KR20190054723A - Electroluminescence display device - Google Patents

Abstract

An electroluminescent display device of the present invention is provided to minimize light loss. The electroluminescent display device comprises: a light emitting device comprising a first electrode and a second electrode, and arranged between the first electrode and the second electrode; and an optical path control layer arranged on an output side of the light emitting device, and having an optical path for totally reflecting light inside the light emitting device.

Description

ELECTROLUMINESCENCE DISPLAY DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to an electroluminescent display device, and more particularly, to an electroluminescent display device capable of improving optical efficiency by forming an optical path using transflective reflection.

Recently, an electroluminescent device using poly (p-phenylenevinylene) (PPV), which is one of conjugate polymers, has been developed and research on organic materials such as conjugated polymers having conductivity has been actively conducted. Studies for applying such organic materials to thin film transistors (TFTs), sensors, lasers, photoelectric elements, etc. have been continuing, and researches on electroluminescent display devices have been actively conducted.

In the case of an electroluminescence display device made of a phosphorescent inorganic material, since the driving voltage is required to be 200 V or more in AC and the manufacturing process of the device is made by vacuum deposition, it is difficult to increase the size, . However, the electroluminescent display device made of an organic material has advantages in that it can develop an electroluminescent display device that can exhibit excellent luminescence efficiency, easiness of face-to-face, simplicity of process, especially blue light emission, It is popular as a next generation display device.

Currently, an active matrix electroluminescent display device having an active driving element in each pixel is actively studied as a panel display device in the same manner as a liquid crystal display device.

However, in the electroluminescent display device described above, only about 20% of the light emitted from the light emitting layer is output to the outside, and about 80% of the light is lost, so that the light extraction efficiency is low.

An object of the present invention is to provide an electroluminescent display device capable of minimizing light loss at an interface by changing the path of output light.

An electroluminescent display device according to one aspect of the present invention includes: a light emitting element formed of a first electrode and a second electrode, a first electrode, and a light emitting layer disposed between the second electrode and a light emitting element disposed on an output side of the light emitting element, And an optical path control layer having a light path for totally reflecting light inside.

According to another aspect of the present invention, an electroluminescent display includes a first substrate including a transistor, a light emitting element disposed on the transistor, the light emitting element including a first electrode, a light emitting layer, and a second electrode, A second substrate, and a first substrate and a second substrate. And an optical path control layer for totally reflecting the light inside the light emitting element.

The present invention provides an optical path control layer having a first region of low refractive index and a second region of high refractive index on the output side of a light emitting device including a light emitting layer and is then output to the outside through the optical path control layer, The angle of incidence of light can be reduced to a critical angle or less of the interface so that reflection and refraction of light at the interface can be minimized and light loss due to light refraction and reflection at the interface can be minimized.

In the present invention, the optical path control layer is provided on the side from which light is outputted, thereby changing the path of light incident on the interface between the layers at a critical angle or more to change the incident angle to a critical angle or less, Can be minimized.

In addition, since the optical path control layer can be formed in the form of a film and attached to the electroluminescence display device, the present invention can simplify the process and reduce the manufacturing cost of the display device.

1 is a cross-sectional view illustrating a structure of an electroluminescent display device according to a first embodiment of the present invention.
2 is a plan view of an optical path control layer of an electroluminescent display device according to a first embodiment of the present invention.
3 is a view showing propagation of light of an optical path control layer according to the present invention;
4 is a cross-sectional view illustrating a structure of an electroluminescent display device according to a first embodiment of the present invention.
5 is a flow chart showing a method of manufacturing an electroluminescent display device according to the present invention.
6A to 6E are views showing a method of manufacturing an electroluminescent display device according to the present invention.
7 is a perspective view showing a structure of an optical path control layer according to the present invention.
8A to 8C are plan views showing an optical path control layer of an electroluminescent display device according to a second embodiment of the present invention.
9 is a sectional view showing a structure of an electroluminescent display device according to a third embodiment of the present invention.
10 is a cross-sectional view illustrating an electroluminescent display device according to a third embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if the temporal relationship is described by 'after', 'after', 'after', 'before', etc., May not be continuous unless they are not used.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Generally, the reason why the light efficiency of the electroluminescence display device is low is as follows.

First, the light efficiency is lowered due to the waveguide phenomenon in the electroluminescence display device. The electroluminescence display device is composed of a plurality of layers having different refractive indexes. Therefore, when the light emitted from the light emitting layer is output to the outside through a plurality of lights, the light is refracted and propagated at a certain angle due to the difference in refractive index at the interface between the plurality of layers. For example, when the incident angle of the light incident on the interface of the layer is greater than the critical angle with respect to the normal, the incident light is reflected at the interface, and the reflected light propagates along the inside of the layer without being output to the outside. Therefore, a part of light emitted from the light emitting layer can not be outputted to the outside, and is confined inside the EL display device.

Second, the light efficiency of the electroluminescence display device is lowered by the surface plasmon. Surface plasmons are waves that propagate along the interface between a waveguide metal and a dielectric material caused by the collective oscillation of electrons in the metal film. The electric field of the light in the visible light band among the light emitted from the light emitting layer is paired with the surface plasmon, so that light absorption occurs, and a substantial part of the light is lost in the form of surface plasmon.

In the present invention, efficiency deterioration due to a difference in refractive index between layers and layers among the causes of reduction in efficiency of the electroluminescence display device is prevented, and will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view illustrating a structure of an electroluminescent display device according to a first embodiment of the present invention.

1, an electroluminescent display device according to an embodiment of the present invention includes a first electrode 130 and a second electrode 134 formed on a first substrate 110, A light emitting layer 132 disposed between the second electrodes 134 to emit light as a signal is applied thereto and an optical path control unit 130 disposed on the second electrode 134 to control a path of light output from the light emitting layer 132. [ Layer 150 and a second substrate 160 attached to the optical path control layer 150 by an adhesive layer 162.

The electroluminescence display device is a top emission display device in which light emitted from the light emitting layer 133 is output in an upward direction through the light path control layer 150. The first electrode 130 is an anode and is formed of a metal and a metal alloy having good reflectance such as Ca, Ba, Mg, Al, and Ag. The first electrode 130 applies a signal to the emission layer 132, And reflects the light incident thereon.

The first electrode 130 may be an electrode for applying a signal to the light emitting layer 132. The first electrode 130 may emit light from the light emitting layer 132 and enter the downward direction to reflect light upward, It may be a reflector which improves the reflectivity.

Therefore, in this embodiment, the first electrode 130 may be formed of a transparent material or a semi-transparent material, and a reflective layer made of a material having a high reflectivity such as metal may be disposed below the first electrode 130.

The second electrode 134 is a cathode and is made of a transparent metal oxide such as ITO (indium tin oxide) or IZO (Indium Zinc Oxide), and the light emitted from the light emitting layer 132 and the light emitted from the first electrode 130 And outputs the reflected light to the outside to display an image.

The light emitting layer 132 may be a monochromatic light emitting layer in which R, G, and B monochromatic light are emitted, or may be a white light emitting layer in which white light is emitted. When the light emitting layer 132 is a white light emitting layer, the light emitting layer 132 may be formed of a mixture of a plurality of organic materials that emit red, green, and blue monochromatic light, or a plurality of And a color filter layer may be formed on the light emitting layer 132. The color filter layer may be formed on the light emitting layer 132. [ The organic light emitting layer 132 may be formed of an inorganic layer. For example, the light emitting layer may be a quantum dot.

The light emitting layer 132 includes a light emitting layer that emits light when a voltage is applied from the first electrode 130 and the second electrode 134, an electron injection layer and a hole injection layer that inject electrons and holes into the light emitting layer, respectively, An electron transport layer and a hole transport layer that transport the injected electrons and holes to the organic layer, respectively.

The light path control layer 150 is provided to improve the light efficiency of the electroluminescence display device by propagating the path of the light emitted from the light emitting layer 132 in the vertical direction perpendicular to the light emitting layer 132, 1 region 151 and a second region 153 of high refractive index material. The first region 151 is made of a polymer material having a relatively low refractive index and the second region 153 is made of a polymer material having a higher refractive index than the first region 151.

For example, the refractive index of the first region 151 is less than about 1.4 and the refractive index of the twenty-first region 153 is not less than 1.4, but is not limited thereto. The polymer material may be PMMA (Polymethylmethacrylate), PVA (Poly Vinyl Alcohol), Photo Acryl, OCA (Optical Cleared Adhesive) or the like, but is not limited thereto.

2 is a plan view of an optical path control layer 150 of an electroluminescent display device according to the first embodiment of the present invention. The electroluminescent display device may be composed of pixels P arranged in the vertical and horizontal directions (where n and m are natural numbers) and the light path control layer 150 may be arranged in a plurality of pixels, Three pixels P are shown.

2, the optical path control layer 150 corresponding to each pixel P of the electroluminescence display device includes a first region 151 having a low refractive index and a plurality of second regions 151 formed in the first region 151 And a second area 153. The first region 151 may be continuously formed over the entire area of the pixel P, for example, over the entire area of the electroluminescence display device, and the second region 153 may be formed continuously in the first region 151). ≪ / RTI >

Although the second region 153 has a cylindrical shape with a diameter d1 of about 400 nm and an interval d2 and d3 in the x and y directions of about 20 nm, the second region 153 has such a specific value But is not limited to a cylindrical shape. Since the second region 153 serves as a path for propagating light, the second region 153 is formed in various shapes and sizes according to various factors such as the resolution of the electroluminescence display device, the shape and size of the pixel, and the like. .

2, the second regions 153 may be regularly arranged in a matrix within the pixels P, and the second regions 153 may be irregularly arranged in the pixels P .

The second region 153 of the optical path control layer 150 is formed in a cylindrical shape (extending outward from the light emitting layer 132 of the display device) surrounded by the first region 151 in the first region 151 And a light guide plate that totally reflects incident light of a cylindrical shape and outputs the light to the outside. The description will be made with reference to FIG. 3 as follows.

3, a second region 153 having a refractive index of n2 is formed in a first region 151 having a refractive index of n1, and the second region 153 is formed in a first region 151, . The refractive index n1 of the first region 151 and the refractive index n2 of the second region 153 are n2 > n1.

The light a emitted from the light emitting layer 132 and incident on the interface between the first region 151 and the second region 153 in the second region 153 is incident on the cylindrical region 153 of the second region 153, The light output from the light emitting layer 132 is propagated through the inside of the second region 153 and then output to the outside of the display device. By adjusting the refractive index n1 of the first region 151 and the refractive index n2 of the second region 153, the critical angle (n1) at the interface between the first region 151 and the second region 153 can be set.

For example, according to Snell's law, as the difference between the refractive index n2 of the second region 153 and the refractive index n1 of the first region 151 increases, the critical angle c decreases, And the second region 153 are increased. When n2 is twice as large as n1, since the critical angle c is 30 degrees, light incident at an angle of 30 degrees or more is totally reflected at the interface between the first region 151 and the second region 153, and n2 is three times as large as n1 The incident light at an angle of 19.47 degrees or more is totally reflected at the interface between the first area 151 and the second area 153 and is propagated to the outside of the display device and outputted.

Light b emitted from the light emitting layer 132 and incident on the first region 151 of the optical path control layer 150 at an angle of? 1 from the first region 151 to the second region 153 is incident on the first region 151 and the second region 153, The light is refracted at the interface of the region 153 and propagated to the inside of the second region 153 at an angle of &thetas; 2, and the light incident into the second region 153 is totally reflected inside the second region 153 And output to the outside of the apparatus.

Since the light path control layer 150 propagates in the second region 153 serving as a light guide plate, all the light emitted from the light emitting layer 132 is incident on the light path control layer 150, It is possible to straighten the display device in the outward direction. Therefore, the light output to the outside of the display device is reflected by the interface between the plurality of layers (for example, the interface between the optical path control layer 150 and the adhesive layer 162, the interface between the adhesive layer 162 and the second substrate 160) The interface between the second substrate 160 and the outside air layer), it is possible to reduce the angle of incidence of light, thereby reducing light refraction at the interface. Therefore, it is possible to reduce the phenomenon that the outputted light is refracted in each layer of the display device and is not outputted and lost inside the layer.

The second region 153 may be referred to as an optical path because the second region 153 can serve as a path through which the light propagates substantially in the optical path control layer 150.

4 is a view illustrating a structure of an electroluminescent display device according to a first embodiment of the present invention.

As shown in FIG. 4, a buffer layer 112 is formed on the first substrate 110, and a driving thin film transistor is disposed thereon. The substrate 110 is made of a transparent material such as glass, but transparent and flexible plastic such as polyimide may be used. The buffer layer 112 may be formed of a single layer or a plurality of layers.

The driving thin film transistor is formed in each of the plurality of pixel regions. The driving thin film transistor includes a semiconductor layer 122 formed on a pixel region on the buffer layer 112, a gate insulating layer 123 formed on a partial region of the semiconductor layer 122, An interlayer insulating layer 114 formed over the entire substrate 110 to cover the gate electrode 125 and a first contact hole 114a formed in the interlayer insulating layer 114, And a source electrode 127 and a drain electrode 128 which are in contact with the semiconductor layer 122 through the gate electrode 122. [ The semiconductor layer 122 may be in contact with the source electrode 127 through the first contact hole 114a formed in the interlayer insulating layer 114. [

The semiconductor layer 122 may be formed of crystalline silicon or an oxide semiconductor such as IGZO (Indium Gallium Zinc Oxide). The semiconductor layer 122 may include a channel layer in the central region and a doped layer on both sides. The source electrode 127 and the drain electrode 128 ) Is in contact with the doped layer.

The gate electrode 125 is Cr, Mo, Ta, Cu, Ti, may be formed of a metal such as Al or an Al alloy, a gate insulating layer 123 and the interlayer insulating layer 114, such as SiO _x or SiNx a single-layer or two-layer structure of SiO _x and SiNx made of the inorganic insulating material may be formed of an inorganic layer. The source electrode 127 and the drain electrode 128 may be formed of Cr, Mo, Ta, Cu, Ti, Al, or Al alloy.

In the drawings and the above description, the driving thin film transistor has a specific structure. However, the driving thin film transistor of the present invention is not limited to the illustrated structure, but a driving thin film transistor of any structure can be applied.

The first passivation layer 116 is formed on the substrate 110 on which the driving thin film transistor is formed. The first passivation layer 116 may be formed of an organic material such as photoacryl. A second contact hole 116a is formed in the first passivation layer 116. [

A first electrode 130 electrically connected to the drain electrode 128 of the driving thin film transistor is formed on the first passivation layer 116 through a second contact hole 116a. The first electrode 130 is formed of a single layer or a plurality of layers made of a metal such as Ca, Ba, Mg, Al, Ag or the like or an alloy thereof and is connected to the drain electrode 128 of the driving TFT. An image signal is applied.

A bank layer 131 is formed at the boundary of each pixel P on the first electrode 130. The bank layer 131 is a kind of barrier rib, and it is possible to prevent each pixel P from being mixed to output light of a specific color outputted from adjacent pixels. The bank layer 131 is formed on the first electrode 130 and the bank layer 131 is formed on the first protective layer 116 and the first electrode 130 is formed on the bank layer 131 .

A light emitting layer 132 is formed on the first electrode 130 and the bank layer 131. The emission layer 132 may be an R-emission layer formed on R, G, or B pixels to emit red light, a G-emission layer that emits green light, or a B-emission layer that emits blue light. Emitting layer. When the light layer 132 is a white light emitting layer, R, G, and B color filter layers are formed in an upper region of the white light emitting layer 132 in the R, G, and B pixel regions to convert white light emitted from the white light emitting layer into red light, . The white light emitting layer may be formed by mixing a plurality of organic materials that emit red, green, and blue monochromatic light, respectively, or a plurality of light emitting layers that emit red, green, and blue monochromatic light, respectively. The light emitting layer may be composed of an inorganic light emitting layer. For example, it may be a quantum dot.

The light emitting layer 132 may include not only the light emitting layer but also an electron injection layer for injecting electrons and holes into the light emitting layer, and an electron transport layer and a hole transport layer for transporting the injected electrons and holes to the organic layer, respectively.

A second electrode 134 is formed on the light emitting layer 132. The second electrode 134 may be formed of a transparent material such as indium tin oxide (ITO) or indium zinc oxide (IZO), but is not limited thereto.

A planarization layer 118 is formed over the entire surface of the substrate 110 on the second electrode 134. The planarization layer 118 may comprise an organic layer such as photoacryl, an inorganic layer such as SiOx or SiOx, and a plurality of layers of an organic layer.

A light path control layer 150 is disposed on the planarization layer 118. The optical path control layer 150 includes a first region 151 formed of a polymer material having a low refractive index formed over the entire first substrate 110 and a polymer material having a refractive index higher than that of the first region 151 And a second region 153 disposed discontinuously in the first region 151 to change the path of the light emitted from the light emitting layer 132 so that the light travels straight in the upward direction.

Light emitted from the light emitting layer 132 is incident on the light path control layer 150 through the second electrode 134 and the planarization layer 118 at various angles. The light incident on the second region 153 is totally reflected at the interface between the first region 151 having a low refractive index and the second region 153 having a high refractive index within the second region 153, Lt; / RTI > The light incident on the first region 151 is refracted and incident on the second region 153 at the interface between the first region 151 having a low refractive index and the second region 153 having a high refractive index, 2 region 153 and propagates upward. Therefore, the light emitted from the light emitting layer 132 and incident on the light path control layer 150 at an incident angle of a certain angle is transmitted through the light path control layer 150, and the incident angle is significantly reduced.

The second passivation layer 161 may be disposed on the optical path control layer 150. The second passivation layer 161 may be composed of a single layer of an organic layer, a plurality of layers of an organic layer / an inorganic layer or an inorganic layer / an organic layer / an inorganic layer.

An adhesive layer 162 is applied on the second protective layer 161 and a second substrate 160 is disposed on the adhesive layer 162 to attach the second substrate 160 to the display device. As the adhesive layer, any material can be used as long as it has good adhesion and good heat resistance and water resistance. In the present invention, a thermosetting resin such as an epoxy compound, an acrylate compound or an acrylic rubber can be used. In this case, the adhesive layer 162 is cured by irradiating the adhesive layer with light such as ultraviolet rays.

The adhesive layer 162 not only bonds the first substrate 110 and the second substrate 160, but also acts as an encapsulant for preventing moisture from penetrating into the EL display device. Thus, although the term 162 is referred to as an adhesive in the detailed description of the present invention, this is for convenience only, and the adhesive layer may also be referred to as an encapsulant.

The second substrate 160 is an encapsulation cap for encapsulating the electroluminescence display device and may be formed of a material such as a PS (polystyrene) film, a PE (polyethylene) film, a PEN (polyethylene naphthalate) A protective film may be used and glass may be used.

The electroluminescence display device having the above structure includes the light path control layer 150 on the light emitting layer 132 to change the path of the light emitted from the light emitting layer 132 to change the light extraction efficiency of the electroluminescence display device .

The light emitted from the conventional light emitting layer 132 is propagated upward at various angles so that light incident at an angle of more than a critical angle in the light incident on the interface between the layers disposed on the light emitting layer 132 is refracted at the interface, The light is totally reflected at the interface and propagated along the layer, resulting in optical loss.

Therefore, in the present invention, the light emitted from the light emitting layer 132 is propagated through the light path control layer 150 by changing the light path in the vertical direction of the light emitting layer 132, so that the light path control layer 150 is transmitted Most of the incident light enters the interface between the layers at a critical angle or less. Therefore, since total reflection does not occur at the interface, all the light emitted from the light emitting layer 132 can be extracted to the outside, and the light extraction efficiency can be improved.

FIG. 5 is a flow chart showing a method of manufacturing an electroluminescent display device according to a first embodiment of the present invention. FIGS. 6A to 6E are views showing a method of manufacturing an electroluminescent display device, A method of manufacturing an electroluminescent display device according to one embodiment will be described.

As shown in FIGS. 5 and 6A, an inorganic material such as SiOx or SiNx is laminated on a first substrate 110 such as glass or plastic to form a buffer layer 112. The buffer layer 112 may be formed as a single layer or a plurality of layers. Then, an oxide semiconductor, crystalline silicon, or the like is stacked over the entire surface of the substrate 110 by the CVD method, and then the semiconductor layer 122 is formed on the buffer layer 112 by etching. The crystalline silicon layer may be formed by directly laminating crystalline silicon, or may be formed by laminating amorphous silicon and then crystallizing an amorphous material by various crystallization methods such as laser crystallization. On both sides of the crystalline silicon layer, an n ⁺ or p ⁺ -type impurity is doped to form a doping layer.

Thereafter, an inorganic insulating material such as SiOx or SiNx is deposited on the semiconductor layer 122 by CVD (Chemical Vapor Deposition), and an inorganic insulating material such as Cr, Mo, Ta, Cu, Ti, Al, A gate insulating layer 123 and a gate electrode 125 are formed by etching the inorganic insulating material and the metal at a time. The gate insulating layer 123 may be formed over the entire surface of the first substrate 110 and only the gate electrode 125 may be etched.

 An insulating layer 114 is formed by depositing an inorganic insulating material on the entire surface of the substrate 110 on which the gate electrode 125 is formed by the CVD method and a part of the interlayer insulating layer 114 is etched, A first contact hole 114a is formed in which both side surfaces of the layer 122 are exposed.

Thereafter, an opaque metal having good conductivity such as Cr, Mo, Ta, Cu, Ti, Al, or Al alloy is deposited on the first substrate 110 by sputtering and then etched to form a first contact hole A source electrode 127 and a drain electrode 128 electrically connected to the semiconductor layer 122 are formed through the first electrode layer 114a and the driving thin film transistor is disposed on the first substrate 110. [

5 and 6B, an organic insulating material such as photo-acryl is stacked over the entire surface of the first substrate 110 on which the source electrode 127 and the drain electrode 128 are disposed, A layer 116 is formed and a part of the region is etched to form a second contact hole 116a through which the drain electrode 128 of the driving TFT is exposed.

5 and 6C, a metal such as Ca, Ba, Mg, Al, or Ag is deposited and etched on the entire surface of the first substrate 110 to form a second contact hole 116a The first electrode 130 connected to the drain electrode 128 of the driving thin film transistor is formed through the first electrode 130 and the bank layer 131 partitioning the pixel in the boundary region of the pixel P is formed.

The bank layer 131 may be formed first, and the first electrode 130 may be formed.

A light emitting layer 132 is formed on the first electrode 130 and the bank layer 131. A transparent conductive material such as ITO or IZO is deposited on the light emitting layer 132 by a sputtering method and etched, The light emitting element is disposed.

5 and 6D, a planarization layer 118 is formed on the light emitting device, and then an optical path control layer 150 is prepared. After the first substrate 110 on which the light emitting device is formed and the light path control layer 150 are aligned with each other, the light path control layer 150 is attached to the first substrate 110, And a rosuser layer 150.

As shown in FIG. 7, the light path control layer 150 may be formed in a film form. That is, the optical path control layer 150 is formed by applying a polymer material of a first refractive index of a thickness (t) set on a transparent base film 155 having sides of the same length (l1, l2) And a second region 153 formed of a polymer material having a second refractive index larger than the first refractive index and spaced apart from each other in the first region 151.

The thickness t of the first region 151 is equal to the thickness of the second region 153 of the cylindrical shape and the thickness t of the second region 153 is a predetermined angle, And is set so that it can propagate in a direction perpendicular to the surface of the light emitting layer 132 by total reflection. Therefore, the thickness of the second region 153 can be determined according to the refractive index of the first region 151 and the second region 153, the diameter of the second region 153, and the like.

The optical path control layer 150 in the form of a film may be attached to the first substrate 110 entirely including the base film 150 and may be attached while the base film 150 is removed.

As described above, in the present invention, the optical path control layer 150 is formed by forming the optical path control layer 150 in a film form and then attaching the film to the first substrate 110. However, But various methods are possible.

For example, in the present invention, a first region 151 having a cylindrical groove is formed by applying a material having a first refractive index (for example, a polymer material) on the planarization layer 118 and etching the first region 151, A light path control layer 150 having a second region 153 may be formed by applying a material having a large second refractive index (for example, a polymer material) to the inside of the cylindrical groove.

Then, a material having a second refractive index is applied and etched to form a cylindrical second region 153 on the planarization layer 118, and a material having a first refractive index smaller than the second refractive index is formed on the planarization layer 118 And the first region 151 is formed by applying the first region 151 to the first region 151 to form the light path control layer 150.

5 and 6E, after the light path control layer 150 is formed, an organic material or an organic material / an inorganic material is coated on the light path control layer 150 to form the second passivation layer 161, An adhesive layer 162 is formed by applying an adhesive on the second passivation layer 161 and a second substrate 160 such as a glass or a film is placed on the adhesive layer 162. In this state, The adhesive layer 162 is cured to complete the electroluminescent display device.

As described above, in the present invention, the first region and the second region having different refractive indexes are formed in the electroluminescence display device, and the second region is formed into an optical path by total internal reflection, so that light emitted from the light- It is possible to minimize the light loss due to the light refraction at the interfaces of the various layers by making the light guide plate move straight in the outward direction of the display device.

In the above description, the second region for forming the optical path is formed in a cylindrical shape and a plurality of the regions are arranged in a matrix in the pixel region of the display device. However, the total reflection path of the electroluminescence display device of the present invention is limited to this shape But can be configured in various forms.

8A to 8C are plan views showing an optical path control layer of an electroluminescent display device according to a second embodiment of the present invention.

8A, in an electroluminescent display device according to an embodiment of the present invention, a first region 251 of low refractive index of the optical path control layer 250 is formed over a plurality of pixels P, A plurality of high refractive index second regions 253a and 253b having different diameters are disposed in the pixel P. In addition, the second regions 253a and 253b are formed in a cylindrical shape, and the light emitted from the light emitting layer repeats total internal reflection, thereby being advanced in the upward direction, thereby minimizing light loss due to light refraction at the interface of the display device can do.

The light incident on the second regions 253a and 253b of the light path control layer 250 is totally reflected in the second regions 253a and 253b and propagated to the outside as well as the light incident on the first region 251 The light is refracted at the interface between the first region 251 and the second regions 253a and 253b, is incident on the second regions 253a and 253b, is totally internally reflected, and propagates in the vertical direction of the display device.

Light incident on the first region 251 emitted from the light emitting layer and incident on the interface between the first region 251 and the second regions 253a and 253b at an incident angle equal to or greater than a critical angle with respect to the normal, Is reflected at the interface without being refracted into the second regions 253a and 253b at the interface between the region 251 and the second regions 253a and 253b and propagated in the first region 251. [ Therefore, in the light incident on the interface between the first region 251 and the second regions 253a and 253b in the first region 251, a part of the light is still incident on the interface of the display device at a critical angle or more The incident light is incident at an incident angle, and the light is not output to the outside, thereby limiting the improvement of the light efficiency of the display device.

Therefore, in order to improve the light efficiency of the electroluminescence display device, the specific gravity occupied by the second regions 253a and 253b in the light path control layer 250 of the pixel region is maximized, so that the light emitted from the light- Regions 253a and 253b and minimizes propagation through the second region 251. [

The pixel region of the electroluminescence display device may be formed in various shapes as required. Therefore, in order to maximize the specific gravity of the second regions 253a and 253b within the pixel region, the areas of the second regions 253a and 253b may be different depending on the shape of the pixel region. In this embodiment, the second regions 253a and 253b having various sizes (diameters) are formed in the pixel P, so that the specific gravity of the area of the second regions 253a and 253b in the pixel P can be maximized.

8B, the electroluminescent display device of the embodiment of the present invention has the second region 253 of the optical path control layer 250 substantially equal to the size of the pixel P (the second region 253 ) Is equal to the length of one side of the pixel P) so that light emitted from the light emitting layer of the pixel P is propagated through one second region 253, thereby maximizing the light efficiency .

8C, the electroluminescent display of the embodiment of the present invention is formed by forming the second region 253a of the optical path control layer 250 to be substantially equal to the size of the pixel P, The second region 253b having a small diameter is formed in the pixel P which is not covered by the second region 253a of the pixel P so that light emitted from the light- 253b so that the light efficiency can be maximized.

When a cylindrical second region 253a is formed in the rectangular pixel P, a rectangular region in which the second region 253a is not formed is generated in the pixel P due to the difference in shape between the rectangular shape and the circular shape do. Therefore, the electroluminescent display device of this structure can maximize the specific gravity occupied by the second regions 253a and 253b in the pixel P by disposing the second region 253b having a small diameter. When the pixel P is formed in a shape other than a rectangular shape, the number of the second regions of the small diameter 253b may be determined according to the shape.

As described above, the electroluminescent display device according to the present invention has a second region of the optical path control layer 250, which determines the path of light by total internal reflection, according to various factors such as the shape and area of the pixel P, And may be composed of a number.

9 and 10 are views showing the structure of an electroluminescent display device according to a third embodiment of the present invention. An electroluminescent display device of this structure is a bottom emission display device that outputs light in a downward direction. The description of the same contents as those described in Figs. 1 and 4 will be omitted.

9 and 10, a semiconductor layer 322, a gate insulating layer 323, a gate electrode 325, and a source electrode (not shown) are formed on a buffer layer 312 of a first substrate 310 made of transparent glass or plastic 327 and a drain electrode 328, and a first passivation layer 316 and a planarization layer 318 are formed thereon.

The first passivation layer 316 may be formed of an organic layer or a plurality of layers of an organic layer and an inorganic layer, and the planarization layer 318 may be formed of an organic layer such as photoacryl.

On the planarization layer 318, a light path control layer 350 is disposed. The optical path control layer 350 includes a first region 351 made of a polymer material having a first refractive index and a second region 353 made of a polymer material having a second refractive index larger than the first refractive index. The first region 351 is formed over the entire region of the display device and the cylindrical second discontinuous regions 353 are regularly or irregularly arranged in the first region 351 so that the light path control layer 350 The first substrate 310 and the first substrate 310 are totally reflected in the second region 353 and output in a vertical direction with respect to the display device so that the interface between the first substrate 310 and the air, The interface between the interlayer insulating layer 314 and the buffer layer 312, the interface between the passivation layer 316 and the interlayer insulating layer 314, and the light refraction at the interface between the planarization layer 318 and the interlayer insulating layer 316 It is possible to minimize the optical loss caused by the light.

A second contact hole 316a is formed in the first passivation layer 316, the planarization layer 318 and the light path control layer 350 to expose the drain electrode 328 of the thin film transistor. The first electrode 330 is formed on the first contact hole 350 and the first electrode 330 is electrically connected to the drain electrode 328 through the second contact hole 316a. A bank layer 331 is formed in a boundary region of the pixel region and a light emitting layer 332 and a second electrode 334 are formed on the first electrode 330 and the bank layer 331.

The first electrode 330 may be formed of a transparent metal oxide such as ITO or IZO and the second electrode 334 may be formed of a metal and a metal alloy having good reflectivity such as Ca, Ba, Mg, Al, and Ag. A signal is applied to the light emitting layer 332, and at the same time, the light incident from the light emitting layer 332 is reflected. In addition, the second electrode 334 may be formed of an opaque material or a transparent material, and a reflective layer made of a metal having a high reflectivity may be provided on the second electrode 334.

 The light emitting layer 332 includes a light emitting layer for emitting actual light as voltage is applied from the first electrode 330 and the second electrode 334, an electron injection layer and a hole injection layer for injecting electrons and holes respectively into the light emitting layer, An electron transport layer and a hole transport layer that transport the injected electrons and holes to the light emitting layer, respectively.

The second protective layer 334 is applied on the second electrode 334 and the second substrate 360 is attached by the adhesive layer 362 coated on the second protective layer 334 to fabricate an electroluminescent display device .

Therefore, in an electroluminescent display device of the present invention, the light path control layer 350 is formed on the side where light emitted from the light emitting layer 332 is outputted, and the output light is propagated perpendicularly in the downward direction, The light loss due to the refraction can be minimized and the light efficiency of the electroluminescence display device can be maximized.

The electroluminescent display device of the present invention can be applied to various devices such as a mobile device, a video phone, a smart watch, a watch phone, a wearable device, a foldable device, a rollable device, device, a bendable device, a flexible device, a curved device, an electronic organizer, an electronic book, a portable multimedia player (PMP), a personal digital assistant (PDA) Medical devices, desktop PCs, laptop PCs, netbook computers, workstations, navigation, vehicle navigation, vehicle displays, televisions, wall paper displays, notebooks , A monitor, a camera, a camcorder, a home appliance, and the like.

The present invention can be described as follows.

An electroluminescent display device according to an embodiment of the present invention includes a light emitting element including a first electrode and a second electrode, a light emitting layer disposed between the first electrode and the second electrode, and a light emitting element disposed on an output side of the light emitting element, And a light path control layer having a light path for totally reflecting the light of the light path.

According to another aspect of the present invention, an optical path control layer has a first refractive index, a first region formed over the entire region of the light emitting device, a second region having a second refractive index larger than the first refractive index, And a second region for forming the second region.

According to another aspect of the present invention, the optical path control layer may further include a base film on which the first region and the second region are formed.

According to another aspect of the present invention, the second region may be cylindrical.

According to another aspect of the present invention, the first region and the second region may be composed of a polymer material.

According to another aspect of the present invention, a plurality of the second regions may be regularly arranged in the pixels of the light emitting element.

According to another aspect of the present invention, a plurality of the second regions may be irregularly arranged in the pixels of the light emitting element.

According to another aspect of the present invention, the plurality of second regions disposed in the pixels may have different areas.

According to another aspect of the present invention, the second region may be disposed in one pixel of the light emitting element.

According to another aspect of the present invention, the light emitting element may be a top light emitting type.

According to another aspect of the present invention, the light emitting element may be a bottom emission type

An electroluminescent display according to an embodiment of the present invention includes a first substrate including a transistor, a light emitting element disposed on the transistor, the light emitting element including a first electrode, a light emitting layer, and a second electrode, A second substrate, and a first substrate and a second substrate. And an optical path control layer for totally reflecting the light inside the light emitting element.

According to another aspect of the present invention, the light path control layer may be disposed between the light emitting element and the second substrate.

According to another aspect of the present invention, an optical path control layer may be disposed between the transistor and the first electrode.

According to another aspect of the present invention, the optical path control layer may comprise a first region having a first refractive index, and a second region having a second refractive index greater than the first refractive index and including a light path in the first region .

While a great many are described in the foregoing description, it should be construed as an example of preferred embodiments rather than limiting the scope of the invention. Therefore, the invention should not be construed as limited to the embodiments described, but should be determined by equivalents to the appended claims and the claims.

122: semiconductor layer 125: gate electrode
127: source electrode 128: drain electrode
130, 134: electrode 132:
150: light path control layer 151: first region
153: second area

Claims (15)

A light emitting element comprising a first electrode and a second electrode, and a light emitting layer disposed between the first electrode and the second electrode; And
And an optical path control layer disposed on an output side of the light emitting device and having a light path for totally reflecting light inside the light emitting device. The optical path control apparatus according to claim 1,
A first region having a first refractive index and formed over the entire region of the light emitting device; And
And a second region having a second refractive index greater than the first refractive index and formed in the first region to form the light path. The electroluminescent display device of claim 2, wherein the light path control layer further comprises a base film on which the first region and the second region are formed. The electroluminescent display device according to claim 2, wherein the second region is a cylindrical shape. The electroluminescent display of claim 2, wherein the first region and the second region are made of a polymer material. 3. The electroluminescent display device according to claim 2, wherein a plurality of the second regions are regularly arranged in the pixels of the light emitting element. 3. The electroluminescent display device according to claim 2, wherein a plurality of the second regions are irregularly arranged in the pixels of the light emitting element. The electroluminescent display device according to claim 6 or 7, wherein the plurality of second regions disposed in the pixel have different areas. The electroluminescent display device of claim 2, wherein the second region is disposed in one pixel of the light emitting device. The electroluminescent display device of claim 1, wherein the light emitting device is an upper light emitting device. The electroluminescent display device of claim 1, wherein the light emitting device is a bottom emission type. A first substrate including a transistor;
A light emitting element disposed on the transistor, the light emitting element including a first electrode, a light emitting layer, and a second electrode;
A second substrate disposed on the light emitting element; And
And is disposed between the first substrate and the second substrate. And an optical path control layer that totally reflects light inside the light emitting device. 13. The electroluminescent display device of claim 12, wherein the light path control layer is disposed between the light emitting device and the second substrate. The display device according to claim 12, wherein the light path control layer comprises an electroluminescence display device disposed between the transistor and the first electrode 13. The optical path control apparatus according to claim 12, wherein the optical path control layer comprises a first region having a first refractive index, and a second region having a second refractive index larger than the first refractive index and including a light path in the first region, Emitting display

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