KR102520955B1 - Organic Light Emitting Diode Display Device - Google Patents

Abstract

Disclosed is an organic light emitting display device. Disclosed organic light emitting display device of the present invention includes a polarizing plate, a substrate disposed on the polarizing plate, an overcoat layer disposed on the substrate and having a plurality of microlenses, and a first electrode of an organic light emitting element disposed on the overcoat layer , an organic light emitting layer and a second electrode, the micro lens is composed of a plurality of depressions and walls surrounding the depressions, and a reflective pattern is disposed in an area corresponding to the depressions.

Description

Organic Light Emitting Diode Display Device}

The present invention relates to an organic light emitting display device including a patterned scattering layer.

An organic light emitting display device is a self-luminous display device, and unlike a liquid crystal display device, it does not require a separate light source and can be manufactured as a lightweight and thin type. In addition, the organic light emitting display device is not only advantageous in terms of power consumption due to low voltage driving, but also has excellent color implementation, response speed, viewing angle, and contrast ratio (CR), and is being studied as a next-generation display.

Light emitted from the organic light emitting layer of the organic light emitting display device passes through various components 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 particular, in an organic light emitting display having a bottom emission structure among organic light emitting display devices, total reflection or light absorption by the anode electrode causes light trapped inside the organic light emitting display device to account for about 50% of the light emitted from the organic light emitting layer, and The amount of light trapped inside the organic light emitting display device due to total reflection or light absorption by the organic light emitting layer is about 30% of the light emitted from the organic light emitting layer. As such, light efficiency is very low because about 80% of the light emitted from the organic light emitting layer is trapped inside the organic light emitting display and only about 20% of the light is extracted to the outside.

A method of attaching a micro lens array (MLA) to the outside of a substrate of the organic light emitting display or forming a micro lens on an overcoat layer of the organic light emitting display to improve the light extraction efficiency of the organic light emitting display. this is being proposed.

However, despite introducing a microlens array to the outside of the substrate of the organic light emitting display device or forming a microlens on the overcoat layer, there is a problem in that the amount of light extracted to the outside is small due to the large amount of light trapped in the device. In addition, by applying a micro lens array and a micro lens, a part of the light incident from the substrate is reflected in the same state as the polarization axis of the polarizing plate. As a result, the reflectance of the organic light emitting display device may be increased. In addition, the light generated from the organic light emitting layer passes through the substrate to reach the polarizing plate, is reflected from the polarizing plate, and is converted to a path toward the substrate. Here, some of the light traveling toward the substrate may reach micro lenses of adjacent pixels emitting different colors and cause light leakage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an organic light emitting display device capable of increasing light extraction efficiency, lowering reflectance, and preventing light leakage.

An organic light emitting display device of the present invention to solve the problems of the prior art as described above is a polarizing plate, a substrate disposed on the polarizing plate, an overcoat layer disposed on the substrate and having a plurality of micro lenses, and an overcoat layer disposed on the overcoat layer. and a first electrode, an organic light emitting layer, and a second electrode of an organic light emitting device, the microlens is composed of a plurality of depressions and walls surrounding the depressions, and a reflective pattern is formed in an area corresponding to the depressions. this is placed In this case, the width of the reflective pattern may be smaller than the maximum width of the protruding portion of the microlens.

In addition, the wall surrounding the depression is composed of a first wall and a second wall, and the first wall, the first wall and the second wall extending in a first direction form a protrusion of the microlens. In this case, the first wall and the second wall may be symmetrical to each other about a line perpendicular to the horizontal plane.

In addition, in the organic light emitting display device of the present invention, the polarizing plate has a polarization axis in a certain direction, and light incident to the substrate through the polarizing plate is reflected by the reflection pattern and converted to a direction opposite to the polarization axis of the polarizing plate. .

Further, in the organic light emitting display device of the present invention, among light incident from an area corresponding to the walls surrounding the depression, light greater than a critical angle for total reflection may reach the polarizer and then be reflected and reach the reflective pattern at least once. there is.

Further, in the organic light emitting display device of the present invention, among the light extracted from the area corresponding to the wall surrounding the depression, an angle of -30 to 30 degrees with respect to a line perpendicular to the tangent of the first wall or the second wall is applied. Incident light may reach the reflective pattern at least once.

In the organic light emitting display device according to the present invention, since the reflective pattern is disposed in an area corresponding to the recessed portion of the microlens, the external light reflectance can be reduced in proportion to the area where the reflective pattern is disposed.

In addition, the organic light emitting display device according to the present invention has an effect of preventing a light leakage phenomenon by preventing light from reaching the microlenses of other pixels due to the reflection pattern even when light traveling at an angle greater than the total reflection critical angle is generated. .

In addition, the organic light emitting display device according to the present invention propagates at an angle between -30 degrees and 30 degrees based on a line perpendicular to a straight line representing the slope of the second wall of the microlens among light generated from the organic light emitting device. By extracting light to the outside of the substrate, there is an effect of improving light efficiency.

1 is a schematic system configuration diagram of a display device according to the present embodiments.
2 is a cross-sectional view of a bottom-emission organic light emitting display device to which embodiments of the present invention are applied.
3 is a plan view illustrating an area where a microlens is disposed in a display device according to an exemplary embodiment of the present invention.
4 is a cross-sectional view of an area where a micro lens is disposed along AB in a display device according to an exemplary embodiment of the present invention.
5 is a diagram illustrating a micro lens and a reflection pattern according to another embodiment of the present invention.
6 is a diagram illustrating a micro lens and a reflection pattern according to another embodiment of the present invention.
7 is a cross-sectional view illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.
8 is a view showing positions of reflection patterns according to another embodiment of the present invention.
9 is a diagram illustrating a principle of reducing reflectance in an organic light emitting display device according to an exemplary embodiment of the present invention.
10 is a diagram illustrating a principle of suppressing a light leakage phenomenon in an organic light emitting display device according to an exemplary embodiment of the present invention.
11 is a diagram illustrating a principle of improving light extraction efficiency of an organic light emitting display device according to an exemplary embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention may be embodied in other shapes without being limited to the embodiments described below. And in the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numbers indicate like elements throughout the specification.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different shapes, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention pertains. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of explanation.

When an element or layer is referred to as “on” or “on” another element or layer, it includes both cases where another element or layer is intervening as well as directly on another element or layer. do. On the other hand, when an element is referred to as “directly on” or “directly on”, it indicates that no other element or layer is intervening.

The spatially relative terms "below, beneath", "lower", "above", "upper", etc., refer to one element or component as shown in the drawing. It can be used to easily describe the correlation between and other elements or components. Spatially relative terms should be understood as terms that include different orientations of elements in use or operation in addition to the directions shown in the figures. For example, when flipping elements shown in the figures, elements described as “below” or “beneath” other elements may be placed “above” the other elements. Thus, the exemplary term “below” may include directions both below and above.

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.

1 is a schematic system configuration diagram of a display device according to the present embodiments. Referring to FIG. 1 , a display device 1000 according to the present embodiments includes a plurality of data lines DL1 to DLm and a plurality of gate lines GL1 to GLn, and a plurality of sub pixels. The disposed display panel 1100, the data driver 1200 driving the plurality of data lines DL1 to DLm, the gate driver 1300 driving the plurality of gate lines GL1 to GLn, the data driver 1200, and A timing controller 1400 controlling the gate driver 1300 and the like are included.

The data driver 1200 drives a plurality of data lines by supplying data voltages to the plurality of data lines. The gate driver 1300 sequentially drives the plurality of gate lines by sequentially supplying scan signals to the plurality of gate lines.

Also, the timing controller 1400 controls the data driver 1200 and the gate driver 1300 by supplying a control signal to the data driver 1200 and the gate driver 1300 . The timing controller 1400 starts scanning according to the timing implemented in each frame, converts input image data input from the outside to suit the data signal format used by the data driver 1200, and outputs the converted image data. , data drive is controlled at an appropriate time according to the scan.

Under the control of the timing controller 1400, the gate driver 1300 sequentially supplies scan signals of an on voltage or an off voltage to a plurality of gate lines to sequentially drive the plurality of gate lines. . In addition, the gate driver 1300 may be located on only one side of the display panel 1100, as shown in FIG. 1, or may be located on both sides in some cases, depending on a driving method or a design method of the display panel.

In addition, the gate driver 1300 may include one or more gate driver integrated circuits. Each gate driver integrated circuit is connected to a bonding pad of the display panel 1100 using a tape automated bonding (TAB) method or a chip on glass (COG) method, or a gate in panel (GIP) type. , and may be directly disposed on the display panel 1100 or may be integrated and disposed on the display panel 1100 in some cases.

In addition, each gate driver integrated circuit may be implemented in a Chip On Film (COF) method. In this case, a gate driving chip corresponding to each gate driving integrated circuit may be mounted on a flexible film, and one end of the flexible film may be bonded to the display panel 1100 .

When a specific gate line is opened, the data driver 1200 converts the image data received from the timing controller 1400 into analog data voltages and supplies them to a plurality of data lines, thereby driving the plurality of data lines. Also, the data driver 1200 may include at least one source driver integrated circuit to drive a plurality of data lines.

Each source driver integrated circuit is connected to a bonding pad of the display panel 1100 through a tape automated bonding (TAB) method or a chip on glass (COG) method, or is directly connected to the display panel 1100. In some cases, it may be integrated and arranged on the display panel 1100 .

In addition, each source driver integrated circuit may be implemented in a Chip On Film (COF) method. In this case, a source driving chip corresponding to each source driver integrated circuit is mounted on a flexible film, one end of the flexible film is bonded to at least one source printed circuit board (Source Printed Circuit Board), and the other end is a display panel ( 1100).

The source printed circuit board is connected to the control printed circuit board through a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (FPC). A timing controller 1400 is disposed on the control printed circuit board.

In addition, a power controller (not shown) may be further disposed on the control printed circuit board to supply voltage or current to the display panel 1100, the data driver 1200, and the gate driver 1300 or to control the voltage or current to be supplied. there is. The source printed circuit board and the control printed circuit board mentioned above may be a single printed circuit board.

Meanwhile, a pixel of the present invention includes one or more subpixels. The sub-pixel refers to a unit in which a specific type of color filter is formed or an organic light emitting device can emit light of a specific color without a color filter. Colors defined in the sub-pixels may include red (R), green (G), blue (B), and optionally white (W), but the present invention is not limited thereto.

In addition, an electrode connected to a thin film transistor that controls light emission of each sub-pixel region of the display panel is referred to as a first electrode, and an electrode disposed on the entire surface of the display panel or disposed to cover two or more pixel regions is referred to as a second electrode. . When the first electrode is an anode electrode, the second electrode becomes a cathode electrode, and vice versa. Hereinafter, an anode electrode as an embodiment of the first electrode and a cathode electrode as an embodiment of the second electrode will be mainly described, but the present invention is not limited thereto.

In addition, it is a criterion that a color filter of a single color is disposed or not disposed in the aforementioned sub-pixel area. The color filter converts the color of a single organic light-emitting layer into a color of a specific wavelength. In addition, a light-scattering layer may be disposed in each sub-pixel area to increase light extraction efficiency of the organic light emitting layer. The aforementioned scattering layer may be referred to as a micro lens array, a nano pattern, a diffuse pattern, or a silica bead.

Hereinafter, examples of the scattering layer will be described focusing on the micro lens array, but the embodiments according to the present invention are not limited thereto and various light scattering structures may be combined.

2 is a cross-sectional view of a bottom-emission organic light emitting display device to which embodiments of the present invention are applied. Referring to FIG. 2 , a bottom emission type organic light emitting display device to which embodiments of the present invention are applied is a thin film including an active layer 102, a gate electrode 104, a source electrode 106, and a drain electrode 107. A transistor Tr and an organic light emitting element electrically connected to the thin film transistor Tr and including a first electrode 111, an organic light emitting layer 113, and a second electrode 114 are included.

Specifically, a buffer layer 101 is disposed on the substrate 100 . An active layer 102 of a thin film transistor Tr is disposed on the buffer layer 101 . A gate insulating layer 103 and a gate electrode 104 are disposed on the active layer 102 . An interlayer insulating layer 105 is disposed on the gate electrode 104 .

A source electrode 106 and a drain electrode 107 contacting the active layer 102 through a contact hole formed in the interlayer insulating layer 104 are disposed on the interlayer insulating layer 104 . A protective layer 108 is disposed on the source electrode 106 and the drain electrode 107 . A color filter layer 109 may be disposed on one surface of the protective layer 108 .

An overcoat layer 190 is disposed on the substrate 100 including the color filter layer 109 . The first electrode 111 of the organic light emitting device connected to the drain electrode 107 of the thin film transistor Tr is disposed on the overcoat layer 190 . A bank pattern 112 is disposed on the overcoat layer 109 to expose a portion of the upper surface of the first electrode 111 . Here, the bank pattern 112 defines an emission area and a non-emission area of the organic light emitting display device. An organic emission layer 113 is disposed on the upper surface of the first electrode 111 exposed by the bank pattern 112 and on the bank pattern 112 . On the organic light emitting layer 113, the second electrode 114 of the organic light emitting element is disposed.

In this case, the first electrode 111 may be made of a transparent conductive material, and the second electrode 114 may be made of an opaque conductive material. In addition, the second electrode 114 may be an opaque conductive material having excellent reflectivity. Through this, a bottom emission type organic light emitting display device may be implemented.

In addition, a polarizer 110 is disposed on the rear surface of the substrate 100 . The polarizing plate 110 may be a polarizing plate 110 having a polarization axis in a certain direction, and may pass only light having an axis in the same direction as the polarization axis among light incident from the rear surface of the substrate 100 . In addition, although FIG. 2 discloses the polarizing plate 110 composed of a single layer, embodiments of the present invention are not limited thereto, and the polarizing plate 110 may be composed of multiple layers.

In order to improve the light extraction effect in the organic light emitting display device having a bottom emission structure as shown in FIG. 2, an overcoat layer including a plurality of depressions or protrusions has been introduced, but the light extraction efficiency is improved by the depressions or protrusions of the overcoat layer. It appears differently for each area, and there is a problem in that the reflectance is high and the light leakage phenomenon occurs.

Embodiments of the present invention, which will be described later, are intended to solve these problems, and use a reflective pattern disposed to overlap with an overcoat layer to improve luminous efficiency of an organic light emitting display device, lower reflectance, and prevent light leakage. It can be prevented.

3 is a plan view illustrating an area where a microlens is disposed in a display device according to an exemplary embodiment of the present invention. Referring to FIG. 3 , in the display device according to the exemplary embodiment of the present invention, the area where the micro lens is disposed is divided into a first area 150, a second area 160, and a third area 155.

The first region 150 may correspond to a partial region of the recessed portion of the microlens, and the second region 160 may correspond to an area where a wall surrounding the recessed portion is disposed. Area 3 155 may correspond to a partial area of the protrusion of the microlens. Here, the first region 150 and the third region 155 may have a thickness of the organic light emitting layer of the organic light emitting device thicker than the second region 160 . That is, the first region 150, the second region 160, and the third region 155 may be divided by the thickness of the organic light emitting layer disposed on the micro lens. In this case, a reflective pattern may be disposed in the first region 150 to overlap the micro lens.

In addition, although FIG. 3 discloses that the area where the microlenses are disposed is circular, the present invention is not limited thereto, and configurations in which the microlenses are hexagonal or elliptical may also be included.

Looking at Figure 4, which is a cross-sectional view of this configuration along A-B, it is as follows. FIG. 4 is a cross-sectional view taken along A-B of an area where a microlens is disposed in a display device according to an exemplary embodiment of the present invention.

First, referring to FIG. 4, schematically examining the arrangement relationship of the overcoat layer 190 and the reflective pattern according to the embodiment of the present invention, the reflective pattern 120 and the overcoat layer 190 are disposed on the substrate 100. . At this time, the overcoat layer 190 includes a plurality of micro lenses 180 . The micro lens 180 may have a shape in which a plurality of depressions and protrusions are alternately disposed. In addition, the microlens 180 includes a plurality of first regions 150 corresponding to partial regions of the depressions.

Here, the reflective pattern 120 may be disposed in an area corresponding to the first area 150 of the micro lens 180 . In detail, the reflective pattern 120 may be disposed on an insulating layer disposed on the thin film transistor and a color filter layer disposed on the substrate 100 . Through this, the light generated from the organic light emitting device is not extracted through the first area 150, the second area 160, and the third area 155 of the micro lens 180, but is trapped in the organic light emitting display device. Light may be reflected and emitted to the outside of the substrate 100 . The light path by the reflective pattern 120 and its effect will be described in detail with reference to FIGS. 9 to 11 .

Meanwhile, in an area corresponding to the light emitting area where a plurality of microlenses are disposed, a main light emitting phenomenon due to the organic light emitting device occurs in an area corresponding to the second area 160 and the third area 155 of the microlens.

Specifically, the angle of incidence of light (emitted from the organic light emitting device) incident on the inclined surface of the microlens in the region corresponding to the second region 160 mainly gathers inside the critical angle of total reflection (about 42o), thereby causing multiple reflection (multiple reflection). reflection) to increase the light extraction efficiency. In addition, since the thickness of the organic light emitting layer 113 is the thinnest in the second region 160 , the current density is high, so that the light emitting efficiency of the organic light emitting device in the second region 160 can be high.

In addition, the third region 155 of the microlens has a low current density because the thickness of the organic light emitting layer 113 is thicker than that of the inclined surface of the microlens, but the light extraction efficiency by the microlens is very high.

As such, the reflective pattern 120 according to the present embodiment is not disposed in the regions corresponding to the second region 160 and the third region 155 of the microlens where the main emission phenomenon occurs. That is, the reflective pattern 120 according to the present exemplary embodiment may be disposed only in an area corresponding to the first area 150 of the microlens where light emission hardly occurs.

Through this, the amount of light extracted out of the substrate 100 can be increased by allowing light traveling at an angle equal to or greater than the critical angle among light emitted from the region where the main light emission phenomenon occurs to undergo additional reflection by the reflective pattern 120. . In other words, since the reflective pattern 120 is disposed in an area corresponding to the first area 150 of the microlens where the main light emitting phenomenon does not occur, higher light efficiency can be improved through additional reflection induction.

Meanwhile, the width d1 of the reflective pattern 120 may be smaller than the maximum width D1 of the protruding portion of the micro lens 180 . When the width d1 of the reflective pattern 120 is smaller than the maximum width D1 of the protruding portion of the micro lens 180, the light extraction effect through the micro lens 180 may be improved.

In detail, when the width d1 of the reflective pattern 120 is greater than the maximum width D1 of the protrusion of the micro lens 180, the path of the light extracted from the micro lens 180 to the outside of the substrate 100 is Changed, it may be trapped inside the device without finally being extracted out of the substrate 100 . That is, when the width d1 of the reflective pattern 120 is greater than the maximum width D1 of the protruding portion of the micro lens 180, the amount of light trapped in the device increases, and thus light extraction efficiency may decrease.

Meanwhile, the reflective pattern 120 may be made of a metal material. For example, it may be made of materials such as silver (Ag), copper (Gu), gold (Au), tin (Sn), aluminum (Al), etc., but the reflective pattern 120 according to the present embodiment is not limited thereto No, the reflective pattern 120 according to the present embodiment is sufficient if it is made of a metal material having a high reflectance.

The microlens 180 includes walls 130 and 140 surrounding the depression. In this case, the first wall 130 and the second wall 140 extending in the first direction may constitute the protruding part of the micro lens 180 . Since the overcoat layer 190 includes the micro lens 180 as described above, light confined inside the organic light emitting display device can be extracted to the outside of the substrate 100 to improve light efficiency.

The slopes of the walls 130 and 140 surrounding the microlenses may form an angle of 40 to 60 degrees or 120 to 140 degrees with the horizontal plane of the recessed portion.

Through this, light extraction efficiency of the micro lens 180 may be improved. In detail, the light generated from the organic light emitting device is subjected to multiple reflections due to the slopes of the walls 130 and 140 surrounding the depressions of the micro lenses, thereby increasing the amount of light emitted to the outside of the device.

Also, the shape of the micro lens 180 is not limited to that of FIG. 4 and may be a shape as shown in FIG. 5 or FIG. 6 . 5 is a diagram illustrating a micro lens and a reflection pattern according to another embodiment of the present invention. 6 is a diagram illustrating a micro lens and a reflection pattern according to another embodiment of the present invention.

Other embodiments of the present invention may include the same components as the previously described embodiments. A description overlapping with the above-described embodiment may be omitted. Also, the same components have the same reference numerals.

The difference is that the full width at half maximum (FWHM) F2 of the microlens 280 disclosed in FIG. 5 is smaller than the half maximum width F1 of the microlens 180 disclosed in FIG. 4 . Here, the half width of the microlens may be defined as the width of the convex part of the microlens at half the height of the microlens. The half-maximum width of the micro lens may be determined according to the amount of light irradiated to the material of the overcoat layer and the material of the overcoat layer in the process of forming the micro lens.

In addition, the microlens 280 according to another embodiment may also include a depression and walls 230 and 240 surrounding the depression. In addition, the slopes of the walls 230 and 240 surrounding the depressions may form an angle of 40 degrees to 60 degrees with the horizontal plane or 120 degrees to 140 degrees with the horizontal plane.

However, since the half width (F1) of the microlens 180 disclosed in FIG. 4 is larger than the half width (F2) of the microlens 180 disclosed in FIG. 5, the microlens 180 shown in FIG. 4 is recessed. The slopes of the walls 130 and 140 surrounding the portion may be smaller than the slopes of the walls 230 and 240 surrounding the recessed portion of the micro lens 280 of FIG. 5 .

As described above, the shape of the microlens according to the embodiment of the present invention can be freely adjusted by adjusting the conditions such as the amount of exposure and the material of the overcoat layer, and accordingly, a desired light extraction effect can be expected.

Also, in FIG. 5 , the reflective pattern 120 may be disposed in an area corresponding to the first area 250 of the micro lens 280 . The width d2 of the reflective pattern 120 may be smaller than the maximum width D2 of the protruding portion of the micro lens 280 .

In FIG. 6 , micro lenses 380 may be spaced apart from each other on the substrate 100 in a cross-sectional view. At this time, the microlens 380 may include a depression and walls 330 and 340 surrounding the depression. At this time, the slopes of the walls 330 and 340 surrounding the depressions of the micro lenses may form an angle of 40 to 60 degrees or 120 to 140 degrees with the horizontal plane.

In FIG. 6 , other micro lenses 380 disposed adjacent to the micro lens 380 may be spaced apart from each other. Accordingly, a separation space may be formed between the micro lens 380 and other micro lenses disposed adjacent to each other.

The microlenses 380 may be formed on the overcoat layer through a mask process, and whether or not a separation space between the microlenses 380 is formed and the width of the separation space depend on the separation distance of the mask patterns and the exposure amount in the mask process. can be determined according to

In detail, on the mask, micro lens 380 patterns for forming the micro lens 380 in the overcoat layer may be spaced apart from each other. When the separation distance between the microlens 380 patterns disposed on the mask is large, the separation distance between the microlenses 380 formed on the overcoat layer is large, and as the exposure amount during the mask process increases, the microlens ( 380) may be increased.

At this time, the separation space between the micro lens 380 and another micro lens 380 disposed adjacently may be smaller than the maximum width D3 of the protrusion of the micro lens 380 . Through this, the light extraction effect through the micro lens 380 can be improved.

Meanwhile, a reflective pattern 120 may be disposed in an area corresponding to a separation space formed between the micro lenses 380 . Since the reflective pattern 120 is disposed in the spaced space between the micro lenses 380, even when the color filter layer (not shown) is exposed by the spaced space, reflection is reflected on the exposed color filter layer (not shown). A pattern 120 may be disposed to prevent the color filter layer (not shown) from being exposed. Through this, outgassing by the color filter layer (not shown) can be prevented.

Here, the width d3 of the reflective pattern 120 may be smaller than the maximum width D3 of the protruding portion of the micro lens 380 . Through this, the light extraction effect by the reflective pattern 120 can be improved.

As described above, micro patterns of various shapes may be applied to the organic light emitting display device according to the present invention.

A detailed cross-sectional view of the organic light emitting display device to which the plurality of micro lenses and the plurality of reflection patterns are applied is as follows. 7 is a cross-sectional view illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 7 , a plurality of micro lenses 180 are formed on an overcoat layer 190 in an organic light emitting display device according to an exemplary embodiment of the present invention. In this case, the plurality of micro lenses 180 may be formed to overlap the color filter layer 109 disposed on the protective layer 108 .

In addition, the plurality of micro lenses 180 may be disposed at positions corresponding to the light emitting area among the light emitting area and the non-light emitting area defined by the bank pattern 112 . As such, since the plurality of micro lenses 180 are disposed only in the region corresponding to the light emitting region, light emitted from the organic light emitting device can be extracted to the outside of the substrate 100 . That is, the plurality of micro lenses 180 are disposed only in areas necessary for light extraction. Through this, light extraction efficiency may be improved. A plurality of reflective patterns 120 may be disposed on the color filter layer 109 to correspond to the depressions.

The first electrode 111 of the organic light emitting element EL connected to the drain electrode 107 of the thin film transistor Tr is disposed on the overcoat layer 190 . Here, the first electrode 111 may be formed according to the morphology of the overcoat layer 190 as it is. That is, the first electrode 111 may have recessed portions and protruding portions alternately disposed in an area corresponding to the area where the micro lens 180 is formed in the overcoat layer 190 .

In addition, the organic light emitting layer 113 and the second electrode 114 of the organic light emitting element EL disposed on the first electrode 111 are also formed in the area where the micro lens 180 is formed in the overcoat layer 190 and In corresponding areas, the depressions and protrusions may be alternately disposed. That is, the reflective pattern 120 may be disposed in an area corresponding to the depressions of the first electrode 111 , the organic light emitting layer 113 , and the second electrode 114 of the organic light emitting element EL. Again, the reflective pattern 120 may be disposed in an area corresponding to the recessed portion of the plurality of micro lenses 180 in the light emitting area (an area where the bank pattern is not disposed).

In addition, although FIG. 7 shows an organic light emitting display device to which a micro lens 180 according to an embodiment of the present invention is applied, the present invention is not limited thereto, and micro lenses according to other embodiments as described above are not limited thereto. may be applied.

Next, with reference to FIG. 8, the position of the reflection pattern according to another embodiment of the present invention is reviewed as follows. 8 is a view showing positions of reflection patterns according to another embodiment of the present invention. 8 may include the same components as those of the previously described embodiment. A description overlapping with the above-described embodiment may be omitted. Also, the same components have the same reference numerals.

Referring to FIG. 8 , the reflective pattern 220 according to another embodiment of the present invention may be disposed between the overcoat layer 290 and the first electrode 211 in a region corresponding to the depression of the overcoat layer 290. there is. That is, the reflective pattern 220 may be disposed on the overcoat layer 290 in an area corresponding to the recessed portion of the overcoat layer 290 and disposed below the first electrode 211 .

As described above, when the reflective pattern 220 is located, an overcoat layer 290 having a plurality of micro lenses is formed. Thereafter, a metal layer is formed on the overcoat layer 290, and a photoresist is formed on the metal layer. Then, the metal layer is wet etched to form the reflective pattern 220 in a region corresponding to the recessed portion of the overcoat layer 290 .

As such, the reflective pattern 220 is disposed on the overcoat layer 290 to prevent irregular formation of a plurality of microlenses due to moisture and impurities that may occur during exposure during the forming process of the reflective pattern 220. can do. Specifically, the reflective pattern 220 according to the present embodiment is formed after the overcoat layer 290 including a plurality of micro lenses is formed, due to impurities generated in the process of forming the reflective pattern 220. Irregular formation of microlenses can be prevented.

Meanwhile, the depressed portion of the overcoat layer 290 may be formed flatter than the depressed portion of the overcoat layer 190 shown in FIG. 4 , but the present embodiment is not limited thereto. In addition, the first electrode 211, the organic light emitting layer 213, and the second electrode 214 disposed on the reflective pattern 220 are regions corresponding to the depressions of the overcoat layer 290 by the reflective pattern 220. may be formed flatter than the first electrode 111, organic light emitting layer 113, and second electrode 114 shown in FIG. 4, but the present embodiment is not limited thereto.

Such an organic light emitting display device has effects of reducing reflectance, preventing light leakage, and improving light extraction efficiency. This will be described with reference to FIGS. 9 to 11.

9 is a diagram illustrating a principle of reducing reflectance in an organic light emitting display device according to an exemplary embodiment of the present invention. For convenience of explanation, a configuration in which the reflective pattern 120 is disposed under the overcoat layer 190 in the organic light emitting display device according to the present exemplary embodiment will be mainly described. A component disposed on the upper portion of the reflective pattern 120 and the overcoat layer 190 may also have a reduced reflectance according to the same principle as will be described later. Referring to FIG. 9 , an overcoat layer 190 having a plurality of reflection patterns 120 and a plurality of micro lenses 180 according to an embodiment of the present invention is disposed on a substrate 100 . In addition, a polarizer 110 is disposed on the substrate 100 . The polarizing plate 110 may include a polarizing plate having a polarization axis of a certain direction and a polarizing plate having a phase retardation value of a certain value overlapping each other.

Here, the external light 500 incident from the rear surface of the substrate 100 passes through the polarizing plate 110 while only passing light in the same direction as the polarization axis of the polarizing plate 110 . Then, the light polarized in a certain direction is circularly polarized with a certain phase delay value and is incident on the substrate 100 . The light incident on the substrate 100 is reflected by the second electrode 114 of the organic light emitting diode EL and is delayed by 180 degrees from the light passing through the polarizer 110 . The phase-delayed light may change its path toward the substrate 100 again.

Meanwhile, since the overcoat layer 190 includes a plurality of micro lenses 180, the first electrode 111, the organic light emitting layer 113, and the second electrode 114 of the organic light emitting element EL also have depressions and protrusions. have a shape in which are arranged alternately. Here, the second electrode 114 reflects light incident from the substrate 100, and at this time, a part of the reflected light is converted in a direction opposite to the polarization axis of the polarizer 110.

However, since the second electrode 114 is not formed flat, the remaining part of the light incident from the substrate 100 is reflected in the same state as the polarization axis of the polarizer 110 . As a result, the reflectance of the organic light emitting display device may be increased.

Meanwhile, in the embodiment of the present invention, the reflection pattern 120 is disposed in an area corresponding to the depression of the micro lens 180 formed in the overcoat layer 190 . The reflective pattern 120 may be disposed on an insulating layer disposed on the thin film transistor and a color filter layer disposed on the substrate 100 . At this time, light in the same direction as the polarization axis of the polarizing plate 110 is incident and is circularly polarized to have a constant phase retardation value, and the circularly polarized light is incident to the substrate 100 . Light incident on the substrate 100 is reflected by the reflective pattern 120 , and the path of the light reflected by the reflective pattern 120 is changed toward the substrate 100 .

The light whose path is changed in the direction of the substrate 100 passes through the polarizer having the constant phase retardation value and reaches the polarizer having the constant polarization axis, but the light whose path is changed in the direction of the substrate 100 has the constant phase retardation value. While passing through the polarizer, the polarization direction may be switched in a direction opposite to the polarization axis of the polarizer having a constant polarization axis.

Therefore, the light reflected by the reflective pattern 120 is not emitted to the outside of the substrate 100 . That is, the reflectance by the external light 500 may be lowered in the region where the reflective pattern 120 is disposed.

In other words, in the embodiment of the present invention, reflection of external light 500 is prevented in the area where the reflection pattern 120 is disposed by disposing the reflective pattern 120 in an area corresponding to the depression of the micro lens 180. There are effects that can be done. Through this, the display device according to the embodiment of the present invention can lower the reflectance of the external light 500 in proportion to the disposition area of the reflective pattern 120 .

Next, with reference to FIG. 10 , a principle of suppressing light leakage of an organic light emitting display device according to an exemplary embodiment of the present invention will be described. For convenience of explanation, a configuration in which the reflective pattern 120 is disposed under the overcoat layer 190 in the organic light emitting display device according to the present exemplary embodiment will be mainly described. Light leakage can also be suppressed in a configuration disposed on the upper portion of the reflective pattern 120 and the overcoat layer 190 by the same principle as will be described later. 10 is a diagram illustrating a principle of suppressing a light leakage phenomenon in an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 10 , a plurality of reflection patterns 120 according to an embodiment of the present invention, an overcoat layer 190 including a plurality of micro lenses 180, and an organic light emitting element EL are disposed on a substrate 100. do. In this case, the refractive index of the first electrode 111 and the organic light emitting layer 113 of the organic light emitting element EL may be greater than the refractive index of the substrate 100 and the overcoat layer 190 . For example, the refractive index of the substrate 100 and the overcoat layer 190 may be about 1.5, and the refractive index of the first electrode 111 and the organic light emitting layer 113 of the organic light emitting element EL may be between 1.7 and 2.0. .

At this time, part of the light emitted from the organic light emitting layer 113 is reflected by the second electrode 114 and the light path is switched in the direction of the first electrode 111, and the remaining part is directed toward the first electrode 111. is issued with That is, most of the light generated by the organic light emitting layer 113 is directed toward the first electrode 111 .

Here, since the refractive index of the organic light emitting layer 113 and the first electrode 111 are almost the same, the light generated from the organic light emitting layer 113 has a light path at the interface between the organic light emitting layer 113 and the first electrode 111. It doesn't change. Meanwhile, the light passing through the first electrode 111 has a critical angle at the interface between the first electrode 111 and the overcoat layer 190 due to a difference in refractive index between the first electrode 111 and the overcoat layer 190 . The incident light may be totally reflected.

At this time, the light totally reflected at the interface between the first electrode 111 and the overcoat layer 190 passes through the substrate 100 having almost the same refractive index as the overcoat layer 190 and reaches the polarizer 110, The light is reflected back from the polarizer 110 and the path is converted toward the substrate 100 . Here, some of the light traveling toward the substrate 100 may reach the micro lenses 180 of adjacent pixels emitting different colors and cause light leakage.

On the other hand, in the embodiment of the present invention, the reflective pattern 120 is disposed in an area corresponding to the depression of the micro lens 180 formed in the overcoat layer 190, so that light traveling at an angle greater than the critical angle (a) for total reflection This is prevented from reaching the micro lenses 180 of other adjacent pixels.

In detail, light generated in the organic light emitting layer 113 is totally reflected at the interface between the first electrode 111 and the overcoat layer 190, and here, the light traveling at an angle greater than the critical angle a for total reflection is the overcoat layer ( 190) and the substrate 100, the light is reflected again at the interface between the substrate 100 and the polarizer 110, and the light path is converted to the direction of the substrate 100.

Thereafter, the light path changed in the direction of the substrate 100 passes through the substrate 100 again and reaches the reflective pattern 120 disposed on the substrate 100 . The light reaching the reflective pattern 120 is reflected by the reflective pattern 120 and the path is converted to the direction of the polarizing plate 110, and the light reaching the polarizing plate 110 passes through the substrate 100 again and is reflected. Pattern 120 is reached.

That is, when light traveling at an angle greater than the critical angle of total reflection (a) reaches the reflective pattern 120 at least once after reaching the polarizer 110 , it may be confined to the substrate 100 . Accordingly, light traveling at an angle greater than the total reflection critical angle (a) remains confined to the substrate 100 .

As described above, in the organic light emitting display device according to an exemplary embodiment of the present invention, even when light traveling at an angle greater than the total reflection critical angle (a) is generated, the reflection pattern 120 reaches the microlens 180 of another pixel. By preventing this, there is an effect of preventing light leakage.

Next, referring to FIG. 11 , a principle of improving light extraction efficiency of an organic light emitting display device according to an exemplary embodiment of the present invention will be described. 11 is a diagram illustrating a principle of improving light extraction efficiency of an organic light emitting display device according to an exemplary embodiment of the present invention. For convenience of explanation, a configuration in which the reflective pattern 120 is disposed under the overcoat layer 190 in the organic light emitting display device according to the present exemplary embodiment will be mainly described. Light extraction efficiency may be improved in a structure disposed on the reflective pattern 120 and the overcoat layer 190 according to the same principle as will be described later.

Referring to FIG. 11 , on a substrate 100, a plurality of reflection patterns 120 according to an embodiment of the present invention, an overcoat layer 190 including a plurality of micro lenses 180, and an organic light emitting element EL are disposed. do.

The micro lens 180 is divided into a first area 150, a second area 160, and a third area 155, and the light extraction efficiency is the highest in the second area 160. In detail, the second region 160 has the thinnest thickness of the organic light emitting layer 113 following the morphology of the overcoat layer 190, so that the current density is high. Accordingly, since an electric field is strongly applied to the second region 160 , main light emission occurs in the organic light emitting device disposed in the region corresponding to the second region 160 .

In addition, due to the slope formed in the second region 160 of the micro lens 180, light extraction efficiency generated from the organic light emitting device is highest in the second region 160. For example, when the micro lens 180 is composed of a depression, a first wall 130 surrounding the depression, and a second wall 140 extending in a first direction from the first wall 130 , When the light generated from the organic light emitting device is incident on the first wall 130 of the second area 160 of the micro lens 180, it collides with the first wall 130 or the second wall 140 As a result, the amount of light extracted out of the substrate 100 increases.

In other words, the light generated from the organic light emitting element EL is incident on the second wall 140 of the micro lens 180, and a line perpendicular to the tangential line of the second wall 140 among the incident light As a reference, light traveling at an angle between -30 degrees and -90 degrees or at an angle between 30 degrees and 90 degrees collides with the second wall 140 and the first wall 130 extending in the first direction, It is extracted out of the substrate 100 .

In addition, among the light generated from the organic light emitting element EL, the light traveling at an angle between -30 degrees and 30 degrees based on a line perpendicular to the tangent of the second wall 140 is the second wall ( 140) and the first wall 130 extending in the first direction, it is not extracted out of the substrate 100 and is trapped inside the device.

Meanwhile, in the organic light emitting display device according to the exemplary embodiment of the present invention, light extraction efficiency is further improved by disposing the reflective pattern 120 in an area corresponding to the recessed portion of the microlens 180 formed in the overcoat layer 190. It can be.

In detail, among the light generated from the organic light emitting element EL, the light traveling at an angle between -30 degrees and 30 degrees based on a line perpendicular to the straight line representing the slope of the second wall 140 is It reaches the reflective pattern 120 disposed in an area corresponding to the depression of the micro lens 180 .

The light reaching the reflective pattern 120 reaches another micro lens 180 adjacent to the micro lens 180 into which the light generated from the organic light emitting element EL is incident, and is extracted out of the substrate 100 .

As such, light incident at an angle of -30 degrees to 30 degrees based on a line perpendicular to the tangent of the second wall 140 reaches the reflection pattern 120 at least once, and through this, the first Based on a line perpendicular to the tangential line of the second wall 140, the light traveling at an angle between -30 degrees and -90 degrees or between 30 degrees and 90 degrees may be converted into light and extracted out of the substrate 100. .

Although the foregoing example has been described with reference to the second wall 140 of the micro lens 180, the light extracted through the first wall 130 of the micro lens 180 also goes through the same process as the substrate 100. ) can be extracted out.

As described above, in the organic light emitting display device according to the exemplary embodiment of the present invention, the light emitted from the organic light emitting element EL is between -30 degrees and 30 degrees based on a line perpendicular to the tangential line of the second wall 140. By extracting out of the substrate 100 up to the light traveling at an angle of , there is an effect of improving light efficiency.

As described above, the organic light emitting display device according to an embodiment of the present invention has a low reflectance because the reflective pattern 120 is disposed in an area corresponding to the recessed portion of the microlens 180 formed in the overcoat layer 190. There is an effect of preventing light leakage and improving light extraction efficiency.

The features, structures, effects, etc. described in the foregoing embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified with respect to other embodiments by those skilled in the art in the field to which the embodiments belong. Therefore, contents related to these combinations and variations should be construed as being included in the scope of the present invention.

In addition, although the embodiments have been described above, these are merely examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention belongs can exemplify the above to the extent that does not deviate from the essential characteristics of the present embodiment. It will be seen that various variations and applications that have not been made are possible. For example, each component specifically shown in the embodiments can be modified and implemented.

1000: transparent display device
1100: transparent display panel
1200: data driving unit
1300: gate driver
1400: timing controller

Claims (14)

polarizer;
a substrate disposed on the polarizing plate;
an overcoat layer disposed on the substrate and having a plurality of micro lenses; and
A first electrode, an organic light emitting layer, and a second electrode of the organic light emitting device disposed on the overcoat layer and having a curve according to the shape of the micro lens;
The micro lens is formed of a plurality of depressions and walls surrounding the depressions, and a reflective pattern is disposed in an area corresponding to the depressions.
According to claim 1,
The organic light emitting display device of claim 1 , wherein a wall surrounding the depression constitutes a protrusion of the microlens.
According to claim 2,
The micro lens is an organic light emitting display device in which depressions and protrusions are alternately disposed.
According to claim 1,
The organic light emitting display device of claim 1 , wherein the slope of the wall surrounding the recessed portion has an angle between 40 and 60 degrees or 120 and 140 degrees with respect to a horizontal plane.
According to claim 1,
The organic light emitting display device wherein the microlenses are spaced apart from other adjacent microlenses, and a reflective pattern is disposed in an area corresponding to the spaced space.
According to claim 1,
The polarizer has a polarization axis in a certain direction,
The organic light emitting display device of claim 1 , wherein light incident to the substrate through the polarizing plate is reflected by the reflective pattern and is converted in a direction opposite to a polarization axis of the polarizing plate.
According to claim 1,
The organic light emitting display device of claim 1 , wherein refractive indices of the first electrode and the organic light emitting layer are greater than those of the overcoat layer and the substrate.
According to claim 1,
Of the light incident in an area corresponding to the walls surrounding the depression,
The organic light emitting display device of claim 1 , wherein light greater than the critical angle of total reflection is reflected after reaching the polarizer and reaching the reflective pattern at least once.
According to claim 1,
Of the light incident on the area corresponding to the wall surrounding the depression,
The organic light emitting display device of claim 1 , wherein light incident at an angle of -30 degrees to 30 degrees relative to a line perpendicular to a wall surrounding the depression reaches the reflective pattern at least once.
According to claim 1,
The organic light emitting display device of claim 1 , wherein a width of the reflection pattern is smaller than a maximum width of the protrusion of the micro lens.
According to claim 1,
The reflective pattern is in an area corresponding to the depression,
An organic light emitting display device disposed on a color filter layer disposed on the substrate or an insulating layer disposed on a thin film transistor.
According to claim 1,
The reflective pattern is in an area corresponding to the depression,
An organic light emitting display device disposed between the overcoat layer and the first electrode.
According to claim 1,
Further comprising a bank pattern disposed between the overcoat layer and the first electrode and defining a light emitting area and a non-emitting area,
The plurality of micro lenses are provided in an area corresponding to the light emitting area.
According to claim 1,
The plurality of microlenses may include a first region corresponding to a partial region of the depression, a second region corresponding to an region where a wall surrounding the depression is disposed, and a third region corresponding to a partial region of the protrusion of the plurality of microlenses. separated by
The reflective pattern is positioned in an area corresponding to the first area.

Images