176f.

[0085] The first storage capacitor plate 125a of the storage capacitor Cst is connected to the compensation drain electrode 177c and the initialization drain electrode 177d through a connecting member 174. The connecting member 174 is formed in the same layer as the data line 171, and one end of the connecting member 174 is connected to the compensation drain electrode 177c and the initialization drain electrode 177d through a contact hole 166 formed in the first gate insulating layer 141, the second gate insulating layer 142, and the interlayer insulating layer 160, and the other end of the connecting member 174 is connected to the first storage capacitor plate 125a through a contact hole 167 formed in the second gate insulating layer 142 and the interlayer insulating layer 160. In this case, the other end of the connecting member 174 is connected to the first storage capacitor plate 125a through a storage opening 27 formed in the second storage capacitor plate 127.

[0086] The second storage capacitor plate 127 of the storage capacitor Cst is connected to the common voltage line 172 through a contact hole 168 formed in the interlayer insulating film 160 .

[0087] Meanwhile, the switching thin film transistor T2 is used as a switching element to select a pixel to be made to emit light. The switching gate electrode 125b is connected to the scan line 121, the switching source electrode 176b is connected to the data line 171, and the switching drain electrode 177b is connected to the driving thin film transistor T1 and the operation control thin film transistor T5. In addition, the emission control drain electrode 177f of the emission control thin film transistor T6 is directly connected to the pixel electrode 191 of the organic light emitting diode 70 through a contact hole 181 formed in the passivation film 180.

[0088] Hereinafter, the structure of the organic light emitting display device according to the first embodiment of the present invention will be described in detail in accordance with the order of lamination with reference to FIGS.

[0089] Here, the structure of the thin film transistors will be described focusing on the driving thin film transistor T1, the switching thin film transistor T2, and the light-emitting control thin film transistor T6. The remaining thin film transistors T3, T4, and T5 have almost the same stacked structure as the driving thin film transistor T1, the switching thin film transistor T2, and the light-emitting control thin film transistor T6, so detailed description thereof will be omitted.

[0090] A buffer layer 111 is formed on a substrate 110, which is made of an insulating material such as glass, quartz, ceramic, or plastic.

[0091] A driving semiconductor layer 131a, a switching semiconductor layer 131b, and an emission control semiconductor layer 131f are formed on the buffer layer 111. The driving semiconductor layer 131a includes a driving channel region 131a1, and a driving source region 176a and a driving drain region 177a that face each other with the driving channel region 131a1 therebetween, the switching semiconductor layer 131b includes a switching channel region 131b1, and a switching source region 132b and a switching drain region 177b that face each other with the switching channel region 131b1 therebetween, and the emission control thin-film transistor (T6) includes an emission control channel region 131f1, an emission control source region 176f, and an emission control drain region 133f.

[0092] The driving semiconductor layer 131a includes multiple bends 33 and is formed in a zigzag shape, specifically in a "V" shape, so that it can be formed long in a narrow space. Therefore, the driving channel region 131a1 of the driving semiconductor layer 131a can be formed long, and the driving range of the gate voltage applied to the driving gate electrode 125a is widened.

[0093] A first gate insulating film 141 made of silicon nitride (SiNx), silicon oxide (SiO2), or the like is formed on the switching semiconductor layer 131a, the driving semiconductor layer 131b, and the light emission control semiconductor layer 131f.

[0094] On the first gate insulating film 141, first gate wiring is formed, including a scan line 121 including a driving gate electrode 125a, a switching gate electrode 125b, and a compensation gate electrode 125c, a previous scan line 122 including an initialization gate electrode 125d, and an emission control line 123 including an operation control gate electrode 125e and an emission control gate electrode 125f.

[0095] The driving gate electrode 125a is separated from the scan line 121, and the floating gate electrode 25 overlaps with the driving channel region 131a1 of the driving semiconductor layer 131a. The switching gate electrode 125a is connected to the scan line 121, and the switching gate electrode 125b overlaps with the switching channel region 131b1 of the switching semiconductor layer 131b. The emission control gate electrode 125f overlaps with the emission control channel region 131f1 of the emission control semiconductor layer 131f.

[0096] In this case, the switching thin film transistor (T2) is capable of rapid switching operation because only the first gate insulating film 141 is formed between the switching gate electrode 125b and the switching semiconductor layer 131b, and the driving thin film transistor (T1) is capable of rapid switching operation because only the first gate insulating film 141 is formed between the driving gate electrode 125a and the driving semiconductor layer 131a but the driving channel region 131a1 of the driving semiconductor layer 131a is long, so the driving range of the gate voltage applied to the driving gate electrode 125a is widened, and the gradation of light emitted from the organic light emitting diode (OLED) can be controlled more precisely.

[0097] The first gate wirings 125a, 125b, 125c, 125d, 125e, 125f, 121, 122, and 123 and the first gate insulating film 141 are covered with a second gate insulating film 142. The second gate insulating film 142 is made of silicon nitride (SiNx), silicon oxide (SiO2), or the like.

[0098] A second gate wiring including a second storage capacitor plate 127 and an initialization voltage line 124 is formed on the second gate insulating film 142. The second storage capacitor plate 127 overlaps with the first storage capacitor plate 125a to form a storage capacitor (Cst), and the first storage capacitor plate 125a overlaps with the driving semiconductor layer 131a. By forming the storage capacitor (Cst) overlapping with the driving semiconductor layer 131a in this manner, the area of ​​the storage capacitor (Cst) that would have been reduced by the driving semiconductor layer 131a having the bent portion 33 is secured, and storage capacitance can be secured even at high resolutions where pixel size is reduced.

[0099] Meanwhile, an interlayer insulating film 160 is formed on the second gate insulating film 142, the second storage capacitor plate 127, and the initialization voltage line 124. The first gate insulating film 141, the second gate insulating film 142, and the interlayer insulating film 160 all have a contact hole 163 that exposes the emission control drain region 131f1 of the emission control semiconductor layer 131f. The interlayer insulating film 160, like the first gate insulating film 141 and the second gate insulating film 142, is made of a ceramic-based material such as silicon nitride (SiNx) or silicon oxide (SiO2).

[0100] On the interlayer insulating film 160, a data line 171 including a switching source electrode 176b, a driving voltage line 172, a connecting member 174, and a data wiring including a light-emitting control drain electrode 177f are formed.

[0101] In addition, the switching source electrode 176b and the emission control drain electrode 177f are respectively connected to the switching source region 131b1 of the switching semiconductor layer 131b and the emission control drain region 131f1 of the emission control semiconductor layer 131f through contact holes 162 and 163 formed in the interlayer insulating film 160, the first gate insulating film 141, and the second gate insulating film 142.

[0102] A passivation layer 180 covering the data lines 171, 172, 174, and 177f is formed on the interlayer insulating film 160, and a pixel electrode 191 is formed on the passivation layer 180. The pixel electrode 191 is connected to the emission control drain electrode 177f through a contact hole 181 formed in the passivation layer 180.

[0103] A partition 350 is formed around the periphery of the pixel electrode 191 and on the protective film 180, and the partition 350 has a partition opening 351 that exposes the pixel electrode 191. The partition 350 may be made of a resin such as a polyacrylate resin or a polyimide, or a silica-based inorganic material.

[0104] An organic light-emitting layer 370 is formed on the pixel electrode 191 exposed through the partition opening 351, and a common electrode 270 is formed on the organic light-emitting layer 370. In this manner, an organic light-emitting diode 70 including the pixel electrode 191, the organic light-emitting layer 370, and the common electrode 270 is formed.

[0105] Here, pixel electrode 191 is an anode of a hole injection electrode, and common electrode 270 is a cathode of an electron injection electrode. However, an embodiment according to the present invention is not limited to this, and pixel electrode 191 may be a cathode and common electrode 270 may be an anode depending on a driving method of the OLED display. Holes and electrons are injected into organic light-emitting layer 370 from pixel electrode 191 and common electrode 270, respectively, and light is emitted when excitons formed by combining the injected holes and electrons fall from an excited state to a ground state.

[0106] The organic light-emitting layer 370 is made of a low-molecular-weight organic material or a polymer organic material such as PEDOT (Poly 3,4-ethylenedioxythiophene). The organic light-emitting layer 370 may also be formed as a multilayer including an emitting layer and one or more of a hole injection layer (HIL), a hole transporting layer (HTL), an electron transporting layer (ETL), and an electron injection layer (EIL). When all of these are included, the hole injection layer is disposed on the positive pixel electrode 710, and the hole transport layer, emitting layer, electron transport layer, and electron injection layer are sequentially stacked thereon. The common electrode 270 is formed of a reflective conductive material, resulting in a bottom-emission organic light-emitting display device. The reflective material may be lithium (Li), calcium (Ca), lithium / calcium fluoride (LiF / Ca), lithium / aluminum fluoride (LiF / Al), aluminum (Al), silver (Ag), magnesium (Mg), or gold (Au).

[0107] Meanwhile, in the first embodiment, the first storage capacitor plate 125a has a rectangular shape, but a third embodiment is also possible in which a portion of the first storage capacitor plate 125a is expanded to increase the storage capacitance.

[0108] Hereinafter, the organic light emitting display device according to the third embodiment of the present invention will be described in detail with reference to FIG.

[0109] FIG. 7 is a layout diagram of an organic light emitting display device according to a third embodiment of the present invention.

[0110] The third embodiment is substantially the same as the first embodiment shown in FIGS. 1 to 5 except for the driving semiconductor layer and the storage capacitor, and therefore, a repeated description will be omitted.

[0111] 7, the driving thin film transistor (T1) of the organic light emitting display device according to the third embodiment of the present invention includes a driving semiconductor layer 131a, a driving gate electrode 125a, a driving source electrode 176a, and a driving drain electrode 177a. The driving semiconductor layer 131a is curved. The driving semiconductor layer 131a includes a plurality of first extensions 31 extending in a first direction, a plurality of second extensions 32 extending in a second direction different from the first direction, and a plurality of bent portions 33 connecting the first extensions 31 and the second extensions 32.

[0112] The driving semiconductor layer 131a may extend laterally to be adjacent to the data line 171. As a result, the driving semiconductor layer 131a is longer, which can further widen the driving range of the gate voltage applied to the driving gate electrode 125a.

[0113] At this time, the compensation source electrode 176c of the compensation thin film transistor (T3) and the emission control source electrode 176f of the emission control thin film transistor (T6) are formed in the same layer, but the compensation source electrode 176c and the emission control source electrode 176f are separated from each other by a separation portion (d) so as not to overlap with the driving semiconductor layer 131a.

[0114] The driving gate electrode 125a, i.e., the first storage capacitor plate 125a, extends laterally to overlap the extended driving semiconductor layer 131a, and the first storage capacitor plate 125a partially overlaps the separated portion (d). The second storage capacitor plate 127 also extends laterally to overlap the first storage capacitor plate 125a, and the second storage capacitor plate 127 partially overlaps the separated portion (d).

[0115] The compensation source electrode 176c and the emission control source electrode 176f, which are separated from each other, are connected through a transistor connector 71 formed in the same layer as the data line 171. One end of the transistor connector 71 is connected to the compensation source electrode 176c through a contact hole 61 formed in the first gate insulating film 141, the second gate insulating film 142, and the interlayer insulating film 160, and the other end of the transistor connector 71 is connected to the emission control source electrode 176f through a contact hole 62 formed in the first gate insulating film 141, the second gate insulating film 142, and the interlayer insulating film 160. Therefore, the storage capacitor Cct extends to overlap the transistor connector 71, and the driving semiconductor layer 131a extends to overlap the transistor connector 71.

[0116] In this manner, by connecting the compensation source electrode 176c and the light-emitting control source electrode 176f through the transistor connection part 71, the driving semiconductor layer 131a, the first storage capacitor plate 125a, and the second storage capacitor plate 127 can be extended to the separation part (d) between the compensation source electrode 176c and the light-emitting control source electrode 176f, thereby further expanding the storage capacitor (Cst).

[0117] Meanwhile, in the first embodiment, the driving semiconductor layer is not directly connected to the compensation source electrode at the bent portion, but a fourth embodiment may be possible in which the driving semiconductor layer further includes a branch portion that branches directly to the compensation source electrode at the bent portion.

[0118] Hereinafter, the organic light emitting display device according to the fourth embodiment of the present invention will be described in detail with reference to FIG.

[0119] FIG. 8 is an enlarged layout view of a driving thin film transistor of an organic light emitting display device according to a fourth embodiment of the present invention.

[0120] The fourth embodiment is substantially the same as the first embodiment shown in FIGS. 1 to 5 except for the driving semiconductor layer and the storage capacitor, and therefore, a repeated description will be omitted.

[0121] As shown in FIG. 8, the driving thin film transistor T1 of the organic light emitting display device according to the fourth embodiment of the present invention includes a driving semiconductor layer 131a, a driving gate electrode 125a, a driving source electrode 176a, and a driving drain electrode 177a. The driving semiconductor layer 131a is curved. The driving semiconductor layer 131a includes a first extension 31 extending in a first direction, a second extension 32 extending in a second direction different from the first direction, a bent portion 33 connecting the first extension 31 and the second extension 32, and a branch portion 34 branching directly from the bent portion to the compensation source electrode 176c. The driving semiconductor layer 131a has an overall "┤" shape (the opposite shape of a "T"). Since the length of the driving semiconductor layer 131a is increased, the driving range of the gate voltage applied to the driving gate electrode 125a can be further widened.

[0122] The branch portion 34 corresponds to a first path semiconductor layer CH1 connected to the compensation thin film transistor T3, and the second extension portion 32 corresponds to a second path semiconductor layer CH2 connected to the light-emitting control thin film transistor T6. In addition, the driving gate electrode, i.e., the first storage capacitor plate 125a, overlaps the first path semiconductor layer CH1 and the second path semiconductor layer CH2 of the driving semiconductor layer 131a, and the second storage capacitor plate 127 overlaps the first storage capacitor plate 125a. Therefore, the area of ​​the storage capacitor Cst is increased, making it easy to ensure storage capacitance even at high resolution.

[0123] Meanwhile, in the fourth embodiment, the lengths of the first path semiconductor layer (CH1) and the second path semiconductor layer (CH2) are the same, but a fifth embodiment is also possible in which the lengths of the first path semiconductor layer (CH1) and the second path semiconductor layer (CH2) are different from each other.

[0124] Hereinafter, the organic light emitting display device according to the fifth embodiment of the present invention will be described in detail with reference to FIG.

[0125] FIG. 9 is an enlarged layout view of a driving thin film transistor of an organic light emitting display device according to a fifth embodiment of the present invention.

[0126] The fifth embodiment is substantially the same as the fourth embodiment shown in FIG. 8 except for the driving semiconductor layer and the storage capacitor, and therefore, a repeated description will be omitted.

[0127] 9, the driving thin film transistor T1 of the organic light emitting display device according to the fifth embodiment of the present invention includes a driving semiconductor layer 131a, a driving gate electrode 125a, a driving source electrode 176a, and a driving drain electrode 177a. The driving semiconductor layer 131a is curved. The driving semiconductor layer 131a includes a first extension 31 extending in a first direction, a second extension 32 extending in a second direction different from the first direction, a bent portion 33 connecting the first extension 31 and the second extension 32, and a branch portion 34 branching from the bent portion to a compensation source electrode 176c. Since the length of the driving semiconductor layer 131a is increased, the driving range of the gate voltage applied to the driving gate electrode 125a can be further widened.

[0128] The branch portion 34 corresponds to the first path semiconductor layer CH1 connected to the compensation thin film transistor T3, and the zigzag portion 30 including the first extension portion 31, the second extension portion 32, and the bent portion 33 corresponds to the second path semiconductor layer CH2 connected to the light-emitting control thin film transistor T6. In addition, the driving gate electrode, i.e., the first storage capacitor plate 125a, overlaps the first path semiconductor layer CH1 and the second path semiconductor layer CH2 of the driving semiconductor layer 131a, and the second storage capacitor plate 127 overlaps the first storage capacitor plate 125a. Therefore, the area of ​​the storage capacitor Cst is increased, making it easy to ensure storage capacitance even at high resolution.

[0129] The length of the first path semiconductor layer (CH1) is shorter than the length of the second path semiconductor layer (CH2). This structure is called a short pass diode structure, and because the lengths of the first path semiconductor layer (CH1) and the second path semiconductor layer (CH2) are different, currents of different magnitudes flow simultaneously. Because the length of the first path semiconductor layer (CH1) is short, a relatively large current flows, and because the length of the second path semiconductor layer (CH2) is long, a relatively small current flows simultaneously. By utilizing the feature of being able to simultaneously provide currents of different magnitudes to one driving thin film transistor, it is possible to quickly compensate for the threshold voltage and provide a constant current to the OLED, thereby reducing the current deviation between driving thin film transistors with characteristic deviations and preventing unevenness due to differences in current magnitude. This driving operation will be described in detail below.

[0130] The driving thin film transistor (T1) charges the storage capacitor (Cst) with a voltage corresponding to the data signal (Dm) according to the scan signal (Sn), and provides the organic light emitting diode (OLED) with a current corresponding to the voltage charged in the storage capacitor (Cst). At this time, since the threshold voltage of the driving thin film transistor (T1) may change over time, the compensating thin film transistor (T3) diode-connects the driving thin film transistor (T1) according to the scan signal (Sn) and compensates for the threshold voltage (Vth) of the driving thin film transistor (T1).

[0131] Therefore, while the data signal (Dm) is being transmitted, a relatively large current flowing through the first path semiconductor layer (CH1) can quickly charge the storage capacitor (Cst) to a predetermined voltage (compensation voltage) through the compensation thin film transistor (T3), thereby allowing threshold voltage (Vth) compensation to be performed quickly and easily.

[0132] In addition, since a relatively small current flowing through the second path semiconductor layer CH2 is provided to the organic light emitting diode (OLED) through the light emitting control thin film transistor T6, unevenness can be prevented. That is, since the rate of change of current due to a change in voltage applied to the driving gate electrode of the driving thin film transistor T1 is small, the current control voltage range (data swing range) can be increased, thereby increasing the range of data voltages expressing gamma. Furthermore, since the current deviation between driving thin film transistors having characteristic deviation (scatter) is reduced, unevenness due to differences in current magnitude can be prevented.

[0133] A conventional driving thin film transistor (TFT) allows only one magnitude of current to flow through the driving semiconductor layer 131a, and therefore provides the same magnitude of current to the compensation thin film transistor (T3) and the light-emitting control thin film transistor (T6). If the driving semiconductor layer 131a of the driving thin film transistor (T1) is shortened to quickly compensate for the threshold voltage (Vth) of the driving thin film transistor (T1), the s-factor of the transistor transfer curve decreases and the rate of change in current due to a change in voltage applied to the driving gate electrode increases, resulting in a large current being provided to the organic light-emitting diode (OLED), causing unevenness.

[0134] On the other hand, if the driving semiconductor layer 131a of the driving thin film transistor T1 is made longer to prevent unevenness, compensation of the threshold voltage (Vth) of the driving thin film transistor is delayed due to a small current, and low gray scale compensation is not performed, resulting in unevenness. This problem becomes more serious as the resolution increases. That is, as the resolution increases, the time for applying the data signal (Dm) decreases, so current flows to the organic light emitting diode (OLED) before the threshold voltage (Vth) is fully compensated, which causes current deviation and results in unevenness.

[0135] Therefore, by forming the length of the first path semiconductor layer (CH1) connected to the compensation thin film transistor (T3) shorter than the length of the second path semiconductor layer (CH2) connected to the light-emitting control thin film transistor (T6), it is possible to prevent low-level gradation unevenness.

[0136] Meanwhile, the first embodiment has a 6tr 1cap structure consisting of six thin film transistors and one storage capacitor, in which the driving semiconductor layer of the driving thin film transistor is bent. However, a sixth embodiment is also possible, in which the driving semiconductor layer of the driving thin film transistor is bent, in which the driving semiconductor layer of the driving thin film transistor is bent, in which the driving semiconductor layer of the driving thin film transistor is bent, in which the driving semiconductor layer of the driving thin film transistor is bent.

[0137] Hereinafter, the organic light emitting display device according to the sixth embodiment of the present invention will be described in detail with reference to FIGS.

[0138] 10 and 11 are equivalent circuit diagrams of one pixel of an organic light emitting display device according to a sixth embodiment of the present invention, respectively.

[0139] The sixth embodiment is substantially the same as the first embodiment shown in FIGS. 1 to 5 except that a current control thin film transistor is added, and therefore a repeated description will be omitted.

[0140] As shown in FIGS. 10 and 11, one pixel of the organic light emitting display device according to the sixth embodiment of the present invention includes a plurality of signal lines 121, 122, 123, 124, 128, 171, 172, a plurality of thin film transistors (T1, T2, T3, T4, T5, T6, T7) connected to the plurality of signal lines, a storage capacitor (Cst), and an organic light emitting diode (OLED).

[0141] The thin film transistors include a driving thin film transistor (T1), a switching thin film transistor (T2), a compensation thin film transistor (T3), an initialization thin film transistor (T4), an operation control thin film transistor (T5), a light-emitting control thin film transistor (T6), and a current control thin film transistor (T7).

[0142] The signal lines include a scan line 121 transmitting a scan signal (Sn), a previous scan line 122 transmitting a previous scan signal (Sn-1) to the initialization thin film transistor (T4), an emission control line 123 transmitting an emission control signal (En) to the operation control thin film transistor (T5) and the emission control thin film transistor (T6), a data line 171 crossing the scan line 121 and transmitting a data signal (Dm), a driving voltage line 172 transmitting a driving voltage (ELVDD) and formed approximately parallel to the data line 171, an initialization voltage line 124 transmitting an initialization voltage (Vint) to initialize the driving thin film transistor (T1), and a bypass control line 128 transmitting a bypass signal (BP) to the bypass thin film transistor (T7).

[0143] The gate electrode (G1) of the driving thin film transistor (T1) is connected to one end (Cst1) of the storage capacitor (Cst), the source electrode (S1) of the driving thin film transistor (T1) is connected to the driving voltage line 172 via the operation control thin film transistor (T5), and the drain electrode (D1) of the driving thin film transistor (T1) is electrically connected to the anode of the organic light emitting diode (OLED) via the emission control thin film transistor (T6).

[0144] The gate electrode (G2) of the switching thin film transistor (T2) is connected to the scan line 121, the source electrode (S2) of the switching thin film transistor (T2) is connected to the data line 171, and the drain electrode (D2) of the switching thin film transistor (T2) is connected to the source electrode (S1) of the driving thin film transistor (T1) and is also connected to the driving voltage line 172 via the operation control thin film transistor (T5).

[0145] The gate electrode (G4) of the initialization thin film transistor (T4) is connected to the previous scan line 122, the source electrode (S4) of the initialization thin film transistor (T4) is connected to the initialization voltage line 124, and the drain electrode (D4) of the initialization thin film transistor (T4) is connected to one end (Cst1) of the storage capacitor (Cst), the drain electrode (D3) of the compensation thin film transistor (T3), and the gate electrode (G1) of the driving thin film transistor (T1).

[0146] The gate electrode (G7) of the bypass thin film transistor (T7) is connected to the bypass control line 128, the source electrode (S7) of the bypass thin film transistor (T7) is connected to the drain electrode (D6) of the light-emitting control thin film transistor (T6) and the anode of the organic light-emitting diode (OLED), and the drain electrode (D7) of the bypass thin film transistor (T7) is connected to the initialization voltage line 124 and the source electrode (S4) of the initialization thin film transistor (T4).

[0147] Hereinafter, a specific operation process of the bypass thin film transistor T7 of the organic light emitting display device according to the sixth embodiment of the present invention will be described in detail.

[0148] The bypass thin film transistor T7 receives a bypass signal BP from a bypass control line 128. The bypass signal BP is a voltage of a predetermined level that can keep the bypass thin film transistor T7 always off, and the bypass thin film transistor T7 is always off when a transistor off level voltage is transmitted to the gate electrode G7, and in the off state, a part of the driving current Id flows out through the bypass transistor T7 as a bypass current Ibp.

[0149] Even if the minimum current of the driving thin film transistor (TFT) for displaying a black image flows as a driving current, the black image will not be displayed properly if the organic light emitting diode (OLED) emits light. Therefore, the bypass thin film transistor (T7) of the organic light emitting display device according to the sixth embodiment of the present invention distributes a portion of the minimum current of the driving thin film transistor (T1) as a bypass current (Ibp) to a current path other than the current path toward the OLED. Here, the minimum current of the driving thin film transistor refers to the current under the condition that the gate-source voltage (Vgs) of the driving thin film transistor is lower than the threshold voltage (Vth) and the driving thin film transistor is turned off. In this way, the minimum driving current (e.g., a current of 10 pA or less) under the condition that the driving thin film transistor is turned off is transmitted to the OLED, thereby displaying a black image.

[0150] When a minimum driving current for displaying a black image flows, the influence of the clockwise transmission of the bypass current (Ibp) is large, but when a large driving current for displaying an image such as a normal image or a white image flows, the influence of the bypass current (Ibp) is almost negligible. Therefore, when a driving current for displaying a black image flows, the light-emitting current (Ioled) of the OLED, which is reduced by the amount of the bypass current (Ibp) leaked from the driving current (Id) through the bypass thin film transistor (T7), has a minimum current amount at a level that can reliably display a black image.

[0151] Therefore, by using the bypass thin film transistor, accurate black luminance images can be realized and the contrast ratio can be improved.

[0152] Hereinafter, the detailed structure of the pixel of the organic light emitting display device shown in FIG. 10 will be described in detail with reference to FIG. 11 in conjunction with FIG. 10 and FIG.

[0153] FIG. 11 is a layout diagram of an organic light emitting display device according to a sixth embodiment of the present invention.

[0154] As shown in FIGS. 10 and 11, a pixel of the organic light emitting display device according to the sixth embodiment of the present invention includes scan lines 121, previous scan lines 122, emission control lines 123, initialization voltage lines 124, and bypass control lines 128 that are formed along the row direction and apply scan signals (Sn), previous scan signals (Sn-1), emission control signals (En), and initialization voltages (Vint), respectively, and also includes data lines 171 and driving voltage lines 172 that intersect with the scan lines 121, previous scan lines 122, emission control lines 123, initialization voltage lines 124, and bypass control lines 128 and apply data signals (Dm) and driving voltages (ELVDD) to the pixels, respectively.

[0155] In addition, the pixel includes a driving thin film transistor (T1), a switching thin film transistor (T2), a compensation thin film transistor (T3), an initialization thin film transistor (T4), an operation control thin film transistor (T5), an emission control thin film transistor (T6), a bypass thin film transistor (T7), a storage capacitor (Cst), or an organic light emitting diode (OLED) 70.

[0156] The driving thin film transistor (T1), switching thin film transistor (T2), compensation thin film transistor (T3), initialization thin film transistor (T4), operation control thin film transistor (T5), light-emitting control thin film transistor (T6), and bypass thin film transistor (T7) are formed along the semiconductor layer 131, which is curved in various shapes. The semiconductor layer 131 is made of polysilicon and includes a channel region that is not doped with impurities, and source and drain regions that are doped with impurities on both sides of the channel region. Here, the impurities vary depending on the type of thin film transistor, but can be N-type or P-type impurities. Such semiconductor layers include a driving semiconductor layer 131a formed in the driving thin film transistor (T1), a switching semiconductor layer 131b formed in the switching thin film transistor (T2), a compensation semiconductor layer 131c formed in the compensation thin film transistor (T3), an initialization semiconductor layer 131d formed in the initialization thin film transistor (T4), an operation control semiconductor layer 131e formed in the operation control thin film transistor (T5), an emission control semiconductor layer 131f formed in the emission control thin film transistor (T6), and a bypass semiconductor layer 131g formed in the bypass thin film transistor (T7).

[0157] The driving thin film transistor (T1) includes a driving semiconductor layer 131a, a driving gate electrode 125a, a driving source electrode 176a, and a driving drain electrode 177a. The driving semiconductor layer 131a is curved. The driving semiconductor layer 131a includes a plurality of first extensions 31 extending in a first direction, a plurality of second extensions 32 extending in a second direction different from the first direction, and a plurality of bent portions 33 connecting the first extensions 31 and the second extensions 32. Therefore, the driving semiconductor layer 131a is arranged in a zigzag shape. The driving semiconductor layer 131a shown in FIGS. 2 and 3 includes three first extensions 31, two second extensions 32, and four bent portions 33. Therefore, the driving semiconductor layer 131a is arranged in a zigzag shape.

[0158] By forming the driving semiconductor layer 131a including the plurality of bent portions 33 in this manner, the driving semiconductor layer 131a can be formed long in a narrow space. Therefore, the driving channel region 131a1 of the driving semiconductor layer 131a can be formed long, and the driving range of the gate voltage applied to the driving gate electrode 125a is wide. Therefore, since the driving range of the gate voltage is wide, the magnitude of the gate voltage can be changed to more precisely control the gray scale of light emitted from the organic light emitting diode (OLED), thereby increasing the resolution of the OLED display and improving display quality.

[0159] The bypass thin film transistor T7 includes a bypass semiconductor layer 131g, a bypass gate electrode 125g, a bypass source electrode 176g, and a bypass drain electrode 177g. The bypass source electrode 176g corresponds to the bypass drain region 177g doped with impurities in the bypass semiconductor layer 131g, and the bypass drain electrode 177g corresponds to the bypass drain region 177g doped with impurities in the bypass semiconductor layer 131g. The bypass source electrode 176g is directly connected to the light-emitting control drain region 133f.

[0160] The bypass semiconductor layer 131g is formed in the same layer as the driving semiconductor layer 131a, the switching semiconductor layer 131b, the light-emission control semiconductor layer 131f, etc., and a first gate insulating film 141 is formed on the bypass semiconductor layer 131g. A bypass gate electrode 125g, which is a part of the bypass control line 128, is formed on the first gate insulating film 141, and a second gate insulating film 142 is formed on the bypass gate electrode 125g and the first gate insulating film 141.

[0161] Therefore, the bypass thin film transistor T7 is always turned off by receiving the bypass signal BP from the bypass control line 128, and in the turned-off state, a part of the driving current Id flows through the bypass transistor T7 as the bypass current Ibp. Therefore, when a driving current for displaying a black image flows, an accurate black luminance image can be realized and the contrast ratio can be improved.

[0162] Although the present invention has been described with reference to the preferred embodiments as described above, it will be readily understood by those skilled in the art to which the present invention pertains that the present invention is not limited thereto and that various modifications and variations are possible without departing from the concept and scope of the appended claims. [Explanation of symbols]

[0163] 31:1st extension part 32:Second extension part 33: Bend 110: Substrate 121: Scan line 122: Previous scan line 123: Light emission control line 124: Initialization voltage line 125a: driving gate electrode 125b: switching gate electrode 131a: driving semiconductor layer 132b: switching semiconductor layer 141: First gate insulating film 142: Second gate insulating film 171: Data line 172: Drive voltage line

Claims

1. A substrate; a first scan line on the substrate and a data line crossing the first scan line; a switching thin film transistor connected to the first scan line and the data line; A driving voltage line; An initialization voltage line; an organic light-emitting diode; a driving thin film transistor electrically connected to the driving voltage line, the initialization voltage line, the organic light emitting diode, and the switching thin film transistor, the driving thin film transistor including a semiconductor layer; a compensation thin film transistor electrically connected to the driving voltage line and the driving thin film transistor; an insulating layer covering the driving thin film transistor; a storage capacitor including a first capacitor plate including a gate electrode of the driving thin film transistor, a second capacitor plate on the first capacitor plate, and a portion of the insulating layer between the first capacitor plate and the second capacitor plate; A connecting member; a first contact opening that exposes the first capacitor plate and is located within a storage opening formed in the second capacitor plate in a plan view; a second contact opening exposing a portion of the drain electrode of the compensation thin film transistor; Including, the connecting member is electrically connected to the compensation thin film transistor and the first capacitor plate through the first contact opening and the second contact opening; the driving thin film transistor includes a portion of the semiconductor layer; the storage capacitor overlaps a portion of the semiconductor layer; Organic light-emitting diode display.

2. 2. The organic light-emitting diode display device according to claim 1, wherein a portion of the semiconductor layer is curved under the gate electrode of the driving thin film transistor.

3. further comprising a protective layer; the organic light-emitting diode includes a pixel electrode on the protective layer; The organic light emitting diode display device of claim 2 , wherein the pixel electrode overlaps a portion of the semiconductor layer and the storage capacitor.

4. The organic light emitting diode display device according to claim 1 , further comprising an initialization thin film transistor electrically connected to the initialization voltage line and the compensation thin film transistor.

5. The organic light emitting diode display device according to claim 4 , further comprising a second scan line electrically connected to the initialization thin film transistor.

6. The organic light-emitting diode display device according to claim 2 , wherein the connecting members overlap the first scan lines in a plan view.

7. 3. The organic light emitting diode display device of claim 2, wherein the compensation thin film transistor comprises a dual gate.

8. 2. The organic light-emitting diode display device according to claim 1, wherein the semiconductor layer of the driving thin film transistor is curved and disposed in a plane substantially parallel to a surface of the substrate.

9. 2. The organic light emitting diode display device according to claim 1, wherein the switching thin film transistor utilizes the semiconductor layer.

10. The organic light-emitting diode display device according to claim 2 , wherein a portion of the semiconductor layer and a portion of the insulating layer overlap each other.

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