Patent ID: 12219822

DETAILED DESCRIPTION

Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings. Although the invention may be modified in various manners and have several exemplary embodiments, exemplary embodiments are illustrated in the accompanying drawings and will be mainly described in the specification. However, the scope of the invention is not limited to the exemplary embodiments and should be construed as including all the changes, equivalents and substitutions included in the spirit and scope of the invention.

In the drawings, thicknesses of a plurality of layers and areas are illustrated in an enlarged manner for clarity and ease of description thereof. When a layer, area, or plate is referred to as being “on” another layer, area, or plate, it may be directly on the other layer, area, or plate, or intervening layers, areas, or plates may be present therebetween. Conversely, when a layer, area, or plate is referred to as being “directly on” another layer, area, or plate, intervening layers, areas, or plates may be absent therebetween. Further when a layer, area, or plate is referred to as being “below” another layer, area, or plate, it may be directly below the other layer, area, or plate, or intervening layers, areas, or plates may be present therebetween. Conversely, when a layer, area, or plate is referred to as being “directly below” another layer, area, or plate, intervening layers, areas, or plates may be absent therebetween.

The spatially relative terms “below”, “beneath”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device illustrated in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in the other direction and thus the spatially relative terms may be interpreted differently depending on the orientations.

Throughout the specification, when an element is referred to as being “connected” to another element, the element is “directly connected” to the other element, or “electrically connected” to the other element with one or more intervening elements interposed therebetween. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It will be understood that, although the terms “first,” “second,” “third,” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, “a first element” discussed below could be termed “a second element” or “a third element,” and “a second element” and “a third element” may be termed likewise without departing from the teachings herein.

“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an ideal or excessively formal sense unless clearly defined at the present specification.

Some of the parts which are not associated with the description may not be provided in order to specifically describe exemplary embodiments and like reference numerals refer to like elements throughout the specification.

Hereinafter, an embodiment will be described with reference toFIGS.1and2.

FIG.1illustrates a plan view of a pixel of an organic light emitting diode (“OLED”) display device according to an embodiment.FIG.2is a cross-sectional view taken along line I-I′ ofFIG.1.

An OLED display device101according to embodiment illustrated inFIG.1includes a plurality of pixels PX. Herein, the term “pixel PX” may refer to a smallest unit for displaying images. Referring toFIGS.1and2, the pixel PX may include a switching thin film transistor TFT1, a driving thin film transistor TFT2, an OLED170and a capacitor Cst.

The pixel PX may generate a light of a predetermined color, for example, one of red, green or blue. In some implementations, the color of the light generated in the pixel PX may be, for example, cyan, magenta, yellow, or the like.

The pixel PX may be connected to a gate line GL, a data line DL, and a driving voltage line DVL. The gate line GL may extend in one direction. The data line DL may extend in another direction that crosses the gate line GL. Referring toFIG.1, the driving voltage line DVL may extend in a direction that is substantially the same as a direction in which the data line DL extends. The gate line GL may transmit a scan signal, the data line DL may transmit a data signal, and the driving voltage line DVL may transmit a driving voltage.

The thin film transistors TFT1and TFT2may include the driving thin film transistor TFT2for controlling the OLED170and the switching thin film transistor TFT1for switching the driving thin film transistor TFT2. For example, each pixel PX may include two thin film transistors TFT1and TFT2. In various implementations, each pixel PX may include a different number of thin film transistors and/or capacitors, for example, one thin film transistor and one capacitor or three or more thin film transistors and two or more capacitors.

A portion in which the thin film transistors TFT1and TFT2, the gate line GL, the data line DL, the driving voltage line DVL and the capacitor Cst are disposed may be referred to as a wiring portion. Each of the gate line GL, the data line DL, the driving voltage line DVL and the capacitor Cst may be referred to as a wiring. In addition, the thin film transistors TFT1and TFT2may be one of the wirings or a part of the wirings.

The switching thin film transistor TFT1may include a first gate electrode GE1, a first source electrode SE1, a first drain electrode DE1, and a first semiconductor layer SM1. The first gate electrode GE1may be connected to the gate line GL, and the first source electrode SE1may be connected to the data line DL.

The first drain electrode DE1may be connected to a first capacitor plate CS1through a fifth contact hole CH5and a sixth contact hole CH6. The switching thin film transistor TFT1may transmit a data signal that is applied to the data line DL to the driving thin film transistor TFT2according to a scan signal applied to the gate line GL.

The driving thin film transistor TFT2may include a second gate electrode GE2, a second source electrode SE2, a second drain electrode DE2, and a second semiconductor layer SM2. The second gate electrode GE2may be connected to the first capacitor plate CS1. The second source electrode SE2may be connected to the driving voltage line DVL. The second drain electrode DE2may be connected to a first electrode171through a third contact hole CH3.

An organic light emitting layer172may be disposed on the first electrode171, and a second electrode173may be disposed on the organic light emitting layer172. A common voltage may be applied to the second electrode173, and the organic light emitting layer172may generate a light according to an output signal of the driving thin film transistor TFT2.

The capacitor Cst may be connected between the second gate electrode GE2and the second source electrode SE2of the driving thin film transistor TFT2. The capacitor Cst may charge and maintain a signal input to the second gate electrode GE2of the driving thin film transistor TFT2. The capacitor Cst may include the first capacitor plate CS1connected to the first drain electrode DE1through the sixth contact hole CH6and a second capacitor plate CS2connected to the driving voltage line DVL.

The thin film transistors TFT1and TFT2and the OLED170may be disposed on a substrate111.

The substrate111may include, for example, an insulating material such as glass, plastic, quartz, or the like. The material for the substrate111may be selected, for example, from materials that are excellent in mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, water resistance, or the like.

A buffer layer may be disposed on the substrate111. The buffer layer may substantially prevent diffusion of impurities into the switching thin film transistor TFT1and the driving thin film transistor TFT2.

The first semiconductor layer SM1and the second semiconductor layer SM2may be disposed on the substrate111. The first semiconductor layer SM1and the second semiconductor layer SM2may include a semiconductor material and may serve as active layers of the switching thin film transistor TFT1and the driving thin film transistor TFT2, respectively. Each of the first semiconductor layer SM1and the second semiconductor layer SM2may include a source area SA, a drain area DA, and a channel area CA between the source area SA and the drain area DA.

The first semiconductor layer SM1and the second semiconductor layer SM2may include, for example, amorphous silicon or polycrystalline silicon, or may include, for example, an oxide semiconductor. For example, each of the first semiconductor layer SM1and the second semiconductor layer SM2may include an inorganic semiconductor material or an organic semiconductor material. The source area SA and the drain area DA may be doped with an n-type impurity or a p-type impurity.

A gate insulating layer121may be disposed on the first semiconductor layer SM1and the second semiconductor layer SM2. The gate insulating layer121may protect the first semiconductor layer SM1and the second semiconductor layer SM2. The gate insulating layer121may include an organic insulating material or an inorganic insulating material.

The first gate electrode GE1and the second gate electrode GE2may be disposed on the gate insulating layer121. The first gate electrode GE1and the second gate electrode GE2may be disposed so as to overlap the channel areas CA of the first semiconductor layer SM1and the second semiconductor layer SM2, respectively. In addition, the first capacitor plate CS1may be disposed on the gate insulating layer121. The second gate electrode GE2and the first capacitor plate CS1may have a unitary structure.

An insulating interlayer122may be disposed on the first gate electrode GE1, the second gate electrode GE2, and the first capacitor plate CS1. The insulating interlayer122may include an organic insulating material or an inorganic insulating material.

The first source electrode SE1, the first drain electrode DE1, the second source electrode SE2, and the second drain electrode DE2may be disposed on the insulating interlayer122. The second drain electrode DE2may contact the drain area DA of the second semiconductor layer SM2through a first contact hole CH1defined at the gate insulating layer121and the insulating interlayer122. The second source electrode SE2may contact the source area SA of the second semiconductor layer SM2through a second contact hole CH2defined at the gate insulating layer121and the insulating interlayer122. The first source electrode SE1may contact the first semiconductor layer SM1through a fourth contact hole CH4defined at the gate insulating layer121and the insulating interlayer122. The first drain electrode DE1may contact the first semiconductor layer SM1through the fifth contact hole CH5defined at the gate insulating layer121and the insulating interlayer122.

The data line DL, the driving voltage line DVL and the second capacitor plate CS2may be disposed on the insulating interlayer122. The second capacitor plate CS2and the driving voltage line DVL may have a unitary structure.

A protection layer130may be disposed on the first source electrode SE1, the first drain electrode DE1, the second source electrode SE2and the second drain electrode DE2. The protection layer130may protect the switching thin film transistor TFT1and the driving thin film transistor TFT2and also may planarize upper surfaces thereof.

According to an exemplary embodiment, the protection layer130may include a polymer resin. For example, the protection layer130may include polyimide (PI). Referring toFIGS.1and3, the protection layer130may include recessed portions211,212,213, and214and a trench pattern710. The protection layer130, the recessed portions211,212,213, and214, and the trench pattern710will be described below.

The first electrode171may be disposed on the protection layer130. The first electrode171may be, for example, an anode. The first electrode171may be, for example, a pixel electrode.

The first electrode171may be connected to the second drain electrode DE2of the driving thin film transistor TFT2through the third contact hole CH3defined at the protection layer130.

A pixel defining layer190that divides a light emission area may be disposed on the protection layer130.

The pixel defining layer190may include a polymer organic material. For example, the pixel defining layer190may include at least one of a polyimide (PI) resin, a polyacrylic resin, a PET resin, and a PEN resin. For example, the pixel defining layer190may include a polyimide (PI) resin.

The pixel defining layer190may define an opening195, and the first electrode171may be exposed from the pixel defining layer190through the opening195. In addition, a light emission area of the OLED170, which may also be referred to as a “pixel area” may be defined by the opening195.

Referring toFIGS.1and2, the pixel defining layer190may expose an upper surface of the first electrode171. The pixel defining layer190may protrude from the first electrode171along a periphery of each of the pixels PX. The first electrode171may overlap at least a portion of the pixel defining layer190and does not overlap the pixel defining layer190at the opening195. For example, the opening195may be defined as an area above the first electrode171that does not overlap the pixel defining layer190. In addition, a boundary at which the pixel defining layer190contacts the first electrode171at the opening195may be referred to as an edge191of the opening195.

The first electrode171may have conductivity, and may be a transmissive electrode, a transflective electrode, or a reflective electrode. When the first electrode171is a transmissive electrode, the first electrode171may include a transparent conductive oxide. For example, the transparent conductive oxide may include at least one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium tin zinc oxide (ITZO). When the first electrode171is a transflective electrode or a reflective electrode, the first electrode171may include at least one of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and Cu.

The organic light emitting layer172may be disposed on the first electrode171. For example, the organic light emitting layer172may be disposed on the first electrode171at the opening195. The organic light emitting layer172may be disposed on a sidewall of the opening195defined by the pixel defining layer190and on the pixel defining layer190.

The organic light emitting layer172may include a light emitting material. In addition, the organic light emitting layer172may include a host and a light emitting dopant. The organic light emitting layer172may be manufactured in a general method, using a suitable material. For example, the organic light emitting layer172may be formed through various methods such as a vacuum deposition method, a spin coating method, a cast method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, a laser induced thermal imaging (LITI) method, or the like.

At least one of a hole injection layer (HIL) and a hole transport layer (HTL) may be disposed between the first electrode171and the organic light emitting layer172.

The second electrode173may be disposed on the organic light emitting layer172.

The second electrode173may be a common electrode and may be a cathode.

The second electrode173may be a transmissive electrode, a transflective electrode, or a reflective electrode.

When the second electrode173is a transmissive electrode, the second electrode173may include at least one of Li, Ca, LiF/Ca, LiF/Al, Al, Mg, BaF, Ba, Ag, and Cu. For example, the second electrode173may include a mixture of Ag and Mg.

When the second electrode173is a transflective electrode or a reflective electrode, the second electrode173may include at least one of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, Mo, Ti, and Cu. In some implementations, the second electrode173may further include a transparent conductive layer including, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium-zinc-tin oxide (IZTO), in addition to the transflective electrode or the reflective electrode.

At least one of an electron transport layer (ETL) and an electron injection layer (EIL) may be disposed between the organic light emitting layer172and the second electrode173.

When the OLED170is a top emission type, the first electrode171may be a reflective electrode and the second electrode173may be a transmissive electrode or a transflective electrode. When the OLED170is a bottom emission type, the first electrode171may be a transmissive electrode or a transflective electrode, and the second electrode173may be a reflective electrode.

According to an embodiment, the OLED170may be a top emission type, the first electrode171may be a reflective electrode, and the second electrode173may be a transflective electrode.

Hereinafter, the protection layer130will be described in more detail.

According to an embodiment, the protection layer130may include a trench pattern710formed outside the first electrode171and recessed portions211,212,213, and214located below the first electrode171and overlapping the opening195.

The trench pattern710may include a plurality of trenches711extending along a first direction.

When a polymer resin has fluidity in a thermosetting process of the polymer resin for forming the protection layer130, the trench pattern710may serve to substantially prevent the polymer resin from flowing to the recessed portions211,212,213, and214, which could impair the pattern stability of the recessed portions211,212,213, and214. For example, when thermosetting of the polymer resin for forming the protection layer130proceeds, the polymer resin may have fluidity in the thermosetting process. If such a polymer resin having fluidity were to flow to the recessed portions211,212,213, and214, the recessed portions211,212,213, and214could be buried, and a depth of the recessed portions211,212,213, and214could decrease or the recessed portions211,212,213, and214could disappear. If the recessed portions211,212,213, and214were to be buried in such a manner, the effect of substantially preventing color shift and white angular dependency (WAD) by the recessed portions211,212,213, and214might not be achieved.

In order to substantially prevent such burying or a reduction of the depth of the recessed portions211,212,213, and214, the trench pattern710may be formed outside of the first electrode171. When the trench pattern710is formed outside of the first electrode171, polymer resin that has obtained fluidity may flow to the trench pattern710in the thermosetting process. Thus, the polymer resin may be substantially prevented from flowing to the recessed portions211,212,213, and214. Accordingly, the pattern stability of the recessed portions211,212,213, and214may be ensured and the effect of substantially preventing color shift and WAD may be achieved by the recessed portions211,212,213, and214.

Each of the plurality of trenches711may be spaced apart in a plan view from the first electrode171. Accordingly, the trench711may be disposed apart in a plan view from the edge191of the opening195located inside the first electrode171.

A distance TL between the first electrode171and the trench711may depend on a size of the OLED170, a size of the first electrode171, a distance between adjacent ones of the first electrodes171, or the like. For example, the trench711may be spaced apart from the first electrode171by a distance of about 1 μm to about 5 μm. For example, the trench711may be spaced apart from the first electrode171by a distance of about 1.5 μm to about 2.5 μm.

The trench711may have a predetermined width TW. The width TW of the trench711may vary depending on the size of the OLED170, the size of the first electrode171, the distance between adjacent ones of the first electrodes171, or the like.

The trench711may have a concave cross-section. The trench711may have a predetermined depth d3, which may vary depending on a thickness of the protection layer130. As examples, the trench711may have a depth d3of about 0.2 μm to about 1.0 μm or a depth d3of about 0.3 μm to about 0.7 μm. For example, when the protection layer130has a thickness of about 1 μm or more, the trench711may have a thickness of about 1 μm or more. For example, when the protection layer130has a thickness of about 0.3 μm or less, the trench711may have a thickness of about 0.3 μm or less.

Adjacent ones of the trenches711may be arranged at a predetermined pitch TP. The pitch TP between the plurality of trenches711may vary depending on a planar area of the first electrode171and a size of the OLED170.

The protection layer130may include recessed portions211,212,213, and214located at an area overlapping the opening195, which is defined by the pixel defining layer190. The first electrode171is also located above the recessed portions211,212,213, and214. Accordingly, the first electrode171may include corresponding recessed portions.

The recessed portions211,212,213, and214may be spaced apart in a plan view from the edge191of the opening195. For example, an edge BR of the recessed portions211,212,213, and214may spaced apart in a plan view from the edge191of the opening195.

The term “edge191of the opening195” may refer to a boundary of the opening195, and may be defined as a boundary at which the pixel defining layer190contacts the first electrode171. The edge191of the opening195may be defined as a boundary at which the protection layer130and the pixel defining layer190overlap each other in a plan view.

Referring toFIGS.1and2, the recessed portions211,212,213, and214may be absent below the edge191of the opening195. For example, the recessed portions211,212,213, and214may not overlap the edge191of the opening195.

The protection layer130may have a substantially same height h1with respect to a surface of the substrate111at a boundary where the protection layer130overlaps the pixel defining layer190. For example, the protection layer130may have a substantially same height h1along the edge191of the opening195.

For example, the protection layer130may have a height difference of about 0.1 μm or less with respect to the surface of the substrate111at the boundary where the protection layer130overlaps the pixel defining layer190.

According to an exemplary embodiment, the edge191of the opening195may also have a substantially same height with respect to the surface of the substrate111. For example, the edge191of the opening195may have a height difference of about 0.1 μm or less with respect to the surface of the substrate111.

The pixel defining layer190may be formed through a patterning process such as a photolithography method. For example, the edge191of the opening195may correspond to a boundary of a pattern. In this regard, if a lower surface of the pattern boundary were to be non-uniform, that is, not flat, it could difficult to form a uniform pattern. Accordingly, the edge191of the opening195may have a uniform height to be flat, and occurrence of pattern defects in the process of forming the pixel defining layer190may be substantially prevented.

The recessed portions211,212,213, and214may be spaced apart from the edge191of the opening195such that the edge191of the opening195may be flat.

According to this embodiment, the recessed portions211,212,213, and214may be spaced apart in a plan view from the edge191of the opening195by a distance of about 0.5 μm to about 5.0 μm. Accordingly, a distance V1between the recessed portions211,212,213, and214and the edge191of the opening195may be determined by a distance between the edge191of the opening195and the edge BR of the recessed portions211,212,213, and214.

The distance V1between the recessed portions211,212,213, and214and the edge191of the opening195may vary depending on the size of the OLED170. For example, the recessed portions211,212,213, and214may be spaced apart in a plan view from the edge191of the opening195by a distance in a range from about 0.5 μm to about 2.0 μm, or may be spaced apart in a plan view from the edge191of the opening195by a distance of about 5.0 μm or more.

At least a part of the edge BR of the recessed portions211,212,213, and214may be parallel to the edge191of the opening195. Referring toFIG.1, at least one side of the edge BR of the recessed portions211,212,213, and214may be parallel to the edge191of the opening195.

When the edge BR of the recessed portions211,212,213, and214and the edge191of the opening195are parallel to each other, the distance V1between the recessed portions211,212,213, and214and the edge191of the opening195may be easily maintained. Accordingly, the pattern may be formed uniformly in the process of forming the pixel defining layer190.

The width W1of the recessed portions211,212,213, and214may vary depending on the size of the OLED170, the size of the first electrode171, the number of the recessed portions, or the like. According to an embodiment, the recessed portions211,212,213, and214may have a width W1in a range from about 1.0 μm to about 2.0 μm.

A depth d1of the recessed portions211,212,213, and214may vary depending on the thickness of the protection layer130. In some implementations, the recessed portions211,212,213, and214may have a depth d1of about 0.2 μm to about 1.0 μm. For example, the recessed portions211,212,213, and214may have a depth d1of about 0.3 μm to about 0.7 μm. When the protection layer130has a thickness of about 1 μm or more, the recessed portions211,212,213, and214may have a thickness of about 1 μm or more. When the protection layer130has a thickness of about 0.3 μm or less, the recessed portions211,212,213, and214may have a thickness of about 0.3 μm or less.

When the recessed portions211,212,213, and214have such a width W1and depth d1, light generated in the organic light emitting layer172may resonate in a lateral direction. Accordingly, color shift and WAD depending on the viewing angle may be substantially prevented or mitigated.

Adjacent ones of the recessed portions211,212,213, and214may be arranged at a pitch P1of about 1 μm to about 6 μm. The pitch between the recessed portions211,212,213, and214may vary depending on the planar area of the first electrode171and the size of the OLED170.

The first electrode171may contact the driving thin film transistor TFT2through the third contact hole CH3defined at the protection layer130. Referring toFIGS.1and2, the recessed portions211,212,213, and214may have a depth less than a depth d2of the third contact hole CH3. In some implementations, the recessed portions211,212,213, and214may have a depth substantially equal to the depth of the third contact hole CH3or may have a depth greater than the depth of the third contact hole CH3.

Referring toFIG.2, the protection layer130may include two or more recessed portions211,212,213, and214overlapping one opening195. The first electrode171may be disposed above the plurality of recessed portions211,212,213, and214. The first electrode171may overlap the plurality of recessed portions211,212,213, and214. Accordingly, the first electrode171may include a recessed portion corresponding to the recessed portions211,212,213, and214.

FIGS.3,4,5,6, and7are respective plan views illustrating arrangements of a first electrode171, a recessed portion221and a trench pattern of one pixel according to some embodiments.

In order to avoid redundancy, descriptions of components described above may be omitted.

InFIGS.3,4,5,6, and7, “R” refers to a red pixel, “G” refers to a green pixel, and “B” refers to a blue pixel. An edge191of an opening195shown inFIGS.3,4,5,6, and7is located in an area of the first electrode171.

The first electrode171may be formed in various planar shapes as desired. For example, the first electrode171as illustrated inFIGS.3,4,5,6, and7has an octagonal planar shape. As illustrated inFIGS.3,4,5,6, and7, openings195of respective pixels R, G, and B may have shapes and planar areas that are different from each other according to the color of the respective pixels R, G, and B.

The protection layer130may include a plurality of recessed portions221having a dot shape. Each of the recessed portions221may have a circular planar shape. The plurality of recessed portions221may be arranged within a boundary defined by the edge191of the opening195. The plurality of recessed portions221may be arranged symmetrically or asymmetrically with respect to a central portion of the opening195. The planar areas of the plurality of recessed portions221may vary according to the color of the pixels R, G, and B where the respective recessed portions221are located. A total planar area of the plurality of recessed portions221may be proportional to a planar area of the opening195in which the corresponding recessed portions221are located. For example, as illustrated inFIGS.3,4,5,6, and7, when the blue pixel B has a greatest planar area and the green pixel G has a smallest planar area, the recessed portion221at the opening195of the blue pixel B may have a greatest total planar area, and the recessed portion at the opening195of the green pixel G may have a smallest total planar area.

The trench pattern720includes a plurality of trenches721,722,723,724, and725extending along a first direction.

According to the embodiments illustrated inFIGS.3,4,5,6, and7, the plurality of trenches721,722,723,724, and725may be disposed apart planarly from the first electrode171. Accordingly, the trenches721,722,723,724, and725, in a plan view, may be disposed apart from the edge191of the opening195that is disposed inside the first electrode171.

A distance TL between the first electrode171and the trenches721,722,723,724, and725may vary depending on a size of an OLED170, a size of the first electrode171, a distance between adjacent ones of the first electrodes171, or the like. The trenches721,722,723,724, and725may be spaced from the first electrode171by a distance of about 1 μm to about 5 μm. For example, the trenches721,722,723,724, and725may be spaced apart from the first electrode171by a distance of about 1.5 μm to about 2.5 μm.

The trenches721,722,723,724, and725have a predetermined width TW. The width TW of the trenches721,722,723,724, and725may vary depending on the size of the OLED170, the size of the first electrode171, the distance between adjacent ones of the first electrodes171, or the like.

Adjacent ones of the trenches721,722,723,724, and725may be arranged at a predetermined pitch TP. The pitch TP between the trenches721,722,723,724, and725may vary depending on a planar area of the first electrode171and the size of the OLED170.

According to as the embodiment illustrated inFIG.3, the trenches721may extend with a straight line shape along the first direction. The first direction may be a direction parallel to one of a gate line and a data line. In some implementations, the first direction may be a direction that forms a predetermined angle with respect to one of the gate line and the data line. For example, according to the embodiment illustrated inFIG.4, the plurality of trenches722may extend with a straight line shape along a direction at a predetermined angle with respect to one of the gate line or the data line.

In the embodiment illustrated inFIG.4, at least a part of an edge TBR of the trenches721and722may be parallel to an edge of the first electrode171. At least one side of the edge TBR of the trenches721and722may be parallel to the edge of the first electrode171. For example, as illustrated inFIG.3, at least one side of the edge TBR of the trenches721and722may be parallel to an edge of the first electrode171of the green pixel G. In addition, as illustrated inFIG.4, at least one side of the edge TBR of the trenches721and722may be parallel to an edge of the first electrode171of the red and blue pixels R and B. In some implementations, and the edge TBR of the trenches721and722may not be parallel to any edge of the first electrode171.

When the edge TBR of the trenches721and722and the edge of the first electrode171are parallel to each other, it may be easy to maintain the distance TL between the first electrode171and the trenches721and722, such that a pattern may be uniformly formed in the process of forming the pixel defining layer190.

According to the embodiment illustrated inFIG.5, a plurality of trenches723may include a stem trench extending in a straight line shape along the first direction and a branch trench branching from the stem trench in a second direction that crosses the first direction. The first direction may be a direction forming a predetermined angle with respect to one of the gate line and the data line, and the second direction may be a direction perpendicular to the first direction. For example, the trench pattern720may be in the form of a broken mesh.

At least a part of an edge TBR of the trench723may be parallel to the edge of the first electrode171. At least one side of the edge TBR of the trench723may be parallel to the edge of the first electrode171. For example, at least one side of the edge TBR of the trench723may be parallel to an edge of the first electrode171of the green pixel G. In addition, at least one side of the edge TBR of the trench723may be parallel to an edge of the first electrode171of the red and blue pixels R and B. In some implementations, the edge TBR of the trench723may not be parallel to any edge of the first electrode171.

When the edge TBR of the trench723and the edge191of the opening195are parallel to each other, it may be easy to maintain a distance TL between the first electrode171and the trench723, such that a pattern may be uniformly formed in the process of forming the pixel defining layer190.

According to as the embodiment illustrated inFIG.6, the trench724may extend substantially in a wavy shape along the first direction.

In such an exemplary embodiment, the first direction may be a direction parallel to one of the gate line and the data line. In some implementations, the first direction may be a direction that forms a predetermined angle with respect to one of the gate line and the data line.

According to as the embodiment illustrated inFIG.7, the trench725may have a dot shape. For example, the trench725may have one of a circular shape and a polygonal shape. For example, the trench725may have a circular shape.

FIG.8illustrates a cross-sectional view according to anFIG.9illustrates a plan view of an arrangement of a first electrode, a recessed portion and a trench pattern of a pixel according to the embodiment.

Hereinafter, in order to avoid redundancy, descriptions of components described above will not be repeated.

According to the embodiment illustrated inFIGS.8and9, a protection layer130may include a trench pattern730formed outside a first electrode171and a recessed portion221located below the first electrode171and overlapping an opening195.

The trench pattern730may have a concave cross-section and may be disposed apart from the first electrode171in a plan view. A distance TL between the trench pattern730and the first electrode171may vary depending on a size of an OLED170, a size of the first electrode171, a distance between adjacent ones of the first electrodes171, or the like. For example, the trench pattern730may be spaced apart from the first electrode171by a distance in a range from about 1 μm to about 5 μm. For example, the trench pattern may be spaced apart from the first electrode171by a distance in a range from about 1.5 μm to about 2.5 μm.

According to the embodiment illustrated inFIGS.8and9, the trench pattern730may surround the first electrode171on a plane and may have a unitary structure.

The trench pattern730may have a shape substantially identical to a shape of the pixel defining layer190in a plan view. In some implementations, the trench pattern730may have a planar area less than a planar area of the pixel defining layer190in a plan view. For example, the trench pattern730may not overlap the opening195and may be disposed apart from an edge191of the opening195.

The trench pattern730may have a height less than a height of the protection layer130, at a boundary where the protection layer130overlaps the pixel defining layer190, with respect to a surface of the substrate111. For example, the trench pattern730may have a height less than a height of the edge191of the opening195.

FIGS.10A,10B,10C, and10Dare plan views illustrating arrangements of a first electrode171, recessed portions231,241,242,243,244,251,252,253, and254and a trench pattern740of a pixel according to embodiments. Hereinafter, in order to avoid redundancy, descriptions of components described above will not be repeated.

Referring toFIGS.10A,10B,10C, and10D, the trench pattern740may include a plurality of trenches741,742,743, and744. The plurality of trenches741,742,743, and744may extend along a first direction and may be disposed apart from each other. For example, the plurality of trenches741,742,743, and744may be arranged in parallel to each other.

Adjacent ones of the trenches741,742,743, and744may be arranged at a predetermined pitch TP. The pitch TP of the plurality of trenches741,742,743, and744may vary depending on a planar area of the first electrode171and a size of an OLED170.

The trenches741,742,743, and744may have a predetermined width TW. The width TW of the trenches741,742,743, and744may vary depending on the size of the OLED170, the size of the first electrode171, a distance between adjacent ones of the first electrodes171, or the like.

Referring toFIG.10A, the plurality of recessed portions231may have a circular planar shape. In some implementations, the recessed portion231may have other shapes such as a polygonal, elliptical or linear planar shape.

Referring toFIG.10B, one first electrode171may be disposed above two recessed portions241and242each having a linear shape. For example, a protection layer130may include two recessed portions241and242defined at one opening195. Referring toFIG.10B, the two recessed portions241and242may each have a linear shape extending in a vertical direction with respect to the drawings. For example, the two recessed portions241and242extend parallel to each other in a substantially same direction and may have a symmetrical or substantially identical shape.

Each of the recessed portions241and242may be spaced from an edge191of the opening195by a predetermined distance V2. Each of the recessed portions241and242may have a width W2and a length Ln2. The two recessed portions241and242may be arranged at a predetermined pitch P2.

Referring toFIG.10C, a plurality of recessed portions243and244that are asymmetric may be located below one first electrode171. For example, the protection layer130includes a first recessed portion243and a second recessed portion244overlapping one opening195. A planar area of the first recessed portion243may be greater than a planar area of the second recessed portion244. In order to substantially prevent the first electrode171from contacting a wiring located below the first electrode171at the second recessed portion244, a planar area of the second recessed portion244may be small such that a depth of the second recessed portion244is less than a depth of the first recessed portion243.

For example, a length Ln21of the first recessed portion243may be greater than a length Ln22of the second recessed portion244, and a width W21of the first recessed portion243may be greater than a width W22of the second recessed portion244.

Referring toFIG.10D, the protection layer130may include a plurality of recessed portions251,252,253, and254, each having a linear shape. The plurality of linear-shaped recessed portions251,252,253, and254may overlap one opening195and may be arranged radially.

For example, four linear-shaped recessed portions251,252,253, and254overlapping one opening195may be defined in the protection layer130. In such an exemplary embodiment, an angle θCbetween extending directions of the recessed portions251,252,253, and254may be in a range from about 60 degrees to about 120 degrees. For example, the four recessed portions251,252,253, and254may be arranged such that the angle θCbetween the extending directions is about 90 degrees. As such, the recessed portions251,252,253, and254may be arranged symmetrically with respect to a central portion of the opening195.

In an exemplary embodiment, when the recessed portions241and242are arranged to extend in one direction as illustrated inFIGS.10B and10C, color shift and WAD in a direction perpendicular to the extending direction of the recessed portions241and242may be improved, whereas the degree of improvement in color shift and WAD in a direction substantially equal to the extending direction of the recessed portions241and242may be insignificant. For example, when the recessed portions241and242are arranged as illustrated inFIGS.10B and10C, WAD and color shift in a horizontal direction with respect to the drawings may be improved while the improvement in WAD and color shift in a vertical direction may be insignificant.

On the other hand, when the recessed portions251,252,253, and254are arranged radially as illustrated inFIG.10D, color shift and WAD may be improved in both the horizontal direction and the vertical direction with respect to the drawings.

FIG.11illustrates a cross-sectional view illustrating an OLED display device according to an embodiment.

The OLED display device illustrated inFIG.11includes a thin film encapsulation layer140disposed on a second electrode173to protect an OLED170. The thin film encapsulation layer140may serve to substantially prevent moisture or oxygen from permeating into the OLED170.

The thin film encapsulation layer140may include at least one inorganic layer141and143and at least one organic layer142that are alternately disposed. The thin film encapsulation layer140illustrated inFIG.11may include two inorganic layers141and143and one organic layer142.

The inorganic layers141and143may include at least one of a metal oxide, a metal oxynitride, a silicon oxide, a silicon nitride and a silicon oxynitride. The inorganic layers141and143may be formed using various suitable methods. For example, the inorganic layers141and143may be formed through methods such as a chemical vapor deposition (CVD) or an atomic layer deposition (ALD).

The organic layer142may include, for example, a polymer-based material. The organic layer142may be formed by a suitable method. For example, the organic layer142may be formed through a thermal deposition process. The thermal deposition process for forming the organic layer142may be performed within a temperature range that does not damage the OLED170.

The inorganic layers141and143, which have a high density of a thin film, may substantially prevent or efficiently reduce permeation of undesirable substances such as moisture or oxygen. Permeation of moisture and oxygen into the OLED170may be largely prevented by the inorganic layers141and143.

Moisture and oxygen that have passed through the inorganic layers141and143may further be blocked by the organic layer142. The organic layer142may also serve as a buffer layer to reduce stress between each of the inorganic layers141and143, in addition to the moisture permeation preventing function. Further, the organic layer142may have planarizing characteristics. Accordingly, an uppermost surface of the thin film encapsulation layer140may be planarized by the organic layer142.

The thin film encapsulation layer140may have a small thickness. Accordingly, an OLED display device having a significantly small thickness may be provided. Such an OLED display device may have excellent flexibility.

FIG.12illustrates a cross-sectional view of an OLED display device according to an embodiment.

The OLED display device illustrated inFIG.12includes a sealing member150disposed on a second electrode173to protect an OLED170.

The sealing member150may include a light transmissive insulating material such as glass, quartz, ceramic and plastic. The sealing member150may have a plate shape and may be attached to a substrate111to protect the OLED170.

A filler160may be disposed between the OLED170and the sealing member150. The filler160may include an organic material, for example, a polymer. A protection layer including a metal or an inorganic material may be disposed on the OLED170to protect the OLED170.

Referring toFIG.12, the OLED display device may include a spacer197on a pixel defining layer190. The spacer197may serve to maintain a distance between the substrate111and the sealing member150. The spacer197may protrude toward an upper portion of the pixel defining layer190, for example, a portion that is opposite to a protection layer130.

Similar to the pixel defining layer190, the spacer197may include a polyacrylic resin or a polyimide (PI) resin.

The spacer197and the pixel defining layer190may have a unitary structure. For example, the pixel defining layer190and the spacer197may be unitarily formed through a photolithography process using a photosensitive material. In some implementations, the pixel defining layer190and the spacer197may be formed sequentially or separately, or may include different materials, respectively.

The spacer197may have one of a truncated pyramid shape, a prism shape, a truncated cone shape, a cylinder shape, a hemisphere shape, or a hem i-spheroid shape.

Hereinafter, stages of a method of manufacturing the OLED display device101according toFIGS.1to3will be described with reference toFIGS.13A,13B,13C,13D,13E,13F,13G,13H,13I and13J.FIGS.13A,13B,13C,13D,13E,13F,13G,13H,13I and13Jillustrate views of stages of a process of manufacturing the OLED display device101ofFIGS.1to3.

Referring toFIG.13A, a driving thin film transistor TFT2and a capacitor Cst may be formed on a substrate111. Wirings such as a switching thin film transistor TFT1, a gate line GL, a data line DL and a driving voltage line DVL may be formed on the substrate111as well.

Referring toFIG.13B, a photosensitive material may be applied over an entire surface of the substrate111including the driving thin film transistor TFT2such that a photosensitive material layer131is formed. Examples of the photosensitive material may include a photodegradable polymer resin. Examples of the photodegradable polymer resin may include a polyimide (PI) resin.

Referring toFIG.13C, a first pattern mask301may be disposed above the photosensitive material layer131, spaced apart from the photosensitive material layer131.

The first pattern mask301may include a mask substrate310and a light blocking pattern320on the mask substrate310. The light blocking pattern320may include at least three areas, each having different light transmittances. Such a first pattern mask301is also referred to as a “half tone mask.”

The mask substrate310may include suitable material having light transmittance and mechanical strength. For example, the mask substrate310may be a transparent glass or plastic substrate.

The light blocking pattern320may be formed by selectively applying a light blocking material to the mask substrate310. The blocking pattern320may include a light transmissive portion321, a light blocking portion322and transflective portions323and324.

The light transmissive portion321is a portion through which light is transmitted. The light transmissive portion321may be located above an area to be defined with a third contact hole CH3.

The light blocking portion322may be a portion at which light transmission is blocked. The light blocking portion322may be formed by applying a light blocking material to the mask substrate310.

The transflective portions323and324are portions through which an incident light is partially transmitted. The transflective portions323and324may be located above an area to be defined with recessed portions210and220and an area to be formed with a trench pattern710. For example, the transflective portions323and324may have a structure in which light transmissive areas323aand324aand light blocking slits323band324bare alternately disposed. The light transmittance of the transflective portions323and324may be adjusted by adjusting a pitch between the light transmissive areas323aand324aand the light blocking slits323band324b, respectively.

A transflective portion323located above the area to be defined with the recessed portions211and212and a transflective portion324located above the area to be formed with the trench pattern710may have a substantially equal light transmittance or may have different light transmittances. Depths of the recessed portions211and212and a depth of the trench pattern710may be respectively adjusted by adjusting the light transmittance.

In addition, in order to define the recessed portions211and212having a small planar area, the transflective portion323may include only one light transmissive area323a. The planar area and depth of the recessed portions211and212may be adjusted by adjusting a planar area of the light transmissive area323a.

The light transmittance of the transflective portions323and324may be adjusted by adjusting a concentration of the light blocking material.

The photosensitive material layer131may be patterned through exposure using the first pattern mask301illustrated inFIG.13C, such that a protection layer130including the recessed portions210and220and the trench pattern710is formed (seeFIG.13D).

For example, the photosensitive material layer131may be exposed and then developed, such that a pattern such as the recessed portions210and220, the trench pattern710and the third contact hole CH3is formed. Referring toFIG.13D, after the exposure and development, the photosensitive material layer131may be thermally cured to form the protection layer130. Polymeric resins forming the photosensitive material layer131may partially flow in the thermosetting process, thus forming gently curved recessed portions210and220.

When the polymer resin forming the photosensitive material layer131has fluidity during the thermosetting process of the photosensitive material layer131, if the polymer resin were to flow to the recessed portions211and212, the recessed portions211and212could be be filled with the polymer resin to be buried. If the recessed portions211and212were to be filled, the depths of the recessed portions211and212could become shallow or the recessed portions211and212could disappear. If the depths of the recessed portions211and212were to become shallow or the recessed portions211and212were to disappear, the effect of substantially preventing color shift and WAD by the recessed portions211and212could be reduced or might not be achieved.

However, according to embodiments, the recessed portions211and212may be substantially prevented from being filled due to the forming the trench pattern710including a plurality of trenches711around the first electrode171. For example, the polymer resin having fluidity in the thermosetting process of the photosensitive material layer131may flow toward the trench pattern710to substantially prevent the recessed portions211and212from being filled. Accordingly, pattern stability of the recessed portions211and212may be ensured and the recessed portions211and212may have a predetermined depth and a predetermined width.

As such, the trench pattern710may serve to maintain the pattern stability of the recessed portions211and212in the thermosetting process for forming the protection layer130.

Referring toFIG.13E, the first electrode171may be formed on the protection layer130. The first electrode171may be electrically connected to a second drain electrode DE2through the third contact hole CH3.

The first electrode171may also be disposed on the recessed portions211and212. However, the first electrode171is not disposed on the trench pattern710.

Referring toFIG.13F, a photosensitive material layer199for forming a pixel defining layer may be disposed on the substrate111including the first electrode171and the protection layer130.

The photosensitive material layer199for forming a pixel defining layer may include a photodegradable polymer resin. Examples of the photodegradable polymer resin may include a polyimide (PI)-based resin, a polyacrylic resin, a PET resin, and a PEN resin. For example, the photosensitive material layer199may include a polyimide (PI)-based resin.

Referring toFIG.13G, a second pattern mask401may be disposed above the photosensitive material layer199.

The second pattern mask401may include a mask substrate410and a light blocking pattern420on the mask substrate410. The mask substrate410may include a transparent glass or plastic substrate. The light blocking pattern420may include a light transmissive portion421and a light blocking portion422.

The light transmissive portion421may be a portion through which light is transmitted. The light transmissive portion421may be located above an area to be defined with an opening195. The light blocking portion422may be a portion where the transmission of light is blocked. The light blocking portion422may be located above an area other than the area to be defined with the opening195.

The photosensitive material layer199may be patterned through a photolithography method using the second pattern mask201, as illustrated inFIG.13G. For example, the photosensitive material layer199may be exposed and then developed such that the opening195is defined.

Referring toFIG.13H, the patterned photosensitive material layer199may be thermally cured such that a pixel defining layer190is formed. Polymeric resins forming the photosensitive material layer199may partially flow during the thermosetting process.

The opening195and an edge191of the opening195may be defined by the pixel defining layer190. The first electrode171may be exposed from the pixel defining layer190by the opening195. The pixel defining layer190may expose an upper surface of the first electrode171and may protrude along a circumference of the first electrode171. The pixel defining layer190may overlap an end portion of the first electrode171, and the opening195may be located above the first electrode171. The pixel defining layer190may be disposed above the trench pattern710such that an upper portion of the trench pattern710becomes flat.

In an implementation, the edge191of the opening195does not overlap the recessed portions211and212. The edge191of the opening195may be spaced apart from the recessed portions211and212. For example, an edge BR of the recessed portions211and212and the edge191of the opening195may be spaced apart from each other.

When a pattern is formed through a photolithography method, if a bottom surface of a boundary area of the pattern is not flat, it could be difficult to form a uniform pattern. According to embodiments, a recessed portion or an uneven portion are not formed at the edge191of the opening195, and the edge191of the opening195is located on a flat surface. Accordingly, occurrence of pattern defects may be substantially reduced or prevented in the process of forming the pixel defining layer190.

Referring toFIG.13I, an organic light emitting layer172may be formed on the first electrode171that is exposed by the opening195of the pixel defining layer190. The organic light emitting layer172may be formed by a deposition method.

Referring toFIG.13J, a second electrode173may be formed on the organic light emitting layer172. The second electrode173may also formed on the pixel defining layer190. The second electrode173may be formed by a deposition method.

FIG.14illustrates a view showing a relative height of a protection layer at an opening according to a general art and an embodiment.

“A” represents a depth of a recessed portion of a protection layer at which a trench pattern is not formed according to a conventional art, and “B” represents a depth of a recessed portion of a protection layer at which a trench pattern is formed according to an exemplary embodiment.

Referring toFIG.14, it may be appreciated that the depth of the recessed portion is deeper in “B” than the depth of the recessed portion in “A.” For example, in the case of “A,” when the polymer resin has fluidity, the polymer resin flows into the recessed portion, and the recessed portion is filled with the polymer resin to be buried. On the other hand, in the case of “B,” the trench pattern is formed around the first electrode171. It may be identified that the recessed portion is substantially prevented from being filled. For example, the polymer resin, which has fluidity in the thermosetting process of the photosensitive material layer131, flows to the trench pattern, substantially preventing filling of the recessed portion. Accordingly, the pattern stability of the recessed portion is ensured, and the recessed portion may have a predetermined depth and width.

As set forth hereinabove, the OLED display devices according to one or more exemplary embodiments may include a recessed portion and a trench pattern formed at the protection layer. The recessed portion may serve to substantially prevent a color shift depending on the viewing angle, and the trench pattern may improve the pattern stability of the recessed portion. The OLED display devices that include such recessed portion and trench pattern may have excellent display characteristics.

By way of summation and review, general OLED display devices have a multi-layer structure that includes an OLED. However, such a structure may produce a color shift depending on the viewing angle when emitting a light which is generated in the OLED to the outside. This color shift may degrade display quality of the OLED display device. Accordingly, in order for the OLED display device to have excellent display quality, it is desirable to substantially prevent the occurrence of color shift in the OLED display device.

Embodiments provide an organic light emitting diode (“OLED”) display device in which a color shift depending on a viewing angle is reduced to have improved display characteristics.

Embodiments provide an OLED display device having excellent pattern stability and provide a method of manufacturing the OLED display device.

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope there as set forth in the following claims.