KR102412010B1 - Organic light emitting device - Google Patents

Abstract

The organic light emitting diode according to the present invention includes a first electrode and a second electrode, an organic light emitting diode including an organic layer positioned between the first electrode and the second electrode, a driving transistor for driving the organic light emitting diode, and sensing characteristics of the driving transistor and a bank layer including a sensing transistor, a first opening defining a light emitting region, and a second opening positioned to correspond to the sensing transistor.

Description

Organic light emitting device {ORGANIC LIGHT EMITTING DEVICE}

The present embodiments relate to an organic light emitting device.

In the flat panel display field, a light and low power consumption liquid crystal display device has been widely used so far, but the liquid crystal display device is a non-emissive device that cannot generate light by itself, and thus has luminance and contrast. ratio), a viewing angle, and a large area, etc. have disadvantages.

Accordingly, the development of a new flat panel display capable of overcoming the disadvantages of the liquid crystal display is being actively developed. One of the new flat panel display devices, an organic light emitting diode display, is a light emitting device that generates light by itself. Compared to the device, it has superior luminance, viewing angle and contrast ratio, and since it does not require a backlight, it can be lightweight and thin, and is advantageous in terms of power consumption.

The organic light emitting diode display displays an image using light emitted from an organic light emitting diode connected to a thin film transistor in each pixel area. The characteristic value of the thin film transistor is not uniform or is changed over time, so it is necessary to sense the characteristic value of the thin film transistor, transmit the correct value to the circuit unit, and compensate.

However, the organic light emitting display device senses the characteristic values of the thin film transistors for various reasons and fails to transmit the correct values to the circuit unit, so that defects such as luminance non-uniformity and unevenness occur.

An object of the present exemplary embodiments is to provide an organic light emitting diode that transmits accurate values of the characteristic values of the driving transistors DTR to a circuit unit to prevent defects such as luminance non-uniformity and unevenness in advance.

In order to solve the above-described problems, an organic light emitting diode according to an embodiment includes a first electrode and a second electrode, an organic light emitting diode including an organic layer positioned between the first electrode and the second electrode, and driving the organic light emitting diode. and a bank layer including a driving transistor, a sensing transistor sensing a characteristic value of the driving transistor, and a first opening defining an emission region and a second opening positioned to correspond to the sensing transistor.

In another aspect, the organic light emitting device in another embodiment defines a light emitting region by exposing a thin film transistor positioned on a substrate, an insulating film positioned on the thin film transistor, a first electrode positioned on the insulating film, and a portion of the first electrode and a bank layer including a first opening and a second opening positioned to correspond to a portion of the thin film transistor, an organic layer positioned on the first electrode, and a second electrode positioned on the organic layer.

The present embodiments have an effect of preventing defects such as luminance non-uniformity and unevenness in advance by transmitting accurate values of the characteristic values of the driving transistors DTR to the circuit unit.

1 is a system configuration diagram of an organic light emitting display device to which embodiments are applied.
2 is a circuit diagram of an organic light emitting diode according to an exemplary embodiment.
3 is a circuit diagram of an organic light emitting diode according to another exemplary embodiment.
FIG. 4 is a circuit diagram further including a light blocking layer in the organic light emitting diode of FIG. 3 .
5 is a cross-sectional view of an organic light emitting diode according to another exemplary embodiment.
FIG. 6 shows an optical path of light emitted from the organic layer of the organic light emitting diode of FIG. 5 .
7 is a cross-sectional view of another example of the organic light emitting device of FIG. 5 .
FIG. 8 is a cross-sectional view of another example of the organic light emitting diode of FIG. 5 .
9 to 12 are plan views illustrating the positional relationship of the semiconductor layer, the gate electrode, and the second opening of the thin film transistor included in the organic light emitting device of FIG. 5 .
13 and 14 are plan layout views of other examples of the light blocking layer shown in FIG. 8 in an organic light emitting diode display in which four sub-pixels constitute one pixel.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the embodiments of the present invention, if it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is formed between each component. It should be understood that elements may also be “connected,” “coupled,” or “connected.” In the same vein, when it is described that a component is formed "on" or "below" another component, the component is both formed directly on the other component or indirectly through another component. should be understood as including

1 is a system configuration diagram of an organic light emitting display device to which embodiments are applied.

Referring to FIG. 1 , the organic light emitting diode display 100 includes a timing controller 110 , a data driver 120 , a gate driver 130 , and an organic light emitting display panel 140 .

The timing controller 110 is configured to control the data driver 120 based on external timing signals such as vertical/horizontal synchronization signals Vsync and Hsync input from the host system, image data data, and a clock signal CLK. A data control signal (DCS) and a gate control signal (GCS) for controlling the gate driver 130 are output. In addition, the timing controller 110 converts image data input from the host system into a data signal format used by the data driver 120 , and supplies the converted image data 'data' to the data driver 120 . have.

In response to the data control signal DCS input from the timing controller 110 and the converted image data data', the data driver 120 converts the image data data' to the data signal (voltage value corresponding to the grayscale value) It is converted into an analog pixel signal or data voltage) and supplied to the data lines D1 to Dm.

The gate driver 130 sequentially supplies a scan signal (a gate pulse, a scan pulse, or a gate-on signal) to the gate lines G1 to Gn in response to the gate control signal GCS input from the timing controller 110 .

Meanwhile, on the organic light emitting display panel 140 , at least two or more pixels are formed in a pixel area (PA) defined by the data lines D1 to Dm and the gate lines G1 to Gn and arranged in a matrix form. It may include an organic light emitting device (Organic Light Emitting Device).

In each organic light emitting device P, gate lines G1 to Gn, data lines D1 to Dm, and driving voltage lines for supplying a driving voltage or a high potential voltage EVDD are disposed in each pixel area PA. have. In addition, each organic light emitting diode (P) includes an organic light emitting diode (OLED) including a first electrode, a second electrode, and an organic layer positioned between the first electrode and the second electrode, and the organic light emitting diode. It may include a driving transistor (DT) for supplying current and a sensing transistor (ST) for sensing a characteristic value of the driving transistor.

Hereinafter, with reference to the drawings, the circuit configuration of each organic light emitting device (P) will be described in more detail.

2 is a circuit diagram of an organic light emitting diode according to an exemplary embodiment.

Referring to FIG. 2 , in the organic light emitting diode display 100 according to the present exemplary embodiment, the organic light emitting diode 200 according to the exemplary embodiment includes an organic light emitting diode (OLED) and an organic light emitting diode. It includes a driving transistor (DTR) and a sensing transistor (STR) for driving the diode (OLED).

The organic light emitting diode (OLED) may include a first electrode (eg, an anode electrode), an organic layer, and a second electrode (eg, a cathode electrode). The organic light emitting diode OLED is positioned between the driving transistor DTR and the base voltage EVSS.

The driving transistor DRT drives the organic light emitting diode OLED by supplying a driving current to the organic light emitting diode OLED.

The first node N1 of the driving transistor DRT may be electrically connected to the first electrode of the organic light emitting diode OLED, and may be a source node or a drain node. The second node N2 of the driving transistor DRT may be electrically connected to a source node or a drain node of the switching transistor SWT, and may be a gate node. The third node N3 of the driving transistor DRT may be electrically connected to a driving voltage line (DVL) supplying the driving voltage EVDD, and may be a drain node or a source node.

On the other hand, in the case of the organic light emitting diode display 100 according to the present embodiments, as the driving time of the organic light emitting diode 200 increases, circuit elements such as the organic light emitting diode (OLED) and the driving transistor (DRT) are applied. Degradation may proceed. Accordingly, unique characteristic values (eg, threshold voltage, mobility, etc.) of circuit elements such as organic light emitting diodes (OLEDs) and driving transistors (DRTs) may change. A change in the characteristic value of such a circuit element causes a change in luminance of the corresponding organic light emitting diode (OLED).

The sensing transistor STR may sense unique characteristic values (eg, threshold voltage, mobility, etc.) of circuit elements such as an organic light emitting diode (OLED) and a driving transistor (DRT). In the sensing transistor STR, one of a source node or a drain node is connected to the first node N1 of the driving transistor DTR, and the other one of the source node or the drain node is connected to the sensing line RVL. It is connected to the node N4 , and a gate node is connected to the gate line GL in one way. In other words, the sensing transistor STR is positioned between one of the source node or the drain node of the driving transistor and the sensing line.

The organic light emitting diode 200 according to an embodiment includes a switching transistor (SWT) for transferring a data voltage to a second node N2 corresponding to a gate node of the driving transistor DRT, and an image signal voltage. It may include a storage capacitor (Cstg: Storage Capacitor) that maintains a data voltage corresponding to or a voltage corresponding thereto for one frame time.

The organic light emitting device 200 according to an embodiment includes a bank layer 210 defining a light emitting region. The bank layer 210 is positioned between the first electrode of the organic light emitting diode (OLED) and the organic layer, and exposes a portion of the first electrode to define a light emitting area (LEA) and sensing. and a second opening 214 positioned to correspond to the transistor STR.

The bank layer 210 may apply a black bank having a black-based color. For example, the bank layer 210 may be formed of at least one selected from organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel, but is not limited thereto. Since a black bank is applied to the bank layer 210 , a light leakage defect can be solved.

In the organic light emitting device 200 , the bank layer 210 exposes the first electrode through the first opening 212 in the light emitting region and covers all the remaining regions. The first electrode, the organic layer, and the second electrode are positioned in the light emitting region defined by the first opening 212 to emit light. Therefore, since there is no other insulating layer between the first electrode and the second electrode so that the organic light emitting diode (OLED) including the first electrode, the organic layer, and the second electrode can act as a diode, only the light emitting region of the first layer of the bank layer 210 It is sufficient to open only the opening 212 .

When a transparent bank is applied to the bank layer 210 without applying a black-based black bank, the upper portion of the sensing transistor STR is exposed to light to cancel the PBTS applied when sensing the characteristic value of the driving transistor DTR. However, when the aforementioned black bank is applied to the bank layer 210 to solve the light leakage failure, all light is blocked and the positive shift change of the sensing transistor STR becomes large, so that the characteristic value (eg, threshold) of the driving transistor DTR is increased. voltage, mobility) may not be able to transmit accurate values when sensing.

In other words, in the OLED external compensation structure that senses the characteristic value of the driving transistor through the sensing transistor STR and externally compensates the characteristic value by reflecting the sensed characteristic, the gate signal is sent to the sensing transistor STR to periodically sense the characteristic value of the driving transistor. The gate high voltage (eg, 24V) is applied for a long time to receive a strong PBTS. Since the black bank applied to the bank layer 210 blocks all light entering the upper part of the sensing transistor (STR), the effect of the NBTS that cancels it is reduced. Accordingly, the degree of positive shift of the threshold voltage of the sensing transistor STR becomes severe, and thus it may be impossible to accurately transmit the sensing value of the characteristic value of the driving transistor.

However, in the organic light emitting device 200 according to the embodiment, as described above, the bank layer 210 is positioned between the first electrode and the organic layer and light emitted from the organic layer positioned in the first opening 212 is transmitted through the second opening. The sensing transistor STR is reached through 214 . In other words, light emitted from the organic layer of the organic light emitting diode is reflected from the second electrode and reaches the sensing transistor STR through the second opening 214 . Light emitted from the corresponding organic light emitting device 200 may reach the sensing transistor STR, but light emitted from at least one adjacent organic light emitting device may also reach the corresponding sensing transistor STR. In this regard, it will be described later with reference to FIG. 6 .

The driving transistor DTR and the sensing transistor STR may be implemented as an n-type as shown in FIG. 2 or a p-type as shown in FIG. 3 .

3 is a circuit diagram of an organic light emitting diode according to another exemplary embodiment.

The organic light emitting diode 300 according to another embodiment includes an organic light emitting diode (OLED), a driving transistor (DTR) for driving the organic light emitting diode (OLED), and a sensing transistor (STR).

The first node N1 of the driving transistor DRT is connected to the base voltage EVSS. The second node N2 of the driving transistor DRT may be electrically connected to a source node or a drain node of the switching transistor SWT, and may be a gate node. The third node N3 of the driving transistor DRT may be connected to the organic light emitting diode OLED.

In the sensing transistor STR, one of a source node or a drain node is connected to the third node N3 of the driving transistor DTR, and the other of the source node or drain node is connected to the sensing line RVL. It is connected to the node N4 , and a gate node is connected to the gate line GL in one way.

In other words, in the organic light emitting diode 300 according to another embodiment, the organic light emitting diode OLED and the driving transistor DTR are connected in series between the driving voltage EVDD and the base voltage EVSS, and the organic light emitting diode OLED. A third node N3 between the and the driving transistor DTR may be connected to the sensing transistor STR.

The organic light emitting device 300 according to another embodiment is also located between the first electrode of the organic light emitting diode (OLED) and the organic layer, and a first opening 312 that exposes a part of the first electrode to define the light emitting area LEA ) and a bank layer 310 including a second opening 314 positioned to correspond to the sensing transistor STR.

In the organic light emitting devices 200 and 300 according to the above-described embodiments, the second openings 214 and 314 are disposed at positions corresponding to the sensing transistors STR, so that the upper portions of the sensing transistors STR are formed with the second openings 214 . , 314) to make the NBTS more intensely exposed to light. Accordingly, the degree of positive shift of the threshold voltage of the sensing transistor STR may be alleviated.

When the threshold voltage of the sensing transistor STR is positively shifted compared to the initial stage, the accurate value of the characteristic value (eg, threshold voltage, mobility) of the driving transistor DTR is transmitted to the timing controller 110 or the data driver through the sensing line SL. (120), etc., cannot be transmitted to the circuit part, so defects such as luminance non-uniformity and unevenness may appear. In the organic light emitting diode 300 according to another embodiment, since the second opening 314 is disposed in the bank layer 310, a positive shift of the sensing transistor STR is prevented, thereby preventing such defects such as luminance non-uniformity and unevenness in advance. can do.

FIG. 4 is a circuit diagram further including a light blocking layer in the organic light emitting diode of FIG. 3 .

The organic light emitting device 300 according to another embodiment corresponds to the driving transistor and the sensing transistor opposite to the driving transistor DTR and the sensing transistor STR on the opposite side with respect to the bank layer 310 as shown in FIG. 4 . A light blocking layer 320 may be additionally included at a position where As described above, since the light blocking layer 320 is disposed at a position corresponding to the sensing transistor STR, light entering from the outside is blocked from reaching the sensing transistor STR.

In order to periodically sense the characteristic value of the driving transistor, a gate high voltage (eg, 24V) is applied as a gate signal to the sensing transistor (STR) for a long time to receive stronger PBTS (Positive Bias Temperature Stress). The second openings 214 and 314 are disposed at corresponding positions to expose the upper portion of the sensing transistor STR to light through the second openings 214 and 314 to receive NBTS (Negative Bias Temperature Stress) more strongly. Accordingly, the degree of positive shift of the threshold voltage of the sensing transistor STR is alleviated, and a more accurate value of the characteristic value (eg, threshold voltage, mobility) of the driving transistor DTR is transmitted through the sensing line SL to the timing controller ( 110) or the data driver 120, etc., to prevent such defects in advance, such as non-uniformity in luminance and unevenness.

The organic light emitting diodes according to the embodiments have been described in terms of circuits with reference to FIGS. 2 to 4 above. Hereinafter, an organic light emitting diode according to embodiments will be described in terms of a cross-sectional structure with reference to FIGS. 5 to 9 .

5 is a cross-sectional view of an organic light emitting diode according to another exemplary embodiment.

Referring to FIG. 5 , an organic light emitting device 500 according to another exemplary embodiment includes a thin film transistor 520 positioned on a substrate 510 , an insulating film 530 positioned on the thin film transistor 520 , and an insulating film 530 . ) positioned on the first electrode 540 , the insulating film 530 and the bank layer 550 positioned on the first electrode 540 , the organic layer 560 positioned on the first electrode 540 and the organic layer ( A second electrode 570 positioned on the 560 is included.

The substrate 510 may be a plastic substrate including polyethylen terephthalate (PET), polyethylen naphthalate (PEN), polyimide, etc. as well as a glass substrate. In addition, a buffering layer for blocking penetration of impurity elements may be further provided on the substrate 510 . The buffer layer may be formed of, for example, a single layer or multiple layers of silicon nitride or silicon oxide.

The thin film transistor 520 may be formed of one of amorphous silicon, polysilicon, and metal oxide. The thin film transistor 520 is an example, and a metal oxide, for example, IGZO (Indium Gallium Zinc Oxide), IGO (Indium Gallium Oxide), IZO (Indium Zinc Oxide), IZO (Indium Zinc Oxide), ZTO (Zinc Tin Oxide) , may be an oxide transistor made of one of indium hafnium zinc oxide (IHZO) and in zirconium zinc oxide (IZZO).

In addition, the thin film transistor 520 includes a semiconductor layer 522 , a gate insulating film 523 formed on the semiconductor layer 522 , a gate electrode 524 formed on the gate insulating film 523 , and an interlayer formed on the gate electrode 524 . It may include a source electrode/drain electrode 526 formed on the insulating layer 525 and the interlayer insulating layer 525 and connected to the semiconductor layer 522 through a contact hole.

As shown in FIGS. 2 to 4 , the thin film transistor 520 is connected to one of a source node or a drain node of the driving transistor DTR supplying current to the organic layer 560 to sense the characteristic value of the driving transistor. It may be a sensing transistor STR, but is not limited thereto.

The organic light emitting device 500 may include an insulating layer 530 formed on the thin film transistor 520 . The insulating film 530 may be single or multi-layered. The insulating layer 530 may be a planarization layer or an overcoat layer.

The insulating layer 530 may be formed of an inorganic insulating material including any one of SiOx, SiNx, SiON, Al2O3, TiO2, Ta2O5, HfO2, ZrO2, BST, and PZT, benzocyclobutene (BCB), or an acryl-based resin. It may be an organic insulating material comprising a, or a combination thereof.

The first electrode 540 may be an anode electrode (anode), a work function value of a relatively large, transparent conductive material, for example, a metal oxide such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), ZnO Mixtures of oxides with metals such as :Al or SnO2:Sb, poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene](PEDT), polypyrrole and polyaniline It may be made of the same conductive polymer or the like. In addition, the pixel electrode 272 may be a carbon nano tube (CNT), graphene, silver nano wire, or the like.

Meanwhile, the bank layer 550 has a matrix-like lattice structure on the entire substrate 510 , surrounds the edge of the first electrode 540 , and exposes a portion of the first electrode 540 .

The bank layer 550 may apply a black bank. The bank layer 550 may be formed of at least one selected from organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel, but is not limited thereto.

The bank layer 550 has a first opening 552 that exposes a portion of the first electrode 540 to define a light emitting region and a second opening that corresponds to a portion of the semiconductor layer 522 of the thin film transistor 520 . (554).

In consideration of the step coverage of the organic layer 560 and the second electrode 570 positioned on the bank layer 550 , the first opening 552 is bent at a predetermined angle from the bottom surface 552a in contact with the insulating layer 530 . has been In other words, the first opening 552 is opened in an inverted tapered shape in which the area of the top surface 552b is larger than that of the bottom surface 552a in contact with the insulating film 530 . Similarly, the second opening 554 is also opened in a reverse tapered shape in which the area of the top surface 554b is larger than that of the bottom surface 554a in contact with the insulating film 530 . In terms of processing, for example, the first opening 552 and the second opening 554 are simultaneously formed through a photolithography process with a mask in a state in which the material of the bank layer 550 is applied. The side inclination of the two openings 554 may be the same, but is not limited thereto.

The organic layer 560 may include a hole injection layer, a hole transport layer, a light emitting layer, a light emission auxiliary layer, an electron transport layer, an electron injection layer, and the like. The organic layer 560 of FIG. 5 is applied over the entire surface without patterning. By omitting the patterning process, there is an effect of bringing simplicity in the process.

A second electrode 570 is disposed on the organic layer 560 . The second electrode 570 may be a cathode electrode (cathode), and may be made of a material having a relatively small work function value. For example, in the case of a bottom light emitting method, the second electrode 570 may be a metal, and a single layer of an alloy comprising a first metal, for example, Ag, and the like, and a second metal, for example, Mg, etc. in a certain ratio or a single layer thereof. It may be multiple layers.

FIG. 6 shows an optical path of light emitted from the organic layer of the organic light emitting diode of FIG. 5 .

In the organic light emitting device 500 according to another embodiment, the bank layer 550 is positioned between the first electrode 540 and the organic layer 560 and light emitted from the organic layer 560 positioned in the first opening 552 . The thin film transistor 520 is reached through the second opening 554 . In other words, light emitted from the organic layer 560 is reflected from the second electrode 570 and reaches the thin film transistor 520 through the second opening 554 . Light emitted from the corresponding organic light emitting device 500 may reach the thin film transistor 520 , but light emitted from at least one adjacent organic light emitting device may also reach the corresponding thin film transistor 520 .

Accordingly, the degree of positive shift of the threshold voltage of the thin film transistor 520 is alleviated, and when the thin film transistor 520 is a sensing transistor STR that senses the characteristic values of the driving transistors DTR shown in FIGS. 2 to 4 . , the thin film transistor 520 transmits a more accurate value of the characteristic value (eg, threshold voltage, mobility) of the driving transistor DTR to a circuit unit such as the timing controller 110 or the data driver 120 through the sensing line SL. Thus, it is possible to prevent such defects such as non-uniformity of brightness and stains in advance.

The organic light emitting device 500 illustrated in FIG. 5 may be a white organic light emitting device in which the organic layer 560 emits white light. To this end, in the organic light emitting device 500 , the organic layer 560 and the second electrode 570 may be disposed on the entire surface of the substrate 510 . The organic layer 560 of the organic light emitting device 500 has a process advantage that can be applied to the entire surface in one process. The organic light emitting diode 500 may include a color filter layer 580 above or below the first electrode 540 at a position corresponding to the first opening 552 of the bank layer 550 .

The color filter layer 580 of the organic light emitting device 500 may have any one of red, blue, and green colors. In addition, in the case of the organic light emitting device 500 in which white is realized, the color filter layer 580 may not be formed. Red, blue, and green arrays may be formed in various ways, and a black matrix (not shown) made of a material capable of absorbing external light may be provided between each color filter layer 580 .

7 is a cross-sectional view of another example of the organic light emitting device of FIG. 5 .

When the organic light emitting device 500 is a bottom light emitting type, the color filter layer 580 may be positioned under the first electrode 540 as shown in FIG. 7 . The light generated in the organic layer 560 is reflected from the second electrode 570 and exits to the outside of the organic light emitting device 500 through the color filter layer 580 .

Although the organic light emitting device 500 is illustrated as a bottom emission type in which the emission direction is from the first electrode 540 to the substrate 510 direction, the present invention is not limited thereto and a top emission type. can depend on In the case of the upper emission organic light emitting device 500 , the color filter layer 580 may be located on the first electrode 540 .

FIG. 8 is a cross-sectional view of another example of the organic light emitting diode of FIG. 5 .

As shown in FIG. 8 , in the organic light emitting device 500 , a light blocking layer 590 formed to correspond to the thin film transistor 520 may be formed between the substrate 510 and the thin film transistor 520 . A buffer layer 592 may be disposed between the substrate 510 and the light blocking layer 590 .

The light blocking layer 590 protects the semiconductor layer 522 from external light, and prevents external light from being reflected to reduce visibility, improve luminance, and reduce contrast characteristics. Here, external light introduced through the substrate 510 may be non-polarized light.

As described above, in the thin film transistor 520 of the organic light emitting device 500 according to another embodiment, the semiconductor layer 522 may be an oxide transistor made of a metal oxide, and the semiconductor of the thin film transistor 520 . A light blocking layer 590 may be formed in a region corresponding to the layer 522 . This is because, in the case of an oxide transistor, when external light is introduced into the semiconductor layer 522 , electrical properties or chemical properties may change.

Meanwhile, the light blocking layer 590 may have a multilayer structure. Specifically, the light blocking layer 590 may include a conductive layer and one or more low reflection layers. The conductive layer is made of, for example, any one of Al, Pt, Pd, Ag, Mg, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W, Cu, or an alloy thereof. can, but is not limited thereto. The one or more low-reflection layers may be made of a material that absorbs external light introduced through the substrate 510 , or a light absorber may be applied thereto.

9 to 12 are plan views illustrating the positional relationship of the semiconductor layer, the gate electrode, and the second opening of the thin film transistor included in the organic light emitting device of FIG. 5 .

5 and 9 , the thin film transistor 520 included in the organic light emitting diode 500 according to another embodiment includes a semiconductor layer 522 and a gate electrode 524 crossing the semiconductor layer 522 . include

The gate electrode 524 may be integrally formed with the gate line GL as described with reference to FIG. 2 . That is, a region where the gate line GL intersects and intersects the semiconductor layer 522 may serve as the gate electrode 524 . The gate electrode 524 may be patterned separately from the gate line GL to cross the semiconductor layer 522 .

As described above, the second opening 554 is opened in a reverse tapered shape in which the area of the top surface 554b is larger than that of the bottom surface 554a. That is, the side surface of the second opening 554 is inclined at a predetermined angle. The planar shape of the second opening 554 may be a square shape as shown in FIG. 9 , but is not limited thereto. For example, the planar shape of the second opening 554 may be a circular shape as shown in FIG. 10 or other shapes.

The bottom surface 554a of the second opening 554 may surround an intersection region where the semiconductor layer 552 of the thin film transistor 520 and the gate electrode 554 intersect, but is not limited thereto. For example, the bottom surface 554a of the second opening 554 may surround only a portion of an intersection region where the semiconductor layer 552 of the thin film transistor 520 and the gate electrode 554 intersect.

When the bottom surface 554a of the second opening 554 surrounds the intersection region where the semiconductor layer 552 of the thin film transistor 520 and the gate electrode 554 intersect, the semiconductor layer 552 of the thin film transistor 520 is ) and the intersecting area of the gate electrode 554 and the bottom surface 554a of the second opening 554 may have substantially the same spacing.

For example, as shown in FIG. 9 , when the bottom surface 554a of the second opening 554 has a rectangular shape, the bottom surface 554a of the second opening 554 and the semiconductor layer 552 of the transistor 520 are Spaces L1 to L4 of the four sides of the intersection region where the gate electrode 554 and the gate electrode 554 intersect may be substantially the same. Also, as shown in FIG. 10 , when the bottom surface 554a of the second opening 554 has a circular shape, the bottom surface 554a of the second opening 554 is connected to the semiconductor layer 552 of the transistor 520 and the gate. The electrodes 554 may contact the four corners of the intersecting area.

As another example, the bottom surface 554a of the second opening 554 may surround four corners of the intersection region where the semiconductor layer 552 of the transistor 520 and the gate electrode 554 intersect, or may intersect the four sides. have.

When the bottom surface 554a of the second opening 554 has a rectangular shape, an intersection region where the bottom surface 554a of the second opening 554 crosses the semiconductor layer 552 of the transistor 520 and the gate electrode 554 Intervals L1 to L4 of the four sides of may be different from each other. For example, the gaps L1 between the two opposite sides of the cross region where the bottom surface 554a of the second opening 554 and the semiconductor layer 552 of the transistor 520 and the gate electrode 554 intersect. , L2) may be different from each other as shown in FIG. 11 (L2>L1), or spacings L3 and L3 of two other sides may also be different from each other as shown in FIG. 12 (L2>L1, L3). >L4).

For example, the bottom surface 554a of the second opening 554 may have a large opening in the direction of the first opening 552 based on the intersection region where the semiconductor layer 522 and the gate electrode 524 intersect. . In other words, the interval between the bottom surface 554a of the second opening 554 in the direction toward the first opening 552 and the intersection region where the semiconductor layer 552 of the transistor 520 and the gate electrode 554 intersect Since the arrangement is relatively long, more light emitted from the organic layer 560 located in the first opening 552 may reach the thin film transistor 520 through the second opening 554 .

Meanwhile, the light blocking layer 590 shown in FIG. 8 positioned between the thin film transistor 520 and the substrate 510 may be positioned to correspond to an intersection region where the semiconductor layer 522 and the gate electrode 524 intersect. . In this case, the area of the light blocking layer 590 is wider than the intersection area where the semiconductor layer 522 and the gate electrode 524 intersect, so that the light blocking layer 590 can surround all of the intersection area.

13 and 14 are plan layout views of other examples of the light blocking layer shown in FIG. 8 in an organic light emitting diode display in which four sub-pixels constitute one pixel.

Referring to FIG. 13 , the light blocking layer 590 includes two first and second patterns 591 and 592 that transmit a driving voltage EVDD to adjacent sub-pixels on a substrate 510 and a sensing line for adjacent sub-pixels. One third pattern 593 connected to the pixels and a fourth pattern 594 used as a plate of the storage capacitor of each sub-pixel may be included.

When the thin film transistor 520 is a sensing transistor in the planar arrangement of the light blocking layer 590 shown in FIG. 13 , the thin film transistor 520 has a space 595 between the third pattern 593 and the fourth pattern 594 . will be located in

Referring to FIG. 14 , the fourth pattern 594 included in the light blocking layer 590 is also patterned in the aforementioned space 595 to block the light of the thin film transistor 520 .

As described above, since the light blocking layer 320 is disposed at a position corresponding to the thin film transistor 520 , light entering from the outside is blocked from reaching the thin film transistor 520 . A second opening 554) is disposed at a position corresponding to the thin film transistor 520 to expose the upper portion of the thin film transistor 520 to light through the second opening 554 to receive the NBTS more strongly.

According to the above-described embodiments, the upper portion of the thin film transistor is exposed to light emitted from the organic light emitting device through an opening separately disposed in the bank layer, thereby alleviating the degree of positive shift in the threshold voltage of the thin film transistor, and the driving transistor ( DTR) characteristic values (eg, threshold voltage, mobility) are transmitted to the circuit part, which has the effect of preventing such defects such as luminance non-uniformity and unevenness in advance.

The embodiments have been described above with reference to the drawings, but the present invention is not limited thereto.

Terms such as "include", "comprise" or "have" described above mean that the corresponding component may be embedded, unless otherwise stated, and does not exclude other components. It should be construed as being able to further include other components. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

200: organic light emitting device
210: bank layer
212: first opening
214: second opening
OLED: organic light emitting diode
DTR: drive transistor
STR: Sensing Transistor

Claims (13)

an organic light emitting diode including a first electrode and a second electrode, and an organic layer positioned between the first electrode and the second electrode;
a driving transistor for driving the organic light emitting diode;
a sensing transistor for sensing a characteristic value of the driving transistor; and
An organic light emitting device comprising a bank layer including a first opening defining a light emitting region and a second opening positioned to correspond to the sensing transistor. The method of claim 1,
The bank layer is a black bank organic light emitting device. The method of claim 1,
The bank layer is an organic light emitting device comprising at least one selected from an organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel. The method of claim 1,
The sensing transistor is an organic light emitting diode positioned between one of a source node or a drain node of the driving transistor and a sensing line. The method of claim 1,
An organic light emitting device further comprising a light blocking layer at a position corresponding to the driving transistor and the sensing transistor opposite the driving transistor and the sensing transistor with respect to the bank layer. a thin film transistor positioned on a substrate;
an insulating film positioned on the thin film transistor;
a first electrode positioned on the insulating layer;
a bank layer including a first opening exposing a portion of the first electrode to define a light emitting region and a second opening positioned to correspond to the thin film transistor;
an organic layer positioned on the first electrode; and
a second electrode positioned on the organic layer;
The thin film transistor is a sensing transistor connected to one of a source node or a drain node of a driving transistor for supplying current to the organic layer to sense a characteristic value of the driving transistor. 7. The method of claim 6,
The bank layer is a black bank organic light emitting device. 7. The method of claim 6,
The bank layer is an organic light emitting device comprising at least one selected from an organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel. 7. The method of claim 6,
The organic layer and the second electrode are disposed on the entire surface of the substrate,
and a color filter layer above or below the first electrode at a position corresponding to the first opening of the bank layer. delete 7. The method of claim 6,
The second opening is opened in an inverted tapered shape having a top surface larger than a bottom surface in contact with the insulating film,
An organic light emitting device in which a bottom surface of the second opening surrounds an intersection region where the semiconductor layer of the thin film transistor and the gate electrode intersect. 12. The method of claim 11,
The bottom surface of the second opening is an organic light emitting device having a large area opened in the direction of the first opening based on an intersection region where the semiconductor layer and the gate electrode intersect. 7. The method of claim 6,
Further comprising a light blocking layer positioned between the thin film transistor and the substrate,
The light blocking layer is an organic light emitting device positioned to correspond to an intersection region where the semiconductor layer and the gate electrode of the thin film transistor intersect.

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