Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.
In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.
1 is a cross-sectional view of an OLED display according to an exemplary embodiment of the present invention. 2 is an enlarged cross-sectional view of the X region of FIG. FIG. 2B is a partial plan view of the overcoat layer, the first electrode, and the pattern layer in the X region of FIG.
1 and 2, an OLED display 100 according to an exemplary embodiment includes a substrate 110, a thin film transistor 120, a color filter 150, an overcoat layer 160, a pattern layer 337, And an organic light emitting diode 140.
The organic light emitting diode display 100 shown in FIGS. 1 and 2A is a bottom emission organic light emitting diode display. However, the OLED display 100 according to an exemplary embodiment may be a top emission type OLED display in which the color filter 150 is located on the opposite side of the substrate 110.
A thin film transistor 120 including a gate electrode 121, an active layer 122, a source electrode 123 and a drain electrode 124 is disposed on a substrate 110. [
A gate electrode 121 is disposed on the substrate 110 and a gate insulating layer 131 for insulating the gate electrode 121 and the active layer 122 on the gate electrode 121 and the substrate 110 And an active layer 122 is disposed on the gate insulating layer 131. An etch stopper 132 is disposed on the active layer 122. An active layer 122 and an etch stop layer A source electrode 123 and a drain electrode 124 are disposed on the phosphor 132. The source electrode 123 and the drain electrode 124 are electrically connected to the active layer 122 in such a manner as to be in contact with the active layer 122 and are disposed on a partial area of the etch stopper 132. The etch stopper 132 may not be disposed.
For convenience of description, only the thin film transistors among the various thin film transistors that can be included in the OLED display 100 are shown in this specification. The thin film transistor 120 is also referred to herein as an inverted staggered transistor in which the gate electrode 121 is located on the opposite side of the source electrode 123 and the drain electrode 124 with respect to the active layer 122. [ Structure or a bottom gate structure, but the gate electrode 121 is located on the same side as the source electrode 123 and the drain electrode 124 with respect to the active layer 122, Thin film transistors of the structure can also be used.
A passivation layer 133 is disposed on the thin film transistor 120 and a color filter 150 is disposed on the passivation layer 133.
2A, the passivation layer 133 is illustrated as being planarized over the thin film transistor 120, but the passivation layer 133 is not planarized over the thin film transistor 120, but is disposed along the surface shape of the underlying elements It is possible.
The color filter 150 may be one of a red color filter, a green color filter, and a blue color filter for color conversion of light emitted from the organic light emitting layer 142.
The color filter 150 is disposed on the passivation layer 133 at a position corresponding to the light emitting region. Here, the light emitting region means a region where the organic light emitting layer 142 emits light by the first electrode 141 and the second electrode 143, and the color filter 150 is disposed at a position corresponding to the light emitting region, Means that the color filter 150 is disposed to prevent the light emitted from the light emitting regions from intermingling with each other to prevent blurring and ghosting.
For example, the color filter 150 is disposed to overlap the light emitting region, and may have a size smaller than the light emitting region. The position and size of the color filter 150 may be determined not only by the size and position of the light emitting region but also by the distance between the color filter 150 and the first electrode 141 and the distance between the color filter 150 and the overcoat layer 160 The distance between the convex portions 162, the distance between the light emitting region and the light emitting region, and the like.
An overcoat layer 160 is disposed on the color filter 150 and the passivation layer 133. Although the passivation layer 133 is shown in FIG. 2A as being included in the organic light emitting diode display 100, the passivation layer 133 may not be used and the overcoat layer 160 may be directly disposed on the thin film transistor 120 have. The color filter 150 may be disposed at any position between the overcoat layer 160 and the substrate 110. The color filter 150 may be disposed on the passivation layer 133, .
The overcoat layer 160 includes a plurality of convex portions 162 arranged to overlap with the color filter 150 and a first connecting portion 161 connecting the convex portions 162 adjacent to each other. 2A is a cross-sectional view of a plurality of hexagonal convex portions 162. FIG. The first connecting portion 161 is a lower portion between the convex portions 162 adjacent to each other. The overcoat layer 160 functions as a planarization layer in a portion where the plurality of convex portions 162 are not disposed.
As shown in FIG. 2B, each of the convex portions 162 and the first connecting portions 161 may have a generally hexagonal shape in plan view, but not limited thereto, and may have various shapes such as hemispherical shape, semi-ellipsoidal shape, . The plurality of convex portions 162 may be arranged in a hexagonal honeycomb structure on a plane. In other words, one convex portion 162 having a hexagonal shape and another convex portion 162 adjacent to the other convex portion 162 can be disposed in an integrally formed hexagonal honeycomb structure by sharing one side.
The organic light emitting device 140 and the bank 136 including the first electrode 141, the organic light emitting layer 142, and the second electrode 143 are disposed on the overcoat layer 160. At this time, although not shown, it is possible to prevent the outgassing from the overcoat layer 160 from diffusing to the organic light emitting diode 140 while keeping the morphology of the protrusion 162 of the overcoat layer 160 as it is, An insulating second passivation layer (not shown) having a refractive index similar to that of the first electrode 141 may be added between the overcoat layer 160 and the first electrode 141.
Specifically, a first electrode 141 for supplying one of electrons or holes to the organic light emitting layer 142 is disposed on the overcoat layer 160. The first electrode 141 may be an anode, a pixel electrode, or an anode in a normal organic light emitting diode (OLED), or may be a cathode, a pixel electrode, or a cathode in an inverted OLED.
The first electrode 141 may be connected to the source electrode 123 of the thin film transistor 120 through a contact hole formed in the overcoat layer 160. The first electrode 141 is connected to the source electrode 123 on the assumption that the thin film transistor 120 is an N-type thin film transistor. However, when the thin film transistor 120 is a P-type thin film transistor The first electrode 141 may be connected to the drain electrode 124. The first electrode 141 may directly contact the organic light emitting layer 142 or may be electrically connected to the organic light emitting layer 142 via a conductive material.
The first electrode 141 is disposed in a shape following the morphology of the surface of the overcoat layer 160. Accordingly, the first electrode 141 has a convex morphology at the convex portion 162 of the overcoat layer 160. [
A bank layer 136 including an overcoat layer 160 and an opening 136a exposing the first electrode 141 on the first electrode 141 is disposed. The bank layer 136 serves to separate adjacent pixel (or sub pixel) regions, and may be disposed between adjacent pixel (sub pixel) regions. The convex portion 162 and the first connection portion 161 of the overcoat layer 160 are disposed so as to overlap the opening portion 136a of the bank layer 136. [ The convex portion 162 of the overcoat layer 160 and the first connection portion 161 are disposed to overlap the color filter 150 so that the convex portion 162 of the overcoat layer 160 and the first connection portion 161 overlap the color filter 150 and overlap with the opening 136a of the bank layer 136 in the upper part.
An organic light emitting layer 142 is disposed on the first electrode 141 and a second electrode 143 is disposed on the organic light emitting layer 142 to supply one of electrons or holes to the organic light emitting layer 142. The organic light emitting layer 142 is arranged in a tandem white structure in which a plurality of organic light emitting layers are stacked to emit white light. The organic light emitting layer 142 includes a first organic light emitting layer that emits blue light and a second organic light emitting layer that is disposed on the first organic light emitting layer and emits light of a color that is mixed with blue and becomes white. The second organic luminescent layer may be, for example, an organic luminescent layer emitting yellowgreen light. The organic light emitting layer 142 may include only an organic light emitting layer that emits one of blue light, red light, and green light. At this time, the color filter 150 may not be included. The second electrode 143 may be a cathode, a common electrode, or a cathode in a normal organic light emitting device (OLED), or may be an anode, a common electrode, or an anode in an inverted OLED.
2A, the thickness of the organic light emitting layer 142 between the convex portion 162 of the overcoat layer 160 and the first connection portion 161 is greater than the thickness of the convex portion 162 of the overcoat layer 160, The thickness of the organic light emitting layer 142 may be smaller than the thickness of the organic light emitting layer 142. [ The thickness of the organic light emitting layer 142 may be the smallest at a position where the slope of the organic light emitting layer 142 is largest between the convex portion 162 of the overcoat layer 160 and the first connecting portion 161.
For example, when the organic light emitting layer 142 is formed by vapor deposition, the organic light emitting layer 142 deposited in a direction perpendicular to the substrate 110 may have a shape along the morphology of the overcoat layer 160. The thickness d1 of the organic light emitting layer 142 between the first electrode 141 and the second electrode 142 is the thinnest at a position where the slope of the organic light emitting layer 142 is the largest. The thicknesses d2 and d3 of the organic light emitting layer 142 between the first electrode 141 and the second electrode 142 at the lowest position of the organic light emitting layer 142 are the thickest.
An organic light emitting layer 142 is formed between the convex portion 162 of the overcoat layer 160 and the first connection portion 161 in terms of the amount of emission of the organic light emitting layer 142 depending on the thickness d1, d2, d3, etc. of the organic light emitting layer 142. [ 142 may be greater than the amount of light emitted per unit area of the organic light emitting layer 142 at the bottom of the convex portion 162 or the top of the first connection portion 161. Particularly, the light emission amount of the organic light emitting layer 142 may be largest at a position where the slope of the organic light emitting layer 142 is largest between the convex portion 162 of the overcoat layer 160 and the first connection portion 161.
The organic light emitting layer 142 and the second electrode 143 may be formed of the same material as the first electrode 141, the organic light emitting layer 142, and the second electrode 143, which have a shape conforming to the morphology of the surface of the overcoat layer 160 And the morphology of the upper surface of the one electrode 141 is followed. As a result, the shape of the organic light emitting diode 140 can be realized using the convex portion 162 of the overcoat layer 160.
When the organic light emitting device 140 has a microlens array structure for improving the external light extraction efficiency, the convex portions 162 of the overcoat layer 160 are formed on the surface of the organic light emitting device 140, ), The convex curvature appears. At this time, the shortest thickness d1, which is the shortest distance from the organic light emitting layer 142 between the first electrode 141 and the second electrode 143, becomes thinner and the effective light emitting area Y That is, a region between the convex portion 162 of the overcoat layer 160 and the first connection portion 161 occurs. When the organic light emitting diode 140 is driven, the electric field is locally concentrated in the efficient light emitting region and a main current path is formed to cause the main light emission. In the convex portion 162 of the overcoat layer 160, ) So that almost no light is extracted. In this inefficient light emitting region Z, although light is consumed, almost no light can be extracted, and the efficiency of extracting external light is lowered.
The organic light emitting diode display 100 according to one embodiment may be included in the overcoat layer 160 of the micro lens array pattern having a convex shape on the color filter 150. The light emitted from the organic light emitting layer 142 is totally reflected within the first electrode 141 and the organic light emitting layer 142 and is trapped by the microlens array structure inserted at an angle smaller than the total reflection critical angle, The luminous efficiency can be increased.
At this time, the advancing angle of the light emitted from the organic light emitting layer 142 is changed by the microlens array pattern, but the light advancing angle can be clearly different even by the minute difference of the microlens array shape.
The shape of the convex portion 162 of the overcoat layer 160 is formed through a process such as photolithography. When the heat treatment process performed at this time is controlled, the morphology of the convex portion 162 of the overcoat layer 160 Can be adjusted.
More specifically, it is as follows. In order to form the convex portion 162 of the overcoat layer 160, a photoresist is applied and patterned in a convex shape through a photolithography process, followed by heat treatment. At this time, the shape of the convex portion 162 of the overcoat layer 160 can be formed by performing the stepwise heat treatment in two steps, rather than performing the heat treatment at once. For example, the intermediate heat treatment at about 100 ° C or higher and 130 ° C or lower should be performed before the final heat treatment at about 200 ° C or higher and 250 ° C or lower.
At this time, the time for performing the intermediate heat treatment is related to the morphology of the convex portion 162 of the overcoat layer 160. As the time for performing the intermediate heat treatment increases, the shape of the convex portion 162 of the finally formed overcoat layer 160 increases. If only the final heat treatment is performed without any time for performing the intermediate heat treatment, the shape of the convex portion 162 of the overcoat layer 160 disappears and the overcoat layer 160 is planarized.
Using this tendency, various organic light emitting display devices having different morphologies of convex portions 162 of the overcoat layer 160 were manufactured. When the convex portion 162 of the overcoat layer 160 has a certain morphology, that is, when the convex portion 162 of the overcoat layer 160 has a specific aspect ratio, the organic light- It was tested whether it could operate with efficiency.
The organic light emitting diode display 100 according to an exemplary embodiment of the present invention may be totally reflected in the organic light emitting diode 140 through a light path that varies depending on the shape of the convex portion 162 of the overcoat layer 160 So that the trapped lights are extracted to the outside.
Since the optical path change depending on the shape of the convex portion 162 of the inserted overcoat layer 160 for improving the external light extraction efficiency is a major factor for improving the light extraction efficiency, the overcoat layer 160 A height H (Height), an aspect ratio (A / R), a full width half maximum (F), and a half height Height width ratio Rm (Ratio (Rm)) of the aspect ratio (F_A / R (= H / F)), the slope of MLA = (F_A / R) / (A / R))).
3A is a conceptual representation of the parameters that determine the shape of the convex portion 162 of the overcoat layer 160. FIG. FIG. 3B shows the parameters determining the shape of the convex portion of the overcoat layer in the organic light emitting display according to one embodiment. 3C is a view for explaining the concept of the gap G at the bottom of the convex portion of the overcoat layer.
3A and 3B, the diameter D of the convex portion 162 of the overcoat layer 160 indicates the length of the convex portion 161 at the bottom position, and the height H indicates the length of the convex portion 162, To the bottom of the first connection part 161. [0064] The half height width F means the length of the convex portion 162 at a half position of the height of the convex portion 162 as shown in Fig. The aspect ratio A / R of the convex portion 162 means a value obtained by dividing the height H of the convex portion 162 by the radius D / 2 of the convex portion 162.
The convex portion 162 may have a hexagonal shape with a diameter D of 1 to 5 占 퐉 and a height H of 1 to 4 占 퐉.
The aspect ratio A / R of the convex portion 161 of the overcoat layer 160 has a value of about 0.2 to 0.8 when the aspect ratio A / R of the convex portion 161A of the overcoat layer 160 is It can be confirmed that the rate of current efficiency increase is higher than that in the case of having a value exceeding 0.8. Rather, if the aspect ratio A / R of the convex portion 162 of the overcoat layer 160 has a value of more than about 0.8, the current efficiency increasing rate tends to be lowered rather. In particular, when the aspect ratio of the convex portion 162 of the overcoat layer 160 has a value between about 0.4 and 0.7, it can be seen that the current efficiency increase rate is the maximum.
The surface on which the organic light emitting diode 140 is disposed in the organic light emitting diode display 100 according to an exemplary embodiment is formed such that the aspect ratio A / R of the convex portion 162 of the overcoat layer 160 is about 0.2 or more And may be the top surface of the overcoat layer 160 having a value between about 0.8 and less. Or the surface on which the organic light emitting diode 140 is disposed in the organic light emitting diode display 100 according to an exemplary embodiment of the present invention is formed such that the aspect ratio A / R of the convex portion 162 of the overcoat layer 160 is (Not shown) that follows the morphology of the overcoat layer 160 having a value between about 0.2 and about 0.8. That is, the overcoat layer 160 or the second passivation layer (not shown) at this time is a gentle non-planar screen whose surface has an aspect ratio (A / R) of between about 0.2 and about 0.8, The device 140 is formed on a gentle unflattened screen having an aspect ratio of between about 0.2 and about 0.8 and the anode 141, the organic light emitting layer 142, and the cathode 143 are formed of a gentle non-planar screen morphology As shown in FIG.
The first connecting portion 161 of the convex portion 162 of the overcoat layer 160 may be formed to have the same shape as that of the convex portion 162 of the overcoat layer 160, It can be formed to have a gentle slope. When the overcoat layer 160 is formed such that the aspect ratio A / R of the convex portion 162 of the overcoat layer 160 has a value of not less than 0.2 and not more than 0.8 according to this method, The organic light emitting device 140 including the first electrode 141, the organic light emitting layer 142 and the second electrode 143 and the bank 136 may be formed on the substrate 160.
When only the aspect ratio A / R is applied as a parameter defining the shape of the convex portion 162 of the overcoat layer 160, only the diameter D and the height H are defined by the same aspect ratio A / R The shape of the convex portion 162 of the overcoat layer 160 is significantly different when the values defined by other variables such as the half height width F and the gap G between the convex portions are changed.
4A to 4D are cross-sectional views comparing the shapes of convex portions of the overcoat layer 160 having the same aspect ratio.
4A shows the positions of the first to third regions C, B, and A included in each of the equal portions when the convex portion 162 of the overcoat layer 160 is trisected on the basis of the height.
4B to 4D are diagrams illustrating the relationship between the diameter D of the convex portion 162 of the overcoat layer 160 and the height H of the overcoat layer 160, FIG. The aspect ratio A / R of the convex portion 162 of the overcoat layer 160 shown in FIGS. 4B to 4D is about 0.6. As described above, the convex portion 162 of the overcoat layer 160, Of not less than 0.2 and not more than 0.8.
4B shows the overcoat layer 160 in which the maximum slope Smax having the maximum slope is located in the first region C when the height H of the convex portion 162 of the overcoat layer 160 is about the third And the convex portion 162 is shown. At this time, the inclination S of the convex portion 162 means an angle between the tangential line of the lower surface of the convex portion 162 and the horizontal plane as shown in FIG. 4A. At this time, the maximum slope Smax means a slope at which the angle between the tangential line of the lower surface of the convex portion 162 and the horizontal plane is the maximum.
4C shows the convex portion 162 of the overcoat layer 160 where the maximum slope Smax is located in the second region B when the height H of the convex portion 162 of the overcoat layer 160 is the third ).
4D shows the convex portion 162 of the overcoat layer 160 where the maximum slope Smax is located in the third region A when the height H of the convex portion 162 of the overcoat layer 160 is taken as the third ).
Although the aspect ratios A / R of the convex portions 162 of the overcoat layer 160 shown in FIGS. 4B to 4D are the same or similar to each other, depending on the shape of the convex portions 162 of the overcoat layer 160, There may be a shape of the convex portion 162 in which the path of light emitted from the light source 142 is different and the light extraction efficiency is not improved at all.
Figure 5 shows various shapes of convex portions of an overcoat layer having the same or similar aspect ratio (A / R).
5, if the shape of the convex portion 162 of the overcoat layer 160 is triangular as shown in FIG. 5, the half height width F of the convex portion 162 of the overcoat layer 160 may have a diameter (D / 2). At this time, the slopes S of the lower surface of the convex portion 162 of the overcoat layer 160 are all the same.
5, the convex portion 162 of the overcoat layer 160 included in the OLED display 100 may have a half height F of less than a radius D / 2 . The half height width F of the convex portion 162 of the overcoat layer 160 is larger than the radius D / 2 because the side surface of the convex portion 162 has a fat shape compared with the triangular shape, The path may increase and the external light extraction efficiency may be lowered. In contrast, as described above, the half-height width F of the convex portion 162 of the overcoat layer 160 is smaller than the radius D / 2 because the side surface of the convex portion 162 has a slender shape The light path in the lateral direction is reduced and the external light extraction efficiency can be improved. The convex portion 162 of the overcoat layer 160 included in the organic light emitting display 100 according to an exemplary embodiment may have a ratio of the half height width F to the radius D / 2 of the convex portion 162 , 0.1 or less.
6 is a graph showing current efficiency enhancement (%) according to the half height width of each of the organic light emitting display devices in which the half height width F of the convex portion 162 of the overcoat layer 160 has various values. Or enhancement of current efficiency (%)). At this time, the larger the current efficiency rising rate, the better the luminous efficiency.
For example, in the OLED display 100 in which the convex portion 162 of the overcoat layer 160 has a diameter D of 4.5 μm and a height H of 1.7 μm and an aspect ratio A / R of 0.76, It was confirmed that the current efficiency increase rate was better than that in the case where the width (F) was less than 2.0 μm as compared with the case where the half height width (F) was 2.0 or more. Rather, if the half-height width F of the convex portion 162 of the overcoat layer 160 has a value of 2.0um or more, the tendency of the current efficiency increasing rate to be lowered (the rate of increase is negative) can be confirmed.
When the half height width F is equal to or greater than 2.0 袖 m even if the aspect ratio A / R of the convex portion 162 of the overcoat layer 160 has an optimum value, (For example, 42 degrees) at which the angle of the proceeding light must be trapped between the substrate 110 and the organic light emitting layer 142. As a result, the rate of current efficiency rise tends to be rather lowered, and the luminous efficiency is lowered.
On the other hand, the half height width aspect ratio F_A / R of the convex portion 162 may be larger than the aspect ratio A / R. The half height width aspect ratio F_A / R of the convex portion 162 means the height H with respect to the half height width F of the convex portion 162. The half height width aspect ratio to the aspect ratio of the convex portion 162 may be larger than 1.0. As described above, for example, when the aspect ratio A / R of the convex portion 162 is 0.7 or more and 0.8 or less, for example, the half height width aspect ratio F_A / R of the convex portion 162 may be more than 0.8 and less than 2.0.
The convex portion 162 of the overcoat layer 160 may have various shapes even if the half height width F is less than the radius D / 2 and the half height width F is the same.
For example, when the half-height width F of the convex portion 162 of the overcoat layer 160 is smaller than the radius D / 2, the inclination of the convex portion 162 of the overcoat layer 160, (The shape of f1 in Fig. 5) that continuously increases from the floor to the top. In the same case, the inclination S of the convex portion 162 of the overcoat layer 160 gradually decreases from the maximum inclination Smax to the minimum inclination Smin. The shape gradually increases from the minimum inclination Smin F2 < / RTI > shape). Also, in the same case, the slope S of the convex portion 162 of the overcoat layer 160 gradually increases to reach the maximum slope Smax and then decreases again (f3 in Fig. 5).
The slope of the organic light-emitting layer 142 between the convex portion 162 of the overcoat layer 160 and the first connection portion 161 may be lowered due to the characteristics of the deposition process of the organic light-emitting layer 142, Is the largest, and the amount of light emitted by the organic light emitting layer 142 is the largest at the maximum slope Smax. Therefore, when the convex portion 162 has the shape of f1 or the shape of f2, the position with the largest light emission amount is located at the bottom or the top of the convex portion 162. [ In this case, the light emitted from the organic light emitting layer 142 is totally reflected within the first electrode 141 and the organic light emitting layer 142 and is trapped by the inserted micro-lens array structure at an angle smaller than the total reflection critical angle, The effect of increasing the external luminous efficiency is inevitably reduced.
In other words, in the organic light emitting diode display 100 according to the embodiment, when the convex portion 162 of the overcoat layer 160 has a shape that the inclination at the bottom increases and then decreases at the maximum inclination (f3 in FIG. 5) The light emitted from the light source 142 proceeds at an angle smaller than the total reflection critical angle, and the external light emission efficiency is increased through multiple reflection, so that the maximum external light extraction efficiency can be obtained.
On the other hand, the overcoat layer 161 can increase the external light extraction efficiency when the first connecting portion connecting the convex portions has a gentle inclination. The separation distance G (Gap) at the bottom of the convex portion 162 is zero as shown in Fig. 3C. If G is greater than 0, the effective light emitting area decreases because the gap between adjacent two convex portions 162 exists, so that the light emitting efficiency can be reduced by the area of the separation distance G. [
7A and 7B are diagrams showing optical paths along the maximum inclination of convex portions of the overcoat layer.
As shown in FIGS. 7A and 7B, even when the convex portion 162 of the overcoat layer 160 having the shape (shape of f3 in FIG. 5) decreases at the maximum slope Smax while the slope increases, Therefore, it can have various shapes.
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7A and 7B, the maximum inclination Smax of the convex portion 162 of the overcoat layer 160 may be set to a high angle of more than 60 degrees, for example, 70 degrees (FIG. 7A) or 65 degrees (FIG. 7B), the traveling angle of the light starting to proceed from the effective light emitting region is more than 42 degrees, which is the total reflection critical angle, so that the light emitting efficiency can not be increased again.
Therefore, the shape of the convex portion 162 of the overcoat layer 160 shown in FIGS. 4B to 4D is such that when the maximum slope Smax of the convex portion 162 is 40 to 60 degrees (for example, 50 degrees) The light emitted from the organic light emitting layer 142 is not trapped in the organic light emitting diode 140 when the traveling angle of the light starts to progress from the effective light emitting area.
8 is a graph showing current efficiency enhancement (%) according to the maximum slope Smax of each OLED display device having a maximum slope Smax of the convex portion 162 of the overcoat layer 160, ) Or enhancement of current efficiency (%)).
8, when the maximum slope Smax of the convex portion 162 of the overcoat layer 160 is less than 40 degrees, the light advancing angle in the effective luminescent region is larger than the flat organic light emitting element of the overcoat layer 160 It is confirmed that there is almost no improvement in efficiency. When the maximum inclination Smax of the convex portion 162 of the overcoat layer 160 is more than 60 degrees, the light propagation angle is larger than the total reflection angle of the air layer outside the substrate 110 and the substrate 110 shown in FIG. The amount of light confined in the organic light emitting diode 140 increases greatly and the efficiency of the organic light emitting diode of the overcoat layer 160 is lower than that of the organic light emitting diode of the overcoat layer 160.
As described above, the shape of the convex portion 162 of the overcoat layer 160 shown in FIGS. 4B to 4D is such that when the maximum slope Smax of the convex portion 162 is 40 to 60 degrees, The light emitted from the organic light emitting layer 142 is not trapped in the organic light emitting diode 140, so that the light emitting efficiency can be increased.
4B to 4D show the maximum slope Smax in the first region C to the third region A when the height H of the convex portion 162 of the overcoat layer 160 is taken as a reference, Of the overcoat layer 160 are located.
Height half width ratio Rm with respect to the aspect ratio of the convex portion 162 is the ratio of the half height width aspect ratio F_A / R to the aspect ratio A / R and the region having the sharpest maximum slope Smax is the first region (C) to the third region (A). When the half-height width aspect ratio Rm with respect to the aspect ratio of the convex portion 162 is less than 1.0, the region having the maximum slope Smax is the first region C. The region having the maximum slope Smax when the half height width aspect ratio Rm is 1.0 with respect to the aspect ratio of the convex portion 162 is the second region B. [ The area having the maximum slope Smax when the half height width aspect ratio Rm of the convex portion 162 with respect to the aspect ratio is more than 1.0 is the third region A. [
The optical path of the light emitted from the organic light emitting layer 142 shown in FIGS. 4B to 4D is the same as that of the first to third It can be seen that the front emission efficiency is the best when the first region A is located in the third region A adjacent to the normal region. As described above, when the organic light emitting diode 140 is driven, the electric field is locally concentrated in the efficient light emitting region Y and a main current path is formed to cause the main light emission, whereas the convex portion 162 of the overcoat layer 160 The light emission efficiency can be lowered as the maximum slope is located in the first region C and the second region B. In this case,
The light extraction efficiency or the light emitting efficiency according to the shape of the convex portion 162 when the overcoat layer 160 includes the convex portion 162 has been described. Hereinafter, even when the overcoat layer 160 includes recesses, external light extraction efficiency or light emission efficiency depending on the shape of the recesses, like the protrusions 162, will be described with reference to FIG.
9 is a cross-sectional view illustrating an organic light emitting display including an overcoat layer including a plurality of recesses according to another embodiment.
Referring to FIG. 9, the OLED display 200 according to another embodiment of the present invention includes a plurality of recesses 264 in the overcoat layer 260, as compared with the OLED display 100 of FIGS. 1 and 2B. And the other constitutions are substantially the same, and redundant explanations are omitted. The elements of the organic light emitting display 200, which are not shown in FIG. 9, may be the same as the elements of the organic light emitting display 100 according to the embodiments described with reference to FIGS. 1 and 2B.
The overcoat layer 260 includes a plurality of recesses 264 formed to overlap the color filter 250 and a second connection portion 263 connecting the recesses 264 adjacent to each other. In other words, the overcoat layer 260 includes a plurality of concave portions 264 arranged to overlap with the openings 136a of the bank layer 136 shown in FIG. 1 and a plurality of second connection portions 264 connecting the concave portions 264, (263).
A first electrode (241) is disposed on the overcoat layer (260). The organic light emitting layer 242 and the second electrode 243 are disposed on the first electrode 241. The first electrode 241, the organic light emitting layer 242, and the second electrode 243 constitute the organic light emitting diode 240.
The first electrode 241, the organic light emitting layer 242 and the second electrode 243 may be disposed along the top surface of the overcoat layer 260 to have a shape conforming to the morphology of the overcoat layer 260.
As described above with reference to FIGS. 3A and 3B, the half-height width F of the convex portion 162 of the overcoat layer 160 is smaller than the radius D / 2, The half-height width F of the protrusion 264 may be smaller than the radius D / 2. At this time, the ratio of the half height width F to the radius D / 2 of the concave portion 264 may be 0.1 or less.
As described with reference to FIGS. 3A and 3B, the half height width aspect ratio F_A / R of the convex portion of the overcoat layer 160 is larger than the aspect ratio A / R, 264 may have an aspect ratio (F_A / R) greater than an aspect ratio (A / R). At this time, the half-height width aspect ratio F_A / R with respect to the aspect ratio A / R of the concave portion 264 may be larger than 1.0.
At this time, the concave portion 264 may have a hexagonal shape with a diameter of 1 to 5 mu m and a height of 1 to 4 mu m.
The convex portion 162 of the overcoat layer 160 has a concave portion 264 of the overcoat layer 260 as shown in FIG. 4B to FIG. 5, ) May have a shape in which the slope at the bottom increases and gradually decreases at the maximum slope.
The maximum slope of the concave portion 264 of the overcoat layer 260 is set to 40 占 퐉 as in the case where the maximum slope of the convex portion 162 of the overcoat layer 160 is 40 占 to 60 占 as described with reference to Figs. To 60 degrees.
When the overcoat layer 260 includes the concave portion 264, the concave portion 264 is formed in the same manner as the convex portion 162 of the overcoat layer 160 of the organic light emitting diode display 100 described with reference to FIG. The characteristics depending on the shape of the concave portion 264 and the second connection portion 263 according to the omitted parameters are the same as those of the convex portion 162 and the first connection portion 261).
10 is a schematic system configuration diagram of an organic light emitting display according to the present embodiments.
10, a plurality of data lines DL and a plurality of gate lines GL are arranged in the organic light emitting diode display 300 according to the present embodiment, and a plurality of subpixels SP are arranged in a matrix type An organic light emitting diode (OLED) display panel 310 disposed on the organic light emitting display panel 310, a plurality of data lines driven by a plurality of data lines, a driving data driver 320, and a plurality of gate lines sequentially supplying scan signals, A gate driver 330 for sequentially driving gate lines, a controller 340 for controlling the data driver 320 and the gate driver 330, and the like.
Each of the plurality of pixels arranged in the organic light emitting diode display panel 310 includes the thin film transistor and the organic light emitting element described with reference to FIG.
According to the embodiments described above, the organic light emitting display device has an effect of improving the external luminous efficiency and lowering the power consumption.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. , Separation, substitution, and alteration of the invention will be apparent to those skilled in the art. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.
