KR102464904B1 - Organic light emitting device display - Google Patents

Abstract

An organic light emitting display device according to the present invention includes at least one pixel composed of two or more sub-pixels, and at least one sub-pixel of the sub-pixels includes an organic light emitting diode, two or more transistors, and a first pixel defining a light emitting region. It includes one opening and a second opening positioned to correspond to at least one of the two or more transistors, and includes a bank layer to which a black bank is applied.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DEVICE DISPLAY}

The present embodiments relate to an organic light emitting display 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.

Development of a new flat panel display device capable of overcoming the disadvantages of the liquid crystal display device is being actively developed. An organic light emitting display device, which is one of the new flat panel display devices, is a light emitting device that generates light by itself. It has excellent 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.

An organic light emitting display device displays an image using light emitted from an organic light emitting diode connected to a thin film transistor in each pixel area. In the organic light emitting display device, the threshold voltage of the thin film transistor is shifted to positive or negative for various reasons, so that defects such as luminance non-uniformity and unevenness occur.

It is an object of the present embodiments to provide an organic light emitting display device that prevents defects such as luminance non-uniformity and unevenness in advance because the thin film transistor operates precisely because the threshold voltage of the thin film transistor is not shifted to positive or negative.

In order to solve the above problem, an organic light emitting display device according to an exemplary embodiment includes at least one pixel including two or more sub-pixels positioned in regions where two or more data lines and two or more gate lines intersect each other. include

At least one sub-pixel of the sub-pixels is an organic light-emitting diode including a first electrode and a second electrode, an organic layer positioned between the first electrode and the second electrode, applying a current to the organic light-emitting diode, or a characteristic value of another transistor. two or more transistors sensing and a bank layer to which a black bank is applied.

In this case, the bank layer may include a first opening defining a light emitting region and a second opening positioned corresponding to at least one of the two or more transistors.

In another aspect, in the organic light emitting display device according to another embodiment, two or more subpixels constituting one pixel are sequentially positioned on a thin film transistor positioned on a substrate, an insulating film positioned on the thin film transistor, and an insulating film positioned on the insulating film and an organic light emitting diode including a first electrode, an organic layer, and a second electrode, and a bank layer positioned on the insulating layer and the first electrode to define a light emitting region.

Meanwhile, in an organic light emitting display device according to another exemplary embodiment, a light blocking layer is disposed to correspond to the thin film transistor of at least one first subpixel among the subpixels, but is not disposed to correspond to the thin film transistor of at least one second subpixel of the subpixels. may include

In another aspect, an organic light emitting display panel according to another embodiment includes two or more data lines and two or more gate lines disposed in a direction crossing each other, and two or more data lines and two or more gate lines disposed in regions where the data lines and the gate lines intersect each other. It may include a pixel composed of sub-pixels.

In this case, at least one of the sub-pixels may include the aforementioned organic light emitting diode, two or more transistors, and a bank layer to which a black bank is applied.

In this case, the bank layer may include a second opening positioned to correspond to at least one of the two or more transistors together with the above-described first opening.

In the present embodiments, since the thin film transistor operates precisely because the threshold voltage of the thin film transistor is not shifted to positive or negative in the organic light emitting display device, defects such as luminance non-uniformity and unevenness can be prevented in advance.

1 is a system configuration diagram of an organic light emitting display device to which embodiments are applied.
2 illustrates an example in which four sub-pixels constitute one pixel.
3 is a plan view of a pixel according to an exemplary embodiment.
4 is a plan view of one pixel according to a comparative example.
5 shows a negative shift of the threshold voltage of the transistor.
6 shows a positive shift of the threshold voltage of the transistor.
7 is a cross-sectional view of the organic light emitting diode and the driving transistor of FIG. 3 .
FIG. 8 shows an optical path of light emitted from an organic layer of each subpixel of FIG. 7 .
9 is a cross-sectional view of another example of each subpixel of FIG. 3 .
FIG. 10 is a cross-sectional view of another example of each subpixel of FIG. 3 .
11 is a plan view of a pixel according to another exemplary embodiment.
12 is a plan view of a sub-pixel when the sub-pixel of FIG. 11 represents white.
13 to 16 are cross-sectional views of four sub-pixels constituting one pixel according to another exemplary embodiment.

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.

Also, 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 between each component. It should be understood that elements may 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 or indirectly through another component on the other 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 (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 a data signal (a voltage value corresponding to a 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, two or more sub-pixels arranged in a matrix form in each pixel area (PA) defined by the data lines D1 to Dm and the gate lines G1 to Gn on the organic light emitting display panel 140 . It may include (Sub Pixels).

Circuit elements such as transistors and capacitors are formed in each sub-pixel SP disposed in the organic light emitting display panel 110 schematically illustrated in FIG. 1 . For example, a circuit including an organic light emitting diode (OLED), two or more transistors, and one or more capacitors is formed in each sub-pixel on the organic light emitting display panel 110 .

At least two sub-pixels may constitute one pixel to express a color. Hereinafter, it will be described that four sub-pixels constitute one pixel, but the present invention is not limited thereto.

first embodiment

2 illustrates an example in which four sub-pixels constitute one pixel.

Referring to FIG. 2 , in the organic light emitting display panel 140 according to the present exemplary embodiments, four sub-pixels, for example, red (R), white (W), blue (B), and green (G) sub-pixels. Pixels may constitute one pixel (P:Pixel).

Each of the red (R), white (W), blue (B), and green (G) sub-pixels is an organic light-emitting diode (OLED) and a driving circuit for driving the organic light-emitting diode (OLED). It consists of a driving circuit (DC).

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 driving circuit DC may basically include a driving transistor (DTR), a switching transistor (SWT) and a sensing transistor (STR).

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

The switching transistor SWT is a transistor for transferring the data voltage Vdata to the N2 node corresponding to the gate node of the driving transistor DTR.

On the other hand, in the case of the organic light emitting display panel 140 according to the present embodiments, as the driving time of each of the red (R), white (W), blue (B), and green (G) subpixels increases, the organic Degradation of circuit elements such as a light emitting diode (OLED) and a driving transistor (DTR) may proceed. Accordingly, unique characteristic values (eg, threshold voltage, mobility, etc.) of circuit elements such as an organic light emitting diode (OLED) and a driving transistor (DTR) 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 the organic light emitting diode (OLED) and the driving transistor (DTR).

Each of the red (R), white (W), blue (B), and green (G) sub-pixels is a storage capacitor Cstg that maintains a data voltage corresponding to an image signal voltage or a voltage corresponding thereto for one frame time: Storage Capacitor) may be included.

3 is a plan view of a pixel according to an exemplary embodiment.

Referring to FIG. 3 , one pixel P may include red (R), white (W), blue (B), and green (G) sub-pixels. Each subpixel 200 is composed of an organic light-emitting diode (OLED) and a driving circuit (DC) for driving the organic light-emitting diode (OLED) as shown in FIG. 2 . .

Each subpixel 200 according to an exemplary embodiment includes a bank layer 210 defining a light emitting area. The bank layer 210 is positioned between the first electrode and the organic layer of the organic light emitting diode (OLED) and includes a first opening 212 and a driving circuit that exposes a part of the first electrode to define a light emitting area (LEA). and a second opening 214 positioned to correspond to a portion of the furnace. The second opening 214 may be positioned to correspond to at least one of the two or more transistors included in the driving circuit DC. 3 shows that the second opening 214 is positioned to correspond to the driving transistor DTR and the sensing transistor STR in the driving circuit, but is not limited thereto.

The bank layer 210 may apply a black bank including 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 present specification, a black bank refers to a bank having a color of a black series. Accordingly, the bank layer 210 may include a color other than the black-based color.

In each sub-pixel 200 , the bank layer 210 exposes the first electrode through the first opening 212 in the light emitting area and covers the remaining area. 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 film 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 Opening only the opening 212 may be sufficient.

4 is a plan view of one pixel according to a comparative example.

One pixel P according to the comparative example may include red (R), white (W), blue (B), and green (G) sub-pixels.

Each subpixel 300 includes a bank layer 310 defining a light emitting area. In each subpixel 300 , the bank layer 310 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). One opening 312 is included. In other words, the bank layer 310 to which the black bank is applied is disposed in the entire region of each subpixel 300 except for the first opening 312 .

When a black bank is applied to the bank layer 310 of each sub-pixel 300, both internal and external light are blocked and the threshold voltage Vth of the driving transistor DTR shown in FIG. 5 is negatively shifted by light. NBTS (Negative Bias Temperature Shift) characteristics are improved. On the other hand, when the black bank is applied to the driving circuit, light flowing into the transistors included in the driving circuit, for example, the driving transistor DTR is blocked and absorbed, so that the threshold voltage ( Vth) has a strong positive shift tendency, so that the current driving ability of the driving transistor DTR is deteriorated.

However, in each subpixel 200 according to an exemplary 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 driving transistor DTR 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 driving transistor DTR through the second opening 214 . Light emitted from the corresponding organic light emitting device 200 may reach the driving transistor DTR, but light emitted from at least one adjacent organic light emitting device may also reach the corresponding driving transistor DTR. Light is introduced into the driving transistor DTR to alleviate the positive shift tendency of the threshold voltage Vth of the driving transistor DTR, so that the current driving ability of the driving transistor DTR may be maintained.

When the bank layer 210 applies a transparent bank instead of applying a black-based black bank, the upper portion of the sensing transistor STR is exposed to light to sense the characteristic value of the driving transistor DTR (Positive Bias Temperature Shift (PBTS)) ) is offset. 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 an 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 value, the sensing transistor STR is gated with a gate signal to periodically sense the characteristic value of the driving transistor. A 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. The degree of positive shift of the threshold voltage of the sensing transistor STR may become severe, so that it may not be possible to accurately transmit the sensing value of the characteristic value of the driving transistor.

However, in each subpixel 200 according to an exemplary 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 each subpixel 200 according to the above-described embodiments, a second opening 214 is disposed at a position corresponding to the sensing transistor STR, so that the upper portion of the sensing transistor STR is illuminated through the second opening 214 . Exposure to NBTS to make it stronger. 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. Since it cannot be transmitted to the circuit unit such as (120), defects such as luminance non-uniformity and unevenness may appear. In each subpixel 200 according to another embodiment, since the second opening 214 is disposed in the bank layer 210 , the optical path of the light flowing into the transistor is secured and the sensing transistor STR is activated through the activation of photoinduced electrons. By preventing positive shift, it is possible to prevent such defects such as uneven luminance and unevenness in advance.

As described above, although FIG. 3 illustrates that the second opening 214 is positioned to correspond to the driving transistor DTR and the sensing transistor STR in the driving circuit, the present invention is not limited thereto. For example, when a black bank is applied to the driving circuit, light flowing into the switching transistor SWT is blocked and absorbed, and the threshold voltage Vth of the switching transistor SWT has a strong positive shift tendency, so that the data of the switching transistor SWT is The ability to switch voltages is reduced. Accordingly, the second opening 214 may be positioned to correspond to the switching transistor SWT.

Hereinafter, each sub-pixel according to the embodiments will be described in terms of a cross-sectional structure with reference to FIGS. 7 to 10 . In this case, the cross-sectional structure of the driving transistor will be described as an example, but the cross-sectional structure of other transistors may also be applied in the same or similar manner.

7 is a cross-sectional view of the organic light emitting diode and the driving transistor of FIG. 3 .

Referring to FIG. 7 , each subpixel 200 is positioned on a driving transistor 420 positioned on a substrate 410 , an insulating layer 430 positioned on the driving transistors 420 and DTR, and an insulating layer 430 . on the first electrode 440 , the insulating layer 430 and the bank layer 210 positioned on the first electrode 440 , the organic layer 460 and the organic layer 460 positioned on the first electrode 440 . and a second electrode 470 positioned thereon.

The substrate 410 may be not only a glass substrate, but also a plastic substrate including polyethylen terephthalate (PET), polyethylen naphthalate (PEN), polyimide, or the like. In addition, a buffering layer for blocking the penetration of impurity elements may be further provided on the substrate 410 . The buffer layer may be formed of, for example, a single layer or multiple layers of silicon nitride or silicon oxide.

The driving transistor 420 may be formed of one of amorphous silicon, polysilicon, and metal oxide. The driving transistor 420 is an example of a metal oxide, for example, indium gallium zinc oxide (IGZO), indium gallium oxide (IGO), indium zinc oxide (IZO), indium zinc oxide (IZO), or zinc tin oxide (ZTO). , may be an oxide transistor made of one of indium hafnium zinc oxide (IHZO) and in zirconium zinc oxide (IZZO).

The driving transistor 420 is a driving transistor DTR that supplies a current to the organic layer 460 . The driving transistor 420 includes a semiconductor layer 422 , a gate insulating film 423 formed on the semiconductor layer 422 , a gate electrode 424 formed on the gate insulating film 423 , and an interlayer insulating film formed on the gate electrode 424 . It may include a source electrode/drain electrode 426 formed on the 425 and the interlayer insulating layer 425 and connected to the semiconductor layer 422 through a contact hole.

Each subpixel 200 may include an insulating layer 430 formed on the driving transistor 420 . The insulating film 430 may be single or multi-layered. The insulating layer 430 may be a planarization layer or an overcoat layer.

The insulating layer 430 is an inorganic insulating material including any one of SiO _x , SiN _x , SiON, Al ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , HfO ₂ , ZrO ₂ , BST and PZT, benzocyclobutene (BCB). ) or an organic insulating material including an acryl-based resin, or a combination thereof.

The first electrode 440 may be an anode electrode (anode), a work function value is relatively large, a transparent conductive material, for example, a metal oxide such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), ZnO :Al or SnO ₂ : Mixtures of metals and oxides such as Sb, poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene](PEDT), polypyrrole and polyaniline It may be made of a conductive polymer such as In addition, the first electrode 440 may be a carbon nano tube (CNT), graphene, silver nano wire, or the like.

Meanwhile, the bank layer 210 has a matrix-like lattice structure on the entire substrate 410 , surrounds the edge of the first electrode 440 , and exposes a portion of the first electrode 440 .

The bank layer 210 may apply a black bank. 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.

The bank layer 210 has a first opening 212 that exposes a portion of the first electrode 440 to define a light emitting region and a second opening that corresponds to a portion of the semiconductor layer 422 of the thin film transistor 420 . (214).

In consideration of the step coverage of the organic layer 460 and the second electrode 470 positioned on the bank layer 210 , the first opening 212 is bent at a predetermined angle from the bottom surface 212a in contact with the insulating layer 430 . has been In other words, the first opening 212 is opened in a reverse tapered shape in which the area of the top surface 212b is larger than that of the bottom surface 212a in contact with the insulating layer 430 .

Similarly, the second opening 214 is also opened in a reverse tapered shape in which the area of the top surface 214b is larger than that of the bottom surface 214a in contact with the insulating film 430 . In terms of the process, for example, the first opening 212 and the second opening 214 are simultaneously formed through a photolithography process using a mask in a state in which the material of the bank layer 210 is applied. The side inclination of the two openings 214 may be the same, but is not limited thereto.

The planar shape of the second opening 214 may be a rectangular shape as shown in FIG. 3 , but is not limited thereto. For example, the second opening 214 may have another shape, such as a circular shape.

The organic layer 460 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 460 of FIG. 7 may be applied to the entire surface without patterning. Since the organic layer 460 is applied to the entire surface, the patterning process is omitted, which has the effect of bringing convenience in the process.

A second electrode 470 is disposed on the organic layer 460 . The second electrode 470 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 the bottom light emitting method, the second electrode 470 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. 8 shows an optical path of light emitted from an organic layer of each subpixel of FIG. 7 .

In each sub-pixel 200 , the bank layer 210 is positioned between the first electrode 440 and the organic layer 460 and light emitted from the organic layer 460 positioned in the first opening 212 is transmitted through the second opening ( The driving transistor 420 is reached through 214 . In other words, light emitted from the organic layer 460 is reflected from the second electrode 470 and reaches the driving transistor 420 through the second opening 214 . Light emitted from each sub-pixel 200 may reach the driving transistor 420 , but light emitted from at least one adjacent sub-pixel may also reach the driving transistor 420 .

9 is a cross-sectional view of another example of each subpixel of FIG. 3 .

In each subpixel 200 , the organic layer 460 may be an organic layer emitting white light. To this end, the organic layer 460 of each subpixel 200 and the second electrode 470 may be disposed on the entire surface of the substrate 410 . The organic layer 460 of each sub-pixel 200 has a process advantage that it can be applied to the entire surface in one process. As shown in FIG. 9 , each subpixel 200 may include a color filter layer 480 above or below the first electrode 440 at a position corresponding to the first opening 212 of the bank layer 210 . can

The color filter layer 480 of each sub-pixel 200 may have any one of red, blue, and green colors. In addition, in the case of each sub-pixel 200 in which white is implemented, the color filter layer 480 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 480 .

When each subpixel 200 is a bottom emission type, the color filter layer 480 may be located under the first electrode 440 as shown in FIG. 9 . The light generated in the organic layer 460 is reflected from the second electrode 470 and exits to the outside of the organic light emitting device 200 through the color filter layer 480 .

Each subpixel 200 is shown as a bottom emission type in which the emission direction is from the first electrode 440 to the substrate 410 direction, but the present invention is not limited thereto. can depend on In the case of the upper emission organic light emitting diode 200 , the color filter layer 480 may be located on the second electrode 470 .

FIG. 10 is a cross-sectional view of another example of each subpixel of FIG. 3 .

10 , in each subpixel 200 , a light blocking layer 490 formed to correspond to the driving transistor 420 may be formed between the substrate 410 and the driving transistor 420 . A buffer layer 492 may be disposed between the substrate 410 and the light blocking layer 490 .

The light blocking layer 490 protects the semiconductor layer 422 from external light, and functions to prevent external light from being reflected to reduce visibility, improve luminance, and reduce contrast characteristics. Here, the external light introduced through the substrate 410 may be non-polarized light.

As described above, the driving transistor 420 of each subpixel 200 according to another embodiment may be an oxide transistor in which the semiconductor layer 422 is made of a metal oxide, and a semiconductor of the driving transistor 420 . A light blocking layer 490 may be formed in a region corresponding to the layer 422 . This is because, in the case of the oxide transistor, when external light is introduced into the semiconductor layer 422 , electrical properties or chemical properties may change.

Meanwhile, the light blocking layer 490 may have a multilayer structure. Specifically, the light blocking layer 490 may include a conductive layer and one or more low reflection layers. The conductive layer may be 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 410 , or a light absorber may be applied thereto.

In the above-described embodiments, it has been described that the bank layer 210 includes the second opening 214 in all sub-pixels constituting one pixel, but only the bank layer 210 in at least one sub-pixel among the sub-pixels. ) may include only the second opening 214 .

second embodiment

11 is a plan view of a pixel according to another exemplary embodiment.

Referring to FIG. 11 , one pixel P may include red (R), white (W), blue (B), and green (G) sub-pixels. As shown in FIG. 2, each sub-pixel 500A and 500B includes an organic light-emitting diode (OLED) and a driving circuit (DC) for driving the organic light-emitting diode (OLED). is composed

Each of the sub-pixels 500A and 500B according to an exemplary embodiment includes a bank layer 510 defining an emission region. In order to solve the light leakage defect as described above, the bank layer 510 is made of at least one selected from organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel. can be applied.

The bank layer 510 is positioned between the first electrode and the organic layer of the organic light emitting diode (OLED) and includes a first opening 512 that exposes a portion of the first electrode to define a light emitting area (LEA). do. At least one sub-pixel 500A among the sub-pixels 500A and 500B constituting one pixel includes a second opening 514 positioned to correspond to a part of the driving circuit, and at least one sub-pixel ( 500B) does not include the second opening 514 .

In FIG. 11 , red (R), white (W), and green (G) sub-pixels among red (R), white (W), blue (B), and green (G) sub-pixels form the second opening 514 . Although the sub-pixel 500A including the sub-pixel 500A and the blue (B) sub-pixel is illustrated as the sub-pixel 500B not including the second opening 514 , the present invention is not limited thereto. For example, two of the red (R), white (W), blue (B), and green (G) subpixels may be the subpixels 500B that do not include the second opening 514 .

The second opening 514 may be positioned to correspond to at least one of the two or more transistors included in the driving circuit DC. 11 illustrates that the second opening 514 is positioned to correspond to the driving transistor DTR in the driving circuit, but is not limited thereto. For example, the second opening 514 may be positioned to correspond to one of the other transistors (the switching transistor SWT and the sensing transistor STR) together with the driving transistor DTR.

12 is a plan view of a sub-pixel when the sub-pixel of FIG. 11 represents white.

As shown in FIG. 12 , when expressing white, a sub-pixel 500A used to implement a target color temperature of white and a sub-pixel 500B not used are separated, and the second sub-pixel 500A used is The second opening 514 may not be disposed in the subpixel 500B in which the opening 514 is disposed and not used. That is, the sub-pixel 500A including the second opening 514 is a sub-pixel that emits light by being used to implement a target color temperature of white when expressing white, and does not include the second opening 514 . The sub-pixel 500B may be a sub-pixel that does not emit light because it is not used to implement a target color temperature of white when expressing white. Therefore, the unused sub-pixel 500B applies a black bank to the region except for the first opening 512, and does not include the second opening 514 corresponding to the driving transistor DTR, so that it is affected by NBTS. It can be made to be relatively less affected by PBTS.

In other words, since the data driver 120 shown in FIG. 1 does not provide a data voltage to the sub-pixel 500B not including the second opening 514 , the sub-pixel 500B not including the second opening 514 . does not emit light and only the remaining sub-pixels 500A emit light to express white.

As described above, when a black bank is applied to the bank layer 510 of each sub-pixel 500A and 500B, both internal and external light are blocked, thereby improving the NBTS characteristics shown in FIG. 5 by light. However, when a black bank is applied to the bank layer 510 to both the sub-pixels used and the sub-pixels that are not used as described above in order to implement the target color temperature of white, the NBTS characteristics of the sub-pixels that do not emit light are shown in FIG. 5 . As shown in Fig. 6, the PBTS characteristics of the emitting subpixels are less affected by the NBTS and deteriorate.

According to the presence or absence of light emission for realizing the target color temperature of white in the above-described embodiment, the application of the black bank to the bank layer 510 of the subpixels constituting one pixel is different, so that the threshold voltage of the transistor is shifted according to the presence or absence of light emission. Characteristics can be improved.

A color filter layer is disposed in the subpixel 500A including the second opening 514 and the subpixel 500B not including the second opening 514 to correspond to the first opening 512 as shown in FIG. 9 . can be In the subpixel 500A including the second opening 514, the color filter layer is not disposed up to the second opening 514, but in the subpixel 500B not including the second opening 514, the color filter layer is one of the transistors. At least one, for example, a transistor (eg, a driving transistor) located closest to the first opening 512 may be disposed. That is, in the subpixel 500B not including the second opening 514 , the bank layer 510 is disposed throughout the driving circuit and the color filter layer is closest to at least one of the transistors, for example, the first opening 512 . The transistors (eg, driving transistors) are disposed to minimize the light emitted from the first opening 512 from reaching the corresponding transistor.

As described above, according to the presence or absence of light emission for realizing the target color temperature of white in the above-described embodiment, whether a black bank is applied to the bank layer 510 of the sub-pixels constituting one pixel and whether a black bank is applied and the arrangement of the color filter layer are different depending on whether there is light emission The shift characteristic of the threshold voltage of the transistor can be improved according to

As a result, when the target color temperature of white is realized, the shift characteristics of the threshold voltages of different transistors are improved depending on whether light is emitted or not, thereby maintaining the same lifetime for each sub-pixel.

3rd embodiment

13 to 16 are cross-sectional views of four sub-pixels constituting one pixel according to another exemplary embodiment.

Referring to FIG. 13 , one pixel P may include two or more sub-pixels, for example, four sub-pixels 600A, 600B, 600C, and 600D.

The sub-pixels 600A, 600B, 600C, and 600D are sequentially positioned on the thin film transistor 620 positioned on the substrate 610 , the insulating film 630 positioned on the thin film transistor 620 , and the insulating film 630 . It may include an organic light emitting diode (OLED) including a first electrode (not shown), an organic layer 660 and a second electrode 670 positioned as . The sub-pixels 600A, 600B, 600C, and 600D include an insulating layer 630 and a bank layer 650 disposed on the first electrode. As the bank layer 650 , a black bank made of at least one selected from organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel may be applied.

In addition, the thin film transistor 620 includes a semiconductor layer 622 , a gate insulating film 623 formed on the semiconductor layer 622 , a gate electrode 624 formed on the gate insulating film 623 , and an interlayer formed on the gate electrode 624 . It may include a source electrode/drain electrode 626 formed on the insulating layer 625 and the interlayer insulating layer 625 and connected to the semiconductor layer 622 through a contact hole.

One pixel P is disposed to correspond to the thin film transistor 620 of at least one of the first sub-pixels 600A and 600D among the sub-pixels 600A, 600B, 600C, and 600D, but at least one second sub-pixel and a light blocking layer 690 not disposed to correspond to the thin film transistor 620 of the pixels 600B and 600C.

In the first sub-pixels 600A and 600D, a light blocking layer 690 formed to correspond to the thin film transistor 620 may be disposed between the substrate 610 and the thin film transistor 620 . A buffer layer 692 may be disposed between the substrate 610 and the light blocking layer 690 .

The light blocking layer 690 protects the semiconductor layer 622 from external light, and functions to prevent the external light from being reflected to reduce visibility, improve luminance, and reduce contrast characteristics. Here, the external light introduced through the substrate 610 may be non-polarized light. This is because, when external light is introduced into the semiconductor layer 622 of the thin film transistor 620 , electrical properties or chemical properties may change.

Meanwhile, in the second sub-pixels 600B and 600C, the light blocking layer 690 is not disposed to correspond to the thin film transistor 620 .

When the black bank is applied to the bank layer 650 , the negative shift level of the threshold voltage is reduced by blocking internal light, but the positive shift level of the threshold voltage can be relatively increased compared to before the black bank in the bank layer 650 . have.

When the thin film transistor 620 is driven, the threshold voltage is positively shifted by the PBTS, and when the thin film transistor 620 is not driven, the threshold voltage is negatively shifted by the NBTS. In order to negatively shift the threshold voltage during non-driving, the stress caused by light may change to a high level.

When the black bank is applied to the bank layer 650 , stress caused by light is blocked, thereby preventing negative shift. Since the threshold voltage does not shift negatively even during non-driving, the level of the positive shift is relatively increased. Accordingly, a color having a high positive shift level of the threshold voltage may increase more than the compensation margin.

In the embodiment described with reference to FIG. 13 , when the black bank is applied to the bank layer 650 , light blocking is minimized for subpixels (eg, white subpixels and blue subpixels) having a large positive shift level of the threshold voltage. The light blocking layer 690 may not be disposed to correspond to the thin film transistor 620 like one of the second sub-pixels 600B and 600C.

Referring to FIG. 14 , the second sub-pixels 600B and 600C may further include a first transparent conductive layer 694 at a position corresponding to the light blocking layer 690 of the first sub-pixels 600A and 600D. have. That is, the second sub-pixels 600B and 600C may include a first transparent conductive layer 694 positioned to correspond to at least one transistor. The first transparent conductive layer 694 may be made of the same material as the above-described first electrode, but is not limited thereto and may be any transparent conductive material.

As described above, since the second sub-pixels 600B and 600C additionally include the first transparent conductive layer 694 at a position corresponding to the light-blocking layer 690 of the first sub-pixels 600A and 600D, while transmitting external light. It is possible to prevent heterogeneity in electrical characteristics with the light blocking layer 690 of the first sub-pixels 600A and 600D. For example, the light blocking layer 690 of the first sub-pixels 600A and 600D blocks external light and removes static electricity generated in the substrate 610 or inside, and the second sub-pixels 600B and 600C ) of the first transparent conductive layer 694 may serve to remove static electricity generated inside or on the substrate 610 while transmitting external light.

As shown in FIG. 14 , only the second sub-pixels 600B and 600C do not include the first transparent conductive layer 694 at a position corresponding to the light blocking layer 690 of the first sub-pixels 600A and 600D. As shown in FIG. 15 , a second transparent conductive layer 696 is added to all of the sub-pixels 600A, 600B, 600C, and 600D constituting one pixel P under the thin film transistor 620 . can be included as In this case, the light blocking layer 690 of the first sub-pixels 600A and 600D may be positioned on the second transparent conductive layer 696 . In this case, the second transparent conductive layer 696 is disposed only at a position corresponding to the light blocking layer 690 of the first sub-pixels 600A and 600D, and in the second sub-pixels 600B and 600C, the first sub-pixels 600A and 600D. ) may be located only at a position corresponding to the light blocking layer 690 . As a result, in the first sub-pixels 600A and 600D, the light blocking layer 690 and the second transparent conductive layer 696 constitute a multilayer structure, and in the second sub-pixels 600B and 600C, the second transparent conductive layer 696 is formed. constitutes a single layer.

For example, in the first sub-pixels 600A and 600D, the multi-layered second transparent conductive layer 696 and the light blocking layer 690 block external light while removing static electricity generated from the substrate 610 or the inside. In the second sub-pixels 600B and 600C, the single-layered second transparent conductive layer 696 may serve to remove static electricity generated in the substrate 610 or the inside while transmitting external light.

The second transparent conductive layer 696 is disposed only at a position corresponding to the light blocking layer 690 of the first sub-pixels 600A and 600D, and in the second sub-pixels 600B and 600C to the first sub-pixels 600A and 600D. Although it has been described as being positioned only at a position corresponding to the light blocking layer 690 of Since the second transparent conductive layer 696 is disposed on the entire surface of the substrate 610 , a patterning process using a mask may be omitted.

As shown in FIG. 16 , all of the sub-pixels 600A, 600B, 600C, and 600D constituting one pixel P have a light blocking layer 690 and a second transparent conductive layer 696 on the substrate 610 . may include As shown in FIG. 15 , instead of the second transparent conductive layer 696 being positioned on the substrate 610 , as shown in FIG. 16 , the second transparent conductive layer 696 is a light blocking layer 690 . The first sub-pixels 600A and 600D are positioned on the light-blocking layer 690 , and the light-blocking of the first sub-pixels 600A and 600D is located in the second sub-pixels 600B and 600C where the light-blocking layer 690 is not disposed. It may be located on the substrate 610 at a position where the layer 690 is disposed.

In the same manner as described with reference to FIG. 15 , the second transparent conductive layer 696 is disposed only at a position corresponding to the light blocking layer 690 of the first sub-pixels 600A and 600D, and the second sub-pixels 600B and 600C. It may be located only at a position corresponding to the light blocking layer 690 of the first sub-pixels 600A and 600D, or may be disposed on the entire surface of the substrate 610 to omit the patterning process using a mask. As a result, in the first sub-pixels 600A and 600D, the light blocking layer 690 and the second transparent conductive layer 696 constitute a multilayer structure, and in the second sub-pixels 600B and 600C, the second transparent conductive layer 696 is formed. constitutes a single layer.

For example, in the first sub-pixels 600A and 600D, the multi-layered light blocking layer 690 and the second transparent conductive layer 696 block external light while removing static electricity generated from the substrate 610 or the inside. In the second sub-pixels 600B and 600C, the single-layered second transparent conductive layer 696 may serve to remove static electricity generated in the substrate 610 or the inside while transmitting external light.

According to the above-described embodiments, the upper portion of the thin film transistor is not exposed to light emitted from the organic light emitting diode through an opening separately disposed in the bank layer or a light blocking layer is not disposed under the thin film transistor, so that the threshold voltage of the thin film transistor is not provided. It relieves the degree of positive shift of the thin film transistor, and since the thin film transistor operates precisely because the threshold voltage of the thin film transistor is not shifted to positive or negative, it is possible to prevent 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", "compose" or "have" described above mean that the corresponding component may be embedded unless otherwise stated, so it 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 in the context of the related art, and are not 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. Therefore, 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 equivalent range should be construed as being included in the scope of the present invention.

200, 400, 500A, 500B, 600A to 600C: subpixel
210, 310, 510, 650: bank layer
212, 312, 512: first opening
214, 514: second opening
P: pixel
OLED: organic light emitting diode
DTR: drive transistor
STR: Sensing Transistor
SWT: Switching Transistor

Claims (18)

at least one pixel composed of two or more subpixels positioned in regions where two or more data lines and two or more gate lines intersect;
At least one sub-pixel of the sub-pixels,
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;
two or more transistors for applying a current to the organic light emitting diode or sensing a characteristic value of another transistor; and
a first opening defining a light emitting region and a second opening positioned corresponding to at least one of the two or more transistors, and a bank layer to which a black bank is applied;
The organic layer is exposed on a lower surface of the second opening, and the first electrode is positioned so as not to overlap the lower surface of the second opening. The method of claim 1,
The bank layer is an organic light emitting display 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,
At least one transistor positioned corresponding to the second opening is a driving transistor for driving the organic light emitting diode or a sensing transistor for sensing a characteristic value of the driving transistor. The method of claim 1,
All of the sub-pixels include the second opening in the bank layer. 4. The method of claim 3,
Further comprising a substrate on which the two or more transistors are located,
At least one sub-pixel of the sub-pixels,
Further comprising a light blocking layer at a position corresponding to the driving transistor and the sensing transistor,
The light blocking layer is positioned between the substrate and a driving transistor included in the at least one subpixel. According to claim 1,
At least one sub-pixel among the sub-pixels including the second opening is a sub-pixel used to represent white. Two or more sub-pixels constituting one pixel,
a thin film transistor positioned on a substrate;
an insulating film positioned on the thin film transistor;
an organic light emitting diode including a first electrode, an organic layer, and a second electrode sequentially positioned on the insulating layer; and
a bank layer positioned on the insulating film and the first electrode to define a light emitting region;
a light blocking layer disposed to correspond to the thin film transistor of at least one first sub-pixel among the sub-pixels but not disposed to correspond to the thin film transistor of at least one second sub-pixel;
the light blocking layer is disposed corresponding to a thin film transistor of a first subpixel including a first color subpixel among the two or more subpixels;
The light blocking layer is not disposed to correspond to a thin film transistor of a second subpixel including a second color subpixel different from the first color subpixel among the two or more subpixels, and the light blocking layer is removed from the substrate. An organic light emitting display device in which light is transmitted through a thin film transistor. 8. The method of claim 7,
The bank layer is an organic light emitting display device comprising at least one selected from an organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel. 8. The method of claim 7,
The second sub-pixel may further include a first transparent conductive layer positioned to correspond to the at least one transistor at a position where the light blocking layer of the first sub-pixel is disposed. 8. The method of claim 7,
The subpixels further include a second transparent conductive layer under the transistor,
The light blocking layer of the first sub-pixel is positioned above or below the second transparent conductive layer. 11. The method of claim 10,
The second transparent conductive layer is disposed on the entire surface of the substrate. two or more data lines and two or more gate lines disposed in a direction crossing each other; and
a pixel including two or more sub-pixels positioned in regions where the data lines and the gate lines intersect, respectively;
At least one sub-pixel of the sub-pixels,
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;
two or more transistors for applying a current to the organic light emitting diode or sensing a characteristic value of another transistor; and
a first opening defining a light emitting region and a second opening positioned corresponding to at least one of the two or more transistors, and a bank layer to which a black bank is applied;
The organic layer is exposed on a lower surface of the second opening, and the first electrode does not overlap the lower surface of the second opening. 13. The method of claim 12,
The bank layer is an organic light emitting display panel comprising at least one selected from an organic insulating material black resin, graphite powder, gravure ink, black spray, and black enamel. 13. The method of claim 12,
At least one transistor positioned corresponding to the second opening is a driving transistor for driving the organic light emitting diode or a sensing transistor for sensing a characteristic value of the driving transistor. 13. The method of claim 12,
All of the sub-pixels include the second opening in the bank layer. 15. The method of claim 14,
Further comprising a substrate on which the two or more transistors are located,
At least one sub-pixel of the sub-pixels,
Further comprising a light blocking layer at a position corresponding to the driving transistor and the sensing transistor,
The light blocking layer is positioned between the substrate and a driving transistor included in the at least one sub-pixel. 17. The method of claim 16,
An organic light emitting display panel in which the light blocking layer is not disposed at a position corresponding to the driving transistor and the sensing transistor in at least one other subpixel of the subpixels. 13. The method of claim 12,
At least one sub-pixel among the sub-pixels including the second opening is a sub-pixel used to express white.

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