KR20170010132A - Display apparatus including light emitting device - Google Patents

Abstract

The present invention discloses a light emitting device and a display apparatus including the same. The display apparatus comprises: a substrate; at least three thin film transistors; an insulation layer; at least three pixel electrodes; and a light emitting device connected to the at least three pixel electrodes, wherein the light emitting device includes: a first conductive semiconductor layer including a first to a third region; a plurality of nanorods located on the first to the third region, respectively, and including a basic layer, a second conductive semiconductor layer, and an activation layer located between the basic layer and the second conductive semiconductor layer; at least three second electrodes located on the nanorods, and electrically connected to the nanorods to be spaced apart from one another; and a first electrode electrically connected to the first conductive semiconductor layer. Nanorods located on the first region and the third region emit light having a shorter peak wavelength than nanorods located on the second region, and the at least three second electrodes, which are located on the first to the third region, respectively, are electrically connected to the at least three pixel electrodes, respectively.

Description

DISPLAY APPARATUS INCLUDING LIGHT EMITTING DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a display device including a light emitting element that emits light of a plurality of wavelengths.

The display device is applied to various applications that are required to provide images to the user. In general, an LCD display, an organic light emitting display, or the like is used as a display device. The LCD display controls the white light emitted from the backlight by using liquid crystal, filters the white light to realize RGB color light, and operates in a manner of implementing various colors by mixing colors of the RGB light.

Such an LCD display requires a liquid crystal for controlling the light emitted from the backlight and a configuration for filtering the white light, so that the contrast ratio is low and the thickness is thick. In addition, due to the characteristics of the structure of the LCD display, there is a limitation in the degree of bending or warping, and it is difficult to realize a flexible display.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display device capable of realizing a unit pixel from a unit element.

Another object of the present invention is to provide a display device capable of reducing the size of a unit pixel and reducing its size and thickness by implementing a unit pixel in a unit pixel.

Another object of the present invention is to provide a light emitting device capable of emitting unit light having different peak wavelengths and capable of realizing a unit pixel in one device.

However, the above-mentioned problems are illustrative, and thus the scope of the present invention is not limited thereto.

A display device according to an aspect of the present invention includes: a substrate; At least three thin film transistors located on the substrate; An insulating layer covering the thin film transistor and including an opening exposing a drain electrode of the thin film transistor; At least three pixel electrodes connected to the drain electrode through the opening; And a light emitting device located on the insulating layer and connected to the at least three pixel electrodes, wherein the light emitting device includes: a first conductive semiconductor layer including a first region, a second region, and a third region; A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer; At least three second electrodes located on the plurality of nanorods and electrically connected to the nanorods and spaced apart from each other; And a first electrode electrically connected to the first conductivity type semiconductor layer, wherein the nano rods located on the first region and the third region have a shorter peak wavelength than the nano rods located on the second region And at least three second electrodes located on each of the first to third regions are electrically connected to each of the at least three pixel electrodes.

The first region may have a first height, the second region may have a second height that is higher than the first height, and the third region may have a third height that is less than the second height.

The first region and the second region may be formed in a stepped shape so as to have a step difference.

The first height and the second height may be the same.

The display device may further include a wavelength conversion unit located at an upper portion or a lower portion of the first area.

The display device may further include a bonding layer disposed between the at least three second electrodes and the pixel electrode.

The thickness of the bonding layer located below the first region may be greater than the thickness of the bonding layer located below the second region.

The display device may further include an underfill portion filling a space between the light emitting element and the insulating layer.

The underfill portion may further cover the side surface of the light emitting element, the upper surface of the underfill portion may be parallel to the upper surface of the light emitting element, the first electrode may be located on the light emitting element, Can be partially covered.

The active layer may include a well layer including In.

The first electrode may be located below the first conductive semiconductor layer.

The light emitting device may further include an insulating material portion surrounding the side surfaces of the nanorods.

The substrate may comprise a flexible polymer material.

The wavelength converting portion may be formed to at least partially cover the second electrode, and the wavelength converting portion may include a via hole for partially exposing the second electrode.

The surfaces of the first region and the third region may be inclined and the nanorods disposed on the first region and the third region may have growth surfaces different from the nanorods disposed on the second region, .

The nanorods disposed on each of the first and third regions may have a semi-polar growth surface.

The light emitted from the nanorods located on the first region may be wavelength-converted by the wavelength conversion unit and may be emitted as red light, and the light emitted from the nanorods located on the second region may be green And the light emitted from the nanorods located on the third region may be blue light.

A display device according to another aspect of the present invention includes: a substrate; At least three pixel electrodes located on the substrate; And a light emitting device located on the insulating layer and connected to the at least three pixel electrodes, wherein the light emitting device has a first region having a first height, a second region having a second height higher than the first height, A first conductive semiconductor layer including a first region having a height, a third region having a height lower than the second height, and a fourth region having a fourth height; A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer; At least three nitride-based transistors located on the fourth region; At least three second electrodes located on the plurality of nano rods and electrically connected to the nano rods and spaced apart from each other and electrically connected to drain electrodes of the at least three nitride transistors; And a first electrode electrically connected to the first conductivity type semiconductor layer, wherein the nano rods located on the first region and the third region have a shorter peak wavelength than the nano rods located on the second region And at least three second electrodes located on each of the first to third regions are electrically connected to each of the at least three pixel electrodes.

A display device according to another aspect of the present invention includes: a substrate; At least three pixel electrodes located on the substrate; And a light emitting device located on the insulating layer and connected to the at least three pixel electrodes, wherein the light emitting device has a first region having a first height, a second region having a second height higher than the first height, And a third region having a height lower than the second height; A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer; At least three second electrodes located on the plurality of nanorods and electrically connected to the nanorods and spaced apart from each other; And a first electrode electrically connected to the first conductivity type semiconductor layer, wherein the nano rods located on the first region and the third region have a shorter peak wavelength than the nano rods located on the second region And at least three second electrodes located on each of the first to third regions are electrically connected to each of the at least three pixel electrodes, and the at least three pixel electrodes are independently controlled do.

A light emitting device according to another aspect of the present invention includes a first region having a first height, a second region having a second height higher than the first height, and a third region having a height lower than the second height, A first conductive semiconductor layer including a first conductive semiconductor layer; A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer; At least three second electrodes located on the plurality of nano rods and electrically connected to the nano rods and spaced apart from each other; And a first electrode electrically connected to the first conductivity type semiconductor layer, wherein a peak wavelength of light emitted from the nanorods located on the first region is greater than a peak wavelength of light emitted from the nanorods located on the second region Which is shorter than the peak wavelength of the light.

The light emitting device may further include a wavelength conversion unit located at an upper portion or a lower portion of the first region.

The light emitting device may further include at least three nitride-based transistors connected to the at least three second electrodes, wherein the first conductivity type semiconductor layer further includes a fourth region having a fourth height, The at least three nitride-based transistors may be located on the fourth region.

According to the present invention, the light emitting device includes first through third sub-pixel regions of different colors, and the unit light emitting device itself can serve as one unit pixel. Thus, the size of the unit pixel can be reduced, and a display device with a higher resolution can be provided. Furthermore, since the liquid crystal layer, the phosphor layer, the polarizing layer and the filter layer are not required as in the case of the LCD display device, the thickness of the display device can be reduced. In addition, the light emitted from the light emitting device has a higher primary color characteristic than the filtered light, and a display device having a high contrast ratio can be provided.

1 is a cross-sectional view illustrating a display device and a light emitting device according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a display device and a light emitting device according to an embodiment of the present invention.
3 is a cross-sectional view illustrating a display device and a light emitting device according to another embodiment of the present invention.
4 is a cross-sectional view illustrating a display device and a light emitting device according to another embodiment of the present invention.
5 is a cross-sectional view illustrating a display device and a light emitting device according to another embodiment of the present invention.
6 and 7 are cross-sectional views illustrating a display device and a light emitting device according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can sufficiently convey the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. It is also to be understood that when an element is referred to as being "above" or "above" another element, But also includes the case where there are other components in between. Like reference numerals designate like elements throughout the specification.

1 and 2 are sectional views for explaining a display device and a light emitting device according to an embodiment of the present invention. Fig. 1 shows a portion corresponding to one pixel of the display device, and Fig. 2 shows a configuration in which a plurality of pixels are arranged.

1, a display device includes a substrate 210, at least three pixel electrodes 290, and a light emitting device 100 including a first electrode 150 and a second electrode 170. Further, the display device includes at least three thin film transistors (TFT) including a transistor semiconductor layer 230, a gate electrode 250, a drain electrode 271 and a source electrode 273, a buffer layer 220, And may further include an insulating layer 240, a second insulating layer 260, a third insulating layer 280, a bonding layer 310, and an underfill portion 320.

The substrate 210 may be formed of an insulating or conductive material, and may also have rigid or flexible characteristics. Further, the substrate 210 may have light transmission or light reflectivity. The optical characteristics of the substrate 210 can be determined according to the direction of a light emitting surface of the display device, that is, a surface that implements the image of the display device. For example, in the case of a display device of a light-emitting type, in which the surface of the display device that implements the image is the bottom surface of the substrate 210, the substrate 210 may have a relatively high light transmittance. For example, the substrate 210 may be formed of a ceramic such as glass, a metal, or a polymer such as PET (polyethylene terephthalate), PEN (polyethylenenaphthalate), polyimide, or the like.

The buffer layer 220 may be located on the substrate 210. The buffer layer 220 can prevent impurities from diffusing into the TFTs on the substrate 210. Buffer layer 220 may include an insulating material, for example, may include SiO ₂ and / or SiN _x. However, the buffer layer 220 may be omitted.

At least three thin film transistors (TFT) may be located on the buffer layer 220. The thin film transistor (TFT) includes a transistor semiconductor layer 230, a gate electrode 250, a drain electrode 271 and a source electrode 273.

Specifically, a plurality of transistor semiconductor layers 230 spaced from each other are disposed on the buffer layer 220. The transistor semiconductor layer 230 is formed corresponding to the number of the thin film transistors (TFT). In this embodiment, at least three transistor semiconductor layers 230 are arranged so as to be spaced apart from each other. The transistor semiconductor layer 230 may be formed of an inorganic semiconductor or an organic semiconductor such as amorphous silicon or polysilicon, and includes a source region, a drain region, and a channel region. The source and drain regions may be formed by doping the transistor semiconductor layer 230 with a dopant (e.g., B, N, or the like).

The first insulating layer 240 is formed to partially cover the transistor semiconductor layer 230. In particular, the first insulating layer 240 may include openings exposing the source and drain regions of the transistor semiconductor layer 230 and may be formed to cover the central region of the transistor semiconductor layer 230. In the first insulating layer 240, a portion covering the center region of the transistor semiconductor layer 230 may function as a gate insulating film. Further, the first insulating layer 240 may further cover the spacing region between the transistor semiconductor layers 230. The first insulating layer 240 may have insulating properties and may have light transmittance. For example, the first insulating layer 240 may comprise SiO ₂ and / or SiN _x .

A gate electrode 250 is positioned on each of the transistor semiconductor layers 230 and is located on the first insulating layer 240. The gate electrode 250 may include at least one of Au, Ag, Cu, Ni, Pt, Pd, Al and Mo or an alloy such as Al: Nd, Mo: W, May be formed of various materials in consideration of the adhesion to the adjacent layer, the flatness of the layer to be laminated, the electrical resistance, the workability, and the like. The gate electrode 250 is connected to a gate line (not shown) capable of controlling on / off signals of the thin film transistor TFT.

The second insulating layer 260 is located on the first insulating layer 240 and the gate electrode 250 and covers the gate electrode 250 in particular. The second insulating layer 260 includes openings exposing the source and gate regions of the transistor semiconductor layer 230. The second insulating layer 260 may have an insulating property and may have light transmittance. For example, the second insulating layer 260 may include SiO ₂ and / or SiN _x.

The drain electrode 271 and the source electrode 273 are electrically connected to the transistor semiconductor layer 230 through the openings of the first and second insulating layers 240 and 260. The drain electrode 271 and the source electrode 273 are connected to the drain region and the source region of the transistor semiconductor layer 230, respectively. The drain electrode 271 and the source electrode 273 may partially cover the second insulating layer 260. The drain electrode 271 and the source electrode 273 may include at least one of Au, Ag, Cu, Ni, Pt, Pd, Al and Mo or an alloy such as Al: Nd, Mo: But it is not limited thereto, and may be formed of various materials in consideration of the adhesion with the adjacent layer, the flatness of the layer to be laminated, the electrical resistance and the workability.

Through this thin film transistor (TFT), the current supplied to each of at least three pixel electrodes 290 can be independently controlled.

The third insulating layer 280 covers the thin film transistor (TFT), and includes openings that partially expose the drain electrode 271 of each thin film transistor (TFT). The third insulating layer 280 can protect the thin film transistor (TFT) from the outside, and effectively isolate each transistor (TFT) from each other. The third insulating layer 280 may be formed thicker than the first and second insulating layers 240 and 260. The third insulating layer 280 may be a single layer or multiple layers including at least one of an inorganic insulating layer and an organic insulating layer. For example, the third insulating layer 280 may be formed of SiO ₂ , SiN _x , SiON, Al ₂ O ₃ , TiO ₂ , Ta Inorganic insulating films such as SiO ₂ O ₅ , HfO ₂ , ZrO ₂ , BST and PZT. In addition, organic insulating films such as polymer materials such as PMMA and PS, polymer derivatives having phenol groups, acrylic polymers, . ≪ / RTI > In addition, the upper portion of the third insulating layer 280 may be formed substantially flat, in which case the third insulating layer 280 may include a planarization layer formed on the upper portion thereof.

The pixel electrode 290 is formed corresponding to each of at least three thin film transistors TFT and is electrically connected to the drain electrode 271 through the opening of the third insulating layer 280. The pixel electrode 290 may be formed of a transparent conductive material or a metal. The pixel electrode 290 may be formed of indium tin oxide (ITO), zinc oxide (ZnO), zinc indium tin oxide (ZITO), or the like, for example, (Gallium Indium Tin Oxide), GIO (Gallium Indium Oxide), GZO (Gallium Zinc Oxide), AZO (Aluminum Doped Zinc Oxide), FTO (Fluorine Tin Oxide), ZTO (Zinc Tin Oxide) Or a transparent metallic material such as a Ni / Au laminated structure. The pixel electrode 290 may be formed of a metal such as Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, or Mo, And the pixel electrode 290 may include a light reflecting reflective layer. The pixel electrode 290 may be formed as a p-type or n-type bus electrode line electrically connected to the first electrode 150 or the second electrode 170 of the light emitting device.

The light emitting device 100 is located on the third insulating layer 290 and the pixel electrode 290. The light emitting device 100 includes a first conductive semiconductor layer 120, a plurality of nano rods 130 disposed on the lower surface of the first conductive semiconductor layer 120, a first electrode 150, 170 and a wavelength conversion unit 160. [ Further, the light emitting device 100 may further include an insulating material 140 surrounding the sides of the plurality of nano rods 130, and may further include a growth substrate (not shown). The light emitting device 100 may include a first unit pixel region 301, a second sub pixel region 302, and a third unit pixel region 302. The light emitting device 100 may include one unit pixel, And a pixel region 303 as shown in FIG.

The first conductivity type semiconductor layer 121 may include a III-V series nitride semiconductor, for example, a nitride semiconductor such as (Al, Ga, In) N. The first conductivity type semiconductor layer 121 may include n-type impurities (for example, Si, Ge, Sn). The first conductive semiconductor layer 121 may be grown in a chamber using a known method such as MOCVD. In addition, the first conductivity type semiconductor layer 121 includes the first to third regions 101, 102, and 103. At this time, the first region 101 may have a first height, the second region 102 may have a second height, and the third region 103 may have a third height. The second height of the second region 102 is greater than the first height or the third height. The first height and the third height may be substantially the same, but are not limited thereto, and the first height and the third height may be different from each other.

Each of the nano rods 130 may include an active layer 133 located between the base layer 131 and the second conductivity type semiconductor layer 135 and between the base layer 131 and the second conductivity type semiconductor layer 135. have. Each of the base layer 131, the second conductivity type semiconductor layer 135, and the active layer 133 may include a nitride semiconductor such as (Al, Ga, In) N. The base layer 131 may have the same conductivity type as that of the first conductivity type semiconductor layer 120, and thus may be doped with n-type impurity including n-type impurities. The second conductivity type semiconductor layer 135 may have a conductivity type opposite to that of the first conductivity type semiconductor layer 120 or the base layer 131. For example, the second conductivity type semiconductor layer 135 may include a p-type dopant such as Mg, Sr, and Ba and may be doped with p-type. The active layer 133 may include a multiple quantum well structure (MQW), and the composition ratio of the nitride-based semiconductor may be adjusted so as to emit a desired wavelength. In particular, the active layer 133 may include a well layer including In, and may include, for example, a multiple quantum well structure composed of an InGaN well layer and a GaN barrier layer (or an InGaN barrier layer).

The peak wavelength of the light emitted from the nano rods 130 located on the first region 101 (or the third region 103) is larger than the peak wavelength of the nano rods 130 located on the second region 102, May be shorter than the peak wavelength of the light emitted from the light source. For example, the light emitted from the nanorods 130 located on the first region 101 (or the third region 103) is blue light, and the nanorods 130 located on the second region 102 The light emitted from the light source 130 may be green light. At this time, the blue light emitted from the nano-rods 130 located on the first region 101 is wavelength-converted by the wavelength converting portion 160 located above or below the first conductive type semiconductor layer 120 And can be emitted to the outside as red light. As a result, red light is emitted in the vertical direction of the first region 101, green light is emitted in the vertical direction of the second region 102, and blue light is emitted in the vertical direction of the third region 103 . The red light is mainly emitted through the first sub-pixel region 301, the green light is mainly emitted through the second sub-pixel region 302, and the blue light is mainly emitted through the third sub-pixel region 303 . Accordingly, the first sub-pixel region 301 may correspond to the R region (red region) of the unit pixel, the second sub-pixel region 302 may correspond to the G region (green region) And the third sub-pixel region 303 may correspond to the B region (blue region) of the unit pixel.

As described above, the light emitting device 100 includes the first to third sub-pixel regions 301, 302, and 303 of different colors, and can function as one unit pixel as the light emitting device 100 itself. Accordingly, the elements serving as sub-pixels are not separated from each other, and the first to third sub-pixel regions are provided in one light emitting element, so that the size of the unit pixel can be reduced. By miniaturizing the unit pixel, a higher resolution display device can be provided. Furthermore, since the liquid crystal layer, the phosphor layer, the polarizing layer and the filter layer are not required as in the case of the LCD display device, the thickness of the display device can be reduced.

In addition, the active layer 133 of the light emitting device 100 is included in the plurality of nano rods 130, so that the linearity of the light emitted from the active layer 133 in the vertical direction can be improved. The light emitted from the active layer 133 is totally reflected within the nano-rod 130 and is reflected by the nano-rod 130 in the longitudinal direction (vertical direction) of the nano- Direction) is greatly increased. That is, since the light emitting device 100 includes the nano-rods 130, it is possible to control the traveling direction of the light in the vertical direction, thereby greatly reducing the mixing of lights of different wavelengths in the light emitting device 100 . This minimizes the change in the color coordinates of light emitted from each of the first to third sub pixel regions 301, 302, and 303, so that the color of the display device can be maintained close to the intended color.

Hereinafter, the method of forming the nano rods 130 will be described in more detail.

The first conductive semiconductor layer 120 of the light emitting device 100 is grown in the MOCVD chamber. The first conductivity type semiconductor layer 120 can be grown by, for example, introducing a Ga source, an N source, and an Si dopant source into the MOCVD chamber. Next, a first region 101 having a first height, a second region 102 having a second height, and a third region 102 having a third height are formed on the surface of the first conductivity type semiconductor layer 120 through an etching process. Regions 103 are formed.

The nanorods 130 may be formed in-situ within the MOCVD chamber. Specifically, the nano rods 130 can be grown at a temperature lower than the normal nitride semiconductor growth temperature. For example, Ga and N precursors are fed into the reactor at a flow rate of 30 to 70 sccm and 1000 to 2000 sccm, respectively, at a temperature of 400 to 600 ° C. and at atmospheric pressure or a slight positive pressure for 20 to 40 minutes and at the same time, SiH 4 is supplied at a flow rate of 5 to 20 sccm And then the active layer 133 and the second conductivity type semiconductor layer 135 are grown on the base layer 131 to grow the nano rods 130. In this way, . The well layer of the active layer 133 is formed in the growth chamber at a flow rate of 30 to 70 sccm, 10 to 40 sccm, and 1000 to 2000 sccm, respectively, at a temperature of 400 to 500 DEG C and at atmospheric pressure or a slight positive pressure, And can be grown. The second conductivity type semiconductor layer 135 is formed by depositing Ga and N precursors at a flow rate of 30 to 70 sccm and 1000 to 2000 sccm for 20 to 40 minutes at a temperature of 400 to 600 占 폚 and at atmospheric pressure or a slight positive pressure, And simultaneously introducing Cp2Mg into the growth chamber at 5 to 20 sccm. In this process condition, the growth in the vertical direction is dominant, so that the single crystal semiconductor layers in the form of nano rods 130, which are not thin films, can be grown. At this time, the grown nanorods may have vertical sides and / or inclined sides.

On the other hand, an In source is introduced into the MOCVD chamber during growth of the active layer 133, particularly during growth of the well layer of the active layer 133. In the MOCVD chamber, the light emitting elements are formed on a wafer rotating at a constant RPM. At this time, when there is a step on the surface, a difference in the flow rate of the In source gas occurs depending on the height. Accordingly, a layer having a relatively high In concentration is grown in a layer grown at a relatively high position, and a layer having a relatively low In concentration is grown in a layer grown at a relatively low position. Therefore, an InGaN layer containing a relatively high composition ratio In can be grown on the well layer of the active layer 133 located on the first region 101 and the third region 103, An InGaN layer containing a relatively low composition ratio In can be grown on the well layer of the active layer 133 located in the active layer 133. [ The wavelength of light emitted from the nanorods 130 located on the second region 102 is longer than the wavelength of light emitted by the nanorods 130 located on the first and third regions 103 . By using this method, the light emitting device 100 in which light in the blue region and light in the green region can be simultaneously emitted can be realized.

Referring again to Figures 1 and 2, the insulating material 140 may cover at least some of the sides of the nanorods 130. Also, a part of the nano rods 130 is exposed without being covered with the insulating material portion 140. The insulating material 140 may cover the side surfaces of the nano rods 130 and may protect the nano rods 130. In the process of forming the first electrode 150, A part of it is formed on the side surface of the nano-rod 130 to prevent an electrical short-circuit phenomenon through the side surface of the nano-rods 130 from occurring.

Further, the insulating material portion 140 may have optical semipermeability or light reflectivity. Further, the refractive index of the insulating material 140 may be lower than the refractive index of the nitride-based semiconductor forming the nano rods 130. The insulator 140 reflects light emitted to the side surface of the nano-rod 130 by having light reflectivity so that the traveling direction of the light is the longitudinal direction (vertical direction) of the nano-rod 130. Since the insulating material 140 has a refractive index smaller than that of the nano rods 130, the total reflection of the light is promoted at the interface between the insulating material 140 and the nano rods 130, (Vertical direction). Accordingly, it is possible to reduce the mixing of lights of different wavelengths in the light emitting device 100, and to minimize the change of the color coordinates of light emitted from each of the first to third sub pixel regions 301, 302, and 303 So that the color of the display device can be maintained close to the intended color. Vagina insulator 140 is, for example, may include SiO ₂ and / or SiN _x, may further include a light-reflective particles, such as TiO ₂ particles.

The first electrode 150 is located on the nanorods 130 located on each of the first to third regions 101, 102 and 103 so that the first electrode 150 is at least three Electrode. The first electrodes 150 are electrically connected to the second conductive semiconductor layer 135 of the nano-rods 130 and may be connected to the pixel electrodes 290, respectively. Accordingly, at least three first electrodes 150 may be positioned corresponding to positions of at least three pixel electrodes 290, respectively. However, the present invention is not limited thereto.

The first electrode 150 may be formed of a transparent conductive material or a metal. For example, the first electrode 150 may be formed of indium tin oxide (ITO), zinc oxide (ZnO), zinc tin oxide (ZITO), or the like, , Zinc Indium Oxide (ZIO), Zinc Tin Oxide (GTO), Gallium Indium Tin Oxide (GITO), Gallium Indium Oxide (GIO), Gallium Zinc Oxide (AZO), Aluminum Doped Zinc Oxide (AZO), Fluorine Tin Oxide ) Or the like or a transparent metallic material such as a Ni / Au laminated structure. The first electrode 150 may be formed of a material such as Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Mo or the like Metallic material. When the display device is a top surface light emitting type, the first electrode 150 is formed of a reflective layer containing at least one of Ti, Pt, Pd, Rh, W, Ti, Al, Mg, Ag and Au, To prevent damage of the reflective layer through mutual diffusion of the substance and the external material, and may include a cover layer including Au, Ni, Ti, Cr, and the like.

The second electrode 170 is electrically connected to the first conductive semiconductor layer 120. In this embodiment, the second electrode 170 is disposed on the first conductive semiconductor layer 120 and may cover the entire upper surface of the first conductive semiconductor layer 120. In the present embodiment, the first electrodes 150 located on the first to third regions 101, 102, and 103 are insulated from each other and connected to different thin film transistors (TFTs). On the other hand, the second electrode 170 is integrally formed and is formed as a common electrode. The second electrode 170 may be formed as an n-type bus electrode connecting the plurality of light emitting elements to each other.

The second electrode 170 may be formed of a transparent conductive material or a metal. For example, when the top surface emitting type in which the image of the display device is implemented is the top surface emitting type, the second electrode 170 may be formed of ITO (Indium Tin Oxide), ZnO (Zinc Oxide), ZINO (Zinc Indium Tin Oxide) Transparent conductive materials such as zinc oxide (ZnO), zirconium tin oxide (ZTO), gallium indium tin oxide (GITO), gallium indium oxide (GIO), gallium zinc oxide (GZO), aluminum doped zinc oxide (AZO), and fluorine tin oxide Or a transparent metallic material such as a Ni / Au laminated structure. The second electrode 170 may be formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Mo, and the like. In this case, the second electrode 170 may include a reflective layer including at least one of i, Pt, Pd, Rh, W, Ti, Al, Mg, Ag, and Au, Preventing damage to the reflective layer through mutual diffusion, and may include a cover layer including Au, Ni, Ti, Cr, and the like.

The wavelength converter 160 is located above or below the first region 101. In this embodiment, the wavelength converting portion 160 may be positioned on the upper surface of the first conductive semiconductor layer 120 located above the first region 101. Alternatively, the position of the wavelength conversion section 160 may be changed depending on the type of the light emitting device, and in some embodiments, the wavelength conversion section 160 may be located on the first electrode 150.

The wavelength converter 160 may include a material capable of changing the wavelength of light, and in particular, it may wavelength-convert light having a short wavelength into light having a long wavelength. In this embodiment, the wavelength converter 160 can convert the blue light into the red light. The wavelength converting unit 160 may be provided in a form of a phosphor dispersed in a carrier, may be provided in the form of a single crystal or polycrystalline phosphor sheet, or may be provided in a form including a quantum dot material. The wavelength converting unit 160 may include nitride-based, silicate-based, and fluoride-based phosphors.

The first electrodes 150 of the light emitting device 100 may be connected to the pixel electrodes 290 and the bonding layer 310 may be further formed between the first electrode 150 and the pixel electrode 290 . The bonding layer 310 may electrically connect the first electrode 150 and the pixel electrode 290 and may be formed to have different thicknesses depending on the step of the first to third regions 101, have. The bonding layer 310 may include a transparent conductive material and / or metal, and a material for forming the bonding layer 310 may be variously applied according to the image forming direction of the display device.

Meanwhile, the light emitting device 100 may be modified into various forms. For example, as shown in FIGS. 3 to 5, the light emitting device 100 may be modified into a horizontal type, a flip chip type, or the like.

3, the light emitting device 100a may further include a growth substrate 110. The first conductivity type semiconductor layer 120 and the nano rods 130 may be formed on the growth substrate 110, Lt; / RTI > Further, a portion of the top surface of the first conductive semiconductor layer 120 may be exposed, and a second electrode 171 may be formed on the exposed top surface of the first conductive semiconductor layer 120. Particularly, in this embodiment, since the light advancing direction corresponds to the upper portion of the light emitting device 100a, the wavelength converting portion 160 is located on the first electrode 150 positioned on the first region 101 . At this time, the wavelength converting portion 160 may include at least one via hole 160a for forming an electrical connection of the first electrode 150. [

4, the light emitting device 100b of FIG. 4 is substantially similar to the light emitting device 100a of FIG. 3, but includes a first and a second regions 101 and 103, Type semiconductor layer 120 may be formed. Through this inclination, the concentration of In contained in the active layer 133 located on the first and third regions 101 and 103 is reduced, and the nanorods 130 emitting light of a relatively short wavelength .

The first and third regions 101 and 103 may have different growth planes than the second region 102 by having an inclination. Accordingly, the nanorods 130 formed on the first and third regions 101 and 103 are grown to have different growth planes from the nanorods 103 grown on the second region 102. For example, when the growth plane of the second region 102 is the C plane, the growth planes of the first and third regions 101 and 103 may be non-polar or semi-polar planes. In the case where the growth surface is a nonpolar or semi-polar surface, the probability of trapping in the semiconductor in which In is grown is lower than that of the C surface. Therefore, the In of the active layer 133 grown on the first and third regions 101 and 103 The composition ratio can be further reduced.

On the other hand, the inclination of the first and third regions 101 and 103 can be similarly applied to the light emitting device 100 of FIG.

5, the light emitting device 100c of FIG. 5 is substantially similar to the light emitting device 100a of FIG. 3, but differs in that the light emitting device 100c is formed in the form of a flip chip. The light emitting device 100c may include an upper surface of the first conductivity type semiconductor layer 120 as a light emitting surface so that the wavelength conversion portion 160 is located on the first conductivity type semiconductor layer 120 . The growth substrate 110 is separated from the first conductivity type semiconductor layer 120 but the growth substrate 110 is not limited to the first conductivity type semiconductor layer 120 It is possible.

The light emitting device 100c may further include a light-transmitting protective layer 181 disposed on the second region 102 and the third region 103. The light emitting device 100c may include a light- And a light blocking layer 183 disposed on the light blocking layer 183. The second electrode 171 is disposed on the lower surface of the first conductivity type semiconductor layer 120 in the light emitting device 100c so that the first conductivity type semiconductor layer 120 is exposed when the light transmitting protection layer 181 is exposed And the first conductivity type semiconductor layer 120 can be protected. The light blocking layer 183 may block light emitted from a region where the second electrode 171 is formed, that is, a portion not corresponding to the sub pixel region. As a result, light is emitted from a portion that does not correspond to the sub-pixel region, so that light can not be intentionally mixed or the color coordinate of the light displayed on the display device can be prevented from being deformed.

Referring to FIGS. 1 and 2 again, the display device may further include an underfill portion 320 filling a space between the light emitting device 100 and the third insulating layer 280. Further, the underfill portion 320 may further cover the side surface of the light emitting device 100, and may further fill a space between the plurality of light emitting devices 100. [ The upper surface of the underfill portion 320 may be substantially parallel to the upper surface of the light emitting device 100 and the second electrode 170 may further cover the upper surface of the underfill portion 320. The second electrode 170 thus formed may extend through the upper surface of the underfill portion 320 to connect the first conductivity type semiconductor layers 120 of the other light emitting device 100 adjacent to the first light emitting device 100 have. Accordingly, the second electrode 170 may function as a common electrode for the plurality of light emitting devices 100. [

The underfill portion 320 can support and protect the light emitting element 100. In addition, the underfill portion 320 may have insulating properties and light reflectivity. Since the underfill portion 320 has the light reflecting property, it is possible to improve the vertical direction straightness of the light emitted from the active layer 133. In addition, the underfill portion 320 may be formed of a polymer material having a flexible characteristic. In this case, when the display device is implemented as a flexible display, defective display devices due to damage to the underfill portion 320 can be prevented.

2 is a cross-sectional view for explaining a case where the display device including the above-described structures is formed of a plurality of pixels PX. As shown in FIG. 2, one unit light emitting device 100 forms one unit pixel PX. At this time, the size of the unit pixel PX may be 10 μm × 10 μm or less. A plurality of such light emitting devices 100 may be arranged to implement a display device including a plurality of pixels PX. Such a display device is capable of reducing the thickness of the display device by enabling the pixel PX only by the light emitting element 100 and the light emitted from the light emitting element 100 is higher in color than the filtered light , A display device having a high contrast ratio can be provided. Further, since the light emitting device 100 having a plurality of wavelengths can be manufactured from a single wafer and a display device using the same can be formed, a display device having excellent mass productivity can be provided.

Also, the display device according to the present embodiment, in which the size of the unit pixel PX is relatively small, can be applied to a portable device requiring a relatively small size display, for example, a smart phone, a wearable device, and the like. Furthermore, by forming the substrate 210 from a material having a flexible characteristic, a display device having a curved surface can be provided, and further, a flexible display device can be realized.

In the above-described embodiments, the display device is an active-matrix display device including a thin film transistor (TFT), but the present invention is not limited thereto. In some embodiments, the display device does not include a thin film transistor (TFT), and the first electrode 150 and the second electrode 170 of the plurality of light emitting elements are passively connected to the bus electrode line in the form of a lattice matrix - a matrix display device. Each pixel electrode formed in this passive-matrix form can be controlled independently.

Further, in the above-described embodiment, a display device including a light emitting device 100 that emits light of RGB, at least three pixel electrodes 290, and at least three thin film transistors (TFTs) will be described. That is, in the above-described embodiment, a display device having unit pixels including emission light of RGB is described, but the present invention is not limited thereto. In various embodiments, the number of thin film transistors (TFT) can be changed according to the type of light emitted from the light emitting element 100. [ For example, the light emitting device 100 may further include an additional light emitting device (not shown), in which case the additional light emitting device may also be connected to a further thin film transistor (TFT).

6 and 7 are cross-sectional views illustrating a display device and a light emitting device according to another embodiment of the present invention. 6 and 7 show a light emitting device applied to a display device, and other configurations of the display device are omitted for convenience of explanation.

The light emitting device 100d of FIGS. 6 and 7 is substantially similar to the light emitting device 100 of FIGS. 1 and 2, but differs in that it further includes a nitride-based transistor 400. The light emitting device 100d of this embodiment will be described mainly on the following differences.

The display device includes a substrate 210, at least three pixel electrodes 290, and a light emitting device 100 including a first electrode 150 and a second electrode 170. Further, the buffer layer 220, the bonding layer 310, and the underfill portion 320 may be further included. The light emitting device 100d includes a first conductive semiconductor layer 120, a plurality of nano rods 130 disposed on a lower surface of the first conductive semiconductor layer 120, a first electrode 150, 170, a wavelength conversion unit 160, and a nitride-based transistor 400. In this embodiment, the light emitting device 100d may include at least three nitride-based transistors 400. [ Accordingly, the thin film transistor (TFT) in the display device can be omitted.

7 shows a side cross-sectional view corresponding to A-A 'in Fig. Referring to FIG. 7, the first conductivity type semiconductor layer 120 further includes a fourth region 104 having a fourth height. The height of the fourth region 104 may be lower than the first height, but is not limited thereto. The nitride-based transistor 400 may be formed on the fourth region.

The nitride-based transistor 400 may be formed in various shapes such as a vertical type and a horizontal type. For example, the nitride-based transistor 400 may include a channel layer 410, a barrier layer 420, a gate electrode 400, a drain electrode 451, and a source electrode 453. In addition, the nitride-based transistor 400 may further include an insulating layer 430 and a substrate (not shown).

The substrate may be a growth substrate such as a sapphire substrate, a GaN substrate, a SiC substrate, a Si substrate, or the like, and is not particularly limited as long as the substrate can grow the nitride based semiconductor layer.

The channel layer 410 may be formed of a nitride-based semiconductor, for example, a two-component system such as undoped GaN or InN, a three-component system such as AlGaN or InGaN, or a four-component nitride semiconductor such as AlInGaN. In addition, the channel layer 410 may be doped n-type or p-type, or may be an undoped nitride-based semiconductor. On the other hand, the barrier layer 420 is located on the channel layer 410. The barrier layer 420 is formed of a nitride semiconductor, for example, a two-component semiconductor such as undoped GaN or InN, a three-component semiconductor such as AlGaN or InGaN, or a four-component nitride semiconductor such as AlInGaN. In addition, the barrier layer 420 may be doped n-type or p-type, or may be an undoped nitride-based semiconductor.

The nitride based semiconductor forming the channel layer 410 may be a material having a smaller band gap than the second nitride based semiconductor forming the barrier layer 420. For example, the channel layer 410 may be undoped GaN , The barrier layer 420 may be AlGaN. Accordingly, the 2DEG can be formed at the interface between the channel layer 410 and the barrier layer 420. The gate electrode 440 is located on the barrier layer 420 and an insulating layer 430 may be interposed between the gate electrode 440 and the barrier layer 420. The insulating layer 430 may serve as a gate insulating layer. The drain electrode 451 and the source electrode 453 are located on the barrier layer 420. On the other hand, an intermediate layer 460 may be interposed between the nitride-based transistors 400. The intermediate layer 460 may prevent electrical conduction between the nitride-based transistor 400 and the first conductivity type semiconductor layer 120.

The drain electrode 451 of the nitride-based transistor 400 may be electrically connected to the first electrode 150. The first electrode 150 and the drain electrode 451 may be formed through wiring through a step coverage method so that the insulating material 140 is formed on the side surface of the second region 102 and the side surfaces of the nitride- As shown in Fig.

The shape of the nitride-based transistor 400 is not limited thereto, and various types of nitride-based transistors 400 may be applied to the light-emitting device 100d.

According to this embodiment, the thin film transistor (TFT) located on the substrate 210 can be omitted through the light emitting element 100d including the nitride-based transistor 400. [ Therefore, the thickness of the display device can be further reduced.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the following claims.

Claims (22)

Board;
At least three thin film transistors located on the substrate;
An insulating layer covering the thin film transistor and including an opening exposing a drain electrode of the thin film transistor;
At least three pixel electrodes connected to the drain electrode through the opening; And
And a light emitting element which is located on the insulating layer and is connected to the at least three pixel electrodes,
The light-
A first conductive semiconductor layer including a first region, a second region, and a third region;
A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer;
At least three second electrodes located on the plurality of nanorods and electrically connected to the nanorods and spaced apart from each other; And
And a first electrode electrically connected to the first conductive type semiconductor layer,
Wherein the nanorods located on the first and third regions emit light having a shorter peak wavelength than the nanorods located on the second region,
And at least three second electrodes located on each of the first to third regions are electrically connected to each of the at least three pixel electrodes.
The method according to claim 1,
Wherein the first region has a first height, the second region has a second height that is higher than the first height, and the third region has a third height that is less than the second height.
The method of claim 2,
Wherein the first region and the second region have step differences.
The method of claim 3,
Wherein the first height and the third height are the same.
The method according to claim 1,
And a wavelength conversion unit located at an upper portion or a lower portion of the first region.
The method according to claim 1,
And a bonding layer disposed between the at least three second electrodes and the pixel electrode.
The method of claim 6,
Wherein the thickness of the bonding layer located below the first region is greater than the thickness of the bonding layer located below the second region.
The method according to claim 1,
And an underfill portion filling a space between the light emitting element and the insulating layer.
The method of claim 8,
Wherein the underfill portion further covers the side surface of the light emitting element, the upper surface of the underfill portion is parallel to the upper surface of the light emitting element, the first electrode is located on the light emitting element, and at least partially covers the underfill portion.
The method according to claim 1,
Wherein the active layer comprises a well layer containing In.
The method according to claim 1,
Wherein the first electrode is located under the first conductive type semiconductor layer.
The method according to claim 1,
Wherein the light emitting device further comprises an insulating material portion surrounding a side surface of the nano-rods.
The method according to claim 1,
Wherein the substrate comprises a flexible polymer material.
The method according to claim 1,
Wherein the wavelength converting portion is formed to at least partially cover the second electrode, and the wavelength converting portion includes a via hole for partially exposing the second electrode.
The method of claim 2,
Wherein the surfaces of the first region and the third region are inclined, and the nanorods disposed on the first region and the third region respectively have a growth surface different from the nanorods disposed on the second region, .
16. The method of claim 15,
Wherein the nanorods disposed on the first region and the third region have a semi-polar growth surface.
The method of claim 2,
The light emitted from the nano-rods located on the first region is wavelength-converted by the wavelength converter and emitted as red light,
The light emitted from the nanorods located on the second region is green light,
And the light emitted from the nano-rods located on the third region is blue light.
Board;
At least three pixel electrodes located on the substrate; And
And a light emitting element which is located on the insulating layer and is connected to the at least three pixel electrodes,
The light-
A first region having a first height, a second region having a second height higher than the first height, a third region having a third height lower than the second height, and a fourth region having a fourth height A first conductive semiconductor layer;
A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer;
At least three nitride-based transistors located on the fourth region;
At least three second electrodes located on the plurality of nano rods and electrically connected to the nano rods and spaced apart from each other and electrically connected to drain electrodes of the at least three nitride transistors; And
And a first electrode electrically connected to the first conductive type semiconductor layer,
Wherein the nanorods located on the first and third regions emit light having a shorter peak wavelength than the nanorods located on the second region,
And at least three second electrodes located on each of the first to third regions are electrically connected to each of the at least three pixel electrodes.
Board;
At least three pixel electrodes located on the substrate; And
And a light emitting element which is located on the insulating layer and is connected to the at least three pixel electrodes,
The light-
A first conductive semiconductor layer including a first region having a first height, a second region having a second height higher than the first height, and a third region having a third height lower than the second height;
A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer;
At least three second electrodes located on the plurality of nanorods and electrically connected to the nanorods and spaced apart from each other; And
And a first electrode electrically connected to the first conductive type semiconductor layer,
Wherein the nanorods located on the first and third regions emit light having a shorter peak wavelength than the nanorods located on the second region,
Wherein at least three second electrodes located on each of the first to third regions are electrically connected to each of the at least three pixel electrodes, and the at least three pixel electrodes are independently controlled.
A first conductivity type semiconductor layer including a first region having a first height, a second region having a second height higher than the first height, and a third region having a height lower than the second height;
A plurality of nano rods located on each of the first to third regions, the nano rods including a base layer, a second conductivity type semiconductor layer, and an active layer disposed between the base layer and the second conductivity type semiconductor layer;
At least three second electrodes located on the plurality of nano rods and electrically connected to the nano rods and spaced apart from each other; And
And a first electrode electrically connected to the first conductive type semiconductor layer,
Wherein a peak wavelength of light emitted from the nano-rods located on the first region is shorter than a peak wavelength of light emitted from the nano-rods located on the second region.
The method of claim 20,
And a wavelength conversion unit positioned above or below the first region.
The method of claim 20,
Further comprising at least three nitride-based transistors each connected to the at least three second electrodes,
Wherein the first conductivity type semiconductor layer further comprises a fourth region having a fourth height, and the at least three nitride-based transistors are located on the fourth region.

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