KR102498271B1 - Organic light emitting display device - Google Patents

Abstract

In this embodiment, an overcoating layer disposed on a substrate and including a convex portion or a concave portion disposed to correspond to each pixel region, a first electrode disposed on the overcoating layer, an organic light emitting layer disposed on the first electrode, and an organic light emitting layer The present invention relates to an organic light emitting display device including a second electrode disposed thereon, and having a shape in which a slope of the convex portion or the concave portion increases from a bottom to a top and then decreases.

Description

Organic light emitting display {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present embodiments relate to organic light emitting display devices that display images.

Recently, an organic light emitting display device that has been in the limelight as a display device uses an organic light emitting diode (OLED) that emits light by itself, so it has a fast response speed, contrast ratio, luminous efficiency, luminance, and viewing angle. There are advantages.

Light emitted from the organic light emitting layer of the organic light emitting display device passes through various elements of the organic light emitting display device and comes out of the organic light emitting display device. However, among the light emitted from the organic light emitting layer, light that does not come out of the organic light emitting display device and is trapped inside the organic light emitting display device exists, and light extraction efficiency of the organic light emitting display device becomes a problem. In order to improve the light extraction efficiency of the organic light emitting display device, a method of attaching a micro lens array (MLA) to the outside of a substrate of the organic light emitting display device is used.

An object of the present embodiments is to provide an organic light emitting display device that improves external light emitting efficiency and lowers power consumption.

An embodiment includes an overcoating layer disposed on a substrate, a first electrode disposed on the overcoating layer, an organic light emitting layer disposed on the first electrode and including a convex or concave curve, and a second electrode disposed on the organic light emitting layer. An organic light emitting display device including the above may be provided.

In the organic light emitting layer, a region having the shortest thickness may be positioned between the bottom and top of the curve.

According to the present embodiments as described above, it is possible to provide an organic light emitting display device capable of improving external light emitting efficiency and reducing power consumption.

1 is a cross-sectional view of an organic light emitting display device according to an exemplary embodiment.
FIG. 2A is an enlarged cross-sectional view of region X of FIG. 1 .
FIG. 2B is a partial plan view of an overcoating layer, a first electrode, and a pattern layer in region X of FIG. 1 .
FIG. 3A conceptually shows variables that determine the shape of the convex portion 162 of the overcoating layer 160 .
3B illustrates variables that determine the shape of a convex portion of an overcoating layer in an organic light emitting display device according to an exemplary embodiment.
3C is a diagram for explaining the concept of a gap G at the bottom of the convex portion of the overcoat layer.
4A to 4D are cross-sectional views comparing shapes of convex portions of the overcoating layer 160 having the same aspect ratio.
5 shows various shapes of convex portions of the overcoating layer having the same or similar aspect ratio (A/R).
FIG. 6 shows the current efficiency enhancement (%) according to the half-height width of each organic light emitting display device in which the half-height width (F) of the convex portion 162 of the overcoating layer 160 has various values. Or, it is a graph showing the relationship between enhancement of current efficiency (%)).
7A and 7B are diagrams illustrating a light path according to a maximum slope of a convex portion of an overcoating layer.
8 shows current efficiency enhancement (%) according to the maximum slope (Smax) of organic light emitting display devices in which the maximum slope (Smax) of the convex portion 162 of the overcoating layer 160 has various values. ) or enhancement of current efficiency (%)).
9 is a cross-sectional view illustrating an organic light emitting display device including an overcoating layer including a plurality of concave portions according to another exemplary embodiment.
10 is a schematic system configuration diagram of an organic light emitting display device according to the present embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

Also, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present invention. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

1 is a cross-sectional view of an organic light emitting display device according to an exemplary embodiment. FIG. 2 is an enlarged cross-sectional view of region X of FIG. 1 . FIG. 2B is a partial plan view of an overcoating layer, a first electrode, and a pattern layer in region X of FIG. 1 .

1 and 2 , an organic light emitting display device 100 according to an exemplary embodiment includes a substrate 110, a thin film transistor 120, a color filter 150, an overcoating layer 160, and a pattern layer 337. and an organic light emitting device 140 .

The organic light emitting display device 100 shown in FIGS. 1 and 2A is a bottom emission type organic light emitting display device. However, the organic light emitting display device 100 according to an exemplary embodiment may be a top emission type organic light emitting display device in which the color filter 150 is positioned 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 the substrate 110 .

Specifically, 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. ) is disposed, the active layer 122 is disposed on the gate insulating layer 131, an etch stopper 132 is disposed on the active layer 122, and the active layer 122 and the etch star A source electrode 123 and a drain electrode 124 are disposed on the fur 132 . The source electrode 123 and the drain electrode 124 are electrically connected to the active layer 122 in a manner in contact with the active layer 122 and are disposed on a portion of the etch stopper 132 . The etch stopper 132 may not be disposed.

In this specification, only the driving thin film transistor among various thin film transistors that may be included in the organic light emitting display device 100 is illustrated for convenience of description. In addition, in this specification, the thin film transistor 120 has an inverted staggered structure in which the gate electrode 121 is located on opposite sides of the source electrode 123 and the drain electrode 124 with respect to the active layer 122. ) structure or a bottom gate structure, but a coplanar structure or top gate in which the gate electrode 121 is located on the same side as the source electrode 123 and the drain electrode 124 based on the active layer 122 Structured thin film transistors may 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 .

In FIG. 2A , the passivation layer 133 is illustrated as planarizing the upper portion of the thin film transistor 120 , but the passivation layer 133 does not planarize the upper portion of the thin film transistor 120 and may be disposed along the surface shapes of elements located below. may be

The color filter 150 is for color-converting light emitted from the organic emission layer 142 and may be one of a red color filter, a green color filter, and a blue color filter.

The color filter 150 is disposed at a position corresponding to the emission area on the passivation layer 133 . Here, the light emitting area means an area 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 area. This means that the color filter 150 is disposed to prevent blurring and ghosting from occurring by mixing light emitted from the light emitting regions.

For example, the color filter 150 may be disposed to overlap the light emitting area and may have a size smaller than or equal to the light emitting area. However, the arrangement position and size of the color filter 150 are not only the size and position of the light emitting area, but also the distance between the color filter 150 and the first electrode 141, and the distance between the color filter 150 and the overcoating layer 160. It may be determined by various factors such as the distance between the convex portions 162 and the distance between light emitting regions.

An overcoat layer 160 is disposed on the color filters 150 and 133. Although the passivation layer 133 is illustrated as being included in the organic light emitting display device 100 in FIG. 2A , the overcoating layer 160 may be disposed directly on the thin film transistor 120 without using the passivation layer 133 . there is. In FIG. 2A , the color filter 150 is illustrated as being disposed on the passivation layer 133, but is not limited thereto, and the color filter 150 is disposed at an arbitrary position between the overcoating layer 160 and the substrate 110. It can be.

The overcoating layer 160 includes a plurality of convex portions 162 disposed to overlap the color filter 150 and a first connection 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 . The first connecting portion 161 is a low portion between adjacent convex portions 162 . The overcoating layer 160 functions as a planarization layer in areas where the plurality of convex portions 162 are not disposed.

As shown in FIG. 2B, each of the plurality of convex portions 162 and the first connection portion 161 may have a hexagonal shape as a whole on a plane, but is not limited thereto, and may have various shapes such as a hemispherical shape, a semi-ellipsoidal shape, or a square shape as a whole. can The plurality of convex portions 162 may be arranged in a hexagonal honeycomb structure on a plane. In other words, one convex portion 162 of a hexagonal shape and another convex portion 162 adjacent to each other may be disposed in a hexagonal honeycomb structure integrally formed by sharing one side.

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 are disposed on the overcoating layer 160 . At this time, although not shown, diffusion of outgassing from the overcoating layer 160 to the organic light emitting device 140 is prevented while having a shape that follows the morphology of the convex portion 162 of the overcoating 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 overcoating layer 160 and the first electrode 141 .

Specifically, the first electrode 141 for supplying either electrons or holes to the organic light emitting layer 142 is disposed on the overcoating layer 160 . The first electrode 141 may be an anode, a pixel electrode, or an anode in a normal OLED, and 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 overcoating layer 160 and the passivation layer 133 . In this specification, it is assumed that the thin film transistor 120 is an N-type thin film transistor, and the first electrode 141 is connected to the source electrode 123, but the thin film transistor 120 is a P-type thin film transistor. In the case of , 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 through a conductive material.

The first electrode 141 is disposed in a shape following the morphology of the surface of the overcoating layer 160 . Accordingly, the first electrode 141 has a convex morphology at the convex portion 162 of the overcoating layer 160 .

A bank layer 136 including an opening 136a exposing the first electrode 141 is disposed on the overcoat layer 160 and the first electrode 141 . The bank layer 136 serves to divide adjacent pixel (or sub-pixel) areas, and may be disposed between adjacent pixel (or sub-pixel) areas. The convex portion 162 of the overcoating layer 160 and the first connection portion 161 are disposed to overlap the opening 136a of the bank layer 136 . As described above, since the convex portion 162 of the overcoating layer 160 and the first connection portion 161 are disposed to overlap the color filter 150, the convex portion 162 of the overcoating layer 160 and the first connection portion ( 161 overlaps the color filter 150 at the bottom and the opening 136a of the bank layer 136 at the top.

An organic light emitting layer 142 is disposed on the first electrode 141 , and a second electrode 143 for supplying either electrons or holes to the organic light emitting layer 142 is disposed on the organic light emitting layer 142 . The organic light emitting layer 142 is disposed 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 may include 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 becomes white when mixed with blue light. The second organic light-emitting layer may be, for example, an organic light-emitting layer that emits yellow-green light. Meanwhile, the organic light emitting layer 142 may include only an organic light emitting layer emitting one of blue light, red light, and green light. In this case, 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 OLED, and may be an anode, a common electrode, or an anode in an inverted OLED.

Referring to FIG. 2A , the thickness of the organic light emitting layer 142 between the convex portion 162 of the overcoating layer 160 and the first connection portion 161 is the top of the convex portion 162 of the overcoating layer 160 or the first connection portion. 161 may be thinner than the thickness of the organic light emitting layer 142 . In particular, 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 the largest between the convex portion 162 of the overcoating layer 160 and the first connection portion 161.

For example, when the organic emission layer 142 is formed by deposition, the organic emission layer 142 deposited in a direction perpendicular to the substrate 110 may have a shape following the morphology of the overcoating layer 160 . Due to the characteristics of the deposition process, the actual thickness d1 of the organic light emitting layer 142 between the first electrode 141 and the second electrode 142 becomes the thinnest at the 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 are the thickest at the position where the slope of the organic light emitting layer 142 is the smallest, that is, the bottom or the top. In terms of the amount of light emitted from the organic light emitting layer 142 according to the thickness (d1, d2, d3, etc.) of the organic light emitting layer 142, the organic light emitting layer ( The amount of light emitted per unit area of 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 . In particular, the light emission amount of the organic light emitting layer 142 may be greatest at a position where the slope of the organic light emitting layer 142 is greatest between the convex part 162 of the overcoating layer 160 and the first connection part 161.

The organic light emitting layer 142 and the second electrode 143 are the first electrode 141 having a shape following the morphology of the surface of the overcoating layer 160, the organic light emitting layer 142 and the second electrode 143 are It follows the morphology of the upper surface of the first electrode 141. As a result, the shape of the organic light emitting device 140 may be implemented using the convex portion 162 of the overcoating layer 160 .

When the organic light emitting device 140 has a micro lens array structure for improving external light extraction efficiency, the convex portion 162 of the overcoating layer 160 is shown in FIG. ) results in a convex curve. At this time, as the gradient increases, the shortest thickness d1, which is the thickness of the shortest distance in the organic light emitting layer 142 between the first electrode 141 and the second electrode 143, becomes thinner, and the efficiency light emitting region (Y ), that is, a region between the convex portion 162 of the overcoating layer 160 and the first connection portion 161 occurs. When the organic light emitting device 140 is driven, an electric field is locally concentrated in this efficient light emitting area and a main current path is formed, so that main light emission occurs. ), almost no light is extracted. In this inefficient light emitting region Z, almost no light is extracted even though power is consumed, and thus external light extraction efficiency is lowered.

The organic light emitting display device 100 according to an exemplary embodiment may include an overcoating layer 160 having a convex micro lens array pattern on the color filter 150 . The light emitted from the organic light emitting layer 142 is totally reflected inside the first electrode 141 and the organic light emitting layer 142, and propagates at an angle smaller than the critical angle of total reflection by the micro lens array structure in which the confined light is inserted. The luminous efficiency can be increased.

At this time, the propagation angle of the light emitted from the organic light emitting layer 142 is changed by the micro lens array pattern, and the propagation angle of the light may be clearly different even by the minute difference in the shape of the micro lens array.

The shape of the convex portion 162 of the overcoating layer 160 is formed through a process such as photolithography, and by adjusting the heat treatment process performed at this time, the morphology of the convex portion 162 of the overcoating layer 160 can be adjusted.

More specifically, it is as follows. In order to form the convex portion 162 of the overcoating layer 160, photoresist is applied and patterned into a convex shape through a photolithography process, followed by heat treatment. In this case, the shape of the convex portion 162 of the overcoating layer 160 can be formed only when the heat treatment is performed step by step over two stages, rather than being performed at once. For example, an intermediate heat treatment at about 100 °C or more and 130 °C or less should be performed first before performing the final heat treatment at about 200 °C or more and 250 °C or less.

At this time, the time for performing the intermediate heat treatment is related to the morphology of the convex portion 162 of the overcoating layer 160. As the time for performing the intermediate heat treatment increases, the shape of the convex portion 162 of the finally formed overcoating layer 160 increases. Extremely, when only the final heat treatment is performed without the time for performing the intermediate heat treatment, the shape of the convex portion 162 of the overcoating layer 160 is lost and the overcoating layer 160 is flattened.

Using this tendency, various organic light emitting display devices having different morphologies of the convex portions 162 of the overcoating layer 160 were manufactured. Using this, when the convex portion 162 of the overcoating layer 160 has a certain morphology, that is, when the convex portion 162 of the overcoating layer 160 has a specific aspect ratio, the organic light emitting diode 140 emits maximum light. An experiment was conducted to see if it could operate with efficiency.

The organic light emitting display device 100 according to an exemplary embodiment is totally reflected inside the organic light emitting device 140 through a light path that changes according to the shape of the convex portion 162 of the overcoating layer 160 to improve external light extraction efficiency. It is to allow the trapped light to be extracted to the outside.

Since the light path change according to the shape of the convex portion 162 of the overcoating layer 160 inserted to improve the external light extraction efficiency is a major factor in improving the light extraction efficiency, the overcoating layer 160 defined below as a variable determining the shape ) of the convex part 162 (D (Diameter)), height (H (Height)), aspect ratio (A / R (Aspect Ratio)), half height width (F (Full Width Half Max)), half height Width aspect ratio (F_A/R (=H/F)), slope (S (Slope)), distance from the bottom of the convex part 162 (G (Gap)), half-height width aspect ratio (Rm (Ratio of MLA=(F_A/R)/(A/R))) and the like.

FIG. 3A conceptually shows variables that determine the shape of the convex portion 162 of the overcoating layer 160 . 3B illustrates variables that determine the shape of a convex portion of an overcoating layer in an organic light emitting display device according to an exemplary embodiment. 3C is a diagram for explaining the concept of a gap G at the bottom of the convex portion of the overcoat layer.

3A and 3B, the diameter (D) of the convex part 162 of the overcoating layer 160 means the length of the convex part 161 at the bottom position, and the height (H) is the convex part 162 It means the length from the top of the to the bottom of the first connection portion 161. As shown in FIG. 3A, the half-height width F means the length of the convex part 162 at half the height of the convex part 162. 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 having a diameter D of 1 μm to 5 μm and a height H of 1 μm to 4 μm.

When the aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 has a value of about 0.2 or more and less than or equal to 0.8, the aspect ratio (A/R) of the convex portion 161A of the overcoating layer 160 is It can be seen that the current efficiency increase rate is more excellent than when the value exceeds 0.8. Rather, when the aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 has a value greater than about 0.8, the rate of increase in current efficiency tends to decrease. In particular, when the aspect ratio of the convex portion 162 of the overcoating layer 160 has a value between about 0.4 and 0.7, it can be seen that the rate of increase in current efficiency is greatest.

Accordingly, the aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 of the surface on which the organic light emitting element 140 is disposed in the illustrated organic light emitting display device 100 according to an exemplary embodiment is about 0.2 or more. It may be the top surface of the overcoating layer 160 having a value of about 0.8 or less. Alternatively, in the illustrated organic light emitting display device 100 according to an embodiment of the present invention, the aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 is It may have the same shape as the upper surface of the second passivation layer (not shown) that follows the morphology of the overcoating layer 160 having a value between about 0.2 and about 0.8. That is, the overcoating layer 160 or the second passivation layer (not shown) at this time is a gentle non-flat surface having an aspect ratio (A/R) of about 0.2 or more and about 0.8 or less, and thereby organic light emitting. The device 140 is formed on a gentle non-flat screen having an aspect ratio of about 0.2 or more and about 0.8 or less, and the anode 141, the organic light emitting layer 142, and the cathode 143 have a morphology of the gentle non-flat screen. has a shape that follows

In summary, in forming the convex portion 162 of the overcoating layer 160, the intermediate heat treatment process must be carried out, but by making it somewhat shorter, the first connection portion 161 of the convex portion 162 of the overcoating layer 160 It can be formed to have a gentle slope. According to this method, when the overcoating layer 160 is formed such that the aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 has a value of 0.2 or more and 0.8 or less, as shown in FIG. 1, the overcoating layer The organic light emitting element 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 surface 160 .

When only the aspect ratio (A/R) is applied as a variable defining the shape of the convex portion 162 of the overcoating layer 160, the aspect ratio (A/R) is the same and is defined only by the diameter (D) and height (H). Even if the ratio is the same, the shape of the convex part 162 of the overcoating layer 160 changes significantly when the values defined by other variables such as the width of the half height (F) or the distance between the convex parts (G) are changed.

4A to 4D are cross-sectional views comparing shapes of convex portions of the overcoating layer 160 having the same aspect ratio.

FIG. 4A illustrates positions of first to third regions C, B, and A included in each division when the convex portion 162 of the overcoating layer 160 is divided into thirds based on the height.

4B to 4D are convex portions of the overcoating layer 160 having the same or similar aspect ratio (A/R) because the diameter (D) and height (H) of the convex portion 162 of the overcoating layer 160 are the same or similar. Sections of (162). The aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 shown in FIGS. 4B to 4D is about 0.6, and as described above, the convex portion 162 of the overcoating layer 160 has an excellent current efficiency increase rate. It is included in the range of 0.2 or more and 0.8 or less of

FIG. 4B shows the overcoating layer 160 where the maximum slope Smax is located in the first region C when the convex portion 162 of the overcoating layer 160 is divided into thirds based on the height H of the overcoating layer 160. A convex portion 162 is shown. At this time, the slope S of the convex portion 162 means an angle between a tangential line of the lower surface of the convex portion 162 and a horizontal plane, as shown in FIG. 4A. At this time, the maximum slope Smax means a slope at which the angle between the tangent of the lower surface of the convex portion 162 and the horizontal plane is the maximum.

FIG. 4C shows the convex portion 162 of the overcoating 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 overcoating layer 160 is divided into thirds. ) is shown.

4D, the convex portion 162 of the overcoating layer 160 has the maximum slope Smax located in the third area A when the height H of the convex portion 162 of the overcoating layer 160 is divided into thirds. ) is shown.

Although the aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 shown in FIGS. 4B to 4D is the same or similar, the organic light emitting layer is different according to the shape of the convex portion 162 of the overcoating layer 160. There may be a shape of the convex portion 162 in which a path of light emitted from 142 is different and the light extraction efficiency is not improved at all.

5 shows various shapes of convex portions of the overcoating layer having the same or similar aspect ratio (A/R).

Referring to FIG. 5, if the convex portion 162 of the overcoating layer 160 has a triangular shape as shown in FIG. 5, the half-height width F of the convex portion 162 of the overcoating layer 160 is the diameter is half (D/2) of At this time, the slopes S of the lower surfaces of the convex portions 162 of the overcoating layer 160 are all the same.

Referring to FIG. 5 , the convex portion 162 of the overcoating layer 160 included in the organic light emitting display device 100 according to an exemplary embodiment may have a half-height width (F) smaller than a radius (D/2). . The fact that the half-height width (F) of the convex portion 162 of the overcoating layer 160 is larger than the radius (D/2) means that the side surface of the convex portion 162 has a thicker shape compared to the triangular shape, so that light in the lateral direction is reduced. An increase in the path may reduce external light extraction efficiency. Conversely, as described above, when the half-height width (F) of the convex portion 162 of the overcoating layer 160 is smaller than the radius (D/2), the side surface of the convex portion 162 has a slender shape compared to a triangular shape. Since the light path in the lateral direction is reduced, the external light extraction efficiency can be improved. In this case, the ratio of the half-height width (F) to the radius (D/2) of the convex portion 162 of the overcoating layer 160 included in the organic light emitting display device 100 according to an exemplary embodiment is , may be as small as 0.1 or less.

FIG. 6 shows the current efficiency enhancement (%) according to the half-height width of each organic light emitting display device in which the half-height width (F) of the convex portion 162 of the overcoating layer 160 has various values. Or, it is a graph showing the relationship between enhancement of current efficiency (%)). At this time, it means that the higher the current efficiency increase rate, the better the luminous efficiency.

For example, in the organic light emitting display device 100 in which the diameter (D) of the convex portion 162 of the overcoating layer 160 is 4.5 μm, the height (H) is 1.7 μm, and the aspect ratio (A/R) is 0.76, the half-height It was confirmed that the case where the width (F) was less than 2.0um had a higher current efficiency increase rate than the case where the half-height width (F) was 2.0 or more. Rather, when the half-height width (F) of the convex portion 162 of the overcoating layer 160 has a value of 2.0 μm or more, the current efficiency increase rate tends to decrease (the increase rate has a negative value).

In summary, even in a structure in which the aspect ratio (A/R) of the convex portion 162 of the overcoating layer 160 has an optimal value, when the half-height width (F) has a value of 2.0 μm or more, the inside of the organic light emitting device 140 The angle of propagating light becomes greater than the critical angle of total reflection (for example, 42 degrees) that cannot but be confined between the substrate 110 and the organic light emitting layer 142 . As a result, it can be confirmed that the rate of increase in current efficiency tends to decrease, thereby reducing the luminous efficiency.

Meanwhile, the half-height-width aspect ratio (F_A/R) of the convex portion 162 may be greater than the aspect ratio (A/R). At this time, the half-height-width aspect ratio (F_A/R) of the convex portion 162 means the height (H) of the convex portion 162 to the half-height width (F). The aspect ratio of the half-height and width to the aspect ratio of the convex portion 162 may be greater than 1.0. As described above, when the aspect ratio (A/R) of the convex portion 162 is greater than or equal to 0.7 and less than or equal to 0.8, the half-height-width aspect ratio (F_A/R) of the convex portion 162 may be greater than 0.8 and less than 2.0.

As shown in FIG. 5 , the convex portion 162 of the overcoating layer 160 may have various shapes even if the half-height width F is smaller 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 overcoating layer 160 is smaller than the radius (D/2), the slope of the convex portion 162 of the overcoating layer 160 relative to the left side is (S) may have a continuously increasing shape from the bottom to the top (f1 shape in FIG. 5). Also, in the same case, the slope S of the convex portion 162 of the overcoating layer 160 gradually decreases from the maximum slope Smax to the minimum slope Smin and gradually increases again from the minimum slope Smin (FIG. 5 of f2 shape). Also, in the same case, the slope S of the convex portion 162 of the overcoating layer 160 may gradually increase to reach the maximum slope Smax and then gradually decrease again (f3 in FIG. 5).

As described above with reference to FIG. 2A , due to the nature of the deposition process of the organic light emitting layer 142 , the slope of the organic light emitting layer 142 between the convex portion 162 of the overcoating layer 160 and the first connection portion 161 ) is the largest, the light emission amount of the organic light emitting layer 142 is greatest at the maximum slope (Smax). Therefore, when the convex portion 162 has the shape of f1 or f2, the position where the light emission is greatest is located at the bottom or top of the convex portion 162. In this case, the light emitted from the organic light emitting layer 142 is totally reflected inside the first electrode 141 and the organic light emitting layer 142, and propagates at an angle smaller than the critical angle of total reflection by the micro lens array structure in which the confined light is inserted and multiple reflections Through this, the effect of increasing the external luminous efficiency is inevitably reduced.

In other words, in the organic light emitting display device 100 according to an exemplary embodiment, when the convex portion 162 of the overcoating layer 160 has a shape in which the slope increases from the bottom and decreases at the maximum slope (f3 in FIG. 5), the organic light emitting layer ( 142), the emitted light travels at an angle smaller than the critical angle of total reflection, and the external light emitting efficiency is increased through multiple reflections, so that maximum external light extraction efficiency can be obtained.

Meanwhile, in the overcoating layer 161 , external light extraction efficiency may increase when the first connecting portion connecting each of the convex portions has a gentle slope. As shown in FIG. 3C , the distance G (Gap) from the bottom of the convex portion 162 is zero. When G is greater than 0, it is because there is a gap between the two adjacent convex portions 162, and since the effective light emitting area is reduced, the luminous efficiency can be reduced by the area of the separation distance (G).

7A and 7B are diagrams illustrating a light path according to a maximum slope of a convex portion of an overcoating layer.

As shown in FIGS. 7A and 7B , even if the convex portion 162 of the overcoating layer 160 has a shape in which the slope increases and then decreases at the maximum slope Smax (f3 shape in FIG. 5), the angle of the maximum slope Therefore, it can have various shapes.

As shown in FIGS. 7A and 7B, the maximum inclination (Smax) in the shape of the convex portion 162 of the overcoating layer 160 is at a high angle exceeding 60 degrees, for example, 70 degrees (FIG. 7A) or 65 degrees. (FIG. 7B), when the light propagation angle starting from the effective light emitting region is 42 degrees or more, which is the critical angle of total reflection, it is eventually trapped inside the organic light emitting device 140 again, and the luminous efficiency may not be increased.

Therefore, the shape of the convex portion 162 of the overcoating layer 160 shown in FIGS. 4B to 4D is when the maximum inclination (Smax) of the convex portion 162 is 40 degrees to 60 degrees (for example, 50 degrees). When viewing a propagation angle of light starting from the effective light emitting region, the light emitted from the organic light emitting layer 142 is not confined to the inside of the organic light emitting device 140, and the light emitting efficiency may increase.

8 shows current efficiency enhancement (%) according to the maximum slope (Smax) of organic light emitting display devices in which the maximum slope (Smax) of the convex portion 162 of the overcoating layer 160 has various values. ) or enhancement of current efficiency (%)).

Referring to FIG. 8 , when the maximum slope (Smax) of the convex portion 162 of the overcoating layer 160 is less than 40 degrees, the light propagation angle in the effective light emitting region is significantly different from that of the flat organic light emitting device of the overcoating layer 160. Since there is no change, it was confirmed that there is little improvement in efficiency. In addition, when the maximum slope (Smax) of the convex portion 162 of the overcoating layer 160 exceeds 60 degrees, the light propagation angle is greater than the total reflection angle between the substrate 110 and the air layer outside the substrate 110 shown in FIG. As the organic light emitting device 140 is formed large, the amount of light trapped inside the organic light emitting device 140 greatly increases, resulting in lower efficiency than that of the flat organic light emitting device of the overcoating layer 160 .

As described above, the shape of the convex portion 162 of the overcoating layer 160 shown in FIGS. 4B to 4D proceeds from the effective light emitting area when the maximum slope (Smax) of the convex portion 162 is 40 to 60 degrees. When the starting angle of light is viewed, light emitted from the organic light emitting layer 142 is not confined within the organic light emitting device 140, so that light emitting efficiency may increase.

As described above, in FIGS. 4B to 4D , 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 overcoating layer 160 is divided into thirds. ) shows the convex portions 162 of the overcoating layer 160 where the

The half height width aspect ratio Rm 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 steepest maximum slope Smax is the first region. It can be said to be a variable that determines whether it exists in (C) to the third area (A). When the half-height-width aspect ratio Rm of the convex portion 162 to the aspect ratio is less than 1.0, the region having the maximum slope Smax is the first region C. When the aspect ratio (Rm) of the half-height width to the aspect ratio of the convex portion 162 is 1.0, the area having the maximum slope (Smax) is the second area (B). When the half-height-width aspect ratio Rm of the convex portion 162 is greater than 1.0, the area having the maximum slope Smax is the third area A.

4b to 4d, the maximum slope Smax of the convex portion 162 is the first to third thirds obtained by dividing the height H from the bottom when examining the light path of the light emitted from the organic light emitting layer 142 shown in FIGS. 4B to 4D. It can be seen that the front luminous efficiency is the best when located in the third region (A) adjacent to the top among the regions. As described above, when the organic light emitting device 140 is driven, an electric field is locally concentrated in the efficient light emitting region Y, and a main current path is formed, so that main light emission occurs, while the convex portion 162 of the overcoating layer 160 ), almost no light is extracted to the inefficient light emitting region Z, and the luminous efficiency may decrease as the maximum slope is located in the first region C and the second region B.

When the overcoating layer 160 includes the convex portion 162, light extraction efficiency or luminous efficiency according to the shape of the convex portion 162 has been described. Hereinafter, even when the overcoating layer 160 includes the concave portion, it will be described with reference to FIG. 9 that the same external light extraction efficiency or luminous efficiency according to the shape of the concave portion as the convex portion 162 is provided.

9 is a cross-sectional view illustrating an organic light emitting display device including an overcoating layer including a plurality of concave portions according to another exemplary embodiment.

Referring to FIG. 9 , the organic light emitting display device 200 according to another embodiment includes a plurality of concave portions 236 in the overcoating layer 260 compared to the organic light emitting display device 100 of FIGS. 1 to 2B . Only the configuration is different, and other configurations are substantially the same, so redundant description is omitted. Elements of the organic light emitting display device 200 not shown in FIG. 9 may be the same as elements of the organic light emitting display device 100 according to the exemplary embodiments described with reference to FIGS. 1 to 2B .

The overcoating layer 260 includes a plurality of concave portions 264 formed to overlap the color filter 250 and a second connection portion 263 connecting the concave portions 264 adjacent to each other. In other words, the overcoating layer 260 includes a plurality of concave portions 264 disposed to overlap the opening 136a of the bank layer 136 shown in FIG. 1 and a plurality of second connection portions connecting the concave portions 264, respectively. (263).

A first electrode 241 is disposed on the overcoating layer 260 . An organic emission layer 242 and a 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 device 240 .

The first electrode 241, the organic light emitting layer 242, and the second electrode 243 may be disposed along the shape of the upper surface of the overcoating layer 260 and may have a shape following the morphology of the overcoating layer 260.

As described with reference to FIGS. 3A and 3B , the concave portion of the overcoating layer 260 has the same half-height width (F) of the convex portion 162 of the overcoating layer 160 as being smaller than the radius (D/2). The half-height width (F) of (264) may be smaller than the radius (D/2). In this case, 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 concave portion of the overcoating layer 260 is equal to the fact that the half-height width F of the convex portion 162 of the overcoating layer 160 is smaller than the radius D/2. The half-height width (F) of (264) may be smaller than the radius (D/2). In this case, the ratio of the half-height width F to the radius D/2 of the concave portion 264 may be 0.1 or less.

In this case, the concave portion 264 may have a hexagonal shape having a diameter of 1 to 5 μm and a height of 1 to 4 μm.

As described with reference to FIGS. 4B to 5 , the concave portion 264 of the overcoating layer 260 has the same shape as the convex portion 162 of the overcoating layer 160 has a shape in which the inclination increases and then gradually decreases from the maximum inclination. ) may have a shape in which the slope increases at the bottom and gradually decreases at the maximum slope.

As described with reference to FIGS. 7A to 8 , the maximum inclination of the concave portion 264 of the overcoating layer 260 is 40 degrees, the same as the maximum inclination of the convex portion 162 of the overcoating layer 160 is 40 to 60 degrees. degrees to 60 degrees.

When the overcoating layer 260 includes the concave portion 264, the concave portion 264 is the same as the convex portion 162 of the overcoating layer 160 of the organic light emitting display device 100 described with reference to FIG. Although it has been described that it has external light extraction efficiency or luminous efficiency according to the shape of, the characteristics according to the shapes of the concave portion 264 and the second connection portion 263 according to the omitted variables are the convex portion 162 and the first connection portion ( 261) is the same as described above.

Referring to FIG. 10 , in the organic light emitting display device 300 according to the present embodiments, a plurality of data lines DL and a plurality of gate lines GL are disposed, and a plurality of subpixels SP are of a matrix type. By supplying data voltages to the organic light emitting display panel 310 and the plurality of data lines, the plurality of data lines are driven by sequentially supplying scan signals to the data driver 320 and the plurality of gate lines. It includes a gate driver 330 that sequentially drives gate lines, a data driver 320 and a controller 340 that controls the gate driver 330, and the like.

Each of the plurality of pixels disposed on the above-described organic light emitting display panel 310 includes the thin film transistor and the organic light emitting element described with reference to FIG. 1 .

According to the above-described embodiments, the organic light emitting display device has an effect of improving external light emitting efficiency and reducing power consumption.

The above description and accompanying drawings are merely illustrative of the technical idea of the present invention, and those skilled in the art can combine the configuration within the scope not departing from the essential characteristics of the present invention. , various modifications and variations such as separation, substitution and alteration will be possible. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100, 200, 300: organic light emitting display device
141, 241: first electrode
142, 142: organic light emitting layer
143, 243: second electrode
160, 260: over coating layer

Claims (12)

an over-coating layer including convex portions and concave portions disposed in the pixel region of the substrate;
a first electrode disposed on the convex and concave portions of the over-coating layer;
an organic light emitting layer disposed on the first electrode; and
A second electrode disposed on the organic light emitting layer;
The height of the convex portion is smaller than the bottom length of the convex portion,
The convex portion has a first area, a second area, and a third area divided into thirds from the bottom to the top based on the height,
An area having the thinnest thickness in the organic light emitting layer is located on a third area of the convex portion. According to claim 1,
The organic light emitting layer includes convex or concave curves,
The organic light emitting display device of claim 1 , wherein a region having the shortest thickness in the organic light emitting layer is positioned between a bottom and a top of the curved line. According to claim 2,
The organic light emitting display device of claim 1 , wherein the slope of the curvature is greatest in a region having the shortest thickness of the organic light emitting layer. According to claim 1,
The organic light emitting display device, wherein the aspect ratio of the half-height, width, and aspect ratio of the convex portion or the concave portion is greater than the aspect ratio of the convex portion or the concave portion. According to claim 4,
The organic light emitting display device, wherein the convex portion or the concave portion has a maximum inclination of 40 degrees to 60 degrees. an over-coating layer disposed in the pixel area of the substrate and including convex portions having a half-height width smaller than the radius;
a first electrode disposed on the convex portion of the overcoating layer;
an organic light emitting layer disposed on the first electrode; and
A second electrode disposed on the organic light emitting layer;
The height of the convex portion is smaller than the bottom length of the convex portion,
The organic light emitting layer has the thinnest thickness between the bottom and top of the convex portion,
The convex portion has a first area, a second area, and a third area divided into thirds from the bottom to the top based on the height,
An area having the thinnest thickness in the organic light emitting layer is located on a third area of the convex portion. delete an over-coating layer disposed in the pixel area of the substrate and including convex portions having a half-height width smaller than the radius;
a first electrode disposed on the convex portion of the overcoating layer;
an organic light emitting layer disposed on the first electrode; and
A second electrode disposed on the organic light emitting layer;
The height of the convex portion is smaller than the bottom length of the convex portion,
The organic light emitting layer has the thinnest thickness between the bottom and top of the convex portion,
The convex portion is disposed in plurality in the pixel area,
The overcoating layer further includes a connecting portion connecting two adjacent convex portions,
The thickness of the organic light emitting layer is the thinnest between the top of the convex part and the connection part. According to claim 6,
The organic light emitting display device of claim 1 , wherein the convex portion has a half-height, width, and aspect ratio greater than an aspect ratio of the convex portion. The method of any one of claims 1 to 6, 8, and 9,
The organic light emitting display device, wherein the ratio of the height to the radius of the convex part is 0.2 to 0.8, or the bottom length of the convex part is 1 to 5 μm. The method of any one of claims 1 to 6, 8, and 9,
The organic light emitting display device of claim 1 , wherein the convex portion includes a hexagonal shape, a honeycomb structure, or a hexagonal honeycomb structure in plan view. The method of any one of claims 1 to 6, 8, and 9,
The first electrode is in contact with the surface of the overcoating layer.

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